CONTACT DETECTION DEVICE, APPARATUS USING SUCH A DEVICE AND RADIOTELEPHONE COMPRISING SUCH AN APPARATUS

• US 20010040556A1
• Filed: 03/08/1999
• Published: 11/15/2001
• Est. Priority Date: 03/13/1998
• Status: Active Grant

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: BOIREAU, OLIVIER, ALIX, PHILIPPE
• Granted Patent: US 6,369,801 B2
• Time in Patent Office: Days
• US Class Current: 345/168
• 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 2219/018 Electroluminescent panel
• CPC Class Codes: H01H 2229/038 Folding of flexible printed circuit

Abstract

The device integrates, on a synthetic material foil, a system for detecting the action of keys of a keyboard and a homogeneous illumination system for the keyboard. A film 10 is folded into two parts 11 and 12. Domes 13 are preformed on the upper part 11 and a detection circuit 16 is printed on the lower part 12. Contact electrodes 15 are fixed under each dome 13 so as to realize an electric contact with the detection circuit 16 when the dome 13 is pressed by means of a key 22 of the keyboard 20. The keys of the keyboard are illuminated by an electroluminescent ink 17 between the domes 13, deposited on a plane surface 18 of the upper part 11 of the synthetic material foil 10.

Claims

1. A contact detection device comprising:

a first insulating film (11) constituting at least a dome (13) having an internal surface (13b), on which a contact electrode layer (15) is deposited, and an external surface (13a), and

a second insulating film (12) supporting a detection circuit (16) for detecting an electric contact between the contact electrode layer (15) and the detection circuit (16),

characterized in that a layer (17) of electroluminescent material is directly applied on the first film (11), on a plane surface (18) surrounding said external surface (13a).

2. A detection device as claimed in

claim 1

, characterized in that said first and second insulating films (11;

12) are constituted by a folded foil (10) of synthetic material, with said contact electrode (15) facing said detection circuit (16).

3. A detection device as claimed in

claim 2

, characterized in that a pressure on said external surface (13a) causes a plastic deformation of said dome (13) so as to realize an electric contact between said contact electrode layer (15) and said detection circuit (16).

4. A data communication apparatus comprising a keyboard (20;

22) and a detection device as claimed in any one of

claims 1

to

3

, characterized in that each key (20) is associated with a dome (13) for exerting a pressure force on said external surface (13a).

5. An apparatus as claimed in

claim 4

, comprising a liquid crystal display screen (33), characterized in that said plane surface (18) surrounding the external surface (13a) extends under the liquid crystal display screen (33).

6. A radiotelephone comprising an apparatus as claimed in

claim 4

or

5

, characterized in that said keyboard (20;

22) comprises parts of a translucent material proximate to the keys (22) so as to be illuminated by said layer (17) of electroluminescent material.