Discovision Associates

Applied Magnetics, LLC

Opto Tech Corporation

Ivan Prikryl

Hollis O'Neal Hall

Curtis A Shuman

Hollis O'Neal Hall, Ii

Focusing means to focus a beam upon a reflective-transmissive surface. Reflecting means to reflect a central portion of the beam from the reflective-transmissive surface. Transmitting means to transmit a portion of the beam that lies outside the central portion. Receiving means to receive the transmitted portion of the beam and combining means to combine the reflected central portion of the beam with a test beam to generate an interference pattern.

Method and apparatus for beam directing

An interferometer includes a beamsplitter for splitting a source beam into a test beam and a reference beam, an imaging device for detecting an interference pattern, a mirror disposed in a path of the test beam for reflection of the test beam toward the imaging device, a micromirror disposed in a path of the reference beam for reflection of a portion of the reference beam toward the imaging device, and a focusing mechanism disposed for focusing the reference beam on the micromirror. The micromirror has a lateral dimension not exceeding the approximate lateral dimension of a central lobe of the reference beam focused thereon by the focusing mechanism. A spatial filter for reducing effects of aberration in a beam includes a reflector disposed upon a transparent base wherein the reflector has a lateral dimension not exceeding the approximate lateral dimension of a central lobe of the spatial intensity distribution of the beam focused upon the reflector.

Interferometer having a micromirror

An interferometer includes a beamsplitter for splitting a source beam into a test beam and a reference beam, an imaging device for detecting an interference pattern, a mirror disposed in a path of the test beam for reflection of the test beam toward the imaging device, a micromirror disposed in a path of the reference beam for reflection of a portion of the reference beam toward the imaging device, and a focusing mechanism disposed for focusing the reference beam on the micromirror. The micromirror has a lateral dimension not exceeding the approximate lateral dimension of a central lobe of the reference beam focused thereon by the focusing mechanism. A spatial filter for reducing effects of aberration in a beam includes a reflector disposed upon a transparent base wherein the reflector has a lateral dimension not exceeding the approximate lateral dimension of a central lobe of the spatial intensity distribution of the beam focused upon the reflector. A method of filtering a beam in a wavefront measurement system is also provided. This method includes focusing the beam, reflecting a particular first portion of the focused beam, and transmitting a second portion of the beam. In accordance with Office policy under M.P.E.P. Sec. 608.01(b), Applicant submits herewith as a part of the submitted Substitute Specification, a separate sheet with the subject Abstract as currently rewritten.

An optical system for determining aberration in a source beam by comparison of a test beam with a reference beam. The optical system includes a test source for producing a source beam having a spacial intensity distribution including an aberration component, a wavefront analyzer for processing a fringe signal associated with the aberration component, and an interferometer. The interferometer is provided with a beamsplitter for splitting the source beam into a test beam and a reference beam, an imaging device for detecting the test beam and the reference beam, and a mirror disposed in a test beam path for reflecting the test beam toward the imaging device. The interferometer also includes a micromirror disposed in a reference beam path for reflecting a portion of the reference beam toward the imaging device and a piezoelectric translator operatively linked to the mirror and controlled by the wave front analyzer. The mirror is capable of moving relative to the path of the test beam. The micromirror has a lateral dimension not exceeding the approximate lateral dimension of a central lobe of the reference beam as focused thereon by focusing means so that when the test beam is reflected by the mirror and the portion of the reference beam is reflected by the micromirror, the reflected test beam and the reflected portion of the reference beam are both incident upon the imaging device forming an interference pattern including fringes which are converted into the fringe signal.

Optical test system including interferometer with micromirror and

An adjustable optical system for determining aberration in a source beam by comparison of a test beam with a reference beam. The system includes a test source for producing a source beam having a spacial intensity distribution including an aberration component, a wavefront analyzer for processing a fringe signal associated with the aberration component, and an interferometer interposed between the test source and wavefront analyzer. The interferometer includes a beamsplitter for splitting the source beam into a test beam and a reference beam, a mirror disposed in the test beam path, and a micromirror disposed in the reference beam path. The micromirror reflects a central portion of the reference beam toward an imaging device and allows an outer portion of the reference beam to pass thereby. The interferometer is also provided with an alignment image assembly for collecting and detecting the outer portion of the reference beam so that the micromirror and test source may be independently adjusted relative to the central and outer portions of the reference beam.

Adjustable optical test apparatus including interferometer with

A focus sensing apparatus for determining the focus of an illuminating beam relative to an optical disk is disclosed herein. In one preferred embodiment, a light source generates a linearly polarized beam which is collimated by a collimating lens. The collimated beam is then converged by an objective lens onto the surface of the optical disk. The disk reflects the illuminating beam focused thereon back through the objective lens to a polarization beam splitter. A portion of the optical energy incident on the beam splitter is then redirected to form a servo beam, wherein the degree of collimation of the servo beam is indicative of the focus position of the illuminating beam. A beam separation module having a reflectivity which varies in response to the angle of incidence of optical energy thereon is positioned to intercept the servo beam. The beam separation module is operative to separate the servo beam into two beams which could be transmitted and reflected beams of substantially similar shape and intensity. Electrical signals produced by photodetective elements in response to incidence of the transmitted and reflected beams thereon may then be used to differentially generate a focus error signal. Gain control circuitry is provided to compensate for asymmetrical changes in beam intensity and maintain balanced detector channels during the generation of the differential focus error signal.

Focus sensing apparatus using electrical AGC to enhance differential

An apparatus for evaluation of radiation beam geometry that finds application in determining the focus of an illuminating beam relative to an optical disk is disclosed herein. In one preferred embodiment, a light source generates a linearly polarized beam which is collimated by a collimating lens. The collimated beam is then converged by an objective lens onto the surface of the optical disk. The disk reflects the illuminating beam focused thereon back through the objective lens to a beam splitter. A portion of the optical energy incident on the beam splitter is then redirected to form a servo beam, wherein the degree of collimation of the servo beam is indicative of the focus position of the illuminating beam. A beam separation module, based on frustrated total reflection, having a reflectivity which varies in response to the angle of incidence of optical energy thereon is positioned to intercept the servo beam. The beam separation module is operative to separate the servo beam into transmitted and reflected beams of substantially similar shape and intensity. Electrical signals produced by photodetective elements in response to incidence of the transmitted and reflected beams thereon may then be used to generate a focus error signal.

Focus sensing apparatus utilizing a reflecting surface having variable

An optical data storage system includes a laser which is focused on an optical disk by an objective lens. A tracking actuator and a focus actuator move the objective lens about a tracking axis and focus axis respectively. The tracking and focus actuators respond to signals provided by a focus and tracking detector. The focus and tracking detector is formed by four photodetectors which are electrically isolated from one another. The third and fourth photodetectors are disposed about the outer peripheries of the first and second photodetectors, respectively, about an axis. Each photodetector emits an electrical signal representative of the radiation detected thereon.

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Colorado Springs, CO, United States of America

Ivan Prikryl