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. 25, 2000
Filed:
May. 04, 1998
Hiroaki Saeki, Shirane-machi, JP;
Teruo Asakawa, Ryuo-cho, JP;
Tokyo Electron, Ltd., Tokyo-To, JP;
Abstract
A plurality of projections 21 is disposed on a inner surface of a lid 20 which is detachably attached to a carrier body 10. Each projection 21 has a tapered end part 22 with inclined surfaces 23, 24. The surfaces 23, 24 are in the form of semitransparent mirror. A Light emitting device 47 projects light beam which travels horizontally to the projection 21 from outside of the lid 20. When a wafer is not present in slots 15 of the carrier body, the light beam travels to upper and lower adjacent photoelectric devices 48, 48 via the upper and lower adjacent projections 21. The semitransparent mirror 23, 24 changes the light beam traveling direction. When the wafer is present in the slots 15, the light beam is intercepted by the wafer, and the photoelectric devices 48 does not receive the light beam. In aforementioned manner, whether a wafer is present or not in the slots 15 can be detected.