Keypad in textiles with capacitive read-out circuit
Input apparatus including at least one textile fabric carrier, at least one flexible, wire-and/or thread-like electrical conductor comprising at least one weft and/or warp thread of the fabric carrier, and at least one electrically conductive, flexible key device which is electrically connected to a key connection of the conductor, wherein the conductor is designed for the connection of an evaluation device.
1. An input apparatus comprising:
at least one textile fabric carrier;
flexible, wire-like and/or thread-like electrical conductors, each comprising at least one weft and/or warp thread of the fabric carrier; and
a plurality of electrically conductive, flexible key devices which are electrically connected to key connections of the conductors, are arranged in linear or in matrix-like fashion, and are in each case electrically connected at crossover points to contact redistribution conductors which run essentially perpendicular to at least one of the conductors and which each comprise at least one electrically conductive weft or warp thread of the fabric carrier;
wherein at least one of the conductors is designed for connection of an evaluation device.
2. The input apparatus as claimed in claim 1 , wherein the key devices comprise conductive silicone adhesive.
3. The input apparatus as claimed in claim 1 , wherein each of the key devices has a key layer whose thickness is small relative to its dimensions in the layer plane and which is areally fixed to the fabric carrier.
4. The input apparatus as claimed in claim 1 , wherein the conductors have electrical insulation, which is locally removed for electrical connection to the key devices.
5. The input apparatus as claimed in claim 1 , wherein the contact redistribution conductors are arranged in a manner spaced apart uniformly from one another in the fabric carrier.
6. The input apparatus as claimed in claim 1 , wherein the evaluation device detects an actuation of at least one of the key devices.
7. The input apparatus as claimed in claim 6 , wherein a first group of key devices is designed as reference key devices and a second group of key devices is designed as input key devices.
8. The input apparatus as claimed in claim 7 , wherein the evaluation device is designed for evaluating electrical potential difference or electrical resistance between one of the input key devices and at least one of the reference key devices.
9. The input apparatus as claimed in claim 7 , wherein the input key devices are connected, by a conductor arranged in the fabric carrier, serially and with high impedance to an input connection of the evaluation device and the reference key devices are connected with low impedance to a reference connection of the evaluation device.
10. The input apparatus as claimed in claim 9 , wherein the evaluation device is designed for detecting an actuation of one of the input key devices by evaluation of the electrical resistance between the input and reference connections.
11. The input apparatus as claimed in claim 6 , wherein the evaluation device is designed for outputting a control signal if it detects an actuation of at least two of the key devices in a predetermined temporal sequence.
12. The input apparatus as claimed in claim 6 , wherein the evaluation device is designed for capacitively detecting an actuation of at least one of the key devices.
13. The input apparatus as claimed in claim 12 , further comprising an electrical shielding device, which is designed for electrically shielding at least one of the key devices from a side of the textile fabric carrier.
14. The input apparatus as claimed in claim 13 , wherein the shielding device is a thin conductive layer arranged spaced apart from and running essentially parallel to the at least one of the key devices.
15. A method for producing an input apparatus comprising the steps of:
providing a textile fabric carrier having flexible, wire-like and/or thread-like electrical conductors, each comprising at least one weft and/or warp thread of the fabric carrier;
electrically connecting a plurality of electrically conductive, flexible key devices to key connections of the conductors such that the key devices are arranged in linear or in matrix-like fashion, and are in each case electrically connected at crossover points to contact redistribution conductors which run essentially perpendicular to at least one of the conductors and which each comprise at least one electrically conductive weft or warp thread of the fabric carrier; and
connecting an evaluation device to at least one of the conductors.
16. The method as claimed in claim 15 , wherein the key devices are fitted using a screen printing method.
17. The method as claimed in claim 15 , wherein electrical insulation of the conductors is locally removed before the step of electrically connecting the key devices.