JP2007085834A - Inspection device of phosphor panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect the missing of a phosphor or printing shift in an inspection device for inspecting the coating state of the phosphor in the phosphor panel used in a display device. <P>SOLUTION: One side of the phosphor panel 2 becoming an inspection target is irradiated with ultraviolet rays by an ultraviolet irradiation means 4 and the phosphor panel 2 becoming the inspection target is irradiated with white light from one side by a white light irradiation means 5. Imaging means 7 and 8 capture an image from the side of the surface opposite to the side of the surface irradiated with ultraviolet rays or white light with respect to the phosphor panel 2 serving as the inspection target. A detection means 12 detects that the emission color due to the phosphor 3 must be imaged but the abnormality of the phosphor is present at the position on the surface of the phosphor panel 2 corresponding to a pixel which represents another color imaged on the basis of the images photographed by imaging means 7 and 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the present invention, for example, a fluorescent paint is applied in a display device (hereinafter referred to as a field emission display) which emits electrons from a planar electron emission source (emitter) in a vacuum to excite a phosphor to emit light. The present invention relates to an inspection apparatus that inspects a panel (phosphor panel), and more particularly, to an inspection apparatus that inspects phosphors for missing or misprinting.

For example, a field emission display or the like is configured using a phosphor panel.
FIG. 4 shows a configuration example of an inspection apparatus for inspecting a phosphor panel for a field emission display.
A phosphor panel 22 for field emission display is placed on the mounting table 21. Above the phosphor panel 22, an ultraviolet illumination unit 23 that irradiates ultraviolet rays to emit light from the phosphor applied to the phosphor panel 22, a lens 24, a color camera 25, an ultraviolet illumination unit 23, and a lens 24. And a moving mechanism unit 26 for moving the color camera 25 on the phosphor panel 22 is provided.
In addition, a driving unit 27 for driving the moving mechanism unit 26, a control unit 28 for controlling the driving unit 27, an image processing unit 29, a display 30 for displaying a processing result by the image processing unit 29, and image processing An operation unit 31 for operating the unit 29 is provided.

An operation example of the inspection apparatus of this example is shown.
The phosphor surface on the phosphor panel 22 is irradiated with ultraviolet rays from the ultraviolet illumination unit 23 to emit light from the phosphor surface. Light emitted from the light emitting surface is picked up by the color camera 25 through the lens 24.
Under the control of the control unit 28, the driving unit 27 drives the moving mechanism unit 26 to move the ultraviolet illumination unit 23, the lens 24, and the color camera 25 on the phosphor panel 22. As a result, the captured image of the phosphor surface emitted on the phosphor panel 22 is sent to the image processing unit 29.
The image processing unit 29 performs image processing on the sent image, and inspects phosphors for missing or misprinting (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 2004-233213

However, in the inspection apparatus as shown in FIG. 4, when inspecting the light emitting surface of the phosphor, there is a problem that, for example, the lack of the phosphor or the printing misalignment on the display surface as a field emission display cannot be detected. . Therefore, it is necessary to develop an inspection apparatus that enables such inspection.
Specifically, as shown in FIGS. 5A and 5B, in the field emission display, display is performed by the light emitted from the phosphor 43 through the window 42 provided in the panel 41. Further, it was not possible to detect the loss of the phosphor 43 or the printing deviation with respect to the position of the window 42.

  The present invention has been made in order to solve such a conventional problem, and provides an inspection apparatus capable of inspecting phosphor missing or printing deviation for a phosphor panel used in a field emission display or the like. The purpose is to do.

In order to achieve the above object, the phosphor panel inspection apparatus according to the present invention inspects the application state of the phosphor on the phosphor panel used in the display device with the following configuration.
The ultraviolet irradiation means irradiates the phosphor panel to be inspected with ultraviolet rays from one side. White light irradiating means irradiates the phosphor panel to be inspected with white light from the one surface side. The imaging means captures an image from the side of the surface opposite to the surface irradiated with the ultraviolet light and the white light with respect to the phosphor panel to be inspected. Based on the image picked up by the image pickup means, the detection means should pick up the emission color of the fluorescent substance, but at a position on the surface of the phosphor panel corresponding to the pixel in which the other color was picked up. Detect the presence of phosphor abnormality.
Therefore, a pixel in which a color emitted by a phosphor is supposed to be imaged but another color is imaged is detected, and a phosphor abnormality exists at a position corresponding to the pixel on the surface of the phosphor panel. By detecting this, for example, an abnormality in the application state of the phosphor can be detected with respect to a phosphor panel used in a field emission display or the like, and it is possible to inspect the lack of the phosphor and the printing misalignment.

Here, various types of display devices such as a field emission display may be used.
Various types of phosphor panels may be used. For example, a panel provided with a window that divides an area to be displayed by light emission from the phosphor may be used.
In addition, as the surface of the phosphor panel that is irradiated with ultraviolet light or white light, for example, a surface opposite to the surface with the window can be used for the phosphor panel with a window. In this case, the image to be picked up is due to the light that has passed through the window.
In addition, for example, there are provided means for moving the position for irradiating the ultraviolet rays by the ultraviolet irradiation means, means for moving the position for irradiating white light by the white light irradiation means, and means for moving the position for taking an image by the imaging means. You can also.

Further, for example, information for specifying the color of the luminescent color by the phosphor is set in advance using the RGB system or chromaticity and luminance.
In addition, as a pixel or a position on the surface of the phosphor panel on which the emission color of the phosphor is to be imaged, a pixel on which the phosphor is originally applied and an emission color from the phosphor is expected to be imaged or It corresponds to the position on the surface of the phosphor panel. For this reason, when the luminescent color from a fluorescent substance is not imaged about the position on the surface of such a pixel or a fluorescent substance panel, it can be considered that it is not a normal application state but an abnormal application state.
In addition, as the position on the surface of the pixel or phosphor panel where the emission color of the phosphor is to be imaged, for example, for a phosphor panel with a window, the pixel or phosphor panel corresponding to the inside of the window The position on the surface can be used. In this case, for example, information for specifying the position of the window is set in advance, or the position of the window is estimated by image processing or the like.

  In addition, various modes may be used as a mode of detecting an abnormality of the phosphor based on the captured image. For example, the emission color of the phosphor should be captured but white is captured. When there is a pixel, an aspect of detecting the absence of a phosphor at a position on the surface of the phosphor panel corresponding to the pixel, or a primary emission color by the phosphor should be imaged. A mode in which when there is a pixel in which a mixed color (in this case, other than white) is captured, it is detected that there is a printing deviation of the phosphor at a position on the surface of the phosphor panel corresponding to the pixel. Etc. can be used.

  As described above, according to the phosphor panel inspection apparatus of the present invention, when inspecting the application state of the phosphor in the phosphor panel used in the display device, Irradiate ultraviolet light and white light from the side of the surface, and take an image from the side of the other surface. Based on the captured image, the emission color of the phosphor should be imaged, but other colors are imaged. For example, a phosphor panel used in a field emission display or the like is detected by detecting the presence of a phosphor abnormality at a position on the surface of the phosphor panel corresponding to the pixel. It is possible to inspect for missing bodies and misprints.

Embodiments according to the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration example of an inspection apparatus for inspecting a phosphor panel for a field emission display as an embodiment of the present invention.
In the inspection apparatus of this example, the lack of phosphors and the printing misalignment on the surface actually displayed as the field emission display are detected.
The inspection apparatus of this example includes a mounting table 1, an ultraviolet illumination unit 4, a white illumination unit 5, and a movement mechanism unit (first movement mechanism unit) 6 for moving the ultraviolet illumination unit 4 and the white illumination unit 5. A lens 7, a color camera 8, a moving mechanism unit (second moving mechanism unit) 9 for moving the lens 7 and the color camera 8, a driving unit 10, a control unit 11, and an image processing unit 12. And a display unit 13 and an operation unit 14.
In addition, a phosphor panel 2 for field emission display coated with a phosphor 3 is placed on the mounting table 1. The phosphor panel 2 has a configuration as shown in FIG. 5A, for example.

The mounting table 1 is a table on which a phosphor panel 2 for field emission display is mounted. In this example, the surface on which the phosphor 3 is applied to the phosphor panel 2 is directed downward. The phosphor panel 2 is placed.
The ultraviolet illuminating unit 4 is provided below the mounting table 1 and irradiates ultraviolet rays for causing the phosphor 3 applied to the placed phosphor panel 2 to emit light.
The white illumination unit 5 is provided below the mounting table 1 and irradiates white light to the placed phosphor panel 2.
The first moving mechanism unit 6 moves the ultraviolet illumination unit 4 and the white illumination unit 5 below the phosphor panel 2. In this example, the position where irradiation from the ultraviolet illumination unit 4 or the white illumination unit 5 hits the surface of the phosphor panel 2 can be arbitrarily moved.

The lens 7 is provided above the mounting table 1.
The color camera 8 is provided above the mounting table 1 and captures a color image with light input via the lens 7.
The second moving mechanism unit 9 moves the lens 7 and the color camera 8 above the phosphor panel 2. In this example, the position on the phosphor panel 2 to be imaged can be arbitrarily moved by the lens 7 and the color camera 8.

The driving unit 10 drives the first moving mechanism unit 6 and the second moving mechanism unit 9.
The control unit 11 controls the drive unit 10.
The image processing unit 12 inputs image data captured by the lens 7 and the color camera 8 and performs image processing.
The display unit 13 displays the result of the image processing performed by the image processing unit 12 on the screen.
The operation unit 14 includes, for example, a key operated by a person (operator), a mouse, and the like, and receives operations related to image processing performed by the image processing unit 12.

An example of the operation performed by the inspection apparatus of this example is shown.
The surface of the phosphor 3 on the phosphor panel 2 for field emission display is irradiated with ultraviolet rays from the ultraviolet illumination unit 4 to cause the phosphor 3 on the phosphor surface to emit light. Further, white light is emitted from the white illumination unit 5 to brighten the phosphor surface. An image of this transmission surface is picked up by the color camera 8 through the lens 7.
Controlled by the control unit 11, the drive unit 10 drives the first moving mechanism unit 6 to move the ultraviolet illumination unit 4 and the white illumination unit 5 under the phosphor panel 2. At the same time, the control unit 11 controls the driving unit 10 to drive the second moving mechanism unit 9 to move the lens 7 and the color camera 8 on the phosphor panel 2.

In this example, the irradiation position from the bottom of the phosphor panel 2 and the imaging position on the phosphor panel 2 correspond to each other over the entire region of the surface of the phosphor panel 2 or the region requiring inspection. Control is performed so that the first moving mechanism unit 6 and the second moving mechanism unit 9 are moved.
As a result, the captured image of the transmission surface emitted from the phosphor panel 2 is sent to the image processing unit 12.
The image processing unit 12 performs image processing on the sent image and inspects the lack of the phosphor 3 and the printing deviation.

With reference to FIG. 2, an example of the procedure of the inspection process performed by the image processing unit 12 of this example will be described.
(Process S1) A grayscale image is calculated from the input image Img (h, v) of the color camera 8.
If the grayscale image is yImg (h, v), it is expressed as in Equation 1.
(Equation 1)
yImg (h, v)
= MAX [R (h, v) / R (h, v) max × 255
G (h, v) / G (h, v) max × 255
B (h, v) / B (h, v) max × 255]
・ ・ (Formula 1)

Here, MAX [] indicates that the maximum value is calculated among those arranged in [] separated by commas (,).
R (h, v) indicates the R component of the input image Img (h, v) of the camera.
R (h, v) max indicates the maximum value of the R component of the input image Img (h, v) of the camera.
G (h, v) indicates the G component of the input image Img (h, v) of the camera.
G (h, v) max indicates the maximum value of the G component of the input image Img (h, v) of the camera.
B (h, v) indicates the B component of the input image Img (h, v) of the camera.
B (h, v) max indicates the maximum value of the B component of the input image Img (h, v) of the camera.
(H, v) indicates the coordinate position on the surface of the phosphor panel 2. h indicates the coordinate position in the horizontal direction H, and v indicates the coordinate position in the vertical direction V.

In this example, the color of the phosphor 3 applied to the phosphor panel 2 is recognized in advance, and automatic adjustment is not performed for colors that are not applied.
For example, when the R and G phosphors 3 are applied and the B phosphor is not applied, Equation 1 is replaced with Equation 2 for calculation.
(Equation 2)
yImg (h, v)
= MAX [R (h, v) / R (h, v) max × 255
G (h, v) / G (h, v) max × 255
B (h, v)]
.. (Formula 2)

(Process S2) A binarization process is performed.
If the grayscale image yImg (h, v) is equal to or greater than the arbitrary threshold Yth, it is determined that the phosphor 3 is applied to the pixel at that position. In other words, the binarized image is set to y2Img (h, v), and the determination as in Expression 3 is performed.
(Equation 3)
If yImg (h, v) ≧ Yth,
y2Img (h, v) = 1,
If yImg (h, v) <Yth,
Let y2Img (h, v) = 0.
.. (Formula 3)

(Process S3) By performing a labeling process, an area where the phosphor 3 is applied is extracted.
In this example, it is determined that the pixel collection area where the binarized image y2Img (h, v) is 1 is an area where the phosphor 3 is applied, and the binarized image y2Img (h, v) It is determined that the aggregate region of pixels in which 0 is 0 is a region where the phosphor 3 is not applied.

(Process S4) After extracting the region to which the phosphor 3 is applied (in this example, a plurality of regions corresponding to each window), a window provided in the phosphor panel 2 for each extracted region Measure the size.
In this example, the size of the window is calculated based on the number of pixels H in the h direction and the number of pixels V in the v direction for each labeled region using Equation 4.
Here, α is the magnification (μm / pixel) of one pixel in the h direction.
Β is a magnification (μm / pixel) of one pixel of the camera in the v direction.
(Equation 4)
Window size = (H × α) × (V × β)
.. (Formula 4)

(Process S5) For all the pixels in each extracted region (in this example, in each window), the RGB values (r, g, b) of the input image from the color camera 8 are converted to chromaticity x, y. And luminance Y.
FIG. 3A shows an example of converting RGB camera input values (r, g, b) into chromaticity x, y and luminance Y on the hv plane.
FIG. 3B shows an example of a chromaticity diagram in which chromaticity x is the horizontal axis and chromaticity y is the vertical axis.

(Processing S6) For all the pixels of the image acquired by the color camera 8, a pixel in the white area where the chromaticities x and y are registered in advance is extracted to detect the lack of the phosphor 3.
In this example, the missing portion of the phosphor 3 is not actually present in the portion where the phosphor 3 should emit light, so that the white illumination light enters the color camera 8. The image appears white. Paying attention to this, the lack of the phosphor 3 is detected depending on whether or not data exists in the white portion in the chromaticity diagram.
FIG. 3C shows an example of an image and a chromaticity diagram in a normal state in which the phosphor 3 is not missing. In this state, no white portion appears.
FIG. 3D shows an example of an image and a chromaticity diagram in a state where the phosphor 3 is missing. In this state, a white portion appears and it is determined that the phosphor 3 is missing at the pixel position corresponding to the white portion.

(Process S <b> 7) For all the pixels of the image acquired by the color camera 8, the printing deviation of the phosphor 3 is detected by extracting the pixels in the color deviation area where the chromaticities x and y are registered in advance. To do.
In this example, as in the case where the missing portion of the phosphor 3 is detected, is data originally present in the color mixture portion other than red (R), green (G), and blue (B) that the phosphor 3 emits light? Whether or not printing of the phosphor 3 is detected is determined depending on whether or not it is present.
Further, FIG. 3E shows an example of an image and a chromaticity diagram in a state where there is a printing deviation of the phosphor 3. In this state, for example, a yellow portion appears, and it is determined that printing deviation of the phosphor 3 has occurred at the pixel position corresponding to the yellow portion.

(Process S8) The presence / absence of a defect is determined according to the size of the pixel region extracted as the missing portion of the phosphor 3 and the size of the pixel region extracted as the printing misalignment portion of the phosphor 3.
For example, a mode in which the number of pixels included in such a pixel region is a predetermined number or more is a defect, and when the number is less than a predetermined number, a mode in which the pixel region is not defective, or such a pixel region In the case where the number of pixels in at least one of the h direction and the v direction is greater than or equal to a predetermined number, an aspect such as a defect can be used.

As described above, in the inspection apparatus of this example, when the application state of the phosphor 3 is inspected for the phosphor panel 2 for field emission display, the absence of the fluorescent paint is detected, or the printing deviation of the fluorescent paint is detected. It can be detected and the size of the window of the phosphor panel 2 can be detected.
For example, in the conventional inspection apparatus, when inspecting the light emitting surface of the phosphor, it was not possible to inspect the lack of the phosphor or the printing deviation on the surface actually displayed as the field emission display. Then, it is possible to inspect the lack of the phosphor 3 on the surface actually displayed as the field emission display and the printing deviation, and it is also possible to measure the size of the window provided on the surface of the phosphor panel 2.

  In the inspection apparatus of this example, the ultraviolet irradiation means is configured by the function of the ultraviolet illumination unit 4, and the white light irradiation unit is configured by the function of the white illumination unit 5, and the function of the lens 7 and the color camera 8. The imaging unit is configured by the function of, and the detection unit is configured by the function of the image processing unit 12. The first moving means is configured by the function of the driving unit 10 and the function of the first moving mechanism unit 6, and the second moving unit is configured by the function of the driving unit 10 and the function of the second moving mechanism unit 9. Is configured.

Here, the configuration of the inspection device, the display device, the phosphor panel, and the like according to the present invention is not necessarily limited to those described above, and various configurations may be used. The present invention can also be provided as, for example, a method or method for executing the processing according to the present invention, a program for realizing such a method or method, or a recording medium for recording the program. It is also possible to provide various devices and systems.
The application field of the present invention is not necessarily limited to the above-described fields, and the present invention can be applied to various fields.
Further, as various processes performed in the inspection apparatus according to the present invention, for example, control is performed by a processor executing a control program stored in a ROM (Read Only Memory) in a hardware resource including a processor, a memory, and the like. For example, each functional unit for executing the processing may be configured as an independent hardware circuit.
The present invention can also be understood as a computer-readable recording medium such as a floppy (registered trademark) disk or a CD (Compact Disc) -ROM storing the control program, and the program (itself). The processing according to the present invention can be performed by inputting the program from the recording medium to the computer and causing the processor to execute the program.

It is a figure which shows the structural example of the test | inspection apparatus of the fluorescent substance panel for field emission displays which concerns on one Example of this invention. It is a figure which shows an example of the procedure of the test | inspection process performed by an image process part. (A), (b) is a figure for demonstrating a chromaticity diagram, (c), (d), (e) is a figure which shows the example of the chromaticity diagram in each state. It is a figure which shows the structural example of the inspection apparatus of the fluorescent substance panel for field emission displays. (A), (b) is a figure for demonstrating the fluorescent substance panel for field emission displays.

Explanation of symbols

  1, 21 .. Placement table, 2, 22 .. Phosphor panel for field emission display, 3, 43 .. Phosphor, 4, 23 .. Ultraviolet illumination section, 5.. White illumination section, 6, 9, 26 .... Movement mechanism, 7, 24 ... Lens, 8, 25 ... Color camera 10, 27 ... Driver 11, 28 ... Control unit 12, 29 ... Image processing unit 13, 30 ..Display unit, 14, 31..Operating unit, 41..Panel, 42..Window,

Claims (1)

In the inspection apparatus for inspecting the application state of the phosphor in the phosphor panel used in the display device,
UV irradiation means for irradiating UV light from one side to the phosphor panel to be inspected,
White light irradiation means for irradiating the phosphor panel to be inspected with white light from the one surface side;
Imaging means for capturing an image from the side opposite to the side irradiated with the ultraviolet light and the white light with respect to the phosphor panel to be inspected,
Based on the image picked up by the image pickup means, the emission color of the phosphor should be picked up, but the phosphor is abnormal at a position on the surface of the phosphor panel corresponding to the pixel picked up with another color. Detecting means for detecting the presence of
An inspection apparatus comprising:

Images