CN101471055A

CN101471055A - Transient control drive method and circuit, and image display system thereof

Info

Publication number: CN101471055A
Application number: CNA2008101905138A
Authority: CN
Inventors: 爱德华兹·马丁
Original assignee: Toppoly Optoelectronics Corp
Current assignee: Chi Mei Optoelectronics Corp
Priority date: 2007-12-25
Filing date: 2008-12-25
Publication date: 2009-07-01
Anticipated expiration: 2028-12-25
Also published as: CN101471055B

Abstract

The present invention relates to a transient control drive method, for driving a liquid crystal capacitor of a pixel circuit from a first voltage level to a second voltage level, comprises: driving the liquid crystal capacitor from the first voltage level to an intermediate voltage level; and driving the liquid crystal capacitor from the intermediate voltage level to the second voltage level. The present invention further provides a transient control drive circuit and an image display system thereof.

Description

The driving method of transient state control, circuit with and image display system

Technical field

The present invention is about a kind of image display system, especially about a kind of driving method of transient state control, circuit with and image display system.

Background technology

At present known after the pixel addressing, the change of liquid crystal (LC) element on electric capacity can influence the switching time of pixel in the image display system (particularly active matrix liquid crystal display).

To be generally white TN type LCD is example, and when switching between different luminance states, the electric capacity of pixel also can change, and wherein liquid crystal cell has low relatively electric capacity when bright attitude, then has high relatively electric capacity when it is in dark attitude.Generally speaking, the reaction time of liquid crystal cell (promptly switching to the required time of another luminance state from a luminance state) is longer than the duration of charging of pixel, so after the pixel addressing, electric capacity can change.During each of pixel addressing (during promptly keeping), be to keep pixel voltage by the pixel capacitance amount, wherein the pixel capacitance amount generally is made up of the electric capacity of a liquid crystal cell and a storage unit.Any numerical value change of the pixel capacitance amount that causes because of the change of liquid crystal layer electric capacity during keeping can make pixel voltage change.

Figure 12 is the circuit diagram that shows a known pixels 60 in the active matrix liquid crystal display.Pixel 60 has a reservior capacitor 61 and in order to a liquid crystal (LC) capacitor 62 of the brightness of display pixel 60, and wherein reservior capacitor 61 and the electric capacity of LC capacitor 62 promptly constitute the pixel capacitance amount of pixel 60.The driving voltage source V of delegation ₁Be supplied to pixel 60, and the delivery gray level information is with the brightness of decision pixel 60.By using a control signal S ₁With conducting one switch 63, make a side of reservior capacitor 61 and LC capacitor 62 charge to voltage source V ₁Output voltage position standard, can be to pixel 60 addressing, wherein V _LCRepresent the voltage level of LC capacitor 62 1 sides, it is the driving voltage that is supplied to LC capacitor 62.(promptly and V simultaneously, to the opposite side of LC capacitor 62 _LCThe side that side is relative) supply-voltage source V _COM, and to the opposite side of reservior capacitor 61 (promptly and V _LCThe side that side is relative) supply-voltage source V _CAP, V wherein _COMRepresent the common voltage of LC capacitor 62.

When described pixel 60 is switched to dark attitude by brighter attitude, be supplied to the driving voltage V of LC capacitor 62 _LCSize by being transformed into high value, as shown in figure 13 than low value.Figure 13 is the addressing that shows pixel shown in Figure 12, wherein V _1PRepresentative is when the voltage source V during to pixel 60 addressing with a positive voltage ₁Output voltage position standard, and V _1NRepresentative is when the voltage source V during to pixel 60 addressing with a negative voltage ₁Output voltage position standard.Driving voltage V _LCValue is with respect to common voltage V _COMAnd increase with to 62 chargings of LC capacitor, and pixel 60 is switched to dark attitude.

Utilizing the higher accurate V in driving voltage position _1PDuring after pixel 60 addressing first are kept, LC capacitor 62 will begin switching state and its electric capacity also can increase, and this makes the value of electric capacity when pixel 60 addressing of LC capacitor 62 increase, and thereby reduce the value of the voltage drop at LC capacitor 62 two ends.

Please refer to following equation:

V_{DROP} = (V_{1} - V_{COM}) \frac{C_{S} + C_{LC} *}{C_{S} + C_{LC}},

V wherein _DROPThe value of representing LC capacitor 62 both end voltage to fall, C _SRepresent the electric capacity of reservior capacitor 61, C _LCRepresent the instant value of the electric capacity of LC capacitor 62, and C _LC ^*Represent the electric capacity of LC capacitor 62 when end switch 63 is closed between charge period.

After pixel 60 chargings, V _DROPChange, this changes the brightness variation that obstruction is desired, so pixel 60 is only partly shifted to new luminance state during first addressing.When pixel 60 addressing next time, it is accurate that the pixel capacitance amount is charged to the position of corresponding required new luminance state once again.Generally speaking, during each pixel 60 addressing, voltage source V ₁Polarity can be oppositely, and this reverse voltage is with respect to voltage level V _1PVoltage level V _1NRepresent, as shown in figure 13.Second keep during, when the luminance state of pixel 60 near default steady-state value the time, the electric capacity of LC capacitor will increase once again, although the amplitude of this variation will be less than before.This can cause V again _DROPValue reduce.

At the voltage level V that changes LC capacitor 62 _LCAfter each time continuously during the addressing, pixel intensity will be more near its steady-state value, as shown in figure 14.Figure 14 is the accurate V in display voltage position _LCAnd the graph of a relation of pixel intensity.Even the reaction time of LC capacitor 62 is short during than an addressing, for pixel 60, after once changing, its need through during a plurality of addressing with near its new stable state brightness.When switching to brighter attitude by dark attitude, pixel also produces identical effect; For 60 pixels are switched to brighter attitude, must make pixel 60 addressing with a lower voltage.In first keep during, after to pixel supply low voltage, liquid crystal will begin to switch and its electric capacity will reduce.As electric capacity C _LCDuring minimizing, the magnitude of voltage V of pixel 60 _DROPIncrease, and this can hinder the institute of pixel to desire the brightness variation.

In sum, when under the active-matrix drive condition, adopting known drive scheme, because the liquid crystal capacitance amount depends on the effect of voltage, even thereby the reaction time of liquid crystal is short during than addressing, described pixel is still obviously prolonged by the required time that one first luminance state switches to one second luminance state.

Summary of the invention

The object of the present invention is to provide transient state (transient) the controlling and driving method and the circuit of the pixel of a kind of image display system (particularly LC display), to improve the switching behavior of pixel.

Another purpose of the present invention is to improve the power consumption of pixel, and it passes through the increase of restriction row driving voltage and reduce required capable driving voltage capable.

For reaching above-mentioned purpose, the invention provides a kind of transient state controlling and driving method, be urged to one second voltage level in order to a liquid crystal capacitor from one first voltage level with an image element circuit.The method may further comprise the steps: liquid crystal capacitor is urged to a medium voltage position standard from first voltage level; And liquid crystal capacitor is urged to second voltage level by medium voltage position standard.

For reaching above-mentioned purpose, the present invention further provides a transient state control Driver Circuit, be urged to one second voltage level in order to a liquid crystal capacitor by one first voltage level with an image element circuit.Described circuit comprises: liquid crystal capacitor; Be electrically coupled to a reservior capacitor of liquid crystal capacitor; And a switchgear, in order to the control reservior capacitor so that it is urged to a tertiary voltage position standard, control liquid crystal capacitor so that it is urged to a medium voltage position standard by first voltage level and the control liquid crystal capacitor makes it via sharing with the electric charge of reservior capacitor and being urged to second voltage level from medium voltage position standard.

For reaching above-mentioned purpose, the present invention further provides a kind of image display system, described image display system comprises: a plurality of image element circuits, each image element circuit have a transient state control Driver Circuit with a liquid crystal capacitor of an image element circuit by one first driven to, second voltage, wherein said transient state control Driver Circuit comprises: liquid crystal capacitor; Be electrically coupled to the reservior capacitor of liquid crystal capacitor; And a switchgear, it and makes liquid crystal capacitor be urged to second voltage by medium voltage by reservior capacitor by first driven to a medium voltage so that it is urged to second voltage, control liquid crystal capacitor in order to the control reservior capacitor; One first voltage source is in order to be urged to reservior capacitor tertiary voltage position standard; And one second voltage source, in order to liquid crystal capacitor is urged to medium voltage position standard by first voltage level.

According to the above, the present invention adopts a kind of drive scheme that drives liquid crystal cell between two position standards, wherein work as liquid crystal cell and be driven to first on time, the voltage drop meeting at liquid crystal cell two ends is reset, and be driven to second on time when it, the voltage drop meeting at liquid crystal cell two ends increases, to reach the luminance state of expection.

Delay phenomenon when the drive scheme that the present invention proposes can be eliminated pixel and switches, it is to go in the value of liquid crystal capacitance amount by pixel voltage being had nothing to do when the pixel addressing; The present invention also revises the switching behavior of pixel with a control mode in response to the change of display operation situation, to improve the performance of display when showing switching or mobile image.In addition, after the control in conjunction with drive scheme and common electrode voltage, the present invention has also reduced the power consumption of display.

Description of drawings

By accompanying drawing and detailed description, will understand purpose, spirit and the advantage of preferred embodiment of the present invention easily, wherein:

Fig. 1 is the circuit diagram that shows the pixel in the present invention's one specific embodiment.

Fig. 2 is the addressing oscillogram of the pixel shown in the displayed map 1.

Fig. 3 is overshoot (overshoot) oscillogram of the pixel shown in the displayed map 1.

Fig. 4 is following (undershoot) oscillogram of dashing of the pixel shown in the displayed map 1.

Fig. 5 is the pixel intensity oscillogram of the pixel shown in the displayed map 1.

Fig. 6 is the circuit diagram that shows the pixel in another specific embodiment of the present invention.

Fig. 7 is the addressing oscillogram that shows pixel shown in Figure 6.

Fig. 8 is the circuit diagram that shows the pixel in the another specific embodiment of the present invention.

Fig. 9 is the voltage level that shows the capable driving voltage of pixel shown in Figure 6.

Figure 10 is the oscillogram that shows switching behavior in the pixel shown in Figure 6.

Figure 11 is the voltage level that shows row driving voltage in the pixel with three kinds of common electrode voltage position standards.

Figure 12 is the circuit diagram that shows a known pixels of an active-matrix LC display.

Figure 13 is the addressing oscillogram that shows pixel shown in Figure 12.

Figure 14 is the pixel intensity oscillogram that shows pixel shown in Figure 12.

Drawing reference numeral

10,20,30,60 pixels

11,21,31,61 reservior capacitors

12,22,32,62 liquid crystal capacitors

13～15 switches

23～25 switches

33～35 switches

63 switches

Embodiment

The present invention fully describes by the appended accompanying drawing that contains preferred embodiment of the present invention, but should be appreciated that the those skilled in the art can revise invention described herein, obtained effect of the present invention simultaneously before this describes.Therefore, need to understand following description to the those skilled in the art and Yan Weiyi discloses widely, and its content does not lie in restriction the present invention.

The present invention is about a kind of image display system with a plurality of pixels.The present invention proposes a drive scheme, improving the switching behavior of pixel, and does not have the expenditure and the complicated signal Processing solution of extra cost.

Consult Fig. 1, it shows a pixel 10 of one specific embodiment according to the present invention.Pixel 10 has a reservior capacitor 11, a liquid crystal (LC) capacitor 12 and three

switches

13,14,15, and

switch

13,14,15 is represented aggressive device (as thin film transistor (TFT)), and it is in order to addressing pixel 10.

By switch 13 supplies one voltage source V ₁With to reservior capacitor 11 chargings, supply another voltage source V by switch 15 ₂With to LC capacitor 12 charging, and switch 14 is to be used to connect the usefulness that reservior capacitor 11 and LC capacitor 12 are shared for electric charge, and wherein switch the 13, the 15th, by control signal S ₁Control, and switch 14 is by control signal S ₂Control.Wherein, V _SRepresent the voltage level of the opposite side of reservior capacitor 11, and V _LCRepresent the voltage level of the opposite side of LC capacitor 12.In addition, voltage source V _COMBe to be supplied to respect to LC capacitor 12 to have V _LCThe opposite side of a side, and voltage source V _CAPBe to be supplied to respect to reservior capacitor 11 to have V _SThe opposite side of a side.

Consult Fig. 2, it shows the addressing oscillogram of pixel 10 shown in Figure 1, wherein V _1PRepresentative row driving voltage source V ₁High voltage level, V _1NRepresentative row driving voltage source V ₁Low-voltage position standard, V _PRepresent the positive pixel voltage position standard under stable state driving situation, and V _NRepresent the negative pixel voltage level under stable state driving situation.In this specific embodiment, voltage source V ₂The voltage level of output is to be equal to voltage source V _COMOutput voltage position standard.

As control signal S ₂Be in low state, at first open switch 14 to separate two

capacitors

11,12, then control signal S ₁Transfer high state to, so voltage level V _SBe charged to voltage source V ₁Output voltage position standard, and voltage level V _LCBe charged to voltage source V ₂Output voltage position standard.When

capacitor

11,12 is finished charging, control signal S ₁Be returned to low state, and two

capacitors

11,12 and two voltage source V ₁, V ₂Isolate, then S ₂Return into high state, and

capacitor

11,12 links together and shares to carry out electric charge.

After the generation electric charge was shared, the voltage at LC capacitor 12 two ends can be represented by following equation:

V_{DROP} = (V_{1} - V_{COM}) \frac{C_{S}}{C_{S} + C_{LC}}

Wherein, C _SRepresent the value of the electric capacity of reservior capacitor 11, C _LCRepresent the moment or the present value of the electric capacity of LC capacitor 12, and V _DROP Represent LC capacitor 12 and reservior capacitor 11 to carry out after electric charge shares, the magnitude of voltage at LC capacitor 12 two ends, also therefore represent electric charge to share generation after, the voltage at LC capacitor 12 two ends.

When pixel 10 addressing, magnitude of voltage V _DROPBe not to decide according to the electric capacity of LC capacitor 12, this is because when pixel 10 addressing, and LC capacitor 12 can discharge, so after electric charge is shared, and the electric charge of pixel 10 is not the value of the electric capacity of LC capacitor 12 during according to the pixel addressing and deciding.If reaction time of LC capacitor 12 is short during than addressing, then pixel 10 reaches correct luminance state in will be during an addressing of the variation of the driving position standard of being supplied.

Therefore, when pixel 10 addressing, electric charge is shared the magnitude of voltage V after carrying out _DROPBe not to decide, but depend on the instant value C of the electric capacity of LC capacitor 12 according to the electric capacity of LC capacitor 12 _LC, have good effect its switching time to LC capacitor 12.

Under steady state conditions,, act on the accurate V in driving voltage position of LC capacitor 12 when pixel 10 reaches the brightness of expection stable state _LCBe stable state electric capacity C according to corresponding LC capacitor 12 _LCSSAnd decide; Yet, before pixel 10 reaches steady state conditions, act on voltage level on the LC capacitor 12 and be instant value C with the electric capacity of LC capacitor 12 _LCDifferent.

When pixel 10 is driven to than the low-light level state by the higher brightness state, instant value C _LCAt the beginning will be than stable state electric capacity C _LCSSLow, and the magnitude of voltage V of LC capacitor 12 _DROPInstant value will be than steady-state value height.Magnitude of voltage V _DROPIncrease help to drive LC capacitor 12 and go to the low-light level state quickly, therefore reduce the switching time of pixel 10.

And when pixel 10 when being driven to the higher brightness state than the low-light level state, initial instant value C _LCWill be than stable state electric capacity C _LCSSHeight, and the magnitude of voltage V of LC capacitor 12 _DROPWill be lower than steady-state value.Magnitude of voltage V _DROPMinimizing help to drive LC capacitor 12 and go to the high brightness state quickly, therefore reduce the switching time of pixel 10.Therefore, the magnitude of voltage V of LC capacitor 12 _DROPTend to by voltage level V _LCSurpass or do not surpass its stable state, as shown in Figures 3 and 4.

Fig. 3 shows that the voltage drop across LC capacitor 12 two ends surpasses steady-state value, wherein pixel 10 by a correspondence than the accurate V in low driving voltage position _LCThe higher brightness state switch to one and have the accurate V in higher drive position _LCThan the low-light level state.After pixel 10 addressing, C _LCInstant value is lower than its steady-state value at first, voltage level V _LCInitial its steady-state value V that surpasses _P, and magnitude of voltage V _DROPSurpass its steady-state value.As 12 couples of voltage level V of LC capacitor _LCIncrease react and electric capacity C _LCDuring increase, across the magnitude of voltage V at LC capacitor 12 two ends _DROPReduce and be tending towards steady-state value.

Fig. 4 shows that the voltage drop across LC capacitor 12 two ends does not surpass steady-state value, and wherein pixel 10 is by the accurate V in a corresponding higher drive position _LCSwitch to one than the low-light level state and have than the accurate V in low driving voltage position _LCThe higher brightness state.After pixel 10 addressing, C _LCInstant value exceeds its steady-state value at first, voltage level V _LCDo not surpass its steady-state value V at first _P, and magnitude of voltage V _DROPDo not surpass its steady-state value.As 12 couples of voltage level V of LC capacitor _LCMinimizing react and electric capacity C _LCDuring minimizing, across the magnitude of voltage V at LC capacitor 12 two ends _DROPIncrease and be tending towards steady-state value.

By above-mentioned specific embodiment as can be known, voltage source V ₂Be be set as near or be equal to the voltage level of a side that is supplied to LC capacitor 12, generally speaking described voltage level is common electrode voltage source V _COMOutput voltage position standard, so when pixel 10 addressing, the electric capacity C of LC capacitor 12 _LCMost or fully discharged.Therefore, when pixel 10 addressing, can make magnitude of voltage V across LC capacitor 12 two ends _DROPNot influenced by the electric capacity of LC capacitor 12.In addition, on LC capacitor 12, produce voltage level V _LCMode, mean when LC capacitor 12 switches voltage level V _LCWill above or surpass its steady-state value, this will help to increase the LC capacitor with the speed of change state.

In the present invention's one specific embodiment, voltage source V ₂No longer be subjected to must near or equal voltage source V _COMAccurate this condition in output voltage position limit, and across the voltage source V of LC capacitor 12 two ends generation _DROPThe equation correction as follows:

V_{DROP} = (V_{1} - V_{COM}) \frac{C_{S}}{C_{S} + C_{LC}} + (V_{2} - V_{COM}) \frac{C_{LC} *}{C_{S} + C_{LC}}

Wherein, C _LC ^*The electric capacity of LC capacitor 12 during the represent pixel addressing, so voltage level V _LCBe charged to voltage source V ₂Output voltage position standard.

Voltage source V _DROPEquational first term causes aforementioned switching effect, wherein if 12 pairs of pixels 10 of LC capacitor have the sufficient reaction time, can reach expecting state in then during an addressing.Equational second is passed through to change voltage source V ₂The accurate voltage source V of revising in output voltage position _DROP

If voltage source V ₂With V _COMBoth output voltage position standards are subtracted each other (V ₂-V _COM) the result have and voltage source V ₁With V _COMBoth output voltage position standards are subtracted each other (V ₁-V _COM) the polarity that comes to the same thing, pixel 10 is with overdamping reaction switching state so, and pixel 10 need through during two or several addressing to move to a new state.If (V ₂-V _COM) have and (V ₁-V _COM) opposite polarity, pixel 10 is with underdamping reaction switching state so, and the pixel 10 initial expecting states that surpass, and then through during two or several addressing with near stable situation.

Fig. 5 is presented under the different output voltages position standard of voltage source V 2, and one than the change over condition between a low-light level state and the higher brightness state.If (V ₂-V _COM) have and (V ₁-V _COM) identical polarity, pixel 10 is with overdamping reaction switching state so, and pixel 10 need through during two or several addressing to move to new state.If (V ₂-V _COM) have and (V ₁-V _COM) opposite polarity, pixel 10 is with underdamping reaction switching state so, and the pixel 10 initial expecting states that surpass, and then through during two or several addressing with near stable situation.

If reaction time of LC capacitor 12 is long during than the addressing of pixel 10, then the reaction time of LC capacitor 12 can tend to the judgement of leading pixel 10 whole switching behaviors.Yet, select voltage source V ₂An output voltage position standard that can produce underdamping reaction help to reduce switching time of LC capacitor 12.

As indicated above, (V ₂-V _COM) with respect to (V ₁-V _COM) the characteristic of polarity decision switching behavior.(V ₂-V _COM) the underdamping or the overdamping degree of switching characteristic of size decision pixel 10.(V ₂-V _COM) size can be preset to a particular value that causes expecting transient behavior.Perhaps, (V ₂-V _COM) big I according to the operational circumstances of LCD system, as temperature or picture material, and change.Can be with voltage source V ₂Outputting level be set as the GTG that is driven to according to pixel 10 and decide, be with voltage source V ₁With V ₂Be to decide according to image information, this switching behavior that can reduce pixel 10 is subjected to the influence degree of the initial and final GTG of brightness transition.

As indicated above, when pixel 10 when the initial stage is recharged during addressing, the present invention can significantly reduce or eliminate pixel intensity is subjected to pixel 10 latter stage during an addressing state institute effect.This means that after then the driving voltage size changed, pixel 10 reached correct luminance state in will be during an addressing if reaction time of LC capacitor 12 is short during than addressing.The voltage source V of data representing image ₁Not directly to 12 chargings of LC capacitor.When pixel 10 addressing, across the voltage V at LC capacitor 12 two ends _DROPBe be set as near or equal 0, and reservior capacitor 11 is charged to voltage source V ₁Outputting level, a brightness value of described outputting level data representing image.Then, by redistributing the electric charge between reservior capacitor 11 and the LC capacitor 12, view data is transferred into LC capacitor 12.

The voltage source V of pixel 10 ₁And 10 couples of voltage level V of pixel _LCThe final luminance state of any change after reacting not influenced by the electric capacity of LC capacitor 12.In the specific embodiment of the invention, magnitude of voltage V _DROPThe time of being discharged is generally speaking short than the reaction time of LC capacitor 12, so the brightness of section time interior pixel 10 or luminance state change minimum or almost do not change.

Fig. 6 shows another control circuit of a pixel 20 in the present invention's one specific embodiment.Pixel 20 comprises a reservior capacitor 21, one LC capacitors 22, and two switches 23 and 24, wherein voltage source V ₁With V ₂As a voltage source V shown in Figure 7 _CThe row that is provided to pixel 20 according to sequential connects.Voltage V across LC capacitor 22 two ends _DROPIdentical with the equation of embodiment shown in Figure 1.

Fig. 8 shows a control circuit of a pixel 30 in another specific embodiment of the present invention.Pixel 30 comprises a reservior capacitor 31, one LC capacitors 32, and three

switches

33,34 and 35, wherein by changing the voltage level V of storage capacitors 31 1 sides _S, view data is connected to LC capacitor 32.As voltage level V _SBy voltage source V ₁Output voltage position standard be switched to voltage source V _CAPThe output voltage position punctual, can carry out electric charge between reservior capacitor 31 and the LC capacitor 32 and redistribute.Magnitude of voltage V across LC capacitor 32 two ends _DROPCan present by following equation:

V_{DROP} = (V_{CAP} - V_{1}) \frac{C_{S}}{C_{S} + C_{LC}} + (V_{2} - V_{COM}) \frac{C_{S} + C_{LC} *}{C_{S} + C_{LC}}

Wherein, if voltage source V ₂With V _CAPOutput voltage position standard equal voltage source V _COMOutput voltage position standard, then the equation of this equation and Fig. 1 pixel 10 is except the first term opposite in sign, all the other are identical.

As indicated above, in some specific embodiment, when the pixel addressing, can not discharged across the magnitude of voltage at LC capacitor two ends, but pixel is charged to one and be provided to synchronous (between the polarity alternately it) voltage of the alter polarity of view data of pixel by reservior capacitor.This voltage can have and the identical polarity of voltage that is supplied to the LC capacitor by the pixel storage capacitor device, and pixel will have an overdamping switching response this moment; Perhaps, described voltage can have and provide via reservior capacitor to the opposite polarity of the signal of liquid crystal, and pixel will have a underdamping switching response this moment.The present invention further proposes, and the voltage that is provided to the LC capacitor during addressing can be modified with the switching behavior of controlling pixel and the performance that improves image display system.Row driving voltage position will definitely change with the expection luminance bit of pixel is accurate, is also to comprise view data with the voltage source that is supplied to the LC capacitor.

Because the electric charge design of sharing, the present invention will need than the higher capable driving voltage position standard of known pixels control circuit to set a luminance state.With pixel shown in Figure 6 20 is example, wherein is supplied to the voltage level V of LC capacitor 22 _LCThan capable driving voltage source V ₁Output voltage position standard low, so voltage source V of pixel 20 ₁Required output voltage position standard than known pixels height.

In the present invention's one specific embodiment, row driving voltage source V ₁Output voltage position standard have certain scope to avoid consuming more electric power.Fig. 9 shows the capable driving voltage position standard of pixel shown in Figure 6 20, wherein voltage level V _MAX1With V _MIN1Representative voltage source V ₁The original scope of output voltage position standard, and V _MAX2With V _MIN2Representative voltage source V ₁The scope of output voltage position standard after dwindling.

In specific embodiment, if utilize voltage source V ₂Provide pixel 20 more multivoltage reach the highest driving voltage position standard, then voltage source V by this ₁The voltage range of output voltage position standard can be defined.Work as voltage source V ₂Output voltage position standard be not limited to voltage source V in the whole image data scope _COMThe output voltage position punctual, voltage source V ₁The scope of output voltage position standard can be contracted to voltage level V _MAX2With V _MIN2

During just driving, when view data increases, voltage source V ₁Output voltage position standard with respect to voltage source V _COMThe corrigendum that becomes of output voltage position standard, reach voltage level V up to it in image data value/threshold value (Threshold) _MAX2Till.For the image data value that surpasses threshold value, voltage source V ₁The output voltage position will definitely maintain voltage level V _MAX2, and voltage source V ₂Output voltage position criterion be set the corrigendum to provide the LC capacitor more than 22 its needed driving voltages.

During negative the driving, when image data value increases, voltage source V ₁Output voltage position standard with respect to voltage source V _COMOutput voltage position standard become more negative, reach voltage level V up to it in image data value/threshold value _MIN2Till.For the image data value that surpasses threshold value, voltage source V ₁The output voltage position will definitely maintain voltage level V _MIN2, and voltage source V ₂Output voltage position criterion be set more negatively to provide the LC capacitor more than 22 its needed driving voltages.

Work as voltage source V ₂Output voltage position standard no longer maintain the voltage source V that exceeds threshold value _COMOutput voltage position standard, the switching behavior of pixel 20 will be weakened up to voltage source V ₂Output voltage position standard equal voltage source V ₁Output voltage position standard till, this moment, its switching behavior will be identical with the switching behavior of known drive.By making voltage source V in this way ₂Decide according to view data, might accomplish to exchange more preferably switching effect for the higher display power consumption increase that capable driving voltage was caused.

In addition, a special image data value is arranged, i.e. threshold value, when this threshold value, voltage source V ₁Output voltage position standard stop to change and voltage source V ₂Output voltage position standard begin to change.In fact, be preferably in voltage source V ₁Output voltage position standard reach the accurate V in maximum voltage position _MAX2Begin to increase voltage source V before ₂Output voltage position standard, voltage source V thus ₁With V ₂Output voltage position standard all in an image data value scope, change, this help avoid any with from controlling voltage source V ₁The view data of output voltage position standard switch to control voltage source V ₂The image error (imageartifacts) that is associated of the view data of output voltage position standard.Desire to reach a specific LC driving voltage position standard and need voltage source V ₁With V ₂Output voltage position standard, therefore can utilize graph of a relation shown in Figure 1 to predict a specific stable state pixel intensity.

In the present invention's one specific embodiment since in conjunction with the electric charge driving method with common electrode drive side thereby reduce to voltage source V ₁The requirement of output voltage position standard.In the common electrode driving method, a differential voltage (reseting voltage) is provided to LC capacitor 22, therefore works as V ₁Polarity be timing, V _COMPolarity will be negative; Work as V ₁Polarity when negative, V _COMPolarity just will be.The oscillogram of the common electrode voltage of Figure 10 displayed map 6 pixels 20 and row driving voltage, wherein V _CPV during the negative driving of representative _COMPositive voltage position standard, V _CNV during representative is just driving _COMNegative, and V _CMRepresent V _COMThe average voltage level.In this specific embodiment, as middle voltage level V _CMBe provided to common electrode voltage source V _COMThe time, preferably reset LC capacitor 22.

Reset voltage be provided to LC capacitor 22 during, common electrode voltage source V _COMBe switched to its average V _CMAnd this identical voltage also is provided to column electrode.Utilize the method, will can not increase with supply common electrode voltage to the capable voltage range that the demand of the row of display is associated.

In addition, voltage source V shown in Figure 9 ₁Scope and voltage source V _COMChange can be combined, as shown in figure 11, voltage source V wherein ₂Output voltage position standard be not set as and voltage source V _COMThe output voltage position accurate identical obtaining lower data value, but be set as one between voltage source V ₁With V _COMOutput voltage position standard between value to obtain the highest data value.The part of driven voltage schemes can be via driving voltage V _COMOr the V of pixel _CAPBe used on the pixel, and preferably can be with V ₁Value be limited to minimum and the maximum data value, as shown in figure 11.

For dropping on one than the data value between a low value (threshold value A) and the high value (threshold value B), voltage source V ₂Output voltage position standard be to be set as to be equal at voltage level V _CMVoltage source V _COMOutput voltage position standard, and voltage source V ₁The output voltage position will definitely change with control pixel brightness.

For the data value that is lower than threshold value A, voltage source V ₁Output voltage position standard during a positive addressing, be to be limited to a voltage level V _MIN3, then be to be limited to a voltage level V during a negative definite location _MAX3Voltage source V ₂Output voltage position standard be to be set as one between voltage source V ₁The output voltage position accurate with the accurate V in average common electrode voltage position _CMBetween value, this numerical value is shared at electric charge and is selected after carrying out, in order to produce needed voltage on the LC capacitor.

For the data value that exceeds threshold value B, voltage source V ₁Output voltage position standard during a positive addressing, be to be limited to voltage level V _MAX3, during a negative definite location, then be to be limited to voltage level V _MIN3Voltage source V ₂Output voltage position standard be set as one once again between voltage source V ₁The output voltage position accurate with the accurate V in average common electrode voltage position _CMBetween the position accurate, this numerical value is shared at electric charge and is selected after carrying out, in order to the needed voltage of generation on the LC capacitor.

Therefore, when keeping the advantage of electric charge driving method for most image data value, voltage source V ₁The scope of output voltage position standard can be reduced.

Comprehensive speech, the present invention not only proposes drive scheme, fixed method makes the pixel addressing to disobey the value of liquid crystal capacitance amount across the voltage drop at LC capacitor two ends, reach the problem of eliminating the pixel switching delay by this, also revise the switching behavior of pixel in the mode of a control, show and switch or performance during mobile image to improve display in response to the change of display operation situation.In addition, the present invention reduces the power consumption of pixel also in conjunction with the control of drive scheme with common electrode voltage.

After describing preferred embodiment of the present invention in detail, those skilled in the art can clearly understand, and can carry out various variations and change not breaking away under claim and the spirit, and the present invention also is not subject to the embodiment of illustrated embodiment in the instructions.

Claims

1. a transient state controlling and driving method is characterized in that, described transient state controlling and driving method is urged to one second voltage level in order to the liquid crystal capacitor with an image element circuit from one first voltage level, said method comprising the steps of:

Described liquid crystal capacitor is urged to a medium voltage position standard from described first voltage level; And

Described liquid crystal capacitor is urged to described second voltage level from described medium voltage position standard.

2. transient state controlling and driving method as claimed in claim 1 is characterized in that, described liquid crystal capacitor is to be urged to described medium voltage position standard by one first power supply from described first voltage level.

3. transient state controlling and driving method as claimed in claim 1 is characterized in that described liquid crystal capacitor is to be urged to described second voltage level by a second source from described medium voltage position standard.

4. transient state controlling and driving method as claimed in claim 1, it is characterized in that, further the reservior capacitor with described image element circuit is urged to a tertiary voltage position standard, and to follow described liquid crystal capacitor be to be urged to described second voltage level via sharing with an electric charge of described reservior capacitor.

5. transient state controlling and driving method as claimed in claim 1 is characterized in that, it is punctual to be driven to described medium voltage position at described liquid crystal capacitor, resets the voltage drop at described liquid crystal capacitor two ends.

6. transient state controlling and driving method as claimed in claim 1 is characterized in that, the described second voltage level correspondence is from a brightness value that described image element circuit received.

7. transient state controlling and driving method as claimed in claim 6 is characterized in that, the described brightness value that the voltage level correspondence that the described voltage drop at described liquid crystal capacitor two ends has is received.

8. a transient state control Driver Circuit is characterized in that, described transient state control Driver Circuit is urged to one second voltage level in order to the liquid crystal capacitor with an image element circuit from one first voltage level, and described circuit comprises:

Described liquid crystal capacitor;

One reservior capacitor, it is electrically coupled to described liquid crystal capacitor; And

One switchgear, in order to control described reservior capacitor so that it is driven to a tertiary voltage position standard, control described liquid crystal capacitor so that it is urged to a medium voltage position standard from described first voltage level, and control described liquid crystal capacitor so that it is by sharing with described reservior capacitor one electric charge and being urged to described second voltage level from described medium voltage position standard.

9. transient state control Driver Circuit as claimed in claim 8, it is characterized in that, described switchgear comprises one first switch, one second switch and one the 3rd switch, described reservior capacitor controlled by wherein said first switch so that it is urged to described tertiary voltage position standard, described second switch controls described liquid crystal capacitor so that it is urged to a medium voltage position standard from described first voltage level, described the 3rd switch is controlled described liquid crystal capacitor and is shared with the electric charge between described reservior capacitor, and controls described reservior capacitor described liquid crystal capacitor is urged to described second voltage level from described medium voltage position standard.

10. transient state control Driver Circuit as claimed in claim 8, it is characterized in that, described switchgear comprises one first switch and a second switch, described first switch is controlled described reservior capacitor and is electrically coupled to one first power supply, be urged to described tertiary voltage position standard to control described reservior capacitor, described second switch is controlled described reservior capacitor and is electrically coupled to described liquid crystal capacitor, shares with the electric charge between described reservior capacitor to control described liquid crystal capacitor.

11. transient state control Driver Circuit as claimed in claim 8 is characterized in that, to be driven to described medium voltage position punctual when described liquid crystal capacitor, and the voltage drop at described liquid crystal capacitor two ends is reseted.

12. transient state control Driver Circuit as claimed in claim 8 is characterized in that, the described second voltage level value correspondence is from a brightness value that described image element circuit received.

13. transient state control Driver Circuit as claimed in claim 8 is characterized in that, the described brightness value that the voltage level correspondence that the voltage drop at described liquid crystal capacitor two ends has is received.

14. an image display system is characterized in that, described image display system comprises:

A plurality of image element circuits, each image element circuit have a transient state control Driver Circuit as claimed in claim 8;

One first voltage source is in order to be urged to described reservior capacitor described tertiary voltage position standard; And

One second voltage source is in order to be urged to described medium voltage position standard with described liquid crystal capacitor by described first voltage level.

15. image display system as claimed in claim 14, it is characterized in that described image display system is a mobile phone, a digital camera, a personal digital assistant, a notebook computer, a desktop computer, a TV, a GPS, an automobile-used display, an aviation display, a digital frame or a Portable DVD projector.