# US 2010/0166433 A1 · Optical signal transfer device

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- Number: US 2010/0166433 A1
- Document ID: US20100166433A1
- Status: Published application
- Kind: A1
- Application number: 12/654,436
- Filed: 2009-12-18
- Published: 2010-07-01
- Earliest claimed: 2008-12-25
- Assignees: Topcon Corporation
- Inventors: Masanori Fujimoto; Kunihiro Hayashi
- Web page: https://patentgrep.com/patent/US20100166433A1

## CPC

- G01C 15/002: {Active optical surveying means (optical plumbing G01C15/105)}
- G02B 6/3604: {Rotary joints allowing relative rotational movement between opposing fibre or fibre bundle ends}
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An optical signal transfer device includes a transmitter system and a receiver system for signal transfer between a base unit and a rotary unit. The receiver system includes a natural number n of light receiving portions forming a ring-like light receiving area around the rotary axis and a light reception controller. The transmitter system includes a light emitting portion, an emission controller, and an optical guide which guides a light beam from the light emitting portion to a light emitting area facing the light receiving area. The optical guide guides a light beam to the light emitting area in one of n equally divided areas of a ring-like opposing area which opposes the light receiving area. Therefore, one of the n light receiving portions always face the light emitting area irrespective of rotary position of the receiver system around the rotary axis relative to the transmitter system.

## Claims

### Claim 1

An optical signal transfer device which transfers a signal between a base unit and a rotary unit rotatable around a rotary axis and supported on the base unit, the device comprising:
a transmitter system provided in one of the base unit and the rotary unit to transmit a signal; and
a receiver system provided in the other of the base unit and the rotary unit to receive the signal from the transmitter system, wherein:
the receiver system comprises n light receiving portions which are rotated around the rotary axis relative to the transmitter system on a single plane orthogonal to the rotary axis by a relative rotation of the base unit and the rotary unit and form a single ring-like light receiving area, and a light reception controller which processes an electric signal output from each of the light receiving portions, the n being a natural number;
the transmitter system comprises a light emitting portion, an emission controller which drives the light emitting portion in accordance with a transmit signal, and an optical guide which guides a light beam from the light emitting portion to a light emitting area provided in an area opposing the light receiving area;
the opposing area is an area in a ring-like form around the rotary axis opposing the light receiving area and is equally divided into n areas in a circumferential direction; and
the optical guide guides the light beam to at least one of the n divided areas as the light emitting area, so that at least one of the n light receiving portions is to face the light emitting area irrespective of a rotary position of each of the light receiving portions relative to the transmitter system.

### Claim 2 (depends on 1)

An optical signal transfer device according to claim 1, wherein:
the optical guide includes an exit face which opposes the light receiving area and emits the light beam, and includes inside a scattering face which scatters the light beam in a direction to the exit face.

### Claim 3 (depends on 2)

An optical signal transfer device according to claim 2, wherein the scattering face is formed on a face opposing the exit face.

### Claim 4 (depends on 3)

An optical signal transfer device according to claim 3, wherein
the exit face is formed to be such a lens face as to increase an amount of a light beam, among the light beam the exit face emits, to be incident on the light receiving portions of the receiver system.