CN101290744A - Brightness Compensation Device and Method for Backlight Module - Google Patents

Abstract

A backlight module brightness compensation device and method are disclosed. The present invention uses a light sensing unit to sense the light source intensity of the backlight module, and calculates a difference parameter based on the light source intensity and a preset brightness, and then adjusts the gamma curve, video data or the light source intensity of the backlight module based on the difference parameter, so as to reduce the influence of the backlight module on the display quality due to the change of temperature or aging.

Description

Brightness Compensation Device and Method for Backlight Module

technical field

The invention relates to a brightness compensation device of a backlight module, in particular to a method for compensating the brightness of the backlight module by using light sensing technology.

Background technique

With the advancement of technology, Liquid Crystal Display (LCD for short) is becoming more and more popular. However, the liquid crystal display will age with time, especially the backlight module of the liquid crystal display. Some backlight modules mainly use light-emitting diodes (Light-Emitting Diodes, referred to as LEDs) to provide light sources. The intensity of light emitted by LEDs will change due to temperature and aging of components. In order for the liquid crystal display to display stable brightness and color, it is necessary to compensate the color and brightness of the backlight module as the backlight module ages.

FIG. 1 is a structural diagram of a known brightness compensation device for a backlight module, please refer to FIG. 1 . It includes a power converter 10 , a backlight driving unit 20 , a light emitting diode 30 , a light sensing unit 40 and a control unit 50 . The power converter 10 is used to provide the voltage required by the backlight driving unit 20 . The backlight driving unit 20 is used to provide voltage and current required by the LED 30 . The light emitting diode 30 generates a corresponding light source intensity according to changes in voltage and current. Then, the light sensing unit 40 is used to detect the intensity of the light emitted by the LED 30 and send a detection signal to the control unit 50 . The control unit 50 adjusts the backlight driving unit 20 according to the detection signal to achieve feedback adjustment of the light emitting diodes 30 . In this way, the brightness compensation of the backlight module is realized.

In addition, U.S. Patent Nos. 6,127,783, 6,344,641, 6,441,558, 6,448,550, 6,495,964, and 6,894,442 also propose methods similar to the above, the difference lies in the timing of driving, the position of the light sensing unit 40, the type of light sensor, and so on. It should be noted that in the above methods, the control unit 50 controls the brightness of the LED 30 according to the brightness sensed by the light sensing unit 40 . Not only does it require extra cost to increase the control unit 50, but the effect of adjusting the brightness of the light emitting diode 30 is also quite limited.

In view of this, relevant manufacturers of liquid crystal displays are eager to find a suitable solution to overcome the above-mentioned problems.

Contents of the invention

The invention provides a brightness compensation method of a backlight module, which compensates the brightness or color distortion of the LED of the backlight module due to aging or temperature by adjusting video data.

The invention provides a brightness compensation device for a backlight module, which uses a light sensing unit to sense the intensity of a light source of the backlight module, and then obtains the difference parameter between the intensity of the light source of the backlight module and a preset brightness, and then adjusts video data to improve display quality.

The invention proposes a brightness compensation method for a backlight module, which is suitable for a display device to present video data. The brightness compensation method includes the following steps. Sensing the light source intensity of the backlight module. The difference parameter is calculated according to the above-mentioned light source intensity and preset brightness. Adjust the video data according to the difference parameter.

In an embodiment of the present invention, the above brightness compensation method further includes adjusting a gamma curve according to a difference parameter, and the gamma curve is used to convert the brightness of the image video data.

The present invention proposes another brightness compensation device for a backlight module, which is suitable for a display device to present video data. The brightness compensation device includes a light sensing unit, a computing unit, and a calibration unit. The light sensing unit is used for sensing the light source intensity of the backlight module. The computing unit is coupled to the light sensing unit, and the computing unit calculates the difference parameter according to the intensity of the light source and the preset brightness. The correction unit is coupled to the computing unit. The correction unit adjusts the gamma curve and/or the video data according to the difference parameter. The gamma curve is used to convert the brightness of the image video data.

In an embodiment of the present invention, the above brightness compensation device, wherein the correction unit further includes a data mapping unit and a gamma mapping unit. The data mapping unit is coupled to the computing unit, and the data mapping unit adjusts the video data according to the difference parameter. The gamma mapping unit is coupled to the data mapping unit, and the gamma mapping unit adjusts the gamma curve according to the difference parameter.

In an embodiment of the present invention, the above-mentioned brightness compensation device, wherein the light sensing unit further includes a sensor and a signal conversion unit. The sensor is used to sense the above-mentioned light source intensity. The signal conversion unit is coupled between the computing unit and the sensor, and the signal conversion unit is used for converting the analog signal sensed by the sensor into a digital signal.

In the present invention, the light sensing unit is used to sense the light source intensity of the backlight module, and the difference parameter is calculated according to the above-mentioned light source intensity and preset brightness, and then the gamma curve and/or video data are adjusted according to the difference parameter, so as to reduce the temperature of the backlight module. Or brightness distortion caused by aging.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a structural diagram of a known brightness compensation device for a backlight module.

FIG. 2A is a structural diagram of a brightness compensation device for a backlight module according to the first embodiment of the present invention.

FIG. 2B is a flowchart of a brightness compensation method for a backlight module according to the first embodiment of the present invention.

FIG. 3 is a structural diagram of a brightness compensation device for a backlight module according to a second embodiment of the present invention.

FIG. 4 is a structural diagram of a brightness compensation device for a backlight module according to a third embodiment of the present invention.

FIG. 5 is a structural diagram of a brightness compensation device for a backlight module according to a fourth embodiment of the present invention.

FIG. 6 is a structural diagram of a brightness compensation device for a backlight module according to a fifth embodiment of the present invention.

FIG. 7 is a structural diagram of a brightness compensation device for a backlight module according to a sixth embodiment of the present invention.

FIG. 8 is a structural diagram of a brightness compensation device for a backlight module according to a seventh embodiment of the present invention.

Description of reference symbols

10: Power converter

20: Backlight drive unit

30: LED

31: Backlight module

40, 41, 42, 43: light sensing unit

50: Control unit

51: Operation unit

61, 62: Correction unit

70: sensor

71: Red light sensor

72: Green light sensor

73: Blue light sensor

80: Signal conversion unit

91: Data image unit

92: Gamma mapping unit

93: Timing controller

94: Display drive circuit

101: Substrate

S201～S203: are the steps of the flow chart in Figure 2B

Detailed ways

Fig. 2A is a structural diagram of a brightness compensation device for a backlight module according to the first embodiment of the present invention, and Fig. 2B is a flow chart of a brightness compensation method for a backlight module according to the first embodiment of the present invention, please refer to Fig. 2A with Figure 2B. The brightness compensation device includes a light sensing unit 41 , a computing unit 51 , and a correction unit 61 . The brightness compensation device is suitable for compensating the brightness of the backlight module 31 of the display device. The backlight source of the backlight module 31 emits corresponding light according to the voltage and current. In addition, in this embodiment, the backlight source of the backlight module 31 is particularly described by taking a red green blue (RGB) light emitting diode as an example to illustrate this embodiment. Those skilled in the art should understand that the "RGB LED" mentioned in this embodiment is only a specific embodiment. In another embodiment, the backlight of the backlight module 31 can still use cold cathode lamps, white light The light-emitting diodes are combined with filters to mix colors or use other forms of point light sources, line light sources, surface light sources, etc., so the present invention should not be limited to this specific embodiment.

Next, in step S201 , the light sensing unit 41 senses the intensity of the light source of the backlight module 31 . Next, step S202 is executed, and the calculation unit 51 calculates a difference parameter according to the sensed light source intensity and the preset brightness. The preset brightness mentioned here is the ideal expected brightness that the backlight module 31 should output. Finally, step S203 is executed again, and the correction unit 61 adjusts the video data and/or the gamma curve according to the difference parameter, wherein the gamma curve is used to convert the brightness of the image video data. In this way, not only the brightness distortion caused by the temperature or aging of the backlight module 31 can be compensated, but also the color distortion can be reduced. The correction unit 61 described in this embodiment adjusts the gamma curve according to the difference parameter. Those skilled in the art can also change the implementation according to their needs, for example, preset multiple gamma curves, and the correction unit 61 selects the gamma curve according to the difference parameter Horse curves.

FIG. 3 is a structural diagram of a brightness compensation device for a backlight module according to a second embodiment of the present invention, please refer to FIG. 3 . In this embodiment, the brightness compensation device includes a light sensing unit 42 , an arithmetic unit 51 and a correction unit 61 . The calculation unit 51 and the correction unit 61 are the same as those of the above-mentioned embodiments, and will not be repeated here. Noteworthy is the light sensing unit 42 . In this embodiment, the light sensing unit 42 includes a sensor 70 and a signal converting unit 80 . The sensor 70 is used for sensing the intensity of the light source of the backlight module 31 and outputting an electrical signal. In this embodiment, the electrical signal output by the sensor 70 is an analog signal, such as voltage or current.

The sensor 70 can have different types according to different embodiments, for example, the sensor 70 can be a photodiode (Photodiode), a light color sensor (Color Sensor) or an ambient light sensor (Ambient Light Sensor, referred to as ALS), etc. In other words, The sensor 70 generally refers to a photosensitive component having a function of detecting light.

The signal converting unit 80 is coupled between the computing unit 51 and the sensor 70 . A serial transmission interface (Serial Peripheral Interface, SPI) or an inter-integrated circuit (Inter-Integrated Circuit, IIC) interface can be used to transmit data between the signal converting unit 80 and the sensor 70 . The signal conversion unit 80 is used to convert the electrical signal provided by the sensor 70 , for example, in this embodiment, the signal conversion unit 80 converts the analog signal (voltage or current) provided by the sensor 70 into a digital signal. Not only that, the signal conversion unit 80 can also adjust the sampling frequency according to its requirement. Then the signal conversion unit 80 sends the digital signal to the computing unit 51 . The calculation unit 51 then calculates the difference parameter according to the digital signal and the preset brightness, and then the correction unit 61 adjusts the gamma curve and/or video data according to the difference parameter. In this way, not only the brightness of the backlight module 31 caused by temperature or aging can be compensated Distortion, but also reduce color distortion.

Although the electrical signal output by the sensor 70 in the above embodiments is an analog signal, in other embodiments, the sensor 70 can also directly output a digital signal. In this way, the sensor 70 can be directly provided to the calculation unit 51 for calculation. In addition, the signal conversion unit 80 is not only capable of converting analog signals into digital signals. For example, in a special embodiment, the signal conversion unit 80 can also convert voltage signals into current signals or convert current signals into voltage signals. Therefore, those skilled in the art can determine the type of signal converted by the signal conversion unit 80 according to their needs.

FIG. 4 is a structural diagram of a brightness compensation device for a backlight module according to a third embodiment of the present invention, please refer to FIG. 4 . In this embodiment, the brightness compensation device includes a light sensing unit 41 , an arithmetic unit 51 and a correction unit 62 . The photo-sensing unit 41 and the computing unit 51 are the same as those of the above-mentioned embodiments, and will not be repeated here. Of note is the correction unit 62 . In this embodiment, the calibration unit 62 includes a data mapping unit 91 and a gamma mapping unit 92 . The data mapping unit 91 is coupled to the computing unit 51 , and the data mapping unit 91 adjusts the video data according to the difference parameter calculated by the computing unit 51 . The data mapping unit 91 adjusts the video data in a digital to digital (Digital to Digital) manner, for example. More specifically, the calibration unit 62 can provide the digitized dynamic gamma curve to the data mapping unit 91 according to the difference parameter. The data mapping unit 91 adjusts the brightness of the video data with the gamma curve of memory mapping.

The gamma mapping unit 92 is coupled to the data mapping unit 91 . It should be noted that the gamma mapping unit 92 can also adjust the gamma curve according to the difference parameter. More specifically, the gamma mapping unit 92 can preset multiple gamma curves, and select different gamma curves according to the difference parameters, so as to adjust the brightness of the video data. It is worth mentioning that although the present embodiment uses the data mapping unit 91 and the gamma mapping unit 92 to adjust the brightness of the video data. However, in another embodiment, after the correction unit 62 receives the difference parameter calculated by the calculation unit 51 , only one of the data mapping unit 91 and the gamma mapping unit 92 can be used to adjust the video data. In this way, not only the brightness distortion caused by the temperature or aging of the backlight module 31 can be compensated, but also the color distortion can be reduced.

FIG. 5 is a structural diagram of a brightness compensation device for a backlight module according to a fourth embodiment of the present invention, please refer to FIG. 5 . The backlight module 31 , the light sensing unit 41 , the computing unit 51 , the calibration unit 62 , the data mapping unit 91 and the gamma mapping unit 92 in FIG. 5 are the same as those of the above-mentioned embodiments, and will not be repeated here. In this embodiment, after the correction unit 62 adjusts the video data according to the difference parameter, the correction unit 62 sends the adjusted video data to a timing controller (Timing Controller or Timing Generator) 93. The timing controller 93 is used to generate control signals and data signals required by each driving circuit of the display device. In other words, by disposing the calibration unit 62 in front of the timing controller 93 , the timing controller 93 can output the control signal and the adjusted video data to the display driving circuit 94 according to the adjusted video data. The display driving circuit 94 is used to drive the display device to present the adjusted video data, so that the brightness distortion of the backlight module 31 can be compensated. In this embodiment, the display driving circuit 94 generally refers to a source driver integrated circuit (Source Driver Integrated Circuit), a gate driver integrated circuit (Gate Driver Integrated Circuit) and related application circuits.

As mentioned above, those skilled in the art can also change the implementation according to the spirit of the present invention and the teachings of the foregoing embodiments according to their needs. For example, in another embodiment, the calibration unit 62 may also be disposed after the timing controller 93 . In other words, the correction unit 62 can be integrated in the display driving circuit 94 , for example, the data mapping unit 91 can be integrated in the source driving circuit. Another example is to integrate the gamma mapping unit 92 into the source driving circuit, etc. . . . The advantage of this method is that it does not need to add a new hardware structure, and the existing display device structure can be used to compensate the brightness and color distortion of the backlight module 31 caused by temperature or aging, which greatly reduces the hardware cost.

FIG. 6 is a structural diagram of a brightness compensation device for a backlight module according to a fifth embodiment of the present invention, please refer to FIG. 6 . In this embodiment, the brightness compensation device includes a light sensing unit 43 , an arithmetic unit 51 and a correction unit 61 . The light sensing unit 43 includes a red light sensor 71 , a green light sensor 72 , a blue light sensor 73 and a signal conversion unit 80 . The calculation unit 51 , the correction unit 61 and the signal conversion unit 80 can refer to the above-mentioned embodiments, and will not be repeated here. Noteworthy are the red light sensor 71 , the green light sensor 72 and the blue light sensor 73 . The red light sensor 71 is used to sense the intensity of the red light mainly in the backlight module 31 , and output the intensity of the red light source to the computing unit 51 through the signal conversion unit 80 . The green light sensor 72 is used to sense the intensity of the green light in the backlight module 31 , and output the intensity of the green light to the computing unit 51 through the signal conversion unit 80 . The blue light sensor 73 is used to sense the intensity of the light source mainly blue light in the backlight module 31 , and output the intensity of the blue light source to the computing unit 51 through the signal conversion unit 80 .

As described above, formula (3) can be derived using the following formulas (1), (2). The computing unit 51 then calculates the red difference parameter, the green difference parameter and the blue difference parameter according to the following formula (3). For the description of the formulas (1)-(3), please refer to the following Table 1.

V(R), V(G), V(B) The preset intensity of the red light source sensed by the red light sensor 71, the intensity of the green light source sensed by the green light sensor 72 and the intensity of the blue light source sensed by the blue light sensor 73. V _m (R), V _m (G), V _m (B) After factors such as aging or temperature change occur, the intensity of the red light source sensed by the red light sensor 71, the intensity of the green light source sensed by the green light sensor 72, and the intensity of the blue light source sensed by the blue light sensor 73. V _rr , V _gr , V _br Using a fixed driving current to continuously drive the red light emitting diode, the intensity of the red light source sensed by the red light sensor 71, the intensity of the green light source sensed by the green light sensor 72 and the intensity of the blue light source sensed by the blue light sensor 73. V _rg , V _gg , V _bg Use a fixed drive current to drive the green light-emitting diodes uninterruptedly. At this time, the intensity of the red light source sensed by the red light sensor 71, the intensity of the green light source sensed by the green light sensor 72 and the intensity sensed by the blue light sensor 73

The intensity of the blue light source for . V _rb , V _gb , V _bb Use a fixed driving current to continuously drive the blue light emitting diode. At this time, the intensity of the red light source sensed by the red light sensor 71, the intensity of the green light source sensed by the green light sensor 72, and the intensity of the blue light source sensed by the blue light sensor 73 . V _{r_dark} , V _{g_dark} , V _{b_dark} When the red light emitting diode, green light emitting diode and blue light emitting diode are all turned off, the intensity of the red light source sensed by the red light sensor 71, the intensity of the green light source sensed by the green light sensor 72 and the intensity sensed by the blue light sensor 73 The intensity of the blue light source. PWM(R) The preset lighting time of the red LED / the time period of the red LED lighting PWM(G) The preset lighting time of the green light-emitting diode / the time period of the green light-emitting diode lighting PWM(B) The preset lighting time of the blue LED / the time period of the blue LED lighting S ₁ red difference parameter S ₂ green difference parameter S ₃ blue difference parameter

Table 1: Explanation of formulas (1) to (3)

V(R)＝(V _rr -V _{r_dark} )*PWM(R)+(V _rg -V _{r_dark} )*PWM(G)+

(V _rb -V _{r_dark} )*PWM(B)+V _{r_dark}

V(G)＝(V _gr -V _{g_dark} )*PWM(R)+(V _gg -V _{g_dark} )*PWM(G)+

(V _gb -V _{g_dark} )*PWM(B)+V _{g_dark}

V(B)＝(V _br -V _{b_dark} )*PWM(R)+(V _bg -V _{b_dark} )*PWM(G)+

(V _bb -V _{b_dark} )*PWM(B)+V _{b_dark}

...Formula 1)

V _m (R)＝S ₁ (V _rr -V _{r_dark} )*PWM(R)+S ₂ (V _rg -V _{r_dark} )*PWM(G)+

S ₃ (V _rb -V _{r_dark} )*PWM(B)+V _{r_dark}

V _m (R)＝S ₁ (V _gr -V _{g_dark} )*PWM(R)+S ₂ (V _gg -V _{g_dark} )*PWM(G)+

S ₃ (V _gb -V _{g_dark} )*PWM(B)+V _{g_dark}

V _m (R)＝S ₁ (V _br -V _{b_dark} )*PWM(R)+S ₂ (V _bg -V _{b_dark} )*PWM(G)+

S ₃ (V _bb -V _{b_dark} )*PWM(B)+V _{b_dark}

...formula (2)

${\left[\begin{array}{ccc}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; rr</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; PWM</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; r\; g</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; PWM</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; rb</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; PWM</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span>\\ <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; gr</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; PWM</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; gg</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; PWM</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; gb</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; PWM</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span>\\ <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; br</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; PWM</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bg</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; PWM</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& <span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bb</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; PWM</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span>\end{array}\right]}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&times;</span>$

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}\\ {\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}\\ {\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; dark</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{ccc}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}\end{array}\right]$

...formula (3)

Then the calibration unit 61 makes corresponding adjustments to the red, green and blue gamma curves or video data according to the red difference parameter, the green difference parameter and the blue difference parameter, so as to compensate the backlight module 31 caused by temperature or aging. brightness and color distortion.

Those skilled in the art may also change the red sensor 71, the green sensor 72 and the blue sensor 73 into sensors of other colors or quantities according to the spirit of the present invention and the teachings of the aforementioned embodiments, and then adjust the calculation appropriately. The formula of the difference parameter of each color can also realize the compensation of the brightness and color distortion of the backlight module caused by temperature or aging in this way, so it will not be repeated here. The advantage of this method is that brightness compensation can be performed for different color light sources, and appropriate brightness compensation can be performed according to different color light sources due to different aging speeds. In addition, in another embodiment, the red sensor 71 , the green sensor 72 and the blue sensor 73 of the above embodiments can also be integrated into one light color sensor to save space and reduce hardware costs.

FIG. 7 is a structural diagram of a brightness compensation device for a backlight module according to a sixth embodiment of the present invention, please refer to FIG. 7 . In this embodiment, the backlight module 31 , the photo-sensing unit 41 , the computing unit 51 and the calibration unit 61 can refer to the above-mentioned embodiments, and will not be repeated here. It should be noted that, in this embodiment, after the calculation unit 51 calculates the difference parameter, the calculation unit 51 will output the difference parameter to the correction unit 61 and the backlight module 31 . Not only the calibration unit 61 can perform brightness compensation according to the difference parameter, but the backlight module 31 can also perform brightness compensation according to the difference parameter. The advantage of this approach is that the correction unit 61 and the backlight module 31 can be used to perform dual brightness compensation at the same time, so that the brightness compensation of the brightness distortion caused by the temperature and aging of the backlight module can be adjusted more flexibly.

FIG. 8 is a structural diagram of a brightness compensation device for a backlight module according to a seventh embodiment of the present invention, please refer to FIG. 8 . In this embodiment, the backlight module 31 , the photo-sensing unit 41 , the computing unit 51 and the calibration unit 61 can refer to the above-mentioned embodiments, and will not be repeated here. It should be noted that, in this embodiment, the light sensing unit 41 can be measured through the substrate 101 . The substrate 101 is, for example, a polarizer, a glass substrate, a color filter, an alignment film, a liquid crystal panel, or an optical film, etc. . . . In other words, those skilled in the art can configure the photo-sensing unit 41 on any layer of the liquid crystal panel, or configure the photo-sensing unit 41 on any layer of the backlight module 31 according to their needs. That is to say, as long as the light sensing unit 41 can sense the light source emitted by the backlight module 31, the brightness and color distortion of the backlight module 31 caused by aging or temperature can be compensated according to the spirit of the present invention and the above-mentioned embodiments. . In addition, according to the different positions of the light sensing unit 41 , the preset brightness can be adjusted appropriately to facilitate the calculation of the difference parameter, which will not be described in detail here.

In summary, the embodiments of the present invention have at least the following advantages:

1. Use the light sensing unit to sense the light source intensity of the backlight module, and calculate the difference parameter according to the above light source intensity and preset brightness, and then adjust the gamma curve and/or video data according to the difference parameter, so as to reduce the backlight module due to temperature or Brightness and color distortion caused by aging.

2. Integrating the calibration unit into the display drive circuit or integrating the calibration unit and the computing unit into the frequency controller can greatly save hardware costs.

3. Multiple sensors or one light color sensor can simultaneously compensate the brightness and color distortion of the light sources of each color in the backlight module due to temperature or aging.

4. While adjusting the gamma curve and/or video data according to the difference parameters, the backlight module can also perform multiple brightness compensations according to the difference parameters, so that the brightness compensation can be adjusted more flexibly.

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

Claims (16)

1. brightness of backlight module compensation method is applicable to that a display device presents a video signal data, and this luminance compensation method comprises the following steps:

One intensity of light source of this backlight module of sensing;

According to this intensity of light source and default brightness calculation one difference parameter; And

Adjust this video signal data according to this difference parameter.

2. luminance compensation method as claimed in claim 1 also comprises the following steps:

Adjust a gamma curve according to this difference parameter, this gamma curve is in order to the brightness or the colour temperature of this video signal data of conversion image.

3. luminance compensation method as claimed in claim 1 also comprises the following steps:

Adjust the intensity of light source of this backlight module according to this difference parameter.

4. luminance compensation method as claimed in claim 1, wherein the step of the intensity of light source of this backlight module of sensing also comprises:

The intensity of light source by this backlight module of substrate sensing.

5. luminance compensation method as claimed in claim 1 wherein also comprises the following steps: according to this intensity of light source and the step that should preset this difference parameter of brightness calculation

According to a red light source intensity and red default brightness calculation one a red difference parameter;

According to a green light source intensity and green default brightness calculation one a green difference parameter; And

According to a blue-light source intensity and blue default brightness calculation one a blue difference parameter.

6. luminance compensation method as claimed in claim 5, the step of wherein calculating this redness difference parameter, this green difference parameter, this blueness difference parameter also comprises the following steps:

Calculate S according to following formula ₁, S ₂With S ₃, S wherein ₁, S ₂With S ₃Be respectively this redness difference parameter, this green difference parameter, this blueness difference parameter:

${\left[\begin{array}{c}(V_{\mathrm{rr}}-V_{r\_\mathrm{dark}})\mathrm{PWM}\left(R\right),(V_{\mathrm{rg}}-V_{r\_\mathrm{dark}})\mathrm{PWM}\left(G\right),(V_{\mathrm{rb}}-V_{r\_\mathrm{dark}})\mathrm{PWM}\left(B\right)\\ (V_{\mathrm{gr}}-V_{g\_\mathrm{dark}})\mathrm{PWM}\left(R\right),(V_{\mathrm{gg}}-V_{g\_\mathrm{dark}})\mathrm{PWM}\left(G\right),(V_{\mathrm{gb}}-V_{g\_\mathrm{dark}})\mathrm{PWM}\left(B\right)\\ (V_{\mathrm{br}}-V_{b\_\mathrm{dark}})\mathrm{PWM}\left(R\right),(V_{\mathrm{bg}}-V_{b\_\mathrm{dark}})\mathrm{PWM}\left(G\right),(V_{\mathrm{bb}}-V_{b\_\mathrm{dark}})\mathrm{PWM}\left(B\right)\end{array}\right]}^{-1}\&times;$

$\left[\begin{array}{c}{V}_m\left(R\right)-V_{r\_\mathrm{dark}}\\ V_m\left(G\right)-V_{g\_\mathrm{dark}}\\ V_m\left(B\right)-V_{b\_\mathrm{dark}}\end{array}\right]=[S_1,S_2,S_3].$

7. luminance compensation method as claimed in claim 5 wherein also comprises according to the step that this difference parameter is adjusted a gamma curve:

Adjust a red gamma curve according to this redness difference parameter;

Adjust a green gamma curve according to this green difference parameter; And

Adjust a blue gamma curve according to this blueness difference parameter.

8. a brightness of backlight module compensation system is applicable to that a display device presents a video signal data, and this luminance compensating mechanism comprises:

One light sensing unit is used for the intensity of light source of this backlight module of sensing;

One arithmetic element is coupled to this light sensing unit, and this arithmetic element is according to this intensity of light source and default brightness calculation one difference parameter; And

One correcting unit is coupled to this arithmetic element, and this correcting unit is adjusted a gamma curve and/or this video signal data according to this difference parameter, and this gamma curve is in order to the brightness or the colour temperature of this video signal data of conversion image.

9. luminance compensating mechanism as claimed in claim 8, wherein this correcting unit also comprises:

One data mapping unit is coupled to this arithmetic element, to adjust this video signal data according to this difference parameter; And

One gamma unit map is coupled to this data mapping unit, to adjust this gamma curve according to this difference parameter.

10. luminance compensating mechanism as claimed in claim 8, wherein this light sensing unit also comprises:

One sensor is used for this intensity of light source of sensing, and exports an electrical signal;

One signal conversion unit is coupled between this arithmetic element and this sensor, in order to change this electrical signal to offer this arithmetic element.

11. luminance compensating mechanism as claimed in claim 8, wherein this backlight module is adjusted the intensity of light source of this backlight module according to this difference parameter.

12. luminance compensating mechanism as claimed in claim 8, wherein this light sensing unit is by this intensity of light source of substrate sensing.

13. luminance compensating mechanism as claimed in claim 8, wherein this light sensing unit also comprises:

One red light sensor is used for the intensity of light source of sensing based on ruddiness, and exports a red light source intensity and give this arithmetic element;

One green sensor is used for the intensity of light source of sensing based on green glow, and exports a green light source intensity and give this arithmetic element; And

One blue sensor is used for the intensity of light source of sensing based on blue light, and exports a blue-light source intensity and give this arithmetic element.

14. luminance compensating mechanism as claimed in claim 13, wherein this arithmetic element is according to this a red light source intensity and red default brightness calculation one a red difference parameter, this arithmetic element is according to this a green light source intensity and green default brightness calculation one a green difference parameter, and this arithmetic element is according to this a blue-light source intensity and blue default brightness calculation one a blue difference parameter.

15. luminance compensating mechanism as claimed in claim 14, wherein this arithmetic element is calculated S according to following formula ₁, S ₂With S ₃, S wherein ₁, S ₂With S ₃Be respectively this redness difference parameter, this green difference parameter, this blueness difference parameter:

${\left[\begin{array}{c}(V_{\mathrm{rr}}-V_{r\_\mathrm{dark}})\mathrm{PWM}\left(R\right),(V_{\mathrm{rg}}-V_{r\_\mathrm{dark}})\mathrm{PWM}\left(G\right),(V_{\mathrm{rb}}-V_{r\_\mathrm{dark}})\mathrm{PWM}\left(B\right)\\ (V_{\mathrm{gr}}-V_{g\_\mathrm{dark}})\mathrm{PWM}\left(R\right),(V_{\mathrm{gg}}-V_{g\_\mathrm{dark}})\mathrm{PWM}\left(G\right),(V_{\mathrm{gb}}-V_{g\_\mathrm{dark}})\mathrm{PWM}\left(B\right)\\ (V_{\mathrm{br}}-V_{b\_\mathrm{dark}})\mathrm{PWM}\left(R\right),(V_{\mathrm{bg}}-V_{b\_\mathrm{dark}})\mathrm{PWM}\left(G\right),(V_{\mathrm{bb}}-V_{b\_\mathrm{dark}})\mathrm{PWM}\left(B\right)\end{array}\right]}^{-1}\&times;$

$\left[\begin{array}{c}{V}_m\left(R\right)-V_{r\_\mathrm{dark}}\\ V_m\left(G\right)-V_{g\_\mathrm{dark}}\\ V_m\left(B\right)-V_{b\_\mathrm{dark}}\end{array}\right]=[S_1,S_2,S_3].$

16. luminance compensating mechanism as claimed in claim 14, wherein this gamma unit map is adjusted a red gamma curve according to this redness difference parameter, this gamma unit map is adjusted a green gamma curve according to this green difference parameter, and this gamma unit map is adjusted a blue gamma curve according to this blueness difference parameter.

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