JP2020180980A - Optical measuring device - Google Patents

Abstract

To provide an optical measuring device based on the white light confocal principle that can detect an abnormality in a received light waveform.SOLUTION: An optical measuring device 1 according to a certain aspect of the present invention comprises: a light source 10 that generates irradiation light having a plurality of waveform components; a sensor head 30 that generates an axial chromatic aberration for the irradiation light from the light source 10, and receives reflected light from a measurement object 2 at least a part of which is arranged on an extension line of an optical axis; a light receiving unit 40 that separates the reflected light received by the sensor head 30 into the waveform components and receives light of the waveform components; a light guide unit 20 that optically connects the light source 10, the light receiving unit 40, and the sensor head 30; and a processing unit 50 that calculates a distance from an optical system to the measurement object based on a light reception amount of the waveform components in the light receiving unit 40. The processing unit 50 compares the light reception amount of each of the plurality of waveform components in a received light waveform with a reference value of the received light amount, and based on a result of the comparison, determines whether the distance to the measurement object can be normally measured.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an optical measuring device capable of measuring the surface shape and the like of a measurement object by a white confocal method.

A white confocal optical measuring device is known as a device for inspecting the surface shape of an object to be measured. This type of optical measuring device uses a light source that generates irradiation light having a plurality of wavelength components, an optical system that causes axial chromatic aberration with respect to the irradiation light from the light source, and reflected light received by the optical system. It includes a light receiving unit that separates into wavelength components and receives light of each wavelength component, and a light guide unit that optically connects the light source, the light receiving unit, and the optical system. For example, Japanese Patent Application Laid-Open No. 2012-208102 (Patent Document 1) discloses a confocal measuring device that measures the displacement of a measurement object in a non-contact manner using a confocal optical system.

Japanese Unexamined Patent Publication No. 2012-208102

In a displacement sensor based on the white confocal principle, a change in the received light waveform due to an increase in return light or the like causes an influence on the measurement. Conventionally, such a change in the received light waveform could not be detected, and the user could not notice that the received light waveform was abnormal. The increase in the return light causes a decrease in the measurement accuracy of the sensor, but the user may continue to use the sensor without knowing it.

An object of the present invention is to provide an optical measuring device based on a white confocal principle capable of detecting an abnormality in a received light waveform.

An optical measuring device according to a certain aspect of the present invention causes an axial chromatic aberration with respect to a light source that generates irradiation light having a plurality of wavelength components and irradiation light from the light source, and at least one of them on an extension line of the optical axis. An optical system that receives the reflected light from the object to be measured in which the unit is arranged, a light receiving unit that separates the reflected light received by the optical system into each wavelength component and receives the light of each wavelength component, and a light receiving unit. It is provided with a processing unit that calculates the distance from the optical system to the object to be measured based on the amount of received light of each wavelength component in the above. The processing unit compares the received light amount of each of the plurality of wavelength components in the received light waveform with the reference value of the received light amount, and the amount of change of the received light amount with respect to the reference value is equal to or greater than a predetermined threshold value for any of the plurality of wavelength components. If, an abnormality in the received light waveform is detected.

According to the above configuration, it is possible to provide an optical measuring device based on the white confocal principle that can detect an abnormality in the received light waveform. The "distance from the optical system to the measurement target" is the distance from the optical system to the measurement target position on the measurement target, and is not limited to the shortest distance from the optical system to the measurement target. The measurement target position is a position on the measurement target to which the irradiation light from the light source is irradiated. The measurement target position is not limited to one.

Preferably, the processing unit measures the displacement of the object to be measured based on the peak wavelength in the received light waveform when the amount of change in the received light amount in at least one of the plurality of wavelength components is less than the threshold value.

According to the above configuration, even when one of the selected plurality of wavelengths matches the measurement wavelength, the abnormal waveform can be detected based on the amount of light received at the other wavelengths.

Preferably, the plurality of wavelength components comprises five wavelengths.
According to the above configuration, for example, the object to be measured has a configuration in which a space is provided between two transparent bodies (glass or the like) by a spacer or the like, and four of the five selected wavelengths are measured. Even when it matches the wavelength, the abnormal waveform can be detected based on the amount of light received at the remaining one wavelength.

Preferably, the threshold is set for each wavelength based on the spectrum of the light source.
According to the above configuration, the abnormal waveform can be detected more accurately by setting the threshold value for each wavelength.

An optical measuring device according to another aspect of the present invention causes an axial chromatic aberration with respect to a light source that generates irradiation light having a plurality of wavelength components and irradiation light from the light source, and at least the optical measuring device thereof is on an extension of the optical axis. An optical system that receives reflected light from a measurement object on which a part is arranged, a light receiving unit that separates the reflected light received by the optical system into each wavelength component and receives the light of each wavelength component, and a light receiving unit. The unit includes a processing unit that calculates the distance from the optical system to the object to be measured based on the amount of light received by each wavelength component. The processing unit compares the received light amount of the wavelength component outside the wavelength region corresponding to the measurement range of the displacement of the measurement object with the reference value of the received light amount, and the amount of change of the received light amount with respect to the reference value is predetermined. If it is equal to or higher than the threshold value, an abnormality in the light receiving waveform indicating the amount of light received is detected.

According to the above configuration, the received light waveform can be monitored while reducing the influence on the measurement of the displacement of the object.

Preferably, when an abnormality is detected in any of the above optical measuring devices, the processing unit notifies the abnormality.

According to the above configuration, the user can notice that the received light waveform of the optical measuring device is abnormal. As a result, the user can take appropriate measures to eliminate the cause of the abnormality. Therefore, the measurement accuracy of the displacement of the object can be maintained high.

According to the present invention, it is possible to detect an abnormality in the received light waveform in an optical measuring device based on the principle of white confocal.

It is a figure for demonstrating the principle of the distance measurement by the white confocal method. It is a schematic diagram for demonstrating the structure of the light guide part of the optical measuring apparatus according to this Embodiment. It is a schematic diagram which shows an example of the apparatus configuration of the optical measuring apparatus according to this embodiment. It is a schematic diagram for demonstrating the reflection of a part of the irradiation light in the middle of a light guide part. It is a figure for demonstrating the problem in the case where a part of irradiation light is reflected in the middle of a light guide part. It is a figure for demonstrating the processing of the received light signal in the optical measuring apparatus which concerns on this embodiment. It is a schematic waveform diagram for demonstrating the determination of abnormality of the optical measuring apparatus by 1st Embodiment. It is a figure explaining the measurement of the displacement of a plurality of surfaces of a measurement object by the optical measuring apparatus which concerns on this embodiment. It is a figure which shows typically the change of the received light amount of the background component when a part of the irradiation light is reflected and returned in the middle of a light guide part. It is a figure which showed the example of the relationship between a monitoring wavelength and a threshold value. It is a flowchart for demonstrating the detection process of the abnormal waveform which concerns on 1st Embodiment. It is a figure explaining the spectrum of the light source for demonstrating the detection of the abnormal waveform which concerns on 2nd Embodiment. It is a flowchart for demonstrating the detection process of the abnormal waveform which concerns on 2nd Embodiment.

Embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated.

<A. Overview>
First, the problems solved by the optical measuring device according to the present embodiment and the configuration for realizing the problems will be outlined.

FIG. 1 is a diagram for explaining the principle of distance measurement by the white confocal method. With reference to FIG. 1, the optical measuring device 1 includes a light source 10, a light guide unit 20, a sensor head 30, a light receiving unit 40, and a processing unit 50. The sensor head 30 includes a chromatic aberration unit 32 and an objective lens 34, and a light receiving unit 40 includes a spectroscope 42 and a detector 44.

The irradiation light having a predetermined wavelength spread generated by the light source 10 propagates through the light guide unit 20 and reaches the sensor head 30. In the sensor head 30, the irradiation light from the light source 10 is focused by the objective lens 34 and irradiated to the measurement object 2. Since axial chromatic aberration occurs in the irradiation light by passing through the chromatic aberration unit 32, the focal position of the irradiation light emitted from the objective lens 34 differs for each wavelength. Of the wavelengths reflected on the surface of the object to be measured 2, only the light having the wavelength focused on the object 2 to be measured re-enters only the confocal fiber of the light guide portion 20 of the sensor head 30. Become. Hereinafter, for convenience of explanation, a state in which light having a wavelength focused on the measurement object 2 is detected as measurement light is also referred to as “reflecting only a specific wavelength”.

The reflected light re-entered on the sensor head 30 propagates through the light guide unit 20 and is incident on the light receiving unit 40. In the light receiving unit 40, the reflected light incident on the spectroscope 42 is separated into each wavelength component, and the intensity of each wavelength component is detected by the detector 44. The processing unit 50 calculates the distance (displacement) from the sensor head 30 to the measurement object 2 based on the detection result of the detector 44.

In the example shown in FIG. 1, for example, the irradiation light including a plurality of wavelengths λ1, λ2, λ3 is wavelength-dispersed and images are imaged at different positions (focus position 1, focal position 2, focal position 3) on the optical axis AX. Will be drawn. Since the surface of the object to be measured 2 coincides with the focal position 2 on the optical axis AX, only the component having the wavelength λ2 of the irradiation light is reflected. The light receiving unit 40 detects the component of the wavelength λ2 and calculates that the distance from the sensor head 30 to the measurement object 2 is a distance corresponding to the focal position of the wavelength λ2.

Of the plurality of light receiving elements constituting the detector 44 of the light receiving unit 40, the light receiving element that receives the reflected light changes according to the shape of the surface of the measurement object 2 with respect to the sensor head 30, and therefore the detector 44. The distance change (displacement) with respect to the measurement object 2 can be measured from the detection results (pixel information) by the plurality of light receiving elements. As a result, the shape of the surface of the object to be measured 2 can be measured by the optical measuring device 1. The distance from the sensor head 30 to the measurement target object 2 is the distance from the sensor head 30 to the measurement target position on the measurement target object 2, and is not limited to the shortest distance from the sensor head 30 to the measurement target object 2. The measurement target position is a position on the measurement target 2 to which the irradiation light from the light source 10 is irradiated. The measurement target position is not limited to one. For example, two different measurement target positions may be selected along the optical axis direction of the sensor head 30. By calculating the distance from the sensor head 30 to each measurement target position and calculating the difference between the two distances, for example, the thickness of the measurement target object 2 can be calculated.

FIG. 2 schematically shows the configuration of the light guide unit of the optical measuring device 1 according to the present embodiment. As shown in FIG. 2A, the optical measuring device 1 has an input side cable 21 optically connected to the light source 10 and an output side optically connected to the light receiving unit 40 as the light guide unit 20. The cable 22 includes a head-side cable 24 that is optically connected to the sensor head 30. Each end of the input side cable 21 and the output side cable 22 and the end of the head side cable 24 are optically coupled via a coupler 23 having a combine / demultiplexing structure. The coupler 23 is a 2 × 1 star coupler (2 inputs, 1 output / 1 input, 2 outputs) corresponding to a Y-branch coupler, and transmits the light incident from the input side cable 21 to the head side cable 24 and also transmits the head side cable. The light incident from the 24 is divided and transmitted to the input side cable 21 and the output side cable 22, respectively.

The input side cable 21, the output side cable 22, and the head side cable 24 are all optical fibers having a single core 202, and the cross-sectional structure thereof is a clad 204 and a coating 206 from the core 202 to the outer periphery. And the exterior 208 are sequentially provided around the core 202. As shown in FIG. 2B, the optical measuring device 1 according to the present embodiment may employ an optical fiber having a plurality of cores as the light guide unit 20.

<B. Device configuration>
FIG. 3 is a schematic view showing an example of the device configuration of the optical measuring device 1 according to the present embodiment. The optical measuring device 1 according to the present embodiment with reference to FIG. 3 includes a light source 10, a light guide unit 20, a sensor head 30, a light receiving unit 40, and a processing unit 50.

The light source 10 generates irradiation light having a plurality of wavelength components, and is typically realized by using a white LED (Light Emitting Diode). Any light source may be used as long as the displacement width of the focal position caused by the axial chromatic aberration can generate irradiation light having a wavelength range sufficient to cover the required measurement range.

The sensor head 30 includes a chromatic aberration unit 32 and an objective lens 34, causes axial chromatic aberration with respect to the irradiation light from the light source 10, and is a measurement object in which at least a part thereof is arranged on an extension line of the optical axis AX. It corresponds to an optical system that receives the reflected light from 2.

The light receiving unit 40 includes a spectroscope 42 that separates the reflected light received by the sensor head 30 that is an optical system into each wavelength component, and a plurality of light receiving elements arranged corresponding to the spectral directions by the spectroscope 42. Includes vessel 44. A diffraction grating is typically used as the spectroscope 42, but any other device may be used. The detector 44 may use a line sensor (one-dimensional sensor) in which a plurality of light receiving elements are one-dimensionally arranged corresponding to the spectral direction of the spectroscope 42, or the plurality of light receiving elements are two-dimensionally arranged on the detection surface. An arranged image sensor (two-dimensional sensor) may be used.

In addition to the spectroscope 42 and the detector 44, the light receiving unit 40 outputs the collimating lens 41 that parallelizes the reflected light emitted from the output side cable 22 and the detection result of the detector 44 to the processing unit 50. The reading circuit 45 of the above is included. Further, if necessary, a reduction optical system 43 that adjusts the spot diameter of the reflected light for each wavelength separated by the spectroscope 42 may be provided.

The processing unit 50 calculates the distance from the sensor head 30 to the measurement object 2 based on the respective detection values of the plurality of light receiving elements of the light receiving unit 40. The relational expression between the pixel, the wavelength, and the distance value is preset (for example, it is stored non-volatilely inside the processing unit 50 at the time of product shipment). Therefore, the processing unit 50 can calculate the displacement from the light receiving waveform (pixel information) output by the light receiving unit 40.

FIG. 3 shows an example in which a plurality of cables are connected in series to form a head-side cable in order to improve usability. That is, as the head side cable, three cables 241,243,245 are adopted. The cable 241 and the cable 243 are optically connected via the connector 242, and the cable 243 and the cable 245 are optically connected via the connector 244.

The light guide unit 20 includes a combine / demultiplexing unit (coupler) 23 for optically coupling the input side cable 21, the output side cable 22, and the head side cable. Since the functions of the combine / demultiplexing unit 23 have been described with reference to FIG. 2, detailed description will not be repeated.

As described above, in the optical measuring device 1 according to the present embodiment, by adopting the coupler as the combine / demultiplexing structure, the light can be separated in the light guide unit 20 and propagates in each of the plurality of cores. The reflected light (measurement light) from the measurement object 2 can be received by a single detector 44.

<C. Problem of reflected light>
In principle, on the optical axis AX, only the wavelength component that focuses at the position of the surface of the measurement object 2 is reflected and incident on the light receiving unit 40. However, in the middle of the light guide unit 20 (that is, the optical path of the irradiation light from the light source 10 to the sensor head), a part of the irradiation light may be reflected and the reflected light may be incident on the light receiving unit 40.

FIG. 4 is a schematic diagram for explaining the reflection of a part of the irradiation light in the middle of the light guide unit 20. As shown in FIG. 4, for example, a part of the irradiation light is reflected at the combine / demultiplexing portion 23 (coupler 231,232), the connector 242, the connector 244, or the connection portion between the sensor head 30 and the cable 245. Can be done. Further, an increase or decrease in the power of the light source 10 causes an abnormality in the amount of return light.

For example, if the combine / demultiplexing portion 23 is defective, or if the connectors 242 and 244 are scratched or dirty, it is possible that a part of the irradiation light is reflected and returned. Further, due to the long distance of the optical fiber included in the cable, the irradiation light may be scattered inside the optical fiber. Further, a part of the irradiation light can be reflected by scratches or stains on the end face of the optical fiber.

FIG. 5 is a diagram for explaining a problem when a part of the irradiation light is reflected in the middle of the light guide unit 20. With reference to FIG. 5, the processing unit 50 identifies the peak position of the light receiving intensity based on the light receiving waveform (profile of the light receiving intensity). The processing unit 50 identifies the main component of the wavelength contained in the reflected light from the wavelength corresponding to the peak position, and based on the specified main component wavelength (for example, wavelength λ2), from the sensor head 30 to the measurement object 2. Calculate the distance (displacement) of.

When the optical measuring device 1 is normal, the noise component (background noise) is sufficiently small. However, when a part of the irradiation light is reflected by the light guide unit 20 and incident on the light receiving unit 40, the light receiving intensity of the noise component, that is, the wavelength component other than the wavelength λ2 becomes large.

FIG. 6 is a diagram for explaining the processing of the received light signal in the optical measuring device 1 according to the present embodiment. FIG. 6A is a waveform diagram illustrating a light receiving waveform obtained in a normal state of the optical measuring device 1. FIG. 6B is a waveform diagram illustrating a light receiving waveform obtained when the optical measuring device 1 is abnormal.

As shown in FIGS. 6 (A) and 6 (B), the optical measuring device 1 according to the present embodiment has a waveform (measured waveform) generated by the difference between the received light waveform and the return light component waveform. Based on this, the main component wavelength is specified. The return light component waveform is acquired prior to the measurement of displacement, for example, and is stored inside the optical measuring device 1.

When the optical measuring device 1 is normal, the difference between the return light component included in the received light waveform and the return light component in the waveform acquired in advance is small. In the measured waveform, the return light component is almost canceled, so that the S / N ratio is high. Therefore, the main component wavelength can be specified with high accuracy.

On the other hand, as shown in FIG. 6B, when the return light component included in the received light waveform is large, even if the difference between the received light waveform and the pre-stored return light component waveform is generated, it is included in the received light waveform. The return light component cannot be completely offset. Therefore, the S / N ratio of the measured waveform is low. As the S / N ratio decreases, the peak wavelength detection accuracy decreases, so that the displacement measurement accuracy decreases.

In the present embodiment, the processing unit 50 monitors the amount of light received at a specific wavelength. When the light receiving amount at that wavelength changes by a threshold value or more with respect to the normal light receiving amount, the processing unit 50 detects an abnormality in the light receiving waveform. Further, the processing unit 50 notifies the abnormality. The user can remove the cause of the abnormal waveform by cleaning the connectors 242 and 244, replacing the light guide unit 20, and the like. Further, when the increase in the return light is due to the extension of the optical fiber, the cause of the abnormal waveform can be eliminated by storing the value of the return light component in the optical measuring device 1 again. .. Therefore, the measurement accuracy of the displacement of the object can be maintained high. The details of the present embodiment will be described below.

<D. First Embodiment>
FIG. 7 is a schematic waveform diagram for explaining the determination of the abnormality of the optical measuring device 1 according to the first embodiment. With reference to FIGS. 3 and 7, the light receiving amounts I1, I2, I3, I4, I5 at each of the wavelengths λ1, λ2, λ3, λ4, λ5 are measured by the light receiving unit 40. The processing unit 50 compares the light receiving amount at each wavelength with the reference value (normal light receiving amount) corresponding to the wavelength. For example, the reference value is initially set at the factory. When the sensor head is inserted or removed at the site, the reference value can be reset by, for example, the user operating an operation button (not shown) of the optical measuring device 1.

The processing unit 50 determines whether or not the difference between the light receiving amount and the reference value exceeds the threshold value for each wavelength. When the difference between the light receiving amount and the reference value exceeds the threshold value at all the wavelengths λ1, λ2, λ3, λ4, λ5, the processing unit 50 determines that an abnormality has occurred in the optical measuring device 1. The reference value and the threshold value are set for each wavelength and are stored inside the processing unit 50.

The number of wavelengths at which the amount of received light and the reference value are compared may be larger than the number of surfaces of the measurement object 2 that requires measurement of displacement. The optical measuring device 1 may detect a plurality of surfaces, but it is a case where the measuring object 2 is a transparent body. In this case, the peak of the received light waveform appears at a number of wavelengths corresponding to the number of the front surface and the back surface of the transparent object 2 to be measured. The number of thresholds is determined according to the peak of the received light waveform. The minimum number of surfaces for which displacement is to be measured is 1. Even when one of the plurality of selected wavelengths matches the measurement wavelength, the abnormal waveform can be detected based on the amount of light received at the other wavelengths.

The reason for using the five wavelengths in the first embodiment will be described below. FIG. 8 is a diagram illustrating measurement of displacement of a plurality of surfaces of the object to be measured 2 by the optical measuring device 1 according to the present embodiment.

As shown in FIG. 8, for example, the measurement object 2 has a configuration in which a space is provided between two transparent bodies (glass or the like) by a spacer or the like. The object 2 to be measured has four surfaces 2a, 2b, 2c, 2d with different displacements, which are two surfaces (2a, 2c) of the transparent body and two back surfaces (2b, 2d) of the transparent body. is there. Therefore, the optical measuring device 1 can measure the displacements of the two front surfaces and the two back surfaces of the transparent body. The wavelength for detecting the abnormal waveform can be arbitrarily selected. However, when four wavelengths are selected for detecting an abnormal waveform, the wavelengths that are in focus on the two front surfaces and the two back surfaces of the measurement object 2 (two transparent objects) and the four selected wavelengths are selected. It is necessary to consider the possibility of matching the wavelength. Therefore, the number of faces detected and the number of wavelengths selected must be different.

In the example shown in FIG. 8, the focal position of the component of wavelength λ5 in the irradiation light is different from any of the positions of the surfaces 2a, 2b, 2c, and 2d. Therefore, the abnormality of the optical measuring device 1 can be detected by comparing the component of the wavelength λ5 in the received light waveform with the reference value.

The setting of each wavelength and the setting of the threshold value may be set by the user based on the result of teaching. The wavelength and the threshold value can be set according to the emission spectrum of the light source 10. The setting and the threshold value of each wavelength may be set in advance at the time of shipment from the factory, for example.

FIG. 9 is a diagram schematically showing a change in the amount of received light of the background component when a part of the irradiation light is reflected and returned in the middle of the light guide unit 20. With reference to FIG. 9, when a part of the irradiation light is reflected and returned in the middle of the light guide unit 20, the amount of change in the return light component depends on the wavelength. For example, at a wavelength close to the peak of the return light component, the amount of change in the return light component tends to be large, so the threshold value is set relatively large. On the contrary, at a wavelength shorter or longer than the peak wavelength of the return light component, the amount of change of the return light component tends to be small, so the threshold value at that wavelength is set relatively small. As a result, the abnormal waveform can be detected more accurately.

FIG. 10 is a diagram showing an example of the relationship between the monitoring wavelength and the threshold value. As shown in FIG. 10, threshold values Th1, Th2, ..., Thn are set for each of n wavelengths λ1, λ2, ..., λn (n is an integer of 2 or more). Note that FIG. 8 shows an example of n = 5. The relationship shown in FIG. 10 is stored inside the processing unit 50.

FIG. 11 is a flowchart for explaining the abnormal waveform detection process according to the first embodiment. When the processing is started with reference to FIGS. 3 and 11, in step S1, the processing unit 50 uses the light receiving amount (that is, the wavelength component) at each of the wavelengths λ1, λ2, ..., λn as a reference value. Compare. In step S2, the processing unit 50 determines whether or not the amount of change in the amount of received light is equal to or greater than the threshold value at all wavelengths.

When the amount of change in the amount of received light with respect to the reference value is equal to or greater than the threshold value at all wavelengths (YES in step S2), the processing unit 50 detects an abnormal waveform in step S3. In this case, in step S4, the processing unit 50 executes a notification process for notifying the user that an abnormal waveform has been detected. The method of notification is not particularly limited, and for example, a well-known method using sound, light, or the like can be adopted.

On the other hand, when the amount of change in the received light amount with respect to the reference value is less than the threshold value at at least one wavelength (NO in step S2), the processing unit 50 executes the displacement measurement process based on the received light waveform in step S5. After the displacement measurement process is completed, the process is returned to step S1.
<E. Second Embodiment>
In the second embodiment, the optical measuring device 1 detects an abnormal waveform based on the amount of change in the amount of light received at a single wavelength. Since the configuration of the optical measuring device 1 is the same as the configuration according to the first embodiment, the following description will not be repeated.

FIG. 12 is a diagram illustrating the spectrum of the light source 10 for explaining the detection of the abnormal waveform according to the second embodiment. With reference to FIG. 12, the wavelength region 60 is a wavelength region used for displacement measurement, and is referred to as a “measurement range” here. In the second embodiment, the anomalous waveform is detected using one wavelength selected from the wavelength region 61 or the wavelength region 62 outside the measurement range. Similar to the first embodiment, an abnormal waveform is detected when the amount of change in the amount of received light (wavelength component) is equal to or greater than the threshold value at the selected wavelength. Since the amount of light received at one wavelength selected from the wavelength region outside the measurement range is monitored, the influence on the measurement of the displacement of the object can be reduced.

FIG. 13 is a flowchart for explaining the abnormal waveform detection process according to the second embodiment. With reference to FIGS. 11 and 13, in the second embodiment, the processes of steps S11 and S12 are executed instead of steps S1 and S2. In step S11, the processing unit 50 compares the amount of light received at the wavelength λo outside the wavelength region 60 with the reference value. The wavelength λo is preset. In step S12, the processing unit 50 determines whether or not the amount of change in the amount of received light is equal to or greater than the threshold value at the wavelength λo.

When the amount of change in the amount of received light with respect to the reference value is equal to or greater than the threshold value (YES in step S12), the process proceeds to step S3, and the processing unit 50 detects an abnormal waveform. In step S4, the processing unit 50 executes a notification process for notifying the user that an abnormal waveform has been detected. On the other hand, when the amount of change in the amount of received light with respect to the reference value is less than the threshold value (NO in step S12), the process proceeds to step S5. In this case, the processing unit 50 executes the displacement measurement process. After the displacement measurement process is completed, the process is returned to step S11.

In the second embodiment, it is determined whether or not the received light waveform is abnormal based on the amount of change in the received light amount at a wavelength outside the measurement range. Therefore, an abnormal waveform may be detected based on the amount of change in the amount of light received at each of a plurality of wavelengths selected from the wavelength region outside the measurement range.

<F. Advantages>
As described above, the optical measuring device 1 according to the present embodiment can detect an abnormality in the received light waveform. Further, the user can be made aware of the abnormality of the received light waveform. When the measurement accuracy deteriorates due to the increase in the return light, an abnormality in the received light waveform is detected. Upon notification from the optical measuring device 1, the user can take appropriate measures to improve the reduced accuracy (for example, in the case of an increase in the return light due to cleaning of the connector or extension of the fiber, the value of the return light component is optically measured again. It can be stored inside the measuring device 1). Therefore, even when the accuracy of the displacement measurement in the optical measuring device is lowered, the high measurement accuracy can be achieved again.

The embodiments disclosed this time should be considered as exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Optical measuring device, 2 Measurement target, 2a, 2b, 2c, 2d surface (measurement target), 10 light source, 20 light guide, 21 input side cable, 22 output side cable, 23 coupler, 231,232 coupler ( Combined / demultiplexed structure), 24 head side cable, 30 sensor head, 32 chromatic aberration unit, 34 objective lens, 40 light source, 41 collimating lens, 42 spectroscope, 43 reduction optical system, 44 detector, 45 read circuit, 50 Processing section, 60, 61, 62 wavelength region, 202 core, 204 clad, 206 coating, 208 exterior, 241,243,245 cable, 242,244 connector, AX optical axis, I1, I2, I3, I4, I5 Amount, S1-S5, S11, S12 steps.

Claims (11)

A light source that generates irradiation light with multiple wavelength components,
An optical system that causes axial chromatic aberration with respect to the irradiation light from the light source and receives reflected light from a measurement object whose at least a part thereof is arranged on an extension line of the optical axis.
A light receiving unit that separates the reflected light received by the optical system into each wavelength component and receives the light of each wavelength component,
A processing unit that calculates the distance from the optical system to the measurement object based on the amount of light received by each wavelength component in the light receiving unit is provided.
The processing unit can compare the light receiving amount of each of the plurality of wavelength components in the light receiving waveform with the reference value of the light receiving amount, and can normally measure the distance to the measurement object based on the result of the comparison. An optical measuring device that determines whether or not. When the change amount of the received light amount in at least one of the plurality of wavelength components is less than the threshold value, the processing unit determines the displacement of the measurement object based on the peak wavelength in the received light waveform. The optical measuring device according to claim 1, wherein the optical measuring device is measured. The optical measuring device according to claim 1, wherein the plurality of wavelength components include five wavelengths. The optical measuring device according to claim 1, wherein the threshold value is determined for each wavelength based on the spectrum of the light source. A light source that generates irradiation light with multiple wavelength components,
An optical system that causes axial chromatic aberration with respect to the irradiation light from the light source and receives reflected light from a measurement object whose at least a part thereof is arranged on an extension line of the optical axis.
A light receiving unit that separates the reflected light received by the optical system into each wavelength component and receives the light of each wavelength component,
A processing unit that calculates the distance from the optical system to the measurement object based on the amount of light received by each wavelength component in the light receiving unit is provided.
The processing unit compares the light receiving amount of each of the plurality of wavelength components in the light receiving waveform with the reference value of the light receiving amount, calculates the distance to the measured object when the comparison result is normal, and performs the comparison. An optical measuring device that notifies the abnormality when the result is abnormal. The optical measuring device according to claim 5, wherein the abnormality is an abnormality related to reflection of a part of the irradiation light in the optical system. The optical system is
With the sensor head
It includes a cable connected to the sensor head and connected to the light source and the light receiving portion.
The optical measuring device according to claim 5, wherein the abnormality is an abnormality related to reflection of a part of the irradiation light at a connection portion between the sensor head and the cable. The optical system is
With the sensor head
A cable connected to the sensor head and connected to the light source and the light receiving portion,
Including the combiner provided in the cable
The optical measuring device according to claim 5, wherein the abnormality is an abnormality related to a defect in the wave junction. The optical system is
With the sensor head
A cable connected to the sensor head and connected to the light source and the light receiving portion,
Including the demultiplexing part provided in the cable
The optical measuring device according to claim 5, wherein the abnormality is an abnormality related to a defect in the demultiplexing portion. The optical system is
With multiple cables
Includes at least one connector for connecting the plurality of cables in series.
The optical measuring device according to claim 5, wherein the abnormality is an abnormality related to a defect of at least one connector or an abnormality related to the length of series connection of the plurality of cables. The optical system is
Has a cable containing optical fiber
The optical measuring device according to claim 5, wherein the abnormality is an abnormality caused by a scratch on the end face of the optical fiber or an abnormality caused by dirt on the end face of the optical fiber.

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