JP2008015228A - Liquid crystal device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal device for displaying of high picture quality and wide viewing angle in both of reflection display and transmission display with respect to a transflective liquid crystal device using an in-plain switching mode. <P>SOLUTION: The liquid crystal device is the transflective liquid crystal device using an in-plain switching mode, wherein an alignment direction 151 of an alignment film disposed on a transmission display region T and an alignment direction 152 of an alignment film disposed on a reflection display region R are different from each other and a light shielding layer 60 is disposed so as to superimpose the boundary part of both regions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal device and an electronic apparatus.

In the liquid crystal device, since the tilt of the liquid crystal molecules is directional, there is a problem of viewing angle dependency such as a change in display color and contrast depending on the viewing direction of the display element. As a method for improving this, there is known a method for controlling the alignment of liquid crystal molecules by applying an electric field in the direction of the substrate surface to the liquid crystal layer (hereinafter referred to as a transverse electric field method), and an electrode for generating the electric field. There are known what is called an IPS (In-Plane Switching) system, an FFS (Fringe-Field Switching) system, and the like. Recently, for the purpose of widening the viewing angle by the horizontal electric field method, it has been proposed to apply the horizontal electric field method to a transflective liquid crystal device (see, for example, Patent Document 1).
JP 2005-196176 A

  When the transflective liquid crystal device adopts the horizontal electric field method, the polarization mode is different between the transmissive display area and the reflective display area. The mode must be the same. Such a structure can be realized by adopting a technique called orientation division. As a method for performing alignment division, a method called mask rubbing in which rubbing is performed in a plurality of times for each region using a resist mask is conventionally known. In recent years, liquid crystal alignment control technology without rubbing, in particular, a photo alignment method that generates liquid crystal alignment by irradiating polarized light onto a coating film provided on a substrate has attracted attention. Also, an alignment dividing method using this photo-alignment method has been studied.

  However, when alignment division is performed by the above-described method, if the position of the alignment processing boundary, that is, the position of the alignment division mask is shifted, black and white inversion occurs at the boundary between the reflective display area and the transmissive display area. In some cases, the contrast is lowered. In addition, when the alignment is divided, the alignment direction of the liquid crystal is different at the boundary between these regions. Therefore, the alignment disorder occurs in the liquid crystal at the boundary between the two regions, and the display contrast is lowered. ing.

  The present invention has been made in view of such circumstances, and in the case of adopting an alignment division method in which the alignment of the liquid crystal is different for each region, the display is prevented from being disturbed at the boundary portion, and has high quality. It is another object of the present invention to provide a liquid crystal device and an electronic apparatus that can realize high-contrast display.

  In order to solve the above problems, a liquid crystal device of the present invention includes a first substrate provided with a first electrode and a second electrode, a second substrate facing the first substrate, the first substrate, and the first substrate. A liquid crystal sandwiched between two substrates and driven by an electric field generated between the first electrode and the second electrode, and provided on the liquid crystal side surface of the first substrate and the second substrate. An alignment film, a plurality of alignment regions that are provided in the alignment film and align liquid crystals in different directions, and a light-shielding layer that is provided so as to overlap a boundary portion between the alignment regions having different alignment directions. It is characterized by that.

  According to this configuration, since the light shielding layer is provided at the boundary portion of the alignment region, even if a positional shift occurs in the alignment process of each alignment region and light leakage occurs at the boundary portion, the light leakage is prevented from occurring. Thus, light can be reliably shielded. In addition, when a plurality of alignment regions having different alignment directions are provided in the alignment film, the alignment may be disturbed at the boundary and light leakage may occur. can do.

  In the present invention, the plurality of alignment regions are irradiated with light to the alignment film material forming the alignment film, and are subjected to a photo-alignment process that induces rearrangement or anisotropic chemical reaction in the molecules of the alignment film material. It is desirable that it is formed by being formed.

  Photo-alignment treatment is an alignment treatment in which an organic thin film (orientation film material) with photoreactivity is formed on a substrate and molecules in the film are aligned in one direction by irradiation with polarized ultraviolet rays or the like to provide an alignment function. Say. This photo-alignment treatment is based on photo-dimerization of photo-alignment groups such as cinnamoyl group, coumarin group, chalcone group, benzophenone group, etc., and photo-isomerization of azo group, etc. that express the photo-alignment function in the alignment film material. There are reports of photodecomposition of polyimide resin and the like. Since the alignment process is performed without contact with the substrate, the optical alignment process does not cause TFT damage due to dust adhesion or generation of static electricity compared to the contact type alignment process such as rubbing, resulting in a decrease in display characteristics. Can also be avoided. Further, the alignment division can be easily performed by changing the polarization direction of the irradiated light for each alignment region.

  In the present invention, the alignment regions having different alignment directions may correspond to a reflective display region for performing reflective display and a transmissive display region for performing transmissive display, respectively.

  According to this configuration, it is possible to display an image with high contrast in a transflective liquid crystal device including a reflective display region and a transmissive display region.

  In this specification, the “reflective display area” refers to an area in which display using light incident from the display surface side of the liquid crystal device (external light or light from the front light) is possible. "" Refers to an area in which display using light (light from a backlight) incident from the back side (the side opposite to the display surface) of the liquid crystal device is possible.

  In the present invention, each of the first electrode and the second electrode includes one or a plurality of strip electrodes, and the strip electrode of the first electrode and the strip electrode of the second electrode are the reflection electrodes. The display area and the transmissive display area are arranged in parallel to each other, and the extending direction of the strip electrode in the reflective display area and the extending direction of the strip electrode in the transmissive display area are mutually It can be in different directions.

  According to this configuration, the direction of the electric field in the transmissive display region and the direction of the electric field in the reflective display region can be easily made different. As described above, in the transflective liquid crystal device, the number of times display light passes through the liquid crystal layer differs between the transmissive display area and the reflective display area. The orientation needs to be different. In the present invention, the direction of the electric field, that is, the alignment direction of the liquid crystal is different between the reflective display area and the transmissive display area. By appropriately controlling this, the amount of light modulation is adjusted between the reflective display area and the transmissive display area. Can be included. Moreover, since it is realizable only with an electrode shape, the advantage that it can manufacture at low cost with a simple process is also acquired.

  In the present invention, it is desirable that the light shielding layer is provided on the second substrate. The light shielding layer is preferably made of a metal such as Cr.

  By forming the light shielding layer with a metal such as Cr having a high light shielding performance, display with high contrast becomes possible. Further, when the light shielding layer is provided on the second substrate, the light shielding layer does not cause distortion in the electric field between the first electrode and the second electrode, so that a liquid crystal device having excellent display quality is provided. .

  An electronic apparatus according to the present invention includes the above-described liquid crystal device according to the present invention.

  According to this configuration, it is possible to provide an electronic apparatus including a display unit capable of high image quality, wide viewing angle reflection display and transmission display.

  Hereinafter, a liquid crystal device according to an embodiment of the present invention will be described with reference to the drawings. The liquid crystal device according to the present embodiment has an IPS (In-Plane Switching) method among horizontal electric field methods in which an electric field (transverse electric field) in the direction of the substrate surface is applied to liquid crystal and image alignment is controlled. This is a liquid crystal device that employs a so-called method. In the drawings referred to in each embodiment, each layer and each member are displayed in different scales so that each layer and each member have a size that can be recognized on the drawing.

  The liquid crystal device of the present embodiment is a color liquid crystal device having a color filter on a substrate, one for each of three sub-pixels that output R (red), G (green), and B (blue) light. This constitutes the pixel. Therefore, a display area that is a minimum unit constituting the display is referred to as a “sub-pixel area”. A display area composed of a set (R, G, B) of sub-pixels is referred to as a “pixel area”.

  FIG. 1 is a circuit configuration diagram of a plurality of sub-pixel regions formed in a matrix that constitutes the liquid crystal device of the present embodiment. FIG. 2 is a plan configuration diagram in an arbitrary one sub-pixel region of the liquid crystal device 100. FIG. 3 is a partial cross-sectional configuration diagram taken along the line AA ′ in FIG. 2.

  As shown in FIG. 1, a pixel electrode 9 and a TFT 30 for switching control of the pixel electrode 9 are formed in a plurality of sub-pixel areas formed in a matrix that constitutes an image display area of the liquid crystal device 100. The data line 6 a extending from the data line driving circuit 101 is electrically connected to the source of the TFT 30. The data line driving circuit 101 supplies the image signals S1, S2,..., Sn to each pixel via the data line 6a. The image signals S1 to Sn may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a.

  Further, the scanning line 3a extending from the scanning line driving circuit 102 is electrically connected to the gate of the TFT 30, and the scanning signal G1 is supplied from the scanning line driving circuit 102 to the scanning line 3a in a pulse manner at a predetermined timing. , G2,..., Gm are applied to the gate of the TFT 30 in the order of lines in this order. The pixel electrode 9 is electrically connected to the drain of the TFT 30. The TFT 30 serving as a switching element is turned on for a certain period by the input of scanning signals G1, G2,..., Gm, so that the image signals S1, S2,. Writing is performed on the pixel electrode 9.

  Image signals S1, S2,..., Sn written to the liquid crystal via the pixel electrode 9 are held for a certain period between the pixel electrode 9 and the common electrode opposed via the liquid crystal. Here, in order to prevent the held image signal from leaking, a storage capacitor 70 is provided in parallel with the liquid crystal capacitor formed between the pixel electrode 9 and the common electrode. The storage capacitor 70 is provided between the drain of the TFT 30 and the capacitor line 3b.

  Next, a detailed configuration of the liquid crystal device 100 will be described with reference to FIGS. First, the liquid crystal device 100 has a configuration in which a liquid crystal layer 50 is sandwiched between a TFT array substrate (first substrate) 10 and a counter substrate (second substrate) 20 as shown in FIG. Is sealed between the substrates 10 and 20 by a sealing material (not shown) provided along the edge of the region where the TFT array substrate 10 and the counter substrate 20 face each other. A backlight (illuminating device) 90 including a light guide plate 91, a reflecting plate 92, and a light source 93 is provided on the back side (the lower side in the drawing) of the counter substrate 20.

  As shown in FIG. 2, in the sub-pixel region of the liquid crystal device 100, a data line 6a extending in the Y-axis direction corresponding to the longitudinal direction of the sub-pixel region and a scanning line 3a extending in the X-axis direction corresponding to the short-side direction of the sub-pixel region. And the capacitor line 3b are wired in a substantially lattice shape in a plan view, and a substantially comb-like shape in a plan view is formed in a substantially rectangular region in plan view surrounded by the data line 6a, the scanning line 3a, and the capacitor line 3b. Thus, a pixel electrode (first electrode) 9 extending in the Y-axis direction and a common electrode (second electrode) 19 extending in the Y-axis direction in a substantially comb-like shape in plan view and meshing with the pixel electrode 9 are formed. ing. The TFT array substrate 10 and the counter substrate 20 are spaced apart from each other at a predetermined interval in the upper left corner of the figure, which is in the vicinity of the intersection of the data line 6a and the scanning line 3a outside the sub-pixel region, and the liquid crystal layer thickness (cell gap) Columnar spacers 40 are erected in order to maintain a constant value.

  A color filter 22 having substantially the same planar shape as the sub pixel area is provided in the sub pixel area. In addition, an area that occupies approximately half of the sub-pixel area and that is opposite to the side where the TFT 30 is provided (planar area in the lower half of the extended area of the pixel electrode 9 and the common electrode 19). A reflective layer 29 is provided. The reflective layer 29 is formed by patterning a light reflective metal film such as aluminum or silver. As shown in FIG. 2, among the planar regions surrounded by the pixel electrode 9 and the common electrode 19, the planar region that overlaps with the reflective layer 29 is the reflective display region R of the subpixel region, and the remaining region is This is a transmissive display area T. As the reflective layer 29, it is preferable to use a surface provided with irregularities on the surface thereof to impart light scattering properties. With such a configuration, the visibility in reflective display can be improved.

  The pixel electrode 9 has a substantially L-shaped base end portion 9a extending along the data line 6a and the capacitor line 3b, and a plurality (three in the drawing) extending from the base end portion 9a and extending along the X-axis direction. Strip electrode 9c, a plurality (two in the drawing) strip electrode 9d extending in an oblique direction with respect to the extending direction of strip electrode 9c, and a contact portion extending from base end portion 9a in the vicinity of capacitance line 3b 9b. The pixel electrode 9 is an electrode member formed by patterning a transparent conductive material such as ITO (indium tin oxide).

  The common electrode 19 is formed at a position overlapping the scanning line 3a in a plane and extends in the X-axis direction, and the main line portion 19a extends in the X-axis direction, and extends in the Y-axis direction along the side edge portion of the sub-pixel region. A base end 19b extending from the base end 19b, and two strip electrodes 19c and three strip electrodes 19d extending from the base end 19b. The two strip electrodes 19c are alternately arranged with the strip electrodes 9c of the pixel electrode 9, and extend in parallel to the strip electrodes 9c. On the other hand, the three strip-shaped electrodes 19d are alternately arranged with the strip-shaped electrodes 9d extending in the oblique direction in the figure, and extend in parallel with these strip-shaped electrodes 9d. The common electrode 19 is also formed using a transparent conductive material such as ITO. The pixel electrode 9 and the common electrode 19 can be formed using a metal material such as chromium in addition to the transparent conductive material.

  In each sub-pixel region, the extending directions of the strip electrodes 9c, 9d, 19c, 19d constituting the pixel electrode 9 and the common electrode 19 are different in the reflective display region R and the transmissive display region T. That is, the strip electrodes 9c and 19c disposed in the transmissive display region T are formed to extend in parallel with the X-axis direction, while the strip electrodes 9d and 19d disposed in the reflective display region R are the strip electrodes 9c and 19c. And extending in a direction (diagonal direction) intersecting with.

  In the sub-pixel region shown in FIG. 2, a voltage is generated between the five strip electrodes 9c and 9d extending in the X-axis direction and the five strip electrodes 19c and 19d disposed between the strip electrodes 9c and 9d. Is applied, and the liquid crystal is driven by an electric field (lateral electric field) in the XY plane direction (substrate plane direction) generated thereby. Further, since the pixel electrode 9 and the common electrode 19 are configured as described above, lateral electric fields in different directions are formed in the transmissive display region T and the reflective display region R when a voltage is applied.

  The TFT 30 is provided near the intersection of the data line 6a extending in the X-axis direction and the scanning line 3a extending in the Y-axis direction, and is an island-like amorphous partly formed in the plane region of the scanning line 3a. A semiconductor layer 35 made of a silicon film, a source electrode 6b formed partially overlapping the semiconductor layer 35 in a plan view, and a drain electrode 32 are provided. The scanning line 3 a functions as a gate electrode of the TFT 30 at a position overlapping the semiconductor layer 35 in plan view.

  The source electrode 6 b of the TFT 30 is a substantially inverted L-shaped wiring in plan view that branches from the data line 6 a and extends to the semiconductor layer 35. The drain electrode 32 is electrically connected to the connection wiring 31a extending along the side edge of the sub-pixel region at the −Y side end, and the end on the opposite side of the sub-pixel region through the connection wiring 31a. The capacitor electrode 31 formed at the edge is electrically connected. The capacitor electrode 31 is a conductive member having a substantially rectangular shape in a plan view formed so as to overlap with the capacitor line 3b in a plan view, and the contact portion 9b of the pixel electrode 9 is disposed on the capacitor electrode 31 so as to overlap with the plane. The capacitor electrode 31 and the pixel electrode 9 are electrically connected through a pixel contact hole 45 provided at the position. In addition, a storage capacitor 70 having the capacitor electrode 31 and the capacitor line 3b as electrodes is formed in a region where the capacitor electrode 31 and the capacitor line 3b overlap in a plane.

  A light shielding layer 60 is provided at the boundary between the transmissive display region T and the reflective display region R. The light shielding layer 60 is provided along the X-axis direction so as to overlap the boundary portion between the transmissive display region T and the reflective display region R in plan view. In FIG. 2, the light shielding layer 60 is formed in a stripe shape along the X axis, but may be formed in a lattice shape along the outer peripheral portion of the sub-pixel region.

  Next, looking at the cross-sectional structure shown in FIG. 3, the liquid crystal layer 50 is sandwiched between the TFT array substrate 10 and the counter substrate 20 that are arranged to face each other. A retardation plate 16 and a polarizing plate 14 are sequentially laminated on the outer surface side of the TFT array substrate 10 (on the side opposite to the liquid crystal layer 50), and a polarizing plate 24 is disposed on the outer surface side of the counter substrate 20. ing. The phase difference plate 16 is a λ / 4 phase difference plate that gives a phase difference of approximately ¼ wavelength to transmitted light. By providing the phase difference plate 16, the retardation of the transmissive display area T and the reflective display area R can be adjusted, whereby the display characteristics of the reflective display and the transmissive display can be aligned to, for example, normally black.

  The TFT array substrate 10 has a translucent substrate body 10A such as glass, quartz, or plastic as a base, and the inner surface side (the liquid crystal layer 50 side) of the substrate body 10A is a reflection made of a metal film such as aluminum or silver. A layer 29 is partially formed in the sub-pixel region. A first interlayer insulating film 12 made of a transparent insulating material such as silicon oxide is formed so as to cover the reflective layer 29. On the first interlayer insulating film 12, a scanning line 3a and a capacitor line 3b are formed, and a gate insulating film 11 made of a transparent insulating material such as silicon oxide is formed to cover the scanning line 3a and the capacitor line 3b. Yes.

  A semiconductor layer 35 made of amorphous silicon is formed on the gate insulating film 11, and a source electrode 6b and a drain electrode 32 are provided so as to partially run over the semiconductor layer 35. The source electrode 6b and the drain electrode A capacitive electrode 31 is formed at a position facing the capacitive line 3 b in the same layer as the electrode 32. As shown in FIG. 2, the drain electrode 32 is formed integrally with the connection wiring 31 a and the capacitor electrode 31. The semiconductor layer 35 is opposed to the scanning line 3 a via the gate insulating film 11, and the scanning line 3 a constitutes the gate electrode of the TFT 30 in the facing region. The capacitor electrode 31 and the capacitor line 3b facing the capacitor electrode 31 form a storage capacitor 70 having the gate insulating film 11 as its dielectric film.

  A second interlayer insulating film 13 made of silicon oxide or the like is formed so as to cover the semiconductor layer 35, the source electrode 6 b, the drain electrode 32, and the capacitor electrode 31, and a transparent material such as ITO is formed on the second interlayer insulating film 13. A pixel electrode 9 and a common electrode 19 made of a conductive material are formed. A pixel contact hole 45 that reaches the capacitor electrode 31 through the second interlayer insulating film 13 is formed, and a part of the contact portion 9b of the pixel electrode 9 is embedded in the pixel contact hole 45, whereby the pixel electrode 9 and the capacitor electrode 31 are electrically connected. In the transmissive display region T and the reflective display region R, strip electrodes 9c and 9d and strip electrodes 19c and 19d are alternately arranged. The main line portion 19a of the common electrode 19 includes the semiconductor layer 35, the source electrode 6b, And the drain electrode 32 and the second interlayer insulating film 13 so as to face each other. An alignment film 18 is formed so as to cover the pixel electrode 9 and the common electrode 19.

  The alignment film 18 is formed with a photoreactive organic thin film (alignment film material) on a substrate and irradiated with polarized ultraviolet rays, etc., so that molecules in the film are aligned in one direction to have an alignment function. Is. As this photo-alignment treatment, a photo-alignment group that develops a photo-alignment function in the alignment film material, for example, by photodimerization of cinnamoyl group, coumarin group, chalcone group, benzophenone group, etc., by photoisomerization of azo group, etc. And those obtained by photolysis of polyimide resin or the like can be used. Further, as disclosed in JP-A-2006-018106, JP-A-2002-250924, JP-A-11-12242, or JP-A-2005-173548, an alignment film material is irradiated by irradiating non-polarized ultraviolet rays. It is also possible to use a known alignment film material for performing rearrangement and photo-alignment treatment.

  FIG. 4 is a schematic perspective view of a polarization exposure apparatus 80 which is an example of a photo-alignment processing apparatus. This polarization exposure apparatus 80 includes a rod-shaped dielectric excimer discharge lamp 81 in which a mixed gas of xenon and chlorine is sealed in a discharge vessel, and a bowl-shaped condensing light whose ultraviolet light emitted from the lamp 81 is reflected in an elliptic shape. A mirror 82, a rectangular polarizer 83 having one side that is the same or slightly longer than the light emission length of the lamp 81, and an exposure mask 84 are provided. Here, the lamp 81 is arranged so that its longitudinal direction coincides with the longitudinal direction of the bowl-shaped condenser mirror 82, and is positioned at the first focal point of the bowl-shaped condenser mirror 82 having an elliptical cross section. Has been placed. Further, the polarizer 83 is arranged so that its longitudinal direction coincides with the longitudinal direction of the lamp 81. In addition, a TFT array substrate 10 is disposed as an irradiation object at the second focal point (position where the polarized light has the highest illuminance) of the bowl-shaped condenser mirror 82.

  Here, an alignment film material 18 </ b> A is formed on the surface of the TFT array substrate 10. As the alignment film material 18A, for example, a material that can control the alignment direction of molecules by the above-described photodimerization reaction is used. Two types of masks 84 and polarizers 83 are prepared for the transmissive display area and the reflective display area, respectively. The mask 84T for the transmissive display area is a mask having a light transmissive part in the transmissive display area of the TFT array substrate 10, and the mask 84R for the reflective display area has a light transmissive part in the reflective display area of the TFT array substrate 10. It is a mask. The transmissive display region polarizer 83T is a polarizer that transmits only a light component having a polarization direction with a predetermined angle with respect to the Y axis, and the reflective display region polarizer 83R is transmissive display region polarizer. The polarizer 83 transmits only a light component having a polarization direction different from the polarization direction of the polarizer 83T.

  In this polarized light exposure apparatus 80, first, a transmissive display area mask 83T is disposed to face the TFT array substrate 10 as an object to be illuminated, and a discharge lamp 81, a bowl-shaped condensing mirror 82, and a transmissive display area polarized light are disposed thereon. A polarization illumination device 85 including a child 83T is disposed. The TFT array substrate 10 is irradiated with the polarized ultraviolet ray 85 radiated from the polarization illumination device 85 through the transmission display area mask 84T while scanning the polarization illumination device 85 in the direction of the arrow shown in the figure. Thereby, in the transmissive display region of the TFT array substrate 10, the molecules of the alignment film material 18A are aligned in a direction perpendicular to the polarization direction of the polarized ultraviolet light. Next, the transmissive display region mask 84 and the transmissive display region polarizer 83T are replaced with the reflective display region mask 84R and the reflective display region polarizer 83R, and the TFT array substrate 10 is irradiated with polarized ultraviolet rays in the same manner. . Thereby, in the reflective display region of the TFT array substrate 10, the molecules of the alignment film material 18A are aligned in a direction different from the alignment direction of the alignment film material 18A in the transmissive display region. Then, the alignment film 18 is formed by heat-curing the alignment film material 18A thus aligned. In this way, when the polarization direction of the polarized ultraviolet light is varied from region to region, in the alignment film 18, alignment regions having different alignment directions are formed in the transmissive display region T and the reflective display region R, and the regions T, R Display characteristics suitable for the camera can be obtained.

  Returning to FIG. 3, the color filter 22 is provided on the inner surface side (the liquid crystal layer 50 side) of the counter substrate 20. The color filter 22 is preferably configured to be divided into two types of regions having different chromaticities in the sub-pixel region. As a specific example, a first color material region is provided corresponding to the planar region of the transmissive display region T, and a second color material region is provided corresponding to the planar region of the reflective display region R. A configuration in which the chromaticity of the first color material region is larger than the chromaticity of the second color material region can be employed. By adopting such a configuration, it is possible to prevent the chromaticity of the display light from being different between the transmissive display region T where the display light is transmitted only once through the color filter 22 and the reflective display region R where the display light is transmitted twice. The display quality can be improved by aligning the appearance of the reflective display and the transmissive display.

  Further, it is preferable that a planarizing film made of a transparent resin material or the like is further laminated on the color filter 22. Thereby, the surface of the counter substrate 20 can be flattened to make the thickness of the liquid crystal layer 50 uniform, and it is possible to prevent the drive voltage from becoming non-uniform in the sub-pixel region and lowering the contrast.

  On the color filter 22, a light shielding layer 60 is laminated. The light shielding layer 60 is formed of a metal material such as Cr having a high light shielding property, but can also be collectively formed of a black matrix (black resin) provided in the color filter. The light shielding layer 60 is formed in a stripe shape so as to cover the boundary between the transmissive display region T and the reflective display region R, and the width thereof is, for example, about 6 μm to 8 μm. When the light shielding layer 60 is formed on the counter substrate, if a counter electrode exists on the surface of the counter substrate, a battery reaction may occur when the light shielding layer is patterned, and the underlying counter electrode may be damaged. Since the liquid crystal device of the embodiment is a horizontal electric field type liquid crystal device and does not have a counter electrode, such a problem does not occur even if the light shielding layer 60 is formed of a metal film such as Cr.

  An alignment film 28 is formed on the color filter 22 so as to cover the light shielding layer 60. The alignment film 28 has a photoreactive organic thin film (alignment film material) formed on a substrate and irradiated with polarized ultraviolet rays to align molecules in the film in one direction so as to have an alignment function. It is. The alignment film 28 is irradiated with polarized ultraviolet rays having different polarization directions in the transmissive display area T and the reflective display area R using the polarization exposure apparatus 80 of FIG. Thus, alignment regions having different alignment directions are formed in the transmissive display region T and the reflective display region R. The alignment direction in each of the regions T and R is the same as that of the alignment film 18.

  FIG. 5 is a plan view showing the relationship between the orientation processing direction and the electric field application direction in the transmissive display region T and the reflective display region R. FIG. FIG. 5A is a schematic plan view of a sub-pixel region showing the alignment state of the liquid crystal molecules 51 in a state where no voltage is applied to the pixel electrode 9 (non-selection state), and FIG. FIG. 5 is a schematic plan view of a sub-pixel region showing an alignment state of liquid crystal molecules 51 in a state where a voltage is applied to (selected state).

The arrangement of the optical axes in the liquid crystal device of the present embodiment is as follows. That is, the alignment films 18 and 28 are subjected to alignment treatment in the same direction in a plan view, the direction of orientation is the angle theta _T only a direction inclined with respect to the Y axis in the transmissive display region T (reference numeral 151), the reflection In the display area R, the direction is parallel to the Y axis (reference numeral 152). The transmission axis of the polarizing plate 14 on the TFT array substrate 10 side is arranged in a direction orthogonal to the alignment direction of the alignment films 18 and 28 in the transmission display region T (the direction inclined by the angle θ _{T with} respect to the Y axis). The transmission axis of the polarizing plate 24 on the counter substrate 20 side is arranged in a direction perpendicular to the transmission axis of the polarizing plate 14 (a direction parallel to the alignment direction of the alignment films 18 and 28 in the transmission display region T).

  Although an arbitrary direction can be selected as the alignment direction, the direction intersects with the main directions EFt and EFr of the lateral electric field formed between the pixel electrode 9 and the common electrode 19 (a direction that does not coincide). . The relationship between the alignment direction and the horizontal electric field direction can be appropriately selected according to the retardation of the liquid crystal layer 50 and the optical axis arrangement of the polarizing plates 14 and 24. In the case of the present embodiment, the horizontal direction in the transmissive display region T is selected. The electric field direction EFt is parallel to the Y-axis direction, and the transverse electric field direction EFr in the reflective display region R is a direction inclined by approximately 45 ° with respect to the Y-axis.

  The liquid crystal device 100 having the above-described configuration is an IPS liquid crystal device, and an image signal (voltage) is applied to the pixel electrode 9 via the TFT 30, whereby the substrate surface is interposed between the pixel electrode 9 and the common electrode 19. An electric field in the direction is generated, the liquid crystal is driven by the electric field, and image display is performed by changing the transmittance / reflectance for each sub-pixel.

  Next, the display operation of the liquid crystal device 100 will be described. As shown in FIG. 5A, in a state where no voltage is applied to the pixel electrode 9, the liquid crystal molecules 51 constituting the liquid crystal layer 50 are denoted by reference numeral 151 in the transmissive display area T and denoted by reference numeral 152 in the reflective display area R. Each is oriented along the direction. As described above, since the alignment films 18 and 28 facing each other with the liquid crystal layer 50 interposed therebetween are aligned in the same direction in plan view, the liquid crystal molecules 51 are horizontally aligned in one direction between the substrates. When an electric field is applied to the liquid crystal layer 50 in such an alignment state via the pixel electrode 9 and the common electrode 19, the width of the strip electrodes 9c and 19c in the transmissive display region T as shown in FIG. The electric field EFt along the direction (Y-axis direction) acts, and the liquid crystal molecules 51 are aligned along the Y-axis direction. On the other hand, in the reflective display region R, since the extending direction of the strip electrodes 9d and 19d is different from the strip electrodes 9c and 19c of the transmissive display region T, an electric field EFr in a direction different from the transmissive display region T is formed. The liquid crystal molecules 51 are aligned along that direction.

  The liquid crystal device 100 performs bright and dark display using birefringence based on the difference in the alignment state of the liquid crystal molecules 51, and further, when a voltage is applied between the transmissive display region T and the reflective display region R. By varying the operation of the liquid crystal molecules 51, appropriate transmittance / reflectance can be obtained in each region. Further, since light leakage is likely to occur at the boundary between the transmissive display region T and the reflective display region R due to disorder of orientation or the like, the light in that portion is shielded by the light shielding layer 60, and black display is always performed.

  As described above, in the liquid crystal device 100 of the present embodiment, the initial alignment state of the liquid crystal and the direction in which the electric field is applied are different between the transmissive display region T and the reflective display region R, and the voltage is applied to the pixel electrode 9 (selected state). The phase difference imparted to the light transmitted through the liquid crystal layer 50 is made different between the transmissive display region T and the reflective display region R. For this reason, the difference in display quality between the transmissive display and the reflective display due to the optical path difference between the transmissive display area T and the reflective display area R can be eliminated, and high-quality display is performed in both the transmissive display and the reflective display. be able to.

  In addition, since the alignment state of the transmissive display region T and the reflective display region R is controlled by using the optical alignment technique, dust adhesion, generation of static electricity, and the like compared to the case where contact type alignment processing such as rubbing is used. The TFT is not damaged by this. Further, the alignment division can be easily performed by changing the polarization direction of the irradiated light for each alignment region.

  Further, when the alignment processing is made different between the transmissive display region T and the reflective display region R, positional displacement occurs in the alignment processing, and display defects such as black and white inversion occur at the boundary between the transmissive display region T and the reflective display region R. Although there is a possibility, in this embodiment, since the light shielding layer 60 is provided at the boundary portion, it is possible to reliably prevent a decrease in contrast due to light leakage from the boundary portion. In addition, when a plurality of alignment regions having different alignment directions are provided in the alignment film, disorder of alignment may occur at the boundary portion, and light leakage may occur. Can be shielded from light.

  In addition, since the multi-gap structure is not employed, there is little alignment disorder occurring at the boundary between the transmissive display region T and the reflective display region R. In other words, when a multi-gap structure is formed in the sub-pixel region, a region where the liquid crystal layer thickness continuously changes is formed at the boundary between regions having different liquid crystal layer thicknesses, so that the alignment of liquid crystal molecules is disturbed in the boundary region. However, in the liquid crystal device 100 of this embodiment, such a problem does not occur, and a display with high contrast can be realized.

  In the present embodiment, an IPS (In-Plane Switching) method is used among horizontal electric field methods in which an image is displayed by applying an electric field (lateral electric field) in a substantially substrate plane direction to liquid crystal and controlling the orientation. Although the present invention is applied to a so-called system, the present invention can also be applied to a system called an FFS (Fringe Field Switching) system as a system for displaying an image on the same principle.

  The FFS method is a method in which the pixel electrode and the common electrode are provided in different layers, and the alignment of the liquid crystal is controlled by using a lateral electric field generated between the fringe portion of the pixel electrode formed in a comb shape and the common electrode. . In the FFS method, the common electrode is a solid electrode and is provided in a layer between the pixel electrode and the reflective layer. In an IPS liquid crystal device, when a reflective layer is provided on a substrate on which a pixel electrode and a common electrode are provided, the reflective layer formed by a metal film is usually formed between the pixel electrode and the common electrode. In the FFS method, since the common electrode is a solid conductive film, even if a reflective layer is provided on the substrate on which the pixel electrode and the common electrode are provided, the electric field There is no impact. Further, since the patterning of the electrodes is only the pixel electrodes, the manufacturing is facilitated and the yield is improved.

  In the liquid crystal device 100, the multi-gap structure is not adopted. However, the liquid crystal layer thickness adjusting layer (multi-gap structure) is arranged in the reflective display region R, and the liquid crystal layers of the transmissive display region T and the reflective display region R are arranged. The present invention can also be applied to liquid crystal devices having different thicknesses. Furthermore, although the TFT 30 is used as the pixel switching element, a two-terminal nonlinear element such as a TFD (Thin Film Diode) can be used as the switching element, and the present invention is applied to a simple matrix type liquid crystal device that does not use the pixel switching element. The invention can also be applied.

Further, in the present embodiment, the present invention is applied to a transflective liquid crystal device in which the alignment process is different between the reflective display region R and the transmissive display region T as an example of a liquid crystal device in which the alignment of the liquid crystal varies from region to region. However, the liquid crystal device to which the present invention is applied is not limited to such an example, and the present invention can also be applied to a transmissive or reflective liquid crystal device having a multi-domain structure. For example, in a TN type liquid crystal device, the present invention can be applied when it is desired to change the clear viewing direction of the reflective display and the transmissive display, whereby the visibility is high in both the transmissive display and the reflective display, and the contrast characteristics are improved. In addition, an excellent liquid crystal device can be provided.
[Electronics]
Next, an electronic device provided with a liquid crystal device according to the present invention in a display portion will be described. FIG. 6 is a perspective configuration diagram of a mobile phone which is an example of the electronic apparatus. This cellular phone 1300 includes the liquid crystal device of the present invention as a small-sized display portion 1301, and includes a plurality of operation buttons 1302, an earpiece 1303, and a mouthpiece 1304. Therefore, high luminance, high contrast, wide viewing angle transmission display and reflection display are possible.

  The liquid crystal device of the above embodiment is not limited to the mobile phone, but an electronic book, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type or a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic notebook, It can be suitably used as an image display means for devices such as calculators, word processors, workstations, videophones, POS terminals, touch panels, etc. In any electronic device, high luminance, high contrast, wide viewing angle transmission display And reflective display is possible.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

It is a circuit block diagram of the liquid crystal device which concerns on one Embodiment of this invention. 2 is a plan configuration diagram of one sub-pixel region of the liquid crystal device. FIG. FIG. 3 is a cross-sectional configuration diagram taken along line A-A ′ of FIG. 2. It is a schematic perspective view which shows an example of the polarization exposure apparatus used for the alignment process of the liquid crystal device. FIG. 6 is an explanatory diagram of operations of the liquid crystal device. It is a perspective block diagram which shows an example of the electronic device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 9 ... Pixel electrode (first electrode), 9c, 9d ... Strip electrode, 10 ... TFT array substrate (first substrate), 18 ... Alignment film, 18A ... Alignment film material, 19 ... Common electrode (second electrode), 19c , 19d ... strip electrode, 20 ... counter substrate (second substrate), 28 ... alignment film, 50 ... liquid crystal layer, 51 ... liquid crystal, 60 ... light shielding layer, 100 ... liquid crystal device, 1300 ... mobile phone (electronic device), EFr , EFt ... transverse electric field, R ... reflective display area, T ... transmissive display area

Claims (7)

A first substrate provided with a first electrode and a second electrode;
A second substrate facing the first substrate;
A liquid crystal sandwiched between the first substrate and the second substrate and driven by an electric field generated between the first electrode and the second electrode;
An alignment film provided on the liquid crystal side surface of the first substrate and the second substrate;
A plurality of alignment regions provided on the alignment film and aligning liquid crystals in different directions;
A liquid crystal device comprising: a light shielding layer provided so as to overlap a boundary portion between alignment regions having different alignment directions.   The plurality of alignment regions are formed by a photo-alignment process that irradiates light to the alignment film material forming the alignment film and induces rearrangement or anisotropic chemical reaction in the molecules of the alignment film material. The liquid crystal device according to claim 1.   3. The liquid crystal device according to claim 1, wherein the alignment regions having different alignment directions correspond to a reflective display region for performing reflective display and a transmissive display region for performing transmissive display, respectively. Each of the first electrode and the second electrode includes one or a plurality of strip electrodes,
The strip electrode of the first electrode and the strip electrode of the second electrode are arranged in parallel with each other in each of the reflective display region and the transmissive display region,
The liquid crystal device according to claim 3, wherein an extending direction of the strip electrode in the reflective display region and an extending direction of the strip electrode in the transmissive display region are different from each other.   The liquid crystal device according to claim 1, wherein the light shielding layer is provided on the second substrate.   The liquid crystal device according to claim 5, wherein the light shielding layer is made of metal. An electronic apparatus comprising the liquid crystal device according to claim 1.

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