JPH09283062A - Image forming device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device, wiring board and a method of manufacturing these device and board capable of easily repairing a short defect by current carrying repair, even when the short defect is generated in a crossing part of wiring, and capable of performing manufacture in good yield rate by reducing a cost without increasing a number of processes. SOLUTION: In this device, a plurality of electron emitting elements comprising an electron emitting part 005 and a pair of element electrodes 002, 003 are arranged in a matrix shape, in order to drive the concerned electron emitting element, an element substrate 001, formed by insulating a plurality of X, Y directional wirings (lower/upper wiring) 72, 73 formed of a thick film connected to element electrodes 002, 003 by an interlayer insulating layer 76 in a crossing part of the wirings, is used. Here, at least one of the X, Y directional wirings 72, 73 is divided into a plurality in the crossing part.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an image forming apparatus and a wiring board using an electron source substrate using thick film wiring, and a manufacturing method thereof.

[0003]

2. Description of the Related Art Conventionally, two types of electron-emitting devices are known, which are roughly classified into a hot cathode electron-emitting device and a cold cathode electron-emitting device. Among them, the cold cathode electron-emitting device is a surface conduction electron-emitting device, a field-emission electron-emitting device (hereinafter referred to as “FE type”), a metal / insulating layer / metal-type electron-emitting device (hereinafter referred to as “MIM type”). , Etc.) are known. As an example of the surface conduction electron-emitting device type, see,
I. Elinson, Radio Eng. Elect
ron Phys. , 10, 1290 (1965) and the like and other examples described later. In the surface conduction electron-emitting device, electrons are emitted by passing a current through a thin film of a small area formed on a substrate in parallel with the film surface. Examples of the surface conduction electron-emitting device include a device using an SnO ₂ thin film by Elinson et al. And a device using an Au thin film [G. Dittmer: Thin Solid Fil
ms, 9, 317 (1972)], In ₂ O ₃ / SnO
₂ Thin film [M. Hartwell and C.I.
G. FIG. Fonstad: IEEE Trans. ED C
onf. , 519 (1975)], a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, page 22 (1983)] and the like. Since this surface conduction electron-emitting device has a simple structure and is easy to manufacture,
There is an advantage that many elements can be arrayed over a large area. Therefore, applied research on charged beam sources, display devices, and the like, which make use of this feature, has been conducted. As an example in which a large number of surface conduction electron-emitting devices are formed in an array, as will be described later, surface conduction electron-emission devices are arranged in parallel, which is called a ladder-type arrangement, and both ends of each device are wired (also called common wiring). , An electron source in which a large number of connected lines are arranged. (For example, JP-A-64-031332 and JP-A-1-28374.
(9, JP-A-2-257552, etc.) In particular, in image forming apparatuses such as display devices, flat panel display devices using liquid crystal have become popular in recent years in place of CRTs. There are problems such as having to have it, and development of a self-luminous display device has been desired. An example of the self-luminous display device is an image forming device which is a display device in which an electron source having a large number of surface conduction electron-emitting devices arranged therein and a phosphor that emits visible light by electrons emitted from the electron source are combined. . (For example, U
(SP5066883)

[0004]

However, there are the following problems in increasing the area of the surface conduction electron-emitting device as described above as an image display device. When a thin film is used for an electrode or a wiring pattern in the manufacturing process of the surface conduction electron-emitting device, a metal thin film of the electrode and the wiring material is formed on the substrate by vacuum vapor deposition or the like. This is subjected to pattern processing using ordinary photolithography and etching techniques to form electrodes and wiring patterns. However, for example, when manufacturing by photolithography and etching technology on a large substrate of 40 cm square or more,
In addition to vapor deposition equipment, large-scale manufacturing equipment including exposure equipment, etching equipment, etc. are required, and not only enormous cost is required, but also when the substrate is enlarged, it is difficult to enlarge the manufacturing equipment itself, and the manufacturing method or cost. There was a problem above. In addition, the increase in the area leads to an increase in the number of electrodes, an increase in the number of wirings, and a complication, resulting in an increase in the number of steps, a defect such as a disconnection or a short circuit is likely to occur, and there is a problem that the yield is reduced. In addition, the wiring length is increased due to the increase in area, and it is necessary to make the wiring thin in order to perform high-density wiring.
When a thin film having a thickness of about m is used, an increase in wiring resistance may be a problem. As a means for producing an electron source substrate in an image forming apparatus, a printing method of a conductor paste and an insulator paste is used for some or all of the steps in place of the photolithography method, and wiring made of a thick film of several μm to several tens of μm is used. When used, compared with the photolithography method, it is possible to easily increase the film thickness, reduce the resistance of the wiring, and manufacture at a low cost. Conventionally, an energization method in which a large current is caused to flow between short-circuited wires has been used in order to repair a short-circuit defect generated between the wires. However, the wiring formed by the printing method is thick, and in particular, a short-circuit defect that occurs in the interlayer insulating portion at the intersection of the wiring arranged in a matrix may reduce the resistance in some cases. In that case, not only the short-circuited portion but also the wiring itself may be broken. The present invention
Even if a short-circuit defect occurs at an intersection of wirings, the short-circuit defect can be easily repaired by energization repair, and an image forming apparatus and a wiring board which can be manufactured at low cost with a high yield without increasing the number of steps, and manufacturing thereof. The purpose is to provide a method.

[0005]

That is, according to the present invention, in a wiring board having a plurality of intersecting wirings made of a thick film, and the intersecting portions between the wirings are insulated by an interlayer insulating layer, the intersecting wirings are , At least at the intersection, the wiring board is divided into a plurality of lines.

Further, according to the present invention, a plurality of electron-emitting devices each having an electron-emitting portion and a pair of device electrodes are arranged in a matrix, and a plurality of thick films are connected to the device electrodes for driving the electron-emitting devices. In the image forming apparatus using the electron source substrate, the X-direction wiring (lower wiring) and the plurality of Y-direction wirings (upper wiring) are insulated by the interlayer insulating layer at the intersection of the wirings. X-direction wiring and Y
At least one of the directional wirings is divided into a plurality of lines at least at the intersection portion, and relates to an image forming apparatus.

Furthermore, the present invention is a method of manufacturing a wiring board having a plurality of intersecting wirings made of a thick film, wherein the intersections between the wirings are insulated by an interlayer insulating layer, and at least one of the intersecting wirings. The wiring is divided into a plurality of lines at least at the intersecting portion, and when there is a short circuit between the wiring at the intersecting portion, a large current is caused to flow between the two wirings intersecting at the shorting portion to reduce the short circuit. The present invention relates to a method for manufacturing a wiring board, which is characterized by repairing.

Further, according to the present invention, a plurality of electron-emitting devices each having an electron-emitting portion and a pair of device electrodes are arranged in a matrix, and a plurality of thick films are connected to the device electrodes for driving the electron-emitting devices. Method for manufacturing an image forming apparatus using an electron source substrate in which the X-direction wiring (lower wiring) and the plurality of Y-direction wirings (upper wiring) are insulated from each other by an interlayer insulating layer at intersections of the wirings 2. At least one of the X-direction wiring and the Y-direction wiring is divided into a plurality of lines at least at the intersection, and when there is a short between the wirings at the intersection, the two intersect at the short portion. The present invention relates to a method for manufacturing an image forming apparatus, characterized in that a large current is passed between the wirings of a book to repair the short circuit.

When the intersecting wirings are short-circuited at the intersecting portions, if at least one of the wirings is divided into a plurality of wirings at the intersecting portions as in the present invention, a repairing method of applying a large current is used. However, the short-circuited portion can be repaired without breaking the wiring. In other words, even if the wiring breaks due to a minute breakage caused by the application of a large current, it is only necessary to break some of the divided lines, and the remaining split lines maintain the electrical signal supply. Is. Since the electron source substrate of the image forming apparatus has a large number of wirings intersecting with each other, applying this method is particularly preferable because a lower cost image forming apparatus can be manufactured with high yield.
In the description of the present invention, the X-direction wiring is referred to as the lower wiring and the Y-direction wiring is referred to as the upper wiring for the sake of convenience. However, it is within the scope of the present invention whether the wiring in any direction is the lower wiring or the upper wiring.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an electron source substrate of an example of the image forming apparatus of the present invention. This is an example in which a surface conduction electron-emitting device is used as the electron-emitting device, but the electron-emitting device to which the present invention can be applied is not limited to the surface-conduction type, and a field emission type, MIM type, semiconductor electron source, or the like can be applied. is there. In FIG. 1, 001 is a substrate made of an insulator, 00
Designated by reference numeral 20033 are element electrodes for obtaining electrical connection.
Reference numeral 004 is a conductive thin film. In this surface conduction electron-emitting device, the pair of device electrodes 002 and 003 have an electrode interval of several μm to several hundred μm and a film thickness of several hundred angstroms to several thousand angstroms, and are formed by a vacuum deposition method or a sputter deposition method. The formed metal thin film is patterned by a photolithography method or is appropriately formed by a printing method or the like.

The thickness of the conductive thin film 004 is preferably set in the range of several tens of angstroms to several thousands of angstroms, and the conductive thin film 004 is patterned by photolithography, printing method or the like, and is individually separated. ing. 72 is X connected to the device electrode 002
Directional wiring (lower wiring). 76 is an interlayer insulating layer,
It is provided at the intersection of the X-direction wiring (lower wiring) 72 and the Y-direction wiring (upper wiring). Reference numeral 73 is a Y-direction wiring (upper wiring), which is connected to the element electrode 003, and which is located on the interlayer insulating layer 76 and which has the X-direction wiring (lower wiring) 7
It intersects with 2. Although the Y-direction wiring (upper wiring) is divided into two lines in FIG. 1, the present invention is not limited to this, and it is sufficient that the Y-direction wiring (upper wiring) is divided into a plurality of lines at least at the intersections. For example, as shown in FIG. It should be divided into. Although the number of divisions is not limited, it is practically 2 to 5, preferably 2 to
There are three. Each of the X-direction wiring, the Y-direction wiring, and the interlayer insulating layer is a thick film having a film thickness of several μm to several tens μm, and is formed by a so-called thick film forming technique such as screen printing. Reference numeral 005 denotes an electron emitting portion, which is an extremely minute crack formed in the conductive thin film 004. With the above structure as a unit, this is one surface conduction electron-emitting device 7
4, and a large number of these are provided on the substrate 001 to form the electron source substrate 71.

The method of manufacturing the electron source substrate of this embodiment will be described below with reference to FIGS. A conductive film made of a metal material is printed on the well-cleaned substrate 001 to form element electrodes 002 and 003 (FIG. 9A). Next, a conductive paste is printed, and wiring in the X direction (lower wiring) 7
Form 2 These X-direction wirings (lower wirings) 72 are arranged so as to be in contact with part of the device electrodes 002 (FIG. 8B). An insulating paste is printed and baked on this, and an interlayer insulating layer 16 is formed at a position where it intersects with a Y-direction wiring (upper wiring) to be formed later (FIG. 7C). In addition, here, the interlayer insulating layer 16 includes an X-direction wiring (lower wiring) 72 and a Y described later.
Although it was formed only at the intersection with the direction wiring (upper wiring) 73,
The invention is not limited to this, and may be formed over the entire lower portion of the Y-direction wiring, for example.

Next, as shown in FIG. 3D, a conductive paste is further printed and baked on the interlayer insulating layer 16 to form two Y-direction wirings (upper part) which is the main constitution of the present invention. Wiring) 73 is formed. The Y-direction wiring (upper wiring) 73 is arranged so as to be insulated from the X-direction wiring (lower wiring) 72 by the interlayer insulating layer 16 and to be electrically connected to the element electrode 003. Although the Y-direction wiring (upper wiring) 73 is formed by two lines here, the present invention is not limited to this, and may be formed by a plurality of lines, and further, the X-direction wiring (lower wiring). ) 72, a plurality of wires may be similarly formed, and further, a plurality of wires in the X and Y directions may be formed. Next, as shown in FIG. 3E, a thin film of fine particles is formed on the entire surface or at a desired position. Then, patterning is performed by photolithography to form the conductive thin film 004 as shown in FIG. Further, a forming process and preferably an activating process are performed to form an electron source substrate. The forming process is a process of forming an electron emission portion by conducting a current-carrying process called a current-carrying forming process on the conductive thin film, and applying a pulse voltage or the like to both ends of the conductive thin film to locally destroy or deform the conductive thin film. Alternatively, it is to form an electron-emitting portion which is made to have a high electrical resistance by being altered. In the electron emitting portion, a crack is generated in a part of the conductive thin film, and electrons are emitted from the vicinity of the crack. The activation treatment refers to energization forming under an atmosphere containing a gas of an organic substance such as an aliphatic hydrocarbon, an aromatic hydrocarbon, an alcohol, an aldehyde, a ketone, an amine, a phenol, or an organic acid. Similarly, the application of pulses can be repeated. By performing the activation treatment, carbon or a carbon compound is deposited on the device, and the device current If and the emission current Ie are significantly changed.

The substrate 001 used in the present invention is
Examples thereof include quartz glass, glass having a reduced content of impurities such as Na, soda-lime glass, a glass substrate in which SiO ₂ is formed on soda-lime glass by sputtering or the like, and ceramics such as alumina. Element electrodes 002, 00
Any material may be used as the material of 3 as long as it has conductivity. For example, Ni, Cr, A
Metals or alloys such as u, Mo, W, Pt, Ti, Al, Cu, Pd, and Pd, Ag, Au, RuO ₂ , Pd
Metal or metal oxide and printed conductor composed of glass or the like, such as -ag, and semiconductor conductive materials such as polysilicon, and semiconductor materials such as polysilicon, and an In ₂ O ₃ -
Examples thereof include transparent conductors such as SnO ₂ .

The conductive pastes for forming the X-direction wiring and the Y-direction wiring are Pd, Ag, Au, RuO ₂ ,
A printing paste comprising a metal or metal oxide such as Pd-Ag, frit glass, a polymer as a binder and a suitable solvent.

As a material for the interlayer insulating layer 16, a general glass paste can be used. Conductive thin film 004
Pt, Ru, A can be given as specific examples of the materials constituting
g, Au, Ti, In, Cu, Cr, Fe, Zn, S
n, Ta, W, Pd and other metals, PdO, SnO ₂ , In ₂
O _3, PbO, oxides such as _{Sb 2 O 3, HfB 2,} Zr
_{B 2, LaB 6, CeB 6} , YB 4, GdB 4 , etc. borides, TiC, ZrC, HfC, TaC , SiC, and WC, etc., TiN, ZrN, nitrides such as HfN, Si,
Semiconductors such as Ge, carbon, AgMg, NiCu, P
b, Sn, etc., and is composed of a fine particle film. Note that the fine particles described here are a film in which a plurality of fine particles are aggregated, and as a fine structure, not only a state in which the fine particles are individually dispersed and arranged but also a state in which the fine particles are adjacent to each other or overlap each other (including an island shape) ) Membrane.

The electron source substrate of the image forming apparatus of the present invention is manufactured through the above steps. If there is a short-circuit defect between the wirings of the electron source substrate manufactured in this way, X
Between the direction wiring and the Y direction wiring, for example, 0.1 to 1.0 A,
Preferably, a short current can be completely broken by passing a large current of 0.3 to 0.5 A. At this time, only one divided line is broken, so that the remaining lines can send signals as usual.

Thereafter, the electron source substrate is fixed on a rear plate 81 as shown in FIG. 4, and then a face plate 86 (a fluorescent film 84 and a metal back 85 are formed on the inner surface of a glass substrate 83). ) Is disposed via the support frame 82, and the frit glass is applied to the joint portion of the face plate 86, the support frame 82, and the rear plate 81, and the frit glass is baked to seal the frit glass, whereby the image forming apparatus can be manufactured. 1 × 10 ⁻⁵ to 1 × 1 in the envelope constituted by the face plate 86, the support frame 82 and the rear plate 81.
The degree of vacuum of about 0 ^-7 torr is maintained, and the electrons emitted from the electron-emitting device are accelerated by the high voltage of several kV applied to the metal back (accelerating electrode) and collide with the fluorescent film to emit light. Occurs.

The wiring board of the present invention can be manufactured in the same manner as the electron source board of the image forming apparatus. As the substrate material used for the wiring substrate, quartz glass, glass having a reduced content of impurities such as Na, soda-lime glass, or Si formed on the soda-lime glass by sputtering or the like, as described above.
Examples thereof include a glass substrate on which O ₂ is laminated, a ceramic such as alumina, and the like. Moreover, the above-mentioned materials can be used as the wiring material, the interlayer insulating material, and the like. This wiring board can be widely used as a circuit board (printed board).

[0020]

【Example】

[Embodiment 1] A first embodiment of the present invention formed by using surface conduction electron-emitting devices and matrix wiring will be described with reference to FIGS. 1, 2 and 4. In FIG. 1, reference numeral 001 is a substrate made of soda-lime glass, and element electrodes 002 and 003 were formed by printing and firing an organic metal paste. Material is 100
It is composed of an Au thin film of 0 angstrom, and has an electrode interval of 20 μm and an electrode width of 300 μm in the central portion.

The X-direction wiring (lower wiring) 72 is 480 after printing Ag paste ink (4028A manufactured by Noritake Co., Ltd.).
Printed wiring obtained by firing at around ℃, thickness about 13μ
m and width 120 μm. This X-direction wiring (lower wiring) 7
2 is connected to the device electrode 002. 76 is an insulator formed by printing a paste containing glass as a main component (Noritake Co., Ltd. 7723B) and firing it at about 480 ° C., and is formed so as to cover the intersection with the Y-direction wiring (upper wiring). Has been done. Thickness about 15μm, width 300μm, length 40
It was set to 0 μm. Reference numeral 73 denotes two Y-direction wirings (upper wirings) according to the present invention. These are printed wirings obtained by printing Ag paste ink (4028A manufactured by Noritake Co., Ltd.) and firing at about 480 ° C., and intersect with the X-direction wiring (lower wiring) 72 above the interlayer insulating layer 76. , Element electrode 00
3 is connected. Each thickness is about 10μm, width 90μm,
The spacing was 50 μm. Note that these two Y-direction wirings (upper wirings) may have partial contact points.

Reference numeral 004 denotes a conductive thin film, which is a thin film made of PdO particles having a thickness of about 200 Å obtained by coating and baking an organic metal solution of Pd (CCP4230 manufactured by Okuno Chemical Industries Co., Ltd.). After coating and forming a film on the entire surface, patterning was performed by photolithography to form at positions on the device electrodes 002 and 003 as shown in FIG. The electron source substrate 71 of this embodiment has a size of 40 cm square, the electron-emitting devices 74 have an element array pitch of 1 mm, and the number of elements is 36.
They were arranged in a matrix of 0 × 360. Even if 10 such electron source substrates were produced and the short-circuited portion of the XY wiring crossing portion was repaired by the energization method, the disconnection defect did not occur.

After the fabrication as described above, the face plate 86 is formed on the electron source substrate 71 as shown in FIG.
They were opposed at a distance of mm. A blue plate glass was used as the substrate of the face plate 86. The fluorescent film 84 is color-coded into red (R), green (G), and blue (B).
Coating the substrate with a slurry in which a phosphor is mixed with a photosensitive resin,
It was dried and patterned by photolithography. The metal back 85 was formed by performing filming on the fluorescent film, forming an Al thin film having a thickness of about 300 angstrom by vacuum deposition, and then burning the film layer to burn it off.

After arranging the above in a vacuum envelope, a voltage is applied to the X-direction wiring (lower wiring) 72 and the Y-direction wiring (upper wiring) 73 to form a conductive thin film between the device electrodes 002 and 003.
04 was energized to obtain a crack-shaped electron emitting portion 005. Thereafter, an electron extraction voltage of 5 kV is applied using the metal back 85 as an anode electrode, and the XY wiring electrodes 72, 7 are formed.
3 through the device electrodes 002 and 003 to the electron emission portion 00.
When a voltage of 14 V was applied to 5, electrons were emitted. By irradiating the phosphor with the emitted electrons and adjusting the amount of the emitted electrons, the phosphor was made to emit light at an arbitrary intensity and an image could be displayed.

[Embodiment 2] Another embodiment of the present invention will be described with reference to FIG. When forming the Y-direction wiring (upper wiring) 73 in the first embodiment, only the Y-direction wiring (upper wiring) on the interlayer insulating layer 16 at the intersection with the X-direction wiring (lower wiring) 72 in which a short circuit may occur. 73 is divided into two to form a dividing unit 77. By using such a structure, it is possible to obtain the same effect as that of the first embodiment,
Furthermore, it is possible to further reduce the resistance of the upper wiring.

[Embodiment 3] An example in which the present invention is applied to a wiring board (printed board, circuit board) will be described below with reference to FIG. The X-direction wiring (lower wiring) 72 is a printed wiring obtained by baking Ag paste ink (4028A manufactured by Noritake Co., Ltd.) after firing at about 480 ° C., and has a thickness of about 13 μm and a width of 120 μm (see FIG. a)). 76 is an insulator formed by printing a paste containing glass as a main component (Noritake Co., Ltd. 7723B) and firing it at about 480 ° C., and is formed so as to cover the intersection with the Y-direction wiring (upper wiring). Has been done. Thickness about 15μm, width 300μm, length 400
μm (FIG. 5 (b)). Reference numeral 73 denotes two Y-direction wirings (upper wirings) according to the present invention. These are 480 after printing Ag paste ink (4028A manufactured by Noritake Co., Ltd.)
It is a printed wiring obtained by baking at around ℃,
The X direction wiring (lower wiring) 72 intersects at the upper part of 6. The thickness was about 10 μm, the width was 90 μm, and the interval was 50 μm.
Note that these two Y-direction wirings (upper wirings) may have partial contact points (FIG. 5C). A printed circuit board was created through the above steps. Even if 10 such prints were produced and the short-circuited portion at the XY wiring crossing portion was repaired by the energization method, no disconnection defect occurred.

[0027]

According to the present invention, even if a short-circuit defect occurs at the intersection of wirings, the short-circuit defect can be easily repaired by conducting repair and can be manufactured inexpensively with a high yield without increasing the number of steps. An image forming apparatus, a wiring board, and a manufacturing method thereof can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an electron source substrate of an image forming apparatus of the present invention.

FIG. 2 is a diagram showing an example of a manufacturing process of an electron source substrate of the image forming apparatus of the present invention.

FIG. 3 is a diagram showing an example of an electron source substrate of the image forming apparatus of the present invention.

FIG. 4 is a schematic view showing an example of a display panel of the image forming apparatus of the present invention.

FIG. 5 is a diagram showing an example of a manufacturing process of the wiring board of the present invention.

[Explanation of symbols]

 001 substrate 002, 003 element electrode 004 conductive thin film 005 electron emission part 71 electron source substrate 72 X-direction wiring (lower wiring) 73 Y-direction wiring (upper wiring) 74 surface conduction electron-emitting device 75 connection wire 76 interlayer insulation layer 81 rear Plate 82 Support Frame 83 Glass Substrate 84 Fluorescent Film 85 Metal Back 86 Face Plate 88 Envelope

Claims (7)

[Claims] 1. A wiring board having a plurality of intersecting wirings made of a thick film, wherein the intersecting portions between the wirings are insulated by an interlayer insulating layer, and the intersecting wirings are plural at least at the intersecting portions. A wiring board characterized by being divided. 2. The wiring (upper wiring) formed on the interlayer insulating layer among the intersecting wirings is divided into a plurality of wirings at least at the intersecting portions.
The wiring board as described. 3. A plurality of electron-emitting devices, each of which is composed of an electron-emitting portion and a pair of device electrodes, arranged in a matrix, and a plurality of thick films connected to the device electrodes for driving the electron-emitting devices. In an image forming apparatus using an electron source substrate, a wiring (lower wiring) and a plurality of Y-direction wirings (upper wirings) are insulated by an interlayer insulating layer at intersections of the wirings. An image forming apparatus, wherein at least one of the Y-direction wiring is divided into a plurality of lines at least at the intersection. 4. The image forming apparatus according to claim 3, wherein only the Y-direction wiring (upper wiring) is divided into a plurality of lines at least at the intersection. 5. The electron-emitting device is a surface conduction electron-emitting device, and a phosphor and an accelerating electrode are arranged on a substrate (face plate) facing an electron source substrate having the device, and these are vacuum. The image forming apparatus according to claim 3, which is held inside. 6. A method for manufacturing a wiring board, comprising: a plurality of intersecting wirings made of a thick film, wherein the intersecting portions between the wirings are insulated by an interlayer insulating layer, wherein at least one of the intersecting wirings is At least the crossing portion is formed by dividing into a plurality of lines, and when there is a short circuit between wirings at the crossing portion, a large current is caused to flow between two wirings intersecting at the shorting portion to repair the short circuit. And a method for manufacturing a wiring board. 7. A plurality of electron-emitting devices, each of which is composed of an electron-emitting portion and a pair of device electrodes, arranged in a matrix, and a plurality of thick films connected to the device electrodes for driving the electron-emitting devices. A method of manufacturing an image forming apparatus using an electron source substrate, wherein a wiring (lower wiring) and a plurality of Y-direction wirings (upper wiring) are formed by being insulated by an interlayer insulating layer at intersections of the wirings, At least one of the X-direction wiring and the Y-direction wiring is divided into a plurality of lines at least at the intersecting portion, and when there is a short circuit between the wirings at the intersecting portion, two wirings intersect at the shorted portion. A method of manufacturing an image forming apparatus, characterized in that a large current is passed between the electrodes to repair the short circuit.