JP2004205902A - Liquid crystal display device and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transflective liquid crystal display capable of obtaining a bright display high in contrast and wide in viewing angle. <P>SOLUTION: In this liquid crystal display device adopting a vertical alignment mode using a liquid crystal layer of vertical alignment in the initial alignment state, a reflection display region R encloses the surroundings of a transmission display region T in one dot and an insulation layer 21 for adjusting the thickness of liquid crystal layer is provided the region corresponding to the reflection display region R of the dot peripheral part. In a substrate (a counter substrate) on the side opposite to the side where the insulation film 21 is formed, an aperture part 31s is provided at a common electrode in a position corresponding to the boundary region between the reflection display region R and the transmission display region T and electrode parts on the inner and the outer sides of the aperture part are conducted with each other by a conduction part 31c of a corner part. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal display device and an electronic apparatus, and more particularly to a technique capable of obtaining a display with a high contrast and a wide viewing angle in a transflective liquid crystal display device that performs display in both a reflection mode and a transmission mode. .
[0002]
[Prior art]
There has been proposed a liquid crystal display device in which external light is used in a bright place similarly to a reflective liquid crystal display device, and in a dark place, the display can be visually recognized by an internal light source such as a backlight. In other words, this liquid crystal display device employs a display system that has both a reflective type and a transmissive type, and reduces power consumption by switching between the reflective mode and the transmissive mode according to the surrounding brightness. In addition, even when the surroundings are dark, clear display can be performed, which is suitable for a display unit of a portable device. Hereinafter, in this specification, this type of liquid crystal display device is referred to as a “semi-transmissive reflective liquid crystal display device”.
[0003]
As such a transflective liquid crystal display device, a liquid crystal layer is sandwiched between an upper substrate and a lower substrate, and a reflection film in which an opening for light transmission is formed in a metal film such as aluminum is disposed below. There has been proposed a liquid crystal display device provided on the inner surface of a substrate and using this reflection film 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 reflection film on the inner surface of the lower substrate, passes through the liquid crystal layer again, and is emitted from the upper substrate side, contributing to display. I do. On the other hand, in the transmission mode, light from the backlight incident from the lower substrate side passes through the liquid crystal layer from the opening of the reflection film, and then exits from the upper substrate side to contribute to display. Therefore, of the reflective film forming region, the region where the opening is formed is the transmissive display region, and the other region is the reflective display region.
[0004]
However, the conventional transflective liquid crystal 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 restriction that reflective 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, Patent Document 1 proposes a new transflective liquid crystal display device using a vertically aligned liquid crystal. The features are the following three points.
(1) A "VA (Vertical Alignment) mode" in which a liquid crystal having a negative dielectric anisotropy is vertically aligned with respect to a substrate and is tilted by applying a voltage.
(2) A multi-gap structure in which the liquid crystal layer thickness (cell gap) of the transmissive display area and the reflective display area is different.
(3) The transmissive display area is a regular octagon or a circle, and a projection is provided at the center of the transmissive display area on the opposing substrate so that the liquid crystal falls isotropically in this area. That is, an "alignment division structure" is adopted.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-350853
[Problems to be solved by the invention]
As described above, in the liquid crystal display device of Patent Document 1, the projection is provided at the center of the transmissive display region to control the orientation direction of the liquid crystal. By the way, in the field of application to portable devices and the like, brighter and higher-contrast displays are required, and the tendency to emphasize transmissive display over reflective display is increasing. Under such circumstances, the area occupied by the transmissive display area within one dot is increasing. Then, as in the configuration disclosed in Patent Literature 1, there is a possibility that alignment control may not be performed completely only by providing a projection in the center of the transmissive display region, and alignment disorder called disclination occurs. There is a problem that display failure such as an afterimage is caused.
[0007]
The present invention has been made in order to solve the above-described problems, and in a transflective liquid crystal display device, a display defect such as an afterimage is suppressed, and furthermore, a liquid crystal capable of achieving higher luminance and higher contrast is provided. It is an object to provide a display device.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a liquid crystal display device of the present invention has a liquid crystal layer sandwiched between a pair of substrates, and has a transmissive display area for performing transmissive display in one dot area and a reflective display for performing reflective display. A liquid crystal display device provided with a region, wherein the liquid crystal layer is made of a liquid crystal having a negative dielectric anisotropy in which an initial alignment state exhibits vertical alignment, and at least one of the pair of substrates and the liquid crystal layer. Between the liquid crystal layer, a liquid crystal layer thickness adjustment layer that varies the thickness of the liquid crystal layer in the reflective display area and the transmissive display area is provided at least in the reflective display area, and the liquid crystal layer thickness adjustment layer is An inclined surface is provided near a boundary between the reflective display region and the transmissive display region, and electrodes for driving the liquid crystal are provided on inner surfaces of the pair of substrates, respectively, among the electrodes of the pair of substrates. at least The other electrode is provided with a substantially rectangular slit-shaped opening at a position corresponding to the inclined surface, and a conducting portion that conducts between the electrode portion inside the opening portion and the outside electrode portion is provided in the opening portion. It is characterized by being provided near the corner. Here, "providing an opening at a position corresponding to the inclined surface of the liquid crystal layer thickness adjusting layer" means "an opening at a position at least partially overlapping the inclined surface of the liquid crystal layer thickness adjusting layer when viewed in a plan view." Is provided. "
[0009]
The liquid crystal display device of the present invention is obtained by combining a transflective liquid crystal display device with a liquid crystal in a vertical alignment mode. In recent years, in a transflective liquid crystal display device, in order to solve the problem of a decrease in contrast due to a retardation difference in both the reflective and transmissive display modes, for example, an insulating film having a predetermined thickness is formed in a reflective display region on a lower substrate by a liquid crystal. There has been proposed a structure in which the thickness of the liquid crystal layer is changed between the reflective display area and the transmissive display area by being formed so as to protrude toward the layer side. The present applicant has already applied for many inventions relating to this type of liquid crystal display device. According to this configuration, the thickness of the liquid crystal layer in the reflective display area is reduced by the presence of the insulating film (in the present specification, the insulating film performing such a function is referred to as a “liquid crystal layer thickness adjustment layer”). Can be made smaller than the thickness of the liquid crystal layer, so that the retardation contributing to the reflective display and the retardation contributing to the transmissive display can be made sufficiently close or substantially equal, thereby improving the contrast. .
[0010]
Therefore, the present inventors have found that by combining a liquid crystal display device having the above-described insulating film with a liquid crystal layer of a vertical alignment mode, the alignment direction of the liquid crystal in the vertical alignment mode when an electric field is applied can be controlled. In other words, when the vertical alignment mode is adopted, a liquid crystal having a negative dielectric anisotropy (negative liquid crystal) is generally used. Since the liquid crystal molecules are tilted by the application, the direction in which the liquid crystal molecules are tilted cannot be controlled without any contrivance (unless the pretilt is provided), and misalignment (disclination) occurs, resulting in display failure and display. It degrades the quality. Therefore, in adopting the vertical alignment mode, control of the alignment direction of liquid crystal molecules when an electric field is applied is an important factor. Therefore, in a liquid crystal display device having the above-mentioned liquid crystal layer thickness adjustment layer, the liquid crystal layer thickness adjustment layer protrudes toward the liquid crystal layer, and furthermore, the liquid crystal layer thickness adjustment layer has its film thickness continuously changing. Since the liquid crystal molecules have the inclined surface, the liquid crystal molecules stand perpendicular to the inclined surface and have a pretilt corresponding to the angle of the inclined surface.
[0011]
However, only the function of the inclined surface of the liquid crystal layer thickness adjusting layer has a weak alignment control force, and it cannot be said that the alignment control is always sufficiently performed. Then, the present inventors set the position corresponding to the inclined surface (the position overlapping the inclined surface in plan view) with respect to the electrode on the side provided with the liquid crystal layer thickness adjustment layer or the electrode on the substrate on the opposite side. The present inventors have conceived of a configuration in which an opening is provided. By providing the openings in the electrodes, the electric field (potential line) generated between the electrodes on both substrates is obliquely distorted in the vicinity of the openings, and the action of the distorted oblique electric field makes it easier to control the alignment of the liquid crystal. Can be realized. In the configuration of the present invention, since the inclined surface of the liquid crystal layer thickness adjustment layer exists at the boundary between the transmissive display area and the reflective display area, for example, if the transmissive display area is provided at the center of one dot area, The entire periphery of the region is surrounded by the inclined surface of the liquid crystal layer thickness adjustment layer. Since the openings of the electrodes are provided at positions corresponding to the inclined surfaces, the entire periphery of the transmissive display region is a region where the alignment control force of the liquid crystal is strongly applied. Therefore, as compared with the configuration described in Patent Document 1 in which only one projection is provided at the center of the transmissive display area, alignment control is performed more sufficiently, and display defects due to disclination can be suppressed. As a result, a high-brightness, high-contrast liquid crystal display device can be provided.
[0012]
In addition, since the shape of the opening is substantially rectangular, the orientation direction of the liquid crystal molecules is defined in four directions perpendicular to each side of the rectangle. As a result, one dot region has four different orientation directions. Since the orientation division structure can be realized, a wide viewing angle can be achieved.
[0013]
By the way, if the slit is simply formed in a closed annular shape, the electrode portion inside the slit-shaped opening becomes an island shape, and conduction with the electrode portion outside the opening cannot be obtained. Therefore, a conductive part between the outer electrode part and the inner electrode part is essential. However, since the conductive part has a weak control of the alignment of the liquid crystal, disclination is likely to occur around this part. On the other hand, in the present invention, since such a conductive portion is provided at the corner of the opening, disclination is smaller than when the conductive portion is provided at the center of the edge of the opening. Generation can be suppressed. That is, since the liquid crystal molecules at the corners are affected by the alignment of the liquid crystal molecules on both the long side and the short side of the opening, the alignment performance is higher than that of the liquid crystal molecules at the center of the edge of the opening. . Therefore, by forming the conducting portion at a position having a high alignment performance, the occurrence of disclination can be suppressed. In particular, in the above configuration, since the orientation division of the entire pixel is sufficiently performed by the effect of the opening, disclination is less likely to occur at the corner. Also, even if disclination occurs, its influence on the display is a very small area at the corner, and does not significantly affect the display, the response speed, and the like. Note that the vicinity of the corner portion refers to a predetermined range from the end of the electrode portion inside the opening, and this predetermined range is, for example, a distance of １ ／ of the length of the edge of the inside electrode portion. Is defined as a range.
[0014]
Note that such conductive portions are preferably provided at a plurality of corners of the opening, so that the occurrence of point defects due to disconnection of the conductive portions can be suppressed.
Further, in addition to the above-described configuration, by providing an opening at a position corresponding to substantially the center of the transmissive display area of the electrode opposite to the electrode provided with the slit-shaped opening, the alignment control force in the transmissive display area can be reduced. It is possible to further enhance the display quality such as contrast. Alternatively, a projection may be provided instead of the opening. When a projection (projection) is provided on the electrode, the orientation direction of the liquid crystal can be controlled by the action of the projection projecting into the liquid crystal layer. Although the mechanism is different as described above, it is possible to replace the “opening of the electrode” with the “projection on the electrode” as a means for controlling the alignment direction of the liquid crystal molecules.
In addition, by providing a substantially circularly polarized light incident means for causing substantially circularly polarized light to enter each of the pair of substrates, favorable display can be performed in both reflective display and transmissive display.
[0015]
An electronic apparatus according to the present invention includes the liquid crystal display device according to the present invention.
According to this configuration, it is possible to provide an electronic apparatus having a bright, high-contrast, wide-viewing-angle liquid crystal display unit regardless of the use environment.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The liquid crystal display device of this embodiment is an example of an active matrix liquid crystal display device using thin film transistors (hereinafter, abbreviated as TFTs) as switching elements.
[0017]
FIG. 1 is an equivalent circuit diagram of a plurality of dots arranged in a matrix forming an image display area of the liquid crystal display device of the present embodiment, FIG. 2 is a plan view showing a structure inside the dots of a TFT array substrate, and FIG. 3 is a cross-sectional view showing the structure of the liquid crystal device, which is a cross-sectional view taken along line AA ′ of FIG. In the following drawings, the scale of each layer and each member is different in order to make each layer and each member have a size recognizable in the drawings.
[0018]
In the liquid crystal display device of the present embodiment, as shown in FIG. 1, a plurality of dots arranged in a matrix forming an image display area include a pixel electrode 9 and a switching element for controlling the pixel electrode 9. Are formed, and the data line 6a to which an image signal is supplied is electrically connected to the source of the TFT 30. The image signals S1, S2,..., Sn to be written to the data lines 6a are supplied line-sequentially in this order or supplied to a plurality of adjacent data lines 6a for each group. The scanning lines 3a are electrically connected to the gates of the TFTs 30, and the scanning signals G1, G2,..., Gm are applied to the plurality of scanning lines 3a in a pulsed line-sequential manner at a predetermined timing. The pixel electrode 9 is electrically connected to the drain of the TFT 30. When the TFT 30 serving as a switching element is turned on for a predetermined period, the image signals S1, S2,... Write at the timing of
[0019]
The image signals S1, S2,..., Sn of a predetermined level written in the liquid crystal through the pixel electrodes 9 are held for a certain period between the common electrodes described later. The liquid crystal modulates light by changing the orientation and order of the molecular assembly depending on the applied voltage level, thereby enabling gray scale display. Here, in order to prevent the held image signal from leaking, a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9 and the common electrode. Note that reference numeral 3b is a capacitance line.
[0020]
Next, a planar structure of a TFT array substrate included in the liquid crystal device according to the present embodiment will be described with reference to FIG.
As shown in FIG. 2, on the TFT array substrate 10, a plurality of rectangular pixel electrodes 9 (outlined by dotted lines 9A) are provided in a matrix, and each pixel electrode 9 extends along the vertical and horizontal boundaries of the pixel electrode 9. A data line 6a, a scanning line 3a and a capacitance line 3b are provided. In the present embodiment, one dot region is inside a region where each pixel electrode 9 and the data line 6a, the scanning line 3a, the capacitor line 3b, and the like provided so as to surround each pixel electrode 9 are formed. The structure is such that display is possible for each dot region arranged in a matrix.
[0021]
The data line 6a is electrically connected to a source region, which will be described later, of the semiconductor layer 1a constituting the TFT 30, for example, a polysilicon film via the contact hole 5, and the pixel electrode 9 is connected to the semiconductor layer 1a. Among them, it is electrically connected to a drain region described later via a contact hole 8. In addition, the scanning line 3a is arranged to face the channel region (the diagonally shaded region ascending in the figure) of the semiconductor layer 1a, and the scanning line 3a functions as a gate electrode in a portion facing the channel region. .
The capacitance line 3b is formed from a main line portion extending substantially linearly along the scanning line 3a (that is, a first region formed along the scanning line 3a when viewed in plan) and a portion intersecting the data line 6a. And a projection (ie, a second region extending along the data line 6a when viewed in a plan view) protruding forward (upward in the figure) along the data line 6a. In FIG. 2, a plurality of first light-shielding films 11a are provided in a region indicated by oblique lines rising to the right.
[0022]
More specifically, the first light-shielding film 11a is provided at a position covering the TFT 30 including the channel region of the semiconductor layer 1a as viewed from the TFT array substrate side, and further, is opposed to the main line of the capacitor line 3b. A main line portion extending linearly along the scanning line 3a, and a protruding portion protruding from a location intersecting the data line 6a toward a subsequent stage (that is, downward in the drawing) adjacent to the data line 6a. The tip of the downward projection in each stage (pixel row) of the first light-shielding film 11a overlaps the tip of the upward projection of the capacitor line 3b in the next stage below the data line 6a. A contact hole 13 for electrically connecting the first light-shielding film 11a and the capacitance line 3b to each other is provided in the overlapping portion. That is, in the present embodiment, the first light-shielding film 11 a is electrically connected to the preceding or subsequent capacitive line 3 b by the contact hole 13.
[0023]
As shown in FIG. 2, a rectangular frame-shaped reflection film 20 is formed on the periphery of one dot region, and the region where the reflection film 20 is formed becomes a reflection display region R, and the reflection film inside the reflection display region R is formed. The area where 20 is not formed is the transmissive display area T. In addition, a rectangular frame-shaped insulating film 21 (liquid crystal layer thickness adjusting layer) is formed so as to include the formation region of the reflective film 20 when viewed in a plan view. In the case of the present embodiment, the insulating film 21 has the inclined surface 21a, and in this specification, this portion is defined as a boundary region between the reflective display region R and the transmissive display region T. The common electrode 31 on the opposite substrate 25 described later has a slit-shaped opening 31s for each dot region, and the opening 31s has a substantially rectangular frame shape in plan view. However, if the rectangle is completely closed, the common electrode 31 is divided between the inside and the outside of the rectangle, and it becomes difficult to apply a voltage to both sides. Therefore, in the case of the present embodiment, the connecting portion (conductive portion) 31c of the common electrode 31 is provided at the corner of the rectangle. It is sufficient that at least one connecting portion 31c is provided. However, by providing such connecting portions 31c at a plurality of locations (two locations in FIG. 2), the probability of disconnection can be reduced. In the case of the present embodiment, the width of the opening 31s is formed to be larger than the width of the boundary region (the inclined surface 21a of the insulating film). On the other hand, a slit-shaped opening 9s is formed in the pixel electrode 9 at a position corresponding to the center of the transmissive display region T.
[0024]
Next, a sectional structure of the liquid crystal display device of the present embodiment will be described with reference to FIG. FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG. 2. However, the present invention is characterized by the configuration of the insulating film and the electrodes, and the cross-sectional structure of the TFT and other wirings is not different from the conventional one. Illustration and description of the TFT and the wiring portion are omitted.
[0025]
As shown in FIG. 3, a liquid crystal layer 50 made of a liquid crystal having a negative dielectric anisotropy and exhibiting a vertical initial alignment state is sandwiched between a TFT array substrate 10 and an opposing substrate 25 disposed opposite thereto. I have. In the TFT array substrate 10, a reflective film 20 made of a metal film having a high reflectivity such as aluminum or silver is formed on the surface of a substrate main body 10A made of a translucent material such as quartz or glass. As described above, the area where the reflective film 20 is formed becomes the reflective display area R, and the area where the reflective film 20 is not formed becomes the transmissive display area T. On the reflective film 20 located in the reflective display region R and on the substrate body 10A located in the transmissive display region T, a dye layer 22 constituting a color filter is provided. In the pigment layer 22, pigment layers of different colors of red (R), green (G), and blue (B) are arranged for each adjacent dot region, and one pixel is constituted by three adjacent dot regions. I do. Alternatively, in order to compensate for the difference in the saturation of the display color between the reflective display and the transmissive display, a dye layer having a different color purity between the reflective display region R and the transmissive display region T may be separately provided.
[0026]
On the dye layer 22 of the color filter, an insulating film 21 is formed at a position corresponding to the reflective display region R (peripheral portion of the dot region). The insulating film 21 is made of, for example, an organic film such as an acrylic resin having a thickness of about 2 μm ± 1 μm, and has an inclined surface near the boundary between the reflective display region R and the transmissive display region T so that its own layer thickness changes continuously. 21a. Since the thickness of the liquid crystal layer 50 in the portion where the insulating film 21 does not exist is about 2 to 6 μm, the thickness of the liquid crystal layer 50 in the reflective display region R is about half the thickness of the liquid crystal layer 50 in the transmissive display region T. That is, the insulating film 21 functions as a liquid crystal layer thickness adjustment 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 thickness. In the case of the present embodiment, the edge of the flat surface above the insulating film 21 and the edge of the reflective film 20 (reflective display area) substantially match, and the inclined surface 21a is included in the transmissive display area T. .
[0027]
On the surface of the TFT array substrate 10 including the surface of the insulating film 21, a pixel electrode 9 made of a transparent conductive film such as indium tin oxide (hereinafter abbreviated as ITO) is formed. The pixel electrode 9 has a slit-shaped opening 9s at the center of the transmissive display area. An alignment film 23 made of polyimide or the like is formed on the pixel electrode 9.
[0028]
On the other hand, on the counter substrate 25 side, a common electrode 31 made of a transparent conductive film such as ITO and an alignment film 33 made of polyimide or the like are sequentially formed on a substrate body 25A made of a light-transmitting material such as glass or quartz. . As described above, the common electrode 31 is formed with the slit-shaped opening 31s having a substantially rectangular frame shape in plan view, and the opening 31s is located above the inclined surface 21a of the insulating film 21. Both the alignment films 23 and 33 of the TFT array substrate 10 and the counter substrate 25 are subjected to vertical alignment processing, but are not provided with a means for imparting pretilt such as rubbing.
[0029]
Further, on the outer surface side of the TFT array substrate 10 and on the outer surface side of the counter substrate 25, retardation plates 43 and 41 and polarizing plates 44 and 42 are provided from the substrate body side, respectively. The phase difference plates 43 and 41 have a phase difference of about 1/4 wavelength with respect to the wavelength of visible light, and the combination of the phase difference plates 43 and 41 and the polarizing plates 44 and 42 makes the TFT array substrate 10 side In addition, substantially circularly polarized light is incident on the liquid crystal layer 50 from both of the liquid crystal layer 50 and the counter substrate 25 side. A backlight 64 having a light source 61, a reflector 62, a light guide plate 63, and the like is provided outside the liquid crystal cell on the outer surface side of the TFT array substrate 10.
[0030]
According to the liquid crystal display device of the present embodiment, the thickness of the liquid crystal layer 50 in the reflective display region R is reduced to approximately half the thickness of the liquid crystal layer 50 in the transmissive display region T by providing the insulating film 21 in the reflective display region R. Since the size can be reduced, the retardation contributing to the reflective display and the retardation contributing to the transmissive display can be made substantially equal, thereby improving the contrast. Further, since slit-shaped openings 9s and 31s are provided at positions corresponding to the center of the pixel electrode 9 and the boundary region of the common electrode 31, respectively, the electric field applied between the upper and lower electrodes is obliquely distorted, and the oblique electric field is generated. Can control the alignment direction of the liquid crystal molecules 50b. Furthermore, the liquid crystal molecules 50b in the dot area fall in four directions when a voltage is applied by the action of the opening 31s of the common electrode 31, so that the viewing angle characteristics can be expanded.
[0031]
In the present embodiment, the electrode 31 of the transmissive display region T and the electrode 31 of the reflective display region R which are adjacent to each other via the opening 31s are connected by a connecting portion 31c provided at a corner of the opening 31s. Therefore, the occurrence of disclination in the vicinity of the connecting portion 31c can be suppressed. Normally, since such a connection portion 31c has a weak alignment control force, disclination is likely to occur at this portion. On the other hand, the liquid crystal molecules at the corner connection portion 31c are more easily controlled by the liquid crystal molecules at the adjacent edge of the opening than the liquid crystal molecules located at the center of the edge of the opening. For this reason, in the present configuration in which the connecting portion 31c is provided at the corner of the opening 31s, the occurrence of disclination in the vicinity of the connecting portion 31c is suppressed. A high-quality display with little roughness and unevenness when observed from an oblique direction can be obtained.
[0032]
In the liquid crystal display device of the present embodiment, by such an operation, a display with a high contrast and a wide viewing angle (a contrast of 1:10 or more with a 160 ° cone) can be realized without display defects such as light leakage. Can be.
[0033]
[Second embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
FIG. 4 is a sectional view showing the liquid crystal display device of the present embodiment. Since the basic configuration of the liquid crystal display device of the present embodiment is exactly the same as that of the first embodiment, the same reference numerals in FIG. 4 denote the same components as in FIG. 3, and a detailed description thereof will be omitted. .
[0034]
In the case of the present embodiment, as shown in FIG. 4, a ridge (convex portion) 9t having a triangular cross section is formed on the pixel electrode 9 on the TFT array substrate 10 side. The ridges 9t are formed of a dielectric material such as an acrylic resin, for example, and have a planar shape at the center of the dot region, similar to the shape of the opening 9s shown in FIG. 2 of the first embodiment. It is formed in a straight line. Then, an alignment film 23 is formed so as to cover the pixel electrode 9 and the ridge 9t. On the other hand, on the counter substrate 25 side, similar to the first embodiment, the common electrode 31 is formed with a slit-shaped opening 31s having a substantially rectangular frame shape in plan view. The opening 31s is located above the inclined surface 21a of the insulating film 21.
[0035]
According to the liquid crystal display device of the present embodiment, on the counter substrate 25 side, the oblique electric field generated by the opening 31s of the common electrode 31 acts, and on the TFT array substrate 10 side, the projections 9t protruding into the liquid crystal layer 50 are formed. The orientation of the liquid crystal molecules 50b can be controlled by the shape effect. Thus, display with high contrast and a wide viewing angle can be realized without display defects such as light leakage.
[0036]
[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS.
FIG. 5 is a plan view of the liquid crystal display device according to the present embodiment, and FIG. 6 is a sectional view taken along line AA of FIG. In the liquid crystal display device of the present embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description will be omitted.
[0037]
In the case of the present embodiment, as shown in FIG. 5, a substantially rectangular slit-shaped opening 9s is formed in the pixel electrode 9 on the TFT array substrate 10 side in a plan view. A slit-shaped opening 31s that is linear in a plan view is formed. An opening 9s provided in the pixel electrode 9 is provided on the inclined surface 21a of the insulating film 21, and a connecting portion 9c is provided at a corner of the opening 9s. The opening 31s provided in the common electrode 31 is provided in the transmissive display area. And, by the effect of the openings 9 s and 31 s, the configuration is such that the alignment control force of the liquid crystal is enhanced.
The other configuration is the same as that of the first embodiment, and the description is omitted.
[0038]
Therefore, also in the liquid crystal display device of the present embodiment, similar to the first embodiment, display with high contrast and a wide viewing angle can be realized without display defects such as light leakage.
[0039]
[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a sectional view showing the liquid crystal display device of the present embodiment. Since the basic configuration of the liquid crystal display device of the present embodiment is completely the same as that of the third embodiment, the same reference numerals are given to the same components in FIG. 7 as those in FIG. 6, and the detailed description will be omitted. .
[0040]
In this embodiment, instead of providing the common electrode 31 with a slit-shaped opening 31s in the third embodiment shown in FIG. 6, a triangular ridge (convex portion) is formed at the center of the common electrode 31. ) 31t is formed. Then, an alignment film 33 is formed so as to cover the ridge 31t and the common electrode 31.
The other configuration is the same as that of the third embodiment, and the description is omitted.
[0041]
According to the liquid crystal display device of the present embodiment, it is possible to control the alignment direction of the liquid crystal molecules 50b by the action of the opening 9s of the pixel electrode 9 and the ridge 31t protruding into the liquid crystal layer 50 from the counter substrate 25 side. it can. Thus, display with high contrast and a wide viewing angle can be realized without display defects such as light leakage.
[0042]
[Fifth Embodiment]
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG.
FIG. 8 is a plan view of the liquid crystal display device of the present embodiment. In the liquid crystal display device of the present embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description will be omitted.
[0043]
In the present embodiment, the position of the connecting portion 31c of the opening 31s in the first embodiment is modified. That is, in the present embodiment, the connecting portion 31c is provided near the corner on the long side of the opening 31s, and the connecting portion 31c has a slit width W (for example, 10 μm) at the long side end. From the width L. Note that the width L of the connecting portion is set to 以下 or less of the length L0 (for example, 180 μm) of the edge of the electrode portion inside the opening 31s. By setting the width L in such a range, the liquid crystal molecules in the vicinity of the connection portion 31c can exert an alignment control force not only from the liquid crystal molecules on the long side of the opening but also from the liquid crystal molecules on the short side. .
The other configuration is the same as that of the first embodiment, and the description is omitted.
Therefore, also in the present embodiment, display with high contrast and a wide viewing angle can be realized without display defects such as light leakage.
[0044]
[Sixth Embodiment]
Hereinafter, a sixth embodiment of the present invention will be described with reference to FIG.
FIG. 9 is a plan view of the liquid crystal display device of the present embodiment. In the liquid crystal display device of the present embodiment, the same components as those of the above-described third embodiment are denoted by the same reference numerals, and detailed description is omitted.
[0045]
In the present embodiment, the position of the connecting portion 9c of the opening 9s in the third embodiment is modified. That is, in this embodiment, the connecting portion 9c is provided on the long side near the corner of the opening 9s, and the connecting portion 9c is shifted from the position having the slit width W 'at the end of the long side. L '. Note that the width L 'is set to be equal to or less than 1/4 of the length L0' of the side of the electrode portion inside the opening 9s. By setting the width L 'in such a range, the liquid crystal molecules in the vicinity of the connecting portion 9c can exert an alignment control force not only from the liquid crystal molecules on the long side of the opening but also from the liquid crystal molecules on the short side. it can.
The other configuration is the same as that of the third embodiment, and the description is omitted.
Therefore, also in the present embodiment, display with high contrast and a wide viewing angle can be realized without display defects such as light leakage.
[0046]
[Electronics]
Next, a specific example of an electronic apparatus including the liquid crystal display device according to the above embodiment of the present invention will be described.
FIG. 10 is a perspective view showing an example of a mobile phone. In FIG. 10, reference numeral 500 denotes a mobile phone main body, and reference numeral 501 denotes a display unit using the liquid crystal display device.
Since the electronic device illustrated in FIG. 10 includes the display portion using the liquid crystal display device in any of the above embodiments, the electronic device includes a liquid crystal display portion with a bright, high contrast, and wide viewing angle regardless of the use environment. Equipment can be realized.
[0047]
The technical scope of the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the spirit of the present invention. For example, in the above embodiment, an example in which the present invention is applied to an active matrix type liquid crystal display device using a TFT as a switching element has been described. However, an active matrix type liquid crystal display device using a thin film diode (TFD) switching element, The present invention can also be applied to a passive matrix type liquid crystal display device or the like. In addition, specific descriptions regarding materials, dimensions, shapes, and the like of various components can be appropriately changed.
Further, in the above embodiment, the retardation plates 41 and 42 are configured as a single plate, but may be configured as a laminate of a １ ／ wavelength plate and a 波長 wavelength plate instead. This laminate functions as a broadband circularly polarizing plate, and can make the black display more achromatic. Further, by laminating a negative C plate on this laminate, a wider viewing angle can be achieved. Note that the C plate is a retardation plate having an optical axis in the film thickness direction.
[Brief description of the drawings]
FIG. 1 is an equivalent circuit diagram of a liquid crystal display device according to a first embodiment of the present invention.
FIG. 2 is a plan view showing a configuration of one dot of the liquid crystal display device.
FIG. 3 is a cross-sectional view of the same liquid crystal display device taken along line AA ′ of FIG. 2;
FIG. 4 is a sectional view of a liquid crystal display device according to a second embodiment of the present invention.
FIG. 5 is a plan view of a liquid crystal device according to a third embodiment of the present invention.
FIG. 6 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 7 is a sectional view of a liquid crystal display device according to a fourth embodiment of the present invention.
FIG. 8 is a plan view of a liquid crystal display device according to a fifth embodiment of the present invention.
FIG. 9 is a plan view of a liquid crystal display device according to a sixth embodiment of the present invention.
FIG. 10 is a perspective view illustrating an example of an electronic apparatus according to the invention.
[Explanation of symbols]
9 pixel electrode, 9c connecting part (conductive part), 9s, 31s opening, 9t, 31t convex, 10 TFT array substrate, 20 reflecting film, 21 insulating film (liquid crystal layer thickness adjusting layer) , 21a: inclined surface, 25: counter substrate, 31: common electrode, 31c: connecting part (conductive part), 41, 43: retardation plate (circularly polarized light incidence means), 50: liquid crystal layer, R: reflective display area, T: Transparent display area

Claims (6)

A liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of substrates, and a transmissive display area for performing transmissive display and a reflective display area for performing reflective display are provided in one dot area,
The liquid crystal layer is composed of a liquid crystal having a negative dielectric anisotropy in which an initial alignment state exhibits vertical alignment, and between at least one of the pair of substrates and the liquid crystal layer, the reflective display region and the liquid crystal layer. A liquid crystal layer thickness adjusting layer for making the thickness of the liquid crystal layer different from that of the transmissive display region is provided at least in the reflective display region, and the liquid crystal layer thickness adjusting layer has a boundary between the reflective display region and the transmissive display region. An inclined surface is provided in the vicinity, and electrodes for driving the liquid crystal are provided on inner surfaces of the pair of substrates, respectively, and at least one of the electrodes of the pair of substrates corresponds to the inclined surface. A substantially rectangular slit-shaped opening is provided at the position, and a conducting portion for conducting between the electrode portion inside the opening portion and the outside electrode portion is provided near a corner of the opening portion. LCD screen Apparatus. 2. The liquid crystal display device according to claim 1, wherein the conductive portion is provided at a plurality of corners of the opening. 3. The electrode according to claim 1, wherein the electrode on the side opposite to the electrode provided with the slit-shaped opening is provided with an opening at a position corresponding to substantially the center of the transmissive display area. 4. Liquid crystal display. 3. A projection is provided at a position corresponding to a substantially center of the transmissive display area on an electrode opposite to the electrode provided with the slit-shaped opening. Liquid crystal display device. The liquid crystal display device according to any one of claims 1 to 4, further comprising a substantially circularly polarized light incidence unit for causing substantially circularly polarized light to enter each of the pair of substrates. An electronic apparatus comprising the liquid crystal display device according to claim 1.

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