EP1481410B1 - Film keyboard - Google Patents
Film keyboard Download PDFInfo
- Publication number
- EP1481410B1 EP1481410B1 EP03709715A EP03709715A EP1481410B1 EP 1481410 B1 EP1481410 B1 EP 1481410B1 EP 03709715 A EP03709715 A EP 03709715A EP 03709715 A EP03709715 A EP 03709715A EP 1481410 B1 EP1481410 B1 EP 1481410B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- film
- keyboard according
- coating
- conductor
- conductive
- 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.)
- Expired - Fee Related
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Classifications
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- 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
- H01H13/7006—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 comprising a separate movable contact element for each switch site, all other elements being integrated in layers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2209/00—Layers
- H01H2209/014—Layers composed of different layers; Lubricant in between
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2209/00—Layers
- H01H2209/068—Properties of the membrane
- H01H2209/082—Properties of the membrane transparent
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2219/00—Legends
- H01H2219/028—Printed information
- H01H2219/034—Coloured areas
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H2239/00—Miscellaneous
- H01H2239/008—Static electricity considerations
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
- H01H9/02—Bases, casings, or covers
- H01H9/04—Dustproof, splashproof, drip-proof, waterproof, or flameproof casings
- H01H9/042—Explosion-proof cases
Definitions
- the invention relates to a membrane keyboard with a number of operating areas, in particular for use in potentially explosive environments, with a cover sheet of insulating material, an electrically conductive layer located below the cover film and a conductor foil arranged below the conductive layer and having a number of conductor tracks with below Operating areas lying switching elements.
- Non-conductive materials may only be used in potentially explosive atmospheres if measures have been taken to prevent electrostatic charging of such materials.
- Membrane keyboards usually use for training a touched by an operator keyboard top a plastic film to which the above-mentioned problem applies when the membrane keyboard is to be used in a hazardous environment.
- a previously known membrane keyboard of this kind can be taken from DE 199 23 806 C1 or EP 936852.
- the well-known membrane keyboard has a structurally simple guarantee of discharge safety next to each actuation field on a through hole which extends past the conductive layer and the conductor foil and ends at a grounded base plate of the membrane keyboard.
- the through hole with a sufficiently large spacing from the conductive layer and the conductor tracks of the conductor foil, constitutes a type of "lightning conductor" via which the charge applied by an operator to the membrane keypad can be diverted to the underside of the keyboard.
- a crucial precondition for the fact that charges present on the upper side of the membrane keypad can be diverted through the through-hole to the underside of the membrane keypad is that the connection formed through the through-hole is lower resistance to a ground potential than to the conductive layer or the conductor tracks. This is not the case, in particular, if a high-impedance covering forms in the region of the base plate of the known membrane keypad, for example an oxidation layer, which is predetermined to the environment due to the opening formed through the through-hole.
- penetrating substances of increased conductivity in particular fluids, contribute to the creation of a low-resistance connection to the conductive layer and / or the conductor tracks, whereby the functionality of the known membrane keyboard would at least reduced, which represents a blatant security risk especially in hazardous environments.
- the invention is therefore based on the object to provide a membrane keyboard, in which an optionally present on the top of the membrane keyboard electrical charge can be derived in a structurally simple, cost-effective and permanently safe way, so that the membrane keyboard according to the invention can be used in particular in potentially explosive environments is.
- a membrane keypad of the type mentioned in the present invention that the conductor yields, as a conductor is formed film and that at least one contact element, the coating of the cover sheet to create a conductive connection between the cover sheet and at least one held at a certain potential trace permanent touched.
- An essential advantage of the membrane keypad according to the invention is that in this case the electrostatic charge is avoided or permanently safely dissipated in a damaging environment, in contrast to other previously known membrane keyboards, the metal housing or foils for this purpose with conductive admixtures, a low-cost manufacturing process can be maintained while retaining all the benefits of a conventional, colored and abrasion-resistant membrane keyboard.
- the switching elements have buttons in the form of leaf springs, on the sufficient contact pressure contact between two held at different potential interconnects can be produced, one with the leaf spring, the other with a below the leaf spring arranged base element is connected.
- leaf springs By providing leaf springs, switching operations of the membrane keyboard can be realized in a structurally particularly simple manner.
- leaf spring-like feelers give the operator an optimal ease of use, as they give suddenly and clearly noticeable with sufficient pressure load and thereby generate a characteristic crackling noise, which the operator immediately indicates the switching process.
- the conductor foil can have a conductive grid of at least two sets of intersecting conductor tracks.
- the conductive connection according to the invention between at least one conductor track of the conductor foil and the conductive coating of the cover foil can in principle be arranged in each area of the membrane keypad, which leaves the greatest possible design freedom, in particular in the design of the membrane keypad.
- the grid is grounded, ie connected to the ground or ground potential of a control circuit of the membrane keypad according to the invention.
- at least one of the coated cover film permanently touching Contact elements electrically conductively connected to the grid. In this way, a safe dissipation of charges is ensured, which arise on the operator side of the cover sheet or applied by an operator to this.
- a spacer foil with openings in the region of the contact elements is arranged in an advantageous embodiment of the membrane keypad according to the invention between the lacquer layers and the conductor foil.
- the paint layers applied to the coating are colored, in particular multicolored, while the cover film and the coating are preferably transparent at least in the visible wavelength range.
- the different control surfaces of the membrane keypad according to the invention can be identified by an arranged below the cover sheet and thus unresponsive to wear and tear-resistant colored design.
- a carrier plate is arranged below the conductor foil. It is considered particularly advantageous if the carrier plate is designed as a printed circuit board.
- the carrier plate may have at least one display element, which may be formed as a liquid crystal element (LCD), as an LED or as a polymer LED.
- LCD liquid crystal element
- the membrane keypad according to the invention makes it possible to achieve a compact arrangement of all relevant operating and control elements, wherein the cover sheet ensures comprehensive protection of all these elements against damage of a mechanical or other nature.
- the carrier plate is connected to a base film carrying the conductor tracks by a double-adhesive film, whereby an easily produced solid and permanent arrangement is given.
- the coating is not painted in the region of the at least one display element and if the spacer film, the double-adhesive film and the conductor film have a corresponding breakthrough in this region. This ensures that the display element, despite its protected arrangement in the lower region of the membrane keypad according to the invention for the operator from the outside is easily visible.
- the coating of the cover sheet consists of a conductive polymer.
- the cover film in contrast to films made conductive by carbon admixtures, is transparent and therefore optimally suitable for use in the context of the above-described embodiments of the membrane keyboard according to the invention.
- the illustrated keypad on the keyboard top has a cover sheet 1 which is provided on its underside, e.g. by vapor deposition, with a transparent, conductive coating 2 is provided.
- Coating layers 3, 3 ' are applied to the coating 2 for a (multi-) colored design, with at least one window 4 and at least one contacting point 5 being recessed.
- Below the paint layers 3, 3 ' there is a spacer film 6, in the region of the coatings 3' and the contact point 5 openings 7, 7 'for receiving switching and contact elements 8 and 8' in the form of leaf springs 8, 8 ' having.
- the membrane keyboard shown has a conductor foil 9 which consists of a base film 11 coated with conductor tracks 10, 10 ', 10.1, 10.2 of silver lacquer. In the area of the strip conductors 10 'or 10.1., 10.2, further switching elements are arranged as base elements 12, 12' below the leaf springs 8, 8 '.
- the base film 11 of the illustrated membrane keyboard is connected by a double-adhesive film 13 fixed to a printed circuit board 14, on the underside 15 in the region of the window 4, a liquid crystal display 16 is arranged.
- the leaf spring 8 'and the associated base member 12' are contacting Conductor tracks 10 'connected to a ground potential of a control circuit (not shown).
- the leaf spring 8 ' contacts the conductive coating 2 of the cover film 1 at the non-lacquered point 5 directly and permanently, creating a conductive connection at least between the grounded conductor 10' and the cover film 1.
- the conductor tracks 10.1, 10.2, which comprise the switching elements 8, 12 contact (of which only a pair is shown in the section of FIG. 1), are at different potentials U 1 and U 2 , so that in the case of a caused by the operator depression of the leaf spring 8 on the base member 12 in the control circuit a switching operation, for example by switching operation of a transistor (not shown), can be triggered.
- the cover sheet 1 is a clear, transparent polyester plastic film having a thickness of less than 200 micrometers, so that electrostatic charging is minimized. It serves as a protective layer for the membrane keyboard.
- the coating 2 is formed as a conductive polymer layer and is preferably applied to the cover sheet 1 by vapor deposition. It serves on the basis of their contact over the entire surface of the cover sheet 1 and the over the contact element 8 ', 12' secured conductive connection to the ground potential of the control circuit of the safe dissipation of electrostatic charges.
- the coating 2 has a shielding effect with regard to the electromagnetic compatibility (EMC) of the membrane keypad according to the invention.
- EMC electromagnetic compatibility
- the membrane keypad according to the invention and in particular the polymer layer 2 is abrasion resistant.
- Leaf springs 8 can increase the ease of use of the membrane keypad invention.
- FIG. 2 shows in detail the arrangement of the conductor tracks 10, 10 ', 10.1, 10.2 on the surface of the base film 11.
- the conductor tracks 10 are partially in.
- FIG Formed a diamond-shaped grid 17, which is formed from two flocks 18,18 'intersecting straight conductor tracks 10.
- the grid 17 and the tracks 10 are connected via a contact lug 19 with a control circuit, not shown.
- at least the interconnects 18,18 'forming the grid 17, and the interconnects 10', which contact the leaf springs acting as contact elements 8 'and even in the embodiment shown are part of the grid, at the ground potential of the control circuit.
- FIG. 3 shows an embodiment of the cover sheet 1 of the membrane keypad according to the invention after the coating 2 has been applied and the lacquer layers 3, 3 'have been applied.
- various control surfaces 20, which are arranged above the leaf springs 8 of Figures 1 and 2, highlighted by differently colored lacquer layers 3 'against a background lacquer layer 3 of the membrane keypad according to the invention.
- the cover film 1 or the coating 2 is free of lacquer, so that contacting of the coating 2 by the leaf springs 8 'in the manner shown in FIG. 1 can take place in these regions.
Landscapes
- Push-Button Switches (AREA)
Description
Die Erfindung betrifft eine Folientastatur mit einer Anzahl von Betätigungsbereichen, insbesondere zur Verwendung in explosionsgefährdeter Umgebung, mit einer Deckfolie aus Isoliermaterial, einer unterhalb der Deckfolie befindlichen elektrisch leitfähigen Schicht und einer isoliert gegenüber der leitfähigen Schicht angeordneten, eine Anzahl von Leiterbahnen aufweisenden Leiterfolie mit unterhalb der Betätigungsbereiche liegenden Schaltelementen.The invention relates to a membrane keyboard with a number of operating areas, in particular for use in potentially explosive environments, with a cover sheet of insulating material, an electrically conductive layer located below the cover film and a conductor foil arranged below the conductive layer and having a number of conductor tracks with below Operating areas lying switching elements.
Nichtleitende Werkstoffe dürfen in explosionsgefährdeten Bereichen nur dann eingesetzt werden, wenn Vorkehrungen zur Vermeidung elektrostatischer Aufladung derartiger Werkstoffe getroffen wurden. Folientastaturen verwenden in aller Regel zur Ausbildung einer von einer Bedienperson berührten Tastaturoberseite eine Kunststofffolie, auf die die vorstehend geschilderte Problematik zutrifft, wenn die Folientastatur in einer explosionsgefährdeten Umgebung eingesetzt werden soll.Non-conductive materials may only be used in potentially explosive atmospheres if measures have been taken to prevent electrostatic charging of such materials. Membrane keyboards usually use for training a touched by an operator keyboard top a plastic film to which the above-mentioned problem applies when the membrane keyboard is to be used in a hazardous environment.
Eine vorbekannte Folientastatur dieser Art ist der DE 199 23 806 C1 oder der EP 936852 entnehmbar. Die bekannte Folientastatur weist zur konstruktiv einfachen Gewährleistung einer Entladungssicherheit neben jedem Betätigungsfeld ein Durchgangsloch auf, das an der leitenden Schicht und an der Leiterfolie vorbei verläuft und an einer geerdeten Grundplatte der Folientastatur endet. Das Durchgangsloch stellt bei ausreichend großer Beabstandung von der leitenden Schicht und den Leiterbahnen der Leiterfolie eine Art "Blitzableiter" dar, über den die von einer Bedienperson auf die Folientastatur aufgebrachte Ladung zur Unterseite der Tastatur ableitbar ist.A previously known membrane keyboard of this kind can be taken from DE 199 23 806 C1 or EP 936852. The well-known membrane keyboard has a structurally simple guarantee of discharge safety next to each actuation field on a through hole which extends past the conductive layer and the conductor foil and ends at a grounded base plate of the membrane keyboard. The through hole, with a sufficiently large spacing from the conductive layer and the conductor tracks of the conductor foil, constitutes a type of "lightning conductor" via which the charge applied by an operator to the membrane keypad can be diverted to the underside of the keyboard.
Eine entscheidende Voraussetzung dafür, dass auf der Oberseite der Folientastatur vorhandene Ladungen durch das Durchgangsloch zur Unterseite der Folientastatur abgeleitet werden können, ist, dass die durch das Durchgangsloch gebildete Verbindung zu einem Massepotential niederohmiger ist als zu der leitenden Schicht bzw. den Leiterbahnen. Dies ist insbesondere dann nicht gegeben, wenn sich im Bereich der Grundplatte der bekannten Folientastatur ein hochohmiger Belag bildet, beispielsweise eine Oxidationsschicht, was aufgrund der durch das Durchgangsloch gebildeten Öffnung zur Umgebung vorgezeichnet ist. Darüber hinaus können in das Durchgangsloch eindringende Substanzen erhöhter Leitfähigkeit, insbesondere Fluide, zur Schaffung einer niederohmigen Verbindung zu der leitenden Schicht und/oder den Leiterbahnen beitragen, wodurch die Funktionsfähigkeit der bekannten Folientastatur zumindest herabgesetzt wäre, was gerade in explosionsgefährdeter Umgebung ein eklatantes Sicherheitsrisiko darstellt.A crucial precondition for the fact that charges present on the upper side of the membrane keypad can be diverted through the through-hole to the underside of the membrane keypad is that the connection formed through the through-hole is lower resistance to a ground potential than to the conductive layer or the conductor tracks. This is not the case, in particular, if a high-impedance covering forms in the region of the base plate of the known membrane keypad, for example an oxidation layer, which is predetermined to the environment due to the opening formed through the through-hole. In addition, in the through hole penetrating substances of increased conductivity, in particular fluids, contribute to the creation of a low-resistance connection to the conductive layer and / or the conductor tracks, whereby the functionality of the known membrane keyboard would at least reduced, which represents a blatant security risk especially in hazardous environments.
Weitere vorbekannte Folientastaturen verwenden zur Ableitung elektrischer Ladung Metallgehäuse oder Folien mit leitfähiger Beimischung als Deckfolien, wobei das Vorsehen eines Metallgehäuses mit zusätzlichen Kosten für Stanzwerkzeug, Lackierung, Erdungsanschluss etc. verbunden ist. Leitfähige Folien sind aufgrund von Karbonbeimischungen immer schwarz gefärbt, weshalb sie nicht - wie zur Schaffung farblich gegeneinander abgegrenzter Betätigungsfelder allgemein üblich - von der Rückseite lackierbar sind.Other known membrane keyboards use for deriving electrical charge metal housing or films with conductive admixture as cover films, the provision of a metal housing with additional costs for punching, painting, grounding connection, etc. is connected. Conductive foils are always dyed black due to carbon admixtures, which is why they are not paintable from the back - as is common for creating colorically contrasted fields of activity.
Der Erfindung liegt daher die Aufgabe zugrunde, eine Folientastatur zu schaffen, bei der sich eine ggf. auf der Oberseite der Folientastatur vorhandene elektrische Ladung auf konstruktiv einfache, kostengünstige und dabei dauerhaft sichere Weise ableiten lässt, so dass die erfindungsgemäße Folientastatur insbesondere in explosionsgefährdeter Umgebung einsetzbar ist.The invention is therefore based on the object to provide a membrane keyboard, in which an optionally present on the top of the membrane keyboard electrical charge can be derived in a structurally simple, cost-effective and permanently safe way, so that the membrane keyboard according to the invention can be used in particular in potentially explosive environments is.
Diese Aufgabe ist bei einer Folientastatur der eingangs genannten Art erfindungsgemäß dadurch gelöst, dass der Leiterträge, als Leiter folie ausgebildet ist und dass mindestens ein Kontaktelement die Beschichtung der Deckfolie unter Schaffung einer leitfähigen Verbindung zwischen der Deckfolie und wenigstens einer auf einem bestimmten Potential gehaltenen Leiterbahn permanent berührt.This object is achieved in a membrane keypad of the type mentioned in the present invention that the conductor yields, as a conductor is formed film and that at least one contact element, the coating of the cover sheet to create a conductive connection between the cover sheet and at least one held at a certain potential trace permanent touched.
Ein wesentlicher Vorteil der erfindungsgemäßen Folientastatur ist, dass hierbei die elektrostatische Aufladung vermieden bzw. auch in schädigender Umgebung dauerhaft sicher abgeleitet wird, wobei im Gegensatz zu weiteren vorbekannten Folientastaturen, die hierzu Metallgehäuse oder Folien mit leitfähigen Beimischungen verwenden, ein preisgünstiger Fertigungsprozess beibehalten werden kann und zugleich alle Vorzüge einer herkömmlich, farbigen und abriebfesten Folientastatur erhalten bleiben.An essential advantage of the membrane keypad according to the invention is that in this case the electrostatic charge is avoided or permanently safely dissipated in a damaging environment, in contrast to other previously known membrane keyboards, the metal housing or foils for this purpose with conductive admixtures, a low-cost manufacturing process can be maintained while retaining all the benefits of a conventional, colored and abrasion-resistant membrane keyboard.
Bei einer besonders bevorzugten Ausführungsform der erfindungsgemäßen Folientastatur weisen die Schaltelemente Taster in Form von Blattfedern auf, über die bei ausreichender Druckbelastung ein Kontakt zwischen jeweils zwei auf unterschiedlichem Potential gehaltenen Leiterbahnen herstellbar ist, von denen eine mit der Blattfeder, die andere mit einem unterhalb der Blattfeder angeordneten Basiselement verbunden ist. Durch das Vorsehen von Blattfedern lassen sich Schaltvorgänge der Folientastatur auf konstruktiv besonders einfache Weise realisieren. Zudem vermitteln blattfederartige Taster dem Bediener einen optimalen Bedienungskomfort, da sie bei ausreichender Druckbelastung plötzlich und deutlich spürbar nachgeben und dabei ein charakteristisches Knackgeräusch erzeugen, was dem Bediener den erfolgten Schaltvorgang unmittelbar anzeigt.In a particularly preferred embodiment of the membrane keypad according to the invention, the switching elements have buttons in the form of leaf springs, on the sufficient contact pressure contact between two held at different potential interconnects can be produced, one with the leaf spring, the other with a below the leaf spring arranged base element is connected. By providing leaf springs, switching operations of the membrane keyboard can be realized in a structurally particularly simple manner. In addition, leaf spring-like feelers give the operator an optimal ease of use, as they give suddenly and clearly noticeable with sufficient pressure load and thereby generate a characteristic crackling noise, which the operator immediately indicates the switching process.
Die Leiterfolie kann nach einer weiteren Ausgestaltung der erfindungsgemäßen Folientastatur ein leitfähiges Gitter aus mindestens zwei Scharen sich kreuzender Leiterbahnen aufweisen. Auf diese Weise ist sichergestellt, dass die erfindungsgemäße leitfähige Verbindung zwischen wenigstens einer Leiterbahn der Leiterfolie und der leitenden Beschichtung der Deckfolie prinzipiell in jedem Bereich der Folientastatur angeordnet sein kann, was einen größtmöglichen Gestaltungsspielraum insbesondere beim Design der Folientastatur lässt. In einer äußerst bevorzugten Ausgestaltung der Erfindung ist das Gitter geerdet, d.h. mit dem Erd- oder Massepotential einer Steuerschaltung der erfindungsgemäßen Folientastatur verbunden. Zusätzlich ist vorzugsweise mindestens eines der die beschichtete Deckfolie permanent berührenden Kontaktelemente elektrisch leitend mit dem Gitter verbunden. Auf diese Weise ist eine sichere Ableitung von Ladungen gewährleistet, die auf der Bedienerseite der Deckfolie entstehen oder von einer Bedienperson auf diese aufgebracht werden.According to a further embodiment of the membrane keypad according to the invention, the conductor foil can have a conductive grid of at least two sets of intersecting conductor tracks. In this way it is ensured that the conductive connection according to the invention between at least one conductor track of the conductor foil and the conductive coating of the cover foil can in principle be arranged in each area of the membrane keypad, which leaves the greatest possible design freedom, in particular in the design of the membrane keypad. In an extremely preferred embodiment of the invention, the grid is grounded, ie connected to the ground or ground potential of a control circuit of the membrane keypad according to the invention. In addition, preferably at least one of the coated cover film permanently touching Contact elements electrically conductively connected to the grid. In this way, a safe dissipation of charges is ensured, which arise on the operator side of the cover sheet or applied by an operator to this.
Zur Sicherstellung eines notwendigen Schaltabstandes zwischen den blattfederartigen Tastern und Basiselektroden der Kontaktelemente ist bei einer vorteilhaften Ausführungsform der erfindungsgemäßen Folientastatur zwischen den Lackschichten und der Leiterfolie eine Abstandfolie mit Durchbrüchen im Bereich der Kontaktelemente angeordnet.To ensure a necessary switching distance between the leaf spring-like buttons and base electrodes of the contact elements, a spacer foil with openings in the region of the contact elements is arranged in an advantageous embodiment of the membrane keypad according to the invention between the lacquer layers and the conductor foil.
Nach einer weiteren vorteilhaften Ausgestaltung der Erfindung sind die auf die Beschichtung aufgebrachten Lackschichten farbig, insbesondere mehrfarbig ausgebildet, während die Deckfolie und die Beschichtung vorzugsweise zumindest im sichtbaren Wellenlängenbereich transparent sind. Auf diese Weise lassen sich die unterschiedlichen Bedienflächen der erfindungsgemäßen Folientastatur durch ein unterhalb der Deckfolie angeordnetes und somit gegen bedienungsbedingte Abnutzungserscheinungen unanfälliges farbiges Design kenntlich machen.According to a further advantageous embodiment of the invention, the paint layers applied to the coating are colored, in particular multicolored, while the cover film and the coating are preferably transparent at least in the visible wavelength range. In this way, the different control surfaces of the membrane keypad according to the invention can be identified by an arranged below the cover sheet and thus unresponsive to wear and tear-resistant colored design.
Weiterhin ist bei einer anderen Ausführungsform der Erfindung vorgesehen, dass unterhalb der Leiterfolie eine Trägerplatte angeordnet ist. Als besonders vorteilhaft wird es angesehen, wenn die Trägerplatte als Leiterplatte ausgebildet ist. In einer weiteren bevorzugten Ausführungsform der erfindungsgemäßen Folientastatur kann die Trägerplatte mindestens ein Anzeigeelement aufweisen, das als Flüssigkristallelement (LCD), als LED oder auch als Polymer-LED ausgebildet sein kann. Auf diese Weise lässt sich durch die erfindungsgemäße Folientastatur eine kompakte Anordnung sämtlicher relevanter Bedien- und Kontrollelemente erreichen, wobei die Deckfolie einen umfassenden Schutz aller dieser Elemente gegen Schadeinwirkungen mechanischer oder anderer Art gewährleistet.Furthermore, in another embodiment of the invention, it is provided that a carrier plate is arranged below the conductor foil. It is considered particularly advantageous if the carrier plate is designed as a printed circuit board. In a further preferred embodiment of the membrane keypad according to the invention, the carrier plate may have at least one display element, which may be formed as a liquid crystal element (LCD), as an LED or as a polymer LED. In this way, the membrane keypad according to the invention makes it possible to achieve a compact arrangement of all relevant operating and control elements, wherein the cover sheet ensures comprehensive protection of all these elements against damage of a mechanical or other nature.
Bei einer vorteilhaften Ausführungsform der erfindungsgemäßen Folientastatur ist die Trägerplatte mit einer die Leiterbahnen tragenden Basisfolie durch eine Doppelklebefolie verbunden, wodurch eine einfach herstellbare feste und dauerhafte Anordnung gegeben ist.In an advantageous embodiment of the membrane keypad according to the invention, the carrier plate is connected to a base film carrying the conductor tracks by a double-adhesive film, whereby an easily produced solid and permanent arrangement is given.
Besonders vorteilhaft ist es, wenn die Beschichtung im Bereich des mindestens einen Anzeigeelements nicht lackiert ist und wenn die Abstandfolie, die Doppelklebefolie sowie die Leiterfolie in diesem Bereich einen entsprechenden Durchbruch aufweisen. Dadurch ist sichergestellt, dass das Anzeigeelement trotz seiner geschützten Anordnung im unteren Bereich der erfindungsgemäßen Folientastatur für den Bediener von außen problemlos einsehbar ist.It is particularly advantageous if the coating is not painted in the region of the at least one display element and if the spacer film, the double-adhesive film and the conductor film have a corresponding breakthrough in this region. This ensures that the display element, despite its protected arrangement in the lower region of the membrane keypad according to the invention for the operator from the outside is easily visible.
Nach einer äußerst bevorzugten Ausgestaltung der Erfindung besteht die Beschichtung der Deckfolie aus einem leitfähigen Polymer. Bei derartiger Beschichtung ist die Deckfolie im Gegensatz zu durch Karbonbeimischungen leitfähig gemachten Folien transparent und daher für eine Verwendung im Rahmen der vorstehend beschriebenen Ausführungsformen der erfindungsgemäßen Folientastatur optimal geeignet.According to an extremely preferred embodiment of the invention, the coating of the cover sheet consists of a conductive polymer. In the case of such a coating, the cover film, in contrast to films made conductive by carbon admixtures, is transparent and therefore optimally suitable for use in the context of the above-described embodiments of the membrane keyboard according to the invention.
Weitere vorteilhafte Ausgestaltungen der Erfindung ergeben sich aus der folgenden Beschreibung, in der ein Ausführungsbeispiel anhand der Zeichnung näher erläutert ist. Dabei zeigt:
- Fig. 1
- in einer schematischen Schnittansicht etwa entlang der Linie A-A' der Fig. 2 eine Ausführungsform der erfindungsgemäßen Folientastatur;
- Fig. 2
- eine weitere Schnittansicht einer Ausführungsform der erfindungsgemäßen Folientastatur entlang der Linie B-B' der Fig. 1; und
- Fig. 3
- eine Draufsicht auf eine Ausführungsform der Deckfolie der erfindungsgemäßen Folientastatur.
- Fig. 1
- in a schematic sectional view approximately along the line AA 'of Fig. 2, an embodiment the membrane keypad according to the invention;
- Fig. 2
- a further sectional view of an embodiment of the membrane keyboard according to the invention along the line BB 'of Fig. 1; and
- Fig. 3
- a plan view of an embodiment of the cover sheet of the membrane keypad according to the invention.
Wie in Fig. 1 gezeigt ist, weist die dargestellte Folientastatur auf der Tastaturoberseite eine Deckfolie 1 auf, die auf ihrer Unterseite, z.B. durch Bedampfen, mit einer transparenten, leitfähigen Beschichtung 2 versehen ist. Auf die Beschichtung 2 sind für ein (mehr-)farbiges Design Lackschichten 3, 3' aufgetragen, wobei mindestens ein Fenster 4 sowie mindestens ein Kontaktierungspunkt 5 ausgespart sind. Unterhalb der Lackschichten 3, 3' befindet sich eine Abstandfolie 6, die im Bereich der Lackierungen 3' bzw. des Kontaktierungspunkts 5 Durchbrüche 7, 7' zur Aufnahme von Schalt- und Kontaktelementen 8 bzw. 8' in Form von Blattfedern 8, 8' aufweist.As shown in Fig. 1, the illustrated keypad on the keyboard top has a
Unterhalb der Abstandfolie 6 weist die dargestellte Folientastatur eine Leiterfolie 9 auf, die aus einer mit Leiterbahnen 10, 10', 10.1, 10.2 aus Silberlack beschichteten Basisfolie 11 besteht. Im Bereich der Leiterbahnen 10' bzw. 10.1.,10.2 sind weitere Schaltelemente als Basiselemente 12, 12' unterhalb der Blattfedern 8, 8' angeordnet. Die Basisfolie 11 der dargestellten Folientastatur ist durch eine Doppelklebefolie 13 fest mit einer Leiterplatte 14 verbunden, an deren Unterseite 15 im Bereich des Fensters 4 eine Flüssigkristallanzeige 16 angeordnet ist.Below the
Beim gezeigten Ausführungsbeispiel sind die die Blattfeder 8' und das zugehörige Basiselement 12' kontaktierenden Leiterbahnen 10' mit einem Masse- bzw. Erdpotential einer Steuerschaltung (nicht gezeigt) verbunden. Die Blattfeder 8' kontaktiert die leitfähige Beschichtung 2 der Deckfolie 1 an der nicht-lackierten Stelle 5 direkt und dauerhaft unter Schaffung einer leitenden Verbindung zumindest zwischen der geerdeten Leiterbahn 10' und der Deckfolie 1. Die Leiterbahnen 10.1,10.2, die die Schaltelemente 8,12 kontaktieren (von denen im Schnitt der Fig. 1 nur ein Paar gezeigt ist), befinden sich auf unterschiedlichen Potentialen U1 bzw. U2, so dass im Falle eines durch die Bedienperson bewirkten Niederdrückens der Blattfeder 8 auf das Basiselement 12 in der Steuerschaltung ein Schaltvorgang, beispielsweise durch Schaltbetrieb eines Transistors (nicht gezeigt), auslösbar ist.In the embodiment shown, the leaf spring 8 'and the associated base member 12' are contacting Conductor tracks 10 'connected to a ground potential of a control circuit (not shown). The leaf spring 8 'contacts the conductive coating 2 of the
In dem dargestellten Beispiel der erfindungsgemäßen Folientastatur ist die Deckfolie 1 eine klare, durchsichtige Polyester-Kunststofffolie mit einer Dicke von weniger als 200 Mikrometer, so dass eine elektrostatische Aufladung minimiert wird. Sie dient als Schutzschicht für die Folientastatur. Die Beschichtung 2 ist als leitfähige Polymerschicht ausgebildet und wird vorzugsweise durch Bedampfen auf die Deckfolie 1 aufgebracht. Sie dient aufgrund ihrer ganzflächigen Kontaktierung der Deckfolie 1 sowie der über das Kontaktelement 8',12' sichergestellten leitfähigen Verbindung zum Massepotential der Steuerschaltung der sicheren Ableitung elektrostatischer Ladungen. Zusätzlich besitzt die Beschichtung 2 eine Schirmwirkung hinsichtlich der elektromagnetischen Verträglichkeit (EMV) der erfindungsgemäßen Folientastatur.In the illustrated example of the membrane keypad according to the invention, the
Durch die Lackschichten 3, 3' wird die erfindungsgemäße Folientastatur und insbesondere die Polymerschicht 2 abriebfest. Durch ein mehrfarbiges Design der Lackschichten 3, 3' insbesondere im Bereich 3' der als Bedienelemente fungierenden Blattfedern 8 lässt sich die Bedienfreundlichkeit der erfindungsgemäßen Folientastatur erhöhen.Through the
Der in Fig. 2 gezeigte Schnitt entlang der Linie B-B' der Fig. 1 zeigt detailliert die Anordnung der Leiterbahnen 10,10',10.1,10.2 an der Oberfläche der Basisfolie 11. Wie aus Fig. 2 ersichtlich, sind die Leiterbahnen 10 teilweise in Form eines rautenförmigen Gitters 17 angeordnet, das aus zwei Scharen 18,18' sich schneidender gerader Leiterbahnen 10 gebildet ist. Das Gitter 17 und die Leiterbahnen 10 sind über eine Kontaktfahne 19 mit einer nicht gezeigten Steuerschaltung verbunden. Dabei liegen zumindest die Leiterbahnen 18,18' die das Gitter 17 bilden, und die Leiterbahnen 10', die die als Kontaktelemente fungierenden Blattfedern 8' kontaktieren und selbst beim gezeigten Ausführungsbeispiel Teil des Gitters sind, auf dem Massepotential der Steuerschaltung.2 shows in detail the arrangement of the
Fig. 3 zeigt ein Ausführungsbeispiel der Deckfolie 1 der erfindungsgemäßen Folientastatur nach erfolgtem Aufbringen der Beschichtung 2 sowie der Lackschichten 3, 3'. Durch farbliche Unterschiede zwischen den verschiedenen Lackschichten 3, 3' lässt sich ein bedienfreundliches, insbesondere mehrfarbiges Design der erfindungsgemäßen Folientastatur erreichen. Beim dargestellten Ausführungsbeispiel sind diverse Bedienflächen 20, die oberhalb der Blattfedern 8 der Figuren 1 und 2 angeordnet sind, durch andersfarbige Lackschichten 3' gegenüber einer Hintergrund-Lackschicht 3 der erfindungsgemäßen Folientastatur hervorgehoben. In zwei dargestellten Bereichen 5 ist die Deckfolie 1 bzw. die Beschichtung 2 lackfrei, so dass in diesen Bereichen eine Kontaktierung der Beschichtung 2 durch die Blattfedern 8' auf die in Fig. 1 gezeigte Weise erfolgen kann.FIG. 3 shows an embodiment of the
Claims (15)
- Film keyboard with a plurality of operating areas, particularly for use in explosion-endangered environments, with a cover film (1) of insulating material, an electrically conductive layer below the cover film (1), the conductive layer (2) being in the form of a conductive material coating (2) applied to the inside of the cover film (1), and in which the coating (2) has an electrically insulating lacquer coating (3, 3') at least in partial areas (3') above the switching elements (8), and with a conductor carrier (9) having a plurality of conducting tracks (19), which is insulated with respect to the conductive layer and with switching elements located below the operating areas, characterized in that the conductor carrier is constructed as a conductor film and that at least one contact element (8') is in permanent contact with the coating (2) of cover film (1), accompanied by the creation of a conductive connection between the cover film (1) and at least one conducting track (10') kept at a given potential.
- Film keyboard according to claim 1, characterized in that the switching elements (8) have key switches in the form of leaf springs.
- Film keyboard according to claim 1 or 2, characterized in that the conductor film (9) has a conductive grid (17) of at least two groups (18, 18') of mutually crossing conducting tracks (10).
- Film keyboard according to claim 3, characterized in that the grid (17) is earthed.
- Film keyboard according to claim 4, characterized in that at least one contact element (8) permanently contacting the coating (2) of cover film (1) is electrically conductively connected to grid (17).
- Film keyboard according to one of the preceding claims, characterized in that a spacing film (6) with openings (7, 7') is placed in the vicinity of the contact element (8') and switching element (8) between lacquer coatings (3, 3') and conductor film (9).
- Film keyboard according to one of the preceding claims, characterized in that the lacquer coatings (3, 3') are coloured, particularly multicoloured.
- Film keyboard according to one of the preceding claims, characterized in that the cover film (1) and conductive coating (2) are transparent, at least in the visible wavelength range.
- Film keyboard according to one of the preceding claims, characterized in that a mounting plate (14) is placed beneath the conductor film (9).
- Film keyboard according to claim 9, characterized in that the mounting plate (14) is constructed as a printed circuit board.
- Film keyboard according to claim 10, characterized in that the mounting plate (14) has at least one display element (16).
- Film keyboard according to claim 11, characterized in that the display element (16) is constructed as a liquid crystal element.
- Film keyboard according to one of the claims 9 to 12, characterized in that the mounting plate (14) is connected by a double adhesive film (13) to a base film (11) carrying the conducting tracks (10).
- Film keyboard according to one of the claims 11 to 13, characterized in that the coating (2) is not lacquered in the vicinity of the at least one display element (16) and that the spacing film (6), double adhesive film (13) and conductor film (9) have a corresponding opening (4) in this area.
- Film keyboard according to one of the preceding claims, characterized in that the coating (2) is made from a conductive polymer.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE2002109079 DE10209079A1 (en) | 2002-03-01 | 2002-03-01 | keypad |
DE10209079 | 2002-03-01 | ||
PCT/EP2003/001735 WO2003075297A1 (en) | 2002-03-01 | 2003-02-20 | Film keyboard |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1481410A1 EP1481410A1 (en) | 2004-12-01 |
EP1481410B1 true EP1481410B1 (en) | 2006-10-18 |
Family
ID=27770920
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP03709715A Expired - Fee Related EP1481410B1 (en) | 2002-03-01 | 2003-02-20 | Film keyboard |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP1481410B1 (en) |
AU (1) | AU2003214067A1 (en) |
DE (2) | DE10209079A1 (en) |
WO (1) | WO2003075297A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE50313616D1 (en) | 2003-09-09 | 2011-05-26 | Schurter Input Systems Ag | Illuminated keyboard element for a keypad |
DE102005002149A1 (en) | 2005-01-17 | 2006-07-20 | Printed Systems Gmbh | Keyboard and method of making a keyboard |
DE102005053929A1 (en) * | 2005-11-11 | 2007-05-16 | Bsh Bosch Siemens Hausgeraete | Operating unit for e.g. stove top, has cover surface and pressure sensor, arranged within top plate, so that plate forms counter surface for pressure sensor having electrodes that are arranged opposite to sides of cover surface and plate |
EP2400363A1 (en) * | 2010-06-23 | 2011-12-28 | Siemens Aktiengesellschaft | Control device for operating an automated machine |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4303960A (en) * | 1979-12-31 | 1981-12-01 | Gte Products Corporation | Electrostatic discharge-protected switch |
JPS6170247U (en) * | 1984-10-05 | 1986-05-14 | ||
DE8914142U1 (en) * | 1989-11-30 | 1990-02-01 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Switch foil |
DE4437616C2 (en) * | 1994-05-13 | 1997-03-06 | Kundisch Gmbh & Co Kg | Process for the production of front foils for membrane keyboards or the like |
DE29505969U1 (en) * | 1994-10-21 | 1995-06-14 | Celfa Ag, Seewen | Front foil for membrane keyboards or the like. |
DE29501466U1 (en) * | 1995-01-31 | 1995-03-30 | Celfa Ag, Seewen | Transparent film, in particular for the production of front films for membrane keyboards or the like. |
KR970049350A (en) * | 1995-12-19 | 1997-07-29 | 윤종용 | Touch panel |
CN1129154C (en) * | 1997-07-31 | 2003-11-26 | 株式会社丰臣 | Console panel for equipment |
US6199996B1 (en) | 1998-08-26 | 2001-03-13 | Twenty-First Century Technology, Inc. | Low power, low cost illuminated keyboards and keypads |
DE19923806C1 (en) * | 1999-05-19 | 2001-02-08 | Siemens Ag | Thin film keyboard |
DE10040151C1 (en) * | 2000-08-17 | 2002-01-31 | Schurter Gmbh | Keyboard for reliable triggering of electrical switching functions has less frequently operated keys made using less expensive technology than frequently used keys |
-
2002
- 2002-03-01 DE DE2002109079 patent/DE10209079A1/en not_active Withdrawn
-
2003
- 2003-02-20 AU AU2003214067A patent/AU2003214067A1/en not_active Abandoned
- 2003-02-20 WO PCT/EP2003/001735 patent/WO2003075297A1/en active IP Right Grant
- 2003-02-20 EP EP03709715A patent/EP1481410B1/en not_active Expired - Fee Related
- 2003-02-20 DE DE50305415T patent/DE50305415D1/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
EP1481410A1 (en) | 2004-12-01 |
WO2003075297A1 (en) | 2003-09-12 |
DE50305415D1 (en) | 2006-11-30 |
AU2003214067A1 (en) | 2003-09-16 |
DE10209079A1 (en) | 2003-10-16 |
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