CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Republic of Korea Patent Application No. 10-2019-0179404, filed on Dec. 31, 2019, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a display device, and more particularly, to a display device that reduces luminance and color coordinate distortions during driving frequency conversion.

2. Description of the Related Art

An image display device that display various information using a screen is a key technology in an information communication era, and is developing toward a thinner, lighter, portable, and high-performance device. Accordingly, a display device capable of being manufactured in a thin and light form is attracting attention. Such a display device is embodied as a flat self-lighting-emitting device, which is not only advantageous in terms of power consumption based on low-voltage driving, but also has a high response speed, a high light-emitting efficiency, an excellent viewing angle, and an excellent contrast ratio and thus is being studied as a next-generation display. Such a display device implements an image using a plurality of sub-pixels arranged in a matrix form. Each of the plurality of sub-pixels includes a light-emitting element and a plurality of transistors that independently drive the light-emitting element.

Specific examples of a flat display device include a liquid crystal display device (LCD), a quantum dot display device (QD), a field emission display device (FED), an organic light-emitting display device (OLED), and the like. Among them, the organic light-emitting display device which does not require a separate light source and is in the spotlight as a device for compactness and clear color display has a high response speed, a high contrast ratio, a high luminous efficiency, a high luminance, and a wide viewing angle, due to using of an organic light-emitting diode (OLED).

A driving frequency may be automatically switched from SFR (Standard Frame Rate) to HFR (High Frame Rate) based on a type of an image such as a still image or a moving picture.

When driving the display device at the standard frame rate, a period of each of a vertical synchronization signal Vsync and a horizontal synchronization signal Hsync may be changed due to the switching of the driving frequency. For example, a period of each of the vertical synchronization signal and the horizontal synchronization signal at the high frame rate operating at 90 Hz may be shorter than a period of each of the vertical synchronization signal and the horizontal synchronization signal at the standard frame rate operating at 60 Hz.

As such, as the period of each of the vertical synchronization signal and the horizontal synchronization signal is changed, a duration of one horizontal period1H may vary, such that an operation duration of a sub-pixel may vary. Therefore, even when the same gamma value is applied to the same RGB image data, luminance and color coordinates may be changed due to the switching of the driving frequency. In other words, in order to reduce defects due to luminance and color coordinates variation during the driving frequency conversion, separate optical compensations for luminance and color coordinate should be executed for the standard frame rate and the high frame rate respectively to compensate for the luminance and color coordinates variation. Thus, when performing separate optical compensations at the standard frame rate and the high frame rate respectively, a manufacturing process time of the display device is prolonged.

SUMMARY

A purpose of the present disclosure is to provide a display device configured to solve the above problem, in which a horizontal synchronization signal of the display device is generated based on a driving frequency in a high frame rate, and an intermediate frequency and an interpolated gamma voltage corresponding thereto are generated during driving frequency conversion, thereby suppress luminance and color coordinate distortions.

The purposes of the present disclosure are not limited to the above-mentioned purposes. Other purposes and advantages of the present disclosure, as not mentioned above, may be understood from the following descriptions, and more clearly understood from the embodiments of the present disclosure. Further, it will be readily appreciated that the objects and advantages of the present disclosure may be realized by features and combinations thereof as disclosed in the claims.

A display device according to an embodiment of the present disclosure includes a display panel having a plurality of sub-pixels to display an image; a data driver for supplying image data to the plurality of sub-pixels; a gate driver for supplying a gate signal to the plurality of sub-pixels; a controller configured to convert a driving frequency of each of the data driver and the gate driver in a high frame rate mode; and a gamma voltage generator for generating gamma voltages respectively based on each driving frequency, wherein the controller is configured to generate a horizontal synchronization signal based on the driving frequency in the high frame rate mode.

Further, a display device according to an embodiment of the present disclosure includes a frequency converter for generating an intermediate frequency between a first driving frequency and a second driving frequency when converting a driving frequency from the first driving frequency to the second driving frequency; and a gamma voltage generator for generating gamma voltages respectively based on each of the first and second driving frequencies and for storing therein gamma voltages respectively based on each of the first and second driving frequencies, wherein gamma voltages respectively based on each of the first driving frequency and the second driving frequency is stored as a pre-compensated value, wherein a gamma voltage corresponding to the intermediate frequency is a value interpolated between a first gamma voltage corresponding to the first driving frequency and a second gamma voltage corresponding to the second driving frequency.

According to the embodiments of the present disclosure, even when the driving frequency conversion occurs, image quality levels corresponding to various driving frequencies respectively may be kept uniform by applying the same operation duration to the various driving frequencies.

Further, optical compensation is performed for some of various driving frequencies, the manufacturing process time of the device may be shortened, to improve the process efficiency.

Further specific effects of the present disclosure as well as the effects as described above will be described in conduction with illustrations of specific details for carrying out the present disclosure.

