JP3191664B2 - Black matrix for display device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a black matrix which is provided around a pixel of a display device and blocks light from behind to improve display visibility, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In order to improve display visibility such as improvement of contrast on a display surface of a display device, a black layer for shielding light may be formed on portions other than pixels on the display surface. Usually, this shielding film is called a black matrix because it is arranged between pixels that form a display surface side by side regularly.

[0003] The black matrix is used in display devices based on various principles, but its material and function are different depending on the manufacturing process and structure depending on the type of display device. For example, a black matrix used for a CRT must be made of a material that can withstand a heat treatment process in order to seal the CRT in a vacuum state. In addition, the conductive material must be such that electrons irradiated from the electron gun do not charge. For this reason, the black matrix for CRT is formed by lift-off using, for example, graphite as a material. On the other hand, for example, the black matrix used in LCDs may be either an organic substance or an inorganic substance as a material, but since the LCD is a display element using a backlight, it represents OD (Optical Density, optical density). Value, expressed as log transmittance- ¹ ). Therefore, the black matrix for LCD is
For example, it is formed by a sputtering method and an etching method using Cr or Cr and CrO _x which is an inorganic material, or by a photolithography method using a resin which is an organic material.

[0004]

SUMMARY OF THE INVENTION A fluorescent display tube (VFD,
Vacuum Fluorescent Display is a display element that performs display by emitting electrons emitted from a cathode to an anode and emitting light from a phosphor provided on the anode inside an envelope in a high vacuum state. There is also a cathode using a field emission cathode (FEC, Field Emission Cathode) as the VFD cathode. The field emission cathode utilizes a phenomenon in which electrons are field-emitted from the tip of the emitter by an electric field formed by a gate provided near the emitter.
VFD using FED (Field Emission Displ.)
ay).

[0005] In the manufacturing process of the VFD or the FED, there are high-temperature processing steps such as a sealing step of an envelope and a firing step of a phosphor layer and the like. Therefore, the black matrix for VFD is
It must be able to withstand a heat treatment process at about 500 ° C. In addition, the selection of the material of the VFD black matrix includes a condition that the electric resistance is high. Examining various materials conventionally used as materials for black matrices from this point of view, graphite is conductive, Cr is conductive and the manufacturing cost is high, and Cr and CrO _x have low electrical resistance. In addition to the low cost, the production cost is high. Since the resin is an organic substance, it is susceptible to heat and has a problem that the OD value is small.

An object of the present invention is to provide a black matrix for a display device suitable for a VFD or FED black matrix and a method of manufacturing the same.

[0007]

According to the first aspect of the present invention, there is provided a method of manufacturing a black matrix for a display device, wherein the particle diameter is in the range of 0.1 to 0.1.
Black pigment particles of 1 μm or less,
Copolymerizing the orchid with an alkoxysilane having a photosensitive group
Si containing polymer having photosensitive group obtained by
A compound and a forming solution containing a high boiling point polar solvent are applied to a glass substrate.
Forming a thin film by coating on the surface; and patterning the thin film.
And firing the glass substrate to form SiO 2
Forming step ₂ .

According to a second aspect of the present invention, there is provided a method of manufacturing a black matrix for a display device according to the first aspect.
In a method for producing a rack matrix, a tetrafunctional alcohol
Silicane consisting of silicane and alkoxysilane having a photosensitive group
A copolymer having a photosensitive group by copolymerizing with a run coupling agent
In the above reaction for obtaining a limer, an alcohol having a photosensitive group
Increase the ratio of the silane coupling agent consisting of xysilane
And adjusting the number of photosensitive groups in the polymer.
It is a sign .

According to a third aspect of the present invention, there is provided a method of manufacturing a black matrix for a display device according to the first aspect .
The compound is characterized by containing a photopolymerization initiator and an auxiliary .

[0010] manufacturing process of the a display device for black matrix according to claim 4, glass in the manufacturing method for a display device for black matrix according to claim 3, wherein the formation fluid
Attempts to form a thin film by applying it on the surface of the substrate
Through a mask with a black matrix pattern
Exposed on the thin film, and the black matrix of the thin film
Parts other than the parts that should be left as
Characterized in that that.

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. This example relates to a fluorescent display device with a color filter having a black matrix. The color filters are three colors of red (R), green (G), and blue (B), and are arranged on the display surface according to a certain rule. The black matrix defines each adjacent color filter. First, the raw material of the forming liquid used for manufacturing the black matrix will be described. The forming liquid is formed by mixing and dispersing the following raw materials. This forming liquid contains a photosensitive substance in its components, and after being applied onto a glass substrate, can be processed into an arbitrary matrix shape by a patterning and developing operation using a mask and a light irradiation device.

(1) Pigment The pigment of this example is a composite oxide of Cu—Fe—Mn or Cu
-It is a black pigment particle composed of a composite oxide of Cr-Mn. The average particle size is 0.1 μm or less, preferably the average particle size is about 0.06 μm. The specific surface area is 30 m ² / g
It is.

(2) Photosensitive organic Si compound as organic Si compound In this example, the black mask is formed on a glass substrate. Since Si in the photosensitive organic Si compound adapts to glass, SiO ₂ is suitable as a fixing agent for glass. As shown in the following chemical formula (1), when a tetrafunctional alkoxysilane is copolymerized with a silane coupling agent composed of an alkoxysilane having a photosensitive group, a polymer having a photosensitive group is generated. The photosensitive organic Si compound is composed of this polymer. Or, it contains at least this polymer.

[0020]

Embedded image

In the above formula, R is an alkyl group and X is a photosensitive group. The ratio between the tetrafunctional alkoxysilane and the alkoxysilane having a photosensitive group is arbitrarily set in the range of 50:50 to 0: 100. As the silane coupling agent having a photosensitive group, a silane coupling agent having a photosensitive group such as an acryloyl group or a vinyl group can be used. For example, vinyltrimethoxysilane represented by the chemical formula (2), γ-methacryloxypropyltrimethoxysilane represented by the chemical formula (3), γ-methacryloxypropyltriethoxysilane represented by the chemical formula (4) can be used.

[0022]

Embedded image

[0023]

Embedded image

[0024]

Embedded image

(3) Solvent 1) A propylene glycol ether-based high-boiling polar solvent is used to make the photosensitive organic Si compound liquid to be applied to a glass substrate. Since it has a high boiling point, it is difficult to dry, which is advantageous for thin coating. Since it is a polar solvent, the dispersibility of other components is good. Examples of such a solvent include the following. The number in parentheses is the boiling point of each solvent (℃)
Is shown. Dipropylene glycol methyl ether (18
8), tripropylene glycol methyl ether (24
2), ethylene glycol methyl ether (125),
Ethylene glycol ethyl ether (136), ethylene glycol butyl ether (171), diethylene glycol methyl ether (194), diethylene glycol ethyl ether (202), diethylene glycol butyl ether (230).

2) If necessary, a photocurable resin, specifically, a monomer such as PEG or HEMA is added. In this example, since a photosensitive organic Si compound is used as the organic Si compound, a photocurable resin as a solvent is not necessarily required, but if added, the sensitivity to ultraviolet rays is further improved.

(4) Photopolymerization initiator In order to start a curing reaction by exposure, DETX (diet
hylthioxanthone) and BP100
Or a benzophenone-based photopolymerization initiator. The structural formula of DETX is shown in chemical formula (5).

[0028]

Embedded image

(5) Auxiliary As an auxiliary for the initiator, triethanolamine (TE)
Amine-based auxiliaries such as A) may be added.

A forming liquid is prepared by using each of the above-described raw materials. First, 20% of a pigment, 10% of a photosensitive organic Si compound and 70% of a solvent are mixed by weight%. The mixed raw materials are dispersed until the pigment is loosened into the primary particles. The dispersion is performed using a ball mill, a sand grinder (Nanomizer) or the like. When the pigment is loosened to the primary particles, the hiding power increases and the light-shielding property increases. The solvent may be replaced with a photocurable resin, or a part of the solvent may be substituted with a photocurable resin, and an appropriate amount of a photopolymerization initiator and an auxiliary may be added.

The above forming liquid is applied to the surface of a glass substrate using a spinner. Spinner 1000-3000
It has a disk that rotates at rpm. A glass substrate is fixed on the disk, and the disk is rotated at a predetermined rotation speed. When an appropriate amount of the forming liquid is dropped on a rotating glass substrate, the forming liquid spreads outward due to centrifugal force and becomes thinner to form a film. A thin film having an appropriate thickness is formed on a glass substrate by adjusting the amount of liquid dropped, the number of rotations, the processing time, and the like.

The glass substrate is pre-baked at 120 to 150 ° C. Next, a mask having a pattern corresponding to the shape of the black matrix formed with the forming liquid is prepared and placed on the glass substrate. The glass substrate is exposed through the mask. By developing, the thin film is formed in a predetermined pattern. Next, this glass substrate is heated to 140 to 150 ° C.
And post bake.

Next, the glass substrate is fired. Organic substances in the thin film are decomposed in an oxidizing atmosphere, and the inorganic component Si becomes SiO ₂ to fix the black pigment particles, thereby completing the black matrix.

Table 1 is a table showing a comparison between the optical characteristics of the black matrix of this embodiment and the conventional black matrix.

[0035]

[Table 1]

One of the most important characteristics of the black matrix is the optical characteristics. The lower the transmittance and the reflectance, the better the visibility of the display. The reflectance of the two black matrices of this example is equivalent to that of Cr / CrO _x , and the OD value is 1.1 μm, which is much higher than that of the resin film.
When used in VFD, there is no problem if the OD value is 2 or more because it is not a backlight system like LCD. As can be seen from the above data, it can be said that the black matrix of this example has excellent optical characteristics.

The black matrix of this example is mounted on a VFD
We experimented to see how the contrast was improved.
The following table shows the results. By firing on a glass substrate
The thin film of the forming solution formed by
HF) and black mask with a line width of 60 μm
A tricks pattern is formed on the display surface. Black mato
A light emitting display of VFD is configured on the RIX with a known structure
I do. Halo the display surface from a direction 30 ° from the perpendicular of the display surface
Irradiation with a gen lamp, brightness of display surface (cd / m ^Two) Shine
It was measured with a degree meter. Illumination on display surface by halogen lamp
While changing (lx) to 100, 200, 500
Display surface brightness when VFD is ON and OFF
(Cd / m^Two) Was measured with a luminance meter. Where VFD is
When ON, the luminance [ON] is the VFD light emission luminance + display
This shows the surface reflection luminance. Brightness when VFD is OFF [OF
F] indicates the display surface reflection luminance. Perform the above measurement
With and without matrix
I went. The contrast CR is expressed as CR = [ON] / [O
FF].

[0038]

[Table 2]

As described above, it can be seen that the contrast is always higher when there is a black matrix than when there is no black matrix, regardless of changes in external light. That is, it was confirmed that the contrast on the display surface of the VFD was improved by mounting the black matrix of this example.

According to this example, in the forming solution, the photosensitive organic Si compound has a function of assisting the dispersion of the pigment and maintaining the dispersed state after the dispersion.

The photosensitive organic Si compound is converted into Si by firing.
Since it is O ₂ , the obtained black matrix has a remarkably high fixing strength, which is 9H or more in a pencil strength test. FIG.
As shown in (a), since the pigment 1 is fixed in SiO ₂ while maintaining a good dispersion state, the pigment 1 has good optical characteristics.
The surface of the black matrix is flat and has good gloss like a glass sheet. On the other hand, in the conventional black matrix, as shown in FIG. 1B, the pigment 1 is aggregated in the black matrix and the surface is uneven, so that the incident light is scattered. For example, assuming that the glossiness of the reference plate glass is 100, the glossiness of the black matrix of this example is 100, and the glossiness of the conventional black matrix is 10 or less. Therefore, when another film is laminated on the black matrix of the present example, it can be formed under the same favorable conditions as when forming a film on a plate glass.

In this embodiment, when the photosensitive organic Si compound is baked to form SiO ₂ , the stress generated inside the thin film is reduced by the photosensitive group and the alkyl group of the photosensitive organic Si compound. That is, since the photosensitive group and the alkyl group are hardly oxidized and do not burn at a stretch, the film is fired without cracks and vitrification proceeds gradually. For this reason, the black matrix of this example can be made thicker,
In the case of a film thickness of about 25 μm, there is no breakage during manufacturing.

In the present embodiment, an inorganic material such as a pigment and OH
High affinity for groups and high affinity for organic solvents and alkyl groups. By this coupling effect, the pigment can be dispersed in the liquid phase and the dispersed state can be maintained. Further, by selecting the kind of the alkyl group of the photosensitive organic Si compound, the compatibility between the solvent and the pigment can be improved.

As a method for producing a photosensitive organic Si compound as an organic Si compound, a reaction represented by chemical formula (6) can be used in addition to the reaction represented by chemical formula (1).
In this reaction, the ratio of both substances in the reaction of the chemical formula (1) for copolymerizing a tetrafunctional alkoxysilane and a silane coupling agent comprising an alkoxysilane having a photosensitive group is set to 0: 100. That is, a polymer having a photosensitive group is produced by copolymerizing a silane coupling agent composed of an alkoxysilane having a photosensitive group.

[0045]

Embedded image

In the reaction of copolymerizing a tetrafunctional alkoxysilane and a silane coupling agent comprising an alkoxysilane having a photosensitive group, by changing the ratio of both substances, the photosensitive group of the photosensitive organic Si compound obtained can be changed. The number can be adjusted. By adjusting the number of photosensitive groups, the above-described effect of preventing the black matrix from cracking changes. In the case of producing a black matrix having a somewhat large thickness, the ratio of the silane coupling agent composed of an alkoxysilane having a photosensitive group may be increased to produce a photosensitive organic Si compound.

Next, with reference to FIG. 2, a description will be given of a fluorescent display device which is a display device with a filter having a black matrix of this embodiment. A black matrix 3 is formed on an anode substrate 2 which is a glass substrate. First, a liquid for forming a black matrix is applied to the surface of the anode substrate 2 to form a thin film. A mask having a predetermined pattern is prepared, and is arranged above the anode substrate 2. The thin film is exposed to light through this mask, and portions other than the portion of the thin film to be left as a black matrix are removed by development. After the development, post baking is performed. Next, R (red), G (green), and B (blue) color filters are formed on the black matrix. The filters of each color are formed for each color by the photolithography method described above, and post-baked. After the three color filters are post-baked, the entire anode substrate is fired. As described above, since the surface of the black matrix has good gloss, the color filter formed thereon can be formed with the same high quality as that formed directly on the glass substrate.

Next, each of the filters R, G, B of the anode substrate 2
A transparent anode conductor 4 such as an ITO film is formed thereon.
A phosphor layer 5 is provided on each anode conductor 4 to form an anode 6. Although not shown, a control electrode is arranged above the anode 6 of the anode substrate 2. Further, a filament-shaped cathode serving as an electron source is provided above the control electrode. A box-shaped container is sealed on the upper surface side of the anode substrate 2 to form a box-shaped envelope in which the various electrodes and the like are housed. The inside of the envelope is evacuated and maintained in a high vacuum state.

The fluorescent display tube is driven. The electrons emitted from the cathode are accelerated and controlled by the control electrode.
Shoot at. Light emitted from the phosphor layer 5 of the anode 6 is observed from outside the anode substrate 2 through the light-transmitting anode conductor 4, the color filters R, G, B, and the light-transmitting anode substrate 2.
The phosphor layer 5 used in this example is Zn that emits blue-green light.
O: Zn phosphor, but depending on each color filter, R
(Red), G (green), and B (blue) can be displayed. Since the display portion of each color is bordered by the black matrix, the display contrast is good.

The above description is for the case of VFD. FED
In the case of, the configuration is as follows. A cathode substrate is arranged at a predetermined interval on the anode substrate, the periphery of both substrates is sealed with a sealing agent also serving as a spacer, and the inside of both substrates is exhausted. The cathode substrate has a cathode conductor formed on the inner surface of the cathode substrate, an insulating layer laminated on the cathode conductor, a gate electrode laminated on the insulating layer, and a large number of layers formed on the insulating layer and the gate electrode. A hole and a cone-shaped emitter disposed on the cathode conductor inside the hole are provided. In the case of the FED, electrons are emitted from the tip of the emitter by the electric field formed by the gate electrode, and the electrons strike the phosphor layer of the anode to emit light.

[0051]

[0052]

[0053]

[0054]

[0055]

In the above description, a fluorescent display tube or a field emission type fluorescent display tube has been described as a display device to which the black matrix of this embodiment is applied. Can be applied.

[0057]

According to the present invention, a forming liquid containing black pigment particles, an organic Si compound and a solvent is applied to the surface of a glass substrate to form a thin film, which is patterned and fired to form a black matrix. The following effects can be obtained.

1) A black matrix having good optical characteristics and visibility for VFD and FED can be obtained.
When applied to the ED, the display contrast on the display surface is improved.

2) The organic Si compound is converted into SiO
₂ , which is a structure in which black pigment particles are dispersed therein, and has high strength as a film. Further, the hiding power of the black pigment particles is maximized, and a high O
D value and low reflectivity could be realized.

3) When the organic Si compound has a photosensitive group, patterning can be performed directly by photolithography without using a resist.

4) When the organic Si compound has a photosensitive group, the photosensitive group relaxes the stress in the film when the organic Si compound is baked to form SiO ₂ , so that the crack is formed at a film thickness of about 25 μm. It is possible to control the film thickness without occurrence.

5) When the organic Si compound has an alkyl group, when the organic Si compound is baked to form SiO ₂ , the alkyl group relaxes the stress in the film.
The thickness can be controlled without causing cracks at the following thicknesses.

6) After firing, the surface of the black matrix of the present invention becomes like a glass film, and the surface has the same glossiness as plate glass. When another functional film (for example, various filters or conductive films, etc.) is formed on the black matrix in a later step, the same thickness and quality as when the functional film is formed on a glass plate are used. A film can be formed.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a black matrix according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of a conventional black matrix.

FIG. 2 is a cross-sectional view of a fluorescent display device including a black matrix according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pigment 2 Anode substrate 3 Black matrix 4 Anode conductor 5 Phosphor layer 6 Anode R, G, B Color filter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-115743 (JP, A) JP-A-5-307940 (JP, A) JP-A-4-87143 (JP, A) JP-A-9-99 54431 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 9/227 H01J 29/32 H01J 31/12 H01J 31/15

Claims (4)

(57) [Claims] 1. An organic Si containing a photosensitive group-containing polymer obtained by copolymerizing black pigment particles having a particle size of 0.1 μm or less with a tetrafunctional alkoxysilane and a photosensitive group-containing alkoxysilane. A step of forming a thin film by applying a compound and a forming solution containing a high-boiling-point polar solvent to the surface of a glass substrate, patterning the thin film, and firing the glass substrate to form SiO _2. Of manufacturing a black matrix for a display device. 2. The reaction of obtaining a polymer having a photosensitive group by copolymerizing a tetrafunctional alkoxysilane and a silane coupling agent comprising an alkoxysilane having a photosensitive group, the silane coupling comprising an alkoxysilane having a photosensitive group. 2. The method according to claim 1, wherein the number of photosensitive groups in the polymer is adjusted by increasing the ratio of the agent. 3. The method for producing a black matrix for a display device according to claim 1, wherein the organic Si compound contains a photopolymerization initiator and an auxiliary. 4. A thin film is formed by applying a forming liquid on a surface of a glass substrate, and the thin film is exposed through a mask having a pattern of a black matrix to be formed, and is left as a black matrix of the thin film. 4. The method according to claim 3, wherein a portion other than the portion is removed by development.