JP4419502B2 - Liquid crystal display device and electronic device - Google Patents

Description

  The present invention relates to a liquid crystal display device and an electronic apparatus, and more particularly to a technique capable of obtaining a display with a high contrast and a wide 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 adopted in which the liquid crystal layer thickness (cell gap) is different between the transmissive display area and the reflective display area.
(3) The transmissive display area is a regular octagon, and a protrusion is provided at the center of the transmissive display area on the counter substrate so that the liquid crystal is tilted in all directions in this area. In other words, “alignment division structure” is adopted.

On the other hand, as a means for regulating the alignment of liquid crystal molecules when such vertically aligned liquid crystal is used, for example, Patent Document 1 discloses a method of forming a slit on an electrode in addition to the above-described protrusion, or a resin layer. A method for forming a recess in the resin layer is disclosed.
Japanese Patent Laid-Open No. 11-242225 "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)

  In the said nonpatent literature 1, the direction in which a liquid crystal molecule falls in the transmissive display area is controlled using the protrusion provided in the center. In order to configure in this way, one extra manufacturing process is required, resulting in high costs. However, if the direction in which the liquid crystal molecules are tilted is not controlled and tilted in a disordered direction, a discontinuous line called disclination appears at the boundary between different liquid crystal alignment regions, which may cause afterimages. In addition, since each alignment region of the liquid crystal has different viewing angle characteristics, there also arises a problem that when the liquid crystal device is viewed from an oblique direction, the liquid crystal device appears as rough spots.

  Also in Patent Document 1, the direction in which the liquid crystal molecules are tilted is controlled by using protrusions or by forming a resin layer on the inner surface of the substrate and forming a recess in this resin layer. Even in this case, in order to configure these protrusions or the resin layer, an extra manufacturing process is required once, which increases the cost.

  The present invention has been made to solve the above-described problems, and provides a configuration capable of easily controlling the direction in which liquid crystal molecules fall in a transflective liquid crystal display device in a vertical alignment mode. The purpose is to do. It is another object of the present invention to provide a liquid crystal display device capable of suppressing display defects such as afterimages and spotted unevenness and capable of displaying a wide viewing angle. In addition, a simple and suitable method for controlling the direction in which the liquid crystal is tilted is provided, particularly in a region where transmissive display is performed, and a liquid crystal display device having a uniform display and a wide viewing angle in both reflective display and transmissive display is provided. For the purpose. Furthermore, an object of the present invention is to provide an electronic device including such a liquid crystal display device.

  In order to achieve the above object, a liquid crystal display device according to the present invention includes a liquid crystal layer sandwiched between a pair of substrates, and a transmissive display region for performing transmissive display within one dot region and a reflective display for performing reflective display. The liquid crystal layer is made of a liquid crystal having negative dielectric anisotropy, and the reflective display region has a thickness of the liquid crystal layer of the reflective display region in the transmissive display region. A liquid crystal layer thickness adjusting layer for reducing the thickness of the liquid crystal layer is provided, the transmissive display region is provided with a convex portion protruding toward the liquid crystal layer side, and the liquid crystal layer thickness adjusting layer includes the liquid crystal layer. A concave portion in which a surface of the layer thickness adjusting layer is partially depressed is provided, and the liquid crystal layer thickness adjusting layer and the convex portion are formed of the same member.

  The liquid crystal display device of the present invention is a combination of a transflective liquid crystal display device and a vertical alignment mode liquid crystal, and has a preferable configuration for controlling the alignment direction when an electric field is applied to the vertical alignment mode liquid crystal. It has been found. When the vertical alignment mode is used, a negative type liquid crystal is generally used. However, since the liquid crystal molecules in the initial alignment state are standing perpendicular to the substrate surface by applying an electric field, no contrivance is required. Otherwise (unless pretilt is applied), the direction in which the liquid crystal molecules tilt cannot be controlled, and disorder of alignment (disclination) occurs, resulting in poor display such as light leakage, and deteriorates display characteristics. 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.

  Accordingly, in the liquid crystal display device of the present invention, in particular, in the transmissive display region, the convex shape is imparted to the sandwiching surface of the liquid crystal layer by the convex portion (the sandwiching surface convex shape imparting means), so that the liquid crystal molecules are vertically aligned in the initial state. And a pretilt corresponding to the convex shape. As a result, it is possible to regulate or control the direction in which the liquid crystal molecules are tilted, it is difficult to cause disorder of alignment (disclination), it is possible to avoid display defects such as light leakage, and afterimages, spot-like unevenness, etc. This makes it possible to provide a liquid crystal display device with a wide viewing angle.

  Further, by providing the liquid crystal layer thickness adjusting layer in the reflective display region, the retardation in the reflective display region and the retardation in the transmissive display region can be made substantially equal, thereby improving the contrast. Then, by forming a concave portion in which the surface of the liquid crystal layer thickness adjusting layer is partially depressed with respect to the liquid crystal layer thickness adjusting layer, the liquid crystal molecules exhibit vertical alignment in the initial state, It has a pretilt according to the concave shape. As a result, it is possible to regulate or control the direction in which the liquid crystal molecules are tilted, it is difficult to cause disorder of alignment (disclination), it is possible to avoid display defects such as light leakage, and afterimages, spot-like unevenness, etc. This makes it possible to provide a liquid crystal display device with a wide viewing angle.

  Furthermore, in the liquid crystal display device of the present invention, a liquid crystal layer thickness adjusting layer provided with a convex portion (clamping surface convex shape imparting means) as a means for imparting a convex shape to the liquid crystal layer sandwiching surface of the transmissive display region in the reflective display region. It is possible to manufacture the same shape as the liquid crystal layer thickness adjusting layer, and it is possible to easily give the convex shape. This leads to a reduction in manufacturing costs. That is, according to the present invention, the liquid crystal layer thickness adjustment layer is used to adjust the liquid crystal layer thickness in the reflective display region and the transmissive display region, and a reflective portion with a wide viewing angle is realized by forming a concave portion in the adjustment layer. By providing a convex shape to the liquid crystal layer sandwiching surface of the transmissive display region with the same member as the adjustment layer, it is possible to provide a liquid crystal display device that can realize transmissive display with a wide viewing angle. The liquid crystal layer thickness adjusting layer and the convex portion can be manufactured by the same process, for example, by forming the convex portion and the liquid crystal layer thickness adjusting layer by the same process. Even if it is constituted by one layer, the convex portion and the liquid crystal layer thickness adjusting layer can be manufactured by the same process.

  On the other hand, the liquid crystal display device of the present invention, as a different mode, has a liquid crystal layer sandwiched between a pair of substrates, a transmissive display region for performing transmissive display within one dot region, and a reflective display region for performing reflective display. The liquid crystal layer is made of a liquid crystal having a negative dielectric anisotropy, and the reflective display area and the transmissive display area are each an insulating layer configured in a predetermined pattern. In the reflective display area, the insulating layer is configured as a liquid crystal layer thickness adjusting layer for making the liquid crystal layer thickness of the reflective display area smaller than the liquid crystal layer thickness of the transmissive display area, The transmissive display region is configured as a convex portion protruding from the inner surface of the substrate to the liquid crystal layer, and the insulating layer formed in the reflective display region has a partially recessed surface. Concave part And wherein the are.

  Also in this case, as described above, the insulating layer is formed into a predetermined pattern by one manufacturing process, and the liquid crystal layer thickness adjusting layer and the convex portion (the sandwiching surface convex shape imparting unit) are formed in each of the reflective display region and the transmissive display region. ). That is, a solid insulating layer is formed on the entire inner surface of the substrate, the liquid crystal layer thickness adjusting layer is formed in a shape having a concave portion in the reflective display region, and a convex portion is formed in the transmissive display region. Then, it can be patterned into a predetermined shape by etching or the like.

  In the liquid crystal display device of the present invention described above, the convex portion can be formed at a position facing the concave portion on the substrate facing the substrate on which the liquid crystal layer thickness adjusting layer is formed. In this case, due to the synergistic effect of the concave portion formed in the liquid crystal layer thickness adjusting layer and the convex portion formed opposite thereto, it becomes possible to further increase the alignment regulation of liquid crystal molecules in the reflective display region, As a result, alignment disorder (disclination) is less likely to occur, display defects such as light leakage can be further avoided, display defects such as afterimages and spotted irregularities are suppressed, and liquid crystal with a wider viewing angle. A display device can be provided.

  Further, in the substrate on the side facing the substrate on which the liquid crystal layer thickness adjusting layer is formed, an electrode is formed at a position facing the concave portion, and the electrode is positioned at a position facing the concave portion, A configuration in which a slit in which the electrode is partially cut is formed may be employed. In this case, the synergistic effect of the concave portion formed in the liquid crystal layer thickness adjusting layer and the slit to the electrode formed opposite to the concave portion makes it possible to further increase the alignment regulation of the liquid crystal molecules in the reflective display region. Become. The reason for regulating the alignment of liquid crystal molecules by forming slits in such an electrode is that an oblique electric field is generated by forming a slit by cutting out a part of the electrode, and in the initial state according to the oblique electric field. This is based on the fact that the tilt direction of the aligned liquid crystal molecules during voltage application is regulated. Moreover, it is preferable to form a concave part rather than the convex part mentioned above as an orientation control means formed in the board | substrate on the side facing such a liquid-crystal layer thickness adjustment layer. This is because the liquid crystal layer thickness is reduced because the liquid crystal layer thickness adjusting layer is provided in the reflective display region, and a convex portion having a height capable of sufficient liquid crystal alignment regulation can be formed. This is because it may be difficult.

  In the present invention, the convex portion may have a configuration that regulates a direction in which the liquid crystal molecules are tilted based on an electric field change. Specifically, it is preferably configured as a conical or polygonal pyramidal projection, and the convex surface (inclined surface) is configured to be inclined by a predetermined angle with respect to the vertical alignment direction of the liquid crystal molecules. Is preferred. About the inclined surface of a convex-shaped part, it is preferable that the maximum inclination angle is 5 degrees-40 degrees. In this case, the inclination angle is an angle formed between the substrate and the inclined surface of the convex portion, and when the convex shape has a curved surface, it indicates an angle formed between the surface in contact with the curved surface and the substrate. Shall. In this case, if the maximum tilt angle is less than 5 °, it may be difficult to regulate the direction in which the liquid crystal molecules are tilted. If the maximum tilt angle exceeds 40 °, light leakage or the like may occur from that portion. Defects such as lowering may occur.

  In the present invention, the concave portion may have a configuration that regulates a direction in which the liquid crystal molecules are tilted based on an electric field change. Specifically, it is preferable that the liquid crystal layer thickness adjustment layer is configured as a concave shape that is recessed in a conical shape or a polygonal pyramid shape, and the concave inner surface (inclined surface) has a predetermined angle with respect to the vertical alignment direction of the liquid crystal molecules. It is preferable to constitute so as to incline only. The inclined surface formed on the inner surface of the concave portion preferably has a maximum inclination angle of 5 ° to 40 °. In this case, the inclination angle is an angle formed between the substrate and the inclined surface of the concave portion, and when the concave shape has a curved surface, it indicates an angle formed between the surface in contact with the curved surface and the substrate. And In this case, if the maximum tilt angle is less than 5 °, it may be difficult to regulate the direction in which the liquid crystal molecules are tilted. If the maximum tilt angle exceeds 40 °, light leakage or the like may occur from that portion. Defects such as lowering may occur.

  In each of the liquid crystal display devices described above, a backlight for transmissive display is provided on the opposite side of the one substrate of the pair of substrates to the liquid crystal layer, and on the liquid crystal layer side of the one substrate, A reflective film selectively formed in the reflective display region may be provided, and a concave / convex imparting layer for imparting a concave / convex shape to the reflective film may be formed in the reflective display region. In this case, the reflected light is effectively scattered by the uneven shape of the reflective film.

  The protruding portion formed in the transmissive display area preferably has a protruding height of about 0.5 μm to 2.5 μm. If the height of the protrusion is smaller than 0.5 μm, it may be difficult to regulate the direction in which the liquid crystal molecules fall, and if the height of the protrusion is larger than 2.5 μm, the light from the vicinity of the convex portion There is a possibility that display characteristics will be impaired due to large leakage. The height of the convex portion is preferably about 1.0 μm to 1.5 μm. In this case, it is possible to provide a better display.

  Further, an electrode having an opening on the convex portion may be formed on the inner surface side of the substrate on which the convex portion is formed. In this case, since there is no electrode on the convex portion, the direction in which the liquid crystal is tilted by the convex portion and the direction of the electric lines of force are inclined in opposite directions. It is possible to regulate the orientation of molecules.

  Next, an electronic apparatus according to the present invention includes the above-described liquid crystal display device. According to such an electronic apparatus, it is possible to provide an electronic apparatus including a display unit that can suppress display defects such as afterimages and spotted unevenness and that has a wide display angle and excellent display characteristics.

[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 into a size that can be recognized on the drawing, the scale is varied for each 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 (pixel structure) of the electrodes provided in the liquid crystal display device 100 of the present embodiment will be described with reference to FIG. As shown in FIG. 2, in the liquid crystal display device 100 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. The common electrode 9 is provided in a strip shape (stripe shape) so as to face the electrode 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 where each pixel electrode 31 is formed is one dot region, and a TFD element 40 is provided for each dot region arranged in a matrix, and display is performed for each dot region. It has a possible structure.

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 containing Ta ₂ O ₃ as a main component and a second conductive film formed on the surface of the insulating film and containing Cr as a main component. 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 illustrating 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 illustrating an AA ′ cross section of FIG. is there. 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 100 of 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 capable of reflective display and transmissive display. Device.

  The insulating film 24 formed on the substrate main body 10A has a concavo-convex shape 24a on its surface, and the surface of the reflective film 20 has concavo-convex following the concavo-convex 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. The insulating film 24 having such a concavo-convex shape 24a can be obtained, for example, by patterning a resin resist and applying another layer of resin thereon. The shape may be adjusted by applying heat treatment to the patterned resin resist.

  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 addition, a concave portion 29 is formed at the approximate center of the insulating film 26 in a plan view. The concave portion 29 is formed by recessing the insulating film 26 in an inverted conical shape. The concave portion 29 is configured such that the surface of the insulating film 26 is partially depressed, and functions as an inclined surface providing means for providing an inclined surface to the sandwiching surface of the liquid crystal layer 50. Is configured to have a valley-like inclined surface that is recessed from the surface of the insulating film 26 by a predetermined depth (for example, about 0.5 μm to 2.5 μm, preferably about 1.0 μm to 1.5 μm). For example, after the insulating film 26 is formed, the concave portion 29 can be obtained as a partial depression by partially removing a part of the surface of the insulating film 26 by etching or the like.

  On the other hand, a convex portion 28 made of the same member as the insulating film 26 is formed on the color filter 22 at a position corresponding to the transmissive display region T. That is, a resin-made convex portion 28 made of an organic film such as an acrylic resin, which is the same material, is formed in the transmissive display region T by the same manufacturing process as the insulating film 26 that is the liquid crystal layer thickness adjusting layer. . The convex portion 28 functions as a sandwiching surface convex shape imparting means for imparting a convex shape to the liquid crystal layer 50 from the inner surface of the lower substrate 10. Specifically, the convex portion 28 has a predetermined height from the color filter 22 to the liquid crystal layer 50. (For example, about 0.5 μm to 2.5 μm, preferably about 1.0 μm to 1.5 μm).

  Thus, in this embodiment, the insulating film 26 and the convex portion 28 are formed in the same layer, that is, an insulating layer (resin layer) having a predetermined pattern is formed in each of the reflective display region R and the transmissive display region T. In the reflective display region R, the insulating layer is configured as an insulating film 26 that is a liquid crystal layer thickness adjusting layer, while in the transmissive display region T, the inner surface of the substrate (the facing surfaces of a pair of substrates, the sandwiching surface of the liquid crystal layer). The liquid crystal layer 50 is configured as a convex portion 28 that imparts a convex shape. The convex portion 28 and the concave portion 29 are formed in the vicinity of the approximate centers of the transmissive display region T and the reflective display region R, respectively.

  Further, a striped common electrode 9 made of indium tin oxide (hereinafter abbreviated as ITO) is formed on the color filter 22 including the insulating film 26 and the convex portion 28. An alignment film 27 made of polyimide or the like is formed thereon. 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. In the present embodiment, the reflective film 20 and the common electrode 9 are formed separately, but 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.

  Further, 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. It is formed so that circularly polarized light can be incident on the inner surface side of the substrate (the liquid crystal layer 50 side). These retardation plate 18 and polarizing plate 19, retardation plate 16 and polarizing plate 17 are respectively circular polarizing plates. Is configured. 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). As such a circularly polarizing plate, it is possible to use a polarizing plate, a combination of a λ / 2 retardation plate and a λ / 4 retardation plate (broadband circularly polarizing plate), in this case, The black display can be made more achromatic. Further, it is possible to use a structure in which a polarizing plate, a λ / 2 retardation plate, a λ / 4 retardation plate, and a c plate (a retardation plate having an optical axis in the film thickness direction) are combined. Visualization can be achieved. 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, tilt when a voltage is applied between the electrodes. In order to regulate the direction, in the transmissive display region T, convex portions 28 are formed as protrusions made of a dielectric on the inner surface side (liquid crystal layer side) of the lower substrate 10. Specifically, in the example of FIG. 3, a protrusion that protrudes into the liquid crystal layer 50 inside the transmissive display region T and on the inner surface side (liquid crystal layer side) of the color filter 22 formed on the lower substrate 10. A shaped portion 28 is formed.

  Further, in the reflective display region R, a concave portion 29 is formed in the insulating film 26 as a liquid crystal layer thickness adjusting layer in order to regulate the tilt direction of the liquid crystal molecules. Specifically, in the example of FIG. 3, a concave portion 29 is formed in the reflective display region R, in which the surface of the insulating film 26 formed on the lower substrate 10 is partially depressed. .

  As shown in FIG. 4, the convex portion 28 formed as described above regulates the tilt direction of the liquid crystal molecules along the inclined surface, and the concave portion 29 is also inclined on the inner surface. The tilt direction of liquid crystal molecules is regulated along the plane. That is, the liquid crystal molecules in the vertical alignment in the initial state where no voltage is applied between the electrodes, when a voltage is applied, try to tilt in the direction intersecting with the electric field direction. The tilting direction of the liquid crystal molecules when a voltage is applied is regulated along the inclined surfaces of the convex portion 28 and the concave portion 29.

According to the liquid crystal display device 100 having the above-described configuration, the following preferable actions and effects can be exhibited.
First, in the liquid crystal display device 100 of the present embodiment, the insulating film 26 is selectively provided with respect to the reflective display region R, whereby the thickness of the liquid crystal layer 50 in the reflective display region R is set to the thickness of the liquid crystal layer 50 in the transmissive display region T. Since the thickness can be reduced to about half of the thickness, 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, as a means for regulating the direction in which the liquid crystal molecules are tilted, the convex portion 28 is formed on the common electrode 9 in the transmissive display region T, and the concave portion 29 is formed in the insulating film 26 in the reflective display region R. As a result, the alignment regulation by the inclined surface (mountain inclined surface) of the convex portion 28 and the alignment restriction by the inclined surface (valley inclined surface) of the concave portion 29 occur, and voltage application of the liquid crystal molecules vertically aligned in the initial state is applied. The direction of falling will be regulated by. As a result, since the occurrence of disclination due to liquid crystal alignment failure is suppressed, an afterimage associated with the occurrence of disclination and a rough spot shape when the display surface of the liquid crystal display device 100 is observed from an oblique direction. A high-quality display in which unevenness or the like hardly occurs can be obtained.

  And in the liquid crystal display device 100 of this Embodiment, the convex part 28 is formed in the transmissive display area | region T, and the concave part 29 is formed in the reflective display area | region R. In these convex part 28 and the concave part 29, As shown in FIG. 4, when viewed from the center (center axis) of the convex portion 28 and the concave portion 29, the directions in which the liquid crystal molecules fall are opposite to each other. That is, in the convex portion 28, the liquid crystal molecules tilt so as to go outward with the central axis of the convex portion 28 as the symmetry axis, while in the concave portion 29, the central axis of the concave portion 29 is used as the symmetry axis. The liquid crystal molecules tilt toward the inside. Therefore, the tilting direction of the liquid crystal molecules continuously changes in the transmissive display region T and the reflective display region R (see FIG. 4), and only the convex portion 28 and the concave portion 29, specifically, the upper substrate. It is possible to prevent or suppress the occurrence of disclination in the intermediate region between the convex portion 28 and the concave portion 29 without separately forming an orientation regulating means on the (element substrate) 25 side.

  That is, instead of forming the concave portion 29 by recessing the surface of the insulating film 26 in the reflective display region R, it is possible to form a convex portion on the insulating film 26. In this case, however, the transmissive display region T A discontinuous portion in the tilting direction of the liquid crystal molecules is formed between the convex portion 28 and the convex portion 28. However, the method of the present embodiment in which the concave portion 29 is formed in the insulating film 26 in the reflective display region R and the convex portion 28 is formed in the transmissive display region T to regulate the alignment of liquid crystal molecules is not such a problem. Since no continuous portion is formed between the two, it is possible to perform highly efficient alignment division of liquid crystal molecules.

  Further, in the present embodiment, the positions where the convex portions 28 and the concave portions 29 are formed are near the centers of the transmissive display region T and the reflective display region R, respectively. Since the region is fixed near the boundary between the transmissive display region T and the reflective display region R, uniform alignment division can be performed.

  Further, in the present embodiment, the convex portion 28 as the liquid crystal molecule alignment regulating means in the transmissive display region T is formed by the same process as the insulating film 26 as the liquid crystal layer thickness adjusting means in the reflective display region R. Therefore, it is possible to efficiently manufacture without increasing an extra manufacturing process, and it is possible to contribute to cost reduction.

  Note that the convex shape of the convex portion 28 and / or the concave shape of the concave portion 29 formed on the sandwiching surface of the liquid crystal layer 50 has a vertically symmetric shape in the longitudinal section. Specifically, since the convex portion 28 formed in the transmissive display region T is configured in a frustum shape, when the liquid crystal molecules are tilted, they are tilted in all directions, and a wide viewing angle is formed on both the top, bottom, left, and right sides of the display surface. Characteristics can be obtained. In order to obtain such a wide viewing angle characteristic, the convex portion is configured in a conical shape or an elliptical cone shape, or a polygonal pyramid shape, a truncated cone shape, an elliptical truncated cone shape, a truncated pyramid shape, or a hemispherical shape. It is preferable. The same applies to the concave portion 29, and it is preferable that the concave portion 29 has a conical, elliptical, or polygonal concavity.

[Second Embodiment]
The second embodiment of the present invention will be described below with reference to the drawings.
FIG. 5 is a schematic view corresponding to FIG. 3 of the first embodiment, showing a plan view and a sectional view of the liquid crystal display device 200 of the second embodiment. The basic configuration of the liquid crystal display device of the present embodiment is the same as that of the first embodiment, except that an insulating film 26 formed in the reflective display region R is formed on the upper substrate 25 side. Therefore, in FIG. 5, the same code | symbol is attached | subjected to the same component as FIG. 3, and detailed description is abbreviate | omitted.

  As shown in FIG. 5, in the liquid crystal display device 200 of the second embodiment, the color filter 22 (22R) is formed on the substrate body 25A (the liquid crystal layer 50 side, that is, the inner surface side) of the upper substrate 25. Further, an insulating film 26 as a liquid crystal layer thickness adjusting layer and a convex portion 28 in the same layer as the insulating film 26 are formed in the reflective display region R and the transmissive display region T, respectively, on the inner surface side. Also in this case, the insulating film 26 is formed with a concave portion 29 having a concave surface.

  In such a liquid crystal display device 200, as in the liquid crystal display device 100 of the first embodiment, it is possible to efficiently control the alignment of liquid crystal molecules. In particular, in the liquid crystal display device 200 of the present embodiment, since the insulating film 26 that is the liquid crystal layer thickness adjusting layer is formed on the upper substrate 25 side, the insulating film for imparting irregularities to the reflective film 20 It becomes easy to form a concave shape and a convex shape of a desired shape without being affected by the 24 uneven shapes. That is, since the insulating film 26 and the convex portion 28 can be formed on a relatively flat surface as compared with the first embodiment, the forming process is facilitated.

[Third Embodiment]
The third embodiment of the present invention will be described below with reference to the drawings.
FIG. 6 is a schematic view corresponding to FIG. 3 of the first embodiment, showing a plan view and a sectional view of the liquid crystal display device 300 of the third embodiment. The basic configuration of the liquid crystal display device of the present embodiment is the same as that of the first embodiment, and a plurality of convex portions 28 are formed in the transmissive display region T, and the convex portions are also formed on the upper substrate 25 side. The difference is that 30 is formed. Therefore, in FIG. 6, the same reference numerals are given to the same components as those in FIG. 3, and detailed description is omitted.

  As shown in FIG. 6, in the liquid crystal display device 300 of the third embodiment, one convex portion 28 that regulates alignment of liquid crystal molecules is provided on the inner surface side of the lower substrate 10 in the transmissive display region T. A plurality of (two in this embodiment) are formed within one dot, and a convex portion 30 is formed on the opposite side, that is, on the upper substrate 25 side, so as to be positioned between adjacent convex portions 28, 28. Has been. In other words, in the transmissive display region T, the convex portions 28, 30, 28 are alternately formed so that the upper substrate 25 and the lower substrate 10 are in alternate positions. In this case, the cell thickness (liquid crystal layer thickness) of the transmissive display region T is about 4 μm, and the height of the convex portion 30 formed on the upper substrate 25 side (height protruding from the inner surface of the substrate into the liquid crystal layer 50). Is about 1.5 μm.

  In such a liquid crystal display device 300 as well, it is possible to efficiently control the alignment of liquid crystal molecules as in the liquid crystal display device 100 of the first embodiment. In particular, in the present embodiment, the convex portions 28, 28, and 30 serving as liquid crystal molecule alignment regulating means are formed on both of the pair of substrates 10 and 25, and are alternately positioned in a plane. In other words, the convex portion 30 is formed on the inner surface of the upper substrate 25 so as to be positioned between the adjacent convex portions 28 on the lower substrate 10, so that the alignment division can be performed more efficiently. Can be done.

  As shown in FIG. 7, the tilt of the liquid crystal molecules whose orientation is regulated by each of the convex portions 28, 30, 28 by the convex portions 28, 30, 28 arranged at positions that are staggered in the plane as described above. The direction is the same between adjacent convex portions, and a portion where the liquid crystal molecules are discontinuous is not formed. The convex portions 28 and 28 formed on the lower substrate 10 side are formed by the same manufacturing process as the insulating film 26, and the convex portion 30 formed on the upper substrate 25 side is formed on the electrode 31. It is assumed that it is formed alone by a photolithography method or the like.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 8 is a schematic view corresponding to FIG. 3 of the first embodiment, showing a plan view and a cross-sectional view of the liquid crystal display device 400 of the fourth embodiment. The basic configuration of the liquid crystal display device of the present embodiment is the same as that of the first embodiment, and a plurality of convex portions 28 are formed in the transmissive display region T, and the convex portions are also formed on the upper substrate 25 side. 30 in that the slit 48 is formed in the electrode 31 on the opposite side of the concave portion 29 of the reflective display region R. Therefore, in FIG. 8, the same reference numerals are given to the same components as those in FIG. 3, and the detailed description is omitted.

  As shown in FIG. 8, in the liquid crystal display device 400 of the fourth embodiment, one convex portion 28 for regulating the alignment of liquid crystal molecules is provided on the inner surface side of the lower substrate 10 in the transmissive display region T. A plurality of (two in this embodiment) are formed within one dot, and a convex portion 30 is formed on the opposite side, that is, on the upper substrate 25 side, so as to be positioned between adjacent convex portions 28, 28. Has been. In other words, in the transmissive display region T, the convex portions 28, 30, 28 are alternately formed so that the upper substrate 25 and the lower substrate 10 are in alternate positions. The cell thickness (liquid crystal layer thickness) of the transmissive display region T is about 4 μm, and the height of the convex portion 30 formed on the upper substrate 25 side (the height protruding from the inner surface of the substrate into the liquid crystal layer 50) is about 1. .5 μm.

  Further, in the insulating film 26 in the reflective display region R, a concave portion 29 is formed as in the liquid crystal display device 100 of the first embodiment, and the electrode formed on the opposite side, that is, on the inner surface side of the upper substrate 25. A slit 48 is formed in 31 for the purpose of regulating the alignment of liquid crystal molecules. The slit 48 is formed to face the concave portion 29 of the insulating film 26 and has a shape in which a part of the electrode 31 is partially cut away.

  In such a liquid crystal display device 400, as in the liquid crystal display device 100 of the first embodiment, it is possible to efficiently control the alignment of liquid crystal molecules. In particular, in the present embodiment, the convex portions 28, 28, and 30 serving as liquid crystal molecule alignment regulating means are formed on both of the pair of substrates 10 and 25, and are alternately positioned in a plane. In other words, since the convex portion 30 is formed on the inner surface of the upper substrate 25 so as to be positioned between the adjacent convex portions 28 on the lower substrate 10, as in the third embodiment, the height is further increased. It becomes possible to perform alignment division efficiently.

  Further, in the liquid crystal display device 400 of the present embodiment, the slit 48 is formed in the electrode 31, and the electric field between the electrodes 31 and 9 is distorted to generate an oblique electric field. The tilt direction based on the applied voltage of the liquid crystal molecules is restricted. In addition, since the tilt direction of the liquid crystal molecules based on the oblique electric field is the same as the tilt direction of the liquid crystal molecules regulated by the concave portions 29 formed to face each other, the alignment control of the liquid crystal molecules is more reliably performed. It becomes possible. In the reflective display region R, since the insulating film 26 is formed to reduce the thickness of the liquid crystal layer, it is relatively difficult to form the convex portion. By forming slits, the alignment of liquid crystal molecules can be regulated easily and reliably.

[Fifth Embodiment]
The fifth embodiment of the present invention will be described below with reference to the drawings.
FIG. 9 is a schematic view corresponding to FIG. 3 of the first embodiment, showing a plan view and a cross-sectional view of the liquid crystal display device 500 of the fifth embodiment. The basic configuration of the liquid crystal display device of the present embodiment is the same as that of the first embodiment. A plurality of convex portions 28a are formed in the transmissive display region T, and the convex portions are also formed on the upper substrate 25 side. 30a is formed, and a slit 48 is formed in the electrode 31 on the opposite side of the concave portion 29 of the reflective display region R, and the convex portions 28a, 28a, and 30a are disposed in the opening formed in the electrode. Is different. Therefore, in FIG. 9, the same reference numerals are given to the same components as those in FIG. 3, and detailed description thereof is omitted.

  As shown in FIG. 9, in the liquid crystal display device 500 of the fifth embodiment, one convex portion 28 a that regulates the alignment of liquid crystal molecules is provided on the inner surface side of the lower substrate 10 in the transmissive display region T. A plurality of (two in this embodiment) are formed in one dot, and a convex portion 30a is formed on the opposite side, that is, on the upper substrate 25 side so as to be positioned between adjacent convex portions 28a, 28a. Has been. That is, in the transmissive display region T, the convex portions 28a, 30a, and 28a are alternately formed so that the upper substrate 25 and the lower substrate 10 are in alternate positions.

  Further, in the insulating film 26 in the reflective display region R, a concave portion 29 is formed as in the liquid crystal display device 100 of the first embodiment, and the electrode formed on the opposite side, that is, on the inner surface side of the upper substrate 25. A slit 48 is formed in 31 for the purpose of regulating the alignment of liquid crystal molecules. The slit 48 is formed to face the concave portion 29 of the insulating film 26 and has a shape in which a part of the electrode 31 is partially cut away.

  Further, the common electrode 9 is provided with openings corresponding to the convex portions 28a and 28a disposed in the transmissive display region T, that is, the common electrode 9 is provided on the convex portions 28a and 28a of the transmissive display region T. 9 was not present. Further, the pixel electrode 31 does not exist on the convex portion 30 a with respect to the pixel electrode 31. In order to obtain a configuration in which no electrode exists on the convex portions 28a and 30a in this way, for example, a mask may be formed at the position where the convex portion is formed when the electrode is formed.

  In such a liquid crystal display device 500, as in the liquid crystal display device 100 of the first embodiment, the alignment control of liquid crystal molecules can be performed efficiently. In particular, in the present embodiment, convex portions 28, 28, 30 serving as liquid crystal molecule alignment regulating means are formed on both of the pair of substrates 10, 25 so that they are alternately positioned in a plane. In other words, since the convex portion 30 is formed on the inner surface of the upper substrate 25 so as to be positioned between the adjacent convex portions 28 on the lower substrate 10, as in the third embodiment, higher efficiency is achieved. It is possible to perform orientation division.

  Further, since the slit 48 is formed in the electrode 31, the electric field between the electrodes 31 and 9 is distorted to generate an oblique electric field, and the tilt direction based on the voltage application of the liquid crystal molecules vertically aligned in the initial state is changed according to the oblique electric field. It will be regulated. In addition, since the tilt direction of the liquid crystal molecules based on the oblique electric field is the same as the tilt direction of the liquid crystal molecules regulated by the concave portions 29 formed to face each other, the alignment control of the liquid crystal molecules is more reliably performed. It becomes possible.

  Further, in the present embodiment, since the electrode is not formed on the convex portions 28a, 28a, 30a, the following effects are produced. That is, as schematically shown in FIG. 10A, when the electrodes 9 and 31 are formed on the convex portions 28 and 30, the direction in which the liquid crystal molecules fall and the direction of the electric lines of force are inclined to the same side. The force for controlling the alignment of liquid crystal molecules is reduced. However, as schematically shown in FIG. 10B, when the electrodes 9 and 31 are not formed on the convex portions 28a and 30a, the direction in which the liquid crystal molecules fall and the direction of the lines of electric force are opposite to each other. Since the liquid crystal molecules are inclined, the direction in which the liquid crystal molecules are tilted is easily determined, and the liquid crystal molecules can be more stably regulated.

[Sixth Embodiment]
Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings.
FIG. 11 is a schematic view corresponding to FIG. 3 of the first embodiment, showing a plan view and a cross-sectional view of the liquid crystal display device 600 of the sixth embodiment. The basic configuration of the liquid crystal display device of this embodiment is the same as that of the first embodiment, except that slits 49a and 49b are formed on the common electrode 9 formed on the insulating film 26. Yes. Therefore, in FIG. 11, the same reference numerals are given to the same components as those in FIG. 3, and detailed description is omitted.

  As shown in FIG. 11, in the liquid crystal display device 600 of the sixth embodiment, a concave portion is formed on the insulating film 26 formed in the reflective display region R, as in the liquid crystal display device 100 of the first embodiment. On the other hand, slits 49 a and 49 b are formed around the concave portion 29 with respect to the common electrode 9 disposed on the insulating film 26.

  In the liquid crystal display device 600 of this embodiment, in the reflective display region R, the tilt direction of the liquid crystal molecules is restricted by the concave portion 29 and the electrode slits 49a and 49b. In the slits 49a and 49b, the liquid crystal molecules fall in directions opposite to each other when viewed from the center. Accordingly, the tilt direction of the liquid crystal molecules continuously changes in the concave portion 29 and the electrode slits 49a and 49b, and the alignment regulation of the liquid crystal molecules is performed with higher efficiency.

  As in the liquid crystal display device 700 shown in FIG. 12, two concave portions 29a and 29b are formed in the insulating film 26 in the reflective display region R, and an electrode slit 49 is formed between the concave portions 29a and 29b. Even in the case of formation, the alignment of liquid crystal molecules can be regulated with higher efficiency in the reflective display region R in the same manner as described above.

[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. 13 is a perspective view showing an example of a mobile phone. In FIG. 13, reference numeral 1000 denotes a mobile phone body, and reference numeral 1001 denotes a display unit using the liquid crystal display device. When the liquid crystal display device according to any of the above embodiments is used as a display unit of such an electronic device such as a mobile phone, an electronic device provided with a liquid crystal display unit that is bright, has high contrast, and has a wide viewing angle regardless of the use environment. Equipment can be realized.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, an example in which the present invention is applied to an active matrix liquid crystal display device using a TFD as a switching element has been described. However, in addition to an active matrix liquid crystal display device using a TFT as a switching element, a passive matrix liquid crystal display device is used. The present invention can also be applied to a display device or the like.

1 is an equivalent circuit diagram of a liquid crystal display device according to a first embodiment of the present invention. FIG. 2 is a schematic plan view showing the electrode configuration of the liquid crystal display device. The plane schematic diagram and cross-sectional schematic diagram which show the principal part of a liquid crystal display device. Explanatory drawing for showing an effect | action of the liquid crystal display device of 1st Embodiment. The plane schematic diagram and cross-sectional schematic diagram which show the principal part of the liquid crystal display device of 2nd Embodiment. The plane schematic diagram and cross-sectional schematic diagram which show the principal part of the liquid crystal display device of 3rd Embodiment. Explanatory drawing for demonstrating the effect | action of the liquid crystal display device of 3rd Embodiment. The plane schematic diagram and cross-sectional schematic diagram which show the principal part of the liquid crystal display device of 4th Embodiment. The plane schematic diagram and cross-sectional schematic diagram which show the principal part of the liquid crystal display device of 5th Embodiment. Explanatory drawing for demonstrating the effect | action of the liquid crystal display device of 5th Embodiment. The plane schematic diagram and cross-sectional schematic diagram which show the principal part of the liquid crystal display device of 6th Embodiment. FIG. 13 is a schematic plan view and a schematic cross-sectional view illustrating a modification of the liquid crystal display device of FIG. 12. 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, 10 ... TFT array substrate (substrate), 10A ... Substrate body (substrate), 20 ... Reflective film, 22 ... Color filter layer, 24 ... Insulating film, 25 ... Opposite substrate, 25A ... Substrate body (substrate) , 26 ... insulating film (liquid crystal layer thickness adjusting layer), 28 ... convex part, 29 ... concave part, 31 ... pixel electrode, 50 ... liquid crystal layer, R ... reflective display area, T ... transmissive display area, D1, D2, D3 ... dot area

Claims (5)

A liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of substrates, and a transmissive display region for performing transmissive display and a reflective display region for performing reflective display are provided in one dot region,
The liquid crystal layer is made of a liquid crystal having negative dielectric anisotropy,
In the reflective display area and the transmissive display area, an insulating layer made of the same material and having a predetermined pattern is formed.
In the reflective display region, the insulating layer is configured as a liquid crystal layer thickness adjusting layer for making the liquid crystal layer thickness of the reflective display region smaller than the liquid crystal layer thickness of the transmissive display region, while the transmissive display region Is configured as a convex portion for controlling the alignment of the liquid crystal molecules of the liquid crystal layer protruding toward the liquid crystal layer side ,
The insulating layer formed in the reflective display region has a concave portion for controlling the alignment of the liquid crystal molecules of the liquid crystal layer, the surface of the insulating layer being partially recessed. apparatus. In the substrate on the side facing the substrate on which the liquid crystal layer thickness adjusting layer is formed, an electrode is formed at a position facing the concave portion,
The liquid crystal display device according to claim 1 , wherein the electrode is formed with a slit formed by partially cutting the electrode at a position facing the concave portion. On one side of the pair of substrates opposite to the liquid crystal layer, a backlight for transmissive display is provided,
A reflective film selectively formed in the reflective display region is provided on the liquid crystal layer side of the one substrate,
The liquid crystal display device according to claim 1 , wherein an unevenness providing layer for providing an uneven shape to the reflective film is formed in the reflective display region. 4. The liquid crystal display device according to claim 1, wherein an electrode having an opening is formed on the convex portion in the substrate on which the convex portion is formed. An electronic apparatus comprising the liquid crystal display device according to claim 1 .

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