Samsung Patent | Organic Light Emitting Display Device and Driving Method Thereof

Patent: Organic Light Emitting Display Device and Driving Method Thereof

Publication Number: 20190012961

Publication Date: 2019-01-10

Applicants: Samsung

Abstract

An organic light emitting display device comprises a first pixel region including first pixels which are driven in response to data signals when the organic light emitting display device is driven in a first mode and a second mode; a first scan driver which supplies scan signals to first scan lines connected to the first pixels; and a first light emitting driver which supplies light emission control signals to first light emission control lines which are connected to the first pixels. During one frame period in the second mode, the first light emitting driver supplies K light emission control signals to each of the first light emission control lines when a still image is displayed in the first pixel region, and supplies J light emission control signals to each of the light emission control lines when a moving image is displayed in the first pixel region.

Background

Recently, various electronic devices are developed, one of which can be directly worn on a body. Each of the devices is usually called a wearable device.

Particularly, a head-mounted display device (hereinafter referred to as an “HMD”), which is an example of the wearable device, displays a realistic image to provide a high level of immersion, thereby, being used for variety of purposes including movie watching.

Summary

Exemplary embodiments of the present disclosure are to provide an organic light emitting display device which can increase display quality and a driving method thereof.

According to one embodiment, an organic light emitting display device, which is driven in a second mode when being mounted on a wearable device and is driven in a first mode in other cases, includes a first pixel region that includes first pixels which are driven in response to data signals when the organic light emitting display device is driven in the first mode and the second mode; a first scan driver that supplies scan signals to first scan lines which are connected to the first pixels; and a first light emitting driver that supplies light emission control signals to first light emission control lines which are connected to the first pixels. During one frame period in the second mode, the first light emitting driver supplies k (k is a natural number greater than or equal to 2) light emission control signals to each of the first light emission control lines when a still image is displayed in the first pixel region, and supplies j (j is a natural number smaller than k) light emission control signals to each of the light emission control lines when a moving image is displayed in the first pixel region.

In the embodiment, during one frame period, total light emission time of the first pixels when the still image is displayed may be determined to be substantially the same as total light emission time of the first pixels when the moving image is displayed.

In the embodiment, k may be set to 2.sup.x (x is 1, 2, 3, 4, … ) times of j.

In the embodiment, the organic light emitting display device may further include a data driver that supplies the data signals to data lines which are connected to the first pixels; a gamma driver that supplies gamma voltages to the data driver; an offset part that stores offset values for controlling voltage the gamma voltages; and a timing controller that controls the offset values.

In the embodiment, in the second mode, the timing controller controls the offset values such that brightness of a low gray level when the still image is displayed becomes less than that when moving image is displayed in the first pixel region.

In the embodiment, the low gray level may include at least one gray level of 50 or less gray levels.

In the embodiment, the organic light emitting display device may further include a second pixel region that includes second pixels which are driven in response to the data signal when the organic light emitting display device is driven in the first mode and are set to a non-light emission state when the organic light emitting display device is driven in the second mode.

In the embodiment, the organic light emitting display device may further include a third pixel region that includes third pixels which are driven in response to the data signal when the organic light emitting display device is driven in the first mode and are set to the non-light emission state when the organic light emitting display device is driven in the second mode.

According to another embodiment, an organic light emitting display device, which is driven in a second mode when being mounted on a wearable device and is driven in a first mode in other cases, includes a first pixel region that includes first pixels which are driven in response to data signals when the organic light emitting display device is driven in the first mode and the second mode; a first scan driver that supplies scan signals to first scan lines which are connected to the first pixels; and a first light emitting driver that supplies light emission control signals to first light emission control lines which are connected to the first pixels. During one frame period in the second mode, the first light emitting driver supplies the light emission control signals to each of the first light emission control lines during a first period when a still image is displayed in the first pixel region, and supplies the light emission control signals to each of the light emission control lines during a second period different from the first period when a moving image is displayed in the first pixel region.

In the embodiment, the first period may be shorter than the second period.

In the embodiment, during one frame period in the second mode, the first pixels emit light for a longer time when the still image is displayed than when the moving image is displayed.

In the embodiment, during one frame period in the second mode, the first light emitting driver supplies one or more light emission control signals to each of the first light emission control lines when the still image is displayed in the first pixel region.

In the embodiment, the organic light emitting display device may further include a data converter that changes bits of first data which is supplied from the outside and generates second data, when the organic light emitting display device is driven in the second mode and simultaneously displays the still image in the first pixel region.

In the embodiment, the second data may have a lower gray level value than the first data.

In the embodiment, the organic light emitting display device may further include a data driver that generates a data signal by using the second data when the organic light emitting display device is driven in the second mode and simultaneously displays the still image in the first pixel region, and generates a data signal by using the first data in other cases.

In the embodiment, the organic light emitting display device may further include a second pixel region that includes second pixels which are driven in response to the data signal when the organic light emitting display device is driven in the first mode and are set to a non-light emission state when the organic light emitting display device is driven in the second mode.

In the embodiment, the organic light emitting display device may further include a third pixel region that includes third pixels which are driven in response to the data signal when the organic light emitting display device is driven in the first mode and are set to a non-light emission state when the organic light emitting display device is driven in the second mode.

According to still another embodiment, a driving method of an organic light emitting display device that is driven in a second mode when being mounted on a wearable device and is driven in a first mode in other cases, and that includes pixels which are turned off when a light emission control signal is supplied, includes supplying k (k is a natural number greater than or equal to 2) light emission control signals to each of light emission control lines, when the organic light emitting display device is driven in the second mode and a still image is simultaneously displayed in a pixel region; and supplying j (j is a natural number smaller than k) light emission control signals to each of the light emission control lines, when the organic light emitting display device is driven in the second mode and a moving image is simultaneously displayed in the pixel region.

In the embodiment, during one frame period, total light emission time of the pixels when the still image is displayed may be determined to be substantially the same as total light emitting time of the pixels when the moving image is displayed.

In the embodiment, k may be set to 2.sup.x (x is 1, 2, 3, 4, … ) times of j.

In an organic light emitting display device and a driving method thereof according to an embodiment of the present disclosure, when a display device is mounted on an HMD, the number of light emission control signals and/or widths of the light emission control signals supplied to each of light emission control lines in correspondence with a still image and a moving image are controlled.

For example, in the present disclosure, when a still image is displayed, more light emission control signals may be supplied than when a moving image is displayed such that a flicker phenomenon is minimized. In addition, in the present disclosure, when a still image is displayed, it is possible to supply a light emission control signal with a smaller width than when a moving image is displayed such that a flicker phenomenon is minimized. When the number of light emission control signals and/or widths of the light emission control signals supplied to each of light emission control lines are controlled in correspondence with the still image and the moving image, the flicker phenomenon in the still image may be minimized and a motion blur phenomenon in the moving image may be minimized.