JP3700585B2 - Color filter substrate, color filter substrate manufacturing method, and liquid crystal display device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display element used for OA equipment such as a personal computer, a word processor, and a monitor display, and a portable information communication equipment, a color filter used therefor, and a manufacturing method thereof.
[0002]
[Prior art]
Originally, since a liquid crystal display element is a light receiving element, there are three types: a transmissive type that requires a light source, a reflective type that uses external light, and a transflective type that has both functions of a reflective type and a transmissive type. In particular, as shown in FIG. 4, a conventional liquid crystal display element in a transflective type has a pair of opposing transparent substrates 1a and 1b each having a transparent display electrode on the inner side and a film retardation on the outer side. A plate 13a, 13b, a pair of polarizing plates 5a, 5b across the film retardation plates 13a, 13b and transparent substrates 1a, 1b, and a half mirror plate 14 on the opposite side of the incident light are provided to constitute a liquid crystal display element. ing. For color correspondence, a color filter 2 is formed inside the upper transparent substrate 1a. A backlight 8 is installed outside the half mirror plate. In the case of the STN mode, one or two film retardation plates 13 are used, and the arrangement locations are also arranged on the upper side, lower side, or upper and lower sides of the transparent substrates 1a and 1b, and the characteristics required in consideration of retardation and the like. Optimize accordingly. In the case of the TN mode of TFT, the film retardation plate 13 is not required.
[0003]
The half mirror plate 14 used in the conventional configuration is a thin film made of -Ag alloy formed on the polarizing plate 5b, and has a thickness of 50 nm. When such a thin film is used, in the reflection type, the backlight 8 is turned off, the half mirror is handled as a reflection plate, and the display on the liquid crystal panel can be viewed by ambient ambient light. In the transmissive type, when the backlight 8 is turned on, the light amount of the backlight 8 is transmitted through the liquid crystal panel, so that the display on the liquid crystal panel can be seen. In this way, by taking advantage of the characteristics of the half mirror 14, it is possible to use both a reflection type and a transmission type.
[0004]
[Problems to be solved by the invention]
However, in the conventional transflective liquid crystal panel, since the reflecting plate has transparency, when used as a transmissive type, the black level floats and the contrast is lowered, and a clear display cannot be obtained. Further, when used as a reflection type, there is a problem that a sufficient reflectance for obtaining a bright display cannot be obtained.
[0005]
Therefore, the above problem can be solved by providing a transmissive part and a reflective part in one pixel of the liquid crystal panel. However, when the color filter layers are all the same thickness, the display characteristics caused by the different transmissive thickness are not satisfactory. was there.
[0006]
[Means for Solving the Problems]
In order to achieve this object, according to the present invention, a color filter layer of a plurality of colors is arranged in a specific pattern on one of a pair of opposing substrates on which a liquid crystal is sandwiched, and the other substrate Is a liquid crystal display element in which a reflective portion that reflects external light and a transmissive portion that transmits backlight light are formed in a pixel unit, and the color filter layer is formed on the reflective portion in each color. and one reflection opposing filter portion facing consists of a single transparent opposing filter portion opposed to said transparent portion, the thickness of the reflective face filter portion thinner than the thickness of the transparent opposing filter portion and, adjacent The adjacent portion of the color filter layers of matching colors is a liquid crystal display in which the reflection facing filter portion and the transmission facing filter portion of adjacent colors are adjacent to each other It is a child.
[0016]
With such a configuration, a color filter can be easily manufactured, and a liquid crystal display element that is bright, has good contrast, and has color reproducibility can be obtained by using the color filter.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a liquid crystal display device and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the drawings.
[0018]
(Embodiment 1)
FIG. 1 is a configuration diagram of a transflective liquid crystal display element. First, a color filter 2 made of red (R), green (G), and blue (B) is formed inside the transparent substrate 1a. The color may be yellow (Y), cyan (C), magenta (M), and is composed of a plurality of colors. Further, as shown in FIG. 1, one pixel is made up of a transmission part 3 and a reflection part 4. The transmissive portion 3 has the same configuration as a conventional transmissive liquid crystal panel. From the display side, the polarizing plate 5a, the transparent substrate 1a, the color filter 2a, the transparent electrode 6a, the liquid crystal layer 7, the transparent electrode 6b, the transparent substrate 1b, and the polarization It becomes the order of the board 5b. From the outside, the light irradiated by the backlight 8 passes through the transmission part 3 and is emitted to the display side, and characters and images are displayed by switching the shutter function of the liquid crystal layer 7.
[0019]
On the other hand, the configuration of the reflective portion 4 of the same pixel is composed of a polarizing plate 5a, a color filter 2b, a transparent electrode 6a, a liquid crystal layer 7, a reflective electrode 9, a scattering shape film 10, and a transparent substrate 1b from the display side. Light rays irradiated from the display side pass through the liquid crystal layer 7 of the reflection part 4 of the liquid crystal panel, are reflected by the reflective electrode 9, pass through the original liquid crystal layer 7 and pass through the second transparent electrode 6a and the color filter 2b. To do. At that time, characters and images can be displayed by switching the liquid crystal layer 7.
[0020]
As shown in FIG. 2, the number of times of passing through the color filter 2 is two for the reflection unit 4 and one for the transmission unit 3. However, since the density of the two color filters 2 is the same, the reflection portion 4 is dark and the transmission portion 3 is thin. In the present invention, in order to solve this problem, the thickness of the color filter 2 of the transmissive portion 3 is designed to be thicker than that of the reflective portion 4. Ideally, it is appropriate that the transmissive part 3 is twice as thick as the reflective part 4. Further, this method may be applied to all colors used in the color filter 2.
[0021]
Moreover, the scattering shape film | membrane 10 described in FIG. 1 may be located also in the permeation | transmission part 3, when it has permeability | transmittance. Further, even when the forward scattering film 10 as shown in FIG. 3 is used, when the pixel is divided into the transmission part 3 and the reflection part 4, the configuration of the color filter 2 is the same as described above, the reflection part 4 is thin, and the transmission part 3 Should be thicker. In other configurations, even when the scattering film 10 is provided inside the color filter 2 or the scattering function is included in the color filter 2 itself, the thickness of the color filter 2 is thin in the reflection portion 4 and thick in the transmission portion 3. Good.
[0022]
Next, the liquid crystal mode will be a passive matrix such as STN or TN, but even if it is an active matrix such as TFT or MIM (TFD), if the above configuration is used, it will be a transflective liquid crystal panel. can do.
[0023]
As described above, in the present invention, two or more different pixels are formed in each pixel of the color filter 2, and one pixel is divided into the reflective portion 4 and the transmissive portion 3 to form a transflective liquid crystal panel. In this case, the reflective part 4 is used to make the color filter 2 thinner and the transmissive part 3 is made thicker. As a result, the light beam that passes through the liquid crystal layer 7 passes through the color filter 2 twice in the reflection unit 4 and passes through the transmission unit 3 once. Therefore, when the color filter 2 of the same density is used, each of reflection and transmission is performed. The color reproducibility will be enhanced.
[0024]
(Embodiment 2)
Next, a method for manufacturing the color filter 2 having two or more different film thicknesses in one pixel as described above will be described.
[0025]
Hereinafter, a transparent substrate 1a having a color filter 2 used for a liquid crystal display element according to an embodiment of the present invention will be described with reference to FIG.
[0026]
First, as shown in FIG. 3A, a method of forming a BM (black matrix) 11 on a glass substrate 1a includes a type in which a chromium film is formed in advance and formed by etching, and a pigment-dispersed resin black resist. Or by laminating a colored film in which a pigment-dispersed resin black resist is previously applied to the film, and then patterning the resin BM11 having the required pattern shape by exposure and development. There is a type to ning. Although what is necessary is just to use properly according to the use of a liquid crystal panel, the example using 1-2 micrometers resin BM is demonstrated this time.
[0027]
Next, as shown in FIG. 3B, RGB (R2a, 2b, G2a, G2b, B2a, B2b), which are color filters having different film thicknesses in one pixel, are respectively formed on the BM with a pigment resist film. A method of forming a predetermined pattern by exposing and developing after formation will be described. The film thickness of the colored film is adjusted so that the film thickness of the colored film is 0.5 to 2 μm after completion.
[0028]
As shown in FIG. 3C, exposure is performed using a photomask 12. In the photomask 12 used at this time, the red (R) in-pixel transmission portion of the color filter that becomes the transmission portion of the pixel is set to the total transmission 12a, and the in-pixel reflection portion 4 of the color filter R that becomes the reflection portion of the pixel is Halftone 12b was obtained. The other areas were blanks 12c. The pattern shape of the half-tone region 12b is such that the chrome film of the mask uses a fine pattern such as a slit pattern, a line pattern, a hole pattern, a dot pattern, etc. of about 5 μm, or a chrome film. It is formed by reducing the thickness of the film and designing it so as to be variable according to the exposure amount. The exposure amount at this time is determined by the film thickness for forming the color filter R2 and the sensitivity of the photosensitive resin film R2. Thereafter, development was performed to form pixels with different thicknesses of the color filter R2. In the halftone 12b, the color filter R2b has a thin film thickness, and becomes the reflection portion 4. Further, the blank 12c becomes the color filter R2a, has a large film thickness, and forms the transmission part 3. The difference in film thickness between the two is about twice. In this procedure, other colors, green (G) and blue (B), are repeatedly formed.
[0029]
Finally, as shown in FIG. 1 (d), ITO is formed in a required pattern shape and a desired film thickness on this substrate.
[0030]
【The invention's effect】
As described above, according to the present invention, a color filter can be easily obtained, and by using the color filter, a bright liquid crystal display element with good contrast and color reproducibility can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a liquid crystal display element according to an embodiment of the present invention. FIG. 2 is a conceptual diagram of an embodiment of the present invention. Cross section of display element 【Explanation of symbols】
1a, 1b Transparent substrate 2, 2a, 2b Color filter 3 Transmission type 4 Reflection type 6, 6a, 6b Transparent electrode 9 Reflecting plate 10 Scattering film

Claims (1)

A pixel array of a plurality of color filter layers is arranged in a specific pattern on one of a pair of opposing substrates between which a liquid crystal is sandwiched, and the other substrate has external light in a pixel unit. A liquid crystal display element in which a reflective part that reflects light and a transmissive part that transmits backlight light are formed ,
The color filter layer in each color, and one reflector facing the filter portion opposed to the reflective portion, consists of a single transparent opposing filter portion opposed to said transparent portion, the thickness of the reflective face filter portion the transmission It is thinner than the thickness of the counter filter part,
In addition, the adjacent portion of the color filter layers of adjacent colors is a liquid crystal display element in which the reflection facing filter portion and the transmission facing filter portion of adjacent colors are adjacent to each other .

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