Honeywell G.m.b.h.

Digital Equipment Corporation

James W Howard

Neville K Lee

David L Jungkman

Timothy E White

Irving R Abel

David M Reilly

Ben Godfrey

Walter Hrytsay

Patrick K Tan

A method and apparatus for measuring the focus and tracking of a light beam on a medium in an optical data storage system. A split lens, comprising two halves of a lens separated along the optical axis and displaced from each other along the plane of the cut, is used to focus the light reflected or refracted from the medium onto a quad-cell. The quad cell comprises four light sensors arranged in four quadrants about a center point. According to the invention, the amount of light incident on quadrants of the quad-cell indicates the focus and alignment of the light beam on the medium. In accordance with another aspect of the invention, the above apparatus is used to measure the collimation or distribution of intensity of a light beam. Another aspect of the invention is the manufacture of the split lens. A lens is sawed into two halves and the halves are mounted using a housing displaced from each other along the plane of the cut.

Split lens displaced long from each other along plane of cut

A rotary actuator for an optical head comprises a pair of reflectors mounted respectively on the end of the arm and on the pivot axis to define an optical path via the arm to an optical disk for an external beam directed along the pivot axis. Special arm geometry reduces variable head skew and consequent image rotation. A multiple platter design features optical switches effectively aligned on the pivot axis.

Rotary head actuator for optical disk

A micro-objective lens is carried on an air bearing slider with an optical passage through which the lens focuses an energy beam onto a spot on an optical data storage medium. The slider accomplishes automatic focusing. An RF coil is affixed to the slider facing the storage medium and surrounding the beam axis. The proximity of the coil lowers power switching requirements.

Optical head with flying lens

A method and apparatus for measuring the focus and tracking of a light beam on a medium in an optical data storage system. A split lens, comprising two halves of a lens separated along the optical axis and displaced from each other along the plane of the cut, is used to focus the light reflected or refracted from the medium onto a quad-cell. The quad cell comprises four light sensors arranged in four quadrants about a center point. According to the invention, the amount of light incident on quadrants of the quad-cell indicates the focus and alignment of the light beam on the medium. In accordance with another aspect of the invention, the above apparatus is used to measaure the collimation or distribution of intensity of a light beam. Another aspect of the invention is the manufacture of the split lens. A lens is sawed into two halves and the halves are mounted using a housing displaced from each other along the plane of the cut.

Method and apparatus for detecting focus and tracking errors

An optical mass storage device for use in data processing systems. Two or more lasers provide separate read and write laser beams having different wavelengths. The read and write laser beams can be orthogonally polarized. A polarizing beam splitter combines the read and write beams along a common optical path to an optical head. The head directs the combined beam to a magneto-optic storage medium. A read beam is reflected back by the medium to the common path through the head. A dichroic beam splitter disposed in the common path between the head and the polarizing splitter reflects the read beam to an optical detector. If more than one write laser is necessary, a second dichroic splitter can be used to combine the multiple write beams and the read beam.

Magneto-optical data recording device using a wavelength and

A shield for limiting the radiation received by an array of detectors along the length of the detector array of an electromagnetic radiation detection system to radiation provided to the detectors by the optics of the system. The shield comprises a pair of glass rods mounted in a parallel relationship to each other and to the linear direction of the array and forming an aperture along the length of the array so as to shield the elements of the array from electromagnetic radiation generated outside the field-of-view of the detectors.

Glass cold shield

A prism cold shield adaptable to an infrared detector system comprising a prism-shaped substrate having an upper portion partially coated with opaque material and a lower portion partially coated with opaque material wherein windows formed by the upper and lower coatings defined the field of view for a plurality of infrared detectors thereby cold shielding the detectors in the linear direction of the detector array.

Prism cold shield

An improved composite lens is described which provides higher optical transmittance and lower weight and cost than a conventional ZnSe/ZnS doublet. A method of manufacture is also described which uses a process of chemical vapor disposition of one material (e.g. ZnSe) on a blank of another material (e.g. ZnS), combined with well-known optical machining and polishing processes to obtain the desired curvatures on the lens surfaces.

Apparatus and method for fabricating a sandwich lens

A multi-element spectral filter with curved interior surfaces which provides uniform angular response and is particularly well-suited for use in wide field of view optical detection systems.

Multi-element spectral filter with curved interior surfaces

An improved optical system for thermal imaging systems using wide field of view optics in conjunction with large detector arrays in which a detector cold shield, system aperture stop and scanning subassembly are placed in substantially the same location such that the size of the scanning optics is minimized and cold shielding efficiency is maximized.

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Natick, MA, United States of America

James W Howard