California Institute of Technology

The United States of America As Represented by the Administrator of the

Alan R Johnston

Robert H Nixon

Larry A Bergman

Sadik Esener

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. First light detectors are associated with the storage cells for receiving the first light beam, for generating an electrical signal containing the access information, and for conducting the electrical signal to the one of the storage cells to which it is directed. There are holographic optical elements for reflecting the first light beam from the first light sources to the first light detectors.

Multi-port, optically addressed RAM

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. Additionally, a combination of optical proximity sensors, according to the invention, is disclosed wherein the sensors can be used in conjunction with a vehicle to provide a safety system for warning an operator when an object is within a volume defined by the proximity sensor combination.

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La Canada, CA, United States of America

Alan R Johnston