JP2001250480A - Device and method for inspecting plasma display panel rear plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection device and its method for the fluor formed on a rear plate of a plasma display panel minimizing excessive inspections and/or overlooked inspections and being able to properly specify the cause of a defect. SOLUTION: The inspection device for the rear plate of a plasma display panel is intended to inspect the RGB (red/green/blue) fluors formed on the rear plate of a plasma display panel and comprises photographing means for review equipped with ultraviolet ray radiation means and those for automatic inspection. The inspection method for the rear part of the plasma display panel specifies that the defect detected by the photographing means for automatic inspection using the above inspection apparatus is visually decided as to whether it is good or bad using the photographing means for review.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for inspecting a rear panel of a plasma display panel, and more particularly to an apparatus and method for inspecting a rear panel of a plasma display panel.
The present invention relates to an apparatus and a method capable of more accurately inspecting a GB phosphor.

[0002]

2. Description of the Related Art Normally, phosphors for R (red), G (green), and B (blue) are repeatedly applied on a back plate of a plasma display panel in the form of stripes. If there is a defect in the applied state of the body, the light emission state of the predetermined phosphor cannot be obtained, and a defect occurs in an image on the display panel. Therefore, the state of application of the phosphor is inspected at the stage of manufacturing the back plate of the plasma display panel.

[0003] The plasma display panel is a display device that irradiates a phosphor formed on a back plate with ultraviolet rays and performs display by emitting light from the phosphor. Irradiating the phosphor to emit light and visually inspecting the enlarged image is the most accurate inspection method.

However, the efficiency of visual inspection is low. For example, a technique described in Japanese Patent Application Laid-Open No. H11-16498 has been studied. Japanese Patent Application Laid-Open No. 11-164
Japanese Patent Publication No. 98 discloses an automatic inspection method in which an inspection is performed by irradiating ultraviolet rays while excluding ozone, and a predetermined inspection can be performed even in the atmosphere.

[0005]

However, the method disclosed in Japanese Patent Application Laid-Open No. 11-16498 has the following problems. Since there is no review imaging device having ultraviolet irradiation means and only automatic inspection, the overdetection rate and the oversight rate of defects are high. Further, in the case of only the automatic inspection, since the image of the defect cannot be visually confirmed, it is difficult to specify the type of the defect and the cause of the defect.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems in the prior art, and to provide an apparatus for inspecting a phosphor formed on a back panel of a plasma display panel, which is capable of accurately specifying the cause of occurrence of a defect with few overdetections and oversights. And to provide an inspection method.

[0007]

In order to solve the above-mentioned problems, an apparatus for inspecting a plasma display panel back plate according to the present invention is an apparatus for inspecting an RGB phosphor formed on a plasma display panel back plate. It is characterized by having review imaging means provided with ultraviolet irradiation means and automatic inspection imaging means. The review imaging means irradiates the defect with ultraviolet rays and emits a fluorescent material to visually determine the quality of the defect, so that the defect can be checked in a state close to the state in which the user uses the product. , Over-detection and inspection with few oversights become possible. In particular, even when the detection threshold value for the automatic inspection is set strictly in order to prevent oversight, it is possible to prevent overdetection by visual inspection. Therefore, it is possible to reduce product loss due to overdetection and complaints from the user due to oversight, and it is possible to reduce manufacturing costs.

In the apparatus for inspecting a rear panel of a plasma display panel according to the present invention, the ultraviolet irradiation means of the review imaging means may be configured to also serve as the illumination means of the automatic inspection imaging means.

Further, for example, a two-dimensional CCD camera can be used as a light receiving portion of the review imaging means, and a one-dimensional CCD camera can be used as a light receiving portion of the automatic inspection imaging means.

It is preferable that the field of view of the review imaging means and the field of view of the automatic inspection imaging means overlap. Further, it is preferable that the review imaging means has a focal length of 50 mm or more and is arranged so as not to block the visual field of the automatic inspection imaging means. The review imaging unit may further include a visible light illumination unit.

The automatic inspection imaging means has a θ axis adjustment mechanism as an angle adjustment mechanism around an axis perpendicular to the plasma display panel back plate, and a φ axis adjustment mechanism as an angle adjustment mechanism with respect to the perpendicular axis. Is preferred.

[0012] A method for inspecting a back panel of a plasma display panel according to the present invention uses the inspection apparatus as described above.
The defect detected by the automatic inspection image pickup means is visually judged to determine the quality using the review image pickup means.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 and FIG.
1 shows an inspection apparatus for a plasma display panel back plate according to an embodiment of the present invention. In the drawing, reference numeral 1 denotes a plasma display panel (hereinafter referred to as PD) to be subjected to inspection.
It may be abbreviated as P. ), And the PDP back plate 1 has R (red),
Phosphors 305, 306, and 307 for G (green) and B (blue)
Are repeatedly applied in stripes in order.

Plasma display panel back plate mechanism 3
00, as shown in FIG.
1, a dielectric layer 30 on which an address electrode 302 is disposed
3, RGB phosphors 305, 306, between partition walls 304,
PDP 307 is repeatedly applied in stripes in order
A back plate 1 is provided, a front glass substrate 308 is provided above the back plate 1, and a dielectric layer 310 having a display electrode 309 disposed between the back plate 1 and the front glass substrate 308 and a protective film 311 are provided. Is interposed. Plasma 312 is generated by the voltage between the display electrode 309 and the address electrode 302, and the phosphor at the selected position is colored, and a desired color display is performed by a combination of the colors of the phosphors. ing.

RGB phosphor 305 on PDP back plate 1
The coating of 306 and 307 is performed by screen printing, for example, as shown in FIG. 5, and the excess amount of the phosphor applied through the printing screen 402 is scraped off with a squeegee 401, thereby obtaining each of the phosphors as shown in FIG. Phosphor 30
5, 306 and 307 are applied between the partition walls 304 in a predetermined amount.

However, the RGB phosphors 305, 306,
If the coating of 307 is not performed in a predetermined manner, for example, color unevenness as shown in FIG. 6 may be generated, and for example, reddish color unevenness 501 and bluish color unevenness 502 are generated. In addition, as shown in FIG.
In the arrangement of 5, 306, and 307, a portion 60 in which a phosphor of a certain color protrudes into a phosphor portion of the next color to cause color mixture.
In some cases, there may be a portion where a dark spot 602 occurs due to a coating defect or a coating omission.

RGB phosphor 305 on PDP back plate 1
Various defects as described above in the application of 306 and 307 are inspected by the inspection apparatus shown in FIG. Figure 1 again
The PDP back plate 1 is transported by a transport device 2 having transport rollers and the like, and the transport device 2 is controlled by a drive control device 4.

Above the transfer device 2, an XY gantry stage 3, an ultraviolet irradiation device 5, an automatic inspection imaging device 7, and a review imaging device 8 as shown in FIG. UV irradiation device 5, automatic inspection imaging device 7,
The review imaging device 8 is fixed to one housing, and this housing is referred to as a measuring head 9. The measuring head 9 including the automatic inspection imaging device 7, the review imaging device 8, and the ultraviolet irradiation device 5 is mounted on the XY gantry stage 3 as shown in FIG. The XY gantry stage 3 is for scanning the measuring head 9 over the entire surface of the PDP back plate 1. The operations of the XY gantry stage 3 and the transfer device 2 are controlled by the drive control device 4.

The image pickup device 7 for automatic inspection includes the image processing device 1
0, and the review imaging device 8 is also connected to the image processing device 10. The control device 11 is connected to the drive control device 4, the lighting control device 6 for controlling lighting of the ultraviolet irradiation device, and the image processing device 10, and controls the operation of these devices. The image processing device 10 includes a display device 12
Is connected, and the display device 12 is connected to the image processing device 10.
Can display the defect information detected by.

The ultraviolet irradiation device 5 is for exciting and emitting light from the phosphor applied on the PDP back plate 1, and irradiates the PDP back plate 1 with ultraviolet rays. As an ultraviolet light source,
An excimer lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultraviolet laser, or the like can be selected, but an excimer lamp having a wavelength of 222 nm is preferable because ozone is less generated and the RGB phosphor emits light in a well-balanced manner. Further, it is preferable to transmit the ultraviolet ray using an optical fiber such as quartz glass because the configuration of the measuring head can be simplified, the attenuation in the air is small, and the amount of generated ozone is small. In the case of performing an inspection by irradiating a fluorescent substance with ultraviolet light as an automatic inspection, for example, as shown in FIG. It is preferable to irradiate the visual field range of the imaging device 8 with ultraviolet rays because the configuration is simplified and the cost is reduced.
In the embodiment shown in FIG. 8, the review imaging device 8 includes a visible light illumination device 21.

The automatic inspection image pickup device 7 includes a PDP back plate 1.
The upper range is divided into pixels, the luminance of each pixel is measured, converted into an image signal, and transmitted to the image processing device 10. A one-dimensional or two-dimensional CCD or imaging tube can be selected as the light receiving unit of the automatic inspection imaging device 7. However, when a one-dimensional CCD camera is used, inspection can be performed at high speed. Further, if a TDI camera is used, inspection can be performed with high sensitivity even when the illumination is weak. When ultraviolet light is used as the illumination of the automatic inspection imaging device 7, it is preferable to use a color line sensor camera because each image of the RGB phosphor can be obtained by one camera and the optical system can be simplified. The type of illumination of the image pickup device 7 for automatic inspection is not limited to ultraviolet rays, and if a diagonal direction is illuminated using visible light, it is possible to detect a coating defect of the phosphor with unevenness on the surface. .

The review imaging device 8 is for visually judging a defect detected by the automatic inspection. The review imaging device 8 converts the emitted luminance of a certain range on the PDP back plate 1 into a video signal by the ultraviolet light emitted from the ultraviolet irradiation device 5. The converted video signal is temporarily stored in the memory by the image processing device 10 and then transmitted to the display device 12. From the image displayed on the display device 12, the quality is visually judged. Therefore, according to the present invention, the defect is irradiated with ultraviolet rays, the phosphor is emitted, and the quality is visually determined, so that the state of the defect can be confirmed in a state close to the state in which the user uses the product. And high-precision inspection becomes possible.

It is preferable to use a two-dimensional CCD camera as the light receiving portion, since an image can be obtained without scanning the measuring head 9 during review. Furthermore, two-dimensional color CCD
Using a camera is good because it can identify which color phosphor is defective. Further, a device having an automatic gain adjustment function (AGC function) is preferable.

As the optical system portion, one having a focal length of 50 mm or more is preferable because it can be arranged so as not to obstruct the visual field of the image pickup device 7 for automatic inspection. The optical magnification is 0.5
It is preferably from 5 to 5 times. Furthermore, it is more preferable to use a zoom lens because defects of any size can be determined.

In order to perform a review based on the result of the automatic inspection, it is necessary to perform an operation for obtaining an accurate positional relationship between the imaging device for review 8 and the imaging device for automatic inspection 7. However,
In mechanical precision, errors may occur in units of millimeters due to the fitting of screw holes and the like. Therefore, a certain reference point is captured by both imaging and imaging devices, and a positional relationship is obtained from coordinates on the image, coordinates of the XY gantry stage 3, and the like. And the working time is long.

Therefore, as shown in FIG. 8, if the field of view of the review imaging device 8 is arranged so as to overlap with the field of view of the automatic inspection imaging device 7, the same reference point can be used for both the imaging devices. , An accurate positional relationship can be obtained in pixel resolution units of the imaging device, and the operation is completed in a short time. In addition, when the review imaging device 8 has the illuminating means 21 for visible light, it is possible to use other than the phosphor as the reference point, and the worker is not exposed to ultraviolet rays. Therefore, the operation can be performed easily and safely, which is more preferable. Further, when the imaging device 7 for automatic inspection is a one-dimensional camera, as shown in FIG. 9, an adjustment mechanism for an angle with respect to an axis perpendicular to the plasma display panel back plate (in the illustrated example, with respect to the mounting surface 22). When a certain φ-axis adjusting device 23 is provided, the visual field range of the review imaging device 8 and the visual field range of the automatic inspection imaging device 7 can be overlapped by a simple adjustment.

The image processing device 10 is for detecting a defect generated in the fluorescent material, receives image signals of each of the RGB fluorescent materials imaged by the image pickup device 7 for automatic inspection, and uses a known image processing technology. Image analysis is performed to detect defects.

In the case of performing difference processing between pixels separated by a certain interval as image processing, the stripe direction of the phosphor is set to either the X or Y coordinate of the image processing apparatus in order to suppress the occurrence of a pseudo defect. Need to match. Therefore,
As shown in FIG. 10, an angle adjustment mechanism around an axis perpendicular to the plasma display panel back plate (the mounting surface 2 in the illustrated example).
In the case of having the θ-axis adjusting device 24 which is an angle adjusting mechanism for (2), it is possible to easily adjust the stripe direction of the phosphor.

The control device 11 controls the transfer device 2, the ultraviolet irradiation device 5, the imaging devices 7, 8,
The operation command is given to the image processing device 10, and the display device 12 displays each defect information detected by the image processing device 6.

In the present invention, the arrangement of RGB on the back plate of the plasma display panel is not limited to the parallel stripe arrangement as shown in FIG. For example, as shown in FIG. 11, AC type plasma display panel back plate 1 in which RGB are arranged in a matrix.
04.

FIG. 12 is a block diagram showing another embodiment of the present invention. The visual inspection is performed only when a defect occurs, and the inspection time is long. Therefore, if the visual inspection is directly installed in the production line, the visual inspection becomes a rule and the production efficiency is reduced. Therefore, FIG.
As shown in (1), even if a defect occurs by separating the visual inspection from the automatic inspection via the buffer, the production can be continued without reducing the efficiency. Further, the embodiment of the automatic inspection is not limited to the one shown in the above-described embodiment, and for example, as shown in FIG. 13, the imaging devices 32 are arranged in a line on the PDP back plate 31, and the imaging device 32 and the ultraviolet irradiation device 33 are provided. On the other hand, when the transport device 34 transports the PDP substrate 31, the inspection may be performed over the entire surface. As described above, the relative positions and arrangement of the imaging device, the ultraviolet irradiation device and the PDP back plate, and the arrangement of the imaging devices can be set substantially arbitrarily.

The operation of the inspection apparatus according to the present invention will be described with reference to the above-described embodiment. When the PDP back plate 1 is loaded into the transport device 2 from the upstream device, the transport device 2 sends a substrate loading signal to the control device 11. , And the conveyance of the PDP back plate 1 is started. When the PDP back plate 1 is transferred to a predetermined place, the transfer device 2 is moved by a back plate fixing device (not shown).
The DP back plate 1 is fixed, and a fixing completion signal is given to the control device 11. When the fixing completion signal is input, the control device 11 turns on the ultraviolet irradiation device 5 via the lighting control device 6. When the XY gantry stage 3 conveys the measuring head 9 to a predetermined imaging start position, the XY gantry stage 3 supplies a capture preparation completion signal to the control device 11. When the capture preparation completion signal is input, the control device 11 gives an image capture start signal to the XY gantry stage 3 and the image processing device 10. The XY gantry stage 3 to which the image capture start signal is given starts moving at a predetermined speed, stops after moving a predetermined distance, and then stops. The image processing apparatus 10 to which the image capturing start signal is given starts capturing the image signal output from the automatic inspection imaging apparatus 7. The image processing device 10 stores an image signal and detects a defect occurring in the PDP back plate 1 by a known image processing technique. Hereinafter, the control device 11 moves the XY gantry stage 3 so that the measuring head 9 can inspect the entire PDP back plate 1.
After the completion of the entire inspection, the control device 11 notifies the inspector of the completion of the automatic inspection by a lamp or the like.

The inspector who is ready for the visual inspection gives the controller 11 a review start signal. After receiving the review start signal, the control device 11 moves the measuring head for all the defect candidates detected by the automatic inspection based on the defect information, turns on the ultraviolet irradiation device 5, and then sends the review imaging device 8 Then, an image of the defective portion is picked up and displayed on the display device 12. The inspector visually inspects the defect candidate portion displayed on the display device 12 and determines pass / fail. After visually inspecting all the defect candidate portions, the inspector gives a visual inspection end signal to the control device 11. The control device 11 which has been given the visual inspection end signal gives the PDP back plate discharge signal to the transport device 2. The transport device 2 to which the discharge signal is given unloads the PDP back plate 1 to the downstream device.

[0034]

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to this. Example 1 The ultraviolet irradiation device 5 used was an excimer lamp having a lighting frequency of 14.56 MHz and an irradiation ultraviolet center wavelength of 222 nm, in which Kr and Cr were sealed. Review imaging device 7
Uses a two-dimensional color CCD camera (XC-711RR) manufactured by Sony Corporation as a light receiving part, and uses a 0.75-4.5x zoom lens (ML-ML-M manufactured by Moritex Corporation) as an optical system part.
Z07545DM) was used. As a visible light illumination device, a halogen light source (MHF-D1) manufactured by Moritex Corporation is used.
00LR) was used. The image pickup device 8 for automatic inspection is NE
The lens was selected such that one pixel corresponds to 30 μm on the PDP back plate using a three-panel color line sensor camera (3CL2048B) manufactured by Company D with 2048 pixels.
The PDP back plate 1 uses a substrate containing a print defect and color unevenness.
It was conveyed at 5 m / min and an automatic inspection was performed. After the completion of the automatic inspection, a visual inspection was performed on the detected defect candidate portion using the review imaging device 7. As a result, RGB
Printing defects and color unevenness of each phosphor were detected with high accuracy.

[0035]

As described above, according to the apparatus and method for inspecting a plasma display panel back panel according to the present invention, the following various effects can be obtained. (1) The defect is irradiated with ultraviolet rays, the phosphor is emitted, and the quality is visually determined. Therefore, the defect state can be confirmed in a state close to the state where the user uses the product. Inspection with few oversights is possible. Therefore, it is possible to reduce product loss due to overdetection and complaints from users due to oversight, and it is possible to keep manufacturing costs low. (2) Since there is no need to separately prepare ultraviolet irradiation means,
Inspection costs can be kept low. (3) Automatic inspection can be performed at high speed, and review can be performed easily without moving the stage. (4) The positional relationship between the review imaging means and the automatic inspection imaging means can be obtained accurately and in a short time. (5) Since the field of view of the image pickup means for automatic inspection is not obstructed, the inspection width can be made long and the inspection time can be shortened. (6) When determining the positional relationship between the review imaging means and the automatic inspection imaging means, it is not necessary to use ultraviolet rays, so that the work can be easily performed without the need for protective equipment. (7) The direction of formation of the phosphor layer and the direction of the line sensor camera element, and the positional relationship between the visual field of the review imaging means and the visual field of the automatic inspection imaging means can be easily adjusted. (8) Since the defect candidate point is detected by the automatic inspection and the pass / fail judgment is made visually, the inspection can be performed at high speed and with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for inspecting a back panel of a plasma display panel according to an embodiment of the present invention.

FIG. 2 is a perspective view around an XY gantry stage of the apparatus of FIG. 1;

FIG. 3 is a schematic plan view of a plasma display panel back plate.

FIG. 4 is a partial longitudinal sectional view of the plasma display panel.

FIG. 5 is a perspective view illustrating a method for printing a phosphor on a back plate by a printing machine.

FIG. 6 is a diagram illustrating an example of various print defects detected in a print inspection process.

FIG. 7 is a diagram illustrating another example of various printing defects detected in a print inspection process.

FIG. 8 is a schematic configuration diagram illustrating a relationship among arrangements of an imaging device for automatic inspection, an imaging device for review, and an ultraviolet irradiation device.

FIG. 9 is a schematic side view showing a φ-axis adjustment mechanism.

FIG. 10 is a schematic plan view showing a θ-axis adjusting mechanism.

FIG. 11 is a schematic plan view showing another example of the back plate of the plasma display panel.

FIG. 12 is a block diagram showing another embodiment of the present invention.

FIG. 13 is a schematic perspective view showing another embodiment of the automatic inspection according to the present invention.

[Explanation of symbols]

 1, 31, 104 Plasma display panel back plate 2, 34 Transport device 3 XY gantry stage 4 Drive control device 5, 33 Ultraviolet irradiation device 6 Lighting control device 7 Automatic inspection imaging device 8 Review imaging device 9 Measurement head 10 Image processing Device 11 Control device 12 Display device 21 Visible light illumination device 22 Mounting surface 23 φ axis adjustment device 24 θ axis adjustment device 33 Imaging device 300 Plasma display panel back plate mechanism 301 Back glass substrate 302 Address electrode 303 Dielectric layer 304 Partition wall 305 Fluorescence Body (R color) 306 Phosphor (G color) 307 Phosphor (B color) 308 Front glass substrate 309 Display electrode 310 Dielectric layer 311 Protective film 312 Plasma 401 Squeegee 402 Printing screen 501 Uneven color (reddish portion) 502 Color shading (blue) Portion) 601 mixed color portion 602 scotoma

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Osamu Kuramata 1-1-1, Sonoyama, Otsu-shi, Shiga F-term in the Toga Company's Shiga Plant (reference) 5C012 AA09 5C040 GG09 JA26 JA31 MA24 MA26 5G435 AA00 AA17 BB06 EE33 KK05 KK10

Claims (8)

[Claims] 1. An inspection apparatus for an RGB phosphor formed on a back plate of a plasma display panel, comprising: an imaging unit for review provided with an ultraviolet irradiation unit; and an imaging unit for automatic inspection. Inspection device for plasma display panel back plate. 2. The apparatus for inspecting a back panel of a plasma display panel according to claim 1, wherein said ultraviolet irradiation means also serves as an illumination means of an image pickup means for automatic inspection. 3. The light receiving section of the review imaging means is a two-dimensional C
3. The apparatus for inspecting a rear panel of a plasma display panel according to claim 1, wherein the apparatus is a CD camera, and a light receiving unit of the image pickup unit for automatic inspection is a one-dimensional CCD camera. 4. The inspection of the back panel of the plasma display panel according to claim 1, wherein the field of view of the review imaging unit and the field of view of the automatic inspection imaging unit overlap each other. apparatus. 5. The review imaging means has a focal length of 50 mm or more, and is arranged so as not to block the visual field of the automatic inspection imaging means. The inspection device for a back panel of a plasma display panel according to any one of the above. 6. The review imaging means further comprises an illuminating means for visible light.
The inspection device for a back panel of a plasma display panel according to any one of the above. 7. The automatic inspection imaging means includes a θ axis adjustment mechanism that is an angle adjustment mechanism about an axis perpendicular to the plasma display panel back plate, and a φ axis adjustment mechanism that is an angle adjustment mechanism with respect to the vertical axis. The plasma display panel back panel inspection apparatus according to any one of claims 1 to 6, further comprising: 8. An inspection apparatus according to claim 1, wherein the defect detected by the automatic inspection imaging means is visually judged for pass / fail using the review imaging means. Inspection method for plasma display panel back plate.