JP2014130130A - Inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel inspection apparatus.SOLUTION: The inspection apparatus includes an illuminating device irradiating an object to be picked up with light, an imaging apparatus receiving the light reflected from the object to be picked up based on the irradiation with the light, and an imaging element existing in the imaging apparatus and receiving the reflected light. The inspection apparatus is the inspection apparatus acquiring one or both of the two-dimensional image and three-dimensional image of the object to be picked up. An imaging area is provided in the imaging element. The imaging area receives the reflected light. Further, a bandpass filter is provided on the imaging area.

Description

  The present invention relates to a novel inspection apparatus.

An example of the inspection apparatus is a solder printing inspection apparatus.
Regarding a solder printing inspection apparatus, for example, in Patent Document 1, red (hereinafter referred to as “R”), green (hereinafter referred to as “G”), blue (hereinafter referred to as “B”) in order to acquire a two-dimensional image. .) LED light is used, and laser light is used to acquire a three-dimensional image. By preparing and scanning an imaging area for each of the LED light and laser light, the two-dimensional image and the three-dimensional image are simultaneously acquired, and the two-dimensional image and the three-dimensional image are simultaneously inspected.

  As one of means for realizing the solder printing inspection apparatus of Patent Literature 1, the line illumination device of Patent Literature 2 can be used. This line illumination device irradiates the R, G, and B colors for acquiring a two-dimensional image so that the R, G, and B colors do not interfere with the imaging range of the imaging target corresponding to the imaging area of the imaging device. doing.

  As described above, in Patent Document 1, it is necessary to irradiate illumination light to the imaging range of the imaging target. Therefore, the illumination device of Patent Document 2 is used to irradiate illumination light to each of the imaging ranges of the imaging target. These illumination lights are condensed using an optical system so as not to interfere with each other to form line lights.

JP 2011-089939 A JP 2011-145229 A

  However, in the conventional inspection apparatus described above, it is difficult to distinguish from the pad or solder depending on the brightness at the irradiation surface, at the edge of the notch portion of the solder resist, from the directivity of the illumination of the solder printing inspection apparatus. An area may occur, and the measurement of the amount of solder becomes unstable.

  In both LED line illumination and ring illumination, there may be a region where it is difficult to identify whether the solder is solder or not on the surface of the flux that has oozed out of the solder during solder imaging.

  In addition to the above-mentioned problem that the region that is difficult to identify becomes a noise component in image processing, in the inspection of leveled substrates, the silver pad and silver solder are used for normal ring illumination, line illumination, and vertical epi-illumination. In this case, images with the same brightness and hue may be captured, resulting in regions that are difficult to identify. In this case, there is a problem that it is difficult to measure the amount of solder.

  In the solder printing inspection apparatus, the presence of the edge of the notch portion of the solder resist and the blur of the flux always exist due to the characteristics of the product to be inspected, and there is a need to measure the amount of solder on the leveled substrate.

  On the other hand, in Patent Document 1, in order to prevent illumination light of other colors (wavelengths) from interfering with the imaging range of the imaging target and to reduce the irradiation dead angle, the illumination illumination method uses line-shaped illumination light before and after Irradiation from two directions. However, in the case of the irradiation light from the two directions of the line shape, there is a problem in that the irradiation is not complete, but the irradiation blind spot is locally generated near the joint of the front and rear illumination.

  In addition, when a color image is captured, since the reflectance of the imaging target is partially different, a region that is difficult to identify may occur, or a portion that is dark and does not appear may occur. As a countermeasure, there is a method of capturing an image twice or more by changing the exposure time and complementing a dark portion or a region that is difficult to identify. However, this method has a problem that it takes two or more scanning times and also requires switching between illumination illuminance and exposure time, resulting in an imaging tact.

  Conventionally, when acquiring both a polarized image and a non-polarized image, it is necessary to switch the optical system between acquiring the polarized image and acquiring the non-polarized image before and after switching. There is a problem that an imaging tact time is required due to an imaging time and an operation time that are twice or more of the above.

  Note that the polarization image is an image captured under a condition in which the polarization direction of the illumination polarizer and the polarization direction of the imaging lens analyzer are perpendicular to each other. In addition, a non-polarized image is a condition in which the polarization direction of the polarizer of the illumination and the polarization direction of the analyzer of the imaging lens are perpendicular to each other, or a polarizer or an analyzer on one or both of the illumination and the imaging lens. It is the image imaged on the conditions which do not use.

Therefore, development of a new inspection apparatus that solves such problems is desired.
This invention is made | formed in view of such a subject, and it aims at providing a novel test | inspection apparatus.

  In order to solve the above-described problems and achieve the object of the present invention, an inspection apparatus of the present invention receives an illumination device that irradiates light to an imaging target, and reflected light from the imaging target based on the irradiation of the light. In an inspection apparatus that has an imaging device that performs imaging, and an imaging device that is present in the imaging device and receives the reflected light, and that acquires one or both of the two-dimensional image and the three-dimensional image of the imaging target The imaging device is provided with an imaging region, the imaging region receives the reflected light, and a band pass filter is provided on the imaging region.

The present invention has the following effects.
The inspection apparatus of the present invention is present in the illumination apparatus that irradiates light to the imaging target, the imaging apparatus that receives reflected light from the imaging target based on the irradiation of the light, and the imaging apparatus, An inspection device that receives reflected light, and obtains one or both of a two-dimensional image and a three-dimensional image of the imaging target, wherein the imaging device is provided with an imaging region, Since the reflected light is received and a band-pass filter is provided on the imaging region, a novel inspection device can be provided.

1 is a perspective view showing an overall configuration of a solder printing inspection apparatus, which is an example of an inspection apparatus according to an embodiment of the present invention. It is a figure which shows the image pick-up element in which the two-dimensional imaging area and the three-dimensional imaging area were set. It is a figure which shows the polarization illumination optical system of LED light in the test | inspection apparatus of this invention. It is a figure which shows the polarization illumination optical system of the laser beam in the test | inspection apparatus of this invention. It is the photograph and figure explaining the example of application with respect to the hard-to-recognize area | region resulting from the transparent substance or semi-transparent substance contained in solder. It is the photograph and figure explaining the example of application with respect to the hard-to-identify area | region which may generate | occur | produce in the place where the thickness of the soldering resist provided on the board | substrate changes rapidly. It is the photograph and figure explaining the example of application with respect to the hard-to-identify area | region which may generate | occur | produce between the surface of the metal for mounting components, and the surface of solder. It is the figure which provided the imaging area | region which carried out the scanning line shape on the CMOS sensor. FIG. 6 is a diagram in which line-shaped illumination light is irradiated from two front and rear directions. It is the figure which coated the band pass filter of multiple wavelengths on the glass window. It is the figure which installed the glass window of FIG. 10 so that a band pass filter might cover each imaging region. It is a figure explaining the irradiation system which may interfere with another imaging area | region is attained, and it can be set as the perimeter irradiation system which irradiates the whole surface of an imaging visual field. It is a figure of the image pick-up element which has an imaging region matched with the illumination group of R1, G1, B1, and the illumination group of R2, G2, B2. It is a figure which shows an illuminating device and an experimental result. It is a figure of the image pick-up element which has an imaging region matched with the illumination group of R1, G1, B1, and the illumination group of R2, G2, B2. It is a figure of the apparatus which installs a polarizer between an illuminating device and an imaging target, and installs an analyzer between an imaging lens and an imaging target. It is a figure of the image pick-up element which can acquire simultaneously the data of the image polarized by one scan, and the data of the image which is not polarized. It is a figure which shows one example of the test | inspection apparatus of this invention.

Hereinafter, modes for carrying out the present invention will be described.
First, the form for implementing 1st invention concerning a test | inspection apparatus is demonstrated.
The inspection apparatus of the present invention is present in the illumination apparatus that irradiates light to the imaging target, the imaging apparatus that receives reflected light from the imaging target based on the irradiation of the light, and the imaging apparatus, And an imaging device that receives reflected light, and a polarizer is installed between the illumination device and the imaging target in an inspection apparatus that acquires one or both of a two-dimensional image and a three-dimensional image of the imaging target In addition, the inspection apparatus is an inspection apparatus in which an analyzer is installed between the imaging target and the imaging apparatus to suppress the occurrence of a difficult-to-identify region in one or both of the two-dimensional image and the three-dimensional image.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an overall configuration of a solder printing inspection apparatus, which is an example of an inspection apparatus according to an embodiment of the present invention. The solder printing inspection apparatus 1 has a function of inspecting solder by performing two-dimensional measurement and three-dimensional measurement of cream solder (hereinafter referred to as “solder”) printed on a substrate 100 to be imaged. . The solder printing inspection apparatus 1 includes an illumination device 2, an imaging device 3, a control device 4, a table 5, and the like.

  The lighting device 2 includes two three-dimensional line lighting devices 10a and 10b and six two-dimensional line lighting devices 20a, 20b, 30a, 30b, 40a, and 40b. The imaging device 3 includes a camera 50 and an imaging lens 60 that capture black and white images. The camera 50 includes an image sensor 51 of a CMOS sensor. The control device 4 includes an image processing control unit 70. The image processing control unit 70 includes a three-dimensional imaging region image memory 71a for the three-dimensional line illumination device 10a, a three-dimensional imaging region image memory 71b for the three-dimensional line illumination device 10b, and a two-dimensional line illumination device 20a. , 20b two-dimensional imaging region image memory 72, two-dimensional line illumination devices 30a, 30b two-dimensional imaging region image memory 73, two-dimensional line illumination devices 40a, 40b two-dimensional imaging region images. A memory 74 is provided. The table 5 includes an X-axis table 80, an X-axis motor 81, a Y-axis table 82, and a Y-axis motor 83.

The two-dimensional line illumination device irradiates light onto the substrate 100 that is an imaging target. The two-dimensional line illumination devices 20a and 20b are arranged so as to sandwich an optical system composed of the camera 50 and the imaging lens 60, and the two-dimensional line illumination devices 21a and two-dimensional line illumination light 21a of the two-dimensional line illumination device 20a are arranged. The two-dimensional line illumination light 21b of the line illumination device 20b is projected obliquely downward from the upper direction, whereby a two-dimensional line illumination light trace 21 is generated on the substrate 100. The two-dimensional line illumination devices 30 a and 30 b and the two-dimensional line illumination devices 40 a and 40 b are similarly arranged and projected, so that two-dimensional line illumination light traces 31 and 41 are generated on the substrate 100.
A polarizer is installed between each of the two-dimensional line illumination devices 20a, 20b, 30a, 30b, 40a, and 40b and the substrate 100 (not shown).

  For example, a red light source is used for the two-dimensional line illumination devices 20a and 20b, and a green light source is used for the two-dimensional line illumination devices 30a and 30b. For example, a blue light source is adopted as 40b.

The three-dimensional line illumination device irradiates light onto the substrate 100 that is an imaging target. The three-dimensional line illumination devices 10a and 10b are arranged in such a manner as to sandwich an optical system composed of the camera 50 and the imaging lens 60, and each project light from an upper direction to an obliquely downward direction, thereby three-dimensional use. Line illumination lights 11 a and 11 b are generated, and three-dimensional line illumination light traces 12 a and 12 b are generated on the substrate 100.
Polarizers are installed between the three-dimensional line illumination devices 10a and 10b and the substrate 100 (not shown).

  The three-dimensional line illumination devices 10a and 10b employ a red light source or a blue / green light source according to the hue of the substrate 100.

The imaging device 3 receives reflected light from the substrate 100 based on irradiation light. The imaging element 51 is present in the imaging device 3 and receives reflected light. The two-dimensional line illumination light traces 21, 31, 41 and the three-dimensional line illumination light traces 12 a, 12 b generated on the substrate 100 are projected onto the imaging element 51 of the camera 50 through the imaging lens 60.
An analyzer is installed between the substrate 100 and the imaging device 3 (not shown).

  As shown in FIG. 2, the imaging element 51 can arbitrarily set the imaging area, and the two-dimensional imaging areas 53, 54, 55 for imaging the two-dimensional line illumination light traces 21, 31, 41. In addition, five areas of three-dimensional imaging areas 52a and 52b for imaging the three-dimensional line illumination light traces 12a and 12b are set. The two-dimensional imaging areas 53, 54, and 55 have an imaging width of one pixel and can be regarded as equivalent to a line sensor camera. The three-dimensional imaging regions 52a and 52b have a relatively large value because the imaging width defines the maximum measurement height, and are usually about 40 to 50 pixels.

  With the above optical system / illumination system configuration, the X axis table 80 is moved at a constant pitch to capture an image with the camera 50, and the X axis table 80 is moved at a constant pitch to capture an image with the camera 50. During the operations described above, a plane image can be obtained by accumulating outputs from the two-dimensional imaging area in the corresponding two-dimensional imaging area image memories 72, 73, 74, respectively. In addition, the plane image output from the three-dimensional imaging region is accumulated in the corresponding three-dimensional imaging region image memories 71a and 71b.

  In addition, the three-dimensional imaging region image memories 71a and 71b in which a large number of surface images are accumulated can reproduce the uneven state of the surface to be measured, so that a three-dimensional solder inspection can be performed.

  That is, the three-dimensional line illumination light traces 12a and 12b on the solder and the three-dimensional line illumination light traces 12a and 12b on the substrate 100 are imaged so that their positions are shifted by the height of the solder. Assuming that the attachment angle of the three-dimensional line illumination lights 11a and 11b from the upper surface of the substrate 100 is θ, the solder height can be measured by multiplying the amount of solder displacement by tan θ. Furthermore, the volume of solder can be measured by similarly obtaining the direction orthogonal to the length direction of the three-dimensional line illumination light traces 12a and 12b.

As described above, there is no distinction between the two-dimensional inspection and the three-dimensional inspection in the optical system of the camera 50 and the imaging lens 60, and the image pickup is repeated by moving the X axis table 80 by a constant pitch and picking up an image with the camera 50. It is possible to collect two-dimensional images and three-dimensional images and to perform two-dimensional inspections and three-dimensional inspections by performing only one scan. Inspection is fully integrated.
Note that the inspection apparatus is not limited to acquiring both a two-dimensional image and a three-dimensional image to be imaged. The inspection apparatus can also acquire only one of the two-dimensional image and the three-dimensional image to be imaged.

  The polarization illumination optical system for LED light in the inspection apparatus of the present invention will be described with reference to FIG. A polarizing filter, which is a polarizer, is attached to the lighting device side to polarize the illumination light. The light transmitted through the polarizer becomes linearly polarized light that vibrates in the direction of the transmission axis of the polarizer. On the other hand, a polarizing filter as an analyzer is attached to the imaging lens side, and when the polarized light irradiated from the illumination device is reflected by the imaging target and the reflected polarized light reaches the analyzer, the vibration direction of the reflected polarized light is the analyzer. It is attached so as to be perpendicular to the transmission axis of, i.e., to cross.

A polarization illumination optical system for laser light in the inspection apparatus of the present invention will be described with reference to FIG. Ordinary laser light has the same vibration direction. The vibration direction can be arbitrarily set with respect to the direction of the line light. FIG. 4 is a diagram in which the laser beam oscillates in a direction perpendicular to the direction of the laser line beam. The transmission axis of the polarizing filter, which is the analyzer on the imaging lens side, is attached so as to be perpendicular to the vibration direction of the laser light in FIG. Thus, the polarization illumination optical system for laser light is the same as the polarization illumination optical system for LED light.
Note that the relationship between the vibration direction of the laser beam and the direction of the laser line beam is fixedly set. Therefore, the relationship between the vibration direction of the laser light and the transmission axis of the analyzer on the imaging lens side is adjusted, and then the polarizer on the LED illumination device side with respect to the direction of the transmission axis of the analyzer on the imaging lens side Adjust the direction of the transmission axis.

Here, an application example is demonstrated about the inspection apparatus of this invention.
The inspection apparatus of the present invention is an inspection apparatus that suppresses the occurrence of difficult-to-identify regions in either or both of a two-dimensional image and a three-dimensional image.
Difficult-to-identify areas include areas that are difficult to identify due to the transparent or semi-transparent material contained in the solder, and that may occur in places where the thickness of the solder resist on the substrate changes rapidly. It also includes any of the regions and difficult to identify regions that may occur between the metal surface for mounting the component and the solder surface.

Below, an application example is demonstrated concretely.
With reference to FIG. 5, an application example for a hard-to-recognize region caused by a transparent or translucent material contained in solder will be described.
With the polarized illumination optical system of the inspection apparatus of the present invention, it is possible to erase a difficult-to-identify area caused by a transparent material or a translucent material contained in solder such as flux. In the case of a non-polarized illumination optical system, the difficult-to-identify area is white, and the area that appears to be the same as the white part on the solder, such as white silk printing or barcode seal, is a noise component as image processing information. . A region C in FIG. 5 is a difficult-to-identify region. As a conventional method for removing the difficult-to-identify region, there is a method of changing the exposure time of the imaging camera and acquiring and interpolating an image a plurality of times. However, there is a problem that the image must be acquired a plurality of times. In the inspection apparatus of the present invention, an image having no difficult-to-identify area can be acquired by one imaging, and therefore, inspection tact time can be shortened and image processing can be simplified.

With reference to FIG. 6, an application example for a difficult-to-identify region that may occur in a place where the thickness of the solder resist provided on the substrate changes rapidly will be described.
There may be a case where a hard-to-recognize region is generated at the edge of the notched portion of the transparent material or translucent material called the solder resist, that is, the place where the thickness of the solder resist changes rapidly. The area D in FIG. 6 is a difficult-to-identify area. This difficult-to-identify area also becomes a noise component as image processing information, as in the above application example. In the polarized illumination optical system of the inspection apparatus of the present invention, the difficult-to-identify area can be erased. Thereby, it is possible to prevent a noise component from being generated as image processing information.

With reference to FIG. 7, an application example for a difficult-to-identify region that may occur between the surface of the metal for mounting the component and the surface of the solder will be described.
In the non-polarization illumination optical system of the conventional inspection apparatus, in the solder inspection of the board subjected to the solder leveler processing, there may be a case where a difficult-to-discriminate region occurs between the metal surface for mounting the component and the solder surface. . In addition, the board | substrate by which the solder leveler process was carried out is a board | substrate which performed the surface treatment which coats the solder | pewter after reflow on the surface of the copper foil part which has not applied the soldering resist on a printed circuit board.

  In the polarized illumination optical system of the inspection apparatus of the present invention, the intensity of the reflected light from the glossy silver pad portion coated with the reflowed solder is reduced, and the intensity of the reflected light is not reduced in the solder after printing. Therefore, in the inspection apparatus of the present invention, the silver pad is imaged in black and the solder is imaged in gray. As a result, a sufficient difference in image processing occurs between the brightness of the silver pad and the solder, and identification becomes possible.

Both areas A and B in FIG. 7 are solder. In the case of a conventional non-polarized illumination optical system, the reflected light from the solder and the reflected light from the silver pad are close in brightness and hue, so it is difficult to accurately identify both the monochrome image processing and the color image processing. Also, like the area B, the solder that oozes out may be completely assimilated with the silver pad.
The image obtained from the polarized illumination optical system of the inspection apparatus of the present invention is bright because the reflected light equivalent to the non-polarized illumination optical system is obtained at the solder portion and the reflected light is mostly cut off at the silver pad portion. The image recognition is easy.

  The illumination device for acquiring a two-dimensional image is not limited to the LED illumination device described above. Other illumination devices for acquiring two-dimensional images include illumination devices with laser light sources with RGB wavelengths, and white light sources that have been separated into RGB by color filters (visible light wavelengths such as three-wavelength fluorescent lamps and halogen lamps). It is possible to employ an illumination device using a light source having a RGB wavelength component.

  The illumination device for obtaining a three-dimensional image is not limited to the laser light illumination device described above. In addition, as a lighting device for acquiring a three-dimensional image, a laser displacement meter, a phase shift lighting device, or the like can be employed.

  The polarizer is not limited to the polarizing filter described above. In addition, as the polarizer, a half mirror having a reflective layer and a transmissive layer in stripes can be employed.

  The analyzer is not limited to the polarizing filter described above. In addition, as the analyzer, a half mirror having a reflective layer and a transmissive layer in stripes can be employed.

  The difficult-to-identify area may occur in the above-described difficult-to-identify area caused by the transparent or translucent material contained in the solder or in a place where the thickness of the solder resist provided on the substrate changes rapidly. It is not limited to the difficult-to-identify region or the difficult-to-identify region that may occur between the surface of the metal for mounting the component and the surface of the solder. Other difficult-to-identify areas may occur in the identification of tablets with a sugar coating that gives gloss, identification of printing on glossy capsules, or identification with the inside of an exposed tablet due to peeling of the sugar coating. There are certain difficult areas.

  The use of the inspection apparatus of the present invention is not limited to the solder printing inspection apparatus described above. Other applications of the inspection apparatus include a post-mounting board appearance inspection apparatus and a tablet inspection apparatus. Here, the tablet inspection apparatus is optimal for character recognition because it can remove a difficult-to-identify region of the tablet.

From the above, according to an embodiment for carrying out the present invention, an illumination device that irradiates light to an imaging target, an imaging device that receives reflected light from the imaging target based on the irradiation of the light, and An inspection device that is present in the imaging device and receives the reflected light, and that acquires one or both of the two-dimensional image and the three-dimensional image of the imaging target; By installing a polarizer between the imaging object and installing an analyzer between the imaging object and the imaging device, it is possible to detect a difficult-to-identify region in one or both of the two-dimensional image and the three-dimensional image. Occurrence can be suppressed.
It is to be noted that the present invention is not limited to the embodiment for carrying out the above-described invention, and various other configurations can be adopted without departing from the gist of the present invention.

Next, a mode for carrying out the second invention according to the inspection apparatus will be described.
The inspection apparatus of the present invention is an inspection apparatus in which an imaging region is provided in an imaging device, the imaging region receives reflected light, and a band-pass filter is provided on the imaging region.

Here, an application example is demonstrated about the inspection apparatus of this invention.
The inspection apparatus according to the first application example includes an imaging region group for a two-dimensional image having three imaging regions, and three bandpasses respectively corresponding to the three imaging regions on the three imaging regions. A filter is provided, and the three band-pass filters are inspection devices that transmit only red, green, and blue wavelengths, respectively.

Below, an application example is demonstrated concretely.
In Patent Document 1, a plurality of imaging regions are provided on a CMOS sensor of an imaging device. When acquiring a two-dimensional image or a three-dimensional image of a plurality of wavelengths at the same time, an imaging region having a scanning line shape as shown in FIG. 8 is provided on the CMOS sensor. In order to acquire a two-dimensional image, illumination light of different RGB is irradiated onto an imaging target, and reflected light is received in an RGB imaging region. In order to acquire a three-dimensional image, the imaging target is irradiated with laser light, and reflected light is received by the imaging area for laser.

  In order to keep the color balance during RGB composition in the illumination for scanning RGB in individual imaging areas, or to accurately grasp the reflection characteristics of each color to be irradiated, other wavelengths are used. It is necessary to prevent the illumination light from interfering with the imaging region, and there are limitations on the irradiation position and the irradiation shape.

  In order to prevent illumination light of other colors (wavelengths) from interfering with the imaging region and to reduce the irradiation blind angle, the illumination illumination method irradiates line-shaped illumination light from two front and rear directions as shown in FIG. Yes. In the case of irradiation light from two directions in a line shape, there is a problem that irradiation is not performed completely, but local irradiation blind spots occur near the joint of front and rear illumination.

  In the inspection apparatus of the present invention, as shown in FIG. 10, a plurality of wavelength band-pass filters, that is, each wavelength on the CMOS sensor is formed on a glass window that is the same as the size of the CMOS sensor or larger than the size of the CMOS sensor. A bandpass filter of a different bandpass band is coated so as to cover the imaging region of illumination, and the bandpass filter is installed as shown in FIG. 11 so as to cover each imaging region.

  As illumination for the two-dimensional image, RGB mixed light or white light was used. For RGB mixed light, LEDs having wavelengths of R (622.5 nm), G (525 nm), and B (465 nm) were used. For white light, an LED having a wavelength in the visible light range was used. Laser light (665 nm or 406 nm) was used as illumination for the three-dimensional image.

  In the illumination device for two-dimensional images of RGB mixed light or white light, a band-pass filter is installed between the imaging target. As the bandpass filter, a short pass filter (650 nm or less) was installed when laser light (665 nm) was used, and a long pass filter (430 nm or more) was installed when laser light (406 nm) was used.

  The range of wavelengths transmitted by the band-pass filter for two-dimensional images was R (622.5 nm ± 10 nm), G (525 nm ± 10 nm), and B (465 nm ± 10 nm), respectively. The wavelength range transmitted through the band-pass filter for a three-dimensional image was set to 665 nm ± 15 nm or 406 nm ± 15 nm corresponding to the laser beam (665 nm or 406 nm).

  On condition that transmission and non-transmission can be separated with a band-pass filter, the irradiation method, brightness, It is possible to capture illumination light with different conditions such as color in one scan, and it is possible to acquire image information of individual colors even if the illumination light is mixed.

  By placing a band-pass filter that transmits each imaging region on a single CMOS sensor, it is possible to solve the problem of limitation of irradiation position and irradiation shape in conventional RGB illumination.

  Since bandpass is performed immediately in front of the CMOS sensor, only the light of a necessary wavelength can be received in each imaging region, so that an irradiation method that can interfere with other imaging regions as shown in FIG. 12 is possible. In addition, it is possible to adopt an all-around irradiation method that irradiates the entire surface of the imaging field of view instead of the condensed line light with high directivity. As a result, the irradiation blind spot can be eliminated.

  The reason for using a bandpass filter instead of a color filter is that the color filter can be either R in general (G and B are not transmitted), G in general (R and B are not transmitted), B in general (G and R are transmitted) The transmission target wavelength is more than twice as wide as that of the bandpass filter. For this reason, even if each color filter is prepared for RGB, the transmission wavelength band is 50 nm or more, and the transmission regions of the respective colors overlap, so that light of an intermediate wavelength between R and G (or G and B) Will interfere. In addition, in this embodiment, in addition to the LED, a visible light laser such as red or blue-violet is used, and in order to identify them, a bandpass filter having a transmission wavelength band of 10 to 20 nm with the same color is used. Can only be done. Further, the transmittance of the target transmission wavelength can be made higher than that of the color filter.

In the inspection apparatus according to the next application example, there are a plurality of imaging region groups for two-dimensional images having three imaging regions, and three imaging regions corresponding to the three imaging regions are provided on the three imaging regions. A band-pass filter is provided, each of the three band-pass filters transmits only red, green, and blue wavelengths, and the transmission wavelength of the band-pass filter used for the plurality of imaging region groups varies between the imaging region groups. It is a different inspection device.
In addition, this inspection apparatus includes illumination apparatuses corresponding to a plurality of imaging region groups, and the individual illumination apparatuses are inspection apparatuses having different brightnesses.

Below, an application example is demonstrated concretely.
Since the reflectance of the substance is different while capturing a color image, a region that is difficult to identify may be generated, or a portion that is dark and not reflected may be generated. In order to solve these problems, for example, when the imaging sensitivity and illumination illuminance are lowered to prevent the generation of an area that is difficult to identify, the number of places that do not appear dark increases compared to before the change of the imaging sensitivity and illumination illuminance. The reverse is also true. If the imaging sensitivity is increased or the illumination illuminance is increased to brightly capture a dark part, the number of regions that are difficult to identify increases.

  As a countermeasure, there is a method of capturing an image twice or more by changing the exposure time and complementing a dark portion or a region that is difficult to identify. However, this method has a problem that it takes two or more scanning times and also requires switching between illumination illuminance and exposure time, resulting in an imaging tact.

  Therefore, in the inspection apparatus of the present invention, an illumination group 1 composed of illumination light of R1, G1, and B1 and an illumination group 2 composed of illumination light of R2, G2, and B2 that are slightly shifted in wavelength are prepared. The R1, G1, and B1 illumination devices and the R2, G2, and B2 illumination devices are each provided with a band pass filter between the imaging target. The center wavelengths of the respective bandpass filters are R1 (618 nm), G1 (522 nm), B1 (444 nm), R2 (640 nm), G2 (544 nm), and B2 (466 nm). The range of wavelengths transmitted by each bandpass filter is the center wavelength ± 10 nm.

  As shown in FIG. 13, the imaging region of the imaging device is prepared so as to correspond to the illumination group 1 of R1, G1, and B1 and the illumination group 2 of R2, G2, and B2. The range of the center wavelength of the band pass filter installed on each imaging region and the transmitted wavelength range is the same as the range of the center wavelength and the transmitted wavelength of the corresponding band pass filter on the illumination device side.

  For example, set the brightness of the illumination light of the illumination group 1 to a predetermined value, take a reference brightness image, and make the brightness of the illumination light of the illumination group 2 appear brighter or darker than the illumination group 1 Set. As a result, it is possible to acquire image data that interpolates a reference brightness image and a region that is difficult to be identified or a portion that is dark and does not appear in one scan.

  When a color filter is used instead of a bandpass filter, for example, the difference in wavelength between R1 (618 nm) and R2 (640 nm) cannot be identified, so two different types of images cannot be acquired.

FIG. 14 shows the illumination device and the experimental results.
In the lighting device of FIG. 14A, LEDs of the R1, G1, and B1 groups and LEDs of the R2, G2, and B2 groups are mounted in a ring shape. The R1 and R2, G1 and G2, and B1 and B2 LEDs of the same color are irradiated with a bandpass filter so that the wavelength is shifted by 20 nm or more. R1, G1, and B1 are irradiated with a dark illumination volume in order to prevent generation of a region in which it is difficult to identify an image. R2, G2, and B2 irradiate with brighter illumination volumes in order to capture sharp edges of lines.

  FIG. 14B shows a filter installed in front of the imaging device for R1 in the R1 imaging area, G1 in the G1 imaging area, B1 in the B1 imaging area, and R2 in the R2 imaging area. In the G2 imaging region, images are taken when bandpass filters having the same transmission wavelength band are installed for G2 and for B2 imaging region B2, and R1 and R2 are displayed as representatives.

  FIG. 14C shows a case where a filter installed in front of the image sensor is a color filter. In the case of (B), a bandpass filter is used at a wavelength difference of 20 nm between R1 and R2, and each transmission wavelength band is transmitted and the others are not transmitted. Is carved. In (C), because the color filter is used, both R1 and R2 image areas receive both R1 and R2 light, resulting in the same brightness, and a dark image and a bright image can be separated. Absent.

In the inspection apparatus according to the next application example, there are a plurality of imaging region groups for two-dimensional images having three imaging regions, and three imaging regions corresponding to the three imaging regions are provided on the three imaging regions. A band-pass filter is provided, each of the three band-pass filters transmits only red, green, and blue wavelengths, and the transmission wavelength of the band-pass filter used for the plurality of imaging region groups varies between the imaging region groups. It is a different inspection device.
Further, this inspection apparatus is an inspection apparatus in which illumination devices corresponding to a plurality of imaging region groups exist, and the light irradiated to the imaging target from each of the illumination devices has different polarization vibration directions. Here, some lighting apparatuses may not install a polarizer between the imaging target.

Below, an application example is demonstrated concretely.
Conventionally, when acquiring both a polarized image and a non-polarized image, it is necessary to switch the optical system between acquiring a polarized image and acquiring an unpolarized image. There is a problem that an imaging tact time is required due to an imaging time and operation time more than double.

  Therefore, in the inspection apparatus of the present invention, an illumination group 1 composed of illumination light of R1, G1, and B1 and an illumination group 2 composed of illumination light of R2, G2, and B2 that are slightly shifted in wavelength are prepared. The R1, G1, and B1 illumination devices and the R2, G2, and B2 illumination devices are each provided with a band pass filter between the imaging target. The center wavelengths of the respective bandpass filters are R1 (618 nm), G1 (522 nm), B1 (444 nm), R2 (640 nm), G2 (544 nm), and B2 (466 nm). The range of wavelengths transmitted by each bandpass filter is the center wavelength ± 10 nm.

  As shown in FIG. 15, the imaging region of the imaging device is prepared so as to correspond to the illumination group 1 of R1, G1, and B1 and the illumination group 2 of R2, G2, and B2. The range of the center wavelength of the band pass filter installed on each imaging region and the transmitted wavelength range is the same as the range of the center wavelength and the transmitted wavelength of the corresponding band pass filter on the illumination device side.

As shown in FIG. 16, polarizers are respectively installed between the R1, G1, and B1 illumination devices and the R2, G2, and B2 illumination devices between the imaging target. An analyzer is installed between the imaging lens and the imaging target.
Sets the transmission axis of the polarizer of the illumination device of R1, G1, B1. For example, when the polarized light emitted from the illuminating device of R1, G1, and B1 is reflected by the imaging target and the reflected polarized light reaches the analyzer, the vibration direction of the reflected polarized light is perpendicular to the transmission axis of the analyzer. Set to.
Sets the transmission axis of the polarizer of the R2, G2, B2 lighting device. For example, when the polarized light emitted from the illumination device of R2, G2, and B2 is reflected by the imaging target and the reflected polarized light reaches the analyzer, the vibration direction of the reflected polarized light is parallel to the transmission axis of the analyzer. Set to.
In some cases, the R2, G2, and B2 illumination devices are not provided with a polarizer.

According to the inspection apparatus of the present invention, as shown in FIG. 17, the image sensor can simultaneously acquire polarized image data and unpolarized image data in one scan.
A polarized image can be obtained when the polarizer is set so that the vibration direction of the reflected polarized light is perpendicular to the transmission axis of the analyzer.
An unpolarized image can be acquired when the polarizer is set so that the vibration direction of the reflected polarized light is parallel to the transmission axis of the analyzer. Further, an unpolarized image can be acquired when a polarizer is not installed in the illumination device.

Note that the inspection apparatus of the present invention is not limited to the inspection apparatus of FIG. Two sets of two illuminating devices facing each other may be provided for the imaging lens. The two lighting devices facing each other are R1, G1, and B1 lighting devices, and the remaining two lighting devices are R2, G2, and B2 lighting devices. Thereby, image data with few irradiation blind spots can be acquired.
The illumination device of the inspection apparatus of the present invention is not limited to the spot illumination device as shown in FIG. An all-around lighting device may be adopted.

  From polarized images, difficult-to-identify areas due to transparent or translucent materials contained in solder, difficult-to-identify areas that may occur in places where the thickness of the solder resist on the substrate changes rapidly, and parts It is possible to obtain an image in which the occurrence of a difficult-to-identify region or the like that may occur between the surface of the metal for mounting the solder and the surface of the solder is suppressed.

  From an unpolarized image, an image of a place that needs to be illuminated to obtain contrast with a peripheral substrate substrate such as a pad surface provided for positioning can be acquired, and positioning can be performed.

An example of the inspection apparatus of the present invention is shown in FIG. The transmission axis direction of the polarizer (not shown) of the laser light illuminating device located on the left and right of the apparatus is perpendicular to the transmission axis direction of the analyzer. The transmission axis direction of the analyzer is perpendicular to the transmission axis direction of the polarizer of the RGB illumination apparatus located below the center of the apparatus. As a result, the two-dimensional image optical system and the three-dimensional image optical system are both polarized illumination optical systems. In addition, a multi-wavelength bandpass filter is installed in front of the image sensor inside the image pickup apparatus, and light of a specific wavelength is extracted from the mixed wavelength light and picked up. The inspection apparatus of the present invention is not limited to this example.
Further, in addition to the light cutting method of FIG. 18, the same effect can be obtained in other laser displacement sensors and phase shift methods for measuring height using light.

  The range of wavelengths transmitted by the bandpass filter is preferably in the range of the center wavelength ± 10 nm. Further, it is more preferable that the transmitted wavelength range is within the range of the center wavelength ± 5 nm.

  If the wavelength range transmitted by the bandpass filter is within the range of the center wavelength ± 10 nm, there is an advantage that it is possible to pick up images by separating light and darkness, non-polarized light, etc. by shifting the wavelength even with illumination of the same color. This effect becomes more conspicuous when the transmitted wavelength range is within the range of the center wavelength ± 5 nm.

  The use of the inspection apparatus of the present invention is not limited to the solder printing inspection apparatus described above. Other applications of the inspection apparatus include a post-mounting board appearance inspection apparatus and a tablet inspection apparatus.

  From the above, according to the embodiment for carrying out the present invention, an imaging region is provided in an imaging device, the imaging region receives reflected light, and a bandpass filter is provided on the imaging region, thereby providing a novel Can be provided.

  It is to be noted that the present invention is not limited to the embodiment for carrying out the above-described invention, and various other configurations can be adopted without departing from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 1 Solder print inspection apparatus, 2 illumination apparatus, 3 imaging device, 4 control apparatus, 5 table, 10a, 10b 3D line illumination apparatus, 20a, 20b, 30a, 30b, 40a, 40b 2D line illumination apparatus, 21a 21b, 31a, 31b, 41a, 41b Two-dimensional line illumination light, 21, 31, 41 Two-dimensional line illumination light trace, 11a, 11b Three-dimensional line illumination light, 12a, 12b Three-dimensional line illumination light trace , 50 camera, 60 imaging lens, 70 image processing control unit, 71a, 71b three-dimensional imaging area image memory, 72, 73, 74 two-dimensional imaging area image memory, 80 X-axis table, 81 X-axis motor, 82 Y-axis table, 83 Y-axis motor, 100 substrate

Claims (5)

An illuminating device for irradiating the imaging object with light;
An imaging device that receives reflected light from the imaging target based on the irradiation of the light; and
An imaging element that is present in the imaging device and receives the reflected light; and
In the inspection apparatus for acquiring either or both of the two-dimensional image and the three-dimensional image of the imaging target,
An imaging region is provided in the imaging element,
The imaging area receives the reflected light,
An inspection apparatus comprising a bandpass filter on the imaging region. There are one or more imaging area groups for two-dimensional images having three imaging areas,
On the three imaging regions, three band pass filters respectively corresponding to the three imaging regions are provided,
The three bandpass filters transmit only red, green and blue wavelengths, respectively.
The inspection apparatus according to claim 1, wherein transmission wavelengths of the band-pass filters used for the plurality of imaging region groups are different between the imaging region groups. There is a lighting device corresponding to a plurality of imaging area groups,
The inspection device according to claim 2, wherein the individual illumination devices have different brightnesses. There is a lighting device corresponding to a plurality of imaging area groups,
A polarizer is installed between each of the lighting devices and the imaging target,
The inspection apparatus according to claim 2, wherein the light irradiated to the imaging target from each of the illumination devices has different polarization vibration directions. The inspection apparatus according to claim 4, wherein a part of the illumination devices does not include a polarizer between the imaging target.

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