JPH1125853A - Repairing method for silver electrode of plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the repairing method of a silver electrode of a plasma display panel capable of accommodating various sizes of short circuit defects and increasing the working state at a beam spot end part. SOLUTION: When a short circuit defect 2 of a silver electrode 1 formed on a glass substrate 9 of a plasma display panel is removed with laser beams, the laser beams are narrowed down in a fine spot 6, the fine spot 6 is scanned in two axial directions on the glass substrate 9 so as to remove the short circuit defect 2. The method is capable of accommodating various sizes of short circuit defects and improving the working state at a beam spot end part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a silver electrode formed on a glass substrate of a plasma display panel by using a laser beam to remove a short defect portion of the silver electrode.

[0002]

2. Description of the Related Art Plasma display panels (hereinafter referred to as P
It is called DP. ) Is a dot matrix type display panel using light emission of plasma discharge. In recent years, high-density and high-precision electronic components have been required, and high-precision repair technology has become necessary. Particularly, in a field where one defect is not allowed, such as a PDP, a laser beam is used. The method of repair using is increasingly important. On the other hand, with respect to the laser light source itself, a small and high-performance LD pump laser having a transmitter capable of supplying a stable and efficient laser beam has been developed. is there.

Generally, a laser beam having a short pulse width and a high peak output is used for repair processing. this is,
This is for almost eliminating the thermal influence on the periphery of the laser irradiation part.
Incidentally, silver, which is the material of the silver electrode of the PDP and which is to be repaired, has a light absorption rate slightly larger for far ultraviolet light, but smaller in the visible light and infrared light regions,
In addition, it has high thermal conductivity and a physical property that its melting point is lower than that of other metals, so that it is particularly susceptible to heat.

As a method of forming a silver electrode of a PDP, a method of patterning a silver paste into a glass substrate by a printing method or the like and then firing at 500 ° C. is common. During this firing, all the solvent contained in the silver in the form of paste evaporates.

The silver electrode thus formed has a thickness of about 6 μm, and it is generally difficult to perform repair processing using laser light.

Hereinafter, a conventional processing method will be described with reference to FIGS. 7 and 8. FIG. 7A shows a plan view of a conventional laser processing area, and FIG. 7B shows a processing sectional view thereof. In FIG. 7A, the laser beam has a spot area 60 as indicated by a hatched portion, and a short defect portion 62 between two silver electrodes 61.
For one shot, removal processing is performed. When the short defect portion 62 is larger than the spot area 60,
By removing the short area 62 by shifting the spot area 60 and overlapping shots. If the silver paste is too thick to be removed in one shot, the same portion is again irradiated with a laser and the removal process is repeated.

[0007] In FIG. 7B, reference numeral 63 denotes a glass substrate, and 65 denotes a laser beam.

[0008] The short defect portion 62 shown in FIG.
Silver swells, and the edge is dripped.

FIG. 8 shows a processing optical system used in a conventional PDP silver electrode repair method (hereinafter referred to as a conventional method). As shown in FIG. 8, in the conventional method, a short pulse laser light source 66 such as YAG is used, and a laser beam 65 transmitted through a slit mask 68 via an imaging optical system 67 is applied to a glass substrate 63 by a lens 69. By forming an image on the short defect portion 62, the short defect portion 62 is removed. The operator operates the laser observation optical system 7.
With 0, the removed portion can be observed.

[0010]

In the above-mentioned conventional configuration,
By changing the slit width of the slit mask 68 with respect to the size of the short defect portion 62, the size of the spot area 60 of the laser beam 65 can be changed.
Large defects, or vice versa, cannot be completely addressed.

The spot area 60 of the laser beam 65
Is large, the energy density is different between the end and the center. Therefore, when laser processing is performed in one shot, the energy density is low at the end of the spot area 60,
It is easy to form a molten state of the silver electrode. Therefore, in this case, swelling of silver or the like is observed around the defect correction portion, and there is a possibility that insulation failure may occur after the product is completed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its main purpose is to be able to cope with short defects of various sizes and to improve the processing condition at the end of the spot area. And a method for repairing a silver electrode of a plasma display panel.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a plasma display panel having a silver electrode formed on a glass substrate of a plasma display panel. In the electrode repair method, the laser beam is narrowed to form a spot beam, and the spot beam is biaxially scanned on the glass substrate to remove the short defect portion. .

In such a method, the laser beam is narrowed down to a spot beam, and the spot beam is scanned in a biaxial direction on the glass substrate to remove the short-circuit defect. The removal processing can be performed in a dense area from a large area to a large area. Further, since the beam spot is made small, there is almost no portion in the spot where the energy density is low. Therefore, silver is evaporated and removed without melting, and processing can be performed without causing silver dripping at the boundary of the removed region.

More specifically, the short defect portion is approximately recognized as a rectangular shape, and the recognized rectangular shape is used as the spot beam scanning area, or the glass substrate and / or the glass substrate.
By moving the spot beam itself, scanning of the spot beam on the glass substrate in the biaxial directions may be performed.

Further, after the removal processing of the short defect portion, the removal processing area is cleaned by irradiating a laser beam having a reduced energy density to the cleaning processing area.
Since fine scattered matter generated by the processing for removing the short defect portion can be selectively removed, the processing state can be further improved.

As a result, it is possible to obtain a silver electrode repair method for a plasma display panel capable of coping with short defects having various sizes and improving a processing state at an end of a beam spot.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The following embodiments are examples in which the present invention is embodied, and do not limit the technical scope of the present invention.

FIG. 1 is a flowchart showing a schematic procedure of a silver electrode repair method for a plasma display panel according to the present embodiment. In FIG. 1, in the silver electrode repairing method for a plasma display panel according to the present embodiment (hereinafter, referred to as the present method), first, a laser beam is narrowed down to a spot beam (step S1). Next, the plasma display panel to be repaired (hereinafter referred to as P
It is called DP. The operator recognizes the short-circuit defect of the silver electrode in step (2) (step S2). Then, based on the recognition result, the operator sets a spot beam scanning area (step S3). More specifically, as shown in FIG. 2A, an operator recognizes a short defect 2 extending from the silver electrode 1, and scans the points 3 and 4 for setting the scanning area so as to cover the short defect 2. Two points are designated, and the scanning area 5 is set in a rectangular shape as indicated by a hatched portion having the two points as diagonals.

Next, the spot beam is scanned in the two axial directions in the scanning region 5 to remove the short defect portion 2 (step S4). FIG. 3A shows an example of a scanning procedure for removing the short defect 2 by using one minute spot 6 which is a spot area of the spot beam. In the figure, the minute spot 6 is the silver electrode 1
While moving back and forth in the longitudinal direction (the direction of the arrow in the figure), the micro spots 6 are sequentially moved to the micro spot 7 and the micro spot 8 sequentially by a predetermined pitch in the direction perpendicular to the longitudinal direction. FIG. 3B shows a state after the short defect portion 2 has been scanned by the minute spot 6. In the figure, the removal area is a minute spot 6
Are all filled with the machining trajectory. FIG. 3 (C)
Shows a cross section of the glass substrate 9 after scanning of the minute spot. Here, the short defect portion 2 extending from the silver electrode 1 to the adjacent electrode in FIG. 3A is the short defect portion seen in the center of FIG. The laser repair mark 10 is formed by digging the glass substrate 9 slightly. The laser repair mark 10 has less sag at the edge portion 11 of the silver electrode 1 as compared with the conventional example. However, after the short defect is removed by the laser, fine scattered matter 12 may be scattered in and around the removed area.

In such a case, a cleaning process for removing the fine flying substances is performed subsequently (steps S5 and S6). FIG. 2B shows a state after the short defect has been removed by scanning with a minute spot. As shown in the figure, the scattered matter 12 is generally spread. In order to remove the flying objects 12, the scanning area 1 which has a larger area than the scanning area 5 is approximated to a scanning area 1 having a rectangular shape having two points 13 and 14 for setting the scanning area.
Set 5. FIG. 2C shows traces of defect removal (scanning region 5) and laser cleaning (scanning region 15), respectively, in a state where there is no scattered matter.

FIG. 4 is an explanatory diagram of laser cleaning. 4A shows a cross-sectional view after the short defect portion 2 is removed by scanning with a minute spot. In the figure, fine scattered matter 12 is also seen on the silver electrode 1 and the glass substrate 9 by removing the minute spot by scanning.

FIG. 4B shows a state where the laser beam 16 is performing a cleaning scan. In the figure, when the laser beam 16 is reciprocally scanned and moved to the state of the laser beam 16a, the trace 17 for removing the short defect and the fine scattered matter on the silver electrode 1 are removed.

At this time, the scanning process is performed with the energy density per unit area lowered by weakening the output of a laser light source (not shown) (FIG. 1, step S5). In addition, by irradiating a wide area with a large defocus amount of a not-shown condenser lens, the energy density per unit area can be reduced and scanning can be performed. At this time, the energy density at the processing point of the laser is set so as not to damage the underlying structure.

FIG. 5 shows a laser optical system of an apparatus applicable to the present method. In FIG. 5, reference numeral 18 denotes a short pulse laser light source such as YAG, 19 denotes an observation light source, 20 denotes an observation light source fiber, 21 and 22 denote dichroic mirrors,
23, a CCD camera for an observation optical system; 24, an objective lens; 25, a revolver; 26, a laser beam to be condensed; As in the above, reference numeral 1 denotes a silver electrode, 9 denotes a glass substrate, and 2 denotes a short defect portion.

In this laser optical system, as shown in FIG. 5, the operator observes the short defect portion 2 with the CCD camera 23. Here, since the laser optical axis and the axis of the observation optical system are aligned, the CCD camera Each scanning area can be determined while looking at 23. Each scanning area can be set by the method shown in FIGS. 2A and 2B, respectively.

Further, by rotating the revolver 25, the magnification of the objective lens 24 can be changed. Thus, at the time of repair, if the processing is performed with the up focus, the processing can be performed with less damage to the glass substrate 9.

FIG. 6 shows the appearance of the apparatus. As shown in the figure, the processing head 27 has a configuration in which the laser light source that generates the short pulse shown in FIG. 5 is combined with a laser optical system and an observation optical system. Specifically, the board setting unit 2
8, a processing head 27, and this processing head 27
It has a mechanism for moving in the Y and Z axis directions. In the drawing, the processing head 27 can be moved by the Z-axis moving mechanism 29 to adjust the focus at the time of repair.
The short-circuit defect of the silver electrode of the glass substrate set in the substrate setting unit 28 is read by the observation optical system of the processing head 27, and the glass substrate is coarsely processed by the X-axis moving mechanism 30 and the Y-axis moving mechanism 31, respectively. Position, and then the X-axis moving mechanism 30 and the Y-axis moving mechanism 31
To perform a reciprocating motion.

In the above-described embodiment (method), the laser beam is narrowed down to form a spot beam (step S1 in FIG. 1), and then the scanning area of the minute spot is set (steps S2 and S3 in FIG. 1). The reverse procedure may be adopted. In steps S2 and S3, the operator recognizes the short defect and sets the scanning area of the minute spot based on the recognition result. However, a part or all of these series of operations is performed. May be automated.

In the above embodiment (method), after the removal processing of the short defect portion (steps S1 to S3 in FIG. 1),
Cleaning process is performed (steps S5 and S6)
However, the cleaning process may be omitted depending on conditions, for example, when there is almost no flying matter after the process of removing the short defect portion.

In the above-described embodiment (method), each scanning area is set to a rectangular shape and a diagonal point is designated. However, the scanning area is set to a shape other than this, for example, a circular shape.
The center and radius may be indicated. Further, a completely different setting method, for example, a method of inputting coordinates to a control unit (not shown) may be used.

Further, in the above embodiment (apparatus), the glass substrate side is moved by the operation of the X-axis moving mechanism and the Y-axis moving mechanism in order to scan the short defect portion with a minute spot in two axial directions. Alternatively, the minute spot itself may be moved by the operation of the optical system. Alternatively, of course, the glass substrate side and the minute spot itself may be moved in the one axis direction, and the two may be moved in the two axis direction by a combination of the two.

Further, in the above embodiment (apparatus), the output of the laser light source is changed to emit a spot beam having a high energy density and a laser beam having a low energy density, but separate laser light sources having different outputs are used. May be provided. In this case, the processing for removing the short defect by scanning with the spot beam and the cleaning processing for scanning with the laser beam having a low energy density can be performed in parallel with a slight shift in the timing between the two. Can be shortened.

[0034]

As is apparent from the above description, according to the present invention, it is possible to perform removal processing in a dense area from a small area to a large area. Further, since the beam spot is made small, there is almost no portion in the spot where the energy density is low. Therefore, silver is evaporated and removed without melting, and processing can be performed without causing silver dripping at the boundary of the removed region.

Further, since fine scattered matter generated by the processing of removing the short defect portion can be selectively removed, the processing state can be further improved.

As a result, it is possible to obtain a silver electrode repair method for a plasma display panel capable of coping with short defects having various sizes and improving a processing state at an end of a beam spot.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a schematic procedure of a silver electrode repair method for a plasma display panel according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a processing area for removing a short defect portion and a laser cleaning area.

FIG. 3 is an explanatory diagram showing a laser irradiation part and a processing result at the time of repair by the present method.

FIG. 4 is an explanatory diagram showing a laser cleaning method.

FIG. 5 is a schematic diagram showing a schematic configuration of an optical system of an apparatus applicable to the present method.

FIG. 6 is a schematic diagram showing an overall configuration of an apparatus applicable to the present method.

FIG. 7 is an explanatory diagram showing a laser irradiation part and a processing result at the time of repair by a silver electrode repair method of a plasma display panel according to a conventional example.

FIG. 8 is a schematic diagram showing a schematic configuration of an optical system of an apparatus applicable to a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silver electrode 2 Short defect part 3, 4 Scan area setting point 5 Micro spot scanning area 6-8 Micro spot by spot beam 9 Glass substrate 10 Laser repair mark 11 Edge part 12 Scattered object 13, 14 Scan area setting point 15 Laser scanning area

Claims (4)

[Claims] 1. A silver electrode repair method for a plasma display panel, wherein a short defect portion of a silver electrode formed on a glass substrate of the plasma display panel is removed and processed by a laser beam. A method of repairing a silver electrode of a plasma display panel, wherein the short beam is removed by scanning the spot beam on the glass substrate in two axial directions. 2. The silver electrode repair method for a plasma display panel according to claim 1, wherein the short defect portion is approximately recognized as a rectangular shape, and the recognized rectangular shape is used as the spot beam scanning area. 3. The silver electrode repair of a plasma display panel according to claim 1, wherein scanning of the spot beam on the glass substrate in two axial directions is performed by moving the glass substrate and / or the spot beam itself. Method. 4. After the removal processing of the short defect portion,
The cleaning process is performed by irradiating the removal processing region with a laser beam having a reduced power density.
The method for repairing a silver electrode of a plasma display panel according to any one of the above items.