CN1466408A - Method for detecting and adjusting brightness of liquid crystal display - Google Patents

Abstract

The present invention provides a method for adjusting and detecting the brightness of a backlight source of a liquid crystal display. The adjustment method includes setting a predetermined value with brightness information. Then, a light sensor is used to detect the brightness of the backlight source, and a detection value is obtained, and the detection value is an analog signal. Then, the analog signal is converted into a digital signal through an analog/digital converter, and then the microprocessor compares the digital signal with the predetermined value. Then, if the digital signal is not equal to the predetermined value, the microprocessor determines an adjustment value, and adjusts the brightness of the backlight source according to the adjustment value.

Description

Detection and Adjustment Method of LCD Brightness

Technical field

The invention relates to a liquid crystal display, in particular to a liquid crystal display capable of adjusting and detecting screen brightness.

Background technique

A liquid crystal display with a backlight refers to a liquid crystal panel that is illuminated by a backlight on the back of the display. After the light is output, it passes through the LCD panel to display the image. This LCD panel has enough high contrast to allow users to see images clearly even in dark places.

Generally speaking, the light source used in the backlight must have the characteristics of high brightness and long life. At present, there are cold cathode fluorescent lamps (cold cathode fluorescent tube), LED, electroluminescence (EL), etc., among which cold cathode fluorescent tubes are used. Lighting (CCFL) is the mainstream. As far as the position of the light source is concerned, it can be divided into two types: direct-lit and side-lit. Since the direct-lit module is thicker, it does not conform to the trend of lightness, thinness and shortness. Therefore, at present, the side-lit type is mainly used.

Liquid crystal displays have a wide range of applications. Most of the most common applications in the early days were applied to digital products, such as calculators or watches. In recent years, the size of liquid crystal displays has become larger and larger, so the scope of application is not limited to small digital products, but more diverse and complex. For example, the most common applications today are desktop computers, laptop computers, or the like.

However, the brightness of the lamp tube on the backlight will gradually decrease as the time of use increases. When the brightness is not enough, initial users may not be aware of it, but it will still damage eyesight. Therefore, it is necessary to provide a system, so that the user can be notified in time when the brightness of the backlight source is reduced, and an appropriate brightness adjustment can be made.

Contents of invention

An object of the present invention is to provide a method for automatically adjusting the brightness of a backlight source in a liquid crystal display.

Another object of the present invention is to provide a method for detecting the brightness of a backlight source in a liquid crystal display.

The liquid crystal display includes a backlight (backlight), a light sensor (luminance sensor), an analog/digital converter (A/D converter), a microprocessor (microprocessor), and a memory. The adjusting method includes setting a predetermined value with brightness information, and storing the set value in the memory. Then turn on the backlight, and use the light sensor to detect the brightness of the backlight, and obtain a signal. This analog signal is then converted into a digital signal by an analog/digital converter. After the analog signal is converted into a digital signal, the microprocessor compares and analyzes the digital signal with a predetermined value, and obtains a result. Next, it is judged whether the result is that the digital signal is equal to a predetermined value. If the digital signal is not equal to the predetermined value, the microprocessor will determine an adjustment value, and adjust the brightness of the backlight according to the adjustment value.

The detection method includes the microprocessor sending a signal to turn on the brightness of the backlight source to the maximum brightness. Then the light sensor detects the brightness signal of the maximum brightness. This signal is then converted from analog to digital via an analog/digital converter. After conversion, the microprocessor analyzes and compares the digital signal, and obtains a result. The next step is for the microprocessor to determine what the result is. If the result is that the signal representing the maximum brightness is greater than or equal to the predetermined value stored in the memory, the display outputs a signal to inform the user that there is no need to replace the light source of the backlight. Conversely, if the signal is smaller than the predetermined value, the display also outputs a signal to inform the user that the backlight needs to be replaced.

Description of drawings

Fig. 1 is the block diagram of device of the present invention;

Fig. 2 is the method flowchart of embodiment 1 of the present invention; And

Fig. 3 is a flow chart of the method in Embodiment 2 of the present invention.

The reference signs in the accompanying drawings are explained as follows:

10 LCD Display 12 Backlight

14 Light Sensor 16 Analog/Digital Converter

18 Microprocessor 20 Memory

Detailed ways

The invention provides a method for adjusting the brightness of a backlight source of a liquid crystal display. Figure 1 is a block diagram of the present invention. As shown in FIG. 1 , the liquid crystal display 10 includes a backlight (backlight) 12, a light sensor (luminance sensor) 14, an analog/digital converter (A/D converter) 16, a microprocessor (microprocessor) 18, and a memory 20. The light sensor 14 is used to detect the brightness of the backlight 12 . The analog/digital converter 16 converts the analog signal into a digital signal. The microprocessor 14 is used for comparing the detection result with the preset value and transmitting instructions for controlling the brightness of the backlight 12 . The memory 20 is used for storing a predetermined value. The predetermined value includes brightness information.

Please refer to FIG. 2 . FIG. 2 is a flow chart of the brightness adjustment method of the first embodiment. Embodiment 1 of the present invention is applied to the brightness setting of liquid crystal displays when they leave the factory, and computerized and automatic adjustments can be used to avoid time-consuming and laborious manual adjustments. First, in step 501 , a predetermined value including brightness information needs to be set, and the set value is stored in the memory 20 . Next, in step 503, the backlight source 12 is turned on, and the light sensor 14 is used to detect the brightness of the backlight source 12 to obtain a signal. Since the signal is an analog signal X, in step 505, the analog signal X is converted into a digital signal Y by the analog/digital converter 16 for convenience of analysis.

After the analog signal X is converted into a digital signal Y, in step 507, the microprocessor 18 compares and analyzes the digital signal Y with a predetermined value, and obtains a result. Next, in step 509, the microprocessor 18 judges whether the digital signal Y is equal to a predetermined value. If the digital signal Y is not equal to the predetermined value, then in step 511, the microprocessor will determine an adjustment value. In step 513, the brightness of the backlight source 12 is adjusted according to the adjustment value. After adjustment, steps 503 , 505 , 507 , and 509 are repeated.

In step 509, if the digital signal Y is equal to the predetermined value, then in step 515, the adjustment operation is ended and the result is output. The way of outputting the result can be to display the comparison result directly on the screen with graphics or text, or to inform the user with sound. Or a combination of both to display the results.

Embodiment 2 of the present invention uses the same system to perform different detection functions. This embodiment is suitable for users who want to know the lifespan of the backlight source 12 of the liquid crystal display after the user has used the liquid crystal display for a period of time, the lifespan of the backlight source 12 can be measured by the method of the present invention, and a signal is sent to inform the user Whether the backlight source 12 needs to be replaced.

Please refer to FIG. 3 . FIG. 3 is a block flow diagram of Embodiment 2 of the present invention. Firstly, in step 601 , when the user detects the life of the backlight 12 , the microprocessor 18 sends a signal to turn on the brightness of the backlight 12 to the maximum brightness. Next, in step 603, the light sensor 14 detects the maximum brightness, and obtains a brightness signal X. Then in step 605 , the signal X is converted from an analog signal to a digital signal Y via the analog/digital converter 16 . After conversion, in step 607, the microprocessor 18 analyzes and compares the digital signal Y, and obtains a result.

In step 609, if the result is that the digital signal Y representing the maximum brightness is greater than or equal to the predetermined value stored in the memory 20, then in step 611, the microprocessor 18 outputs the first result that it is not necessary to replace the backlight source 12, and ends detection action. On the contrary, in step 613, if the signal Y is smaller than the predetermined value, the display will output the second result that the backlight source 12 needs to be replaced, and end the detection operation.

The above-mentioned display informs the user in the same manner as described in the first embodiment, by displaying graphics or text on the screen, or notifying the user by sound.

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

Through the detailed description of the above preferred specific embodiments, it is hoped that the features and spirit of the present invention can be described more clearly, rather than the scope of the present invention is limited by the preferred specific embodiments disclosed above. On the contrary, the intention is to cover various modifications and equivalent arrangements within the scope of the appended claims of the present invention.

Claims (14)

1. A method for adjusting the brightness of a backlight source for a liquid crystal display, the method comprising the following steps: (1.1) setting a predetermined value of the backlight brightness; (1.2) Detect the brightness of the backlight source to obtain X; (1.3) compare X with the predetermined value, and obtain a result; (1.4) If X is not equal to the predetermined value, then adjust the brightness of the backlight source; (1.5) Repeat steps (1.2), (1.3) and (1.4) until Y is equal to the predetermined value; and (1.6) End the adjustment and output the result. 2. The method of claim 1, wherein step (1.4) comprises: (2.1) Determine an adjustment value; (2.2) Adjust the brightness of the backlight according to the adjustment value. 3. The method as claimed in claim 1, wherein the result is output as an image. 4. The method as claimed in claim 1, wherein the result is output in a voice. 5. A method for adjusting the brightness of a backlight source, the backlight source being used for a liquid crystal display, the liquid crystal display comprising a light sensor, a microprocessor, an analog/digital converter, the method comprising the following steps: (5.1) Setting a predetermined value of the brightness of the backlight source; (5.2) The brightness of the backlight source detected by the light sensor is X; (5.3) converting X to Y by the analog/digital converter; (5.4) compare Y with the predetermined value by the microprocessor, and obtain a result; (5.5) If the result Y is not equal to the predetermined value, then an adjustment value is determined by the microprocessor; (5.6) Adjusting the brightness of the backlight according to the adjustment value; (5.7) Repeat steps (5.2), (5.3), (5.4), (5.5) and (5.6) until Y is equal to the predetermined value; and (5.8) The microprocessor outputs the result. 6. The method as claimed in claim 5, wherein step (5.8) outputs the result as an image. 7. The method of claim 5, wherein step (5.8) outputs the result audibly. 8. A method for detecting the brightness of a backlight source for a liquid crystal display, the liquid crystal display having a memory storing a predetermined value, the method comprising the following steps: (8.1) Turn on the backlight to a maximum brightness; (8.2) Detect the maximum brightness and obtain X; (8.3) Convert that X to Y; (8.4) comparing the Y with the predetermined value, and obtaining a result; (8.5) output the result. 9. The method of claim 8, wherein step (8.5) comprises: (9.1) If Y is greater than or equal to the predetermined value, output a signal that the backlight source does not need to be replaced; (9.2) If Y is less than the predetermined value, output a signal indicating that the backlight needs to be replaced. 10. The method as claimed in claim 8, wherein the result is output by outputting the signal as an image. 11. The method as claimed in claim 8, wherein the result is output by outputting the signal in a voice. 12. A method of detecting the brightness of a backlight for a liquid crystal display having a light sensor, an analog/digital converter, a microprocessor and a memory storing a predetermined value , the method includes the following steps: (12.1) Turn on the backlight to a maximum brightness; (12.2) Detect the maximum brightness by the light sensor to obtain X; (12.3) converting the X to Y by the analog/digital converter; (12.4) comparing the Y with the predetermined value by the microprocessor; (12.5) If Y is greater than or equal to the predetermined value, output a signal that the backlight source does not need to be replaced; and (12.6) If Y is less than the predetermined value, output a signal that the backlight needs to be replaced. 13. The method as claimed in claim 12, wherein steps (12.5) and (12.6) output the signal as an image. 14. The method of claim 12, wherein steps (12.5) and (12.6) output the signal audibly.

Images