Touch sensitive film and a touch sensing device

• US 9,395,851 B2
• Filed: 03/07/2011
• Issued: 07/19/2016
• Est. Priority Date: 03/05/2010
• Status: Active Grant

• Current Assignee: Canatu Oy
• Original Assignee: Canatu Oy
• Inventors: Mikladal, Bjorn Friour, Brown, David P., Aitchison, Bradley J.
• Primary Examiner(s): Patel, Kumar
• Assistant Examiner(s): Lam, Vinh
• Application Number:
  US13/582,865
• Publication Number:
  US 20120327004A1
• Time in Patent Office: 1,961 Days
• Field of Search: 345/173, 200/600, 178/18.01
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04102 Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0444 using a single conductive element covering the whole sensing surface, e.g. by sensing the electrical current flowing at the corners
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A capacitive touch sensitive film comprises a conductive layer having a sensing region. According to the present invention, the sheet resistance of the conductive layer in the sensing region is higher than or equal to 3 kΩ.

Claims

1. A touch sensing device, comprising:

a touch sensitive film comprising;

a conductive layer having a sensing region,

wherein a sheet resistance of the conductive layer in the sensing region is higher than or equal to 3 kΩ

/sq, in all directions of the conductive layer, and

wherein the conductive layer, at a macroscopic scale, forms a solid, monolithic and non-oriented structure;

a circuitry configured to

supply an electrical excitation signal to the sensing region of the conductive layer, and

receive an electrical response signal from the sensing region of the conductive layer; and

a processor configured to

process the electrical response signal, and

detect a touch on the basis of the processed electrical response signal,

wherein the processor is further configured to

determine a phase displacement between the response signal and the excitation signal, based on phase angles of the response signal and the excitation signal, and

detect the touch within the sensing region on the basis of the phase displacement,

wherein the sensing region is electrically connected to the circuitry via a plurality of contact regions on the conductive layer, and the contact regions define a borderline encircling the sensing region, and

wherein, as determined in the direction along said borderline, an average distance between centers of the two adjacent contact regions is at least 10 times as large as an average width of the contact regions in the direction.

2. The touch sensing device according to claim 1, wherein the sheet resistance of the conductive layer in the sensing region is in the range of 5 kΩ

/sq to 100 kΩ

/sq.

3. The touch sensing device according to claim 1, wherein the conductive layer extends over the entire sensing region, as a solid structure.

4. The touch sensing device according to claim 1, wherein the sensing region comprises:

at least one first sub-region having a first sheet resistance; and

at least one second sub-region having a second sheet resistance, and

wherein the first sheet resistance and the second sheet resistance are different from each other.

5. The touch sensing device according to claim 1, wherein the conductive layer comprises a high aspect ratio molecular structure (HARMS) network, an oxide or a polymer.

6. The touch sensing device according to claim 1, wherein the touch sensitive film further comprises a flexible structure configured to allow bending of the touch sensitive film.

7. The touch sensing device according to claim 1, wherein the touch sensitive film further comprises a deformable structure configured to allow deforming of the touch sensitive film.

8. The touch sensing device according to claim 1, wherein the touch sensitive film is optically transparent.

9. The touch sensing device according to claim 1, wherein a number and places of the contact regions are determined so that when determining a straight connection line over the sensing region between centers of the contact regions of each pair of the contact regions, there is a plurality of intersections of said connection lines within the sensing region.

10. The touch sensing device according to claim 1, wherein the processor is further configured to generate a haptic feedback signal to be supplied by the circuitry to the touch sensitive film for providing a haptic feedback.

11. The touch sensing device according to claim 10, wherein the conductive layer is further configured to generate the haptic feedback in response to the haptic feedback signal.

12. The touch sensing device according to claim 11, wherein the conductive layer is further configured to generate at least one electromagnetic field based on the haptic feedback to a user.

13. The touch sensing device according to claim 1,

wherein a number and places of the contact regions are determined so that when determining a straight connection line over the sensing region between centers of the contact regions of each pair of the contact regions, connection line intersections are distributed uniformly over the entire sensing region.