Multiple stimulation phase determination

Patent metadata

Field	Value
Publication number	US-9606663-B2
Application number	US-20832908-A
Country	US
Kind code	B2
Filing date	Sep 10, 2008
Priority date	Sep 10, 2008
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

Determination of phases of multiple stimulation signals to be simultaneously applied to a touch sensor panel is disclosed. A matrix may be determined that is invertible and has a gain greater than one, where each row of the matrix may represent a single step among multiple steps needed to compute values for generating an image of touch, each column of the matrix may represent a drive line of the touch sensor panel to be stimulated, and each element of the matrix may represent the phase of the stimulation signal to be applied to a particular drive line in a particular step. For each step, stimulation signals having phases in accordance with the matrix elements may be simultaneously applied to the drive lines of the touch sensor panel.

First claim

What is claimed is:

1. A method for determining phases of stimulation signals to be simultaneously applied to a plurality of drive lines of a two-dimensional touch sensor panel, the plurality of drive lines including a first plurality of drive lines, the two-dimensional touch sensor panel comprising a plurality of sensors, each sensor formed from capacitive coupling between one of the plurality of drive lines and one of a plurality of sense lines, to generate a two-dimensional image of touch, comprising:
accessing a memory, the memory storing instructions that contain a plurality of steps to compute values for generating signals to stimulate the first plurality of drive lines, each step of the instructions having a plurality of parameters, each parameter representing a phase of the stimulation signal to be applied to a particular drive line in a particular step, wherein the plurality of steps includes a first and second step;
simultaneously stimulating the first plurality of drive lines with the stimulation signals, the stimulation signals having phases in accordance with the plurality of parameters in the first step;
determining a first sense line value for each sense line of the plurality of sense line, wherein the first sense line values are based on the stimulation signals having phases in accordance with the plurality of parameters corresponding to the first step;
maintaining the stimulation of the first plurality of drive lines with the stimulation signals, wherein the phase of the stimulation signals are set in accordance with the plurality of parameters corresponding to the second step;
determining a second sense line value for each sense line of the plurality of sense lines, wherein the second sense line values are based on the stimulation signals having phases in accordance with the plurality of parameters in the second step; and
generating a value corresponding to a capacitance at each sensor of the two-dimensional touch sensor panel to generate the two-dimensional image of touch from response signals received from the plurality of sense lines of the two-dimensional touch sensor panel during the plurality of steps in response to the stimulation signals, each sensor of the two-dimensional touch sensor panel measuring the capacitance between a drive line and a sense line, wherein the generated values are based on the first and second sense line values of each sense line.

2. The method of claim 1 , wherein each element of the matrix has a value that is selected from a group consisting of −1 to represent a negative phase and +1 to represent a positive phase.

3. The method of claim 2 , wherein those elements of the matrix that are representative of a single step to compute the values for generating the signals to stimulate the drive lines have an imbalance of no more than 50% of values of −1 to values of +1.

4. The method of claim 1 , wherein the instructions provide at least as many steps as there are values to compute for generating the signals to stimulate the plurality of drive lines.

5. The method of claim 1 ,
the stimulation signals, the stimulation signals being formed of a predetermined amplitude and a predetermined waveform.

6. The method of claim 1 , further comprising:
forming the stimulation signals, including
for each stimulation signal, generating a voltage having a predetermined amplitude, a predetermined waveform, and one of the provided phases.

7. The method of claim 6 , wherein the predetermined amplitude is about 4.16V.

8. The method of claim 6 , wherein the predetermined waveform is sinusoidal at a predetermined frequency.

9. The method of claim 6 , wherein each provided phase is either 0° or 180°.

10. The method of claim 1 , wherein stimulating the drive lines comprises:
simultaneously stimulating the drive lines with stimulation signals having phases in accordance with the elements of the row of the matrix represented by that step, and
detecting a response from sense lines of the touch sensor panel to the stimulating of the drive lines.

11. In a system including a two-dimensional sensor panel having a plurality of drive lines, the plurality of drive lines including a first plurality of drive lines, being simultaneously driven with a plurality of stimulation signals having positive and negative phases in a particular distribution and a plurality of sense lines responding to the simultaneously driven stimulation signals, a method for determining the phases of the stimulation signals to be simultaneously applied to drive lines of a two-dimensional touch sensor panel, the method comprising:
accessing a memory, the memory storing instructions that contain a plurality of steps to compute values for generating signals to stimulate the first plurality of drive lines, each step of the instructions having a plurality of parameters, each parameter representing a phase of the stimulation signal to be applied to a particular drive line in a particular step, wherein the plurality of steps includes a first and second step;
for each step in the plurality of steps,
simultaneously stimulating the first plurality of drive lines with the stimulation signals, the stimulation signals having phases in accordance with the plurality of parameters in the first step;

determining a first sense line value for each sense line of the plurality of sense line, wherein the first sense line values are based on the stimulation signals having phases in accordance with the plurality of parameters corresponding to the first step;
maintaining the stimulation of the first plurality of drive lines with the stimulation signals, wherein the phase of the stimulation signals are set in accordance with the plurality of parameters corresponding to the second step;
determining a second sense line value for each sense line of the plurality of sense lines, wherein the second sense line vales are based on the stimulation signals having phases in accordance with the plurality of parameters in the second step; and
generating a value corresponding to a capacitance at each sensor of the two-dimensional sensor panel, each sensor measuring the capacitance formed between one of the plurality of first drive lines and one of the plurality of sense lines, to generate a two-dimensional image of touch from the response detected from the sense lines of the two-dimensional sensor panel for each step of the plurality of steps, wherein the generated values are based on the first and second sense line values of each sense line.

12. The method of claim 11 , further comprising:
computing the values for generating the image of touch based on the elements of the matrix and the detected responses.

13. The method of claim 12 , wherein the computed values are capacitances formed between intersections of the drive lines and the sense lines.

14. The method of claim 13 , further comprising:
storing the capacitances for use in generating the image of touch.

15. A sensing device, comprising:
a two-dimensional sensor panel comprising a plurality of sensors, each sensor formed from capacitive coupling between one of a plurality of drive lines, the plurality of drive lines including a first plurality of drive lines, and one of a plurality of sense lines; and
an integrated circuit coupled to the two-dimensional sensor panel, including
driver logic configured to generate a plurality of stimulation signals to simultaneous stimulate the first plurality of drive lines, the stimulation signals having phases in accordance instructions stored in a memory, the instructions arranged to represent a plurality of parameters, each parameter, each parameter represe

Assignees

• Yousefpor Marduke
• Hotelling Steve Porter
• Apple Inc

Inventors

• Yousefpor Marduke
• Hotelling Steve Porter

Classifications

• G06F3/0416 Primary

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06F3/044

  by capacitive means · CPC title

• G06F3/0446 Primary

  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