Optical scale having wires, method for manufacturing optical scale having wires,and optical encode

Patent metadata

Field	Value
Publication number	US-9410858-B2
Application number	US-201214355149-A
Country	US
Kind code	B2
Filing date	Oct 31, 2012
Priority date	Oct 31, 2011
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

An optical scale, a method for manufacturing an optical scale, and an optical encoder. The optical scale includes a plurality of wires provided thereon so that the wires do not intersect each other and each of the tangential directions of the respective wires changes continuously. The optical encoder includes the optical scale, a light source, an optical sensor, and a computing unit. The optical sensor includes a first polarizing layer that splits incident light that is light source light from the light source passed through or reflected on the optical scale and being incident on the first polarizing layer to a first polarization direction, a second polarizing layer that splits the incident light to a second polarization direction, a first photoreceiver that receives first polarized light split by the first polarizing layer, and a second photoreceiver that receives second polarized light split by the second polarizing layer.

First claim

The invention claimed is:

1. An optical scale through or on which light source light from a light source is passed or reflected, the optical scale comprising:
a plurality of wires arranged thereon so that the wires do not intersect each other and each of tangential directions of the wires, having tangent angles with respect to radius directions of the wires, changes continuously, wherein
the tangential directions are oriented same in areas in which intervals between adjacent wires are same, and the tangential directions are oriented differently in areas in which the intervals between adjacent wires are different, and
a change in each of the tangential directions per rotation of the optical scale is cyclic and the number of cycles of the change is plural.

2. The optical scale according to claim 1 , further comprising a protection layer or a substrate covering the wires.

3. The optical scale according to claim 1 , wherein the wires are provided in a plurality of layers in a thickness direction in which transmissive light or reflected light is incident.

4. An optical encoder comprising:
an optical scale on which a plurality of wires are arranged so that the wires do not intersect each other and each of tangential directions of the wires, having tangent angles with respect to radius directions of the wires, changes continuously;
a light source;
an optical sensor including a first polarizing layer that splits incident light that is light source light from the light source passed through or reflected on the optical scale and being incident on the first polarizing layer into a first polarized light polarized in a first polarization direction, a second polarizing layer that splits the incident light into a second polarized light polarized in a second polarization direction, a first photoreceiver that receives the first polarized light, and a second photoreceiver that receives the second polarized light; and
a computing unit that computes a relative amount of movement of the optical scale with respect to the optical sensor, from light intensities of the first polarized light and of the second polarized light, wherein
the tangential directions are oriented same in areas in which intervals between adjacent wires are same, and the tangential directions are oriented differently in areas in which the intervals between adjacent wires are different, and
a change in each of the tangential directions per rotation of the optical scale is cyclic and the number of cycles of the chance is plural.

5. The optical encoder according to claim 4 , wherein the optical sensor uses a part of the wires whose tangential directions are oriented same as a sensing area, and receives incident light that is the light source light passed through or reflected on the sensing area and being incident on the optical sensor.

6. The optical encoder according to claim 4 , wherein the optical scale is provided with a first grid pattern having a first cycle at which each of the tangential directions changes cyclically and a second grid pattern having a second cycle at which each of the tangential directions changes cyclically so that number of cycles per rotation is different from that of the first cycle.

7. The optical encoder according to claim 4 , wherein the first photoreceiver and the second photoreceiver on the optical sensor are positioned alternatingly and spaced uniformly.

8. The optical encoder according to claim 4 , further comprising a protection layer or a substrate covering the wires.

9. The optical encoder according to claim 4 , wherein the wires are provided in a plurality of layers in a thickness direction in which transmissive light or reflected light is incident.

10. The optical encoder according to claim 6 , wherein the number of first cycles per rotation and the number of second cycles per rotation are mutually prime.

11. A method for manufacturing an optical scale comprising:
preparing a substrate, and forming a pattern of recesses and protrusions on a resist layer of the substrate; and
forming metal in a manner following the pattern of the recesses and protrusions, wherein
the metal is provided on a surface of the substrate as a plurality of wires so that the wires do not intersect each other and each of tangential directions of the wires, having tangent angles with respect to radius directions of the wires, changes continuously,
the tangential directions are oriented same in areas in which intervals between adjacent wires are same, and the tangential directions are oriented differently in areas in which the intervals between adjacent wires are different, and
a change in each of the tangential directions per rotation of the optical scale is cyclic and the number of cycles of the change is plural.

12. The method for manufacturing an optical scale according to claim 11 , wherein at the forming a pattern of recesses and protrusions on a resist layer of the substrate, a mold is pressed against the resist layer so that recesses and protrusions on the mold are transferred onto the resist layer.

13. The method for manufacturing an optical scale according to claim 11 , wherein at the forming metal in a manner following the pattern of the recesses and protrusions, the wires are formed by plating or vapor deposition.

Assignees

• Oguchi Toshiaki
• Sasao Kunihiko
• Sugita Sumio
• Nsk Ltd

Inventors

• Oguchi Toshiaki
• Sasao Kunihiko
• Sugita Sumio

Classifications

• G01L3/08

  involving optical means for indicating · CPC title

• B62D5/0481

  monitoring the steering system, e.g. failures · CPC title

• G01D5/34715

  Scale reading or illumination devices · CPC title

• G01D5/345

  Polarising encoders · CPC title

• G01L3/12 Primary

  involving photoelectric means · CPC title