DE102008014443B4 - Illuminated push-button with potting compound - Google Patents

Abstract

Illuminated pushbutton consisting of a button (14) and a plunger (6) arranged thereon, the button (14) which can be actuated from the visible side of a front layer (1) being installed in the front layer (1) and with its plunger (6) a pressure sensor (5) arranged below the front layer (1), wherein one or more light sources (10) are installed below the front layer (1) whose light beams are perceptible from the visible side of the front layer (1), at least the intermediate space below Front layer (1) between the pressure sensor (5) and the keyboard surface (13) of the button (14) as Vergusskammer (22) is formed and in this Vergusskammer (22) a curable potting compound (8) is filled, characterized in that the button (14) with the plunger (6) arranged thereon is at least partially embedded in the potting compound.

Description

The invention relates to an illuminated probe with potting compound according to the preamble of claim 1.

From the date of the same applicant EP 1 332 505 B1 It is known to produce a lighting effect on a key in a keypad in that the cutout of the cover plate, and has cover plate cross-plates, wherein only the symbol webs of the symbol body pass through the cover plate openings and the other parts of the symbol body are covered by the cover plate webs of the cover plate ,

Such an electrical switch, in particular in its design as a piezo switch, has proven itself on a large scale.

In this document, the light sources are arranged on a board, which conduct the light rays over a light path away against a plastic body durchbluchtbaren, which finally forms the visible at the top relief symbol.

Disadvantage of this arrangement is that the light rays are passed in an air-filled cavity against the underside of the light guide, so that the system can not be sealed. It is therefore insufficiently protected against moisture penetration.

Another disadvantage is that certain lighting effects can not be generated, because the light effects resulting from the publication result only from the light color of the light source and the light color of the transilluminable plastic body. Other lighting effects, such. As the production of mixed colors and the like, are not possible.

In particular, it is also perceived as disadvantageous, a light guide, such. B. in the DE 195 28 831 A1 or US 2004/0136176 A1 to produce as a separate plastic part, which is associated with increased cost expenditure.

The actuating tappet is simultaneously formed in the aforementioned application as a diffuser. This assumes that the actuating plunger is always formed of a translucent material. In various applications, however, it is undesirable to make the actuating plunger of a translucent material, because on the one hand by the inevitable choice of material, the possibilities of power transmission via the material of the plunger are limited to the underlying piezo switch.

This is how the document shows EP 1 054 420 A1 an actuating button which is connected to an opaque plunger, wherein the plunger is incorporated in an elastically resilient and translucent mat. However, this is a silicone keypad.

Another disadvantage of using a translucent plunger is given in the limitation of the illumination. It has been shown that an illumination of the plunger alone is not sufficient. In addition, other illumination options could be applied, such. B. the use of a potting compound that acts as a diffuser and is designed to be light-conducting. This would have the advantage that the actuating plunger is completely enclosed air-tight and moisture-proof.

The utility model DE 83 04 932 U1 shows such a potting compound, wherein the plunger is mounted displaceably sealed in a housing-side sleeve, which in turn is enclosed by the potting compound. This has the disadvantage that only the housing-side sleeve, which leads the plunger is surrounded by the Versgussmasse and thus a costly structure is present, which can also be complicated only against the sealing compound sealed.

In the EP 1 332 505 B1 the light sources must be free from casting - so it must be avoided any contact with the potting compound - and the radiated light should always radiate via a Luftleitstrecke in the diffuser. This results in significant manufacturing disadvantages, because the light sources must always be free of potting and therefore installed and mounted as separate components.

Another disadvantage of EP 1 332 505 B1 is that the cover plate (there with 1 referred to) in direct positive connection with the filament (there as 9 must be). The luminous element has to penetrate the relief symbol in the front position and is positively connected to the front layer. Thus, however, there is the disadvantage that in the production always only a single front position with the lamp can be firmly connected and replaceable, as well as freely selectable in the design front layers are not possible.

This is also how the pamphlets show DE 101 23 633 A1 . DE 102 00 674 A1 . DE 78 14 996 U1 and DE 41 31 340 C1 a keyboard mat with operation buttons that engage in the keypad mat. In addition, the use of a potting compound is omitted in these documents.

The invention is therefore based on the DE 83 04 932 U1 the object of developing a lighted button so that it can be produced more cheaply, that it is protected against moisture and ensures a wide range of lighting effects.

To solve the problem, the invention is characterized by the technical teaching of claim 1.

An essential feature of the invention is that the gap between the pressure sensor and the keyboard surface of the button is designed as a potting chamber and in this potting a potting compound is filled, which cures and that the plunger is at least partially enclosed by the potting compound.

The term "plunger" is here understood to mean an actuating part which altogether serves to actuate the pressure sensor, which is thus suitable for being formed on its upper side as a button and which forwards the actuating force from the upper side (actuating side) to the side of the pressure sensor.

Such a plunger can also be covered by a front layer arranged above the arrangement, so that the term "key" then no longer applies and the plunger is then glued to the rear side of the front layer with this front layer.

Here, it is assumed that the "Shore hardness" of the potting compound is smaller than the bending stiffness of the mechanical forces transmitted ram, so that when you press the button on the keyboard surface is always ensured that the operating force on the - embedded in the potting compound - Tappet is transferred to the surface of the piezoelectric sensor also embedded in the potting compound. This prevents that the potting compound performs an unwanted transmission of mechanical forces.

Advantage of this measure is now that an absolutely moisture-sealed encapsulation of the piezoelectric sensor in the casting chamber there is also embedded plunger and that the potting compound forms the light guide, because according to the invention - in a comparison with the technical teaching of claim 1 extended version - the light source also embedded in the potting compound.

The basic idea of the invention thus relates to the common embedding of plunger and pressure sensor in an elastically yielding potting compound. It is not yet necessary to form the potting compound in a light-conducting manner.

The further idea also provides that the light sources are cast in the now photoconductive potting compound.

Thus, it is no longer necessary to form the plunger as a light guide or diffuser, as for example in the EP 1 332 505 B1 was required because in the present invention now the potting compound itself (due to the embedded light sources) "glows" and acts as a light guide.

Of course, the plunger may continue to be formed in the context of the present invention as a light guide, and then the potting compound serves as an additional light guide.

So you save yourself the otherwise necessary light guide, which is relatively expensive. The potting compound itself conducts the light sources located in the potting compound in the direction of the keyboard surface, at the same time has the advantage that the potting compound can be arbitrarily colored and in this case the light effect is controlled within wide limits. Thus, mixed light effects with respect to the light color of the light sources and the color of the light-conducting potting compound are possible.

Thus, it may be provided, for example, that the light source has a first light color and the potting compound a different light color, so that there is a mixed light effect. Furthermore, it can also be provided that a first, colored layer is arranged in the region of the transilluminable probe and a second colored layer is arranged in the region of the relief symbols.

In this way, the light colors can be changed within wide limits, especially because there is now the possibility to color the (photoconductive) potting compound.

In this way, there is the possibility that the plunger from another photoconductive material, for. B. also with a different light color, equips as compared to the pestle around extending potting compound, which includes the plunger.

In each potting thus one of the respective button associated differently colored potting compound can be filled, which changes the light effect from key to key.

It goes without saying that the pressure sensor can be configured as a piezosensor by way of example only. There are all pressure-sensitive pressure sensors into consideration, especially Hall sensors or photoelectric sensors in which a moving element is present. Likewise, inductive or mechanical Sensors in which a mechanically movable plunger likewise carries out a change of an element (eg an armature) as claimed essential to the invention.

Likewise, a capacitive sensor can be used as the pressure sensor.

Decisive is only that in the EP 1332 505 B1 Any existing light guide omitted and replaced by a complete chamber filling potting compound. This is - as stated - achieved significant benefits in terms of tightness and durability.

In particular, the plunger is guided in the potting compound due to the fact that the plunger is completely encapsulated by the potting compound, in a mechanically favorable manner. The plunger moves here only in the micron range in the direction of its longitudinal axis or transmits the mechanical shock waves, which are triggered by a pressure on the plunger associated with the button on the associated pressure sensor. Thus, a trackless, non-tactile switching is achieved.

Therefore, the plunger can not buckle and do not otherwise dodge laterally, which could affect the life of the plunger. The potting compound thus also serves as a mechanical guide element for the plunger and protects it against lateral buckling and wear.

After the potting compound extends to below the front of the keyboard, it also serves as a shock absorber in the sense of vandalism protection. Even if you hit the front with a hammer, these hammer blows will not lead to destruction of the upper front and the housing because the housing has internally the said Vergusskammern, which are completely filled with potting and so as a shock absorber and support of the housing serve. The housing is thereby mechanically stabilized.

This ensures at the same time that even with a hammer blow on the button associated plunger, which is preferably material integral with the button does not break off or buckles because he - as stated above - mechanically supported over the full cross section of the potting compound is.

In the preferred embodiment, the potting compound is used from an epoxy resin having a Shore hardness in the range of 80 to 90 Shore.

A Shore hardness tester consists of a spring-loaded pin made of hardened steel. Its depth of penetration into the material to be tested is a measure of the corresponding Shore hardness, which is measured on a scale of 0 Shore (2.5 mm penetration depth) to 100 Shore (0 mm penetration depth). A high number means a high degree of hardness. Accordingly, it results from the above-mentioned value of Shore hardness that it is a hard and non-compliant plastic.

Of course, it is also possible to use a silicone rubber or another castable permanently elastic plastic material instead of an epoxy resin.

However, especially light-stable, castable plastic materials are preferred which do not age and in which a long service life is given. This requirement corresponds best to the previously mentioned epoxy resin.

A further advantage of the application of the potting compound in the potting chambers provided according to the invention is that a significantly better heat dissipation of the light sources and light guides embedded in the potting compound is provided. These give their heat loss over a large area in the surrounding volume of the potting compound, and thus a long life of the light sources is ensured. A punctual heat load is thus avoided.

In particular, it is also provided in a development of the invention that the potting material from associated potting in the potting still flows out and located on the opposite side of the circuit board electronic components are also cast. Thus, even for these components that sit on the side opposite the Vergusskammern side of the PCB, a favorable moisture and oxidation protection guaranteed.

In a further embodiment of the present invention, it is provided that the overlay layer designated in the context of the present invention as a front layer can be designed as a replacement overlay or an alternate front layer.

This presupposes or implies that a front layer covers the entire keyboard surface and has no openings or other penetration possibilities to operate the underlying plunger.

In a modified embodiment, however, it may also be provided that these overlying, covering front layer also has corresponding openings for the actuation of the underlying plunger.

If you assume the simpler description due to the fact that the front position is completely closed, it is provided in this development that the actuating plunger is glued with its upper end on the underside of this front layer with a hard, less elastic adhesive. Thus, a force-transmitting positive and cohesive connection between the underside of the covering front layer and the top (front side) of the plunger is produced. The force acting on the front position actuating force is thus passed directly to the front side of the plunger.

The prerequisite here is, of course, that the front layer is glued on elastomeric layers on the top of a housing located below it at a distance. These elastomeric layers, with which the front layer is sealed adhered to the top of the housing, allow the front layer a certain bend at (actuating) pressure from above, allowing this bend - contrary to the restoring force of the elastomeric layers at the back of the front layer are arranged, is passed on the top of the respective plunger.

This results in the significant advantage that the entire structure, but without potting compound and without frontal position can be produced as a semi-finished component. Only when the material of the front panel is fixed, the final structure is made. The material of the front panel can be chosen arbitrarily and consists z. Example of a thin metal plate made of stainless steel, an aluminum plate, a plastic plate, a wooden plate, a glass plate, a wire layer plate or the like.

Once the material of the front panel is fixed, the entire structure is potted from below, which means that the potting is now filled with the translucent elastomeric potting material, which through corresponding column around the actuating plunger to the front (and thus the bottom of the applied front ) flows.

At the same time, the front side of the plunger is firmly bonded to the underside of the front layer via a hard adhesive, and also in the neighboring area between this cohesive adhesive bond still produce an adhesive bond between the bottom of the front and the top of the housing to this front position on the plungers in microns Area elastically bendable to arrange on the housing.

The size of the recess of the adhesive bond between the underside of the front panel and the top of the housing determines the extent to which the elastomeric adhesive layers approach towards the centrally located plunger and thus determines the elastomeric restoring force associated with the front panel upon actuation.

As a result, the shape and size of the actuating surface necessary to actuate through the closed frontal layer the tappet located thereunder.

It is important that the operating length of the plunger is variable within free limits, so that even very short plungers can be used, which may have a minimum length of less than 1 mm.

By using different plunger materials, the z. B. also be made of a hard ceramic material, the physical properties of the plunger materials can be harnessed. As an example, it can be stated that in the case of a very short ram, which consists of a ceramic material, only a low thermal expansion is to be expected, so that a stylus produced with it has a thermal decoupling to the piezosensor arranged underneath, and therefore only to a very limited extent is temperature sensitive. This is a clear improvement over systems that arrange the piezoelectric sensor directly on the front panel, because in these known systems, a thermal decoupling is not possible. Depending on the material selection of the ram used and the ram length, an EMC-protected and ESD-protected design of the probe is additionally achieved.

Because the actual piezosensor is completely isolated in the potting compound, it is electrically isolated and protected from electrostatic discharges that could destroy it. Likewise, the electromagnetic compatibility (ie the actual radiation) and the receiving sensitivity to harmful radiation are minimized.

It is even possible to make the elastomeric potting compound electrically conductive (for example, by the addition of graphite powder), so that it forms this potting compound as a Faraday cage. Thus, the sensitive piezoelectric sensor is completely encapsulated in the forming as Faraday cage potting compound.

Incidentally, this also applies to all other electronic components which are embedded in the potting compound, in particular also for the light sources.

Likewise, the casting compound made so electrically conductive acts as an electrical shield against the installed in the area of the underlying board electronic components.

It is therefore a shield layer, which is formed from the electrically conductive potting compound.

Thus, this results in the advantage that one forms the potting compound either optional insulating or electrically conductive.

Because it is provided that the potting compound flows through gaps radially in the outer region of the plunger to the underside of the covering front layer, thus an electrically conductive connection of a front layer to a housing-side grounding is possible. The electrically conductive potting compound then grounds the front.

In the following the invention will be explained in more detail with reference to drawings showing only one embodiment. Here are from the drawings and their description further features essential to the invention and advantages of the invention.

Show it:

1 : Schematically illustrates the top view of a front position of a keyboard with a button, which is designed as a relief symbol;

2 : Schematically sectioned by a keyboard with Vergusskammern;

3 : a strong schematic enlargement of the representation in 2 ;

4 a second embodiment with a section through a keyboard compared to the 3 ;

5 a third embodiment compared to 3 ;

6 FIG. 1 is a perspective view of a first embodiment of a plunger; FIG.

7 a second embodiment;

8th a third embodiment;

9 a fourth embodiment;

10 a fifth embodiment of a plunger;

11 : the sixth embodiment with an asymmetric plunger.

The keyboard basically consists of a front panel 1 made of a thin metal foil with z. B. a thickness of z. B. 0.5 mm is formed. Instead of a metallic front layer, a plastic, glass or wood front layer with a thickness corresponding to the material properties can also be used.

In the area of this front situation 1 are one or more recesses 20 . 21 arranged, by which in each case a key 14 protrudes. The recesses 20 relative to the outer diameter of the respective button 14 are chosen so that there is a very narrow gap 19 (please refer 3 ). This gap 19 has about the size of a capillary gap. The term "key 14 "Is here synonymous with the front front part of the plunger 6 used. The key 14 is thus material integral with the rear (sensor side) part of this plunger 6 connected.

Thus, the as a relief symbol 7 trained key 14 practically in a press fit into the recess 20 . 21 the front situation 1 fitted.

The fitting is done either mechanically, so the button 14 as a separate element in the recess 20 . 21 is fitted or it is directly to the back of the front panel 1 molded and then forms with the front layer a composite material composite. In this case, the gap would 19 omitted, and there is a material integral composite between the front layer 1 and the button 14 ,

The front situation 1 is here on top of a housing 2 arranged, this housing 2 preferably consists of a plastic material. It can also be formed from a metal material, in particular an aluminum material.

In the case 2 are larger recesses 21 present, essentially with the smaller sized recesses 20 in the front position 1 aligned.

It is also provided that the front situation 1 also with the housing 2 is injected behind. In this case, the plastic housing 2 directly to the plastic front layer 1 be sprayed.

It is then a composite material composite between the front layer and the housing 2 given.

It is important now that in the area of the housing 2 individual potting chambers 22 are formed.

Each potting chamber is formed by side walls of the housing 2 , associated end walls and in addition by housing webs 9 which each define a potting chamber. Every casting chamber 22 is preferably a button 14 assigned.

The underside will be any potting chamber 22 through a circuit board 3 completed, taking in the circuit board 3 grouting 4 are provided for filling the liquid and curable potting material.

It is of course possible, the Vergusskammer 22 make larger, by some housing webs 9 be omitted. In this case, would in the potting a variety of buttons 14 with associated rams 6 protrude and all would be surrounded by the same potting compound. The housing webs 9 thus serve as Lichtabschottung, to avoid the light on the top of the circuit board 3 arranged light source 10 in the adjacent grouting chamber 22 device.

It is - as stated - also possible, the housing webs 9 to leave out, to make sure that in a Vergusskammer 22 arranged light source 10 other buttons illuminated from below.

It is important now that the still liquid and curable potting compound 8th over the potting holes 4 into the potting chamber 22 is initiated and there after a certain time hardens.

This is at the same time in the potting 22 arranged pressure sensor 5 encapsulated and completely from the potting compound 8th surround.

Over an adhesive layer 11 is the bottom of the pestle 6 the button 14 with the pressure-sensitive side of the pressure sensor 5 connected.

To a mechanically de-energized connection of the plunger 6 to the pressure-sensitive top of the pressure sensor 5 to allow, it is provided when the circuit board 3 when attaching to the housing 2 at stops 12 strikes and in this case a certain distance between the underside of the plunger 6 and the pressure sensitive top of the sensor 5 given is. This distance is now through a hardenable adhesive 11 bridged, so when fitting the circuit board 3 in the case of the glue 11 is still liquid and then hardens. In this way, the mechanical stress-free placement of the underside of the plunger 6 on the pressure sensitive top of the sensor 5 guaranteed.

This measure of attachment of the circuit board 3 in conjunction with the mechanical coupling of the plunger 6 on the pressure sensor 5 takes place before the introduction of the potting compound 8th into the potting chambers 22 ,

In a preferred embodiment, the button 14 as a relief symbol 7 educated as it is the subject of one's own EP 1 332 505 B1 is. The disclosure of this document is therefore intended to be fully encompassed by the disclosure of this invention.

In other embodiments, the key 14 However, also be transparent, as in 3 is shown.

Of course, it is possible on the actuating surface 13 the button 14 applying, milling, gluing or otherwise fixing different translucent symbols.

It is important now that when pressure on the actuating surface 13 in the direction of the arrow 15 the pestle 6 Moves here only in the micron range (eg., In the range of 2 to 10 microns), or transfers the mechanical shock waves, which by a pressure on the plunger 6 assigned key 14 on the likewise assigned pressure sensor 5 to be triggered. This mechanical pressure and the associated layer change in the arrow direction 15 is over the now cured adhesive layer 11 on the pressure-sensitive side of the pressure sensor 5 forwarded and thus forms a trackless, non-tactile switching.

This is due to the complete pouring of the button 14 with the pestle 6 a back pressure in the direction of the arrow 16 on the bottom of the button 14 ,

The back pressure in the direction of the arrow 16 must be less than the force in the direction of the arrow 15 from above on the button 14 is applied.

This force difference is achieved by adjusting the Shore hardness of the potting compound 8th set.

It is important now that the entire casting compound 8th acts as a light guide, it being preferred if the potting compound is transparent or translucent.

This will send the light sources 10 the rays of light 18 in the potting compound 8th in and those rays of light 18 will also be at the different located there surfaces in the arrow directions 17 reflected and on the bottom, side end walls and the environment of the button 14 and the pestle 6 in the key 14 initiated.

The potting compound scatters the light and thus forms a diffuser, which ensures a particularly favorable light distribution. The diffuser has the advantage that the points of light passing through the light sources 10 otherwise visible from the top of the front panel 1 are no longer visible. This ensures that the relief symbol 7 is homogeneously illuminated at a minimum of light output, which by the light sources 10 must be applied.

In 4 is essentially the same construction as in 3 represented, so that the local reference numerals also for the structure according to 4 apply unchanged.

Deviating from the construction in 3 show the 4 however, a front position 1 , preferably as an uninterrupted cover layer above the actuating surface of the button 14 is arranged.

Such a front layer may be formed as a closed cover layer and consists for example of a plastic plate, a metal plate, a wooden plate, a glass plate or the like more.

It can also be provided that in this front position recesses 24 are provided, if necessary, also lighting bars 23 form, so that through these recesses through the potting compound 8th penetrating light, which is also the column 19 . 20 permeates into the area of the frontal position 1 arrives.

The front layer can therefore also be made of a translucent material.

Important here is that for the production of such a button, the potting compound 8th is poured and gap-filling through the columns 19 penetrates and up an annular recess 20 passes, so that this annular recess is completely filled by the potting compound and directly to the back of the front panel 1 followed. This ensures that the light-conducting potting compound 8th to the back of the front panel 1 enough. This will also all light rays 18 in the direction of the arrow 17 get up to the bottom of the front 1 continued.

Thus, all cavities in the radial outer region of the plunger 6 and the button 14 completely hermetically sealed and protected against moisture. Furthermore, the potting compound forms directly at the bottom of the front layer 1 in the region of the recess 20 is arranged filling, a mechanical counter bearing against vandalism attacks on the front panel 1 ,

It is also important that the top of the button 14 (or as a more general term here as a ram 6 designated) with a relatively hard adhesive 11b at the back of the front panel 1 is glued to achieve a positive and positive power transmission of an actuating force in the direction of arrow 15 on the top of the front panel 1 acts.

It is also preferred when on the opposite side of the plunger 6 arranged glue 11a is designed as a hard and non-elastic adhesive. In this way, a vibration- and shrinkage-free mechanical operating path directly from the front 1 on the top of the pressure sensor 5 reached.

In another embodiment, however, it may also be provided that the adhesive 11a . 11b omitted and / or only one of the two adhesive layers 11a . 11b are present, so that then instead of the apportioned adhesive layer 11a . 11b there is direct body contact with the corresponding opposite surface.

Likewise, based on the 6 to 10 yet to be explained that the shaping of the plunger 6 in itself is variable within wide limits, so as to the operating force, which is entered from the top of the front layer, in the direction of the embedded pressure sensor 5 to be able to control.

The 4 also shows that on the top of the case 2 an adhesive layer 25 is arranged, which acts as a spacer layer. It remains open whether this adhesive layer 25 is designed as an elastomeric adhesive layer or as a hard adhesive layer, because it only has the task of a firm connection between the front layer 1 and the housing 2 manufacture.

The thickness of the adhesive layer 25 determines the deflection of the front panel 1 in the direction of the arrow 15 , because yes the front position in the area of the recess 20 , which with elastic potting compound 8th is filled, is pressed into it.

This closes the adhesive layer 25 directly to the radially inwardly formed as an annular space recess 20 on, with the potting compound 8th is filled.

This results in the advantage that overall the front position 1 can be replaced, because depending on the application and design purpose can different front positions slightly later with the structure after 4 get connected.

It only requires the selection of a specific front position 1 which then with the help of the adhesive layer 25 and the adhesive layer 11b is installed, after which then the entire structure from the rear with the potting compound 8th is poured, which then - when using appropriate riser channels - flows into the recess gap filling and mold filling.

The 5 shows as a further embodiment an opposite 3 and 4 modified embodiment, in which the same parts are provided with the same reference numerals.

Here you can see that the length of the plunger 6 can be varied greatly, because here the ram length is very short and may for example be less than 1 mm.

This results in a non-obvious, thermal decoupling effect, because it is possible, such a plunger made of a thermally resistant material such. B. to make a ceramic material having a low expansion coefficient. Therefore, such a probe is particularly temperature stable, because a corresponding thermal expansion of the plunger 6 not taking place.

The pyro effect, which is particularly dreaded in piezo keyboards, no longer occurs here because the thermal decoupling of the piezosensor 5 with a ceramic tappet arranged above it 6 a temperature line on the underlying piezo sensor 5 and also an undesirable temperature expansion of the plunger 6 no longer takes place.

The mentioned embodiment in 5 can be used with all lighting effects described in the aforementioned embodiments. It therefore apply to this embodiment, all explanations, as they are based on the 1 to 4 were given. Therefore, it is equally possible the plunger 6 form non-translucent, which causes only the annulus in the recess 20 that with potting compound 8th is filled as a luminous ring is present.

Such a luminous appearance can, as shown in 4 (see the local light bars 23 ) also up through the front 1 be passed through.

Likewise, the front position 1 be formed of a transparent material and then lights, because the annulus in the region of the recess 20 that with potting compound 8th is filled and illuminated by the light sources, "glows".

For all front positions 1 , which have been described with reference to the preceding figures, it is not necessary for the solution that the front layer is formed as a flat plate. It can also be deformed three-dimensionally; it may have embossments, elevations or depressions and be decorated with arbitrary symbols and reliefs. The shape of the case 2 and the adhesive layer arranged thereon 25 then follows the possibly three-dimensionally deformed front position The length of the actuating tappet 6 is then adjusted accordingly and adapted to the deformed front position.

The 6 to 10 show various embodiments of actuating tappets, wherein the 6 a double conical shape of a pestle 6a represents. Here is the upper actuating surface 26a formed as a conical, trough-shaped annular surface, which is preferably recessed concave. The recess is preferred with the adhesive 11b filled as he is based on the preceding embodiments of 4 and 5 was explained.

The operating force in the direction of the arrow 15 From above, therefore, is due to the narrower constricted cross-section down toward the lower actuating surface 27a forwarded, the form-fitting and (by the adhesive used) cohesively on top of the pressure sensor 5 rests.

By choosing the area difference of the upper actuating surface 26a in comparison to the smaller lower actuating surface 27a the actuating force is adjusted accordingly.

Of course it is possible to use the biconical body of the tappet 6a form as a hollow cylinder or as a solid cylinder and to fill this total with adhesive.

It is important that in the embodiment according to 6 the upper trough-shaped actuating surface 26a with the glue 11b is filled while the lower actuating surface 27a with the glue 11a is filled.

Advantage of the trough-shaped design of the actuating surfaces 26a . 27a is that the adhesive receptacle can be precisely defined and thus there is little risk that the adhesive escapes out of the concave trough.

A similar embodiment shows the 7 , where it can be seen that a same trough-shaped actuating surface 26a is present, but that the lower actuating surface 27c is designed as a rounded tip. The area of the tip is not glued. In the area of the rounded sharpened actuating surface 27c will not be with the Top of the pressure sensor 5 bonded. This assumes that the plunger 6b a mechanical bias on the pressure sensor 5 achieved, namely the fact that he under mechanical bias in the layer structure, for example after 4 or 5 is installed. This ensures that no potting compound penetrates between plunger and sensor, because yes, the rounded tip of the actuating surface 27a frictionally on the top of the pressure sensor 5 rests and thus there is no room for the penetration of potting compound in this contact area.

This makes it possible, the operating force in the area of the sharpened rounded actuating surface 27c focus and further concentration takes place when, instead of the rounded actuating surface 27 which has a relatively small area, instead a peak 28 is used, which is directly frictionally on top of the pressure sensor 5 rests. This also a simplification of the assembly is achieved because only a splice for the adhesive 11b in the area of the trough-shaped actuating surface 26a necessary is.

In the reverse manner, this also applies to the embodiment according to 10 , which is the mechanical equivalent of 7 represents. For this embodiment, all explanations, as they are based on the 7 were given. In contrast, the rounded tip 26c directed upwards and lies at the bottom of the front layer 1 on while the actuating surface 27b again trough-shaped and with the adhesive 11a at the top of the pressure sensor 5 is glued on.

Instead of the rounded relatively small actuating surface 26c can for the ram shown there 6e also a tip 28 be used.

The 9 shows the kinematic reversal to a ram 6a to 6 and shows a pestle 6c , in reverse to the explanations after 6 a relatively small actuating surface 26b at the top and a larger actuating surface 27b wears at the bottom. Both actuating surfaces are formed trough-shaped and are with the corresponding adhesive layers 11a . 11b filled.

The 8th shows a further embodiment, a plunger 6d , whose actuating surfaces 26a . 27b are formed relatively equal. The connection region can be designed either as a constricted conical region, as a hollow cylinder or as bulbous (convex), like the dashed lines 29 in 8th represent.

In all embodiments, that on the pressure sensor 5 resting surface of the plunger 6a - 6e Also material einstückig may be molded with the pressure sensor itself and / or with the front layer.

The invention thus also provides embodiments in which in each case the foot side of the plunger 6a - 6e material integral with the surface of the pressure sensor 5 is connected or optionally also the upper end side of the plunger 6a - 6e Material integral by injection with the underside of the front layer 1 connected is. Instead of the connection with the front position 1 itself can also be a use in the front position 1 be used with the respective actuating surface 26a -C material is integrally connected by injection molding.

It is therefore intended that if the front position 1 is designed as a plastic overlay that on the underside already all ram 6a - 6e are sprayed.

In the opposite case, this also applies to the pressure sensor 5 , on the top already already the plunger 6a - 6e with their corresponding actuating surfaces 27a -C material are molded in one piece.

After the pestle 6a - 6e can also be formed asymmetrically, this results in the possibility that the plunger offset from the surface of the pressure sensor 5 is arranged so that the actuating surfaces 26 . 27 not directly aligned with each other, but are arranged offset in the axial direction to each other. This shows the 11 ,

Thus, the pressure sensor is no longer flush below the actuating surface 26 to the front 1 arranged, and it is therefore possible directly in this aligned longitudinal axis of the upper actuating surface 26 To arrange a light source, thus providing a direct, straight light incident on the actuating surface 27 causes because of the plunger from the actuating surface 27 angled and offset to this in the staggered pressure sensor 5 opens.

This is in 11 shown where it can be seen that the plunger 6f is formed asymmetrically and the two associated actuating surfaces 26a . 27a are not aligned with each other. Therefore, it is possible here that in alignment with the upper actuating surface 26a a light source 10 is arranged, which a point light beam directly on the back of the actuating surface 26a passes.

LIST OF REFERENCE NUMBERS

1

front Location

2

casing

3

circuit board

4

casting opening

5

pressure sensor

6

tappet

7

relief symbol

8th

potting compound

9

housing web

10

light source

11

Glue

12

attack

13

keyboard surface

14

button

15

arrow

16

arrow

17

arrow

18

beam of light

19

gap

20

Recess on the front

21

Recess housing

22

sealing chamber

23

light bar

24

recess

25

adhesive layer

26

Actuating surface a, b, c

27

Actuating surface a, b, c

28

top

29

line

Claims (33)

Illuminated pushbutton consisting of a button ( 14 ) and a plunger ( 6 ), whereby the from the visible side of a front position ( 1 ) operable button ( 14 ) in the front position ( 1 ) and with its plunger ( 6 ) to one below the front ( 1 ) arranged pressure sensor ( 5 ), wherein one or more light sources ( 10 ) below the front ( 1 ) are installed, the light rays from the visible side of the front layer ( 1 ) are perceptible, wherein at least the space below the front layer ( 1 ) between the pressure sensor ( 5 ) and the keyboard interface ( 13 ) of the button ( 14 ) as potting chamber ( 22 ) is formed and in this Vergusskammer ( 22 ) a curable potting compound ( 8th ), characterized in that the key ( 14 ) with the ram ( 6 ) is at least partially embedded in the potting compound. Button according to claim 1, characterized in that the front layer ( 1 ) one or more recesses ( 20 ), each of which as a relief symbol ( 7 ) trained key ( 14 ), wherein the inner diameter of the recess ( 20 ) with respect to the outer diameter of the button ( 14 ) a capillary gap ( 19 ), whereby the key ( 14 ) in the recess ( 20 ) of the front situation ( 1 ) is fitted almost as a press fit. Button according to one of the preceding claims 1 to 2, characterized in that the button ( 14 ) a touchpad ( 13 ) and in the recess ( 20 ) is fitted as a separate element or directly to the back of the front layer ( 1 ) and forms a material integral composite. Probe according to one of the preceding claims 1 to 3, characterized in that the front layer ( 1 ) on top of a housing ( 2 ) or the housing ( 2 ) to the front ( 1 ) and forms a material-integral composite, wherein the housing recesses ( 21 ), which substantially with the recesses ( 20 ) in the front position ( 1 ) are aligned. Probe according to one of the preceding claims 1 to 4, characterized in that the housing ( 2 ) individual casting chambers ( 22 ), each casting chamber ( 22 ) by means of side and associated end walls of the housing ( 2 ) and housing webs ( 9 ) is formed and preferably for receiving a button ( 14 ) is trained. Button according to one of the preceding claims 1 to 5, characterized in that the button ( 14 ) in the direction of the pressure sensor ( 5 ) a material integrally arranged plunger ( 6 ), which with its free underside by means of a curable adhesive ( 11 ) with the pressure-sensitive surface of the pressure sensor ( 5 ) and a mechanical pressure transmission from the actuating surface ( 13 ) of the button ( 14 ) in the direction of the arrow ( 15 ) over the cured adhesive ( 11 ) on the pressure sensor ( 1 ) trains. Probe according to one of the preceding claims 1 to 6, characterized in that the casting chamber ( 22 ) is filled by means of a liquid and curable potting material, which via arranged potting ( 4 ) in a housing closing the circuit board ( 3 ) of the potting chamber ( 22 ) and in the potting chamber ( 22 ) arranged part of the button ( 14 ) and the pressure sensor ( 5 ) encloses. Push-button according to one of the preceding claims 1 to 7, characterized in that in the housing ( 2 ) arranged housing webs ( 9 ) a Lichtabschottung the generated light beam ( 18 ) for adjacent potting chambers ( 22 ) train. Probe according to one of the preceding claims 1 to 8, characterized in that the potting compound has a defined Shore hardness. Push-button according to one of the preceding claims 1 to 9, characterized in that the end walls of the housing ( 2 ) Attacks ( 12 ), which in mounting the printed circuit board ( 3 ) on the housing ( 2 ) a distance between the underside of the plunger ( 6 ) and the pressure-sensitive surface of the pressure sensor ( 5 ), whereby a mechanically tension-free connection of the plunger ( 6 ) when fitting the circuit board ( 3 ) in the housing ( 2 ) before the introduction of the potting compound ( 8th ) into the potting chamber ( 22 ) is guaranteed. Push-button according to one of the preceding claims 1 to 10, characterized in that upon actuation of the actuating surface ( 13 ) in the direction of the arrow ( 15 ) the resulting mechanical pressure due to the complete pouring of the button ( 14 ) with the plunger ( 6 ) a back pressure in the direction of arrow ( 16 ) on the underside of the button ( 14 ), wherein the generated counter-pressure less than the force generated due to an adjustable Shore hardness of the potting compound ( 8th ) is trained. Probe according to one of the preceding claims 1 to 11, characterized in that the light source arranged by the 10 ) into the potting compound ( 8th ) transmitted light beams ( 18 ) on different surfaces in the direction of the arrow ( 17 ) and on the underside, lateral end walls and the surroundings of the button ( 14 ) and the plunger ( 6 ) into the button ( 14 ), the potting compound ( 22 ) the light beams ( 18 ) and forms a diffuser, which from the top of the front layer ( 1 ) visible light points of the light source ( 10 ) and the relief symbol is homogeneously illuminated with a minimum of generated light output. Probe according to one of the preceding claims 1 to 12, characterized in that the potting compound ( 8th ) is formed light-conducting. Probe according to one of the preceding claims 1 to 13, characterized in that the casting compound ( 8th ) is formed electrically insulating Probe according to one of the preceding claims 1 to 14, characterized in that the potting compound ( 8th ) is electrically conductive. Probe according to one of the preceding claims 1 to 15, characterized in that the front layer ( 1 ) via the electrically conductive potting compound ( 8th ) with the housing ( 2 ) and optionally electrically conductively connected to electrical functional elements. Probe according to one of the preceding claims 1 to 16, characterized in that the front layer ( 1 ) as an uninterrupted cover layer above the actuating surface of the button ( 14 ) is arranged. Push-button according to claim 17, characterized in that the upper side of the button ( 14 ) with a relatively hard glue ( 11b ) on the back of the front panel ( 1 ) is glued Probe according to claim 17 or 18, characterized in that the sensor-side side of the plunger ( 6 ) with an adhesive ( 11a ) on top of the pressure sensor ( 5 ) is glued. Push-button according to one of the preceding claims 1 to 19, characterized in that on the upper side of the housing ( 2 ) an adhesive layer ( 25 ) arranged as a spacer layer for the front layer ( 1 ) serves. Probe according to one of the preceding claims 1 to 20, characterized in that the adhesive layer ( 25 ) directly to the radially inwardly formed as an annular space recess ( 20 ) connected with the potting compound ( 8th ) and that the thickness of the adhesive layer ( 25 ) the deflection of the front layer ( 1 ) certainly. Push-button according to one of the preceding claims 1 to 21, characterized in that the button ( 14 ) associated plunger of a material of lowest thermal expansion, z. B. ceramic, consists. Probe according to one of the preceding claims 1 to 22, characterized in that the continuous and uninterrupted front layer ( 1 ) is formed of a translucent material and lights on the visible side, because the annular space in the region of the recess ( 20 ) by the illumination of the potting compound ( 8th ) itself lights up. Probe according to one of the preceding claims 1 to 23, characterized in that the plunger ( 6 . 6a - 6f ) has a double-conical shape. Probe according to claim 24, characterized in that the upper actuating surface ( 26a ) the plunger ( 6 . 6a - 6f ) is formed as a conical, trough-shaped annular surface, which is preferably recessed concave. Probe according to claim 24 or 25, characterized in that the lower actuating surface ( 27a ) the plunger ( 6 . 6a - 6f ) is formed as a conical, trough-shaped annular surface, which is preferably recessed concave. Probe according to one of claims 24 to 26, characterized in that the size of the upper actuating surface ( 26a ) the plunger ( 6 . 6a - 6f ) of the size of the lower actuating surface ( 27a ) is different. Probe according to one of claims 24 to 27, characterized in that the upper actuating surface ( 26a ) of the plunger ( 6 . 6a - 6f ) associated adhesive ( 11b ) in its consistency, hardness and composition of the lower actuating surface ( 27a ) associated adhesive ( 11a ) deviates. Probe according to one of claims 24 to 28, characterized in that at least one of the actuating surfaces ( 26a . 27a ) the plunger ( 6 . 6a - 6f ) as a tip ( 26c . 27c . 28 ) is trained. Probe according to one of claims 24 to 29, characterized in that in each case the foot side of the plunger ( 6a - 6f ) material integral with the surface of the pressure sensor ( 5 ) connected is. Probe according to one of claims 24 to 30, characterized in that also the upper end face of the plunger ( 6a - 6f ) material in one piece by injection molding with the underside of the front layer ( 1 ) connected is. Probe according to one of claims 24 to 31, characterized in that an insert in the front position ( 1 ) is present, with which the respective actuating surface ( 26a -C) of the plunger ( 6 . 6a - 6f ) is integrally connected by injection molding. Probe according to one of claims 24 to 32, characterized in that the plunger ( 6a - 6f ) offset to the surface of the pressure sensor ( 5 ) is arranged, and that the actuating surfaces ( 26 . 27 ) are not directly aligned with each other, but in the axial direction offset from one another.

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