KR20030064298A - Fluorescent material detecting method and apparatus - Google Patents

Abstract

In the inspection of the coating unevenness of the phosphor stripe applied to a glass substrate such as a plasma display, in order to cause the moire phenomenon caused by the non-light-emitting portion of the phosphor coated in the stripe shape and to emit light of the phosphor stripe. There is a problem that the coating unevenness of the phosphor stripe cannot be properly inspected by the illumination unevenness of the ultraviolet light used.

A plurality of stripe-shaped phosphors formed on the substrate are irradiated with ultraviolet rays, photographing light emitted from the stripe-shaped phosphors, the signal level of the photographed image is detected, and correspond to a signal level equal to or greater than a predetermined value of the signal level. The fluorescent substance inspection method which calculates the average value of the said part, and detects the coating | dyeing of the said stripe-shaped fluorescent substance based on the calculated average value.

Description

Phosphor Testing Method and Phosphor Testing Equipment {FLUORESCENT MATERIAL DETECTING METHOD AND APPARATUS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor inspection method and a phosphor inspection apparatus, and more particularly, to a phosphor inspection method and a phosphor inspection apparatus for inspecting a coating defect of a phosphor applied to a glass substrate such as a plasma display.

An example of the prior art will be described with reference to FIG. 3. 3 is a block diagram showing a schematic configuration of a phosphor inspection apparatus for inspecting a coating defect of a phosphor coated on a glass substrate such as a plasma display.

In Fig. 3, reference numeral 31 denotes a glass substrate coated with a phosphor, reference numeral 32 denotes a photographing unit made of a CCD camera, etc., reference numeral 33 denotes an optical system and reference numeral 34 of the photographing unit 32. The reference numeral 35 denotes an ultraviolet illuminating unit which emits phosphors, the reference numeral 35 denotes an image processing unit which detects coating spot defects, and the reference numeral 36 denotes a display unit which displays an inspection result. It is also possible to configure a printer (printer) instead of the display unit. Reference numeral 37 is an operation unit of the phosphor inspection device.

5 is a diagram for explaining a phosphor coating surface of a plasma display. In Fig. 5, reference numeral 21 denotes a substrate on which a phosphor of a plasma display is applied, for example, a glass substrate. Reference numeral 22 is a red phosphor coating layer (hereinafter referred to as R phosphor stripe) coated on the substrate 21 in a stripe shape (or slit shape), and reference numeral 23 is a stripe shape on the substrate 21. The applied green phosphor coating layer (hereinafter abbreviated as G phosphor stripe) and reference numeral 24 are blue phosphor coating layers (hereinafter abbreviated as B phosphor stripe) applied to the substrate 21 in a stripe shape. Reference numeral 25 denotes a portion (hereinafter referred to as a partition wall) between the R, G, and B phosphor stripes. As described above, the phosphor coating surface of the plasma display has a structure in which R, G, and B phosphor stripes 22, 23, and 24 are periodically arranged on the substrate 21 with the partition walls 25 interposed therebetween. This structure is hereinafter referred to as plasma display emitting surface.

In the conventional phosphor inspection apparatus, electron emission light is irradiated on all the display surfaces of the plasma display light emitting surface to emit light of the phosphor strip applied on the substrate. For example, as shown in FIG. 5, ultraviolet rays output from the ultraviolet illuminator 34 are irradiated to all the display surfaces of the plasma display light emitting surface to emit the phosphor strips applied on the substrate 21. That is, the R phosphor stripe 22 emits red, the G phosphor stripe 23 emits green, and the B phosphor stripe 24 emits blue.

The photographing unit 32 photographs the plasma display emitting surface in the state of being emitted through the optical system 33, and transmits the image signal obtained therefrom to the image processing unit 35. At this time, depending on the type of fluorescent paint (red (R), green (G), blue (B)) of the phosphor stripe to be detected, the imaging unit 32 uses a color filter corresponding to each phosphor stripe in the optical system. 33, an output signal of each color is obtained.

The image processing unit 35 calculates the maximum luminance, the minimum luminance, the average value, the deviation, and the like from the input image signal, detects the luminance unevenness according to the calculation result, and outputs the detected luminance unevenness information to the display unit 36. . In addition, the maximum brightness, the minimum brightness, an average value, a deviation, etc. are mentioned later.

By the way, as described above, when the plasma display emitting surface is inspected by the phosphor inspection apparatus, for example, when the R phosphor stripe 22 is inspected, a red filter is attached to the optical system 33, and from the R phosphor stripe 22 Since only the light emission signal is detected by the imaging unit 32, the captured image of the partition 25 portion and the portion of the phosphor stripe of G and B becomes dark. The portions of the phosphor stripes of G and B originally emit light, but since the red filter is attached, the light emission is not detected in the imaging section 6. Therefore, the part of the partition 25 and the part of the phosphor stripe of G and B are called a non-light emitting part.

Therefore, a method of averaging (eg, integrating a luminance signal level of a predetermined period of time) the luminance signal of a photographed image with a spatial filter or the like is known for the evaluation of the entire surface unevenness of the plasma display light emitting surface. (Interference) phenomenon occurred, and there was a problem such as incorrect detection of the generated moire with a coating stain.

4 shows an image when the R phosphor stripe 22 is photographed through a red filter by the photographing unit 32 using a CCD camera. As can be seen from this image, it can be seen that the moire phenomenon occurs on the entire surface of the light emitting surface 42 of the plasma display 41.

In addition, since the ultraviolet illuminating unit 34 is provided on both sides of the glass substrate 31 to which the phosphor is applied to irradiate ultraviolet rays, the ultraviolet rays are not uniformly irradiated on the glass substrate 31, so that illumination irregularities are generated, resulting in uneven coating. It is also a cause of detection.

In addition, as a method of inspecting a plasma display panel (for example, refer to Patent Document 1), a method of inspecting coating unevenness of R, G, and B phosphors using a color television camera or a monochrome television camera is known. No mention is made of this.

For example, Japanese Patent Application Laid-Open No. 11-16498 (4th, 5th pages, 1st, 8th, 13th degrees) discloses the occurrence of moiré phenomenon and electromagnetic waves or particle beams (for example, ultraviolet rays) uniformly in the photographed image. There was a flaw in which false detection or the like caused by not being produced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a phosphor inspection method and a phosphor inspection apparatus for reducing the moiré phenomenon caused by the influence of the non-light-emitting portion of the phosphor coated in the stripe shape, and performing the detection of the coating stain of the phosphor coated in the stripe shape with high accuracy. It is in doing it.

It is another object of the present invention to provide a phosphor inspection method and a phosphor inspection apparatus which reduce the illumination unevenness of illumination such as ultraviolet rays and detect the unevenness of coating of the phosphor coated in a stripe shape with high accuracy.

In the phosphor inspection method of the present invention, a plurality of stripe-shaped phosphors formed on a substrate are irradiated with electron radiation light (electromagnetic waves or particle beams) such as ultraviolet rays to photograph light emitted from the stripe-shaped phosphors, It is achieved by detecting a signal level, calculating an average value of portions corresponding to a signal level equal to or greater than a predetermined value of the signal level, and detecting coating unevenness of the stripe-shaped phosphor based on the calculated average value.

In the phosphor inspection method of the present invention, the average value of the portion corresponding to the signal level equal to or greater than the predetermined value of the signal level is calculated for each predetermined section.

In the phosphor inspection method of the present invention, the plurality of stripe-shaped phosphors is at least one kind of phosphor stripe among R, G, and B phosphor stripes, and the predetermined section is substantially the same as the repeating period of the phosphor stripes.

In the phosphor inspection method of the present invention, the maximum value of the signal level equal to or greater than the predetermined value of the signal level is detected, and the maximum value is set as the predetermined section.

Further, in the phosphor inspection method of the present invention, the maximum signal level, the minimum signal level, the average value and the deviation are calculated from the signal level of the photographed image, and the coating unevenness of the phosphor stripe is detected based on the calculation result.

In addition, the phosphor inspection apparatus of the present invention includes an irradiation unit for irradiating electromagnetic waves or particle beams such as ultraviolet rays to a plurality of stripe-shaped phosphors formed on a substrate, a photographing unit for photographing light emitted from the stripe-shaped phosphors, and the photographing unit. In a phosphor inspection apparatus comprising an image processing unit for processing a processed image signal, the photographing portion is made of a line sensor moving in the direction of the stripe, the image processing portion detects the signal level of the photographed image, the signal level This is achieved by calculating an average value of portions corresponding to a signal level equal to or greater than a predetermined value of and detecting the coating unevenness of the stripe-shaped fluorescent substance based on the calculated average value.

Further, in the phosphor inspection apparatus of the present invention, the image processing unit is configured by means for calculating an average value of portions corresponding to signal levels equal to or greater than a predetermined value of the signal level for each predetermined section of the image signal.

Further, in the phosphor inspection apparatus of the present invention, the plurality of stripe shaped phosphors is at least one kind of phosphor stripe among R, G, and B phosphor stripes, and the image processing unit is the predetermined same as the repetition period of the phosphor stripes. And means for detecting an interval of.

Further, in the phosphor inspection apparatus of the present invention, the image processing section has a level detection section that detects a maximum value of a signal level equal to or greater than a predetermined value of the signal level and sets the maximum value between the predetermined sections.

Further, in the phosphor inspection apparatus of the present invention, the image processing section has a level detection section and a coating spot detection section, and the level detection section calculates a maximum signal level, a minimum signal level, an average value, and a deviation from the signal level of the photographed image. The coating spot detection unit is configured to detect the coating spot of the phosphor stripe based on the calculation result.

1 is a block diagram illustrating one embodiment of the present invention.

2 is a diagram showing luminance signal waveforms for explaining the principle of the present invention.

3 is a block diagram showing a schematic configuration of an example of a conventional phosphor inspection apparatus.

4 is a diagram illustrating an example of generation of moiré phenomena of an image photographed by a conventional phosphor inspection apparatus.

5 is a diagram for explaining a phosphor coating surface of a plasma display.

6 is a view for explaining the operation of the present invention.

7 is an enlarged view of a portion of an embodiment of the present invention.

8 is a view for explaining the principle of the present invention.

Explanation of symbols for the main parts of the drawings

1 Glass substrate mounting base 2, 21 Glass substrate

3: phosphor stripe 4: ultraviolet light source

5: optical system 6: photographing unit

7 moving mechanism 8 image processing unit

9 display unit 10 drive unit

11 control unit 12 level detection unit

13: Averaging process part 14: Coating spot detection part

15: control panel 22: R phosphor stripe

23: G phosphor stripe 24: B phosphor stripe

25: bulkhead

1 is a view showing an embodiment of the phosphor inspection apparatus of the present invention. In Fig. 1, reference numeral 1 denotes a mounting table for a glass substrate such as a plasma display, reference numeral 2 denotes a glass substrate such as a plasma display, reference numeral 3 denotes a phosphor stripe of R, G, and B, and a reference numeral. Reference numeral 4 denotes an ultraviolet light source for emitting the phosphor strip 3, reference numeral 5 denotes an optical system in which lenses and color filters of R, G and B are sequentially mounted, reference numeral 6 denotes a line sensor for photographing. A photographing part such as a camera, reference numeral 7 is a moving mechanism part for scanning the photographing part 6 and the light source 4 onto the glass substrate 2 along the glass substrate 2, and the reference numeral 8 is applied. The image processing unit for detecting the unevenness and the reference numeral 9 are display units such as a color monitor for displaying the inspection results, and may be constituted by printing units such as a printer. Reference numeral 10 is a driving unit for driving the moving mechanism unit 7, reference numeral 11 is a control unit for controlling the image processing unit and the driving unit, and reference numeral 15 is an operation unit. In addition, the image processing part 8 is comprised by the level detection part 12 which detects luminance signal levels, such as a maximum value and a minimum value, the averaging processing part 13, and the coating | staining stain detection part 14, as mentioned later. In addition, although the apparatus which drives the imaging | photography part 6 by the drive part 7 was demonstrated in this embodiment, it is also what fixes the imaging | photography part 6, and drives the mounting table 1 of the glass substrate 2 to drive. It is possible.

FIG. 7 shows an enlarged view of the mounting table, the glass substrate, and the imaging unit of the phosphor inspection apparatus shown in FIG. 1, and the same reference numerals are assigned to the same ones as in FIG. 1. Although the mounting table 1 mounts the glass substrate 2 at the time of inspection, when the fluorescent stripe of red (R) is applied to the glass substrate which is a plasma display panel, for example, in order to test the application | coating state, it shows by the arrow. The glass substrate to which the red (R) phosphor stripe was applied in the direction is conveyed, is fixed at a predetermined position shown in FIG. 7, and coating unevenness is inspected. The same inspection is carried out on the line applying the green (G) phosphor strip and the line applying the blue (B) phosphor strip. In addition, in the present Example, although the size of a glass substrate is a thing of the size of 1460 mm x 1030 mm, it is not limited to this.

Reference numeral 71 is a part of the moving mechanism part 7 and is a supporting member for supporting the imaging section 6 and the ultraviolet light source 4. The imaging | photography part 6 is comprised so that four line sensor cameras may be arrange | positioned in a line like a tile | tip, and the glass substrate of width 1030mm is covered for inspection of a single glass substrate. The shooting width of one line sensor camera is about 260 mm, and the field of view between the line sensor cameras is partially overlapped. Ultraviolet light 72 from the ultraviolet light source 4 is reflected by the glass substrate 2, and the image of the phosphor strip 3 of red color R is photographed by the imaging unit 6 via the optical system 5. The supporting member 71 moves at a constant velocity in the longitudinal direction of the phosphor strip 3 of red color (R), for example, on the Y axis of the glass substrate 2 from the right end to the left end, and scans the entire glass substrate.

This operation will be described. The ultraviolet ray 72 is irradiated to the glass substrate 2, such as a plasma display, by the ultraviolet-illumination light source 4, and the stripe fluorescent substance 3 apply | coated or printed is light-emitted. The emitted image is captured by the photographing unit 6. At this time, according to the types R, G, and B of the phosphor to be detected, it is as described above to mount the color filter corresponding to the phosphor of each color in the imaging unit 6. The image photographed by the photographing unit 6 is sent to the image processing unit 8.

Hereinafter, the operation of the phosphor inspection apparatus of FIG. 1 will be described in detail with reference to FIGS. 2, 6, and 8. FIG. 6 shows a plasma display emitting surface in which phosphor stripes are applied on the glass substrate 21 of the present invention, and shows a state in which the line sensor camera moves on the line A in the direction of the arrow 61. FIG. . In addition, although FIG. 6 has shown the state in which all the fluorescent stripe of R, G, and B was apply | coated, it is not limited that all the fluorescent stripe is apply | coated by the application | coating process.

8 shows a part of the cross section of the plasma display light emitting surface on the line A, and the same reference numerals are given to the same members as in FIG. In addition, the pitch of each R, G, B fluorescent stripe is about 900 micrometers, respectively. FIG. 8A shows the luminance signal level when the red filter is attached to the optical system 5 and the R phosphor stripe is photographed by the line sensor camera 6. Therefore, the portion of the R phosphor stripe brightly emits light and is labeled "name". However, light emission from portions of the phosphor stripes of G and B is darkened and marked as "dark" because it is shielded by a red filter.

Next, the operation of the image processing unit 8 will be described with reference to FIG. 2. FIG. 2A shows the luminance signal level of, for example, an R phosphor stripe taken with a line sensor camera on line A as in FIG. 8A. 2B shows a randomly defined section Ta. This section Ta is for averaging the luminance signal level of the R phosphor stripe shown in Fig. 2A in order to detect the coating unevenness, so that the coating unevenness can be easily determined. Therefore, although the section Ta can be arbitrarily determined, in the present embodiment, the level detecting section 12 detects the peak of the luminance signal level of each phosphor stripe, that is, the luminance signal level of the R phosphor stripe, and the peak of this luminance signal level. And between the peaks (corresponding to about 900 µm). Further, in this section Ta, the luminance signal of the sensor of 18 pixels of the line sensor camera is output. In addition, the size of one pixel of the line sensor camera is about 50 µm.

Next, the averaging processing unit 13 averages the luminance signal levels in the section Ta. That is, the signal shown in FIG. 2A becomes a signal level (integrated value of the period Ta of a luminance signal) averaged for every area | region Ta as shown in FIG. 2C. As is apparent from Fig. 2C, the signal level obtained by averaging the luminance signal level is similar to that of Fig. 2A even though the luminance signal level is almost constant (representing a state in which the R phosphor stripe is applied almost uniformly), for example, L1, L2, It is fluctuating much like L3. This is because the light emitting area and the non-light emitting area (the partition part and the phosphor stripe part which is not actually detected as a signal by the line sensor camera because the light of the filter is different because the light is different from each other) are accumulated. Because it changes.

FIG. 2D shows a signal level obtained by averaging luminance signal levels equal to or greater than the threshold value TH shown in FIG. 2A. As is also apparent from this figure, the signal levels L4, L5 and L6 are at almost the same level. That is, the level difference does not occur when the light emitting portion enters two stripes of the phosphor and one stripe within the section Ta. Therefore, in the present invention, the output signal is not affected by the non-emission region by averaging the luminance signal level above the threshold TH among the luminance signal levels of the phosphor stripe 3 photographed by the line sensor camera 6 for each section Ta. Therefore, the moiré reduction described above is reduced. In addition, although the threshold value TH is set to about 70% of the maximum value of the luminance signal level, the luminance signal level also varies depending on the width of the phosphor stripe, the thickness of the coating film, and the like. Therefore, the threshold value TH may be determined experimentally. . In addition, as a method for averaging the luminance signal level equal to or greater than the threshold TH for each section Ta, the luminance signal level equal to or lower than the threshold TH is subtracted from the luminance signal level shown in FIG. It may be.

Although the ultraviolet light source 4 illuminates so that the whole line A on the glass substrate 1 shown in FIG. 6 may be included, the ultraviolet light source 4 also changes the amount of illumination light in the center part and the edge part. Therefore, it is said that the illumination unevenness of the ultraviolet light source 4 can be corrected by measuring the distribution of the illumination light in advance, obtaining a correction coefficient, and the like, and correcting it when calculating the average of the luminance values in the averaging processing unit 13. There is no need.

The coating spot detection unit 14 detects the level of the signal shown in FIG. 2D averaged by the averaging processing unit 13, and judges that the coating spot of the phosphor stripe is absent or acceptable if it is within a predetermined range, and determines the predetermined range. In the case of over, it judges that there is coating unevenness. For example, when applied to an actual product, when the average value level of the luminance signal in the case of being applied almost uniformly is 100%, the level of + 20% or more than this level, or -20% or less If there is more than one thing, it is judged that there is coating unevenness. In addition, this determination level is the worst level, needless to say that it can change suitably according to the kind of object product, the thinking method of a yield rate, etc. If it is determined that there is a coating unevenness, subsequent processing steps are stopped, the phosphor stripe is removed, and the process returns to the initial step of applying a new phosphor stripe. This can reduce, for example, defective products of the plasma display panel, and can also help to improve production efficiency.

In addition, although the above embodiment refers to the averaged level of the luminance signal in the section Ta, it is also possible to grasp the coating unevenness quantitatively for each phosphor stripe and to help improve the coating process of the phosphor stripe. This will be described below. The image processing unit 8 calculates the maximum luminance, the minimum luminance, the average value, the deviation, and the like from the luminance signal of the image input from the level detector 12, quantitatively detects the luminance unevenness according to the calculation result, and detects the detected luminance. The spot information is output to the display unit 9. That is, as shown in Fig. 8B, the light emission luminance level of the appropriate phosphor stripe (for example, the average value) is set to 100%, and the level of + 20% or more or the level of -20% or less of this level is defective. The emission level of the pixel is calculated, and the deviation of the emission level of each pixel is calculated based on the average value level. Such calculation is calculated for all the pixels of the glass substrate 2, and the position and number of both parts of all the pixels are recorded and managed from the determination results of the maximum value, the minimum value, the average value, and the deviation. This makes it possible to quantitatively evaluate the coating unevenness of the phosphor stripe of the plasma display panel, for example, to help improve the coating process.

As mentioned above, although this invention was demonstrated in detail, this invention is not limited to the Example of the fluorescent substance inspection method and fluorescent substance inspection apparatus described here, It can be widely adapted to the inspection method and inspection apparatus of what fluorescent substance etc. which were apply | coated other than the above were applied. Needless to say. That is, the phosphor may be complementary as well as the three primary colors. In addition, it is preferable that the light emission by these three kinds of phosphors maintains a good white balance, and that the afterglow after irradiation of electron emission light is also short for each of the three kinds of phosphors.

In addition, in the said Example, although the ultraviolet-ray was mentioned as the example of electron emission light, if it is the electron emission light which light-emits when irradiated to the fluorescent substance of object, it may be electromagnetic waves, particle beams, such as gamma rays and X-rays.

According to the present invention, the moiré phenomenon caused by the non-light-emitting part such as the partition wall can be eliminated, so that coating unevenness such as phosphor stripes can be detected appropriately, and inspection of defective products can be easily performed. In addition, it is possible to measure quantitatively, which can also help to improve the coating process of the phosphor stripe and the like. In addition, irradiated spots of ultraviolet light can be reduced, which is very effective for inspecting spots of coating of phosphor stripes such as plasma display panels.

Claims (10)

A plurality of stripe-shaped phosphors formed on a substrate are irradiated with electromagnetic waves or particle beams to photograph light emitted from the stripe-shaped phosphors, and a signal level of the photographed image is detected to detect a signal level above a predetermined value of the signal level. The average value of the part corresponded to is computed, and the application | coating spot of the said stripe fluorescent substance is detected based on the calculated average value, It is characterized by the above-mentioned. Phosphor screening method. The method of claim 1, The average value of the portion corresponding to the signal level equal to or greater than the predetermined value of the signal level is calculated for each predetermined section. Phosphor screening method. The method of claim 2, The plurality of stripe-shaped phosphors are at least one kind of phosphor stripe among R, G, and B phosphor stripe, and the predetermined section is substantially the same as the repetition period of the phosphor stripe. Phosphor screening method. The method of claim 2, Detecting a maximum value of a signal level equal to or greater than a predetermined value of the signal level, and making the predetermined interval between the maximum values. Phosphor screening method. The method of claim 1, wherein the maximum signal level, the minimum signal level, the average value, and the deviation are calculated from the signal level of the photographed image, and the coating spot of the phosphor stripe is detected based on the calculation result. . Phosphor inspection comprising an irradiation section for irradiating electromagnetic waves or particle beams to a plurality of stripe-shaped phosphors formed on a substrate, a photographing unit for photographing light emitted from the stripe-shaped phosphor, and an image processing unit for processing the photographed image signal In the apparatus, The photographing unit comprises a line sensor moving in the direction of the stripe, the image processing unit detects a signal level of the photographed image, and calculates an average value of a portion corresponding to a signal level of a predetermined value or more of the signal level, It has a function of detecting the coating unevenness of the said stripe-shaped fluorescent substance based on the calculated average value Phosphor inspection device. The method of claim 6, And the image processing unit is constituted by means for calculating an average value of portions corresponding to signal levels equal to or greater than a predetermined value of the signal level for each predetermined section of the image signal. Phosphor inspection device. The method of claim 7, wherein The plurality of stripe-shaped phosphors are at least one kind of phosphor stripe among R, G, and B phosphor stripes, and the image processing unit includes means for detecting the predetermined section that is substantially equal to a repetition period of the phosphor stripes. By Phosphor inspection device. The method of claim 7, wherein And the image processing unit has a level detection unit that detects a maximum value of a signal level equal to or greater than a predetermined value of the signal level and sets the maximum value to the predetermined section. Phosphor inspection device. The method of claim 6, The image processing unit has a level detection unit and a coating spot detection unit, the level detection unit calculates a maximum signal level, a minimum signal level, an average value and a deviation from the signal level of the photographed image, and the coating spot detection unit is based on the calculation result. Characterized by detecting the coating unevenness of the phosphor stripe Phosphor inspection device.