Present patent application be that on 07 23rd, 2002, application number are 02826265.4 the applying date, exercise question divides an application for the patented claim of " LCD and drive unit thereof ".
Embodiment
Accompanying drawing below with reference to the preferred embodiment of the present invention shown in it is more fully described the present invention.But the present invention can be implemented as a lot of different forms, and should not be interpreted as being subject to the embodiment that proposes here.Identical Reference numeral is quoted components identical all the time.
Now, be described in detail with reference to the attached drawings LCD and drive unit thereof according to various embodiments of the present invention.
With reference to figure 1 and Fig. 2, with data driver and the gamma reference voltage generator of describing in detail according to the embodiment of the invention.
Fig. 1 is the synoptic diagram according to the exemplary data driver of the embodiment of the invention, and the configuration of the exemplary gamma reference voltage generator shown in Fig. 2 key diagram 1.
As shown in Figure 1, the data driver 10 according to the embodiment of the invention comprises gamma register 100, gamma reference voltage generator 200, shift register 300, data register 400, data latches 500, D/A converter 600 and output buffer 700.R, the G of shift register 300 controller of self-timing in the future (not shown) and B data (D0[7:0]-D5[7:0]) be shifted, and in data register 400, store these data.D/A converter 600 receives the data that are stored in the data register 400 from data latches 500, and these data are converted to analog gray voltages.The analog gray voltages that output buffer 700 is stored from D/A converter 600, and when receiving load signal, this analog gray voltages is applied on a plurality of data lines.The digital gamma data of gamma register 100 storage each R, G and B color, and gamma reference voltage generator 200 produces a plurality of sets of gamma reference voltages of each R, G and B color according to being stored in value in the gamma register 100, to offer D/A converter 600.
As shown in Figure 2, gamma register 100 receives digital gamma data by a plurality of data buss from the timing controller (not shown), and response gamma load signal GMA_load stores this digital gamma data.Gamma reference voltage generator 200 is connected to two external voltage source AVDD and GND, and the digital gamma data of shades of colour and various polarity is converted to the analogue value, with as just/negative reference voltage offers D/A converter 600.
Describe the gamma reference voltage generator of a plurality of embodiment according to the present invention now in detail.In these embodiment of the present invention, the number that is assumed to be the digital gamma data group that gamma reference voltage generator 200 provides equals 9 * 2 * 3, promptly positive R, G and B digital gamma data D
V1R-D
V9R, D
V1G-D
V9GAnd D
V1B-D
V9B, and negative R, G and B digital gamma data D
V10R-D
V18R, DV
10G-D
V18GAnd D
V10B-D
V18BBut, the invention is not restricted to this, but be applicable to the digital gamma data group of any number.
At first, with reference to the gamma reference voltage generator of figure 3 explanations according to first embodiment of the invention.
Fig. 3 is the figure of explanation according to the exemplary gamma reference voltage generator of first embodiment of the invention.
As shown in Figure 3, the gamma reference voltage generator 200 according to first embodiment of the invention comprises positive gamma reference voltage generator 210 and the negative gamma reference voltage generator 240 that produces the positive and negative gamma electric voltage respectively.
In this embodiment, gamma reference voltage generator 200 receives the digital gamma data of each R, G and B color simultaneously from gamma register 100, and each D/A converter (" DAC ") 221-223 and 251-253 produce corresponding gamma reference voltage.In order to make gamma reference voltage generator 200 produce all R, G and B gamma reference voltage, DAC221-223 that provides in gamma reference voltage generator 200 and the number of 251-253 are corresponding to the number of R, G and B digital gamma data.For example, the gamma reference voltage generator 200 according to first embodiment of the invention preferably includes 9 * 2 * 3 DAC.
In detail, positive gamma reference voltage generator 210 is for each R, G and B color comprise 9 DAC 221-223, and positive R, the G of analog-converted correspondence and B digital gamma data DV1R-DV9R, DV1G-DV9G and DV1B-DV9B are to produce positive R, G and B gamma reference voltage V1R-V9R, V1G-V9G and V1B-V9B separately.Equally, negative gamma reference voltage generator 240 is for each R, G and B color comprise 9 DAC 251-253, separately with positive R, the G of correspondence and B digital gamma data DV10R-DV18R, DV10G-DV18G and DV10B-DV18B analog-converted for bearing R, G and B gamma reference voltage V10R-V18R, V10G-V18G and V10B-V18B.
D/A converter 600 is converted to aanalogvoltage according to the positive and negative gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, V10R-V18R, V10G-V18G and the V10B-V18B that provide from DAC 221-223 and 251-253 with R, G and B view data R0, G0, B0, R1, G1, B1....
Simultaneously, the number of DAC can reduce with respect to first embodiment of the invention in the gamma reference voltage generator 200, below, will such embodiment be described with reference to figure 4 to 12.
At first, with reference to the gamma reference voltage generator of Figure 4 and 5 description according to second embodiment of the invention.
Fig. 4 is the figure of explanation according to the exemplary gamma reference voltage generator of second embodiment of the invention, and Fig. 5 illustrates the circuit diagram that is included in according to the example sampled/holding circuit in the gamma reference voltage generator of second embodiment of the invention.
As shown in Figure 4, gamma reference voltage generator 200 according to second embodiment of the invention also comprises positive and negative gamma reference voltage generator 210 and 240, and the gamma reference voltage generator 210 and 240 of positive and negative includes DAC unit 220 and 250 and sampling/ holding unit 230 and 260.
DAC unit 220 comprises 9 DAC, be used for analog-converted according to positive digital gamma data DV1R-DV9R, the DV1G-DV9G of the input of the timesharing of each R, G and B color mechanism and DV1B-DV9B to produce positive R, G and B gamma reference voltage V1R-V9R, V1G-V9G and V1B-V9B.Sampling/holding unit 230 comprises a plurality of sample/hold circuits unit (S/HI) 231-233, and positive R, G and B gamma reference voltage V1R-V9R, V1G-V9G and V1B-V9B from DAC unit 220 are used to sample.Equally, DAC unit 250 comprises 9 DAC, is used for analog-converted and bears R, G and B gamma reference voltage V10R-V18R, V10G-V18G and V10B-V18B according to machine-processed negative word gamma data DV10R-DV18R, DV10G-DV18G that imports of the timesharing of each R, G and B color and DV10B-DV18B to produce.Sampling/holding unit 260 comprises a plurality of sample/hold circuits unit (S/HI) 261-263, and negative gamma reference voltage V10R-V18R, V10G-V18G and V10B-V18B from DAC unit 250 are used to sample.
In detail, 231 samplings positive R gamma reference voltage V1R-V9R in R sample/hold circuit unit is to offer D/A converter 600.D/A converter 600 will be converted to aanalogvoltage from R view data R0, the R1... of data latches 500 according to the positive R gamma reference voltage V1R-V9R of sampling.According to identical mode, G and B sample/ hold circuit unit 262 and 263 sample respectively positive G gamma reference voltage V1G-V9G and positive B gamma reference voltage V1B-V9B are to offer D/A converter 600.DAC unit 250 in the negative gamma reference voltage generator 240 and sampling/holding unit 260 analog-converted negative R, G and B digital gamma data, bear R, G and B gamma reference voltage V10R-V18R, V10G-V18G and V10B-V18B to produce, and sample to offer D/A converter 600.
Describe the sample/hold circuit unit 231-233 of sampling/ holding unit 230 and 260 and a unit 231 among the 261-263 in detail below with reference to Fig. 5.
Sampling/holding unit 231 comprises 9 sample/hold circuits, is respectively applied for the positive R gamma reference voltage from 9 DAC of DAC unit 220 is sampled.Each sample/hold circuit comprises switch SW, capacitor C1 and impact damper buf.When switch SW response sample commencing signal and when closed, be stored among the capacitor C1 and be sampled from the gamma reference voltage of DAC, and the gamma reference voltage of being sampled offer D/A converter 600 by analogue buffer.
The DAC number that provides in the gamma reference voltage generator 200 according to second embodiment of the invention equals 9+9=18, is reduced to according to 1/3 of the number of the invention described above first embodiment.
Although second embodiment of the invention adopts independent DAC unit respectively for positive polarity and negative polarity, also can use the DAC that can support positive polarity can support negative polarity again.Below, with reference to figure 6 such embodiment is described.
Fig. 6 is the figure according to the exemplary gamma reference voltage generator of third embodiment of the invention.
As shown in Figure 6, except using for the positive and negative digital gamma data the single DAC unit 220, almost identical with second embodiment according to the gamma reference voltage generator 200 of third embodiment of the invention.
In detail, DAC unit 220 comprises 9 DAC, and analog-converted is according to positive R, G and B digital gamma data DV1R-DV9R, DV1G-DV9G and the DV1B-DV9B of the timesharing mechanism order input of each R, G and B color and polarity, and negative R, G and B digital gamma data DV10R-DV18R, DV10G-DV18G and DV10B-DV18B, to produce positive and negative R, G, B gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, V10R-V18R, V10G-V18G and V10B-V18B.In addition, DAC unit 220 provides positive and negative R, G, B gamma reference voltage to two sampling/ holding units 230 and 260 respectively.Sampling/holding unit 230 with 260 basically with second embodiment of the invention in describe identical.
The DAC number that is provided in the gamma reference voltage generator 200 according to third embodiment of the invention is 9, is reduced to according to 1/6 of the number of first embodiment of the invention.
According to the of the present invention second and the 3rd embodiment, because the timing controller (not shown) is imported R, G and B digital gamma data according to the timesharing mechanism order of each R, G and B color, therefore number and this digital gamma data of the DAC that provides in the DAC unit are to concern one to one.But 18 digital gamma data of each R, G and B color can be imported in proper order.Describe such embodiment in detail below with reference to accompanying drawing.
At first, with reference to figure 7 and the 8 gamma reference voltage generators of describing according to fourth embodiment of the invention.
Fig. 7 is the figure according to the exemplary gamma reference voltage generator of fourth embodiment of the invention, and the example sampled/holding circuit unit that is provided in the gamma reference voltage generator of Fig. 8 explanation according to fourth embodiment of the invention.
As shown in Figure 7, gamma reference voltage generator 200 also comprises the positive and negative gamma reference voltage generator 210 and 240 as first embodiment.Positive gamma reference voltage generator 210 comprises 3 DAC221-223 that correspond respectively to positive R, G and B digital gamma data DV1R-DV9R, DV1G-DV9G and DV1B-DV9B, and 3 sampling/holding unit 231-233 that are connected to corresponding DAC221-223.According to identical mode, negative gamma reference voltage generator 240 comprises 3 DAC251-253 and 3 sampling/holding unit 261-263 that correspond respectively to R, G and B digital gamma data DV10R-DV18R, DV10G-DV18G and DV10B-DV18B.
As shown in Figure 7, be input to DAC221-223 and 251-253 from positive and negative R, the G of timing controller and B digital gamma data DV1R-DV9R, DV1G-DV9G, DV1B-DV9B, DV10R-DV18R, DV10G-DV18G and DV10B-DV18B according to corresponding R, G and B color and corresponding polarity serial.DAC221-223 and these digital gamma data of 251-253 analog-converted, and to positive and negative gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, V10R-V18R, V10G-V18G and the V10B-V18B of corresponding sample/hold circuit unit 231-233 and 261-263 serial output through analog-converted.Sample/hold circuit unit 231-233 and 261-263 sample to positive and negative gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, V10R-V18R, V10G-V18G and V10B-V18B respectively, to offer D/A converter 600.
Each sample/hold circuit unit 231-233 of the second and the 3rd embodiment and 261-263 sample simultaneously and export 9 gamma reference voltages according to the present invention although Fig. 5 is described, sequentially sample and export the gamma reference voltage of serial input according to the sample/hold circuit unit 231-233 of fourth embodiment of the invention and 261-263.For example, as shown in Figure 8, a sample/hold circuit unit 231 comprises 9 sample/hold circuits that are connected to DAC 221 output terminals.This sample/hold circuit comprises: switch SW is used for the gamma reference voltage of switch from DAC 221; Capacitor C1 is used to store the gamma reference voltage by the switch SW input; Analogue buffer buf is used for exporting the gamma reference voltage that is stored in capacitor C1 to D/A converter 600; And shift register S/R, be used for transmitting the sampling commencing signal that is used for the gauge tap closed and disconnected to next sample/hold circuit.
231 responses of sample/hold circuit unit are by the displacement of the sampling commencing signal of shift register S/R, and order output is from the gamma reference voltage of DAC 221.
According to fourth embodiment of the invention, because gamma reference voltage generator 200 adopts 6 DAC to be respectively applied for positive and negative R, G and B color, so the decreased number of DAC is according to 1/3 of the number of second embodiment.
Although each R, G and DAC of B color assignment for having each polarity in the fourth embodiment of the present invention, DAC can be uncorrelated with polarity.Below with reference to Fig. 9 such embodiment is described.
Fig. 9 is the figure of explanation according to the exemplary gamma reference voltage generator of fifth embodiment of the invention.
As shown in Figure 9, comprise R, G and B gamma reference voltage generator 210r, 210g and 210b, be used to produce corresponding R, G and B gamma reference voltage according to the gamma reference voltage generator 200 of fifth embodiment of the invention.Each R, G and B gamma reference voltage generator 210r, 210g and 210b comprise DAC 220r, 220g and 220b and sampling/ holding unit 230r, 230g and 230b respectively, and each sampling/ holding unit 230r, 230g and 230b comprise two sample/hold circuit unit (S/HII ') 231r and 232r, 231g and 232g and 231b and 232b.DAC 220r, 220g and 220b analog-converted be from R, G and B digital gamma data DV1R-DV18R, DV1G-DV18G and the DV1B-DV18B of timing controller serial received, and respectively to sampling/ holding unit 230r, 230g and 230b output R, G and B gamma reference voltage V1R-V18R, V1G-V18G and the V1B-V18B through analog-converted.In sampling/ holding unit 230r, 230g and 230b, except the sampling commencing signal of output as sample/ hold circuit unit 232r, 232g and 232b of last shift register S/R of sample/ hold circuit unit 231r, 231g and 231b, that describes among sample/ hold circuit unit 231r and 232r, 231g and 232g and 231b and 232b and Fig. 8 is identical.
In detail, sample/hold circuit unit 231r carries out sequential sampling according to the sampling commencing signal to the positive R gamma reference voltage V1R-V9R from the R gamma reference voltage V1R-V18R of DAC 220r serial output, and export them to D/A converter 600, and sample/hold circuit unit 232r carries out sequential sampling according to the output of last shift register S/R of sample/hold circuit unit 231r to negative R gamma reference voltage V10R-V18R, and exports them to D/A converter 600.According to identical mode, sample/ hold circuit unit 231g and 231b align G and B gamma reference voltage V1G-V9G and V1B-V9B respectively and carry out sequential sampling according to the sampling commencing signal, and sample/ hold circuit unit 232g and 232b carry out sequential sampling to negative G and B gamma reference voltage V10G-V18G and V10B-V18B respectively according to the output of last shift register S/R of sample/ hold circuit unit 231g and 231b.
According to a fifth embodiment of the invention, the decreased number of DAC is half of the 4th embodiment.Although the 5th embodiment has DAC among R, G and the B each, DAC can also be used for every kind of polarity.Below with reference to Figure 10 such embodiment is described.
Figure 10 explanation is according to the exemplary gamma reference voltage generator of sixth embodiment of the invention.
As shown in figure 10, comprise positive and negative gamma reference voltage generator 210 and 240 according to the gamma reference voltage generator of sixth embodiment of the invention as first embodiment of the invention.Positive gamma reference voltage generator 210 comprises a DAC 220 and has sampling/holding unit 230 of 3 sample/hold circuit unit 231-233.Negative gamma reference voltage generator 240 comprises a DAC 250 and has sampling/holding unit 260 of 3 sample/hold circuit unit 262-263.
The positive R of DAC 220 serial received, G and B digital gamma data DV1 R-DV9R, DV1G-DV9G, DV1B-DV9B converting them to gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, and output to sampling/holding unit 230 with it.According to same way as, DAC 250 serial received negative R, G and B digital gamma data DV10R-DV18R, DV10G-DV18G and DV10B-DV18B, converting them to gamma reference voltage V10R-V18R, V10G-V18G and V10B-V18B, and it is outputed to sampling/holding unit 260.
The sample/hold circuit unit 231-233 of sampling/holding unit 230 aligns R, G respectively and B gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B sample, as described in the 5th embodiment, except the output of last shift register S/R of sample/ hold circuit unit 231 and 232 becomes respectively the sampling commencing signal of sample/ hold circuit unit 232 and 233, these sample/hold circuit unit are identical with the described sample/hold circuit of Fig. 8 unit.According to identical mode, the sample/hold circuit unit 261-263 of sampling/holding unit 260 samples to bearing R, G and B gamma reference voltage V10R-V18R, V10G-V18G and V10B-V18B respectively.
Gamma reference voltage generator according to sixth embodiment of the invention has only used two DAC.
Simultaneously, produce among R, G and the B gamma reference voltage of each for the polarity of not considering gamma reference voltage, can only use a DAC.Below with reference to Figure 11 such embodiment is described.
Figure 11 is the figure of explanation according to the exemplary gamma reference voltage generator of seventh embodiment of the invention.
As shown in figure 11, comprise a DAC 220 and sampling/holding unit 230 according to the gamma reference voltage generator 200 of seventh embodiment of the invention, and sample/holding unit 230 comprises 6 sample/hold circuit unit 231-233 and 261-263.Provide positive and negative R, G, B digital gamma data DV1R-DV9R, DV1G-DV9G, DV1B-DV9B, DV10R-DV18R, DV10G-DV18G and DV10B-DV18B to DAC 220 serials, converting them to positive and negative R, G, B gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, V10R-V18R, V10G-V18G and V10B-V18B, and export them to sampling/holding unit 230.With describe among the 6th embodiment identical, the sample/hold circuit unit 231-233 of sampling/holding unit 230 aligns R, G and B gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B sample, and the output of last shift register of sample/hold circuit unit 233 becomes the sampling commencing signal of sample/hold circuit unit 261.Then, sample/hold circuit unit 261-263 samples to negative R, G and B gamma reference voltage V10R-V18R, V10G-V18G, V10B-V18B according to this sampling commencing signal.
Above-mentioned the 7th embodiment according to the present invention has only a DAC to be used to produce gamma reference voltage.
Simultaneously, the time that the generation gamma reference voltage of the second and the 3rd embodiment is spent is respectively 3 times and 6 times of first embodiment, and the time that the generation gamma reference voltage of the 4th and the 5th embodiment is spent is respectively 9 times and 18 times of first embodiment.The time that the generation gamma reference voltage of the 7th embodiment is spent is 54 times of first embodiment.
Suppose that it is 1 μ s that a DAC produces the time that gamma reference voltage spent, then the DAC of Fig. 5 spends 1 μ s, and the DAC of Figure 11 spends 54 μ s.Because this time is shorter than the blank time interval that interframe does not have data, so display screen can not go wrong.
But, cause in this time under the situation of problem, can adopt sample/hold circuit cell S/HIII to reduce the time.
Figure 12 illustrates example sampled/holding circuit S/H III according to another embodiment of the present invention.
As shown in figure 12, sample/hold circuit cell S/H comprises 9 sample/hold circuits that are connected to the DAC output terminal according to another embodiment of the present invention, and this sample/hold circuit comprises switch SW, shift register S/R, capacitor C1 and C2, analogue buffer buf and input and output switch S 1 and S2.According to sampling commencing signal operating switch SW, to send the gamma reference voltage from DAC, shift register S/R transmits the sampling commencing signal to next sample/hold circuit.Capacitor C1 and C2 are connected to first and second paths, thus the gamma reference voltage charging to transmit along first and second paths, and the gamma reference voltage that analogue buffer buf charges in capacitor C1 and C2 to D/A converter 600 outputs.In this case, input switch S1 is connected between the switch SW and first and second paths, thereby according to selecting signal between first and second paths, to replace, and output switch S 2 is connected between first and second paths and the analogue buffer, thereby according to selecting signal between first and second paths, to replace.
In this sample/hold circuit cell S/H III, according to transmit the sampling commencing signal by shift register S/R, order output is from the gamma reference voltage of a terminal input.
The operation of sample/hold circuit cell S/H III is described below.
When existing gamma electric voltage is stored among the capacitor C2, the gamma reference voltage that changes is stored among the capacitor C1, thereby with the gamma reference voltage that capacitance stores was changed corresponding to capacitor C1, after this, by changing the gamma reference voltage of selecting signal to come output capacitor C1.Then, change gamma reference voltage in a short period of time.When keeping this state and changing gamma reference voltage, new gamma reference voltage is stored among the capacitor C2, and after finishing the new gamma reference voltage of storage, only exports the gamma reference voltage that charges in capacitor C2.
In the foregoing description and following embodiment, can use this sample/hold circuit S/H III to substitute sample/hold circuit S/H II and S/H II '.
The embodiment that a lot is used at the inboard of data driver 10 generation gamma reference voltage and reduces to be used to produce the DAC area occupied of gamma reference voltage has been described in the above.
Simultaneously, the DAC that is used to produce gamma reference voltage can realize away from data driver 10, describes such embodiment below with reference to Figure 13 to Figure 18 is concise and to the point.
Figure 13 is the figure according to the exemplary gamma reference voltage generator of eighth embodiment of the invention.
With reference to Figure 13, except the outside at data driver 10 is provided for receiving respectively positive and negative digital gamma data DV1R-DV9R, DV1G-DV9G, DV1B-DV9B, DV10R-DV18R, DV10G-DV18G, DV10B-DV18B with the positive and negative gamma reference voltage generator 220 and 250 that produces positive and negative gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, V10R-V18R, V10G-V18G, V10B-V18B, the eighth embodiment of the present invention is identical with second embodiment.
Positive and negative gamma reference voltage generator 220 and 250 is made up of the digital analog converter of multichannel system respectively, and they are at the ground of each timesharing among R, G and B output positive and negative R, G and B gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, V10R-V18R, V10G-V18G, V10B-V18B.Sampling/ holding unit 230 and 260 are provided in data driver 10, and they receive positive and negative R, G, B gamma reference voltage and to its sampling from positive and negative gamma reference voltage generator 220 and 250 respectively.Sampling/holding unit 230 with 260 with first embodiment in identical.
Although the eighth embodiment of the present invention has two digital analog converters of the multichannel system of dividing for each polarity, also can have only a digital analog converter and do not consider polarity, as shown in figure 14.
Figure 14 explanation is according to the exemplary gamma reference voltage generator of ninth embodiment of the invention.
As shown in figure 14, except the outside at data driver 10 is provided for receiving digital gamma data DV1R-DV9R, DV1G-DV9G, DV1B-DV9B, DV10R-DV18R, DV10G-DV18G, DV10B-DV18B with the gamma reference voltage generator 220 that produces gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, V10R-V18R, V10G-V18G, V10B-V18B from timing controller, the 9th embodiment is identical with the 3rd embodiment.
Gamma reference voltage generator 220 is made up of digital analog converter, and at each timesharing ground among R, G and the B to sample/hold circuit unit 231-233 and 261-263 output positive and negative R, G, B gamma reference voltage V1R-V9R, V1G-V9G, V1B-V9B, V10R-V18R, V10G-V18G, V10B-V18B.In data driver 10, be provided for receiving respectively positive and negative R, G, B gamma reference voltage and to its sample/hold circuit unit 231-233 and 261-263 that samples.Sample/hold circuit unit 231-233 and 261-263 are identical with second embodiment's.
As shown in figure 15, except positive and negative gamma reference voltage generator 220 and 250 receives the positive and negative gamma reference voltage by timing controller and digital interface respectively, to produce outside the positive and negative gamma reference voltage, the tenth embodiment of the present invention is identical with the 4th embodiment.
Each positive and negative R, G, B gamma reference voltage among positive and negative gamma reference voltage generator 220 and 250 serialization R, G and the B, thus they are offered sampling/ holding unit 230 and 260 in the data driver 10.Sampling/ holding unit 230 and 260 identical with the 4th embodiment.
As shown in figure 16, except gamma reference voltage generator 220 receives digital gamma data to produce the gamma reference voltage by timing controller and digital interface, the 11st embodiment of the present invention is identical with the 5th embodiment.The gamma reference voltage of each among gamma reference voltage generator 220 serialization R, G and the B, thus they are offered sampling/ holding unit 230r, 230g and 230b in the data driver 10.These sampling/ holding units 230r, 230g are identical with 230b with sampling/ holding unit 230r, 230g of the 5th embodiment with 230b.
As shown in figure 17, except positive and negative gamma reference voltage generator 220 and 250 receives the positive and negative gamma reference voltage to produce the positive and negative gamma reference voltage by timing controller and digital interface respectively, the 12nd embodiment of the present invention is identical with the 6th embodiment.Each positive and negative R, G, B gamma reference voltage among positive and negative gamma reference voltage generator 220 and 250 serialization R, G, the B, thus they are offered sampling/ holding unit 230 and 260 in the data driver 10.Sampling/ holding unit 230 and 260 comprises 3 sample/hold circuit unit 231-233 and 261-263 as the 6th embodiment respectively.
As shown in figure 18, except gamma reference voltage generator 220 receives digital gamma data to produce the gamma reference voltage by timing controller and digital interface, the 13rd embodiment of the present invention is identical with the 7th embodiment.The gamma reference voltage of each among gamma reference voltage generator 220 serialization R, G and the B, thus they are offered sampling/holding unit 230 in the data driver 10.This sampling/holding unit 230 comprises 6 samplings as the 7th embodiment/holding unit 231-233 and 261-263.
As mentioned above, have among R, G and the B gamma reference voltage of each, therefore can adjust colour temperature and colour match as required owing to data driver can use the gamma reference voltage of each among R, G and the B.
In addition, can realize the tone that the characteristic by liquid crystal or color filter limits more changefully.
And, even in motion picture, also can obtain active screen, because receive digital gamma data and make new gamma data can put on each frame from timing controller.Certainly, when adopting aforesaid drive IC, timing controller preferably also can change.That is to say, when when timing controller is powered, this timing controller preferably transmits among R, G and the B each gamma value as numeric type to data driver, and it is preferably so that can transmit gamma value by the mode that the on-screen data of analyzing input when active screen is watched in expectation is adjusted gamma value.