SWITCH HOUSING FOR CAPACITIVE SWITCHES

Abstract

The switch housing for capacitive switches has an outer contact surface and flat electrode structures which are arranged on the inside and in a position opposite the contact surface and which are placed by two-component injection molding in recessed regions of the housing body injected from a first, electrically non-conductive plastic component by means of a second, electrically conductive plastic component. Preferably, both plastic components are a polycarbonate, the second plastic component containing carbon fibers.

Claims

1. A method of producing a switch housing for capacitive switches having a contact surface by two-component injection molding, a housing body being injected using a first, electrically insulating plastic component, the housing body having recessed regions on the inside in a position opposite the contact surface, and a second, electrically conductive plastic component containing the same base material as the first plastic component being injected into the recessed regions.

2. The method according to claim 1, wherein both plastic components are a polycarbonate and the second plastic component contains carbon fibers.

3. The method according to claim 1, wherein electrode structures are integrally formed by injecting said second, electrically conductive plastic component.

4. A switch housing for capacitive switches, having an outer contact surface and flat electrode structures which are arranged on the inside in a position opposite the contact surface and which are placed by two-component injection molding in recessed regions of the housing body injected from a first electrically non-conductive plastic component by means of a second, electrically conductive plastic component, and wherein the flat electrode structures are configured with integrally formed contact tags which are guided to a contacting block formed integrally on the inside of the housing body

5. The switch housing according to claim 4, wherein both plastic components are a polycarbonate and the second plastic component contains carbon fibers.

8. The switch housing according to claim 4, wherein the flat electrode structures have recessed windows and the contact surface is translucent opposite the recessed windows.

7. The switch housing according to claim 4, wherein the flat electrode structures are configured with integrally formed contact tags which are guided to a contacting block formed integrally on the inside of the housing body.

8. The switch housing according to claim 7, wherein the contacting block has cutouts into which the ends of the contact tags are positioned and form flush contacting surfaces with the surface of the contacting block.

9. The switch housing according to claim 4, wherein cylindrical track supports are formed integrally with the housing body on the inside.

10. A capacitive switch having a switch housing according to claim 4, wherein a circuit board equipped with an evaluation electronics is arranged at the bottom of the switch housing and is electrically connected to the electrode structures.

11. The switch according to claim 10, wherein the circuit board is additionally equipped with luminous elements which illuminate symbols arranged on the contact surface of the switch housing through recessed windows of the electrode structures and through thinned wall regions of the switch housing.

12. The switch according to claim 10, wherein said circuit board comprises light sources that are configured to illuminate a back side of a front of said capacitive switch.

13. The switch according to claim 12, wherein said light sources are light-emitting diodes.

14. The switch according to claim 10, wherein a front of said capacitive switch is provided with symbols which are associated with the available switching functions wherein the symbols are illuminated from the inside of said switch housing.

15. The switch according to claim 14, wherein said symbols are illuminated through windows In said electrode structures.

16. The switch according to claim 10, wherein said electrode structures are configured such that they each surround a corresponding window configured to guide light.

17. The switch according to claim 16, wherein said electrode structures are allocated to capacitive switching portions corresponding to a dedicated switching function.

18. The switch according to claim 16, wherein said electrode structures are connected to a circuit board comprising evaluation electronics and light sources that are configured to radiate light, said light being guided through said window.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Further features and advantages of the invention will become apparent from the description below of an advantageous embodiment and from the drawings to which reference is made and which show:

[0009] FIG. 1 a perspective view of a switch housing prior to the incorporation of electrode structures;

[0010] FIG. 2 the switch housing with the electrode structures inserted;

[0011] FIG. 3 the switch housing with a circuit board placed thereon; and

[0012] FIG. 4 a perspective view of a capacitive switch produced using the switch housing.

DESCRIPTION

[0013] The switch housing for a capacitive switch Is produced in a two-component injection molding process. FIG. 1 shows a generally cuboidal switch housing which is injected using a first, electrically non-conductive plastic component with a view to the inside. The end face of the switch housing generally denoted by 10, which is opposite the inside forms a contact surface of the capacitive switch. On the opposite inside, the corresponding wall is configured with flat cutouts 12. A second, electrically conductive plastic component is incorporated into these cutouts by two-component injection molding. The result is illustrated in FIG. 2. The structures injected using the second plastic component are electrically conductive and have the shape of the electrode structures required for the capacitive switch. These electrode structures 14 have integrally formed contact tags 14a which lead to a contacting block 16a and 16b, respectively, formed integrally on the inside of the housing body. The contacting blocks 16a, 16b have cutouts into which the ends of the contact tags 14a are positioned. The contacting surfaces at the ends of the contact tags 14a are arranged flush in the surface of the contacting blocks 16a, 16b. It can furthermore be seen in FIG. 2 that the electrode structures 14 have recessed windows 18. Cylindrical circuit board supports 20 are furthermore formed integrally on the inside of the housing body 10.

[0014] In the mounted state shown in FIG. 3, a circuit board is placed onto the circuit board supports 20. The tracks of the circuit board 22 comprise contacting regions in a position opposite the contacting blocks 16a, 16b. The connection of the electrode structures 14 with the circuit board is realized by intermediate conductive rubber elements. The circuit board is equipped with the evaluation electronics of the capacitive switch.

[0015] The front side of the completed capacitive switch shown in FIG. 4 is provided with symbols which are associated with the available switching functions. The symbols and letterings are cut out from a coat of paint by a laser beam. Due to the cutouts 12, the material of the switch housing arranged underneath has a reduced wall thickness and is thus well translucent. Due to the light sources arranged on the circuit board 22, in particular light-emitting diodes, the symbols are illuminated through the windows 18 in the electrode structures 14 from the inside of the switch housing.

[0016] A preferred plastic material for the electrically non-conductive first plastic component from which the housing body 10 is injected is polycarbonate. A polycarbonate is also chosen for the second plastic component which has to be electrically conductive, however such a polycarbonate that is electrically conductive by the addition of carbon fibers. Both plastic materials enter into an intimate connection due to the two-component injection molding process. With this method, it is also possible to produce the precise 3-D structures which are required to easily ensure a secure contacting of the electrode structures up to the circuit board in a mass production process. The capacitive switch is well suitable for use in the automotive field due to its robustness, its absence of wear and its corrosion resistance.