TWI664398B - Optical rotary encoder - Google Patents

Abstract

The present invention provides an optical rotary encoder that can more accurately detect the rotation angle and the like of a rotating body without using a complicated structure. The optical rotary encoder includes: a light-emitting element 6 that emits light; a rotating plate 4 formed with a slit 41 through which light passes; a rotation plate 4 that is fixed away from the rotating plate 4 and passes through the slit when the rotating plate 4 rotates稜鏡 3, which reflects the light of 41, and a light receiving element 7A and a light receiving element 7B, which detect the light passing through the slit 41 again after being reflected by the 稜鏡 3 when the rotating plate 4 is rotated.

Description

Optical rotary encoder

The present invention relates to an optical rotary encoder that outputs a signal corresponding to a rotation displacement amount of a rotating body centered on a rotation axis.

Conventionally, in order to detect a rotation angle (rotation amount) or a rotation direction of a rotating body, a rotary encoder is widely used. There are many types of rotary encoders, such as mechanical, magnetic, and optical, and they can be used differently depending on the application or the use environment. In particular, the accuracy of an optical rotary encoder is higher than that of a mechanical or magnetic rotary encoder, and it is not affected by the surrounding magnetic field like a magnetic rotary encoder, so it is widely used.

Generally, an optical rotary encoder includes a light-emitting element that emits light, a light-receiving element that receives light, and a disc-shaped rotating plate that rotates together with a rotating body. Furthermore, the optical rotary encoder can be further classified into a transmissive type and a reflective type according to the positional relationship between the light emitting element and the light receiving element.

In a transmissive optical rotary encoder, a rotary plate having a plurality of slits is arranged between a light-emitting element and a light-receiving element which are arranged to face each other. In a transmissive rotary encoder, light emitted from a light-emitting element passes through a slit portion and then enters a light-receiving element or is shielded by a slit-free portion of a rotating plate.

On the other hand, in the reflective optical rotary encoder, a reflective region and a non-reflective region are alternately formed on one surface side of the rotary plate, and a light emitting element and a light receiving element are disposed on the other surface side. The light emitted from the light emitting element is reflected in the reflective area, or is absorbed or transmitted in the non-reflective area, and the light reflected in the reflective area is incident on the light receiving element.

The optical rotary encoder outputs a two-phase pulse signal in accordance with a change in the amount of light detected by the light receiving element. Based on this signal, the rotation angle, rotation direction, and the like of the rotating body can be detected.

For example, Patent Document 1 describes an example of a reflective optical rotary encoder. The optical rotary encoder described in Patent Document 1 includes a rotating shaft (rotating body), a light-emitting portion (light-emitting element), a light-receiving portion (light-receiving element) fixed on a circuit board, and Transparent resin rotating part (rotating plate).

In this optical rotary encoder, light projected from the light projecting section passes through the inside of the rotating section and is reflected on a reflecting surface formed on the rotating section, and is then detected by the light receiving section. In addition, if the rotating portion rotates with the rotation of the shaft, the light passing through the inside of the rotating portion becomes pulse light having a strong or weak intensity by the lens surface formed on the rotating portion, and is detected by the light receiving portion. According to the pulsed light, the amount of rotation of the shaft and the direction of rotation can be obtained. Prior Art Literature Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2000-299034 [Problems to be Solved by the Invention]

Here, in order to accurately detect the rotation angle and the like of the rotating body using a reflective optical rotary encoder, it is necessary to prevent the reflection direction of light on the reflecting surface from changing even when the rotating body is rotated.

However, in the technology described in Patent Document 1, since the movable rotating portion has a reflective surface, the direction of light reflection on the reflective surface may change. As a result, there may be cases where the rotation angle of the shaft cannot be accurately detected.

The present invention has been made to solve the above problems, and an object thereof is to provide an optical rotary encoder that can more accurately detect the rotation angle and the like of a rotating body without using a complicated structure. [Means for solving problems]

An optical rotary encoder according to the present invention includes: a light emitting element that emits light; a rotating plate having a slit formed at a peripheral portion thereof to allow the light to pass therethrough; and a rotation plate that is fixed away from the rotating plate and rotates against the rotating plate. And a light receiving element that detects the light that has passed through the slit after reflecting by the reflection portion when the rotating plate rotates, and the light that passes through the slit again. [Effect of the invention]

According to the present invention, it is possible to more accurately detect the rotation angle and the like of a rotating body without using a complicated structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of Optical Rotary Encoder] An example of a configuration of an optical rotary encoder according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of an optical rotary encoder according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof.

As shown in FIGS. 1 and 2, the optical rotary encoder of the present invention includes: a shaft body 1, a housing 2, a 稜鏡 3, a rotary plate 4, a mounting substrate 5, a light emitting element 6, a light receiving element 7A, and a light receiving element 7B.

As shown in FIG. 1, the shaft body 1 is supported by the case body 2 so that one end thereof is exposed outside the case body 2. One end of the shaft body 1 exposed to the outside of the casing 2 is connected to an arbitrary rotating body such as a motor so that the rotation axis is uniform, and the shaft body 1 rotates as the rotating body rotates.

The other end portion of the shaft body 1 is housed inside the box body 2 and is fixed to the rotating plate 4. Therefore, the rotation plate 4 is synchronized with the rotation of the rotation body by the shaft body 1, and rotates at the same rotation angle and the same rotation direction as the rotation body and the shaft body 1.

As shown in FIG. 1, the mounting substrate 5 is arranged parallel to the rotating plate 4. The mounting substrate 5 is fixed to the open end of the case 2.

A light-emitting element 6 and two light-receiving elements 7A and 7B are provided on a surface (referred to as a mounting surface) of the mounting substrate 5 facing the rotating plate 4. As shown in FIG. 1, the light-emitting element 6, the light-receiving element 7A, and the light-receiving element 7B are arranged at positions on the mounting surface that are offset from the rotation axis of the shaft body 1.

The light emitting element 6 is, for example, a light emitting diode (LED), and includes a lens (not shown). The light emitted by the LED is converted into parallel light having a predetermined beam diameter by a lens and emitted. The light emitting element 6 emits the parallel light in the direction of the rotating plate 4.

The light-receiving element 7A and the light-receiving element 7B are, for example, light sensors such as a photodiode or a photoelectric crystal, and generate a signal corresponding to the amount of received light. The light-receiving element 7A and the light-receiving element 7B further include a signal processing circuit including an amplifier circuit or a waveform shaping circuit, and the signal processing circuit generates and outputs a pulse signal corresponding to the amount of received light.

A connector 8 is disposed on a surface of the mounting substrate 5 opposite to the surface on which the light-emitting element 6 and the light-receiving element 7A and the light-receiving element 7B are mounted. The connector 8 is used to supply power to the light-emitting element 6 and to the light-emitting element 6, for example. Input signals are transmitted, and pulse signals output by the light receiving elements 7A and 7B are transmitted to the outside of the optical rotary encoder.

Further, a plurality of slits 41 through which light can pass are formed in the rotating plate 4. The slits 41 have, for example, a fan shape, a trapezoidal shape, or a fan trapezoidal shape, and are arranged on the rotary plate 4 at a radial interval. The width of the slit 41 is formed at least wider than the beam diameter of the light emitted from the light emitting element 6. The number of the slits 41 can be appropriately determined according to the resolution required by the optical rotary encoder.

In the rotary plate 4, portions other than the slit 41 shield the light emitted from the light emitting element 6. The rotating plate 4 is preferably formed of a material that does not scatter light as much as possible. Thereby, the light emitted from the light emitting element 6 can be prevented from being scattered by the portion other than the slit 41 of the rotating plate 4 and detected by the light receiving element 7A and the light receiving element 7B.

The rotating plate 4 is rotatably fixed to an end portion of the shaft body 1. Further, as shown in FIG. 1, the inner wall surface of the box 2 facing the shaft body 1 side of the rotating plate 4 is fixed with a 稜鏡 3 for reflecting light emitted from the light emitting element 6. The box 2 is provided with a cutout portion according to the shape of the 稜鏡 3, and the 稜鏡 3 is fitted into the cutout.

FIG. 3 is a perspective view for explaining 稜鏡 3. As shown in FIG. 3, 稜鏡 3 has a structure in which, for example, side surfaces of two right-angled 稜鏡 31 and right-angled 稜鏡 32 are shifted by a predetermined distance in a direction parallel to the bottom surface (a surface opposed to a right-angled edge), and fit.

The two oblique surfaces of the right angle 稜鏡 31 and the right angle 稜鏡 32 that sandwich the right angle edge reflect light incident from the bottom surface thereof, and convert the direction of the light into a direction opposite to the incident direction.

Furthermore, when the two right-angled 稜鏡 31 and right-angled 稜鏡 32 are bonded together, the staggered distance is adjusted to the following distance: so that the light emitted from the light-emitting element 6 is reflected by 入射 3 and can be accurately incident on the light-receiving element 7A, Light receiving element 7B.

Alternatively, a right-angled 稜鏡 mirror, in which a metal film or the like is vapor-deposited on the two inclined surfaces with the right-angled edges, may be used instead of the two right-angled 稜鏡 31 and right-angled 稜鏡 32.

稜鏡 3 is fixed to the light-emitting element 6, the light-receiving element 7A, and the upper portion of the light-receiving element 7B.

In the present embodiment, the vertical direction of the optical rotary encoder is defined by the vertical direction in FIG. 1. However, the up-down direction is an up-down direction assumed for explanation, and the up-down direction of the optical rotary encoder is not limited to this.

FIG. 4A is a diagram for explaining a positional relationship between the light emitting element 6, the light receiving element 7A, and the light receiving element 7B. FIG. 4B is a diagram for explaining the positional relationship between the right angle 稜鏡 31, the right angle 稜鏡 32, and the light emitting element 6, the light receiving element 7A, and the light receiving element 7B. In FIGS. 4A and 4B, each part such as the light-emitting element 6 is projected on a projection plane perpendicular to the rotation axis of the rotation plate 4.

FIG. 4A shows the horizontal positional relationship between the light emitting element 6 and the two light receiving elements 7A and 7B. As shown in FIG. 4A, the light-emitting element 6, the light-receiving element 7A, and the light-receiving element 7B are arranged, for example, on a line 1-1 ′ in the order of one light-receiving element 7A, the light-emitting element 6, and the other light-receiving element 7B. Mounting surface of the substrate 5.

Here, the straight line L-L ′ shown in FIGS. 4A and 4B indicates a straight line passing through the arrangement position of the light emitting element 6 and the rotation axis of the rotating plate 4 on the projection plane. In this embodiment, the straight line 1-1 'is not parallel to the straight line L-L', but is inclined to the straight line L-L 'at a predetermined angle α.

The details will be described below. By arranging the light-emitting element 6 and the two light-receiving elements 7A and 7B in this way, the timing of detecting light by the two light-receiving elements 7A and 7B is different, so that each light-receiving element 7A can be made different. The pulse signal output from the light receiving element 7B causes a phase difference.

FIG. 4B shows the positional relationship between the right angle 稜鏡 31 and the right angle 稜鏡 32, the light emitting element 6, the light receiving element 7A, and the light receiving element 7B.

As shown in FIG. 4B, on the projection surface, the light-emitting element 6 is disposed at a position overlapping the joint surface of the two right-angled corners 31 and 32. This case indicates that a part of the light having a predetermined beam diameter emitted from the light emitting element 6 is incident on two right angles 稜鏡 31 and right angles 稜鏡 32, respectively.

In addition, in FIG. 4B, the shapes of the bottom surfaces of the right-angled 稜鏡 31 and the right-angled 梯形 32 are shown in a trapezoid, but this is an example, and other shapes such as a parallelogram may be used.

FIG. 5A and FIG. 5B are diagrams for explaining light paths when light emitted from the light-emitting element 6 is incident from the bottom surface side to two right angles 稜鏡 31, right angles 稜鏡 32, and right angles 侧 32 .

As described above, the light incident from the bottom surface sides of the right angle 稜鏡 31 and the right angle 稜鏡 32 has a predetermined beam diameter. As shown in FIG. 5A, the case where the light 101 having a predetermined beam diameter is incident on the joint surface of the two right-angled 稜鏡 31 and right-angled 稜鏡 32 indicates that light having half the amount of light 101 is incident on the two right-angled Right angle 稜鏡 32.

Further, as shown in FIG. 5B, the light incident on each of the right-angled 稜鏡 31 and the right-angled 前进 32 proceeds straight in the right-angled 稜鏡 31 and the right-angled 稜鏡 32 and reaches the respective reflection surfaces. Thereafter, the light is reflected by the reflecting surface, the light 102 advances within the right angle 稜鏡 31, and the light 103 advances within the right angle 稜鏡 32. Then, the light 102 and the light 103 advancing in the right angle 稜鏡 31 and the right angle 到达 32 reach the other reflecting surface, and then change their directions to become the light 104 and the light 105 which proceed in the direction opposite to the incident parallel light 101.

In the optical rotary encoder of the present embodiment, the reflection directions of the respective reflection surfaces of the right angle 稜鏡 31 and the right angle 稜鏡 32 are adjusted so that the light 104 and the light 105 enter the two light receiving elements 7A and 7B, respectively.

Next, an operation example of the optical rotary encoder will be described in detail.

When the rotating body such as a motor rotates, the shaft body 1 connected to the rotating body, and the rotating plate 4 fixed to the end of the shaft body 1 rotate around the rotating shaft of the rotating body in the same manner as the rotating body.

Here, the light emitting element 6 disposed on the mounting substrate 5 at a position deviated from the rotation axis emits light having a predetermined beam diameter. When the rotating plate 4 having the slit 41 rotates, light emitted from the light emitting element 6 passes through the slit 41 or is blocked by the rotating plate 4.

The light passing through the slit 41 is incident on the right angle 稜鏡 31 and the right angle 稜鏡 32 fixed to the inner wall surface of the box 2. After that, the light is reflected by the reflection surfaces of the right angle 稜鏡 31 and the right angle 稜鏡 32, and passes through the slit 41 again, and then enters the light receiving element 7A and the light receiving element 7B.

The light-receiving element 7A and the light-receiving element 7B output a pulse signal corresponding to the amount of received light in accordance with the rotation of the rotary plate 4. By analyzing the pulse signal, the rotation angle and direction of rotation of the rotating body can be detected.

6A to 6E are diagrams for explaining the movement of the slit 41 as the rotation plate 4 rotates. 4A, FIG. 4B, and FIG. 5A, FIG. 6A to FIG. 6E show the positional relationship of each part when the optical rotary encoder is viewed from above.

FIG. 7 is a diagram showing an example of an output signal that is output by the light receiving element 7A and the light receiving element 7B as the slit 41 shown in FIGS. 6A to 6E is moved. The output signal A indicates the output signal of one light receiving element 7A, and the output signal B indicates the output signal of the other light receiving element 7B.

In FIGS. 6A to 6E, light is emitted from the light emitting element 6 in a near vertical direction on the paper surface. Then, as the rotation plate 4 rotates, the slit 41 moves in the rotation direction R. The light-emitting element 6 and the two light-receiving elements 7A and 7B are arranged on a line 1-1 'inclined at an angle α to the line L-L'. Therefore, the light-receiving element 7A enters before the light-emitting element 6 and light-receiving element 7B Inside the frame of the slit 41.

FIG. 6A shows the positional relationship of each part at time T1 immediately before the light receiving element 7A enters the frame of the slit 41. At this point in time, the light-emitting element 6 has not yet entered the frame of the slit 41, and therefore, the light emitted by the light-emitting element 6 is shielded by the rotating plate 4 and does not reach 稜鏡 3. Therefore, as shown at time T1 in FIG. 7, at this point in time, the output signal A and the output signal B of either of the two light receiving elements 7A and 7B are at a low level.

FIG. 6B shows the positional relationship of each part at time T2 when the light-emitting element 6 starts to enter the frame of the slit 41 after time has elapsed in FIG. 6A. At this point in time, the light emitted from the light emitting element 6 starts to pass through the slit 41. The light passing through the slit 41 is reflected by the 稜鏡 3 as described above, passes through the slit 41 again, and then enters the light receiving element 7A. Therefore, as shown in FIG. 7, at time T2, the output signal A of the light receiving element 7A becomes a high level.

Furthermore, at this point in time, the light receiving element 7B has not entered the frame of the slit 41, so as shown in FIG. 7, at time T2, the output signal B of the light receiving element 7B is still at a low level.

FIG. 6C shows the positional relationship of each part at time T3 when the light receiving element 7B starts to enter the frame of the slit 41 after a further elapse of time. At this point in time, the light-emitting element 6 and the two light-receiving elements 7A and 7B all enter the frame of the slit 41, so the reflected light from 稜鏡 3 starts to enter both the light-receiving element 7A and the light-receiving element 7B. As shown in FIG. 7, at time T3, the output signal A and the output signal B of both the light receiving element 7A and the light receiving element 7B are at a high level.

FIG. 6D shows the positional relationship of each part at time T4 when the light receiving element 7A starts to leave the frame of the slit 41 after further elapse of time. At this point in time, the reflected light toward the light receiving element 7A starts to be blocked by the rotating plate 4. On the other hand, the light-emitting element 6 and the light-receiving element 7B are still in the frame of the slit 41. Therefore, the light emitted from the light-emitting element 6 and the reflected light toward the light-receiving element 7B are not shielded by the rotating plate 4 and are incident on the light-receiving element 7B. . Therefore, as shown in FIG. 7, at time T4, the output signal B of the light receiving element 7B is maintained at a high level, but the output signal A of the light receiving element 7A is at a low level.

FIG. 6E shows the positional relationship of each portion at time T5 when the light emitting element 6 starts to leave the frame of the slit 41 after a further elapse of time. At this point in time, the light emitted from the light emitting element 6 starts to be shielded by the rotating plate 4. Therefore, as shown in FIG. 7, at time T5, the output signal A and the output signal B of any of the light receiving element 7A and the light receiving element 7B are both Become low.

After the time T5, as the rotating plate 4 rotates, the output signals of either the light receiving element 7A or the light receiving element 7B remain at a low level until the light emitting element 6 enters the frame of the next slit. Furthermore, thereafter, the same phenomenon as described above with reference to FIGS. 6A to 6E and FIG. 7 occurred repeatedly.

The arrangement direction of the light-emitting element 6, the light-receiving element 7A, and the light-receiving element 7B can be appropriately set. This direction is defined by the angle α formed by the straight line 1-1 'and the straight line L-L'. 6A to 6E, if the angle α becomes larger, it is necessary to increase the width of the slit 41. The width of the slit 41 is also limited by the size of the rotating plate 4 or the number of slits. Therefore, the size of the angle α may be appropriately set according to these parameters and the like.

As described above, the optical rotary encoder of this embodiment includes: a light emitting element 6 that emits light; a rotating plate 4 formed with a slit 41 through which light passes through the peripheral portion; and fixed and separated from the rotating plate 4 The light receiving element 7A and the light receiving element 7B which detect the light reflected through the slit 41 when the rotating plate 4 rotates, and the light that passes through the slit 41 and reflects again after the rotating plate 4 rotates.

In this way, by fixing 稜鏡 3 and the movable rotating plate 4 separately, the possibility of the light reflection direction changing on the reflecting surface can be eliminated, so that the rotating body can be detected more accurately without using a complicated structure. Rotation angle, etc.

In the optical rotary encoder of the present embodiment, the two right-angled 稜鏡 31 and right-angled 稜鏡 32 reflect light emitted from the light-emitting element 6 so as to be incident on the two light-receiving elements 7A and 7B, respectively.

Thereby, the number of parts of the optical rotary encoder can be reduced, and the optical rotary encoder can be easily manufactured. As a result, the manufacturing cost of the optical rotary encoder can be suppressed.

Further, in the optical rotary encoder of this embodiment, the light receiving elements 7A and 7B are arranged in such a manner that the positions of the light receiving elements 7A and 7B are projected on the projection perpendicular to the rotation axis of the rotary plate 4 When the projection plane having the arrangement position of the light-emitting element 6 is located, the straight line 1-1 'passing through the arrangement position of the light-receiving element 7A, the light-receiving element 7B, and the arrangement position of the light-emitting element 6 The straight line L-L 'is inclined at a predetermined angle.

Thereby, a two-phase pulse signal can be easily obtained, and based on the pulse signal, a rotation angle, a rotation direction, and the like of a rotating body can be easily detected. Although detailed description will be given below, the slit width can be reduced compared to the case where the light emitting element 6, the light receiving element 7A, and the light receiving element 7B are arranged in a radial direction. Therefore, the number of pulses can be further increased to improve the detection accuracy of the rotation angle.

Moreover, at this time, the distance between the light-emitting element 6 and the light-receiving element 7A and the light-receiving element 7B can be extended. Therefore, the light emitted from the light-emitting element 6 can be suppressed from being directly detected by the light-receiving element 7A and the light-receiving element 7B without passing through the slit 41. The effect of crosstalk. Therefore, the rotary plate 4 can be reduced, and the optical rotary encoder can be miniaturized.

Furthermore, the optical rotary encoder of this embodiment further includes a case 2 that houses the light-emitting element 6, the rotary plate 4, 稜鏡 3, the light-receiving element 7A, and the light-receiving element 7B. The inner wall surface of the case 2 has a notch,稜鏡 3 is arranged in the cutout portion.

Thereby, the cymbal 3 is half-embedded in the inner wall surface of the box body 2, and the installation space of the cymbal 3 can be easily secured. In addition, it is possible to reduce the size or thickness of the optical rotary encoder.

In addition, the optical rotary encoder described above is only one embodiment of the present invention, and the present invention is not limited to the embodiment. Hereinafter, modification examples of the embodiments of the present invention will be described in detail.

[Modification 1] In the optical rotary encoder according to the embodiment described above, the light-emitting element 6 and the two light-receiving elements are arranged so that the straight line 1-1 'is inclined at a predetermined angle α to the straight line L-L'. 7A and light receiving element 7B. However, in the present invention, the light-emitting element 6 and the two light-receiving elements 7A and 7B may be arranged on a straight line L-L '.

In the first modification, in order to obtain a two-phase pulse signal, the shape of the slit 41 of the rotary plate 4 is changed to a shape different from that of the above-mentioned embodiment, so that light is applied to the two light receiving elements 7A and 7B. There are differences in incident timing. FIG. 8 is a diagram illustrating a shape of a slit in a first modification of the present invention.

As shown in FIG. 8, in the first modification, a slit 41 ′ is formed in the rotating plate 4. The slit 41 'has a shape in which the slit 41'A and the slit 41'B partially overlap each other. The slit 41'A is a slit capable of incorporating the light emitting element 6 and the light receiving element 7A into the frame, and the slit 41'B is a slit capable of incorporating the light emitting element 6 and the light receiving element 7B into the frame.

When the rotating plate 4 rotates, the light emitting element 6 and the light receiving element 7A first enter the frame of the slit 41'A. At this time, the light emitted from the light-emitting element 6 passes through the slit 41'A, is reflected by the 稜鏡 3, and enters the light-receiving element 7A. At this point in time, the light receiving element 7B does not enter the frame of the slit 41 ′, so light does not enter the light receiving element 7B.

When the rotating plate 4 is further rotated, the light receiving element 7B enters the frame of the slit 41'B, and light can be detected by both the light receiving element 7A and the light receiving element 7B.

If the rotating plate 4 is further rotated, the light receiving element 7A will leave the frame of the slit 41'A, but the light emitting element 6 and the light receiving element 7B remain in the frame of the slit 41'B, so only the light receiving element 7B Light for detection.

With the shape of the slit 41 ′, the incident timings of the light incident on the two light receiving elements 7A and 7B are different, and a two-phase pulse signal can be obtained.

In the optical rotary encoder of the first modification, by fixing the 稜鏡 3 to the movable rotary plate 4 in the same manner as in the above embodiment, it is possible to eliminate the possibility that the reflection direction of the light on the reflecting surface changes. This makes it possible to more accurately detect the rotation angle of a rotating body without using a complicated structure.

[Modification 2] In the optical rotary encoder according to the embodiment, the light emitted from the light-emitting element 6 is reflected by 稜鏡 3. However, in the present invention, for example, a reflective film may be used instead of 稜鏡 3 to reflect light.

FIG. 9 is a diagram showing a modified example in which a reflecting film 9 is provided instead of the 稜鏡 3. As shown in FIG. 9, a reflective film 9 is provided on the inner wall surface of the housing 2 facing the light-emitting element 6, the light-receiving element 7A, and the light-receiving element 7B. The reflection film 9 can be formed on the inner wall surface by vapor deposition of a metal film or the like. Furthermore, a reflecting plate may be provided on the inner wall surface instead of the reflecting film 9.

The reflection film 9 or the reflection plate has, for example, the same shape as the two inclined surfaces of the right-angled ridge 31 and the right-angled ridge 32 described in the above embodiment with the right-angled edges interposed therebetween. Thereby, similarly to the said embodiment, the reflective film 9 or the reflective plate can reflect the light from the light emitting element 6 so that it may enter the light receiving element 7A and the light receiving element 7B.

In such an optical rotary encoder according to Modification 2 of the present invention, as in the above-mentioned embodiment, the reflective film 9 or the reflective plate is fixed apart from the movable rotary plate 4 so that the reflective film 9 can be eliminated. Or the possibility that the reflection direction of the light on the reflecting plate may change, it is possible to more accurately detect the rotation angle of the rotating body without using a complicated structure.

[Modification 3] In the optical rotary encoder according to the embodiment, the shaft body 1 is rotatably supported by the case body 2. However, in the present invention, a hollow shaft may be provided instead of the shaft body 1, and the hollow shaft and the rotating body may be connected. This makes it possible to further reduce the size of the optical rotary encoder.

Further, in the optical rotary encoder of the above-mentioned embodiment, a connector 8 is disposed on the mounting substrate 5 on a surface opposite to the surface on which the light-emitting element 6, the light-receiving element 7A, and the light-receiving element 7B are mounted. Power is supplied through the connector 8 or signal input / output is performed with the outside. However, in the present invention, a pin terminal for through-hole mounting, a plate terminal for surface mounting, or a lead wire may be provided instead of the connector 8 to supply power or input and output signals to and from the outside.

1‧‧‧ shaft

2‧‧‧ box

3‧‧‧ 稜鏡

4‧‧‧ rotating plate

5‧‧‧Mounting base

6‧‧‧light-emitting element

7A, 7B ‧‧‧ light receiving element

8‧‧‧ connector

9‧‧‧ reflective film

31, 32‧‧‧ Right-angled 稜鏡

41, 41 ', 41'A, 41'B‧‧‧Slits

101, 102, 103, 104, 105‧‧‧ light

A, B‧‧‧ output signal

l-l ', L-L'‧‧‧ straight

R‧‧‧ Direction of rotation

T1 ~ T5‧‧‧time

α‧‧‧ angle

FIG. 1 is a cross-sectional view of an optical rotary encoder according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the optical rotary encoder according to the embodiment of the present invention. FIG. 3 is a diagram for explaining 稜鏡. FIG. 4A is a diagram for explaining a positional relationship between a light emitting element and a light receiving element. FIG. 4B is a diagram for explaining a positional relationship between a right angle 稜鏡 and a light emitting element and a light receiving element. FIG. 5A is a diagram for explaining a light path of light incident from the bottom surface side in a ridge. FIG. FIG. 5B is a diagram for explaining a light path of light incident from the bottom surface side within the frame. FIG. FIG. 6A is a diagram for explaining movement of a slit according to rotation of a rotating plate. FIG. 6B is a diagram for explaining movement of a slit according to rotation of a rotating plate. FIG. 6C is a diagram for explaining movement of a slit in accordance with rotation of a rotating plate. FIG. 6D is a diagram for explaining movement of a slit in accordance with rotation of a rotating plate. FIG. 6E is a diagram for explaining movement of a slit in accordance with rotation of a rotating plate. FIG. 7 is a diagram showing an example of a pulse signal output by a light receiving element as the slit moves. FIG. 8 is a diagram illustrating a shape of a slit in a modification of the present invention. FIG. 9 is a diagram showing a modified example in which a reflective film is provided instead of chirp.

Claims (4)

An optical rotary encoder includes: a light-emitting element that emits light; a rotating plate having a slit formed at a peripheral portion thereof to pass the light; a reflecting portion that is fixed away from the rotating plate and opposite to the rotating plate; The light passing through the slit is reflected when the rotating plate rotates; and the light receiving element detects the light passing through the slit again after being reflected by the reflecting portion when the rotating plate is rotated, wherein the light receiving element is It is configured in such a manner that when the arrangement position of the light receiving element and the arrangement position of the light emitting element are projected on a projection plane perpendicular to the rotation axis of the rotating plate, the arrangement position of the light receiving element and the light emission pass through. The straight line of the arrangement position of the element is inclined at a predetermined angle with respect to the straight line passing through the rotation axis and the arrangement position of the light emitting element. The optical rotary encoder according to item 1 of the scope of patent application, wherein the reflecting portion includes two chirps, and each of the chirps causes light emitted from the light emitting element to be incident on two of the light receiving elements, respectively. Element way reflection. The optical rotary encoder according to item 1 of the patent application scope, further comprising a box housing the light emitting element, the rotating plate, the reflecting portion, and the light receiving element, and an inner wall surface of the box. It has a notch portion, and the reflection portion is disposed on the notch portion. The optical rotary encoder according to item 1 of the scope of patent application, wherein the reflection portion is a reflection film or a reflection plate that reflects light.