Illumination system including a curved mirror for an imaging-based bar code reader
AssigneeSymbol Technologies, Inc.
InventorIgor Vinogradov
Life of this patent
Estimating the term…
Abstract
A method and apparatus for illuminating a target object such as a bar code having areas of differing light reflectivity on the target. A bar code reader has a light source that is selectively activated and a reflecting mirror for reflecting light from the source from a housing to a target object within a field of view of an imaging capturing device. One suitable mirror is a parabolic mirror having a focal point approximately at the location of the light source.
Claims26
A bar code scanner comprising:
- a scanner housing having a housing interior;
- image capturing system within said housing interior for capturing a bar code image;
- and
- an illumination assembly for emitting illumination light from the housing interior to a bar code target object spaced from the housing comprising:
- i) an illumination source energizable to emit light to pass through a region of the scanner housing;
- ii) a light transmitting window and
- ii) a parabolic mirror having a concave surface which extends across a width of said light transmitting window positioned within the housing to reflect light from the illumination source through the light transmitting window to a region of interest outside the scanner housing;
- wherein said illumination source is located at or near a focal point of the parabolic mirror to collimate light reflecting from the mirror.
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A method of scanning a bar code at a region of interest comprising:
- mounting an image analysis circuitry within a scanner housing for capturing a bar code image;
- positioning a parabolic mirror having a concave surface that approximates a parabola within the scanner housing to reflect light from one or more light emitting diodes also positioned within the housing to a region of interest outside the scanner housing;
- wherein the one or more light emitting diodes are positioned within the scanner housing at or near a focal point of the concave surface that approximates a parabola to control collimation of light reflected by the parabolic mirror into the region of interest;
- and
- selectively activating the one or more light emitting diodes to emit light to pass through a region of the scanner housing, bounce off the parabolic mirror, and illuminate the region of interest with controlled collimation outside the scanner housing.
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The method 12 wherein the illumination source is displaced slightly from said focal point of the parabolic mirror to control the collimation of light reflecting from the mirror.
A bar code scanner comprising:
- a scanner housing having a housing interior;
- image analysis means within said housing interior for capturing a bar code image;
- and
- illumination means for emitting illumination light from the housing interior to a bar code target object spaced from the housing comprising:
- i) source means comprising one or more light emitting diodes for emitting light to pass through a region of the scanner housing;
- and
- ii) reflection means comprising a parabolic mirror positioned within the housing for intercepting and reflecting light from the source means to a region of interest outside the scanner housing;
- said light emitting diodes located at or near a focal point of the parabolic mirror to control collimation of light reflecting from the mirror.
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Dependencies are inferred from the claim text.