Optical system for data reading having wide range of focus
First Claim
1. A method for data reading comprising the steps ofprojecting a beam of light along an outgoing optical path;
- passing the optical beam through a diffractive module having a first outer aperture and a second inner aperture, the second inner aperture being formed by at least one panel which is partially light transmissive.
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Accused Products
Abstract
An optical system and method for data reading in which a light source generates an optical beam directed toward an object to be read and a variable aperture mechanism positioned in the outgoing light path establishes at least two separate focal planes. The variable aperture device may comprise a variable aperture system in which the size of the aperture is selectively varied about a range within the diffractive limit of the light beam. A preferred aperture mechanism is a liquid crystal aperture with one or more aperture regions which are selectively or consecutively activated. The optical system therefore establishes two or more separate waist locations from a single light source resulting in greater depth of field or multiple depths of field.
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Citations
19 Claims
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1. A method for data reading comprising the steps of
projecting a beam of light along an outgoing optical path; passing the optical beam through a diffractive module having a first outer aperture and a second inner aperture, the second inner aperture being formed by at least one panel which is partially light transmissive. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A laser scanner for bar code reading, comprising:
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a discrete light source generating a laser beam along an outgoing optical path; a focusing lens positioned in the outgoing optical path for focusing the laser beam to a waist at a given location; a diffractive aperture device positioned in the outgoing optical path, the diffractive aperture device having a first outer aperture and a second inner aperture, the second inner aperture being formed by at least one panel, the panel being comprised of a material which allows for partial light transmission therethrough. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A data reading device, comprising:
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a light source generating a laser beam along an outgoing optical path; a focusing lens positioned in the outgoing optical path for focusing the laser beam to a waist at a given location; a diffractive aperture device positioned in the outgoing optical path, the diffractive aperture device having an outer aperture and an inner aperture, the inner aperture being formed by at least a first panel, the first panel being partially light transmissive. - View Dependent Claims (17, 18, 19)
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Specification