Source: https://patents.google.com/patent/JP3900123B2/en
Timestamp: 2020-02-18 11:15:41
Document Index: 501433125

Matched Legal Cases: ['art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'arts 32', 'arts 32', 'art 31', 'arts 31', 'art 33', 'art 33', 'art 33', 'art 34', 'art 34', 'art 34']

JP3900123B2 - Liquid crystal display device and electronic device - Google Patents
JP3900123B2
JP3900123B2 JP2003282775A JP2003282775A JP3900123B2 JP 3900123 B2 JP3900123 B2 JP 3900123B2 JP 2003282775 A JP2003282775 A JP 2003282775A JP 2003282775 A JP2003282775 A JP 2003282775A JP 3900123 B2 JP3900123 B2 JP 3900123B2
JP2003282775A
JP2005049687A (en
2003-07-30 Application filed by セイコーエプソン株式会社 filed Critical セイコーエプソン株式会社
2003-07-30 Priority to JP2003282775A priority Critical patent/JP3900123B2/en
2005-02-24 Publication of JP2005049687A publication Critical patent/JP2005049687A/en
2007-04-04 Publication of JP3900123B2 publication Critical patent/JP3900123B2/en
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.
(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.
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.
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 bright and wide viewing angle display.
In order to solve the above problems, the present invention comprises a pair of substrates having electrodes on one side, and a liquid crystal layer sandwiched between the pair of substrates via the electrodes, in one dot region, A transmissive display region for performing transmissive display and a reflective display region for performing reflective display are provided, and the liquid crystal layer includes a liquid crystal having negative dielectric anisotropy, and the liquid crystal layer thickness of the reflective display region is equal to that of the transmissive display region. A liquid crystal display device formed thinner than a liquid crystal layer thickness, wherein an adjustment layer for adjusting the liquid crystal layer thickness is provided on one of the pair of substrates in the dot region, and the one substrate The electrode provided on the substrate opposite to the substrate has a plurality of island portions and a connecting portion that electrically connects the adjacent island portions to each other, and the plurality of island portions An integer number is arranged in each of the display area and the reflective display area, Serial liquid crystal layer different boundary difference region thicknesses are provided between the transmissive display region arranged islands and the reflective display region arranged islands, the connecting portion is the boundary stepped region Provided is a liquid crystal display device which is arranged in a corresponding 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, so that the tilt direction of the vertically aligned liquid crystal moves toward the center of the island-shaped portion due to the oblique electric field generated at the edge of the island-shaped portion when voltage is applied. As a result, a liquid crystal domain having a radial alignment state is formed in the planar region of each island-like portion. 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.
Furthermore, in the present invention, since the above-mentioned island-shaped portions are arranged in an integer number in each of the reflective display region and the transmissive display region, in the formation region of the island-shaped portion disposed in each region, The liquid crystal layer thickness is uniform, and high-quality display in which the alignment state of the liquid crystal is appropriately controlled can be obtained in both reflective display and transmissive display.
Furthermore, a boundary step region (multi-gap step region) provided in the dot region so as to make the liquid crystal layer thickness different between the reflective display region and the transmissive display region is used to electrically connect adjacent island portions. Since it is arranged so as to overlap with the provided connecting portion in a plan view, it is possible to effectively suppress the deterioration in display quality due to the multi-gap structure. More specifically, since liquid crystal molecules are aligned along the inclined surface in the boundary step region, if an electrode is provided in the boundary step region, an oblique electric field is generated when a voltage is applied, and the alignment of the liquid crystal molecules is performed. May be disturbed. Therefore, in the present invention, the above configuration eliminates electrodes from the boundary step region as much as possible, and effectively prevents display quality deterioration due to the boundary step region.
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.
In the liquid crystal display device of the present invention, the island-shaped portion may be formed in the same shape in plan view in each of the reflective display area and the transmissive display area. 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 the liquid crystal display device of the present invention, it is preferable that alignment control means for controlling the alignment state of the liquid crystal when an electric field is applied is provided in the planar region of the island-shaped portion. 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.
In the liquid crystal display device of the present invention, it is preferable that the orientation control means is provided at a substantially central portion of the planar region of the island-shaped portion. 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 alignment control means is provided corresponding to each island-shaped portion in the dot region, and the alignment control means corresponding to the island-shaped portion disposed in the reflective display region is the transmission It can be configured to have a smaller planar area than the orientation control means of the display region.
In the liquid crystal display device of the present invention having a multi-gap structure, in the reflective display region in which the liquid crystal layer thickness is relatively thin, the oblique electric field at the edge of the island-shaped portion and the alignment regulating action by the alignment control means are the liquid crystal layer thickness. This is larger than a thick transmissive display area. Therefore, in this configuration, the plane area of the alignment control means in the reflective display area is made smaller than the alignment control means in the transmissive display area, and it is equivalent to the transmissive display area by utilizing the difference in the alignment regulating action due to the liquid crystal layer thickness. The effect of improving the aperture ratio by reducing the flat area and the like was obtained while obtaining the orientation regulating action. Therefore, according to this configuration, it is possible to improve the brightness without reducing the contrast of the reflective display.
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 circular shape or a 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, it is preferable that the planar shape of the electrode in the connection region between the island-shaped portion and the connecting portion is a tapered shape from the island-shaped portion side toward the connecting portion side. With such a configuration, in the connection region, liquid crystal molecules are aligned from both sides toward the connecting portion. Therefore, when disclination occurs in the vicinity of the connection region, the disclination occurs. Nation can be collected on the connecting portion side, and a good display can be obtained while minimizing the deterioration of display quality due to such disclination.
In the liquid crystal display device according to the aspect of the invention, it is preferable that the connecting portion is extended from a corner portion of the island-shaped portion or a side edge protruding outward in a plan view. With such a configuration, it is possible to obtain an effect of substantially increasing a margin for misalignment of the substrates sandwiching the liquid crystal layer. For example, when an electrode having the island-like portion and the connecting portion is provided on one substrate and a boundary step region by a multi-gap structure is formed on the other substrate, the connecting portion and the boundary step region are overlapped. The substrate is aligned accordingly. At this time, when the boundary step region and the island-shaped portion overlap due to the misalignment between the substrates, the display contrast is lowered due to the influence of the boundary step region. In this case, in this configuration, since the overlap between the island-shaped portion and the boundary step region can be reduced, it is possible to minimize display quality deterioration due to the misalignment.
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, 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 of the dot region, and the island-shaped portion arranged in the transmissive display region is Compared to the island-shaped portions arranged in the reflective display area, the signal wirings may be spaced apart in a plane.
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 can be improved. An optimum aperture ratio can be obtained in both the reflective display area and the transmissive display area while suppressing the decrease.
Next, in order to solve the above-described problem, the present invention includes a pair of substrates having electrodes on one surface side, and a liquid crystal layer sandwiched between the pair of substrates via the electrodes. A liquid crystal display device in which a transmissive display area for performing transmissive display and a reflective display area for performing reflective display are provided, wherein the liquid crystal layer includes liquid crystal having an initial alignment state of vertical alignment, and the transmissive display area And the reflective display region are formed to have different layer thicknesses, and at least one of the electrodes of the pair of substrates electrically connects the plurality of island-like portions and the adjacent island-like portions to each other in the dot region. A plurality of island-like portions arranged in each of the transmissive display area and the reflective display area, and the island-like parts arranged in the reflective display area, Larger than islands arranged in transparent display area To provide a liquid crystal display device characterized by having an area.
Similarly to the previous liquid crystal display device, the liquid crystal display device of this configuration is a transflective vertical alignment mode liquid crystal display device having a multi-gap structure, and the electrode in the dot region includes a plurality of island-shaped portions, And a connecting portion that electrically connects the plurality of island-shaped portions. In this way, by providing an electrode having a plurality of island-shaped portions in the dot region, the tilt direction of the vertically aligned liquid crystal is moved toward the center of the island-shaped portion by an oblique electric field generated at the edge of the island-shaped portion when a voltage is applied. As a result, a plurality of liquid crystal domains having a planar radial alignment state can be formed in the planar region of the island-shaped portion. As a result, uniform viewing angle characteristics in all directions can be obtained by each liquid crystal domain, and the liquid crystal domain boundary is fixed to the boundary region of the adjacent island-shaped portion, so that no stain-like unevenness occurs when the panel is perspectived. Good display can be obtained.
And in this structure, the island-like part arrange | positioned at a reflective display area is formed larger planarly than the island-like part arrange | positioned at a transmissive display area. In the multi-gap structure dot area, the reflective display area is thinner than the transmissive display area, so the alignment control force due to the oblique electric field generated at the edge of the island is increased, and the transmission area is increased. It becomes possible to control the alignment of the liquid crystal molecules in a wider area than the display area. Therefore, in this configuration, the island-shaped portion of the reflective display region is formed larger than the island-shaped portion of the transmissive display region, thereby improving the aperture ratio of the reflective display region and thereby obtaining a bright reflective display. I am doing so. Further, in the transflective liquid crystal display device, the luminance balance between the transmissive display and the reflective display may be changed in accordance with the characteristics of the mounted electronic device or the like. The brightness balance can be adjusted by enlarging the island portion.
Therefore, according to the liquid crystal display of this configuration, high-contrast display is possible without causing spot-like unevenness or burn-in in both the reflective display and the transmissive display, and a bright display can be obtained particularly in the reflective display. In addition, a liquid crystal display device that can be easily applied to a wide range of uses can be provided.
Next, the present invention includes a pair of substrates having electrodes on one surface side, and a liquid crystal layer sandwiched between the pair of substrates via the electrodes, and performing transmissive display in one dot region A liquid crystal display device provided with a region and a reflective display region for performing reflective display, wherein the liquid crystal layer includes liquid crystal having an initial alignment state of vertical alignment, and the transmissive display region and the reflective display region are different layers. The at least one electrode of the pair of substrates includes a plurality of island-shaped portions in the dot region and a connecting portion that electrically connects the adjacent island-shaped portions to each other. 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 alignment state of the liquid crystal when an electric field is applied to the electrodes in the planar region of each island-shaped portion Orientation control means for controlling Morphism the orientation control means arranged in the display area provides a liquid crystal display device characterized by having a smaller plane area the orientation control means disposed in the transmissive display region.
In this configuration, the orientation control means for the reflective display area is formed smaller than the orientation control means for the transmissive display area. As a result, the aperture ratio of the reflective display region is improved, and a bright reflective display can be obtained. In the dot region of the multi-gap structure, the reflective display region is formed with a thinner liquid crystal layer thickness than the transmissive display region. The alignment regulating force by the alignment control means provided on the electrode is also increased. Therefore, even if the orientation control means is reduced as in this configuration, the orientation control action equivalent to that of the transmissive display region can be obtained, and high-quality reflective display can be obtained in which spot-like unevenness and image sticking are effectively prevented. be able to.
Next, the present invention relates to an element substrate having a pixel electrode, a signal wiring extending along a side edge of the pixel electrode, a counter substrate having a counter electrode on one side, and the element substrate and the counter substrate. A liquid crystal layer sandwiched therebetween, and a liquid crystal display device provided with a transmissive display region for performing transmissive display and a reflective display region for performing reflective display in one dot region, The alignment state includes a liquid crystal exhibiting vertical alignment, and the transmissive display region and the reflective display region are formed to have different layer thicknesses, and the distance between the pixel electrode and the signal wiring in the reflective display region is the transmissive display region. The liquid crystal display device is characterized by being shorter than the above-mentioned distance.
This configuration defines the arrangement of pixel electrodes and signal lines in a multi-gap structure transflective vertical alignment mode liquid crystal display device. The liquid crystal display device has a signal wiring electrically connected to each pixel electrode in order to supply a voltage to the pixel electrode in each dot region. These signal wirings may cause an oblique electric field in the periphery depending on the voltage supplied to the pixel electrode. When such an oblique electric field acts on the liquid crystal in the display region, alignment disturbance occurs and the display quality is deteriorated. There is a fear. Therefore, it is preferable to dispose the pixel electrode and the signal wiring to some extent. However, if the distance between the pixel electrode and the signal wiring is increased, the aperture ratio of the dot region is lowered and the display becomes dark. Therefore, in this configuration, in a vertical alignment mode liquid crystal display device having a multi-gap structure, in the reflective display region where the liquid crystal layer is thin, the alignment regulating force by the electrode edge and alignment control means is larger than that in the transmissive display region. Therefore, the distance between the pixel electrode and the signal wiring is made larger in the transmissive display area than in the reflective display area. With such a configuration, it is possible to obtain a high-quality display in which spot-like unevenness and burn-in are prevented in both transmissive display and reflective display while minimizing the decrease in the aperture ratio of the dot region. It becomes like this.
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.
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 having a rectangular shape in plan view connected to the scanning line 13 via the TFD element 40 are arranged in a matrix. The common electrodes 9 are arranged in a strip shape (stripe shape) in plan view so as to face the electrode 31 in the direction perpendicular to the paper surface. 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 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.
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.
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.
An insulating film 26 is selectively formed on the color filter 22 </ b> R so as to be positioned above the reflective film 20. 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. 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 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.
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 edge of the flat surface on the upper side of the insulating film 26 and the edge of the island-shaped portion 31 a constituting the pixel electrode 31 on the upper substrate 25 side substantially coincide with each other and are formed by the insulating film 26. The boundary step region N is disposed at a position overlapping the connecting portion 31d between the island-shaped portions 31a and 31b in plan view.
A common electrode 9 made of a transparent conductive material such as ITO is formed on the surface of the lower substrate 10 including the surface of the insulating film 26. 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.
In this embodiment, the reflective film 20 and the common electrode 9 are separately provided and laminated. In the reflective display region R, a reflective film made of a metal material is used as a part of the common electrode. You can also
Next, 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 the planar shape shown in FIG. The pixel electrode 31 is formed, and the 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 by combining a polarizing plate, a λ / 2 retardation plate, a λ / 4 retardation plate, and a negative C plate can be employed. 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 due to the alignment control action similar to that of 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 to be narrower than 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. Therefore, it is possible to effectively suppress the deterioration of the connected 2 quality. 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.
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.
In the above-described 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, when the dot pitch is increased, the pixel electrode 31 is configured. Sometimes it is better to increase the number of islands. Even in that case, in the liquid crystal display device according to the present invention, the reflective display region and the transmissive display region are configured by the 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. To be placed between the islands. For example, in the case where 6 × 2 (12) island-shaped portions are arranged in the dot area, six island-shaped portions are allocated to the reflective display area, and the remaining six island-shaped portions are transmitted. Allocate to display area. And it arrange | positions so that the area | region between the island-shaped part arrange | positioned at the said reflective display area | region and the island-like part arrange | positioned at a transmissive display area | region may overlap with the said boundary level | step difference area | region N. FIG.
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. Therefore, for example, the reflective display region R having a thin liquid crystal layer is provided with an opening, 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.
Next, a liquid crystal display device according to a second embodiment will be described with reference to the drawings. FIG. 4 is a diagram showing a planar structure of the pixel region in the liquid crystal display device of the present embodiment, and corresponds to FIG. 3A of the first embodiment. The liquid crystal display device 200 of the present embodiment is a multi-gap transflective vertical alignment mode having the same configuration as the liquid crystal display device 100 shown in FIG. 3 except that the pixel electrode 32 having a different planar shape is provided. It is a liquid crystal display device. Therefore, in FIG. 4, the same reference numerals as those shown in FIG.
As shown in FIG. 4, in the liquid crystal display device 200 of the present embodiment, pixel electrodes 32 having a different planar shape from the previous liquid crystal display device 100 shown in FIG. 3 are provided in each of the dot regions D1 to D3. .
The pixel electrode 32 is formed of a transparent conductive material such as ITO, and is arranged in the dot region in the extending direction of the scanning line 13. The island-shaped portions 32 a to 32 c having a regular octagonal shape in plan view, and these island-shaped portions 32 a. ˜32c are provided with connecting portions 32d and 32e extending in the scanning line 13 direction so as to be conductively connected. Each of the connecting portions 32d and 32e connects the corner portions of the regular octagonal island portions 32a to 32c. Further, the boundary step region N is arranged so as to overlap with the connecting portion 32d connecting the island-like portion 32a arranged in the reflective display region R and the island-like portion 32b arranged in the transmissive display region T in a plane. Has been.
In the liquid crystal display device 200 of the present embodiment having the above-described configuration, the connecting portions 32d and 32e are extended from the corner portions of the island-shaped portions 32a to 32c to electrically connect the island-shaped portions, and the connecting portion 32d and the boundary step are provided. Since the area N and the area N are arranged so as to overlap with each other, a reduction in display quality due to the misalignment of the substrates 10 and 25 at the time of panel assembly can be suppressed, and a device for improving the ease of manufacturing has been made. It has become. In other words, the connecting portion 32d is arranged on the boundary step region N in terms of design, and when the panel is assembled according to the design, the display quality similar to that in the first embodiment is used. However, in the panel assembling process, for example, when the assembly position of the substrate 10 and the substrate 25 is shifted in the horizontal direction in the figure and a part of the island-shaped portion 32a or 32b overlaps the boundary step region N, the liquid crystal display device In 200, since the corner portion of the regular octagon overlaps with the boundary step region N, compared with the liquid crystal display device 100 of the first embodiment, the overlapping portion between the boundary step region N and the island-shaped portion can be narrowed. Disturbance of orientation in the islands 32a and 32b due to the region N can be reduced.
Further, in the liquid crystal display device 200 according to the present embodiment, even when disordered alignment or disclination occurs in the connection region between the island-shaped parts 32a to 32c and the connecting parts 32d and 32e, the display quality due to the disordered alignment is displayed. The influence on can be reduced. That is, since the side ends of the island portions 32a and 32b on the side of the connecting portion 32d are tapered toward the connecting portion 32d, the liquid crystal molecules are aligned at the corner portions due to the alignment regulating force of the oblique electric field at the time of voltage application. And tilted from both sides toward the line connecting the openings 9a and 9b. Therefore, even if the disclination occurs in the vicinity of the connection region between the connecting portion 32d and the island-like portions 32a and 32b, the disclination is caused by the above-mentioned orientation action from the island-like portions 32a and 32b to the connecting portion 32d or the opening. It moves smoothly toward the portions 9a and 9b, and the island-shaped portions 32a and 32b can maintain good orientation.
In the present embodiment, the connecting portions 32d and 32e are extended from the corner portions of the island-shaped portions 32a to 32c having a polygonal shape in plan view, but an island-like portion having an arbitrary shape other than the polygonal shape in plan view is formed. Even in this case, in the region where the island-shaped portion and the connecting portion are connected, if the electrode is formed in a substantially tapered shape from the island-shaped portion side toward the connecting portion, the misalignment is prevented in the panel assembling process. Even if it occurs, it is possible to suppress the overlap between the planar region of the island-shaped portion and the boundary step region N as much as possible, and it is possible to effectively suppress deterioration in display quality caused by the boundary step region N. Also, even if disclination occurs, the disclination can be moved to the connecting portion or the opening portion by the planar shape of the island-like portion, and the influence on the display can be reduced.
Next, a liquid crystal display device according to a third embodiment will be described with reference to the drawings. FIG. 5 is a diagram showing a planar structure of the pixel region in the liquid crystal display device of the present embodiment, and corresponds to FIG. 3A of the first embodiment. The liquid crystal display device 300 of this embodiment is a multi-gap transflective reflection device having the same configuration as the liquid crystal display device 100 shown in FIG. 3 except that the formation region of the reflective film for performing reflective display is mainly different. Type vertical alignment mode liquid crystal display device. Therefore, in FIG. 5, the same reference numerals as those shown in FIG.
As shown in FIG. 5, in the liquid crystal display device 300 of the present embodiment, a reflective film 220 having a different planar shape from the previous liquid crystal display device 100 shown in FIG. 3 is provided in each of the dot regions D1 to D3. .
The reflective film 220 is made of a metal film such as aluminum or silver, and among the island-shaped portions 31a to 31c constituting the pixel electrode 31 and the connecting portions 31d and 31e, the island-shaped portions 31b and 31c forming the transmissive display region T are formed. It is provided in the excluded dot area. In order to make the drawing easy to see, the reflection film 220 at a position overlapping with the island-shaped portion 31a is not shown. By extending the reflective film to the dot area outside the transmissive display area T in this way, the reflective film 220 can function as a light-shielding film, so that the contrast of transmissive display can be improved. It is done.
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 220 functioning as such 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 220 functioning as a light-shielding film in the non-display area as in this embodiment, it is possible to block these light leaks and obtain a high-contrast transmissive display.
In addition, since the insulating film 24 for giving uneven | corrugated shape to a reflecting film is not formed in area | regions other than the planar area | region (namely, reflective display area | region R) of the island-shaped part 31a, it is except for island-shaped parts 31a-31c. Even if external light is reflected by the reflective film 220 formed in the region (non-display region), the light is not reflected to the viewer side, and thus the quality of the reflective display is hardly affected. In the present embodiment, the color filters 22B, 22G, and 22R are provided in the respective dot regions D1 to D3. Further, in the region where the reflective film 220 is formed, the region excluding the planar region of the island portion 31a (that is, the dot region) (Non-display area), a color filter other than the display color of the dot area can be overlaid. With such a configuration, the light incident on the non-display areas of the dot areas D1 to D3 is absorbed by the superimposed color filter and also after being reflected by the reflective film 220. Light that has entered the non-display area hardly returns to the incident side, and a reflective display with higher contrast can be obtained. In addition, since the color filter overlapping arrangement can be realized relatively easily when the color filters 22R, 22G, and 22B are formed for each dot region, there is almost no inconvenience in the manufacturing process such as an increase in man-hours. .
In the present embodiment, the reflective film 220 is also provided in the planar regions of the coupling portions 31d and 31e. However, the reflective film 220 may be omitted from the coupling portions 31d and 31e. However, if the connecting portion 31d is shielded by the reflective film 220, a display defect portion due to orientation disorder in the connecting portion 31d overlapping the boundary step region N can be shielded, and a high contrast display can be obtained. In addition, the reflective film 220 can be easily patterned.
Next, a liquid crystal display device according to a fourth embodiment will be described with reference to the drawings. FIG. 6 is a diagram showing a planar structure of the pixel region in the liquid crystal display device of the present embodiment, and corresponds to FIG. 3A of the first embodiment. The liquid crystal display device 400 of the present embodiment is a multi-gap transflective vertical alignment mode having the same configuration as the liquid crystal display device 100 shown in FIG. 3 except that the pixel electrode 33 having a different planar shape is provided. It is a liquid crystal display device. Therefore, in FIG. 6, the same reference numerals as those shown in FIG.
As shown in FIG. 6, in the liquid crystal display device 300 of this embodiment, pixel electrodes 33 having a different planar shape from the previous liquid crystal display device 100 shown in FIG. 3 are provided in the respective dot regions D1 to D3. .
The pixel electrode 33 is formed of a transparent conductive material such as ITO, and is arranged in the dot line region in the extending direction of the scanning line 13 and has octagonal island-like portions 33a to 33c in plan view, and these island-like portions 33a to 33c. There are provided connecting portions 33d and 33e extending in the direction of the scanning line 13 so as to conductively connect the portions 33c. Each connection part 33d and 33e are extended from the edge which mutually adjoins octagonal island-shaped part 33a-33c, and has connected island-shaped part 33a-33c. Further, the boundary step region N is arranged so as to planarly overlap a connecting portion 33d connecting the island-shaped portion 33a disposed in the reflective display region R and the island-shaped portion 33b disposed in the transmissive display region T. Has been.
As shown in FIG. 6, the island-shaped portion 33 a forming the reflective display region R is formed to have a larger planar region than the island-shaped portions 33 b and 33 c arranged to form the transmissive display region T. . The openings 9a to 9c provided on the common electrode 9 side corresponding to the island-shaped portions 33a to 33c are formed to have the same planar shape and size.
In a transflective liquid crystal display device, the required display characteristics may differ depending on the use of the electronic device to be mounted. In such a case, the display area of the reflective display region R and the transmissive display region T is formed by forming the island-shaped portion 33a of the reflective display region R relatively large like the liquid crystal display device 400 of the present embodiment. The display characteristics of reflective display and transmissive display 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 edge portion of the island-shaped portion 33a is reduced by the island-shaped portion 33b of the transmissive display region T, It becomes larger than 33c. Therefore, even when the planar area of the island-shaped portion 33a is relatively large, the alignment state of the liquid crystal can be controlled well by the alignment regulating action by the island-shaped edge, 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.
Therefore, according to the liquid crystal display device 400 of the present embodiment, it is possible to adjust the reflective display and the transmissive display according to the application without degrading the display quality, and it is widely applied as a display unit of various electronic devices. be able to.
Next, a liquid crystal display device according to a fifth embodiment will be described with reference to the drawings. FIG. 7 is a diagram showing a planar structure of the pixel region in the liquid crystal display device of the present embodiment, and corresponds to FIG. 3A of the first embodiment. The liquid crystal display device 500 of the present embodiment has a multi-gap transflective reflection having the same configuration as that of the liquid crystal display device 100 shown in FIG. 3 except that the configuration of the color filter provided for each dot region is mainly different. Type vertical alignment mode liquid crystal display device. Therefore, in FIG. 7, the same components as those shown in FIG.
As shown in FIG. 7, in the liquid crystal display device 500 of the present embodiment, color filters 222B, 222G, and 222R having a different planar shape from the previous liquid crystal display device 100 shown in FIG. It is provided for each. In order to make the drawing easy to see, the reflection film 20 in the reflective display region R (planar region of the island-shaped portion 31a) and the uneven shape imparted to the reflective film 20 in the region are not shown.
The color filters 222R, 222G, and 222B have opening regions 22r, 22g, and 22b that are circular in plan view and are disposed in the planar region of the island-shaped portion 31a of the pixel electrode 31, respectively. Further, these opening regions 22r, 22g, and 22b are disposed concentrically with the opening portions 9a provided in the common electrode 9.
According to the liquid crystal display device 500 having the above-described configuration, areas (opening areas 22r, 22g, and 22b) that are not provided with color filters are provided in part of the reflective display area R. As a result, the brightness of the reflective display can be improved, and a high-quality display in which the brightness and chromaticity are balanced in both the reflective display and the transmissive display is possible.
Further, as shown in FIG. 7, the peripheral end portions of the opening regions 22r, 22g, and 22b are disposed apart from the side end portions of the island-shaped portion 31a and are also separated from the boundary step region N. In the side edge portion of the island portion 31a and the boundary step region N, alignment disturbance is likely to occur due to an oblique electric field or the like at the time of voltage application. Therefore, the color filters 222R, 222G, and 222B are disposed in these regions. Thus, it is difficult to visually recognize a decrease in display contrast or burn-in caused by the alignment disorder, and an improvement in the brightness of the reflective display region R can be realized without a substantial decrease in display quality.
Further, as shown in FIG. 7, the opening regions 22r, 22g, and 22b are formed to have different planar regions for the color filters 222R, 222G, and 222B. Specifically, it is formed in different sizes according to the visibility of each display color, the opening area 22g of the green color filter 222G is formed the largest, and the opening area 22r of the blue color filter 222R is the smallest. Is formed. Thus, by changing the sizes of the opening regions 22r, 22g, and 22b for each color, the color balance of the reflective display can be easily adjusted independently of the transmissive display, and the display quality can be further improved. be able to.
In this embodiment, the color filter opening regions 22r, 22g, and 22b are circular in plan view. However, the planar shape of the opening regions 22r, 22g, and 22b is not limited to this, and for example, the opening 9a and A ring-shaped opening region in which the color filter is left in the overlapping region can also be formed, and a regular octagon shape matching the outer shape of the island-shaped portion 31a can also be formed.
Next, a liquid crystal display device according to a sixth embodiment will be described with reference to the drawings. FIG. 8 is a diagram showing a planar structure of the pixel region in the liquid crystal display device of the present embodiment, and corresponds to FIG. 3A of the first embodiment. The liquid crystal display device 600 of this embodiment is a multi-gap having the same configuration as the liquid crystal display device 100 shown in FIG. 3 except that the configuration of the opening provided on the common electrode 9 and constituting the orientation control means is mainly different. This is a transflective vertical alignment mode liquid crystal display device of the type. Therefore, in FIG. 8, the same reference numerals as those shown in FIG.
As shown in FIG. 8, in the liquid crystal display device 600 of the present embodiment, an opening 19 a having a size different from that of the previous liquid crystal display device 100 shown in FIG. 3 is formed in the common electrode 9. These openings 19a, 9b, and 9c are provided by cutting the common electrode 9 into a circular shape at a position corresponding to the approximate center of the island-shaped portions 31a to 31c. May be provided.
Note that the size and shape of the island portions 31 a to 31 c constituting the pixel electrode 31 are substantially the same in the reflective display region R and the transmissive display region T.
As described in the fourth embodiment, the liquid crystal display device of the present invention employs a multi-gap structure, and the layer thickness of the liquid crystal layer 50 in the reflective display region R is equal to the layer thickness in the transmissive display region T. Since the thickness is thinner, in the reflective display region R, the alignment regulating force of the liquid crystal due to the oblique electric field is larger than that in the transmissive display region T. Accordingly, even in the opening provided on the common electrode 9 side, if the size is the same, the orientation regulating force is larger than that of the openings 9b and 9c provided in the transmissive display region T. Therefore, in the present embodiment, the reflective display region R is provided with the openings 19a smaller than the openings 9b and 9c of the transmissive display region T, so that the reflective display can be obtained while obtaining the same orientation regulating force as the transmissive display region T. The aperture ratio of the region R is improved so that a bright reflective display can be obtained.
The same applies to the case where the previous dielectric protrusion is used as the orientation control means instead of the openings 19a, 9b, 9c. In this case, the size of the dielectric protrusion disposed in the reflective display region R is the same. In addition, the height is formed smaller than the size and / or height of the dielectric protrusion in the transmissive display region T.
Next, a liquid crystal display device according to a seventh embodiment will be described with reference to the drawings. FIG. 9 is a diagram illustrating a planar structure of a pixel region in the liquid crystal display device of the present embodiment, and corresponds to FIG. 3A of the first embodiment. The liquid crystal display device 700 of the present embodiment is a multi-gap transflective vertical alignment mode having the same configuration as the liquid crystal display device 100 shown in FIG. 3 except that the pixel electrode 34 having a different planar shape is provided. It is a liquid crystal display device. Therefore, in FIG. 9, the same reference numerals as those shown in FIG.
As shown in FIG. 9, in the liquid crystal display device 700 of the present embodiment, pixel electrodes 34 having a different planar shape from the previous liquid crystal display device 100 shown in FIG. 3 are provided in the dot regions D1 to D3. .
The pixel electrode 34 is formed of a transparent conductive material such as ITO, and is arranged in the dot line region in the extending direction of the scanning line 13 and has octagonal island-shaped portions 34a to 34c in plan view, and these island-shaped portions 34a to 34c. There are provided connecting portions 34d and 34e extending in the direction of the scanning line 13 so as to conductively connect between 34c. Each connection part 34d and 34e is extended from the edge which adjoins the octagonal island-shaped part 34a-34c, and has connected the island-shaped part 34a-34c. Further, the boundary step region N is disposed so as to overlap with the connecting portion 34d connecting the island-shaped portion 34a disposed in the reflective display region R and the island-shaped portion 34b disposed in the transmissive display region T in a plane. Has been.
In the liquid crystal display device 700 of this embodiment, the planar distance between the scanning line 13 extending along the long side ends of the dot regions D1 to D3 and the island portions 34a to 34c is different from that of the reflective display region R. It is characterized in that it differs from the transmissive display region T. That is, the distance dr between the island-shaped portion 34 a in the reflective display region R and the scanning line 13 is shorter than the distance dt between the island-shaped portions 34 b and 34 c in the transmissive display region T and the scanning line 13.
Depending on the potential of the scanning line 13 (signal wiring) extending along the side edges of the dot regions D1 to D3, an oblique electric field may be generated in the vicinity, causing disturbance in the tilt direction of the vertically aligned liquid crystal. is there. Therefore, it is desirable that the island-shaped portions 34 a to 34 c of the pixel electrode 34 be arranged at some distance from the scanning line 13. However, when the distance between the scanning line 13 and the pixel electrode 34 is increased, the aperture ratios of the dot regions D1 to D3 are lowered, and there is a disadvantage that the display becomes dark.
Therefore, in this embodiment, as described in the previous fourth embodiment, since the liquid crystal layer is thick, the alignment regulating force at the edge portion of the island portion is relatively weak, and an oblique electric field generated in the scanning line 13 is generated. In the transmissive display region T that is easily affected by the above, the distance between the island-shaped portions 34b and 34c and the scanning line 13 is increased, and conversely, the liquid crystal layer is thin and the oblique electric field generated at the side edge of the island-shaped portion 34a. In the reflective display region R where the alignment regulation force is increased, the distance between the island-shaped portion 34a and the scanning line 13 is reduced.
With such a configuration, it is possible to optimize the distance between the scanning line 13 and the island-shaped portion in both the reflective display region R and the transmissive display region T, and display of an oblique electric field generated in the scanning line 13. It is possible to secure the maximum aperture ratio of the dot area while suppressing the influence on the dot area. Therefore, according to the liquid crystal display device 700 of the present embodiment, it is possible to obtain a bright and high-quality display that does not cause spot-like unevenness or image sticking.
In this embodiment, the case where the pixel switching element is a TFD element has been described. However, when the above configuration is applied to a liquid crystal display device including a TFT (thin film transistor) element as the pixel switching element, the pixel switching elements extend so as to cross each other. The island-shaped portions 34b and 34c of the transmissive display region T may be arranged apart from the island-shaped portions 34a of the reflective display region R with respect to both the scanning lines and the data lines.
In the present embodiment, the pixel electrode 34 has been described as having a planar shape in which a plurality of island-shaped portions 34a to 34c are connected by the connecting portions 34d and 34e. However, the pixel is a feature of the present embodiment. The positional relationship between the electrode and the signal wiring is effective regardless of the shape of the pixel electrode. That is, even in a liquid crystal display device having a pixel electrode having a substantially rectangular shape in plan view, the planar distance between the pixel electrode in the transmissive display region T and the signal wiring (scanning line 13) is the pixel electrode in the reflective display region R and the signal wiring. The effect of the above embodiment can be obtained by changing the planar shape of the pixel electrode or the routing of the signal wiring so that the distance is larger than the distance between and the orientation of the reflective display region and the transmissive display region. It is possible to obtain a high-quality display without causing spot-like unevenness or brightness reduction due to disturbance.
Next, a liquid crystal display device according to an eighth embodiment will be described with reference to the drawings. FIG. 10 is a diagram illustrating a planar structure of a pixel region in the liquid crystal display device of the present embodiment, and corresponds to FIG. 3A of the first embodiment. The liquid crystal display device 800 of the present embodiment is characterized by a multi-gap characterized in that the extending direction of the common electrode 9 and the scanning line 13 with respect to the pixel electrode 31 is different from that of the previous liquid crystal display device 100 shown in FIG. This is a transflective vertical alignment mode liquid crystal display device of the type. In FIG. 10, the same reference numerals as those shown in FIG.
As shown in FIG. 10, in each of the dot regions D1 to D3 of the liquid crystal display device 800 of the present embodiment, a plurality of island portions 31a to 31c arranged in the long side direction of the dot region and a connection that connects them. A pixel electrode 31 including portions 31d and 31e is provided, and each pixel electrode 31 is connected with a TFD element 40 connected to a scanning line 130 extending in the dot region short side direction (vertical direction in the drawing). . The common electrodes 9 extending in the long side direction of the dot regions D1 to D3 are arranged in a stripe shape in plan view. Openings 9 a to 9 c are provided in the common electrode 9, and the openings 9 a to 9 c are arranged at positions corresponding to the surface centers of the island-shaped portions 31 a to 31 c of the pixel electrode 31, respectively.
In the liquid crystal display device 800 having the above configuration, since the scanning lines 13 are arranged along the short sides of the dot areas D1 to D3, the oblique electric field areas generated in the vicinity of the scanning lines 13 are the dot areas D1 to D3. Can be made narrower. Thereby, even if the distance between the scanning line 13 and the island-shaped portions 31a and 31c adjacent to the scanning line 13 is sufficiently large, the aperture ratio of the dot regions D1 to D3 is not reduced so much, and the reflective display is performed. A high aperture ratio can be obtained in both the region R and the transmissive display region T. Therefore, according to the liquid crystal display device 800 of this embodiment, it is possible to prevent spot-like unevenness and image sticking due to the alignment disorder due to the scanning lines 13, and to obtain a bright display.
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 above-described embodiment, the configuration in which the island-shaped portions 31 a to 31 c are electrically connected to the pixel electrode 31 on the upper substrate 25 side is applied. However, such a configuration can also be applied to the common electrode 9. In this case, a plurality of island portions electrically connected to each other are provided on the common electrode in the dot region, and the island portions are electrically connected across the dot region.
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 openings 9a to 9c are formed in the planar regions of the islands 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.
FIG. 11 is a perspective view showing an example of an electronic apparatus according to the 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, videophones, 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 illustrating a pixel region of the liquid crystal display device of the second embodiment. FIG. 5 is a plan configuration diagram illustrating a pixel region of the liquid crystal display device of the third embodiment. FIG. 6 is a plan configuration diagram illustrating a pixel region of the liquid crystal display device of the fourth embodiment. FIG. 7 is a plan configuration diagram illustrating a pixel region of the liquid crystal display device of the fifth embodiment. FIG. 8 is a plan configuration diagram illustrating a pixel region of the liquid crystal display device of the sixth embodiment. FIG. 9 is a plan configuration diagram illustrating a pixel region of a liquid crystal display device according to a seventh embodiment. FIG. 10 is a plan configuration diagram illustrating a pixel region of a liquid crystal display device according to an eighth embodiment. FIG. 11 is a perspective configuration diagram illustrating an example of an electronic apparatus according to the invention.
DESCRIPTION OF SYMBOLS 9 ... Common electrode (data line), 13 ... Scan line (signal wiring), 20, 220 ... Reflective film, 24 ... Insulating film (light scattering imparting means), 26 ... Insulating film (liquid crystal layer thickness adjusting layer), 31- 34 ... Pixel electrode, 50 ... Liquid crystal layer, R ... Reflection display area, T ... Transmission display area
A pair of substrates having electrodes on one side and a liquid crystal layer sandwiched between the pair of substrates via the electrodes are provided, and a transmissive display region for performing transmissive display and a reflective display are performed within one dot region A liquid crystal display device, wherein the liquid crystal layer includes a liquid crystal having negative dielectric anisotropy, and the liquid crystal layer thickness of the reflective display region is smaller than the liquid crystal layer thickness of the transmissive display region. There ,
Within the dot area,
An adjustment layer for adjusting the liquid crystal layer thickness is provided on one of the pair of substrates,
The electrode provided on the substrate facing the one substrate is
A plurality of island-shaped portions, and a connecting portion that electrically connects the adjacent island-shaped portions to each other;
The plurality of island-shaped portions are arranged in an integer number in each of the transmissive display area and the reflective display area,
The boundary step region having a different liquid crystal layer thickness is provided between the island-shaped portion disposed in the transmissive display region and the island-shaped portion disposed in the reflective display region, and the connecting portion is provided in the boundary step region. A liquid crystal display device, wherein the liquid crystal display device is disposed in a corresponding region .
The liquid crystal display device according to claim 1, wherein the island-shaped portion is formed in the same shape in a plan view in each of the reflective display area and the transmissive display area.
The liquid crystal display device according to claim 1, wherein an alignment control means for controlling an alignment state of the liquid crystal when an electric field is applied is provided in a planar region of the island-shaped portion.
The liquid crystal display device according to claim 3, wherein the orientation control means is provided at a substantially central portion of a planar region of the island-shaped portion.
5. The liquid crystal display device according to claim 3, wherein the orientation control means is an opening provided in an electrode facing the island-like portion with a liquid crystal layer interposed therebetween.
5. The liquid crystal display device according to claim 3, wherein the alignment control means is a protrusion made of an insulating material provided on an electrode facing the island-like portion with a liquid crystal layer interposed therebetween.
The liquid crystal display device according to claim 1, wherein the island-shaped portion has a circular shape or a regular polygonal shape in plan view.
The planar shape of the electrode in the connection region between the island-shaped portion and the connecting portion is a tapered shape from the island-shaped portion side toward the connecting portion side. A liquid crystal display device according to 1.
9. The liquid crystal display device according to claim 1, wherein the connecting portion is extended from a side end or a corner portion that protrudes outward from the island-shaped portion in a plan view.
In the dot area, comprising a reflective film partially provided including the reflective display area,
The liquid crystal display device according to claim 1, wherein the reflective film is formed so as to cover the inside of the dot region excluding the transmissive display region.
11. The liquid crystal display device according to claim 10, wherein the reflective film is formed so as to cover a dot region excluding a planar region of an island-like portion disposed in the transmissive display region.
An electronic apparatus comprising the liquid crystal display device according to claim 1 .
JP2003282775A 2003-07-30 2003-07-30 Liquid crystal display device and electronic device Active JP3900123B2 (en)
JP2003282775A JP3900123B2 (en) 2003-07-30 2003-07-30 Liquid crystal display device and electronic device
US10/889,250 US7242448B2 (en) 2003-07-30 2004-07-13 Liquid crystal device and electronic apparatus
TW93121362A TWI299098B (en) 2003-07-30 2004-07-16
CN 200710107474 CN100478767C (en) 2003-07-30 2004-07-29 Liquid crystal display device and electronic device
CN 200410070352 CN1324352C (en) 2003-07-30 2004-07-29 Liquid crystal device and electronic apparatus
EP20040254589 EP1505428B1 (en) 2003-07-30 2004-07-30 Liquid crystal device and electronic apparatus
KR20040060067A KR100664821B1 (en) 2003-07-30 2004-07-30 Liquid crystal device and electronic apparatus
DE200460016924 DE602004016924D1 (en) 2003-07-30 2004-07-30 Liquid crystal device and electronic device
US11/502,356 US7307681B2 (en) 2003-07-30 2006-08-11 Liquid crystal device and electronic apparatus
KR20060098983A KR100767874B1 (en) 2003-07-30 2006-10-11 Liquid crystal device
US11/797,746 US7907239B2 (en) 2003-07-30 2007-05-07 Liquid crystal device and electronic apparatus
KR1020070070883A KR100790648B1 (en) 2003-07-30 2007-07-13 Liquid crystal device
US11/889,483 US7924376B2 (en) 2003-07-30 2007-08-14 Liquid crystal device and electronic apparatus
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JP2003282775A Active JP3900123B2 (en) 2003-07-30 2003-07-30 Liquid crystal display device and electronic device
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JP4128410B2 (en) 2002-08-01 2008-07-30 日本放送協会 Projection image alignment device for projection display device
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