JP4821698B2 - Driving method of reflection type liquid crystal device - Google Patents

Description

  The present invention relates to a reflective liquid crystal device and an electronic apparatus, and more particularly to a reflective liquid crystal device to which a lateral electric field mode is applied.

  A projection type liquid crystal display device using a reflection mode liquid crystal display system has been known. One configuration example of this type of projection type liquid crystal display device is shown in FIG. The projection type liquid crystal display device of this example includes a light source 101, a lens 102 that converts light emitted from the light source 101 into parallel light, a polarization beam splitter 103 that reflects one polarized light and transmits the other polarized light. It has a color separation / synthesis system composed of optical members such as a dichroic prism 104 that separates and combines light into three primary colors of red (R), green (G), and blue (B). Then, three reflection mode liquid crystal light valves 105R, 105G, which reflect the light of the three primary colors separated by the color separation / synthesis system as incident light and control the reflectance according to the image signals of the respective colors. 105B and a projection lens 107 that combines the reflected light again with a color separation / synthesis system and enlarges and projects it onto the screen 106.

  FIG. 17 shows a configuration example of a reflection mode liquid crystal light valve. As shown in this figure, a frame-shaped sealing material 112 is sandwiched between two transparent substrates of an element substrate 110 and a counter substrate 111, and the liquid crystal 113 is sealed. The liquid crystal 113 aligns liquid crystal molecules substantially vertically when no voltage is applied, and uses a material having negative dielectric anisotropy to incline the liquid crystal molecules horizontally when a voltage is applied (hereinafter referred to as a vertical alignment mode). Is. On the upper surface of the element substrate 110, a plurality of reflective electrodes 114 serving both as reflective films and pixel electrodes are arranged. For example, if the element substrate 110 is an active matrix substrate using thin film transistors (hereinafter abbreviated as TFTs) as switching elements, a large number of reflective electrodes 114 are arranged in a matrix, and each reflective electrode 114 is Data lines (not shown) and scanning lines (not shown) arranged in a grid are connected via TFTs (not shown). The reflective electrode 114 is usually formed of a metal such as silver or aluminum, and the surface thereof is a reflective surface that reflects light incident from the counter substrate 111 side. An alignment film 115 is provided on the reflective electrode 114. On the other hand, on the counter substrate 111, a light shielding film 116 is provided in a region between adjacent reflective electrodes 114, an insulating film 117 covering the light shielding film 116 is provided, and indium tin oxide (Indium Tin oxide) is provided on the insulating film 117. A counter electrode 118 made of a transparent conductive film such as Oxide (hereinafter abbreviated as ITO) is provided. An alignment film 119 is provided on the counter electrode 118. Further, a retardation plate 120 and a polarizing plate 121 are provided outside the counter substrate 111.

  However, the reflection type liquid crystal light valve having the above configuration has the following problems.

  Conventionally, vertical alignment mode liquid crystals have been studied for reflective liquid crystal light valves. The reason is that in the vertical alignment mode, the liquid crystal molecules are aligned vertically to the substrate surface (there is no optical retardation as viewed from the normal direction) as black display, so the black display has good image quality. High contrast can be obtained. In addition, in the TN liquid crystal in the vertical alignment mode having excellent front contrast, the viewing angle range in which a constant contrast can be obtained is wider than that in the twisted nematic (hereinafter abbreviated as TN) liquid crystal in the horizontal alignment mode. Further, since a twist structure is not used for the liquid crystal layer as compared with the TN method, various effects such as a high response speed can be expected.

  Although it is a vertical alignment mode having such advantages, on the other hand, when applied to a reflective liquid crystal light valve, the occurrence of disclination (liquid crystal alignment failure) is unavoidable, and in fact it is bright and has a high contrast. It was difficult to obtain a high reflection type liquid crystal light valve.

  FIG. 18 shows the result of simulating the electric field applied to the liquid crystal and the transmittance of light in the vertical alignment mode reflective liquid crystal display device. In the figure, reference numeral 130 is a pixel electrode (reflection electrode), 131 is a counter electrode, a curve E indicated by a one-dot chain line is an equipotential line, and a curve T indicated by a solid line is a transmittance curve. In addition, a voltage of + 5V with respect to the common electrode for one pixel electrode (hereinafter, the voltage of the pixel electrode is set with respect to the common electrode, and the voltage of the common electrode is set with respect to the central voltage of the voltage width applied to the liquid crystal Is applied to the adjacent pixel electrode, such as dot inversion driving, line inversion driving, etc. in which a reverse polarity voltage is applied to the adjacent pixel electrode. The driving method shall be adopted. In this example, since the liquid crystal in the vertical alignment mode is used, the liquid crystal molecules are inclined in a direction along the equipotential line.

  When attention is paid to one pixel region R, disclination occurs in the center of the pixel region R, and the disk is also formed at the end of the pixel region R due to the influence of an electric field applied to the adjacent pixel electrode. Occurrence of association is observed. Since a driving method such as dot inversion driving is employed, a bright and high-contrast display cannot be expected unless the disclination at the center of the pixel area and the disclination at the edge of the pixel area are suppressed.

  As described above, the case of the vertical alignment mode has been described as an example. However, even when the TN liquid crystal in the horizontal alignment mode is used, there are exactly the same problems.

  The present invention has been made to solve the above-described problem, and a reflective liquid crystal device capable of suppressing a disclination due to the influence of an electric field of an adjacent pixel and obtaining a bright and high-contrast display, and the same. The purpose is to provide electronic devices.

In order to solve the above-described problems, a driving method of a reflective liquid crystal device according to the present invention includes a liquid crystal sandwiched between a pair of substrates including an element substrate and a counter substrate, and a plurality of pixels formed in a matrix. and, have rows reflective display by adding transverse electric field to the liquid crystal in a display region formed by said plurality of pixels, each of the plurality of pixels constituting the rectangle in plan view along the periphery of the rectangular An I-shaped pixel electrode comprising a formed frame-shaped common electrode, two line segments that overlap two opposite sides of the common electrode, and a line segment that connects substantially the centers of the two line segments; A switching element provided at a corner of the common electrode, and a reflective electrode formed on the element substrate so as to cover the display region in the cross-sectional direction of the pixel, the common electrode, and the pixel The electrode In order, are connected through an insulating film, wherein the upper common electrode, a driving method of a reflection-type liquid crystal device is an auxiliary common electrode is provided via an insulating film, in a predetermined said pixel electrode applies a first voltage is a positive voltage, the said pixel electrodes next, driven by a plurality of the switching elements to apply a second voltage which is opposite in polarity to the voltage of the first voltage, wherein the common electrode, wherein the third voltage is applied with the intermediate potential between the first voltage and the second voltage, wherein the auxiliary common electrode at the first voltage and the reverse polarity, lower than the third voltage and applying a fourth potential is a voltage potential.

According to this configuration, the influence of the applied electric field from the adjacent pixel can be reduced by applying the horizontal electric field mode, and in particular, the disclination at the end of the pixel region can be sufficiently suppressed.
  Therefore, it is possible to realize a reflective liquid crystal device that can display brighter and higher contrast than conventional ones.

According to the reflective liquid crystal device of the present invention, it is preferable that the counter-side common electrode is formed at a position overlapping the counter electrode on the counter substrate, and the third voltage is applied.
Further, an auxiliary common electrode is further provided above the common electrode on the element substrate via an insulating film, and a fourth potential having the same polarity as the first voltage and a higher potential than the third voltage is provided. Preferably it is applied .
To solve the above SL problems, an electronic apparatus of the present invention is characterized by comprising a reflection type liquid crystal device of the described.

  As the positional relationship between the common electrode and the pixel electrode, the common electrode can be provided at both ends of each pixel region, and the pixel electrode can be provided at the center of each pixel region above the common electrode with an insulating film interposed therebetween.

  In that case, a counter-side common electrode can be provided on the counter substrate. 0 V may be applied to the counter-side common electrode, or a voltage having a polarity opposite to that of the pixel electrode on the element substrate may be applied.

  In addition, regarding the width of the common electrode and the pixel electrode, the width of the common electrode and the pixel electrode may be made as thin as the width of the data line and the scanning line, or the common electrode and the pixel electrode may be formed in one pixel region. It may be formed wide enough to cover the inside.

  Furthermore, an auxiliary common electrode may be provided above the common electrode arranged at the end of each pixel region. Usually, 0 V is applied to the common electrode, but a slight voltage close to 0 V (for example, about 1 V) is applied to the auxiliary common electrode. As for the polarity of the applied voltage, a voltage having the same polarity as that applied to the pixel electrode may be applied, or a voltage having a polarity opposite to that applied to the pixel electrode may be applied.

  As another positional relationship between the common electrode and the pixel electrode, contrary to the above case, the pixel electrode is provided at both ends of each pixel region, and the common electrode is provided in each pixel region on the upper layer of the pixel electrode through the insulating film. You may provide in a center part.

  As another positional relationship, a common electrode may be provided at both ends of each pixel region, and the pixel electrode may be provided on the same layer as the common electrode and insulated from the common electrode, and provided at the center of each pixel region. Good.

  Instead of forming the reflective layer with the conductive material as described above, a so-called dielectric mirror may be formed by using a dielectric material, and a voltage may not be applied to the reflective layer.

  Although various electrode configuration variations have been presented above, in all of these cases, the influence of the applied electric field from adjacent pixels can be reduced as compared to the conventional case. The simulation results for each electrode configuration will be described in detail in the following “Embodiments of the Invention” section.

[First Reference Form]
A first reference embodiment will be described below with reference to FIGS.

FIG. 1 is a plan view of two adjacent pixels in a TFT array substrate (element substrate) constituting the reflective liquid crystal display device of this embodiment , and FIG. 2 is a cross section taken along the line AA ′ of FIG. FIG. In FIG. 2, the scales are different for each layer and each member so that each layer and each member can be recognized in the drawing.

On the TFT array substrate 1 of the reflective liquid crystal device, as shown in FIG. 1, data lines 2 extending in the vertical direction on the paper surface and scanning lines 3 extending in the horizontal direction on the paper surface are provided in a grid pattern. A TFT 5 is provided at a corner of each pixel region R partitioned by the data line 2 and the scanning line 3. In the case of the present embodiment , the TFT 5 is a bottom gate type TFT as shown in FIG. 2, the semiconductor layer 7 crosses over the gate electrode 6 extending from the scanning line 3, and the data line 2 is connected to one end of the semiconductor layer 7. (Corresponding to the source electrode in TFT 5) is connected, and the pixel electrode 8 (corresponding to the drain electrode in TFT 5) is connected to the other end of the semiconductor layer 7. A frame-shaped common electrode 9 is formed along the peripheral edge of the pixel region R, while the pixel electrode 8 extends in the center of the pixel region R. Therefore, in this TFT array substrate 1, a voltage is applied between the common electrode 9 and the pixel electrode 8.
Is applied, a horizontal electric field (arrow B) is generated between the two sides of the common electrode 9 extending in the vertical direction on the paper surface at the end of the pixel region R and the pixel electrode 8 at the center of the pixel region R. Yes.

Sectional structure of a reflective liquid crystal device according to this reference embodiment, as shown in FIG. 2, has a pair of transparent substrates 10 and 11, the TFT array substrate 1 and forming a one substrate, opposed thereto And a counter substrate 12 that forms the other substrate, and a horizontal alignment mode liquid crystal 13 is sandwiched between the substrates 1 and 12.

  A reflective electrode 14 (reflective layer) made of a highly reflective metal film (conductive material) such as aluminum or silver is formed on the entire surface of the transparent substrate 10 constituting the TFT array substrate 1. A first insulating film 15 is formed on the reflective electrode 14, and the scanning line 3, the gate electrode 6, and the common electrode 9 are formed on the first insulating film 15. A second insulating film 16 serving as a gate insulating film of the TFT 5 is formed so as to cover the scanning line 3, the gate electrode 6, and the common electrode 9, and the semiconductor layer 7 is formed on the second insulating film 16. A data line 2 and a pixel electrode 8 are formed so as to be in contact with both ends of the semiconductor layer 7, and a third insulating film 17 is formed so as to cover the entire surface. Although not shown here, an alignment film is formed on the third insulating film 17.

  On the other hand, on the counter substrate 12, a light shielding film 18 that shields a region between adjacent pixel regions R on the transparent substrate 11 is formed, and an alignment film (not shown) is formed on the entire surface.

FIG. 3 shows the result of simulation of the electric field applied to the liquid crystal in the electrode configuration of the present embodiment. In the figure, reference numeral 14 is a reflective electrode, 9 is a common electrode, 8 is a pixel electrode, and a curve E indicated by a solid line is a line of electric force. Further, if a voltage of + 5V is applied to one pixel electrode 8, a voltage having a reverse polarity is applied to the adjacent pixel electrode 8, such that a voltage of -5V is applied to the adjacent pixel electrode 8. A driving method such as dot inversion driving or line inversion driving is adopted. 0 V is applied to the common electrode 9. Moreover, because of the use of liquid crystal according to this reference embodiment the horizontal alignment mode, liquid crystal molecules are inclined in a direction substantially perpendicular to the electric field lines E.

In the case of this reference form , disclination occurs in the center of the pixel region R, but in the vicinity of the end of the pixel region R, the pixel region R is adjacent to the adjacent pixel region R as compared with the conventional example shown in FIG. It is confirmed that the influence of the electric field is small, the electric lines of force E are relatively standing with respect to the substrate surface, the alignment of the liquid crystal molecules is less disturbed, and the occurrence of disclination can be suppressed. Therefore, according to the present embodiment , it is possible to realize a reflective liquid crystal display device that is brighter and has a higher contrast than conventional ones.

[Second Reference Form ]
Hereinafter, the second reference embodiment of the present invention FIG. 4, will be described with reference to FIG.

FIG. 4 is a cross-sectional view of a reflective liquid crystal display device according to this embodiment . The basic structure of the reflective liquid crystal display device of this reference form is the same as that of the first reference form , and the only difference is that the counter-side common electrode is also provided on the counter substrate side. Therefore, in FIG. 4, the same components as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

In the reflective liquid crystal display device of the present embodiment , as shown in FIG. 4, an insulating film 21 covering the light shielding film 18 on the counter substrate 12 is formed, and the common electrode 9 on the TFT array substrate 1 on the insulating film 21 is formed. The counter-side common electrode 22 is formed at a position above the.

FIG. 5 shows the result of simulation of the electric field applied to the liquid crystal in the electrode configuration of the present embodiment. In the figure, reference numeral 14 is a reflective electrode, 9 is a common electrode, 8 is a pixel electrode, 22 is a common electrode on the opposite side, and a curve E indicated by a solid line is an equipotential line . A driving method such as dot inversion driving or line inversion driving in which a reverse polarity voltage is applied to the adjacent pixel electrode 8 is adopted, and 0 V is applied to the counter-side common electrode 22.

Also in the case of the present embodiment, in the vicinity of the end of the pixel region R, the influence of the electric field from the adjacent pixel region R is less than that in the conventional example shown in FIG. It is confirmed that the liquid crystal molecules are less disturbed and the occurrence of disclination can be suppressed. Therefore, according to the present embodiment , it is possible to realize a reflective liquid crystal display device that is brighter and has a higher contrast than conventional ones.

  Although an example in which 0 V is applied to the counter-side common electrode 22 is shown here, a voltage having a polarity opposite to that of the pixel electrode 8 on the TFT array substrate 1 may be applied to the counter-side common electrode 22.

[Third Reference Form ]
Hereinafter, a description will be given of a third reference embodiment of the present invention with reference to FIG.

FIG. 6 shows the result of simulating the electric field applied to the liquid crystal in the electrode configuration of this embodiment. The first, in the form of a second reference, although thinner form the width of the common electrode and the pixel electrode to the width and the same degree of data lines and scanning lines, in the present reference is the common electrode and the pixel electrode This is an example in which the pixel area is formed so wide as to substantially cover the inside of one pixel area.

In FIG. 6, reference numeral 14 is a reflective electrode, 9 is a common electrode, 8 is a pixel electrode, and a curve E indicated by a solid line is a line of electric force. A driving method such as dot inversion driving or line inversion driving in which a reverse polarity voltage is applied between adjacent pixel electrodes 8 is employed.

Also in the case of the present embodiment , the influence of the electric field from the adjacent pixel region R is less in the vicinity of the end of the pixel region R than the conventional example shown in FIG. It is confirmed that the liquid crystal molecules are less disturbed and the occurrence of disclination can be suppressed. Therefore, according to the present embodiment , it is possible to realize a reflective liquid crystal display device that is brighter and has a higher contrast than conventional ones.

[Implementation of the form]
Hereinafter, describing the implementation of the embodiment of the present invention with reference to FIGS.

  FIG. 7 is a cross-sectional view of the reflective liquid crystal display device of this embodiment. The basic structure of the reflective liquid crystal display device of this embodiment is the same as that of the above embodiment, and the only difference is that an auxiliary common electrode is provided on the TFT array substrate. Therefore, in FIG. 7, the same code | symbol is attached | subjected to the same component as FIG. 2, and detailed description is abbreviate | omitted.

  In the reflective liquid crystal display device of the present embodiment, as shown in FIG. 7, two auxiliary common electrodes 24 are formed at positions above the common electrode 9 on the second insulating film 16 of the TFT array substrate 1. ing.

FIG. 8 shows the result of simulation of the electric field applied to the liquid crystal in the electrode configuration of the present embodiment. In the figure, reference numeral 14 is a reflective electrode, 9 is a common electrode, 24 is an auxiliary common electrode, 8 is a pixel electrode, and a curve E indicated by a solid line is an equipotential line . A driving method such as dot inversion driving or line inversion driving in which a voltage having a reverse polarity is applied to the adjacent pixel electrode 8 is adopted. The pixel electrode 8 has + 5V, and the auxiliary common electrode 24 has a voltage having the same polarity as the pixel electrode 8. + 1V is applied.

Also in this embodiment, near the edge of the pixel region R, less affected by the electric field from the adjacent pixel region R as compared with the conventional example shown in FIG. 18, the equipotential line E relative to the substrate surface It is confirmed that the liquid crystal molecules are less disturbed and the occurrence of disclination can be suppressed. Therefore, according to the present embodiment, it is possible to realize a reflective liquid crystal display device that is brighter and higher in contrast than conventional ones.

  FIG. 9 is a simulation result when −1 V, which is a voltage having a polarity opposite to that of the pixel electrode 8, is applied to the auxiliary common electrode 24 in contrast to FIG. 8 in which +1 V is applied to the auxiliary common electrode 24. In the case of FIG. 9 as well, almost the same result as in FIG. 8 is shown, and the occurrence of disclination can be suppressed.

[ Fourth Reference Form ]
Hereinafter, a description will be given of a fourth reference embodiment of the present invention with reference to FIG. 10.

FIG. 10 shows the result of simulation of the electric field applied to the liquid crystal in the electrode configuration of this embodiment. In the above reference form , the common electrode and the pixel electrode are positioned on the lower layer side and the pixel electrode on the upper layer side, whereas in this reference form, the common electrode is on the upper layer side and the pixel electrode is on the lower layer side. It is an example.

In FIG. 10, reference numeral 14 is a reflective electrode, 9 is a common electrode, 8 is a pixel electrode, and a curve E indicated by a solid line is an equipotential line . A driving method such as dot inversion driving or line inversion driving in which a reverse polarity voltage is applied to the adjacent pixel electrode 8 is employed.

Also in the case of this reference mode , the positional relationship between the common electrode 9 and the pixel electrode 8 is the same as the result of the first reference mode (see FIG. 3) which is reversed. Compared to the conventional example shown, the influence of the electric field from the adjacent pixel region E is less, the electric lines of force E are relatively standing with respect to the substrate surface, the liquid crystal molecules are less disturbed, and disclination It is confirmed that the generation can be suppressed. Therefore, according to the present embodiment , it is possible to realize a reflective liquid crystal display device that is brighter and has a higher contrast than conventional ones.

[ Fifth Reference Form ]
Hereinafter, a description will be given of a fifth reference embodiment of the present invention with reference to FIG. 11.

FIG. 11 shows the result of simulation of the electric field applied to the liquid crystal in the electrode configuration of this embodiment. This embodiment is an example in which the common electrode and the pixel electrode are provided on the same layer as the positional relationship between the common electrode and the pixel electrode.

In FIG. 11, reference numeral 14 is a reflective electrode, 9 is a common electrode, 8 is a pixel electrode, and a curve indicated by a solid line is an equipotential line . A driving method such as dot inversion driving or line inversion driving in which a reverse polarity voltage is applied between adjacent pixel electrodes 8 is employed.

Also in the case of the present embodiment , the influence of the electric field from the adjacent pixel region R is less in the vicinity of the end of the pixel region R than the conventional example shown in FIG. It is confirmed that the liquid crystal molecules are less disturbed and the occurrence of disclination can be suppressed. Therefore, according to the present embodiment , it is possible to realize a reflective liquid crystal display device that is brighter and has a higher contrast than conventional ones.

[ Sixth Reference Form ]
Hereinafter, a sixth reference embodiment of the present invention will be described with reference to FIG.

FIG. 12 shows a simulation of the electric field applied to the liquid crystal in the electrode configuration of this embodiment.
The result of having performed is shown. In all of the embodiments and the first to fifth reference forms, the reflective layer was formed of a conductive material and used as a reflective electrode, whereas in the present reference form , the reflective layer was formed of a dielectric material, This is an example when no voltage is applied.

In FIG. 12, reference numeral 9 is a common electrode, 8 is a pixel electrode, and a curve E indicated by a solid line is an equipotential line . The reflective layer is made of a dielectric material and constitutes a so-called dielectric mirror. However, this only functions as a reflective layer and no voltage is applied, and thus it is not shown in FIG. In addition, a driving method such as dot inversion driving or line inversion driving in which a voltage having a reverse polarity is applied to the adjacent pixel electrode 8 is employed.

Also in the case of the present embodiment , the influence of the electric field from the adjacent pixel region R is less in the vicinity of the end of the pixel region R than the conventional example shown in FIG. It is confirmed that the liquid crystal molecules are less disturbed and the occurrence of disclination can be suppressed. Therefore, according to the present embodiment , it is possible to realize a reflective liquid crystal display device that is brighter and has a higher contrast than conventional ones. In particular, in the case of this reference form , it is estimated that the influence of the electric field from the adjacent pixel region is the least in the above reference form .

[Example of electronic equipment]
Hereinafter, specific examples of the electronic apparatus including the reflective liquid crystal device of the present invention will be described.

  FIG. 13 is a perspective view showing an example of a mobile phone.

  In FIG. 13, reference numeral 1000 denotes a mobile phone body, and reference numeral 1001 denotes a liquid crystal display unit using the liquid crystal device.

  FIG. 14 is a perspective view showing an example of a wristwatch type electronic device.

  In FIG. 14, reference numeral 1100 denotes a watch body, and reference numeral 1101 denotes a liquid crystal display unit using the above liquid crystal device.

  FIG. 15 is a perspective view illustrating an example of a portable information processing apparatus such as a word processor or a personal computer.

  In FIG. 15, reference numeral 1200 denotes an information processing apparatus, reference numeral 1202 denotes an input unit such as a keyboard, reference numeral 1204 denotes an information processing apparatus main body, and reference numeral 1206 denotes a liquid crystal display unit using the liquid crystal device.

  Since the electronic apparatus shown in FIGS. 13 to 15 includes a liquid crystal display unit using the above-described reflective liquid crystal device, an electronic apparatus including a bright and high-contrast display unit can be realized.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the planar arrangement and dimensions of the common electrode and the pixel electrode that generate a lateral electric field can be arbitrarily designed.

  As described above in detail, according to the present invention, the influence of the electric field from the adjacent pixel can be sufficiently reduced by applying the horizontal electric field mode, and the disclination at the end of the pixel region can be suppressed. It is possible to realize a reflective liquid crystal device capable of obtaining a bright and high contrast display.

It is a plan view of a pixel of a TFT array substrate constituting the reflection type liquid crystal display device of the first reference embodiment. It is sectional drawing which follows the AA 'line of FIG. It is a simulation result of the electric field applied to the liquid crystal in the electrode configuration of the reference embodiment. It is sectional drawing of the reflection type liquid crystal display device of the 2nd reference . It is a simulation result of the electric field applied to the liquid crystal in the electrode configuration of the reference embodiment. It is a simulation result of the electric field applied to the liquid crystal in the electrode structure of the 3rd reference . It is a cross-sectional view of a reflection type liquid crystal display device of the implementation mode of the present invention. In the electrode configuration of the embodiment, a simulation result of an electric field applied to the liquid crystal when a voltage having the same polarity as that of the pixel electrode is applied to the auxiliary common electrode. In the electrode configuration of the embodiment, a simulation result of an electric field applied to the liquid crystal when a voltage having a polarity opposite to that of the pixel electrode is applied to the auxiliary common electrode. It is a simulation result of the electric field applied to the liquid crystal in the electrode structure of the 4th reference . It is a simulation result of the electric field applied to the liquid crystal in the electrode structure of the 5th reference . It is a simulation result of the electric field applied to the liquid crystal in the electrode configuration of the sixth reference . It is a perspective view which shows an example of the electronic device provided with the reflection type liquid crystal device of this invention. It is a perspective view which shows the other example of the electronic device provided with the reflection type liquid crystal device of this invention. It is a perspective view which shows the further another example of the electronic device provided with the reflective liquid crystal device of this invention. It is a figure which shows the example of 1 structure of the conventional projection-type liquid crystal display device. It is a figure which shows the example of 1 structure of the conventional reflection mode liquid crystal light valve. It is the simulation result of the electric field applied to the liquid crystal in the liquid crystal display device of the conventional vertical alignment mode.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... TFT array substrate (element substrate), 2 ... Data line, 3 ... Scanning line, 4 ... Pixel region, 5 ... Thin film transistor (TFT, switching element), 6 ... Gate electrode, 7 ... Semiconductor layer, 8 ... Pixel electrode, DESCRIPTION OF SYMBOLS 9 ... Common electrode, 12 ... Opposite substrate, 13 ... Liquid crystal, 14 ... Reflective electrode (reflective layer), 22 ... Opposite side common electrode, 24 ... Auxiliary common electrode

Claims (1)

A liquid crystal sandwiched between a pair of substrates including an element substrate and a counter substrate; and a plurality of pixels formed in a matrix, and applying a lateral electric field to the liquid crystal in a display region formed by the plurality of pixels There line reflective display by,
Each of the plurality of pixels forming a rectangle in a plan view is
A frame-shaped common electrode formed along the peripheral edge of the rectangle;
An I-shaped pixel electrode comprising two line segments that overlap two opposite sides of the common electrode and a line segment that connects approximately the centers of the two line segments;
A switching element provided at a corner of the common electrode,
On the element substrate in the cross-sectional direction of the pixel,
The reflective electrode formed so as to cover the display region, the common electrode, and the pixel electrode are connected in this order via an insulating film,
A method of driving a reflective liquid crystal device in which an auxiliary common electrode is provided above the common electrode via an insulating film ,
Applies a first voltage is a positive voltage to a predetermined said pixel electrode, the said pixel electrodes, and the plurality of the switching to apply a second voltage which is opposite in polarity to the voltage of the first voltage Driven by the element,
Wherein the common electrode applies a third voltage having an intermediate potential between the first voltage and the second voltage,
Wherein the auxiliary common electrode, the first voltage and the reverse polarity, the driving method of the reflection-type liquid crystal device and applying a fourth potential is a voltage potential lower than the third voltage.

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