Optical assembly and apparatus employing same using an aspherical lens and an aperture stop
First Claim
1. An optical apparatus, comprising:
- light sensing means for detecting indicia, said light sensing means having an active viewing surface;
a single element field corrected lens means, disposed between said light sensing means and said indicia, having an optical axis and a radial dimension that is orthogonal with said optical axis; and
an aperture stop means spaced apart form said lens means for constraining light beams originating from respective first and second regions of the indicia and reaching first and second regions of said active viewing surface to traverse first and second exclusive portions of said lens means;
whereby light beams originating from all points on said indicia focus onto said active viewing surface.
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Accused Products
Abstract
There is disclosed an simplified apparatus that enables optical scanners to achieve minimum field curvature and at the same time provide uniformly distributed light on an image sensor. A single element lens, preferably an aspherical lens made of a plastic material is combined with an aperture stop. The combination is capable of reducing lens aberrations and minimizing image field curvature for an object plane that contains indicia to be scanned or read. A suitably demagnified image of the indicia is focused onto an image sensor such as a CCD array. The spatial light distribution function in the image plane can be equalized by an attenuator, such as a neutral density filter or a slit, suitably configured to compensate for the reduced optical efficiency at large field angles. An aspherical lens containing a dye or a cold mirror can be used for limiting light transmission to a range of wavelengths.
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Citations
33 Claims
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1. An optical apparatus, comprising:
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light sensing means for detecting indicia, said light sensing means having an active viewing surface; a single element field corrected lens means, disposed between said light sensing means and said indicia, having an optical axis and a radial dimension that is orthogonal with said optical axis; and an aperture stop means spaced apart form said lens means for constraining light beams originating from respective first and second regions of the indicia and reaching first and second regions of said active viewing surface to traverse first and second exclusive portions of said lens means; whereby light beams originating from all points on said indicia focus onto said active viewing surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A bar code scanner, comprising:
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a housing; light sensing means for detecting light reflected from a bar code symbol nd for generating an analog signal in response thereto that is indicative of the bar-space pattern of said bar code symbol, said light sensing means having an active viewing surface; signal processing means, composed to said light sensing means, for processing said analog signal; a single element field corrected lens, disposed between said light sensing means and said bar code symbol, having an optical axis and a radial dimension that is orthogonal with said optical axis; and an aperture stop means spaced apart from said lens for constraining light beams originating from respective first and second regions of the bar code symbol and reaching first and second regions of said active viewing surface to traverse first and second exclusive portions of said lens; whereby light rays originating from all points on said bar code symbol focus onto said active viewing surface. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification