SWITCHED-ELECTRODE CAPACITIVE-MEASUREMENT DEVICE FOR TOUCH-SENSITIVE AND CONTACTLESS INTERFACES

• US 20140267165A1
• Filed: 12/18/2012
• Published: 09/18/2014
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: Quickstep Technologies, LLC (Broadcom, Inc.)
• Original Assignee: Nanotec Corporation
• Inventors: Roziere, Didier
• Granted Patent: US 9,250,757 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

The present invention relates to a capacitive-measurement device for touch-sensitive and/or contactless interfaces, including at least one capacitive-measurement electrode (1) and electrode-switching unit (2) capable of electrically connecting the at least one electrode (1), either to a capacitive-measurement unit or to a guard potential (11), the at least one capacitive-measurement electrode (1) and the electrode-switching unit (2) being provided on a single detection surface (7) according to a technique for manufacturing planar electronic components. The invention also relates to an apparatus implementing the device.

Claims

1. Capacitive measurement device for touch-sensitive and/or contactless interfaces comprising at least one capacitive measurement electrode (1) and means of electrode switching (2) capable of electrically connecting said at least one electrode (1) either to capacitive measurement means (27) or to a guard potential (11), characterized in that said at least one capacitive measurement electrode (1) and said means of electrode switching (2) are produced on a single detection surface (7) according to a manufacturing technique for electronic components of planar type.

2. Device according to claim 1, which comprises moreover:

a plurality of capacitive measurement electrodes (1) distributed over a detection surface (7) according to a two-dimensional structure with two intersecting directions (X, Y),

means of electrode switching (2) placed nearby said measurement electrodes (1) on the detection surface (7),

first electrical connection tracks (5) arranged on the detection surface (7) in such a way as to be capable of connecting to the capacitive measurement means (27) via their respective means of electrode switching (2), a plurality of measurement electrodes (1) distributed approximately in a first direction (X), and

second electrical connection tracks (6) arranged on the detection surface (7) in such a way as to be capable of connecting at a switching signal the respective means of electrode switching (2) of a plurality of measurement electrodes (1) distributed approximately in the second direction (Y).

3. Device according to claim 1, which comprises moreover a guard plane (15) in an appreciably electrically conductive material, at the electrical guard potential (11), arranged below the measurement electrodes (1) and separated from said electrodes (1) by at least one layer of an appreciably electrically insulating material (12).

4. Device according to claim 3, which comprises moreover means of electrode switching (2) connected electrically to the guard plane (15) by electrical connections (14) passing through the layer(s) of appreciably insulating material (12).

5. Device according to claim 1 of in which the means of electrode switching (2) comprise two transistors (3, 4), of which a first transistor (3) is capable of connecting a measurement electrode (1) to the capacitive measurement means (27) and a second transistor (4) is capable of connecting said measurement electrode (1) to the guard potential (11), which transistors (3, 4) are controlled by a switching signal such that when one is on-state the other is off-state.

6. Device according to claim 5, which comprises moreover transistors (3, 4) produced according to a thin layer deposition technology.

7. Device according to claim 5, which comprises moreover transistors (3, 4) which are substantially transparent.

8. Device according to claim 5, which comprises moreover transistors (3, 4) of one of the following types:

TFT type field-effect transistor,

OFET type transistors based on organic semiconductors.

9. Device according to claim 1 which is produced in such a way as to be substantially transparent.

10. Device according to claim 1 which comprises at least one element among measurement electrodes (1), a guard plane (15) and tracks (5, 6) comprising ITO.

11. Device according to claim 1, which comprises moreover second switching means (20) capable of connecting the means of electrode switching (2), either to capacitive measurement means (27), or to a guard potential (11).

12. Device according to claim 1 of which comprises moreover capacitive measurement means (27) at least in part referenced to a reference electrical potential (11) which is floating with respect to earth potential (23).

13. Device according to claim 12, in which the reference electrical potential is approximately equal to the guard potential (11).

14. Human-machine interface device comprising a command interface (10) and a capacitive measurement device according to claim 1.

15. Human-machine interface device according to claim 14 which comprises a command interface (10) equipped with a display screen, and a capacitive measurement device which is substantially transparent.

16. Device of one of the following types:

smartphone, tablet, display screen, computer, control pad for a machine or vehicle, comprising a human-machine interface device according to claim 14.

17. Device according to claim 2, which comprises moreover a guard plane (15) in an appreciably electrically conductive material, at the electrical guard potential (11), arranged below the measurement electrodes (1) and separated from said electrodes (1) by at least one layer of an appreciably electrically insulating material (12).

18. Device according to claim 2 in which the means of electrode switching (2) comprise two transistors (3, 4), of which a first transistor (3) is capable of connecting a measurement electrode (1) to the capacitive measurement means (27) and a second transistor (4) is capable of connecting said measurement electrode (1) to the guard potential (11), which transistors (3, 4) are controlled by a switching signal such that when one is on-state the other is off-state.

19. Device according to claim 3 in which the means of electrode switching (2) comprise two transistors (3, 4), of which a first transistor (3) is capable of connecting a measurement electrode (1) to the capacitive measurement means (27) and a second transistor (4) is capable of connecting said measurement electrode (1) to the guard potential (11), which transistors (3, 4) are controlled by a switching signal such that when one is on-state the other is off-state.

20. Device according to claim 4 in which the means of electrode switching (2) comprise two transistors (3, 4), of which a first transistor (3) is capable of connecting a measurement electrode (1) to the capacitive measurement means (27) and a second transistor (4) is capable of connecting said measurement electrode (1) to the guard potential (11), which transistors (3, 4) are controlled by a switching signal such that when one is on-state the other is off-state.