Pseudo telecentric optical storage system
AssigneeTerastor Corporation
InventorsBernard W. Bell, Jr., Amit Jain
Life of this patent
Estimating the term…
Abstract
An electro-optical storage system based on air-bearing-suspended optical head in a near-field configuration. The optical head effects a lens having front and rear focal planes. The head is spaced from an optical medium by a fraction of a wavelength. An imaging lens is positioned relative to the optical head so that the image of a beam steering element is at a focal plane of the optical head close to the imaging lens to form a telecentric system to minimize beam walk. More preferably, the imaging lens is positioned to deviate the image plane of the beam steering element away from the focal plane of the optical head by a desired spacing to form a pseudo telecentric system to minimize energy asymmetry in the reflected beam.
Claims15
An optical storage system, comprising:
- a medium holder adapted to hold an optical storage medium at a specified position;
- an optical beam steering element disposed relative to said medium holder and having an optical steering plane to receive an optical beam and direct said optical beam to a desired direction by steering said optical steering plane;
- an optical head disposed in a path of said optical beam to couple optical energy to and from said optical storage medium, said optical head configured as a lens assembly with a first and second focal planes which includes a solid immersion lens, wherein said first focal plane is closer to said optical beam steering element than said second focal plane;
- and
- an imaging lens disposed between said optical beam steering element and said optical head to image said optical steering plane of said optical steering element to an image plane that is spaced from said first focal plane to form a pseudo telecentric imaging system formed by said imaging lens and said lens assembly of the optical head, a spacing between said image plane and said first focal plane being set at a value to achieve a substantially symmetric energy distribution in a reflected beam from said optical medium and said lens assembly.
A near-field optical system, comprising:
- a medium holder adapted to hold an optical storage medium at a specified position;
- an optical steering beam element disposed relative to said medium holder, receiving an optical beam and directing said optical beam from an optical steering plane;
- an objective lens located relative to said optical beam steering element in a path of said optical beam;
- a near-field lens disposed between said objective lens and said optical storage medium and positioned from said optical storage medium by a spacing less than one wavelength of said optical beam, wherein said near-field lens and said objective lens collectively effects a lens assembly with first and second focal planes wherein said first focal plane is closer to said optical beam steering element than said second focal plane;
- and
- an imaging lens disposed between said optical steering element and said objective lens to image said optical steering plane of said optical steering element to an imaging location that is positioned away from said first focal plane by a spatial deviation to achieve a substantially symmetric energy distribution in an optical beam being reflected from said optical medium and transmitting through said lens assembly.
Dependencies are inferred from the claim text.