KR101716726B1 - Image display device and driving method for thereof - Google Patents

Abstract

A method of driving an image display apparatus according to an embodiment of the present invention includes the steps of acquiring illuminance information by measuring external illuminance, acquiring color information and luminance information of a display image by analyzing an input image signal, Determining a visibility of the display image by comparing the information and the brightness information with a previously stored reference value, changing the hue of the image signal to a color having high visibility based on the visibility determination result of the display image, Changing a signal, and supplying a data voltage corresponding to a video signal in which at least one of hue and brightness is changed to a liquid crystal panel, thereby displaying an image.

Description

TECHNICAL FIELD [0001] The present invention relates to a video display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display apparatus, and more particularly, to an image display apparatus and a driving method capable of improving image quality by improving visibility of an image.

The display device has been developed in accordance with the market demand for the large-sized and thinned, and the demand for a flat panel display device having advantages of thinning, light weight, and low power consumption is increasing.

Examples of the flat panel display device include a liquid crystal display (LCD) device, a plasma display panel, a field emission display device, a light emitting diode display device ), An organic light emitting diode display device (Organic Light Emitting Diode Display Device) and the like have been developed.

Of the flat panel display devices, liquid crystal display devices have secured a strong market and are expanding their applications because of the advantages of mass production technology, ease of driving means, low power consumption, thin thickness, high image quality and large screen realization.

The liquid crystal display device displays an image by moving a liquid crystal according to an input video signal and adjusting light transmittance for each pixel.

To this end, a liquid crystal display device includes a liquid crystal panel in which a plurality of pixels (liquid crystal cells) are arranged in a matrix form; A backlight unit for supplying light to the liquid crystal panel; And a driving circuit for driving the liquid crystal panel and the backlight.

Visibility of an image displayed through such a liquid crystal display device may vary depending on various factors. For example, the visibility of an image depends on an environment in which colors, brightness and images according to input image data are displayed, that is, an illuminance (indoor illuminance, outdoor illuminance).

In particular, in recent years, a display image has a function of receiving information from a user as well as a function of transmitting information to a user, that is, a GUI (Graphic User Interface) Is becoming an important factor.

Since the liquid crystal display device is applied not only to a PC monitor, but also to a portable mobile device, when the user drives the liquid crystal display device from the outside, the visibility of the image displayed on the liquid crystal panel may be greatly reduced due to illumination.

When the image displayed on the liquid crystal display device is displayed with a high luminance, it is less affected by the visibility depending on the illuminance of the indoor environment and the outdoor environment. However, since the display image is not always displayed at a high luminance, there is a problem that the user can not accurately confirm the contents of the display image in the case of the image displayed with low luminance.

In order to solve such a problem, a technique of increasing the luminance of a displayed image has been proposed, but there is another problem that power consumption is increased to improve visibility.

An object of the present invention is to provide an image display apparatus and a driving method capable of enhancing the visibility of a display image.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image display device and a driving method capable of enhancing the visibility of a GUI (Graphic User Interface).

Other features and advantages of the invention will be set forth in the description which follows, or may be obvious to those skilled in the art from the description and the claims.

A method of driving an image display apparatus according to an embodiment of the present invention includes the steps of acquiring illuminance information by measuring external illuminance, acquiring color information and luminance information of a display image by analyzing an input image signal, Determining a visibility of the display image by comparing the information and the brightness information with a previously stored reference value, changing the hue of the image signal to a color having high visibility based on the visibility determination result of the display image, Changing a signal, and supplying a data voltage corresponding to a video signal in which at least one of hue and brightness is changed to a liquid crystal panel, thereby displaying an image.

The method of driving an image display apparatus according to an exemplary embodiment of the present invention is a method of displaying an image by changing at least one of a hue and a luminance of a video signal when a display image is determined to have low visibility as a result of a comparison between hue information and a hue reference value Increase.

The method of driving an image display apparatus according to an embodiment of the present invention is a method of driving an image display apparatus in which at least one of a hue and a luminance of a video signal is changed when a display image is determined to be low in visibility, Increase.

An image display apparatus according to an exemplary embodiment of the present invention includes an illuminance measurement unit for measuring external illuminance and generating external illuminance information, an image analysis unit for analyzing the input image signal to generate color information and luminance information of the display image, The color information and the luminance information are compared with a reference value stored in the memory to determine the visibility of the display image and the color of the video signal is changed to a color having high visibility based on the visibility determination result of the display image, A liquid crystal panel for displaying an image using a data voltage according to a video signal in which at least one of hue and luminance is changed, a backlight for supplying light to the liquid crystal panel, and a backlight for controlling driving of the backlight And a driving unit.

The present invention can provide an image display apparatus and a driving method capable of enhancing the visibility of a display image according to color, brightness, and external illuminance of a display image.

The present invention can provide an image display device and a driving method capable of enhancing the visibility of a GUI (Graphic User Interface) according to display image color, luminance, and external illuminance.

In addition, other features and advantages of the present invention may be newly understood through embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an image display apparatus according to an embodiment of the present invention; FIG.
2 is a view showing the image control unit shown in Fig.
3 is a diagram illustrating a method of driving an image display apparatus according to an embodiment of the present invention.
4 is a diagram showing visibility according to CIE 1976 color coordinates;
5 is a view showing visibility of an image according to color;
6 is a view showing visibility according to external illuminance and luminance of an image.

Hereinafter, an image display apparatus and a driving method according to embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a view illustrating an image display apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating an image control unit shown in FIG. 1. Referring to FIG. The image display apparatus according to the embodiment of the present invention shown in FIG. 1 shows a liquid crystal display device among various flat panel display devices as an example.

1, an image display apparatus 100 according to an exemplary embodiment of the present invention includes a liquid crystal panel 110; A gate driver 120; A data driver 130; A backlight unit 140; A backlight driving unit 150; A timing controller 160; An illuminance measurement unit 170; And an image control unit 180.

The liquid crystal panel 110 displays an image on input image data and includes a plurality of gate lines G1 to Gn and a plurality of data lines D1 to Dm.

A plurality of pixels are formed for each region defined by the intersection of the plurality of gate lines and the plurality of data lines. The plurality of pixels includes a storage capacitor Cst and a thin film transistor (TFT).

The timing controller 160 aligns the image signal 'data' input from the image controller 180 and converts the image signal data 'into digital image data R, G, and B for each frame, And supplies it to the driver 130.

Here, the video signal 'data' input from the video controller 180 may be the same as the source video signal 'data' input from the outside, and may be the same as the color, brightness, external illuminance (indoor illuminance, outdoor illuminance) And may be a converted video signal to improve visibility.

The timing controller 160 generates a gate control signal GCS for controlling the gate driver 120 by using the input vertical synchronization signal Vsync, the horizontal synchronization signal Hsync and the clock signal CLK, 130 in response to the data control signal DCS. The generated gate control signal GCS is supplied to the gate driver 120 and the data control signal DCS is supplied to the data driver 130.

The data control signal DCS includes a source start pulse SSP, a source sampling clock SSC, a source output enable SOE, and a polarity control signal POL, Polarity) and the like.

The gate control signal GCS may include a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable (GOE).

The gate driver 120 generates a scan signal (gate drive signal) for driving the TFT formed in each of the plurality of pixels based on a gate control signal (GCS) from the timing controller 160 . The generated scan signals are sequentially supplied to a plurality of gate lines formed in the liquid crystal panel 110 during one frame period, and TFTs formed in the respective pixels are driven by the scan signals to switch pixels.

The data driver 130 converts the digital image data (R, G, B) supplied from the timing controller 160 into an analog image data signal, that is, a data voltage. Based on the data control signal (DCS: Data Control Signal) from the timing controller 160, the analog data signal converted in accordance with the time when the TFT of each pixel is turned on is supplied to a plurality of data Line.

Since the liquid crystal panel 110 does not generate self-luminescence, the liquid crystal panel 110 displays an image using light supplied from the backlight unit 140.

The backlight unit 140 is for emitting light to the liquid crystal panel 110 and includes a plurality of backlights for generating light and a backlight unit for guiding light generated in the backlight toward the liquid crystal panel and improving the efficiency of light (A light guide plate, a diffusion plate, and a plurality of optical sheets).

Here, the CCFL (Cold Cathode Fluorescent Lamp), EEFL (External Electrode Fluorescent Lamp), and LED (Light Emitting Diode) can be applied as the backlight.

The backlight unit 140 includes a direct type in which a backlight is disposed in a lower direction of the liquid crystal panel 110 according to the structure in which the backlight is disposed and an edge type in which a backlight is disposed in a lateral direction of the liquid crystal panel 110 Can be distinguished. The image display apparatus and the driving method thereof according to the embodiment of the present invention can be applied to both the direct-type method and the edge-type method.

The backlight driver 150 controls driving (on-off) of the backlight, and controls the on-off time, duty, and brightness of the backlight according to the image data.

At this time, when image data is converted to improve the visibility of the display image in the image controller 180, the driving of the backlight is controlled based on the backlight control signal (BLCS) supplied from the image controller 180 can do.

For example, the backlight driver 150 controls the on / off timing of the backlight based on the backlight control signal BLCS, and generates a driving signal for controlling the brightness of the backlight (when the backlight is an LED, the PWM signal: pulse width modulation signal), and the luminance of the backlight can be controlled using the generated driving signal PWM. That is, the backlight driver 150 can control the duty of the PWM signal, which is the driving signal of the backlight, to lower or increase the brightness of the backlight.

The illuminance measuring unit 170 is for measuring the external illuminance of a liquid crystal display or an apparatus to which the liquid crystal display is applied, and may be implemented as an illuminance sensor for measuring the illuminance of external light. The illuminance measuring unit 170 is disposed outside the apparatus to which the liquid crystal display apparatus or the liquid crystal display apparatus is applied to measure external illuminance to generate illuminance information, and provides the generated illuminance information to the image control unit 180.

The image controller 180 analyzes the inputted image signal data to obtain color and brightness information of the display image, and outputs color information and luminance information according to the image signal and illuminance information provided from the illuminance measurement unit 170 And compares it with the reference value stored in the memory.

Thereafter, when it is determined that the visibility of the image according to the image signal inputted by the external illuminance is low based on the comparison result, the image signal is converted so that the visibility of the display image is improved. Then, the converted video signal 'data' is supplied to the timing controller 160.

When it is determined that the visibility of the image according to the input image signal is low, the backlight control unit 160 generates a backlight control signal BLCS for enhancing the visibility of the display image and provides the generated backlight control signal BLCS to the backlight driver 150 can do.

2, the image control unit 180 includes an image analysis unit 172, a memory 184, and a conversion unit 186. The image analysis unit 172 includes a memory 184,

3 to 6, a description will be given of the illuminance measurement unit 170, the image control unit 180, and the driving method of the image display apparatus 100 according to the embodiment of the present invention.

Referring to FIG. 4, the color difference cognition of green is different from that of other colors (blue, green, and blue) as in CIE (Commission Internationale de l'celairage) 1976 which is a color coordinate in consideration of UCS (Uniform Color Space) .

Referring to FIG. 5, when a display image includes a green background, an image, and a character, visibility is lower than that of black, red, and blue.

Referring to FIG. 6, the visibility is changed according to the background level of the display image and the external illuminance. The higher the brightness of the image, the higher the visibility and the higher the external illuminance, the lower the visibility.

As shown in FIG. 4, the visibility of the display image is lowered when the illuminance of the surrounding environment where the user uses the liquid crystal display device is high. At this time, depending on the color and brightness of the display image, It can be understood that the influence is affected.

The image display apparatus and the driving method according to the embodiment of the present invention apply the above-mentioned ideas and control the inputted image signal so that the visibility of the display image is increased according to the relationship between the external illuminance and the color and luminance of the display image.

As an example, in the case where the external illuminance is high, the image signal is transformed into a GUI having excellent recognition performance in order to increase the visibility of the display image, so that the visibility can be increased without increasing power consumption.

Specifically, the illuminance measurement unit 170 measures the external illuminance and supplies the measured illuminance information to the image control unit 170 (S10).

The image analyzing unit 182 analyzes the input image signal data to acquire color and luminance information of an image to be displayed (S20). The color and brightness information of the image is provided to the converting unit 186.

In the above description, it is described that the image analysis step of S20 is performed after the illuminance measurement step of S10, but this shows one embodiment of the present invention. In another embodiment of the present invention, the order of the illuminance measurement step S10 and the image analysis step S20 may be reversed, and steps S10 and S20 may be simultaneously performed.

In the memory 184, a color reference value according to the color of the display image, a luminance reference value according to the luminance of the display image, and an illuminance reference value according to the external illuminance are stored as a lookup table (LUT).

The conversion unit 186 converts the luminance information supplied from the luminance measurement unit 170 and the color and luminance information of the image supplied from the image analysis unit 182 into a color reference value, It is determined whether the display image according to the input image signal data is inferior in at least one of the reference values (S30).

As a result of the determination in S30, the converting unit 186 converts the color and luminance of the display image according to the image analysis result and the illuminance information supplied from the illuminance measuring unit 170 into the color reference value supplied from the memory 184, , And if it is less than at least one of the illuminance reference values, the image signal is converted into color and brightness having high visibility (S40). The converted video signal 'data' is supplied to the timing controller 160.

Also, as a result of the determination in S30, the converting unit 186 converts the color and brightness of the display image according to the image analysis result and the illuminance information supplied from the illuminance measuring unit 170 into the color reference value, The backlight control signal BLCS is generated so as to increase the brightness of the backlight when the brightness is less than at least one of the reference value and the illumination reference value. The generated backlight control signal BLCS is provided to the backlight driver 150. [

For example, when the color of the display image according to the image analysis result is less than the color reference value from the memory 184, the conversion unit 186 determines that the visibility of the display image according to the input image signal (data) And converts the video signal. At this time, when the color of the display image is green, the image signal is converted so as to be displayed in a different color having higher visibility than green, i.e., blue, red, and black.

Here, the color of the display image includes the colors of the background, the image, and the character, and the image signal is converted in consideration of the perceived characteristics of the person according to the color.

As another example, if the brightness of the display image according to the image analysis result is less than the brightness reference value from the memory 184, the converting unit 186 determines that the visibility of the display image according to the input image signal (data) And converts the video signal. At this time, the image signal is converted so that the gray level of the display image is equal to or higher than the luminance reference value. In addition, the image signal can be converted so that the colors of the display image are displayed in different colors with higher visibility.

As another example, the converting unit 186 may convert the luminance information provided from the luminance measuring unit 170, that is, the luminance of the display image according to the input video signal data, if the luminance value of the external illuminance is less than the luminance reference value from the memory 184. [ It is judged that visibility is low.

It is determined that visibility is low when an image is displayed according to an input image signal in an external illuminance environment and at least one of a gray level and a hue of the display image is controlled to convert the image signal so that the visibility of the display image is enhanced.

When the external illuminance is high, it is possible to increase the visibility of the display image according to the external illuminance by converting the image signal with a GUI having a high human perception characteristic, in order to increase the visibility of the display image. In addition, the brightness of the backlight can be controlled so that the visibility of the display image is enhanced.

Next, the timing controller 160 converts the converted image data 'data' so as to increase visibility from the image controller 180 into digital image data R, G, and B for each frame, and supplies the digital image data to the data driver 130 do.

The data driver 130 converts the supplied digital image data (R, G, B) into an analog image data signal, that is, a data voltage, and supplies the analog image data signal to the liquid crystal panel 110 so that the image is converted into image data with high visibility (S50).

If the illuminance information supplied from the color, luminance and illuminance measurement unit 170 of the display image according to the image analysis result is greater than or equal to the color reference value, the luminance reference value, and the illumination reference value supplied from the memory 184 in step S30 It is determined that the visibility of the display image according to the input video signal is high. At this time, the image is displayed on the first input video signal without converting the video signal (S60).

In the above description, the image controller 180 has been described as an independent separate structure within the image display apparatus 100, but this is an embodiment of the present invention. In another embodiment of the present invention, the image controller 180 may be embedded in the timing controller 160.

In the above description, the technical idea for improving the visibility of the display image of the present invention is described as being applied to the liquid crystal display device, but this is an embodiment of the present invention. The technical idea for improving the visibility of the display image of the present invention can be applied not only to a liquid crystal display but also to a plasma display panel, a field emission display, and an organic light emitting diode display.

It will be understood by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: image display device 110: liquid crystal panel
120: gate driver 130: data driver
140: backlight unit 150: backlight driving unit
160: timing controller 170: illuminance measuring unit
180: Image control unit 184:
184: Memory 186:

Claims (10)

Measuring external illuminance to obtain illuminance information;
Acquiring color information and brightness information of a display image by analyzing an inputted image signal;
Determining visibility of the display image by comparing the illuminance information, the color information, and the luminance information with a reference value previously stored in a memory;
Changing a color of a video signal to a color having high visibility or changing a video signal so that a brightness of a display image is high based on a result of visibility determination of the display image; And
And supplying a data voltage corresponding to a video signal in which at least one of a color and a luminance is changed to a liquid crystal panel to display an image,
Wherein the modifying the video signal comprises:
When the color of the display image according to the image analysis result is less than the color reference value from the memory, when the color of the display image is green, the color of blue, red, converts the video signal so as to be displayed in black,
And converting the image signal so that the gray level of the display image is equal to or greater than the luminance reference value if the luminance of the display image according to the image analysis result is less than the luminance reference value from the memory, wherein the image signal is converted to blue, red, or black. 2. The method according to claim 1, wherein the pre-
The color reference value serving as a criterion of visibility determination according to the color of the display image,
The brightness reference value serving as a criterion for determining the visibility according to the brightness of the display image,
An illuminance reference value for judging the visibility of the display image according to the external illuminance,
Wherein at least one of the color information, the luminance information, and the illumination information is compared with the reference value to determine the visibility of the display image according to the input image signal. 3. The method of claim 2,
Wherein the visibility of the display image is improved by changing at least one of the hue and brightness of the image signal if the display image is determined as low in visibility as a result of comparing the hue information and the hue reference value. 3. The method of claim 2,
Wherein the visibility of the display image is improved by changing at least one of the hue and brightness of the image signal when the display image is determined as low visibility as a result of comparing the illuminance information and the illuminance reference value. 3. The method of claim 2,
Wherein the luminance of the backlight is controlled so that the luminance of light supplied to the liquid crystal panel is higher when the display image is determined to have low visibility. An illuminance measurement unit for measuring external illuminance to generate external illuminance information;
An image analyzer for analyzing the input image signal to generate color information and luminance information of a display image;
The color of the image signal is changed to a color having high visibility or displayed on the basis of the visibility determination result of the display image by comparing the illumination information, color information, and luminance information with a reference value stored in a memory, A conversion unit for changing a video signal so that a brightness of an image is increased;
A liquid crystal panel for displaying an image using a data voltage according to a video signal in which at least one of a color and a luminance is changed;
A backlight for supplying light to the liquid crystal panel; And
And a backlight driver for controlling driving of the backlight,
Wherein,
When the color of the display image according to the image analysis result is less than the color reference value from the memory, when the color of the display image is green, the color of blue, red, converts the video signal so as to be displayed in black,
And converting the image signal so that the gray level of the display image is equal to or greater than the luminance reference value if the luminance of the display image according to the image analysis result is less than the luminance reference value from the memory, wherein the image signal is converted to blue, red, or black. The method according to claim 6,
The reference value stored in the memory
The color reference value serving as a criterion of visibility determination according to the color of the display image,
The brightness reference value serving as a criterion for determining the visibility according to the brightness of the display image,
An illuminance reference value for judging the visibility of the display image according to the external illuminance,
Wherein the converting unit compares at least one of the color information, the luminance information, and the illuminance information with the reference value to determine the visibility of the display image according to the input image signal. 8. The apparatus of claim 7, wherein the converting unit
Wherein the controller changes at least one of a hue and brightness of a video signal when the display image is determined to be low in visibility as a result of comparing the hue information and the hue reference value. 8. The apparatus of claim 7, wherein the converting unit
Wherein the controller changes at least one of a hue and a luminance of a video signal when the display image is determined to be low in visibility as a result of comparison between the roughness information and the roughness reference value. 8. The apparatus of claim 7, wherein the converting unit
If the display image is determined to have low visibility, a backlight control signal for controlling the brightness of the backlight is generated and supplied to the backlight driver,
Wherein the backlight driving unit increases the brightness of the backlight according to the backlight control signal.

Images