JP2009229890A - Liquid crystal device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lower the contrast of an image more when the image is viewed obliquely in a narrow viewing-angle display mode by optimizing retardation of viewing-angle control pixels in a lateral electric field type liquid crystal device. <P>SOLUTION: The liquid crystal device has, in a planar area between an element substrate and an opposite substrate, a plurality of display pixel areas and a viewing-angle control area wherein dark display is performed in the front direction of a display screen and luminance varies in an oblique direction of the display screen according to the oblique direction. In the display pixel areas and viewing-angle control pixel area of the element substrate, pixel electrodes and a common electrode are provided which are independently drive in the respective areas and arranged opposite each other with a dielectric layer interposed. In particular, the liquid crystal device has larger retardation in the viewing-angle pixel area than in the display pixel areas. Consequently, the contrast of the image when the display screen is obliquely viewed is made lower in the narrow viewing-angle display mode, and excellent narrow viewing-angle display effect is obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal device and an electronic apparatus capable of switching display modes of both a wide viewing angle and a narrow viewing angle.

  Currently, liquid crystal devices are widely used in electronic devices such as mobile phones, portable information terminals, and computer displays. Such a liquid crystal device is required to have a wide viewing angle characteristic when many people view the displayed image from various directions, and has a narrow viewing angle characteristic when the surrounding image is not desired to be viewed by surrounding people. Desired.

  Accordingly, a liquid crystal device that can switch between a display state with a wide viewing angle and a display state with a narrow viewing angle has been proposed (see, for example, Patent Documents 1 to 5).

  Japanese Patent Laid-Open No. 2004-228688 can switch between wide viewing angle display and narrow viewing angle display by providing RGB color pixels and W pixels as a single unit, and providing W pixels with different viewing angle characteristics from RGB color pixels. Possible vertical alignment or twist nematic liquid crystal display devices are described.

  Patent Documents 2 to 4 include RGB pixels and viewing angle control pixels, and the viewing angle control pixels are aligned so that liquid crystal molecules are tilted in the vertical and horizontal directions, thereby adjusting the viewing angle in the vertical and horizontal directions. An FFS (Fringe Field Switching) type liquid crystal display device capable of performing the above is described. In such a liquid crystal display device, a control voltage is applied to the viewing angle control pixels via viewing angle control lines that are separate from the RGB pixels. Thereby, the liquid crystal molecules can be tilted in the vertical direction or the horizontal direction, and the viewing angle can be controlled.

  Patent Document 5 discloses a liquid crystal display device capable of preventing a display content from being stolen by looking into another person by making a fixed pattern unrelated to the display screen visible from directions other than the front. Is described.

JP 2007-79525 A JP 2007-17836 A JP 2007-178738 A JP 2007-178739 A JP 2003-233074 A

  By the way, in a general liquid crystal device, the retardation (product Δnd of the liquid crystal layer thickness d and the refractive index anisotropy Δn) is optimized by changing the thickness of the liquid crystal layer and the liquid crystal material. Is done.

  However, in the FFS mode liquid crystal device having both the wide viewing angle display mode and the narrow viewing angle display mode, considerations regarding retardation of the viewing angle control pixel suitable for the viewing angle control effect have not yet been made in relation to the retardation of the display pixel. In addition, Patent Documents 1 to 5 described above do not mention this point.

  The present invention has been made in view of the above points, and by optimizing the retardation of the viewing angle control pixel in relation to the retardation of the display pixel, in the narrow viewing angle display mode, the display screen is in the normal direction. It is an object of the present invention to provide a lateral electric field type liquid crystal device capable of further reducing the contrast of an image when viewed from an oblique direction, and an electronic apparatus to which the liquid crystal device is applied.

  In one aspect of the present invention, in a liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates, at least one display pixel region and a front surface of the pair of substrate surfaces are included in a planar region of the pair of substrates. At least one viewing angle control pixel region that performs dark display in the direction and changes in luminance according to the oblique direction in an oblique direction with respect to a normal direction of the pair of substrate surfaces, and one of the pair of substrates The display pixel region has a pair of electrodes for driving the liquid crystal, and the viewing angle control pixel region also has a pair of electrodes for driving the liquid crystal layer, and the pair of electrodes of the viewing angle control pixel region and the pair of electrodes The pair of electrodes in the display pixel region are driven independently, and the retardation of the viewing angle control pixel region is larger than that of the display pixel region.

  In the above liquid crystal device, when an appropriate voltage is applied between the pair of electrodes in the display pixel region, bright display with the highest transmittance or luminance is performed when the display screen is viewed from the front direction, and the display screen is When viewed from an oblique direction with respect to the normal direction, bright display according to the polar angle is performed. In addition, when an appropriate voltage is applied between the pair of electrodes in the viewing angle control region, dark display is performed when the display screen is viewed from the front direction, and when the display screen is viewed from an oblique direction with respect to the normal direction. The luminance changes according to the polar angle. For example, in this case, the luminance increases (becomes bright display) as the polar angle increases, and the luminance decreases (dark display) as the polar angle increases further. Thus, the pair of electrodes in the viewing angle control pixel region and the pair of electrodes in the display pixel region are driven independently.

  For this reason, when viewing angle control by the viewing angle control area is not performed, an image formed in the display pixel area is not restricted by the viewing angle control area and is viewed at a wide viewing angle. On the other hand, when viewing angle control is performed, an image formed in the display pixel region is viewed without restriction because a high contrast is obtained because the viewing angle control region is dark when the display screen is viewed from the front. . However, when the display screen is viewed from an oblique direction with respect to the normal direction, the brightness changes in the viewing angle control region and the contrast of the image decreases, so that the image cannot be viewed.

  In this liquid crystal device, the display pixel region has a pair of electrodes for driving the liquid crystal, and the viewing angle control pixel region is also provided with a pair of electrodes for driving the liquid crystal layer, forming a so-called lateral electric field type liquid crystal device. Here, the pair of electrodes in the viewing angle control pixel region and the pair of electrodes in the display pixel region are driven independently as described above. As a preferred example, an FFS liquid crystal device as an example of a transverse electric field method can be configured by arranging the pair of electrodes to face each other with a dielectric layer interposed therebetween.

  In particular, in this liquid crystal device, the retardation of the viewing angle control pixel region is larger than the retardation of the display pixel region. Here, the retardation of the viewing angle control pixel region is the product of the refractive index anisotropy Δn of the liquid crystal layer and the thickness of the liquid crystal layer in the viewing angle control pixel region. The retardation of the display pixel region is the product of the refractive index anisotropy Δn of the liquid crystal layer and the thickness of the liquid crystal layer in the display pixel region. When the refractive index anisotropy Δn of the liquid crystal layer is constant between the viewing angle control pixel region and the display pixel region, the thickness of the liquid crystal layer in the viewing angle control pixel region is larger than the thickness of the liquid crystal layer in the display pixel region. By doing so, the retardation of the viewing angle control pixel region can be made larger than the retardation of the display pixel region. Accordingly, in the narrow viewing angle display mode, for example, the display screen is inclined with respect to the normal direction (particularly, polar angles +40 [°] to +60 [°] and polar angles −40 [°] to −60 [°]. ), The contrast of the image viewed from the oblique direction can be further reduced, and a good narrow viewing angle display effect can be obtained.

In a preferred example, in order to obtain a good narrow viewing angle display effect, the retardation Re ₁ of the viewing angle control pixel region is preferably set within a range of 0.45 to 0.65 [μm]. In this case, the retardation Re ₂ of the display pixel region is preferably set to 0.3 [μm] ≦ Re ₂ <0.45 [μm] in order to obtain a high-quality display image. In order to obtain a better narrow viewing angle display effect, it is optimal to set the retardation Re ₁ of the viewing angle control pixel region to about 0.46 [μm] when the driving voltage of the viewing angle control pixel region is set to 5V. In addition, when the driving voltage of the viewing angle control pixel region is set to 10 V, it is optimal to set the retardation Re ₁ of the viewing angle control pixel region to approximately 0.50 [μm]. When the drive voltage is set to 15 V, it is optimal to set the retardation Re ₁ of the viewing angle control pixel region to approximately 0.52 [μm]. As a result, the viewing angle control pixel region in a direction oblique to the normal direction of the display screen (in particular, a direction of polar angle +40 [°] to +60 [°] and polar angle −40 [°] to −60 [°]). The luminance (or transmittance) is the highest, and the display screen is inclined with respect to the normal direction (particularly, polar angle +40 [°] to +60 [°] and polar angle −40 [°] to −60 [°]). ), The contrast of the image can be minimized, and a better narrow viewing angle display effect can be obtained.

  In one aspect of the liquid crystal device, a color filter layer for color display that adjusts a thickness of the liquid crystal layer is provided in the display pixel region in the other substrate of the pair of substrates, The color filter layer is not provided in the viewing angle control pixel region, and the thickness of the liquid crystal layer in the viewing angle control pixel region is larger than the thickness of the liquid crystal layer in the display pixel region.

  In this aspect, on the other of the pair of substrates, a color filter layer for color display having a certain thickness is provided in the display pixel region, and a color filter layer is provided in the viewing angle control pixel region. It is not done. As described above, by selectively providing the color filter layer having a certain thickness in the display pixel region and the viewing angle control pixel region on the other substrate, the thickness of the liquid crystal layer in the viewing angle control pixel region can be reduced. Is set larger than the thickness of the liquid crystal layer. Thereby, the retardation of the viewing angle control pixel region can be easily made larger than the retardation of the display pixel region.

  In another aspect of the liquid crystal device, at least one of the pair of substrates is a liquid crystal layer thickness adjustment in which a thickness of the liquid crystal layer in the display pixel region is smaller than a thickness of the liquid crystal layer in the viewing angle control pixel region. Having a layer. Thereby, the retardation of the viewing angle control pixel region can be easily made larger than the retardation of the display pixel region.

  In a preferred example, a direction of an electric field generated between the pair of electrodes in the viewing angle control pixel region is a direction intersecting an initial alignment direction of liquid crystal molecules constituting the liquid crystal layer and the pair of substrates. Along the normal direction of the surface. In this aspect, when a voltage is applied between the pair of electrodes in the viewing angle control region, the liquid crystal molecules are aligned in the normal direction of the pair of substrate surfaces, so that dark display is performed when the display screen is viewed from the front direction. When the display screen is viewed from an oblique direction with respect to the normal direction, the luminance changes according to the polar angle.

  In another aspect of the present invention, an electronic device including the above-described liquid crystal device as a display portion can be configured. According to this configuration, for example, it has both wide viewing angle and narrow viewing angle display modes, and in the narrow viewing angle display mode, it further reduces the contrast of the image when the display screen is viewed obliquely with respect to the normal direction. It is possible to configure an electronic device capable of

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Configuration of liquid crystal device]
First, a schematic configuration of a liquid crystal device 1 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing a schematic configuration of a liquid crystal device 1 according to the present embodiment. In FIG. 1, the viewing angle control line 26 is indicated by a solid line for convenience.

  The liquid crystal device 1 is an FFS (Fringe-Field Switching) type liquid crystal device as an example of a horizontal electric field type. The liquid crystal device 1 includes an element substrate 11 having a TFT (Thin Film Transistor) element that controls switching of display pixels and a counter substrate 12 bonded together via a frame-shaped sealing material (not shown), and the element substrate 11 and the counter substrate. For example, a nematic liquid crystal layer 13 having a positive dielectric anisotropy is sandwiched in a region partitioned by a sealing material between the first and second layers. An image display area (area surrounded by an alternate long and short dash line) V for displaying an image is formed inside the sealing material in the liquid crystal device 1.

  The element substrate 11 has an overhang region 11 h that projects outward from one end of the counter substrate 12. A data line driving circuit 16, a scanning line driving circuit 17, a viewing angle control line driving circuit 18, a plurality of external connection wirings 19, and an FPC (Flexible Printed Circuits) 20 are provided on the surface of the overhanging region 11h on the counter substrate 12 side. Each is formed or implemented. The data line driving circuit 16, the scanning line driving circuit 17, and the viewing angle control line driving circuit 18 are electrically connected to the FPC 20 via each external connection wiring 19. A first polarizing plate 14 is disposed on the element substrate 11 opposite to the liquid crystal layer 13 side, and a second polarizing plate 15 is disposed on the counter substrate 12 opposite to the liquid crystal layer 13 side. . On the opposite side of the first polarizing plate 14 from the element substrate 11 side, a backlight (not shown) as an illumination device is disposed.

  Next, an electrical configuration of the liquid crystal device 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is an equivalent circuit diagram showing an electrical configuration of the liquid crystal device 1.

  In the image display area V of the liquid crystal device 1, a plurality of display pixels (display pixel areas) Pa and viewing angle control pixels (viewing angle control pixel areas) Pb are arranged in a matrix, and a plurality of data lines 24 and a plurality of data lines 24 are arranged. A viewing angle control line 26 and a plurality of scanning lines 25 are arranged in a grid pattern.

  The display pixel Pa has three sub display pixels (sub display pixel regions) Pc that output light of different colors, for example, R (red), G (green), and B (blue). The three sub display pixels Pc constituting the display pixel Pa, that is, the sub display pixels Pc of R, G, and B, are arranged in this order along one direction (in this example, the extending direction of the scanning line 25). . However, in the present invention, there is no limitation on the arrangement order of the sub-display pixels Pc of R, G, and B colors. Each sub display pixel Pc includes a pixel electrode 21 and a TFT element 23 for controlling the switching of the pixel electrode 21. The TFT element 23 includes a source electrode 23s, a gate electrode 23g, and a drain electrode 23d. The source electrode 23s is electrically connected to the data line 24. The gate electrode 23g is electrically connected to the scanning line 25. The drain electrode 23d is electrically connected to the pixel electrode 21.

  The viewing angle control pixel Pb is arranged corresponding to each of the plurality of display pixels Pa. In this example, each viewing angle control pixel Pb is located at a position adjacent to the B sub-display pixel constituting one arbitrary display pixel Pa and the extending direction of the scanning line 25 with respect to the one arbitrary display pixel Pa. It is arranged corresponding to the R sub-display pixel Pc constituting the other provided display pixel Pa. The viewing angle control pixel Pb includes the pixel electrode 22 but does not include the TFT element 23. The viewing angle control pixel Pb is driven independently of the sub display pixel Pc through a viewing angle control line driving circuit 18 and a viewing angle control line 26 described later.

  Each data line 24 supplies the image signals S1 to Sn supplied from the data line driving circuit 16 to the sub display pixel Pc. The scanning line 25 supplies the scanning signals G1 to Gm supplied from the scanning line driving circuit 17 to the sub display pixel Pc.

  The viewing angle control line 26 has a comb-like shape and includes a plurality of comb-tooth portions 26a. Each comb-tooth portion 26 a is directly and electrically connected to each viewing angle control pixel Pb that forms a column in the extending direction of the data line 24. The viewing angle control line 26 is electrically connected to the viewing angle control line drive circuit 18.

  The viewing angle control line driving circuit 18 supplies the viewing angle control signal K to the viewing angle control line 26 in the narrow viewing angle display mode, while being independent of the data line driving circuit 16 and the scanning line driving circuit 17, while in the wide viewing angle display mode. A viewing angle control signal (for example, an OFF signal) K is supplied to the viewing angle control line 26, in other words, the supply of the viewing angle control signal K is stopped. In a preferred example, the viewing angle control line driving circuit 18 includes a switching element such as a transistor capable of switching (ON / OFF) an electric signal. In this case, the viewing angle control line driving circuit 18 can supply a viewing angle control signal (ON / OFF signal) K to the viewing angle control line 26 by turning on / off the switching element. In the present embodiment, the viewing angle control line driving circuit 18 for driving the pixel electrode 22 is provided in the liquid crystal device 1. However, the present invention is not limited to this, and in the present invention, the viewing angle control line driving circuit 18 is connected to the FPC 20 or the FPC 20. It may be provided in an electronic device to be described later.

  Next, a detailed configuration of the liquid crystal device 1 will be described with reference to FIGS. 3 to 5.

  FIG. 3 shows a configuration of the liquid crystal device 1 including any one display pixel Pa composed of three sub display pixels Pc and one viewing angle control pixel Pb arranged corresponding to the one display pixel Pa. It is a top view. FIG. 4 is a cross-sectional view of a main part of the liquid crystal device 1 taken along a cutting line A-A ′ in FIG. 3. FIG. 5 is a cross-sectional view of a main part of the liquid crystal device 1 taken along a cutting line B-B ′ in FIG. 3.

  First, the configuration of the element substrate 11 is as follows.

  The element substrate 11 includes, for example, a substrate body 31 made of a translucent material such as glass, quartz, and plastic, and a gate insulating film 32 that is sequentially stacked from the surface of the substrate body 31 on the liquid crystal layer 13 side toward the liquid crystal layer 13 side. , A first interlayer insulating film 33, a second interlayer insulating film 34 as a dielectric layer, and an alignment film 35. The element substrate 11 includes a scanning line 25 formed on the surface of the substrate body 31 on the liquid crystal layer 13 side, a data line 24 formed on the surface of the gate insulating film 32 on the liquid crystal layer 13 side, and a viewing angle control line. 26, the semiconductor layer 36, the source electrode 37 and the drain electrode 38, the common electrode 39 formed on the surface of the first interlayer insulating film 33 on the liquid crystal layer 13 side, and the liquid crystal layer 13 side of the second interlayer insulating film 34. The pixel electrode 21 and the pixel electrode 22 formed on the surface are provided.

The gate insulating film 32 is made of a translucent material such as SiO ₂ (silicon oxide), for example, and covers the scanning lines 25 formed on the substrate body 31. The first interlayer insulating film 33 is made of a light-transmitting material such as SiN (silicon nitride), for example, and includes a gate insulating film 32, a data line 24 formed on the gate insulating film 32, a viewing angle control line 26, The semiconductor layer 36, the source electrode 37, and the drain electrode 38 are covered. The second interlayer insulating film 34 is formed of a translucent material such as photosensitive acrylic resin, for example, and includes a first interlayer insulating film 33 and a common electrode 39 formed on the first interlayer insulating film 33. Covering. The alignment film 35 is formed of a translucent material such as a polyimide resin, for example, and covers the second interlayer insulating film 34 and the pixel electrode 21 and the pixel electrode 22 formed on the second interlayer insulating film 34. Yes. The surface on the liquid crystal layer 13 side of the alignment film 35 is subjected to an alignment treatment that defines the initial alignment direction of the liquid crystal molecules 13a constituting the liquid crystal layer 13 in a predetermined direction (in this example, the extending direction of the data lines 24). ing.

  As shown in FIG. 3, the scanning lines 25 are arranged along the respective short axis directions of the sub display pixel Pc and the viewing angle control pixel Pb when viewed in plan. The scanning line 25 overlaps the channel region of the semiconductor layer 36 with the gate insulating film 32 interposed therebetween. As shown in FIG. 3, the data line 24 is arranged along the major axis direction of the sub display pixel Pc when seen in a plan view. As shown in FIG. 3, the viewing angle control line 26 is arranged along the major axis direction of the viewing angle control pixel Pb when viewed in plan.

  The semiconductor layer 36 is formed of a semiconductor such as amorphous silicon, and has a channel region formed without implanting impurities and a source region and a drain region formed by implanting impurities.

  The source electrode 37 is branched from the data line 24 and is electrically connected to the source region of the semiconductor layer 36. The drain electrode 38 is electrically connected to the drain region of the semiconductor layer 36, and is electrically connected to the pixel electrode 21 through a contact hole H 1 that penetrates the first interlayer insulating film 33 and the second interlayer insulating film 34. Has been.

  The common electrode 39 is formed of a light-transmitting conductive material such as ITO (Indium Tin Oxide), for example, and covers the first interlayer insulating film 33. The common electrode 39 is provided at a position corresponding to the contact hole H1 and includes an opening 39a for insulating the common electrode 39 from the pixel electrodes 21, 22 and the drain electrode 38. The common electrode 39 has, for example, a predetermined reference voltage used for driving the liquid crystal layer 13 (for example, a predetermined constant voltage or 0 V, or a predetermined constant potential and another predetermined constant potential different from the predetermined constant voltage). Is periodically applied (a signal that switches every frame period or every field period).

  Similar to the common electrode 39, the pixel electrode 21 is formed of a light-transmitting conductive material such as ITO. The pixel electrode 21 is formed on the second interlayer insulating film 34 in the sub display pixel Pc, and has a substantially ladder-like planar shape. The pixel electrode 21 includes a pair of main line portions 21a and a plurality of strip-shaped portions 21b. Each of the pair of main line portions 21 a is disposed at an end portion in the major axis direction of the sub display pixel Pc and extends in a direction substantially parallel to the extending direction of the scanning lines 25. In addition, one main line portion 21a arranged in the vicinity of the scanning line 25 in the pair of main line portions 21a is electrically connected to the drain electrode 38 of the TFT element 23 through the contact hole H1.

  Each belt-like portion 21b has a belt-like planar shape, and extends at a predetermined inclination angle with respect to the major axis direction of the sub display pixel Pc (or the extending direction of the data line 24). Further, the strips 21b are arranged in parallel at a certain interval in the minor axis direction of the sub display pixel Pc (in other words, the extending direction of the scanning line 25), and are substantially parallel to each other. Is arranged. For this reason, a slit (opening) 21s is formed between the strips 21b adjacent to each other in the short axis direction of the sub display pixels Pc. Both ends of each strip portion 21b are electrically connected to each of the pair of main line portions 21a. Of the plurality of strip-like portions 21b, some of the strip-like portions 21b arranged at the end in the minor axis direction of the sub display pixel Pc are only on one of the pair of main-line portions 21a. Electrically connected. Further, the electrode pitch L6 of each strip portion 21b is set to 2 to 8 [μm] in order to obtain a high-quality display. Here, the electrode pitch L6 of each strip 21b is the distance between the width L4 of the strip 21b in the approximately short axis direction of the sub display pixel Pc and the band 21b adjacent to each other in the approximately short axis direction of the sub display pixel Pc ( = Slit 21s width) is equal to the sum of L5.

  Similarly to the common electrode 39, the pixel electrode 22 is formed of a light-transmitting conductive material such as ITO. The pixel electrode 22 is formed on the second interlayer insulating film 34 in the viewing angle control pixel Pb, and has a substantially ladder-like planar shape. The pixel electrode 22 includes a frame-shaped portion 22a having a substantially rectangular frame-shaped planar shape, and a plurality of strip-shaped portions 22b arranged inside the frame-shaped portion 22a. The frame portion 22a is electrically connected to a branch portion 26ab branched from the comb-tooth portion 26a of the viewing angle control line 26 through a contact hole H1 that penetrates the first interlayer insulating film 33 and the second interlayer insulating film 34. Yes.

  Each belt-like portion 22b has a belt-like planar shape and extends so as to be substantially parallel to each other along the minor axis direction of the viewing angle control pixel Pb. Further, the strips 22b are arranged in parallel at a certain interval in the major axis direction of the viewing angle control pixel Pb (in other words, the extending direction of the comb-tooth portion 26a of the data line 24 or the viewing angle control line 26). Yes. For this reason, slits (openings) 22s are formed between the strips 22b adjacent to each other in the major axis direction of each viewing angle control pixel Pb. Both ends of each belt-like portion 22b are electrically connected to a portion of the frame-like portion 22a extending along the long axis direction of the viewing angle control pixel Pb. The electrode pitch L3 of the strip portion 22b is preferably larger than the electrode pitch L6 of the strip portion 21b of the sub display pixel Pc in order to obtain an appropriate narrow viewing angle display effect. Here, the electrode pitch L3 of the band-like portion 22b is the distance L1 between the band-like portions 22b in the major axis direction of the viewing angle control pixel Pb and the band-like portions 22b adjacent in the major axis direction of the viewing angle control pixel Pb (= slit 22s). The width is equal to the sum of L2.

  For example, when the electrode pitch L6 of each strip portion 21b of the sub display pixel Pc is set to 2 to 8 [μm], the electrode pitch L3 of the strip portion 22b is set within a range of 10 to 30 [μm]. It is preferable that it is set to about 20 [μm]. In order to obtain an appropriate narrow viewing angle display effect, the interval L2 between the strips 22b adjacent to each other in the major axis direction of the viewing angle control pixel Pb is substantially equal to the width L1 of the strip 22b or the width of the strip 22b. A slightly larger value than L1 is desirable.

  As described above, in this liquid crystal device 1, by applying a voltage between the strips 21 b and 22 b and the common electrode 39, an electric field (lateral electric field) is generated between the pixel electrodes 21 and 22 and the common electrode 39. This drives the liquid crystal molecules 13a. As described above, in the liquid crystal device 1, the pixel electrode 21 and the common electrode 39, and the pixel electrode 22 and the common electrode 39 constitute an FFS type electrode structure, respectively.

  Next, the configuration of the counter substrate 12 is as follows.

  As shown in FIG. 4, the counter substrate 12 includes a substrate body 41 made of the same material as the substrate body 31, and a light shielding film 42 sequentially stacked from the surface of the substrate body 41 on the liquid crystal layer 13 side to the liquid crystal layer 13 side. A color filter layer 43 and an alignment film 44.

  The light shielding film 42 is formed of a material having a light shielding property, and is disposed on the surface on the liquid crystal layer 13 side of the substrate body 41 at a position for partitioning each sub display pixel Pc and a position for partitioning each viewing angle control pixel Pb. Has been. The color filter layer 43 includes color filter layers 43R, 43G, and 43B for R, G, and B colors. The color filter layers 43R, 43G, and 43B each have a constant thickness t and are provided corresponding to each sub display pixel Pc. However, the color filter layer 43 is not provided in a region corresponding to each viewing angle control pixel Pb. The alignment film 44 has a certain thickness and is made of a light-transmitting material such as a polyimide resin. On the surface of the alignment film 44 on the liquid crystal layer 13 side, the initial alignment direction of the liquid crystal molecules 13a is a predetermined direction (in this example, the extending direction of the data line 24) and is an antiparallel direction to the alignment film 35. Processing has been applied.

[Operation of liquid crystal device]
Next, the operation of the liquid crystal device 1 will be described with reference to FIGS. 6 (a) and 6 (b).

  FIG. 6A is a graph showing an example of viewing angle characteristics of transmittance (or luminance) of the sub display pixel Pc and the viewing angle control pixel Pb when a certain voltage is applied to the sub display pixel Pc and the viewing angle control pixel Pb. It is. In FIG. 6A, the vertical axis indicates the transmittance, and the horizontal axis indicates data from the normal direction when the orientation of the normal direction (front direction) of the display surface of the liquid crystal device 1 is 0 [°]. A polar angle [°] shifted by ± θ in the direction substantially orthogonal to the extending direction of the line 24 or the absorption axis direction of the second polarizing plate 15 is shown. In FIG. 6A, the transmittance shown on the vertical axis becomes higher as it goes upward in the figure. FIG. 6B is a graph showing an example of contrast viewing angle characteristics when the viewing angle control pixel Pb is driven and when it is not driven. In FIG. 6B, the vertical axis indicates the contrast, and the horizontal axis indicates the same polar angle [°] as in FIG.

  The light emitted from the backlight is converted into linearly polarized light by the first polarizing plate 14 and enters the liquid crystal layer 13. Here, in the non-drive state in which no voltage is applied between the pixel electrode 21 and the common electrode 39 in the sub display pixel Pc, the linearly polarized light incident on the liquid crystal layer 13 is deflected by the liquid crystal layer 13 as in the incident state. Then, the light is emitted from the liquid crystal layer 13. The linearly polarized light is blocked by the second polarizing plate 15 because its deflection direction is parallel to the absorption axis of the second polarizing plate 15. Therefore, in the sub display pixel Pc, dark display is performed when not driven. The sub display pixel Pc is darkly displayed both when viewed from the front and when viewed from an oblique direction.

  Further, in the case of driving in which a voltage is applied between the pixel electrode 21 and the common electrode 39 in the sub display pixel Pc, the liquid crystal molecules 13a in the initial alignment state along a direction substantially parallel to the major axis direction of the pixel electrode 21. Is reoriented in the direction intersecting with the major axis direction of the pixel electrode 21 (substantially orthogonal in this example) by rotating on the substrate surfaces of the element substrate 11 and the counter substrate 12 as indicated by an arrow A1 in FIG. . As a result, the linearly polarized light incident on the liquid crystal layer 13 is given a predetermined phase difference by the liquid crystal layer 13, converted into linearly polarized light orthogonal to the deflection direction at the time of incidence, emitted from the liquid crystal layer 13, and further the second polarized light. It passes through the plate 15. Therefore, in the sub display pixel Pc, a bright display visually recognized as display light at the time of driving is performed. Here, in the sub display pixel Pc, as shown in FIG. 6A, the transmittance (or luminance) is highest when viewed from the front, and the polar angle is increased when viewed from the oblique direction. The transmittance (or luminance) is lowered.

  On the other hand, in the non-driving state where no voltage is applied between the pixel electrode 22 and the common electrode 39 in the viewing angle control pixel Pb, dark display is performed in the viewing angle control pixel Pb as described above. The viewing angle control pixel Pb is darkly displayed both when viewed from the front and when viewed from an oblique direction (an oblique direction with respect to the normal direction of the display surface of the liquid crystal device 1).

  Further, in the case of driving in which a voltage is applied between the pixel electrode 22 and the common electrode 39 in the viewing angle control pixel Pb, initial alignment is performed along a direction intersecting (substantially orthogonal in this example) with the extending direction of the strip portion 22b. The liquid crystal molecules 13a in the state are reoriented in the vertical direction (normal direction) with respect to the substrate surfaces of the element substrate 11 and the counter substrate 12, as indicated by an arrow A2 shown in FIG. Here, as shown in FIG. 6A, the viewing angle control pixel Pb is dark when viewed from the front because there is no phase difference change in the liquid crystal layer 13. Further, the viewing angle control pixel Pb responds to a change in phase difference in the liquid crystal layer 13 when viewed from an oblique direction in the absorption axis direction of the second polarizing plate 15 (oblique direction with respect to the normal direction of the display surface of the liquid crystal device 1). The luminance (or transmittance) changes according to the polar angle, that is, the luminance increases (becomes bright display) as the polar angle increases, and the luminance decreases (becomes dark display) as the polar angle increases further. Become). In the viewing angle control pixel Pb in this example, the peak of transmittance exists in each range of the polar angle +40 [°] to +60 [°] and the polar angle −40 [°] to −60 [°].

  As described above, in this embodiment, the viewing angle characteristic can be changed by driving and non-driving the viewing angle control pixel Pb. That is, when the viewing angle control pixel Pb is not driven, an image formed in the image display region V by appropriately driving or non-driving each sub display pixel Pc is viewed from an oblique direction even when viewed from the front. Sometimes it is visible. As shown in FIG. 6B, the contrast when the viewing angle control pixel Pb is not driven is the highest when viewed from the front, and the polar angle increases when viewed from the oblique direction. Lower. In this example, when the viewing angle control pixel Pb is not driven, the wide viewing angle display mode in which the contrast exceeds about 20 within the range of the polar angle −80 [°] to +80 [°] can be set.

  On the other hand, when the viewing angle control pixel Pb is driven, an image formed in the image display region V by appropriately driving or non-driving each sub display pixel Pc is viewed when viewed from the front, and is viewed from an oblique direction. When viewed, the contrast decreases and the image becomes invisible. Note that the contrast when the viewing angle control pixel Pb is driven is the highest when viewed from the front as shown in FIG. 6B, and sharply increases as the polar angle increases when viewed from an oblique direction. It becomes low. In this example, when the viewing angle control pixel Pb is driven, the narrow viewing angle display mode that is very difficult to see and has a contrast of less than about 2 when the polar angle is smaller than −40 [°] or larger than +40 [°]. It can be.

[Optimization of viewing angle control pixel retardation]
As described above, in the viewing angle control pixel Pb, luminance (or brightness) that makes it very difficult to see an image within each range of the polar angle +40 [°] to +60 [°] and the polar angle −40 [°] to −60 [°]. There is a peak of transmittance. Therefore, in the present embodiment, the luminance (or transmittance) of the viewing angle control pixel Pb is set in each range of the polar angle +40 [°] to +60 [°] or the polar angle −40 [°] to −60 [°]. The optimum value of the retardation Re ₁ of the viewing angle control pixel Pb to be maximized was examined. Here, the retardation Re ₁ of the viewing angle control pixel Pb is a product of the refractive index anisotropy Δn of the liquid crystal layer 13 and the thickness d1 of the liquid crystal layer 13 in the viewing angle control pixel Pb. Hereinafter, this point will be described with reference to FIGS.

FIG. 7A illustrates a polar angle +40 [°] to +60 [°] or a polar angle −40 [°] when the driving (applied) voltage [V] for driving the viewing angle control pixel Pb is appropriately changed. -60 is a graph showing the relationship between the direction of the luminance (or transmittance) of the viewing angle control pixels Pb and its retardation Re ₁ of [°]. In FIG. 7A, the vertical axis represents the luminance (or transmittance) of the viewing angle control pixel Pb in the direction of polar angle +40 [°] to +60 [°] or polar angle −40 [°] to −60 [°]. The horizontal axis represents the retardation Re ₁ of the viewing angle control pixel Pb. In FIG. 7A, the luminance shown on the vertical axis increases as it goes upward in the figure. In the example of the graph shown in FIG. 7A, the electrode pitch L3 of the band-like portion 22b of the viewing angle control pixel Pb is approximately 20 [μm] {here, the width L1 of the band-like portion 22b of the viewing angle control pixel Pb (= approximately). 9 [μm]) and the distance L2 (= approximately 11 [μm]) between the strips 22b adjacent to each other in the major axis direction of the viewing angle control pixel Pb}. FIG. 7B shows the relationship between the drive voltage [V] and the optimum value of the retardation Re ₁ of the viewing angle control pixel Pb when the driving (application) voltage [V] for driving the viewing angle control pixel Pb is appropriately changed. An example of the graph which shows a relationship is shown. In FIG. 7B, the vertical axis represents the retardation Re ₁ of the viewing angle control pixel Pb, and the horizontal axis represents the drive voltage [V] of the viewing angle control pixel Pb.

7A and 7B, when the driving voltage of the viewing angle control pixel Pb is 5V, the polar angle +40 [°] to +60 [°] and the polar angle −40 [°] to −60 [° most lower contrast of the image as viewed in the direction of, the optimum value of the retardation Re ₁ of the viewing angle control pixel Pb is approximately 0.46 [[mu] m]. Further, when the driving voltage of the viewing angle control pixel Pb is 10 V, an image when viewed from the polar angle +40 [°] to +60 [°] and the polar angle −40 [°] to −60 [°]. The optimum value of the retardation Re ₁ of the viewing angle control pixel Pb that makes the contrast of the lowest is approximately 0.50 [μm]. Further, when the driving voltage of the viewing angle control pixel Pb is 15V, the image is viewed from the polar angle +40 [°] to +60 [°] and the polar angle −40 [°] to −60 [°]. The optimum value of the retardation Re ₁ of the viewing angle control pixel Pb that makes the contrast of the lowest is approximately 0.52 [μm].

Thus, the contrast of the image when viewed from the polar angle +40 [°] to +60 [°] and the polar angle −40 [°] to −60 [°] depending on the driving voltage for driving the viewing angle control pixel Pb. The optimum value of the retardation Re ₁ of the viewing angle control pixel Pb is different, but the retardation Re ₁ of the viewing angle control pixel Pb is approximately in the range of 0.45 to 0.65 [μm]. The luminance of the viewing angle control pixel Pb in the diagonal direction of the display screen (particularly, the direction of polar angle +40 [°] to +60 [°] and polar angle −40 [°] to −60 [°]) is increased to display It is possible to further reduce the contrast of an image when the screen is viewed from an oblique direction (particularly, polar angle +40 [°] to +60 [°] and polar angle −40 [°] to −60 [°]). .

Note that in a general FFS type liquid crystal device, the optimum retardation of the display pixel suitable for display such as the balance of each color of R, G, and B, the luminance (the refractive index anisotropy Δn of the liquid crystal layer, and the liquid crystal in the display pixel) The product of the layer thickness (Re ₂₀ ) and Re ₂₀ are generally set to satisfy 0.3 [μm] ≦ Re ₂₀ <0.45 [μm]. Therefore, also in the present embodiment, in order to obtain a high-quality display image, the retardation Re ₂ of the sub display pixels Pc of R, G, and B colors is 0.3 [μm] ≦ Re ₂ <0.45 [μm]. ] Is set to satisfy. Here, the retardation Re ₂ of the sub display pixel Pc is a product of the refractive index anisotropy Δn of the liquid crystal layer 13 and the thickness d2 (<d1) of the liquid crystal layer 13 in the sub display pixel Pc.

From the above, the optimum retardation is different between the sub display pixel Pc and the viewing angle control pixel Pb, and it is desirable that the retardation Re ₁ of the viewing angle control pixel Pb is larger than the retardation Re ₂ of the sub display pixel Pc. Thereby, in the narrow viewing angle display mode, the display screen of the liquid crystal device 1 is viewed from an oblique direction (particularly, directions of polar angle +40 [°] to +60 [°] and polar angle −40 [°] to −60 [°]). The contrast of the image when viewed can be further reduced, and a good narrow viewing angle display effect can be obtained.

In a preferred example, when the retardation Re ₂ of the sub display pixel Pc is set to satisfy 0.3 [μm] ≦ Re ₂ <0.45 [μm], the retardation Re ₁ of the viewing angle control pixel Pb is 0. It is preferable to set within the range of .45 to 0.65 [μm]. In this case, in a more preferable example, when the driving voltage of the viewing angle control pixel Pb is set to 5 V, it is optimal to set the retardation Re ₁ of the viewing angle control pixel Pb to approximately 0.46 [μm]. When the driving voltage of the viewing angle control pixel Pb is set to 10 V, it is optimal to set the retardation Re ₁ of the viewing angle control pixel Pb to about 0.50 [μm], and the viewing angle control pixel Pb When the drive voltage is set to 15 V, it is optimal to set the retardation Re ₁ of the viewing angle control pixel Pb to approximately 0.52 [μm]. Accordingly, the luminance (or transmittance) of the viewing angle control pixel Pb in the oblique direction of the display screen (in particular, the polar angle +40 [°] to +60 [°] and the polar angle −40 [°] to −60 [°] direction). ) Is the highest, and the display screen is viewed in an oblique direction (particularly, polar angle +40 [°] to +60 [°] and polar angle −40 [°] to −60 [°]). The contrast can be made the lowest and a better narrow viewing angle display effect can be obtained.

By the way, in this embodiment, since the viewing angle control pixel Pb and the sub display pixel Pc use the same liquid crystal material to form the liquid crystal layer 13, the viewing angle control pixel Pb and the sub display pixel Pc refract the liquid crystal layer 13. The rate anisotropy Δn is constant. Therefore, in this embodiment, in order to make the retardation Re ₁ of the viewing angle control pixel Pb larger than the retardation Re ₂ of the sub display pixel Pc, the thickness d1 of the liquid crystal layer 13 in the viewing angle control pixel Pb is set to be the same as that in the sub display pixel Pc. The thickness is larger than the thickness d2 of the liquid crystal layer 13.

  Here, there are various methods for changing the relative thickness of the liquid crystal layer 13 between the viewing angle control pixel Pb and the sub display pixel Pc.

For example, as an example of this embodiment, the relative thicknesses of the liquid crystal layer 13 in the viewing angle control pixel Pb and the liquid crystal layer 13 in the sub display pixel Pc are made different depending on the presence or absence of the color filter layer 43. Specifically, in the counter substrate 12, a color filter layer 43 having a certain thickness t is provided at a position corresponding to each of the sub display pixels Pc of R, G, and B colors, while corresponding to the viewing angle control pixel Pb. In this position, the color filter layer 43 is not provided. As described above, by selectively providing the color filter layer 43 having the constant thickness t on the viewing angle control pixel Pb and the sub display pixel Pc on the counter substrate 12, the thickness d1 of the liquid crystal layer 13 in the viewing angle control pixel Pb. Can be made larger than the thickness d2 of the liquid crystal layer 13 in each sub-display pixel Pc. The thickness of the alignment film 44 provided on the counter substrate 12 is constant, and the surface on the liquid crystal layer 13 side of the alignment film 35 of the element substrate 11 has flatness. Accordingly, the retardation Re ₁ of the viewing angle control pixel Pb can be easily made larger than the retardation Re ₂ of the sub display pixel Pc.

  In the present invention, the method of changing the relative thickness of the liquid crystal layer 13 between the viewing angle control pixel Pb and the sub display pixel Pc is not limited to the above. For example, in the present invention, the liquid crystal layer thickness adjusting layer is provided on the surface of at least one of the element substrate 11 and the counter substrate 12 on the liquid crystal layer 13 side, thereby adjusting the thickness of the liquid crystal layer 13 in the display pixel Pa to the viewing angle control pixel. You may make it make it smaller than the thickness of the liquid crystal layer 13 in Pb.

  For example, FIG. 8 shows a cross-sectional view of a liquid crystal device 1s according to a modification corresponding to FIG. When this liquid crystal device 1s is compared with the liquid crystal device 1 described above, the configuration of the counter substrate is slightly different between the two and the other is the same. That is, in the counter substrate 12s of the liquid crystal device 1s, a liquid crystal layer thickness adjusting layer having a certain thickness is provided between the alignment film 44 and the color filter layer 43 in the display pixel Pa and the substrate body 41 in the viewing angle control pixel Pb. The overcoat layer 45 is provided. The overcoat layer 45 has a role of protecting the color filter layer 43 from corrosion and contamination due to chemicals and the like and ensuring flatness. Thereby, the thickness d3 of the liquid crystal layer 13 in each sub display pixel Pc can be made smaller than the thickness d2 of the liquid crystal layer 13 in the viewing angle control pixel Pb.

  FIG. 9 is a cross-sectional view of a liquid crystal device 1t according to another modification corresponding to FIGS. When this liquid crystal device 1t is compared with the above liquid crystal device 1s, the configuration of the counter substrate is slightly different between the two and the other is the same. That is, in the counter substrate 12t of the liquid crystal device 1t, the overcoat layer 45 is provided between the alignment film 44 and the color filter layer 43 in the display pixel Pa. The overcoat layer 45 is not provided between the pixel body Pb and the substrate body 41. Thereby, the thickness d3 of the liquid crystal layer 13 in each sub display pixel Pc can be surely made smaller than the thickness d1 of the liquid crystal layer 13 in the viewing angle control pixel Pb.

  FIG. 10 is a cross-sectional view of a liquid crystal device 1u according to another modification corresponding to FIGS. When this liquid crystal device 1u is compared with the above-described liquid crystal device 1s, the configuration of the counter substrate is slightly different between the two and the other is the same. That is, in the counter substrate 12u of the liquid crystal device 1u, the overcoat layer 45 is provided on the color filter layer 43 in the display pixel Pa and the substrate body 41 in the viewing angle control pixel Pb. Another overcoat layer 46 having a certain thickness is provided on the overcoat layer 45 in Pa. The alignment film 44 is provided on the other overcoat layer 46 in the display pixel Pa and on the overcoat layer 45 in the viewing angle control pixel Pb. Thereby, the thickness d4 of the liquid crystal layer 13 in each sub display pixel Pc can be more reliably made smaller than the thickness d2 of the liquid crystal layer 13 in the viewing angle control pixel Pb.

In the liquid crystal devices 1s, 1t, and 1u described above, the thickness of the alignment film 44 provided on the counter substrate 12s is constant, and the surface on the liquid crystal layer 13 side of the alignment film 35 of the element substrate 11 is flat. Have. Thereby, in the liquid crystal devices 1s, 1t, and 1u, the retardation Re ₁ of the viewing angle control pixel Pb can be easily made larger than the retardation Re ₂ of the sub display pixel Pc.

  In addition to these configurations, for example, in the present invention, in the element substrate 11, the liquid crystal in each sub display pixel Pc is made different in the thickness of various interlayer insulating films between the viewing angle control pixel Pb and the sub display pixel Pc. The thickness of the layer 13 may be made smaller than the thickness of the liquid crystal layer 13 in the viewing angle control pixel Pb.

[Modification]
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the present invention, when the position of the second interlayer insulating film 34 as a dielectric layer is used as a reference, the positional relationship among the sub display pixel Pc and the viewing angle control pixel Pb and the common electrode 39 is upside down. I do not care.

  In the present invention, the image display area V of any one of the liquid crystal devices including the liquid crystal devices 1, 1s, 1t, and 1u is divided into a plurality of display areas, and separate viewing angle control is performed for each of the divided display areas. (That is, narrow viewing angle control and wide viewing angle control) can be performed.

  This point will be described with reference to FIGS. 11 and 12. FIG. 11 is a circuit diagram of a viewing angle control equivalent circuit 600 showing an electrical configuration of the viewing angle control line driving circuit 18 according to a modification of the present invention and each viewing angle control line 26 and the like electrically connected thereto. . In FIG. 11, the display pixels Pa and the like are not shown in the image display area V.

  In this visual angle control equivalent circuit 600, a plurality of visual angle control lines to which respective visual angle control signals {K1, K2, K3,..., Kn-2, Kn-1, Kn; (n is a natural number)} are supplied. 26 is provided. Each viewing angle control line 26 is directly and electrically connected to the pixel electrode 22 of each viewing angle control pixel Pb that forms a column in the extending direction, and is also electrically connected to the viewing angle control line drive circuit 18. Yes.

  As a result, the viewing angle control signals K1 and K2 that are either ON or OFF for each viewing angle control line 26 through the viewing angle control line driving circuit 18 and independently of the data line driving circuit 16 and the scanning line driving circuit 17. , K3,..., Kn-2, Kn-1, and Kn can be supplied. Here, for example, by supplying (ON) a viewing angle control signal from the viewing angle control line driving circuit 18 to the pixel electrode 22 through the viewing angle control line 26, the narrow viewing angle display mode can be easily realized. On the other hand, by stopping (OFF) the supply of the viewing angle control signal from the viewing angle control line driving circuit 18 to the pixel electrode 22 through the viewing angle control line 26, the wide viewing angle display mode can be realized.

  Therefore, in the liquid crystal device having the viewing angle control equivalent circuit 600, for example, the so-called multiple screen display technique is used to divide the image display region V into a plurality of display regions, and different images for each of the divided display regions. In the case of display, different viewing angle control signals (ON signal and OFF signal) are simultaneously supplied to the viewing angle control line 26 through the viewing angle control line driving circuit 18 for each of the divided display areas.

  For example, FIG. 12A shows an example in which the liquid crystal device 1x having the viewing angle control equivalent circuit 600 is applied to the navigation system 710 of the vehicle 700. FIG. 12B is a plan view of the display screen 710v of the navigation system 710 when the navigation system 710 is viewed from the direction of the arrow Yv in FIG.

  A vehicle interior 700e of the vehicle 700 includes a driver's seat 700a, a passenger seat 700b disposed adjacent to the driver's seat 700a, a rear seat 700c located at the rear of the driver seat 700a and the passenger seat 700b, and a driver seat 700a. And a dashboard 700d positioned in front of the passenger seat 700b, and a navigation system 710 installed at a substantially central portion of the dashboard. The navigation system 710 has a display screen 710v on which video is displayed. In the navigation system 710, the liquid crystal device 1x is mounted at a position corresponding to the display screen 710v. Here, the driver of the driver's seat 700a and the passenger of the passenger seat 700b are positioned obliquely with respect to the display screen 710v of the navigation system 710, and the passenger of the rear seat 700c is displayed on the display screen 710v of the navigation system 710. On the other hand, it is located in the front direction.

  Now, it is assumed that on the display screen 710v of the navigation system 710, different images are displayed on the display areas V1 and V2 obtained by dividing the image display area V into two using a so-called two-screen display technique. For example, the display area V2 located on the driver's seat 700a side displays a map that guides the destination and the like, and the display area V1 located on the passenger seat 700b side displays images (TV programs, movies, etc.) that are different from the map. Is displayed. In this case, a visual angle control signal (OFF signal) is supplied to each viewing angle control pixel Pb related to the display region V2 where the map is displayed through the corresponding viewing angle control line 26, while a video different from the map is displayed. A viewing angle control signal (ON signal) is supplied to the viewing angle control pixel Pb located in the display area V <b> 1 through the corresponding viewing angle control line 26. Thereby, wide viewing angle control is performed in the display area V2 where the map is displayed, while narrow viewing angle control is performed in the display area V1 where the video different from the map is displayed. As a result, only the map can be seen by the driver of the driver's seat 200a, and driving safety can be ensured. On the other hand, the passenger in the rear seat 700c can see both the map and the video. In the present invention, the configuration of the visual angle control equivalent circuit is not limited to that shown in FIG. 11, and various modifications can be made without departing from the spirit of the present invention.

  In the above embodiment, the extending direction of the strip portion 21b of the pixel electrode 21 is set to the data line 24 so that a narrow viewing angle display effect can be obtained when viewed from an oblique direction in the absorption axis direction of the second polarizing plate 15. The extending direction of the strip portion 22b of the pixel electrode 22 is defined as a direction substantially orthogonal to the extending direction of the data line 24. . However, the present invention is not limited to this. In the present invention, the pixel electrode 21 has a narrow viewing angle display effect when viewed from an oblique direction in the transmission axis direction (direction orthogonal to the absorption axis direction) of the second polarizing plate 15. The extending direction of the strip portion 21b is defined as a direction extending with a predetermined inclination angle with respect to the direction substantially orthogonal to the extending direction of the data line 24, and the extending direction of the strip portion 22b of the pixel electrode 22 May be defined in a direction substantially parallel to the extending direction of the data line 24.

  In the above embodiment, the three sub display pixels Pc constituting the display pixel Pa are arranged in one direction, and the viewing angle control pixel Pb is arranged in the one direction and adjacent to the display pixel Pa. However, the present invention is not limited to this, and in the present invention, these pixels may have other arrangements. For example, as shown in FIG. 13A, among the three sub display pixels Pc constituting the display pixel Pa, two sub display pixels Pc that output R (red) color light and G (green) color light are displayed. Sub-display pixels Pc that are arranged adjacent to one direction and that output B (blue) color light are arranged adjacent to each other in a direction substantially orthogonal to the one direction, and further, this B (blue) color light is output. The viewing angle control pixel Pb may be arranged adjacent to the sub display pixel Pc to be aligned in one direction.

  In the above embodiment, one viewing angle control pixel Pb is arranged for one display pixel Pa. However, the present invention is not limited to this, and in the present invention, three sub-displays constituting one display pixel Pa are provided. A viewing angle control pixel Pb may be arranged corresponding to each of the pixels Pc. For example, as shown in FIG. 13B, the viewing angle control pixel Pb is adjacent to the three sub display pixels Pc in a direction orthogonal to one direction that is the arrangement direction of the three sub display pixels Pc constituting the display pixel Pa. May be arranged. In this way, by arranging the viewing angle control pixel Pb for each of the plurality of sub display pixels Pc, it is possible to reduce the contrast when viewed from the oblique direction for each sub display pixel Pc. Therefore, the viewing angle control performance by the viewing angle control pixel Pb is improved.

  Further, the present invention is not limited to this configuration. In the present invention, one viewing angle control pixel Pb may be provided for a plurality (at least one or more) of display pixels Pa. FIG. 14A shows a configuration example in which one viewing angle control pixel Pb is provided for two display pixels Pa. In this configuration example, the display pixels Pa constituting the R, G, and B sub display pixels Pc are arranged in a square shape. One viewing angle control pixel Pb is arranged at a position adjacent to one display pixel Pa in one direction among two display pixels Pa adjacent to each other in one direction. FIG. 14B shows another configuration example in which one viewing angle control pixel Pb is provided for two display pixels Pa. In this configuration example, other display pixels Pa are arranged at positions adjacent to the R, G, and B sub-display pixels Pc in one direction. Then, one viewing angle control pixel Pb is arranged corresponding to a position adjacent to each other in the direction substantially orthogonal to the display pixel Pa and the other display pixel Pa adjacent to each other. According to these configurations, since the area of the display pixel Pa can be increased in the image display area V, the definition of the display image can be improved accordingly.

[Electronics]
Next, an example of an electronic device using the liquid crystal device 1 according to the embodiment of the present invention will be described with reference to FIG.

  FIG. 15A shows an electronic apparatus using any one of the liquid crystal devices including the liquid crystal devices 1, 1 s, 1 t, 1 u, and 1 x according to the present embodiment (hereinafter referred to as “liquid crystal device 1” as a representative). The front view which looked at the mobile telephone 800 which is an example from the display surface side is shown. FIG. 15B is a side view of the mobile phone 800 when the mobile phone 800 shown in FIG. 15A is viewed from the transmission / reception antenna 800f side (arrow Y1 direction). In the following, the thickness direction of the mobile phone 800 of the present invention is defined as the Z direction, and the vertical direction of the paper of the mobile phone 800 shown in FIG. 15A is defined as the ± Y direction. The left and right direction of the cellular phone 800 shown in (a) is defined as the ± X direction. Further, the direction Pdr of the polar angle [°] is defined as an angle direction shifted by ± θ in the horizontal direction of the paper with respect to the normal direction Z1 of the display unit 800b in the mobile phone 800.

  The mobile phone 800 is provided on the front side of the case 800g, and includes a plurality of operation buttons 800a for performing input operations such as mail, a display unit 800b for displaying images (display images) such as characters, figures, and photos. The earpiece 800c and the mouthpiece 800d, a function operation button 800e for performing various function settings, and a transmission / reception antenna 800f provided on one side of the case 800g are configured. The liquid crystal device 1 according to the present embodiment is accommodated at a position corresponding to the display unit 800b in the case 800g. For this reason, in the mobile phone 800, the user can display an image on the display unit 800b by operating the operation button 800a, the function operation button 800e, or the like.

  In particular, the mobile phone 800 of the present invention has a wide viewing angle display mode in which a display image can be viewed from any direction during normal use, and a display image including mail, photos, etc. when used outdoors or in public places. It is possible to selectively switch between a narrow viewing angle display mode that lowers the contrast and makes it difficult for people other than the user to see the displayed image. The viewing angle switching between the wide viewing angle display mode and the narrow viewing angle display mode is realized by the user operating the operation button 800a or the function operation button 800e.

  In the cellular phone 800, when the wide viewing angle display mode is selected by the user, the display unit 800b is viewed from the front direction Y2 (Z direction), which is the normal direction Z1, in FIG. However, even when the display unit 800b is viewed from the right oblique direction Y3 (+ polar angle direction Pdr) inclined by + θ [°] with respect to the display surface of the display unit 800b from the normal direction Z1, Even when the display unit 800b is viewed from the left oblique direction Y4 (-polar angle direction Pdr) inclined by −θ [°] with respect to the display surface of the display unit 800b from the normal direction Z1, the display image can be visually recognized. . On the other hand, when the narrow viewing angle display mode is selected by the user, when the display unit 800b is viewed from the normal direction Z1 in FIG. When viewing 800b from the right oblique direction Y3 (especially polar angle +40 [°] or more) and the left oblique direction Y4 (especially polar angle −40 [°] or less), the luminance of the viewing angle control region of the liquid crystal device 1 Changes, and the contrast of the image decreases, so that the display image cannot be visually recognized.

  In the above-described embodiment, the mobile phone 800 is described as an example of an electronic device to which the liquid crystal device 1 of the present invention can be applied. However, the present invention is not limited to this, and the electronic device to which the liquid crystal device 1 of the present invention can be applied. In addition, portable personal computers (so-called notebook computers), LCD TVs, viewfinder / monitor direct-view video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, videophones POS terminals, digital still cameras, and the like.

1 is a perspective view illustrating a schematic configuration of a liquid crystal device according to an embodiment of the present invention. FIG. 3 is an equivalent circuit diagram illustrating an electrical configuration of the liquid crystal device according to the embodiment. The top view which shows the structure of a sub display pixel and a viewing angle control pixel. FIG. 4 is an essential part cross-sectional view of the liquid crystal device taken along a cutting line A-A ′ in FIG. FIG. 4 is an essential part cross-sectional view of the liquid crystal device taken along a cutting line B-B ′ in FIG. 3. The graph which shows the viewing angle characteristic of the transmittance | permeability of a sub display pixel and a viewing angle control pixel, and the graph which shows the viewing angle characteristic of the contrast in each of the presence or absence of viewing angle control. The graph which shows the relationship between the brightness | luminance of an oblique direction, and retardation at the time of changing the drive voltage of a viewing angle control pixel, and the graph which shows the relationship between the drive voltage and retardation. FIG. 4 is a cross-sectional view of a main part of a liquid crystal device according to another modification corresponding to FIG. 3. FIG. 4 is a cross-sectional view of a main part of a liquid crystal device according to another modification corresponding to FIG. 3. FIG. 4 is a cross-sectional view of a main part of a liquid crystal device according to another modification corresponding to FIG. 3. The visual angle control equivalent circuit schematic concerning the modification of this invention is shown. In a navigation system mounted on a vehicle, a configuration example is shown in which an image display area is divided into a plurality of display areas, and different viewing angle control is performed for each of the divided display areas. The top view which shows the other arrangement | sequence state of a sub display pixel and a viewing angle control pixel. The top view which shows the other arrangement | sequence state of a sub display pixel and a viewing angle control pixel. The front view and one side view which show the structure of the mobile telephone which concerns on embodiment of this invention.

Explanation of symbols

  1, 1s, 1t, 1u, 1x liquid crystal device, 11 element substrate, 12, 12s, 12t, 12u counter substrate, 13 liquid crystal layer, 13a liquid crystal molecule, 21, 22 pixel electrode, 21b, 22b strip, 39 common electrode, 45, 46 Overcoat layer (liquid crystal layer thickness adjusting layer), 600 viewing angle control equivalent circuit, 700 vehicle, 710 navigation system, 800 mobile phone, Pa display pixel (display pixel region), Pb viewing angle control pixel (viewing angle control pixel region) , Pc Sub display pixel (sub display pixel area)

Claims (6)

A liquid crystal device having a liquid crystal layer sandwiched between a pair of substrates,
In the plane region of the pair of substrates, at least one display pixel region and dark display in the front direction of the pair of substrate surfaces and in the oblique direction in the oblique direction with respect to the normal direction of the pair of substrate surfaces And at least one viewing angle control pixel region whose luminance changes in response.
In one of the pair of substrates, the display pixel region has a pair of electrodes for driving the liquid crystal layer, and the viewing angle control pixel region also has a pair of electrodes for driving the liquid crystal layer,
The pair of electrodes in the viewing angle control pixel region and the pair of electrodes in the display pixel region are driven independently,
The liquid crystal device according to claim 1, wherein the retardation of the viewing angle control pixel region is larger than the retardation of the display pixel region. In the other of the pair of substrates, the display pixel region is provided with a color filter layer for color display having a certain thickness, and the viewing angle control pixel region is provided with the color filter layer. Not
The liquid crystal device according to claim 1, wherein a thickness of the liquid crystal layer in the viewing angle control pixel region is larger than a thickness of the liquid crystal layer in the display pixel region.   At least one of the pair of substrates includes a liquid crystal layer thickness adjusting layer that makes a thickness of the liquid crystal layer in the display pixel region smaller than a thickness of the liquid crystal layer in the viewing angle control pixel region. 3. The liquid crystal device according to 1 or 2.   4. The liquid crystal device according to claim 1, wherein the retardation of the viewing angle control pixel region is in a range of 0.45 to 0.65 [μm]. 5.   The liquid crystal device according to claim 1, wherein the pair of electrodes are disposed to face each other with a dielectric layer interposed therebetween.   An electronic apparatus comprising the liquid crystal device according to claim 1 as a display unit.

Images