INPUT DEVICE WITH AN ARRAY OF FORCE SENSORS IN A FILM LAYER STRUCTURE WITH IMPROVED DURABILITY AND SIMPLIFIED PRODUCTION

Abstract

The present disclosure relates to an input device and a method of producing the device. The input device includes a flat panel defining an array of control surfaces, a support disposed on a side of the panel facing away from an operator, and a flat film layer structure disposed between the flat panel and the support which defines an array of capacitive sensors; wherein each capacitive sensor forms a measuring capacitance assigned to one of the control surfaces; wherein the support forms at least one web, which protrudes towards the flat panel and connects to the flat panel to fix the film layer structure between the flat panel and the support.

Claims

1. An input device comprising: a flat panel defining an array of control surfaces; a support disposed on a side of the flat panel facing away from an operator; and a film layer structure disposed between the flat panel and the support which defines an array of capacitive sensors; wherein each of the capacitive sensors forms a measuring capacitance assigned to one of the control surfaces; wherein the support forms at least one web, which protrudes towards the flat panel and connects to the flat panel to fix the film layer structure between the flat panel and the support.

2. The input device of claim 1, wherein each of the control surfaces is disposed on a side of the flat panel facing towards an operator and further comprises a backlightable luminous surface.

3. The input device of claim 1, wherein the flat panel further includes: a light-conducting layer covering at least a luminous surface in a connecting manner, and a plurality of lighting means for each control surface for backlighting the associated luminous surface of the control surface while transmitting light through the light-conducting layer.

4. The input device of claim 3, wherein the web is structured such that the end thereof pointing away from the support connect to the light-conducting layer and reach though the film layer structure protruding beyond the film layer structure in the direction of the panel.

5. The input device of claim 1, wherein the web is structured to be in any one of: a flat extent of the flat panel and the support, between the luminous surfaces, and periphery of the support.

6. The input device of claim 3, wherein the web is made from a thermoplastic material, the light-conducting layer is made from a thermoplastic material, and the support is welded to the flat panel.

7. The input device of claim 1, wherein the film layer structure includes plurality of films.

8. The input device of claim 3, wherein the film layer structure is structured to include at least one opaque layer and at least one through-holes for a passage of light from a respective lighting means to the light-conducting layer.

9. The input device of claim 6, wherein the panel has a decorative film that is back-molded with a translucent or transparent thermoplastic material for forming the light-conducting layer.

10. The input device of claim 8, wherein the web is disposed so as to reach through one through-hole, respectively, of the film layer structure.

11. The input device of claim 1, configured for use in a motor vehicle.

12. A method for producing an input device comprising: providing a flat panel defining an array of control surfaces; providing a support on a side of the flat panel facing away from an operator; disposing a film layer structure between the flat panel and the support, wherein the film layer structure defines an array of capacitive sensors, wherein each of the capacitive sensors forms a measuring capacitance assigned to one of the control surfaces; and fastening the flat panel and the support, by connecting at least one web, which protrudes towards the flat panel, to the flat panel to fix the film layer structure between the flat panel and the support.

13. The method of claim 12, further comprising: disposing each control surface on a side of the flat panel facing towards an operator, wherein each control surface includes a backlightable luminous surface.

14. The method of claim 12, wherein the flat panel on a side facing towards the support, further comprises: a light-conducting layer covering at least a luminous surface in a connecting manner, and a plurality of lighting means for each control surface for backlighting the associated luminous surface of the control surface while transmitting light through the light-conducting layer.

15. The method of claim 12, further comprising: producing a web structure on any one of: a flat extent of the flat panel and the support, between the luminous surfaces, and periphery of the support.

16. The method of claim 12, further comprising: producing the support wherein the support is made from a thermoplastic material, and producing the flat panel wherein, the panel is made by back-molding a decorative film with a translucent or transparent thermoplastic material while forming the light-conducting layer, wherein the web is welded to the light-conducting layer when the panel and the support are fastened.

Description

[0026] The present disclosure is explained further with reference to the following Figures. The Figures are to be understood only as examples and merely represent a preferred embodiment. In the Figures:

[0027] FIG. 1 shows a sectional view through an embodiment of the input device according to the present disclosure;

[0028] FIG. 2 shows an associated detailed view;

[0029] FIG. 3 shows a top view of the support of the embodiment of the input device according to the present disclosure shown in FIG. 1, with the film layer structure 4 disposed thereon.

[0030] FIG. 1 shows an embodiment of the input device 1 according to the present disclosure. The input device 1 has an array of control surfaces 20a, 20b, which is formed on a surface, which faces towards the operator, of a flat panel 2 made from a decorative layer 9 and a light-conducting layer 6 which, viewed from the operator's point of view, is situated thereunder. The transparent layer 6 is formed from a translucent or transparent thermoplastic material and, by back-molding the decorative layer 9, is applied thereto substantially across the entire surface and connected therewith. In order to be found more easily or for displaying a switching state if required, the control surfaces 20a, 20b have selectively backlightable luminous surfaces 10a, 10b. For indicating the associated switching function, which is to be activated by the actuation of the control surface 20a, 20b, corresponding symbols are displayed by means of the luminous surfaces 10a, 10b.

[0031] The input device 1 further has a support 3 made from an opaque thermoplastic material, which is disposed on the far side of the panel 2. A film layer structure 4, which defines an array of capacitive force sensors 21a, 21b, is disposed between the panel 2 and the support 3, wherein exactly one of the capacitive force sensors 21a, 21b is assigned to each control surface 20a, 20b. Each of the force sensors 21a, 21b is provided for forming, by means of an evaluation unit that is not shown, a measuring capacitance between the panel 2 and the support 3, which is assigned to one of the control surfaces 20a, 20b. The film layer structure 4, for each force sensor 21, 21b, has at least one first electrode 11a, 11b which is more closely adjacent to the panel 2, and at least one second electrode 12a, 12b, which is more closely adjacent to the support 3, for forming the above-mentioned measuring capacitance. As FIG. 2 shows in detail, the first electrodes 11a, 11b are formed as a metallic coating of the surface of a first film of the film layer structure 4 facing towards the panel 2, whereas the second electrodes 12a, 12b are formed as a metallic coating of the surface of a second film of the film layer structure 4 facing towards the support 3. The film layer structure 4 may have further films or film-like layers. Alternatively, the film layer structure 4 may define an array of capacitive touch sensors. For example, this is a film partially metal-coated on one side, wherein the metallic layers are electrically insulated from one another and serve as electrodes for generating a measuring capacitance. In the embodiment shown in FIG. 1, the film layer structure has an elastically deformable distance layer 9, which is provided between the first film supporting the first electrodes 12a, 12b and the second film supporting the second electrodes 12a, 12b, in order to permit an elastic deformation and thus a reversible convergence of the associated electrode pairs 11a, 12a or 11 b, 12b, and thus a detectable change in the associated measuring capacitance of the capacitive force sensors 21a, 21b, when an actuating force acts on the control surfaces 20a, 20b. On the side of the support 3, one lighting means 5a, 5b is respectively provided for each control surface 20a, 20b, for backlighting the associated luminous surface 10a, 10b associated with the respective control surface 20a, 20b, while transmitting light through a though-hole D provided in the film layer structure 4 and the light-conducting layer 6. The lighting means 5a, 5b are configured in an SMD design and disposed on a circuit board, which is not shown in more detail, on the support 3. A web 7 rises from between the lighting means 5a, 5b. FIG. 3 shows an associated top view of the support 3, which illustrates the structure, from the side of the operator, with the film layer structure 4 disposed on the support 3.

[0032] The web 7 reaches through the through-hole D in the film layer structure 4 and, at the end 8 thereof that faces away from the support and is shown in FIG. 1, is connected by substance-to-substance connection to the light-conducting layer 6 of the panel 2 through ultrasonic welding, in order to fix, on the one hand, the film layer structure 4 between the support 3 and the panel 2 in a clamping manner and, on the other hand, fix the support 3 to the panel 2. The web 7 further reduces the passage of light from one luminous surface 10a to an adjacent luminous surface 10b in order to prevent an undesirable light transfer of the light source 5b to the respective other control surface 20a or 20b.