Method and device for signal detection

• US 8,884,914 B2
• Filed: 08/24/2011
• Issued: 11/11/2014
• Est. Priority Date: 10/09/2009
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: Chang, Chin-Fu, Lee, Cheng-Han, Tang, Chi-Hao, Ho, Shun-Lung, Lin, Guang-Huei
• Primary Examiner(s): ABDIN, SHAHEDA A
• Application Number:
  US13/216,661
• Publication Number:
  US 20110304585A1
• Time in Patent Office: 1,175 Days
• Field of Search: 345173-174, 345/50, 345/83, 178/18.01, 178/18.6
• US Class Current: 345/174
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G06F 2203/04101 2.5D-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 and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04102 Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04106 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 Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/047 using sets of wires, e.g. crossed wires

Abstract

A method and device for signal detection is disclosed. At least one detection period is predefined for detecting a signal of a signal source, a differential signal of a pair of signal sources, or a dual-differential signal of three signal sources during at least one clock cycle, wherein the detection evades the period of a predictable noise.

Claims

1. A method for signal detection, comprising:

providing a resistor-capacitor (RC) circuit for providing at least one capacitive coupling signal;

receiving a noise synchronizing signal which triggers at least one non-integration period, wherein the RC circuit is affected by a predictable noise in the at least one non-integration period;

providing at least one integration control signal for controlling integration detection on the at least one capacitive coupling signal in a plurality of clock cycles in the at least one non-integration period; and

performing integration detection on the at least one capacitive coupling signal, evading predictable noise, based on the at least one integration control signal; and

pairwisely interchanging signal sources of a pair of inputs in each of at least two subtractors based on the synchronizing signal,

an output of each of the subtractor providing a respective signal difference of the pair of the inputs,

wherein each integration circuit performs integration detection on a signal difference of a pair of outputs in the outputs of each subtractor, respectively.

2. The method of claim 1, wherein the RC circuit is included in a capacitive touch panel.

3. The method of claim 1, wherein the noise synchronizing signal is a common electrode voltage signal of a display, and the at least one non-integration period is edge triggered by the common electrode voltage signal, wherein the predictable noise is emitted by the display.

4. The method of claim 1, wherein the noise synchronizing signal is generated based on a common electrode voltage signal of a display, wherein the predictable noise is emitted by the display.

5. The method of claim 1, wherein when at least one integration circuit encounters the at least one non-integration period triggered by the noise synchronizing signal during the integration detection on the at least one capacitive coupling signal, the integration circuit suspends the integration detection on the at least one capacitive coupling signal in each non-integration period based on at least one integration control signal, and resumes the integration detection on the at least one capacitive coupling signal at the end of each non-integration period.

6. The method of claim 1, wherein the integration control signal is distributed in a plurality of clock cycles, these clock cycles do not include the at least one non-integration period.

7. The method of claim 1, wherein the at least one integration control signal includes:

an enabling signal defining at least one detection period in a clock cycle, wherein at least one integration circuit performs the integration detection on the at least one capacitive coupling signal, evading the predictable noise.

8. A device for signal detection, comprising:

a resistor-capacitor (RC) circuit for providing at least one capacitive coupling signal;

a control circuit, including;

receiving a noise synchronizing signal which triggers at least one non-integration period, wherein the RC circuit is affected by a predictable noise in the at least one non-integration period; and

providing at least one integration control signal for controlling integration detection on the at least one capacitive coupling signal in a plurality of clock cycles in the at least one non-integration period; and

at least one integration circuit for performing integration detection on the at least one capacitive coupling signal, evading predictable noise, based on the at least one integration control signal; and

pairwisely interchanging signal sources of a pair of inputs in each of at least two subtractors based on the synchronizing signal,

an output of each of the subtractor providing a respective signal difference of the pair of the inputs,

wherein each integration circuit performs integration detection on a signal difference of a pair of outputs in the outputs of each subtractor, respectively.

9. The method of claim 8, wherein the RC circuit is included in a capacitive touch panel.

10. The method of claim 8, wherein the noise synchronizing signal is a common electrode voltage signal of a display, and the at least one non-integration period is edge triggered by the common electrode voltage signal, wherein the predictable noise is emitted by the display.

11. The method of claim 8, wherein the noise synchronizing signal is generated based on a common electrode voltage signal of a display, wherein the predictable noise is emitted by the display.

12. The method of claim 8, wherein when the at least one integration control circuit encounters the at least one non-integration period triggered by the noise synchronizing signal during the integration detection on the at least one capacitive coupling signal, the integration control circuit suspends the integration detection on the at least one capacitive coupling signal in each non-integration period based on at least one integration control signal, and resumes the integration detection on the at least one capacitive coupling signal at the end of each non-integration period.

13. The method of claim 8, wherein the integration control signal is distributed in a plurality of clock cycles, these clock cycles do not include the at least one non-integration period.

14. The method of claim 8, wherein the at least one integration control signal includes:

an enabling signal defining at least one detection period in a clock cycle, wherein the at least one integration circuit performs the integration detection on the at least one capacitive coupling signal, evading the predictable noise.