TOUCH-SENSITIVE DEVICE AND DETECTION METHOD

• US 20150116274A1
• Filed: 05/10/2013
• Published: 04/30/2015
• Est. Priority Date: 05/11/2012
• Status: Abandoned Application

• Current Assignee: Sensing Electromagnetic Plus Corporation
• Original Assignee: Fondazione Istituto Italiano di Tecnologia
• Inventors: Beccai, Lucia, Levi, Alessandro, Piovanelli, Matteo, Furlan, Silvano, Mazzolai, Barbara
• Application Number:
  US14/400,094
• Publication Number:
  US 20150116274A1
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

The present invention refers to a touch-sensitive detecting device (1) comprising a sensor (10) associated with a control circuit (50), the sensor (10) comprising a layer (5) with at least an interface (6) suitable for defining a detection area (11) for at least one object (51) in contact with said detection area (11), a number N of emitters (15) and a number M of receivers (20) coupled with said layer (5), said N emitters (15) suitable for emitting a beam (Pn) of detection signals (30) at a wavelength in said layer (5) and said M receivers (20) being suitable for receiving at least a detection signal of said beam (Pn) of detection signals (30) emitted by said emitters (15) and for generating an output signal, said layer (5) being transparent at the wavelength of said detection signals (30) emitted by said N emitters (15) and defining a waveguide for said detection signals (30); the control circuit (50) is suitable for associating a subset of M receivers (20) with each of said N emitters (15), and is suitable for activating said N emitters (15) in a predefined sequence and for activating said M receivers (20); the control circuit (50) is also suitable for detecting for each active emitter (15) of the predefined sequence said output signals of said associated subset of receivers (20), for defining a sequence of output signals; the control circuit (50) comprising a processing unit (55) suitable for processing said sequence of output signals for determining at least one signal representative of said at least one object (51) in contact with said detection area (11).

Claims

1. A touch-sensitive detecting device comprising a sensor associated with a control circuit,

said sensor comprising a layer with at least an interface suitable for defining a detection area for at least one object in contact with said detection area, a number N of emitters and a number M of receivers coupled with said layer, said N emitters being suitable for emitting a beam of detection signals at a wavelength in said layer and said M receivers being suitable for receiving at least a detection signal of said beam of detection signals emitted by said emitters and for generating an output signal, said layer being transparent at the wavelength of said detection signals emitted by said N emitters and defining a waveguide for said detection signals, wherein

said emitters and said receivers are arranged alternating with one another along at least one peripheral portion of said detection area;

said control circuit is suitable for associating a subset of M receivers with each of said N emitters;

said control circuit is suitable for actuating said N emitters in a predefined sequence and for activating said subset of M receivers,

said control circuit is also suitable for detecting for each active emitter of said predefined sequence said output signals of said associated subset of receivers to define a sequence of output signals;

said control circuit comprising a processing unit that is suitable for processing said sequence of output signals for determining at least a signal representative of said at least one object in contact with said detection area.

2. The device according to claim 1, wherein said at least one signal representative of said at least one object is a signal suitable for defining a shape and/or a position of said at least one object.

3. The device according to claim 1, wherein said N emitters are individually activated.

4. The device according to claim 1, wherein said sequence of output signals defines a sequence of reference signals for said M receivers.

5. The device according to claim 1, wherein said detection area is adapted to be mapped in a plurality of basic elements, said control circuit being suitable for associating each pair of emitter-receiver, which is activated in an associated manner, a set of said basic elements belonging to a portion of said detection area associating said pair of emitter-receiver to said received of said pair of emitter-receiver.

6. The device according to claim 1, wherein the number of said M receivers that are comprised in each subset associated with each emitter of said predefined sequence is variable over time.

7. The device according to claim 1, wherein the perimeter of said detection area is defined by the arrangement of the N emitters and of the M receivers in said layer.

8. The device according to claim 1, wherein said layer is made of a material deforming when in contact with said at least one object, said processing unit being suitable for processing said sequence of output signals for determining the deformation of said at least one interface and for defining the pressure distribution of said at least one object in contact with said detection area, said at least one signal representative of said at least one object comprising said pressure distribution.

9. A detection method for a touch-sensitive device comprising a sensor controlled by a control circuit comprising a processing unit, said sensor comprising a layer having at least an interface suitable for defining a detection area for at least one object in contact with said detection area, a number N of emitters and a number M of receivers coupled with said layer, each of said N emitters suitable for emitting a beam of detection signals at a wavelength in said layer, said M receivers suitable for receiving at least a detection signal of said beam of detection signals emitted by said N emitters and for generating an output signal, said layer being transparent to the wavelength of said detection signals emitted by said N emitters and suitable for defining a waveguide for said detection signals;

wherein the method comprises;

an association step, wherein said N emitters and said M receivers we associated alternating with one another along at least a peripheral portion of said detection area and wherein each of said N emitters is associated with a subset of said M receivers;

actuating said N emitters in a predefined sequence and actuating said M receivers;

detecting for each active emitter of said predefined sequence said output signals of said associated subset of receivers to define a sequence of output signals,

the method further comprising a reconstruction step wherein said sequence of output signals is processed and compared with a suitable sequence of reference signals for generating at least a signal representative of said at least one object in contact with the detection area.

10. The method according to claim 9, wherein said at least one signal representative of said at least one object is a signal suitable for defining a shape and/or a position of said at least one object.

11. The method according to claim 9, wherein actuating said N emitters is by actuating the N emitters individually.

12. The method according to claim 9, further comprising a first step comprising:

geometric initialization in which said N emitters and said M receivers are activated through said control circuit for automatically determining position and ordering of each of said N emitters and each of said M receivers;

virtualization of said detection area in which said detection area is partitioned in basic elements and each basic element is associated with respective space coordinates.

13. The method according to claim 12, wherein said first step further comprises a calibration of said sensor wherein each pair of emitter-receiver, which is activated in an associated manner during said predefined sequence, is associated with a reference signal so as to define a sequence of reference signals for said M receivers.

14. The method according to claim 12, wherein said first step further comprises a calibration of said sensor wherein each pair of emitter-receiver, which is activated in an associated manner during said predefined sequence, is associated with a reference signal so as to define a sequence of reference signals for said M receivers, the method comprising a spatial correlation which provides for mapping said detection area associating each pair of emitter-receivers, activated in an associated manner, with said basic elements of said virtualization belonging to a portion of said detection area associating said pair of emitter-receivers.

15. The method according to 9, wherein said reconstruction step defines the pressure distribution of said at least one object in contact with said detection area when said layer is made of a flexible material deforming when in contact with said at least one object, said at least a signal representative of said at least one object comprising said pressure distribution.