JP2002260562A - Printed wiring board and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board which enables prevention of separation of thick film wiring by suppressing the cracking, and an image formation device having the printed wiring board. SOLUTION: The printed wiring board has a glass layer 10 mainly consisting of glass which covers a partial region of the wiring that excludes a part of the film printed wiring but does not includes wiring end in the line width directions of the wiring, or covers at least a glass layer 10 adjacent to the end of the wiring in the width direction, when the line width of the wiring is wider than a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board using a thick wiring disposed on a substrate, and more particularly to an image forming apparatus provided with the wiring board.

[0002]

2. Description of the Related Art In recent years, thin self-luminous image display devices have been receiving attention. As the display device, for example, a plasma display panel that excites a phosphor by irradiating ultraviolet rays to the phosphor to emit light, a field emission type electron emission element or a surface conduction type electron emission element is used as an electron source, There is a flat image forming apparatus or the like that irradiates the phosphor with electrons emitted from the element to excite the phosphor to emit light.

FIG. 8 shows a schematic configuration of a surface conduction electron-emitting device. FIG. 9 is a schematic configuration diagram of an image forming apparatus using a surface conduction electron-emitting device.

FIG. 8A is a plan view of the structure of a surface conduction electron-emitting device, and FIG. 8B is a cross-sectional view of the structure of a surface conduction electron-emitting device. In the figure, 101 is an insulating substrate, 104
Is a conductive thin film, 102 and 103 are a pair of electrodes for obtaining electrical connection with the conductive thin film 104, and 105 is an electron emitting portion.

In FIG. 9, reference numeral 1005 denotes a rear plate;
6 is an outer frame, 1007 is a face plate. 100
8 is a fluorescent film, 1009 is a metal back. The outer frame, the substrate, and the connection portions of the face plate are sealed to form an envelope (airtight container) for maintaining the inside of the image display device in a vacuum. The rear plate 1005 includes a substrate 1001
Has been fixed. On this substrate 1001, N × M surface conduction electron-emitting devices 1002 are formed and arranged.
As shown in FIG. 9, the surface conduction electron-emitting device 1002 is wired by M row-directional wirings 1004 and N column-directional wirings 1003. As a method of forming a large number of row and column wirings, it is conceivable to use a printing technique which is relatively inexpensive and does not require a vacuum device and can cope with a large area.

[0006] As a printing technique, screen printing is generally used. Screen printing is, for example, a paste mixed with metal particles is used as a mask having an opening of a desired pattern as a mask, and the paste is printed and formed on a substrate as a printing object from the opening, and then baked to obtain a desired paste. This is for forming conductor wiring in a pattern.

[0007] Further, the above screen printing cannot be performed.
For the purpose of thinning the pattern and increasing the positional accuracy, a method using a photosensitive metal paste in which photosensitive properties are imparted to the paste can be used. The method using a photosensitive metal paste exposes a photosensitive paste formed on a substrate through a photomask having a desired wiring pattern, and then performs development and baking to form a desired pattern. It forms conductor wiring and the like.

[0008]

However, in the case of the above-described prior art, the following problems have occurred.

In general, when the thickness of a wiring formed on a substrate made of glass or the like is increased, a crack (hereinafter, referred to as an end crack) occurs in a glass portion at a portion where the end of the wiring contacts the substrate. A crack (hereinafter, referred to as a side crack) may occur in a direction parallel to the length direction of the wiring. In particular, when the wiring width becomes wider than a certain line width in association with the film thickness, the problem occurs remarkably.

This often depends on the nature of the paste as the wiring material, and does not depend much on a manufacturing method such as a screen printing method or a photosensitive paste method. However, a difference in wiring shape (particularly, a difference in cross-sectional shape) obtained by a difference in a manufacturing method may appear as a difference in susceptibility to cracks. Further, in the case of wiring of metal particles (for example, Ag), even if cracking does not occur in one firing, cracking may occur when firing is repeated in a subsequent step or the like, or for a certain period of time. However, there is a problem that cracks occur after passing through. Further, there is a problem that the end cracks and the side cracks expand and fuse, respectively, and the wiring itself warps in a strip shape and peels off.

In general, there are a plurality of possible causes of the occurrence of cracks. One of the possible causes is a difference in thermal expansion coefficient between the substrate and the wiring material. For example, when a glass-based substrate is used as the substrate, the difference in the thermal expansion coefficient between the metal-based wiring material and the glass substrate is approximately one digit larger for the wiring material. Therefore, when the wiring is baked and returned to room temperature, strain energy is accumulated between the substrate and the wiring, stress is concentrated on the substrate-side edge of the wiring, and there is a possibility that cracks may develop in the substrate.

FIG. 1 shows a state in which such cracks occur.
In the state where a plurality of strip-shaped thick film wirings 1 are formed on a glass substrate 2 and fired, FIG.
As shown in (a), side cracks 3 may occur substantially parallel to the length direction of the wiring. Side cracks almost depend on the film thickness, and the thicker the film thickness, the higher the probability of occurrence of cracks.

Also, the cross-sectional shape of the wiring is affected. In the case of the photosensitive paste method, the cross-sectional shape of the wiring is substantially trapezoidal and the sides are slightly thicker. Often there are two on each side of the inside.

Further, as shown in FIG. 11 (b), which is an enlarged view of the portion (b) of FIG. 10 from the back surface, an end crack 4 occurs along with a shell-like crack pattern at the end of the wiring. May be. Edge cracks also depend substantially on the film thickness, and the larger the film thickness, the higher the probability of occurrence of cracks.

FIG. 11C shows the wiring peeling 5 in the AA section when the wiring of FIG. 10 is viewed from the side.
As described above, the side cracks may extend and fuse (integrate) with the end cracks, resulting in large peeling of the wiring.
Again, the probability of occurrence increases as the film thickness increases, and the probability of occurrence increases as the number of firings increases.

According to the study of the present inventors, the film thickness after firing at which cracks and wiring peeling that cause problems may occur at around 5 μm, and especially at around 10 μm.
As the film thickness increases to 12 μm, 18 μm, or the like, the probability of occurrence of cracks and peeling of wiring and the degree of cracks and peeling increase.

According to the study of the present inventors, the line width at which cracks and peeling of the wiring occur may occur at a line width of about 15 μm or more when the line width exceeds 100 μm, and particularly at a line width of 200 μm. In the case of exceeding, the probability of occurrence of cracks and peeling of wiring is considerably increased.

Further, in the study of the present inventors, on a soda lime glass, a non-alkali glass, or a PD200 glass used for a PDP (plasma display panel), a silver paste having a firing process temperature adjusted for the glass is used. In combination, the line width 2
When the thickness exceeds 00 μm, almost 100% cracks occur.

If end cracks or side cracks occur as described above, in the lead-out portion of the wiring, in the flexible mounting or the tab mounting performed in a later step, the flexible or tab is peeled off together with the wiring and cannot be mounted. Edges are curled up, short-circuits due to contact with other parts, short-circuits due to crossing / dropping, problems with the shape of various markers such as alignment marks, and cracks on the board even at locations away from the ends of the wiring In the worst case, there is a problem that the wiring is peeled off and rises from the substrate, thereby impairing the reliability of the product.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to suppress cracks in a thick-film wiring and prevent wiring peeling caused by the cracks. To provide a wiring substrate and an image forming apparatus provided with the wiring substrate.

[0021]

In order to achieve the above object, according to the present invention, there is provided a wiring substrate having a plurality of thick-film wirings arranged on a substrate, wherein the wiring substrate is mainly composed of glass, When the width is equal to or more than a predetermined value, it covers an area excluding a partial area not including the wiring end in the line width direction of the wiring, or at least covers a glass layer adjacent to the wiring end in the line width direction of the wiring. It is characterized by having.

Here, in the present invention, “wiring” means a conductive material formed on a desired substrate (hereinafter, “substrate” is used in the same meaning) with a desired line width, film thickness and length. Object. The term “thick film wiring” in the present invention refers to a wiring having a thickness of 1 μm or more.

With such a configuration, it is possible to realize a thick film wiring board having an extremely high effect of suppressing end cracks and side cracks.

It is also preferable that the partial region is a connection portion that is electrically connected.

Preferably, the predetermined value is 200 μm.

It is preferable that the glass layer is made of an insulating paste having an insulating property.

It is also preferable that the insulating paste has photosensitivity.

The wiring material for the wiring arranged on the substrate is preferably a metal paste containing metal particles as a main component.

The metal paste preferably contains silver as a main component.

In the image forming apparatus, the wiring substrate described above, an electron-emitting device wired by the wiring substrate, and an image-forming member for forming an image by electrons emitted from the electron-emitting device are provided. It is characterized by having.

[0031]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, the shape, and the relative arrangement thereof should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions, and are not intended to limit the scope of the invention to the following embodiments.

The wiring board to which the present invention is applied is provided with a glass layer formed on the wiring, and the glass layer formed on the wiring having a wiring width equal to or more than a predetermined value is formed on the wiring pattern. Or overlaps or is adjacent to.

Specifically, in a thick-film wiring board having a plurality of thick-film wirings arranged on a substrate, when the wirings are viewed from above in a plan view, cracks tend to occur in each of the wirings. For a wiring pattern having a thickness, for a pattern having a predetermined line width or more, a part or all of the part is provided with a glass layer containing glass as a main component, and the glass layer is At least adjacent to the wiring pattern in the line width direction of the wiring, or overlapped with the wiring in the line width direction of the wiring (the glass layer is a partial region not including the wiring end in the line width direction of the wiring) Is covered). In other words, the part for the purpose of electrically connecting the wiring has a part where the wiring is partially exposed as a partial region, and the other part covers the glass layer partially, adjacently, or entirely. There is a feature.

Here, in this embodiment, "wiring"
The term “conductive” refers to a conductive object formed on a desired substrate (hereinafter, “substrate” is used in the same sense) with a desired line width, film thickness, and length. The term “thick film wiring” means that the thickness is 1 μm.
Refers to the above wiring.

As described above, in the present embodiment, the provision of the glass layer provides a wiring that can suppress the occurrence of side cracks and edge cracks.

When the wiring is viewed from above in a plan view, the glass layer is often formed integrally with the wiring so as to cover the wiring or to be adjacent to the end of the wiring except for the electrically connected portion. ,
Further, the glass layer is preferably formed at least in a portion having a predetermined line width or more where cracks in the wiring are likely to occur, and the shape and thickness of the glass layer may be reduced in portions where electrical connection is required. Any shape or film thickness may be used as long as the connection is not hindered. That is, the glass layer may be integrated with a part of the wiring in the line width direction.

The predetermined value of the line width of the wiring depends on the characteristics of the wiring material to be used, the characteristics of the base material for forming the wiring, the manufacturing process, and the like, and cannot be determined unconditionally. As a result of examining several types of manufacturing processes using a vitreous material for the base and using several types of pastes as the wiring material, in a wiring having a thickness of several μm to several tens of μm, the line width of the wiring is approximately 200 μm or less, and If the thickness is about 15 μm or less, it has been confirmed that side cracks and edge cracks are unlikely to occur on the substrate, so the predetermined value of the line width of the wiring forming the glass layer is 200 μm.
m or more. In the experiments of the present inventors, since the occurrence of cracks could be suppressed with a high probability if the interval between the wirings was about 100 μm or less, the width of the wiring covered with the glass layer is more preferably 100 μm or more.

Various forming methods can be applied as an example of the process for producing the above glass layer. As an example of a more optimal manufacturing method, a method using a photosensitive paste can be applied. In this method using a photosensitive paste, an insulating paste is formed on a substrate as a glass layer with respect to a wiring formed in advance on a substrate, and consideration is given so that a glass layer is formed in a desired shape on the wiring in advance. Prepare a photomask
Using a method of irradiating the insulating paste material with light through this photomask, a wiring having a glass layer in which a part of the wiring is exposed so as to be able to be electrically connected is formed through processes such as development and baking. Is what you do.

As an example of another process for producing a glass layer, a screen printing method can be applied. The screen printing method uses a plate in which a pattern similar to the desired glass layer is formed in advance, and uses a method in which an insulating paste material is discharged from this plate to form a pattern on a substrate or wiring, and thereafter, The glass layer is formed through a process such as firing.

Further, in the method using a photosensitive paste, the screen printing method, or a method combining these methods, which is described as an example of the wiring formation, the formation of the glass layer is divided into several layers to form a desired film. A forming method that takes a method of increasing the thickness is also applicable.

The wiring material used in the screen printing method is prepared using a metal paste, and the main component of the metal is a single material or a mixed material suitable for a wiring material of copper or silver having a relatively low specific resistance. I do. In particular, when a metal paste whose main component is silver is used, the printability is good and the paste can be produced without concern for the atmosphere during firing, which is convenient.

Also, the wiring material in the method using the photosensitive paste is prepared by using a metal paste, and the main component of the metal is a single material or a mixed material suitable for a wiring material of copper or silver having a relatively low specific resistance. Use something. Above all, when a metal paste whose main component is silver is used, if a screen printing method is used for film formation, printability is good and the film can be produced without concern for the atmosphere during firing, which is convenient.

The wiring of this embodiment has a thickness of 1
It is desirable to apply the present invention to a thick wiring having a thickness of at least 5 μm, preferably at least 5 μm.

This is because the composition is slightly influenced by the composition of the metal paste to be used, the composition ratio of the contents, and so on.
The state of various substrates such as a substrate coated with a surface such as SiO ₂ or a solid substrate varies depending on the substrate.
When the film thickness is about 0 μm, the possibility of occurrence of edge cracks and side cracks increases in the wiring mainly composed of silver. This is because the possibility of occurrence of cracks in firing several times, such as during formation or formation of the upper wiring, is further increased.

In particular, when the film thickness exceeds about 12 μm and reaches a film thickness of 18 μm or the like, the probability of occurrence of cracks is extremely high. On the contrary, even if the film thickness is about 5 μm to 10 μm, cracks may occur depending on the conditions. It is.

As an example, FIG. 1 is a diagram showing an example of a wiring which best shows the characteristics of a notched wiring according to the present embodiment, wherein 10 is a glass layer, 11 is a wiring, 12 is a substrate,
Reference numeral 15 denotes an electrical connection portion, and A denotes a wiring width. The figure shows that the electrical connection portion 15
This is an example in which a glass layer 10 is formed while leaving the wiring, and a diagram showing a specific form of a wiring having a glass layer according to the present embodiment.

The thick film wiring board manufactured by the above-described method is within the scope of the present invention, and a flat plate image forming apparatus manufactured using the substrate is also within the scope of the present invention.

The flat image forming apparatus using the thick film wiring board and the manufacturing method as described above has a structure in which electrons are accelerated by the display method to emit a phosphor as an image forming member, that is, At least the electron-emitting device and the phosphor are arranged in the image forming apparatus, and can be used in an image forming apparatus that requires a vacuum to emit electrons into space. The electron-emitting device is preferably used in an image forming apparatus using a surface conduction type.

A plurality of causes that can suppress the side cracks and edge cracks as described above can be presumed. The stress concentrated on the edge portion of the wiring is covered by the glass layer so that the stress is reduced in shape. What you can do,
The glass layer has a coefficient of thermal expansion that is much closer to the substrate than the metal-based wiring material, and the stress resulting from the sintering force generated during the firing of wiring can be reduced by adding a glass-based paste. It can be estimated that the effect is due to factors.

[0050]

The present invention will be described below in detail with reference to examples.

Example 1 FIGS. 2 to 5 show a method of forming a matrix wiring by forming a lower wiring and an upper wiring on a substrate as wiring patterns of an image forming apparatus.

11 is a lower wiring, 10 is a glass layer, 12 is a substrate, 13 is a mask, 14 is a paste, 15 is an electrical connection, 16 is an insulating layer, 17 is an upper wiring, and 17b is a lower wiring step. Reference numeral 18 denotes a screen plate, and reference numeral 19 denotes light (exposure light, laser light).

FIG. 2A shows a state after the lower wiring step is performed.
Further, FIG. 3 shows an AA cross section of FIG.
3A shows a state after the photosensitive paste is formed, FIG. 3B shows a state after exposure, FIG. 3C shows a state after development, and FIG. 3D shows a state after baking. FIG. 4 shows a state after the insulating layer process is performed.
4B shows a state after the upper wiring step is performed, and FIG.
5A is a cross-sectional view taken along the line AA, and FIG.
It is A sectional drawing.

First, in FIG. 3, the lower wiring 11 is formed on the substrate.
Will be described. In FIG. 3, reference numeral 12 denotes two kinds of substrates, a substrate using soda-lime glass and a substrate using PD200, and using a photosensitive paste by a screen printing method as a film forming method on each substrate. Was formed.

The photosensitive paste contains silver as a main component and contains about 60 to 80% of silver particles.
Those containing about 20 to 40% of an organic component including a photosensitive component, a glass frit, and a solvent component were used.

Plates having a roughness of about # 150 to # 400 are selectively used so as to obtain a desired final film thickness.
Film formation was performed using a plate having a roughness of 50. Thereafter, drying was performed at about 80 to 150 ° C. for the purpose of drying the photosensitive paste. The film thickness after drying was about 30 μm. In addition,
# 150 means that the number of sieves in one side of 25.4 mm is 150.

Next, in FIG. 3B, the wiring width of the lead portion having the pattern as shown in FIG.
Using a mask 13 having a pattern of 0 μm, the paste 14 was aligned and exposed so as to expose a desired place.

Next, as shown in FIG. 3 (c), the wiring paste was developed to form a wiring pattern, and this was used as a firing step as shown in FIG. 3 (d). The pattern after the firing step was slightly contracted, so that the lower wiring 11 having a wiring width of 280 μm and a height of 15 μm could be formed.

Next, as shown in FIG. 4, four layers of insulating paste are similarly formed by the photosensitive paste method.
As described above, the insulating layer 16 was formed. The photomask used at this time is the electric connection portion 1 of the wiring 11 and the wiring 17.
A glass layer 10 as shown in FIG. 4 was formed on a portion of a wiring having a predetermined value or more (that is, a lead wiring) using a pattern capable of covering the lead portion except 5.

Further, in FIG. 5, the upper wiring 17 was formed by a screen printing method. In the screen printing method, a paste containing silver as a main component and containing about 60 to 80% of silver particles was used as a paste.

A plate having a roughness of # 150 to 400 is selectively used depending on a desired final film thickness. Printing was performed using a plate having a roughness of # 150. Thereafter, drying was performed at about 80 to 150 ° C. for the purpose of drying the paste. The film thickness after drying was about 30 μm.

After the firing step, the upper wiring 17 was formed as a wiring as shown in FIG. The firing at this time is 4
The test was performed at around 20 ° C. The pattern after the firing step is slightly contracted, so that the wiring width is about 280 to 290 μm,
The upper wiring 17 having a height of about 18 μm was formed.

In this manner, a glass layer was formed on the wiring on the substrate, an upper wiring was formed, and a matrix wiring was formed.

When a wiring having a glass layer as in this embodiment was used, no side crack or edge crack occurred on any substrate regardless of the type of the substrate, and no wiring peeling or the like occurred. Was.

Further, at the end of the pattern shown in FIG. 5A, the portion other than the connection portion is covered with the glass layer, so that the strain energy of the Ag wiring is reduced, the effect of relaxing the stress is high, and the generation of cracks is suppressed. Did not.

Embodiment 2 FIG. 6 is an example of another pattern of the glass layer of the wiring board according to Embodiment 2 of the present invention.

10 is a glass layer, 11 is a wiring, 12 is a substrate, and 15 is an electrical connection.

This was produced in the same manner as in Example 1.

When a wire made of a strip-shaped glass layer pattern as in this embodiment is used, even if shrinkage due to firing occurs in the process of forming the glass layer, the glass layer is formed on the edge portion in the width direction of the wire. Since it can be formed properly without separation, the reliability for the effect of suppressing cracks in the wiring was high.

(Embodiment 3) FIG. 7 is an example of another pattern of a glass layer of a wiring board according to Embodiment 3 of the present invention.

Reference numeral 10 denotes a glass layer, 11 denotes a wiring, 12 denotes a substrate, and 15 denotes an electrical connection.

This was produced in the same manner as in Example 1.
However, only the first layer is used for the glass layer pattern, and the second and subsequent layers are masked using only the insulating layer pattern without the glass layer pattern, and the height of the wiring is adjusted to be substantially the same as the height of the glass layer. Was.

When a wiring in which a glass layer is formed so as to be adjacent to the wiring is used as in this embodiment, the connecting portion between the glass and the wiring can be made flat. A product having high strength and high reliability of electrical connection was produced.

(Embodiment 4) Embodiment 4 shows an example in which non-alkali glass is used for substrate 12 instead of the substrate (soda lime glass and PD200) used in Embodiment 1.

The alkali-free glass has a very small alkali content with respect to soda-lime glass and PD200, and therefore has a thermal expansion coefficient of about half (30 to 50 × 10 ^-7 /
K) glass. For this reason, a glass paste having a coefficient of thermal expansion as close as possible to the substrate was used as the glass paste, and was produced in the same manner as in Example 1. further,
The completed substrate was used as a substrate for a flat plate image forming apparatus.

When a wiring in which a wiring and a glass layer were formed on non-alkali glass as in this example was used, a crack was not generated on the substrate, and an effect of suppressing the wiring crack was obtained. As a flat plate-shaped image forming apparatus, an apparatus having improved reliability of the mounting portion and reliability as an airtight container could be manufactured because cracking of the substrate was suppressed.

According to the above-described embodiment, it is possible to realize a thick-film wiring board having an extremely high effect of suppressing end cracks and side cracks. In the wiring board to which the present invention is applied, side cracks and edge cracks are suppressed,
As a result, the present invention can be applied to a device having a thick film wiring which can be used for various applications satisfying the performance. In addition, a highly reliable product can be provided because a wiring without peeling can be manufactured, which is very advantageous in a process such as flexible mounting.

[0078]

As described above, according to the present invention,
In a thick-film wiring, cracks can be suppressed from occurring, and the wiring can be prevented from peeling off due to the cracks.

Therefore, in the lead-out portion of the wiring, the problem that the flexible or tab is peeled off together with the wiring in the flexible mounting or the tab mounting and the mounting cannot be performed can be eliminated. Eliminate short-circuit problems caused by contact with parts
Since there is no dropout, it is possible to eliminate the problem of short-circuit and the problem of unstable shape of various markers such as alignment marks.

Further, since cracks do not occur in the substrate even at a position distant from the edge of the substrate, the wiring does not peel off and does not float off the substrate, so that the reliability of the product can be greatly improved.

Therefore, it is possible to provide a high quality image forming apparatus with improved reliability.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a wiring board to which the present invention is applied.

FIGS. 2A and 2B show Example 1 of the present invention, wherein FIG. 2A shows a state after a lower wiring step is performed, and FIG. 2B shows a mask.

FIG. 3 shows an AA cross section of FIG. 2 (a), and FIG.
FIG. 3B is a diagram showing a state after film formation of a photosensitive paste, (b) shows a state after exposure, (c) shows a state after development, and (d) shows a state after baking.

4A and 4B show Example 1 of the present invention, wherein FIG. 4A is a diagram showing a state after an insulating layer process is performed, and FIG. 4B is a cross-sectional view taken along line AA of FIG.

5A and 5B show Example 1 of the present invention, in which FIG. 5A is a diagram showing a state after an upper wiring step is performed, and FIG. 5B is a cross-sectional view taken along line AA of FIG.

FIG. 6 is a diagram showing another example of the pattern of the glass layer of the wiring board according to the second embodiment of the present invention.

FIG. 7 is a diagram showing another example of the pattern of the glass layer of the wiring board according to the third embodiment of the present invention.

FIG. 8 is a schematic view showing an example of a surface conduction electron-emitting device.

FIG. 9 is a schematic configuration diagram illustrating an example of an image display device using a surface conduction electron-emitting device.

FIG. 10 is a diagram illustrating a conventional wiring board.

11A is an enlarged view of a portion (a) of FIG. 10 from the back surface, FIG. 11B is an enlarged view of a portion (b) of FIG. 10 from the back surface, and FIG. FIG. 11 is a diagram for explaining the peeling of the wiring in the AA cross section when the wiring of FIG. 10 is viewed from the side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thick film wiring 2 Substrate 3 Side crack 4 Edge crack 5 Wiring peeling 10 Glass layer 11 Wiring 12 Substrate 13 Mask 14 Paste 15 Electrical connection 16 Insulating layer 17 Upper wiring 18 Screen plate 19 Light (exposure light, laser light) DESCRIPTION OF SYMBOLS 101 Insulating substrate 102, 103 Device electrode 104 Conductive thin film 105 Electron emission part 1001 Substrate 1002 Surface conduction type electron emission element 1003 Column wiring 1004 Row wiring 1005 Rear plate 1006 Outer frame 1007 Face plate 1008 Fluorescent film 1009 Metal back

Continuation of front page (72) Inventor Yasuyuki Watanabe 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 5C031 DD17 5C036 EE14 EE19 EF01 EF06 EF09 EG12 EH06 5C094 AA31 AA36 AA42 AA43 AA48 BA04 BA32 BA34 CA19 DA13 DA15 DB02 DB04 DB05 EA04 EB03 FA01 FA02 FB02 FB12 FB15 GA10 GB10 JA08 5E314 AA08 BB06 BB11 CC01 CC07 DD06 DD07 FF03 FF14 GG12

Claims (8)

[Claims] 1. A wiring board having a plurality of thick-film wirings arranged on a substrate, wherein when the wiring is made of glass as a main component and the line width of the wirings is a predetermined value or more, the wiring ends in the line width direction of the wirings. A wiring layer, which covers a region excluding a partial region that does not include a glass layer, or includes at least a glass layer adjacent to a wiring end in a line width direction of the wiring. 2. The wiring board according to claim 1, wherein the partial region is a connection portion that is electrically connected. 3. The wiring board according to claim 1, wherein the predetermined value is 200 μm. 4. The wiring board according to claim 1, wherein the glass layer is made of an insulating paste having an insulating property. 5. The wiring board according to claim 4, wherein the insulating paste has photosensitivity. 6. The wiring substrate according to claim 1, wherein a wiring material of the wiring arranged on the substrate is a metal paste containing metal particles as a main component. 7. The wiring board according to claim 6, wherein the metal paste contains silver as a main component. 8. An image forming apparatus comprising: the wiring substrate according to claim 1; an electron-emitting device wired by the wiring substrate; and an image forming device that forms an image using electrons emitted from the electron-emitting device. An image forming apparatus comprising: a member;