DE2024984A1 - Membrane switchgear - Google Patents

Description

202A98A

IBM Germany Internationale Büro-Matchinen Getelhchaft mbH

Boeblingen, May 14, 1970 ar-ba

Applicant: International Business Machines

Corporation, Armonk, N.Y. 10504

Official File number: New registration

Applicant's file number: Docket YO 9-69-017

Membrane switching device

This invention relates to a pressure sensitive membrane switch device with at least one electrical conductor fastened on an insulating base layer and at least one at a small distance above it on the underside of an insulating elastomeric membrane arranged electrical conductor, whose Direction intersects with the conductor on the base layer.

Such membrane switching devices only require a very large amount small actuation force and an extremely small actuation stroke and also have the advantage that on a unit area a relatively large number of switching points can be accommodated. Due to their small dimensions, the light weight Weight and their compact arrangement are membrane switching devices as manual keyboards, as simple electrical membrane switches, as multiple switches, as matrix switches in control circuits, Used in measuring and precision engineering or as an input station in data processing systems,

The American patent 3 308 253 made a printing

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sensitive membrane switch known for several switching points, which in principle has the structure described below. On an electrically insulating, solid and dimensionally stable base layer a number of electrical conductors are attached parallel and spaced apart, the ends connected to connection points are. At a short distance above these conductors there is a membrane, also on the underside of which there are a number parallel conductors are attached., which extend in their longitudinal direction however, extend transversely to the longitudinal direction of the conductors arranged on the base layer. The crossing points of the in two planes lying conductors form the individual switching points or /. when pressed together, the contact parts. These superimposed Conductors are through an insulating intermediate layer that fills the interspace and that is placed at the intersections of the Conductor each has an opening, normally separated and isolated from one another. Through this intermediate layer, the distance between the Overlying conductors are preserved and thus the open switching state is defined, over the membrane is mostly to their Protection by an elastic pressure layer. Used with a fingertip or a blunt pen on one point of the top layer, under which there is a conductor crossing point and an opening in the intermediate layer, a slight pressure is applied, then the membrane and the attached conductor piece pressed into the opening of the intermediate layer until this conductor on the underlying conductor of the base layer rests. These two conductors touching one another thus form a closed one Contact or switching point. As soon as the action of the compressive force stops, this contact point opens.

Although this known membrane switch in comparison with other electromechanical multiple switches, which also have several Switching points are relatively very small and have other advantages, it also fulfills all the new line requirements, the Mexnbran-Schalteinriafatungen in the data processing and control technology. It has been recognized, that Membrane holding devices except as keyboard input stations

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also for entering handwritten patterns, curves, answers or other records can serve, or that membrane switching devices as electromechanical readers for identifying raised characters on ID cards or credit cards and others are advantageously usable provided that the Switching parts in the membrane switching device in such a Density arranged so that a large resolution of the inscribed or read character pattern. With the known Membrane switch designs is the required resolution not achievable, and their sensitivity is still too low,

The invention is therefore based on the object of the membrane switching device to be designed so that a very large number of switching points, which are isolated from each other, can be accommodated on one surface unit, so that a large resolution, a sharp demarcation of the respective switching point and a high sensitivity with good operational reliability result.

According to the invention, this object is achieved in that the conductors, with the exception of the intersections forming a switching point, with their distance from each other determining electrically insulating material are surrounded.

This Merabranehalteinrichtung invention differs is essentially different from the one mentioned as known. ”Execution as a result of that. it does not contain a flat, insulating intermediate layer provided with openings at the intersections. To the Insulation of the conductors lying on top of each other in two levels and The conductor pieces are used to define a defined distance between the bare conductors at the crossing points when switching points are open Provide insulating spacers between the crossing points and the ends of the conductors that extend into extend near the crossing points and which are produced by a chemical precipitation process. Through this insulating Spacers that can be produced in a very short length,

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it is possible to have a large "switching point density per unit area to achieve. The height of the spacers also determines the Distance between the base layer and the membrane ο

An expedient further development of the membrane holding device according to the invention is that the base layer and the membrane consist of transparent materials to which the narrow electrical copper conductors are to be applied according to a known corsetry process. With such a transparent Mexnbran switching device which has a low Hur © Dieke, the conductors and the insulating Abstandsottteke and Unlock, sharing, visible in the form of a translucent sitters. This transparency of the membrane switchgear according to the invention brings various advantages, for example the zn actuating® switch parts are easy to find and can be actuated in a targeted manner? or the membrane switching device can be arranged in front of a display panel, in front of a panel or in front of a screen and the switches displayed by these display devices can be recognized by an operator through the membrane switching device.

Further details about the membrane switching device according to the invention, its advantages, features and application are provided in the following in a preferred Äusfülirungsbelepiel based on drawings, Figs. 1 to 3, described in more detail. From the drawings represent:

Fig. 1 is a view of a section through a part

The membrane switch is just about their principle

to recognize.

Fig. 2 'In very start ψφ * ·, _:: % & B <& xtez Image a section, from the © iss «part of the membrane switchgear *

Fig. 3 is an illustration of the basic arrangement of egg ner Membransctialteinrichtung in combination with 009849/1360

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■■■■ - 5 -

a graphic display device.

From Fig. 1 it can be seen that the membrane switch according to the invention, which have a plurality of contact points can contain a flat, sheetlike base layer 10 at the bottom and a flat membrane 12 at the top. The illustration shown in FIG. 1 is a view of a section through the membrane switching device ,, which runs transversely to the plane of the base layer 10 and the membrane 12. The membrane 12 consists of a transparent, elastically deformable material, e.g. B. polyester and the base layer 10 consists of a solid and dimensionally stable Material e.g. B. glass or the like. In those cases, however, where If a flexible circuit structure is appropriate, the base layer 10 can also consist of a polyester material.

On the top of the base layer 10, a number of electrical conductors 14 are arranged _f which are parallel and spaced apart from one another. Such a conductor 14 is shown in FIG. These electrical conductors 14, which can be made of copper, are created and attached as elongated tracks on the base layer 10 by one of the numerous known methods, e.g. B. by a deposition or etching process using stencil masks. Likewise, the underside of the membrane 12 is also provided with such electrical lines 16 and 18, which, however, run in their longitudinal direction transversely to the longitudinal direction of the conductors 14 on the base layer 10.

It is a particular feature of the invention that the membrane 12 and the base layer 10 are spaced apart from one another without a special intermediate layer determining the spacing is required. The electrical conductors 14, 16, 18 on the base layer and the membrane 12 also have a small spacing to each other / and they are electrically isolated from each other by a grown insulating layer on the conductors 14, 16, 18 generated by an electrochemical failure process became. With the exception of the switching points, conductors 14,

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16, 18 covered over their entire length with this insulating layer, that is, the superimposed conductors 14, 16 _f 18 are bare at the points where they cross, because these points form the contact points when the membrane switchgear is actuated by a conductor of the membrane 12 is pressed onto a conductor of the base layer 10. In FIG. 1, the conductor 14 arranged on the base layer 10 is provided with the insulating spacers 20A, 20B and 20C, a switching point being located between each of the two insulating spacers. In the space between two insulating spacers, the conductor 14 is bare. In a manner similar to the conductor 14, the electrical conductors 16 and 18, which are arranged on the membrane 12, are also provided with insulating spacers 21 and 22. The conductors 16 and 18 are also bare at the contact points where they cross the underlying lines of the base layer 10 over a very short length. However, this arrangement is not clear from FIG.

2 shows, in this greatly enlarged illustration, a section of the membrane 12 and an insight into the interior of the membrane switching device, with two crossing conductors 14, 16 which form a switching point. By removing part of the membrane 12, FIG. 2 clearly shows the conductor 14 arranged on the base layer 10 and the conductor 16 crossing it and overlying it, as well as the insulating spacers 20A, 20B _r 21A, 21B which the two conductors 14, 16 asymmetrically surrounded outside the switching point. The lower conductor 14 arranged on the base layer 10 is provided outside the switching point with the insulating spacers 20A and 20B, and the conductor 16 above, which is fastened to the underside of the membrane 12, has the two insulating spacers 21A and 21A outside the switching point 21B on. As can be appreciated from FIG. 2 ma _"r is the distance between dea beidea intersecting conductors 14 and 16 determines etarefa the thickness of this insulating spacers (2OA, 2QB ,, 21AP 21B). A S @ h @ it connection or an electrical contact connection between the two Lei ™

009849/1360

tern 14 and 16 is made in that the membrane 12 to the point above the line crossing using a stylus, Finger or the like. Slightly pressed; by the deflection the membrane 12 is also the conductor 16 at this point downwards deflected and comes into physical contact with the one below Conductor 14, whereby the circuit is completed, Ea is known that when in a plane or in a layer one Switch N-conductor are provided, and assigned in the other Level or layer of this switch M-conductor, that then a matrix switch, also known as a crossbar distributor, is created, which has N · M switching points for connecting unequal pairs of electrical conductors. These conductors are depending on the requirements at hand connected to power sources, or the inputs or outputs of other circuit arrangements, and depending on which Point of the membrane 12 is actuated, the circuit assigned to this point closes. Compared to the well-known Memhrasi switches the membrane switching device according to the invention has various advantages which are explained below. The insulating spacing ücke 2OA, 2OB, 21, 22, etc. are only slightly wider than that electrical conductors 14, 16 ... their width x. B. 0.13 mn (5 mils) can be. Because the insulating spacers are made by an electrophoresis Precipitation processes are generated, a precise control of their thickness and the other dimensions is possible and very good dimensional accuracy is achieved. On the base layer 10 and, the Meabran 12 can thus the conductors 14, 16, 18 be arranged side by side in a very high density, with the result that in the membrane holding device according to the invention on a specific area a very large number of Switching points can be formed.

It is also essential that in the membrane switching device according to the invention no special perforated intermediate layer is required as an insulating layer and as a spacer, and that the insulating spacers 20A, 20B, 21A, 21B, which surround the conductors asypsMitrlsch, are only slightly wider than the electrical ones Ladder, 14, 16, 18, which can be very narrow, as before

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was mentioned standing. The base layer 10 and the membrane 12 can therefore advantageously be made of transparent materials. The electrical conductors 14 , 1%, 18 and the surrounding insulating connection pieces 2QA, 2QB ,, 21A, 21B -... are thus visible as hairlines in the tabletted Merabraa switching device and appear as a grid with a flat switch design, which is easy to eat due to the transparent B & gissehicht 10 and transparent membrane 12.

Fig. 3 shows the connection seaf of such a transparent one. Membrane-SclitilteinrichtUHg to ESosafoiaatio »" with the screen 28 of a display device 26 _y where all tranijpiiresste Mesnbr © n © ehalt »device in front of a screen 28 is assgeQMraet ο B @ l © ptisehea display devices 2 <B _f z _a B ₀ BiMsehlaagsgitesSi ®s worth seeing ^ the Änseige qüqe 0arist © llissig aureh the dates or StriehseichnusagGsa k @ ss & g & ®g®m ^ u isönn © a ₀ This is possible, for example, through the FesucMtelisag voa sasit ^ lichea / e sch devices, the söfemaiateti Isicfet handles ₀ DsCTrtlgts Äaoräawngea ^ oa light pen systems are used for display screen devices, as explained in the OS Pateatsehrifteja 3 337 8SO rand 3 106 707.

In the Fig. 3 EIA ne plane erfindungsgetaäSe Mestoranzeigegerät is combined display system 26 & © n rhaltea "The illustrative Blldseliisiferät, or eiaen BlMsoMsa is lustriert other similar fanQgattwa 2 S which graphisehe DarsfeGltojaf ÜBS

illustrated, in which eimit an. © lektffo-aieehaisch controlled 2β, the ζ «Β“ -ein prnktabtaster BSW « lt how is Fig. 3 il

Äusföfermig aaefe

Fig. 2 is on the ¥ @ Μ © 2 ^> σ © ϋ, & Θ «So © Bi that the horizontal ·?> Ä ©! Iafe? 35ä§ 'siefe braissehalteinricitteafi S @ ait ier lends distraction tibereinstiES ^ sa _c Di © facility 30 stoä.lra sojLetesa

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the tiörlsontalea criminal leader äes M ^ aBbraneehalt * positioned, - that himself

a correspondence with the temporal deflection of the horizontal Deflection signal results, z. B. an even number assignment (mm / see), or in other words, between the line grid of the membrane switch 30 and the deflection system of the picture tube and there is an adapted relationship to the assigned grid points on the screen 28. The X-Y coordinates on the screen 28, certain switching steles of the membrane switching device 30 are assigned in each case. Since the right in front of the screen 28 arranged membrane switching device 30 is transparent, is also the curve generated by the electron beam on the screen Visible to a viewer through the membrane switching device 30, only at the ones formed by the very narrow conductors 14, 16, 18 Grid lines in the membrane switching device 30 there is a barely discernible interruption of the display, but this is generally negligible since the conductor grid lines are very narrow in relation to the thickness of the recording track. In the Cases where the surface of the screen 28 is not flat, but rather is somewhat curved, is used to avoid distortions of the displayed To avoid representations in the membrane switchgear a flexible base layer 10, the z. B. consist of polyester can.

In order to be able to act on the visual display system, the viewer chooses one or more positions on the screen 28. which can be selected by the X / Y coordinates and press with one blunt tip of a pen on the corresponding visible X / Y grid positions of the membrane 12 of the membrane switching device 30. By only slightly pressing in the membrane 12 on the The grid point determined by the X-Y coordinates is the one below Switching element closed by one in the horizontal and one in the vertical direction extending conductor 14, .16 is formed and thus also closes the connected Circuit of the circuit arrangement. The horizontal (X) conductors and the vertical (Y) conductors of the membrane switch 30 and the X / Y deflection system of the visual display device 26 are through intermediaries Circuit devices so coordinated

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and adapted to achieve that at every switch actuated of the membrane switching device 30, the electron beam to the position on the screen 28 assigned to this switching point is deflected.

As has already been explained, in the membrane switching device according to the invention the conductors extending in the horizontal and vertical directions, arranged in a very high density so that there are very many switching points, this has the advantage that the resolution of the graphic Input station is very large (see Fig. 3).

Another example is used below to explain how an operator can generate a desired pattern of a display on a screen 28 in combination with a membrane switching device 30 according to the invention. The horizontal and vertical conductors of a Mesibranschalteinrichtuiig 30 are each part of their connection by plug-in coupling © !! 32 and 34 are connected to further corresponding lines which, when combined, form the cables 36 and 38 and which lead to a memory 40. In the memory 40 every possible switching point of the membrane switch device 30 can be stored, which is formed by a contact closure of a crossing point between a horizontal and vertical conductor Γ4, 16. Once the switching points have been closed and stored, they are available as signals assigned to the XY coordinates of the screen 28 at the output of the memory * 40. These XY coordinate signals corresponding to each switching point of the membrane switching device 30, which are made available at the output of the memory 40, are converted into control signals for the deflection system of the electron beam in an iron digital / analog converter 42 so that the electron beam in the sleeve device 26 is directed to the sonaltutelle © sd & © te X / Y position on the screen 28 is directed. It has already been

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202A98A

thinks that by closing a switching point in the membrane switching device 30 a releasable electrical contact connection between a horizontal land and a vertical electrical conductor will be produced. Each vertical conductor of the membrane switch device 30 is in each case via the multi-core cable 36 in the memory 40 connected to a transistor, which in turn is connected to a voltage source. The horizontal conductors of the membrane switchgear 30 are also connected via a multi-core cable in the memory 40 to transistors / which are at ground potential lie. By actuating a switching point of the membrane switching device 30 a circuit is thus closed, and the transistors of this circuit are activated. The output signals of this activated transistor pair are .representative for the address of the actuated switching point, and they cause the electron beam via the digital / analog converter 42 in the display device 26 on the position of the actuated »Sehalt» place is managed. Because this üacfaführsvate »very sensitive and practically inertia is »know the operator -a» Actuating pin swiftly over the surface of the membrane switch. direction 30 lead, whereby the darentairliegsadem and very Close switching points that are close together one after the other? practically at the same time are at the output of the memory 40 the signals assigned to the corresponding X-Y coordinates are available for further processing and these output signals are also used the electron beam to the corresponding position in Screen 28 tracked. Through the drafty B «fü @ jmg of an actuating pin Via the surface of the membrane 12, the operator can draw any figure at the same time optically by the electron beam on the screen 28 of the display device 26 is shown. Since this manually recorded and optically displayed on the screen 28 figure from individual If there is grid points, the ones assigned to these grid points are available X / Y coordinate signals lsi in digital form at the output of the memory 40 and in analog form at the output of the digital / analog converter 42 for further processing also for other purposes.

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Another possible application of the membrane switch device according to the invention consists in the case when an independent one Input device z. B. a computer a representation on the screen 28 of a display device 26 is generated. In this In this case, part of the display shown can be selected by the operator with the aid of the membrane switching device. Such an application is given, for example, when in a teaching program from the computer on the screen 28 of the display device 26 several questions or answers are displayed, from which the student should choose the correct one by asking the The switch assigned to a question or answer actuated. The position signals ultimately generated by this closed switch, which reach the computer, can then be activated by the computer decide whether the answer given by the student was correct or not.

As already mentioned, FIG. 3 shows the combination of a display device 26 with a membrane switching device 30 according to the invention in the embodiment according to FIGS. 1 and 2, the membrane holding device being arranged directly in front of the screen 28. In the various possible applications in which the membrane switching device according to the invention frequently or continuously interacts with a screen 28 of a cathode ray tube, it is expedient to design the screen surface as a base 10 for the membrane-holding device so that the screen surface has a double function and serves to display the electron beam recording and at the same time serves as a transparent base layer 10 for the membrane switching device 30. For example, the lower conductors 14 belonging to the base layer 10 can be attached directly to the surface of the screen 28. This Jtassüsöäag the conductor 14 directly on the screen 28 has the precaution _; , Dal the width of the specific deflection of the electron beam (z. B. V / mm or the like.) Thus, the grid to the grid width of the calibration intersecting conductors 14, 16 in the membrane switch means predictable 1st w ä same in the fabrication of the picture tube adapted can be. Another advantage

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because of this direct arrangement of the conductors on the screen 28, that the parallax is reduced in the visual display and thus a better representation is achieved.

Of course, it is also possible to use the membrane scarf according to the invention t device except in combination with a display device 26 or with a scanning tube this can also be used for other purposes. As the membrane switching device has a simple, uniform construction which has a more or less large number of compactly arranged switching elements may contain a very large number of which on a unit area can be accommodated, it is possible to have different To create switching combinations, through the respective conductor routing and the arrangement of the insulating spacers. That's the way it is z. B. possible that when a switching point is operated, several contact points close at the same time.

Another application example of such a membrane switching device with a number of very densely arranged switching points is suitable for example as an electromechanical reader Identification of credit cards or ID cards in which the characters or other markings are embossed are incorporated. The high packing density of the switching points results in a good resolution for the identification such key characters.

Depending on the present needs of the arrangement of in its longitudinal direction intersecting conductor 14 shown in Fig. 2 can, 16 and their distance insulation 2OA, 20B ₁ 21A, 21B be modified and adapted to the respective conditions. For example, it is also possible to design the base layer IQ and the membrane 12 to be cylindrical, instead of as flat disks as in FIG. 2, in order to create a cylindrical switching device which, if necessary, can also be rotatable.

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Claims (14)

PATENT CLAIMS 1. Pressure-sensitive membrane switching device with at least an electrical conductor fastened to an insulating base layer and at least one at a short distance above it on the underside of an insulating, elastomeric membrane arranged electrical conductor, its direction intersects with the conductor on the base layer, characterized in that the conductors (14, 16, 18) except the intersections forming a switching point with their distance from each other determining the electrically insulating Material are surrounded. 2. Membrane switching device according to claim 1, characterized in that that the base layer (10) and the membrane (12) are transparent. 3. Membrane switching device according to one of claims 1 or 2, characterized in that to form a switch matrix on the base layer (10) and the underside of the membrane (12) in each case a number of parallel with a certain Distance between adjacent conductors (14, 16) arranged are that the conductors (14) on the base layer cross with the conductors (16) of the membrane in their direction and that the conductor pieces outside the crossing points are provided with insulating spacers (20A, 20B, 21A, 21B). 4. membrane switching device according to one of claims 1 to 3, characterized in that the membrane (12) made of elastomeric Polyester and the base layer (10) consists of a solid and dimensionally stable material (e.g. glass) » 5. membrane switching device according to one of claims 1 to 3, characterized in that the base layer (10) consists of a 009 8 4 9/1360 Docket YO 9-69-017 - 1.5 -.
flexible, pliable material (ζ *. Β. polyester). 6. membrane switching device according to one of claims 1 to 5, characterized in that the conductors (14, 16) on the The base layer and the membrane are deposited copper tracks. 7. membrane switching device according to one of claims 1 or 3, characterized in that the insulating spacers (20A, 20B, 21A, 21B) have a height such that they determine the distance between the base layer (10) and the membrane (12). 8. membrane switching device according to one of claims 1 to 7, characterized in that the insulating spacers (2OA, 2OB, 2IA, 21B) are only slightly wider than the conductors are. 9. membrane switching device according to one of claims 1 to 8, characterized in that the insulating spacers (2QA, 2OB, 21A, 21B) surround the conductors (14, 16) asymmetrically in cross section. 10. Membrane switching device according to one of claims 1,3 or 7 to 9, characterized in that the insulating spacers on the conductors by a chemical precipitation process are formed. 11. Membrane switching device according to one of claims 1 to 9, characterized in that they are on the display area a display device (26) is arranged so that its display panel is completely or partially covered with switching points is. 12. Membrane switching device according to one of claims 1 to 4 or 6 to 10, characterized in that the base layer (10) through the surface of a screen (28) in one 009849/1360 Docket YO 9-69-017 - 16 - Visual display device (26) is formed on which the associated Head (14) are attached. 13. Membrane switching device according to one of claims 11 or 12, characterized in that the distances between the parallel conductors (14/16) to each other in horizontal and vertical direction are adapted to the grid of the screen in the display device (26), and that through the ladder ■ formed grid pattern is congruent with the grid of the display device. 14. Membrane switching device according to one of claims 1 to 13, characterized in that the connection points of the conductors (14, 16) with the beam deflection of an electron beam visual display device (26) influencing electrical circuit devices (40, 42) are connected. 009849/1380 Docket YO 9-69-017 Blank page