3D shape inspection device and 3D shape inspection method

Abstract

A three-dimensional shape inspection device according to a disclosed embodiment includes a light source and a spatial light modulator configured to modulate light received from the light source, and a light irradiation unit configured to irradiate a plurality of light beams having a plurality of foci downward onto the surface of a measurement object; an optical system configured to refract each of the modulated light beams with different refractive indices according to a plurality of wavelengths using chromatic aberration, thereby forming an upward and downward measurement section in which the refracted light according to wavelength is focused; an optical splitter configured to transmit a portion of the light reflected by the measurement object and to reflect another portion of the light reflected by the measurement object; a first detection unit that detects information regarding the wavelength of the light transmitted through the optical splitter; and a second detection unit that detects information regarding the wavelength of the light reflected from the optical splitter, and the filter detection unit, which is either the first detection unit or the second detection unit, is equipped with a filter unit that blocks light of a specific wavelength or above and is configured to detect information regarding light of a wavelength below the specific wavelength.

Description

[Technical Field]

[0001] The present disclosure relates to a three-dimensional shape inspection device and a three-dimensional shape inspection method. [Background technology]

[0002] Confocal microscopy (or confocal laser scanning microscopy, CLSM) is a type of microscope that uses a pinhole to remove out-of-focus light, eliminating interference from light outside the focal area and achieving high resolution and accuracy. It is used in fields such as life science, semiconductors, and materials science.

[0003] Among confocal microscopes, chromatic confocal microscopy is known for using chromatic aberration to perform 3D inspection of an object. Chromatic confocal microscopy refracts white light emitted from a light source at different refractive indices for different wavelengths and irradiates the refracted light onto the surface of the object. The refracted light is focused on the surface of the object and reflected, which is then transmitted through a pinhole. The wavelength of the transmitted light is detected using a spectrometer. Chromatic confocal microscopes perform 3D inspections by storing a table of focal length information for the optical system corresponding to the wavelength of the focused light and measuring the height of the object based on the wavelength of the detected light. Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional chromatic confocal microscopes perform 3D inspection by irradiating light emitted from a light source at only one point on the surface of an object to be measured and detecting the reflected light, and are limited to a point scan method or a very short line scan method, resulting in a very slow inspection speed. The embodiments of the present disclosure solve the problems of the conventional technology.

[0005] In addition, conventional chromatic confocal microscopes have a problem in that, when a measurement object includes a transparent body, information about the refractive index of the transparent body must be obtained in advance in order to be able to inspect the measurement object. Furthermore, there is a problem in that the possibility of inspection varies depending on the shape of the test piece, since inspection may be impossible depending on the shape of the test piece. The embodiments of the present disclosure solve the problems of the conventional technology. [Means for solving the problem]

[0006] One aspect of the present disclosure provides an embodiment of a three-dimensional shape inspection device. The three-dimensional shape inspection device according to a representative embodiment includes: a light source; a spatial light modulator configured to modulate light received from the light source; a light irradiation unit configured to irradiate a plurality of light beams having a plurality of foci downward onto a surface of a measurement object; an optical system configured to refract each of the modulated light beams with different refractive indices according to a plurality of wavelengths using chromatic aberration, thereby forming an up-down measurement zone in which the refracted light beams according to wavelength are focused; an optical splitter configured to transmit a portion of the light reflected by the measurement object and reflect another portion of the light reflected by the measurement object; a first detection unit configured to detect information about the wavelength of the light transmitted through the optical splitter; and a second detection unit configured to detect information about the wavelength of the light reflected from the optical splitter, wherein the filter detection unit, which is either the first detection unit or the second detection unit, includes a filter unit that blocks light of a specific wavelength or above and is configured to detect information about light of a wavelength below the specific wavelength.

[0007] In one embodiment, the three-dimensional shape inspection device may further include a control unit that measures the height of the base of the measurement object and the height of a transparent body placed on the base based on the information detected by the first detection unit and the information detected by the second detection unit.

[0008] In one embodiment, the filter detector may be configured to detect light intensity information.

[0009] In one embodiment, the 3D shape inspection device may further include a focus adjustment unit configured to change the measurement section by vertically changing the position where the refracted light for each wavelength is focused, and a control unit configured to control the focus adjustment unit to change the measurement section when it is determined that the light intensity information is equal to or lower than a predetermined first specific intensity.

[0010] In one embodiment, when the control unit determines that the light intensity information is equal to or lower than a predetermined first specific intensity, the control unit may control the focus adjustment unit to change the measurement section so that light with a shorter wavelength is reflected by the measurement object.

[0011] In one embodiment, the 3D shape inspection device may further include a focus adjustment unit configured to change the measurement section by vertically changing the position where the refracted light for each wavelength is focused, and a control unit configured to control the focus adjustment unit to change the measurement section when it is determined that the light intensity information is equal to or greater than a predetermined second specific intensity.

[0012] In one embodiment, when the light intensity information is determined to be equal to or greater than a predetermined second specific intensity, the control unit may control the focus adjustment unit to change the measurement section so that light with a longer wavelength is reflected by the measurement object.

[0013] In one embodiment, the three-dimensional shape inspection device may further include a focus adjustment unit configured to change the measurement section by vertically changing the position where the refracted light for each wavelength is focused, and a control unit that controls the focus adjustment unit to change the measurement section when the light intensity information satisfies a predetermined criterion, and the first detection unit and the second detection unit may be configured to again detect information regarding the wavelength of the light after the measurement section has been changed.

[0014] In one embodiment, the control unit may be configured to (i) acquire first information detected by a no-filter detection unit that is not the filter detection unit, of the first detection unit and the second detection unit, in a first state before the measurement section is changed, and acquire second information detected by the filter detection unit; (ii) acquire third information detected by the no-filter detection unit and fourth information detected by the filter detection unit in a second state after the measurement section is changed; and (iii) measure the height of the base of the object to be measured and the height of a transparent body placed on the base based on the first information, the second information, the third information, and the fourth information.

[0015] In one embodiment, when a value proportional to an average value of the distance from the optical system to a position where the light refracted for each wavelength is focused is defined as a working distance, the control unit may be configured to measure the refractive index of the transparent body based on the working distance in the first state, the working distance in the second state, the first information, and the third information.

[0016] In one embodiment, the optical system has a unique focus shift value for each wavelength due to chromatic aberration, and when a value proportional to an average value of a distance from the optical system to a position where light refracted for each wavelength is focused is defined as a working distance, the control unit may be configured to measure a refractive index that is a value obtained by subtracting the working distance in the second state from the working distance in the first state, divided by a value obtained by subtracting the first focus shift value corresponding to the first information from a third focus shift value corresponding to the third information.

[0017] In one embodiment, the control unit may be configured to measure the height of a base of the object to be measured and the height of a transparent body placed on the base based on the first information, the second information, the third information, the fourth information, and the refractive index.

[0018] In one embodiment, the focus adjustment unit may include a variable lens configured to change the measurement range based on an applied current, and may be configured such that the larger the applied current, the larger the value obtained by subtracting the working distance in the second state from the working distance in the first state.

[0019] In one embodiment, the filter detector may be the second detector.

[0020] In one embodiment, the spatial light modulator may include a plurality of digital micromirror devices arranged in an array and configured to reflect and thereby modulate light received from the light source.

[0021] In one embodiment, the first detection unit and the second detection unit may be configured to detect color information of light refracted according to wavelength and focused and reflected at a position corresponding to the height of a base of the measurement object or the height of a transparent body placed on the base.

[0022] In one embodiment, the light irradiation unit may be configured to irradiate the plurality of lights having a plurality of focal points in a horizontal direction perpendicular to a vertical direction downward onto the surface of the measurement object.

[0023] Another aspect of the present disclosure provides an embodiment of a method for inspecting a three-dimensional shape. The method for inspecting a three-dimensional shape according to a representative embodiment includes: a light modulation step of modulating light received from a light source to irradiate a surface of a measurement object with a plurality of light beams having a plurality of foci; a light irradiation step of irradiating the modulated light beams downward to form an up-down measurement section in which the refracted light beams according to wavelengths are focused by refracting each of the modulated light beams with different refractive indices according to a plurality of wavelengths using chromatic aberration; a light path forming step of transmitting a portion of the light beam reflected by the measurement object and reflecting another portion of the light beam reflected by the measurement object using an optical splitter; a first detection step of detecting information about the wavelength of the transmitted light in the light path forming step; and a second detection step of detecting information about the wavelength of the reflected light in the light path forming step, wherein either one of the first detection step and the second detection step includes a filter detection step of blocking light having a wavelength equal to or greater than a specific wavelength and detecting information about light having a wavelength less than the specific wavelength.

[0024] In one embodiment, the filter detection step may be configured to detect light intensity information, and the 3D shape inspection method may further include a focus adjustment step of changing the measurement section by vertically changing the position where the refracted light for each wavelength is focused when it is determined that the light intensity information is equal to or less than a predetermined first specific intensity or equal to or more than a predetermined second specific intensity.

[0025] In one embodiment, the filter detection step is configured to detect light intensity information, and the 3D shape inspection method may further include a focus adjustment step of changing the measurement range by vertically changing a position where the refracted light for each wavelength is focused when the light intensity information satisfies a predetermined criterion, and the first detection step and the second detection step may be performed again with the measurement range changed. [Effects of the Invention]

[0026] According to an embodiment of the present disclosure, it is possible to inspect a large area of ​​an object in 3D at a faster speed using a spatial light modulator and an image sensor that detects color information of light.

[0027] According to the embodiment of the present disclosure, even when the measurement object includes a transparent body, it is possible to inspect the measurement object without information about the refractive index of the transparent body.

[0028] According to an embodiment of the present disclosure, even when the measurement object includes a transparent body, it is possible to inspect the measurement object regardless of the shape of the measurement object. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 10 is a schematic diagram showing a driving method of a three-dimensional shape inspection device according to a comparative example of the present disclosure. [Figure 2] 1. FIG. 4 is a schematic diagram illustrating a problem with the three-dimensional shape inspection device according to the comparative example of FIG. 1 when a transparent body is placed on the base of the object to be measured. [Figure 3] 3 is a graph showing the wavelength and luminous intensity of light detected from a spectroscope of a three-dimensional shape inspection device according to a comparative example in the situation of FIG. 2. [Figure 4] 10A and 10B are schematic diagrams illustrating problems that occur in an inspection situation with a three-dimensional shape inspection device according to a comparative example, depending on the shapes of the base and the transparent body. [Figure 5] 1 is an overall perspective view of a three-dimensional shape inspection device according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a cross-sectional view taken along the line A1-A1′ shown in FIG. [Figure 7] FIG. 1 is a schematic diagram illustrating a digital micromirror device used in one embodiment of the present disclosure. [Figure 8] FIG. 1 is a schematic diagram illustrating a charge-coupled device (CCD) used in one embodiment of the present disclosure. [Figure 9] FIG. 2 is a schematic diagram illustrating a process in which a three-charge coupled device according to an embodiment of the present disclosure acquires RGB information of light. [Figure 10]FIG. 10 is a conceptual diagram showing a process of converting the RGB information acquired in FIG. 9 into an HSV coordinate system. [Figure 11] 1 is a schematic diagram illustrating an operation of a three-dimensional shape inspection device according to an embodiment of the present disclosure. [Figure 12] 12 is a graph illustrating an operation method of a filter unit that blocks light having a wavelength equal to or greater than a specific wavelength in FIG. 11. [Figure 13] 1 is a schematic diagram showing light refracted by an optical system according to wavelength and focused and reflected at a position corresponding to the height of the base of the object to be measured or the height of a transparent body placed on the base. [Figure 14] 10 is a graph showing a situation in which the intensity information of light detected by the filter detection unit is determined to be equal to or lower than a predetermined first specific intensity. [Figure 15] 10 is a graph showing a situation in which the intensity information of light detected by the filter detection unit is determined to be equal to or greater than a predetermined second specific intensity. [Figure 16] 10 is a graph showing a situation in which light intensity information detected by a filter detection unit satisfies a predetermined standard. [Figure 17] 1 is a schematic diagram showing how a three-dimensional shape inspection device according to an embodiment of the present disclosure can perform inspection regardless of the shapes of a base and a transparent body. [Figure 18] 1 is a schematic diagram illustrating a method for measuring the height of a base of a measurement object and the height of a transparent body placed on the base in a three-dimensional shape inspection device according to an embodiment of the present disclosure. [Figure 19] 1 is a graph showing a characteristic focus shift value for each wavelength of an optical system according to an embodiment of the present disclosure. [Figure 20] 1 is a flowchart showing the flow of an embodiment of a three-dimensional shape inspection method according to the present disclosure. [Figure 21] 1 is a flowchart showing the flow of an embodiment of a three-dimensional shape inspection method according to the present disclosure when a transparent body is included in the measurement object. DETAILED DESCRIPTION OF THE INVENTION

[0030] The examples of the present disclosure are provided for the purpose of explaining the technical concept of the present disclosure, and the scope of the rights of the present disclosure is not limited to the examples presented below or the specific descriptions of these examples.

[0031] Unless otherwise specified, all technical and scientific terms used in this disclosure have the meanings commonly understood by those of ordinary skill in the art to which this disclosure belongs. All terms used in this disclosure have been selected for the purpose of more clearly describing this disclosure, and are not selected to limit the scope of rights related to this disclosure.

[0032] As used in this disclosure, terms such as "including," "comprising," "having," and the like should be understood as open-ended terms that include the possibility of including other embodiments, unless otherwise specified in the phrase or sentence in which the term is included.

[0033] In this disclosure, the singular terms "a," "an," and "the" may include the plural meaning unless otherwise specified, and this also applies to the singular terms recited in the claims.

[0034] The terms "first", "second", etc. used in this disclosure are used to distinguish between multiple elements, and do not limit the order or importance of the elements.

[0035] The term "module" as used in this disclosure refers to software or hardware components such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, a "module" is not limited to hardware and software, and may be configured to reside on an addressable storage medium or to implement one or more processors. Thus, by way of example, a "module" includes components such as software components, object-oriented software components, class components, and task components, as well as processors, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. Additionally, the functionality provided within components and "modules" may be combined into fewer components and "modules" or further separated into additional components and "modules."

[0036] As used in this document, the phrase "based on" is used to describe one or more factors that influence the decision, act of judgment, or behavior described in the phrase or sentence in which it appears, and does not exclude additional factors that influence that decision, act of judgment, or behavior.

[0037] In this disclosure, when a component is referred to as being "coupled" or "connected" to another component, it should be understood that the component is directly coupled or connected to the other component, or is coupled or connected through yet another component.

[0038] Directional terms such as "below" and "down" used in this disclosure refer to the direction in which the measurement object is positioned relative to the 3D shape inspection device in the attached drawings, and directional terms such as "up" and "above" refer to the opposite direction. However, this is merely for the purpose of explanation to make this disclosure clearer, and the definition of each direction may change depending on the reference point.

[0039] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the accompanying drawings, identical or corresponding components are designated by the same reference numerals. Furthermore, in the following description of the embodiments, duplicated descriptions of identical or corresponding components may be omitted. However, omission of a description of a component does not mean that the component is not included in any of the embodiments.

[0040] FIG. 1 is a schematic diagram showing a driving method of a three-dimensional shape inspection device according to a comparative example of the present disclosure.

[0041] The operation of the three-dimensional shape inspection device 50 according to the comparative example will be described below with reference to FIG.

[0042] The three-dimensional shape inspection apparatus 50 can irradiate light onto the surface of the measurement object 20 by transmitting light emitted from a light source 52 through a beam splitter 54. The light source 52 may be configured to emit light having multiple wavelengths. The measurement object 20 may include various inspected objects, such as cells, metal and non-metal materials, and semiconductor substrates used in fields such as life science, semiconductors, and materials science. The measurement object 20 may also include a transparent body or other material, and may include a mirror surface (C4 bump, μ bump, die, etc.) of a semiconductor or the like.

[0043] The light transmitted through the beam splitter 54 may be refracted by the optical system 56. The optical system 56 may be configured to refract incident light at different refractive indices according to wavelengths using chromatic aberration. The optical system 56 may be configured to focus light using chromatic aberration so that light with longer wavelengths is focused farther from the optical system 56 and light with shorter wavelengths is focused closer to the optical system 56. For example, referring to FIG. 1 , the manner in which light having multiple wavelengths is refracted by the optical system 56 at different refractive indices is shown, with light having the shortest wavelength λ1 of the multiple wavelengths being focused closest to the optical system 56 and light having the longest wavelength λn of the multiple wavelengths being focused farthest from the optical system 56. Among the light refracted according to wavelength, there may be light having a height-corresponding wavelength λm that is focused at a position corresponding to the height on the surface of the measurement object 20. The height-corresponding wavelength λm may have a value between the shortest wavelength λ1 and the longest wavelength λn.

[0044] The light refracted according to the plurality of wavelengths may be configured to be reflected on the surface of the measurement object 20 and reflected from the beam splitter 54. The beam splitter 54 can reflect the light having the plurality of wavelengths reflected on the surface of the measurement object 20 toward the pinhole 58. The beam splitter 54, the optical system 56, and the pinhole 58 may be configured to transmit only light having a height-corresponding wavelength λ m, which is focused and reflected at a position corresponding to the height on the surface of the measurement object 20, among the light having the plurality of wavelengths. A spectrometer 60 may be formed on the light path passing through the pinhole 58. The spectrometer 60 may be configured to detect the light as a spectrum according to wavelength and to detect intensity information according to the wavelength of the light.

[0045] The three-dimensional shape inspection device 50 may be configured to measure the height of the measurement object 20 by detecting wavelength components of light focused on the surface of the measurement object 20 using a spectrometer 60. 3D inspection may be performed to inspect the three-dimensional shape of the measurement object 20 by moving the three-dimensional shape inspection device 50 or the measurement object 20 horizontally during inspection. The three-dimensional shape inspection device 50 of the comparative example is limited to a very slow inspection speed because it is only capable of a point scan method or a very small line scan method in which light emitted from a light source 52 irradiates only one point on the surface of the measurement object to perform 3D inspection. The inspection speed of the point scan method of the three-dimensional shape inspection device 50 of the comparative example is less than 1 mm2.

[0046] Fig. 2 is a schematic diagram illustrating the problem of the three-dimensional shape inspection device according to the comparative example of Fig. 1 when a transparent body is placed on the base of the measurement object. Fig. 3 is a graph showing the wavelength and luminous intensity of light detected from the spectroscope of the three-dimensional shape inspection device according to the comparative example of Fig. 2.

[0047] Referring to FIG. 2, the measurement object 20 may include a base 22 and a transparent body 24. The transparent body 24 may be disposed on the base 22. The transparent body 24 is a medium through which light passes as it travels through the medium. The refractive index n of the transparent body 24 may be different from that of the space through which the light travels before passing through the transparent body 24, which is disposed in a space. Since the refractive index n of the transparent body 24 differs from that of other spaces, light incident on the transparent body 24 is refracted and passes through the transparent body 24.

[0048] As shown in FIG. 3, the three-dimensional shape inspection device 50 measures the height of the object 20 by detecting the wavelength components of light focused on the surface of the object 20. When a transparent body 24 is placed on the base 22 of the object 20, the light focused and reflected on the surface of the object 20 may contain two wavelength components. For example, there may be a wavelength λ1 component of the light focused and reflected on the surface of the transparent body 24 of the object 20, and a wavelength λ2 component of the light focused and reflected on the surface of the base 22 of the object 20. If the wavelength λ1 component of the light focused and reflected on the surface of the transparent body 24 of the object 20 is detected, the distance h0 from the optical system to the surface of the transparent body can be measured. However, if the wavelength λ2 component of the light focused and reflected on the surface of the base 22 of the object 20 is detected, the distance h0 + h1, which corresponds to the wavelength λ2 of the light, can be measured. The distance (h0+h1) measured based on the wavelength λ2 of light reflected and detected on the surface of the base 22 differs from the distance (h0+h1+h2) from the optical system to the actual location of the base, which can reduce the inspection accuracy of the 3D shape inspection device. Therefore, without information about the refractive index n of the transparent body, it is impossible to correct the measured distance (h0+h1) to the distance (h0+h1+h2) from the optical system to the actual location of the base.

[0049] FIG. 4 is a schematic diagram for explaining problems that occur in the three-dimensional shape inspection device according to the comparative example due to the shapes of the base and the transparent body.

[0050] 1 and 4, it is shown that light having multiple wavelengths is refracted by the optical system 56 with different refractive indices, and that light having the shortest wavelength λ1 of the multiple wavelengths is focused at a location closest to the optical system 56, and light having the longest wavelength λn of the multiple wavelengths is focused at a location farthest from the optical system 56. Furthermore, the multiple wavelengths may include any wavelengths λp and λq having values ​​between the shortest wavelength λ1 and the longest wavelength λn.

[0051] As shown in Figure 4(a), among the light refracted by the optical system according to wavelength, there is light that is focused at a position corresponding to the height of the base 22 or the height of the transparent body 24, and the wavelengths of the focused light have wavelengths λp and λq values ​​that fall between the shortest wavelength λ1 and the longest wavelength λn. Therefore, in a situation like Figure 4(a), inspection is possible based on the height corresponding to the detected wavelengths λp and λq. However, in situations like Figure 4(b) and (c), inspection may be impossible depending on the shape of the test piece.

[0052] As shown in Figure 4(b), the measurement object 20 may be a test piece having a very thick base 22. Because the base 22 is very thick, among the light refracted by the optical system according to wavelength, only light that is focused at a position corresponding to the height of the base 22 may exist, and no light may exist that is focused at a position corresponding to the height of the transparent body 24. Therefore, in a situation like Figure 4(b), it may be impossible to inspect the transparent body 24, and therefore it may be impossible to inspect the measurement object 20.

[0053] As shown in Figure 4(c), the measurement object 20 may be a test piece having a very thick transparent body 24. Because the transparent body 24 is very thick, among the light refracted by the optical system according to wavelength, only light that is focused at a position corresponding to the height of the transparent body 24 may exist, and no light may exist that is focused at a position corresponding to the height of the base 22. Therefore, in a situation like Figure 4(c), it may be impossible to inspect the base 22, and therefore it may be impossible to inspect the measurement object 20.

[0054] In contrast, a 3D shape inspection device and a 3D shape inspection method according to an embodiment of the present disclosure, which will be described below with reference to Figures 5 to 21, have the advantage of enabling high-speed, large-area 3D inspection of a measurement object using a spatial light modulator and an image sensor that detects color information of light. Furthermore, the present disclosure provides a 3D shape inspection device and a 3D shape inspection method that are capable of inspecting a measurement object that includes a transparent body even when the refractive index of the transparent body is unknown, and that are capable of inspection regardless of the shape of the test piece of the measurement object.

[0055] Fig. 5 is an overall perspective view of a three-dimensional shape inspection device according to an embodiment of the present disclosure, and Fig. 6 is a cross-sectional view taken along line A1-A1' shown in Fig. 5.

[0056] 5 and 6, the three-dimensional shape inspection apparatus 10 may be configured to inspect the three-dimensional shape of the measurement object 20. The three-dimensional shape inspection apparatus 10 may be configured to inspect the shape of the measurement object 20 by irradiating light onto the measurement object 20 and detecting information about the reflected light. The three-dimensional shape of the measurement object 20 can be inspected by detecting the positions and heights of multiple surfaces of the measurement object 20 while moving the three-dimensional shape inspection apparatus 10 or the measurement object 20. For convenience of explanation, FIG. 5 shows the three-dimensional shape inspection apparatus 10 and the measurement object 20 positioned in one location, but the present disclosure is not limited thereto, and the three-dimensional shape inspection apparatus 10 and the measurement object 20 may be moved vertically or horizontally during inspection.

[0057] The three-dimensional shape inspection device 10 may include a light irradiation unit 100, an optical system, a light splitter 230, and an image sensor 400.

[0058] The light irradiating unit 100 may be configured to irradiate light onto the surface of the measurement object 20. The light irradiating unit 100 may be configured to irradiate light in a downward direction where the measurement object 20 is located.

[0059] The light irradiation unit 100 may include a light source (not shown) and a spatial light modulator 110. The light source may be a white light source having multiple wavelengths. The light source may include any one of an LED, a halogen lamp, or a xenon lamp. The light source may include a sunlike LED. The present disclosure is not limited thereto, and any light source capable of emitting light having multiple wavelengths may be used in the present disclosure.

[0060] The light irradiator 100 may include a light irradiator case 150 that introduces light L from the light source into the three-dimensional shape inspection device 10. The light irradiator case 150 may have a space formed therein and be configured to receive light L from the light source. The internal space of the light irradiator case 150 may be a stop on the path along which light L from the light source is irradiated to the measurement object 20. The light irradiator case 150 may have a hole formed therein and include a light receiver 152 that protrudes to the outside. The light L from the light source may be received inside the three-dimensional shape inspection device 10 through the light receiver 152.

[0061] The spatial light modulator 110 may be configured to modulate the light L received from the light source. The spatial light modulator 110 may include any device that can change the amplitude or phase information of incident light depending on the position. The spatial light modulator 110 may be a device that controls the spatial distribution of light, thereby forming a light image in three-dimensional space.

[0062] The spatial light modulator 110 may be configured to modulate light received from the light source so that the light has multiple focal points. The light irradiation unit 100 may be configured to irradiate a plurality of light beams having multiple focal points onto the surface of the measurement object 20. Although FIGS. 5 and 6 show that a single light beam having a single focal point is irradiated onto the surface of the measurement object 20, this is for convenience of explanation, and a plurality of digital micromirror devices (DMDs), which are an example of a spatial light modulator described below in conjunction with FIG. 7, may be used to irradiate a plurality of light beams having multiple focal points onto the surface of the measurement object 20.

[0063] The optical system can refract light according to multiple wavelengths using chromatic aberration. The optical system can refract light according to multiple wavelengths with different refractive indices. The optical system can refract each light modulated by the spatial light modulator 110. The optical system can be configured to refract light having multiple wavelengths with different refractive indices to form a measurement zone in which the refracted light according to wavelength is focused. The measurement zone can be formed in the vertical direction. Although FIGS. 5 and 6 show that a single light having a single focus is irradiated onto the surface of the measurement object 20, as shown in FIG. 1, the modulated light can form a vertical measurement zone by using the optical system to refract light L received from a light source with different refractive indices according to multiple wavelengths.

[0064] The optical system may include multiple lenses 211, 212, 213, 214, 215, and 241. The lenses may include any optical device that focuses or diverges light by refracting the light it receives. The lenses may include a variable lens 241 whose curvature is adjustable. The variable lens 241 will be described later along with the focus adjustment unit 240.

[0065] The three-dimensional shape inspection apparatus 10 may include a reflecting unit 220 that reflects light and changes the travel path of the light. The reflecting unit 220 may include an optical device configured to reflect the received light so that the light is transmitted to another path.

[0066] The three-dimensional shape inspection device 10 may include an optical splitter 230 that reflects a portion of the light and transmits the other portion of the light, thereby splitting the travel path of the light into two paths. The optical splitter 230 may be configured to transmit a portion of the light reflected by the measurement object. The optical splitter 230 may be configured to reflect the other portion of the light reflected by the measurement object.

[0067] The image sensor 400 can detect color information of light. The image sensor 400 can detect light reflected by the measurement object 20. The image sensor 400 can detect light that is focused and reflected at a position corresponding to a height on the surface of the measurement object 20, among light that is refracted according to wavelength and reflected by the measurement object 20. The height on the surface may be the height of the base 22 or the transparent body 24 of the measurement object 20. The image sensor 400 may be configured to detect color information of a plurality of light beams that are focused and reflected on the surface of the measurement object 20.

[0068] In one embodiment, the three-dimensional shape inspection apparatus 10 may include a control unit that measures the height of the surface of the measurement object 20. The control unit may include a computer that stores programs and / or information. The control unit may be configured to measure the height of the measurement object 20 based on color information detected by the image sensor 400. The height of the measurement object 20 from which the multiple lights are reflected can be measured based on the color information of the multiple lights detected by the image sensor 400. The image sensor 400 can measure each height on the surface of the measurement object 20 from which the multiple lights are reflected. The image sensor 400 of the three-dimensional shape inspection apparatus 10 of the present disclosure can measure the heights on multiple surfaces of the measurement object 20 at once, thereby enabling high-speed large-area inspection of the measurement object.

[0069] 7 is a schematic diagram showing a digital micromirror device used in an embodiment of the present disclosure. With reference to FIG. 7, a digital micromirror device (hereinafter referred to as DMD) will be described as an example of a spatial light modulator 110 according to an embodiment of the present disclosure.

[0070] The spatial light modulator 110 may include a digital micromirror device (DMD) using digital light processing (DLP) technology. The digital micromirror device (DMD) may include multiple DMDs arranged in an array. The digital micromirror device (DMD) may be a micro-sized mirror fabricated using a micro-electromechanical system (MEMS). That is, each of the multiple digital micromirror devices (DMDs) can function as a pixel. The digital micromirror devices (DMDs) in FIG. 6 form an array with 18 rows and 19 columns, but the numbers of rows and columns that make up the array are exemplary, and any other number of rows and columns may be used.

[0071] The DMD may have electrodes at its bottom to receive electrical signals from the outside and a reflecting mirror at its top to reflect light. An electrical signal is applied to the electrodes at the bottom of the DMD to adjust the angle of the reflecting mirror, so that the reflected light is either reflected by an external projection lens (not shown) and emitted, or reflected by a light-absorbing plate (not shown) and absorbed instead of being emitted. Adjusting the electrodes at the bottom of the DMD can control the on / off state of the light from each DMD. The spatial light modulator 110 can adjust each pixel of the DMD to an on / off state, so that it can modulate light L received from a light source into light having a desired shape and form. In FIG. 6, the digital micromirror devices in 4n+1 rows and 4n+1 columns of the array are shown to be in the on state (n is an integer greater than or equal to 0), but the present disclosure is not limited to this, and the digital micromirror devices of individual array elements can be arbitrarily adjusted to the on / off state.

[0072] 5 to 7, the light irradiation unit 100 may be configured to irradiate a plurality of lights downward onto the surface of the measurement object 20 in a horizontal direction perpendicular to the up-down direction. Each of the plurality of digital micromirror devices (DMDs) may be adjusted to an on / off state, and light reflected by the on-state digital micromirror device (DMD) may be emitted toward the measurement object 20. Therefore, the plurality of lights emitted and modulated from each of the plurality of digital micromirror devices (DMDs) may be configured to have a plurality of focal points. The three-dimensional shape inspection apparatus 10 according to an embodiment of the present disclosure may be configured to irradiate a plurality of lights having a plurality of focal points onto the surface of the measurement object 20.

[0073] Fig. 8 is a schematic diagram showing a charge-coupled device (CCD) used in one embodiment of the present disclosure. Fig. 9 is a schematic diagram showing a process in which a three-charge-coupled device according to one embodiment of the present disclosure acquires RGB information of light. Fig. 10 is a conceptual diagram showing a process in which the RGB information acquired in Fig. 8 is converted into an HSV coordinate system.

[0074] In one embodiment referring to FIG. 8, the image sensor may include a charge coupled device (hereinafter referred to as a CCD). A charge coupled device (CCD) refers to a sensor that converts light into electric charges to obtain light information. A charge coupled device (CCD) is configured with a pixel-shaped chip and has a photodiode inside that generates electrons according to the amount of photons. Therefore, light intensity information can be obtained by measuring and reconstructing the amount of electrons or current.

[0075] The charge-coupled device (CCD) may include a plurality of charge-coupled devices (CCDs) arranged in an array format. Each of the charge-coupled devices (CCDs) can serve as a pixel. The plurality of charge-coupled devices (CCDs) may be configured to detect color information of the plurality of lights reflected when modulated light having a plurality of focal points is focused on the surface of the measurement object 20. Based on the color information of the plurality of lights detected by the charge-coupled device (CCD), the respective heights above the surface of the measurement object 20 at which the plurality of lights are reflected can be measured.

[0076] A charge-coupled device (CCD) may be a 1-charge-coupled device (1CCD) consisting of one charge-coupled device, or a 3-charge-coupled device (hereinafter referred to as a 3CCD) having three separated charge-coupled devices. For example, referring to FIG. 9, a 3-charge-coupled device (3CCD) may include three separated charge-coupled devices: 3CCD-R, 3CCD-G, and 3CCD-B. Each of the three separated charge-coupled devices, 3CCD-R, 3CCD-G, and 3CCD-B, is located on the path of light separated into R, G, and B components by prisms A, B, and C, and can detect the R, G, and B components of light. The 3-charge-coupled device (3CCD) detects the R, G, and B components separated by prisms A, B, and C with each charge-coupled device, thereby providing higher color reproducibility and image quality than a 1-charge-coupled device (1CCD) system.

[0077] In another embodiment (not shown), the image sensor 400 may include a complementary metal oxide semiconductor (CMOS). The CMOS may be configured to include a plurality of pixels. Light reaching each pixel may be focused on a photodiode to generate electrons, and the generated electrons may be converted into a voltage to detect light information.

[0078] The image sensor 400 may include any one of a color camera, a multi-spectral camera, or a mono camera with a bandpass filter, but the image sensor 400 of the present disclosure is not limited thereto and includes any device capable of detecting RGB information of light.

[0079] The color information of the light detected by the image sensor 400 may include RGB information. For example, the color information of the light detected by a 3-charge coupled device (3CCD) of the image sensor 400 may include RGB information. The RGB information may be RGB information of light that is refracted according to wavelength and focused and reflected at a position corresponding to the height on the surface of the measurement target 20.

[0080] The image sensor 400 may be configured to obtain light wavelength information based on the detected RGB information.

[0081] In one embodiment not shown, a lookup table is created in which wavelength information corresponding to RGB information is tabulated in advance, so that the RGB information detected by the image sensor 400 can be converted into light wavelength information.

[0082] In another embodiment referring to FIG. 10 , the image sensor 400 may be configured to convert RGB information into another coordinate system to acquire wavelength information of light focused and reflected on the surface of the measurement target 20. The other coordinate system may be an HSV coordinate system or a CIE XYZ coordinate system. For example, the RGB information detected by the image sensor 400 may be converted into the HSV coordinate system using the following Equations 1, 2, and 3 to acquire wavelength information of light using the HSV information. H is a value representing hue and has values ​​from 0° to 360°, where 0° and 360° may represent red hue. S is a value representing saturation, where 100% represents the darkest state, and 0% represents an achromatic color of the same brightness. V is a value representing brightness, where white is 100% and black is 0%. Since the wavelength information of a light source according to the H value of the light source is a predetermined value (for example, when H is 0° or 360°, the wavelength of red light is 625 to 740 nm), the wavelength information of the light source can be detected by the H value obtained by HSV coordinate system transformation.

[0083] [Formula 1] JPEG2025534997000002.jpg1543 JPEG2025534997000003.jpg1969

[0084] [Formula 2] JPEG2025534997000004.jpg1473

[0085] [Formula 3] JPEG2025534997000005.jpg1331

[0086] Furthermore, in a CIE chromaticity diagram obtained by converting RGB information into the CIE XYZ coordinate system, the dominant wavelength, which is the wavelength of the monochromatic light closest to the chromaticity coordinate of the light source, may be detected. The HSV coordinate system and the CIE XYZ coordinate system described above are merely examples for explaining the present disclosure, and any coordinate system capable of obtaining wavelength information of light may be used.

[0087] Fig. 11 is a schematic diagram showing the operation of a three-dimensional shape inspection device according to an embodiment of the present disclosure. Fig. 12 is a graph illustrating the operation of the filter unit that blocks light of a specific wavelength or more in Fig. 11. The inspection method of the three-dimensional shape inspection device 10 according to the present disclosure will be described below with reference to Figs. 5, 6, 11, and 12.

[0088] Referring to FIG. 11 , the spatial light modulator 110 modulates light L received from a light source and irradiates the light onto the surface of the measurement object 20. An optical system for transmitting the light may be arranged on a path from the spatial light modulator 110 to the measurement object 20 where the light is irradiated. For example, the optical system may include multiple lenses 211, 212, 214, and 241 arranged on the path. An optical splitter 231 may be arranged on a path from the spatial light modulator 110 to the measurement object 20 where the light is irradiated. The optical splitter 231 can form an optical path from the spatial light modulator 110 to the measurement object 20 by reflecting the received light. The optical system may include a lens 242 located before the light is irradiated onto the measurement object 20. The lens 242 may be composed of multiple lenses. The lens 242 may be an objective lens. The light reflected on the surface of the measurement object 20 is configured to be transmitted to the image sensor 400. The image sensor 400 may include a first detection unit 410 and a second detection unit 420 .

[0089] An optical system may be arranged to transmit light reflected from the measurement object 20 on a path to the first detection unit 410. An optical system may be arranged to transmit light reflected from the measurement object 20 on a path to the second detection unit 420. For example, the optical system may include a plurality of lenses 241, 214, 212, and 215 arranged on the path to the first detection unit 410. The optical system may also include a plurality of lenses 241, 214, 212, and 216 arranged on the path to the second detection unit 420. An optical splitter 231 may be arranged on the path from the measurement object 20 to the first detection unit 410 or the second detection unit 420. The optical splitter 231 transmits the received light, thereby forming an optical path from the measurement object 20 to the first detection unit 410 or the second detection unit 420.

[0090] The three-dimensional shape inspection device 10 may include an optical splitter 232 arranged on a path of light from the optical splitter 231 to the first detection unit 410 or the second detection unit 420. The optical splitter 232 may be configured to transmit a portion of the light reflected from the measurement object 20 and to reflect another portion of the light reflected from the measurement object 20. The optical splitter 232 can form an optical path from the optical splitter 231 to the first detection unit 410 by transmitting received light. Information about the light that has transmitted through the optical splitter 232 may be detected by the first detection unit 410. The optical splitter 232 can form an optical path from the optical splitter 231 to the second detection unit 420 by reflecting received light. Information about the light reflected from the optical splitter 232 may be detected by the second detection unit 420.

[0091] The first and second detection units 410 and 420 can measure the height of the measurement object 20 by detecting information about light that is focused and reflected at a position corresponding to the height on the surface of the measurement object 20, among the light refracted according to wavelength. The light information may be information about the wavelength of the light. The first and second detection units 410 and 420 may be configured to detect color information about light that is focused and reflected at a position corresponding to the height of the base 22 of the measurement object 20 or the height of the transparent body 24 disposed on the base 22, among the light refracted according to wavelength.

[0092] In one embodiment, the three-dimensional shape inspection device 10 may include a control unit that measures the height of the base of the object to be measured and the height of a transparent body placed on the base based on information detected by the first detection unit and information detected by the second detection unit.

[0093] The optical path formed so that the light L emitted from the light source can be reflected by the object to be measured 20 and transmitted to the first detection unit 410 or the second detection unit 420 is not limited to the above, and any optical path may be formed by arranging a lens, a reflecting unit 220, and optical splitters 231, 232.

[0094] The 3D shape inspection device 10 may include a focus adjustment unit configured to change the measurement area by vertically changing the position where light refracted by the optical system according to wavelength is focused. For example, the focus adjustment unit may be embodied as a means for changing the position of the optical system according to the embodiments described below, or may be embodied as a means constituting a part of the optical system and capable of changing the position where light is focused.

[0095] The focus adjusting unit may change a position where light refracted according to wavelength is focused. The focus adjusting unit may change the position where light is focused in an up-down direction. The focus adjusting unit may be configured to change a measurement section where light refracted according to wavelength is focused. The focus adjusting unit may change a position where the shortest wavelength among light refracted according to wavelength is focused in an up-down direction. The focus adjusting unit may change a position where the longest wavelength among light refracted according to wavelength is focused in an up-down direction. The focus adjusting unit may change a position where light having a wavelength between the shortest wavelength and the longest wavelength among light refracted according to wavelength is focused in an up-down direction.

[0096] In one embodiment not shown, the focus adjustment unit can be operated by a mechanical means for adjusting the position of the optical system to change the measurement zone. The focus adjustment unit may be configured to be able to change the measurement zone by moving the optical system vertically.

[0097] 11, the focus adjustment unit 240 can form part of the optical system. The following description will be given based on the embodiment shown in FIG.

[0098] The optical system may include a focus adjustment unit 240. The focus adjustment unit 240 may be operated by electronic means that changes the measurement range by applying a current or the like. The focus adjustment unit 240 may include a variable lens 241 configured to change the measurement range based on the applied current. In the present disclosure, the focus adjustment unit 240 is disposed on the optical path immediately before the light is irradiated onto the measurement object 20, but is not limited to this, and the focus adjustment unit 240 may be disposed at any point on the optical path from the light source to the first detection unit 410 and the second detection unit 420.

[0099] Referring to FIG. 12, the filter section 430 that blocks light having wavelengths equal to or greater than a specific wavelength will be described.

[0100] Either the first detection unit 410 or the second detection unit 420 may be a filter detection unit. The filter detection unit may include a filter unit 430 that blocks light having a wavelength equal to or greater than a specific wavelength λ0. For example, the specific wavelength may be any wavelength λ0, as shown in FIG. 12 . The filter detection unit may be configured to detect information about light having a wavelength less than the specific wavelength λ0. While the present disclosure describes the second detection unit 420 as a filter detection unit and including the filter unit 430, the present disclosure is not limited thereto. An embodiment in which the first detection unit 410 is a filter detection unit including a filter unit is also possible. While the present disclosure illustrates an embodiment in which the filter unit 430 is disposed on the optical path toward the second detection unit 420, the present disclosure is not limited thereto. The filter unit 430 may include an optical filter that is disposed on the optical path and operated by a mechanical means, or an optical filter that is not disposed on the optical path and operated by an electronic means. The optical filter may be a short-pass filter.

[0101] The first detector and the second detector may be configured to detect light intensity information. The filter detector may be configured to detect light intensity information.

[0102] Fig. 13 is a schematic diagram showing light refracted by the optical system according to wavelength and focused and reflected at a position corresponding to the height of the base of the measurement object or the height of a transparent body placed on the base. Fig. 14 is a graph showing a situation in which the light intensity information detected by the filter detection unit is determined to be equal to or less than a predetermined first specific intensity. Fig. 15 is a graph showing a situation in which the light intensity information detected by the filter detection unit is determined to be equal to or greater than a predetermined second specific intensity. Fig. 16 is a graph showing a situation in which the light intensity information detected by the filter detection unit satisfies a predetermined standard.

[0103] 13 and 16, an inspection method of the three-dimensional shape inspection device will be described in the case where the measurement object 20 includes a transparent body 24.

[0104] When the measurement object 20 includes a base 22 and a transparent body 24, some of the light refracted by the optical system according to wavelength may be focused at a position corresponding to the height of the base 22 or the height of the transparent body 24. λ1 shown in Figures 13 to 16 is defined as the wavelength of the light focused at the position corresponding to the height of the transparent body 24, and λ2 is defined as the wavelength of the light focused at the position corresponding to the height of the base 22.

[0105] The first detection unit 410 and the second detection unit 420 may be configured to detect wavelength information of light that is focused and reflected at a position corresponding to the height of the base 22 of the measurement object 20 or the height of the transparent body 24 disposed on the base 22, among light refracted according to wavelength. The filter detection unit, which is either the first detection unit 410 or the second detection unit 420, may be configured to detect information of light having a wavelength less than a specific wavelength λ0 using the filter unit 430 that blocks light having a wavelength equal to or greater than a specific wavelength λ0.

[0106] 14 to 16, (a) of Fig. 14 to 16 are graphs showing information on light detected by a no-filter detection unit, which is not a filter detection unit, of the first detection unit and the second detection unit. (b) of Fig. 14 to 16 are graphs showing information on light detected by a filter detection unit, which is one of the first detection unit and the second detection unit. (c) of Fig. 14 to 16 are graphs showing information on light detected by both the filter detection unit and the no-filter detection unit.

[0107] 14 to 16(a), the no-filter detection unit can detect the wavelength λ1 of light focused and reflected at a position corresponding to the height of the transparent body 24 and the wavelength λ2 of light focused and reflected at a position corresponding to the height of the base 22. The intensity of the wavelength λ2 of light focused and reflected at a position corresponding to the height of the base 22, detected by the no-filter detection unit, and the intensity of the wavelength λ1 of light focused and reflected at a position corresponding to the height of the transparent body 24, may differ from each other. In the present disclosure, the intensity of the wavelength λ1 of light focused and reflected at a position corresponding to the height of the transparent body 24 has a very small value, so the present disclosure will be described based on an example not shown in FIGS. 14 to 16(a), but the present disclosure is not limited thereto.

[0108] Depending on the wavelength λ1 of the light focused at the position corresponding to the height of the transparent body 24, the wavelength λ2 of the light focused at the position corresponding to the height of the base 22, and the magnitude of the specific wavelength value of the filter section, three situations may exist: (1) λ0<λ1<λ2, (2) λ1<λ2<λ0, and (3) λ1<λ0<λ2.

[0109] Referring to FIG. 14, situation (1) will be described. Light focused and reflected at a position corresponding to the height of the base 22 or the height of the transparent body 24 of the measurement object 20 all has a wavelength greater than the specific wavelength λ0. Because the filter detection unit includes a filter unit 430 that blocks light with wavelengths greater than the specific wavelength λ0, light focused and reflected at a position corresponding to the height of the base 22 or the height of the transparent body 24 of the measurement object 20 may be blocked by the filter unit 430 (see FIG. 14(b)). Referring to a graph showing information on light detected by both the filter detection unit and the no-filter detection unit (see FIG. 14(c)), only information for one wavelength λ2 focused and reflected at the surface of the base can be detected, making inspection of the measurement object 20 impossible.

[0110] Referring to FIG. 15, situation (2) will be described. All of the light focused and reflected at a position corresponding to the height of the base 22 or the height of the transparent body 24 of the measurement object 20 has a wavelength smaller than the specific wavelength λ0. Because the filter detection unit includes a filter unit 430 that blocks light with wavelengths equal to or greater than the specific wavelength λ0, all of the light focused and reflected at a position corresponding to the height of the base 22 or the height of the transparent body 24 of the measurement object 20 may not be blocked by the filter unit 430 (see FIG. 15(b)). Regarding a graph showing information on light detected by both the filter detection unit and the no-filter detection unit (see FIG. 15(c)), the filter detection unit detects information on the two wavelengths λ1 and λ2 that are not blocked by the filter unit 430, and thus light information on a wavelength λmix, which is a mixture of the two wavelengths λ1 and λ2, may be detected. The mixed wavelength λmix contains information on the two wavelengths λ1 and λ2. The intensity value of the light corresponding to the mixed wavelength λmix may have an intensity greater than or equal to the specific saturation intensity S. Since the wavelength information of the light detected by the filter detection unit and the non-filter detection unit contains a mixed wavelength λmix, it is not possible to measure the height corresponding to a specific wavelength, making it impossible to inspect the measurement object 20.

[0111] Situation (3) will be described with reference to FIG. 16. The wavelength λ2 of light focused and reflected at a position corresponding to the height of the base 22 of the measurement object 20 may be greater than the specific wavelength λ0, and the wavelength λ1 of light focused and reflected at a position corresponding to the height of the transparent body 24 may be smaller than the specific wavelength λ0. The filter detection unit includes a filter unit 430 that blocks light of wavelengths equal to or greater than the specific wavelength λ0, so that the light focused and reflected at a position corresponding to the height of the base 22 of the measurement object 20 can be blocked by the filter unit 430. For example, the filter detection unit can block the light focused and reflected at a position corresponding to the height of the base 22 and detect information regarding the wavelength λ1 of the light focused and reflected at a position corresponding to the height of the transparent body 24 (see FIG. 16(b)). Regarding the graph showing both the information on the light detected by the filter detection unit and the no-filter detection unit (see (c) of Figure 16), inspection can be performed based on the wavelength λ2 information of the light focused and reflected at a position corresponding to the height of the base 22 detected by the no-filter detection unit and the wavelength λ1 information of the light focused and reflected at a position corresponding to the height of the transparent body 24 detected by the filter detection unit.

[0112] In situation (1) of FIG. 14, the control unit may determine that the light intensity information detected by the filter detection unit is equal to or less than a predetermined first specific intensity. The predetermined first specific intensity may be any very small value. When the control unit determines that the light intensity information detected by the filter detection unit is equal to or less than the predetermined first specific intensity, the control unit may be configured to control the focus adjustment unit 240 to change the measurement section. The control unit may be configured to control the focus adjustment unit 240 to change the measurement section to achieve the condition of situation (3).

[0113] When the light intensity information is determined to be equal to or less than a predetermined first specific intensity, the control unit may control the focus adjustment unit 240 to change the measurement section so that light with a shorter wavelength is reflected by the measurement object 20. When the light intensity information is determined to be equal to or less than a predetermined first specific intensity, the control unit may control the focus adjustment unit 240 to change the measurement section so that light with a shorter wavelength is reflected by the transparent body 24. When the light intensity information is determined to be equal to or less than a predetermined first specific intensity, the control unit may control the focus adjustment unit 240 to move the measurement section downward so that light with a shorter wavelength is reflected by the transparent body 24. When the light intensity information is determined to be equal to or less than a predetermined first specific intensity, the control unit may control the focus adjustment unit 240 to move the measurement section downward so that light with a wavelength shorter than a specific wavelength λ0 is reflected by the transparent body 24. When the light intensity information is determined to be equal to or less than a predetermined first specific intensity, the control unit may control the focus adjustment unit 240 to move the measurement section downward to a point where light with a wavelength longer than a specific wavelength λ0 is reflected by the base 22.

[0114] In situation (2) of FIG. 15 , the control unit may determine that the light intensity information detected by the filter detection unit is equal to or greater than a predetermined second specific intensity S. The predetermined second specific intensity may be any value. When the control unit determines that the light intensity information detected by the filter detection unit is equal to or greater than the predetermined second specific intensity, the control unit may be configured to control the focus adjustment unit 240 to change the measurement section. The control unit may be configured to control the focus adjustment unit 240 to change the measurement section so as to achieve the condition of situation (3).

[0115] When the light intensity information is determined to be equal to or greater than the second specific intensity, the control unit can control the focus adjustment unit 240 to change the measurement section so that light with a longer wavelength is reflected by the measurement object 20. When the light intensity information is determined to be equal to or greater than the second specific intensity, the control unit can control the focus adjustment unit 240 to change the measurement section so that light with a longer wavelength is reflected by the base 22. When the light intensity information is determined to be equal to or greater than the second specific intensity, the control unit can control the focus adjustment unit 240 to move the measurement section upward so that light with a longer wavelength is reflected by the transparent body 24. When the light intensity information is determined to be equal to or greater than the second specific intensity, the control unit can control the focus adjustment unit 240 to move the measurement section upward so that light with a wavelength longer than the specific wavelength λ0 is reflected by the base 22. When the control unit determines that the light intensity information is equal to or greater than a predetermined second specific intensity, the control unit can control the focus adjustment unit 240 to move the measurement section upward to a point where light having a wavelength smaller than the specific wavelength λ0 is reflected by the transparent body 24.

[0116] In situation (3) of Figure 16, the control unit can determine that the predetermined criterion is met when the light intensity information is equal to or greater than the first specific intensity and equal to or less than the second specific intensity. The control unit can determine that the predetermined criterion is not met when the light intensity information is equal to or less than the first specific intensity or equal to or greater than the second specific intensity.

[0117] FIG. 17 is a schematic diagram showing how a three-dimensional shape inspection device according to an embodiment of the present disclosure can perform inspection regardless of the shapes of the base and the transparent body.

[0118] 4 and 17, the 3D shape inspection device 50 according to the comparative example of FIG. 4 does not include a separate focus adjustment unit, and therefore may not be able to inspect depending on the shape of the test piece. However, the 3D shape inspection device 10 according to an embodiment of the present disclosure includes a focus adjustment unit 240, and is configured to be able to change the measurement section by vertically changing the position where refracted light for each wavelength is focused.

[0119] Inspection is possible by adjusting the measurement range vertically using the focus adjuster 240, not only for the case where wavelengths λ11 and λ12 of light refracted according to wavelength are focused and reflected at a position corresponding to the height of the base 22 or the transparent body 24 as shown in FIG. 17(a), but also for a test piece having a very thick base 22 as shown in FIG. 17(b) or a test piece having a very thick transparent body 24 as shown in FIG. 17(c). In the case of FIG. 4(b), the measurement range is adjusted upward using the focus adjuster 240, and information on wavelengths λ21 and λ22 of light focused and reflected at a position corresponding to the height of the base 22 or the transparent body 24 can be detected as shown in FIG. 17(b). In the case of FIG. 4(c), the measurement range is adjusted downward using the focus adjuster 240, and information on wavelengths λ31 and λ32 of light focused and reflected at a position corresponding to the height of the base 22 or the transparent body 24 can be detected as shown in FIG. 17(c).

[0120] 18 is a schematic diagram illustrating a method for measuring the height of a base of a measurement object and the height of a transparent body placed on the base by a 3D shape inspection apparatus according to an embodiment of the present disclosure. FIG. 19 is a graph showing a focal shift value specific to each wavelength of an optical system according to an embodiment of the present disclosure.

[0121] Referring to FIG. 18, the control unit can control the focus adjustment unit 240 to change the measurement section when the light intensity information satisfies a predetermined criterion, which is situation (3) in FIG. 16. A first state, which is before the measurement section is changed due to the predetermined criterion being satisfied, is shown in FIG. 18(a), and a second state, which is after the measurement section is changed due to the predetermined criterion being satisfied, is shown in FIG. 18(b). The first detection unit 410 and the second detection unit 420 may be configured to again detect information regarding the wavelength of light when the measurement section has been changed. The first detection unit 410 and the second detection unit 420 may be configured to detect information regarding the wavelengths λ3 and λ4 of light focused and reflected by the base 22 and the transparent body 24 when the measurement section has been changed.

[0122] The control unit may be configured to acquire first information detected by the no-filter detection unit (not the filter detection unit) of the first detection unit 410 and the second detection unit 420, which is not a filter detection unit, in a first state before the measurement range is changed, and acquire second information detected by the filter detection unit. The first information may be information about the wavelength λ1 of light focused and reflected by the base 22. The second information may be information about the wavelength λ2 of light focused and reflected by the transparent body 24. The control unit may be configured to acquire third information detected by the no-filter detection unit and fourth information detected by the filter detection unit in a second state after the measurement range is changed. Although the present disclosure will be described based on the first state being changed to the second state by changing the measurement range upward, the present disclosure is not limited thereto, and an embodiment in which the second state is changed to the second state by changing the measurement range downward is also possible. The third information may be information about the wavelength λ3 of light focused and reflected by the base 22. The fourth information may be information about the wavelength λ4 of light focused and reflected by the transparent body 24. The wavelength λ3 of the third information may be greater than the wavelength λ1 of the first information. The wavelength λ4 of the fourth information may be greater than the wavelength λ2 of the second information. In this disclosure, the description will be based on the assumption that the no-filter detection unit is the first detection unit 410 and the filter detection unit is the second detection unit 420, but the present disclosure is not limited to this, and an embodiment in which the no-filter detection unit is the second detection unit 420 and the filter detection unit is the first detection unit 410 is also possible.

[0123] The control unit may be configured to measure the height of the base 22 of the object to be measured 20 and the height of the transparent body 24 placed on the base 22 based on the first information, the second information, the third information, the fourth information, and the refractive index.

[0124] The control unit may be configured to measure the height of the base 22 of the measurement object and the height of the transparent body 24 disposed on the base 22 based on the first information, the second information, the third information, and the fourth information. The control unit may be configured to measure the refractive index n of the transparent body based on the working distance in the first state, the working distance in the second state, the first information, and the third information. The working distance may be defined as a value proportional to the average distance from the optical system to a position where light refracted according to wavelength is focused. That is, the working distance may change depending on the average distance from the optical system to a point where light refracted according to wavelength is focused by the focus adjustment unit 240. For example, as shown in FIG. 18 , the second state may be a state where the average distance from the optical system to a point where light refracted according to wavelength is focused is smaller than that in the first state. The working distance WD2 in the second state may be smaller than the working distance WD1 in the first state. The working distance may be a value that increases depending on the current applied to the focus adjustment unit 240.

[0125] An optical system may have a unique chromatic focal shift for each wavelength due to chromatic aberration (see FIG. 19). An optical system may have a unique focal shift depending on how it is designed. The unique focal shift due to chromatic aberration is a measure of chromatic aberration and may be a value that quantifies the degree of change in the focal position at which multiple wavelengths are focused for each optical field.

[0126] The working distance WD1 in the first state, the working distance WD2 in the second state, and the chromatic focal shift value specific to each wavelength satisfy the following Equations 4, 5, and 6. Equation 6 is an equation obtained by rearranging the terms in Equation 5 with respect to the refractive index n of the transparent body.

[0127] Referring to Equation 4, the value obtained by subtracting the second focal shift value (Focal shift(λ2)) corresponding to the second information from the fourth focal shift value (Focal shift(λ4)) corresponding to the fourth information may be the value obtained by subtracting the working distance WD1 in the first state from the working distance WD2 in the second state. Referring to Equation 5, the value obtained by subtracting the first focal shift value (Focal shift(λ1)) corresponding to the first information from the third focal shift value (Focal shift(λ3)) corresponding to the third information multiplied by the refractive index may be the value obtained by subtracting the working distance WD1 in the first state from the working distance WD2 in the second state.

[0128] Referring to Equation 6, the refractive index may be calculated by subtracting the working distance WD2 in the second state from the working distance WD1 in the first state, and dividing the result by subtracting the first focal shift value (Focal shift(λ1)) corresponding to the first information from the third focal shift value (Focal shift(λ3)) corresponding to the third information. The value obtained by subtracting the working distance WD2 in the second state from the working distance WD1 in the first state may be increased as the current applied to the focus adjustment unit 240 increases. In other words, by creating a table of working distance values ​​corresponding to the current applied to the focus adjustment unit 240, the value obtained by subtracting the working distance WD2 in the second state from the working distance WD1 in the first state can be determined based on the value of the current applied to the focus adjustment unit 240.

[0129] [Formula 4] JPEG2025534997000006.jpg878

[0130] [Formula 5] JPEG2025534997000007.jpg685

[0131] [Formula 6] JPEG2025534997000008.jpg1264

[0132] FIG. 20 is a flowchart showing the flow of an embodiment of the three-dimensional shape inspection method of the present disclosure.

[0133] Referring to Figures 5, 6, 11, and 20, the 3D shape inspection method (S10) may include a white light irradiation step (S101), a DLP multiple pattern irradiation step (S102), a measurement object irradiation step (S103), and a wavelength signal reflection step corresponding to the height of the measurement object (S104).

[0134] The DLP multi-pattern illumination step (S102) may be a step of modulating the light received in the white light illumination step (S101). The DLP multi-pattern illumination step (S102) may be configured to modulate the light L received from the light source so as to illuminate the surface of the measurement object 20 with a plurality of lights having a plurality of foci. In the DLP multi-pattern illumination step (S102), light modulation may be performed by the spatial light modulator 110. The DLP multi-pattern illumination step (S102) may correspond to a light modulation step.

[0135] The measurement object irradiating step (S103) may be configured to refract each of the lights modulated in the DLP multiple pattern irradiating step (S102) with different refractive indices for each of a plurality of wavelengths due to chromatic aberration, and irradiate the light downward to form a measurement zone in the vertical direction where the refracted light for each wavelength is focused. The modulated light in the measurement object irradiating step (S103) may form the measurement zone through an optical system. The measurement object irradiating step (S103) may correspond to the light irradiating step.

[0136] The step of reflecting a wavelength signal corresponding to the height of the measurement object (S104) may be a step of reflecting focused light at a position corresponding to the height on the surface of the measurement object 20, among the light refracted according to wavelength irradiated onto the measurement object in the step of irradiating the measurement object (S103).

[0137] The 3D shape inspection method (S10) may include a light path forming step of transmitting a portion of the light reflected by the measurement object and reflecting another portion of the light reflected by the measurement object. The light path forming step may be performed by an optical splitter 230.

[0138] The 3D shape inspection method (S10) may include an information acquiring step of detecting color information of light that is focused and reflected at a position corresponding to a height on the surface of the measurement target 20, among light refracted by wavelength in the measurement section. The information acquiring step may include a first detecting step of detecting information about the wavelength of light that has passed through the light path forming step. The information acquiring step may include a second detecting step of detecting information about the wavelength of light that has been reflected in the light path forming step. The first detecting step and the second detecting step may be performed by a first detecting unit 410 and a second detecting unit 420.

[0139] The information acquisition step may include an image acquisition step (S105), an RGB information acquisition step (S106), a coordinate system conversion step (S107), and a wavelength information confirmation step (S108). The first detection step and the second detection step may include an image acquisition step (S105), an RGB information acquisition step (S106), a coordinate system conversion step (S107), and a wavelength information confirmation step (S108).

[0140] The image acquiring step (S105) may be a step of receiving an image or information of light reflected from the light focused at a position corresponding to the height on the surface of the measurement object 20. The image acquiring step (S105) may be configured to receive the light reflected from the measurement object 20 using the image sensor 400. The RGB information acquiring step (S106) may be a step of acquiring RGB information of the light received in the image acquiring step (S105). The RGB information acquiring step (S106) may be configured to acquire the RGB information of the light using a 3CCD (3CCD) of the image sensor 400.

[0141] The coordinate system conversion step (S107) may include converting the RGB information acquired in the RGB information acquisition step (S106) into another coordinate system (e.g., HSV coordinate system or CIE XYZ coordinate system). The wavelength information confirmation step (S108) may include confirming wavelength information of light based on the information acquired in the coordinate system conversion step (S107). As described above, the wavelength information confirmation step (S108) may confirm wavelength information of light using an H value in the HSV coordinate system or dominant wavelength information in the CIE XYZ coordinate system.

[0142] The 3D shape inspection method (S10) may include a measurement object height confirmation step (S109) of measuring the height of the surface of the measurement object based on the color information detected in the information acquisition step. In the measurement object height confirmation step (S109), the height of the measurement object can be measured by detecting color information of light that is focused and reflected at a position corresponding to the height on the surface of the measurement object 20, among light refracted according to wavelength. The light information detected in the measurement object height confirmation step (S109) may be information of light that is focused and reflected at a position corresponding to the height on the surface of the base 22 and transparent body 24 of the measurement object 20.

[0143] The three-dimensional shape inspection method (S10) may include a 3D inspection proceeding step (S110) after the measurement object height confirmation step. The 3D inspection proceeding step may include at least one of the above-described steps (S101 to S109), and these steps (S101 to S109) may be performed multiple times to perform inspection on multiple surfaces of the measurement object 20.

[0144] The 3D shape inspection method (S10) may include a focus adjustment step of changing a measurement area by vertically changing a position where refracted light for each wavelength is focused. The focus adjustment step may be a step of changing the measurement area by the focus adjustment unit 240. The focus adjustment step may be performed before the white light irradiation step (S101) or before the white light irradiation step in the 3D inspection proceeding step (S110) which is performed at least once, so that the focus adjustment step may be performed multiple times.

[0145] FIG. 21 is a flowchart showing the flow of an embodiment of a three-dimensional shape inspection method according to the present disclosure when a transparent body is included in the measurement target.

[0146] The 3D shape inspection method (S10) may include a transparent body test piece placement step (S201), a vertical scanning step (S202), a predetermined reference determination step (S203), a measurement section setting step (S204), a transparent body refractive index confirmation step (S205), and an entire measurement object measurement step (S206).

[0147] The transparent body test piece placement step (S201) may be a step of placing the transparent body 24 on the base 22. The vertical scanning step (S202) may include a focus adjustment step. The vertical scanning step (S202) may be a step of vertically changing the position where the refracted light for each wavelength is focused, thereby vertically changing the measurement section.

[0148] The predetermined criterion determination step (S203) may include a first detection step of detecting information about the wavelength of light transmitted in the light path formation step, and a second detection step of detecting information about the wavelength of light reflected in the light path formation step. Either the first detection step or the second detection step may include a filter detection step of blocking light having a wavelength equal to or greater than a specific wavelength and detecting information about light having a wavelength less than the specific wavelength. The filter detection step may be configured to detect light intensity information.

[0149] The predetermined criterion determining step (S203) may be a step of determining whether the light intensity information is equal to or less than a predetermined first specific intensity or equal to or greater than a predetermined second specific intensity. When the light intensity information is equal to or less than the predetermined first specific intensity or equal to or greater than the predetermined second specific intensity, the vertical scanning step (S202) may be performed again. When the light intensity information is determined to be equal to or less than the predetermined first specific intensity or equal to or greater than the predetermined second specific intensity, the predetermined criterion determining step (S203) may include a focus adjusting step of changing the measurement zone by vertically changing the position where refracted light according to wavelength is focused. When the light intensity information is equal to or less than the predetermined first specific intensity in the predetermined criterion determining step (S203), the subsequent focus adjusting step may include moving the measurement zone downward. When the light intensity information is equal to or greater than the predetermined second specific intensity in the predetermined criterion determining step (S203), the subsequent focus adjusting step may include moving the measurement zone upward.

[0150] The measurement interval setting step (S204) may be performed when the light intensity information satisfies a predetermined criterion in the predetermined criterion determination step (S203). The predetermined criterion may be a state in which the light intensity information is equal to or greater than a predetermined first specific intensity and equal to or less than a predetermined second specific intensity. The measurement interval setting step (S204) may include a focus adjustment step of changing the measurement interval by vertically changing the position where refracted light according to wavelength is focused when the light intensity information satisfies the predetermined criterion. After the measurement interval setting step (S204) has been changed, the first detection step and the second detection step may be performed again.

[0151] The measurement interval setting step (S204) may be configured to acquire first information detected in a no-filter detection step that is not a filter detection step among the first detection step and the second detection step, and acquire second information detected in the filter detection step, in a first state before the measurement interval is changed. The measurement interval setting step (S204) may be configured to acquire third information detected in the no-filter detection step and fourth information detected in the filter detection step, in a second state after the measurement interval is changed.

[0152] The step of confirming the refractive index of the transparent body (S205) may be configured to measure the refractive index n of the transparent body based on the working distance in the first state, the working distance in the second state, the first information, and the third information. The method of measuring the refractive index n in the step of confirming the refractive index of the transparent body (S205) may be the same as the method of measuring the refractive index in the three-dimensional shape inspection apparatus 10.

[0153] The entire measurement object measuring step (S206) may be configured to measure the height of the base of the measurement object and the height of the transparent body placed on the base based on the first information, second information, third information, and fourth information acquired in the measurement section setting step (S204) and the refractive index measured in the transparent body refractive index confirmation step (S205).

[0154] Although the technical idea of ​​the present disclosure has been described above by way of some embodiments and examples shown in the accompanying drawings, it should be understood that various substitutions, modifications, and changes can be made without departing from the technical idea and scope of the present disclosure, which can be understood by those skilled in the art to which the present disclosure pertains. Furthermore, such substitutions, modifications, and changes should be considered to fall within the scope of the appended claims.

Claims

1. a light irradiation unit including a light source and a spatial light modulator configured to modulate light received from the light source, and configured to irradiate a plurality of lights having a plurality of focal points downward onto a surface of the measurement object; an optical system configured to refract each of the modulated lights with different refractive indices according to a plurality of wavelengths due to chromatic aberration, thereby forming measurement zones in an up-down direction in which the refracted lights according to wavelengths are focused; an optical splitter configured to transmit a portion of the light reflected by the object to be measured and to reflect another portion of the light reflected by the object to be measured; a first detector that detects information about the wavelength of light transmitted through the optical splitter; a second detector that detects information about the wavelength of the light reflected from the optical splitter; A three-dimensional shape inspection device, wherein a filter detection unit, which is either one of the first detection unit or the second detection unit, is configured to have a filter unit that blocks light of a specific wavelength or more and detect information about light of a wavelength less than the specific wavelength.

2. 2. The three-dimensional shape inspection device according to claim 1, further comprising a control unit that measures the height of a base of the measurement object and the height of a transparent body placed on the base based on the information detected by the first detection unit and the information detected by the second detection unit.

3. The three-dimensional shape inspection device according to claim 1 , wherein the filter detection unit is configured to detect light intensity information.

4. a focus adjustment unit configured to change the measurement section by vertically changing a position where the light refracted according to wavelength is focused; The three-dimensional shape inspection device according to claim 3 , further comprising a control unit configured to control the focus adjustment unit to change the measurement section when the light intensity information is determined to be equal to or less than a predetermined first specific intensity.

5. The control unit 5. The three-dimensional shape inspection device according to claim 4, wherein when the light intensity information is determined to be equal to or less than a predetermined first specific intensity, the focus adjustment unit is controlled to change the measurement section so that light of a shorter wavelength is reflected by the object to be measured.

6. a focus adjustment unit configured to change the measurement section by vertically changing a position where the light refracted according to wavelength is focused; 4. The three-dimensional shape inspection device according to claim 3, further comprising: a control unit configured to control the focus adjustment unit to change the measurement section when the light intensity information is determined to be equal to or greater than a predetermined second specific intensity.

7. The control unit 7. The three-dimensional shape inspection device according to claim 6, wherein when the light intensity information is determined to be equal to or greater than a predetermined second specific intensity, the focus adjustment unit is controlled to change the measurement section so that light of a longer wavelength is reflected by the measurement object.

8. a focus adjustment unit configured to change the measurement section by vertically changing a position where the light refracted according to wavelength is focused; a control unit that controls the focus adjustment unit to change the measurement section when the light intensity information satisfies a predetermined criterion, The three-dimensional shape inspection device according to claim 3 , wherein the first detection unit and the second detection unit are configured to detect information about the wavelength of light again in a state where the measurement section has been changed.

9. The control unit (i) in a first state before the measurement section is changed, first information detected by a no-filter detection unit that is not the filter detection unit out of the first detection unit and the second detection unit is acquired, and second information detected by the filter detection unit is acquired; (ii) in a second state after the measurement section is changed, third information detected by the no-filter detection unit and fourth information detected by the filter detection unit are acquired; (iii) The three-dimensional shape inspection device according to claim 8, configured to measure the height of a base of the measurement object and the height of a transparent body placed on the base based on the first information, the second information, the third information, and the fourth information.

10. When a value proportional to the average value of the distance from the optical system to the position where the light refracted by wavelength is focused is defined as a working distance, The control unit 10. The three-dimensional shape inspection device according to claim 9, configured to measure the refractive index of the transparent body based on the working distance in the first state, the working distance in the second state, the first information, and the third information.

11. The optical system has a unique focus shift value for each wavelength due to chromatic aberration, When a value proportional to the average value of the distance from the optical system to the position where the light refracted by wavelength is focused is defined as a working distance, The control unit 10. The three-dimensional shape inspection device according to claim 9, configured to measure a refractive index that is a value obtained by subtracting the working distance in the second state from the working distance in the first state, and dividing the value by the value obtained by subtracting the first focus shift value corresponding to the first information from a third focus shift value corresponding to the third information.

12. The control unit 12. The three-dimensional shape inspection device according to claim 11, configured to measure the height of a base of the measurement object and the height of a transparent body placed on the base based on the first information, the second information, the third information, the fourth information, and the refractive index.

13. the focus adjustment unit includes a variable lens configured to be able to change the measurement section based on an applied current; 12. The three-dimensional shape inspection device according to claim 11, wherein the greater the applied current, the greater the value obtained by subtracting the working distance in the second state from the working distance in the first state.

14. The three-dimensional shape inspection device according to claim 1 , wherein the filter detection unit is the second detection unit.

15. The spatial light modulator comprises: The three-dimensional shape inspection apparatus according to claim 1 , comprising a plurality of digital micromirror devices arranged in an array, configured to reflect and thereby modulate light received from the light source.

16. 2. The three-dimensional shape inspection device of claim 1, wherein the first detection unit and the second detection unit are configured to detect color information of light refracted according to wavelength that is focused and reflected at a position corresponding to the height of a base of the measurement object or the height of a transparent body placed on the base.

17. 2. The three-dimensional shape inspection device according to claim 1, wherein the light irradiation unit is configured to irradiate the surface of the measurement object downward with the plurality of lights having a plurality of focal points in a horizontal direction perpendicular to a vertical direction.

18. a light modulation step of modulating the light received from the light source so as to irradiate a surface of the measurement object with a plurality of light beams having a plurality of focal points; a light irradiation step of irradiating the modulated light downward to form a measurement section in an up-down direction where the light refracted according to wavelength is focused by refracting the modulated light with different refractive indices according to wavelengths due to chromatic aberration; forming an optical path by an optical splitter, which transmits a portion of the light reflected by the object to be measured and reflects another portion of the light reflected by the object to be measured; a first detecting step of detecting information about the wavelength of the light transmitted through the optical path forming step; a second detecting step of detecting information about the wavelength of the light reflected in the light path forming step, The three-dimensional shape inspection method, wherein one of the first detecting step and the second detecting step includes a filter detecting step of blocking light having a wavelength equal to or greater than a specific wavelength and detecting information about light having a wavelength less than the specific wavelength.

19. the filter detection step is configured to detect light intensity information; 20. The 3D shape inspection method of claim 18, further comprising a focus adjustment step of changing the measurement section by vertically changing a position where the refracted light for each wavelength is focused when the light intensity information is determined to be equal to or less than a predetermined first specific intensity or equal to or more than a predetermined second specific intensity.

20. the filter detection step is configured to detect light intensity information; If the luminous intensity information of the light satisfies a predetermined criterion, a focus adjusting step of changing the measurement section by vertically changing a position where the refracted light for each wavelength is focused is further included, The three-dimensional shape inspection method of claim 18 , wherein the first and second detection steps are performed again with the measurement section changed.

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