Importance

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Abstract

There is disclosed an apparatus for illuminating a sensing region having an object therein, comprising a reflector that is elongated in a first plane, the reflector having a width dimension that is less than a width dimension of a sensing region to be illuminated, and further having a first curved profile in the first plane about a center of curvature. In a preferred embodiment the reflector is disposed between the center of curvature and the sensing region. In a second plane which is orthogonal to the first plane and includes the center of curvature, a reflecting surface of the reflector has a second curved profile. A plurality of substantially Lambertian light sources each face the reflector for directing light thereto generally in a direction of the center of curvature for reflection toward the sensing region. The second profile preferably comprises a portion of an ellipse and a light source is disposed substantially at a primary focus thereof. The second profile preferably has a gap for transmitting retroreflected light generated within the sensing region therethrough. An upper portion of the second profile comprises a portion of a first surface of revolution selected from the group of ellipse and parabola, and the lower portion of the second profile can comprise a portion of a second surface of revolution selected from the group of ellipse and parabola, a light source being disposed at a focus of each of the first surface of revolution and the second surface of revolution. The assembly is combined in a scanner for reading optical patterns.

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First Claim