CN1432988A - Gamma correcting device and method for LCD - Google Patents
Gamma correcting device and method for LCD Download PDFInfo
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- CN1432988A CN1432988A CN 02102023 CN02102023A CN1432988A CN 1432988 A CN1432988 A CN 1432988A CN 02102023 CN02102023 CN 02102023 CN 02102023 A CN02102023 A CN 02102023A CN 1432988 A CN1432988 A CN 1432988A
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Abstract
The gamma correcting device for LCD incluces at least pixel data converting unit to output pixel converting data based on pixel data; and gamma correction unit to output gamma voltage based on pixel converting data, with the gamma voltage range varying with the color displayed by the pixel. Each of the pixel data is one M-bit data and each of the pixel converting data is one N-bit data, with N being greater than M. The coibncidence relation between the pixel data and pixel converting data for different colors and gamma voltage is established in the gamma correcting device in advance, and the coincidence relation between the pixel converting data and the gamma voltages is used to provide gramma voltages corresponding to three different colors.
Description
Invention field
The present invention is relevant for a kind of digital analogue signal conversion equipment and method, particularly relevant for a kind of gamma (γ) means for correcting and method that is used for LCD.
Background of invention
Because LCD (LCD) has the advantage of thin, the in light weight and low electromagnetic of volume, is widely used gradually in recent years.
Please refer to Fig. 1, it illustrates the graph of a relation of the light transmission (light transmissivity) of the upper plate of liquid crystal panel and institute's making alive between lower plate and liquid crystal molecule.The light transmission of liquid crystal molecule is not linear between institute's making alive of the upper plate of LCD and lower plate and two plates, but the relation of gamma curve as shown in Figure 1.Wherein, the institute's making alive between upper plate and lower plate is called gamma electric voltage.In addition, the light transmission of liquid crystal molecule is only relevant with the size of gamma electric voltage, and irrelevant with the polarity of gamma electric voltage.Therefore, gamma curve is for being the center with the ordinate, and the gamma curve 104 of symmetrical positive polarity gamma curve 102 and negative polarity synthesizes.Be noted that in the gamma curve 104 of positive polarity gamma curve 102 and negative polarity, the stage casing part of curve is approximately straight line, and the value of slope is bigger.The leading portion of curve and back segment part then are nonlinear curve, and the value of slope is less.
If import identical but the gamma electric voltage that polarity is different of two values respectively, then the liquid crystal molecule of this pixel has identical light transmission.For LCD, if the voltage of the same polarity of each pixel of sustainable supply, with the damage of the liquid crystal molecule that causes pixel.Therefore, can protect the liquid crystal molecule of pixel by the polarity of the gamma electric voltage that alternatively changes the input liquid crystal panel.
Please refer to Fig. 2, it illustrates the calcspar of non-linear, digital analog conversion circuit (DAC) 202.General pixel data is the binary data of digital form.In the driving circuit of LCD, has a non-linear, digital analog conversion circuit 202.Non-linear, digital analog conversion circuit 202 converts corresponding gamma electric voltage OUT to the pixel data DATA with digital format, is used for controlling the light transmission of certain pixel liquid crystal molecule on the liquid crystal panel, makes this pixel produce different brightness.
Please refer to Fig. 3, it illustrates the graph of a relation of the light transmission of desirable pixel data DATA and liquid crystal molecule.Described by preamble, the gamma electric voltage of input liquid crystal panel and the light transmission of liquid crystal molecule are the gamma curve relation.Therefore, when non-linear, digital analog conversion circuit 202 converts the pixel data DATA of digital format to gamma electric voltage signal OUT input liquid crystal panel, need carry out gamma correction (Gamma correction), make the light transmission of pixel data DATA and liquid crystal molecule linear.So, so that the display frame of LCD has preferable image display quality.
Please refer to Fig. 4 A～4C, it illustrates the synoptic diagram that non-linear, digital analog conversion circuit 202 is carried out gamma correction.The gamma curve graph of a relation of Fig. 4 A remarked pixel data DATA and gamma electric voltage OUT.In Fig. 4 A, gamma curve comprises the gamma curve 402 of positive polarity and the gamma curve 404 of negative polarity.Before carrying out gamma correction operation, at first, on the gamma curve 404 of the gamma curve 402 of positive polarity and negative polarity, take out 5 specified point A, B, C, D and E respectively, and A ', B ', C ', D ', with E '.With the pairing gamma electric voltage V0 of these a little specified points, V1, V2, V3 and V4, and V9, V8, V7, V6 and V5 are as the sampling voltage signal GMV of input non-linear, digital analog conversion circuit 202.General pixel data DATA is eight a binary data, can represent 256 gray levels (graylevel) altogether.General pixel data DATA is eight a binary format, in Fig. 4 A.Selected pixel data DATA can decade be expressed as 0,63,127,191 and 255 respectively.Wherein, because the size of gamma electric voltage and pixel data is the gamma curve relation, when being shown in selected pixel data DATA on the illustrated abscissa, the interval of two pixel data DATA is identical, but it distinguishes corresponding gamma electric voltage OUT interval each other and inequality.Adjacent in twos gamma electric voltage OUT is the change to some extent along with the position on gamma curve at the interval on the ordinate.And because the stage casing part and the slope of gamma curve is bigger, so at the middle section position of gamma curve, adjacent gamma electric voltage signal OUT interval to each other is less.And because the leading portion and the back segment part slope of gamma curve is less, so in the position of the leading portion and the back segment of gamma curve, adjacent gamma electric voltage signal OUT interval to each other is bigger.For example: in positive polarity gamma curve 402, the interval between V7 and the V8 is littler than the interval between V5 and V6 or V8 and the V9.And in negative polarity gamma curve 404, the interval between V1 and the V2 is littler than the interval between V0 and V1 or V3 and the V4.
Non-linear simulation converting unit 202 has two groups of gamma voltage follower circuits that formed by a plurality of resistance serial connections.Import corresponding specific gamma electric voltage V0～V9 respectively in the specific endpoints of two groups of resistance.Suitably set the resistance value of each resistance in two groups of resistance according to the gamma curve of Fig. 4 A, according to the law of partial pressure, can be in the node output and 256 corresponding 256 gamma electric voltage OUT of pixel data DATA of two groups of resistance.Please refer to Fig. 4 B, it illustrates the gamma curve graph of a relation of the light transmission of the gamma electric voltage OUT of output non-linear, digital analog conversion circuit 202 and pixel liquid crystal molecule.By the relation of the light transmission of previously described gamma electric voltage OUT and liquid crystal molecule as can be known, size is identical but gamma electric voltage V0 and V9, V1 and V8, V2 and V7, V3 and V6, V4 and V5 that polarity is different have the light transmission of T0, T1, T3 and T4 to make liquid crystal molecule respectively.Please refer to Fig. 4 C, it illustrates the graph of a relation of the light transmission of pixel data DATA and liquid crystal molecule.Non-linear, digital analog conversion circuit 202 is carried out gamma correction, makes each pixel data DATA all have corresponding gamma electric voltage signal OUT, and with its input liquid crystal panel.So, so that the light transmission of pixel data DATA and liquid crystal molecule is linear, make the display frame of LCD have preferable image display quality.
In colour liquid crystal display device, each visualization unit is made up of three pixels.Wherein, each pixel can show one of Red Green Blue respectively.Please refer to Fig. 5 A～5C, three gamma curves that indicate R, G, B among the figure are represented when the pixel demonstration is red, green and blue the corresponding relation of the gamma electric voltage of liquid crystal panel and the light transmission of liquid crystal molecule respectively.Fig. 5 A～5C only indicates the gamma curve when gamma electric voltage is negative polarity.And by Fig. 5 A～5C as can be known, when pixel showed different colours, its gamma curve was also inequality.In addition, show redness, blueness respectively, when green, make the light transmission of liquid crystal molecule reach maximum gamma electric voltage and be respectively V when pixel
RM, V
BMAnd V
GM, its magnitude of voltage size is in regular turn: V
BM＜V
GM＜V
RM
Please refer to Fig. 5 A, it illustrates tradition and shows that to being used to blue pixels data DATA carries out the synoptic diagram of the light transmission of gamma correction gained gamma electric voltage and liquid crystal molecule.Tradition non-linear, digital analog converter is when carrying out the gamma correction operation, and the gamma curve when showing blueness with pixel is as the criterion, the corresponding relation of decision pixel data DATA and gamma electric voltage OUT.So set when pixel shows blueness, make the light transmission of liquid crystal molecule reach maximum gamma electric voltage V
BMThe maximal value of the gamma electric voltage OUT that is exported for non-linear, digital analog-converted unit 202.Afterwards, be benchmark with gamma electric voltage VBM again, according to the gamma curve when pixel shows blueness, decide all pixel data DATA to be distinguished corresponding gamma electric voltage OUT by non-linear, digital analog conversion circuit 202.Representing to be respectively 0,63,127,191 and 255 pixel data DATA with size with decade is example, and then its pairing gamma electric voltage OUT is respectively V0, V1, V2, V3 and V
BMIn other words, no matter which kind of color pixel data DATA is used to show when tradition is carried out gamma correction, pixel data DATA all corresponds to fixing gamma electric voltage OUT, and the maximal value 255 pairing gamma electric voltage OUT of pixel data DATA are V
BM
The shortcoming of the mode of decision pixel data DATA mentioned above and the corresponding relation of gamma electric voltage OUT is: please refer to Fig. 5 B and Fig. 5 C, it represents to use tradition to show that to being used to green and red pixel data DATA carry out the synoptic diagram of the light transmission of gamma correction gained gamma electric voltage and liquid crystal molecule respectively.The tradition gamma correction method shows that to being used to green and red pixel data DATA carry out gamma correction to be used to show the corresponding relation of blue pixels data DATA and gamma electric voltage OUT.For example: by preamble as can be known, when pixel shows blueness, gamma electric voltage V0, V1, V2, V3 and V
BMPairing pixel data DATA becomes an arithmetic progression in regular turn.But the gamma curve when gamma curve when the pixel demonstration is red or green and pixel show blueness is also inequality.So when the pixel demonstration is green or red, the light transmission T0～T4 of its pairing liquid crystal molecule, when being shown in it on illustrated ordinate, interval each other can't be identical, shown in Fig. 5 B and Fig. 5 C.In other words, show that to being used to redness or green pixel data DATA carry out gamma correction if show with pixel that gamma curve when blue is as the criterion, the light transmission of pixel data DATA and liquid crystal molecule can't be linear.
In addition, be used for showing when green or red the maximal value V of the gamma electric voltage OUT of input pixel when pixel
BMCan't make liquid crystal molecule have maximum light transmission T
MAX, shown in Fig. 5 B and Fig. 5 C.
Because traditional gamma correction method has above-mentioned shortcoming, so can't make LCD present best image display quality.
Summary of the invention
Therefore, the purpose of this invention is to provide a kind of gamma correcting device and method that is used for LCD, the pixel that can make LCD can both have best image display quality when showing different colors.
According to purpose of the present invention, a kind of gamma correcting device and method that is used for LCD proposed, be used for pixel data is converted to corresponding gamma electric voltage, input in the pixel again.Gamma correcting device comprises pixel data converting unit and gammate at least.The pixel data converting unit is converted to the conversion pixel data according to the corresponding relation of built-in in advance pixel data with the conversion pixel data with pixel data.Wherein, pixel data is the binary data of M position, and the conversion pixel data is the binary data of N position, and M, N are all positive integer, and M is less than N.Gammate will be changed pixel data and be converted to corresponding gamma electric voltage according to the built-in in advance conversion pixel data and the corresponding relation of gamma electric voltage.Wherein, and different, the gamma electric voltage magnitude range of output gamma correcting device is also different with the shown color of pixel with the shown color of pixel for the corresponding relation between pixel data and conversion pixel data and the gamma electric voltage.And the corresponding relation of conversion pixel data and gamma electric voltage is used to provide demonstration three kinds of pairing gamma electric voltages of different colours.
For above-mentioned purpose of the present invention, feature and advantage can be become apparent, a preferred embodiment cited below particularly, and cooperate appended accompanying drawing to be described in detail as follows.
Description of drawings
Fig. 1 represents the graph of a relation of the light transmission of the upper plate of liquid crystal panel and institute's making alive between lower plate and liquid crystal molecule.
Fig. 2 represents the calcspar of non-linear, digital analog-converted unit.
The graph of a relation of the light transmission of Fig. 3 remarked pixel data and liquid crystal molecule.
The gamma curve graph of a relation of Fig. 4 A remarked pixel data and gamma electric voltage.
Fig. 4 B represents to export the gamma curve graph of a relation of the light transmission of the gamma electric voltage of non-linear, digital analog conversion circuit and pixel liquid crystal molecule.
The graph of a relation of the light transmission of Fig. 4 C remarked pixel data and liquid crystal molecule.
Fig. 5 A represents that tradition carries out the synoptic diagram of the light transmission of gamma correction gained gamma electric voltage and liquid crystal molecule to being used to show the blue pixels data.
Fig. 5 B represents that tradition shows that to being used to green pixel data carries out the synoptic diagram of the light transmission of gamma correction gained gamma electric voltage and liquid crystal molecule.
Fig. 5 C represents that tradition shows that to being used to red pixel data carries out the synoptic diagram of the light transmission of gamma correction gained gamma electric voltage and liquid crystal molecule.
Fig. 6 represents the circuit block diagram of gamma correcting device proposed by the invention.
Fig. 7 represents to carry out as the gamma correcting device of Fig. 6 the process flow diagram of gamma correction operation.
Fig. 8 represents that the present invention shows that to being used to red pixel data carries out the synoptic diagram of the light transmission of gamma correction gained gamma electric voltage and liquid crystal molecule.
Fig. 9 A～9B represents to illustrate pixel data and the corresponding relation figure that changes pixel data.
The circuit block diagram of Figure 10 remarked pixel Date Conversion Unit.
Figure 11 represents the circuit block diagram of gammate.
The drawing reference numeral explanation
102,402: the positive polarity gamma curve
104,404: the negative polarity gamma curve
202: the non-linear, digital analog conversion circuit
602: gamma correcting device
604: the pixel data converting unit
606: gammate
1002: the pixel data conversion memory unit
1004: pixel data conversion corresponding unit
1102: the gamma correction storage unit
1104: the gamma correction corresponding unit
Embodiment
Design of the present invention is: the corresponding relation of pixel data and gamma electric voltage is stored in the gamma correcting device in advance with the form of changing corresponding tables (look up table).And be used to show the pixel data of different colours, its pairing gamma electric voltage is also inequality.Wherein, the corresponding relation of pixel data and gamma electric voltage and the magnitude range of gamma electric voltage are along with pixel data is used for the color of demonstration and different.
Please refer to Fig. 6, it illustrates the circuit block diagram of the gamma correcting device 602 that present embodiment proposes.Gamma correcting device 602 is arranged in the driving circuit of LCD, is used to replace the function of traditional non-linear, digital analog-converted unit, and pixel data DATA is converted to corresponding gamma electric voltage OUT output.Wherein, gamma correcting device 602 is coupled by pixel data converting unit 604 and gammate 606 and forms.
Please refer to Fig. 7, it illustrates the process flow diagram of carrying out the gamma correction operation as the gamma correcting device 602 of Fig. 6.Gamma correction operation proposed by the invention comprises the following steps: at least
At first, carry out step 702, in pixel data DATA input gamma correcting device 602.Wherein, pixel data DATA is an example with eight binary data, can represent 256 kinds of different GTGs (gray level) value at most.
Afterwards, execution in step 704, pixel data switch process.Described by preamble, when pixel shows redness, green and the gamma curve when blue and inequality respectively.Therefore, the present invention's foundation and the color that pixel data DATA is used to show are carried out different gamma correction operations.Gamma correction operation of the present invention is divided into two steps, and at first, pixel data converting unit 704 according to the shown color of corresponding pixel, is converted into corresponding conversion pixel data TDATA earlier with pixel data DATA.Wherein, pixel data DATA is stored in the pixel data converting unit 604 with the form of changing corresponding tables (look uptable) in advance with the corresponding relation of conversion pixel data TDATA, and the corresponding relation between pixel data DATA and the conversion pixel data TDATA decides with the color that pixel data DATA is used for demonstration.
Referring again to Fig. 5 A～5C, for being used to show redness and green pixel data DATA, if through after the gamma correction, it is V that the gamma electric voltage OUT maximum of output is merely able to
BM, then gamma electric voltage OUT can not make the liquid crystal molecule of pixel have maximum light transmission.So, so that the brightness of pixel performs poor, and then influence the image display quality of display screen.Please refer to Fig. 8, it illustrates and shows that to being used to red pixel data carries out the synoptic diagram of the light transmission of gamma correction gained gamma electric voltage and liquid crystal molecule.The color that the present invention is used to show according to pixel data DATA is set the scope of different gamma electric voltage OUT.To be used to showing that red pixel data DATA is an example, the scope of its gamma electric voltage OUT can be by 0 to V
BM, in like manner, showing green pixel data DATA, the scope of its gamma electric voltage OUT can be by 0 to V
GMSo, just best brightness performance can both be arranged so that show red and green pixel.
In known method of operating, eight digital pixel data DATA, its data area is 0～255, the maximum magnitude of its pairing gamma electric voltage OUT only can arrive V
BMIn order to reach mentioned above, the purpose that makes the pixel that shows different colours can both have best brightness to show, so in the present invention, before carrying out gamma correction, carry out pixel data switch process 704 earlier, eight pixel data DATA are converted to nine conversion pixel data TDATA.Conversion pixel data TDATA denotable data area is greater than eight pixel data DATA.In other words, when carrying out gamma correction, the magnitude range of conversion pixel data TDATA pairing gamma electric voltage OUT greater than conventional pixel data DATA institute can correspondence the scope of gamma electric voltage OUT.So, TDATA carries out the resulting gamma electric voltage OUT of gamma correction with the conversion pixel data, and its voltage swing scope just is enough to contain the scope of red, blue, green three kinds of pairing gamma electric voltage OUT of color.
So the present invention is with V
RMBe the maximal value of gamma electric voltage OUT, and its pairing conversion pixel data TDATA is the maximal value of conversion pixel data TDATA.Because the gamma curve difference of different colours is also little, and the curve ranges of the overwhelming majority all overlaps each other.Please refer to Fig. 8, V
RMThe maximal value V of the gamma electric voltage OUT that sets with the well-known operations method
BMBoth sizes differ and not quite, so the maximal value gap of the maximal value of conversion pixel data TDATA and pixel data DATA is also little.In addition, the ratio of conversion pixel data TDATA is also passed through suitable setting, makes to be used to show that the pixel data DATA of different colours all can correspond to the conversion pixel data TDATA of same set of ratio.So have the situation generation that the pixel data DATA that shows different colours corresponds to identical conversion pixel data TDATA respectively.So, can save data area and the ratio of the required conversion pixel data TDATA that uses.In the present invention, only needing data area is 0～300 conversion pixel data TDATA, can carry out pixel data switch process 704.
Please refer to Fig. 9 A～9B, it illustrates and illustrates pixel data and the corresponding relation figure that changes pixel data.Below to convert three conversion pixel data TDATA ' to two pixel data DATA ' be example, pixel data switch process 704 of the present invention is described.Its data area of pixel data DATA ' of two is 0～3, represents with DATA ' (0,1,2,3) in Fig. 9 A.Owing to when carrying out gamma correction, need to expand the scope of pixel data DATA ', so must carry out the pixel data switch process, the color that is used to show according to pixel data DATA ' determines the conversion pixel data TDATA ' of its correspondence respectively.Being used to show that red pixel data DATA ' is an example, pixel data DATA ' 0,1,2, and 3 (with DATA ' (0,1,2,3) expressions), its pairing conversion pixel data is respectively 0,1,3 and 5 (with TDATA ' _ R (0,1,3,5) expressions).In like manner, be used to show the value of the conversion pixel data TDATA ' of green and blue pixels data DATA ' difference correspondence respectively with TDATA ' _ G (0,1,2,4) and TDATA ' _ B (0,1,2,3) expression, shown in Fig. 9 A.Pixel data DATA ' is represented with two binary mode, and the conversion pixel data TDATA ' that different colours is corresponding respectively represents with three binary mode, obtain the corresponding relation shown in Fig. 9 B.By Fig. 9 A and Fig. 9 B as can be known, the scope of pixel data DATA ' (0～3) is more or less the same with the scope (0～5) of conversion pixel data TDATA '.And because the difference of gamma curve is little, the pixel data DATA ' that shows different colours is to correspond to same conversion pixel data TDATA ' respectively.For example: be used to show blue with green pixel data DATA ' (10)
2Correspond to same conversion pixel data TDADA ' (010) respectively
3Wherein, (10)
2With (010)
3Representative is represented data respectively with the form of scale-of-two and three carries numerical value.Also have, be used to show blue pixels data DATA ' (11)
2And be used to show red pixel data DATA (10) though 2 both values are different, all correspond to identical conversion pixel data TDATA ' (011) respectively
3, shown in Fig. 9 B.By mentioned earlier through the example simplified as can be known, though three conversion pixel data TDATA ' can represent eight kinds of different data values altogether.But in fact only need 0～5, totally six kinds of different data values.In like manner, its data area of conversion pixel data TDATA of nine is 0～511, can represent 512 kinds of different data values altogether.But in fact the scope of data value does not need so greatly, only needs a part can set up the corresponding relation of pixel data DATA and conversion pixel data TDATA.Referring again to Fig. 8, in the present embodiment, conversion pixel data TDATA only needs 0～300 data area, promptly enough carries out pixel data switch process 704.
Be noted that because at the distribution comparatively dense of the pixel data DATA of gamma curve stage casing part, so with the also relative comparatively dense of distribution of the corresponding conversion pixel data of pixel data DATA TDATA.In other words, the interval between the two adjacent conversion pixel data TDATA is less.And in gamma curve leading portion and back segment part, the distribution of pixel data DATA is more sparse.So it is also relative more sparse with the distribution of the corresponding conversion pixel data of pixel data DATA TDATA.In other words, the interval between the two adjacent conversion pixel data TDATA is bigger.Pixel data DATA need make that through gained gamma electric voltage OUT corresponding with it after the gamma correction light transmission of pixel data DATA and pairing liquid crystal molecule is linear.
Referring again to Fig. 8, represent to be respectively 0,63,127,191 and 255 with decade, be used to show that red pixel data DATA is an example, its data value becomes an arithmetic progression in regular turn.When carrying out pixel data switch process 704, its corresponding respectively conversion pixel data TDATA be respectively 0,80,155,230 and 300.Conversion pixel data TDATA through after after correspondence is distinguished by institute after the gamma correction step 706 gamma electric voltage OUT imports liquid crystal panel, so that the light transmission of pixel data DATA and pairing liquid crystal molecule is linear.
When carrying out pixel data switch process 704, pixel data converting unit 604 is exported corresponding conversion pixel data TDATA according to the size of each pixel data DATA.Please refer to Figure 10, it illustrates the circuit block diagram of pixel data converting unit 604.Pixel data converting unit 604 also comprises pixel data conversion corresponding unit 1004 and pixel data conversion memory unit 1002.Pixel data conversion memory unit 1002 can (Synchronous DynamicRandom Access Memory SDRAM), be used to store pixel data DATA and the corresponding relation of changing pixel data TDATA in order together to go on foot dynamic RAM.Be noted that the corresponding relation of pixel data DATA and conversion pixel data TDATA is used to make the shown color of pixel along with pixel data DATA and different.In the present embodiment, though conversion pixel data DATA is nine a numerical data, only needing data area is 0～300 conversion pixel data TDATA, promptly enough carries out pixel data switch process 704.So, can save the capacity of the storer of pixel data conversion memory unit 1002.And pixel data conversion corresponding unit 1004 couples with pixel data conversion memory unit 1002, be used for the corresponding relation with conversion pixel data TDATA, output and the corresponding conversion pixel data of pixel data DATA TDATA according to the pixel data DATA that is stored in pixel data conversion memory unit 1002.
After the execution of step 704, follow execution in step 706, the gamma correction step.Pixel data converting unit 804 will be changed pixel data TDATA and input to gammate 606.Please refer to Figure 11, it illustrates the circuit block diagram of gammate 606.Gammate 606 also comprises gamma correction corresponding unit 1104 and gamma correction storage unit 1102.Gamma correction storage unit 1102 can be used to store the corresponding relation of conversion pixel data TDATA and gamma electric voltage OUT for together going on foot dynamic RAM (SDRAM).The corresponding relation that gamma correction method of the present invention will be changed pixel data TDATA and gamma electric voltage OUT is stored in the gamma correction storage unit 1102 in advance with the form of changing corresponding tables (look up table).Be noted that, be used to show that redness, blueness and green pixel data DATA are executing the pixel data switch process 704 conversion pixel data TDATA of gained afterwards respectively, its data area is also inequality, and is different so the corresponding relation of conversion pixel data TDATA and gamma electric voltage OUT is used to make the shown color of pixel along with pixel data DATA.Gamma correction corresponding unit 1104 couples with gamma correction storage unit 1102, is a digital analog converter (DAC).Be used for according to being stored in the conversion pixel data TDATA of gamma correction storage unit 1102 and the corresponding relation of gamma electric voltage OUT, output and the corresponding gamma electric voltage OUT of conversion pixel data TDATA.
At last, execution in step 708, gamma correcting device 602 output gamma electric voltage OUT finish the gamma correction operation.
The invention effect
The disclosed a kind of gamma correcting device that is used for LCD of the above embodiment of the present invention is stored in the corresponding relation of pixel data and the gamma electric voltage form with the conversion corresponding tables in the gamma correcting device in advance.And be used to show the pixel data of different colours, its corresponding gamma electric voltage of institute and inequality.So, can solve tradition to the pixel data that shows different colours to carry out the shortcoming of the method for operating of gamma correction with a kind of corresponding relation.Make the pixel data that is used to show different colours after carrying out gamma correction, the light transmission of pixel data and liquid crystal molecule is linear.
In addition, gamma correction method proposed by the invention is so that the magnitude range of the corresponding relation of pixel data and gamma electric voltage and gamma electric voltage is used for the color of demonstration along with pixel data and is different.When pixel shows different colors, liquid crystal molecule can both make pixel reach maximum light transmission under the control of gamma electric voltage, increasing the limited hardware condition and do not reducing under the situation that shows colourity, simultaneously red (R), green (G), blue (B) are shown optimization, to improve the image display quality of LCD.In sum; though the present invention with a preferred embodiment openly as above; so it is not to be used to limit the present invention; any those skilled in the art; under the situation that does not break away from the spirit and scope of the present invention; can carry out various changes and modification, so protection scope of the present invention should be with being as the criterion that accompanying Claim was limited.
Claims (16)
1. gamma correcting device that is used for LCD, this gamma correcting device is used for a pixel data is converted to a corresponding gamma electric voltage, exports in the pixel again, wherein, this pixel data is the binary data of M position, and M is a positive integer, and this gamma correcting device comprises at least:
One pixel data converting unit, be used for exporting a corresponding conversion pixel data according to this pixel data, wherein, this conversion pixel data is the binary data of N position, N is the positive integer greater than M, and the corresponding relation of this pixel data and this conversion pixel data is different with the shown color of this pixel; And
One gammate couples with this pixel data converting unit, is used for according to corresponding this gamma electric voltage of this conversion pixel data output, and wherein, the corresponding relation of this conversion pixel data and this gamma electric voltage is different with the shown color of this pixel.
2. gamma correcting device as claimed in claim 1, wherein the shown color of this pixel is red, blue and green wherein one.
3. gamma correcting device as claimed in claim 1, wherein work as this pixel and show redness respectively, when blue and green, import one first gamma electric voltage respectively, one second gamma electric voltage and one the 3rd gamma electric voltage, so that this pixel has high-high brightness, when this pixel shows redness, the maximal value of then exporting this gamma electric voltage of this gamma correcting device is this first gamma electric voltage, when this pixel shows blueness, the maximal value of exporting this gamma electric voltage of this gamma correcting device is this second gamma electric voltage, when this pixel showed green, the maximal value of exporting this gamma electric voltage of this gamma correcting device was the 3rd gamma electric voltage.
4. gamma correcting device as claimed in claim 1, wherein this pixel data converting unit also comprises:
One pixel data conversion memory unit is used to store the corresponding relation of this pixel data and this conversion pixel data; And
One pixel data conversion corresponding unit, couple with this pixel data conversion memory unit, be used for this pixel data being converted to corresponding this conversion pixel data according to being stored in this pixel data of this pixel data conversion memory unit and the corresponding relation of this conversion pixel data.
5. gamma correcting device as claimed in claim 4, wherein this pixel data conversion memory unit is a synchronous dynamic RAM.
6. gamma correcting device as claimed in claim 4, wherein those stored conversion pixel datas of this pixel data conversion memory unit are less than 2
8Individual.
7. gamma correcting device as claimed in claim 1, wherein this gammate also comprises:
One gamma correction storage unit is used to store the corresponding relation of this conversion pixel data and this gamma electric voltage; And
One gamma correction corresponding unit couples with this gamma correction storage unit, is used for should changing pixel data and being converted to corresponding this gamma electric voltage according to being stored in this conversion pixel data of this gamma correction storage unit and the corresponding relation of this gamma electric voltage.
8. gamma correcting device as claimed in claim 7, wherein this gamma correction storage unit is a synchronous dynamic RAM.
9. as the described gamma correcting device of claim body, wherein this gamma correcting device is arranged in the driving circuit of this LCD.
10. gamma correcting device that is used for LCD, this gamma correcting device is used for a pixel data is converted to a corresponding gamma electric voltage, input to a pixel again, this pixel is used to show redness, blueness and green wherein one, when this pixel shows redness, blueness respectively and when green, import one first gamma electric voltage, one second gamma electric voltage and one the 3rd gamma electric voltage respectively, so that this pixel has high-high brightness, this gamma correcting device comprises at least:
One pixel data converting unit is used for exporting a corresponding conversion pixel data according to this pixel data, and this pixel data converting unit comprises at least:
One pixel data conversion memory unit is used to store the corresponding relation of this pixel data and this conversion pixel data; And
One pixel data conversion corresponding unit, couple with this pixel data conversion memory unit, be used for this pixel data being converted to this conversion pixel data according to being stored in this pixel data of this pixel data conversion memory unit and the corresponding relation of this conversion pixel data; Wherein, this conversion pixel data is the binary data of N position, and the binary data that this conversion pixel data is the N position, and M, N are all positive integer, and M is less than N, and the color that shows along with pixel of the corresponding relation of this pixel data and this conversion pixel data and different; And
One gammate couples with this pixel data converting unit, and this gammate also comprises:
One gamma correction storage unit is used to store the corresponding relation of this conversion pixel data and this gamma electric voltage; And
One gamma correction corresponding unit, couple with this gamma correction storage unit, be used for according to being stored in this conversion pixel data of this gamma correction storage unit and the corresponding relation of this gamma electric voltage, should change pixel data and be converted to corresponding this gamma electric voltage, wherein, the corresponding relation of this conversion pixel data and this gamma electric voltage, different along with the shown color of pixel;
Wherein, when this pixel shows redness, the maximal value of then exporting this gamma electric voltage of this gamma correcting device is this first gamma electric voltage, when this pixel shows blueness, the maximal value of exporting this gamma electric voltage of this gamma correcting device shows that for this second gamma electric voltage, when this pixel when green, the maximal value of exporting this gamma electric voltage of this gamma correcting device is the 3rd gamma electric voltage.
11. a gamma correction method that is used for LCD is used for a pixel data is converted to a gamma electric voltage, wherein, this pixel data is the binary data of M position, M is a positive integer, and this gamma electric voltage is used to input to a pixel, and this pixel data conversion method comprises the following steps: at least
This pixel data is converted to a corresponding conversion pixel data, and wherein, this conversion pixel data is the binary data of N position, and N is the positive integer greater than M, and the corresponding relation of this pixel data and this conversion pixel data is different with the shown color of this pixel; And
Should change pixel data and be converted to corresponding this gamma electric voltage, wherein, the corresponding relation of this conversion pixel data and this gamma electric voltage is different with the shown color of this pixel.
12. gamma correction method as claimed in claim 11, wherein the shown color of this pixel is red, blue and green wherein one.
13. gamma correction method as claimed in claim 12, wherein, when this pixel shows redness, blueness respectively and when green, import one first gamma electric voltage, one second gamma electric voltage and one the 3rd gamma electric voltage respectively, so that this pixel has high-high brightness, when this pixel shows redness, then the maximal value of this gamma electric voltage is this first gamma electric voltage, when this pixel shows blueness, then the maximal value of this gamma electric voltage is this second gamma electric voltage, when this pixel showed green, then the maximal value of this gamma electric voltage was the 3rd gamma electric voltage.
14. gamma correction method as claimed in claim 11, wherein this gamma correction method is implemented by a gamma correcting device.
15. gamma correction method as claimed in claim 14, this gamma correcting device is arranged in the driving circuit of this LCD.
16. gamma correction method that is used for LCD, be used for a pixel data is converted to a corresponding gamma electric voltage, input to a pixel again, this pixel is used to show redness, blueness and green wherein one, when this pixel shows redness, blueness respectively and when green, import one first gamma electric voltage, one second gamma electric voltage and one the 3rd gamma electric voltage respectively, so that this pixel has high-high brightness, this pixel data conversion method comprises the following steps: at least
This pixel data is converted to a corresponding conversion pixel data, wherein, this pixel data is the binary data of M position, and the binary data that this conversion pixel data is the N position, M, N are all positive integer, and M is less than N, and the corresponding relation of this pixel data and this conversion pixel data is different with the color of this pixel demonstration; And
Should change pixel data and be converted to corresponding this gamma electric voltage, wherein, the corresponding relation of this conversion pixel data and this gamma electric voltage is different with the color of pixel demonstration;
Wherein, when this pixel showed redness, then the maximal value of this gamma electric voltage was this first gamma electric voltage, when this pixel shows blueness, then the maximal value of this gamma electric voltage is this second gamma electric voltage, shows that when green, then the maximal value of this gamma electric voltage is the 3rd gamma electric voltage when this pixel.
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