JP2007279047A - Optical inspection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect an inspection-desired defective to enhance the inspection reliability, by receiving, from an imaging device, only a light component of bringing a defective shape into relief through a feature on a surface of an inspection object, in the defective, out of the light components incident multi-angularly. <P>SOLUTION: This optical inspection system, for inspecting optically the surface of the inspection object, includes a camera for imaging the surface of the inspection object, at least two illuminations for emitting a light to an imaging region of the inspection object imaged by the camera, and a shielding member for shielding the non-perpendicular light to prevent the perpendicular light reflected from the imaging region so as to be incident perpendicularly to the camera from colliding with the nonperpendicular light emitted from the at least two illuminations. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an optical inspection system, and more particularly to an inspection system that inspects the appearance of an inspection object such as a printed circuit board using an optical method.

Recently, a printed circuit board, which is one of the main materials used in various semiconductor integrated circuits such as driving integrated circuits (LCD Driver ICs), memories and LSIs for liquid crystal display devices, and ultra-compact products, also includes films and tapes. And is manufactured.

In such a printed circuit board, a circuit generally called a TAB (Tape Automatic Bonding) or COF (Chip On Film) board is widely used. A printed circuit board in the form of a film or tape is formed by a manufacturing process such as exposure or development, and such a pattern is miniaturized as a semiconductor device is gradually miniaturized, and the pattern is formed through the human eye. In fact, it is becoming increasingly impossible to inspect the defects. Therefore, it has become necessary to introduce an optical inspection system in order to accurately and quickly detect a printed circuit board, which is a raw material for forming a pattern, and a defect in a pattern formed on the printed circuit board.

In general, an optical inspection system performs an optical inspection using a camera, an image sensor, etc. At this time, an automatic optical inspection system uses various illumination devices to reveal defects in the appearance of the printed circuit board. Carry out accurate inspection. In that case, which lighting device to select from among various lighting devices is an important issue for accurate defect detection. In particular, the coaxial epi-illumination has been used for inspecting a product whose surface reflects light like a mirror, such as a driving integrated circuit COF of a liquid crystal display device.

However, the optical inspection system 1 using coaxial incident illumination has the following problems. As shown in FIG. 6, it has the reflective mirror 3 which refracts the light which injects from the side surface of the coaxial epi-illumination 2 toward the test object 10 (printed circuit board), and this reflective mirror 3 inspects the light of the illumination 2 In the process of refracting the object 10, a light amount loss of light occurs. Further, since the imaging device 8 (LINE CCD SENSOR through the lens) sees an image through the reflecting mirror 3 of the coaxial incident illumination 2, a refraction phenomenon by the reflecting mirror 3 occurs and a defocusing phenomenon occurs.
JP 2006-17726 A

An object of the present invention is to receive only a light component in which a defective shape is highlighted through a feature on the surface of an inspection object from among components of light incident from multiple angles, and receive a desired defect inspection. To provide an optical inspection system with improved inspection reliability.

Another object of the present invention is to provide an optical inspection system having an illumination device capable of obtaining a clear image.

Another object of the present invention is to provide an optical inspection system in which a defective shape on the surface of an inspection object is raised to enhance inspection reliability.

According to one embodiment of the present invention for achieving the above object, an optical inspection system for optically inspecting the surface of an inspection object includes a camera for imaging the surface of the inspection object, and an inspection imaged by the camera. At least two illuminations that irradiate light onto the imaging area of the object and vertical light that is reflected from the imaging area and perpendicularly incident on the camera does not collide with non-vertical light that is emitted from the at least two illuminations And a blocking member that blocks non-vertical light and reflects some non-vertical light into a vertical component.

In a preferred embodiment of the present invention, the at least two illuminations are less than the first angle of the main illumination and the main illumination installed to irradiate the imaging area surface of the inspection object with light at the first angle. Auxiliary illumination installed to irradiate light at an inclination angle may be included.

In a preferred embodiment of the present invention, the main illumination is disposed at a position closer to the imaging area than the auxiliary illumination, and the heights of the main illumination and the auxiliary illumination are sequentially reduced as the distance from the imaging area increases.

In a preferred embodiment of the present invention, the blocking member may include a path through which vertical light passes and a blocking plate positioned between at least two lights, and the blocking plate is irradiated from at least two lights. An outer surface that guides the imaging area to be irradiated with light.

In a preferred embodiment of the present invention, the shielding plate has an outer surface that is guided so that light emitted from the auxiliary illumination is irradiated to the imaging region, and the outer surface of the shielding plate is a reflecting surface.

In a preferred embodiment of the present invention, the outer surface of the blocking plate can be tilted so that the imaging area is directed.

In a preferred embodiment of the present invention, the blocking member may further include a hinge part installed on the blocking plate so as to adjust an angle of light guided to the imaging region along the outer surface of the blocking plate.

In a preferred embodiment of the present invention, the blocking member is installed on the blocking plate, and further includes a support plate on which the main illumination and the auxiliary illumination are installed on the bottom surface.

In a preferred embodiment of the present invention, the support plate is rotatably installed to adjust the irradiation angle between the main illumination and the auxiliary illumination.

In a preferred embodiment of the present invention, the main illumination and the auxiliary illumination are rotatably installed on the bottom surface of the support plate (so as to adjust the irradiation angle).

In a preferred embodiment of the present invention, it is preferable that the first angle of the main illumination and the angle formed between the outer surface of the blocking plate and the surface of the imaging region are 75 ° or more and 90 ° or less.

According to another embodiment of the present invention for achieving the above object, an optical inspection system for optically inspecting the surface of an inspection object is imaged by a camera for imaging the surface of the inspection object, and the camera. A blocking member that divides the vertical region so that only vertical light is incident on the camera among the illumination that irradiates the imaging region of the inspection object and the light that irradiates and reflects the imaging region of the inspection object Including.

In a preferred embodiment of the present invention, the blocking member includes an outer area where illumination is located and the illumination area is irradiated with the illumination light, and a blocking plate for partitioning the vertical area.

In a preferred embodiment of the present invention, the shielding plate includes an outer surface formed of a reflecting surface, and the outer surface of the shielding plate is light emitted from the illumination, and the light irradiated on the outer surface of the shielding plate is the imaging region. Tilt to be guided by.

In a preferred embodiment of the present invention, the illumination is located closest to the imaging area of the inspection object, and the main illumination illuminates the imaging area at a first angle, and an inclination smaller than the first angle of the main illumination. And auxiliary illumination that irradiates the imaging region with light at an angle.

As described above, the present invention can increase the reliability of the inspection when inspecting the defective shape of the surface of the inspection object. The present invention not only minimizes the light loss of light, but also adjusts the angle of the blocking member to adjust the light component (angle) required for inspecting various defective shapes on the surface of the inspection object. Component of light obtained by changing). The present invention is very useful for inspecting a COF substrate among substrates in the form of films and tapes.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described here, and may be embodied in other embodiments. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the spirit of the invention to those skilled in the art. Accordingly, element shapes and the like in the drawings may be exaggerated to emphasize a clearer description.

Embodiments of the present invention will be described in detail with reference to FIGS. In the drawings, the same reference numerals are assigned to components having the same function.

The basic intention of the present invention is that accurate and vivid imaging is possible by irradiating the surface of an inspection object (printed circuit board such as a COF board) whose surface reflects light like a mirror with uniform light. Is to provide a simple optical inspection system. For this purpose, the present invention is characterized in that it has a blocking member that blocks vertical light provided to the camera from colliding with other light out of light reflected from the imaging region of the inspection object. is there.

FIG. 1 is a configuration diagram of an optical inspection system according to the present invention, and FIG. 2 is a diagram for schematically explaining a light path in the optical inspection system of the present invention.

Referring to FIGS. 1 and 2, the optical inspection system 100 includes a camera 110 for imaging the surface of the inspection object 10, an illumination 120, and a blocking member 130. The blocking member 130 and the illumination 120 may be formed as one module.

The camera 110 is arranged so as to be separated from the upper part of the imaging region 10a of the inspection object 10. A blocking member 130 and an illumination 120 are disposed on one side under the camera 110. Here, the camera 110 is for capturing an image of the imaging region 10a of the inspection object, and an image sensor (CCD or CMOS), an optical system (lens), or the like is usually used and provided from the camera 110. The video signal is provided to the video processing device 180. The image processing apparatus 180 includes a typical computer system, and controls and processes all operations by automatic optical inspection. The video processing device 180 determines the presence or absence of a defect on the surface of the inspection object using the video signal provided from the camera 110.

The blocking member 130 protects the vertical light L1 so that the vertical light L1 reflected from the imaging region 10a and perpendicularly incident on the camera 110 does not collide with non-vertical light emitted from the illumination 120. The blocking member 130 includes a support plate 132 on which the illumination 120 is installed on the bottom surface, and a blocking plate 134 for dividing the outer region a and the vertical region b, which are symmetrical to each other about the vertical region b. Or may be installed only on one side. It is desirable that the illumination 120 be installed only on any one support plate 132. The support plate 132 has a bottom surface 132a inclined downward on the outer shell, and the illumination 120 is installed on the inclined bottom surface 132a at different heights to prevent light interference between the illuminations 120. For example, the installation angle (irradiation angle) can be adjusted passively or automatically by installing the illumination device 120 rotatably on the hinge portion of the bracket 133.

Here, the outer region a is a space where the illumination 120 installed on the support plate 132 is located, and at the same time, the light of the illumination 120 is provided to the imaging region 10a of the inspection object 10, and the vertical region b is an image. It can be said that only the vertical light L1 out of the light reflected from the region 10a is incident on the camera 110.

The blocking plate 134 protects the vertical light L1 so that the vertical light L1 that is reflected from the imaging region 10a and is incident on the camera 110 perpendicularly does not collide with other non-vertical light L2. Have In addition, the blocking plate 134 also has a function to guide (guide) the direction of the light so that the non-perpendicular light L2 emitted from the illumination 120 is irradiated with the imaging region 10a. For this purpose, the blocking plate 134 has an outer surface 135 made of a reflective surface that can reflect the light emitted from the illumination 120 and provide the direction to the imaging region 10a. That is, the outer side surface 135 guides the imaging region to be irradiated with non-perpendicular light deviated from the imaging region 10a among the light irradiated from the illumination 120. The outer side surface 135 is inclined so as to face the imaging region 10a, and the inclination angle X1 is preferably 75 ° or more and 90 ° (an angle close to vertical) or less from the surface of the imaging region 10a.

As shown in FIG. 3, the blocking plate 134 is rotatably installed on the hinge portion 139 of the support plate 132, and the inclination angle of the outer surface 135 can be adjusted. The direction of the light L3 can be adjusted.

On the other hand, in the present embodiment, the inner surface 136 of the blocking plate 134 is shown to have the same inclination angle as the outer surface 135, but the blocking plate 134 is parallel to the vertical light L1 as shown in FIG. 136 may be included.

FIG. 4 is a view showing an example in which a rotatable blocking member is provided in the optical inspection system according to the embodiment of the present invention. As shown in FIG. 4, the blocking member 130 can rotate around the hinge shaft 138, and the rotation angle of the blocking member 130 simultaneously changes the installation angle of the illumination 120 and the inclination angle of the outer surface 135 of the blocking plate 134. Can be adjusted.

The outer surface 135 of the blocking plate 134 is preferably made of a material (such as stainless steel) that is coated (coated) with a reflective paint for reflecting light, is attached with a reflective sheet, or is sufficiently reflective. Further, the outer surface 135 may be formed with a negative or positive pattern so that light is reflected and provided to the imaging region 10a.

Referring back to FIGS. 1 and 2, the illumination 120 includes four illuminations 122, 124 a, 124 b, and 124 c that irradiate light in the imaging region 10 a of the inspection object 10 imaged by the camera 110. The illumination 120 can be divided into one main illumination 122 and three auxiliary illuminations 124a, 124b, 124c. The main illumination 122 and the three auxiliary illuminations 124a, 124b, and 124c are rotatably installed on the bottom surface 132a of the support plate 132 of the blocking member 130 in order to change the irradiation angle. In the present embodiment, the illuminations 122, 124a, 124b, and 24c use light emitting diodes (LEDs) having a projection angle of 20 ° to 30 ° (an angle at which light spreads). A light source may be used. Moreover, although four illuminations were used in this embodiment, this is only one embodiment.

The main illumination 122 is an illumination that directly irradiates the surface of the imaging region 10a of the inspection object, and the main illumination 122 has a first installation angle that is not less than 75 ° and not more than 90 ° (an angle close to vertical) from the surface of the imaging region 10a. Installed to have X2. Of course, the main illumination 122 may provide the indirect light L3 that is irradiated on the outer surface 135 of the blocking plate according to the installation angle and then reflected and indirectly irradiated onto the imaging region 10a. However, the amount of indirect light is relatively small compared to auxiliary lighting. The first, second, and third auxiliary lights 124a, 124b, and 124c are more than the main light 122 so that the indirect light L3 that is indirectly irradiated is larger than the light that is directly irradiated to the surface of the imaging region 10a of the inspection object. Is installed with a large inclination. As shown in FIG. 1, the installation angle of the main illumination 122 and the installation angles of the first, second, and third auxiliary illuminations 124a, 124b, and 124c are the main illumination installation angle X2> the first auxiliary illumination installation angle X3. > Installation angle X4 of second auxiliary illumination> Installation angle X5 of third auxiliary illumination.

In the optical inspection system 100 configured as described above, the path of illumination light is as follows. First, light emitted from the main illumination 122 is applied to the imaging region 10a at an angle close to vertical, and among the light reflected from the imaging region 10a, the vertical light L1 enters the camera 110 through the vertical region a. At this time, if there is a concave portion (not shown) on the surface of the imaging region 10a, the light irradiated to the concave portion does not reflect vertically, so that portion looks dark. Therefore, if the image picked up by the camera 110 is viewed, the defect detection is very easy because the concave portion is dark. A part of the light emitted from the auxiliary illuminations 124a, 124b, and 124c can be applied to the imaging region 10a, but most of the light is applied to the outer surface 135 (reflection surface) of the blocking plate 134. The non-vertical light L2 irradiated on the outer surface 135 of the blocking plate 134 is guided along the outer surface 135 and indirectly provided to the imaging region 10a with indirect light L3 that is nearly vertical. At this time, the indirect light L3 irradiated and reflected on the outer surface 135 becomes uniform throughout the reflection process, and is provided as light that increases the amount of light in the imaging region 10a. If the light emitted from the auxiliary lights 124a, 124b, and 124c is directly applied to the surface of the imaging region 10a, the portion appears bright due to light scattering inside the concave portion of the surface, and the defective position is determined. There is a risk of problems disappearing. Therefore, in the present invention, in order to prevent such undetected portions of the concave portions, the illumination angles (installation angles) of the auxiliary illuminations 124a, 124b, and 124c are inclined to reduce the light directly irradiated on the imaging region 10a to the maximum extent, On the other hand, in order to increase the amount of light incident on the camera 110, indirect light L3 is provided to the imaging region 10a.

The optical inspection system 100 according to the present invention can be very useful for inspecting a COF substrate among substrates in the form of a film or a tape. For example, the COF substrate has a highly reflective surface such as a mirror. Only when the incident angle of light illuminating the inspection object on the COF substrate is irradiated perpendicularly to the camera, the light is transmitted to the image sensor of the camera, and a vivid image can be obtained. That is, in the optical inspection system 100 of the present invention, the light L1 reflected vertically from the imaging region 10a of the inspection object 10 can enter the camera 110 without colliding with other light, and the non-vertical light L2 is imaged. By changing the direction of the non-vertical light L2 and irradiating it so that indirect illumination close to vertical is supplied to the region 10a, it is possible not only to minimize the light amount loss of light but also to obtain a vivid image. it can.

The above detailed description illustrates the invention. Also, the foregoing is merely illustrative of a preferred embodiment of the present invention, and the present invention can be used in various other combinations, modifications, and environments. Further, changes or modifications can be made within the scope of the concept of the invention disclosed in the present specification, the scope equivalent to the above-described disclosure, and / or the technical knowledge of those skilled in the art. The above-described embodiments are for explaining the best state for carrying out the present invention, and other states known to those skilled in the art can be used to utilize other inventions such as the present invention. Various modifications required for implementation and specific application fields and uses of the invention are also possible. Accordingly, the above detailed description of the invention is not intended to limit the invention to the disclosed embodiments. Also, the appended claims should be construed to include other implementations.

It is a block diagram of the optical inspection system by this invention. It is a figure for demonstrating schematically the path | route of the light in the optical inspection system of this invention. It is a figure for demonstrating the shielding board which can rotate in the optical inspection system of this invention. It is a figure which shows the example provided with the interruption | blocking member which can be rotated in the optical inspection system of this invention. It is a figure which shows the example with which the shielding board which has an inner surface perpendicular | vertical to the optical inspection system of this invention was comprised. It is a schematic block diagram of the optical inspection system using the conventional coaxial epi-illumination.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inspection object 10a Imaging area 100 Optical inspection system 110 Camera 120 Illumination 122 Main illumination 130 Blocking member 132 Support plate 133 Bracket 134 Blocking plate 135 Outer side surface 180 Image processing apparatus

Claims (17)

In an optical inspection system that optically inspects the surface of an inspection object,
A camera that images the surface of the inspection object;
At least two illuminations for irradiating light to an imaging region of the inspection object imaged by the camera;
And a blocking member that blocks the non-perpendicular light so that the vertical light reflected from the imaging region and perpendicularly incident on the camera does not collide with non-vertical light emitted from the at least two illuminations. A featured optical inspection system. The at least two lights are:
Main illumination installed to irradiate light at a first angle on the surface of the imaging region of the inspection object;
The optical inspection system according to claim 1, further comprising at least one auxiliary illumination installed to irradiate light at an inclination angle smaller than a first angle of the main illumination. There are a plurality of auxiliary lights,
The main illumination is arranged closer to the imaging area than the auxiliary illumination,
The optical inspection system according to claim 2, wherein the main illumination and the auxiliary illumination are sequentially lowered in height as they are farther from the imaging region. The blocking member is
The optical inspection system according to claim 1, further comprising a path through which the vertical light passes and a blocking plate positioned between the at least two illuminations. The blocking plate has an outer surface that is guided so that the non-perpendicular light shifted from the imaging region is irradiated to the imaging region among the light emitted from the at least two illuminations. The optical inspection system according to claim 4. The blocking member includes a blocking plate positioned between a path through which the vertical light passes and the at least two lights,
The said shielding board has an outer surface guided so that the said non-perpendicular light which shifted | deviated from the said imaging area among the lights irradiated from the said at least 1 auxiliary illumination may be irradiated to the said imaging area. Item 3. The optical inspection system according to Item 2. The optical inspection system according to claim 6, wherein an outer surface of the blocking plate is a reflective surface. The optical inspection system according to claim 6, wherein an outer surface of the blocking plate is inclined to face the imaging region. The blocking member is
The optical inspection system according to claim 6, further comprising a hinge portion installed on the shielding plate so as to adjust an angle of light guided to the imaging region along an outer surface of the shielding plate. The blocking member is
The optical inspection system according to claim 6, further comprising a support plate installed on the blocking plate and having the main illumination and the auxiliary illumination installed on a bottom surface. The optical inspection system according to claim 10, wherein the support plate is rotatably installed so as to adjust an irradiation angle between the main illumination and the auxiliary illumination. The optical inspection system according to claim 10, wherein the main illumination and the auxiliary illumination are rotatably installed on a bottom surface of the support plate. 9. The optical system according to claim 8, wherein the first angle of the main illumination and the angle formed by the outer surface of the blocking plate and the surface of the imaging region are both 75 ° or more and 90 ° or less. Inspection system. In an optical inspection system that optically inspects the surface of an inspection object,
A camera that images the surface of the inspection object;
Illumination for irradiating light to an imaging region of the inspection object imaged by the camera;
An optical inspection system comprising: a blocking member that divides the vertical region so that vertical light among the light irradiated and reflected on the imaging region of the inspection object is incident on the camera. The blocking member includes an outer region in which the illumination is located and light of the illumination is irradiated onto an imaging region of the inspection object, and a blocking plate for partitioning the vertical region. 14. The optical inspection system according to 14. The blocking plate includes an outer surface made of a reflective surface,
The outer surface of the shielding plate is inclined so that light emitted from the illumination to the outer surface of the shielding plate is guided to the imaging region. The optical inspection system described. The lighting is
Main illumination that is closest to the imaging area of the inspection object and that irradiates the imaging area with light at a first angle;
The optical inspection system according to claim 15, further comprising auxiliary illumination that irradiates the imaging region with light at an inclination angle smaller than a first angle of the main illumination.

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