JP2021004771A - Foreign article detection device - Google Patents

Abstract

To provide a foreign article detection device that can detect a foreign article adhered to an inspected article regardless of a surface color of the inspected article or foreign article.SOLUTION: A foreign article detection device 1 comprises: a light generation unit 10 that irradiates an inspected article and a foreign article with excitation light, and causes fluorescent light to radiate; a filter part 20 that, of the fluorescent light radiated from the inspected article and foreign article, blocks the fluorescent light in a first wavelength range, and causes the fluorescent light in a second wavelength range to transmit; a light detection unit 30 that detects the light transmitting the filter part 20; a foreign article determination unit 40 that determines presence or absence of adhesion of the foreign article to the inspected article. Let, of the wavelength range of the fluorescent light to be incident upon the filter part 20, the wavelength range in which an amount of light of the fluorescent light radiated from the foreign article is greater by an amount of reference or more in comparison with an amount of fluorescent light radiated from the inspected article be defined as a specific range, the first wavelength range has at least one part of the wavelength range except the specific range of the wavelength range of the fluorescent light to be incident upon the filter part 20 included, and the second wavelength range has at least one part of the specific range included.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a foreign matter detecting device for detecting a foreign matter adhering to an object to be inspected.

Conventionally, there is a foreign matter detection device including a camera, lighting, and an image analysis device (see, for example, Patent Document 1). This foreign matter detection device is generally easy to detect because the camera captures a transparent or translucent resin to be inspected in a state of being irradiated with blue light, and the image analysis device analyzes the captured image. Detects yellow or light brown foreign matter that is more difficult to detect than black foreign matter.

Japanese Unexamined Patent Publication No. 2001-337040

By the way, this foreign matter detection device only employs illumination that irradiates a color suitable for detecting a yellow or light brown foreign matter adhering to a transparent or translucent foreign matter, and the foreign matter or foreign matter to be inspected. Foreign matter may not be detected depending on the surface color (hereinafter referred to as the surface color). For example, when the surface colors of the object to be inspected and the foreign substance are similar, the image analyzer can detect the foreign substance because it is difficult to make a difference in contrast between the object to be inspected and the foreign substance in the image captured by the camera. difficult. That is, this foreign matter detecting device cannot detect foreign matter depending on the surface color of the object to be inspected and the surface color of the foreign matter.

An object of the present disclosure is to provide a foreign matter detecting device capable of detecting a foreign matter adhering to an inspected object regardless of the surface color of the inspected object and the foreign matter.

The invention according to claim 1
A foreign matter detection device that detects foreign matter (90) adhering to the object to be inspected (80).
A light generating unit (10) that irradiates an object to be inspected and a foreign substance with excitation light having a predetermined wavelength range to radiate fluorescence from the object to be inspected and the foreign substance in a wavelength range different from the excitation light (10). When,
A filter unit that incidents fluorescence emitted from an object to be inspected and foreign matter, blocks fluorescence in the first wavelength range, which is a predetermined wavelength range of light, and transmits fluorescence in a second wavelength range different from the first wavelength range. (20) and
A photodetector (30) that detects the light that has passed through the filter and
A foreign matter determination unit (40) for determining the presence or absence of foreign matter adhering to the object to be inspected based on the detection signal detected by the light detection unit is provided.
When the wavelength range of fluorescence incident on the filter section is defined as a wavelength range in which the amount of fluorescence emitted from a foreign substance is larger than the reference amount compared to the amount of fluorescence emitted from the object to be inspected.
The first wavelength range includes at least a part of the wavelength range of fluorescence incident on the filter unit excluding a specific range.
The second wavelength range includes at least a part of a specific range.

This makes it easier for the filter unit to transmit light having a wavelength at which the amount of fluorescence emitted from the foreign matter is larger than the amount of fluorescence emitted from the object to be inspected. Therefore, the photodetector can easily detect the fluorescence emitted from the foreign substance as compared with the fluorescence emitted from the object to be inspected. Further, the amount of fluorescence emitted from a substance when the substance is irradiated with excitation light is determined by the characteristics of the substance regardless of the surface color of the substance. Therefore, the photodetector can detect the fluorescence emitted from the foreign matter regardless of the surface color of the object to be inspected and the foreign matter.

Therefore, the foreign matter detecting device can detect the foreign matter adhering to the inspected object based on the detection signal detected by the photodetector regardless of the surface color of the inspected object and the foreign matter.

The reference numerals in parentheses attached to each component or the like indicate an example of the correspondence between the component or the like and the specific component or the like described in the embodiment described later.

It is a schematic block diagram of the foreign matter detection apparatus which concerns on embodiment. It is a perspective view of the object to be inspected which is the object of inspection of the foreign matter detection apparatus which concerns on embodiment. It is explanatory drawing for demonstrating the composition of zinc atom. It is explanatory drawing for demonstrating the composition of an atom of hydrogen. It is explanatory drawing for demonstrating the composition of the atom of sodium. It is explanatory drawing for demonstrating the excitation light and fluorescence. It is explanatory drawing for demonstrating the spectrum of fluorescence emitted from an atom. It is explanatory drawing for demonstrating the spectrum of fluorescence emitted from the substance composed of a plurality of atoms. It is a figure which shows the spectral reflectance of the object to be inspected and the foreign matter which concerns on embodiment. It is a flowchart which shows an example of the control process executed by the foreign matter determination part of the foreign matter detection apparatus which concerns on embodiment. It is a schematic diagram of the connector image of the photodetector which concerns on embodiment. It is a schematic diagram of the bush image taken by the light detection part which concerns on embodiment. It is a figure which shows an example of the bush image image of the light detection part which concerns on embodiment. It is a figure which shows an example of the bush image in the state where the filter part is not arranged in the light detection part which concerns on embodiment. It is a schematic diagram of the image obtained by binarizing the connector image taken by the photodetector according to the embodiment. It is a schematic diagram of the image obtained by binarizing the bush image of the photodetector according to the embodiment.

An embodiment of the present disclosure will be described with reference to FIGS. 1 to 16. As shown in FIG. 1, the foreign matter detection device 1 irradiates light to emit light from the object to be inspected 80, and a part of the light emitted from the object 80 to be inspected. It includes a filter unit 20 for blocking and a light detection unit 30 for detecting the light transmitted through the filter unit 20. Further, the foreign matter detection device 1 includes a foreign matter determination unit 40 that determines whether or not the foreign matter 90 adheres to the object to be inspected 80 based on the detection signal of the light detection unit 30, and light incident from the outside of the foreign matter detection device 1. It is provided with an ambient light suppression unit 50 that shields light from light, and an inspection table 60 on which an object to be inspected 80 is installed. Further, the foreign matter detection device 1 is a programmable logic controller (hereinafter, PLC) that controls the operations of the display unit 61 that displays the object to be inspected 80 and the foreign matter 90 and the foreign matter determination unit 40 based on the detection signal of the light detection unit 30. (Called) 62.

The light detection unit 30 is arranged so that the light detection surface 31 which is a surface for receiving the light of the light detection unit 30 faces downward, and the filter unit 20 is attached to the light detection surface 31. Further, in the foreign matter detecting device 1, the inspection table 60 is installed at a position facing the filter unit 20, and the light generating unit 10 is arranged between the filter unit 20 and the inspection table 60.

In the present embodiment, the object to be inspected 80 is attached to, for example, a vehicle component 70 mounted on a vehicle. A plurality of objects to be inspected 80 are attached to the vehicle component 70. As shown in FIG. 2, the vehicle component 70 is covered with a substantially cubic case 71 whose outer shell is made of polybutylene terephthalate resin (hereinafter referred to as PBT resin) which is a thermoplastic resin. When the surface of the case 71 made of PBT resin is observed with the naked eye, the surface color of the case 71 is black.

The vehicle component 70 has an electronic component arranged inside the case 71, and the insulating property is ensured by injecting an epoxy resin, which is a thermosetting resin having an insulating property, into a place where the electronic component is built. Hereinafter, the epoxy resin injection portion of the vehicle component 70 is also referred to as a resin injection portion 72. When the epoxy resin injected into the resin injection portion 72 is observed with the naked eye, the surface color of the epoxy resin is black as in the PBT resin.

Further, in the vehicle component 70, a semi-cylindrical mounting portion 73 for mounting the vehicle component 70 to the vehicle is provided on the outer wall portion of the case 71. Further, the mounting portion 73 is provided with an insertion hole for mounting the vehicle component 70 to the vehicle, and a C-ring-shaped bush 81 formed of a steel plate and having a surface galvanized is fitted in the insertion hole. ing. When the surface of the bush 81 formed of the steel plate is observed with the naked eye, the surface color of the bush 81 is silver.

Further, in the vehicle component 70, a square tubular connector 82 for passing electricity to an electronic component built in the vehicle component 70 is attached to the outer wall portion of the case 71. Inside the connector 82, a conductive portion 83 for passing electricity through electronic components is inserted.

The mounting portion 73 and the connector 82 are composed of an integrally molded product integrally molded by a molding technique such as injection molding with the case 71, and the outer wall portion is formed of the same PBT resin that forms the case 71. ing.

In the manufacturing process of the vehicle component 70, after the electronic component is installed inside the case 71, the epoxy resin is injected into the place where the electronic component is installed. When the epoxy resin adheres to a portion different from the resin injection portion 72, the vehicle This causes the component 70 to become a defective product. In other words, when the epoxy resin injected into the resin injection portion 72 adheres to the surface of the bush 81 or the outer wall portion of the connector 82, it becomes a foreign matter 90.

Hereinafter, an example in which the foreign matter detecting device 1 detects the epoxy resin adhering to the surface of the bush 81, which is the object to be inspected 80, and the outer wall portion of the connector 82 will be described.

The light generation unit 10 is a cylindrical ring illumination having holes penetrating in the vertical direction, and is configured to be capable of irradiating the object 80 to be inspected with excitation light which is light having a predetermined wavelength range. The light generating unit 10 excites the electrons e constituting the object to be inspected 80 by irradiating the object to be inspected with excitation light, and when the excited electron e returns to the ground state in which the excited electron e is stable, the excitation light is generated. The object 80 emits fluorescence, which is light having a wavelength range different from that of the above. When the foreign matter 90 is attached to the inspected object 80, the light generating unit 10 irradiates the inspected object 80 with the excitation light and also irradiates the foreign matter 90 with the excitation light, so that the foreign matter 90 is added to the inspected object 80. Fluorescence can also be generated from 90.

That is, the light generating unit 10 irradiates the inspected object 80 and the foreign matter 90 with excitation light having a predetermined wavelength range for exciting the electrons e constituting the inspected object 80 and the foreign matter 90, thereby causing the inspected object 80 and the foreign matter 90 and the foreign matter 90. Fluorescence is emitted from the foreign matter 90. The wavelength range of the fluorescence emitted from the object to be inspected 80 and the foreign matter 90 is longer than the wavelength range of the excitation light emitted by the light generating unit 10.

In the light generation unit 10, a plurality of LED illuminations 11 that irradiate excitation light are arranged over the entire circumferential direction of the inner wall portion. Each LED illumination 11 is irradiated with excitation light toward the axis of the light generating unit 10, so that the excitation light is focused in a predetermined region at a position separated from the lower surface of the light generating unit 10 by a predetermined distance. The installation angle is set in. Hereinafter, the distance between the region where the excitation light emitted by the LED illumination 11 is focused and the LED illumination 11 is also referred to as an irradiation distance.

Here, the light generating unit 10 is arranged so that the distance between the light generating unit 10 and the object to be inspected 80 is the irradiation distance. As the irradiation distance increases, the light generating unit 10 to the object to be inspected 80 are arranged. The excitation light emitted to the is dispersed. Therefore, it is desirable that the installation angle of the LED illumination 11 of the light generating unit 10 is set so that the irradiation distance becomes small. In the present embodiment, the light generating unit 10 is a low-angle type having a generally small irradiation distance, and the installation angle of the LED illumination 11 is set so that the irradiation distance is about 15 mm.

Further, in the present embodiment, the light generating unit 10 is configured to be capable of irradiating excitation light having a wavelength close to the lower limit of the wavelength range within the wavelength range of visible light. Specifically, when the wavelength intermediate between the lower limit of the visible light wavelength range and the upper limit of the visible light wavelength range is set as the visible wavelength intermediate value, the light generating unit 10 compares with the wavelength intermediate value. It is configured to be able to irradiate excitation light having a wavelength range close to the lower limit of the wavelength range of visible light. In the present embodiment, the wavelength range of visible light is a range in which the wavelength λ of light is 400 nm ≦ λ ≦ 770 nm.

The light generating unit 10 of the present embodiment is configured to be capable of irradiating excitation light having a wavelength of 405 nm, which is a wavelength close to 400 nm, which is the lower limit of the wavelength range of visible light, as compared with 585 nm, which is the intermediate value of the wavelength of visible light. Has been done.

The fluorescence emitted from the inspected object 80 and the foreign matter 90 by the excitation light emitted from the light generating portion 10 toward the lower side of the light generating portion 10 is emitted toward the upper side of the inspected object 80 and the foreign matter 90. It passes through the through hole of the light generating unit 10 and is incident on the filter unit 20. The light generating unit 10 can appropriately change the type of illumination to bar illumination or the like according to the surface color, shape, material, etc. of the object to be inspected 80 and the foreign matter 90, and the excitation light emitted by the light generating unit 10 can be used. The wavelength range of is also changeable as appropriate.

Here, the details of the excitation light irradiated to the substance and the fluorescence generated by irradiating the substance with the excitation light will be described with reference to FIGS. 3 to 8. First, a substance will be described. As shown in FIG. 3, an atom constituting a substance is formed by accommodating electrons e in a plurality of electron shells s located around the nucleus A and around the nucleus A. Holds energy around the. In the plurality of electron shells s located around the nucleus A, the K shell s1 is arranged at the position closest to the nucleus A, and the L shell s2, the M shell s3, etc. are arranged as the distance from the nucleus A increases, and each electron is arranged. A predetermined number of electrons e are housed in the shell s. For example, a zinc atom is composed of two electrons e in the K shell s1, eight electrons e in the L shell s2, and 14 electrons e in the M shell s3.

In other words, the principal quantum number indicating the type of electron shell s and the number of electrons e housed in each electron shell s are determined by atoms. For example, as shown in FIG. 4, a hydrogen atom contains one electron e in the principal quantum number (1). Further, as shown in FIG. 5, the sodium atom contains two electrons e in the principal quantum number (1) and eight electrons e in the principal quantum number (2), and the principal quantum number (2). One electron e is housed in 3).

When the electron e existing around the atom is irradiated with light having photoenergy to the electron e and absorbs the light energy, the electron e that has absorbed the light energy is compared with the nucleus before the electron e absorbs the light energy. It transitions from A to the electron shell s located far away. The transition of an electron e that has absorbed photoenergy into an electron shell s located farther from the nucleus A than before it absorbs photoenergy is called excitation of electron e, and the excited electron e is an electron after the transition. The state contained in the shell s is called the excited state of the electron e.

Since the excited state electron e becomes unstable in light energy, it tries to return to the ground state where the light energy is stable, but when returning to the ground state, fluorescence is light having a wavelength range different from that of the excited light. To generate. That is, the excitation light is light that excites the electrons e that make up a substance. Fluorescence is light emitted from a substance when an excited electron e returns to the ground state.

As shown in FIG. 6, the electron shell s in which the excited electrons e are housed differs depending on the light energy of the excitation light. The magnitude of the optical energy of the excitation light is determined by the wavelength range of the excitation light, and the larger the optical energy given to the electron e, the more the electron e can be transferred to the electron shell s farther from the atomic nucleus A. ..

Further, the wavelength range of fluorescence differs depending on the electron shell s accommodated when the excited electron e returns to the ground state. For example, the fluorescence emitted when the excited electron e returns to the K shell s1 (principal quantum number (1)) is light having a general ultraviolet light wavelength range, and is called a Lyman series. .. Further, the fluorescence emitted when the excited electron e returns to the L shell s2 (principal quantum number (2)) is light having a general visible light wavelength range, and is called a Balmer series. .. Further, the fluorescence emitted when the excited electron e returns to the M shell s3 (principal quantum number (3)) is light having a wavelength range of general infrared light, and is called the Paschen series. is there.

When the wavelength range of the excitation light is constant, the wavelength range of fluorescence generated by irradiation with the excitation light and the amount of light energy for each wavelength are fixed for each atom. For example, FIG. 7 shows the amount of light energy for each wavelength of fluorescence generated when a predetermined atom is irradiated with excitation light by a solid line, and when an atom whose broken line is different from the predetermined atom is irradiated with excitation light. The amount of light energy for each wavelength of fluorescence generated in is shown. Hereinafter, what shows the light energy for each wavelength of fluorescence is also referred to as a fluorescence spectrum.

As shown in FIG. 7, in the fluorescence spectrum, in the wavelength range in which the fluorescence wavelength has light energy, the light energy increases as the fluorescence wavelength increases from the shortest wavelength to the longer wavelength. Further, in the fluorescence spectrum, when the wavelength of fluorescence is longer than the wavelength at which the light energy is maximized, the light energy becomes smaller as the wavelength becomes longer. That is, the fluorescence spectrum has a mountain-shaped shape in which the light energy in the central portion of the wavelength range is high and the light energy on both sides of the wavelength range is low as compared with the central portion. In the fluorescence spectrum, the wavelength range and the light energy for each wavelength are different for each atom.

Further, the spectrum of fluorescence generated from a substance composed of a plurality of atoms is a spectrum synthesized by the spectrum of fluorescence generated from each atom constituting the substance. Therefore, as shown in FIG. 8, the spectrum of fluorescence generated from a substance composed of a plurality of atoms is the sum of the optical energies of each wavelength of the spectrum of fluorescence generated from each atom constituting the substance. Become. The light energy of each wavelength in the fluorescence spectrum increases or decreases depending on the light energy of the excitation light.

Subsequently, the filter unit 20 will be described. The filter unit 20 incidents fluorescence emitted from the object to be inspected 80 and the foreign matter 90, blocks the fluorescence in a predetermined wavelength range among the incident fluorescence, and has a predetermined wavelength. It is an optical filter that transmits fluorescence outside the range. That is, the filter unit 20 blocks fluorescence in the first wavelength range, which is a predetermined wavelength range of light, and transmits fluorescence in a second wavelength range different from the first wavelength range.

Here, among the wavelength ranges of the fluorescence incident on the filter unit 20, the wavelength range in which the amount of fluorescence emitted from the foreign matter 90 is larger than the reference amount is specified as compared with the amount of fluorescence emitted from the object 80 to be inspected. The range. The first wavelength range is a range that includes at least a part of the wavelength range of the fluorescence incident on the filter unit 20 excluding the specific range. The second wavelength range is a range that includes at least a part of the specific range. The amount of light is the total amount of light energy radiated per unit time.

The reference amount is a reference amount of light when calculating a specific range, and is a wavelength range of a specific range determined by the difference between the amount of fluorescence emitted from the foreign matter 90 and the amount of fluorescence emitted from the object 80 to be inspected. It is determined by a value of 0 or more to determine. The larger the reference amount is, the smaller the range is, and the smaller the reference amount is, the larger the range is. When the reference amount is 0, the specific range is the maximum.

Here, the amount of excitation light and the amount of fluorescence light will be described. When fluorescence is emitted from a substance by irradiating the substance with excitation light having a predetermined amount of light, the amount of fluorescence light is compared with the amount of excitation light. And less. Further, the ratio of the amount of fluorescence light to the amount of excitation light for each wavelength of fluorescence is determined by the characteristics of the substance. Hereinafter, the ratio of the amount of fluorescence light to the amount of excitation light is also referred to as spectral reflectance.

Here, the spectral reflectances of the object to be inspected 80 and the foreign matter 90 will be described with reference to the graph shown in FIG. The line shown in FIG. 9 shows the spectral reflectance of the outer wall portion of the connector 82, which is the object 80 to be inspected made of PBT resin, and the alternate long and short dash line is the bush 81, which is the object 80 to be inspected made of steel plate. The spectral reflectance of the surface is shown, and the spectral reflectance of the epoxy resin in which the alternate long and short dash line is the foreign matter 90 is shown. The outer wall portion of the case 71 and the outer wall portion of the mounting portion 73 are made of the same PBT resin as the outer wall portion of the connector 82. Therefore, the spectral reflectance of the outer wall portion of the case 71 and the outer wall portion of the mounting portion 73 is the same as the spectral reflectance of the outer wall portion of the connector 82.

The graph of the spectral reflectance shown in FIG. 9 shows the result of measuring the spectral reflectance in the wavelength range of 360 nm to 740 nm by the SCI method (Specular Component Exclude method) using the spectrocolorimeter CM-2600D manufactured by Konica Minolta. It shows.

As shown in FIG. 9, the spectral reflectance of the connector 82 is 10% or less within the measurement range. Further, the spectral reflectance of the bush 81 is 40% or more and 60% or less within the measurement range, and has a mountain-shaped shape in which the wavelength of fluorescence is about 60% of the maximum value at about 500 nm.

It is known that the spectral reflectance of the connector 82 and the spectral reflectance of the bush 81 decrease as the wavelength becomes longer in a wavelength range longer than 740 nm, which is outside the measurement range.

Further, the spectral reflectance of the epoxy resin is approximately 5% within the measurement range in the wavelength range of about 700 nm or less, and the wavelength range becomes longer in the wavelength range longer than about 700 nm. As a result, it grows rapidly. The spectral reflectance of the epoxy resin is larger than the spectral reflectance of the bush 81 when the wavelength of fluorescence outside the measurement range is about 780 nm, and becomes about 90%, which is the maximum value at about 800 nm. I know.

Comparing the connector 82 and the epoxy resin, the spectral reflectance of the epoxy resin is larger than the spectral reflectance of the connector 82 in the wavelength range where the fluorescence wavelength is about 720 nm or more. Therefore, when the amount of excitation light applied to the connector 82 and the epoxy resin is the same, the amount of fluorescence emitted from the epoxy resin is the fluorescence emitted from the connector 82 in the wavelength range of about 720 nm or more. It becomes larger than the amount of light of.

Further, when the bush 81 and the epoxy resin are compared, the spectral reflectance of the epoxy resin is larger than the spectral reflectance of the bush 81 in the wavelength range where the fluorescence wavelength is about 780 nm or more. Therefore, when the amount of excitation light applied to the bush 81 and the epoxy resin is the same, the amount of fluorescence emitted from the epoxy resin is the fluorescence emitted from the bush 81 in the wavelength range of about 780 nm or more. It becomes larger than the amount of light of.

Therefore, in the present embodiment, the amount of fluorescence emitted from the epoxy resin is emitted from either the connector 82 or the bush 81 in the wavelength range of about 780 nm or more in the wavelength range of the fluorescence incident on the filter unit 20. It is also large compared to the amount of fluorescent light. That is, the specific range determined by the difference between the amount of fluorescence light emitted from the foreign matter 90 and the amount of fluorescence light emitted from the object 80 to be inspected is approximately 780 nm or more when the reference amount at which the specific range is maximized is 0. It is in the wavelength range. In this case, the first wavelength range is a range that includes at least a part of the wavelength range shorter than about 780 nm. The second wavelength range is a range that includes at least a part of a wavelength range longer than about 780 nm.

Therefore, the filter unit 20 blocks the fluorescence in the wavelength range including at least a part of the wavelength range shorter than about 780 nm, and transmits the fluorescence in the wavelength range including at least a part of the wavelength range longer than about 780 nm. .. Specifically, in the present embodiment, the filter unit 20 employs a sharp cut filter that blocks light having a wavelength of 640 nm or less, which is a wavelength range shorter than 780 nm, and transmits light having a wavelength longer than 640 nm.

The filter unit 20 is attached to the photodetector unit 30 so as to cover the front surface of the photodetector surface 31, and detects light having a wavelength longer than 640 nm among the fluorescence emitted from the object to be inspected 80 and the foreign matter 90. It is incident on 30. The filter unit 20 can appropriately change the type of filter such as a low-pass filter or band-pass filter according to the characteristics, shape, etc. of the object to be inspected 80 and the foreign matter 90, and can also appropriately change the wavelength range to be blocked. is there.

The photodetector 30 is a light receiving device that detects the light transmitted through the filter unit 20, and is configured to be capable of detecting the wavelength range of visible light and the wavelength range of near infrared light. In the present embodiment, the wavelength range of near-infrared light is a range in which the wavelength λ of light is 770 nm <λ ≦ 25000 nm. Therefore, the photodetection unit 30 detects the light having a wavelength λ of 400 nm ≦ λ ≦ 25,000 nm among the light transmitted through the filter unit 20.

Further, the photodetector 30 is a CCD (Charged-coupled) having an image pickup device (not shown) that converts the received light into an electric signal and outputs the light, and an image pickup unit (not shown) that images the subject based on the electric signal output by the image pickup device. devices) Consists of a camera. The photodetector 30 is configured to be able to image the object to be inspected 80 and the foreign matter 90 based on the amount of light transmitted through the filter unit 20 and incident on the photodetector 30.

In the photodetector 30, the image sensor has 400,000 light receiving elements built-in, and when each light receiving element receives light in the detectable wavelength range, the brightness indicates the amount of light according to the amount of received light. It is converted into an electric signal having value information and output to the image sensor.

In the present embodiment, for example, an 8-bit monochrome camera is adopted as the photodetector 30, and the luminance value of 256 gradations from 0 to 255 by the image sensor depends on the amount of light received by the light receiving element. It is converted into an electric signal having the above information and output to the image sensor. The photodetector 30 outputs an electric signal having information that the brightness value is 255 when the image sensor receives the largest amount of light, and the photodetector 30 detects the light. If it cannot be done, an electric signal having information that the brightness value is 0 is output to the image sensor. That is, the information on the brightness value of the electric signal increases as the amount of light received by the light receiving element increases, and decreases as the amount of light received by the light receiving element decreases.

Further, the photodetector 30 sets the region received by one light receiving element as one pixel, and sets the luminance value of 256 gradations to 256 gradations of light and shade based on the electric signal received from the image pickup element by the image pickup unit. The converted light and shade image can be output as a captured image of 400,000 pixels. For example, when the photodetecting unit 30 receives an electric signal having brightness value information of 255 from the light receiving element, the light detecting unit 30 obtains color information displayed by pixels in the region of the light receiving element in 256 gradations of shades. Of these, it is output as white, which is the brightest color. Further, when the photodetecting unit 30 receives an electric signal having the information of the luminance value of 0 from the light receiving element, the light detecting unit 30 obtains the color information displayed by the pixels in the region of the light receiving element in 256 gradations. Of these, the darkest color, black, is output. In this way, the photodetector 30 outputs each pixel in the imaging range in one of 256 gradations of light and shade according to the amount of light received by each light receiving element, whereby the object to be inspected 80 And the foreign body 90 is imaged.

The light detection unit 30 is connected to the foreign matter determination unit 40, and is configured to be able to output the captured grayscale image to the foreign matter determination unit 40. The photodetector 30 may be composed of a camera or the like whose image element is a CMOS (Complementary metal-oxide-semiconductor).

The foreign matter determination unit 40 is an image processing device that determines whether or not the foreign matter 90 adheres to the object to be inspected 80 based on the grayscale image received from the light detection unit 30. The foreign matter determination unit 40 is mainly composed of a microcomputer, and preset control programs and updatable control programs are stored in various memories (ROM, RAM, EEPROM, etc.) built in as storage means.

The foreign matter determination unit 40 performs binarization processing on the shading image received from the light detection unit 30, and extracts pixels indicating the foreign matter 90 from the image after the binarization processing to extract foreign matter indicating the foreign matter 90 from the image to be inspected. It is configured so that the presence or absence of adhesion of 90 can be determined.

Specifically, the foreign matter determination unit 40 compares the luminance value of each pixel with a predetermined luminance value for each pixel constituting the grayscale image, and changes the color of the pixel whose luminance value is equal to or greater than the predetermined luminance value to white. The conversion is performed, and the color of the pixel whose luminance value is less than a predetermined luminance value is converted to black. Then, the foreign matter determination unit 40 converts the shading image received from the light detection unit 30 into a black-and-white image in which the color of each pixel is displayed in either white or black, and extracts the foreign matter 90 from the black-and-white image. To do.

The predetermined luminance value is a threshold value for binarizing the grayscale image. The predetermined luminance value is determined by, for example, creating a histogram by calculating the number of pixels for each gradation of the luminance value in the shade image, and defining the pixels to be extracted from the created histogram with a value that can be distinguished from other pixels. Be done. In the present embodiment, the predetermined luminance value indicates the color of the pixel indicating the foreign matter 90 to be white and the object to be inspected 80 by performing binarization processing on the shade image showing the foreign matter 80 and the foreign matter 90. The color of the pixel is defined as black by a distinguishable value.

Further, the foreign matter determination unit 40 selects a predetermined range as the inspection range R from the entire range of the image displayed as a black-and-white image, and in the image indicated by the selected inspection range R, the foreign matter with respect to the object to be inspected 80. It is configured so that the presence or absence of adhesion of 90 can be determined. Therefore, the foreign matter determination unit 40 is configured to be able to extract the pixel indicating the foreign matter 90 from the pixels constituting the image of the inspection range R from the entire range of the black-and-white image showing the foreign matter 80 and the foreign matter 90. ing.

The inspection range R is a range of an image composed of pixels selected in advance by the foreign matter determination unit 40 as an inspection target, and is surrounded by a quadrangle such as a rectangle or a square in the imaging range imaged by the light detection unit 30. It is selected in the range. In the present embodiment, the inspection range R is selected so that the image of the object to be inspected 80 is arranged in the inspection range R in the imaging range imaged by the photodetector 30.

The foreign matter determination unit 40 is connected to the display unit 61, and is configured to be able to output the shade image received from the light detection unit 30 to the display unit 61.

Further, the foreign matter determination unit 40 is connected to the PLC 62, and the operation of the foreign matter determination unit 40 can be controlled based on the signal transmitted from the PLC 62. Further, the PLC 62 is connected to the inspection table 60, and the position of the inspection table 60 can be adjusted based on the signal output from the PLC 62.

The disturbance light suppression unit 50 is a light-shielding cover for suppressing the incident of disturbance light, which is light other than fluorescence emitted from the object to be inspected 80 and the foreign matter 90, on the light detection unit 30. In the present embodiment, the disturbance light suppressing portion 50 is formed of a light-shielding polycarbonate in a square tubular bottomed shape, and is arranged on a support portion 51 for attaching the disturbance light suppressing portion 50. The ambient light suppression unit 50 houses a light generation unit 10, a filter unit 20, and a light detection unit 30 inside, and an object to be inspected 80 is arranged below the opening portion of the disturbance light suppression unit 50. To.

The ambient light suppression unit 50 may be made of a resin member other than polycarbonate or a metal member such as stainless steel or aluminum as long as it has a light-shielding property. Further, the ambient light suppression unit 50 may be configured to accommodate the object to be inspected 80 inside, and in this case, a lid for closing the opening portion may be provided.

Subsequently, the operation of the foreign matter detection device 1 will be described with reference to the flowchart shown in FIG. The foreign matter detection device 1 waits until the object to be inspected 80 is placed at a predetermined inspection position, and starts the foreign matter detection process when the object to be inspected 80 is placed at a predetermined inspection position. Further, the foreign matter detection device 1 ends the foreign matter detection process when the determination of the adhesion of the foreign matter 90 to the inspected object 80 is completed and the inspected object 80 is discharged from the predetermined inspection position.

The connector 82 and the bush 81, which are the objects to be inspected 80 of the present embodiment, are incorporated in one vehicle component 70, and predetermined inspection positions are defined for each. Therefore, when inspecting the connector 82 and the bush 81, the PLC 62 adjusts the position of the inspection table 60 so that either the connector 82 or the bush 81 is within the imaging range of the photodetector 30.

The foreign matter determination unit 40 first determines in step S10 whether or not the image capture instruction signal is input from the PLC 62. The image capture signal is an input signal transmitted from the PLC 62 to the foreign matter determination unit 40 when the object to be inspected 80 is arranged at a predetermined inspection position, and is a start signal of the foreign matter detection process.

If it is determined as a result of the determination process in step S10 that the image capture signal has not been input from the PLC 62, the foreign matter determination unit 40 does not start the foreign matter detection process and waits until the image capture signal is input. Maintain the state. On the other hand, when it is determined that the image capture signal has been input as a result of the determination process in step S10, the foreign matter determination unit 40 captures the light and shade image captured by the light detection unit 30 in step S11.

After capturing the light and shade image captured by the light detection unit 30, the foreign matter determination unit 40 outputs a capture completion signal to the PLC 62 in step S12, notifies the PLC 62 that the light and shade image has been captured, and captures the image. The shading image is output to the display unit 61. The display unit 61 that has received the shade image displays the received shade image.

Here, the light and shade images obtained by the photodetector 30 capturing the object to be inspected 80 and the foreign matter 90 will be described with reference to FIGS. 11 to 14. FIG. 11 is a schematic view of an image obtained by the photodetector 30 capturing the connector 82. Further, FIG. 12 is a schematic view of an image obtained by the photodetector 30 capturing the bush 81.

Further, FIG. 13 is an example of an actual image obtained by the photodetector 30 capturing the bush 81. Further, FIG. 14 is an example of an actual image in which the light detection unit 30 captures the bush 81 in a state where the filter unit 20 is not attached to the light detection surface 31 of the light detection unit 30.

For convenience of explanation of the figure, in the schematic diagram of the image, the shading of the pixels is displayed with the hatching of the dot pattern. The hatched dot pattern displays dark colors with dense dots compared to bright colors, and attaches them so that the density of the dots increases as the pixel density increases from white to black. To do.

As described above, the spectral reflectance of the connector 82 is 10% or less in the wavelength range that can be detected by the photodetector 30. That is, the amount of fluorescence emitted from the connector 82 in the wavelength range that can be detected by the photodetector 30 is significantly smaller than the amount of excitation light. Therefore, even if the connector 82 is irradiated with the excitation light, the connector 82 hardly emits fluorescence, so that the light detection unit 30 can hardly receive the fluorescence emitted from the connector 82. In this case, as shown in FIG. 11, the photodetector 30 captures the pixel on which the connector 82 is imaged in a color similar to black.

Further, as described above, the spectral reflectance of the epoxy resin is about 5% in the wavelength range shorter than about 700 nm, but suddenly increases in the wavelength range of 700 nm or more, and the maximum wavelength is about 800 nm. It will be about 90% of the value. Therefore, the amount of fluorescence emitted by the epoxy resin in the wavelength range that can be detected by the photodetector 30 is significantly larger than the amount of fluorescence emitted from the connector 82.

Further, in the present embodiment, the filter unit 20 blocks light having a wavelength of 640 nm or less, which is light including a fluorescence wavelength radiated from the connector 82 within the first wavelength range. Further, the filter unit 20 transmits light having a wavelength longer than 640 nm, which is within the second wavelength range and includes a wavelength at which the spectral reflectance of fluorescence emitted from the epoxy resin is maximized.

Further, since the light detection unit 30 in the present embodiment can detect light in the wavelength range of near infrared light in addition to light in the wavelength range of visible light, the spectral reflectance of the epoxy resin is maximized at about 800 nm. Wavelength fluorescence can be detected. Therefore, as shown in FIG. 11, the light detection unit 30 uses pixels that image the epoxy resin injected into the resin injection unit 72 and the epoxy resin that is the foreign matter 90 adhering to the connector 82 as the pixels that image the connector 82. It is possible to image in a relatively bright color.

If the light detection unit 30 detects light in the visible light wavelength range as in the prior art, the light detection unit 30 has a spectral reflectance of 10% or less in the visible light wavelength range. , The fluorescence emitted from the connector 82 can hardly be received. Further, since the spectral reflectance of the epoxy resin in the wavelength range of visible light is about 5% in most of the wavelength range of visible light, the light detection unit 30 can hardly receive the fluorescence emitted from the epoxy resin. ..

Therefore, the photodetector 30 captures the pixels obtained by imaging the connector 82 and the epoxy resin which is the foreign matter 90 adhering to the connector 82 in a color similar to black. Therefore, even if the epoxy resin, which is a foreign substance 90, adheres to the connector 82, it is difficult to make a difference in contrast between the pixel in which the connector 82 is imaged and the pixel in which the epoxy resin is imaged.

Further, with reference to FIG. 12, as described above, the spectral reflectance of the bush 81 reaches a maximum value when the wavelength of fluorescence is approximately 500 nm, and the value is about 60%. Therefore, the bush 81 emits fluorescence having a larger amount of light than the fluorescence emitted by the connector 82.

However, in the present embodiment, the filter unit 20 blocks light having a wavelength of 640 nm or less, which is within the range of the first wavelength range. That is, the filter unit 20 blocks light having a wavelength that maximizes the spectral reflectance of fluorescence emitted from the bush 81. Therefore, as shown in FIG. 12, the light detection unit 30 converts the pixels obtained by imaging the epoxy resin injected into the resin injection unit 72 and the epoxy resin which is the foreign matter 90 adhering to the bush 81 into the pixels obtained by imaging the bush 81. It is possible to image in a relatively bright color.

If the filter unit 20 is not arranged on the light detection surface 31 of the light detection unit 30, the light detection unit 30 has a wavelength range including a wavelength at which the spectral reflectance of fluorescence emitted from the bush 81 is maximized. Detect light. In this case, the photodetector 30 detects a larger amount of fluorescent light radiated from the bush 81 than when the filter unit 20 is arranged on the photodetection surface 31. Therefore, the photodetector 30 captures the pixel in which the bush 81 is imaged in a color similar to the pixel in which the epoxy resin is imaged.

13 and 14 are examples of images taken by the photodetector 30 of the bush 81 and the epoxy resin adhering to the bush 81. The image of FIG. 14 is an example of an image of the bush 81 and the epoxy resin adhering to the bush 81 in a state where the filter unit 20 is not arranged on the light detection surface 31 of the light detection unit 30.

In the image of FIG. 13, the portion displayed in white is the portion of the pixel in which the epoxy resin adhering to the surface of the bush 81 is imaged. As shown in FIG. 13, the photodetector 30 can image the pixels in which the epoxy resin attached to the bush 81 is imaged in a brighter color than the pixels in which the bush 81 is imaged. On the other hand, as shown in FIG. 14, when the filter unit 20 is not arranged on the light detection surface 31 of the light detection unit 30, the photodetection unit 30 images the bush 81 and the epoxy resin in similar colors.

Subsequently, in step S13, the foreign matter determination unit 40 performs a binarization process on the shading image received from the light detection unit 30. The foreign matter determination unit 40 converts the pixels showing the epoxy resin, which is the foreign matter 90, into white, and the other pixels into black in the grayscale image in which the foreign matter 80 and the foreign matter 90 are captured.

Specifically, an image of the connector 82 is shown in FIG. As shown in FIG. 15, the foreign matter determination unit 40 converts the pixels constituting the epoxy resin injected into the resin injection unit 72 and the epoxy resin adhering to the connector 82 into white within the imaging range, and converts the other pixels into white. Convert to black. An image of the bush 81 is shown in FIG. As shown in FIG. 16, the foreign matter determination unit 40 converts the pixels obtained by imaging the epoxy resin and the epoxy resin adhering to the bush 81 to white, and the other pixels to black.

Subsequently, in step S14, the foreign matter determination unit 40 extracts the pixels displayed in white from the entire range of the converted black-and-white image, and in step S15, measures the number of the extracted white pixels. Then, the operation of the light generating unit 10 is confirmed.

If the light generating unit 10 does not irradiate the excitation light, the photodetecting unit 30 cannot detect the fluorescence emitted from the object to be inspected 80 and the foreign matter 90, so that the entire imaging range is displayed in black. Is output to the foreign matter determination unit 40. Then, since the foreign matter determination unit 40 cannot extract the pixel indicating the epoxy resin which is the foreign matter 90 from the imaging range, even if the foreign matter 90 is attached to the object to be inspected 80, it is erroneously determined that the foreign matter 90 is not attached. There is a risk of Therefore, it is desirable that the foreign matter determination unit 40 confirms that the excitation light is emitted from the light generation unit 10 before determining whether or not the foreign matter 90 adheres to the object to be inspected 80.

In the present embodiment, the position of the inspection table 60 is such that when the object to be inspected 80 is placed at a predetermined inspection position, a part of the resin injection unit 72 in addition to the object to be inspected 80 is in the imaging range of the photodetection unit 30. Arranged to be included in. Specifically, when the foreign matter detection device 1 inspects the presence or absence of foreign matter 90 adhering to the connector 82, the position of the inspection table 60 is such that a part of the connector 82 and the resin injection unit 72 is within the imaging range of the light detection unit 30. Arranged to be included. Further, when the foreign matter detecting device 1 inspects the presence or absence of the foreign matter 90 adhering to the bush 81, the inspection table 60 includes a part of the bush 81 and the resin injection portion 72 of the epoxy resin in the imaging range of the light detecting portion 30. Arranged like this.

Therefore, the light detection unit 30 is injected into the resin injection unit 72 at least when the light generation unit 10 is irradiating the excitation light, even if the epoxy resin is not attached to the object to be inspected 80. The image obtained by capturing the image of the epoxy resin can be output to the foreign matter determination unit 40. Therefore, the foreign matter determination unit 40 confirms the operation of the light generation unit 10 by extracting the pixels obtained by imaging the epoxy resin injected into the resin injection unit 72 based on the image received from the light detection unit 30. Can be done.

Specifically, in step S15, the foreign matter determination unit 40 measures the number of white pixels that image the epoxy resin extracted in step S14, and the number of pixels that image the epoxy resin is equal to or greater than the number of illumination determinations. Judge whether or not.

As a result of the determination process in step S15, when the number of pixels in which the epoxy resin is imaged is less than the number of illumination determinations, the foreign matter determination unit 40 determines that the light generation unit 10 is malfunctioning, and in step S16, a signal of inspection failure. Is output to the PLC62. On the other hand, as a result of the determination process in step S15, when the number of pixels in which the epoxy resin is imaged is equal to or greater than the number of illumination determinations, the foreign matter determination unit 40 determines that the operation of the light generation unit 10 is normal.

Here, the number of illumination determinations is a value predetermined in the foreign matter determination unit 40 in advance, and is the pixel of the resin injection unit 72 imaged by the light detection unit 30 when the object to be inspected 80 is arranged at a predetermined inspection position. Set based on the number. For example, the number of illumination determinations is set by the minimum number of pixels that image the predicted resin injection unit 72 within the imaging range imaged by the photodetector unit 30. The number of illumination determinations can be changed to an arbitrary value depending on the inspection position of the object to be inspected 80, the imaging range of the light detection unit 30, and the like.

Subsequently, in step S17, the foreign matter determination unit 40 extracts white pixels indicating the epoxy resin from the black-and-white image converted in step S13. Here, when the foreign matter determination unit 40 extracts the epoxy resin in the entire range of the black and white image, not only the epoxy resin which is the foreign matter 90 but also the epoxy resin injected into the resin injection unit 72 is extracted, so that the foreign matter determination unit 40 extracts the epoxy resin. , Only the foreign matter 90 cannot be detected. Therefore, the foreign matter determination unit 40 extracts only the pixels showing the epoxy resin from the image of the inspection range R excluding the portion imaged by the resin injection unit 72 from the range of the image captured by the light detection unit 30. ..

In the present embodiment, in the inspection range R, when the object to be inspected 80 is placed at a predetermined inspection position, an image of the object to be inspected 80 is included in the inspection range R, and the resin injection unit 72 is imaged. The image is set so as not to be included in the inspection range R.

For example, when inspecting the connector 82, as shown in FIG. 15, the inspection range R includes an image of the connector 82 and does not include an image of the resin injection portion 72. It is a range, and is set in a wide range as compared with the imaging portion of the connector 82. Further, when inspecting the bush 81, as shown in FIG. 16, the inspection range R includes an image of the bush 81 imaged and does not include an image of the resin injection portion 72 imaged in the inspection range R. It is a range, and is set in a wide range as compared with the imaging portion of the bush 81.

Subsequently, in step S18, the foreign matter determination unit 40 measures the number of pixels indicating the epoxy resin extracted from the inspection range R to determine whether or not the foreign matter 90 is attached to the object to be inspected 80. Specifically, the foreign matter determination unit 40 determines whether or not the number of pixels in which the extracted epoxy resin is imaged is equal to or greater than the number of foreign matter determination.

Here, the foreign matter determination number is a value predetermined in the foreign matter determination unit 40 in advance, and is an upper limit value of an allowable range in which the inspected object 80 is allowed as a normal product when the foreign matter 90 adheres to the inspected object 80. Set in. That is, the foreign matter determination number is set as a reference value for determining whether the inspected object 80 is a normal product or a defective product when the foreign matter 90 adheres to the inspected object 80. The number of foreign objects determined may be set to a different value depending on the object to be inspected 80.

As a result of the determination process in step S18, when the number of pixels indicating the epoxy resin in the image of the inspection range R is larger than the number of foreign matter determination, the foreign matter determination unit 40 determines that the foreign matter 90 is attached to the object 80 to be inspected. , In step S16, the inspection failure signal is output to the PLC 62. On the other hand, as a result of the determination process in step S18, when the number of pixels indicating the epoxy resin in the image of the inspection range R is equal to or less than the number of foreign matter determination, the foreign matter determination unit 40 determines that the foreign matter 90 does not adhere to the inspected object 80. , In step S19, a signal of normal inspection completion is output to the PLC 62.

Upon receiving the inspection failure signal or the inspection normal completion signal, the PLC 62 moves the inspection table 60 and discharges the inspection object 80 from the predetermined inspection position.

According to the foreign matter detection device 1 of the present embodiment described above, the filter unit 20 emits light having a wavelength at which the amount of fluorescence emitted from the foreign matter 90 is larger than the amount of fluorescence emitted from the object 80 to be inspected. Is easy to see through. Therefore, the photodetector 30 can easily detect the fluorescence emitted from the foreign matter 90 as compared with the fluorescence emitted from the object 80 to be inspected.

Here, the amount of fluorescence emitted from a substance by irradiating the substance with excitation light is determined by the characteristics of the substance regardless of the surface color of the substance when the amount of excitation light is constant. Therefore, the photodetector 30 can detect the fluorescence emitted from the foreign matter 90 regardless of the surface colors of the foreign matter 80 and the foreign matter 90.

Therefore, the foreign matter detecting device 1 can detect the foreign matter 90 adhering to the inspected object 80 based on the detection signal detected by the light detection unit 30 regardless of the surface colors of the inspected object 80 and the foreign matter 90. ..

Further, when the light generating unit 10 irradiates light in a wavelength range outside the visible light wavelength range (for example, infrared light), the user cannot confirm the excitation light with the naked eye, and thus the light generating unit 10 It is not possible to confirm the operation of whether or not is irradiating the excitation light. Further, when the light generating unit 10 irradiates light in a wavelength range shorter than the wavelength range of general visible light (for example, ultraviolet light), in addition to being unable to confirm the excitation light with the naked eye, the foreign matter detecting device 1 may be used. It is necessary to take measures to prevent the user from being irradiated with the excitation light.

On the other hand, since the foreign matter detecting device 1 employs a light generating unit 10 that irradiates excitation light in the wavelength range of visible light, the user can visually confirm the light emitted from the light generating unit 10. .. Further, the foreign matter detection device 1 does not require any measures for suppressing the user from being irradiated with the excitation light.

By the way, in the fluorescence emitted from a substance by irradiating the substance with excitation light, the larger the optical energy of the excitation light, the greater the fluorescence optical energy. Therefore, the light energy of fluorescence emitted from the object to be inspected 80 and the foreign matter 90 increases as the light energy of the excitation light emitted by the light generating unit 10 increases. The amount of fluorescence emitted from the inspected object 80 and the foreign matter 90 increases as the light energy of the excitation light radiated from the inspected object 80 and the foreign matter 90 increases.

The foreign matter detection device 1 can stably detect the fluorescence radiated from the foreign matter 90 as the amount of fluorescence emitted from the foreign matter 90 increases, so that the excitation light having a larger light energy can be detected. It is desirable to employ a light generating unit 10 capable of irradiating. The optical energy E possessed by the excitation light is defined based on Planck's constant h, the light velocity c, and the wavelength λ of the light by the following mathematical formula, and the shorter the wavelength of the excitation light, the larger the optical energy.
E = h × c / λ

On the other hand, the foreign matter detection device 1 can irradiate the excitation light of 405 nm, which is a wavelength closer to the lower limit of the visible light wavelength range than the intermediate wavelength value, in the visible light wavelength range 10. Has been adopted. Therefore, the fluorescent light energy radiated from the foreign matter 90 becomes larger than the fluorescent light energy radiated from the foreign matter 90 when the light generating unit 10 irradiates the excitation light having a wavelength longer than the intermediate wavelength value. , The light detection unit 30 can stably detect the fluorescence emitted from the foreign matter 90. Therefore, the foreign matter detecting device 1 adheres to the object to be inspected 80 as compared with the case where the light generating unit 10 detects the fluorescence emitted from the foreign matter 90 by irradiating the excitation light having a wavelength longer than the intermediate wavelength value. Foreign matter 90 can be detected stably.

Further, the foreign matter detection device 1 can determine that the foreign matter 90 is attached when the number of pixels indicating the foreign matter 90 among the pixels constituting the image is equal to or greater than the number of foreign matter determination. Therefore, for example, even if the foreign matter 90 is attached to the foreign matter 80, the foreign matter detecting device 1 normally determines the foreign matter 80 when the number of pixels indicating the foreign matter 90 is within the permissible range. Based on the number of pixels of 90, it is possible to determine the adhesion of the foreign matter 90 to the object to be inspected 80.

Further, since the foreign matter detecting device 1 can determine the presence or absence of the foreign matter 90 adhering to the inspected object 80 based on the number of pixels indicating the foreign matter 90, the foreign matter 90 is quantitatively attached to the inspected object 80. It is possible to determine the presence or absence of adhesion.

By the way, when the disturbance light which is the light of the sun or illumination includes the wavelength range of fluorescence emitted from the foreign matter 90, when the disturbance light is incident on the light detection surface 31 of the light detection unit 30, the foreign matter determination unit 40 causes the foreign matter determination unit 40 to enter. There is a possibility that the detection signal of the ambient light is determined as the fluorescence emitted from the foreign matter 90.

On the other hand, since the foreign matter detecting device 1 includes the disturbance light suppressing unit 50, it is possible to suppress the incident of the disturbance light on the light detection surface 31 of the light detection unit 30. Therefore, the foreign matter detecting device 1 can prevent the foreign matter determining unit 40 from erroneously determining the adhesion of the foreign matter 90 to the object to be inspected 80, as compared with the case where the foreign matter detecting unit 50 is not provided. ..

(Other embodiments)
Although the typical embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and can be variously modified as follows, for example.

In the above-described embodiment, an example in which the foreign matter detecting device 1 detects the epoxy resin adhering to the outer wall portion of the connector 82 made of PBT resin and the surface of the bush 81 made of steel plate as the foreign matter 90 has been described. Not limited to this. For example, the foreign matter detecting device 1 in the above-described embodiment can detect metal powder, hair, and the like adhering to the surface of the epoxy resin injected into the resin injection unit 72 by using the object 80 to be inspected as the resin injection unit 72.

In this way, the foreign matter detecting device 1 can detect various foreign matters 90 made of a material different from that of the inspected object 80 adhering to the inspected object 80. In this case, the foreign matter detection device 1 includes a light generation unit 10 capable of irradiating an appropriate excitation light according to the spectral reflectance of the object 80 and the foreign matter 90, and a filter unit 20 that transmits light in an appropriate wavelength range. And, the light detection unit 30 capable of detecting the light transmitted through the filter unit 20 can be adopted.

Further, in the above-described embodiment, an example in which the photodetector 30 is composed of an image sensor and a CCD camera having an image sensor has been described, but the present invention is not limited thereto. For example, the photodetector 30 may be composed of a photomultiplier tube or the like.

Further, in the above-described embodiment, an example in which the light generating unit 10 irradiates excitation light in the wavelength range of visible light has been described, but the present invention is not limited to this. The foreign matter detection device 1 may employ a light generation unit 10 capable of irradiating excitation light having a wavelength range shorter than the wavelength range of visible light or excitation light having a wavelength range longer than the wavelength range of visible light.

Further, in the above-described embodiment, an example in which the light generating unit 10 can irradiate excitation light having a wavelength of 405 nm within the wavelength range of visible light has been described, but the present invention is not limited to this. The foreign matter detection device 1 employs a light generator 10 capable of irradiating excitation light having a wavelength shorter than 405 nm or excitation light having a wavelength longer than 405 nm in a range shorter than the intermediate wavelength value of visible light in the wavelength range of visible light. It may have been. Further, the foreign matter detection device 1 may employ a light generation unit 10 capable of irradiating excitation light having a wavelength longer than the wavelength intermediate value of visible light within the wavelength range of visible light.

Further, in the above-described embodiment, the foreign matter determination unit 40 attaches the foreign matter 90 to the object to be inspected 80 based on the number of pixels indicating the foreign matter 90 among the pixels constituting the image captured by the light detection unit 30. An example of determining the presence or absence has been described, but the present invention is not limited to this. For example, the foreign matter determination unit 40 may calculate the surface area of the foreign matter 90 from the image captured by the light detection unit 30 and determine whether or not the foreign matter 90 adheres to the object to be inspected 80 based on the surface area of the foreign matter 90. Good.

Further, in the above-described embodiment, the foreign matter determination unit 40 performs a binarization process on the shading image and extracts pixels indicating the foreign matter 90 from the image after the binarization process to obtain the object 80. An example of determining the presence or absence of adhesion of the foreign matter 90 has been described, but the present invention is not limited to this.

For example, the foreign matter determination unit 40 performs pattern matching processing to detect an image similar to the reference image from the images captured by the light detection unit 30, and thus whether or not the foreign matter 90 adheres to the object to be inspected 80. May be configured to be determinable. Further, the foreign matter determination unit 40 compares the image of the object to be inspected 80 captured by the light detection unit 30 with the image of the normal product captured by the light detection unit 30 in advance, and detects the difference between the images to be inspected. It may be configured so that it can be determined whether or not the foreign matter 90 is attached to the object 80.

Further, in the above-described embodiment, an example in which the foreign matter detecting device 1 includes the disturbance light suppressing unit 50 has been described, but the present invention is not limited to this. For example, the foreign matter detection device 1 may be configured not to include the ambient light suppression unit 50.

Needless to say, in the above-described embodiment, the elements constituting the embodiment are not necessarily essential except when it is clearly stated that they are essential and when they are clearly considered to be essential in principle.

In the above-described embodiment, when numerical values such as the number, numerical value, amount, range, etc. of the components of the embodiment are mentioned, when it is clearly stated that it is particularly essential, and in principle, it is clearly limited to a specific number. Except as the case, it is not limited to the specific number.

In the above-described embodiment, when referring to the shape, positional relationship, etc. of a component or the like, the shape, positional relationship, etc., unless otherwise specified or limited in principle to a specific shape, positional relationship, etc. Not limited to, etc.

(Summary)
According to the first aspect shown in part or all of the above-described embodiment, the foreign matter detecting device for detecting the foreign matter adhering to the inspected object is light in a predetermined wavelength range with respect to the inspected object and the foreign matter. By irradiating the excitation light, the light generating part that emits fluorescence that is light in a wavelength range different from the excitation light from the object to be inspected and the foreign matter, and the fluorescence emitted from the object to be inspected and the foreign matter are incident in advance. A filter unit that blocks fluorescence in the first wavelength range, which is a defined wavelength range of light, and transmits fluorescence in a second wavelength range different from the first wavelength range, and a light detection unit that detects light transmitted through the filter unit. It is provided with a foreign matter determination unit for determining the presence or absence of foreign matter adhering to the object to be inspected based on the detection signal detected by the optical detection unit. Of the wavelength range of fluorescence incident on the filter unit, when the wavelength range in which the amount of fluorescence emitted from a foreign substance is larger than the reference amount compared to the amount of fluorescence emitted from the object to be inspected is set as the specific range. The first wavelength range includes at least a part of the wavelength range of fluorescence incident on the filter unit excluding the specific range, and the second wavelength range includes at least a part of the specific range. ..

According to the second aspect, the light generating unit irradiates the excitation light in the wavelength range of visible light.

According to this, the user can visually confirm the light emitted from the light generating portion. In addition, the foreign matter detection device does not require any measures for suppressing the user from being irradiated with the excitation light.

According to the third viewpoint, the light generating unit sets the wavelength intermediate value between the lower limit value of the visible light wavelength range and the upper limit value of the visible light wavelength range as the wavelength intermediate value of visible light. In comparison, excitation light in a wavelength range close to the lower limit of the visible light wavelength range is irradiated.

According to this, since the foreign matter detection device employs a light generation unit capable of irradiating excitation light having a larger optical energy than excitation light having a wavelength longer than the intermediate wavelength value, the light detection unit is radiated from the foreign matter. Fluorescence can be detected stably. Therefore, the foreign matter detecting device stabilizes the foreign matter adhering to the object to be inspected as compared with the case where the light generating part irradiates the excitation light having a wavelength longer than the intermediate wavelength value to detect the fluorescence emitted from the foreign matter. Can be detected.

According to the fourth aspect, the photodetector is configured to capture the object to be inspected and the foreign matter by converting the detected light into an electric signal, and to output the captured image to the foreign matter determination unit. The foreign matter determination unit extracts pixels indicating foreign matter from the pixels constituting the image captured by the photodetector, and determines whether or not foreign matter adheres to the object to be inspected based on the number of pixels indicating foreign matter. ..

According to this, the foreign matter detection device determines a predetermined foreign matter, for example, even if foreign matter adheres to the object to be inspected, if the number of pixels indicating the foreign matter is within the permissible range, the foreign matter to be inspected is normally determined. Depending on the number, it is possible to determine whether or not foreign matter is attached to the object to be inspected.

Further, since the foreign matter detecting device can determine the presence or absence of foreign matter adhering to the object to be inspected based on the number of pixels indicating the foreign matter, it is possible to quantitatively determine the presence or absence of foreign matter adhering to the inspected object. It can be carried out.

According to the fifth aspect, the foreign matter detecting device includes a disturbance light suppressing part that suppresses light other than fluorescence emitted from the object to be inspected and the foreign matter from entering the light detecting part. According to this, the foreign matter is prevented. Since the detection device can suppress the incident of ambient light on the light detection surface of the light detection unit, the foreign matter determination unit is a foreign matter on the object to be inspected as compared with the case where the disturbance light suppression unit is not provided. It is possible to suppress erroneous determination of adhesion.

10 Light generator 20 Filter unit 30 Photodetector 40 Foreign matter judgment unit

Claims (5)

A foreign matter detection device that detects foreign matter (90) adhering to the object to be inspected (80).
By irradiating the object to be inspected and the foreign substance with excitation light having a predetermined wavelength range, the object to be inspected and the foreign substance emit fluorescence having a wavelength range different from the excitation light. Generating part (10) and
The fluorescence emitted from the object to be inspected and the foreign matter is incident, the fluorescence in the first wavelength range which is a predetermined wavelength range of light is blocked, and the fluorescence in a second wavelength range different from the first wavelength range is blocked. The filter unit (20) that transmits fluorescence and
A photodetector (30) that detects the light transmitted through the filter unit and
A foreign matter determination unit (40) for determining the presence or absence of the foreign matter adhering to the object to be inspected based on the detection signal detected by the light detection unit is provided.
Among the wavelength ranges of the fluorescence incident on the filter unit, a wavelength range in which the amount of the fluorescence emitted from the foreign substance is larger than the reference amount is specified as compared with the amount of the fluorescence emitted from the object to be inspected. When it is in the range
The first wavelength range includes at least a part of the wavelength range of the fluorescence incident on the filter unit, excluding the specific range.
The second wavelength range is a foreign matter detection device that includes at least a part of the specific range. The foreign matter detecting device according to claim 1, wherein the light generating unit irradiates the excitation light in the wavelength range of visible light. When the wavelength intermediate between the lower limit value of the wavelength range of visible light and the upper limit value of the wavelength range of visible light is set as the wavelength intermediate value of visible light, the light generating unit of visible light is compared with the wavelength intermediate value. The foreign matter detection device according to claim 2, wherein the excitation light in a wavelength range close to the lower limit of the wavelength range is irradiated. The photodetector is configured to capture the object to be inspected and the foreign matter by converting the detected light into an electric signal, and to output the captured image to the foreign matter determination unit.
The foreign matter determination unit extracts pixels indicating the foreign matter from the pixels constituting the image captured by the light detection unit, and based on the number of pixels indicating the foreign matter, the foreign matter with respect to the object to be inspected. The foreign matter detecting device according to any one of claims 1 to 3, which determines the presence or absence of adhesion of the foreign matter. In any one of claims 1 to 4, the disturbance light suppressing unit (50) for suppressing the light other than the fluorescence emitted from the object to be inspected and the foreign matter from entering the photodetecting unit is provided. The foreign matter detection device described.