Method and device for determining impedance of depression

• US 8,581,604 B2
• Filed: 09/20/2011
• Issued: 11/12/2013
• 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:
  US13/237,395
• Publication Number:
  US 20120007616A1
• Time in Patent Office: 784 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 position detection are disclosed. The device comprises a plurality of strips intersecting each other to form a plurality of intersecting regions. A pair of depressed strips intersecting on an intersecting region contact to each other on a contact point to form a depressed intersecting region, wherein the contact impedance of the contact point is determined according to the position of the depressed intersecting region and the voltages on the contact point of one and the other of the pair depressed strips.

Claims

1. A device for determining impedance of depression, comprising:

a sensor including a plurality of conductive stripes constituting a plurality of intersecting regions, 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;

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 determine a contact impedance, wherein the contact impedance of each depressed intersecting region is determined based on the potentials at the contact point of one and the other of the pair of conductive stripes or the position of the depressed intersecting region, wherein determination of 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 high and low potentials are provided to one and the other of a pair of conductive stripes, respectively; and

determining the contact impedance based on the first dimensional impedance, the second dimensional impedance, the high potential, the low potential, the first contact potential, and the second contact potential;

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.

2. The device for determining impedance of depression of claim 1, wherein the depressed intersecting region is determined by the controller based on one or both of the first contact potential and the second contact potential.

3. The device for determining impedance of depression of claim 1, wherein the determination of position of the contact point on the depressed intersecting region comprises:

sequentially selecting one and the other of the pair of the conductive stripes as a driven conductive stripe and a detected conductive stripe, respectively;

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

determining the position of the contact point based on the detected positional potentials of one and the other of the pair of the conductive stripes, respectively.

4. The device for determining impedance of depression of claim 1, wherein the determination of position of the contact point on the depressed intersecting region comprises:

sequentially selecting one and the other of each pair of the conductive stripes as a driven conductive stripe and a detected conductive stripe, respectively;

detecting the potential of the detected conductive stripe as a positional potential when providing high and low potentials 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 based on the detected positional potential of one and the other of the pair of the conductive stripes, the non-depressed and depressed potentials of the driven conductive stripe.

5. The device for determining impedance of depression of claim 1, wherein the controller further controls the driver, the detector and the selector to perform at least the following operations:

determining a depression on each depressed intersecting region; and

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

6. The device for determining impedance of depression of claim 5, wherein the controller further controls the driver, the detector and the selector to perform at least the following operations:

regarding the depression as do not exist when the total contact impedance of the depression is smaller than a threshold value; and

determining a depression location of each depression which is not yet regarded as do not exist, wherein the depression location is determined based on the contact points on all depressed intersecting regions corresponding to each depression.

7. The device for determining impedance of depression of claim 6, wherein the controller further controls the driver, the detector and the selector to perform at least the following operation:

determining the misjudgment of the depressed intersecting region by determining whether the position of the contact point is within a predetermine range of the corresponding intersecting region;

determining the misjudgment of the depression based on the misjudgment of the depressed intersecting region if the misjudgment of the depressed intersecting region is determined; and

regarding the misjudged depression as do not exist.

8. The device for determining impedance of depression of claim 5, wherein the determination of the total contact impedance is performed before the determination of the position of the contact point.