GB2291837A - Structure of key switch - Google Patents

Structure of key switch Download PDF

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Publication number
GB2291837A
GB2291837A GB9415173A GB9415173A GB2291837A GB 2291837 A GB2291837 A GB 2291837A GB 9415173 A GB9415173 A GB 9415173A GB 9415173 A GB9415173 A GB 9415173A GB 2291837 A GB2291837 A GB 2291837A
Authority
GB
United Kingdom
Prior art keywords
key body
key switch
designs
key
rubber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9415173A
Other versions
GB2291837B (en
GB9415173D0 (en
Inventor
Jason Tsai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Silitek Corp
Original Assignee
Silitek Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Silitek Corp filed Critical Silitek Corp
Priority to GB9415173A priority Critical patent/GB2291837B/en
Publication of GB9415173D0 publication Critical patent/GB9415173D0/en
Publication of GB2291837A publication Critical patent/GB2291837A/en
Application granted granted Critical
Publication of GB2291837B publication Critical patent/GB2291837B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
    • H01H13/702—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
    • H01H13/705—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches characterised by construction, mounting or arrangement of operating parts, e.g. push-buttons or keys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2219/00—Legends
    • H01H2219/054—Optical elements
    • H01H2219/066—Lens
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2221/00—Actuators
    • H01H2221/002—Actuators integral with membrane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2221/00—Actuators
    • H01H2221/002—Actuators integral with membrane
    • H01H2221/006—Adhesive

Landscapes

  • Push-Button Switches (AREA)

Abstract

A key switch which includes a rubber key body having designs on a top surface thereof, a thin, transparent layer of bonding medium covered over the top surface and designs of the rubber key body, and a lens of engineering plastics bonded to the layer of bonding medium and covered over the top surface of the key body to magnify the designs on the rubber key body. <IMAGE>

Description

STRUCTURE OF KEY SWITCH The present invention relates to key switches.
The key body of a key switch for an electronic instrument (mobile telephone, remote controller, etc.) may be moulded from rubber or plastics. A plastic key body must incorporate a spring or like means at the bottom so that it automatically returns to its former position after each press. However, the installation of a spring greatly increases the manufacturing cost of the key switch. Furthermore, the problem of elastic fatigue tends to occur after long periods of use if a key switch is made having a plastic key body and a spring at the bottom of the plastic key body.
A key switch having a rubber key body is less expensive and can allow the instrument to be made as thin as possible. However, the rubber key body may become covered with a layer of greasy dirt due to the frequent touch of the user's finger or face skin, causing the conductivity of the rubber key body to be affected. The rubber key body of a key switch is generally made with letters or designs for identification. The letters or designs will be rubbed away after long periods of use. Furthermore, in order to reduce the size of the instrument, the key switch must be made as small as possible. When a key switch is made very small, it is difficult to identify the letters or designs on the rubber key body.
This invention provides a key switch comprising a rubber key body having designs on a top surface thereof, a transparent layer of bonding medium covered over the top surface and designs of said rubber key body, and a lens of engineering plastics bonded to said layer of bonding medium and covered over the top surface of said key body to magnify the designs on said rubber key body.
Preferably the layer of bonding medium should be a thin layer.
Accordingly, embodiments of the present invention provide an improved structure of key switch which eliminates or at least alleviates the aforesaid drawbacks. Embodiments of the present invention provide a lens for a key switch which protects the rubber key body and magnifies the letters or designs on the rubber key body, and a bonding medium for a key switch which permits the lens of engineering plastics to be bonded to a rubber key body.
The invention will now be described by way of example with reference to the accompanying drawings, throughout which like parts are referred to by like references, and in which: Figure 1 is an exploded view of a preferred embodiment of the present invention; Figure 2 is a sectional elevation of the embodiment of Figure 1; Figure 3 is an elevational view of the embodiment of Figure 1; and Figure 4 shows a mobile telephone having key switches made according to an embodiment of the present invention.
Referring to Figures 1, 2 and 3, a key switch in accordance with the present invention is generally comprised of a key body 1 of moulded rubber having letters or designs on the top surface thereof, a transparent, thin layer of bonding medium 2 covered over the top surface of the key body 1 and a lens 3 bonded to the layer of bonding medium 2 and covered over the top surface of the key body 1 for protection. The lens 3 is made from liquid engineering plastics and directly moulded on the key body 1 over the layer of bonding medium 2, having a top surface curved upwards so that it magnifies the letters or designs on the key body 1 when viewed through the lens.
The aforesaid layer of bonding medium is made from resin of viscosity over about 4 Centipoise (0.004 Pascal second), before being cured or set. The aforesaid engineering plastics can be epoxy or acrylic resin of viscosity within the range of about 18000 to 25000 Centipoise (18 to 25 Pascal second), before being cured or set.
Furthermore, the optimum surface tension of the key body is within about 20 to 30 Dyne/cm (0.02 to 0.03 Newton/metre), before being cured or set. The amount of bonding of the engineering plastics varies with the shape of the key body. The surface tension and viscosity of the engineering plastics vary with the material used.
Referring to Figure 4, therein illustrated is a mobile telephone having key switches made according to an embodiment of the present invention. Of course, the present embodiment can be employed to make any of a variety of key switches for telephones, remote controllers, palm-top computers, etc.
In summary, embodiments of the invention provide a key switch which comprises a rubber key body and a lens of engineering plastics bonded to the rubber key body by a bonding medium to magnify the letters or designs on the rubber key body.
While only one embodiment of the present invention has been shown and described, it will be understood that various modifications and changes could be made without departing from the scope of the invention.

Claims (7)

1. A key switch comprising a rubber key body having designs on a top surface thereof, a transparent layer of bonding medium covered over the top surface and designs of said rubber key body, and a lens of engineering plastics bonded to said layer of bonding medium and covered over the top surface of said key body to magnify the designs on said rubber key body.
2. A key switch as claimed in claim 1 wherein said engineering plastics is epoxy resin.
3. A key switch as claimed in claim 1 wherein said engineering plastics is acrylic resin.
4. A key switch as claimed in any one of claims 1 to 3, wherein said engineering plastics has a viscosity of about 18000 to 25000 Centipoise.
5. A key switch as claimed in any one of the preceding claims, wherein said bonding medium is made from a resin of viscosity over about 4 Centipoise.
6. A key switch as claimed in any one of the preceding claims, wherein said rubber key body has surface tension of about 20 to 30 Dyne/cm.
7. A key switch substantially as hereinbefore described with reference to the accompanying drawings.
GB9415173A 1994-07-27 1994-07-27 Structure of key switch Expired - Fee Related GB2291837B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9415173A GB2291837B (en) 1994-07-27 1994-07-27 Structure of key switch

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9415173A GB2291837B (en) 1994-07-27 1994-07-27 Structure of key switch

Publications (3)

Publication Number Publication Date
GB9415173D0 GB9415173D0 (en) 1994-09-14
GB2291837A true GB2291837A (en) 1996-02-07
GB2291837B GB2291837B (en) 1998-03-04

Family

ID=10758978

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9415173A Expired - Fee Related GB2291837B (en) 1994-07-27 1994-07-27 Structure of key switch

Country Status (1)

Country Link
GB (1) GB2291837B (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2313343A (en) * 1996-05-20 1997-11-26 Reuters Ltd A keyboard having keycaps with transparent front faces
EP0896349A2 (en) * 1997-08-08 1999-02-10 Shin-Etsu Polymer Co., Ltd. Cover member for illuminated push button switch and method for manufacturing same
WO1999049486A1 (en) * 1998-03-25 1999-09-30 Linda Lee Cumings A keyboard
EP1391905A1 (en) * 2002-08-19 2004-02-25 Leica Geosystems AG Flat key pad
EP2075815A1 (en) * 2007-12-26 2009-07-01 HTC Corporation Key structure
US20120190409A1 (en) * 2006-09-25 2012-07-26 Research In Motion Limited Ramped-Key Keyboard for a Handheld Mobile Communication Device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4937408A (en) * 1988-05-30 1990-06-26 Mitsubishi Denki Kabushiki Kaisha Self-illuminating panel switch

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4937408A (en) * 1988-05-30 1990-06-26 Mitsubishi Denki Kabushiki Kaisha Self-illuminating panel switch

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2313343A (en) * 1996-05-20 1997-11-26 Reuters Ltd A keyboard having keycaps with transparent front faces
EP0896349A2 (en) * 1997-08-08 1999-02-10 Shin-Etsu Polymer Co., Ltd. Cover member for illuminated push button switch and method for manufacturing same
EP0896349A3 (en) * 1997-08-08 1999-08-25 Shin-Etsu Polymer Co., Ltd. Cover member for illuminated push button switch and method for manufacturing same
US6413598B1 (en) 1997-08-08 2002-07-02 Shin-Etsu Polymer Co., Ltd. Cover member for illuminated push button switch and method for manufacturing same
WO1999049486A1 (en) * 1998-03-25 1999-09-30 Linda Lee Cumings A keyboard
EP1391905A1 (en) * 2002-08-19 2004-02-25 Leica Geosystems AG Flat key pad
US20120190409A1 (en) * 2006-09-25 2012-07-26 Research In Motion Limited Ramped-Key Keyboard for a Handheld Mobile Communication Device
US8449208B2 (en) * 2006-09-25 2013-05-28 Research In Motion Limited Ramped-key keyboard for a handheld mobile communication device
EP2075815A1 (en) * 2007-12-26 2009-07-01 HTC Corporation Key structure
US8049125B2 (en) 2007-12-26 2011-11-01 Htc Corporation Key structure
TWI400735B (en) * 2007-12-26 2013-07-01 Htc Corp Key structure

Also Published As

Publication number Publication date
GB2291837B (en) 1998-03-04
GB9415173D0 (en) 1994-09-14

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19990727