EP3018681A1 - Flexible switching mat and its use - Google Patents

Abstract

Silicone switching mat (1) for at least partially covering a printed circuit board (3), wherein the silicone switching mat (1) at least one key (1e, 1f, 4, 4a) with tactile feedback for generating a contact on the printed circuit board (3), characterized in that the silicone switching mat (1) has a cover region (8) of a low-grade elastomer having at least one receiving region (4a) and at least one inserting region (4) made of a high-quality elastomer used in the receiving region (4a).

Description

TECHNICAL AREA

The present invention relates to a silicone switching mat, in particular for use as a switch component in the automotive sector. Furthermore, the present invention relates to a method for producing such a silicone switching mat and uses of such a silicone switching mat.

STATE OF THE ART

Silicone keypads are often used in automobile keys and switches to provide tactile feedback and to close the electrical contact. In addition, the switching mat often takes on a sealing function on the circuit board and has integrated light wells to prevent light leakage of the backlighting of the keys.

The demands from the customers steady steadily in terms of life cycles, tolerances and tactile effect while decreasing prices.

Silicone mats are application specific parts and are redesigned and designed for each switch. Today's technology no longer meets the requirements or is too expensive.

The solutions known today in this connection are, in particular, silicone switching mats made of solid silicone in the compression process or silicone switching mats made of liquid silicone by injection molding.

The advantages of solid silicone silicone mats in the compression process are the low cost of the press tools and the flexible manufacturing process. Solid silicone is available in different grades, but solid silicones have a large hysteresis, which has a negative effect on the life cycles. There is no high-grade solid silicone with a high Shore hardness, but this would be necessary for switching mats with a short stroke <1.2 mm to get a good tactile feedback and a high number of switching cycles. Since the pressing process is a manual process, many mistakes are made, which leads to rejects and complaints. Also, a vulcanization cycle in the press is about 5-10 minutes.

In the production of silicone liquid silicone mats by injection molding The tools are approx. factor 3 to 10 more expensive than with silicone switching mats made of solid silicone in the compression method. With liquid silicone, there are better life cycles, the automated process allows much tighter production tolerances to be realized, and rejects and errors are much lower. Liquid silicone is also available with 80 Shore in a very good quality which Kurzhubschaltmatten with strokes of at least 0.5 mm with very good tactile feedback and / or high forces possible. Today only relatively small safety mats, which run in very large numbers, are produced in liquid silicone. The shooting time is about 30 seconds.

From the EP 1662527 Safety mats are known from an elastomeric material, wherein contiguous covers are arranged on the top, and also contiguous so-called keypads are arranged underneath. The tactile feedback is generated by metal domes located below both layers. Material properties for the cover and keypad are not quantified US 2010/0067254 are multi-layered structures on printed circuit boards are known to be provided below the tracks metal dome for generating the tactile feedback, and above each over the entire surface of the circuit board coherently formed layers of different plastic material, in which case no material properties are given.

From the US 4609791 switch elements are known in which a plurality of again cohesively formed key elements are provided for generating a tactile feedback at different locations and for contacting. Arranged above is a housing made of a rigid material. No material properties are disclosed.

From the EP 0896349 For example, a single switching dome is known which has a plurality of layers of different plastic materials on the upper side. Coherent coverage does not disclose this document.

From the US 5114790 is also known embedded in a rigid housing switch, in which a dome of a silicone material is arranged under a rigid push button. No material properties are disclosed.

PRESENTATION OF THE INVENTION

It is accordingly an object of the present invention, a simple and cheaper to manufacture silicone switching mat with good mechanical properties, the Maintained over a long life, and can be adapted to a variety of customer needs without high costs.

This object is achieved according to the invention by a silicone switching mat with the features of claim 1.

Specifically, the present invention relates to a silicone switching mat for at least partially covering a printed circuit board, wherein the silicone switching mat has at least one button with tactile feedback for generating a contact on the circuit board. Typically, such a silicone keypad has several such keys, in which case with multiple keys in the same silicone keypad these keys are not related to tactile feedback, but are separate individual keys made of a high-quality elastomer.

The proposed silicone switching mat is characterized in that it comprises a cover area forming the cover of a low-grade elastomer having at least one receiving area, and at least one inserted in the receiving area insertion of a high-quality elastomer.

A high-quality elastomer of the insert is to be understood as meaning an elastomer having a Shore A hardness of at least 70 and preferably not more than 90, and a tensile strength of at least 300%, preferably of at least 350%. In each case in this application, the Shore hardness is determined according to DIN 53 505 and the tensile strength according to DIN 53 504 S2. The high-quality elastomer is furthermore preferably characterized in that it has a low internal damping. The lifetime of a typical dome is in the range of 100,000-500,000 switching cycles, preferably more than 300,000 switching cycles. With a Shore A hardness of 80, the high quality elastomer preferably has a tear strength of 150%, a typical dome life in the range of 100,000 to 500,000 cycles, preferably more than 300,000 cycles.

By a low-grade elastomer of the cover region is meant a material having a Shore A hardness in the range of 30-80, preferably in the range of 30-60 or of less than 70. Preferably, it has a tensile strength of 70 at a Shore hardness of 70 less than 300%, preferably less than 200%, with the internal damping being high.

The low-grade elastomer of the cover region is preferably a solid silicone.

The high quality elastomer of the insert is preferably a liquid silicone or TPU (thermoplastic polyurethane).

One of the core concepts of the present invention is to selectively produce only those parts of high quality material which actually require the high quality. For the mechanical durability and for the tactile feedback it is sufficient to produce in such a silicone switching mat respectively the insertion of the high-quality material and the rest of the silicone switching mat of a low-grade material. The low-grade material also allows simplified production methods, which are more cost-effective, especially for small series, and accordingly allow adaptation to customer-specific requirements. The on the other hand expensive procedures for the processing of the high-quality material can be used selectively then only for the inserting dome. On the other hand, the insertion dome does not need to be adapted to the customer's requirements to the same extent. However, for different tactile feedbacks, insert geometries of different materials can always be prefabricated with the same geometric dimensions, and then used for a wide variety of custom applications, each with individual coverage areas. This is surprisingly possible to have to accept without a loss compared to the situation in which the whole silicone switching mat is made of the high quality material.

A further preferred embodiment of the proposed silicone switching mat is characterized in that the covering area is formed contiguous, and that the respectively the inserting dome are placed on the side facing the circuit board in receiving areas provided for this purpose and are preferably secured therein positively and / or non-positively and / or materially ,

In such a contiguous coverage area, at least one receiving area can have a bell membrane without tactile feedback and / or elements, in particular in the area of the receiving area arranged parallel to the surface of the printed circuit board, elements, in particular in the form of recesses and / or elevations (for example, one after downwardly directed pin) are arranged, which are provided by engagement in respectively corresponding elevations or depressions (or even passage opening) of the insert, preferably in the deck area, which for positioning and / or attachment of the insert in the Serve recording area.

However, the silicone keypad of the present invention need not be continuous as a whole. Thus, according to an alternative embodiment, it is possible to design the silicone switching mat in such a way that the covering region has at least one receiving opening in the form of a passage opening for the insertion of an insert, preferably for inserting the insert with its foot region, wherein the receiving opening is preferably stepped and / or a groove or a comb, so that the foot region of the insert can be fixed in a form-fitting manner and forming a closed surface of the silicone switching mat in this area, optionally with the additional aid of a bonding agent.

A further preferred embodiment of the proposed silicone switching mat is characterized in that the at least one insert has a preferably circumferential and upwardly projecting from a preferably peripheral foot region cone membrane for the generation of a tactile feedback and a cone cone up in a plane parallel to the circuit board partially or completely concluding deck area, wherein on the circuit board facing the underside of the deck area a contact pill attached and / or embedded and / or injected, preferably based on a metal foam, or a conductive ink is applied.

The insert can also consist of conductive liquid silicone, so that can be completely dispensed with a separate contact pill or a Leitlack.

Such a silicone switching mat can have at least two, preferably at least 3 or more, keys with tactile feedback in the same silicone switching mat, which are formed by inserting inserts made of high-quality elastomer. In addition, such a silicone switching mat can additionally comprise at least one further element from the following list: light shaft, pocket for electronic elements, positioning pins, sealing, etc.

Furthermore, the present invention relates to a method for producing a silicone switching mat, as described above, wherein the method is characterized in particular in that the covering area of the low-grade elastomer separately from the insert or the majority of inserting high-grade elastomer, in particular in a Spray process, is produced, and the Inserted domes inserted into the coverage area and preferably in receiving areas provided therein and / or receiving openings are attached.

Such a method may be characterized in that the coverage area is designed in an application-specific manner and the insertion diameters are manufactured as a standard component.

Moreover, the present invention relates to the use of a silicone switching mat as described above as switches in the automotive sector or in the field of mobile technology, telecommunications technology, in the field of portable computers, etc.

• Die anwendungsspezifische Schaltmatte wird aus einem kostengünstigen Elastomer hergestellt. Dieses Elastomer kann ein Festsilikon sein in der Härte 30-80° Shore A oder ein thermoplastisches Elastomer (TPE). Bevorzugt wird ein Festsilikon mit 60-70° Shore A.

In summary, the following can be stated:

• The application-specific switching mat is made from a low-cost elastomer. This elastomer may be a solid silicone in the hardness 30-80 ° Shore A or a thermoplastic elastomer (TPE). Preferred is a solid silicone with 60-70 ° Shore A.

This safety mat contains optional elements for seals, positioning, light shafts, etc. Instead of domes, only one receptacle for inserting domes is provided in the safety mat. In this recording high-quality insert dome are used. The insert domes are made of a high quality elastomer and have a cone diaphragm that generates the force-displacement curve of the button. The contact pill is no longer inserted in the safety mat, but is attached to the inserting dome. The elastomer for the insert may be a liquid silicone in the hardness of 30-80 ° or 70-90 Shore A or be a TPU or a high-grade solid silicone. Preferred is a liquid silicone in the hardness of 70-80 ° or 70-90 Shore A.

The inserting domes are fastened in the receptacles provided for this purpose in the safety mat. There are different variants for positioning and fixing the insert dome.

A variant consists of a hole in the mats base in which the insert dome is fitted and fixed with adhesive (cf. FIG. 3a ). Optionally, a small flange above may provide mechanical attachment.

Another variant is similar, except that here the dome is mechanically fixed in all directions by means of a joint and a groove (cf. FIG. 3b ).

Preferably, another variant, where the insert is inserted in a closed pocket of the switching mat (see Figure 3c ). This bag is designed so that a bell membrane is created, which participates in the button movement of the button, without the Force-displacement curve adversely affect. Through the bag and the tightness of the safety mat is given.

In the head of the bag can preferably be attached a pin (see 3d figure ), which engages in the key top of the insert dome and achieves good adhesion.

But also an adhesive connection (cf. FIG. 3e ) or a pin on the key top of the insert (compare FIG. 3f ), which engages in the pocket of the safety mat, are possible designs.

As an option to the contact pill in the insert, it is also possible to inject an electrically conductive material in the pill area, for example a liquid silicone with a carbon filler. Instead of a contact pill and the whole Eilegedom can be injected from electrically conductive liquid silicone, thereby eliminating the insertion of a contact pill. Application of conductive ink in the contact area is another way of contacting.

The application-specific safety mat tool is simplified because no more contact pills need to be inserted and the force-displacement curve must be paid no attention. As a result, the shot time at the press can be significantly shortened and there is much less waste. The silicone used does not need to fulfill any mechanical properties and can therefore be reduced with a lot of filler.

The insert domes can be made automatically in a multiple injection mold. The contact pills are placed in the cavities by means of robots and the finished parts are automatically removed. This ensures a consistently high quality. The high-quality liquid silicone is only used where it has to fulfill a function: in the single dome of the safety mat.

In a mounting variant, the key height of the dome can be adjusted to the mounting mat of the installation situation despite standardized Einlegedom by the key top is increased on the recording.

Also, the force-displacement curve on the geometry of the bell membrane and the Shore hardness of the keypad can be easily varied application specific.

The stroke of a key can also be increased by sinking the insert dome deeper into the mounting pocket, then in a first actuation phase only the bell diaphragm comes into play, which can be used to bias the key.

Through different uses in the injection molding tool, different cone-diaphragm geometries can be realized for the insertion dome, without enormous investment in the injection molding tool. The master tool remains and also the loading of the contact pills and removal of the finished dome remains the same.

• Das höherwertige Flüssigsilikon oder TPU ermöglicht höhere Schaltzyklen und ein besseres taktiles Gefühl bei kürzerem Hub als das mit Festsilikonschaltmatten möglich wäre;
• Die Qualität wird durch den vollautomatischen Spritzgiessprozess wesentlich verbessert, die Membrandicke schwankt weniger, die Kontaktpillen werden von Roboter eingelegt, die Härte und Vulkanisation und Einspritzgewicht wird automatisch überwacht;
• Werkzeugkosten für projektspezifische Schaltmatte wird reduziert, es fallen nur einmalig Kosten an für das Spritzgusswerkzeug des Einlegedomes;
• Teilekosten werden reduziert, weil der Volumenanteil des hochwertigen Materials deutlich reduziert wird.

The main advantages can be summarized as follows:

• The higher-quality liquid silicone or TPU allows higher switching cycles and a better tactile feel at a shorter stroke than would be possible with solid silicone switching mats;
• The quality is significantly improved by the fully automatic injection molding process, the membrane thickness fluctuates less, the contact pills are inserted by robots, the hardness and vulcanization and injection weight is automatically monitored;
• Tool costs for project-specific switching mat are reduced, there are only once costs for the injection molding tool of the inserting dome;
• Parts costs are reduced because the volume fraction of the high-quality material is significantly reduced.

• Schaltmatten für Tasten im Automobil wie Fensterheber, Spiegelversteller, Start-Stopp Tasten, Autoradio etc.

As an exemplary application, the following can be stated:

• Safety mats for buttons in automobiles such as window regulators, mirror adjusters, start-stop buttons, car radio etc.

Further embodiments are given in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

in a) ein Kraft-Weg Diagramm für einen Dom mit innerer Dämpfung und in b) eine Silikonschaltmatte nach dem Stand der Technik;

Fig. 2

eine Silikonschaltmatte mit separatem Abdeckungsbereich und in dieser Schnittdarstellung zwei aus einem hochwertigen Elastomer gefertigten Einlegedome;

Fig. 3

Schnittdarstellungen von verschiedenen Anordnungen von Einlegedomen in einem Abdeckungsbereich, wobei in a) die Anordnung eines Einlegedoms in einer gestuften Durchgangsöffnung als Aufnahmebereich im Abdeckungsbereich dargestellt ist, in b) die Anordnung eines Einlegedoms in einer Durchgangsöffnung mit einem umlaufenden Kamm, der in eine umlaufende Nut im Fussbereich des Einlegedoms eingreift, dargestellt ist, in c) die Anordnung eines Einlegedoms in einem zusammenhängenden Abdeckungsbereich ohne spezielle Strukturierung der Glocken-Membrane des Abdeckungsbereichs, in d) eine Glocken-Membrane mit einem nach unten ab stehenden Zapfen zur Positionierung des Einlegedoms dargestellt ist, in e) eine Glocken-Membrane mit einer zentralen Verdickung dargestellt ist und in f) eine Glocken-Membrane in besonders dünner und auf die Kontur des Einlegedoms angepasster Struktur;

Fig. 4

zeigt einen Standard-Dom, wie er für die Bestimmung des Kraft/Wegdiagramms respektive der inneren Dämpfungseigenschaften des entsprechenden Materials eingesetzt wird, wobei in a) eine Ansicht von unten, in b) eine 1. Seitenansicht, in c) eine 2. Seitenansicht, in d) eine Sicht von oben, in e) eine perspektivische Ansicht von schräg oben, in f) eine perspektivische Ansicht von schräg unten und in g) eine zentrale Schnittdarstellung gegeben ist.

Preferred embodiments of the invention will be described below with reference to the drawings, which are given by way of illustration only and are not to be interpreted as limiting. In the drawings show:

Fig. 1

in a) a force-displacement diagram for a dome with internal damping and in b) a silicone switching mat according to the prior art;

Fig. 2

a silicone keypad with a separate cover area and in this sectional view two insert domes made of a high quality elastomer;

Fig. 3

Sectional views of various arrangements of insertion dome in a coverage area, wherein in a) the arrangement of an inserting dome in a stepped through hole as a receiving area in B) the arrangement of an inserting dome in a passage opening with a circumferential ridge which engages in a circumferential groove in the foot region of the inserting dome, c) the arrangement of an inserting dome in a continuous covering area without special structuring of the bells Diaphragm of the cover area, in d) a bell membrane is shown with a downwardly projecting pin for positioning the insert, in e) a bell membrane is shown with a central thickening and in f) a bell membrane in particularly thin and structure adapted to the contour of the insertion point;

Fig. 4

shows a standard dome, as it is used for the determination of the force / path diagram or the internal damping properties of the corresponding material, wherein in a) a view from below, in b) a first side view, in c) a second side view, in d) a view from above, in e) a perspective view obliquely from above, in f) a perspective view obliquely from below and in g) a central sectional view is given.

DESCRIPTION OF PREFERRED EMBODIMENTS

As mentioned above, the high quality elastomer has low internal damping. On the other hand, the low-grade elastomer has a comparatively high internal damping. To explain this in the present context with regard to the relevant properties must first on a force-displacement diagram according to FIG. 1a which represents how a dome behaves. The path is shown on the x-axis and the corresponding force on the y-axis. If a dome is loaded over a path, the counterforce of the dome increases successively up to a maximum value, the tripping force F1. If this triggering force F1 is exceeded at the distance s1, the force decreases, which is experienced by the user as snapping and ensures exactly the relevant tactile feedback of the dome. The force then reaches a minimum value at the position s2 at the contact force F2. Now continue to press on the dome to ensure a secure contact on the circuit board. The upper curve in FIG. 1a represents this triggering.

When the dome is released, the force-displacement diagram follows the lower one Curve. The reason for this is that the restoring force is reduced more rapidly at the discharge than at the initial load, the effect being due to the energy converted into heat by internal friction in the molecular structure. Ultimately, this is a hysteresis. In the feedback, the force at the position s2 correspondingly passes through a lower minimum value than at the initial load, this restoring force F3, compared with the corresponding force F2 during the load, is a measure of the internal damping. High-quality materials have a low internal damping and thus a low hysteresis, considered as the difference between the forces F2 and F3, low-valued materials over a large internal damping and thus a comparatively large hysteresis, ie the difference between the forces F2 and F3 comparatively large.

For the materials of interest in the present application, the values of damping, each measured against such a standard dome for the high-quality elastomer of preferred masses, are such that the force difference expressed by the difference in forces F2 and F3 (F2 minus F3) is typically less than 0.5 N, preferably less than 0.2 N. For the low-grade elastomer, the force difference, expressed by the difference of the forces F2 and F3 (F2 minus F3), is typically greater than 0.5 N, preferably greater than 0.7 N.

FIG. 3 shows such a standard dome in different representations. In order to determine the internal damping of the corresponding material, such a standard dome is produced and the force / travel diagram is determined. For example, to determine if the elastomer is high grade, such a standard dome is made which determines the force / path diagram, and if the difference in forces F2 and F3 (F2 minus F3) is less than 0.5N, then It is a high-quality elastomer, if greater to a low-grade elastomer. The specific dimensioning of this standard dome is, as far as not already shown in the figures, as follows: SMT Silicone Key, key top diameter: 3mm; Contact pill: carbon pill; Key height: 4mm; Stroke (stroke): 1.6mm; Diaphragm angle: 60 °; Membrane thickness: 0.6mm.

In FIG. 1b a silicone switching mat 1 is shown in conventional construction according to the prior art. As can be seen on the basis of this sectional view, a printed circuit board 3, not shown here, a printed circuit board 3 is arranged substantially completely covering silicone area. These are contiguous except for specifically provided openings such as a light well 1d Silicone structure has on both sides depending on a Dom 1a, which is designed as a button with a tactile feedback. The dome 1a has a head which is provided for actuation, and this head is connected via a circumferential cone diaphragm 1b to the actual horizontal region of the switching mat. On the bottom of the head, a contact pill 1c is attached.

The tactile feedback and the contacting is done in this conventional silicone switching mat so that is pressed on the head of the respective button, and against the restoring force of the cone diaphragm 1b then the dome, and in particular arranged on the bottom contact pill 1c on the conductor track. 3 pressed down. Two spaced-apart conductors are arranged on the conductor track in the region of the contact pill, which conductors are brought into conductive contact upon contact of the contact pill with the conductor track.

A disadvantage of such silicone switching mats according to the prior art is that they as a whole, if high-quality requirements are to be met, must be made suitable from a high-quality material for the tactile feedback. This creates high costs and is uncomfortable, especially in the custom customization.

As stated above, the object of the present invention is to propose an improved silicone switching mat in this connection.

In FIG. 2 a silicone switching mat 1 according to the improved construction according to the present invention is shown. On a printed circuit board 3, a cover region 8 is provided here, which is designed to be continuous with, for example, a light shaft 1d with LED 2 arranged underneath. As the name suggests, this cover is only intended to cover and seal and to provide positioning assistance and to define a coherent surface. The tactile feedback of the button and the contact are not guaranteed by this cover.

The cover is made of a relatively low-grade elastomeric material, typically a solid silicone. Accordingly, the cover can be made custom comparatively cheap. However, the cover 8 does not have correspondingly high-quality properties; in particular, if tactile feedbacks are generated from such a material, the corresponding regions could not have high life cycles.

Accordingly, 8 inserting 4 are provided separately from the cover, which now just made of high quality material and make the tactile feedback available. The inserting dome 4 are inserted into corresponding receiving areas, here in the form of bell membranes 1f, the cover. At the in FIG. 2 As shown construction has the bell membrane 1f in the deck area 1e via a downwardly directed pin. This pin engages in a corresponding recess or opening in the deck area 13 of the insert.

In the case of the embodiment according to FIG. 2 this recess is formed in the deck area 13 as a passage opening which is closed downwards only by the contact pill 4b. Through this positive connection between the pin in the bell membrane 1f and the opening or recess in the deck area 13 of the inserting dome 4 results in a positioning and at the same time a mounting option for the insert dome. By appropriate structuring a positive connection can be ensured here (for example, by the outer diameter of the pin is chosen slightly larger than the inner diameter in the recess in the deck area 13), which provides a more extensive fixation, for example by a bonding agent of the insert on the cover.

The insert domes can be fastened in the cover in different ways. Different variants are in FIG. 2 shown, these variants are all slightly different than the ones in FIG. 2 illustrated with a passage opening in the deck area 13 of the insert.

In FIG. 3a a variant is shown, in which the cover 8 has a passage opening as a receiving opening 11 for the corresponding insert. This passage opening of the cover is stepped but formed so that a circumferential notch is formed on the underside, which faces the circuit board. In this stage, the corresponding insert dome can be fitted or pressed with his foot. Again, it is possible to ensure a positive connection for fixing the insert dome. Through this stepped training is also ensured that the silicone switching mat as a whole, that is cover with inserting dome, forms a closed cover.

A variant of this is in FIG. 3b shown. Again, there is a through hole in the cover 8, but this is not only stepped, but the through hole in the coverage area has a circumferential, for Center of the passage-directed ridge. The foot of the corresponding dome has a corresponding radially outwardly open groove, and the insert dome can now be positively locked in positive fit in a groove / comb connection in this passage opening under positive engagement.

Another simple realization is in Figure 3c shown. Here, the bell membrane 1f is provided as a closed bell membrane in the cover. The insert 4 is inserted from below into this somewhat formed depression. Another variant is in 3d figure shown. This variant is similar to the one in FIG. 2 shown, and it is referred to the description there. In the deck area 13 of the insert dome there is no passage opening, but only one recess. In this depression engages a slightly shorter trained pin of the area 1e of the bell membrane. In this case, there is still some room in the depression, this can be used, for example, to introduce a bonding agent in the appropriate pocket in the deck area 13 of the insert dome 4 before introducing the insert dome in the coverage area, then firmly fasten the insert dome. It is also possible to introduce special components in this area.

Yet another variant is in FIG. 3e shown here, the bell membrane 1f of the coverage area has a slight extension upwards to be inserted, for example, in a depression over the whole device related cover. Last but not least is in FIG. 3f a variant is shown where, instead of a downwardly directed pin in the bell membrane 1f to some extent in a kinematic reversal in the bell membrane a recess is formed and in the deck area 13 of the insert dome an upwardly directed pin. Even so, a frictional attachment of a loading dome in the coverage area with good positioning is possible. LIST OF REFERENCE NUMBERS 1 Silicone keypad 7a Pin to switch mat 1 / hole in insert dome 4 1a cathedral 1b Cone diaphragm for tactile feedback 7b Flat with adhesive or undercut in safety mat base 1c Contact pill 1d optional elements such as light shaft, button for electronic elements, positioning pins, etc. 7c Pin to insert sleeve 4 / recording in safety mat 8th Coverage range of 1 low-grade elastomer 1e Recording for inserting dome 9 Thongs on bottom of 1f 1f Bells diaphragm without tactile feedback 10 Well on top of 4 2 LED or electronic components 11 Receiving opening for 4 in 8 3 circuit board 12 Foot area of 4, pedestal 4 Inserted dome made of high-quality liquid silicone or elastomer 13 deck area F1 release force F2 contact force 4a Cone diaphragm for tactile feedback of 4 F3 return force s1 Way to F1, ie release force 4b Contact pill of 4 s2 Way to grab 5 Hole in safety mat with adhesive surface snap grab Force force 6 Hole in safety mat with undercut for mechanical support Stroke path 7 Bag to insert

Claims (15)

Silicone switching mat (1) for at least partially covering a printed circuit board (3), wherein the silicone switching mat (1) at least one key (1e, 1f, 4, 4a) with tactile feedback for generating a contact on the circuit board (3),
characterized in that
the silicone switching mat (1) has a cover region (8) of a low-grade elastomer having at least one receiving area (4a) and at least one inserting area (4a) inserted in the receiving area (4a) for generating the tactile feedback from a high-quality elastomer. Silicone switching mat (1) according to claim 1, characterized in that the high-quality elastomer of the insert (4) has a Shore A hardness of at least 70 and a tensile strength of at least 300%, preferably of at least 350%, further preferably the inner damping low is. Silicone switching mat (1) according to one of the preceding claims, characterized in that the low-grade elastomer of the cover region (8) has a Shore A hardness in the range of 30-80, preferably in the range of less than 70 or 30 to 60, where preferred masses has a tear strength of less than 300%, preferably less than 200%, wherein the internal damping is preferably high. Silicone switching mat (1) according to one of the preceding claims, characterized in that the low-grade elastomer of the cover region (8) is a solid silicone. Silicone switching mat (1) according to one of the preceding claims, characterized in that it is the high-quality elastomer of the insert (4) is a liquid silicone or TPU. Silicone switching mat (1) according to any one of the preceding claims, characterized in that the cover region (8) is formed contiguous, and that the respectively the inserting dome (4) on the printed circuit board (3) facing side in receiving areas provided (1f) are inserted and preferably in a form-fitting and / or non-positively and / or materially attached. Silicone switching mat (1) according to claim 6, characterized in that at least one receiving area (1f) has a bell membrane without tactile feedback and / or that, in particular in parallel to the surface of the circuit board (3) arranged portion of the receiving area (1f), elements , in particular in the form of depressions and / or elevations (9), which are provided by engagement in respectively corresponding elevations or depressions (10) of the inserting mandrel (4), preferably in its cover region (13), which are used for positioning and / or attachment of the insert (4) in the receiving area (1f) serve. Silicone switching mat (1) according to one of the preceding claims 1-5, characterized in that the cover region (8) has at least one receiving opening (11) in the form of a passage opening for the insertion of an inserting mandrel (4), preferably for inserting the inserting mandrel (4). with its foot region (12), wherein the receiving opening (11) is preferably stepped and / or has a groove or a ridge, so that the foot region (12) of the insert dome (4) has a positive fit and forms a closed surface of the silicone switch mat (1). can be fastened in this area, optionally with the additional help of a bonding agent. Silicone switching mat (1) according to one of the preceding claims, characterized in that the at least one inserting dome (4) has a cone-shaped cone (4a) which preferably revolves and projects upwards from a preferably circumferential foot region (12) for the generation of a tactile feedback, and a die Cone membrane (4a) upwards in one Plane parallel to the circuit board (3) partially or completely closing deck area (13), wherein on the circuit board facing underside of the deck area (13) a contact pill (4b) attached and / or embedded and / or injected, preferably based on a metal foam, or a Leitlack is applied. Silicone switching mat (1) according to one of the preceding claims, characterized in that the insert (4) consists of conductive liquid silicone or TPU. Silicone switching mat (1) according to any one of the preceding claims, characterized in that at least two, preferably at least 3 or more keys are provided with tactile feedback in the same silicone switching mat (1), which are formed by inserting domes (4) made of high quality elastomer. Silicone switching mat (1) according to one of the preceding claims, that in addition at least one further element from the following list is integrated: light shaft, pocket for electronic elements, positioning pin. A process for the preparation of a silicone switching mat (1) according to any one of the preceding claims, characterized in that the cover portion (8) from the low-order elastomer separate from Einlegedom (4) or the plurality of the insertion dome (4) is made of high-quality elastomer, and the insertion Dome (4) inserted into the cover area (8) and preferably in receiving areas (1f) and / or receiving openings (11) provided therein. A method according to claim 12, characterized in that the cover region (8) is designed application-specific, and the insert domes (4) are manufactured as a standard component. Use of a silicone switching mat according to one of the preceding claims as a switch in the automotive sector.

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