Illumination system including convex/concave lens for an imaging-based bar code reader

An illumination apparatus for an imaging-based bar code reader comprising:

• illumination means for directing illumination through a focusing means to generate an illumination pattern directed toward a target object;
• and
• the focusing means for generating the illumination pattern wherein the illumination pattern includes variation in illumination intensity projected toward the target object such that a central portion of the illumination pattern has relatively lower illumination intensity and outer peripheral portions of the illumination pattern on opposite sides of the central portion have relatively higher illumination intensity.

An illumination system for an imaging-based bar code reader including an imaging system, the illumination system comprising:

• a first illumination assembly and a second illumination assembly, each of the first and second assemblies including an illumination source and a focusing lens, the illumination source directing illumination through the focusing lens and the first and second illumination assemblies together generating an illumination pattern directed toward a target object, the illumination pattern including variation in illumination intensity;
• the first assembly being on one side of an optical axis of the imaging system and the second assembly being on the opposite side of the optical axis of the imaging system;
• and for each of the first and second assemblies, the focusing lens includes a first optical surface, the first optical surface including a first region having a residual surface profile that is concave with respect to a curvature of a best fit cylinder of the focusing lens and a second region that is convex with respect to the curvature of the best fit cylinder.

An illumination apparatus for an imaging-based bar code reader comprising:

• an illumination source directing illumination through a focusing lens to generate an illumination pattern directed toward a target object;
• and
• the focusing lens including a first optical surface, the first optical surface including a central region defining a first optical power and a peripheral region spaced from the central region defining a second optical power, the second optical power being a more positive optical power than the first optical power and the generated illumination pattern including variation in illumination intensity.