JP2008286796A - Optical inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical inspection device, preventing a distortion phenomenon due to bending or sagging of an object to be inspected. <P>SOLUTION: This optical inspection device includes: a stage on which an object to be inspected is placed; a photographing unit for photographing the object to be inspected placed on the stage; an illuminating unit for radiating light to the object to be inspected; and a rolling member for supporting the edge of a region photographed by the photographing unit to maintain the flatness of the photographing region. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical inspection apparatus for a printed circuit board, and more specifically, images a pattern formed on an inspection object (printed circuit board), processes the captured image information, and forms an inspection object. The present invention relates to an optical inspection apparatus for inspecting a formed pattern for defects.

  Various types of printed circuit boards have been changed from existing rigid printed circuit boards to flexible printed circuit boards so that the line width of circuit boards can be further reduced by recent reductions in the thickness and size of electronic products, and can be applied to various forms of products. It is changing rapidly. Therefore, as the line width becomes smaller, inspection with the naked eye becomes increasingly difficult, resulting in a problem of reduced productivity, and the introduction of an automatic optical inspection system to overcome this problem becomes essential.

  In other words, in the pre-shipment inspection performed at a printed circuit board production company, the effects of appearance inspection items such as a plating area of a product, a solder resist area, an area where a semiconductor wafer is mounted (inner lead), etc. A fast and accurate inspection is at the heart of productivity and quality control. In particular, when inspecting a large glass substrate (circuit board), it is important to maintain flatness for stable inspection.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an optical inspection apparatus capable of stably inspecting a circuit board.

  An object of the present invention is to provide an optical inspection apparatus capable of inspecting while maintaining the flatness of a circuit board.

  An object of the present invention is to provide an optical inspection apparatus capable of inspecting a circuit board using transmitted light and reflected light.

  In order to achieve the above object, an optical inspection apparatus of the present invention includes a stage on which an inspection object is placed, an imaging unit for photographing the inspection object placed on the stage, and light on the inspection object. An illumination unit for irradiating and a rolling member for supporting the edge of the area imaged by the imaging unit to maintain the flatness of the imaging area.

  According to an embodiment of the present invention, the rolling member is a ball caster having a ball in rolling contact with the inspection object.

  According to an embodiment of the present invention, the optical inspection apparatus further includes a linear movement unit that moves the stage in the front-rear direction so that the imaging unit continuously images the inspection object.

  According to an embodiment of the present invention, the photographing unit includes a line scan camera for photographing by a line scan method, and the rolling member supports both ends of the photographing region photographed by the line scan camera. To do.

According to an embodiment of the present invention, the photographing unit includes an area camera for photographing by an area scan method, and the rolling member supports a corner of the photographing region photographed by the area camera.
According to an embodiment of the present invention, the illumination unit includes at least one of transmitted illumination that irradiates the inspection object with transmitted light and reflected illumination that irradiates the inspection object with reflected light.

  According to an embodiment of the present invention, the stage supports the left and right edges of the inspection object, and the space opened in the front-rear movement direction so that the rolling member is located under the inspection object. Have.

  According to an embodiment of the present invention, the stage is provided on a body having a space opened in a front-rear movement direction so that the rolling member is positioned under the inspection object, and an upper stage of the body, And a supporter that supports the left and right edges of the inspection object.

  According to an embodiment of the present invention, the stage further includes a position determining member that aligns the position of the inspection object placed on the supporter.

  According to an embodiment of the present invention, the optical inspection apparatus further includes a horizontal support that is provided horizontally in the front-rear movement direction of the stage, passes through an open space of the stage, and is provided with the rolling member. .

  In order to achieve the above object, an optical inspection apparatus of the present invention includes a stage on which an inspection object is placed, an imaging unit for photographing the inspection object placed on the stage, and light emitted from the inspection object. The stage includes a rolling member that is in rolling contact with the inspection object in order to maintain the flatness of the inspection object.

  According to an embodiment of the present invention, the rolling member includes a plurality of balls that support the imaging region edge of the inspection object imaged by the imaging unit at predetermined intervals.

  According to an embodiment of the present invention, the optical inspection apparatus further includes a linear moving unit that moves the stage together with the rolling member to an imaging region of the imaging unit so that the imaging unit continuously images the inspection object. Including.

  According to an embodiment of the present invention, the illumination unit includes transmitted illumination that irradiates the inspection object with transmitted light and reflected illumination that irradiates the inspection object with reflected light.

  According to the present invention, it is possible to prevent a distortion phenomenon caused by bending and bending (sagging) of an inspection object with respect to an imaging region.

  According to the present invention, an image having a stable focus can be obtained.

  According to the present invention, it is possible to inspect while maintaining the flatness of the inspection object.

  According to the present invention, higher inspection quality can be obtained for an inspection object.

  The embodiment of the present invention can be modified in various forms, and the scope of the present invention should not be construed to be limited by the embodiment described below. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Accordingly, the shapes of elements in the drawings are exaggerated for a clearer description.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying FIGS. In the drawings, the same reference numerals are assigned to components performing the same function.

The inspection apparatus of the present invention is suitable for inspection of a large circuit board. In particular, it is suitable for inspection of a large circuit board in which bending due to its own weight occurs and it is difficult to maintain flatness. The object to be inspected may be a circuit board in which glass is adhered and reinforced on the bottom surface, a glass board on which a circuit pattern is formed, or a wide circuit board (first embodiment).
FIG. 1 is a front view for explaining the configuration of the optical inspection apparatus according to the first embodiment of the present invention, and FIG. 2 is for explaining the configuration of the optical inspection apparatus according to the first embodiment of the present invention. FIG.

  1 and 2, the optical inspection apparatus 10 of the present invention includes a stage 100, a linear movement unit 200, an imaging unit 300, an illumination unit 400, and a rolling member 500.

(stage)
Stage 100 includes a body 110 having a bottom surface 112, a first side surface 114, and a second side surface 116. A supporter 120 and a position determining member 130 are provided on the upper stage of the body 110, that is, on the upper stage of the first and second side surfaces 114 and 116. The inspection object S is placed with both side edges supported by the supporter 120. The position determining member 130 is a cylinder for aligning both sides of the inspection object S placed on the supporter 120 and pressurizes both side surfaces of the inspection object S to correct (align) the left and right positions. A space is provided between the first and second side surfaces 114 and 116 of the body 110, and the space is opened in the upper part and the front-rear direction.

  The stage 100 is moved in the front-rear direction on the base plate 20 by the linear movement unit 200. The linear movement unit 200 includes an LM guide 210 and a linear motor 220. The stage 100 is guided by an LM guide 210 provided on the base plate 20, and moves in the front-rear direction by driving the linear motor 220. In the present embodiment, the linear movement unit 200 is shown and described as including the LM guide 210 and the linear motor 220. Can be applied.

(Shooting unit)
The imaging unit 300 is a CCD camera having an image sensor such as a CCD line sensor and a lens (not shown), and images the surface (pattern, etc.) of the inspection object S to acquire video data for the inspection object S. . The video data acquired as described above is provided to a video processing unit (not shown). Although not shown, the optical inspection apparatus 10 includes a video processing unit to which an image photographed from the photographing unit 300 is provided. The video processing unit is configured by a typical computer system (commonly known as a microcomputer), and controls and processes various operations associated with automatic optical inspection. For example, a line scan camera can be used as the imaging unit 300, and a line scan camera or an area camera can be additionally provided depending on the inspection conditions of the inspection object and user requirements. The photographing unit 300 is provided on the vertical frame 30 so as to be movable in the left-right direction. The guide rail 32 provided on the vertical frame 30 is provided with a moving plate 34, and the moving plate 34 is provided with a line scan camera which is an imaging unit 300. That is, the position of the photographing unit 300 can be adjusted to the left and right according to the region to be photographed.

(Lighting unit)
The illumination unit 400 includes a transmissive illumination 410 that irradiates the inspection object S with transmitted light, and a reflected illumination 420 that irradiates the inspection object S with reflected light. The reflected illumination 420 is disposed above the inspection object S, and the transmitted illumination 410 is disposed below the imaging region of the inspection object S. The transmitted illumination 410 and the reflected illumination 420 output light for acquiring video data for the imaging region of the inspection object S. For the light sources of the transmitted illumination 410 and the reflected illumination 420, a large number of light emitting diodes arranged in a linear arrangement, a linear tube fluorescent lamp, a halogen, a metal halide, and the like can be used. A diffusion plate or the like for improving the uniformity of light may be provided on the light source. The reflected illumination 420 is provided on the moving plate 34, and the transmitted illumination 410 is fixedly installed on the horizontal support base 600. The transmitted illumination 410 and the reflected illumination 420 can be adjusted in height.

(Rolling material)
The rolling member 500 which is the most important component in the present invention is for minimizing a distortion phenomenon caused by bending or bending (sagging) of the imaging region of the inspection object S, and the imaging region W of the inspection object S. A ball caster having a ball 510 in direct contact with the edge of the ball. The rolling member 500 is provided on the horizontal support base 600 so as to be positioned below the photographing unit 300. When the stage 100 is positioned below the imaging unit 300 for inspection, the rolling member 500 is positioned above the pair of vertical bases 520 so that the rolling member 500 is positioned at a height that allows rolling contact with the bottom surface of the inspection object S. To position. The pair of bases 520 are preferably provided on the horizontal support base 600 so that the height can be adjusted in order to adjust the height of the rolling member 500. As shown in FIG. 2, the transmitted illumination 410 is positioned between the pair of tables 520, and the horizontal support table 600 is positioned below the transmitted illumination 410.

(Horizontal support)
The horizontal support base 600 is a structure that is fixed so that the rolling member 500 and the transmitted illumination 410 are positioned in an open space of the stage 100 that moves in the front-rear direction. The horizontal support base 600 is positioned horizontally in the front-rear movement direction of the stage 100 and across the open space of the stage 100, and is provided on a fixed base 610 provided on both ends of the base plate 20. The horizontal support base 600 is provided with a rolling member 500 and a transmission illumination 410.

  FIG. 3 is a diagram illustrating a state in which the pair of rolling members 500 support both ends of the imaging region W. As shown in FIG. 3, since the imaging unit 300 is a camera that captures an image by the line scan method, the pair of rolling members 500 support the bottom surface of the inspection object S corresponding to both ends of the imaging region W by rolling contact. The unit 300 continuously photographs the inspection object S moving in the arrow direction (front-rear direction). In this case, photographing by the photographing unit 300 is performed in a state where the flatness is maintained by the pair of rolling members 500. Although only a pair of rolling members is shown in the embodiment of the present invention, a plurality of rolling members may be provided as necessary.

  FIG. 4 is a diagram illustrating an installation example of the rolling member 500 when the area scan camera is used.

  As shown in FIG. 4, when the imaging unit 300 is a camera that captures an image by the area scan method, four rolling members 500 are arranged at four corners of the rectangular imaging region W to cover the bottom surface of the inspection object S. Support with rolling contact. As described above, since photographing is performed in a state where the flatness of the photographing region W is maintained, a reliable inspection can be performed.

  In the present embodiment, the stage is shown to be photographed while moving, but as another example, the stage on which the inspection object is placed is fixed, and the photographing unit, the illumination unit, and the rolling member are It is also possible to take an image of the inspection object fixed while moving the scan. For example, an imaging unit, a lighting unit, and a rolling member may be additionally provided depending on the inspection conditions of the inspection object and the user's requirements.

(Second Embodiment)
FIG. 5 is a front view for explaining the configuration of the optical inspection apparatus according to the second embodiment of the present invention, and FIG. 6 is for explaining the configuration of the optical inspection apparatus according to the second embodiment of the present invention. FIG.

  Unlike the first embodiment in which the inspection unit is inspected while moving the stage while the imaging unit, the illumination unit, and the rolling member are fixed, in the second embodiment, the imaging unit and the illumination unit are fixed. In this state, the inspection object is inspected while the rolling member and the stage move together.

  5 and 6, the optical inspection apparatus 10a of the present invention includes a stage 100a, a linear movement unit 200a, an imaging unit 300a, an illumination unit 400a, a rolling member 500a, and the like.

  The stage 100 a includes a body 110 having a bottom surface 112, a first side surface 114, and a second side surface 116. A supporter 120 and a position determining member 130 are provided on the upper stage of the body 110, that is, on the upper stage of the first and second side surfaces 114 and 116. The inspection object S is placed with both side edges supported by the supporter 120. The position determining member 130 is a cylinder for aligning both sides of the inspection object S placed on the supporter 120, and pressurizes both side surfaces of the inspection object S to correct (align) the left and right positions. A space is provided between the first and second side surfaces 114 and 116 of the body 110, and the space is opened in the upper part and the front-rear direction.

  On the other hand, the rolling member 500a is provided on the stage 100a. The rolling member 500a is arranged directly below the line on which the inspection object S is positioned so that the bottom surface of the inspection object S placed on the stage 100a can be supported. 116 is provided on a bracket 190 formed extending from 116.

  The rolling member 500a is for minimizing a distortion phenomenon caused by bending or bending (sagging) of the imaging area of the inspection object S placed on the stage 100a, and directly with the edge of the imaging area W of the inspection object S. A ball caster having a ball 510 in contact therewith. The rolling member 500a is provided on the stage 100a so as to be positioned under the inspection object S, and moves together with the stage 100a. Accordingly, the ball 510 of the rolling member 500a maintains a point contact with the inspection object S at a predetermined interval, and friction due to relative movement between the ball 510 and the inspection object S as in the first embodiment. Can be prevented. The rolling member 500a is provided on the bracket 190 so as to be positioned at a height at which the inspection object S can be in rolling contact with the bottom surface of the inspection object S when the inspection object S is placed on the stage 100a. Although not shown, the bracket 190 is preferably provided on the first and second side surfaces 114 and 116 of the stage 100a so that the height can be adjusted in order to adjust the height of the rolling member 500a.

  As shown in FIG. 7, a large number of balls 510 of the rolling member 500a are provided at predetermined intervals and support the inspection object S as a whole. For example, assuming that the area in which the four balls 510 arranged in four directions can maintain flatness is 100 mm, when the area where the image is taken (the length of the inspection object) is, for example, 500 mm, the six balls 510 are spaced at intervals of 100 mm. Are arranged in two rows, so a total of 12 balls are required.

  Referring to FIG. 7, the bottom surface of the inspection object S corresponding to both ends of the area W where the six balls 510 are imaged in two rows on both sides is supported by rolling contact, and the imaging unit 300 a is in the direction of the arrow (front-rear direction). The moving inspection object S is continuously photographed. In this case, photographing by the photographing unit 300a is performed in a state where the flatness is maintained by the twelve balls 510.

  The rolling member 500a and the stage 100a are moved in the front-rear direction on the base plate 20 by the linear movement unit 200a. The linear movement unit 200 a includes an LM guide 210 and a linear motor 220. The stage 100 a is guided by the LM guide 210 provided on the base plate 20, and moves in the front-rear direction by driving the linear motor 220. In the present embodiment, the case where the linear movement unit 200a includes the LM guide 210 and the linear motor 220 has been illustrated and described. Various mechanisms can be applied.

  The imaging unit 300a is a CCD camera having an image sensor such as a CCD line sensor and a lens (not shown), and images the surface (pattern, etc.) of the inspection object S to acquire video data for the inspection object S. . The acquired video data is provided to a video processing unit (not shown). Although not shown, the optical inspection apparatus 10 includes a video processing unit to which an image photographed from the photographing unit 300a is provided. The video processing unit is configured by a typical computer system (commonly known as a microcomputer), and controls and processes various operations associated with automatic optical inspection. For example, a line scan camera can be used as the imaging unit 300a, and a line scan camera or an area camera can be additionally provided depending on the inspection conditions of the inspection object S and user requirements. The photographing unit 300a is provided on the vertical frame 30 so as to be movable in the left-right direction. The guide rail 32 provided on the vertical frame 30 is provided with a moving plate 34, and the moving plate 34 is provided with a line scan camera which is a photographing unit 300a. That is, the position of the photographing unit 300a can be adjusted to the left and right according to the region to be photographed.

  The illumination unit 400a includes a transmissive illumination 410 that irradiates the inspection object S with transmitted light, and a reflected illumination 420 that irradiates the inspection object S with reflected light. The reflected illumination 420 is disposed above the inspection object S, and the transmitted illumination 410 is disposed below the imaging region of the inspection object S. The transmitted illumination 410 and the reflected illumination 420 output light for acquiring video data for the imaging region of the inspection object S. As light sources of the transmitted illumination 410 and the reflected illumination 420, a large number of light emitting diodes arranged in a linear arrangement, a linear tube fluorescent lamp, a halogen, a metal halide, and the like can be used. A diffusion plate or the like for improving the uniformity of light may be provided on the light source. The reflected illumination 420 is provided on the moving plate 34, and the transmitted illumination 410 is fixedly installed on the horizontal support base 600a. The transmitted illumination 410 and the reflected illumination 420 can be adjusted in height.

  The horizontal support 600a is a structure that is fixed so that the transmitted illumination 410 is positioned in an open space of the stage 100a that moves in the front-rear direction. The horizontal support base 600a is disposed horizontally on the stage 100a in the front-rear direction and across the open space of the stage 100a, and is provided on a fixed base 610 provided on the base plate 20 at both ends. The horizontal support base 600a is provided with a transmission illumination 410.

  The configuration and operation of the optical inspection apparatus according to the present invention have been described with reference to the above description and drawings. However, this is merely an example. Various changes and modifications can be made without departing from the technical idea of the present invention.

It is a front view for demonstrating the structure of the optical inspection apparatus by 1st Embodiment of this invention. It is a side view for demonstrating the structure of the optical inspection apparatus by 1st Embodiment of this invention. 2 is a view showing a state in which a pair of rolling members according to the first embodiment of the present invention supports both ends of an imaging region W. FIG. It is a figure which shows the example of installation of the rolling member in the case of using the area scan camera by 1st Embodiment of this invention. It is a front view for demonstrating the structure of the optical inspection apparatus by 2nd Embodiment of this invention. It is a side view for demonstrating the structure of the optical inspection apparatus by 2nd Embodiment of this invention. It is a figure which shows the state which 12 balls by 2nd Embodiment of this invention are supporting the both ends of the imaging | photography area | region W. FIG.

Explanation of symbols

100 stage 200 linear movement unit 300 photographing unit
400 Lighting unit 500 Rolling member

Claims (14)

A stage on which the inspection object is placed;
An imaging unit for imaging the inspection object placed on the stage;
An illumination unit for irradiating the inspection object with light;
An optical inspection apparatus comprising: a rolling member that supports an edge of an area imaged by the imaging unit in order to maintain flatness of the imaging area.   The optical inspection apparatus according to claim 1, wherein the rolling member is a ball caster having a ball in rolling contact with the inspection object.   The optical inspection apparatus according to claim 1, further comprising a linear movement unit that moves the stage in the front-rear direction so that the imaging unit continuously images the inspection object. The photographing unit includes a line scan camera for photographing by a line scan method,
The optical inspection apparatus according to claim 1, wherein the rolling member supports both ends of the imaging region imaged by the line scan camera. The photographing unit includes an area camera for photographing by an area scan method,
The optical inspection apparatus according to claim 1, wherein the rolling member supports a corner of the imaging region captured by the area camera.   The optical system according to claim 1, wherein the illumination unit includes at least one of transmission illumination that irradiates the inspection object with transmitted light and reflected illumination that irradiates the inspection object with reflected light. Inspection device.   The stage has a space that supports left and right edges of the inspection object and is open in a front-rear movement direction so that the rolling member is positioned below the inspection object. The optical inspection apparatus described in 1. The stage includes a body having a space opened in a front-rear movement direction so that the rolling member is positioned below the inspection object;
The optical inspection apparatus according to claim 1, further comprising a supporter provided on an upper stage of the body and supporting left and right edges of the inspection object.   The optical inspection apparatus according to claim 8, wherein the stage further includes a position determination member that aligns the positions of the inspection objects placed on the supporter.   2. The optical inspection apparatus according to claim 1, further comprising a horizontal support provided horizontally in the front-rear movement direction of the stage, passing through an open space of the stage, and provided with the rolling member. The optical inspection apparatus described. A stage on which the inspection object is placed;
An imaging unit for imaging the inspection object placed on the stage;
An illumination unit for irradiating the inspection object with light,
The stage includes a rolling member that is in rolling contact with the inspection object in order to maintain the flatness of the inspection object.   The optical inspection apparatus according to claim 11, wherein the rolling member includes a plurality of balls that support an imaging region edge of an inspection object imaged by the imaging unit at predetermined intervals.   The optical inspection apparatus further includes a linear movement unit that moves the stage together with the rolling member to an imaging region of the imaging unit so that the imaging unit continuously images the inspection object. The optical inspection apparatus described in 1.   The optical inspection apparatus according to claim 12, wherein the illumination unit includes transmitted illumination that irradiates the inspection object with transmitted light and reflected illumination that irradiates the inspection object with reflected light.

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