JP2006227661A - Liquid crystal device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection type liquid crystal device and a projection type display device, and electronic equipment which makes bright display with high contrast possible while preventing display defects caused by disclination in a high definition liquid display device with a narrow gap between pixels. <P>SOLUTION: The liquid crystal device which has a liquid crystal layer held between a 1st substrate and a 2nd substrate, and a 1st electrode and a 2nd electrode formed on the surface of the 2nd substrate on the side of the liquid crystal layer and is so constituted that the 1st electrode and 2nd electrode can apply an electric field to the liquid crystal layer substantially in parallel to substrate surfaces is characterized in that: the 1st electrode is formed in a line with a specified width on the 2nd electrode through a 2nd insulating filmto ; the 2nd electrode is formed in a rectangular shape; and at least one of the 1st electrode and 2nd electrode is a reflecting electrode reflect the light incident from the side of the 1st substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal device, and more particularly to a configuration of a liquid crystal device using a lateral electric field, and a projection display device and an electronic apparatus using the liquid crystal device.

  Conventionally, the demand for liquid crystal display devices is increasing not only as a direct-view type but also as a projection display element such as a projection television. When this liquid crystal display device is used as a projection type, if the enlargement ratio is increased with the conventional number of pixels, the roughness of the screen becomes conspicuous. Therefore, in order to obtain a fine image even at a high magnification, it is necessary to increase the number of pixels. However, when the number of pixels of the liquid crystal display device is increased, especially in an active matrix liquid crystal display device, the area occupied by portions other than the pixels, for example, a wiring portion and a thin film transistor (active element) portion becomes relatively large. Since the area of the black matrix that covers this portion increases, the area of the pixel opening that contributes to display decreases, and the aperture ratio as a display device decreases. When this aperture ratio decreases, the screen becomes dark, and the image quality as a liquid crystal display device decreases.

  Therefore, in order to prevent the aperture ratio from being lowered due to the increase in the number of pixels as much as possible, some projection display devices are being shifted from transmissive liquid crystal panels to reflective liquid crystal panels. By making the liquid crystal panel reflective, wiring portions such as scanning lines and signal lines can be formed below the reflective electrode, and the aperture ratio of the pixel can be improved.

  However, even if such various types of projection display devices appear, when a high-resolution liquid crystal panel is used, the distance between the pixels, that is, the distance between the pixel electrode and the pixel electrode is reduced. There has been a problem that liquid crystal disclination (tilt) occurs due to the influence of a lateral electric field received from the peripheral edge of another adjacent pixel electrode, and a defect occurs in the display area. This display area defect will be described in detail below.

  In a liquid crystal panel for a current projector having a high definition structure, the width of a rectangular pixel electrode is reduced to about 20 μm square, and a plurality of such pixel electrodes are arranged in a matrix in the display area. . In such a high-definition liquid crystal panel that employs a reflective structure, a structure in which the switching elements formed on the substrate are covered with an insulating film and the pixel electrodes are arranged without gaps. By adopting, the distance between pixel electrodes can be reduced to 1 μm or less.

  In such a high-definition liquid crystal panel having a structure in which the pixel electrode interval is narrowed, a strong lateral electric field acts on the liquid crystal present at the boundary between adjacent pixel electrodes. The liquid crystal that should be controlled between the common electrode and the pixel electrode originally formed on the inner surface of the counter substrate is likely to be oriented in different directions under the influence of the lateral electric field. That is, in the liquid crystal in the region whose orientation is to be controlled by the pixel electrode, a part of the liquid crystal is directed in a slightly different direction from the other liquid crystal, and the disclination line and the boundary region of the liquid crystal in which these alignment directions are slightly different There has been a problem of causing a linear display defect called. Further, when the width of the linear display defect was actually measured with this type of liquid crystal display device, it was found that the width was about 3 μm on average.

  Such a problem of display defects due to a lateral electric field is occurring not only in a projection display device but also in a high-definition direct-view liquid crystal device.

  For the purpose of eliminating such display defects, a liquid crystal device proposed in claims 50 to 65 of JP-A-11-202356 was examined. A conventional liquid crystal device controls a liquid crystal by a so-called vertical electric field generated by a pixel electrode and a common electrode respectively formed on a pair of substrate inner surfaces, whereas a horizontal electric field generated when a distance between the pixels is narrowed. This is an attempt to realize a liquid crystal device free from display defects by actively using it. However, the liquid crystal device proposed in Japanese Patent Application Laid-Open No. 11-202356 relates to a transmissive liquid crystal device, and each condition and configuration can be applied only to the transmissive liquid crystal device.

  The present invention has been made in view of the above-described problems, and prevents a display defect caused by disclination from occurring in a high-definition liquid crystal display device in which a pixel-to-pixel interval is narrow, and has high contrast. It is an object of the present invention to provide a liquid crystal device, a projection display device, and an electronic device that enable bright display.

  Means taken by the present invention to solve the above problems are as follows.

  The liquid crystal device according to claim 1, comprising: a liquid crystal layer sandwiched between a first substrate and a second substrate; and a first electrode and a second electrode formed on a surface of the second substrate on the liquid crystal layer side, In the liquid crystal device, wherein the first electrode and the second electrode can apply an electric field substantially parallel to the substrate surface to the liquid crystal layer, the first electrode is a second insulating film on the second electrode. The second electrode is formed in a rectangular shape, and at least one of the first electrode and the second electrode is incident from the first substrate side. It is a reflective electrode that reflects light.

  According to this means, it is possible to eliminate a display defect such as discnation caused by a horizontal electric field by adjacent pixels and to realize a bright and high-contrast reflective liquid crystal display. If the first electrode is a reflective electrode, light incident on the first electrode from the first substrate side can be reflected again to the first substrate side. In this case, the larger the line width of the first electrode, the more incident light can be reflected. Further, a large number of thin linear first electrodes may be formed. If the second electrode is a reflective electrode, light incident on the second electrode from the first substrate side can be reflected again to the first substrate side. In this case, the first electrode may be a transparent electrode such as ITO. Further, if both the first electrode and the second electrode are reflective electrodes, light incident on the pixel from the first substrate side can be reflected again to the first substrate side. In this case, if the first electrode is formed between adjacent pixels, the pixels can be effectively used for display.

  3. The liquid crystal device according to claim 2, wherein a liquid crystal layer sandwiched between the first substrate and the second substrate, a scanning signal line, an image signal line, and a first electrode formed on a surface of the second substrate on the liquid crystal layer side. A second electrode and an active element, wherein the first electrode and the second electrode are configured so that an electric field substantially parallel to a substrate surface can be applied to the liquid crystal layer. Is formed over the entire display area of the liquid crystal device through the first insulating film so as to cover the scanning signal line, the image signal line, and the active element, and has an opening, and the first electrode is A line having a predetermined line width is formed in each pixel via a second insulating film on the second electrode, and the first electrode and the active element are connected via an opening of the second electrode. At least one of the first electrode and the second electrode is the first electrode. Characterized in that it is a reflective electrode which reflects light incident from the plate side.

  According to this means, it is possible to eliminate a display defect such as discnation caused by a horizontal electric field by adjacent pixels and to realize a bright and high-contrast reflective liquid crystal display. Since the scanning signal line, the image signal line, and the active element can be disposed below the first electrode and the second electrode, a reflective liquid crystal with a high aperture ratio can be realized. If the first electrode is a reflective electrode, light incident on the first electrode from the first substrate side can be reflected again to the first substrate side. In this case, the larger the line width of the first electrode, the more incident light can be reflected. Further, a large number of thin linear first electrodes may be formed. If the second electrode is a reflective electrode, light incident on the second electrode from the first substrate side can be reflected again to the first substrate side. In this case, the first electrode may be a transparent electrode such as ITO. Since the second electrode is formed over the entire display area, it also serves as a light shielding film for the active element. In addition, since it is formed between adjacent pixels, a reflection type liquid crystal device having a very high aperture ratio can be realized.

  Further, if both the first electrode and the second electrode are reflective electrodes, light incident on the pixel from the first substrate side can be reflected again to the first substrate side. As the active element, a TFT (Thin Film Transistor) element, a MIM (Metal Insulator Metal) element, a TFD (Thin Film Diode) element, or the like can be used.

  The liquid crystal device according to claim 3 is characterized in that 4 <L1 / W1 ≦ 40, where W1 is a line width of the first electrode and L1 is an electrode interval.

  According to this means, since the electrode interval between the first electrodes is formed sufficiently wider than the line width of the first electrode, the area of the liquid crystal that is located on the first electrode and does not sufficiently respond to the electric field is minimized. Thus, a brighter and higher contrast reflective liquid crystal display can be realized.

  The liquid crystal device according to claim 4 is characterized in that 0.005 ≦ L1 / W1 <0.2, where W1 is a line width of the first electrode and L1 is an electrode interval.

  According to this means, since the electrode interval between the first electrodes is formed sufficiently narrower than the line width of the first electrode, most of the light incident from the first substrate side can be reflected by the first electrode. Thus, the phenomenon that incident light wraps around the active element portion can be suppressed as much as possible. This is to eliminate malfunction of the active element due to light leakage. Moreover, since it will become difficult to generate | occur | produce a horizontal electric field between a 1st electrode and a 2nd electrode if the electrode space | interval of a 1st electrode is made too narrow, the range of this invention is preferable.

  The liquid crystal device according to claim 5 is characterized in that 0.1 μm ≦ L1 <1 μm, where L1 is an interval between the first electrodes.

  According to this means, since the distance between the first electrodes is narrow, most of the light incident from the first substrate side can be reflected by the first electrode, and the incident light wraps around the active element portion. Can be suppressed as much as possible. This is to eliminate malfunction of the active element due to light leakage. Moreover, since it will become difficult to generate | occur | produce a horizontal electric field between a 1st electrode and a 2nd electrode if the electrode space | interval of a 1st electrode is made too narrow, the range of this invention is preferable.

  The liquid crystal device according to claim 6 is characterized in that 8 μm <L1 ≦ 25 μm, where L1 is an interval between the first electrodes.

  According to this means, since the gap between the first electrodes is sufficiently wide, the area of the liquid crystal that is located on the first electrode and does not sufficiently respond to the electric field can be reduced as much as possible. Type liquid crystal display can be realized.

  The liquid crystal device according to claim 7, wherein a plurality of openings in the second electrode exist in one pixel, and the plurality of linear first electrodes are connected to one same active element through each of the openings. .

  According to this means, a plurality of linear first electrodes can be connected from one active element in one pixel. As another method of forming a plurality of linear first electrodes in one pixel and connecting them to one active element, linear electrodes are provided in a direction perpendicular to the longitudinal direction of the linear first electrode, and each linear shape is provided. Although a method of short-circuiting the first electrode is conceivable, when this method is adopted, a lateral electric field generated between the first electrode and the second electrode is generated non-uniformly, and a bright and high-contrast reflective liquid crystal display is realized. You will not be able to. For this reason, the configuration of the present invention is very effective.

  The liquid crystal device according to claim 8 is characterized in that the first electrode also serves as a light shielding film.

  According to this means, the light incident on the active element portion among the light incident from the first substrate side can be reflected by the first electrode, and the phenomenon that the incident light wraps around the active element portion is suppressed as much as possible. Can do. This is to eliminate malfunction of the active element due to light leakage. Further, by using the light shielding film formed in the inter-pixel portion in the conventional liquid crystal device as the first electrode, it is possible to effectively use the pixels not contributing to the display for the reflective liquid crystal display. A high-contrast reflective liquid crystal display can be realized.

  The liquid crystal device according to claim 9 is characterized in that the second electrode also serves as a light shielding film.

  According to this means, among the light incident from the first substrate side, the light incident on the active element portion can be reflected by the second electrode, and the phenomenon that the incident light wraps around the active element portion is suppressed as much as possible. Can do. This is to eliminate malfunction of the active element due to light leakage. Further, by using the light shielding film formed in the inter-pixel portion in the conventional liquid crystal device as the second electrode, it is possible to effectively use the pixels that do not contribute to the display for the reflective liquid crystal display. A high-contrast reflective liquid crystal display can be realized.

  The liquid crystal device according to claim 10 is characterized in that the longitudinal direction of the linear first electrode is non-parallel and non-orthogonal on all four sides of the liquid crystal panel.

  According to this means, the liquid crystal can be aligned (initial alignment when no voltage is applied) in the longitudinal direction of the first substrate and the second substrate or in a direction orthogonal thereto. By doing so, polarized light having a transmission axis can be incident on the liquid crystal device in the longitudinal direction of the first substrate and the second substrate or in a direction orthogonal thereto. For example, the polarization beam splitter (PBS) used in the projection display device is limited in the polarization direction of the output polarized light because of its structure, so the liquid crystal device of the present invention is very convenient.

  The liquid crystal device according to claim 11 is characterized in that the shape of each pixel is a parallelogram and each corner is not a right angle.

  According to this means, the liquid crystal can be aligned (initial alignment when no voltage is applied) in the longitudinal direction of the first substrate and the second substrate or in a direction orthogonal thereto. By doing so, polarized light having a transmission axis can be incident on the liquid crystal device in the longitudinal direction of the first substrate and the second substrate or in a direction orthogonal thereto. For example, the polarization beam splitter (PBS) used in the projection display device is limited in the polarization direction of the output polarized light because of its structure, so the liquid crystal device of the present invention is very convenient.

  The liquid crystal device according to claim 12 is characterized in that 3 degrees ≦ β ≦ 87 degrees, where β is an angle formed by the longitudinal direction of the linear first electrode and the longitudinal direction of the liquid crystal panel.

  According to this means, the liquid crystal can be aligned (initial alignment when no voltage is applied) in the longitudinal direction of the first substrate and the second substrate or in a direction orthogonal thereto. By doing so, polarized light having a transmission axis can be incident on the liquid crystal device in the longitudinal direction of the first substrate and the second substrate or in a direction orthogonal thereto. For example, the polarization beam splitter (PBS) used in the projection display device is limited in the polarization direction of the output polarized light because of its structure, so the liquid crystal device of the present invention is very convenient. Note that 5 ° ≦ β ≦ 25 ° or 65 ° ≦ β ≦ 85 ° is a more preferable range.

  The liquid crystal device according to claim 13 is characterized in that, among adjacent pixels, the longitudinal direction of at least one linear first electrode is not parallel to the longitudinal direction of the linear first electrode of the adjacent pixel.

  According to this means, it is possible to realize a liquid crystal device with little change in viewing angle due to the liquid crystal. For example, when white display is performed on the entire screen of the liquid crystal device, the liquid crystal has almost the same orientation due to the transverse electric field in any part. When this substantially uniform liquid crystal alignment state is observed through a polarizing plate, viewing angle characteristics exist as in a conventional liquid crystal device. Therefore, when the longitudinal directions of the electrodes are made non-parallel between adjacent pixels as in the present invention, the alignment state (alignment direction) of the liquid crystal differs between the pixels, so that a liquid crystal device with little change in viewing angle can be realized. it can.

  The liquid crystal device according to claim 14 is characterized in that the shape of the linear first electrode is a letter “<”.

  According to this means, it is possible to realize a liquid crystal device with little change in viewing angle due to the liquid crystal. By making the electrode shape in one pixel “<”, there are two directions of the transverse electric field in one pixel, so that the alignment state of the liquid crystal can be two in one pixel, and the viewing angle A liquid crystal device with little change can be realized. In addition, the liquid crystal can be aligned (initial alignment when no voltage is applied) in the longitudinal direction of the first substrate and the second substrate or in a direction orthogonal thereto. By doing so, polarized light having a transmission axis can be incident on the liquid crystal device in the longitudinal direction of the first substrate and the second substrate or in a direction orthogonal thereto. For example, the polarization beam splitter (PBS) used in the projection display device is limited in the polarization direction of the output polarized light because of its structure, so the liquid crystal device of the present invention is very convenient.

  The liquid crystal device according to claim 15 is characterized in that the first insulating film has a flattening function so that the second electrode becomes a mirror surface.

  According to this means, the step due to the scanning signal line, the image signal line, and the active element arranged below the second electrode can be flattened, and the second electrode can be in a mirror state. As a result, incident light from the first substrate side can be efficiently reflected again to the first substrate side with a high reflectance. Further, a step due to the scanning signal line, the image signal line, and the active element adversely affects the liquid crystal. This can be suppressed.

  The liquid crystal device according to claim 16 is characterized in that the first electrode is a pixel electrode and the second electrode is a common electrode.

  According to this means, since the first electrode can be a pixel electrode and the second electrode can be a common electrode, a reflective liquid crystal display with a bright and high contrast can be realized by inputting a liquid crystal drive signal substantially the same as the conventional one. can do.

  The liquid crystal device according to claim 17 is characterized in that 0.01 μm ≦ D1 ≦ 5 μm, where D1 is a thickness of the first insulating film.

  According to this means, it is possible to prevent the scanning signal line, the image signal line, the active element, and the second electrode from being short-circuited. Further, a step caused by the scanning signal line, the image signal line, and the active element can be flattened. If the thickness of the first insulating film is 0.01 μm or more, the influence of the potential of the scanning signal line, the image signal line, and the active element on the second electrode (common electrode) can be almost ignored. 1 μm ≦ D1 ≦ 3 μm is a more preferable range.

  The liquid crystal device according to claim 18 is characterized in that 0.01 μm ≦ D2 ≦ 5 μm, where D2 is a thickness of the second insulating film.

  According to this means, it is possible to prevent the first electrode and the second electrode from being short-circuited. In addition, a lateral electric field generated between the first electrode and the second electrode can be efficiently applied to the liquid crystal layer. In addition, 0.1 μm ≦ D2 ≦ 2 μm is a more preferable range.

  The liquid crystal device according to claim 19 is characterized in that one of the first insulating film and the second insulating film is made of SiOx or SiNx.

  According to this means, the first insulating film and the second insulating film can be formed relatively easily and inexpensively. Further, high insulation can be realized. Since SiOx and SiNx have relatively high transmittance, they are preferably used as the first insulating film formed on the second electrode. By doing in this way, a high reflectance can be obtained with the second electrode.

  The liquid crystal device according to claim 20 is characterized in that a transmittance of the second insulating film in a visible light region is 80% or more.

  According to this means, a high reflectance can be realized with the second electrode. Of the light incident from the first substrate side, the light that reaches the second electrode passes through the second insulating film twice. When the transmittance of the second insulating film is less than 80%, approximately 40% to about half of the light is absorbed by the second insulating film, making it impossible to realize a bright reflective liquid crystal display.

  The liquid crystal device according to claim 21 is characterized in that the second insulating film is a color filter.

  According to this means, the light reflected by the second electrode is colored, and a reflective color display can be performed.

  The liquid crystal device according to claim 22 is characterized in that 0.1 μm ≦ Δn × d <0.2 μm, where d is the thickness of the liquid crystal layer and Δn is the refractive index anisotropy of the liquid crystal.

  According to this means, a bright and high contrast reflective liquid crystal display can be realized. Incident light from the first substrate side passes through the liquid crystal layer, is reflected by the first electrode or the second electrode, and passes through the liquid crystal layer again. That is, since it passes through the liquid crystal layer twice, the retardation represented by the product of the thickness of the liquid crystal layer and the refractive index anisotropy is about half that of the transmissive liquid crystal display device.

  24. The liquid crystal device according to claim 23, wherein an alignment film is formed on a surface of the first substrate and the second substrate in contact with the liquid crystal layer, and an angle (pretilt angle) between the liquid crystal molecules in the liquid crystal layer and the substrate surface is set. Assuming that θp, 10 degrees <θp ≦ 90 degrees.

  According to this means, it is possible to eliminate display defects due to unnecessary electric field components generated in the normal direction of the first substrate and the second substrate among the electric fields generated between the first electrode and the second electrode.

  25. The liquid crystal device according to claim 24, wherein an angle between an alignment axis of the alignment film formed on the inner surface of the first substrate and an alignment axis of the alignment film formed on the inner surface of the second substrate is 0 degree ≦ α <. It is characterized by 180 degrees.

  According to this means, the liquid crystal in the liquid crystal layer can be twisted (twisted) between the first substrate and the second substrate. By doing in this way, a liquid crystal can be controlled efficiently by the horizontal electric field produced between the 1st electrode and the 2nd electrode. In addition, by setting α to approximately 0 degrees, the tilt angle of the liquid crystal molecules located at the center of the liquid crystal layer with respect to the substrate surface can be approximately 0 degrees.

  The liquid crystal device according to claim 25 is characterized in that the liquid crystal layer includes a liquid crystal material having a negative dielectric anisotropy and having a cyano group.

  According to this means, since the liquid crystal material having negative dielectric anisotropy is used, the electric field generated between the first electrode and the second electrode is generated in the normal direction of the first substrate and the second substrate. Display defects due to unnecessary electric field components can be suppressed. In addition, since a liquid crystal material having a cyano group is included, the dielectric anisotropy is large, and the liquid crystal can be driven at a low voltage. As a result, a liquid crystal device with low power consumption can be realized.

  The liquid crystal device according to claim 26 is characterized in that the liquid crystal layer includes a chiral liquid crystal material.

  According to this means, the liquid crystal can be efficiently moved (driven) by a lateral electric field generated between the first electrode and the second electrode. In addition, high-speed response is possible. When chiral is mixed in a liquid crystal, the liquid crystal has an elastic energy level related to twist. Since the liquid crystal device of the present invention controls the liquid crystal to be twisted between the first substrate and the second substrate by a lateral electric field, it is very effective to initially give the liquid crystal material twist power. .

  The liquid crystal device according to claim 27, wherein the alignment film is made of SiOx.

  According to this means, uniform alignment of the liquid crystal can be obtained without rubbing (rubbing) the first substrate and the second substrate. Since it is rubbing free, there is no generation of static electricity or dust. The alignment film of SiOx can be realized by oblique oblique deposition in a vacuum. It is preferable to deposit SiOx at an angle of approximately 60 to 85 degrees from the normal direction of the substrate surface.

  The liquid crystal device according to claim 28, wherein the second substrate is a silicon (Si) substrate.

  According to this means, an active element having high mobility can be produced, and a reflective liquid crystal display with high speed and high contrast can be realized.

  The liquid crystal device according to claim 29 is characterized in that a transparent electrode having a constant potential is provided on a surface different from the liquid crystal layer of the first substrate.

  According to this means, a liquid crystal device in which the influence of static electricity is suppressed can be realized. Since the first substrate does not have electrodes on the surface in contact with the liquid crystal layer, it is vulnerable to static electricity. Therefore, the influence of static electricity can be suppressed by forming a transparent electrode having a constant potential on a surface different from the liquid crystal layer of the first substrate.

  The liquid crystal device according to claim 30 is characterized in that the transparent electrode has a zero potential.

  According to this means, since the existing potential can be used, it is possible to take a countermeasure against static electricity relatively easily.

  A liquid crystal device according to a thirty-first aspect is characterized in that the transparent electrode is made of ITO.

  According to this means, a countermeasure against static electricity can be taken without degrading the reflective liquid crystal display. ITO has high transmittance and is easy to manufacture.

  A liquid crystal device according to a thirty-second aspect is characterized in that a pixel pitch is 30 μm or less.

  According to this means, a bright and high-contrast reflective liquid crystal display can be realized with a high-definition liquid crystal device having a pixel pitch of 30 μm or less. The present invention is more effective for a liquid crystal device having a pixel pitch of 20 μm or less.

  The liquid crystal device according to claim 33 is characterized in that 5 ≦ L1 / D2 ≦ 30, where L1 is an electrode interval of the first electrodes and D2 is a thickness of the second insulating film.

  According to this means, a transverse electric field can be efficiently generated between the first electrode and the second electrode. Thereby, the liquid crystal can be driven with a low voltage.

  A projection display device according to a thirty-fourth aspect includes the liquid crystal device according to any one of the first to thirty-third aspects.

  According to this means, a bright and high-contrast projection display device can be realized.

  36. The projection display device according to claim 35, comprising: a light source; a light modulation device that modulates light from the light source; and a projection lens that projects light modulated by the light modulation device; A liquid crystal device according to any one of claims 1 to 33 is used.

  According to this means, a bright and high-contrast projection display device can be realized.

  The liquid crystal device according to claim 36, wherein a polarizing plate is disposed on a side of the first substrate different from the liquid crystal layer, the liquid crystal layer is uniaxially aligned, and the uniaxial alignment direction and the transmission axis of the polarizing plate are The liquid crystal layer has an angle of approximately 45 degrees and the phase difference of the liquid crystal layer is approximately ¼ wavelength.

  According to this means, it is possible to realize a direct-view reflective liquid crystal device that is bright and has high contrast.

  The liquid crystal device according to claim 37, wherein at least one retardation plate and a polarizing plate are sequentially arranged on a side of the first substrate different from the liquid crystal layer, and the liquid crystal layer and the retardation plate are combined. Is approximately ¼ wavelength with respect to light in the visible light range.

  According to this means, it is possible to realize a direct-view reflective liquid crystal device that is bright and has high contrast.

  The liquid crystal device according to claim 38, wherein at least one retardation plate and a polarizing plate are sequentially disposed on a side of the first substrate different from the liquid crystal layer, and the retardation plate is approximately ¼ in a visible light region. It is characterized by a wavelength.

  According to this means, it is possible to realize a direct-view reflective liquid crystal device that is bright and has high contrast.

  The liquid crystal device according to claim 39 is characterized in that a color filter corresponding to each pixel is formed on a surface of the first substrate on the liquid crystal layer side.

  According to this means, it is possible to realize a direct-view type reflective color liquid crystal device that is bright and has high contrast.

  An electronic apparatus according to a 40th aspect is characterized by mounting the liquid crystal device according to any one of the 36th to 39th aspects.

  According to this means, it is possible to realize an electronic device with high visibility equipped with a direct-view type reflective color liquid crystal device that is bright and has high contrast.

  A reflection type liquid crystal device and a projection type display device capable of preventing a display defect due to disclination and enabling a high-contrast and bright display to a high-definition liquid crystal display device in which the distance between pixels is narrow And electronic equipment can be realized.

  Next, embodiments according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing the structure of a first embodiment of a liquid crystal device according to the present invention. FIG. 1A is a front view of one pixel, and FIG. The liquid crystal layer 103 is sandwiched between the two substrates 101 and 102. An alignment film 104 is formed on the inner surface of the upper substrate 101. The lower substrate 102 has a second electrode 107, an insulating film 108 made of SiOx, a first electrode 106, and an alignment film 105 formed therein.

  The first electrode 106 is a linear transparent electrode, and the second electrode 107 is a rectangular reflective electrode. The second electrode 107 has a function of reflecting light 109 incident from the upper substrate 101 side. The liquid crystal 103 is controlled by an external drive circuit with an electric field generated by a potential difference between the first electrode 106 and the second electrode 107. Since this reflective liquid crystal device actively generates a horizontal electric field that has been a cause of display defects in the past and controls the liquid crystal, the horizontal electric field is the same as when a vertical electric field is applied between the conventional upper and lower substrates. There is no display defect such as discnation caused by it. For this reason, a bright and high contrast reflective liquid crystal display could be realized.

  In the present embodiment, the second electrode 107 is a reflective electrode and the first electrode 106 is a transparent electrode made of ITO. However, the first electrode 106 may also be a reflective electrode. The reflective electrode is mainly composed of Al (aluminum), Ag (silver), Cr (chromium), Ta (tantalum), Ni (nickel), Au (gold), Cu (copper), Pt (platinum), and the like. Alloys can be used. By using these metal alloys, a reflective liquid crystal device with high reflectivity can be realized.

  In this embodiment, SiOx is used for the insulating film 108, but a transparent resin such as SiNx or acrylic may be used. These materials can realize high insulation.

  A material having a transmittance of 80% or more is preferably used for the insulating film 108 of this embodiment. SiOx, SiNx, and acrylic resin are excellent materials in this respect. Further, when the insulating film 108 is a color filter, the light reflected by the second electrode is colored, and a reflective color display can be performed. In order to perform full color display, it is preferable to form red (R), green (G), and blue (B) color filters corresponding to each pixel.

  In this embodiment, a nematic liquid crystal material exhibiting negative dielectric anisotropy is used. As a result, display defects due to unnecessary vertical electric field components generated in the normal direction of the upper substrate 101 and the lower substrate 102 in the electric field generated between the first electrode 106 and the second electrode 107 can be eliminated. In addition, since a liquid crystal material containing a liquid crystal having a cyano group was used, the dielectric anisotropy was large, and the liquid crystal could be controlled at a low voltage. As a result, a liquid crystal device with low power consumption can be realized. Furthermore, high-speed response is possible by mixing chiral into the liquid crystal material.

  In this embodiment, the alignment films 104 and 105 are rubbed with a polyimide organic film, but an alignment film obtained by obliquely depositing SiOx in vacuum may be used.

  By doing so, there was no generation of static electricity and dust, and the manufacturing yield was dramatically improved.

  As shown in FIG. 1, when the line width of the first electrode 106 is W1 and the interval between the first electrodes 106 is L1, when there are a plurality of W1 and L1 in one pixel, W1 and L1 are all in one pixel. It doesn't have to be the same.

  FIG. 2 is a schematic view showing the structure of the second embodiment of the liquid crystal device according to the present invention. 2A is a front view of one pixel, and FIG. 2B is a cross-sectional view. A structure in which a liquid crystal layer 203 is sandwiched between two substrates 201 and 202 is employed. The upper substrate 201 has an alignment film 204 formed on the inner surface. On the lower substrate 202, scanning signal lines, image signal lines, and TFT elements 210 are formed on the inner side, and a first insulating film 209, a common electrode 207, a second insulating film 208, a pixel electrode 206, and an alignment film 205 are further formed thereon. Are sequentially formed. An opening (contact hole) 212 is provided in the common electrode 207, and the TFT element 210 and the pixel electrode 206 are in contact with each other. The pixel electrode 206 is a linear transparent electrode, and the common electrode 207 is a reflective electrode formed substantially over the entire display area of the liquid crystal panel (formed across adjacent pixels). The common electrode 207 has a function of reflecting the light 211 incident from the upper substrate 201 side. The liquid crystal 203 is controlled by an external drive circuit with an electric field generated by a potential difference between the pixel electrode 206 and the common electrode 207. Since this reflective liquid crystal device actively generates a horizontal electric field that has been a cause of display defects in the past and controls the liquid crystal, the horizontal electric field is the same as when a vertical electric field is applied between the conventional upper and lower substrates. There is no display defect such as discnation caused by it. For this reason, a bright and high contrast reflective liquid crystal display could be realized.

  In this embodiment, the common electrode 207 is a reflective electrode and the pixel electrode 206 is a transparent electrode made of ITO. However, the pixel electrode 206 may also be a reflective electrode. Since the common electrode 207 is generally formed over the entire display area, it also serves as a light shielding film for the TFT element 210. As a result, malfunction of the TFT element 210 due to light leakage could be eliminated. In addition, by using the common electrode 207 as a light-shielding film formed in an inter-pixel portion in a conventional liquid crystal device, pixels that do not contribute to display can be effectively used for reflective liquid crystal display. A high-contrast reflective liquid crystal display could be realized.

  By forming the first insulating film 209 with a predetermined thickness, the steps due to the scanning signal lines, the image signal lines, and the TFT elements 210 disposed below the common electrode 207 can be flattened. Could be mirrored. As a result, incident light from the upper substrate 201 side can be efficiently reflected again to the upper substrate 201 side with a high reflectance. In addition, the step due to the scanning signal line, the image signal line, and the TFT element 210 often adversely affects the alignment of the liquid crystal 203. However, since the first insulating film 209 has a function of a planarization film, this can be suppressed. did it.

  In the present embodiment, a silicon (Si) substrate is used for the lower substrate 202. As a result, the TFT element 210 having a high mobility can be produced, and a high-speed and high-contrast reflective liquid crystal display can be realized.

  In the reflective liquid crystal device of FIG. 2, the electrode width of the pixel electrode 206 is defined as W1, and the interval between the pixel electrodes 206 is defined as L1. Here, the relationship between the ratio (L1 / W1) of the interval L1 of the pixel electrode 206 to the electrode width W1 of the pixel electrode 206 and the reflectance of the reflective liquid crystal device was examined. The upper part of Table 1 is a case where the pixel electrode 206 is a reflective electrode, and the lower part is a case where the common electrode 207 is a reflective electrode.

表１の上段によると、Ｌ１／Ｗ１が０．００５以上０．２未満のとき、６０％以上の反射率の液晶装置を実現することができる。画素電極２０６の電極間隔Ｌ１を画素電極２０６の線幅Ｗ１よりも十分に狭く形成しているので、上基板２０１側から入射した光のほとんどを画素電極２０６で反射させることができ、ＴＦＴ素子部２１０に入射光が回り込む現象を抑えることができた。画素電極２０６の電極間隔Ｌ１を画素電極２０６の線幅Ｗ１よりも狭くしすぎると、画素電極２０６と共通電極２０７の間で横電界を発生しにくくなってしまうので、Ｌ１／Ｗ１が０．００５未満では反射型液晶装置の反射率が低下することがわかった。また、Ｌ１／Ｗ１をある程度大きくすると、隣の画素の電位によって画素電極２０６と共通電極２０７間に生じる横電界が乱されるので、０．２以上では反射型液晶装置の反射率が低下することがわかった。

According to the upper part of Table 1, when L1 / W1 is 0.005 or more and less than 0.2, a liquid crystal device having a reflectance of 60% or more can be realized. Since the electrode interval L1 of the pixel electrode 206 is formed sufficiently narrower than the line width W1 of the pixel electrode 206, most of the light incident from the upper substrate 201 side can be reflected by the pixel electrode 206, and the TFT element portion It was possible to suppress the phenomenon in which incident light circulates to 210. If the electrode interval L1 of the pixel electrode 206 is too narrower than the line width W1 of the pixel electrode 206, it becomes difficult to generate a horizontal electric field between the pixel electrode 206 and the common electrode 207, so L1 / W1 is 0.005. It has been found that the reflectance of the reflective liquid crystal device is lowered when the ratio is less than 1. Further, if L1 / W1 is increased to some extent, the horizontal electric field generated between the pixel electrode 206 and the common electrode 207 is disturbed by the potential of the adjacent pixel, so that the reflectance of the reflective liquid crystal device decreases at 0.2 or more. I understood.

  The electrode interval L1 between the pixel electrodes 206 is preferably 0.1 μm or more and less than 1 μm. Since the electrode interval L1 of the pixel electrode 206 is narrow, most of the light incident from the upper substrate 201 side can be reflected by the pixel electrode 206, and the phenomenon that the incident light wraps around the TFT element portion 210 is as much as possible. I was able to suppress it. In addition, if the electrode interval L1 between the pixel electrodes 206 is too small, it is difficult to generate a horizontal electric field between the pixel electrode 206 and the common electrode 207, and therefore a range of 0.1 μm or more and less than 1 μm is preferable.

  According to the lower part of Table 1, when L1 / W1 is larger than 4 and 40 or less, a liquid crystal device having a reflectance of 60% or more can be realized. Since the electrode interval L1 of the pixel electrode 206 is formed sufficiently wider than the line width W1 of the pixel electrode 206, most of the light incident from the upper substrate 201 side can be reflected by the common electrode 207, and the TFT element portion It was possible to suppress the phenomenon in which incident light circulates to 210. If the electrode interval L1 of the pixel electrode 206 is narrower than four times the line width W1 of the pixel electrode 206, the influence of the non-uniform electric field generated at the edge portion of the pixel electrode 206 is increased and the liquid crystal alignment is disturbed. It has been found that the reflectance of the reflective liquid crystal device is lowered when the ratio is less than 1. In addition, when L1 / W1 is increased to some extent, the lateral electric field generated between the pixel electrode 206 and the common electrode 207 is disturbed by the potential of the adjacent pixel, so that the reflectivity of the reflective liquid crystal device is decreased at 40 or more. It was.

  In the reflective liquid crystal device of FIG. 2, the reflectance of the reflective liquid crystal device was examined by changing the line width W1 of the pixel electrode 206 to 1 μm and changing the electrode interval L1 of the pixel electrode 206. At this time, the pixel electrode 206 is a transparent electrode, and the common electrode 207 is a reflective electrode.

表２によると、８μｍより大きく２５μｍ以下のＬ１であれば、６０％以上の反射率を実現する反射型液晶装置をつくることができた。Ｌ１が８μｍ以下では画素電極２０６のエッジ部分で生じる不均一電界の影響が大きくなり液晶配向を乱すので、反射型液晶装置の反射率が低下することがわかった。逆に、Ｌ１が２５μｍより大きくなると、隣の画素の電位によって画素電極２０６と共通電極２０７間に生じる横電界が乱されるので、反射型液晶装置の反射率が低下することがわかった。

According to Table 2, when L1 is larger than 8 μm and not larger than 25 μm, a reflection type liquid crystal device realizing a reflectance of 60% or more could be produced. It was found that when L1 is 8 μm or less, the influence of the non-uniform electric field generated at the edge portion of the pixel electrode 206 is increased and the liquid crystal alignment is disturbed, so that the reflectance of the reflective liquid crystal device is lowered. Conversely, it was found that when L1 is greater than 25 μm, the lateral electric field generated between the pixel electrode 206 and the common electrode 207 is disturbed by the potential of the adjacent pixel, so that the reflectance of the reflective liquid crystal device decreases.

  Further, it is preferable that the interval between the pixels is smaller than the electrode interval L1 between the pixel electrodes. By doing so, the horizontal electric field generated between the pixel electrode and the common electrode by the adjacent pixel potential is less likely to be disturbed.

  FIG. 3 is a schematic view showing the structure of the fourth embodiment of the liquid crystal device according to the present invention. 3A is a front view of one pixel, and FIG. 3B is a cross-sectional view. A structure in which a liquid crystal layer 303 is sandwiched between two substrates 301 and 302 is employed. An alignment film 304 is formed on the inner surface of the upper substrate 301. On the lower substrate 302, scanning signal lines, image signal lines, and TFT elements 312 are formed on the inner side, and a first insulating film 309, a common electrode 307, a second insulating film 308, a pixel electrode 306, and an alignment film 305 are further formed thereon. Are sequentially formed. The common electrode 307 has three openings (contact holes) 310, and the TFT element 312 and the pixel electrode 306 are in contact with each other through the openings 310. The pixel electrode 306 is a rectangular reflective electrode having a width W1, and the common electrode 307 is a reflective electrode formed substantially at a portion between the pixel electrodes 306, that is, a lower layer of the pixel electrode interval L1. The pixel electrode 306 and the common electrode 307 have a function of reflecting light 311 incident from the upper substrate 301 side. The liquid crystal 303 is controlled by an external drive circuit with an electric field generated by a potential difference between the pixel electrode 306 and the common electrode 307. Since this reflective liquid crystal device actively generates a horizontal electric field that has been a cause of display defects in the past and controls the liquid crystal, the horizontal electric field is the same as when a vertical electric field is applied between the conventional upper and lower substrates. There is no display defect such as discnation caused by it. For this reason, a bright and high contrast reflective liquid crystal display could be realized.

  In this embodiment, the pixel electrode 306 is formed so as to also serve as a light shielding film of the TFT element 312. As a result, the malfunction of the TFT element 312 due to light leakage could be eliminated.

  In this embodiment, the ITO transparent electrode 313 having the ground potential is provided on a surface different from the upper substrate 301 and the liquid crystal layer 303. This realized a liquid crystal device that was not affected by static electricity.

  In the liquid crystal device having the same configuration as that of the first to fourth embodiments, the shape of the pixel is a parallelogram whose corners are not perpendicular as shown in FIG. A pixel electrode 401 is formed on the common electrode 402 via an insulating film, and the pixel electrode 401 is connected to a lower TFT element at a contact portion 403. One area 409 defined by a dotted line in FIG. 4A represents one pixel (the pitch of this one pixel is P). The longitudinal direction 404 of the linear pixel electrode 401 is neither parallel nor orthogonal to the minor axis direction 407 and major axis direction 406 of the liquid crystal panel 405 shown in FIG. In this manner, the liquid crystal can be initially aligned in the short axis direction 407 or the long axis direction 406 of the liquid crystal panel 405 (alignment when no electric field is applied). In order to incline the liquid crystal with respect to the direction of the horizontal electric field generated between the pixel electrode 401 and the common electrode 402, the liquid crystal is not initially aligned parallel or perpendicular to the longitudinal direction 404 of the pixel electrode 401, but in the longitudinal direction 404. On the other hand, the initial orientation must be performed with a predetermined angle.

  This is because the liquid crystal is uniformly controlled with respect to the lateral electric field. Polarized light having a transmission axis in the minor axis direction 407 or the major axis direction 406 of the liquid crystal panel 405 can be incident on the reflective liquid crystal device. For example, the polarization beam splitter (PBS) used in the projection display device is limited in the polarization direction of the output polarized light due to its structure, and is usually the short axis direction 407 or the long axis direction 406 of the liquid crystal panel 405. The liquid crystal device of the present invention is very convenient. A symbol 408 in FIG. 4B represents a connector tape for inputting a signal to the liquid crystal panel.

  Further, if the angle formed by the longitudinal direction of the linear pixel electrode and the long axis direction of the liquid crystal panel is β, it is preferable that 3 ° ≦ β ≦ 87 °. This is because the liquid crystal can be initially aligned in the short axis direction 407 or the long axis direction 406 of the liquid crystal panel 405 as described above. Note that 5 ° ≦ β ≦ 25 ° or 65 ° ≦ β ≦ 85 ° is a more preferable range. By setting this range, the liquid crystal can be controlled with a lower voltage.

  In the liquid crystal device having the same configuration as that of the first to fourth embodiments, the shape of the pixel is a parallelogram whose corners are not right as shown in FIG. It was formed so as not to be parallel to the longitudinal direction of the adjacent pixel electrode 501. A pixel electrode 501 is formed on the common electrode 502 via an insulating film, and the pixel electrode 501 is connected to a lower TFT element at a contact portion 503. One area 506 divided by a dotted line in FIG. 5 represents one pixel. Since the longitudinal directions 504 and 505 of the pixel electrode 501 in FIG. 5 are not parallel to each other, the alignment state at the time of applying an electric field is different between the two pixels, and a liquid crystal device with little change in viewing angle can be realized. For example, when white display is performed on the entire screen of the liquid crystal device, the liquid crystal has almost the same orientation due to the transverse electric field in any part. When this substantially uniform liquid crystal alignment state is observed through a polarizing plate, viewing angle characteristics exist as in a conventional liquid crystal device. Therefore, when the longitudinal directions of the electrodes are made non-parallel between adjacent pixels as in the present invention, the alignment state (alignment direction) of the liquid crystal differs between the pixels, so that a liquid crystal device with little change in viewing angle can be realized. it can.

  In addition, even when the shape of the pixel electrode 601 in one pixel as shown in FIG. 6 is formed in a “<” shape, a liquid crystal device with little change in viewing angle due to the liquid crystal can be realized.

  A “<”-shaped pixel electrode 601 is formed on the common electrode 602 via an insulating film, and the pixel electrode 601 is connected to a lower TFT element at a contact portion 603.

  One area 604 divided by a dotted line in FIG. 6 represents one pixel. By making the shape of the pixel electrode 601 in one pixel “<”, there are two directions of the horizontal electric field in one pixel, so that the alignment state of the liquid crystal can be two in one pixel. Thus, a liquid crystal device with little change in viewing angle can be realized.

  In the reflective liquid crystal device shown in FIG. 2, the thickness D1 of the first insulating film 209 is preferably 0.01 μm ≦ D1 ≦ 5 μm. By selecting D1 in this range, it is possible to prevent the scanning signal line, the image signal line, the TFT element 210, and the common electrode 207 from being short-circuited. In addition, steps generated by the scanning signal lines, the image signal lines, and the TFT elements 210 can be flattened. If the thickness D1 of the first insulating film 209 is 0.01 μm or more, the influence of the potential of the scanning signal line, the image signal line, and the TFT element 210 on the common electrode 207 can be almost ignored. On the other hand, when D1 exceeds 5 μm, it becomes too thick and it becomes difficult to ensure flatness. 1 μm ≦ D1 ≦ 3 μm is a more preferable range.

  Next, in the reflective liquid crystal device shown in FIG. 2, the thickness D2 of the second insulating film 208 was changed, and the reflectance of the liquid crystal device was examined. The results are summarized in Table 3.

第２絶縁膜２０８の厚さＤ２が０．０１μｍ≦Ｄ２≦５μｍであれば、反射率６０％以上を確保することができる。また、この範囲であれば、画素電極２０６と共通電極２０７がショートすることを防止することができる。また、画素電極２０６と共通電極２０７間で生じる横電界を効率よく、液晶層２０３に印加することができる。さらに、０．１μｍ≦Ｄ２≦２μｍの範囲であれば、反射率８０％以上の反射型液晶装置を実現することができる。

If the thickness D2 of the second insulating film 208 is 0.01 μm ≦ D2 ≦ 5 μm, a reflectance of 60% or more can be ensured. In addition, within this range, the pixel electrode 206 and the common electrode 207 can be prevented from being short-circuited. In addition, a lateral electric field generated between the pixel electrode 206 and the common electrode 207 can be efficiently applied to the liquid crystal layer 203. Furthermore, when the range is 0.1 μm ≦ D2 ≦ 2 μm, a reflective liquid crystal device having a reflectance of 80% or more can be realized.

  Further, the distance between adjacent pixels is preferably 3 times or less the thickness D2 of the second insulating film 208. More preferably, it should be 2 times or less. By doing so, it is possible to realize a reflective liquid crystal device that is less affected by the potential of adjacent pixel electrodes.

  The relationship between the thickness d of the liquid crystal layer 103 and the refractive index anisotropy Δn of the liquid crystal Δn × d in the reflective liquid crystal device of FIG. 1 and the reflectance of the liquid crystal device was examined. Δn × d was changed from 0.05 to 0.41. The results are summarized in Table 4.

表４から明らかなように、液晶層１０３の厚さｄと液晶の屈折率異方性Δｎの積Δｎ×ｄが、０．１以上０．２未満の時、反射率が６０％以上の反射型液晶装置が実現できた。

As is apparent from Table 4, when the product Δn × d of the thickness d of the liquid crystal layer 103 and the refractive index anisotropy Δn of the liquid crystal is 0.1 or more and less than 0.2, the reflectance is 60% or more. Type liquid crystal device was realized.

  In the reflective liquid crystal device shown in FIG. 1, it is desirable that 10 ° <θp ≦ 90 °, where θp is an angle (pretilt angle) between the liquid crystal molecules in the liquid crystal layer 103 and the substrate surface. When the pretilt angle θp is within this range, display defects due to unnecessary vertical electric field components generated in the normal direction of the upper substrate 101 and the lower substrate 102 out of the electric field generated between the first electrode 106 and the second electrode 107 are eliminated. be able to. This is because even if a vertical electric field occurs, the orientation is not disturbed because it is inclined in advance in one direction by the pretilt angle θp.

  FIG. 7 is a schematic view of a liquid crystal panel having the pixel configuration of FIG. The arrow 701 in FIG. 7 is the alignment direction of the liquid crystal on the upper substrate, and the arrow 702 is the alignment direction of the liquid crystal on the lower substrate. The angle formed by the alignment directions of the upper and lower substrates is defined as α. α is preferably in the range of 0 ° to less than 180 °. When α is set in this way, the liquid crystal in the liquid crystal layer can be twisted (twisted) between the upper substrate and the lower substrate. Accordingly, the liquid crystal can be efficiently controlled by a lateral electric field generated between the first electrode and the second electrode. In addition, by setting α to approximately 0 °, it is possible to realize a splay alignment in which the tilt angle of the liquid crystal molecules located at the center of the liquid crystal layer with respect to the substrate surface is approximately 0 °.

  In a conventional TN (twisted nematic) type liquid crystal device, the area of the disclination display defect due to the pixel pitch P and the lateral electric field and the effective aperture ratio in the pixel area excluding the display defect portion were examined. The results are summarized in Table 5.

表５に示す結果から、ディスクリネーションラインが生成した場合に表示領域においてディスクリネーションラインから表示が影響を受けない有効面積の割合として示される有効開口率は、画素ピッチが３０μｍ以下となると８５％を割るようになるので、画素ピッチ３０μｍ以下の範囲の中でもより小さな画素ピッチの場合に有効であると思われる。具体的に、画素ピッチが２０μｍでは有効開口率８０％以下、画素ピッチ１０μｍ以下では有効開口率６０％以下となってしまう。このように、３０μｍ以下の画素ピッチを有する液晶装置には、本発明のような横電界の液晶モードを用いるのが良いことがわかった。本発明の液晶装置は、画素ピッチＰが３０μｍ以下になっても、有効開口率が低下することがないので、明るい反射型表示が実現できる。

From the results shown in Table 5, when the disclination line is generated, the effective aperture ratio shown as the ratio of the effective area where the display is not affected by the disclination line in the display area is 85 when the pixel pitch is 30 μm or less. % Is considered to be effective in the case of a smaller pixel pitch within the range of the pixel pitch of 30 μm or less. Specifically, when the pixel pitch is 20 μm, the effective aperture ratio is 80% or less, and when the pixel pitch is 10 μm or less, the effective aperture ratio is 60% or less. Thus, it was found that the liquid crystal mode having a pixel pitch of 30 μm or less should preferably use the liquid crystal mode of the lateral electric field as in the present invention. The liquid crystal device of the present invention can realize a bright reflective display because the effective aperture ratio does not decrease even when the pixel pitch P is 30 μm or less.

  In the reflective liquid crystal device of FIG. 2, the interval between the pixel electrodes 206 is defined as L1, and the thickness of the second insulating film is defined as D2. Here, the relationship between the ratio (L1 / D2) of the thickness D2 of the second insulating film to the distance L1 between the pixel electrodes 206 and the reflectance and contrast ratio of the reflective liquid crystal device was examined. The experiment was performed with the line width W1 of the pixel electrode 206 being constant at 1 μm and the interval L1 between the pixel electrodes 206 being constant at 4 μm. The reflectance is the brightness when 5 V is applied between the pixel electrode 206 and the common electrode 207, and the contrast ratio is the ratio of the brightness (reflectance) when no voltage is applied and when 5 V is applied.

表６によると、Ｌ１／Ｄ２が５以上３０以下のとき、８０％以上の反射率の液晶装置を実現することができる。また、４００以上のコントラスト比を得ることができる。以上から、５≦Ｌ１／Ｄ２≦３０とすることによって、明るくコントラストの高い反射表示を実現できる。

According to Table 6, when L1 / D2 is 5 or more and 30 or less, a liquid crystal device having a reflectance of 80% or more can be realized. In addition, a contrast ratio of 400 or more can be obtained. From the above, by setting 5 ≦ L1 / D2 ≦ 30, it is possible to realize a bright and high-contrast reflective display.

  FIG. 8 illustrates a configuration of a projection display device (liquid crystal projector) as an application example using the liquid crystal device of the present embodiment. FIG. 8 is a cross-sectional view of the liquid crystal projector in the XY plane passing through the center of the optical element 850.

The liquid crystal projector of the present embodiment includes a polarized light illumination device 800 that is roughly configured by a light source unit 810, an integrator lens 820, and a polarization conversion element 830 arranged along the system optical axis L, and S-polarized light emitted from the polarized light illumination device 800. A polarizing beam splitter 840 that reflects the light beam by the S-polarized light beam reflecting surface 841, and a dichroic mirror 842 that separates the blue light (B) component from the light reflected from the S-polarized light beam reflecting surface 841 of the polarizing beam splitter 840; A reflective liquid crystal light valve 845B that modulates the separated blue light (B), and a dichroic mirror 843 that reflects and separates the red light (R) component of the luminous flux after the blue light is separated. Reflective liquid crystal light valve 845R that modulates red light (R) and the remainder that passes through dichroic mirror 843 Reflective liquid crystal light valve 845G that modulates green light (G) of light, light modulated by three reflective liquid crystal light valves 845R, 845G, and 845B is synthesized by dichroic mirrors 843 and 842 and polarization beam splitter 840. The projection optical system 850 includes a projection lens that projects the combined light onto the screen 860. Each of the three reflective liquid crystal light valves 845R, 845G, and 845B uses the liquid crystal display device (liquid crystal panel) described in the above embodiment.

  The randomly polarized light beam emitted from the light source unit 810 is divided into a plurality of intermediate light beams by the integrator lens 820, and then the polarized light beam is substantially aligned by the polarization conversion element 820 having the second integrator lens on the light incident side. After being converted into a kind of polarized light beam (S-polarized light beam), it reaches the polarization beam splitter 840. The S-polarized light beam emitted from the polarization conversion element 830 is reflected by the S-polarized light beam reflecting surface 841 of the polarization beam splitter 840, and among the reflected light beams, the blue light (B) light beam is the blue light of the dichroic mirror 842. Reflected by the reflective layer and modulated by the reflective liquid crystal light valve 845B. Of the light beams transmitted through the blue light reflecting layer of the dichroic mirror 842, the red light (R) light beam is reflected by the red light reflecting layer of the dichroic mirror 843 and modulated by the reflective liquid crystal light valve 845R. . On the other hand, the luminous flux of green light (G) transmitted through the red light reflection layer of the dichroic mirror 843 is modulated by the reflective liquid crystal light valve 845G.

  As described above, the color light is modulated by the reflective liquid crystal light valves 845R, 845G, and 845B.

  Of the color light reflected from the pixels of the liquid crystal panel, the S-polarized component does not pass through the polarization beam splitter 840 that reflects the S-polarized light, and the P-polarized component passes therethrough. An image is formed by the light transmitted through the polarization beam splitter 840.

  The reflective liquid crystal panel uses a semiconductor technology to form pixels compared to an active matrix liquid crystal panel in which a TFT array is formed on a glass substrate. Therefore, the number of pixels can be increased and the panel size can be reduced. It can project fine images and contribute to miniaturization of the projector itself. In addition, since the reflective liquid crystal panel of the present invention has a high reflectivity because a display defect due to a horizontal electric field hardly occurs even when the resolution is increased, a bright projection display can be obtained.

  FIG. 9 is a schematic sectional view showing the structure of the twelfth embodiment of the liquid crystal device according to the present invention. A structure in which a liquid crystal layer 903 is sandwiched between two substrates 901 and 902 is employed.

  A color filter 907 and an alignment film 908 are sequentially formed on the inner surface of the upper substrate 901. Two retardation plates 906 and 905 and a polarizing plate 904 are sequentially formed on the outer surface of the upper substrate 901. In the lower substrate 902, a second electrode 912, an insulating film 910 made of SiOx, a first electrode 911, and an alignment film 909 are formed inside. The first electrode 911 is a linear transparent electrode, and the second electrode 912 is a rectangular reflective electrode. The second electrode 912 has a function of reflecting light incident from the upper substrate 901 side. The liquid crystal 903 is controlled by an external driving circuit with an electric field generated by a potential difference between the first electrode 911 and the second electrode 912. Since this reflective liquid crystal device actively generates a horizontal electric field that has been a cause of display defects in the past and controls the liquid crystal, the horizontal electric field is the same as when a vertical electric field is applied between the conventional upper and lower substrates. There is no display defect such as discnation caused by it. For this reason, it was possible to realize a bright and high-contrast reflective color liquid crystal display.

  Next, a specific example of an electronic apparatus provided with the reflective color liquid crystal display device will be described.

  FIG. 10A is a perspective view showing an example of a mobile phone.

  FIG. 10B is a perspective view illustrating an example of a wristwatch type electronic device.

  FIG. 10C is a perspective view showing an example of a portable information processing apparatus such as a word processor or a personal computer.

  Each of the electronic devices shown in FIGS. 10A to 10C includes the reflective color liquid crystal display device described above, and has the characteristics of any of the liquid crystal display devices of the above-described embodiments. Regardless of which liquid crystal display device is used, a high-definition display with a high contrast ratio can be obtained.

It is the schematic which shows the structure of Example 1 of the liquid crystal device which concerns on this invention. It is the schematic which shows the structure of Example 2 of the liquid crystal device which concerns on this invention. It is the schematic which shows the structure of Example 4 of the liquid crystal device which concerns on this invention. It is a figure showing the shape of a pixel and a liquid crystal panel concerning the present invention. It is a figure showing the shape of the pixel which concerns on this invention. It is a figure showing the shape of the pixel which concerns on this invention. It is the schematic of the liquid crystal panel which showed the orientation direction of the liquid crystal. It is a figure showing the structure of the projection type display apparatus (liquid crystal projector) as an application example using the liquid crystal device which concerns on this invention. It is a schematic sectional drawing which shows the structure of Example 13 of the liquid crystal device based on this invention. It is the schematic of the electronic device carrying the liquid crystal device which concerns on this invention.

Explanation of symbols

101, 201, 301, 901 Upper substrate 102, 202, 302, 902 Lower substrate 103, 203, 303, 903 Liquid crystal layer 104, 105, 204, 205, 304, 305, 908, 909 Alignment films 106, 206, 306, 401, 501, 601, 911 First electrode (pixel electrode)
107, 207, 307, 402, 502, 602, 912 Second electrode (common electrode)
108, 910 Insulating film 109, 211 Incident light 208, 308 Second insulating film 209, 309 First insulating film 210, 312 TFT element part 212, 310, 403, 503, 603 Opening part (contact hole part)
313 Transparent electrodes 404, 504, 505 Longitudinal direction 405 of linear pixel electrode Liquid crystal panel 406 Long axis direction of liquid crystal panel 407 Short axis direction of liquid crystal panel 408 Connector tape 409, 506, 604 1 pixel 701 Orientation direction of liquid crystal on upper substrate 702 Alignment direction 913 of the liquid crystal of the lower substrate Liquid crystal molecule 904 Polarizing plate 905, 906 Phase difference plate 907 Color filter

Claims (40)

A liquid crystal layer sandwiched between a first substrate and a second substrate; a first electrode formed on a surface of the second substrate on the liquid crystal layer side; and a second electrode, wherein the first electrode and the second electrode are In the liquid crystal device configured to be able to apply an electric field substantially parallel to the substrate surface to the liquid crystal layer,
The first electrode is formed on the second electrode in a linear shape having a predetermined line width via a second insulating film, the second electrode is formed in a rectangular shape, the first electrode, the second electrode At least one of the electrodes is a reflective electrode that reflects light incident from the first substrate side. A liquid crystal layer sandwiched between a first substrate and a second substrate, and a scanning signal line, an image signal line, a first electrode, a second electrode, and an active element formed on the surface of the second substrate on the liquid crystal layer side. In the liquid crystal device configured such that the first electrode and the second electrode can apply an electric field substantially parallel to the substrate surface to the liquid crystal layer,
The second electrode is formed over the entire display area of the liquid crystal device through the first insulating film so as to cover the scanning signal line, the image signal line, and the active element, and has an opening. One electrode is formed in a line shape having a predetermined line width in each pixel via a second insulating film on the second electrode, and the first electrode and the active element are formed through the opening of the second electrode. Are connected, and at least one of the first electrode and the second electrode is a reflective electrode that reflects light incident from the first substrate side.   3. The liquid crystal device according to claim 1, wherein 4 <L1 / W1 ≦ 40, where W1 is a line width of the first electrode and L1 is an electrode interval.   3. The liquid crystal device according to claim 1, wherein 0.005 ≦ L1 / W1 <0.2, where W1 is a line width of the first electrode and L1 is an electrode interval.   3. The liquid crystal device according to claim 1, wherein 0.1 μm ≦ L1 <1 μm is satisfied, where L1 is an interval between the first electrodes.   3. The liquid crystal device according to claim 1, wherein when the electrode interval between the first electrodes is L1, 8 μm <L1 ≦ 25 μm.   3. The liquid crystal device according to claim 2, wherein a plurality of openings in the second electrode exist in one pixel, and the plurality of linear first electrodes are connected to one same active element through each of the openings.   The liquid crystal device according to claim 1, wherein the first electrode also serves as a light shielding film.   The liquid crystal device according to claim 1, wherein the second electrode also serves as a light shielding film.   10. The liquid crystal device according to claim 1, wherein the longitudinal direction of the linear first electrode is non-parallel and non-orthogonal with any of the four sides of the liquid crystal panel.   The liquid crystal device according to claim 1, wherein each pixel has a parallelogram shape and each corner is not a right angle.   10. The liquid crystal according to claim 1, wherein an angle between the longitudinal direction of the linear first electrode and the longitudinal direction of the liquid crystal panel is β, and 3 ° ≦ β ≦ 87 °. apparatus.   The adjacent pixel is characterized in that the longitudinal direction of at least one linear first electrode is non-parallel to the longitudinal direction of the linear first electrode of the adjacent pixel. The liquid crystal device according to 1.   The liquid crystal device according to claim 1, wherein a shape of the linear first electrode is a “<” character.   The liquid crystal device according to claim 2, wherein the first insulating film has a flattening function so that the second electrode becomes a mirror surface.   The liquid crystal device according to claim 1, wherein the first electrode is a pixel electrode, and the second electrode is a common electrode.   3. The liquid crystal device according to claim 2, wherein the thickness of the first insulating film is 0.01 μm ≦ D1 ≦ 5 μm, where D1 is D1.   3. The liquid crystal device according to claim 1, wherein the thickness of the second insulating film is 0.01 μm ≦ D2 ≦ 5 μm, where D <b> 2 is D <b> 2.   3. The liquid crystal device according to claim 1, wherein one of the first insulating film and the second insulating film is made of SiOx or SiNx.   The liquid crystal device according to claim 1, wherein the second insulating film has a transmittance in a visible light region of 80% or more.   The liquid crystal device according to claim 1, wherein the second insulating film is a color filter.   The thickness of the liquid crystal layer is d, and the refractive index anisotropy of the liquid crystal is Δn, 0.1 μm ≦ Δn × d <0.2 μm. LCD device.   In the first substrate and the second substrate, an alignment film is formed on a surface in contact with the liquid crystal layer, and when an angle (pretilt angle) between the liquid crystal molecules in the liquid crystal layer and the substrate surface is θp, 10 degrees <θp ≦ The liquid crystal device according to any one of claims 1 to 22, wherein the liquid crystal device is 90 degrees.   When the angle between the alignment axis of the alignment film formed on the inner surface of the first substrate and the alignment axis of the alignment film formed on the inner surface of the second substrate is α, 0 degree ≦ α <180 degrees. The liquid crystal device according to any one of claims 1 to 23.   The liquid crystal device according to any one of claims 1 to 24, wherein the liquid crystal layer includes a liquid crystal material having a negative dielectric anisotropy and having a cyano group.   26. The liquid crystal device according to claim 1, wherein the liquid crystal layer includes a chiral liquid crystal material.   27. The liquid crystal device according to claim 1, wherein the alignment film is made of SiOx.   28. The liquid crystal device according to claim 1, wherein the second substrate is a silicon (Si) substrate.   The liquid crystal device according to any one of claims 1 to 28, wherein a transparent electrode having a constant potential is provided on a surface different from the liquid crystal layer of the first substrate.   30. The liquid crystal device according to claim 29, wherein the transparent electrode has a zero potential.   The liquid crystal device according to claim 29 or 30, wherein the transparent electrode is made of ITO.   32. The liquid crystal device according to claim 1, wherein the pixel pitch is 30 [mu] m or less.   33. The device according to claim 1, wherein an interval between the first electrodes is L1 and a thickness of the second insulating film is D2, and 5 ≦ L1 / D2 ≦ 30. Liquid crystal device.   34. A projection display device comprising the liquid crystal device according to any one of claims 1 to 33.   A light source, a light modulation device that modulates light from the light source, and a projection lens that projects light modulated by the light modulation device are provided, and the light modulation device is any one of claims 1 to 33. A projection display device using the liquid crystal device described in 1.   A polarizing plate is disposed on a different side of the first substrate from the liquid crystal layer, the liquid crystal layer is uniaxially aligned, and the uniaxial alignment direction and the transmission axis of the polarizing plate are at an angle of approximately 45 degrees, The liquid crystal device according to any one of claims 1 to 33, wherein a phase difference of the liquid crystal layer is approximately ¼ wavelength.   At least one retardation plate and a polarizing plate are sequentially arranged on the side of the first substrate different from the liquid crystal layer, and the retardation obtained by combining the liquid crystal layer and the retardation plate is in the visible light range. 34. The liquid crystal device according to claim 1, wherein the liquid crystal device has a quarter wavelength.   At least one retardation plate and a polarizing plate are sequentially disposed on a side of the first substrate different from the liquid crystal layer, and the retardation plate has a wavelength of approximately ¼ in a visible light region. Item 34. The liquid crystal device according to any one of items 1 to 33.   The liquid crystal device according to any one of claims 36 to 38, wherein a color filter corresponding to each pixel is formed on a surface of the first substrate on the liquid crystal layer side.   An electronic apparatus comprising the liquid crystal device according to any one of claims 36 to 39.

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