JP2020020815A - Confocal displacement meter - Google Patents

Abstract

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 in a wide wavelength band.

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

  The first optical path is configured such that light of different wavelengths is focused at different distances near the surface position of the measurement object in the optical axis direction. Light that has passed through the first optical path is reflected on the surface of the measurement target. Of the reflected light, only light focused at the position of the opening disposed on 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 lights of different wavelengths are focused at substantially the same distance near the surface position of the measurement target. Light that has passed through the second optical path is reflected on the surface of the measurement target. Of the reflected light, only 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 spectrum profile (second output spectrum 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 the first output spectral profile for potential measurement errors associated with distance-independent profile components.

JP 2013-130581 A

  In the CPS system described in Patent Literature 1, reliability is improved by performing the above-described correction on the first output spectrum profile. Specifically, measurement errors due to the material component of the measurement target, the spectral profile component of the light source associated with the light source, or the component associated with the wavelength detector are reduced as the distance-independent profile components. However, in the confocal displacement meter, a measurement error having a degree larger than the surface roughness 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 capable of reducing a measurement error.

  (1) A confocal displacement meter according to the present invention is a confocal displacement meter that measures a displacement of an object to be measured using a confocal optical system, and includes 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, and the optical member irradiates the measurement object. Among the light, a pinhole member having one or a plurality of pinholes for transmitting light having a wavelength reflected while being focused on the surface of the measurement object, and light sequentially from the optical member to a plurality of portions of the measurement object. By being simultaneously reflected from a plurality of lights or optical members sequentially passing through one pinhole after being sequentially reflected on a plurality of portions of the measurement object by being irradiated, the plurality of portions of the measurement object are simultaneously irradiated with light. Multiple objects to be measured The displacement for calculating 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 a plurality of lights that have been simultaneously reflected by the portions and then passed through a plurality of pinholes at the same time A measuring unit, and a displacement measuring unit, before calculating the displacement of the measurement object, calculates unnecessary components corresponding to unnecessary light except for light reflected while being focused on the surface of the measurement object from the average signal. A first correction process is performed so that at least a part is removed, and at least a part of 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. Includes a first peak corresponding to the first unnecessary light emitted from the light projecting unit, reflected by the optical member, and guided to the displacement measuring unit.

  In the confocal displacement meter, light having a plurality of wavelengths is emitted by the light projecting unit. In the light emitted by the light projecting unit, chromatic aberration occurs along the optical axis direction by the optical member. Further, light having chromatic aberration is converged by the optical member and is irradiated on the measurement target.

  Light is sequentially emitted from the optical member to a plurality of portions of the measurement target, so that the light applied to the plurality of portions of the measurement target is reflected while being focused on a plurality of portions of the surface of the measurement target. The plurality of light beams sequentially pass through one pinhole of the pinhole member. Alternatively, by irradiating the plurality of portions of the measurement object from the optical member at the same time, of the light irradiated on the plurality of portions of the measurement object, the plurality of portions on the surface of the measurement object are focused. The plurality of lights reflected while passing through the plurality of pinholes of the pinhole member at the same time. 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 of the plurality of lights passing 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 the above configuration, intensities of the plurality of lights passing through one or more pinholes for each wavelength in the average signal are averaged. This cancels out light components that cause random measurement errors due to diffuse reflection. Further, the first correction processing is performed before the displacement of the measurement target is calculated, thereby eliminating unnecessary light corresponding to unnecessary light excluding light reflected while being focused on the surface of the measurement target from the average signal. At least some of the components are removed. As a result, it is possible to reduce errors in the displacement of the measurement object measured by the confocal displacement meter.

  In the above configuration, at least a part of 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 target. Further, the unnecessary peak includes a first peak corresponding to the first unnecessary light emitted from the light projecting unit and reflected by the optical member and guided to the displacement measuring unit. In this case, components emitted from the light projecting unit and reflected by the optical member and guided to the displacement measuring unit are removed, so that errors in displacement of the measuring object can be further reduced.

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

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

  (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 a light source including a laser diode and a light source. A condensing member for condensing light, and a fluorescent light provided at one end of the optical fiber for absorbing a part of the light condensed by the condensing member and emitting light having a plurality of wavelengths to the optical member through the optical fiber 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. Accordingly, the amount of light having a plurality of wavelengths generated from the phosphor increases.

  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 the light is optically transmitted from the other end of the optical fiber. The object to be measured is irradiated through the member. Therefore, even when the size of the irradiation region formed on the measurement target is reduced, the amount of light passing through one or more pinholes is prevented from being significantly reduced. As a result, the size of the irradiation area can be reduced.

  (4) The displacement measuring unit corrects the shift of the average signal on the wavelength axis 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. 2 may be performed.

  Since the first unnecessary light does not reach the measurement target, the position of the first peak on the wavelength axis of the average signal does not depend on the displacement of the measurement target. Therefore, the position of the first 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 first 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 compensating the shift of the average signal on the wavelength axis depending on the temperature based on the position of the first peak on the wavelength axis of the average signal, compensating the fluctuation of the measurement result due to the temperature change. Can be.

  (5) 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 unnecessary peaks are generated by the light source. And a second peak corresponding to the second unnecessary light emitted to the optical member while passing through the phosphor.

  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, it is possible to compensate for the variation of the measurement result due to the temperature change by correcting the shift of the average signal on the wavelength axis depending on the temperature based on the position of the second peak on the wavelength axis of the average signal. it can.

  (6) The displacement measurement unit includes a spectroscopic unit that splits the light that has passed through one or more pinholes by diffracting the light, and the unnecessary peak corresponds to the third unnecessary light diffracted by the zeroth order in the spectroscopic unit. It may include a third peak.

  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, so that 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 target. Therefore, it is possible to compensate for the variation of the measurement result due to the temperature change by correcting the shift of the average signal on the wavelength axis depending on the temperature based on the position of the third peak on the wavelength axis of the average signal. it can.

  (7) The unnecessary component includes at least two unnecessary peaks, and the displacement measurement unit determines the temperature before the first correction processing based on the positions of the at least two unnecessary peaks on the wavelength axis of the average signal. A third correction process for correcting the scale of the dependent average signal 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. Thus, the spacing between two unwanted peaks on the wavelength axis of the average signal corresponds to a shift in scale on the wavelength axis of the average signal due to a change in temperature. Therefore, by compensating the scale of the average signal on the wavelength axis which is dependent on the temperature based on the positions of the two unnecessary peaks on the wavelength axis of the average signal, the fluctuation of the measurement result due to the temperature change is compensated. Can be.

  (8) 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. At least two unnecessary peaks are a first peak, a second peak generated by the light source and emitted to the optical member while passing through the phosphor. At least two peaks may be included among the second peak corresponding to the unnecessary light and the third peak corresponding to the third unnecessary light diffracted by the 0th order in the spectroscopic unit.

  In this case, since the first unnecessary light does not reach the measurement target, the position of the first peak on the wavelength axis of the average signal does not depend on the displacement of the measurement target. 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 target. Since the third unnecessary light, which is the zero-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. Therefore, by correcting the scale on the wavelength axis of the average signal that depends on temperature based on the position of at least two peaks among the first to third peaks on the wavelength axis of the average signal, the temperature change Variations in measurement results can be compensated.

  (9) The pinhole member includes a plurality of pinholes, and the displacement measurement unit measures the displacement of the measurement target 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. It may be calculated.

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

  (10) The displacement measurement unit combines a plurality of lights to generate one combined light, a dispersing unit that disperses the combined light generated by the combining unit, and a light that is disperse by the dispersing unit. A light receiving unit that receives and outputs an electric light receiving signal indicating an intensity for each wavelength of the combined light generated by the combining unit as an average signal, and performs a first correction process on the average signal output from the light receiving unit. A calculating unit that calculates the displacement of the measurement target based on the corrected average signal.

  In this case, a plurality of lights 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 electric light receiving signal indicating the intensity for each wavelength output from the light receiving unit is an average signal obtained by integrating the intensities for a plurality of lights for each wavelength. 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 efficiently calculated at high speed.

  (11) The confocal displacement meter further includes a light irradiating unit that sequentially irradiates the light emitted by the light projecting unit to a plurality of portions of the measurement object, and the optical member irradiates the measurement object with the light irradiation unit. The chromatic aberration is generated while the chromatic aberration is converged, and the pinhole member includes one pinhole, and the one pinhole is reflected while being focused on a plurality of portions of the measurement target. The light of the wavelength is sequentially transmitted, and the displacement measurement unit is configured to determine the measurement target 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 sequentially passing through one pinhole. The displacement may be calculated.

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

  (12) The displacement measurement unit receives a plurality of lights sequentially separated by the splitting unit within a single exposure period, and receives a plurality of lights sequentially split by the splitting unit. A light receiving unit that outputs an electric light receiving signal indicating the intensity of light for each wavelength as an average signal, and performs a first correction process on the average signal output from the light receiving unit, and performs measurement based on the corrected average signal. And a calculating unit for calculating the displacement of the object.

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

  (13) The displacement measurement unit sequentially disperses a plurality of lights sequentially passing through one pinhole, and sequentially receives the plurality of lights sequentially dissipated by the dispersing unit, and receives the plurality of lights sequentially received. Calculates the average signal as the signal intensity for each wavelength by averaging or integrating for each wavelength the light receiving unit that outputs an electrical light receiving signal indicating the intensity for each wavelength and the multiple light receiving signals output from the light receiving unit 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 target 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. The average signal is calculated by averaging or integrating a plurality of light receiving signals output from the light receiving unit for each wavelength by the calculating unit. According to this configuration, in the calculation of the average signal, a desired average or integration can be performed in consideration of the intensities of a plurality of lights. Thereby, the displacement of the measurement object can be calculated more accurately.

  (14) The plurality of portions are located on an annular region on the surface of the measurement target, and the light irradiating unit is configured to irradiate the plurality of portions on the annular region on the surface of the measurement target with light. Alternatively, the light emitted by the light projecting unit may be shifted along the surface of the measurement target.

  According to this configuration, the burden on the physically operating portion of the light irradiation section is smaller than when a plurality of portions on the linear region on the surface of the measurement target are irradiated with light. Thereby, the life of the light irradiation part can be prolonged.

  (15) The optical member includes 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 such that light emitted from the light projecting portion passes therethrough.

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

  According to the present invention, a measurement error of a measurement target can be reduced.

FIG. 1 is a schematic diagram illustrating a configuration of a confocal displacement meter according to a first embodiment. It is an example of a display of a value of a measurement result in a main display part. 6 is a display example of a waveform of a light reception signal on a main display unit. FIG. 5 is a diagram for explaining the operation principle of a confocal displacement meter using a measurement head. FIG. 5 is a diagram illustrating a relationship between a wavelength of light received by a light receiving unit and an intensity of a light receiving 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 by a part different from a measurement object. FIG. 6 is a diagram illustrating a light reception waveform including an unnecessary component. It is a figure showing the base waveform of a light-receiving waveform. FIG. 7 is a diagram showing a received light waveform from which a base waveform has been removed. FIG. 4 is a diagram illustrating a path of light guided to a light receiving unit. FIG. 12 is a diagram illustrating a light reception waveform of light guided to the light receiving unit in FIG. 11. FIG. 2 is a schematic diagram illustrating a more specific configuration of the confocal displacement meter of FIG. 1. FIG. 14 is a diagram for explaining the operation principle of a confocal displacement meter using the measurement head of FIG. 13. FIG. 15 is a diagram illustrating an optical path of light when the driving unit in FIG. 14 rotates. FIG. 15 is a diagram illustrating an area of a measurement target irradiated with light by the measurement head of FIG. 14. It is a figure showing the 1st-the 4th modification of a lens unit. It is a figure which shows the modification of a light projection part. It is a figure showing the modification of a spectrum part. FIG. 9 is a schematic diagram illustrating a configuration of a confocal displacement meter according to a second embodiment. FIG. 21 is a diagram for explaining the operation principle of a confocal displacement meter using the measurement head of FIG. 20. FIG. 22 is a sectional view showing an arrangement of four optical fibers in FIG. 21. FIG. 9 is a schematic diagram illustrating a configuration of a confocal displacement meter according to another 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 a 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 device 100 and the measurement head 200.

  The processing device 100 includes a housing 110, a light projecting unit 120, a spectral 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 emitting unit 120, the light splitting 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 in a wide wavelength band (for example, 500 nm to 700 nm), that is, light having a plurality of wavelengths. The detailed configuration of the light projecting unit 120 will be described later. The light emitted by the light projecting unit 120 is input to an optical fiber 311 of the light guide unit 300 described later.

  The light splitting unit 130 includes a diffraction grating 131 and a plurality of (two in this example) lenses 132 and 133. As described later, a part of the light emitted by the light projecting unit 120 and reflected on the surface of the measurement target S is output from the optical fiber 312 of the light guide unit 300. The light output from the optical fiber 312 is substantially collimated by passing through the lens 132, and is incident on the diffraction grating 131. In the present embodiment, the diffraction grating 131 is a reflection type 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 different for each wavelength by passing through the lens 133.

  The light receiving unit 140 includes an image sensor (one-dimensional line sensor) in which a plurality of pixels are arranged one-dimensionally. The imaging device may be a multi-segment PD (photodiode), a CCD (charge coupled device) camera or a CMOS (complementary metal oxide semiconductor) image sensor, or may be another device. The light receiving unit 140 is arranged such that a plurality of pixels of the image sensor receive light at a plurality of focusing positions different for each wavelength formed by the lens 133 of the spectral unit 130. Each pixel of the light receiving unit 140 outputs an analog electric signal (hereinafter, referred to as a light receiving signal) corresponding to the amount of received light. The light receiving 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 device 100 and a calculation program for calculating displacement, and also stores 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 receiving signal output by the light receiving unit 140, measures the displacement of the measurement target S based on the calculation program and the data stored in the storage unit 151, and transmits the measurement result to the sub display unit 400. indicate.

  Here, the PC 600 is connected to the arithmetic processing unit 150. 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 device 100 further provides the light receiving signal acquired from the light receiving unit 140 to the CPU 601 of the PC 600. The CPU 601 acquires the light receiving signal provided from the control unit 152, measures the displacement of the measurement target S based on the displacement measurement program and the data stored in the memory 602, and performs various processes related to the measurement result. . For example, the CPU 601 displays the value of the measurement result on the display unit 700. Further, the CPU 601 displays the waveform of the light receiving signal provided from the control unit 152 on the display unit 700. Further, the CPU 601 displays statistics on a plurality of measurement results obtained at a plurality of time points before the current time point on the display unit 700.

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

  A fiber connector 330 of the light guide 300 described below 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 diffraction lens 222, and an objective lens 223. The light guided to the lens unit 220 passes through the refraction lens 221 and the diffraction lens 222 in order. Thereby, chromatic aberration occurs in the light along the optical axis direction. The light in which the chromatic aberration has occurred is guided to the outside of the housing 210 through the objective lens 223, and is irradiated on the measurement target S. The objective lens 223 is arranged so that light having chromatic aberration can be focused at a position near the surface of the measurement target S.

  The light irradiation unit 1 includes, for example, an electric driving mechanism, and shifts light emitted from the measurement head 200 toward the measurement target S in a direction orthogonal to the optical axis of the lens unit 220. Note that the light irradiation unit 1 only needs to be able to shift the light irradiated to the measurement target S, and does not need to be provided inside the housing 210. In this case, the light irradiation unit 1 may be configured to be able to move the housing 210 relatively to the measurement target S, for example, or to move the measurement target S relative to the housing 210. May be configured to be able to be moved.

  Power is supplied from the power supply unit 160 of the processing apparatus 100 to the light irradiation unit 1 of this example via a power cable (not shown). Therefore, it is not necessary to house a device for supplying power to the light irradiation unit 1 in the housing 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, and 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 device 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 housing 110 of the processing device 100. Further, the fiber connector 330 may be provided in a portion other than the housing 210 of the measurement 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. The 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 fibers 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. The port 323 of the fiber coupler 320 and the port 331 of the fiber connector 330 are connected by an optical fiber 319.

  According to this configuration, the light emitted by the light projecting unit 120 of the processing device 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 is 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 is applied to the measurement target S through the optical fiber 314 and the lens unit 220.

  Part of the light reflected on the surface of the measurement target 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. The 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 light splitting unit 130 through the optical fiber 312. Thereby, the displacement measurement processing 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 section 700 and operation section 800 are connected to PC 600. As described above, for example, the value of the measurement result of the displacement or the waveform of the light receiving signal is displayed on the main display unit 700. By operating the operation unit 800, the user can operate various buttons displayed on the main display unit 700, for example, and can input desired information regarding displacement measurement.

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

  The user can switch the display state of the main display unit 700 to the display state of the received light waveform in FIG. 3 by operating the switching button 491 in FIG. 2 using the operation unit 800 in FIG. The user operates the switching button 491 in FIG. 3 using the operation unit 800 in FIG. 1 to switch the display state of the main display unit 700 to the display state of the numerical measurement result values in FIG. Can be.

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

  In the PC 600, a reference range for determining whether the measurement target S is good or bad with respect to the measurement distance may be set. In this case, when the measurement distance is within the reference range, a determination result (for example, “OK”) indicating that the measurement target S is a non-defective product is displayed on the main display unit 700. On the other hand, when the measurement distance is out of the reference range, a determination result (for example, “NG”) indicating that the measurement target S is defective 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 cladding 310b. 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 in FIG. 1 have the same configuration as the optical fiber 314. The diameter of the core 310a is preferably 200 μm or less, more preferably 50 μm or less.

  The light output from the optical fiber 314 passes through the refraction lens 221 and the diffraction lens 222. This causes chromatic aberration in the light. The light in which chromatic aberration has occurred passes through the objective lens 223 and is focused at different positions for each wavelength. For example, light with a short wavelength focuses on a position near the objective lens 223, and light with a long wavelength focuses on a position far from the objective lens 223. The range between the focus position P1 closest to the objective lens 223 and the 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 light increases. Thereby, the measurement range MR can be enlarged.

  When the surface of the measurement target S exists in the measurement range MR, the light that has passed through the objective lens 223 irradiates the surface of the measurement target S, and is then reflected by the surface in a wide range. Here, in the present embodiment, the distal end portion of the optical fiber 314 functions as a spatial filter having minute pinholes. Therefore, most of the light reflected on the surface of the measurement target 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 target S is reflected by the surface, passes through the lens unit 220, and is input to the tip 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 a position on the surface of the measurement target S. In this example, the reference position RP is the position of the end of the housing 210 closest to the measurement target S.

  The light input to the optical fiber 314 is guided to the processing device 100 in FIG. 1, is separated by the diffraction grating 131, and is focused by the lens 133 at a different position for each wavelength. The plurality of pixels of the light receiving unit 140 are respectively arranged at in-focus positions of a plurality of light beams different for each wavelength. Therefore, each pixel of the light receiving unit 140 receives light having a wavelength corresponding to the pixel, and outputs a light receiving 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 receiving 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 target S may be input to the optical fiber 314 due to irregular reflection of light on the surface of the measurement target S. In this case, a measurement error having a degree greater than the surface roughness of the measurement target S occurs in the measurement distance specified by the processing device 100.

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

  FIG. 5 is a diagram illustrating the relationship between the wavelength of light received by the light receiving unit 140 and the intensity of a 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 in FIG. 5 and FIGS. 8 to 10 and FIG.

  In this example, the light irradiation unit 1 shifts the light emitted from the measurement head 200 toward the measurement target S such that the four different portions of the surface of the measurement target S are sequentially irradiated with the light. . In FIG. 5, waveforms of light receiving signals (hereinafter, referred to as light receiving waveforms) W1 to W4 corresponding to light input to the optical fiber 314 when light is irradiated on four portions of the surface of the measurement target S. Are indicated by a dotted line, a dashed line, a two-dot chain line, and a broken line, respectively. The peak wavelengths of the light receiving waveforms W1 to W4 (hereinafter, referred to as peak wavelengths) are λ1 to λ4, respectively. The peak wavelengths λ1 to λ4 of the plurality of light reception waveforms W1 to W4 are different from each other due to irregular reflection on the surface of the measurement target S.

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

  As described above, by optically averaging the received light waveform W0, light components that generate random measurement errors due to irregular reflection are canceled. 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 to be specified when diffused reflection of light does not occur. Therefore, by specifying the peak wavelength λ0 of the received light waveform W0, the measurement distance can be specified more accurately.

(3) Light Projecting Section FIGS. 6A and 6B are a plan view and a cross-sectional view illustrating the configuration of the light projecting section 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 fixed to the light source fixing portion 127A, the ferrule fixing portion 127B, and the lens fixing portion 127C of the element holder 127, respectively.

  The light source 121 is a laser diode that emits light of a single wavelength. In the present embodiment, the light source 121 emits light in a blue region or an ultraviolet region having a wavelength of 450 nm or less. The phosphor 122 absorbs excitation light in a blue region or an 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. Note that the phosphor 122 may emit fluorescent light in a yellow region, may emit fluorescent light in a green region, or may emit fluorescent light in a red region. Further, 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 300 of FIG. The lens 124 is disposed between the light source 121 and the ferrule 123. One end surface of an annular holder 125 is attached to an 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 reflection filter that reflects light in a yellow region, a green region, or a red region and transmits light in a blue region or an ultraviolet region.

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

  The light generated in the light projecting unit 120 is input to the optical fiber 311 by passing through the ferrule 123. The fluorescent light 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. Thus, the fluorescent light can be efficiently input to 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 surface of the ferrule 123. In this case, the light projecting unit 120 does not include the holder 125. Further, the light projecting unit 120 includes the filter element 126, but the present invention is not limited to this. When sufficient fluorescent light 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 formulas for the pixel position of the light receiving unit 140, the peak wavelength λ0 of the output light receiving waveform W0, and the measurement distance are described above. It is stored in advance together with the calculation program. The control unit 152 of the arithmetic processing unit 150 specifies the position of the pixel that outputs the light-receiving signal, and based on the specified position of the pixel and the conversion formula stored in the storage unit 151, determines the peak wavelength λ0 and the peak wavelength λ0 of the light-receiving waveform W0. 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 measurement target S can be measured. Further, 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 more accurately calculate the measurement distance.

(A) Unnecessary Component Removal Correction Light that is different from light reflected while being focused on the surface of the measurement target S may be received by the light receiving unit 140. In the following description, of the light received by the light receiving unit 140, light excluding light reflected while being focused on the surface of the measurement target 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 target S. In FIG. 7, illustration of the light irradiation unit 1 in FIG. 1 is omitted. In the example of FIG. 7, light (light indicated by an arrow) directly reflected by the refraction lens 221 of the lens unit 220 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 an unnecessary component. The light receiving waveform W0 in FIG. 8 includes three peaks P0, Px, and Py. The peak P0 is generated by light reflected while being focused on the surface of the measurement target 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 by 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 the light of 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 target S while passing through the phosphor 122 (FIG. 6). It is generated by unnecessary light reflected without being in focus. 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 for removing a portion (hereinafter, referred to as a base waveform BL) caused by the peak Px from the received light waveform W0 as an unnecessary component is performed.

  FIG. 9 is a diagram showing a base waveform BL of the received light waveform W0. In the present embodiment, control unit 152 obtains base waveform BL in FIG. 9 by applying low-pass filter processing for identifying peak Px and peak P0 to 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 the storage unit 151 of FIG. 1 in advance. In this case, the control unit 152 corrects the received light waveform W0 based on the acquired base waveform BL in FIG. 9 so as to remove the base waveform BL from the received light waveform W0 in FIG.

  FIG. 10 is a diagram showing the received light waveform W0 from which the base waveform BL has been removed. In the example of FIG. 10, the peak wavelength λ0 is slightly shifted to a shorter wavelength side than the peak wavelength λ0 of FIG. As described above, 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 of the received light waveform W0 shown in FIG. 8 due to the peak Py does not affect the accurate specification of the peak wavelength λ0. Therefore, in the unnecessary component removal correction, a portion caused by the peak Py of the received light waveform W0 may not be removed from the received light waveform W0, or may be removed from the received light waveform W0. When the portion 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 portion 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 composed of a laser diode is excessively large with respect to the intensity suitable for measuring the displacement, the light of the wavelength component corresponding to the excitation light is unnecessary light. And Therefore, if the intensity of the excitation light emitted from the light source 121 is within a range suitable for measuring the displacement, the excitation light may be used for measuring the displacement.

  Another example of the 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 primary light separated by the diffraction grating 131, the zero-order light diffracted by the diffraction grating 131 (specular reflection in this example) is guided to the light receiving unit 140. In FIG. 11, the first-order light is indicated by a solid line, and the zero-order light is indicated by a chain line.

  FIG. 12 is a diagram illustrating a light receiving waveform W0 of light guided to the light receiving unit 140 in 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. Like the received light waveform W0 in FIG. 8, the portion of the received light 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 zero-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 the zero-order light is not received by the pixel corresponding to the measurement range MR (FIG. 4). Therefore, the zero-order light is not used for calculating 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, a portion caused by the peak Pz of the received light waveform W0 is not removed from the received light waveform W0. Or may be removed from the received light waveform W0.

(B) Light Received Waveform Shift Correction and Light Received Waveform Scale Correction In the following description, as described in the example of FIG. 7, light is emitted from the light projecting unit 120, reflected by the lens unit 220, and received by the light receiving unit 140. The unnecessary light is referred to as first unnecessary light. In addition, unnecessary light generated by the light source 121 and guided to the surface of the measurement target S while passing through the phosphor 122 is reflected without focusing on the surface of the measurement target S, and is received by the light receiving unit 140. This is called second unnecessary light. Further, as described in the example of FIG. 11, the zero-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 pixel 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 inclination 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 pixel associated in advance. is there. In this case, the measurement distance cannot be accurately calculated because the measurement result fluctuates with the temperature change. Therefore, the light reception waveform shift correction and the light reception waveform scale correction described below are performed. The light reception waveform shift correction is a process of correcting a shift on the wavelength axis of the light reception waveform W0 that depends on temperature. The light-receiving waveform scale correction is a process of correcting a scale on the wavelength axis of the light-receiving waveform W0 that depends on temperature.

  For example, as shown in FIG. 12, the received light waveform W0 when measuring the displacement of the measurement target S has a peak P0 depending on the displacement of the measurement target S and peaks corresponding to the first to third unnecessary lights, respectively. Px, Py, and 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 target 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-receiving waveform shift correction, at least one of the three peaks Px, Py, and Pz is used. In the received light waveform scale correction, at least two of the three peaks Px, Py, and Pz are used.

  In order to perform the light-receiving waveform shift correction, a wavelength at which the center of at least one of the peaks Px, Py, and Pz should appear is stored in advance in the storage unit 151 of FIG. 1 as a reference wavelength. The control unit 152 specifies 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 amount of shift of the received light waveform W0 on the wavelength axis by comparing the wavelengths of the specified peaks Px to Pz with the reference wavelength, and calculates the wavelength of the received light waveform W0 based on the calculated shift amount. Compensate for on-axis shifts. In FIG. 12, a dotted line indicates the received light waveform W0 after the shift of the received light waveform W0 on the wavelength axis is corrected.

  In order to perform the light-receiving waveform scale correction, the storage unit 151 previously stores, as a reference interval, a wavelength interval at which the center of at least two peaks Px, Py, and Pz should appear. The control unit 152 specifies the intervals between the peaks Px to Pz corresponding to the reference intervals stored in the storage unit 151. The control unit 152 calculates the shift of the scale on the wavelength axis of the received light waveform W0 by comparing the specified interval between the peaks Px to Pz with the reference interval, and based on the calculated shift of the scale, calculates the shift of 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 received light waveform shift correction and the received light waveform scale correction may be performed, or both may be performed. The light-receiving waveform shift correction and the light-receiving waveform scale correction are performed before the above-described 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 have been performed, the measurement distance can be calculated more accurately.

  The light receiving signal on which the unnecessary component removal correction, the light receiving waveform shift correction, and the light receiving waveform scale correction are performed by the control unit 152 is provided to the PC 600. In this case, the CPU 601 can measure the displacement based on the appropriately corrected light receiving 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 by the light projecting unit 120 is sequentially irradiated on a plurality of portions of the measurement target S by the light irradiation unit 1 in the measuring head 200. Chromatic aberration along the optical axis direction is generated by the lens unit 220 in the light irradiated on the measurement target S by the light irradiation unit 1. Light having chromatic aberration is converged by the lens unit 220.

  Light having a wavelength reflected while being focused on a plurality of portions of the surface of the measurement target S sequentially passes through the core 310 a of the optical fiber 314. The plurality of lights that have sequentially passed through the optical fiber 314 are sequentially guided to the light splitting unit 130 through the fiber connector 330, the optical fiber 319, the fiber coupler 320, and the optical fiber 312, and are split. The plurality of lights separated by the spectroscopy 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 electric light reception signal indicating the amount of light received for each wavelength output from the light receiving unit 140 is an average signal in which the intensities for each wavelength of a plurality of lights respectively corresponding to a plurality of portions are integrated. Thereby, the averaging process of a plurality of lights can be easily performed. The displacement of the measurement target S is calculated by the control unit 152 based on the light intensity after the averaging process.

  Light focused at a position different from the position of the surface of the measurement target S may pass through the optical fiber 314 due to irregular reflection on the surface of the measurement target S. Even in such a case, according to the above configuration, intensities of a plurality of lights passing through the optical fiber 314 for each wavelength are averaged in the averaging process. This cancels out light components that cause random measurement errors due to diffuse reflection. Furthermore, in the above configuration, before the displacement of the measurement target S is calculated, unnecessary light components including at least the base waveform BL are removed from the received light waveform W0 by the unnecessary component removal correction. As a result, it is possible to reduce an error in displacement of the measurement target S measured by the confocal displacement meter 500.

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

  Further, in the above configuration, the light-receiving waveform scale correction is performed before the unnecessary component removal correction. As the light receiving waveform scale correction, the temperature of the light receiving waveform W0 that depends on the temperature is determined based on at least two of the peaks Px, Py, and Pz respectively corresponding to the first to third unnecessary lights that do not depend on the displacement of the measurement target S. The scale on the wavelength axis is corrected. Thereby, it is possible to compensate for a change in the measurement result due to a shift in scale on the wavelength axis of the received light waveform W0 due to 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 measurement target S can be calculated efficiently.

  Further, in the present embodiment, the tip portion of the optical fiber 314 functions as a pinhole. In this case, there is no need to separately arrange pinholes. Thus, the configuration of the confocal displacement meter 500 can be made compact. As described above, by using the clad 310b of the optical fiber 314 as a light shielding part and using 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-blocking member having a pinhole formed in a plate having a light-blocking property may be arranged at the end of the optical fiber 314 on the measurement head 200 side.

  Further, in the present embodiment, the processing device 100 and the measurement head 200 are provided separately, and are optically connected by the light guide 300. Therefore, it becomes easy to use the measurement head 200 including the lens unit 220 that generates appropriate chromatic aberration or the lens unit 220 having an appropriate focal length according to the shape or arrangement of the measurement target S or the like. This makes it possible to more easily measure the displacement of the measurement target S.

  In addition, since the light guide unit 300 includes an optical fiber, the processing device 100 and the measurement head 200 can be disposed separately. The measuring head 200 has no heat source. Therefore, measurement head 200 can be arranged in various environments. Further, as 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 the light emitted from the light source 121 including the 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 target S while chromatic aberration is generated through the lens unit 220. Thereby, light of a plurality of wavelengths for measuring the displacement of the measurement target S can be easily generated.

  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 laser light emitted from the light source 121 to generate light having a plurality of wavelengths, the light generated by using an optical fiber is efficiently used. Can be extracted well. Further, by using an optical fiber, the extracted light can be efficiently supplied to the measuring head 200.

  In the light projecting unit 120, the light emitted from the light source 121 passes through the lens 124 and is collected on the phosphor 122. Thus, the amount of light incident on the phosphor 122 can be increased. Thereby, the amount of light of a plurality of wavelengths emitted from the phosphor 122 to the lens unit 220 increases. Therefore, even when the size of the irradiation region formed on the surface of the measurement target S is reduced, the amount of light passing through the core 310a of the optical fiber 314 is prevented from being significantly reduced. Therefore, 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. Further, the refractive lens 221 and the diffraction lens 222 are arranged so that the light output from the optical fiber 314 passes through the refractive lens 221 and the diffraction lens 222. In this case, the direction of the 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 increases. 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 illustrating 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 driving unit 240 are provided inside the housing 210 of the measurement head 200 as the light irradiation unit 1 of FIG.

  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 driving unit 240 is, for example, a hollow motor. 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 driving section 240 includes a cylindrical fixing section 241 and a cylindrical rotating shaft 242. The rotation shaft 242 is provided in a hollow part of the fixed part 241 so as to be concentric with the fixed part 241.

  The end of the optical fiber 314 is fixed to a hollow portion of the rotating shaft 242, for example, while being inserted into a ferrule (not shown). The flat plate member 230 is attached to the rotating shaft 242 in a state where the entrance surface 231 and the exit surface 232 are inclined with respect to a plane orthogonal to the optical axis of the optical fiber 314. With light emitted from the optical fiber 314, the rotation shaft 242 rotates. The rotation speed of the driving section 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 rotates. FIG. 15A shows an optical path of light at an initial time point. FIG. 15B illustrates an optical path of light at a point in time when a certain time has elapsed from the initial point in time (when the drive unit 240 has rotated 90 degrees from the initial point in time). FIG. 15C shows the optical path of the light at a point in time when a certain period of time has elapsed further from the point in FIG. 15B (at a point in time when the drive unit 240 has further rotated 90 degrees from the point in time in 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 in parallel with the optical axis of the optical fiber 314. Since the incident surface 231 of the flat member 230 is inclined with respect to the surface orthogonal to the optical axis of the optical fiber 314, the light incident on the incident surface 231 of the flat member 230 is inclined at an angle 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. Thus, it is possible to irradiate the measurement target S with light through the lens unit 220 of FIG. 14 while shifting the light.

  FIG. 16 is a diagram illustrating a region of the measurement target S to which light is irradiated by the measurement head 200 in FIG. As shown in FIG. 16, light is applied to an annular region on the surface of the measurement target S. Thus, an annular irradiation region IR is formed on the surface of the measurement target S. According to this configuration, the load on the physically operating portion of the light irradiation unit 1 is smaller than when light is irradiated on a linear region on the surface of the measurement target S. Thus, the life of the flat plate member 230 and the driving unit 240 can be extended. The outer diameter OD of the irradiation region IR can be determined by selecting the inclination angle, the thickness, the refractive index, and the like of the flat plate member 230. In this example, the outer diameter OD is, for example, 250 μm. As described above, since the outer diameter OD is very small, the user recognizes the irradiation region IR as a single point instead of an annular shape.

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

  At a plurality of different times during a period in which the drive unit 240 makes one rotation, the plurality of different portions of the measurement target S are irradiated with light. Thereby, at a plurality of time points, for example, a plurality of light reception waveforms W1 to W4 as shown in FIG. 5 can be obtained. Therefore, the light receiving unit 140 performs exposure during a period in which the driving unit 240 makes one rotation. In this example, the light receiving unit 140 continuously performs exposure, but the present invention is not limited to this. The light receiving section 140 may perform exposure intermittently.

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

  The outer diameter OD of the irradiation area IR is preferably 100 μm or more. In this case, light is reflected at a plurality of portions of a sufficiently large area on the surface of the measurement target S. Therefore, in the signal of the average distribution, a light component that generates a random measurement error due to diffuse reflection is sufficiently canceled. Thereby, the error of the displacement of the measurement 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 on the measurement target 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 which lowers the measurement accuracy occurs. Thus, the displacement of the measurement target S can be measured with higher accuracy.

  As described above, light is received by the light receiving unit 140 during a single exposure period while the drive unit 240 makes one rotation. After that, a light receiving 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 target S can be calculated efficiently.

(7) Modification 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 modified examples of the lens unit 220.

  As shown in FIG. 17A, the lens unit 220 in the first modification includes a diffraction lens 222 and an objective lens 223 without including the refractive lens 221 in FIG. As shown in FIG. 17B, the lens unit 220 according to the second modification includes a diffraction lens 222 and an objective lens 223 without including the refractive lens 221 in FIG. In the second modification, the positions of the diffraction lens 222 and the objective lens 223 in the first modification are opposite to those of the diffraction lens 222 and the objective lens 223 in the first modification.

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

  The lens may be a glass lens, a resin lens, or a glass lens having a surface coated with a resin. Glass lenses have high heat resistance. The resin lens can be manufactured at low cost. Glass lenses coated with resin can be manufactured relatively inexpensively and have relatively high heat resistance.

  The lens of the lens unit 220 that can be closest to the measurement target S is arranged, 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 manufacturing line such as a factory, the measuring head 200 is placed in an environment where moisture, oil, or the like exists. By forming the optical system of the portion exposed to the outside of the measurement head 200 from glass, the oil resistance, water resistance, and contamination resistance of the measurement head 200 can be improved.

  For the same reason as in the above example, when there is a part exposed to the outside in the lens unit 220, it is preferable that the exposed part is formed of glass. Note that if the entire lens unit 220 can be shielded from the atmosphere outside the measurement head 200, the refraction lens 221, the diffraction lens 222, the objective lens 223, or the doublet lens 224 is formed of resin instead of glass. Is also good. For example, in the examples of FIGS. 17A to 17D, a cover glass is provided below the lens unit 220 (the side of the measurement target S) in a state where the lens unit 220 is arranged in the housing 210. You may.

(8) Modified Example of Light Projecting Unit In the present embodiment, the light emitted from light source 121 and the central axis of ferrule 123 are arranged on a straight line, but the present invention is not limited to this. FIG. 18 is a diagram illustrating a modified example of the light projecting unit 120. As shown in FIG. 18, the light projecting unit 120 according to 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 reflection member 129. The lens 128 is disposed between the reflection member 129 and the ferrule 123. The phosphor 122 is applied to the reflection surface of the reflection 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 reflection member 129 as excitation light. The phosphor 122 absorbs the excitation light and emits fluorescence. Here, the excitation light transmitted without being absorbed by the phosphor 122 and the fluorescence from the phosphor 122 are mixed to generate light in a wide wavelength band. The generated light is reflected by the reflection surface of the reflection member 129, and is guided to the ferrule 123 through the lens 128. Thus, light is input to the optical fiber 311. In this configuration, the degree of freedom in arranging the optical elements is increased. Therefore, it is 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 by the light source 121. On the other hand, when the light amount of the light from the light source 121 is increased, the heat generated by the phosphor 122 is increased, so that the reflection efficiency of the reflecting member 129 is reduced and the emission of the fluorescence from the phosphor 122 is easily saturated. Therefore, the reflecting 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 the light generated by the light projecting unit 120 can be further increased.

(9) Modified Example of Dispersing Unit In the present embodiment, the diffraction grating 131 of the dispersing unit 130 has a reflection type, but the present invention is not limited to this. FIG. 19 is a diagram illustrating a modified example of the spectroscopy unit 130. As shown in FIG. 19, in a modification of the light splitting 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 split by the diffraction grating 131 passes through the lens 133 and is focused on a pixel position of the light receiving unit 140 which differs for each wavelength.

  In the spectroscopy unit 130 of this example, there may be a case where zero-order light passing straight through the diffraction grating 131 is generated. When the zero-order light is received by the light receiving section 140, the peak of the light-receiving waveform corresponding to the zero-order light can be used for the above-described light-receiving waveform shift correction and light-receiving waveform scale correction.

[2] Second Embodiment (1) Basic Configuration and Operation Principle of Confocal Displacement Meter A confocal displacement meter according to a first embodiment of the confocal displacement meter according to a second embodiment of the present invention. The 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 300.

  The measurement head 200 of FIG. 20 includes a plurality (four in this example) of optical fibers 393 to 396. Further, 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 on the housing 110 of the processing apparatus 100, and the fiber coupler 350 is provided on the housing 210 of the measurement head 200. The present invention is not limited to this. The fiber coupler 340 may be provided in a portion other than the housing 110 of the processing device 100, and the fiber coupler 350 may be provided in a portion other than the housing 210 of the measurement 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 by the light projecting unit 120 of the processing device 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 target S through the optical fibers 393 to 396 and the lens unit 220.

  Part of the light reflected on the surface of the measurement target 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. Light input to ports 353 to 356 is output from ports 351 and 352 and input to ports 343 and 344 of fiber coupler 340 through optical fibers 397 and 398. Light input to ports 343 and 344 is output from ports 341 and 342. The light output from the port 342 is guided to the spectral unit 130 through the optical fiber 392. Thereby, the displacement measurement processing 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 measuring 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 irradiates four different portions of the surface of the measurement target S while passing through the lens unit 220 while generating chromatic aberration. In this case, on the surface of the measurement target S, four irradiation regions respectively corresponding to the four optical fibers 393 to 396 are formed.

  FIG. 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 the 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 cladding 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, 398 in FIG. 20 have the same configuration as the optical fibers 393 to 396.

  The fiber unit 301 is arranged such that the center of its 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 arranged 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 arranged 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 310a (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, by disposing the cores 310a of the optical fibers 393 to 396 at positions substantially equidistant from the optical axis of the lens unit 220, the lens unit 220 for causing aberration along the optical axis direction is provided. Optical design can be easily performed. Here, the optical axis means not only the optical axis when the optical axes of the refraction lens 221, the diffraction lens 222, and the objective lens 223 substantially coincide with each other, but also the refraction lens 221, the diffraction lens 222, and the 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 located at four corners of a square. The diameter L1 of each core 310a is preferably 200 μm or less, 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 part of the surface of the measurement target S is irradiated with light.

  Of the light reflected at the four portions (irradiation regions) of the surface of the measurement target S, the light focused at the position of the surface of the measurement target S is input to the corresponding optical fibers 393 to 396, and is illustrated in FIG. It is led to the processing device 100. The light guided to the processing device 100 is received by the light receiving unit 140 while being split by the diffraction grating 131. Here, the distance L2 between the centers of the adjacent cores 310a is preferably at least three times the diameter L1. When the distance L2 is three times or more the diameter L1, the light reflected while being focused on a part of the surface of the measurement target S passes through the pinholes of the optical fibers 393 to 396 corresponding to the part, Almost no disturbance light passes through the pinholes of the other optical fibers 393 to 396 that do not correspond to the part.

  The distance L2 between the centers of the adjacent cores 310a is more preferably 5 times or more and 10 times or less the diameter L1. When the distance L2 is not less than 5 times and not more than 10 times the diameter L1, the light reflected while being focused on a part of the surface of the measurement target S is disturbed by another pinhole that does not correspond to the part. Passing is further suppressed. Further, since the plurality of lights are not largely separated, they can pass near the center of the lens unit 220. Therefore, almost no aberration such as coma which 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 focused and reflected by the four portions of the measurement target S and 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. They are mixed in the process until they are output from the optical fiber 392. After that, the mixed optical signal is converted into an electric signal by the light receiving unit 140 via the spectroscopy unit 130. That is, in this example, the averaging process is performed in the state of the optical signal.

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

  Thereby, when the waveform of the light receiving 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 receiving waveforms W1 to W4 in FIG. 5 can be obtained. Therefore, by specifying the peak wavelength λ0 of the received light waveform W0, the measurement distance can be specified more accurately.

(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 target S by the plurality of optical fibers 393 to 396 in the measurement head 200. Irradiated respectively. Light having a wavelength reflected while being focused on a plurality of irradiation areas of the measurement target S passes through a 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 spectral 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 while being guided to the spectroscopy unit 130. In this case, there is no need to perform an operation to generate an average distribution of the intensity for each wavelength of the 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 performed efficiently at high speed and efficiently.

  As shown in FIG. 20, the fiber coupler 340 is arranged on the processing device 100 side, and the fiber coupler 350 is arranged on the measurement head 200 side. The fiber couplers 340 and 350 are connected by optical fibers 397 and 398 having two cores 310a. According to this configuration, the degree of freedom in designing the arrangement of the fiber couplers 340 and 350 can be improved while suppressing the loss of the optical signal reflected from the measurement target 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 between the housing 210 and the optical fibers 393 to 396. By disposing the fiber coupler 350 in a strong housing (connector section) made of metal or the like, it is possible to prevent the measurement head 200 from increasing in size while fixing and protecting the fiber coupler 350. The fiber coupler 350 may be provided near the connector.

(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, 398, but the present invention is not limited to this.

  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 become unnecessary.

  Alternatively, the light guide unit 300 according to the second embodiment includes two 1 × 2 fiber couplers instead of the 2 × 4 fiber coupler 350, and the two fiber couplers are connected to the measurement head 200. It may be provided. In this case, in one fiber coupler, an optical fiber 397 is connected to one port, and optical fibers 393 and 394 are connected to two ports facing 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, the light guide unit 300 according to the second embodiment includes a 1 × 2 fiber coupler and a 1 × 4 fiber instead of the 2 × 2 fiber coupler 340 and the 2 × 4 fiber coupler 350. 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 measuring head 200. Optical fibers 391 and 392 are connected to two ports of a 1 × 2 type fiber coupler, and one end of an optical fiber 397 is connected to one port facing the two ports. Further, the other end of the optical fiber 397 is connected to one port of a 1 × 4 type fiber coupler, and 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 becomes unnecessary.

[3] Other Embodiments (1) In the first embodiment, the light guide unit 300 includes an optical fiber, and light is transmitted between the processing device 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 an optical element 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 measuring head 200 of FIG. 23 does not have the optical fiber 314 of FIGS. Further, the light guide unit 300 of the present embodiment is different from the optical fibers 311, 312, 319, the fiber coupler 320 and the fiber connector 330 of FIGS. 1 and 13 in that a half mirror 371 and a plurality of (two in this embodiment) spaces are provided. Filters 372 and 373 are included. Pinholes 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 372 a 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 target S through the flat plate member 230 and the lens unit 220. In this state, the flat plate member 230 is rotated by the driving unit 240 (not shown). As a result, light is applied to the annular region on the measurement target S. Part of the light reflected on the surface of the measurement target 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 light splitting unit 130. The light receiving unit 140 receives the light separated by the light separating unit 130 and outputs a light receiving signal.

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

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

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

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

  Alternatively, the light receiving unit 140 may receive a plurality of lights sequentially split by the spectroscopic unit 130 in a plurality of exposure periods, and output a light reception signal for the light received in 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 a plurality of light reception signals output from the light receiving unit 140 for each wavelength, and based on the calculated average signal. The displacement of the measurement target S can be calculated. According to these configurations, it is possible to perform a desired calculation in consideration of the intensities of a plurality of lights in calculating the average signal. Thereby, the displacement of the measurement target 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 unit 240 only needs to be able to rotate the flat plate member 230, and may be configured by a motor other than the hollow motor, one or more rotors, a belt, and the like.

  (4) In the first embodiment, light is coupled and branched using the fiber coupler 320, but the present invention is not limited to this. Instead of using the fiber coupler 320, the coupling and branching of light may be performed using a plurality of optical fibers 311, 312, and 319 in which a plurality of cores 310a 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 arranged at any position on the optical path.

  (6) In the second embodiment, the confocal displacement meter 500 is configured to irradiate light to four portions of the surface of the measurement target S, but the present invention is not limited to this. The confocal displacement meter 500 may be configured to irradiate two, three, or five or more portions of the surface of the measurement target S with light.

  Therefore, the number of optical fibers included in the fiber unit 301 is preferably two or more, and more preferably four 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, but the outer diameter of the fiber unit 301 increases. 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 fiber unit 301 may be arranged such that its center is separated from the optical axis of the lens unit 220.

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

  Further, the optical fibers 393 and 395 may be arranged so as to be displaced by a half of the distance L2 in the arrangement direction of the optical fibers 393 and 395 from the positions of the optical fibers 393 and 395 in FIG. In this case, the optical fibers 393 to 396 may be arranged such 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 coupling and branching are performed using a plurality of fiber couplers 340 and 350, but the present invention is not limited to this. Instead of using the fiber couplers 340 and 350, 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 such that four lights passing through the four optical fibers 393 to 396 are combined into one light while being guided to the light splitting 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 spectroscopy unit 130. Further, the light splitting unit 130 and the light receiving unit 140 may be configured such that the four lights split by the light splitting unit 130 are individually received by the light receiving unit 140.

  In this case, the light receiving unit 140 outputs four light receiving signals respectively corresponding to the four lights. Therefore, the control unit 152 calculates the average signal as the signal intensity for each wavelength by averaging or integrating the four light reception signals output from the light receiving unit 140 for each wavelength, and performs measurement 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 light separating 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. Note that, instead of using a two-dimensional line sensor as the light receiving unit 140, four one-dimensional line sensors may be used. Further, in the present example, four spectral units 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 while being guided to the light splitting unit 130. However, the present invention is not limited to this.

  In a process in which four lights passing through the optical fibers 393 to 396 are guided to the spectroscopy unit 130, one combined light of two lights and another combined light 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 light splitting unit 130 and the light receiving unit 140 may be configured such that the two combined lights split by the light splitting unit 130 are individually received by the light receiving unit 140.

  In this case, the light receiving unit 140 outputs two light receiving signals respectively corresponding to the two combined lights. Therefore, the control unit 152 calculates an average signal as a signal intensity for each wavelength by averaging or integrating the two light reception signals output from the light receiving unit 140 for each wavelength, and performs measurement 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 two combined lights separated by the light separating unit 130. In this case, two light receiving regions are set in the two-dimensional line sensor as one-dimensional line sensors respectively corresponding to the two combined lights. Note that instead of using a two-dimensional line sensor as the light receiving unit 140, two one-dimensional line sensors may be used. Further, in this example, two spectral units 130 may be provided so as to correspond to each of the two combined lights.

  (12) In the second embodiment, the light emitted by 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. Are guided to the light splitting 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 the light emitted by 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 reflected on the surface of the measurement target S and passing through the optical fibers 393 to 396 are sequentially output. The 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, the light receiving signal integrated during the exposure period is output from each pixel of the light receiving unit 140 after the end of the exposure. Accordingly, the light receiving 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 target 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 split by the spectroscopic unit 130 and output a light receiving 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 light receiving signals output from the light receiving unit 140 for each wavelength, and based on the calculated average signal. The displacement of the measurement target S can be calculated.

  (13) In the first and second embodiments, a laser diode that emits light of a single wavelength is used as the light source 121 of the light projecting unit 120 in FIGS. 6 and 18, but the present invention is not limited to this. Not done. 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 another wavelength band. For example, the light projecting unit 120 may emit light in an infrared region or may emit light in an 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 device 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 receiving signal acquired from the light receiving unit 140, measures the displacement of the measurement target S, and displays the measurement result on the sub-display unit. Displayed at 400. Further, control unit 152 provides a light receiving signal acquired from light receiving unit 140 to PC 600. On the other hand, the CPU 601 of the PC 600 executes a displacement measurement process of the measurement target 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 a displacement measurement process based on the displacement measurement program and various processes related to the displacement measurement result.

[4] Correspondence relationship between each component of the claims and each unit of the embodiment Hereinafter, an example of correspondence between each component of the claims and each unit of the embodiment will be described. 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 Are examples of an optical member, the tip of the optical fiber 314 or the pinhole 373a of the spatial filter 373 is an example of one pinhole, and the tips 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 the pinhole member.

  In addition, the spectroscopy unit 130, the light receiving unit 140, the arithmetic processing unit 150, the light guide unit 300, and the CPU 601 are examples of a displacement measurement unit. Unnecessary component removal correction is an example of a first correction process. This is an example of the second correction processing, in which the received light waveform scale correction is an example of the third correction processing, the peak Px is an example of the first peak, the peak Py is an example of the second peak, Pz is an example of the third peak.

  Further, 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 spectral unit 130 is an example of a spectral unit, and the light receiving unit. 140 is an example of a light receiving unit, the arithmetic processing unit 150 and the CPU 601 are examples of a calculating unit, the fiber couplers 340 and 350 are examples of a combining unit, the light emitting unit 1 is an example of a light emitting unit, and The region IR is an example of a region.

  Further, the processing device 100 is an example of a processing device, the measurement head 200 is an example of a head unit, the housing 110 is an example of a first housing, and the housing 210 is an example of a second housing. The lens 124 is an example of a light collecting member, the refraction lens 221 is an example of a refraction lens, and the diffraction lens 222 is an example of a diffraction lens.

  Various other elements having the configuration or function described in the claims can also be used as the components in the claims.

[5] Reference Embodiment (1) The confocal displacement meter according to the present reference embodiment is a confocal displacement meter that measures the displacement of a measurement object using a confocal optical system, and emits light having a plurality of wavelengths. A light projecting unit that emits light, an optical member that generates chromatic aberration along the optical axis direction in light emitted by the light projecting unit, and converges light having chromatic aberration and irradiates the measurement target with an optical member. Of the light applied to the object, a pinhole member having one or more pinholes for transmitting light having a wavelength reflected while being focused on the surface of the measurement object, and a plurality of portions of the measurement object. A displacement measuring unit that calculates displacement of the measurement target 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 that have been reflected and passed through the one or more pinholes. Equipped, the displacement measurement unit, Before calculating the displacement of the measurement object, the first signal is removed from the average signal so that at least a part of unnecessary components corresponding to unnecessary light except light reflected while being focused on the surface of the measurement object is removed. Is performed.

  In the confocal displacement meter, light having a plurality of wavelengths is emitted by the light projecting unit. In the light emitted by the light projecting unit, chromatic aberration occurs along the optical axis direction by the optical member. Further, light having chromatic aberration is converged by the optical member and is irradiated on the measurement target.

  Of the light applied to the measurement target by the optical member, light having a wavelength reflected while being focused on a plurality of portions of the surface of the measurement target 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 of the plurality of lights passing 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 the above configuration, intensities of the plurality of lights passing through one or more pinholes for each wavelength in the average signal are averaged. This cancels out light components that cause random measurement errors due to diffuse reflection. Further, the first correction processing is performed before the displacement of the measurement target is calculated, thereby eliminating unnecessary light corresponding to unnecessary light excluding light reflected while being focused on the surface of the measurement target from the average signal. At least some of the components are removed. As a result, it is possible to reduce errors in the displacement of the measurement object measured by the confocal displacement meter.

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

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

  (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 a light source including a laser diode and a light source. A condensing member for condensing light, and a fluorescent light provided at one end of the optical fiber for absorbing a part of the light condensed by the condensing member and emitting light having a plurality of wavelengths to the optical member through the optical fiber 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. Accordingly, the amount of light having a plurality of wavelengths generated from the phosphor increases.

  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 the light is optically transmitted from the other end of the optical fiber. The object to be measured is irradiated through the member. Therefore, even when the size of the irradiation region formed on the measurement target is reduced, the amount of light passing through one or more 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 at which the position of the average signal on the wavelength axis does not depend on the displacement of the measurement object, and the displacement measurement unit performs the processing on the wavelength axis of the average signal before the first correction processing. A second correction process for correcting a shift on the wavelength axis of the average signal depending on the temperature may be performed based on the position of the unnecessary peak in the above.

  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 of the average signal on the wavelength axis 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 fluctuation of the measurement result due to the temperature change. .

  (5) The unnecessary peak may include a first peak corresponding to the first unnecessary light 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 target, the position of the first peak on the wavelength axis of the average signal does not depend on the displacement of the measurement target. Therefore, by compensating for the shift of the average signal on the wavelength axis 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 the fluctuation of the measurement result due to the temperature change. it can.

  (6) The light projection 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 unnecessary peaks are generated by the light source. And a second peak corresponding to the second unnecessary light emitted to the optical member while passing through the phosphor.

  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, it is possible to compensate for the variation of the measurement result due to the temperature change by correcting the shift of the average signal on the wavelength axis depending on the temperature based on the position of the second peak on the wavelength axis of the average signal. it can.

  (7) The displacement measurement unit includes a spectroscopic unit that splits the light that has passed through one or more pinholes by diffracting the light, and the unnecessary peak corresponds to the third unnecessary light diffracted by the zeroth order in the spectroscopic unit. It may include a third peak.

  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, so that 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 target. Therefore, it is possible to compensate for the variation of the measurement result due to the temperature change by correcting the shift of the average signal on the wavelength axis depending on the temperature based on the position of the third peak on the wavelength axis of the average signal. it can.

  (8) 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, and the displacement measurement unit performs the processing of the average signal before the first correction processing. A third correction process for correcting a scale on the wavelength axis of the average signal depending on the temperature may be performed based on the positions of at least two unnecessary peaks on the wavelength axis.

  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. Thus, the spacing between two unwanted peaks on the wavelength axis of the average signal corresponds to a shift in scale on the wavelength axis of the average signal due to a change in temperature. Therefore, by compensating the scale of the average signal on the wavelength axis which is dependent on the temperature based on the positions of the two unnecessary peaks on the wavelength axis of the average signal, the fluctuation of the measurement result due to the temperature change is compensated. Can be.

  (9) 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 displacement measuring unit includes one or more And a light splitting unit that splits the light passing through the pinhole while reflecting the light. At least two unnecessary peaks are emitted from the light projecting unit, reflected by the optical member, and guided to the displacement measuring unit. , A second peak corresponding to the second unnecessary light emitted from the light source and emitted to the optical member while passing through the phosphor, and a third order diffracted by the zeroth order in the spectroscopic unit. At least two peaks among the third peaks corresponding to unnecessary light may be included.

  In this case, since the first unnecessary light does not reach the measurement target, the position of the first peak on the wavelength axis of the average signal does not depend on the displacement of the measurement target. 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 target. Since the third unnecessary light, which is the zero-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. Therefore, by correcting the scale on the wavelength axis of the average signal that depends on temperature based on the position of at least two peaks among the first to third peaks on the wavelength axis of the average signal, the temperature change Variations in measurement results can be compensated.

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

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

  (11) The displacement measuring unit includes a combining unit that combines the plurality of lights acquired by the plurality of light acquiring units to generate one combined light, and a spectroscopic unit that separates the combined light generated by the combining unit. A light receiving unit that receives light split by the light splitting unit, and outputs an electric light receiving signal indicating the intensity of 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 calculating unit that performs the first correction process on the average and calculates the displacement of the measurement target based on the corrected average signal.

  In this case, a plurality of lights 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 electric light receiving signal indicating the intensity for each wavelength output from the light receiving unit is an average signal obtained by integrating the intensities for a plurality of lights for each wavelength. 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 efficiently calculated at high speed.

  (12) The confocal displacement meter further includes a light irradiating unit that sequentially irradiates the light emitted by the light projecting unit to a plurality of portions of the measurement object, and the optical member irradiates the measurement object by the light irradiation unit. The chromatic aberration is generated while the chromatic aberration is converged, and the pinhole member includes one pinhole, and the one pinhole is reflected while being focused on a plurality of portions of the measurement target. The light of the wavelength is sequentially transmitted, and the displacement measurement unit is configured to determine the measurement target 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 sequentially passing through one pinhole. The displacement may be calculated.

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

  (13) The displacement measurement unit receives a plurality of lights sequentially separated by the spectroscopic unit and a plurality of lights sequentially separated by the spectroscopic unit within a single exposure period, and receives the received light. A light receiving unit that outputs an electric light receiving signal indicating the intensity of light for each wavelength as an average signal, and performs a first correction process on the average signal output from the light receiving unit, and performs measurement based on the corrected average signal. And a calculating unit for calculating the displacement of the object.

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

  (14) The displacement measurement unit sequentially disperses a plurality of lights sequentially passing through one pinhole, and sequentially receives the plurality of lights sequentially dissociated by the dispersing unit, and outputs the plurality of lights sequentially received. Calculates the average signal as the signal intensity for each wavelength by averaging or integrating for each wavelength the light receiving unit that outputs an electrical light receiving signal indicating the intensity for each wavelength and the multiple light receiving signals output from the light receiving unit 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 target 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. The average signal is calculated by averaging or integrating a plurality of light receiving signals output from the light receiving unit for each wavelength by the calculating unit. According to this configuration, in the calculation of the average signal, a desired average or integration can be performed in consideration of the intensities of a plurality of lights. 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 target, and the light irradiating unit is configured to irradiate the plurality of portions on the annular region on the surface of the measurement target with light. Alternatively, the optical axis of the light emitted by the light projecting unit may be shifted along the surface of the measurement target.

  According to this configuration, the burden on the physically operating portion of the light irradiation section is smaller than when a plurality of portions on the linear region on the surface of the measurement target are irradiated with light. Thereby, the life of the light irradiation part can be prolonged.

  (16) The optical member includes 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 such that light emitted from the light projecting portion passes therethrough.

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

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

Reference Signs List 1 light irradiation unit 100 processing device 110, 210 housing 120 light emitting unit 121 light source 122 phosphor 123 ferrule 124, 128, 132, 133 lens 125 holder 126 filter element 127 element holder 127A light source fixing unit 127B ferrule fixing unit 127C lens Fixed unit 129 Reflecting member 130 Beam splitting unit 131 Diffraction grating 140 Light receiving unit 150 Arithmetic processing unit 151 Storage unit 152 Control unit 160 Power supply unit 200 Measurement head 220 Lens unit 221 Refractive lens 222 Diffractive lens 223 Objective lens 224 Doublet lens 230 Flat plate member 231 Incident surface 232 Outgoing surface 240 Drive unit 241 Fixed unit 242 Rotation axis 300 Light guide unit 301 Fiber unit 302 Holding member 310a Core 310b Cladding 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 port 324, 333, 345, 357 main body 330 fiber connector 371 half mirror 372, 373 spatial filter 372a, 373a pinhole 400 sub display unit 491 switching 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 focus position PD multi-division RP reference position S measurement target W0 , W1, W2, W3, W4 Reception waveform λ0 to λ4, λx, λy Peak wavelength

(1) A confocal displacement meter according to the present invention is a confocal displacement meter that measures a displacement of an object to be measured using a confocal optical system, and includes 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, and the optical member irradiates the measurement object. of the light, the measurement object and the pinhole member having Lupi Nhoru passes light of reflected while focusing on the surface of the measurement object wavelength, by which light is irradiated to the measurement object from the optical member in about the light having a plurality of wavelengths spent through the pinhole after being reflected and a displacement measuring unit for calculating a displacement of the measurement object based on the signal strength of each wavelength of the received light signal, the displacement measuring unit , before calculating the displacement of the measurement object, Performing a first correction process so that at least a part of the optical signal or found unnecessary components are removed, at least a portion of the undesired component, the displacement measuring unit is reflected by the optical member while being emitted from the light projecting unit And the position of the received light signal on the wavelength axis includes a first peak that does not depend on the displacement of the measurement target .

Passing by light irradiation to the measurement object from the optical member, among the irradiated onto the measurement object light, the light reflected while focusing at the front surface of the measurement object is a pinhole of the pinhole member Spend . Displacement of the measurement object based on signal intensity of each wavelength of the light passing through the pinhole is calculated.

Before the displacement of the total measurement object is calculated, unnecessary components corresponding to unnecessary light except light reflected while focusing on the surface of the measurement object from the average signal by the first correction processing is performed Is removed at least in part. As a result, it is possible to reduce the error of the displacement of the measurement object measured by confocal displacement meter.

Further, in the above configuration, at least a part of the unnecessary component is emitted from the light projecting unit, is reflected by the optical member, is guided to the displacement measuring unit, and the position of the light receiving signal on the wavelength axis is measured. A first peak that does not depend on the displacement of In this case, components emitted from the light projecting unit and reflected by the optical member and guided to the displacement measuring unit are removed, so that errors in displacement of the measuring object can be further reduced.

(2) The confocal displacement meter further includes a processing unit, a head unit, and a light guide unit connecting the processing unit and the head unit, and the processing unit accommodates a part of the displacement measuring unit and the light projecting unit. further comprising a first housing, the head section may further include a second housing for accommodating the optical engine material and pinhole member, the light guide portion guides the light emitted by the light projecting unit to the optical member At least a part of the light guide may be a part of the displacement measurement unit that is not accommodated in the first housing.

In this case, a processing device including a part of the light projecting unit and the displacement measuring unit and a head unit including the optical member and the pinhole member are separately provided via the light guiding unit . Therefore, it becomes easy to use a head unit including an optical member that generates appropriate chromatic aberration or an optical member having an appropriate focal length according to the shape or arrangement of the measurement target. Thereby, the displacement of the measurement object can be more easily measured.
(3) The pinhole member includes first to fourth pinholes as pinholes, and the first to fourth pinholes may be respective cores of the second to fifth optical fibers.
(4) The light guide may include first to fourth optical fibers.
(5) The confocal displacement meter is a head including a processing device including a first housing accommodating a part of a displacement measuring unit and a light projecting unit, and a second housing accommodating an optical member and a pinhole member. And a light guide unit that connects the processing unit and the head unit, guides light emitted by the light projecting unit to the head unit, and guides light having a plurality of wavelengths from the head unit to the processing device. , The head section includes, as a pinhole member, first to fourth optical fibers, each core of which forms a first to fourth pinhole, and the displacement measuring section includes first to fourth optical fibers. The displacement of the object to be measured may be calculated based on the signal intensity for each wavelength of the received light signal with respect to the light having a plurality of wavelengths mixed by the fiber coupler via.
(6) The fiber coupler may be housed in the first housing of the processing device.
(7) The first to fourth pinholes may be arranged symmetrically with respect to the optical axis of the optical member.
(8) The first to fourth pinholes may be separated by substantially the same distance from the optical axis of the optical member.

( 9 ) The light projecting unit includes a light source composed of a laser diode, a light condensing member for condensing light generated by the light source, and one end of the light condensed by the light condensing member provided at one end of the light guiding unit. A phosphor that absorbs the light and emits light having a plurality of wavelengths to the optical member through the light guide .

Further, according to the above configuration, since the phosphor is provided at one end of the light guide section , light having a plurality of wavelengths efficiently enters the one end of the light guide section from the phosphor, and the other light guide section has a different wavelength. The object to be measured is irradiated from the end through the optical member. Therefore, in case of reducing the size of the irradiated region formed on the measurement object is also prevented from the amount of light passing through the pinhole is remarkably lowered. As a result, the size of the irradiation area can be reduced.

( 10 ) Before the first correction processing, the displacement measurement unit corrects the shift of the average signal on the wavelength axis depending on the temperature based on the position of the unnecessary component on the wavelength axis of the average signal. 2 may be performed.

Since the light emitted from the light emitting unit and reflected by the optical member and guided to the displacement measurement unit does not reach the measurement target, the position of the first peak on the wavelength axis of the received light signal is determined by the position of the measurement target. It does not depend on displacement. Therefore, the position of the first peak on the wavelength axis of the received light signal does not depend on the displacement of the measurement target, but changes depending on the temperature. Therefore, the position of the first peak on the wavelength axis of the light receiving signal corresponding to the shift on the wavelength axis of the light receiving signal due to a change in temperature. Therefore, the variation of the measurement result due to the temperature change is compensated by correcting the shift on the wavelength axis of the received light signal depending on the temperature based on the position of the first peak on the wavelength axis of the average signal. Can be.

( 11 ) 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 at least a part of the unnecessary component includes: it may include a second peak that will be emitted to the optical member while passing through the generator has been phosphor by the light source.

In this case, since the light generated by the light source and emitted to the optical member while passing through the phosphor has a specific wavelength, the position of the second peak on the wavelength axis of the received light signal is caused by the displacement of the measurement object. Does not depend. Therefore, based on the position of the second peak on the wavelength axis of the received light signal, by correcting the shift in the wavelength axis of the light receiving signal dependent on temperature, to compensate for the variations in measurement results due to a temperature change it can.
(12) The second peak may be steeper than the first peak.
(13) The first peak may have a smoother shape than the peak of the received light signal that depends on the displacement of the measurement target.

(14) displacement measuring unit includes a spectral unit for the spectral by diffracting the light passing through the pinhole, at least a portion of the undesired component may comprise a third peak that will be zero-order diffracted by the spectroscopic portion .

In this case, the position of the third peak on the wavelength axis of the light receiving signal does not depend on the wavelength of the light 0-order diffracted by the spectroscopic unit. Therefore, the position of the third peak on the wavelength axis of the received light signal does not depend on the displacement of the measurement target. Therefore, based on the position of the third peak on the wavelength axis of the received light signal, by correcting the shift in the wavelength axis of the light receiving signal dependent on temperature, to compensate for the variations in measurement results due to a temperature change it can.

(15) The optical member has a refraction lens, and a diffraction lens, a refractive lens and a diffractive lens may be arranged to pass light emitted from the light projecting unit.

In this case, the direction of the chromatic aberration generated by each lens is the same in each lens, and as a result, the chromatic aberration on the optical axis of the optical member increases. Thus, the range that can be measured by the confocal displacement meter can be increased.
(16) At least a part of the unnecessary component may be light that is emitted from the light projecting unit, reflected by the optical member before passing through the diffraction lens, and guided to the displacement meter side.

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 There are examples of the optical member, pinhole 373 a of the tip portion or the spatial filter 373 of the optical fiber 314, an example of the distal end portion Gapi Nhoru optical fiber 393 to 396, the optical fiber 314,393～396 or spatial filter 373 Ri example der pinhole member, core 310a of the optical fiber 393 to 396 are examples of the first to fourth pinhole respectively, optical fibers 393 to 396 is the first to fourth optical fibers respectively It is an example, fiber coupler 340 and 350 Ru example der of fiber coupler.

In addition, the spectroscopy unit 130, the light receiving unit 140, the arithmetic processing unit 150, the light guide unit 300, and the CPU 601 are examples of a displacement measurement unit. Unnecessary component removal correction is an example of a first correction process. Ru example der of the second correction processing.

The optical fibers 311, 312, 314 , 319, 391 to 396, 397, and 398 are examples of a light guide , the light source 121 is an example of a light source, the phosphor 122 is an example of a phosphor, and 130 is an example of the spectral portion.

Claims (15)

A confocal displacement meter that measures a displacement of a measurement object using a confocal optical system,
A light emitting unit that emits light having a plurality of wavelengths,
An optical member that generates chromatic aberration along the optical axis direction in light emitted by the light projecting unit, and irradiates the object to be measured by converging light having chromatic aberration.
A pinhole member having one or a plurality of pinholes for transmitting light having a wavelength reflected while being focused on the surface of the measurement target, among light emitted to the measurement target by the optical member,
The plurality of lights or the plurality of lights sequentially passing through one pinhole after being sequentially reflected by the plurality of portions of the measurement target by being sequentially irradiated with the plurality of portions of the measurement target from the optical member. By simultaneously irradiating a plurality of portions of the measurement object from the optical member with light, the plurality of light beams are simultaneously reflected by the plurality of portions of the measurement object, respectively, and then simultaneously pass through a plurality of pinholes for each wavelength. A displacement measurement unit that calculates displacement of the measurement target based on the signal intensity of each wavelength of the average signal corresponding to the average of the intensity of
The displacement measurement unit may calculate at least one of unnecessary components corresponding to unnecessary light excluding light reflected while being focused on the surface of the measurement target from the average signal before calculating the displacement of the measurement target. A first correction process is performed so that the part is removed,
At least a part of 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 target,
The confocal displacement meter, wherein the unnecessary peak includes a first peak corresponding to first unnecessary light emitted from the light projecting unit, reflected by the optical member, and guided to the displacement measuring unit. A processing unit;
Head part,
Further comprising 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 emitting unit and houses a part of the displacement measuring unit and the light emitting unit,
The head unit further includes a second housing that includes the optical member and the pinhole member and houses the optical member and the pinhole member,
The optical fiber guides 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 part of the displacement measurement unit that is not housed 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 emitting unit is
A light source comprising a laser diode,
A light-collecting member that collects light generated by the light source,
A phosphor that is provided at one end of the optical fiber and absorbs a 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 6. A confocal displacement meter according to Item 2. The displacement measuring unit corrects a shift on the wavelength axis of the average signal depending on temperature based on a position of the unnecessary peak on the wavelength axis of the average signal before the first correction process. The confocal displacement meter according to claim 1, wherein a second correction process is performed. The light emitting unit is
Light source,
A phosphor that emits light having a plurality of wavelengths to the optical member by absorbing a part of the light generated by the light source,
5. The unnecessary peak according to claim 1, wherein the unnecessary peak includes a second peak corresponding to a second unnecessary light emitted from the light source and emitted to the optical member while passing through the phosphor. 5. The confocal displacement meter according to 1. The displacement measurement unit includes a spectroscopy unit that splits light that has passed through the one or more pinholes by diffracting the light,
The confocal displacement meter according to any one of claims 1 to 5, wherein the unnecessary peak includes a third peak corresponding to third unnecessary light diffracted by the zeroth order in the spectroscopic unit. The unnecessary component includes at least two of the unnecessary peaks,
Before the first correction process, the displacement measurement unit is configured to determine the temperature-dependent average signal on the wavelength axis based on the positions of the at least two unnecessary peaks on the wavelength axis of the average signal. 5. The confocal displacement meter according to claim 1, wherein a third correction process for correcting a scale is performed. The light emitting unit is
Light source,
A phosphor that emits light having a plurality of wavelengths to the optical member by absorbing a part of the light generated by the light source,
The displacement measurement unit includes a spectroscopy unit that performs spectroscopy while reflecting light passing through the one or more pinholes,
The at least two unnecessary peaks are a first peak, a second peak corresponding to a second unnecessary light emitted from the light source and emitted to the optical member while passing through the phosphor, and The confocal displacement meter according to claim 7, wherein the confocal displacement meter includes at least two peaks among third peaks corresponding to third unnecessary light diffracted by the 0th order at the portion. The pinhole member includes a plurality of pinholes,
The displacement measuring unit,
The displacement according to any one of claims 1 to 5, wherein the displacement of the measurement target is calculated based on a signal intensity for each wavelength of an average signal corresponding to an average of the intensity for each of the plurality of lights. Confocal displacement meter. The displacement measuring unit,
A combining unit that generates one combined light by combining the plurality of lights;
A spectroscopy unit that splits the combined light generated by the combining unit,
A light receiving unit that receives the light separated by the light splitting unit and outputs an electric light receiving signal indicating an intensity for each wavelength of the combined light generated by the combining unit as an average signal;
The confocal device according to claim 9, further comprising: a calculating unit that performs the first correction process on the average signal output from the light receiving unit and calculates a displacement of the measurement target based on the corrected average signal. Displacement gauge. A light irradiating unit that sequentially irradiates the plurality of portions of the measurement target with light emitted by the light projecting unit,
The optical member generates chromatic aberration in the light irradiated on the measurement target by the light irradiation unit, and converges the light having the chromatic aberration,
The pinhole member includes one pinhole,
The one pinhole sequentially passes light of a wavelength reflected while being focused on the plurality of portions of the measurement object,
The displacement measuring unit,
The displacement of the measurement object is calculated based on the signal intensity for each wavelength of an average signal corresponding to the average of the intensity for each wavelength of the plurality of lights sequentially passing through the one pinhole. 10. The confocal displacement meter according to any one of claims 7 to 9. The displacement measuring unit,
A spectroscopy unit for sequentially separating the plurality of lights sequentially passing through the one pinhole,
A light receiving unit that receives the plurality of lights sequentially separated by the light separating unit within a single exposure period, and outputs an electric light receiving signal indicating an intensity for each wavelength of the received light as an average signal,
The confocal displacement according to claim 11, further comprising: a calculating unit that performs the first correction process on the average signal output from the light receiving unit and calculates a displacement of the measurement target based on the corrected average signal. Total. The displacement measuring unit,
A spectroscopy unit for sequentially separating the plurality of lights sequentially passing through the one pinhole,
A light receiving unit that sequentially receives the plurality of lights sequentially split by the splitting unit and outputs an electric light receiving signal indicating an intensity for each wavelength for each of the plurality of sequentially received lights;
An average signal is calculated as the signal intensity for each wavelength by averaging or integrating the plurality of light receiving signals output from the light receiving unit for each wavelength, and the plurality of light receiving signals output from the light receiving unit or the calculated average The confocal displacement meter according to claim 11, further comprising: a calculating unit that performs the first correction process on a signal and calculates a displacement of the measurement target based on the corrected average signal. The plurality of portions are located on an annular region on the surface of the measurement target,
The light irradiating unit emits the light emitted by the light projecting unit along the surface of the measurement target so that the light irradiates the plurality of portions on the annular region on the surface of the measurement target. The confocal displacement meter according to any one of claims 11 to 13, wherein the confocal displacement meter is configured to shift by a shift. The optical member,
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 14, 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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