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:
Sep. 27, 1977
Filed:
May. 03, 1976
Junzo Tanaka, Fujiidera, JA;
Toshio Kai, Yamatokoriyama, JA;
Matsushita Electric Industrial Co., Ltd., Osaka, JA;
Abstract
A structure of a microwave oven door screen which facilitates the observation of the inside of a heating cavity and enhances the safety against the electromagnetic wave leakage and durability. A door screen of this type generally comprises a pair of transparent plates and an electromagnetic wave shielding material interposed therebetween. The present door screen uses a punched metal plate as the electromagnetic shielding material made of aluminum having a thickness of 0.1 to 0.35 mm, an aperture diameter of 1.2 mm or less and a ratio of the aperture diameter to a center-to-center distance of an aperture of 0.67 to 0.85, these parameters being chosen such that an aperture rate of more than 40% is assured and the electromagnetic wave leakage through the door screen is effectively prevented (to meet the Regulations of U.S. Department of Health, Education, and Welfare) and a strain due to continuous mechanical treatment of the punched metal plate is minimized.