JP6767753B2 - Chromatic confocal sensor and measurement method - Google Patents

Description

The present invention relates to a chromatic confocal sensor and a measurement method using the same.

Conventionally, a chromatic confocal technique has been used to measure the height of an object to be measured. For example, Patent Document 1 discloses a chromatic confocal displacement meter (hereinafter referred to as a chromatic sensor) as shown in FIG. In this chromatic sensor, the color focused on the work changes on a one-to-one basis according to the height (displacement) of the work. By extracting light of a color that focuses on the work and specifying the color (light wavelength), the height of the work that is one-to-one with the color is measured (Patent Document 1 specification paragraph [0002]. [0003] etc.).

The chromatic sensor described in Patent Document 1 utilizes the fact that a phase difference (optical path difference) corresponding to a light wavelength is generated between polarized components perpendicular to each other passing through a wave plate made of a birefringent crystal or the like. The light wavelength is specified. This makes it possible to perform measurements that simultaneously satisfy long working distances, fine measurement spots, small errors due to inclination, high resolution, and high-speed response (paragraphs [0030] and [0035] in the specification of Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-39026

As described above, the chromatic sensor is required to be able to measure the position of the object to be measured with high accuracy based on the wavelength of the measurement light that is focused and reflected on the object to be measured. For that purpose, it is required to detect the wavelength of the measurement light or the parameter corresponding to the wavelength with high accuracy.

In view of the above circumstances, an object of the present invention is a chromatic confocal that can calculate the position of the object to be measured with high accuracy based on the wavelength of the measurement light reflected by the object to be measured at the in-focus position. The purpose is to provide a sensor and a measuring method.

In order to achieve the above object, the chromatic confocal sensor according to one embodiment of the present invention includes a light source unit, an optical head, a spectroscope, and a signal processing / control unit.
The light source unit emits a plurality of lights having different wavelengths.
The light source head has an objective lens that converges each of the plurality of lights to different focusing positions, and among the plurality of lights, the light reflected by the object to be measured at the focusing position is measured. Select as.
The spectroscope includes a diffraction grating that divides the selected measurement light into a plurality of diffracted lights, and a sensor that receives at least two or more diffracted lights among the plurality of diffracted lights.
The signal processing / control unit calculates the position of the object to be measured based on the difference between the light receiving positions of the two or more diffracted lights received by the sensor.

In this chromatic confocal sensor, the measurement light reflected by the object to be measured in the in-focus position is divided into a plurality of diffracted lights. Then, the position of the object to be measured is calculated based on the difference between the light receiving positions of the two or more diffracted lights received by the sensor. Therefore, for example, even if the position where the diffraction grating or the sensor is arranged is displaced, the displacement can be absorbed by using the difference between the light receiving positions of the two or more diffracted lights. As a result, the position of the object to be measured can be calculated with high accuracy.

The two or more diffracted lights may include at least two of the + 1st, 0th, and -1st order diffracted lights.
By using the +1st order, 0th order, and -1st order diffracted light, the position of the object to be measured can be calculated accurately.

The signal processing / control unit may calculate the position of the object to be measured based on the difference between the light receiving positions of the +1st order and the -1st order diffracted light.
The position of the object to be measured can be calculated accurately by using the difference in the light receiving position of the ± 1st order diffracted light.

The signal processing / control unit determines the object to be measured based on the difference between the light receiving position of either the +1 or -1st order diffracted light and the light receiving position of the 0th order diffracted light. The position of may be calculated.
By using either of the ± 1st-order diffracted light and the 0th-order diffracted light, the device can be miniaturized.

The signal processing / control unit is the sum of the difference in the light receiving positions of the + 1st and 0th order diffracted light and the difference in the light receiving positions of the -1st and 0th order diffracted light. The position of the object to be measured may be calculated based on the above.
The measurement accuracy can be improved by using the three diffracted lights.

The light source unit may emit white light including the plurality of lights.
This makes it possible to improve the measurement accuracy.

The measuring method according to one embodiment of the present invention includes emitting light including a plurality of lights having different wavelengths.
Each of the plurality of lights is focused on different focusing positions.
Of the plurality of lights, the light reflected by the object to be measured at the in-focus position is selected as the measurement light.
The selected measurement light is divided into a plurality of diffracted lights, and at least two or more of the diffracted lights are received by the sensor.
The position of the object to be measured is calculated based on the difference between the light receiving positions of the two or more diffracted lights received by the sensor.

As described above, according to the present invention, it is possible to calculate the position of the object to be measured with high accuracy based on the wavelength of the measurement light reflected by the object to be measured at the in-focus position. The effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.

It is a schematic diagram which shows the structural example of the chromatic confocal sensor which concerns on 1st Embodiment. It is an enlarged view of the optical head shown in FIG. It is an enlarged view of the spectroscope shown in FIG. It is a flowchart which shows the calculation example of the position of the object to be measured by the control part. It is a figure for demonstrating the structure of the spectroscope of the chromatic sensor given as a comparative example, and the measurement method using this. It is a figure for demonstrating the structure of the spectroscope of the chromatic sensor which concerns on 2nd Embodiment, and the measurement method using this. It is a figure for demonstrating the structure of the spectroscope of the chromatic sensor which concerns on 3rd Embodiment, and the measurement method using this.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic view showing a configuration example of a chromatic confocal sensor according to the first embodiment of the present invention. In the following description, the chromatic confocal sensor will be simply referred to as a chromatic sensor.

The chromatic sensor 100 includes an optical head 10, a controller 20, and an optical fiber unit 30. The controller 20 includes a light source unit 40, a spectroscope 50, and a signal processing / control unit (hereinafter, simply referred to as a control unit) 60.

The optical fiber section 30 has a fiber splitter 31. The fiber splitter 31 branches the light introduced from the optical fiber 32a and leads it out to each of the optical fibers 32b and 32c. On the other hand, the light introduced from each of the optical fibers 32b and 32c is led out to the optical fiber 32a. As shown in FIG. 1, the optical head 10 is connected to the optical fiber 32a, and the light source unit 40 and the spectroscope 50 are connected to the optical fibers 32b and 32c, respectively. An optical fiber coupler may be used instead of the fiber splitter 31.

FIG. 2 is an enlarged view of the optical head 10 shown in FIG. The optical head 10 has a pen-shaped housing portion 11 having an optical axis A1 in the longitudinal direction, and an objective lens 12 provided in the housing portion 11. The optical fiber 32a is connected to substantially the center of the rear end portion 11b of the housing portion 11. The light emitted from the optical fiber 32a passes through the objective lens 12 and is emitted from the front end portion 11a of the housing portion 11 toward the object O to be measured.

As shown in FIG. 2, the objective lens 12 is a lens having a large chromatic aberration, and the light emitted from the optical fiber 32a is converged to the focusing position P corresponding to the wavelength λ on the optical axis A1. In the present embodiment, white light W including a plurality of visible light having different wavelengths from the blue wavelength region to the red wavelength region is emitted from the optical fiber 32a toward the objective lens 12. The objective lens 12 converges each of the plurality of visible lights contained in the white light W to different focusing positions P according to the wavelength λ.

In FIG. 2, a plurality of visible lights dispersed by the objective lens 12 are shown from the objective lens 12 toward the front side (lower side in the drawing). Here, three colors of RGB light are shown as representatives. In this embodiment, the plurality of visible lights correspond to a plurality of lights having different wavelengths.

The wavelength λ1 and the focusing position P1 represent the wavelength and the focusing position of the visible light having the shortest wavelength among the plurality of visible lights, and the blue light B corresponds to this embodiment. The wavelength λn and the focusing position Pn represent the wavelength and the focusing position of the visible light having the longest wavelength among the plurality of visible lights, and the red light R corresponds to this embodiment. The wavelength λk and the focusing position Pk represent the wavelength and the focusing position for any visible light among a plurality of visible lights, and in FIG. 2, the green light G is exemplified (k = 1 to n). Is).

Further, the objective lens 12 converges the visible light reflected by the object O to be measured at the focusing position Pk on the optical fiber 32a. Therefore, the optical fiber 32a connected to the rear end portion 11b of the housing portion 11 is located at the confocal position when the visible light focused and reflected on the object O to be measured is converged by the objective lens 12. Be connected. This makes it possible to select the visible light reflected by the object O to be measured at the in-focus position Pk among the plurality of visible lights as the measurement light M.

In FIG. 2, three colors of RGB light reflected by the object O to be measured are shown between the objective lens 12 and the optical fiber 32a. In the example shown in FIG. 2, the object O to be measured exists at the focusing position (the focusing position of the green light G in the drawing). Therefore, the green light G reflected by the object O to be measured is converged on the optical fiber 32a. As a result, the green light G is selected as the measurement light M. In this way, the wavelength of the measurement light M and the position of the object to be measured O on the optical axis A1 have a one-to-one correspondence.

The optical system according to the present embodiment is realized by the housing portion 11, the optical fiber 32a and the objective lens 12 arranged in the housing portion 11 in a predetermined positional relationship. The configuration that functions as the optical system is not limited. For example, a pinhole or the like may be used to select the measurement light M. Further, in addition to the objective lens 12, another lens such as a collimator lens may be used.

The light source unit 40 shown in FIG. 1 emits white light W. The specific configuration of the light source unit 40 is not limited, and a solid light source such as an LED or an arbitrary light source 41 such as a mercury lamp may be used. The white light W emitted from the light source unit 40 is emitted into the optical head 10 via the optical fiber 32b, the fiber splitter 31, and the optical fiber 32a.

FIG. 3 is an enlarged view of the spectroscope 50 shown in FIG. The spectroscope 50 is a block for detecting the wavelength of the measurement light M transmitted from the optical head 10 to the optical fiber 32a. The measurement light M is irradiated into the spectroscope 50 via the optical fiber 32a, the fiber splitter 31, and the optical fiber 32c.

The spectroscope 50 includes a collimator lens 51, a diffraction grating 52, an imaging lens 53, a light-shielding plate 54, and a linear sensor 55. As shown in FIG. 3, these members are arranged so as to be orthogonal to the optical axis A2 (central axis of the luminous flux) of the measurement light M emitted from the optical fiber 32c, and their central portions are located on the optical axis A2. Arranged to do.

The collimator lens 51 irradiates the diffraction grating 52 with the measurement light M emitted from the optical fiber 32c substantially uniformly.

The diffraction grating 52 divides the measurement light M into a plurality of diffracted lights L. The diffraction grating 52 typically causes two ± nth-order diffracted lights L to appear at positions substantially symmetrical with respect to the 0th-order diffracted light. The specific configuration of the diffraction grating 52 is not limited, and any one may be used.

The imaging lens 53 can form a spot-like image of each of the plurality of diffracted lights L generated by the diffraction grating 52 on the linear sensor 55. In the present embodiment, the + 1st, 0th, and -1st order diffracted lights L1, L0, and L2 emitted from each of the diffraction gratings 52 (each slit) are incident on the imaging lens 53 and are linear sensors. It is emitted toward 55. In FIG. 3, only diffracted light from the three grids is shown for simplification.

The light-shielding plate 54 shields the 0th-order diffracted light L0 emitted from the imaging lens 53 toward the linear sensor 55. Therefore, in the present embodiment, two ± primary diffracted lights L1 and L2 are imaged on the linear sensor 55.

The linear sensor 55 has a plurality of pixels (light receiving elements) 56 arranged in one direction. Each pixel 56 outputs a signal corresponding to the intensity of the received light. The specific configuration of the linear sensor 55 is not limited, and for example, a C-MOS line sensor, a CCD line sensor, or the like is used.

The imaging lens 53 shown in FIG. 3 is a lens having small chromatic aberration, and forms ± primary diffracted lights L1 and L2 in a spot shape on the linear sensor 55 regardless of the wavelength of the measurement light M. be able to. On the other hand, the emission angle of each diffracted light L emitted from the diffraction grating 52 depends on the wavelength of the measured light M. Therefore, the position of the spot on the linear sensor 55 is a parameter corresponding to the wavelength of the measurement light M.

In the present embodiment, the linear sensor 55 corresponds to a sensor that receives at least two or more diffracted lights out of a plurality of visible lights. Further, the detection unit according to the present embodiment is realized by the diffraction grating 52 and the linear sensor 55.

The signal output by the linear sensor 55 is transmitted to the control unit 60 shown in FIG. 1 via the signal cable 57. A light-shielding mechanism or the like may be provided in the spectroscope 50 so that diffracted light other than ± primary diffracted light L1 and L2 does not enter the linear sensor 55.

The control unit 60 functions as a calculation unit in the present embodiment, and calculates the position of the object to be measured O based on the signal received from the linear sensor 55. For example, the optical head 10 is held at a predetermined reference position, and a plurality of visible lights are emitted to the object O to be measured. Then, based on the signal from the linear head 55, the position of the object to be measured O with reference to the reference position is calculated. Not limited to this, the position information of the optical head 10 may be acquired and the position information may be used to calculate the position of the object O to be measured.

Further, the distance from the optical head 10 to the object to be measured O may be calculated as the position of the object to be measured O. Further, even when the object to be measured O moves, it is possible to calculate the amount of movement of the object to be measured O based on the signal from the linear sensor 55 output in response to the movement (for example, in FIG. 2). See arrow Y).

When the optical head 10 is used from above the object O to be measured, the height of the object O to be measured is calculated as the position of the object O to be measured. Of course, the present invention is not limited to this, and the optical head 10 may be used in any direction and the position in that direction may be calculated.

The control unit 60 can be realized by, for example, a microcomputer (microcomputer) in which a CPU, a memory (RAM, ROM), an I / O (Input / Output), and the like are housed in one chip. Various processes by the microcomputer are executed by operating the CPU in the chip according to a predetermined program stored in the memory. Not limited to this, other ICs (integrated circuits) or the like may be appropriately used in order to realize the control unit 60.

FIG. 4 is a flowchart showing an example of calculating the position of the object O to be measured by the control unit 60. First, a description will be given with reference to a flowchart in a normal state in which a relative positional deviation does not occur between the spot of the diffracted light L imaged on the linear sensor 55 and the linear sensor 55.

In step 101 (ST101), the position (peak pixel position) of the pixel 56 that outputs the peak value of the signal strength is detected based on the signal output from the linear sensor 55. This peak pixel position corresponds to each light receiving position of the two or more diffracted lights received by the sensor.

In the present embodiment, the peak pixel position of the +1st-order diffracted light L1 and the peak pixel position of the -1st-order diffracted light L2 are detected. In this embodiment, the pixel number PixN is detected as it is as the peak pixel position. Hereinafter, the peak pixel positions of the ± 1st-order diffracted lights L1 and L2 are referred to as PixN1 and PixN2, respectively.

In step 102 (ST102), the difference Dpix between the two peak pixel positions is calculated by the following formula.
Dpix = PixN2-PixN1

The difference Dpix is calculated by, for example, always subtracting a small value pixel number from a large value pixel number. Alternatively, the absolute value of the difference between the two pixel numbers may be calculated as the difference Dpix (see FIG. 7 of the third embodiment).

In step 103 (ST103), the position of the object to be measured O (referred to as the distance Dist here) is calculated based on the difference Dpix. As described above, the position of the spot on the linear sensor 55 corresponds to the wavelength of the measurement light M. Therefore, the difference Dpix between the peak pixel positions PixN1 and PixN2 of each of the ± primary diffracted lights L1 and L2 is also a parameter corresponding to the wavelength of the measurement light M. As a result, the distance Dist can be calculated based on the difference Dpix.

As shown in FIG. 4, in the present embodiment, the distance Dist is calculated from the difference Dpix by using the calibration table. The calibration table is created in advance by operating the chromatic sensor 100 while adjusting the distance Dist, and is stored in the memory or the like of the control unit 60. The method and timing of creating the calibration table are not limited.

Further, the calculation of the distance Dist is not limited to the method in which the calibration table is used. For example, a predetermined calculation formula may be stored in a memory or the like, and the calculation from the difference Dpix to the distance Dist may be executed using the calculation formula. Alternatively, the wavelength of the measurement light M may be calculated from the difference Dpix. Then, the distance Dist may be calculated from the wavelength by a calibration table, calculation, or the like.

A case where a relative positional deviation occurs between the spot of the diffracted light L imaged on the linear sensor 55 and the linear sensor 55 will be described. For example, the position where the diffraction grating 52 or the linear sensor 55 is arranged may be displaced due to environmental changes such as temperature and humidity, a condition during transportation of the chromatic sensor, or long-term use. In this case, a relative misalignment occurs between the spot on the linear sensor 55 and the linear sensor 55.

When the method for measuring the distance Dist according to the present invention is executed when the misalignment occurs, referring to the flowchart with the misalignment in FIG. 4, first, in step 101 (ST101), each of the ± primary diffracted lights L1 And the peak pixel positions of L2, PixN1'and PixN2', are detected. Since the misalignment has occurred, both peak pixel positions are detected with a misalignment of ΔPix as shown in the following equation.
PixN1'= PixN1 + ΔPix
PixN2'= PixN2 + ΔPix

However, in this measurement method, since the difference Dpix'of the two peak pixel positions is calculated in step 102 (ST102), the influence of the misalignment is canceled as shown in the following equation.
Dpix'= PixN2'-PixN1'
= (PixN2 + ΔPix)-(PixN1 + ΔPix)
= PixN2-PixN1
= Dpix

Therefore, in step 103 (ST103), the distance Dist when the positional deviation does not occur is appropriately calculated. That is, in this measurement method, the relative positional deviation between the spot on the linear sensor 55 and the linear sensor 55 does not affect the calculation of the distance Dist.

FIG. 5 is a diagram for explaining a configuration of a spectroscope of a chromatic sensor given as a comparative example and a measurement method using the spectroscope. As shown in FIG. 5A, in this chromatic sensor 900, only the + 1st-order diffracted light L1 of the plurality of diffracted lights L of the measurement light M is imaged on the linear sensor 901.

As shown in FIG. 5B, in step 901 (ST901), the peak pixel position PixN1 of the +1st order diffracted light L1 is detected. Further, in step 902 (ST902), the distance Dist is calculated based on the detected PixN1 by the calibration table.

In this chromatic sensor 900, when a relative misalignment between the spot on the linear sensor 901 and the linear sensor 901 occurs, PixN1'(= PixN1 + ΔPix) deviated by the misalignment ΔPix is calculated as the peak pixel position. .. Then, in step 902 (ST902), the distance Dist'is calculated based on the PixN1'. As a result, the calculated distance will deviate. That is, the amount of deviation of the peak pixel position appears as a change in the measurement result of the distance, so that the measurement accuracy deteriorates.

On the other hand, in the chromatic sensor 100 according to the present embodiment, the object to be measured O is based on the difference between the peak pixel positions PixN1 and PixN2 of the ± primary diffracted lights L1 and L2 received by the linear sensor 55. The position of is calculated. Therefore, the relative positional deviation between the spot on the linear sensor 55 and the linear sensor 55 can be absorbed. As a result, it is possible to calculate the position of the object to be measured O with high accuracy based on the wavelength of the measurement light M reflected by the object to be measured O at the in-focus position P. In addition, it is possible to realize a chromatic sensor 100 that is robust and highly accurate in response to changes in the environment.

<Second embodiment>
The chromatic sensor according to the second embodiment of the present invention will be described. In the following description, the description of the parts similar to the configuration and operation in the chromatic sensor 200 described in the above embodiment will be omitted or simplified.

FIG. 6 is a diagram for explaining the configuration of the spectroscope of the chromatic sensor according to the present embodiment and the measurement method using the spectroscope. As shown in FIG. 6A, in the chromatic sensor 200 according to the present embodiment, of the plurality of diffracted lights L of the measurement light M, the +1st order diffracted light L1 and the 0th order diffracted light L0 are connected on the linear sensor 255. Be imaged.

As shown in FIG. 6B, the control unit detects the peak pixel position PixN1 of the +1st-order diffracted light L1 and the peak pixel position PixN0 of the 0th-order diffracted light L0 in step 201 (ST201). As for the plurality of diffracted lights L, in general, the diffracted light L having a lower order has a stronger light intensity. In consideration of this, the peak value according to the order can be appropriately detected, and the peak pixel positions PixN1 and PixN0 of the + 1st and 0th order diffracted lights L1 and L0 can be detected.

In step 202 (ST202), the difference Dpix (= PixN0-PixN1) between the two peak pixel positions is calculated, and in step 203 (ST203), the distance Dist is calculated based on the difference Dpix.

When a misalignment occurs in the chromatic sensor 200, the misalignment ΔPix is canceled when the difference Dpix'is calculated in step 202 (ST202) as shown in the following equation.
Dpix'= PixN0'-PixN1'
= (PixN0 + ΔPix)-(PixN1 + ΔPix)
= PixN0-PixN1
= Dpix

Therefore, in step 203 (ST203), the distance Dist can be calculated with high accuracy without being affected by the relative positional deviation between the spot on the linear sensor 255 and the linear sensor 255. The same effect can be obtained even if the -1st order diffracted light L2 is used instead of the +1st order diffracted light L1.

In the chromatic sensor 200 according to the present embodiment, as shown in FIG. 6A, the size of the linear sensor 255 can be reduced, so that the device can be miniaturized.

<Third embodiment>

FIG. 7 is a diagram for explaining a configuration of a spectroscope of a chromatic sensor according to a third embodiment of the present invention and a measurement method using the spectroscope. As shown in FIG. 7A, in the chromatic sensor 300 according to the present embodiment, among the plurality of diffracted lights L of the measurement light M, the + 1st, 0th, and -1st order diffracted lights L1, L0, and L2 are , Is imaged on the linear sensor 355.

In the control unit, as shown in FIG. 7B, in step 301 (ST301), the peak pixel position PixN1 of the +1st-order diffracted light L1, the peak pixel position PixN0 of the 0th-order diffracted light L0, and the -1st-order diffraction. The peak pixel position PixN2 of the light L2 is detected.

In step 302 (ST302), the difference Dpix1 between the peak pixel positions PixN1 and PixN0 and the difference Dpix2 between the peak pixel positions PixN2 and PixN0 are calculated as shown in the following equation.
Dpix1 = | PixN1-PixN0 |
Dpix2 = | PixN2-PixN0 |

Further, as shown in the following formula, the sum Dpix of the difference Dpix1 and the difference Dpix2 is calculated.
Dpix = Dpix1 + Dpix2

When Dpix1 and Dpix2 are calculated, the absolute value of (PixN1-PixN0) and the absolute value of (PixN2-PixN0) may not be calculated. In this case, when Dpix is calculated, the absolute value of Dpix1 and the absolute value of Dpix2 are calculated, and they are added together.

In step 303 (ST303), the distance Dist is calculated based on the sum Dpix calculated above. Note that the sum Dpix, which is the sum of the difference Dpix1 between the peak pixel positions PixN1 and PixN0 and the difference DPix2 between the peak pixel positions PixN2 and PixN0, is a parameter calculated based on the difference between the light receiving positions of the two or more diffracted lights. It becomes.

When a misalignment occurs in the chromatic sensor 300, the misalignment ΔPix is canceled when the difference Dpix1'and the difference Dpix2' are calculated in step 302 (ST302) as shown in the following equation.
Dpix1'= | PixN1'-PixN0'|
= | (PixN1 + ΔPix)-(PixN0 + ΔPix) |
= | PixN1-PixN0 |
= Dpix1
Dpix2'= | PixN2'-PixN0'|
= | (PixN2 + ΔPix)-(PixN0 + ΔPix) |
= | PixN2-PixN0 |
= Dpix2

Therefore, in step 303 (ST303), the distance Dist can be calculated with high accuracy without being affected by the relative positional deviation between the spot on the linear sensor 355 and the linear sensor 355. Further, the measurement accuracy can be improved by using the sum Dpix of the difference Dpix1 between the peak pixel positions PixN1 and PixN0 and the difference DPix2 between the peak pixel positions PixN2 and PixN0 with reference to the 0th-order diffracted light L0.

<Other Embodiments>
The present invention is not limited to the embodiments described above, and various other embodiments can be realized.

In each of the above embodiments, the + 1, 0, and -1 diffracted lights of the plurality of diffracted lights were appropriately used. Since these diffracted lights have high light intensity, it is possible to calculate the position of the object with high accuracy. However, diffracted light of order other than +1st order, 0th order, and -1st order may be used, and the position of the object to be measured may be calculated based on the difference between these light receiving positions.

In the measuring method according to the present invention, the position of the object to be measured is detected based on the difference between the light receiving positions of the two or more diffracted lights. Therefore, it is also possible to use a diffraction grating that causes two ± nth-order diffracted lights to appear at positions that are not substantially symmetrical with respect to the 0th-order diffracted light. Further, as long as two or more diffracted lights are received by the linear sensor, a member such as a diffraction grating may be arranged obliquely with respect to the optical axis of the measurement light emitted into the spectroscope.

Further, in the above, white light was used as the light containing a plurality of visible lights. The present invention is not limited to this, and the present invention is applicable even when other light in a wide band is used. That is, invisible light such as ultraviolet rays and infrared rays may be emitted as a plurality of lights having different wavelengths. For example, an LED or the like that emits ultraviolet rays can be used as a light source unit according to the present invention.

It is also possible to combine at least two feature parts among the feature parts of each of the above-described embodiments. Further, the various effects described above are merely examples and are not limited, and other effects may be exhibited.

λ ... Wavelength L ... Diffractive light O ... Object P ... Focusing position 10 ... Optical head 20 ... Controller 30 ... Optical fiber section 40 ... Light source section 50 ... Spectrometer 52 ... Diffraction grating 55, 255, 355 ... Linear sensor 60 … Signal processing / control unit 100, 200, 300… Chromatic cofocal sensor

Claims (3)

A light source unit that emits multiple lights of different wavelengths,
An optical head having an objective lens that converges each of the plurality of lights to different focusing positions, and selecting the light reflected by the object to be measured at the focusing position among the plurality of lights as the measurement light. When,
A spectroscope having a diffraction grating that divides the selected measurement light into a plurality of diffracted lights, and a sensor that receives at least two or more diffracted lights among the plurality of diffracted lights.
It is provided with a signal processing / control unit that calculates the position of the object to be measured based on the difference between the light receiving positions of the two or more diffracted lights received by the sensor.
The two or more diffracted lights include at least two of the +1st order, 0th order, and -1st order diffracted lights.
The signal processing / control unit is a chromatic confocal sensor that calculates the position of the object to be measured based on the difference in the light receiving positions of the +1st order and the -1st order diffracted light. The chromatic confocal sensor according to claim 1 .
The light source unit is a chromatic confocal sensor that emits white light including the plurality of lights. An emission step that emits multiple lights, each with a different wavelength,
A convergence step of converging each of the plurality of lights to different focusing positions.
A selection step of selecting the light reflected by the object to be measured at the in-focus position among the plurality of lights as the measurement light, and
A light receiving step that divides the selected measurement light into a plurality of diffracted lights and receives at least two or more diffracted lights among the plurality of diffracted lights by a sensor.
It is provided with a calculation step of calculating the position of the object to be measured based on the difference between the light receiving positions of the two or more diffracted lights received by the sensor.
In the light receiving step, the two or more diffracted lights include at least two of the +1st order, 0th order, and -1st order diffracted lights.
The calculation step is a measurement method for calculating the position of the object to be measured based on the difference between the light receiving positions of the +1st order and the -1st order diffracted light.

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