Alan W Johnston

US Patent:

48842435, Nov 28, 1989

Filed:

Feb 19, 1988

Appl. No.:

7/157692

Inventors:

Alan R. Johnston - La Canada CA
Robert H. Nixon - Sunland CA
Larry A. Bergman - Van Nuys CA
Sadik Esener - La Jolla CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

G11C 800

US Classification:

365234

Abstract:

A random access memory addressing system utilizing optical links between memory and the read/write logic circuits comprises addressing circuits including a plurality of light signal sources, a plurality of optical gates including optical detectors associated with the memory cells, and a holographic optical element adapted to reflect and direct the light signals to the desired memory cell locations. More particularly, it is a multi-port, binary computer memory for interfacing with a plurality of computers. There are a plurality of storage cells for containing bits of binary information, the storage cells being disposed at the intersections of a plurality of row conductors and a plurality of column conductors. There is interfacing logic for receiving information from the computers directing access to ones of the storage cells. There are first light sources associated with the interfacing logic for transmitting a first light beam with the access information modulated thereon.

US Patent:

44790538, Oct 23, 1984

Filed:

Mar 11, 1981

Appl. No.:

6/242797

Inventors:

Alan R. Johnston - La Canada CA

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

G01S 902

US Classification:

250221

Abstract:

An optical proximity sensor for optically detecting an object within a predetermined detection volume. More specifically, an optical proximity sensor is disclosed having an illuminator assembly including an illuminator lens (55) and a plurality of light-emitting diodes (53) located at first predetermined positions along the focal plane (54) of the illuminator lens (55). A detector assembly including a detector lens (65) and a plurality of photodiodes (60) located at second predetermined positions along the focal plane of the detector lens (65) is also provided. The two lenses are spaced apart a predetermined distance in accordance with the configuration of the light-emitting diodes (53) and the photodiodes (60) in order to define a predetermined detection volume. Each light-emitting diode has a corresponding photodiode, and their relative positions on their respective focal planes determine the detection volume defined by their overlapping fields of view. Thus by correctly positioning one light-emitting diode/photodiode pair with respect to each other, all the other pairs will be correctly positioned due to their predetermined locations on their respective focal planes.