Method and device for position detection

• US 8,633,716 B2
• Filed: 09/20/2011
• 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:
  US13/236,905
• Publication Number:
  US 20120007609A1
• Time in Patent Office: 854 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 to form a depressed intersecting region. According to the depressed intersecting regions, each depression can be determined. The total contact impedance of a depressing crossover a plurality of intersecting regions is the parallel contact impedance of the contact impedances of all intersecting regions corresponding to the same depression.

Claims

1. A method for position detection, 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 on the intersecting regions;

determining a contact impedance of each intersecting region corresponding to each depression that crosses intersecting regions; and

determining a total contact impedance for each depression that crosses intersecting regions, wherein the total contact impedance is the parallel impedance of contact impedances of all intersecting regions corresponding to the same depression, and the total contact impedance for the depression decreases when the area of the depression increases, wherein the area of depression is the area of electrical contact between conductive stripes correspondent to the same depression.

2. The method for position detection of claim 1, further comprising the following operation of tracing subsequent depressions of each depression based on the total contact impedance of each depression, wherein the differences of total contact impedances of each depression and its each subsequent depression is within a predetermine range, and the depressed intersecting regions corresponding to the same depression are neighboring intersecting regions.

3. The method for position detection of claim 1, wherein the contact impedance is determined based on the potential difference between one and the other of the pair of conductive stripes at the contact point and the position of the contact point.

4. The method for position detection of claim 1, wherein 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 high and low potentials 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 of claim 1, wherein the contact impedance is determined based on the potential difference of one and the other of the pair of conductive stripes at the contact point and the position of the depressed intersecting region.

6. The method for position detection of claim 5, wherein 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 high and low potentials are provided to 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.

7. The method for position detection of claim 1, further comprising:

determining depressions to be eliminated among the depressions, wherein depressions to be eliminated will need to meet at least one of the following conditions;

the total contact impedance is smaller than a threshold value; and

the position of at least one contact point in all contact points corresponding to the same depression falls outside a tolerance range of a corresponding intersecting region; and

determining every non-eliminated depression positions among all the depressions, wherein the position of each depression is determined based on the position of the contact point of the depressed intersecting region corresponding to the same depression.

8. The method for position detection of claim 1, wherein the determination of the contact points of the depressed intersecting regions 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;

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

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 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 depressed potential when the extension conductive stripe is depressed; 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.

9. The method for position detection of claim 1, further comprising:

directly or indirectly via an extension resistor providing high and low potentials to a first end and a second end of the same conductive stripe, respectively;

directly or indirectly providing high and low potentials to the first end of at least one first conductive stripe and the first end of at least one second conductive stripe, respectively;

detecting a signal between one of the conductive stripes and the extension resistor;

detecting the potential at the first end, the second end or both ends of the other of the pair of conductive stripes when one of a pair of conductive stripes is provided with high and low potentials; and

detecting the potentials at the second ends of one of the first conductive stripes and one of the second conductive stripes, respectively.

10. The method for position detection of claim 1, further comprising the following operation of detecting the signal between the conductive stripe and the extension resistor when high and low potentials are respectively provided to a first and a second ends of the same conductive stripe via the extension resistor.