JP2002014058A - Method and apparatus for checking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for checking capable of uniformly illuminating a image pickup range, when picking up image and checking a stereoscopic pattern to be checked by a one-dimensional CCD image pickup element and obtaining a proper image of the pattern to be checked on a work. SOLUTION: In the method for checking, by combining line illuminating means 11 to 14 from four directions in the photographing range 5 in the work 1 and illuminating the work 1 so that the intensity of the light input to the one-dimensional CCD 3 of the light diffused in the pattern to be checked on the work 1 becomes uniform, the proper image of the stereoscopic pattern to be checked is made obtainable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a case of inspecting a three-dimensional pattern such as a sealing material for liquid crystal in a liquid crystal panel, and a method of inspecting a flat object to be inspected such as glass. The present invention relates to an inspection method and apparatus effective for inspecting whether there is any abnormality in the inspection.

[0002]

2. Description of the Related Art Conventionally, when inspecting a pattern formed on a flat work surface such as glass using a material which easily diffuses incident light three-dimensionally, as shown in FIG. And a method of irradiating light from an oblique direction.

In FIG. 7, reference numeral 21 denotes a work on which a sealing material pattern 21b to be inspected is formed on a glass plate 21a. A recognition camera 22 includes a one-dimensional image sensor such as a one-dimensional CCD 23 and an imaging lens system 24. 25
Is an imaging range of the one-dimensional CCD 23.
5, ring illumination means 26 is provided, and an imaging range 2
5 is configured to be illuminated from all directions. 27
Is a receiving surface that supports the work 21. Then, the imaging range 25 is illuminated by the ring illuminating means 26 and the one-dimensional CC
The image is captured at D23, and the sealing material pattern 21b is inspected by image processing.

According to such an inspection method, the work 21
The light irradiated to the background portion other than the sealing material pattern 21b is specularly reflected on the surface of the work 21, and the specularly reflected light 30 does not enter the one-dimensional CCD 23, and the light incident on the sealing material pattern 21b is Diffuse and the diffused light 29 is one-dimensional CC
Since the light is incident on D23, an image in which the brightness is increased only in the sealing material pattern 21b by the one-dimensional CCD 23 is obtained.
When the illumination is performed from one direction, the sealing material pattern 2
Since 1b is three-dimensional, a portion that is not irradiated with light appears as a shadow. However, since light is irradiated from all directions, luminance can be obtained regardless of the direction of the sealing material pattern 21b.

[0005]

However, the above conventional configuration has the following problems.

1) When an inspection is performed with the imaging range 25 of the work 21 widened, as shown in FIG. 8, regular reflection light 30 of the illumination light 28 from the ring illumination means 26 on the surface of the work 21 is converted to a one-dimensional CCD 23. And the image is captured in a state where the luminance of the portion without the sealing material pattern 21b is high, and the imaging range 25 is smaller than the size of the ring illuminating means 26.

2) The distance between the sealing material pattern 21b and the illumination is different, and depending on the location, the deviation of the angle of the illuminated light becomes large. Therefore, the brightness of the image of the sealing material pattern 21b by the one-dimensional CCD 23 varies depending on the location. May be different. Referring to FIG. 9, FIG. 9A shows a state where the work 21 is viewed from the recognition camera 22 side.
(B) shows the image pattern at that time, and the image pattern 31 of the sealing material pattern 21b at the center of the imaging range 25 is shown.
Although the illumination from all directions is almost uniformly emitted, an appropriate image pattern having a uniform luminance distribution is obtained, but the image pattern 32 of the sealing material pattern 21b at the end of the imaging range 25 is obtained.
Is large because the component of light emitted from left to right is large.
2a is an image pattern in which the luminance is higher than the right 32b.

3) Illumination light 2 from ring illumination means 26
As shown in FIG. 10A, the light 8 is diffused on the receiving surface 27 through the glass plate 21a, and is imaged in a state where the luminance of the portion without the sealing material pattern 21b is high due to the influence of the diffused light 33. Will be. On the other hand, as shown in FIG. 10B, measures such as attaching an anti-reflection material 34 on the receiving surface 27 may be taken. However, as shown in FIG. After inspecting the work 21 by supporting the work 21 on the anti-reflection material 34 stuck on 27, FIG.
As shown in (b), when the work 21 is detached, peeling electrification may occur on the work 21 and may cause a problem. For example, when the work 21 is made of quartz glass and the antireflection material 34 is made of polyphenol, the charge amount due to the peeling charge increases.

4) When the metal pattern 21c having a high reflectance is printed on the transparent glass plate 21a as shown in FIG. 12, the sealing material pattern 21b in the transparent portion The illumination light 28 applied to the pattern portion is diffused, and one-dimensional CC of the diffused light 29 is diffused.
While only the direction component toward D23 enters the one-dimensional CCD 23, the sealing material pattern 21b formed on the metal pattern 21c additionally includes a transparent glass plate 2b.
In the portion 1a, the diffused light 29 that has escaped downward is also reflected by the metal pattern 21c and enters the one-dimensional CCD 23. Therefore, when the surface state of the work 21 varies depending on the location, the sealing material pattern 21b may have a different luminance depending on the location. Are captured in different states.

The present invention has been made in consideration of the above-described conventional problems, and can provide an appropriate image of an inspection target on a work by uniformly illuminating an imaging range, and can also diffuse light on a work receiving surface. It is an object of the present invention to provide an inspection method and apparatus capable of preventing occurrence of influence and peeling electrification when the work is removed from a receiving surface, and capable of obtaining an appropriate image of an inspection object even when the work surface has a reflective surface. And

[0011]

According to the inspection method of the present invention, when a three-dimensional object to be inspected on a work surface is imaged and inspected by a one-dimensional image sensor through an imaging lens system, the inspection is performed by the one-dimensional image sensor. 4 with line illumination for line-shaped imaging range
Since illumination is performed evenly from the direction, and the three-dimensional inspection object in the linear imaging range is uniformly illuminated from four directions, the light intensity diffused by the inspection object and input to the image sensor is made uniform. Thus, an image of an appropriate inspection object can be obtained, and an accurate inspection can be performed.

Further, when a space is formed between the work and its receiving surface, it is possible to reduce the incidence of diffused light on the receiving surface to the one-dimensional image pickup device when the work is light-transmitting. Scattered light can enter the one-dimensional imaging device, so that an appropriate image of the object to be inspected can be obtained, and due to the space between the work and the receiving surface, separation charging occurs when the work is removed. It is not affected by charging.

[0013] Further, the work surface has a reflection surface on a part thereof,
When a part of the inspection target is formed on its reflective surface, the receiving surface of the work is subjected to mirror finishing, and if a telecentric lens is used for the imaging lens system, diffused light on the receiving surface is eliminated, and the inspection target image is removed. The difference in contrast due to the difference in the surface state can be reduced, and the specularly reflected light outside the imaging range is prevented from entering the one-dimensional imaging device, so that an appropriate image can be obtained.

The above-described inspection method can be preferably applied to inspection of a sealing material pattern of liquid crystal, and can also be applied to inspection of foreign substances and scratches on a glass surface.

Further, the inspection apparatus according to the present invention is an inspection apparatus for inspecting a three-dimensional inspection object on a work surface by imaging with a one-dimensional imaging element through an imaging lens system. Four line illuminating means for uniformly illuminating the imaging range from each of the four directions are provided. As described above, it is possible to diffuse the light in the inspection target and make the light intensity input to the one-dimensional imaging element uniform. As a result, an appropriate inspection target image is obtained, and an accurate inspection can be performed.

Further, if the work is configured to be provided with a space between the work and its receiving surface to support the work, an appropriate image to be inspected can be obtained even when the work is light transmissive as described above.
In addition, there is no occurrence of peeling charging when the work is removed, and there is no adverse effect due to charging.

Further, when the receiving surface of the work is formed as a mirror surface and a telecentric lens is used for the imaging lens system, the work surface has a reflecting surface as described above,
Even when a part of the inspection target is formed on the reflection surface, a contrast difference due to a difference in surface state of the inspection target image can be reduced, and specularly reflected light outside the imaging range enters the imaging element. And a proper image can be obtained.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the inspection method and apparatus of the present invention are applied to inspection of a sealing material pattern of a liquid crystal will be described below with reference to FIGS.

In FIG. 1, a one-dimensional C, which is a one-dimensional image pickup device, is provided above a work 1 supported on a receiving surface 10.
A recognition camera 2 having a CD 3 and an imaging lens system 4 is provided, and line illuminating means 11 for irradiating illumination light from four directions to a linear imaging range 5 by a one-dimensional CCD 3 on four sides of the recognition camera 2. To 14 are provided. As shown in FIG. 2, the work 1 has a sealing material pattern 7 to be inspected applied on a liquid crystal color filter 6 and before the sealing material pattern 7 is applied to the color filter 6. The metal pattern 8 is formed in the sealing material pattern 7 not only in the portion where the metal pattern 8 does not exist,
It is also applied to existing parts.

The arrangement and configuration of the line illuminators 11 to 14 will be described in detail.
The line illuminators 11 to 14 are arranged in parallel with the three-dimensional CCD 3, and are configured to illuminate the linear imaging range 5 linearly. That is, the line illuminating means 11 and 12 are arranged on both sides on the extension of the one-dimensional CCD 3, and the line illuminating means 13 and 14 are arranged such that their centers are located on a plane passing through the center of the one-dimensional CCD 3 and intersecting vertically, In addition, the line illumination means 11 and 12, 13 and 14 are arranged so as to be equidistant about the center point of the one-dimensional CCD 3. The line illuminating units 11 and 12 are arranged outside the hatched area in FIG. 1B so that the specular reflected light of the illuminating light does not enter the one-dimensional CCD 3.

The line illuminating means 11 to 14 are arranged at an angle such that the central axis of the illuminating light of the line illuminating means 11 to 14 intersects a point where the center axis 9 of the imaging lens system 4 and the workpiece 1 intersect. Have been. Line illumination means 13, 14
Is equal in distance to imaging range 5 over the entire length,
The total light amount is made equal. On the other hand, line lighting means 1
In Nos. 1 and 12, the distance from the imaging range 5 varies depending on the location, and even if a condensing lens is used for line illumination, the light does not become completely parallel light but diffuses. 11a, 12a to correct this
The light intensity distribution is provided so that the light intensity increases from a to 11b and 12b. By doing so, the imaging range 5
Are illuminated with uniform illuminance, and the one-dimensional CCD 3 obtains a uniform image with uniform luminance over the entirety.

Next, a second embodiment of the present invention will be described.
This will be described with reference to FIG.

In FIG. 3, a spacer (not shown) is interposed in a portion of the lower surface of the work 1 where an object may come into contact, and a space 15 is provided between the work 1 and its receiving surface 10. In the case where the work 1 is bent, it is necessary to make the depth of field of the imaging lens system 4 sufficiently large to absorb the bending.

By doing so, when the work 1 is removed, it is possible to prevent the separation charge between the work 1 and the receiving surface 10. Further, when the distance between the work 1 and the receiving surface 10 can be made sufficiently large, the irradiation light to the receiving surface 10 by the illumination is not applied to the imaged portion as shown in FIG. Since the scattered light entering the three-dimensional CCD 3 on the receiving surface 10 is also reduced, it is not necessary to provide an anti-reflection material on the receiving surface 10. Thus, receiving surface 10
The effect of the scattered light at the point can be eliminated.

Next, a third embodiment of the present invention will be described.
This will be described with reference to FIGS. The basic configuration is the same as that of the second embodiment, and only different points will be described.

In FIG. 4, in the present embodiment, the receiving surface 10
Is a mirror surface receiving surface 16 which has been subjected to mirror surface processing. As a result, even in a portion where the metal pattern 8 is not printed below the sealing material pattern 7, a part of the scattered light 17 that has escaped downward is reflected by the mirror-finished processing receiving surface 16, and Irradiation light 18 not directly illuminated
Is also reflected by the mirror-finished processing receiving surface 16 and irradiates the sealing material pattern 7 from below. Therefore, even in the encapsulant pattern 7 on which the metal pattern 8 is not printed below, the same brightness as the portion where the metal pattern 8 is printed can be obtained.

However, as shown in FIG. 5A, a part of the scattered light 17 that has escaped downward from the sealing material pattern 7 is reflected by the mirror-finished receiving surface 16 and goes in the direction of the one-dimensional CCD 3. As shown in FIG. 5B, a ghost pattern 19 may appear on the side of the regular pattern 20 in the captured image, so that the imaging lens system 4 is a telecentric optical system and only emits light parallel to the optical axis. It is configured to be incident on the one-dimensional CCD 3. By doing so, it is possible to prevent the luminance from being different depending on the presence or absence of the metal pattern 8 and to reduce the scattered light on the receiving surface 10. When the material of the work 1 is glass, the receiving surface 1
For example, stainless steel, aluminum, or the like can be used for 0, and thereby, no peeling charging occurs.

In the above embodiment, an example in which the sealing material pattern of the liquid crystal is inspected has been described. However, the present invention is similarly applied to the case of detecting foreign matter, projections, scratches, etc. on a glass substrate. can do. At that time, when detecting a directional flaw or foreign matter, in the conventional example, as shown in FIG. 6A, when the illumination light in one direction is strong as shown by an arrow, an accurate shape and size are obtained. However, in the present invention, a case where detection is not possible may occur, but in the present invention, as shown in FIG.
Since the illumination is performed uniformly from the direction, it is possible to detect the area corresponding to the accurate shape and the actual size.

[0029]

According to the inspection method and apparatus of the present invention, when a three-dimensional inspection object on a work surface is imaged and inspected by a one-dimensional imaging device via an imaging lens system as described above,
Since the line illumination is evenly illuminated from four directions with respect to the linear imaging range of the one-dimensional imaging device,
A three-dimensional inspection object in a line-shaped imaging range is evenly illuminated from four directions, the light intensity diffused by the inspection object and input to the image sensor can be made uniform, and an appropriate image of the inspection object can be obtained. And accurate inspection can be performed.

Further, when a space is formed between the work and its receiving surface, it is possible to reduce the diffusion light on the receiving surface from entering the image pickup device when the work is light-transmitting, and it is possible to reduce the scattering mainly at the inspection object. Since light can enter the image sensor, an appropriate inspection target image can be obtained, and peeling charging does not occur when removing the work due to the presence of a space between the work and the receiving surface, It is not adversely affected by charging.

Further, the workpiece has a reflection surface on a part of the surface thereof,
When a part of the inspection target is formed on its reflective surface, the receiving surface of the work is subjected to mirror finishing, and if a telecentric lens is used for the imaging lens system, diffused light on the receiving surface is eliminated, and the inspection target image is removed. The difference in contrast due to the difference in the surface state can be reduced, and specularly reflected light outside the imaging range is prevented from entering the imaging device, so that an appropriate image can be obtained.

[Brief description of the drawings]

FIG. 1 shows a schematic configuration of a first embodiment of an inspection apparatus of the present invention, wherein (a) is a plan view, (b) is a view taken along the line AA of (a), and (c) is (a). FIG.

FIG. 2 is a partially enlarged cross-sectional view of a work according to the embodiment.

FIG. 3 shows a schematic configuration of a second embodiment of the inspection apparatus of the present invention, where (a) is a front view and (b) is a side view.

FIG. 4 is a partially enlarged front view of a main part of a third embodiment of the inspection apparatus of the present invention.

FIG. 5 shows problems to be solved in the embodiment;
(A) is a partial enlarged front view of a main part, and (b) is an explanatory view of an imaging screen thereof.

6A and 6B show an example in which the present invention is applied to another inspection object. FIG. 6A shows a defect to be detected in a conventional example and a captured image thereof, and FIG. 6B shows a defect to be detected in the present invention. It is an explanatory view showing the captured image.

FIG. 7 is a front view showing a schematic configuration of a conventional inspection apparatus.

FIG. 8 is a front view showing a problem when the inspection range is widened in the conventional example.

9A and 9B show a problem in the conventional example, in which FIG. 9A is a plan view, and FIG. 9B is a plan view of the imaging screen.

10A and 10B are a front view showing a state of scattered light on a receiving surface, and FIG.
(B) is a front view of the state where scattered light was eliminated by the antireflection material.

11A and 11B show a problem in the case where an anti-reflection material is provided in a conventional example, where FIG. 11A is a longitudinal sectional front view showing a support state of a work, and FIG. 11B is a longitudinal sectional front view showing a state where a work is removed. It is.

FIG. 12 is an enlarged vertical sectional front view of a main part of a work showing a problem in a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 work 3 one-dimensional CCD (one-dimensional image sensor) 4 imaging lens system 7 sealing material pattern (pattern to be inspected) 8 metal pattern 10 receiving surface 11 to 14 line illumination means 15 space 16 mirror processing receiving surface

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Noriaki Yukawa, Inventor No. 1006 Kadoma, Kadoma, Osaka Prefecture F-term (reference) 2G051 AA73 AB07 BA02 BB02 CA03 CB01 CC09 2G086 EE10

Claims (8)

[Claims] When a three-dimensional inspection object on a work surface is imaged and inspected by a one-dimensional imaging device via an imaging lens system, a line illumination is applied to a line-shaped imaging range of the one-dimensional imaging device. Inspection method characterized by uniformly illuminating from four directions. 2. The inspection method according to claim 1, wherein a space is formed between the work and its receiving surface. 3. When a part of the surface of the work has a reflection surface and a part of the inspection object is formed on the reflection surface, the work receiving surface is mirror-finished and the imaging lens system is telecentric. The inspection method according to claim 1, wherein a lens is used. 4. An inspection method for inspecting a sealing material pattern of a liquid crystal using the method according to claim 1. 5. An inspection method using the method according to any one of claims 1 to 3 for inspecting foreign matter and flaws on a glass surface. 6. An inspection apparatus for inspecting a three-dimensional inspection object on a work surface by imaging with a one-dimensional imaging device via an imaging lens system in four directions with respect to a linear imaging range of the one-dimensional imaging device. An inspection apparatus characterized in that four line illumination means for uniformly illuminating each of the lines are provided. 7. The inspection apparatus according to claim 6, wherein a space is provided between the work and its receiving surface to support the work. 8. The inspection apparatus according to claim 6, wherein the receiving surface of the work is formed as a mirror surface, and a telecentric lens is used for the imaging lens system.