CA2014651A1 - Long traveling button switch with enhanced user feedback - Google Patents

Long traveling button switch with enhanced user feedback

Info

Publication number
CA2014651A1
CA2014651A1 CA 2014651 CA2014651A CA2014651A1 CA 2014651 A1 CA2014651 A1 CA 2014651A1 CA 2014651 CA2014651 CA 2014651 CA 2014651 A CA2014651 A CA 2014651A CA 2014651 A1 CA2014651 A1 CA 2014651A1
Authority
CA
Canada
Prior art keywords
keycap
plunger
switch
downward displacement
elastomeric
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.)
Abandoned
Application number
CA 2014651
Other languages
French (fr)
Inventor
Christopher K. Schroeder
Curt N. Torgerson
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.)
HP Inc
Original Assignee
Hewlett Packard Co
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 Hewlett Packard Co filed Critical Hewlett Packard Co
Publication of CA2014651A1 publication Critical patent/CA2014651A1/en
Abandoned legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/70Switches 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
    • H01H13/702Switches 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
    • H01H13/705Switches 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
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2215/00Tactile feedback
    • H01H2215/004Collapsible dome or bubble
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2215/00Tactile feedback
    • H01H2215/03Sound
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2221/00Actuators
    • H01H2221/064Limitation of actuating pressure

Landscapes

  • Push-Button Switches (AREA)

Abstract

LONG TRAVELLING BUTTON SWITCH
WITH ENCHANCED USER FEEDBACK

ABSTRACT OF THE DISCLOSURE

A pushbutton switch including a keycap having a keycap top and a keycap plunger, a retaining bezel for guiding the keycap plunger and limiting the displacement thereof, a deformable elastomeric switch button supporting a contact pad, and a printed circuit contact pattern engageable by the contact pad when the switch button is deformed by the downward displacement of the keycap plunger. The deformation of the button switch tactile feedback, while impact of the keycap top against the retaining bezel provides audible feedback. The pushbutton switch is configured to limit the downward displacement of the keycap plunger to avoid excessive force on the printed circuit board.

Description

201~6~1 :`
LONG TRAVELING BUTTON SWITCH
WITH ENCHANCED USER FEEDBACX

`; 1 BACKGROUND OF THE INVENTION

The disclosed invention is directed generally to a keyboard pushbutton switch, and more specifically is directed to a keyboard pushbutton switch having a long travel, and enhanced tactile and audible feedback, and improved contact reliability.
Pushbutton switches are utilized in keyboards for calculators, device control panels, and the like. A known pushbutton switch structure includes a dome-shaped metal-lic contact which contactively engages contacts on aprinted circuit board when deformed by actuation of an associated keycap. The deformation of the metallic dome provides both tactile feedback and audible feedback.
An important consideration with a pushbutton switch having a metallic dome contact is the relatively small contact area provided by the deformed dome, which makes such switches susceptible to non-closure due to dust and dirt contamination. In order to increase reliability, some metallic dome pushbutton switches are individually packaged for insertion in printed circuit boards. Such switches can be more expensive and bulkier.
Another consideration with metallic dome pushbutton switches i'3 transmission of the keypress force to the ~5 printed circuit board, which if excessive could cause damage.

. . ~ , - ~ , . .

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. 20~46~1 ,~ 2 1 A further consideration with pushbutton switches having metallic dome contacts is a limitation on the amount of key travel imposed by the metallic dome.
Relatively longer key travel provides for a more comfort-able keypress.

SUMMARY OF THE INVENTION
,., It would therefore be an advantage to provide a keyboard pushbutton switch structure having a reliably large contact area.
Another advantage would be to provide a keyboard pushbutton switch structure which reduces the amount of keypress force transmitted to the printed circuit board utilized therewith.
A further advantage would be to provide a keyboard pushbutton switch structure provides which p~ovides for sufficient key travel.
The foregoing and other advantages are provided by the invention in a pushbutton switch structure that includes a manually depressable keycap having a keycap top and a keycap plunger, a resiliently deformable elastomeric ,` switch button aligned with and engageable by the keycap plunger, a contact pattern supported on a printed circuit board located beneath the switch button, a contact element supported by the deformable switch button for contacting the contact pattern pursuant to deformation of the deform-able switch button by downward displacement of the keycap plunger, and a retaining bezel for guiding and limiting ~ 30 the displacement of the keycap plunger. The deformation ; of the button switch tactile feedback, while impact of the i; keycap top against the retaining bezel provides audible feedback.

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~, ., , ' 2~6~1 1BRIEF DESCRIPTION ~F THE DRAWING

The advantages and features o~ the disclosed inven-` tion will readily be appreciated by persons skilled in the 5art from the following detailed description when read in conjunction with the drawing wherein:
FIG. 1 is a schematic exploded perspective illus-tration of a pushbutton switch in accordance with the invention.
10FIG~ 2 is an elevational sectional view illustrating the pushbutton switch of FIGo 1 with the keycap plunger in the non-actuated position and exerting a slight preload on the switch dome.
FIG~ 3 is an elevational sectional view illustrating 15the pushbutton switch of FIG~ 1 with the keycap plunger ; sufficiently displaced to cause deformation of the switch dome and contactive closure of the switching elements.
FIG~ 4 is an elevational sectional view illustrating the pushbutton switch of FIG~ 1 with the keycap plunger 20sufficiently displaced to cause audible feedback from the impact of the keycap top on the retaining bezel.
, .
DETAILED DESCRIPTION OF THE DISCLOSURE

25In the following detailed description and in the several figures of the drawing, like elements are iden-tified with like reference numerals.
Referring now to FIG. 1 J shown therein is a push-button switch assembly that includes a keycap 11 having a 30keycap top lla and a keycap plunger llb. The keycap plunger lla is slidably engaged and retained in a guiding and retaining bezel 13 which, for example, is integrally formed with other bezels in a bezel structure 15. By way of example, the keycap plunger includes barb-like tabs for :

. .' : ., :

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;
1 engaging the bottom portions of the bezel 13 to limit the upward displacement of the keycap.
` An elastomeric dome switch button 17 is located beneath the keycap 11. By way of example, the switch button 17 is integrally formed in an elastomeric sheet 19, comprising rubber, for example, with other switch buttons.
The elastomeric sheet 19 rests on a printed circuit board - 21 ha~ing a conductive pattern 23 aligned with the switch button 17. By way of example, the conductive pattern 23 can comprise interleaved conductive traces to provide redundant contact elements. The printed circuit board 21 is attached to the bezel structure 15 to prevent relative displacement thereof.
The elastomeric dome switch button 17 comprises a conical side wall 17a secured to the ela~tomeric sheet 19 at its lower boundary. A horizontal top wall 17b is formed on the upper boundary of the conical side wall 17a, and a circular ridge 17c is formed on the top wall 17b. A
cylindrical bump 17d of shorter height than the circular ridge 17c is formed in the center of the top wall 17b.
The thicknesses of the top wall 17b, the circular ridge 17c, and the central bump 17d are greater than the thick-ness of the conical side wall so that the conical side wall resiliently deforms more easily than the thicker ' 25 elements.
- A conductive pad 25, comprising, for e~ample, a carbon impregnated elastomer, is attached to the underside of the top wall 17b generally in alignment with the bump 17c.
The keycap 11, the bezel 13, and the bezel structure 15 are configured to provide a slight preload on the switch button 17 when the keycap 11 is not actuated, as shown in FIG. 2. Further, the keycap 11 and bezel 13 are configured so that the bottom of the keycap top is against .

.
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2~1~6~1 l the top of the bezel 13 when the switch button 17 is fully deformed, which transfers further force to the bezel 13.
The pushbutton switch operates as follows. The user presses the top of the keycap top lla ~o displace the keycap 11 downwardly. The conical side wall 17a collapses just before the contact pad 25 engages the conductive pattern 23 on the printed circuit board, which causes a distinct variation in the resistance felt by the user '5 finger. In particular, the sudden collapse of the conical side wall 17a reduces the resistance on the keycap which, pursuant to the keypress force, then travels quickly to impact the bezel 13 and produce an audible feedback click.
FIG. 3 shows the contact pad 25 against the conductive pattern 23 just after the conical side wall has collapsed, and FIG. 4 shows the keycap at its downward travel limit against the bezel 13.
As particularly shown in FIG. ~, when the keycap 11 is fully depressed against the bezel 13, the side ~all 17a is collapsed, and the top wall 17b is slightly deformed around the contact pad 23, but does not touch the printed circuit board 19. Any keypress force applied to the keycap beyond that required to collapse the side wall 17a and deform the top wall as shown in FIG. 4 will be trans-mitted to the bezel 13 and not to the printed circuit board 19. In particular, the keycap 11, the bezel 13, and the switch button 17 are conrigured so that a limited amount of force is transmitted to the printed circuit board, for example, an amount determined to be sufficient to assure appropriate contact between the contact pad 25 and the conductive pattern 23. In this manner, contact is assured while preventing excessive forces on the printed circuit board 21.
The keycap travel and the nature of the tactile feedback are selected to provide for a comfortable ~: " . ,.
-2 ~ 5 ~

1 keypress that provides a distinct indication that contact has been made.
The keycap travel is determined by the difference between (a) the top to bottom height of the retaining bezel 13, and (b) the distance on the keycap plunger llb between the barb-like tabs and the underside of the keycap top lla. In conjunction with selection o~ keycap travel, the distance between the contact pad 23 and the printed circuit conductive pattern should be selected so that appropriate contact is assured while avoiding the applica-tion of excessive force when the ~eycap is fully de-pressed.
The nature of the tactile feedback, which is the force-to-displacement characteristic of the switch button 17, is determined by the thickness of the conical sidewall 17a, the thickness of the top wall 17b, the outside diameter of the top wall 17b, and the inside diameter of the lower boundary of the conical sidewall 17a.
The foregoing has been a disclosure of a pushbutton switch assembly that advantageously utilizes elastomeric switch buttons and provides tactile Eeedback as well as mechanically produced audible feedback. Further, the disclosed pushbutton switch allows for implementation of an appropriate comfortable keycap travel.
Although the foregoing has been a description and illustration of specific embodiments of the invention, various modifications and changes thereto can be made by persons skilled in the art without departing from the scope and spirit of the invention as defined by the following claims.

: ~'.,. -~ ,.. .

Claims (7)

1. A switch structure comprising:
a manually depressable keycap having a keycap top and a keycap plunger, said keycap being con-figured for upward and downward displacement;
resiliently deformable means engageable by said keycap plunger for yieldingly and deformably resist-ing downward displacement of said keycap plunger, said deformable means providing tactile feedback when deformed by the downward displacement of the keycap plunger;
first contact means supported on a substrate located beneath said keycap plunger;
second contact means supported by said deform-able means for contactively engaging said first contact means pursuant to deformation of said deformable means; and retaining means for guiding and limiting the downward displacement of said keycap plunger, and for providing audible feedback when said keycap has reached its downward displacement limit.
2. The switch structure of Claim 1 wherein said resiliently deformable means comprises an elastomeric switch button having a top that is engaged by said keycap plunger.
3. The switch structure of Claim 2 wherein said second contact means comprises a contact pad secured to the underside of the elastomeric dome.
4. The switch structure of Claim of Claim 3 wherein said second contact means comprises conductive traces on a printed circuit board.
5. The switch structure of Claim 4 wherein said retaining means comprises a retaining bezel which engages said keycap top to limit the downward displacement of said keycap plunger.
6. The switch structure of Claim 5 wherein said key cap, said retaining bezel, and said elastomeric switch button are configured to limit the downward displacement of said keycap plunger to avoid excessive force on the printed circuit board.
7. A pushbutton switch comprising:
a keycap having a keycap top and a keycap plunger configured for upward and downward displace-ment;
an elastomeric switch button engageable by downward displacement of said keycap plunger;
a conductive pattern supported on a printed circuit board beneath said elastomeric switch button;
a conductive pad on the underside of said elastomeric switch button for contactively engaging said conductive pattern pursuant to deformation of said elastomeric button switch; and a retaining bezel for guiding and limiting the downward displacement of said keycap plunger to provide audible feedback and to prevent excessive force on the printed circuit board.
CA 2014651 1989-09-27 1990-04-17 Long traveling button switch with enhanced user feedback Abandoned CA2014651A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US41303289A 1989-09-27 1989-09-27
US413,032 1989-09-27

Publications (1)

Publication Number Publication Date
CA2014651A1 true CA2014651A1 (en) 1991-03-27

Family

ID=23635521

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2014651 Abandoned CA2014651A1 (en) 1989-09-27 1990-04-17 Long traveling button switch with enhanced user feedback

Country Status (4)

Country Link
EP (1) EP0423924B1 (en)
JP (1) JPH0357837U (en)
CA (1) CA2014651A1 (en)
DE (1) DE69016569T2 (en)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4129234A1 (en) * 1991-09-03 1993-03-04 Bizerba Werke Kraut Kg Wilh KEYBOARD
DE9113199U1 (en) * 1991-10-23 1992-11-26 Cherry Mikroschalter Gmbh, 8572 Auerbach Key element with guide contour
EP0556426A1 (en) * 1992-02-19 1993-08-25 Acer Incorporated Keyboard switch assembly
JP3099165B2 (en) * 1993-06-28 2000-10-16 セイコーインスツルメンツ株式会社 Electronic device having switch mechanism and method of manufacturing substrate
DE19537144C2 (en) * 1995-10-05 1998-11-26 Siemens Nixdorf Inf Syst Single key
DE19631310A1 (en) * 1996-08-02 1998-02-05 Teves Gmbh Alfred Microswitch for mounting on to electronics circuit board
JPH10289631A (en) * 1997-04-14 1998-10-27 Alps Electric Co Ltd Pushbutton switch
JP3819124B2 (en) * 1997-08-29 2006-09-06 アルゼ株式会社 Switch structure
DE10203510C1 (en) * 2002-01-30 2003-02-20 Whirlpool Co Electric switch for operating/display panel has ratchet springs fixing switch operating element to seating provided by operating/display panel
JP5135738B2 (en) * 2006-08-30 2013-02-06 大日本印刷株式会社 Seed wrapping material and seed bag
US8404990B2 (en) 2010-06-30 2013-03-26 3M Innovative Properties Company Switch system having a button travel limit feature

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3668356A (en) * 1971-01-04 1972-06-06 Ibm Mechanical key actuator including a cantilever beam restoring force means
DE8105649U1 (en) * 1981-02-27 1981-08-13 Siemens AG, 1000 Berlin und 8000 München Keypad for telephones
US4496803A (en) * 1983-05-04 1985-01-29 Key Concepts, Incorporated Data entry switch
DE8401137U1 (en) * 1984-01-17 1984-05-03 Deutsche Fernsprecher Gesellschaft Mbh Marburg, 3550 Marburg Key, in particular for keypad keypads on telephones

Also Published As

Publication number Publication date
EP0423924A1 (en) 1991-04-24
DE69016569D1 (en) 1995-03-16
EP0423924B1 (en) 1995-02-01
DE69016569T2 (en) 1995-05-24
JPH0357837U (en) 1991-06-04

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Legal Events

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