# US 5,704,130 A · Measuring instrument

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- Number: US 5,704,130 A
- Document ID: US5704130A
- Status: Granted
- Kind: A
- Application number: 08/783,787
- Filed: 1997-01-15
- Granted: 1998-01-06
- Earliest claimed: 1992-01-22
- Assignees: Raytec Limited
- Inventors: Victor Augustin; Eduard Fischer
- Web page: https://patentgrep.com/patent/US5704130A

## CPC

- G01C 9/06: Electric or photoelectric indication or reading means
- G01C 2009/066: {optical}
- 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)

## Abstract

An optical measuring system to indicate or determine the relative position of an object and/or a substrate in relation to a horizontal plane comprises an at least partially transparent measuring chamber containing two non-miscible media with different densities, one of the media being at least partially transparent or translucent and at least the other being a fluid medium. The relative position is found on the basis of the position of the at least partially transparent or translucent medium in the measuring chamber, when what is concerned is an optical instrument operating on the principle of a spirit level. On one side of the measuring chamber is a light source and on the opposite side there is an optical measuring cell or a flat, light-sensitive sensor. The light transmitted from the light source through the at least partially transparent or translucent medium is projected on the optical measuring cell or the flat, light-sensitive sensor and the projection is used to determine the relative position of the object in relation to the horizontal.

## Claims

### Claim 1

A measuring instrument for determining the relative position of an object with respect to a horizontal plane, comprising:
a measuring chamber embodied as a hollow body, said measuring chamber containing two media of different density which cannot be mixed, one of the media being at least partially transparent and the other of the media being a fluid media;
a light source for emitting light which is transmitted through said at least partially transparent medium; and
a light-sensitive sensor onto which the light transmitted through said at least partially transparent medium is projected for forming a projection entirely placed on said light-sensitive sensor, wherein:
said measuring chamber, said light source and said light-sensitive sensor are arranged in axial alignment along a horizontal axis, with said light source being disposed on one side of said measuring chamber and with said light-sensitive sensor being disposed on the other side of said measuring member,
said arrangement being such that said projection is an amplification of said at least partially transparent medium, and
the relative position of an object with respect to a horizontal plane being determined on the basis of said at least partially transparent medium in said measuring chamber.

### Claim 2 (depends on 1)

The measuring instrument as defined in claim 1, wherein said hollow body comprises a circular tube.

### Claim 3 (depends on 1)

The measuring instrument as defined in claim 1, wherein said hollow body comprises a circular disk.

### Claim 4 (depends on 1)

The measuring instrument as defined in claim 1, wherein one of said media polarizes light.

### Claim 5 (depends on 1)

The measuring instrument as defined in claim 1, wherein both media are fluid media, with one being opaque or impervious to light, and wherein both media are enclosed in said hollow body.

### Claim 6 (depends on 5)

The measuring instrument as defined in claim 5, wherein said hollow body is made of glass.

### Claim 7 (depends on 5)

The measuring instrument as defined in claim 5, wherein said at least partially transparent medium is less than said opaque medium.

### Claim 8 (depends on 1)

The measuring instrument as defined in claim 1, wherein said hollow body defines a zenith, and wherein said partially transparent medium is disposed at said zenith.

### Claim 9 (depends on 1)

The measuring instrument as defined in claim 1, wherein said hollow body defines a zenith, and wherein said partially transparent medium is disposed at the side opposite to said zenith.

### Claim 10 (depends on 1)

The measuring instrument as defined in claim 1, wherein said hollow body has a constant cross section.

### Claim 11 (depends on 1)

The measuring instrument as defined in claim 1, wherein said light-sensitive sensor compresses a position-sensitive detector.

### Claim 12 (depends on 1)

The measuring instrument as defined in claim 1, wherein said light-sensitive sensor comprises a matrix-like detector.