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

Patent: Optical Device, Image Display Device, And Display Device

Publication Number: 20200150332

Publication Date: 20200514

Applicants: Sony

Abstract

An object of the present invention is to provide an optical device, an image display device, and a display device that can provide an image of high image quality. The optical device according to the present invention includes a first light guiding member (40) having a first surface to a sixth surface and including first deflecting means (41) and a second light guiding member (50) having a seventh surface to a twelfth surface and including second deflecting means 51; the first and third surfaces (40A, 40C) are parallel with each other; the second and fourth surfaces (40B, 40D) orthogonal to the first and third surfaces (40A, 40C) are parallel with each other; the seventh and ninth surfaces (50A, 50C) are parallel with an XY plane; light entering from the fifth surface (40E) is totally reflected within the first light guiding member (40), is deflected by the first deflecting means (41), is emitted from the third surface (40C), enters the eighth surface (50B), is totally reflected between the seventh surface (50A) and the ninth surface (50C), is deflected by the second deflecting means (51), and is emitted from the seventh surface (50A); the first deflecting means (41) includes a plurality of first semitransparent layers (42) provided so as to be separated from and in parallel with each other; and letting .alpha. and .beta., be angles formed between a normal to a first semitransparent layer (42) and an X-axis when the normal to the first semitransparent layer (42) is projected onto an XZ plane and the XY plane, the values of .alpha. and .beta., are values exceeding zero degrees.

TECHNICAL FIELD

[0001] The present disclosure relates to an optical device, an image display device including such an optical device, and a display device including such an image display device, and more particularly to a display device for use in a head-mounted display (HMD, Head Mounted Display).

BACKGROUND ART

[0002] In recent years, the development of a head-mounted display (HMD) that displays an image from an image forming device on an optical device disposed in front of the eyes of an observer has been earnestly pursued. Then, while head-mounted displays in various forms have been considered, the head-mounted displays are strongly desired to provide a wider angle of view of a display image in order to provide a more realistic image. A head-mounted display in which two deflecting means are arranged on a light guide plate constituting an optical device to address such a desire is well known from FIG. 16 of JP-T-2005-521099, for example. In this head-mounted display, as described in a paragraph number [0059] of the Japanese unexamined patent application publication, an input wave is coupled to the inside of a first LOE 20a by a first reflecting surface 16a and is propagated along a .xi.-axis. A selective reflecting surface 22a couples light to the outside of 20a, and this light is thereafter coupled to the inside of a second LOE 20b by a second reflecting surface 16b. Then, this light is propagated along an .eta.-axis, and thereafter coupled to the outside of 20b by a selective reflecting surface 22b.

CITATION LIST

Patent Literature

[PTL 1]

[0003] JP-T-2005-521099

SUMMARY

Technical Problem

[0004] However, with the technology disclosed in the above-described Japanese unexamined patent application publication, stray light is included in the light emitted from the first LOE 20a to the second LOE 20b, so that only an image of low image quality is obtained.

[0005] Hence, it is an object of the present disclosure to provide an optical device that can provide an image of high image quality, an image display device including such an optical device, and a display device including such an image display device.

Solution to Problem

[0006] An optical device according to the present disclosure for achieving the above object includes:

[0007] a first light guiding member having a first surface, a second surface, a third surface opposed to the first surface, a fourth surface opposed to the second surface, a fifth surface, and a sixth surface opposed to the fifth surface, and internally including first deflecting means;* and*

[0008] a second light guiding member having a seventh surface, an eighth surface, a ninth surface opposed to the seventh surface, a tenth surface opposed to the eighth surface, an eleventh surface, and a twelfth surface opposed to the eleventh surface, and internally including second deflecting means;

[0009] the first surface and the third surface being parallel with each other;

[0010] the second surface and the fourth surface being parallel with each other and orthogonal to the first surface and the third surface;

[0011] the seventh surface and the ninth surface being parallel with an XY plane in an XYZ orthogonal coordinate system;

[0012] light entering from the fifth surface being totally reflected within the first light guiding member, being deflected by the first deflecting means, being emitted from the third surface, entering the eighth surface disposed so as to be separated from the third surface, being totally reflected between the seventh surface and the ninth surface, being deflected by the second deflecting means, and being emitted from the seventh surface;

[0013] the first deflecting means including a plurality of first semitransparent layers provided so as to be separated from and in parallel with each other;

[0014] letting .alpha. be an angle formed between a normal to a first semitransparent layer and an X-axis when the normal to the first semitransparent layer is projected onto an XZ plane, a value of a being a value exceeding zero degrees;* and*

[0015] letting .beta. be an angle formed between the normal to the first semitransparent layer and the X-axis when the normal to the first semitransparent layer is projected onto the XY plane, a value of .beta. being a value exceeding zero degrees.

[0016] An image display device according to a first mode or a second mode of the present disclosure for achieving the above object includes an image forming device and an optical device, and the optical device includes the above-described optical device according to the present disclosure. Alternatively, the image display device includes an image forming device and the above-described optical device according to the present disclosure.

[0017] A display device according to a first mode or a second mode of the present disclosure for achieving the above object includes:

[0018] a frame mounted on a head of an observer;* and*

[0019] an image display device attached to the frame;

[0020] the image display device including an image forming device and an optical device;

[0021] the optical device including the above-described optical device according to the present disclosure.

[0022] Alternatively, the display device includes:

[0023] a frame mounted on a head of an observer;* and*

[0024] an image display device attached to the frame;

[0025] the image display device including an image forming device and the above-described optical device according to the present disclosure.

Advantageous Effect of Invention

[0026] In the optical device according to the present disclosure, the optical devices constituting the image display devices according to the first to second modes of the present disclosure, or the optical devices constituting the display devices according to the first to second modes of the present disclosure (these optical devices will hereinafter be referred to collectively as the “optical device according to the present disclosure and the like”), the value of .alpha. is a value exceeding zero degrees, and the value of .beta. is also a value exceeding zero degrees. It is therefore possible to suppress (reduce) inclusion of stray light in light (image) emitted from the first light guiding member. As a result, an image of high image quality can be provided. It is to be noted that effects described in the present specification are merely illustrative and are not limited, and there may be additional effects.

BRIEF DESCRIPTION OF DRAWINGS

[0027] FIG. 1 is a diagram schematically illustrating the arrangement of a first light guiding member and a second light guiding member in an optical device according to a first embodiment together with the behavior of light.

[0028] FIG. 2A is a diagram schematically illustrating the arrangement of the first light guiding member and the second light guiding member in the optical device according to the first embodiment illustrated in FIG. 1, FIG. 2B is a side view of the first light guiding member and the second light guiding member when the first light guiding member and the second light guiding member are viewed from the direction of an outlined arrow in FIG. 2A, and FIG. 2C is a side view of the first light guiding member and the second light guiding member when the first light guiding member and the second light guiding member are viewed from the direction of a black arrow in FIG. 2A.

[0029] FIG. 3 is a diagram schematically illustrating the arrangement of the first light guiding member and the second light guiding member when the optical device according to the first embodiment illustrated in FIG. 1 is applied to a binocular display device.

[0030] FIG. 4A and FIG. 4B are diagrams schematically illustrating states of arrangement of first light guiding members and second light guiding members in the display device according to the first embodiment and a display device according to a second embodiment.

[0031] FIG. 5A, FIG. 5B, and FIG. 5C are diagrams of assistance in explaining how the formation of an image resulting from stray light changes depending on an angle .alpha..

[0032] FIG. 6A and FIG. 6B are diagrams illustrating a result of evaluating, as a field-of-view diagonal angle value (unit: degree), an effective field-of-view range emitted from the first light guiding member when the angle .alpha. and an angle 3, are changed in the optical device according to the first embodiment.

[0033] FIG. 7A and FIG. 7B are diagrams illustrating a result of evaluating, as a field-of-view diagonal angle value (unit: degree), an effective field-of-view range emitted from the first light guiding member when the angle .alpha. and the angle 3, are changed in the optical device according to the first embodiment.

[0034] FIG. 8 (A), (B), (C), (D), (E), and (F) of FIG. 8 are diagrams illustrating a result of evaluating an effective field-of-view range emitted from the first light guiding member when the refractive index n of a material constituting the first light guiding member is changed in the optical device according to the first embodiment.

[0035] FIG. 9 is a schematic view of the display device according to the first embodiment as viewed from above.

[0036] FIG. 10 is a schematic view of the display device according to the first embodiment as viewed from a front.

[0037] FIG. 11A and FIG. 11D are schematic views of the display device according to the first embodiment and a modification thereof as viewed from a side, and FIG. 11B and FIG. 11C are schematic sectional views of the first light guiding member and the like.

[0038] FIG. 12A, FIG. 12B, and FIG. 12C are diagrams schematically illustrating an image forming device in a display device or an image display device according to the present disclosure.

[0039] FIG. 13 is a diagram schematically illustrating the arrangement of a first light guiding member and a second light guiding member in the optical device according to the second embodiment together with the behavior of light, an image forming device, and an observer.

[0040] FIG. 14 is a diagram schematically illustrating the arrangement of the first light guiding member and the second light guiding member in the optical device according to the second embodiment illustrated in FIG. 13.

[0041] FIG. 15A and FIG. 15B are diagrams of assistance in explaining relations between a first light guiding member constituting an optical device according to a third embodiment and the first light guiding member constituting the optical device according to the first embodiment and image nonuniformity.

[0042] FIG. 16 is a schematic sectional view of a light incidence part of a second light guiding member constituting the optical device according to the third embodiment.

[0043] FIG. 17A, FIG. 17B, and FIG. 17C are schematic perspective views of the first light guiding member constituting the optical device according to the third embodiment.

[0044] FIG. 18A and FIG. 18B are schematic diagrams of light incidence surfaces of the first light guiding members constituting the optical device according to the first embodiment and the optical device according to the third embodiment, and are schematic diagrams of image nonuniformity.

[0045] FIG. 19A and FIG. 19B are schematic diagrams of light incidence surfaces of first light guiding members constituting modifications of the optical device according to the third embodiment, and are schematic diagrams of image nonuniformity.

[0046] FIG. 20 is a schematic sectional view of a light incidence part of a first light guiding member constituting an optical device according to a fourth embodiment.

[0047] FIG. 21 is a schematic sectional view of a light incidence part of the first light guiding member constituting the optical device according to the first embodiment.

[0048] FIG. 22 (A) and (B) of FIG. 22 are diagrams illustrating light emission states in respective areas in a first light guiding member of an optical device according to a fifth embodiment and relation between an angle of reflection and optical reflectance.

DESCRIPTION OF EMBODIMENTS

[0049] The present disclosure will hereinafter be described on the basis of embodiments with reference to the drawings. However, the present disclosure is not limited to the embodiments, and various numerical values and materials in the embodiments are illustrative. Incidentally, the description will be made in the following order.

1. Optical Device according to Present Disclosure, Image Display Devices according to First to Second Modes of Present Disclosure, Display Devices according to First to Second Modes of Present Disclosure, and General Description 2. First Embodiment (Optical Device according to Present Disclosure, Image Display Devices according to First to Second Modes of Present Disclosure, and Display Devices according to First to Second Modes of Present Disclosure)

2. Second Embodiment (Modification of First Embodiment)

3. Third Embodiment (Modifications of First to Second Embodiments)

4. Fourth Embodiment (Modifications of First to Third Embodiments)

5. Fifth Embodiment (Modifications of First to Fourth Embodiments)

7.* Others*

[0050] In an optical device according to the present disclosure and the like,* a configuration can be adopted in which a first light guiding member is provided with*

[0051] a semitransparent mirror film provided in parallel with a first surface and a third surface,* or*

[0052] a semitransparent mirror film provided in parallel with a second surface and a fourth surface,* or*

[0053] a semitransparent mirror film provided in parallel with the first surface and the third surface and a semitransparent mirror film provided in parallel with the second surface and the fourth surface. Then, in this case, a configuration can be adopted in which the semitransparent mirror film provided in parallel with the first surface and the third surface within the first light guiding member is provided in a part of a region located at equal distances from the first surface and the third surface. Alternatively, a configuration can be adopted in which the semitransparent mirror film provided to the first light guiding member so as to be in parallel with the first surface and the third surface is provided in a part of a region on the first surface or a part of a region on the third surface. Alternatively, a configuration can be adopted in which the semitransparent mirror film provided in parallel with the second surface and the fourth surface within the first light guiding member is provided in a part of a region located at equal distances from the second surface and the fourth surface. Alternatively, a configuration can be adopted in which the semitransparent mirror film provided to the first light guiding member so as to be in parallel with the second surface and the fourth surface is provided in a part of a region on the second surface or a part of a region on the fourth surface. Then, thus providing the semitransparent mirror film to the first light guiding member can prevent the occurrence of nonuniformity (light and shade or shading) in an image emitted from the third surface of the first light guiding member. In a case where the semitransparent mirror film is provided in a part of a region on the first surface or a part of a region on the third surface or in a case where the semitransparent mirror film is provided in a part of a region on the second surface or in a part of a region on the fourth surface, a protective member is preferably provided on a surface of the semitransparent mirror film which surface is not in contact with the first light guiding member. It suffices to select the protective member from a material constituting a light guiding member to be described later as appropriate. Incidentally, in either of a case where the semitransparent mirror film is provided and a case where the semitransparent mirror film is not provided, the whole of at least one of the first surface, the second surface, the third surface, or the fourth surface of the first light guiding member is preferably covered with the protective member.