JPH04372821A - Position detecting apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detection device, and more particularly to a position detection device for optically detecting the rotation speed and rotation angle of a rotating body, as well as the moving speed and amount of movement of a linearly moving object.

0002

2. Description of the Related Art Photo encoders are known as sensors for optically detecting rotation angles and linear displacements. For example, as an incremental method, JP-A-64-
There is a method described in Japanese Patent Publication No. 49914, and a method using an absolute method described in Japanese Utility Model Application Laid-Open No. 64-48618.

First, an example of a linear motion sensor using an absolute type photo encoder will be explained with reference to FIG. 3A is a plan view of the pulse generating section, and FIG. 1B is a side view. In FIG. 5, a binary code is displayed on the code plate 51 by a slit 51A. The width direction of the code plate 51 corresponds to the digits of the code, and the longitudinal direction corresponds to the displacement direction 54 of the detected moving body. A light emitting section 55 made up of light emitting elements s1 to s5 is arranged on one surface of the code plate 51, and a light receiving section 5 made up of light receiving elements r1 to r5 is arranged on the other surface.
6 is placed.

The light emitting section 55 and the light receiving section 56 transmit light emitted from the light emitting elements s1 to s5 to the light receiving element r1, respectively.
They are arranged facing each other so as to be detected at ~r5. Either the sensor head in which the light emitting section 55 and the light receiving section 56 are integrated, or the code plate 51 is attached to a moving object to be detected, and moves in the displacement direction 54 together with the moving object. Depending on the relative position between the code plate 51 and the sensor head, only a specific light receiving element of the light receiving section 56 can detect the light projected from the light emitting section 55. Therefore, the relative position between the sensor head and the code plate 51, that is, the position of the moving object to be detected, can be detected by the combination (code) of the output signals of the light receiving elements r1 to r5.

Next, an example of a linear motion sensor using an incremental type photo encoder will be described with reference to FIG. 4A is a side view of the pulse generator, and FIG. 1B is a plan view. In FIG. 6, slits 51a are provided in the code plate 51 at predetermined intervals along the displacement direction 54 of the detected object. Slit 5 of the code plate 51
Two fixed code plates 52 and 53 are arranged opposite to 1a. These fixed code plates 52 and 53 also include the code plate 5.
Similar to 1, slits are provided in each case. Light emitting elements 6a, 6b and light receiving elements 7a, 7b are provided at positions facing each slit of the fixed code plates 52, 53 with the fixed code plates 52, 53 and the code plate 51 in between.

The code plate 51 moves in the displacement direction 54, and the slit of the fixed code plate 53 and the slit 51 of the code plate 51
When a matches, the light emitted from the light emitting element 6a is transmitted to the light receiving element 7.
a, the slit of the fixed code plate 52 and the code plate 5
When the first slits 51a match, the light emitted from the light emitting element 6b is detected by the light receiving element 7b. The output signals (pulse signals) of the light receiving elements 7a and 7b at this time are counted, and the position of the moving object to be detected is detected based on the result. One of the slits in the fixed code plates 52 and 53 is connected to the slit 5.
The interval between the fixed code plates 52 and 53 is set so that when the code plate 1a matches the slit 51a, the other code plate does not match the slit 51a. In other words, the output signals of the light receiving elements 7a and 7b are set to be out of phase. Therefore, in the incremental method, since the displacement direction of the detected moving body can be determined by comparing the output signals of the light receiving elements 7a and 7b, the count value of the pulse signal can be increased depending on the displacement direction.
or decrease it.

[0007]

SUMMARY OF THE INVENTION The above-mentioned conventional position detection device using a photo encoder has the following problems. That is, the position detection device may be used under extremely harsh environments. For example, when a position detection device is used to detect the position of a rotating body of a car,
It may be exposed to high temperatures due to the effects of engine heat.

By the way, semiconductor elements such as light emitting diodes and phototransistors are often used as the light emitting elements and light receiving elements, but these semiconductor elements have the disadvantage that they do not exhibit sufficient performance at high temperatures. Therefore, there has been a problem in that the usable temperature of a position detection device using these elements is limited to a narrow range depending on the temperature characteristics of the elements.

In particular, absolute type photosensors require the same number of light-emitting elements and light-receiving elements as the number of digits of the code, so there is a high probability that detection failures will occur due to abnormalities in the elements.

[0010]In addition, since the incremental type photosensor detects the absolute position based on the count value of the pulse signal, the moving object that always passes through the reference position for counting,
For example, it is unsuitable for application to anything other than a rotating body that rotates continuously in one direction or a reciprocating body that has a constant stroke length.

On the other hand, absolute type photosensors are convenient for detecting absolute positions, but require a large number of light emitting elements and light receiving elements.
There were problems with securing storage space and cost.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a position detection device that can easily detect the absolute position of a moving object used in a harsh environment.

[0013]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a first plate in which a long hole whose width changes in the direction of movement of a detected object, and a first plate with a predetermined interval. a second plate that is overlapped with the first plate and has a slit orthogonal to the elongated hole; a first optical fiber cable that guides light from the light emitting means to an optical path that passes through the elongated hole and the slit; a second optical fiber cable that guides the light that has passed through the elongated hole and the slit to a light receiving means; and a calculation means that determines the positional relationship between the first plate and the second plate based on the detection level of light by the light receiving means. It is characterized by the following features.

[0014] The present invention also provides a first plate in which a long hole whose width changes in the direction of movement of the object to be detected is formed, the first plate being overlapped with the first plate with a predetermined interval, and the long hole a second plate in which a slit orthogonal to the second plate is formed; a light reflecting means provided behind the first plate to reflect light in the incident direction; an optical fiber cable that guides light from the light emitting means to a light path reaching the light emitting means and guides the light reflected by the light reflecting means to the light receiving means, and the detection level of the light reflected by the light reflecting means detected by the light receiving means The second feature is that the apparatus includes a calculation means for determining the positional relationship between the first plate and the second plate. Furthermore, the present invention has a third feature in that, among the second features, the elongated hole itself is constituted by a light reflecting means.

[0015]

[Operation] In the present invention having the above characteristics, the degree of overlap between the slit and the elongated hole or the slit and the light reflecting means changes depending on the relative positions of the first plate and the second plate, and as a result, the slit and the elongated hole are The light reception level changes when the light passing through or the light passing through the slit and reflected by the light reflecting means is detected by the light receiving means.

Therefore, the positional relationship between the first plate and the second plate can be detected based on the level of the received light level. The position of the detected object can be detected by fixing one of the first plate and the second plate to a moving detected object and fixing the other plate at a predetermined position.

[0017] Furthermore, since the light emitting element and the light receiving element can be provided at a position away from the object to be detected via the optical fiber cable, the characteristics of the light emitting element and the light receiving element are not affected by the environment at the installation position of the object to be detected. .

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings. FIG. 1 is a front sectional view of a detection device showing a first embodiment of the present invention, and FIG. 3 is a sectional view taken along line AA in FIG.

In FIGS. 1 and 3, a displacement slit plate, ie, a pendulum 5, is swingably supported by the casing 1 by a shaft 4. As shown in FIGS. The pendulum 5 is provided with a long hole, that is, a displacement-side detection slit 5a and a displacement-side reference slit 5b, the width of which changes in the direction of its swing. The displacement-side reference slit 5b is provided approximately in the middle of the pendulum 5 in the swinging direction, as shown by the chain line when the pendulum 5 swings rightward in the figure. On the other hand, a fixed slit plate 17 is arranged adjacent to the pendulum 5 and fixed to the casing 1. The fixed slit plate 17 has a fixed side detection slit 17.
a and a fixed-side reference slit 17b, the fixed-side detection slit 17a corresponds to the displacement-side detection slit 5a, and the fixed-side reference slit 17b is positioned so as to correspond to the displacement-side reference slit 5b. There is.

Optical fiber cables 8a and 8b whose tips protrude inside the casing 1 are fixed to the mutually opposing wall surfaces of the casing 1. The axes of the optical fiber cables 8a and 8b coincide with each other, and the slit 5a and the slit 17a are positioned on the axis between the optical fiber cables 8a and 8b.

Furthermore, filters 18 and 19 are arranged corresponding to each slit 17a and 17b of the fixed slit plate 17. The filter characteristics of the filters 18 and 19 are adjusted so that the wavelength bands of light transmitted through the filters are shifted from each other.

Furthermore, the fixed slit plate 17 and the pendulum 5
, and half mirrors (semi-plated silver surfaces) 11 and 12 and reflective mirrors 13 and 24 are arranged with a filter 18 in between. The half mirrors 11 and 12 are placed on the optical axis connecting the optical fiber cables 8a and 8b at an angle of 45 degrees with respect to this optical axis.
It is placed at an angle. And the reflection mirror 24
, 13 are arranged parallel to the reflective surfaces of the half mirrors 11 and 12, respectively, and on a line connecting the fixed side reference slit 17b and the displacement side reference slit 5b. The filters 18 and 19 and the half mirror 11
, 12 and reflecting mirrors 13, 24 are fixed to the inner wall of the casing 1 by fixing means (not shown).

The other end surfaces of the optical fiber cables 8a, 8b are fixed to a wall surface 9 of an electronic control device which is a control section of the detection device. A sensor box 10 is attached to the inner surface of the electronic control device, and a light emitting element 6 and light receiving elements 7a and 7b are attached to this sensor box 10. The light emitting element 6 is arranged so that the light generated therein is incident on the optical fiber cable 8a.

On the optical axis of the light that has passed through the optical fiber cable 8b, there are a half mirror 22 and a reflecting mirror 23, which are arranged at an angle of 45° with respect to the optical axis. The light receiving element 7a detects the light reflected by the half mirror 22, and the light receiving element 7b detects the light transmitted through the half mirror 22 and reflected by the reflecting mirror 23.

A filter 20 is arranged in front of the light receiving element 7a, and a filter 21 is arranged in front of the light receiving element 7b. These filters 20, 21 are light receiving elements 7a,
The filter 7b limits the wavelength of light incident on the filter 7b, and the transmission wavelength band of the filter 20 is set to be almost the same as that of the filter 18, and that of the filter 21 is set to be almost the same as that of the filter 19. Therefore, the light that exits the light emitting element 6, passes through the slits 17a and 5a, and returns, passes through the filter 18 on the way, and therefore passes through the filter 20, which has the same transmission wavelength band as this filter 18. The light is received by the light receiving element 7a. On the other hand, the slits 17b, 5
Since the light that has passed through b and returned has passed through filter 19, it passes through filter 21 having the same transmission wavelength band as filter 19 and is received by light receiving element 7b.

Note that the fixed slit plate 17 and the pendulum 5
, and the arrangement order of the filters 18 and 19 is not limited to that shown in FIG. You can. Alternatively, the light after passing through the filters 18 and 19 may pass through each slit. In short, the slit 17 is placed on one of the optical axes divided into two directions by the half mirror 12.
a, 5a and the filter 18 are positioned, and the slits 17b, 5b and the filter 19 are positioned on the other optical axis.

With this configuration, the light emitted from the light emitting element 6 passes through the optical fiber cable 8a and is irradiated onto the half mirror 12. A part of this light passes through the half mirror 12, and the rest is reflected and direction-changed by the half mirror 12 and directed toward the reflecting surface of the reflecting mirror 13.

The light transmitted through the half mirror 12 passes through the displacement side detection slit 5a of the pendulum 5 and the fixed slit plate 17.
The light passes through the fixed side detection slit 17a and the filter 18, and further passes through the half mirror 11 to reach the optical fiber cable 8b.

When the pendulum 5 swings, the position of the displacement detection slit 5a corresponding to the fixed detection slit 17a changes, and the overlapping length of these slits 17a and 5a also changes. As a result, the illuminance of the light incident on the optical fiber cable 8b changes.

That is, when the pendulum 5 swings in the direction of the arrow 25, the overlapping length of the slits 17a and 5a becomes shorter and the illuminance of the light incident on the optical fiber cable 8b decreases, and when the pendulum 5 swings in the opposite direction, is the slit 17a
The overlapping length of the optical fiber cable 8b and the optical fiber cable 5a increases, and the illuminance of the light incident on the optical fiber cable 8b increases.

On the other hand, the light that exits the optical fiber cable 8a, is reflected by the half mirror 12, and is directed toward the reflecting mirror 13, is again changed in direction by the reflecting mirror 13 to the original traveling direction. Then, when the pendulum 5 swings and the displacement side reference slit 5b and the fixed side reference slit 17b match, the slit 5b, the slit 17b, and the filter 1
Pass 9. Then, it is further reflected and direction-changed by the reflective surfaces of the reflective mirror 24 and the half mirror 11, and reaches the optical fiber cable 8b.

[0032] The position detection device configured as described above has the following features:
It can be used as an acceleration sensor for objects. In this case, when acceleration occurs in the object to which the acceleration sensor is attached, the pendulum 5 swings. When the illuminance of the light incident on the optical fiber cable 8b changes with this swing as described above, the illuminance of the light detected by the light receiving element 7a also changes, and the output of the light receiving element 7a changes. For example, if the light receiving element is a photodiode, a change in illuminance can be extracted as a change in current.

Therefore, if the relationship between the magnitude of acceleration and the output current of the light receiving element 7a is investigated in advance, the acceleration can be determined from the output current of the light receiving element 7a based on this relationship. The acceleration can be calculated from the output current of the light receiving element 7a by using a microcomputer according to a predetermined calculation formula, or by preparing a ROM table in which the relationship between acceleration and the output current of the light receiving element is stored and calculating the output signal. A method can be used that outputs the acceleration corresponding to .

The output signal of the light-receiving element 7b, that is, the signal indicating that the displacement-side reference slit 5b and the fixed-side reference slit 17b match, can be used to correct variations in sensor components and circuits, and changes over time. .

That is, in response to the output signal of the light-receiving element 7b, it is determined whether the output current of the light-receiving element 7a matches the initial setting, and if it deviates, the light reception is adjusted based on the amount of deviation. The output current of element 7a can be corrected. From this point of view, the drilling position of the displacement side reference slit 5b is determined based on the possibility that the displacement side reference slit 5b and the fixed side reference slit 17b will coincide when the expected acceleration occurs and the pendulum 5 swings. It is desirable to set it in a high position.

Next, a second embodiment of the present invention will be described with reference to FIG. This second embodiment is an example in which a control device provided with a light receiving section and a light emitting section and the casing 1 are connected by one optical fiber cable. In FIG. 2 and the following description, the same reference numerals as in FIGS. 1 and 3 indicate the same or equivalent parts.

In FIG. 2, the pendulum 5 and fixed slit plate 17 are provided with slits similar to those in the first embodiment. An optical fiber cable 8 whose tip protrudes into the inside of the casing 1 is fixed to one wall surface of the casing 1 . The installation position of this optical fiber cable 8 is
A slit 1 whose end face is provided in a fixed slit plate 17
It is set to correspond to either one of 7a and 17b. Here, it is positioned corresponding to the slit 17a.

A mirror 12a is attached to the wall surface of the casing 1 behind the fixed slit plate 17, that is, on the opposite side from the optical fiber cable 8. In addition, filters 18 and 19 are arranged on the front side of the pendulum 5, that is, on the optical fiber cable 8 side, facing the slits 17a and 17b of the fixed slit plate 17, respectively. The filter characteristics of the filters 18 and 19 are adjusted so that the wavelength bands of light transmitted through the filters are shifted from each other.

Further, a half mirror 11 is arranged in front of the filter 18, and a reflecting mirror 24 is arranged in front of the filter 19. The half mirror 11 and the reflecting mirror 24 are arranged so that their surfaces are parallel to each other, and are arranged at an angle of 45 degrees with respect to the optical axis of the light emitted from the optical fiber cable 8.

The other end face of the optical fiber cable 8 is
It is fixed to the wall surface 9 of the electronic control device. A light emitting element 6 and a light receiving element 7 are installed in the sensor box 10 on the inner surface of the electronic control unit.
a and 7b are attached. The light emitting element 6 is arranged so that the light generated therein passes through the half mirrors 22 and 23a and enters the optical fiber cable 8. On the optical axis connecting the light emitting element 6 and the optical fiber cable 8, between the light emitting element 6 and the optical fiber cable 8, there are half mirrors 22, 23 inclined at 45 degrees with respect to the optical axis.
a is placed.

Further, the light receiving elements 7a and 7b are arranged on the reflective surface side of the half mirrors 22 and 23a, and the light passing through the optical fiber cable 8 is directed to the half mirror 22.
, 23a, the direction of the light is changed, and then the light is incident.

Filters 20 and 21 are provided in front of the light receiving elements 7a and 7b. This filter 20,
21 limits the wavelength of light incident on the light receiving elements 7a and 7b, and its transmission wavelength band is determined by the filter 2.
0 is the filter 18, and filter 21 is the filter 19.
are set to be almost the same. therefore,
The light that exits the light emitting element 6, passes through the slits 17a and 5a, is reflected by the mirror 12a, and returns, passing through the filter 18 on the way, so the filter 20 has the same transmission wavelength band as this filter 18. is transmitted through the light receiving element 7
The light is received at a. On the other hand, the light that passes through the slits 17b and 5b and returns passes through the filter 21 and is received by the light receiving element 7b.

With this configuration, when the light emitted from the optical fiber cable 8 is irradiated onto the half mirror 11,
A part of it passes through the half mirror 11, the rest is reflected and direction-changed by the half mirror 11, and then the reflection mirror 24
It is reflected and redirected by

The light transmitted through the half mirror 11 passes through the filter 18, the slit 17a, and the slit 5a, and reaches the mirror 12a. Then, it is reflected there and enters the optical fiber cable 8 via the original path. On the contrary,
When the slits 5b and 17b match, the light reflected by the half mirror 11 and the reflection mirror 24 and whose direction is changed passes through the filter 19, the slit 17b, and the slit 5b, and reaches the mirror 12a. Then, it is reflected there and enters the optical fiber cable 8 via the original path.

The amount of swing of the pendulum 5 is detected based on the magnitude of the output current detected by the light receiving element 7a according to the position where the slits 5a and 17a overlap when the pendulum 5 swings. , is similar to the first embodiment.

Note that instead of providing the slits 5a and 5b in the pendulum 5, the pendulum 5 may be formed so that the light reflectance is different between the portions corresponding to these slits and the remaining portions. good. For example, the part corresponding to the slit is painted with a silver or white color that has high light reflectance.
The slit can be substituted by painting the remaining part black. By doing this, the mirror 12a
can be omitted.

Next, a third embodiment of the present invention will be described with reference to FIG. In the first and second embodiments described above, the detected moving body was a swinging pendulum, but in this third embodiment, an example in which the detected moving body reciprocated in a straight line is shown. Note that here, the light emitting section and the light receiving section that supply light and receive the light, and the optical fiber cable that connects the two may have the same configuration as in the above embodiment, so illustration thereof is omitted.

In FIG. 4, a block 50 is fitted into the casing 1 so as to be able to reciprocate in the direction of an arrow 26. As shown in FIG. This block 50 is pressed from left and right by compression springs 60 and 70, and is adjusted to be balanced approximately at the center of the casing 1. Like the pendulum 5, the block 50 includes a displacement side detection slit 50a and a displacement side reference slit (not shown). Further, the fixed slit plate 80 is provided with a fixed side reference slit 80a and a fixed side reference slit 80b. This fixed slit plate 8
0 is fixed to the lid of the casing 1 or the like.

When the block 50 is displaced in the direction of the arrow 26 due to acceleration, for example, the amount of overlap between the displacement side detection slit 50a and the fixed side displacement slit 80a changes, so the output of the light receiving element corresponding to this change causes the first Similarly to the second embodiment, the magnitude of the acceleration applied to the block 50 can be detected.

Note that the half mirror 1 shown in FIGS. 1 and 2
Filters 18 and 19 can be omitted by changing 1 or 12 to a dichroic mirror such as a cold mirror or a hot mirror. That is, the dichroic mirror can transmit light of a specific wavelength and reflect other light, so it can function as both the half mirror 11 and the filters 18 and 19. Similarly, a prism may be used instead of the half mirror 11 or 12 to divide light entering from a common optical path into multiple optical paths with different wavelength bands, and guide the light to a predetermined slit using an optical means such as a reflecting mirror. You can also do this. Also, by adjusting the band sensitivity of the light receiving elements 7a and 7b,
It is possible to limit the band of light incident on the light receiving elements 7a, 7b.

Furthermore, in this embodiment, the wavelength bands of filters 18 and 20 and the wavelength bands of filters 19 and 21 are made to match, respectively.
8 and 19 as polarizing filters, and filters 20 and 19 as polarizing filters.
21 is an analysis filter, and the light polarized by the polarization filter 18 is detected by the light receiving element 7a via the analysis filter 20.
The light polarized by the polarizing filter 19 may be configured to be detected by the light receiving element 7b via the analysis filter 21.

[0052]Although this embodiment shows the case where the detected amount is acceleration, the present invention can also detect the position of a rotating body, the position of a moving body moving in a straight line, etc. Of course, it can also be applied to detecting the amount of movement.

In addition, in this embodiment, reference slits on the displacement side and on the fixed side were provided as correction slits to correct the output of the light receiving element, but depending on the object for which the detection device is used, it may be possible to use it without correction. In this case, the correction slit and the optical means for guiding light to this slit can also be omitted.

[0054]

As is clear from the above description, according to the present invention, the following effects can be obtained. (1) The absolute position of the object to be detected can be detected with a small number of parts depending on the detection level of the light receiving element. (2) The object to be detected and the semiconductor elements such as the light emitting element and the light receiving element, which are the constituent elements of the detection sensor, can be installed at separate locations. Therefore, even if the object to be detected is a rotating body near the engine of an automobile, where the temperature tends to be high, the semiconductor element is not affected by the temperature. (3) Since there is no need to provide a semiconductor element or a circuit board for attaching these near the detected object, the position of the detected object can be detected even when there is little space around the detected object. can. (4) Since the detection result of the position of the detected object can be guided to the electronic control device without going through the electric signal line, it is less susceptible to noise. (5) Since a plurality of position detection signals can be transmitted to a plurality of light receiving elements using one optical fiber cable, it is economical and space can be used effectively.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a position detection device showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a position detection device showing a second embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA in FIG. 1.

FIG. 4 is a sectional view of a main part of a position detection device showing a third embodiment of the present invention.

FIG. 5 is a diagram showing a conventional absolute encoder.

FIG. 6 is a diagram showing a conventional encoder using an incremental method.

[Explanation of symbols]

4... Axis, 5... Pendulum, 5a, 17a, 17b...
slit, 6... light emitting element, 7a, 7b... light receiving element,
8, 8a, 8b...optical fiber cable, 11
, 12, 22, 23... Half mirror, 17... Fixed slit plate, 18, 19, 20, 21... Filter,
23, 24...Reflection mirror

Claims (10)

[Claims] 1. A device comprising a light emitting means and a light receiving means, wherein the light emitted from the light emitting means is transmitted through a predetermined slit, and the light receiving means is arranged to receive the transmitted light. In a position detection device for detecting the position of a body, a first plate in which a long hole whose width changes in the direction of movement of the detected object is formed, and a first plate having a predetermined interval therebetween;
a second plate overlapped with the plate and having a slit orthogonal to the elongated hole; a first optical fiber cable that guides light from the light emitting means to an optical path passing through the elongated hole and the slit; It is characterized by comprising a second optical fiber cable that guides the passed light to a light receiving means, and a calculating means that determines the positional relationship between the first plate and the second plate based on the detection level of light by the light receiving means. position detection device. 2. A detection target having a light emitting means and a light receiving means, the light emitted from the light emitting means being transmitted through a predetermined slit, and based on the detection signal of the light receiving means arranged to receive the transmitted light. In a position detection device for detecting the position of a body, a first plate in which a long hole whose width changes in the direction of movement of the detected object is formed, and a first plate having a predetermined interval therebetween;
a second plate that is overlapped with the plate and has a slit orthogonal to the elongated hole; a light reflecting means that is provided behind the first plate and reflects light in the incident direction; an optical fiber cable that guides light from the light emitting means to an optical path through which the light is transmitted in order and reaches the light reflecting means, and also guides the light reflected by the light reflecting means to the light receiving means; and the light reflecting means detected by the light receiving means. A position detection device characterized by comprising: calculation means for determining the positional relationship between the first plate and the second plate based on the detection level of reflected light. 3. A detection target having a light emitting means and a light receiving means, the light emitted from the light emitting means being transmitted through a predetermined slit, and the light receiving means arranged to receive the transmitted light based on a detection signal. In a position detection device for detecting the position of a body, a first plate on which a light reflecting surface whose width changes in the direction of movement of a detected object is formed, the first plate being overlapped with the first plate at a predetermined interval, a second plate in which a slit orthogonal to the light reflecting surface is formed; a second plate that guides light from a light emitting means to an optical path that passes through the slit and reaches the light reflecting surface; an optical fiber cable leading to a light receiving means; and a calculation means for determining a positional relationship between the first plate and the second plate based on a detection level of light reflected by the light reflecting surface detected by the light receiving means. Characteristic position detection device. 4. A first plate formed on the first plate so as to coincide with each other at a predetermined position as the detected object moves.
A correction slit and a second correction slit formed in the second plate branch the light guided by the first optical fiber cable into two optical paths, and the light that has traveled through these two optical paths is divided into the second correction slit and the second correction slit formed in the second plate. and a filter means disposed in the two branched optical paths to transmit light according to mutually different selection criteria. The elongated hole of the first plate and the slit of the second plate are located on one side of the optical path, and one of the first and second correction slits is located on the other side, and the other slit when coincident with the one slit is located on the other side. 2. The position detection device according to claim 1, wherein the light receiving means is configured to selectively receive the light transmitted through the filter means. 5. A first plate formed on the first plate so as to coincide with each other at a predetermined position as the detected object moves.
a correction slit and a second correction slit formed in the second plate; an optical means for branching the light guided by the optical fiber cable into two optical paths; and filter means for transmitting light according to selection criteria, and the optical means includes a long hole of the first plate and a slit of the second plate located in one of the two branched optical paths, and One of the first and second correction slits and the other slit are set to be positioned when the first and second correction slits coincide with each other, and the light receiving means selectively receives the light transmitted through the filter means. 3. The position detecting device according to claim 2, wherein the position detecting device is configured to receive light. 6. A correction slit provided on the first plate and a correction light reflecting surface formed on the second plate so as to coincide with each other at a predetermined position as the detected object moves, and the optical fiber cable. an optical means for branching the light guided by the light into two optical paths;
filter means arranged in two optical paths and transmitting light according to mutually different selection criteria;
The light-reflecting surface of the plate and the slit of the second plate are located on the other side, and the correction slit and the correction light-reflecting surface when coincident with the correction slit are located on the other side, and the light receiving means is 4. The position detection device according to claim 3, wherein the device is configured to selectively receive the light that has passed through the filter means. 7. The position detection device according to claim 4, wherein the filter means is a filter having transmission wavelength bands different from each other. 8. The position detection device according to claim 4, wherein the filter means is a polarizing filter having mutually different polarization angles. 9. The light receiving means includes a plurality of light receiving elements;
Claims 4 to 4, characterized in that the filter is disposed in front of each light receiving element and is comprised of filters each having a different transmission wavelength band.
8. The position detection device according to 8. 10. The light-receiving means comprises a plurality of light-receiving elements and analysis filters arranged in front of each light-receiving element and each having a different polarization angle.
9. The position detection device according to 9.