Capacitive touch sensing

Patent metadata

Field	Value
Publication number	US-9811229-B2
Application number	US-201715449224-A
Country	US
Kind code	B2
Filing date	Mar 3, 2017
Priority date	Nov 14, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A touch sensor apparatus includes a grid of intersecting sensor lines, a plurality of input/output (IO) pins, a plurality of diodes, a processor coupled to the IO pins. More specifically, each intersection includes a capacitor coupling together the intersecting sensor lines. Each diode is coupled to a corresponding IO pin, wherein each IO pin couples through its corresponding diode to a channel of intersection points of the sensor lines and, without the diode, each IO pin couples to a different channel of intersecting points of the sensor lines. The processor is configured to sequentially provide a transmit signal through each IO pin while detecting a response signal on the other IO pins.

First claim

What is claimed is:

1. A touch sensor apparatus, comprising:
a grid of intersecting sensor lines, each intersection including a capacitor coupling together the intersecting sensor lines;
a plurality of input/output (IO) pins; and
a plurality of diodes, each diode coupled to a corresponding IO pin, wherein each IO pin couples through its corresponding diode to a channel of intersection points of the sensor lines and, without the diode, each IO pin couples to a different channel of intersecting points of the sensor lines; and
a processor coupled to the IO pins and configured to sequentially provide a transmit signal through each IO pin while detecting a response signal on the other IO pins.

2. The touch sensor apparatus of claim 1 , wherein the processor is configured to provide a transmit signal through each IO pin and to the channel of the IO pin without the diode, and to receive response signals from the remaining IO pins via channels with diodes.

3. The touch sensor apparatus of claim 1 , wherein the processor is configured to provide a transmit signal through each IO pin and to the channel with the diode of that IO pin, and to receive response signals from the remaining IO pins via channels without diodes.

4. The touch sensor apparatus of claim 1 , wherein each response signal includes an amount of time that the transmit signal takes to charge the capacitor coupling together the sensor line on which the transmit signal is provided and the sensor line through which the response signal is detected to a predefined voltage level.

5. The touch sensor apparatus of claim 4 , further comprising a timer coupled to the processor to measure the amount of time.

6. The touch sensor apparatus of claim 1 , wherein, based on the detected response signal, the processor is configured to calculate a capacitance value of the capacitor coupling together the intersecting sensor lines.

7. A capacitive touch sensing (CTS) controller, comprising:
a plurality of input/output (IO) pins, each IO pin is to couple to first and second sensor lines of a touch sensor, said first and second sensor lines are usable to transmit a first signal and receive a second signal, wherein for each IO pin, the first sensor line is configured to interact with the second sensor lines from the other IO pins;
for each IO pin, a diode is configured to couple to one of the first or second sensor lines; and
a processor coupled to the IO pins, and wherein for each IO pin, the processor is configured to provide the first signal to be transmitted on the first sensor line and, based on each received second signal from another IO pin's second sensor line to calculate a capacitance value.

8. The CTS controller of claim 7 , wherein the processor is configured to transmit the first signal via the first sensor line so as to alter a capacitance value of a capacitor coupled between the first sensor line and each of the corresponding second sensor lines.

9. The CTS controller of claim 7 , wherein the first and second signals are pulse signals.

10. The CTS controller of claim 7 , further comprising a timer coupled to the processor, the timer is configured to measure the amount of time to charge a capacitor between the first sensor line of an IO pin and one of the second sensor lines coupled to the other IO pins.

11. The CTS controller of claim 7 , wherein the diodes and the processor are integrated on a printing circuit board (PCB).

12. A method of detecting a touch point of a touch sensor comprising a grid of sensor lines, some sensor lines usable as transmit sensor lines and the remaining sensor lines usable as receive sensor lines, comprising:
sequentially transmitting a pulse signal via an input/output (IO) pin coupled to each transmit sensor line;
upon transmitting each pulse signal via a given IO pin, detecting a sense signal on the receive sensor lines coupled to all remaining IO pins; and
analyzing each sense signal to determine a capacitance value between the transmit sensor line corresponding to the given IO pin and the receive sensor lines of the remaining IO pins.

13. The method of claim 12 , wherein analyzing each sense signal includes measuring the amount of time to charge a capacitor to a predefined voltage level, the capacitor coupled between the transmit sensor line of the given IO pin and an intersecting receive sensor line of another IO pin.

14. The method of claim 12 , wherein analyzing each sense signal includes digitizing the sense signal.

15. The method of claim 12 , further comprising comparing the determined capacitance value with a fault threshold to detect a presence of a malfunction on a capacitor coupled between a transmit sensor line and intersecting receive sensor line.

Assignees

• Texas Instruments Inc

Inventors

• Yi Zhou
• Jun Zhang
• Ge Shen
• Cheng xu kang
• Meng Hao
• Jun Ji Ru

Classifications

• G06F3/044 Primary

  by capacitive means · CPC title

• G06F3/0416

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06F3/04164 Primary

  Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads · CPC title

• G06F3/0446

  using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes · CPC title

• G06F3/04166

  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 title