Computer memory
AssigneeMassachusetts Institute of Technology
InventorsAli Javan, Charles F. Davis, Jr.
Life of this patent
Estimating the term…
Abstract
A memory system is shown in which communication to and from memory cells is effected by optical beams. Memory cells are shown employing elements with negative resistance and operating in either of two stable modes. Other memory cells are shown employing subharmonic oscillators operating in either of two phase relationships. The memory cells and systems permit extremely fast operation.
Claims20
In a memory system having an assembly of memory cells with identifying address values, each cell capable of assuming alternatively either of two states, the states defining the value of information stored in the cell, the improvement comprising an array of memory cells spatially arranged on a substrate in accordance with identifying address values, each cell comprising resonant at frequency f, an element with a non-linear characteristic, and an antenna structure responsive to incident radiation of frequency 2f, said non-linear element, antenna structure, and resonant circuitry being connected to form a sub-harmonic oscillator driven by radiation incident on said antenna structure, said oscillator oscillating at frequency f alternatively in two stable states of two distinct phase relations with respect to said radiation of frequency 2f, said circuitry being arranged and connected so that when said antenna structure is stimulated by optical radiation of frequency f having a first of two distinct phase relationships said circuitry is coerced into a first of said stable states and when said antenna structure is stimulated by optical radiation of frequency f having a second of two distinct phase relationships said circuitry is coerced into a second of said stable states.
In a memory system having an assembly of memory cells with identifying address values, each cell capable of assuming alternatively either of two states, the states defining the value of information stored in the cell, the improvement comprising an array of memory cells spatially arranged on a substance in accordance with identifying address values, each cell comprising circuitry including an element with a negative resistance characteristic connected to a load resistor to operate stably alternatively at either of two points of its characteristic, said two operating points being associated respectively with the value of data stored in the memory cell, switching means connected to said circuitry responsive to incident optical radiation of two alternative characterizations switching said circuitry to a corresponding point of operation, and a light-emitting diode connected to said circuitry to be actuated only during switching of said circuitry from the first of said operating points to the second.
Dependencies are inferred from the claim text.