Extended working range illumination system for an imaging-based bar code reader

A bar code reader for imaging a target bar code comprising:

• a) imaging assembly for imaging and decoding a bar code;
• b) a range assembly for determining a distance from the imaging assembly to the target bar code;
• c) illumination assembly for emitting illumination for imaging the target bar code the imaging assembly including:
• 1) an illumination source energizable to emit a first illumination pattern when a distance to the target bar code is less than a predetermined value;
• and
• 2) the illumination source energizable to emit a second illumination pattern when the distance to the target bar code is greater than the predetermined value, wherein the second illumination pattern is more concentrated than the first illumination pattern.

A reading apparatus for decoding areas of differing light reflectivity on a target comprising:

• a) an illumination source for producing a first illumination pattern;
• b) a detector for measuring a distance from said reading apparatus and a target object;
• c) a system threshold;
• d) a comparator for evaluating the measured distance against said threshold;
• and
• e) a second illumination pattern that is activated when said measured distance is greater than said threshold.

A method for imaging a target bar code, the steps of the method comprising:

• a) determining a distance from the imaging assembly to the target bar code;
• b) energizing an illumination assembly for emitting illumination for imaging a target bar code an illumination source energizable to emit a first illumination pattern when a distance to the target bar code is less than or equal to a predetermined value;
• and
• c) the illumination source energizable to emit a second illumination pattern when the distance to the target bar code is greater than the predetermined value, wherein the second illumination pattern is more concentrated than the first illumination pattern.

A method of reading a target article comprising:

• a) projecting a low power illumination pattern from an imaging system across a target article;
• b) reflecting said low power illumination pattern from said target article to a lens located in said imaging system;
• c) directing said reflected illumination across a pixel array generating an image;
• d) reading said image produced in the pixel array in a CCD imager;
• e) comparing a measured distance from said imaging system to said target article against a threshold of said imaging system;
• f) sustaining the low power illumination pattern if when comparing the measured distance against the threshold of imaging system its determined that the measured distance is less than said threshold;
• and
• g) employing a concentrated illumination pattern if when comparing the measured distance against the threshold of imaging system its determined that the measured distance is greater than said threshold.

An automatic imaging system having a first illumination pattern that is directed at a target object when the system is actuated and an imaging system including a pixel array, a focusing lens to focus an image of the target object onto the pixel array, the automatic imaging system comprising:

• a) software and/or circuitry for analyzing an image of the illumination reflected from the target object and projected onto the pixel array by the lens;
• b) an analytical technique to establish a measured variable;
• c) an imaging system threshold;
• d) a comparator for evaluating said measured variable to said imaging system threshold;
• and
• e) a second concentrated illumination pattern that is activated when said measured variable is greater than said imaging system threshold.