JP5332192B2 - 3D shape measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensional shape measuring apparatus capable of measuring a three-dimensional shape without mechanical movement of the device. <P>SOLUTION: A shape measuring apparatus 1 includes: a light source 2 capable of emitting light at a wavelength that varies within a predetermined band of wavelengths; a two-dimensional chart 3 having a recurring pattern; an objective optical system 7, having a predetermined amount of chromatic aberration, which projects, on a subject S, an image of the two-dimensional chart 3 illuminated by the light emitted from the light source 2; imaging devices 10 to 12 for picking up the projected image of the two-dimensional chart 3 with the projected image scattered by the subject S; and a control unit 13 for calculating a three-dimensional shape of the subject S in accordance with stored chart data and the amount of chromatic aberration of the objective optical system 7. The imaging devices 10 to 12 also store the projected image of the two-dimensional chart 3 as chart data in a storage area in correspondence with the wavelength of the light emitted from the light source 2 when the projected image of the two-dimensional chart 3 was obtained. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a three-dimensional shape measuring apparatus.

As an apparatus for optically measuring the three-dimensional shape of an object surface in a non-contact manner, an apparatus using axial chromatic aberration of an optical system is known (for example, see Patent Documents 1 and 2). In this type of apparatus, it is possible to measure a three-dimensional shape in a non-contact manner by using a projection optical system that intentionally has axial chromatic aberration and a light source that can output light of a plurality of wavelengths.
Japanese Patent No. 2812371 JP 7-229720 A

  When measuring the three-dimensional shape, mechanically changing the relative positional relationship between the object to be measured and the light projected onto the object to be measured increases the measurement time and requires a scanning mechanism. Therefore, the apparatus is also complicated.

  An object of the present invention is to provide a three-dimensional shape measuring apparatus that can measure a three-dimensional shape without mechanical movement of the apparatus.

  According to an embodiment illustrating the present invention, an apparatus for measuring a three-dimensional shape of a measurement object, a light source capable of changing the wavelength in a predetermined wavelength band and outputting light, and transmitting light A projection for projecting an image of a two-dimensional chart in which a pattern having a region is repeated along a predetermined direction and an image of the two-dimensional chart having a predetermined amount of chromatic aberration and illuminated by light output from a light source onto a measurement object A two-dimensional image picked up corresponding to the wavelength of the output light from the light source when the projection image of the two-dimensional chart scattered by the optical system and the object to be measured is obtained. An imaging unit that saves a projected image of the chart as chart data in a storage area; an imaging data processing unit that calculates a three-dimensional shape of the measurement object based on the chart data stored in the storage area and the amount of chromatic aberration of the projection optical system; With Dimension shape measuring apparatus is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the three-dimensional shape measuring apparatus which can measure a three-dimensional shape without accompanying the mechanical motion of an apparatus can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.
(First embodiment)

  With reference to FIG. 1, the structure of the shape measuring apparatus 1 which concerns on 1st Embodiment is demonstrated. FIG. 1 is a configuration diagram of a shape measuring apparatus according to the first embodiment.

  A shape measuring apparatus 1 shown in FIG. 1 includes a spectrum light source 2, a two-dimensional chart 3, a collimator 4, a polarizing beam splitter 5, a quarter wavelength plate 6, an objective optical system (projection optical system) 7, An imaging optical system 8, a wavelength band branching prism (branching unit) 9, a first imaging device 10, a second imaging device 11, a third imaging device 12, and a control unit 13 are provided. . The shape measuring apparatus 1 projects an image of the two-dimensional chart 3 illuminated with the light L output from the spectrum light source 2 onto the measured object S by the objective optical system 7, and the two-dimensional chart 3 on the measured object S. This is a device that measures the three-dimensional shape of the measurement object S by comparing the data obtained by capturing the scattered light of the projected image of this and the axial chromatic aberration of the objective optical system 7.

  The spectrum light source 2 has a plurality of (three in the present embodiment) wavelength bands, the first wavelength band WB1, the second wavelength band WB2, and the third wavelength band WB3, each having a different wavelength. The light of the partial wavelength band (spectrum) can be output simultaneously. Each of the plurality of partial wavelength bands is a partial wavelength band of any one of the first to third wavelength bands WB1, WB2, and WB3. The spectrum light source 2 outputs light L by changing the wavelength band (spectrum) among the wavelength bands WB1, WB2, and WB3. The spectrum light source 2 includes a light source device 21, a light source collimator 22, a diffusion element 23, and an illumination optical system 24.

  The light source device 21 outputs light L having a desired wavelength band. The light source collimator 22 collimates the light L output from the light source device 21 into a parallel light beam. The diffusing element 23 diffuses the light L that has been converted into a parallel light beam by the light beam collimator 22. As the diffusing element 23, for example, a diffusing plate or a fly-eye lens can be used.

  Here, the configuration of the light source device 21 will be described with reference to FIG. FIG. 2 is a configuration diagram of the light source device 21. As shown in FIG. 2, a continuous spectrum parallel light beam output from a light source unit 101 that outputs a parallel light beam B1 from a supercontinuum light source, which can be regarded as a point light source in terms of geometric optics, and has a feature of a continuous spectrum light source. B 1 is incident on the polarization splitting element 102. In FIG. 2, double-directional arrows and black circles attached to the light beams indicate vibration directions of polarized light that are perpendicular to each other. A light beam in which these two are described simultaneously indicates a light beam having both polarization components.

  The polarization splitting element 102 splits and outputs incident light as output light having two linearly polarized light components orthogonal to each other. For example, if a Wollaston prism made of a birefringent crystal such as calcite is used, a high extinction ratio (100,000) is obtained. : About 1). A Nomarski prism or the like may be used instead of the Wollaston prism. The polarization splitting element 102 is installed with a slight inclination so that the surface reflected light flux does not return to the light source point in the light source unit 101.

  In FIG. 2, the plane mirror 110 is installed to deflect the parallel light beam B1, but this may or may not be installed according to the necessity in arrangement.

  The parallel light beam B1 is decomposed into light beams B2 and B3 according to polarization components orthogonal to each other by the polarization splitter 102, and travels in a different direction at a predetermined angle. Next, the first focusing optical system 103 having a positive power condenses these light beams B2 and B3 into point images. Here, it is desirable to make the branch point of the light beams B2 and B3 formed in the polarization branching element 102 coincide with the focal plane of the first focusing optical system 103 as much as possible. By doing so, the two principal rays of the light beams B2 and B3 after passing through the first focusing optical system 103 become parallel.

  An input / output slit 141 of the spectroscope 104 is installed at this point image position. A super continuum light source or a laser light source can collect light in a substantially point-like manner, so that the input / output slit 141 is not necessary, but extra light can be prevented from entering the spectroscope 104. Better. The spectrometer 104 is a wavelength dispersion type. In the example shown in FIG. 2, the grating is a wavelength dispersion element 143, and a collimator 142 and a camera optical system 144 are provided. A wavelength dispersion element such as a prism can be used as appropriate instead of the grating.

  The spectrometer 104 wavelength-resolves two point images on the opening surface of the input / output slit 141 to form two spectrum images of the light source. The two spectrum images have two linear lines arranged in parallel. A reflective liquid crystal element array device 106 having a two-row array configuration is installed so that one reflective liquid crystal element array corresponds to each linear spectrum image position. The position is determined so that the spectrum image is completely formed and reflected in a predetermined wavelength range on the mirror surface of the mirror in the reflective liquid crystal element provided therein. Therefore, the light beams B2 and B3 are reflected and returned to the inside of the spectrometer 104.

  The optical system of the spectroscope 104 is preferably designed so that the principal rays of the corresponding wavelength component light beams incident on the respective reflective liquid crystal elements are arranged in parallel as much as possible. This can be realized by arranging the branch point of the principal ray of each wavelength of the wavelength dispersion element 143 on the focal plane of the camera optical system 144 or in the vicinity thereof. By doing so, the incident angle conditions to the reflective liquid crystal element arrays 161 and 162 arranged on the plane can be made uniform, and variations in retardation characteristics due to variations in incident angles can be prevented. Moreover, the direction of stray light can be aligned, and the processing of stray light can be facilitated.

  A retardation compensation plate 105 is bonded to the light input / output surface of the reflective liquid crystal element array device 106 as necessary. The retardation compensator 105 has an initial retardation slightly left in the liquid crystal element, and a retardation that may be generated due to the optical system between the polarization splitting element 102 and the reflective liquid crystal element array device 106. Used to offset. At this time, the reflected light on the adhesive surface may become stray light, so care should be taken to keep it below a predetermined value. If necessary, an antireflection film is also applied to the adhesive surface.

  Normally, it is sufficient to prepare one retardation compensator 105 for the two reflective liquid crystal element arrays 161 and 162, but if necessary, two retarders optimized for each of the two linearly polarized light beam paths. It is also possible to prepare a foundation compensator and paste each on a corresponding reflective liquid crystal element array.

  When the spectroscopic light beam is reflected from the reflective liquid crystal element array device 106, retardation is generated according to the voltage applied independently to each liquid crystal element. Therefore, the polarization state after reflection of the reflective liquid crystal element array device 106 is generally elliptically polarized light. The reflective liquid crystal element array device 106 generates a predetermined retardation independently for each wavelength element and elliptically polarizes it to generate a spectral attenuation effect when re-passing through the polarization splitting element 102, thereby generating output light. On the other hand, a desired spectrum characteristic is given.

  Note that the polarization state difference between the light beams B2 and B3 is greatly different both when entering the wavelength dispersion element 143 and when entering the wavelength dispersion element 143 after being reflected by the reflective liquid crystal element array device 106. The spectral transmission characteristic (or spectral reflection characteristic) of the wavelength dispersive element 143 usually has polarization dependence, but it appears particularly in the case of a grating. When it is desired to eliminate the spectral characteristic polarization dependency of the wavelength dispersion element 143, the polarization branching when the light beams B4 and B5 re-pass the polarization branching element 102 so that the spectral characteristic polarization dependency of the wavelength dispersion element 143 is canceled. What is necessary is just to give a difference in the amount of spectral attenuation by the element 102. This is realized by adding retardation amounts different by a predetermined amount as a function of wavelength between the reflective liquid crystal element arrays 161 and 162 to the light beams B4 and B5.

  As shown in FIG. 2, a control unit 13 described later is connected to the reflective liquid crystal element array device 106. The control unit 13 controls the voltage applied to each liquid crystal element. Although not shown, the control signal to the control unit 13 is given from a control device such as an external personal computer.

  The light beam reflected by the reflective liquid crystal element array device 106 is subjected to wavelength multiplexing while returning to the spectroscope 104, and returns to the two white light beams B4 and B5. Then, the light is condensed on the input / output slit 141 at the same position as that at the time of input.

  Of the plane including the straight line connecting the centers of the two spots formed on the opening of the input / output slit 141, the plane is orthogonal to the plane including the two principal rays of the light beam (condensed light beam) condensed on the two spots. This plane is called the input / output slit surface. When the chief rays of the light beams B2 and B3 are incident on the respective spots of the input / output slit 141, the chief rays have an angle greater than the condensing NA of the condensed light flux with respect to the normal of the input / output slit surface. The incident angles of the principal rays of the light beams B2 and B3 are tilted so that the light is incident. By doing so, the light beams B2 and B3 from the input / output slit 141 to the reflective liquid crystal element array device 106 and the output light beams B4 and B5 returning to the input / output slit 141 after being reflected by the reflective liquid crystal element array device 106 are input. They are separated except in the vicinity of the output slit 141 and in the vicinity of the reflection point of the reflective liquid crystal element array device 106. This is apparent from the fact that the input / output slit 141 and the reflective surface of the reflective liquid crystal element device 106 are conjugated.

  In addition, it is desirable that the light beam passing through the liquid crystal element does not have an angular distribution. In this case, it is preferable that the incident light beam and the reflected light beam do not form an angle. In addition, by suppressing as much as possible, the adverse effect of the light angle distribution can be reduced.

  The light beam output from the input / output slit 141 of the spectroscope 104 is collimated by the first focusing optical system 103 and then returns to the polarization splitting element 102.

  As described above, by adjusting the focal plane of the first focusing optical system 103 to the polarization branching point of the polarization branching element 102, the principal rays of the two light beams B2 and B3 incident on the input / output slit 141 of the spectroscope 104 are parallel to each other. Thus, the principal rays of the two light beams B4 and B5 emitted from the input / output slit 141 are also parallel to each other. At the same time that the collimating action is received by the first focusing optical system 103, the two light beams B4 and B5 intersect in the polarization splitting element 102. At this time, as described above, since the light beams B2 and B3 and the light beams B4 and B5 are separated, the positions where the light beams B4 and B5 are incident on the polarization branching element 102 are the positions where the light beams B2 and B3 are incident. It will be in a different position.

  The two white light beams B4 and B5 that have returned to the polarization branching element 102 are first deflected in a direction parallel to the direction in which the light beam B1 emitted from the light source unit 101 first enters the polarization branching element 102 by the polarization component. It is divided into a deflection component and a second deflection component and a third deflection component deflected in other directions.

  As the first deflection component, the components of the two white light beams that have returned are almost overlapped, and the light comes out of the polarization splitting element 102 as approximately one light beam. This is called an output light beam B8. The second deflection component light and the third deflection polarization component light travel in two different directions after passing through the polarization splitting element. These are referred to as discarded light beams B6 and B7.

  At this time, as described above, the positions at which the light beams B4 and B5 are incident on the polarization branching element 102 are different from the positions at which the light beams B2 and B3 are incident. Therefore, the output light beam B8 that has passed through the polarization branching element 102 is Direct return to the light source unit 101 is avoided, and the operation of the light source unit 101 does not become unstable.

  A second focusing optical system 108 having a positive power is installed next to the polarization splitting element 102 along the optical path, and in particular, the output light beam B8 is condensed. The discarded light beams B6 and B7 may or may not be incident on the second focusing optical system 108. A pinhole 109 is installed at the condensing point of the output light beam B8, and only the output light beam B8 is allowed to pass therethrough to obtain a light beam having a desired spectrum.

  Instead of providing the second focusing optical system 108 and the pinhole 109, an opening that allows only the output light beam B8 to pass therethrough may be provided. In this case, as compared with the case where the second focusing optical system 108 and the pinhole 109 are provided, it is inevitable that some stray light is mixed in the extracted light beam. Even in the configuration, a light beam having a desired spectrum can be obtained.

  Again, description of the shape measuring apparatus 1 is continued with reference to FIG. The illumination optical system 24 has a positive power. Further, the illumination optical system 24 is arranged so that its focal position coincides with the diffusing element 23.

  The two-dimensional chart 3 is illuminated by the spectrum light source 2. The two-dimensional chart 3 is arranged at the focal position of the illumination optical system 24 opposite to the side where the diffusing element 23 is arranged and at the focal position of the collimator 4 described later. With reference to FIG. 3, the pattern which the two-dimensional chart 3 has is demonstrated. FIG. 3 shows a plan view when the two-dimensional chart 3 is viewed along the optical axis Ax of the shape measuring apparatus 1.

  In the two-dimensional chart 3, as shown in FIG. 3, pinholes 3A are two-dimensionally arranged. In the two-dimensional chart 3, the two-dimensional pattern by the pinhole 3A is repeated along two directions orthogonal to the optical axis Ax and orthogonal to each other. The pinhole 3A functions as a transmission region that transmits light.

  Again, description of the shape measuring apparatus 1 is continued with reference to FIG. The collimator 4 collimates the illumination light L that has passed through the transmission region of the two-dimensional chart 3 to produce a parallel light beam. As shown in FIG. 1, the collimator 4 has a positive power. The collimator 4 is designed to sufficiently remove both axial chromatic aberration and lateral chromatic aberration (focal length chromatic aberration).

  The polarization beam splitter 5 transmits the P-polarized component (or S-polarized component) of the illumination light L and reflects the S-polarized component (P-polarized component). Thereby, the illumination light L reflected by the polarization beam splitter 5 is linearly polarized. The polarization beam splitter 5 deflects the optical path of the illumination light L by approximately 90 ° by reflection. The polarization beam splitter 5 transmits light having a predetermined linearly polarized light component among the light L that has been scattered by the measurement object S described later and then passed through the quarter wavelength plate 6 described later.

  The quarter wavelength plate 6 converts the illumination light L whose optical path is deflected by the polarization beam splitter 5 into circularly polarized light. The quarter wavelength plate 6 converts predetermined polarization component light in the scattered light L from the measurement object S to be described later into linearly polarized light. At this time, the polarization plane of the component light is rotated by 90 ° about the optical axis Ax with respect to the polarization plane of the illumination light L reflected by the polarization beam splitter 5, and thus passes through the polarization beam splitter 5.

The objective optical system 7 collimates a part of the light of the image of the two-dimensional chart 3 projected on the measurement object S and is scattered (including reflection) by the measurement object S and enters the quarter-wave plate 6. Let That is, the objective optical system 7 projects the image of the two-dimensional chart 3 illuminated by the light L output from the spectrum light source 2 onto the measurement object S. The objective optical system 7 projects the image of the two-dimensional chart 3 on the measurement object S at different positions in the optical axis Ax direction of the objective optical system 7 according to the wavelength of the illumination light L. Specifically, three wavelengths lambda _1, lambda _0, when considering lambda ₂ light _{(λ 1 <λ 0 <λ} 2), the optical axis Ax direction of the light _{L 1} is the objective optical system 7 of the wavelength lambda ₁ position in focus at F _1, wavelength lambda light L _{0 0} focused at the position F ₀ in the direction of the optical axis Ax of the objective optical system 7, the optical axis of the light L ₂ having a wavelength lambda ₂ is the objective optical system 7 in It focused at the position _{F 2} in Ax direction. Here, the positions F ₁ , F ₀ and F ₂ are close to the spectrum light source 2 in this order.

  The objective optical system 7 is an optical system having a positive power of an infinite conjugate design, and has a predetermined amount of axial chromatic aberration, but is an optical system in which lateral chromatic aberration is sufficiently removed. The objective optical system 7 includes a first objective optical system 31, an aperture stop 32, and a second objective optical system 33. The first objective optical system 31 functions as an axial chromatic aberration generating element that generates a predetermined amount of axial chromatic aberration. The first objective optical system 31 is installed on the focal plane of the second objective optical system 33. In the first objective optical system 31, the power value at the reference wavelength is 0, the power absolute value gradually increases as it deviates from the reference wavelength within a predetermined wavelength band, and the power value fluctuation is monotonous with respect to the wavelength. It is a certain element. As the reference wavelength, for example, a wavelength near the center in each of the first to third wavelength bands WB1 to WB3 used for measurement may be selected.

  The aperture stop 32 is disposed between the first and second objective optical systems 31 and 33. The second objective optical system 33 having a positive power is a chromatic aberration corrected objective optical in which both longitudinal chromatic aberration and lateral chromatic aberration are sufficiently corrected for light within a predetermined wavelength band output from the spectrum light source 2. Functions as a system. As the second objective optical system 33, for example, an ordinary infinitely conjugate microscope objective lens is used. However, in this case, it is necessary that the focal point on the object point side at infinity is outside the optical system and the first objective optical system 31 can be physically installed.

  FIG. 4 shows the configuration of an example of the first objective optical system 31. The first objective optical system 31 includes a plano-concave lens 31A and a plano-convex lens 31B. The front and back of the objective optical system 31 do not matter. The radius of curvature of the concave surface of the plano-concave lens 31A and the radius of curvature of the convex surface of the plano-convex lens 31B are the same. The first objective optical system 31 is a cemented lens in which the concave surface of the plano-concave lens 31A and the convex surface of the plano-convex lens 31B are cemented.

Plano-concave lens 31A and the plano-convex lens 31 B is the refractive index at the reference wavelength is substantially equal, dispersion values are formed by the different media. Therefore, the first objective optical system 31, which is a cemented lens of the plano-concave lens 31A and the plano-convex lens 31B, functions as a simple plane-parallel plate with respect to the reference wavelength, but is slightly power for wavelengths other than the reference wavelength. It functions as an optical system having Therefore, the light that has passed through the first objective optical system 31 exits the first objective optical system 31 at different angles depending on the wavelength, and as a result, the first objective optical system 31 generates axial chromatic aberration.

  Again, description of the shape measuring apparatus 1 is continued with reference to FIG. Scattered light that has passed through the polarization beam splitter 5 enters the imaging optical system 8. An image of the measurement object S is formed by the imaging optical system 8. The imaging optical system 8 is designed to sufficiently remove both axial chromatic aberration and lateral chromatic aberration (focal length chromatic aberration).

  The wavelength band splitting prism 9 has the same number of wavelength bands WB1, WB2, WB3 output from the spectrum light source 2 as the projected image of the two-dimensional chart 3 scattered by the measurement object S and passed through the imaging optical system 8. Branch based on. The wavelength band branching prism 9 according to the present embodiment is a three-branch type that branches the projection image of the two-dimensional chart 3 that has passed through the imaging optical system 8 into three. As the wavelength band branching prism 9, for example, an RGB three-color separation prism used in a three-plate camera can be used.

  The wavelength band branching prism 9 transmits light having a wavelength corresponding to the first wavelength band WB1 to the first imaging device 10, and light having a wavelength corresponding to the second wavelength band WB2 to the second imaging device 11. The light of the wavelength corresponding to the third wavelength band WB3 is incident on the third imaging device 12, respectively.

  Each of the first to third imaging devices 10 to 12 captures a projected image of the two-dimensional chart 3 branched by the wavelength band branching prism 9. Each of the first to third imaging devices 10 to 12 projects the imaged two-dimensional chart 3 corresponding to the wavelength of the output light from the spectrum light source 2 when the projection image of the two-dimensional chart 3 is obtained. The image is stored as chart data in a storage area of the control unit 13 described later. As the 1st-3rd imaging devices 10-12, a CCD camera, a CMOS camera, etc. can be used, for example.

  The control unit 13 includes a control unit 13A and an analysis unit 13B. The controller 13A controls the voltage applied to the light source device 21 and controls the wavelength of light output from the spectrum light source 2.

  The analysis unit 13B calculates the three-dimensional shape of the measurement object S based on the chart data stored in the first to third imaging devices 10 to 12 and the amount of axial chromatic aberration of the known objective optical system 7.

  Next, a method for measuring the three-dimensional shape of the measurement object S using the shape measuring apparatus 1 will be described. Light having a partial wavelength band (spectrum) that is part of the first wavelength band WB1 from the spectrum light source 2, light having a partial wavelength band (spectrum) that is part of the second wavelength band WB2, and Light having a partial wavelength band (spectrum) that is a part of the third wavelength band WB3 is simultaneously output as illumination light L. The illumination light L illuminates the surface on which the pinholes 3A of the two-dimensional chart 3 are repeatedly arranged. The illumination light L that has passed through the two-dimensional chart 3 is converted into a parallel light beam by the collimator 4. A part of the illumination light L that has become a parallel light beam (P-polarized component or S-polarized component) is reflected by the polarizing beam splitter 5, and the remaining light (S-polarized component or P-polarized component) is transmitted through the polarized beam splitter 5. . The light L reflected by the polarization beam splitter 5 passes through the quarter wavelength plate 6. The light L is linearly polarized light before passing through the quarter-wave plate 6, but is converted into circularly polarized light after passing. The light L that has passed through the quarter-wave plate 6 passes through the first objective optical system 31, the aperture stop 32, and the second objective optical system 33, and is focused on the surface of the measurement object S and its vicinity. To do.

  The light L that has passed through the objective optical system 7 is sufficiently removed from the lateral chromatic aberration, while generating a predetermined amount of axial chromatic aberration. With reference to FIG. 5, the axial chromatic aberration and the lateral chromatic aberration of the objective optical system 7 will be described. FIG. 5 is a diagram for schematically explaining the longitudinal chromatic aberration and the lateral chromatic aberration of the objective optical system 7. In FIG. 5, the structure of the optical system is expressed by a thin lens system. FIG. 5 shows a case where a parallel light beam enters from the spectrum light source 2 side, that is, the first objective optical system 31 side.

5, the reference wavelength light L ₀ is shown in solid lines. Since the first objective optical system 31 has no power at the reference wavelength, the light beam passes through without being refracted and passes through the second objective optical system 33 and is condensed at the focal position F ₀ . On the other hand, the wavelength rays L ₁ and L ₂ around the reference wavelength are indicated by broken lines. The first objective optical system 31 has a slight but positive or negative power with respect to the light beams L ₁ and L _{2 having} wavelengths other than the reference wavelength. Therefore, these wavelength rays L ₁ and L ₂ are condensed or diverged by the first objective optical system 31. Then, after entering the second objective optical system 33, the light is condensed at different positions F ₁ and F ₂ on the optical axis Ax as compared with the case of the reference wavelength light beam L ₀ . That is, it shows axial chromatic aberration.

Here, since the first objective optical system 31 is located on the focal plane (focal length f) of the second objective optical system 33, the first objective optical system 31 is separated from one point on the exit plane of the first objective optical system 31. The emitted light beams L ₀ , L ₁ and L ₂ having different wavelengths travel in parallel with each other after passing through the second objective optical system 32. Therefore, light rays _{L 0,} L 1, the position is a focal point on _{L 2} of the optical axis _{Ax F 0, F 1, F} 2 are different, the angle formed between the optical axis Ax of the three light beams _L 0, L ₁ and L ₂ have the same angle θ.

The three light beams L ₀ , L ₁ , and L ₂ are the same light rays parallel to the optical axis Ax until they enter the first objective optical system 31. Therefore, from the definition of the focal length, the focal length of the objective optical system 7 is the same for all the light beams L ₀ , L ₁ and L _{2 of the} three wavelengths. Therefore, if the minute chromatic aberration remaining in the second objective optical system 32 is ignored, it can be considered that the lateral chromatic aberration of the objective optical system 7 does not exist.

Thus, since the light L that has passed through the objective optical system 7 exhibits axial chromatic aberration as described above, the light L is focused on different positions (for example, positions F ₀ , F ₁ , F _2, etc.) along the optical axis Ax. The light L that has passed through the objective optical system 7 projects an image of the two-dimensional chart 3 onto the measurement object S. The image of the two-dimensional chart 3 projected on the measurement object S also varies in focus depending on the wavelength of the light that projects the image. That is, when an image of the two-dimensional chart 3 projected on an arbitrary position on the surface of the measurement object S is considered, the image of the two-dimensional chart 3 according to the height (unevenness amount) in the optical axis Ax direction at the position. However, the wavelength when focusing on the surface of the measurement object S is different.

Furthermore, with reference to FIG. 6, it shows that the focus position of the image of the two-dimensional chart 3 projected on the to-be-measured body S changes with wavelengths. As shown in FIG. 6, the light having the wavelength λ ₁ is focused on the position S ₁ on the measurement object S. Light having a wavelength λ ₀ is focused on a position S ₂ on the measurement object S. The light having the wavelength λ ₂ is focused on the position S ₃ on the measurement object S.

  Here, the light L for projecting the image of the two-dimensional chart 3 onto the measurement object S is that the principal ray is parallel to the optical axis Ax of the objective optical system 7 regardless of the portion of the projection image, that is, telecentric image projection. It is desirable to do. This is because, by projecting the image of the two-dimensional chart 3 telecentricly onto the measurement object S, for example, even if the height (unevenness) of the measurement object S changes, 2 is projected onto the measurement object S 2. This is because the lateral shift of the image of the dimension chart 3 is suppressed. In order to realize telecentric projection, it is necessary to install the aperture stop 32 on the light source side focal plane of the objective optical system 7 or in the vicinity thereof. On the other hand, as described above, in order to suppress the occurrence of lateral chromatic aberration, the position of the first objective optical system 31 and the light source side focal plane of the second objective optical system 32 are matched in the thin lens representation. Is desirable.

  The image of the two-dimensional chart 3 projected on the measurement object S is scattered by the measurement object S. The light L scattered by the measurement object S passes through the objective optical system 7 and the quarter wavelength plate 6 again. When passing through the quarter-wave plate 6, the polarization plane of the linearly polarized light component in the same direction as the linearly polarized light after passing through the polarizing beam splitter 5 is rotated 90 degrees around the optical axis Ax. Therefore, in this case, the light L is transmitted by the polarization beam splitter 5 without being reflected. That is, the scattered light L from the measurement object S is transmitted through the polarization beam splitter 5 with higher efficiency as the polarization state before the scattering is maintained. The scattered light L that has passed through the polarizing beam splitter 5 enters the imaging optical system 8, and an image of the measurement object S is formed by the imaging optical system 8.

  The image of the measurement object S formed by the imaging optical system 8 is picked up by any of the first to third image pickup devices 10-12. Then, the captured projection image of the two-dimensional chart 3 is stored as chart data in the storage area of the control unit 13 in correspondence with the wavelength of the output light from the spectrum light source 2 when this projection image is obtained.

  The stored chart data is processed by the analysis unit 13B of the control unit 13 based on the chromatic aberration amount of the objective optical system 7. Then, the analysis unit 13B of the control unit 13 calculates the three-dimensional shape of the measurement object S.

  The principle that the analysis unit 13B of the shape measuring apparatus 1 according to this embodiment calculates the three-dimensional shape of the measurement object S will be described below. For example, the width of the partial wavelength band (spectrum) of the illumination light L of the first to third wavelength bands WB1, WB2, and WB3 output from the spectrum light source 2 is limited to a certain width, and the first is maintained while keeping the width constant. Move the partial wavelength band within the third wavelength band WB1, WB2, WB3, that is, increase or decrease the wavelength. And the image of the to-be-measured body S is imaged with the 1st-3rd imaging devices 10-12, changing the wavelength of the illumination light L output from the spectrum light source 2. FIG. Since the height (unevenness amount) of the surface of the measurement object S and the wavelength of the illumination light L focused at that height correspond one-to-one, the measurement object S according to the height of the measurement object S. The wavelength that focuses on the surface is uniquely determined. Based on these principles, the analysis unit 13B of the control unit 13 performs image analysis on the acquired chart data.

  With reference to FIGS. 7 and 8, the relationship between the intensity (pinhole image intensity) of the image (pinhole image intensity) of the two-dimensional chart 3 imaged by the imaging device and the wavelength of the light output from the spectrum light source 2 is shown. explain. FIG. 7 shows the pinhole image intensity as a function of wavelength. FIG. 8 shows the contrast between the background and the peak value when the scattered light of the image of the two-dimensional chart 3 projected on the measurement object S, that is, the contrast between the background and the peak value of the pinhole image intensity. Is shown as a function of wavelength.

  FIG. 7 shows a case where a plurality of images of the two-dimensional chart 3 in a partial wavelength band having a predetermined width are sampled at appropriate wavelength intervals. As can be seen from FIG. 7, in the sampled five partial wavelength bands dλ1 to dλ5, the pinhole image intensity has a peak value Ip at the center of the pinhole image. Further, the sampled five partial wavelength bands dλ1 to dλ5 have a background value Iv of the pinhole image intensity.

  FIG. 8 shows the contrast between the peak value Ip and the background value Iv as a function of wavelength for the pinhole image intensities in the five sampled partial wavelength bands dλ1 to dλ5. The wavelength λp at which the contrast in FIG. 8 shows a peak, that is, the wavelength λp having the maximum difference between the peak value Ip and the background value Iv is regarded as the focus wavelength. Then, from the correspondence between the focusing wavelength λp and the axial chromatic aberration of the objective optical system 7, the height (unevenness amount) of the corresponding part of the measurement object S in the optical axis Ax direction is calculated.

  The analysis unit 13B of the control unit 13 holds, for example, the graphs of FIGS. 7 and 8 as a result of the image analysis, and can calculate the three-dimensional shape of the surface of the measurement object S based on the above-described principle. The analysis unit 13B may calculate the height of each part in a two-dimensional manner on the measured object S and output the calculated data to the two-dimensional map as the surface shape of the measured object S.

  Thus, the analysis unit 13B of the control unit 13 can function as an imaging data processing unit that calculates the three-dimensional shape of the measurement object S based on the stored chart data and the chromatic aberration amount of the objective optical system 7. . In other words, the analysis unit 13B of the control unit 13 is at an arbitrary position on the measured object S based on the relationship between the wavelength of the illumination light L output from the spectrum light source 2 and the intensity of the projected image of the two-dimensional chart 3. And the height (unevenness) of the objective optical system 7 in the optical axis Ax direction at an arbitrary position on the measured object S is calculated from the amount of chromatic aberration of the objective optical system 7 for the focused wavelength. Thus, the three-dimensional shape of the measurement object S is measured.

  Here, with reference to FIG. 9, the relationship between the wavelength band branching by the wavelength band branching prism 9 and the first to third wavelength bands of the illumination light will be described. In each of the graphs shown in FIGS. 9A to 9C, the horizontal axis represents the wavelength, and the vertical axis represents the transmittance. The curves in the first to third wavelength bands WB1, WB2, and WB3 in FIGS. 9A to 9C represent the wavelength bands after being branched into three, respectively, and these are the first imaging device 10. Images are taken by the second imaging device 11 and the third imaging device 12. As shown in FIG. 9A, the spectrum light source 2 outputs light in a partial wavelength band included as a part of each of the wavelength bands WB1 to WB3. A partial wavelength band changes a wavelength band in the range which does not leave the inside of corresponding wavelength band WB1-WB3. Imaging of the image of the two-dimensional chart 3 is performed every predetermined wavelength change.

  Further, as shown in FIG. 9B, the crossover region (overlapping wavelength region) between adjacent wavelength bands, that is, the crossover region CB1 of the first and second wavelength bands WB1 and WB2, and the second and third When outputting light having a wavelength within the crossover region CB2 of the wavelength bands WB2 and WB3, the number of wavelength bands to be actually output is one less than the number of wavelength bands that can be output by the spectrum light source 2 (2 in this embodiment). Reduced to 2). As a result, the situation where two output partial wavelength bands exist in one wavelength band as shown in FIG. 9C is suppressed.

  The shape measuring apparatus 1 includes a spectrum light source 2 that can output light of a plurality of wavelengths in the first to third wavelength bands WB1 to WB3. The objective optical system 7 can generate predetermined axial chromatic aberration. Therefore, in the shape measuring apparatus 1, it is possible to measure the height (unevenness amount) in the optical axis Ax direction at an arbitrary position of the measurement object S in a non-contact manner using the longitudinal chromatic aberration.

  In general, a method for measuring the three-dimensional shape of an object to be measured using an interference method, moire topography, a pattern projection method, or the like is known. In these methods, the phase change is read from the deformation of the striped pattern that appears on the surface of the measurement object S, and the surface shape is calculated by converting the phase change into surface irregularities. In these methods, when the unevenness of the measurement object has a depth exceeding one phase of the phase of the measurement pattern, a wrapping phenomenon occurs in which the measured phase is folded by 2π units. For this reason, it is necessary to perform an unwrapping process for extending the wrapping, which is the folding of the phase, and returning it to the correct unevenness amount. On the other hand, since the shape measuring apparatus 1 measures the shape of the measurement object S using axial chromatic aberration, the unwrapping process is not necessary.

  Further, in the shape measuring apparatus 1, information of a predetermined range on the surface of the measurement object S is measured at a time by capturing an image of the two-dimensional chart 3 in which a pattern is arranged two-dimensionally by the imaging apparatuses 10 to 12. be able to. That is, the three-dimensional shape of the measurement object S can be measured without mechanical movement in the apparatus. In this way, since the measurement is performed using the chart 3 and the imaging devices 10 to 12 that act two-dimensionally, an image scanning mechanism for acquiring two-dimensional data becomes unnecessary, and the device can be simplified.

  Furthermore, with the simplification of the apparatus, the shape measuring apparatus 1 can suppress the vibration of the apparatus, reduce the cost, stabilize the operation of the apparatus, and the like.

  Further, in the shape measuring apparatus 1, the spectrum light source 2 outputs three partial wavelength bands at the same time while changing the partial wavelength bands output in the three wavelength bands of the first to third wavelength bands WB1, WB2, and WB3. ing. Moreover, the shape measuring apparatus 1 divides the wavelength range to be measured using the wavelength band branching prism 9 into three, and the first to third imaging apparatuses 10 to 12 in parallel for each divided wavelength band. Imaged. That is, in the first to third wavelength bands WB1, WB2, and WB3, the change of the partial wavelength band to be output and the imaging of the image of the two-dimensional chart 3 are performed in parallel. Thereby, it becomes possible to acquire necessary data in a short time compared to a case where the entire first to third wavelength bands WB1, WB2, and WB3 are imaged without branching the wavelength bands.

Furthermore, the range of the height (unevenness amount) of the measured object S in the optical axis Ax direction can be freely set by selecting the axial chromatic aberration amount of the objective optical system 7 and the wavelength range of the light output from the light source. it can. Therefore, the shape can be measured for a wide range of measurement objects.
(Second Embodiment)

  With reference to FIG. 10, the structure of the shape measuring apparatus 41 which concerns on 2nd Embodiment is demonstrated. The shape measuring device 41 according to the second embodiment is different from the shape measuring device 1 according to the first embodiment in that the illumination light is incident obliquely with respect to the two-dimensional chart. FIG. 10 is a configuration diagram of a shape measuring apparatus according to the second embodiment.

  10 includes a spectrum light source 2, a two-dimensional chart 42, a collimator 4, a plane mirror 43, an objective optical system (projection optical system) 44, an imaging optical system 8, and a wavelength band. A branching prism (branching unit) 9, a first imaging device 10, a second imaging device 11, a third imaging device 12, and a control unit 13 are provided.

  The two-dimensional chart 42 is illuminated by the spectrum light source 2. FIG. 11 is a plan view when the two-dimensional chart 42 is viewed along the optical axis Ax of the shape measuring device 41. As shown in FIG. 11, the two-dimensional chart 42 is formed with a striped pattern in which striped slits 42 </ b> A are arranged along a predetermined direction. The slit 42A functions as a transmission region that transmits light.

  The two-dimensional chart 42 is arranged so that the longitudinal direction of the image of the slit 42A formed on the measurement object S in FIG. 10 is a direction orthogonal to the paper surface of FIG.

  In the shape measuring device 41, as shown in FIG. 10, the two-dimensional chart 42 is illuminated obliquely so as to have a non-rotationally symmetric light intensity distribution with respect to the optical axis Ax of the measuring device 41. The plane mirror 12 causes the light that passes through the two-dimensional chart 42 and projects the image of the chart 42 to reach the objective optical system 44.

  The objective optical system 44 includes a first objective optical system 51, a projection light partial aperture stop 52, an imaging light partial aperture stop 53, and a second objective optical system 54. The first objective optical system 51 functions as an axial chromatic aberration generating element that generates a predetermined amount of axial chromatic aberration. The partial aperture stop 52 for projection light includes the optical axis Ax of the objective optical system 44, and when the aperture stop surface is divided into two parts by a plane perpendicular to the paper surface of FIG. It is installed at a position that allows the projection light to pass efficiently. As a result, the measurement object S is illuminated obliquely.

  The second objective optical system 54 functions as a chromatic aberration-corrected objective optical system in which both axial chromatic aberration and lateral chromatic aberration are sufficiently corrected with respect to light within a predetermined wavelength band output from the spectrum light source 2. The imaging light partial aperture stop 53 is disposed on the same plane as and adjacent to the projection light partial aperture stop 52. The imaging light partial aperture stop 53 allows part of the reflected light and scattered light from the measurement object S returned to the objective optical system 44 to pass therethrough. Then, only the component light that has passed through the imaging light partial aperture stop 53 enters the imaging optical system 8. The projection light partial aperture stop 52 and the imaging light partial aperture stop 53 are not necessarily located at the illustrated positions, and may be installed at a place where an equivalent effect can be obtained.

  In the shape measuring device 41, the objective optical system 44 has a projection light partial aperture stop 52 and an imaging light partial aperture stop 53 arranged adjacent to each other, and the projection light L before entering the measurement object S is It passes only through the projection light partial aperture stop 52. That is, the objective optical system 44 emits the output light from the spectrum light source 2 only from one of the regions (region corresponding to the projection light partial aperture stop 52) when the region is divided into two. Has a pupil shape.

  In addition, the analysis unit 13B of the control unit 13 detects a change in the center of gravity position in a predetermined plurality of regions of the chart data obtained in the imaging devices 10 to 12, and compares it with the longitudinal chromatic aberration characteristic of the objective optical system 44. The amount of unevenness in the optical axis Ax direction of the objective optical system 44 at the position of the measurement object S corresponding to each of the plurality of regions is calculated.

  In the shape measuring device 41, since the illumination light is incident obliquely with respect to the two-dimensional chart using the two-dimensional chart 42 having the repetition of the slit pattern, the distortion amount of the image of the slit 42A of the two-dimensional chart 42 for each wavelength. And the amount of blur are calculated and compared with the longitudinal chromatic aberration of the objective optical system 44, thereby obtaining the height (unevenness amount) of the measured object S in the optical axis Ax direction.

  As shown in FIG. 12, in the pattern image (slit image) of the two-dimensional chart 42 formed on the measurement object S, the light intensity distribution cross section at an arbitrary position X0 changes according to the wavelength of the illumination light L. To do. 12A to 12E, the illumination that forms an image of the two-dimensional chart 42 with respect to the cross-sectional shape of the measurement object S at an arbitrary position X0 when the wavelength of the illumination light L is different. The imaging position of the light L is shown. FIG. 12A to FIG. 12E correspond to the case where the wavelength increases or decreases in this order. FIG. 12C shows a state in which the illumination light forming the image of the two-dimensional chart 42 is focused at an arbitrary position X0. 12A to 12E, the horizontal axis indicates the position on the measurement object S, and the vertical axis indicates the height (unevenness).

  FIG. 13 shows the light intensity distribution of the slit image imaged by the imaging device. 13 (a) to 13 (e) correspond to FIGS. 12 (a) to 12 (e), respectively. That is, FIG. 13A to FIG. 13E show the light condensing when the two-dimensional chart 42 is illuminated with the illumination light L having the wavelength corresponding to FIG. 12A to FIG. Represents a state. 13A to 13E, the horizontal axis indicates the position on the measurement object S, and the vertical axis indicates the slit image light intensity distribution.

  As understood from FIG. 13, the peak position of the slit image light intensity distribution moves in the X-axis direction in accordance with the wavelength change of the illumination light L. When the peak of the intensity distribution coincides with the position X0, that is, FIG. 13C is in a focused state. The analysis unit 13B of the control unit 13 calculates the wavelength of the illumination light focused at an arbitrary position X0 of the measurement object S from the relationship between the X coordinate value of the peak of the intensity distribution and the wavelength of the illumination light L, and the objective In light of the axial chromatic aberration of the optical system 44, the height (unevenness amount) of the target portion X0 of the measurement object S is obtained. Then, once the height of each part on the measurement object S is two-dimensionally calculated by the analysis unit 13B of the control unit 13, the data is used as the surface shape of the measurement object S and a two-dimensional map is obtained. Output.

Referring to FIG. 14, it is shown that the in-focus position of the image of the two-dimensional chart 42 projected on the measurement object S changes depending on the wavelength. As shown in FIG. 14, the light having the wavelength λ ₁ is focused on the position S ₁ on the measurement object S. Light having a wavelength λ ₀ is focused on a position S ₂ on the measurement object S. The light having the wavelength λ ₂ is focused on the position S ₃ on the measurement object S.

  In the shape measuring device 41, the projection light partial aperture stop 52 is arranged at an eccentric position not including the optical axis Ax of the objective optical system 44. Therefore, when it is assumed that light is incident on all the apertures of the objective optical system 44 as in the shape measuring apparatus 1 according to the first embodiment, the object to be measured S is telecentric as in the first embodiment. As shown in FIG. 14, even if the image of the two-dimensional chart 42 is projected obliquely onto the measurement object S, the height of the measurement object S is set by setting so that the appropriate projection light is incident. The lateral shift of the projected image due to the change of is difficult to occur.

  The shape measuring device 41 includes a spectrum light source 2 that can output light of a plurality of wavelengths in the first to third wavelength bands WB1 to WB3. The objective optical system 44 can generate a predetermined axial chromatic aberration. Therefore, the shape measuring apparatus 41 can measure the height (unevenness amount) in the optical axis Ax direction at an arbitrary position of the measurement object S in a non-contact manner using axial chromatic aberration.

  In addition, since the shape measuring device 41 measures the shape of the measurement object S using longitudinal chromatic aberration, unwrapping processing is not necessary.

  Further, the shape measuring device 41 measures information of a predetermined range on the surface of the measurement object S at a time by taking an image of the two-dimensional chart 42 in which the pattern is arranged two-dimensionally with the imaging devices 10 to 12. ing. That is, the three-dimensional shape of the measurement object S can be measured without mechanical movement in the apparatus. Therefore, the shape measuring device 41 does not require an image scanning mechanism for obtaining two-dimensional data, and can simplify the device. Furthermore, with the simplification of the apparatus, the shape measuring apparatus 41 can suppress the vibration of the apparatus, reduce the cost, stabilize the operation of the apparatus, and the like.

  In addition, the shape measuring apparatus 41 performs in parallel the change of the partial wavelength band to be output and the imaging of the two-dimensional chart 3 in the first to third wavelength bands WB1, WB2, and WB3. Thereby, it becomes possible to acquire necessary data in a short time compared to a case where the entire first to third wavelength bands WB1, WB2, and WB3 are imaged without branching the wavelength bands.

  Further, in the shape measuring apparatus 41, the range of the height (unevenness amount) of the measured object S in the optical axis Ax direction is selected by selecting the axial chromatic aberration amount of the objective optical system 7 and the wavelength range of the light output from the light source. It can also be set freely. Therefore, the shape can be measured for a wide range of measurement objects.

    As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, the first objective optical systems 31 and 51 that function as axial chromatic aberration generating elements are not limited to the configurations described in FIGS. 1, 4, and 10. Therefore, for example, the first objective optical system 31 may be configured as shown in FIG. In FIG. 15, two first objective optical systems 31, which are cemented lenses of the plano-concave lens 31 </ b> A and the plano-convex lens 31 </ b> B, are prepared and arranged at an appropriate interval. The two first objective optical systems 31 are arranged so that the lenses of the same medium, that is, the plano-convex lenses 31B face each other, and the aperture stop 32 is disposed between the two first objective optical systems 31. Yes.

  Further, the first objective optical system 51 may be configured as shown in FIG. In FIG. 16, two first objective optical systems 51, which are cemented lenses of the plano-concave lens 51A and the plano-convex lens 51B, are prepared instead of one and arranged at an appropriate interval. The two first objective optical systems 51 are arranged so that the lenses of the same medium, that is, the plano-convex lenses 51B face each other, and the projection light partial aperture stop 52 and the imaging light partial aperture stop 53 are arranged in two. It is arranged in the middle of the first objective optical system 31.

  As shown in FIG. 15, when two first objective optical systems 31 and an aperture stop 32 arranged at the center thereof are used, the aperture stop 32 is conjugate with the light source side focal plane of the second objective optical system 32. By being installed in such a manner, it is possible to sufficiently suppress the occurrence of lateral chromatic aberration with a practically sufficient approximation. Further, in this case, it is possible to satisfy the telecentric condition. This is because the absolute value of the power of the first objective optical system 31 is very small.

  As the two-dimensional chart, a chart having a pattern other than the chart 3 shown in the first embodiment and the chart 42 shown in the second embodiment may be used.

  Further, the storage area for storing the chart data is not limited to the control unit 13 and may exist in the imaging apparatus, for example.

It is a block diagram of the shape measuring apparatus which concerns on 1st Embodiment. It is a block diagram of the light source device with which the shape measuring apparatus which concerns on 1st Embodiment is provided. It is a top view when seeing a two-dimensional chart along the optical axis of a shape measuring device. It is a block diagram of the 1st objective optical system with which the shape measuring apparatus which concerns on 1st Embodiment is provided. It is a figure for demonstrating typically about the axial chromatic aberration and magnification chromatic aberration of an objective optical system. It is a figure for demonstrating that the focus position of the image of the two-dimensional chart projected on a to-be-measured body changes with wavelengths. It is a figure which shows the image intensity of the two-dimensional chart in the partial wavelength band which has a predetermined width | variety. It is a figure which shows the contrast of the peak value of pinhole image intensity in the sampled partial wavelength band, and a background value as a function of a wavelength. It is a figure for demonstrating the relationship between the wavelength band branch by a wavelength band branch prism, and the 1st-3rd wavelength band of illumination light. It is a block diagram of the shape measuring apparatus which concerns on 2nd Embodiment. It is a top view when seeing a two-dimensional chart along the optical axis of a shape measuring device. It is a figure showing the image formation state by the wavelength of the image of the two-dimensional chart formed in the arbitrary positions on a to-be-measured body. It is a figure which shows the light intensity distribution of the slit image imaged with the imaging device. It is a figure for demonstrating that the focus position of the image of the two-dimensional chart projected on the to-be-measured body changes with wavelengths. It is a block diagram of the modification of the 1st objective optical system of the shape measuring apparatus which concerns on 1st Embodiment. It is a block diagram of the modification of the 1st objective optical system of the shape measuring apparatus which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,41 ... Shape measuring apparatus, 2 ... Spectrum light source, 3, 42 ... Two-dimensional chart, 4 ... Collimator, 5 ... Polarizing beam splitter, 6 ... 1/4 wavelength plate, 7, 44 ... Objective optical system, 8 ... Connection Image optical system, 9 ... wavelength branching prism, 10 ... first imaging device, 11 ... second imaging device, 12 ... third imaging device, 13 ... control unit, 43 ... planar mirror.

Claims (5)

An apparatus for measuring a three-dimensional shape of a measured object,
A light source capable of outputting light by changing the wavelength in each of a plurality of predetermined wavelength bands;
A two-dimensional chart in which a pattern having a region that transmits light is repeated along a predetermined direction;
A projection optical system having a predetermined amount of chromatic aberration and projecting an image of the two-dimensional chart illuminated by the light output from the light source onto the object to be measured;
The two-dimensional image captured in correspondence with the wavelength of the output light from the light source when the projection image of the two-dimensional chart scattered by the measurement object is captured and the projection image of the two-dimensional chart is obtained An imaging unit for storing a projected image of the chart in a storage area as chart data;
An imaging data processing unit that calculates a three-dimensional shape of the object to be measured based on the chart data stored in the storage region and the amount of chromatic aberration of the projection optical system;
The light source simultaneously outputs light in a partial wavelength band that is a part of the predetermined wavelength band in each of the plurality of predetermined wavelength bands, and each of the predetermined wavelength bands corresponding to the partial wavelength bands of the output light . Output light by changing within the wavelength band,
The imaging unit is provided in the number of the plurality of predetermined wavelength bands so as to correspond to each of the plurality of predetermined wavelength bands,
A branching part for branching the projected image of the chart scattered by the measured object based on the wavelength by the number of the plurality of predetermined wavelength bands;
A three-dimensional shape measuring apparatus that captures a projected image of the chart branched by the branching unit with the corresponding imaging unit .   The imaging data processing unit obtains a focusing wavelength at an arbitrary position on the measured object based on a relationship between a wavelength of light output from the light source and an intensity of a projected image of the two-dimensional chart, The amount of unevenness in the optical axis direction of the projection optical system at the arbitrary position on the measured object is calculated from the amount of chromatic aberration of the projection optical system with respect to the focusing wavelength, and the three-dimensional shape of the measured object is measured. The three-dimensional shape measuring apparatus according to claim 1.   The imaging data processing unit specifies, as the focused wavelength, a wavelength when the difference between the intensity of the projected image of the chart showing a peak in the partial wavelength band and the background intensity in the partial wavelength band is the largest. The three-dimensional shape measuring apparatus according to claim 2. An apparatus for measuring a three-dimensional shape of a measured object,
A light source capable of outputting light by changing the wavelength within a predetermined wavelength band;
A two-dimensional chart in which a pattern having a region that transmits light is repeated along a predetermined direction;
A projection optical system having a predetermined amount of chromatic aberration and projecting an image of the two-dimensional chart illuminated by the light output from the light source onto the object to be measured;
The two-dimensional image captured in correspondence with the wavelength of the output light from the light source when the projection image of the two-dimensional chart scattered by the measurement object is captured and the projection image of the two-dimensional chart is obtained An imaging unit for storing a projected image of the chart in a storage area as chart data;
An imaging data processing unit that calculates a three-dimensional shape of the object to be measured based on the chart data stored in the storage region and the amount of chromatic aberration of the projection optical system;
The projection optical system has an exit pupil that emits output light from the light source only from one of the regions when the region is divided into two,
The imaging data processing unit detects a change in the centroid position in a predetermined plurality of regions of the chart data obtained in the imaging unit, and compares the change in the centroid position with chromatic aberration of the projection optical system. A three-dimensional shape measuring apparatus that measures the three-dimensional shape of the measurement object by calculating the unevenness in the optical axis direction of the projection optical system at the position of the measurement object corresponding to each region.   The three-dimensional shape measuring apparatus according to claim 1, wherein the chromatic aberration of the projection optical system is axial chromatic aberration.

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