Encoder, motor with encoder, and servo system having a plurality of light receiving array to receive light reflected by slit tracks comprising incremental patterns and absolute pattern

Patent metadata

Field	Value
Publication number	US-9562794-B2
Application number	US-201414532006-A
Country	US
Kind code	B2
Filing date	Nov 4, 2014
Priority date	Nov 5, 2013
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

An encoder includes a plurality of slit tracks, a point light source, a first light-receiving array, a second light-receiving array, and a third light-receiving array. The plurality of slit tracks respectively comprises a plurality of reflection slits arranged along a measurement direction. The point light source is configured to emit diffusion light to the plurality of slit tracks. The first light-receiving array is configured to receive light reflected by the slit track comprising an incremental pattern. The second light-receiving array is configured to receive light reflected by the slit track comprising an incremental pattern longer in pitch than other incremental patterns. The third light-receiving array is configured to receive light reflected by the slit track comprising an absolute pattern.

First claim

What is claimed is:

1. An encoder, comprising:
a plurality of slit tracks that respectively comprise a plurality of reflection slits arranged along a measurement direction;
a point light source configured to emit diffusion light to the plurality of slit tracks;
a first light-receiving array configured to receive light reflected by the slit track comprising an incremental pattern;
a second light-receiving array configured to receive light reflected by the slit track comprising an incremental pattern longer in pitch than other incremental patterns; and
a third light-receiving array configured to receive light reflected by the slit track comprising an absolute pattern, and
wherein the first light-receiving array and the second light-receiving array are disposed at positions further on a direction side where the point light source is disposed rather than where the third-light receiving array is disposed.

2. The encoder according to claim 1 , wherein:
the point light source is disposed between the arrays consisting of the first light-receiving array and the second light-receiving array, and the third light-receiving array.

3. The encoder according to claim 1 , wherein:
the measurement direction is a circumferential direction with a center axis as the center; and
the point light source and the first to third light-receiving arrays are disposed in the order of the first light-receiving array, the second light-receiving array, the point light source, and the third light-receiving array, toward the center axis from an outer portion in a radial direction of a circle.

4. The encoder according to claim 2 , wherein:
the measurement direction is a circumferential direction with a center axis as the center; and
the point light source and the first to third light-receiving arrays are disposed in the order of the first light-receiving array, the second light-receiving array, the point light source, and the third light-receiving array, toward the center axis from an outer portion in a radial direction of a circle.

5. The encoder according to claim 1 , wherein:
the measurement direction is a circumferential direction with a center axis as the center; and
the point light source and the first to third light-receiving arrays are disposed in the order of the third light-receiving array, the point light source, the first light-receiving array, and the second light-receiving array, toward the center axis from an outer portion in a radial direction of a circle.

6. The encoder according to claim 2 , wherein:
the measurement direction is a circumferential direction with a center axis as the center; and
the point light source and the first to third light-receiving arrays are disposed in the order of the third light-receiving array, the point light source, the first light-receiving array, and the second light-receiving array, toward the center axis from an outer portion in a radial direction of a circle.

7. The encoder according to claim 1 , wherein:
the point light source is disposed between the first light-receiving array and the second light-receiving array.

8. The encoder according to claim 7 , wherein:
the measurement direction is a circumferential direction with a center axis as the center; and
the point light source and the first to third light-receiving arrays are disposed in the order of the first light-receiving array, the point light source, the second light-receiving array, and the third light-receiving array, toward the center axis from an outer portion in a radial direction of a circle.

9. The encoder according to claim 7 , wherein:
the measurement direction is a circumferential direction with a center axis as the center; and
the point light source and the first to third light-receiving arrays are disposed in the order of the third light-receiving array, the first light-receiving array, the point light source, and the second light-receiving array, toward the center axis from an outer portion in a radial direction of a circle.

10. The encoder according to claim 1 , wherein:
the third light-receiving array is configured as a light-receiving array of two tracks disposed so as to be practically symmetrical, sandwiching the point light source.

11. The encoder according to claim 1 , wherein:
the point light source, the first light-receiving array, the second light-receiving array, and the third light-receiving array are disposed on one substrate.

12. An encoder, comprising:
a plurality of slit tracks that respectively comprise a plurality of reflection slits arranged along a measurement direction;
a point light source configured to emit diffusion light to the plurality of slit tracks;
a first light-receiving array configured to receive light reflected by the slit track comprising an incremental pattern;
a second light-receiving array configured to receive light reflected by the slit track comprising an incremental pattern longer in pitch than other incremental patterns;
a third light-receiving array configured to receive light reflected by the slit track comprising an absolute pattern; and
one substrate where the point light source, the first light-receiving array, and the second light-receiving array are disposed, and
wherein the first light-receiving array and the second light-receiving array are disposed at positions further on a direction side where the point light source is disposed rather than where the third-light receiving array is disposed on the substrate.

13. An encoder, comprising:
a plurality of slit tracks that respectively comprise a plurality of reflection slits arranged along a measurement direction;
means for emitting diffusion light to the plurality of slit tracks;
first means for receiving light reflected by the slit track comprising an incremental pattern;
second means for receiving light reflected by the slit track comprising an incremental pattern longer in pitch than other incremental patterns; and
third means for receiving light reflected by the slit track comprising an absolute pattern, and
wherein the first means and the second means are disposed at positions further on a direction side where the means for emitting diffusion light is disposed rather than where the third means is disposed.

14. A motor with an encoder, comprising:
a linear motor wherein a mover moves with respect to a stator, or a rotary motor wherein a rotor rotates with respect to a stator; and
the encoder according to claim 1 configured to detect at least one of a position and a velocity of the mover or the rotor.

15. A motor with an encoder, comprising:
a linear motor wherein a mover moves with respect to a stator, or a rotary motor wherein a rotor rotates with respect to a stator; and
the encoder according to claim 12 configured to detect at least one of a position and a velocity of the mover or the rotor.

16. A servo system comprising:
a linear motor wherein a mover moves with respect to a stator, or a rotary motor wherein a rotor rotates with respect to a stator;
the encoder according to claim 1 configured to detect at least one of a position and a velocity of the mover or the rotor; and
a controller configured to control the linear motor or the rotary motor based on a detection result of the encoder.

17. A servo system comprising:
a linear motor wherein a mover moves with respect to a stator, or a rotary motor wherein a rotor rotates with respect to a stator;
the encoder according to claim 12 configured to detect at least one of a position and a velocity of the mover or the rotor; and
a controller configured to control the

Assignees

• Yaskawa Electric Corp

Inventors

• Yoshida Yasushi
• Matsutani Yasuhiro
• Yoshidomi Shiro
• Takada Hiroshi
• Arinaga Yuji
• Murokita Ikuma
• Harada Masanobu
• Kondo Hiroki

Classifications

• G01D5/34738

  Axles; Driving or coupling means · CPC title

• G01D5/34776 Primary

  Absolute encoders with analogue or digital scales · CPC title

• G01D5/3473

  Circular or rotary encoders · CPC title