JP2004093780A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transflective color liquid crystal display capable of obtaining chromaticities different between a reflection display region and a transmission display region in one pixel region and obtaining bright display. <P>SOLUTION: In the transflective liquid crystal display provided with a pair of substrates 20A and 30A disposed opposite to each other and a liquid crystal layer 50 interposed between a pair of the substrates, wherein the reflection display region 33 and the transmission display region 34 are formed in the one pixel region and a reflection layer 35 is formed in the reflection display region, a first color filter( a first color material layer) 48 and a second color filter (a second color material layer) 42 sandwiching the liquid crystal layer are provided on both sides of the liquid crystal layer. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transflective color liquid crystal display device.
[0002]
[Prior art]
As a transflective liquid crystal display device, there is known a liquid crystal display device in which a reflective display region is formed by partially forming a reflective layer in one pixel region, and the remaining light transmissive region is used as a transmissive display region. I have. In this type of liquid crystal display device, a color display can be performed by providing a color filter on one of the two substrates constituting the liquid crystal display device. Due to the difference in the method, the number of times light emitted from the light source passes through the color filter while arriving at the observer is different.If a common color filter is used in the two regions, the chromaticity of the transmissive display is changed to the reflective display. Problems such as inferior or dark reflective display occur.
[0003]
[Problems to be solved by the invention]
Therefore, it is conceivable to form a color material layer for transmissive display and a color material layer for reflective display in a color filter in one pixel area in each area so as to make chromaticity of transmissive display and reflective display uniform. Can be In the case of manufacturing such a color filter, it is necessary to form the two types of color material layers without gaps in the pixel region, and extremely high-precision manufacturing technology is required. Therefore, usually, the two color material layers are formed so as to partially overlap each other at the boundary between the two color material layers, and the layer thickness of the color filter becomes large at that portion. This is liable to cause disturbance, which causes a decrease in display of high contrast. In some cases, it is necessary to form a light-shielding layer (black mask) along the boundary between the two color material layers, which causes a problem that the aperture ratio is reduced.
[0004]
The present invention has been made to solve the above-mentioned problem, and a transflective type in which a different chromaticity is obtained between a reflective display area and a transmissive display area in one pixel area and a bright display is obtained. It is an object of the present invention to provide a color liquid crystal display device.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention includes a pair of substrates disposed to face each other, and a liquid crystal layer sandwiched between the pair of substrates. A transflective liquid crystal display device having a display region and a reflective layer in the reflective display region, wherein the first color material layer and the second color material layer are disposed on both sides of the liquid crystal layer. And a color material layer.
According to the above configuration, a liquid crystal display device having a plurality of chromaticities in one pixel region can be easily configured by the first color material layer and the second color material layer. That is, unlike the case where the color material for the reflective display and the color material for the transmissive display are formed on the same substrate, there is no need to consider butting and overlapping of the two color materials. The rate is prevented from lowering, and a bright display is obtained.
[0006]
Next, in the liquid crystal display device of the present invention, the first color material layer is formed in a plane region including the reflective display region, and the second color material layer is formed in a plane region including the transmissive display region. The pixel region may be configured to have a region in the pixel region where the two color material layers partially overlap in a plan view.
According to the above configuration, in the reflective display area, color display is performed mainly through the first color material layer, and in the transmissive display area, color display is mainly performed through the second color material layer. Thus, a liquid crystal display device configured to perform color display or a configuration configured to perform color display via the first color material layer and the second color material layer in one or both of the reflective display region and the transmissive display region is obtained. In these liquid crystal display devices, the first and second color material layers have a region that partially overlaps in plan view, so that the color material layers are naturally abutted at the edge of this region. . In addition, since the two color material layers are not superimposed on the same substrate, unevenness in the thickness of the liquid crystal layer may occur due to these color material layers while providing a plurality of color material layers in the pixel region. Absent. Therefore, according to such a configuration, it is possible to easily obtain a liquid crystal display device having different chromaticities between the reflective display and the transmissive display and having excellent display quality.
[0007]
Next, the liquid crystal display device of the present invention has an inclined region in which the thickness of the liquid crystal layer changes continuously between the transmissive display region and the reflective display region. A configuration may be adopted in which the inclined region is included in a region where the layer and the second color material layer overlap in a plane.
The liquid crystal display device having the above configuration has a configuration in which the transmissive display region and the reflective display region have different liquid crystal layer thicknesses, and a displacement region of both liquid crystal layer thicknesses is the inclined region. . This inclined region is not suitable for display because the thickness of the liquid crystal layer is not constant. In the liquid crystal display device having this configuration, the first color material layer and the second color material layer are planarly overlapped with each other so that the region in which light is hardly transmitted includes the inclined region. With the arrangement, the amount of light transmitted through the inclined region can be suppressed as much as possible, thereby suppressing a decrease in display contrast.
[0008]
Next, the liquid crystal display device of the present invention has a configuration in which the edge of the first color material layer on the transmission display area side is substantially the same as the edge of the inclined area on the transmission display area side in plan view. You can also.
According to the above configuration, the first color material layer, which mainly functions as a color material layer for reflective display, does not overlap the second color material layer in a planar manner in the transmissive display area, and the tilt becomes a display defective portion. Since the area is formed so as to cover, it is possible to suppress the amount of light transmission in the inclined area without affecting the chromaticity and aperture ratio of the transmissive display area. That is, since the color display of the transmissive display area is performed using only the second color material layer, the chromaticity of the transmissive display area can be set more accurately.
[0009]
Next, the liquid crystal display device of the present invention has a configuration in which the edge of the second color material layer on the reflective display area side is substantially the same as the edge of the inclined area on the reflective display area side in plan view. You can also.
According to the above configuration, the second color material layer, which mainly functions as a color material layer for transmissive display, does not overlap the first color material layer in the reflective display area in a planar manner, and becomes a display failure portion. Since the area is formed so as to cover, it is possible to suppress the amount of light transmission in the inclined area without affecting the chromaticity and the aperture ratio of the reflective display area. That is, since the color display of the transmissive display area is performed only with the first color material layer, the chromaticity of the transmissive display area can be set more accurately.
In addition, by combining with the arrangement of the edge of the first color material layer, the chromaticity of the transmissive display and the reflective display can be set independently and arbitrarily.
[0010]
Next, the liquid crystal display device of the present invention may have a configuration in which the first color material layer is formed over the entire surface of the pixel region.
According to the above configuration, the display of different chromaticities is performed in a region where the first color material layer and the second color material layer overlap in a plane and in a plane region where only the first color material layer is provided. A possible liquid crystal display device is obtained. Then, if the first color material layer is formed in a region including a reflective display region and the second color material layer is formed in a region including a transmissive display region, the first color material layer and the first color material layer are formed. An area where the second color material layer overlaps in a plane functions as a color material layer for transmissive display, and a plane area in which only the first color material layer is provided functions as a color material layer for reflective display. A liquid crystal display device can be configured. With such a configuration, since the edge of the second color material layer coincides with the boundary between the regions having different chromaticities, it is not necessary to consider the butting between the regions having different chromaticities. Since the color material layer can be formed, the ease of manufacturing the liquid crystal display device can be improved.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(1st Embodiment)
FIG. 1 is a circuit configuration diagram showing a wiring structure in a plurality of pixels formed in a matrix forming an active matrix type liquid crystal display device according to a first embodiment of the present invention, and FIG. 3 is a partial cross-sectional structural view taken along line AA shown in FIG. 2. FIG. As shown in FIGS. 2 and 3, the liquid crystal display device of this embodiment has a reflective display area 33 and a transmissive display area 34 in one pixel area, and an inclined area between the display areas 33 and 34. This is a transflective liquid crystal display device including a liquid crystal panel 1 having a liquid crystal panel 18 and a backlight (illumination device) 2 disposed on the back side thereof.
[0012]
As shown in FIG. 1, the liquid crystal display device according to the present embodiment includes a plurality of scanning lines 11, a plurality of data lines 12 extending in a direction intersecting the scanning lines 11, and a capacitance extending in parallel with each scanning line 11. Each of the lines 13 is wired, and a pixel region 10 is provided near each intersection of the scanning line 11 and the data line 12. In each of the pixel regions 10, a pixel electrode 23 and a TFT element 22 as a pixel switching element are formed, and a data line 12 to which an image signal is supplied is electrically connected to a source region of the TFT element 22. ing. The scanning line 11 is electrically connected to the gate electrode of the TFT element 22. The pixel electrode 23 is electrically connected to the drain of the TFT element 22. By switching the TFT element 22 according to the scanning signal supplied from the scanning line 11, the image signal supplied from the data line 12 is switched to a predetermined voltage. At this timing, writing is performed on the pixel electrode 23, and an image signal is held between the pixel electrode 23 and the opposing electrode with the liquid crystal layer interposed therebetween. In order to prevent the image signal written to the pixel electrode 23 from leaking, a storage capacitor 17 is added in parallel with the pixel electrode 23, and one electrode of the storage capacitor 17 is connected to the capacitor line 13. It is electrically connected.
[0013]
Next, a detailed configuration of the pixel region 10 shown in FIG. 1 will be described with reference to FIGS.
As shown in FIG. 2, in the pixel region 10, a translucent pixel electrode 23 having a rectangular shape in a plan view and a reflection layer 35 are formed so as to overlap a part of the pixel electrode 23 in a plane. . The area in which the reflective layer 35 is formed is a reflective display area 33, and the transmissive display area 34 on the upper side of the reflective display area 33 is a light transmitting area in the area in which the pixel electrode 23 is formed. Have been. A rectangular electrode portion 26 constituting the capacitance line 13 is formed below the reflective layer 35, and is disposed to face the rectangular capacitance electrode 27 formed below the electrode portion 26, and has a storage capacitance. 17. In plan view, the electrode portion 26 partially protrudes toward the transmissive display region 34 from the reflective layer 35, and the capacitor electrode 27 partially protrudes further from the electrode portion 26 toward the transmissive display region 34. . Then, in plan view, a region between the reflective display region 33 and the transmissive display region 34 corresponds to the inclined region 18.
[0014]
In the pixel region 10, the data line 12 and the scanning line 11 are provided along the vertical and horizontal boundaries of the pixel electrode 23, and the TFT element 22 is formed near the intersection of the data line 12 and the scanning line 11. Have been. The TFT element 22 is formed in a substantially U-shaped TFT forming portion 24 as a part of the semiconductor layer, and a rectangular capacitor electrode 27 extends at one end of the U-shaped TFT forming portion 24. And constitutes a semiconductor layer together with the TFT forming section 24.
The TFT element 22 according to the present embodiment includes a double-gate TFT element in which channel regions 22a and 22b are formed at two locations where a substantially U-shaped TFT forming portion 24 and a scanning line 11 intersect in a plan view. Have been. A contact hole 25 is formed at the tip of one arm portion along the data line 12 of the TFT forming portion 24, and the data line 12 and the source side of the TFT element 25 are electrically connected via the contact hole 25. . The tip side of the arm of the TFT forming portion 24 opposite to the contact hole 25 is the drain side of the TFT element 24. A contact hole 40 is formed in the center of the lower end of the capacitor electrode 27 in the figure, and the relay electrode 37 formed in a layer between the reflective layer 35 and the capacitor electrode 27 via the contact hole 40 forms a capacitor electrode. 27 are electrically connected. The pixel electrode 23 is electrically connected to the relay layer 37 via a contact hole 41. The drain of the TFT element 22 and the pixel electrode 23 are electrically connected to each other via the contact holes 40 and 41 and the relay layer 37. It is connected to the. The plane area of the relay layer 37 including the contact holes 40 and 41 is formed so as to overlap the plane area of the rectangular opening 35 a provided in the reflection layer 35.
[0015]
On the other hand, in the cross-sectional configuration diagram shown in FIG. 3, the liquid crystal display device of the present embodiment includes an array substrate 20, a counter substrate 30, and a liquid crystal layer 50 sandwiched between these substrates 20 and 30. And a backlight 2 arranged on the outer surface side of the lower substrate 20 of the liquid crystal panel 1. The array substrate 20 has a transparent substrate 20A made of glass, plastic, resin film, or the like.
On the inner surface side (the liquid crystal layer 50 side) of the substrate 20A, a capacitor electrode 27, a first interlayer insulating film 45 covering the capacitor electrode 27, an electrode part 26 (and the scanning line 11), and a second part covering the electrode part 26. An interlayer insulating film 46, a relay layer 37, a third interlayer insulating film 47 covering the relay layer 37, a reflective layer 35 and a second color filter (second color material layer) 42, and the reflective layer 35 and the second And a pixel electrode 23 that covers the color filter 42.
[0016]
The capacitor electrode 27 and the electrode section 26 are arranged to face each other in the vertical direction of the liquid crystal panel, and form the storage capacitor 17 using the first interlayer insulating film 45 as an insulating layer. The relay layer 37 is electrically connected to the capacitor electrode 27 via a contact hole 40 formed through the first interlayer insulating film 45 and the second interlayer insulating film 46. It is electrically connected to the pixel electrode 23 via a contact hole 41 formed through the three interlayer insulating film 47.
[0017]
The reflection layer 35 is formed on the third interlayer insulating film 47 above the electrode section 26, and the second color filter 42 is provided adjacent to the reflection layer 35 and the same layer. The pixel electrode 23 is formed to cover the reflective layer 35 and the second color filter. A plurality of fine concave portions 32 are formed on the surface of the third interlayer insulating film 47 in the region where the reflective layer 35 is formed.
A polarizing plate 21 is provided on the outer surface side of the substrate 20A.
[0018]
The counter substrate 30 has a transparent substrate 30A made of glass, plastic, resin film, or the like, and the inner surface side (the liquid crystal layer 50 side) of the substrate 30A substantially corresponds to the reflective display region 33 and the transmissive display region. A first color filter (first color material layer) 48 is formed in the plane area, and a resin layer 36 is partially provided on the first color filter 48. A counter electrode 38 made of a transparent conductive material such as ITO is provided so as to cover the filter 48. A polarizing plate 39 is provided on the outer surface side of the substrate 30A.
The resin layer 36 is formed at a position corresponding to the reflective display region 33 of the pixel region 10. The resin layer 36 allows the liquid crystal layer thickness dr of the reflective display region 33 and the liquid crystal layer thickness dt of the transmissive display region 34 to be reduced. By adjusting the optical path length in both display areas, high-luminance display can be performed in both reflective display and transmissive display. In addition, the resin layer 36 has an inclined portion 36a inclined at an edge portion with respect to the substrate 30A, and the inclined portion 36a is disposed outside the planar region of the reflective layer 35. In the present specification, a plane area of a portion located between the reflective display area 33 and the transmissive display area 34 in the inclined portion 36 a is defined as the inclined area 18.
Although not shown, an alignment film is provided on the pixel electrode 23 and the counter electrode 38 so as to cover these electrodes.
[0019]
The liquid crystal display device of the present embodiment having the above configuration performs reflection display by reflecting external light by the reflective layer 35 of the reflective display area 33 in an environment where external light can be used, such as bright outdoors, and it is difficult to use external light. In the environment, light emitted from the backlight 2 is transmitted to perform transmissive display.
In the liquid crystal display device described above, the first color filter 48 is provided in a region of the counter substrate 30 including the reflective display region 33 and the transmissive display region 34, and the second color filter is provided in a region of the array substrate 20 including the transmissive display region 34. By providing the color filter 42, color display is performed using the first color filter 48 in the reflective display area 33, and both the first color filter 48 and the second color filter 42 are used in the transmissive display area. Color display. With such a configuration, the chromaticity of the reflective display and the transmissive display is appropriately adjusted, and the planar boundary between the first color filter 48 and the second color filter 42 is , The processing accuracy of the color filter is reduced and the ease of manufacturing is improved as compared with the case where the color filter for reflective display and the color filter for transmissive display are formed on the same substrate. . Therefore, the configuration of the present embodiment is particularly suitable for a high-definition liquid crystal display device in which the pixel region 10 is finer.
[0020]
Further, the second color filter 42 on the array substrate 20 side extends to a position overlapping the inclined region 18 in a plane, and the first color filter 48 and the second color filter 42 are planarly arranged in the inclined region 18. Since the thickness of the liquid crystal layer 50 changes, light becomes relatively difficult to transmit in the inclined area 18 which is not suitable as a display area, and a black mask for covering the inclined area 18 is required. Even without this, it is possible to minimize the decrease in the display contrast, and it is possible to obtain the effect of improving the display luminance by improving the aperture ratio.
[0021]
In the above embodiment, the edge of the second color filter 42 on the side of the reflective display area 33 and the edge of the reflective layer 35 are formed so as to abut each other, and the boundary between the two is formed by the reflective display area 33 of the inclined portion 36a. The description has been given of the case where the edge is substantially the same as the edge in plan view. However, the edge of the second color filter 42 may be formed at least outside the inclined region 18 (on the side of the reflective display region 33). In some cases, a part thereof may be formed so as to overlap a part of the reflection layer 35. Even in such a case, although the chromaticity of the reflective display is slightly affected, the chromaticity of the transmissive display is not affected, and the aperture ratio is not reduced. An indication of the quality can be obtained.
[0022]
(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a plan configuration diagram showing one pixel region in the liquid crystal display device according to the second embodiment of the present invention, and FIG. 5 is a partial cross-sectional configuration diagram taken along line BB shown in FIG. The difference between the liquid crystal display device of this embodiment shown in these figures and the liquid crystal display devices shown in FIGS. 1 to 3 is that the configuration of the first color filter (first color material) provided on the counter substrate 30 is different. Only. Therefore, hereinafter, only the configuration of the color filter will be described in detail, and description overlapping with the first embodiment will be omitted. In FIGS. 4 and 5, the same reference numerals as those shown in FIGS. 1 to 3 indicate the same components.
[0023]
In the liquid crystal display device of the present embodiment, as shown in FIGS. 4 and 5, a first color filter 49 is provided on the inner surface of the substrate 30A in a region corresponding to the reflective display region 33. A layer 36 is formed. A counter electrode 38 is formed on the substrate 30A so as to cover the resin layer 36. The edge of the first color filter 49 and the edge of the resin layer 36 are substantially at the same position in plan view, and the inclined portion 36a formed on the peripheral edge of the resin layer 36 is the same as the liquid crystal of the first embodiment. Like the display device, it is arranged outside the plane area of the reflective layer 35. That is, since the edge of the second color filter 42 on the array substrate 20 side on the reflective display area 33 side and the edge of the reflective layer 35 on the transmissive display area 34 side are formed to face each other, the reflective display area 33 is formed. The first color filter 49 and the second color filter 42 on the side of the array substrate 20 are disposed so as to overlap in a plane in the inclined region 18 which is a plane region of the inclined portion 36 a between the transmissive display regions 34.
[0024]
In the liquid crystal display device according to the present embodiment having the above configuration, as shown in FIGS. 4 and 5, the first color filter 49 and the second color filter 42 are configured to overlap in a plane only in the inclined region 18. Therefore, in the reflective display, color display is performed via the first color filter 49, and in the transmissive display, color display is performed via the second color filter 42. With such a configuration, the chromaticity of the transmissive display and the reflective display can be set independently and arbitrarily, and the degree of freedom of the chromaticity adjustment is improved.
Further, in the inclined region 18, since the first color filter 49 and the second color filter 42 overlap in a plane, the thickness of the liquid crystal layer 50 is changed, so that the inclined region 18 unsuitable as a display region is changed. In this case, light becomes relatively difficult to transmit, and even if a black mask for covering the inclined region 18 is not provided, a decrease in display contrast can be suppressed as much as possible. Can be obtained.
[0025]
In the liquid crystal display device according to the present embodiment, the edge of the first color filter 49 on the transmission display area 34 side is substantially the same as the edge of the resin layer 36 on the transmission display area side in plan view, and The case where the edge of the color filter 42 on the side of the reflective display area 33 and the edge of the reflective layer 35 on the side of the transmissive display area 34 are substantially at the same position in a plan view has been illustrated and described. The edge on the side of the transmissive display area only needs to be arranged at least outside the edge of the resin layer 36 on the side of the transmissive display area, and the edge of the second color filter 42 on the side of the reflective display area 33 is at least an inclined area. It suffices that they are arranged outside (reflective display area side) from the edge of the reflective display area 33 on the 18 side. That is, if the region where the first color filter 49 and the second color filter 42 overlap in a plane includes the inclined region 18 which is the planar region of the inclined portion 36a, the chromaticity of display is slightly affected. In addition, the inclined region 18 can be made hard to be visually recognized without lowering the aperture ratio.
Also in the liquid crystal display device of the present embodiment, since the first color filter 49 and the second color filter 42 are provided on different substrates, the two-dimensional color filter 49, It has the advantage of not affecting the thickness.
[0026]
(Example of application to electronic equipment)
The liquid crystal display device of the above embodiment is an electronic book, a personal computer, a mobile phone, 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, an electronic notebook, a calculator, a word processor. , A workstation, a videophone, a POS terminal, a device equipped with a touch panel, and the like, and any electronic device can provide high-quality color display.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram showing a wiring structure of a liquid crystal display device according to a first embodiment of the present invention.
FIG. 2 is a plan view of one pixel region 10 shown in FIG. 1;
FIG. 3 is a partial sectional structural view taken along line AA shown in FIG. 2;
FIG. 4 is a plan view showing one pixel region according to a second embodiment of the present invention.
FIG. 5 is a partial cross-sectional configuration diagram taken along line BB shown in FIG. 4;
[Explanation of symbols]
10 pixel area, 20A substrate, 30A substrate, 48, 49 First color filter (first color material layer), 42 Second color filter (second color material layer), 35 Reflective layer, 33 Reflective display area, 34 Transparent display area

Claims (6)

A pair of substrates disposed opposite to each other, and a liquid crystal layer sandwiched between the pair of substrates, wherein a reflective display region and a transmissive display region are formed in one pixel region; A transflective liquid crystal display device having a reflective layer,
A liquid crystal display device comprising a first color material layer and a second color material layer provided on both sides of the liquid crystal layer. The first color material layer is formed in a plane area including the reflective display area,
The second color material layer is formed in a plane area including the transmissive display area,
2. The liquid crystal display device according to claim 1, wherein the pixel region includes a region where the two color material layers partially overlap in a plan view. Between the transmissive display area and the reflective display area, the liquid crystal layer has an inclined area in which the thickness of the liquid crystal layer continuously changes,
3. The liquid crystal display device according to claim 2, wherein the inclined region is included in a region where the first color material layer and the second color material layer planarly overlap with each other. 4. 4. The liquid crystal display according to claim 3, wherein an edge of the first color material layer on the transparent display area side is substantially the same as an edge of the inclined area on the transparent display area side in a plan view. 5. apparatus. The edge of the second color material layer on the side of the reflective display area is substantially the same as the edge of the inclined area on the side of the reflective display area in a plan view. Liquid crystal display. The liquid crystal display device according to claim 1, wherein the first color material layer is formed over an entire surface of the pixel region.

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