JP2000260336A - Substrate for display and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate for a display with high contrast, low resistance, and having an electrode free from defect caused by the electrode when forming a dielectric layer on the electrode. SOLUTION: This substrate for a display has an electrode formed on the substrate. The electrod comprises at least two layers, and its lowest layer has a stimulus value Y of 4 to 15 in a XYZ color system, and the average height (hc) of the central part of the cross section of the electrode in the width direction and the maximum height (he) of the sectional end satisfy the relation expressed by an inequality, 1<=he/hc<=2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a display substrate having electrodes and a method for manufacturing the same. The display substrate of the present invention can be used for an image display device using a plasma display panel, a plasma addressed liquid crystal, an electron-emitting device or a fluorescent display device.

[0002]

2. Description of the Related Art As an image display device replacing a large and heavy cathode ray tube, a light and thin so-called flat display has attracted attention. Liquid crystal displays (LCDs) have been actively developed as flat displays, but they still have problems such as dark images and narrow viewing angles. As an alternative to this liquid crystal display, a plasma display panel, which is a self-luminous discharge display, or an image display device using an electron-emitting device, can obtain a brighter image than a liquid crystal display, and has a wider viewing angle. The need for higher resolution and higher screen resolution is increasing.

[0003] Plasma display panels (PDPs)
) Generates a plasma discharge between the opposed anode and cathode electrodes in a discharge space partitioned by partitions provided between the front glass substrate and the back glass substrate, and is sealed in this space. The display is performed by applying ultraviolet rays generated from the gas to the phosphor applied in the discharge space. In this case, the anode electrode and the cathode electrode on the glass substrate have a plurality of linear electrodes arranged in parallel, and the electrodes face each other with a small gap therebetween, and the respective linear electrodes intersect. It is configured to be superimposed so as to face the direction.

A plasma addressed liquid crystal (PALC) display is a TFT-LCD in which a TFT (thin film transistor) array portion is replaced with a plasma channel, and has basically the same structure as the TFT-LCD except for the plasma portion. For the plasma generation part, PD
The technique in P is applicable.

An image display device using an electron-emitting device uses an electron-emitting device as a source of an electron beam, accelerates the generated electron beam to irradiate a phosphor, causes the phosphor to emit light, and displays an image. And has advantages such as being flat and bright and easy to see.

The electron-emitting device includes a thermionic electron-emitting device and a cold cathode electron-emitting device. Cold cathode electron-emitting devices include a field emission type (FE type), a metal / insulating layer / metal type (MIM type), and a surface conduction type. An image forming apparatus using such a cold cathode electron source displays an image by irradiating a phosphor with an electron beam emitted from each type of electron-emitting device to generate fluorescent light. In this apparatus, a front glass substrate (also referred to as a face plate) and a rear glass substrate (also referred to as an element substrate) are used by imparting respective functions. A matrix wiring for connecting the electrodes is provided. Since these wirings intersect at the electrode portion of the electron-emitting device, an insulating layer (dielectric layer) for insulation is provided. Further, a spacer (also referred to as a barrier or a partition) is formed between the two substrates as an anti-atmospheric pressure support member.

[0007] The structure and electrical operation mechanism of a fluorescent display tube (VFD) are similar to a CRT. However, unlike a CRT, a VFD excites a phosphor with a low-speed electron flow of several tens mA at a voltage of several tens of volts. Also in a display using such a VFD element, grid-like, dot-like, or stripe-like anode electrodes are formed.

[0008] Among these electrodes, a technique for blackening the electrodes formed on the front glass substrate is required to improve the contrast of the display screen. For example, JP-A-61-176035 and JP-A-4-272634 propose a method of forming a pattern on a glass substrate by a screen printing method using a blackened silver paste. However, the blackening of the silver paste requires iron, chromium,
A method of mixing a metal oxide such as nickel and ruthenium with silver in an equal amount or more is used. For this reason, the resistance value of the electrode becomes considerably high, and it is necessary to increase the thickness of the electrode, which causes problems such as deterioration of the flatness of the dielectric layer formed on the electrode.

Japanese Patent Application Laid-Open No. 10-40821 describes a photosensitive black conductive paste and a method for forming an electrode having a two-layer structure using the photosensitive conductive paste.

On the other hand, the electrodes are liable to cause defects such as disconnection, short circuit, foreign matter, and edge curl. If these electrodes have a large defect, when a dielectric layer is formed on the electrodes, the smoothness of the dielectric layer is impaired, which causes cracks in the firing step.

In order to achieve a production margin in the mass production of displays and in-plane uniformity on a large substrate, it is necessary to eliminate such electrode defects. There is no known solution to this problem.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a display substrate having an electrode having a high contrast, a low resistance, and having no electrode-related defects when forming a dielectric layer formed on the electrode. Is to provide.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a display substrate having electrodes formed on a substrate, wherein the electrodes are composed of at least two layers, and the lowermost layer of the electrodes is a stimulus value in the XYZ color system. Y is 4 to 15, and the average height (hc) at the center of the cross section and the maximum height (he) at the end of the cross section in the width direction of the electrode satisfy the relationship of 1 ≦ he / hc ≦ 2. This can be achieved by a display substrate characterized by the following.

Here, the lowermost layer of the electrode refers to the layer closest to the substrate among the electrode layers composed of two or more layers.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In a display on which electrodes of the present invention are formed, the electrodes are composed of at least two layers,
The lowermost layer of the electrode is black. Here, black means that the stimulus value Y in the XYZ color system is 4 to 15. The stimulus value Y is more preferably 4 to 10. If the stimulus value Y is smaller than 4, the degree of blackness is too high, and the reflection at the time of discharge decreases and the contrast decreases. On the other hand, when the stimulus value Y exceeds 15, the color becomes grayish, the reflection during non-discharge increases, and the contrast and color purity decrease. The stimulus value Y is 4 to 15, and 4
It is preferably from 10 to 10 in order to properly maintain the contrast.

The tristimulus values XYZ of the light source colors and the chromaticity coordinates x and y obtained therefrom are in accordance with JIS Z8722.
(Measurement method of object colors), is obtained by JIS Z8717 (Method of Measuring the fluorescent object color, JIS Z8701 (XYZ color system and X ₁₀ Y ₁₀ Z ₁₀ guide display colors in the color system method) in the method specified. Generally, a color computer is used as an apparatus for measuring these stimulus values and chromaticity coordinates, but the values displayed in the present invention are color computers SM-7-CH manufactured by Suga Test Instruments Co., Ltd. It was measured under the conditions of 45 ° illumination and 0 ° light reception.

Further, the OD value of the lowermost layer of the electrode of the present invention is 0.1.
It is preferably from 6 to 2.0, more preferably from 1.2 to 2.0. When the OD value is in the range of 0.6 to 2.0, the contrast can be improved, which is preferable.

The OD value here is a value measured by reflection,
When the incident light intensity is I ₀ and the reflected light intensity is I, the ratio (I / I ₀ ) = R is the reflectance, but the OD value is −lo.
It is defined by gR. A Macbeth reflection densitometer RD-918, which is a densitometer for printing, was used for the measurement. The sample used in the measurement in the present invention was obtained by applying an electrode paste on a glass substrate to a dry film thickness of 8 μm by a screen printing method, and baking it at 570 ° C. for 15 minutes to form an electrode having a film thickness of 5 μm. is there.

When the whole electrode has such a blackness, there is a disadvantage that the sheet resistance of the electrode is increased. However, when only the lowermost layer of the electrode is blackened as in the present invention, the sheet of the portion is not covered. The resistance is allowed to rise to some extent,
It may be 1 MΩ / □ or less. By setting the resistance of the other parts constituting the upper part of the electrode to 10 mΩ / □ or less, the resistance of the entire electrode can be sufficiently reduced.

The thickness of the entire electrode to be formed is 4 to 10 μm
And more preferably 4 to 7 μm. The thickness of the black portion below the electrode is preferably 2 to 5 μm, and the thickness of the other portion above the electrode is preferably 2 to 6 μm. If the thickness of the electrode exceeds 10 μm, cracks may occur in the dielectric layer due to a mismatch between the coefficient of thermal expansion of the electrode layer and the dielectric layer formed thereon and stress caused by unevenness of the electrode. The thinner the electrode is, the more economical it is, as long as it exhibits its function. However, in order to form an electrode that exhibits a stable function, it is necessary to consider processing problems.
In order to form each layer of an electrode configuration composed of two or more layers with a uniform thickness, the thickness is preferably 2 μm or more, and the total thickness of the electrode of the present invention formed of two or more layers is 4 μm.
It is preferably at least μm.

In the present invention, the thickness of the electrode is measured by the following method by setting the distance between the upper surface and the lower surface of the electrode at eleven points every 1/10 of the line width (for example, 5 μm for a line width of 50 μm). Every second) and measure the average value as the electrode thickness. That is, the cross section of the electrode formed on the substrate is observed and measured with a scanning electron microscope (for example, Model S-2400 manufactured by Hitachi, Ltd.). Alternatively, for example, a portion where the electrode surface is not covered with a dielectric layer or the like but is exposed, such as a connection portion with a drive circuit, is exposed to a stylus type roughness meter (for example, surface roughness manufactured by Kosaka Laboratory Co., Ltd.). Measure with a measuring instrument SE-3300).

Further, according to the present invention, the average height (hc) at the center of the cross section in the width direction of the electrode and the maximum height (h) at the end of the cross section are determined.
e) is a relation of 1 ≦ he / hc ≦ 2. That is, by satisfying the relationship of 1 ≦ he / hc ≦ 2 as the condition of the upper surface shape of the formed electrode, an electrode with small unevenness, a low resistance and a thin film can be obtained. The average height (hc) at the center of the cross section and the maximum height (he) at the end of the cross section are determined by a stylus type roughness meter (for example, Kosaka Co., Ltd.) from one end to the other end in the electrode width direction. The surface roughness is measured by observing with a laboratory surface roughness measuring instrument SE-3300 or a scanning electron microscope (for example, Model S-2400 manufactured by Hitachi, Ltd.). Here, the average height (h
c) is defined as a range corresponding to a length within 35% of the width to both ends with respect to the center of the width in the width direction, that is, a range corresponding to 70% of the length in the electrode width direction from the electrode formation surface of the electrode upper surface. The maximum height (he) of the cross-sectional end is within 15% of the width from both ends in the electrode width direction, that is, the center of the cross-section with respect to the cross-section in the electrode width direction. It indicates the maximum value of the distance from the electrode formation surface of the electrode upper surface in the two end ranges excluding.

If the value of he / hc is less than 1, the cross-sectional area with respect to the thickness cannot be increased, and a low-resistance electrode cannot be obtained. On the other hand, when the value of he / hc is larger than 2, the flatness of the electrode is deteriorated, which adversely affects the formability of another layer formed on the electrode, for example, a dielectric layer or a phosphor layer. For example, when the average height (hc) at the center of the cross section is 4.5 μm, and when the electrode has the maximum height (he) at the end of the cross section of 9.9 μm, the ratio of he / hc The value is 2.
2 and greater than 2, such electrodes are not the electrodes to which the present invention is directed.

In particular, when an electrode patterned using a photosensitive conductive paste method is formed, large edge curl is likely to occur. Edge curl, in the firing step in the case of forming a patterned electrode, shrinkage of the electrode caused when the organic component is thermally decomposed and removed, peel off both ends in the electrode width direction from the electrode forming surface, It is thought that it is caused by floating,
Particularly, in the photosensitive conductive paste method, a developing step is essential. At this time, a slight peeling occurs between the substrate and the electrode due to so-called side etching at both ends in the electrode width direction, and this is enlarged in the firing step. This is because a large edge curl occurs.

The thickness of the electrode after firing is preferably 4 to 10 μm, but the edge curl allowed in such an electrode is within 2 μm.

However, in particular, the value of he / hc is set to 1.
By setting the ratio to 1 or more and 2 or less, even if edge curl occurs, problems such as peeling of the electrode and cracking of the dielectric layer and the phosphor layer formed on the electrode do not occur.

When w2 / w1 is in the range of 0.7 to 1, the adhesiveness to the electrode forming surface is high, and a low-resistance and thin-film electrode can be obtained.

The width (w1) of the electrode in the width direction and the contact length (w2) of the electrode in the width direction can be determined by scanning an arbitrary cross section of the electrode in the width direction with a scanning electron microscope (for example, ) Observation with Hitachi Model S-2400), the length of the upper surface of the electrode in the width direction of the electrode is (w1), the lower surface of the electrode and the surface on which the electrode is formed, that is, the underlayer before forming the electrode on the substrate. In the case where such a layer is provided, the contact length (w2) in the width direction between the layer and the lower surface of the electrode is set.

The electrode of the present invention can be formed by applying a black paste containing black powder and a conductive paste containing conductive powder, followed by firing.

The conductive powder in the conductive paste may be a metal powder having a low theoretical resistance value which can be baked on a glass substrate at a temperature of 600 ° C. or less, but may be Ag, Au, Pd, N
Those containing at least one selected from the group consisting of i, Ti and Pt are preferred. These can be used alone, as an alloy or as a mixed powder. Examples of the mixed powder include Ag (80-98) -Pd (20-2) and Ag (9
0-98) -Pd (10-2) -Pt (2-10), A
Binary or ternary mixed metal powders such as g (85-98) -Pt (15-2) (where parentheses indicate weight%).

Among these metal powders, Ag alone can be preferably used from the viewpoint of cost and sinterability.

The inorganic components in the black paste forming the lowermost layer of the electrode of the present invention are Cr, Fe, Co, Mn, Ni, C
a black component comprising at least one metal selected from the group consisting of u and Ru and / or an oxide thereof in a total amount of 8-35.
What contains by weight is preferable. 10-3
Those containing 0% by weight are more preferable. Further, the inorganic component is a glass frit of 20 to 9 in addition to the black component.
It is preferable to contain 2% by weight.

The inorganic component in the black paste is black component 1
More preferably, it contains 0 to 30% by weight and 70 to 90% by weight of glass frit. Also, 10 to 30% by weight of a black component, 20 to 70% by weight of a glass frit, 30% of a conductive powder
It is also preferred to include a range of up to 70% by weight.

The simplest method of blending the black powder is to mix the black component and the glass frit with a ball mill or a mixer. It is more preferable to use a powder produced by melting at a temperature of not less than ° C. In the case of a black powder containing a glass frit prepared by melt mixing, the black pigment is uniformly and uniformly dispersed and dissolved, so that the particle size distribution of the pulverized black powder can be easily controlled. Further, the amount of the black pigment to be added is also preferable, as compared with the case where the paste is mixed with the paste in a powder state, since a black electrode having a small amount of uniform and high blackness without unevenness can be obtained.

It is preferable to use a plurality of types of black pigments to be simply mixed and melt-mixed, instead of one type, since a desired degree of blackness can be obtained with a small amount of addition. The total amount is 8 ~
The content of 35% by weight is preferable because it is excellent in maintaining the function of the black paste and controlling the blackness of the obtained electrode. In the case of multiple types, NiO-CoO, C
_{oO-NiO-Cr 2 O 3} , CoO-Cr 2 O 3 -Fe 2 O 3
Based oxides are preferred.

As the black powder, a powder obtained by adding a predetermined amount of black oxide fine particles to the above black powder or a single black oxide fine particle is also preferably used. Oxide fine particles are fine nanoparticles having an average particle diameter of 0.005 to 0.05 μm, and their size is smaller than the wavelength of the active light used for exposure, so that they do not hinder the transmission of light and improve the pattern formability. It can be maintained well. 0.005μ
If it is less than m, it becomes too fine and easily aggregates, and it is technically difficult to uniformly fill and disperse the paste. Therefore, the ultraviolet rays are scattered on the way without reaching the bottom of the coating film, and the pattern formability is reduced,
Sufficient blackness cannot be obtained after firing. On the other hand, 0.0
If the average particle diameter is more than 5 μm, the particles become too large to be affected by the exposure wavelength, and the pattern formability decreases, which is not preferable. When the particle size is in the above range, the particle size is smaller than the exposure wavelength of 320 to 460 nm, so that even if the particle size is dispersed in the paste, it does not significantly hinder pattern exposure. As a result, at the paste coating film stage, the paste does not adversely affect the pattern formation and effectively acts on the blackened electrode after firing.

When both the black powder and the oxide fine particles are contained, the total content in the black paste is as follows:
The content is preferably from 8 to 35% by weight, and the content of the oxide fine particles is preferably from 5 to 20% by weight. When the oxide fine particles are solely contained, the content is preferably 5 to 25% by weight, more preferably 8 to 20% by weight in the black paste. Within this range, a film having a high degree of blackness can be obtained after firing.

Further, the black paste forming the black electrode portion is preferably a photosensitive black paste containing a photosensitive organic component.

The average particle size of the conductive powder contained in both the conductive paste and the black paste is 0.5 to 3 μm, more preferably 0.5 to 2 μm. Particle size 0.5 μm
By doing so, the light transmittance at the time of pattern formation is improved, and a fine pattern with a line width of 60 μm or less of the electrode is easily formed. By setting the thickness to 3 μm or less, it is possible to prevent a decrease in pattern accuracy and thickness accuracy of the thin film conductor.

It is preferable that the particle size distribution of the conductive powder has a single peak distribution. A single peak distribution is preferable because the filling property and dispersibility of the conductive powder in the photosensitive paste are improved, the light transmittance is improved, and a highly accurate pattern can be formed.

The shape of the conductive powder is not particularly limited.
Since forming a denser conductor film lowers the resistance,
Granular or spherical particles with a large tap density are preferred.
The tap density of the conductive powder is in the range of ^{3 to} 6 g / cm ³ , more preferably 3.5 to 5 g / cm ³ . When the tap density is in this range, the transmittance of ultraviolet light used for exposure is good, and the sectional shape and accuracy of the electrode pattern are improved. Furthermore, the leveling property of the film after application of the paste is improved,
A dense film is obtained.

As the conductive powder, there are granular, polyhedral and spherical ones. However, it is preferable that the conductive powder is a monodisperse particle which does not aggregate and is spherical. In this case, the sphericity is preferably 90% by number or more. The sphericity is a ratio of spherical particles when powder is photographed with an optical microscope at a magnification of 300 times and countable particles are counted. When the shape is spherical, scattering of ultraviolet rays during exposure is reduced, and a highly accurate pattern can be obtained.

The specific surface area of the conductive powder is 0.3 to 2.5.
m ² / g is preferable, and more preferably 0.35 to
It is 2 m ² / g. If it is less than 0.3 m ² / g, the particles tend to be too large and the pattern accuracy tends to decrease. On the other hand, if it is 2.5 m ² / g or more, the surface area of the particles becomes too large, the particles are likely to aggregate, causing scattering at the time of exposure, and the photoreaction to the lower part of the paste does not proceed sufficiently.
The yield may be deteriorated due to a defective cross-sectional shape of the pattern or peeling during development.

It is preferable to add 3 to 20 parts by weight of the same kind of metal fine particles as the conductive powder to the conductive powder. The metal fine particles are fine nanoparticles having an average particle diameter of 0.005 to 0.1 μm. By being in this range, the metal fine particles enter the gaps between the conductive powders and act as sintering accelerators. Baking can be performed at a low temperature of 520 ° C.

By including a glass frit in the black electrode forming the lowermost layer of the electrode, a strong adhesive force with the glass substrate can be obtained. The glass frit preferably has an average particle size of 0.5 to 1.4 μm and a top size of 4.5 μm or less. When the average particle size is 0.5 μm or less,
The particles of the glass frit are too small to easily scatter ultraviolet rays, and a residual film may remain during development. When the average particle size exceeds 1.4 μm or when the top size exceeds 4.5 μm, the thermal expansion coefficients of the coarse glass frit and the conductive powder are different, and especially in the case of a thin film, the adhesive strength is reduced. Film peeling is likely to occur. In addition, the coarse glass frit remains in the electrode film, and the adhesive strength tends to decrease or the electrode may be disconnected, which is not preferable.

The thermal expansion coefficient alpha ₅₀ ~ ₄₀₀ in the temperature range of 50 to 400 ° C. of glass frit, 75~90 × 10 ^-7 /
It is preferably K. Since the glass substrate on which the electrodes are formed has a coefficient of thermal expansion of 80 to 90 × 10 ⁻⁷ / K, if the α ₅₀ to ₄₀₀ of the glass frit is not in this range, the conductive film baked on the glass substrate will not be in contact with the glass. Film peeling due to the difference in thermal expansion coefficient from the frit may occur during cooling.

The load softening point (also referred to as the yield point) of the glass of the glass frit is preferably in the range of 350 to 550 ° C. for firing at a low temperature. The firing of the electrode is preferably performed at a temperature in the range of 350 to 500 ° C, more preferably in the range of 350 to 450 ° C, to avoid yellowing of silver.

As the glass frit of the present invention, a glass frit containing bismuth oxide is used, and a more preferable glass frit has the following composition in terms of oxide.

Bismuth oxide 30 to 85% by weight Silicon oxide 5 to 30% by weight Boron oxide 5 to 20% by weight Zirconium oxide 3 to 10% by weight Aluminum oxide 1 to 5% by weight When such a glass frit composition is used, a photosensitive organic compound is used. A preferable glass frit can be obtained without using lead oxide or the like, which easily causes a gelling reaction of components, and it is possible to avoid a problem that the viscosity of the paste is increased or a pattern cannot be formed due to the gelling reaction, and a stable black paste can be obtained. it can.

The bismuth oxide is preferably blended in the range of 30 to 85% by weight. When the amount is less than 30% by weight, when the conductive paste is baked on a glass substrate, the glass transition point and the softening point are not sufficiently controlled, and the effect of increasing the adhesive strength of the conductive film to the substrate is small. Also 8
If it exceeds 5% by weight, the softening point under load of the glass frit becomes too low, and the glass frit melts before the binder in the paste is thermally decomposed. For this reason, the binder removal property of the paste is deteriorated, the sinterability of the conductive film is reduced, and the adhesive strength with the substrate is reduced.
Is more preferable.

It is necessary to mix silicon oxide in the range of 5 to 30% by weight. If the content is less than 5% by weight, the adhesive strength when baked on a substrate is reduced, and the stability of the glass frit is reduced. On the other hand, if it exceeds 30% by weight, the heat-resistant temperature rises, and at 600 ° C. or lower, it becomes difficult to print on a glass substrate.

It is necessary to add boron oxide in the range of 5 to 20% by weight. Boron oxide is blended in order to control the baking temperature in the range of 420 to 600 ° C. so as not to impair the properties of the conductive paste such as electrical insulation, adhesive strength, and coefficient of thermal expansion. If the amount is less than 5% by weight, the adhesion strength decreases, and if it exceeds 20% by weight, the stability of the glass frit decreases.

It is necessary to add zirconium oxide in the range of 3 to 10% by weight. Zirconium oxide improves the acid resistance of the glass frit. That is, when the glass frit composition of the present invention is used, the glass frit reacts with the photosensitive organic component to cause a gelling reaction of the paste, but the gelation is suppressed by adding zirconium oxide. If it is less than 3% by weight, the effect of suppressing gelation is small. If it exceeds 10% by weight, the heat-resistant temperature of the glass becomes too high and it is difficult to bake it on a glass substrate.

It is necessary to mix aluminum oxide in the range of 1 to 5% by weight. When the addition of aluminum oxide is in this range, the stability to gelling of the paste, the thermal stability of the glass frit, the coefficient of thermal expansion, the glass transition point,
This is preferable because the softening point under load can be controlled.

The glass frit powder should be substantially free of alkali metal oxides and / or alkaline earth metals such as sodium oxide, lithium oxide, potassium oxide, barium oxide and calcium oxide which degrade the plasma discharge characteristics. Is preferred. There is a problem that the alkali metal component and the alkaline earth metal in the glass frit react with the silver in the electrode to cause yellowing. As a cause, it is presumed that silver undergoes an ion exchange reaction with an alkali ion or an alkaline earth metal, and the silver turns into a colloid to turn yellow. Even when an alkali or alkaline earth metal oxide is contained, 0.5% by weight or less, more preferably 0.1% by weight or less.
% By weight or less.

The thermal expansion coefficient, glass transition point, and softening point under load can be controlled by incorporating titanium oxide or the like in the glass frit, but the amount is preferably less than 10% by weight.

In the present invention, a photosensitive black paste and a photosensitive conductive paste containing a photosensitive organic component are preferably used. Since these are used simultaneously in the pattern formation and baking steps, they are most preferably the same photosensitive organic components.

As the photosensitive organic component, there are a photo-insolubilizing type and a photo-solubilizing type, and both of them can be used. In the present invention, the photo-insolubilizing type is used in view of ease of handling and quality design. Is used. It is preferable to use a type containing a functional monomer, oligomer, or polymer having at least one unsaturated group in the molecule. That is,
The photosensitive organic component includes a photosensitive monomer, a photosensitive oligomer,
A binder, a photopolymerization initiator, a sensitizer, a plasticizer, a thickener, a dispersant, and other additives are added as necessary, in addition to a photosensitive component selected from at least one of the photosensitive polymers. be able to. Additives composed of photosensitive organic components and various organic components affect the properties of the electrode in connection with debinding, so the type and amount of organic components should be selected in consideration of their thermal decomposition properties. is important.

As the photosensitive monomer, a compound having an active carbon-carbon double bond is used, and a monofunctional or polyfunctional compound having a vinyl group, an allyl group, an acrylate group, a methacrylate group, or an acrylamide group as a functional group is used. Is applied. A polyfunctional acrylate compound and / or a polyfunctional methacrylate compound may
It is preferable to contain 80% by weight. Since various types of compounds have been developed as polyfunctional compounds having an acrylate or methacrylate functional group, it is possible to select from them in consideration of reactivity, developability, thermal decomposition, and the like.

The photosensitive organic component constituting the photosensitive conductive paste serves to improve the physical properties of the cured product formed by the photoreaction, adjust the viscosity of the paste, and controls the solubility of the unexposed portion. Oligomers or polymers are used as components that perform the function. These oligomers or polymers have a carbon chain skeleton obtained by polymerization or copolymerization of components selected from compounds having a carbon-carbon double bond. As the monomer to be copolymerized, unsaturated carboxylic acid or the like is useful, and a photosensitive paste which can be developed with an aqueous alkali solution after exposure to light can be provided. Specific examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, and acid anhydrides thereof.

The resulting oligomer or polymer having an acid group such as a carboxyl group in the side chain has an acid value of 50.
It is good to control so as to be in the range of 180 to 180, preferably 70 to 140. When the acid value exceeds 180,
The allowable development width is reduced. On the other hand, when the acid value is 50 or less, the solubility of the unexposed portion in the developer decreases.

In the present invention, as the photosensitive oligomer or polymer component, it is most preferable to use an oligomer or polymer having a carboxyl group and an unsaturated double bond in the molecule and having a weight average molecular weight of 500,000 to 100,000. More preferably, it is 10,000 to 50,000. To introduce an unsaturated double bond, an oligomer or a polymer having a carboxyl group in the side chain as described above, an ethylenically unsaturated compound having a glycidyl group or an isocyanate group, acrylic acid chloride, methacrylic acid chloride, or allyl chloride. Is applied. The number of carboxyl groups for developing with an aqueous alkali solution and the number of ethylenically unsaturated groups that render the oligomer or polymer photosensitive can be freely selected depending on the reaction conditions.

As a method for introducing a photosensitive reactive group into an oligomer or polymer having a carboxyl side chain, a method utilizing a salt bond is also effective.

When a binder component is required to form the photosensitive conductive paste and the black paste, polyvinyl alcohol, polyvinyl butyral, methacrylate polymer, acrylate polymer, and copolymers thereof are used. Can be used.

The organic component of the photosensitive paste of the present invention contains a photosensitive monomer, a photosensitive or non-photosensitive oligomer or polymer, but none of these components has the ability to absorb the energy of actinic light. In order to start the reaction, it is preferable to add a photopolymerization initiator or a sensitizer.

The pattern formation by the photosensitive paste is to polymerize and crosslink the photosensitive components (monomers, oligomers, and polymers) in the exposed portions to make them insoluble in a developing solution. Since it is radically polymerizable, the photopolymerization initiator is selected from those that generate active radical species. By using a sensitizer together with the photopolymerization initiator, the sensitivity can be improved (chemical sensitization) or the wavelength range effective for the reaction can be expanded (spectral sensitization).

If necessary, a plasticizer may be added to the photosensitive conductive paste and the photosensitive black paste, an antioxidant may be added to enhance the stability of the paste, and the viscosity may be increased due to the application properties of the paste. An agent can be added.

It is convenient in the process that an alkaline aqueous solution can be used as a developing solution in developing the photosensitive conductive paste and the photosensitive black paste. For this reason, the carboxyl groups in the oligomer or polymer present and the calcium frit, barium oxide, ferric oxide, magnesium oxide, etc., which are present in the glass frit in the photosensitive black paste in trace amounts, react to gel the paste in a short time. ,
There arises a problem that the viscosity increases and the paste cannot be applied as a lump. This is presumed to be gelation due to the ionic crosslinking reaction of the polymer. In order to prevent such a reaction, it is preferable to add a stabilizer within a range that does not adversely affect the gelation to prevent the gelation. That is, the powder is subjected to a surface treatment with a compound which is effective for forming a complex with a metal or metal oxide powder which causes a gelling reaction or forming a salt with an acid functional group, thereby stabilizing the photosensitive black paste. As such a stabilizer, a triazole compound is preferably used. Benzotriazole is particularly effective among the triazole compounds.

The trace amount of water contained in the photosensitive conductive paste and the black paste also promotes the gelation of the paste. In order to prevent this, it is preferable to completely dehydrate all components added as photosensitive organic components. The removal of water depends on whether it is solid or liquid.
It is performed by a molecular sieve treatment, a rotary evaporator or the like. Further, in the case of a glass frit, 150 to 3
Drying at 50 ° C. for 5 to 15 hours to sufficiently remove water is preferable because gelation can be prevented.

An organic solvent is used to adjust the viscosity when applying the photosensitive conductive paste and the photosensitive black paste to the glass substrate according to the application method. As the organic solvent used at this time, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol,
Examples include tetrahydrofuran, dimethyl sulfoxide, and γ-butyrolactone. These organic solvents are used alone or in combination of two or more.

The electrodes of the display substrate are patterned by using a conductive paste containing conductive powder as an essential component, patterned by using a photosensitive conductive paste, or formed by depositing a conductive component. It can be formed by a method of forming by sputtering or the like. In methods involving vacuum operations such as vapor deposition and sputtering, 1 μm
Although it is possible to form a low-resistance electrode with the following thin films, there is an economic problem that the cost is high. On the other hand, screen printing of a conductive paste is the most economical method, although the thickness of the formed electrode is 1 μm or more. However, the method using screen printing of a conductive paste has many problems in manufacturing electrodes for a high-definition and large-sized display as described above. In particular, the cross-sectional shape of the formed electrode in the width direction tends to be “camel-shaped”, which is not suitable for forming a low-resistance thin-film electrode.

A photolithography method using a photosensitive paste is considered to be a method of forming a patterned electrode that is economical and can cope with high definition and large size. According to this method, it is possible to form an electrode having a line width of 50 μm or less and a cross-sectional shape close to “rectangular” by a thin film.

Therefore, as a method of forming an electrode of a display having a fine pattern, a cross section in the width direction close to a “rectangular shape”, a high adhesive strength to a glass substrate, and a low resistance, the following method is used in the present invention. The method is preferred. That is, a photosensitive black paste containing a black powder is applied to form a coating film A that forms the lowermost layer of the electrode, and a photosensitive conductive paste containing a conductive powder forming the upper part of the electrode is applied thereon. To form a coating film B. After drying these, a coating film A and a coating film B are simultaneously patterned by a photolithography method and then fired to form a patterned electrode composed of at least two layers. Here, the preferable thickness of the black layer at the lowermost layer of the electrode is 2 to 5 μm as described above, the preferable thickness of the other portion on the upper side of the electrode is 2 to 6 μm, and the preferable thickness of the entire electrode is 4 to 10 μm, more preferably. 4 to 7 μm.

Further, in the display of the present invention, it is preferable that a dielectric layer is formed on the electrodes.

The electrode composed of at least two layers thus formed can be used for any of an image display device, a plasma display panel, and a plasma addressed liquid crystal display using an electron-emitting device or a fluorescent display tube.

[0076]

The present invention will be described below in more detail with reference to Examples, but it should not be construed that the invention is limited thereto. The concentrations in the examples are% by weight unless otherwise noted.

Example 1 A black powder 25 having the following composition was used as a photosensitive black paste.
%, Glass frit 40% and conductive powder Ag 35%
Was added to an organic solvent γ-butyrolactone and dissolved and kneaded in an amount of 60 parts by weight of an inorganic component and 40 parts by weight of the following photosensitive organic component. The black powder and the glass frit were used by melting and mixing.

The composition of the black powder is CoO / Cr ₂ O ₃ / M
nO ₂ / Fe ₂ O ₃ = 20/30/25/25 (%).

The composition of the glass frit is Bi ₂ O ₃ / Si
O ₂ / B ₂ O ₃ / ZrO ₂ / ZnO / Al ₂ O ₃ = 66.9 /
The product used was 10.0 / 11.8 / 4.8 / 2.6 / 2.8 (%). The glass transition point 45 of this glass frit
7 ° C., softening point 538 ° C., expansion coefficient 75 × 10 ⁻⁷ / K.

After being mixed and melted, the pulverized blackened glass frit had an average particle size of 1.1 μm, a top size of 4.4 μm, and a specific surface area of 8.4 m ² / g.

The photosensitive organic component is a photosensitive polymer (X4
007) 8 parts by weight, photosensitive monomer (trimethylolpropane triacrylate) 5 parts by weight, photopolymerization initiator (2
-Methyl-1- [4- (methylthio) phenyl] -2-
(Morpholino-propane) 2 parts by weight.

Further, as the photosensitive conductive paste, a mixture comprising 40 parts by weight of the same photosensitive component as used in the photosensitive black paste and 60% by weight of conductive powder Ag was added to the organic solvent γ-butyrolactone, and dissolved and kneaded. What was used was used.

This photosensitive black paste is 25 cm × 25
A coating film A was formed by applying a screen printing method to a soda glass substrate of cm square. The coating film was dried at 80 ° C. for 40 minutes and had a thickness of 6 μm. A photosensitive conductive paste was similarly applied on this coating film A to form a coating film B having a dry thickness of 4 μm.

A negative photomask having an electrode pattern in close contact with the coating film B (stripe pattern, line width 50
50 mW / cm through a power of 50 mW / cm
Ultraviolet light exposure was performed for 30 seconds using the ultra high pressure mercury lamp of No. ² .

The development was performed by a shower of a 0.1% aqueous solution of monoethanolamine at 30 ° C., and the unexposed portions were removed. Thereafter, the developer was washed away with a shower of pure water and dried at 80 ° C. for 20 minutes. Firing at 250 ° C /
The temperature was raised at the speed of the hour, and the maximum temperature was kept at 580 ° C. for 15 minutes.

The thus obtained electrode had a thickness of 3.1 μm at the black lower part, 2.2 μm at the white upper part, and an average thickness of the whole electrode of 5.3 μm. The specific resistance of the entire electrode was 3.0 μΩ · cm. The stimulus value Y was 5 and the OD value was 1.5 in the XYZ color system under black. The value of w2 / w1 was 0.83, and the value of he / hc was 1.7.

A dielectric layer having a thickness of 8 μm is formed on the electrode,
A display substrate was created. No defects such as cracks were found in the dielectric layer.

Example 2 Example 1 was repeated except that the black powder / glass frit / conductive powder composition of the photosensitive black paste was changed to 25/55/30.
A display substrate was prepared in the same manner as described above. The obtained stimulus value Y in the XYZ color system under the electrode is 5.5, and O
The D value was 1.4. The specific resistance of the entire electrode is 4.5μ
Ω · cm. The measured value of w2 / w1 is 1.85.
And the value of he / hc was 1.7. No defects such as cracks were found in the dielectric layer.

Example 3 Example 1 was repeated except that the ratio of black powder / glass frit / conductive powder of the photosensitive black paste was changed to 25/65/10.
A display substrate was prepared in the same manner as described above. The stimulus value Y in the XYZ color system under the obtained electrode was 7, and the OD value was 1.3. The specific resistance of the whole electrode is 10μΩ · c
m. The measured value of w2 / w1 is 0.75, h
The value of e / hc was 1.55. No defects such as cracks were found in the dielectric layer.

Example 4 NiO / CoO = 25/68 was used as the black powder composition, and black powder / glass frit / conductive powder (Ag) =
A display substrate was prepared in the same manner as in Example 1 except that the substrate was changed to 20/50/30. XY of the obtained electrode lower part
The stimulus value Y in the Z color system was 7, and the OD value was 1.4. The specific resistance of the entire electrode was 4.2 μΩ · cm.
The measured value of w2 / w1 was 0.80, and the value of he / hc was 1.69. No defects such as cracks were found in the dielectric layer.

The black powder and the glass frit used in the present example were mixed and melted, and then pulverized. The blackened glass frit used was 1.2 μm in average particle size, 4.4 μm in top size, and specific surface area in 4.4 μm. It was 8.1 m ² / g.

Example 5 A display substrate was prepared in the same manner as in Example 4 except that a black powder / glass frit = 35/65 (% by weight) and a photosensitive black paste containing no conductive powder was used. .

The stimulus value Y in the XYZ color system under the obtained electrode was 3.5, and the OD value was 1.2. The specific resistance of the entire electrode was 4.5 μΩ · cm. Measured w2
The value of / w1 was 0.86 and the value of he / hc was 1.9. No defects such as cracks were found in the dielectric layer.

Example 6 "Cyclomer P" (manufactured by Daicel Chemical Industries, Ltd., ACA210, acid value 120, molecular weight 28,000) as a photosensitive polymer of a photosensitive black paste and a photosensitive conductive paste.
A display substrate was prepared in the same manner as in Example 5 except for using.

The stimulus value Y and the OD value of the obtained XYZ color system under the electrode were 6 and 1.6, respectively. The specific resistance of the entire electrode was 3.1 μΩ · cm. W2 / w measured
The value of 1 was 0.84 and the value of he / hc was 1.7. No defects such as cracks were found in the dielectric layer.

Example 7 CoO / Cr ₂ O ₃ / MnO ₂ / Fe ₂ O ₃ as black powder
A display substrate was prepared in the same manner as in Example 5, except that a composition having a composition of 20/30/25/25 (%) was used.

The stimulus value Y in the XYZ color system under the obtained electrode was 3.0, and the OD value was 1.2. The specific resistance of the entire electrode was 4.6 μΩ · cm. Measured w2
The value of / w1 was 0.80 and the value of he / hc was 1.8. No defects such as cracks were found in the dielectric layer.

Example 8 A display substrate was prepared in the same manner as in Example 5, except that ruthenium oxide having an average particle diameter of 0.01 μm was used as the black powder.

The stimulus value Y in the XYZ color system under the obtained electrode was 2, and the OD value was 1.1. The specific resistance of the entire electrode was 4.0 μΩ · cm. W2 / w measured
The value of 1 was 0.7 and the value of he / hc was 1.6.
No defects such as cracks were found in the dielectric layer.

Example 9 A display substrate was prepared in the same manner as in Example 5, except that 15% of cobalt oxide having an average particle diameter of 0.008 μm and 20% of nickel oxide having an average particle diameter of 0.014 μm were used as black powder. did.

The stimulus value Y and the OD value of the obtained XYZ color system under the electrode were 1.3 and 1.3, respectively. The specific resistance of the entire electrode was 4.6 μΩ · cm. Measured w2
The value of / w1 was 0.75 and the value of he / hc was 1.7. No defects such as cracks were found in the dielectric layer.

Example 10 A display substrate was prepared in the same manner as in Example 4 except that Ni was used instead of Ag as the conductive powder in the photosensitive black paste. The stimulus value Y in the XYZ color system under the obtained electrode was 7, and the OD value was 1.4. The specific resistance of the entire electrode was 15 μΩ · cm. W2 / w measured
The value of 1 was 0.82 and the value of he / hc was 1.58. No defects such as cracks were found in the dielectric layer.

Average particle size of conductive powder Ni used in this example
Diameter is 1.8μm, specific surface area is 2.4m ^Two/ G, tap density
Is 3.6 g / cm^ThreeMet.

Example 11 A display substrate was prepared in the same manner as in Example 4 except that Ti (average particle size: 1.5 μm) was used instead of Ag as the conductive powder in the photosensitive black paste. The obtained stimulus value Y in the XYZ color system under the electrode is 8, and the OD value is 1.
It was 3. The specific resistance of the entire electrode was 20 μΩ · cm. The value of w2 / w1 measured was 0.82 and he / h
The value of c was 1.50. No defects such as cracks were found in the dielectric layer.

Example 12 The display substrate obtained in Example 1 was replaced with a PDP.
Front substrate.

On the rear substrate of the PDP, address electrodes having a line width and a pitch corresponding to the electrodes of the front substrate are formed by using silver paste, a dielectric layer is formed thereon, and then a pitch of 150 μm is formed. Line width 35 μm, height 130 μm
Was formed. Each phosphor layer of red (R) light emission, green (G) light emission and blue (B) light emission was repeatedly formed in the order of R, G, and B between the striped partition walls.

A front substrate and a rear substrate were sealed, a rare gas was sealed in a discharge space surrounded by partition walls, and a drive circuit was connected to complete a display. The display contrast was good, and a PDP with excellent display quality was obtained.

Example 13 The display substrate manufactured in Example 1 was used as a front substrate of a display using electron-emitting devices. A two-layer electrode having a black lowermost layer is used as a black matrix, and phosphors that emit R, G, and B light are sequentially applied between them, and a metal back that reflects the light emitted from the phosphor toward the front surface in a mirror-like manner. Was formed to produce a front substrate. As a back substrate, a substrate on which an electron source in which an electron-emitting device was manufactured was fixed, and a support frame and a spacer as an anti-atmospheric pressure support member were sealed between the front substrate and the back substrate.

The display using this electron-emitting device had excellent display contrast.

Comparative Example 1 A display device was prepared in the same manner as in Example 1 except that 6% of the black powder, 30% of the glass frit, and 64% of the conductive powder Ag were mixed with the photosensitive black paste. A substrate was created. The stimulus value Y in the XYZ color system of the lowermost layer of the obtained electrode was 30, and the OD value was 2.3. The blackness was clearly insufficient, and a sufficient contrast was not obtained.

The average particle size of the blackened glass frit obtained by mixing and melting the black powder and the glass frit used in this comparative example was 1.2 μm, the top size was 9.3 μm, and the specific surface area was 2.1 m ² / g. .

Comparative Example 2 In Example 1, 40% of the black powder mixed with the photosensitive black paste, 30% of the glass frit, and conductive powder Ag were used.
Was changed to 30%, and a display substrate was prepared in the same manner as in Example 1. In the XYZ color system under the obtained electrode, the stimulus value Y was 2, the OD value was 2.2, and the blackness was high. However, the edge curl was large and many cracks were generated in the dielectric. Contrast could not be measured.

Comparative Example 3 The average particle size of the conductive powder Ag was 3.5 μm in Example 1.
A display substrate was prepared in the same manner as in Example 1 except for using. Because the average particle size of the conductive powder is large,
The edge curl of the electrode is large. w2 / w1 was 1.3, but he / hc was 3, and the thickness 8
Cracks were observed in the μm dielectric layer.

Comparative Example 4 In Example 1, the thickness of the coating film A was 7 μm,
A display substrate was prepared in the same manner as in Example 1 except that the thickness of the substrate was changed to 8 μm. The electrode thickness after firing is 12
μm. The measured w2 / w1 value was 1.2, and he
The value of / hc was 2.3. Although a dielectric film having a thickness sufficient to cover the electrode thickness was formed, many cracks were observed.

[0115]

The display substrate of the present invention can be easily produced by using a photosensitive black paste and a photosensitive conductive paste, has good contrast, has low resistance, and has an edge curl on the formed electrode. This is a display substrate having a low yield, having no defects such as cracks in the dielectric film formed thereon, and having a good yield.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 31/12 H01J 31/12 C

Claims (19)

[Claims] 1. A display substrate in which electrodes are formed on a substrate, wherein said electrodes are composed of at least two layers, and a lowermost layer of the electrodes has a stimulus value Y of 4 to 15 in an XYZ color system, and The average height (hc) at the center of the cross section and the maximum height (he) at the end of the cross section in the width direction of the electrode are 1 ≦ he /
A display substrate, wherein the relationship hc ≦ 2 is satisfied. 2. An electrode according to claim 1, wherein an average height (hc) at the center of the cross section and a maximum height (he) at the end of the cross section in the width direction of the electrode are 1.1 ≦.
The display substrate according to claim 1, wherein a relationship of he / hc ≦ 2 is satisfied. 3. A length (w1) in the width direction of the top of the electrode and a contact length (w2) in the width direction between the electrode and the electrode forming surface of the substrate.
Satisfies the relationship of 0.7 ≦ w2 / w1 ≦ 1. The display substrate according to claim 1, wherein 4. The display substrate according to claim 1, wherein the black optical density (OD value) of the lowermost layer of the electrode is 0.6 to 2.0. 5. The display substrate according to claim 1, wherein the electrode has a thickness of 4 to 10 μm. 6. The display substrate according to claim 5, wherein the lowermost layer of the electrode has a thickness of 2 to 5 μm. 7. The display substrate according to claim 1, wherein the upper layer of the electrode except for the lowermost layer of the electrode contains a conductive metal. 8. The conductive metal is Ag, Au, Pd, Ni,
The display substrate according to claim 7, comprising at least one selected from the group consisting of Ti and Pt. 9. The conductive metal is made of Ag, Pd, Ni and Ti.
9. The display substrate according to claim 8, comprising at least one member selected from the group consisting of: 10. The electrode lowermost layer is composed of Cr, Fe, Co, Mn,
2. The display substrate according to claim 1, wherein the display substrate contains at least one metal selected from the group consisting of Ni, Cu, and Ru and / or an oxide thereof in an amount of 8 to 35% by weight. 11. The electrode lowermost layer has a glass frit of 20-7.
The display substrate according to claim 10, comprising 0% by weight and 30 to 70% by weight of a conductive powder. 12. The display substrate according to claim 11, wherein the glass frit has the following composition in terms of oxide. Bismuth oxide 30 to 85 wt% Silicon oxide 5 to 30 wt% Boron oxide 5 to 20 wt% Zirconium oxide 3 to 10 wt% Aluminum oxide 1 to 5 wt% 13. The display substrate according to claim 1, wherein a dielectric layer is formed on the electrode. 14. The display substrate according to claim 1, wherein the display substrate is used for any one of an image display device using an electron-emitting device, a plasma display panel, and a plasma-addressed liquid crystal. Display substrate. 15. A coating film A is formed by applying a photosensitive black paste containing black powder on a substrate, and a photosensitive conductive paste containing conductive powder is further applied thereon to form a coating film B. The coating film A and the coating film B are simultaneously formed by patterning by photolithography and then baked, and the stimulus value Y in the XYZ color system of the lowermost layer of the electrode is 4 to 15,
In addition, the average height (h
c) and the maximum height (he) of the section end is 1 ≦ he / hc
A method for manufacturing a display substrate, comprising a step of forming an electrode satisfying a relationship of ≦ 2. 16. The method for manufacturing a display substrate according to claim 15, wherein said photosensitive black paste contains a conductive powder. 17. The method according to claim 15, wherein the photosensitive black paste contains a glass frit. 18. The glass frit having an average particle size of 0.5 to
The method for manufacturing a display substrate according to claim 17, wherein the display substrate has a size of 1.4 m and a top size of 4.5 m or less. 19. The method for manufacturing a display substrate according to claim 15, wherein a dielectric layer is formed on the electrodes after forming the electrodes.