Method and device for dual-differential sensing

• US 9,798,427 B2
• Filed: 10/15/2014
• Issued: 10/24/2017
• 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
• Primary Examiner(s): Sitta, Grant
• Application Number:
  US14/514,797
• Publication Number:
  US 20150029127A1
• Time in Patent Office: 1,105 Days
• Field of Search: 345100, 345173-175
• 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 dual-differential sensing is disclosed. The sensing information can be generated from signals provided by a sensing device with a plurality of sensors. Each value of the sensing information corresponds to signals of three sensors, respectively. The sensing device is flexible and configured on a display. The noise effect of the display on the signal of each sensor corresponds to the distance between the display and the sensor. Besides, the noise effect of the display on each value of the sensing information corresponds to the distances between the display and the three sensors, respectively.

Claims

1. A sensing method for a touch sensitive panel, wherein said touch sensitive panel including a plurality of sensors which are sequentially parallel conductive lines across said touch sensitive panel, the sensing method comprising:

receiving values in one scan of said plurality of sensors, respectively;

calculating difference values corresponding to each of said sensors having two neighboring parallel sensors, wherein each of said difference value is calculated by subtracting twice of a second value corresponding to a second sensor among the plurality of sensors from a sum of a first value corresponding to a first sensor next to the second sensor and a third value corresponding to a third sensor next to the second sensor or subtracting the sum of said first value and said third value from twice of said second value; and

obtaining a sensing result based on differential sensing information, and determining each location on said touch sensitive panel touched or approached by at least one external object according to said sensing result, wherein said differential sensing information comprises said difference values.

2. The sensing method of claim 1, wherein said touch sensitive panel is on top of a display, at least two of the following distances are different:

a first distance between said first sensor and said display;

a second distance between said second sensor and said display;

a third distance between said third sensor and said display.

3. The sensing method of claim 2, wherein said second distance is larger than said first distance and said third distance is larger than said second distance.

4. The sensing method of claim 1, wherein said step of subtracting twice of said second value from a sum of said first value and said third value is further performed by one of the calculating steps:

first calculating steps, comprising;

subtracting said second value from said first value for generating a first difference;

subtracting said third value from said second value for generating a second difference; and

subtracting said second difference from said first difference; and

second calculating steps, comprising;

subtracting said second value from said first value for generating a third difference;

subtracting said second value from said third value for generating a fourth difference; and

adding said third difference and said fourth difference.

5. The sensing method of claim 1, wherein said step of subtracting the sum of said first value and said third value from twice of said second value is performed by one of the calculating steps:

first calculating steps, comprising;

subtracting said first value from said second value for generating a first difference;

subtracting said second value from said third value for generating a second difference; and

subtracting said second difference from said first difference; and

second calculating steps, comprising;

subtracting said first value from said second value for generating a third difference;

subtracting said third value from said second value for generating a fourth difference; and

adding said third difference and said fourth difference.

6. The sensing method of claim 1, wherein said sensing result has two zero-crossings related to each location touched or approached by said at least one external object.

7. The sensing method of claim 1, wherein said sensing result falls within a zero-value range with respect to locations not touched or approached by said at least one external object.

8. A sensing apparatus for a touch sensitive panel, wherein said touch sensitive panel including a plurality of sensors which are sequentially parallel conductive lines across said touch sensitive panel, the sensing apparatus comprising:

a sensing module, configured to scan said plurality of sensors for generating values, respectively;

a calculating module, configured to calculate difference values corresponding to each of said sensors having two neighboring parallel sensors, wherein each of said difference value is calculated by subtracting twice of a second value corresponding to a second sensor among the plurality of sensors from a sum of a first value corresponding to a first sensor next to the second sensor and a third value corresponding to a third sensor next to the second sensor or subtracting the sum of said first value and said third value from twice of said second value; and

a controller, configured to obtain a sensing result based on differential sensing information, and to determine each location on said touch sensitive panel touched or approached by at least one external object according to said sensing result, wherein said differential sensing information comprises said difference values.

9. The sensing apparatus of claim 8, wherein said touch sensitive panel is on top of a display, at least two of the following distances are different:

a first distance between said first sensor and said display;

a second distance between said second sensor and said display;

a third distance between said third sensor and said display.

10. The sensing apparatus of claim 9, wherein said second distance is larger than said first distance and said third distance is larger than said second distance.

11. The sensing apparatus of claim 8, wherein said calculating module for subtracting twice of said second value from a sum of said first value and said third value further comprises one of the calculating modules:

a first calculating module, comprising;

a first first-stage subtractor for subtracting said second value from said first value to generate a first difference;

a second first stage subtractor for subtracting said third value from said second value to generate a second difference; and

a second-stage subtractor for subtracting said second difference from said first difference; and

a second calculating module, comprising;

a third first-stage subtractor for subtracting said second value from said first value to generate a third difference;

a fourth first-stage subtractor for subtracting said second value from said third value to generate a fourth difference; and

a second-stage adder for adding said third difference and said fourth difference.

12. The sensing apparatus of claim 8, wherein said calculating module for subtracting the sum of said first value and said third value from twice of said second value further comprises one of the calculating modules:

a first calculating module, comprising;

a first first-stage subtractor for subtracting said first value from said second value to generate a first difference;

a second first-stage subtractor for subtracting said second value from said third value to generate a second difference; and

a second-stage subtractor for subtracting said second difference from said first difference; and

a second calculating module, comprising

a third first-stage subtractor for subtracting said first value from said second value to generate a third difference;

a fourth first-stage subtractor for subtracting said third value from said second value to generate a fourth difference; and

a second-stage adder for adding said third difference and said fourth difference.

13. The sensing apparatus of claim 8, wherein said sensing result has two zero-crossings related to each location touched or approached by said at least one external object.

14. The sensing apparatus of claim 8, wherein said sensing result falls within a zero-value range with respect to locations not touched or approached by said at least one external object.

15. The sensing apparatus of claim 8, wherein said first value, said second value, and said third value are generated in one scan of said first sensor, said second sensor, and said third sensor.