Optical measuring device

Abstract

The present application can reduce the measurement error of a rough surface without increasing the depth of field. An optical measurement device includes: a light source that outputs light of a plurality of wavelengths; a first slit member that has a first opening that passes a portion of the light from the light source; an optical system that causes the light that has passed through the first opening to produce chromatic aberration along an optical axis; an objective lens that irradiates the light that has produced chromatic aberration to a measurement target object; a second slit member that has a second opening that passes a portion of reflected light of the light that is irradiated to the measurement target object; a light-receiving optical fiber that propagates the light that has passed through the second opening; and a light-receiving sensor that acquires the propagated light, measures the spectrum of the light, and the first opening and the second opening each have a shape that includes a plurality of pinholes.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an optical measurement device. BACKGROUND

[0002] Conventionally, an optical measurement device is known, which is capable of measuring a surface shape or the like of a measurement target object using a confocal optical system.

[0003] For example, an optical measurement device is described in Patent Literature 1 below, which radiates light emitted from a point light source to a measurement target object, and receives light reflected by the measurement target object via a diaphragm hole (pinhole) by a light receiving element. The optical measurement device is configured to detect that the measurement target object is located at a predetermined position when the light emitted from the point light source is focused on the measurement target object, the position of the diaphragm hole at which the amount of light received by the light receiving element reaches a maximum. Further, an optical measurement device is known, which measures a position of a measurement target object on an optical axis by combining a point light source which outputs a plurality of wavelengths, a chromatic aberration optical system, and a beam splitter in such a confocal optical system.

[0004] [Patent Literature]

[0005] [Patent Literature]

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2010-216873 SUMMARY

[0007] [Problems to be Solved by the Invention]

[0008] Here, in a case where a measurement target object having a rough surface is measured, if the point diameter of light radiated to the measurement target object is increased, the concave-convex of the rough surface is averaged. Therefore, by increasing the point diameter, the measurement error of the rough surface can be reduced.

[0009] However, if the point diameter is increased, the depth of field of the optical measurement device also becomes large (deep). As a result, the performance such as linearity, resolution, or the like of the optical measurement device will be degraded.

[0010] Therefore, an object of the present application is to provide an optical measurement device which does not increase the depth of field and can reduce the measurement error of a rough surface.

[0011] [Means of Solving the Problems]

[0012] The optical measurement device of one embodiment of the present disclosure includes a light source which outputs light of a plurality of wavelengths; a first restriction member which is formed with a first opening through which a part of the light from the light source passes; an optical system which causes the light which has passed through the first opening to produce chromatic aberration along an optical axis; an objective lens which irradiates the light which has produced chromatic aberration to a measurement target object; a second restriction member which is formed with a second opening through which a part of reflected light of the light which is irradiated to the measurement target object passes; an optical fiber which propagates the light which has passed through the second opening; and a light-receiving sensor which acquires the light which has propagated, and measures a spectrum of the light, the first opening and the second opening each have a shape including a plurality of pinholes.

[0013] According to this embodiment, the first opening of the first restriction member has a shape including a plurality of pinholes. Thus, the point diameter in the short diameter direction of the opening is not increased, and a linespot which extends in one direction can be formed on the surface of the measurement target object, so that the depth of field can be maintained without changing. Thus, the decrease in performance such as linearity and resolution can be suppressed. Moreover, the reflected light which has passed through the second opening of the second restriction member is propagated by the optical fiber. Thus, the light which has passed through the second opening is mixed, and the distance information (height information) of the plurality of points which are focused in the one direction in which the linespot extends is integrated, so that the unevenness of the rough surface in the linespot is averaged, and the variation due to the measurement place of the focused wavelength can be suppressed. Thus, the measurement error of the rough surface of the measurement target object can be reduced.

[0014] In the foregoing embodiment, the optical fiber can also be a plastic optical fiber.

[0015] According to this embodiment, the optical fiber is a plastic optical fiber. Thus, compared to other types of optical fibers, the optical fiber with a large core diameter can be produced at a low cost, so that the light from the second opening of the second restriction member can be introduced more, and the unevenness of the rough surface in the linespot can be further averaged.

[0016] In the foregoing embodiment, the light-receiving sensor can also include a plurality of light-receiving elements which are arranged in one dimension.

[0017] According to this embodiment, the light-receiving sensor includes a plurality of light-receiving elements which are arranged in one dimension. Thus, compared to the case where the plurality of light-receiving elements are arranged in two dimensions, the measurement target object can be measured at a low cost.

[0018] In the foregoing embodiment, a third restriction member which is formed with a third opening through which a part of the light which has propagated passes can also be included, and the light-receiving sensor measures a spectrum of the light which has passed through the third opening.

[0019] According to this embodiment, the light receiving sensor measures the spectrum of light passing through the third opening. This allows the third opening to form light of a desired shape. For example, by aligning the direction (longitudinal direction) of the third opening with the longitudinal direction of each light receiving element of the light receiving sensor, the amount of light received by the light receiving element can be increased.

[0020] The aforementioned embodiment may further include a light extinction member disposed on the optical path of the reflected light to suppress light of a wavelength not focused by the second limiting member from being received by the light receiving sensor.

[0021] According to this embodiment, the de-lighting member is arranged on the optical path of the reflected light to prevent light of wavelengths not focused by the second limiting member from being received by the light receiving sensor. This reduces crosstalk and improves measurement accuracy of the object.

[0022] In the aforementioned embodiment, the first opening may also have a linear shape, and the shape of the second opening may also correspond to the shape of the first opening.

[0023] According to this embodiment, the first opening has a linear shape, and the second opening has a shape corresponding to the first opening. This makes it possible to easily form a line point extending in one direction on the surface of the object to be measured.

[0024] The aforementioned embodiment may also include an optical path separation element that separates the optical path of the reflected light from the optical path of the light from the light source, and the second opening is configured to allow a portion of the reflected light separated by the optical path separation element to pass therethrough.

[0025] According to this embodiment, an optical path separation element is further included to separate the optical path of the reflected light from the optical path of the light from the light source. This eliminates the need for, for example, an optical coupler to branch (demultiplex) the reflected light from the light from the light source, thereby preventing the generation of noise light caused by the reflected light from the first opening.

[0026] In the aforementioned embodiment, the first limiting member and the second limiting member may also be the same member.

[0027] According to this embodiment, the first limiting member and the second limiting member are the same member. Thus, a single limiting member is included, and thus the measurement accuracy of the object can be improved at low cost compared to a case where a plurality of limiting members are included.

[0028] The aforementioned embodiment may further include an optical coupler that branches the reflected light from the light from the light source.

[0029] According to this embodiment, a light coupler that branches the reflected light from the light from the light source is also included. Thus, an optical measurement device that can easily reduce the measurement error of the rough surface is included by including the single restriction member.

[0030] In the foregoing embodiment, the light from the light source can also be white light.

[0031] According to this embodiment, the light from the light source is white light. Thus, in the optical system, a chromatic aberration can be easily generated.

[0032] In the foregoing embodiment, the optical measurement device can also be a displacement measurement device that measures the displacement of the measurement object.

[0033] According to this embodiment, the optical measurement device is a displacement measurement device that measures the displacement of the measurement object. Thus, a displacement measurement device that can easily reduce the displacement measurement error of the rough surface of the measurement object is implemented.

[0034] In the foregoing embodiment, the first restriction member can also be formed with a plurality of first openings, and the second restriction member can also be formed with a plurality of second openings.

[0035] According to this embodiment, the second restriction member is formed with a plurality of second openings. Thus, the unevenness of the rough surface within the line point can be further averaged, and by increasing the amount of light passing through the second openings, the measurement of the measurement object can be performed at high speed.

[0036] [Effects of the Invention]

[0037] According to the present invention, the measurement error of the rough surface can be reduced without increasing the depth of field. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a configuration diagram illustrating the outline configuration of the optical measurement device in an embodiment.

[0039] Figure 2 is a summary diagram illustrating the measurement of the measurement object by the optical measurement device in an embodiment.

[0040] Figure 3 is a conceptual diagram for explaining the performance of the optical measurement device in the confocal method.

[0041] Figure 4 is a chart illustrating the light-receiving amount distribution signal of the optical measurement device in the confocal method using a pinhole.

[0042] Figure 5 is a chart illustrating the light-receiving amount distribution signal of the optical measurement device in an embodiment.

[0043] Figure 6Fig. 2 is a plan view illustrating a second slit member of an optical measurement apparatus in an embodiment.

[0044] Figure 7 Fig. 3 is a plan view illustrating a third slit member of an optical measurement apparatus in an embodiment.

[0045] Figure 8 Fig. 4 is a plan view illustrating an end surface of an optical fiber for light reception of an optical measurement apparatus in an embodiment.

[0046] Figure 9 Fig. 5 is a plan view illustrating an extinction member of an optical measurement apparatus in an embodiment.

[0047] Figure 10 Fig. 6 is a configuration view illustrating a schematic configuration of an optical measurement apparatus in a modification example of an embodiment.

[0048] Figure 11 Fig. 7 is a plan view illustrating a first slit member of a first example of an optical measurement apparatus in a second modification example of an embodiment.

[0049] Figure 12 Fig. 8 is a plan view illustrating a first slit member of a second example of an optical measurement apparatus in a second modification example of an embodiment.

[0050] Figure 13 Fig. 9 is a plan view illustrating a first slit member of a third example of an optical measurement apparatus in a second modification example of an embodiment.

[0051] Figure 14 Fig. 10 is a plan view illustrating a first slit member of a fourth example of an optical measurement apparatus in a second modification example of an embodiment.

[0052] [Explanation of Symbols]

[0053] 10: Light source

[0054] 11: Optical fiber for light projection

[0055] 20: Sensor head

[0056] 21, 21A, 21B, 21C, 21D: First slit member

[0057] 21a, 21b, 21c, 21d, 21e: First opening

[0058] 22: Half mirror

[0059] 23: Diffractive lens

[0060] 24: Objective lens

[0061] 25: Extinction member

[0062] 26, 26A, 26B, 26C, 26D: second slit member

[0063] 26a, 26b, 26c, 26d, 26e: second opening

[0064] 27: light-receiving optical fiber

[0065] 27a: optical fiber diameter

[0066] 27b: core diameter

[0067] 30: optical splitter

[0068] 31: third slit member

[0069] 31a: third opening

[0070] 32: first lens

[0071] 33: diffraction grating

[0072] 34: second lens

[0073] 35: light-receiving sensor

[0074] 36: processing circuitry

[0075] 40: optical coupler

[0076] 41: light-emitting / receiving optical fiber

[0077] 90: controller

[0078] 100, 100A: optical measurement device

[0079] AX: optical axis

[0080] BS: surface

[0081] DS: diffraction surface

[0082] TA: measurement target object DETAILED DESCRIPTION

[0083] Embodiments of the present application will be described below. In the following description of the drawings, the same or similar parts are designated by the same or similar signs. However, the drawings are schematic. Thus, specific dimensions and the like should be judged in light of the following description. Also, the drawings naturally include parts different from each other in size relationship or ratio among each other. Furthermore, the technical scope of the present application should not be construed as being limited to the embodiments described below.

[0084] First, the structure of an optical measurement device according to an embodiment will be described with reference to Figure 1 Figure 1 is a structural view illustrating the schematic structure of an optical measurement device 100 according to an embodiment.​

[0085] like Figure 1 As shown, the optical measurement device 100 includes, for example, a light source 10, a light-projecting optical fiber 11, a first slit member 21, a half mirror 22, a diffraction lens 23, an objective lens 24, a light-extinguishing member 25, a second slit member 26, a light-receiving optical fiber 27, and a spectrometer 30. The first slit member 21 of this embodiment corresponds to an example of a "first limiting member," the half mirror 22 of this embodiment corresponds to an example of an "optical path separation element," the diffraction lens 23 of this embodiment corresponds to an example of an "optical system," and the second slit member 26 of this embodiment corresponds to an example of a "second limiting member."

[0086] A portion of the projecting optical fiber 11, the first slit member 21, the half mirror 22, the diffraction lens 23, the objective lens 24, the light extinction member 25, the second slit member 26, and a portion of the receiving optical fiber 27 are housed or mounted in the sensor head 20. Meanwhile, the light source 10, a portion of the projecting optical fiber 11, a portion of the receiving optical fiber 27, and the spectrometer 30 are housed or mounted in the controller 90.

[0087] However, the components of the optical measurement device 100 are not limited to being divided into the sensor head 20 and the controller 90. For example, the components of the optical measurement device 100 may be divided into three or more components.

[0088] The optical measurement device 100 measures the distance from the device, specifically, the sensor head 20, to the measurement object TA at a predetermined measurement cycle. The optical measurement device 100 can also measure a change in distance relative to a certain position, that is, a displacement, at a predetermined measurement cycle.

[0089] The optical measurement device 100 of this embodiment is a confocal measurement device comprising a confocal optical system. In this confocal optical system, for example, the first opening 21a of the first slit member 21, which transmits at least a portion of the light from the light source 10, and the second opening 26a of the second slit member 26, which directs the light to the spectrometer 30, are conjugately arranged. "Conjugately arranged" means that the first opening 21a and the second opening 26a are designed so that, when illumination light from the light source 10 forms a point source at the position of the first opening 21a, is focused (hereinafter referred to as "focused") on the surface of the object to be measured TA, its reflected light is also simultaneously focused at the second opening 26a. For example, as described later, light passing through the linear first opening 21a forms a linear spot and irradiates the object to be measured TA. Light of a focused wavelength reflected from the object to be measured TA passes through the second opening 26a and is directed to the spectrometer 30.

[0090] The light source 10 is configured to emit light containing a plurality of wavelength components. The light source 10 operates based on a control signal input from a control unit (not shown), and for example, changes the light intensity based on the control signal.

[0091] Preferably, the light source 10 emits light having multiple wavelength components. In this case, the light source 10 is configured to include, for example, a white light emitting diode (LED) to generate white light. This facilitates chromatic aberration of the light in the diffraction lens 23 described later.

[0092] However, the light emitted by the light source 10 is not limited to white light as long as it includes a wavelength range covering the distance range required for the optical measurement device 100 .

[0093] The optical fiber 11 for projecting light is an optical fiber that transmits light from the light source 10. The optical fiber may be a single core having a single core or a multi-core having multiple cores. One end of the optical fiber 11 for projecting light ( Figure 1 The right end in the middle) is optically connected to the light source 10, and the other end ( Figure 1 The left end in FIG) is optically connected to the sensor head 20.

[0094] Preferably, the light-emitting optical fiber 11 comprises a plastic optical fiber (POF). Plastic optical fibers, for example, have a larger ratio (proportion) of core diameter to cladding diameter than glass optical fibers. In this embodiment, for example, when the diameter of the light source 10 is 1 mm, a plastic optical fiber with a cladding diameter of 1000 μm and a core diameter of 980 μm is used as the light-emitting optical fiber 11.

[0095] The first slit member 21 is a limiting member having a first opening 21a through which a portion of light passes. The first slit member 21 is configured so that a portion of the light from the light source 10 emitted from the light-emitting optical fiber 11 passes through the first opening 21a. Specifically, the first slit member 21 is arranged so that at the other end ( Figure 1 The optical axis AX passes through the first opening 21a in the optical path of the projected light between the left end in FIG1 and the half mirror 22. Thus, the light from the light source 10 passes through the first opening 21a. With this structure, the first opening 21a serves as a light source, forming a point on the object TA with the same shape as the opening.

[0096] Preferably, the direction in which the linear first opening 21a extends is perpendicular to the direction of light reflected by the later-described half mirror 22, for example, the X-axis direction. For example, the first slit member 21 is arranged so that the direction in which the linear first opening 21a extends is the direction of an axis (Y-axis) perpendicular to the X-axis and the Z-axis.

[0097] The half mirror 22 is configured to transmit a part of the light from the light source 10 toward the diffraction lens 23. Also, the half mirror 22 is configured to reflect a part of the reflected light from the measurement target object TA toward the second slit member 26 in the X-axis direction. The half mirror 22 is configured, for example, so that the reflected light becomes an angle of 90 degrees with respect to the optical axis AX. In addition, the half mirror 22 can also be replaced with a polarization beam splitter, for example.

[0098] In this way, the half mirror 22 separates the optical path of the reflected light from the optical path of the light from the light source 10, and thus, for example, it is not necessary to use an optical coupler to branch the reflected light from the light of the light source (to split the light), and it is possible to prevent the generation of noise light due to the reflected light from the first opening 21a.

[0099] The diffraction lens 23 is configured to cause chromatic aberration in the direction of the optical axis AX of the light from the light source 10. Specifically, the diffraction lens 23 has a diffraction surface DS formed with a diffraction pattern for generating chromatic aberration. The objective lens 24 is configured to concentrate and irradiate the light having generated chromatic aberration to the measurement target object TA. In addition, in the lens group including the diffraction lens 23 and the objective lens 24, a conversion lens that converts light into parallel light can also be included.

[0100] The light extinction member 25 is, for example, a member for reducing crosstalk. In general, the so-called crosstalk is a phenomenon in which light of a wavelength that has not been focused, that is, focused to the measurement target object, is incident to the opening of the slit member. When crosstalk occurs and the light of the wavelength that has not been focused is received by the light receiving sensor through the opening, the measurement accuracy of the distance or displacement of the measurement target object deteriorates.

[0101] The light extinction member 25 is configured to suppress the light of the wavelength that has not been focused in the second slit member 26 from being received by the light receiving sensor 35 described later. The light extinction member 25 includes, for example, at least one of a member that absorbs light for reducing crosstalk and a member that can shield light for reducing crosstalk. Also, the light extinction member 25 can include, for example, at least one of (1) a member that absorbs light, (2) a member that deviates light (for example, changes the direction of propagation of light, etc.), (3) a member that reflects light, and (4) a member that scatters light. For example, the light extinction member 25 can include a member containing a material that is not transparent or substantially not transparent to light.

[0102] The light extinction member 25 is disposed on the path of light from the objective lens 24 toward the light splitter 30. Specifically, the light extinction member 25 is disposed on the surface BS on the opposite side of the diffraction surface DS in the diffraction lens 23. In addition, the surface BS on the opposite side of the diffraction surface DS is preferably a flat surface, but is not limited thereto. According to this configuration, since the light extinction member 25 is disposed on the surface BS on the opposite side of the diffraction surface DS in the diffraction lens 23, it is not necessary to greatly change the original configuration of the optical measurement device in order to dispose the light extinction member 25, and thus it is possible to further improve the measurement accuracy of the position of the measurement target object TA at low cost.

[0103] The second slit member 26 is a restriction member that has a second opening 26a through which a portion of light passes. The second slit member 26 is configured so that a portion of light separated from the optical path of reflected light from the measurement target object TA by the half mirror 22 passes through the second opening 26a. Specifically, the second slit member 26 is disposed so that light reflected by the surface of the measurement target object TA converges toward the objective lens 24, the diffraction lens 23, the half mirror 22, and the second slit member 26, and passes through the second opening 26a.

[0104] The second opening 26a has a linear shape, like the first opening 21a described above. The direction in which the linear second opening 26a extends is, for example, configured to be the direction of an axis (Y axis) perpendicular to the X axis and the Z axis.

[0105] The light-receiving optical fiber 27 is an optical fiber that propagates light that has passed through the second opening 26a. The optical fiber can be a single-core having a single core, or a multi-core having a plurality of cores. The light-receiving optical fiber 27 is disposed so that one end (left end in the drawing) thereof is optically connected to the sensor head 20, and light that has passed through the second opening 26a is incident to the end surface of the one end. Furthermore, the other end (right end in the drawing) of the light-receiving optical fiber 27 is optically connected to the light splitter 30. Figure 1 Figure 1

[0106] The light-receiving optical fiber 27, like the light-projecting optical fiber 11, preferably includes a plastic optical fiber. In the present embodiment, for example, in the case where the diameter of the light source 10 is 1 [mm], a plastic optical fiber having a clad diameter of 1000 [μm] and a core diameter of 980 [μm] is used as the light-receiving optical fiber 27.

[0107] The light splitter 30 is configured to acquire light propagated by the light-receiving optical fiber 27, and measure the spectrum of the light. The light splitter 30 includes, for example, a third slit member 31, a first lens 32, a diffraction grating 33, a second lens 34, a light-receiving sensor 35, and a processing circuit 36.

[0108] ​​The third slit member 31 is a limiting member having a third opening 31a formed therein, through which a portion of light passes. The third slit member 31 is configured so that a portion of the reflected light propagated by the light-receiving optical fiber 27 passes through the third opening 31a. Specifically, the third slit member 31 is arranged so that light emitted from the other end face of the light-receiving optical fiber 27 enters the third opening 31a and passes therethrough.

[0109] The third opening 31a has a linear shape similar to the first opening 21a and the second opening 26a described above. The linear third opening 31a extends in, for example, an axis (Y axis) perpendicular to the X axis and the Z axis.

[0110] The first lens 32 is configured to convert the reflected light that has passed through the third opening 31a into substantially parallel light. The diffraction grating 33 disperses (also referred to as "spectroscopy") the converted reflected light into wavelength components. The second lens 34 focuses the dispersed reflected light. The diffraction grating 33 may also be another component for dispersing light, such as a prism.

[0111] The light receiving sensor 35 is configured to receive the dispersed reflected light and measure the spectrum of the light, and the processing circuit 36 ​​is configured to read out a light reception signal of the light receiving sensor 35 .

[0112] More specifically, the light receiving sensor 35 is configured to detect the amount of light received for each wavelength component of the dispersed reflected light. The light receiving sensor 35 comprises a plurality of light receiving elements. Each light receiving element is arranged one-dimensionally, corresponding to the dispersion direction of the diffraction grating 33, i.e., the wavelength direction. Thus, each light receiving element is positioned corresponding to each wavelength component of the dispersed reflected light, enabling the light receiving sensor 35 to detect the amount of light received for each wavelength component.

[0113] Each light-receiving element of the light-receiving sensor 35 corresponds to one pixel. Therefore, it can be said that the light-receiving sensor 35 is configured so that each of the multiple pixels can detect the amount of received light. Furthermore, the light-receiving elements are not limited to being arranged one-dimensionally; a two-dimensional arrangement is also possible. In this case, the light-receiving elements are preferably arranged two-dimensionally on the detection surface of the diffraction grating 33, for example, including the dispersion direction.

[0114] Each light-receiving element accumulates charge based on the amount of light received during a predetermined exposure time, based on a control signal input from the processing circuit 36. Furthermore, each light-receiving element outputs an electrical signal corresponding to the stored charge during periods outside the exposure time, i.e., during the non-exposure time, based on the control signal input from the processing circuit 36. Thus, the amount of light received during the exposure time is converted into an electrical signal, and the light-receiving signal of the light-receiving sensor 35 is read.

[0115] Thus, the light spectrum of the light that has passed through the third opening 31a of the third slit member 31 is measured by the light receiving sensor 35, whereby the light of a desired shape can be formed through the third opening 31a, and therefore, for example, by making the direction (longitudinal direction) in which the third opening 31a extends correspond to the longitudinal direction of each light receiving element of the light receiving sensor 35, it is possible to increase the amount of light received in the light receiving element.

[0116] The processing circuit 36 interprets the wavelength and the amount of light of the received light as the distance up to the measurement target TA on the basis of the light receiving signal of the light receiving sensor 35. The processing circuit 36 can obtain a distribution signal of the amount of light received by each light receiving element of the light receiving sensor 35, i.e., each wavelength (hereinafter referred to simply as "light amount distribution signal"), from the light receiving signal of the light receiving sensor 35. The processing circuit 36 outputs the light amount distribution signal to a control unit not shown.

[0117] In the present embodiment, as the third slit member 31, a linear slit is employed, and as the light receiving sensor 35, a one-dimensional complementary metal oxide semiconductor (CMOS) image sensor in which a plurality of light receiving elements are arranged in one dimension is employed. That is, the optical measurement device 100 is premised on one-dimensional measurement. Thus, the light receiving sensor 35 includes a plurality of light receiving elements arranged in one dimension, whereby it is possible to measure the measurement target TA at a low cost compared to the case where a plurality of light receiving elements are arranged in two dimensions.

[0118] In addition, the optical measurement device 100 can employ, for example, a two-dimensional CMOS image sensor as the light receiving sensor 35.

[0119] Next, the measurement error of the optical measurement device of an embodiment will be described with reference to Figure 2 Figure 2 is a schematic diagram illustrating the measurement of the measurement target TA by the optical measurement device 100 in an embodiment.

[0120] In the case of measuring the displacement of the measurement target TA, as shown in Figure 2 , the light is irradiated from the sensor head 20 to the measurement target TA while moving at least one of the sensor head 20 and the measurement target TA in a direction (X-axis direction in Figure 2 ). Thus, the surface of the measurement target TA is scanned, and the distance change, i.e., the displacement, from the sensor head 20 up to the surface of the measurement target TA is measured. At this time, the optical measurement device 100 is a displacement measurement device.

[0121] ​Generally, it is considered that the precision in such measurement, i.e., the measurement error, is approximately equal to the total of errors caused by three main reasons. That is, a linearity error, a resolution error, and a movement resolution error. The linearity error is an error (deviation) with respect to the linearity (linearity) of the measurement output with respect to the displacement amount, and with respect to an ideal straight line (deviation). The resolution error is an error (deviation) of the measured value when the sensor head 20 and the measurement target object TA are set to a stationary state. The movement resolution error is an error (deviation) of the measured value when at least one of the sensor head 20 and the measurement target object TA is moved.

[0122] As shown in Figure 2 , in a case where the measurement target object TA is, for example, a metal subjected to cutting processing or hairline processing, the surface thereof becomes a rough surface having fine irregularities. In the measurement error when the rough surface of the measurement target object TA is scanned, the movement resolution error is known to be relatively large. Therefore, in a case where the measurement target object TA having a rough surface is measured, it is important to improve the movement resolution in order to reduce the measurement error.

[0123] On the other hand, for example, in a case where a surface subjected to mirror processing or the like is scanned, the movement resolution error in the measurement error is very small. Thus, unlike the example shown in Figure 2 , in a case where the measurement target object having a mirror surface is measured, it is important to improve the linearity error and the resolution error in order to reduce the measurement error.

[0124] Further, if the diameter of light (hereinafter referred to as "spot diameter") irradiated to the measurement target object TA is increased, the measurement value based on the wavelength focused within the spot diameter is averaged. That is, it is known that, in measurement of a rough surface, by increasing the spot diameter, the irregularities of the rough surface can be averaged, and thus the measurement error of the rough surface can be effectively reduced.

[0125] Next, the relationship between the spot diameter and the depth of field of the optical measurement device of an embodiment will be described with reference to Figure 3 . Figure 3 is a conceptual diagram for explaining the performance of the optical measurement device of the confocal system.

[0126] Figure 3 In the sensor head SH of the optical measurement device of the confocal system shown in , if the core diameter of the optical fiber OF that propagates light from a light source not shown is φp, the focal length of the diffractive lens group L1 is fl, and the focal length of the objective lens group L2 is f2, the depth of field is represented as the following formula (1).

[0127] Depth of field ∝ 2 * (f2) 2 * φp / [fl * {1 / 2fl 2 + 1} 1 / 2 ]... (1)

[0128] As is clear from equation (1), the depth of field is in a positive correlation with the square of the core diameter φp of the optical fiber F and the focal length f2 of the objective lens group L2, and is in an inverse correlation with the focal length f1 of the diffraction lens group L1. Also, it is known that the smaller the depth of field, the higher the performance of linearity and resolution, and the like, in inverse correlation with the depth of field.

[0129] Further, it is known that the depth of field is approximately equal to the half-peak width of the light-receiving amount distribution signal. The half-peak width is known as an index indicating the degree of spread of a Gaussian distribution. In the case of the light-receiving amount distribution signal, the half-peak width is, for example, the length (width) of the line of the light-receiving amount of 50% of the peak (maximum value) of the light-receiving amount and the two intersection points of the light-receiving amount distribution signal. In the following description, the half-peak width refers to the half-peak full width, except in the case where it is specifically indicated.

[0130] On the other hand, Figure 3 In the confocal type optical measurement apparatus shown, the point diameter is represented as equation (2) below.

[0131] Point diameter ∝ φp * f2 * f1 -1 (2)

[0132] As is clear from equation (2), the point diameter is in a positive correlation with the core diameter φp of the optical fiber F and the focal length f2 of the objective lens group L2, and is in an inverse correlation with the focal length f1 of the diffraction lens group L1. That is, if the point diameter is increased, the depth of field also becomes large (deep), and thus the performance of linearity and resolution, and the like, will decrease.

[0133] Here, the light-receiving amount distribution signal in the optical measurement apparatus of the prior art will be described with reference to Figure 4 Figure 4 is a graph illustrating the light-receiving amount distribution signal of the confocal type optical measurement apparatus using a pinhole. Figure 4 In the graph, the horizontal axis is the wavelength, and the vertical axis is the light-receiving amount. The measurement sites 1, 2, and 3 are the measurement sites on the surface of the measurement target object TA when the sensor head 20 is moved in the X-axis direction to perform measurement, and respectively indicate different sites in the X-axis direction. Also, in the graphs of the measurement sites 2 and 3, the light-receiving amount distribution signal measured at the measurement site 1 is indicated by a broken line. Figure 2

[0134] Figure 4 The light-receiving amount distribution signal shown in is a waveform indicating the light-receiving amount distribution of each wavelength. In the confocal type optical measurement apparatus using a pinhole, point measurement of light is performed in the light-receiving sensor. At this time, by setting the point diameter to be small, as shown in Figure 4

[0135] ​​​On the other hand, it is clear from the graphs of the measurement site 2 and the measurement site 3 that the wavelength that becomes the peak (maximum value) of the light receiving amount greatly varies depending on the measurement site. Therefore, the error due to the movement resolution becomes large.

[0136] Next, the light receiving amount distribution signal in the optical measurement apparatus according to an embodiment will be described with reference to Figure 5 Figure 5 is a graph that illustrates the light receiving amount distribution signal of the optical measurement apparatus 100 in the embodiment. Figure 5 In the graph, the horizontal axis is the wavelength, and the vertical axis is the light receiving amount. The measurement site 1, the measurement site 2, and the measurement site 3 are measurement sites on the surface of the measurement target object TA when the sensor head 20 is moved in the X-axis direction to perform measurement, and respectively indicate different sites in the X-axis direction. Also, in the graphs of the measurement site 2 and the measurement site 3, the light receiving amount distribution signal measured at the measurement site 1 is indicated by a broken line. Figure 2

[0137] Figure 5 The light receiving amount distribution signal illustrated in Figure 4 is also a waveform that indicates the light receiving amount distribution of each wavelength. In the optical measurement apparatus 100 of the embodiment, the light from the light source 10 is irradiated to the measurement target object TA using the first slit member 21, and thus a linear light source that is the same shape as the first opening 21a is generated by the light passing through the linear first opening 21a, and a linear line point is formed on the surface of the measurement target object TA.

[0138] Therefore, as illustrated in Figure 5 , the light receiving amount distribution signal of the optical measurement apparatus 100 can also narrow the half-value width as in the related art illustrated in Figure 4 , and thus it is possible to maintain the performance such as linearity and resolution at a high level.

[0139] Also, a part of the reflected light from the measurement target object TA passes through the second opening 26a of the second slit member 26, and the light that has passed through the second opening 26a has distance information (height information) at a plurality of points that are linearly continuous on the surface of the measurement target object TA. Since the light that has passed through the second opening 26a is propagated using the light receiving optical fiber 27, the light that has passed through the second opening 26a is mixed. As a result, it becomes a state in which the position information in one direction in which the line point of the surface of the measurement target object TA extends is lost, and on the other hand, the distance information (height information) at the plurality of points that are focused in the one direction in which the line point extends is integrated.

[0140] ​​In the present embodiment, an example in which the first opening 21a and the second opening 26a each have a linear shape is described, but the present application is not limited thereto. For example, the first opening 21a and the second opening 26a can each have a shape including a plurality of pinholes. In this case, the first opening 21a and the second opening 26a can achieve both the confocal effect and the effect of averaging the unevenness of the rough surface. In addition, the linear shape of the first opening 21a and the second opening 26a can be considered to be a shape in which a plurality of pinholes are continuously arranged.

[0141] In this way, the first opening 21a of the first slit member 21 has a shape including a plurality of pinholes, whereby a line dot extending in one direction can be formed on the surface of the measurement target TA without increasing the point diameter in the short diameter direction of the opening, and thus the depth of field can be maintained without changing. Thus, it is possible to suppress the degradation of performance such as linearity and resolution. Furthermore, the reflected light that has passed through the second opening 26a of the second slit member 26 is propagated by the light-receiving optical fiber 27, whereby the light that has passed through the second opening 26a is mixed and the distance information (height information) at the plurality of points where the light is focused in the one direction in which the line dot extends is integrated, and thus the unevenness of the rough surface in the line dot is averaged, and it is possible to suppress the variation caused by the measurement site of the wavelength of the focused light. Thus, it is possible to reduce the measurement error of the rough surface of the measurement target TA.

[0142] Furthermore, the optical measurement device 100 is a displacement measurement device that measures the displacement of the measurement target, and thus it is possible to easily realize a displacement measurement device that reduces the displacement measurement error of the rough surface of the measurement target TA.

[0143] Next, the first slit member to the third slit member of the optical measurement device of one embodiment will be described with reference to Figure 6 and Figure 7 . Figure 6 is a plan view illustrating the second slit member 26 of the optical measurement device 100 in one embodiment. Figure 7 is a plan view illustrating the third slit member 31 of the optical measurement device 100 in one embodiment. Note that, in order to simplify the description, the second slit member 26 is described in Figure 6 , and thus the first slit member 21 is the same as or substantially the same as the second slit member 26, and the illustration and description thereof are omitted.

[0144] As illustrated in Figure 6 , the second slit member 26 has a shape that is rectangular when viewed in the Y-axis and Z-axis directions, and the second opening 26a has a linear shape extending in one direction (the Y-axis direction) in the second slit member 26. Figure 6The second opening 26a has a linear shape extending in the Y-axis direction (in the Y-axis direction). More specifically, the second opening 26a has a rectangular shape that is long in the Y-axis direction and short in the Z-axis direction. For example, the length of the second opening 26a in the Y-axis direction is 1000 μm and the length in the Z-axis direction is 50 μm. The shape of the second opening 26a corresponds to the shape of the first opening 21a. Therefore, the first opening 21a (not shown) has a linear shape extending in one direction and a rectangular shape, similar to the second opening 26a.

[0145] In addition, if Figure 6 As shown, the second opening 26a may have multiple linear shapes. The first opening 21a (not shown) may also have multiple linear shapes, similar to the second opening 26a. Furthermore, the second opening 26a may be roughly rectangular with at least one corner having a radius (R) or chamfered corners. Furthermore, the second opening 26a may have other shapes, such as a polygon (other than a square) or an ellipse, as long as it is linear and corresponds to the shape of the first opening 21a.

[0146] In this way, the first opening 21 a has a linear shape, and the shape of the second opening 26 a corresponds to the shape of the first opening 21 a , thereby making it possible to easily form a line point extending in one direction on the surface of the measurement object TA.

[0147] Furthermore, it is preferred that Figure 6 As shown, the second slit member 26 is formed with a plurality of second openings 26a, and the first slit member 21 (not shown) is also formed with a plurality of first openings 21a. This further averages the unevenness of the rough surface within the line point, and by increasing the amount of light passing through the second openings 26a, it is possible to perform high-speed measurement of the measurement object TA.

[0148] like Figure 7 As shown, the third slit member 31 has a rectangular shape when viewed from above along the Y axis and the Z axis, and the third opening 31a has a Figure 7 The third opening 31a has a linear shape extending in the Y-axis direction (in the Y-axis direction). More specifically, the third opening 31a has a rectangular shape that is long in the Y-axis direction and short in the Z-axis direction. Similarly to the second opening 26a, the shape of the third opening 31a may be a substantially rectangular shape, a polygonal shape (other than a square), an elliptical shape, or the like.

[0149] Next, refer to Figure 8 A light-emitting optical fiber and a light-receiving optical fiber of an optical measurement device according to one embodiment will be described. Figure 8 : is a plan view illustrating the end face of the light-receiving optical fiber 27 of the optical measurement device 100 in one embodiment. Figure 8The end face of the light-receiving optical fiber 27 shown is the end face on the second slit member 26 side. The second opening 26a of the second slit member 26 is indicated by a broken line. Also, for simplicity of explanation, the light-receiving optical fiber 27 is described in Figure 8 the first embodiment, the light-irradiating optical fiber 11 is the same as or substantially the same as the light-receiving optical fiber 27, and thus the illustration and description thereof are omitted.

[0150] As shown in Figure 8 , the light-receiving optical fiber 27 is the aforementioned plastic optical fiber. In the light-receiving optical fiber 27, the ratio (proportion) of the core diameter 27b to the clad diameter 27a is large. Thus, compared to other types of optical fibers, the ratio (proportion) of the core diameter 27b to the optical fiber diameter 27a can be increased, and thus light from the second opening 26a of the second slit member 26 can be introduced more, and thus the unevenness of the rough surface within the line dot can be further averaged.

[0151] As described above, in a case where a slit member is used to irradiate a line dot to a surface of a measurement target object as in the optical measurement device 100 of the first embodiment, unfocused noise light from an adjacent measurement point can be received by the light-receiving sensor through the opening. Thus, crosstalk caused by the noise light can occur.

[0152] Next, the light-blocking member of the optical measurement device of an embodiment will be described with reference to Figure 9 . Figure 9 is a plan view illustrating the light-blocking member 25 of the optical measurement device 100 in an embodiment.

[0153] As shown in Figure 9 , the light-blocking member 25 is disposed, for example, on a surface BS on the opposite side of the diffraction surface DS in the diffraction lens 23. In addition, it is preferable that the surface BS on the opposite side of the diffraction surface DS be a flat surface, but it is not limited thereto. According to this structure, since the light-blocking member 25 is disposed on the surface BS on the opposite side of the diffraction surface DS in the diffraction lens 23, the original structure of the optical measurement device does not need to be greatly changed in order to dispose the light-blocking member 25, and thus the measurement accuracy of the measurement target object TA can be further improved at low cost.

[0154] The light-blocking member 25 only needs to be configured to suppress light of a wavelength that is not focused in the second slit member 26 from being received in the light-receiving sensor 35. Thus, the light-blocking member 25 is not limited to the case where it is disposed in the diffraction lens 23. For example, the light-blocking member 25 is disposed in the light-irradiating optical fiber 11. Figure 1The light path of the reflected light from the measurement target object TA is configured between the objective lens 24 and the diffraction grating 33 included in the light splitter 30, as shown. Specifically, the light extinction member 25 can also be configured on the objective lens 24, the first lens 32, or the diffraction grating 33. In addition, the light extinction member 25 is not limited to the case of being configured on a lens or a member, but can also be configured as a separate member between the objective lens 24 and the diffraction grating 33. According to this configuration, the light extinction member 25 can be configured on the light path of the reflected light between the objective lens 24 and the diffraction grating 33, and thus the degree of freedom with respect to the configuration position of the light extinction member 25 is increased.

[0155] Further, the light extinction member 25 has a shape corresponding to the shape of the second opening 26a in the second slit member 26. Specifically, as shown in Figure 9 The light extinction member 25 has a linear shape, as shown. According to this configuration, by configuring the light extinction member 25 having a shape corresponding to the shape of the second opening 26a in the second slit member 26, it is possible to effectively reduce crosstalk. Further, the light extinction member 25 is configured to correspond to the configuration position of the second opening 26a in the second slit member 26. According to this configuration, by configuring the light extinction member 25 at a position corresponding to the configuration position of the second opening 26a in the second slit member 26, it is possible to appropriately configure and effectively reduce crosstalk.

[0156] In addition, the range in which the light extinction member 25 is configured can also be appropriately set according to the intensity or spread of light, and the like. Further, the thickness of the light extinction member 25 can also be appropriately set according to the material included in the light extinction member 25, the content of the member, or the configuration state of each lens.

[0157] In this way, by configuring the light extinction member 25 on the light path of the reflected light to suppress light of a wavelength that is not focused in the second slit member 26 from being received by the light receiving sensor 35, it is possible to reduce crosstalk, and thus it is possible to improve the measurement accuracy of the measurement target object TA.

[0158] (First Modified Example)

[0159] Next, a first modified example of the optical measurement device of an embodiment will be described with reference to Figure 10 In addition, the same or similar symbols are attached to the same or similar structures as those of the optical measurement device shown in Figure 1 to Figure 9 and appropriate description thereof is omitted. Further, the same effects as those of the same structures will not be mentioned one by one.

[0160] Figure 10 is a configuration diagram illustrating the outline configuration of the optical measurement device 100A in the first modified example of the embodiment.

[0161] Figure 10 The optical measurement device 100A shown in Figure 1The optical measurement device 100 shown is different in that it includes an optical coupler 40 and a light-emitting / light-receiving optical fiber 41 instead of the half mirror 22 and the second slit member 26 .

[0162] like Figure 10 As shown, the optical path of the reflected light is not separated from the optical path of the light from the light source 10, and the light reflected from the surface of the measured object TA is focused toward the objective lens 24, the diffraction lens 23 and the first slit member 21 and passes through the first opening 21a. Figure 10 In the illustrated optical measurement device 100A, a first limiting member having a first opening through which a portion of light from the light source 10 passes, and a second limiting member having a second opening through which a portion of light reflected from the object to be measured TA passes are identical first slit members 21. This single limiting member improves the measurement accuracy of the object to be measured TA at a lower cost than when multiple limiting members are used.

[0163] One end of the light-emitting optical fiber 11 ( Figure 10 The right end in FIG) is optically connected to the light source 10, and the light receiving optical fiber 27 is configured so that one end ( Figure 10 The right end of the optical fiber 11 is optically connected to the third slit member 31, and the light emitted from the end face of the one end passes through the third opening 31a. Figure 10 The left end of the light receiving optical fiber 27 and the other end of the light receiving optical fiber 27 ( Figure 10 The left end of the projection / reception optical fiber 41 and the other end of the projection / reception optical fiber 41 ( Figure 10 The right end in FIG) is optically coupled via an optical coupler 40.

[0164] The light-emitting / light-receiving optical fiber 41 is an optical fiber that propagates light. The optical fiber may be a single-core optical fiber having a single core or a multi-core optical fiber having a plurality of cores.

[0165] The optical coupler 40 is configured to branch the reflected light of the measurement target object TA from the light from the light source 10. The optical coupler 40 is configured to include, for example, a fusion-stretching type (also referred to as a fused-stretching type) optical coupler.

[0166] Specifically, the optical coupler 40 transmits light incident from the light-emitting optical fiber 11 to the light-emitting / receiving optical fiber 41, and splits the light incident from the light-emitting / receiving optical fiber 41 and transmits the split light to the light-emitting optical fiber 11 and the light-receiving optical fiber 27, respectively. Furthermore, the light transmitted from the light-emitting / receiving optical fiber 41 to the light-emitting optical fiber 11 via the optical coupler 40 terminates in the light source 10.

[0167] Thus, the optical coupler 40 branches the reflected light of the measurement target object TA from the light from the light source 10, and thereby includes a single restriction member, so that the optical measurement device 100A can easily achieve the measurement error reduction of the rough surface.

[0168] (Second Modification)

[0169] Next, a second modification of the optical measurement device of an embodiment will be described with reference to Figure 11 to Figure 14 FIGS. 17A to 17D. In addition, the same or similar signs are attached to the same or similar structures as those of the optical measurement device shown in FIGS. 1A to 1D, and the description thereof is appropriately omitted. Also, the same effects as those of the same structures are not mentioned one by one. Figure 1 to Figure 9

[0170] Figure 11 FIG. 17A is a plan view illustrating a first slit member 21A of a first example of the optical measurement device 100 in the second modification of the embodiment. Figure 12 FIG. 17B is a plan view illustrating a first slit member 21B of a second example of the optical measurement device 100 in the second modification of the embodiment. Figure 13 FIG. 17C is a plan view illustrating a first slit member 21C of a third example of the optical measurement device 100 in the second modification of the embodiment. Figure 14 FIG. 17D is a plan view illustrating a first slit member 21D of a fourth example of the optical measurement device 100 in the second modification of the embodiment. In addition, in order to simplify the description, the first slit member 21A, the first slit member 21B, the first slit member 21C, and the first slit member 21D are described respectively in FIGS. 17A to 17D. The second slit member 26A, the second slit member 26B, the second slit member 26C, and the second slit member 26D are the same as or substantially the same as the corresponding first slit member 21A, the first slit member 21B, the first slit member 21C, and the first slit member 21D. That is, the second openings 26b, 26c, 26d, and 26e of the second slit member 26A, the second slit member 26B, the second slit member 26C, and the second slit member 26D are the same as or substantially the same as the first openings 21b, 21c, 21d, and 21e of the corresponding first slit member 21A, the first slit member 21B, the first slit member 21C, and the first slit member 21D. Therefore, the second slit member 26A, the second slit member 26B, the second slit member 26C, and the second slit member 26D omit the illustration and the description thereof. Figure 11 to Figure 14

[0171] The optical measurement device 100 in the second modification is the same as or substantially the same as the optical measurement device 100 shown in FIGS. 1A to 1D. Figure 1 to Figure 9 ​​The optical measuring device 100 shown is substantially the same, but differs in that it includes a first slit member 21A, a first slit member 21B, a first slit member 21C, and a first slit member 21D having openings different from those of the first slit member 21, and a second slit member 26A, a second slit member 26B, a second slit member 26C, and a second slit member 26D having openings different from those of the second slit member 26.

[0172] like Figure 11 As shown in the first example, a first opening 21b is formed in the first slit member 21A. The first opening 21b has a rectangular shape when viewed from above along the Y axis and the X axis, and has a plurality of openings 21b extending in one direction ( Figure 11 More specifically, the first opening 21b has a rectangular shape that is long in the Y-axis direction and short in the X-axis direction.

[0173] The shape of the first opening 21b is not limited to a straight line extending in one direction. The first opening 21b may also be, for example, a semicircular shape or a curved shape when viewed from above along the Y-axis and the X-axis. Similarly, the second slit member 26A may also be curved.

[0174] like Figure 12 As shown, in the first slit member 21B of the second example, a first opening 21c including a plurality of pinholes arranged in a row is formed. Each pinhole of the first opening 21c has a circular or substantially circular shape when viewed from above along the Y axis and the X axis, and is arranged in a direction ( Figure 12 Y-axis direction) configuration.

[0175] like Figure 13 As shown in FIG. 2 , in the first slit member 21C of the third example, two first openings 21d are formed. Figure 11 The first opening 21b shown in the figure also has a rectangular shape when viewed from above along the Y axis and the X axis, and has a Figure 13 A linear shape extending in the Y-axis direction).

[0176] In addition, it is not limited to the case where two first openings 21d are formed. In the first slit member 21C, more than three first openings may be formed. Moreover, the two first openings 21b are not limited to the case where they are parallel to each other. For example, the two first openings 21b may be configured to form a predetermined angle θ (0°<θ≦90°) when viewed from above on the Y axis and the X axis. In this case, when the predetermined angle θ is 90°, one of the two first openings 21d is along a direction ( Figure 13 The other extends along another orthogonal direction ( Figure 13 The X-axis direction in FIG.

[0177] As Figure 14 shown in FIG. 4, in the first slit member 21D of the fourth example, the first openings 21e including a plurality of pinholes are arranged in two rows. Each pinhole of the first openings 21e is aligned with each pinhole of the first openings 21c shown in FIG. 3 in the Y-axis direction. Figure 12 As with each pinhole of the first openings 21c shown in FIG. 3, each pinhole of the first openings 21e has a circular or substantially circular shape when viewed in the Y-axis and X-axis directions, and is arranged in one direction (the Y-axis direction in FIG. 4). Furthermore, each row including a plurality of pinholes is arranged in parallel to each other. Figure 14

[0178] In addition, the first openings 21e including a plurality of pinholes are not limited to the case where they are arranged in two rows. The first openings 21e can be arranged in three or more rows.

[0179] Thus, even in the structures of the first slit member 21A, the first slit member 21B, the first slit member 21C, and the first slit member 21D, the first openings 21b, the first openings 21c, the first openings 21d, and the first openings 21e become light sources, thereby forming points on the object TA that are the same shape as the openings. Furthermore, the optical measurement apparatus 100 in the second modified example includes the first slit member 21A, the first slit member 21B, the first slit member 21C, and the first slit member 21D and the corresponding second slit member 26A, the second slit member 26B, the second slit member 26C, and the second slit member 26D, whereby both the confocal effect and the effect of averaging the unevenness of the rough surface can be obtained.

[0180] The above describes an illustrative embodiment of the present application. The optical measurement apparatus 100, the optical measurement apparatus 100A, the first slit member 21, the first slit member 21A, the first slit member 21B, the first slit member 21C, the first openings 21a, the first openings 21b, the first openings 21c, the first openings 21d, and the first openings 21e of the first slit member 21D according to an embodiment of the present application have a shape including a plurality of pinholes. Thus, without increasing the point diameter in the short diameter direction of the opening, it is possible to form line points extending in one direction on the surface of the object TA, and therefore it is possible to maintain the depth of field without changing it. Thus, it is possible to suppress a decrease in performance such as linearity and resolution. Furthermore, the reflected light that has passed through the second openings of the second slit member 26, the second slit member 26A, the second slit member 26B, the second slit member 26C, and the second slit member 26D is propagated by the light-receiving optical fiber 27. Thus, the light that has passed through the second openings is mixed, and the distance information (height information) at the plurality of points where the line points focus in the one direction in which the line points extend is integrated, and therefore the unevenness of the rough surface within the line points is averaged, and it is possible to suppress a change in the measurement site of the wavelength that is focused. Thus, it is possible to reduce the measurement error of the rough surface of the object TA.​

[0181] (Note 1)

[0182] An optical measurement device 100, 100A includes:

[0183] A light source 10 outputs light of a plurality of wavelengths;

[0184] A first restriction member 21, 21A, 21B, 21C, 21D is formed with a first opening 21a, 21b, 21c, 21d, 21e through which a portion of light from the light source 10 passes;

[0185] An optical system for causing light that has passed through the first opening 21a, 21b, 21c, 21d, 21e to produce chromatic aberration along an optical axis;

[0186] An objective lens 24 irradiates the light that has produced chromatic aberration to a measurement target object TA;

[0187] A second restriction member 26, 26A, 26B, 26C, 26D is formed with a second opening 26a, 26b, 26c, 26d, 26e through which a portion of reflected light of the light irradiated to the measurement target object TA passes;

[0188] An optical fiber propagates the light that has passed through the second opening; and

[0189] A light-receiving sensor 35 acquires the propagated light and measures a spectrum of the light,

[0190] The first opening 21a, 21b, 21c, 21d, 21e and the second opening 26a, 26b, 26c, 26d, 26e each have a shape including a plurality of pinholes.

Claims

1. An optical measuring device comprising: a light source, outputting light of multiple wavelengths; a first limiting member having a first opening formed therein for allowing a portion of the light from the light source to pass therethrough; an optical system configured to cause chromatic aberration of light passing through the first opening along an optical axis; an objective lens for irradiating the light with chromatic aberration onto a measurement object; a second limiting member having a second opening formed therein for allowing a portion of reflected light of the light irradiated onto the object to be measured to pass therethrough; an optical fiber, transmitting the light passing through the second opening; as well as A light receiving sensor receives the propagated light and measures the spectrum of the light. The first opening and the second opening each have a shape including a plurality of pinholes, and the optical fiber is arranged so that light passing through the second opening is incident on an end face of one end of the optical fiber.

2. The optical measuring device according to claim 1, wherein The light receiving sensor includes a plurality of light receiving elements arranged in one dimension.

3. The optical measuring device according to claim 1 or 2, further comprising: a third limiting member having a third opening formed therein for allowing a portion of the propagating light to pass therethrough; The light receiving sensor measures a spectrum of light that has passed through the third opening.

4. The optical measuring device according to claim 1 or 2, further comprising: The light extinguishing member is arranged on an optical path of the reflected light to suppress light of a wavelength not focused by the second limiting member from being received by the light receiving sensor.

5. The optical measuring device according to claim 1 or 2, wherein The first opening has a linear shape, The shape of the second opening corresponds to the shape of the first opening.

6. The optical measuring device according to claim 1 or 2, further comprising: an optical path separation element for separating the optical path of the reflected light from the optical path of the light from the light source, The second opening is configured to pass a portion of the reflected light separated by the optical path separation element.

7. The optical measuring device according to claim 1 or 2, wherein The first restricting member and the second restricting member are the same member.

8. The optical measuring device according to claim 7, further comprising: The optical coupler branches the reflected light from the light from the light source.

9. The optical measuring device according to claim 1 or 2, wherein The light from the light source is white light.

10. The optical measuring device according to claim 1 or 2, wherein The optical measuring device is a displacement measuring device that measures the displacement of the measurement object.

11. The optical measuring device according to claim 1 or 2, wherein The first limiting member is formed with a plurality of the first openings, The second restricting member is formed with a plurality of the second openings.

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