DE102011079902A1 - Integrated surface-switching element installed in e.g. roof of vehicle, has pressure piece provided between decorative support surface and functional layer so that functional layer is biased with respect to decorative support surface - Google Patents

Abstract

The integrated surface-switching element (1) has decorative support surface that is attached to a chamber (10). The chamber includes one or more side walls (101) and a functional surface (102) provided with an opening (103). A functional layer (13) is provided within the chamber to generate a switching signal. A pressure piece (203) is provided between the decorative support surface and the functional layer, and is arranged in opening of chamber so that the functional layer is biased with respect to the decorative support surface.

Description

Technical area

The invention relates to the construction of a surface-integrated switching element, in particular for integration in interior trim parts of vehicles.

State of the art

Surface-integrated switches for vehicles are known in principle from the prior art. For example, the German patent application discloses DE 103 59 297 A1 the construction of a surface-integrated switch, in particular for use in motor vehicles. It can be used as a switching element, a pressure-sensitive, piezo-active element use. The switching element described is arranged behind a decorative surface of an interior trim part of a motor vehicle. A slight deformation of the decorative surface causes the formation of an electrical voltage in the piezoactive material of the switching element, which can be detected as a switching signal from an electronic system.

From the unpublished German patent application DE 10 2011 003 512 It is known to arrange the switching element within a chamber and to clamp it via a spring element within the chamber. The chamber is then connected to the decor carrier layer via a gluing process. Since the switching element described is backlit (eg as search or function lighting), at least the side of the chamber which is connected to the decor carrier layer is made transparent. For this reason, the chamber is formed in a complex two-component injection molding process. Likewise, a transparent adhesive is used to bond the chamber to the decor carrier layer.

Experiments have shown that especially the gluing process is time-consuming and material-consuming.

The present invention is based on the object to provide a module with a surface-integrated switching element, in which the individual components are as simple and inexpensive to manufacture and connect to the switching module. In particular, the elaborate production processes, such as two-component injection molding and adhesive processes should be dispensed with.

Description of the invention

The switching element according to the invention consists of a chamber, for example of a plastic, a metal or another suitable material and a decor carrier surface connected to the chamber.

The decorative support surface can preferably be a back layer of an interior trim part of a motor vehicle, such as an instrument panel, a door inner panel, a (center) console, a seat back, an armrest or a vehicle roof. Alternatively, the decorative support surface is a control panel or a trim part, which is mounted in a subsequent step on an interior trim part of a vehicle.

The chamber consists of one or more side walls and a functional surface, wherein the functional surface is arranged adjacent to a decor carrier surface.

A functional layer, preferably a pressure-sensitive sensor, is arranged in the chamber. The pressure-sensitive sensor is preferably fixed via a spring element within the chamber.

In the functional surface of the chamber, an opening is arranged. The opening is in its size or shape such that falling out of the functional layer from the chamber is not possible.

In the opening of the functional surface, a pressure piece is arranged. The pressure piece is designed such that after the attachment of the chamber to the decorative support surface, the functional layer arranged in the chamber is prestressed relative to the decorative support surface. Advantageously, the pressure piece extends through the opening in the direction of the functional layer at least in a pre-assembly position, in which the frame is not yet completely connected to the decorative carrier layer, preferably locked. In other words, the thickness of the pressure piece is preferably greater than the thickness of the functional surface, so that the pressure piece can completely penetrate the opening, so that the pressure applied by the operator to the decorative layer on the decorative support surface and the pressure piece and any further intermediate layers and the functional layer forwarded becomes.

In the operation of the switching element by a pressure on the decor carrier surface, this pressure and the resulting slight deformation of the Dekorträgerfläche is transmitted via the pressure piece to the functional layer. In this case, additional, preferably incompressible layers can be arranged between the pressure piece and the decor carrier surface and / or the functional layer. Preferably, this results in a layer structure in which the layers are in close contact with each other in order to transfer the applied pressure enable. Due to the bias of the components to each other production-related tolerances are minimized and operating problems of the switching element avoided. In particular, the correct transfer even the smallest switching paths can be ensured in the functional layer.

Small and thus exact switching paths according to the invention are necessary in particular when the functional layer is a piezosensor, for example a foil which is coated with piezoactive material. Such films require a switching path on the order of a few micrometers (5-10 μm). An alternative to piezosensors are also known as "metal over cap" (i. F. MOC) sensors described structures. The switching paths of such sensors are of the same order of magnitude as the values previously described for piezo sensors. MOC sensors are capacitive sensors which are arranged on a carrier layer. Spaced to the capacitive sensors is ever an electrically conductive layer (usually a metallic layer) is provided. Deformation of this conductive layer causes a change in the electromagnetic field surrounding the layer, which is detected by the capacitive sensor. An advantage of such sensors over conventional capacitive sensors is the tactile, location-accurate detection of the switching signal, as well as their small installation size. Preferably, the MOC sensor is designed to be transparent or translucent and can be transilluminated by a light source arranged behind the sensor. Furthermore, the functional layer may be a so-called "Force Sensing Resistor" (in the first instance FSR sensors), with such sensors having to provide a larger switching path than the aforementioned sensor types.

The pressure piece arranged between the functional layer and the decor carrier surface can in a preferred embodiment be formed integrally with the decorative carrier surface. In this case, the decor carrier surface has a projection projecting through the region of the opening of the functional surface. Such a projection can advantageously be formed by providing or creating in the decorative support surface a recess into which the areas of the functional surface of the chamber can be received which surround the opening.

Such a material reduction of the decor carrier surface around the pressure piece designed as a projection has the further advantage that a deformation of the decor carrier surface in the region of the pressure piece is facilitated if the decor carrier surface consists of a rigid material and in addition a possible crosstalk to adjacent switching modules is prevented.

Alternatively, the pressure piece may also be an element which is at least partially disposed within the chamber and has a projection which projects through the opening in the functional surface of the chamber in the direction of the decorative support surface. In a particularly preferred embodiment, the pressure piece has a T-shaped cross section, wherein the lateral ends of the bars of the T project beyond the region of the opening of the functional surface within the chamber and thereby come into contact with the functional surface during the pre-assembly of the functional layer within the chamber and prevent the pressure piece from falling out.

Finally, it is also possible for the pressure piece to be a single component which is arranged in the opening of the functional surface before the chamber is mounted on the decorative support surface. In the simplest case, the pressure piece may be a round or polygonal plate. Preferably, the pressure piece has on its circumference elements to the thrust piece in the arrangement in the opening of the functional surface axially, d. H. substantially perpendicular to the decorative support surface, slidably to fix, whereby falling out of the pressure piece can be avoided before or during assembly of the chamber to the decorative support surface. In a particularly preferred embodiment variant, the pressure piece has a groove on its circumference, in which engage at least partial regions of the functional surface. By designing the width of the groove, the desired axial displacement can be ensured.

The pressure piece has a layer thickness which is greater than the maximum layer thickness of the functional surface of the chamber. This can ensure that the functional layer, for example, against the force of a spring element, after the assembly of the chamber, is biased against the decorative support surface.

Depending on the type and number of sensor or generally functional layers arranged within the chamber, the layer thickness of the pressure piece can preferably be selected such that, when the chamber is mounted on the decorative support surface, a previously determined layer thickness always results. This has the advantage that the spring element provided for tensioning the functional layer (s) can be executed independently of the occupancy of the chamber and preassembled in the chamber at a constant mounting position.

Between the decor carrier layer and the functional surface of the chamber, an air gap may be present in the mounted state in the regions surrounding the pressure element. In an alternative embodiment is at the Function surface or the decor carrier layer in this area a compressible material (for example, a plastic foam) arranged to prevent any possible false noises.

The pressure piece is preferably made of a light-transmissive material. A light-transmissive material in the sense of the invention is a translucent, preferably transparent material.

In a preferred embodiment, the pressure piece is designed as a light guide such that the light of a light source arranged inside the chamber (for example an LED) is laterally coupled into the pressure piece and deflected in the direction of the decorative support surface. For this purpose, the pressure piece may have a correspondingly designed surface structure on its side facing the functional layer. The structure for deflecting light can be a multiplicity of deliberately introduced deflecting geometries, such as channel, pyramid, conical or hemispherical indentations or bulges, which are provided in the production of the pressure piece on the aforementioned surface, or subsequently attached, z. B. be embossed.

Accordingly, the pressure piece can have a light-focusing focusing layer on its side facing the decorative support surface to optimize the quality of the light extraction or else be provided with a correspondingly designed surface structure. The structure for light bundling can in turn be a multiplicity of deliberately introduced focusing geometries, such as trough, pyramid, conical or hemispherical indentations or bulges, which are provided in the production of the pressure piece on the aforementioned surface, or subsequently applied , z. B. be embossed.

Alternatively or additionally, the light-permeable material of the pressure piece, at least in the region arranged within the chamber light-reflecting particles, such as hollow glass spheres, which cause light scattering, preferably a light steering in the direction of decor carrier surface.

With particular preference, the geometry of the pressure piece is optimized with regard to the light coupling in such a way that it projects beyond the diameter of the opening of the functional surface in the direction of the light sources within the chamber only in the areas in which light sources are arranged.

A pressure piece designed in this way eliminates the need for additional light-guiding or light-focusing layers arranged within the chamber and consequently reduces the number of parts required to construct the switching module. In order to further optimize the light extraction, the peripheral surfaces of the pressure element which are arranged outside the chamber and are substantially perpendicular to the decorative support surface could be designed to be light-reflecting.

At least the side walls of the chamber are designed as a light barrier. That is, the material for forming the sidewalls is substantially opaque. In this way it is avoided that in an adjacent arrangement of a plurality of switching elements, to influence the lighting of the switching elements with each other. Preferably, the functional surface of the chamber is designed as a light barrier. In this case, light extraction would take place only through the opening provided in the functional surface and the pressure piece arranged therein. Such a designed chamber can be inexpensively made of plastic in a conventional one-component injection molding.

Particularly preferably, the side walls of the chamber on the inside of the chamber as a light reflector (white, specular, ...) are formed. In this way, light rays that do not extend in the direction of the opening of the functional surface are thrown back within the chamber and, as a result, the amount of light emerging from the chamber is significantly increased.

The decorative support surface preferably also consists of a light-transmissible material, for example of a transparent plastic. Such a component can also be produced inexpensively in a conventional one-component injection molding process.

On the decor carrier surface may be arranged on the vehicle interior side facing a decorative layer. The decorative layer is designed to be light-flooded in the region of the opening and preferably has a symbolism or a pattern. The decorative layer may be a laminated or with the decorative support surface hinterspritzte foil, or alternatively a leather or a textile. The decorative layer can also be a coating applied to the decor carrier surface made of a hardening or otherwise solidifying material.

The attachment of the chamber to the decorative support surface may preferably be effected via latching elements. In this case, the chamber has at its outer periphery, for example, at least two opposing detents, which correspond with arranged on the decorative support surface locking receptacles.

In a preferred embodiment variant, the spring element provided for clamping the functional layer within the chamber is designed such that the final locking of the spring element at the same time causes the preferably releasable attachment of the chamber to the decorative support surface. For this purpose, the spring element has at least two, preferably three the extent of the chamber outstanding arms on the serve as a detent and correspond with arranged on the decorative support surface locking receptacles.

In order to ensure a functionally appropriate tensioning of the functional layer in the chamber, slots are provided in the side wall of the chamber at the points at which the arms of the spring element project beyond the circumference of the chamber, as a result of which the spring element is displaceable at least in the direction of the functional layer. The geometry of the slots may be such as to provide a captive securing which allows pre-assembly of the spring in the chamber and prevents the spring element from falling out of this preassembly position. Furthermore, the geometry of the slots can have additional latching receptacles in which the arms of the spring element can additionally be latched in order to clamp, for example, the functional layer defined relative to the chamber.

In a very preferred embodiment of the invention, the locking elements for fixing the chamber are designed so that a defined orientation is determined and a faulty installation is avoided (Poka-Yoke principle). For this purpose, the latching elements preferably have different widths or else the latching arms of the spring are arranged at suitable angular positions relative to each other (in the case of three arms, therefore, at least two different-sized angles are included by the arms).

Alternatively, though less preferably, the chamber may be adhered to the decorative support surface by placing an adhesive on the functional surface in the regions surrounding the opening.

Several of the switching elements described above may be arranged adjacent to each other. It is possible that the chambers of the switching elements are individually equipped with functional layers. In a preferred embodiment, a spring element is used to define a plurality of chambers of adjacent switching elements on a decor carrier surface.

Brief description of the drawings

1 shows schematically the structure of a surface-integrated switching element of the prior art;

2 shows a first schematic sectional view of a switching element according to the invention;

3 shows a second schematic sectional view of a switching element according to the invention; and

4 shows a third schematic sectional view of a switching element according to the invention.

Detailed description of the drawings

At the in 1 In a schematic sectional view of the surface-integrated switching element of the prior art is a chamber 10 limited by side walls 101 and a functional interface 102 behind a decor carrier surface 20 arranged. Inside the chamber 10 there is a functional layer 13 , which is designed as a pressure-sensitive sensor. The functional layer 13 is by a spring element 15 relative to the functional surface 102 biased.

In the chamber 10 may be further functional layers, not shown, such as optical fiber layers, located in front of or behind the pressure-sensitive sensor having functional layer 13 can be arranged. Likewise, light sources can be arranged in the chamber, which serve for the backlighting of the switching element. So that the light emitted by the light sources through the decor carrier surface 20 is perceptible, both the decorative support surface 20 , as well as the functional interface 102 be transparent or at least translucent designed. In order to avoid that the radiation emitted by the light source couples into adjacent switching elements and causes a false illumination in these, the side walls are 101 the chamber 10 opaque designed. The production of the chamber 10 for example, via a two-component injection molding process.

The chamber 10 comes with the decor carrier surface 20 connected via an adhesive layer. The adhesive layer must also be transparent or translucent.

2 shows a first embodiment of a surface integrated switching element according to the invention 1 in a schematic sectional view.

The switching element has a chamber 10 on, in which a functional layer 13 is arranged with a pressure-sensitive sensor. In this embodiment, the pressure-sensitive sensor is a film which is coated with a piezoactive material. A slight deformation of the film by a few micrometers causes electrons to be generated within the piezoactive material which can be detected as a voltage signal from an electronic evaluation unit (not shown) connected to the sensor and interpreted as a switching signal. The deformation of the film or functional layer 13 can by a finger of an operator on the decorative layer ( 23 ) on the decor carrier surface 20 in the area of the functional surface 102 the chamber 10 exerted pressure. Here, the functional surface points 102 the chamber 10 an opening 103 on, in which a pressure piece 203 is arranged. The pressure piece 203 is integral with the decor carrier surface in this embodiment 20 executed and penetrates the opening 103 such that the pressure applied by the operator from the pressure piece 203 to the functional layer 13 is forwarded and a deformation of the functional layer 13 caused, between the pressure piece 203 and the functional layer 13 is still a light guide 14 arranged. The light-guiding foil 14 This is done by one in the chamber 10 arranged light source (not shown) emitted light in the direction of the transparent decorated decor carrier surface 20 redirect.

The light-guiding foil 14 and the functional layer 13 be in the mounting position via a spring element 15 against the pressure piece 203 and thus against the decorative support surface 20 biased. By this bias in the mounting position, the tolerances occurring in the manufacture of the individual components can be minimized.

The chamber 10 is arranged with a behind the decorative support surface and associated with this opaque backing layer 21 connected via a locking connection. This is indicated by the chamber 10 on its outer circumference detents in the form of latching hook, which with corresponding locking receptacles in the carrier layer 21 keep in touch.

Because of the pressure piece 203 the opening 103 the functional interface 102 protrudes, ie the layer thickness of the pressure piece 203 greater than the maximum layer thickness of the functional surface 102 , the chamber can 10 when locking with the carrier layer 21 be overprinted, ie the functional layer 13 is opposite the decor carrier surface 20 biased.

A second embodiment of a switching element according to the invention 1 shows 3 , also in a schematic sectional view. Unlike the in 2 illustrated embodiment is the pressure piece 203 executed in this embodiment as a separate component in the form of a small plate. Such components can be inexpensively pre-produced in large quantities. The pressure piece 203 is in the in the functional interface 102 provided opening 103 arranged. A spring element 15 serves to preload the functional layer 13 opposite the decor carrier surface 20 and at the same time for fastening the chamber 10 on the decor carrier surface 20 , For this purpose, the spring element 15 three over the circumference of the chamber 10 outstanding arms that serve as a catch and with at the Dekorträgerfläche 20 arranged locking receptacles correspond.

To a functionally correct tension of the functional layer 13 in the chamber 10 to ensure at the points where the arms of the spring element 15 over the circumference of the chamber 10 sticking out in the sidewall 101 the chamber 10 Slots provided, whereby the spring element 15 at least in the direction of the functional layer 13 is displaceable.

4 shows a third embodiment of the surface-integrated switching element according to the invention 1 , The pressure piece 203 is again designed as a separate component in this embodiment and protrudes clearly into the chamber 10 into it. This can be done by one in the chamber 10 arranged light source 18 emitted light laterally in the pressure piece 203 penetration. For deflecting the laterally incoupling light beams (shown by way of example in the figure as arrows) in the direction of the decor carrier surface 20 has the pressure piece 203 embedded scattering particles in the form of hollow glass spheres on which the light rays are reflected accordingly (in the direction of the right region of the illustrated pressure piece 203 ). In addition, optionally, the functional layer 13 facing side of the pressure piece 203 be provided with a surface structure, which also for deflecting the light in the direction of the decorative surface 20 is suitable (left portion of the illustrated pressure piece 203 ). It is also conceivable to dispense with the scattering particles.

Between the functional surface 102 the chamber 10 and the decor carrier surface 20 is in the pressure piece 203 surrounding areas a ring 201 made of a compressible foam. The ring 201 prevents the formation of false noise due to the switching element 1 acting vibrations, for example by a on the switching element 1 arranged haptic.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10359297 A1 [0002]
• DE 102011003512 [0003]

Claims (10)

Surface integrated switching element ( 1 ), in particular for arrangement in an interior trim part of a vehicle, having a decor carrier surface ( 20 ) and at least one on the decor carrier surface ( 20 ) attached chamber ( 10 ) bounded by one or more side walls ( 101 ) and a functional surface ( 102 ) where the functional surface ( 102 ) an opening ( 103 ), and at least one within the chamber ( 10 ) arranged functional layer ( 13 ), which is designed to generate a switching signal, characterized in that between the decor carrier surface ( 20 ) and the functional layer ( 13 ) a pressure piece ( 203 ) is arranged and the pressure piece ( 203 ) and in the opening ( 103 ) is arranged such that the functional layer ( 13 ) opposite the decor carrier surface ( 20 ) is biased. Surface integrated switching element ( 1 ) according to one of the preceding claims, characterized in that the pressure piece ( 203 ) integral with the decor carrier surface ( 20 ) is formed. Surface integrated switching element ( 1 ) according to one of the preceding claims, characterized in that the functional layer ( 13 ) via a spring element ( 15 ) opposite the decor carrier surface ( 20 ) is biased. Surface integrated switching element ( 1 ) according to one of the preceding claims, characterized in that the chamber ( 10 ) on the decor carrier surface ( 20 ) releasably secured, preferably rusted, is. Surface integrated switching element ( 1 ) according to claim 3 and 4, characterized in that the bias of the functional layer ( 13 ) opposite the decor carrier surface ( 20 ) and the attachment of the chamber ( 10 ) on the decor carrier surface ( 20 ) via a spring element ( 15 ) he follows. Surface integrated switching element ( 1 ) according to one of the preceding claims, characterized in that the functional layer comprises a pressure-sensitive sensor, preferably a piezo, an FSR (Force Sensing Resistor) - or MOC (metal over cap) sensor. Surface integrated switching element ( 1 ) according to one of the preceding claims, characterized in that within the chamber ( 10 ) a light source ( 18 ), in particular an LED, is arranged. Surface integrated switching element ( 1 ) according to claim 7, characterized in that the pressure piece ( 203 ) consists of a light-transmissive material. Surface integrated switching element ( 1 ) according to claim 8, characterized in that the pressure piece ( 203 ) is designed such that the light of the arranged in the chamber light source ( 18 ) laterally in the pressure piece ( 203 ) and that of the functional layer ( 13 ) facing side of the pressure piece ( 203 ) has a surface structure and / or the pressure piece has reflective particles which direct the light in the direction of the decor carrier surface ( 20 ) deflect or divert. Surface integrated switching element ( 1 ) according to one of the preceding claims, characterized in that on the chamber ( 10 ) facing away from the decor carrier surface ( 20 ) a decorative layer ( 23 ), wherein the decorative layer ( 23 ) in the region of the opening ( 103 ) is designed to be flooded with light, in particular has a symbolism or a pattern.

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