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Browse Prior Art Database

Method of Producing a Divergent Sheet of Light

IP.com Disclosure Number: IPCOM000062796D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Goodman, DS: AUTHOR [+2]

Abstract

This paper describes the production of narrow sheet of light with variable angular subtense and direction by reflecting a narrow sheet of light with fixed angular subtense and direction from either a reflective cylinder at variable radial position or from a reflective cone at variable radial and axial positions. Such sheets of light for robotic vision have previously been produced by expensive scanners having moving parts, or with cylindrical lenses. With cylindrical lenses, the range of divergence angles has practical limits, and lens transmittance considerably varies with angle.

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Method of Producing a Divergent Sheet of Light

This paper describes the production of narrow sheet of light with variable angular subtense and direction by reflecting a narrow sheet of light with fixed angular subtense and direction from either a reflective cylinder at variable radial position or from a reflective cone at variable radial and axial positions. Such sheets of light for robotic vision have previously been produced by expensive scanners having moving parts, or with cylindrical lenses. With cylindrical lenses, the range of divergence angles has practical limits, and lens transmittance considerably varies with angle.

The manner of producing a narrow beam of light with variable angular subtense and direction using a reflective cylinder is seen in Fig. 1. An incident collimated beam of light 10 is directed at a smooth reflective cylinder 15, with the axis of cylinder 15 being kept normal to the direction of the beam of light 10. The resulting beam or sheet of light 20 may be described in terms of its width, divergence, and direction. The width of the resulting light beam 20 in the direction parallel to the axis of the cylinder 15 typically is identical to the width of the incident beam 10 except for changes due to diffraction.

The divergence and direction of the resulting sheet 20 are determined by the ratio of the height of the incoming beam in the direction perpendicular to the axis of the cylinder to the radius of the cylinder, and the location at which the incident beam 10 intersects the reflecting cylinder 15. An incident beam with a given height will therefore produce resulting beams of different divergence depending upon the location of the intersection of the beam with the cylinder. Likewise, the "direction", which may be defined by vectors representing the outermost beams of reflected light sheet 20, will change depending on the intersection location. Thus, with a relative radial movement of the...