Pressure-sensitive capacitive measurement device and method for touch-sensitive and contactless interfaces

• US 10,396,784 B2
• Filed: 12/18/2012
• Issued: 08/27/2019
• Est. Priority Date: 12/21/2011
• Status: Expired due to Fees

• Current Assignee: Quickstep Technologies, LLC (Broadcom, Inc.)
• Original Assignee: Quickstep Technologies, LLC (Broadcom, Inc.)
• Inventors: Roziere, Didier
• Primary Examiner(s): Dunlap, Jonathan M
• Application Number:
  US14/368,019
• Publication Number:
  US 20140360854A1
• Time in Patent Office: 2,443 Days
• Field of Search: 345174, 345173, 345156, 324688, 324658, 324661, 324662, 324686
• CPC Class Codes: G01L 1/04 by measuring elastic deformation of gauges, e.g. of springs
• CPC Class Codes: G01L 1/14 by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
• 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 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2017/9613 using two electrodes per touch switch
• CPC Class Codes: H03K 2217/0027 Measuring means of, e.g. currents through or voltages across the switch
• CPC Class Codes: H03K 2217/960765 Details of shielding arrangements
• CPC Class Codes: H03K 2217/96077 comprising an electrode which is floating

Abstract

A capacitive measurement device for control interfaces, includes: (i) a support plate (2) having elements for attachment (4) to a control interface (3), (ii) first electrodes (5) arranged on a first surface of the support plate (2) opposite the control interface (3) and including first active electrodes (5), (iii) electronic capacitive measurement elements capable of enabling the obtainment of proximity and/or contact information of objects of interest (1), and (iv) second electrodes (6, 7) arranged on a second surface of the support plate (2) facing the control interface (3) and including second active electrodes (6) connected to the electronic capacitive measurement elements such as to enable the obtainment of measurements of movement and/or deformation of the support plate (2). A method and apparatus implemented in the device are also described.

Claims

1. A capacitive measurement device, comprising:

a support plate made from a dielectric material, with a resilient material coupled to the support plate and configured for fixing the support plate onto a display referenced to a ground potential,

first active electrodes made from an electrically conductive material, arranged on a first face of said support plate opposite the display and configured to receive a first potential different from the ground potential, wherein each of a plurality of the first active electrodes formed on a central area of the support plate are configurable for individually detecting an approach or contact of one or more objects of interest,

an electronic capacitive measurement amplifier configured for allowing data on the approach or contact of the one or more objects of interest to be obtained by measurements of capacitive coupling with said first active electrodes, and

second active electrodes made from an electrically conductive material, arranged on a second face of said support plate toward the display and configured to receive a second potential, the second active electrodes selectively connectable to said electronic capacitive measurement amplifier so as to allow measurements of one or both of a displacement and deformation of said support plate to be obtained by measurement of capacitive coupling between said second active electrodes and said display,

wherein the electronic capacitive measurement amplifier is configurable for receiving a guard potential at a first input,

wherein the electronic capacitive measurement amplifier is selectively couplable to the first active electrodes at a second input for generating the first potential, or to the second active electrodes at the second input for generating the second potential, and

wherein the first and second potentials are referenced to the guard potential through the electronic capacitive measurement amplifier.

2. The device of claim 1, further comprising one or more guard electrodes configured for receiving the guard potential, the guard potential held at the first potential and different from the ground potential, said one or more guard electrodes being arranged so as to electrically shield, respectively, on their face oriented toward the support plate, the first active electrodes.

3. The device according to claim 2, further comprising plurality of switches configured for connecting either the first active electrodes or the second active electrodes, to the electronic capacitive measurement amplifier or to the guard potential.

4. The device of claim 2, wherein the electronic capacitive measurement amplifier is at least partially referenced to the guard potential.

5. The device of claim 4, in which the first potential is equal to the guard potential.

6. The device of claim 1, wherein the electronic capacitive measurement amplifier is configured for obtaining data on the approach or the contact of the one or more objects of interest by capacitance measurements between each of the plurality of the first active electrodes and the one or more objects of interest.

7. The device of claim 1, the first active electrodes including excitation electrodes and measurement electrodes, the measurement electrodes configurable for being capacitively coupled to said excitation electrodes, and wherein the electronic capacitive measurement amplifier is configurable for obtaining data on the approach or the contact of the one or more objects of interest by measurements of the variation of coupling capacitance between said excitation and measurement electrodes.

8. The device of claim 1, wherein the electronic capacitive measurement amplifier is configurable for obtaining measurements of one or both of the displacement and deformation of said support plate by measurements of capacitance between said second active electrodes and said display.

9. A human-machine interface device comprising the display and the electronic capacitive measurement amplifier according to claim 1.

10. The human-machine interface device according to claim 9 wherein the display is provided with a display screen, and the electronic capacitive measurement amplifier is coupled to the support plate and the first active electrodes which are transparent.

11. A device of one of the following types:

smartphone, tablet, display screen, computer, control pad for a machine or vehicle, comprising the human-machine interface device according to claim 9.

12. A capacitive measurement method, utilizing (i) a support plate made from a dielectric material with a resilient material coupled to the support plate and configured for fixing onto a display referenced to ground potential, (ii) first active electrodes made from a material that is electrically conductive, arranged on a first face of said support plate opposite the display, said first active electrodes configured to receive a first potential different from the ground potential, wherein each of a plurality of the first active electrodes formed on a central area of the support plate are configurable for individually detecting an approach or contact of one or more objects of interest, and (iii) an electronic capacitive measurement amplifier, the method comprising:

obtaining data on the approach or contact of the one or more objects of interest by measurement of capacitive coupling with said first active electrodes,

obtaining measurements of one or both of a displacement and deformation of said support plate by measurements of capacitive coupling between second active electrodes and said display, said second active electrodes (i) made from a material that is electrically conductive, arranged on a second face of said support plate toward the display and (ii) receiving a second potential and being selectively connectable to said electronic capacitive measurement amplifier,

receiving a guard potential at a first input of the electronic capacitive measurement amplifier,

selectively coupling a second input of the electronic capacitive measurement amplifier to the first active electrodes for generating the first potential, or to the second active electrodes for generating the second potential, and

referencing the first and second potentials to the guard potential through the electronic capacitive measurement amplifier.

13. The method of claim 12, further comprising:

connecting the first active electrodes to the electronic capacitive measurement amplifier, and connecting the second active electrodes to the guard potential by plurality of switches,

obtaining data on the approach or the contact of the one or more objects of interest.

14. The method of claim 12, further comprising:

connecting the second active electrodes to the electronic capacitive measurement amplifier, and connecting the first active electrodes to the guard potential by a plurality of switches,

obtaining data on one or both of the displacement and deformation of the support plate.

15. The method of claim 12, further comprising:

obtaining data on the approach or the contact of the one or more objects of interest, and

when at least one object of interest is at a distance less than a predetermined distance, or in contact with at least one of the first active electrodes, obtaining data on one or both of the displacement and deformation of the support plate.

16. The method of claim 12, further comprising determining one or both of a pushing force and a pressure from data on one or both of the displacement and deformation of the support plate.

17. A device of one of the following types:

smartphone, tablet, display screen, computer, control pad for a machine or vehicle, configured for performing the method according to claim 12.