JP2023015793A - Optical inspection device, optical inspection method for specimen, and optical inspection method for shape of specimen - Google Patents

Abstract

To provide an optical inspection device that can inspect a change in the state of a specimen such as inclination even if the specimen is sealed inside a container body.SOLUTION: According to an embodiment, an optical inspection device has a container, an image forming optical system, a color filter, and an imaging unit. The container has a container body in which a specimen is contained, and an observation window that has a pair of parallel surfaces passing light from the specimen. The color filter is arranged rotationally symmetrically with respect to an optical axis of the image forming optical system and provided on a focal plane of the image forming optical system. The color filter has a first wavelength selection filter that passes a beam with a first wavelength from the specimen, and a second wavelength selection filter that is formed on an outer periphery of the first wavelength selection filter and passes a beam with a second wavelength from the specimen. The imaging unit is provided on an image forming plane of the image forming optical system, and picks up images of the first wavelength passing through the first wavelength selection filter and the second wavelength passing through the second wavelength selection filter.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD Embodiments of the present invention relate to an optical inspection apparatus, an optical inspection method for an object to be inspected, and an optical inspection method for the shape of an object to be inspected.

For example, the three-dimensional shape is measured by white light interferometry, laser confocal method, or the like.

Japanese Unexamined Patent Application Publication No. 2002-107118 U.S. Pat. No. 3,013,467

The problem to be solved by the present invention is to provide an optical inspection apparatus capable of inspecting changes in the state of a specimen, such as tilt, even when the specimen is sealed in a container body, and an optical inspection of the specimen. To provide a method and method for optical inspection of the shape of a specimen.

According to an embodiment, an optical inspection device has a container, imaging optics, a color filter, and an imaging unit. The container has a container body in which the test object is accommodated, and an observation window that separates the inside and the outside of the container body and has a pair of parallel surfaces through which light from the test object passes. The imaging optical system forms an image of the light beam from the subject that has passed through the observation window. The color filter is arranged rotationally symmetrical with respect to the optical axis of the imaging optical system and provided on the focal plane of the imaging optical system. A color filter is provided on the optical axis of the imaging optical system, passes through the imaging optical system, and passes a light beam of a first wavelength from the test object. A second filter, which is formed in an annular shape around the outer periphery of the filter and the first wavelength selection filter, passes through the imaging optical system, and passes a light beam of a second wavelength different from the first wavelength from the test object. wavelength selection filter. The imaging unit is provided on the imaging plane of the imaging optical system, and captures a light beam having a first wavelength that has passed through the first wavelength selection filter and a light beam having a second wavelength that has passed through the second wavelength selection filter. Take an image.

1 is a schematic block diagram showing an optical inspection system according to first and second embodiments; FIG. Schematic diagram showing the arrangement of a camera, a light source, and a container of the optical inspection system according to the first embodiment. FIG. 3 is a schematic diagram showing the relationship between the camera of the optical inspection system shown in FIG. 2 and the test object in the container body; FIG. 4 is a schematic diagram showing a color filter of the camera shown in FIGS. 2 and 3; FIG. FIG. 3 is a schematic diagram for explaining the relationship between the observation window of the container shown in FIG. 2 and the incident and outgoing directions of light; 4A and 4B are schematic diagrams showing an RGB image, an R image, a B image, and a G image when an image of a test object is captured by the imaging unit of the camera of the optical inspection system according to the first embodiment; FIG. 7 is a schematic cross-sectional view of a position along line VII-VII in FIG. 6 when the test object shown as an RGB image in FIG. 6 is considered as a real test object. 5 is a flowchart showing an example of processing for outputting a scattering angle at an object point of a test object based on the color of light rays captured by an imaging unit using the optical inspection system according to the first embodiment; FIG. 4 is a schematic diagram showing a light emission state from a heater used in a container heating section of the optical inspection system according to the first embodiment; 4A and 4B are schematic diagrams showing an RGB image, an R image, a B image, and a G image when an image of a heated test object is captured by the imaging unit of the camera of the optical inspection system according to the first embodiment; FIG. 10 is a schematic cross-sectional view of a position along line XI-XI in FIG. 10 when the test object shown as an RGB image in FIG. 10 is considered as a real test object. 4A and 4B are schematic diagrams showing an RGB image, an R image, a B image, and a G image when an image of a heated test object is captured by the imaging unit of the camera of the optical inspection system according to the first embodiment; FIG. 13 is a schematic cross-sectional view of a position along line XIII-XIII in FIG. 12 when the test object shown as an RGB image in FIG. 12 is considered as a real test object. 4 is a schematic block diagram showing an optical inspection system according to a modification of the first embodiment; FIG. FIG. 5 is a schematic diagram showing the relationship between the camera of the optical inspection system and the test object in the container body according to the modified example of the first embodiment; FIG. 16 is a schematic diagram showing a first color filter arranged in the focal plane of the imaging optics of the camera shown in FIG. 15; FIG. 16 is a schematic diagram showing a second color filter positioned adjacent to the imaging optics of the camera shown in FIG. 15; 8 is a flowchart showing an example of processing for detecting the three-dimensional position of an object point of a test object using the optical inspection system according to the modification of the first embodiment; Schematic diagram showing the arrangement of a camera, a light source, and a container of an optical inspection system according to a second embodiment. Schematic view of a solder material and a surface-mounted component on a Cu substrate in a state where the test object is heated from the side of the optical axis. FIG. 20 is a schematic diagram showing an RGB image, an R image, a B image, and a G image when the test object is imaged by the imaging unit of the camera of the optical inspection system according to the second embodiment in the state shown in FIG. figure. Schematic view of a solder material and a surface-mounted component on a Cu substrate in a state where the test object is heated from the side of the optical axis. FIG. 22 is a schematic diagram showing an RGB image, an R image, a B image, and a G image when the test object is imaged by the imaging unit of the camera of the optical inspection system according to the second embodiment in the state shown in FIG. figure. Schematic view of a solder material and a surface-mounted component on a Cu substrate in a state where the test object is heated from the side of the optical axis. FIG. 24 is a schematic diagram showing an RGB image, an R image, a B image, and a G image when the test object is imaged by the imaging unit of the camera of the optical inspection system according to the second embodiment in the state shown in FIG. figure.

Each embodiment will be described below with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each portion, the size ratio between portions, and the like are not necessarily the same as the actual ones. Also, even when the same parts are shown, the dimensions and ratios may be different depending on the drawing. In the present specification and each figure, the same reference numerals are given to the same elements as those described above with respect to the previous figures, and detailed description thereof will be omitted as appropriate.

(First embodiment)
An optical inspection system 2 according to this embodiment will be described with reference to FIGS. 1 to 13. FIG.

FIG. 1 is a block diagram showing an example of the configuration of an optical inspection system 2 according to this embodiment. As shown in FIG. 1, optical inspection system 2 comprises optical inspection device 4 and display 6 .

The optical inspection device 4 includes an optical device 12 , an imaging section 14 , a container 16 , a light source 18 , a processing circuit 20 and a memory 22 . The optical device 12 and the imaging unit 14 constitute a so-called camera 13 .

As shown in FIG. 2 , the optical device 12 includes an imaging optical system (imaging lens) 32 and a color filter (color aperture) 34 .

The imaging optical system 32 is formed by combining one or more lenses. The imaging optical system 32 forms an image of the light beam from the test object. The optical axis C of the imaging optical system 32 coincides with the optical axis (central axis) of the color filter 34 . The color filter 34 is arranged rotationally symmetrical with respect to the optical axis of the imaging optical system 32 at a focal plane at a distance f with respect to the imaging optical system 32 . The imaging unit 14 is arranged on the optical path of light passing through the imaging optical system 32 and the color filter 34 . The imaging unit 14 is provided on an imaging plane at a distance L (>f) with respect to the imaging optical system 32 .

FIG. 3 is an enlarged view of a part of the optical device 12 and the imaging section 14 shown in FIG. As shown in FIG. 3, for example, a light ray L11 specularly reflected at an object point O of the test object S, and light rays L21 and L31 scattered at appropriate angles are refracted by the imaging optical system 32, and light rays L12, L22, and L32 are imaged on the imaging surface 14a of the imaging unit 14. FIG.

As shown in FIG. 4, the color filter 34 includes a first wavelength selection filter (wavelength selection area) 42, a second wavelength selection filter (wavelength selection area) 44, and a third wavelength selection filter (wavelength selection area). ) 46. The first wavelength selection filter 42, the second wavelength selection filter 44, and the third wavelength selection filter 46 are concentrically formed. The color filter 34 has the property of transmitting light of a specific wavelength (wavelength spectrum) and blocking light of a wavelength outside the specific wavelength for each of the wavelength selection filters 42 , 44 and 46 .

The first wavelength selection filter 42 is formed in a disc shape. A first wavelength selection filter 42 is provided on the optical axis C of the imaging optical system 32 . The first wavelength selection filter 42 passes the light beam of the first wavelength from the test object that has passed through the imaging optical system 32 . In addition, the first wavelength selection filter 42 has a property of shielding without transmitting light having a wavelength different from the first wavelength (specific wavelength).

The second wavelength selection filter 44 is annularly formed around the outer periphery of the first wavelength selection filter 42 . The second wavelength selection filter 44 allows the light beam of the second wavelength different from the first wavelength from the test object that has passed through the imaging optical system 32 to pass therethrough. The radial width of the second wavelength selection filter 44 can be set appropriately. In addition, the second wavelength selection filter 44 has a property of shielding light with a wavelength different from the second wavelength (specific wavelength) without transmitting the light.

The third wavelength selection filter 46 is annularly formed around the outer circumference of the second wavelength selection filter 44 . The third wavelength selection filter 46 passes the light beam of a third wavelength different from the first wavelength and the second wavelength from the test object, which has passed through the imaging optical system 32 . The radial width of the third wavelength selection filter 46 can be set appropriately. In addition, the third wavelength selection filter 46 has a property of shielding without transmitting light having a wavelength different from the third wavelength (specific wavelength).

The color filter 34 has a light shielding portion 48 around the outer circumference of the third wavelength selection filter 46 . The light shielding part 48 is made of, for example, a black plate and holds the third wavelength selection filter 46 . Note that the third wavelength selection filter 46 holds the second wavelength selection filter 44 . The second wavelength selective filter 44 holds the first wavelength selective filter 42 . The color filter 34 may be configured, for example, so that the transmitted wavelength of light changes continuously from the inside to the outside. That is, the color filter 34 is configured so as to circularly pass light of the same wavelength from the inside to the outside with respect to a common center axis, but not to pass light of a different wavelength.

The outer radius of the first wavelength selection filter 42 of the color filter 34 is r1, the outer radius of the second wavelength selection filter 44 is r2, and the outer radius of the third wavelength selection filter 46 is r3. At this time, r3>r2>r1. Here, the area within the radius r1 of the first wavelength selection filter 42 is assumed to be A1. Let A2 be the area between the outer circumference of the first wavelength selective filter 42 and the outer circumference of the second wavelength selective filter 44 . Let A3 be the area between the outer circumference of the second wavelength selective filter 44 and the outer circumference of the third wavelength selective filter 46 .

The radius r1 of the first wavelength selective filter 42, the distance r2-r1 between the outer circumference of the first wavelength selective filter 42 and the outer circumference of the second wavelength selective filter 44, and the second wavelength selective filter 44 r3-r2, which is the distance between the outer circumference of , and the outer circumference of the third wavelength selection filter 46, can be set appropriately. More specifically, the radius r1 of the first wavelength selection filter 42, the radius r2 of the second wavelength selection filter 44, and the radius r3 of the third wavelength selection filter 46 of the color filter 34 can be changed depending on the detection target. . Therefore, the shape and size of the areas A1, A2, A3 may change depending on the detection target.

In the optical device 12 according to the present embodiment, among the light rays emitted from an arbitrary object point O of the test object S, when entering the imaging optical system 32, the chief ray is parallel to the optical axis C (red ( R) Light is separated as a red ray. In other words, the optical device 12 according to this embodiment is a telecentric optical system having telecentricity with respect to red light rays. On the other hand, the optical device 12 according to this embodiment is a non-telecentric optical system that does not have telecentricity with respect to blue (B) light and green (G) light.

In the present embodiment, the optical inspection system 2 detects the contact angles α and β between the base material S1 and the material placed on the base material S1 (brazing material as a melt (liquid)) S2, which will be described later. Used to evaluate wettability. The contact angles α and β depend on, for example, the properties of the material and the temperature of the material. When the contact angles α and β are small, the contact angles α and β are estimated to be in the range of, for example, less than 10°. As an example, in the present embodiment, the color filter 34 can obtain the angle of the scattered light (scattering angle θ) with respect to the optical axis C, for example, in the range of 0° to 3°. r1 of is defined. In the color filter 34, the radius r2 of the second wavelength selection filter 44 is defined so that the angle of the scattered light (scattering angle θ) with respect to the optical axis C can be obtained within a range of 3° to 6°, for example. In the color filter 34, the radius r3 of the third wavelength selection filter 46 is defined so that the angle of scattered light (scattering angle θ) with respect to the optical axis C can be obtained in the range of 6° to 9°, for example.

Light is a kind of electromagnetic waves, and includes X-rays, ultraviolet rays, visible light, infrared rays, microwaves, and the like. In this embodiment, it is assumed that the light is visible light, and that the wavelength is in the range of, for example, 400 nm to 760 nm. In the present embodiment, for the sake of simplicity of explanation, the color filter 34 transmits light of a certain wavelength among visible light, for example, for each of the wavelength selection filters 42, 44, and 46, and transmits light having a wavelength other than a certain wavelength. Shall be shielded, i.e. prevent transmission.

In this embodiment, for convenience, the wavelength of red light is 700 nm, the wavelength of green light is 546.1 nm, and the wavelength of blue light is 435.8 nm.

In this embodiment, the region A1 of the first wavelength selection filter 42 passes visible light, for example, red light (700 nm) and R light having a first wavelength in the vicinity thereof, and filters light of other wavelengths. Cut off. In this embodiment, the area A2 of the second wavelength selection filter 44 passes, among visible light, blue light (435.8 nm) and B light having a second wavelength in the vicinity thereof, and other wavelengths. Block out light. In this embodiment, the region A3 of the third wavelength selection filter 46 passes, among visible light, for example, green light (546.1 nm) and G light having a third wavelength in the vicinity thereof, and light of other wavelengths. block the The first wavelength range passed by the region A1 of the first wavelength selection filter 42, the second wavelength range passed by the region A2 of the second wavelength selection filter 44, and the wavelength range of the third wavelength selection filter 46 It is preferable that the ranges of the third wavelengths passed by the region A3 do not overlap in this embodiment.

The optical device 12 has a half mirror 36 . A half mirror 36 is provided between the imaging optical system 32 and the container 16 . The half mirror 36 illuminates the test object S of the container 16 with illumination light (white light) from the light source 18, and transmits the light from the test object S to enter the imaging optical system 32. .

The imaging unit 14 uses, for example, a so-called RGB camera. The imaging unit 14 can use, for example, a CMOS image sensor or a CCD image sensor.

As shown in FIG. 3, the imaging unit 14 captures the light beam L12 of the first wavelength that has passed through the area A1 of the imaging optical system 32 and the first wavelength selection filter 42, the imaging optical system 32 and the second wavelength selection filter. The light beam L22 of the second wavelength that has passed through the area A2 of the filter 44 and the light beam L32 of the third wavelength that has passed through the area A3 of the imaging optical system 32 and the third wavelength selection filter 46 are imaged.

As shown in FIG. 2, the container 16 includes a container body 62 in which the test object S is accommodated, an observation window 64, and a stage 66 on which the test object S is placed.

The container body 62 is made of, for example, a non-translucent material. It is preferable that the container main body 62 has heat insulating properties to prevent the heat from being transmitted to the outside when the inside is heated. Further, it is preferable that the container body 62 has rigidity to maintain its shape when the internal pressure inside the container body 62 is appropriately reduced by evacuation. In addition, it is preferable that the container body 62 has such rigidity that it maintains its shape when gas is introduced and the internal pressure inside the container body 62 is appropriately increased.

The container main body 62 has an opening edge 62 a for taking the specimen S into and out of the container main body 62 . The opening edge 62a is formed, for example, in an annular shape on the upper surface of the container body 62, for example.

The opening edge 62 a allows observation of the test object S on the stage 66 from the outside of the container body 62 . The opening diameter of the opening edge 62a is, for example, about 150 mm. The distance from the opening edge 62a to the stage 66 is, for example, about 500 mm.

The observation window 64 is detachably fixed to the opening edge 62 a of the container body 62 . A glass plate, for example, is used for the observation window 64 . The observation window 64 is preferably formed so that deformation can be ignored when the internal pressure inside the container body 62 is increased or decreased appropriately.

It is preferable that the inside of the container body 62 is sealed when the observation window 64 is attached to the opening edge 62a of the container body 62 . Therefore, the observation window 64 separates the inside and outside of the container body 62 while attached to the container body 62 .

As shown in FIG. 5, the observation window 64 has a pair of parallel surfaces 64a, 64b. When light is incident on the test object S inside the container body 62 from the outside, the incident angle θ11 of the incident light on the parallel surface 64a facing the outside of the container body 62 and the emission angle through the parallel surface 64b facing the inside are θ12 becomes parallel. Further, when the light is reflected by the test object S of the container body 62 and is emitted from the inside of the container body 62 to the outside, the incident angle θ21 of the emitted light to the inner parallel surface 64b and the outer parallel surface 64a are is parallel to the exit angle .theta.22. Therefore, the normal direction of the pair of parallel surfaces 64a and 64b of the observation window 64 does not have to match the incident direction of the light beam.

As shown in FIG. 2, the stage 66 is provided within the container body 62 . In this embodiment, the stage 66 is arranged directly below the observation window 64 on the upper surface of the container body 62 . The optical device 12 is arranged above the observation window 64 . A half mirror 36 is arranged between the imaging optical system 32 of the optical device 12 and the observation window 64 . The half mirror 36 reflects the light from the light source 18, illuminates the test object S on the stage 66 through the observation window 64, illuminates the test object S, and transmits the reflected light passing through the observation window 64 to the half mirror. It enters the imaging optics 32 of the optical device 12 through 36 .

Therefore, in the present embodiment, the container 16, the optical device 12, and the imaging unit 14 are arranged along the vertical direction while being separated from each other.

The container 16 has a heating section 72 that heats the test object S, a temperature detection section 74 , a vacuum device 76 and a pressure detection section 78 .

The heating unit 72 has a coil 72a that covers the outer periphery of the stage 66, for example. The stage 66 is made of a conductive material such as carbon. Therefore, when a high frequency current is applied to the coil 72a, the stage 66 is heated. The heating unit 72 heats the stage 66 and the test object S placed on the stage 66 by thermal conduction by applying a high-frequency current to the coil 72a.

The container main body 62 , the stage 66 and the observation window 64 are made of a heat-resistant material that suppresses deformation and melting due to heating of the heating section 72 .

The temperature detection unit 74 detects the temperature inside the container body 62 heated by the heating unit 72 . As the temperature detector 74, the temperature inside the container body 62 is measured using, for example, a thermocouple.

The vacuum device 76 has a turbomolecular pump 76a and a rotary pump 76b. These turbo-molecular pump 76a and rotary pump 76b try to discharge the gas inside the container body 62 and evacuate the inside of the container body 62 . In this embodiment, the pressure inside the container body 62 can be reduced to about 10 ⁻³ Pa, for example, by the turbomolecular pump 76a and the rotary pump 76b. As for the decompression device, any device such as an oil diffusion pump, a cryopump, a mechanical booster pump, or a diaphragm pump can be selected.

The pressure sensing portion 78 senses the pressure inside the container body 62 .

In this embodiment, as the test object S, a substrate S1 and a brazing material S2 placed on the substrate S1 are used. The base material S1 is formed in an appropriate shape such as a disk shape or a rectangular shape. If the substrate S1 is disk-shaped, the diameter of the substrate S1 is formed to be, for example, several times larger than the size of the brazing filler metal S2. The diameter of the brazing filler metal S2 in a solid state is, for example, about 10 mm.

A Cu plate material, for example, is used as the base material S1. In this embodiment, on the horizontal plane S11 of the base material S1, for example, an Ag—Cu alloy material called silver solder is placed as the brazing material S2 that can be melted. The melting point of the base material S1 is higher than the melting point of the brazing material S2 as a melt. The heating unit 72 heats the test object S to a temperature higher than the melting point of the brazing material S2 as a molten material and lower than the melting point of the base material S1.

As for the heating device for heating the brazing material S2 on the substrate S1 placed on the stage 66, any heating device such as electromagnetic induction heating, radiation heating, resistance heating, and laser heating can be selected.

As an example, the light source 18 is one that emits white light with appropriate brightness. Therefore, the illumination light from the light source 18 includes red (R) light, green (G) light, and blue (B) light.

The processing circuitry 20 shown in FIG. 1 includes a processor. The processing circuit 20 is, for example, an integrated circuit such as a Central Processing Unit (CPU) or an Application Specific Integrated Circuit (ASIC). A general-purpose computer may be used as the processing circuit 20 . The processing circuit 20 is not limited to being provided as a dedicated circuit, and may be provided as a program executed by a computer. In this case, the program is recorded in a storage area within the integrated circuit, memory 22, or the like. The processing circuitry 20 is connected to the imaging section 14 and the memory 22 . The processing circuit 20 calculates information related to the test object S based on the output of the imaging section 14 .

As shown in FIG. 1 , the processing circuit (first processor) 20 functions as a color extractor 81 and a scattering angle calculator 82 .

The color extractor 81 is an example of a generator. Based on the output of the imaging unit 14 , the color extracting unit 81 outputs the intensity of each of the R light, B light, and G light of the rays that have reached the imaging surface for each pixel of the imaging unit 14 . The color extraction unit 81 separates the image data output from the imaging unit 14 into R, G, and B to generate image data for each color. The color extractor 81 is an example of a generator. Note that extracting colors by the color extraction unit 81 means dividing the RGB image captured by the imaging unit 14 into color channels, or directly extracting a red (R) light image (R image) and a green light image from the imaging unit 14 . (G) light image (G image) and blue (B) light image (B image), ie, the case of acquiring the R, G, and B color channels, respectively.

The scattering angle calculator 82 calculates the object point O of the test object S based on the image data of the R image (first image), G image (second image), and B image (second image). Calculate the relevant information. Specifically, the scattering angle calculator 82 identifies the color of the captured light based on the image data of the R image, the G image, and the B image. The scattering angle calculator 82 calculates the environment at the object point O of the test object S based on the color of the imaged light rays, that is, the intensity of each of the R light, the G light, and the B light of the light reaching the imaging surface 14a. Calculate the light scattering angle. The scattering angle calculator 82 is an example of a calculator. The scattering angle at the object point O of the test object S is an example of information related to the test object S. FIG.

Note that the processing circuit 20 may be outside the optical inspection device 4 . In this case, the output of the imaging unit 14 may be output to the outside of the optical inspection device 4 or recorded in the memory 22 . In other words, the calculation of the information related to the test object S may be performed inside the optical inspection apparatus 4 or may be performed outside.

The memory 22 is non-volatile memory such as flash memory, but may also include volatile memory.

The memory 22 stores the outputs of the imaging section 14 and the processing circuit 20 . The memory 22 stores the focal length f of the imaging optical system 32, the distance L between the imaging optical system 32 and the imaging surface 14a of the imaging unit 14, and a plurality of wavelength selection filters 42, 44 of the color filter 34, 46 arrangement etc. are recorded.

In the memory 22, the relationship between the channel from which the image is obtained and the scattering angle .theta., and the relationship between the scattering angle .theta. In the example of the present embodiment, the scattering angle θ and the contact angle correspond one-to-one (scattering angle θ=contact angle) for simplification of explanation. By measuring the relationship before the experiment, the contact angle can be obtained by, for example, multiplying the scattering angle θ by an appropriate coefficient (not limited to a natural number). As an example, the scattering angle θ may be twice the contact angle.

Therefore, the radii r1, r2, r3 of the color filter 34 with respect to the optical axis C are set according to the relationship between the scattering angle θ and the contact angle.

A display 6 displays the output of the processing circuit 20 . The output of the processing circuit 20 includes, for example, an image based on the image data output from the imaging unit 14, an operation screen, and the like. The display 6 is, for example, a liquid crystal display or an organic EL display. Note that the display 6 may not be provided. In this case, the output of the processing circuit 20 may be recorded in the memory 22, displayed on a display provided outside the optical inspection system 2, or recorded in a memory provided outside the optical inspection system 2. good.

Using the optical inspection apparatus 4 according to the present embodiment, the inside of the container 16 is heated, the brazing material S2 is melted, and the test for measuring the contact angle with respect to the plane S11 of the substrate S1 when liquefied, and the substrate A test was conducted to detect the shape of the brazing material S2 with respect to S1.

Here, the incident position of the specularly reflected light component from the test object S on the imaging surface 14a and the wavelength that can pass through the color filter 34 do not depend on the distance from the test object S. FIG. This is because an image that passes through the imaging optical system 32 as parallel light with respect to the optical axis C is captured as an R image by the color filter 34 in this embodiment. The R image does not depend on the distance from the object S to be inspected.

On the other hand, the incident position of the scattered light component from the test object S on the imaging surface 14a and the wavelength that can pass through the color filter 34 change depending on the distance from the test object S. FIG. For example, even if the scattering angle .theta. is small, if the distance from the camera 13 is long, the light with the scattering angle .theta. In this case, an image of that scattering angle cannot be obtained.

Therefore, the positional relationship (distance) between the subject S and the camera 13 is adjusted to adjust the relationship between the scattering angle θ and the contact angle. The relationship between the scattering angle θ and the contact angle based on the positional relationship (distance) between the subject S and the camera 13 can be obtained in advance through experiments.

As described above, in the example of the present embodiment, for simplification of explanation, the object S and the camera 13 are arranged such that the scattering angle θ and the contact angle correspond one-to-one (scattering angle θ=contact angle). Adjust the positional relationship with Then, the processing circuit 20 causes the memory 22 to store the relationship between the scattering angle θ and the contact angle.

As shown in FIG. 2, a base material S1 and 0.2 g of brazing material S2 were placed on a stage 66 directly below the observation window 64 of the container 16 . Illumination light from the light source 18 is applied to the test object S (the base material S1 and the brazing material S2 on the base material S1) through the half mirror 36 and the observation window 64, and the reflected light from the test object S is emitted. , the observation window 64, and the camera 13 through the half mirror 36. Here, an image (RGB image) of the base material S1 and the brazing material S2 on the base material S1 is acquired using the camera 13 through the observation window 64 supported by the container body 62, and is shown in FIG. An RGB image and/or a red light image (R image), a blue light image (B image), and a green light image (G image) were displayed on the display 6 . When the test object S shown as an RGB image in FIG. 6 is considered as a real object, the cross section of the test object S along the line VII-VII in FIG. 6 is roughly formed as shown in FIG. Assume that

The operation of the processing circuit 20 will now be described with reference to FIG. FIG. 8 is a flowchart showing an example of calculation processing according to this embodiment. In the calculation process, the processing circuit 20 calculates information related to the object point O on the subject S based on the output of the imaging unit 14 .

In step ST11, the processing circuit 20 as the color extraction section 81 acquires the intensity of each RGB of the light rays emitted from an arbitrary object point O and incident on the imaging surface 14a based on the output of the imaging section 14. FIG. As a result, the image data is color-separated into an R image, a B image, and a G image.

In step ST12, the processing circuit 20 as the color extractor 81 identifies the color (hue) of the light beam that has exited from an arbitrary object point O and entered the imaging surface 14a.

At step ST13, the processing circuit 20 as the scattering angle calculator 82 calculates the scattering angle θ of the ambient light at the object point O based on the specified color of the light. Here, in the optical device 12 according to this embodiment, the plurality of wavelength selection filters 42, 44, 46 of the color filter 34 are arranged concentrically. That is, in the optical device 12 , the regions A1, A2, A3 of the plurality of wavelength selection filters 42 , 44 , 46 of the color filter 34 are rotationally symmetrical about the optical axis C of the imaging optical system 32 . Therefore, the light rays are color-separated according to the scattering angle θ at an arbitrary object point O. Therefore, according to the scattering angle θ at the object point (surface) O of the object S, a red light image (R image), a blue light image (B image), and a green light image (G image) are spectrally separated.

The processing circuit 20 as the scattering angle calculator 82 calculates that the scattering angle θ at the object point O satisfies 0≦θ<θr when the specified color of the light ray is red (R light). At this time, θ is, for example, 0° or more and less than 3°. The processing circuit 20 as the scattering angle calculator 82 calculates that the scattering angle θ at the object point O satisfies θr≦θ<θb when the specified color of the light ray is blue (B light). At this time, θ is, for example, 3° or more and less than 6°. The processing circuit 20 as the scattering angle calculator 82 calculates that the scattering angle θ at the object point O satisfies θb≦θ<θg when the specified color of the light ray is green (G light). At this time, θ is, for example, 6° or more and less than 9°.

Thus, the processing circuit 20 of the optical inspection system 2 according to this embodiment can output the scattering angle θ at the object point O based on the color of the imaged light rays.

In this embodiment, the correspondence between the scattering angle θ and the contact angle is stored in the memory 22 in advance. Here, there is a one-to-one correspondence between the scattering angle θ and the contact angle. That is, the color filter 34 is arranged with respect to the test object S so that the scattering angle θ=contact angle. Therefore, the processing circuit 20 can obtain the contact angle corresponding to the scattering angle θ by calculating the scattering angle θ.

The container 16 shown in FIG. 2 has an observation window 64 through which the light beam generated by the light source 18 can be transmitted to irradiate the test object S, and through which the reflected light from the test object S can be transmitted. The normal direction of this observation window 64 does not have to match the incident direction of the light beam. This is because, as shown in FIG. 5, the direction of the light beam incident on the observation window 64 does not change before and after passing through the object. Therefore, even in a heating furnace in which parallel planes 64a and 64b of the observation window 64 are tilted with respect to the optical axis of the optical device 12, an image of the specimen S can be obtained through the observation window 64 according to the present embodiment. can be done.

The container body 62 and the observation window 64 shown in FIG. And the angle of emission toward the brazing material S2 does not change. Alternatively, the change in incident and exit angles is negligibly small. Further, the incident angle at which the reflected light from the base material S1 and the brazing material S2 is incident on the observation window 64 and the emission angle from the observation window 64 toward the optical device 12 do not change. Alternatively, the change in incident and exit angles is negligibly small. Therefore, even if the container 16 used as a heating furnace has the container main body 62 and the observation window 64 according to the present embodiment, the base material S1 and the brazing material S2 of the test object S can be measured using the optical device 12. can be obtained.

In this embodiment, the optical axis C of the optical device 12 is adjusted so that the light from the plane S11 of the substrate S1 on which the brazing material S2 is placed passes through the center of the color filter 34 based on the illumination light from the light source 18. do. That is, the plane S11 of the substrate S1 is orthogonal to the optical axis C. As shown in FIG. At this time, the camera 13 obtains an RGB image shown in FIG. Also, a red light image (R image), a blue light image (B image), and a green light image (G image) are obtained by the color extraction unit 81 of the processing circuit 20 . The B image and the G image are obtained as a black image on the plane S11 of the substrate S1. In the R image, the shape of the plane S11 of the substrate S1 is obtained as a bright color. Incidentally, when the scattered light of the brazing material S2 is incident on any one of the first wavelength selection filter 42, the second wavelength selection filter 44, and the third wavelength selection filter 46 of the color filter 34, the R image, When the B image and the G image are added together, an RGB image is obtained. In the case of this embodiment, part of the light scattered by the brazing filler metal S2 is incident on the light shielding portion 48 of the color filter 34 . Therefore, there may be a portion of the brazing material S2 that cannot be imaged by the imaging unit 14 .

The specularly reflected light component (bright portion) of the brazing material S2 can be obtained as part of the R image together with the plane S11 of the substrate S1. In the R image, the scattered light component, which is not the specularly reflected light component, of the brazing material S2 becomes a black image (black area). Scattered light is obtained as a B image and/or a G image depending on the scattering angle. In the B image, the specularly reflected light component of the brazing material S2 forms a black image. Further, in the B image, the portion of the brazing material S2 that is obtained as the G image is a black image. In the G image, the specularly reflected light component of the brazing material S2 becomes a black image. Further, in the G image, the portion of the brazing material S2 that is obtained as the B image is a black image.

After the operator checks the display 6 that the plane S11 of the base material S is displayed as a bright portion in the R image, the inside of the container body 62 is evacuated using the vacuum device 76 . The operator waits until the degree of vacuum becomes 10 ⁻³ Pa or less, for example, when the pressure in the container body 62 is detected by the pressure detection unit 78 .

As a result of detection by the pressure detection unit 78, the degree of vacuum in the container body 62 becomes 10 ⁻³ Pa or less. is heated, and based on the image captured by the camera 13, the optical inspection device 4 is used to start measuring the angle information of the contact angle between the base material S1 and the brazing material S2.

The container body 62 and the observation window 64 emit white light from the light source 18 to the observation window 64, regardless of the degree of vacuum, provided that the temperature inside the container body 62 is within the temperature at which the brazing material S2 is melted, for example. The angle of incidence of light and the angle of emission from the observation window 64 toward the base material S1 and the brazing material S2 are parallel and do not change. Alternatively, the change in the incident angle and the exit angle is so small that it can be ignored, and the incident angle and the exit angle can be regarded as parallel. Further, the incident angle at which the reflected light from the base material S1 and the brazing material S2 is incident on the observation window 64 and the emission angle from the observation window 64 toward the optical device 12 are parallel and do not change. Alternatively, the change in the incident angle and the exit angle is so small that it can be ignored, and the incident angle and the exit angle can be regarded as parallel. Therefore, even if the container 16 used as a heating vacuum furnace has the container main body 62 and the observation window 64 according to the present embodiment, the camera 13 can be used to detect the base material S1 and the brazing material S2 of the test object S. can be obtained.

For example, a temperature detector (thermocouple) 74 measures the temperature inside the container body 62 . The operator confirms that the brazing material S2 on the flat surface S11 of the base material S1 reaches about the melting point (here, 780° C.).

In the light source 18 according to the present embodiment, the intensity of the light with which the test object S is irradiated is higher than the intensity of the light emitted by the heat generated by the coil 72 a of the heating unit 72 . Then, when the coil 72a is heated to, for example, 780° C., the coil 72a emits red light. As shown in FIG. 9, the peak wavelength of the light emitted from the coil 72a at this time is longer than red light (700 nm), for example, about 3000 nm, and is in the infrared region. Here, as described above, the first wavelength selection filter 42 of the color filter 34 passes R light but blocks light of other wavelengths, and the second wavelength selection filter 44 passes B light, Light of other wavelengths is cut off, and the third wavelength selection filter 46 passes G light, but cuts off light of other wavelengths. Therefore, each wavelength selection filter 42, 44, 46 of the color filter 34 is formed so as to shield the peak wavelength (for example, 3000 nm) of the light emitted from the heating section 72 when the heating section 72 is heated. . Therefore, in the present embodiment, most of the wavelengths of light generated by the heating unit 72 do not pass through the color filter 34 . Therefore, when imaging the subject S, the imaging unit 14 is prevented from being affected by the light emission of the heating unit 72 .

The contact angle of the brazing filler metal S2 on the plane S11 of the substrate S1 gradually decreases as the melting progresses. The contact angle α or the contact angle β at the time when the brazing filler metal S2 on the plane S11 of the substrate S1 is melted and the expansion of the droplet on the plane S11 of the substrate S1 is stopped is defined as the final contact angle.

As shown in FIGS. 10 to 13, the contact angle of the brazing filler metal S2 with respect to the plane S11 of the substrate S1 is acute in this embodiment. Depending on the magnitude of the contact angle, the position where the reflected light (scattered light) from the brazing material S2 is incident on the imaging optical system 32 changes, and the image captured by the imaging unit 14 through the color filter 34 changes. do.

FIG. 10 is an example of RGB images and/or R, B, and G images when the scattering angle θ (contact angle) is α (>β). 10 as an RGB image, the cross section of the test object S along line XI--XI in FIG. 10 is roughly formed as shown in FIG. Assume that FIG. 12 is an example of an RGB image and/or an R image, a B image, and a G image when the scattering angle θ (contact angle) is an angle β (<α). When the test object S shown as an RGB image in FIG. 13 is considered as a real object, the cross section of the test object S along the line XIII-XIII in FIG. 12 is roughly formed as shown in FIG. Assume that

As shown in FIG. 11, when the contact angle α is larger than the contact angle β shown in FIG. 13, as shown in FIG. Then, the brazing material S2 is obtained, for example, as an R image captured through the central first wavelength selection filter 42 and a G image captured through the third wavelength selection filter 46 . It should be noted that there are cases in which an R image is not obtained for the portion of the brazing material S2, and a B image is obtained.

The memory 22 preliminarily stores the correspondence relationship between the scattering angle θ and the inclination of the test object S (here, the contact angle α or the contact angle β). Therefore, when it is recognized that the boundary between the plane S11 of the base material S1 and the brazing material S2 is obtained as part of the G image, the processing circuit 20 determines that the scattering angle θ is between θb≦θ<θg and output. The processing circuit 20 reads the contact angle α of the boundary between the plane S11 of the base material S1 and the brazing material S2 corresponding to the scattering angle θ, and outputs the contact angle α to the display 6 .

When the brazing filler metal S2 is melted and liquefied, and the contact angle α becomes smaller as shown in FIG. An R image captured through the first wavelength selection filter 42 and a B image captured through the second wavelength selection filter 44 are obtained. It should be noted that there are cases in which an R image is not obtained for the portion of the brazing material S2, but a G image is obtained.

Therefore, when it is recognized that the boundary between the plane S11 of the substrate S1 and the brazing material S2 is obtained as part of the B image, the processing circuit 20 determines that the scattering angle θ is between θr≦θ<θb. and output. The processing circuit 20 reads out the contact angle β of the boundary between the plane S11 of the substrate S1 and the brazing material S2 corresponding to the scattering angle θ, and outputs the contact angle β to the display 6 .

When it is recognized that the boundary between the plane S11 of the substrate S1 and the brazing material S2 is obtained as part of the R image, the processing circuit 20 outputs that the scattering angle θ is between 0≦θ<θr. . The processing circuit 20 reads out the contact angle of the boundary between the plane S11 of the substrate S1 and the brazing material S2 corresponding to the scattering angle θ, and outputs the contact angle to the display 6 . In this case, the contact angle is 0<β.

Thus, the contact angle can be estimated using the optical inspection system 2 according to this embodiment. That is, in the example according to the present embodiment, when the boundary between the plane S11 of the base material S1 and the brazing material S2 is obtained as a G image as shown in FIG. is output to, for example, the display 6, and the boundary between the plane S11 of the substrate S1 and the brazing material S2 is obtained as a B image as shown in FIG. is output to the display 6. Further, when the boundary between the plane S11 of the substrate S1 and the brazing material S2 is obtained as an R image, the processing circuit 20 outputs to the display 6 that the contact angle is smaller than the angle β.

Therefore, according to the present embodiment, for example, changes in the state of the specimen S in the container 16 can be observed through the observation window 64 of the container 16 while the container 16 is operated as a heating furnace or a vacuum heating furnace. You can continue to observe with touch. Then, the contact angle of the brazing material S2 with respect to the substrate S1 of the test object S in the container 16 can be measured by photographing the container 16 containing the test object S from above. Therefore, by using the optical inspection system 2 according to the present embodiment, the wettability (contact angle) of the brazing material S2 with respect to the base material S1 can be evaluated by real-time monitoring without taking out the specimen S from the container body 62. be able to.

Thus, by using the optical inspection device 4 according to the present embodiment and the optical inspection system 2 including the optical inspection device 4, it is possible to perform an element test of each material before applying it to a product, for example.

In this embodiment, an example in which the camera 13 is arranged directly above the observation window 64 of the container 16 and the test object S in order to melt and liquefy the brazing material S2 of the test object S on the base material S1 has been described. If it is not necessary to melt a part of the test object S and the test object S can be maintained on the stage 66, for example, the camera 13 needs to be arranged directly above the observation window 64 of the container 16 and the test object S. no. For this reason, the optical axis C of the camera 13 may be allowed to be in any direction, not along the vertical direction, depending on the required test.

In the present embodiment, an example in which the white light from the light source 18 is applied to the test object S through the observation window 64 via the half mirror 36 has been described. The light source 18 and the half mirror 36 may not be necessary if the subject S is irradiated with sunlight or other light in an amount necessary for the imaging unit 14 to obtain an image. . In addition to sunlight or other light, if the amount of light required for the imaging unit 14 to obtain an image of the test object S can be obtained by, for example, heating by the heating unit 72, the light source 18 is unnecessary. can be. In addition, as shown in FIG. 7, generally, the heating unit 72 can emit light in the infrared and visible light regions as the temperature of the coil 72a increases. When the temperature of the coil 72a further increases, the heating unit 72 can emit light in the ultraviolet region in addition to infrared light and visible light.

In this embodiment, the amount of light from the light source 18 is made larger than the amount of light from the heating section 72 . For example, when the amount of light from the heating unit 72 is relatively large compared to the amount of light from the light source 18, for example, between the observation window 64 and the half mirror 36, or between the half mirror 36 and the imaging optical system 32 , for example, a second color filter that cuts the wavelength of the light from the heating unit 72 may be arranged. At this time, the second color filter is used as a filter that cuts wavelengths different from those of the first wavelength selection filter 42, the second wavelength selection filter 44, and the third wavelength selection filter 46, for example. As the second color filter, a filter that cuts wavelengths around 600 nm, which are different from the wavelengths of R light, B light, and G light, is used.

The optical inspection apparatus 4 according to the present embodiment measures the image of the substrate S1 and the brazing material S2 on the plane S11 of the substrate S1 at room temperature before heating, during heating, and when reaching a desired temperature of several hundred degrees Celsius or higher. can be obtained through observation window 64. It is possible to observe through the observation window 64 of the container 16 how the brazing material S2 melts. Therefore, it is possible to continuously observe the state of the specimen S inside the container 16, which is at a high temperature of several hundred degrees centigrade or higher. Therefore, it is possible to acquire the shape change of the test object S corresponding to the temperature due to heating.

Further, the processing circuit 20 can measure the contact angle of the brazing material S2 with respect to the plane S11 of the substrate S1 by performing image processing when the brazing material S2 reaches its melting point. Therefore, the user of the optical inspection device 4 can evaluate the wettability of the brazing filler metal S2 to the plane S11 of the substrate S1.

In this embodiment, the case where the inside of the container 16 is heated has been described as an example. Even when the inside of the container 16 is cooled to −196° C. or less by liquid nitrogen, for example, the optical inspection apparatus 4 according to the present embodiment can be used to detect the state change of the specimen S according to the temperature change. can be obtained.

According to the present embodiment, even if the inside of the container body 62 is heated to an appropriate temperature such as several hundred degrees Celsius, or cooled to an appropriate temperature such as -196 degrees Celsius or lower, heating / It is possible to provide an optical inspection device 4 capable of calculating the inclination (contact angle) of the specimen S in the container 16 without being affected by the temperature due to cooling, and a method for calculating the inclination of the specimen S. can.

Therefore, according to the present embodiment, for example, even when the test object is enclosed in the container main body 62, the optical inspection apparatus can inspect the state change such as the inclination (contact angle) of the test object S. 4, and optical inspection methods such as calculating the inclination (contact angle) of the test object S can be provided.

The radius r1 of the first wavelength selection filter 42, the radius r2 of the second wavelength selection filter 42, and the radius r3 of the third wavelength selection filter 46 of the color filter 34 according to this embodiment can be set appropriately. is. For example, if the contact angle θ is assumed to be relatively small, the scattering angle is also assumed to be small. In this case, by appropriately setting the imaging optical system 32 or appropriately setting the radius r1 defining the area A1, the radius r2 defining the area A2, and the radius r3 defining the area A3, Scattered light from the brazing material S2 of the specimen S is made incident on the regions A2 and A3. For example, if the contact angle θ is assumed to be relatively large, the scattering angle is also assumed to be large. In this case, by appropriately increasing the radius r1 that defines the region A1 and arranging the regions A2 and A3 relatively far from the optical axis C, the scattered light from the brazing material S2 of the test object S is It is made to be incident on A2 and A3. Therefore, by appropriately setting the imaging optical system 32 and/or the color filter 34 according to the subject S, the processing circuit 20 can output a desired contact angle.

In addition to changing the radii r1, r2, r3 of the color filter 34 according to the assumed contact angle, angle information can also be obtained by adjusting the positional relationship (distance) between the test object S and the camera 13. An image that has passed through the color filter 34 can be acquired by the imaging unit 14 .

In this embodiment, an example of using an RGB camera as the imaging unit 14 has been described. It is also preferable to use a multispectral camera or a hyperspectral camera as the imaging unit 14 . The color filter 34 can be finely concentrically divided into regions for each wavelength to pass, in addition to the regions A1, A2, and A3 of the three wavelength selection filters 42, 44, and 46 described above. Therefore, by increasing the number of regions through which different wavelengths pass in the color filter 34 to four or more and increasing the number of obtained images for each scattering angle θ to four or more, the processing circuit 20 can output the contact angle in more detail. be able to.

Further, in the present embodiment, the color filter 34 includes a first wavelength selection filter (wavelength selection area) 42, a second wavelength selection filter (wavelength selection area) 44, and a third wavelength selection filter (wavelength selection area ) 46 has been described. The color filter 34 may comprise at least two regions, for example, a first wavelength selection filter (wavelength selection region) 42 and a second wavelength selection filter (wavelength selection region) 44 . In this case, the processing circuit 20 can obtain the scattering angles θ in the two angular ranges of 0≦θ<θr and θr≦θ<θb, and obtain the contact angles corresponding to the scattering angles θ.

An example in which the color filter 34 of the present embodiment is formed as a region through which R light, B light, and G light pass from the inside to the outside has been described. For example, the color filters 34 are appropriately formed such that they are formed as areas through which B light, G light, and R light pass from the inside toward the outside.

(Modification)
There are various methods for detecting the three-dimensional position of the object point O of the test object S in the optical inspection system 2 according to the first embodiment. Here, an example of a method for detecting the three-dimensional position of the object point O of the test object S will be mainly described as a modified example of the first embodiment with reference to FIGS. 14 to 18. FIG.

An optical inspection system 2 according to this modification will be described.

As shown in FIG. 14, a processing circuit (second processor) 20 according to this modification includes a color extraction unit 81, an image plane position acquisition unit 83, and a scattering angle calculation unit 82 described in the first embodiment. , and an object point position calculator 84 .

The image plane position acquisition unit 83 and the object point position calculation unit 84 are examples of a calculation unit. The calculator calculates information about the test object including the object point O based on the image data for each color.

Based on the output of the color extraction unit 81, the image plane position acquisition unit 83 acquires the incident positions of the light rays for each of RGB on the imaging surface 14a. The image plane position acquisition unit 83 identifies the imaging position of the light beam emitted from the object point O in each image data for each color.

The object point position calculator 84 calculates the three-dimensional position of the object point O of the test object S based on the imaging position of the light beam on the imaging surface 14a. That is, the object point position calculator 84 calculates the three-dimensional position of the object point O as information related to the test object S based on a plurality of imaging positions. The three-dimensional position of the object point O of the test object S is an example of information related to the test object S. FIG. The three-dimensional position of the object point O may be expressed as the three-dimensional position of a point on the object that is the object S to be inspected.

FIG. 15 is a diagram showing an example of the configuration of the camera 13 of the optical inspection device 4 according to this modification. FIG. 15 schematically shows an example of the ray path of the chief ray of the light emitted from the object point O of the test object S. As shown in FIG. As shown in FIG. 15 , the optical device 12 according to this modification includes an imaging optical system (imaging lens) 32 , first color filters 341 and second color filters 342 . The first color filter 341 and the second color filter 342 are arranged rotationally symmetrically with respect to the optical axis C of the imaging optical system 32 .

The imaging optical system 32 forms an image of the light rays emitted from the object point O on the object S to an image point on the imaging surface 14 a of the imaging unit 14 .

The first color filter 341 is arranged at a position (focal plane) of the image-side focal length f of the imaging optical system 32 . Therefore, the first color filter 341 is arranged at a position corresponding to the color filter 34 according to the first embodiment.

A second color filter 342 is arranged adjacent to the imaging optical system 32 . The second color filter 342 is arranged between the imaging optical system 32 and the first color filter 341 . The second color filter 342 may be arranged between the imaging optical system 32 and the observation window 64 of the container 16, that is, between the imaging optical system 32 and the test object S.

FIG. 16 is a schematic diagram showing an example of the first color filter 341 according to this modification. As shown in FIG. 16, the wavelength selection filter provided in the opening of the first color filter 341 has two concentric wavelength selection areas, a first area A1 and a second area A2.

The first area A1 is an area from radius ra to radius rb. A blue transmission filter that transmits blue (B) light is provided in the first area A1. That is, the first area A1 of the first color filter 341 is an area that transmits B light.

The second area A2 is an area with a radius of ra or less. A red transmission filter that transmits red (R) light is provided in the second area A2. That is, the second area A2 of the first color filter 341 is an area that transmits R light. The second area A2 is arranged on the optical axis C of the imaging optical system 32 .

FIG. 17 is a schematic diagram showing an example of the second color filter 342 according to this embodiment. As shown in FIG. 17, the wavelength selection member provided in the opening of the second color filter 342 has two concentric wavelength selection areas, a first area A1 and a second area A2.

The first area A1 is an area from radius ra to radius rb. A red transmission filter (fourth wavelength selection filter) that transmits red (R) light is provided in the first area A1. That is, the first area A1 of the second color filter 342 is an area that transmits R light.

The second area A2 is an area with radius r1 or less. A blue transmission filter (third wavelength selection filter) that transmits blue (B) light is provided in the second area A2. That is, the second area A2 of the second color filter 342 is an area that transmits B light. The second area A2 is arranged on the optical axis C of the imaging optical system 32 . The second area A2 is formed in a disk shape or an annular shape. Therefore, the first area A1 as a blue transmission filter is formed in an annular shape around the outer circumference of the second area A2 as a red transmission filter, and allows the B light from the test object S to pass therethrough.

Next, the operation of the optical inspection system 2 according to this modified example will be described.

For example, by illumination from the light source 18, a light beam including B light and R light is emitted from an arbitrary object point O on the object S to be inspected. These rays are reflected or scattered at object point O through viewing window 64 . Of the light rays reflected from an arbitrary object point O of the test object S and passing through the observation window 64, the light rays that have passed through the second color filter 342 and the first color filter 341 via the imaging optical system 32 are The light enters the imaging surface 14 a of the imaging unit 14 .

Consider a ray that is parallel to the optical axis C of the imaging optical system 32 when the ray that has been reflected from an arbitrary object point O of the test object S and has passed through the observation window 64 enters the imaging optical system 32. . As shown in FIG. 15, among these rays, the R light that has passed through the first region A1 of the second color filter 342 via the imaging optical system 32 is transferred to the second region A1 of the first color filter 341. It can pass through the area A2. On the other hand, the B light that has passed through the second area A2 of the second color filter 342 via the imaging optical system 32 does not have the wavelength component of the R light. A2 cannot be penetrated. In this way, the light beams (R light and B light) parallel to the optical axis C of the imaging optical system 32 pass through the first color filter 341 arranged at the image-side focal point of the imaging optical system 32. However, only the R light reaches the imaging surface 14 a of the imaging section 14 .

Next, let us consider light rays that are not parallel to the optical axis of the imaging optical system 32 when they enter the imaging optical system 32 . The R light that has passed through the first area A1 of the second color filter 342 via the imaging optical system 32 cannot pass through the first area A1 of the first color filter 341 because it does not have a blue wavelength component. . On the other hand, the B light that has passed through the second area A2 of the second color filter 342 via the imaging optical system 32 can pass through the first area A1 of the first color filter 341 . In this way, of the light rays (R light and B light) that are not parallel to the optical axis of the imaging optical system 32, only the B light reaches the imaging surface 14a of the imaging unit 14. FIG.

Thus, the optical device 12 according to this modification is a telecentric optical system having telecentricity on the object side with respect to R light. On the other hand, the optical device 12 according to this modification is a non-telecentric optical system that does not have telecentricity on the object side with respect to B light. In the optical device 12 according to this modified example, the optical axis of the telecentric optical system and the optical axis of the non-telecentric optical system match.

The imaging unit 14 simultaneously captures the R light that has passed through the optical device 12 as a telecentric optical system and the B light that has passed through the optical device 12 as a non-telecentric optical system, among the rays emitted from an arbitrary object point O. Take an image. The imaging unit 14 outputs imaging data obtained by imaging to the processing circuit 20 . A non-telecentric optical system may generally be expressed as a lens optical system.

Here, the operation of the processing circuit 20 will be described.

Also in this modification, the processing circuit 20 can output the contact angle based on the scattering angle θ. In this case, the processing circuit 20 operates as described in the first embodiment, and can calculate the contact angle from the scattering angle θ. That is, by measuring the relationship between the scattering angle θ and the contact angle before the experiment, the contact angle can be obtained by, for example, multiplying the scattering angle θ by an appropriate coefficient (not limited to a natural number). Therefore, the operation of the processing circuit 20 to output the contact angle based on the scattering angle θ will not be described here.

The processing circuit 20 according to this modification calculates the three-dimensional shape of the test object S based on the output of the imaging unit 14 . In the measurement process, a calculation process for calculating the three-dimensional position of the object point O is executed. The calculation processing includes the following color extraction processing, image plane position acquisition processing, and object point position calculation processing. A collection of object points O forms the shape of the object S to be inspected.

FIG. 18 is a flowchart showing an example of calculation processing according to this embodiment. The processing circuit 20 according to this modification operates according to the flowchart shown in FIG.

At step ST21, the processing circuit 20 executes color extraction processing. The processing circuit 20 as the color extraction unit 81 separates the colors of the captured image data and extracts image data for each color. In addition, although described as image data, it is not limited to data that can be displayed as an image, and light intensity for each pixel of each color of the imaging unit 14 may be extracted.

In step ST22, the processing circuit 20 executes image plane position acquisition processing. The processing circuit 20 as the image plane position acquisition unit 83 identifies the imaging position of the light beam for each color based on the image data for each color. The imaging position where the ray is imaged can also be expressed as the incident position of the ray on the imaging surface 14a. The processing circuit 20 as the image plane position acquisition unit 83 performs image processing such as edge enhancement on the image data, and specifies the imaging position corresponding to the object point O. FIG. At this time, for example, image processing such as pixel matching may be performed on the shape of the detected edge.

In step ST23, the processing circuit 20 executes object point position calculation processing. The R image, B image, and G image acquired by the imaging unit 14 according to the present embodiment are based on the arrangement of the wavelength selection filters 42, 44, and 46 of the imaging optical system 32 and the color filter 34 (position with respect to the color filter 34). relationship), each has information about an angle (inclination) corresponding to the scattering angle θ of the object S to be inspected. Therefore, the processing circuit 20 acquires information about the direction in which the object point O of the test object S exists for each color in each pixel of the imaging unit 14 .

The object point position calculation processing in step ST23 will be described more specifically.

Let (x, y, z) be the coordinates indicating the position of the object point O of the test object S in the three-dimensional space. Let (p, q) be the coordinates indicating the incident position of the R light emitted from the object point O and passed through the optical device 12 as a telecentric optical system, on the imaging surface 14a. Let (P, Q) be the coordinates indicating the incident position of the B light emitted from the object point O and passed through the optical device 12 as a non-telecentric optical system, on the imaging surface 14a. The incident position on the imaging surface 14a is the imaging position of the ray.

Here, the second area A2 of the first color filter 341 is an area through which R light is transmitted. A second area A2 of the second color filter 342 is an area through which B light is transmitted.

At this time, due to geometrical optics, the imaging position of the B light that has passed through the optical device 12 as a non-telecentric optical system is

となる。ただし、式（１）の右辺の第２項は、第２のカラーフィルタ３４２の第２の領域Ａ２の端部を通過する周辺光線（marginal ray）を意味する。

becomes. However, the second term on the right side of equation (1) means a marginal ray that passes through the edge of the second area A2 of the second color filter 342 .

On the other hand, due to geometrical optics, the imaging position of the R light that has passed through the optical device 12 as a telecentric optical system is

となる。ただし、式（２）の右辺の第２項は、第１のカラーフィルタ３４１の第２の領域Ａ２の端部を通過する周辺光線である。

becomes. However, the second term on the right side of equation (2) is the marginal ray that passes through the edge of the second area A2 of the first color filter 341 .

From the equations (1) and (2), the position of the object point O in the three-dimensional space can be obtained by using the imaging position of each ray as

と表すことができる。

It can be expressed as.

The processing circuit 20 according to this modified example can calculate the three-dimensional position of the object point O from the imaging data using Equation (3). Also, in the image plane position acquisition process, a plurality of imaging positions corresponding to a plurality of object points O on the object S are acquired for each color. A collection of object points O forms the shape of the object S to be inspected. Therefore, the optical inspection system 2 according to this modification can detect the three-dimensional position of the object point O of the test object S within the container body 62 . Therefore, the processing circuit 20 according to this modified example can calculate the three-dimensional shape of the test object S based on the imaging data obtained when the test object S is enclosed in the container body 62 .

As described above, according to the present modification, for example, even when the test object S is enclosed in the container main body 62, it is possible to inspect the state change such as the tilt (contact angle) of the test object S. In addition to the optical inspection device 4 and an optical inspection method for calculating the inclination (contact angle) of the test object S, an optical inspection method for the shape of the test object S can be provided.

Note that the first processor having the functions of the color extraction unit 81 and the scattering angle calculation unit 82 of the processing circuit 20 described in the first embodiment, the color extraction unit 81 of the processing circuit described in the modification, and the image plane The second processor having the functions of the position acquisition section 83 and the object point position calculation section 84 may be the same or different. That is, the first processor and the second processor may be formed as a single entity or may be formed separately.

(Second embodiment)
Next, a second embodiment will be described with reference to FIGS. 19 to 25. FIG. This embodiment is a modified example of the first embodiment including modified examples, and members that are the same as or have the same functions as the members described in the first embodiment are denoted by the same reference numerals as much as possible and will be described in detail. omitted.

As shown in FIG. 19, in this embodiment, the optical inspection device 4 and the container body 62 and observation window 64 of the container 16 have the same structures as those of the first embodiment, for example.

The heating section 72 of the container 16 is provided on the stage 66 directly below the observation window 64 . The heating unit 72 uses, for example, a halogen heater 72b. The heating unit 72 is attached to a stage 66 on which the test object S is placed.

In this embodiment, the container 16 has a gas supply 80 . The gas supply unit 80 includes a gas introduction valve 80a connected to the container body 62, and a gas cylinder 80b for supplying gas into the container body 62 via the gas introduction valve 80a. The gas introduction valve 80 a can introduce any gas type into the container body 62 . In this embodiment, it is assumed that the gas sealed in the gas cylinder 80b is nitrogen gas. Therefore, the gas supply unit 80 can fill the inside of the container body 62 with nitrogen gas through the gas supply unit 80 .

In this embodiment, the test object S has a Cu substrate S12, a solder material S22, and a surface mount component S32. It is assumed that the top surface S121 of the Cu substrate S12 is a horizontal plane, and the top surface S321 of the surface mount component S32 is a plane. Also, the outer diameter of the Cu substrate S12 is larger than the outer diameter of the upper surface S321 of the surface mount component S32.

The heating part 72 is arranged between the stage 66 and the Cu substrate S12. Therefore, when the heating portion 72 is heated, heat is transferred from the Cu substrate S12 to the solder material S22 to melt the solder material S22, and the surface mount component S32 and the Cu substrate S12 are joined via the solder material S22.

Here, the upper surface S321 of the surface mount component S32 and the upper surface S121 of the Cu substrate S12 are preferably parallel. However, the melted solder material S22 spreads unevenly between the Cu substrate S12 and the surface mount component S32, which may cause a slight tilt.

Using the optical inspection apparatus 4 according to the present embodiment, the inside of the container 16 is heated to melt and liquefy the solder material S22 between the Cu substrate S12 and the surface mount component S32. A test was conducted to measure the inclination angle of the upper surface S321 of the surface mount component S32.

As described above, the incident position of the scattered light component from the test object S on the imaging surface 14a and the wavelength that can pass through the color filter 34 change depending on the distance from the test object S. FIG. Therefore, the positional relationship (distance) between the subject S and the camera 13 is adjusted, and the relationship between the scattering angle θ and the tilt angle is adjusted. The relationship between the scattering angle θ and the tilt angle based on the positional relationship (distance) between the subject S and the camera 13 can be obtained in advance by experiment.

As described above, in the example of the present embodiment, for simplification of explanation, the object S and the camera 13 are arranged such that the scattering angle θ and the tilt angle correspond one-to-one (scattering angle θ=tilt angle). Adjust the positional relationship with Then, the relationship between the scattering angle θ and the tilt angle is stored in the memory 22 .

As shown in FIG. 19, a Cu substrate S12, a solder material S22, and a surface mount component S32 were placed on the stage 66 directly below the observation window 64 of the container 16. As shown in FIG. The Cu substrate S12 of the test object S is irradiated with illumination light from the light source 18 through the half mirror 36 and the observation window 64, and reflected light from the upper surface S121 of the Cu substrate S12 is emitted through the observation window 64 and the half mirror 36. obtained by the camera 13. That is, here, an image (RGB image) of the upper surface S121 of the Cu substrate S12 is acquired using the camera 13 through the observation window 64 supported by the container body 62, and an RGB image and/or a red light image is obtained. (R image), a blue light image (B image), and a green light image (G image) were displayed on the display 6 .

In this embodiment, the optical axis C of the optical device 12 is adjusted so that the light from the upper surface S121 of the Cu substrate S12 based on the illumination light from the light source 18 passes through the center of the color filter 34. FIG. That is, the upper surface S121 of the Cu substrate S12 is perpendicular to the optical axis C. As shown in FIG. Of the upper surface S121 of the Cu substrate S12, the specularly reflected light component (light portion) can be obtained as part of the R image. Among the B image and the G image, the regular reflection component from the upper surface S121 of the Cu substrate S12 is obtained as a black image.

After confirming the state that the upper surface S121 of the Cu substrate S12 is displayed as a bright portion in the R image by looking at the display 6, the inside of the container body 62 is evacuated. The operator waits until the degree of vacuum becomes 10 ⁻³ Pa or less, for example, when the pressure in the container body 62 is detected by the pressure detection unit 78 .

After the degree of vacuum in the container body 62 becomes 10 ⁻³ Pa or less as a result of detection by the pressure detection unit 78, the operation of the vacuum device 76 is stopped. An operator opens the gas introduction valve 80a and introduces the nitrogen gas in the gas cylinder 80b into the container main body 62 through the gas introduction valve 80a. The operator waits until the pressure inside the container main body 62 reaches approximately 0.5 Pa when the pressure detecting portion 78 detects the pressure inside the container main body 62 .

After the pressure in the container body 62 has reached about 0.5 Pa as a result of detection by the pressure detection unit 78, the operator supplies electric power to the halogen heater 72b of the heating unit 72 to heat the stage 66 and turn on the camera. 13, the optical inspection device 4 is used to start measuring the angle information of the inclination (inclination angle) of the upper surface S121 of the Cu substrate S12.

For example, a temperature detector (thermocouple) 74 measures the temperature inside the container body 62 . The operator confirms that the solder material S22 between the Cu substrate S12 and the surface mount component S32 has a melting point (here, 230° C.).

When the solder material S22 melts, the inclination angle of the upper surface S321 of the surface mount component S32 with respect to the upper surface S121 of the Cu substrate S12 may change. The angle of inclination of the upper surface S321 of the surface-mounted component S32 when the solder material S22 is further melted and the inclination of the upper surface S321 of the surface-mounted component S32 with respect to the upper surface S121 of the Cu substrate S12 stops This is the final inclination angle of the upper surface S321 of the mounting component S32.

For example, as a result of the melting of the solder material S22, the upper surface S321 of the surface mount component S32 may become parallel or substantially parallel to the upper surface S121 of the Cu substrate S12, as shown in FIG. At this time, the imaging unit 14 acquires the image of the upper surface S121 of the Cu substrate S12 and the upper surface S321 of the surface mount component S32 as regular reflection components. Therefore, as shown in FIG. 21, the display 6 of the optical inspection system 2 displays an image of the top surface S321 of the surface mount component S32 together with the top surface S121 of the Cu substrate S12 in the R image.

The memory 22 stores in advance the relationship between the channel from which the image is obtained and the scattering angle. Therefore, when it is recognized that the upper surface S321 of the surface mount component S32 is obtained as an R image, the processing circuit 20 reads from the memory 22 the tilt angle corresponding to the scattering angle in that image. The processing circuit 20 then outputs the tilt angle to the display 6 . In the case of the example shown in FIG. 20, since an R image is obtained, the processing circuit 20 outputs to the display 6 that the tilt angle (=scattering angle) is 0°.

For example, as a result of the melting of the solder material S22, the top surface S321 of the surface mount component S32 may tilt at an angle (tilt angle) α with respect to the top surface S121 of the Cu substrate S12, as shown in FIG. At this time, the imaging unit 14 acquires an image of the upper surface S121 of the Cu substrate S12 as a regular reflection component. Note that the imaging unit 14 may not be able to acquire any of the R image, the B image, and the G image depending on the inclination angle of the upper surface S321 of the surface mount component S32. In the case of the inclination angle α, as shown in FIG. 23, the imaging unit 14 acquires the image of the upper surface S321 of the surface mount component S32 as the G image.

The memory 22 stores in advance the relationship between the channel from which the image is obtained and the scattering angle. Therefore, when it is recognized that the upper surface S321 of the surface mount component S32 is obtained as a G image, the processing circuit 20 reads from the memory 22 the tilt angle corresponding to the scattering angle in that image. The processing circuit 20 then outputs the tilt angle to the display 6 . In the example shown in FIG. 22, since a G image is obtained, the processing circuit 20 outputs to the display 6 that the tilt angle (=scattering angle) is the angle α.

For example, as a result of the melting of the solder material S22, as shown in FIG. 24, the top surface S321 of the surface mount component S32 may tilt at an angle (tilt angle) β (<α) with respect to the top surface S121 of the Cu substrate S12. . At this time, the imaging unit 14 acquires an image of the upper surface S121 of the Cu substrate S12 as a regular reflection component. In the case of the tilt angle β, as shown in FIG. 25, the imaging unit 14 acquires the image of the upper surface S321 of the surface mount component S32 as the B image.

The memory 22 stores in advance the relationship between the channel from which the image is obtained and the scattering angle. Therefore, when it is recognized that the upper surface S321 of the surface mount component S32 is obtained as a B image, the processing circuit 20 reads from the memory 22 the tilt angle corresponding to the scattering angle in that image. The processing circuit 20 then outputs the tilt angle to the display 6 . In the case of the example shown in FIG. 24, the B image is obtained, so the processing circuit 20 outputs to the display 6 that the tilt angle (=scattering angle) is the angle β.

The angles of inclination α and β are usually in the range of 0° to several degrees, for example.

After melting the solder material S22, it is desirable that the top surface S321 of the surface mount component S32 is parallel to the top surface S121 of the Cu substrate S12. However, when the melted solder material S22 spreads unevenly, the upper surface S321 of the surface mount component S32 may slightly tilt with respect to the upper surface S121 of the Cu substrate S12. According to the present embodiment, the angle between the upper surface S321 of the surface mount component S32 and the upper surface S121 of the Cu substrate S12 before the solder material S22 is melted and after the solder material S22 is melted and the Cu substrate S12 and the surface mount component S32 are joined. By observing the change, it is possible to discover a poor connection between the surface mount component S32 and the Cu substrate S12.

According to this embodiment, even if the inside of the container body 62 is heated to several hundred degrees Celsius, the tilt of the test object S can be calculated without being affected by the temperature due to the heating. , and a method for calculating the inclination of the test object S can be provided.

According to the present embodiment, an optical inspection apparatus 4 capable of calculating the tilt of the test object S without being affected by the gas even in an appropriate gas atmosphere, and a method for calculating the tilt of the test object S are provided. can do.

Also in the present embodiment, the shape of the test object is detected using the method of detecting the shape of the test object according to the method described in the first embodiment or the method described in the modified example of the first embodiment. be able to. Therefore, according to this embodiment, even when the inside of the container body 62 is heated to several hundred degrees Celsius, the shape of the test object S can be detected without being affected by the temperature of the heating unit 72. An optical inspection device 4 and a method for detecting the shape of a test object can be provided.

Therefore, according to the present embodiment, for example, even when the test object is enclosed in the container main body 62, the optical inspection device 4 capable of inspecting the state change such as the inclination of the test object S, the test object An optical inspection method for the object S and an optical inspection method for the shape of the test object S can be provided.

According to at least one embodiment described above, an optical inspection apparatus capable of inspecting a change in state such as inclination of a test object even when the test object is enclosed in a container body, A method of optical inspection and a method of optical inspection of the shape of a test object can be provided.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 2... Optical inspection system, 4... Optical inspection apparatus, 12... Optical apparatus, 13... Camera, 14... Imaging unit, 14a... Imaging surface, 16... Container, 18... Light source, 32... Imaging optical system, 34... Color filter , 36... Half mirror 42, 44, 46... Wavelength selection filter 48... Light shielding part 62... Container main body 62a... Opening edge 64... Observation window 64a, 64b... Parallel surface 66... Stage 72... Heating part 74...Temperature detection part 76...Vacuum device 78...Pressure detection part

Claims (11)

a container having a container body in which a test object is accommodated, and an observation window having a pair of parallel surfaces separating the inside and the outside of the container body and allowing light from the test object to pass;
an imaging optical system that forms an image of the light beam from the test object that has passed through the observation window;
is arranged rotationally symmetrically with respect to the optical axis of the imaging optical system and provided on the focal plane of the imaging optical system,
A disk-shaped or toroidal first wavelength selector provided on the optical axis of the imaging optical system and passing through the imaging optical system and passing a ray of a first wavelength from the test object. a filter, and
A second filter, which is formed in an annular shape around the outer periphery of the first wavelength selection filter, passes through the imaging optical system, and passes a light beam of a second wavelength different from the first wavelength from the test object. a color filter having a wavelength selective filter of
The light beam of the first wavelength that is provided on the imaging plane of the imaging optical system and has passed through the first wavelength selection filter, and the light beam of the second wavelength that has passed through the second wavelength selection filter. An optical inspection device comprising: an imaging unit that captures an image of The container has a heating unit that heats the test object,
The container body and the observation window have heat resistance that suppresses deformation due to heat of the heating unit,
The optical inspection device according to claim 1. The first wavelength selection filter and the second wavelength selection filter of the color filter are formed to block a peak wavelength of light emitted from the heating unit when the heating unit is heated. The optical inspection device according to claim 2. outputting the contact angle of the liquid with respect to the base material at the boundary between the base material as the test object and the liquid as the test object on the base material based on the image captured by the imaging unit; 4. An optical inspection apparatus according to any one of claims 1 to 3, comprising one processor. the scattering angle of the light beam of the second wavelength with respect to the light beam of the first wavelength is set by the sizes of the radial regions of the first wavelength selection filter and the second wavelength selection filter;
the scattering angle corresponds to the contact angle;
The optical inspection device according to claim 4. Based on the image data captured by the imaging unit, a first image of light having the first wavelength passing through the first wavelength selection filter and the second image passing through the second wavelength selection filter a second processor for generating a second image with light of the wavelength;
The second processor identifies imaging positions of points on the test object in each of the first image and the second image, and provides information about the test object based on the plurality of imaging positions. 6. The optical inspection apparatus according to any one of claims 1 to 5, wherein the three-dimensional position of the point on the object is calculated as . arranged rotationally symmetrically with respect to the optical axis between the imaging optical system and the color filter or between the imaging optical system and the observation window;
a disc-shaped or annular third wavelength selection filter provided on the optical axis of the imaging optical system and allowing the light beam of the second wavelength from the test object to pass therethrough;
a second color filter having a fourth wavelength selection filter that is formed in an annular shape around the outer periphery of the third wavelength selection filter and that allows the light beam of the second wavelength from the test object to pass therethrough; Item 7. The optical inspection device according to item 6. 8. The optical inspection apparatus according to any one of claims 1 to 7, wherein a vacuum device is connected to said container body. 9. The optical inspection apparatus according to any one of claims 1 to 8, wherein a gas introduction valve capable of introducing any gas species is connected to said container body. An optical inspection method for inspecting a boundary between the base material and the liquid of the test object using the optical inspection apparatus according to claim 4 or 5,
imaging the first wavelength ray that has passed through the first wavelength selection filter and the second wavelength ray that has passed through the second wavelength selection filter in the imaging unit;
outputting the contact angle at the boundary between the substrate and the liquid based on the image captured by the imaging unit;
An optical inspection method for the test object. An optical inspection method for inspecting the shape of the test object using the optical inspection apparatus according to claim 6 or 7,
Based on the image data captured by the imaging unit, the first image by the light beam of the first wavelength that has passed through the first wavelength selection filter and the light beam that has passed through the second wavelength selection filter producing said second image with light of a second wavelength;
Identifying the imaging positions of points on the test object in each of the first image and the second image;
calculating a three-dimensional position of a point on the test object as information related to the test object based on the plurality of imaging positions;
A method for optically inspecting the shape of the test object.

Images