JPH11119207A - Color filter substrate and liquid crystal device using the substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the difference in level on the surface of a flattened layer surface, in a color filter substrate constituting a liquid crystal device of a color display. SOLUTION: A light shielding film 21, which has dotty apertures 23 in a display region 6 and covers peripheral regions 7 over the entire surface is formed on a transparent substrate. Respective color filters are formed in such a manner that the covering area rate [e×f×100/(g×h)] of the color filters 24 of the peripheral region 7 to the substrate attains 70 to 95% with respect to the covering area rate [a×b×100/(c×d)] of the color filters 22 of the display region to the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color liquid crystal element used for a display device and the like, and a color filter substrate as a constituent member thereof.

[0002]

2. Description of the Related Art In recent years, with the development of personal computers and the like, the demand for liquid crystal elements used as display devices is increasing. In particular, there is a demand for higher image quality of color display.

FIG. 1 is a schematic plan view of a general liquid crystal element. In the figure, reference numerals 1 and 3 denote transparent substrates made of glass or the like, each having a transparent electrode (not shown) provided inside. Reference numerals 2 and 4 denote mounting terminal portions for connecting driving circuits for the transparent electrodes formed on the transparent substrates 1 and 3, respectively. The transparent substrates 1 and 3 are adhered by a sealing material 5 to sandwich the liquid crystal. The area 6 where the transparent electrodes formed on the transparent substrates 1 and 3 face each other is an area for driving the liquid crystal, and is called a display area. The area 7 surrounding the display area is a peripheral area.

FIG. 8 schematically shows a cross-sectional view of an example of a conventional liquid crystal element. In the figure, 21 is a metal light shielding film, 22 is a dot color filter formed in a display area, 24 is a dot color filter formed in a peripheral area, 31 is a flattening layer, 81 and 83 are transparent electrodes, 82 and 84 are alignment control films, 86 is a spacer, and 87 is a liquid crystal. FIG.
Is an example of an element having a simple matrix structure.
And 83 are formed in stripes orthogonal to each other. Further, the transparent substrate 3 is arranged on the viewer side.

The metal light-shielding film 21 is made of a metal such as molybdenum and has a thickness of at least 0.08 μm or more, usually 0.1 to 0.2 μm, so that the transmittance is close to 0%. . FIG. 9 is a schematic plan view of a color filter group. As shown in FIG. 9, the metal light-shielding film 21 has a dot-shaped opening 23 in the display area 6 so as to shield light between adjacent color filters. On the other hand, the display area 7 is formed over the entire surface in a solid shape.

In the display area 6, the color filters are arranged in a dot-like manner on the opening 23 of the metal light-shielding film 21 with red (R), green (G), and blue (B) as one pixel. In consideration of the spectral transmittance, it is formed in a thickness of 0.8 or more, usually in the range of 1.0 to 1.8 μm, and the peripheral region 7 is also provided with any one of R, G, and B colors or display. Area 6
In the same manner as described above, dots are formed in three colors. Note that, for example, each dot of the color filter 24 in the peripheral area 7 is formed larger than each dot of the color filter in the display area 6. Further, the color filter 24 in the peripheral region 7 may be formed in a solid shape on the metal light shielding film 21 in some cases.

The reason why the color filter 24 is formed in the peripheral area 7 is to prevent a sharp step from being generated at the boundary between the display area 6 and the peripheral area 7. The size of the formed color filter is changed in consideration of the adhesion, and the color filter 22 in the display area 6 is strong when formed on the transparent substrate 1 (often a glass substrate). This is because the adhesiveness is obtained, but in the case of the color filter 24 formed on the metal light-shielding film 21, the adhesiveness is slightly weakened and the color filter 24 may be peeled off during the manufacturing process.

The color filter 24 in the peripheral area 7
Is often formed in one color of blue (B), which also has better adhesion than other colors,
This is because when there is a pinhole or the like, the effect of reducing light leakage is higher than that of other colors.

Usually, on the color filter group, protection of the color filters, flattening between the color filters, and electrical insulation between the electrode group formed on the upper layer and the metal light shielding film 21 are usually performed. A flattening layer 31 made of a transparent resin is formed.

As a liquid crystal element, as shown in FIG. 8, a transparent substrate 1 on which a color filter is formed is arranged to face a transparent substrate 3. On the opposing surfaces of the respective substrates, a transparent electrode 81 is formed on at least the display area 6 on the planarizing layer 31 on the transparent substrate 1 and a transparent electrode 84 is also formed on the transparent substrate 3.
In both substrates, alignment control films 82 and 83 each made of a thin film of polyimide or the like for aligning liquid crystal molecules are laminated on the transparent electrode with the same thickness of 0.02 to 0.05 μm. The two substrates are opposed to each other by the seal member 5 under pressure via the spacer 86 and are bonded together, and the liquid crystal 87 is sealed in the gap. After the sealed liquid crystal 87 is bonded to the upper and lower substrates, the inside of the cell is depressurized, and is injected from a liquid crystal injection port (8 in FIG. 1) by a vacuum injection method using a pressure difference between the inside and the outside of the cell. It is sealed by 1) 9).

[0011]

However, in the conventional liquid crystal device, there has been a problem that the flattening layer 31 cannot be sufficiently flattened. FIGS. 10 and 11 schematically show cross sections of a color filter substrate (structure in which a flattening layer 31 is formed on a transparent substrate 1) used in a conventional liquid crystal element. As shown in these figures, since the display area 6 and the peripheral area 7 have different color filter covering areas, the flattening layer forming material applied on the color filters when forming the flattening layer 31 is formed. The amount flowing between the color filter dots changes. Accordingly, the thickness of the flattening layer 31 on the color filters 22 and 24 becomes different. Therefore, a step is generated between the display area 6 and the peripheral area 7, and the shape becomes a continuous slope at the boundary. Even if the color filter 24 formed in the peripheral area has the same size and shape as the display area 6, at least the metal light shielding film 21
The film thickness has a step. This problem is remarkable in a color filter substrate used for a liquid crystal element having a small pixel and performing high-definition display.

The problem with the color filter substrate is that
This also affects the liquid crystal element formed using the color filter substrate, and the cell gap locally changes near the peripheral region 7. In particular, in a ferroelectric liquid crystal element having a thin cell gap of 1 to 2 μm, the influence becomes strong.
If the difference in the cell gap locally exceeds 0.05 μm, color unevenness is generated and the drive margin is reduced, resulting in display unevenness and deterioration of display quality.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to realize a color filter substrate in which local steps are prevented, and to provide a liquid crystal element with high display quality without display unevenness.

[0014]

SUMMARY OF THE INVENTION The present invention is a color filter substrate used for a liquid crystal device having a display area and a peripheral area surrounding the display area, and has at least a dot-shaped opening in the display area on a transparent substrate. A light-shielding film that covers the entire surface of the peripheral region; a dot-shaped color filter group made of a colored resin provided on the opening of the light-shielding film in the display region and on the light-shielding film in the peripheral region; The color filter group includes a flattening layer coated on the entire surface, and in the color filter group, the coverage area ratio of the color filter provided in the peripheral region to the substrate is 70 to 70% of the coverage area ratio of the color filter provided in the display region to the substrate An object of the present invention is to provide a color filter substrate characterized by being 95%.

Further, the present invention provides a liquid crystal element in which liquid crystal is sandwiched between a pair of electrode substrates, wherein one of the substrates is formed using the color filter substrate. Things.

In the present invention, the flattening layer is formed by forming the color filter provided in the peripheral region so that the coverage ratio of the color filter provided in the display region to the substrate is 70 to 95%. In this case, the flow volume of the material for forming the flattening layer flowing between the color filters is controlled, and the thickness of the flattening layer on the color filter in the display area and the thickness of the flattening layer on the color filter in the peripheral area are changed. In addition, the step on the surface of the flattening layer in the display region and the peripheral region can be suppressed to a level that does not substantially affect the surface.

[0017]

FIG. 2 is a schematic plan view of an embodiment of the color filter substrate of the present invention, and FIG. 3 is a schematic sectional view thereof. In the figure, a and b are the color filters 2 in the display area 6.
2 is the size of one dot, and c and d are the pitches of the color filters 22 in the display area 6. Similarly, e, f
Is the size of one dot of the color filter 24 in the peripheral area 7, and g and h are pitches. One dot of the color filter 22 in the display area 6 functions so as to transmit light at the opening 23 defined by the light shielding film 21 made of a black metal material or the like.

In the present invention, the coverage area of one dot of the color filter is represented by a × b and e × f, and the coverage area ratio (%) of the color filter to the substrate is a × b. × 100 / (c × d) and e × f × 100 / (g × h).

In the present invention, the covering area ratio of the color filter 24 provided in the peripheral region 7 to the substrate is set to 70 to 95% of the covering area ratio of the color filter 22 provided in the display region 6 to the substrate. . Further, it is preferable to form the color filter 24 provided in the peripheral region 7 so that the area covered by one dot of the color filter 22 provided in the display region 6 is 400% or less.

In the embodiment shown in FIG. 2, each of the color filters 22 and 24 is formed in a square, but may be a rectangle as shown in FIG.
In addition, as long as the relationship between the display area and the peripheral area according to the present invention in the color filter covering area ratio is satisfied, a shape other than a rectangle may be used.

The liquid crystal element of the present invention can be constituted by the same members and manufacturing method as the conventional liquid crystal element except that the above-mentioned color filter substrate is used. That is, as shown in FIG. 8, a transparent electrode and an orientation control film are provided on the flattening layer of the color filter substrate of the present invention. Similarly, an opposing substrate provided with the transparent electrode and the orientation control film and a sealing material are provided. And formed by injecting liquid crystal.

[0022]

【Example】

Example 1 As a first example of the present invention, a color filter substrate having the structure shown in FIGS. 2 and 3 was manufactured. First, a metal light-shielding film 21 made of molybdenum was formed to a thickness of 0.1 μm on a glass substrate 1 having a thickness of 1.1 mm. As a forming method, after forming the entire surface by sputtering, it was patterned into a desired shape by photolithographic etching.
The size of the opening 23 of the metal light shielding film 21 in the area corresponding to the display area 6 was 44 μm × 44 μm, and the interval between the openings was 16 μm.

On the metal light-shielding film 21, R, G, and B colored resins ("PA-101" manufactured by Ube Industries, Ltd.)
2 "series) color filter 22 (a = b =
(50 μm, c = d = 60 μm, covering area ratio = 69%)
Were sequentially formed to a thickness of 1.5 μm. As a formation method, after one-colored resin was applied over the entire surface by a spinner, temporary drying, exposure, development, and post-baking were performed using a hot plate, and this process was repeated for R, G, and B to sequentially pattern. In the peripheral region 7, a dot-shaped color filter 24 (e =
f = 95 μm, g = h = 120 μm, covering area ratio = 63
%, 90% with respect to the covering area ratio of the color filter 22,
(361% of the area of the color filter 22) was formed simultaneously with the step B of the color filter 22 so as not to be peeled off in a later step.

Further, a flattening layer 31 made of a transparent resin ("PSB-K31" manufactured by Toray Industries, Ltd.) is formed on the color filters 22 and 24 to a thickness of 1.0 to 2.0 μm by spinner coating and baking. The entire surface was laminated so as to be as follows. As a result, due to the flow leveling in the gap between the color filters 22 and 24 made of the transparent resin material, the peripheral area 7 and the display area 6
In this case, the film thickness of the planarizing layer 31 is different, and as a result, the maximum step A between the peripheral region 7 and the display region 6 shown in FIG.
m.

[Comparative Example 1] The color filter 24 shown in FIG. 2 was changed to e = f = 108 μm (coverage area ratio = 80%, 116% with respect to the color filter 22 coverage area, A color filter substrate was manufactured in the same manner as in Example 1 except that the color filter substrate was formed at 467%.

As a result, as shown in FIG.
The maximum step A between the display area 6 and the display area 6 was 0.4 μm, and the shape was a continuous slope near the boundary between the display area 6 and the peripheral area 7.

[Embodiment 2] As a second embodiment of the present invention,
A color filter substrate having the structure shown in FIGS. 5 and 6 was manufactured. First, on the same glass substrate 1 as in Example 1, chromium oxide and chromium were laminated to form a metal light-shielding film 21 having a thickness of 0.2 μm to reduce the surface reflectance when a liquid crystal element was formed. The forming method is the same as in the first embodiment. The opening 23 of the metal light shielding film 21 in a region corresponding to the display region 6
Was 80 μm × 280 μm, and the distance between the openings was 20 μm both vertically and horizontally.

A color filter 22 (a = 90 μm, b = 2) is formed on the metal light shielding film 21 in the same manner as in the first embodiment.
90 μm, c = 100 μm, d = 300 μm, covering area ratio = 87%), and the color filter 24 (e = 78 μm)
m, f = 270 μm, g = 100 μm, h = 300 μ
m, covering area ratio = 70%, covering area ratio of the color filter 22 was 80%, and covering area of the color filter 22 was 81%), and the flattening layer 31 was laminated.

Also in the color filter substrate of this embodiment, the maximum step A between the peripheral area 7 and the display area 6 shown in FIG. 6 was within 0.05 μm.

[Comparative Example 2] The display area 6 is also provided in the peripheral area 7.
With the same size and pitch as the color filter (coverage area ratio 87%, 1
00%, 100% of the area of the color filter 22)
A color filter substrate was manufactured in the same manner as in Example 2 except that was formed.

As shown in FIG. 7, the maximum step A between the peripheral area 7 and the display area 6 was 0.2 μm, and the boundary portion had a continuous slope shape.

[0032]

As described above, according to the present invention,
The step between the peripheral area and the display area can be reduced to 0.05 μm or less, and the effect of the step on the display can be substantially prevented. Thus, a liquid crystal element with good display quality can be provided without reducing the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a schematic plan view illustrating a configuration of an example of a liquid crystal element.

FIG. 2 is a schematic plan view illustrating a shape of a color filter of the color filter substrate according to the first embodiment of the present invention.

FIG. 3 is a schematic view showing a cross section of the color filter substrate shown in FIG.

FIG. 4 is a schematic view showing a cross section of a color filter substrate according to a first comparative example of the present invention.

FIG. 5 is a schematic plan view showing a shape of a color filter of a color filter substrate according to a second embodiment of the present invention.

FIG. 6 is a schematic view showing a cross section of the color filter substrate shown in FIG.

FIG. 7 is a schematic diagram illustrating a cross section of a color filter substrate according to a second comparative example of the present invention.

FIG. 8 is a schematic view showing a cross section of a conventional liquid crystal element.

FIG. 9 is a schematic plan view showing the shape of a color filter of a conventional color filter substrate.

FIG. 10 is a schematic view showing a cross section of a conventional color filter substrate.

FIG. 11 is a schematic view showing a cross section of a conventional color filter substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 3 Transparent substrate 2, 4 Mounting terminal part 5 Sealing material 6 Display area 7 Peripheral area 8 Liquid crystal injection port 9 Sealing material 21 Metal light shielding film 22 Color filter (display area) 23 Metal light shielding film opening 24 Color filter (periphery) Region) 31 Flattening layer 81, 83 Transparent electrode 82, 84 Alignment control film 86 Spacer 87 Liquid crystal

Claims (5)

[Claims] 1. A color filter substrate for use in a liquid crystal element having a display area and a peripheral area surrounding the display area, wherein at least a transparent substrate has a dot-shaped opening in the display area and covers the entire peripheral area. Film, a dot-shaped color filter group made of a colored resin provided on the opening of the light-shielding film in the display region and on the light-shielding film in the peripheral region, and a flattening layer entirely coated on the color filter group In the above color filter group, the coverage area ratio of the color filter provided in the peripheral region to the substrate is 7% of the coverage area ratio of the color filter provided in the display region to the substrate.
A color filter substrate, which is 0 to 95%. 2. The color filter substrate according to claim 1, wherein a coverage area of one dot of the color filter provided in the peripheral area is 400% or less of a coverage area of one dot of the color filter provided in the display area. . 3. The light shielding film is made of a metal material.
The color filter substrate as described in the above. 4. A liquid crystal element having a liquid crystal sandwiched between a pair of electrode substrates, wherein one of the substrates is formed using the color filter substrate according to claim 1. A liquid crystal device characterized by the above-mentioned. 5. The liquid crystal device according to claim 4, wherein a substrate opposite to the color filter substrate is arranged on a viewer side.