JP7076954B2 - Confocal displacement meter - Google Patents

Description

The present invention relates to a confocal displacement meter, and more particularly to an improvement of a confocal displacement meter that measures the displacement of a measurement object by using a confocal optical system.

The cofocal displacement meter has a cofocal principle that narrows down the light received by the reflected light from the image plane on which the image of the light source is formed, and a phenomenon of axial chromatic aberration that causes color shift in the image of the light source in the optical axis direction. It is an optical measuring device that measures the displacement of the object to be measured by using and.

The cofocal displacement meter is an optic that causes axial chromatic aberration in the pinhole emitted from the light source as a point light source and the detected light emitted through the pinhole, and converges the detected light toward the object to be measured. It is composed of a member and a spectroscope that disperses the reflected light from the object to be measured and generates a light receiving signal. As the detection light, light having a plurality of wavelengths, for example, white light is used. The pinhole passes the detection light having a wavelength reflected on the measurement object while focusing on the detection light emitted to the measurement object through the optical member.

Since the position of the image plane differs for each wavelength due to axial chromatic aberration, the displacement of the object to be measured can be obtained by specifying the wavelength of the detected light that has passed through the pinhole. The displacement is the distance in the optical axis direction from the predetermined reference position to the object to be measured, and by obtaining the displacement, the depth or height of the unevenness of the surface, the thickness of the transparent body, and the like can be measured. ..

The confocal displacement meter consists of a head unit having a confocal optical system and a control device having a light source for floodlight and a spectroscope, and the light of the light source for floodlight is transmitted via a cable made of an optical fiber. Some are transmitted to the head unit. In this type of displacement sensor, the head unit is installed near the object to be measured and is often far away from the control device.

With the conventional confocal displacement meter as described above, there is a problem that it is difficult to identify whether or not the head unit is properly installed when the head unit is installed. Even if the display unit is provided on the control device side, it is difficult for the operator during the installation work to check the display of the control device from the vicinity of the installation location of the head unit. Therefore, the operator had to move to the installation location of the control device to check the display. In addition, if the installation state of the head unit is not appropriate, the work of moving to the installation location of the head unit, adjusting the position and posture, and then moving to the installation location of the control device again to check the display must be repeated. I had to.

Further, with the conventional confocal displacement meter, there is a problem that it is difficult to identify whether or not the control device is operating normally in the vicinity of the installation location of the head unit.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a confocal displacement meter capable of improving workability when installing a head unit. In particular, it is an object of the present invention to provide a confocal displacement meter that can easily identify whether or not the head unit is properly installed when the head unit is installed. Another object of the present invention is to provide a confocal displacement meter capable of improving workability at the time of installing the head unit while suppressing the complicated configuration of the head unit. Another object of the present invention is to provide a confocal displacement meter that can easily identify whether or not the control device is operating normally in the vicinity of the installation location of the head unit.

The cofocal displacement meter according to the first aspect of the present invention is derived from a head unit having a cofocal optical system, a control device having a light projecting light source that generates light containing a plurality of wavelengths, and the light projecting light source. A confocal displacement meter including a fiber cable made of an optical fiber that transmits light to the head unit, wherein the head unit causes axial chromatic aberration in the detected light emitted through the end face of the optical fiber. At the same time, it has an optical member that converges the detected light toward the measurement object, and the control device is on the measurement object among the detection lights irradiated to the measurement object via the optical member. A spectroscope that disperses the detected light that has passed through the end face of the optical fiber by being reflected while focusing on the optical fiber to generate a light receiving signal, and a measurement for obtaining the displacement of the measurement object based on the light receiving signal. It has a control unit. The head unit includes a display unit, and the measurement control unit is based on an operation state of the control device, a light reception waveform consisting of light reception intensity for each wavelength, or a calculation result based on at least one of displacement measurement values. , Control the display of the display unit.

In this confocal displacement meter, the end face of the optical fiber that transmits the light for projection between the head unit and the control device can function as a pinhole of the confocal optical system. In addition, since the display of the display unit is controlled by using the received light waveform and the measured value of the displacement, when installing the head unit, it is easy to indicate whether or not the head unit is properly installed by displaying the display unit. Can be identified. Further, since the display of the display unit is controlled on the control device side, it is possible to suppress the complicated configuration of the head unit. Further, since the display of the display unit is controlled by using the operating state of the control device, it is possible to easily identify whether or not the control device is operating normally in the vicinity of the installation location of the head unit.

In the cofocal displacement meter according to the second aspect of the present invention, in addition to the above configuration, the control device has a display light source that generates display light, and the fiber cable is an optical fiber that transmits the display light. The display unit is configured to display by the display light transmitted from the display light source via the optical fiber.

According to such a configuration, since the display light source is located on the control device side, it is not necessary to provide the display electric circuit and the wiring board in the head unit, and it is possible to suppress the head unit from becoming large in size. Further, since the heat generation of the display unit is suppressed, it is possible to suppress the deterioration of the measurement accuracy due to the temperature rise of the optical member, the jig supporting the head unit, and the like.

In the confocal displacement meter according to the third aspect of the present invention, in addition to the above configuration, the display unit rotates the emission end of a plurality of optical fibers transmitting the display light around the light projection axis of the detection light. It is formed by arranging in the direction. According to such a configuration, the display of the display unit can be confirmed from a plurality of positions in the circumferential direction about the optical axis, so that the visibility of the display unit can be improved.

In the confocal displacement meter according to the fourth aspect of the present invention, in addition to the above configuration, the display unit is arranged on the control device side of the emission end of the optical fiber that transmits the light from the light projection light source. .. According to such a configuration, it is possible to prevent the display light from entering the optical path of the detection light and reducing the measurement accuracy.

In the confocal displacement meter according to the fifth aspect of the present invention, in addition to the above configuration, the display unit is an optical fiber that transmits light from the light source for projection among a plurality of lenses constituting the optical member. It is arranged closer to the control device than the lens closest to the emission end. According to such a configuration, it is possible to prevent the configuration of the head unit from becoming complicated.

In the confocal displacement meter according to the sixth aspect of the present invention, in addition to the above configuration, the display unit has a display light source, and the measurement control unit controls the display light source to perform display. It is composed. According to such a configuration, since the display light source is located on the head unit side, it is not necessary to provide the display electric circuit and the wiring board in the control device, and it is possible to suppress the control device from becoming large in size.

In the confocal displacement meter according to the seventh aspect of the present invention, in addition to the above configuration, the measurement control unit specifies the peak intensity of the light receiving waveform consisting of the light receiving intensity for each wavelength, and the display is performed according to the peak intensity. It is configured so that the display mode of the unit is different. According to such a configuration, whether or not the installation state of the head unit is appropriate can be easily identified by the display mode of the display unit.

In the confocal displacement meter according to the eighth aspect of the present invention, in addition to the above configuration, the display mode of the display unit depends on whether or not the displacement obtained by the measurement control unit is within the range specified in advance. Is configured to be different. With such a configuration, the quality of the measurement target can be easily identified by the display mode of the display unit.

In the confocal displacement meter according to the ninth aspect of the present invention, in addition to the above configuration, the measurement control unit controls the display of the display unit in response to the light receiving signal. According to such a configuration, the display of the display unit can be changed according to the received light signal.

In the confocal displacement meter according to the tenth aspect of the present invention, in addition to the above configuration, the measurement control unit controls the display of the display unit based on a signal input from the outside of the control device. According to such a configuration, the display of the display unit can be changed according to the signal from the outside.

In the confocal displacement meter according to the eleventh aspect of the present invention, in addition to the above configuration, the fiber cable transmits the light from the light projection light source and the light from the display light source to the optical fiber for measurement which transmits the light from the light projection light source. It has an optical fiber for display, and the end on the control device side is branched in a bifurcated manner, and a detection light connector and a display light connector are attached, respectively, and the detection light connector and the display light connector are attached. The connector is detachably connected to the control device. According to such a configuration, the detection light connector and the display light connector can be individually attached and detached.

In the confocal displacement meter according to the twelfth aspect of the present invention, in addition to the above configuration, the display unit displays whether or not the measured value of the displacement is within the tolerance range. With such a configuration, it is possible to easily identify whether or not the measured value is within the tolerance range in the vicinity of the installation location of the head unit.

In the confocal displacement meter according to the thirteenth aspect of the present invention, in addition to the above configuration, the measurement control unit changes the display of the display unit by changing the blinking frequency or the blinking pattern. With such a configuration, the display content of the display unit can be easily identified.

In the confocal displacement meter according to the fourteenth aspect of the present invention, in addition to the above configuration, the head unit is composed of a cylindrical housing, and the display unit is arranged on the outer peripheral surface of the housing. According to such a configuration, the display on the display unit can be easily confirmed even when the head unit is held by the mounting member.

In the confocal displacement meter according to the fifteenth aspect of the present invention, in addition to the above configuration, the head unit is composed of a rectangular parallelepiped housing, and the display portion is arranged at a corner portion or a side surface of the housing. According to such a configuration, even if the head unit is installed with one side surface of the housing in contact with a structure such as a pillar, the display on the display unit can be easily confirmed.

According to the present invention, since the display of the display unit is controlled based on the received light signal, it is possible to easily identify whether or not the head unit is properly installed when the head unit is installed. Further, since the display of the display unit is controlled on the control device side, it is possible to improve the workability at the time of installing the head unit while suppressing the complicated configuration of the head unit. Therefore, it is possible to provide a confocal displacement meter with improved workability when installing the head unit.

It is a system diagram which showed one configuration example of the confocal displacement meter 1 by embodiment of this invention. It is sectional drawing which shows the structural example of the head unit 2 of FIG. 1 schematically. It is sectional drawing which showed the structural example of the display part 22 of FIG. It is a perspective view which showed the display part 22 of FIG. It is sectional drawing which showed the display part 22 of FIG. It is a perspective view which showed the display part 22 of FIG. It is a figure which showed the structural example of the light source 41 for projection of FIG. It is explanatory drawing which shows the structural example of the spectroscope 43 of FIG. 1 schematically. It is sectional drawing which showed the structural example of the light source 46 for display of FIG. It is a figure which showed the appearance of the head unit 2, the fiber cable 3 and the control device 4 of FIG. It is explanatory drawing which showed typically the use example of the confocal displacement meter 1 of FIG. It is explanatory drawing which showed the other structural example of the confocal displacement meter 1 schematically, and shows the transmission type spectroscope 43a. It is explanatory drawing which showed the other structural example of the head unit schematically, and shows the head units 2c and 2d which have the rectangular parallelepiped housing 20e.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification, for convenience, the direction of the optical axis of the head unit is described as the vertical direction, but the posture and orientation when the head unit is used are not limited.

<Confocal displacement meter 1>
FIG. 1 is a system diagram showing a configuration example of a confocal displacement meter 1 according to an embodiment of the present invention. The confocal displacement meter 1 is composed of a head unit 2, a fiber cable 3, and a control device 4, and receives the reflected light from the measurement object W when the detection light DL is emitted from the head unit 2 to receive the measurement object. It is an optical measuring device that measures the displacement of W.

The head unit 2 and the control device 4 are connected to each other via a fiber cable 3. The fiber cable 3 is composed of optical fibers 31 and 32 that transmit light. The optical fiber 31 is a transmission medium for transmitting light for projection. On the other hand, the optical fiber 32 is a transmission medium for transmitting light for display.

The optical fiber 31 and the optical fiber 32 are configured by the same optical fiber. Therefore, a common connector can be used for the connection portion of the optical fiber 31 and the connection portion of the optical fiber 32.

The optical fiber 32 is, for example, a bundle fiber or a multi-core fiber in which a plurality of optical fibers are bundled. A connector 33 is provided at one end of the fiber cable 3 and is detachably connected to the control device 4.

The head unit 2 is an optical unit that emits the detected light DL toward the measurement object W and incidents the reflected light from the measurement object W, and displays the optical members 21 such as the refraction lens 211 and the diffraction lens 212. A unit 22 is provided. The optical member 21 causes axial chromatic aberration in the detected light DL emitted through the end face of the optical fiber 31, and causes the detected light DL to converge toward the measurement object W. Axial chromatic aberration is color shift of an image in the optical axis direction due to dispersion.

In the cofocal displacement meter 1, light for projection is transmitted to the head unit 2 via the optical fiber 31, and an irradiation spot is formed on the measurement object W by the detection light DL emitted from the head unit 2. The emission end face of the optical fiber 31 functions as a pinhole through which the light from the light projecting light source 41 passes so as to be a point light source that emits the detection light DL, and also passes through the optical member 21 to the measurement object W. Of the irradiated detection light DL, it functions as a pinhole for passing the detection light of the reflected wavelength while focusing on the measurement object W.

The display unit 22 is provided near the connection portion between the head unit 2 and the fiber cable 3, and displays various information by using the display light transmitted from the display light source 46 via the optical fiber 32.

The control device 4 is a processing unit that controls light emission and reception and obtains the displacement of the object W to be measured based on the reflected light corresponding to the irradiation spot, and is a light source 41 for projection, a coupler 42, a spectroscope 43, and measurement control. It is composed of a unit 44, a memory 45, and a display light source 46. For example, based on the received light signal, the intensity of the light for projection, the exposure time when receiving the reflected light, and the gain when amplifying the received light signal are controlled. The light source 41 for floodlight is a light source device that produces light having a plurality of wavelengths, for example, white light as light for floodlight.

The coupler 42 is a directional coupler that outputs the light input from the light projecting light source 41 toward the head unit 2, while outputting the detection light DL input from the head unit 2 toward the spectroscope 43. .. The coupler 42 is a Y coupler in which two optical fibers 421 and 422 extend from one end and one optical fiber 423 extends from the other end.

The light from the light projecting light source 41 is input to the incident end of the optical fiber 421 and output to the optical fiber 31 via the optical fiber 423 and the connector 33. On the other hand, the detection light DL reflected by the measurement object W is input to the optical fiber 423 via the optical fiber 31 and the connector 33, and is emitted from the emission end of the optical fiber 422 toward the spectroscope 43.

The spectroscope 43 disperses the detected light DL that has passed through the emission end face of the optical fiber 31 and generates a light receiving signal. The measurement control unit 44 obtains the displacement of the measurement object W based on the light receiving signal of the spectroscope 43, and outputs the measured value to a display device or an external device (not shown).

Specifically, the displacement of the object to be measured W is calculated by acquiring a light receiving waveform consisting of the light receiving intensity for each wavelength from the spectroscope 43 and specifying the peak position of the light receiving waveform. The peak position is the pixel position where the light receiving intensity is the maximum, and corresponds to a specific wavelength. The memory 45 holds measurement conditions and various correction information.

The display light source 46 is a light source device that generates display light. The display light is, for example, visible light having a color different from that of the light for projection, is input to the incident end of the optical fiber 47, and is output to the optical fiber 32 via the connector 33. The connector 33 connects the optical fiber 423 from the coupler 42 and the optical fiber 47 from the display light source 46 to the optical fibers 31 and 32, respectively.

The measurement control unit 44 controls the display of the display unit 22 based on the received light signal of the spectroscope 43. Specifically, by controlling the display light source 46, various calculation results based on the received light signal and the operating state of the head unit 2 or the control device 4 are displayed on the display unit 22.

The measurement control unit 44 specifies the peak intensity of the received light waveform in order to be able to identify whether or not the installation state of the head unit 2 is appropriate, and displays the display mode of the display unit 22 according to the peak intensity. Make it different. Specifically, the peak intensity is compared with a predetermined determination threshold value, and the display color of the display unit 22 is changed depending on whether or not the peak intensity is equal to or higher than the determination threshold value. For example, if the peak intensity is equal to or higher than the determination threshold value, it is determined that the installation state of the head unit 2 is appropriate, and the display unit 22 lights up in blue. On the other hand, when the peak intensity is less than the determination threshold value, it is determined that the installation state of the head unit 2 is inappropriate, and the display unit 22 lights up in red.

The lighting pattern of the display unit 22 may be different depending on whether or not the peak intensity is equal to or higher than the determination threshold value. For example, if the peak intensity is equal to or higher than the determination threshold value, the display unit 22 is continuously lit, while if the peak intensity is less than the determination threshold value, the display unit 22 blinks. Further, depending on the peak intensity, the time length of the lighting state or the extinguishing state may be different, or the ratio of the lighting state and the extinguishing state may be different while keeping the blinking cycle constant.

Further, the measurement control unit 44 changes the display mode of the display unit 22 depending on whether or not the obtained displacement is within the range specified in advance in order to be able to discriminate the quality of the measurement object W. .. For example, if the measured value of the displacement is within the range, it is determined that the measurement object W is appropriate, and the display unit 22 lights up in blue. On the other hand, when the measured value of the displacement is out of the range, it is determined that the measurement object W is inappropriate, and the display unit 22 lights up in red.

Further, the measurement control unit 44 changes the display mode of the display unit 22 according to the operating state of the control device 4. For example, the display color or lighting pattern of the display unit 22 is changed depending on whether or not the light source for floodlight 41 is lit. Further, depending on the operation mode of either the installation state determination mode for determining whether the installation state of the head unit 2 is appropriate or the quality determination mode for determining the quality of the measurement target W. , The display color or lighting pattern of the display unit 22 is different. In addition, in order to make it possible to identify three or more operating states, display may be performed by switching between three or more display colors or lighting patterns.

Due to the display control by the measurement control unit 44 as described above, the display unit 22 has a system error during operation, whether or not the measurement object W is within the measurement range, and the measured value of the displacement is within the tolerance range. Whether or not it is displayed. For example, a malfunction such as a communication failure is displayed as a system error. Further, the display of the display unit 22 is controlled based on the signal input from the outside of the control device 4.

Further, a state in which the measured displacement value is above the upper limit threshold value (High), a state in which the measured value of displacement is below the lower limit threshold value (Low), and a state in which the measured value of displacement is equal to or greater than the lower limit threshold value and equal to or less than the upper limit threshold value. (Go) is displayed so that it can be identified. Further, the display unit 22 displays whether or not the head unit 2 is properly installed. The measurement control unit 44 makes the display of the display unit 22 different by changing the blinking frequency or the blinking pattern.

An X coupler may be used for the coupler 42. The X coupler is more likely to suppress the reflection of the end face than the Y coupler. Such an optical fiber coupler is a fusion type coupler in which a plurality of optical fibers are fused, but may be a type of coupler that splits light by using a beam splitter. Further, instead of the connector 33, two independent connectors for individually connecting the optical fiber 31 for light projection and the optical fiber 32 for display may be used.

<Head unit 2>
FIG. 2 is a cross-sectional view schematically showing a configuration example of the head unit 2 of FIG. 1, and shows a cut surface when the head unit 2 is cut by a plane including an optical axis J. The head unit 2 is composed of a housing 20, an optical member 21, a display unit 22, and an optical fiber ferrule 23.

The housing 20 is, for example, a covered cylindrical lens barrel, and the central axis is the optical axis J. The diameter of the housing 20 changes along the optical axis J, and the tip side has a large diameter portion 20a, and the root side has a small diameter portion 20b having a smaller diameter than the large diameter portion 20a. The small diameter portion 20b is a metal fitting mounting portion to which a mounting metal fitting for a jig that supports the head unit 2 is mounted. That is, the small diameter portion 20b of the head unit 2 is a holding portion held by the mounting member when the head unit 2 is installed on the production line. Further, a connection portion 20c is formed between the small diameter portion 20b and the tip of the fiber cable 3.

The optical member 21 is composed of a refraction lens 211, a diffraction lens 212, and optical lenses 213 and 214. The refraction lens 211 is an optical lens that collects or diffuses incident light by utilizing the refraction phenomenon of light. The refraction lens 211 is, for example, an aspherical lens.

The diffractive lens 212 is an optical lens that collects or diffuses incident light by utilizing the diffraction phenomenon of light, and is arranged so as to be exposed through the lower end opening of the large diameter portion 20a, that is, the floodlight window 20d. There is. The diffractive lens 212 is a relief type diffractive lens, and a fine relief (undulation) is formed on the diffractive surface (upper surface) on which the detection light DL from the optical fiber ferrule 23 is incident. The relief has a depth in the optical axis direction of about the wavelength of light, and a plurality of annular patterns centered on the optical axis J are arranged. The lower surface of the diffractive lens 212 is a flat surface.

The optical lenses 213 and 214 are both refracting lenses that collect the detection light DL from the optical fiber ferrule 23. The diffraction lens 212, the refraction lens 211, and the optical lens 214 are arranged in the large diameter portion 20a, and the optical lens 213 is arranged in the small diameter portion 20b.

Although the refraction lens 211, the diffractive lens 212, and the optical lenses 213 and 214 are all single lenses, they may be compound lenses in which a plurality of optical lenses are combined. Further, it is preferable that the optical member 21 includes a lens element having a low Abbe number, such as the diffractive lens 212.

The optical fiber ferrule 23 is a holding member that holds the optical fiber 31 constituting the fiber cable 3, and the emission end of the optical fiber 31 is held by the resin member. The optical fiber ferrule 23 is arranged so as to project downward from the canopy portion of the housing 20.

The optical fiber 31 is composed of a core and a clad, and the end face of the core functions as a pinhole. That is, the end surface of the core of the optical fiber 31 has a sufficiently small diameter as compared with the space in which the emission end of the optical fiber 31 is arranged, and the incident light can be selectively passed through the optical member 21. The refracting lens 211, the optical lenses 214 and 213 are arranged between the optical fiber ferrule 23 and the diffractive lens 212. The emission end face of the optical fiber 31 and the optical member 21 form a cofocal optical system.

This confocal optical system narrows down the light received by using the confocal principle and causes axial chromatic aberration in the detected light DL. Therefore, the detection light DL emitted from the emission end surface of the optical fiber 31 and transmitted through the optical member 21 is imaged at different positions in the vertical direction depending on the wavelength. Of the wavelength components contained in the detection light DL, the specific wavelength component imaged on the measurement target W is reflected by the measurement target W, and the reflected light passes through the optical member 21 and is emitted from the optical fiber 31. An image is formed on the end face. On the other hand, the reflected light corresponding to the wavelength component other than the specific wavelength component is not imaged on the emission end surface of the optical fiber 31, and is blocked.

In the cofocal displacement meter 1, the emission end surface 23a of the optical fiber ferrule 23 is obliquely processed in order to suppress a decrease in measurement accuracy due to the influence of light reflected by the emission end surface of the optical fiber 31. That is, the emission end surface 23a is an inclined surface inclined with respect to a plane perpendicular to the central axis of the optical fiber ferrule 23. The inclination of the emission end surface 23a is formed by, for example, polishing. Further, the optical fiber ferrule 23 is arranged so that its central axis is inclined with respect to the optical axis J in consideration of the refraction when the detection light DL passes through the emission end surface of the optical fiber 31.

The distance from the head unit 2 to the object W to be measured is, for example, about 10 mm to 70 mm, and the measurement range MR is about 1 mm to 20 mm. This measurement range MR corresponds to the bandwidth of the detection light DL, and a wide band detection light DL is used in order to secure a wide measurement range MR. The detection light DL contains, for example, a wavelength component of 500 nm to 700 nm.

The display unit 22 is provided in the connection unit 20c of the housing 20, and is composed of an emission end of the optical fiber 32, a diffusion window 221 and a reflection member 222. The reflection member 222 is an optical member for reflecting the display light emitted through the emission end surface 32a of the optical fiber 32 toward the diffusion window 221. The diffusion window 221 is composed of an optical member that diffuses the display light, and is exposed from the outer peripheral surface of the connection portion 20c.

Since the display is performed by emitting the display light through the emission end surface of the optical fiber 32 and diffusing it through the diffusion window 221, the head unit 2 does not have an electric circuit or a wiring board for display. Therefore, it is possible to prevent the head unit 2 from becoming large. Further, since the heat generation of the display unit 22 is suppressed, it is possible to suppress the deterioration of the measurement accuracy due to the temperature rise of the jig supporting the optical member 21 and the head unit 2.

In the display unit 22, the emission end of the optical fiber 32 is arranged with the emission end surface 32a facing downward, and the reflection member 222 transmits the display light emitted through the emission end surface 32a in the radial direction centered on the optical axis J. Reflect outward. The diffusion window 221 extends in the circumferential direction about the optical axis J and has a wide viewing angle in the circumferential direction. Further, the display unit 22 is arranged on the control device 4 side of the emission end of the optical fiber 31 in order to prevent the display light from entering the optical path of the detection light DL and reducing the measurement accuracy.

Further, the display unit 22 is arranged closer to the control device than the optical lens 213 closest to the emission end of the optical fiber 31 among the plurality of lenses constituting the optical member 21. According to such a configuration, since it is not necessary to arrange the optical fiber 32 across the optical lens 213, it is possible to suppress the configuration of the head unit 2 from becoming complicated.

<Display unit 22>
FIG. 3 is a cross-sectional view showing a configuration example of the display unit 22 of FIG. 2, and shows a cut surface when the display unit 22 is cut by the AA cutting line. FIG. 4 is a perspective view showing the display unit 22 of FIG. 2, and shows a case where the display unit 22 is viewed from diagonally below. FIG. 5 is a cross-sectional view showing the display unit 22 of FIG. 2, showing a cut surface formed by a plane including the optical axis J. FIG. 6 is a perspective view showing the display unit 22 of FIG. 2, and shows the connection unit 20c of the housing 20. The display unit 22 is formed by arranging the emission ends of a plurality of optical fibers constituting the optical fiber 32 in the light projecting axis of the detection optical DL, that is, in the circumferential direction centered on the optical axis J.

The optical fiber 32 is, for example, a bundle fiber or a multi-core fiber in which a large number of optical fibers 32b are bundled by a sheath, and the emission ends of the optical fibers 32b exposed from the sheath are adjacent to each other without a gap in the circumferential direction. It is arranged. Each emission end of the optical fiber 32b is arranged in a row along the outer peripheral surface of the connecting portion 20c within a range where the central angle around the optical axis J is about 180 °, and a viewing angle of 180 ° or more is secured. ing.

By adopting such a configuration, the display of the display unit 22 can be confirmed from a plurality of positions in the circumferential direction about the optical axis J, so that the visibility of the display unit 22 can be improved.

<Light source for floodlight 41>
7A and 7B are views showing a configuration example of the light source for floodlight 41 of FIG. 1. FIG. 7A shows a side surface of the light source for floodlight 41, and FIG. 7B shows a light source for floodlight 41. The cut surface when the light source is cut by the BB cutting line is shown. The light source for projection 41 is a light source device that irradiates a phosphor with laser light to generate white light, and is a light emitting element 411, a wiring board 412, an element holder 413, a condenser lens 414, a lens holder 415, and a ferrule 416. , A ferrule presser 417, a phosphor 50, a frame 51, and a filter element 52.

The light emitting element 411 is a semiconductor light emitting device such as a laser diode (LD) and generates a laser beam having a single wavelength. The light emitting element 411 is arranged on the wiring board 412 with the light emitting portion facing forward in the horizontal direction. For example, the light emitting device 411 produces blue light or ultraviolet light having a wavelength of 450 nm or less. The element holder 413 is a member that holds the wiring board 412, and is inserted into the lens holder 415 from the back surface side.

The condenser lens 414 is an optical member that concentrates the laser light emitted from the light emitting element 411 on the incident end of the optical fiber 421, and is arranged so as to face the light emitting element 411. The lens holder 415 is a lens barrel that holds the condenser lens 414, and has a reduced diameter in front of the condenser lens 414. The ferrule 416 is a cylindrical connecting member in which the incident end of the optical fiber 421 is incorporated and extends in the front-rear direction. The ferrule presser 417 is a bottomed cylindrical member for fixing the ferrule 416 inserted from the front side to the reduced diameter portion of the lens holder 415, and the cylindrical portion is covered with the outer peripheral surface of the reduced diameter portion. It is attached to the lens holder 415.

The phosphor 50 is a light emitter that is excited by the laser light from the light emitting element 411 and generates fluorescence having a wavelength different from that of the laser light. The outer peripheral surface of the phosphor 50 is held by the frame 51 and is arranged in the lens holder 415 in a state of being in contact with the incident end surface of the optical fiber 421. For example, the phosphor 50 generates yellow fluorescence by irradiation with a blue laser beam. The fluorescent substance 50 may be formed of two or more types of fluorescent materials. For example, the phosphor 50 is formed of a fluorescent material that generates green fluorescence and a fluorescent material that generates red fluorescence when irradiated with a blue laser beam.

The filter element 52 is an optical member that transmits the laser light from the light emitting element 411 and reflects the light from the phosphor 50, and is arranged so as to cover the surface of the frame 51 on the light emitting element side. Light having a plurality of wavelengths, which is a mixture of laser light from the light emitting element 411 and fluorescence from the phosphor 50, is incident on the incident end of the optical fiber 421.

The light projecting light source 41 has a configuration in which light obtained by mixing laser light from the light emitting element 411 and fluorescence from the phosphor 50 is directly incident on the incident end of the optical fiber 421. By using such a fiber type light source, it is possible to simplify the connection between the head unit 2 and the control device 4 with the fiber cable 3.

As the light source for projection 41, a light source that generates a wide band of light, for example, a halogen lamp, an SC light source that generates supercontinium (SC) light, or a super luminescent diode (SLD) may be used. Further, ordinary white LED light may be used. The SC light source produces a continuous and wide band laser beam by the nonlinear optical effect of the pulse laser.

<Spectroscope 43>
FIG. 8 is an explanatory diagram schematically showing a configuration example of the spectroscope 43 of FIG. 1, and shows a reflection type spectroscope 43. The spectroscope 43 is composed of a collimator lens 431, a diffraction grating 432, an imaging lens 433, and an image sensor 434, and disperses the detection light DL emitted from the emission end of the optical fiber 422 of the coupler 42.

The emission end of the optical fiber 422, the diffraction grating 432 and the image sensor 434 are arranged, for example, in the horizontal direction. The collimator lens 431 is an optical lens for obtaining parallel light, and is arranged so as to face the emission end surface of the optical fiber 422.

The diffraction grating 432 is a reflection type color dispersion element that reflects the detected light DL at different angles depending on the wavelength, and has a flat plate shape. The imaging lens 433 forms an image of the detection light DL separated by the diffraction grating 432 on the image sensor 434. Although the collimator lens 431 and the imaging lens 433 are both single lenses, they may be compound lenses in which a plurality of optical lenses are combined.

The image sensor 434 is, for example, a one-dimensional line image sensor extending in the horizontal direction, and a large number of light receiving elements are linearly arranged. A light receiving waveform is formed by the light receiving signal of each light receiving element. The image sensor 434 may use an image pickup element in which a large number of light receiving elements are two-dimensionally arranged.

The diffraction grating 432 is slightly tilted from the state facing the light receiving surface of the image sensor 434 in order to prevent the light incident on the image sensor 434 from being specularly reflected on the light receiving surface and reflected by the diffraction grating 432 to be received again. Is placed. The detection light DL may be separated by using a prism.

<Display light source 46>
FIG. 9 is a cross-sectional view showing a configuration example of the display light source 46 of FIG. 1, showing a cut surface when the display light source 46 is cut by a plane including the central axis of the incident end of the optical fiber 47. There is. The display light source 46 is a light source device for generating display light, and is composed of a light emitting element 461, a wiring board 462, a ferrule 463, and an element holder 464.

The light emitting element 461 is composed of, for example, a plurality of light emitting diodes (LEDs) having different light emitting colors, and is arranged on the wiring board 462 with the light emitting unit oriented in the horizontal direction. The element holder 464 is a holding member for holding the wiring board 462 and the ferrule 463. The ferrule 463 is a cylindrical connecting member in which the incident end of the optical fiber 47 is incorporated and extends in the front-rear direction. Since the display light source 46 is a fiber type light source in which the display light from the light emitting element 461 is directly incident on the incident end of the optical fiber 47, the connection with the fiber cable 3 can be simplified.

FIG. 10 is a diagram showing the appearance of the head unit 2, the fiber cable 3, and the control device 4 of FIG. 1, and one end of the fiber cable 3 extending from the head unit 2 is detachably connected to the front surface of the housing of the control device 4. The case is shown. The fiber cable 3 extending from the head unit 2 is a single cable containing an optical fiber 31 for measurement and an optical fiber 32 for display, and the end portion on the control device side is bifurcated into two. Connectors 33a and 33b are attached to the ends of the branch cables, respectively.

The connector 33a is a connection member for display light for detachably connecting the optical fiber 32 for display to the connection port for display light provided in the control device 4. On the other hand, the connector 33b is a connection member for detection light for detachably connecting the optical fiber 31 for measurement to the connection port for detection light provided in the control device 4. The connectors 33a and 33b can be individually attached to and detached from the connection port of the control device 4.

FIG. 11 is an explanatory diagram schematically showing a usage example of the confocal displacement meter 1 of FIG. 1, in which two head units 2 are arranged so as to face each other to determine the thickness of an opaque measurement object W. The state of measurement is shown. In (a) in the figure, the case where the optical axis Ja of the upper head 2a facing the measurement object W and the optical axis Jb of the lower head 2b substantially coincide with each other is shown.

The object W to be measured is a long sheet-like object extending in the horizontal direction, and the thickness during transportation in one of the left and right directions is measured at a predetermined timing. The upper head 2a and the lower head 2b are both head units 2, and the projection window 20d is arranged so as to face the surface of the measurement object W.

Further, in order to accurately measure the thickness of the object W to be measured, it is necessary to match the optical axis Ja of the upper head 2a with the optical axis Jb of the lower head 2b. If the optical axes Ja and Jb are displaced in the horizontal direction, or if the optical axes Ja and Jb are not parallel, the error when the measurement object W is tilted due to warpage or bending becomes large, so the thickness of the measurement object W. Cannot be measured correctly.

In (b) in the figure, the case where the optical axis Ja of the upper head 2a is displaced in the horizontal direction with respect to the lower head 2b is shown. If the optical axes Ja and Jb are displaced in this way, an error in measuring the thickness increases.

The thickness of the object to be measured W is calculated by a predetermined calculation from the displacement measured by the upper head 2a and the displacement measured by the lower head 2b. The quality determination of the measurement object W is performed based on the comparison result of comparing the measured value of the calculated thickness with the quality determination threshold value.

In order to accurately measure the thickness of the object W to be measured during transportation, it is necessary to match the timing of measuring the displacement between the upper head 2a and the lower head 2b. If there is a deviation in this timing, even if the optical axes Ja and Jb are aligned, an error in measuring the thickness will increase due to the influence of vibration and blurring.

The optical axis adjustment for aligning the optical axes J of the two head units 2 with each other is performed while confirming the result of the suitability determination as to whether or not the installation state of the head unit 2 is appropriate by the display of the display unit 22. .. This suitability determination is performed based on a comparison result in which the peak intensity of the received light waveform measured by the upper head 2a or the lower head 2b is compared with the suitability determination threshold value.

According to the present embodiment, since the display of the display unit 22 is controlled by using the received light waveform and the measured value of the displacement, whether or not the head unit 2 is properly installed when the head unit 2 is installed. Can be easily identified by the display on the display unit 22. Further, since the display of the display unit 22 is controlled on the control device 4 side, it is possible to prevent the configuration of the head unit 2 from becoming complicated. Further, since the display of the display unit 22 is controlled by using the operating state of the control device 4, it is possible to easily identify whether or not the control device 4 is operating normally in the vicinity of the installation location of the head unit 2. can.

Further, since the display light source 46 is located on the control device 4, it is not necessary to provide the head unit 2 with an electric circuit for display and a wiring board, and it is possible to suppress the head unit 2 from becoming large in size. Further, since the heat generation of the display unit 22 is suppressed, it is possible to suppress the deterioration of the measurement accuracy due to the temperature rise of the optical member 21, the jig supporting the head unit 2, and the like.

In the present embodiment, an example of the reflection type spectroscope 43 has been described, but the present invention does not limit the configuration of the spectroscope to this. For example, a transmission type spectroscope that separates incident light into different wavelength components depending on the transmission angle may be used.

FIG. 12 is an explanatory diagram schematically showing another configuration example of the confocal displacement meter 1, and shows a transmission type spectroscope 43a. The spectroscope 43a differs from the spectroscope 43 of FIG. 8 in that the diffraction grating 435 is a transmission type. The diffraction grating 435 is a color dispersion element that disperses incident light into different wavelength components depending on the transmission angle.

The detection light DL emitted from the emission end of the optical fiber 422 is incident on the diffraction grating 435 via the collimator lens 431. The detection light DL transmitted through the diffraction grating 435 is incident on the image sensor 434 via the imaging lens 433.

Further, in the present embodiment, an example in which the display light source 46 is provided on the control device 4 side has been described, but the present invention can also be applied to a display light source provided on the head unit 2 side. .. For example, the display unit 22 of the head unit 2 may have a display light source, and the measurement control unit 44 of the control device 4 may be configured to perform display by controlling the display light source. According to such a configuration, since the display light source is on the head unit 2 side, it is not necessary to provide the display electric circuit and the wiring board in the control device 4, and it is possible to prevent the control device 4 from becoming large in size. Can be done.

Further, in the present embodiment, an example in which the head unit 2 is composed of a cylindrical housing 20 has been described, but the present invention does not limit the shape of the head unit to this. For example, the head unit may be composed of a rectangular parallelepiped housing, and the display unit 22 may be arranged on the side surface of the housing.

FIG. 13 is an explanatory diagram schematically showing another configuration example of the head unit, and shows the head units 2c and 2d made of a rectangular parallelepiped housing 20e. In (a) in the figure, the head unit 2c in which the display unit 22 is arranged at the corner of the housing 20e is shown. The head unit 2c is composed of a rectangular parallelepiped housing 20e that is long in the vertical direction, and is installed, for example, in a state where one side surface of the housing 20e is in contact with a structure K such as a pillar or a wall.

If one side surface of the housing 20e that comes into contact with the structure K is called a mounting surface, the display unit 22 is arranged at a corner portion composed of two adjacent side surfaces among the side surfaces other than the mounting surface. By arranging in this way, the visibility of the display unit 22 can be improved.

In (b) in the figure, the head unit 2d in which the display unit 22 is arranged on the non-mounting surface of the housing 20e is shown. The display unit 22 is arranged on one side surface other than the mounting surface of the housing 20e. By arranging in this way, the display unit 22 can be satisfactorily visually recognized even when the head unit 2d is installed in the structure K.

1 Confocal displacement meter 2 Head unit 20 Housing 20a Large diameter part 20b Small diameter part 20c Connection part 21 Optical member 211 Refractive lens 212 Diffractive lens 213,214 Optical lens 22 Display unit 221 Diffuse window 222 Reflective member 23 Optical fiber ferrule 3 Fiber Cable 31, 32 Optical fiber 33 Connector 4 Control device 41 Light source for floodlight 42 Coupler 43 Spectrometer 432 Diffraction grid 434 Image sensor 44 Measurement control unit 45 Memory 46 Display light source 461 Light emitting element 462 Wiring board 463 Ferrule 47 Optical fiber

Claims (13)

A fiber cable consisting of a head unit having a confocal optical system, a control device having a light source for floodlight that generates light containing a plurality of wavelengths, and an optical fiber that transmits light from the light source for floodlight to the head unit. It is a cofocal displacement meter equipped with
The head unit has an optical member that causes axial chromatic aberration in the detection light emitted through the end face of the optical fiber and converges the detection light toward an object to be measured.
Detection that the control device has passed through the end face of the optical fiber by being reflected while being in focus on the measurement object among the detection light emitted to the measurement object via the optical member. In a confocal displacement sensor having a spectroscope that disperses light and generates a light receiving signal, and a measurement control unit that obtains a displacement of the measurement object based on the light receiving signal.
The head unit includes a display unit and has a display unit.
The measurement control unit controls the display of the display unit based on the operation state of the control device, the light reception waveform consisting of the light reception intensity for each wavelength, or the calculation result based on at least one of the measured values of the displacement.
The control device has a display light source that produces display light.
The fiber cable has a bundle fiber or a multi-core fiber in which a plurality of optical fibers for transmitting the display light are bundled.
The display unit is a plurality of optical fibers that transmit the display light, and the emission ends of the plurality of optical fibers are arranged side by side in the circumferential direction about the projection axis of the detection light. And the casing of the head unit via a reflective member that reflects the display light from the emission ends of a plurality of optical fibers arranged side by side in the circumferential direction outward about the projection axis of the detection light. Display is performed by the display light transmitted from the display light source on the outer peripheral surface of the body .
On the display light source side, the bundle fiber or the multi-core fiber is optically coupled to the display light source in a state in which a plurality of optical fibers transmitting the display light are bundled.
On the head unit side, a confocal displacement meter characterized in that a plurality of optical fibers transmitting the display light are unbound. The confocal displacement meter according to claim 1 , wherein the display unit is arranged closer to the control device than the emission end of the optical fiber that transmits light from the light source for projection. The display unit is characterized in that it is arranged closer to the control device than the lens closest to the emission end of the optical fiber that transmits the light from the light projecting light source among the plurality of lenses constituting the optical member. The confocal displacement meter according to claim 1 . The confocal displacement meter according to claim 1, wherein the display unit displays by controlling the display light source by the measurement control unit. Any of claims 1 to 4 , wherein the measurement control unit specifies a peak intensity of a light receiving waveform composed of a light receiving intensity for each wavelength, and changes the display mode of the display unit according to the peak intensity. Confocal displacement meter described in Crab. The invention according to any one of claims 1 to 5 , wherein the measurement control unit changes the display mode of the display unit depending on whether or not the obtained displacement is within a predetermined range. Confocal displacement meter. The confocal displacement meter according to any one of claims 1 to 6 , wherein the measurement control unit controls the display of the display unit in response to the light receiving signal. The confocal displacement meter according to any one of claims 1 to 7 , wherein the measurement control unit controls the display of the display unit based on a signal input from the outside of the control device. The fiber cable has an optical fiber for measurement that transmits light from the light projecting light source and an optical fiber for display that transmits light from the light source for display, and has an end portion on the control device side. A claim characterized in that the detection light connector and the display light connector are attached by bifurcating, respectively, and the detection light connector and the display light connector are detachably connected to the control device. Item 1. The cofocal displacement meter according to Item 1. The confocal displacement meter according to any one of claims 1 to 9 , wherein the display unit displays whether or not the measured value of the displacement is within the tolerance range. The confocal displacement meter according to any one of claims 1 to 10 , wherein the measurement control unit changes the display of the display unit by changing the blinking frequency or the blinking pattern. The head unit consists of a rectangular parallelepiped housing.
The confocal displacement meter according to any one of claims 1 to 11 , wherein the display unit is arranged at a corner portion or a side surface of the housing. The confocal displacement meter according to any one of claims 1 to 12 , wherein a diffusion member is provided in front of a plurality of optical fibers that transmit the display light at the emission end.

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