Printed circuit board with thin film switches for a keyboard

• US 20070163866A1
• Filed: 01/17/2006
• Published: 07/19/2007
• Est. Priority Date: 01/17/2006
• Status: Active Grant

• Current Assignee: Huo-Lu Tsai
• Original Assignee: Huo-Lu Tsai
• Inventors: Tsai, Huo-Lu
• Granted Patent: US 7,304,860 B2
• Time in Patent Office: Days
• US Class Current: 200/292
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 2227/018 Printed contacts; Metal foil
• CPC Class Codes: H01H 2229/002 Screen printing

Abstract

A printed circuit board with thin film switches for a keyboard including an upper board having multiple circuit lines, an insulating separation defining multiple through holes, a lower board having multiple circuit lines and multiple thin film switches mounted on the upper and lower boards. The thin film switch has two thin film conductive elements respectively formed on the upper and lower boards and correspond to one of the through holes in the insulating separation. Each thin film conductive element has a center conductor, at least two outer conductors formed adjacent to the center conductor, and at least two conductive lines connected to the center and outer conductors. With such an arrangement, the areas of the center and outer conductors will be reduced, surfaces of the conductors are even in the curing procedure of fabricating upper or lower board to keep a stable touching sensitivity.

Claims

1. A printed circuit board with thin film switch for a keyboard, comprising:

an upper board having multiple circuit lines;

a lower board having multiple circuit lines;

an insulating separation positioned between the upper and lower boards and defining multiple through holes; and

at least one thin film switch, each has two thin film conductive elements formed respectively on the upper and lower boards and connected to the circuit lines, wherein each thin film conductive element comprises;

a center conductor aligned with one of the through holes in the insulating separation;

at least two outer conductors formed adjacent to but electrically isolated from the center conductor and aligned with a corresponding through hole, wherein each outer conductor is adapted to be connected to the circuit lines of the upper or lower board; and

at least two conductive lines connected to the center conductor and respectively to the at least two outer conductors.

2. The printed circuit board as claimed in claim 1, wherein the two outer conductors are symmetrically formed adjacent to the center conductor and are formed of a curved shape.

3. The printed circuit board as claimed in claim 2, wherein each thin film conductive element is formed to an invert-S shape.