Electricity: circuit makers and breakers – Electric switch details – Cases and bases
Reexamination Certificate
1999-05-10
2001-03-06
Donovan, Lincoln (Department: 2832)
Electricity: circuit makers and breakers
Electric switch details
Cases and bases
C200S314000
Reexamination Certificate
active
06198060
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The present invention relates to an EL-combined sheet switch to be used, for example, in an inputting device for portable telephones, electronic pocket-books, etc.
2. Description of the Related Art
Portable appliances such as portable telephones, electronic pocketbooks, notebook-type personal computers, etc., in which an additional backlight is provided in the switch key area so as to facilitate the key operation even in the dark are known.
For example, in a portable telephone, a thin EL device is disposed as the backlight source in the side of the back surface of a switch key board. Through-holes are provided in the site of the EL device that correspond to switch keys. In this construction, when a switch key is pressed at its front surface, it is electrically connected with the EL device through the through-hole, and after the pressure is released, the electric connection is cut off. In this manner, the switch keys are lighted through light emission around the through-holes, allowing the keys to be differentiated even in the dark.
Ordinary EL devices emit light in the electric field of an alternating current, and generate electromagnetic noise. Therefore, electronic appliances equipped with an EL-combined sheet switch will often malfunction because of the electromagnetic noise generated by the EL device.
SUMMARY OF THE INVENTION
To solve the problems noted above, the EL-combined sheet switch of the present invention comprises a shield layer between the contact sheet and the EL sheet, in which the electromagnetic noise from the EL sheet is shielded by the shield layer to prevent the malfunction of the sheet switch. In the EL-combined sheet switch, the contact sheet is provided with a counter electrode that faces the switch pattern formed on the circuit board, and the counter electrode is capable of being detachably contacted with the switch pattern. The switching operation is therefore achieved through the contact and release of the switch pattern and the counter electrode that faces it. In the EL-combined sheet switch of the invention, the shield layer as provided between the contact sheet and the EL sheet shields the contact sheet from the electromagnetic waves running from the EL device. As a result, the electronic appliances equipped with the EL-combined sheet switch are prevented from malfunctioning.
Preferably, the shield layer is connected with the ground electrode formed on the circuit board.
REFERENCES:
patent: 4786767 (1988-11-01), Kuhlman
patent: 5149923 (1992-09-01), Demeo
patent: 5315204 (1994-05-01), Park
patent: 5399823 (1995-03-01), McCusker
patent: 5557079 (1996-09-01), Jackson et al.
patent: 5661279 (1997-08-01), Kenmochi
patent: 5664667 (1997-09-01), Kenmochi
patent: 5669486 (1997-09-01), Shima
patent: 5781088 (1999-02-01), Tanabe
patent: 5844166 (1998-12-01), Halttunen et al.
patent: 5924555 (1999-07-01), Sadmori et al.
patent: 2307105 (1997-05-01), None
Hirose Koji
Yamazaki Hiroshi
Amster Rothstein & Ebenstein
Donovan Lincoln
Nguyen Nhung
Seiko Precision Inc.
LandOfFree
EL-combined sheet switch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with EL-combined sheet switch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and EL-combined sheet switch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2525785