JP2006276112A - Liquid crystal device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transverse electric field type transreflective liquid crystal device capable of obtaining display of high quality on both of reflective display and transparent display. <P>SOLUTION: The transreflective liquid crystal device provided with a TFT array substrate 10 and a counter substrate 20 which are opposed to each other through a liquid crystal layer 50 is a transreflective type reflecting/polarizing layer, where a common electrode 19 (first electrode) comprising a reflective common electrode (reflective polarizing layer) 19r and a transparent common electrode 19t, an inter-layer insulating film 13 covering the common electrode 19 and a pixel electrode (second electrode) 9 formed on the inter-layer insulating film 13 are formed on the TFT array substrate 10. The reflective common electrode 19r has a transmission axis and a reflection axis intersecting with the transmission axis, reflects polarized component light parallel with the reflection axis out of light made incident on the reflective common electrode 19r and transmits polarized component light parallel with the transmission axis. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

As one form of a liquid crystal device, there is known a method of controlling the alignment of liquid crystal molecules by applying an electric field in the substrate surface direction to a liquid crystal layer (hereinafter referred to as a transverse electric field method), and applying an electric field to the liquid crystal. There are known what are called an IPS (In-Plane Switching) system, an FFS (Frige-Field Switching) system, etc., depending on the form of electrodes to be used (see, for example, Patent Document 1).
JP 2003-131248 A

By the way, since a portable information terminal such as a cellular phone is used in various environments, a transflective liquid crystal device is used for its display unit. Therefore, the present inventor has studied a transflective liquid crystal device of a type in which liquid crystal is driven by a horizontal electric field. In the IPS mode or FFS mode liquid crystal device, a reflective layer is partially formed in the pixel region. It was found that transflective display could not be performed even if provided.
Accordingly, it is an object of the present invention to provide a transflective liquid crystal device of a horizontal electric field type capable of obtaining a high quality display in both a reflective display and a transmissive display.

  In order to solve the above problems, the present invention includes a first substrate and a second substrate that are opposed to each other with a liquid crystal layer interposed therebetween, and a transflective liquid crystal that performs reflection display and transmission display in one dot region. A device comprising: a first electrode formed in the dot region on the first substrate; an interlayer insulating film covering the first electrode; and the first electrode formed on the interlayer insulating film; A second electrode for generating an electric field in a substantially plane direction of the substrate, and a reflective polarizing layer, the reflective polarizing layer having a transmission axis and a reflection axis intersecting the transmission axis, It is a transflective reflective polarizing layer that reflects light having a polarization component parallel to the reflection axis and transmits light having a polarization component parallel to the transmission axis among light incident on the reflective polarization layer. Provided is a liquid crystal device.

  This liquid crystal device is a horizontal electric field type liquid crystal device adopting an FFS method in which an electric field in the direction of a substantially substrate surface formed between a first electrode and a second electrode is applied to a liquid crystal layer to drive the liquid crystal. In the liquid crystal device of the present invention, by providing a transflective reflective polarizing layer, both transmissive display and reflective display are good, and a horizontal electric field type transflective liquid crystal using a simple configuration is provided. The device can be realized. Further, according to the present invention, it is possible to obtain a display with high brightness and high contrast in both reflection display and transmission display without adopting a conventionally known multi-gap structure as a configuration of a transflective liquid crystal device. .

  In this specification, for example, the color liquid crystal display device corresponds to the case where one pixel is configured by three dots of R (red), G (green), and B (blue), and the display is configured. The display area that is the minimum unit to be performed is referred to as a “dot area”. Further, the “reflective display area” provided in the dot area refers to an area capable of display using light incident from the display surface side of the liquid crystal display device, and the “transmissive display area” refers to the liquid crystal display. A region where display using light incident from the back side of the device (opposite to the display surface) is possible.

  In the liquid crystal device of the present invention, the reflective polarizing layer may be partially formed in the dot region. In the liquid crystal device having such a configuration, the reflective display area is configured by the area where the reflective polarizing layer is partially formed in the dot area, and the transmissive display area is configured by the remaining non-formed area. In this case, since the transmissive display area and the reflective display area are clearly divided, the optical design can be optimized in each of the reflective display and the transmissive display, which is advantageous in obtaining a higher-quality liquid crystal device. .

  In the liquid crystal device of the present invention, the reflective polarizing layer may be formed on substantially the entire surface of the dot region. In the liquid crystal device having such a configuration, the reflective polarizing layer partially transmits the incident polarization component and reflects a part of the polarization component. Since the reflective polarizing layer can be formed in a solid shape within the dot region, the structure is excellent in terms of ease of manufacturing and yield. Further, as compared with the case where the dot area is divided into a reflective display area and a transmissive display area, the area can be widely used, and the optical design of the pixel is facilitated.

  In the liquid crystal device of the present invention, the reflective polarizing layer may include a prism array in which a plurality of prisms are formed and a dielectric interference film formed on the prism array. The reflective polarizing layer having such a configuration can easily adjust the reflectance and transmittance by the laminated structure of the dielectric interference film, and is particularly used for the configuration in which the reflective polarizing layer is provided on the entire surface of the dot region. Is preferred.

  In the liquid crystal device of the present invention, the reflective polarizing layer may include a metal reflective film provided with a plurality of fine slit-shaped openings. The reflective polarizing layer having such a configuration has the advantage that the degree of polarization is high and the patterning is easy as compared with the configuration in which the dielectric interference film is formed on the prism array. Therefore, it is a reflective polarizing layer suitable for use in a configuration in which a reflective polarizing layer is partially provided in the dot region.

  In the liquid crystal device of the present invention, the reflective polarizing layer may be electrically connected to the first electrode. With such a configuration, the reflective polarizing layer can be used as part of an electrode for applying a voltage to the liquid crystal.

  The liquid crystal device according to the present invention is characterized in that a layer thickness of the liquid crystal layer is substantially uniform in the dot region. In the liquid crystal device of the present invention, since the multi-gap structure is not used, the layer thickness of the liquid crystal layer can be made uniform in the dot region, so that the driving voltage varies greatly depending on the liquid crystal layer thickness. In this liquid crystal device, it is possible to prevent the drive voltage from becoming uneven in the dot region, and to obtain high-quality transmissive display and reflective display.

  In the liquid crystal device of the present invention, an illumination device is disposed on the outer surface side of the first substrate. In the liquid crystal device of the present invention, the first substrate is provided with a reflective polarizing layer for performing reflective display, and a first electrode and a second electrode for driving the liquid crystal. A liquid crystal device that is not arranged in the above can be configured. When the first substrate is disposed on the display surface side, external light is irregularly reflected by a metal wiring or the like formed on the first substrate to supply a driving signal to the first electrode or the second electrode, and the liquid crystal device However, in the present invention, such irregular reflection of external light does not occur, and excellent visibility can be obtained.

  In the liquid crystal device of the present invention, a polarizing plate is provided between the first substrate and the illumination device, and the transmission axis of the polarizing plate is arranged in a direction substantially orthogonal to the transmission axis of the reflective polarizing layer. It is preferable. With such a configuration, the utilization efficiency of the illumination light incident from the illumination device can be maximized, and a bright transmissive display can be obtained.

  In the liquid crystal device of the present invention, a color filter is provided on either the first substrate or the second substrate, and the color filter is partitioned into a plurality of planar regions having different chromaticities within the dot region. can do. According to this configuration, it is possible to perform color display with appropriate chromaticity in each of the reflective display region and the transmissive display region, and a liquid crystal device with more colorful and high image quality can be obtained.

  Next, an electronic apparatus according to the present invention includes the liquid crystal device according to the present invention described above. According to this configuration, it is possible to provide an electronic apparatus including a display unit that can perform transmissive display and reflective display with high brightness, high contrast, and a wide viewing angle.

(First embodiment)
Hereinafter, a liquid crystal device according to a first embodiment of the present invention will be described with reference to the drawings. The liquid crystal device according to the present embodiment is called an FFS (Fringe Field Switching) method among horizontal electric field methods in which an image is displayed by applying an electric field (lateral electric field) in the direction of the substrate surface to the liquid crystal and controlling the alignment. This is a liquid crystal device that employs this method. The liquid crystal device according to the present embodiment is a color liquid crystal device having a color filter on a substrate, one for each of three dots that output light of each color of R (red), G (green), and B (blue). This constitutes the pixel. Therefore, a display area that is a minimum unit that constitutes a display is referred to as a “dot area”, and a display area that is composed of a set of (R, G, B) dots is referred to as a “pixel area”.

FIG. 1 is a circuit configuration diagram of a plurality of dot regions formed in a matrix that constitutes the liquid crystal device of the present embodiment. 2A is a plan configuration diagram in an arbitrary one-dot region of the liquid crystal device 100, and FIG. 2B is an explanatory diagram showing an arrangement relationship of optical axes of each optical element constituting the liquid crystal device 100. FIG. . FIG. 3 is a partial cross-sectional configuration diagram taken along the line AA ′ of FIG.
In each drawing, each layer and each member are displayed in different scales so that each layer and each member can be recognized on the drawing.

  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 dot regions formed in a matrix forming the image display region 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. 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. The TFT array substrate 10 and the counter substrate 20 are sealed between the substrates 10 and 20 by a seal material (not shown) provided along an edge of a 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 and a reflecting plate 92 is provided on the back side (the lower side in the drawing) of the TFT array substrate 10.

As shown in FIG. 2, the dot region of the liquid crystal device 100 includes a pixel electrode (second electrode) 9 that is substantially rake-like (comb-like) in plan view and that is long in the Y-axis direction. And a common electrode (first electrode) 19 having a substantially flat surface arranged in a plane. A columnar spacer 40 is erected on the upper left corner of the dot area to hold the TFT array substrate 10 and the counter substrate 20 at a predetermined interval.
The pixel electrode 9 is connected to a plurality (five in the drawing) of pixel electrode portions 9c extending in the Y-axis direction, and ends on the + Y side of the plurality of pixel electrode portions 9c, and extends in the X-axis direction. It consists of a base end portion 9a and a contact portion 9b extending to the + Y side from the central portion in the X-axis direction of the base end portion 9a.

  The common electrode 19 is partitioned into a transparent common electrode 19t and a reflective common electrode 19r in the pixel region shown in FIG. 2, and the transparent common electrode 19t and the reflective common electrode 19r extending in the X-axis direction in the entire image display region. Are arranged alternately in the Y-axis direction. In the case of this embodiment, the transparent common electrode 19t is a conductive film made of a transparent conductive material such as ITO (indium tin oxide), and the reflective common electrode 19r is a light having a fine slit structure, as will be described in detail later. It is a reflective polarizing layer made of a reflective metal film.

  In the TFT 30, a data line 6a extending in the X-axis direction, a scanning line 3a extending in the Y-axis direction, and a capacitor line 3b extending in parallel with the scanning line 3a adjacent to the scanning line 3a are formed. A TFT 30 is provided in the vicinity of the intersection of the data line 6a and the scanning line 3a. The TFT 30 includes a semiconductor layer 35 made of amorphous silicon partially formed in a planar region of the scanning line 3a, a source electrode 6b formed partially overlapping the semiconductor layer 35, and a drain electrode 32. ing. 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 6b of the TFT 30 is formed in a substantially inverted L shape in plan view extending from the data line 6a and extending to the semiconductor layer 35. The drain electrode 32 extends to the −Y side and is a capacitive electrode having a substantially rectangular shape in plan view. 31 is electrically connected. The capacitor electrode 31 has a contact portion 9b of the pixel electrode 9 extending from the −Y side, and a pixel contact hole 45 is provided at a position where the two overlap in a plane. The capacitor electrode 31 and the pixel electrode 9 are electrically connected through the pixel contact hole 45.
The capacitor electrode 31 is disposed in the planar region of the capacitor line 3b, and a storage capacitor 70 is formed using the capacitor electrode 31 and the capacitor line 3b that are opposed in the thickness direction as electrodes.

  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. The TFT array substrate 10 has a translucent substrate body 10A made of glass, quartz, plastic, or the like as a base, and scanning lines 3a and capacitance lines 3b are formed on the inner surface side (the liquid crystal layer 50 side) of the substrate body 10A. A gate insulating film 11 made of a transparent insulating film such as silicon oxide is formed so as to cover the scanning lines 3a and the capacitor lines 3b.

An amorphous silicon semiconductor layer 35 is formed on the gate insulating film 11, and a source electrode 6 b and a drain electrode 32 are provided so as to partially run over the semiconductor layer 35. A capacitive electrode 31 is integrally formed on the + X side of the drain electrode 32. The semiconductor layer 35 is disposed to face 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 is disposed opposite to the capacitor line 3b via the gate insulating film 11, and the storage capacitor 70 using the gate insulating film 11 as a dielectric film in a region where the capacitor electrode 31 and the capacitor line 3b are opposed to each other. Is formed.

  A first interlayer insulating film 12 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 transparent such as ITO is formed on the first interlayer insulating film 12. A common electrode 19 is formed which includes a transparent common electrode 19t made of a conductive material and a reflective common electrode (reflective polarizing layer) 19r mainly made of a reflective metal film such as aluminum. Therefore, in the liquid crystal device 100 of the present embodiment, the area where the plane area of the transparent common electrode 19t and the plane area including the pixel electrode 9 overlap in the one dot area shown in FIG. This is a transmissive display region T for performing display by modulating light incident from the light 90 and transmitted through the liquid crystal layer 50. In addition, a region where the planar region of the reflective common electrode 19r overlaps with the planar region including the pixel electrode 9 reflects and modulates light that is incident from the outside of the counter substrate 20 and is transmitted through the liquid crystal layer 50, thereby performing display. This is the reflective display area R to be performed.

  FIGS. 2 and 3 show a case where the transparent common electrode 19t and the reflective common electrode 19r constituting the common electrode 19 are partitioned in a plane, but the transparent common electrode 19t is commonly used for reflection. It may extend so as to cover the electrode 19r. With such a configuration, since the transparent common electrode 19t is uniformly disposed on the surface of the common electrode 19 facing the pixel electrode 9, the electric field generated between the pixel electrode 9 and the common electrode 19 is reduced. It is possible to make uniform within the dot area.

  A second interlayer insulating film 13 made of silicon oxide or the like is formed so as to cover the common electrode 19, and a pixel electrode 9 made of a transparent conductive material such as ITO is formed on the second interlayer insulating film 13. A pixel contact hole 45 that penetrates the first interlayer insulating film 12 and the second interlayer insulating film 13 and reaches the capacitor electrode 31 is formed, and a contact portion 9 b of the pixel electrode 9 is partially embedded in the pixel contact hole 45. As a result, the pixel electrode 9 and the capacitor electrode 31 are electrically connected. The common electrode 19 is also provided with an opening corresponding to the region where the pixel contact hole 45 is formed, so that the common electrode 19 and the pixel electrode 9 are not in contact with each other. An alignment film 18 made of polyimide or the like is formed in a region on the second interlayer insulating film 13 covering the pixel electrode 9.

On the other hand, a color filter 22 and an alignment film 28 are laminated on the inner surface side (liquid crystal layer 50 side) of the counter substrate 20, and a polarizing plate 24 is provided on the outer surface side of the counter substrate 20. In addition to the polarizing plate 24, a retardation plate and other optical elements can be provided on the outer surface 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 pixel region. Specifically, the color filter 22 corresponds to a planar region of the transparent common electrode 19t constituting the transmissive display region. The first color material region is provided, the second color material region is provided corresponding to the planar region of the reflective common electrode 19t constituting the reflective display region, and the chromaticity of the first color material region is A configuration that 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 area where the display light is transmitted only once through the color filter 22 and the reflective display area where the display light is transmitted twice. Display quality can be improved by making the display and the transparent display look the same.

Here, FIG. 4 is a diagram for explaining the configuration and operation of the reflective common electrode 19r, which is a reflective polarizing layer, and FIG. 4 (a) is a plan configuration diagram of the reflective common electrode 19r, and FIG. 4 (b). These are side surface block diagrams which follow the JJ 'line | wire of Fig.4 (a).
As shown in FIGS. 4A and 4B, the reflective common electrode 19r is mainly composed of a light-reflective metal film 71 such as aluminum, and a plurality of stripes in plan view are formed on the metal film 71 at a predetermined pitch. The fine slit 72 is formed. The plurality of slits 72 are formed in parallel with each other and have the same width. The width of the slit 72 is about 30 nm to 300 nm, and the line width of the metal film 71 that is linear as a result of the formation of the plurality of slits 72 at a predetermined pitch is about 30 nm to 300 nm.

  As shown in FIG. 4B, the reflective common electrode 19r having the above configuration reflects the polarized light component parallel to the length direction of the slit 72 as reflected light Er when light E is incident from the upper surface side. Then, the polarization component parallel to the width direction of the slit 72 is transmitted as transmitted light Et. That is, the reflection common electrode 19r has a reflection axis parallel to the extending direction of the slit 72 and a transmission axis in a direction perpendicular to the reflection axis.

As shown in the arrangement diagram of the optical axis in FIG. 2B, the reflection common electrode 19r has a transmission axis (direction orthogonal to the extending direction of the slit 72) 157 in the liquid crystal device 100. The polarizing plate 24 is arranged so as to be parallel to the transmission axis 153 of the polarizing plate 24 and is arranged in a direction orthogonal to the transmission axis of the polarizing plate 14 on the TFT array substrate 10 side. In the liquid crystal device 100 of this embodiment, the alignment films 18 and 28 are rubbed in the same direction in plan view, and the direction is a rubbing direction 151 shown in FIG. Therefore, the transmission axis 157 of the reflective common electrode 19r and the rubbing direction 151 of the alignment films 18 and 28 are arranged in parallel.
The rubbing direction 151 forms an angle of about 30 ° with respect to the pixel electrode portions 9c extending in parallel with the pixel arrangement direction (Y-axis direction) of the liquid crystal device 100.

The liquid crystal device 100 having the above-described configuration is an FFS liquid crystal device, and an image signal (voltage) is applied to the pixel electrode 9 through the TFT 30 so that the substrate surface is interposed between the pixel electrode 9 and the common electrode 19. An electric field in the direction (X-axis direction in FIG. 2 in plan view) is generated, the liquid crystal is driven by the electric field, and the transmittance / reflectance for each dot is changed to display an image. As shown in FIG. 2B, since the alignment films 18 and 28 facing each other with the liquid crystal layer 50 interposed therebetween are rubbed in the same direction in plan view, in a state where no voltage is applied to the pixel electrode 9, Liquid crystal molecules constituting the liquid crystal layer 50 are horizontally aligned between the substrates 10 and 20 along the rubbing direction 151. When an electric field formed between the pixel electrode 9 and the common electrode 19 is applied to the liquid crystal layer 50, the line width direction (X-axis direction) of the pixel electrode portion 9c shown in FIG. The liquid crystal molecules are aligned. The liquid crystal device 100 performs bright and dark display using birefringence based on the difference in the alignment state of liquid crystal molecules.
Note that the common electrode 19 only needs to be held at a constant voltage so as to cause a voltage difference within a predetermined range with the pixel electrode 9 during the operation of the liquid crystal device 100, but is synchronized with the scanning pulse input to the scanning line 3a. A pulse signal may be input.

  Next, the operation of the liquid crystal device 100 having the above configuration will be described with reference to FIG. FIG. 5 is an operation explanatory diagram of the liquid crystal device 100. In FIG. 3, only the components necessary for explanation are extracted from the components shown in FIG. 3, and the polarizing plate 24, the liquid crystal layer 50, the common electrode 19, and the polarization are sequentially shown from the upper side in the drawing. A plate 14 and a backlight 90 are shown.

First, the transmissive display (transmission mode) on the right side of FIG. 5 will be described.
In the liquid crystal device 100, the light emitted from the backlight 90 passes through the polarizing plate 14, is converted into linearly polarized light parallel to the transmission axis 155 of the polarizing plate 14, and enters the common electrode 19. Of these, the light passes through the transparent common electrode 19 t and enters the liquid crystal layer 50. If the liquid crystal layer 50 is in an on state (a selection voltage is applied between the pixel electrode 9 and the common electrode 19), the incident light has a predetermined phase difference (λ / 2) by the liquid crystal layer 50. And is converted into linearly polarized light parallel to the transmission axis 153 of the polarizing plate 24. Thereby, the light transmitted through the polarizing plate 24 is visually recognized as display light, and the dot is brightly displayed.

On the other hand, if the liquid crystal layer 50 is in an off state (a state where the selection voltage is not applied), incident light reaches the polarizing plate 24 while maintaining its polarization state, and an absorption axis (transmission axis) parallel to the incident light. The dots are absorbed by the polarizing plate 24 having an optical axis orthogonal to 153, and the dots are darkly displayed.
Note that the light that has passed through the polarizing plate 14 and entered the reflective common electrode 19r is reflected by the reflective common electrode 19r having a reflection axis parallel to the linearly polarized light, so that the backlight 90 does not enter the liquid crystal layer 50. Back to the side.

Next, the reflective display on the left side of FIG. 5 will be described.
In the reflective display, light incident from above (outside) the polarizing plate 24 is transmitted through the polarizing plate 24 to be converted into linearly polarized light parallel to the transmission axis 153 of the polarizing plate 24 and is incident on the liquid crystal layer 50. At this time, if the liquid crystal layer 50 is in an ON state, the incident light is given a predetermined phase difference (λ / 2) by the liquid crystal layer 50 and is incident on the reflective common electrode 19r. As shown in FIG. 2B, the reflection common electrode 19r, which is a reflection polarizing layer, has a transmission axis 157 parallel to the transmission axis 153 of the polarizing plate 14 and a reflection axis orthogonal to the transmission axis 153. Light that has passed through the liquid crystal layer 50 in the on state and entered the reflective common electrode 19r is reflected while maintaining its polarization state. The reflected light incident on the liquid crystal layer 50 again returns to the polarization state at the time of incidence (linearly polarized light parallel to the transmission axis of the polarizing plate 24) by the action of the liquid crystal layer 50 and enters the polarizing plate 24. As a result, the reflected light transmitted through the polarizing plate 24 is visually recognized as display light, and the dot is brightly displayed.

  On the other hand, if the liquid crystal layer 50 is in the off state, the light incident on the liquid crystal layer 50 from the polarizing plate 24 enters the reflective common electrode 19r while maintaining the polarization state, and has a transmission axis 157 parallel to the light. It passes through the reflective common electrode 19r. Then, the dots are absorbed by the polarizing plate 14 having an absorption axis parallel to the light, and the dots are darkly displayed.

  Here, FIG. 6 is an operation explanatory diagram of the liquid crystal device 1000 having a configuration in which a metal reflective film 190 such as aluminum is partially provided in the dot region in the FFS mode liquid crystal device. That is, the liquid crystal device 1000 is a combination of an FFS type liquid crystal device and a conventionally known transflective liquid crystal device, and the formation region of the metal reflective film 190 in the dot region is used as a reflective display region. In this configuration, the formation region of the opening 190t formed in the metal reflective film 190 is assumed to be a transmissive display region.

  As shown in FIG. 6, the liquid crystal device 1000 can perform bright and dark display similar to the liquid crystal device 100 according to the embodiment in the transmissive display. However, in the reflective display, the display is bright regardless of whether the liquid crystal layer 50 is on or off, and cannot be displayed normally. In the liquid crystal device 1000, a retardation plate (λ / 4 plate) may be provided between the polarizing plate 24 and the liquid crystal layer 50 so that circularly polarized light is incident on the liquid crystal layer 50 during reflection display. In the horizontal electric field type liquid crystal device that is aligned in parallel, the phase difference value of the liquid crystal layer 50 is not changed by the electric field response as in the conventional vertical electric field method, but the in-plane direction of the optical axis of the liquid crystal layer 50 is changed. Therefore, it is difficult to apply such a circular polarization mode in order to realize high display quality. In the case of circularly polarized light, when the phase difference provided by the liquid crystal layer 50 is approximately λ / 2, the light is emitted from the liquid crystal layer 50 in the same polarization state without depending on the direction of the optical axis of the liquid crystal layer 50. is there. In addition, when the phase difference provided by the liquid crystal layer 50 is other than approximately λ / 2, it is difficult to achieve both high display quality in reflective display and transmissive display.

  As the transflective liquid crystal device, a so-called multi-gap transflective liquid crystal device in which the liquid crystal layer thickness of the reflective display region is about half of the liquid crystal layer thickness of the transmissive display region is also known. In a horizontal electric field type liquid crystal device, the driving voltage varies greatly depending on the thickness of the liquid crystal layer, so even if a multi-gap structure is applied, display quality deterioration due to the driving voltage difference between the reflective display area and the transmissive display area can be avoided. Therefore, it is difficult to obtain a high-quality transflective display.

  On the other hand, the liquid crystal device 100 of the present embodiment employs a configuration in which a reflective polarizing layer (reflective common electrode 19r) is partially provided in the dot region, so that a circularly polarized mode or a multi-gap structure is used. Therefore, a high-contrast reflective display and transmissive display can be obtained, and a high-quality transflective liquid crystal device can be realized with a simple configuration. In addition, since the liquid crystal layer thickness in the dot area is constant, there is no difference in driving voltage between the transmissive display area T and the reflective display area R, and the display state differs between the reflective display and the transmissive display. There is no.

  Further, in the liquid crystal device 100 of the present embodiment, the reflective common electrode 19r for performing the reflective display is provided on the TFT array substrate 10 side, and therefore, with the metal wiring or the like formed on the TFT array substrate 10 together with the TFT 30. It can prevent effectively that external light is reflected and display quality is reduced. Furthermore, since the pixel electrode 9 is formed using a transparent conductive material, it is possible to prevent external light that has passed through the liquid crystal layer 50 and entered the TFT array substrate 10 from being irregularly reflected by the pixel electrode 9. Excellent visibility can be obtained.

  In addition, the reflective common electrode 19r used in the present embodiment is narrow because it can be accurately formed only by forming an aluminum film on the interlayer insulating film 12 and then patterning the aluminum film using a photolithography technique. It can also be suitably used for a high-definition liquid crystal device having a dot region.

(Second Embodiment)
Next, a liquid crystal device according to a second embodiment of the present invention will be described with reference to FIGS.
FIG. 7A is a plan configuration diagram showing an arbitrary one-dot region in the liquid crystal device 200 of the present embodiment, and FIG. 7B is an explanation showing the arrangement of optical axes of optical elements in the liquid crystal device. FIG. FIG. 8 is a cross-sectional configuration diagram taken along the line BB ′ of FIG. FIG. 9 is a diagram for explaining the configuration and operation of the reflective polarizing layer, and FIG. 10 is an operation explanatory diagram of the liquid crystal device 200 of the present embodiment.

  The basic configuration of the liquid crystal device 200 of the present embodiment is the same as that of the first embodiment, and FIGS. 7A and 7B are the same as FIGS. 2A and 2B in the first embodiment, respectively. FIGS. 8 and 10 are diagrams corresponding to FIGS. 3 and 5 in the first embodiment, respectively. Accordingly, in each drawing referred to in the present embodiment, the same components as those in the liquid crystal device 100 according to the first embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals, and the common components will be described below. Is omitted.

As shown in FIG. 7, a pixel electrode (second electrode) 9 and a TFT 30 electrically connected to the pixel electrode 9 through a capacitor electrode 31 are provided in the dot region of the liquid crystal device 200 of the present embodiment. It has been. A drain electrode 32 extending from the capacitor electrode 31 and a source electrode 6b branched from the data line 6a extending in the Y-axis direction in the figure are electrically connected to the amorphous silicon semiconductor layer 35 constituting the TFT 30. The gate electrode of the TFT 30 is configured at a position where the scanning line 3 a extending in the X-axis direction in the drawing on the back side of the layer 35 overlaps the semiconductor layer 35 in a plane. The capacitor electrode 31 and the capacitor line 3b extending in the X-axis direction while overlapping the capacitor electrode 31 in a plane form a storage capacitor 70 in the dot region.
In the dot region shown in FIG. 7A, a reflective polarizing layer 39 and a common electrode (first electrode) 29 each having a flat solid shape are provided.

  Referring to the cross-sectional structure shown in FIG. 8, the liquid crystal device 200 includes a TFT array substrate (first substrate) 10 and a counter substrate (second substrate) 20 that are opposed to each other with the liquid crystal layer 50 interposed therebetween. A backlight 90 is provided on the back side (the lower side in the figure) of the array substrate 10. Since the configuration of the counter substrate 20 is the same as that of the first embodiment, a detailed description thereof is omitted.

On the substrate body 10A that forms the base of the TFT array substrate 10, a flat solid reflective polarizing layer 39 is formed, and a common electrode 29 made of a transparent conductive material such as ITO is formed covering the reflective polarizing layer 39. . A first interlayer insulating film 12 is formed so as to cover the common electrode 29, and a scanning line 3 a and a capacitor line 3 b are formed on the first interlayer insulating film 12. A gate insulating film 11 is formed so as to cover the scanning line 3a and the capacitor line 3b. A semiconductor layer 35 is formed on the gate insulating film 11, and a source electrode 6b (data line 6a) electrically connected to the semiconductor layer 35, And the drain electrode 32 (capacitance electrode 31) is formed. A second interlayer insulating film 13 is formed so as to cover the semiconductor layer 35, the source electrode 6 b, the drain electrode 32, and the like, and the pixel electrode 9 is formed on the second interlayer insulating film 13. An alignment film 18 is formed so as to cover the pixel electrode 9.
A pixel contact hole 46 that penetrates through the second interlayer insulating film 13 and reaches the capacitor electrode 31 is formed, and the contact portion 9 b (pixel electrode 9) and the capacitor electrode 31 are electrically connected via the pixel contact hole 46. It is connected.

Here, FIG. 9A is a perspective configuration diagram of the reflective polarizing layer 39, and FIG. 9B is a side configuration diagram for explaining the operation of the reflective polarizing layer 39.
As shown in FIG. 9A, the reflective polarizing layer 39 provided in the liquid crystal device 200 of the present embodiment is made of a thermosetting or photocurable transparent resin such as an acrylic resin formed on the substrate body 10A. And a dielectric interference film 85 formed by alternately laminating two types of dielectric films having different refractive indexes.

The prism array 81 has a plurality of triangular prisms (prism-shaped) ridges 82 having two inclined surfaces, and the plurality of ridges 82 are formed continuously and periodically to form a triangular waveform. A prism array is configured. The dielectric interference film 85 is formed by alternately stacking dielectric films made of two kinds of materials having different refractive indexes so as to follow the inclined surfaces of the plurality of ridges 82 (so-called three-dimensional photonic crystal layer). For example, it can be formed by laminating seven layers of TiO ₂ films and SiO ₂ films alternately.

  Although not shown in FIG. 9, the upper surface of the dielectric interference film 85 is covered with a resin layer and flattened. As described above, the dielectric interference film 85 formed on the prism array has anisotropy in light propagation characteristics, and light (natural light) E is incident from the upper surface side in FIG. In this case, the polarization component parallel to the extending direction of the ridge 82 is reflected, and the polarization component perpendicular to the extending direction of the ridge 82 is transmitted. That is, the reflective polarizing layer 39 shown in FIGS. 7A and 8 has a reflection axis parallel to the extending direction of the ridges 82 and a transmission axis perpendicular to the extending direction of the ridges 82. become.

  In the liquid crystal device 200 of this embodiment, linearly polarized light parallel to the reflection axis of the reflective polarizing layer 39 is incident from the backlight 90 side to perform transmissive display. As shown in FIG. By arranging the transmission axis 155 of the polarizing plate 14 and the transmission axis 159 of the reflective polarizing layer 39 to be orthogonal to each other, the transmission axis 155 of the polarizing plate 14 and the reflective axis of the reflective polarizing layer 39 (the extension of the ridge 82) are arranged. Are arranged so as to be substantially parallel to each other. The transmission axis 153 of the polarizing plate 24 and the rubbing direction 151 of the alignment films 18 and 28 are arranged in parallel to the transmission axis of the reflective polarizing layer 39.

The film thickness of one dielectric film constituting the dielectric interference film 85 is about 10 nm to 100 nm, and the total film thickness of the dielectric interference film 85 is about 300 nm to 1 μm. The height of the ridges 82 of the prism array 81 is 0.5 μm to 3 μm, and the pitch between the adjacent ridges 82 and 82 is about 1 μm to 6 μm. As a material for the dielectric film, Ta ₂ O ₅ , Si, or the like can be used in addition to TiO ₂ and SiO ₂ .

  Note that the stacking pitch of the dielectric films constituting the dielectric interference film 85 and the pitch of the ridges 82 are appropriately adjusted to optimum values according to the characteristics of the target reflective polarizing layer 39. In other words, the reflective polarizing layer 39 having the above configuration can control the transmittance (reflectance) according to the number of laminated dielectric films constituting the dielectric interference film 85, and by reducing the number of laminated layers, the reflection axis ( The transmittance of linearly polarized light parallel to the extending direction of the ridges 82 can be increased, and the reflectance can be lowered. However, when a predetermined number or more of dielectric films are stacked, most of the linearly polarized light parallel to the reflection axis is reflected. The reflective polarizing layer 39 according to the present embodiment is set to reflect about 70% of the linearly polarized light parallel to the incident reflection axis and transmit the remaining about 30% by adjusting the dielectric interference film 85. ing.

  Next, the operation of the liquid crystal device 200 will be described with reference to FIG. In FIG. 10, the polarizing plate 24, the liquid crystal layer 50, the reflective polarizing layer 39, the polarizing plate 14, and the backlight 90, which are constituent elements necessary for the following operation description, are shown in order from the upper side in the figure.

First, the transmissive display (transmission mode) on the right side of FIG. 10 will be described.
In the liquid crystal device 200, the light emitted from the backlight 90 passes through the polarizing plate 14, is converted into linearly polarized light parallel to the transmission axis 155 of the polarizing plate 14, and enters the reflective polarizing layer 39. A part (approximately 30%) of this incident light, which is linearly polarized light parallel to the reflection axis 39 (optical axis orthogonal to the transmission axis 159), passes through the reflection polarization layer 39 and enters the liquid crystal layer 50. If the liquid crystal layer 50 is in an on state (a selection voltage is applied between the pixel electrode 9 and the common electrode 29), the incident light has a predetermined phase difference (λ / 2) by the liquid crystal layer 50. And is converted into linearly polarized light parallel to the transmission axis 153 of the polarizing plate 24. Thereby, the light transmitted through the polarizing plate 24 is visually recognized as display light, and the dot is brightly displayed.

On the other hand, if the liquid crystal layer 50 is in an off state (a state where the selection voltage is not applied), the light transmitted through the reflective polarizing layer 39 and incident on the liquid crystal layer 50 is maintained in the polarization state while maintaining the polarization state. And is absorbed by the polarizing plate 24 having an absorption axis parallel to the incident light (an optical axis orthogonal to the transmission axis 153), and the dots are darkly displayed.
Of the light that has passed through the polarizing plate 14 and entered the reflective polarizing layer 39, the light reflected by the reflective polarizing layer 39 is transmitted again through the polarizing plate 14 and returned to the backlight 90 side. Then, the return light is reflected by the reflecting plate 92 of the backlight 90 and becomes light again toward the liquid crystal panel, and is reused as illumination light.

Next, the reflective display on the left side of FIG. 10 will be described.
In the reflective display, light incident from above (outside) the polarizing plate 24 is transmitted through the polarizing plate 24 to be converted into linearly polarized light parallel to the transmission axis 153 of the polarizing plate 24 and is incident on the liquid crystal layer 50. At this time, if the liquid crystal layer 50 is in an ON state, the incident light is given a predetermined phase difference (λ / 2) by the liquid crystal layer 50 and enters the reflective polarizing layer 39. As shown in FIG. 8B, the reflective polarizing layer 39 has a transmission axis 159 parallel to the transmission axis 153 of the polarizing plate 14 and a reflection axis orthogonal to the transmission axis 153. A part of light (about 30%) that is transmitted through 50 and incident on the reflective polarizing layer 39 is reflected while maintaining the polarization state, and the remaining part (about 70%) is transmitted through the reflective polarizing layer 39. The light reflected by the reflective polarizing layer 39 and incident on the liquid crystal layer 50 again is returned to the polarization state at the time of incidence (linearly polarized light parallel to the transmission axis of the polarizing plate 24) by the action of the liquid crystal layer 50 and enters the polarizing plate 24. Incident. As a result, the reflected light transmitted through the polarizing plate 24 is visually recognized as display light, and the dot is brightly displayed.

  On the other hand, the linearly polarized light component transmitted through the reflective polarizing layer 39 is transmitted through the polarizing plate 14 having the transmission axis 155 parallel to the polarization direction and is incident on the backlight 90. The light incident on the backlight 90 is reflected by the reflecting plate 92 and returned to the liquid crystal layer 50 side, and part of the light is transmitted through the reflective polarizing layer 39 and incident on the liquid crystal layer 50. Used as display light. Therefore, in the liquid crystal device 200 of the present embodiment, the reflectance of linearly polarized light parallel to the reflection axis in the reflective polarizing layer 39 is set to about 30%, but is transmitted through the reflective polarizing layer 39 to the backlight 90 side. Since the light that has passed through can be used as display light, a bright reflective display can be obtained.

  On the other hand, if the liquid crystal layer 50 is in the off state, the light incident on the liquid crystal layer 50 from the polarizing plate 24 enters the reflective polarizing layer 39 while maintaining the polarization state, and has a transmission axis 159 parallel to the light. The reflective polarizing layer 39 is transmitted. Then, the dots are absorbed by the polarizing plate 14 having an absorption axis parallel to the light, and the dots are darkly displayed.

  In the liquid crystal device 200 having the above-described configuration, since the reflective polarizing layer 39 is formed in a flat solid shape on the substrate body 10A side of the pixel electrode 9, alignment with the dot region is unnecessary, and it can be performed in a simple process. There is an advantage that it can be formed at a cost. If the reflective polarizing layer 39 is provided on the substrate body 10A side of the semiconductor layer 35 as in the present embodiment, the pixel contact that electrically connects the wiring layer provided with the semiconductor layer 35 and the pixel electrode 9 to each other. The hole 46 can be formed shallowly, and the electrical reliability of the conductive connection structure through the pixel contact hole 46 can be improved. In addition, since the opening diameter of the pixel contact hole 46 can be reduced, liquid crystal alignment disorder caused by the pixel contact hole 46 can be suppressed.

  Further, similarly to the liquid crystal device 100 of the first embodiment, since the layer thickness of the liquid crystal layer 50 is constant in the dot area, the driving voltage does not become uneven in the dot area, and a high-quality display is achieved. Can be obtained. Further, since it is not necessary to form a step in the dot region unlike the multi-gap structure, the liquid crystal alignment is not disturbed due to the step, so that a liquid crystal device with excellent reliability can be obtained. Further, since the reflective polarizing layer 39 for performing reflective display is provided on the TFT array substrate 10, it is not necessary to dispose the TFT array substrate 10 on the display surface side of the liquid crystal device. Therefore, irregular reflection of external light due to metal wiring or the like as in the case where the TFT array substrate 10 is arranged on the display surface side does not occur, and a liquid crystal device excellent in visibility can be obtained.

In this embodiment, the common electrode 29 that applies a voltage to the liquid crystal together with the pixel electrode 9 is provided on the reflective polarizing layer 39. In the reflective polarizing layer 39, as described with reference to FIG. 9, a resin layer or the like for flattening the surface of the prism array 81 is provided on the surface of the dielectric interference film 85. If a transparent conductive film made of ITO or the like is formed on the dielectric interference film 85, the transparent conductive film can function as the common electrode 29, which contributes to manufacturing efficiency and cost reduction. Become.
The common electrode 29 only needs to be provided at a position spaced apart from the pixel electrode 9 via at least one insulating film. For example, the common electrode 29 is provided between the gate insulating film 11 and the second interlayer insulating film 13. The wiring layer may be formed, or may be formed in the wiring layer between the first interlayer insulating film 12 and the gate insulating film 11.

(Third embodiment)
Next, a liquid crystal device according to a third embodiment of the present invention will be described with reference to FIGS.
FIG. 11 is a plan configuration diagram showing an arbitrary one-dot region in the liquid crystal device 300 of the present embodiment, and FIG. 12 is a cross-sectional configuration diagram taken along the line DD ′ of FIG.

  The liquid crystal device 300 of the present embodiment is a liquid crystal device having a configuration using a top gate type polysilicon TFT 130 instead of the amorphous silicon TFT 30 of the liquid crystal device 100 of the first embodiment, and has a configuration other than the configuration related to the pixel switching element. The basic configuration is the same as that of the liquid crystal device 100 of the first embodiment. FIG. 11 is a diagram corresponding to FIG. 2A in the first embodiment, and FIG. 12 is a diagram corresponding to FIG. Therefore, in each drawing referred to in the present embodiment, the same reference numerals are given to the same constituent elements as those of the liquid crystal device 100 of the first embodiment shown in FIGS. 1 to 5. Description is omitted.

As shown in FIG. 11, a pixel electrode (second electrode) 9, a common electrode (first electrode) 19, and a pixel electrode 9 via a capacitance electrode 131 are arranged in the dot region of the liquid crystal device 300 of the present embodiment. An electrically connected TFT 130 is provided.
The polysilicon semiconductor layer 135 constituting the TFT 130 is formed in a rectangular shape in plan view that is long in the X-axis direction, and a drain electrode extending from the capacitor electrode 131 at the −X side end of the semiconductor layer 135. 132 is electrically connected through a drain contact hole. On the other hand, the source electrode 6b branched from the data line 6a extending in the Y-axis direction is electrically connected to the + X side end of the semiconductor layer 135 through a source contact hole.

  A scanning line 3a extending in the X-axis direction is provided in the vicinity of the semiconductor layer 135, and a gate electrode 133 formed by branching a part of the scanning line 3a crosses the semiconductor layer 135 in the Y-axis direction at the center. Arranged to do. A capacitance line 3b extending in the X-axis direction is provided between the semiconductor layer 135 and the pixel electrode 9, and the capacitance electrode 131 overlaps in a planar manner at a portion where the capacitance line 3b is partially widened to the + Y side. The storage capacitor 70 is formed at the position. On the capacitor electrode 131, the contact portion 9 b of the pixel electrode 9 is disposed so as to advance, and the pixel electrode 9 and the capacitor electrode 131 are electrically connected via the pixel contact hole 47 at the position.

  As in the first embodiment, the common electrode 19 includes a transparent common electrode 19t disposed on the + Y side of the dot region and a reflective common electrode 19r disposed on the −Y side. A region where the planar region overlaps with the planar region including the pixel electrode 9 is a transmissive display region T. In addition, a region where the planar region of the reflective common electrode 19r and the planar region including the pixel electrode 9 overlap is the reflective display region R.

  Referring to the cross-sectional structure shown in FIG. 12, the liquid crystal device 300 includes a TFT array substrate (first substrate) 10 and a counter substrate (second substrate) 20 that are opposed to each other with the liquid crystal layer 50 interposed therebetween. A backlight 90 is provided on the back side (the lower side in the figure) of the array substrate 10. Since the configuration of the counter substrate 20 is the same as that of the first embodiment, a detailed description thereof is omitted.

  A transparent common electrode 19t made of a transparent conductive material such as ITO and a reflective common electrode 19r mainly made of a reflective metal film such as aluminum are partitioned and formed on the substrate body 10A that forms the base of the TFT array substrate 10. A semiconductor layer 135 made of a polysilicon film is formed in the opening formed by partially removing the transparent common electrode 19t.

  A gate insulating film 11 is formed so as to cover the semiconductor layer 135 and the common electrode 19, and a scanning line 3 a, a gate electrode 133, and a capacitor line 3 b are formed on the gate insulating film 11. A first interlayer insulating film 12 is formed on the gate insulating film 11 so as to cover the scanning line 3a, the gate electrode 133, and the capacitor line 3b, and the source electrode 6b (data line 6a) is formed on the first interlayer insulating film 12. ), A drain electrode 132 and a capacitor electrode 131 are formed. A source contact hole 12s and a drain contact hole 12d that reach the semiconductor layer 135 through the first interlayer insulating film 12 and the gate insulating film 11 are provided, and the source electrode 6b and the semiconductor layer 135 are provided via the source contact hole 12s. And are electrically connected. The drain electrode 132 and the semiconductor layer 135 are electrically connected through the drain contact hole 12d.

  Here, in the polysilicon film constituting the semiconductor layer 135, impurities such as phosphorus and boron are introduced into a region excluding a region (channel region) that overlaps with the gate electrode 133 in a plane, and these impurity introduction regions are introduced. The source electrode 6b and the drain electrode 132 are electrically connected.

  A second interlayer insulating film 13 is formed so as to cover the source electrode 6 b, the drain electrode 132, and the capacitor electrode 131, and the pixel electrode 9 is formed on the second interlayer insulating film 13. A pixel contact hole 47 that penetrates through the second interlayer insulating film 13 and reaches the capacitor electrode 131 is formed, and the contact portion 9 b of the pixel electrode 9 and the capacitor electrode 31 are electrically connected via the pixel contact hole 47. Has been. An alignment film 18 is formed on the pixel electrode 9.

The arrangement of the optical axes in the liquid crystal device 300 of the present embodiment is the same as the arrangement of the optical axes in the liquid crystal device 100 of the first embodiment shown in FIG. That is, the rubbing direction of the alignment films 18 and 28 forms an angle of about 30 ° with respect to the extending direction (Y-axis direction) of the pixel electrode portion 9c, and the reflective common electrode 19r is formed with respect to this rubbing direction. The transmission axes of are parallel. The transmission axis of the polarizing plate 14 of the TFT array substrate 10 is arranged in a direction orthogonal to the rubbing direction, and the transmission axis of the polarizing plate 24 of the counter substrate 20 is parallel to the rubbing direction. It is arranged in the direction.
The liquid crystal device 300 having such an optical axis arrangement can perform the same operation as the operation of the liquid crystal device 100 according to the first embodiment described with reference to FIG. 5, and is bright in both reflective display and transmissive display. A high-contrast display can be obtained.

  In the liquid crystal device 300 according to the present embodiment having the above-described configuration, the polysilicon TFT 130 having high carrier mobility and capable of high-speed operation is used as the pixel switching element. Therefore, high-definition that requires high-speed switching operation of the pixel is required. It can be easily applied to a liquid crystal device. In this embodiment, since the top gate TFT 130 is used, the common electrode 19 can be provided in the same layer as the semiconductor layer 135 as shown in FIG. An FFS type liquid crystal device can be configured while using the same layer configuration as the TFT array substrate in the case where no TFT is provided. Therefore, since it can be manufactured without adding a new wiring layer, it is advantageous in terms of process ease and manufacturing cost.

  Further, similarly to the liquid crystal devices of the first and second embodiments, since the layer thickness of the liquid crystal layer 50 is constant in the dot area, the drive voltage does not become uneven in the dot area, and high quality is achieved. Can be obtained. Further, since it is not necessary to form a step in the dot region unlike the multi-gap structure, the liquid crystal alignment is not disturbed due to this step, and a liquid crystal device with excellent reliability can be obtained. Furthermore, since the reflective common electrode 19r for performing reflective display is provided on the TFT array substrate 10, it is not necessary to dispose the TFT array substrate 10 on the display surface side of the liquid crystal device. Therefore, irregular reflection of external light due to metal wiring or the like as in the case where the TFT array substrate 10 is arranged on the display surface side does not occur, and a liquid crystal device excellent in visibility can be obtained.

(Fourth embodiment)
Next, a liquid crystal device according to a fourth embodiment of the present invention will be described with reference to FIGS.
FIG. 13 is a circuit configuration diagram of a plurality of dot regions arranged in a matrix that constitutes the liquid crystal device 400 of the present embodiment. FIG. 14 is a plan configuration diagram showing an arbitrary one-dot region in the liquid crystal device 400 of the present embodiment, and FIG. 15 is a cross-sectional configuration diagram taken along the line FF ′ of FIG.

  The liquid crystal device 400 of the present embodiment is an active matrix type liquid crystal device using a TFD (Thin Film Diode) element as a pixel switching element. Further, similarly to the first to third embodiments, the FFS type electrode configuration is provided, and the basic configuration other than the configuration related to the pixel switching element is the same as that of the liquid crystal device of the first to third embodiments. In each drawing referred to in the present embodiment, the same components as those in the liquid crystal device 100 according to the first embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals. Omitted.

  As shown in FIG. 13, the liquid crystal device 400 has a plurality of dots 75 arranged in a matrix in plan view, and a plurality of first wirings 59 and a plurality of dots are defined so as to partition these dots 75. The second wiring 66 extends. The liquid crystal device 400 includes a first drive circuit 401 and a second drive circuit 402. The plurality of first lines 59 are electrically connected to the first drive circuit 401, and the plurality of second lines 66 are The second drive circuit 402 is electrically connected. With such a configuration, drive signals from the first drive circuit 401 and the second drive circuit 402 are supplied to each dot 75 via the first wiring 59 and the second wiring 66. In each dot 75, a TFD element 60 and a liquid crystal display element (liquid crystal capacitor) 50 are formed between the second wiring 66 and the first wiring 59.

  As shown in FIG. 14, a pixel electrode (second electrode) 9, a common electrode (first electrode) 59, and a TFD element 60 are provided in the dot region of the liquid crystal device 400. The common electrode (first wiring) 59 is a strip-shaped conductive film extending in the X-axis direction, and an element wiring (second wiring) 66 that intersects the common electrode 59 and extends in the Y-axis direction extends along the edge of the pixel electrode 9. It is arranged like that.

  The TFD element 60 includes a first electrode 63 having a rectangular shape that is long in the Y-axis direction, a wiring branch part 64 that branches from the element wiring 66 and extends to the −X side, and a base end part 9 a of the pixel electrode 9. It is mainly composed of an electrode wiring 65 extending in the X-axis direction. The TFD element 60 also includes a first element portion 61 formed at the intersection between the first electrode 63 and the wiring branch portion 64, and a second element portion formed at the intersection between the first electrode 63 and the electrode wiring 65. 62, a so-called back-to-back TFD element in which the first element part 61 and the second element part 62 are connected back to back (electrically in opposite directions).

  The end of the electrode wiring 65 opposite to the TFD element 60 is disposed so as to intersect with the contact portion 9 b of the pixel electrode 9 and is electrically connected to the pixel electrode 9. In this manner, the TFD element 60 is interposed between the element wiring 66 and the pixel electrode 9. A columnar spacer 40 is provided in the dot area.

  15, the liquid crystal device 400 has a configuration in which an element substrate (first substrate) 110 and a counter substrate (second substrate) 120 are arranged to face each other with the liquid crystal layer 50 interposed therebetween. I have. Since the configuration of the counter substrate 120 is the same as that of the counter substrate 20 according to the first embodiment, the description thereof is omitted.

  The element substrate 110 is provided with a substrate body 10A made of a light-transmitting substrate such as glass or quartz and a base, and a first electrode 63 made of tantalum or an alloy thereof and a common electrode 59 are formed on the substrate body 10A. Has been. The surface of the first electrode 63 is covered with an element insulating film 63a made of, for example, a tantalum oxide film. The common electrode 59 is formed by partitioning a transparent common electrode 59t made of a transparent conductive material such as ITO and a reflective common electrode 59r mainly composed of a light reflective metal film such as aluminum in a dot region. The reflective common electrode 59r is a reflective polarizing layer having a configuration equivalent to that of the reflective common electrode 19r according to the first embodiment.

  An interlayer insulating film 67 made of an inorganic insulating material such as silicon oxide or a resin material such as acrylic is formed on the substrate main body 10A and the common electrode 59, and an opening provided through the interlayer insulating film 67. The first electrode 63 is disposed in the portion 58. A wiring branch portion 64 (element wiring 66), an electrode wiring 65, and a pixel electrode 9 are formed on the interlayer insulating film 67. One end of each of the wiring branch portion 64 and the electrode wiring 65 extends from above the interlayer insulating film 67 into the opening 58 and contacts the element insulating film 63a. At the contact position, the first element portion 61 and the second element portion are contacted. 62 MIM (Metal-Insulator-Metal) structures are formed. An alignment film 18 is formed so as to cover the pixel electrode 9, the wiring branch portion 64, the electrode wiring 65, and the like.

The arrangement of the optical axes in the liquid crystal device 400 of the present embodiment is the same as the arrangement of the optical axes in the liquid crystal device 100 of the first embodiment shown in FIG. That is, the rubbing direction of the alignment films 18 and 28 forms an angle of about 30 ° with respect to the extending direction (Y-axis direction) of the pixel electrode portion 9c. The transmission axes of are parallel. Further, the transmission axis of the polarizing plate 14 of the element substrate 110 is arranged in a direction orthogonal to the rubbing direction, and the transmission axis of the polarizing plate 24 of the counter substrate 120 is parallel to the rubbing direction. Is arranged.
The liquid crystal device 400 having such an optical axis arrangement can perform the same operation as that of the liquid crystal device 100 according to the first embodiment described with reference to FIG. 5, and is bright in both the reflective display and the transmissive display. A high contrast display can be obtained.

  Since the liquid crystal device 400 having the above configuration includes the TFD element 66 as a pixel switching element, it can be manufactured by a simple process, which is advantageous in terms of manufacturing cost. In addition, since it is not necessary to provide a storage capacitor, the aperture ratio of the pixel is improved and a bright display can be obtained. Further, if the FFS method is employed as in the liquid crystal device 400 of the present embodiment, the pixel electrode 9 and the common electrode 59 are opposed to each other through the insulating film in the substrate thickness direction. Therefore, the voltage of the pixel electrode 9 is easily held, and the liquid crystal device can be suitably used for a high-definition liquid crystal device with a small liquid crystal capacity.

  Further, similarly to the liquid crystal devices of the first to third embodiments, since the layer thickness of the liquid crystal layer 50 is constant in the dot region, the drive voltage does not become uneven in the dot region, and high quality is achieved. Can be obtained. Further, since it is not necessary to form a step in the dot region unlike the multi-gap structure, the liquid crystal alignment is not disturbed due to this step, and a liquid crystal device with excellent reliability can be obtained. Further, since the reflective common electrode 59r for performing reflective display is provided on the element substrate 110, it is not necessary to dispose the element substrate 110 on the display surface side of the liquid crystal device. Therefore, irregular reflection of external light due to metal wiring or the like as in the case where the element substrate 110 is arranged on the display surface side does not occur, and a liquid crystal device with excellent visibility can be obtained.

(Electronics)
FIG. 16 is a perspective configuration diagram of a mobile phone which is an example of an electronic apparatus provided with the liquid crystal device according to the present invention in a display portion. The mobile phone 1300 uses the liquid crystal device of the present invention as a small-size display portion 1301. A plurality of operation buttons 1302, an earpiece 1303, and a mouthpiece 1304.
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 a reflective display can be obtained.

1 is a diagram illustrating a circuit configuration of a liquid crystal device according to a first embodiment. FIG. 3A is a plan configuration diagram of an arbitrary one-dot region (a) and an optical axis arrangement diagram (b). FIG. 3 is a cross-sectional configuration diagram taken along line A-A ′ of FIG. 2. FIG. 2A is a plan configuration diagram of a reflective polarizing layer, and FIG. FIG. 3 is an operation explanatory diagram of the liquid crystal device of the first embodiment. FIG. 9 is an operation explanatory diagram of a liquid crystal device shown as a comparative example. The figure which shows 1 dot area | region and optical axis arrangement | positioning of the liquid crystal device of 2nd Embodiment. FIG. 8 is a cross-sectional configuration diagram taken along line B-B ′ of FIG. 7. The perspective view (a) of a reflective polarizing layer, and a side view (b). Explanatory drawing of operation | movement of the liquid crystal device of 2nd Embodiment. FIG. 9 is a plan configuration diagram illustrating a one-dot region of a liquid crystal device according to a third embodiment. FIG. 11 is a sectional configuration view taken along line D-D ′ of FIG. 10. The circuit block diagram of the liquid crystal device of 4th Embodiment. The plane block diagram which shows the 1 dot area | region similarly. FIG. 14 is a cross-sectional configuration diagram taken along line F-F ′ in FIG. 13. The perspective block diagram which shows embodiment of an electronic device.

Explanation of symbols

  100, 200, 300, 400 Liquid crystal device, 10 TFT array substrate (first substrate), 20 Counter substrate (second substrate), 10A, 20A substrate body, 101 Data line drive circuit, 102 Scan line drive circuit, 30 TFT, 3a scanning line, 3b capacitance line, 6a data line, 6b source electrode, 9 pixel electrode (second electrode), 9a base end, 9b contact part, 9c pixel electrode part, 19, 29, 59 common electrode (first electrode) ), 19t transparent common electrode, 19r reflective common electrode, 39 reflective polarizing layer, 31, 131 capacitive electrode, 32, 132 drain electrode, 133 gate electrode, 59 element wiring, 60 TFD element, 61 first element part, 62 second Element part, 66 Common electrode (first electrode), 70 Storage capacitor, 71 Metal film, 72 Slit, 81 Prism array, 85 Dielectric Interference film, 90 backlight (illumination device), 110 element substrate (first substrate), 120 counter substrate (second substrate).

Claims (10)

A transflective liquid crystal device comprising a first substrate and a second substrate facing each other with a liquid crystal layer interposed therebetween, and performing reflective display and transmissive display in one dot region,
A first substrate formed in the dot region on the first substrate, an interlayer insulating film covering the first electrode, and a substrate substantially between the first electrode formed on the interlayer insulating film. A second electrode for generating an electric field in a plane direction and a reflective polarizing layer are provided,
The reflective polarizing layer has a transmission axis and a reflection axis intersecting the transmission axis, reflects light having a polarization component parallel to the reflection axis out of light incident on the reflective polarization layer, and transmits the light to the transmission axis. A liquid crystal device comprising a transflective reflective polarizing layer that transmits light of a parallel polarization component.   The liquid crystal device according to claim 1, wherein the reflective polarizing layer is partially formed in the dot region.   The liquid crystal device according to claim 1, wherein the reflective polarizing layer is formed on substantially the entire surface of the dot region.   4. The liquid crystal device according to claim 1, wherein the reflective polarizing layer includes a metal reflective film provided with a plurality of fine slit-shaped openings. 5.   The liquid crystal device according to claim 4, wherein the reflective polarizing layer is electrically connected to the first electrode.   4. The reflection polarizing layer includes a prism array in which a plurality of prisms are arranged, and a dielectric interference film formed on the prism array. The liquid crystal device described.   The liquid crystal device according to claim 1, wherein a thickness of the liquid crystal layer is substantially uniform in the dot region.   The liquid crystal device according to claim 1, wherein an illumination device is disposed on an outer surface side of the first substrate. A polarizing plate is provided between the first substrate and the lighting device,
9. The liquid crystal device according to claim 8, wherein a transmission axis of the polarizing plate is disposed in a direction substantially orthogonal to a transmission axis of the reflective polarizing layer.   An electronic apparatus comprising the liquid crystal device according to claim 1.

Images