Non-linear resistive touch sensor

• US 8,836,647 B2
• Filed: 09/19/2007
• Issued: 09/16/2014
• Est. Priority Date: 09/26/2006
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Alexander, Douglas Ulrich
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): Park, Sanghyuk
• Application Number:
  US12/442,208
• Publication Number:
  US 20090315845A1
• Time in Patent Office: 2,554 Days
• Field of Search: 345173-178
• US Class Current: 345/173
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard

Abstract

A touch sensor has a support layer (12) of an insulating material and a resistive layer (13) applied to the support layer. A resistive material is shaped according to an elongated pattern forming a sequence of touch positions, and has a single terminal (16) to be coupled to a sense input (17) of a detecting device (11), while an open end (15) of the sequence opposite to the terminal end remains unconnected. The detecting device detects an active resistance (R_p) between the single terminal and one of said touch positions that is touched by a user via a return capacitance constituted (C_u) by the user and a mass element (18) coupled to the detecting device. Advantageously only a single terminal is necessary, whereas a number of touch positions can be discriminated.

Claims

1. A touch sensor comprising:

a foldable support layer of an insulating material and a single flexible resistive layer applied to the support layer, wherein the flexible support layer is a single layer of flexible material onto which the flexible resistive layer is applied,

the single flexible resistive layer being constituted by a resistive material shaped according to an elongated pattern forming a sequence of touch positions, and the elongated pattern having, at a connectable end of the sequence, a single terminal arranged to be coupled to a sense input of a detecting device, while an open end of the sequence opposite to the connectable end of the sequence remains unconnected, wherein a difference in resistive value between adjacent touch positions increases more than a resistive value that increases proportional to a distance to the single terminal, wherein intermediate sections between subsequent touch areas have one of;

increasing lengths and decreasing widths;

the detecting device being arranged to detect an active resistance (R_P) between the single terminal and one of said touch positions that is touched by a user via a return capacitance constituted (C_U) by the user and a mass element coupled to the detecting device; and

the detecting device being arranged to calibrate the touch sensor by requesting that a user touch at least two different touch positions from the sequence of touch positions.

2. The touch sensor as claimed in claim 1, wherein the single flexible resistive layer is shaped according to the elongated pattern in which the active resistance (R_P) increases more than proportional to the distance to the single terminal.

3. The touch sensor as claimed in claim 1, wherein the single flexible resistive layer is shaped according to the elongated pattern having a discrete number of touch areas.

4. The touch as claimed in claim 3, wherein the single flexible resistive layer is shaped according to the elongated pattern having relatively broad parts at the touch areas and relatively small intermediate parts between the touch areas.

5. The touch sensor as claimed in claim 3, wherein the single flexible resistive layer is shaped according to the elongated pattern having a resistance difference between each subsequent touch area, and is arranged to have the resistance differences increase towards the open end.

6. The touch sensor as claimed in claim 1, wherein the single flexible resistive layer is shaped according to the elongated pattern to constitute at least part of:

a user interface for a mobile device, in particular a mobile phone, a media player or a personal digital assistant, a user interface for an electronic device, in particular a keyboard or touch sensitive display.

7. A method of manufacturing a touch sensor, the method comprising the steps of:

providing a foldable support layer of an insulating material;

applying a single flexible resistive layer to the support layer, wherein the support layer is a single layer of flexible material onto which the single flexible resistive layer is applied,

the single flexible resistive layer constructed by shaping a resistive material according to an elongated pattern forming a sequence of touch positions, wherein a difference in resistive value between adjacent touch positions increases more than a resistive value that increases proportional to a distance to the single terminal, wherein intermediate sections between subsequent touch areas have one of;

increasing lengths and decreasing widths, and

providing, at a connectable end of the sequence, a single terminal arranged to be coupled to an input of a detecting device, while an open end of the sequence opposite to the connectable end of the sequence remains unconnected,

the detecting device being arranged to detect a resistance between the single terminal and one of said touch positions that is touched by a user via a return capacitance constituted by the user and a mass element coupled to the detecting device, and

the detecting device being arranged to calibrate the touch sensor by requesting

that a user touch at least two different touch positions from the sequence of touch positions.

8. The method as claimed in claim 7, wherein the method comprises at least one of:

a step of shaping a resistive material according to the elongated pattern and attaching the shaped resistive material to the single flexible support layer;

a step of printing a resistive pattern on the single flexible support layer;

a step of embedding the resistive material in textile by inserting resistive threads.

9. A detecting device for cooperating with a touch sensor that comprises:

a foldable support layer of an insulating material, and

a single flexible resistive layer applied to the single flexible support layer,

wherein the support layer is a single layer of flexible material onto which the flexible resistive layer is applied

the single flexible resistive layer being constituted by a resistive material shaped according to an elongated pattern forming a sequence of touch positions, and the elongated pattern having, at a connectable end of the sequence,

a single terminal arranged to be coupled to a sense input of a detecting device, while an open end of the sequence opposite to the connectable end of the sequence remains unconnected, wherein a difference in resistive value between adjacent touch positions increases more than a resistive value that increases proportional to a distance to the single terminal, wherein intermediate sections between subsequent touch areas have one of;

increasing lengths and decreasing widths,

the detecting device being arranged to detect a resistance between the sense input and one of said touch positions that is touched by a user via a return capacitance constituted by the user and a mass element coupled to the detecting device, and

the detecting device being arranged to calibrate the touch sensor by requesting that a user

touch at least two different touch positions from the sequence of touch positions.

10. The detecting device as claimed in claim 9, wherein the device comprises at least one of:

a frequency generating circuit coupled to the sense input for detecting a frequency in dependence of the active resistance;

an impedance detecting circuit coupled to the sense input for detecting an impedance in dependence of the active resistance.