JP2017116493A - Confocal displacement meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a confocal displacement meter that can reduce measurement errors.SOLUTION: Light having a plurality of wavelengths is ejected by a light projection unit 120. A plurality of parts of a measurement object S is irradiated with the light ejected by the light projection unit 120. In the light with which the measurement object S is irradiated by a light irradiation unit 1, a chromatic aberration occurs along an optical axis direction due to a lens unit 220. Further the light having the chromatic aberration is converged by the lens unit 220. Light of a wavelength reflected at the plurality of parts of a surface of the measurement object S as is focused on the plurality thereof sequentially passes through an optical fiber 314. A displacement of the measurement object S is calculated on the basis of signal intensity for each wavelength of an average signal corresponding to an average of intensity for each wavelength about the plurality of light sequentially passing through the optical fiber 314. Before the displacement of the measurement object S is calculated, out of light to be received by a light reception unit 140, a component of unnecessary light excluding the light reflected at the surface of the measurement object S as is focused on the surface thereof is removed from the average signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a confocal displacement meter using light having a wide wavelength band.

  A confocal displacement meter is known as a device that measures the displacement of the surface of a measurement object by a non-contact method. For example, Patent Document 1 describes a chromatic point sensor (CPS) system that measures a distance from a predetermined reference position to a measurement object as a displacement of the surface of the measurement object. The CPS of Patent Document 1 has two confocal optical paths. Light of a plurality of wavelengths is input to each optical path, and the light that has passed through one of the optical paths is selectively output to the measurement object.

  The first optical path is configured such that light of different wavelengths is focused at different distances near the surface position of the measurement target in the optical axis direction. The light that has passed through the first optical path is reflected by the surface of the measurement object. Of the reflected light, only the light focused at the position of the opening disposed in the first path as a spatial filter passes through the opening and is guided to the wavelength detector. The spectrum profile (first output spectrum profile) of the light detected by the wavelength detector includes a component indicating the measurement distance (distance-dependent profile component) and also includes a distance-independent profile component.

  The second optical path is configured such that light of different wavelengths is focused at substantially the same distance in the vicinity of the surface position of the measurement object. The light that has passed through the second optical path is reflected by the surface of the measurement object. Of the reflected light, only the light focused at the position of the opening disposed in the second path as a spatial filter passes through the opening and is guided to the wavelength detector. The spectral profile (second output spectral profile) of the light detected by the wavelength detector does not include a distance-dependent profile component but includes only a distance-independent profile component. The second output spectral profile is used to correct for potential measurement errors associated with distance-independent profile components for the first output spectral profile.

JP 2013-130581 A

  In the CPS system described in Patent Document 1, reliability is improved by performing the above correction on the first output spectrum profile. Specifically, the measurement error due to the material component of the measurement object, the spectral profile component of the light source associated with the light source, or the component associated with the wavelength detector is reduced as the distance-independent profile component. However, in the confocal displacement meter, a measurement error with a degree larger than the roughness of the surface occurs due to the influence of irregular reflection on the surface of the measurement object. In the CPS system of Patent Document 1, such a measurement error cannot be reduced.

  An object of the present invention is to provide a confocal displacement meter that can reduce measurement errors.

  (1) A confocal displacement meter according to the present invention is a confocal displacement meter that measures a displacement of a measurement object using a confocal optical system, and a light projecting unit that emits light having a plurality of wavelengths. The optical member that generates chromatic aberration along the optical axis direction in the light emitted from the light projecting unit, converges the light having chromatic aberration and irradiates the measurement object, and the measurement object is irradiated by the optical member. Among the light, a pinhole member having one or a plurality of pinholes that allows light of a wavelength reflected while being focused on the surface of the measurement object to be reflected, and one or more reflected from a plurality of portions of the measurement object A displacement measuring unit that calculates the displacement of the measurement object based on the signal intensity for each wavelength of the average signal corresponding to the average of the intensity for each wavelength for the plurality of lights that have passed through the plurality of pinholes, , The displacement of the measurement object Before leaving, performing first correction processing such that at least a portion of the undesired component corresponding to the unnecessary light is removed except for the light reflected while focusing on the surface of the measurement object from the average signal.

  In the confocal displacement meter, light having a plurality of wavelengths is emitted by the light projecting unit. Chromatic aberration along the optical axis direction is generated by the optical member in the light emitted from the light projecting unit. In addition, light having chromatic aberration is converged by the optical member and irradiated onto the measurement object.

  Of the light irradiated to the measurement object by the optical member, the light having the wavelength reflected while being focused on the plurality of portions on the surface of the measurement object passes through one or more pinholes of the pinhole member. The displacement of the measurement object is calculated based on the signal intensity for each wavelength of the average signal corresponding to the average of the intensity for each wavelength for the plurality of lights that have passed through one or more pinholes.

  Due to irregular reflection on the surface of the measurement object, light focused at a position different from the position of the surface of the measurement object may pass through one or more pinholes. Even in such a case, according to said structure, the intensity | strength for every wavelength about the some light which passed the 1 or several pinhole in the average signal is averaged. As a result, a light component that causes a random measurement error due to irregular reflection is canceled out. Furthermore, the first correction process is performed before the displacement of the measurement object is calculated, so that unnecessary light corresponding to unnecessary light is removed from the average signal except for the light reflected while being focused on the surface of the measurement object. At least some of the components are removed. As a result, it is possible to reduce the displacement error of the measurement object measured by the confocal displacement meter.

  (2) The confocal displacement meter further includes a processing device, a head unit, and an optical fiber connecting the processing device and the head unit, and the processing device includes a part of the displacement measuring unit and a light projecting unit and is displaced. The head unit further includes a first housing that houses a part of the measuring unit and the light projecting unit, and the head unit further includes a second housing that houses the optical member and the pinhole member. In addition, the optical fiber may guide the light emitted from the light projecting unit to the optical member, and at least a part of the optical fiber may be a portion that is not accommodated in the first housing of the displacement measuring unit.

  In this case, the processing device including a part of the light projecting unit and the displacement measuring unit and the head unit including the optical member and the pinhole member are separately provided via the optical fiber. Therefore, it becomes easy to use a head unit including an optical member that generates an appropriate chromatic aberration or an optical member having an appropriate focal length according to the shape or arrangement of the measurement object. Thereby, the displacement of a measurement object can be measured more easily.

  (3) One end of the optical fiber is provided in the first housing, the other end of the optical fiber is provided in the second housing, and the light projecting unit is generated by the light source including the laser diode and the light source A light collecting member that collects light, and a fluorescent light that is provided at one end of the optical fiber and absorbs part of the light collected by the light collecting member and emits light having a plurality of wavelengths to the optical member through the optical fiber It may include the body.

  In this case, since the light generated by the light source is condensed on the phosphor by the condensing member, the amount of light incident on the phosphor can be increased. Thereby, the amount of light having a plurality of wavelengths generated from the phosphor is also increased.

  Further, according to the above configuration, since the phosphor is provided at one end of the optical fiber, light having a plurality of wavelengths efficiently enters the one end of the optical fiber from the phosphor, and is optically transmitted from the other end of the optical fiber. The measurement object is irradiated through the member. Therefore, even when the size of the irradiation region formed on the measurement object is reduced, the amount of light passing through one or a plurality of pinholes is prevented from being significantly reduced. As a result, the size of the irradiation area can be reduced.

  (4) The unnecessary component includes an unnecessary peak whose position on the wavelength axis of the average signal does not depend on the displacement of the object to be measured, and the displacement measuring unit is on the wavelength axis of the average signal before the first correction processing. Based on the position of the unnecessary peak at, a second correction process for correcting the shift of the average signal depending on the temperature on the wavelength axis may be performed.

  In this case, the position of the unnecessary peak on the wavelength axis of the average signal does not depend on the displacement of the measurement target but changes depending on the temperature. Therefore, the position of the unnecessary peak on the wavelength axis of the average signal corresponds to a shift on the wavelength axis of the average signal due to a change in temperature. Therefore, by correcting the shift on the wavelength axis of the average signal depending on the temperature based on the position of the unnecessary peak on the wavelength axis of the average signal, it is possible to compensate for the variation in the measurement result due to the temperature change. .

  (5) The unnecessary peak may include a first peak corresponding to the first unnecessary light that is emitted from the light projecting unit and reflected by the optical member and guided to the displacement measuring unit.

  In this case, since the first unnecessary light does not reach the measurement object, the position of the first peak on the wavelength axis of the average signal does not depend on the displacement of the measurement object. Therefore, by correcting the shift on the wavelength axis of the average signal depending on the temperature based on the position of the first peak on the wavelength axis of the average signal, it is possible to compensate for the variation in the measurement result due to the temperature change. it can.

  (6) The light projecting unit includes a light source and a phosphor that absorbs a part of the light generated by the light source and emits light having a plurality of wavelengths to the optical member, and the unnecessary peak is generated by the light source. The second peak corresponding to the second unnecessary light emitted to the optical member while passing through the phosphor may be included.

  In this case, since the second unnecessary light has a specific wavelength, the position of the second peak on the wavelength axis of the average signal does not depend on the displacement of the measurement object. Therefore, by correcting the shift on the wavelength axis of the average signal depending on the temperature based on the position of the second peak on the wavelength axis of the average signal, it is possible to compensate for the variation in the measurement result due to the temperature change. it can.

  (7) The displacement measuring unit includes a spectroscopic unit that diffracts light by diffracting light that has passed through one or a plurality of pinholes, and the unnecessary peak corresponds to third unnecessary light that is zero-order diffracted by the spectroscopic unit. A third peak may be included.

  In this case, the third unnecessary light, which is the 0th-order diffracted light, is guided in a certain direction by the spectroscopic unit regardless of the wavelength. Therefore, the position of the third peak on the wavelength axis of the average signal is the position of the third unnecessary light. Independent of wavelength. Therefore, the position of the third peak on the wavelength axis of the average signal does not depend on the displacement of the measurement object. Therefore, by correcting the shift on the wavelength axis of the average signal depending on the temperature based on the position of the third peak on the wavelength axis of the average signal, it is possible to compensate for the variation in the measurement result due to the temperature change. it can.

  (8) The unnecessary component includes at least two unnecessary peaks whose positions on the wavelength axis of the average signal do not depend on the displacement of the measurement object, and the displacement measurement unit performs the calculation of the average signal before the first correction process. Based on the positions of at least two unnecessary peaks on the wavelength axis, a third correction process for correcting the scale on the wavelength axis of the average signal depending on the temperature may be performed.

  In this case, the position of the unnecessary peak on the wavelength axis of the average signal does not depend on the displacement of the measurement target but changes depending on the temperature. Therefore, the interval between two unnecessary peaks on the wavelength axis of the average signal corresponds to a deviation of the scale on the wavelength axis of the average signal due to a change in temperature. Therefore, based on the positions of the two unnecessary peaks on the wavelength axis of the average signal, the variation of the measurement result due to the temperature change is compensated by correcting the scale on the wavelength axis of the average signal depending on the temperature. Can do.

  (9) The light projecting unit includes a light source and a phosphor that absorbs part of the light generated by the light source and emits light having a plurality of wavelengths to the optical member, and the displacement measuring unit includes one or more displacement measuring units. The first unnecessary light that includes a spectroscopic unit that reflects and splits the light that has passed through the pinhole, is emitted from the light projecting unit, reflected by the optical member, and guided to the displacement measuring unit. The second peak corresponding to the second unnecessary light generated by the light source and emitted to the optical member while passing through the phosphor, and the third peak diffracted by the zero order in the spectroscopic unit You may include at least 2 peaks among the 3rd peaks corresponding to unnecessary light.

  In this case, since the first unnecessary light does not reach the measurement object, the position of the first peak on the wavelength axis of the average signal does not depend on the displacement of the measurement object. Since the second unnecessary light has a specific wavelength, the position of the second peak on the wavelength axis of the average signal does not depend on the displacement of the measurement object. Since the third unnecessary light that is the 0th-order diffracted light is guided in a certain direction by the spectroscopic unit regardless of the wavelength, the position of the third peak on the wavelength axis of the average signal depends on the wavelength of the third unnecessary light. do not do. Accordingly, by correcting the scale on the wavelength axis of the average signal depending on the temperature based on the positions of at least two of the first to third peaks on the wavelength axis of the average signal, Variations in measurement results can be compensated.

  (10) The pinhole member includes a plurality of pinholes, and the displacement measurement unit reflects the average of the intensities for each wavelength of the plurality of lights reflected by the plurality of portions of the measurement object and passed through the plurality of pinholes. The displacement of the measurement object may be calculated based on the signal intensity for each wavelength of the corresponding average signal.

  In this case, it is possible to acquire a plurality of lights reflected while focusing on a plurality of portions of the measurement object with a simple configuration.

  (11) The displacement measurement unit includes a combining unit that generates a single combined light by combining a plurality of lights acquired by the plurality of light acquiring units, and a spectroscopic unit that splits the combined light generated by the combining unit. A light receiving unit that receives the light split by the spectroscopic unit and outputs an electric light receiving signal indicating the intensity for each wavelength of the combined light generated by the combining unit as an average signal; and an average signal output from the light receiving unit And a calculation unit that performs the first correction process and calculates the displacement of the measurement object based on the corrected average signal.

  In this case, a plurality of light beams respectively passing through the plurality of pinholes are combined by the combining unit before being received by the light receiving unit, thereby generating one combined light. Therefore, the electrical light reception signal indicating the intensity for each wavelength output from the light receiving unit is an average signal obtained by integrating the intensity for each wavelength for a plurality of lights. According to this configuration, there is no need to perform an operation for generating an average signal. Thereby, the displacement of the measurement object can be calculated efficiently at high speed.

  (12) The confocal displacement meter further includes a light irradiation unit that sequentially irradiates the light emitted from the light projecting unit to a plurality of portions of the measurement target, and the optical member is irradiated to the measurement target by the light irradiation unit. The chromatic aberration is caused to converge and the light having the chromatic aberration is converged. The pinhole member includes one pinhole, and the one pinhole is reflected while being focused on a plurality of portions of the measurement object. The light of the wavelength is sequentially passed, and the displacement measuring unit is configured to detect the measurement object based on the signal intensity for each wavelength of the average signal corresponding to the average of the intensity for each wavelength for the plurality of lights sequentially passing through one pinhole. The displacement may be calculated.

  In this case, it is possible to acquire a plurality of lights reflected while focusing on a plurality of portions of the measurement object with a simple configuration.

  (13) The displacement measuring unit receives a plurality of light beams that are sequentially split through a single pinhole, and a plurality of light beams that are sequentially split by the beam splitting unit within a single exposure period. A light receiving unit that outputs an electrical light reception signal indicating the intensity for each wavelength of light as an average signal, and a measurement target based on the corrected average signal while performing a first correction process on the average signal output from the light reception unit And a calculation unit that calculates the displacement of the object.

  In this case, a plurality of lights sequentially passing through one pinhole are received by the light receiving unit within a single exposure period. Therefore, the electrical light reception signal indicating the intensity for each wavelength output from the light receiving unit is an average signal obtained by integrating the intensity for each wavelength for a plurality of lights. According to this configuration, there is no need to perform an operation for generating an average signal. Thereby, the displacement of the measurement object can be calculated efficiently.

  (14) The displacement measuring unit sequentially receives a plurality of light beams sequentially separated by the spectroscopic unit, and sequentially receives a plurality of light beams sequentially passed through one pinhole. An average signal is calculated as the signal intensity for each wavelength by averaging or integrating the light receiving unit that outputs an electrical light receiving signal indicating the intensity for each wavelength and the plurality of light receiving signals output from the light receiving unit for each wavelength. And a calculation unit that performs a first correction process on the plurality of light reception signals output from the light reception unit or the calculated average signal, and calculates a displacement of the measurement object based on the corrected average signal. .

  In this case, a plurality of light receiving signals respectively corresponding to a plurality of lights sequentially passing through one pinhole are output by the light receiving unit. An average signal is calculated by averaging or integrating a plurality of received light signals output from the light receiving unit for each wavelength by the calculating unit. According to this configuration, in calculating the average signal, it is possible to perform a desired average or integration considering a plurality of light intensities. Thereby, the displacement of the measurement object can be calculated more accurately.

  (15) The plurality of portions are located on an annular region on the surface of the measurement object, and the light irradiation unit is configured to irradiate the plurality of portions on the annular region on the surface of the measurement object. In addition, the optical axis of the light emitted by the light projecting unit may be shifted along the surface of the measurement object.

  According to this structure, the burden of the physical operation | movement part of a light irradiation part is small compared with the case where several parts on the linear area | region of the surface of a measurement object are irradiated. Thereby, the lifetime of a light irradiation part can be lengthened.

  (16) The optical member may include a refractive lens having a convex shape and a diffractive lens having a concave shape, and the refractive lens and the diffractive lens may be arranged so that light emitted from the light projecting unit passes therethrough.

  In this case, the direction of chromatic aberration generated by each lens is the same in each lens, and as a result, chromatic aberration on the optical axis of the optical member increases. Thereby, the range which can be measured with a confocal displacement meter can be enlarged.

  According to the present invention, it is possible to reduce measurement errors of a measurement object.

It is a schematic diagram which shows the structure of the confocal displacement meter which concerns on 1st Embodiment. It is an example of a display of the value of the measurement result in a main display part. It is an example of a display of the waveform of the received light signal in the main display part. It is a figure for demonstrating the principle of operation of the confocal displacement meter using a measurement head. It is a figure which shows the relationship between the wavelength of the light received by the light-receiving part, and the intensity | strength of a received light signal. It is the top view and sectional drawing which show the structure of a light projection part. It is a schematic diagram which shows an example of the unnecessary light reflected in a different part from a measurement target object. It is a figure which shows the light-receiving waveform containing an unnecessary component. It is a figure which shows the base waveform of a received light waveform. It is a figure which shows the light reception waveform from which the base waveform was removed. It is a figure which shows the path | route of the light guide | induced to a light-receiving part. It is a figure which shows the light reception waveform of the light guide | induced to the light-receiving part of FIG. It is a schematic diagram which shows the more concrete structure of the confocal displacement meter of FIG. It is a figure for demonstrating the principle of operation of the confocal displacement meter using the measuring head of FIG. It is a figure which shows the optical path of the light at the time of rotation of the drive part of FIG. It is a figure which shows the area | region of the measurement target object irradiated with light by the measurement head of FIG. It is a figure which shows the 1st-4th modification of a lens unit. It is a figure which shows the modification of a light projection part. It is a figure which shows the modification of a spectroscopy part. It is a schematic diagram which shows the structure of the confocal displacement meter which concerns on 2nd Embodiment. It is a figure for demonstrating the principle of operation of the confocal displacement meter using the measuring head of FIG. It is sectional drawing which shows arrangement | positioning of the four optical fibers of FIG. It is a schematic diagram which shows the structure of the confocal displacement meter which concerns on other embodiment.

  Hereinafter, a confocal displacement meter according to an embodiment of the present invention will be described with reference to the drawings.

[1] First Embodiment (1) Basic Configuration of Confocal Displacement Meter FIG. 1 is a schematic diagram showing a configuration of a confocal displacement meter according to the first embodiment. As shown in FIG. 1, the confocal displacement meter 500 includes a processing device 100, a measurement head 200, a light guide unit 300, a PC (personal computer) 600, a main display unit 700, and an operation unit 800. The light guide unit 300 includes a plurality of optical fibers, and optically connects the processing apparatus 100 and the measurement head 200.

  The processing apparatus 100 includes a housing 110, a light projecting unit 120, a spectroscopic unit 130, a light receiving unit 140, an arithmetic processing unit 150, a power supply unit 160, and a sub display unit 400. The housing 110 houses the light projecting unit 120, the spectroscopic unit 130, the light receiving unit 140, the arithmetic processing unit 150, and the power supply unit 160. The sub display unit 400 includes a display such as a 7-segment display or a dot matrix display, and is attached to the housing 110. The light projecting unit 120 is configured to emit light having a wide wavelength band (for example, 500 nm to 700 nm), that is, light having a plurality of wavelengths. A detailed configuration of the light projecting unit 120 will be described later. The light emitted from the light projecting unit 120 is input to an optical fiber 311 of the light guide unit 300 described later.

  The spectroscopic unit 130 includes a diffraction grating 131 and a plurality (two in this example) of lenses 132 and 133. As will be described later, a part of the light emitted from the light projecting unit 120 and reflected from the surface of the measurement object S is output from the optical fiber 312 of the light guide unit 300. The light output from the optical fiber 312 passes through the lens 132, becomes substantially parallel, and enters the diffraction grating 131. In the present embodiment, the diffraction grating 131 is a reflective diffraction grating. The light incident on the diffraction grating 131 is split so as to be reflected at different angles for each wavelength, and is focused on a one-dimensional position that differs for each wavelength by passing through the lens 133.

  The light receiving unit 140 includes an imaging element (one-dimensional line sensor) in which a plurality of pixels are arranged one-dimensionally. The image pickup device may be a multi-segment PD (photodiode), a CCD (charge coupled device) camera, a CMOS (complementary metal oxide semiconductor) image sensor, or another device. The light receiving unit 140 is arranged such that a plurality of pixels of the image sensor respectively receive light at a plurality of in-focus positions that are different for each wavelength formed by the lens 133 of the spectroscopic unit 130. Each pixel of the light receiving unit 140 outputs an analog electrical signal (hereinafter referred to as a light receiving signal) corresponding to the amount of light received. The light reception signal indicates the intensity of light received by each pixel.

  The arithmetic processing unit 150 includes a storage unit 151 and a control unit 152. The storage unit 151 includes, for example, a ROM (read only memory), a RAM (random access memory), or a hard disk. The storage unit 151 stores a control program for controlling each component in the processing apparatus 100 and a calculation program for calculating displacement, and various data used for displacement measurement. The control unit 152 includes, for example, a CPU (Central Processing Unit).

  The control unit 152 acquires the light reception signal output from the light receiving unit 140, measures the displacement of the measurement object S based on the calculation program and data stored in the storage unit 151, and displays the measurement result on the sub display unit 400. indicate.

  Here, the PC 600 is connected to the arithmetic processing unit 150. The PC 600 includes a CPU (Central Processing Unit) 601 and a memory 602. The memory 602 stores a displacement measurement program and various data used for displacement measurement.

  The control unit 152 of the processing apparatus 100 further gives the light reception signal acquired from the light receiving unit 140 to the CPU 601 of the PC 600. The CPU 601 acquires the light reception signal given from the control unit 152, measures the displacement of the measurement object S based on the displacement measurement program and data stored in the memory 602, and performs various processes relating to the measurement result. . For example, the CPU 601 displays the measurement result value on the display unit 700. Further, the CPU 601 displays the waveform of the received light signal given from the control unit 152 on the display unit 700. Furthermore, the CPU 601 displays statistics about a plurality of measurement results acquired at a plurality of times before the current time on the display unit 700.

  The measurement head 200 includes a housing 210 having a substantially axisymmetric shape (for example, a cylindrical shape), an optical fiber 314, the light irradiation unit 1, and a lens unit 220. The housing 210 accommodates the optical fiber 314, the light irradiation unit 1, and the lens unit 220.

  A fiber connector 330 of the light guide unit 300 described later is attached to one end of the housing 210. The optical fiber 314 is connected to the fiber connector 330 in the housing 210. Light is guided from the processing apparatus 100 to the optical fiber 314 through the light guide unit 300. The light guided to the optical fiber 314 is output from the optical fiber 314 in the housing 210 and guided to the lens unit 220.

  The lens unit 220 includes a refractive lens 221, a diffractive lens 222, and an objective lens 223. The light guided to the lens unit 220 passes through the refractive lens 221 and the diffractive lens 222 in order. As a result, chromatic aberration occurs in the light along the optical axis direction. The light in which the chromatic aberration is generated is guided to the outside of the housing 210 through the objective lens 223 and is irradiated on the measurement object S. The objective lens 223 is arranged so that light with chromatic aberration can be focused at a position near the surface of the measurement object S.

  The light irradiation unit 1 includes, for example, an electric drive mechanism, and shifts the optical axis of light emitted from the measurement head 200 toward the measurement object S in a direction orthogonal to the optical axis. In addition, the light irradiation part 1 should just be able to shift the optical axis of the light irradiated to the measuring object S, and does not need to be provided in the inside of the housing | casing 210. FIG. In this case, the light irradiation unit 1 may be configured to be able to move the housing 210 relative to the measurement target S, for example, or the measurement target S relative to the housing 210. It may be configured to be movable.

  The light irradiation unit 1 of this example is supplied with power from the power supply unit 160 of the processing apparatus 100 via a power cable (not shown). Therefore, there is no need to accommodate a device for supplying power to the light irradiation unit 1 in the casing 210. Thereby, the measurement head 200 can be reduced in size and weight.

  The light guide unit 300 includes a plurality (three in this example) of optical fibers 311, 312, 319, a fiber coupler 320, and a fiber connector 330. In the example of FIG. 1, the fiber coupler 320 is provided in the housing 110 of the processing apparatus 100. The fiber connector 330 is attached to the housing 210 of the measuring head 200 as described above. The present invention is not limited to this, and the fiber coupler 320 may be provided in a portion other than the casing 110 of the processing apparatus 100. Further, the fiber connector 330 may be provided in a part other than the casing 210 of the measuring head 200.

  The fiber coupler 320 has a so-called 1 × 2 configuration and includes three ports 321 to 323 and a main body 324. The ports 321 and 322 and the port 323 are connected to the main body 324 so as to face each other with the main body 324 interposed therebetween. Light input to at least one of the ports 321 and 322 is output from the port 323. Light input to the port 323 is output from each of the ports 321 and 322.

  The fiber connector 330 includes two ports 331 and 332 and a main body 333. The port 331 and the port 332 are connected to the main body 333 so as to face each other with the main body 333 interposed therebetween. Light input to the port 331 is output from the port 332, and light input to the port 332 is output from the port 331.

  Optical ports 311 and 312 are connected to ports 321 and 322 of the fiber coupler 320, respectively. An optical fiber 314 is connected to the port 332 of the fiber connector 330. A port 323 of the fiber coupler 320 and a port 331 of the fiber connector 330 are connected by an optical fiber 319.

  According to this configuration, the light emitted from the light projecting unit 120 of the processing apparatus 100 is input to the port 321 of the fiber coupler 320 through the optical fiber 311. The light input to the port 321 is output from the port 323 and input to the port 331 of the fiber connector 330 through the optical fiber 319. The light input to the port 331 is output from the port 332 and irradiated onto the measurement object S through the optical fiber 314 and the lens unit 220.

  A part of the light reflected by the surface of the measuring object S is input to the port 332 of the fiber connector 330 through the lens unit 220 and the optical fiber 314. The light input to the port 332 is output from the port 331 and input to the port 323 of the fiber coupler 320 through the optical fiber 319. Light input to the port 323 is output from the ports 321 and 322. The light output from the port 322 is guided to the spectroscopic unit 130 through the optical fiber 312. Thereby, a displacement measurement process is performed.

  The main display unit 700 includes a display device such as an organic EL (electroluminescence) panel or a liquid crystal display panel. The operation unit 800 includes a keyboard and a pointing device. The pointing device includes a mouse or a joystick. Main display unit 700 and operation unit 800 are connected to PC 600. As described above, the main display unit 700 displays, for example, the value of the displacement measurement result or the waveform of the received light signal. By operating the operation unit 800, the user can operate various buttons displayed on the main display unit 700 and input desired information regarding displacement measurement, for example.

  FIG. 2 is a display example of values of measurement results on the main display unit 700. FIG. 3 is a display example of the waveform of the received light signal on the main display unit 700.

  In the example of FIG. 2, a numerical value indicating the displacement measurement result is displayed on the main display unit 700 and a switching button 491 is displayed. In the example of FIG. 3, the main display unit 700 displays the waveform of the received light signal acquired at the present time, and also displays a switching button 491. In the graph showing the waveform of the light reception signal in FIG. 3, the horizontal axis indicates the wavelength of the received light, and the vertical axis indicates the intensity of the light reception signal.

  The user can switch the display state of the main display unit 700 to the display state of the received light waveform of FIG. 3 by operating the switch button 491 of FIG. 2 using the operation unit 800 of FIG. Further, the user switches the display state of the main display unit 700 to the display state of the measurement result value by the numerical value of FIG. 2 by operating the switch button 491 of FIG. 3 using the operation unit 800 of FIG. Can do.

  The PC 600 is further configured to be connectable to an external device (not shown) such as a programmable controller, and can transmit a displacement measurement result and a light reception signal to the external device.

  A reference range for quality determination with respect to the measurement distance of the measurement object S may be set in the PC 600. In this case, when the measurement distance is within the reference range, a determination result (for example, “OK”) indicating that the measurement object S is a non-defective product is displayed on the main display unit 700. On the other hand, when the measurement distance is outside the reference range, a determination result (for example, “NG”) indicating that the measurement object S indicates a defective product is displayed on the main display unit 700.

(2) Operation Principle of Confocal Displacement Meter FIG. 4 is a diagram for explaining the operation principle of the confocal displacement meter 500 using the measurement head 200. As shown in FIG. 4, the optical fiber 314 includes a core 310a and a clad 310b. The core 310a is covered with a clad 310b. The light input to one end of the core 310a is output from the other end of the core 310a. Note that the optical fibers 311, 312, and 319 of FIG. 1 have the same configuration as the optical fiber 314. The diameter of the core 310a is preferably 200 μm or less, and more preferably 50 μm or less.

  The light output from the optical fiber 314 passes through the refractive lens 221 and the diffractive lens 222. Thereby, chromatic aberration occurs in the light. The light in which chromatic aberration has occurred passes through the objective lens 223 and is focused at a different position for each wavelength. For example, light having a short wavelength is focused at a position close to the objective lens 223, and light having a long wavelength is focused at a position far from the objective lens 223. A range between the in-focus position P1 closest to the objective lens 223 and the in-focus position P2 farthest from the objective lens 223 is the measurement range MR. In this example, the refractive lens 221 has a convex shape, and the diffractive lens 222 has a concave shape. In this case, chromatic aberration generated in the light is increased. Thereby, the measurement range MR can be enlarged.

  When the surface of the measurement object S exists in the measurement range MR, the light that has passed through the objective lens 223 is irradiated on the surface of the measurement object S and then reflected by the surface over a wide range. Here, in the present embodiment, the tip portion of the optical fiber 314 functions as a spatial filter having a minute pinhole. Therefore, most of the light reflected by the surface of the measuring object S is not input to the optical fiber 314.

  On the other hand, light having a specific wavelength focused at the position of the surface of the measurement object S is reflected by the surface, passes through the lens unit 220, and is input to the tip portion of the core 310a of the optical fiber 314. . The wavelength of the light input to the optical fiber 314 indicates the measurement distance. Here, the measurement distance is a distance from a predetermined reference position RP to the position of the surface of the measurement object S. In this example, the reference position RP is the position of the end of the casing 210 that is closest to the measurement object S.

  The light input to the optical fiber 314 is guided to the processing apparatus 100 of FIG. 1, is dispersed by the diffraction grating 131 and is focused at a different position for each wavelength by the lens 133. The plurality of pixels of the light receiving unit 140 are respectively arranged at the in-focus positions of a plurality of lights that differ for each wavelength. Therefore, each pixel of the light receiving unit 140 receives light having a wavelength associated with the pixel and outputs a light reception signal.

  According to this configuration, the wavelength of the received light can be specified by specifying the position of the pixel of the light receiving unit 140 that outputs the light reception signal. Further, the measurement distance can be specified by specifying the wavelength of the received light. However, light to be focused at a position different from the position of the surface of the measurement object S may be input to the optical fiber 314 due to irregular reflection of light on the surface of the measurement object S. In this case, a measurement error with a degree larger than the roughness of the surface of the measurement object S occurs at the measurement distance specified by the processing apparatus 100.

  In the confocal displacement meter 500 according to the present embodiment, the light irradiation unit 1 shifts the optical axis of the light irradiated toward the measurement object S in a direction orthogonal to the optical axis. In this case, light is irradiated to a plurality of regions on the surface of the measurement object S. Hereinafter, an area irradiated with light from the measurement head 200 on the surface of the measurement object S is referred to as an irradiation area. Each time the optical axis is shifted, the light focused at the position of the irradiation region passes through the lens unit 220 and is input to the core 310 a of the optical fiber 314 and received by the light receiving unit 140.

  FIG. 5 is a diagram showing the relationship between the wavelength of the light received by the light receiving unit 140 and the intensity of the received light signal. The horizontal axis in FIG. 5 indicates the wavelength of the received light, and the vertical axis indicates the intensity of the received light signal. The same applies to FIGS. 8 to 10 and FIG. 12 described later. The horizontal axis of FIG. 5 and FIGS. 8 to 10 and FIG. 12 described later corresponds to the pixel position of the light receiving unit 140.

  In this example, the light irradiation part 1 is an optical axis of the light irradiated from the measurement head 200 toward the measurement target S so that four different parts of the surface of the measurement target S are sequentially irradiated with light. Shift. In FIG. 5, waveforms of received light signals (hereinafter referred to as received light waveforms) W <b> 1 to W <b> 4 corresponding to light input to the optical fiber 314 when light is irradiated on four portions of the surface of the measurement object S. Are indicated by a dotted line, a one-dot chain line, a two-dot chain line and a broken line, respectively. The peak wavelengths of the received light waveforms W1 to W4 (hereinafter referred to as peak wavelengths) are λ1 to λ4, respectively. Peak wavelengths λ1 to λ4 of the plurality of received light waveforms W1 to W4 are different from each other due to irregular reflection on the surface of the measurement object S.

  Therefore, the light receiving unit 140 performs exposure during a period in which light is irradiated to a plurality of portions of the irradiation region on the surface of the measurement target S. After light is irradiated to a plurality of portions of the irradiation region, a light reception signal integrated over the entire exposure period is output from each pixel of the light receiving unit 140. Thereby, the received light signal output from the light receiving unit 140 is subjected to intensity averaging processing. The averaging process in the first embodiment is an average signal corresponding to the average of the intensities for each wavelength for a plurality of lights reflected by a plurality of portions of the irradiation region of the measurement object S and sequentially passing through the pinholes. Means the process of generating. In this example, the averaging process is an integration process. In FIG. 5, the light reception waveform W0 after the averaging process output from the light receiving unit 140 is indicated by a solid line. The peak wavelength of the received light waveform W0 is λ0.

  In this way, by optically averaging the received light waveform W0, a light component that causes a random measurement error due to irregular reflection is canceled out. Therefore, the peak wavelength λ0 is closer to the peak wavelength corresponding to the true measurement distance than the peak wavelengths λ1 to λ4. Here, the true measurement distance is a measurement distance that should be specified when light irregular reflection does not occur. Therefore, the measurement distance can be specified more accurately by specifying the peak wavelength λ0 of the received light waveform W0.

(3) Projecting Unit FIGS. 6A and 6B are a plan view and a cross-sectional view showing the configuration of the projecting unit 120, respectively. As shown in FIGS. 6A and 6B, the light projecting unit 120 includes a light source 121, a phosphor 122, a ferrule 123, a lens 124, a holder 125, a filter element 126, and an element holder 127. The element holder 127 includes a light source fixing part 127A, a ferrule fixing part 127B, and a lens fixing part 127C. The light source 121, the ferrule 123, and the lens 124 are respectively fixed to the light source fixing portion 127A, the ferrule fixing portion 127B, and the lens fixing portion 127C of the element holder 127.

  The light source 121 is a laser diode that emits light having a single wavelength. In the present embodiment, the light source 121 emits blue or ultraviolet light having a wavelength of 450 nm or less. The phosphor 122 absorbs excitation light in the blue region or ultraviolet region and emits fluorescence in a wavelength region different from the wavelength region of the excitation light.

  The fluorescence emitted from the phosphor 122 of this example has a wider range of wavelengths than the excitation light. That is, the fluorescence emitted from the phosphor 122 has a plurality of wavelengths. The phosphor 122 may emit yellow region fluorescence, green region fluorescence, or red region fluorescence. The phosphor 122 may be composed of a plurality of fluorescent members.

  The ferrule 123 holds the end of the optical fiber 311 of the light guide unit 300 in FIG. The lens 124 is disposed between the light source 121 and the ferrule 123. One end face of an annular holder 125 is attached to the end of the ferrule 123 (optical fiber 311). The phosphor 122 is accommodated in the inner periphery of the holder 125. A filter element 126 is attached to the other end surface of the holder 125 so as to cover the phosphor 122 in the holder 125. The filter element 126 is a reflective filter that reflects light in the yellow region, green region, or red region and transmits light in the blue region or ultraviolet region.

  According to this configuration, the light emitted from the light source 121 passes through the lens 124 and is condensed on the phosphor 122 as excitation light. The phosphor 122 absorbs excitation light and emits fluorescence. Here, the excitation light that is transmitted without being absorbed by the phosphor 122 and the fluorescence from the phosphor 122 are mixed, thereby generating light in a wide wavelength band. In this example, in order to generate light in which excitation light and fluorescence are mixed in a desired ratio, the thickness of the phosphor 122 in the optical path direction is formed to be 10 μm to 200 μm, for example. Moreover, the density | concentration of the fluorescent substance 122 in the holder 125 is formed in 30%-60%, for example.

  The light generated in the light projecting unit 120 is input to the optical fiber 311 by passing through the ferrule 123. The fluorescence emitted by the phosphor 122 in the direction opposite to the optical fiber 311 is reflected by the filter element 126 in the direction of the optical fiber 311. Thereby, fluorescence can be efficiently input into the optical fiber 311.

  In this example, the phosphor 122 is accommodated in the holder 125, but the present invention is not limited to this. The phosphor 122 may be applied to the end face of the ferrule 123. In this case, the light projecting unit 120 does not include the holder 125. Moreover, although the light projection part 120 contains the filter element 126, this invention is not limited to this. When sufficient fluorescence is input to the optical fiber 311, the light projecting unit 120 may not include the filter element 126.

(4) Arithmetic Processing Unit In the storage unit 151 of the arithmetic processing unit 150 in FIG. 1, the conversion formula of the pixel position of the light receiving unit 140, the peak wavelength λ0 of the received light reception waveform W0, and the measurement distance is as described above. Pre-stored with the calculation program. The control unit 152 of the arithmetic processing unit 150 specifies the position of the pixel that outputs the light reception signal, and based on the position of the specified pixel and the conversion formula stored in the storage unit 151, the peak wavelength λ0 of the light reception waveform W0 and The measurement distance is sequentially calculated, and the calculated measurement distance is displayed on the sub display unit 400. Thereby, the thickness, distance, or displacement of the measuring object S can be measured. In addition, the control unit 152 performs unnecessary component removal correction, light reception waveform shift correction, and light reception waveform scale correction described below in order to calculate the measurement distance more accurately.

(A) Unnecessary component removal correction Light different from the light reflected while focusing on the surface of the measurement object S may be received by the light receiving unit 140. In the following description, light excluding light reflected by the light receiving unit 140 while being focused on the surface of the measurement object S is referred to as unnecessary light.

  FIG. 7 is a schematic diagram illustrating an example of unnecessary light reflected by a portion different from the measurement object S. 7, illustration of the light irradiation part 1 of FIG. 1 is abbreviate | omitted. In the example of FIG. 7, light directly reflected by the refractive lens 221 of the lens unit 220 (light indicated by an arrow) is input to the optical fiber 314. The received light waveform W0 corresponding to such light does not include a component indicating the measurement distance, but includes an unnecessary component.

  FIG. 8 is a diagram showing a received light waveform W0 including unnecessary components. The received light waveform W0 in FIG. 8 includes three peaks P0, Px, and Py. The peak P0 is generated by the light reflected while being focused on the surface of the measurement object S. The peak P0 has a steep shape, and the peak wavelength is λ0. The peak Px includes, for example, a component corresponding to unnecessary light in FIG. 7 and is generated by light reflected from a portion different from the measurement target S. The peak Px has a smooth shape, and the peak wavelength is λx. The peak Py is generated by light from the light source 121 (FIG. 6) having the oscillation wavelength λy. More specifically, the peak Py is generated by the light source 121 (FIG. 6) and guided to the surface of the measurement object S while passing through the phosphor 122 (FIG. 6). It is generated by unnecessary light reflected without being burned. The peak Py has a steep shape, and the peak wavelength is λy.

  The peak wavelength λx is relatively close to the peak wavelength λ0, and the width of the peak Px is wide. Therefore, the peak P0 is buried in the peak Px. In this case, it is difficult to accurately specify the peak wavelength λ0. Therefore, unnecessary component removal correction is performed to remove a portion resulting from the peak Px (hereinafter referred to as the base waveform BL) from the received light waveform W0 as an unnecessary component.

  FIG. 9 is a diagram illustrating the base waveform BL of the light reception waveform W0. In the present embodiment, the control unit 152 obtains the base waveform BL of FIG. 9 by applying a low-pass filter process for identifying the peak Px and the peak P0 to the received light waveform W0. The method of acquiring the base waveform BL is not limited to the above method, and data indicating the base waveform BL may be stored in advance in the storage unit 151 of FIG. In this case, the control unit 152 corrects the light reception waveform W0 so as to remove the base waveform BL from the light reception waveform W0 of FIG. 8 based on the acquired base waveform BL of FIG.

  FIG. 10 is a diagram illustrating the light reception waveform W0 from which the base waveform BL is removed. In the example of FIG. 10, the peak wavelength λ0 is slightly shifted to the shorter wavelength side than the peak wavelength λ0 of FIG. Thus, by removing the base waveform BL from the received light waveform W0, the peak wavelength λ0 can be specified more accurately. As a result, the measurement distance can be calculated more accurately.

  Here, the portion resulting from the peak Py of the received light waveform W0 in FIG. 8 does not affect the accurate identification of the peak wavelength λ0. Therefore, in the unnecessary component removal correction, the portion caused by the peak Py of the light reception waveform W0 may not be removed from the light reception waveform W0 or may be removed from the light reception waveform W0. When the part caused by the peak Py is close to the wavelength range corresponding to the measurement range MR (FIG. 4), it is preferable to remove the part caused by the peak Py of the received light waveform W0 from the received light waveform W0 together with the base waveform BL. .

  In the present embodiment, since the intensity of the excitation light emitted from the light source 121 made of a laser diode is excessively large with respect to the intensity suitable for the displacement measurement, light having a wavelength component corresponding to the excitation light is unnecessary light. It is said. Therefore, the excitation light may be used for displacement measurement as long as the intensity of the excitation light emitted from the light source 121 is within a range suitable for displacement measurement.

  Still another example of unnecessary light will be described. FIG. 11 is a diagram illustrating a path of light guided to the light receiving unit 140. As shown in FIG. 11, in addition to the first-order light split by the diffraction grating 131, zero-order light that has been zero-order diffracted (regular reflection in this example) is guided to the light receiving unit 140. In FIG. 11, primary light is indicated by a solid line, and zero-order light is indicated by a one-dot chain line.

  FIG. 12 is a diagram showing a light reception waveform W0 of light guided to the light receiving unit 140 of FIG. As shown in FIG. 12, the received light waveform W0 includes a portion corresponding to the primary light and a portion corresponding to the zero-order light. Similar to the light reception waveform W0 of FIG. 8, the portion of the light reception waveform W0 corresponding to the primary light includes three peaks P0, Px, and Py. The portion of the received light waveform W0 corresponding to the 0th order light includes one peak Pz.

  The zero-order light is reflected in a certain direction by the diffraction grating 131 regardless of the wavelength. The diffraction grating 131 is arranged so that zero-order light is not received by pixels corresponding to the measurement range MR (FIG. 4). Therefore, the 0th order light is not used for calculation of the measurement distance. As shown in FIG. 12, when the received light waveform W0 includes a zero-order light component as unnecessary light, in the unnecessary component removal correction, the portion caused by the peak Pz of the received light waveform W0 is not removed from the received light waveform W0. Alternatively, it may be removed from the received light waveform W0.

(B) Light reception waveform shift correction and light reception waveform scale correction In the following description, as described in the example of FIG. 7, the light is emitted from the light projecting unit 120 and reflected by the lens unit 220 to be received by the light receiving unit 140. The unnecessary light is referred to as first unnecessary light. Further, unnecessary light generated by the light source 121 and guided to the surface of the measurement object S while passing through the phosphor 122 and reflected by the light reception unit 140 without being focused on the surface of the measurement object S. This is called second unnecessary light. Furthermore, as described in the example of FIG. 11, the 0th-order light generated by the diffraction grating 131 and received by the light receiving unit 140 is referred to as third unnecessary light.

  As described above, light having a specific wavelength is received by the pixels of the light receiving unit 140 associated with the wavelength. However, due to a change in the position of the light receiving surface of the light receiving unit 140 or a change in the tilt of the light receiving surface due to a change in ambient temperature, light having a specific wavelength may be received by a pixel different from the pixels associated in advance. is there. In this case, the measurement distance cannot be accurately calculated because the measurement result varies with the temperature change. Therefore, light reception waveform shift correction and light reception waveform scale correction described below are performed. The received light waveform shift correction is a process for correcting a shift on the wavelength axis of the received light waveform W0 depending on temperature. The received light waveform scale correction is a process of correcting the scale on the wavelength axis of the received light waveform W0 depending on temperature.

  For example, as shown in FIG. 12, the received light waveform W0 when measuring the displacement of the measuring object S includes peaks P0 depending on the displacement of the measuring object S and peaks corresponding to the first to third unnecessary lights, respectively. Px, Py, Pz are included.

  The peak Px does not depend on the displacement of the measurement target S because the first unnecessary light does not reach the measurement target S. The peak Py does not depend on the displacement of the measurement object S because the second unnecessary light has the oscillation wavelength λy of the light source 121. The peak Pz does not depend on the displacement of the measurement target S because the third unnecessary light is received by a specific pixel of the light receiving unit 140 regardless of the wavelength. In the light reception waveform shift correction, at least one of the three peaks Px, Py, and Pz is used. In the light reception waveform scale correction, at least two of the three peaks Px, Py, and Pz are used.

  In order to perform the light reception waveform shift correction, the storage unit 151 in FIG. 1 stores in advance a wavelength at which at least one peak center among the peaks Px, Py, and Pz should appear as a reference wavelength. The control unit 152 identifies the wavelengths of the peaks Px to Pz corresponding to the reference wavelength stored in the storage unit 151. The control unit 152 calculates the shift amount on the wavelength axis of the received light waveform W0 by comparing the wavelengths of the specified peaks Px to Pz and the reference wavelength, and the wavelength of the received light waveform W0 based on the calculated shift amount. Correct the shift on the axis. In FIG. 12, the light reception waveform W0 after the shift of the light reception waveform W0 on the wavelength axis is corrected is indicated by a dotted line.

  In order to perform the light reception waveform scale correction, the storage unit 151 stores in advance a wavelength interval at which the centers of at least two peaks Px, Py, and Pz should appear as a reference interval. The control unit 152 identifies the interval between the peaks Px to Pz corresponding to the reference interval stored in the storage unit 151. The control unit 152 calculates the deviation of the scale on the wavelength axis of the received light waveform W0 by comparing the interval between the specified peaks Px to Pz and the reference interval, and based on the calculated deviation of the scale, the received light waveform W0. Correct the scale on the wavelength axis.

  As the correction related to the temperature characteristics of the light receiving unit 140, only one of the light reception waveform shift correction and the light reception waveform scale correction may be performed, or both may be performed. The light reception waveform shift correction and the light reception waveform scale correction are performed before the unnecessary component removal correction. By specifying the peak P0 of the light reception waveform W0 after the light reception waveform shift correction and the light reception waveform scale correction are performed, the measurement distance can be calculated more accurately.

  The received light signal subjected to the unnecessary component removal correction, the received light waveform shift correction, and the received light waveform scale correction in the control unit 152 is given to the PC 600. In this case, the CPU 601 can measure the displacement based on the appropriately received light signal.

(5) Effect In the confocal displacement meter 500 according to the present embodiment, light having a plurality of wavelengths is emitted by the light projecting unit 120. The light emitted from the light projecting unit 120 is sequentially irradiated onto a plurality of portions of the measurement object S by the light irradiation unit 1 in the measurement head 200. Chromatic aberration along the optical axis direction is generated by the lens unit 220 in the light irradiated onto the measurement object S by the light irradiation unit 1. The light having chromatic aberration is converged by the lens unit 220.

  Light having a wavelength reflected while being focused on a plurality of portions on the surface of the measurement object S sequentially passes through the core 310a of the optical fiber 314. A plurality of light beams that have passed through the optical fiber 314 sequentially are sequentially guided to the spectroscopic unit 130 through the fiber connector 330, the optical fiber 319, the fiber coupler 320, and the optical fiber 312, and are dispersed. The plurality of lights dispersed by the spectroscopic unit 130 are received by the light receiving unit 140 during a period in which the plurality of portions on the surface of the measurement target S are irradiated with light. Therefore, the electrical light reception signal indicating the light reception amount for each wavelength output from the light receiving unit 140 is an average signal obtained by integrating the intensities for each wavelength for a plurality of lights respectively corresponding to the plurality of portions. Thereby, the averaging process of a plurality of lights can be easily performed. Based on the light intensity after the averaging process, the controller 152 calculates the displacement of the measurement object S.

  Due to irregular reflection on the surface of the measurement object S, light focused at a position different from the position of the surface of the measurement object S may pass through the optical fiber 314. Even in such a case, according to said structure, the intensity | strength for every wavelength about the some light which passed the optical fiber 314 in the averaging process is averaged. As a result, a light component that causes a random measurement error due to irregular reflection is canceled out. Further, in the above configuration, before calculating the displacement of the measurement object S, unnecessary light components including at least the base waveform BL are removed from the received light waveform W0 by unnecessary component removal correction. As a result, the displacement error of the measurement object S measured by the confocal displacement meter 500 can be reduced.

  In the above configuration, the received light waveform shift correction is performed before the unnecessary component removal correction. As the received light waveform shift correction, the received light waveform W0 that depends on the temperature based on at least one of the peaks Px, Py, and Pz corresponding to the first to third unnecessary lights that do not depend on the displacement of the measurement object S, respectively. The shift on the wavelength axis is corrected. As a result, it is possible to compensate for fluctuations in the measurement result due to the shift of the received light waveform W0 on the wavelength axis as the temperature changes.

  Further, in the above configuration, the received light waveform scale correction is performed before the unnecessary component removal correction. As the light reception waveform scale correction, the light reception waveform W0 that depends on the temperature based on at least two of the peaks Px, Py, and Pz corresponding to the first to third unnecessary lights that do not depend on the displacement of the measurement object S, respectively. The scale on the wavelength axis is corrected. As a result, it is possible to compensate for variations in the measurement result due to a deviation of the scale on the wavelength axis of the received light waveform W0 accompanying a temperature change.

  Further, in the above configuration, since it is not necessary to perform an operation for performing the averaging process, the displacement of the measuring object S can be calculated efficiently.

  In the present embodiment, the tip portion of the optical fiber 314 functions as a pinhole. In this case, it is not necessary to arrange the pinhole separately. Thereby, the structure of the confocal displacement meter 500 can be made compact. Thus, by using the clad 310b of the optical fiber 314 as a light shielding part and the core 310a as a pinhole, a confocal optical system can be realized with a simple configuration. On the other hand, if light loss can be tolerated, a light shielding member provided with a pinhole in a light shielding plate may be disposed at the end of the optical fiber 314 on the measurement head 200 side.

  Further, in the present embodiment, the processing apparatus 100 and the measurement head 200 are provided separately and are optically connected by the light guide unit 300. Therefore, it becomes easy to use the measurement head 200 including the lens unit 220 that generates an appropriate chromatic aberration or the lens unit 220 having an appropriate focal length according to the shape or arrangement of the measurement object S. Thereby, the displacement of the measuring object S can be measured more easily.

  Moreover, when the light guide unit 300 includes an optical fiber, the processing device 100 and the measurement head 200 can be arranged separately. The measuring head 200 has no heat source. Therefore, the measurement head 200 can be arranged in various environments. Further, as will be described later, by forming the exposed portion of the measurement head 200 with glass, the measurement head 200 can be arranged in more various environments.

  As described above, in the light projecting unit 120, a part of light emitted from the light source 121 formed of a laser diode is absorbed by the phosphor 122. Thereby, light having a plurality of wavelengths is generated from the phosphor 122. The generated light is applied to the measurement object S while generating chromatic aberration through the lens unit 220. Thereby, it is possible to easily generate light of a plurality of wavelengths for measuring the displacement of the measuring object S.

  When a laser diode is used as the light source 121, the light guide unit 300 preferably includes an optical fiber. For example, as shown in FIG. 6, when the phosphor 122 is excited by the laser light emitted from the light source 121 to generate light having a plurality of wavelengths, the light generated by using the optical fiber is efficiently used. Can be extracted well. Further, by using the optical fiber, the extracted light can be efficiently supplied to the measuring head 200.

  Further, in the light projecting unit 120, the light emitted from the light source 121 is condensed on the phosphor 122 by passing through the lens 124. As a result, the amount of light incident on the phosphor 122 can be increased. Thereby, the light quantity of the light of the several wavelength radiate | emitted from the fluorescent substance 122 to the lens unit 220 increases. Therefore, even when the size of the irradiation region formed on the surface of the measurement object S is reduced, the amount of light passing through the core 310a of the optical fiber 314 is prevented from being significantly reduced. Accordingly, the size of the irradiation area can be reduced.

  As described above, the lens unit 220 includes the refractive lens 221 having a convex shape and the diffractive lens 222 having a concave shape. The refractive lens 221 and the diffractive lens 222 are arranged so that the light output from the optical fiber 314 passes through the refractive lens 221 and the diffractive lens 222. In this case, the direction of chromatic aberration generated by the refractive lens 221 and the diffractive lens 222 is the same in each lens. As a result, the chromatic aberration on the optical axis of the lens unit 220 is increased. Therefore, the measurement range MR of the confocal displacement meter 500 can be increased.

(6) Specific Configuration of Light Irradiation Unit FIG. 13 is a schematic diagram showing a more specific configuration of the confocal displacement meter 500 of FIG. In the confocal displacement meter 500 of FIG. 13, a flat plate member 230 and a drive unit 240 are provided inside the housing 210 of the measurement head 200 as the light irradiation unit 1 of FIG. 1.

  The flat plate member 230 is formed of a flat plate member having transparency. The flat plate member 230 may be, for example, flat glass, a lens element, or another element. The drive part 240 is a hollow motor, for example. Power is supplied to the drive unit 240 from the power supply unit 160 of the processing apparatus 100 via a power cable (not shown).

  FIG. 14 is a diagram for explaining the operation principle of the confocal displacement meter 500 using the measurement head 200 of FIG. As shown in FIG. 14, the drive unit 240 includes a cylindrical fixing unit 241 and a cylindrical rotating shaft 242. The rotating shaft 242 is provided in the hollow portion of the fixed portion 241 so as to be concentric with the fixed portion 241.

  The end portion of the optical fiber 314 is fixed to the hollow portion of the rotating shaft 242 while being inserted into a ferrule (not shown), for example. The flat plate member 230 is attached to the rotation shaft 242 in a state where the incident surface 231 and the emission surface 232 are inclined with respect to the surface orthogonal to the optical axis of the optical fiber 314. The rotating shaft 242 rotates in a state where light is emitted from the optical fiber 314. The rotational speed of the drive unit 240 is preferably 100 rpm or more, and more preferably 6000 rpm or more. The driving unit 240 rotates continuously, but the present invention is not limited to this. The drive unit 240 may rotate intermittently.

  FIG. 15 is a diagram illustrating an optical path of light when the driving unit 240 in FIG. 14 is rotated. FIG. 15A shows an optical path of light at the initial time point. FIG. 15B shows an optical path of light at a time when a certain time has elapsed from the initial time (when the drive unit 240 has rotated 90 degrees from the initial time). FIG. 15C shows an optical path of light at a time when a certain time has elapsed from the time of FIG. 15B (when the drive unit 240 is further rotated 90 degrees from the time of FIG. 15B).

  As shown in FIGS. 15A to 15C, the light output from the optical fiber 314 is incident on the incident surface 231 of the flat plate member 230 substantially parallel to the optical axis of the optical fiber 314. Since the incident surface 231 of the flat plate member 230 is inclined with respect to a plane orthogonal to the optical axis of the optical fiber 314, the light incident on the incident surface 231 of the flat plate member 230 is inclined at an angle with respect to the incident angle. The light passes through the flat plate member 230. Thereafter, the light is emitted from the emission surface 232 of the flat plate member 230 at an angle substantially equal to the incident angle. Thereby, it is possible to irradiate the measurement object S with light through the lens unit 220 of FIG. 14 while shifting the optical axis of the light.

  FIG. 16 is a diagram illustrating a region of the measurement object S irradiated with light by the measurement head 200 of FIG. As shown in FIG. 16, light is irradiated to an annular region on the surface of the measurement object S. Thus, an annular irradiation region IR is formed on the surface of the measuring object S. According to this structure, compared with the case where light is irradiated to the linear area | region of the surface of the measuring object S, the burden of the physical operation | movement part of the light irradiation part 1 is small. Thereby, the lifetime of the flat plate member 230 and the drive part 240 can be prolonged. By selecting the inclination angle, thickness, refractive index, and the like of the flat plate member 230, the outer diameter OD of the irradiation region IR can be determined. In this example, the outer diameter OD is, for example, 250 μm. Thus, since the outer diameter OD is small, the user recognizes the irradiation region IR as one point instead of an annular shape.

  Of the light reflected by the irradiation region IR of the measurement object S, the light focused at the position of the irradiation region IR passes through the lens unit 220 and the flat plate member 230 and is input to the optical fiber 314 and received by the light receiving unit 140. Is done.

  Light is irradiated to a plurality of different portions of the measuring object S at a plurality of different points in the period in which the drive unit 240 rotates once. Thereby, at a plurality of time points, for example, a plurality of received light waveforms W1 to W4 as shown in FIG. 5 can be acquired. Therefore, the light receiving unit 140 performs exposure during a period in which the driving unit 240 rotates once. In this example, the light receiving unit 140 continuously exposes, but the present invention is not limited to this. The light receiving unit 140 may perform exposure intermittently.

  After the drive unit 240 makes one rotation, a light reception signal integrated during the exposure period is output from each pixel of the light reception unit 140. Thereby, the received light signal output from the light receiving unit 140 is subjected to intensity averaging processing. As a result, the light reception waveform W0 of FIG. 5 is obtained. Therefore, the measurement distance can be specified more accurately by specifying the peak wavelength λ0 of the received light waveform W0.

  The outer diameter OD of the irradiation region IR is preferably 100 μm or more. In this case, light is reflected at a plurality of portions in a sufficiently large region on the surface of the measurement object S. Therefore, the light component that causes a random measurement error due to irregular reflection is sufficiently canceled out in the signal of the average distribution. Thereby, the error of the displacement of the measuring object S measured by the confocal displacement meter 500 can be further reduced.

  Further, the outer diameter OD of the irradiation region IR is preferably 500 μm or less. In this case, since the light irradiated to the measurement object S by the light irradiation unit 1 does not spread excessively large, it can pass near the center of the lens unit 220. Therefore, almost no aberration such as coma that lowers the measurement accuracy occurs. Thereby, the displacement of the measuring object S can be measured with higher accuracy.

  As described above, the light receiving unit 140 receives light during a single exposure period during which the drive unit 240 rotates once. Thereafter, a light reception signal is output from the light receiving unit 140. Thereby, since it is not necessary to perform an operation for performing the averaging process, the displacement of the measurement object S can be calculated efficiently.

(7) Modified Example of Lens Unit In the present embodiment, the lens unit 220 includes the refractive lens 221 and the diffractive lens 222, but the present invention is not limited to this. The lens unit 220 may not include one or both of the refractive lens 221 and the diffractive lens 222. FIGS. 17A to 17D are views showing first to fourth modifications of the lens unit 220. FIG.

  As shown in FIG. 17A, the lens unit 220 in the first modification includes the diffractive lens 222 and the objective lens 223 without including the refractive lens 221 of FIG. As shown in FIG. 17B, the lens unit 220 in the second modified example includes the diffractive lens 222 and the objective lens 223 instead of the refractive lens 221 in FIG. 1 as in the first modified example. In the second modification, the diffractive lens 222 and the objective lens 223 are disposed in the opposite positions to the positions of the diffractive lens 222 and the objective lens 223 in the first modification.

  As shown in FIG. 17C, the lens unit 220 in the third modified example includes a doublet lens 224 instead of the diffractive lens 222 in the first modified example. As shown in FIG. 17D, the lens unit 220 in the fourth modified example includes a doublet lens 224 in place of the diffractive lens 222 in the second modified example. As described above, the lens unit 220 may be configured by, for example, a diffractive lens, a doublet lens, a GRIN (graded index) lens, a prism, or a combination thereof. According to the configuration of these lens units 220, chromatic aberration along the optical axis direction is generated in the light emitted from the light projecting unit 120, and the light having chromatic aberration is converged to irradiate the measurement object S. it can.

  The lens described above may be a glass lens, a resin lens, or a glass lens whose surface is coated with a resin. The glass lens has high heat resistance. The resin lens can be manufactured at low cost. A glass lens coated with a resin can be manufactured at a relatively low cost and has a relatively high heat resistance.

  Among the lens units 220, the lens that can be brought closest to the measuring object S is disposed, for example, in a state of being exposed to the outside. Thus, the lens exposed to the outside is preferably formed of glass. In a production line such as a factory, the measuring head 200 is disposed in an environment where moisture or oil is present. By forming the optical system of the portion exposed to the outside of the measuring head 200 from glass, the oil resistance, water resistance, and contamination resistance of the measuring head 200 can be improved.

  For the same reason as in the above example, when the lens unit 220 has a portion exposed to the outside, the exposed portion is preferably formed of glass. If the entire lens unit 220 can be shielded from the atmosphere outside the measuring head 200, the refractive lens 221, the diffractive lens 222, the objective lens 223, or the doublet lens 224 are formed of resin instead of glass. Also good. For example, in the example of FIGS. 17A to 17D, a cover glass is provided on the lower side (measurement object S side) of the lens unit 220 in a state where the lens unit 220 is disposed in the housing 210. May be.

(8) Modified Example of Projecting Unit In the present embodiment, the optical axis of the light emitted from the light source 121 and the central axis of the ferrule 123 are arranged on a straight line, but the present invention is not limited to this. FIG. 18 is a diagram illustrating a modification of the light projecting unit 120. As illustrated in FIG. 18, the light projecting unit 120 in the modification includes a light source 121, a phosphor 122, a ferrule 123, lenses 124 and 128, and a reflecting member 129. The lens 124 is disposed between the light source 121 and the reflecting member 129. The lens 128 is disposed between the reflecting member 129 and the ferrule 123. The phosphor 122 is applied to the reflecting surface of the reflecting member 129.

  The light emitted from the light source 121 passes through the lens 124 and is condensed on the phosphor 122 applied to the reflecting member 129 as excitation light. The phosphor 122 absorbs excitation light and emits fluorescence. Here, the excitation light that is transmitted without being absorbed by the phosphor 122 and the fluorescence from the phosphor 122 are mixed, thereby generating light in a wide wavelength band. The generated light is reflected by the reflecting surface of the reflecting member 129 and guided to the ferrule 123 through the lens 128. As a result, light is input to the optical fiber 311. In this configuration, the degree of freedom of arrangement of the optical elements is increased. Therefore, it becomes easy to reduce the size of the light projecting unit 120.

  In order to increase the intensity of light generated by the light projecting unit 120, it is preferable to increase the amount of light emitted from the light source 121. On the other hand, when the amount of light from the light source 121 is increased, the heat generation of the phosphor 122 increases, so that the reflection efficiency of the reflecting member 129 is lowered and the emission of fluorescence from the phosphor 122 is easily saturated. Therefore, the reflection member 129 may be configured to be rotatable or movable. Thereby, the phosphor 122 is cooled and heat generation can be suppressed. As a result, the intensity of light generated by the light projecting unit 120 can be further increased.

(9) Modified Example of Spectroscopic Unit In the present embodiment, the diffraction grating 131 of the spectral unit 130 has a reflection type, but the present invention is not limited to this. FIG. 19 is a diagram illustrating a modification of the spectroscopic unit 130. As shown in FIG. 19, in a modification of the spectroscopic unit 130, the diffraction grating 131 has a transmission type. The light incident on the diffraction grating 131 is split so as to be transmitted at different angles for each wavelength. The light dispersed by the diffraction grating 131 passes through the lens 133 and is focused on the pixel position of the light receiving unit 140 that differs for each wavelength.

  In the spectroscopic unit 130 of this example, zero-order light that passes straight through the diffraction grating 131 may be generated. When the 0th-order light is received by the light receiving unit 140, the peak of the received light waveform corresponding to the 0th-order light can be used for the received light waveform shift correction and the received light waveform scale correction.

[2] Second Embodiment (1) Basic Configuration and Operating Principle of Confocal Displacement Meter Regarding the confocal displacement meter according to the second embodiment of the present invention, the confocal displacement according to the first embodiment. Differences from the total 500 will be described. FIG. 20 is a schematic diagram illustrating a configuration of a confocal displacement meter according to the second embodiment. The confocal displacement meter 500 according to the present embodiment is different from the confocal displacement meter 500 according to the first embodiment in the configuration of the measurement head 200 and the light guide unit 300.

  20 includes a plurality (four in this example) of optical fibers 393-396. The light guide unit 300 includes a plurality (four in this example) of optical fibers 391, 392, 397, 398 and a plurality (two in this example) of fiber couplers 340, 350. The fiber coupler 340 is provided in the casing 110 of the processing apparatus 100, and the fiber coupler 350 is provided in the casing 210 of the measurement head 200. The present invention is not limited to this, and the fiber coupler 340 may be provided in a part other than the casing 110 of the processing apparatus 100, and the fiber coupler 350 may be provided in a part other than the casing 210 of the measuring head 200. Good.

  The fiber coupler 340 has a so-called 2 × 2 configuration, and includes four ports 341 to 344 and a main body 345. The ports 341 and 342 and the ports 343 and 344 are connected to the main body 345 so as to face each other with the main body 345 interposed therebetween. Light input to at least one of the ports 341 and 342 is output from each of the ports 343 and 344. Light input to at least one of the ports 343 and 344 is output from each of the ports 341 and 342.

  The fiber coupler 350 has a so-called 2 × 4 configuration and includes six ports 351 to 356 and a main body 357. The ports 351 and 352 and the ports 353 to 356 are connected to the main body 357 so as to face each other with the main body 357 interposed therebetween. Light input to at least one of the ports 351 and 352 is output from each of the ports 353 to 356. Light input to at least one of the ports 353 to 356 is output from each of the ports 351 and 352.

  Optical fibers 391 and 392 are connected to ports 341 and 342 of the fiber coupler 340, respectively. Optical fibers 393 to 396 are connected to ports 353 to 356 of the fiber coupler 350, respectively. The port 343 of the fiber coupler 340 and the port 351 of the fiber coupler 350 are connected by an optical fiber 397. The port 344 of the fiber coupler 340 and the port 352 of the fiber coupler 350 are connected by an optical fiber 398.

  According to this configuration, the light emitted from the light projecting unit 120 of the processing apparatus 100 is input to the port 341 of the fiber coupler 340 through the optical fiber 391. The light input to the port 341 is output from the ports 343 and 344 and input to the ports 351 and 352 of the fiber coupler 350 through the optical fibers 397 and 398. The light input to the ports 351 and 352 is output from the ports 353 to 356 and is applied to the measurement object S through the optical fibers 393 to 396 and the lens unit 220.

  A part of the light reflected by the surface of the measuring object S is input to the ports 353 to 356 of the fiber coupler 350 through the lens unit 220 and the optical fibers 393 to 396. The light input to the ports 353 to 356 is output from the ports 351 and 352 and input to the ports 343 and 344 of the fiber coupler 340 through the optical fibers 397 and 398. Light input to the ports 343 and 344 is output from the ports 341 and 342. The light output from the port 342 is guided to the spectroscopic unit 130 through the optical fiber 392. Thereby, a displacement measurement process is performed.

  FIG. 21 is a diagram for explaining the operation principle of the confocal displacement meter 500 using the measurement head 200 of FIG. In the measurement head 200 of this example, light input from the processing device 100 through the light guide unit 300 is output from each of the four optical fibers 393 to 396. The light output from each of the four optical fibers 393 to 396 passes through the lens unit 220 and is irradiated to four different portions of the surface of the measuring object S while generating chromatic aberration. In this case, four irradiation areas corresponding to the four optical fibers 393 to 396 are formed on the surface of the measuring object S, respectively.

  22 is a cross-sectional view showing the arrangement of the four optical fibers 393 to 396 in FIG. As shown in FIG. 22, in this example, four optical fibers 393 to 396 are integrally held in a state of being bundled by a holding member 302. In the following description, a configuration including the four optical fibers 393 to 396 and the holding member 302 is referred to as a fiber unit 301.

  Each optical fiber 393-396 includes a core 310a and a cladding 310b. The core 310a is covered with a clad 310b. Light input to one end of the core 310a of the optical fibers 393 to 396 is output from the other end of the core 310a. The optical fibers 391, 392, 397, and 398 in FIG. 20 have the same configuration as the optical fibers 393 to 396.

  The fiber unit 301 is disposed so that the center of the axis substantially coincides with the optical axis of the lens unit 220 in FIG. In this case, the optical fibers 393 to 396 of the fiber unit 301 are preferably disposed symmetrically with respect to the optical axis of the lens unit 220. In the example of FIG. 22, the center of the fiber unit 301 is disposed on the optical axis of the optical system 220, and the core 310 a (optical axis) of each of the optical fibers 393 to 396 is symmetric with respect to the optical axis of the lens unit 220. Placed in. In this case, the core 310 a (optical axis) of each of the optical fibers 393 to 396 is separated from the center of the fiber unit 301, that is, the optical axis of the lens unit 220 by substantially the same distance.

  As described above, the core 310a of each of the optical fibers 393 to 396 is disposed at a position substantially equidistant from the optical axis of the lens unit 220, so that the lens unit 220 for generating aberration along the optical axis direction. Optical design can be easily performed. Here, the optical axis not only means the optical axis when the optical axes of the refractive lens 221, the diffractive lens 222, and the objective lens 223 substantially match, but also the refractive lens 221, the diffractive lens 222, and It may mean any one or more optical axes of the objective lens 223.

  In the example of FIG. 22, the optical fibers 393 to 396 are arranged so as to be positioned at four corners of a square. The diameter L1 of each core 310a is preferably 200 μm or less, and more preferably 50 μm or less. In this case, since the four optical fibers 393 to 396 are arranged close to each other, the user recognizes that one portion of the surface of the measurement object S is irradiated with light.

  Of the light reflected by the four portions (irradiation areas) of the surface of the measurement object S, the light focused at the position of the surface of the measurement object S is input to the corresponding optical fibers 393 to 396, and is shown in FIG. Guided to the processor 100. The light guided to the processing apparatus 100 is received by the light receiving unit 140 while being dispersed by the diffraction grating 131. Here, the distance L2 between the centers of adjacent cores 310a is preferably at least three times the diameter L1. When the distance L2 is three times or more than the diameter L1, the light reflected while being focused on a part of the surface of the measurement object S passes through the pinholes of the optical fibers 393 to 396 corresponding to the part, The disturbance light hardly passes through the pinholes of the other optical fibers 393 to 396 that do not correspond to the part.

  More preferably, the distance L2 between the centers of adjacent cores 310a is not less than 5 times and not more than 10 times the diameter L1. When the distance L2 is not less than 5 times and not more than 10 times the diameter L1, the reflected light while focusing on a part of the surface of the measurement object S is not disturbed as another pinhole. Passing is further suppressed. Further, since the plurality of lights are not greatly separated, they can pass near the center of the lens unit 220. Therefore, almost no aberration such as coma that lowers the measurement accuracy occurs. In this example, the diameter L1 is, for example, 50 μm, and the distance L2 is, for example, 250 μm.

  As described above, the light that is reflected while being focused on the four portions of the measurement object S and is input to the optical fibers 393 to 396 passes through the fiber coupler 350, the optical fibers 397 and 398, and the fiber coupler 340 as optical signals. It is mixed in the process until it is output from the optical fiber 392. Thereafter, the mixed optical signal is converted into an electric signal by the light receiving unit 140 through the spectroscopic unit 130. That is, in this example, the averaging process is performed in the state of the optical signal.

  As described above, the intensity averaging process is performed on the optical signal output from the optical fiber 392 while being mixed. The averaging process in the second embodiment means a process of generating an average distribution signal corresponding to the average intensity for each wavelength for a plurality of lights that have passed through a plurality of pinholes. In this example, the averaging process is an integration process.

  Thereby, when the waveform of the light reception signal corresponding to the light reflected while being focused on the four portions of the measurement object S is represented by, for example, the light reception waveforms W1 to W4 in FIG. 5 received light waveforms W0 can be obtained. Therefore, the measurement distance can be specified more accurately by specifying the peak wavelength λ0 of the received light waveform W0.

(2) Effect In the confocal displacement meter 500 according to the present embodiment, the light emitted from the light projecting unit 120 is applied to a plurality of portions of the measurement object S by the plurality of optical fibers 393 to 396 in the measurement head 200. Each is irradiated. Light having a wavelength reflected while being focused in the plurality of irradiation regions of the measurement object S passes through the plurality of optical fibers 393 to 396.

  The plurality of lights that have passed through the plurality of optical fibers 393 to 396 are guided to the spectroscopic unit 130 through the fiber coupler 350, the optical fibers 397 and 398, the fiber coupler 340, and the optical fiber 392. Therefore, the plurality of lights that have passed through the plurality of optical fibers 393 to 396 are combined into one light in the process of being guided to the spectroscopic unit 130. In this case, it is not necessary to perform an operation in order to generate an average distribution of intensities for each wavelength for a plurality of lights that have passed through the plurality of optical fibers 393 to 396. Therefore, the averaging process of a plurality of lights can be easily performed efficiently at high speed.

  As shown in FIG. 20, a fiber coupler 340 is disposed on the processing apparatus 100 side, and a fiber coupler 350 is disposed on the measurement head 200 side. Further, the fiber couplers 340 and 350 are connected by optical fibers 397 and 398 having two cores 310a. According to this configuration, it is possible to improve the degree of design freedom for the arrangement of the fiber couplers 340 and 350 while suppressing the loss of the optical signal reflected from the measurement object S.

  In FIG. 20, the fiber coupler 350 is provided in the housing 210 of the measuring head 200, but the fiber coupler 350 may be provided in a connector portion between the housing 210 and the optical fibers 393 to 396. By arranging the fiber coupler 350 in a strong housing (connector portion) made of metal or the like, it is possible to prevent the measuring head 200 from being enlarged while fixing and protecting the fiber coupler 350. The fiber coupler 350 may be provided in the vicinity of the connector portion.

(3) Modified Example of Light Guide Unit The light guide unit 300 according to the second embodiment is provided between the light projecting unit 120 and the spectroscopic unit 130 in the processing apparatus 100 and the optical fibers 393 to 396 of the measurement head 200. The configuration for transmitting light includes a 2 × 2 type fiber coupler 340, a 2 × 4 type fiber coupler 350, and four optical fibers 391, 392, 397, and 398, but the present invention is not limited thereto.

  The optical fiber 391 may be connected to the port 351 of the fiber coupler 350, and the optical fiber 392 may be connected to the port 352 of the fiber coupler 350. Thereby, light can be transmitted between the light projecting unit 120 and the spectroscopic unit 130 and the optical fibers 393 to 396 of the measuring head 200. According to this configuration, the fiber coupler 340 and the optical fibers 397 and 398 in FIG. 20 are not necessary.

  Alternatively, the light guide unit 300 according to the second embodiment includes two 1 × 2 type fiber couplers instead of the 2 × 4 type fiber coupler 350, and these two fiber couplers are included in the measurement head 200. It may be provided. In this case, in one fiber coupler, the optical fiber 397 is connected to one port, and the optical fibers 393 and 394 are connected to two ports opposed to the one port. In the other fiber coupler, an optical fiber 398 is connected to one port, and optical fibers 395 and 396 are connected to two ports facing the one port. Thereby, light can be transmitted between the light projecting unit 120 and the spectroscopic unit 130 and the optical fibers 393 to 396 of the measuring head 200.

  Alternatively, in the light guide unit 300 according to the second embodiment, instead of the 2 × 2 type fiber coupler 340 and the 2 × 4 type fiber coupler 350, a 1 × 2 type fiber coupler and a 1 × 4 type fiber are used. A coupler may be provided. In this case, for example, a 1 × 2 type fiber coupler is provided in the processing apparatus 100, and a 1 × 4 type fiber coupler is provided in the measurement head 200. Further, the optical fibers 391 and 392 are connected to two ports of the 1 × 2 type fiber coupler, and one end of the optical fiber 397 is connected to one port opposed to the two ports. Further, the other end of the optical fiber 397 is connected to one port of the 1 × 4 type fiber coupler, and the optical fibers 393 to 396 are connected to four ports facing the one port. Thereby, light can be transmitted between the light projecting unit 120 and the spectroscopic unit 130 and the optical fibers 393 to 396 of the measuring head 200. According to this configuration, the optical fiber 398 in FIG. 20 is not necessary.

[3] Other Embodiments (1) In the first embodiment, the light guide unit 300 includes an optical fiber, and light is transmitted between the processing apparatus 100 and the measurement head 200 using the optical fiber. However, the present invention is not limited to this. The light guide unit 300 does not include an optical fiber, and light may be transmitted between the processing apparatus 100 and the measurement head 200 using optical elements such as a mirror and a half mirror.

  FIG. 23 is a schematic diagram illustrating a configuration of a confocal displacement meter according to another embodiment. The measurement head 200 in FIG. 23 does not have the optical fiber 314 in FIGS. 1 and 13. Further, the light guide unit 300 of this example is replaced with the optical fibers 311, 312, 319, the fiber coupler 320, and the fiber connector 330 of FIGS. 1 and 13, and a half mirror 371 and a plurality (two in this example) of spaces. Filters 372 and 373 are included. Pin holes 372a and 373a are formed in the spatial filters 372 and 373, respectively.

  The light emitted from the light projecting unit 120 passes through the pinhole 372a of the spatial filter 372 and then passes through the half mirror 371. The light that has passed through the half mirror 371 is applied to the measurement object S through the flat plate member 230 and the lens unit 220. In this state, the flat plate member 230 is rotated by a drive unit 240 (not shown). Thereby, light is irradiated to the annular area on the measuring object S. A part of the light reflected by the surface of the measuring object S passes through the flat plate member 230 and the lens unit 220 and is reflected by the half mirror 371. The light reflected by the half mirror 371 passes through the pinhole 373 a of the spatial filter 373 and is guided to the spectroscopic unit 130. The light receiving unit 140 receives the light dispersed by the spectroscopic unit 130 and outputs a light reception signal.

  The arithmetic processing unit 150 acquires the received light waveform W0 on which the averaging process has been performed based on the received light signal output from the light receiving unit 140. In this way, by performing the averaging process of the light reception waveform W0, a light component that causes a random measurement error due to irregular reflection is canceled out. By specifying the peak wavelength λ0 of the received light waveform W0, the measurement distance can be specified more accurately.

  Also in the second embodiment, as in the example of FIG. 23 described above, the light guide unit 300 does not include an optical fiber, and an optical element such as a mirror and a half mirror is used to connect the processing device 100 and the measurement head 200. Light may be transmitted between them. In this case, the confocal measurement device 500 is provided with, for example, four light sources 121, four spatial filters 372 and four spatial filters 373 respectively corresponding thereto.

  (2) In the first embodiment, an optical integration process is performed as an average process of received light waveforms corresponding to a plurality of portions of the measurement object S, but the present invention is not limited to this. As the received light waveform averaging process, an electrical integration process, an average process, or a weighted average process may be performed, or other processes may be performed.

  For example, the light receiving unit 140 may sequentially receive a plurality of light beams sequentially separated by the spectroscopic unit 130 and output a light reception signal for each of the plurality of light beams sequentially received. In this case, the control unit 152 calculates an average signal as a signal intensity for each wavelength by averaging or integrating the plurality of received light signals output from the light receiving unit 140 for each wavelength, and based on the calculated average signal The displacement of the measuring object S can be calculated.

  Alternatively, the light receiving unit 140 may receive a plurality of lights sequentially separated by the spectroscopic unit 130 within a plurality of exposure periods, and output a light reception signal for the light received within each exposure period. In this case, the control unit 152 calculates an average signal as a signal intensity for each wavelength by averaging or integrating the plurality of received light signals output from the light receiving unit 140 for each wavelength, and based on the calculated average signal The displacement of the measuring object S can be calculated. According to these configurations, in the calculation of the average signal, it is possible to perform a desired calculation in consideration of a plurality of light intensities. Thereby, the displacement of the measuring object S can be calculated more accurately.

  (3) In the specific example of FIG. 13 of the first embodiment, a hollow motor is used as the drive unit 240 to rotate the flat plate member 230, but the present invention is not limited to this. The drive part 240 should just be able to rotate the flat plate member 230, and may be comprised by motors other than a hollow motor, 1 or several rotor, a belt, etc. FIG.

  (4) In the first embodiment, coupling and branching of light are performed using the fiber coupler 320, but the present invention is not limited to this. The fiber coupler 320 may not be used, and light coupling and branching may be performed using a plurality of optical fibers 311, 312, and 319 in which a plurality of cores 310 a are fused together.

  (5) In the example of FIG. 13 of the first embodiment, the flat plate member 230 is disposed between the optical fiber 314 and the lens unit 220, but the present invention is not limited to this. The flat plate member 230 may be disposed at any position on the optical path.

  (6) In the second embodiment, the confocal displacement meter 500 is configured so that light is applied to four portions of the surface of the measurement object S, but the present invention is not limited to this. The confocal displacement meter 500 may be configured such that light is irradiated to two parts, three parts, or five or more parts of the surface of the measurement object S.

  Therefore, the number of optical fibers included in the fiber unit 301 is preferably 2 or more, and more preferably 4 or more. When the number of optical fibers of the fiber unit 301 is increased, the measurement accuracy can be further improved by the averaging process, while the outer diameter of the fiber unit 301 is increased. Therefore, the number of optical fibers may be determined according to the required measurement accuracy and the outer diameter of the fiber unit 301.

  (7) In the second embodiment, the fiber unit 301 is arranged so that the center thereof substantially coincides with the optical axis of the lens unit 220, but the present invention is not limited to this. The center of the fiber unit 301 may be arranged away from the optical axis of the lens unit 220.

  (8) In the second embodiment, a plurality of optical fibers 313 to 316 are arranged so as not to overlap the center of the fiber unit 301, but the present invention is not limited to this. For example, one optical fiber may be disposed so as to overlap the center of the fiber unit 301, and a plurality of other fibers may be disposed around the optical fiber.

  Further, the optical fibers 393 and 395 may be arranged so as to be displaced from the positions of the optical fibers 393 and 395 in FIG. 22 by half the distance L2 in the arrangement direction of the optical fibers 393 and 395. In this case, the optical fibers 393 to 396 may be arranged so that the optical fiber 393 contacts the optical fibers 394 and 396 and the optical fiber 396 contacts the optical fibers 393 and 395.

  (9) In the second embodiment, light is coupled and branched using a plurality of fiber couplers 340 and 350, but the present invention is not limited to this. The fiber couplers 340 and 350 may not be used, and light coupling and branching may be performed using a plurality of optical fibers 391 to 398 in which a plurality of cores 310a are fused together.

  (10) In the second embodiment, the light guide unit 300 is configured so that the four lights passing through the four optical fibers 393 to 396 are combined into one light in the process of being guided to the spectroscopic unit 130. However, the present invention is not limited to this.

  The light guide unit 300 may be configured such that four lights passing through the optical fibers 393 to 396 are individually guided to the spectroscopic unit 130. Further, the spectroscopic unit 130 and the light receiving unit 140 may be configured such that the four light beams separated by the spectroscopic unit 130 are individually received by the light receiving unit 140.

  In this case, four light receiving signals respectively corresponding to the four lights are output from the light receiving unit 140. Therefore, the control unit 152 calculates an average signal as the signal intensity for each wavelength by averaging or integrating the four received light signals output from the light receiving unit 140 for each wavelength, and measures based on the calculated average signal. The displacement of the object S can be calculated.

  A two-dimensional line sensor in which a plurality of pixels are two-dimensionally arranged can be used as the light-receiving unit 140 that individually and simultaneously receives the four lights separated by the spectroscopic unit 130. In this case, four light receiving areas are set in the two-dimensional line sensor as one-dimensional line sensors respectively corresponding to the four lights. Instead of using a two-dimensional line sensor as the light receiving unit 140, four one-dimensional line sensors may be used. In this example, four spectroscopic sections 130 may be provided so as to correspond to each of the four lights.

  (11) In the second embodiment, the light guide unit 300 is configured such that four lights passing through the four optical fibers 393 to 396 are combined into one light in the process of being guided to the spectroscopic unit 130. However, the present invention is not limited to this.

  In the process in which the four lights passing through the optical fibers 393 to 396 are guided to the spectroscopic unit 130, one combined light composed of two of the four lights and another synthesized light composed of the remaining two lights are generated. The light guide unit 300 may be configured such that the combined light is individually guided to the spectroscopic unit 130. Further, the spectroscopic unit 130 and the light receiving unit 140 may be configured such that the two combined lights separated by the spectroscopic unit 130 are individually received by the light receiving unit 140.

  In this case, the two light receiving signals respectively corresponding to the two combined lights are output from the light receiving unit 140. Therefore, the control unit 152 calculates an average signal as the signal intensity for each wavelength by averaging or integrating the two received light signals output from the light receiving unit 140 for each wavelength, and measures based on the calculated average signal. The displacement of the object S can be calculated.

  A two-dimensional line sensor in which a plurality of pixels are two-dimensionally arranged can be used as the light receiving unit 140 that receives two combined lights separated by the spectroscopic unit 130 individually and simultaneously. In this case, two light receiving areas are set in the two-dimensional line sensor as one-dimensional line sensors respectively corresponding to the two combined lights. Instead of using a two-dimensional line sensor as the light receiving unit 140, two one-dimensional line sensors may be used. In this example, two spectroscopic sections 130 may be provided so as to correspond to each of the two combined lights.

  (12) In the second embodiment, the light emitted from the light projecting unit 120 is simultaneously guided to the four optical fibers 393 to 396 and the four lights passing through the four optical fibers 393 to 396. Is guided to the spectroscopic unit 130 at the same time, but the present invention is not limited to this.

  The light guide unit 300 may be configured such that light emitted from the light projecting unit 120 is sequentially switched and input to the optical fibers 393 to 396. In this case, when the light emitted from the light projecting unit 120 is sequentially input to the optical fibers 393 to 396, the four lights that are reflected on the surface of the measurement object S and pass through the optical fibers 393 to 396, respectively, are sequentially generated. Light is received by the light receiving unit 140.

  Here, the light receiving unit 140 may perform exposure while the four light beams are applied to the light receiving unit 140. In this case, a light reception signal integrated during the exposure period is output from each pixel of the light receiving unit 140 after the exposure is completed. Thereby, the received light signal output from the light receiving unit 140 is subjected to intensity averaging processing. Therefore, the control unit 152 can calculate the displacement of the measurement object S based on the acquired light reception signal.

  On the other hand, the light receiving unit 140 may sequentially receive a plurality of lights sequentially separated by the spectroscopic unit 130 and output a light reception signal for each of the four lights sequentially received. In this case, the control unit 152 calculates an average signal as a signal intensity for each wavelength by averaging or integrating the four received light signals output from the light receiving unit 140 for each wavelength, and based on the calculated average signal The displacement of the measuring object S can be calculated.

  (13) In the first and second embodiments, a laser diode that emits light having a single wavelength is used as the light source 121 of the light projecting unit 120 in FIGS. 6 and 18. However, the present invention is not limited to this. Not. As the light source 121, an LED (light emitting diode) that emits light of a single wavelength may be used, or an LED that emits light of a wide wavelength band may be used. When an LED that emits light in a wide wavelength band such as white light is used as the light source 121, the phosphor 122 may be provided or the phosphor 122 may not be provided.

  (14) In the first and second embodiments, the light projecting unit 120 emits light having a wavelength of 500 nm to 700 nm, but the present invention is not limited to this. The light projecting unit 120 may emit light in other wavelength bands. For example, the light projecting unit 120 may emit light in the infrared region or emit light in the ultraviolet region.

  (15) In the first and second embodiments, the processing apparatus 100 and the measurement head 200 are configured as separate bodies, but the present invention is not limited to this. The processing apparatus 100 and the measurement head 200 may be integrally configured.

  (16) In the above embodiment, the control unit 152 of the arithmetic processing unit 150 corrects the light reception signal acquired from the light receiving unit 140, measures the displacement of the measurement object S, and displays the measurement result as the sub display unit. 400. Further, the control unit 152 gives a light reception signal acquired from the light receiving unit 140 to the PC 600. On the other hand, the CPU 601 of the PC 600 executes a displacement measurement process for the measurement object S based on the displacement measurement program. The present invention is not limited to this.

  For example, the PC 600 may not be provided. In this case, the main display unit 700 and the operation unit 800 may be connected to the arithmetic processing unit 150 of the processing device 100. Further, the displacement measurement program may be stored in the storage unit 151 of the arithmetic processing unit 150. Thereby, the control unit 152 may execute various processes related to the displacement measurement process and the displacement measurement result based on the displacement measurement program.

[4] Correspondence relationship between each constituent element of claim and each part of the embodiment Hereinafter, an example of correspondence between each constituent element of the claim and each part of the embodiment will be described. It is not limited.

  In the above embodiment, the measurement object S is an example of the measurement object, the confocal displacement meter 500 is an example of the confocal displacement meter, the light projecting unit 120 is an example of the light projecting unit, and the lens unit 220. Is an example of an optical member, the tip portion of the optical fiber 314 or the pinhole 373a of the spatial filter 373 is an example of one pinhole, and the tip portions of the optical fibers 393 to 396 are examples of a plurality of pinholes, The optical fibers 314, 393 to 396 or the spatial filter 373 are examples of pinhole members.

  Further, the spectroscopic unit 130, the light receiving unit 140, the arithmetic processing unit 150, the light guide unit 300, and the CPU 601 are examples of the displacement measuring unit, the unnecessary component removal correction is an example of the first correction processing, and the light receiving waveform shift correction is performed. It is an example of the second correction process, the light reception waveform scale correction is an example of the third correction process, the peak Px is an example of the first peak, the peak Py is an example of the second peak, and the peak Pz is an example of the third peak.

  The optical fibers 319, 397, and 398 are examples of optical fibers, the light source 121 is an example of a light source, the phosphor 122 is an example of a phosphor, the spectroscopic unit 130 is an example of a spectroscopic unit, and the light receiving unit. 140 is an example of the light receiving unit, the arithmetic processing unit 150 and the CPU 601 are examples of the calculating unit, the fiber couplers 340 and 350 are examples of the combining unit, the light irradiation unit 1 is an example of the light irradiation unit, and the irradiation Region IR is an example of a region.

  The processing apparatus 100 is an example of a processing apparatus, the measurement head 200 is an example of a head unit, the casing 110 is an example of a first casing, and the casing 210 is an example of a second casing. The lens 124 is an example of a condensing member, the refractive lens 221 is an example of a refractive lens, and the diffractive lens 222 is an example of a diffractive lens.

  As each constituent element in the claims, various other elements having configurations or functions described in the claims can be used.

  The present invention can be effectively used for various confocal displacement meters.

DESCRIPTION OF SYMBOLS 1 Light irradiation part 100 Processing apparatus 110,210 Case 120 Light projection part 121 Light source 122 Phosphor 123 Ferrule 124,128,132,133 Lens 125 Holder 126 Filter element 127 Element holder 127A Light source fixing part 127B Ferrule fixing part 127C Lens Fixed unit 129 Reflecting member 130 Spectroscopic unit 131 Diffraction grating 140 Light receiving unit 150 Arithmetic processing unit 151 Storage unit 152 Control unit 160 Power supply unit 200 Measuring head 220 Lens unit 221 Refractive lens 222 Diffraction lens 223 Objective lens 224 Doublet lens 230 Flat plate member 231 Incident surface 232 Outgoing surface 240 Drive unit 241 Fixing unit 242 Rotating shaft 300 Light guide unit 301 Fiber unit 302 Holding member 310a Core 310b Clad 311 312 314, 319, 391, 392, 393, 394, 395, 396, 397, 398 Optical fiber 320, 340, 350 Fiber coupler 321, 322, 323, 331, 332, 341, 342, 343, 344, 351, 352 353, 354, 355, 356 Ports 324, 333, 345, 357 Main body 330 Fiber connector 371 Half mirror 372, 373 Spatial filter 372a, 373a Pinhole 400 Sub display 491 Switch button 500 Confocal displacement meter 600 PC
601 CPU
602 Memory 700 Main display section 800 Operation section BL Base waveform IR irradiation area L1 Diameter L2 Distance MR Measurement range OD Outer diameter P0, Px, Py, Pz Peak P1, P2 In-focus position PD Multi-segment RP Reference position S Measurement object W0 , W1, W2, W3, W4 Light receiving waveform λ0 to λ4, λx, λy Peak wavelength

Claims (16)

A confocal displacement meter that measures the displacement of a measurement object using a confocal optical system,
A light projecting unit that emits light having a plurality of wavelengths;
An optical member that generates chromatic aberration along the optical axis direction in the light emitted by the light projecting unit, converges the light having chromatic aberration, and irradiates the measurement object;
A pinhole member having one or a plurality of pinholes that allows light of a wavelength reflected while being focused on the surface of the measurement object among light irradiated to the measurement object by the optical member;
The measurement object based on the signal intensity for each wavelength of the average signal corresponding to the average of the intensity for each wavelength of the plurality of lights reflected by the plurality of portions of the measurement object and passed through the one or more pinholes A displacement measuring unit for calculating the displacement of the object,
Before calculating the displacement of the measurement object, the displacement measurement unit is at least one of unnecessary components corresponding to unnecessary light excluding light reflected from the average signal while being focused on the surface of the measurement object. A confocal displacement meter that performs a first correction process so that a portion is removed. A processing device;
The head,
An optical fiber connecting the processing device and the head unit;
The processing apparatus further includes a first housing that includes a part of the displacement measuring unit and the light projecting unit and that houses a part of the displacement measuring unit and the light projecting unit,
The head portion includes the optical member and the pinhole member, and further includes a second housing that accommodates the optical member and the pinhole member,
The optical fiber guides the light emitted by the light projecting unit to the optical member,
The confocal displacement meter according to claim 1, wherein at least a part of the optical fiber is a portion of the displacement measurement unit that is not accommodated in the first housing. One end of the optical fiber is provided in the first housing,
The other end of the optical fiber is provided in the second housing,
The light projecting unit is
A light source comprising a laser diode;
A condensing member that condenses the light generated by the light source;
And a phosphor that is provided at one end of the optical fiber and absorbs part of the light collected by the light collecting member and emits light having a plurality of wavelengths to the optical member through the optical fiber. Item 3. The confocal displacement meter according to Item 2. The unnecessary component includes an unnecessary peak whose position on the wavelength axis of the average signal does not depend on the displacement of the measurement object,
The displacement measuring unit corrects the shift on the wavelength axis of the average signal depending on the temperature based on the position of the unnecessary peak on the wavelength axis of the average signal before the first correction processing. The confocal displacement meter according to claim 1, wherein the second correction processing is performed. The confocal point according to claim 4, wherein the unnecessary peak includes a first peak corresponding to the first unnecessary light that is emitted from the light projecting unit and reflected by the optical member and guided to the displacement measuring unit. Displacement meter. The light projecting unit is
A light source;
A phosphor that absorbs part of the light generated by the light source and emits light having a plurality of wavelengths to the optical member;
6. The confocal displacement according to claim 4, wherein the unnecessary peak includes a second peak corresponding to second unnecessary light that is generated by the light source and is emitted to the optical member while passing through the phosphor. Total. The displacement measuring unit includes a spectroscopic unit that diffracts light that has passed through the one or more pinholes,
The confocal displacement meter according to any one of claims 4 to 6, wherein the unnecessary peak includes a third peak corresponding to third unnecessary light that is zero-order diffracted by the spectroscopic unit. The unnecessary component includes at least two unnecessary peaks whose position on the wavelength axis of the average signal does not depend on the displacement of the measurement object,
Before the first correction process, the displacement measuring unit is based on the position of the at least two unnecessary peaks on the wavelength axis of the average signal, on the wavelength axis of the average signal depending on temperature. The confocal displacement meter according to claim 1, wherein a third correction process for correcting the scale is performed. The light projecting unit is
A light source;
A phosphor that absorbs part of the light generated by the light source and emits light having a plurality of wavelengths to the optical member;
The displacement measuring unit includes a spectroscopic unit that reflects and splits light that has passed through the one or more pinholes,
The at least two unnecessary peaks are generated by the light source, the first peak corresponding to the first unnecessary light that is emitted from the light projecting unit and reflected by the optical member and guided to the displacement measuring unit. A second peak corresponding to the second unnecessary light emitted to the optical member while passing through the phosphor, and a third peak corresponding to the third unnecessary light that is zero-order diffracted by the spectroscopic unit. 9. The confocal displacement meter according to claim 8, comprising at least two peaks. The pinhole member includes a plurality of pinholes,
The displacement measuring unit is
Based on the signal intensity for each wavelength of the average signal corresponding to the average of the intensity for each wavelength for the plurality of lights reflected by the plurality of portions of the measurement object and passed through the plurality of pinholes, The confocal displacement meter as described in any one of Claims 1-6 or 8 which calculates a displacement. The displacement measuring unit is
A combining unit that generates a single combined light by combining a plurality of lights acquired by the plurality of light acquiring units;
A spectroscopic unit for splitting the synthesized light generated by the synthesizing unit;
A light receiving unit that receives light split by the spectroscopic unit and outputs an electrical light reception signal indicating an intensity for each wavelength of the combined light generated by the combining unit as an average signal;
The confocal according to claim 10, further comprising: a calculation unit that performs the first correction process on the average signal output from the light receiving unit and calculates a displacement of the measurement object based on the corrected average signal. Displacement meter. A light irradiating unit that sequentially irradiates the plurality of portions of the measurement object with the light emitted by the light projecting unit;
The optical member generates chromatic aberration in light irradiated on the measurement object by the light irradiation unit, and converges light having chromatic aberration,
The pinhole member includes one pinhole,
The one pinhole sequentially passes light having wavelengths reflected while being focused on the plurality of portions of the measurement object,
The displacement measuring unit is
The displacement of the measurement object is calculated based on the signal intensity for each wavelength of the average signal corresponding to the average of the intensity for each wavelength for the plurality of lights sequentially passing through the one pinhole. The confocal displacement meter according to any one of 8 and 10. The displacement measuring unit is
A spectroscopic unit that sequentially splits a plurality of lights that have sequentially passed through the one pinhole;
A light receiving unit that receives a plurality of lights sequentially separated by the spectroscopic unit within a single exposure period, and outputs an electrical light reception signal indicating an intensity for each wavelength of the received light as an average signal;
The confocal displacement according to claim 12, further comprising: a calculation unit that performs the first correction process on the average signal output from the light receiving unit and calculates the displacement of the measurement object based on the corrected average signal. Total. The displacement measuring unit is
A spectroscopic unit that sequentially splits a plurality of lights that have sequentially passed through the one pinhole;
A light receiving unit that sequentially receives a plurality of light beams that are sequentially split by the beam splitting unit, and that outputs an electrical light reception signal indicating the intensity for each wavelength for each of the plurality of light beams that are sequentially received;
An average signal is calculated as a signal intensity for each wavelength by averaging or integrating a plurality of light receiving signals output from the light receiving unit for each wavelength, and a plurality of light receiving signals output from the light receiving unit or a calculated average The confocal displacement meter according to claim 12, further comprising: a calculation unit that performs the first correction process on the signal and calculates a displacement of the measurement object based on the corrected average signal. The plurality of portions are located on an annular region of the surface of the measurement object,
The light irradiating unit sets the optical axis of the light emitted by the light projecting unit so that the light is irradiated to a plurality of portions on an annular region of the surface of the measuring object. The confocal displacement meter according to any one of claims 12 to 14, which is shifted along the axis. The optical member is
A refractive lens having a convex shape;
A diffractive lens having a concave shape,
The confocal displacement meter according to any one of claims 1 to 15, wherein the refractive lens and the diffractive lens are arranged so that light emitted from the light projecting unit passes therethrough.

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