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. 09, 2003
Filed:
Nov. 06, 2001
Naomi Ishizuka, Tokyo, JP;
Akihito Matsumoto, Tokyo, JP;
Eiichi Kono, Tokyo, JP;
Motoji Suzuki, Tokyo, JP;
Akihiro Sato, Tokyo, JP;
Hiroshi Matsuoka, Tokyo, JP;
Masafumi Kanai, Shizuoka, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a circuit board having lands each of which has a through hole through which a lead of an electrical part is inserted, the lead and the land being mounted in the circuit board by using lead-free solder , the width of the land corresponding to the difference in radius between the land and the through hole is set to about 0.40 mm or more. The width of the land is set to such a value that the land exfoliation due to the solidification/shrinkage of the lead-free solder and the shrinkage of the circuit board in the thickness direction can be prevented. The circuit board has circuit wires at least on both the surface and the back surface.