JP2012229983A - Displacement sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement sensor, even if being a compact size, capable of highly accurately measuring displacement of a measuring object without using a drive device.SOLUTION: The displacement sensor comprises an optical system including: a light projection section having a light source part; an irradiation section focusedly applying light emitted from the light source part to a measuring object; and a first light receiving section focusedly receiving the light that has been applied and reflected by the measuring object. The light projection section includes the light source part, a first lens, and a first half mirror. The irradiation section includes a first half mirror and a second lens. The first light receiving section includes a first half mirror and at least four holes, and each of the four holes has a slit plate disposed on an xy axis, a third lens, and a first light receiving element. The irradiation section and the first light receiving section are disposed in such a manner that an optical axis of the irradiation section matches an optical axis of the first light receiving section. The light projection section is disposed via the first half mirror such that an optical axis of the projection section orthogonally crosses with the optical axes of the irradiation section and the first light receiving section.

Description

  The present invention relates to an optical displacement sensor that receives reflected light of light applied to an object and detects the amount of displacement of the object based on the amount of light received.

  Conventionally, displacement sensors are often used for position control of manufacturing apparatuses used for manufacturing products, position control of products with respect to manufacturing apparatuses, or inspection of products. As such a displacement sensor, for example, as disclosed in Patent Document 1, a sensor that detects the displacement of an object using a triangulation method has been proposed. That is, the triangulation method is a method in which a target is irradiated with light in a certain irradiation direction, and reflected light reflected at a predetermined angle with respect to the irradiation direction is received by a position detection element or the like. The displacement amount of the object is measured based on the change in the center of gravity position of the light receiving spot on the position detection element that changes with the displacement of the object.

  However, the displacement sensor using this triangulation method cannot keep the spot diameter of the light irradiated to the object at a minute spot size such as the diffraction limit. That is, there is a problem that a minute spot size can be obtained only at one point as an irradiation condensing point, and the spot size is widened at most other positions.

  Therefore, for example, as shown in Patent Document 2, a coaxial optical system that includes a light projecting unit and a light receiving unit including a diaphragm and is adjusted so that the light emission position of the light projecting unit and the diaphragm are in a conjugate relationship. A lens unit including a lens that can reciprocate along the optical axis is provided on the optical axis, and the displacement of the measurement object is determined based on the position of the lens when the received light amount signal of the light receiving unit takes a maximum value. A displacement sensor for measurement has been proposed. That is, there has been proposed a displacement sensor that measures the displacement of an object to be measured based on the distance that the lens has moved by operating a reciprocating lens with the optical axes of the light projecting unit and the irradiation unit being coaxial. Yes.

  However, since such a displacement sensor requires a driving device for reciprocating the lens, there is a problem that the displacement sensor becomes large.

JP-A-8-240408 JP 2007-121122 A

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to measure the displacement of a measurement object with high accuracy even if it is small without using a driving device. It is to provide a displacement sensor that can be used.

  The object of the present invention is to provide a light projecting unit having a light source unit that emits light, an irradiation unit that collects and emits light emitted from the light source unit toward the measurement target, and the measurement target. A displacement sensor including an optical system including a first light receiving unit configured to collect and receive irradiated and reflected light, wherein the light projecting unit includes the light source unit and a first lens. The irradiation unit includes a second lens, and the first light receiving unit has at least four holes, and the four holes are respectively disposed on the xy axis, a third lens, A first light receiving element, the irradiating unit and the first light receiving unit are arranged so that an optical axis of the irradiating unit and an optical axis of the first light receiving unit coincide, the light projecting unit, Through the first half mirror, the optical axis of the light projecting unit intersects the optical axis of the irradiation unit and the first light receiving unit perpendicularly. It is achieved by providing a displacement sensor, characterized by being arranged.

  In addition, the object of the present invention is to provide a second light receiving part via a second half mirror between the first lens of the light projecting part and the first half mirror, and the second light receiving part is a first light receiving part. This is effectively achieved by providing a displacement sensor comprising four lenses and a second light receiving element.

  The present invention includes at least four holes, a light projecting unit including a light source unit, a first lens, an irradiation unit including a second lens, and the four holes are arranged on the xy axis. A slit plate, a third lens, and a first light receiving unit including a first light receiving element, and the lens is arranged so that the optical axis of the irradiation unit and the optical axis of the first light receiving unit coincide with each other. And since the 1st lens of the light projection part was arrange | positioned through the 1st half mirror so that the optical axis of a light projection part may cross | intersect the optical axis of an irradiation part and a 1st light-receiving part perpendicularly, thereby, a drive device Even if it is a small apparatus, the displacement of a measurement object can be measured with high accuracy.

It is a figure which shows the optical system with which the displacement sensor which concerns on this invention is provided. It is a top view of the slit board used for this invention. It is a top view which shows the example of a change of the slit board used for this invention. It is a figure which shows the example of a change of the optical system with which the displacement sensor which concerns on this invention is provided. It is a figure which shows another example of a change of the optical system with which the displacement sensor which concerns on this invention is provided. It is a figure which shows the top view of the aperture plate with which the displacement sensor which concerns on this invention is provided. It is a figure which shows another example of a change of the optical system with which the displacement sensor which concerns on this invention is provided. It is a figure which shows the change of the spot image (slit permeation | transmission light image) in the light-receiving surface by the movement of a measurement object, (A1)-(A3) are the movement states of a measurement object, (B1)-(B3) are respectively It is a figure which shows the state of the slit permeation | transmission light quantity in the light-receiving surface corresponding to this movement.

  FIG. 1 is a diagram showing an embodiment of an optical system provided in a displacement sensor 1 according to the present invention. That is, the displacement sensor 1 according to the present invention includes a light projecting unit 3 that emits light toward the measurement target 2 and a light from the light projecting unit 3 that is focused toward the measurement target 2 as illustrated. The irradiation unit 4 for irradiating and the first light receiving unit 5 that collects and receives the light irradiated and reflected on the measurement object 2 is configured.

  The light projecting unit 3 includes at least a light source unit 6 that emits light, a first lens 7, and a first half mirror 8, and the irradiation unit 4 includes a first half mirror 8, a second lens 9, and the like. The first light receiving unit 5 includes a first half mirror 8, a slit plate 10, a third lens 11, and a first light receiving element 12. As shown in the drawing, the first half mirror 8 is used in common by the light projecting unit 3, the irradiation unit 4, and the first light receiving unit 5.

  Here, the top view of the slit board 10 which the 1st light-receiving part 5 comprises in FIG. 2 is shown. As shown in the drawing, at least four holes 13 are formed in the slit plate 10. The four holes 13 are arranged so that the centers of the respective holes 13 are on the xy axis and face each other. The slit plate 10 is made of a material that does not transmit light, such as a black plastic plate. FIG. 3 shows a slit plate 10 </ b> A that is a modified example of the slit plate 10. As shown in FIG. 3, four or more even-numbered holes 13 may be formed so as to face each other. That is, it is only necessary that the slit plate 10 is formed so that at least four even-numbered holes 13 respectively arranged on the xy axis face each other. In this case, the center of each hole 13 is preferably on the same concentric circle centered on the center O of the slit plate 10. Further, the shape of the hole 13 is not limited to a rectangular shape as shown in the figure, and may be various known shapes such as an elliptical shape and a circular shape.

  As shown in FIG. 1, the optical system of the displacement sensor 1 according to the present invention includes an irradiation unit 4 and an optical unit 14 such that the optical axis 14 of the irradiation unit 4 and the optical axis 15 of the first light receiving unit 5 coincide. Each component of the 1st light-receiving part 5 is arrange | positioned. Further, the optical axis 16 of the light projecting unit 3 is disposed via the first half mirror 8 so as to be orthogonal to the optical axis 14 of the irradiation unit 4 and the optical axis 15 of the first light receiving unit 5. In the figure, the optical axes 14, 15, and 16 are indicated by alternate long and short dash lines.

  Next, the principle of measuring the displacement of the measurement object 2 by the displacement sensor 1 according to the present invention will be described.

  First, in the light projecting unit 3, the light emitted from the light source 6 passes through the first lens 7, is collimated to be substantially parallel light, and is irradiated onto the first half mirror 8. Then, this light enters the irradiation unit 4. At this time, if the diameter of the parallel light is 20 mm or more, the reflected light that passes through the slit plate 10 described later and is collected on the first light receiving element 12 is prevented from being excessively collected, and the measurement accuracy is further improved. Since it can improve, it is preferable.

  In the irradiation unit 4, the light irradiated to the first half mirror 8 by the light projecting unit 3 is changed in its optical path by the first half mirror 8, passes through the second lens 9, and reaches the surface of the measurement object 2. Irradiated. In the embodiment shown in FIG. 1, since the light that has been collimated by the first lens 7 is incident on the second lens 9, the measurement light (light irradiated from the light source onto the measurement object) is the measurement target. Condensate on the object 2.

  This irradiation light is reflected on the measurement object 2 and becomes reflected light. Then, the reflected light is incident again on the second lens 9 and collimated to become almost parallel light. Of the reflected light that has become the parallel light, the light that has passed through the first half mirror 8 enters the first light receiving unit 5.

  In the first light receiving unit 5, the reflected light passes through the hole 13 of the slit plate 10 and then enters the third lens 11 and forms an image on the light receiving surface of the first light receiving element 12. At this time, since the reflected light made parallel by the second lens 9 is incident on the third lens 11, the reflected light is focused on the light receiving surface of the first light receiving element 12 to form an image.

  FIG. 8 is a diagram illustrating a change in the spot image (slit transmitted light image) on the light receiving surface of the first light receiving element 12 due to the movement of the measurement object 2, and FIGS. FIGS. (B1) to (B3) show the state of movement of the slit and the amount of light transmitted through the slit on the light receiving surface of the first light receiving element 12 corresponding to each movement. As is clear from these figures, in the case of FIG. (A3), that is, when the measurement object 2 is not displaced, the amount of light received on the light receiving surface of the first light receiving element 12 as shown in black in FIG. (B3). Is the maximum and a focused spot image can be obtained. On the other hand, as shown in FIGS. (A1) and (A2), when the measurement object 2 is displaced, the spot image of the reflected light formed on the light receiving surface of the first light receiving element 12 is as shown in FIG. As shown in gray in B2), since the amount of received light decreases, the spot image becomes blurred. That is, by providing the slit plate 10 in the first light receiving unit 5, the measurement object 2 is displaced. More specifically, as described above, the interval between the spots formed on the light receiving surface of the first light receiving element 12 changes. This change is detected by the first light receiving element 12 as a light amount change, and the displacement amount of the measurement object 2 is detected by converting the light amount change into a distance.

  As described above, according to the displacement sensor 1 according to the present invention, a reciprocating lens or the like for measuring the displacement of the measurement object 2 is not required as in the prior art. As a result, since a driving device for moving the lens is not required, the displacement sensor can be reduced in size, and the displacement of the measurement object 2 can be measured and detected even if the size is reduced.

  Next, a modified example of the displacement sensor according to the present invention will be shown. FIG. 4 shows an optical system of a displacement sensor 1A according to a modification of the present invention. The optical system shown in FIG. 4 is the same as the optical system shown in FIG. 1 except for the second optical receiver 17 provided in the optical system shown in FIG. Therefore, the same components as those in FIG.

  FIG. 4 is a diagram showing a modification of the optical system of the displacement sensor 1A according to the present invention. As shown in the figure, a displacement sensor 1A according to a modified example of the present invention includes a light projecting unit 3 that emits light toward a measurement object 2 and a light from the light projecting unit 3 that is collected toward the measurement object 2. At least an irradiating unit 4 that irradiates and irradiates, a first light receiving unit 5 that collects and receives the light irradiated and reflected on the measurement object 2, and a second light receiving unit 17 that normalizes the amount of reflected light It is comprised.

  As shown in the figure, the second light receiving unit 17 includes a second half mirror 18, a fourth lens 19, and a second light receiving element 20. The second half mirror 18 is disposed between the first lens 7 and the first half mirror 8 of the light projecting unit 3.

  In the optical system of the displacement sensor 1 </ b> A according to the present embodiment, each component is arranged so that the optical axis of the fourth lens 19 and the optical axis of the second light receiving element 20 are aligned with each other. In addition, the second half mirror 18 so that the optical axis 16 of the light projecting unit 3 and the optical axis 21 of the second light receiving unit 17 (the optical axes of the fourth lens 19 and the second light receiving element 20) are orthogonal to each other. Each component of the 2nd light-receiving part 17 is arrange | positioned through. In FIG. 4, the optical axes 14, 15, 16, and 21 are indicated by alternate long and short dash lines.

  Thus, the measurement accuracy can be further improved by further including the second light receiving unit 17 in the optical system of the displacement sensor 1A. That is, since the second light receiving unit 17 can receive the light amount of the reflected light reflected by the measurement object 2, the light amount can be normalized. More specifically, since the light amount of the first light receiving element 12 can be normalized using the light amount of the second light receiving element 20 as a reference, it is converted into a distance from a change in the amount of received light regardless of the light amount of the light source 6. The displacement of the measurement object 2 can be measured.

  Next, the principle of measuring the displacement of the measurement object 2 by the displacement sensor 1A shown in FIG. 4 will be described.

  First, light emitted from the light source 6 of the light projecting unit 3 passes through the first lens 7 and is collimated to become substantially parallel light, which is irradiated onto the first half mirror 8. Then, the light enters the irradiation unit 4.

  In the irradiation unit 4, the light emitted from the light projecting unit 3 and applied to the first half mirror 8 is changed in its optical path by the first half mirror 8, passes through the second lens 9, and is measured. Irradiated to the surface. In the embodiment shown in FIG. 4, since the light that has been made parallel by the first lens 7 is incident on the second lens 9, the measurement light (light irradiated on the measurement object 2 from the light source) is measured. The light is collected on the object 2.

  This irradiation light is reflected on the measurement object 2 and becomes reflected light. Then, the reflected light is incident again on the second lens 9 and collimated to become almost parallel light. Of the reflected light that has become the parallel light, the light that has passed through the first half mirror 8 enters the first light receiving unit 5.

  In the first light receiving unit 5, the reflected light passes through the hole 13 of the slit plate 10 and enters the third lens 11, and then forms an image on the first light receiving element 12. At this time, since the reflected light made parallel by the second lens 9 is incident on the third lens 11, the reflected light is condensed on the first light receiving element 12 to form an image.

  At this time, as described based on FIG. 8, in the case of FIG. (A3), that is, when the measurement object 2 is not displaced, as shown in black in FIG. (B3), the light receiving surface of the first light receiving element 12 The amount of received light is maximized, and a focused spot image is obtained. On the other hand, as shown in FIGS. (A1) and (A2), when the measurement object 2 is displaced, the spot image of the reflected light formed on the light receiving surface of the first light receiving element 12 is as shown in FIG. As shown in gray in B2), since the amount of received light decreases, the spot image becomes blurred.

  Of the reflected light, the light reflected by the first half mirror 8 enters the second light receiving unit 17. More specifically, first, the light reflected by the first half mirror 8 in the reflected light is changed in its optical path by the first half mirror 8 so as to coincide with the optical axis 16 of the light projecting unit 3. become. Thereafter, the optical path is changed again by the second half mirror 18 so as to be orthogonal to the optical axis 16 of the light projecting unit 3, and the light enters the second light receiving unit 17. In the embodiment shown in FIG. 4, since the light entering the second light receiving unit 17 is parallel light, the reflected light reflected by the second half mirror 18 and passing through the fourth lens 19 is on the second light receiving element 20. Condensed to form an image.

  As described above, the second light receiving unit 17 measures the light amount of the reflected light reflected by the measurement object 2 and normalizes the light amount measured by the first light receiving element 12, so that it does not depend on the light amount of the light source 6. Further, the displacement of the measurement object 2 can be measured by converting the amount of change in the light amount into a distance.

  Therefore, the displacement of the measuring object 2 can be measured with high accuracy even with a small device without having a reciprocating lens.

  Next, another modified example of the displacement sensor according to the present invention will be shown. FIG. 5 shows an optical system of a displacement sensor 1B according to another modification of the present invention. The optical system shown in FIG. 5 is the same as the optical system shown in FIG. 1 except that the diaphragm plate 22 is provided in the first light receiving unit 5 of the optical system shown in FIG. Therefore, the same components as those in FIG.

  That is, as shown in FIG. 5, the displacement sensor 1 </ b> B according to the present invention directs light from the light projecting unit 3 that emits light toward the measurement target 2 and the light from the light projecting unit 3 toward the measurement target 2. The first light receiving unit 5 includes at least an irradiation unit 4 that collects and irradiates light, and a first light receiving unit 5 that collects and receives the light irradiated and reflected on the measurement object 2. A diaphragm plate 22 is provided between the third lens 11 and the first light receiving element 12.

  FIG. 6 shows a plan view of the diaphragm plate 22. The opening 23 provided in the aperture plate 22 is preferably circular as shown in the figure, but is not limited thereto. Similarly to the slit plate 10, the diaphragm plate 22 is also made of a material that does not transmit light, such as a black plastic plate.

  Thus, the 1st light-receiving part 5 is comprised including the slit board 10, the 3rd lens 11, the aperture plate 22, and the 1st light receiving element 12, and the aperture plate 22 is comprised with the 3rd lens 11 and 1st. By providing it between the light receiving element 12, unnecessary light such as disturbance light can be blocked and only the measurement target light can be irradiated onto the first light receiving element 12.

  Next, the principle of measuring the displacement of the measurement object 2 by the displacement sensor 1B shown in FIG. 5 will be described.

  First, in the light projecting unit 3, the light emitted from the light source 6 passes through the first lens 7, is collimated to be substantially parallel light, and is irradiated onto the first half mirror 8. Then, this light enters the irradiation unit 4.

  In the irradiation unit 4, the light irradiated to the first half mirror 8 by the light projecting unit 3 is changed in its optical path by the first half mirror 8, passes through the second lens 9, and reaches the surface of the measurement object 2. Irradiated. In the embodiment shown in FIG. 5, since the light that has been made parallel by the first lens 8 is incident on the second lens 9, the measurement light (light irradiated on the measurement object 2 from the light source) is measured. The light is collected on the object 2.

  This irradiation light is reflected on the measurement object 2 and becomes reflected light. Then, the reflected light is incident again on the second lens 9 and collimated to become almost parallel light. The reflected light that has become the parallel light passes through the first half mirror 8 and enters the first light receiving unit 5.

  In the first light receiving unit 5, the reflected light passes through the hole 13 of the slit plate 10 and enters the third lens 11, then passes through the opening 23 of the diaphragm plate 22, and forms an image on the light receiving surface of the first light receiving element 12. To do. At this time, since the reflected light made parallel by the second lens 9 is incident on the third lens 11, the reflected light is condensed on the first light receiving element 12 to form an image. Note that the imaging state on the light receiving surface of the first light receiving element 12 at this time is as described above with reference to FIG.

  Further, FIG. 7 shows an optical system of a displacement sensor 1C according to still another modified example of the present invention. The displacement sensor 1C shown in FIG. 7 is the same as the displacement sensor 1A shown in FIG. 4 except that the diaphragm plate 22 is provided in the first light receiving portion 5 of the optical system of the displacement sensor 1A shown in FIG. is there. Therefore, the same components as those in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 7, the displacement sensor 1 </ b> C according to the modified example of the present invention directs light from the light projecting unit 3 that emits light toward the measurement target 2 and the light from the light projecting unit 3 to the measurement target 2. An irradiation unit 4 that collects and irradiates the light, a first light receiving unit 5 that collects and receives the light irradiated and reflected on the measurement object 2, and a second light receiving unit 17 that normalizes the amount of reflected light. At least.

  As shown in the drawing, the light projecting unit 3 includes a light source unit 6 and a first half mirror 8, and the irradiation unit 4 includes a first half mirror 8 and a second lens 9. The first light receiving unit 5 includes a slit plate 10, a third lens 11, a diaphragm plate 22, and a first light receiving element 12, and the second light receiving unit 17 includes The second half mirror 18, the fourth lens 19, and the second light receiving element 20 are provided. The second half mirror is disposed between the first lens of the light projecting unit and the first half mirror.

  As shown in FIG. 7, the optical system of the displacement sensor 1C according to the present invention includes the irradiation unit 4 and the first optical unit 14 so that the optical axis 14 of the irradiation unit 4 and the optical axis 15 of the first light receiving unit 5 coincide. Each component of the light receiving unit 5 is arranged. Further, the optical axis 16 of the light projecting unit 3 is disposed via the first half mirror 8 so as to be orthogonal to the optical axis 14 of the irradiation unit 4 and the optical axis 15 of the first light receiving unit 5. Further, in addition to this, each component of the second light receiving unit 17 is interposed via the second half mirror 18 so that the optical axis 16 of the light projecting unit 3 and the optical axis 21 of the second light receiving unit 17 are orthogonal to each other. Has been placed. In FIG. 7, the optical axes 14, 15.16, and 21 are indicated by alternate long and short dash lines.

  As described above, the displacement sensor 1 </ b> C includes the optical system in which the first light receiving unit 5 and the second light receiving unit 17 are configured, so that the measurement accuracy can be further improved. That is, when the reflected light passes through the diaphragm plate 22 in the first light receiving unit 5, only the measurement target light can be irradiated onto the first light receiving element 12, and the second light receiving unit 17 can measure the measurement target object. Since the reflected light amount reflected by 2 can be received, the light amount can be normalized, and the change in the light amount can be measured regardless of the light amount of the light source 6.

  Next, the principle of measuring the displacement of the measurement object 2 by the displacement sensor 1C shown in FIG. 7 will be described.

  First, light emitted from the light source 6 of the light projecting unit 3 passes through the first lens 7 and is collimated to become substantially parallel light, which is irradiated onto the first half mirror 8. Then, the light enters the irradiation unit 4.

  In the irradiation unit 4, the light emitted from the light projecting unit 3 and applied to the first half mirror 8 is changed in its optical path by the first half mirror 8, passes through the second lens 9, and is measured. Irradiated to the surface. In the embodiment shown in FIG. 7, since the light that has been made parallel by the first lens 7 is incident on the second lens 9, the measurement light (light irradiated onto the measurement object 2 from the light source 6) is The light is condensed on the measurement object 2.

  This irradiation light is reflected on the measurement object 2 and becomes reflected light. Then, the reflected light is incident again on the second lens 9 and collimated to become almost parallel light. Of the reflected light that has become the parallel light, the light that has passed through the first half mirror 8 enters the first light receiving unit 5.

  In the first light receiving unit 5, the reflected light passes through the hole 13 of the slit plate 10 and enters the third lens 11, and then passes through the opening 23 of the diaphragm plate 22 and forms an image on the first light receiving element 12. At this time, since the reflected light made parallel by the second lens 9 is incident on the third lens 11, the reflected light is condensed on the first light receiving element 12 to form an image. Note that the imaging state on the light receiving surface of the first light receiving element 12 at this time is as described above with reference to FIG.

  Of the reflected light, the light reflected by the first half mirror 8 enters the second light receiving unit 17. More specifically, first, the light reflected by the first half mirror 8 in the reflected light is changed in its optical path by the first half mirror 8 so as to coincide with the optical axis 16 of the light projecting unit 3. become. Thereafter, the optical path is changed again by the second half mirror 18 so as to be orthogonal to the optical axis 16 of the light projecting unit 3, and the light enters the second light receiving unit 17. In the embodiment shown in FIG. 7, since the light entering the second light receiving unit 17 is parallel light, the reflected light reflected by the second half mirror 18 and passing through the fourth lens 19 is received by the second light receiving element 20. Focus on the surface to form an image.

  In this way, the second light receiving unit 17 measures the amount of reflected light reflected by the measurement object 2 and normalizes the amount of light measured by the first light receiving unit 5, thereby converting the amount of change in the light amount into a distance. The displacement of the measurement object 2 can be measured.

  Therefore, the displacement of the measurement object can be measured with high accuracy even with a small device without including a reciprocating lens.

As described above, according to the displacement sensors 1, 1 </ b> A, 1 </ b> B, and 1 </ b> C according to the present invention, the displacement of the measurement object can be measured with high accuracy without including a reciprocating lens. That is, the displacement sensor according to the present invention can detect displacement with high accuracy even if the displacement sensor is downsized.

1, 1A, 1B, 1C Displacement sensor 2 Measurement object 3 Projection unit 4 Irradiation unit 5 First light reception unit 6 Light sources 7, 9, 11, 19 First to fourth lenses 8, 18 Half mirror 10 Slit plate 12, 20 Light receiving element 14, 15, 16, 21 Optical axis 17 Second light receiving portion 22 Aperture plate

Claims (2)

A light projecting unit having a light source unit that emits light;
An irradiation unit that collects and irradiates the light emitted from the light source unit toward the measurement object;
A displacement sensor including an optical system including a first light receiving unit that collects and receives the light irradiated and reflected by the measurement object;
The light projecting unit includes the light source unit, a first lens, and a first half mirror,
The irradiation unit includes the first half mirror and a second lens,
The first light receiving unit includes the first half mirror and at least four holes, and the four holes are respectively a slit plate disposed on the xy axis, a third lens, and a first light receiving element. Comprising
The irradiation unit and the first light receiving unit are arranged so that an optical axis of the irradiation unit and an optical axis of the first light receiving unit coincide with each other,
The displacement is characterized in that the light projecting unit is disposed via the first half mirror so that the optical axis of the light projecting unit intersects the optical axis of the irradiation unit and the first light receiving unit perpendicularly. Sensor.   A second light receiving part is provided between the first lens of the light projecting part and the first half mirror via a second half mirror, and the second light receiving part has a fourth lens and a second light receiving element. The displacement sensor according to claim 1.

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