GB2250380A - Switch apparatus - Google Patents
Switch apparatus Download PDFInfo
- Publication number
- GB2250380A GB2250380A GB9025704A GB9025704A GB2250380A GB 2250380 A GB2250380 A GB 2250380A GB 9025704 A GB9025704 A GB 9025704A GB 9025704 A GB9025704 A GB 9025704A GB 2250380 A GB2250380 A GB 2250380A
- Authority
- GB
- United Kingdom
- Prior art keywords
- flexible member
- switch apparatus
- switch
- thick film
- keyboard
- 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
Links
- 239000012528 membrane Substances 0.000 claims abstract description 12
- 239000000758 substrate Substances 0.000 claims abstract description 11
- 229910052751 metal Inorganic materials 0.000 claims abstract description 6
- 239000002184 metal Substances 0.000 claims abstract description 6
- 239000002131 composite material Substances 0.000 claims description 21
- 230000002093 peripheral effect Effects 0.000 claims description 10
- 238000007789 sealing Methods 0.000 claims description 8
- 239000011810 insulating material Substances 0.000 claims description 2
- 125000006850 spacer group Chemical group 0.000 claims description 2
- 239000010410 layer Substances 0.000 description 33
- 239000004020 conductor Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 229920003023 plastic Polymers 0.000 description 4
- 239000004033 plastic Substances 0.000 description 4
- 239000011241 protective layer Substances 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 239000000356 contaminant Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 101000793686 Homo sapiens Azurocidin Proteins 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000032798 delamination Effects 0.000 description 1
- 230000000881 depressing effect Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 229920002457 flexible plastic Polymers 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000976 ink Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 230000011664 signaling Effects 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
- H05K1/05—Insulated conductive substrates, e.g. insulated metal substrate
- H05K1/053—Insulated conductive substrates, e.g. insulated metal substrate the metal substrate being covered by an inorganic insulating layer
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2209/00—Layers
- H01H2209/01—Increasing rigidity; Anti-creep
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2209/00—Layers
- H01H2209/016—Protection layer, e.g. for legend, anti-scratch
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2209/00—Layers
- H01H2209/024—Properties of the substrate
- H01H2209/026—Properties of the substrate metallic
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2223/00—Casings
- H01H2223/002—Casings sealed
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2223/00—Casings
- H01H2223/01—Mounting on appliance
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2223/00—Casings
- H01H2223/046—Casings convertible
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2223/00—Casings
- H01H2223/06—Casings freestanding
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2229/00—Manufacturing
- H01H2229/024—Packing between substrate and membrane
- H01H2229/028—Adhesive
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2239/00—Miscellaneous
- H01H2239/004—High frequency adaptation or shielding
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2239/00—Miscellaneous
- H01H2239/01—Miscellaneous combined with other elements on the same substrate
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2239/00—Miscellaneous
- H01H2239/034—Environmental protection
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/09—Use of materials for the conductive, e.g. metallic pattern
- H05K1/092—Dispersed materials, e.g. conductive pastes or inks
- H05K1/095—Dispersed materials, e.g. conductive pastes or inks for polymer thick films, i.e. having a permanent organic polymeric binder
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/03—Metal processing
- H05K2203/0315—Oxidising metal
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/03—Metal processing
- H05K2203/0323—Working metal substrate or core, e.g. by etching, deforming
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Push-Button Switches (AREA)
Abstract
A switch apparatus for a keyboard 1 has an array of switch contacts 15, 16 provided by a thick film circuit 7 formed on a metal plate substrate. A spacing means 8 overlays the circuit and is in turn overlaid by a flexible membrane 9 having conductive pads 24 for making electrical contact with switch contacts 15 and 16. A gasket 27 of U-shaped cross-section provides a seal. Connection means 19 electrically connects the switch contacts 15, 16 to electronic circuitry 20 which generates an output signal representative of the contacts 15, 16 engaged by a selected conductive pad 24. <IMAGE>
Description
"SWITCH APPARATUS"
This invention relates to switch apparatus for a keyboard or keypad.
It is known to provide in a keyboard or keypad switch apparatus which is actuated by manually depressing key portions of a flexible member so as to move the flexible member into switching contact with switch contacts formed on a printed circuit board.
The flexible member may be a membrane which is spaced normally from the printed circuit board by a non-conductive layer as disclosed in GB-1537872 or may be shaped to include projections which normally maintain switch contacts in spaced relationship from the printed circuit board as disclosed in GB-2135827.
Such switch assemblies have an associated electronic circuit which generates an output signal representative of the selected key portion and which is housed separately from the switch apparatus and connected by suitable multi-conductor cabling.
It is necessary in many applications to totally exclude moisture and other contaminants from the switch assembly and electronic circuitry and typically both are enclosed in a sealed housing which adds significantly to the complexity of the overall assembly.
According to the present invention there is disclosed switch apparatus for a keyboard or keypad comprising an array of switch contacts formed on a support means, a flexible member overlaying the support means, spacing means normally maintaining the flexible member spaced from the support means, the flexible member having key portions selectively deformable into contact with corresponding switch contacts to provide electrical switching and the apparatus further comprising connecting means providing electrical connection between the switch contacts and electronic circuit means operable to generate an output signal representative of the selected key portion, wherein the support means comprises a thick film circuit formed on a substrate, the switch contacts comprise conductive surface portions of the thick film circuit and wherein the substrate comprises a metal plate.
An advantage of such an arrangement is that the metal plate provides screening against electromagnetic interference for the switch contacts, circuit means and the connecting means. The apparatus is also a freestanding assembly which can be used as a keyboard or keypad without necessarily being housed in a protective housing thereby reducing the complexity and cost of such apparatus.
Preferably the flexible member is a membrane of substantially uniform thickness and the spacing means comprises a spacing sheet of insulating material defining an array of apertures overlaid by corresponding key portions of the membrane.
Preferably the flexible member, the spacing sheet and the thick film circuit are bonded together to comprise a composite layer having a front face constituted by an outer surface of the flexible member and a rear face constituted by an outer surface of the substrate, the apparatus further comprising seal means extending in sealing contact between a peripheral portion of the front face and a peripheral portion of the rear face.
The apparatus is thereby rendered impervious to moisture and other contamination which might otherwise result in delamination of the composite layer or otherwise invade the adhesive bond between the thick film circuit, the spacing sheet and the flexible member.
Conveniently the seal means comprises a continuous gasket.
At least one edge portion of the composite layer may be provided with an edge member rigidly supporting the edge portion and defining a channel receiving the seal means.
The composite layer may thereby constitute a keyboard and comprise at least one foot member connected to the rear face of the composite layer and operable in use to space the keyboard from a supporting surface.
In a preferred embodiment the switch apparatus constitutes a keyboard for the input of alphanumeric data to an electronic processor and wherein the flexible member carries indicia which indicate the location of key portions and denote associated alphanumeric characters.
Conveniently the electronic circuit means comprises an exposed portion of the thick film circuit defined by an aperture in the spacer means and a corresponding aperture in the flexible member and further comprising cover means overlaying the electronic circuit means and making sealing contact with a continuous edge portion of the flexible member peripheral to the aperture.
An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings of which:
Figure 1 is a partially sectioned plan view of a keyboard;
Figure 2 is a front elevation of the keyboard of Figure 1;
Figure 3 is an end elevation of the keyboard of
Figures 1 and 2;
Figure 4 is a sectioned end elevation of part of the keyboard of Figures 1 to 3 showing detail of a supporting foot;
Figure 5 is a sectioned elevation of the keyboard of Figures 1 to 4 showing detail of a cover for the electronic circuit;
Figure 6 is a plan view of a modified end cap for use with the keyboard of Figures 1 to 5 and suitable for rack mounting applications;
Figure 7 is an end elevation of the end cap of
Figure 6; and
Figure 8 is a front elevation of the end cap of
Figures 6 and 7.
Figure 1 shows a keyboard 1 for the input of alpha numerical data to an electronic processor 2 via a cable 3. The keyboard 1 comprises a composite layer 4 having front and rear faces 5 and 6 respectively and consisting of a thick film circuit 7 overlaid by a spacing sheet 8 which in turn is overlaid by a flexible membrane 9.
The thick film circuit 7 is formed on a substrate comprising a stainless steel plate 10 as shown in Figure 4 having an outer surface 11 which constitutes the rear face 6 of the composite layer and an inner surface 12 upon which is deposited a dielectric layer 13 upon which the thick film circuit is printed.
The thick film circuit 7 includes an array of switch elements 14 each comprising first and second switch contacts 15 and 16 respectively comprising inter-digitated tracks of conductive material which are normally electrically isolated from one another. The thick film circuit 7 includes an encapsulating layer 17 having windows 18 corresponding to each switch element 14 so that switch contacts 15 and 16 remain exposed.
The switch contacts 15 and 16 are each connected via conductive tracks 19 formed on the dielectric layer 13 to an electronic circuit 20.
The spacing sheet 8 consists of a flexible insulating sheet of plastics material which is adhesively bonded to the encapsulating layer 17 and includes an array of apertures 21 which overlay and are in registration with the windows 18 to thereby expose the switch elements 14.
The flexible membrane 9 consists of a lower layer 22 of a flexible plastics material adhesively bonded to the spacing sheet 8 and an upper layer 23 adhesively bonded to the lower layer 22. The lower layer 22 is a transparent sheet having an array of electrically conductive pads 24 printed on the underside of the layer such that each of the switch elements 14 is overlaid by a respective conductive pad which is normally maintained in spaced relationship from the switch contacts 15 and 16 by the thickness of the surrounding spacing sheet 8.
The upper layer 23 is formed of an opaque plastics material having an array of indicia 25 marking the location of the conductive pads 24 and alpha numeric characters (not shown).
The indicia 25 identify to the user key portions 26 of the flexible membrane 9 which when manually depressed are deformable towards the plate 10 such that a selected key portion extends into its respective aperture 21 and its respective conductive pad 24 makes electrical contact with the first and second switch contacts 15 and 16 of the respective switch element 14.
As shown in Figure 4 the composite layer 4 is provided with a continuous gasket 27 of U-shaped cross-section which extends in sealing contact between a peripheral portion 28 of the front face and a peripheral portion 29 of the rear face 6. The composite layer 4 is thereby sealed against the ingress of moisture and contaminants which might otherwise invade the adhesive bond between the thick film circuit 7, the spacing sheet 8 and the membrane 9.
The keyboard 1 is rectangular in plan view having a front edge 30 approximately three times the length of lateral edges 31. A rear edge portion 36 of the composite layer 4 is received in a channel 33 defined by a rigid metal rear edge member 35 which also encloses the gasket 27 so as to compress the gasket into sealing contact with the composite layer.
A front edge member 34 adjacent the front edge 30 similarly encloses a front edge portion of the composite layer.
End caps 37 and 38 comprising mouldings of a plastics material similarly enclose lateral edge portions 39 and 40 of the composite layer 4 and compress the gasket 27 into sealing contact with the composite layer.
The spacing sheet 8 and the membrane 9 are provided with an aperture or cut-out 41 which allows surface mounted electrical components (not shown) of the electronic circuit 20 to project upwardly of the dielectric layer 13. The electronic circuit 20 is thereby confined within an exposed area of the thick film circuit 7 lying within the cut-out 41 and connected to the switch elements 14 by conductive tracks 19 of the thick film circuit.
A cover 42 overlays the cut-out 41 so as to enclose the electronic circuit 20 and is hermetically sealed to a continuous edge portion 43 of the membrane 9.
As seen in Figure 4 the keyboard 1 is provided at each end of the rear edge portion 36 with an extending foot 44 which is-pivotally mounted on a base 45 bonded to the rear face 6 of the composite layer 4.
As shown in Figure 5 a housing 46 is also bonded to the rear face 6 immediately beneath the electronic circuit 20 and provides a sealed outlet port 47 through which a signal cable 3 (not shown in
Figure 5) extends for connection to the electronic processor 2.
In Figures 6, 7 and 8 a modified end cap 50 is shown, the modified end cap being interchangeable with the end cap 37 of previous Figures. A complementary pair of such modified end caps are similarly adapted to enclose lateral edge portions 39 and 40 of the composite layer 4.
Modified end cap 50 includes a laterally projecting flange 51 including slots 52, 53 suitable for bolting the modified end cap to a rack. Rack mounting of the keyboard 1 in standard racks measuring 19 inches (0.4826 metres) is thereby facilitated by using such modified end caps.
The thick film circuit is formed on a suitable grade of stainless steel plate 10 having a chromium content of 17%. The steel plate 10 is subjected to a heat treatment in which the plate is passed through a multichamber temperature profiled oven at 8000C to 10000C. Migration of chromium takes place during this process in which oxidation forms a chromium oxide surface layer. Dielectric layers are then applied to the substrate, an initial adhesion layer being selected for high adhesion properties and having a coefficient of thermal expansion approximately equal to that of the steel.
One or more subsequent layers of graded coefficient are then applied such that a final layer has a coefficient matched to conventional thick film inks. Conductors, resistors and capacitors are then applied by conventional screen printing processes as required and surface mounted components such as transistors and integrated circuits are then soldered to conductors of the thick film circuit to provide a hybrid electronic circuit 20.
In the example described above with reference to Figures 1 to 8 the keyboard is suitable for use with a personal computer and the electronic circuit 20 is connected to the computer by a five conductor cable and communicates with the computer using a standard signalling protocol.
Switch apparatus in accordance with the present invention may be used in a variety of other applications including key pads for cash registers, control panels for machinery and key pads for telecommunications equipment.
The spacing means may be other than a spacing sheet having apertures and may for example comprise spacing formations projecting from the flexible member.
The substrate may include a protective layer covering the outer surface of the metal plate and constituting the outer surface of the substrate. In this case the seal means extends in sealing contact between the peripheral portion of the front face of the composite layer and a peripheral portion of the protective layer. The protective layer may for example be a film of plastics material.
Claims (10)
1. Switch apparatus for a keyboard or keypad comprising an array of switch contacts formed on a support means, a flexible member overlaying the support means, spacing means normally maintaining the flexible member spaced from the support means, the flexible member having key portions selectively deformable into contact with corresponding switch contacts to provide electrical switching and the apparatus further comprising connecting means providing electrical connection between the switch contacts and electronic circuit means operable to generate an output signal representative of the selected key portion, wherein the support means comprises a thick film circuit formed on a substrate, the switch contacts comprise conductive surface portions of the thick film circuit and wherein the substrate comprises a metal plate.
2. Switch apparatus as claimed in claim 1 wherein the flexible member is a membrane of substantially uniform thickness and the spacing means comprises a spacing sheet of insulating material defining an array of apertures overlaid by corresponding key portions of the membrane.
3. Switch apparatus as claimed in claim 2 wherein the flexible member, the spacing sheet and the thick film circuit are bonded together to comprise a composite layer having a front face constituted by an outer surface of the flexible member and a rear face constituted by an outer surface of the substrate, the apparatus further comprising seal means extending in sealing contact between a peripheral portion of the front face and a peripheral portion of the rear face.
4. Switch apparatus as claimed in claim 3 wherein the seal means comprises a continuous gasket.
5. Switch apparatus as claimed in any of claims 3 and 4 wherein at least one edge portion of the composite layer is provided with an edge member rigidly supporting the edge portion and defining a channel receiving the seal means.
6. Switch apparatus as claimed in any of claims 3 to 5 wherein the composite layer constitutes a keyboard and comprises at least one foot member connected to the rear face of the composite layer and operable in use to space the keyboard from a supporting surface.
7. Switch apparatus as claimed in any of claims 3 to 6 wherein the switch apparatus constitutes a keyboard for the input of alphanumeric data to an electronic processor and wherein the flexible member carries indicia which indicate the location of key portions and denote associated alphanumeric characters.
8. Switch apparatus as claimed in any preceding claim wherein the electronic circuit means comprises an exposed portion of the thick film circuit defined by an aperture in the spacer means and a corresponding aperture in the flexible member and further comprising cover means overlaying the electronic circuit means and making sealing contact with a continuous edge portion of the flexible member peripheral to the aperture.
9. Switch apparatus as claimed in any preceding claim wherein the connecting means comprises conductive surface tracks of the thick film circuit.
10. Switch apparatus substantially as hereinbefore described with reference to and as shown in any of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9025704A GB2250380B (en) | 1990-11-27 | 1990-11-27 | Switch apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9025704A GB2250380B (en) | 1990-11-27 | 1990-11-27 | Switch apparatus |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9025704D0 GB9025704D0 (en) | 1991-01-09 |
| GB2250380A true GB2250380A (en) | 1992-06-03 |
| GB2250380B GB2250380B (en) | 1995-01-04 |
Family
ID=10686013
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9025704A Expired - Fee Related GB2250380B (en) | 1990-11-27 | 1990-11-27 | Switch apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2250380B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2306783A (en) * | 1995-10-16 | 1997-05-07 | Gen Information Systems Ltd | Integrated circuit card reader |
| EP0671752A3 (en) * | 1994-03-11 | 1998-03-11 | Cherry Mikroschalter GmbH | Keyboard |
| DE4442073C2 (en) * | 1994-11-25 | 2001-10-18 | Cherry Mikroschalter Gmbh | Keyboard with metal plate |
| EP1807852B1 (en) * | 2004-11-02 | 2011-05-18 | Siemens Aktiengesellschaft | Monitoring method for a separation path of an electric switching device, which is defined by contact pieces which can be displaced in relation to each other, and associated device for carrying out said monitoring method |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2043352A (en) * | 1979-02-02 | 1980-10-01 | Northern Telecom Ltd | Pushbutton switch assembly for telecommunications and other input apparatus |
| US4228330A (en) * | 1978-07-10 | 1980-10-14 | Litton Systems, Inc. | Touch panel mechanism |
| EP0017580A1 (en) * | 1979-04-03 | 1980-10-15 | OREGA ELECTRONIQUE & MECANIQUE | Keyboard with luminous indicators, especially for a control box |
| US4367380A (en) * | 1980-08-27 | 1983-01-04 | Oak Industries Inc. | Keyboard assembly and components therefor |
| GB2132028A (en) * | 1982-12-03 | 1984-06-27 | Casio Computer Co Ltd | Sheet-like miniaturized electronic device |
| US4515999A (en) * | 1983-01-24 | 1985-05-07 | Rogers Corporation | Full travel keyboard |
| GB2156588A (en) * | 1984-03-28 | 1985-10-09 | Mektron France Sa | Membrane switch |
| GB2183401A (en) * | 1985-11-22 | 1987-06-03 | Morse Nena | Switch assembly |
-
1990
- 1990-11-27 GB GB9025704A patent/GB2250380B/en not_active Expired - Fee Related
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4228330A (en) * | 1978-07-10 | 1980-10-14 | Litton Systems, Inc. | Touch panel mechanism |
| GB2043352A (en) * | 1979-02-02 | 1980-10-01 | Northern Telecom Ltd | Pushbutton switch assembly for telecommunications and other input apparatus |
| EP0017580A1 (en) * | 1979-04-03 | 1980-10-15 | OREGA ELECTRONIQUE & MECANIQUE | Keyboard with luminous indicators, especially for a control box |
| US4367380A (en) * | 1980-08-27 | 1983-01-04 | Oak Industries Inc. | Keyboard assembly and components therefor |
| GB2132028A (en) * | 1982-12-03 | 1984-06-27 | Casio Computer Co Ltd | Sheet-like miniaturized electronic device |
| US4515999A (en) * | 1983-01-24 | 1985-05-07 | Rogers Corporation | Full travel keyboard |
| GB2156588A (en) * | 1984-03-28 | 1985-10-09 | Mektron France Sa | Membrane switch |
| GB2183401A (en) * | 1985-11-22 | 1987-06-03 | Morse Nena | Switch assembly |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0671752A3 (en) * | 1994-03-11 | 1998-03-11 | Cherry Mikroschalter GmbH | Keyboard |
| DE4442073C2 (en) * | 1994-11-25 | 2001-10-18 | Cherry Mikroschalter Gmbh | Keyboard with metal plate |
| GB2306783A (en) * | 1995-10-16 | 1997-05-07 | Gen Information Systems Ltd | Integrated circuit card reader |
| GB2306783B (en) * | 1995-10-16 | 1999-10-06 | Gen Information Systems Ltd | Integrated circuit card reader |
| EP1807852B1 (en) * | 2004-11-02 | 2011-05-18 | Siemens Aktiengesellschaft | Monitoring method for a separation path of an electric switching device, which is defined by contact pieces which can be displaced in relation to each other, and associated device for carrying out said monitoring method |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9025704D0 (en) | 1991-01-09 |
| GB2250380B (en) | 1995-01-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19950404 |