JP2009237019A - Liquid crystal display device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of obtaining fine display in both of reflective display and transmissive display. <P>SOLUTION: In the liquid crystal display device 10, a reflective display part R on the liquid crystal layer 52 side of a first substrate 48 includes a reflection film 30 on the surface of which on the liquid crystal layer 52 side is provided with a first rugged shape 30a, and a first resin layer 64 which is formed on the liquid crystal layer 52 side of the reflection film 30 and on the surface of which in contact with the liquid crystal layer 52 is provided with the first rugged shape 30a. The reflective display part R on the liquid crystal layer 52 side of a second substrate 50 includes a second resin layer 68 on the surface which in contact with the liquid crystal layer 52 is provided with a second rugged shape 62a. The first rugged shape 30a and the second rugged shape 62a are arranged so that the projected portions of the second rugged shape 62a correspond to the recessed portions of the first rugged shape 30a and the recessed portions of the second rugged shape 62a correspond to the projected portions of the first rugged shape 30a in plane view, and the first rugged shape 30a and the second rugged shape 62a are in a plane symmetrical relation and respective rugged shapes are inverted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  At present, transmissive liquid crystal display devices with a wide viewing angle, such as an IPS (In Plane Switching) system and a VA (Vertical Alignment) system, are widely used as monitors, and they are also used as televisions with improved response characteristics. On the other hand, liquid crystal display devices are widely used in portable information devices such as mobile phones and digital cameras. Portable information devices are mainly used by individuals, but recently, the number of display units with variable angles is increasing, and a wide viewing angle is desired because they are often observed from an oblique direction.

  A liquid crystal display device for a portable information device is used in various environments including outdoors from a sunny day to a dark room. Therefore, it is desired to be a transflective type. The transflective liquid crystal display device has a reflective display portion and a transmissive display portion in one pixel. The reflective display unit uses a reflective film to reflect the incident light from the surroundings, and the contrast ratio is constant regardless of the surrounding brightness, so it is a relatively bright environment from the outdoors to the room in fine weather. Good display is obtained below. Since the transmissive display unit uses a backlight and has a constant luminance regardless of the environment, a display with a high contrast ratio can be obtained in a relatively dark environment from indoors to a dark room. A transflective liquid crystal display device having both of these features can display a high contrast ratio in a wide range of environments including outdoors from a sunny day to a dark room.

  Current transflective liquid crystal display devices are generally of a homogeneous alignment method and a vertical alignment method. However, since this configuration uses a plurality of retardation films, the contrast of the transmissive display unit and the viewing angle are reduced.

  Therefore, a transflective display method with a wide viewing angle has been proposed by replacing the FFS (Fringe Field Switching) method known for transmissive display with a wide viewing angle with a transflective type (see, for example, Patent Document 1). . In Patent Document 1, a retardation film is provided only on the reflective display portion, and a high contrast reflective display is realized while maintaining a wide viewing angle equivalent to the transmissive type. At this time, the retardation of the liquid crystal layer in the reflective display unit is set to ¼ wavelength. In general, the reflective film in the reflective display portion has a concavo-convex shape, whereby light incident from various angles can be reflected to the front.

JP 2005-338256 A

  However, a liquid crystal layer thickness (cell gap) difference of about 1 μm occurs due to the uneven shape of the reflective film. As a result, a portion where the retardation does not reach the optimum λ / 4 wavelength is generated, so that the reflectance during black display is increased and the overall contrast is lowered. This is one of the causes of contrast reduction in the reflective display section.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A liquid crystal layer is sandwiched between a first substrate and a second substrate, and an electric field is generated between the first electrode and the first electrode on the liquid crystal layer side of the first substrate. A first polarizing plate having a reflective display portion and a transmissive display portion in one pixel, and having transmission axes substantially orthogonal to each other outside the first substrate and the second substrate. And a second polarizing plate, and a transmission axis of one of the first polarizing plate and the second polarizing plate is a liquid crystal display device set substantially parallel to the liquid crystal alignment direction of the liquid crystal layer. The reflective display portion on the liquid crystal layer side of the first substrate is provided with a reflective film having a first concavo-convex shape on the surface on the liquid crystal layer side, and provided on the liquid crystal layer side of the reflective film, A first resin layer provided with the first concavo-convex shape on a surface in contact with the liquid crystal layer, and the second group The reflective display portion on the liquid crystal layer side is provided with a second resin layer having a second concavo-convex shape on the surface in contact with the liquid crystal layer, and the second concavo-convex concave portion has the second resin layer. The concave-convex portions of the second concave-convex shape are arranged corresponding to the convex portions of the concave-convex shape and the convex portions of the first concave-convex shape, respectively, and the first concave-convex shape and the second concave-convex shape are A liquid crystal display device characterized in that it has a symmetric uneven shape and is formed by inverting the uneven shape.

  According to this, the first concavo-convex shape is given to the surface of the first resin layer of the first substrate in contact with the liquid crystal layer in the reflective display portion, and the surface of the second resin layer of the second substrate is plane-symmetric. Since the second concavo-convex shape obtained by inverting the concavo-convex shape is provided, the cell gap is constant, variation in retardation due to the liquid crystal is suppressed, and high-contrast reflective display can be performed. . Therefore, it is possible to provide a liquid crystal display device that can obtain a good display in both the reflective display and the transmissive display.

  Application Example 2 In the liquid crystal display device, the retardation film provided between the second substrate and the second resin layer in the reflective display unit, the retardation film, and the second resin layer And a third resin layer provided with the second concavo-convex shape on the surface on the liquid crystal layer side.

  According to this, since the 1st uneven | corrugated shape is not provided to the surface of retardation film, manufacture is easy compared with the case where the 1st uneven | corrugated shape is provided to the surface of retardation film.

  Application Example 3 In the liquid crystal display device, a color filter layer provided on the liquid crystal layer side of the second substrate, and between the color filter layer and the second resin layer in the reflective display unit. A third resin layer provided with the second concavo-convex shape on the surface on the liquid crystal layer side, opposed to the reflective film, provided between the third resin layer and the second resin layer, A liquid crystal display device, further comprising: a retardation film having the first uneven shape on the surface opposite to the liquid crystal layer and the second uneven shape on the surface on the liquid crystal layer side. .

  According to this, although the retardation film itself is made of a liquid crystal resin, it is difficult to photo-process it as it is, and the film thickness becomes non-uniform, so that the retardation film is formed on the third resin layer. By providing the film, it becomes easy to make the thickness of the retardation film uniform.

  Application Example 4 In the liquid crystal display device, the black matrix layer provided on the liquid crystal layer side of the second substrate, and the color filter layer and the black matrix on the liquid crystal layer side of the second substrate. A liquid crystal display device, wherein the third resin layer is the flattening layer.

  According to this, it is possible to provide the third resin layer exclusively for the formation of unevenness, but in general, the second substrate is provided with the color filter layer and the black matrix layer. A flattening layer is provided for the purpose of covering the resulting step. By using this flattening layer as the third resin layer, the second uneven shape is provided without providing an additional layer for forming the unevenness.

  Application Example 5 Electronic equipment comprising the liquid crystal display device described above.

  According to this, since the liquid crystal display device is mounted, an electronic apparatus having excellent display quality can be provided.

  Hereinafter, an embodiment of a liquid crystal display device will be described with reference to the drawings. In the drawings referred to in each embodiment, each layer and each member are displayed in different scales so that each layer and each member have a size that can be recognized on the drawing.

(First embodiment)
FIG. 1 is a circuit configuration diagram of a plurality of pixel regions formed in a matrix that constitutes the liquid crystal display device 10 according to the present embodiment.
The liquid crystal display device 10 of this embodiment controls the alignment of liquid crystal molecules in the liquid crystal layer using a liquid crystal driving electric field (lateral electric field or oblique electric field method) generated between different electrodes provided on the liquid crystal layer side of the same substrate. This is a liquid crystal display device adopting the FFS method for displaying an image. In addition, a color liquid crystal display device having a color filter layer on a substrate, which includes three pixels that output R (red), G (green), and B (blue) light as transmitted light or reflected light. One color pixel is configured. Therefore, a display area that is a minimum unit constituting the display is referred to as a “pixel area”.

  The liquid crystal display device 10 constitutes an image display area by a plurality of pixel areas formed in a matrix. Each of the plurality of pixel regions is provided with a pixel electrode (first electrode) 12 and a TFT (Thin Film Transistor) 14 (or TFD (Thin Film Diode)) for switching control of the pixel electrode 12. The data line 18 extending from the data line driving circuit 16 is electrically connected to the source of the TFT 14. The data line driving circuit 16 supplies the image signals S1, S2,..., Sn to each pixel via the data line 18. The image signals S1 to Sn may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 18.

  Further, a scanning line 22a extending from the scanning line driving circuit 20 is electrically connected to the gate of the TFT 14, and the scanning signal G1 is supplied from the scanning line driving circuit 20 to the scanning line 22a in a pulse manner at a predetermined timing. , G2,..., Gm are applied to the gate of the TFT 14 in the order of lines in this order. The pixel electrode 12 is electrically connected to the drain of the TFT 14. The TFT 14 serving as a switching element is turned on for a certain period by the input of scanning signals G1, G2,..., Gm, so that the image signals S1, S2,. Writing is performed on the pixel electrode 12.

  Image signals S1, S2,..., Sn written to the liquid crystal via the pixel electrode 12 are held for a certain period between the pixel electrode 12 and the common electrode (second electrode). Here, in order to prevent the held image signal from leaking, a storage capacitor 24 is provided in parallel with the liquid crystal capacitor provided between the common electrode and the pixel electrode 12. The storage capacitor 24 is provided between the drain of the TFT 14 and the capacitor line 22b. Thus, the TFT 14 is provided in the vicinity of the intersection between the data line 18 and the scanning line 22a.

Next, a detailed configuration of the liquid crystal display device 10 will be described with reference to FIGS.
FIG. 2 is a plan configuration diagram in an arbitrary one pixel region of the liquid crystal display device 10 according to the present embodiment. 3 is a partial cross-sectional configuration diagram taken along line III-III in FIG. FIG. 4 is a cross-sectional view illustrating the first uneven shape. FIG. 5 is a partial cross-sectional configuration diagram taken along the line V-V in FIG. 2.
As shown in FIG. 2, the pixel region of the liquid crystal display device 10 has a plurality of slit-like openings 26, and is longitudinal in the y-axis direction (data line 18 / extension direction of a wiring for supplying a signal) ( A pixel electrode 12 having a long side direction) and a substantially flat solid common electrode (second electrode) 28 disposed so as to overlap the pixel electrode 12 in a plane are provided. The illustrated pixel region is partitioned into a reflective display portion R and a transmissive display portion T. The reflective display portion R includes a reflective film 30 provided partially (selectively) within the pixel region, and A retardation film 32 is disposed so as to overlap the reflective film 30 in plan view. A portion where the reflective film 30 is provided is a reflective display portion R, and the other portion is a transmissive display portion T.

  The pixel electrode 12 is provided with a plurality of slit-like openings 26 extending at an angle of 5 ° counterclockwise with respect to the x-axis direction (scanning line 22a / extending direction of the wiring for supplying a signal). The pixel electrode 12 is formed of a conductive film made of a light transmissive conductive material such as ITO (indium tin oxide).

The common electrode 28 is provided across the transmissive display portion T and the reflective display portion R. The common electrode 28 is provided so as to cover the reflective film 30 partially provided in the pixel region. The common electrode 28 is a conductive film made of a light transmissive conductive material such as ITO, and the reflective film 30 is a metal film made of a light reflective material such as aluminum or silver, or a dielectric film (SiO ₂ having a different refractive index). And TiO ₂ etc.) are formed of a dielectric laminated film (dielectric mirror).

  In the pixel region, a data line 18 extending in the y-axis direction, a scanning line 22a extending in the x-axis direction, and a capacitor line 22b extending adjacent to the scanning line 22a and parallel to the scanning line 22a are provided. A TFT 14 is provided in the vicinity of the intersection of the data line 18 and the scanning line 22a. The TFT 14 includes a semiconductor layer 34 made of amorphous silicon partially provided in the planar region of the scanning line 22a, a source electrode 36 and a drain electrode 38 partially overlapped with the semiconductor layer 34 in plan view. Yes. The scanning line 22a functions as a gate electrode of the TFT 14 at a position overlapping the semiconductor layer 34 in a plan view. The pixel electrode 12 and the TFT 14 are coupled by a contact hole 40. A black matrix layer 42 is provided so as to cover the TFT 14, the data line 18, and the scanning line 22a. A color filter layer 44 bordered by the black matrix layer 42 is arranged for each pixel region.

  As shown in FIG. 3, the liquid crystal display device 10 has a configuration in which a liquid crystal layer 52 is sandwiched between an array substrate (first substrate) 48 and a counter substrate (second substrate) 50 that are arranged to face each other. ing. The liquid crystal layer 52 is a region where the array substrate 48 and the counter substrate 50 are opposed to each other, and is provided between the substrates 48 and 50 by a sealing material (not shown) provided along the edges of the substrates 48 and 50. Is sealed. The liquid crystal molecules 46 (see FIG. 2) of the liquid crystal layer 52 are liquid crystal compositions exhibiting positive dielectric anisotropy in which the dielectric constant in the alignment direction is larger than the normal direction. The liquid crystal molecules 46 are anti-parallel rubbed in parallel and anti-parallel to the x axis, and the liquid crystal alignment is homogeneous. A backlight (illuminating device) (not shown) is provided on the side opposite to the liquid crystal layer 52 of the array substrate 48 (back side / lower side in the figure).

  The array substrate 48 has a substrate body 48a made of glass, quartz, plastic, or the like as a base, and a scanning line 22a and a capacitor line 22b (see FIG. 2) are provided on the substrate body 48a on the liquid crystal layer 52 side. A gate insulating film 54 is provided to cover the scanning line 22a and the capacitor line 22b.

  A semiconductor layer 34 (see FIG. 2) is provided on the liquid crystal layer 52 side of the gate insulating film 54, and a source electrode 36 (see FIG. 2) and a drain electrode 38 (see FIG. 2) so as to partially run over the semiconductor layer 34. 2). The semiconductor layer 34 is disposed to face the scanning line 22a via the gate insulating film 54, and the scanning line 22a forms a gate electrode of the TFT 14 (see FIG. 2) in the facing region.

  A first interlayer insulating film 56 made of silicon oxide or the like is provided so as to cover the semiconductor layer 34, the source electrode 36, and the drain electrode 38. On the liquid crystal layer 52 side of the first interlayer insulating film 56, acrylic or the like is formed. A planarizing layer 58 is provided.

  A base layer 59 is provided on the liquid crystal layer 52 side of the planarizing layer 58. The underlayer 59 is provided on the liquid crystal layer 52 side of the array substrate 48. The underlayer 59 may be provided only in the reflective display portion R for each pixel region. A first uneven shape 30 a is provided on the surface of the reflective display portion R on the liquid crystal layer 52 side of the base layer 59. For example, as shown in FIG. 4, the thickness of the underlayer 59 is 2 μm, and the top of the uneven surface is located 0.3 μm inside from the surface of the underlayer 59, as shown in FIG. The deepest portion is 0.7 μm deep from the top of the concavo-convex surface, and the average depth of the concavo-convex region is 0.25 μm. The foundation layer 59 is a resin layer.

  The reflective film 30 is provided in a partial region of the base layer 59 on the liquid crystal layer 52 side. The reflective film 30 is provided on the reflective display portion R for each pixel region on the liquid crystal layer 52 side of the array substrate 48. The surface of the reflective film 30 on the liquid crystal layer 52 side reflects the uneven shape of the base layer 59 and is provided with a first uneven shape 30a.

  As shown in FIG. 2, the reflective film 30 is provided in a planar region that is close to the TFT 14 in the pixel region, and corresponds to the region where the reflective film 30 is formed (overlapping when viewed in plan). A reflection display portion R is configured in the region. As described above, the reflective film 30 is planarly disposed on the TFT 14 side in which the long side of the pixel region is divided into two in the pixel region, and is disposed on the short side end of the pixel region in which the TFT 14 is disposed. Yes. Therefore, of the planar area of the pixel area, the planar area where the reflective film 30 overlaps in plan is the reflective display portion R of the pixel area, and the remaining area is the transmissive display portion T. As the reflective film 30, it is preferable to use a film provided with an uneven shape on its surface and imparted with light scattering properties. With such a configuration, the visibility in reflective display can be improved.

  Returning to FIG. 3, the common electrode 28 is provided so as to cover the reflective film 30. The common electrode 28 is a flat solid conductive film and is provided over the entire surface of the pixel region. The common electrode 28 is provided for each pixel region on the liquid crystal layer 52 side of the array substrate 48. The surface of the common electrode 28 on the liquid crystal layer 52 side reflects the first concavo-convex shape 30a on the reflective film 30, and is provided with the first concavo-convex shape 30a.

  A second interlayer insulating film 60 made of silicon oxide or the like is provided so as to cover the common electrode 28. On the surface of the second interlayer insulating film 60 on the liquid crystal layer 52 side, the first uneven shape 30a on the common electrode 28 is reflected, and the first uneven shape 30a is given.

  The pixel electrode 12 is provided on the liquid crystal layer 52 side of the second interlayer insulating film 60. On the surface of the pixel electrode 12 on the liquid crystal layer 52 side, the first uneven shape 30a on the second interlayer insulating film 60 is reflected, and the first uneven shape 30a is given. The pixel electrode 12 is a conductive film having a plurality of slit-like openings 26. The pixel electrode 12 is provided on the liquid crystal layer 52 side of the array substrate 48 and is disposed so as to overlap the common electrode 28 in a plan view. In other words, the pixel electrode 12 is provided in a region overlapping the common electrode 28 in a plan view and is disposed via the insulating film. When a voltage is applied between the pixel electrode 12 and the common electrode 28 having the above-described configuration, the pixel electrode 12 and the common electrode 28 mainly pass through the opening 26 of the pixel electrode 12 with respect to the y-axis direction. A planar liquid crystal driving electric field having an angle of 5 ° counterclockwise is formed. Only the array substrate 48 is provided with an electrode structure.

  A horizontal alignment film (first resin layer) 64 made of polyimide, silicon oxide, or the like is provided so as to cover the pixel electrode 12 and the second interlayer insulating film 60. The horizontal alignment film 64 is provided in contact with the liquid crystal layer 52. The horizontal alignment film 64 is formed by sputtering or the like. On the surface of the horizontal alignment film 64 on the liquid crystal layer 52 side, the first uneven shape 30a on the pixel electrode 12 and the second interlayer insulating film 60 is reflected, and the first uneven shape 30a is given.

  On the other hand, the counter substrate 50 has a substrate body 50a made of glass, quartz, plastic or the like as a base, and a color filter layer 44 is provided on the liquid crystal layer 52 side of the substrate body 50a. The color filter layer 44 has a plurality of types of colored layers having different colors, and a black matrix layer 42 (see FIG. 2) made of a black resin or the like is provided between the color filter layers 44 having different color types. Has been placed.

  The color filter layer 44 is mainly composed of a color material layer corresponding to the display color of each pixel. However, the color filter layer 44 may be divided into two or more regions having different chromaticities in the pixel region. For example, a configuration provided individually in a first color material region provided corresponding to the planar region of the transmissive display portion T and a second color material region provided corresponding to the planar region of the reflective display portion R Can be adopted. In this case, by making the chromaticity of the first color material region larger than the chromaticity of the second color material region, the display light is transmitted twice, and the transmissive display unit T that transmits the color filter layer 44 only once. It is possible to prevent the chromaticity of the display light from being different from that of the reflective display portion R, and to match the appearance of the transmissive display and the reflective display.

  A flattening layer 66 is provided on the color filter layer 44 on the liquid crystal layer 52 side. The flattening layer 66 is provided on the counter substrate 50 on the liquid crystal layer 52 side in order to flatten the step between the color filter layer 44 and the black matrix layer 42. Thereby, the thickness of the liquid crystal layer 52 is made uniform, and it is possible to prevent the drive voltage from becoming non-uniform in the pixel region and lowering the contrast. The planarization layer 66 also functions as a base layer for the retardation film 32.

  A retardation film 32 is provided on the reflective display portion R on the liquid crystal layer 52 side of the flattening layer 66. The retardation film 32 is provided in the reflective display portion R facing the reflective film 30 on the liquid crystal layer 52 side of the counter substrate 50. The retardation film 32 gives a phase difference of approximately ½ wavelength (λ / 2) to light having a vibration direction parallel to the optical axis direction (slow axis direction). This is a so-called inner surface retardation film provided on the liquid crystal layer 52 side. The retardation film 32 can be formed by a method in which a polymer liquid crystal solution or a liquid crystal monomer solution is applied onto an alignment film and is oriented in a predetermined direction when dried and solidified. The retardation film 32 is formed, for example, by aligning a liquid crystal having a photofunctional group in a predetermined direction and then fixing the light. Here, the phase difference is 280 nm, and the slow axis forms an angle of 67.5 ° with respect to the x-axis direction.

  A resin layer (third resin layer) 62 is provided on the liquid crystal layer 52 side of the retardation film 32. The surface of the resin layer 62 on the liquid crystal layer 52 side is provided with a second uneven shape 62a. The convex portions of the second concave / convex shape 62a are arranged in correspondence with the concave portions of the first concave / convex shape 30a, and the concave portions of the second concave / convex shape 62a are arranged in correspondence with the convex portions of the first concave / convex shape 30a, respectively. The first concavo-convex shape 30a and the second concavo-convex shape 62a are plane-symmetric concavo-convex shapes, and are formed by inverting the concavo-convex shape. As shown in FIG. 5, the resin layer 62 has a thickness of the liquid crystal layer 52 in the reflective display portion R set smaller than that of the liquid crystal layer 52 in the transmissive display portion T.

  The liquid crystal display device 10 according to the present embodiment reflects the reflection in the planar area in which the planar area including the pixel electrode 12 and the planar area provided with the common electrode 28 are overlapped in one pixel area shown in FIG. The region excluding the region where the film 30 is formed is a transmissive display portion T that performs display by modulating the light incident from the backlight and transmitted through the liquid crystal layer 52. In addition, a region where the planar region including the pixel electrode 12 and the planar region provided with the reflective film 30 overlap in a plane reflects light that is incident from the outside of the counter substrate 50 and passes through the liquid crystal layer 52. This is a reflective display portion R that performs modulation and display. In an area corresponding to the reflective display portion R, a retardation film 32 and a resin layer 62 for making the thickness of the liquid crystal layer 52 in the reflective display portion R thinner than the thickness of the liquid crystal layer 52 in the transmissive display portion T are selectively used. Is provided. In the transflective liquid crystal display device, incident light to the reflective display portion R is transmitted through the liquid crystal layer 52 twice, but incident light to the transmissive display portion T is transmitted through the liquid crystal layer 52 only once. As a result, if the retardation of the liquid crystal layer 52 is different between the reflective display portion R and the transmissive display portion T, a difference in light transmittance occurs, and a uniform image display cannot be obtained. Therefore, the reflective display portion R is provided with a reflective film 30 provided partially (selectively) within the pixel region, a retardation film 32 and a resin layer 62 disposed so as to overlap the reflective film 30 in a plane. Thus, a liquid crystal display device having a so-called multi-gap structure in which the cell gap of the liquid crystal layer 52 is made different between the reflective display portion R and the transmissive display portion T is obtained.

  Specifically, in the liquid crystal display device 10 of the present embodiment, the cell gap in the transmissive display portion T is 3.4 μm, and the cell gap in the reflective display portion R is the retardation film 32 and the resin layer 62 on the reflective display portion R. The thickness is 1.4 μm (Δnd = 140 nm) (the thickness of the retardation film 32 and the resin layer 62 is 2.0 μm). In other words, the thickness of the liquid crystal layer 52 in the reflective display portion R is set to about half the thickness of the liquid crystal layer 52 in the transmissive display portion T, and the retardation of the liquid crystal layer 52 in the reflective display portion R and the transmissive display portion T is It is set almost the same. Thereby, a uniform image display can be obtained in the reflective display portion R and the transmissive display portion T.

  A horizontal alignment film (second resin layer) 68 made of polyimide, silicon oxide, or the like is provided so as to cover the resin layer 62. The horizontal alignment film 68 is provided in contact with the liquid crystal layer 52. The horizontal alignment film 68 is formed by sputtering or the like. On the surface of the horizontal alignment film 68 on the liquid crystal layer 52 side, the second uneven shape 62a on the resin layer 62 is reflected, and the second uneven shape 62a is given. The horizontal alignment films 64 and 68 are anti-parallel rubbed in parallel and antiparallel to the x-axis so that the liquid crystal alignment becomes homogeneous alignment.

  First and second polarizing plates 70 and 72 are provided on the outer surface sides of the substrate bodies 48a and 50a, respectively. The transmission axis of the first polarizing plate 70 and the transmission axis of the second polarizing plate 72 are substantially orthogonal to each other.

Attention is paid to the transmissive display portion T of the liquid crystal display device 10 of the present embodiment configured as described above.
FIG. 6 is a diagram showing the arrangement of the optical axes of the liquid crystal display device 10 according to the present embodiment. The liquid crystal layer 52 has a homogeneous alignment, a first polarizing plate 70, and a second polarizing plate 72. When the liquid crystal alignment direction 74 is observed from the normal direction of the substrate, it is as shown in FIG. This figure is a top view of the transmissive display portion T observed from the normal direction on the array substrate 48 side after assembling the array substrate 48 and the counter substrate 50. Reference numeral 76 is drawn parallel to FIG. 2 so as to indicate the orientation of the data line 18. The liquid crystal molecules 46 are anti-parallel rubbed in parallel and anti-parallel to the x axis. The transmission axis 70 a of the first polarizing plate 70 and the transmission axis 72 a of the second polarizing plate 72 are orthogonal to each other, and the transmission axis 70 a is parallel to the liquid crystal alignment direction 74. Since this has the same configuration as that of the transmissive IPS system, a wide viewing angle that can withstand monitor use can be obtained for the transmissive display as in the transmissive IPS system.

  Next, paying attention to the reflective display portion R, the reflective display portion R includes a homogeneously oriented liquid crystal layer 52, a retardation film 32, and a second polarizing plate 72. FIG. 6B shows the relationship among the slow axis 32a of the retardation film 32, the liquid crystal alignment direction 74, and the transmission axis 72a of the second polarizing plate 72. Since the opening 26 of the pixel electrode 12 has an inclination of 5 ° with respect to the scanning line 22a, the main direction 78 of the electric field has an inclination of 5 ° with respect to the data line 18. When the azimuth angle is defined counterclockwise, the liquid crystal alignment direction 74 forms −95 ° with respect to the electric field direction. As a result, the effect of stabilizing the orientation change during voltage application and reducing the threshold voltage at which the orientation change occurs can be obtained. The slow axis 32a of the retardation film 32 and the transmission axis 72a of the second polarizing plate 72 form 67.5 ° and 90 ° with respect to the liquid crystal alignment direction 74, respectively.

  In addition, the retardation of the liquid crystal layer 52 and the retardation film 32 of the reflective display portion R is set to a quarter wavelength and a half wavelength, respectively. The laminate of the film 32 and the second polarizing plate 72 is a broadband circular polarizing plate. When no voltage is applied, the incident light is incident on the reflection film 30 in a circularly polarized state or a polarization state close to this in substantially the entire visible wavelength range. When the light enters the second polarizing plate 72 again after reflection, the vibration direction becomes linearly polarized light parallel to the absorption axis of the second polarizing plate 72, so that an achromatic dark display is obtained. The liquid crystal alignment direction 74 is not limited to the direction shown in FIG. 6, but is a direction that intersects the main direction 78 of the electric field generated between the pixel electrode 12 and the common electrode 28 (a direction that does not match). In the present embodiment, the main direction 78 of the electric field forms an angle of 5 ° with respect to the x-axis. The retardation film 32 is arranged in such a direction that the slow axis 32 a forms an angle of 67.5 ° with the transmission axis 72 a of the second polarizing plate 72. In this way, in the reflective display portion R, display with high contrast and a wide viewing angle can be realized by providing a necessary phase difference.

  In FIG. 6, the initial alignment direction of the liquid crystal in the liquid crystal layer 52 in the vicinity of the horizontal alignment films 64 and 68 is referred to as a liquid crystal alignment direction for convenience, but the horizontal alignment films 64 and 68 are initially liquid crystal by rubbing treatment. The alignment film is not limited to the one that defines the direction in which the molecules are aligned. For example, it may be an alignment film in which the initial alignment direction of the liquid crystal molecules is defined by photo-alignment or oblique deposition.

  FIG. 7 is a graph showing the relationship between the cell gap difference and the contrast of the liquid crystal display device 10 according to this embodiment. In a normal reflection film, a cell gap difference of about 1 μm is generated due to the uneven shape. As a result, a portion where the retardation does not become the optimal λ / 4 wavelength is generated, so that the reflectivity during black display is increased and the overall contrast is lowered as shown in FIG. In this embodiment, since the reflection contrast is the value within the frame 80 shown in FIG. 7 on all the surfaces in the pixel, an optimum λ / 4 wavelength can be obtained in any part of the concavo-convex shape. An optimum black reflectance can be obtained and the reflection contrast can be improved.

  According to this embodiment, by providing the resin layer 62 having the second concavo-convex shape 62a between the retardation film 32 and the liquid crystal layer 52 of the reflective display portion R, the cell gap becomes constant, and any portion of the concavo-convex shape is obtained. However, since the optimum λ / 4 wavelength can be obtained, the optimum black reflectance can be obtained on all surfaces, and the contrast of the reflective display portion R can be improved. Thereby, the dispersion | variation in the retardation by a liquid crystal is lose | eliminated and the liquid crystal display device 10 which performs reflective display with high contrast can be provided. Therefore, according to the liquid crystal display device 10 of the present embodiment, a good display can be obtained by both the reflective display and the transmissive display.

(Second Embodiment)
Next, a second embodiment will be described with reference to the drawings.
FIG. 8 is a schematic cross-sectional view showing the liquid crystal display device 90 according to the present embodiment, and shows a state when the liquid crystal display device 90 is cut along the column direction at a certain pixel. The liquid crystal display device 90 of the present embodiment is a TFT active matrix type transflective liquid crystal display device, similar to the liquid crystal display device 10 according to the first embodiment. The formation position of the layer 62 and the shape of the retardation film 32 are present. Accordingly, since the basic configuration of the liquid crystal display device 90 of the present embodiment is the same as that of the liquid crystal display device 10 of the first embodiment, common components are denoted by the same reference numerals, and detailed description thereof is omitted or simplified. To do.

  As shown in FIG. 8, the liquid crystal display device 90 of this embodiment has a configuration in which a liquid crystal layer 52 is sandwiched between an array substrate 48 and a counter substrate 50 that are arranged to face each other.

  The counter substrate 50 has a substrate body 50a as a base, and a color filter layer 44 and a black matrix layer 42 (see FIG. 2) are provided on the liquid crystal layer 52 side of the substrate body 50a. A resin layer 62 made of an insulating film is provided on the liquid crystal layer 52 side with the matrix layer 42 with a planarizing layer 66 interposed therebetween. The surface of the resin layer 62 on the liquid crystal layer 52 side is provided with a second uneven shape 62a. The resin layer 62 functions as a base layer for the retardation film 32.

  A phase difference film 32 made of an insulating film is provided on the liquid crystal layer 52 side of the resin layer 62. On the surface of the retardation film 32 opposite to the liquid crystal layer 52, the second uneven shape 62a on the resin layer 62 is reflected, and the first uneven shape 30a is given. On the surface of the retardation film 32 on the liquid crystal layer 52 side, the second uneven shape 62a on the resin layer 62 is reflected, and the second uneven shape 62a is given.

  A horizontal alignment film 68 made of polyimide, silicon oxide or the like is provided so as to cover the phase difference film 32. On the surface of the horizontal alignment film 68 on the liquid crystal layer 52 side, the second uneven shape 62a on the retardation film 32 is reflected, and the second uneven shape 62a is given.

  According to this, by providing the resin layer 62 having the second concavo-convex shape 62 a between the retardation film 32 of the reflective display portion R and the color filter layer 44, the cell gap becomes constant. The retardation film 32 itself is made of a liquid crystal resin, but it is difficult to photo-process it as it is and the film thickness becomes non-uniform, so that the retardation film 32 is formed on the resin layer 62. By providing, it becomes easy to make the thickness of the retardation film 32 uniform.

(Electronics)
FIG. 9 is a perspective view showing an example of an electronic apparatus according to the present embodiment. A cellular phone 100 shown in FIG. 9 includes the liquid crystal display device of the above-described embodiment as a small-sized display unit 102, and includes a plurality of operation buttons 104, an earpiece 106, and a mouthpiece 108.
The liquid crystal display device according to the embodiment is not limited to the mobile phone, but is an electronic book, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type or a monitor direct view type video tape recorder, a car navigation device, a pager, and an electronic notebook. , Calculators, word processors, workstations, videophones, POS terminals, and devices equipped with touch panels, etc., and can be suitably used as image display means. In any electronic device, high brightness, high contrast, wide viewing angle Transmission display and reflection display are possible.

  As mentioned above, although embodiment was described referring an accompanying drawing, it cannot be overemphasized that this embodiment is not limited to the example which concerns.

  For example, in the above-described embodiment, the common electrode 28 is a substantially planar electrode and the pixel electrode 12 includes the slit-shaped opening 26. However, the configuration of the electrode is not limited thereto, and the pixel electrode 12 is not limited thereto. The common electrode 28 may include a plurality of strip electrodes. That is, it is possible to adopt an electric field generation (lateral electric field) system in which the pixel electrode 12 and the common electrode 28 are adjacent to each other in the same layer in plan view. For example, each of the common electrode and the pixel electrode may be a substantially comb-like electrode in a plan view, and an electrode structure in which band-like electrodes constituting these comb-tooth portions are arranged to mesh with each other. Thus, even if the configuration of the electrode is changed, the same effect as that of the above embodiment can be obtained.

  In the present embodiment, the substrate on the side on which the backlight is incident is the array substrate 48, and the substrate on which the reflected light is incident (the substrate facing the substrate on which the reflective film 30 is provided) is the counter substrate 50. The reflective film 30 is disposed on the array substrate 48 side, and the retardation film 32 is disposed on the counter substrate 50 side. However, the substrate on which the backlight is incident is the counter substrate 50, the substrate on which the reflected light is incident is the array substrate 48, the reflective film 30 is disposed on the counter substrate 50 side, and the retardation film 32 is formed. The same characteristics can be obtained even when arranged on the array substrate 48 side.

  In the above embodiment, the pixel electrode 12 is configured as the upper electrode and the common electrode 28 is configured as the lower electrode. However, the configuration of the electrodes is not limited to this, and the lower electrode is configured as the pixel electrode 12 and the upper electrode is configured as the upper electrode. Similar characteristics can be obtained even if the electrode is configured as the common electrode 28.

FIG. 3 is a circuit configuration diagram of a plurality of pixel regions formed in a matrix that constitutes the liquid crystal display device according to the first embodiment. FIG. 2 is a plan configuration diagram in an arbitrary pixel region of the liquid crystal display device according to the first embodiment. FIG. 3 is a partial cross-sectional configuration diagram taken along line III-III in FIG. 2. Sectional drawing explaining 1st uneven | corrugated shape. FIG. 5 is a partial cross-sectional configuration diagram taken along line VV in FIG. 2. The figure which shows arrangement | positioning of each optical axis of the liquid crystal display device which concerns on 1st Embodiment. 3 is a graph showing a relationship between a cell gap difference and contrast of the liquid crystal display device according to the first embodiment. FIG. 6 is a schematic cross-sectional view showing a liquid crystal display device according to a second embodiment. FIG. 11 is a perspective view illustrating an example of an electronic apparatus according to the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display device 12 ... Pixel electrode (1st electrode) 14 ... TFT 16 ... Data line drive circuit 18 ... Data line 20 ... Scan line drive circuit 22a ... Scan line 22b ... Capacitance line 24 ... Storage capacitor 26 ... Opening 28 ... Common electrode (second electrode) 30 ... Reflective film 30a ... First uneven shape 32 ... Phase difference film 32a ... Slow axis 34 ... Semiconductor layer 36 ... Source electrode 38 ... Drain electrode 40 ... Contact hole 42 ... Black matrix layer 44 ... color filter layer 46 ... liquid crystal molecule 48 ... array substrate (first substrate) 48a ... substrate body 50 ... counter substrate (second substrate) 50a ... substrate body 52 ... liquid crystal layer 54 ... gate insulating film 56 ... first interlayer insulating film 58 ... Flattened layer 59 ... Underlayer 60 ... Second interlayer insulating film 62 ... Resin layer (third resin layer) 62a ... Second uneven shape 64 ... Water Alignment film (first resin layer) 66 ... Flattening layer 68 ... Horizontal alignment film (second resin layer) 70 ... First polarizing plate 70a ... Transmission axis 72 ... Second polarizing plate 72a ... Transmission axis 74 ... Liquid crystal alignment direction 78 ... Main direction of electric field 80 ... Frame 90 ... Liquid crystal display device 100 ... Mobile phone 102 ... Display unit 104 ... Operation button 106 ... Earpiece 108 ... Transmission port

Claims (5)

A liquid crystal layer is sandwiched between the first substrate and the second substrate, a first electrode on the liquid crystal layer side of the first substrate, and a second electrode for generating an electric field between the first electrode, A first polarizing plate and a second polarizing plate provided with a reflective display portion and a transmissive display portion in one pixel and having transmission axes substantially orthogonal to each other outside the first substrate and the second substrate. A transmission axis of one of the first polarizing plate and the second polarizing plate is set substantially parallel to the liquid crystal alignment direction of the liquid crystal layer,
The reflective display portion on the liquid crystal layer side of the first substrate is provided with a reflective film having a first concavo-convex shape on the surface on the liquid crystal layer side, and provided on the liquid crystal layer side of the reflective film. A first resin layer provided with the first concavo-convex shape on a surface in contact with the layer, and
The reflective display portion on the liquid crystal layer side of the second substrate is provided with a second resin layer having a second concavo-convex shape on the surface in contact with the liquid crystal layer,
The second concavo-convex convex portion is arranged in a plane corresponding to the second concavo-convex convex portion, and the first concave-convex concave portion is arranged in a plane corresponding to the first concave-convex convex portion, The liquid crystal display device characterized in that the first concavo-convex shape and the second concavo-convex shape are plane-symmetric concavo-convex shapes and are formed by inverting the concavo-convex shape. The liquid crystal display device according to claim 1.
A retardation film provided between the second substrate and the second resin layer in the reflective display unit;
A third resin layer provided between the retardation film and the second resin layer and having the second concavo-convex shape on the surface on the liquid crystal layer side;
The liquid crystal display device further comprising: The liquid crystal display device according to claim 1.
A color filter layer provided on the liquid crystal layer side of the second substrate;
A third resin layer provided between the color filter layer and the second resin layer in the reflective display portion, and having the second concavo-convex shape on the surface on the liquid crystal layer side;
Opposite the reflective film, provided between the third resin layer and the second resin layer, the first concavo-convex shape is provided on the surface opposite to the liquid crystal layer, and on the surface on the liquid crystal layer side A retardation film provided with the second uneven shape;
The liquid crystal display device further comprising: The liquid crystal display device according to claim 3.
A black matrix layer provided on the liquid crystal layer side of the second substrate;
A planarizing layer provided on the liquid crystal layer side of the second substrate to planarize a step between the color filter layer and the black matrix layer;
Further including
The liquid crystal display device, wherein the third resin layer is the planarization layer.   An electronic apparatus comprising the liquid crystal display device according to claim 1.

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