JP2009145385A - Liquid crystal device and electronic device - Google Patents

Abstract

In a liquid crystal device, a high-quality image is displayed and processing in a manufacturing process is simplified.
A liquid crystal device (1) is sandwiched between a first substrate (10), a second substrate (20) arranged to face the first substrate, and the first and second substrates, A liquid crystal layer (50) including liquid crystal molecules (50a) in which the alignment state when no voltage is applied is vertical alignment and the dielectric anisotropy is positive, and the image signal provided on the first substrate for each pixel. And a first common electrode (9b) provided for each pixel so as to be paired with the pixel electrode on the first substrate and supplied with a common potential. Is provided. Furthermore, a second common electrode (21) provided for each pixel and supplied with a common potential is provided on the second substrate so as to be closer to the first common electrode than to the pixel electrode.
[Selection] Figure 5

Description

  The present invention relates to a technical field of a liquid crystal device such as a liquid crystal light valve and a direct-view type liquid crystal display device, and an electronic apparatus such as a liquid crystal projector including the liquid crystal device.

  In this type of liquid crystal device, the quality of the displayed image is improved. For example, in Patent Document 1, in a vertical alignment matrix liquid crystal display device, an alignment control electrode is provided between pixels, an effective voltage higher or lower than all other transparent electrodes is applied thereto, and the absence of an electrode in the transparent electrode. A technique is described in which the formed alignment control window is provided and the electric field in the liquid crystal layer is adjusted to control the alignment of liquid crystal molecules. This prevents display quality from being degraded due to the appearance of disclination and improves viewing angle characteristics.

  In Patent Document 2, a thin film transistor having a drain electrode and a common electrode extending between a plurality of pixels, and a source electrode extending in the same direction as the thin film transistor, the liquid crystal composition is parallel to the substrate surface. A technique is described in which high contrast and the like are obtained by applying an electric field (ie, a “lateral electric field”).

Japanese Patent Laid-Open No. 7-64089 JP-A-6-160878

  However, according to the technique described in Patent Document 1 described above, there is a technical problem that processing in the manufacturing process may be complicated. Further, according to the technique described in Patent Document 2, there is a technical problem that it may be difficult to obtain a high contrast as compared with a vertical alignment (VA) type liquid crystal.

  The present invention has been made in view of the above problems, and provides, for example, a liquid crystal device capable of displaying a high-quality image and simple in the manufacturing process, and an electronic apparatus including the same. Is an issue.

  In order to solve the above problems, a liquid crystal device of the present invention is sandwiched between a first substrate, a second substrate disposed so as to face the first substrate, and the first and second substrates, and voltage When no voltage is applied, the alignment state is vertical alignment, and a liquid crystal layer containing liquid crystal molecules having positive dielectric anisotropy is provided for each pixel on the first substrate, and a potential corresponding to an image signal is supplied. A pixel electrode, a first common electrode provided for each of the pixels so as to form a pair with the pixel electrode on the first substrate, and a common potential supplied to the pixel electrode; A second common electrode provided for each of the pixels and supplied with the common potential so as to be closer to the first common electrode than to the pixel electrode.

  According to the liquid crystal device of the present invention, the liquid crystal layer is sandwiched between the first and second substrates each made of, for example, a glass substrate. The first substrate is typically a TFT (Thin Film Transistor) array substrate or an element substrate, and the second substrate is typically a counter substrate. The liquid crystal molecules included in the liquid crystal layer, for example, nematic liquid crystal, have positive dielectric anisotropy, and the alignment state when no voltage is applied to each of the substrate surfaces of the first and second substrates. Oriented to be vertical. Such alignment can be performed, for example, by inserting a liquid crystal for vertical alignment between alignment films for vertical alignment provided on each of the first and second substrates.

  On the first substrate, for each pixel, a pixel electrode made of, for example, an ITO (Indium Tin Oxide) film is provided, and a first common electrode made of, for example, an ITO film is provided so as to make a pair with the pixel electrode. That is, the pixel electrode and the first common electrode are provided on the same substrate. For example, a potential corresponding to an image signal is supplied to the pixel electrode from, for example, an image signal supply circuit via a data line and a pixel switching element. For example, a common potential is supplied to the first common electrode from, for example, a power supply circuit via a common wiring. Here, the common potential is a potential that is fixed at least for a predetermined period regardless of the content of the image signal, and means a potential that is commonly supplied to each pixel. The common potential may be a fixed potential that is completely fixed at a constant potential with respect to the time axis, such as a ground potential or a ground potential, or may be a first potential in an odd field period related to an image signal, for example. The fixed potential may be fixed to a fixed potential by a fixed period with respect to the time axis, such as fixed to a fixed potential and fixed to the second fixed potential in the even field period.

  On the second substrate, a second common electrode made of, for example, an ITO film is provided for each pixel. The second common electrode is provided closer to the first common electrode than to the pixel electrode. That is, the second common electrode is provided near the first common electrode between the pixel electrode and the first common electrode, or so as to overlap the first common electrode when viewed in plan on the second substrate. In other words, the second common electrode is provided such that the distance between the second common electrode and the first common electrode is shorter than the distance between the second common electrode and the pixel electrode. Similar to the first common electrode, a common potential is supplied to the second common electrode from, for example, a power supply circuit through, for example, a common wiring.

  According to the liquid crystal device of the present invention, during the operation, an applied voltage corresponding to the potential difference between the pixel electrode and the first and second common electrodes is applied to the liquid crystal layer in each pixel according to the image signal. As a result, image display is performed. Here, since both the pixel electrode and the first common electrode are formed on the first substrate, due to a potential difference between the pixel electrode and the first common electrode, a direction parallel to the substrate surface (that is, the substrate) An electric field in the direction along the plane), the so-called “lateral electric field”. Further, since the second common electrode is provided closer to the first common electrode than to the pixel electrode, a lateral electric field is generated due to a potential difference between the pixel electrode and the second common electrode. Thus, when a horizontal electric field is generated in a pixel, the direction of the liquid crystal molecules constituting the liquid crystal layer changes so as to follow the generated horizontal electric field.

  According to the inventor's research, in general, in a VA type liquid crystal device, when a voltage is applied, a convex portion for controlling the direction in which the liquid crystal molecules in the liquid crystal device are tilted must be formed on the substrate. Processing may be complicated. In addition, liquid crystal molecules having negative dielectric anisotropy used for VA liquid crystal devices are limited in material and have a small design margin. On the other hand, in an IPS (In Plane Switching) type liquid crystal device, it is sufficient to generate a lateral electric field, but in order to obtain a high contrast, a high accuracy is required for disposing a polarizing plate or the like. Then, it has been found that there is a possibility that the target contrast cannot be obtained depending on the arrangement of the polarizing plate or the like, or the cost may increase due to the arrangement failure.

  However, in the present invention, the direction of the liquid crystal molecules in which the alignment state when no voltage is applied is vertical alignment and the dielectric anisotropy is positive is the horizontal electric field generated between the pixel electrode and the first and second common electrodes. To change along (i.e. fall). Thereby, it is not necessary to form a convex portion on the substrate for controlling the direction in which the liquid crystal molecules are tilted. Therefore, processing in the manufacturing process of the liquid crystal device can be simplified. Furthermore, since the liquid crystal material having positive dielectric anisotropy is also used for TN (Twisted Nematic) liquid crystal or the like, the design margin is wide. Therefore, depending on the selection and / or combination of materials, the response speed can be increased or the cost can be reduced as compared with the existing VA liquid crystal device. In addition, since the alignment state when no voltage is applied is vertical alignment, the IPS liquid crystal device is not required to have a higher accuracy in the arrangement of the polarizing plate or the like than the IPS liquid crystal device.

  Here, if the second common electrode is not provided on the second substrate, the direction of the liquid crystal molecules constituting the liquid crystal layer is caused by the potential difference between the pixel electrode and the first common electrode provided on the first substrate. In such a case, the liquid crystal molecules in the vicinity of the middle between the pixel electrode and the first common electrode in each pixel may be misaligned (ie, disclination). . More specifically, in this case, out of the liquid crystal molecules in the vicinity of the middle between the pixel electrode and the first common electrode in each pixel, the liquid crystal molecules and the first common electrode side trying to follow the transverse electric field by falling to the pixel electrode side. If the liquid crystal molecules that fall along the horizontal electric field are prevented from collapsing with each other, the liquid crystal molecules may be poorly aligned. In a region (that is, a domain) where such an orientation failure occurs, display defects such as, for example, that the liquid crystal cannot transmit light and white cannot be displayed.

  However, in the present invention, in particular, as described above, the second common electrode is provided on the second substrate. Therefore, in the operation of the liquid crystal device, in addition to the lateral electric field generated due to the potential difference between the pixel electrode and the first common electrode, the liquid crystal device generates liquid crystal due to the lateral electric field generated due to the potential difference between the pixel electrode and the second common electrode. The liquid crystal molecules constituting the layer can be changed so that the direction thereof is along the substrate surface of the first or second substrate. Therefore, the direction in which the liquid crystal molecules constituting the liquid crystal layer are tilted can be almost or completely aligned on the first and second common electrode sides, and the occurrence of poor alignment of liquid crystal molecules in each pixel can be reduced or prevented. . That is, the domain where the above-described disclination occurs can be almost or completely eliminated, and the occurrence of display defects can be reduced or prevented. As a result, a high quality image can be displayed.

  As described above, according to the liquid crystal device of the present invention, a high-quality image can be displayed, and processing in the manufacturing process can be simplified.

  In one aspect of the liquid crystal device of the present invention, the pixel electrode is formed on the first substrate so as to extend in the first direction, and the first common electrode is formed on the first substrate in the first direction. It is formed to extend along.

  According to this aspect, the pixel electrode is formed on the first substrate so as to extend in the first direction. Here, the “first direction” is typically a direction along the substrate surface of the first substrate and a direction along one side of the first substrate. The first common electrode is formed on the first substrate so as to extend along the first direction (for example, in parallel).

  Therefore, a lateral electric field along the direction intersecting the first direction can be generated almost uniformly in the first direction between the pixel electrode and the first common electrode.

  Note that a plurality of pixel electrodes and first common electrodes are typically formed on the first substrate, and the pixel electrodes and the first common electrodes are arranged at predetermined intervals so as to be adjacent to each other.

  In another aspect of the liquid crystal device of the present invention, the second common electrode has the same planar pattern as the first common electrode.

  According to this aspect, the second common electrode is planarly viewed on the second substrate (that is, planarly viewed on the substrate surface of the second substrate, in other words, planarly on the first substrate). (See) and formed in the same plane pattern as the first common electrode. That is, for example, when the pixel electrode is formed to extend in the first direction on the first substrate, and the first common electrode is formed to extend along the first direction on the first substrate. The second common electrode is formed on the second substrate so as to extend along the first direction. Therefore, the direction in which the liquid crystal molecules constituting the liquid crystal layer are tilted can be more reliably aligned with the first and second common electrodes, and it is even more reliable that defective alignment of the liquid crystal molecules will occur in each pixel. Can be reduced or prevented.

  In the aspect in which the second common electrode has the same plane pattern as the first common electrode, the second common electrode overlaps the first common electrode when viewed in plan on the second substrate. It may be formed.

  In this case, the direction in which the liquid crystal molecules constituting the liquid crystal layer are tilted can be more reliably aligned with the first and second common electrodes, and the alignment failure of the liquid crystal molecules occurs in each pixel. It can be reduced or prevented more reliably.

  In another aspect of the electro-optical device of the present invention, a vertical alignment film for vertically aligning the liquid crystal molecules is provided on each of the first and second substrates.

  According to this aspect, the alignment state when no voltage is applied to the liquid crystal molecules can be made to be vertical alignment relatively easily. The vertical alignment film may be formed, for example, by oblique vapor deposition of an inorganic material, or a coating type vertical alignment film.

  In order to solve the above problems, an electronic device of the present invention includes the above-described liquid crystal device of the present invention (including various aspects thereof).

  According to the electronic device of the present invention, since the liquid crystal device of the present invention described above is included, a projection display device, a television, a mobile phone, an electronic notebook, a word processor, capable of performing high-quality image display, Various electronic devices such as a viewfinder type or a monitor direct-view type video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel can be realized.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the drawings referred to below, the scale of each layer and each member is different in order to make each layer and each member recognizable on the drawing.
<First Embodiment>
The liquid crystal device according to the first embodiment will be described with reference to FIGS.

  First, a liquid crystal panel constituting the liquid crystal device according to the present embodiment will be described with reference to FIGS. FIG. 1 is a plan view of a TFT array substrate as viewed from the counter substrate side together with the components formed thereon, and FIG. 2 is a cross-sectional view taken along the line H-H ′ of FIG. 1.

  1 and 2, in the liquid crystal panel 100 of the present embodiment, the TFT array substrate 10 and the counter substrate 20 are disposed to face each other. The TFT array substrate 10 is an example of the “first substrate” according to the present invention, and is made of a transparent substrate such as a quartz substrate, a glass substrate, or a silicon substrate. The counter substrate 20 is an example of a “second substrate” according to the present invention, and is made of a transparent substrate such as a quartz substrate or a glass substrate. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are surrounded by an image display region 10a corresponding to a region where a plurality of pixels are provided. They are bonded to each other by a sealing material 52 provided in the sealing area located.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or an ultraviolet / heat combination type curable resin for bonding the two substrates, and is applied to the TFT array substrate 10 in the manufacturing process, and then irradiated with ultraviolet rays. And cured by heating or the like. In the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance (ie, gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed. Note that the gap material may be arranged in the image display region 10a or a peripheral region located around the image display region 10a in addition to or instead of the material mixed in the seal material 52.

  In FIG. 1, a light-shielding frame light-shielding film 53 that defines the frame area of the image display region 10a is provided on the counter substrate 20 side in parallel with the inside of the seal region where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

  A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in a region located outside the sealing region in which the sealing material 52 is disposed in the peripheral region. The external circuit connection terminal 102 is configured such that an external circuit provided outside the liquid crystal panel 100 or an external power source can be electrically connected. During operation of the liquid crystal device, various signals such as a potential VID and a common potential LCCOM corresponding to the image signal are supplied from an external circuit or an external power source to the electrodes and circuits provided in the liquid crystal panel 100 via the external circuit connection terminal 102. .

  The sampling circuit 7 is provided so as to be covered with the frame light shielding film 53 on the inner side of the seal region along the one side. The scanning line driving circuit 104 is provided so as to be covered with the frame light-shielding film 53 inside the seal region along two sides adjacent to the one side.

  On the TFT array substrate 10, vertical conduction terminals 106 for connecting the two substrates with the vertical conduction material 107 are arranged in regions facing the four corner portions of the counter substrate 20. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20. Further, a lead wiring 90 for electrically connecting the external circuit connection terminal 102 to the data line driving circuit 101, the scanning line driving circuit 104, the vertical conduction terminal 106, and the like is formed.

  In FIG. 2, on the TFT array substrate 10, a laminated structure in which pixel switching TFTs as drive elements, wiring lines such as scanning lines and data lines are formed is formed. Although the detailed structure of this laminated structure is not shown in FIG. 2, an electrode 9 made of a transparent material such as ITO is formed in a comb-like shape in a predetermined pattern for each pixel on the laminated structure. Has been. On the surface of the TFT array substrate 10 facing the liquid crystal layer 50, that is, on the electrode 9, a vertical alignment film 16 is formed so as to cover the electrode 9.

  As will be described later with reference to FIG. 3, the electrode 9 includes a pixel electrode 9a and a common electrode 9b. During the operation of the liquid crystal device, a potential corresponding to the image signal VID is supplied from the external circuit through the external circuit connection terminal 102, the lead wiring 90, the data line driving circuit 101, the sampling circuit 7, the data line, the pixel switching TFT, and the like. The common potential LCCOM is supplied to the pixel electrode 9a, and the common potential LCCOM is supplied to the common electrode 9b from the external power source through the external circuit connection terminal 102, the lead wiring 90, and the like.

  A light shielding film 23 is formed on the surface of the counter substrate 20 facing the TFT array substrate 10. For example, the light shielding film 23 is formed in a lattice shape when viewed in plan on the facing surface of the facing substrate 20. In the counter substrate 20, a non-opening area is defined by the light shielding film 23, and an area partitioned by the light shielding film 23 is an opening area through which light emitted from the backlight is transmitted. That is, the light shielding film 23 functions as a black mask. The light shielding film 23 may be formed in a stripe shape, and the non-opening region may be defined by the light shielding film 23 and various components such as data lines provided on the TFT array substrate 10 side.

  On the light shielding film 23, the counter electrode 21 made of a transparent material such as ITO is formed in a comb-teeth shape with the same predetermined pattern as the common electrode 9b so as to face the common electrode 9b. During the operation of the liquid crystal device, the common potential LCCOM is supplied from the external power source to the counter electrode 21 through the external circuit connection terminal 102, the lead wiring 90, the vertical conduction terminal 106, the vertical conduction member 107, and the like. The counter electrode 21 is an example of the “second common electrode” according to the present invention.

  On the surface of the counter substrate 20 facing the liquid crystal layer 50, that is, on the counter electrode 21, a vertical alignment film 22 is formed so as to cover the counter electrode 21.

  In order to perform color display in the image display region 10a, a color filter (not shown in FIG. 2) is formed in a region including a part of the opening region and the non-opening region in the counter substrate 20 or the TFT array substrate 10. It may be.

  The liquid crystal layer 50 includes liquid crystal molecules having a positive dielectric anisotropy, and the pair of vertical alignment films 16 and 22 align the liquid crystal molecules so that the initial alignment state is vertical. The

  In addition to the data line driving circuit 101, the scanning line driving circuit 104, the sampling circuit 7, etc., a plurality of data lines are pre-set at a predetermined voltage level on the TFT array substrate 10 shown in FIGS. A precharge circuit that supplies a charge signal prior to an image signal, an inspection circuit for inspecting the quality, defects, and the like of the liquid crystal device during manufacture or at the time of shipment may be formed.

  Next, the configuration of the liquid crystal device according to the present embodiment will be described with reference to FIG. FIG. 3 is a perspective view showing the configuration of the liquid crystal device according to the present embodiment. In the following drawings, detailed members of the liquid crystal panel 100 shown in FIGS. 1 and 2 are omitted as appropriate, and only directly related members are shown. In the following drawings, the configuration of one pixel in the liquid crystal panel 100 is schematically shown.

  In FIG. 3, the liquid crystal device 1 includes a liquid crystal panel 100 and polarizing plates 201 and 202 disposed on both sides of the liquid crystal panel 100 along the light incident direction. The slow axis 201a in the polarizing plate 201 and the slow axis 202a in the polarizing plate 202 are orthogonal to each other (that is, in a crossed Nicols state).

  The liquid crystal panel 100 is a liquid crystal molecule that is sandwiched between the TFT array substrate 10, the counter substrate 20, the TFT array substrate 10 and the counter substrate 20, has an initial alignment state of vertical alignment, and a positive dielectric anisotropy. A liquid crystal layer 50 including 50a (see FIG. 2), a pixel electrode 9a and a common electrode 9b disposed on the TFT array substrate 10, and a counter electrode 21 disposed on the counter substrate 20 are provided.

  In each pixel, the pixel electrode 9 a is formed to extend in one direction on the TFT array substrate 10, and the common electrode 9 b is formed to extend in parallel to one direction on the TFT array substrate 10. The counter electrode 21 has the same pattern as the common electrode 9b on the counter substrate 20 (that is, extends in parallel with one direction) and is viewed in plan on the counter substrate 20 (that is, It is formed so as to overlap the common electrode 9b (as viewed from the normal direction of the substrate surface of the counter substrate 20).

  In the liquid crystal device 1, during the operation, the potential difference between the pixel electrode 9a, the common electrode 9b, and the counter electrode 21 (that is, the potential difference between the potential corresponding to the image signal VID and the common potential LCCOM) is added to the liquid crystal layer 50 in each pixel. When an applied voltage corresponding to is applied, image display is performed.

  Next, the operation of the liquid crystal molecules when a voltage is applied to the liquid crystal layer of the liquid crystal device according to the present embodiment will be described with reference to FIGS. FIG. 4 is a conceptual diagram showing the state of liquid crystal molecules in the liquid crystal layer when no voltage is applied, and FIG. 5 is a conceptual diagram showing the state of liquid crystal molecules in the liquid crystal layer when a voltage is applied. It is.

  As shown in FIG. 4, when no voltage is applied between the pixel electrode 9a, the common electrode 9b, and the counter electrode 21 (in other words, the potential corresponding to the image signal VID supplied to the pixel electrode 9a and the common electrode). 9a and the common potential LCCOM supplied to the counter electrode 21), the liquid crystal molecules 50a have a major axis direction perpendicular to the substrate surface between the TFT array substrate 10 and the counter substrate 20. (I.e., vertically aligned). In this case, since the light irradiated to the liquid crystal device 1 is not affected by the liquid crystal molecules 50a, the light is blocked by the polarizing plates 201 and 202 (that is, black display is performed).

  On the other hand, as shown in FIG. 5, when a voltage is applied between the pixel electrode 9a, the common electrode 9b, and the counter electrode 21 (in other words, the potential corresponding to the image signal VID supplied to the pixel electrode 9a) In the case where the common potential LCCOM supplied to the common electrode 9a and the counter electrode 21 is different from each other), the liquid crystal molecules 50a are arranged so that the major axis direction is along the substrate surface between the TFT array substrate 10 and the counter substrate 20. Oriented. In this case, the light irradiated to the liquid crystal device 1 changes its polarization state due to a change in birefringence of the liquid crystal molecules 50a due to falling sideways, and passes through the liquid crystal panel 100 and the polarizing plates 201 and 202 ( That is, the display is white. For example, the common potential LCCOM supplied in common to the common electrode 9b and the counter electrode 21 of each pixel is a ground potential, and the potential corresponding to the image signal is positive or negative in the pixel electrode 9a every predetermined period. It is supplied so as to be at a potential.

  Strictly speaking, when a voltage is applied, the major axis direction of the liquid crystal molecules 50a follows the electric field generated between the pixel electrode 9a and the common electrode 9b and the electric field generated between the pixel electrode 9a and the counter electrode 21. To change. Therefore, in the vicinity of the pixel electrode 9a, the common electrode 9b, and the counter electrode 21, the change (that is, the inclination) of the liquid crystal molecules 50a is reduced and the light transmittance is reduced, but the influence on the image displayed on the liquid crystal panel 100 is reduced. Has been found to be small by research of the present inventors.

  Conversely, the vicinity of the common electrode 9b and the counter electrode 21 where the light transmittance is reduced can be hidden by the light shielding film 23 functioning as a black mask described above with reference to FIG.

  Next, in addition to FIG. 5, the operation of liquid crystal molecules when a voltage is applied to the liquid crystal layer will be described in more detail with reference to a comparative example shown in FIG. FIG. 6 is a schematic diagram having the same concept as in FIG. 5 in the comparative example.

  As shown in FIG. 6 as a comparative example, it is assumed that the counter electrode 21 is not provided on the counter substrate 20, and the major axis direction of the liquid crystal molecules 50a is the pixel electrode 9a and the common electrode 9a provided on the TFT array substrate 10. When configured so as to follow an electric field generated due to a potential difference between them, the liquid crystal molecules (for example, liquid crystal molecules 50a1 in FIG. 6) are aligned in the vicinity of the middle between the pixel electrode 9a and the common electrode 9b in each pixel. There is a risk of failure.

  That is, according to the liquid crystal device according to the comparative example shown in FIG. 6, during the operation, the liquid crystal molecules 50 a in the vicinity of the middle between the pixel electrode 9 a and the common electrode 9 b in each pixel are tilted toward the pixel electrode 9 a side. The liquid crystal molecules 50a2 that are to be along the surface and the liquid crystal molecules 50a1 that are to be along the substrate surface by being tilted toward the common electrode 9b prevent the liquid crystal molecules 50a2 from being tilted to each other, thereby causing misalignment of liquid crystal molecules (that is, disclination). It may occur. Thereby, for example, in the image display area 10a (see FIG. 1), a region that should become white when the liquid crystal molecules 50a1 are tilted is displayed black because the liquid crystal molecules 50a1 are not tilted sufficiently. The above problems may occur.

  However, in the present embodiment, the counter electrode 21 is provided on the counter substrate 20 as described above with reference to FIGS. 1 to 5.

  Therefore, in FIG. 5, according to the liquid crystal device 1 according to the present embodiment, during the operation, in addition to the electric field generated due to the potential difference between the pixel electrode 9a and the common electrode 9b, between the pixel electrode 9a and the counter electrode 21. The liquid crystal molecules 50a can be changed (that is, tilted) so that the major axis direction is along the substrate surface by the electric field generated due to the potential difference. Therefore, the direction in which the liquid crystal molecules 50a are tilted can be almost or completely aligned with the common electrode 9b and the counter electrode 21 side, and the occurrence of poor alignment of liquid crystal molecules in each pixel can be reduced. That is, for example, all of the liquid crystal molecules 50a1 and 50a2 in the vicinity of the middle between the pixel electrode 9a and the common electrode 9b in each pixel can be inclined to the common electrode 9b and the counter electrode 21 side. Thereby, it is possible to reduce the occurrence of defects on display due to alignment failure of liquid crystal molecules. As a result, a high quality image can be displayed.

  In this embodiment, the counter electrode 21 is formed on the counter substrate 20 so as to have the same pattern as the common electrode 9b and to overlap the common electrode 9b when viewed in plan on the counter substrate 20. However, even if the counter electrode 21 has a pattern different from that of the common electrode 9b or does not overlap with the common electrode 9b, the counter electrode 20 has a pattern with respect to the common electrode 9b rather than the pixel electrode 9a. If the liquid crystal molecules 50a are formed so as to be close to each other, it is possible to reduce the occurrence of alignment failure of the liquid crystal molecules 50a in each pixel, as in the present embodiment.

  Further, according to the liquid crystal device 1 according to the present embodiment, it is not necessary to form a convex portion for controlling the direction in which the liquid crystal molecules 50 a are tilted on the TFT array substrate 10 or the counter substrate 20. Therefore, processing in the manufacturing process of the liquid crystal device can be simplified. Furthermore, since the liquid crystal layer 50 includes liquid crystal molecules having positive dielectric anisotropy, the design margin is wide. Therefore, depending on the selection and / or combination of the liquid crystal materials, the response speed can be made faster than the existing VA liquid crystal device or the cost can be reduced.

As described above, according to the liquid crystal device 1 according to the present embodiment, a high-quality image can be displayed, and processing in the manufacturing process can be simplified.
<Electronic equipment>
Next, a case where the above-described liquid crystal device is applied to a projector which is an example of an electronic apparatus will be described with reference to FIG. The liquid crystal device described above is used as a light valve of a projector. FIG. 7 is a plan view showing a configuration example of the projector.

  As shown in FIG. 7, a projector 1100 includes a lamp unit 1102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

  The configurations of the liquid crystal panels 1110R, 1110B, and 1110G are the same as those of the liquid crystal device described above, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In the dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Therefore, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

  Here, paying attention to the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display image by the liquid crystal panel 1110G needs to be horizontally reversed with respect to the display images by the liquid crystal panels 1110R and 1110B.

  In addition, since light corresponding to each primary color of R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  In addition to the electronic device described with reference to FIG. 7, a mobile personal computer, a mobile phone, a liquid crystal television, a viewfinder type, a monitor direct view type video tape recorder, a car navigation device, a pager, and an electronic notebook , Calculators, word processors, workstations, videophones, POS terminals, devices with touch panels, and the like. Needless to say, the present invention can be applied to these various electronic devices.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. An electronic device including the liquid crystal device is also included in the technical scope of the present invention.

It is a top view which shows the whole structure of the liquid crystal device which concerns on 1st Embodiment. It is the H-H 'sectional view taken on the line of FIG. It is a perspective view which shows the structure of the liquid crystal device which concerns on 1st Embodiment. It is a conceptual diagram which shows the state of the liquid crystal molecule in case the voltage is not applied in the liquid crystal device which concerns on 1st Embodiment. It is a conceptual diagram which shows the state of the liquid crystal molecule when the voltage is applied in the liquid crystal device which concerns on 1st Embodiment. It is a conceptual diagram which shows the state of the liquid crystal molecule when the voltage is applied in the liquid crystal device which concerns on a comparative example. It is a top view which shows the structural example of the projector as an example of the electronic device which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal device, 9a ... Pixel electrode, 9b ... Common electrode, 10 ... TFT array substrate, 20 ... Counter substrate, 21 ... Counter electrode, 50 ... Liquid crystal layer, 50a ... Liquid crystal molecule, 100 ... Liquid crystal panel, 201, 202 ... Polarizer

Claims (6)

A first substrate;
A second substrate disposed to face the first substrate;
A liquid crystal layer comprising liquid crystal molecules sandwiched between the first and second substrates, the alignment state when no voltage is applied is vertical alignment, and the dielectric anisotropy is positive;
A pixel electrode provided for each pixel on the first substrate and supplied with a potential according to an image signal;
A first common electrode provided for each of the pixels so as to form a pair with the pixel electrode on the first substrate;
A second common electrode that is provided for each of the pixels so as to be closer to the first common electrode than to the pixel electrode on the second substrate. A liquid crystal device characterized by the above. The pixel electrode is formed to extend in a first direction on the first substrate,
The liquid crystal device according to claim 1, wherein the first common electrode is formed to extend along the first direction on the first substrate.   3. The liquid crystal device according to claim 1, wherein the second common electrode has the same planar pattern as the first common electrode.   4. The liquid crystal device according to claim 3, wherein the second common electrode is formed to overlap the first common electrode when viewed in plan on the second substrate.   5. The liquid crystal device according to claim 1, further comprising a vertical alignment film for vertically aligning the liquid crystal molecules on each of the first and second substrates.   An electronic apparatus comprising the liquid crystal device according to claim 1.