Dual Touch Sensor Architecture With XY-Position And Z-Force Sensing For Touch-On-Surface Button

Patent metadata

Field	Value
Publication number	US-2017269754-A1
Application number	US-201715461419-A
Country	US
Kind code	A1
Filing date	Mar 16, 2017
Priority date	Mar 16, 2016
Publication date	Sep 21, 2017
Grant date	—

Abstract

A dual touch sensor with XY-position and Z-force sensing, such as for implementing a touch button, includes a touch sensor assembly with: (a) an XY-position sensor (such as capacitive, single ended or differential) including an XY electrode disposed at the backside of the touch surface opposite the button area to define an XY sensing area corresponding to the button area, the XY-position sensor to sense a touch within the XY sensing area, as a button-touch event; and (b) a Z-force sensor (such as inductive or capacitive) including a Z-electrode to sense touch-pressure deflection of the touch surface, including to sense a touch-pressure deflection that exceeds a button-press threshold as a button-press event. Sensor electronics coupled to the XY-position sensor and the Z-force sensor detects, as a button touch-press condition, the capacitive XY-position sensor sensing a button-touch event, substantially contemporaneous with the Z-Force sensor sensing a button-press event.

First claim

1 . A device, comprising
a case, including a touch surface that is deflectable based on touch pressure applied to the touch surface; a button area defined on the touch surface; a touch sensor assembly within the case, including
an XY-position sensor including an XY electrode disposed at the backside of the touch surface opposite the button area to define an XY sensing area corresponding to the button area, the XY-position sensor to sense a touch within the XY sensing area, as a button-touch event;
a Z-force sensor including a Z-electrode to sense touch-pressure deflection of the touch surface, including to sense a touch-pressure deflection that exceeds a button-press threshold as a button-press event;
sensor electronics coupled to the XY-position sensor and the Z-force sensor to detect, as a button touch-press condition, the capacitive XY-position sensor sensing a button-touch event, substantially contemporaneous with the Z-force sensor sensing a button-press event.

2 . The device of claim 1 , wherein the XY sensor comprises one of:
a capacitive XY sensor, including an XY capacitive electrode disposed at the touch surface opposite the button area to define an XY capacitive sensing area corresponding to the button area; and a fingerprint sensor to detect a finger touch at the button area, with or without fingerprint verification.

3 . The device of claim 1 , wherein the Z-Force sensor comprises one of:
an inductive Z-force sensor, including
a Z inductor coil,
a Z conductive target disposed between the Z inductor coil, and the XY capacitive electrode, and
elastic insulator material disposed between the XY capacitive electrode and the Z conductive target, and between the Z conductive target and the Z inductor coil,
such that the touch-pressure deflection of the touch surface causes a corresponding movement of the Z conductive target toward the Z inductor coil; or
a capacitive Z-force sensor, including
a Z conductive target, and
a Z capacitive electrode disposed between the Z conductive target, and the XY capacitive electrode,
elastic insulator material disposed between the XY capacitive electrode and the Z capacitive electrode, and between the Z capacitive electrode, and the Z conductive target,
such that the touch-pressure deflection of the touch surface causes a corresponding movement of the Z capacitive electrode toward the Z conductive target.

4 . The device of claim 1 , wherein
the XY sensor comprises a capacitive XY sensor, including an XY capacitive electrode disposed at the touch surface opposite the button area to define an XY capacitive sensing area corresponding to the button area; and further comprising a differential reference capacitive electrode, co-planar with and adjacent to the XY-position capacitive electrode; the sensor electronics coupled to the XY capacitive electrode and the differential reference capacitive electrode.

5 . The device of claim 4 , wherein the differential reference capacitive electrode is ring-shaped around a substantial portion of the circumference of the XY capacitive electrode.

6 . The device of claim 1 , wherein the surface is a glass display panel.

7 . A device, comprising:
a case; including a touch surface deflectable based on touch pressure applied to the touch surface; a button area defined on the touch surface; a touch sensor assembly within the case, including
a capacitive XY-Position sensor, including
an XY capacitive electrode disposed at a backside of the touch surface opposite the button area to define a projected capacitance XY sensing area substantially coextensive with the button area, and
capacitive sensor electronics coupled to the XY capacitive electrode to capture capacitance measurements, including sensing human body capacitance within the XY capacitive sensing area as a button-touch event, and

an inductive Z-Force sensor, including
a Z inductor coil spaced from the XY capacitive electrode,
a conductive target disposed intermediate the Z inductor coil and the XY capacitive electrode, and
inductive sensor electronics coupled to the Z inductor coil to capture inductance measurements, and

elastic insulator material disposed between the XY capacitive electrode and the conductive target, and between the conductive target and the Z inductor coil, such that the touch-pressure deflection of the touch surface causes a corresponding movement of the Z conductive target toward the Z inductor coil,
the inductive sensor electronics to capture changes in inductance caused by touch-pressure deflection of the touch surface that causes movement of the Z conductive target toward the Z inductor coil, including sensing touch-pressure deflection that exceeds a button-press threshold as a button-press event;
such that a button touch-press condition corresponds to the capacitive sensor electronics sensing a button-touch event, and the inductive sensor electronics substantially contemporaneously sensing a button-press event.

8 . The device of claim 7 , further comprising:
a differential reference capacitive electrode, co-planar with and adjacent to the XY capacitive electrode; the capacitive sensor electronics coupled to the XY capacitive electrode and the differential reference capacitive electrode.

9 . The device of claim 8 , wherein the differential reference capacitive electrode is ring-shaped around a substantial portion of the circumference of the XY capacitive electrode.

10 . The device of claim 7 , wherein the surface is a glass display panel.

11 . A method of touch force sensing suitable for implementing a button defined on a surface of a device, comprising
disposing an XY sensor at a device touch surface opposite a button area corresponding to a button, to define an XY sensing area corresponding to the button area, sensing a human body touch at the XY sensing area as a button-touch event; sensing a touch-pressure deflection of the device surface, including sensing a touch-pressure deflection that exceeds a button-press threshold as a button-press event; signaling a button touch-press condition when the button-touch event and the button-press event are substantially contemporaneously sensed.

12 . The method of claim 11 , wherein the XY sensor comprises one of:
a capacitive XY sensor, including an XY capacitive electrode disposed at the surface opposite the button area to define an XY capacitive sensing area corresponding to the button area; and a fingerprint sensor to detect a finger touch at the button area, with or without fingerprint verification.

13 . The method of claim 11 , wherein sensing a touch-pressure deflection of the device surface is implemented by either:
an inductive Z-Force sensor, including
a Z inductor coil,
a Z conductive target disposed between the Z inductor coil, and the XY capacitive electrode, and
elastic insulator material disposed between the XY capacitive electrode and the Z conductive target, and between the Z conductive target and the Z inductor coil,
such that the touch-pressure deflection of the touch surface causes a corresponding movement of the Z conductive target toward the Z inductor coil; or
a capacitive Z-force sensor, including
a Z conductive target, and
a Z capacitive electrode disposed between the Z conductive target, and the XY capacitive electrode,
elastic insulator material disposed between the XY capacitive electrode and the Z capacitive electrode, and between the Z capacitive electrode, and the Z conductive target,
such that the touch-pressure deflection of the surface causes a corresponding movement of the Z capacitive electrode toward the Z conductive target.

Assignees

• Texas Instruments Inc

Inventors

• Liu Dongtai

Classifications

• G06V40/1306

  non-optical, e.g. ultrasonic or capacitive sensing · CPC title

• H03K17/962 Primary

  Capacitive touch switches · CPC title

• G06V10/12

  Details of acquisition arrangements; Constructional details thereof · CPC title

• G06F3/02

  Input arrangements using manually operated switches, e.g. using keyboards or dials · CPC title

• G06F2203/04106

  Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection · CPC title