JP4531186B2 - Plasma display panel back plate inspection apparatus and manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma display panel (hereinafter, also abbreviated as PDP) back plate inspection apparatus and manufacturing method, and more particularly, it is possible to more accurately inspect RGB phosphors formed on a plasma display panel back plate. The present invention relates to an inspection apparatus and a manufacturing method.
[0002]
[Prior art]
Usually, phosphors for R (red), G (green), and B (blue) are repeatedly applied in order in the form of stripes on the back plate of the plasma display panel. If there is a defect, the light emission state of a predetermined phosphor cannot be obtained, and the image on the display panel is defective. Therefore, the phosphor coating state is inspected at the manufacturing stage of the plasma display panel back plate.
[0003]
As a method for inspecting a plasma display panel back plate, for example, Japanese Patent Application Laid-Open No. 11-16498 discloses an inspection method in which an inspection by ultraviolet irradiation is performed while eliminating ozone, and a predetermined inspection can be performed even in the atmosphere. In the inspection method described in Japanese Patent Application Laid-Open No. 11-16498, a video image signal from an imaging unit is directly sent to an image processing device, and in order to process each RGB video signal, a memory is provided in the image processing device. Operations such as development on the top, use of a plurality of image processing apparatuses, and manual switching are required. Further, regarding the movement of the inspection object, this Japanese Patent Application Laid-Open No. 11-16498 is briefly touched on, but there is no description about technical knowledge such as the moving direction and moving speed.
[0004]
[Problems to be solved by the invention]
However, the method disclosed in Japanese Patent Application Laid-Open No. 11-16498 has the following problems.
When inspecting a phosphor defect on a PDP back plate, a plurality of video signals can be obtained by imaging defects or defects on the phosphor surface with one or more monochrome or color imaging devices. When a signal is processed by an image processing apparatus, it is necessary to develop each color within the image processing apparatus or to prepare a plurality of image processing apparatuses, which increases apparatus cost. In addition, when switching manually, switching is required every time inspection is performed, and the operation becomes complicated.
[0005]
Further, when inspecting by moving the image pickup means relative to the PDP back plate, a plurality of color signals and video signals from the plurality of image pickup means are transmitted. It takes time for replacement work due to deterioration.
[0006]
Also, when inspecting the PDP back plate, it is effective to capture and process a video signal using a one-dimensional camera, but if the same phosphor is moved in the same direction as the linearly extending direction, In particular, there is a possibility that a portion that becomes a shadow of the partition wall is generated in the peripheral portion of the imaging range, and the defect is overlooked.
[0007]
Further, when inspecting the PDP back plate, if the moving speed of the imaging device or the panel is inappropriate, the target resolution cannot be obtained, and the inspection accuracy is lowered.
[0008]
An object of the present invention is to solve the above-mentioned problems in the prior art, select a part from a plurality of video signals and perform image processing by switching, reduce the number of expensive image processing devices, The memory capacity in the processing equipment can be reduced, the equipment cost can be reduced, the wiring amount of the movable parts can be reduced and the replacement work at the time of maintenance can be facilitated, and high-precision inspection is possible. Another object of the present invention is to provide an inspection apparatus and manufacturing method for a plasma display panel back plate.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a plasma display panel back plate inspection apparatus according to the present invention is a device for inspecting a phosphor on a plasma display panel back plate, and an ultraviolet irradiation means for irradiating the phosphor with ultraviolet rays. , One or a plurality of color imaging means in which light receiving elements are arranged one-dimensionally, and three types corresponding respectively to R (red), G (green), and B (blue) phosphors output from the imaging means Video signal switching means for selecting one of R / G / B video signals from the video signal, and processing means for computing the video signal output from the video signal switching means for each pixel. , the processing means compares the video signal with a predetermined reference value, you characterized by examining on the basis of a difference between the reference value. Since the video signal switching means for selecting one type of video from a plurality of video signals obtained by one or a plurality of imaging devices is used when inspecting the phosphor defect on the PDP back plate, substantially. Inspection can be performed with one image processing apparatus, and the number of image processing apparatuses can be reduced and the memory capacity in the image processing apparatus can be reduced.
[0010]
The plasma display panel back plate inspection apparatus according to the present invention has moving means for relatively moving the imaging means and the plasma display back plate. In particular, the imaging means moves integrally with the movable part of the moving means. In this case, it is preferable that the video signal switching means also moves integrally.
[0011]
Further, when inspecting by moving the imaging means relative to the plasma display panel back plate, the moving direction of the imaging means by the moving means is the direction in which the phosphor layer on the plasma display panel back plate extends linearly. It has preferred to be a direction perpendicular to.
[0012]
The manufacturing method of the plasma display panel back plate according to the present invention includes a method of inspecting using the above-described inspection apparatus and discriminating between a non-defective product and a defective product based on the obtained defect information.
[0013]
Moreover, the manufacturing method of the plasma display panel back plate which concerns on this invention consists of the method of inspecting using the above inspection apparatuses, and repairing a fluorescent substance layer based on the obtained defect information.
[0014]
Furthermore, the manufacturing method of the back panel of the plasma display panel according to the present invention comprises a method of inspecting using the above-described inspection apparatus after each color layer forming step.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a plasma display panel back plate inspection apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a back plate of a plasma display panel to be used for inspection (hereinafter also abbreviated as a PDP back plate). The PDP back plate 1 has a back plate as shown in FIG. In addition, phosphors 305, 306, and 307 for R (red), G (green), and B (blue) are sequentially and repeatedly applied in a stripe shape.
[0016]
As shown in FIG. 3, the plasma display panel back plate mechanism 300 includes RGB phosphors 305, 306, 307 between the partition walls 304 on the dielectric layer 303 on which the address electrodes 302 are arranged on the back glass substrate 301. PDP rear plate 1 is repeatedly applied in the form of stripes, a front glass substrate 308 is provided above the rear plate 1, and a display electrode 309 is provided between the rear plate 1 and the front glass substrate 308. The disposed dielectric layer 310 and protective film 311 are interposed. Plasma 312 is generated by the voltage between the display electrode 309 and the address electrode 302, whereby the phosphor at the selected position is colored, and a desired color display is performed by the combination of the coloring of each phosphor. ing.
[0017]
The RGB phosphors 305, 306, and 307 are applied to the PDP back plate 1 by screen printing, for example, as shown in FIG. 4, and the excess amount of the phosphor applied through the printing screen 402 is scraped off with the squeegee 401. As a result, as shown in FIG. 3, each phosphor 305, 306, 307 is applied between the partition walls 304 by a predetermined amount.
[0018]
However, if the RGB phosphors 305, 306, and 307 are not applied as prescribed, color unevenness as shown in FIG. 5A may occur, for example, reddish color unevenness 501. Or bluish color unevenness 502 occurs. Further, as shown in FIG. 5B, in the arrangement of the RGB phosphors 305, 306, and 307, a portion 503 in which a certain color phosphor protrudes from a phosphor portion of the next color and color mixing occurs, or a paint is applied. There may be a portion where a dark spot 504 occurs due to wearing-out and a portion 505 where a color shift occurs.
[0019]
Various defects as described above in the application of the RGB phosphors 305, 306, and 307 to the PDP back plate 1 are inspected by the inspection apparatus shown in FIG. Referring to FIG. 1 again, the PDP back plate 1 is transported by a transport device 2 having a transport roller or the like as a relative moving means. This transport device 2 is for scanning the imaging range of the imaging device 4 provided above the transport device 2 over the entire surface of the PDP back plate 1, and transports the PDP back plate 1 at a constant speed.
[0020]
Above the transport device 2, an ultraviolet irradiation device 3 is provided for exciting and emitting the phosphor applied on the PDP back plate 1 and irradiating the PDP back plate 1 with ultraviolet rays. As an ultraviolet ray source, an excimer lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultraviolet laser, or the like can be selected. However, an excimer lamp having a wavelength of 222 nm is preferable because it generates less ozone and the RGB phosphor emits light in a balanced manner. . In addition, it is preferable to transmit ultraviolet rays using an optical fiber or the like because the configuration of the measuring head can be simplified.
[0021]
A plurality of imaging devices 4 are arranged, for example, like imaging devices 4 a, 4 b, 4 c, and are connected to the image processing device 6 via the video signal switching device 5. The control device 7 is connected to the substrate transport device 2, the lighting device 8 that controls the lighting of the ultraviolet irradiation device 3, and the image processing device 6, and controls these operations. The display device 9 is connected to the image processing device 6.
[0022]
The imaging device 4 divides a certain range on the PDP back plate 1 into pixels, measures the luminance for each pixel, converts it into an image signal, and transmits it to the image processing device 6. In order to obtain the respective images of the RGB phosphors, it is preferable to use a color line sensor camera because the optical system can be simplified.
[0023]
The video signal switching device 5 has one type of signal (1 of R / G / B) from each video signal (three types of R, G, B video signals) of the RGB phosphors obtained by the imaging device 4. Seed image signal) is selected and transmitted to the image processing device 6.
[0024]
The image processing device 6 is for detecting defects generated in the phosphor. The image processing device 6 inputs image signals of the RGB phosphors imaged by the imaging device 4 and performs image analysis by the processing technique according to the present invention. Detect defects.
[0025]
The control device 7 gives an operation command to the transport device 2, the ultraviolet irradiation device 3, the imaging device 4, and the image processing device 6 based on the determined procedure.
[0026]
The display device 9 is for displaying each piece of defect information detected by the image processing device 6.
[0027]
In the plasma display panel back plate inspection apparatus as described above, for example, as shown in FIG. 6, discrimination between a non-defective product and a defective product is performed based on the obtained defect information. Further, as necessary, the phosphor layer is repaired based on the obtained defect information. Therefore, it is preferable to inspect using the inspection apparatus for the back plate of the plasma display panel as described above after the formation process of each color of the phosphor layer.
[0028]
FIG. 6 shows an example of a signal when the differential processing is performed in the extending line direction of the phosphor layer. In the illustrated example, an example of detection of the dark spot defect 602 of the R color phosphor layer 601 is shown. . As shown in the figure, the signal of the R color phosphor layer 601 selected as the specific video signal by the video signal switching device 5 is output as a difference signal of the R signal strength from the R signal strength from the video signal switching device 5. Then, the difference signal is compared with a predetermined predetermined reference value, and an inspection is performed based on the difference from the reference value. That is, a portion where the difference signal exceeds a predetermined reference value is determined as a defect.
[0029]
In this way, the entire surface of the PDP back plate is inspected. For example, as shown in FIG. 7, the PDP back plate 21 is fixed, the imaging device 22 and the ultraviolet irradiation device 23 are moved on the XY gantry stage 24, and the entire surface of the PDP back plate 21 is inspected.
[0030]
As shown in FIG. 8, the PDP back plate 21 is fixed, and the imaging device 22, the ultraviolet irradiation device 23, and the video signal switching device 25 are integrally moved on the XY gantry stage 24 to inspect the entire surface of the PDP back plate 21. Can also be done. FIG. 9 shows an example in which the imaging device 22 is inspected by moving it in a direction perpendicular to the direction in which the phosphor partition walls 26 of the PDP back plate 21 extend.
[0031]
In addition, the inspection embodiment is not limited to the embodiment described above. For example, as shown in FIG. 10, the imaging devices 32 are arranged in a row with respect to the PDP back plate 31, and the imaging device 32 and the ultraviolet irradiation device 33 are arranged. On the other hand, when the PDP substrate 31 is transported by the transport device 34, the entire surface can be inspected. As described above, the relative position, the arrangement relationship, and the arrangement of the imaging devices between the imaging device, the ultraviolet irradiation device, and the PDP back plate can be set substantially arbitrarily.
[0032]
The operation of the inspection apparatus according to the present invention will be described with respect to the above-described embodiment. When the PDP back plate 1 is input from the upstream device to the transport device 2, the transport device 2 sends a PDP back plate input signal to the control device 7. Then, the conveyance of the PDP back plate 1 is started. When the PDP back plate insertion signal is input, the control device 7 operates the ultraviolet irradiation device 3. When the transport device 2 transports the PDP back plate 1 to the imaging position, the transport device 2 gives a PDP back plate approach signal to the control device 7 from the built-in detection sensor. When the PDP rear panel approach signal is input, the control device 7 gives an image capture start signal to the image processing device 6, and the video switching device 5 receives a plurality of video signals from the imaging device 4 in accordance with instructions from the control device 7. One video signal is selected and output from the image processing device 6, and the image processing device 6 starts to capture the image signal output from the video switching device 5. The image processing device 6 stores an image signal and detects a defect generated in the PDP back plate 1 by an image processing technique. The image processing device 6 gives an image capture end signal to the control device 7 after completing the image capture, and the control device 7 stops the ultraviolet irradiation device 3.
[0033]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to this.
Example 1
The ultraviolet irradiation device 3 used an excimer lamp enclosing Kr and Cr having a lighting frequency of 2 GHz and an irradiation ultraviolet central wavelength of 222 nm, and was installed at a position of 50 mm from the upper surface of the PDP back plate. The imaging device 4 used a 2048-pixel three-plate type color line sensor camera, and selected a lens so that one pixel corresponds to 75 μm on the PDP back plate. The PDP back plate 1 used a substrate containing printing defects and color unevenness, and was transported by the transport device 2 at 100 mm / s for inspection.
[0034]
In the example of FIG. 1, the color of the camera and video signal is selected from the three color line sensor cameras, switched to one type of video, and sent to the image processing apparatus. As a result of taking the difference between pixels adjacent in the direction of the stripe pattern on the PDP back plate from the captured image (FIG. 6), printing defects could be detected with high accuracy. By performing this operation sequentially for each camera and each color, defect inspection for all video signals was performed with one image processing apparatus. In addition, by performing differential processing at intervals of the stripe pattern of the phosphor in the direction perpendicular to the stripe direction of the PDP back plate, the amount of change in print defects and color unevenness becomes noticeable particularly in oblique cameras, and defects can be detected with high accuracy. It was.
[0035]
By selecting an arbitrary video signal and performing image processing by the video signal switching device, the number of image processing devices can be reduced, and the device cost can be reduced. Further, in the example (FIG. 8) in which the image pickup means and the video signal switching device are integrally fixed to the movable part, the number of wirings passing through the movable part is minimized, and the maintenance work at the time of replacement due to subsequent wiring deterioration or the like can be reduced. Furthermore, by making the direction perpendicular to the direction in which the partition walls of the PDP back plate extend, it becomes easier to detect light emission unevenness of the phosphor in particular, and the unevenness defect of the phosphor can be detected with high accuracy.
[0036]
Regarding the movement speed at the time of movement, taking into account a scanning time of 0.75 ms for one line of the line sensor camera of the imaging device 4 and a resolution of 75 μm on the PDP back plate,
1000 × 75 μm / 0.75 ms = 100 mm / s
It was. However, the inspection speed also depends on the inspection resolution, and 40 mm / s to 120 mm / s was effective as the inspection speed for detecting a resolution of 30 μm to 90 μm.
[0037]
【The invention's effect】
As described above, according to the plasma display panel back plate inspection apparatus and the manufacturing method according to the present invention, the following various effects can be obtained.
(1) A part of a plurality of video signals can be selected and switched to perform image processing. By reducing the number of expensive image processing apparatuses or reducing the memory capacity in the image processing apparatus, The device cost can be suppressed.
(2) When inspecting by moving the imaging device relative to the PDP back plate, moving the imaging device and the video switching device as one unit reduces the wiring amount of the movable part and facilitates replacement work during maintenance.
(3) Highly accurate inspection is possible by optimally setting the relative movement speed between the imaging device and the PDP back plate.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a plasma display panel back plate inspection apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic plan view of a plasma display panel back plate.
FIG. 3 is a partial longitudinal sectional view of a plasma display panel.
FIG. 4 is a perspective view for explaining a printing method of a phosphor on a back plate by a printing machine.
FIG. 5 is a diagram illustrating examples of various printing defects detected in a print inspection process.
FIG. 6 is a view showing an inspection example of a plasma display panel back plate.
FIG. 7 is a schematic perspective view showing an embodiment of an inspection in the present invention.
FIG. 8 is a schematic perspective view showing another inspection embodiment according to the present invention.
FIG. 9 is a schematic perspective view showing still another inspection embodiment according to the present invention.
FIG. 10 is a schematic perspective view showing still another inspection embodiment according to the present invention.
[Explanation of symbols]
1, 21, 31 Plasma display panel back plate 2, 34 Transport device 3, 23, 33 Ultraviolet irradiation device 4, 22, 32 Imaging device 5, 25 Image switching device 6 Image processing device 7 Control device 8 Lighting device 9 Display device 24 XY Gantry Stage 26 Phosphor Barrier 300 Plasma Display Panel Rear Plate Mechanism 301 Rear Glass Substrate 302 Address Electrode 303 Dielectric Layer 304 Barrier 305 Phosphor (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 Print screen 501 Uneven color (reddish part)
502 Color unevenness (blue part)
503 Mixed color portion 504 Dark spot 505 Deviation defect portion 601 Phosphor (R color)
602 Defect (dark spot)

Claims (7)

An apparatus for inspecting a phosphor on a plasma display panel back plate, the ultraviolet irradiation means for irradiating the phosphor with ultraviolet light, one or a plurality of color imaging means in which light receiving elements are arranged one-dimensionally, Video for selecting one video signal of R / G / B from three video signals corresponding to R (red), G (green), and B (blue) phosphors output from the imaging means Signal switching means, and processing means for computing a video signal output from the video signal switching means for each pixel,
The processing means compares the video signal with a predetermined reference value and inspects based on a difference from the reference value.   The apparatus for inspecting a back panel of a plasma display panel according to claim 1, further comprising moving means for relatively moving the imaging means and the back panel of the plasma display.   3. The apparatus for inspecting a rear panel of a plasma display panel according to claim 2, wherein the video signal switching means and the imaging means move together with the movable part of the moving means.   The moving direction of the imaging means by the moving means is a direction perpendicular to the direction in which the phosphor layer on the plasma display panel back plate extends linearly. Inspection device. A method for manufacturing a back plate of a plasma display panel, wherein inspection is performed using the inspection apparatus according to any one of claims 1 to 4 and a non-defective product and a defective product are discriminated based on the obtained defect information. It inspected using the inspection device according to any one of claims 1-4, perform repair of the phosphor layer on the basis of the obtained defect information, the method for manufacturing a plasma display panel back plate. The manufacturing method of the plasma display panel back plate which test | inspects using the test | inspection apparatus in any one of Claims 1-4 after the formation process of each color of a fluorescent substance layer.

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