Sony Patent | Dimming Device, Image Display Device, And Display Device

Patent: Dimming Device, Image Display Device, And Display Device

Publication Number: 20200264486

Publication Date: 20200820

Applicants: Sony

Abstract

A dimming device includes a first substrate, a second substrate, and a light emitting stacked body that includes a first electrode, a dimming layer, and a second electrode that are stacked; the dimming layer has a stacked structure of a reduction coloring layer, an electrolyte layer, and an oxidation coloring layer; when the number of atoms of a metal contributing to reduction reaction in a compound contained in the reduction coloring layer is denoted by [Re] and the number of atoms of a metal contributing to oxidation reaction in a compound contained in the oxidation coloring layer is denoted by [Ox], the value of [Re]/[Ox] is within a prescribed range; alternatively, when the thickness of the reduction coloring layer is denoted by T.sub.Re and the thickness of the oxidation coloring layer is denoted by T.sub.Ox, the value of T.sub.Re/T.sub.Ox is within a prescribed range.

TECHNICAL FIELD

[0001] The present disclosure relates to a dimming device, an image display device including the dimming device, and a display device including the image display device, and more specifically, for example, relates to a display device used for a head-mounted display (HMD).

BACKGROUND ART

[0002] In recent years, augmented reality (AR) technology that synthesizes and presents a virtual object and various kinds of information in a form of electronic information to a real environment (or a part thereof) as additional information has attracted attention. In order to achieve the augmented reality technology, for example, a head mounted display has been studied as a device for presenting visual information. In addition, as an application field, work support in a real environment has been expected, and examples thereof include provision of road guidance information and provision of technical information to an engineer who performs maintenance or the like, for example. Particularly, a head mounted display is very convenient because of not occupying hands. Furthermore, even in a case where a person wants to enjoy videos and images while moving outdoors, the person can capture videos, images, and an external environment at the same time in the field of view. Therefore, the person can move smoothly.

[0003] A virtual image display device (display device) for causing an observer to observe a two-dimensional image formed by an image forming device as an enlarged virtual image by a virtual image optical system is well known. In addition, by forming a virtual image based on a two-dimensional image in the display device, an observer can view the formed virtual image superimposed on an image of an outside world. By the way, in a case where an environment around the display device is very bright or depending on contents of the formed virtual image, a sufficient contrast cannot be imparted to a virtual image observed by an observer disadvantageously. Therefore, means for solving such a problem, that is, a virtual image display device (display device) including a dimming device is well known from, for example, Japanese Patent Application Laid-Open No. 2012-252091.

CITATION LIST

Patent Document

Patent Document 1: Japanese Patent Application Laid-Open No. 2012-252091

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

[0004] However, in a case where a dimming layer included in a dimming device contains an electrochromic material and color changes of a substance generated by oxidation-reduction reaction of the electrochromic material are practically used to change the transmittance of light, a coloring phenomenon in which a coloring state is left a little in the dimming layer even in a state where voltage is not applied to the dimming layer and a bubble occurrence phenomenon in which bubbles occur in the dimming layer while the dimming layer repeats coloring and decoloring have been becoming apparent.

[0005] Thus, an object of the present disclosure is to provide a dimming device having a configuration and a structure capable of effectively suppressing a coloring phenomenon and a bubble occurrence phenomenon, an image display device including a relevant dimming device, and a display device including a relevant image display device.

Solutions to Problems

[0006] A dimming device according to a first aspect or a second aspect of the present disclosure for achieving the object mentioned above includes:

[0007] a first substrate;

[0008] a second substrate that is provided facing the first substrate and to which external light enters;* and*

[0009] a light emitting stacked body provided between the first substrate and the second substrate,

[0010] in which the light emitting stacked body includes a first electrode, a dimming layer, and a second electrode stacked from the side of the first substrate,* and*

[0011] the dimming layer has a stacked structure of a reduction coloring layer, an electrolyte layer, and an oxidation coloring layer.

[0012] Then, in the dimming device according to the first aspect of the present disclosure, when the number of atoms of a metal contributing to reduction reaction in a compound contained in the reduction coloring layer is denoted by [Re] and the number of atoms of a metal contributing to oxidation reaction in a compound contained in the oxidation coloring layer is denoted by [Ox], the value of [Re]/[Ox] is within a prescribed range; further, in the dimming device according to the second aspect of the present disclosure, when the thickness of the reduction coloring layer is denoted by T.sub.Re and the thickness of the oxidation coloring layer is denoted by T.sub.Ox the value of T.sub.Re/T.sub.Ox is within a prescribed range.

[0013] An image display device according to the first aspect or the second aspect of the present disclosure for achieving the above object includes:

[0014] an image forming device;

[0015] an optical device having a virtual image forming region where a virtual image is formed on the basis of light emitted from the image forming device;* and*

[0016] a dimming device for adjusting the amount of light incident from outside, disposed to face at least the virtual image forming region,

[0017] in which the dimming device includes the dimming device according to the first aspect or the second aspect of the present disclosure above.

[0018] A display device according to the first aspect or the second aspect of the present disclosure for achieving the above object includes:

[0019] a frame to be mounted on a head of an observer;* and*

[0020] an image display device attached to the frame,

[0021]* in which the image display device includes*

[0022] an image forming device,

[0023] an optical device having a virtual image forming region where a virtual image is formed on the basis of light emitted from the image forming device,* and*

[0024] a dimming device for adjusting the amount of light incident from outside, disposed to face at least the virtual image forming region,* and*

[0025] the dimming device includes the dimming device according to the first aspect or the second aspect of the present disclosure above.

BRIEF DESCRIPTION OF DRAWINGS

[0026] FIGS. 1A and 1B are schematic cross-sectional views obtained by cutting a dimming device of Example 1 along the arrow A-A and the arrow B-B in FIG. 2A, respectively.

[0027] FIGS. 2A and 2B are a plan view of the first substrate and the like and a plan view of the second substrate and the like when viewing the dimming device of Example 1 from the light-incident side (above). FIG. 2C is a plan view of the first substrate and the like as viewed from the light-incident side (above) in a modified example of the dimming device of Example 1.

[0028] FIGS. 3A and 3B are a schematic cross-sectional view obtained by cutting a part of an image display device of Example 1 along an XZ plane and a schematic view of the dimming device of Example 1 as viewed from the front.

[0029] FIG. 4A is a schematic cross-sectional view obtained by cutting a part of the image display device of Example 1 along the arrow B-B in FIG. 3B (that is, cutting along a YZ plane). FIG. 4B is a schematic view of the display device of Example 1 as viewed from the side.

[0030] FIG. 5 is a conceptual diagram of the image display device of Example 1.

[0031] FIG. 6 is a schematic cross-sectional view illustrating a part of a reflection type volume hologram diffraction grating in an enlarged manner.

[0032] FIG. 7 is a schematic view of the display device of Example 1 as viewed from above.

[0033] FIG. 8 is a schematic view of the display device of Example 1 as viewed from the front.

[0034] FIGS. 9A and 9B are, respectively, a schematic cross-sectional view similar to a view obtained by cutting a dimming device of Example 2 along the arrow A-A in FIG. 2A, and a plan view of a first substrate and the like of the dimming device of Example 2 as viewed from the light-incident side (above).

[0035] FIGS. 10A and 10B are, respectively, a schematic cross-sectional view similar to a view obtained by cutting a dimming device of Example 3 along the arrow A-A in FIG. 2A, and a plan view of the first substrate and the like of the dimming device of Example 3 as viewed from the light-incident side (above).

[0036] FIG. 11 is a schematic cross-sectional view similar to a view obtained by cutting a dimming device of Example 4 along the arrow A-A in FIG. 2A.

[0037] FIGS. 12A and 12B are, respectively, a schematic cross-sectional view similar to a view obtained by cutting a dimming device of Example 5 along the arrow B-B in FIG. 2A, and a plan view of a second electrode and the like as viewed from the light-incident side (above).

[0038] FIGS. 13A and 13B are, respectively, a schematic cross-sectional view similar to a view obtained by cutting the dimming device of Example 5 along the arrow B-B in FIG. 2A, and a plan view of a first electrode and the like as viewed from the opposite side of the light-incident side (below).

[0039] FIG. 14 is a schematic cross-sectional view similar to a view obtained by cutting a different modified example of the dimming device of Example 5 along the arrow B-B in FIG. 2A.

[0040] FIGS. 15A and 15B are schematic cross-sectional views similar to views obtained by cutting a dimming device of Example 6 along the arrow A-A and the arrow B-B in FIG. 2A, respectively.

[0041] FIGS. 16A and 16B are schematic cross-sectional views similar to views obtained by cutting a modified example of the dimming device of Example 6 along the arrow A-A and the arrow B-B in FIG. 2A, respectively.

[0042] FIG. 17 is a conceptual diagram of an image display device of Example 7.

[0043] FIG. 18 is a conceptual diagram of an image display device of Example 8 (modified example of Example 1).

[0044] FIG. 19 is a conceptual diagram of the image display device of Example 8 (modified example of Example 7).

[0045] FIG. 20 is a conceptual diagram of an image display device in a display device of Example 9.

[0046] FIG. 21A is a schematic view of a display device of Example 10 as viewed from above. FIG. 21B is a schematic diagram of a circuit for controlling an illuminance sensor.

[0047] FIG. 22A is a schematic view of a display device of Example 11 as viewed from above. FIG. 22B is a schematic diagram of a circuit for controlling an illuminance sensor.

[0048] FIG. 23 is a schematic view of a display device of Example 12 as viewed from above.

[0049] FIG. 24 is a schematic front view of an optical device and a dimming device in the display device of Example 12 illustrated in FIG. 23.

[0050] FIG. 25 is a schematic view of a different display device of Example 12 as viewed from above.

[0051] FIG. 26 is a conceptual diagram of an image display device of Example 13.

[0052] FIG. 27 is a conceptual diagram of an image display device of Example 13.

[0053] FIG. 28 is a conceptual diagram for explaining an optical system in a modified example of the image display device of Example 13.

[0054] FIGS. 29A and 29B are schematic views of an optical device in a display device of Example 14 as viewed from above.

[0055] FIGS. 30A and 30B are schematic views of an optical device in a modified example of the display device of Example 14 as viewed from above and as viewed from a side, respectively.

[0056] FIG. 31 is a schematic cross-sectional view of the dimming device of Example 15.

[0057] FIG. 32 is a schematic view illustrating a dimming device having an elliptical outward shape.

[0058] FIGS. 33A and 33B are schematic cross-sectional views similar to views obtained by cutting a modified example of the dimming device of Example 1 along the arrow A-A in FIG. 2A.

[0059] FIG. 34 is a schematic front view of a modified example of a dimming device.

[0060] FIG. 35 is a conceptual diagram of an optical device in still another modified example of a display device of Example 1.

[0061] FIG. 36 is a graph showing results of evaluation of a coloring phenomenon and a bubble occurrence phenomenon of a dimming device in a display device of Example 1.

MODE FOR CARRYING OUT THE INVENTION

[0062] Hereinafter, the present disclosure will be described on the basis of Examples with reference to the drawings, but the present disclosure is not limited to the Examples, and the various numerical values and materials in the Examples are for illustrative purposes.

[0063] The description will proceed in the following order.

[0064] 1. General description of dimming device, image display device, and display device according to first and second aspects of the present disclosure.

[0065] 2. Example 1 (dimming device, image display device, and display device according to first aspect and second aspect of the present disclosure, and optical device with structure 1-B/image forming device with first configuration)

[0066] 3. Example 2 (modification of Example 1)

[0067] 4. Example 3 (different modification of Example 1)

[0068] 5. Example 4 (modification of Examples 1 to 3)

[0069] 6. Example 5 (modification of Examples 1 to 4)

[0070] 7. Example 6 (modification of Examples 1 to 5)

[0071] 8. Example 7 (modification of Examples 1 to 6, optical device with structure 1-B/image forming device with second configuration)

[0072] 9. Example 8 (modification of Examples 1 to 7, optical device with structure 1-A/image forming device with first or second configuration)

[0073] 10. Example 9 (modification of Examples 7 and 8, optical device with structure 2/image forming device with second configuration)

[0074] 11. Example 10 (modification of Examples 1 to 9)

[0075] 12. Example 11 (modification of Examples 1 to 9)

[0076] 13. Example 12 (modification of Examples 1 to 11)

[0077] 14. Example 13 (modification of Example 7)

[0078] 15. Example 14 (modification of Example 9)

[0079] 16. Example 15 (application to window of dimming device)

[0080] 17.* Others*

[0081] <General Description of Dimming Devices, Image Display Devices, and Display Devices According to First Aspect and Second Aspect of Present Disclosure>

[0082] A dimming device according to the first aspect of the present disclosure, a dimming device included in an image display device according to the first aspect of the present disclosure, and a dimming device included in a display device according to the first aspect of the present disclosure may be hereinafter collectively referred to as “a dimming device or the like according to the first aspect of the present disclosure”. Further, a dimming device according to the second aspect of the present disclosure, a dimming device included in an image display device according to the second aspect of the present disclosure, and a dimming device included in a display device according to the second aspect of the present disclosure may be hereinafter collectively referred to as “a dimming device or the like according to the second aspect of the present disclosure”.

[0083] In the dimming device or the like according to the first aspect of the present disclosure,* it is desirable that*

1.ltoreq.[Re]/[Ox].ltoreq.6.5,

* preferably*

1.ltoreq.[Re]/[Ox].ltoreq.5.5,* and*

* more preferably*

[Re]/[Ox].ltoreq.4.5

[0084] be satisfied.

[0085] The number of atoms [Re] of the metal contributing to reduction reaction in the compound contained in the reduction coloring layer is a value obtained by dividing the mass per unit area of the metal contained in the reduction coloring layer by the atomic weight of the metal, and the number of atoms [Ox] of the metal contributing to oxidation reaction in the compound contained in the oxidation coloring layer is a value obtained by dividing the mass per unit area of the metal contained in the oxidation coloring layer by the atomic weight of the metal.* The mass per unit area of the reduction coloring layer can be found by*

the mass per unit area of the metal contained in the reduction coloring layer=(the density of the reduction coloring layer).times.(the thickness of the reduction coloring layer).times..alpha..sub.Re,

* and*

[0086]* the mass per unit area of the oxidation coloring layer can be found by*

the mass per unit area of the metal contained in the oxidation coloring layer=(the density of the oxidation coloring layer).times.(the thickness of the oxidation coloring layer).times..alpha..sub.OXe.

Here,

[0087] .alpha..sub.Re=(the atomic weight of the metal contributing to reduction reaction)/(the atomic weight of the compound contained in the reduction coloring layer),

* and*

.alpha..sub.Ox=(the atomic weight of the metal contributing to oxidation reaction)/(the atomic weight of the compound contained in the oxidation coloring layer).

[0088] The density of the reduction coloring layer or the oxidation coloring layer is, as described later, the density when the reduction coloring layer or the oxidation coloring layer is measured by the X-ray reflectivity method (the XRR method). The reduction coloring layer and the oxidation coloring layer are often required to be formed as films at a temperature of approximately room temperature, and are therefore likely to be low-density (coarse) layers with low crystallinity. The metal atoms contained in the oxidation coloring layer and the reduction coloring layer can be identified on the basis of, for example, the X-ray photoelectron spectroscopy method (the XPS method or the ESCA method).

[0089] Further, in the dimming device or the like according to the second aspect of the present disclosure,* it is desirable that*

1.0.ltoreq.T.sub.Re/T.sub.Ox.ltoreq.4.5,

* preferably*

1.0.ltoreq.T.sub.Re/T.sub.Ox.ltoreq.3.8,* and*

* more preferably*

1.0.ltoreq.T.sub.Re/T.sub.Ox.ltoreq.3.3

[0090] be satisfied.

[0091] Alternatively, in the dimming device according to the second aspect of the present disclosure, a form in which, when the volume relative density of the reduction coloring layer is denoted by LD.sub.Re and the volume relative density of the oxidation coloring layer is denoted by LD.sub.Ox, the value of (T.sub.Re.times.LD.sub.Re.times..alpha..sub.Re)/(T.sub.Ox.times.LD.sub.OX- .times..alpha..sub.Ox) is within a prescribed range is possible. Then, in this case,* it is desirable that*

1.0.ltoreq.(T.sub.Re.times.LD.sub.Re.times..alpha..sub.Re)/(T.sub.Ox.tim- es.LD.sub.Ox.times..alpha..sub.Ox).ltoreq.4.6,

* preferably*

1.0.ltoreq.(T.sub.Re.times.LD.sub.Re.times..alpha..sub.Re)/(T.sub.Ox.tim- es.LD.sub.Ox.times..alpha..sub.Ox).ltoreq.3.8,* and*

* more preferably*

1.0.ltoreq.(T.sub.Re.times.LD.sub.Re.times..alpha..sub.Re)/(T.sub.Ox.tim- es.LD.sub.Ox.times..alpha..sub.Ox).ltoreq.3.3

[0092] be satisfied. The “volume relative density” is a value obtained by a method in which the density of the reduction coloring layer or the oxidation coloring layer when the reduction coloring layer or the oxidation coloring layer is measured by the X-ray reflectivity method (the XRR method) is divided by the density in a case where the compound contained in the reduction coloring layer or the oxidation coloring layer is a perfect crystal.

[0093] In the dimming device or the like according to the first aspect or the second aspect of the present disclosure including various preferred forms mentioned above, a form in which the reduction coloring layer contains tungsten oxide (WO.sub.3), the electrolyte layer contains tantalum oxide (Ta.sub.2O.sub.5), and the oxidation coloring layer contains iridium atoms is desirable. As a material contained in the oxidation coloring layer containing iridium atoms, iridium oxide (IrO.sub.x)-based materials, specifically iridium oxide (IrO.sub.x) and iridium tin oxide (Ir.sub.ySn.sub.1-yO.sub.x), may be given. However, the reduction coloring layer and the oxidation coloring layer are not limited to these; as a material contained in the reduction coloring layer, further inorganic materials such as molybdenum oxide (MoO.sub.3) and vanadium oxide (V.sub.2O.sub.5), and organic materials such as viologen derivatives, polythiophene derivatives, and Prussian blue derivatives may be given; as a material contained in the oxidation coloring layer, further inorganic materials such as rhodium oxide (RhO.sub.x), nickel oxide (NiO.sub.x), chromium oxide (CrO.sub.x), zirconium oxide (ZrO.sub.x), zirconium phosphate, nickel hydroxide, and copper chloride, metal complexes (Prussian blue complexes and ruthenium purple complexes), iron pentacyanocarbonylferrate, and organic materials such as amine derivatives, phenazine, and viologen derivatives may be given. Further, as the electrolyte layer, propylene carbonate, ion liquids, and ion polymers may be given as well.

[0094] Furthermore, in the dimming device or the like according to the first aspect or the second aspect of the present disclosure including various preferred forms mentioned above, a form in which a moisture-retaining member is provided at least between the second electrode and the second substrate is possible; in this case, a form in which an end surface of the moisture-retaining member is exposed to the outside is possible. Note that a form in which at least part of an end section (a side surface) of the dimming device includes a sealing member and a moisture-retaining member from the side of the first substrate (that is, a form in which at least part of an end section of the dimming device has a stacked structure of a sealing member and a moisture-retaining member extending portion extending from a moisture-retaining member from the side of the first substrate) is possible.

[0095] Further, a form in which the second electrode is formed extending over from a dimming layer to a first substrate, and separated from a first electrode, and the moisture-retaining member covers at least the second electrode and the dimming layer is possible.

[0096] The resin forming the moisture-retaining member may be an acrylic resin, a silicone resin, or an urethane resin. Alternatively, the moisture-retaining member may contain an ultraviolet-curing resin. Alternatively, the moisture-retaining member may contain a material called an optical clear adhesive (OCA). Alternatively, as a material contained in the moisture-retaining member, at least one kind of material selected from the group including an epoxy-based resin, a polyvinyl-based resin such as polyvinyl alcohol or polyvinyl butyral, a moisture-containing gel, and a porous material may be given. As the moisture-containing gel, a mixture of sodium polyacrylate and polyethylene glycol having a dendron group at a terminal may be given as an example; as the porous material, silica that is surface-modified with an organic silane compound, and the like may be given. Note that “the moisture-retaining member” may be reworded as a proton supply member, a transparent sticky member capable of retaining moisture, or a transparent sealing member capable of retaining moisture. Although dependent on the form of the moisture-retaining member, in the case where the moisture-retaining member is sheet-like, for example, the second substrate and the second electrode or the second substrate and the sealing member can be stuck to each other through the moisture-retaining member, or a thermoplastic ultraviolet-curing moisture-retaining member can be used. Alternatively, in the case where the moisture-retaining member is a liquid, it is sufficient to apply the moisture-retaining member throughout from the second electrode to the sealing member, and after pre-curing as necessary, overlay the second substrate onto the moisture-retaining member while applying pressure as necessary, and cure the moisture-retaining member with ultraviolet rays. Alternatively, although dependent on the material to use, the moisture-retaining member may also be stuck throughout from the second electrode to the sealing member on the basis of a method such as heat laminating.

[0097] The sealing member functions as a moisture barrier layer, but part of the sealing member may be formed by an auxiliary electrode. In this case, the auxiliary electrode may include a first auxiliary electrode formed on the first electrode and a second auxiliary electrode formed on the second electrode and separated from the first auxiliary electrode. In this way, by providing the auxiliary electrodes, appropriate voltages can be applied easily to the first electrode and the second electrode, and the occurrence of a voltage drop in the first electrode or the second electrode can be suppressed, thereby reducing unevenness when the dimming device is colored. The similar applies hereinafter. When the length of the auxiliary electrode as a whole is “1”, the length of the first auxiliary electrode is preferably less than 0.5, and the length of the second auxiliary electrode is preferably less than 0.5. The similar applies hereinafter.

[0098] Alternatively, the sealing member may contain a resin. In this case, the Young’s modulus of the resin contained in the sealing member may be 1.times.10.sup.7 Pa or less, and furthermore, in these cases, the auxiliary electrode may be provided on an inner side of a part of the sealing member. Here, the auxiliary electrode may include a first auxiliary electrode formed on top of the first electrode and a second auxiliary electrode formed on top of the second electrode and separated from the first auxiliary electrode. As a resin contained in the sealing member, various resins such as a thermosetting type, a photocuring type, a moisture curing type, and an anaerobic curing type may be given, such as one kind of resin selected from the group including an acrylic-based resin, an urethane-based resin, a silicone-based resin, a fluorine-based resin, a vinyl acetate-based resin, an ene-thiol-based resin, a modified polymer resin, a polyimide-based resin, and an epoxy-based resin. In the case where the sealing member contains a resin, inorganic filler such as silica and alumina may also be added to the resin.

[0099] Alternatively, the sealing member may include a protruding portion provided in an edge portion of the first substrate. In this case, the auxiliary electrode may be provided on an inner side of a part of the sealing member. Here, the auxiliary electrode may include a first auxiliary electrode formed on top of the first electrode and a second auxiliary electrode formed on top of the second electrode and separated from the first auxiliary electrode. The protruding portion in the edge portion of the first substrate may be formed by hot-pressing the edge portion of the first substrate using a hot press, and may also be formed by any of various physical vapor deposition methods (PVD methods) or chemical vapor deposition methods (CVD methods), and printing methods, for example.

[0100] Furthermore, the cross-sectional shape of the sealing member may become narrower as approaching the second substrate. By causing the cross-sectional shape of the sealing member to have such a shape, when the moisture-retaining member is disposed on top of at least the second electrode and the moisture-retaining member extending portion that extends from the moisture-retaining member is disposed on top of the sealing member, the occurrence of problems such as bubbles getting under the moisture-retaining member may be avoided. Such a cross-sectional shape of the sealing member may be formed on the basis of any of various methods, such as molding of the sealing member based on a printing method or molding of the sealing member based on a sputtering method using a metal mask, for example.

[0101] Furthermore, the Young’s modulus of the material (specifically, the resin) forming the moisture-retaining member is desirably 1.times.10.sup.6 Pa or less. With this arrangement, various differences in level occurring inside the dimming device can be absorbed, and inconsistencies in the thickness of the moisture-retaining member in a central portion of the dimming device and inconsistencies in the thickness of the moisture-retaining member extending portion can be reduced (in other words, a uniform overall distance between the first substrate and the second substrate may be attained), thereby preventing degraded visibility. Specifically, when looking out at the external world through the dimmning device, the occurrence of distortions or discrepancies in the image of the external world can be suppressed.

[0102] The moisture-retaining member is disposed on top of at least the second electrode and the moisture-retaining member extending portion that extends from the moisture-retaining member is disposed on top of the sealing member. Specifically, for example, it is sufficient to bond or stick the moisture-retaining member to the second electrode, and bond or stick the moisture-retaining member extending portion to the sealing member. Also, the second substrate is disposed on top of the moisture-retaining member and the moisture-retaining member extending portion. Specifically, for example, it is sufficient to bond or stick the second substrate to the moisture-retaining member and the moisture-retaining member extending portion.

[0103] Furthermore, in the dimming device or the like according to the first aspect or the second aspect of the present disclosure including various preferred forms, each of the first substrate and the second substrate preferably contains a plastic material. That is, a form in which each of the first substrate and the second substrate includes a plastic substrate, a plastic sheet, or a plastic film is possible. If each of the first substrate and the second substrate contains a plastic material, there are many cases where uniform film formation of each layer included in the dimming layer is difficult and variation is likely to occur in film thickness distribution and roughness, due to warpage and smoothness of the first substrate and the second substrate; however, the value of [Re]/[Ox] has been prescribed, or the value of T.sub.Re/T.sub.Ox has been prescribed; thus, in a case where each of the first substrate and the second substrate contains a plastic material, there is no problem even if the problems mentioned above occur.

[0104] Here, examples of the plastic include polyethylene terephthalate, polyethylene naphthalate, polycarbonate, a cellulose ester such as cellulose acetate, a fluorocarbon polymer such as polyvinylidene fluoride or a copolymer of polytetrafluoroethylene and hexafluoropropylene, a polyether such as polyoxymethylene, polyacetal, polystyrene, a polyolefin such as polyethylene, polypropylene, or a methylpentene polymer, a polyimide such as polyamideimide or polyetherimide, polyamide, polyether sulfone, polyphenylene sulfide, polyvinylidene fluoride, tetraacetyl cellulose, brominated phenoxy, polyarylate, polysulfone, and the like. Note that if necessary, as described later, it is only required to dispose the inorganic film on the second substrate and by doing this, rigidity can be imparted to the second substrate, thereby making strain occur less readily in the second substrate when assembling a dimming device. Alternatively, the first substrate and the second substrate may be constituted by a transparent glass substrate such as a soda-lime glass or a white plate glass.

[0105] Furthermore, in the dimming device or the like according to the first aspect or the second aspect of the present disclosure including the preferable form and configuration described above (hereinafter collectively referred to as the “dimming device or the like according to the present disclosure”), the dimming device can be curved. With this arrangement, the dimming device can be easily and reliably mounted to the image display device or the display device.

[0106] The second substrate also functions as a protective substrate, for example. The first substrate faces the optical device with or without a gap in between, or alternatively, doubles as the member forming the optical device (for example, a protective member provided in the optical device). On an outer face of the second substrate, a hard coat layer containing an organic/inorganic mixed layer or an anti-reflection film containing a fluorine resin may be formed.

[0107] Furthermore, in the dimming device or the like of the present disclosure including the preferable form and configuration described above, an inorganic film may be formed on the face of the second substrate that faces the moisture-retaining member. Here, the inorganic film contains an inorganic material such as aluminum oxide, silicon oxide, silicon nitride, or niobium oxide, for example. By forming the inorganic film, rigidity can be imparted to the second substrate, thereby making strain occur less readily in the second substrate. The inorganic film may be formed on the basis of PVD, CVD, laser ablation, or atomic layer deposition (ALD), for example.

[0108] The control of the light shielding ratio can be made on the basis of, for example, a simple matrix system. In other words,

[0109] the first electrode may include a plurality of band-shaped first electrode segments extending in a first direction,

[0110] the second electrode may include a plurality of band-shaped second electrode segments extending in a second direction different from the first direction,* and*

[0111] a light shielding ratio of a portion of the dimming device corresponding to overlap regions between the first electrode segments and the second electrode segments (minimum unit regions in which the light shielding ratio of the dimming device changes) may be controlled on the basis of control of voltages applied to the first electrode segments and the second electrode segments. The first direction and the second direction may be orthogonal to each other, for example. Alternatively, in order to control the light shielding ratios of the minimum unit regions in which the light shielding ratio of the dimming device changes, a thin film transistor (TFT) may be disposed in each of the minimum unit regions. In other words, the light shielding ratio may be controlled on the basis of an active matrix method. Alternatively, at least one of the first electrode or the second electrode may be a so-called solid electrode (electrode not patterned).

[0112] The first electrode may be patterned or does not have to be patterned. The second electrode may be patterned or does not have to be patterned. Examples of a material contained in the first electrode and the second electrode include a transparent conductive material. More specific examples thereof include an indium-tin composite oxide (indium tin oxide (ITO), including Sn-doped In.sub.2O.sub.3, crystalline ITO, and amorphous ITO), fluorine-doped SnO.sub.2 (FTO), F-doped In.sub.2O.sub.3 (IFO), antimony-doped SnO.sub.2 (ATO), SnO.sub.2, ZnO (including Al-doped ZnO and B-doped ZnO), indium-zinc composite oxide (indium zinc oxide (IZO)), a spinel type oxide, an oxide having a YbFe.sub.2O.sub.4 structure, and a conductive polymer such as polyaniline, polypyrrole, or polythiophene, and the like, but are not limited thereto. Furthermore, two or more kinds thereof can be used in combination. Alternatively, the first electrode and the second electrode in a thin line shape can be constituted by metal such as gold, silver, copper, aluminum, nickel, or titanium, or alloy. The auxiliary electrode can also be formed, for example, using metal such as gold, silver, copper, aluminum, nickel, titanium, or alloys thereof. Alternatively, the auxiliary electrode can be formed using silver paste or copper paste. The auxiliary electrode (first auxiliary electrode and second auxiliary electrode) is demanded to have a lower electrical resistance than the first electrode and the second electrode. The first electrode, the second electrode, and the auxiliary electrode (first auxiliary electrode and second auxiliary electrode) can be formed on the basis of various PVD methods such as a vacuum vapor deposition method or a sputtering method, various CVD methods, various kinds of coating, and various kinds of printing methods. Patterning of an electrode can be performed by any method such as an etching method, a lift-off method, or a method using various masks.

[0113] Furthermore, in the image display device of the present disclosure including the above-described preferable form and the display device of the present disclosure including the above-described preferable form,

[0114] the optical device may include:

[0115] (b-1) a light guide plate in which light incident from the image forming device is propagated by total reflection through the inside, and then the light is emitted toward an observer;

[0116] (b-2) first deflecting means for deflecting light incident on the light guide plate such that the light incident on the light guide plate is totally reflected inside the light guide plate;* and*

[0117] (b-3) second deflecting means for deflecting light propagated by total reflection through the inside of the light guide plate and emitting the light from the light guide plate,* and*

[0118] the second deflecting means may form a virtual image forming region of the optical device. Such an optical device is referred to as “optical device with first structure” for convenience. Note that the term “total reflection” means total internal reflection or total reflection inside the light guide plate. In some cases, the second deflecting means (virtual image forming region) is positioned inside the projected image of the dimming device, while in other cases, the dimming device is positioned inside the projected image of the second deflecting means (virtual image forming region).

[0119] A region in which a high light shielding ratio is set in the dimming device may be a whole region of the dimming device or a partial region of the dimming device. In other words, the light shielding ratio of a region of the dimming device facing a region of the second deflecting means (for example, a partial region of the second deflecting means) where a virtual image is actually formed may be controlled. In other words, if a virtual image is formed in a part of the virtual image forming region on the basis of light emitted from the image forming device, the dimming device may perform control such that the light shielding ratio of a virtual image projection region (region of the dimming device corresponding to the virtual image forming region in the optical device) of the dimming device including a projected image of a virtual image on the dimming device is higher than the light shielding ratio of another region of the dimming device. Note that the position of the virtual image projection region does not have to be fixed in the dimming device but may vary depending on the formation position of a virtual image. Furthermore, the number of the virtual image projection regions may also vary depending on the number of virtual images (the number of a series of virtual image groups, the number of blocked virtual image groups, or the like).

[0120] During operation of the dimming device, if the light shielding ratio of the virtual image projection region of the dimming device including a projected image of a virtual image on the dimming device is assumed to be “1”, the light shielding ratio of another region of the dimming device may be, for example, 0.95 or less. Alternatively, the light shielding ratio of another region of the dimming device may be, for example, 30% or less. Meanwhile, during operation of the dimming device, the light shielding ratio of the virtual image projection region of the dimming device may be 35% to 99%, for example, 80%. As described above, the light shielding ratio of the virtual image projection region may be constant or may vary depending on illuminance of an environment in which the display device is placed.

[0121] In the display device of the present disclosure including the various preferable forms described above (hereinafter collectively referred to as the “display device or the like of the present disclosure” in some cases), the frame may include a front portion disposed in front of an observer, two temple portions rotatably attached to both ends of the front portion via hinges, and a nose pad. The dimming device may be disposed on the front portion, and in this case, the optical device may be attached to the dimming device. Alternatively, the optical device may be attached to the front portion, and in this case, the dimming device may be attached to the optical device. Furthermore, in these cases, the front portion may have a rim portion, and the dimming device may be fitted in the rim portion, or the optical device may be fitted in the rim portion, and in this case, the optical device may be fixed to the rim portion by using an adhesive that allows water vapor to permeate therethrough. Alternatively, a form in which the space between the dimming device and the optical device communicates with the outside is possible. In the display device or the like of the present disclosure, from an observer side, the optical device and the dimming device may be disposed in this order, or the dimming device and the optical device may be disposed in this order.

[0122] Examples of an adhesive that allows water vapor to permeate therethrough include an adhesive containing a nonpolar material such as a silicone type, an ethylene vinyl alcohol type copolymer, or a styrene type butadiene, which have a high water vapor diffusion property, as a main component, and examples of the moisture permeability value of the adhesive include 2.times.10 g/m.sup.2day to 1.1.times.10.sup.3 g/m.sup.2day. Note that the moisture permeability can be measured according to JIS K7129:2008, and a test piece of 50 mm.times.50 mm is subjected to a test at a test temperature 25.degree. C..+-.0.5.degree. C. and a relative humidity of 90.+-.2%. The measurement uses a dry/wet sensor.

[0123] In the display device or the like of the present disclosure, the light shielding ratio may change gradually (that is, may change continuously), may change stepwise depending on the disposition state and shapes of electrodes, or may change continuously or stepwise from a constant value. In other words, the dimming device may be in a state with color gradation, may be in a state in which a color changes stepwise, or may be in a state in which a color changes continuously or stepwise from a state with a constant color. The light shielding ratio can be controlled by voltages applied to the first electrode and the second electrode. A potential difference between the first electrode and the second electrode may be controlled, or a voltage applied to the first electrode and a voltage applied to the second electrode may be independently controlled. In a case of adjusting the light shielding ratio, a test pattern may be displayed on the optical device.

[0124] The display device or the like of the present disclosure may further include an environmental illuminance measuring sensor for measuring the illuminance of an environment in which the display device is placed, and may control the light shielding ratio of the dimming device on the basis of a measurement result of the environmental illuminance measuring sensor. Alternatively, the display device or the like may further include an environmental illuminance measuring sensor for measuring the illuminance of an environment in which the display device is placed, and may control the brightness of an image formed by the image forming device on the basis of a measurement result of the environmental illuminance measuring sensor. These forms may be combined with each other.

[0125] Alternatively, the display device or the like may further include a transmitted light illuminance measuring sensor for measuring illuminance based on light which has passed through the dimming device from an external environment, and may control the light shielding ratio of the dimming device on the basis of a measurement result of the transmitted light illuminance measuring sensor. Alternatively, the display device or the like may further include a transmitted light illuminance measuring sensor for measuring illuminance based on light which has passed through the dimming device from an external environment, and may control the brightness of an image formed by the image forming device on the basis of a measurement result of the transmitted light illuminance measuring sensor. The transmitted light illuminance measuring sensor is desirably disposed closer to an observer side than the optical device. At least two transmitted light illuminance measuring sensors may be disposed, and illuminance based on light which has passed through a portion with a high light shielding ratio and illuminance based on light which has passed through a portion with a low light shielding ratio may be measured. These forms may be combined with each other. Furthermore, these forms may be combined with the above-described form in which control is performed on the basis of a measurement result of the environmental illuminance measuring sensor.

[0126] The illuminance sensor (environmental illuminance measuring sensor or transmitted light illuminance measuring sensor) only needs to be constituted by a well-known illuminance sensor, and only needs to be controlled on the basis of a well-known control circuit.

[0127] The maximum light transmittance of the dimming device may be 50% or more, and the minimum light transmittance of the dimming device may be 30% or less. An upper limit value of the maximum light transmittance of the dimming device may be 99%, and a lower limit value of the minimum light transmittance of the dimming device may be 1%. Here,

[0128]* there is a relationship of*

(light transmittance)=1-(light shielding ratio).

[0129] It is only required to attach a connector to the dimming device, and to electrically connect the dimming device to a control circuit (for example, included in a control device for controlling an image forming device) for controlling the light shielding ratio (light transmittance) of the dimming device via the connector and wiring.

[0130] In some cases, light passing through the dimming device may be colored in a desired color by the dimming device. In addition, in this case, a color in which light is colored by the dimming device may be variable or fixed. In the former case, for example, it is only required to laminate a dimming device for coloring light in red, a dimming device for coloring light in green, and a dimming device for coloring light in blue. Furthermore, in the latter case, a color in which light is colored by the dimming device is not limited, but may be blue or brown, for example.

[0131] Furthermore, in some cases, the dimming device may be detachably disposed. In order to detachably dispose the dimming device, for example, the dimming device may be attached, for example, to a frame using a screw manufactured from a transparent plastic. Alternatively, the dimming device may be attached to a frame by forming a groove in the frame and engaging the dimming device with the groove or by attaching a magnet to the frame. Alternatively, the dimming device may be fitted in a slide portion by forming the slide portion in a frame.

[0132] The optical device is a semi-transmission type (see-through type) device. Specifically, at least a portion of the optical device facing an eyeball (pupil) of an observer is made semi-transmissive (see-through), and an outside scene can be viewed through this portion of the optical device and the dimming device. The light shielding ratio can be controlled and adjusted manually by observation of the lightness of light which has passed through the dimming device and the optical device by an observer and operation of a switch, a button, a dial, a slider, a knob, or the like by the observer. Alternatively, the light shielding ratio can be controlled and adjusted on the basis of a measurement result of the above-described transmitted light illuminance measuring sensor for measuring illuminance based on light which has passed through the dimming device from an external environment. Specifically, control and adjustment of the light shielding ratio only need to be performed by controlling voltages applied to the first electrode and the second electrode. At least two transmitted light illuminance measuring sensors may be disposed, and illuminance based on light which has passed through a portion with a high light shielding ratio and illuminance based on light which has passed through a portion with a low light shielding ratio may be measured. The display device may include one image display device (single eye type) or two image display devices (binocular type). In a case where the display device includes two image display devices, by adjusting voltages applied to the first electrode and the second electrode in each of one dimming device and the other dimming device, the light shielding ratios of one dimming device and the other dimming device can be equalized. The light shielding ratios in one dimming device and the other dimming device can be controlled, for example, on the basis of a measurement result of the above-described transmitted light illuminance measuring sensor for measuring illuminance based on light which has passed through the dimming device from an external environment, or can be controlled and adjusted manually by observation of the lightness of light which has passed through one dimming device and the optical device and the lightness of light which has passed through the other dimming device and the optical device by an observer and operation of a switch, a button, a dial, a slider, a knob, or the like by the observer. In a case of adjusting the light shielding ratio, a test pattern may be displayed on the optical device.

[0133] Here, the term “semi-transmissive” may be used, and the term “semi-transmissive” does not mean that a half (50%) of incident light is transmitted or reflected, but means that a part of incident light is transmitted and the remaining light is reflected.

[0134] In the optical device with first structure, as described above, the first deflecting means may reflect light incident on the light guide plate, and the second deflecting means may transmit and reflect light propagated by total reflection through the inside of the light guide plate (a plurality of times). In addition, in this case, the first deflecting means may function as a reflecting mirror, and the second deflecting means may function as a semi-transmissive mirror. Such an optical device with first structure is referred to as “optical device with structure 1-A” for convenience.

[0135] In such an optical device with structure 1-A, the first deflecting means may be constituted by, for example, a light reflecting film (a kind of mirror) that is constituted by metal including alloy and reflects light incident on the light guide plate, or a diffraction grating (for example, a hologram diffraction grating film) that diffracts light incident on the light guide plate. Alternatively, the first deflecting means may be constituted by a multilayer laminated structure in which many dielectric laminated films are laminated, a half mirror, or a polarization beam splitter, for example. Furthermore, the second deflecting means may be constituted by a multilayer laminated structure in which many dielectric laminated films are laminated, a half mirror, a polarization beam splitter, or a hologram diffraction grating film. In addition, the first deflecting means and the second deflecting means are disposed inside the light guide plate (incorporated in the light guide plate). In the first deflecting means, parallel light incident on the light guide plate is reflected or diffracted so as to be totally reflected inside the light guide plate. Meanwhile, in the second deflecting means, parallel light propagated by total reflection through the inside of the light guide plate is reflected or diffracted (a plurality of times), and is emitted from the light guide plate in the state of parallel light.

[0136] Alternatively, the first deflecting means may diffract and reflect light incident on the light guide plate, and the second deflecting means may diffract and reflect light propagated by total reflection through the inside of the light guide plate. In addition, in this case, the first deflecting means and the second deflecting means may be constituted by diffraction grating elements. Furthermore, the diffraction grating elements may be constituted by reflection type diffraction grating elements or transmission type diffraction grating elements. Alternatively, one of the diffraction grating elements may be constituted by a reflection type diffraction grating element, and the other of the diffraction grating elements may be constituted by a transmission type diffraction grating element. Examples of the reflection type diffraction grating element include a reflection type volume hologram diffraction grating. The reflection type volume hologram diffraction grating means a hologram diffraction grating for diffracting and reflecting only +1st order diffracted light. A first deflecting means constituted by a hologram diffraction grating may be referred to as a “first diffraction grating member” for convenience, and second deflecting means constituted by a hologram diffraction grating may be referred to as a “second diffraction grating member” for convenience. Furthermore, such an optical device with first structure is referred to as “optical device with structure 1-B” for convenience.

[0137] In the optical device with structure 1-B, third deflecting means that light emitted from the first deflecting means is incident on may be provided. Then, light emitted from the third deflecting means is incident on the second deflecting means. Here, each of the first deflecting member, the second deflecting member, and the third deflecting member includes a volume hologram diffraction grating; when a wave number vector obtained when the wave number vector possessed by the first deflecting member is projected on the light guide plate is denoted by k.sup.v.sub.1, a wave number vector obtained when the wave number vector possessed by the second deflecting member is projected on the light guide plate is denoted by k.sup.v.sub.2, and a wave number vector obtained when the wave number vector possessed by the third deflecting member is projected on the light guide plate is denoted by k.sup.v.sub.3,* it is preferable that*

k.sup.v.sub.1+k.sup.v.sub.2+k.sup.v.sub.3=0

be satisfied.

[0138] The image display device in the display device or the like of the present disclosure can display an image of a single color (for example, green). In addition, in this case, for example, by dividing an angle of view into two (more specifically, for example, by dividing the angle of view into two equal parts) for example, the first deflecting means may be formed by laminating two diffraction grating members corresponding to groups of the angle of view divided into two. Alternatively, in a case where a color image is displayed, the first diffraction grating member or the second diffraction grating member may be formed by laminating P layers of diffraction grating layers each including a hologram diffraction grating so as to correspond to diffraction reflection of P types of light beams having different P types (for example, P=3, and three types of red, green, and blue) of wavelength bands (or wavelengths). In each diffraction grating layer, an interference fringe corresponding to one type of wavelength band (or wavelength) is formed. Alternatively, the first diffraction grating member or the second diffraction grating member including one diffraction grating layer may have P types of interference fringes formed so as to correspond to diffraction reflection of P types of light beams having different P types of wavelength bands (or wavelengths). Alternatively, for example, a diffraction grating member including a diffraction grating layer including a hologram diffraction grating for diffracting and reflecting light having a red wavelength band (or wavelength) may be disposed on a first light guide plate, a diffraction grating member including a diffraction grating layer including a hologram diffraction grating for diffracting and reflecting light having a green wavelength band (or wavelength) may be disposed on a second light guide plate, a diffraction grating member including a diffraction grating layer including a hologram diffraction grating for diffracting and reflecting light having a blue wavelength band (or wavelength) may be disposed on a third light guide plate, and the first light guide plate, the second light guide plate, and the third light guide plate may be stacked with a gap therebetween. Alternatively, the first diffraction grating member or the second diffraction grating member may be constituted by dividing an angle of view, for example, into three equal parts and laminating diffraction grating layers corresponding to the divided angles of view. In addition, by adopting these configurations, it is possible to increase diffraction efficiency, to increase a diffraction reception angle, and to optimize a diffraction angle when light having each wavelength band (or wavelength) is diffracted and reflected by the first diffraction grating member or the second diffraction grating member. A protective member is preferably disposed such that an observer does not touch a hologram diffraction grating.

[0139] Examples of a material constituting the first diffraction grating member and the second diffraction grating member include a photopolymer material. A constituent material and a basic structure of each of the first diffraction grating member and the second diffraction grating member including a hologram diffraction grating only need to be the same as those of a conventional hologram diffraction grating. Interference fringes are formed from the inside to a surface of a diffraction grating member. A method for forming the interference fringes themselves only needs to be the same as a conventional formation method. Specifically, for example, by irradiating a member (for example, a photopolymer member) constituting a diffraction grating member with object light from a first predetermined direction on one side, and at the same time, by irradiating the member constituting a diffraction grating member with reference light from a second predetermined direction on the other side, it is only required to record an interference fringe formed by the object light and the reference light inside the member constituting a diffraction grating member. By appropriately selecting the first predetermined direction, the second predetermined direction, and the wavelengths of the object light and the reference light, it is possible to obtain a desired pitch of an interference fringe on a surface of a diffraction grating member and a desired inclination angle (slant angle) of the interference fringe. The inclination angle of an interference fringe means an angle formed by a surface of a diffraction grating member (or diffraction grating layer) and the interference fringe. In a case where the first diffraction grating member and the second diffraction grating member are each constituted by a laminated structure of P layers of diffraction grating layers each including a hologram diffraction grating, such a lamination of diffraction grating layers only needs to be performed by manufacturing each of P layers of diffraction grating layers separately, and then laminating (bonding) the P layers of diffraction grating layers using, for example, an ultraviolet curable adhesive. Furthermore, by manufacturing a single diffraction grating layer using an adhesive photopolymer material and then sequentially sticking an adhesive photopolymer material onto the diffraction grating layer to manufacture a diffraction grating layer, the P layers of diffraction grating layers may be manufactured. By irradiating the manufactured diffraction grating layer with an energy ray, if necessary, a monomer remaining in the photopolymer material without being polymerized when the diffraction grating layer is irradiated with the object light and the reference light may be polymerized and fixed. Furthermore, if necessary, a heat treatment may be performed for stabilization.

[0140] Alternatively, in the image display device in the display device or the like of the present disclosure, the optical device may be constituted by a semi-transmissive mirror into which light emitted from the image forming device is incident and from which the light is emitted toward a pupil of an observer or may be constituted by a polarization beam splitter (PBS). The semi-transmissive mirror or the polarization beam splitter forms a virtual image forming region of the optical device. Light emitted from the image forming device may be propagated in air to be incident on the semi-transmissive mirror or the polarization beam splitter. For example, the light may be propagated through the inside of a transparent member such as a glass plate or a plastic plate (specifically, a member constituted by a similar material to a material constituting a light guide plate described later) to be incident on the semi-transmissive mirror or the polarization beam splitter. The semi-transmissive mirror or the polarization beam splitter may be attached to the image forming device via this transparent member or via a member different from this transparent member. Such an optical device is referred to as “optical device with second structure” for convenience. The semi-transmissive mirror may be constituted by the first deflecting means in the optical device with structure 1-A, for example, a light reflecting film (a kind of mirror) that is constituted by metal including alloy and reflects light, or a diffraction grating (for example, a hologram diffraction grating film). Alternatively, the optical device may be constituted by a prism on which light emitted from the image forming device is incident and from which the light is emitted toward a pupil of an observer.

[0141] In the image display device in the display device or the like of the present disclosure including the above-described various preferable forms and configurations, the image forming device may have a plurality of pixels arranged in a two-dimensional matrix. Such a configuration of the image forming device is referred to as “image forming device with first configuration” for convenience.

[0142] Examples of the image forming device with first configuration include: an image forming device including a reflection type spatial light modulator and a light source; an image forming device including a transmission type spatial light modulator and a light source; and an image forming device including a light emitting element such as an organic electro luminescence (EL), an inorganic EL, a light emitting diode (LED), or a semiconductor laser element. Among these devices, the image forming device (organic EL display device) including an organic EL light emitting element and the image forming device including a reflection type spatial light modulator and a light source are preferable. Examples of the spatial light modulator include a light valve, a transmission type or reflection type liquid crystal display device such as a liquid crystal on silicon (LCOS), and a digital micromirror device (DMD). Examples of the light source include a light emitting element. Furthermore, the reflection type spatial light modulator may include a liquid crystal display device and a polarization beam splitter for reflecting a part of light emitted from a light source to guide the light to the liquid crystal display device and transmitting a part of the light reflected by the liquid crystal display device to guide the light to an optical device (for example, light guide plate). Examples of the light emitting element constituting the light source include a red light emitting element, a green light emitting element, a blue light emitting element, and a white light emitting element. Alternatively, white light may be obtained by mixing colors of red light, green light, and blue light emitted from the red light emitting element, the green light emitting element, and the blue light emitting element using a light pipe and uniformizing brightness. Examples of the light emitting element include a semiconductor laser element, a solid state laser, and an LED. The number of pixels only needs to be determined on the basis of specifications required for the image display device, and examples of a specific value of the number of pixels include 320.times.240, 432.times.240, 640.times.480, 1024.times.768, 1920.times.1080, and the like. In the image forming device with first configuration, an aperture may be disposed at a position of a front focal point (focal point on the image forming device side) of a lens system (described later), and this aperture corresponds to an image emitting portion from which an image is emitted in the image forming device.

[0143] Alternatively, in the image display device in the display device or the like of the present disclosure including the above-described preferable forms and configurations, the image forming device may include a light source and scanning means for scanning light emitted from the light source to form an image. Such an image forming device is referred to as “image forming device with second configuration” for convenience.

[0144] Examples of the light source in the image forming device with second configuration include a light emitting element, and specific examples thereof include a red light emitting element, a green light emitting element, a blue light emitting element, and a white light emitting element. Alternatively, white light may be obtained by mixing colors of red light, green light, and blue light emitted from the red light emitting element, the green light emitting element, and the blue light emitting element using a light pipe and uniformizing brightness. Examples of the light emitting element include a semiconductor laser element, a solid state laser, and an LED. The number of pixels (virtual pixels) in the image forming device with second configuration only needs to be determined on the basis of specifications required for the image display device, and examples of a specific value of the number of pixels (virtual pixels) include 320.times.240, 432.times.240, 640.times.480, 1024.times.768, 1920.times.1080, and the like. Furthermore, in a case where a color image is to be displayed and in a case where the light source includes a red light emitting element, a green light emitting element, and a blue light emitting element, color synthesis is preferably performed using, for example, a cross prism. Examples of the scanning means include a micro electro mechanical systems (MEMS) mirror having a micro mirror rotatable in a two-dimensional direction and a galvanometer mirror, the mirrors horizontally and vertically scanning light emitted from the light source. In the image forming device with second configuration, a MEMS mirror or a galvanometer mirror may be disposed at a position of a front focal point (focal point on the image forming device side) of a lens system (described later), and the MEMS mirror or the galvanometer mirror corresponds to an image emitting portion from which an image is emitted in the image forming device.

[0145] In the image forming device with first configuration or the image forming device with second configuration in the image display device including the optical device with first structure, light converted into a plurality of parallel light beams by a lens system (an optical system for converting emitted light into parallel light) is incident on an optical device (for example, light guide plate). Such a requirement for obtaining parallel light is based on necessity of saving optical wavefront information when the light is incident on the optical device even after the light is emitted from the optical device via the first deflecting means and the second deflecting means. In order to generate a plurality of parallel light beams, specifically, as described above, for example, it is only required to locate a light emitting portion of the image forming device at a position (location) of a focal length in the lens system. The lens system has a function of converting position information of a pixel into angle information in the optical device. Examples of the lens system include an optical system having a positive optical power as a whole, such as a convex lens, a concave lens, a free curved surface prism, a hologram lens, or a combination thereof. A light shielding portion having an opening may be disposed between the lens system and the optical device in order to prevent undesired light emitted from the lens system from being incident on the optical device.

[0146] The light guide plate has two parallel surfaces (first surface and second surface) extending parallel to an axis (longitudinal direction or horizontal direction, corresponding to an X direction) of the light guide plate. The width direction (height direction or vertical direction) of the light guide plate corresponds to a Y direction. If a surface of the light guide plate on which light is incident is referred to as a light guide plate incident surface and a surface of the light guide plate from which light is emitted is referred to as a light guide plate emission surface, the first surface may constitute the light guide plate incident surface and the light guide plate emission surface, or the first surface may constitute the light guide plate incident surface and the second surface may constitute the light guide plate emission surface. The first deflecting means is disposed on the first surface or the second surface of the light guide plate, and the second deflecting means is disposed on the first surface or the second surface of the light guide plate. An interference fringe of a diffraction grating member extends substantially parallel to the Y direction. Examples of a material constituting the light guide plate include glass including an optical glass such as a quartz glass or BK7, a soda lime glass, and a white plate glass, and a plastic material (for example, PMMA, a polycarbonate resin, a laminated structure of a polycarbonate resin and an acrylic resin, an acrylic resin, a cycloolefin polymer, an amorphous polypropylene-based resin, and a styrene-based resin including an AS resin). The shape of the light guide plate is not limited to a flat plate, and may be a curved shape. As described above, the dimming device may be curved.

[0147] In the display device or the like of the present disclosure, a light shielding member for shielding incidence of external light on the optical device may be disposed in a region of the optical device on which light emitted from the image forming device is incident. By disposing the light shielding member for shielding incidence of external light on the optical device in a region of the optical device on which light emitted from the image forming device is incident, even if the amount of incident external light changes due to operation of the dimming device, in the first place, external light is not incident on the region of the optical device on which light emitted from the image forming device is incident. Therefore, deterioration in image display quality of the display device due to generation of undesirable stray light or the like does not occur. The region of the optical device on which light emitted from the image forming device is incident is preferably included in a projected image of the light shielding member on the optical device.

[0148] Alternatively, in the display device or the like of the present disclosure, a light shielding member for shielding incidence of external light on the first deflecting means may be disposed in a region of the first deflecting means on which light emitted from the image forming device is incident. By disposing the light shielding member for shielding incidence of external light on the light guide plate in a region of the light guide plate on which light emitted from the image forming device is incident, external light is not incident on the region of the light guide plate on which light emitted from the image forming device is incident. Therefore, deterioration in image display quality of the display device due to generation of undesirable stray light or the like does not occur. The region of the light guide plate on which light emitted from the image forming device is incident is preferably included in an orthogonally projected image of the light shielding member on the light guide plate.

[0149] The light shielding member may be disposed away from the optical device (light guide plate) on the opposite side to a side where the image forming device is disposed in the optical device (light guide plate). In the display device having such a configuration, the light shielding member only needs to be manufactured, for example, from an opaque plastic material. Such a light shielding member may integrally extend from a casing of the image forming device, may be attached to the casing of the image forming device, may integrally extend from a frame, or may be attached to the frame. Alternatively, the light shielding member may be disposed in a portion of the optical device (light guide plate) on the opposite side to a side where the image forming device is disposed, or may be disposed in the dimming device. For example, a light shielding member containing an opaque material may be formed on a surface of the optical device (light guide plate) on the basis of a PVD method or a CVD method, a printing method, or the like. A film, a sheet, or a foil including an opaque material (plastic material, metal material, alloy material, or the like) may be stuck to the surface of the optical device (light guide plate). A projected image of an end portion of the dimming device on the optical device (light guide plate) is preferably included in a projected image of a light shielding member on the optical device (light guide plate).

[0150] In the display device or the like of the present disclosure, as described above, the frame may include a front portion disposed in front of an observer and two temple portions rotatably attached to both ends of the front portion via hinges. A modern portion is attached to a distal end portion of each of the temple portions. The image display device is attached to the frame. Specifically, for example, it is only required to attach the image forming device to the temple portions. Furthermore, the front portion and the two temple portions may be integrally formed. In other words, when the entire display device or the like of the present disclosure is viewed, the frame has substantially the same structure as that of ordinary eyeglasses. A material constituting the frame including a pad portion may be the same material as a material constituting ordinary eyeglasses, such as metal, alloy, plastic, or a combination thereof. Furthermore, a nose pad may be attached to the front portion. That is, when the entire display device or the like of the present disclosure is viewed, an assembly of the frame (including a rim portion) and the nose pad has substantially the same structure as that of ordinary eyeglasses. The nose pad may also have a well-known configuration and structure.

[0151] Furthermore, in the display device or the like of the present disclosure, wiring (signal line, power supply line, or the like) from one or two image forming devices desirably extends from a distal end portion of a modern portion to the outside via a temple portion and the inside of the modern portion to be connected to a control device (control circuit or control means) from a viewpoint of design or ease of mounting. Furthermore, each image forming device may include a headphone portion, and headphone portion wiring from each image forming device may extend from a distal end portion of the modern portion to the headphone portion via the temple portion and the inside of the modern portion. Examples of the headphone portion include an inner ear type headphone portion and a canal type headphone portion. More specifically, the headphone portion wiring preferably extends from a distal end portion of the modern portion to the headphone portion so as to go around a back side of the auricle (auditory capsule). Furthermore, a camera (imaging device) may be attached to the central portion of the front portion. Specifically, the camera includes, for example, a solid-state imaging element including a CCD or CMOS sensor and a lens. Wiring from the camera only needs to be connected to one of the image display devices (or the image forming devices), for example, via the front portion. Furthermore, the wiring only needs to be included in the wiring extending from the image display device (or the image forming device).

[0152] The display device of the present disclosure may receive a signal for displaying an image in the image display device (a signal for forming a virtual image in the optical device (for example, light guide plate)) from the outside. In such a form, information and data regarding an image to be displayed on the image display device is recorded, stored, and saved, for example, in a so-called cloud computer or a server. By inclusion of communication means such as a mobile phone or a smartphone in the display device or by combination of the display device and the communication means, various kinds of information and data can be transmitted and exchanged between the cloud computer or the server and the display device, and a signal based on various kinds of information and data, that is, a signal for displaying an image in the image display device (a signal for forming a virtual image in the optical device) can be received. Alternatively, a signal for displaying an image in the image display device (a signal for forming a virtual image in the optical device) may be stored in the display device. An image displayed on the image display device includes various kinds of information and various kinds of data. Alternatively, the display device may include a camera (imaging device). An image imaged by the camera may be sent to a cloud computer or a server via communication means. The cloud computer or the server may retrieve various kinds of information and data corresponding to the image imaged by the camera. The various kinds of information and data retrieved may be sent to the display device via the communication means. An image of the various kinds of information and data retrieved may be displayed on the image display device.

[0153] When the image imaged by the camera (imaging device) is sent to the cloud computer or the server via the communication means, the image imaged by the camera may be displayed on the image display device and may be confirmed by the optical device (for example, light guide plate). Specifically, an outer edge of a space region imaged by the camera may be displayed in a frame shape in the dimming device. Alternatively, the light shielding ratio of a region of the dimming device corresponding to the space region imaged by the camera may be higher than the light shielding ratio of a region of the dimming device corresponding to the outside of the space region imaged by the camera. In such a form, an observer sees the space region imaged by the camera darker than the outside of the space region imaged by the camera. Alternatively, the light shielding ratio of a region of the dimming device corresponding to the space region imaged by the camera may be lower than the light shielding ratio of a region of the dimming device corresponding to the outside of the space region imaged by the camera. In such a form, an observer sees the space region imaged by the camera brighter than the outside of the space region imaged by the camera. In addition, this makes it possible for an observer to easily and reliably recognize a position in the outside to be imaged by the camera.

[0154] A position in a region of the dimming device corresponding to the space region imaged by the camera (imaging device) can be calibrated. Specifically, for example, by inclusion of a mobile phone or a smartphone in the display device or by combination of the display device with the mobile phone, the smartphone, or a personal computer, the mobile phone, the smartphone, or the personal computer can display a space region imaged by the camera. In addition, in a case where there is a difference between a space region displayed on the mobile phone, the smartphone, or the personal computer and a region of the dimming device corresponding to a space region imaged by the camera, by moving/rotating or enlarging/reducing a region of the dimming device corresponding to the space region imaged by the camera using a control circuit (which can be substituted by a mobile phone, a smartphone, or a personal computer) for controlling a light shielding ratio (light transmittance) of the dimming device, it is only required to eliminate the difference between the space region displayed on the mobile phone, the smartphone, or the personal computer and the region of the dimming device corresponding to the space region imaged by the camera.

[0155] The display device of the present disclosure including the above-described various modified examples can be used, for example, for receiving/displaying an electronic mail; display of various kinds of information or the like in various sites on the Internet; display of various explanations, for example, for driving, operating, maintaining, or disassembling an observation object such as various devices, a symbol, a sign, a mark, an emblem, a design, or the like; display of various explanations concerning an observation object such as a person or an article, a symbol, a sign, a mark, an emblem, a design, or the like; display of a moving image and a still image; display of subtitles of a movie and the like; display of descriptive text concerning video synchronized with video and closed caption; and display of various explanations concerning an observation object in play, Kabuki, Noh, Kyogen, opera, concert, ballet, various dramas, an amusement park, a museum, a sightseeing spot, a holiday destination, tourist information, and the like, and descriptive text or the like for explaining contents thereof, progress status thereof, backgrounds thereof, and the like, and can be used for display of closed caption. In play, Kabuki, Noh, Kyogen, opera, concert, ballet, various dramas, an amusement park, a museum, a sightseeing spot, a holiday destination, tourist information, and the like, it is only required to display characters as an image relating to an observation object on the display device at an appropriate timing. Specifically, for example, in accordance with progress status of a movie or the like, or in accordance with progress status of a play or the like, an image control signal is sent to the display device, and an image is displayed on the display device on the basis of a predetermined schedule or time allocation by operation of an operator or under control of a computer or the like. Furthermore, various kinds of explanations concerning an observation object such as various devices, a person, or an article are displayed. If the camera photographs (images) an observation object such as various devices, a person, or an article, and the display device analyzes the photographed (imaged) contents, the display device can display previously-created various explanations concerning an observation object such as various devices, a person, or an article.

[0156] An image signal to the image forming device may include not only an image signal (for example, character data) but also, for example, brightness data (brightness information) concerning an image to be displayed, chromaticity data (chromaticity information), or brightness data and chromaticity data. The brightness data may correspond to brightness of a predetermined region including an observation object viewed through the optical device (for example, light guide plate). The chromaticity data may correspond to chromaticity of a predetermined region including an observation object viewed through the optical device. In this way, by inclusion of brightness data concerning an image, brightness (lightness) of an image displayed can be controlled. By inclusion of chromaticity data concerning an image, chromaticity (color) of an image displayed can be controlled. By inclusion of brightness data and chromaticity data concerning an image, brightness (lightness) and chromaticity (color) of an image displayed can be controlled. In a case where brightness data corresponds to brightness of a predetermined region including an observation object viewed through the optical device, it is only required to set a value of brightness data such that the higher a value of brightness of a predetermined region including an observation object viewed through the optical device is, the higher a value of brightness of an image is (that is, the lighter an image is displayed). Furthermore, in a case where chromaticity data corresponds to chromaticity of a predetermined region including an observation object viewed through the optical device, it is only required to set a value of chromaticity data such that chromaticity of a predetermined region including an observation object viewed through the optical device has a roughly complementary color relationship with chromaticity of an image to be displayed. A complementary color refers to a combination of colors diametrically opposed to each other in a color circle. The complementary color also means a complementary color, for example, green for red, violet for yellow, and orange for blue. The complementary color also means a color to cause a decrease in color saturation by mixing a certain color with another color at an appropriate ratio, for example, white in a case of light and black in a case of an object. However, a complementary property in visual effects in parallel disposition is different from a complementary property in mixing. The complementary color is also referred to as a surplus color, a control color, or an opposite color. However, the opposite color directly indicates a color opposite to a complementary color, whereas a range indicated by the complementary color is slightly wider. A color combination of complementary colors has a synergistic effect for bringing mutual colors into prominence, and this is referred to as complementary color harmony.

[0157] The display device or the like of the present disclosure can constitute, for example, a head mounted display (HMD). In addition, this makes it possible to reduce the weight and size of the display device, to largely reduce discomfort when the display device is mounted, and further to reduce manufacturing cost. Alternatively, the display device or the like of the present disclosure can be applied to a head-up display (HUD) disposed in a cockpit of a vehicle or an aircraft, or the like. Specifically, in a HUD in which a virtual image forming region where a virtual image is formed on the basis of light emitted from an image forming device is disposed on a windshield of a cockpit of a vehicle or an aircraft, or the like, or in a HUD in which a combiner having a virtual image forming region where a virtual image is formed on the basis of light emitted from an image forming device is disposed on a windshield of a cockpit of a vehicle or an aircraft, or the like, the virtual image forming region and the combiner only need to overlap with at least a part of a dimming device. The display device or the like of the present disclosure can also be used as a stereoscopic displaying device. In this case, if necessary, it is only required to detachably attach a polarizing plate or a polarizing film to an optical device (for example, light guide plate), or to stick the polarizing plate or the polarizing film to the optical device.

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