CN100389357C - LCD device - Google Patents

Abstract

The present invention relates to a liquid crystal display which comprises a plurality of data lines, a plurality of scan lines and a plurality of pixel units, wherein each scan line generates a drive signal, and each data line generates pixel data. Each pixel unit comprises a first switch unit which is used for transmitting the pixel data of the data line when receiving the drive signal of the scan line, a first electrode providing a first voltage signal, a second electrode providing a second voltage signal and a first liquid crystal capacitor of which one pole is electrically connected to the first electrode and the other pole is electrically connected to the first switch unit, a sensing capacitor electrically connected to the first switch unit, a modulation capacitor of which one pole is electrically connected to the second electrode and the other electrode is connected to the second pole of the sensing capacitor and a second liquid crystal capacitor of which one pole is electrically connected to the second pole of the sensing capacitor and the other pole is electrically connected to the first electrode, wherein liquid crystal molecules in the first liquid crystal capacitor are driven according to the pixel data and the first voltage signal, and liquid crystal molecules in the second liquid crystal capacitor are driven by the pixel data, the first voltage signal and the second voltage signal.

Description

LCD

Technical field

The present invention relates to a kind of LCD, refer in particular to a kind of transflective liquid crystal display.

Background technology

(Liquid Crystal Display LCD) generally can be divided into reflective (reflective) LCD, transmission-type (transmissive) LCD and half-transmission half-reflection type (transflective) LCD to LCD.Reflective LCD is meant that light source is entered in the LCD by panel the place ahead, and the reflecting surface (as aluminum metal) via inside reflects to allow the user can watch the display frame of LCD, its advantage is very power saving, but it is relatively poor to can't see the content and the contrast of display screen in darker occasion.Transmission type LCD has a backlight that is arranged at the liquid crystal cells rear usually, and in order to the emitting incident light line, incident ray optionally passes through after the liquid crystal cells, in the display frame of the place ahead of LCD.Transmission type LCD is adapted at using when indoor environment light is dark, but power consumption increases owing to the existence of backlight, and display quality is relatively poor under strong surround lighting.Half-transmission half-reflection type LCD utilizes display reflective and transmission-type display frame simultaneously, when extraneous light is enough, just use external light source, can use backlight when not enough, it is the mode that has power saving and the auxiliary light of tool concurrently, especially is fit to be applied on the electronic product of tool liquid crystal display functions such as mobile phone, personal digital aid (PDA).

Please refer to known technology shown in Figure 1, color liquid crystal display panel 1 has one and presents the pixel cell 10 that two-dimensional array distributes, each pixel cell 10 has included a plurality of sub-pixel unit, be generally and control red (R), green (G), blue (B) trichromatic sub-pixel unit respectively, the trichromatic display effect of this RGB is the result that light produces by colored filter.Fig. 2 is the planimetric map of the pixel cell structure of the traditional half reflection and half transmission formula LCD of expression, and Fig. 3 A and Fig. 3 B have then represented the sectional view of its pixel cell structure.As shown in Figure 2, a pixel cell can be divided into three sub-pixel unit 12R, 12G and 12B, and each sub-pixel unit all is divided into regional transmission (TA) and reflector space (RA).Please refer to shown in Fig. 3 A, at regional transmission (TA), the light (shown in arrow) that comes from backlight passes infrabasal plate 30 and arrives regional transmission (TA), and passes liquid crystal layer (liquid crystal layer), colored filter R and upper substrate 20 successively; At reflector space (TB), the light (shown in arrow) that enters reflector space (TB) need pass a upper substrate 20, colored filter R and liquid crystal layer earlier before reflecting via reflection horizon or electrode 52.Certainly, the partial reflection zone can be selected to be hidden by an achromaticity optical filter (NCF), shown in Fig. 3 B.

Shown in known technology, be the optical characteristics of control LCD, each pixel cell setting comprises element layer 50 and one or two electrode layer.For instance, be formed on the element layer 50 transparency electrode 54 can be formed at the common control of common electrode (common electrode) 22 on the upper substrate 20 and be positioned at the optical characteristics of the liquid crystal layer of regional transmission (TA).Similarly, the optical characteristics that is positioned at the liquid crystal layer of reflector space (TB) is controlled jointly by reflecting electrode 52 and common electrode 22.Common electrode 22 is connected on the bridging line (not shown).Element layer 50 is to be deposited on the infrabasal plate 30, and it mainly includes sweep trace 31 and 32, data line 21-24 (as shown in Figure 2), transistor and protective seam (not shown).Furthermore, also can be formed with memory capacitance usually on element layer 50, after the signal pulse on the sweep trace was scanned, this memory capacitance can be used for keeping the electric charge on the sub-pixel unit.(m, equivalent electrical circuit n) can be with reference to shown in Figure 4 to have the typical sub-pixel unit of regional transmission and reflector space.In Fig. 4, C _LC1Mainly be meant the electric capacity of the liquid crystal layer between transparency electrode 54 and common electrode 22, C _LC2Mainly be meant the electric capacity of the liquid crystal layer between reflecting electrode 52 and common electrode 22, C ₁Be meant memory capacitance, COM then is meant bridging line.

In known technology, display panels also has a quarter wave plate (quarter-wave plate) and a Polarizer (polarizer).

The pixel of traditional half reflection and half transmission formula LCD generally can include transmission area and echo area.The mean gap of supposing transmission area is dt, and the mean gap of echo area is dr, and the subject matter when dr＞1/2dt is: the transmissivity of regional transmission and the reflectivity of reflector space can not reach peak value separately during in same operational voltage value simultaneously.As shown in Figure 5, with dr=dt is example, and it is the 2.8V place that the peak value of V-R curve (reflectance curve) appears at voltage, and it is the 3.7-5V place that the flat area of the peak value of V-T curve (transmittance graph) then appears at voltage, that is when transmissivity reached its high value, reflectivity was inversion state on the contrary.

In known technology, the inverted problem of this reflectivity can be improved via the design of control gap dr, dt accurately, wherein roughly is half of crack between the regional transmission in crack between the reflector space.Yet,, in fact be difficult to reach desired effect owing to processing procedure is complicated though the double gap design is effectively in theory.Industry also attempts going to improve the inverted problem of reflectivity with additive method; For example, be positioned at the magnitude of voltage on regional transmission and the reflector space and utilize insulation course to be coated with methods such as reflecting electrode by control.In detail, the magnitude of voltage of reflector space can reduce by an electric capacity with respect to the magnitude of voltage of regional transmission; As shown in Figure 6, with an independent capacitance C _CBe connected serially to liquid crystal capacitance C _LC2On, reflecting electrode can be expressed as with respect to the magnitude of voltage of bridging line by this:

$V_{\mathrm{<figure-callout\; id="2"\; label="CLC"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">CLC</figure-callout>}2}=V_{\mathrm{CC}}-V_{\mathrm{COM}}=\frac{\mathrm{Cc}}{\mathrm{Cc}+C_{\mathrm{LC}2}}(\mathrm{Vdata}-V_{\mathrm{COM}})$

See also Fig. 7 A and Fig. 7 B.Fig. 7 A is known pixel data V _DataWith the reflective liquid crystal capacitor C _LC2Folder potential difference V _CLC2Graph of a relation, Fig. 7 B is known transparent liquid crystal capacitor C _LC1With the reflective liquid crystal capacitor C _LC2When different operating voltage and the graph of a relation of transmissivity and reflectivity, wherein the longitudinal axis is represented transmissivity and reflectivity, transverse axis remarked pixel data V _DataWith common voltage V _COMVoltage difference.Can observe from Fig. 7 B, when the folder potential difference reached 3V, transmitted intensity (transmissivity) almost reached maximal value, and intensity of light reflection (reflectivity) then approximates 0.2.Though when the folder potential difference reached 4V, transmissivity and reflectivity all rose to maximal value, when the folder potential difference was 5V, reflectivity dropped to 0.6 again.In other words, when the folder potential difference is big (when just pixel data is high gray scale), (shown in the scope A of Fig. 7 B) is narrower for the half cycles of reflectance curve, and the voltage adaptable degree of peak value is less and wayward.Similarly, according to Gamma curve shown in Fig. 7 C, when the 45th rank signal, transmissivity almost reaches 0.5, but reflectivity but no better than 0.In other words, transmitted light is inequality through brightness after the transparent liquid crystal unit and reflected light through the brightness after the reflective liquid crystal unit, and promptly when same operational voltage value, transmitted light and catoptrical transmittance are inequality, and rate of gray level is also different.

Because the problem that above-mentioned known technology ran into is necessary half reflection semi-transmission-type LCD is further improved, to improve its display quality in fact.

Summary of the invention

Fundamental purpose of the present invention is to provide a kind of transflective liquid crystal display, and its reflected light is coordinated mutually with the penetrating light intensity of transmitted light, and can improve display quality.

According to above-mentioned purpose of the present invention, the invention provides a kind of transflective liquid crystal display, it comprises many data lines, multi-strip scanning line, and a plurality of pixel cell, this multi-strip scanning line is used for producing drive signal, and these many data lines are used for producing pixel data.Each pixel cell comprises one first switch element, is used for transmitting the pixel data of a data line when receiving the drive signal of one scan line; One first electrode is used to provide one first voltage signal; One second electrode is used to provide one second voltage signal; One first liquid crystal capacitance (first control capacitor), the one utmost point is electrically connected to this first electrode, and another utmost point is electrically connected to this first switch element, is used for driving liquid crystal molecule in it according to this pixel data and this first voltage signal; One sensing capacitance (sensing capacitor) comprises one first utmost point and one second utmost point, and this first utmost point is electrically connected to this first switch element; One modulating capacitor, the one utmost point are electrically connected to this second electrode, and another utmost point is connected to second utmost point of this sensing capacitance (sensing capacitor); And one second liquid crystal capacitance, the one utmost point is electrically connected to second utmost point of this sensing capacitance (sensing capacitor), another utmost point is electrically connected to this first electrode, is used for driving liquid crystal molecule in it according to this pixel data, this first voltage signal and this second voltage signal.

Description of drawings

Fig. 1 presents the color liquid crystal display panel of the pixel cell of two-dimensional array distribution for expression.

Fig. 2 is the planimetric map of the pixel cell structure of the known half reflection and half transmission formula LCD of expression.

Fig. 3 A and 3B are the sectional view of remarked pixel cellular construction.

Fig. 4 is the equivalent circuit diagram of known pixel unit.

Fig. 5 is transmissivity and the reflectivity of reflector space and the graph of a relation of operating voltage of the regional transmission of known single gap half reflection and half transmission formula LCD.

Fig. 6 is the pixel equivalent circuit figure of the transflective liquid crystal display of known single gap.

Fig. 7 A is known pixel data Vdata, voltage signal V _COMWith the reflective liquid crystal capacitor C _LC2Folder potential difference V _CLC2Graph of a relation.

Fig. 7 B is known transparent liquid crystal capacitor C _LC1, voltage signal V _COMWith the reflective liquid crystal capacitor C _LC2When different operating voltage and the graph of a relation of transmissivity and reflectivity.

Fig. 7 C be known Gamma2.2 curve when the signal distributions on 64 rank, the graph of a relation of transmissivity and reflectivity.

Fig. 8 is the equivalent circuit diagram of the pixel cell of transflective liquid crystal display of the present invention.

Fig. 9 is the section of structure of pixel cell of the present invention.

When Figure 10 works for pixel cell, put on the sequential chart of the voltage of reflective liquid crystal electric capacity before and after pixel data voltage, second voltage signal and the adjustment.

Figure 11 A is pixel data Vdata of the present invention, the first voltage signal V _COM1With the reflective liquid crystal capacitor C _LC2Folder potential difference V _CLC2Graph of a relation.

Figure 11 B is the penetrating light intensity of the reflected light of transflective liquid crystal display of the present invention and the transmitted light curve map with the operating voltage variation.

Figure 12 for Gamma2.2 curve of the present invention when the signal distributions on 64 rank, the graph of a relation of transmissivity and reflectivity.

Figure 13 is pixel cell of the present invention and the equivalent circuit diagram that drives the switch element of second voltage signal.

Figure 14 is the equivalent circuit diagram of second embodiment of the pixel cell of transflective liquid crystal display of the present invention.

The main element symbol description

Pixel cell 100,200 transparent liquid crystal capacitor C _LC1

The reflective liquid crystal capacitor C _LC2Sensing capacitance (sensing capacitor) Cc

Modulating capacitor C ₂Memory capacitance C _ST1, C _ST2

The first electrode COM1, the second electrode COM2

Sweep trace n _Th-gate line data line m _Th-data line

Electric capacity of voltage regulation n _Th-Ccom node 102,104,106

Switch element m _Th-SW, n _Th-SW voltage source 110

Embodiment

See also Fig. 8 and Fig. 9, Fig. 8 is the equivalent circuit diagram of pixel cell 100 of the present invention.Form pixel cell 100 between multi-strip scanning line (gate line) and many data lines (data line) are staggered, Fig. 9 is the section of structure of pixel cell 100.Be formed with first liquid crystal capacitance and one second liquid crystal capacitance in each pixel cell 100, two liquid crystal capacitances are to include a liquid crystal layer between two electrodes to form.The two poles of the earth of first liquid crystal capacitance are all formed by transparency electrode, and a utmost point of second liquid crystal capacitance comprises an electrode with high reflectance and forms, and another utmost point then is a transparency electrode.In the present embodiment, first liquid crystal capacitance is the transparent liquid crystal capacitor C _LC1, it is used for controlling the rotation direction of liquid crystal molecule in the transmission area of transflective displays.Second liquid crystal capacitance is the reflective liquid crystal capacitor C _LC2, it is used for controlling the rotation direction of liquid crystal molecule in the echo area of transflective displays.The transparent liquid crystal capacitor C _LC1A utmost point connect by a switch element mth-SW, (switch element is realized with the film liquid crystal in the present embodiment), another utmost point then is connected with the first electrode COM1; The reflective liquid crystal capacitor C _LC2A utmost point be connected with the first electrode COM1, another utmost point then is connected to the utmost point of a sensing capacitance (sensing capacitor) Cc, and also is connected to modulating capacitor C simultaneously ₂A utmost point, another utmost point of sensing capacitance (sensing capacitor) Cc is by switch element m _Th-SW and data line m _Th-data line is connected, and modulating capacitor C ₂Another utmost point then be connected with the second electrode COM2.In addition, a memory capacitance C can also be set _ST1Be used for reducing the interference of extraneous noise, this memory capacitance C _ST1With the transparent liquid crystal capacitor C _LC1Parallel connection, the one utmost point is connected with switch element, and another utmost point links to each other with third electrode COM3, and wherein COM1 and COM3 can be same current potential, also can be different potentials.

See also Figure 10, during 100 work of Figure 10 pixel cell, pixel data voltage Vdata, the first voltage signal V _COM1, the second voltage signal V _COM2And the sequential chart that puts on the voltage vcc of reflective liquid crystal electric capacity before and after adjusting, dotted line is a datum among the figure.When being scanned up to n bar sweep trace (n _Th-gate line) time, sweep trace n _Th-gate line can send the one scan signal so that switch element m _Th-SW conducting, at this moment, pixel data Vdata is via data line m _Th-data line is by switch element m _Th-SW is sent to node 102.At this moment, transparent liquid crystal capacitor C _LC1Folder potential difference V _CLC1Be the voltage difference of the pixel data voltage Vdata and the first voltage signal COM1, and the reflective liquid crystal capacitor C _LC2Folder potential difference V _CLC2Then can be subjected to sensing capacitance (sensing capacitor) Cc and modulating capacitor C ₂Influence, make folder potential difference V _CLC2Not only with the pixel data voltage Vdata and the first voltage signal V _COM1Relevant, also be subjected to the second voltage signal V simultaneously _COM2Influence.According to Kirchhoff current law (Kirchhoff ' s Current Law), the net current of node 104 is:

$\frac{(\mathrm{Vcc}-\mathrm{Vdata})}{\frac{1}{\mathrm{SCc}}}+\frac{\mathrm{Vcc}-{\mathrm{<figure-callout\; id="1"\; label="V\; COM"\; filenames="C20061007467200141.png,C20061007467200152.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{COM}}}{\frac{1}{{\mathrm{SC}}_{\mathrm{LC}2}}}+\frac{\mathrm{Vcc}-{\mathrm{<figure-callout\; id="2"\; label="V\; COM"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{COM}}}{\frac{1}{{\mathrm{<figure-callout\; id="2"\; label="SC"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">SC</figure-callout>}}_2}}=0$

Wherein the voltage of node 104 is Vcc, and S is the frequency response parameter.

Therefore, the voltage of node 104 $\mathrm{Vcc}=\frac{\mathrm{Cc}\&CenterDot;\mathrm{Vdata}+{\mathrm{<figure-callout\; id="2"\; label="C\; LC"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{LC}}\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="V\; COM"\; filenames="C20061007467200141.png,C20061007467200152.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{COM}}+{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">C</figure-callout>}}_2\&CenterDot;V_{\mathrm{COM}2}}{{\mathrm{<figure-callout\; id="2"\; label="C\; LC"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{LC}}+\mathrm{Cc}+{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">C</figure-callout>}}_2},$

So reflective liquid crystal capacitor C _LC2The folder potential difference

$\left|{\mathrm{<figure-callout\; id="2"\; label="V\; CLC"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{CLC}}\right|=|\mathrm{Vcc}-{\mathrm{<figure-callout\; id="1"\; label="V\; COM"\; filenames="C20061007467200141.png,C20061007467200152.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{COM}}|=|\frac{\mathrm{<figure-callout\; id="2"\; label="Cc\; C\; LC"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">Cc</figure-callout>}}{C_{\mathrm{LC}}}\&times;(V_{\mathrm{data}}-V_{\mathrm{COM}1})+\frac{C_2}{{\mathrm{<figure-callout\; id="2"\; label="C\; LC"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{LC}}+C_C+{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="C20061007467200151.png,C20061007467200162.png"\; state="\{\{state\}\}">C</figure-callout>}}_2}\&times;(V_{\mathrm{COM}2}-V_{\mathrm{COM}1})|$

Compared to known technology, the reflective liquid crystal capacitor C _LC2Folder potential difference V _CLC2After greater than a certain value, can be under same pixel data voltage Vdata because the second voltage signal V _COM2Effect and become smaller.

See also Figure 11 A, Figure 11 B and Figure 12, Figure 11 A is pixel data Vdata of the present invention and reflective liquid crystal capacitor C _LC2Folder potential difference V _CLC2Graph of a relation.Figure 11 B is the reflected light of transflective liquid crystal display of the present invention and the transmittance graph and the reflectance curve synoptic diagram of transmitted light, the voltage difference of the transverse axis remarked pixel data voltage and first voltage signal among the figure, and the longitudinal axis is represented transmissivity and reflectivity.By Figure 11 B as can be known, the curve of transmission and reflection is preceding very identical in about 4.3V's, also can both reach almost the highest efficient in 4.3V.As shown in figure 12, the grey scale change curve of transmission and reflection is quite coordinated, and can significantly improve display quality.In Figure 11 A, Figure 11 B and Figure 12, at the second voltage signal amplitude V _COM2=0.5V, C _C/ (C _C+ C _LC2+ C ₂)=0.46, C ₂/ (C _C+ C _LC2+ C ₂Under the condition of)=0.32, the reflected light of the transflective liquid crystal display of present embodiment and the penetrating light intensity of transmitted light are with operating voltage (that is the pixel data voltage Vdata and the first voltage signal V _COM1Voltage difference) change and to be the consistent state that is similar to.In other words, compare with Fig. 7 A and Fig. 7 B, among Figure 11 B, the maximum transmission intensity of reflected light under same operating voltage and transmitted light almost is to rise to its maximal value simultaneously, and reflective liquid crystal electric capacity almost has the identical threshold voltage (V shown in Figure 11 A with transparent liquid crystal electric capacity _Threshold).In addition, when pixel voltage signal was high gray scale, half cycles of the present invention (the scope B of Figure 11 B) was wider than the half cycles (the scope A shown in Fig. 7 B) of known technology.In other words, in Fig. 7 A, when pixel voltage signal Vdata is big more, the folder potential difference V of reflective liquid crystal electric capacity _CLC2Rate of change is than the rate of change of Figure 11 A also big more (that is the slope of the straight line C of Fig. 7 A is greater than slope of the straight line D of Figure 11 A), reflectance curve no longer is to skyrocket to 1 by 0 in the interval of 2.7V to 4V, but relatively gently by rising to 1 by 0 in the interval of 2V to 4V, so help the planning of pixel voltage level.Generally speaking, design of the present invention has improved the display quality of the transflective liquid crystal display of dr＞1/2dt, thereby solves known transflective liquid crystal display transmission and the inharmonic defective of reflection grey scale change.

Be noted that the second voltage signal V that the second electrode COM2 provides _COM2And modulating capacitor C ₂And the purpose of sensing capacitance (sensing capacitor) Cc is used for making the reflective liquid crystal capacitor C _LC2When receiving pixel voltage signal Vdata, can moderately dwindle acting on the reflective liquid crystal capacitor C _LC2Voltage difference.In Fig. 7, with the second voltage signal V _COM2Amplitude be Simulation result under the 0.5V, the second voltage signal V _COM2The phase place and the first voltage signal V _COM1Phase place opposite, its amplitude is by the decision of the size of C2.As the second voltage signal V _COM2The phase place and the first voltage signal V _COM1Phase place for also to belong to category of the present invention with phase time.In addition, also can be with the second voltage signal V _COM2Be set at certain value.

See also Figure 10 and Figure 12, Figure 12 is pixel cell 100 of the present invention and the driving second voltage signal V _COM2The equivalent circuit diagram of switch element.As sweep trace n _ThDuring-gate line scanning, switch element n _Th-SW, m _Th-SW conducting simultaneously, switch element m _Th-SW can cause pixel data voltage to transfer to node 102, at the same time, and switch element n _ThThe conducting of-SW causes the second voltage signal V _COM2Transfer to the second electrode n by its voltage source 110 _Th-COM2.Electric capacity of voltage regulation n _Th-C _ComBe electrically connected to one the 5th electrode COM5, in case this switch element n _Th-SW turn-offs, and the second corresponding electrode n _Th-COM2 is in floating, and its current potential can pass through electric capacity of voltage regulation n _Th-C _ComInduction and with the first voltage signal V _COM1Potential change.

The switch element n of present embodiment _ThIt is consistent with sweep trace that-SW drives sequential because of it, thus can be arranged among each pixel cell 100, or be arranged on the outside of panel, or be arranged among the gate pole driver (gate driver).

Second embodiment of transflective liquid crystal display of the present invention also can adopt equivalent circuit diagram as shown in figure 14, and pixel cell shown in the figure 200 is different with aforementioned first embodiment is in the reflective liquid crystal capacitor C _LC2A utmost point be connected with the first electrode COM1, another utmost point then is connected to the utmost point of sensing capacitance (sensing capacitor) Cc, and also is connected to modulating capacitor C simultaneously ₂A utmost point and memory capacitance C _ST2A utmost point, this memory capacitance C _ST2Another utmost point be connected on the 4th electrode COM4, wherein COM1, COM3 and COM4 can be same current potential, also can be different potentials.Because in display, metal wire and electrode can overlap each other inevitably and produce sensing capacitance (sensing capacitor) effect, therefore may cause each electric capacity and desired target voltage values that excessive voltage error is arranged, so optionally set up memory capacitance C _ST2Can be used to eliminate sensing capacitance (sensing capacitor) effect.

Compared to prior art, transflective liquid crystal display of the present invention is by being provided with second electrode, sensing capacitance (sensing capacitor) and modulating capacitor, and can modulate the voltage of reflective liquid crystal electric capacity (or transflective liquid crystal electric capacity), thereby make and on reflective liquid crystal electric capacity (or transflective liquid crystal electric capacity), can access desirable folder potential difference, be that reflected light of the present invention is the consistent state that is similar to the penetrating light intensity of transmitted light with the operating voltage variation, the maximum transmission intensity of reflected light under same operating voltage and transmitted light almost is to rise to its maximal value simultaneously, improve the display quality of transflective liquid crystal display of the present invention by this, thereby improve the transmission and the inharmonic defective of reflection grey scale change of known single gap transflective liquid crystal display.

The above person only is a better embodiment of the present invention, and equivalent modifications or variation that those skilled in the art carry out according to spirit of the present invention all are covered by in the accompanying application right claimed range.

Claims (11)

1. LCD comprises:

Many data lines are used for transmitting pixel data;

The multi-strip scanning line is used for transmitting drive signal; And

A plurality of pixel cells, each pixel cell comprises:

One first switch element is used for transmitting the pixel data of a data line when receiving the drive signal of one scan line;

One first electrode is used to provide one first voltage signal;

One second electrode is used to provide one second voltage signal;

One first liquid crystal capacitance, the one utmost point are electrically connected to this first electrode, and another utmost point is electrically connected to this first switch element, are used for driving liquid crystal molecule in it according to this pixel data and this first voltage signal;

One sensing capacitance comprises one first utmost point and one second utmost point, and this first utmost point is electrically connected to this first switch element;

One modulating capacitor, the one utmost point are electrically connected to this second electrode, and another utmost point is connected to second utmost point of this sensing capacitance; And

One second liquid crystal capacitance, the one utmost point are electrically connected to second utmost point of this sensing capacitance, and another utmost point is electrically connected to this first electrode, are used for driving liquid crystal molecule in it according to this pixel data, this first voltage signal and this second voltage signal.

2. LCD as claimed in claim 1, it also comprises one first memory capacitance, and the one utmost point is electrically connected to this first switch element, and another utmost point is electrically connected to a third electrode, and this third electrode is used to provide a tertiary voltage signal.

3. LCD as claimed in claim 1, it also comprises one second memory capacitance, and the one utmost point is electrically connected to second utmost point of this sensing capacitance, and another utmost point is electrically connected to one the 4th electrode, and the 4th electrode is used to provide one the 4th voltage signal.

4. as the described LCD of one of claim 1 to 3, wherein the two ends of this first liquid crystal capacitance are respectively formed by transparency electrode, and a utmost point of this second liquid crystal capacitance is formed by an electrode with high reflectance, and another utmost point is then formed by transparency electrode.

5. as claim 1,2 or 3 described LCD, it also comprises:

One voltage source is used for producing the voltage signal of this second electrode; And

One second switch unit, a utmost point is connected to this voltage source, and another utmost point is connected to this second electrode, and when this second switch unit was used for receiving the drive signal of this sweep trace, this second voltage signal was transferred to this second electrode.

6. LCD as claimed in claim 5, it also comprises an electric capacity of voltage regulation, and the one utmost point is electrically connected to one the 5th electrode, and another utmost point is electrically connected to this second switch unit, is used to stablize this second voltage signal.

7. as claim 1,2 or 3 described LCD, this first voltage signal and this second voltage signal are AC signal.

8. LCD as claimed in claim 7, wherein this first voltage signal and this second voltage signal homophase.

9. LCD as claimed in claim 7, wherein this first voltage signal and this second voltage signal are anti-phase each other.

10. as claim 1,2 or 3 described LCD, wherein this first voltage signal is a direct current signal.

11. as claim 1,2 or 3 described LCD, wherein this second voltage signal is a direct current signal.

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