TOUCH SENSOR

• US 20090315845A1
• Filed: 09/19/2007
• Published: 12/24/2009
• Est. Priority Date: 09/26/2006
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Alexander, Douglas Ulrich
• Granted Patent: US 8,836,647 B2
• Time in Patent Office: Days
• 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. Touch sensor comprising a support layer (12) of an insulating material and a resistive layer (13) applied to the support layer,

the 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 (14) of the sequence, a single terminal (16) arranged to be coupled to a sense input (17) of a detecting device (11), while an open end (15) of the sequence opposite to the connectable end of the sequence remains unconnected,

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 (18) coupled to the detecting device.

2. Touch sensor as claimed in claim 1, wherein the resistive layer (13) 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. Touch sensor as claimed in claim 1, wherein the resistive layer (13) is shaped according to the elongated pattern having a discrete number of touch areas.

4. Touch sensor as claimed in claim 3, wherein the resistive layer (13) 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. Touch sensor as claimed in claim 3, wherein the resistive layer (13) 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. Touch sensor as claimed in claim 1, wherein the resistive layer (13) 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. Method of manufacturing a touch sensor, the method comprising the steps of:

providing a support layer of an insulating material;

applying a resistive layer to the support layer,

and, for constituting the resistive layer, shaping a resistive material according to an elongated pattern forming a sequence of touch positions, 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.

8. 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 support layer;

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

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

9. Detecting device for cooperating with a touch sensor that comprises a support layer of an insulating material and a resistive layer applied to the support layer,

the 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,

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.

10. 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