CA2282446A1 - Electrostatic discharge protection in a portable communication device - Google Patents
Electrostatic discharge protection in a portable communication device Download PDFInfo
- Publication number
- CA2282446A1 CA2282446A1 CA002282446A CA2282446A CA2282446A1 CA 2282446 A1 CA2282446 A1 CA 2282446A1 CA 002282446 A CA002282446 A CA 002282446A CA 2282446 A CA2282446 A CA 2282446A CA 2282446 A1 CA2282446 A1 CA 2282446A1
- Authority
- CA
- Canada
- Prior art keywords
- circuit board
- keypad
- domefoil
- communication device
- esd
- 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
Links
- 230000006854 communication Effects 0.000 title claims abstract description 25
- 238000004891 communication Methods 0.000 title claims abstract description 25
- 230000000994 depressogenic effect Effects 0.000 claims abstract description 4
- 230000001413 cellular effect Effects 0.000 claims description 9
- 238000005286 illumination Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 claims 1
- 230000006870 function Effects 0.000 abstract description 3
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 208000032365 Electromagnetic interference Diseases 0.000 description 1
- 239000000872 buffer Substances 0.000 description 1
- 150000001722 carbon compounds Chemical class 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000000881 depressing effect Effects 0.000 description 1
- 238000010892 electric spark Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 230000036039 immunity Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012811 non-conductive material Substances 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 229940100890 silver compound Drugs 0.000 description 1
- 150000003379 silver compounds Chemical class 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/02—Constructional features of telephone sets
- H04M1/0202—Portable telephone sets, e.g. cordless phones, mobile phones or bar type handsets
-
- 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
-
- 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
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/02—Constructional features of telephone sets
- H04M1/23—Construction or mounting of dials or of equivalent devices; Means for facilitating the use thereof
-
- 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
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0067—Devices for protecting against damage from electrostatic discharge
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2215/00—Tactile feedback
- H01H2215/004—Collapsible dome or bubble
- H01H2215/008—Part of substrate or membrane
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2231/00—Applications
- H01H2231/022—Telephone handset
-
- 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
- H01H2239/008—Static electricity considerations
Abstract
A portable communication device (10) has an electronic circuit board (20) arranged inside a housing (12), and a keypad (30), the individual keys (32) of which are arranged, when depressed, to collapse a respective tactile dome (52) on a domefoil (50) interposed between the keypad and the circuit board, so as to establish electric contact with a respective contact point (22) on the circuit board. The communication device has means for protecting the circuit board from electrostatic discharge (ESD). The domefoil (50) is formed as a non-conductive sheet providing an air-tight and/or electrostatic seal between the keypad (30) and the circuit board (20), whereby the domefoil functions as said ESD-protective means.
Description
ELECTROSTATIC DISCHARGE PROTECTION IN A PORTABLE COI~lUNI-' CATTON DEVICE
Technical Field The present invention relates to a portable communi-cation device, comprising an electronic circuit board arranged inside a housing, and a keypad, the individual keys of which are arranged, when depressed, to collapse a respective tactile dome on a domefoil interposed between the keypad and the circuit board, so as to establish elec-tric contact with a respective contact point on the circuit board, said communication device being provided with means for protecting the circuit board from electrostatic dis-charge (ESD).
Description of the Prior Art Portable communication devices are used in various applications to provide a means for remote communication between two parties. Common communication devices of this kind are for instance cellular telephones, cordless phones, paging devices, walkie-talkies, PDAs (Personal Digital Assistants), etc. Such devices comprise an apparatus housing, in which an electronic circuit board is arranged.
The circuit board is provided with circuitry necessary for performing the operational communication tasks of the device, e.g. CPU, memory modules and radio circuits (ampli-fiers, local oscillators, filters, modulators, mixers, etc). Furthermore, the circuit board is often provided with LEDs (Light Emitting Diodes) or other devices for illumina-3o ting a keypad arranged in the housing.
Keypad-operated devices of the kind described above have to fulfil various requirements in order to provide a reliable communication service to the user of the device.
Such requirements are for instance immunity to electrosta-tic discharge (ESD) as well as a sufficiently high degree of electromagnetic compatibility (EMC). When the user touches the keypad, there is an apparent risk of an electrostatic discharge between the user's fingertip and conductive elements, e.g. the electronic circuit board inside the device, and hence a keypad-operated communi-S cation device must be provided with ESD-protective means.
Furthermore, the device must be shielded in a way that prevents the active parts of the communication device from interfering electromagnetically with surrounding electronic equipment. Such shielding must also protect the device from electromagnetic influences or disturbances caused by such surrounding electronic equipment.
Summary of the Invention It is an object of the present invention to provide a portable communication device with safe and inexpensive electrostatic discharge protection. A further object of some embodiments is to provide the communication device with means protecting the device from electrostatic dis-charge (ESD) as well as assuring electromagnetic compatibi-lity (EMC) .
The objects of the invention are achieved for a portable communication device of the kind described above by protecting the circuit board inside the communication device from electrostatic discharge by means of a domefoil formed as a non-conductive sheet providing an air-tight and/or electrostatic seal between the keypad and the cir-cuit board.
Brief Description of the Drawings Preferred embodiments of the invention will be described in more detail in the following, reference being made to the accompanying drawings, in which:
FIG 1 is a schematic view of an exemplary cellular telephone, for which the invention may be applied, Y, , ,.,, WO 98139785 3 PCTlSE98100208 FIG 2 is a schematic perspective view of a prior art keypad arrangement in a cellular telephone, and FIG 3 is a schematic perspective view of a combined keypad and ESD-protective arrangement according to a preferred embodiment of the invention.
Description of Preferred Embodiments In FIG 1 there is shown an exemplary cellular tele-phone 10, comprising an apparatus housing 12, an antenna 13, a loudspeaker 14, a display 15, and a microphone 16.
Furthermore, the cellular telephone 10 is provided with a keypad 30 for user communication. A user controls the operation of the cellular telephone by entering commands on the keypad 30, i.e. by depressing an appropriate individual key 32 among the set of keys in the keypad 30. Preferably, the keypad comprises a set of alphanumeric keys labelled "0" through "9", as well as control keys such as "*" and "#", an "Answer" or "YES" key, a "Hangup" or "NO" key, volume control keys, etc. From an overall point of view according to FIG 1 the cellular telephone 10 is well-known in all relevant aspects to a man skilled in the art, and hence no further description is made here.
FIG 2 discloses a previously known keypad arrangement for a cellular telephone. A keypad 30 is made from e.g.
rubber and comprises a set of individual keys 32. Although not shown in the drawing each key 32 is labelled according to its dedicated purpose, for instance a digit "3" or a "*"
sign. A domefoil 40 made from plastics or the like is interposed between the keypad 30 and an electronic circuit ' 30 board 20 arranged inside the telephone housing. The dome-foil 40 is provided with a plurality of tactile domes 42, ' each of which is given a convex shape protruding or bulging from the domefoil 40. One respective dome 42 is arranged beneath one respective key 32 in the keypad 30.
The circuit board 20 is given a purely schematical appearance in FIG 2. The circuit board 20 comprises various electronic circuitry, such as radio transmitter/receiver circuits, amplifiers, filters, buffers, oscillators, mixers, one or several micro-processors, memory modules, etc., none of which are indicated in FIG 2. Furthermore, the circuit board 20 is provided with a set of contact points 22, a respective one of which being arranged in vertical alignment with a respective pair of key 32 and dome 42.
The functional operation of the keypad 30 is as follows. When a key 32 is depressed by a user, the back of the key will excert a force upon the underlying tactile dome 42. The dome 42 will not be able to resist the force excerted by the key 32 but will collapse inwardly/down-wardly and reach contact with the underlying contact point 22. For this purpose the rear side of each dome 42 is made electrically conductive, for instance by providing each dome with a conductive layer, such as a silver or carbon compound. The collapsing dome establishes electric contact between a contact pair at the contact point 22, the details of which are omitted in the drawing, since they are believed to be well-known per se to a man skilled in the art. The electric connection so established is immediately detected by a controller comprised on the circuit board.
Furthermore, the circuit board 20 is provided with illuminating means 24 realized as LEDs (Light Emitting Diodes), the purpose of which is to illuminate the keys 32 through respective openings 44 in the domefoil 40. In FIG 2 one illuminating means 24 is arranged to illuminate four keys 32 surrounding the opening 44. In addition to these openings the domefoil 40 is provided with various holes, openings or recesses 46, 48, 49 for various electronic components or mounting means arranged on the circuit board 2 0 .
, . . ... ..,.. , In the prior art arrangement according to FIG 2 the rubber-based keypad sheet 32 serves as an ESD-protective means. Furthermore, the housing 12 shown in FIG 1 is pro-vided on the inside thereof with a thin metallized layer funtioning as a protection or a shielding against electro-magnetic interference between the telephone 10 and sur-rounding electronic equipment. Although providing a suffi-cient protection against ESD as well as electromagnetic interference, the prior art arrangement according to FIG 2 is disadvantageous when it comes to cost considerations.
Both the keypad rubber sheet 30 and the metallized layer inside the housing 10 add a non-negligable price penalty to the total cost for manufacturing the telephone 10.
The inventive solution according to FIG 3 proposes a less expensive way of providing the telephone with means for protection against ESD. According to the present inven-tion the domefoil 50, with its set of tactile key domes 52, is formed as a sheet fully covering the entire surface be-tween the keypad 30 and the underlying circuit board 20. At least the front surface of the domefoil 50 is made electri-cally non-conductive or isolating, thereby providing an air-tight and/or electrostatic seal between the keypad and the circuit board and thus functioning as an ESD-protective means. In contrast to the prior art domefoil 40 in FIG 2, the inventive domefoil 50 has no open-air openings which would permit an electric spark to be transferred from a key 32 to the circuit board 20. All previous openings, such as the openings for the illuminating means 24, are covered with additional domes 54 of a non-conductive material isolating the circuit board 20 from the keypad 30.
According to the preferred embodiment in FIG 3 the keypad 30 is realized as a keytree made from plastics or the like. Such a keytree structure is previously known per se to be a very cheap way of realizing a keypad function in a communication device. Thanks to the integrated domefoil 50 there is no longer any need for the keypad 30 to be made from rubber or having to act as ESD-protection as well as a means for user interaction.
As mentioned above the domefoil 50 is provided with.
additional domes 54 for the underlying illuminating means 24 (which are realized as LEDs or similar components).
Obviously the additional domes 54 must be made transparent or at least semi-transparent to the light emitted from the illuminating means 24. Preferably the additional domes 54 are made white or glossy so as to give a better illumina-tion of the keypad 30. In an alternative embodiment the additional domes 54 could be printed with a certain screen or dot pattern to direct the light towards the four keys 32 surrounding the dome 54 and the underlying illuminating means 24. This pattern may exhibit lines or dots which are arranged at increasing size or density in the directions of the keys 32.
According to one embodiment of the invention the interior of the domefoil 50 is provided with a layer of electrically conductive material, such as a silver com-pound. The conductive layer is connected to a grounding means so as to function as a means for protection against electromagnetic interference, thereby assuring electro-magnetic compatibility. Hence, the need for a metallized apparatus housing in the prior art arrangement according to FTG 2 has been eliminated, and the domefoil will act as a combined means for protection against ESD as well as electromagnetic interference.
To help dissipating heat generated by the various circuits and components on the electronic circuit board 20 the domefoil 50 may be provided with air channels extending along a major part of the domefoil and reaching some of the edges of the domefoil 50.
The present invention has been described above with reference to a few embodiments or examples, but it is to be ..
WO 98139785 ~ PCTlSE98100208 understood that the invention shall by no means be restric-ted to the specific embodiments disclosed in the foregoing.
On the contrary, the present invention shall only be limited by the scope of the appended patent claims.
Technical Field The present invention relates to a portable communi-cation device, comprising an electronic circuit board arranged inside a housing, and a keypad, the individual keys of which are arranged, when depressed, to collapse a respective tactile dome on a domefoil interposed between the keypad and the circuit board, so as to establish elec-tric contact with a respective contact point on the circuit board, said communication device being provided with means for protecting the circuit board from electrostatic dis-charge (ESD).
Description of the Prior Art Portable communication devices are used in various applications to provide a means for remote communication between two parties. Common communication devices of this kind are for instance cellular telephones, cordless phones, paging devices, walkie-talkies, PDAs (Personal Digital Assistants), etc. Such devices comprise an apparatus housing, in which an electronic circuit board is arranged.
The circuit board is provided with circuitry necessary for performing the operational communication tasks of the device, e.g. CPU, memory modules and radio circuits (ampli-fiers, local oscillators, filters, modulators, mixers, etc). Furthermore, the circuit board is often provided with LEDs (Light Emitting Diodes) or other devices for illumina-3o ting a keypad arranged in the housing.
Keypad-operated devices of the kind described above have to fulfil various requirements in order to provide a reliable communication service to the user of the device.
Such requirements are for instance immunity to electrosta-tic discharge (ESD) as well as a sufficiently high degree of electromagnetic compatibility (EMC). When the user touches the keypad, there is an apparent risk of an electrostatic discharge between the user's fingertip and conductive elements, e.g. the electronic circuit board inside the device, and hence a keypad-operated communi-S cation device must be provided with ESD-protective means.
Furthermore, the device must be shielded in a way that prevents the active parts of the communication device from interfering electromagnetically with surrounding electronic equipment. Such shielding must also protect the device from electromagnetic influences or disturbances caused by such surrounding electronic equipment.
Summary of the Invention It is an object of the present invention to provide a portable communication device with safe and inexpensive electrostatic discharge protection. A further object of some embodiments is to provide the communication device with means protecting the device from electrostatic dis-charge (ESD) as well as assuring electromagnetic compatibi-lity (EMC) .
The objects of the invention are achieved for a portable communication device of the kind described above by protecting the circuit board inside the communication device from electrostatic discharge by means of a domefoil formed as a non-conductive sheet providing an air-tight and/or electrostatic seal between the keypad and the cir-cuit board.
Brief Description of the Drawings Preferred embodiments of the invention will be described in more detail in the following, reference being made to the accompanying drawings, in which:
FIG 1 is a schematic view of an exemplary cellular telephone, for which the invention may be applied, Y, , ,.,, WO 98139785 3 PCTlSE98100208 FIG 2 is a schematic perspective view of a prior art keypad arrangement in a cellular telephone, and FIG 3 is a schematic perspective view of a combined keypad and ESD-protective arrangement according to a preferred embodiment of the invention.
Description of Preferred Embodiments In FIG 1 there is shown an exemplary cellular tele-phone 10, comprising an apparatus housing 12, an antenna 13, a loudspeaker 14, a display 15, and a microphone 16.
Furthermore, the cellular telephone 10 is provided with a keypad 30 for user communication. A user controls the operation of the cellular telephone by entering commands on the keypad 30, i.e. by depressing an appropriate individual key 32 among the set of keys in the keypad 30. Preferably, the keypad comprises a set of alphanumeric keys labelled "0" through "9", as well as control keys such as "*" and "#", an "Answer" or "YES" key, a "Hangup" or "NO" key, volume control keys, etc. From an overall point of view according to FIG 1 the cellular telephone 10 is well-known in all relevant aspects to a man skilled in the art, and hence no further description is made here.
FIG 2 discloses a previously known keypad arrangement for a cellular telephone. A keypad 30 is made from e.g.
rubber and comprises a set of individual keys 32. Although not shown in the drawing each key 32 is labelled according to its dedicated purpose, for instance a digit "3" or a "*"
sign. A domefoil 40 made from plastics or the like is interposed between the keypad 30 and an electronic circuit ' 30 board 20 arranged inside the telephone housing. The dome-foil 40 is provided with a plurality of tactile domes 42, ' each of which is given a convex shape protruding or bulging from the domefoil 40. One respective dome 42 is arranged beneath one respective key 32 in the keypad 30.
The circuit board 20 is given a purely schematical appearance in FIG 2. The circuit board 20 comprises various electronic circuitry, such as radio transmitter/receiver circuits, amplifiers, filters, buffers, oscillators, mixers, one or several micro-processors, memory modules, etc., none of which are indicated in FIG 2. Furthermore, the circuit board 20 is provided with a set of contact points 22, a respective one of which being arranged in vertical alignment with a respective pair of key 32 and dome 42.
The functional operation of the keypad 30 is as follows. When a key 32 is depressed by a user, the back of the key will excert a force upon the underlying tactile dome 42. The dome 42 will not be able to resist the force excerted by the key 32 but will collapse inwardly/down-wardly and reach contact with the underlying contact point 22. For this purpose the rear side of each dome 42 is made electrically conductive, for instance by providing each dome with a conductive layer, such as a silver or carbon compound. The collapsing dome establishes electric contact between a contact pair at the contact point 22, the details of which are omitted in the drawing, since they are believed to be well-known per se to a man skilled in the art. The electric connection so established is immediately detected by a controller comprised on the circuit board.
Furthermore, the circuit board 20 is provided with illuminating means 24 realized as LEDs (Light Emitting Diodes), the purpose of which is to illuminate the keys 32 through respective openings 44 in the domefoil 40. In FIG 2 one illuminating means 24 is arranged to illuminate four keys 32 surrounding the opening 44. In addition to these openings the domefoil 40 is provided with various holes, openings or recesses 46, 48, 49 for various electronic components or mounting means arranged on the circuit board 2 0 .
, . . ... ..,.. , In the prior art arrangement according to FIG 2 the rubber-based keypad sheet 32 serves as an ESD-protective means. Furthermore, the housing 12 shown in FIG 1 is pro-vided on the inside thereof with a thin metallized layer funtioning as a protection or a shielding against electro-magnetic interference between the telephone 10 and sur-rounding electronic equipment. Although providing a suffi-cient protection against ESD as well as electromagnetic interference, the prior art arrangement according to FIG 2 is disadvantageous when it comes to cost considerations.
Both the keypad rubber sheet 30 and the metallized layer inside the housing 10 add a non-negligable price penalty to the total cost for manufacturing the telephone 10.
The inventive solution according to FIG 3 proposes a less expensive way of providing the telephone with means for protection against ESD. According to the present inven-tion the domefoil 50, with its set of tactile key domes 52, is formed as a sheet fully covering the entire surface be-tween the keypad 30 and the underlying circuit board 20. At least the front surface of the domefoil 50 is made electri-cally non-conductive or isolating, thereby providing an air-tight and/or electrostatic seal between the keypad and the circuit board and thus functioning as an ESD-protective means. In contrast to the prior art domefoil 40 in FIG 2, the inventive domefoil 50 has no open-air openings which would permit an electric spark to be transferred from a key 32 to the circuit board 20. All previous openings, such as the openings for the illuminating means 24, are covered with additional domes 54 of a non-conductive material isolating the circuit board 20 from the keypad 30.
According to the preferred embodiment in FIG 3 the keypad 30 is realized as a keytree made from plastics or the like. Such a keytree structure is previously known per se to be a very cheap way of realizing a keypad function in a communication device. Thanks to the integrated domefoil 50 there is no longer any need for the keypad 30 to be made from rubber or having to act as ESD-protection as well as a means for user interaction.
As mentioned above the domefoil 50 is provided with.
additional domes 54 for the underlying illuminating means 24 (which are realized as LEDs or similar components).
Obviously the additional domes 54 must be made transparent or at least semi-transparent to the light emitted from the illuminating means 24. Preferably the additional domes 54 are made white or glossy so as to give a better illumina-tion of the keypad 30. In an alternative embodiment the additional domes 54 could be printed with a certain screen or dot pattern to direct the light towards the four keys 32 surrounding the dome 54 and the underlying illuminating means 24. This pattern may exhibit lines or dots which are arranged at increasing size or density in the directions of the keys 32.
According to one embodiment of the invention the interior of the domefoil 50 is provided with a layer of electrically conductive material, such as a silver com-pound. The conductive layer is connected to a grounding means so as to function as a means for protection against electromagnetic interference, thereby assuring electro-magnetic compatibility. Hence, the need for a metallized apparatus housing in the prior art arrangement according to FTG 2 has been eliminated, and the domefoil will act as a combined means for protection against ESD as well as electromagnetic interference.
To help dissipating heat generated by the various circuits and components on the electronic circuit board 20 the domefoil 50 may be provided with air channels extending along a major part of the domefoil and reaching some of the edges of the domefoil 50.
The present invention has been described above with reference to a few embodiments or examples, but it is to be ..
WO 98139785 ~ PCTlSE98100208 understood that the invention shall by no means be restric-ted to the specific embodiments disclosed in the foregoing.
On the contrary, the present invention shall only be limited by the scope of the appended patent claims.
Claims (8)
1. A portable communication device (10), comprising an electronic circuit board (20) arranged inside a housing l12), and a keypad (30), the individual keys (32) of which are arranged, when depressed, to collapse a respective tactile dome (52) on a domefoil (50) interposed between the keypad and the circuit board, so as to establish electric contact with a respective contact point (22) on the circuit board, said communication device being provided with means for protecting the circuit board from electrostatic discharge (ESD), characterized in that said domefoil (50) is formed as a non-conductive sheet providing an air-tight and/or electrostatic seal between the keypad (30) and the circuit board (20), said domefoil thereby functioning as said ESD-protective means, and in that an electrically conductive layer is embedded in the domefoil (50) and is connected to ground means, said layer thereby preventing electromagnetic interference between the device and its surroundings.
2. A communication device according to claim 1, wherein said circuit board is provided with means (24) for illuminating the keys (32) in the keypad (30) and said domefoil (50) is provided with additional domes (54) covering the illuminating means (24), thereby protecting the circuit board (20) from ESD.
3. A communication device according to claim 2, wherein said additional domes (54) are made transparent to the light emitted from the illuminating means (24).
4. A communication device according to claim 2, wherein said additional domes (54) are made white or glossy, so as to enhance the illumination of the keys (32) in the keypad (30).
5. A communication device according to claim 2, wherein said additional domes (54) are printed with a screen or dot pattern.
6. A communication device according to any preceding claim, wherein the domefoil (50) is provided with air channels for dissipating heat generated by the circuit board (20) or components thereon.
7. A communication device according to any preceding claim, wherein the device is a radio telephone, preferably a cellular telephone.
8. A method of protecting a keypad-operated device (10) from electrostatic discharge between a keypad (30) and an electronic circuit board (20) inside the device, characterized by providing the device (10) with a domefoil (50), comprising a set of tactile domes (52) and at least the entire front surface of which being made from an electrically isolating material, as an air-tight and/or electrostatic seal between the keypad (30) and the circuit board (20), and by providing the interior of the domefoil (50) with an electrically conductive and grounded layer, said layer acting as an electromagnetic shield between the circuit board (20) and electronic equipment external to the device (10).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9700736A SE513069C2 (en) | 1997-03-03 | 1997-03-03 | Protection against electrostatic discharge in a portable communication device |
| SE9700736-3 | 1997-03-03 | ||
| PCT/SE1998/000208 WO1998039785A1 (en) | 1997-03-03 | 1998-02-06 | Electrostatic discharge protection in a portable communication device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2282446A1 true CA2282446A1 (en) | 1998-09-11 |
Family
ID=20405983
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002282446A Abandoned CA2282446A1 (en) | 1997-03-03 | 1998-02-06 | Electrostatic discharge protection in a portable communication device |
Country Status (19)
| Country | Link |
|---|---|
| US (1) | US6207912B1 (en) |
| EP (1) | EP0965139B1 (en) |
| JP (1) | JP3883014B2 (en) |
| KR (1) | KR100540352B1 (en) |
| CN (1) | CN1169173C (en) |
| AR (1) | AR011924A1 (en) |
| AU (1) | AU732251B2 (en) |
| BR (1) | BR9807813A (en) |
| CA (1) | CA2282446A1 (en) |
| CO (1) | CO4780083A1 (en) |
| DE (1) | DE69832778D1 (en) |
| EE (1) | EE04407B1 (en) |
| HK (1) | HK1027212A1 (en) |
| ID (1) | ID27860A (en) |
| MY (1) | MY123189A (en) |
| NO (1) | NO317121B1 (en) |
| RU (1) | RU2204871C2 (en) |
| SE (1) | SE513069C2 (en) |
| WO (1) | WO1998039785A1 (en) |
Families Citing this family (44)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000182798A (en) * | 1998-12-15 | 2000-06-30 | Olympus Optical Co Ltd | Electronic apparatus operating device |
| DE19906131C2 (en) * | 1999-02-13 | 2001-06-13 | Mannesmann Vdo Ag | Built-in device intended for a motor vehicle |
| AU5675400A (en) * | 1999-06-02 | 2000-12-18 | Telefonaktiebolaget Lm Ericsson (Publ) | Keypad-integrated lcd carrier for mobile telephones |
| FI108186B (en) | 1999-09-29 | 2001-11-30 | Nokia Mobile Phones Ltd | Display frame with integrated ESD protection and user interface structure |
| JP4201068B2 (en) * | 1999-11-12 | 2008-12-24 | パナソニック株式会社 | Portable wireless device |
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- 1997-03-03 SE SE9700736A patent/SE513069C2/en not_active IP Right Cessation
-
1998
- 1998-02-06 RU RU99121193/09A patent/RU2204871C2/en not_active IP Right Cessation
- 1998-02-06 AU AU66402/98A patent/AU732251B2/en not_active Ceased
- 1998-02-06 ID IDW990932D patent/ID27860A/en unknown
- 1998-02-06 EP EP98908352A patent/EP0965139B1/en not_active Expired - Lifetime
- 1998-02-06 KR KR1019997007924A patent/KR100540352B1/en not_active IP Right Cessation
- 1998-02-06 EE EEP199900380A patent/EE04407B1/en not_active IP Right Cessation
- 1998-02-06 JP JP53842298A patent/JP3883014B2/en not_active Expired - Lifetime
- 1998-02-06 BR BR9807813-5A patent/BR9807813A/en not_active IP Right Cessation
- 1998-02-06 CA CA002282446A patent/CA2282446A1/en not_active Abandoned
- 1998-02-06 WO PCT/SE1998/000208 patent/WO1998039785A1/en active IP Right Grant
- 1998-02-06 CN CNB988030373A patent/CN1169173C/en not_active Expired - Fee Related
- 1998-02-06 DE DE69832778T patent/DE69832778D1/en not_active Expired - Lifetime
- 1998-02-24 MY MYPI98000778A patent/MY123189A/en unknown
- 1998-03-02 US US09/032,794 patent/US6207912B1/en not_active Expired - Lifetime
- 1998-03-03 AR ARP980100946A patent/AR011924A1/en active IP Right Grant
- 1998-03-03 CO CO98011457A patent/CO4780083A1/en unknown
-
1999
- 1999-08-27 NO NO19994167A patent/NO317121B1/en not_active Application Discontinuation
-
2000
- 2000-09-29 HK HK00106242A patent/HK1027212A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| AU6640298A (en) | 1998-09-22 |
| CN1169173C (en) | 2004-09-29 |
| CN1249846A (en) | 2000-04-05 |
| EE9900380A (en) | 2000-04-17 |
| ID27860A (en) | 2001-04-26 |
| MY123189A (en) | 2006-05-31 |
| SE9700736L (en) | 1998-09-04 |
| JP2001513941A (en) | 2001-09-04 |
| AU732251B2 (en) | 2001-04-12 |
| JP3883014B2 (en) | 2007-02-21 |
| SE513069C2 (en) | 2000-07-03 |
| WO1998039785A1 (en) | 1998-09-11 |
| BR9807813A (en) | 2000-02-22 |
| SE9700736D0 (en) | 1997-03-03 |
| US6207912B1 (en) | 2001-03-27 |
| EE04407B1 (en) | 2004-12-15 |
| CO4780083A1 (en) | 1999-05-26 |
| KR20000075847A (en) | 2000-12-26 |
| EP0965139A1 (en) | 1999-12-22 |
| HK1027212A1 (en) | 2001-01-05 |
| RU2204871C2 (en) | 2003-05-20 |
| NO994167D0 (en) | 1999-08-27 |
| DE69832778D1 (en) | 2006-01-19 |
| EP0965139B1 (en) | 2005-12-14 |
| KR100540352B1 (en) | 2006-01-12 |
| NO317121B1 (en) | 2004-08-16 |
| AR011924A1 (en) | 2000-09-13 |
| NO994167L (en) | 1999-11-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |