DE2900633A1 - FLEXIBLE SWITCH - Google Patents

Description

Dr. Dieter ν. Bezold Dipl.-Ing. Peter Schütz

⁴⁷ ° Dipl.-Ing. Wolfgang Heusler

8 Munich 86, P.O. Box 860668

W. H. BRADY CO.,

727 West Glendale Avenue, Milwaukee, Wisconsin 53201 UNITED STATES.

Flexible push button switch

909830/0634

- 5 flexible push button switches

The invention relates to a flexible push button switch ( ³ touch switches

counter). Often one would like to have a self-luminous effect with such / " have, either to be able to display which switch has been operated, or to continuously identify the individual pushbutton switch positions to display. In known, self-illuminating push-button switches, zones were made to light up next to the actual pushbutton switches are, which was necessary because the contacts underneath the pushbuttons are not translucent was. Instead of the known options, however, the aim is to light up the middle of the switch buttons to bring both the actual touch point better recognizable and the operator an improved one To give an indication of which key he has pressed.

U.S. Patents 3,732,389 and 3,777,222 describe a key switch panel in which the conductors (gold or Tin oxide) are attached to one or two transparent flexible layers (Mylar), which by means of a transparent Spacer layer (Mylar) are kept separate from each other. Light-emitting diodes in a substrate near the area of electrical contact then generate through the transparent ones Layers of light displays.

The invention is based on the object of further improving the illuminated display of the pushbutton switch, making it brighter and in particular to clearly display the center of the button surface immediately.

Thus, according to one aspect of the invention, there is the luminous display the central areas of the individual pushbutton switches are improved by the fact that in the contacts that are on transparent Faces sit, holes are made. In another aspect, transparent adhesives are used to seal the to connect transparent layers of the flexible, self-illuminating pushbutton switch with one another. After another

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Another point of view is a flexible pushbutton switch covered with a layer which is provided with openings, the centers of which are located immediately above the contacts that are held by at least one underlying layer of the Switch are worn, while a continuous, flexible outer layer over the layer provided with openings is spread, the openings are sufficiently smaller so that the individual pushbutton switches are incident in the middle Tactile forces are transferred to the contacts and the tactile feeling is improved.

In a preferred embodiment, two flexible layers have aligned contacts on top of each other facing surfaces and thus form an X-Y matrix (rectangular matrix) , and a spacer layer, the openings of which are aligned with holes in the contacts, separates the two contact-bearing ones Layers of each other. Another layer with openings that are of the same size and are arranged in the same way Holes, related to the contacts, covers the upper contact carrier layer, and a continuous cover layer, which is printed on the underside with translucent color areas on the individual pushbutton switches, covers the further layer provided with openings, so that light from a continuously luminous light source underneath of the switch passes through the two openings and through the two holes in the opposing contacts.

The invention is explained in detail below on the basis of an exemplary embodiment shown in the drawing. Show it:

Fig. 1 is an exploded perspective view of the pushbutton switch, of which the better representation half of the individual parts have broken off;

FIG. 2 shows a partial section through the arrangement according to FIG. 1 in the central plane through the connection lugs (layer thickness shown exaggerated); and

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3 shows a partial section through the layer arrangement of the switch at the location of a pair of transition contact blades, which are connected to each other by a conductive epoxy insert.

Fig. 1 shows in its entirety a panel 10 with flexible pushbutton switches for telephone dialing. Table 10 or the keypad consists essentially of five transparent flexible layers glued together, a cover layer 12, a distributor layer 14, an upper contact carrier layer 16, a spacer or spacer layer 18 and one lower contact carrier layer 20. Flexible flags that connect with the upper contact carrier layer 16 are formed in one piece, are passed down through slots 24, 26 in the spacer layer 18 and the lower contact carrier layer 20. An insert 28 closes the one created in the upper contact carrier layer 16 by the downward bending of the tabs 22 Gap. Below the panel 10 a (not shown) illuminating light source is attached, which the self-luminous effect the individual push button produces. A frame, also not shown, supports the entire panel 10.

The cover layer 12 is a 0.25 mm thick, flexible and non-conductive layer of a polycarbonate film of the type 8BO5 from General Elextric Lexan (with a velvety surface) formed in the ink 112 and has on its underside translucent zones of printing ink 36, 38 and opaque Black and gray areas of ink 35 and 40. These are colors based on acrylic from System II from KC Coatings, Incorporated, Kansas City, Missouri, which are applied by screen printing. The inks layers result in a black main surface background 35, gray pushbutton areas 40 and white, translucent areas Displays 36, 38 including button borders and digits and characters in the center of the button. That from Light emitted by the light source shines through the transparent displays 36, 38.

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By a distance from the cover layer 12 to the upper contact carrier layer 16 to produce, a distribution layer 14 is glued between these two layers, which consists of a 0.075mm thick clear Mylar sheet (trademark from DuPont) is formed from polyethylene terephthalate 41, one on both surfaces after introduction transparent and pressure-sensitive acrylic adhesive layer 42 thermally cured between the two layers 12 and 16, wearing. The two adhesive layers are each 0.04 mm thick. An adhesive suitable for this purpose is that of the 3M Company offered pressure-sensitive acrylic adhesive No. 467. The distribution layer 14 is stamped so that there are openings 46 of about 6.5 7.5 mm directly below each probe area having. The displays 36, 38 are in any case located within the opening borders 46.

The upper contact carrier layer 16 (a 0.13 mm thick transparent Mylar layer) is on its underside with three columns of four 0.018 mm thick, consisting of conductive ink contacts 48 are printed. The conductive Printing ink comes from Acheson Colloids, Port Huron, Michigan and has the designation Electrodag 415SS. The contacts 48 are connected to conductors 50 which continue to the contact lugs 22. Each contact 48 is in the shape of one Rectangle, the rectangular central zone of which is missing, so that light passes through this open and therefore transparent center 52 can pass through. The size of the contacts is approximately 14x16 mm, their transparent centers 6.5 χ 7.5 mm, which is the Corresponds to the size of the openings 46 in the distribution layer.

Extends from a peripheral edge of the upper conductor layer 16 the flag 22 downwards. Two cuts 54 of about 6.5 mm in length are made from the edge into the layer with the upper conductors cut so that the flag end 22 can be bent downward within the perimeter of the panel 10. The end of the flag carries conductors 50 connected to contacts 48 of upper conductor support layer 16 and leads 56 of FIG transfer plates 58, which are located near the bending point of the

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End of the flag are arranged. The transfer leaflets 58 are with other transfer papers 59 and with these connected conductors 60 on the lower conductor support layer 20 via uncured, conductive epoxy inserts 62 in the spacer layer 18 connected. The conductive epoxy inserts are made from an epoxy resin that does not mix with a Is mixed harder, but with silver particles mixed in. The epoxy resin comes from Amicon, Lexington, Massachusetts and operates under the trade name Uniset, Type C-14. All conductors and transfer papers are under Manufactured using the same conductive ink that was used to make contacts 48. The terminal lug strip 22 carries seven conductors, one for each column of the upper contact carrier layer 16 and one for each contact row of the lower contact carrier layer 20 »by the downward bending of the contact lugs 22 within of the perimeter edge of the push-button panel 10, the conductors 50 and 56 with a circuit (not shown) below of the support frame, not shown, and then the push button panel or plate on the frame along its be sealed over the entire edge. The insert 28, which is also made of the 0.13 mm thick, transparent Mylar layer of the upper contact carrier plate 16 is made, fits exactly into the gap between the cutting lines 54.

The upper contact carrier layer 16 and the lower contact carrier layer 20 are separated from one another by the spacer layer 18 glued in between. In the structure of the distribution layer 14 the same, the spacer layer 18 consists of a 0.075 mm thick Mylar film 64 between two 0.04 mm thick adhesive layers 66 and 68. Rectangular holes 70 in the spacer layer are punched below the contacts 48. These Holes 70 are larger than the openings 46 'of the distributor layer 14 and slightly smaller than the contacts 48 and 74, which can be seen in FIG. A slot 24 leaves the terminal lugs 22 step through. On both sides of the slot 24 four round holes 72 are arranged for receiving the non-cured conductive epoxy resin 62, which when

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build transfer sheets 58 and 59 together into conductive ones Connection. The holes 72 have a diameter of 6.5 mm.

The lower contact carrier layer 20 made of 0.13 mm thick Transparent Mylar carries the contacts 74, the conductor connections, printed on with conductive printing ink 60 and the transfer sheets 59 and, on their underside, an adhesive layer 73 of the type already described above from the 3M company. The contacts 74 are connected to the transfer plates 59 by means of extensions of the conductors 60. The contacts 74 are aligned with the contacts 48 of the upper contact carrier layer 16 and have the same rectangular shape Shape with the rectangular, transparent central openings 76. A slot 26 receives the contact lugs 22. One Adhesive layer 73 bonds the entire pushbutton panel or plate 10 to the support frame, which is not shown.

When the individual pushbutton switches are actuated, the finger essentially depresses the center of the pushbutton surface marked by the boundary lines. The one from the Force exerted by the fingertip is transferred at the distributor layer to the edge of the associated opening 46 (FIG. 2). from At this edge, the force has a direct effect on the rectangular contact ring 48 and ensures contact is made between the contacts 48 and 74. If the distributor layer is missing, the force exerted in the middle by the fingertip could be not be strong enough to press against the contact edge with sufficient force and thus make contact with the To generate mating contact. When contacts 48 and 74 touch, a circuit is created between a line of conductors 60 on the lower contact carrier plate 20 and a conductor column 50 of the upper contact carrier plate 16 are closed. The layers 16 and 20 thus represent an X-Y matrix. The circuit is completed via the non-hardened conductive Epoxy resin 62, which is a pair of the corresponding transfer flakes 58, 59 connects to each other. The illumination light source illuminates the touch surface borders 36

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and the displays 38 arranged in the middle therein, so that the individual buttons can be seen in the dark. That Light passes through the transparent centers 76 of the lower contact carrier layer 20, the holes 70 of the spacer layer, the transparent centers 52 of the upper contact carrier layer 16, the openings 46 in the distributor layer 14 and the translucent displays 36, 38 in the cover layer 12.

It is not essential that contacts 48 and 74 be arranged in an X-Y matrix. It could For example, one contact in the pattern of two spaced-apart circuit paths and the other as an electrical bridging element be designed with which the circuit is closed between the circuit paths. The corresponding conductive patterns could be applied to a surface of the substrate or frame on which the flexible switch is attached. The spacer layer 18 need not be included in the flexible circuit board either but can be built into the surface of the support frame, which also applies to the adhesive with which the switch panel is attached. Adjacent openings 46, 70 can be connected to one another through air ducts, as a result of which the sense of touch is further improved.

Establishing the electrical contacts between the circuits of the spaced apart layers of the flexible push button switch using a non-compressed, pressure insensitive conductive material that is located in the openings of the spacer layer is not the subject of the present invention Invention. Also the connection of the conductors from the contacts of the contact-bearing layers with other circuit parts using the flexible tabs as well as the advantage of bending the tabs down from the top layer through Slits in the underlying layers are not to be dealt with in more detail in connection with the present invention will.

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Claims (14)

PATENT CLAIMS 1. \ Flexible push button switch, marked by "a transparent, flexible plastic layer (16), the one Contact zone (48) carries, and a layer of transparent adhesive that adheres to the plastic layer (16) and with the Plastic layer cooperates in such a way that light from an underlying light source passes through the layers to the top got. 2. Push button switch according to claim 1, characterized in that that the flexible plastic layer (16) carries a plurality of contact zones (48) and that in the surface areas between the contact zones (48) is a patterned layer of an opaque color. 3. Push button switch according to claim 2, characterized in that that the opaque paint layer is from a transparent layer arranged over the flexible plastic layer (16) Layer (12) is worn. 4. Push button switch according to claim 2, characterized in that that side by side with the patterned opaque paint layer zones of translucent color as luminous markings of displays and transparent zones for the display of the switch operating status are provided. 5. Push button switch according to claim 1, characterized in that that the transparent flexible plastic layer (16) on its underside a plurality of spaced apart Contact zones (48) and that a second transparent flexible plastic layer (20) in the stack under the first flexible plastic layer is arranged, on its side facing the first flexible plastic layer (16) Carries a plurality of contact zones (74) and the other side of which has a layer of a transparent adhesive. 909830/0634 6. Flexible push button switch, characterized by a flexible plastic layer (16) with a contact zone which a transparent area (52) for light from an underlying light source, the light being transparent Area (52) of the contact zone and the flexible layer (16) penetrates. 7. Push button switch according to claim 6, characterized in that the flexible plastic layer is transparent. 8. Push button switch according to claim 6, characterized in that a with the flexible plastic layer transparent area is provided in the contact zone aligned hole. 9. Push button switch according to claim 7, characterized in that that the transparent area of the contact zone through a flexible plastic layer carrying the contact zone exposing hole is formed. 10. Push button switch according to claim 9, characterized in that the contact zone as a ring with transparent Central region (250) is formed. 11. Push button switch according to claim 9, characterized in that the contact zone is rectangular and the transparent one Area formed therein as a rectangular opening is. 12. Push button switch according to claim 6, characterized by a second flexible plastic layer (20) with a second contact zone (74) which is aligned with the first contact zone (48) and a transparent area (76) which is aligned with the transparent area (52) in the first contact zone (48), and a spacer layer (18) with openings between the flexible plastic layers that are aligned with the contact zones (48, 74) (16,20), so that the light from a light source arranged underneath passes through the "plastic layers (16,20) and the standing layer (18) passes through. « 13. Push button switch according to claim 12, characterized in that that the flexible plastic layers (16, 20) with a plurality of mutually aligned and one another pointing contact zones (48,74) are occupied and the spacer layer (18) has a plurality of contact zones (48,74) has aligned openings (70), the contact zones being arranged in an X-Y matrix switch arrangement are. 14. Flexible push button switch, characterized by a flexible plastic layer (16), which has a contact zone (48) carries a second layer (14) over the plastic layer (16) and a cover layer (12) over the second Layer (14), the second layer (14) having an opening, the center of which is arranged above the contact zone (48) is, whereby tactile contact forces are transmitted from the center of the opening (46) to the contact zone (48). 09830/0634