Photoelectric encoder

• US 20050006572A1
• Filed: 05/12/2004
• Published: 01/13/2005
• Est. Priority Date: 05/13/2003
• Status: Active Grant

• Current Assignee: Mitutoyo Corporation
• Original Assignee: Mitutoyo Corporation
• Inventors: Kojima, Kenji
• Granted Patent: US 6,906,311 B2
• Time in Patent Office: Days
• US Class Current: 250/231.130
• CPC Class Codes: G01D 5/34707 Scales; Discs, e.g. fixation, fabrication, compensation
• CPC Class Codes: G01D 5/34715 Scale reading or illumination devices
• CPC Class Codes: G01D 5/38 by diffraction gratings

Abstract

A photoelectric encoder includes an optical receipt chip on which the light acceptance surfaces of a plurality of photodiodes are disposed two-dimensionally. Four optical signals different in phase from one another (i.e., light signals with phase “A,” phase “B,” phase “AA,” and phase “BB”) are guided to fall onto the light acceptance surfaces. The shape of each light acceptance surface is a regular hexagon.

Claims

1. A photoelectric encoder comprising:

a light source;

a scale including a first optical grating for receiving irradiation of light from said light source; and

a light-receiving unit including light-receiving elements each having a hexagonal light acceptance surface for permitting incidence of an optical signal as generated based on the light falling onto said first optical grating, said light-receiving unit being relatively movably disposed with a gap provided between itself and said scale for detecting a plurality of phase-different optical signals by said light-receiving elements as two-dimensionally disposed on a plane opposing said first optical grating.

2. The photoelectric encoder according to claim 1, wherein said light-receiving elements are such that neighboring ones are different from each other in phase of optical signals to be detected.

3. The photoelectric encoder according to claim 1, wherein said light-receiving elements are an optical receipt chip including second optical gratings, each of these having light shield portions disposed above each of said light acceptance surfaces.

4. The photoelectric encoder according to claim 3, wherein said optical receipt chip includes:

contact portions underlying said light shield portions with electrical conductivity and being connected thereto while being in contact with said light acceptance surfaces; and

electrical wiring lines of said light-receiving elements as connected to said light shield portions.