CN101290744A - Luminance compensating mechanism and method for backlight module - Google Patents

Abstract

The invention discloses a device and a method for the luminance compensation of a backlight module. The device and the method makes use of a light sensing unit to measure the light source intensity of the backlight module, and calculates a difference parameter according to the light source intensity and preset luminance; then, a gamma curve, video data or the light source intensity of the backlight module are adjusted according to the difference parameter so as to reduce the influence on display quality due to the changes of the backlight module caused by temperature or aging.

Description

Brightness of backlight module compensation system and method

Technical field

The present invention relates to a kind of brightness of backlight module compensation system, particularly relate to a kind of brightness that utilizes the light sensing technology to come the compensate for backlight module.

Background technology

Along with the progress of science and technology, LCD (Liquid Crystal Display is called for short LCD) is also day by day popularized.Yet LCD can wear out along with service time, and is wherein especially obvious with the backlight liquid crystal display module again.Some backlight module mainly is to provide light source by light emitting diode (Light-EmittingDiode is called for short LED).The light intensity that light emitting diode sent can change to some extent because of wearing out of temperature and assembly.In order to make LCD can present stable brightness and color, therefore aging along with backlight module must compensate at the color and the brightness of backlight module.

Fig. 1 is the Organization Chart of known a kind of brightness of backlight module compensation system, please refer to Fig. 1.Comprising power supply changeover device 10, backlight driving unit 20, light emitting diode 30, light sensing unit 40 and control module 50.Wherein power supply changeover device 10 is in order to provide backlight driving unit 20 required voltage.Backlight driving unit 20 is in order to provide light emitting diode 30 required voltage and electric current.30 variations according to voltage and electric current of light emitting diode produce the corresponding intensity of light source.Then utilize light sensing unit 40 to detect light emitting diode 30 light intensity that sends and also transmit the detection signal to control module 50.50 of control modules are adjusted backlight driving unit 20 according to the detection signal and are adjusted light emitting diode 30 to reach feedback.Realize the brightness of backlight module compensation by this.

In addition, United States Patent (USP) also proposes the similar above-mentioned practice the 6127783rd, 6344641,6441558,6448550,6495964, No. 6894442, and its difference is the sequential that drives, the position that light sensing unit 40 is placed, kind of optical sensor or the like.It should be noted that the above-mentioned practice is all by the brightness of control module 50 according to the brilliance control light emitting diode 30 of 40 sensings of light sensing unit.Not only need the ancillary cost cost to increase control module 50, the effect of the brightness of adjustment light emitting diode 30 is also quite limited.

In view of this, suitable settling mode is eager to seek in the relevant manufacturer of LCD, to overcome above-mentioned problem.

Summary of the invention

The invention provides a kind of brightness of backlight module compensation method, by the light emitting diode of adjusting video signal data compensate for backlight module because of wearing out or the brightness that temperature caused or the distortion of color.

The invention provides a kind of brightness of backlight module compensation system, utilize the intensity of light source of light sensing unit sensing backlight module, and then try to achieve the intensity of light source of backlight module and the difference parameter of default brightness, and then adjust video signal data to promote display quality.

The present invention proposes a kind of brightness of backlight module compensation method, is applicable to that display device presents video signal data, and this luminance compensation method comprises the following steps.The sensing backlight module the intensity of light source.According to the above-mentioned intensity of light source and default brightness calculation difference parameter.Adjust video signal data according to difference parameter.

In one embodiment of this invention, above-mentioned luminance compensation method also comprises according to difference parameter adjusts gamma curve, and this gamma curve is in order to the brightness of conversion image video signal data.

The present invention proposes another kind of brightness of backlight module compensation system, is applicable to that display device presents video signal data, and this luminance compensating mechanism comprises light sensing unit, arithmetic element and correcting unit.Light sensing unit is used for the intensity of light source of sensing backlight module.Arithmetic element is coupled to light sensing unit, and this arithmetic element is according to the above-mentioned intensity of light source and default brightness calculation difference parameter.Correcting unit is coupled to arithmetic element, and this correcting unit is adjusted gamma curve and/or video signal data according to difference parameter, and this gamma curve is in order to the brightness of conversion image video signal data.

In one embodiment of this invention, above-mentioned luminance compensating mechanism, wherein correcting unit also comprises data mapping unit and gamma unit map.The data mapping unit is coupled to arithmetic element, and video signal data is adjusted according to difference parameter in this data mapping unit.The gamma unit map is coupled to the data mapping unit, and this gamma unit map is adjusted gamma curve according to difference parameter.

In one embodiment of this invention, above-mentioned luminance compensating mechanism, wherein light sensing unit also comprises sensor and signal conversion unit.Sensor is used for the above-mentioned intensity of light source of sensing.Signal conversion unit is coupled between arithmetic element and the sensor, and this signal conversion unit converts digital signal in order to the analog signal with sensor institute sensing.

The present invention is because of utilizing the intensity of light source of light sensing unit sensing backlight module, and according to the above-mentioned intensity of light source and default brightness calculation difference parameter, adjust gamma curve and/or video signal data according to difference parameter again, use and reduce backlight module Yin Wendu or aging and luminance distortion that cause.

For above-mentioned feature and advantage of the present invention can be become apparent, preferred embodiment cited below particularly, and be described with reference to the accompanying drawings as follows.

Description of drawings

Fig. 1 is the Organization Chart of known a kind of brightness of backlight module compensation system.

Fig. 2 A is a kind of brightness of backlight module compensation system Organization Chart according to the first embodiment of the present invention.

Fig. 2 B is a kind of brightness of backlight module compensation method process flow diagram according to the first embodiment of the present invention.

Fig. 3 is a kind of brightness of backlight module compensation system Organization Chart according to the second embodiment of the present invention.

Fig. 4 is a kind of brightness of backlight module compensation system Organization Chart according to the third embodiment of the present invention.

Fig. 5 is a kind of brightness of backlight module compensation system Organization Chart according to the fourth embodiment of the present invention.

Fig. 6 is a kind of brightness of backlight module compensation system Organization Chart according to the fifth embodiment of the present invention.

Fig. 7 is a kind of brightness of backlight module compensation system Organization Chart according to the sixth embodiment of the present invention.

Fig. 8 is a kind of brightness of backlight module compensation system Organization Chart according to the seventh embodiment of the present invention.

The reference numeral explanation

10: power supply changeover device

20: backlight driving unit

30: light emitting diode

31: backlight module

40,41,42,43: light sensing unit

50: control module

51: arithmetic element

61,62: correcting unit

70: sensor

71: red light sensor

72: green sensor

73: blue sensor

80: signal conversion unit

91: the data mapping unit

92: the gamma unit map

93: time schedule controller

94: the display driver circuit

101: substrate

S201～S203: each step that is Fig. 2 B process flow diagram

Embodiment

Fig. 2 A is a kind of brightness of backlight module compensation system Organization Chart according to the first embodiment of the present invention, and Fig. 2 B is a kind of brightness of backlight module compensation method process flow diagram according to the first embodiment of the present invention, please refer to Fig. 2 A and Fig. 2 B.Luminance compensating mechanism has comprised light sensing unit 41, arithmetic element 51, correcting unit 61, and this luminance compensating mechanism is suitable for the brightness with the backlight module 31 of compensation display device.The backlight of backlight module 31 then sends corresponding light according to voltage and electric current.In addition, at this embodiment, the backlight of backlight module 31 illustrates present embodiment as an example with the light emitting diode of RGB (Red Green Blue is called for short RGB) especially.Those skilled in the art should understand, " light emitting diode of RGB " that present embodiment is given an example only is a specific embodiment, in another embodiment, the backlight of backlight module 31 still can use the light emitting diode collocation optical filter of cold cathode fluorescent lamp, white light to come colour mixture or use the pointolite of other form, line source, area source or the like ..., so the present invention should not be defined in this kind specific embodiment.

Follow by step S201 the intensity of light source of light sensing unit 41 sensing backlight modules 31.Follow execution in step S202, by the intensity of light source and the default brightness calculation difference parameter of arithmetic element 51 according to above-mentioned sensing.Default referred in this brightness be backlight module 31 should export ideal expectation brightness.Execution in step S203 again adjusts video signal data and/or gamma curve by correcting unit 61 according to difference parameter at last, and wherein gamma curve is in order to the brightness of conversion image video signal data.Like this practice, not only can compensate for backlight module 31 because of temperature or the aging luminance distortion that is caused, also can reduce the distortion of color.The described correcting unit 61 of present embodiment is adjusted gamma curve according to difference parameter, and those skilled in the art also can change embodiment according to its demand, for example presets many gamma curves, and 61 of correcting units are selected gamma curve for use according to difference parameter.

Fig. 3 is a kind of brightness of backlight module compensation system Organization Chart according to the second embodiment of the present invention, please refer to Fig. 3.In this embodiment, luminance compensating mechanism comprises light sensing unit 42, arithmetic element 51 and correcting unit 61.Wherein arithmetic element 51 is same as the previously described embodiments with correcting unit 61, does not repeat them here.It should be noted that light sensing unit 42.In the present embodiment, light sensing unit 42 has comprised sensor 70 and signal conversion unit 80.Sensor 70 is in order to the intensity of light source and the output electric property signal of sensing backlight module 31.In the present embodiment, the electrical signal that sensor 70 is exported is an analog signal, for example is voltage or electric current.

Sensor 70 can have different kenel according to different embodiment, for example sensor 70 can be optical diode (Photodiode), photochromic color sensor (Color Sensor) or peripheral optical sensor (Ambient Light Sensor, be called for short ALS) or the like, in other words, sensor 70 is made a general reference the photosensory assembly with the function that detects light.

Signal conversion unit 80 is coupled between arithmetic element 51 and the sensor 70.(Serial Peripheral Interface, SPI) or between integrated circuit (Inter-Integrated Circuit, IIC) interface transmits data can to utilize sequence transmission interface between signal conversion unit 80 and the sensor 70.The electrical signal that signal conversion unit 80 is then provided in order to conversion sensor 70, for example signal conversion unit 80 analog signal (voltage or electric current) that sensor 70 is provided transfers digital signal in the present embodiment.Moreover, signal conversion unit 80 also can be adjusted sampling frequency according to its demand.Then send digital signal to arithmetic element 51 by signal conversion unit 80 again.Arithmetic element 51 is then according to digital signal and default brightness calculation difference parameter, adjust gamma curve and/or video signal data by correcting unit 61 according to difference parameter again, the practice like this, not only can compensate for backlight module 31 because of temperature or the aging luminance distortion that is caused, also can reduce the distortion of color.

Though the electrical signal that sensor 70 is exported in the foregoing description is example with the analog signal, in other embodiments, sensor 70 also can directly be exported digital signal.Thus, 70 of sensors can directly offer arithmetic element 51 and carry out computing.In addition, signal conversion unit 80 is not only can transfer analog signal to digital signal yet, and for example in the middle of specific embodiments, signal conversion unit 80 also can transfer voltage signal to current signal or transfer current signal to voltage signal.Therefore, those skilled in the art can determine the signal kind that signal conversion unit 80 is changed according to its demand.

Fig. 4 is a kind of brightness of backlight module compensation system Organization Chart according to the third embodiment of the present invention, please refer to Fig. 4.In the present embodiment, luminance compensating mechanism comprises light sensing unit 41, arithmetic element 51 and correcting unit 62.Wherein light sensing unit 41 is same as the previously described embodiments with arithmetic element 51, does not repeat them here.It should be noted that correcting unit 62.In the present embodiment, correcting unit 62 has comprised data mapping unit 91 and gamma unit map 92.Data mapping unit 91 is coupled to arithmetic element 51, and the difference parameter that this data mapping unit 91 is calculated according to arithmetic element 51 is adjusted video signal data.Data mapping unit 91 for example is to adjust video signal data in the mode of digital revolution word (Digital to Digital).More particularly, correcting unit 62 can provide digitized dynamic gamma curve to data mapping unit 91 according to difference parameter.91 brightness of adjusting video signal data with the gamma curve of memory mapping (MemoryMapping) in data mapping unit.

Gamma unit map 92 is coupled to data mapping unit 91.It should be noted that gamma unit map 92 can adjust gamma curve according to difference parameter equally.In particular, gamma unit map 92 for example can be preset many gamma curves, and selects different gamma curves for use according to difference parameter, uses the brightness of adjusting video signal data.What deserves to be mentioned is, though present embodiment uses data mapping unit 91 and gamma unit map 92 to adjust the brightness of video signal data simultaneously.After correcting unit 62 received the difference parameter that arithmetic elements 51 calculate, one of them adjusted video signal data also can only to utilize data mapping unit 91 and gamma unit map 92 but in another embodiment.Like this practice, not only can compensate for backlight module 31 because of temperature or the aging luminance distortion that is caused, also can reduce the distortion of color.

Fig. 5 is a kind of brightness of backlight module compensation system Organization Chart according to the fourth embodiment of the present invention, please refer to Fig. 5.Backlight module 31 among Fig. 5, light sensing unit 41, arithmetic element 51, correcting unit 62, data mapping unit 91 and gamma unit map 92 are same as the previously described embodiments, do not repeat them here.In the present embodiment, after correcting unit 62 finished video signal data according to the difference parameter adjustment, correcting unit 62 sent adjusted video signal data to time schedule controller (Timing Controller orTiming Generator) 93.Time schedule controller 93 is used for producing the required controlling signal and the data signals of each driver circuit of display device.In other words, with correcting unit 62 be disposed at time schedule controller 93 before, time schedule controller 93 can be according to adjusted video signal data output controlling signal and adjusted video signal data to display driver circuit 94.94 of display driver circuits present adjusted video signal data in order to drive display device, luminance distortion that so can compensate for backlight module 31.Display driver circuit 94 general reference source electrode drive circuits (Source Driver IntegratedCircuit), the relative application circuit of gate driver circuit (Gate Driver Integrated Circuit) in the present embodiment.

As above above-mentioned, also visual its demand of those skilled in the art, and change embodiment according to the teaching of spirit of the present invention and aforementioned all embodiment.For example in another embodiment, correcting unit 62 is also configurable behind time schedule controller 93.In other words correcting unit 62 can be integrated in display driver circuit 94 in, for example data mapping unit 91 is integrated in the source electrode drive circuit.For example gamma unit map 92 is integrated in again in the source electrode drive circuit or the like ....The benefit of this practice is not need additionally to set up new hardware structure, utilizes existing display device framework, gets final product compensate for backlight module 31 because of temperature or the aging brightness that is caused and the distortion of color, has reduced hardware cost significantly.

Fig. 6 is a kind of brightness of backlight module compensation system Organization Chart according to the fifth embodiment of the present invention, please refer to Fig. 6.In the present embodiment, luminance compensating mechanism has comprised light sensing unit 43, arithmetic element 51 and correcting unit 61.Light sensing unit 43 has comprised red light sensor 71, green sensor 72, blue sensor 73 and signal conversion unit 80.Wherein arithmetic element 51, correcting unit 61 can not repeat them here with reference to above-mentioned all embodiment with signal conversion unit 80.It should be noted that red light sensor 71, green sensor 72 and blue sensor 73.Red light sensor 71 is used for the intensity of light source based on ruddiness of sensing backlight module 31, and gives arithmetic element 51 by the signal conversion unit 80 output red intensities of light source.Green sensor 72 is used for the intensity of light source based on green glow of sensing backlight module 31, and gives arithmetic element 51 by signal conversion unit 80 output green light source intensity.Blue sensor 73 is used for the intensity of light source based on blue light of sensing backlight module 31, and gives arithmetic element 51 by the signal conversion unit 80 output blue intensities of light source.

As mentioned above, utilize following formula (1), (2) can push away formula (3).Arithmetic element 51 again according to following formula (3) calculate red difference parameter, green difference parameter and blue difference parameter, the explanation of formula (1)～(3) can with reference under tabulate one.

V (R), V (G), V (B)	The blue-light source intensity that the red light source intensity that default red light sensor 71 is sensed, the green light source intensity that green sensor 72 is sensed and blue sensor 73 are sensed.
		V m(R), V m(G), V m(B)	After factors such as aging or temperature variation produce, the blue-light source intensity that the red light source intensity that this moment, red light sensor 71 was sensed, the green light source intensity that green sensor 72 is sensed and blue sensor 73 are sensed.
V Rr, V Gr, V Br	Use the continual driving red light emitting diodes of fixed drive electric current, the blue-light source intensity that the red light source intensity that this moment, red light sensor 71 was sensed, the green light source intensity that green sensor 72 is sensed and blue sensor 73 are sensed.
		V Rg, V Gg, V Bg	Use the continual driving green LED of fixed drive electric current, the red light source intensity that this moment, red light sensor 71 sensed, green light source intensity and the blue sensor 73 that green sensor 72 sensed sense

	Blue-light source intensity.
		V Rb, V Gb, V Bb	Use the continual driving blue LED of fixed drive electric current, the blue-light source intensity that the red light source intensity that this moment, red light sensor 71 was sensed, the green light source intensity that green sensor 72 is sensed and blue sensor 73 are sensed.
V R_dark, V G_dark, V B_dark	When red light emitting diode, green LED and blue LED are all turned off, the blue-light source intensity that the red light source intensity that this moment, red light sensor 71 was sensed, the green light source intensity that green sensor 72 is sensed and blue sensor 73 are sensed.
		PWM (R)	Lighting the time cycle that time/red light emitting diodes is lighted of default red light emitting diodes
PWM (G)	Lighting the time cycle that time/green LED is lighted of default green LED
		PWM (B)	Lighting the time cycle that time/blue LED is lighted of default blue LED
S 1	Red difference parameter
		S 2	Green difference parameter
S 3	Blue difference parameter

Table one: the explanation of formula (1)～(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)

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

$\left[\begin{array}{c}{V}_m\left(R\right)-V_{r\_\mathrm{dark}}\\ V_m\left(G\right)-V_{g\_\mathrm{dark}}\\ V_m\left(B\right)-V_{b\_\mathrm{dark}}\end{array}\right]=\left[\begin{array}{ccc}{S}_1,& S_2,& S_3\end{array}\right]$

... formula (3)

Then correcting unit 61 is done corresponding adjustment to red, green with blue gamma curve or video signal data respectively according to red difference parameter, green difference parameter and blue difference parameter again and is got final product compensate for backlight module 31 because of temperature or the wear out brightness that caused and the distortion of color.

Also visual its demand of those skilled in the art, and the teaching of foundation spirit of the present invention and aforementioned all embodiment makes red sensor 71, green sensor 72 and blue sensor 73 into the sensor of other color or quantity, suitably adjust the formula of the difference parameter of calculating each color again, so also can realize compensate for backlight module Yin Wendu or the aging brightness that is caused and the distortion of color, then will not give unnecessary details at this.So the benefit of the practice is and can carries out luminance compensation at light sources of different colors, can carry out the appropriate brightness compensation because of aging speed is different along with light sources of different colors.In addition, in another embodiment, also the red sensor 71 of the foregoing description, green sensor 72 can be incorporated into a photochromic color sensor with blue sensor 73 and use the saving space, and reduce hardware cost.

Fig. 7 is a kind of brightness of backlight module compensation system Organization Chart according to the sixth embodiment of the present invention, please refer to Fig. 7.In the present embodiment, backlight module 31, light sensing unit 41, arithmetic element 51 can not repeat them here with reference to above-mentioned all embodiment with correcting unit 61.It should be noted that in the present embodiment after arithmetic element 51 calculated difference parameter, arithmetic element 51 can be exported to difference parameter correcting unit 61 and backlight module 31.Not only correcting unit 61 can carry out luminance compensation according to difference parameter, and backlight module 31 also can carry out luminance compensation according to difference parameter.So the benefit of the practice is to utilize simultaneously correcting unit 61 and backlight module 31 to carry out the dual brightness compensation, allows the backlight module Yin Wendu and the luminance compensation of the aging luminance distortion that is caused have more the elasticity adjustment.

Fig. 8 is a kind of brightness of backlight module compensation system Organization Chart according to the seventh embodiment of the present invention, please refer to Fig. 8.In the present embodiment, backlight module 31, light sensing unit 41, arithmetic element 51 can not repeat them here with reference to above-mentioned all embodiment with correcting unit 61.It should be noted that in the present embodiment light sensing unit 41 can measure by substrate 101.Substrate 101 for example is Polarizer, glass substrate, colored filter, alignment film, liquid crystal panel or blooming piece or the like ....In other words, those skilled in the art can be disposed at any one deck in the liquid crystal panel with light sensing unit 41 according to its demand, or light sensing unit 41 is disposed at any one deck in the backlight module 31.That is to say,, can come compensate for backlight module 31 because of brightness and color distortion aging or that temperature caused according to spirit of the present invention and above-mentioned all embodiment as long as light sensing unit 41 can sense the light source that backlight module 31 is sent.The position difference of putting at light sensing unit 41 can suitably be adjusted default brightness in addition, is beneficial to the calculated difference parameter, then will not give unnecessary details at this.

In sum, embodiments of the invention have following advantage at least:

1. utilize the intensity of light source of light sensing unit sensing backlight module, and according to the above-mentioned intensity of light source and default brightness calculation difference parameter, adjust gamma curve and/or video signal data according to difference parameter again, use and reduce backlight module Yin Wendu or aging and brightness and color distortion that cause.

2. correcting unit is integrated into the display driver circuit or correcting unit and arithmetic element are integrated into frequency controller and can significantly save hardware cost.

3. by light source Yin Wendu or the aging brightness that causes and the distortion of color of each color in the compensate for backlight module simultaneously of a plurality of sensors or photochromic color sensor.

4. when adjusting gamma curve and/or video signal data according to difference parameter, backlight module also can carry out the multiple compensation of brightness simultaneously according to difference parameter, make luminance compensation have more the elasticity adjustment.

Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; any one of skill in the art; can do some changes and retouching under the premise without departing from the spirit and scope of the present invention, so protection scope of the present invention is as the criterion with claim 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:

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

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

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:

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

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

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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