JP3678870B2 - Inspection apparatus and inspection method for slit type shadow mask - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inspection apparatus and inspection method for a slit-type shadow mask used for color selection of a color cathode ray tube (CRT), and more particularly to an inspection apparatus and method for extracting defects on a shadow mask surface portion.
[0002]
[Prior art]
The Sidoux mask used for color selection of a color cathode ray tube (CRT) has initially responded to the high resolution requirement by high-precision processing of the shadow mask itself. It is recognized that color misalignment due to thermal expansion due to electron beam when used for color selection in CRT) is not negligible, and low-expansion invar material is used as the shadow mask material, or the shadow mask is fixed to the frame At this time, a slit type that uses tension on the shadow mask has been adopted.
The slit-type shadow mask has a shape as shown in FIG. 10 and is manufactured by etching.
10A is a schematic diagram of the whole, FIG. 10B is an enlarged view of the dotted-line circle portion C0 in FIG. 10A, and FIG. 10C, FIG. 10 (c) and (b) are cross-sectional views taken along line C1-C2 of FIG. 10 (b), respectively.
In the case of the cross-sectional shape of the slit opening shown in FIGS. 10C and 10A, since the plate thickness is thin, it is penetrated by etching only from one side. In the case of FIGS. Is performed from both sides.
Then, as shown in FIG. 11, such a shadow mask is incorporated by fixing the shadow mask 860 to a color cathode ray tube (CRT) 800 to a frame 870.
A color cathode ray tube (CRT) 800 allows an electron beam 815 from an electron gun 810 to be scanned while being deflected and controlled by a deflection yoke 820 to pass through a slit portion of a shadow mask 860 and emit light to a fluorescent surface 850. The person in front of the panel 840 watches the light emitted from the fluorescent screen.
[0003]
As a method of fixing the slit type shadow mask with a frame for incorporation into a color cathode ray tube (CRT), a method using thermal expansion and a method using frame press are known.
The one using the thermal expansion is called Zenith FTM (Flat Tension Mask), and utilizing the difference in thermal expansion between the metal slit mask with a thickness of about 25 μm and the ceramic frame, It is assembled at high temperature and tension is applied as the metal shrinks at room temperature.
Also, the frame pressurization uses a slit-type shadow mask (also called aperture grill) with a thickness of about 100 μm, and is fitted with a frame with an R-face called Otaiko through the mask. The frame is rubbed (chucked) on the R surface, tension is applied, the frame is pressed after R molding by frame positioning, and the mask is welded and fixed to the pressurized frame It is.
[0004]
[Problems to be solved by the invention]
In these slit-type shadow masks, further improvement in quality and stabilization are desired, and as shown in FIG. 9, recess defects (scratch defects 211A, etc.) and slits on the surface of the grill 210 of the shadow mask 200 are shown. It has also become necessary to inspect defects at the boundary between the opening 220 and the grill 210 (such as a chip defect 215A, an egress defect 215B, and a large hole defect 215C).
FIGS. 9B, 9A, and 9B are cross-sectional views corresponding to F1-F2 and F3-F4 in FIG. 9A, respectively. FIGS. 9C and 9B and 9C and 9B are views showing a cross section of the defect portion.
On the other hand, as a conventional shadow mask inspection technique, an inspection method using transmitted light is known, as known in JP-A-6-160049, JP-A-6-2229737, JP-A-6-242014, and the like. However, it is difficult to apply these inspection methods when inspecting the shadow mask surface portion in the slit type shadow mask.
For this reason, in these slit type shadow masks, there has been a demand for an inspection apparatus capable of inspecting recess defects (scratch defects) in the surface portion of the shadow mask grill and defects at the boundary between the slit aperture and the grill. .
Under such circumstances, the present invention intends to provide an inspection apparatus and method for inspecting the state of the surface portion of a shadow mask of a slit type shadow mask having a slit opening penetrated by etching. It is.
[0005]
[Means for Solving the Problems]
The slit type shadow mask inspection apparatus of the present invention is a slit type shadow mask used for color selection of a color cathode ray tube having slit apertures, with the slit apertures directed and conveyed in a direction perpendicular to the conveyance direction. , An inspection apparatus for extracting the presence or absence of defects on the surface of the slit type shadow mask, Said A first linear light source that irradiates the front and back surfaces of the shadow mask, a second linear light source, and Said The first linear light source, Said Input the specular reflection light from the second linear light source, Said A first line sensor for obtaining an image data signal of the shadow mask surface; a second line sensor; Said First line sensor, Said An image data signal obtained by the second line sensor, and an image data processing unit for extracting the presence or absence of defects on the front and back surfaces; and Said In the shadow mask slit direction Said The first linear light source, Said A second linear light source, Said First line sensor, Said A second line sensor is provided, and the image data processing unit is Said First line sensor, Said Obtained by the second line sensor Said From the image data signal, Said The edge of the grill front surface was detected for each of the front and back surfaces of the shadow mask, and detected. Between adjacent edges on the same side, Surface width or Slit opening width To correspond to the number of pulses of a predetermined frequency, The Corresponding to the number of luth Said Shadow mask surface Said The width of the front and the back Said The width of the surface, or Said Corresponding to the number of pulses Said Shadow mask surface Said The width of the slit opening and the back Said A first comparison / determination unit that compares the width of the slit opening with the number of pulses, and determines that it is normal if the difference is a predetermined difference and abnormal if it is not the predetermined difference; Said Corresponding to the number of pulses Said Of the shadow mask surface, Adjoining said Surface width or Adjacent slit opening width A second comparison and determination unit that compares with the number of pulses, and determines that it is normal if it matches, and abnormal if it does not match, Said Corresponding to the number of pulses Said On the back of the shadow mask, Adjoining said Surface width or Adjacent slit opening width Compared with the number of pulses, normal if it matches, normal if it does not match, and abnormal only if all of the comparison and determination units are normal, It has a logic judgment part which judges other than abnormal.
And in the above, Said The first linear light source, Said The second linear light sources are arranged so that the light irradiation directions face each other.
[0006]
The slit type shadow mask inspection apparatus of the present invention is capable of extracting defects on the grill mask surface portion of the shadow mask in a state where the electrodeposition resist is embedded in the opening portion of the shadow mask. It is not necessary to embed, and can be applied to the extraction of defects on the grill mask surface portion of the shadow mask alone.
In some cases, the shadow mask slit opening portion may be embedded with an opaque electrodeposition resist or the like to detect defects on the surface of the shadow mask. It is not necessary to arrange the first linear light source and the second linear light source on the front and back of the shadow mask so that the light irradiation directions face each other.
[0007]
The slit type shadow mask inspection method of the present invention is a slit type shadow mask used for color selection of a color cathode ray tube (CRT) having slit apertures, and the slit apertures are directed in a direction perpendicular to the transport direction. An inspection method for extracting the presence or absence of defects on the surface of the slit-type shadow mask while transporting, Said The front and back of the shadow mask, Said Irradiated with the first linear light source and the second linear light source provided in the slit direction of the shadow mask, Said The first linear light source, Said The specularly reflected light from the second linear light source, respectively, Said By inputting with the first line sensor and the second line sensor provided in the slit direction of the shadow mask, Said Obtaining image data signals of the front and back surfaces of the shadow mask; Said First line sensor, Said From the image data signal obtained from the second line sensor, Said The edge of the front surface of the grille was detected for each of the front and back surfaces of the shadow mask, and detected. On the same side The width of the surface between adjacent edges or Slit opening width Corresponding to the number of pulses of a predetermined frequency, Said Corresponding to the number of pulses Said Shadow mask surface Said The width of the front and the back Said The width of the surface, or Said Corresponding to the number of pulses Said Shadow mask surface Said Slit opening width and back Of the above A first comparison and determination step of comparing the width of the lit opening with the number of pulses, and determining that it is normal if the difference is a predetermined difference and abnormal if it is not the predetermined difference; Said Corresponding to the number of pulses Said Of the shadow mask surface, Adjoining said Surface width or Adjacent slit opening width For the second comparison and determination step of comparing with the number of pulses, determining that it is normal if it matches, and abnormal if it does not match, Said Corresponding to the number of pulses Said On the back of the shadow mask, Adjoining said Surface width or Adjacent slit opening width And comparing with the corresponding number of pulses, respectively, and having a third comparison determination step for determining normality if they match, and determining abnormal if they do not match, and a first comparison determination step, It is characterized by determining whether the shadow mask surface is defective or not by determining whether it is normal or abnormal by logical operation determination of the results obtained by the second comparison determination step and the third comparison determination step. Is.
And in the above, Said The first linear light source, Said The second linear light sources are arranged so that the light irradiation directions face each other.
[0008]
[Action]
The slit type shadow mask inspection apparatus of the present invention is configured as described above, and inspects the state of the shadow mask surface portion of the slit type shadow mask having a slit aperture penetrated by etching. It is possible to provide a device.
Specifically, the first linear light source, the second linear light source that irradiates the front and back surfaces of the shadow mask, respectively, Said The first linear light source, Said Input the specular reflection light from the second linear light source, Said A first line sensor for obtaining an image data signal of the shadow mask surface; a second line sensor; Said First line sensor, Said An image data signal obtained by the second line sensor, and an image data processing unit for extracting the presence or absence of defects on the front and back surfaces; and Said In the shadow mask slit direction Said The first linear light source, Said A second linear light source, Said First line sensor, Said A second line sensor is provided, and the image data processing unit is Said First line sensor, Said Obtained by the second line sensor Said From the image data signal, Said The edge of the grill front surface was detected for each of the front and back surfaces of the shadow mask, and detected. Between adjacent edges on the same side, Surface width or Slit opening width To correspond to the number of pulses of a predetermined frequency, The Corresponding to the number of luth Said Shadow mask surface Said The width of the front and the back Said The width of the surface, or Said Corresponding to the number of pulses Said Shadow mask surface Said The width of the slit opening and the back Said A first comparison / determination unit that compares the width of the slit opening with the number of pulses, and determines that it is normal if the difference is a predetermined difference and abnormal if it is not the predetermined difference; Said Corresponding to the number of pulses Said Of the shadow mask surface, Adjoining said Surface width or Adjacent slit opening width A second comparison and determination unit that compares with the number of pulses, and determines that it is normal if it matches, and abnormal if it does not match, Said Corresponding to the number of pulses Said On the back of the shadow mask, Adjoining said Surface width or Adjacent slit opening width Compared with the number of pulses, normal if it matches, normal if it does not match, and abnormal only if all of the comparison and determination units are normal, This is achieved by having a logic determination unit that determines that other than that is abnormal.
That is, the slit-type shadow mask inspection apparatus according to the present invention includes a first comparison determination unit, a second comparison determination unit, a third comparison determination unit, and a logic determination unit, thereby providing a shadow mask front and back surface. Grill surface width or grill Slit opening width It is determined whether or not the difference is normal, and the width of the front surface portion of the adjacent grill on the front and back surfaces of the shadow mask, or the grill Slit opening width It is possible to detect defects reliably by determining whether or not the defect is normal and determining the final presence or absence of defects by the logical operation of these determinations.
Also, Said The first linear light source, Said Since the second linear light source is arranged so that the light irradiation directions face each other, the first line sensor and the second line sensor on the front and back are almost each Said The first linear light source, Said Light from only the second linear light source enters, and input of light from opposite sides of the shadow mask can be ignored.
[0009]
The slit type shadow mask inspection method of the present invention is configured as described above to ensure the presence or absence of defects on the surface of the shadow mask in the slit type shadow mask having slit apertures penetrated by etching. It is possible to extract to.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The slit type shadow mask inspection apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of the slit type shadow mask inspection apparatus of the present invention, FIG. 2 is a schematic plan view seen from the A0 side of FIG. 1, and FIG. 3 is a schematic configuration of the image processing data processing unit. FIG. 4 and FIG. 5 are diagrams for explaining the processing for making the edge signal width correspond to the number of pulses.
1, 2, 3, 4, and 5, 100 is an inspection device, 110 is a first linear light source, 115 is a second linear light source, 120 is a first line sensor, and 125 is a second Line sensor 127, ND filter, 150, image data processing unit, 200, shadow mask, 200A front surface, 200B back surface, 200S, shadow mask material, 210, grille, 211, surface portion, 211E, edge, 215, side wall portion , 220 are slit apertures, 311 and 312 are image data memories, 321 and 322 are comparison units (edge detection units), 325 is a slice level determination unit, 331 and 332 are rectangular wave generation units, 340 is a pulse generation unit, 351 , 352 is a counter, 361 is a first comparison / determination unit, 362 is a second comparison / determination unit, 363 is a third comparison / determination unit, 371 and 372 are memories, and 380 is a logic unit. Tough (OR circuit), a first line sensor image data signal 410, the second line sensor image data signals 415, 421 and 422 surface portion signal level, the 431 and 432 Slit opening Signal levels 441 and 442 are slice levels, 451 and 452 are edge portions, 410A, 411A, 415A, and 416A are generated waveforms, and 410B, 411B, 415B, and 416B are pulse displays.
The inspection apparatus of the present invention is a slit type shadow mask used for color selection of a color cathode ray tube (CRT) having a slit aperture penetrated by etching, and the slit aperture is directed in a direction perpendicular to the transport direction. This is an inspection apparatus that extracts defects on the surface portion of the shadow mask while being conveyed. As shown in FIG. 1, the first linear light source 110 and the second linear shape irradiate the front and back surfaces of the shadow mask 200, respectively. The first line sensor 120, the second line light source 115, the first line light source 110, the second line light source 110, and the first line sensor 120, the second line light source 115, respectively, are inputted to obtain the image data signal of the shadow mask 200 surface. The image data signals obtained by the line sensor 125, the first line sensor 120, and the second line sensor 125 are processed to extract the presence or absence of defects on the front and back surfaces. And an image data processing unit 150, and, as shown in FIG. 2, the second linear light source 115, the second line sensor 125 provided in the grille 210 direction of the shadow mask 200.
Of course, although not shown in FIG. 2, the first linear light source 110 and the first line sensor 120 are also provided in the direction of the grill 210 of the shadow mask 200. The first line sensor 120 and the second line sensor 125 in the apparatus shown in FIG. 1 are incorporated in a camera and are CCD elements or the like.
[0011]
In the inspection apparatus 100 shown in FIG. 1, the first linear light source 110 and the second linear light source 115 on the front and back of the shadow mask 200 are arranged so that the light irradiation directions face each other. This is because when a shadow mask alone or a shadow mask slit aperture 220 part with a transparent electrodeposition resist embedded in inspection light is inspected for defects on the front surface of the shadow mask, The line sensor 110 and the second line sensor 115 may be configured such that no light is input from the opposite side of the shadow mask.
FIG. 1 shows a diagram of extracting defects on the surface of the grill 210 in a state where the electrodeposition resist 250 is embedded in the slit opening 220 of the shadow mask 200. It is not necessary to embed the electrodeposition resist 250, and the inspection apparatus 100 can be applied also when extracting defects on the grill surface portion with a shadow mask alone.
In the case of inspecting a surface portion for a shadow mask in which an opaque electrodeposition resist is embedded in inspection light, as shown in FIG. The linear light source 115, the first line sensor 120, and the second line sensor 125 may be arranged.
[0012]
The image data processing unit 150 detects the edge 211E of the front surface portion 211 of the grill 210 from the front and back surfaces of the shadow mask 200 from the image data signals obtained by the first line sensor 120 and the second line sensor 125, respectively. And the width of the surface portion 211 between the detected edges or Slit opening width Corresponds to the number of pulses of a predetermined frequency.
And the width of the front surface portion 211 of the grille between the edges of the shadow mask front and back surfaces corresponding to the number of pulses or Slit opening width Are compared with the number of pulses, and if the difference is within a predetermined difference, the first comparison / determination unit (361 in FIG. 3) determines that the difference is normal, and if not, the shadow corresponding to the number of pulses is determined. The width between adjacent edges of the mask surface is compared by the number of pulses, and if they match, the second comparison / determination unit (362 in FIG. 3) determines that it is normal, and if they do not match, the number of pulses 3 is compared by the number of pulses for the width between adjacent edges on the back surface of the shadow mask, and a third comparison determination unit (363 in FIG. ), And a logic determination unit (380 in FIG. 3) that determines that the determination is normal only when all of the comparison determination units are normal and determines that the other is abnormal.
[0013]
Next, the processing flow of the image data processing unit 150 will be described with reference to FIG.
S31 to S36 and S31A to S36A indicate each step.
First, the image data signal 120D obtained by the first line sensor 210 on the surface 200A side of the shadow mask shown in FIG. 1 is sequentially associated with each pixel position of the line sensor and the number of scans. Only a few scans are stored in the image data memory 310. (S31)
Next, for each data at each position in the image data memory 310, the comparison unit (edge detection unit) 321 compares the data with a predetermined slice level to obtain the edge position of the surface portion. (S32) The slice level setting unit 325 sets the slice level in the comparison unit (edge detection unit) 321.
From the obtained edge position, a rectangular wave is generated by the rectangular wave generating unit 331, and the width of the surface portion of the shadow mask grill or Slit opening width A rectangular wave output corresponding to is obtained. (S33)
This allows the width of the surface between adjacent edges or Slit opening width Is detected.
Then, the width of the surface portion between the detected edges or Slit opening width Is made to correspond to the number of pulses of a predetermined frequency, and this number of pulses is obtained by a counter. (S34)
The width of the surface portion between the pulse from the pulse generator 340 having a predetermined frequency and the detected adjacent edge or Slit opening width The width of the surface portion between the detected edges or the AND output with the square wave corresponding to Slit opening width The number of pulses corresponding to can be obtained.
[0014]
Similarly, the image data signal 125D obtained by the second line sensor 125 on the surface 200B side of the shadow mask shown in FIG. 1 is also detected through the processing of S31A, S32A, S33A, and S34A. The width of the surface between edges or Slit opening width Corresponds to the number of pulses of a predetermined frequency.
[0015]
Next, the width of the surface portion between the front and back edges, obtained corresponding to the number of pulses, or Slit opening width Are compared with the number of pulses by the first comparison / determination unit 361. If the difference between the two is within a predetermined number, it is determined as normal, and the other is determined as abnormal. (S35) When it is determined to be normal, 0 is output and this is input to the logic determination unit (OR circuit unit) 370.
If it is determined that there is an abnormality, one output is output and this is input to the logic determination unit (OR circuit unit) 380.
[0016]
In this way, the width of the surface portion between adjacent edges in turn or Slit opening width On the other hand, the number of pulses in the counter 351 corresponding to the width between adjacent edges is stored in the memory 371, and the pulses stored in the memory 371 are stored. The number and the newly obtained pulse number in the counter 351 are compared by the second comparison / determination unit 362, and when they match, it is determined as normal, and when they do not match, they are determined as abnormal. (S36)
If it is determined to be normal, 0 is output, and this is input to the logic determination unit (OR circuit unit) 380, respectively. If it is determined that there is an abnormality, one output is output and each is input to a logic determination unit (OR circuit unit) 380. Similarly, the number of pulses in the counter 352 corresponding to the width between adjacent edges is stored in the memory 372, the number of pulses stored in the memory 372, and then the newly obtained counter 352 Are compared by the third comparison / determination unit 363, and the case where they match is determined to be normal, and the case where they do not match is determined to be abnormal. (S36A)
If it is determined to be normal, 0 is output, and this is input to the logic determination unit (OR circuit unit) 380, respectively. If it is determined that there is an abnormality, one output is output and each is input to a logic determination unit (OR circuit unit) 380.
In this way, the second comparison determination unit 362 and the third comparison determination unit 363 sequentially compare the numbers of pulses obtained by the counters 351 and 352 in the order obtained, thereby obtaining the adjacent surface portions. Width or Slit opening width In Abnormal Check if there is or not.
[0017]
The logic determination unit (OR circuit unit) 380 receives and outputs inputs from the first comparison determination unit 361, the second comparison determination unit 362, and the third comparison determination unit 363, and all inputs are 0. If it is (normal determination), it is determined to be normal and 0 is output, and if one of the inputs is 1 (abnormal determination), it is determined to be abnormal and 1 is output.
[0018]
Next, data processing will be further described for the image data signals in steps S32 to S34 and S32A to S34A.
The data processing shown in FIG. 4 obtains the number of pulses corresponding to the width of the surface portion based on the image data signal 410 from the first line sensor 125 and the image data signal 415 from the second line sensor 120. It is processing.
For simplicity, the case where there is no defect on the surface portion will be described.
4 (a), (b), (b), (b), and (c), (b) show the first line sensor for the surface portion of the shadow mask surface (200A side in FIG. 1). 4 (a), (b), FIG. 4 (b), (b), and FIG. 4 (c) (b) show the back side of the shadow mask (FIG. 1). The processing transition of the image data signal 415 obtained from the second line sensor 120 is shown for the surface portion on the (200B side).
FIG. 4A shows a comparison between the image data signal and a predetermined slice level 441 (442). By the comparison, the position of the edge 451 (452) of the surface portion is detected, and based on the detection result of the edge position. A rectangular wave as shown in FIG. 4B is generated.
In the rectangular wave shown in FIG. 4B, the position of the edge in which the image data signal in FIG. 4A cuts the slice level from the bottom to the top is the rising edge of the rectangular wave, and the edge position that cuts from the top to the bottom Is the falling edge of the rectangular wave.
By generating a rectangular wave by edge detection of the image data signal shown in FIG. 4A, an output corresponding to the width of the surface portion of the grill shown in FIG. 4B is obtained.
The number of pulses corresponding to the width of the surface portion can be obtained by taking an AND output of the output corresponding to the width of the surface portion shown in FIG. 4B and the output from the pulse generation portion of a predetermined frequency. Can do. (Fig. 4 (c))
[0019]
The data processing shown in FIG. 5 is the same as that in FIG. 4, based on the image data signal 410 (415) obtained from the line sensor, between adjacent edges. Slit opening width The number of pulses corresponding to is obtained and compared.
For simplicity, only the process transition of the image data signal 410 obtained from the first line sensor 125 on the surface of the shadow mask (200A side in FIG. 1) will be described first.
5A and 5A show a comparison between the image data signal 410 by the first line sensor 125 and a predetermined slice level 441A, and the position of the edge 451A of the surface portion is detected by the comparison, and the edge A rectangular wave 411A as shown in FIGS. 5A and 5B is generated based on the position detection result.
In the rectangular wave 411A shown in FIGS. 5A and 5B, the edge position where the image data signal 410 in FIG. 5A and FIG. 5A cuts the slice level 441A from the top to the bottom is the rising edge of the rectangular wave. The position of the edge that cuts from bottom to top is the falling edge of the rectangular wave.
In this way, by generating a rectangular wave by edge detection of the image data signal shown in FIGS. 5A and 5A, the shadow mask grille shown in FIGS. Slit opening width Get the output corresponding to.
As shown in FIG. Slit opening width 5 and the output from the pulse generator of a predetermined frequency, the number of pulses corresponding to the width of the surface portion can be obtained.
Similarly, with respect to the processing transition of the image data signal 415 obtained from the second line sensor 115 on the back surface of the shadow mask (200B side in FIG. 1), edge detection by comparison (FIGS. 5A and 5B). ), As shown in FIG. Slit opening width To get a square wave corresponding to Slit opening width The number of pulses corresponding to is obtained. (Fig. 5 (c) (b))
[0020]
Next, the process of S32 to S34 (S32A to 34A) shown in FIG. 3 will be briefly described with reference to FIG.
FIG. 5 shows a waveform when there is no defect in the surface portion of the grill. Slit opening 9A and 9B, when the image data signal is captured by the line sensor at the position having the scratch defect 211A shown in FIG. 9, the image data signal 410 and the predetermined slice level 441A by the line sensor are shown in FIGS. It becomes like this.
Then, by comparing the image data signal 610 with a predetermined slice level 641, the position of the edge 651 of the surface portion is detected, and by edge detection, Slit opening width When a rectangular wave output corresponding to is generated, the result is as shown in FIG.
Scratch defects are detected at the edge.
Further, the obtained results are shown in FIGS. Slit opening width And an AND output of the output from the pulse generator with a predetermined frequency, Slit opening width The number of pulses corresponding to can be obtained. (Fig. 6 (a) (c))
That is, Slit opening In FIG. 9, the abnormal pulse P <b> 1 is counted at the spot having the scratch defect 211 </ b> A.
So adjacent Slit opening In comparison, at the location where the abnormal pulse occurred due to the defective location, Slit opening There is a large difference from the number of pulses corresponding to, so that a defect can be detected.
[0021]
Also, Slit opening When the image data signal is captured by the line sensor at the location having the defect 215A shown in FIG. 9, the image data signal 610A by the line sensor and the predetermined slice level 641A are shown in FIGS. It becomes like this.
Then, by comparing the image data signal 610A with a predetermined slice level 641A, the position of the edge 651A of the surface portion is detected, and by edge detection, Slit opening width When a rectangular wave output corresponding to is generated, the result is as shown in FIG.
Edge detection is performed on a defective spot.
Further, the obtained results are shown in FIGS. Slit opening width And an AND output of the output from the pulse generator with a predetermined frequency, Slit opening width The number of pulses corresponding to can be obtained. (Fig. 6 (b) (c))
That is, Slit opening For the part having the chip defect 215A shown in FIG. Slit opening It will be counted more than.
This is normal Slit opening There is a difference in the number of pulses.
In addition, for a portion having the chip defect 215A shown in FIG. 9 only on the front and back surfaces, the difference in the number of pulses between the front and back surfaces exceeds a predetermined number.
Therefore, the defective part can be recognized.
[0022]
Next, the relationship between the state in which the electrodeposition resist is embedded in the slit opening of the shadow mask and the image data signal obtained from the line sensor will be described below with reference to FIG.
The electrodeposition resist is provided for inspection with the shadow mask grille fixed.
FIG. 7A shows the state of the shadow mask shown in FIG. 1 in a state where the electrodeposition resist 250 is embedded in the slit opening 220 with both surfaces thereof substantially parallel to the shadow mask surface, as described above. The image data signals obtained from the line sensor are as shown in FIGS.
FIG. 7B shows a case where the electrodeposition resist 250 has a concave shape recessed from the shadow mask surface. In this case, image data signals obtained from the front and back of the shadow mask are shown in FIG. 7B and FIG. FIG. 7B and FIG.
FIG. 7C shows a case where the electrodeposition resist protrudes in a convex shape from the shadow mask surface. This case is also almost the same as the concave shape.
[0023]
【The invention's effect】
As described above, the present invention makes it possible to provide an inspection apparatus for extracting defects on the surface portion of a slit-type shadow mask having slit openings that are penetrated by etching.
As a result, in such a slit type shadow mask, further improvement in quality and stabilization can be expected.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a slit type shadow mask inspection apparatus according to the present invention.
FIG. 2 is a diagram showing the positional relationship between a shadow mask, a linear light source, and a line sensor.
FIG. 3 is a diagram for explaining data processing;
FIG. 4 is a diagram for explaining processing for making the edge signal width correspond to the number of pulses;
FIG. 5 is a diagram for explaining processing for making the edge signal width correspond to the number of pulses;
FIG. 6 is a diagram for explaining processing of an image data signal in which a defective portion is taken in
FIG. 7 is a diagram for explaining an image data signal when an electrodeposition resist is embedded in a slit opening;
FIG. 8 is a diagram showing an example of the positional relationship between a linear light source and a line sensor.
FIG. 9 is a diagram for explaining a surface defect of a shadow mask.
FIG. 10 is a diagram for explaining a slit-type shadow mask;
FIG. 11 is a diagram for explaining a color cathode ray tube (CRT);
[Explanation of symbols]
100 inspection equipment
110 First linear light source
115 Second linear light source
120 First line sensor
125 Second line sensor
127 ND filter
150 Image data processor
200 shadow mask
200A surface
200B reverse side
200S shadow mask material
210 Grill
211 Surface
211 Scratch defect
211E edge (edge of surface)
215 Side wall
215A chip defect
215B Aegle defect
215C large hole defect
220 slit opening
250 Electrodeposition resist
311 and 312 Image data memory
321, 322 Comparison unit (edge detection unit)
325 Slice level judgment unit
331, 332 Rectangular wave generator
340 pulse generator
351, 352 counter
361: First comparison determination unit
362 Second comparison / determination unit
363 Third comparison judgment unit
371, 372 memory
380 Logic determination unit (OR circuit unit)
410 First line sensor image data signal
410A, 415A rectangular wave
410B, 415B Pulse display
411A, 416A rectangular wave
411B, 416B Pulse display
412 Image data signal on the surface
415 Second line sensor image data signal
417 Image data signal on back side
421, 422 Surface level signal level
431, 432 Slit opening Signal level
441, 441A, 442, 442A Slice level
451, 451A, 452, 452A Edge
700 Shadow Mask
710 Grill
715 slit
720 peripheral area
722 notch
730 Opening area
800 color cathode ray tube (CRT)
810 electron gun
815 electron beam
820 Deflection yoke
830 Funnel
840 panels
850 Fluorescent surface
860 Shadow Mask
870 frames

Claims (4)

The slit type shadow mask used for color selection of the color cathode ray tube having the slit aperture has a surface defect of the slit type shadow mask while the slit aperture is directed and conveyed in the direction orthogonal to the conveyance direction. an inspection apparatus for extracting a first linear light source to the front and back surfaces of the shadow mask, irradiated respectively, a second linear light source, the first linear light source, the second linear light source the regular reflection light from each type, the first line sensor to obtain an image data signal of the shadow mask surface, a second line sensor, the first line sensor, obtained by the second line sensor the image data signal to the data processing was, and an image data processing unit that extracts the presence or absence of a defect in the front and back surfaces, and the first linear light source in the slit direction of the shadow mask It said second linear light source, the first line sensor, in which is provided the second line sensor, the image data processing unit, said first line sensor, obtained by the second line sensor from the image data signals which are the respective the front and back surfaces of the shadow mask, to detect the edge of the grill surface portion, and the detected between adjacent edges on the same side, the width of the width or slit opening on the surface portion and it made to correspond to the number of pulses of a predetermined frequency, the width of said surface portion of the corresponding to the pulse number the shadow mask surface and a width of the back surface of said surface portion, or, corresponding to the number of the pulse the width of the slit aperture of the shadow mask surface is, the width of the back surface of the slit opening, compared with a pulse number, normally if a predetermined difference, if not a predetermined difference different The first comparison determination part, has been the shadow mask surface corresponds to the number of said pulses to determine that, the width of the slit opening to the width or adjacent the surface portion adjacent, and compared with a number of pulses, matches normal if, a second comparison determination unit that determines an abnormality if they do not match, the said shadow mask backside which is corresponding to the number of pulses of the slit opening to the width or adjacent the surface portion adjacent the width Compared with the number of pulses, normal if it matches, normal if it does not match, and abnormal only if all of the comparison and determination units are normal, A slit-type shadow mask inspection apparatus, comprising: a logic determination unit that determines that other than that is abnormal. According to claim 1, wherein the first linear light source, said a second linear light sources, each other light irradiation direction is the shadow mask inspection apparatus of the slit type which is characterized in that it is arranged to face. A slit type shadow mask used for color selection of a color cathode ray tube (CRT) having slit apertures is directed to the surface of the slit type shadow mask while the slit apertures are directed and conveyed in a direction perpendicular to the conveyance direction. an inspection method for extracting the presence or absence of a defect, the front and back surfaces of the shadow mask, respectively, the provided slit direction of the shadow mask, the first linear light source, and irradiated with a second linear light source, It said first linear light source, the specular reflection light from the second linear light source, respectively, each of the al slit-direction of the shadow mask first line sensor, by inputting the second line sensor a step of obtaining image data signals of the front and back surfaces of the shadow mask, the first line sensor, the image data obtained from said second line sensor From JP, respectively, for the front and back surfaces of the shadow mask, to detect the edge of the surface portion of the grill, and the widths or slit opening on the surface portion between the edges adjacent to the same side that has been detected, the predetermined frequency a step to correspond to the number of pulses, the width of said surface portion of the shadow mask surface, which is corresponding to the number of the pulses, the width of the back surface of said surface portion, or, the shadow mask surface, which is corresponding to the number of the pulse the width of the slit opening, and a width of the back surface of said slits opening, compared with a pulse number, normally, if not a predetermined difference first comparison that determines that the abnormality determination if a predetermined difference steps and the shadow mask surface, which is corresponding to the number of the pulse, the width of the slit opening to the width or adjacent the surface portion adjacent, compared with a pulse number, match Normal, a second comparison determination step of determining a matching abnormally unless, of said shadow mask backside which is corresponding to the number of the pulse, the width of the slit opening to the width or adjacent the surface portion of the adjacent, respectively And comparing with the corresponding number of pulses, and having a third comparison judgment step for judging normal if they match, and judging abnormal if they do not match, and a first comparison judgment step and a second comparison A slit type characterized in that it is determined whether it is normal or abnormal by the logical operation determination of the result obtained by the determination step and the third comparison determination step, and the presence or absence of defects on the shadow mask surface is extracted. Shadow mask inspection method. According to claim 3, wherein the first linear light source, said a second linear light sources, shadow mask inspection method of a slit type which is characterized in that it is arranged so that the irradiation direction of light face each other.

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