JP4069879B2 - Liquid crystal display device and electronic device - Google Patents

Description

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

  As a liquid crystal display device, there is a transflective liquid crystal display device that uses external light in a bright place as in a reflective liquid crystal display device, and in a dark place, the display can be visually recognized by a backlight in the same manner as a transmissive liquid crystal display device. Proposed. In such a transflective liquid crystal display device, a liquid crystal layer is sandwiched between an upper substrate and a lower substrate, and a reflective film in which a window for light transmission is formed on a metal film such as aluminum is disposed below. There is known a liquid crystal display device that is provided on the inner surface of a substrate and has the reflective film function as a transflective plate. In this case, in the reflection mode, external light incident from the upper substrate side passes through the liquid crystal layer, is reflected by the reflective film on the inner surface of the lower substrate, and passes through the liquid crystal layer again and is emitted from the upper substrate side to contribute to display. To do. On the other hand, in the transmissive mode, light from the backlight incident from the lower substrate side passes through the liquid crystal layer from the window portion of the reflective film, and then is emitted from the upper substrate side to the outside to contribute to display. Accordingly, of the reflective film formation region, the region where the window is formed is the transmissive display region, and the other region is the reflective display region.

However, the conventional transflective liquid crystal display device has a problem that the viewing angle in transmissive display is narrow. This is because a transflective plate is provided on the inner surface of the liquid crystal cell so that parallax does not occur, and there is a limitation that reflection display must be performed with only one polarizing plate provided on the viewer side. This is because the degree of freedom in design is small. In order to solve this problem, Jisaki et al. Proposed a new liquid crystal display device using vertically aligned liquid crystal in Non-Patent Document 1 and Patent Document 2 below. The characteristics are the following three.
(1) Employs a “VA (Vertical Alignment) mode” in which a liquid crystal having a negative dielectric anisotropy is aligned perpendicularly to a substrate, and this is defeated by applying a voltage.
(2) A “multi-gap structure” is employed in which the liquid crystal layer thickness (cell gap) is different between the transmissive display area and the reflective display area (refer to, for example, Patent Document 1).
(3) The transmissive display area is a regular octagon, and a projection is provided at the center of the transmissive display area on the counter substrate so that the liquid crystal is tilted 360 degrees in all directions in this area. In other words, “alignment division structure” is adopted.
Japanese Patent Laid-Open No. 11-242226 JP 2002-350853 A "Development of transflective LCD for high contrast and wide viewing angle by using homeotropic alignment", M. Jisaki et al., Asia Display / IDW'01, p.133-136 (2001)

  The multi-gap structure as disclosed in Patent Document 1 is an effective means for aligning the electro-optical characteristics (transmittance-voltage characteristics and reflectivity-voltage characteristics) of the transmissive display area and the reflective display area. This is because light passes through the liquid crystal layer only once in the transmissive display region, whereas light passes through the liquid crystal layer twice in the reflective display region.

  By the way, the method of orientation division adopted by Jisaki et al. Is a very clever method using a step between a protrusion and a multi-gap. However, this method has two major problems. One is that the alignment control force due to the multi-gap step is weak. This is because, in the multi-gap step portion, the liquid crystal molecules are aligned in the oblique direction perpendicular to the inclination of the step portion, but the electric field applied to this is also in the direction perpendicular to the inclination, so that the liquid crystal is tilted in one direction. Because power weakens. Therefore, if the distance between the protrusion provided at the center of the transmissive display area and the multi-gap stepped portion is more than a certain distance, the liquid crystal molecules will not fall in a predetermined direction when a voltage is applied. There is a problem in that the aperture ratio must be reduced. The other is that the direction in which the liquid crystal falls in the reflective display area is not sufficiently controlled. When the liquid crystal is tilted in a disordered direction, disclination appears at the boundary between different liquid crystal alignment regions, causing afterimages and the like. In addition, since each alignment region of the liquid crystal has different viewing angle characteristics, there may be a problem that when the liquid crystal device is viewed from an oblique direction, the liquid crystal device appears as rough uneven spots. Furthermore, sufficient reliability is not ensured in the electrical connection in the step part (inclined part) of the multi-gap, and there is a possibility of disconnection. In addition, since the appropriate electrode width and length are not provided in the step part (inclined part) of the multi-gap, in addition to the problem of the electrical connection reliability described above, the step part (inclined part) Electrodes that should originally be arranged in the display area (originally electrodes for driving the liquid crystal in the reflective display area and the transmissive display area) are allocated and arranged, and the liquid crystal is driven in both the reflective display area and the transmissive display area. There is a problem that the size (area) of the electrodes is not sufficiently secured, and the aperture ratio is lowered. Further, since the liquid crystal molecules are aligned along the inclined surface in the stepped portion (inclined portion), even if an electrode is provided in this boundary stepped region, an oblique electric field is generated when a voltage is applied, and the liquid crystal molecules are aligned. There is a risk that the liquid crystal alignment may not be sufficiently controlled, and it is difficult to obtain a good display as a display region.

  The present invention has been made to solve the above-described problems, and in a transflective liquid crystal display device, it is possible to suppress the occurrence of display defects such as afterimages and spotted unevenness in both transmissive display and reflective display. An object of the present invention is to provide a liquid crystal display device capable of realizing a bright and wide viewing angle display and sufficiently ensuring electrical connection reliability in a multi-gap step portion (inclined portion).

In order to solve the above problems, in the liquid crystal display device of the present invention, a liquid crystal layer is sandwiched between a pair of opposed substrates, and one of the pair of substrates is connected to a signal line and the signal line. And an electrode connected to the switching element and formed on the facing surface side, and the other substrate of the pair of substrates is provided with an electrode on the facing surface side. And a plurality of dot areas each formed by overlapping portions of the electrodes formed on the opposing surface side, and a transmissive display area for performing transmissive display and a reflective display area for performing reflective display in one dot area. And a liquid crystal display device in which the layer thickness of the liquid crystal layer in the reflective display region is set smaller than the layer thickness of the liquid crystal layer in the transmissive display region, formed on at least one of the pair of substrates The The electrode includes a plurality of island-shaped portions and a plurality of connecting portions that electrically connect the adjacent island-shaped portions to each other in the one dot region, and the one dot region The plurality of island-shaped portions are arranged in an integer number in each of the transmissive display region and the reflective display region, and the plurality of connecting portions are at least between the transmissive display region and the reflective display region adjacent to each other. And a connecting portion arranged in the stepped portion or the inclined portion, and the connecting portion arranged in the stepped portion or the inclined portion is wider than the width of the other connecting portions in the one dot region. It is formed.

  Furthermore, in the present invention, a plurality of the island-shaped portions are arranged in each of a predetermined direction and a direction intersecting with the predetermined direction in the dot region.

  That is, the liquid crystal display device of the present invention is a transflective, vertical alignment mode liquid crystal display device having a multi-gap structure, and an electrode in a dot region includes a plurality of island-shaped portions and the plurality of island-shaped portions. And a connecting part for electrically connecting the parts.

  In this way, the electrode in the dot region has a plurality of island-shaped portions. For example, when a liquid crystal having a negative dielectric anisotropy is used for the liquid crystal layer, the sides of the island-shaped portions are The tilted electric field generated at the edge causes the tilt direction of the vertically aligned liquid crystal to be regulated toward the center of the island portion, and as a result, a liquid crystal domain having a radial alignment state is formed in the planar region of each island portion. The By forming a plurality of liquid crystal domains having a planar radial alignment state in the dot region in this way, uniform viewing angle characteristics can be obtained in each direction by each liquid crystal domain, and the boundary between the liquid crystal domains is adjacent islands. Since it is fixed to the boundary region of the shape portion, good display can be obtained without causing spot-like unevenness when the panel is perspective.

  In such a configuration, a stepped portion or an inclined portion exists at the boundary portion between the reflective display region and the transmissive display region of the multi-gap structure because the thicknesses of the liquid crystal layers in both regions are different. Electrodes are formed to drive the liquid crystal in both the reflective display area and the transmissive display area. When the connecting portion is disposed at the stepped portion or the inclined portion, the island-shaped portion is electrically connected. Since the width of the connecting portion to be connected is formed thicker than the thickness of the connecting portion disposed elsewhere, the electrical connection is strengthened, so that it is possible to prevent display failure due to disconnection, connection failure, etc. .

In the case where a plurality of island-like portions are arranged as sub-pixels in one dot area in each of a predetermined direction and a direction intersecting the predetermined direction (for example, a vertical direction and a horizontal direction). In the high-quality display, the liquid crystal layer thickness is uniform within the island-shaped portion formation region arranged in each region, and the alignment state of the liquid crystal is appropriately controlled in both the reflective display and the transmissive display. Since the thickness of the appropriate connecting portion is set in the stepped portion or inclined portion of the multi-gap structure, the connection resistance between the sub-pixels (island-like portions) is reduced. Can do.

  As described above, according to the liquid crystal display device of the present invention, it is possible to obtain a display with a wide viewing angle and a high contrast in both the reflective display and the transmissive display, and high quality that does not cause stain-like unevenness when the panel is oblique. Can be obtained.

  Moreover, the said structure WHEREIN: The said island-shaped part can be set as the structure currently formed in the planar view substantially the same shape in each area | region of the said reflective display area | region and a transmissive display area | region. According to this configuration, since the shape and size of the liquid crystal domain formed in the dot region can be made uniform in both the reflective display region and the transmissive display region, the viewing angle characteristics of the reflective display and the transmissive display are uniform. Therefore, a display with uniform viewing angle characteristics can be obtained regardless of the switching of the display mode.

  In addition, when the liquid crystal layer is a liquid crystal having a negative dielectric anisotropy and the initial alignment state exhibits a vertical alignment, the alignment of the liquid crystal when an electric field is applied is in the plane region of the island-shaped portion. It is preferable that an orientation control means for controlling the state is provided. According to this configuration, by the alignment control action by the oblique electric field generated at the edge of the island-shaped part and the alignment control function by the alignment control means, the island-shaped part in the plane area (that is, in the display area) can be further improved. It becomes possible to control the alignment state of the liquid crystal, and even when the plane area of the island-shaped portion is relatively large, the alignment is hardly disturbed and a good display can be obtained.

  Moreover, it is preferable that the said orientation control means is provided in the approximate center part of the planar area | region of the said island-shaped part. According to this configuration, in the liquid crystal domain formed in the island-shaped portion formation region, it becomes possible to align the liquid crystal in a radial manner symmetrical with respect to the center of the island-shaped portion, and the viewing angle characteristics of the liquid crystal display device can be improved. It can be made symmetrical with respect to the panel front (substrate normal direction).

  In the liquid crystal display device of the present invention, the orientation control means is an opening provided in an electrode facing the island-like part through the liquid crystal layer, or a protrusion made of an insulating material provided on the electrode. It can be configured. In the liquid crystal display device according to the present invention, these openings and protrusions can be used as the alignment control means, and the tilt direction of the vertically aligned liquid crystal when applying voltage is good regardless of which configuration is applied. It is possible to control.

  In the liquid crystal display device of the present invention, it is preferable that the island-shaped portion has a substantially circular shape or a substantially regular polygonal shape in plan view. In the present invention, the island-shaped portion is provided in order to obtain a radial liquid crystal alignment in the same plane region by an oblique electric field generated at the side edge. Therefore, by applying each of the above shapes, a liquid crystal domain having the radial alignment state can be easily formed. From the viewpoint of uniform viewing angle characteristics, the island-like portion preferably has a shape having rotational symmetry with respect to the center of the surface, and preferably has a circular or regular polygonal planar shape.

  In the liquid crystal display device of the present invention, the plurality of island-shaped portions are configured by an island-shaped portion made of a reflective film and an island-shaped portion made of a transparent electrode.

  In the liquid crystal display device of the present invention, a reflective film is provided in the dot area partially and in an island shape including the reflective display area.

  In the liquid crystal display device of the present invention, the dot area includes a reflective film partially provided including the reflective display area, and the reflective film covers the dot area excluding the transmissive display area. It can be set as the formed structure. With such a configuration, the reflective film provided in an area other than the reflective display area can function as a light-shielding film, effectively blocking light leakage outside the transmissive display area, and the contrast of the transmissive display. Can be improved.

  In the liquid crystal display device according to the aspect of the invention, it is preferable that the reflective film is provided in a dot region excluding a planar region of an island-like portion disposed in the transmissive display region. The region of the connecting portion that connects the island-shaped portions can also be configured to be shielded by the reflective film, and in particular, the reflective film is provided in the region of the connecting portion that is arranged to overlap the boundary step region. By providing, leakage light in the boundary step region where liquid crystal alignment disorder is likely to occur can be blocked, and the contrast can be improved.

  In the liquid crystal display device of the present invention, a reflective film is provided in the dot area partially and in an island shape including the reflective display area.

  In the liquid crystal display device of the present invention, the island-shaped portion disposed in the reflective display region may have a larger plane area than the island-shaped portion disposed in the transmissive display region. As described above, in the liquid crystal display device of the present invention having a multi-gap structure, the alignment regulating action due to the island-shaped side edges in the reflective display area is greater than the alignment regulating action in the transmissive display area. Therefore, even if the island-shaped portion of the reflective display region is formed larger than the island-shaped portion of the transmissive display region, an equivalent orientation regulating action can be obtained. Thereby, when adjusting the reflective display, the transmissive display, and the luminance balance according to the purpose of use, it is possible to adjust by the plane area of the island-shaped portions in the two regions.

In the liquid crystal display device of the present invention, a signal wiring for supplying an electric signal to the electrode of the dot region extends to a side edge (between adjacent dot regions) of the dot region, and the transmission The island-shaped portion disposed in the display area may be configured to be separated from the signal wiring in a plane as compared with the island-shaped portion disposed in the reflective display area.
In the vicinity of the signal wiring, an unnecessary oblique electric field is generated by the potential, and the alignment of the liquid crystal may be disturbed. For this reason, it is preferable to arrange the signal wiring and the island-shaped part apart from each other to some extent, but there is a problem that the aperture ratio of the dot region decreases when the distance between the two is increased. Therefore, in this configuration, the island-shaped portion is separated from the signal wiring by a larger distance in the transmissive display region where the alignment regulation force at the edge of the island-shaped portion is weaker than that of the reflective display region and is easily affected by the electric field due to the signal wiring. Decided to place. As a result, the distance between the signal wiring and the island-shaped portion can be optimized in both the reflective display area and the transmissive display area, and the display quality due to the disorder of the alignment due to the oblique electric field generated in the vicinity of the signal wiring is improved. An optimum aperture ratio can be obtained in both the reflective display area and the transmissive display area while suppressing the decrease.

  The liquid crystal display device of the present invention includes a switching element electrically connected to the electrode having the island-shaped part and the connecting part, and the reflection film extends to a region where the switching element is formed. be able to. According to this configuration, even if the liquid crystal alignment is disturbed near the element due to the electric field of the switching element, the reflective film functions as a light shielding means, and light leakage can be prevented. Thereby, a high-contrast display can be obtained.

  Next, an electronic apparatus according to the present invention includes the liquid crystal display device according to the present invention described above. According to such a configuration, it is possible to provide an electronic apparatus including a display unit that can display in both the transmission mode and the reflection mode, and can display a wide viewing angle and high contrast in each display mode.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the drawings referred to below, the scale of each member is appropriately changed and displayed in order to make the laminated film and the member recognizable on the drawing.

(First embodiment)
FIG. 1 is a circuit configuration diagram of a liquid crystal display device according to a first embodiment of the present invention, FIG. 2 is a plan configuration diagram showing one pixel region, and FIG. 3 is an enlarged view of the pixel region. It is a plane block diagram (a figure), and a cross-sectional block diagram (b figure). The liquid crystal display device shown in these figures is an active matrix color liquid crystal display device using a TFD (Thin film diode) element (two-terminal nonlinear element) as a switching element. Further, the liquid crystal display device according to the present embodiment includes a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy in which the initial alignment is vertical alignment.

  The liquid crystal display device of this embodiment includes a scanning signal driving circuit 110 and a data signal driving circuit 120 as shown in FIG. The liquid crystal display device 100 is provided with signal lines, that is, a plurality of scanning lines 13 and a plurality of data lines 9 intersecting with these scanning lines 13. The scanning lines 13 are scanned by the scanning signal driving circuit 110. Are driven by the data signal driving circuit 120. In each pixel region 150, the TFD element 40 and the liquid crystal display element 160 (liquid crystal layer) are connected in series between the scanning line 13 and the data line 9. In FIG. 1, the TFD element 40 is connected to the scanning line 13 side and the liquid crystal display element 160 is connected to the data line 9 side. On the contrary, the TFD element 40 is connected to the data line 9 side and the liquid crystal display element 160 is connected to the data line 9 side. The display element 160 may be provided on the scanning line 13 side.

  Next, the planar structure of the electrodes provided in the liquid crystal display device of the present embodiment will be described with reference to FIG. As shown in FIG. 2, in the liquid crystal display device according to the present embodiment, pixel electrodes 31 connected to the scanning lines 13 via the TFD elements 40 are arranged in a matrix, and these pixel electrodes 31 are perpendicular to the paper surface. The common electrodes 9 are arranged in a strip shape (stripe shape) in plan view, facing the direction. The common electrode 9 forms a data line shown in FIG. 1 and has a stripe shape that intersects the scanning line 13. In the present embodiment, each region in which each pixel electrode 31 is formed constitutes one dot region, and the display can be performed for each dot region arranged in a matrix.

Here, the TFD element 40 is a switching element that electrically connects the scanning line 13 and the pixel electrode 31. The TFD element 40 is formed, for example, on the surface of the first conductive film mainly composed of Ta, the first conductive film, the insulating film mainly composed of Ta ₂ O ₃ , and the surface of the insulating film. An MIM structure including a second conductive film containing Cr as a main component is provided. The first conductive film of the TFD element 40 is connected to the scanning line 13, and the second conductive film is connected to the pixel electrode 31. Here, the pixel electrode 31 and the TFD element 40 which is a switching element are electrically connected via a contact hole 60 having an opening in the insulating film 26.

  Next, the pixel configuration of the liquid crystal display device 100 of the present embodiment will be described with reference to FIG. 3A is a plan configuration diagram illustrating one pixel region of the liquid crystal display device 100, and FIG. 3B is a cross-sectional configuration diagram along line A-A 'of FIG. As shown in FIG. 2, the liquid crystal display device 100 according to the present embodiment has a dot region including a pixel electrode 31 inside a region surrounded by the data lines 9 and the scanning lines 13. In this dot area, a color filter of one of the three primary colors is formed corresponding to one dot area as shown in FIG. 3A, and three dot areas (D1, D2, D3) Pixels including color filters 22R, 22G, and 22B are formed.

As shown in FIG. 3A, the pixel electrode 31 includes three island portions 31 a to 31 c and connecting portions 31 d and 31 e that electrically connect adjacent island portions. Yes. More specifically, the island-shaped portions 31a to 31c having a regular octagonal shape in plan view are arranged in the extending direction of the scanning line 13 extending along the edge of the dot region, and between the island-shaped portions 31a and 31b, The connecting portions 31d and 31e extending substantially parallel to the scanning line 13 are provided between the island-shaped portions 31b and 31c. And the island-shaped part 31a and the TFD element 40 are electrically connected.
The island portions 31a are arranged in the formation region of the reflection film 20 provided partially in each dot region, and the remaining island portions 31b and 31c are arranged in the non-formation region of the reflection film 20. Yes. A planar region of the island-shaped portion 31a (and a part of the connecting portion 31d) arranged in the formation region of the reflective film 20 is a reflective display region R in the present liquid crystal display device 100, and the island-shaped portions 31b, 31c, connected A part of the part 31d and the planar area of the connecting part 31e are a transmissive display area T. Then, the thickness of the width _{W 1} of the connecting portion 31d that connects the island-shaped portion 31a and the island-shaped portion 31b is thicker than the thickness of the width _{W 2} of the connecting portion 31e that connects the island portion 31c and the island shaped portion 31b formed Has been.

On the other hand, as shown in FIG. 3B, the liquid crystal display device 100 according to the present embodiment has an initial alignment between an upper substrate (element substrate) 25 and a lower substrate (counter substrate) 10 disposed opposite thereto. A liquid crystal layer 50 made of a liquid crystal material whose state is vertical alignment, that is, a liquid crystal material having negative dielectric anisotropy, is sandwiched. A backlight (illumination device) 15 that is a light source for transmissive display is provided outside the lower substrate 10.
As described above, the liquid crystal display device according to the present embodiment is a vertical alignment type liquid crystal display device including the vertical alignment type liquid crystal layer 50 and is a transflective liquid crystal display device capable of reflective display and transmissive display. is there.

In the lower substrate 10, a reflective film 20 made of a highly reflective metal film such as aluminum or silver is partially formed on the surface of a substrate body 10 </ b> A made of a translucent material such as quartz or glass via an insulating film 24. ing. A reflective display region R is provided in a region where the reflective film 20 is formed.
The insulating film 24 formed on the substrate body 10A has an uneven shape on its surface, and the surface of the reflective film 20 has an uneven portion following the uneven shape. Since the reflected light is scattered by such unevenness, reflection from the outside is prevented and good visibility can be obtained.

A red color filter 22R is provided across the reflective display region R and the transmissive display region T on the reflective film 20 in the dot region and on the substrate body 10A. In plan view, as shown in FIG. 3A, three color filters 22R (red), 22G (green), and 22B (blue) are arranged, and are planar with the boundary region of adjacent color filters. The scanning line 13 extends to overlap the.
On the upper substrate 25A, an insulating film 26 is selectively formed corresponding to the planar position (region) of the reflective display region R. Thus, the insulating film 26 partially formed in the dot region makes the layer thickness of the liquid crystal layer 50 different between the reflective display region R and the transmissive display region T. That is, the formation region of the insulating film 26 shown in FIG. 3A is formed in a region including the reflective display region R and is formed to be thinner than the liquid crystal layer 50 in the transmissive display region. ing. The insulating film 26 is made of an organic material film such as acrylic resin having a film thickness of about 0.5 to 2.5 μm, for example, and has a continuous film thickness in the vicinity of the boundary between the reflective display region R and the transmissive display region T. A boundary step region N (stepped portion or inclined portion) composed of an inclined surface that changes to is formed. The thickness of the liquid crystal layer 50 in the transmissive display region T is about 2 to 7 μm, and the thickness of the liquid crystal layer in the reflective display region R is about half of the thickness of the liquid crystal layer in the transmissive display region T. In the configuration of FIG. 3B, the insulating film 26 is not formed in the transmissive display region T, but the liquid crystal layer 50 in the reflective display region R and the transmissive display region T may have different thicknesses. An insulating layer having a thickness smaller than that corresponding to the reflective display region R may be formed in the transmissive display region T. 3A, the insulating film 26 is formed not only on the reflective display region R but also on the signal line (scanning line 31) along the signal line (scanning line 31). This also has an effect of shielding the influence of the electric field generated from the signal line (scanning line 31), that is, the electric field from the signal line (scanning line 31) that adversely affects the alignment control of the liquid crystal layer 50 exhibiting vertical alignment.

As described above, the insulating film 26 functions as a liquid crystal layer thickness adjusting layer that varies the thickness of the liquid crystal layer 50 between the reflective display region R and the transmissive display region T depending on its own film thickness. In the case of the present embodiment, the boundary step formed by the insulating film 26 is arranged so that the edge of the island-shaped portion 31 a constituting the pixel electrode 31 substantially coincides with the flat surface above the insulating film 26. The region N is disposed at a position overlapping the connecting portion 31d between the island-shaped portions 31a and 31b in plan view. The length L ₁ of the connecting portion 31d that connects the island-shaped portions 31a and island portions 31b disposed in the boundary stepped area N (step portion or inclined portion), and the island-shaped portion 31c in the transmissive display area T Island of the connecting portion 31e that connects Jo portion 31b formed to be longer than the length L _2.

  In the lower substrate 10, a planarizing film is formed on the color filter 22R, and a common electrode 9 made of a transparent conductive material such as ITO is further formed. The common electrode 9 is formed in a stripe shape in plan view extending in the direction perpendicular to the paper surface, and functions as a common electrode for a plurality of dot regions arranged in parallel in the direction perpendicular to the paper surface. Further, the common electrode 9 is formed with openings 9a to 9c having a shape corresponding to each dot region by cutting out a part thereof. As shown in FIG. 3A, the openings 9a to 9c are provided corresponding to the island portions 31a to 31c of the pixel electrode 31, respectively, and are substantially at the center of the planar areas of the island portions 31a to 31c. It is arranged in the part.

  Although not shown, a vertical alignment film made of polyimide or the like is formed so as to cover the common electrode 9. This vertical alignment film is an alignment film that aligns liquid crystal molecules perpendicularly to the film surface. In this embodiment, it is preferable to use a film that has not been subjected to alignment treatment such as rubbing.

  On the upper substrate 25 side, the liquid crystal layer 50 side of the substrate body 25A made of a translucent material such as glass or quartz is made of a transparent conductive material such as ITO and has a planar shape shown in FIG. A pixel electrode 31 is formed, and a TFD element 40 provided corresponding to the pixel electrode 31 and the scanning line 13 are provided. Although not shown, a vertical alignment film made of polyimide or the like is provided so as to cover the pixel electrode 31.

A circularly polarizing plate is provided on the outer surface side of the lower substrate 10 by laminating a retardation plate 18 and a polarizing plate 19 from the substrate body 10A side. The outer surface side of the upper substrate 25 is positioned from the substrate body 25A side. A circularly polarizing plate in which the phase difference plate 16 and the polarizing plate 17 are laminated is provided. That is, in the liquid crystal display device 100 according to the present embodiment, display is performed by making circularly polarized light incident on the liquid crystal layer 50. By adopting such a configuration, the transmittance in the dot region does not become non-uniform depending on the orientation direction of the liquid crystal molecules at the time of voltage application as in the case where linearly polarized light is incident on the liquid crystal layer 50. It is possible to substantially improve the aperture ratio of the dot region, thereby improving the display brightness of the liquid crystal display device.
As the configuration of the circular polarizing plate, a circular polarizing plate combining a polarizing plate and a λ / 4 retardation plate, a broadband circular polarizing plate combining a polarizing plate, a λ / 2 retardation plate, and a λ / 4 retardation plate, Alternatively, a circularly polarizing plate having a viewing angle compensation function in combination with a polarizing plate, a λ / 2 retardation plate, a λ / 4 retardation plate, and a negative C plate (an optical compensation plate having negative uniaxiality in the film thickness direction) Can be adopted. The “C plate” is a retardation plate having an optical axis in the film thickness direction.

  In the liquid crystal display device of the present embodiment having the above-described configuration, the pixel electrode 31 is configured such that the regular octagonal island-shaped portions 31a to 31c are electrically connected by the connecting portions 31d and 31e, and the island-shaped portion 31a. Since the openings 9a to 9c are provided in the common electrode 9 corresponding to each of .about.31c, the tilt direction of the liquid crystal molecules at the time of applying an electric field is appropriately controlled, and the display has excellent viewing angle characteristics. It can be carried out. This orientation control action will be described below.

First, in a state where no electric field is applied between the common electrode 9 and the pixel electrode 31 (when no voltage is applied), the liquid crystal molecules of the liquid crystal layer 50 are aligned perpendicular to the substrate surface. When a voltage is applied to the electrodes 9 and 31, the liquid crystal molecules arranged in the planar region of the island-shaped portion 31a are perpendicular to the side edges of the island-shaped portion 31a in the plane direction due to the oblique electric field generated at the side edge portions. The liquid crystal molecules around it fall in the same direction so as to be aligned with the alignment state at the side edge of the island 31a. As a result, the liquid crystal molecules arranged in the planar region of the island-shaped part 31a are oriented toward the center of the regular octagonal island-shaped part 31a when an electric field is applied.
Further, in the case of the present embodiment, the planar circular opening 9a is provided at substantially the center of the planar region of the island-shaped portion 31a, so that the side of the island-shaped portion 31a is also provided on the common electrode 9 side. The alignment control action similar to that of the end portion occurs, and the liquid crystal molecules are aligned radially in plan view with the opening 9a as the center.

As described above, in the liquid crystal display device 100 of the present embodiment, when a voltage is applied, a flat electric field is generated in the plane region of the island portion 31a by the oblique electric field generated at the peripheral end portion of the island portion 31a and the peripheral end portion of the opening 9a. A liquid crystal domain in which liquid crystal molecules are aligned radially is formed. Also in the planar regions of the island-shaped portions 31b and 31c, a planar liquid crystal domain is generated by the same orientation control action as the island-shaped portion 31a.
With the above operation, the liquid crystal display device 100 according to the present embodiment has a structure in which liquid crystal domains having a radial alignment state in a plan view are arranged in the dot regions D1 to D3 when a voltage is applied. On the other hand, a uniform viewing angle characteristic is obtained, and the disclination generated in the central portion of the liquid crystal domain is fixed at the position of the island-shaped portions 31a to 31c. There will be no unevenness. Therefore, in the liquid crystal display device 100 of this embodiment, a high-quality display can be obtained in a very wide viewing angle range.
In addition, as described above, each of the island-shaped portions is formed by the side edges of the island-shaped portions 31a to 31c and the openings 9a to 9c of the common electrode 9 provided corresponding to the island-shaped portions 31a to 31c. Since the alignment state of the liquid crystal in the region is controlled, the alignment state of the liquid crystal can be controlled well even when the plane area of the island portions 31a to 31c formed in the dot region is increased. It is like that. Specifically, according to the configuration of the present embodiment, even if relatively large island portions 31a to 31c of about 40 to 50 μmφ are formed, the orientation can be stabilized.

In the present embodiment, the planar shape of the island-shaped portions 31a to 31c is a regular octagonal shape, but the planar shape of the island-shaped portions 31a to 31c is not limited to such a shape, for example, a circular shape, an elliptical shape, or a polygonal shape. Any of these can be applied. That is, the island-shaped portions 31a to 31c can be applied without any problem as long as they can form liquid crystal domains that take a substantially radial alignment state when a voltage is applied in the plane region.
The connecting portions 31d and 31e are preferably formed as thin as possible with respect to the island portions 31a to 31c. Since the island-shaped portions 31a to 31c have a function of controlling the tilt direction of the liquid crystal molecules by an oblique electric field generated at their side edges, the connection portions 31d and 31e are thinned in order to stably obtain the alignment regulating force. Thus, it is preferable to increase the ratio of the side edges that surround the center of the surface of the island-shaped portion. In addition, such a configuration also has the effect of improving the response speed of the liquid crystal.

  In the liquid crystal display device 100 of this embodiment, the insulating film 26 provided in the reflective display region R can reduce the thickness of the liquid crystal layer 50 in the reflective display region R to about half of the liquid crystal layer thickness in the transmissive display region T. Therefore, the retardation of the liquid crystal layer in the reflective display region R and the retardation of the liquid crystal layer in the transmissive display region T can be made substantially equal. As a result, the electro-optical characteristics in both the regions can be made uniform, and the display contrast can be improved.

  Further, by adopting the multi-gap structure, the boundary step region N generated in the dot region extends to a region between the island-shaped portion 31a of the reflective display region R and the island-shaped portion 31b of the transmissive display region T. The deterioration of quality can be effectively suppressed in the connecting portion. That is, when the electrode is formed in the boundary step region N, the liquid crystal molecules are inclined and aligned with respect to the substrate surface, so that a weak alignment regulating force acts on the liquid crystal molecules when a voltage is applied. If the pixel structure is designed ignoring this weak alignment regulating force, the liquid crystal alignment may be disturbed. Jisaki et al. Of Non-Patent Document 1 introduced earlier performed the orientation control by actively utilizing this weak orientation regulating force. In the liquid crystal display device according to the present embodiment, an electrode disposed on the boundary step region N is removed as much as possible to remove this weak alignment regulating force, and conversely, an oblique electric field generated at the edges of the island portions 31a and 31b. By making the strong orientation regulating force due to the above, dominant display can be obtained in both the reflective display region R and the transmissive display region T.

  In the above embodiment, as the orientation control means, substantially circular openings 9 a to 9 c are provided in the common electrode 9. However, as the orientation control means, a dielectric protrusion is provided on the common electrode 9. The formed configuration can also be applied. Even in this case, although the action is different from that of the openings 9a to 9c, an effect of controlling the tilt direction of the liquid crystal molecules when an electric field is applied can be obtained. Alternatively, the opening and the dielectric protrusion may be mixed in the dot region. In general, if the plane area is the same, the dielectric protrusion has a larger alignment regulating force than the opening, and therefore, for example, an opening is provided in the reflective display region R having a thin liquid crystal layer thickness, and the transmissive display region T having a large liquid crystal layer thickness. A structure in which a dielectric protrusion is provided is preferable. Furthermore, dielectric protrusions may be provided inside the openings 9a to 9c.

  As described above, the liquid crystal display device according to the present embodiment tilts the liquid crystal molecules in the liquid crystal layer in the vertical alignment mode by the shape of the pixel electrode 31 on the upper substrate 25 side and the openings 9 a to 9 c provided in the common electrode 9. It is possible to provide a structure for appropriately controlling the direction and to effectively prevent deterioration of display quality due to the boundary step region N caused by the multi-gap structure. There is no problem in display quality, and a wide viewing angle, high contrast reflective display and transmissive display can be obtained.

  Moreover, it is good also as a structure as shown to Fig.4 (a) and (b). FIG. 4A is a diagram illustrating a planar structure of the pixel region on the upper substrate 25, and FIG. 4B is a diagram illustrating a planar structure of the pixel region on the lower substrate 10.

  In the present embodiment, the reflective film 20 is also provided in the planar region of the connecting portion 31d and the planar region of 31e arranged in the boundary step region N. Since the connection portion 31d is shielded by the reflective film 20, the display defect portion caused by the alignment disorder in the connection portion 31d overlapping the boundary step region N can be shielded, and a high contrast display can be obtained. This is also advantageous in terms of the ease of patterning of the reflective film 20.

  Since the liquid crystal display device according to the present invention is a vertical alignment mode liquid crystal display device, when a voltage non-application state is black display (normally black), electrodes facing each other with a liquid crystal layer interposed therebetween are provided. Since the liquid crystal molecules maintain a state of being vertically aligned with respect to the substrate without depending on the voltage application state, the reflective film 20 that functions as a light shielding film is not necessary. However, in reality, the liquid crystal molecules are inclined in the boundary step region N, the oblique electric field at the side edges of the islands 31a to 31c, or the accumulation of electric charges in the region where no electrode is formed. Disturbance and light leakage may occur. Therefore, by providing the reflection film 20 functioning as a light shielding film in the non-display area as in the present embodiment, it is possible to block these light leaks and obtain a high contrast transmission display.

  As described above, the liquid crystal display device according to the present embodiment is a transflective liquid crystal display device that suppresses the occurrence of display defects such as afterimages and spotted unevenness in both the transmissive display and the reflective display, and is bright and has a wide viewing angle. An object of the present invention is to provide a liquid crystal display device capable of realizing display, and sufficiently ensure electrical connection reliability in a multi-gap step portion (inclined portion).

(Second Embodiment)
Next, a liquid crystal display device according to a second embodiment will be described with reference to the drawings. FIG. 5A is a diagram illustrating a planar structure of an enlarged pixel region in the liquid crystal display device of the present embodiment, and FIG. 5B is a cross-sectional structure diagram. 5 (a) and 5 (b), components having the same reference numerals as those shown in FIG. 3 are not described as similar components. In the first embodiment, the configuration in which the three island portions 31a to 31c are linearly arranged in each of the dot regions D1 to D3 has been described. However, the liquid crystal display device of the present embodiment has the pixel electrode 31. It is the structure which increased the number of the island-shaped parts which comprise. In the liquid crystal display device according to the present invention, the reflective display region and the transmissive display region are configured by an integer number of island-shaped portions, respectively, and the boundary step region N formed at the boundary between the regions having different liquid crystal layer thicknesses is the island-shaped portion. To be placed in between. In a configuration in which 3 × 3 (9) island-shaped portions are arranged in the dot area, three island-shaped portions are allocated to the reflective display area, and the remaining six island-shaped sections are allocated to the transmissive display area. . And the area | region between the island-like part arrange | positioned at the said reflective display area | region, the island-like part arrange | positioned at a transmissive display area | region, and the said boundary level | step difference area | region N are arrange | positioned so that it may planarly overlap. Further, the reflective film 20 is also used as a part of the pixel electrode 31 to serve as the island portion 31a. An insulating film 26 having a different thickness of the liquid crystal layer 50 in each of the reflective display region R and the transmissive display region T is formed on the lower substrate 10, and unevenness is given to the upper surface of the insulating film 26. The reflective film 20 is formed. The TFT element (not shown) that is a switching element and the pixel electrode 31 (the island portion 31a that is the reflective film 20) are electrically connected through a contact hole 60 that has an opening in the insulating film 26. Here, the electrical connection between the TFT element and the island-shaped portion of the pixel electrode disposed in the reflective display region R is any one of the island-shaped portions of the plurality of pixel electrodes disposed in the reflective display region R. What is necessary is just to be electrically connected with the island-shaped part. The TFT element is connected to a scanning line (gate line) 13 and a source line (not shown) to which an image signal is supplied.

  Further, the color filter 22 and the common electrode 9 are formed in this order on the surface of the upper substrate 22 on the liquid crystal layer 50 side, and the island portions 31a and 31b of the pixel electrode 31 formed on the lower substrate 10 are formed. , 31c, projections 9d, 9e, 9f made of a dielectric material are arranged in the form of dots. Each of these protrusions 9d, 9e, 9f is disposed at the approximate center (center) of each of the island portions 31a, 31b, 31c in a plan view.

In the pixel electrode 31, three island portions 31a and three connecting portions 31d arranged in the reflective display region R are formed of aluminum or a metal whose main component is silver, and six islands arranged in the transmissive display region T. The shape portions 31b and 31c are made of a transparent conductive material such as ITO. In the dot region, these island portions are electrically connected to the adjacent island portions in the vertical and horizontal directions via connecting portions. Therefore, the width W ₁ of the connecting portion 31d disposed in the boundary stepped area N (inclined portion or the stepped portion) of the connecting portion for electrically connecting the islands, from the width W ₂ of the other connection portion 31e Widely formed. Furthermore, Furthermore, the length L ₁ of the reflective display region R and the transmissive display since the stepped portion at the boundary region T is (or inclined portion) occurs (the inclined portion or the stepped portion) connecting portion 31d disposed in the other It formed to be longer than the length L ₂ of the connecting portion 31e. Therefore, since the length corresponding to the inclined portion (or stepped portion) is supplemented to the connecting portion 31d, the island-like portion 31a arranged in the reflective display region R and the island-like portion arranged in the transmissive display region T are provided. This ensures electrical connection with the island-shaped portion 31b that is disposed adjacent to the reflective display region side.

  In the embodiment of the present invention, the island-shaped portion 31a forming the reflective display region R has a shape different from the island-shaped portions 31b and 31c arranged in the transmissive display region T, or a different planar region (area). It may be formed. Further, the protrusions 9d to 9f provided on the common electrode 9 side corresponding to the island-shaped portions 31a to 31c are formed with the same planar shape size and height.

  Further, in the transflective liquid crystal display device, the required display characteristics may differ depending on the application of the mounted electronic device. In such a case, the display area of the reflective display region R and the transmissive display region T is adjusted by forming the island-shaped portion 33a of the reflective display region R relatively large or small so that the reflective display and the transmissive display can be performed. The display characteristics can be adjusted.

  In the reflective display region R, since the layer thickness of the liquid crystal layer 50 is relatively small due to the multi-gap structure, the alignment regulating force by the side edges of the island-shaped portion 31a is reduced by the island-shaped portions 31b, It becomes larger than 31c. Therefore, even when the planar area of the island portion 31a is made relatively large, the alignment state of the liquid crystal can be controlled well by the alignment regulating action by the edge of the island portion, and the response of the liquid crystal molecules is compared with that of the transmissive display area T. Therefore, high-quality display can be obtained without causing rough spot-like unevenness or image sticking.

  In addition, it is preferable that the size and / or height of the dielectric protrusions disposed in the reflective display region R be smaller than the size and / or height of the dielectric protrusions in the transmissive display region T.

  As described above, the technical scope of the present invention is not limited to the embodiments of the present invention, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the insulating film 26 for realizing the multi-gap structure is provided on the lower substrate 10 side. However, the structure in which the insulating film 26 is provided on the liquid crystal layer 50 side of the upper substrate 25 is also applicable. In addition, the thickness of the liquid crystal layer in the reflective display region can be adjusted by providing an insulating film at a position where the lower substrate 10 and the upper substrate 25 face each other.

  In the liquid crystal display device of each of the above embodiments, the liquid crystal layer 50 can be a vertically aligned liquid crystal to which a chiral agent is added. In this case, liquid crystal domains in which liquid crystal molecules are aligned in a spiral shape in plan view around the protrusions 9d to 9f are formed in the planar regions of the island portions 31a to 31c when a voltage is applied. By forming a liquid crystal domain in which liquid crystal molecules are arranged in a spiral manner in this way, even when linearly polarized light is incident on the liquid crystal layer 50 and display is performed, nonuniform luminance is hardly generated in the dot region. Thus, a bright display can be obtained.

  In the present embodiment, the electrical connection between the reflective film 20 (island portion 31a) disposed in the reflective display region R and the island portion 31b disposed in the transmissive display region T is connected to the boundary step region N ( An inclined portion or a stepped portion) is performed at the end, and an island-like portion made of a transparent electrode having the same shape as that of the transparent film 20 (island-like portion 31a) disposed in the reflective display region R is laminated. It is possible to make electrical connection. In this case, like the pixel electrode in the first embodiment, all island-like portions and connecting portions formed in the dot region are integrally formed with a pattern.

  As described above, the liquid crystal display device according to the present embodiment is a transflective liquid crystal display device that suppresses the occurrence of display defects such as afterimages and spotted unevenness in both transmissive display and reflective display, and is bright and has a wide viewing angle. An object of the present invention is to provide a liquid crystal display device capable of realizing display, and sufficiently ensure electrical connection reliability in a multi-gap step portion (inclined portion).

(Electronics)
FIG. 6 is a perspective view showing an example of an electronic apparatus according to the present invention. A cellular phone 1300 shown in this figure includes the display device of the present invention as a small-sized display portion 1301 and includes a plurality of operation buttons 1302, an earpiece 1303, and a mouthpiece 1304.
The display device of each of the above embodiments is not limited to the mobile phone, but is an electronic book, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type or a monitor direct view type video tape recorder, a car navigation device, a pager, and an electronic notebook. , Calculators, word processors, workstations, video phones, POS terminals, devices equipped with touch panels, etc., and can be suitably used as image display means. In any electronic device, it is bright, has high contrast, and has a wide viewing angle. Transmissive / reflective display is possible.

FIG. 1 is a circuit configuration diagram of a liquid crystal display device according to a first embodiment. FIG. 2 is an explanatory diagram showing the electrode configuration in a plan view. FIG. 3 is a plan configuration diagram (a diagram) and a sectional configuration diagram (b diagram) showing an enlarged pixel region. FIG. 4 is a plan configuration diagram (a diagram) showing an enlarged pixel region on the upper substrate 25, and a plan configuration diagram (b diagram) showing the pixel region on the lower substrate in an enlarged manner. FIG. 5 shows a pixel region of the liquid crystal display device of the second embodiment, and is a plan configuration diagram (a diagram) and a sectional configuration diagram (b diagram) showing the pixel region in an enlarged manner. FIG. 6 is a perspective configuration diagram illustrating an example of an electronic apparatus according to the invention.

Explanation of symbols

N: Boundary step region N (stepped portion or inclined portion), 9 ... Common electrode (data line), 13 ... Scanning line (signal wiring), 20 ... Reflecting film, 24 ... Insulating film (light scattering applying means), 26 ... Insulating film (liquid crystal layer thickness adjusting layer) 31... Pixel electrode 50... Liquid crystal layer R R reflective display area T transmissive display area 31 a, 31 b and 31 c. , 9b, 9c ... opening, 9d, 9e, 9f ... projection, 22 ... color filter, 60 ... contact hole.

Claims (10)

A liquid crystal layer is sandwiched between a pair of opposing substrates, and one of the pair of substrates has a signal line, a switching element connected to the signal line, and a facing surface connected to the switching element. Of the pair of substrates, the other substrate is provided with an electrode on the opposing surface side, and from the overlapping portion of the electrodes formed on the opposing surface side, respectively. A plurality of dot areas are formed, and a transmissive display area for performing transmissive display and a reflective display area for performing reflective display are provided in one dot area, and the thickness of the liquid crystal layer in the reflective display area Is a liquid crystal display device set smaller than the thickness of the liquid crystal layer in the transmissive display region,
The electrode formed on at least one of the pair of substrates has a plurality of island-shaped portions and a plurality of connecting portions that electrically connect the adjacent island-shaped portions to each other in one dot region. And
Within the one dot region, the plurality of island-like portions are arranged in an integer number in each of the transmissive display region and the reflective display region, and the plurality of connecting portions are at least reflective to the transmissive display region adjacent thereto. It has a connecting part arranged in a stepped part or an inclined part generated between the display area and
The liquid crystal display device, wherein the connecting portion arranged in the stepped portion or the inclined portion is formed wider than the width of the other connecting portion in the one dot region.   2. The liquid crystal display device according to claim 1, wherein a plurality of the island-shaped portions are arranged in each of a predetermined direction and a direction crossing the predetermined one direction in the dot region.   3. The liquid crystal display device according to claim 1, wherein the plurality of island-shaped portions includes an island-shaped portion made of a reflective film and an island-shaped portion made of a transparent electrode.   3. The liquid crystal display device according to claim 1, wherein a reflective film is provided partially and in an island shape including the reflective display region in the dot region.   In the dot area, a reflective film is provided including the reflective display area, and the reflective film is formed so as to cover the inside of the dot area except for the planar area of the island-shaped portion arranged in the transmissive display area. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a liquid crystal display device.   The liquid crystal layer is a liquid crystal having a negative dielectric anisotropy, and the initial alignment state exhibits a vertical alignment, and the alignment that controls the alignment state of the liquid crystal when an electric field is applied in the planar region of the island-shaped portion 6. The liquid crystal display device according to claim 1, further comprising a control unit.   The liquid crystal display device according to claim 6, wherein the orientation control unit is provided at a substantially central portion of a planar region of the island-shaped portion.   7. The alignment control means is an opening provided in an electrode facing the island-like portion through a liquid crystal layer, or a protrusion made of an insulating material provided on the electrode. Or a liquid crystal display device according to 7;   The liquid crystal display device according to claim 1, wherein the island-shaped portion has a substantially circular shape or a substantially regular polygonal shape in a plan view.   An electronic apparatus comprising the liquid crystal display device according to claim 1.

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