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:
Jul. 06, 1993
Filed:
May. 18, 1992
Lyle R Powers, Boulder, CO (US);
Rikk Crill, Longmont, CO (US);
Avalon Engineering, Inc., Boulder, CO (US);
Abstract
A semiconductor wafer cassette mapper detects the presence absence of a semiconductor wafer in a particular corresponding pair of slots of the wafer cassette, as well as a cross slotted condition in which a wafer is not aligned in a corresponding pair of slots. The wafer cassette mapper includes a base member for receiving a standard slotted wafer cassette, the base member including transmitter and receiver modules on opposite sides thereof. The transmitter and receiver modules include like pluralities of inwardly facing, aligned light apertures. Each of the light apertures in the transmitter module contains a light emitting infrared transmitter, and each of the light apertures in the receiver module contains an infrared receiver. Control circuitry selectively activates the light emitting transmitters for a predetermined period of time and selectively interrogates the infrared receivers during that period of time to determine if a particular receiver has received light transmitted by a selected transmitter. Logic circuitry then processes this information to determine if a particular wafer position is empty and if a cross slotted condition exists.