Enhancing sensitivity and robustness of mechanical rotation and position detection with capacitive sensors

Patent metadata

Field	Value
Publication number	US-10288658-B2
Application number	US-201815886173-A
Country	US
Kind code	B2
Filing date	Feb 1, 2018
Priority date	Feb 2, 2017
Publication date	May 14, 2019
Grant date	May 14, 2019

Abstract

Described example user interface control apparatus includes a first structure, with a first side, conductive capacitor plate structures spaced along a first direction on the first side, a movable second structure with an auxiliary conductive structure, and an interface circuit to provide excitation signals to, and receive sense signals from, the conductive capacitor plate structures to perform a mutual capacitance test and a self-capacitance test of individual ones of the conductive capacitor plate structures to determine a position of the second structure or a user's finger relative to the first structure along the first direction.

First claim

What is claimed is:

1. A control apparatus for a user interface, comprising:
a first structure, including a plurality of conductive capacitor plate structures spaced from one another along a first direction on a first side of the first structure;
a second structure movable relative to the first structure along the first direction, the second structure including a second side facing the first side of the first structure, and an auxiliary conductive structure positioned on the second side of the second structure to move along the first direction to selectively modify a capacitance associated with a given one of the conductive capacitor plate structures when the auxiliary conductive structure is positioned proximate the given one of the capacitor plate structures; and
an interface circuit to provide excitation signals to the conductive capacitor plate structures and receive sense signals from the conductive capacitor plate structures to perform a mutual capacitance test of groups of the conductive capacitor plate structures and to perform a self-capacitance test of individual ones of the conductive capacitor plate structures to provide a position signal that represents a position of the second structure or a user's finger relative to a position of the first structure along the first direction according to signals from the conductive capacitor plate structures during one of the mutual capacitance test and the self-capacitance test.

2. The control apparatus of claim 1 , wherein:
the conductive capacitor plate structures are spaced from one another by a first distance along the first direction;
the first structure further includes:
a second side opposite to the first side; and
a further conductive structure on the second side, the further conductive structure being spaced from the conductive capacitor plate structures by a second distance along a second direction; and

the auxiliary conductive structure is spaced from the conductive capacitor plate structures by a third distance along the second direction.

3. The control apparatus of claim 2 , wherein:
the second distance is greater than the first distance; and
the first distance is greater than the third distance.

4. The control apparatus of claim 3 , wherein the interface circuit is configured to provide an excitation signal to the given one of the conductive capacitor plate structures and to receive a sense signal from a neighboring conductive capacitor plate structure to perform the mutual capacitance test of the groups of the conductive capacitor plate structures.

5. The control apparatus of claim 4 , wherein the interface circuit is configured to provide the excitation signal to the given one of the conductive capacitor plate structures, receive a sense signal from the given one of the conductive capacitor plate structures, and control a voltage of the neighboring conductive capacitor plate structure to perform the self-capacitance test of the given one of the conductive capacitor plate structures.

6. The control apparatus of claim 5 , wherein:
the interface circuit is configured to provide the excitation signal to the given one of the conductive capacitor plate structures, receive the sense signal from the given one of the conductive capacitor plate structures, and set the voltage of the neighboring conductive capacitor plate structure to a first voltage value to perform a first self-capacitance test of the given one of the conductive capacitor plate structures; and
the interface circuit is configured to provide the excitation signal to the given one of the conductive capacitor plate structures, receive the sense signal from the given one of the conductive capacitor plate structures, and allow the neighboring conductive capacitor plate structure to float to perform a second self-capacitance test of the given one of the conductive capacitor plate structures.

7. The control apparatus of claim 5 , wherein:
the interface circuit is configured to provide the excitation signal to the given one of the conductive capacitor plate structures, receive the sense signal from the given one of the conductive capacitor plate structures, and set the voltage of the neighboring conductive capacitor plate structure to a first voltage value to perform a first self-capacitance test of the given one of the conductive capacitor plate structures; and
the interface circuit is configured to provide the excitation signal to the given one of the conductive capacitor plate structures, receive the sense signal from the given one of the conductive capacitor plate structures, and set the voltage of the neighboring conductive capacitor plate structure to a second voltage value to perform a second self-capacitance test of the given one of the conductive capacitor plate structures.

8. The control apparatus of claim 1 , wherein the interface circuit is configured to provide an excitation signal to the given one of the conductive capacitor plate structures, receive a sense signal from the given one of the conductive capacitor plate structures, and control a voltage of a neighboring conductive capacitor plate structure to perform the self-capacitance test of the given one of the conductive capacitor plate structures.

9. The control apparatus of claim 8 , wherein:
the interface circuit is configured to provide the excitation signal to the given one of the conductive capacitor plate structures, receive the sense signal from the given one of the conductive capacitor plate structures, and set the voltage of the neighboring conductive capacitor plate structure to a first voltage value to perform a first self-capacitance test of the given one of the conductive capacitor plate structures; and
the interface circuit is configured to provide the excitation signal to the given one of the conductive capacitor plate structures, receive the sense signal from the given one of the conductive capacitor plate structures, and allow the neighboring conductive capacitor plate structure to float to perform a second self-capacitance test of the given one of the conductive capacitor plate structures.

10. The control apparatus of claim 8 , wherein:
the interface circuit is configured to provide the excitation signal to the given one of the conductive capacitor plate structures, receive the sense signal from the given one of the conductive capacitor plate structures, and set the voltage of the neighboring conductive capacitor plate structure to a first voltage value to perform a first self-capacitance test of the given one of the conductive capacitor plate structures; and
the interface circuit is configured to provide the excitation signal to the given one of the conductive capacitor plate structures, receive the sense signal from the given one of the conductive capacitor plate structures, and set the voltage of the neighboring conductive capacitor plate structure to a second voltage value to perform a second self-capacitance test of the given one of the conductive capacitor plate structures.

11. The control apparatus of claim 1 , wherein the interface circuit is configured to provide an excitation signal to the given one of the conductive capacitor plate structures and to receive a sense signal from a neighboring conductive capacitor plate structure to perform the mutual capacitance test of the groups of the conductive capacitor plate structures.

12. The control apparatus of claim 1 , wherein the first direction is circumferential relative to an axis.

13. The control apparatus of claim 1 , wherein the first direction is linear.

14. The control apparatus of claim 1 , further comprising:
an integer number N optical sources positioned on

Assignees

• Texas Instruments Inc

Inventors

• Spevak Peter

Classifications

• G01R31/64

  Testing of capacitors · CPC title

• G06F3/0383

  Signal control means within the pointing device · CPC title

• G01N27/24

  Investigating the presence of flaws · CPC title

• G09G2320/029

  by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel · CPC title

• G01N27/228

  Circuits therefor (measuring capacitance per se G01R27/26) · CPC title