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Optical Range Finder

IP.com Disclosure Number: IPCOM000094943D
Original Publication Date: 1965-Jul-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Rabedeau, ME: AUTHOR

Abstract

This automatic range finder utilizing the light ray triangulation principle determines the distance to an object. There is a blue light source 11 having lamp 11a and blue filter 11b. There is also a green light source 12 having lamp 12a and green filter 12b. Lenses 11c and 12c are associated with their respective light sources and are movable by cams 11d and 12d to aim the light sources. Thus, the light rays converge at selected points along central axis 13. Axis 13 has disposed on it a lens 14c. The latter is driven by a cam 14d to adjust the lens focus at various points along 13. Dichroic mirror 16 is disposed behind lens 14c to split the reflected blue and green images passing through lens 14c. Phototubes 17 and 18 are mounted adjacent mirror 16 for detecting the intensities of the blue and green images, respectively.

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Optical Range Finder

This automatic range finder utilizing the light ray triangulation principle determines the distance to an object. There is a blue light source 11 having lamp 11a and blue filter 11b. There is also a green light source 12 having lamp 12a and green filter 12b.

Lenses 11c and 12c are associated with their respective light sources and are movable by cams 11d and 12d to aim the light sources. Thus, the light rays converge at selected points along central axis
13. Axis 13 has disposed on it a lens 14c. The latter is driven by a cam 14d to adjust the lens focus at various points along 13.

Dichroic mirror 16 is disposed behind lens 14c to split the reflected blue and green images passing through lens 14c. Phototubes 17 and 18 are mounted adjacent mirror 16 for detecting the intensities of the blue and green images, respectively.

In operation, the range finder is placed so that axis 13 intersects the surface of object 19 whose range is to be determined. The angle of convergence between the blue and the green light rays is then varied by cams 11d and 12d until the blue and green images coincide at the surface of the object. This coincidence is detected by a large signal output from either one or both photocells 17 and 18. When the latter produce such large signal output, the angle of convergence between the blue and the green light rays is measured and the range of the object is computed by triangulation.

To prevent interference from ambient light, lig...