The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 04, 1989
Filed:
Jan. 28, 1987
Joseph Maserjian, La Crescenta, CA (US);
California Institute of Technology, Pasadena, CA (US);
Abstract
Multiple quantum well (MQW) structures (24) are utilized to provide real-time, reliable, high-performance, optically-addressed spatial-light modulators (SLM) (10, 10'). Several embodiments are provided, including combination of MQW structures with PIN photodiodes of GaAs (12) or Si (12') to form two-dimensional arrays of pixel elements (92) on a single chip (90). In another embodiment, the optically-addressed SLM (50) comprises a vertical stack of MQW layers (52) within the penetration depth of an optical write signal (36), a plurality of space charge barriers (52b) having predetermined tunneling times by control of doping and thickness, whereby modulation sensitivity is high and no external voltage source is required. In yet another embodiment, the optically-addressed SLM (70) comprises a multiplicity of quarter-wave layers (72, 74) whose index of refraction is changed by changes in in the fields at the boundaries (80) responsive to the photocurrent generated by the incident write signal. The changes are read by use of a read signal (38) of a wavelength that is resonantly reflected (78) from the quarter-wave layers.