JP2001201315A - Displacement sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement sensor capable of improving noise resistance, decreasing the number of part items so as to reduce the size, and reducing the temperature dependency. SOLUTION: A mover K is constituted by forming a moving scale S1 on a movable side optical angle converting lens 12, fixed scales S2, S3 are formed on a first and second fixed side optical angle converting lenses 10, 11, and the moving scale S1 and the fixed scales S2, S3 are made opposite to each other to constitute a sensor length measuring beam scale S. Projecting and photo detecting elements 48, 49A, 49B are disposed outside the sensor main body 4, light emitted by the projecting element 48 is guided to the moving scale S1 side through a projecting optical fiber 45 by the movable side optical angle converting lens 12 and transmitted through the fixed scales S2, S3, and the transmitted light is guided to photo detecting optical fibers 46, 47 by the fixed side optical angle converting lenses S2, S3 and detected by the photo detecting elements 49A, 49B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact-type and digital-type displacement sensor using an optical fiber.

[0002]

2. Description of the Related Art Conventional displacement sensors include a differential transformer type analog displacement sensor, a digital displacement sensor with a built-in light emitting / receiving element, and a digital displacement sensor with a built-in mirror.

[0003] A differential transformer type analog displacement sensor has a linear bush 9 in a housing 90 as shown in FIG.
1 and first and second coils 93 and 94, and a movable shaft 95 and a movable shaft 95
A movable portion 97 having a core member 96 connected to the first and second coils 9 and 9 is provided so as to be movable in the axial direction of a housing 90 via a linear bush 91.
A spring member (not shown) provided in the housing 90 by forming the differential transformer 92 by inserting the bobbin 99 into the bobbin 99 of the third or fourth 94.
The movable part 97 is urged to protrude the distal end of the movable shaft 95 out of the housing 90, and a contact 98 is provided on the projected part of the movable shaft 95.

When the displacement sensor is set at a predetermined position and an alternating current is supplied, the first and second coils 9
A current flows through 3, 94 by electromagnetic induction. Core member 9
When 6 is equally straddling (at the center) the first and second coils 93 and 94, the first and second coils 93 and 9
4 have the same absolute value.

When the object to be detected (not shown) is displaced and interferes with the contact 98 of the displacement sensor, and the movable portion 97 is pushed in against the spring member, the core member 96 of the movable portion 97 is moved to the differential transformer 92. Of the bobbin 99 is moved backward from the center of the bobbin 99 and is largely inserted into the second coil 94 side. Therefore, the voltage induced in the second coil 94 is higher, and the output voltage changes in proportion to the amount of movement of the core member 96. The displacement of the object is detected by detecting the amount of change in the output voltage.

A digital displacement sensor with a built-in light emitting / receiving element is provided with a linear bush 101 and transmission type photoelectric detecting elements (light receiving / emitting elements) 102 and 103 in a housing 100 as shown in FIG. Within
A movable shaft 104 and a movable scale 105 connected to the movable shaft 104 are provided so as to be movable via a linear bush 101, and the movable scale 105 and the fixed scale 107 are connected to a transmission-type photoelectric detection element (light receiving / emitting element) 10.
2 and 103, the movable shaft 104 is urged by a spring member (not shown) provided in the housing 100, and the distal end of the movable shaft 104 is projected out of the housing 100. Probe 106
Is provided.

When the probe 106 detects the displacement of the object (not shown) and the movable shaft 104 moves against the spring member by a movement amount corresponding to the displacement amount, the movable scale 105 also moves. It moves by the same amount as the movement amount of the shaft 104.

Since the amount of transmitted light between the transmissive photoelectric detecting elements (light receiving and emitting elements) 102 and 103 changes due to the movement of the movable scale 105, the displacement of the object is measured by detecting the change in the amount of transmitted light. .

The digital displacement sensor with a built-in mirror has a fixed scale 112 in a housing 110 and mirrors 113 and 114 interposed between the fixed scale 112 as shown in FIG.
A movable shaft 115 is provided so as to be movable via a stem 111 therein, and a movable scale 11 is attached to the movable shaft 115.
6 and the movable scale 115 is fixed to the fixed scale 112.
The movable shaft 115 is urged by a spring member (not shown) provided in the housing 110 to project the tip end of the movable shaft 115 out of the housing 110, and the probe 116 is provided on the projected portion of the movable shaft 115. Configuration.

The light emitted from the light projecting optical fiber 117 is reflected by the mirror 113, passes through the slits of the movable scale 115 and the fixed scale 112, and the transmitted light is reflected by the mirror 114. The light enters the light receiving optical fiber 118, and the amount of transmitted light is detected by a light receiving element (not shown).

When the probe 116 senses the displacement of the object to be detected (not shown) and the movable shaft 115 moves against the spring member by a movement amount corresponding to the displacement amount, the movable scale 116 also moves. It moves by the same amount as the movement amount of the shaft 115. Since the amount of transmitted light changes due to the movement of the moving scale 115, the displacement of the detected object is measured by detecting the change in the amount of transmitted light.

[0012]

However, in the above-described conventional differential transformer type analog displacement sensor, linearity and accuracy are limited due to the analog system, and noise immunity is not ensured. It was difficult. In addition, it has been difficult to achieve both a long stroke and high precision, and the number of components is large, and there is a limit to miniaturization. Further, when a plurality of sensors are attached in close contact, there is a problem that magnetic interference occurs.

In the above-described conventional digital displacement sensor with a built-in light-emitting / light-receiving element, the transmission-type photoelectric detection elements (light-receiving / light-emitting elements) 102 and 103 are built in the housing 100. Type photoelectric detection element 102,
Since it is necessary to incorporate a substrate on which the semiconductor device 103 is mounted, there is a limit to miniaturization, and the number of components is increased, which makes it difficult to reduce costs. Also, since a minute electric signal passes through the cable between the amplifier and the sensor, it is susceptible to electromagnetic noise, and it is difficult to manage and adjust variations in the characteristics of electronic components and dimensional accuracy of mechanical components. ,
In addition, there is a problem that it is difficult to improve the temperature characteristics of the sensor due to the temperature dependency of the electronic component.

In the above-described conventional digital displacement sensor with a built-in mirror, the mirrors 113 and 114 are built in the housing 110, so that the number of parts is large, and it is difficult to adjust the angles of the mirrors 113 and 114. And
A high degree of assembly accuracy is required, such as fixing the light emitting optical fiber 117 and the light receiving optical fiber 118, and positioning the mirrors 113 and 114.
If the angle of 3, 114 is deviated, there is a problem in that the reliability is low such that the displacement detection function of the sensor is seriously hindered.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is not only to solve the above-mentioned problems but also to improve noise resistance. It is another object of the present invention to provide a displacement sensor capable of reducing the number of parts, enabling downsizing, and reducing temperature dependency.

[0016]

In order to achieve the above object, a displacement sensor according to the present invention comprises a fixed scale in which a large number of fixed slits are arranged in parallel at a predetermined pitch on a sensor body, and an object to be detected. And a movable body that senses the displacement of the movable body and moves in accordance with the amount of the displacement. The movable body is provided with a movable scale in which a large number of movable slits are arranged in parallel at a predetermined pitch. And a displacement sensor for detecting a change in the amount of transmitted light transmitted through the fixed slit and the fixed slit, wherein the sensor body has a fixed-side light angle conversion lens and a movable-side light angle conversion lens, A moving scale is formed on the lens, the fixed scale is formed on the fixed-side optical angle conversion lens, and the moving scale and the fixed scale are opposed to each other to form a sensor measuring optical scale. An optical element is arranged, and the light emitted from the light emitting element is guided to the moving scale side by the movable-side optical angle conversion lens via the optical fiber for light transmission, and is transmitted through the fixed scale. The light is guided to a light receiving optical fiber side by a lens and received by a light receiving element.

With this configuration, the light from the light projecting element disposed outside the sensor main body is conveyed through the light projecting optical fiber and input to the movable-side light angle conversion lens, where it is moved to the movable slit of the movable scale and the fixed scale. Light transmitted through the fixed slit, input to the fixed-side light angle conversion lens, and output from the fixed-side light angle conversion lens is received by the light receiving element via the light receiving side optical fiber.

When the movable body senses the displacement of the object to be detected and moves by a movement amount corresponding to the displacement amount, the moving scale moves by the movement of the movable-side optical angle conversion lens of the movable body, The movement of the moving scale changes the amount of light transmitted through the movable slit and the fixed slit. This change in the amount of transmitted light is detected by the light receiving element, and the number of times of transmission / shielding is counted by a counter and converted into displacement.

As described above, since the projection and light receiving elements are provided outside the sensor body and the projection and reception side optical fibers are used to project and receive light on the sensor length measuring optical scale composed of the moving slit and the fixed scale, noise resistance is improved. In addition, since the sensor measurement optical scale is configured by providing the movable scale on the movable-side optical angle conversion lens and the fixed scale on the fixed-side optical angle conversion lens, the number of parts is reduced. The temperature dependency can be reduced because the sensor body can be reduced and the electronic device can be reduced in size.

According to another aspect of the present invention, there is provided a displacement sensor according to the present invention, wherein the fixed-side light angle conversion lens is a combination of a plurality of fixed-side light angle conversion lenses. A fixed scale is formed on each of the plurality of fixed-side light angle conversion lenses, the pitch of adjacent fixed scales is shifted by a predetermined amount, and the respective light receiving portions are provided on the output sides of the plurality of fixed-side light angle conversion lenses. In addition to disposing optical fibers for light, each light receiving element is arranged on the output side of the optical fiber for receiving light, and the light propagating in the optical fiber for light projection is divided into a plurality of light beams, and these light beams are separated into the light angles on the movable side. The light is guided to the moving scale side by the conversion lens, each spectrum is transmitted to each of the fixed scales, and the transmitted light is guided to the light receiving optical fiber side by a plurality of fixed-side light angle conversion lenses. In which it was to receive.

With this configuration, not only can the same operation and effect as the above-described displacement sensor according to the present invention be exerted, but also the light propagating in the light-projecting optical fiber is split into a plurality of light beams, and these light beams are separated into the movable side. The light angle conversion lens guides the light to the moving scale side, transmits each spectrum to each of the fixed scales, guides the transmitted light to the light receiving optical fiber side with a plurality of fixed side light angle conversion lenses, and receives the light with the light receiving element can do.

Further, for example, by disposing the fixed scales so that the positions of the fixed slits of adjacent fixed scales are shifted by p / 4, the phases of the output signals from one and the other light receiving elements are shifted by π / 2. Since the sum of the output signals from the one and the other light receiving elements changes every p / 4, the resolution of the pitch is increased to p / 4. Further, the moving direction of the movable body can be determined by using the phase difference between the output signals from the one and the other light receiving elements.

According to another aspect of the present invention, there is provided a displacement sensor according to the present invention, wherein the movable scale is provided with a plurality of moving scales in the longitudinal direction of one surface of the movable-side optical angle conversion lens. The fixed scale is formed by forming a large number of movable slits by forming the concave and convex portions, and by forming a large number of concave and convex portions in the longitudinal direction of one surface of the fixed-side optical angle conversion lens by forming the fixed scale. Things.

Further, a light shielding film is formed on one of the concave portion and the convex portion of the concave and convex portion to form a large number of movable slits, and a light shielding film is formed on one of the concave portion and the convex portion of the concave and convex portion. To form a large number of fixed slits.

With this configuration, not only can the same effect as the above-described displacement sensor according to the present invention be exerted, but also, in particular, the moving scale is formed by forming a large number of uneven portions in the longitudinal direction of one surface of the movable-side optical angle conversion lens. (Or by forming a light blocking film on either the concave part or the convex part of the concave and convex part)
A fixed scale is formed by forming a large number of movable slits, and a fixed scale is formed with a large number of uneven portions in the longitudinal direction of one surface of the fixed-side optical angle conversion lens (or a light is applied to either the concave portion or the convex portion of the uneven portion). Since a large number of fixed slits can be formed (by forming a blocking film), the number of parts can be reduced and the size can be further reduced.

In order to achieve the above object, a displacement sensor according to the present invention comprises a fixed scale having a large number of fixed slits arranged in parallel at a predetermined pitch on a sensor body;
A movable body that senses the displacement of the object to be detected and moves in accordance with the amount of displacement; a movable scale provided with a plurality of movable slits arranged in parallel at a predetermined pitch on the movable body; A displacement sensor that detects a change in the amount of transmitted light that passes through the movable slit and the fixed slit. The moving scale and the fixed scale are opposed to each other to form a sensor measuring optical scale. And a light projecting side mirror is formed at the end of the light emitting optical fiber that conveys the light emitted from the light emitting element, and the light is received at the end of the light receiving optical fiber that guides the received light to the light receiving element. Form the side mirror part, insert the respective ends of the optical fiber for light emission and the optical fiber for light reception into the sensor body, and connect the light-emitting side mirror part and the light reception side mirror part to the sensor length measuring optical scale. Sandwich It is intended.

The light emitting side mirror may be formed by polishing the end of the light emitting optical fiber obliquely with respect to the traveling path of light, or the light receiving side mirror may be formed by polishing the light receiving side light. The end portion of the fiber may be formed by polishing in such a manner that the end portion of the fiber is inclined in the opposite direction to the mirror portion on the light emitting side. The light-emitting side mirror is formed by forming a notch at the end of the light-emitting optical fiber, polishing and plating the surface of the notch, and the light-receiving side mirror is formed on the light-receiving side. Form a notch at the end of the optical fiber,
The surface of the notch may be polished and plated.

The light emitting optical fiber is held by the light emitting optical fiber holder, and the light receiving side optical fiber is held by the light receiving side optical fiber holder. Each has an opening,
A path of light reflected by the light-emitting side mirror and incident on the light-receiving side mirror may be formed.

With this configuration, light from the light projecting element disposed outside the sensor main body is conveyed in the light projecting optical fiber and reflected by the light projecting side mirror section. The light passes through the fixed slit of the fixed scale, is taken into the light receiving optical fiber from the light receiving side mirror of the light receiving optical fiber, and is received by the light receiving element via the light receiving side optical fiber.

When the movable body senses the displacement of the object to be detected and moves by a movement amount corresponding to the displacement amount, the moving scale of the movable body moves, and the movement of the moving scale causes the movable slit to move. The amount of transmitted light that passes through the fixed slit changes. This change in the amount of transmitted light is detected by the light receiving element, and the number of times of transmission / shielding is counted by a counter, and can be converted into displacement.

As described above, since the projection and light receiving elements are provided outside the sensor main body, and the projection and light reception side optical fibers are used to project and receive light on the sensor measuring optical scale composed of the moving slit and the fixed scale, noise immunity is improved. As a separate part to form a light-emitting side mirror at the end of the light-emitting optical fiber and to form a light-receiving side mirror at the end of the light-receiving optical fiber. No mirror is required, the number of parts can be reduced, and the size can be reduced.

In order to achieve the above object, the displacement sensor according to the present invention is the displacement sensor according to the present invention described above, wherein a plurality of fixed scales are used to adjust the pitch between adjacent fixed scales. The end portions of the projecting and receiving optical fibers corresponding to the combination of the movable scale and the individual fixed scales are inserted into the sensor body by being shifted by a predetermined amount.

With this configuration, not only the same operation and effect as the above-described displacement sensor according to the present invention can be obtained, but also, for example, the position of the fixed slit of the adjacent fixed scale is p /
By arranging the fixed scale so as to shift by four, the phases of the output signals from one and the other light receiving elements are shifted by π / 2, and the sum of the output signals from the one and the other light receiving elements is p / 4 Therefore, the pitch resolution is increased to p / 4. Further, the moving direction of the movable body can be determined by using the phase difference between the output signals from the one and the other light receiving elements.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

An embodiment of the displacement sensor according to the present invention is shown in FIGS.

(Embodiment 1) A displacement sensor according to the present invention includes a case 3 having a case body 1 having an opening 1A on a side surface, and a lid 2 covering the opening 1A of the case body 1. Sensor body 4 housed inside case 3
It consists of: And the front part 1 of the case body 1
B is provided with a shaft hole 5.
The rear surface portion 1C is provided with a light emitting side optical fiber mounting hole 6 and light receiving side optical fiber mounting holes 7, 8. Note that 1a, 1
b is a mounting hole.

The sensor body 4 has a fiber holder 9, first and second fixed-side light angle conversion lenses 10, 11, a movable side light angle conversion lens 12, a movable shaft 13, and a spring member 27. are doing. The fiber holder 9 includes a concave rod holding portion 14, a spectral lens 15, and a light emitting side optical fiber attaching portion 1 provided on the back side of the spectral lens 15.
6 and the light receiving side optical fiber mounting portions 17a and 17b are provided.

The rod holder 1 of the fiber holder 9
A base end of a rod 27A is fitted to 4 and a spring member 27 is provided in the lot 27A. The base end of the spring member 27 is fitted to the rod holding portion 14.

The movable-side optical angle conversion lens 12 includes a parabolic mirror 18, an input side 19 opposed to the parabolic mirror 18, and an output side 2 perpendicular to the input side 19.
The input side surface portion 19 has an arc surface portion 21. The output side surface portion 20 has a large number of concave and convex portions 22 formed in the longitudinal direction thereof. The concave portions 22a and the convex portions 22b of the concave and convex portions 22 are formed in an arc shape as shown in FIG. In this case, the light n is transmitted through the concave portion 22a, and the light n is diffused and blocked by the convex portion 22b, so that the plurality of movable slits 26 are arranged in parallel at a predetermined pitch p and move. This constitutes a scale S1.

The light blocking film 22b is formed on the bottom surface of the concave portion 22a of the concave / convex portion 22 by plating with Cr or the like as shown in FIG. 6B, and the concave portion is formed as shown in FIG. A movable scale S1 in which a plurality of movable slits 26 are arranged in parallel at a predetermined pitch p by forming the movable slits 26 between the convex portions 23 between the 22 may be configured. Note that the light blocking film may be formed by plating Cr or the like on the top of the protrusion 23, and the recess 22 a may be formed as the movable slit 26.

At the end of the parabolic mirror 18 of the movable-side optical angle conversion lens 12, a base of a movable shaft 13 is attached in parallel with the output side surface 20. A stopper portion 24 is formed close to the side. In addition, the movable-side optical angle conversion lens 12 includes:
An insertion hole 25 is provided from the input side surface portion 19 toward the movable shaft 13. And the movable shaft 1
The movable body K is composed of the movable-side optical angle conversion lens 12 and the movable scale S1.

Further, the first fixed-side light angle conversion lens 10
Has a parabolic mirror surface portion 28, an input side surface portion 29 facing the parabolic mirror surface portion 28, and an output side surface portion 30, and the corners formed by the input side surface portion 29 and the output side surface portion 30 are gathered. An optical lens 31 is formed. The input side surface portion 29 is formed with a large number of uneven portions 32 at a predetermined pitch in the longitudinal direction, and these uneven portions 32 are formed in an arc shape as shown in FIG. Recess 2
2a, the light n is transmitted therethrough, and the light n is diffused and shielded from the projections 22b, so that a number of movable slits 36 are arranged in parallel at a predetermined pitch p to form one fixed scale S
2. The light blocking film 33b is formed on the bottom surface of the concave portion 32a of the concave / convex portion 32 by plating with Cr or the like as shown in (3) of FIG. The fixed slits 36 may be formed by the protrusions 33, and one fixed scale S2 may be formed by arranging a large number of fixed slits 36 in parallel at a predetermined pitch p. Note that the light blocking film may be formed by plating Cr or the like on the top of the protrusion 33, and the recess 32 a may be formed as the fixed slit 36.

Further, the second fixed-side optical angle conversion lens 11
Has a parabolic mirror portion 38, an input side surface portion 39 facing the parabolic mirror portion 38, and an output side surface portion 40. The corners formed by the input side surface portion 39 and the output side surface portion 40 are gathered. An optical lens 41 is formed. The input side surface portion 39 is formed with a large number of uneven portions 42 at a predetermined pitch in the longitudinal direction, and these uneven portions 42 are formed in an arc shape as shown in FIG. Recess 2
2a, the light n is transmitted, and the convex portion 22b diffuses the light n to block the light. Thus, the plurality of fixed slits 44 are arranged in parallel at a predetermined pitch p and the other fixed scale S
3.

Also, as shown in FIG. 6C, a light shielding film 42b is formed on the bottom surface of the concave portion 42a of the concave / convex portion 42 by plating with Cr or the like, as shown in FIG.
To form the fixed slit 44, and the many fixed slits 44 are arranged in parallel at a predetermined pitch p to form the other fixed scale S3. Note that the light blocking film may be formed by plating Cr or the like on the top of the projection 43, and the recess 42 a may be formed as the fixed slit 44.

Then, the first fixed-side light angle conversion lens 10
The second fixed-side light angle conversion lens 11 and the second fixed-side light angle conversion lens 11 are fixed to the fiber holder 9 such that their respective side surfaces are aligned. In this case, the fixed slits 36 and 46 of the one fixed scale S2 and the other fixed scale S3 are shifted by p / 4.

The movable optical angle conversion lens 12 has a rod 27A slidably inserted into the insertion hole 25 thereof.
The spring member 27 is held by the rod 27A.
Is in contact with the end side of the input side surface portion 19.

The sensor main body 4 configured as described above is housed inside the case 3. In this case, the movable shaft 13 penetrates through the shaft hole 5 of the front surface portion 1B of the case body 1 and protrudes outward, and the movable-side optical angle conversion lens 12 has a spring interposed between it and the fiber holder 9. The movable shaft 13 is pressed by the urging force of the member 27.
Is in contact with the inner surface of the front portion 1B of the case body 1.

In this state, the output side surface portion 20 of the movable side light angle conversion lens 12 is opposed to the input side surface portions 29, 39 of the first and second fixed side light angle conversion lenses 10, 11. The movable scale S1 faces one and the other fixed scales S2 and S3, and these constitute the sensor length measuring light scale S.

The end of the light emitting side optical fiber 45 is attached to the light emitting side optical fiber mounting hole 6 on the rear surface 1C of the case body 1, and one light receiving side optical fiber mounting hole 7 is provided.
The front end of one light receiving optical fiber 46 is attached to the other end, and the front end of the other light receiving optical fiber 47 is attached to the other light receiving optical fiber mounting hole 8. The light projecting side optical fiber 45 projects light from the light projecting element 48, and the light receiving elements 49A and 49B are provided on the terminal side of one and the other light receiving side optical fibers 46 and 47.

Next, the operation of the displacement sensor configured as described above will be described. As shown in FIG. 2, the light beam from the light projecting element 48 is conveyed by the light projecting side optical fiber 45 and enters the spectral lens 15 formed in the fiber holder 9, and the light beam is transmitted by the spectral lens 15 to one light beam And the other light C. One of the light sources is a movable-side light angle conversion lens 1.
2 enters (inputs) the movable-side optical angle conversion lens 12 from the input side surface portion 19, is reflected by the parabolic mirror surface portion 18, and travels in a direction perpendicular to the output side surface portion 20.

This reflected light b ′ exits the output side surface portion 20 and
The light enters the first fixed-side optical angle conversion lens 10 from the input side surface 29 of the first fixed-side optical angle conversion lens 10 and is reflected by the parabolic mirror surface section 28. The reflected light b ″ goes straight to the condenser lens 31, enters one light receiving side optical fiber 46 via the fiber holder 9, and is received by the light receiving element 49A.

The other light beam split by the splitting lens 15 is input to the input side surface portion 19 of the movable-side light angle conversion lens 12.
Is incident on the movable-side optical angle conversion lens 12 from the arcuate surface part 21 of the lens, is reflected by the parabolic mirror part 18, and is output from the output side part 20.
Proceed in the direction perpendicular to.

The reflected light C 'exits the output side surface portion 20 and
The light enters the second fixed-side light-angle conversion lens 11 from the input side surface 39 of the second fixed-side light-angle conversion lens 11 and is reflected by the parabolic mirror surface 38. This reflected light c ″ goes straight to the condenser lens 41, enters the other light receiving side optical fiber 47 via the fiber holder 9, and is received by the light receiving element 49 </ b> B.

In this case, the reflected light b 'is
Pass through the movable slit 26 of the moving scale S1 and the fixed slit 36 of the fixed scale S2.
3 and fixed slit 44.

When the movable shaft 13 senses the displacement of the object to be detected (not shown) and moves by a movement amount corresponding to the displacement amount against the spring member 27, the movable-side light angle conversion lens 12 Also moves by the same amount as the moving amount of the movable shaft 13.

The movable scale S1 is moved by the movement of the movable-side optical angle conversion lens 12, and the movable slit 26 and one and the other fixed slits 36, 4 are moved by the movement of the movable scale S1.
4, the light passing area changes, and the amount of transmitted light changes.
That is, the amount of reflected light b 'transmitted through the sensor measuring light scale S changes, and this change in transmitted light amount is detected by one of the light receiving elements 49A. The amount of light transmitted through S changes, and the change in the amount of transmitted light is detected by the other light receiving element 49B.

Also, as shown in FIG. 5, the first and second fixed slits 36, 44 are shifted by p / 4 so that
Since the fixed-side light angle conversion lens 10 and the second fixed-side light angle conversion lens 11 are arranged, the phases of the output signals from one and the other light receiving elements 49A and 49B are shifted by π / 2. The one and the other light receiving elements 49A,
Since the sum of the output signals from 9B varies every p / 4,
The pitch resolution is increased to p / 4. Further, it is possible to determine the moving direction of the detection target by using the phase difference between the output signals from the one and the other light receiving elements 49A and 49B.

According to the first embodiment of the present invention, the light-receiving elements 48, 49A, and 49B are provided outside the sensor main body 4;
Since the projection and reception side optical fibers 45, 46 and 47 perform projection and reception on the sensor measurement optical scale S, noise resistance can be improved, and the sensor measurement optical scale S
Since the movable scale S1 is provided on the movable-side optical angle conversion lens 12 and the fixed scales S2 and S3 are provided on the first and second fixed-side optical angle conversion lenses 10 and 11, respectively, the number of parts can be reduced and the size can be reduced. In addition, since there is no electronic component in the sensor body 4, the temperature dependency can be reduced.

(Embodiment 2) FIGS. 7 to 14 show a second embodiment of the displacement sensor according to the present invention.

This displacement sensor has a sensor main body 50. The sensor main body 50 has a tubular housing 51 made of stainless steel, and a bush 52 is provided in the housing 51 from the front to the rear thereof. , Linear bearing 53, spring fuser 54, spring guide 55, shaft holder 56, scale holder 5
7, a first fiber holder 58, a second fiber holder 59, and the like.

As shown in FIGS. 10 and 11, a scale holder 57 is connected to the shaft holder 56, and a movable scale 60 is mounted on the scale holder 57. As shown in FIG. 14, the moving scale 60 has a large number of moving slits 61 arranged in parallel at a predetermined pitch p. The shaft holder 56 has a shaft 6.
The shaft 62 is movably held by a linear bearing 53. Shaft 6
A probe guide 63 is provided at the distal end of the probe 2, and a probe 64 is attached to the probe guide 63.
The movable body K-1 is constituted by the shaft 62 and the scale holder 57.

The first fiber holder 58 is a cylindrical body as shown in FIGS. 10 to 12, and has a scale holder insertion portion 65 formed rearward from the distal end face portion 58a of the first fiber holder 58. A fixed scale 66 is provided on one surface 65a of the scale holder insertion portion 65. As shown in FIG. 14, this fixed scale 66 has one scale 66-1 formed by arranging a large number of fixed slits 66a in parallel at a predetermined pitch p and a large number of fixed slits 66b in parallel at a predetermined pitch p. The other scale 66-2 is arranged side by side, and the fixed slits 66a and 66b are shifted by p / 4 from one scale 66-1 and the other scale 66-2.

As shown in FIG. 12, two fiber holding holes 7 are provided at both ends of the first fiber holder 58 with the scale holder insertion portion 65 interposed therebetween.
1a, 71b, 72a and 72b are provided. A spring holder 55 is provided on the distal end surface 58a of the first fiber holder 58.
Is formed with a half-divided scale guide 69.

The scale holder 57 is movably inserted into the scale holder insertion portion 65 via the scale guide 69, and the movable scale 60 is overlapped with the fixed scale 66 at a predetermined interval. It constitutes a length measuring light scale S-1. A spring 70 is interposed between the spring fuser 54 and the shaft holder 56, and the spring 70 is held by a spring guide 55.

As shown in FIGS. 12 and 13, the second fiber holder 59 is composed of two projecting side optical fiber holders 59.
A, 59B and two light receiving side optical fiber holders 59C,
59D. Then, as shown in FIG. 15, openings 59A-1, 59B-1 and 59C- opposed to each other are provided at the leading ends of the light emitting side optical fiber holders 59A and 59B and the light receiving side optical fiber holders 59C and 59D.
1, 59D-1 are provided respectively.

Then, the light emitting side optical fiber holder 59A,
The projecting side optical fibers 73 and 74 are inserted in 59B, and the receiving side optical fibers 75 and 76 are inserted in the receiving side optical fiber holders 59C and 59D. The end portions 73a and 74a of the light emitting side optical fibers 73 and 74 are formed with light emitting side mirror portions 77-1 and 77-2 formed by being polished obliquely with respect to the light traveling path f. The end portions 75a, 76a of the side optical fibers 75, 76 are formed with light receiving side mirror portions 78-1, 78-2 which are polished obliquely in the opposite direction to the light projecting side mirror portions 77-1, 77-2. I have.

The rear part of the first fiber holder 58 is inserted into the front side of the second fiber holder 59,
The terminal portions of the light emitting side optical fiber holders 59A and 59B are as follows:
The end portions of the light receiving side optical fiber holders 59C and 59D are inserted and fixed in fiber holding holes 71a and 71b formed in the distal end surface portion 58a of the first fiber holder 58, respectively. And is fixedly inserted into the fiber holding holes 72a and 72b formed in the holes.

Then, the light-emitting side mirror section 77- provided on the terminal sections 73a, 74a of the light-emitting side optical fibers 73, 74.
1, 77-2, and the light-receiving-side mirror portions 78-1 provided on the terminal portions 75a, 76a of the light-receiving-side optical fibers 75, 76;
78-2 means the openings 59A-1, 59B-1, 59C
The moving scale 66 and the fixed scale 66 are opposed to each other via -1, 59D-1.

That is, the light-emitting side mirror section 77-1 and the light-receiving side mirror section 78-1 are opposed to each other with the movable scale 66 and one fixed scale 66-1 interposed therebetween. The light-receiving side mirror unit 78-2 and the light-receiving side mirror unit 78-2 are opposed to each other with the movable scale 66 and the other fixed scale 66-2 interposed therebetween, and constitute a part of a light traveling path f.

Also, one and the other light emitting fibers 73,
Numeral 74 is for projecting the light from the light projecting elements 81 and 82, and light receiving elements 83 and 84 are provided on the terminal sides of one and the other light receiving fibers 75 and 76, respectively.

Next, the operation of the displacement sensor configured as described above will be described.

As shown in FIG. 8, the light beams d and d ′ from the light projecting elements 81 and 82 are one and the other light projecting side optical fibers 73 and
The light propagates through 74 and reaches the light-emitting side mirror portions 77-1 and 77-2. The light d is reflected by the light-emitting side mirror portion 77-1 of one of the light emitting side optical fibers 73 and moves the movable scale 60. The light passes through the slit 61, passes through the fixed slit 66 a of the fixed scale 66-1, and passes through one of the light receiving optical fibers 75.
The light is reflected by the light-receiving-side mirror section 78-1, and enters the one light-receiving-side optical fiber 75, and is received by the one light-receiving element 83.

The light d ′ that has propagated through the other light emitting side optical fiber 74 is reflected by the light emitting side mirror portion 77-2 of the other light emitting side optical fiber 74, and moves through the moving slit 61 of the moving scale 60. The light passes through the fixed slit 66b of the other fixed scale 66-2, is reflected by the light receiving side mirror portion 78-2 of the other light receiving side optical fiber 76, and is incident on the other light receiving side optical fiber 76, The light is received by the other light receiving element 84.

Then, the probe 64 senses the displacement of the object to be detected (not shown), and when the shaft 62 moves against the spring member 70 by a movement amount corresponding to the displacement amount, the probe 64 is mounted on the scale holder 54. The moved moving scale 60 also moves by the same amount as the moving amount of the shaft 62.

When the movable scale 60 is moved, the movable slit 6 is moved.
1 and the light passing area between the fixed slits 66a and 66b change, and the amount of transmitted light changes. That is, the amount of reflected light that passes through the sensor measurement light scale S-1 changes, and this change in the amount of transmitted light is detected by one of the light-receiving elements 83. The amount of light transmitted through the scale S-1 changes, and the change in the amount of transmitted light is detected by the other light receiving element 84.

As shown in FIG. 14, the fixed slit 66a
Since one fixed scale 66-1 and the other fixed scale 66-2 are arranged so that the position of 66b is shifted by p / 4, the phase of the output signal from one and the other light receiving elements 83 and 84 is π / 2, and the sum of the output signals from one and the other light receiving elements 83 and 84 is p / 4
Therefore, the pitch resolution is increased to p / 4. Further, it is possible to determine the moving direction of the detected object by using the phase difference between the output signals from the one and the other light receiving elements 83 and 84.

As described above, according to the second embodiment of the present invention, light is projected out of the sensor body 50, and the light receiving elements 81, 8
2, 83 and 84, and the projecting and receiving side optical fibers 73 and 7
At 4, 75 and 76, the projection onto the sensor measuring light scale S-1 is performed.
Since light is received, noise resistance can be improved, and the terminal portions 73 of the light projecting optical fibers 73 and 74 can be improved.
a, 74a are formed with light-projecting side mirror portions 77-1, 77-2, and the terminal portions 75 of the light receiving optical fibers 75, 76 are formed.
Since the light-receiving-side mirror portions 78-1 and 78-2 are formed on the a and 76a, a mirror as a separate component is not required, the number of components can be reduced, and the size can be reduced.

The light-emitting side mirror units 77-1, 77-2
Are the terminal portions 75a, 76 of the light emitting optical fibers 75, 76.
a may be formed by polishing and plating the surface of the notch, or the light-receiving-side mirror may be formed by terminating the light-receiving-side optical fibers 78-1 and 78-2. Alternatively, a notch may be formed, and the surface of the notch may be polished and plated.

[0079]

As described above, according to the displacement sensor according to the present invention, the light from the light projecting element disposed outside the sensor main body is conveyed in the light projecting optical fiber and converted to the movable side light angle conversion. Light is input to the lens, passes through the moving slit of the moving scale and the fixed slit of the fixed scale, is input to the fixed-side optical angle conversion lens, and is output from the fixed-side optical angle conversion lens via the receiving-side optical fiber. The light is received by the element.

When the movable body senses the displacement of the object to be detected and moves by a movement amount corresponding to the displacement amount, the movable scale moves by the movement of the movable-side optical angle conversion lens of the movable body, The movement of the moving scale changes the light passing area between the movable slit and the fixed slit, and changes the amount of transmitted light. This change in the amount of transmitted light is detected by the light receiving element, and the number of times of light projection / shielding is counted by a counter, and can be converted into displacement.

As described above, since the light projecting and light receiving elements are provided outside the sensor main body, and the light projecting and light receiving side optical fibers are used for light projecting and light receiving on the sensor length measuring optical scale, noise resistance can be improved. In addition, since the sensor measuring optical scale is provided with a movable scale on the movable-side optical angle conversion lens and a fixed scale on the fixed-side optical angle conversion lens, the number of parts can be reduced and the size can be reduced. In addition, since there is no electronic component in the sensor main body, the temperature dependency can be reduced.

According to the displacement sensor of the present invention,
The light from the light emitting element disposed outside the sensor body is conveyed through the light emitting optical fiber and reflected by the light emitting side mirror formed at the end of the light emitting optical fiber. The light passes through the moving slit of the moving scale and the fixed slit of the fixed scale, is taken into the light receiving optical fiber from the light receiving side mirror formed at the end of the light receiving optical fiber,
The light is received by the light receiving element via the light receiving side optical fiber.

When the movable body senses the displacement of the object to be detected and moves by a movement amount corresponding to the displacement amount, the movable scale of the movable body moves, and the movement of the movable scale causes the movable slit to move. The light passing area with the fixed slit changes, and the amount of transmitted light changes. This change in the amount of transmitted light is detected by the light receiving element, and the number of times of light projection / shielding is counted by a counter, and can be converted into displacement.

As described above, since the light projecting and light receiving elements are provided outside the sensor main body and the light projecting and receiving side optical fibers are used to project and receive light on the sensor length measuring optical scale, noise resistance can be improved. In addition, since the light-emitting side mirror is formed at the end of the light-emitting optical fiber and the light-receiving side mirror is formed at the terminal of the light-receiving optical fiber, a separate mirror is not required. In addition, the number of parts can be reduced, and the size can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a displacement sensor (first embodiment) according to the present invention.

FIG. 2 is a side view of a sensor main body in the displacement sensor.

FIG. 3 is a perspective view of the sensor main body as viewed from the front side.

FIG. 4 is a perspective view of the sensor main body as viewed from the rear side.

FIG. 5 is an explanatory diagram of a configuration of a sensor measurement optical scale.

FIG. 6A is an explanatory view in which a part of a moving and fixed scale is omitted. (2) is a side view in which a part of the moving scale is omitted. (3) is a side view with a part of the fixed scale omitted.

FIG. 7 is a side view of a displacement sensor (Embodiment 2) according to the present invention.

FIG. 8 is a perspective view of the disassembled state of the displacement sensor with a part omitted.

FIG. 9 is a perspective view of the disassembled state of the displacement sensor with a part thereof omitted.

FIG. 10 is a perspective view of a sensor measuring optical scale portion of the displacement sensor.

FIG. 11 is an exploded perspective view of a sensor measurement optical scale portion of the displacement sensor.

FIG. 12 is an exploded perspective view of a fiber holder portion of the displacement sensor.

FIG. 13 is a perspective view of a fiber holder part of the displacement sensor.

FIG. 14 is an explanatory diagram of a configuration of a sensor length measuring optical scale.

FIG. 15 is an explanatory diagram of a configuration of a projecting and light receiving side mirror unit of the displacement sensor.

FIG. 16 is an exploded perspective view of a conventional displacement sensor with a part thereof omitted.

FIG. 17 is a perspective view of another conventional displacement sensor in an exploded state with a part thereof omitted.

FIG. 18 is a sectional view of another conventional displacement sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case main body 2 Lid 3 Case 4 Sensor main body 5 Shaft hole 6 Light emitting side optical fiber mounting hole 7 Light receiving side optical fiber mounting hole 8 Light receiving side optical fiber mounting hole 9 Fiber holder 10 First fixed side light angle Conversion lens 11 Second fixed-side light-angle conversion lens 12 Movable-side light-angle conversion lens 13 Movable shaft 14 Rod holding unit 15 Spectral lens 16 Light-emitting-side optical fiber mounting unit 17a Light-receiving-side optical fiber mounting unit 17b Light-receiving-side optical fiber mounting Part 18 Parabolic mirror part 19 Input side part 20 Output side part 21 Circular surface part 22 Irregular part 22a Concave part 22b Light blocking film 23 Convex part 24 Stopper part 25 Insertion hole 26 Movable slit 27 Spring member 27A Rod 28 Parabolic mirror part 29 Input Side surface portion 30 Output side surface portion 31 Condensing lens 32 Irregularity portion 32a Concave portion 32b Light shielding Film 33 convex portion 36 fixed slit 38 parabolic mirror surface portion 39 input side surface portion 40 output side surface portion 41 condensing lens 42 concave and convex portion 42a concave portion 42b light blocking film 43 convex portion 44 fixed slit 45 light emitting side optical fiber 46 light receiving side optical fiber 47 Light receiving side optical fiber 48 Light emitting element 49A element 49B Light receiving element 50 Sensor main body 51 Housing 52 Bush 53 Linear bearing 54 Spring fuser 55 Spring guide 56 Shaft holder 57 Scale holder 58 First fiber holder 59 Second fiber holder 60 Moving scale 61 Moving Slit 62 Shaft 63 Probe Guide 64 Probe 65 Scale Holder Insert 66 Fixed Scale 66a Fixed Slit 66-1 One Fixed Scale 66-2 The Other Fixed Scale 69 Ruler 70 Spring 73 Projecting side optical fiber 73a Terminal section 74 Projecting side optical fiber 74a Terminal section 75 Receiving side optical fiber 75a Terminal section 76 Receiving side optical fiber 76a Terminal section 77-1 Projecting side mirror section 77-2 Projecting side Side mirror part 78-1 Light receiving side mirror part 78-2 Light receiving side mirror part 79 Notch part 79A surface part 80 Notch part 80A surface part 81 Light emitting element 82 Light emitting element 83 Light receiving element 84 Light receiving element K movable body K-1 movable Body S Sensor measuring light scale S-1 Sensor measuring light scale S1 Movable scale S2 Fixed scale S3 Fixed scale

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2F065 AA02 DD02 DD04 DD11 FF16 GG12 HH15 JJ05 JJ15 LL02 LL04 LL10 LL12 LL19 LL28 LL67 2F069 AA02 AA06 DD26 DD27 DD30 GG07 HH14 MM17 MM26 2F103 BA10 EB02 EB02 EB02 EB33 EC01 EC08 GA01

Claims (9)

[Claims] 1. A fixed scale in which a large number of fixed slits are arranged in parallel at a predetermined pitch in a sensor main body, and a movable body that senses displacement of an object to be detected and moves in accordance with the displacement amount, The movable body is provided with a moving scale in which a large number of moving slits are arranged in parallel at a predetermined pitch, and a displacement sensor that detects a change in the amount of light transmitted through the movable slit and the fixed slit by movement of the moving scale. Wherein the sensor body has a fixed-side light angle conversion lens and a movable-side light angle conversion lens, and the movable body is formed by forming a movable scale on the movable-side light angle conversion lens; Forming the fixed scale on the light angle conversion lens, forming the sensor scale optical scale by opposing the moving scale and the fixed scale, projecting outside the sensor body, arranging a light receiving element, The light emitted from the optical element is guided to the moving scale side by the movable-side light angle conversion lens via the light projecting optical fiber and transmitted through the fixed scale, and the transmitted light is received by the fixed-side light angle conversion lens. A displacement sensor guided to the optical fiber side for use and receiving light by the light receiving element. 2. The fixed-side light angle conversion lens is a combination of a plurality of fixed-side light angle conversion lenses, and the fixed scale is formed on each of the plurality of fixed-side light angle conversion lenses, and the fixed scales are adjacent to each other. The pitch of the fixed scale is displaced by a predetermined amount, and the respective light receiving optical fibers are arranged on the output side of the plurality of fixed side light angle conversion lenses, and the respective light receiving sides are arranged on the output side of the light receiving optical fiber. An element is arranged, the light that has propagated in the light-projecting optical fiber is divided into a plurality of light beams, and these light beams are guided to the movable scale side by the movable-side light angle conversion lens, and the respective light beams are fixed. 2. The conversion device according to claim 1, wherein the light is transmitted through each of the scales, and the transmitted light is guided toward the light receiving optical fiber by the plurality of fixed-side light angle conversion lenses, and is received by the light receiving element. Sensor. 3. The movable scale is formed by forming a large number of concave and convex portions in a longitudinal direction of one surface of the movable-side optical angle conversion lens to form a large number of movable slits. 3. The displacement sensor according to claim 1, wherein a number of uneven portions are formed in a longitudinal direction of one surface of the angle conversion lens to form a number of fixed slits. 4. The moving scale is formed with a number of uneven portions in a longitudinal direction of one surface of the movable-side optical angle conversion lens,
A light blocking film is formed on one of the concave portion and the convex portion of the concave and convex portion to form a large number of movable slits, and the fixed scale is provided with a large number in a longitudinal direction of one surface of the fixed side light angle conversion lens. 3. The displacement sensor according to claim 1, wherein an uneven portion is formed, and a light blocking film is formed on one of a concave portion and a convex portion of the uneven portion to form a plurality of fixed slits. 5. A sensor body, comprising: a fixed scale in which a number of fixed slits are arranged in parallel at a predetermined pitch; and a movable body which senses a displacement of an object to be detected and moves in accordance with the displacement, The movable body is provided with a moving scale in which a large number of moving slits are arranged in parallel at a predetermined pitch, and a displacement sensor that detects a change in the amount of light transmitted through the movable slit and the fixed slit by movement of the moving scale. A light measuring element configured so that the movable scale and the fixed scale are opposed to each other to form a sensor measuring light scale; a light emitting element is arranged outside the sensor body; Forming a light-emitting side mirror at the end of the optical fiber for use, and forming a light-receiving side mirror at the end of the light-receiving optical fiber for guiding the received light to the light receiving element; Each end of an optical fiber for light and an optical fiber for light reception is inserted, and the light emitting side mirror and the light receiving side mirror are opposed to each other with the sensor length measuring optical scale interposed therebetween. And a displacement sensor. 6. The light-emitting side mirror portion is formed by polishing a terminal portion of the light-emitting optical fiber obliquely with respect to a traveling path of light, and the light-receiving side mirror portion is provided with a light-receiving side. The displacement sensor according to claim 5, wherein the end portion of the optical fiber is polished so as to be inclined in a direction opposite to the direction of the light-emitting side mirror portion. 7. The light emitting optical fiber is held by a light emitting optical fiber holder, the light receiving side optical fiber is held by a light receiving side optical fiber holder, and the light emitting optical fiber holder and the light receiving side light are held. 7. The displacement sensor according to claim 6, wherein an opening is provided in each of the fiber holders and a path of light reflected by the light-emitting side mirror and incident on the light-receiving side mirror is formed. 8. The light-projecting side mirror portion is formed by forming a notch in a terminal portion of the light-projecting optical fiber, and polishing and plating a surface portion of the notch. The displacement sensor according to claim 5, wherein the light-receiving side mirror section is formed by forming a notch in a terminal portion of the light-receiving side optical fiber, and polishing and plating a surface of the notch. . 9. A plurality of said fixed scales, said adjacent fixed scales are arranged with their pitches shifted by a predetermined amount, and said combination of said moving scale and each said fixed scale is provided on said sensor body. The displacement sensor according to claim 5, wherein the respective end portions of the corresponding projecting and receiving optical fibers are inserted.