Method and device for position detection with palm rejection

• US 8,633,718 B2
• Filed: 09/21/2011
• Issued: 01/21/2014
• Est. Priority Date: 04/17/2009
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: Yeh, Shang-Tai, Chen, Jia-Ming, Ho, Shun-Lung
• Primary Examiner(s): PATEL, PARESH H
• Application Number:
  US13/238,439
• Publication Number:
  US 20120007618A1
• Time in Patent Office: 853 Days
• Field of Search: None
• US Class Current: 324/691
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• 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 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A method and the device for palm ignoring disclosed. The device comprises a plurality of strips intersecting each other to form a plurality of intersecting regions. A pair of strips intersecting on an intersecting region contact to each other on a contact point to form a depressed intersecting region. The depression depressed by the palm can be determined by comparing the total impedance of the depression with a threshold so as to be ignored.

Claims

1. A method for position detection with palm rejection, comprising:

providing a plurality of intersecting regions constituted by a plurality of intersecting conductive stripes, wherein a pair of depressed conductive stripes intersected in an intersecting region form a contact point due to electrical contact so as to define a depressed intersecting region;

determining a contact impedance of each intersecting region;

determining each depression based on the intersecting regions;

determining a total contact impedance for each depression, wherein the total compact impedance is the parallel impedance of contact impedances of all intersecting regions corresponding to the same depression;

distinguishing the depression made by a pen or a palm based on the total contact impedance of each depression;

determining each depression position of the pen; and

outputting each depression position that is not made by the palm.

2. The method for position detection with palm rejection of claim 1, wherein each depression is determined a palm depression by determining whether the total contact impedance is smaller than a threshold value.

3. The method for position detection with palm rejection of claim 1, wherein the contact impedance is determined by the potentials of one and the other of the pair of conductive stripes at the contact point and the position of the depressed intersecting region, and the determination of the contact impedance comprises:

determining a first dimensional impedance and a second dimensional impedance based on the position of the depressed intersecting region;

detecting a first contact potential and a second contact potential of one and the other of the pair of conductive stripes at the contact point when a high potential and a low potential are provided to one and the other of a pair of conductive stripes, respectively; and

determining the contact impedance, wherein the contact impedance is (R1+R2)/(((VH−

VL)/(P1−

P2))−

1), wherein R1, R2, VH, VL, P1, and P2 are the first dimensional impedance, the second dimensional impedance, the high potential, the low potential, the first contact potential, and the second contact potential, respectively.

4. The method for position detection with palm rejection of claim 1, wherein the contact impedance is determined by the potentials of one and the other of the pair of conductive stripes at the contact point and the position of the contact point, and the determination of the contact impedance comprises:

determining a first dimensional location and a second dimensional location of the contact point, and determining a first dimensional impedance and a second dimensional impedance based on the first dimensional location and the second dimensional location;

detecting a first contact potential and a second contact potential of one and the other of the pair of conductive stripes at the contact point when a high potential and a low potential are provided to one and the other of a pair of conductive stripes, respectively; and

determining the contact impedance, wherein the contact impedance is (R1+R2)/(((VH−

VL)/(P1−

P2))−

1), wherein R1, R2, VH, VL, P1, and P2 are the first dimensional impedance, the second dimensional impedance, the high potential, the low potential, the first contact potential, and the second contact potential, respectively.

5. The method for position detection with palm rejection of claim 1, wherein the determination of the position of the contact point comprises:

selecting one and the other of the pair of the conductive stripes at the contact point as a driven conductive stripe and a detected conductive stripe, respectively, wherein the driven conductive stripe is conductive stripe that crosses the conductive stripes on the same layer;

detecting the potential of the detected conductive stripe as a positional potential when providing a high potential and a low potential to both ends of the driven conductive stripe;

electrically coupling an extension resistor and the driven conductive stripe to form an extension conductive stripe;

when the extension conductive stripe is not depressed, providing high and low potentials to the extension conductive stripe to detect the potential between the extension resistor and the driven conductive stripe as a non-depressed potential;

when the extension conductive stripe is depressed, providing high and low potentials to the extension conductive stripe to detect the potential between the extension resistor and the driven conductive stripe as a depressed potential; and

determining the position of the contact point on the driven conductive stripe based on the positional potential, the non-depressed and depressed potentials of the driven conductive stripe.

6. A method for correcting position error by palm rejection, comprising:

providing a plurality of intersecting regions constituted by a plurality of intersecting conductive stripes, wherein a pair of conductive stripes intersected in an intersecting region form a contact point due to electrical contact so as to define a depressed intersecting region;

determining each depression based on the intersecting regions;

determining each depression whether a palm depression;

determining each position of the contact points that are not made by the palm;

correcting the depression position that is not made by the palm when a contact impedance across conductive stripes on the same layer is existed on the conductive stripe with any contact point;

determining each depression position that is not made by the palm based on each position of the contact points that are not made by the palm; and

outputting each depression position that is not made by the palm.

7. The method for correcting position error by palm rejection of claim 6, wherein the determination that each depression is determined whether a palm depression comprises:

determining a contact impedance of each depressed intersecting region;

determining a total contact impedance based on the contact impedance of the depressed intersecting region corresponding to each depression, wherein the total compact impedance for a depression that crosses intersecting regions is the parallel impedance of contact impedances of all intersecting regions; and

determining whether each depression is a palm depression by determining whether the total contact impedance is smaller than a threshold value.

8. The method for correcting position error by palm rejection of claim 7, further comprising the step of determining each intersecting region whether a depressed intersecting region, wherein the determination comprises:

detecting the contact potentials of one and the other of the pair of conductive stripes; and

determining the intersecting region whether the depressed intersecting region based on at least one of the contact potentials, wherein the contact potentials are the potentials of one and the other of the pair of depressed conductive stripes at the contact point when the depressed intersecting region is determined.

9. The method for correcting position error by palm rejection of claim 8, wherein the contact impedance is determined based on the potentials of one and the other of the pair of conductive stripes at the contact point and the position of the depressed intersecting region, and the determination of the contact impedance comprises:

determining a first dimensional impedance and a second dimensional impedance based on the position of the depressed intersecting region;

letting the potentials of one and the other of the pair of conductive stripes at the contact point as a first contact potential and a second contact potential, respectively, wherein the first contact potential and the second contact potential are determined when a high potential and a low potential are provided to both ends of one and the other of the pair of conductive stripes, respectively; and

determining the contact impedance, wherein the contact impedance is (R1+R2)/(((VH−

VL)/(P1−

P2))−

1), wherein R1, R2, VH, VL, P1, and P2 are the first dimensional impedance, the second dimensional impedance, the high potential, the low potential, the first contact potential, and the second contact potential, respectively.

10. The method for correcting position error by palm rejection of claim 8, wherein the contact impedance is determined by the potentials of one and the other of the pair of conductive stripes at the contact point and the position of the contact point, and the determination of the contact impedance comprises:

determining a first dimensional location and a second dimensional location of the contact point, and determining a first dimensional impedance and a second dimensional impedance based on the first dimensional location and the second dimensional location;

detecting a first contact potential and a second contact potential of one and the other of the pair of conductive stripes at the contact point when a high potential and a low potential are provided to one and the other of a pair of conductive stripes, respectively; and

determining the contact impedance, wherein the contact impedance is (R1+R2)/(((VH−

VL)/(P1−

P2))−

1), wherein R1, R2, VH, VL, P1, and P2 are the first dimensional impedance, the second dimensional impedance, the high potential, the low potential, the first contact potential, and the second contact potential, respectively.

11. The method for correcting position error by palm rejection of claim 8, wherein the correction of the depression position that is not made by the palm comprises:

correcting the position of each contact point of the depression that is not made by the palm, wherein the depression is on the conductive stripe with the contact impedance across conductive stripes on the same layer; and

determining the depression position that is not made by the palm based on the positions of all contact points corresponding to the depression that is not made by the palm.

12. The method for correcting position error by palm rejection of claim 11, wherein the correction of the position of the contact point comprises:

selecting one and the other of the pair of the conductive stripes at the contact point as a driven conductive stripe and a detected conductive stripe, respectively, wherein the driven conductive stripe is the conductive stripe across the conductive stripes on the same layer;

detecting the potential of the detected conductive stripe as a positional potential when providing a high potential and a low potential to both ends of the driven conductive stripe;

electrically coupling an extension resistor and the driven conductive stripe to form an extension conductive stripe;

when the extension conductive stripe is not depressed, providing high and low potentials to the extension conductive stripe to detect the potential between the extension resistor and the driven conductive stripe as a non-depressed potential;

when the extension conductive stripe is depressed, providing high and low potentials to the extension conductive stripe to detect the potential between the extension resistor and the driven conductive stripe as a depressed potential; and

determining the position of the contact point on the driven conductive stripe based on the positional potential, the non-depressed and depressed potentials of the driven conductive stripe.

13. A device for correcting position error by palm rejection, comprising:

a sensor including a plurality of conductive stripes constituting a plurality of intersecting regions, wherein a pair of depressed conductive stripes intersected in a intersecting region form a contact point due to electrical contact so as to define a depressed intersecting region;

a driver for providing a high potential and a low potential;

a detector for detecting a signal of at least one conductive stripe;

a selector for operatively coupling the conductive stripes with the driver and the detector; and

a controller for controlling the driver, the detector and the selector to perform at least the following operations;

determining each depression based on the intersecting regions;

determining each depression whether a depression is made by a palm;

determining the position of each contact point of the depression that is not made by the palm;

correcting the depression position that is not made by the palm when a contact impedance across conductive stripes on the same layer is existed on the conductive stripe with any contact point;

determining each depression position that is not made by the palm based on each position of the contact points that are not made by the palm; and

outputting each depression position that is not made by the palm.

14. The device for correcting position error by palm rejection of claim 13, wherein the determination that each depression is determined whether a palm depression comprises:

determining a contact impedance of each depressed intersecting region;

determining a total contact impedance based on the contact impedance of the depressed intersecting region corresponding to each depression, wherein the total compact impedance for a depression that crosses intersecting regions is the parallel impedance of contact impedances of all intersecting regions; and

determining whether each depression is a palm depression by determining whether the total contact impedance is smaller than a threshold value.

15. The device for correcting position error by palm rejection of claim 14, wherein the controller further controls the driver, the detector and the selector to perform the following operation of determining each intersecting region whether the depressed intersecting region, and the operation comprises:

detecting the contact potentials of one and the other of the pair of conductive stripes; and

determining the intersecting region whether the depressed intersecting region based on at least one of the contact potentials, wherein the contact potentials are the potentials of one and the other of the pair of depressed conductive stripes at the contact point when the depressed intersecting region is determined.

16. The device for correcting position error by palm rejection of claim 15, wherein the contact impedance is determined by the potentials of one and the other of the pair of conductive stripes at the contact point and the position of the depressed intersecting region, and the determination of the contact impedance comprises:

determining a first dimensional impedance and a second dimensional impedance based on the position of the depressed intersecting region;

letting the potentials of one and the other of the pair of conductive stripes at the contact point as a first contact potential and a second contact potential, respectively, wherein the first contact potential and the second contact potential are determined when a high potential and a low potential are provided to both ends of one and the other of the pair of conductive stripes, respectively; and

determining the contact impedance, wherein the contact impedance is (R1+R2)/(((VH−

VL)/(P1−

P2))−

1), wherein R1, R2, VH, VL, P1, and P2 are the first dimensional impedance, the second dimensional impedance, the high potential, the low potential, the first contact potential, and the second contact potential, respectively.

17. The device for correcting position error by palm rejection of claim 15, wherein the contact impedance is determined by the potentials of one and the other of the pair of conductive stripes at the contact point and the position of the contact point, and the determination of the contact impedance comprises:

determining a first dimensional location and a second dimensional location of the contact point, and determining a first dimensional impedance and a second dimensional impedance based on the first dimensional location and the second dimensional location;

detecting a first contact potential and a second contact potential of one and the other of the pair of conductive stripes at the contact point when a high potential and a low potential are provided to one and the other of a pair of conductive stripes, respectively; and

determining the contact impedance, wherein the contact impedance is (R1+R2)/(((VH−

VL)/(P1−

P2))−

1), wherein R1, R2, VH, VL, P1, and P2 are the first dimensional impedance, the second dimensional impedance, the high potential, the low potential, the first contact potential, and the second contact potential, respectively.

18. The device for correcting position error by palm rejection of claim 13, wherein the correction of the depression position that is not made by the palm comprises:

correcting the position of each contact point of the depression that is not made by the palm, wherein the depression is on the conductive stripe with the contact impedance across conductive stripes on the same layer; and

determining the depression position that is not made by the palm based on the positions of all contact points corresponding to the depression that is not made by the palm.

19. The device for correcting position error by palm rejection of claim 18, wherein the correction of the position of the contact point comprises:

determining the position of the contact point on each depressed intersecting region, wherein the determination of the position of each contact point comprises;

selecting one and the other of the pair of the conductive stripes at the contact point as a driven conductive stripe and a detected conductive stripe, respectively, wherein the driven conductive stripe is the conductive stripe across the conductive stripes on the same layer;

detecting the potential of the detected conductive stripe as a positional potential when providing a high potential and a low potential to both ends of the driven conductive stripe;

electrically coupling an extension resistor and the driven conductive stripe to form an extension conductive stripe;

when the extension conductive stripe is not depressed, providing high and low potentials to the extension conductive stripe to detect the potential between the extension resistor and the driven conductive stripe as a non-depressed potential;

when the extension conductive stripe is depressed, providing high and low potentials to the extension conductive stripe to detect the potential between the extension resistor and the driven conductive stripe as a depressed potential; and

determining the position of the contact point on the driven conductive stripe based on the positional potential, the non-depressed and depressed potentials of the driven conductive stripe.