JP4733263B2 - Color liquid crystal display element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color liquid crystal display element, and more specifically to a color liquid crystal display element having an inner surface black mask (light shielding film) in a non-display area.
[0002]
[Prior art]
Referring to FIG. 3, the color liquid crystal display element includes a pair of transparent electrode substrates 1 and 2 which are bonded to each other with a peripheral sealing material 3 as a basic structure. In the case of a reflective type, a light reflecting film (not shown) is formed on the transparent electrode substrate 1 on the back side, and in the case of a semi-transmissive reflective type, a semi-transmissive reflective film is formed on the transparent electrode substrate 1, and a color filter 4 is provided thereon. It is done.
[0003]
When the liquid crystal layer L sandwiched between the transparent electrode substrates 1 and 2 is a super twisted nematic (STN) having a twist of 180 to 270 degrees between the substrates, ITO (indium tin oxide) is formed on the color filter 4. ) To pattern the transparent electrode 6, and the allowable range of the cell gap is particularly narrow, so that the color filter 4 and the transparent electrode 6 are smoothed for the purpose of protecting and smoothing the color filter 4. A layer 5 is provided.
[0004]
A transparent electrode 8 is formed as a counter electrode of the transparent electrode 6 on the transparent electrode substrate 2 on the display observation surface side, which is called an F plate, and the transparent electrodes 6 and 8 and the color filter 4 are displayed on the panel surface. The display area VA is provided in the area VA, and the display area VA is a non-display area VB for forming the wiring lines for the transparent electrodes 6 and 8.
[0005]
The non-display area VB is a portion that is not originally involved in display. However, if the cell gap is different between the display area VA and the non-display area VB, that is, if the retardation Δn · d is different, display unevenness is caused in the peripheral portion of the display area VA. Will occur.
[0006]
In order to prevent this, the cell gap may be made uniform over the entire range of the display area VA and the non-display area VB. As one of the methods, it is conceivable to form the color filter 4 having the same pixel configuration as that of the display area VA in the non-display area VB. In either case, there is a problem that uneven brightness occurs in the peripheral portion of the display area VA, and this method cannot be employed.
[0007]
[Problems to be solved by the invention]
Therefore, conventionally, a black mask 9 having substantially the same thickness as the color filter 4 is formed in the non-display area VB so that the cell gap is uniform over the entire range of the display area VA and the non-display area VB. However, this has the following problems.
[0008]
The color filter 4 includes B, R, and G color elements, and is formed by a pigment dispersion method, a dyeing method, a printing method, an electrodeposition method, or the like based on a photolithography technique. As a typical example, according to the pigment dispersion method, negative color photoresist liquid application → pre-baking → pattern exposure → development → post-baking is repeated for B, R, and G3 colors to obtain B, R, and G3 colors. A filter is formed.
[0009]
The current photolithographic technology has a high definition of the order of 1 to 2 μm. However, when forming each color element of B, R, and G without gaps, it depends on the accuracy of the plate, the thermal expansion of the plate and the substrate at the time of exposure. As shown in FIG. 3, a bowl-shaped overlapping portion 4a is formed between adjacent color elements.
[0010]
If such an overlapping portion 4a exists in the display area VA, the cell gap in the display area VA and the cell gap in the non-display area VB are different from each other on average, and the periphery of the display area VA still remains. Display unevenness occurs in the part. Incidentally, in the case of the STN method, display unevenness occurs even if the cell gap is different by 0.1 μm.
[0011]
[Means for Solving the Problems]
According to the present invention, in a color liquid crystal display element in which a black mask having substantially the same thickness as a color filter is formed in a non-display area, the cell gap can be made uniform over the entire range of the display area and the non-display area.
[0012]
That is, the present invention includes a pair of transparent electrode substrates that are bonded to each other via a peripheral sealing material and the display form of the display area is a full dot display, and the display area of the one transparent electrode substrate includes R , G, and B are provided with a color filter formed in stripes corresponding to one of the row electrode or the column electrode, and the non-display area around the display area includes the color filter. A super twisted nematic color liquid crystal display element in which a black mask having the same thickness as the filter is formed, a liquid crystal layer sandwiched between the transparent electrode substrates is a nematic liquid crystal, and a twist angle between the substrates is 180 to 270 degrees However, there is no black stripe between the color elements in the display area, and there is an overlapped part that directly overlaps, and the blur in the non-display area is present. On Kkumasuku, it is characterized in that ribs having overlapping portions of the same width and the same protruding height of each of the color elements are formed substantially parallel to the above-described color element.
[0013]
In this case, on the black mask positioned on both ends of each color element in the stripe direction, the rib is preferably disposed on the extension line of the center of each color element from the viewpoint of uniform cell gap, Further, an interval of about one pixel may be placed between the rib and the edge of each color element. On the other hand, from the viewpoint of manufacturing, it is preferable from the viewpoint of reducing the number of steps and the number of plates that the ribs are formed of the same material as the color elements.
[0014]
The present invention is preferably applicable to a transflective color liquid crystal display element. That is, the transflective film, which is an essential component of this type of display element, is usually provided in the plane of the liquid crystal cell from the viewpoint of preventing parallax, but it is unlike the mask sputtering method in which the positional accuracy is insufficient for its formation. When a region without a semi-transmissive reflective film is generated in the cell plane using such means, significant luminance unevenness occurs based on the difference in transmittance and reflectance from the region with the film. The difference between the transmittance and the reflectance is concealed by the black mask provided in the non-display area, and the occurrence of luminance unevenness is effectively prevented, and the aperture ratio is increased because there is no black mask in the display area. High luminance display is possible.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the cross-sectional view of FIG. 1 and the schematic plan view of the main part of FIG. In this embodiment, the same reference numerals are used for components that may be regarded as the same as or the same as those of the conventional example of FIG. 3 described above.
[0016]
First, the display form of the color liquid crystal display element according to the present invention is a full dot display. That is, if the transparent electrode 6 formed on the back side transparent electrode substrate (R plate) 1 side is, for example, a striped row electrode (X electrode), the transparent electrode substrate (F plate) on the display observation surface side. The transparent electrode 8 formed on the second side is a striped column electrode (Y electrode) orthogonal to the row electrode.
[0017]
In this embodiment, the element is of a transflective type so that each color element B, R, G of the color filter 4 is along the side of the transparent electrode 8 that is a column electrode on the transflective film provided on the R plate. Are formed in stripes. The color filter 4 is formed by, for example, a pigment dispersion method, and there is no black stripe between adjacent color elements, and there is a bowl-shaped overlapping portion 4a in which the color elements directly overlap each other. The width of the overlapping portion 4a is about 10 μm.
[0018]
In the non-display area VB, a black mask 9 is formed with a thickness substantially the same as the thickness of the color filter 4, and the periphery of the transflective film is positioned below the black mask 9. An overlapping portion 4a also exists between the black mask 9 and the color element adjacent thereto.
[0019]
In order to eliminate the non-uniformity of the cell gap between the display portion VA and the non-display portion VB due to the overlap portion 4a, in the present invention, ribs 11 and 12 similar to the overlap portion 4a are provided also in the non-display portion VB.
[0020]
As shown in FIG. 2, even in the non-display portion VB, the non-display portion VB1 located on both sides (left and right sides in FIG. 2) in the direction in which the color elements B, R, and G are adjacently arranged, and each color element The non-display portion VB2 located on both ends in the stripe direction of B, R, and G (upper and lower sides in FIG. 2) is different in the manner of rib arrangement.
[0021]
That is, on the black mask 9 of the non-display portion VB1, a plurality of ribs 11 are arranged in parallel with the color elements B, R, G and at the same arrangement pitch. On the other hand, on the black mask 9 of the non-display portion VB2, a plurality of ribs 12 are arranged on the extension lines of the centers of the color elements B, R, and G.
[0022]
In this embodiment, both the ribs 11 and 12 have the same width (about 10 μm) and the same protruding height (about 1 μm) as the overlapping portion 4 a of the color filter 4 by the same negative color photoresist as that when forming the color filter 4. It is formed. For the rib 12 on the non-display portion VB2 side, an interval W (for example, about one pixel) is provided between the rib 12 and the edge of each color element B, R, G in order to correct the area distribution. 70 μm).
[0023]
The smoothing layer 5 is provided on the color filter 4 and the black mask 9, and the transparent electrode 6 is formed thereon. The ribs 11 and 12 corresponding to the overlapping portion 4 a of the color filter 4 are also formed on the black mask 9. Therefore, the cell gap can be made uniform over the entire range of the display area VA and the non-display area VB, and display unevenness around the display area VA is eliminated.
[0024]
In order to make the width of the overlapping portion 4a of the color filter 4 (including the overlapping portion of the color elements and the overlapping portion of the color element and the black mask) less susceptible to variations in development accuracy, the width is about 10 μm. And relatively wide.
[0025]
【The invention's effect】
As described above, according to the present invention, in a color liquid crystal display element in which a black mask having substantially the same thickness as a color filter is formed in a non-display area, each color element is formed on the black mask in the non-display area. By forming ribs having the same width as the overlapping portion and the same protruding height in parallel with the respective color elements, the cell gap can be made uniform over the entire range of the display area and the non-display area. In addition, since there are no black stripes in the display area, the aperture ratio is increased, and high luminance display is achieved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a part of a color liquid crystal display element according to an embodiment of the present invention.
FIG. 2 is a schematic plan view showing an enlarged main part of the present invention.
FIG. 3 is a cross-sectional view showing a part of a color liquid crystal display element according to a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 2 Transparent electrode substrate 3 Peripheral sealing material 4 Color filter 4a Overlapping part 5 Smoothing layer 6, 8 Transparent electrode 9 Black mask 11, 12 Rib L Liquid crystal layer VA Display area VB Non-display area R, G, B Color element

Claims (4)

It includes a pair of transparent electrode substrates that are bonded to each other with a peripheral sealing material and the display form of the display area is full-dot display. The display area of the one transparent electrode substrate includes R, G, and B A color filter in which color elements are formed in a stripe shape corresponding to one of the row electrode or the column electrode is provided, and a non-display area around the display area has substantially the same thickness as the color filter. In a super twisted nematic color liquid crystal display element in which a black mask is formed, a liquid crystal layer sandwiched between the transparent electrode substrates is a nematic liquid crystal, and a twist angle between the substrates is 180 to 270 degrees.
There is no black stripe between the color elements in the display area, and there is an overlapping part that directly overlaps, and the same width and the same width as the overlapping part of the color elements on the black mask in the non-display area. A color liquid crystal display element, wherein a rib having a protruding height is formed substantially parallel to each of the color elements. 2. The color liquid crystal display element according to claim 1, wherein the rib is disposed on an extension line of the center of each color element on the black mask positioned at both ends of each color element in the stripe direction. 3. The color liquid crystal display element according to claim 2, wherein the rib is separated by about one pixel from the edge of each color element. 4. The color liquid crystal display element according to claim 1, wherein the rib is made of the same material as the color elements.

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