CN1864093A - Liquid crystal display unit and driving method therefor and drive device for liquid crystal display panel - Google Patents
Liquid crystal display unit and driving method therefor and drive device for liquid crystal display panel Download PDFInfo
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Abstract
The polarity inversion cycle of a voltage applied to a liquid crystal layer is set to at least 2-frame cycle, or more preferably to as long as about 10 sec. Accordingly, a flicker that could not have been prevented at a polarity inversion cycle of about one frame can be prevented, and a longer inversion cycle can reduce power consumption. A material low in ion reactivity and small in residual polarization is used as a liquid crystal material or an orientation film material, thereby preventing the occurrence of a residual DC component in a liquid crystal layer and the deterioration of display quality despite a longer polarity inversion cycle. In the case of an LCD provided with a minimal transmittance with respect to an applied voltage, black can be accurately displayed by, for example, regulating a common electrode potential so that an applied voltage at which the transmittance of a liquid crystal shows a minimum value during an anodic application period is equal to that during a cathodic application period.
Description
Technical field
The present invention relates to a kind of liquid crystal indicator, relate in particular to the reversal of poles of the voltage that puts on liquid crystal layer.
Background technology
Can frivolous little shape and the liquid crystal indicator of low power consumption, the display that is used as various machines at present uses.The face that this liquid crystal indicator (hereinafter referred to as LCD (Liquid Crystal Display)) possesses 2 opposite faces is provided with between the substrate of electrode and encloses the structure that liquid crystal is fitted and formed, and, between electrode, apply voltage signal, control is because of the different liquid crystal alignings that optical characteristics is changed of directed state, and control shows whereby from the penetrance of the light of light source.
At this, if when continuing between the electrode of the opposite side that is arranged at substrate, to apply DC voltage, then the directed state of liquid crystal molecule is fixed, promptly can produce the problem of so-called ghost, therefore, adopted the ac voltage signal that the polarity of reference voltage is produced periodic inversion, as the voltage signal that drives liquid crystal in the past.
Known is, the sequential of the reversal of poles of this liquid crystal drive voltage signal is the counter-rotating during the counter-rotating of (or 1 field interval) during the counter-rotating during per 1 block diagram, per 1 vertical scanning (1V), the counter-rotating during per 1 horizontal scanning (1H) and per 1 pixel (1 point) in the liquid crystal indicator with rectangular arrangement plurality of pixels.During 1 block diagram for example be, with the NTSC signal be 1 block diagram during, 1 field interval is equivalent to constitute (for example odd field and even field) during several each of 1 block diagram.But in LCD, adopt as in the past known to CRT (Cathode Ray Tube, cathode-ray tube (CRT), claim iconoscope again) display packing of display device, in during 1 block diagram, the horizontal scanning line that drives odd numbered with odd field reaches the horizontal scanning line that drives even number with even field, in adopting mostly during 1 block diagram, drive the method for whole pixels (horizontal scanning line of odd number and even number) of several times (for example 2 times) successively, in this case, 1 field interval (or 1 vertical scanning period) be equivalent to the number of times that drives whole pixels remove during 1 block diagram during.
Figure 12 shows 1 pixel about LCD, while the change of the penetrance of driving voltage waveform when carrying out the reversal of poles of liquid crystal drive voltage driving in each field interval and liquid crystal.In this example, adopt active-matrix type (the active matrix type) LCD that possesses thin film transistor (TFT) (TFT) in each pixel to be used as LCD, and double team liquid crystal layer and relative therebetween with each pixel electrode, and for the voltage signal that puts on the common electrode that forms jointly by each pixel (common voltage signal) Vc, shown in Figure 12 (a), in the field interval in during per 1 block diagram, to be applied in be connected in TFT and in each pixel by the display voltage V of the formed pixel electrode of indivedual patterns
p, carry out reversal of poles.
In Figure 12, adopt often white mode (normally white) as liquid crystal, and in supposing during each block diagram, the pixel of being watched attentively is carried out identical black display.
Owing to the penetrance of the liquid crystal layer among the LCD absolute value by the voltage that puts on this liquid crystal layer determines, therefore when carrying out identical black display, preferably, during positive polarity field and negative polarity field interval among both, the absolute value of the potential difference (PD) of display voltage Vp and common electrode current potential Vcom is equal.Yet the waveform of display voltage Vp that in fact is applied to pixel electrode during positive polarity field and in the negative polarity field interval, does not present balancing waveform completely shown in Figure 12 (a).One of its reason is with the value shown in the Δ V, to reach negative polarity field interval difference during positive polarity field among Figure 12 (a).
Δ V is represented with following (2) formula.
Δ V=Vg * (Cg/ (Clc+Csc+Cg)) ... (2) formula
Figure 13 shows, equivalent electrical circuit in each pixel of active-matrix type LCD, illustrate with reference to Figure 13, the Vg of above-mentioned (2) formula represents, put on the scanning voltage signal (signal voltage) of this gate electrode for the TFT that selects each pixel, Cg is shown in the gate electrode of TFT and the grid stray capacitance between the source region, Clc represents liquid crystal capacitance, Csc represents to be connected side by side with liquid crystal capacitance, and till selecting pixel and writing shows signal during, keep the maintenance electric capacity of shows signal.
With so that carry out the polarity of the signal voltage of turn-on action in each pixel as the set TFT of changeover module, even all identical during positive polarity field or in the negative polarity field interval (is positive polarity at this).Therefore, applying signal voltage Vg, and writing in pixel electrode during the positive polarity field of display voltage Vp of positive polarity, and writing in the negative polarity field interval of display voltage Vp of negative polarity, the symbol of Δ V equates.Moreover, owing to making Clc, the voltage that puts on liquid crystal layer changes, follow in this Δ V and also change, therefore during positive polarity field and in the negative polarity field interval, make the virtual voltage that puts on liquid crystal produce gap easily, the gap of virtual voltage then becomes the time shifting of LCD penetration, in case this time displacement when 1 block diagram produced in the cycle, then the observer can see the scintillation in the demonstration.
In addition, during positive polarity and in during the displacement during the negative polarity, be accompanied by the change of the current potential of display voltage Vp, in fact put in the voltage waveform of liquid crystal, produce in response to the waveform skew that mainly keeps the time constant that electric capacity determined by liquid crystal capacitance Clc and Csc.Moreover, because the change in voltage that in fact the directed state of liquid crystal should be applied, and follow liquid crystal and change with intrinsic response speed, therefore, till in fact the penetrance of liquid crystal changes, need some times of cost from voltage application.Therefore, penetrance is accompanied by the generation change of periodic reversal of poles easily lentamente.
From above reason, if adopt the method in each, carry out reversal of poles, the directed state of liquid crystal molecule then, i.e. penetrance can be followed during the positive polarity field and the carrying out of negative polarity field interval and produce great change shown in Figure 12 (b).With regard to the characteristic of people's naked eyes, driving frequency probably when 50Hz is following, is then confirmed scintillation easily, therefore if produce during the frequency of the change of penetrance below 50Hz, then can produce flicker.Therefore, in order to reduce flicker, be not only each the reversal of poles shown in Figure 14 (a), more be necessary to carry out vertical scan line (V line) counter-rotating, the horizontal scanning line shown in Figure 14 (c) (H line) counter-rotating, the some counter-rotating shown in Figure 14 (d) shown in Figure 14 (b) etc., the time fluctuation cycle of reducing the LCD penetrance whereby.
On the other hand, the various machines that more require to be equipped with LCD further reduce consumption electric power, thereby LCD itself is also required low power consuming, about reaching the method for low power consuming, in the LCD that adopts AC driving, reduce this driving frequency and can be considered effective means.Yet as mentioned above, in LCD in the past, in general display mode, in order to keep display quality, what override was considered is, suppresses the generation of the flicker that caused because of the reaction velocity of liquid crystal, the asymmetry of driving voltage waveform, the generation of residual DC etc.In addition, in the reversal of poles of field duration, produce penetrance change, may confirm flicker greatly and have as the above-mentioned about 30Hz frequency that is equivalent to the block diagram frequency.Therefore, in requiring the general display mode of high display quality, do not attempt reducing the reversal of poles frequency.
In addition, in LCD in the past, in case when applying the display voltage Vp of the above same polarity of 2 field intervals, residual DC (DC voltage) part that then puts on liquid crystal layer is very big, even the display voltage Vp that therefore applies the corresponding displaying contents that should put on liquid crystal originally is to pixel electrode, can't show suitably that also in addition, this residual DC also can produce the problem that scintillation duration is prolonged.
Summary of the invention
The present invention is to possess 2 substrate of the electrode that liquid crystal drive uses on the opposite side respectively, double team liquid crystal layer and relatively configuration constitutes, and possess the liquid crystal indicator (LCD) and the driving method thereof of plurality of pixels, more than during 2 block diagrams, in each pixel, the liquid crystal drive voltage that will put on liquid crystal layer with respect to special datum maintains same polarity.
In others of the present invention, LCD and driving method thereof possess and have: according to picture signal, output puts on the liquid crystal driving signal handling part of the liquid crystal drive voltage of liquid crystal layer; Judgement is during through 2 block diagrams between above given period, the scheduled period detection unit of the reversal of poles control signal of the above-mentioned liquid crystal drive voltage polarity of output counter-rotating, according to above-mentioned reversal of poles control signal, the reverse polarity of above-mentioned liquid crystal drive voltage of above-mentioned liquid crystal driving signal handling part, in each pixel, more than during 2 block diagrams,, the liquid crystal drive voltage that puts on liquid crystal layer is maintained same polarity with respect to predetermined benchmark.
In other aspects of the present invention, above-mentioned liquid crystal drive voltage is maintained same polarity during more than 10 seconds.
In others of the present invention, above-mentioned scheduled period detection unit possesses the adjustment part of any above-mentioned scheduled period of adjustment.
In others of the present invention, the reversal of poles of above-mentioned liquid crystal drive voltage is least unit during driving with 1 picture during the driving of whole pixels of being equivalent to above-mentioned plurality of pixels.
In others of the present invention, in above-mentioned LCD, during will put on above-mentioned liquid crystal layer with same polarity between the t maximum when applying voltage Vpmax and putting on above-mentioned liquid crystal layer, the remnant DC voltages Vdc that is produced in above-mentioned liquid crystal layer satisfies following (1) formula.
Vdc≤0.1 * Vpmax......... (1) formula
In others of the present invention, the above-mentioned liquid crystal drive voltage of the positive polarity that above-mentioned liquid crystal layer applied is equated with the application time of the above-mentioned liquid crystal drive voltage of negative polarity.
In others of the present invention, above-mentioned LCD possesses, and has minimizing characteristic with respect to the penetrance that applies voltage.
In others of the present invention, above-mentioned LCD moves in electric field controls birefringence pattern.
In others of the present invention, possess the penetrance that applies voltage relatively and have minimizing characteristic, in black display, electrode potential with respect to relative substrate, the liquid crystal drive current potential that puts on above-mentioned liquid crystal layer is during positive polarity and negative polarity, for making it become the potential difference (PD) that absolute value equates, and set the electrode potential of above-mentioned relative substrate.
In other aspects of the present invention, above-mentioned LCD is with respect to being applied to each pixel polarity of the special datum of the voltage of the pixel electrode of formation separately, reverse in cycle more than during above-mentioned 2 block diagrams, the voltage that is applied on the relative common electrode of seizing pixel electrodes and above-mentioned liquid crystal layer on both sides by the arms is certain, with respect to the polarity of the special datum that is applied to the liquid crystal drive voltage on the above-mentioned liquid crystal layer, reverse in the cycle more than during above-mentioned 2 block diagrams.
In other aspects of the present invention, above-mentioned LCD is with respect to being applied to each pixel polarity of the special datum of the voltage of the pixel electrode of formation separately, reverse in cycle more than during above-mentioned 2 block diagrams, identical with the cycle of the reversal of poles of the voltage that is applied to pixel electrodes, be applied to the polarity of voltage counter-rotating on the relative common electrode of seizing pixel electrodes and above-mentioned liquid crystal layer on both sides by the arms.
In other aspects of the present invention, above-mentioned LCD has the comparative electrode drive division of the electrode that drives relative substrate, this comparative electrode drive division, in black display, be applied to liquid crystal drive current potential on the above-mentioned liquid crystal layer with respect to the electrode potential of relative substrate, the equal potential difference (PD) of absolute value is all arranged during positive polarity and negative polarity, thereby the electrode potential of above-mentioned relative substrate is set.
In others of the present invention, above-mentioned LCD possesses the adjustment part that puts on the electrode potential of relative substrate in order to adjustment.
In others of the present invention, for action or software etc. that the driving method of above-mentioned LCD can be by liquid crystal drive voltage handling part or scheduled period detection unit etc. are realized.
In others of the present invention, for driving the drive unit of above-mentioned LCD.Drive unit is constituted to several external IC chips by 1.
According to the present invention, in LCD, can prevent from the generation of glimmering and reduce to consume electric power.
Description of drawings
Fig. 1 be the expression embodiment of the invention relate to put on the reversal of poles waveform that applies voltage of liquid crystal and the accompanying drawing of penetrance.
Fig. 2 is the accompanying drawing that the summary circuit of the active-matrix type LCD1 that relates to of the expression embodiment of the invention constitutes.
Fig. 3 is the accompanying drawing that the summary circuit of the sequential control portion 130 that is used to illustrate that the embodiment of the invention relates to constitutes.
Fig. 4 is the accompanying drawing in order to the relation of explanation reversal of poles cycle and animated image display characteristic.
Fig. 5 is the accompanying drawing of the assessment result of watching mode of the expression reversal of poles cycle that relates to of the embodiment of the invention and flicker.
Fig. 6 is the accompanying drawing of the characteristic of the penetrance that applies voltage that puts on liquid crystal that relates to of the expression embodiment of the invention.
Fig. 7 be expression other embodiment of the present invention relate to put on the reversal of poles waveform that applies voltage of liquid crystal and the accompanying drawing of penetrance.
Fig. 8 is the accompanying drawing that the summary circuit of the related active-matrix type LCD2 of other embodiment of expression the present invention constitutes.
Fig. 9 is the accompanying drawing that the summary circuit of the common electrode drive portion 141 that relates to of expression other embodiments of the invention constitutes.
Figure 10 is the cut-open view of action that the expression conceptual illustration does not have VA (vertical orientation) mode LCD of polish-brush processing type (Rubbingless Type).
Figure 11 is the accompanying drawing of other examples of Figure 10 (c) of the directed cutting part of expression.
Figure 12 is that expression puts on the reversal of poles waveform that applies voltage of liquid crystal in the past and the accompanying drawing of penetrance.
Figure 13 is the accompanying drawing of the equivalent electrical circuit in 1 pixel of expression active-matrix type LCD.
Figure 14 is the accompanying drawing that concept nature is represented each reversal of poles sequential of field reversal, line counter-rotating and some counter-rotating.
Embodiment
Followingly the preferred embodiments of the present invention (hereinafter referred to as embodiment) are described with reference to accompanying drawing.
In the related LCD of present embodiment, will be set at the above cycle during 2 block diagrams with respect to the reversal of poles cycle of the reference value of liquid crystal drive voltage.Make the whole pixels that constitute 1 picture become same polarity and mean with each picture to be that unit carries out reversed polarity, and the different line in every line or each pixel of the pixel polarity in unexecuted 1 picture as above stating reverses or point reverses etc.In addition, so reversal of poles drives the active-matrix type LCD be not limited to possess switches such as TFT in each pixel, also applicable to the LCD of simple matrix type that does not possess switch etc., below, preferable with display quality, be that example illustrates especially compared to the preferable active-matrix type LCD of alternate manner quality of cartooon pictures.
Fig. 1 is illustrated under the situation of 1 pixel that is conceived to the related active-matrix type LCD of the embodiment of the invention, puts on the driving voltage waveform of liquid crystal layer of this pixel and the variation of penetrance of the LCD of this moment.In addition, Fig. 2 is the summary circuit diagram of expression active-matrix type LCD1.LCD1 comprises, 2 plate base double team liquid crystal layers are also fitted and the LCD panel 200 that constitutes, and generates LCD panel 200 action necessary drive signal, clock signals and above-mentioned signal is offered the LCD drive unit (driver LSI) 300 of LCD panel 200.
In LCD panel 200, with rectangular configuration plurality of pixels 220, as shown in Figure 2, each pixel 220 possesses TFT20 respectively, keeps electric capacity 22, liquid crystal capacitance 24 in the viewing area 210.In the present embodiment, voltage signal (common electrode current potential) Vcom of relative comparative electrode 40 (is common electrode at this) side for putting on pixel electrode 30 and double team liquid crystal layer, shown in Fig. 1 (a), to being connected in TFT20 and putting on the display voltage Vp of the pixel electrode 30 of each pixel individually, periodically carry out reversal of poles.The reversal of poles cycle of display voltage Vp, preferably during 2 block diagrams more than, more preferably than during also long during 2 block diagrams, for example be 10 seconds cycle.Adopt such reversal of poles cycle, can realize for example higher show state quality under general show state pattern.
At this, the structure that realizes the driving of above reversal of poles cycle more than during 2 block diagrams is described with reference to Fig. 2 and Fig. 3.As mentioned above, LCD1 is for enclosing liquid crystal, reducing warm polysilicon (LTPS) TFT has matrix configuration as the plurality of pixels 210 of switch element display part 210 between a pair of substrate, that is to say LCD panel 200, and generate LCD panel 200 action necessary drive signal, clock signals and above-mentioned signal is offered the LCD drive unit 300 of LCD panel 200.Relative LCD panel 200 and LCD drive unit 300, power circuit 400 is its supply capability separately.
In the present embodiment, and on the pixel TFT glass substrate that forms LCD panel 200, form level (H) and vertical (V) driver 250,260 in order to drive each image element circuit.This H driver 250, V driver 260 is arranged on the periphery of display part 210, the LTPSTFT that use and pixel are made with the almost same operation of TFT.
As the H driver 250 in the LCD panel 200 of being built among Fig. 2, the peripheral circuit of V driver 260 grades, use under the situation of a-Si (being a-SiTFTLCD) in for example pixel TFT, and under the situation for high speed, high Precision Processing requirement H driver, V driver IC chipization, these drivers can be assembled into above-mentioned drive unit 300 inside.In addition, these drivers 250,260 also can by 1 or several circumscribed drive units (IC chip) constitute.In this case, circumscribed IC chip also can pass through COB (Chip On Board, crystal grain directly welds substrate), TAB (Tape Automated Bonding, coil type crystal grain engage) mode and is installed on the glass substrate 10 and constitutes.And, adopting in the present embodiment under the situation of polycrystal silicon TFT as pixel TFT, the circuit in the drive unit 300 is all interior as shown in Figure 2 ensconces on the substrate 10 (system on substrateization (シ ス テ system on グ ラ スization)).
The below concrete structure and the action of explanation drive unit 300.At first, CPUI/F150, never illustrated CPU receives control signal (Ctrl), according to its content control signal is exported to sequential control circuit 130 etc. then.
In the present embodiment, sequential control circuit 130 has the function that is had for the scheduled period detection unit that makes reversal of poles.At this, has structure shown in Figure 3, according to Dot Clock (De Star ト Network ロ Star Network) DOTCLK, level signal same period Hsync and the vertical synchronization signal Vsync of other supply, generate H driver 250 and 260 actions of V driver in latch circuit 100, D/A change-over circuit 110, polarity handling part 120, the LCD panel 200 and show necessary clock signal and control signal (CKH, STH, CKV, STV etc.) (details aftermentioned).
D/A change-over circuit 110 will be from the latch data analog converting of latch circuit 100, and simulated data is in enlarging section 112, and amplification is to necessary amplitude (because of the situation boosted voltage).In addition, corresponding LCD characteristic is carried out the γ revisal in this enlarging section.
To then supply with polarity handling part 120 by R, G, the B simulated data of enlarging section 112 output, polarity handling part 120 is based on the polarity inversion signal PIS from sequential control circuit 130, the polarity of reverse R, G, B simulated data.Like this, at least, this simulated data that polarity is inverted in the cycle more than during two block diagrams is by 250 outputs of H driver.
Fig. 3 is the summary circuit diagram of the related time sequence control portion 130 of expression embodiments of the invention.In Fig. 3, sequential control portion 130 is by various clock signal generating units 132, and counter 134 and reversal of poles control signal generating unit 136 constitute.
Clock signal generating unit 132 serves as that the basis generates horizontal clock signal C HK and horizontal enabling signal STH with for example Dot Clock DOTCLK and level signal same period Hsync etc., and clock signal generating unit 132 serves as that the basis generates vertical clock signal CKV and vertical enabling signal STV with Dot Clock DOTCLK and vertical synchronization signal Vsync etc.In addition, though do not show among the figure, with Dot Clock DOTCLK, level signal same period Hsync and vertical synchronization signal Vsync etc., forbid that sweep signal perhaps is to the enable signal of gate line (ゲ one ト ラ イ Application (the GL)) output of LCD panel 200 etc. but generate control.
Counter 134, count each vertical synchronizing signal Vsync per 1 field, when reaching the regulation count number, reversal of poles control signal generating unit 136 output control signal CS.The regulation count number adopts, for example 4 of vertical synchronizing signal Vsync countings (situations of 2 block diagrams (field, 1 block diagram/2)) or 600 countings situation of (reach 10 seconds (the about 30Hz of block diagram frequency, a field, 1 block diagram/2)) etc.In addition, counter 134 also can add the counter adjustment part 137 (counter 134 built-in these counter adjustment parts 137 get final product) of the predetermined count value that is used for adjusting above-mentioned counter 134 as shown in Figure 3.The counting adjusted value of this counter adjustment part 137, according to during will put on liquid crystal layer with same polarity in the t maximum when applying voltage Vpmax and putting on above-mentioned liquid crystal layer, come among the figure testing result that shows, detect the test section of the remnant DC voltages Vdc that above-mentioned liquid crystal layer produced, the relation that makes above-mentioned maximum apply voltage Vpmax and above-mentioned remnant DC voltages Vdc satisfy following (1) formula during in with the self-adjusting structure of mode.For example, this adjustment can be adopted following method, t will be set in ROM, the RAM etc. as condition list etc., when driving LCD, measure temperature, according to as a result the adjustment period between t.
Vdc≤0.1 * Vpmax......... (1) formula
Reversal of poles control signal generating unit 136 is according to control signal CS, and output polarity reverse control signal PIS is to polarity handling part 120.Counter 134 also can be made of timer 135.At this moment, timer 135 is in each scheduled period (for example per 10 seconds), and CS is to reversal of poles control signal generating unit 136 for the output control signal.The schedule time value of above-mentioned timer 135 is adjusted in timer adjustment part 138.In addition, adopt timer 135, reversal of poles control signal generating unit 136 receives the output control signal CS of self-timer 135, in this case and control signal vertical synchronization signal Vsync output polarity same period reverse control signal PIS.
The reversal of poles control signal PIS that is obtained according to the method described above, in sequential control circuit 130 input polarity handling parts 120, as mentioned above, polarity handling part 120 is based on this reversal of poles control signal PIS, the polarity of counter-rotating simulated data, the data that obtained are exported at the H driver 250 that should obtain signal as the demonstration line pressure Vp of each data line DL of LCD panel 200.
The common electrode drive portion 140 of drive unit 300 generates and supplies with the common electrode current potential Vcom that gives common electrode 40.For example, will boost to suitable current potential from the supply voltage process of power circuit 400, the voltage after then this being boosted is exported as common electrode current potential Vcom.The height of common electrode current potential Vcom has equal potential difference (PD) respectively with respect to positive polarity height and the negative polarity height of the display voltage Vp that is used for representing black display under the white mode (Normally WhiteMode) often.That is setting the Vcom current potential when, adjustment part 149 is with black display makes the voltage that puts on liquid crystal in during the positive polarity and during the negative polarity equal potential difference (PD) being arranged all.And, this setting also can be, in black display, according to coming from the testing result that detects the test section voltage that puts on liquid crystal, that do not show among the figure, for making during reaching negative polarity during the positive polarity equal potential difference (PD) is arranged all, and adjust the structure of Vcom current potential automatically.
Below, be that digital signal, employing numeral are that example describes with drive unit 300 with incoming video signal, be under the situation of simulating signal still at incoming video signal, adopt simulation drive unit 300.In this case, sequential control portion 130 utilizes the signal of the supplying with same period to make the necessary clock signal and the reversal of poles control signal PIS of specified period, the polarity handling part is installed in the drive unit 300, counter-rotating is supplied with H driver 250 through R, the G of γ revisal, the polarity of B analog video data.
Analog video or digital video during the video no matter imported, in LCD drive unit 300, when video data is carried out digital processings such as γ revisal and reversal of poles, handle directly digital of digital video data being carried out these, finally on the circuit as the demonstration line pressure Vp input of each data line DL of LCD panel 200 lion simulation (D/A) converter section is set.For example, can D/A converter section (on the interior plant substrate 10) be set between H driver 250 and the viewing area 210.
Then, non-ly apply that to carry out often white mode often (the Normally White Mode) liquid crystal that white shows under the voltage status (dissengaged positions) be that example illustrates.Under common show state, be conceived to keep under the situation of certain pixel of black display state, on the pixel electrode 30 of this pixel, be applied to the shows signal shown in the Vp that is less than 1 Fig. 1 (a) during the block diagram.
As mentioned above, at H driver 250 places, by sequential control circuit 130 horizontal clock signal C HK of output and horizontal enabling signal STH.In addition, H driver 250 has the variable resistor of plurality of sections, be that clock is successively in the horizontal enabling signal STH of transmission with horizontal clock signal C HK, the corresponding horizontal enabling signal STH output Continuous Selection signal that transmits by each section resistance, to reading the display data signal (Vp) of drive unit 300 outputs successively by signal Continuous Selection circuit, in corresponding data line DL place output this display data signal (Vp).
During the output scanning signal, conducting connects the TFT20 of the pixel 220 of this gate line gate electrode, be connected in this TFT 20 source electrode pixel electrode 30 and keep the current potential of an electrode in the electric capacity 22, can become the current potential of data line DL that correspondence is connected in the drain electrode of this TFT 20, promptly become the current potential of corresponding display data signal current potential.The waveform of display voltage Vp shown in Fig. 1 (a) is, from data line DL via TFT 20 the actual voltage waveform that puts on each pixel electrode 30.
In each pixel electrode 30,,, export 1 time high (H) sweep signal highly to pairing gate lines G L, and newly write display data signal via TFT 20 to being less than 1 vertical scanning period (1 field) according to above-mentioned V driver 260.Therefore, when writing, put among the display voltage Vp of pixel electrode 30, can produce the variation in voltage Δ V shown in above-mentioned (2) formula.On display voltage Vp, produce so variation in voltage Δ V, with identical in the past.Yet, in the present embodiment, owing to, will have comparative electrode current potential Vcom to be maintained same polarity for this display voltage Vp through during several block diagrams, therefore in during the display voltage Vp that applies same polarity, the voltage that in fact puts on liquid crystal layer produces change hardly.Therefore, shown in Fig. 1 (b), during the polarity of display voltage Vp is identical in the change of penetrance of LCD, relatively Figure 12 (b) obviously learns, changes minimum and can not produce flicker during this period.In addition, shown in Figure 12 (b), under the situation of each Semi-polarity counter-rotating, though produce the change (i.e. flicker) of the penetrance in 1 block diagram cycle, but in the present embodiment, the penetrance of the LCD less cycle of change is 1 field duration, and the variable cycle of penetrance shortens to 1/2, thereby can prevent that naked eyes from finding out scintillation.So, in the present embodiment,, therefore can positively prevent because of producing the contrast reduction that flicker causes owing to do not produce flicker.
Display voltage Vp during several block diagrams, for example after keeping same polarity between 10 seconds (during the positive polarity of Fig. 1), identical to the absolute value of the potential difference (PD) of common electrode current potential Vcom, and Vcom is reversed to the height (during the negative polarity) of antipolarity.Identical for making the actual effect that between each polarity epoch, puts on liquid crystal apply voltage, preferably, make during the positive polarity and negative polarity during time length identical, in addition, shows signal (display voltage Vp) was preferably between each polarity epoch, was set at the AC signal that Vcom is only equated for the different but absolute value of symbol.In the example of Fig. 1, under white morphotype formula often, adopt the positive polarity height of display voltage Vp of expression black display and the mode of the potential difference (PD) that the negative polarity height equates respectively, and set the height of Vcom.That is, in black display, the voltage that puts on liquid crystal is equal potential difference (PD) during positive polarity and in during the negative polarity, set the Vcom current potential by this way.
Shown in Fig. 1 (b), the penetrance of LCD changes significantly changing in a flash along be transferred to the virtual voltage that puts on liquid crystal during the negative polarity during positive polarity.Yet, in case after the reversal of poles, continue with non-reversed polarity during during identical several block diagrams (during for example about 300 block diagrams).Therefore the change of penetrance in during this shifts, and can't be confirmed to be flicker.So, in the present embodiment, by the cycle with reversal of poles be set at during several block diagrams above long-term between, and can prevent flicker.
As mentioned above, in the counter-rotating of in the past H line, put on the positive polarity of voltage of liquid crystal layer and the absolute value difference of negative polarity.At this moment, watching under the situation of rest image, even the absolute value difference of voltage but because human naked eyes reach the restriction of the capacity of decomposition on the space in time, reaches equalization in the brightness of adjacent pixels, thereby is difficult to confirm that the brightness of every line changes.Yet, watching under the situation of dynamic image, follow the action of dynamic image easily owing to the tracking eye movement of naked eyes.When illustrating with reference to Fig. 4, then at the x composition Vx of the velocity vector V of dynamic image near in following (3) formula,
N * P/t......... (3) formula
On the same position on the eyeball retina, the horizontal line of positive polarity and the horizontal line of negative polarity can be tied picture, and confirm that every horizontal brightness changes.In (3) formula, n is a positive integer, and P is the pel spacing of vertical direction, and t is the time of 1 block diagram.In addition, can learn, in V line counter-rotating, in case Vy during near the value of above-listed (3) formula, confirms that then the brightness of every perpendicular line changes by same principle.Under the situation of V line counter-rotating, the P of above-mentioned (3) formula is the pel spacing of horizontal direction.In addition, under the situation of a counter-rotating, can learn that by the principle identical the display characteristic of animation can variation with the situation of above-mentioned H line counter-rotating and the counter-rotating of V line.So, under the situation that adopts the counter-rotating of H line, the counter-rotating of V line or the counter-rotating of some counter-rotating isopolarity, when showing motion video, the action of image and line counter-rotating or the cycle synchronisation of some counter-rotating, and the demonstration of animated image is worsened.Yet, as present embodiment, do not carry out line counter-rotating and some counter-rotating, and carry out reversal of poles with the cycle above during 2 block diagrams, whereby, because in during 1 block diagram when watching, all the video data polarity of pixels is identical, therefore can't produce dynamic image and show deterioration, and can obtain good animated characteristics.
Fig. 5 is the accompanying drawing of the assessment result of watching mode of expression reversal of poles cycle and flicker.This relation in the 2.5 type LCD that adopt low temperature polycrystalline silicon TFT as changeover module, is 150cd/m with surface brightness
2LCD, be least unit (promptly not carrying out line counter-rotating or some counter-rotating) with the drive cycle (is 1 field duration at this) of 1 picture, the degree of watching mode of glimmering when changing cycle of reversal of poles is carried out the result after the assessment in 5 stages by some people.Returing cycle is also long and produce flicker than 7 seconds, is the 4th, 5 grade of being equivalent to almost not discover or can not discover fully.So, for the generation that prevents to glimmer, preferably prolonging returing cycle, preferably, is more than 7 seconds, and better is more than 10 seconds.The block diagram frequency is about 30Hz, is about 0.03 second during 1 block diagram.Therefore, returing cycle is 10 seconds, and the block diagram number is about 300 block diagrams.Constituting with 2 fields under the situation of 1 block diagram, 1 field interval is half 0.015 second.And under the above situation about being constituted with the n more than 3, then become (each field interval is difference each other) during should number of fields.
Can learn that from Fig. 5 the cycle that prolongs reversal of poles can reduce the generation of flicker.On the other hand, owing to put on liquid crystal between DC voltage is long-term, then be necessary to further consider whether can produce original employing and exchange inversion driving and will avoid, apply generation that causes ghost and the problem that can't apply appropriate display voltage because of the residual DC that puts on liquid crystal.In order to keep display quality, the residual DC (Vdc) that puts on liquid crystal preferably is set in, and the maximum that puts on liquid crystal layer applies under the situation that voltage Vpmax is applied in the counter-rotating of period T polarization, satisfies in the scope of following (1) formula.
Vdc≤0.1 * Vpmax......... (1) formula
If residual DC components is set at maximum and applies below an one-tenth of voltage Vpmax, then can reduce influence, and this liquid crystal material and the oriented film that can pass through to be adopted wait corresponding to showing.Possess among the minimizing LCD in often white mode and penetrance, maximum applies voltage Vpmax and is equivalent to the black display height.
About liquid crystal material, preferably, adopt the material that stability of molecule is higher and ionic reaction is lower, for example can adopt in the liquid crystal terminal groups to possess liquid crystal molecule fluorine-based or the fluorine compounds base.In addition, also can adopt the lower liquid crystal molecule of specific inductive capacity.Require the lower reason of ionic reaction to be, even it is longer during the applying of DC voltage, also can prevent liquid crystal molecule generation chemical reaction and orientation direction is fixed, just prevent the generation of so-called ghost, in addition, lower specific inductive capacity can promote the reaction velocity to the liquid crystal of the variation of liquid crystal drive voltage, and is not easy in the influence that is subjected to once applying voltage during the following display.
About oriented film, preferably lower thickness.Oriented film is to coat the mode of pixel electrode and common electrode respectively, be formed on the face that contacts with liquid crystal layer one side of 2 plate bases, be used for the initial stage orientation of liquid crystal (no-voltage apply etc. liquid crystal aligning) is controlled at desirable direction (forming the oriented film 32 of Figure 10 described later that the position can reference).About this oriented film 32, generally adopt polyimide insulating material such as (Polyimide).Therefore, if the thickness of oriented film 32 is thicker, the voltage that then is supplied to pixel electrode and common electrode is difficult for being applied on the liquid crystal layer, for make the virtual voltage that puts on liquid crystal layer reach can corresponding displaying contents appropriate voltage, thereby must take a long time, and cause the residual DC that puts on liquid crystal layer easily.Therefore, with respect to the thickness that adopts 70 to 80nm in the general oriented film in the past, the thickness of the oriented film 32 in the present embodiment is extremely thin 20 to 30nm, so can promote the voltage that puts on liquid crystal layer and apply precision, and suppress the generation of residual DC.
In addition, because residual DC also depends on the material of oriented film, so oriented film must be at least the material of few generation impurity ion, and in addition, preferably, remnant polarization is extremely low.
As an example, in the present embodiment, the fluorine that liquid crystal material adopts Japanese Chisso company to make is liquid crystal trade name (SA5097), liquid crystal layer to palm isomery spacing (ChiralPitch)=40 μ m, Δ ε=5.5, Δ n=0.129 is by adopting this material, under the situation that can be set at 10 seconds, prevent the generation of residual DC in the reversal of poles cycle with liquid crystal drive voltage.In addition, oriented film in the case, the trade name (JALS1085) that adopts Japanese JSR company to make, the thickness setting of oriented film is 20nm.
Certainly be not limited to above-mentioned example about liquid crystal material and oriented film, in addition, also be not limited to liquid crystal material and oriented film in order to the adjustment object that lowers residual DC components, no matter be which kind of situation, preferably, residual DC components can be suppressed in the scope that satisfies above-mentioned (1) formula.
At this, the LCD that is adopted is the LCD of present widely used TN (TwistedNematic, twisted nematic) pattern in the present embodiment, and is in addition, above-mentioned in the non-what is called that applies display white under the state of voltage white mode often.
In the present embodiment, except above-mentioned TN pattern, also can adopt for example electrically conerolled birefringence (ECB:Electrically Controlled Birefringence) pattern, promptly utilize refractive index poor of the major axis of liquid crystal molecule and minor axis, be so-called birefringent phenomenon, the mode of the penetrance of the light that the past liquid crystal layer of employing control is injected.In this ecb mode, for example with the form of directed State Control of the initial stage of liquid crystal in almost parallel state (horizontal direction of base plan), possess having for applying the voltage penetration rate and possess minimizing characteristic as shown in Figure 6, moreover, in non-display white under the state, the so-called white mode often of applying of voltage.
About as shown in Figure 6, have for applying the voltage penetration rate and possess minimizing liquid crystal, except above-mentioned ecb mode, also has OCB (0ptical Compensated Birefringence, optical compensation birefringence) pattern, and because of the different STN of torsional angle (Super Twisted Nematic, STN Super TN) pattern etc.
Possess (ECB, OCB, STN etc.) among the minimizing LCD in penetrance,, then can't carry out black display, cause showing the reduction of contrast in case make the voltage deviation appropriate value that puts on liquid crystal layer in order to make penetrance reach minimum.In the present embodiment, more than reversal of poles being extended for during 2 block diagrams, can reduce the generation of flicker.Therefore, possess among the minimizing LCD in penetrance, do not need the special flicker of considering, and show that the absolute value of the minimum magnitude of voltage of penetrance during reaching negative polarity during the positive polarity equates as long as adjust to make, this control is very easy, and can carry out black display really, and realize the demonstration of high-contrast.
Even be the LCD of white mode often, for applying among the LCD that the voltage penetration rate do not possess minimizing above-mentioned TN pattern, as long as apply enough big voltage when black display, generation is more or less irregular even this applies voltage, also can carry out black display.On the other hand, in case carry out the words of reversal of poles as before under the cycle at 1 block diagram, then produce flicker, and in order to make flicker become not conspicuous as far as possible, be necessary to adjust reversal of poles, specifically be during positive polarity applies and during negative polarity applies, the absolute value of the voltage of color range in the middle of showing is put on the liquid crystal layer.With respect to this, have for applying among the LCD that the voltage penetration rate possesses minimizing characteristic above-mentioned, as mentioned above so that show the minimum magnitude of voltage of penetrance in during the positive polarity and the mode that equates of the absolute value during the negative polarity adjust.In the present embodiment, do not possess in the minimizing TN pattern,, can be used in during the positive polarity and during the negative polarity yet, cooperate to show that penetrance be the absolute value of magnitude of voltage of the black height of minimum even under white mode often in penetrance.Can carry out black display really whereby, and promote contrast.
About showing the adjustment of the magnitude of voltage that penetrance is minimum, be actually based on considering to be arranged on the positive polarity display data signal of the TFT between data line and the pixel electrode and the through characteristic of negative polarity display data signal, and for example result from the waveform skew etc. of display data signal of the Δ V shown in above-mentioned (2) formula etc., adjust the current potential of common electrode current potential Vcom by adjustment part 149, whereby during the positive polarity and during the negative polarity, the black display voltage that the puts on liquid crystal absolute value of the potential difference (PD) of Vp (Vcom with) is set for equating.Among the TFT in exploitation at present, owing to can't make the reception and registration characteristic of positive signal between drain electrode, source electrode and negative polarity signal identical, therefore, the display data signal waveform itself is difficult to becoming object waveform completely during reaching negative polarity during the positive polarity.Yet, in the present embodiment, possess adjustment part 149, by adjusting common electrode current potential Vcom, can make the absolute value of the virtual voltage that puts on liquid crystal layer equal as much as possible simply during the positive polarity and during the negative polarity.
At this, about putting on the polar inversion method that applies voltage of liquid crystal, often keeping under the fixing situation of common electrode current potential Vcom, the method that the polarity of the display voltage Vp that only reverses is arranged reaches the method that together changes the current potential of common electrode current potential Vcom with the reversal of poles of display voltage Vp.
In the above description, be that example is illustrated with situation about as shown in Figure 1 common electrode current potential Vcom being maintained fixed.
Yet, also can together use the method for the current potential of counter-rotating common electrode current potential Vcom.Fig. 7 represents, the common electrode current potential Vcom that reverses like this when observing 1 pixel of active-matrix type LCD, is applied to driving voltage waveform and the variation of LCD penetrance at that time on the liquid crystal layer of this pixel.Counter-rotating common electrode current potential Vcom considers from the common electrode side, is necessary to prepare at least 2 Vcom power supplys, and the circuit (with reference to Fig. 9 described later) that possesses the output potential that switches Vcom, in addition, because reversal of poles, the situation that consumption electric power is compared not counter-rotating is also high.
Yet, in the present embodiment, because the cycle of reversal of poles is very long, as long as thereby can reduce the increment that consumes electric power.In addition, consider that when the reversal of poles of display voltage Vp, the reversing of common electrode current potential Vcom is the opposite polarity polarity with display voltage Vp from the TFT side.Therefore, even shown in the oscillogram of Fig. 7 (a), lower the amplitude of display voltage Vp, also can be applied with the voltage of enough absolute values to liquid crystal.As mentioned above, display voltage Vp is via the TFT 20 that is arranged at each pixel, and the display data signal that will export data line DL to is supplied to the voltage of pixel electrode 30, as long as can lower the amplitude of display voltage Vp, then can lower amplitude by the alternating voltage of TFT 20, and the withstand voltage leeway of lifting TFT 20, the burden of reduction TFT 20.
Fig. 8 is that expression adopts the current potential of the common electrode current potential Vcom among above-mentioned Fig. 7 also to produce the example of summary circuit diagram of LCD2 of the method for counter-rotating, and the part identical with Fig. 2 given same-sign and omitted its explanation.The part different with Fig. 2 is reversal of poles control signal PIS input common electrode drive portion 141 places.
Fig. 9 is the summary circuit diagram of the common electrode drive portion 141 among the above-mentioned Fig. 8 of expression.In Fig. 9, the 1st common voltage generating unit 142, the 2 common voltage generating unit the 143, the 2nd adjustment parts 145,144, the 1 adjustment parts and switching SW (switch) 146.The 1st common voltage of positive polarity takes place in the 1st common voltage generating unit 142, and the 2nd common voltage generating unit 144 is to the 2nd common voltage that switches the SW146 output negative pole.
Then, in the present embodiment, the situation in a kind the VA pattern that adopts ecb mode is described.The VA pattern makes the initial stage of liquid crystal be orientated vertical direction (normal direction of substrate), and penetrance does not have minimal value.Such VA pattern also can obtain effect same as described above.Under this VA pattern, not applying polish-brush as yet at oriented film handles among the no polish-brush type LCD of (Rubbing), not only from reducing the viewpoint that consumes electric power, also from promoting the viewpoint of display quality, preferably, do not adopt 1H counter-rotating and 1 counter-rotating, and only carry out the reversal of poles during each several block diagram.Figure 10 (a) and (b) are for the summary section of the VA mode LCD of no polish-brush processing type, and as an example, expression has the profile construction of the LCD of the summary planar configuration shown in Figure 10 (c) along the A-A line.In the middle of such LCD, because oriented film is no polish-brush type, the initial stage orientation of liquid crystal does not possess tilt angle, applies under the state the non-of voltage, and the long axis direction of liquid crystal molecule is towards the normal direction of substrate and orientation.Initial stage is oriented to the liquid crystal molecule 60 of vertical direction shown in Figure 10 (a) and Figure 10 (b), in case between the common electrode 40 of LCD and pixel electrode 30, begin to apply the words of voltage, the weak electric field (line of electric force in reference to figure shown in the dotted line) that under the lower state of initial voltage, is produced then, the oblique inclinations of generation such as end at pixel electrode 30, owing to this oblique electric field, determined the tilt angle of liquid crystal molecule along with the rising of voltage.
As shown in the figure, directed cutting part 50 for example is set respectively in 1 pixel, therefore can in the several regions in 1 pixel, cuts apart different separately deflections.That is, in (iv), 1 pixel region can be divided into the zones of several different preferential visual directions, can enlarge each pixel, just the visual angle of display screen at Figure 11 described later (i).
In the example of Figure 10 (a) and Figure 10 (b), this orientation cutting part 50 can not be provided with jut on zone (opening) and the electrode and constitutes by not existing at electrode, and on the both sides respectively at common electrode 40 and pixel electrode 30, form the pattern that extends with broken line shape on the vertical direction of picture.Certainly be not limited to this pattern form, for example among Figure 11 (a) in 1 pixel region, be divided into upper end and 2 sections of lower ends at long side direction, and intersecting directed cutting part 50 in 1 pixel central authorities and just form the pattern of X word shape shown in Figure 11 (b), on this pattern, form electrode and do not have zone (opening) and jut and constitute.By so directed cutting part 50, shown in Figure 10 (a) and Figure 10 (b), can fix the border of 1 liquid crystal aligning deflection in the pixel by this orientation cutting part 50, and make the boundary position in the pixel of the deflection that the liquid crystal molecule generation is tilted different, thereby can prevent to show the unequal harmful effect that display quality is caused in each pixel and each driving sequential.
As mentioned above, in the VA mode LCD, liquid crystal molecule 60 is subjected to the electric field effects that data line DL is produced easily, this data line DL is by driving pixel electrode 30 and being formed on that the gate lines G L of the more for example TFT of lower floor and TFT be to pixel electrode 30 supply display data signal especially than pixel electrode 30, for example when every 1H carries out reversal of poles to the voltage that puts on liquid crystal, if observe the words of 1 data line DL, then during every 1H, the polarity that is supplied to the display data signal of data line DL can produce counter-rotating, shown in Figure 10 (a), for example on connection is applied with data line DL between the pixel electrode 30 of voltage of positive polarity, apply the display data signal of negative polarity, then during ensuing 1H, the polarity of the display data signal of data line DL can produce counter-rotating once more.
Therefore, shown in Figure 10 (a), leak to the electric field of liquid crystal layer, may upset the tilting electric field of the end of pixel electrode 30 from data line DL.The tilting electric field of the end of pixel electrodes 30 is the important electric fields at the orientation direction angle of regulation liquid crystal in 1 pixel region, if but because make this position deviation from the leakage electric field of data line DL etc., then in 1 pixel region, the border of the deflection of liquid crystal aligning is on the beyond thought position, promptly produce reverse tilting zone, and cause the reduction of display quality.Yet, in the present embodiment, owing to the reversal of poles cycle is set at prevents the generation of glimmering during a plurality of block diagrams, therefore need not carry out 1H counter-rotating and 1 counter-rotating, and in 1 picture, the polarity that can produce data line DL (display data signal) hardly is antipolarity to the polarity of the voltage that puts on pixel electrode 30.Therefore, shown in Figure 10 (b), not only can prevent from the generation of glimmering from also can prevent the generation of reverse inclination, and can realize that display quality is high and consume the extremely low LCD of electric power.More than, the generation and the inhibition of the reverse inclination in the VA pattern are described, but in TN pattern and ecb mode etc., the reversal of poles cycle that also can adopt present embodiment, and can suppress the generation of reverse inclination equally.
In the present embodiment, self-configuring shows at the light of panel light source behind etc. only, but also to adopt, on the both sides of pixel electrode and common electrode, adopt the penetrating type LCD of transparent conductivity electrode such as ITO, and adopt the reflective metals electrode also to reflect the reflection type LCD that shows from light from outside as pixel electrode, and when using light source, be the pattern of penetrating, when closing light source, have any pattern among the semi penetration type LCD of reflective-mode function.In reflection type LCD and semi penetration type LCD etc., further require to promote contrast, by carrying out the reversal of poles of present embodiment,, also can carry out high-contrast and show even in the middle of the reflection-type or semi penetration type LCD of ecb mode.
Utilizability on the industry
The present invention can be used for carrying the liquid crystal indicator at various e-machines.
Claims (21)
1. the driving method of a liquid crystal indicator, this liquid crystal indicator clips liquid crystal layer with 2 plate bases of the electrode that possesses liquid crystal drive respectively use on opposite side and configuration is relatively constituted, and possesses plurality of pixels, and this driving method is characterised in that,
In each pixel, the liquid crystal drive voltage that is applied to liquid crystal layer with respect to predetermined benchmark, is maintained same polarity, and its during keeping be during 2 block diagrams more than.
2. the driving method of liquid crystal indicator according to claim 1 is characterized in that, with above-mentioned liquid crystal drive voltage be maintained same polarity during be more than 10 seconds.
3. according to the driving method of any described liquid crystal indicator in claim 1 or the claim 2, it is characterized in that, during 1 picture of the reversal of poles of above-mentioned liquid crystal drive voltage during with the driving of whole pixels of being equivalent to above-mentioned plurality of pixels drives is least unit, and carries out reversal of poles.
4. according to the driving method of claim 1 any described liquid crystal indicator to the claim 3, it is characterized in that, with same polarity apply above-mentioned liquid crystal drive voltage during t be set at: the maximum that is applied to above-mentioned liquid crystal layer apply voltage Vpmax, with during with same polarity this maximum is applied the relation of the remnant DC voltages Vdc that is produced when voltage Vpmax is applied to above-mentioned liquid crystal layer in above-mentioned liquid crystal layer in the t, satisfy following (1) formula during below:
Vdc≤0.1 * Vpmax ... (1) formula.
5. according to the driving method of claim 1 any described liquid crystal indicator to the claim 4, it is characterized in that, the application time of the above-mentioned liquid crystal drive voltage of the above-mentioned liquid crystal drive voltage of the positive polarity that above-mentioned liquid crystal layer applied and negative polarity is equated.
6. according to the driving method of claim 1 any described liquid crystal indicator to the claim 5, it is characterized in that, above-mentioned liquid crystal indicator possesses the penetrance that applies voltage is had minimizing characteristic, and in black display, the electrode potential of above-mentioned relative substrate set to become make the liquid crystal drive current potential that is applied to above-mentioned liquid crystal layer electrode potential for relative substrate, during positive polarity and negative polarity, be the potential difference (PD) that absolute value equates.
7. the driving method of liquid crystal indicator according to claim 6 is characterized in that, above-mentioned liquid crystal indicator moves in electric field controls birefringence pattern.
8. according to the driving method of claim 1 any described liquid crystal indicator to the claim 7, it is characterized in that, with respect to being applied to each above-mentioned plurality of pixels polarity of the special datum of the voltage of the pixel electrode of formation separately, reverse in cycle more than during above-mentioned 2 block diagrams, the voltage that is applied on the relative common electrode of seizing pixel electrodes and above-mentioned liquid crystal layer on both sides by the arms is certain, with respect to the polarity of the special datum that is applied to the liquid crystal drive voltage on the above-mentioned liquid crystal layer, reverse in the cycle more than during above-mentioned 2 block diagrams.
9. according to the driving method of claim 1 any described liquid crystal indicator to the claim 7, it is characterized in that, with respect to being applied to each pixel polarity of the special datum of the voltage of the pixel electrode of formation separately, reverse in cycle more than during above-mentioned 2 block diagrams, identical with the cycle of the reversal of poles of the voltage that is applied to pixel electrodes, be applied to the polarity of voltage counter-rotating on the relative common electrode of seizing pixel electrodes and above-mentioned liquid crystal layer on both sides by the arms.
10. liquid crystal indicator to possess 2 plate bases of the electrode that liquid crystal drive uses respectively on opposite side, clips liquid crystal layer and configuration relatively constitutes, and possesses plurality of pixels, it is characterized in that it possesses:
According to picture signal, output is applied to the liquid crystal driving signal handling part of the liquid crystal drive voltage of liquid crystal layer;
Judgement through 2 block diagrams during the above scheduled period, output makes the scheduled period detection unit counter-rotating control part of the reversal of poles control signal of above-mentioned liquid crystal drive voltage reversal of poles; According to above-mentioned reversal of poles control signal, the reverse polarity of above-mentioned liquid crystal drive voltage of above-mentioned liquid crystal driving signal handling part, in each pixel, the liquid crystal drive voltage that is applied to liquid crystal layer is maintained same polarity with respect to predetermined benchmark, and its during keeping be during 2 block diagrams more than.
11. liquid crystal indicator according to claim 10, it is characterized in that, above-mentioned scheduled period detection unit is judged through during more than 10 seconds, and above-mentioned liquid crystal driving signal handling part is maintained same polarity with above-mentioned liquid crystal drive voltage during more than 10 seconds.
12. according to any described liquid crystal indicator in claim 10 or the claim 11, it is characterized in that, above-mentioned scheduled period detection unit judged during t be set at: the maximum that is applied to above-mentioned liquid crystal layer apply voltage Vpmax, and during with same polarity this maximum is applied the relation of the remnant DC voltages Vdc that is produced when voltage Vpmax is applied to above-mentioned liquid crystal layer in above-mentioned liquid crystal layer between the t, satisfy following (1) formula during below:
Vdc≤0.1 * Vpmax ... (1) formula.
13. according to claim 10 any described liquid crystal indicator to the claim 12, it is characterized in that above-mentioned scheduled period detection unit should be set the schedule time to be become: the application time of the above-mentioned liquid crystal drive voltage of the above-mentioned liquid crystal drive voltage of the positive polarity that above-mentioned liquid crystal layer is applied and negative polarity is equated.
14., it is characterized in that above-mentioned scheduled period detection unit possesses the adjustment part in order to any above-mentioned scheduled period of adjustment again according to claim 10 any described liquid crystal indicator to the claim 13.
15. according to claim 10 any described liquid crystal indicator to the claim 14, it is characterized in that, above-mentioned liquid crystal indicator possesses the penetrance that applies voltage is had minimizing characteristic, comparative electrode drive division with the electrode that drives relative substrate, this comparative electrode drive division, in black display, be applied to liquid crystal drive current potential on the above-mentioned liquid crystal layer with respect to the electrode potential of relative substrate, the equal potential difference (PD) of absolute value is all arranged during positive polarity and negative polarity, thereby the electrode potential of above-mentioned relative substrate is set.
16. liquid crystal indicator according to claim 15 is characterized in that, also possesses the adjustment part in order to the electrode potential of adjusting the above-mentioned relative substrate that above-mentioned comparative electrode drive division sets.
17. liquid crystal indicator according to claim 16 is characterized in that, above-mentioned liquid crystal indicator moves in electric field controls birefringence pattern.
18. according to claim 10 any described liquid crystal indicator to the claim 17, it is characterized in that, drive the comparative electrode drive division of the electrode of relative substrate, this comparative electrode drive division possesses: synchronous with the reversal of poles of the liquid crystal drive current potential that is applied to above-mentioned liquid crystal layer, and make the electrode potential that is applied to relative substrate carry out the comparative electrode driving voltage counter-rotating portion of reversal of poles.
19. the drive unit of a liquid crystal indicator to possess 2 plate bases of the electrode that liquid crystal drive uses respectively on opposite side, clips liquid crystal layer and configuration relatively constitutes, and possesses plurality of pixels, it is characterized in that it possesses:
According to picture signal, output puts on the liquid crystal driving signal handling part of the liquid crystal drive voltage of liquid crystal layer;
Judgement through 2 block diagrams during the above scheduled period, output makes the scheduled period detection unit of reversal of poles control signal of counter-rotating of the polarity of above-mentioned liquid crystal drive voltage; And above-mentioned liquid crystal driving signal handling part possesses:
According to above-mentioned reversal of poles control signal, the polarity handling part of above-mentioned liquid crystal driving signal handling part of polarity of above-mentioned liquid crystal drive voltage reverses, in each pixel, the liquid crystal drive voltage that is applied to liquid crystal layer is maintained same polarity with respect to predetermined benchmark, and its during keeping be during 2 block diagrams more than.
20. the drive unit of liquid crystal indicator according to claim 19, it is characterized in that, above-mentioned scheduled period detection unit judges through during more than 10 seconds, and above-mentioned liquid crystal driving signal handling part during more than 10 seconds in, above-mentioned liquid crystal drive voltage is maintained same polarity.
21. drive unit according to any described liquid crystal indicator in claim 19 or the claim 20, it is characterized in that, it possesses sequential control portion, the same period signal and preset clock signal of this sequential control portion together to supply with above-mentioned picture signal, generate the clock signal of the actuating signal of the above-mentioned display panels of control, this sequential control portion constitutes above-mentioned scheduled period detection unit, with above-mentioned same period signal serve as that the basis was judged through the scheduled period, generate above-mentioned reverse control signal.
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| JP344999/2003 | 2003-10-02 | ||
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