Optical encoder

Abstract

The objective is to improve the detection accuracy of the origin of a rotating disk in an optical encoder having a fixed slit pattern for the Z phase and a fixed slit pattern for the inverted Z phase for origin detection. [Solution] The optical encoder comprises a Z1 phase pattern section and a Z2 phase pattern section for origin detection provided on a rotating disk, a Z1 phase fixed slit section 53 provided opposite the Z1 phase pattern section, and a Z2 phase fixed slit section 54 provided opposite the Z2 phase pattern section 34. In the direction along the circumferential direction of the rotating disk, the arrangement order of the patterns in the Z2 phase fixed slit section 54 is configured in the opposite direction to the arrangement order of the patterns in the Z1 phase fixed slit section 53.

Description

Technical Field

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[0003]

[0001] This invention relates to an optical encoder, particularly an incremental optical encoder.

Background Art

[0002] There is known an optical encoder including a rotating disk having a pattern formed by arranging slits and a fixed slit having a pattern formed by arranging slits, wherein light emitted from a light emitting element is received by a light receiving element through the patterns of the rotating disk and the fixed slit, and the rotation angle of the rotating disk is detected based on the optical signal output from the light receiving element.

[0003] The optical encoder described in Patent Document 1 has a Z phase and an inverted Z phase as phases for detecting the origin of the rotating disk. The rotating disk is provided with a Z-phase slit pattern and an inverted Z-phase slit pattern for origin detection, and the fixed slit is provided with a Z-phase slit pattern and an inverted Z-phase slit pattern for origin detection. The Z-phase slit pattern and the inverted Z-phase slit pattern of the fixed slit have the same pattern in the direction along the circumferential direction of the rotating disk. [[ID=D18]]

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the optical encoder described in Patent Document 1, when the Z-phase slit pattern of the fixed slit and the inverted Z-phase slit pattern are arranged adjacent to each other in a direction along the radial direction of the rotating disk, crosstalk occurs from the light-transmitting portions of the slit patterns, which reduces the accuracy of detecting the origin of the rotating disk.

[0006] This invention was made to solve these problems, and aims to improve the accuracy of detecting the origin of a rotating disk in an optical encoder having a fixed slit pattern for the Z phase and a fixed slit pattern for the inverted Z phase for origin detection. [Means for solving the problem]

[0007] The optical encoder according to this invention includes a rotating disk rotatably mounted together with a rotating shaft, a rotation detection pattern section provided on the rotating disk for detecting the rotation angle and direction of rotation of the rotating disk, a first origin detection pattern section and a second origin detection pattern section provided on the rotating disk for detecting the origin of the rotating disk, a rotation detection fixed slit section having a pattern including a light-transmitting section, provided opposite the rotation detection pattern section, a first origin detection fixed slit section having a pattern including a light-transmitting section, provided opposite the first origin detection pattern section, and provided opposite the second origin detection pattern section The device comprises a second origin detection fixed slit section having a pattern including a light-transmitting section, a light-emitting element that emits light to illuminate the rotation detection pattern section, the first origin detection pattern section, and the second origin detection pattern section, a rotation detection light-receiving element that transmits or reflects the rotation detection pattern section and receives light that has been transmitted through the rotation detection fixed slit section, a first origin detection light-receiving element that transmits or reflects the first origin detection pattern section and receives light that has been transmitted through the first origin detection fixed slit section, and a second origin detection light-receiving element that transmits or reflects the second origin detection pattern section and receives light that has been transmitted through the second origin detection fixed slit section, wherein the second origin detection pattern section is The first origin detection pattern section is provided adjacent to the rotating disk along the radial direction,The second origin detection pattern section has a pattern that is inverted with respect to the first origin detection pattern section, and in the direction along the circumferential direction of the rotating disk, the arrangement order of the patterns in the second origin detection pattern section is configured in the opposite direction to the arrangement order of the patterns in the first origin detection pattern section. The second origin detection fixing slit portion is provided adjacent to the first origin detection fixing slit portion along the radial direction of the rotating disk. In the direction along the circumferential direction of the rotating disk, the arrangement order of the patterns in the second origin detection fixed slit section is configured in the opposite direction to the arrangement order of the patterns in the first origin detection fixed slit section.

[0008] Furthermore, the first origin detection fixed slit portion and the second origin detection fixed slit portion may be configured symmetrically with respect to each other in the direction along the circumferential direction of the rotating disk. Furthermore, the rotation detection pattern section, the first origin detection pattern section, and the second origin detection pattern section may include a translucent pattern formed on the rotating disk. Furthermore, the rotation detection pattern section, the first origin detection pattern section, and the second origin detection pattern section may include a reflection pattern formed on the surface of the rotating disk. [Effects of the Invention]

[0009] According to this invention, in the direction along the circumferential direction of the rotating disk, the arrangement order of the patterns of the second origin detection fixed slit portion of the fixed slit portion of the optical encoder is configured in the opposite direction to the arrangement order of the patterns of the first origin detection fixed slit portion. Therefore, in an optical encoder having a first origin detection fixed slit portion pattern and a second origin detection fixed slit portion pattern for origin detection, the accuracy of detecting the origin of the rotating disk can be improved. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an optical encoder according to an embodiment. [Figure 2] Figure 1 is a schematic diagram of the Z1 phase pattern section and the Z2 phase pattern section of the rotating disk shown. [Figure 3] Figure 1 is a schematic diagram of the Z1 phase fixed slit portion and the Z2 phase fixed slit portion of the fixed slit plate shown. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 is a schematic diagram of an optical encoder according to this embodiment. The optical encoder 1 is an incremental optical encoder and comprises a rotating shaft 20 connected to an object to be measured, and a rotating disk 30 rotatably mounted together with the rotating shaft 20. The body of the rotating disk 30 is made of a transparent material that transmits light, such as glass or resin. On the radially outer side of the rotating disk 30, there is an A-phase B-phase pattern section 31 on the transparent disk surface, in which a light-blocking pattern is arranged in a ring shape at equal angular intervals in the circumferential direction. The A-phase B-phase pattern section 31 is used to detect the rotation angle and rotation direction of the rotating shaft 20. The A-phase B-phase pattern section 31 constitutes a rotation detection pattern section.

[0012] Furthermore, radially inward from the A-phase and B-phase pattern section 31 of the rotating disk 30, there are Z1-phase pattern section 33 and Z2-phase pattern section 34, in which a light-shielding pattern, which is a pattern of pseudo-random codes, is arranged circumferentially on the transparent disk surface. The Z2-phase pattern section 34 is provided adjacent to the radially inward side of the Z1-phase pattern section 33. The Z1-phase pattern section 33 and Z2-phase pattern section 34 are used for origin detection of the rotating disk 30. The Z2-phase is the inverted Z-phase with respect to the Z1-phase. The Z1-phase pattern section 33 constitutes the first origin detection pattern section, and the Z2-phase pattern section 34 constitutes the second origin detection pattern section.

[0013] A light-emitting diode 40 is provided on one side of the rotating disk 30 to illuminate the rotating disk 30. The light-emitting diode 40 includes an A-phase light-emitting diode 41 that emits light to illuminate the A-phase and B-phase pattern section 31, a B-phase light-emitting diode 42 that is provided circumferentially spaced away from the A-phase light-emitting diode 41 and emits light to illuminate the A-phase and B-phase pattern section 31, and a Z-phase light-emitting diode 43 that emits light to illuminate the Z1-phase pattern section 33 and the Z2-phase pattern section 34. The A-phase light-emitting diode 41 and the B-phase light-emitting diode 42 face the A-phase and B-phase pattern section 31, and the Z-phase light-emitting diode 43 faces the Z1-phase pattern section 33 and the Z2-phase pattern section 34. The A-phase light-emitting diode 41, the B-phase light-emitting diode 42, and the Z-phase light-emitting diode 43 constitute a light-emitting element.

[0014] On the other side of the rotating disk 30, a fixed slit plate 50 is provided, which is fixedly installed within the optical encoder 1. The fixed slit plate 50 is made of a light-impermeable material, such as metal. The fixed slit plate 50 has an A-phase fixed slit portion 51 and a B-phase fixed slit portion 52, which are provided opposite the A-phase and B-phase pattern portions 31 of the rotating disk 30. The A-phase fixed slit portion 51 faces the A-phase light-emitting diode 41 across the rotating disk 30, and the B-phase fixed slit portion 52 faces the B-phase light-emitting diode 42 across the rotating disk 30. The A-phase fixed slit portion 51 and the B-phase fixed slit portion constitute a rotation detection fixed slit portion.

[0015] Furthermore, the fixed slit plate 50 has a Z1 phase fixed slit portion 53 that is provided so as to be able to face the Z1 phase pattern portion 33 of the rotating disk 30, and a Z2 phase fixed slit portion 54 that is provided so as to be able to face the Z2 phase pattern portion 34. That is, the Z2 phase fixed slit portion 54 is provided adjacent to the Z1 phase fixed slit portion 53 in the radially inward direction of the rotating disk 30. The Z1 phase fixed slit portion 53 constitutes the first origin detection fixed slit portion, and the Z2 phase fixed slit portion 54 constitutes the second origin detection fixed slit portion.

[0016] Furthermore, a phototransistor 60 is provided on the other side of the rotating disk 30, sandwiching a fixed slit plate 50. The phototransistor 60 includes an A-phase phototransistor 61 that receives light transmitted through the A-phase fixed slit portion 51, a B-phase phototransistor 62 provided circumferentially separated from the A-phase light-emitting diode and receiving light transmitted through the B-phase fixed slit portion 52, a Z1-phase phototransistor 63 that receives light transmitted through the Z1-phase pattern portion 32, and a Z2-phase phototransistor 64 that receives light transmitted through the Z2-phase pattern portion 33. The A-phase phototransistor 61 and the B-phase phototransistor 62 constitute a rotation detection light-receiving element, the Z1-phase phototransistor 63 constitutes a first origin detection light-receiving element, and the Z2-phase phototransistor 64 constitutes a second origin detection light-receiving element.

[0017] The A-phase phototransistor 61 faces the A-phase light-emitting diode 41, with the A-phase fixed slit portion 51 and the A-phase B-phase pattern portion 31 of the rotating disk 30 in between. The A-phase phototransistor 61 receives light that is illuminated from the A-phase light-emitting diode 41 and passes through the A-phase B-phase pattern portion 31 and the A-phase fixed slit portion 51. The B-phase phototransistor 62 faces the B-phase light-emitting diode 42, with the B-phase fixed slit portion 52 and the A-phase B-phase pattern portion 31 of the rotating disk 30 in between. The B-phase phototransistor 62 receives light that is illuminated from the B-phase light-emitting diode 42 and passes through the A-phase B-phase pattern portion 31 and the B-phase fixed slit portion 52. The A-phase fixed slit portion 51 and the B-phase fixed slit portion 52 are arranged such that the output phase difference between the output signal of the A-phase phototransistor 61 and the output signal of the B-phase phototransistor 62 is 90 degrees.

[0018] The Z1-phase phototransistor 63 can face the Z-phase light-emitting diode 43 with the Z1-phase fixed slit portion 53 and the Z1-phase pattern portion 33 interposed therebetween, and the Z2-phase phototransistor 64 can face the Z-phase light-emitting diode 43 with the Z2-phase fixed slit portion 54 and the Z2-phase pattern portion 34 interposed therebetween. That is, the Z2-phase phototransistor 64 is provided adjacent to the Z1-phase phototransistor 63 in the radially inner direction of the rotating disk 30. The Z1-phase phototransistor 63 receives the light irradiated from the Z-phase light-emitting diode 43 and transmitted through the Z1-phase pattern portion 33 and the Z1-phase fixed slit portion 53. The Z2-phase phototransistor 64 receives the light irradiated from the Z-phase light-emitting diode 43 and transmitted through the Z1-phase pattern portion 34 and the Z2-phase fixed slit portion 54.

[0019] FIG. 2 is a schematic view of the Z1-phase pattern portion 33 and the Z2-phase pattern portion 34 of the rotating disk 30 shown in FIG. 1. The rotating disk 30 is formed of a transparent material that transmits light, and a Z1-phase pattern portion 33, which is a light-shielding pattern of the Z1 phase, and a Z2-phase pattern portion 34, which is a light-shielding pattern of the Z2 phase, are provided on the surface. The Z1-phase pattern portion 33 is a light-shielding pattern composed of a light-shielding portion 33a where a light-shielding member is provided on the surface of the transparent rotating disk 30 and a light-transmitting portion 33b where no light-shielding member is provided. Further, the Z2-phase pattern portion 34 is a light-shielding pattern composed of a light-shielding portion 34a where a light-shielding member is provided on the surface of the rotating disk 30 and a light-transmitting portion 34b where no light-shielding member is provided. The Z2-phase pattern portion 34 is provided adjacent to the Z1-phase pattern portion 33 and radially inward. In FIG. 2, the light-shielding portion is shown by hatching.

[0020] The Z1-phase pattern portion 33 represents a 4-bit bit pattern. Among the light-shielding patterns, the light-transmitting portion 33b represents the bit value 1, and the light-shielding portion 33a represents the bit value 0. In the Z1-phase pattern portion 33, the light-shielding portion 33a and the light-transmitting portion 33b are arranged in the order of "1011" along the clockwise direction (CW) of the rotating disk 30 indicated by the arrow A to represent a 4-bit bit pattern.

[0021] The Z2-phase pattern portion 34 represents a 4-bit bit pattern. Also, since the Z2 phase is the inverted Z1 phase, the bit values represented by the light-transmitting portion 33b and the light-blocking portion 33a in the Z2-phase pattern portion 34 are inverted from those in the Z1-phase pattern portion 33. The light-transmitting portion 33b represents bit value 0, and the light-blocking portion 33a represents bit value 1. In the Z2-phase pattern portion 34, the light-blocking portion 33a and the light-transmitting portion 33b are arranged along the counterclockwise (CCW) direction indicated by arrow B to represent a 4-bit bit pattern in the order of "1011". That is, in the circumferential direction of the rotating disk 30, the Z2-phase pattern portion 34 is configured such that the order of the bits in the bit pattern is reversed with respect to the Z1-phase pattern portion 33.

[0022] FIG. 3 is a schematic diagram of the Z1-phase fixed slit portion 53 and the Z2-phase fixed slit portion 54 of the fixed slit plate 50 shown in FIG. 1. The Z1-phase fixed slit portion 53 is a slit pattern including a light-blocking portion 53a made of the base material of the fixed slit plate 50 and a slit-shaped opening 53b formed in the fixed slit plate 50. The Z2-phase fixed slit portion 54 is a slit pattern including a light-blocking portion 54a made of the base material of the fixed slit plate 50 and a slit-shaped opening 54b formed in the fixed slit plate 50. The Z2-phase fixed slit portion 54 is provided adjacent to the Z1-phase fixed slit portion 53 along the radial direction of the rotating disk 30. Also, the Z2-phase fixed slit portion 54 is provided on the inner diameter side of the rotating disk 30 with respect to the Z1-phase fixed slit portion 53. The openings 53b and 54b constitute light-transmitting portions.

[0023] The Z1-phase fixed slit portion 53 represents a 4-bit bit pattern. The opening 53b represents bit value 1, and the light-blocking portion 53a represents bit value 0. In the Z1-phase fixed slit portion 53, the light-blocking portion 53a and the opening 53b are arranged along the clockwise (CW) direction of the rotating disk 30 indicated by arrow A to represent a 4-bit bit pattern in the order of "1011".

[0024] The Z2 phase fixed slit portion 54, like the Z1 phase fixed slit portion 53, represents a 4-bit bit pattern, with the opening 54b representing a bit value of 1 and the light-shielding portion 54a representing a bit value of 0. In the Z1 phase fixed slit portion 53, the light-shielding portion 54a and the opening 54b are arranged along the counterclockwise direction (CCW) of the rotating disk 30 indicated by arrow B, so that the 4-bit bit pattern is represented in the order of "1011". In other words, in the circumferential direction of the rotating disk 30, the Z2 phase fixed slit portion 54 is configured so that the order of the bits in the bit pattern is reversed compared to the Z1 phase fixed slit portion 53.

[0025] Furthermore, since the Z1 phase fixed slit portion 53 and the Z2 phase fixed slit portion 54 are formed symmetrically to each other in the direction along the rotation direction of the rotating disk 30, the Z1 phase fixed slit portion 53 and the Z2 phase fixed slit portion 54 can be easily formed on the fixed slit plate 50.

[0026] In a conventional optical encoder having a Z1 phase and an inverted Z phase, the Z1 phase fixed slit portion and the Z2 phase fixed slit portion of a fixed slit plate are provided adjacent to each other, and the Z1 phase phototransistor and the Z2 phase phototransistor are provided adjacent to each other, and the Z1 phase fixed slit portion and the Z2 phase fixed slit portion are arranged to represent a bit pattern having multiple bits, the bit order of the bit pattern represented by the Z1 phase fixed slit portion and the bit order of the bit pattern represented by the Z2 phase fixed slit portion are configured to be in the same order along the rotation direction of the rotating disk.

[0027] In conventional optical encoders, when light emitted by the Z-phase light-emitting diode (LED) illuminates the light-transmitting portion of the Z1-phase pattern on the rotating disk, the light emitted by the LED illuminates the light-shielding portion of the Z2-phase pattern, which is the inverted Z-phase of the Z1-phase. Therefore, the Z2-phase phototransistor is shielded. However, because the order of the bits in the bit pattern represented by the fixed Z1-phase slit portion and the order of the bits in the bit pattern represented by the fixed Z2-phase slit portion are in the same order along the rotation direction of the rotating disk, crosstalk from the Z1-phase occurs at the opening of the fixed Z2-phase slit portion, resulting in inaccurate detection results for the Z2-phase phototransistor. Similarly, when light emitted by the Z-phase LED illuminates the light-transmitting portion of the Z2-phase pattern on the rotating disk and illuminates the light-shielding portion of the Z1-phase pattern, crosstalk from the Z2-phase occurs at the opening of the fixed Z1-phase slit portion, resulting in inaccurate detection results for the Z1-phase phototransistor. As a result, there was a problem in that the accuracy of origin detection of the rotating disk in optical encoders deteriorated.

[0028] Furthermore, in conventional optical encoders having such Z1 phase pattern sections and Z2 phase pattern sections, a known measure is to reduce the effect of crosstalk between the Z1 phase and Z2 phase and improve the accuracy of detecting the origin of the rotating disk by not arranging the Z1 phase fixed slit section and the Z2 phase fixed slit section adjacent to each other along the radial direction of the rotating disk, but arranging them with a gap between them. However, when the Z1 phase fixed slit section and the Z2 phase fixed slit section are arranged with a gap between them in the radial direction, the Z1 phase pattern section and the Z2 phase pattern section of the rotating disk also need to be arranged with a gap between them in the radial direction. This increases the size of the fixed slit plate and the rotating disk, as well as the space required for the phototransistor, leading to the problem of increasing the overall size of the optical encoder.

[0029] In this embodiment, in the circumferential direction of the rotating disk 30, the Z2 phase fixed slit portion 54 is configured such that the order of the bits in the bit pattern is reversed compared to the Z1 phase fixed slit portion 53. Therefore, the effect of crosstalk on the openings of the Z1 phase fixed slit portion 53 and the Z2 phase fixed slit portion 54 is reduced, and even when the Z1 phase fixed slit portion 53 and the Z2 phase fixed slit portion 54 are arranged adjacent to each other in the radial direction of the rotating disk 30, a decrease in the detection accuracy of the origin of the rotating disk 30 can be prevented.

[0030] Furthermore, in this embodiment, even if the Z1 phase fixed slit portion 53 and the Z2 phase fixed slit portion 54 are arranged adjacent to each other in the radial direction of the rotating disk 30, a decrease in the detection accuracy of the origin of the rotating disk 30 can be prevented. Therefore, the size of the fixed slit plate and the rotating disk, as well as the space required for the phototransistor, can be reduced, and the optical encoder can be miniaturized.

[0031] As described above, the optical encoder according to this embodiment includes a rotating disk 30 rotatably mounted together with the rotating shaft 20, an A-phase and B-phase pattern section 31 provided on the rotating disk 30 for detecting the rotation angle and rotation direction of the rotating disk 30, a Z1-phase pattern section 33 and a Z2-phase pattern section 34 provided on the rotating disk 30 for detecting the origin of the rotating disk 30, an A-phase fixed slit section 51 and a B-phase fixed slit section 52 having a pattern including an opening, provided opposite the A-phase and B-phase pattern section 31, a Z1-phase fixed slit section 53 having a pattern including an opening 53b, and a Z2-phase pattern section 34. The device comprises a Z2-phase fixed slit portion 54 having a pattern including an opening 54b, a light-emitting diode 40 that emits light irradiated onto the A-phase B-phase pattern portion 31, the Z1-phase pattern portion 33, and the Z2-phase pattern portion 34, an A-phase phototransistor 61 and a B-phase phototransistor 62 that transmit light through the A-phase B-phase pattern portion 31 and receive light that has been transmitted through the A-phase fixed slit portion 51 and the B-phase fixed slit portion 52, a Z1-phase phototransistor 63 that transmits light through the Z1-phase pattern portion 33 and receives light that has been transmitted through the Z1-phase fixed slit portion 53, and a Z2-phase phototransistor 64 that transmits light through the Z2-phase pattern portion 34 and receives light that has been transmitted through the Z2-phase fixed slit portion 54. Furthermore, the Z2 phase pattern section 34 has a pattern that is inverted with respect to the Z1 phase pattern section 33, and in the direction along the circumferential direction of the rotating disk 30, the pattern arrangement order of the Z2 phase pattern section 34 is configured in the opposite direction to the pattern arrangement order of the Z1 phase pattern section 33, and in the direction along the circumferential direction of the rotating disk 30, the pattern arrangement order of the Z2 phase fixed slit section 54 is configured in the opposite direction to the pattern arrangement order of the Z1 phase fixed slit section 53. As a result, the effect of crosstalk on the openings of the Z1 phase fixed slit section 53 and the Z2 phase fixed slit section 54 is reduced, and the detection accuracy of the origin of the rotating disk 30 can be improved in an optical encoder having patterns for the Z1 phase fixed slit section 53 and the Z2 phase fixed slit section 54 for origin detection.

[0032] Furthermore, since the Z1 phase fixed slit portion 53 and the Z2 phase fixed slit portion 54 are configured symmetrically with respect to each other in the direction along the circumferential direction of the rotating disk 30, the Z1 phase fixed slit portion 53 and the Z2 phase fixed slit portion 54 can be formed on the fixed slit plate 50 in a simple manner.

[0033] Furthermore, since the A-phase B-phase pattern section 31, the Z1-phase pattern section 33, and the Z2-phase pattern section 34 include transmissive patterns formed on the rotating disk 30, this embodiment can be easily used with known transmissive optical encoders.

[0034] In this embodiment, the optical encoder 1 was a transmissive optical encoder in which an A-phase and B-phase pattern section 31 was provided on a rotating disk 30 made of a transparent material, and an A-phase phototransistor 61, a B-phase phototransistor 62, a Z1-phase phototransistor 63, and a Z2-phase phototransistor 64 were provided on the rotating disk 30 and a fixed slit plate 50 between the A-phase light-emitting diode 41, a B-phase light-emitting diode 42, and a Z-phase light-emitting diode 43. The present invention is not limited thereto, and even when using a known reflective optical encoder, the present invention can be used in a reflective optical encoder by configuring the Z1-phase fixed slit section and the Z2-phase fixed slit section of the fixed slit plate in the same manner as in this embodiment.

[0035] In other words, the Z1-phase fixed slit portion and the Z2-phase fixed slit portion of the fixed slit plate according to this embodiment can be used in a known reflective optical encoder in which the A-phase B-phase pattern portion, the Z1-phase pattern portion and the Z2-phase pattern portion include a reflective pattern formed on the surface of a rotating disk.

[0036] Furthermore, in this embodiment, the surface of the rotating disk 30, which is made of a transparent material, is provided with a light-shielding pattern consisting of an A-phase B-phase pattern portion, a Z1-phase pattern portion 33, and a Z2-phase pattern portion 34. However, the embodiment is not limited to this, and for example, the A-phase B-phase pattern portion, the Z1-phase pattern portion, and the Z2-phase pattern portion may be provided by forming openings in a rotating disk made of an opaque material such as metal.

[0037] Furthermore, the bit patterns shown by the patterns of the Z1 phase pattern section 33, the Z2 phase pattern section 34, the Z1 phase fixed slit section 53, and the Z2 phase fixed slit section 54 in this embodiment are illustrative examples, and bit patterns with bit lengths and bit values ​​other than those shown in this embodiment may be used as appropriate.

[0038] Furthermore, in this embodiment, A-phase light-emitting diodes 41, B-phase light-emitting diodes 42, and Z-phase light-emitting diodes 43 constituting the light-emitting element were provided, but other types of light-emitting elements may be provided instead. In addition, in this embodiment, A-phase phototransistors 61, B-phase phototransistors 62, Z1-phase phototransistors 63, and Z2-phase phototransistors 64 constituting the light-receiving element were provided, but other types of light-receiving elements may be provided instead.

[0039] Furthermore, in this embodiment, the A-phase light-emitting diode 41, the B-phase light-emitting diode 42, and the Z-phase light-emitting diode 43 were provided separately. However, instead of the A-phase light-emitting diode 41 and the B-phase light-emitting diode 42, only one light-emitting diode may be provided, and a Z-phase light-emitting diode may be further provided. Alternatively, instead of the A-phase light-emitting diode 41, the B-phase light-emitting diode 42, and the Z-phase light-emitting diode 43, only one light-emitting diode may be provided.

[0040] Furthermore, in this embodiment, the A-phase phototransistor 61, B-phase phototransistor 62, Z1-phase phototransistor 63, and Z2-phase phototransistor 64 were provided separately. However, instead, a single photodetector may be provided on which the A-phase light-receiving section, B-phase light-receiving section, Z1-phase light-receiving section, or Z2-phase light-receiving section are arbitrarily combined to form a single photodetector.

[0041] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims. [Explanation of Symbols]

[0042] 20 Rotating shaft, 30 Rotating disk, 31 A-phase B-phase pattern section (rotation detection pattern section), 33 Z1-phase pattern section (first origin detection pattern section), 34 Z2-phase pattern section (second origin detection pattern section), 41 A-phase light-emitting diode (light-emitting element), 42 B-phase light-emitting diode (light-emitting element), 43 Z-phase light-emitting diode (light-emitting element), 51 A-phase fixed slit section (rotation detection fixed slit section), 52 B-phase fixed slit section (rotation detection fixed slit section), 53 Z1-phase fixed slit section (first origin detection fixed slit section), 53b Aperture (light-transmitting section), 54 Z2-phase fixed slit section (second origin detection fixed slit section), 54b Aperture (light-transmitting section), 61 A-phase phototransistor (light-receiving element), 62 B-phase phototransistor (light-receiving element), 63 Z1-phase phototransistor (light-receiving element), 64 Z2-phase phototransistor (light-receiving element).

Claims

1. A rotating disk (30) is provided to rotate together with the rotating shaft (20), A rotation detection pattern section (31) for detecting the rotation angle and rotation direction of the rotating disk (30) is provided on the rotating disk (30), The rotating disk (30) is provided with a first origin detection pattern section (33) and a second origin detection pattern section (34) for detecting the origin of the rotating disk (30), Opposite the rotation detection pattern section (31) are rotation detection fixing slit sections (51, 52) having a pattern including a light-transmitting section, A first origin detection fixed slit portion (53) having a pattern including a light-transmitting portion (53b) is provided opposite the first origin detection pattern portion, A second origin detection fixed slit portion (54) is provided opposite the second origin detection pattern portion and has a pattern including a light-transmitting portion (54b), A light-emitting element (40) that emits light to irradiate the rotation detection pattern section (31), the first origin detection pattern section (33), and the second origin detection pattern section (34), Rotation detection light receiving elements (61, 62) that transmit or reflect light through the rotation detection pattern section (31) and receive light transmitted through the rotation detection fixing slit sections (51, 52), A first origin detection light receiving element (63) receives light that passes through or reflects the first origin detection pattern section (33) and passes through the first origin detection fixed slit section (53), A second origin detection light receiving element (64) that receives light transmitted through or reflected by the second origin detection pattern section (34) and transmitted through the second origin detection fixed slit section (54) and Equipped with, The second origin detection pattern section (34) is provided adjacent to the first origin detection pattern section (33) along the radial direction of the rotating disk (30), and has a pattern that is inverted with respect to the first origin detection pattern section (33). In the direction along the circumferential direction of the rotating disk (30), the arrangement order of the patterns in the second origin detection pattern section (34) is configured in the opposite direction to the arrangement order of the patterns in the first origin detection pattern section (33). The second origin detection fixing slit portion (54) is provided adjacent to the first origin detection fixing slit portion (53) along the radial direction of the rotating disk (30), In the direction along the circumferential direction of the rotating disk (30), the arrangement order of the patterns in the second origin detection fixed slit portion (54) is configured in the opposite direction to the arrangement order of the patterns in the first origin detection fixed slit portion (53). Optical encoder.

2. The optical encoder according to claim 1, wherein the first origin detection fixed slit portion (53) and the second origin detection fixed slit portion (54) are configured symmetrically with respect to each other in a direction along the circumferential direction of the rotating disk (30).

3. The optical encoder according to claim 1 or 2, wherein the rotation detection pattern section (31), the first origin detection pattern section (33), and the second origin detection pattern section (34) are formed on the rotating disk (30) and include a light-transmitting pattern.

4. The optical encoder according to claim 1 or 2, wherein the rotation detection pattern section (31), the first origin detection pattern section (33), and the second origin detection pattern section (34) include a reflection pattern formed on the surface of the rotating disk (30).

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