JP2007052455A - Liquid crystal display device, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device with which a wide viewing field angle display is available both in a transmissive display and in a reflective display. <P>SOLUTION: The liquid crystal display device which is equipped with a transmissive display region and a reflective display region in a dot area, is equipped with a liquid crystal layer thickness adjusting layer to make the thickness of a liquid crystal layer in the reflective display region thinner than that in the transmissive display region. The liquid crystal layer contains liquid crystal molecules with negative dielectric anisotropy. In the transmissive display region and in the region with the liquid crystal layer thickness adjusting layer formed thereon, protrusions composed of a dielectric are formed on a substrate with a pixel electrode formed thereon or on a substrate with a counter electrode formed thereon, wherein the protrusions formed in the region with the liquid crystal layer thickness adjusting layer formed thereon are in contact with the substrate facing the substrate with the protrusions formed thereon, and are placed on the outside of the dot area, and concerning the inside of the dot area, the protrusions are formed only on the transmissive display region of the reflective display region and the transmissive display region. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device and an electronic apparatus, and more particularly to a technique for obtaining a display with a wider viewing angle in a liquid crystal display device using a vertical alignment type liquid crystal.

  As a liquid crystal display device, a transflective liquid crystal display device having both a reflection mode and a transmission mode is known. In such a transflective liquid crystal display device, a liquid crystal layer is sandwiched between an upper substrate and a lower substrate, and a reflective film in which a window for light transmission is formed on a metal film such as aluminum is disposed below. A substrate that is provided on the inner surface of the substrate and that functions as a transflective plate has been proposed. In this case, in the reflection mode, external light incident from the upper substrate side passes through the liquid crystal layer, is reflected by the reflective film on the inner surface of the lower substrate, passes through the liquid crystal layer again, and is emitted from the upper substrate side, contributing to display. To do. On the other hand, in the transmissive mode, light from the backlight incident from the lower substrate side passes through the liquid crystal layer from the window portion of the reflective film, and then is emitted to the outside from the upper substrate side, contributing to display. Accordingly, of the reflective film formation region, the region where the window is formed is the transmissive display region, and the other region is the reflective display region.

However, the conventional transflective liquid crystal device has a problem that the viewing angle in transmissive display is narrow. This is because a transflective plate is provided on the inner surface of the liquid crystal cell so that parallax does not occur, and there is a limitation that reflection display must be performed with only one polarizing plate provided on the viewer side. This is because the degree of freedom in design is small. In order to solve this problem, Jisaki et al. Proposed a new liquid crystal display device using vertically aligned liquid crystal in Non-Patent Document 1 below. The characteristics are the following three. (1) A “VA (Vertical Alignment) mode” is adopted in which a liquid crystal having a negative dielectric anisotropy is aligned perpendicularly to a substrate, and the liquid crystal is tilted by applying a voltage. (2) A “multi-gap structure” is employed in which the liquid crystal layer thickness (cell gap) is different between the transmissive display area and the reflective display area (refer to, for example, Patent Document 1).
(3) The transmissive display area is a regular octagon, and a projection is provided at the center of the transmissive display area on the counter substrate so that the liquid crystal tilts in eight directions within this area. In other words, “alignment division structure” is adopted.

Japanese Patent Laid-Open No. 11-242226 JP 2002-350853 A "Development of transflective LCD for high contrast and wide viewing angle by using homeotropic alignment", M. Jisaki et al., Asia Display / IDW'01, p.133-136 (2001)

  The provision of the multi-gap structure as in Patent Document 1 in the transflective liquid crystal display device makes it possible to align the electro-optical characteristics (transmittance-voltage characteristics, reflectivity-voltage characteristics) of the transmissive display area and the reflective display area. It is very effective. This is because light passes through the liquid crystal layer only once in the transmissive display region, but light passes through the liquid crystal layer twice in the reflective display region.

  However, when such a multi-gap structure is employed and the liquid crystal tilt direction is controlled using the protrusions as described above, for example, when a spacer for regulating the liquid crystal layer thickness is disposed, the spacer May float in the transmissive display region where the liquid crystal layer is thick, or it may be cumbersome because it is necessary to design while considering the height of the protrusion and the size of the spacer. In other words, in a liquid crystal display device in which a projection that regulates the direction in which the liquid crystal is tilted is added to the multi-gap structure, it takes time to design the liquid crystal layer thickness. If an error occurs in the design, it may be a cause of defects.

  The present invention has been made in order to solve the above-described problems, and in a transflective liquid crystal display device using a vertically aligned liquid crystal, enables a wide viewing angle display and a liquid crystal layer. It is an object of the present invention to provide a liquid crystal display device having a more preferable configuration for regulating the thickness (substrate distance, so-called cell gap). In addition, in a transflective liquid crystal display device using a vertical alignment type liquid crystal, the manufacturing efficiency is improved by simplifying the configuration, and a highly reliable liquid crystal display device with less occurrence of defects is provided. It is another object of the present invention to provide a highly reliable electronic device including the liquid crystal display device.

  In order to achieve the above object, a liquid crystal display device of the present invention comprises a pixel electrode sandwiched between a substrate on which a pixel electrode is formed and a substrate on which a counter electrode is formed. A liquid crystal display device having a dot area and having a transmissive display area and a reflective display area in the dot area, wherein the liquid crystal layer thickness of the reflective display area is smaller than the liquid crystal layer thickness of the transmissive display area A liquid crystal layer thickness adjusting layer, wherein the liquid crystal layer includes liquid crystal molecules having negative dielectric anisotropy, and the pixel electrode is disposed in the transmissive display region and the region where the liquid crystal layer thickness adjusting layer is formed. A protrusion made of a dielectric is formed on the formed substrate or the substrate on which the counter electrode is formed, and the protrusion formed in the region where the liquid crystal layer thickness adjusting layer is formed is formed with the protrusion. In contact with the opposite substrate And the projection is formed only in the transmissive display area of the reflective display area and the transmissive display area within the dot area. To do.

  The liquid crystal display device of the present invention includes a liquid crystal layer thickness adjusting layer for combining a liquid crystal in a vertical alignment mode with a transflective liquid crystal display device, and further making the retardation in the reflective display region and the retardation in the transmissive display region substantially equal. Added (ie, added a multi-gap structure) with a configuration for controlling the alignment direction of the liquid crystal molecules and a configuration for controlling the thickness of the liquid crystal layer used as a spacer. It is.

That is, in the liquid crystal display device in the vertical alignment mode, liquid crystal molecules standing perpendicular to the substrate surface in the initial alignment state are tilted by applying an electric field. If not, the direction in which the liquid crystal molecules are tilted cannot be controlled, resulting in disorder of alignment (disclination), resulting in display defects such as light leakage, and the display quality is degraded. Therefore, in adopting the vertical alignment mode, the control of the alignment direction of the liquid crystal molecules when an electric field is applied is an important factor.
Therefore, in the liquid crystal display device of the present invention, the convex portion is formed at least in the transmissive display region of the dot region, and the alignment direction of the liquid crystal molecules in the region is regulated. Due to such alignment regulation, the liquid crystal molecules exhibit a vertical alignment in the initial state and have a pretilt corresponding to the shape of the convex portion. As a result, it is possible to regulate or control the direction in which the liquid crystal molecules fall within the dot region, and it is difficult for alignment disturbance (disclination) to occur, and it is possible to avoid display defects such as light leakage, and afterimages and Display defects such as spotted unevenness can be suppressed, and a liquid crystal display device with a wide viewing angle can be provided. In the present invention, a convex portion is provided at least in the transmissive display area in the dot area. This is because the transmissive display has higher visibility than the reflective display. Needless to say, convex portions may be formed in both the display area and the transmissive display area.

  In the present invention, a convex portion is formed in the transmissive display region for the purpose of regulating the alignment of liquid crystal molecules, and a convex portion is also formed outside the dot region. As a result, it is possible to regulate the direction in which the liquid crystal molecules fall even outside the dot region. Therefore, for example, an alignment defect occurs outside the dot region, and the alignment defect also occurs in the liquid crystal molecules within the dot region. It is difficult for problems to occur. In addition, since the convex portion formed outside the dot region is formed in the region where the liquid crystal layer thickness adjusting layer is disposed, the convex portion outside the dot region is formed in the liquid crystal layer thickness (substrate interval (hereinafter referred to as the substrate interval (hereinafter referred to as the substrate spacing)). , Also referred to as a cell gap))) can be used as a means for regulating. That is, since the liquid crystal layer thickness is configured to be small in the region where the liquid crystal layer thickness adjustment layer is formed, the convex portion formed here is used as a liquid crystal layer thickness regulating means for maintaining the cell gap at a predetermined thickness. Is possible. As described above, the liquid crystal display device of the present invention has a configuration that suitably regulates the direction in which the liquid crystal molecules are tilted, and regulates the cell gap with respect to at least one means for regulating the tilt direction of the liquid crystal molecules. By combining the functions, it is not necessary to separately provide a spacer or the like as in the prior art, and for example, the problem that the spacer floats in a transmissive display region having a relatively thick liquid crystal layer does not occur. In the present invention, for example, the inner surface side of the substrate means the liquid crystal layer side of the substrate, and the protruding portion protrudes from the substrate surface, for example, a liquid crystal layer thickness adjusting layer is formed on the inner surface of the substrate. In this case, it means that the convex portion protrudes from the inner surface of the liquid crystal layer thickness adjusting layer.

  Another solution is a liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of substrates and a transmissive display area and a reflective display area are provided in one dot area. The liquid crystal layer is made of a liquid crystal having an initial alignment state of vertical alignment and negative dielectric anisotropy, and the reflection layer is interposed between at least one of the pair of substrates and the liquid crystal layer. A liquid crystal layer thickness adjusting layer is provided for making the liquid crystal layer thickness of the display area smaller than the liquid crystal layer thickness of the transmissive display area, and at least one of the pair of substrates has a transmissive area within the dot area. Each of the display area and the reflective display area is provided with a convex portion protruding from the inner surface of the substrate into the liquid crystal layer. Also in such a liquid crystal display device, the tilt direction of the liquid crystal molecules is suitably regulated by the convex portion as in the configuration described above, and the convex portion formed in the reflective display region having a small liquid crystal layer thickness regulates the cell gap. It becomes possible to use as a means to do.

  In the liquid crystal display device of the present invention, the protrusion height of the convex portion can be configured to be approximately the same as the liquid crystal layer thickness of the reflective display region. In the present invention, since the liquid crystal layer thickness of the reflective display region is relatively small due to the adoption of the multi-gap structure, the convex portion is configured at substantially the same height as the liquid crystal layer thickness of the reflective display region. By doing so, it can be suitably used as means for regulating the cell gap. The convex portion may have an inclined surface that is inclined at a predetermined angle with respect to a surface that sandwiches the liquid crystal layer of the substrate, and the inclined surface is provided with such an inclined surface. It is possible to regulate the tilt direction of the liquid crystal along the line.

  In the liquid crystal display device of the present invention, an electrode for driving the liquid crystal is provided on the liquid crystal layer side of the pair of substrates, and the convex portion is provided on the liquid crystal layer side of at least one of the electrodes. In this case, an alignment film for vertically aligning the liquid crystal is formed on the convex portion and on the inner surface side of the liquid crystal layer of the electrode. In addition, a circularly polarizing plate for allowing circularly polarized light to enter the liquid crystal layer may be provided on the side of the pair of substrates different from the liquid crystal layer. As the circularly polarizing plate, a combination of a polarizing layer and a retardation layer can be used.

  Furthermore, the liquid crystal display device of the present invention includes an upper substrate and a lower substrate as a pair of substrates, and a backlight for transmissive display is provided on the side opposite to the liquid crystal layer of the lower substrate, and the liquid crystal layer of the lower substrate A reflective layer selectively formed in the reflective display region can be provided on the side. In this case, light from the backlight incident from the lower substrate side can be used for transmissive display, and external light such as illumination and sunlight incident from the upper substrate side can be reflected by the reflective layer to be used for reflective display. become.

  In addition, the convex part formed in the transmissive display area and the convex part formed outside the dot area or the convex part formed in the reflective display area are formed by the same process for the purpose of improving the manufacturing efficiency. In this case, the respective convex portions are made of the same material, and the respective convex portions can be simply constituted at substantially the same height.

  Next, an electronic apparatus according to the present invention includes the liquid crystal display device. According to such an electronic device, it is possible to provide an electronic device including a display unit capable of both a transmission mode and a reflection mode and capable of providing a wide viewing angle display in each display mode. .

[First Embodiment]
Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, in each figure, in order to make each layer and each member the size which can be recognized on drawing, the scale is varied for every layer and each member.

The liquid crystal display device of the present embodiment shown below is an example of an active matrix liquid crystal display device using a thin film diode (hereinafter abbreviated as TFD) as a switching element, and particularly reflective display and transmission. This is a transflective liquid crystal display device that enables display.
FIG. 1 shows an equivalent circuit for the liquid crystal display device 100 of the present embodiment. The liquid crystal display device 100 includes a scanning signal driving circuit 110 and a data signal driving circuit 120. The liquid crystal display device 100 is provided with signal lines, that is, a plurality of scanning lines 13 and a plurality of data lines 9 intersecting the scanning lines 13. The scanning lines 13 are provided by a scanning signal driving circuit 110, and the data lines 9 are provided. It is driven by the data signal driving circuit 120. In each pixel region 150, the TFD element 40 and the liquid crystal display element 160 (liquid crystal layer) are connected in series between the scanning line 13 and the data line 9. In FIG. 1, the TFD element 40 is connected to the scanning line 13 side and the liquid crystal display element 160 is connected to the data line 9 side. On the contrary, the TFD element 40 is connected to the data line 9 side and the liquid crystal display element 160 is connected to the data line 9 side. The display element 160 may be provided on the scanning line 13 side.

  Next, the planar structure of the electrodes provided in the liquid crystal display device of the present embodiment will be described with reference to FIG. As shown in FIG. 2, in the liquid crystal display device of the present embodiment, pixel electrodes 31 having a rectangular shape in plan view connected to the scanning lines 13 via the TFD elements 40 are provided in a matrix, and the pixel electrodes The common electrode 9 is provided in a strip shape (stripe shape) so as to be opposed to 31 in the direction perpendicular to the paper surface. The common electrode 9 is formed of data lines and has a stripe shape that intersects the scanning lines 13. In the present embodiment, each region in which each pixel electrode 31 is formed is a single dot region, and the display can be performed for each dot region arranged in a matrix.

Here, the TFD element 40 is a switching element that connects the scanning line 13 and the pixel electrode 31, and the TFD element 40 is formed on the surface of the first conductive film having Ta as a main component and the first conductive film, The MIM structure includes an insulating film mainly composed of Ta ₂ O ₃ and a second conductive film formed on the surface of the insulating film and mainly composed of Cr. The first conductive film of the TFD element 40 is connected to the scanning line 13 and the second conductive film is connected to the pixel electrode 31.

  Next, the pixel configuration of the liquid crystal display device 100 of the present embodiment will be described with reference to FIG. 3A is a schematic diagram showing a pixel configuration of the liquid crystal display device 100, particularly a planar configuration of the pixel electrode 31, and FIG. 3B is a schematic diagram showing an AA ′ cross section of FIG. 3A. . As shown in FIG. 2, the liquid crystal display device 100 according to the present embodiment has a dot region provided with a pixel electrode 31 inside a region surrounded by the data lines 9, the scanning lines 13, and the like. In this dot area, as shown in FIG. 3A, one colored layer of the three primary colors is arranged corresponding to one dot area, and the three dot areas (D1, D2, D3) are arranged. Pixels including the colored layers 22B (blue), 22G (green), and 22R (red) are formed.

On the other hand, as shown in FIG. 3B, the liquid crystal display device 100 according to the present embodiment has an initial alignment between an upper substrate (element substrate) 25 and a lower substrate (counter substrate) 10 disposed opposite thereto. A liquid crystal layer 50 made of a liquid crystal material whose state is vertical alignment, that is, a liquid crystal material having negative dielectric anisotropy, is sandwiched.
In the lower substrate 10, a reflective film 20 made of a highly reflective metal film such as aluminum or silver is partially formed on the surface of a substrate body 10 </ b> A made of a translucent material such as quartz or glass via an insulating film 24. The structure is made. Here, the formation area of the reflective film 20 becomes the reflective display area R, and the non-formation area of the reflective film 20, that is, the opening 21 of the reflective film 20 becomes the transmissive display area T. As described above, the liquid crystal display device according to the present embodiment is a vertical alignment type liquid crystal display device including the vertical alignment type liquid crystal layer 50 and is a transflective liquid crystal display device capable of reflective display and transmissive display. is there.

  The insulating film 24 formed on the substrate body 10A has an uneven shape 24a on its surface, and the surface of the reflective film 20 has an uneven portion following the uneven shape 24a. Since the reflected light is scattered by such irregularities, reflection from the outside is prevented, and a wide viewing angle display can be obtained.

  Further, the color filter 22 formed over the reflective display region R and the transmissive display region T on the reflective film 20 located in the reflective display region R and the substrate main body 10A located in the transmissive display region T. (In FIG. 3B, a red colored layer 22R) is provided. Here, the periphery of the colored layer 22R is surrounded by a black matrix BM made of metal chromium or the like, and the boundaries of the dot regions D1, D2, and D3 are formed by the black matrix BM (see FIG. 3A).

  Further, an insulating film 26 is formed on the color filter 22 at a position corresponding to the reflective display region R. That is, the insulating film 26 is selectively formed so as to be positioned above the reflective film 20 via the color filter 22, and the thickness of the liquid crystal layer 50 is transmitted to the reflective display region R along with the formation of the insulating film 26. The display area T is different. The insulating film 26 is made of, for example, an organic film such as acrylic resin having a film thickness of about 0.5 to 2.5 μm, and its layer thickness continuously changes in the vicinity of the boundary between the reflective display region R and the transmissive display region T. It has an inclined surface to do. The thickness of the liquid crystal layer 50 where the insulating film 26 does not exist is about 1 to 5 μm, and the thickness of the liquid crystal layer 50 in the reflective display region R is about half the thickness of the liquid crystal layer 50 in the transmissive display region T.

  Thus, the insulating film 26 functions as a liquid crystal layer thickness adjusting layer (liquid crystal layer thickness control layer) that varies the thickness of the liquid crystal layer 50 between the reflective display region R and the transmissive display region T depending on its own film thickness. is there. In the case of the present embodiment, the edge of the flat surface on the upper side of the insulating film 26 and the edge of the reflective film 20 (reflective display area) are substantially coincident, and a part or all of the inclined area of the insulating film 26 It will be included in the transmissive display area T.

  A common electrode 9 made of indium tin oxide (hereinafter abbreviated as ITO) is formed on the surface of the lower substrate 10 including the surface of the insulating film 26, and polyimide or the like is formed on the common electrode 9. An alignment film 27 made of is formed. The alignment film 27 functions as a vertical alignment film that aligns liquid crystal molecules perpendicularly to the film surface, and is not subjected to alignment treatment such as rubbing. In FIG. 3, the common electrode 9 is formed in a stripe shape extending in the direction perpendicular to the plane of the paper, and is configured as a common electrode for each of the dot regions formed side by side in the direction perpendicular to the plane of the paper. Further, the common electrode 9 is formed with a slit 91 having a shape in which a part of the electrode is partially cut out. Furthermore, in the present embodiment, the reflective film 20 and the common electrode 9 are separately provided and laminated. However, in the reflective display region R, a reflective film made of a metal film can be used as a part of the common electrode. .

  Next, on the upper substrate 25 side, a matrix-like pixel electrode 31 made of a transparent conductive film such as ITO is formed on a substrate body 25A made of a translucent material such as glass or quartz (on the liquid crystal layer side of the substrate body 25A). And an alignment film 33 that is subjected to the same vertical alignment treatment as the lower substrate 10 made of polyimide or the like. A protrusion 28 that protrudes from the inner surface of the pixel electrode 31 to the inside of the liquid crystal layer 50 in the dot region is formed on the inner surface side of the upper substrate 25, and further, a protrusion 58 that protrudes from the inner surface of the substrate to the inside of the liquid crystal layer 50 outside the dot region. Is formed.

  Next, the phase difference plate 18 and the polarizing plate 19 are provided on the outer surface side of the lower substrate 10 (the side different from the surface sandwiching the liquid crystal layer 50), and the phase difference plate 16 and the polarizing plate 17 are also provided on the outer surface side of the upper substrate 25. Are formed so that circularly polarized light can be incident on the inner surface of the substrate (the liquid crystal layer 50 side). The retardation plate 18 and the polarizing plate 19, the retardation plate 16 and the polarizing plate 17 are respectively circularly polarized light. It constitutes a board. The polarizing plate 17 (19) is configured to transmit only linearly polarized light having a polarization axis in a predetermined direction, and a λ / 4 retardation plate is employed as the retardation plate 16 (18). A backlight 15 serving as a light source for transmissive display is provided outside the polarizing plate 19 formed on the lower substrate 10.

  Here, in the liquid crystal display device 100 of the present embodiment, in order to regulate the alignment of the liquid crystal molecules in the liquid crystal layer 50, that is, for the liquid crystal molecules that are vertically aligned in the initial state, the tilt when applying a voltage between the electrodes As a means for regulating the direction, a protrusion made of a dielectric is formed on the inner surface side (liquid crystal layer side) of the electrode. In the example of FIG. 3, the projection 28 is formed in the transmissive display region T and on the inner surface side (liquid crystal layer side) of the pixel electrode 31 formed on the upper substrate 25 side.

  The protrusions 28 are formed in a line shape (stripe shape) in plan view so as to protrude from the inner surface (electrode main surface) of the substrate into the liquid crystal layer 50. Specifically, the protrusion 28 has a height of 0.5 to 2 for example. The thickness of the liquid crystal layer in the region where the insulating film 26 is not formed (that is, the reflective display region R) is approximately the same. Further, the protrusion 28 includes at least an inclined surface (including a gently curved shape) inclined at a predetermined angle with respect to the inner surface of the substrate (electrode main surface), and the tilt direction of the liquid crystal molecules LC along the inclined surface. It is supposed to regulate.

  Further, projections 58 are also formed outside the dot region, and the projections 58 are configured at substantially the same height as the projections 28 (in the drawing, the heights are different for facilitating visual recognition of each component member). And a conical or polygonal pyramid with an inclined surface. In this case, the protrusion 58 restricts the tilting direction of the liquid crystal molecules LC, and is disposed particularly in the region where the insulating film 26 is formed (reflection display region R). It also functions as a means.

  On the other hand, the common electrode 9 formed on the inner surface side of the lower substrate 10 is formed with a slit 91 having a shape in which a part of the electrode is partially cut out. By providing the slit 91, an oblique electric field is generated between the electrodes 9 and 31 in the slit forming region, and the tilt direction based on voltage application of liquid crystal molecules vertically aligned in the initial state is regulated according to the oblique electric field. Will be. As shown in FIG. 3A, the line-shaped slits 91 formed in the common electrode 9 have an alternate positional relationship when viewed in plan with the protrusions 28 formed in the pixel electrode 31. As a result, the tilt direction of the liquid crystal molecules LC can be regulated alternately between the slits 91 and the projections 28.

According to the liquid crystal display device 100 configured as described above, the following effects can be exhibited.
First, in the liquid crystal display device 100 of the present embodiment, the insulating film 26 is provided in the reflective display region R so that the thickness of the liquid crystal layer 50 in the reflective display region R is approximately half the thickness of the liquid crystal layer 50 in the transmissive display region T. Since it can be made smaller, the retardation contributing to the reflective display and the retardation contributing to the transmissive display can be made substantially equal, thereby improving the contrast.

  In general, when a voltage is applied to liquid crystal molecules having negative dielectric anisotropy aligned on a vertical alignment film that is not subjected to rubbing treatment, there is no restriction on the direction in which the liquid crystal tilts, so that the liquid crystal molecules fall in a disorderly direction. An orientation failure occurs. However, in the present embodiment, the protrusion 28 is formed on the inner surface side of the pixel electrode 31, and the common electrode 9 is positioned between adjacent protrusions 28 among the protrusions 28 formed on the pixel electrode 31. Since the slit 91 is formed, alignment regulation by the inclined surface of the projection 28 and / or alignment regulation by an oblique electric field based on the slit 91 occurs, and the direction in which the liquid crystal molecules vertically aligned in the initial state are tilted by voltage application is regulated. It becomes. As a result, the occurrence of disclination due to poor liquid crystal alignment is suppressed, so a high-quality display that hardly causes afterimages associated with the occurrence of disclination and rough spot-like unevenness when observed from an oblique direction. Can be obtained.

  In the present embodiment, the protrusions 28 are selectively disposed in the transmissive display region T. In order to suppress the occurrence of disclination by restricting the tilt direction of the liquid crystal molecules and to improve the display characteristics, the protrusions 28 are formed not only in the transmissive display area T but also in the reflective display area R. Although it is preferable, in the transmissive mode display and the reflective mode display, since the transmissive mode has higher visibility, it is preferable to form protrusions at least in the transmissive display region T. Of course, the above-described effect can be sufficiently exhibited even in a configuration in which protrusions are formed in the reflective display region R.

  Further, the projections 28 are formed in the transmissive display region T for the purpose of regulating the alignment of liquid crystal molecules, and the projections 58 are also formed outside the dot region. This makes it possible to regulate the direction in which the liquid crystal molecules fall even in the vicinity of the protrusion 58. Therefore, for example, an alignment failure occurs outside the dot region, which causes an alignment failure in the liquid crystal molecules at the periphery of the dot region. It is difficult for problems to occur. Furthermore, since the projection 58 formed outside the dot region is formed in the region where the insulating film 26 is disposed (reflection display region), the projection 58 is used as a means for regulating the cell gap. Is possible. That is, since the liquid crystal layer thickness is small in the region where the insulating film 26 is formed, the protrusion 58 formed in the region is used as a liquid crystal layer thickness regulating means for maintaining the cell gap at a predetermined thickness. It becomes possible.

  Therefore, the liquid crystal display device 100 of the present embodiment has a configuration that suitably regulates the direction in which the liquid crystal molecules are tilted, and regulates the cell gap with respect to at least one means for regulating the tilt direction of the liquid crystal molecules. By combining the functions, it is possible to provide a display with high contrast and high visibility with a simple configuration without separately providing a spacer or the like as in the prior art.

[Second Embodiment]
Next, a liquid crystal display device according to a second embodiment will be described with reference to the drawings. FIG. 4 is a schematic diagram showing a planar structure (a) and a cross-sectional structure (b) of the liquid crystal display device 200 of the second embodiment, and corresponds to FIG. 3 of the first embodiment. It is. The liquid crystal display device 200 of the second embodiment is substantially the same in basic structure as the liquid crystal display device 100 shown in FIG. 3 except that the configuration of protrusions and slits is mainly different. For those having the same reference numerals, the description will be omitted as the same constituent members unless otherwise specified.

  Unlike the liquid crystal display device 100 of the first embodiment, the liquid crystal display device 200 of the second embodiment has projections 28 located on the common electrode 9 of the lower substrate 10 and positioned in the transmissive display region T. On the other hand, a protrusion 58 is formed on the common electrode 9 of the lower substrate 10 at a position corresponding to the outside of the dot region. Unlike the first embodiment, the protrusion 28 is formed in a conical shape or a polygonal pyramid shape, and the protrusion 58 is disposed in a region where the insulating film 26 is formed as in the first embodiment. ing. On the other hand, a slit 32 is formed in the pixel electrode 31 of the upper substrate 25. In this case, the slit 32 is configured to surround the protrusion 28 in a plane.

  The liquid crystal display device 200 according to the second embodiment as described above exhibits the same effects as those of the first embodiment. That is, the protrusions 28 formed in the transmissive display region T function as means for regulating the direction in which the liquid crystal molecules fall, while the protrusions 58 formed on the insulating film 26 outside the dot region are in the direction in which the liquid crystal molecules fall. And function as means for regulating the cell gap. Therefore, since the liquid crystal display device 200 includes the protrusions 28 and the electrode slits 32 as a configuration that suitably regulates the direction in which the liquid crystal molecules are tilted, the occurrence of disclination due to liquid crystal alignment failure is suppressed, and the disclination It is possible to obtain a high-quality display in which afterimages associated with the occurrence and rough spot-like unevenness when observed from an oblique direction are unlikely to occur. Further, among the means for regulating the tilting direction of the liquid crystal molecules, the protrusion 58 formed on the insulating film 26 has a function of regulating the cell gap, so that a spacer or the like is not provided separately. With a simple configuration, it is possible to provide a display with high contrast and high visibility.

[Third Embodiment]
Next, a liquid crystal display device according to a third embodiment will be described with reference to the drawings. FIG. 5 is a schematic diagram showing a planar structure (a) and a cross-sectional structure (b) of the liquid crystal display device 300 of the third embodiment, and corresponds to FIG. 4 of the second embodiment. It is. The liquid crystal display device 300 of the third embodiment is substantially the same in basic structure as the liquid crystal display device 200 shown in FIG. 4 except that the formation positions of the protrusions are different from those of the second embodiment. Accordingly, those having the same reference numerals as those in FIG. 4 are omitted as the same constituent members unless otherwise specified.

  Similarly to the liquid crystal display device 200 of the second embodiment, the liquid crystal display device 300 of the third embodiment has projections 28 located on the common electrode 9 of the lower substrate 10 and positioned in the transmissive display region T. On the other hand, unlike the liquid crystal display device 200, no protrusion is formed outside the dot region. However, the reflective display region R in the dot region has a projection 29, and the projection 29 has a function of regulating the cell gap. The protrusion 29 is configured in a conical shape or a polygonal pyramid shape like the protrusion 28. On the other hand, a slit 32 is formed in the pixel electrode 31 of the upper substrate 25. In this case, the slit 32 is configured to surround the protrusions 28 and 29 in a plane.

  Such a liquid crystal display device 300 according to the third embodiment exhibits the same effects as those of the first and second embodiments. That is, the protrusions 28 formed in the transmissive display region T and the protrusions 29 formed in the reflective display region R function as means for regulating the direction in which the liquid crystal molecules are tilted. The protrusions 29 formed on the surface 26 regulate the direction in which the liquid crystal molecules fall and function as means for regulating the cell gap. Therefore, since the liquid crystal display device 300 includes the protrusions 28 and 29 and the electrode slit 32 as a configuration that suitably regulates the direction in which the liquid crystal molecules fall, the occurrence of disclination due to liquid crystal alignment failure is suppressed, and the disclination is suppressed. It is possible to obtain a high-quality display in which afterimages associated with the occurrence of the occurrence of a nation and a rough spot-like unevenness when observed from an oblique direction are unlikely to occur. Of the means for regulating the tilt direction of the liquid crystal molecules, the protrusion 29 formed on the insulating film 26 in the reflective display region R has a function of regulating the cell gap, thereby providing a spacer. It is possible to provide a high-contrast and high-visibility display with a simple configuration without separately arranging the above.

  Note that the protrusions 29 formed in the reflective display region R are configured so as to be in contact with the opposing substrate in order to restrict the cell gap. Therefore, the alignment regulating force of the liquid crystal molecules is higher than that of the protrusions 28. It will be weakened. Therefore, as shown in the liquid crystal display device 400 of FIG. 6, the stripe-shaped projections 29a are formed in the reflective display region R in order to regulate the cell gap. Can be increased. That is, in this case, since the inclined surface becomes larger than that of the conical shape or the like, it is possible to increase the orientation regulating force.

[Fourth Embodiment]
Next, a liquid crystal display device according to a fourth embodiment will be described with reference to the drawings. FIG. 7 is a schematic diagram showing a planar structure (a) and a cross-sectional structure (b) of the liquid crystal display device 500 of the fourth embodiment, and corresponds to FIG. 3 of the first embodiment. It is. The liquid crystal display device 500 according to the fourth embodiment is different from the liquid crystal display device 100 shown in FIG. 3 in the basic structure except that the positions and structures of protrusions and slits are different from those of the first embodiment. Are substantially the same, and therefore, those having the same reference numerals as those in FIG. 3 will not be described as the same constituent members unless otherwise specified.

  Similar to the liquid crystal display device 100 of the first embodiment, the liquid crystal display device 500 of the fourth embodiment has projections 28 located on the pixel electrodes 31 of the upper substrate 25 and positioned in the transmissive display region T. On the other hand, a protrusion 58 is formed at a position where the insulating film 26 is formed outside the dot region of the upper substrate 25, and the protrusion 58 functions to regulate the cell gap as in the first embodiment. It has. Unlike the first embodiment, the protrusion 28 is configured in a conical shape or a polygonal pyramid shape. On the other hand, a slit 91 is formed in the common electrode 9 of the lower substrate 10, and the slit 91 in this case is configured to surround the conical or polygonal pyramid-shaped protrusion 28 in a planar manner.

  The liquid crystal display device 500 according to the fourth embodiment as described above exhibits the same effects as those of the first to third embodiments. That is, the protrusions 28 formed in the transmissive display region T function as a means for regulating the direction in which the liquid crystal molecules fall, while the protrusions 58 disposed outside the dot region and at the position where the insulating film 26 is formed are formed of the liquid crystal molecules. It is supposed to function as a means to regulate the cell gap as well as to regulate the falling direction. Therefore, since the liquid crystal display device 500 includes the protrusions 28 and the electrode slits 32 as a configuration that favorably regulates the direction in which the liquid crystal molecules are tilted, the occurrence of disclination due to poor liquid crystal alignment is suppressed, and It is possible to obtain a high-quality display in which afterimages associated with the occurrence and rough spot-like unevenness when observed from an oblique direction are unlikely to occur. In addition, among the means for regulating the tilt direction of the liquid crystal molecules, the projection 58 disposed outside the dot region and corresponding to the position where the insulating film 26 is formed has a function of regulating the cell gap. Accordingly, it is possible to provide a display with high contrast and high visibility with a simple configuration without separately providing a spacer or the like.

[Fifth Embodiment]
Next, a liquid crystal display device according to a fifth embodiment will be described with reference to the drawings. FIG. 8 is a schematic diagram showing a planar structure (a) and a cross-sectional structure (b) of the liquid crystal display device 600 of the fifth embodiment, and is a drawing corresponding to FIG. 7 of the fourth embodiment. It is. The liquid crystal display device 600 of the fifth embodiment is substantially the same in basic structure as the liquid crystal display device 500 shown in FIG. 7 except that the formation positions of the protrusions are different from those of the fourth embodiment. Accordingly, those having the same reference numerals as those in FIG. 7 are omitted as the same constituent members unless otherwise specified.

  Similarly to the liquid crystal display device 500 of the fourth embodiment, the liquid crystal display device 600 of the fifth embodiment has projections 28 located on the pixel electrode 31 of the upper substrate 25 and in the transmissive display region T. On the other hand, unlike the liquid crystal display device 500, no protrusion is formed outside the dot region. However, the reflective display region R in the dot region has a projection 29, and the projection 29 has a function of regulating the cell gap. The protrusion 29 is configured in a conical shape or a polygonal pyramid shape like the protrusion 28. On the other hand, a slit 91 is formed in the common electrode 9 of the lower substrate 10, and the slit 91 in this case is configured to surround the protrusions 28 and 29 in a plane.

  Such a liquid crystal display device 600 according to the fifth embodiment exhibits the same effects as those of the first to fourth embodiments. That is, the protrusions 28 formed in the transmissive display region T and the protrusions 29 formed in the reflective display region R function as means for regulating the direction in which the liquid crystal molecules are tilted. The protrusions 29 arranged corresponding to the positions where the liquid crystal molecules 26 are formed function as means for regulating the cell gap as well as regulating the direction in which the liquid crystal molecules fall. Therefore, since the liquid crystal display device 600 includes the protrusions 28 and 29 and the electrode slit 91 as a configuration that favorably regulates the direction in which the liquid crystal molecules fall, the occurrence of disclination due to liquid crystal alignment failure is suppressed, and the disclination is suppressed. It is possible to obtain a high-quality display in which afterimages associated with the occurrence of a nation or a rough spot-like unevenness when observed from an oblique direction are unlikely to occur. Of the means for regulating the tilting direction of the liquid crystal molecules, the cell gap is also regulated for the protrusions 29 arranged in the reflective display region R and corresponding to the positions where the insulating film 26 is formed. As a result, it is possible to provide a display with high contrast and high visibility with a simple configuration without separately providing a spacer or the like.

  Note that the protrusions 29 formed in the reflective display region R are configured so as to be in contact with the opposing substrate in order to restrict the cell gap, and therefore the alignment regulating force of the liquid crystal molecules is the protrusion of the transmissive display region T. It becomes weaker than 28. Therefore, by forming the stripe-shaped protrusions 29a in the reflective display region R instead of the conical shape or the polygonal pyramid shape, the liquid crystal alignment regulating force can be increased as compared with the conical shape or the like. That is, in this case, since the inclined surface becomes larger than that of the conical shape or the like, it is possible to increase the orientation regulating force.

[Electronics]
Next, specific examples of the electronic apparatus including the liquid crystal display device according to the above embodiment of the present invention will be described.
FIG. 9 is a perspective view showing an example of a mobile phone. In FIG. 9, reference numeral 1000 denotes a mobile phone body, and reference numeral 1001 denotes a display unit using the liquid crystal display device. Since such an electronic apparatus includes the display unit using the liquid crystal display device of the above-described embodiment, the electronic apparatus includes a liquid crystal display unit that is bright, has high contrast, and has a wide viewing angle regardless of the use environment. Can be realized.

  As mentioned above, although the example was demonstrated about embodiment of this invention, the technical scope of this invention is not limited to these, A various change can be added in the range which does not deviate from the meaning of this invention. is there. For example, in the above-described embodiment, the retardation plate is configured as a single plate, but instead, it may be configured as a laminated body of a ½ wavelength plate and a ¼ wavelength plate. This laminated body functions as a broadband circularly polarizing plate, and the black display can be made more achromatic. Further, the shape of the protrusions and the shape of the electrode slits formed in this embodiment are not limited to the configuration in the above embodiment, and at least have a configuration for regulating the tilt direction of vertically aligned liquid crystal molecules. If you do. In each of the above embodiments, the example in which the insulating film 26 is formed on the lower substrate 10 side is shown. However, the insulating film 26 may be formed on the upper substrate 25 side. Although a TFD is used as a thin film transistor, a thin film transistor (TFT) can be used instead of the TFD.

FIG. 3 is an equivalent circuit diagram of the liquid crystal display device of the first embodiment. FIG. 2 is an explanatory view illustrating the electrode configuration of the liquid crystal display device of FIG. 1 in a plan view. The plane schematic diagram and cross-sectional schematic diagram which expand and show the principal part about the liquid crystal display device of FIG. The plane schematic diagram and cross-sectional schematic diagram which expand and show the principal part about the liquid crystal display device of 2nd Embodiment. The plane schematic diagram and cross-sectional schematic diagram which expand and show a principal part about the liquid crystal display device of 3rd Embodiment. The plane schematic diagram and cross-sectional schematic diagram which expand and show the principal part about the modification of the liquid crystal display device of 3rd Embodiment. The plane schematic diagram and cross-sectional schematic diagram which expand and show a principal part about the liquid crystal display device of 4th Embodiment. The plane schematic diagram and cross-sectional schematic diagram which expand and show the principal part about the liquid crystal display device of 5th Embodiment. FIG. 14 is a perspective view illustrating an example of an electronic device of the invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 9 ... Common electrode, 20 ... Reflective film, 26 ... Insulating film (liquid crystal layer thickness adjustment layer), 28, 29, 58 ... Projection, 31 ... Pixel electrode, 50 ... Liquid crystal layer, R ... Reflection display area, T ... Transmission display region.

Claims (4)

A liquid crystal layer is sandwiched between a substrate on which a pixel electrode is formed and a substrate on which a counter electrode is formed, and has a dot region including the pixel electrode, and a transmissive display region and a reflective display region in the dot region A liquid crystal display device comprising:
A liquid crystal layer thickness adjusting layer that makes the liquid crystal layer thickness of the reflective display region smaller than the liquid crystal layer thickness of the transmissive display region,
The liquid crystal layer includes liquid crystal molecules having negative dielectric anisotropy,
In the region where the transmissive display region and the liquid crystal layer thickness adjustment layer are formed, a protrusion made of a dielectric is formed on the substrate on which the pixel electrode is formed or the substrate on which the counter electrode is formed.
The protrusion formed in the region where the liquid crystal layer thickness adjusting layer is formed is in contact with the substrate opposite to the substrate where the protrusion is formed, and is disposed outside the dot region.
In the dot area, the projection is formed only in the transmissive display area among the reflective display area and the transmissive display area.   2. The protrusion is provided as an alignment regulating means for regulating the alignment of the liquid crystal, and has an inclined surface inclined at a predetermined angle with respect to a surface of the substrate that sandwiches the liquid crystal layer. A liquid crystal display device according to 1.   The liquid crystal display device according to claim 1, wherein the protrusion is formed on the substrate on which the counter electrode is formed.   An electronic apparatus comprising the liquid crystal display device according to claim 1.

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