CN101191926A - Liquid crystal display and gamma curve adjusting device and method thereof - Google Patents

Abstract

The present invention discloses a liquid crystal display and a gamma curve adjustment device and method thereof. The gamma curve adjustment device and method provided by the present invention adjust the gamma curve most suitable for human eyes according to the brightness change of the liquid crystal display's surrounding environment, so that not only can the user feel that the color brightness resolution of the liquid crystal display is high, but also the displayed picture will become clearer.

Description

Liquid crystal display and its gamma curve adjustment device and method

technical field

The present invention relates to a gamma curve adjustment device and method for a liquid crystal display, and in particular to a gamma curve adjustment device that can adjust the gamma value of the gamma curve at any time according to the brightness change of the surrounding environment of the liquid crystal display and its methods.

Background technique

The rapid progress of the multimedia society is mostly due to the rapid progress of semiconductor devices or display devices. As far as displays are concerned, thin film transistor liquid crystal displays (Thin Film Transistor Liquid Crystal Display, referred to as TFT-LCD) with superior characteristics such as high image quality, good space utilization efficiency, low power consumption, and no radiation have gradually become the mainstream of the market.

But it is worth mentioning that because the human eye’s ability to distinguish the brightness of light is not linear, the Video Electronics Standards Association (VESA) has formulated gamma based on the characteristics of the human eye in response to this phenomenon. The curve with a gamma value of 2.2 allows designers engaged in TFT-LCD related fields to pursue such brightness levels, so that the gray-scale images presented by TFT-LCD become the most suitable display images for human eyes.

However, because the gamma value curve formulated by VESA is 2.2, it is formulated in a darkroom environment, so when the TFT-LCD is in a very dark environment, it will display the same gray Gray level images, the human eye can clearly distinguish clear and layered gray levels, but when the TFT-LCD is in a bright environment, it displays many similar gray level images, At this time, the human eye cannot clearly distinguish different gray scales, which will make users feel that the resolution of color brightness of TFT-LCD is not good, and the displayed picture will become blurred. derived.

Contents of the invention

In view of this, the purpose of the present invention is to provide a gamma curve adjustment device and method thereof, which adjusts the gamma curve required to define the gray scale of the video signal according to the brightness change of the surrounding environment of the liquid crystal display, so that the The gamma curve becomes the most suitable gamma curve for human eyes to watch.

Another object of the present invention is to provide a liquid crystal display, which uses the gamma curve adjustment device and method proposed in the present invention, so that the liquid crystal display can display a The display screen is most suitable for viewing by human eyes, so that users feel that the color brightness of the liquid crystal display has a high resolution, and the displayed screen will become clearer.

Based on the above and other objectives, the gamma curve adjustment device provided by the present invention includes an ambient light processing unit, a gamma curve adjuster, and a system central controller. Wherein, the ambient light processing unit can adjust the brightness change of the surrounding environment of the device according to the gamma curve to output the brightness signal. The gamma curve adjuster adjusts the output gamma curve according to the brightness signal output by the ambient light processing unit. The system central controller defines the gray scale of the received video signal according to the gamma curve adjusted by the gamma curve adjuster.

From another point of view, the liquid crystal display provided by the present invention includes a gamma curve adjusting device and a liquid crystal display panel. Wherein, the gamma curve adjusting device adjusts the gamma curve required to define the gray scale of the video signal according to the brightness change of the surrounding environment of the liquid crystal display. The liquid crystal display panel displays the image of the video signal according to the gray scale of the video signal.

From another point of view, the gamma curve adjustment method provided by the present invention is applicable to liquid crystal displays, which includes the following steps: firstly, detecting the brightness change of the surrounding environment of the liquid crystal display. Then, the gamma curve required to define the gray scale of the video signal is adjusted according to the brightness variation of the surrounding environment of the liquid crystal display.

The gamma curve adjustment device and method provided by the present invention can be applied to current liquid crystal displays, because the gamma curve adjustment device and method provided by the present invention are adjusted according to the brightness change of the surrounding environment of the liquid crystal display. A gamma curve that is most suitable for human eyes is produced, so that not only can users feel that the color brightness of the liquid crystal display has a high resolution, but also the displayed pictures will become clearer.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments of the present invention will be exemplified below and described in detail with accompanying drawings.

Description of drawings

FIG. 1 is a block diagram of a liquid crystal display according to a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram of the tone gamma curve corresponding to the built-in look-up table of the gamma curve adjuster in a preferred embodiment of the present invention.

FIG. 3 is a flowchart of a gamma curve adjustment method according to a preferred embodiment of the present invention.

Detailed ways

The technical effect that the present invention intends to achieve is to solve the existing shortcoming that when the liquid crystal display is in a bright environment, it displays many similar gray scale pictures, and the human eye cannot clearly distinguish different gray scales, and The following content will be a detailed description of the technical features and desired effects of this case, so as to provide reference for those skilled in the art related to the invention.

FIG. 1 is a block diagram of a liquid crystal display according to a preferred embodiment of the present invention. Referring to FIG. 1 , a liquid crystal display (such as a thin film dot transistor liquid crystal display, TFT-LCD) 100 includes a gamma curve adjustment device 101 , a video signal generator 103 , and a liquid crystal display panel 105 . Wherein, the gamma curve adjusting device 101 will adjust the gamma curve (gamma curve) required to define the gray level (gray level) of the video signal VS provided by the video signal generator 103 according to the change of the brightness LS_int of the surrounding environment of the liquid crystal display 100. ). The liquid crystal display panel 103 will display the image of the video signal for the user to watch according to the gray scale of the video signal VS.

In this embodiment, the code curve adjusting device 101 includes an ambient light processing unit 101a, a gamma curve adjuster 101b, and a system central controller 101c. Wherein, the ambient light processing unit 101 a is composed of a light sensor (light sensor) 107 and an optical amplification processor 109 . First, the light sensor 107 senses the change of the brightness LS_int of the surrounding environment of the liquid crystal display 100 , and outputs a light sensing signal LSS accordingly. Next, the optical amplifier processor 109 amplifies the light sensing signal LSS output by the light sensor 107 by a gain value (the gain value should depend on the actual situation), and performs noise filtering and distortion compensation on it Output a luminance signal IS to the gamma curve adjuster 101b.

Afterwards, when the gamma curve adjuster 101b receives the luminance signal IS, its built-in lookup table (lookup table, not shown) will correspondingly find out the first-order gamma curve according to the luminance signal IS for gamma The gamma curve adjuster 101b adjusts the output gamma curve accordingly. In this way, the system central controller 101c (for example, a video signal IC) defines the gray scale of the video signal VS provided to it by the video signal generator 103 according to the gamma curve adjusted by the gamma curve adjuster 101b, In this way, the grayscale of the defined video signal VS is displayed on the liquid crystal display panel 105 for the user to watch.

What is worth mentioning here is that the look-up table built in the gamma curve adjuster 101b must go through a tedious experiment process to define the range of lumens within which the brightness LS_int of the surrounding environment of the liquid crystal display 100 changes. , which finds out the corresponding tone gamma curve, thereby adjusting the gamma curve most suitable for human eyes, so that users feel that the resolution of the color brightness of the liquid crystal display 100 is high, and the displayed picture will also become clearer.

FIG. 2 is a schematic diagram of the tone gamma curve corresponding to the built-in look-up table of the gamma curve adjuster 101b in this embodiment. The horizontal axis represents the video signal gray level (gray level), and the vertical axis represents the brightness (cd/m2) . Among the four tone gamma curves shown in Figure 2, the gamma value of the tone gamma curve of the solid line (-) is 2.2, and that of the tone gamma curve of the dotted line (---) The gamma value is 1.3, and the gamma value of the dotted line (-.-.-) tone gamma curve is an experimental value (for example, 2.0, 1.8...) obtained from cumbersome experiments, where the experimental value should be regarded as It depends on the actual situation, so it is not limited here.

It is worth mentioning that FIG. 2 shows four tone gamma curves as an example, but it is not limited thereto. That is to say, the user can relatively increase or decrease the number of the above-mentioned tone gamma curves according to actual needs.

FIG. 3 is a flow chart of a method for adjusting a gamma curve according to a preferred embodiment of the present invention. This method is suitable for a liquid crystal display and includes the following steps: First, as described in step S301, a light sensor (light sensor) is provided to Detects changes in the brightness of the environment around the LCD monitor. Next, as described in step S303 , according to the brightness change of the surrounding environment of the liquid crystal display, a corresponding first-order gamma curve is found in the lookup table. Finally, as described in step S305 , the gamma curve required to define the gray scale of the video signal is adjusted according to the tone gamma curve.

A simpler statement based on the above steps is: the LCD will adjust the gamma value (gamma value) of the gamma curve required to define the gray scale of the video signal at any time according to the brightness changes of the current surrounding environment. The concept of adjusting the gamma curve required to define the gray scale of the video signal due to changes in the brightness of the environment is within the scope of protection of the present invention.

To sum up, the gamma curve adjustment device and method provided by the present invention are applicable to current liquid crystal displays, so according to the spirit described in the above embodiments, the following advantages will be described:

The gamma value of the gamma curve output by the gamma curve adjuster is adjusted at any time because the ambient light processing unit senses the brightness change of the surrounding environment of the liquid crystal display, so whether the liquid crystal display is in a bright environment or a dark room, it will Users feel that the resolution of the color brightness of the liquid crystal display is high, and the displayed picture will become clearer.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection should be defined by the claims.

Claims (13)

1. A gamma curve adjustment device, comprising: An ambient light processing unit, which adjusts a brightness change of the surrounding environment of the device according to the gamma curve to output a brightness signal; a gamma curve adjuster, electrically coupled to the ambient light processing unit, and adjusts a gamma curve output by the gamma curve adjuster according to the brightness signal; and A system central controller is electrically coupled to the gamma curve adjuster, and defines a gray scale of a video signal received by the system central controller according to the gamma curve. 2. The gamma curve adjustment device according to claim 1, wherein the ambient light processing unit comprises: a light sensor for sensing the brightness change and outputting a light sensing signal accordingly; and An optical amplification processor, electrically coupled to the optical sensor, is used to amplify the optical sensing signal by a gain value, perform noise filtering and distortion compensation on it, and output the luminance signal. 3. The gamma curve adjusting device according to claim 1, wherein the gamma curve adjuster has a built-in look-up table, and the look-up table finds a first-order gamma curve correspondingly according to the luminance signal, It is used for the gamma curve adjuster to adjust the outputted gamma curve accordingly. 4. The gamma curve adjusting device according to claim 1, wherein the system central controller includes a video signal IC. 5. A liquid crystal display, comprising: a gamma curve adjustment device, which adjusts a gamma curve required to define a gray scale of a video signal according to a brightness change of the surrounding environment of the liquid crystal display; and The liquid crystal display panel is electrically coupled to the gamma curve adjustment device, and displays a video signal frame according to the gray scale of the video signal. 6. The liquid crystal display as claimed in claim 5, wherein the gamma curve adjusting device comprises: An ambient light processing unit, outputting a brightness signal according to the brightness change; a gamma curve adjuster, electrically coupled to the ambient light processing unit, and adjusts the gamma curve output by the gamma curve adjuster according to the brightness signal; and A system central controller is electrically coupled to the gamma curve adjuster, and defines the gray scale of the video signal received by the system central controller according to the gamma curve. 7. The liquid crystal display as claimed in claim 6, further comprising a video signal generator electrically coupled to the system central controller for providing the video signal. 8. The liquid crystal display according to claim 6, wherein the ambient light processing unit comprises: a light sensor for sensing the brightness change and outputting a light sensing signal accordingly; and An optical amplification processor, electrically coupled to the optical sensor, is used to amplify the optical sensing signal by a gain value, perform noise filtering and distortion compensation on it, and output the luminance signal. 9. The liquid crystal display as claimed in claim 6, wherein a look-up table is built in the gamma curve adjuster, and the look-up table finds a first-order gamma curve correspondingly according to the brightness signal for the The gamma curve adjuster adjusts the outputted gamma curve accordingly. 10. The liquid crystal display as claimed in claim 6, wherein the system central controller comprises a video signal IC. 11. A gamma curve adjustment method, the method is applicable to a liquid crystal display, comprising the following steps: detecting a change in brightness of the surrounding environment of the liquid crystal display; and A gamma curve required to define a gray scale of a video signal is adjusted according to the brightness variation. 12. The method for adjusting the gamma curve according to claim 11, further comprising the following steps in the step of detecting the brightness change of the surrounding environment of the liquid crystal display: A light sensor is provided to sense the brightness change. 13. The method for improving the gamma curve according to claim 11, further comprising the following steps in the step of adjusting the gamma curve required to define the gray scale of the video signal according to the brightness change: Correspondingly finding a first-tone gamma curve in a look-up table according to the brightness variation; and The gamma curve required to define the gray scale of the video signal is adjusted according to the tone gamma curve.

Images