CN1477614A - Liquid crystal display driving method, liquid crystal display and monitor with the same - Google Patents
Liquid crystal display driving method, liquid crystal display and monitor with the same Download PDFInfo
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- CN1477614A CN1477614A CNA021420084A CN02142008A CN1477614A CN 1477614 A CN1477614 A CN 1477614A CN A021420084 A CNA021420084 A CN A021420084A CN 02142008 A CN02142008 A CN 02142008A CN 1477614 A CN1477614 A CN 1477614A
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- 239000004973 liquid crystal related substance Substances 0.000 title claims abstract description 177
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- 230000007613 environmental effect Effects 0.000 description 4
- 238000010422 painting Methods 0.000 description 4
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- 230000015572 biosynthetic process Effects 0.000 description 3
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Abstract
The present invention provides a method for driving liquid crystal display. The method can prevent the gamkma characteristic linearity from reducing and can use simple and low-cost structure to implement high-quality image display. The method includes: obtaining first correction red data, first correction green data and first correction blue data, each has 10 bits, and when the gamma correction of the red data, green data and blue data with 8 bits is made, the information for changing every red data, green data and blue data grey level for twice or several times is added on it, and feeding the produced data red signal, data green signal and data blue signal into the data electrode of the liquid crystal display to implement frame frequency control.
Description
Background of invention
Invention field
The present invention relates to be used for driving method, the liquid crystal display device of the LCD that is used as personal computer, TV monitors such as (televisors) and the monitor that is provided with this liquid crystal display device, and more particularly, relate to by in a step-wise fashion light and shade drive LCD with display gray scale method being set for character, image etc., adopt said method to drive the liquid crystal display device of LCD, and the monitor that is provided with above-mentioned liquid crystal display device.
Description of Related Art
Figure 13 represents the block diagram of disclosed conventional liquid crystal part among the routine Japanese Patent Application Publication No.2001-134242.As shown in Figure 13, this conventional liquid crystal part 1 comprises a colour liquid crystal display device 1, control circuit 2, gray scale source circuit 3, data electrode driver circuit 4 and scan electrode driving circuit 5.
Colour liquid crystal display device 1 uses and for example adopts the active array type colour liquid crystal display device of thin film transistor (TFT) (TFT) as on-off element.In colour liquid crystal display device 1, be used as pixel with a plurality of scan electrodes (gate line) of specific interval setting with along column direction with a plurality of data electrodes (source electrode line) region surrounded that specific interval is provided with by following direction.In colour liquid crystal display device 1,, and be used for capacitor at a vertical sync period accumulation data electrode for each pixel is provided with liquid crystal cell, the public electrode that is equivalent to capacitive load, the TFT that is used to drive corresponding liquid crystal cell.For driving colour liquid crystal display device 1, as common electric voltage V
ComWhen being applied to public electrode, according to red data D
R, green data D
GWith blue data D
BThe blue signal of green signal of data red signal, data that is all digital of digital video data that produces and data is fed to data electrode, simultaneously according to horizontal-drive signal S
H, vertical synchronizing signal S
VBe fed to scan electrode Deng the sweep signal that produces.This makes color character or image be presented on the display screen of colour liquid crystal display device 1.Colour liquid crystal display device 1 is SXGA (Super Extended GraphicsArray, a super XGA (Extended Graphics Array)) type LCD, has the resolution of 1280 * 1024 pixels.
The following describes Gamma correction.The following expression of reproducing characteristic, initial gamma camera is absorbed for example logarithm value paintings horizontal ordinate of the brightness that has such as landscape, personage of the object that occurs in the photograph, the logarithm value paintings ordinate of the brightness of the shown picture reproducing of vision signal that will present from gamma camera, if the pitch angle of above-mentioned reproducing characteristic curve is " θ ", then the value defined with tan θ is gamma (γ).If object brightness is reproduced on the display truly, that is to say, if the logarithm value of paintings horizontal ordinate (input value) increases or reduces 1 and the logarithm value (output valve) of paintings ordinate increases or reduces 1, then the reproducing characteristic curve becomes the straight line with 45 ° of pitch angle, and because tan45 °=1, so gamma equals 1.Therefore, the gamma for the total system of the imaging device that reproduces the brightness of object truly, comprise the formation gamma camera that is used to obtain the object image and CRT (cathode-ray tube (CRT)) display that is used for picture reproducing is necessary for 1.Yet each imaging device that constitutes gamma camera for example CCD (charge-coupled image sensor) etc. and each CRT monitor etc. has himself specific gamma value.For example, the gamma value of CCD is 1, and the gamma value of CRT monitor is about 2.2.Therefore, for the gamma value that makes total system is 1 to obtain picture reproducing with good gray level, need proofread and correct picture intelligence, this correction is called " Gamma correction ".In the ordinary course of things, vision signal being carried out Gamma correction makes picture intelligence to match with the characteristic (gamma characteristic) of CRT monitor.
By Gamma correction part 7
1To 7
3The Gamma correction that carries out comprises first Gamma correction and the second gamma fine correction, the second gamma fine correction is used for the difference between redness, green and the blueness that can not be proofreaied and correct fully by the rough correction of another gamma is proofreaied and correct, wherein rough correction of another gamma undertaken by data electrode driver circuit 4, is used for redness, green and blueness are jointly carried out Gamma correction (back will be illustrated).Here, first Gamma correction is represented to offer the Gamma correction that the brightness of input imagery is carried out arbitrarily in order to the light characteristic with picture reproducing, and the gamma characteristic of input image signal and CRT monitor (its gamma value is about 2.2) is matched.In addition, second Gamma correction represents to make the Gamma correction that in input image signal and the colour liquid crystal display device 1 red, the green and blue transmissison characteristic that respectively applies voltage is matched and carried out.
Gray scale source circuit 3 as shown in Figure 14, is included in reference voltage V
AaThe resistance 8 of connecting between terminal and the earth terminal
1To 8
19, and voltage follower 9
1To 9
17, its each input end is connected to resistance adjacent one another are 8
1To 8
19Between tie point.3 pairs of resistance adjacent one another are 8 of gray scale source circuit
1To 8
19Between each tie point place produce in order to carry out rough each the grayscale voltage V that proofreaies and correct of second gamma
0To V
17Amplify and buffer memory, and it is fed to data electrode driver circuit 4.Data electrode driver circuit 4 as shown in Figure 14, mainly comprises 10,8 DAC of multiplexer (MPX) (digital-analog convertor) and voltage follower 12
1To 12
384MPX10 is according to the revertive pulsing POL that provides from control circuit 2, from presenting the grayscale voltage V from gray scale source circuit 3
0To V
17In switch and one group of grayscale voltage V
0To V
8Or one group of grayscale voltage V
9To V
17, and institute's switched voltage is fed to DAC11.DAC11 is according to the described group of grayscale voltage V that presents from MPX10
0To V
8Or described group of grayscale voltage V
9To V
17, to being all 8 the red data D of correction
RG, proofread and correct green data D
GGWith the blue data D of correction
BGCarrying out above-mentioned second proofreaies and correct roughly.Then, DAC11 will be through the rough red data D of correction that proofreaies and correct of second gamma
RG, proofread and correct green data D
GGWith the blue data D of correction
BGConvert the blue signal of simulated data red signal, the green signal of simulated data and simulated data to, then it is fed to each corresponding voltage follower 12
1To 12
384Each voltage follower 12
1To 12
384The green signal of data red signal, data presented from DAC11 and the blue signal of data are amplified and buffer memory, and will be through amplifying and the signal of buffer memory be fed to each corresponding data electrode in the colour liquid crystal display device 11.Scan electrode driving circuit 5 is according to from the control circuit 2 vertical scanning pulse P that presents
VTiming, produce sweep signal successively and successively the signal that is produced be applied to each corresponding scan electrode in the colour liquid crystal display device 1.
As mentioned above, in traditional liquid crystal display device, 2 pairs of control circuits are presented from the outside is all each red data D of 8
R, green data D
GWith blue data D
BCarry out first Gamma correction separately and dividually and second gamma is proofreaied and correct roughly.Curve " a " expression is presented from the outside among supposition Figure 15 below is all each red data D of 8
R, green data D
GWith blue data D
BGamma characteristic (gray scale-normalization light characteristic), and supposition carry out first Gamma correction so that among input data and Figure 15 the gamma characteristic (gray scale-normalization light characteristic, gamma value are about 2.2) of CRT monitor shown in the curve " b " match.In Figure 15, normalization brightness represents that the brightness that produces is the relative brightness of 1 o'clock gained when showing maximum gray scale (8 also is 255 gray levels).
Therefore, the red data D of correction that exports from control circuit 2
RG, proofread and correct green data D
GGWith the blue data D of correction
BGGamma characteristic, shown in curve among Figure 15 " c ", almost match with the gamma characteristic (gamma value is about 2.2) of CRT monitor shown in the curve among Figure 15 " b ".Yet, as shown in Figure 16, when curve " b " and " c " being gone up part between for example 150 gray levels and 160 gray levels and amplify, between the value on curve " b " and " c " and incomplete the coupling.In addition, in Figure 16, although the relation of gray scale and normalization brightness by periodic inversion, this is because the error of measured value causes, and is identical in theory in the value of inversion section.This be because, owing to be all 8 red data D
R, green data D
GWith blue data D
BBe converted into the red data D of correction by arithmetical operation
RG, proofread and correct green data D
GGWith the blue data D of correction
BGSo, do not have the gray level of initial conversion, so can only convert immediate gray level to.This causes carrying out the Gamma correction infringement of the gained gamma characteristic linearity afterwards.
Consequently, for example, as shown in Figure 17, when the image of its display brightness linear increase of direction from left to right in Figure 17 is presented in the colour liquid crystal display device 1, when although gray level is initial should along among Figure 17 from left to right direction increase gradually, yet the gray level on right side equals the gray level in left side, thereby causes showing vertical strip.Therefore, traditional LCD can not be as the display device of the medical treatment electronic equipment that needs special high resolution displayed image.As if for head it off, can adopt increases red data D
R, green data D
GWith blue data D
BThe method of figure place, yet this method causes the circuit scale of whole liquid crystal display device to become big and expensive.
In addition, in above-mentioned traditional liquid crystal display device, be all 8 red data D
R, green data D
GWith blue data D
BOnly be converted into the red data D of the correction that is all 8
RG, proofread and correct green data D
GGWith the blue data D of correction
BGTherefore, traditional liquid crystal display device has following shortcoming, the frequency characteristic of the timing signal of promptly can not solve environmental change that relevant environment temperature causes, ambient lighting, presenting from the outside, with the problem such as discrete of the variation of corresponding colour liquid crystal display device 1 gamma characteristic of brightness backlight that light beam is provided from colour liquid crystal display device 1 rear portion and the gamma characteristic that colour liquid crystal display device 1 manufacture process, produces.Above-mentioned these shortcomings also result from the driving circuit of monochromatic liquid crystal display with the same manner.
Summary of the invention
Consider above-mentioned, the object of the present invention is to provide a kind of method that is used to drive LCD, it can prevent to take place the reduction of the gamma characteristic linearity after carrying out Gamma correction, can realize the demonstration of high quality image with simple and structure at a low price, and can solve and environmental change, the timing signal frequency characteristic, variation with the corresponding colour liquid crystal display device gamma characteristic of backlight illumination, perhaps the gamma characteristic that produces in the colour liquid crystal display device manufacture process disperses and waits relevant problem, and a kind of liquid crystal display device is provided, and a kind of monitor that is provided with this liquid crystal display device.
According to a first aspect of the invention, provide a kind of method that is used to drive LCD, having comprised:
First step obtains the Gamma correction data, will add in order to the information that repeatedly changes each described digital of digital video data gray scale on it when digital of digital video data is carried out Gamma correction; And
Second step, by carrying out the many a plurality of gray scales of gray scale number that Frame-rate Control comes expression ratio to be expressed by described digital of digital video data, thereby produce the data-signal be used for repeatedly changing each described digital of digital video data gray scale, and the data-signal of described generation is fed to data electrode in the LCD successively according to described Gamma correction data.
In aforementioned, optimal way has by by the substep that obtains described Gamma correction data with the most close gray scale that two gray level approximate treatment of required brightness level in the described LCD gamma characteristic are provided for wherein said first step.
And optimal way is, wherein in described first step, reads by above-mentioned substep for each described digital of digital video data and to obtain and to be stored in described Gamma correction data in the storage medium in advance.
And, optimal way is, wherein in described first step, by the brightness adopting first substep to measure when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD, to obtain to calculate the gamma characteristic of described LCD, and for described gamma characteristic and required gamma characteristic are matched, by adopting second substep, that is, if to gray level n
0The gray level of carrying out the Gamma correction acquisition is an integer, and the gray scale that then adopts described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray scale that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness level in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (1) is obtained is as new gray level n
1If, and described gray level n
0Be minimal gray level or maximum gray scale, then adopt described gray level n
0As new gray level n
1And do not carry out described Gamma correction, obtain described Gamma correction data thus:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (1)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain.
And optimal way is, wherein in described first step, reads by above-mentioned first and second substeps for each described digital of digital video data and to obtain and to be stored in described Gamma correction data in the storage medium in advance.
And, optimal way is, wherein in described first step, obtain the Gamma correction data, when described digital of digital video data is carried out Gamma correction, will add on it, and it is carried out gray correction so that the voltage of described data-signal described data-signal when shadow tone is provided is in positive frame process or presents and difference in negative frame process in order to the information that repeatedly changes each described digital of digital video data gray scale.
And optimal way is, wherein said first step has by by the substep that obtains described Gamma correction data with the most close gray scale that two gray level approximate treatment of required brightness level in the described LCD gamma characteristic are provided.
And optimal way is, wherein in described first step, reads by above-mentioned substep for each described digital of digital video data and to obtain and to be stored in described Gamma correction data in the storage medium in advance.
And, optimal way is, wherein in described first step, by adopting first substep, the brightness that measurement obtains when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD is to calculate the gamma characteristic of described LCD, by adopting one second substep, measure as each shadow tone n
xUsed common electric voltage V when being presented on the described LCD
xSo and calculating common electric voltage V when the gray scale as benchmark is presented on the described LCD
REFWith measured common electric voltage V
xDifference as DC voltage V
DCx,, measure as described shadow tone n by adopting one the 3rd substep
xBe fed to the data-signal V of described data electrode when being presented on the described LCD
Nx,, match for making described gamma characteristic and required gamma characteristic, if to gray level n by adopting one the 4th substep
0The gray scale of carrying out the Gamma correction acquisition is an integer, and the gray scale that then adopts described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray scale that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (2) is obtained is as new gray scale n
1, and under the situation of minimal gray level and maximum gray scale, adopt described gray level n
0As described new gray scale n
1, and by adopting one the 5th substep, when by not carrying out the described gray level n of gray correction
1Be applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | V
N1+| and the data-signal of in negative frame process, presenting | V
N1-| with carry out the described gray level n of gray correction
xBe applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | U
N1+| and the data-signal of in negative frame process, presenting | U
N1-| when derived equation (3) and (4), and adopting the data-signal of in positive frame process, presenting | U
N1+| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R+And adopt and work as the data-signal of presenting in the negative frame process | U
N1-| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R-Situation under, if described gray level n
R+With gray level n
R-Be integer and be minimal gray level or maximum gray scale, then adopt described gray level n
R+And n
R-As gray scale, if described gray level n
R+With gray level n
R-Be not integer, then adopt will with data-signal described in the described data-signal gamma characteristic of described LCD is provided | U
N1+| and | U
N1-| hithermost two the gray level n that in positive frame process, present of gray level
C+And n
D+And two gray level n that in negative frame process, present
C-And n
D-The gray level that substitution equation (5) and (6) are obtained is as gray level n
R+And n
R-, obtain described Gamma correction data thus:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (2)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain:
| U
N1+|=|| V
N1+|-V
DCx| ... equation (3)
| U
N1-|=|| V
N1-|+V
DCx| ... equation (4)
n
R+=(| U
N1+|+| U
Nd+| n
c-| U
Nc+| n
d)/(| U
Nd+|-| U
Nc+|) ... equation (5)
Wherein " | U
Nc+| " and " | U
Nd+| " be respectively when each the described gray level n that provides in the positive frame process is provided in described LCD data gray signal characteristic
cAnd n
dThe time data-signal that adopted:
n
R-=(| U
N1-|+| U
Nd-| n
c-| U
Nc-| n
d)/(| U
Nd-|-| U
Nc-|) ... equation (6)
Wherein " | U
Nc-| " and " | U
Nd-| " be respectively when in described LCD data gray signal characteristic, being presented at each the described gray level n that provides in the frame process is provided
cAnd n
dThe time data-signal that adopted.
And optimal way is, wherein in described first step, reads by above-mentioned each substep for each digital of digital video data and to obtain and to be stored in described correction data in the storage medium in advance.
And, optimal way is, wherein said Gamma correction can be selected from different Gamma corrections, comprise and be used to reach and the corresponding to Gamma correction of change that causes described LCD gamma characteristic by variation of ambient temperature, be used to reach and the corresponding to Gamma correction of change that causes described LCD gamma characteristic by the ambient lighting variation, be used to reach and the corresponding to Gamma correction of described LCD gamma characteristic that changes with the timing signal frequency characteristic, be used to reach with in order to providing the brightness backlight of light beam to change the corresponding to Gamma correction of described LCD gamma characteristic that changes from described LCD rear portion to it, and be used for reaching the gamma characteristic that takes place with the described LCD manufacture process corresponding to Gamma correction that disperses.
And optimal way is that wherein said digital of digital video data comprises red data, green data and blue data, and described Gamma correction carries out independently for each described red data, green data and blue data.
And, optimal way is, wherein said Gamma correction comprise to described red data, green data and blue data carry out to provide arbitrarily with first Gamma correction of the corresponding picture reproducing light characteristic of input imagery brightness with so that second Gamma correction that red in input image signal and the described LCD, the green and blue transmissison characteristic that respectively applies voltage is complementary.
And optimal way is, wherein said information is to be used to select the data of pattern with the described gray scale that repeatedly changes each Gamma correction data.
According to a second aspect of the invention, provide a kind of liquid crystal display device, having comprised:
LCD;
Gamma correction circuit is used to obtain the Gamma correction data, will add in order to the information that repeatedly changes each described digital of digital video data gray scale on it when digital of digital video data is carried out Gamma correction; And
Data-signal produces circuit, be used for coming expression ratio by the many a plurality of gray scales of described digital of digital video data institute representing gradation quantity, be used for repeatedly changing the data-signal of each described digital of digital video data gray scale and the data-signal of described generation being fed to successively the data electrode of LCD according to described Gamma correction data thereby produce by carrying out Frame-rate Control.
In aforementioned, optimal way is that wherein said gamma correction circuit is by obtaining described Gamma correction data by the most close gray level of two gray level approximate treatment of required brightness level in the described LCD gamma characteristic that provides of usefulness.
And, optimal way is, comprising a correction data memory circuit, wherein store by by with the most close described Gamma correction data that gray level obtained that two gray level approximate treatment of required brightness level in the described LCD gamma characteristic are provided, and, wherein gamma correction circuit reads the Gamma correction data of each digital of digital video data from the correction data memory circuit, and data of reading are delivered to data-signal produces circuit.
And, optimal way is, wherein said gamma correction circuit is by measuring brightness when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD to calculate the gamma characteristic of described LCD, and for described gamma characteristic and required gamma characteristic are matched, and, if to gray level n
0The gray scale of carrying out the Gamma correction acquisition is an integer, and the gray scale that then adopts described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray scale that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that the gray level of required brightness in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (7) is obtained is as new gray level n
1If, and described gray level n
0Be minimal gray level or maximum gray scale, then adopt described gray scale n
0As new gray level n
1And do not carry out described Gamma correction, obtain described Gamma correction data thus:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (7)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain.
Optimal way is, comprising a correction data memory circuit, be used for storing in advance the described Gamma correction data of following acquisition, promptly by measuring brightness when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD to calculate the gamma characteristic of described LCD, and for described gamma characteristic and required gamma characteristic are matched, if to gray level n
0The gray scale of carrying out the Gamma correction acquisition is an integer, and the gray scale that then adopts described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray level that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness level in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (8) is obtained is as new gray level n
1If, and described gray scale n
0Be minimal gray level or maximum gray scale, then adopt described gray level n
0As new gray level n
1And do not carry out described Gamma correction, obtain described Gamma correction data thus, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal and produces circuit from described correction data memory circuit:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (8)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain.
And, optimal way is, wherein said gamma correction circuit obtains the Gamma correction data, when described digital of digital video data is carried out Gamma correction, will add on it, and it is carried out gray correction so that the voltage of described data-signal described data-signal when shadow tone is provided is in positive frame process or presents and difference in negative frame process in order to the information that repeatedly changes each described digital of digital video data gray scale.
And optimal way is that wherein said gamma correction circuit is by obtaining described Gamma correction data by the most close gray level of two gray level approximate treatment of required brightness level in the described LCD gamma characteristic that provides of usefulness.
And, optimal way is, comprising a correction data memory circuit, wherein store by by with the most close described Gamma correction data that gray level obtained that two gray level approximate treatment of required brightness level in the described LCD gamma characteristic are provided, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal from described correction data memory circuit and produces circuit.
And, optimal way is, wherein said gamma correction circuit is worked as each shadow tone n by measuring the brightness obtain to calculate the gamma characteristic of described LCD when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD by measuring
xUsed common electric voltage V when being presented on the described LCD
xAnd calculate used common electric voltage V when the gray scale as benchmark is presented on the described LCD
REFWith measured common electric voltage V
xDifference as DC voltage V
DCx, by measuring as described shadow tone n
xBe fed to the data-signal V of described data electrode when being presented on the described LCD
Nx, and for described gamma characteristic and required gamma characteristic are matched, if to gray level n
0Carrying out the gray scale that Gamma correction obtains is integer, and the gray scale by adopting described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray level that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness level in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (9) is obtained is as new gray level n
1, and under the situation of minimal gray level and maximum gray scale, then adopt described gray level n
0As described new gray scale n
1, and, when by the described gray level n that does not carry out gray correction
1Be applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | V
N1+| and the data-signal of in negative frame process, presenting | V
N1-| with when carrying out the described gray level n of gray correction
xBe applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | U
N1+| and the data-signal of in negative frame process, presenting | U
N1-| when derived equation (10) and (11), and adopting the data-signal of in positive frame process, presenting | U
N1+| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R+And adopt and work as the data-signal of presenting in the negative frame process | U
N1-| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R-Situation under, if described gray level n
R+With gray level n
R-Be integer and be minimal gray level or maximum gray scale, then adopt described gray level n
R+And n
R-As gray scale, if described gray level n
R+With gray level n
R-Be not integer, then adopt will with data-signal described in the described data-signal gamma characteristic of described LCD is provided | U
N1+| and | U
N1-| hithermost two the gray level n that in positive frame process, present of gray level
C+And n
D+And two gray level n that in negative frame process, present
C-And n
D-The gray level that substitution equation (12) and (13) are obtained is as gray level n
R+And n
R-, obtain described Gamma correction data thus:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (9)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain:
| U
N1+|=|| V
N1+|-V
DCx| ... equation (10)
| U
N1-|=|| V
N1-|+V
DCx| ... equation (11)
n
R+=(| U
N1+|+| U
Nd+| n
c-| U
Nc+| n
d)/(| U
Nd+|-| U
Nc+|) ... equation (12)
Wherein " | U
Nc+| " and " | U
Nd+| " be respectively when each the described gray level n that provides in the positive frame process is provided in described LCD data gray signal characteristic
cAnd n
dThe time data-signal that adopted:
n
R-=(| U
N1-|+| U
Nd-| n
c-| U
Nc-| n
d)/(| U
Nd-|-| U
Nc-|) ... equation (13)
Wherein " | U
Nc-| " and " | U
Nd-| " be respectively when in described LCD data gray signal characteristic, being presented at each the described gray level n that provides in the frame process is provided
cAnd n
dThe time data-signal that adopted.
And, optimal way is, wherein said gamma correction circuit to calculate the gamma characteristic of described LCD, is worked as each shadow tone n by measuring by the brightness of measurement when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD
xUsed common electric voltage V when being presented on the described LCD
xAnd calculate used common electric voltage V when the gray scale as benchmark is presented on the described LCD
REFWith measured common electric voltage V
xDifference as DC voltage V
DCx, by measuring as described shadow tone n
xBe fed to the data-signal V of described data electrode when being presented on the described LCD
Nx, and for described gamma characteristic and required gamma characteristic are matched, if to gray level n
0Carrying out the gray scale that Gamma correction obtains is integer, and the gray scale by adopting described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray level that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness level in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (14) is obtained is as new gray level n
1, and under the situation of minimal gray level and maximum gray scale, then adopt described gray level n
0As described new gray level n
1, and, when by the described gray level n that does not carry out gray correction
1Be applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | V
N1+| and the data-signal of in negative frame process, presenting | V
N1-| with when carrying out the described gray level n of gray correction
xBe applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | U
N1+| and the data-signal of in negative frame process, presenting | U
N1-| when derived equation (15) and (16), and adopting the data-signal of in positive frame process, presenting | U
N1+| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R+And adopt and work as the data-signal of presenting in the negative frame process | U
N1-| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R-Situation under, if described gray level n
R+With gray level n
R-Be integer and be minimal gray level or maximum gray scale, then adopt described gray level n
R+And n
R-As gray scale, if described gray level n
R+With gray level n
R-Be not integer, then adopt will with data-signal described in the described data-signal characteristic of described LCD gray scale is provided | U
N1+| and | U
N1-| hithermost two the gray level n that in positive frame process, present of gray level
C+And n
D+And two gray level n that in negative frame process, present
C-And n
D-The gray level that substitution equation (17) and (18) are obtained is as gray level n
R+And n
R-, obtain described Gamma correction data thus, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal and produces circuit from described correction data memory circuit:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (14)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain:
| U
N1+|=|| V
N1+|-V
DCx| ... equation (15)
| U
N1-|=|| V
N1-|+V
DCx| ... equation (16)
n
R+=(| U
N1+|+| U
Nd+| n
c-| U
Nc+| n
d)/(| U
Nd+|-| U
Nc+|) ... equation (17)
Wherein " | U
Nc+| " and " | U
Nd+| " be respectively when each the described gray level n that provides in the positive frame process is provided in described LCD data gray signal characteristic
cAnd n
dThe time data-signal that adopted:
n
R-=(| U
N1-|+| U
Nd-| n
c-| U
Nc-| n
d)/(| U
Nd-|-| U
Nc-|) ... equation (18)
Wherein " | U
Nc-| " and " | U
Nd-| " be respectively when in described LCD data gray signal characteristic, being presented at each the described gray level n that provides in the frame process is provided
cAnd n
dThe time data-signal that adopted.
And, optimal way is, comprising a correction data memory circuit, wherein storage in advance is used to reach and causes described LCD gamma characteristic to change the Gamma correction data of corresponding to Gamma correction by variation of ambient temperature, be used to reach and the Gamma correction data that change the corresponding to Gamma correction of change that causes described LCD gamma characteristic by ambient lighting, be used to reach Gamma correction data with the corresponding to Gamma correction of described LCD gamma characteristic that changes with the timing signal frequency characteristic, be used to reach with in order to provide the brightness backlight of light beam to change the Gamma correction data of the corresponding to Gamma correction of described LCD gamma characteristic that changes from described LCD rear portion to it, and the Gamma correction data that are used for reaching the discrete corresponding to Gamma correction of gamma characteristic that takes place with described LCD manufacture process, and the correcting pattern that will be presented by the outside selects the selected Gamma correction feeds of data of data to described gamma correction circuit, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal from described correction data memory circuit and produces circuit.
And, optimal way is, wherein said correction data memory circuit is stored in advance and is used to reach and cause described LCD gamma characteristic to change the Gamma correction data of corresponding to Gamma correction by variation of ambient temperature, be used to reach and the Gamma correction data that change the corresponding to Gamma correction of change that causes described LCD gamma characteristic by ambient lighting, be used to reach Gamma correction data with the corresponding to Gamma correction of described LCD gamma characteristic that changes with the timing signal frequency characteristic, be used to reach with in order to provide the brightness backlight of light beam to change the Gamma correction data of the corresponding to Gamma correction of described LCD gamma characteristic that changes from described LCD rear portion to it, and the Gamma correction data that are used for reaching the discrete corresponding to Gamma correction of gamma characteristic that takes place with described LCD manufacture process, and the correcting pattern that will be presented by the outside selects the selected Gamma correction feeds of data of data to described gamma correction circuit, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal from described correction data memory circuit and produces circuit.
And optimal way is that wherein said digital of digital video data comprises red data, green data and blue data, and described Gamma correction carries out independently for each described red data, green data and blue data.
And, optimal way is, wherein said Gamma correction comprise to described red data, green data and blue data carry out to provide arbitrarily with first Gamma correction of the corresponding picture reproducing light characteristic of input imagery brightness with so that second Gamma correction that red in input image signal and the described LCD, the green and blue transmissison characteristic that respectively applies voltage is complementary.
In addition, optimal way is that wherein said information is to be used to select pattern repeatedly to change the data of the described gray scale of each Gamma correction data.
According to a third aspect of the invention we, provide a kind of monitor with above-mentioned liquid crystal display device.
Pass through said structure, by obtaining when digital of digital video data is carried out Gamma correction, will add to the Gamma correction data on it in order to the information that repeatedly changes each described digital of digital video data gray scale, produce then and be used for repeatedly changing the data-signal of each described digital of digital video data gray scale and the data-signal of described generation being fed to successively the data electrode of LCD according to described Gamma correction data, carry out Frame-rate Control in this way, thus can expression ratio by the many a plurality of gray scales of described digital of digital video data institute's representing gradation quantity.This makes it possible to prevent to take place with simple and structure at a low price the reduction of the gamma characteristic linearity after carrying out Gamma correction.Consequently, can realize the demonstration of high quality image.
And, pass through said structure, obtain the Gamma correction data, when described digital of digital video data is carried out Gamma correction, will add on it, and it is carried out gray correction so that the voltage of described data-signal described data-signal when shadow tone is provided is in positive frame process or presents and difference in negative frame process in order to the information that repeatedly changes each described digital of digital video data gray scale.Therefore, make the simple in structure of the data electrode driver circuit that uses among the present invention, and correspondingly can reduce chip area.This makes structure of the present invention can satisfy the latest requirement of saving the liquid crystal display device space fully.
In addition, the Gamma correction that adopts in the inventive method can be selected from different Gamma corrections, comprise and be used to reach and the corresponding to Gamma correction of change that causes described LCD gamma characteristic by variation of ambient temperature, be used to reach and the corresponding to Gamma correction of change that causes described LCD gamma characteristic by the ambient lighting variation, be used to reach and the corresponding to Gamma correction of described LCD gamma characteristic that changes with the timing signal frequency characteristic, be used to reach with in order to providing the brightness backlight of light beam to change the corresponding to Gamma correction of described LCD gamma characteristic that changes from described LCD rear portion to it, and be used for reaching the gamma characteristic that takes place with the described LCD manufacture process corresponding to Gamma correction that disperses.This make it possible to solve change with environmental change such as environment temperature ambient lighting, timing signal frequency characteristic, by backlight illumination due to relevant problems such as the variation of LCD gamma characteristic and the gamma characteristic that produces in the LCD manufacture process is discrete.
Brief description of drawings
Can clearer above-mentioned and other purposes, advantage and characteristic of the present invention from the explanation that provides below in conjunction with accompanying drawing.In the accompanying drawing:
Fig. 1 adopts the schematic block diagram of the liquid crystal display device structure of first embodiment of the invention liquid crystal display driving method for expression;
Fig. 2 is the synoptic diagram of Gamma correction data storage circuitry 22 structures of expression pie graph 1 liquid crystal display device;
Fig. 3 represents a routine gamma characteristic of CRT monitor and colour LCD device;
Fig. 4 is the enlarged drawing of part " A " among Fig. 3;
Fig. 5 represents a routine data layout of 10 first correction data;
Fig. 6 represents that an example is used to export the computing of 10 second correction datas;
Fig. 7 adopts the schematic block diagram of the liquid crystal display device structure of second embodiment of the invention liquid crystal display driving method for expression;
Fig. 8 constitutes the schematic block diagram of the structure of the Gamma correction data storage circuitry 31 of second embodiment of the invention liquid crystal display device and gamma correction circuit 32 for expression;
Fig. 9 represents that an example that adopts in the second embodiment of the invention is to be used to obtain DC voltage V under the 127 gray level situations in the benchmark gray scale
DCxMethod;
Figure 10 represents a routine characteristic of the data-signal gray scale that adopts in the second embodiment of the invention;
Figure 11 represents to adopt in the second embodiment of the invention | V
N1+|, | V
N1-|, | U
N1+|, | U
N1-| with common electric voltage V
ComBetween the relation an example;
Figure 12 is the enlarged drawing of part " B " among Figure 10;
Figure 13 is the schematic block diagram of disclosed conventional liquid crystal part structure among the expression one routine Japanese Patent Application Publication No.2001-134242;
Figure 14 constitutes the schematic block diagram of structure of control circuit 2, gray scale source circuit 3 and the data electrode driver circuit 4 of conventional liquid crystal part separately for expression;
Figure 15 represent a routine CRT monitor gamma characteristic, digital image data gamma characteristic and when the latter and the former match the gamma characteristic of gained;
Figure 16 represents the enlarged drawing of the part of two curves shown in Figure 15; And
Figure 17 represents to be used for a routine synoptic diagram that shows of gray scale.
DETAILED DESCRIPTION OF THE PREFERRED
Further describe with different embodiment with reference to the accompanying drawings and implement best mode of the present invention.
First embodiment
Fig. 1 adopts the schematic block diagram of the liquid crystal display device structure of first embodiment of the invention liquid crystal display driving method for expression.In Fig. 1, represent with identical number mark with the corresponding component that has identical function among Figure 13, and correspondingly omit its explanation.The liquid crystal display device that substitutes control circuit 2, gray scale source circuit 3 and data electrode driver circuit 4, the first embodiment shown in Figure 13 comprises new digital of digital video data memory circuit 21, Gamma correction data storage circuitry 22, gamma correction circuit 23, FRC (Frame-rate Control control) circuit 24, control circuit 25 and data electrode driver circuit 26.
Digital of digital video data memory circuit 21, is used to store digital of digital video data and comprises 8 the red data D of being all that presents from the outside such as RAM formations such as (random access memory) by semiconductor memory
R, green data D
GWith blue data D
BGamma correction data storage circuitry 22 by semiconductor memory such as ROM (ROM (read-only memory)), RAM or nonvolatile semiconductor memory such as refreshing (flush) EEPROM formations such as (electrically erasable preface ROM).Gamma correction data storage circuitry 22 store in advance be all 10 and with the corresponding red correction data D of 8 types of correcting patterns (pattern 1 is to pattern 8)
RR, green correction data D
GRWith blue correction data D
BR, and the corresponding red correction data D of correcting pattern that selects data DP to be selected with the 3 bit correction patterns that provide by the outside is provided separately
RR, green correction data D
GRWith blue correction data D
BRAs under the conventional situation, employing respectively is 10 red correction data D
RR, green correction data D
GRWith blue correction data D
BRPrevent that the gamma characteristic linearity is at the red data D that is all 8
R, green data D
GWith blue data D
BReduced after the Gamma correction, thereby produced the red data D of correction that is all 8
RG, proofread and correct green data D
GGWith the blue data D of correction
BG
8 types correcting pattern comprises the correcting pattern that for example is used to make picture intelligence and variation corresponding to colour liquid crystal display device 1 gamma characteristic of liquid crystal display device variation of ambient temperature to be complementary, the correcting pattern that is used to make the variation of picture intelligence and colour liquid crystal display device 1 gamma characteristic that changes corresponding to the liquid crystal display device ambient lighting to be complementary, the correcting pattern that colour liquid crystal display device 1 gamma characteristic that is used to make picture intelligence and changes with the timing signal frequency characteristic variations is complementary, the correcting pattern that colour liquid crystal display device 1 gamma characteristic that is used to make picture intelligence and changes with the backlight illumination variation is complementary, the discrete correcting pattern that is complementary of the gamma characteristic that is used for making picture intelligence and colour liquid crystal display device 1 manufacture process to take place, or the like.
The red correction data D that is used for each correcting pattern
RR, green correction data D
GRWith blue correction data D
BRGamma characteristic by the colour liquid crystal display device 1 of gained when measuring frequency characteristic when the environment temperature of the liquid crystal display device that is in installment state or ambient lighting, timing signal, backlight illumination variation in advance, perhaps the gamma characteristic that takes place in colour liquid crystal display device 1 manufacture process is discrete, and in order to form by carrying out the value that Gamma correction removes this variation or discrete influence.That is to say that the Gamma correction of present embodiment comprises above-mentioned first Gamma correction and second Gamma correction.
Fig. 2 is the synoptic diagram of Gamma correction data storage circuitry 22 structures of expression pie graph 1 liquid crystal display device.As shown in Figure 2, each correcting pattern is stored red correction data D
RR, green correction data D
GRWith blue correction data D
BRLow 10 A9 to A0 in the address distribute 0 to 255 (decimal system) as red correction data D
RRStorage area, 256 to 511 (decimal systems) are distributed as green correction data D
GRStorage area, and 512 to 767 (decimal systems) are distributed as blue correction data D
BRStorage area.At high 3 A12 to A10, with the storage area of 0 (decimal system) distribution as pattern 1, with the storage area of 1 (decimal system) distribution as pattern 2, with the storage area of 2 (decimal systems) distribution as pattern 3, with the storage area of 3 (decimal systems) distribution as pattern 4, with the storage area of 4 (decimal systems) distribution as pattern 5, with the storage area of 5 (decimal systems) distribution as pattern 6, with the storage area of 6 (decimal systems) distribution as pattern 7, and with the storage area of 7 (decimal systems) distribution as pattern 8.Therefore, above-mentioned correcting pattern is selected the value of data DP corresponding to high 3 A12 to A10 in the positive pattern of selecting a school to be selected.
The following describes and be used to calculate above-mentioned red correction data D
RR, green correction data D
GRWith blue correction data D
BRMethod.
(1) at first, measure the brightness that can obtain when data-signal when 0 to 255 gray level is applied to the data electrode of colour liquid crystal display device 1, with the gamma characteristic of calculating colour liquid crystal display device.Herein, Fig. 3 represents an example of the gamma characteristic of calculating with curve " a ".In Fig. 3, the gamma characteristic that curve " b " expression is complementary by the gamma characteristic (gamma value is about 2.2) of carrying out Gamma correction and for example CRT monitor.
(2) secondly, carry out Gamma correction by following method, so that the gamma characteristic of colour liquid crystal display device 1 and required gamma characteristic for example the gamma characteristic of CRT monitor be complementary, even also the normalization brightness of colour liquid crystal display device 1 gamma characteristic equals the normalization brightness of the CRT monitor gamma characteristic of certain gray level.As shown in Figure 3, in the curve " b " of expression CRT monitor gamma characteristic, be " n in gray level
0" time, its normalization brightness is " m
0", and in the curve " a " of expression colour liquid crystal display device 1 gamma characteristic, make its normalization brightness be " m
0" gray level be " n
1".Therefore, as input gray grade " n
0" time, output gray level " n
1".Obtain gray level " n by following method
1".
(a) if to gray level " n
0" gray level of carrying out the Gamma correction gained is integer, the constant gray level " n that is used as of gained gray level former state then
1".
(b) if to gray level " n
0" gray level of carrying out the Gamma correction gained is not integer, then by will the most closely making normalization brightness become " m in the curve " a " of expression colour liquid crystal display device 1 gamma characteristic
0" two gray level " n of gray level
a" and " n
b" (see figure 4) substitution equation (101), the gained gray level is used as gray scale " n
1".Fig. 4 is the enlarged drawing of part " A " among Fig. 3.In Fig. 4, straight line L is the near linear of curve shown in Fig. 3 " a ".
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (101)
" m wherein
a" expression when gray level for the curve " a " of expression colour liquid crystal display device 1 gamma characteristic in " n
a" time normalization brightness that can obtain, " m
b" expression when gray level for the curve " a " of expression colour liquid crystal display device 1 gamma characteristic in " n
b" time normalization brightness that can obtain.
The following describes the method that obtains equation (101).In general, straight line " L " is represented by equation (102).
Y=α x+ β ... equation (102)
Wherein " α " represents slope, and " β " represents intercept.By with two coordinate (n shown in Fig. 4
a, m
a) and (n
b, m
b) value substitution equation (102), can derived equation (103) and (104):
m
a=α n
a+ β ... equation (103)
m
b=α n
b+ β ... equation (104)
Deduct equation (103) from equation (104), and rearrange at slope α, can derived equation (105):
α=(m
b-m
a)/(n
b-n
a) ... equation (105)
And, equation (103) is added to equation (104), and substitution equation (105) and rearrange at intercept β, can derived equation (106):
β=(m
aN
b-m
bN
a)/(n
b-n
a) ... equation (106)
Because gray level n
aAnd n
bBe value located adjacent one another, so concern therebetween by equation (107) and provide:
n
b-n
a=1 ... equation (107)
Therefore, with equation (107) substitution equation (105) and equation (106), can get equation (108) and (109):
α=m
b-m
aEquation (108)
β=m
aN
b-m
bN
aEquation (109)
With equation (108) and (109) substitution equation (102), can get equation (110):
Y=(m
b-m
a) x+m
aN
b-m
bN
aEquation (110)
With coordinate (n
1, m
0) value substitution equation (110) and at gray level " n
1" rearrange, can get equation (101).
(c) be that 0 gray level and maximum gray scale are that 255 gray levels are not carried out Gamma correction to the minimal gray level, they are same as before as gray scale.
Then, with 8 gray level " n of gained
1" (decimal system) substitution equation (111), the calculating gray level " n '
1" (decimal system):
N '
1=INT (4n
1+ 0.5) ... equation (111)
Wherein the integral part of arithmetic operation results in the bracket is only adopted in " INT () " expression.
By using above-mentioned computing method, calculate the red correction data D of all correcting patterns
RR, green correction data D
GRWith blue correction data D
BR
24 pairs in FRC circuit from gamma correction circuit 23 present respectively be 10 first proofread and correct red data D
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1(see figure 2) is carried out Frame-rate Control, convert thereof into respectively be 8 second proofread and correct red data D
RG2, second proofread and correct green data D
GG2With the blue data D of second correction
BG2, and institute's translation data is fed to data electrode driver circuit 26.Frame-rate Control is the driving method that is used for the many a plurality of gray levels of expression ratio number of grey levels to be shown when driving colour liquid crystal display device 1 with common driving method.For example, hot data D
R, green data D
GWith blue data D
BEach units when being " 8 ", if adopt common driving method, then can only express 255 gray levels.On the contrary, if constitute the red data D of digital of digital video data
R, green data D
GWith blue data D
BEach units be " 10 ", then can express 1024 gray levels.Yet, be configured such that the red data D that constitutes digital of digital video data when liquid crystal display device
R, green data D
GWith blue data D
BFigure place be " 10 " rather than " 8 " when initial, as mentioned above, then the circuit scale of whole liquid crystal display device becomes big, consequently, causes higher price.For head it off, according to present embodiment, by adopting Frame-rate Control, also, by utilizing the visual persistence effect of human eye, with red data D than long number
R, green data D
GWith blue data D
BExpressed gray level is compared more good gray scale can be with the red data D of less figure place
R, green data D
GWith blue data D
BShowed.In other words, when presenting vertical synchronizing signal S
VThe time, have an image of gray level " a " (" a " is natural number) and have another image of gray level " a+1 " with timing repetitive mode Alternation Display, these two images are considered as having an image of intermediate luminance between the brightness of brightness that display gray scale produces during for " a " visual and display gray scale generation during for " a+1 " visual (below be called＜a a+1〉brightness) by human eye.In addition, by presenting vertical synchronizing signal S
VThe time timing, after an image with gray level " a " shows once, if having another image of gray level " a+1 " shows twice with repetitive mode, then these two images are considered as having the brightness that produces during for " a+1 " image in display gray scale and display gray scale and are＜a, a+1 by human eye〉image of intermediate luminance between the brightness of generation during image.
Therefore, FRC circuit 24 is to apply above-mentioned vertical synchronizing signal S
VThe time timing to present from gamma correction circuit 23 respectively be 10 first proofread and correct red data D
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1(being referred to as " first correction data ") carries out Frame-rate Control, and these data second are proofreaied and correct red data D as what respectively be 8
RG2, second proofread and correct green data D
GG2With the blue data D of second correction
BG2(being referred to as " second correction data ") is fed to data electrode driver circuit 26.Specifically, in first correction data is 10 data layout, each data D1 to D0 corresponding with each low 2 B1 to B0 represents growth data, data presented when each data D9 to D2 representative corresponding with each most-significant byte B9 to B2 drives colour liquid crystal display device 1 with common driving method.
Fig. 6 represents to be suitable for exporting the algorithm of second correction data.That is to say that if be combined as " 00 " with low 2 the corresponding data D1 to D0 of first correction data, then corresponding with most-significant byte data D9 to D2 (gray level " a " is provided) is used as second correction data and is fed to data electrode driver circuit 26.If low 2 corresponding data D1 to D0 are combined as " 01 " with first correction data, then in first frame to the, three frame processes, the data D9 to D2 corresponding with most-significant byte (gray level " a " is provided) is used as second correction data and is fed to data electrode driver circuit 26, and in the 4th frame process, will the data D9 to D2 corresponding add 1 gained data (gray level " a+1 " is provided) and be fed to data electrode driver circuit 26 as second correction data with most-significant byte.In per four frame processes, repeat aforesaid operations.For example, in the first frame process, be output as after first correction data of still image, ignore in the back correction data to be imported in the three frame processes, and in second to the 4th frame process, will export data electrode driver circuit 26 to as second correction data for the data among first correction data.
Similarly, if low 2 corresponding data D1 to D0 are combined as " 10 " with first correction data, then in first frame and the second frame process, data D9 to D2 that will be corresponding with most-significant byte (having gray level " a ") is fed to data electrode driver circuit 26 as second correction data, and in the 3rd frame and the 4th frame process, will the data D9 to D2 corresponding add 1 gained data (having gray level " a+1 ") and be fed to data electrode driver circuit 26 as second correction data with most-significant byte.In per four frame processes, repeat aforesaid operations.If low 2 corresponding data D1 to D0 are combined as " 11 " with first correction data, then in the first frame process, data D9 to D2 that will be corresponding with most-significant byte (gray level " a " is provided) is used as second correction data and is fed to data electrode driver circuit 26, and in second frame to the, four frame processes, will the data D9 to D2 corresponding add 1 gained data (gray level " a+1 " is provided) and be fed to data electrode driver circuit 26 as second correction data with most-significant byte.In per four frame processes, repeat these operations.
In addition, about the more details of FRC circuit structure and operation, put down into 2-285391 referring to Japanese Patent Application Publication No. and put down into 5-249436 etc. with No..
Therefore, by introducing this FRC circuit, with the red data D that only increases the need processing
R, green data D
GWith blue data D
BThe situation of figure place is compared, and can easily construct liquid crystal display device with low cost.
Data electrode driver circuit 26 is according to all being the horizontal scanning pulse P that presents from control circuit 25
HWith revertive pulsing POL, will from FRC circuit 24 present be all 8 second proofread and correct red data D
RG2, second proofread and correct green data D
GG2With the blue data D of second correction
BG2Convert the blue signal of simulated data red signal, the green signal of simulated data and simulated data to, then institute's switching signal is fed to successively the counter electrode of colour liquid crystal display device 1.
The following describes the operation of liquid crystal display device with said structure.At first, when presenting the signal " 000 " (scale-of-two) that is used to select pattern shown in Fig. 21 from the outside and select data DP as correcting pattern, having address A12 to A0 from Gamma correction data storage circuitry 22, to read corresponding with pattern 1 successively for the storage area of " 0 " to " 767 " (decimal system) respectively be 10 red correction data D
RR, green correction data D
GRWith blue correction data D
BR, and data streams read is fed to gamma correction circuit 23.This pattern 1 is for being used to make input image signal and for example changing the correcting pattern that matches by the gamma characteristic of the colour liquid crystal display device 1 due to the liquid crystal display device variation of ambient temperature.
Then, when presenting from the outside by the red data D that is all 8
R, green data D
GWith blue data D
BDuring the digital of digital video data that constitutes, digital of digital video data is read out and is fed to gamma correction circuit 23 after once in being stored in digital of digital video data memory circuit 21.Gamma correction circuit 23 respectively is 10 red correction data D by using what present from Gamma correction data storage circuitry 22
RR, green correction data D
GRWith blue correction data D
BRTo what present from digital of digital video data memory circuit 21 respectively is 8 red data D
R, green data D
GWith blue data D
BCarry out Gamma correction and gray scale is provided.Then, gamma correction circuit 23 first is proofreaied and correct red data D with each Gamma correction result as what respectively be 10
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1Be fed to FRC circuit 24.
Then, 24 pairs in FRC circuit from gamma correction circuit 23 present respectively be 10 first proofread and correct red data D
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1Carry out Frame-rate Control, convert thereof into respectively be 8 second proofread and correct red data D
RG2, second proofread and correct green data D
GG2With the blue data D of second correction
BG2, and institute's translation data is fed to data electrode driver circuit 26.And control circuit 25 is according to the horizontal-drive signal S that presents from the outside
H, vertical synchronizing signal S
VWith clock CLK etc., produce horizontal scanning pulse P
H, vertical scanning pulse P
V, and revertive pulsing POL, and with these impulse feeding to data electrode driver circuit 26 and scan electrode driving circuit 5.Consequently, data electrode driver circuit 26 is according to the horizontal scanning pulse P that presents from control circuit 25
HWith revertive pulsing POL, will from FRC circuit 24 present be all 8 second proofread and correct red data D
RG2, second proofread and correct green data D
GG2With the blue data D of second correction
BG2Convert the blue signal of simulated data red signal, the green signal of simulated data and simulated data to, then each institute's switching signal is fed to successively the counter electrode of colour liquid crystal display device 1.In addition, scan electrode driving circuit 5 is according to the vertical scanning pulse P that is presented from control circuit 2
VTiming, produce sweep signal successively and each produced signal and be applied to each corresponding scan electrode in the colour liquid crystal display device 1.
By the above-mentioned operation of carrying out, even when the gamma characteristic of colour liquid crystal display device 1 changes owing to the variation of LCD environment temperature, also can on colour liquid crystal display device 1, show high-quality image.
Therefore, according to present embodiment, by 8 the red data D of being all in gamma correction circuit 23 to presenting from the outside
R, green data D
GWith blue data D
BCarry out Gamma correction and obtain respectively be 10 first proofread and correct red data D
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1In addition, 24 pairs in FRC circuit respectively is 10 the red data D of first correction
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1Carry out Frame-rate Control and proofread and correct red data D to convert thereof into second
RG2, second proofread and correct green data D
GG2With the blue data D of second correction
BG2This makes and can prevent to carry out after the Gamma correction reduction of the gamma characteristic linearity to take place with simple and structure at a low price, thereby makes it possible to realize that high-quality image shows.
In addition, according to present embodiment, storage and 8 types of corresponding red correction data D of correcting pattern in advance in Gamma correction data storage circuitry 22
RR, green correction data D
GRWith blue correction data D
BR, and will select the corresponding red correction data D of the selected correcting pattern of data DP with correcting pattern
RR, green correction data D
GRWith blue correction data D
BRBe fed to gamma correction circuit 23.This make the frequency characteristic of the timing signal that the liquid crystal display device of present embodiment can be presented in response to environmental changes such as environment temperature, ambient lightings, from the outside, change by backlight illumination due to the variation of colour liquid crystal display device 1 gamma characteristic or the gamma characteristic that colour liquid crystal display device 1 manufacture process, produces discrete.
Second embodiment
Fig. 7 adopts the schematic block diagram of the liquid crystal display device structure of second embodiment of the invention liquid crystal display driving method for expression.In Fig. 7, represent with identical number mark with the corresponding component that has identical function among Fig. 1, and correspondingly omit its explanation.The liquid crystal display device of Gamma correction data storage circuitry 22 shown in the alternate figures 1, gamma correction circuit 23 and control circuit 25, the second embodiment comprises new Gamma correction data storage circuitry 31, gamma correction circuit 32 and control circuit 33.The liquid crystal display device of present embodiment has the gray correction function, by when carrying out Gamma correction, depend on when shadow tone (halftone) is provided in positive frame process or feed signal whether in the negative frame process, make the blue voltage of signals of data red signal, the green signal of data and data different.In addition, the LCD of present embodiment is as hereinafter described according to the content that is stored in the Gamma correction data storage circuitry 31, also i.e. each brightness value of gained when each gray scale is presented on the colour liquid crystal display device 1 is used for the common electric voltage V of colour liquid crystal display device 1 each gray scale
ComThe value of feedthrough component (DC component), and gained is fed to the value of the data-signal of data electrode when each gray scale is presented on the colour liquid crystal display device 1, carries out Gamma correction and gray correction.
Gamma correction data storage circuitry 31 comprises that such as ROM, RAM or nonvolatile semiconductor memory refreshing EEPROM etc. constitutes by semiconductor memory, and as shown in Figure 8, have positive frame correction data memory circuit 31a and negative frame correction data memory circuit 31b.Gamma correction data storage circuitry 31 store in advance be all 10 and with the corresponding red correction data D of 8 types of correcting patterns (pattern 1 is to pattern 8) that in each positive frame and negative frame process, reads
RR, green correction data D
GRWith blue correction data D
BR, and present and the 3 bit correction patterns that provided by the outside are selected the corresponding red correction data D of the selected correcting pattern of data DP
RR, green correction data D
GRWith blue correction data D
BRAdopt respectively is 10 and red correction data D that read in each positive frame and each negative frame process
RR, green correction data D
GRWith blue correction data D
BRPrevent to being all 8 red data D
R, green data D
GWith blue data D
BCarry out the reduction that the gamma characteristic linearity takes place afterwards Gamma correction as in the classic method, proofread and correct red data D to convert thereof into
RG, proofread and correct green data D
GGWith the blue data D of correction
BGIn addition, will respectively be 10 and red correction data D that in positive frame and negative frame process, present
RR, green correction data D
GRWith blue correction data D
BRBe used for above-mentioned gray correction.
This correcting pattern of 8 types comprises the correcting pattern that for example is used to make input image signal and variation corresponding to colour liquid crystal display device 1 gamma characteristic of liquid crystal display device variation of ambient temperature to be complementary, the correcting pattern that is used to make the variation of input image signal and colour liquid crystal display device 1 gamma characteristic that changes corresponding to the liquid crystal display device ambient lighting to be complementary, the correcting pattern that colour liquid crystal display device 1 gamma characteristic that is used to make input image signal and changes with the timing signal frequency characteristic variations is complementary, the correcting pattern that colour liquid crystal display device 1 gamma characteristic that is used to make input image signal and changes with the backlight illumination variation is complementary, the discrete correcting pattern that is complementary of the gamma characteristic that is used for making input image signal and colour liquid crystal display device 1 manufacture process to take place, or the like.The red correction data D that is used for each correcting pattern
RR, green correction data D
GRWith blue correction data D
BRGamma characteristic by the colour liquid crystal display device 1 of gained when measuring frequency characteristic when the environment temperature of the liquid crystal display device that is in installment state or ambient lighting, timing signal, backlight illumination variation in advance, perhaps the gamma characteristic that takes place in colour liquid crystal display device 1 manufacture process is discrete, and in order to form by carrying out the value that Gamma correction removes this variation or discrete influence.That is to say that the Gamma correction of present embodiment comprises above-mentioned first Gamma correction and second Gamma correction.
In addition, except being provided with positive frame correction data memory circuit 31a and negative frame correction data memory circuit 31b corresponding to negative frame corresponding to positive frame, the structure of Gamma correction data storage circuitry 31 is identical with Gamma correction data storage circuitry 22 structures shown in Fig. 1, thereby has correspondingly omitted its explanation.
The following describes and be used to calculate above-mentioned red correction data D
RR, green correction data D
GRWith blue correction data D
BRMethod.
(1) at first, identical with the situation of above-mentioned first embodiment, the brightness that measurement can obtain when the data-signal that 0 to 255 gray level is provided is applied to the data electrode of colour liquid crystal display device 1 is to calculate the gamma characteristic (see figure 3).
(2) secondly, measure the common electric voltage V that is used on colour liquid crystal display device 1, showing each shadow tone
Com(be called display gray scale " n on colour liquid crystal display device 1
x" " common electric voltage V
x").Then, for determining common electric voltage V
ComRelevance, as shown in equation (112), obtain the common electric voltage V that is used to show benchmark gray scale (at present embodiment be suitable for showing under the situation of 256 gray levels that the benchmark gray scale for example is 127 gray levels)
Com(be called the common electric voltage V that is used on colour liquid crystal display device 1, showing the benchmark gray level
REF) and each measured common electric voltage V
xDifference as DC voltage V
DCx
V
DCx=V
X-V
REFEquation (112)
Fig. 9 is illustrated under the situation that the benchmark gray scale is 127 gray levels and is used to obtain DC voltage V
DCxAn example of method.In addition, as if Fig. 9 shows common electric voltage V
ComVariation with gray level changes, yet in fact, change the liquid crystal cell changes in capacitance that is caused by gray level and cause that feedthrough component (DC component) changes, and the change of feedthrough component only shows as common electric voltage V
ComVariation.The V of common electric voltage shown in Fig. 9
xBe the voltage that the value that obtained when the flicker that takes place during an ad-hoc location (for example screen center) on colour liquid crystal display device 1 screen in each gray level display is minimized is measured gained.Here, the common electric voltage V of gained when flicker is minimized
xExpression can be eliminated common electric voltage V
ComContained positive component also can be eliminated the value of its negative component in the feedthrough component (DC component).
(3) then, measure as gray level " n
x" be applied to the data-signal V on the data electrode when being presented on the colour liquid crystal display device 1
NxFigure 10 represents an example of data-signal gamma characteristic.
(4) then, carry out Gamma correction by following method, so that the gamma characteristic of the gamma characteristic of colour liquid crystal display device 1 and for example CRT monitor is complementary, even also the normalization brightness of colour liquid crystal display device 1 gamma characteristic equals the normalization brightness of the CRT monitor gamma characteristic of certain gray level.As shown in Figure 3, in the curve " b " of expression CRT monitor gamma characteristic, be " n in gray level
0" time, its normalization brightness is " m
0", and in the curve " a " of expression colour liquid crystal display device 1 gamma characteristic, make its normalization brightness be " m
0" gray level be " n
1".Therefore, as input gray grade " n
0" time, output gray level " n
1".Obtain gray level " n by following method
1".
(a) if to gray level " n
0" gray level of carrying out the Gamma correction gained is integer, the constant same as before gray level " n that is used as of gained gray level then
1".
(b) if to gray level " n
0" gray level of carrying out the Gamma correction gained is not integer, then by will the most closely making normalization brightness become " m in the curve " a " of expression colour liquid crystal display device 1 gamma characteristic
0" two gray level " n of gray level
a" and " n
b" (see figure 4) substitution equation (101), the gained gray level is used as gray level " n
1".
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (101)
" m wherein
a" expression when gray level for the curve " a " of expression colour liquid crystal display device 1 gamma characteristic in " n
a" time normalization brightness that can obtain, " m
b" expression when gray level for the curve " a " of expression colour liquid crystal display device 1 gamma characteristic in " n
b" time normalization brightness that can obtain.In addition, identical among the deriving method of equation (101) and first embodiment.
(c) minimal gray promptly 0 gray level and maximum gray scale promptly do not carry out Gamma correction under the situation of 255 gray levels, these gray scales by former state as gray scale.
Then, as gray level n
1When being presented on the colour liquid crystal display device 1, if adopt the data-signal of in positive frame process, presenting | V
N1+| and the data-signal of in negative frame process, presenting | V
N1-| as the data-signal that is applied to data electrode, derived equation (113) when not carrying out gray correction then:
| V
N1+|=| V
N1-| ... equation (113)
Now, in example shown in Figure 9, adopt DC voltage V
DCxAs working as gray level n
xDirect current when being presented on the colour liquid crystal display device 1, and using DC voltage V
DCxWhen carrying out gray correction, if adopt the data-signal of in positive frame process, presenting | U
N1+| and the data-signal of in negative frame process, presenting | U
N1-| as the data-signal that is applied to colour liquid crystal display device 1 data electrode, then can derive down establish an equation (114) and (115).Figure 11 represents | V
N1+|, | V
N1-|, | U
N1+|, | U
N1-| and common electric voltage V
ComBetween the relation an example:
| U
N1+|=|| V
N1+|-V
DCx| ... equation (114)
| U
N1-|=|| V
N1-|+V
DCx| ... equation (115)
Below, the data-signal that will in positive frame process, present | U
N1+| the gray scale that is presented at when being applied to data electrode on the colour liquid crystal display device 1 is defined as gray level n
R+, and the data-signal that will in negative frame process, present | U
N1-| the gray scale that is presented at when being applied to data electrode on the colour liquid crystal display device 1 is defined as gray level n
rGray level " n
R+" and " n
R-" obtain by following method.
(d) if gray level " n
R+" and " n
R-" all be integer, then the gained gray level is used as gray level by former state.
(e) if gray level " n
R+" and " n
R-" be not integer, then by will with in the data-signal characteristic of colour liquid crystal display device 1 gray scale, can provide data-signal | U
N1+| and | U
N1-| immediate two the gray level " n of gray level
C+" and " n
D+" (under the situation of positive frame) or two gray level " n
C-" and " n
D-" (under the situation of negative frame) (Figure 12 represents the situation of positive frame) substitution equation (116) and (117), the gray level of gained is used as gray level " n
R+" and " n
R-".Figure 12 is the enlarged drawing of part " B " among Figure 10.In Figure 12, straight line " M " is the near linear of curve among Figure 10 " c ":
n
R+=(| U
N1+|+| U
Nd+| n
c-| U
Nc+| n
d)/(| U
Nd+|-| U
Nc+|) ... equation (116)
Wherein " | U
Nc+| " and " | U
Nd+| " be respectively when each the gray level n that provides in the positive frame process is provided in LCD 1 data gray signal characteristic
cAnd n
dThe time data-signal that adopted:
n
R-=(| U
N1-|+| U
Nd-| n
c-| U
Nc-| n
d)/(| U
Nd-|-| U
Nc-|) ... equation (117)
Wherein " | U
Nc-| " and " | U
Nd-| " be respectively when in LCD 1 data gray signal characteristic, being presented at each the gray level n that provides in the frame process is provided
cAnd n
dThe time data-signal that adopted.In addition, equation (116) and (117) can use with first embodiment under the equation that adopts (101) situation identical mode obtain.
(f) minimal gray promptly 0 gray level and maximum gray scale promptly do not carry out Gamma correction under the situation of 255 gray levels, these gray scales by former state as gray scale.
Then, with 8 gray level n of gained
R+And n
R-(decimal system) substitution equation (118) and (119) are calculated as 10 gray level n '
R+And n '
R-(decimal system):
N '
R+=INT (4n
R++ 0.5) ... equation (118)
N '
R-=INT (4n
R-+ 0.5) ... equation (119)
Wherein the integral part of arithmetic operation results in the bracket is only adopted in " INT () " expression.By adopting the aforementioned calculation method, calculate the red correction data D of all correcting patterns
RR, green correction data D
GRWith blue correction data D
BR
Gamma correction circuit 32 has positive frame correcting circuit 32
aWith negative frame correcting circuit 32
bPositive frame correcting circuit 32
aBy being used in the positive frame process from constituting the positive frame correction data memory circuit 31 of Gamma correction data storage circuitry 31
aThat present respectively is 10 red correction data D
RR, green correction data D
GRWith blue correction data D
BR, according to the frame signal S that presents from control circuit 33
F, respectively be 8 red data D to what in positive frame process, present from digital of digital video data memory circuit 21
R, green data D
GWith blue data D
BCarry out Gamma correction so that gray scale to be provided.Similarly, negative frame correcting circuit 32
bBy being used in the negative frame process from constituting the negative frame correction data memory circuit 31 of Gamma correction data storage circuitry 31
bThat present respectively is 10 red correction data D
RR, green correction data D
GRWith blue correction data D
BR, according to the frame signal S that presents from control circuit 33
F, respectively be 8 red data D to what in negative frame process, present from digital of digital video data memory circuit 21
R, green data D
GWith blue data D
BCarry out Gamma correction so that gray scale to be provided.Then, gamma correction circuit 32 first is proofreaied and correct red data D with the Gamma correction result as what be all 10
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1Be fed to FRC circuit 24.The Gamma correction that is undertaken by gamma correction circuit 32 comprises first Gamma correction and second Gamma correction.Positive frame correcting circuit 32
aWith frame signal S
FTiming when presenting is according to 8 the red data D of being all that presents in positive frame process
R, green data D
GWith blue data D
B, and by select with by from positive frame data memory circuit 31
aCorrecting pattern select to present in the corresponding positive frame process of the selected correcting pattern of data DP respectively be 10 red correction data D
RR, green correction data D
GRWith blue correction data D
BR, carry out Gamma correction.Similarly, negative frame correcting circuit 32
bWith frame signal S
FTiming when presenting is according to 8 the red data D of being all that presents in negative frame process
R, green data D
GWith blue data D
B, and by selecting and the conceited frame data memory circuit 31 of origin
bCorrecting pattern select to present in the corresponding negative frame process of the selected correcting pattern of data DP respectively be 10 red correction data D
RR, green correction data D
GRWith blue correction data D
BR, carry out Gamma correction.
Control circuit 33 is made of for example ASIC.Control circuit 33 is according to the horizontal-drive signal S that presents from the outside
H, vertical synchronizing signal S
V, clock CLK etc., produce horizontal scanning pulse P
H, vertical scanning pulse P
V, frame signal S
F, and revertive pulsing POL, and it is fed to gamma correction circuit 32, data electrode driver circuit 26 and scan electrode driving circuit 5.Frame signal S
FBe the signal of display cycle of representing a screen, its polarity is reversed on each screen, can be by with vertical synchronizing signal S
VObtain in two.
The following describes the operation of liquid crystal display device with said structure.At first, when presenting the data " 000 " (scale-of-two) that are used to select pattern shown in Fig. 21 from the outside when selecting data DP, from constituting the positive frame correction data memory circuit 31 of Gamma correction data storage circuitry 31 as correcting pattern
aWith negative frame correction data memory circuit 31
bIn have address A12 to A0 and read corresponding with pattern 1 in positive frame process and that present in the negative frame process respectively is 10 red correction data D successively for the storage area of " 0 " to " 767 " (decimal system)
RR, green correction data D
GRWith blue correction data D
BR, be fed to positive frame correcting circuit 32 then
aWith negative frame correcting circuit 32
bThis pattern 1 makes input imagery and changes the correcting pattern that is complementary by corresponding colour liquid crystal display device 1 gamma characteristic of liquid crystal display device variation of ambient temperature for being used to.
Then, when presenting from the outside by the red data D that is all 8
R, green data D
GWith blue data D
BDuring the digital of digital video data that constitutes, digital of digital video data is read out and is fed to gamma correction circuit 32 after once in being stored in digital of digital video data memory circuit 21.Positive frame correcting circuit 32 in the gamma correction circuit 32
aAccording to frame signal S
F, by being used in the positive frame process from positive frame data memory circuit 31
aThat present respectively is 10 red correction data D
RR, green correction data D
GRWith blue correction data D
BR, respectively be 8 red data D to what in positive frame process, present from digital of digital video data memory circuit 21
R, green data D
GWith blue data D
BCarry out Gamma correction and gray scale is provided.Similarly, the negative frame correcting circuit 32 in the gamma correction circuit 32
bAccording to frame signal S
F, by being used in the negative frame process from negative frame data memory circuit 31
bThat present respectively is 10 red correction data D
RR, green correction data D
GRWith blue correction data D
BR, respectively be 8 red data D to what in negative frame process, present from digital of digital video data memory circuit 21
R, green data D
GWith blue data D
BCarry out Gamma correction and gray scale is provided.Then, gamma correction circuit 32 is fed to FRC circuit 24 as the red data D of first correction that respectively is 10 with the Gamma correction result
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1In addition, identical among the operation of FRC circuit 24, data electrode driver circuit 26 and scan electrode driving circuit 5 and first embodiment, thereby omitted its explanation.
Therefore, according to second embodiment, except that used operation in first embodiment, 32 pairs of gamma correction circuits in positive frame process and present from the outside in the negative frame process be all 8 red data D
R, green data D
GWith blue data D
BCarry out Gamma correction and gray correction and obtain respectively be 10 first proofread and correct red data D
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1In other words, in a second embodiment,, also, be used for the common electric voltage V of colour liquid crystal display device 1 each gray scale promptly according to each brightness value of gained when each gray scale is presented on the colour liquid crystal display device 1 according to the content that is stored in the Gamma correction data storage circuitry 31
ComThe value of feedthrough component (DC component), and the value that is applied to the data-signal of data electrode when showing each gray scale is carried out Gamma correction and gray correction.Therefore, according to the structure of present embodiment, except the effect that obtains at first embodiment, can also realize following effect.
That is to say, traditional gray correction is that the voltage by data-signal in the correction data electrode drive circuit carries out, and therefore, the circuit structure of data electrode driver circuit is done comparatively complicatedly, if use the semiconductor construction data electrode driver circuit, then chip area will become big.In addition, in the SIC (semiconductor integrated circuit) of composition data electrode drive circuit, in the ordinary course of things, a plurality of SIC (semiconductor integrated circuit) must be set with corresponding to a plurality of data electrodes in the colour liquid crystal display device 1, therefore, screen is big more, and the quantity of data electrode driver circuit is big more.In addition, in general, data electrode driver circuit with integral installations such as LCD 1, scan electrode driving circuit, control circuits in LCD (liquid crystal display) module, in addition, if the voltage by data-signal in the correction data electrode drive circuit carries out gray correction, then its structure can not satisfy the requirement in space in the recent saving LCD.On the contrary, according to the structure of present embodiment,,, and can reduce chip area so the structure of data electrode driver circuit can be done comparatively simply because gray correction is undertaken by gamma correction circuit 32.This makes said structure satisfy the requirement of saving space in the LCD recently fully.
The present invention obviously is not limited to the foregoing description, can be changed and retrofit and do not depart from scope and spirit of the present invention.For example, in each the foregoing description, first Gamma correction and second Gamma correction are undertaken by gamma correction circuit 23 and 32, yet, first Gamma correction and the second gamma fine correction can be undertaken by gamma correction circuit 23 and 32, and the rough correction of second gamma can be undertaken by data electrode driver circuit 26.In the case, need the source circuit of gray scale shown in Figure 13 3, and data electrode driver circuit 26 has and the intimate identical structure of the structure of data electrode driver circuit shown in Figure 14 4.
In addition, in each the foregoing description, 8 types correcting pattern is stored in Gamma correction data storage circuitry 22 and 31 in advance, yet the quantity of correcting pattern type can be greater than or less than " 8 ".And, in each the foregoing description, in Gamma correction data storage circuitry 22 and 31, stored red correction data D for each correcting pattern
RR, green correction data D
GRWith blue correction data D
BRYet,, can be with red data D
R, green data D
GWith blue data D
BAs the correction data common storage.This make the memory capacity of Gamma correction data storage circuitry 22 and 31 be reduced and under the constant situation of memory capacity the correcting pattern type be increased.And in each the foregoing description, it in Gamma correction data storage circuitry 22 and 31 respectively is 10 red correction data D that gamma correction circuit 23 and 32 usefulness are stored in advance
RR, green correction data D
GRWith blue correction data D
BRCarry out Gamma correction, yet gamma correction circuit 23 and 32 can carry out Gamma correction by for example arithmetical operation.And, in the above-described embodiments, gray level n
1Obtain to the method shown in (c) by (a) in the top explanation, yet it also can be with other approximation methods calculating.And, in the above-described embodiments, be provided with digital of digital video data memory circuit 21, yet digital of digital video data also can directly be fed to gamma correction circuit 23 and 32 and without digital of digital video data memory circuit 21.In addition, in the above-described embodiments, constitute the red data D of digital of digital video data
R, green data D
GWith blue data D
BFigure place be " 8 ", and by gamma correction circuit 23 and 32 to these data carry out Gamma correction and convert thereof into respectively be 10 first proofread and correct red data D
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1Yet,, red data D
R, green data D
GWith blue data D
BFigure place can be for example " 6 ", and first proofreaies and correct red data D
RG1, first proofread and correct green data D
GG1With the blue data D of first correction
BG1Figure place can be for example " 8 ".
And the present invention not only can be applied to colour liquid crystal display device, also can be applied to monochromatic liquid crystal display.In addition, adopt liquid crystal display device of the present invention can be used for the monitor of personal computer, televisor etc., in the case, this monitor is except that the liquid crystal display device with said structure, also have the analog to digital converter (DAC) that is used for analog video signal is converted to digital video signal, be used for according to the horizontal-drive signal S that presents from the outside
H, vertical synchronizing signal S
VProduce the timing controller of multiple timing signal, and be used for to be matched to the scaling circuit of colour liquid crystal display device resolution from the resolution of the digital of digital video data with different resolution of DAC output.
Claims (30)
1. method that is used to drive LCD comprises:
First step obtains the Gamma correction data, will add in order to the information that repeatedly changes each described digital of digital video data gray scale on it when digital of digital video data is carried out Gamma correction; And
Second step, be used for coming expression ratio by the many a plurality of gray scales of the expressed gray scale number of described digital of digital video data, be used for repeatedly changing the data-signal of each described digital of digital video data gray scale and the data-signal of described generation being fed to successively the data electrode of LCD according to described Gamma correction data thereby produce by carrying out Frame-rate Control.
2. the method that is used to drive LCD as claimed in claim 1, wherein said first step have by by the substep that obtains described Gamma correction data with the most close gray scale that two gray level approximate treatment of required brightness level in the described LCD gamma characteristic are provided.
3. the method that is used to drive LCD as claimed in claim 1, wherein in described first step, read by substep described in the claim 2 for each described digital of digital video data and to obtain and to be stored in described Gamma correction data in the storage medium in advance.
4. the method that is used to drive LCD as claimed in claim 1, wherein in described first step, by adopting first substep, the brightness that measurement obtains when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD is to calculate the gamma characteristic of described LCD, and for described gamma characteristic and required gamma characteristic are matched by adopting one second substep, if to gray level n
0The gray scale of carrying out the Gamma correction acquisition is an integer, and the gray scale that then adopts described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray scale that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness level in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (1) is obtained is as new gray level n
1If, and described gray level n
0Be minimal gray level or maximum gray scale, then adopt described gray level n
0As new gray level n
1And do not carry out described Gamma correction, obtain described Gamma correction data thus:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (1)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain.
5. the method that is used to drive LCD as claimed in claim 1, wherein in described first step, read by first and second substeps described in the claim 4 for each described digital of digital video data and to obtain and to be stored in described Gamma correction data in the storage medium in advance.
6. the method that is used to drive LCD as claimed in claim 1, wherein in described first step, obtain the Gamma correction data, when described digital of digital video data is carried out Gamma correction, will add on it, and it is carried out gray correction so that the voltage of described data-signal described data-signal when shadow tone is provided is in positive frame process or presents and difference in negative frame process in order to the information that repeatedly changes each described digital of digital video data gray scale.
7. the method that is used to drive LCD as claimed in claim 6, wherein said first step have by by the substep that obtains described Gamma correction data with the most close gray level that two gray level approximate treatment of required brightness level in the described LCD gamma characteristic are provided.
8. the method that is used to drive LCD as claimed in claim 6, wherein in described first step, read by substep described in the claim 7 for each described digital of digital video data and to obtain and to be stored in described Gamma correction data in the storage medium in advance.
9. the method that is used to drive LCD as claimed in claim 6, wherein in described first step, by adopting first substep, the brightness of measurement when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD is to calculate the gamma characteristic of described LCD, by adopting second substep, measure as each shadow tone n
xUsed common electric voltage V when being presented on the described LCD
xAnd calculate used common electric voltage V when the gray level display that is used as benchmark is on described LCD
REFWith measured common electric voltage V
xDifference as DC voltage V
DCx,, measure as described shadow tone n by adopting the 3rd substep
xBe fed to the data-signal V of described data electrode when being presented on the described LCD
Nx,, match for making described gamma characteristic and required gamma characteristic, if to gray level n by adopting the 4th substep
0The gray level of carrying out the Gamma correction acquisition is an integer, and the gray scale that then adopts described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray scale that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (2) is obtained is as new gray scale n
1, and under the situation of minimal gray level and maximum gray scale, adopt described gray level n
0As described new gray scale n
1, and by adopting the 5th substep, when by not carrying out the described gray level n of gray correction
1Be applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | V
N1+| and the data-signal of in negative frame process, presenting | V
N1-| with carry out the described gray level n of gray correction
xBe applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | U
N1+| and the data-signal of in negative frame process, presenting | U
N1-| when derived equation (3) and (4), and adopting the data-signal of in positive frame process, presenting | U
N1+| be presented at gray scale on the described LCD when being applied to described data electrode as gray level n
R+And adopt and work as the data-signal of presenting in the negative frame process | U
N1-| be presented at gray level on the described LCD when being applied to described data electrode as gray level n
R-Situation under, if described gray level n
R+With gray level n
R-Be integer and be minimal gray level or maximum gray scale, then adopt described gray level n
R+And n
R-As gray scale, if described gray level n
R+With gray level n
R-Be not integer, then adopt will with data-signal described in the described data-signal characteristic of described LCD gray scale is provided | U
N1+| and | U
N1-| hithermost two the gray level n that in positive frame process, present of gray level
C+And n
D+And two gray level n that in negative frame process, present
C-And n
D-The gray level that substitution equation (5) and (6) are obtained is as gray level n
R+And n
R-Obtain described Gamma correction data thus:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (2)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain:
| U
N1+|=|| V
N1+|-V
DCx| ... equation (3)
| U
N1-|=|| V
N1-|+V
DCx| ... equation (4)
n
R+=(| U
N1+|+| U
Nd+| n
c-| U
Nc+| n
d)/(| U
Nd+|-| U
Nc+|) ... equation (5)
Wherein " | U
Nc+| " and " | U
Nd+| " be respectively when each the described gray level n that provides in the positive frame process is provided in described LCD data gray signal characteristic
cAnd n
dThe time data-signal that adopted:
n
R-=(| U
N1-|+| U
Nd-| n
c-| U
Nc-| n
d)/(| U
Nd-|-| U
Nc-|) ... equation (6)
Wherein " | U
Nc-| " and " | U
Nd-| " be respectively when in described LCD data-signal gamma characteristic, being presented at each the described gray level n that provides in the frame process is provided
cAnd n
dThe time data-signal that adopted.
10. the method that is used to drive LCD as claimed in claim 6, wherein in described first step, read by substep described in the claim 91 to 5 for each digital of digital video data and to obtain and to be stored in described correction data in the storage medium in advance.
11. the method that is used to drive LCD as claimed in claim 1, wherein said Gamma correction can be selected from different Gamma corrections, comprise and be used to reach and the corresponding to Gamma correction of change that causes described LCD gamma characteristic by variation of ambient temperature, be used to reach and the corresponding to Gamma correction of change that causes described LCD gamma characteristic by the ambient lighting variation, be used to reach and the corresponding to Gamma correction of described LCD gamma characteristic that changes with the timing signal frequency characteristic, be used to reach with in order to providing the brightness backlight of light beam to change the corresponding to Gamma correction of described LCD gamma characteristic that changes from described LCD rear portion to it, and be used for reaching the gamma characteristic that takes place with the described LCD manufacture process corresponding to Gamma correction that disperses.
12. the method that is used to drive LCD as claimed in claim 1, wherein said digital of digital video data comprise red data, green data and blue data, and described Gamma correction carries out independently for each described red data, green data and blue data.
13. the method that is used to drive LCD as claimed in claim 12, wherein said Gamma correction comprise to described red data, green data and blue data carry out to provide arbitrarily with first Gamma correction of the corresponding picture reproducing light characteristic of input imagery brightness with so that input image signal and second Gamma correction that red in the described LCD, the green and blue transmissison characteristic that respectively applies voltage is complementary.
14. the method that is used to drive LCD as claimed in claim 1, wherein said information are to be used to select the data of pattern with the described gray scale that repeatedly changes each Gamma correction data.
15. a liquid crystal display device comprises:
LCD;
Gamma correction circuit is used to obtain the Gamma correction data, will add in order to the information that repeatedly changes each described digital of digital video data gray scale on it when digital of digital video data is carried out Gamma correction; And
Data-signal produces circuit, be used for coming expression ratio by the many a plurality of gray scales of the expressed gray scale number of described digital of digital video data, thereby be used for repeatedly changing the data-signal of each described digital of digital video data gray scale and the data-signal of described generation being fed to successively the data electrode of LCD according to described Gamma correction data for producing by carrying out Frame-rate Control.
16. liquid crystal display device as claimed in claim 15, wherein said gamma correction circuit is by obtaining described Gamma correction data by the most close gray scale of two gray level approximate treatment of required brightness level in the described LCD gamma characteristic that provides of usefulness.
17. liquid crystal display device as claimed in claim 15, further comprise a correction data memory circuit, wherein store by by with the most close described Gamma correction data that gray scale obtained that two gray level approximate treatment of required brightness level in the described LCD gamma characteristic are provided, and wherein said gamma correction circuit from described correction data memory circuit read each digital of digital video data described Gamma correction data and will the described feeds of data that reads to described data-signal generation circuit.
18. liquid crystal display device as claimed in claim 15, wherein said gamma correction circuit is by measuring the brightness obtain to calculate the gamma characteristic of described LCD when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD, and for described gamma characteristic and required gamma characteristic are matched, if to gray level n
0The gray scale of carrying out the Gamma correction acquisition is an integer, and the gray scale that then adopts described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray level that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness level in the described LCD gamma characteristic is provided
aAnd n
bThe gray level that substitution equation (7) is obtained is as new gray level n
1If, and described gray level n
0Be minimal gray level or maximum gray scale, then adopt described gray level n
0As new gray level n
1And do not carry out described Gamma correction, obtain described Gamma correction data thus:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (7)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain.
19. liquid crystal display device as claimed in claim 15, further comprise a correction data memory circuit, be used for storing in advance the described Gamma correction data of following acquisition, promptly by measuring brightness when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD to calculate the gamma characteristic of described LCD, for described gamma characteristic and required gamma characteristic are matched, and, if to gray level n
0The gray scale of carrying out the Gamma correction acquisition is an integer, and the gray scale that then adopts described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray level that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness level in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (8) is obtained is as new gray level n
1If, and described gray level n
0Be minimal gray level or maximum gray scale, then adopt described gray level n
0As new gray level n
1And do not carry out described Gamma correction, obtain described Gamma correction data thus, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal and produces circuit from described correction data memory circuit:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (8)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain.
20. liquid crystal display device as claimed in claim 15, wherein said gamma correction circuit obtains the Gamma correction data, when described digital of digital video data is carried out Gamma correction, will add on it, and it is carried out gray correction so that the voltage of described data-signal described data-signal when shadow tone is provided is in positive frame process or presents and difference in negative frame process in order to the information that repeatedly changes each described digital of digital video data gray scale.
21. liquid crystal display device as claimed in claim 20, wherein said gamma correction circuit is by obtaining described Gamma correction data by the most close gray scale of two gray level approximate treatment of required brightness level in the described LCD gamma characteristic that provides of usefulness.
22. liquid crystal display device as claimed in claim 20, further comprise a correction data memory circuit, wherein store by by with the most close described Gamma correction data that gray level obtained that two gray level approximate treatment of required brightness level in the described LCD gamma characteristic are provided, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal from described correction data memory circuit and produces circuit.
23. liquid crystal display device as claimed in claim 20, wherein said gamma correction circuit to calculate the gamma characteristic of described LCD, is worked as each shadow tone n by measuring by the brightness of measurement when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD
xUsed common electric voltage V when being presented on the described LCD
xAnd calculate used common electric voltage V when the gray scale as benchmark is presented on the described LCD
REFWith measured common electric voltage V
xDifference as DC voltage V
DCx, by measuring as described shadow tone n
xBe fed to the data-signal V of described data electrode when being presented on the described LCD
Nx, and for described gamma characteristic and required gamma characteristic are matched, if to gray level n
0Carrying out the gray scale that Gamma correction obtains is integer, and the gray scale by adopting described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray scale that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that the gray level of required brightness in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (9) is obtained is as new gray level n
1, and under the situation of minimal gray level and maximum gray scale, then adopt described gray level n
0As described new gray level n
1, and, when by not carrying out the described gray level n of gray correction
1Be applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | V
N1+| and the data-signal of in negative frame process, presenting | V
N1-| with carry out the described gray level n of gray correction
xBe applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | U
N1+| and the data-signal of in negative frame process, presenting | U
N1-| when derived equation (10) and (11), and adopting the data-signal of in positive frame process, presenting | U
N1+| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R+And adopt and work as the data-signal of presenting in the negative frame process | U
N1-| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R-Situation under, if described gray level n
R+With gray level n
R-Be integer and be minimal gray level or maximum gray scale, then adopt described gray level n
R+And n
R-As gray scale, if described gray level n
R+With gray level n
R-Be not integer, then adopt will with data-signal described in the described data-signal gamma characteristic of described LCD is provided | U
N1+| and | U
N1-| hithermost two the gray level n that in positive frame process, present of gray level
C+And n
D+And two gray level n that in negative frame process, present
C-And n
D-The gray scale that substitution equation (12) and (13) are obtained is as gray level n
R+And n
R-, obtain described Gamma correction data thus:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (9)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain:
| U
N1+|=|| V
N1+|-V
DCx| ... equation (10)
| U
N1-|=|| V
N1-|+V
DCx| ... equation (11)
n
R+=(| U
N1+|+| U
Nd+| n
c-| U
Nc+ | n
d)/(| U
Nd+|-| U
Nc+|) ... equation (12)
Wherein " | U
Nc+| " and " | U
Nd+| " be respectively when each the described gray level n that provides in the positive frame process is provided in described LCD data-signal gamma characteristic
cAnd n
dThe time data-signal that adopted:
n
R-=(| U
N1-|+| U
Nd-| n
c-| U
Nc-| n
d)/(| U
Nd-|-| U
Nc-|) ... equation (13)
Wherein " | U
Nc-| " and " | U
Nd-| " be respectively when in described LCD data-signal gamma characteristic, being presented at each the described gray level n that provides in the frame process is provided
cAnd n
dThe time data-signal that adopted.
24. liquid crystal display device as claimed in claim 20, wherein said gamma correction circuit to calculate the gamma characteristic of described LCD, is worked as each shadow tone n by measuring by the brightness of measurement when the data-signal that provides the minimal gray level to maximum gray scale is fed to data electrode described in the described LCD
xUsed common electric voltage V when being presented on the described LCD
xAnd calculate used common electric voltage V when the gray scale as benchmark is presented on the described LCD
REFWith measured common electric voltage V
xDifference as DC voltage V
DCx, by measuring as described shadow tone n
xBe fed to the data-signal V of described data electrode when being presented on the described LCD
Nx, and for described gamma characteristic and required gamma characteristic are matched, if to gray level n
0Carrying out the gray scale that Gamma correction obtains is integer, and the gray scale by adopting described acquisition is as new gray level n
1If, to gray level n
0Carrying out the gray level that Gamma correction obtains is not integer, then adopts by with the most close two gray level n that required brightness in the described LCD gamma characteristic is provided
aAnd n
bThe gray scale that substitution equation (14) is obtained is as new gray scale n
1, and under the situation of minimal gray level and maximum gray scale, then adopt described gray level n
0As described new gray scale n
1, and, when by not carrying out the described gray level n of gray correction
1Be applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | V
N1+| and the data-signal of in negative frame process, presenting | V
N1-| with carry out the described gray level n of gray correction
xBe applied to the data-signal of in positive frame process, presenting of described data electrode when being presented on the described LCD | U
N1+| and the data-signal of in negative frame process, presenting | U
N1-| when derived equation (15) and (16), and adopting the data-signal of in positive frame process, presenting | U
N1+| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R+And adopt and work as the data-signal of presenting in the negative frame process | U
N1-| the gray scale shown in being presented at when being applied to described data electrode on the LCD is as gray level n
R-Situation under, if described gray level n
R+With gray level n
R-Be integer and be minimal gray level or maximum gray scale, then adopt described gray level n
R+And n
R-As gray scale, if described gray level n
R+With gray level n
R-Be not integer, then adopt will with data-signal described in the described data-signal characteristic of described LCD gray scale is provided | U
N1+| and | U
N1-| hithermost two the gray level n that in positive frame process, present of gray level
C+And n
D+And two gray level n that in negative frame process, present
C-And n
D-The gray scale that substitution equation (17) and (18) are obtained is as gray level n
R+And n
R-, obtain described Gamma correction data thus, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal and produces circuit from described correction data memory circuit:
n
1=(m
0+ m
bN
a-m
aN
b)/(m
b-m
a) ... equation (14)
" m wherein
a" represent that working as gray level is " n in the described colour liquid crystal display device gamma characteristic
a" time brightness that can obtain, " m
b" represent that working as described gray level is " n in the described gamma characteristic of described colour liquid crystal display device
b" time brightness that can obtain:
| U
N1+|=|| V
N1+|-V
DCx| ... equation (15)
| U
N1-|=|| V
N1-|+V
DCx| ... equation (16)
n
R+=(| U
N1+|+| U
Nd+| n
c-| U
Nc+| n
d)/(| U
Nd+|-| U
Nc+|) ... equation (17)
Wherein " | U
Nc+| " and " | U
Nd+| " be respectively when each the described gray level n that provides in the positive frame process is provided in described LCD data-signal gamma characteristic
cAnd n
dThe time data-signal that adopted:
n
R-=(| U
N1-|+| U
Nd-| n
c-| U
Nc-| n
d)/(| U
Nd-|-| U
Nc-|) ... equation (18)
Wherein " | U
Nc-| " and " | U
Nd-| " be respectively when in described LCD data-signal gamma characteristic, being presented at each the described gray level n that provides in the frame process is provided
cAnd n
dThe time data-signal that adopted.
25. liquid crystal display device as claimed in claim 15, further comprise a correction data memory circuit, wherein storage in advance is used to reach and causes described LCD gamma characteristic to change the Gamma correction data of corresponding to Gamma correction by variation of ambient temperature, be used to reach and the Gamma correction data that change the corresponding to Gamma correction of change that causes described LCD gamma characteristic by ambient lighting, be used to reach Gamma correction data with the corresponding to Gamma correction of described LCD gamma characteristic that changes with the timing signal frequency characteristic, be used to reach with in order to provide the brightness backlight of light beam to change the Gamma correction data of the corresponding to Gamma correction of described LCD gamma characteristic that changes from described LCD rear portion to it, and the Gamma correction data that are used for reaching the discrete corresponding to Gamma correction of gamma characteristic that takes place with described LCD manufacture process, and the correcting pattern that will be presented by the outside selects the selected Gamma correction feeds of data of data to described gamma correction circuit, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal from described correction data memory circuit and produces circuit.
26. liquid crystal display device as claimed in claim 17, wherein said correction data memory circuit is stored in advance and is used to reach and cause described LCD gamma characteristic to change the Gamma correction data of corresponding to Gamma correction by variation of ambient temperature, be used to reach and the Gamma correction data that change the corresponding to Gamma correction of change that causes described LCD gamma characteristic by ambient lighting, be used to reach Gamma correction data with the corresponding to Gamma correction of described LCD gamma characteristic that changes with the timing signal frequency characteristic, be used to reach with in order to provide the brightness backlight of light beam to change the Gamma correction data of the corresponding to Gamma correction of described LCD gamma characteristic that changes from described LCD rear portion to it, and the Gamma correction data that are used for reaching the discrete corresponding to Gamma correction of gamma characteristic that takes place with described LCD manufacture process, and the correcting pattern that will be presented by the outside selects the selected Gamma correction feeds of data of data to described gamma correction circuit, and wherein said gamma correction circuit reads the described Gamma correction data that are used for each digital of digital video data and described reading of data is fed to described data-signal from described correction data memory circuit and produces circuit.
27. liquid crystal display device as claimed in claim 15, wherein said digital of digital video data comprise red data, green data and blue data, and described Gamma correction carries out independently for each described red data, green data and blue data.
28. liquid crystal display device as claimed in claim 27, wherein said Gamma correction comprise to described red data, green data and blue data carry out to provide arbitrarily with first Gamma correction of the corresponding picture reproducing light characteristic of input imagery brightness with so that second Gamma correction that red in input image signal and the described LCD, the green and blue transmissison characteristic that respectively applies voltage is complementary.
29. liquid crystal display device as claimed in claim 15, wherein said information are to be used to select pattern repeatedly to change the data of the described gray scale of each Gamma correction data.
30. the monitor with liquid crystal display device comprises:
LCD;
Gamma correction circuit is used to obtain the Gamma correction data, will add in order to the information that repeatedly changes each described digital of digital video data gray scale on it when digital of digital video data is carried out Gamma correction; And
Data-signal produces circuit, be used for coming expression ratio by the many a plurality of gray scales of the expressed gray scale number of described digital of digital video data, be used for repeatedly changing the data-signal of each described digital of digital video data gray scale and the data-signal of described generation being fed to successively the data electrode of LCD according to described Gamma correction data thereby produce by carrying out Frame-rate Control.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021420084A CN100449598C (en) | 2002-08-22 | 2002-08-22 | Liquid crystal display driving method, liquid crystal display and monitor with the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021420084A CN100449598C (en) | 2002-08-22 | 2002-08-22 | Liquid crystal display driving method, liquid crystal display and monitor with the same |
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| Publication Number | Publication Date |
|---|---|
| CN1477614A true CN1477614A (en) | 2004-02-25 |
| CN100449598C CN100449598C (en) | 2009-01-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021420084A Expired - Lifetime CN100449598C (en) | 2002-08-22 | 2002-08-22 | Liquid crystal display driving method, liquid crystal display and monitor with the same |
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| WO2008025252A1 (en) * | 2006-08-22 | 2008-03-06 | Huawei Technologies Co., Ltd. | A method,apparatus for acquiring gamma characteristic parameter in gamma link |
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| CN1967327B (en) * | 2005-11-15 | 2010-12-08 | 三星电子株式会社 | Method and system for adjusting gray-scale level of liquid crystal display device |
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