JPH0618285A - Detecting apparatus for rotating angle - Google Patents

Abstract

PURPOSE:To detect the rotating angle theta of a rotary plate even in a discontinu ous area of a detecting transmitting part in a simple and inexpensive constitu tion. CONSTITUTION:A spiral light transmitting part 25 for detection purpose and an annular reference light transmitting part 26 of a predetermined radius are formed in a rotary plate 23. A light transmitting part 26a for distinction purpose with a large width is formed in the reference light transmitting part 26 corresponding to a discontinuous area at each end part of the light transmitting part 25. LEDs 27, 28, and a detecting PSD 29 and a reference PSD 30 are respectively provided to confront each other and to hold the detecting light transmitting part 25 and reference light transmitting part 26 in-between. Since the light enters the reference PSD 30 through the light transmitting part 26a in the discontinuous area of the light transmitting part 25, the total detecting amount of light is increased. Therefore, the rotating area of the rotary plate 23 can be identified, and the rotating angle theta of the rotary plate 23 can be detected in the whole periphery of the plate 23 from detecting signals of the PSD 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a light projecting element and a semiconductor position detecting element that face each other with a rotary plate attached to a rotary shaft interposed therebetween, and the rotary plate is based on a light receiving signal from the semiconductor position detecting element. The present invention relates to a rotation angle detection device that detects the rotation angle of a.

[0002]

2. Description of the Related Art An example of a rotation angle detecting device of this type is shown in FIG.
It will be described with reference to FIGS. This is configured such that the rotation angle of the rotary plate can be detected with high accuracy even when "rattle" is generated between the rotary shaft and the rotary plate.

That is, in FIG. 12, a rotary plate 2 is attached to a rotary shaft 1 so as to rotate integrally with the rotary shaft 1, and the rotary plate 2 has a spiral shape with respect to a rotation center O for detection. The light-transmitting portion 3 is formed, and a reference light-transmitting portion 4 is formed near the outer periphery of the light-transmitting portion 3 and has an annular shape with a predetermined radius.

Further, a light emitting diode (hereinafter referred to as LED) 5 and a semiconductor position detecting element for detection (Position) sandwiching a light transmitting portion 3 for detection of a rotary plate 2 in a fixed portion (not shown).
Sensitive Detector (hereinafter abbreviated as PSD) 6 is arranged so as to face each other, and LED 7 and reference PSD 8 are arranged so as to face each other with reference light transmitting portion 4 interposed therebetween. The detection PSD 6 and the reference PSD 8
Are arranged to detect the position of incident light that changes in the radial direction of the rotary plate 2.

In FIG. 13 showing the outline of the electrical configuration,
The outputs of the detection PSD 6 and the reference PSD 8 are given to a subtractor 11 via amplifiers 9 and 10, respectively. Amplifier 9,
10 is the current signals S1 and S provided from the PSDs 6 and 8
2 is amplified and converted into voltage signals V1 and V2 for output, and the subtractor 11 uses the difference V between the voltage signals V1 and V2.
12 (= V1-V2) is calculated and output.

According to the above construction, when the rotary plate 2 rotates, the detection light transmitting portion 3 and the reference light transmitting portion 4 are correspondingly rotated.
Moves in rotation. In this case, the reference light transmitting portion 4 is the rotating plate 2
Since it is formed in an annular shape with the center of rotation O as the center, the position of the light incident on the reference PSD 8 from the LED 7 through the reference light-transmitting portion 4 is theoretically maintained even in the state of rotational movement. It does not change.

On the other hand, since the light-transmitting portion for detection 3 which is rotationally moved with the rotation of the rotary plate 2 is formed in a spiral shape, its radial distance r changes linearly with respect to the rotation angle θ. . That is, the position of the light that enters the detection PSD 6 from the LED 5 through the detection light transmitting portion 3 is determined by the rotation angle θ of the rotating plate 2.
It will change continuously according to. At this time, the light reception signal S1 of the detection PSD 6 is obtained as S1 = A × θ + B (1) (where A and B in the equation (1) are constants), and the light reception signal of the reference PSD 8 is obtained. S2 is obtained as S2 = C (constant) (2).

In the amplifiers 9 and 10, the received light receiving signals S1 and S2 are amplified and converted into voltage signals V1 and V2, which are applied to the subtractor 11. Subtractor 1
1 calculates the difference V1-V2 between the applied voltage signals V1 and V2 and outputs it as an output signal V12. Therefore, the subtractor 11 outputs the output signal V12 as a value corresponding to the value S12 (= S1−S2) obtained by subtracting S2 from the light receiving signal S1.
Will be output from. That is, equations (1) and (2)
From S12, S12 = S1-S2 = A * [theta] + (BC) = A * [theta] + D (3), so S12, that is, the output V12 of the subtractor 11 is a value proportional to the rotation angle [theta]. Can be obtained (however D
(= B-C) is a constant). Therefore, as described above, the rotary plate 2 is based on the value of the output voltage V12 of the subtractor 11.
Since the rotation angle θ of the rotary plate 2 can be associated with each other as shown in FIG. 14, the rotation angle θ of the rotary plate 2 can be detected in a wide range from the reference position (0 °) to nearly 360 °.

The rotary plate 2 is attached at a position eccentric to the rotary shaft 1, or "rattle" is generated between the rotary shaft 1 and the bearing portion, so that the rotary position of the rotary plate 1 is changed. When it is unstable, the received light signals S1 and S2 from the PSDs 6 and 8 both fluctuate unstablely,
The relationships of equations (1) and (2) are no longer satisfied.

However, even in the case as described above, the relative positions of the light-transmitting portion for detection 3 and the light-transmitting portion for reference 4 formed on the rotary plate 2 do not change, so the PSD 6,
The values of the received light signals S1 and S2 of 8 are output as signals obtained by adding or subtracting equally to the extent that the rotating plate 2 is eccentric.

Therefore, if the deviation component of the received light signal due to the eccentricity of the rotary plate 2 at the rotation angle θ is ΔS, then PSD
From equations (1) and (2), the received light signals S1 and S2 of 6 and 8 can be expressed as S1 = A × θ + B + ΔS (4) S2 = C + ΔS (5), from which the subtractor 11 Output V1
When the signal S12 corresponding to 2 is obtained according to the equation (3),
Since the deviation component ΔS due to the eccentricity of the rotary plate 2 cancels out, the result is the same as the result of the equation (3).

That is, even if there is a deviation component ΔS of the received light signal caused by the eccentricity of the rotary plate 2, the relative positional relationship between the light transmitting portion 3 for detection and the light transmitting portion 4 for reference is unchanged. The deviation component ΔS is canceled by the subtraction in the subtractor 11, and the same detection result as in the normal case where no eccentricity occurs can be obtained. As a result,
Even when the position of the light transmitted through the light-transmitting portion for detection 3 becomes unstable, such as when the rotating plate 2 is eccentric or "rotation" occurs on the rotating shaft 1, the rotation angle θ of the rotating plate 2 Can be accurately detected over a wide range.

[0013]

However, the conventional structure as described above has the following problems.
That is, as shown in FIG. 14, in the region (a) near the rotation angle 0 ° where both ends 3a and 3b of the translucent part 3 for detection are located, the value of the output V12 changes rapidly, Since the range of the changing level is the same as the range of the changing level of the other region (a), the rotation angle θ of the rotary plate 2 cannot be reliably detected only by the level value of the output V12. .

In order to solve such a problem, for example, it is conceivable to provide another detecting element at that position for identification, but this makes the configuration as a whole complicated and the cost thereof high. There is a problem that causes

The present invention has been made in view of the above circumstances, and an object thereof is rotation capable of accurately detecting the rotation angle θ of the rotating shaft over the entire region of 360 ° with a simple and inexpensive structure. An object is to provide a corner detecting device.

[0016]

A rotation angle detecting device of the present invention includes a rotating plate attached to a rotating shaft, and a reference light transmitting portion of a constant width formed in an annular shape on the rotating plate with a predetermined radius. A detection translucent part having a constant width formed in a shape along the circumferential direction of the rotary plate and in which the distance from the rotation center of the rotary plate continuously changes; and the reference translucent part and the detection transmissive part. A light projecting element that projects light toward a light section, and a light transmitting element that is disposed so as to face the light projecting element with the rotating plate interposed therebetween, receives light that has passed through the reference light transmitting section, and is arranged in a radial direction of the rotating plate. A reference semiconductor position detecting element for detecting a light receiving position and a light transmitting through the detecting translucent portion, which is arranged so as to face the light projecting element with the rotating plate interposed therebetween, and receives light in the radial direction of the rotating plate. A semiconductor position detection element for detection that detects the light receiving position and these reference semiconductor positions. And a calculating means for calculating the rotation angle of the rotating plate based on the light receiving signals from the detecting element and the detecting semiconductor position detecting element, and the rotating plate is discontinuous at both ends of the detecting transparent portion. It is characterized in that either one of the detection light-transmitting portion or the reference light-transmitting portion is provided with an identification light-transmitting portion having a width dimension different from that of the other portion in correspondence with the angular position.

[0017]

According to the rotation angle detecting device of the present invention, the rotation angle of the rotary plate can be detected accurately over the entire circumference thereof as follows. That is, since the reference light-transmitting portion of the rotating plate is formed in a ring shape with a predetermined radius, the light receiving position of the light incident from the light projecting element to the reference semiconductor position detecting element is the same regardless of the rotation of the rotating plate. The position in the direction is a fixed position. On the other hand, since the detection light transmitting portion of the rotating plate has a shape in which the distance from the rotation center thereof continuously changes, the discontinuity points (for example, near 0 °) at both ends of the detection light transmitting portion are excluded. In the portion, the light receiving position of the light incident on the detection position detecting element from the light projecting element continuously changes according to the rotation angle as the rotating plate rotates.

Therefore, when the calculating means calculates the difference between the position detected by the light receiving signal from the reference semiconductor position detecting element and the position detected by the light receiving signal from the detecting semiconductor position detecting element, the rotation of the rotary plate The value corresponding to the angle can be obtained. In this case, even if there is "rattle" between the rotary shaft and the bearing, or the mounting state between the rotary plate and the rotary shaft is eccentric, the reference transparency corresponding to the rotation angle of the rotary plate is generated. Since there is no error in the relative distance between the light section and the light transmitting section for detection, the rotation angle of the rotary plate can be detected with high accuracy.

Then, at the discontinuous point portion where both ends of the detecting light projecting portion are located, the light receiving position of the light from the light projecting element incident on the detecting semiconductor position detecting element changes abruptly. At this time, since the light from the light projecting element incident on the semiconductor position detecting element generally has a slight spread, the level of the detected signal is at the end of the discontinuous point (for example, when the rotation angle θ is 360 ° or more). Change to a level at which the discontinuity begins (position where the rotation angle θ is 0 °).

However, at this discontinuous point portion,
Since the identification light projecting portion having a width dimension different from that of the other portion is formed on either the reference light transmitting portion or the detection light transmitting portion, the level of all incident light at that time changes. . Therefore, it is possible to identify that the rotation position of the rotating plate is at the discontinuous point portion (rotation angle is near 0 °) by detecting the amount of light incident through the light transmitting portion for identification. ,
Even if the signal output from the computing means has the same level as in the case described above, this can be distinguished, and therefore, the rotation angle can be accurately detected over the entire circumference of the rotary plate.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

That is, in FIG. 2 showing the longitudinal side surface, the rotary shaft 21 is pivotally supported by the case 22, which rotates in accordance with the rotation of the detection target (not shown). A disc-shaped rotary plate 23 is fixed to the rotary shaft 21. The rotary plate 23 is mainly composed of a transparent member such as glass or plastic, and a metal film such as chromium is deposited on the surface thereof to form an opaque layer 24.

The opaque layer 24 is partially removed by etching, and as shown in FIG. 1, a light transmitting portion 25 for detection and a light transmitting portion 26 for reference are formed.
The reference light transmitting portion 26 is formed in an annular shape at a position with a predetermined radius from the rotation center O of the rotating plate 23. Further, the light-transmitting portion 25 for detection is located inside the light-transmitting portion 26 for reference, and the distance r with respect to the rotation center of the rotating plate 23 is the reference position (θ = 0 °).
It is formed so as to continuously change in proportion to the rotation angle θ from. When this relationship is expressed by an equation, r = a × θ + b (6), where a and b are constants determined by the shape of the light-transmitting portion 25 for detection.

At the portion corresponding to the reference position (θ = 0 °), the detection light transmitting portion 25 has the relationship of the above-mentioned equation (6), and therefore, the distance between the both ends 25a and 25b thereof. In other words, the rotation angle θ is discontinuous in the portion from near 360 ° to 0 °. The reference light-transmitting portion 26 has an identification light-transmitting portion 16a formed at a position corresponding to the discontinuous portion of the detection light-transmitting portion 25, the width dimension of which is larger than that of the other portions.

A light emitting diode (hereinafter referred to as LE
D) 27 and 28 are provided on the upper surface inside the case 22, and a detection semiconductor position detection element (hereinafter referred to as detection PSD) 29 and a reference semiconductor position detection element (hereinafter referred to as reference PSD). 30 is arranged on the lower surface inside the case 22 so as to detect the light receiving position in the radial direction of the rotary plate 23. Then, the LED 27 and the PSD for detection 29
Are arranged so as to face each other with the detection transparent portion 25 of the rotary plate 23 interposed therebetween, and the LED 28 and the reference PSD 30 are arranged so as to face each other with the reference transparent portion 26 of the rotary plate 23 interposed therebetween. .

Now, FIG. 3 shows an electrical block configuration. In the detection PSD 29, one output terminal thereof is connected to one input terminal of the adder 32 via the current-voltage conversion circuit 31, The other output terminal is connected to the other input terminal of the adder 32 via the current-voltage conversion circuit 33 and is also connected to one input terminal of the subtractor 34. The current-voltage conversion circuits 31 and 33 are respectively
Detection currents I1 and I input from the detection PSD 29
2 is converted into voltage signals V1 and V2 and output, and the adder 32 calculates the sum of these voltage signals V1 and V2 and outputs it as a voltage signal VTa (= V1 + V2).

One input terminal of the feedback circuit 35 is an adder 3
The second input terminal is connected to the output terminal of the reference voltage generating circuit 36, and the other input terminal is connected to the output terminal of the reference voltage generating circuit 36 so that the reference voltage VS is applied. The output terminal of the feedback circuit 35 is grounded via the LED 27 so that the LED 27 is supplied with a conducting current IL1. in this case,
The feedback circuit 35 controls the conduction current IL1 to the LED 27 so that the value of the voltage signal VTa from the adder 32 becomes equal to the reference voltage VS.

Next, in the reference PSD 30, one of its output terminals is connected to the adder 3 via the current-voltage conversion circuit 37.
8 is connected to one input terminal, and the other output terminal is connected to the other input terminal of the adder 38 via the current-voltage conversion circuit 39 and the other input terminal of the subtractor 34. The current-voltage conversion circuits 37 and 39 convert the detection currents I3 and I4 input from the reference PSD 30 into voltage signals V3 and V4, respectively, and output the voltage signals V3 and V4. The adder 38 outputs the voltage signals V3 and V4. The sum is calculated and output as a voltage signal VTb (= V3 + V4).

One input terminal of the feedback circuit 40 is an adder 3
8 is connected to the output terminal, and the other input terminal is connected to the output terminal of the reference voltage generation circuit 36 so that the reference voltage VS is applied. The output terminal of the feedback circuit 40 is grounded via the LED 28 and the current detection resistor 41 so that the LED 28 is supplied with a conduction current IL2. In this case, the feedback circuit 40 uses the adder 38.
The energizing current IL2 to the LED 28 is controlled so that the value of the voltage signal VTb from the LED becomes equal to the reference voltage VS.

The subtractor 34 subtracts the value of the voltage signal V4 output from the current-voltage conversion circuit 39 from the voltage signal V2 output from the current-voltage conversion circuit 33, and the result is detected voltage V.
The data is output as D (= V2-V4).
The common connection point between the LED 28 and the current detection resistor 41 is the rotation area identification terminal P, and the terminal voltage VJ of the current detection resistor 41 is output according to the current IL2 flowing through the LED 28 and the current detection resistor 41. ing.

Next, the operation of this embodiment will be described with reference to FIG. When the rotary shaft 21 and the rotary plate 23 rotate with the rotation of the detection target (not shown), the detection light transmitting portion 25 and the reference light transmitting portion 26 rotate and move accordingly. In this case, since the reference light-transmitting portion 26 is formed in an annular shape centering on the rotation center O of the rotary plate 23, in principle, even when the reference light-transmitting portion 26 rotates, the LED 28 causes the reference light-transmitting portion 2 to rotate.
The position of the light incident on the reference PSD 30 via 6 does not change.

Further, since the light-transmitting portion for detection 25, which rotates with the rotation of the rotary plate 23, is formed in a spiral shape in which the distance in the radial direction changes according to the relationship shown in the equation (6), LE
PSD 29 for detection from D27 through the translucent part 25 for detection
The position of the light incident on is continuously changed except for the region where the rotation angle θ of the rotary plate 23 is near 0 °.

In this case, when the rotation angle θ of the rotary plate 23 is near 0 °, it is a discontinuity point where both ends 25a and 25b of the light transmitting part 25 for detection are located, and therefore the position of the light incident on the PSD 29 for detection is determined. Does not change continuously. Therefore, in this embodiment, the reference light-transmitting portion 26 is provided with the identification light-transmitting portion 26a, and the detection of this portion will be described later. In the following, first, the region except the rotation angle θ of the rotary plate 23 near 0 ° will be described.

Now, according to the rotation angle θ of the rotating plate 23, the position d1 of the light incident from the LED 27 on the light receiving surface of the detecting PSD 29 is obtained from the equation (6) as a value which is displaced in the radial direction, and A, If B is a constant, it can be expressed as d1 = Aθ + B (7).

Further, an LED is provided on the light receiving surface of the reference PSD 30.
Since the position d2 of the light incident from 28 is a constant position regardless of the rotation angle θ of the rotary plate 23 as described above, when C is a constant, it can be expressed as d2 = C (8).

On the other hand, the detection current I1, of the detection PSD 29,
I2 is input to the adder 32 as voltage signals V1 and V2 via the current-voltage conversion circuits 31 and 33, respectively, and is input to the feedback circuit 35 as a voltage signal VTa of the sum thereof. Thus, the feedback circuit 35 energizes the LED 27 so as to reduce the difference voltage when the value of the voltage signal VTa is larger than the reference voltage VS, and increases the difference voltage when the value is smaller. LED27
Energize. As a result, the output current I corresponding to the total amount of light received from the LED 27 that is incident on the detection PSD 29 is obtained.
The value of the sum (I1 + I2) of 1 and I2 is controlled to be always constant.

In the same manner, the reference PSD 30
Detected currents I3 and I4 of the current-voltage conversion circuit 3 respectively.
8 and 40 to adder 38 as voltage signals V3 and V4.
Is input to the feedback circuit 40 as a voltage signal VTb of the sum thereof. As a result, the feedback circuit 40 controls the energizing current to the LED 28 so that the value of the voltage signal VTb becomes substantially constant corresponding to the value of the reference voltage VS. Then, the LED 28 incident on the reference PSD 30
The value of the sum (I3 + I4) of the output currents I3 and I4 corresponding to the total amount of received light from is always controlled to be equal to (I1 + I2) and constant.

As a result, a value corresponding to the detection position d1 is obtained by the signal voltage V2 output from the current-voltage conversion circuit 33, and a value corresponding to the detection position d2 is obtained by the voltage signal V4 output from the current-voltage conversion circuit 39. Is obtained. Therefore, the voltage signal VD (= V2-V4) output from the subtractor 34 that calculates the difference between them is the detection positions d1 to d.
It can be obtained as a value corresponding to the distance obtained by subtracting 2.

As a result, by detecting the voltage signal VD, from the equations (7) and (8), d1-d2 = A × θ + (BC) = A × θ + D (9) Voltage signal VD output from the subtractor 34
Is obtained as a value proportional to the rotation angle θ of the rotary plate 23 (however, in the equation (9), D (= B−C) is a constant).

Therefore, the rotation angle θ of the rotary plate 13 is determined based on the value of the output voltage VD of the subtractor 34 as described above.
Since they can be associated with each other, the rotation angle θ of the rotary plate 13 can be detected in a range other than the reference position where the rotation angle θ is around 0 °.

By the way, the rotary plate 23 is attached at a position eccentric to the rotary shaft 21 or the rotary shaft 2
When the rotational position of the rotary plate 23 becomes unstable due to "rattle" between the bearing No. 1 and the bearing portion of the case 22, the light receiving signals V2 and V4 from the PSDs 29 and 30 are both unstable. As a result, the relationship of equations (7) and (8) cannot be satisfied.

However, even in the above-mentioned case, the relative positions of the light-transmitting portion for detection 25 and the light-transmitting portion for reference 26 formed on the rotary plate 23 do not change, and therefore PS
The values of the received light signals V2 and V4 of D29 and 30 are output as signals obtained by adding or subtracting equally to the extent that the rotating plate 23 is eccentric.

Therefore, the rotary plate 23 at the rotation angle θ now.
Let Δd be the deviation component of the received light signal due to the eccentricity of
The received light signals V2 and V4 of D29 and 30 are expressed by the equations (7),
From (8), it can be expressed as d1 = A × θ + B + Δd (10) d2 = C + Δd (11), from which a voltage signal VD ′ corresponding to the voltage signal VD output from the subtractor 34 can be expressed by the equation (9). )
, The deviation component Δd due to the eccentricity of the rotary plate 23 is canceled, and as a result, the same value as the value shown in the equation (9) is obtained.

That is, even if there is a deviation component Δd of the received light signal caused by the eccentricity of the rotary plate 23, the light transmitting portion 2 for detection is used.
Since the relative positional relationship between 5 and the reference light transmitting portion 26 is unchanged, the deviation component Δd is canceled by the subtraction in the subtractor 34, which is the same as in the normal case where no eccentricity occurs. The detection result can be obtained.

Next, when the rotary plate 23 is near the reference position of the rotation angle θ = 0 °, the rotation angle θ is detected as follows. That is, in this area, the detection PSD 2
The light receiving position of the light from the LED 27 which is incident on 9 is abruptly moved between the both end portions 25a and 25b of the detection light transmitting portion 25.

In this case, since the light of the light emitting diode generally spreads a little, the light of the LED 27 in this region is the same as the light incident on the PSD for detection 29 through the one end 25a of the light transmitting portion for detection 25. The amount of light incident on the detection PSD 29 via the other end 25b gradually changes as the rotary plate 23 rotates. Therefore, the voltage signal VD obtained from the subtractor 34 on the basis of the signal received by the detecting PSD 29 at this time changes linearly as shown in FIG.

Since such a change in the voltage signal VD is the same as the above-described change region except for the rotation angle θ of the rotary plate 23 near 0 °, the rotation angle θ is obtained only from the value of the voltage signal VD.
Cannot be specified. Therefore, based on the terminal voltage VJ given from the rotation area identification terminal P, the rotation plate 23
The rotation area of is identified as follows.

That is, as described above, the detection currents I3 and I4 of the reference PSD 30 are controlled by the feedback circuit 40 so that the value of the sum (I3 + I4) is always constant. On the other hand, when the rotation angle θ of the rotary plate 23 is near 0 °, the identification light-transmitting portion 26a of the reference light-transmitting portion 26 is positioned with respect to the reference PSD 30. Since the width of the light-transmitting portion 26a for identification is wider than the other portions,
The amount of light incident from the LED 28 will be increased.

Then, the value of the sum (I3 + I4) of the detection currents of the reference PSD 30 becomes large, so that the feedback circuit 40
Represents the amount of light incident on the reference PSD 30 by the reference voltage VS.
In order to reduce the current to a value corresponding to, the energizing current IL2 to the LED 28 is controlled to be reduced. Since the terminal voltage of the current detection resistor 41 decreases when the current IL2 supplied to the LED 28 decreases, the terminal voltage VJ appearing at the rotation region identification terminal P has a rotation angle θ of 0 ° as shown in FIG. 4A.
Low level in nearby areas. Therefore, when the level of the terminal voltage VJ appearing at the rotation area identification terminal P is decreasing, it can be identified that the rotation angle θ of the rotary plate 23 is in the vicinity of 0 °, and thus the value of the voltage signal VD is determined. Based on this, the rotation angle θ of the rotary plate 23 can be detected.

As described above, in this embodiment, the reference light-transmitting portion 26 corresponds to the position of the discontinuous point of the light-transmitting portion 25 for detection formed on the rotary plate 23, that is, both ends 25a and 25b.
The light-transmitting portion for identification 26a having a wider width than other portions.
Is provided, and the PSD 28 for reference is changed from the LED 28 in this portion.
The change in the amount of light to the detector is detected by the current detection resistor 41 so that it can be identified. Therefore, the voltage signal V from the subtractor 34 is changed.
Even in a region where the rotation angle θ cannot be detected only by the value of D, it is possible to surely detect with a simple structure without providing another detector or the like.

Further, in this embodiment, the feedback circuit 35
And 40 are provided, and based on the voltage signals VTa and VTb provided through the adders 32 and 38, the LED2
Since the currents of 7 and 28 are controlled so that the amounts of light incident on the detection PSD 29 and the reference PSD 30 are always equal and constant, one voltage of each of the voltages output from the detection PSD 29 and the reference PSD 30 is output. Signal V2
And V4 can be used as they are as a value proportional to the detection position. Therefore, even when there is "rattle" between the rotary shaft 21 and the rotary plate 23, the rotary shaft 2 can be accurately constructed with a structure that does not require a divider that is expensive and requires complicated adjustment.
Since the rotation angle θ of 1 can be detected, it can be manufactured with a simple structure that is inexpensive and does not require adjustment.

FIG. 5 and FIG. 6 show the second embodiment of the present invention, and the portions different from the first embodiment will be described below. That is, in FIG. 5, the current detection resistor 41 and L
The common connection point with the ED 28 is connected to the rotation area identification terminal P via the comparator 42.
The reference voltage VK is applied to the reference input terminal of.

As a result, instead of the terminal voltage of the current detection resistor 41 given to the rotation area identifying terminal P in the first embodiment, a digital signal S1 as shown in FIG. The output from the comparator 42 can be obtained. As a result, the rotation area of the rotary plate 23 can be identified. Therefore, the same effect as that of the first embodiment can be obtained, and the identification can be performed digitally.

FIGS. 7 and 8 show a third embodiment of the present invention, and the portions different from the first embodiment will be described below. That is, FIG. 7 shows an electrical block configuration, and the LEDs 27 and 28 are supplied with a constant current from a predetermined DC power source VC and emit light with a constant light intensity. PS for detection
One output current I1 of D29 is converted into a voltage signal V1 via the current-voltage conversion circuit 43, and then input to the input terminals of the adder 44 and the subtractor 45. Also, for detection P
The other output current I2 of SD29 is the current-voltage conversion circuit 46.
After being converted into the voltage signal V2 via the input terminal, the voltage signal is input to the input terminals of the adder 44 and the subtractor 45.

The divider 47 has a voltage signal VDa corresponding to the difference (I1-I2) between the detected currents supplied from the subtractor 45.
(= V1-V2) is divided by the sum (I1 + I2) of the detected currents given from the adder 44, that is, the voltage signal VTa (= V1 + V2) corresponding to the total amount of received light, and the result is output as the voltage signal VA. On the other hand, one output current I3 of the reference PSD 30 is converted into a voltage signal V3 via the current-voltage conversion circuit 48, and then input to the input terminals of the adder 49 and the subtractor 50. The other output current I4 of the reference PSD 8 is converted into a voltage signal V4 via the current-voltage conversion circuit 51, and then input to the input terminals of the adder 49 and the subtractor 50. The output terminal of the adder 49 is also connected to the rotation area detection terminal Q.

The divider 52 outputs a voltage signal VDb corresponding to the difference (I3-I4) in the detected currents supplied from the subtractor 50.
(= V3−V4) is divided by the sum (I3 + I4) of the detected currents supplied from the adder 49, that is, the voltage signal VTb (= V3 + V4) corresponding to the total amount of received light, and the result is output as the voltage signal VB. The subtracter 53 subtracts the voltage signal VB output by the divider 52 from the voltage signal VA output by the divider 47 and outputs the subtracted voltage signal VB.
To obtain a voltage signal VD (= VA-VB).

According to the above construction, the positions of the light transmitting portion 25 for detection and the light transmitting portion 26 for reference corresponding to the rotation angle θ of the rotary plate 23 are the same as in the first embodiment.
D29 and the reference PSD 30 detect each. Thereby, the rotation angle θ of the rotary plate 23 from the subtractor 53
To obtain the voltage signal VD (see FIG. 8). And
When the value of the rotation angle θ of the rotary plate 23 is in the vicinity of 0 °, the light from the LED 28 is incident on the reference PSD 30 via the identification light transmitting portion 26a of the reference light transmitting portion 26, and therefore the entire The light receiving current of increases. Therefore, since the voltage signal VTb output from the adder 49 also becomes large in this area as shown in FIG. 8, if the rotation area detection terminal Q detects this, the rotation area of the rotary plate 23 can be identified.

FIGS. 9 and 10 show a fourth embodiment of the present invention, and the portions different from the third embodiment will be described below. That is, in FIG. 9, the output terminal of the adder 49 is connected to the rotation region identification terminal Q via the comparator 54, and the reference voltage VK is applied to the reference input terminal of the comparator 54. It has become. As a result, instead of the voltage signal VTb from the adder 49 given to the rotation area identification terminal Q in the third embodiment, a comparator is provided as a digital signal S2 as shown in FIG. The output from 54 can be obtained.
As a result, the rotating area of the rotary plate 23 can be identified. Therefore, the same effect as that of the third embodiment can be obtained, and the identification can be performed digitally.

FIG. 11 shows a fifth embodiment of the present invention. Hereinafter, parts different from the first embodiment will be described. That is, this one is replaced with the identification light transmitting portion 26a provided in the reference light transmitting portion 26 in the first embodiment, and instead of FIG.
As shown in FIG. 5, the light-transmitting portions for detection 25c and 25d are formed at both ends of the light-transmitting portion for detection 25 having a width dimension wider than other portions.
Is provided. With this configuration, as in the first embodiment, the light incident on the detection PSD 29 is generated in the region where the rotation angle θ corresponding to both ends of the detection light transmitting portion 25 is near 0 °. Is controlled so as to reduce the light projection amount of the LED 27 so as to suppress the increase of the electric current.
It is possible to identify the rotation area of the above, and therefore, the same effect as that of each of the above-described embodiments can be obtained.

In each of the above embodiments, the identification light transmitting portion 26a having a width dimension larger than that of the other portions is provided as the identification light transmitting portion. However, the present invention is not limited to this.
The same effect can be obtained by forming the identification translucent portion having a width dimension smaller than that of the other portion.

Further, in each of the above embodiments, the two light emitting diodes 27 and 28 are provided as the light projecting elements so as to correspond to the detecting PSD 29 and the reference PSD 30, respectively, but the invention is not limited to this. Light may be emitted to both PSDs 29 and 30 by one light emitting diode.

Further, in each of the above-mentioned embodiments, the optical system device is not interposed between the light projecting element and the light receiving element, but an optical system device such as a lens is used if necessary. Of course, it is good.

[0063]

According to the rotation angle detecting device of the present invention, the rotation angle detecting device is capable of corresponding to the discontinuous angular positions of both ends of the light transmitting portion for detection.
Since a discriminating translucent portion having a different width dimension from the other portion is formed on either the translucent portion for detection or the translucent portion for reference of the rotating plate, the discontinuity points at both ends of the transmissive portion for detection are formed. In part,
Since the total incident light level of the light incident through the identification light projecting unit changes with respect to the incident light levels of other portions, the rotation position of the rotating plate is a discontinuous point portion (rotation angle is 0 °. Therefore, it is possible to identify the rotation angle of the rotary plate over the entire circumference of the rotary plate with a simple and inexpensive structure, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

[Figure 2] Vertical side view

FIG. 3 is an electrical block configuration diagram.

FIG. 4 is an explanatory diagram showing a signal output state.

FIG. 5 is a view corresponding to FIG. 3 showing a second embodiment of the present invention.

FIG. 6 is a view corresponding to FIG.

FIG. 7 is a view corresponding to FIG. 3 showing a third embodiment of the present invention.

FIG. 8 is a view corresponding to FIG.

FIG. 9 is a view corresponding to FIG. 3 showing a fourth embodiment of the present invention.

FIG. 10 is a view corresponding to FIG.

FIG. 11 is a view corresponding to FIG. 1 showing a fifth embodiment of the present invention.

FIG. 12 is a view corresponding to FIG. 1 showing a conventional example.

FIG. 13 is an electrical block configuration diagram.

FIG. 14 is a view corresponding to FIG.

[Explanation of symbols]

Reference numeral 21 is a rotating shaft, 23 is a rotating plate, 25 is a light transmitting portion for detection, and 2
5c, 25d, and 26a are light-transmitting parts for identification, 26 is a light-transmitting part for reference, 27 and 28 are LEDs (light projecting elements), 29 is PSD for detection (semiconductor position detecting element for detection), and 30 is reference P.
SD (reference semiconductor position detecting element), 31, 33, 3
7, 39, 43, 46, 48, 51 are current-voltage conversion circuits, 32, 38, 44, 49 are adders, 34, 45, 5
0 is a subtractor, 35 and 40 are feedback circuits, 36 is a reference voltage generation circuit, 41 is a current detection resistor, 42 and 54 are comparators, 4
7, 52 are dividers.

Claims (1)

[Claims] 1. A rotary plate attached to a rotary shaft, a reference light-transmitting portion of a constant width formed in an annular shape on the rotary plate with a predetermined radius, and the rotary plate along the circumferential direction of the rotary plate. A detection light-transmitting portion having a constant width formed in a shape in which the distance from the rotation center of the light-transmission portion is continuous, and a light-projecting element that projects light toward the reference light-transmitting portion and the detection light-transmitting portion, A reference semiconductor position detecting element that is arranged so as to face the light projecting element with the rotating plate interposed therebetween and receives light transmitted through the reference light transmitting portion and detects a light receiving position in the radial direction of the rotating plate, A semiconductor position detecting element for detection, which is arranged so as to face the light projecting element with the rotating plate interposed therebetween, receives light transmitted through the light transmitting portion for detection, and detects a light receiving position in the radial direction of the rotating plate, These reference semiconductor position detecting elements and detecting semiconductor position detecting elements Calculating means for calculating the rotation angle of the rotary plate based on the received light signal, the rotary plate corresponding to the discontinuous angular positions of both ends of the detection light-transmitting part, A rotation angle detecting device, wherein an identification light transmitting portion having a width dimension different from that of other portions is formed on either one of the detection light transmitting portion or the reference light transmitting portion.