Pushbutton switch

• US 5,664,667 A
• Filed: 07/17/1996
• Issued: 09/09/1997
• Est. Priority Date: 10/26/1995
• Status: Expired due to Term

• Current Assignee: Sunarrow Ltd.
• Original Assignee: Sunarrow Ltd.
• Inventors: Kenmochi, Yoshio
• Primary Examiner(s): Walczak, David J.
• Application Number:
  US08/683,771
• Time in Patent Office: 419 Days
• Field of Search: 200/512, 200/305, 200/304, 200/314, 200/313, 200/516, 200/513, 200/514, 200/310
• US Class Current: 200/314
• 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 2219/06 Reflector
• CPC Class Codes: H01H 2221/07 transparent
• CPC Class Codes: H01H 2239/004 High frequency adaptation or shielding
• CPC Class Codes: H01H 2239/008 Static electricity considerations

Abstract

A pushbutton switch is described which has a printed wiring board and a keypad arranged above the printed board, wherein the keypad has a non-working portion and a working portion made of translucent silicone rubber or thermoplastic elastomer in which the upper surfaces of the non-working portions only are covered with an opaque film, with an underside surface thereof covered by an insulating resin film so as to form an electrically conductive light-reflecting layer which is grounded to an earth portion.

Claims

1. A pushbutton switch, comprising:

a printed-wiring board equipped with a light source;

a keypad which is arranged above the printed-wiring board, the keypad including a non-working portion having an upper surface, an underside, and a working portion wherein both the working and non-working portions are made of translucent silicone rubber, in which said upper surface of the non-working portion, except for the working portion of the keypad, is covered with an opaque film, with an underside surface of said opaque film being covered by an insulating resin film which forms an electrically conductive light-reflecting layer, and in which the electrically conductive light-reflecting layer is grounded by being connected to an earth portion; and

a plastic dome sheet arranged between the printed-wiring board and the keypad, the plastic dome sheet having a dome portion which rises in a dome shape at a position corresponding to the working portion;

in which an electrically conductive light-reflecting layer is formed over the entire upper surface of the dome sheet, with the electrically conductive light-reflecting layer being grounded by being connected to an earth portion.

2. A pushbutton switch, comprising:

a printed-wiring board equipped with a light source;

a keypad which is arranged above the printed-wiring board, the keypad including a non-working portion having an upper surface and an underside, and a working portion wherein both the working and non-working portions are made of a thermoplastic elastomer, in which said upper surface of the non-working portion, except for the working portion of the keypad, is covered with an opaque film, with an underside surface of said opaque film being covered by an insulating resin film which forms an electrically conductive light-reflecting layer, and in which the electrically conductive light-reflecting layer is grounded by being connected to an earth portion; and

a plastic dome sheet arranged between the printed-wiring board and the keypad, the plastic dome sheet having a dome portion which rises in a dome shape at a position corresponding to the working portion;

in which an electrically conductive light-reflecting layer is formed over the entire upper surface of the dome sheet, with the electrically conductive light-reflecting layer being grounded by being connected to an earth portion.