CN107390449A - Lighting device and check device - Google Patents

Abstract

The invention enables the illuminating device to have the illuminating function and the pattern projecting function with a simple device structure. The illuminating device (30) for illuminating the object (O) of the photographing device (20) is configured as follows, and has: a projector (35) for irradiating light; The light from the projector is directed to the subject, and the light from the projector is switched between projected light with a projected pattern and illumination light without a projected pattern. By generating projection light with the projector, it is possible to photograph a projection pattern projected onto the subject, and by generating illumination light with the projector, it is possible to photograph the subject illuminated by the illumination light.

Description

Lighting and inspection devices

technical field

The present invention relates to an illumination device and an inspection device for illuminating an object to be photographed.

Background technique

Currently, as an illumination device for illuminating an object to be photographed by a photographing camera, an illumination device for illuminating an object to be photographed from directly above is known (for example, refer to Patent Document 1). In the lighting device described in Patent Document 1, light is irradiated from a horizontal direction by a surface-emission light source to a half mirror directly under an imaging camera. The direction of light from the light source is reflected directly downward by the half mirror, thereby illuminating the subject from the same direction as the optical axis of the photographing camera. And, the light reflected by the subject is guided to the photographing camera through the half mirror, so that the surface of the subject is photographed by the photographing camera using coaxial epi-illumination.

Patent Document 1: Japanese Patent Laid-Open No. 2014-134525

In recent years, pattern projection using a projector has been required for illuminating a subject as described above. In order to realize pattern projection by the illuminating device, it is necessary to arrange a projector on the same optical path as the light source for coaxial projection, but it is difficult to arrange these light sources and the projector so that they do not interfere with each other. Therefore, it is necessary to separately prepare an imaging device for coaxial illumination and an imaging device for pattern projection, or replace the light source for coaxial projection with a projector for the illumination device, and the device structure of the imaging device becomes complicated. question.

Contents of the invention

The present invention has been made in view of this problem, and an object of the present invention is to provide a lighting device and an inspection device that have a lighting function and a pattern projection function with a simple device structure.

A lighting device according to the present invention, which illuminates an object to be photographed by a photographing device, includes: a projector for irradiating light; and an optical system for guiding the light from the projector to the photographing device. Object, it is possible to switch the light of the projector into projection light with a projected pattern and illumination light without a projected pattern.

According to this configuration, by irradiating projection light with the projection pattern from the projector, it is possible to capture the projection pattern projected onto the subject through the optical system. In addition, by irradiating illumination light without a projected pattern from the projector, imaging can be performed in a state where the subject is illuminated by the illumination light passing through the optical system. As described above, by using a projector as an illumination light source, it is possible to provide an illumination device with an illumination function and a pattern projection function with a simple structure.

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

In the lighting device described above, the projector projects a test chart for calibration of the imaging device as a projection pattern. According to this configuration, calibration is performed using the projected pattern, so that a special tool is not required and cost can be reduced. In addition, it is also easy to change the test pattern.

In the lighting device described above, the projector is a DLP (Digital Light Processing) projector that uniformly reflects light from a light source by all DMD (Digital Micromirror Device) elements, and emits illumination light without a projected pattern. According to this configuration, by controlling the DMD element, it is possible to generate illumination light without a projected pattern and illuminate an object to be photographed.

The inspection device of the present invention is characterized by comprising: the above-mentioned lighting device; an imaging device for imaging an object illuminated by the lighting device; to check the subject. According to this configuration, the inspection device can be provided with a simple device configuration by using the lighting device having the lighting function and the pattern projection function.

The effect of the invention

According to the present invention, by switching and irradiating projection light with a projected pattern and illumination light without a projected pattern by a projector, it is possible to provide an illuminating device with an illuminating function and a pattern projecting function with a simple structure.

Description of drawings

FIG. 1 is a perspective view of an inspection device according to this embodiment.

Fig. 2 is a schematic diagram of a lighting device of a comparative example.

FIG. 3 is a perspective view of the imaging head of this embodiment.

FIG. 4 is a schematic diagram of the lighting device of the present embodiment.

FIG. 5 is an explanatory diagram of a calibration operation and an inspection operation in the present embodiment.

Explanation of labels

1 Inspection device

15 cameras

20 filming device

30 lighting fixtures

35 projectors

37 beam splitter (optical system)

41 light source

43 DMD components

44 DMD controller

50 Controls

detailed description

Next, an inspection device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an inspection device according to this embodiment. In addition, the inspection device of this embodiment is merely an example and can be changed as appropriate.

As shown in FIG. 1 , an inspection device 1 is disposed downstream of a printing device (not shown) or a mounting device (not shown) in a production line, and the inspection device 1 is configured to perform The image processing inspects the printed state of the solder on the substrate W and the mounted state of components. The inspection device 1 may be installed anywhere in the production line, but in the following description, it will be described as an inspection device for inspecting the printed state of solder and the mounted state of components on the substrate W after the reflow process. In the inspection apparatus 1, a substrate transfer device 10 for transferring the substrate W in the X-axis direction is arranged, and the substrate W is positioned at the inspection position by the substrate transfer device 10.

The substrate transfer device 10 forms a transfer path by a pair of conveyor belts 11 for transferring the substrate W and a transfer guide 12 for guiding the transfer of the substrate W along the respective transfer belts 11 . A pair of conveyor belts 11 is mounted on opposite inner surfaces of a pair of conveyance guides 12, and each conveyance guide 12 is supported by a plurality of legs 13 from below. The conveyor belt 11 carries in the substrate W to the inspection position from one end side in the X-axis direction, and carries out the inspected substrate W to the other end side in the X-axis direction. In addition, the upper parts of the pair of conveyance guides 12 are bent inwardly, and the substrate W is moved up and down via the conveyor belt 11 by an elevating mechanism (not shown). Location.

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 illuminates the substrate W to be photographed by the illumination device 30 . W's inspection surface is photographed. 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, for example, a ball screw type driving mechanism or a rack and pinion type driving mechanism. The imaging head 15 is composed of, for example, an imaging element such as a CCD (Charge Coupled Device) sensor, a CMOS (Complementary Metal Oxide Semiconductor) sensor, and an optical system such as a lens.

The illuminating device 30 can illuminate the substrate W from the same direction as the optical axis of the imaging device 20, and can illuminate the substrate W from an oblique direction intersecting the optical axis of the imaging device 20. In this case, the illuminating device 30 is provided with a dome-shaped light-shielding portion 34, and inside the light-shielding portion 34 are provided three types of illuminations 39a-39c (see FIG. 4). In the imaging head 15, by appropriately switching or combining the direction of illumination by the illuminating device 30 corresponding to the solder and components of the inspected portion of the substrate W, the imaging device 20 can obtain a captured image with clear contrast.

The inspection device 1 is provided with a control device 50 for comprehensively controlling each part of the device. The control device 50 is constituted by a processor, a memory, and the like that execute various processes. The memory is composed of one or more storage media such as ROM (Read Only Memory) and RAM (Random Access Memory) according to the application. In addition, an inspection program for the substrate W, a program for calibration (lens correction) of the imaging device 20 described later, and the like are stored in the memory. In the inspection device 1 as described above, the captured image from the imaging device 20 is input to the control device 50, and the control device 50 performs various image processing such as pattern matching, thereby inspecting the substrate W.

In addition, the illumination device 30 requires functions other than illumination, such as a test chart for calibration and a fringe pattern for 3D measurement, as functions other than illumination. As shown in the comparative example of FIG. 2 , in an illumination device 61 for general coaxial illumination, a beam splitter 63 is arranged directly below the imaging device 62 , and a diffusion plate 64 and an illumination substrate are arranged on the side of the beam splitter 63 . 65. In the lighting device 61, the light irradiated from the horizontal direction from the lighting substrate 65 is diffused by the diffuser plate 64 and enters the beam splitter 63. Subject O is illuminated from above.

In order for the lighting device 61 of the comparative example to have a pattern projection function, it is necessary to install a projector 66 on the lighting device 61 through the same optical path as the lighting substrate 65, but the projector 66 cannot be arranged on the optical path of the lighting substrate 65. Therefore, a configuration is conceivable in which an opening is formed in the lighting board 65 , the projector 66 is mounted on the back side of the lighting board 65 , and the projection light from the projector 66 enters the beam splitter 63 through the opening of the lighting board 65 . . However, if the opening is formed in the illumination board 65, the subject O cannot be uniformly illuminated, and there is a problem that uneven brightness occurs.

Therefore, in the lighting device 30 of this embodiment, the light of the projector 35 is switched between projection light with a projected pattern and illumination light without a projected pattern, and not only the light source 41 of the projector 35 (see FIG. 4 ) Used for pattern projection and also as a light source for coaxial epi-illumination. Thus, by irradiating the projection light with the projection pattern, it is possible to project a test chart for calibration and a fringe pattern for 3D measurement. In addition, it is not necessary to provide the illumination board 65 and the diffusion plate 64 in the illumination device 30, and it is possible to uniformly perform coaxial epi-illumination on the subject O with illumination light without a projected pattern.

Next, the lighting device according to this embodiment will be described in detail with reference to Fig. 3 and Fig. 4 . FIG. 3 is a perspective view of the imaging head of this embodiment. Fig. 4 is a schematic diagram of the lighting device of the present embodiment. In addition, the imaging head and the lighting device shown in Fig. 3 and Fig. 4 are merely examples and can be changed as appropriate.

As shown in FIG. 3 , the imaging head 15 is constituted by mounting an imaging device 20 and an illuminating device 30 on the surface of a movable plate 17 movably provided on a moving mechanism (not shown). The device casing of the lighting device 30 is a box-shaped hollow cylindrical casing 31 that is in contact with the lens casing 21 of the imaging device 20, and a beam splitter 37 (see FIG. 4 ) is accommodated under the cylindrical casing 31. The splitter housing 32 is formed. The lens housing 36 of the projector 35 is abutted against one side of the beam splitter housing 32 , and a dome-shaped light shielding device is installed on the surface of the movable plate 17 under the beam splitter housing 32 via a pair of brackets 33 . Section 34.

As shown in FIG. 4 , the lighting device 30 guides the light irradiated from the projector 35 to the subject O through a beam splitter 37 as an optical system, and illuminates the subject O. The projector 35 is a so-called DLP (Digital Light Processing) projector that condenses light from a light source 41 with a condenser lens 42 and is reflected by a plurality of DMD (Digital Micromirror Device) elements 43 to generate projection light and illumination light. The projector 35 is provided with a DMD controller 44 that controls the driving of a plurality 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 the plurality 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. In addition, when the DMD element 43 is controlled to be OFF by the DMD controller 44, the light from the light source 41 is reflected toward a light absorbing plate (not shown) deviated from the projection lens 45 . By locally varying the ON/OFF switching speed of the DMD element 43, light intensity is generated to form a projected pattern.

For example, if a patterned image is input to the DMD controller 44 as an image pattern, the ON/OFF of the plurality of DMD elements 43 are individually controlled to form projected light of a projected pattern according to the light from the light source 41. In addition, if a non-pattern image (no graphic image) is read into the DMD controller 44 as an image pattern, the ON/OFF timings of all the DMD elements 43 are controlled simultaneously so that the light from the light source 41 Forms illuminating light without a projected pattern. At this time, by adjusting the switching speed of ON/OFF, it is possible to adjust the luminance (the amount of light).

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

A spectroscope 37 is accommodated in the spectroscope housing 32, and the light in the horizontal direction from the projector 35 is reflected toward the object O by the spectroscope 37, and the reflected light from the object O is directed toward the imaging device by the spectroscope 37. 20 through. In addition, although the beam splitter 37 is shown as an example of the optical system in this embodiment, any structure that guides the light from the projector 35 to the subject O may be used. For example, instead of the beam splitter 37, a spectroscopic element such as a half mirror or a prism may be used as an optical system, or other optical components such as a lens or a mirror may be used in addition to the spectroscopic element.

Inside the light-shielding portion 34, there are provided an upper layer lighting 39a, a middle layer lighting 39b, and a lower layer lighting 39c that illuminate obliquely with respect to the object O to be photographed. The lighting angles of the upper lighting 39a, the middle lighting 39b, and the lower lighting 39c are different. By appropriately selecting or combining these lightings 39a-39c and the coaxial epi-illumination realized by the projector 35, it is possible to obtain photographs with clear contrast. image. The illuminating device 30 and the imaging device 20 are connected to the control device 50 , and control the inspection process using the coaxial epi-illumination in addition to the calibration using the pattern projection and the like.

In the lighting device 30 configured as described above, the light from the light source 41 of the projector 35 is condensed by the condenser lens 42, irradiated to the plurality of DMD elements 43, and is reflected toward the projection lens 45 by the plurality of DMD elements 43. The light forms projection light and illumination light. At this time, when the image with the pattern is read into the DMD controller 44 , each DMD element 43 is individually controlled, and the projection light with the projection pattern is emitted from the projection lens 45 . In addition, when the non-pattern image is read into the DMD controller 44 , all the DMD elements 43 are uniformly controlled, and the illumination light without the projected pattern is emitted from the projection lens 45 .

The projection light and illumination light transmitted through the projection lens 45 are reflected by the beam splitter 37 in a direction coaxial with the optical axis of the imaging device 20, and are incident on the subject O from directly above. The projected light and the illumination light are reflected by the subject O, and the reflected light passes through the beam splitter 37 and enters the imaging device 20, whereby the subject O is photographed. As mentioned above, by using the projector 35 to generate projected light with a projected pattern and illumination light without a projected pattern, the illuminating device 30 not only has the function of coaxial epi-illumination, but also has the function of pattern projection. In addition, 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, so that a simple device configuration can be achieved.

Next, the calibration operation and the inspection operation will be described with reference to FIG. 5 . Fig. 5 is an explanatory diagram of a calibration operation and an inspection operation in the present embodiment. In addition, the calibration operation and inspection operation shown below are examples and can be changed as appropriate. In addition, the calibration using the projection pattern is described here, but it is also possible to perform 3D measurement using the projection pattern.

As shown in FIG. 5A , during calibration of the imaging device 20, a board P without a pattern is placed as an imaging object 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 to the DMD element 43 through the condenser lens 42, and the light reflected from the DMD element 43 toward the projection lens 45 forms projection light for projecting the test chart for calibration.

The projection light emitted from the projection lens 45 of the projector 35 is reflected by the beam splitter 37, and a test chart is reflected on the surface of the board P to be photographed. When the test chart of the surface of the board P is photographed by the photographing device 20, the photographed image of the test chart is input to the control device 50. Calibration of the imaging device 20 is performed based on the captured image of the test chart in the control device 50 , and distortions such as lens characteristics of the imaging device 20 are corrected. In this way, since calibration is performed using the projected pattern, special tools are not required, and costs can be reduced. In addition, changing the test pattern is also easy by switching the image pattern.

As shown in FIG. 5B , during the inspection of the substrate W, the inspection position of the substrate W as the imaging object 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. In the DMD controller 44, ON/OFF of the DMD element 43 is uniformly controlled corresponding to a white image. Then, the light from the light source 41 of the projector 35 is irradiated to the DMD element 43 through the condensing lens 42, and the light reflected from the DMD element 43 toward the projection lens 45 forms illumination light that does not display a projected pattern. In addition, the DMD element 43 may be controlled to always be ON in order to increase brightness.

The illumination light emitted from the projection lens 45 of the projector 35 is reflected by the beam splitter 37 to illuminate the inspection position of the substrate W which is the imaging object O from directly above. When the inspection position of the substrate W is captured by the imaging device 20 , the captured image of the substrate W is input to the control device 50 . In the control device 50, various image processing such as pattern matching is performed on the captured image of the board W, and the printing state of the solder on the board W and the mounting state of components are inspected. Thereby, without separately providing an illumination light source, illumination light can be generated by the projector 35, and the inspection position of the substrate W can be photographed by coaxial epi-illumination.

As described above, in addition to the test chart for calibration, the fringe pattern for 3D measurement can also be projected on the projector 35 . When the projector 35 is used for 3D measurement, an imaging device is installed inside the light shielding portion 34, etc., so that the projection pattern reflected on the object O is imaged from an oblique direction. In addition, the projector 35 is not limited to calibration and 3D measurement, and can be used for other purposes.

As described above, the illuminating device 30 of the present embodiment can capture the projection pattern projected onto the panel P through the beam splitter 37 by irradiating the projection light with the projection pattern from the projector 35. In addition, by irradiating the illumination light without the projected pattern from the projector 35 , it is possible to image the inspection position of the substrate W while being illuminated by the illumination light passing through the beam splitter 37 . As described above, by using the projector 35 as an illumination light source, the illumination device 30 can be equipped with an illumination function and a pattern projection function with a simple structure.

In addition, the present invention is not limited to the above-described embodiments, and can be implemented with various changes. In the above-described embodiment, the size, shape, etc. shown in the drawings are not limited thereto, and can be appropriately changed within the scope of exerting the effects of the present invention. Moreover, unless it deviates from the scope of the objective of this invention, it can change suitably and implement.

For example, in the present embodiment, the inspection device 1 is configured to include the illumination device 30, but it is not limited to this configuration. The illuminating device 30 may be installed in a processing device that performs imaging processing, or may be included in other processing devices such as a mounting device and a printing device.

In addition, in this 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 the configuration is not limited to this configuration. A configuration in which the projector 35 illuminates from an oblique direction intersecting the optical axis of the imaging device 20 may also be employed.

In addition, in this embodiment, the configuration in which the projector 35 is a DLP projector has been described, but it is not limited to this configuration. The projector 35 may be a projector as long as it can generate 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.

In addition, in the present embodiment, the substrate W is not limited to a printed circuit board as long as it can mount various components, and may be a flexible substrate placed on a tool substrate.

Industrial Applicability

As described above, the present invention has the effect that the lighting function and the pattern projection function can be provided with a simple device structure, especially for the lighting device and the inspection device used in the inspection of the printing state of solder and the mounting state of components. efficient.

Claims (5)

1. A lighting device for illuminating an object to be photographed by a photographing device, The lighting device is characterized in that it has: a projector, which illuminates light; and an optical system that directs light from the projector to the subject, The light of the projector can be switched between projection light with a projected pattern and illumination light without a projected pattern. 2. The lighting device according to claim 1, characterized in that, The optical system guides light from the projector to the subject from a direction coaxial with an optical axis of the photographing device. 3. The lighting device according to claim 1, characterized in that, The projector projects a test chart for calibration of the imaging device as a projection pattern. 4. The lighting device according to claim 1, characterized in that, said projector is a DLP projector, Light from the light source is uniformly reflected by all the DMD elements, and illumination light without a projected pattern is irradiated. 5. An inspection device, characterized in that it has: The lighting device according to any one of claims 1 to 4; a photographing device that photographs a subject illuminated by the lighting device; and A control device for inspecting an object to be photographed based on a photographed image photographed by the photographing device.