CN103996391B - Gamma-correction circuit and display device - Google Patents
Gamma-correction circuit and display device Download PDFInfo
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- CN103996391B CN103996391B CN201410157998.6A CN201410157998A CN103996391B CN 103996391 B CN103996391 B CN 103996391B CN 201410157998 A CN201410157998 A CN 201410157998A CN 103996391 B CN103996391 B CN 103996391B
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Abstract
The invention discloses a kind of gamma-correction circuit and display device, relate to technical field of liquid crystal display.The problem that display distortion occurs in the partial liquid crystal display floater that the ideal gamma curve change of the display panels solving same model different batches causes.The gamma-correction circuit that the embodiment of the present invention provides, for display panels is carried out gamma correction, including gamma register and D/A conversion unit, the value in described gamma register gamma electric voltage after described D/A conversion unit is changed is used for forming test gamma curve, described gamma-correction circuit also includes amending unit, during for there is deviation between described test gamma curve and the ideal gamma curve of described display panels, the value of described gamma register is modified, or the reference voltage of logarithmic mode converting unit is modified.
Description
Technical field
The present invention relates to lcd technology, particularly relate to gamma-correction circuit and display device.
Background technology
The mechanism of liquid crystal display is by applying voltage in a pair transparency electrode, controls to be clipped in liquid crystal between electrode
The deflection angle of molecule, thus control light and penetrate from another electrode again from an electrode entrance liquid crystal molecule
Amount, the amount light passed through is the biggest, and brightness is the highest.
For display panels, apply between voltage and the light transmission capacity (GTG) with optimal display result
In non-linear relation, the curve drawn according to this relation is referred to as preferable gamma.Owing to applying voltage
And the nonlinear correspondence relation between GTG, when increasing applying magnitude of voltage equally, light transmission capacity can't wait
Amount ground increases, so, when using the magnitude of voltage corresponding with the brightness linear of input picture as applying Control of Voltage
During display panels output image, the image of output can the brightest or partially secretly (lose compared to the image of input
Very), it is therefore desirable to the voltage being applied on electrode is carried out according to the preferable gamma of display panels
Correction, to avoid exporting the distortion of image, this correction is referred to as gamma(gamma) correction.
Display panels carries out gamma correction need to use gamma correction circuit, including gamma
Depositor and D/A conversion unit.The data of input picture are deposited with gamma after being converted into digital signal and post
In storage, then change through D/A conversion unit, form the gamma voltage corresponding with each GTG, finally export
To the data wire of pixel cell.
During using above-mentioned gamma correction circuit, according to after digital-to-analogue conversion formed gamma voltage with
The curve that corresponding relation between GTG is drawn is referred to as testing gamma.Owing to gamma correction circuit is
Being designed according to preferable gamma, therefore, this test gamma should be with preferable gamma
Curve co-insides.But due to the restriction of production technology, the ideal of the display panels of same model different batches
Gamma can change, if these display panels all use identical gamma correction circuit,
Then test gamma does not changes, and this can make the preferable gamma after testing gamma and changing
Produce relatively large deviation between curve, thus display is lost to cause the partial liquid crystal display floater in same model to occur
Genuine problem.
Summary of the invention
Embodiments of the invention provide a kind of gamma-correction circuit and display device, solve same model different
There is display in the partial liquid crystal display floater that the preferable gamma change of the display panels of batch causes
The problem of distortion.
For reaching above-mentioned purpose, embodiments of the invention adopt the following technical scheme that
A kind of gamma-correction circuit, for carrying out gamma correction to display panels, including gamma register
And D/A conversion unit, the gamma electricity after described D/A conversion unit is changed of the value in described gamma register
Pressure is used for being formed test gamma curve, and described gamma-correction circuit also includes amending unit, for when described survey
When there is deviation between examination gamma curve and the ideal gamma curve of described display panels, to described gamma
The value of depositor is modified, or the reference voltage of logarithmic mode converting unit is modified.
Further, described gamma-correction circuit, also include adder, for by described gamma register
Value be added with the value in described offset register after output to described gamma register, so that described gamma is posted
The value of storage is modified.
Alternatively, the quantity of described gamma register is multiple；Described offset register is for simultaneously at least
The value of two described gamma register is modified.
Preferably, described offset register is by can repeatedly programmed logic device realize.
Alternatively, described D/A conversion unit includes the multiple electricity being connected between voltage input end and earth terminal
Resistance；Described amending unit is the variable resistance being connected between power supply and described voltage input end, for institute
The reference voltage stating D/A conversion unit is modified.
The embodiment of the present invention also provides for a kind of display device, including above-mentioned gamma-correction circuit.
In the gamma-correction circuit of embodiment of the present invention offer and display device, owing to adding amending unit,
When there is deviation between test gamma curve and the ideal gamma curve of display panels, correction can be utilized
The value of gamma register is modified by unit, so that revised gamma is deposited by D/A conversion unit
After the value of device is changed, it is thus achieved that revised gamma electric voltage, or amending unit logarithmic mode can be utilized to change
The reference voltage of unit, so that the gamma electric voltage from D/A conversion unit output obtains correction.According to this
Test gamma curve before test curve ratio is revised after the correction that revised gamma electric voltage is formed is closer to ideal
Gamma curve, so that the deviation between test curve and ideal gamma curve reduces after Xiu Zhenging.Work as liquid crystal
When the brightness of display floater output image is relatively low, can be operated by correction, properly increase the bright of output image
Degree；And when the brightness of display panels output image is higher, it is also possible to operated by correction, reduce defeated
Publish picture the brightness of picture, to reach optimal display effect.And then avoid the generation of display distortion problem.
Accompanying drawing explanation
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to enforcement
In example or description of the prior art, the required accompanying drawing used is briefly described, it should be apparent that, describe below
In accompanying drawing be only some embodiments of the present invention, for those of ordinary skill in the art, do not paying
On the premise of going out creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.
The module map of a kind of gamma-correction circuit that Fig. 1 provides for the embodiment of the present invention；
Test curve and school after the correction that the gamma-correction circuit that Fig. 2 provides for using the embodiment of the present invention produces
The most front test curve and the comparison diagram of ideal gamma curve；
Fig. 3 is corrected for the embodiment of the present invention provides 17 gamma register values in gamma-correction circuit
Example list；
The module map of the Fig. 4 variation of the first gamma-correction circuit for providing based on the embodiment of the present invention；
Fig. 5 shares the gamma school of an offset register for two gamma register that the embodiment of the present invention provides
The module map of positive circuit；
The module map of the first gamma-correction circuit that Fig. 6 provides for the embodiment of the present invention；
The module map of the second gamma-correction circuit that Fig. 7 provides for the embodiment of the present invention.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clearly
Chu, be fully described by, it is clear that described embodiment be only a part of embodiment of the present invention rather than
Whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art are not making creation
Property work on the premise of the every other embodiment that obtained, broadly fall into the scope of protection of the invention.
Embodiments provide a kind of gamma-correction circuit, as depicted in figs. 1 and 2, for liquid crystal
Display floater carries out gamma correction, including gamma register 11 and D/A conversion unit 12, this gamma register
The value in 11 gamma electric voltage after D/A conversion unit 12 is changed is used for forming test gamma curve A, this gal
Horse correcting circuit also includes amending unit 13, for when the ideal of test gamma curve A with display panels
When there is deviation between gamma curve B, the value of gamma register 11 is modified, or logarithmic mode conversion
The reference voltage of unit 12 is modified.
In the gamma-correction circuit that the embodiment of the present invention provides, owing to adding amending unit, when test gamma
When there is deviation between curve and the ideal gamma curve of display panels, amending unit can be utilized gamma
The value of depositor is modified, so that the value of revised gamma register is carried out by D/A conversion unit
After conversion, it is thus achieved that revised gamma electric voltage, or the reference of amending unit logarithmic mode converting unit can be utilized
Voltage, so that the gamma electric voltage from D/A conversion unit output obtains correction.According to this revised gal
After the correction that horse voltage is formed, test curve C is more bent closer to ideal gamma than the test gamma curve A before revising
Line B, so that the deviation between test curve C and ideal gamma curve B reduces after Xiu Zhenging.Work as liquid crystal
Show panel output image brightness relatively low time, can operate by correction, properly increase export image brightness；
And when the brightness of display panels output image is higher, it is also possible to operated by correction, reduce output figure
The brightness of picture, to reach optimal display effect.And then avoid the generation of display distortion problem.
In the gamma-correction circuit that above-described embodiment provides, amending unit 13 can be posted for the skew shown in Fig. 6
Storage 61, for being modified the value of gamma register 11.Owing to using offset register 61 to repair
When just operating, it is only necessary to write the action of depositor, and the size of correction value can be adjusted at any time by reading action,
Therefore can realize revising easy and simple to handle, technique effect intuitively.
Under normal circumstances, the gamma register in gamma-correction circuit has 16～27, is used for regulating display ash
Rank, the size of gamma electric voltage when the numerical value of storage determines display corresponding GTG in gamma register.In Fig. 3
Showing the situation having 17 gamma register in gamma-correction circuit, V0 represents the gamma of 0 grade of GTG of regulation
Depositor, V13 represents the gamma register of 13 grades of GTGs of regulation.
Assume when the value in V0 is 0, after D/A conversion unit 12 is changed, the gamma of 4.3v can be produced
Voltage, after this voltage is applied to the data wire of pixel cell, this pixel cell is shown that 0 grade of GTG.
It is further assumed that the value of gamma register increases by 1, then the gamma electric voltage increase 0.1v produced, therefore, when
When 0 grade of gray-scale intensity of display is inadequate, can arrange the value in V0 is 1, then can produce the gamma electricity of 4.4v
Pressure, thus 0 grade of GTG that display brightness increases on this pixel cell.Realize gamma in this way
In depositor, the numerical value of storage determines the size of gamma electric voltage during display corresponding GTG.
In Fig. 3, the number of offset register has 7, represents with R1～R7, by by gamma register
Value adds the value value as revised gamma register of offset register, thus realizes gamma electric voltage
Adjust.It addition, the value of gamma register represents with 16 systems in Fig. 3.
In the gamma-correction circuit that above-described embodiment provides, it is also possible to include the adder 41 shown in Fig. 4, add
Musical instruments used in a Buddhist or Taoist mass belongs to digital logic device, for addend and augend are performed binary addition operation.In this enforcement
In example, adder 41 is defeated after the value in gamma register 11 being added with the value in offset register 61
Go out to gamma register 11, be modified with the value to gamma register 11.
Certainly, it is achieved the circuit knot value of gamma register 11 being modified by the value of offset register 61
Structure can have a variety of, and the above-mentioned method arranging adder 41 is fairly simple, and needs the device increased less,
Also the chip area that will not make gamma-correction circuit increases too much.It addition, use offset register 61 to gamma
When the value of depositor 11 is modified, the mode being not limited by summation (adder) is revised, and other is right
The computing mode that numerical value is modified, may be incorporated for the present invention as subtracted each other, be multiplied or be divided by etc..
It addition, in the gamma-correction circuit of above-described embodiment offer, the quantity of gamma register 11 is multiple,
Offset register 61 may be used for being modified the value of at least two gamma register 11 simultaneously.Fig. 5 is
One offset register 61 uses two adders 41, and the value to two gamma register is modified respectively
Structural representation.In this way, only can make needing the gamma register 11 that the numerical value revised is identical
By an offset register 61, thus reach to save the purpose using number of devices, and then be possible to prevent gamma
The chip area of correcting circuit increases too much.
In the gamma-correction circuit that above-described embodiment provides, offset register 61 by can repeatedly program (MTP,
Multi Time Program) logical device realization.After the feature of this device is power down, wherein store
Value will not disappear, and can repeatedly revise this value, by MTP logical device by the way of programming
The offset register 61 realized can load, when liquid crystal panel powers on, the value set automatically, right to realize
The automatic correction of gamma register.It addition, the feature that the value of MTP logical device storage can repeatedly revise this can
So that the maker of display panels is according to the difference between different panels, the value of offset register 61 is entered
Row amendment, to be modified the value of gamma electric voltage according to the ideal gamma curve after change.
In the gamma-correction circuit that above-described embodiment provides, D/A conversion unit 12, as it is shown in fig. 7, comprises
The multiple resistance (R1, R2 ..., Rn) being connected between voltage input end VDD and earth terminal GND, also
Including MUX S1, including multiple inputs and an outfan, multiple inputs from different resistance it
Between obtain multiple different voltage, outfan for by multiple input voltage Zhong mono-tunnels export, as one
The gamma electric voltage of GTG.The value of gamma register 11 is used for gating MUX Zhong mono-tunnel, so that it is determined that
The output voltage of MUX.When gamma-correction circuit works, voltage input end VDD meets power supply V, electricity
Source V voltage is the reference voltage of D/A conversion unit 12, and D/A conversion unit 12 is with this reference voltage as base
The accurate gamma electric voltage exporting a kind of GTG.
As it is shown in fig. 7, be in series with variable resistance Rc between power supply V and voltage input end VDD, this is variable
Resistance Rc, as amending unit, has the adjustable characteristic of resistance, electric when the resistance variations of variable resistance Rc
When source V voltage is constant, the voltage of voltage input end VDD can because of on variable resistance Rc the change of dividing potential drop and occur
Change, so that the reference voltage of D/A conversion unit 12 changes, and then makes the gamma electricity of output
Pressure changes, and finally makes the brightness of display panels be adjusted to optimum.It should be noted that number
The reference voltage of mould converting unit 12 can also other modes change, and does not limits at this.
Voltage-light transmittance characteristic curve according to display panels, when voltage changes, middle
The brightness flop of GTG relatively big, and GTG is that 0(is the whitest) and GTG be that 255(is completely black) brightness change
Change less.By by if more slightly turned up for reference voltage, the brightness of middle GTG will be substantially reduced,
And the reduction that the brightness of completely white or black is the most slightly, so that revised test gamma curve C is to ideal
The direction of gamma curve B is moved, and moves closer to ideal gamma curve B.
The embodiment of the present invention also provides for a kind of display device, and including above-mentioned gamma-correction circuit, this display fills
Put that can be that liquid crystal display, LCD TV, DPF, mobile phone or panel computer etc. are any have
The product of display function or parts.
The above, the only detailed description of the invention of the present invention, but protection scope of the present invention is not limited to
This, any those familiar with the art, in the technical scope that the invention discloses, can readily occur in
Change or replacement, all should contain within protection scope of the present invention.Therefore, protection scope of the present invention
Should be as the criterion with described scope of the claims.
Claims (6)
1. a gamma-correction circuit, for display panels is carried out gamma correction, deposits including gamma
Device and D/A conversion unit, the gamma after described D/A conversion unit is changed of the value in described gamma register
Voltage is used for forming test gamma curve, it is characterised in that
Described gamma-correction circuit includes amending unit, for when described test gamma curve and described liquid crystal
Show when there is deviation between the ideal gamma curve of panel, the value of described gamma register is modified, institute
State gamma-correction circuit and also include adder, when the value of described gamma register is repaiied by described amending unit
Timing, described adder exports after the value in described gamma register being added with the value in described amending unit
To described gamma register, it is modified with the value to described gamma register；
Or, exist between described test gamma curve and the ideal gamma curve of described display panels
During deviation, the reference voltage of described D/A conversion unit is modified by described amending unit.
Gamma-correction circuit the most according to claim 1, it is characterised in that when described amending unit pair
When the value of described gamma register is modified, described amending unit is offset register.
Gamma-correction circuit the most according to claim 2, it is characterised in that described gamma register
Quantity is multiple；When the value of described gamma register is modified by described amending unit, described skew is posted
Storage is for being modified the value of gamma register described at least two simultaneously.
4. according to the gamma-correction circuit described in any one of claim 2-3, it is characterised in that described skew
Depositor is by can repeatedly programmed logic device realize.
Gamma-correction circuit the most according to claim 1, it is characterised in that described D/A conversion unit
Including the multiple resistance being connected between voltage input end and earth terminal；
When described amending unit is for being modified the reference voltage of described D/A conversion unit, described in repair
Positive unit is the variable resistance being connected between power supply and described voltage input end.
6. a display device, it is characterised in that include the gamma school as described in claim 1 to 5 is arbitrary
Positive circuit.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410157998.6A CN103996391B (en) | 2014-04-18 | Gamma-correction circuit and display device | |
| US14/448,360 US9886885B2 (en) | 2014-04-18 | 2014-07-31 | Gamma correction circuit and display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410157998.6A CN103996391B (en) | 2014-04-18 | Gamma-correction circuit and display device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103996391A CN103996391A (en) | 2014-08-20 |
| CN103996391B true CN103996391B (en) | 2016-11-30 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0851557A (en) * | 1994-08-08 | 1996-02-20 | Fujitsu General Ltd | Gamma correction circuit |
| CN1573425A (en) * | 2003-06-17 | 2005-02-02 | 精工爱普生株式会社 | Gamma correction circuit, liquid crystal driving circuit, display and power supply circuit |
| CN1697010A (en) * | 2004-05-12 | 2005-11-16 | 索尼株式会社 | Drive circuit for flat display apparatus and flat display apparatus |
| CN1811537A (en) * | 2005-01-25 | 2006-08-02 | 三星电子株式会社 | Gamma correction device, display apparatus including the same, and method of gamma correction therein |
| TWI326443B (en) * | 2004-10-27 | 2010-06-21 | Chunghwa Picture Tubes Ltd | Dynamic gamma correction circuit, method thereof and plane display device |
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0851557A (en) * | 1994-08-08 | 1996-02-20 | Fujitsu General Ltd | Gamma correction circuit |
| CN1573425A (en) * | 2003-06-17 | 2005-02-02 | 精工爱普生株式会社 | Gamma correction circuit, liquid crystal driving circuit, display and power supply circuit |
| CN1697010A (en) * | 2004-05-12 | 2005-11-16 | 索尼株式会社 | Drive circuit for flat display apparatus and flat display apparatus |
| TWI326443B (en) * | 2004-10-27 | 2010-06-21 | Chunghwa Picture Tubes Ltd | Dynamic gamma correction circuit, method thereof and plane display device |
| CN1811537A (en) * | 2005-01-25 | 2006-08-02 | 三星电子株式会社 | Gamma correction device, display apparatus including the same, and method of gamma correction therein |
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Granted publication date: 20161130 |