# US 2019/0377073 A1 · Distance-measuring apparatus with polarizing filter

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- Number: US 2019/0377073 A1
- Document ID: US20190377073A1
- Status: Published application
- Kind: A1
- Application number: 16/384,934
- Filed: 2019-04-16
- Published: 2019-12-12
- Earliest claimed: 2018-06-08
- Assignees: Fanuc Corporation
- Applicants: Fanuc Corporation
- Inventors: Yuuki TAKAHASHI; Atsushi WATANABE; Minoru NAKAMURA
- Web page: https://patentgrep.com/patent/US20190377073A1

## CPC

- G01B 11/026: {by measuring distance between sensor and object (G01B11/0608 takes precedence)}
- G01S 7/499: using polarisation effects
- G01B 11/14: for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00)
- G01S 7/4816: {of receivers alone}
- G01S 7/4918: {Controlling received signal intensity, gain or exposure of sensor}
- G01S 17/04: Systems determining the presence of a target
- G01S 17/08: for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48)
- G01S 17/36: with phase comparison between the received signal and the contemporaneously transmitted signal
- G01V 8/14: using reflectors
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)

## Abstract

A distance-measuring apparatus includes an optical window incorporating a first polarizing filter that polarizes reference light and a second polarizing filter that polarizes incident light in a direction inclined at 90 degrees relative to a polarization direction of the first polarizing filter.

## Claims

### Claim 1

A distance-measuring apparatus comprising:
a light emission section that emits reference light intensity-modulated at a predefined frequency;
a light reception section that receives incident light from a target space to be measured;
a distance calculation section that calculates a distance to an object in the target space to be measured, based on a phase difference between the reference light and the incident light; and
an optical window incorporating a first polarizing filter that polarizes the reference light and a second polarizing filter that polarizes the incident light in a direction inclined at 90 degrees relative to a polarization direction of the first polarizing filter.

### Claim 2 (depends on 1)

The distance-measuring apparatus according to claim 1, further comprising a lens between the second polarizing filter and the light reception section.

### Claim 3 (depends on 1)

The distance-measuring apparatus according to claim 1, wherein the optical window is detachable.

### Claim 4 (depends on 1)

The distance-measuring apparatus according to claim 1, further comprising a reference reflector and a deterioration determination section that determines deterioration of the first polarizing filter and the second polarizing filter, based on an intensity of reflection from the reference reflector.

### Claim 5 (depends on 4)

The distance-measuring apparatus according to claim 4, wherein the reference reflector comprises a retroreflection portion.

### Claim 6 (depends on 5)

The distance-measuring apparatus according to claim 5, wherein the reference reflector further comprises a diffuse reflection portion.

### Claim 7 (depends on 6)

The distance-measuring apparatus according to claim 6, wherein the deterioration determination section determines the deterioration, based on an intensity of reflection from the retroreflection portion and an intensity of reflection from the diffuse reflection portion.

### Claim 8 (depends on 4)

The distance-measuring apparatus according to claim 4, further comprising a reference reflector registration section that registers in advance a reference position of the reference reflector on an image and an intensity of reflection from the reference position.

### Claim 9 (depends on 7)

The distance-measuring apparatus according to claim 7, wherein the deterioration determination section searches an image for a shape of the reference reflector and identifies the retroreflection portion and the diffuse reflection portion, based on a position and posture of the shape.

### Claim 10 (depends on 4)

The distance-measuring apparatus according to claim 4, further comprising a reference reflector registration section that registers the shape of the reference reflector.

### Claim 11 (depends on 9)

The distance-measuring apparatus according to claim 9, wherein the shape of the reference reflector is a predefined shape.

### Claim 12 (depends on 8)

The distance-measuring apparatus according to claim 8, wherein the reference position comprises a position at which a specular reflection has occurred and a position at which no specular reflection has occurred.