JPH05181010A - Color filter and production thereof - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose of the present invention is to improve the quality of performance of color filters for liquid crystal display panels and the manufacturing method thereof. [Structure] A large number of color pixels 4 filled in the surface of a black mask 23 formed on a transparent substrate 22 and the through holes of the black mask 23.
The surface of R, 4G, 4B is formed in the same plane. Many color pixels 4
The transparent substrate 22 forming R, 4G, 4B is coated with a black resin film which is harder than the metal film 31 or the pixel forming resin, the thickness required by the pixels 4R, 4G, 4B or thicker than required. .. Then, a black mask 23 with a large number of pixel forming through holes is formed by selective etching of the metal film 31 or the resin film, and after the pixels 4R, 4G, 4B thicker than necessary are sequentially formed in the through holes, The pixels 4R, 4G, 4B are polished to the same thickness as the black mask 23, or the pixels 4R, 4G, 4B and the black mask 23 are polished to a required thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter for a color liquid crystal display panel or the like, and more particularly to a structure for improving display quality.

[0002]

2. Description of the Related Art Liquid crystal display panels, whose demands are expanding for office automation equipment, personal computers, portable televisions, etc., due to their features such as thinness, light weight, and low power consumption, have been popularized in color display. Therefore, in the future, adaptability to new products such as wall-mounted television is expected, and further demand expansion is expected.

In such a color liquid crystal display panel, a color filter including pixels of three colors of red (R), green (G) and blue (B) is formed on a transparent substrate, and the pixels of these three colors are selectively driven. To mix colors and display arbitrary colors.

Coloring of pixels includes a dyeing method in which gelatin or the like is dyed with a dye, and a pigment dispersion method in which a pigment is dispersed in a resin. The color pixels are formed by an electrodeposition method, a printing method,
There are photolithographic methods, but pattern accuracy,
The photolithographic method is most suitable for making the thickness uniform.

FIG. 6 is a schematic sectional view showing the main structure of a conventional color liquid crystal display panel, and FIGS. 7 and 8 are explanatory views of the main manufacturing steps of the color filter for liquid crystal display panel shown in FIG. In FIG. 6, a display panel 1 includes a first glass substrate 2 having a color filter, a first transparent electrode 6 and the like formed on the upper surface, and a second glass substrate 7 having a second transparent electrode 8 and the like formed on the lower surface. The liquid crystal 10 is filled in between.

Reference numeral 11 denotes a liquid crystal filling sealing material, 12 a polarizing plate adhered to the lower surface of the glass substrate 2, 13 a polarizing plate adhered to the upper surface of the glass substrate 8, and a color formed on the upper surface of the glass substrate 2. The filter is formed by forming a black mask 3 and forming a large number of red pixels 4R, green pixels 4G, and blue pixels 4B so as to fill through holes for a large number of pixels of the black mask 3.

Generally, the black mask 3 made of chromium metal is formed by a usual photolithography technique from a chromium vapor deposition film having a thickness of about 1000 Å, and the thickness of the pixels 4R, 4G, 4B sequentially formed for each color is from 1 to 4. It is about 2 μm.

The top coat layer 5 formed so as to cover the pixels 4R, 4G, 4B in order to fill the steps and gaps of the pixels 4R, 4G, 4B and flatten it is transparent and electrically insulating and has a thickness of Is about 1 to 2 μm.

A large number of transparent electrodes 6 formed on the top coat layer 5 and arranged in the thickness direction of the drawing paper, and a large number of transparent electrodes 9 formed on the glass substrate 8 and arranged in the left-right direction of the drawing are The thickness is about 0.2 μm, and the thickness of the alignment film 10 covering the transparent electrodes 6 and 9 is about 0.05 μm.

In FIG. 7A, after depositing a chromium vapor deposition film 14 having a thickness of about 1000Å on the surface of the glass substrate 2,
As shown in FIG. 7B from the vapor deposition film 14, a large number of pixel forming through holes are formed.
A black mask 3 having 15 holes formed is formed.

Next, as shown in FIG. 7C, a photosensitive resin layer 16 containing a first color pigment covering the black mask 3 is applied. The resin layer 16 is generally applied by spin coating so that the thickness after baking is about 1 to 2 μm.

Then, the resin layer 16 is heated at 85 to 100 ° C. for about 2 to 5 minutes to be pre-baked, and then the resin layer 16 is exposed by using a predetermined mask, developed, and post-baked. ), A first pixel, for example, a pixel 4R is formed on the glass substrate 2.

Thereafter, as shown in FIG. 8 (a), a second pixel, for example, a pixel 4G is formed on the glass substrate 2 in the same manner as the pixel 4R, and a third pixel, for example, a pixel 4B is formed as shown in FIG. 8 (b). Form.

Next, as shown in FIG. 8C, a topcoat layer 5 for filling the gaps between the pixels and flattening the unevenness of the pixels 4R, 4G, 4B is formed, and then the topcoat layer 5 is formed as shown in FIG. 8D. A transparent conductive film (ITO film) 17 for forming the transparent electrode 6 is deposited on the coat layer 5.

[0015]

In the conventional color filter as described above, when forming the pattern of the pixels 4R, 4G, 4B, the thickness of the resin film 16 by the spin coating method has an error of about 2% ( When the average thickness is 2 μm, a variation of about 400 Å) occurs, and the viscosity of the resin liquid changes depending on the type and amount of the mixed pigment.
There are problems that it is difficult to make the thicknesses of R, 4G, and 4B uniform, and that the light transmittance is lowered because the topcoat layer 5 needs to be thickened.

Also, the pixels 4R, 4G, 4B are made by polishing.
A method of making the thicknesses of the pixels uniform is proposed, but the pixels 4G, 4B
Pixel 4R is harder to polish than. Therefore, in the conventional color liquid crystal display panel subjected to the polishing process, the thickness of the pixels 4R, 4G, and 4B varies, which causes color unevenness in transmitted light, which impairs the manufacturing yield.

[0017]

In order to solve the above problems, the present invention is applied to a color liquid crystal display panel. According to FIG. 1, the surface of a black mask 23 formed on a transparent substrate 22 is shown. And the surface of a large number of color pixels 4R, 4G, 4B filling the through holes of the black mask 23 on the same plane, and further covering the black mask 23 and the color pixels 4R, 4G, 4B to a thickness of 0.5 μ.
It is a color filter having a structure in which a top coat layer of about m is applied.

As a method of manufacturing such a color filter, a transparent substrate 22 forming a large number of color pixels 4R, 4G, 4B has a thickness required by the pixels 4R, 4G, 4B or a metal film or thicker than necessary. After depositing a black resin film harder than the pixel forming resin, a black mask 23 having a large number of pixel forming through holes is formed by selective etching of the metal film or the resin film, and the pixels 4R, 4G thicker than necessary. After sequentially forming 4B in the through holes, the pixels 4R, 4G, 4B are polished to the same thickness as the black mask 23, or the pixels 4R, 4G, 4B and the black mask 23 are polished to the required thickness.

[0019]

According to the above means, the black mask 23 is made thicker than the conventional one, and the thickness of the black mask 23 is adjusted to the thickness required by the pixels 4R, 4G, 4B, and the surface of the black mask 23 and the pixel 4R are adjusted. , 4G, 4B so that they are flush with the surface, pixels 4R, 4G, 4B with different workability can be polished without steps, and the pixels 4R, 4G, 4B can be polished on top. The topcoat layer to be deposited can be thinned, and the performance of the color filter and the manufacturing yield are improved.

Further, as a method for detecting the thickness of the polished pixels 4R, 4G, 4B in a non-contact manner, a method for detecting the resistance value of the check pattern formed simultaneously with the black mask 23,
We propose a method to detect by the light transmittance of the pixels 4R, 4G, 4B, by which the polishing process can be performed almost in real time.
The productivity of the color filter according to the structure of the present invention is ensured without damaging the relatively soft pixels 4R, 4G, 4B.

[0021]

1 is a sectional view of a color liquid crystal display panel using a color filter according to an embodiment of the present invention, and FIG. 2 is FIG.
3 is an explanatory view (No. 1) of the main manufacturing process of the color filter shown in FIG. 1, and FIG. 3 is an explanatory view (No. 2) of the main manufacturing process of the color filter shown in FIG.

In FIG. 1, in which the same reference numerals are used for the same parts as in the previous figure, the display panel 21 has a large number of pixels 4R, 4G, 4B.
And a glass substrate having the transparent electrode 6 and the like formed on its upper surface (first
The liquid crystal 10 is filled between the glass substrate 22) and the glass substrate 7 having the transparent electrode 8 and the like formed on the lower surface.

Reference numeral 11 is a liquid crystal filling sealant, and 12 is a glass substrate.
A polarizing plate adhered to the lower surface of 22 and a polarizing plate 13 adhered to the upper surface of the glass substrate 8. The color filter on the upper surface of the glass substrate 22 is the same as the pixels 4R, 4G, 4B on the upper surface of the glass substrate 22. Form black mask 23 of thickness, black mask 23
A plurality of red pixels 4R, green pixels 4G, and blue pixels 4B are formed so as to fill the through holes for a large number of pixels.

Generally, the thickness of the pixels 4R, 4G, 4B is 1-2.
A black mask of about μm, which is made of metallic chromium or a harder black resin than the resin for forming the pixels 4R, 4G, 4B.
The thickness t of 23 is the same as that of the pixels 4R, 4G, 4B.

The thickness of the transparent and insulating top coat layer 24 formed on the glass substrate 22 is about 0.5 μm, which is less than 1/2 the thickness of the conventional top coat layer 5 or less. Are pixels 4R, 4G, 4B and black mask 23
Since the upper surface of the above is flat, only the electrical insulating property with respect to the black mask 23 needs to be taken into consideration, so that the thinness can be achieved.

A large number of transparent electrodes 6 are formed on the top coat layer 24 as in the conventional one, and then the transparent electrodes 6 are formed.
An alignment film 9 is applied to cover the transparent substrate 8 and a large number of transparent electrodes 8 having a thickness of about 0.2 μm are formed on the lower surface of the glass substrate 7. Then, an alignment film having a thickness of about 0.05 μm is formed to cover the transparent electrodes 8. The membrane 9 will be deposited.

In FIG. 2A, a chromium film (metal film) 31 having a thickness of, for example, about 2 μm is deposited on the surface of the glass substrate 22, and then a large number of chromium films 31 are formed as shown in FIG. 2B. The black mask 23 having the pixel forming through holes 32 is formed. The black mask 23 is shown in a larger scale in the vertical direction than in the horizontal direction, and the width w of the black mask 23 having a thickness t of 2 μm is generally about 20 to 40 μm.

Next, as shown in FIG. 2C, a photosensitive resin layer 16 containing a first color pigment covering the black mask 23 is applied. The resin layer 16 is generally applied by spin coating so that the thickness after baking becomes thicker than a desired dimension.

Next, the resin layer 16 is heated at 85 to 100 ° C. for about 2 to 5 minutes to be pre-baked, and then the resin layer 16 is exposed using a predetermined mask, developed and post-baked. ), A first pixel, for example, pixel 4R is formed on the glass substrate 22.

After that, as shown in FIG. 2E, the second pixel, for example, the pixel 4G and the third pixel, for example, the pixel 4B are formed on the glass substrate 22 in the same manner as the pixel 4R. Then
As shown in FIG. 3A, after polishing is performed so that the upper surface of the black mask 23 and the upper surfaces of the pixels 4R, 4G, and 4B are flush with each other, the topcoat layer 24 is formed as shown in FIG. Form.

In FIG. 2 (a), the chrome film 31 is changed to a black resin film which is harder than the resin forming the pixels 4R, 4G, 4B, and the black mask 23 is patterned from the resin film to form the pixel 4R. , 4G, 4B may be formed.

The upper surface of the black mask 23 and the pixels 4R, 4G, 4
In the embodiment of the polishing process in which the upper surface of B is the same surface, the thickness of the black mask 23 is set to a predetermined size in advance, and the upper surfaces of the pixels 4R, 4G, 4B are polished so as to match the thickness of the black mask 23. According to the present invention, the first method for forming the black mask 23 and the second method for forming the black mask 23 to have a thickness larger than a predetermined size and polishing the black mask 23 as well as the upper surfaces of the pixels 4R, 4G, 4B to have the predetermined size. Then I will propose.

In the first polishing method using means generally called lapping and polishing, the black mask 23 is harder than the pixels 4R, 4G and 4B, and the pixels 4R, 4G and
Pixels 4G to 4G, 4B due to the difference in processability between 4B
Even if it is easily polished, it becomes difficult to polish the upper surfaces of the pixels 4G and 4B when they are aligned with the upper surface of the black mask 23, and then the upper surfaces of the pixels 4R are aligned with the upper surface of the black mask 23.

Whether the upper surface of the black mask 23 formed of a chromium film or a hard black resin film is aligned with the upper surfaces of the pixels 4R, 4G, 4B by the first polishing method is determined, for example, in an oblique direction to the polishing surface. It can be easily determined by irradiating the illuminating light from the above and visually observing the reflected light.

In the second polishing method using means generally called lapping and polishing, it is necessary to check the thickness of the black mask 23 and the pixels 4R, 4G and 4B.

As a method of checking the thickness, a generally known roughness measuring device may be used, but in the present invention, a structure peculiar to the color filter is used, that is, the black mask 23 is formed of a chrome film. And pixel 4R,
Proposing a method that utilizes the translucency of 4G and 4B,
An example will be described.

FIG. 4 is an explanatory view of the first thickness checking method according to the present invention, which is below (or above) the glass substrate 22.
The glass substrate 22 is irradiated with the emitted light 32 of the light projecting device 31 disposed in the above, and the light sensor 33 disposed above (or below) the glass substrate 22 transmits the transmitted light 34 transmitted through the pixels 4R, 4G, 4B.
Is detected, for example, the spectrum of the transmitted light 34 is measured, and the thickness of the pixels 4R, 4G, 4B is detected by the spectrum.

FIG. 5 is an explanatory view of the second and third thickness checking methods according to the present invention, in which a color filter 41 consisting of a black mask (23) and a large number of pixels (4R, 4G, 4B) is formed. The glass substrate 22 outside the region is provided with a check pattern 42 or 43 formed simultaneously with the black mask by a black film for forming a black mask. Therefore, the check patterns 42 and 43 are polished together with the color filter 41 to have the same thickness as the color filter 41.

In the method of checking the thickness of the color filter 41 in which the check pattern 42 having a U-shape is formed, the probes are brought into contact with both ends of the check pattern 42, and the electrical resistance of the check pattern 42 is measured. Since the electric resistance is determined by the thickness of the check pattern 42, the thickness of the color filter 41 can be known from the electric resistance value.

In the method of checking the thickness of the color filter 41 on which the check pattern 43 is formed, the sheet resistance of the check pattern 43 is measured by using, for example, a four-point probe measuring device. Since such sheet resistance is determined by the thickness of the check pattern 43, the sheet resistance value is used to determine the color filter.
You can know the thickness of 41.

[0041]

As described above, according to the present invention, by adopting a structure in which the surface of the black mask 23 and the surfaces of the pixels 4R, 4G, 4B are in the same plane, pixels having different processability can be obtained.
4R, 4G, 4B can be polished without steps, improving the color tone of the color filter and the manufacturing yield, and
The top coat layer deposited on the pixels 4R, 4G, 4B can be thinned, and the brightness of light transmitted through the color filter is improved.

Further, as a method of detecting the thickness of the polished pixels 4R, 4G, 4B in a non-contact manner, a method of detecting the resistance value of the check pattern formed simultaneously with the black mask 23,
We propose a method to detect by the light transmittance of the pixels 4R, 4G, 4B, by which the polishing process can be performed almost in real time.
This has the effect of ensuring the productivity of the color filter according to the structure of the present invention without damaging the relatively soft pixels 4R, 4G, 4B.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a color liquid crystal display panel using a color filter according to an exemplary embodiment of the present invention.

2A and 2B are explanatory views (No. 1) of main manufacturing steps of the color filter shown in FIG.

FIG. 3 is an explanatory view (No. 2) of the main manufacturing process of the color filter shown in FIG.

FIG. 4 is an explanatory diagram of an embodiment of a first color filter thickness checking method according to the present invention.

FIG. 5 is an explanatory diagram of an embodiment of a second and third color filter thickness checking method according to the present invention.

FIG. 6 is a sectional view showing a main configuration of a conventional color liquid crystal display panel.

FIG. 7 is an explanatory view (No. 1) of main manufacturing steps of the color filter for a liquid crystal display panel shown in FIG. 6.

8 is an explanatory view (No. 2) of the main manufacturing steps of the color filter for liquid crystal display panel shown in FIG.

[Explanation of symbols]

22 is a transparent substrate 23 is a black mask made of a metal film or a black resin film 4R, 4G, 4B is a pixel 31 is a metal film 41 is a color filter 42, 43 is a thickness check pattern made of a metal film

Claims (8)

[Claims] 1. A black mask formed on a transparent substrate (22).
A color filter characterized in that the surface of (23) and the surface of a large number of color pixels (4R, 4G, 4B) filled in the through holes of the black mask (23) are on the same plane. 2. A transparent insulation film having a thickness of about 0.5 μm formed on the surface of the black mask (23) and the surface of a large number of color pixels (4R, 4G, 4B) formed on the same plane. A color filter comprising a transparent top coat layer (24) deposited thereon. 3. A transparent substrate (22) forming a large number of color pixels (4R, 4G, 4B) and a metal film having a thickness required by the pixels (4R, 4G, 4B).
(31) is deposited, a black mask (23) having a large number of pixel forming through holes is formed by selective etching of the metal film (31), and the pixels (4R, 4G, 4B thicker than the required thickness are formed. ) Are sequentially formed for each color in the through holes, and then the pixels (4R, 4G, 4B) are polished to the same thickness as the black mask (23). 4. A transparent substrate (22) forming a large number of color pixels (4R, 4G, 4B) is coated with a metal film (31) thicker than the pixel (4R, 4G, 4B) requires. , A black mask (23) having a large number of pixel forming through holes by selective etching of the metal film (31)
And forming the pixels thicker than the required thickness (4R, 4G, 4B)
After sequentially forming different colors in the through hole, the pixel (4R, 4
A method for manufacturing a color filter, which comprises polishing G, 4B) together with the black mask (23) to the required thickness. 5. A black resin film, which is thicker than the pixel (4R, 4G, 4B) required by the pixels (4R, 4G, 4B) and harder than a pixel forming resin, is applied to a transparent substrate (22) forming a large number of color pixels, and the resin is A black mask (23) having a large number of pixel forming holes is formed by selective etching of the film, and the pixel (4) thicker than the required thickness is formed.
R, 4G, 4B) are sequentially formed in the through hole for each color, and then the pixels (4R, 4G, 4B) are polished together with the black mask (23) to the required thickness. Method for manufacturing color filter. 6. When polishing according to claim 2 or 3,
4. The method of manufacturing a color filter according to claim 2, wherein the color purity or the transmittance of the pixels (4R, 4G, 4B) is measured to obtain the required thickness. 7. The polishing according to claim 2, wherein a thickness check pattern (42, 43) independent of the black mask (23) from the metal film (31) is formed together with the through hole, and the pattern (42). 3. The method for manufacturing a color filter according to claim 2, wherein the electrical resistance of (43, 43) is measured to obtain the required thickness. 8. The black mask according to claim 1 or 2.
(23) and pixels (4R, 4G, 4B) are formed, and then a transparent insulating topcoat layer having a thickness of about 0.5 μm is deposited on them. 3. The method for producing a color filter according to item 3.