US 4,068,121 AGranted

Light collector and prism light source for photoelectric readers

AssigneeTally Corporation

InventorsEdward D. Bringhurst, John L. Marshall

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Abstract

A light collector and prism that collects light from a single bulb and produces a narrow strip light beam is disclosed. The light collector and prism is formed of an elongate, integral piece of transparent material (plastic) and includes a light collecting section at one end and a prism section at the other end. Light rays emitted from a small bulb positioned in an aperture in the light collecting section are collected, to some extent (e.g., imperfectly) collimated, and directed into the prism section. The prism section extends outwardly from the collector section so as to receive the light rays collected, collimated and directed by the collecting section. The prism section includes a plurality of prism surfaces located along one edge thereof. Light rays directed by the light collecting section toward the prism section are reflected by the prism surfaces toward an opposing, narrow, light emitting edge of the prism section. Light rays emitted from the narrow edge form a narrow strip light beam. Preferably, all of the surfaces of the light collector and prism are metalized, except for the aperture within which the light source is mounted and, the narrow edge of the prism through which the narrow strip light beam is emitted.

Claims32

Dependent claims

In a photoelectric reader including a light source, mounted such that light rays are directed toward a region whereat an apertured information medium is positioned or passes, and light sensors, located on the side of the apertured information medium remote from the light receiving side, for receiving light passing through the apertures in the apertured information medium, the improvement comprising a light source for producing a continuous, narrow strip light beam, said light source including:

A. an elongate, integral light collector and prism having a central longitudinal axis, comprising:
1. a cone shaped collector section formed at one end of said light collector and prism, said collector section including an aperture located along said central longitudinal axis suitable for receiving a point source light emitting element, the internal surfaces of said aperture and the external surfaces of said light collector section being formed so as to collect light rays emitted by a point source light emitting element positioned in said aperture, imperfectly collimate said light rays and direct said imperfectly collimated light rays in a predetermined direction generally, but not entirely, parallel to said central longitudinal axis of said light collector and prism;
and,
2. a prism section formed at the other end of said elongate, integral light collector and prism, said prism section being positioned along said central longitudinal axis so as to receive said imperfectly collimated light rays directed in a direction generally, but not entirely, parallel to said central longitudinal axis of said light collector and prism by said collector section, said prism section being elongated and including opposed stepped and narrow edges, said stepped edge including tread regions lying parallel to said central longitudinal axis and riser regions lying transverse to said central longitudinal axis, said riser regions positioned so as to receive light rays directed in a direction parallel to said central axis by said collector section and redirect said light rays outwardly through said narrow edge, said tread regions positioned so as to receive light rays directed in a direction not entirely parallel to said central longitudinal axis by said collector section and redirect said light rays outwardly through said narrow edge;
and,
B. a point source light emitting element mounted in said aperture in said collector section of said elongate, integral light collector and prism.

3 more elements

A light collector and prism comprising:

1. a cone shaped collector section including an aperture located along a central longitudinal axis suitable for receiving a point source light emitting element, the internal surfaces of said aperture and the external surfaces of said light collector section being formed so as to collect light rays emitted by a point source light emitting element positioned in said aperture, imperfectly collimate said light rays and direct said imperfectly collimated light rays in a predetermined direction generally, but not entirely, parallel to said central longitudinal axis;
and,
2. a prism section integrally formed at the end of said collector section remote from said aperture, said prism section being positioned along said central longitudinal axis so as to receive said imperfectly collimated light rays directed in a direction generally, but not entirely, parallel to said central longitudinal axis by said collection section, said prism section being elongated and including opposed stepped and narrow edges, said stepped edge including tread regions lying parallel to said central longitudinal axis and riser regions lying transverse to said central longitudinal axis, said riser regions positioned so as to receive light rays directed in a direction parallel to said central longitudinal axis by said collector section and redirect said light rays outwardly through said narrow edge, said tread regions positioned so as to receive light rays directed in a direction not entirely parallel to said central longitudinal axis by said collector section and redirect said light rays outwardly through said narrow edge, said outwardly redirected light rays forming a continuous narrow strip light beam.

Dependencies are inferred from the claim text.