JP2013113828A - Lighting device for inspection and inspection system having the same - Google Patents

Lighting device for inspection and inspection system having the same Download PDF

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Publication number
JP2013113828A
JP2013113828A JP2011263247A JP2011263247A JP2013113828A JP 2013113828 A JP2013113828 A JP 2013113828A JP 2011263247 A JP2011263247 A JP 2011263247A JP 2011263247 A JP2011263247 A JP 2011263247A JP 2013113828 A JP2013113828 A JP 2013113828A
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Japan
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inspection
light
laser light
image
illumination
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JP2011263247A
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Japanese (ja)
Inventor
Koichi Wakitani
康一 脇谷
Hiroyasu Kubo
泰康 久保
Akihiro Sunouchi
聡裕 巣之内
Hitoshi Tanaka
仁 田中
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Panasonic Corp
パナソニック株式会社
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Priority to JP2011263247A priority Critical patent/JP2013113828A/en
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Abstract

PROBLEM TO BE SOLVED: To provide a lighting device which allows each of a plurality of inspection object regions of an inspection object to be properly illuminated, achieving reduced inspection time with high inspection accuracy.SOLUTION: A lighting device comprises: a plurality of light source devices LG, LB, and LR which emit color light beams different from each other; a spacial light modulation element 25 which modulates the light beams from the respective light source devices; a projection optical system 28 which projects tha light beam from the spacial light modulation element on a test surface Sa of a base plate S; and an image display control part 74 which controls the spacial light modulation element in accordance with a predetermined image signal so as to form a projection pattern of the light beam from the projection optical system. The image signal for forming the projection pattern is created based on the position data of the inspection object region on the test surface. This allows a spacial light modulation element control part to form a projection pattern including an image region in accordance with the inspection object region.

Description

  The present invention relates to an illumination device for inspection and an inspection system including the same, and more particularly to an illumination device and an inspection system suitable for inspecting an inspection object such as a substrate having a plurality of inspection object parts.

  2. Description of the Related Art Conventionally, with respect to inspection of printed circuit boards on which electronic components are mounted, a method has been widely used in which the appearance of a substrate is photographed with a camera and the electronic component is fixed from the obtained image. In this type of inspection, since the illumination with respect to the inspection target part affects the quality of the inspection accuracy (accuracy of image processing and visual inspection), various contrivances have been made regarding the color of illumination, the irradiation angle, and the like.

  For example, in an illumination device for inspection having a plurality of LED lamps of multicolor light emission type, each LED lamp is arranged in a range surrounding the optical axis of the camera and having a predetermined angular width with respect to the imaging target area on the substrate And there exists what implement | achieves the illumination pattern according to the content of the test | inspection by controlling the lighting state of each LED lamp and changing the color and irradiation angle of illumination light (refer patent document 1).

  According to this prior art, the LED lamps are classified for each region having a different irradiation angle range with respect to the imaging target region, and the lighting state of each LED lamp is controlled in units of these regions. There is an advantage that when the inclination state of the solder is inspected by using the same illumination device, it is possible to perform illumination suitable for the inspection using the same illumination device.

JP 2006-47290 A

  However, when inspecting an inspection object such as a substrate having a plurality of inspection object parts having different surface characteristics or the like by the conventional technique as described in Patent Document 1, the inspection object parts are inspected simultaneously. (That is, it is necessary to switch to an appropriate illumination for each region to be inspected and to perform imaging each time), so it is necessary to repeatedly perform inspections with the same illumination device or to prepare a plurality of illumination devices.

  In addition, when inspecting an inspection object such as a substrate having a plurality of inspection object parts having different shapes (two-dimensional shapes), it is desirable to use an illumination pattern according to the shape of each inspection object part. In the prior art, it has been difficult to realize such an illumination pattern.

  The present invention has been devised in view of such problems of the prior art, and even when an inspection object having a plurality of inspection object parts is inspected, each inspection object part is appropriately illuminated. Then, it aims at providing the illuminating device for a test | inspection which can shorten test | inspection time, maintaining a test | inspection precision favorable, and a test | inspection system provided with the same.

  An inspection illumination device according to the present invention includes a plurality of light source devices that emit light of different colors, a spatial light modulation element that modulates light from each of the light source devices, and an inspection of light from the spatial light modulation element. A projection optical system for projecting onto a surface to be inspected of an object, and a spatial light modulation element control unit that forms a projection pattern of light from the projection optical system by controlling the spatial light modulation element according to a predetermined video signal The video signal is generated based on position information of the inspection target part on the inspection surface, and the spatial light modulation element control unit forms a projection pattern including an image region corresponding to the inspection target part. It is characterized by that.

  As described above, according to the present invention, even when an inspection object having a plurality of inspection target parts is inspected, an inspection projection pattern is formed by the video signal generated based on the position information of the inspection target part. Each of the inspection target parts can be appropriately illuminated. As a result, there is an excellent effect that the inspection time can be shortened while maintaining the inspection accuracy satisfactorily.

The block diagram of the test | inspection system 1 provided with the illuminating device 3 for a test | inspection which concerns on 1st Embodiment. FIG. 1 is a main part configuration diagram of an optical engine unit 15 incorporated in the illumination device 3 in FIG. 1 is a perspective view of a main part of an optical engine unit 15 incorporated in the illumination device 3 in FIG. The schematic diagram which shows the condition of the green laser beam in the green laser light source device LG in FIG. Functional block diagram of the inspection system 1 according to the first embodiment The figure which shows an example of the illumination pattern with respect to the to-be-inspected surface Sa of the board | substrate S by the illuminating device 3 which concerns on 1st Embodiment. The figure which shows the example when position shift generate | occur | produces in the illumination pattern shown in FIG. Explanatory drawing about the trapezoid correction function of the inspection system 1 shown in FIG. Operation flow diagram of illumination method during inspection of inspection system 1 shown in FIG. The block diagram which shows the principal part of the test | inspection system 1 which concerns on 2nd Embodiment. The block diagram which shows the principal part of the test | inspection system 1 which concerns on 3rd Embodiment.

  A first invention made to solve the above-described problems is a plurality of light source devices that emit light of different colors in a lighting apparatus for inspection, and a spatial light modulation element that modulates light from each of the light source devices. And a projection optical system for projecting light from the spatial light modulation element onto the surface to be inspected of the inspection object, and the light from the projection optical system by controlling the spatial light modulation element according to a predetermined video signal. A spatial light modulation element control unit that forms a projection pattern of the image, wherein the video signal is generated based on positional information of an inspection target part on the surface to be inspected, and the spatial light modulation element control part includes the inspection target part The projection pattern including the image area corresponding to is formed.

  According to this, even when inspecting an inspection object having a plurality of inspection object parts, each inspection object part is formed by forming a projection pattern for inspection with a video signal generated based on the position information of the inspection object part. Can be appropriately illuminated. As a result, it is possible to shorten the inspection time while maintaining good inspection accuracy.

  Further, the second invention relates to the first invention, wherein the image region corresponding to the examination target region has a color different from that of an image region corresponding to another region other than the examination target region. .

  According to this, it is possible to increase the inspection accuracy of the inspection target part by forming a projection pattern with a color determined so as to improve the identification and visibility of the inspection target part.

  The third invention relates to the first or second invention, wherein the inspection object is a substrate, and the inspection object part is an electronic component mounted on the substrate.

  According to this, the electronic component mounted on the board is highlighted by illumination, and its distinguishability and visibility are improved, and it becomes possible to easily detect the defect or missing.

  A fourth invention relates to any one of the first to third inventions, wherein the light source device includes a light source device that emits at least one of infrared light and ultraviolet light.

  According to this, the freedom degree of the structure for identifying or visually recognizing the test | inspection site | part in a test target object increases by forming a projection pattern using infrared light or ultraviolet light in addition to visible light.

  Further, the fifth invention relates to any one of the first to fourth inventions, further comprising a plurality of illuminance sensors for detecting reflected light illuminance of light of different parts on the surface to be inspected, and a detection result of the illuminance sensor And a trapezoidal distortion correction unit for correcting the trapezoidal distortion of the projection pattern.

  According to this, even when light is projected obliquely rather than in a direction orthogonal to the surface to be inspected of the inspection object, it is possible to more appropriately illuminate the inspection target part while suppressing unevenness in illuminance.

  Further, a sixth invention relates to any one of the first to fifth inventions, wherein the light from the projection optical system is a strip-like light that crosses the surface to be inspected, and the video signal is the inspected It is set as the structure changed according to the projection position of the said strip | belt-shaped light in a surface.

  According to this, even when the projectable area of light from the projection optical system is smaller than the surface to be inspected, each inspection is performed by projecting light from the projection optical system so as to scan the surface to be inspected. Appropriate illumination can be performed on the target region.

  According to a seventh aspect of the present invention, there is provided an inspection system including the inspection illumination device according to any one of the first to sixth aspects, the imaging device configured to image the surface to be inspected, and the imaging device. By performing image processing of the captured image, an image processing unit that acquires a position of the inspection target region and a position of the image region corresponding to the inspection target region, and the inspection target region acquired by the image processing unit And an illumination control unit that generates the video signal so that the position of the image area matches the position of the image area.

  According to this, since the projection pattern is formed so as to eliminate the deviation between the position of the image area projected toward the inspection target part and the position of the imaged inspection target part, it is more suitable for the inspection target part. Appropriate lighting can be implemented.

  According to an eighth aspect of the present invention, there is provided an inspection system including the inspection illumination device according to any one of the first to sixth aspects, the imaging device configured to image the surface to be inspected, and the imaging device. The display device displays a captured image to the operator, and further includes an input device for the operator to input information for changing the projection pattern.

  According to this, since the operator can easily change the projection pattern while confirming the captured image displayed on the display device, the operator can perform more appropriate illumination on the examination target part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a configuration diagram illustrating an outline of an inspection system 1 including an inspection illumination device 3 according to the first embodiment. The inspection system 1 is for inspecting defects, omissions, fixed states, etc. of electronic components (including conductor patterns and soldering parts) mounted on a substrate (electronic circuit board) S which is an inspection object. A camera (imaging device) 2 that images the appearance of the substrate S, an illumination device 3 that illuminates the surface to be inspected (here, the component surface) Sa of the substrate S when the camera 2 captures images, It mainly includes a PC (Personal Computer) 4 that sets various operations to be executed by the lighting device 3 and performs image processing of an image captured by the camera 2.

  On the surface Sa to be inspected of the substrate S, there are a plurality of inspection object parts to be inspected by the inspection system 1. Here, an example in which surface-mounted LSI packages (electronic components) 5 and 6, a predetermined conductor pattern 7 formed of a conductive material, and a management information display unit 8 are inspected parts is shown. In addition, the configuration of the electronic components and the like mounted thereon is not limited to that shown here, and various modifications can be made. The substrate S is transported on the transport belt B, and the inspection surface Sa is imaged by the camera 2 at the inspection position shown in FIG.

  The camera 2 has a known configuration including an image sensor made up of a CCD (Charge Coupled Device) or the like, and sends moving image data or still image data generated by imaging to the PC 4. The camera 2 is arranged above the substrate S so that the optical axis thereof is substantially perpendicular to the surface Sa to be inspected. However, the camera 2 has a slight angle to detect a three-dimensional object on the surface Sa to be inspected. You may arrange it.

  The illuminating device 3 projects the illumination light 10 onto the substrate S at the inspection position from above. As a result, the illumination screen P is formed so as to overlap the surface to be inspected Sa. The optical axis of the illumination light 10 is arranged to be inclined with respect to a direction perpendicular to the surface to be inspected Sa. However, the present invention is not limited thereto, and is substantially perpendicular to the surface to be inspected similarly to the optical axis of the camera 2. You may arrange.

  The PC 4 is communicably connected to the camera 2 and the illumination device 3 via cables, respectively, and an LCD (display device) 11 that displays an image captured by the camera 2 and various operations of the camera 2 and the illumination device 3. And an input device 12 for an operator to input settings. The inspection system 1 is not limited to the PC 4, and any information processing apparatus having the same function can be used.

  FIG. 2 is a main part configuration diagram of the optical engine unit 15 built in the lighting device 3 in FIG. 1, and FIG. 3 is a main part perspective view of the optical engine unit 15. The optical engine unit 15 projects a required image for illumination at the time of substrate inspection, a green laser light source device LG that outputs green laser light, a red laser light source device LR that outputs red laser light, A blue laser light source device LB that outputs blue laser light, and a liquid crystal reflective spatial light modulator that spatially modulates the laser light from each of the laser light source devices LG, LR, and LB in accordance with a video signal to form an image 25, a polarization beam splitter 26 that reflects the laser light from each of the laser light source devices LG, LR, and LB to irradiate the spatial light modulation element 25 and transmits the modulated laser light emitted from the spatial light modulation element 25; A relay optical system 27 for guiding the laser light emitted from each of the laser light source devices LG, LR, and LB to the polarization beam splitter 26; and the polarization beam splitter 2 And a projection optical system 28 including a projection lens that projects the modulated laser light transmitted to the outside (inspection surface Sa of the substrate S) with.

  The illumination device 3 displays a color image by a so-called field sequential method (time-division display method), and laser light of each color is sequentially output from each laser light source device LG, LR, LB in a time-division manner. The image by light is recognized as a color image by the afterimage.

  The relay optical system 27 requires the collimator lenses 31 to 33 that convert the laser beams of the respective colors emitted from the laser light source devices LG, LR, and LB into parallel beams, and the laser beams of the respective colors that have passed through the collimator lenses 31 to 33. First and second dichroic mirrors 34 and 35 guided in the direction of, a diffusion plate 36 for diffusing the laser light guided by the dichroic mirrors 34 and 35, and converting the laser light that has passed through the diffusion plate 36 into a convergent laser And a field lens 37.

  When the side from which the laser light is emitted from the projection port 28a of the projection optical system 28 toward the outside is the front side, the blue laser light is emitted backward from the blue laser light source device LB. The green laser light source device LG and the red laser light source device LR emit green laser light and red laser light so that the optical axis of the green laser light and the optical axis of the red laser light are orthogonal to the optical axis of the blue laser light. The emitted blue laser light, red laser light, and green laser light are guided to the same optical path by the two dichroic mirrors 34 and 35. That is, the blue laser light and the green laser light are guided to the same optical path by the first dichroic mirror 34, and the blue laser light, the green laser light, and the red laser light are guided to the same optical path by the second dichroic mirror 35.

  The first and second dichroic mirrors 34 and 35 are formed by forming a film for transmitting and reflecting laser light of a predetermined wavelength on the surface, and the first dichroic mirror 34 transmits blue laser light. And reflects the green laser light. The second dichroic mirror 35 transmits red laser light and reflects blue laser light and green laser light.

  Each of these optical members is supported by a casing 41 formed of a material having high thermal conductivity such as copper or aluminum. The casing 41 functions as a radiator that dissipates heat generated in the laser light source devices LG, LR, and LB, and is formed of a material having high thermal conductivity such as aluminum or copper. Further, the spatial light modulation element 25, the polarization beam splitter 26, the relay optical system 27, the projection optical system 28, and the like are attached to the casing 41. The upper opening of the housing 41 is sealed with a metal lid 39 in order to prevent laser light from leaking outside from the projection optical system 28.

  The green laser light source device LG is attached to a mounting plate 42 formed on the housing 41 in a state of projecting sideways from the main body portion 21a of the housing 41. The mounting plate 42 has a side wall portion 44 extending from the corner portion where the front wall portion 43 and the side wall portion 44 that are respectively positioned in front and side of the accommodation space of the relay optical system 27 are orthogonal to each other. It protrudes in a direction perpendicular to. The red laser light source device LR is attached to the outer surface of the side wall 44 while being held by the holder 45. The blue laser light source device LB is attached to the outer surface of the front wall 43 while being held by the holder 46. In addition, about the green laser light source device LG, the structure attached to the outer surface of the side wall part 44 similarly to the red laser light source device LR is also possible.

  The red laser light source device LR and the blue laser light source device LB are configured by a so-called CAN package, and the optical axis is positioned on the central axis of the can-shaped exterior portion with the laser chip that outputs the laser light supported by the stem. The laser beam is emitted from a glass window provided in the opening of the exterior part. The red laser light source device LR and the blue laser light source device LB are fixed to the holders 45 and 26 by, for example, press-fitting into the mounting holes 47 and 48 opened in the holders 45 and 26. The heat generated by the laser chips of the blue laser light source device LB and the red laser light source device LR is transmitted to the housing 41 via the holders 45 and 26 to be dissipated. Each holder 45, 26 is formed of a material having high thermal conductivity such as aluminum or copper.

  The red laser beam has a wavelength of 640 nm, but may be any wavelength as long as it can be recognized as at least red. For example, a laser beam having a wavelength range in which the peak wavelength is in the range of 610 to 750 nm may be used. Further, the blue laser light has a wavelength of 450 nm, but may be any wavelength that can be recognized as at least blue. For example, a laser beam having a wavelength region in which the peak wavelength is in the range of 435 to 480 nm may be used.

  As shown in FIG. 2, the green laser light source device LG includes a semiconductor laser 51 that outputs excitation laser light, and a FAC (Fast−) that is a condenser lens that condenses the excitation laser light output from the semiconductor laser 51. An Axis Collimator) lens 52 and a rod lens 53, a solid-state laser element 54 that is excited by an excitation laser beam and outputs a basic laser beam (infrared laser beam), and a half-wavelength laser beam by converting the wavelength of the basic laser beam. A wavelength conversion element 55 that outputs (green laser light), a concave mirror 56 that constitutes a resonator together with the solid-state laser element 54, a glass cover 57 that prevents leakage of excitation laser light and fundamental wavelength laser light, A supporting base 58 and a cover body 59 that covers each part are provided.

  FIG. 4 is a schematic diagram showing a state of green laser light in the green laser light source device LG in FIG. The laser chip 61 of the semiconductor laser 51 outputs excitation laser light having a wavelength of 808 nm. The FAC lens 52 reduces the spread of the first axis of the laser beam (the direction perpendicular to the optical axis direction and along the drawing sheet). The rod lens 53 reduces the spread of the slow axis of laser light (in the direction perpendicular to the drawing sheet).

The solid-state laser element 54 is a so-called solid-state laser crystal, and is excited by excitation laser light having a wavelength of 808 nm that has passed through the rod lens 53 to output fundamental wavelength laser light (infrared laser light) having a wavelength of 1064 nm. This solid-state laser element 54 is obtained by doping an inorganic optically active substance (crystal) made of Y (yttrium) VO 4 (vanadate) with Nd (neodymium), and more specifically, YVO 4 as a base material. The Y is doped by substitution with Nd +3 which is an element that emits fluorescence.

  On the side of the solid-state laser element 54 facing the rod lens 53, a film having a function of preventing reflection of excitation laser light having a wavelength of 808 nm and high reflection of fundamental wavelength laser light having a wavelength of 1064 nm and half-wavelength laser light having a wavelength of 532 nm. 62 is formed. On the side of the solid-state laser element 54 facing the wavelength conversion element 55, a film 63 having an antireflection function for a fundamental wavelength laser beam having a wavelength of 1064 nm and a half wavelength laser beam having a wavelength of 532 nm is formed.

  The wavelength conversion element 55 is a so-called SHG (Second Harmonics Generation) element, which converts the wavelength of a fundamental wavelength laser beam (infrared laser beam) with a wavelength of 1064 nm output from the solid-state laser element 54 to a half-wavelength laser with a wavelength of 532 nm. Light (green laser light) is generated. This wavelength conversion element 55 is provided with a periodic polarization reversal structure in which a region where polarization is reversed and a region as it is are alternately formed in a ferroelectric crystal. A fundamental wavelength laser beam is incident in the arrangement direction. As the ferroelectric crystal, for example, a material obtained by adding MgO to LN (lithium niobate) is used.

  On the side of the wavelength conversion element 55 facing the solid-state laser element 54, a film 64 having functions of preventing reflection of the fundamental wavelength laser light having a wavelength of 1064 nm and highly reflecting the half wavelength laser light having a wavelength of 532 nm is formed. On the side of the wavelength conversion element 55 facing the concave mirror 56, a film 65 having an antireflection function for the fundamental wavelength laser beam having a wavelength of 1064 nm and the half wavelength laser beam having a wavelength of 532 nm is formed.

  The concave mirror 56 has a concave surface on the side facing the wavelength conversion element 55, and this concave surface has a function of high reflection with respect to a fundamental wavelength laser beam with a wavelength of 1064 nm and antireflection with respect to a half wavelength laser beam with a wavelength of 532 nm. A film 66 is formed. As a result, the fundamental wavelength laser beam having a wavelength of 1064 nm resonates and is amplified between the film 62 of the solid-state laser element 54 and the film 66 of the concave mirror 56.

  In the wavelength conversion element 55, a part of the fundamental wavelength laser light having a wavelength of 1064 nm incident from the solid-state laser element 54 is converted into a half-wavelength laser light having a wavelength of 532 nm, and the fundamental wavelength of 1064 nm that has passed through the wavelength conversion element 55 without being converted is converted. The wavelength laser beam is reflected by the concave mirror 56 and is incident on the wavelength conversion element 55 again, and is converted into a half-wavelength laser beam having a wavelength of 532 nm. The half-wavelength laser light having a wavelength of 532 nm is reflected by the film 64 of the wavelength conversion element 55 and emitted from the wavelength conversion element 55.

  Here, the laser beam B1 incident on the wavelength conversion element 55 from the solid-state laser element 54, converted in wavelength by the wavelength conversion element 55, and emitted from the wavelength conversion element 55, and once reflected by the concave mirror 56 and converted in wavelength. In the state where the laser beam B2 incident on the element 55, reflected by the film 64 and emitted from the wavelength conversion element 55 overlaps with each other, the half-wavelength laser light having a wavelength of 532 nm and the fundamental wavelength laser light having a wavelength of 1064 nm interfere with each other. Cause output to drop.

  Therefore, here, the wavelength conversion element 55 is inclined with respect to the optical axis direction so that the laser light beams B1 and B2 do not overlap each other by the refraction action on the entrance surface and the exit surface. Interference between the wavelength laser beam and the fundamental wavelength laser beam having a wavelength of 1064 nm is prevented, so that a decrease in output can be avoided.

  The glass cover 57 shown in FIG. 2 is formed with a film that does not transmit these laser beams in order to prevent the excitation laser beam having a wavelength of 808 nm and the fundamental wavelength laser beam having a wavelength of 1064 nm from leaking to the outside. ing.

  In the above example, the laser chip 61, the solid state laser element 54, and the wavelength conversion element 55 of the green laser light source device LG are respectively pumping laser light having a wavelength of 808 nm, fundamental wavelength laser light (infrared laser light) having a wavelength of 1064 nm, Although a half-wavelength laser beam (green laser beam) having a wavelength of 532 nm is output, the present invention is not limited to this. The laser light finally outputted from the green laser light source device LG may be anything that can be recognized as green, and for example, laser light in a wavelength region in which the peak wavelength is in the range of 500 nm to 560 nm may be outputted. Further, the green laser light source device LG does not convert the wavelength of the infrared laser light as described above, and, like the red laser light source device LR and the blue laser light source device LB, a semiconductor laser that outputs green laser light. A chip may be used.

  FIG. 5 is a functional block diagram of the inspection system 1 shown in FIG. 1, and FIG. 6 is a diagram showing an example of an illumination pattern for the surface Sa to be inspected of the substrate S.

  The illumination device 3 includes an optical engine unit 15 in which optical components are accommodated, and a control unit 16 in which a substrate for controlling the optical components in the optical engine unit 15 is accommodated.

  The control unit 16 includes a laser light source control unit 71 that controls the laser light source devices LG, LR, and LB of each color, and an image display control unit (spatial space) that controls the spatial light modulation element 25 based on a video signal input from the PC 4. A light modulation element control unit) 74, a power source unit 75 that supplies power supplied from the PC 4 to the laser light source control unit 71 and the image display control unit 74, and a main control unit (trapezoidal distortion correction unit) that collectively controls each unit. 76).

  Based on the image display signal input from the image display controller 74, the main controller 76 controls each laser light source device LG, LR, LB as a control signal for controlling the lighting of the laser light source devices LG, LR, LB of each color. A lighting permission signal for permitting lighting and a lighting signal for lighting each of the red, green, and blue laser light source devices LG, LR, and LB are generated, and these control signals are output to the laser light source controller 71. Although details will be described later, the main control unit 76 has a function of correcting trapezoidal distortion of illumination light (projected image).

  The laser light source control unit 71 is a drive control signal (Ig, Ir, and Ib) for controlling application of a drive current to each laser light source device LG, LR, LB based on the control signal input from the main control unit 76. Is output to each laser light source device LG, LR, LB.

  The image display control unit 74 generates a reference voltage signal and a pixel voltage signal as control signals for controlling the operation of the spatial light modulation element 25 based on the video signal input from the PC 4, and uses these control signals as the spatial light. Output to the modulation element 25. Regarding the pixel voltage signal, there are as many signals as the number of pixels of the spatial light modulator 25.

  The spatial light modulation element 25 is a reflection type liquid crystal display element, so-called LCOS (Liquid Crystal On Silicon), and the laser beam transmitted through the liquid crystal layer formed on the silicon substrate is reflected by the reflection layer on the silicon substrate and emitted. It is the thing of the structure to make it. In this spatial light modulator 25, the output (luminance) of the laser light increases or decreases in accordance with the pixel voltage signal input from the image display control unit 74, and is input in a time-sharing manner from the laser light source devices LG, LR, and LB of each color. The required hue can be displayed by increasing or decreasing the output of the laser light of each color. Further, the polarity (p and n) of the spatial light modulation element 25 is controlled based on the reference voltage signal input from the image display control unit 74, and the positive / negative of the pixel voltage signal is inverted according to the reference voltage signal. .

  The PC 4 inspects the substrate S with respect to the illumination control unit 81 that generates a video signal for illumination based on the position information of each inspection target part included in the substrate S and the illumination information for each inspection target part, and the captured image of the camera 2. And an image processing unit 82 that performs necessary image processing. Here, the position information of the inspection target part includes information such as the position and shape (contour) of the inspection target part. In addition, the illumination information for the inspection target part includes information such as the color (hue, brightness, saturation), illuminance, and shape of the image projected on the inspection target part. Note that the function of each unit in the PC 4 is realized by information processing based on a predetermined control program.

  The illumination control unit 81 acquires the position information of the examination target part based on the image processing result by the image processing unit 82 and the operation input from the input device 12 (see FIG. 1) by the operator. In this case, the image processing unit 82 can perform image recognition of the surface Sa to be inspected using a well-known image recognition technique, thereby extracting the contours of the respective inspection target portions and estimating their positions. Further, the operator can input the position information of the inspection target part and the illumination information for the inspection target part into the PC 4 in advance based on the product specification of the substrate S. Thereby, in the illuminating device 3, the image display control part 74 can form arbitrary illumination patterns (namely, the projection pattern of the light from the projection optical system 28) with the screen based on the light from the spatial light modulation element 25. Thus, it is possible to simultaneously perform appropriate illumination (that is, illumination for improving identification and visibility of each inspection target part) on the inspection target parts having different surface characteristics and the like on the substrate S.

  Here, with regard to the illumination pattern, one or more image areas (light projection areas) each having an arbitrary color, illuminance, and shape (outline) are set for each inspection target part. In the present embodiment, as shown in FIG. 6, a plurality of line-shaped image areas 85 and 86 are set across a three-dimensional LSI package 5 and 6 having a predetermined height from the surface Sa to be inspected. Is done. In addition, a rectangular image area 87 having a predetermined color is set for the conductor pattern 7 occupying a rectangular area on the inspection surface Sa. Similarly, a rectangular image area 88 having a predetermined color is set for the management information display unit 8 occupying a rectangular area on the surface Sa to be inspected. As a result, the operator can confirm the lack of the LSI packages 5 and 6 by distorting the projected line image, and the conductor pattern 7 and the information display unit 8 are highlighted by the projection of the rectangular image. As a result, the presence or absence of these defects can be confirmed.

  As for the color of the image projected on the examination target part, for example, the same color as that of the main part of the examination target part or a complementary color can be selected. In some cases, monochrome is also possible. Depending on the configuration of the region to be inspected, a plurality of colors (for example, gradation) can be set in one image region. Further, the contour shape of the image projected on the inspection target part is the same as the area occupied by the inspection target part in the inspection surface Sa (plan view), or a shape slightly enlarged or reduced with respect to the area. can do. In addition, other regions other than the region to be inspected on the surface Sa to be inspected (at least a predetermined region around the region to be inspected) have a color different from the color of the image region corresponding to the region to be inspected, for example, a white image (White light) can be projected. Further, the substrate S may be inspected automatically by the image processing unit 82 using a known image recognition technique without depending on the operator.

  FIG. 7 is a diagram illustrating an example when a positional shift occurs in the illumination pattern illustrated in FIG. 6. In the inspection system 1, the position of each inspection target part and the position of the image area corresponding thereto may not match due to an error in the installation position of the illumination device 3, a transport error of the substrate S, or the like. On the other hand, the image processing unit 82 can estimate the position of each image region by extracting the contour of the image projected on each examination target site by performing image recognition of the captured image. The illumination control unit 81 compares the position information of each examination target portion acquired from the image processing unit 82 with the position of each image region corresponding to the information, and the video is displayed so that both positions (for example, the center of gravity position) match. A signal can be generated (corrected). As a result, the displacement of the illumination pattern is eliminated, and an appropriate illumination pattern as shown in FIG. 6 is obtained.

  FIG. 8 is an explanatory diagram regarding the trapezoid correction function of the inspection system 1 shown in FIG. As described above, when the optical axis of the illumination light 10 of the illuminating device 3 is arranged to be inclined with respect to the surface Sa to be inspected, a screen (entire image) that should be originally projected as a rectangle as shown in FIG. P becomes a shape distorted in a trapezoidal shape.

  Therefore, the inspection system 1 is provided with a plurality of photo detectors (illuminance sensors) 95a to 95d, and by these photo detectors 95a to 95d, each part of the screen P (here, each apex of the reference rectangular area) Pa to The reflected light illuminance at Pd is measured. And the main control part 76 (refer FIG. 5) of the illuminating device 3 performs trapezoid distortion correction (keystone correction) based on the measurement result of reflected light illuminance. More specifically, the main control unit 76 compares the reflected light illuminance at each part with a predetermined reference illuminance (here, the average illuminance at each part), and determines that a portion larger than the reference illuminance is distorted in the reduction direction. Then, the screen P is corrected so as to expand from the screen center toward the outside. On the other hand, for a part smaller than the reference illuminance, the screen P is corrected so as to be distorted in the enlargement direction and to be reduced inward toward the center of the screen.

  By repeatedly performing such reflected light illuminance measurement and trapezoidal distortion correction processing, the screen P can be made into a rectangular screen without distortion, and the reflected light intensity at each part Pa to Pd of the screen P is uniform. Can be As a result, it is possible to more appropriately illuminate the inspection target part while suppressing unevenness in illuminance on the inspection surface Sa. Note that the photodetectors 95a to 95d shown in FIG. 8 can be built in or attached to the illumination device 3, and can also be provided with a necessary optical system (such as a condenser lens).

  FIG. 9 is an operation flowchart showing an outline of an illumination method at the time of inspection of the inspection system 1 shown in FIG. First, the illumination control unit 81 of the PC 4 acquires position information and illumination information of each examination target part input in advance by an operator (ST101). Here, the position information of each inspection target part may be acquired based on the image recognition result of the captured image of the substrate S by the camera 2. Subsequently, the illumination control unit 81 generates a video signal based on the position information and the illumination information (ST102).

  The image display controller 74 of the illumination device 3 generates a control signal for controlling the operation of the spatial light modulator 25 based on the video signal acquired from the illumination controller 81 (ST103). Then, the spatial light modulation element 25 increases or decreases the output of the laser light of each color input in a time-sharing manner from the laser light source devices LG, LR, and LB of each color based on the control signal from the image display control unit 74. An image having a predetermined color, illuminance, and shape is projected onto the target part (ST104).

  Thereafter, the main control unit 76 of the illumination device 3 performs trapezoidal distortion correction based on the measurement result of the reflected light illuminance of each unit on the illumination screen (ST105). Subsequently, the image processing unit 82 of the PC 4 acquires a captured image of the substrate S irradiated with the illumination light from the camera 2, and performs image recognition of the captured image (ST106).

  The illumination control unit 81 determines the presence / absence of a displacement of the illumination pattern based on the image recognition result of the image processing unit 82 (ST107). Therefore, if there is a displacement of the illumination pattern (ST107: Yes), the illumination control unit 81 outputs the video signal so that the position of the region to be inspected matches the position of each image region corresponding thereto. to correct. As a result, an image aligned with each inspection target part is projected.

  Note that steps ST106 and ST107 can also be executed based on the operation of the operator. For example, when the operator confirms the displacement of the illumination pattern from the captured image of the substrate S displayed on the LCD 11, the operator corrects the displacement by operating the input device 12, the mouse, the touch panel, and the like, and based on this operation. The illumination control unit 81 can generate a video signal. At this time, the operator can finely adjust the color, shape, and the like of the image projected on each inspection target part, along with the operation of correcting the displacement of the illumination pattern.

  As described above, in the inspection system 1 according to the present invention, since it is possible to appropriately illuminate each inspection target part, it is possible to shorten the inspection time while maintaining good inspection accuracy. Moreover, since it was set as the structure which lights by the screen based on a video signal, there exists an advantage that the projection pattern for improving the identification property and visibility of a test | inspection site | part can be implement | achieved by simple structure. In particular, an electronic component or the like mounted on the substrate S can be highlighted by illumination, its distinguishability and visibility are improved, and the defect or missing can be easily detected.

Second Embodiment
FIG. 10 is a configuration diagram illustrating a main part of the inspection system 1 according to the second embodiment. In FIG. 10, the same code | symbol is attached | subjected about the component similar to the above-mentioned 1st Embodiment. In the second embodiment, items not particularly mentioned below are the same as those in the first embodiment.

  In the second embodiment, the illumination light from the illumination device 3 is not irradiated on the entire surface to be inspected Sa of the substrate S, but is perpendicular to the transport direction of the substrate S indicated by the arrow A as shown in FIG. This is different from the case of the first embodiment in that the slit light (band-like light) 91 crosses the substrate S in the direction of. The camera 2 is a line sensor camera that operates in synchronization with the transport belt B.

  In the inspection system 1 according to the second embodiment, when the substrate S is transported on the transport belt B, the screen P based on the slit light 91 is scanned from the front end to the end of the substrate S in the transport direction. The camera 2 continuously images each part on which 91 is projected. In this case, the video signal generated by the PC 4 is equivalent to that obtained by cutting out a part of the video signal in the first embodiment described above, and the screen P based on the slit light 91 is projected on the surface Sa to be inspected (scanning). Depending on the position). Further, the image processing unit 82 of the PC 4 can generate an image that displays the entire surface to be inspected, similar to the case of the first embodiment, by performing a process of combining a plurality of obtained captured images. it can.

  With such a configuration, even when it is difficult to illuminate the entire surface of the surface to be inspected Sa because the area where the light from the illumination device 3 can be projected is small, it is appropriate for each inspection object site using the slit light 91. Lighting can be implemented.

<Third Embodiment>
FIG. 11 is a configuration diagram illustrating a main part of the inspection system 1 according to the third embodiment. In FIG. 11, the same code | symbol is attached | subjected about the component similar to the above-mentioned 1st Embodiment. In the third embodiment, items not particularly mentioned below are the same as those in the first embodiment.

  The third embodiment is different from the above-described first embodiment in that illumination is performed using not only visible light but also infrared light or ultraviolet light. As shown in FIG. 11, in addition to the green, red, and blue laser light source devices LG, LR, and LB, the optical engine unit 15 outputs an infrared laser light source device LIR that outputs infrared light and ultraviolet light. An ultraviolet laser light source device LUV is provided. These laser light source devices LIR and LUV can be arranged in the illumination device so as to be guided to the same optical paths as the green, red and blue laser light source devices LG, LR and LB via a required optical system.

  In the inspection system 1 according to the third embodiment, for example, special information is printed on the information display unit 8 for management of the substrate S using fluorescent ink, and the ultraviolet laser light source device LUV is used for the information display unit 8. By projecting an image composed of ultraviolet light, it is possible to read the special information emitted (visualized). It is also possible to inspect the substrate S by configuring the camera 2 to be capable of infrared imaging and projecting an image made of infrared light onto the substrate S by the infrared laser light source device LIR. Thus, by forming an illumination pattern using infrared light or ultraviolet light in addition to visible light, the degree of freedom of the configuration for identifying or visually recognizing the inspection target site on the substrate is increased.

  Although the present invention has been described based on specific embodiments, these embodiments are merely examples, and the present invention is not limited to these embodiments. The configuration of the inspection system according to the present invention can be variously modified. For example, a configuration in which the function of the information processing device is added to a camera or a lighting device is also possible. Moreover, the illumination device for inspection of the present invention is applicable not only for substrate inspection but also for industrial image processing illumination devices for inspection, position recognition, etc., such as displays, solar cells, electronic components, etc. is there. It should be noted that the components of the illumination device for inspection according to the present invention and the inspection system provided with the same according to the present invention shown in the above embodiments are not necessarily all required, and are appropriately selected as long as they do not depart from the scope of the present invention. Is possible.

  The illumination device for inspection according to the present invention and the inspection system equipped with the illumination device appropriately illuminate each inspection target part even when inspecting an inspection target having a plurality of inspection target parts. This makes it possible to shorten the inspection time while maintaining good accuracy, and is useful as an illumination device for inspection and an inspection system including the same.

1 Inspection system 2 Camera (imaging device)
5,6 LSI package (electronic parts)
11 LCD (display device)
12 Input Device 25 Spatial Light Modulator 28 Projection Optical System 74 Image Display Controller (Spatial Light Modulator Controller)
76 Main control unit (trapezoidal distortion correction unit)
82 Image processing units 95a to 95d Photo detector (illuminance sensor)
91 Slit light (band-shaped light)
LB Blue laser light source device LG Green laser light source device LR Red laser light source device LIR Infrared laser light source device LUV Ultraviolet laser light source device S Substrate (inspection object)
Sa surface to be inspected

Claims (8)

  1. A plurality of light source devices that emit light of different colors;
    A spatial light modulator for modulating light from each of the light source devices;
    A projection optical system that projects light from the spatial light modulation element onto the inspection surface of the inspection object;
    A spatial light modulation element controller that forms a projection pattern of light from the projection optical system by controlling the spatial light modulation element according to a predetermined video signal;
    The video signal is generated based on position information of an inspection target part on the inspection surface,
    The illumination device for inspection, wherein the spatial light modulation element control unit forms a projection pattern including an image region corresponding to the inspection target part.
  2.   The illumination device for inspection according to claim 1, wherein the image region corresponding to the inspection target region has a color different from that of an image region corresponding to another region other than the inspection target region.
  3.   The illumination device for inspection according to claim 1 or 2, wherein the inspection object is a substrate, and the inspection object part is an electronic component mounted on the substrate.
  4.   The illumination device for inspection according to any one of claims 1 to 3, wherein the light source device includes a light source device that emits at least one of infrared light and ultraviolet light.
  5. A plurality of illuminance sensors for detecting reflected light illuminance of light of different parts on the surface to be inspected;
    5. The illumination device for inspection according to claim 1, further comprising a trapezoidal distortion correction unit that corrects a trapezoidal distortion of the projection pattern based on a detection result of the illuminance sensor.
  6. The light from the projection optical system is a band-shaped light that crosses the surface to be inspected,
    The illumination device for inspection according to any one of claims 1 to 5, wherein the video signal is changed according to a projection position of the band-shaped light on the surface to be inspected.
  7. An inspection system comprising the inspection illumination device according to any one of claims 1 to 6,
    An imaging device for imaging the surface to be inspected;
    An image processing unit that acquires the position of the examination target part and the position of the image region corresponding to the examination target part by performing image processing of a captured image by the imaging device;
    An inspection system, further comprising: an illumination control unit that generates the video signal so that the position of the inspection target portion acquired by the image processing unit matches the position of the image region.
  8. An inspection system comprising the inspection illumination device according to any one of claims 1 to 6,
    An imaging device for imaging the surface to be inspected;
    A display device for displaying an image captured by the imaging device to an operator;
    An inspection system further comprising an input device for an operator to input information for changing the projection pattern.
JP2011263247A 2011-12-01 2011-12-01 Lighting device for inspection and inspection system having the same Pending JP2013113828A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105025231A (en) * 2014-07-10 2015-11-04 深圳市得意自动化科技有限公司 Photographing method with projection light source and photographing device
JP2017519187A (en) * 2014-04-30 2017-07-13 アトキューブ システムズ アクチエンゲゼルシャフト Interference displacement sensor and semiconductor lithography system incorporated in a machine tool

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017519187A (en) * 2014-04-30 2017-07-13 アトキューブ システムズ アクチエンゲゼルシャフト Interference displacement sensor and semiconductor lithography system incorporated in a machine tool
CN105025231A (en) * 2014-07-10 2015-11-04 深圳市得意自动化科技有限公司 Photographing method with projection light source and photographing device
JP2016017961A (en) * 2014-07-10 2016-02-01 ロテス シェンツェン カンパニー リミテッドLotes Shenzhen Co.,Ltd. Imaging method having projecting light source and imaging apparatus thereof

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