JP2017207329A - Illumination device and inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination device with an illumination function and a pattern projection function by a simple device configuration.SOLUTION: An illumination device (30) for illuminating an imaging object (O) of an imaging device (20) includes a projector (35) for emitting light and a splitter (37) for guiding the light from the projector to the imaging object, and is configured to switch the light from the projector between projected light with a projection pattern and illumination light without a projection pattern. Creating projected light by the projector can take an image of a projection pattern projected on a projection object, and creating illumination light by the projector can take an image of the object being irradiated with the illumination light.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an illumination device and an inspection device that illuminate an imaging target.

  2. Description of the Related Art Conventionally, an illumination device that illuminates an imaging target of an imaging camera is known that illuminates the imaging target from directly above (see, for example, Patent Document 1). In the illumination device described in Patent Document 1, light is irradiated from a horizontal direction to a half mirror directly below the imaging camera by a surface-emitting light source. The direction of the light from the light source is reflected directly downward by the half mirror, so that the imaging target is illuminated from the same direction as the optical axis of the imaging camera. Then, the light reflected by the imaging target passes through the half mirror and is guided to the imaging camera, whereby the surface of the imaging target is imaged by the imaging camera using coaxial incident illumination.

JP 2014-134525 A

  In recent years, pattern illumination using a projector has been required for such illumination of an imaging target. In order to realize pattern projection by the illumination device, it is necessary to arrange a projector on the same optical path as the coaxial incident light source. However, it is difficult to arrange the light source and the projector so as not to interfere with each other. For this reason, an imaging device for coaxial illumination and an imaging device for pattern projection must be prepared separately, or the projector must be replaced with a lighting device instead of a coaxial incident light source. There was a problem that the configuration was complicated.

  This invention is made | formed in view of this point, and it aims at providing the illuminating device and inspection apparatus which were equipped with the illumination function and the pattern projection function with the simple apparatus structure.

  An illuminating device of the present invention is an illuminating device that illuminates an imaging target of an imaging device, and includes a projector that irradiates light and an optical system that guides light from the projector to the imaging target. It is possible to switch between projection light with a projection pattern and illumination light without a projection pattern.

  According to this configuration, the projection pattern projected onto the imaging target can be imaged through the optical system by irradiating the projection light with the projection pattern from the projector. Further, by irradiating illumination light without a projection pattern from the projector, it is possible to capture an image with the imaging target illuminated by the illumination light through the optical system. Thus, by using the projector as an illumination light source, the illumination device can have an illumination function and a pattern projection function with a simple configuration.

  In the illumination device, the optical system guides light from the projector to the imaging target from a direction coaxial with the optical axis of the imaging device. According to this configuration, the illumination device can be provided with the coaxial epi-illumination function and the pattern projection function with a simple configuration.

  In the illumination device, the projector projects a test chart for calibration of the imaging device as a projection pattern. According to this configuration, since the calibration is performed using the projection pattern, a dedicated jig is not necessary and the cost can be reduced. In addition, it is easy to change the test chart.

  In the above illumination device, the projector is a DLP (Digital Light Processing) projector, and all DMD (Digital Micromirror Device) elements uniformly reflect light from a light source to irradiate illumination light without a projection pattern. According to this configuration, it is possible to illuminate the imaging target by generating illumination light without a projection pattern by controlling the DMD element.

  An inspection apparatus of the present invention includes the above-described illumination device, an imaging device that captures an imaging target illuminated by the illumination device, and a control device that inspects the imaging target based on a captured image captured by the imaging device. It is characterized by that. According to this structure, an inspection apparatus can be made into a simple apparatus structure with the illuminating device provided with the illumination function and the pattern projection function.

  According to the present invention, an illumination device can have an illumination function and a pattern projection function with a simple configuration by switching and irradiating projection light with a projection pattern and illumination light without a projection pattern by a projector. it can.

It is a perspective view of the inspection apparatus of this Embodiment. It is a schematic diagram of the illuminating device of a comparative example. It is a perspective view of the imaging head of this embodiment. It is a schematic diagram of the illuminating device of this Embodiment. It is explanatory drawing of the calibration operation | movement and test | inspection operation | movement of this Embodiment.

  Hereinafter, the inspection apparatus of the present embodiment will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of the inspection apparatus according to the present embodiment. In addition, the inspection apparatus of this Embodiment is only an example, and can be changed suitably.

  As shown in FIG. 1, the inspection apparatus 1 is disposed downstream of a printing apparatus (not shown) or a mounting apparatus (not shown) in the production line, performs image processing on a captured image captured by the imaging head 15, and The printed state of solder on W and the mounting state of components are inspected. The inspection apparatus 1 may be disposed at any position on the production line. However, in the following description, the inspection apparatus 1 is described as inspecting the printed state of solder and the mounted state of components after the reflow processing on the substrate W. The inspection apparatus 1 is provided with a substrate transport apparatus 10 that transports the substrate W in the X-axis direction, and the substrate transport apparatus 10 positions the substrate W at the inspection position.

  The substrate transport apparatus 10 forms a transport path by a pair of conveyors 11 that transport the substrate W and a transport guide 12 that guides the transport of the substrate W along each conveyor 11. The pair of conveyors 11 are attached to the opposing inner surfaces of the pair of conveyance guides 12, and each conveyance guide 12 is supported from below by a plurality of legs 13. The conveyor 11 carries the substrate W into the inspection position from one end side in the X-axis direction, and carries out the substrate W after inspection to the other end side in the X-axis direction. Moreover, the upper part of a pair of conveyance guide 12 is bent inward, the board | substrate W is moved up and down via the conveyor 11 by a raising / lowering mechanism (not shown), and the board | substrate W is pressed by this bending part, and the board | substrate W is pressed. Is positioned at the inspection position.

  The imaging head 15 is positioned above the substrate W positioned at the inspection position by a moving mechanism (not shown), and the imaging device 20 inspects the substrate W while the substrate W is illuminated by the illumination device 30 to be imaged. Image the surface. The moving mechanism of the imaging head 15 is configured to horizontally move the imaging head 15 in the X-axis direction and the Y-axis direction, and is configured by, for example, a ball screw type driving mechanism or a rack and pinion type driving mechanism. . The imaging head 15 includes, for example, an imaging element such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor and an optical system such as a lens.

  The illumination device 30 can illuminate the substrate W from the same direction as the optical axis of the imaging device 20 and illuminate the substrate W from an oblique direction intersecting with the optical axis of the imaging device 20. In this case, the illumination device 30 is provided with a dome-shaped shade 34, and three types of illuminations 39a to 39c (see FIG. 4) having different irradiation angles with respect to the inspection surface of the substrate W are provided inside the shade 34. Yes. In the imaging head 15, an imaging image with a clear contrast can be obtained by the imaging device 20 by appropriately switching or combining the illumination directions by the illumination device 30 in accordance with the solder and components at the inspection location of the substrate W. Yes.

  The inspection device 1 is provided with a control device 50 that performs overall control of each part of the device. The control device 50 includes a processor that executes various processes, a memory, and the like. The memory is composed of one or a plurality of storage media such as a ROM (Read Only Memory) and a RAM (Random Access Memory) depending on the application. Further, the memory stores an inspection program for the substrate W, a calibration (lens correction) program for the imaging apparatus 20 described later, and the like. In such an inspection apparatus 1, a captured image from the imaging apparatus 20 is input to the control apparatus 50, and the substrate W is inspected by performing various image processing such as pattern matching in the control apparatus 50.

  By the way, the illumination device 30 is required to have functions other than illumination, such as a calibration test chart and a 3D measurement stripe pattern, as functions other than illumination. As shown in the comparative example of FIG. 2, in a general illumination device 61 for coaxial illumination, a splitter 63 is disposed directly below the imaging device 62, and a diffusion plate 64 and an illumination substrate 65 are disposed on the side of the splitter 63. ing. In the illuminating device 61, light from the horizontal direction from the illuminating substrate 65 is diffused by the diffusion plate 64 and enters the splitter 63, and the light is reflected by the splitter 63 in the same direction as the optical axis of the imaging device 62, so The imaging object O is illuminated.

  In order to give the illumination device 61 of the comparative example a pattern projection function, it is necessary to attach the projector 66 to the illumination device 61 so as to pass through the same optical path as the illumination substrate 65. However, the projector 66 is placed on the optical path of the illumination substrate 65. Cannot be placed. For this reason, a configuration is conceivable in which an opening is made with respect to the illumination board 65, a projector 66 is attached to the back side of the illumination board 65, and projection light from the projector 66 enters the splitter 63 through the opening of the illumination board 65. However, if an opening is formed in the illumination board 65, there is a problem that the imaging object O cannot be illuminated uniformly and uneven brightness occurs.

  Therefore, in the illumination device 30 according to the present embodiment, the light of the projector 35 is switched between the projection light with the projection pattern and the illumination light without the projection pattern, and the light source 41 (see FIG. 4) of the projector 35 is simply projected. It is used as a light source for coaxial epi-illumination. Thereby, a test chart for calibration and a fringe pattern for 3D measurement can be projected by irradiating projection light with a projection pattern. Further, the imaging object O (see FIG. 4A) can be uniformly and coaxially illuminated with illumination light having no projection pattern without providing the illumination substrate 65 or the diffusion plate 64 in the illumination device 30.

  Hereinafter, with reference to FIG.3 and FIG.4, the illuminating device of this Embodiment is demonstrated in detail. FIG. 3 is a perspective view of the imaging head of the present embodiment. FIG. 4 is a schematic diagram of the lighting device of the present embodiment. Note that the imaging head and the illumination device in FIGS. 3 and 4 are merely examples, and can be changed as appropriate.

  As shown in FIG. 3, the imaging head 15 is configured by attaching an imaging device 20 and an illumination device 30 to the surface of a movable plate 17 that is movably installed in a moving mechanism (not shown). The device case of the illumination device 30 includes a hollow cylindrical case 31 that contacts the lens case 21 of the imaging device 20, and a box-type splitter case 32 that houses a splitter 37 (see FIG. 4) below the cylindrical case 31. It is formed with. A lens case 36 of the projector 35 is brought into contact with one side surface of the splitter case 32, and a dome-like shade 34 is attached to the surface of the movable plate 17 via a pair of brackets 33 below the splitter case 32.

  As shown in FIG. 4, the illumination device 30 illuminates the imaging target O by guiding the light emitted from the projector 35 to the imaging target O through a splitter 37 as an optical system. The projector 35 is a so-called DLP (Digital Light Processing) projector, which condenses the light from the light source 41 by a condenser lens 42 and reflects it by a large number of DMD (Digital Micromirror Device) elements 43 to project light or illumination light. Is producing. The projector 35 is provided with a DMD controller 44 that controls driving of a large number of DMD elements 43, and the driving of the DMD elements 43 is controlled in accordance with an image pattern input to the DMD controller 44.

  By reading the image pattern into the DMD controller 44, a projection pattern corresponding to the image pattern is formed by a large number of DMD elements 43. Specifically, when the DMD element 43 is controlled to be ON by the DMD controller 44, the light from the light source 41 is reflected toward the projection lens 45. Further, when the DMD controller 44 controls the DMD element 43 to be turned off, the light from the light source 41 is reflected toward a light absorbing plate (not shown) that is out of the projection lens 45. A projection pattern is formed by partially varying the ON / OFF switching speed of the DMD element 43 to create light shading.

  For example, when an image with a pattern is input to the DMD controller 44 as an image pattern, projection light with a projection pattern is formed from the light of the light source 41 by individually controlling ON / OFF of a large number of DMD elements 43. When an image without a pattern (a plain image) is read by the DMD controller 44 as an image pattern, the illumination without a projection pattern is generated from the light from the light source 41 by simultaneously controlling the ON / OFF timings of all the DMD elements 43. Light is formed. At this time, it is possible to adjust the luminance (light quantity) by adjusting the ON / OFF switching speed.

  The projector 35 is provided with a slot 46 for an external storage medium such as a USB memory or an SD card. An external storage medium is mounted in the slot 46 of the projector 35, and an image pattern in the external storage medium is read into the DMD controller 44 to control the DMD element 43. The image pattern is not limited to the configuration read from the external storage medium, and may be prepared in the internal memory of the DMD controller 44 or may be input from an external device by wireless communication or wired communication. Moreover, it is also possible to form colored projection light and illumination light by transmitting light from the light source 41 through the color wheel.

  A splitter 37 is accommodated in the splitter case 32, and the light in the horizontal direction from the projector 35 is reflected toward the imaging target O by the splitter 37 and the reflected light from the imaging target O is reflected by the splitter 37. Permeate toward. In the present embodiment, the splitter 37 is exemplified as the optical system, but any configuration that guides the light from the projector 35 to the imaging target O may be used. For example, a spectroscopic element such as a half mirror or a prism may be used instead of the splitter 37 as the optical system, or another optical member such as a lens or a mirror may be used in addition to the spectroscopic element.

  Inside the shade 34, an upper stage illumination 39a, a middle stage illumination 39b, and a lower stage illumination 39c that irradiate the imaging target O obliquely are provided. The upper illumination 39a, the middle illumination 39b, and the lower illumination 39c have different illumination angles, and a captured image with clear contrast can be obtained by appropriately selecting or combining these illumination 39a-illumination 39c and the coaxial incident illumination by the projector 35. Is possible. The illumination device 30 and the imaging device 20 are connected to the control device 50, and in addition to controlling calibration and the like using pattern projection, the inspection processing using coaxial epi-illumination is controlled.

  In the illuminating device 30 configured as described above, the light from the light source 41 of the projector 35 is condensed by the condenser lens 42 and applied to the multiple DMD elements 43, and directed to the projection lens 45 by the multiple DMD elements 43. Projection light and illumination light are formed by the reflected light. At this time, when a pattern-equipped image is read into the DMD controller 44, each DMD element 43 is individually controlled, and projection light having a projection pattern is emitted from the projection lens 45. When a patternless image is read in the DMD controller 44, all DMD elements 43 are uniformly controlled, and illumination light without a projection pattern is emitted from the projection lens 45.

  Further, the projection light and the illumination light transmitted through the projection lens 45 are reflected by the splitter 37 in the direction coaxial with the optical axis of the imaging device 20 and are incident on the imaging target O from directly above. Projection light and illumination light are reflected by the imaging target O, and the reflected light passes through the splitter 37 and enters the imaging device 20, whereby the imaging target O is imaged. As described above, the projector 35 generates the projection light with the projection pattern and the illumination light without the projection pattern, so that the illumination apparatus 30 has the pattern projection function simultaneously with the coaxial epi-illumination function. Moreover, since the projection light at the time of pattern projection and the illumination light at the time of coaxial epi-illumination pass through the same optical path, a simple device configuration can be achieved.

  Next, the calibration operation and the inspection operation will be described with reference to FIG. FIG. 5 is an explanatory diagram of the calibration operation and the inspection operation of the present embodiment. Note that the calibration operation and the inspection operation described below are examples, and can be appropriately changed. In addition, although the calibration using the projection pattern is described here, 3D measurement can also be performed using the projection pattern.

  As shown in FIG. 5A, during calibration of the imaging device 20, a plain plate P is placed as the imaging target O within the imaging range of the imaging device 20, and a test chart image is read into the DMD controller 44. In the DMD controller 44, ON / OFF of the DMD element 43 is individually controlled according to the test chart image. Then, the light from the light source 41 of the projector 35 is irradiated onto the DMD element 43 through the condenser lens 42, and the projection light that projects the calibration test chart is reflected by the light reflected from the DMD element 43 toward the projection lens 45. It is formed.

  The projection light emitted from the projection lens 45 of the projector 35 is reflected by the splitter 37, whereby a test chart is projected on the surface of the plate P as an imaging target. When a test chart on the surface of the plate P is imaged by the imaging device 20, a captured image of the test chart is input to the control device 50. The control device 50 calibrates the imaging device 20 based on the captured image of the test chart, and corrects distortion such as lens characteristics of the imaging device 20. Thereby, since the calibration is performed using the projection pattern, a dedicated jig is not necessary and the cost can be reduced. Moreover, the test chart can be easily changed by replacing the image pattern.

  As shown in FIG. 5B, at the time of inspection of the substrate W, the inspection position of the substrate W as the imaging target O is positioned within the imaging range of the imaging device 20, and a white image without a pattern is read into the DMD controller 44. The DMD controller 44 uniformly controls ON / OFF of the DMD element 43 according to the white image. Then, the light from the light source 41 of the projector 35 is irradiated to the DMD element 43 through the condenser lens 42, and illumination light that does not display the projection pattern is formed by the light reflected from the DMD element 43 toward the projection lens 45. Note that the DMD element 43 may be always controlled to be ON in order to increase the luminance.

  The illumination light emitted from the projection lens 45 of the projector 35 is reflected by the splitter 37, so that the inspection position of the substrate W as the imaging object O is illuminated from directly above. When the inspection position of the substrate W is imaged by the imaging device 20, the captured image of the substrate W is input to the control device 50. Various image processing such as pattern matching is performed on the captured image of the substrate W in the control device 50 to inspect the printed state of solder on the substrate W and the mounting state of components. Thereby, an illumination light can be created by the projector 35 without separately providing an illumination light source, and the inspection position of the substrate W can be imaged by the coaxial incident illumination.

  As described above, the projector 35 can project a 3D measurement fringe pattern in addition to the calibration test chart. When the projector 35 is used for 3D measurement, an imaging device is attached inside the shade 34 or the like so that the projection pattern projected on the imaging target O is imaged from an oblique direction. The projector 35 can be used not only for calibration and 3D measurement but also for other purposes.

  As described above, the illumination device 30 according to the present embodiment can capture the projection pattern projected onto the plate P through the splitter 37 by irradiating the projection light with the projection pattern from the projector 35. Further, by irradiating illumination light without a projection pattern from the projector 35, it is possible to take an image while the inspection position of the substrate W is illuminated with illumination light through the splitter 37. Thus, by using the projector 35 as an illumination light source, the illumination device 30 can have an illumination function and a pattern projection function with a simple configuration.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the present embodiment, the inspection device 1 is configured to include the illumination device 30, but is not limited to this configuration. The illumination device 30 only needs to be included in a processing device that performs an imaging process, and may be included in another processing device such as a mounting device or a printing device, for example.

  Further, in the present embodiment, the projector 35 is configured to perform coaxial epi-illumination from the same direction as the optical axis of the imaging device 20, but is not limited to this configuration. The projector 35 may be configured to illuminate from an oblique direction that intersects the optical axis of the imaging device 20.

  In the present embodiment, the configuration in which the projector 35 is a DLP projector has been described. However, the configuration is not limited to this configuration. The projector 35 may be any projector that can form illumination light in addition to projection light, and may be, for example, an LCD (Liquid Crystal Display) projector or an LCOS (Liquid Crystal On Silicon) projector.

  Moreover, in this Embodiment, the board | substrate W should just be what can mount various components, and is not limited to a printed circuit board, The flexible board mounted on the jig | tool board | substrate may be sufficient.

  As described above, the present invention has an effect that it is possible to provide an illumination function and a pattern projection function with a simple apparatus configuration, and in particular, illumination used for inspection of a solder printing state and a component mounting state. Useful for devices and inspection devices.

DESCRIPTION OF SYMBOLS 1 Inspection apparatus 15 Imaging head 20 Imaging apparatus 30 Illumination apparatus 35 Projector 37 Splitter (optical system)
41 Light source 43 DMD element 44 DMD controller 50 Control device

Claims (5)

An illumination device that illuminates an imaging target of an imaging device,
A projector that emits light;
An optical system that guides light from the projector to the imaging target,
An illumination device characterized in that the light of the projector can be switched between projection light with a projection pattern and illumination light without a projection pattern.   The illumination device according to claim 1, wherein the optical system guides light from the projector to the imaging target from a direction coaxial with an optical axis of the imaging device.   The lighting device according to claim 1, wherein the projector projects a test chart for calibration of the imaging device as a projection pattern. The projector is a DLP (Digital Light Processing) projector;
4. The illumination apparatus according to claim 1, wherein all DMD (Digital Micromirror Device) elements uniformly irradiate light from a light source and irradiate illumination light without a projection pattern. The lighting device according to any one of claims 1 to 4,
An imaging device for imaging an imaging target illuminated by the illumination device;
An inspection apparatus comprising: a control apparatus that inspects an imaging target based on a captured image captured by the imaging apparatus.

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