Hybrid diffractive/refractive lens
First Claim
1. An optical lens for collimating a divergent input light, comprising:
- a) a substantially spherical front lens surface; and
b) a substantially planar back lens surface having a binary optic diffractive element etched thereon wherein said back lens surface has been formed such that the optical path length travelled by each ray of said divergent input light from a source of said divergent input light to a predetermined collimation plane is substantially equal.
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Accused Products
Abstract
A hybrid lens for collimating, with low optical aberrations, an asymmetrically diverging input wavefront. The hybrid lens has a front surface which serves to diffract the input wavefront and a back surface which serves to refract the wavefront. Embodiments are described comprised of either a single plano-convex optical lens or a pair of lenses, one of which is a plano lens and the other or which is plano-convex. In either alternative, the convex surface is spherical. The planar surface of the single plano-convex lens or the back lens surface of the plano lens is optimized such that each ray of light from a diverging input light source will travel the same optical path length in reaching a predetermined collimation plane. This optimization is done by means of binary optic technology which uses a reactive-ion etch to form the requisite eight-level binary optic diffraction pattern. The widths of the fringe patterns generated by the three masks determined by calculations of the optical path difference between on-axis and off-axis rays which are traced through the hybrid lens.
14 Citations
17 Claims
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1. An optical lens for collimating a divergent input light, comprising:
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a) a substantially spherical front lens surface; and b) a substantially planar back lens surface having a binary optic diffractive element etched thereon wherein said back lens surface has been formed such that the optical path length travelled by each ray of said divergent input light from a source of said divergent input light to a predetermined collimation plane is substantially equal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of producing a collimated output beam of light from a divergent input light source comprising the steps of:
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a) providing a plano-convex lens having a first planar side forming a back lens surface and a substantially spherical second convex side forming a front lens surface;
said planar side having a binary optic diffractive element etched thereon; andb) directing said divergent input light source at said first planar side of said plano-convex lens such that the optical axis of said divergent input light source is positioned substantially through the center of said plano-convex lens. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification