Single-surface position sensor and positioning method thereof

• US 10,712,893 B2
• Filed: 02/11/2015
• Issued: 07/14/2020
• Est. Priority Date: 01/21/2015
• Status: Active Grant

• Current Assignee: Peking University
• Original Assignee: Peking University
• Inventors: Zhang, Haixia, Shi, Mayue, Chen, Haotian, Zhang, Jinxin, Han, Mengdi, Su, Zongming, Meng, Bo, Cheng, Xiaoliang
• Primary Examiner(s): Okebato, Sahlu
• Application Number:
  US15/542,599
• Publication Number:
  US 20180267650A1
• Time in Patent Office: 1,980 Days
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01D 5/20 by varying inductance, e.g. by a movable armature
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A single-surface position sensor and a positioning method thereof are disclosed. The single-surface position sensor comprises a substrate layer (1) and induction electrodes (3, 4, 5, 6); the induction electrodes (3, 4, 5, 6) are located on the substrate layer (1); the sensor further comprises a friction layer (2); the friction layer (2) is located on the substrate layer (1); the friction layer (2) is located among the induction electrodes (3, 4, 5, 6); the individual induction electrodes (3, 4, 5, 6) are grounded through the same load resistors, so that an object under test contacts with and is separated from the friction layer (2) at least one time and different voltage outputs are generated across the various load resistors; a position of the object under test is determined by analyzing a ratio of the voltages of all the electrodes (3, 4, 5, 6); the single-surface position sensor is an active sensor and reduce energy consumption as compared with traditional sensors; the single-surface position sensor can be manufactured into a flexible transparent thin film and can be widely applied to portable electronic devices and wearable devices; and the single-surface position sensor is simple in process and low in cost.

Claims

1. A single-surface position sensor, comprising:

a non-conductive substrate layer;

a non-conductive friction layer; and

induction electrodes located on the substrate layer, wherein

each of the induction electrodes are grounded through respective load resistors, each of the load resistors having the same resistance, such that when an object presses the friction layer at a contact point, an electric field generated by charges on the friction layer and on the object induces different amounts of charge at each of the induction electrodes due to different strengths of electric field on each of the respective induction electrodes according distances between the contact point and each of the respective induction electrodes, different voltage outputs are generated across load resistors corresponding to each of the induction electrodes; and

a position of the object is determined by analyzing a ratio of voltages of the respective load resistors.

2. The single-surface position sensor according to claim 1, wherein the friction layer is located on the substrate layer and between the induction electrodes.

3. The single-surface position sensor according to claim 1, wherein the friction layer is located under the substrate layer.

4. A positioning method of a single-surface position sensor adapted to the single-surface position sensor according to claim 1, comprising steps of:

dividing an operation region of the sensor in a transverse direction and a longitudinal direction into n*n sub-regions, each of the regions including a test point, and

performing induction tests on each of the test points by pressing each of the test points to obtain peak voltages of four electrodes, the peak voltages corresponding to each test point when said test point is pressed; and

calculating a transverse electrode peak voltage ratio and a longitudinal electrode peak voltage ratio corresponding to each test point according to the peak voltages of four electrodes corresponding to each test point;

fitting out a transverse fitting curve of each row of test points according to the transverse electrode peak voltage ratio of the respective electrodes corresponding to each row of test points, and fitting out a longitudinal fitting curve of each column of test points according to the longitudinal electrode peak voltage ratio of the respective electrodes corresponding to each column of test points;

connecting or fitting points corresponding to transverse electrode peak voltage ratios of a position under test on various transverse fitting curves, to obtain a curve L₁, and connecting or fitting points corresponding to longitudinal electrode peak voltage ratios of the position under test on various longitudinal fitting curves, to obtain a curve L₂; and

determining a coordinate of a point of intersection of the curve L₁ and the curve L₂ as a coordinate of the position under test.

5. The positioning method of a single-surface position sensor according to claim 4, wherein the step of fitting out the transverse fitting curve of each row of test points according to the transverse electrode peak voltage ratio of the respective electrodes corresponding to each row of test points, and fitting out the longitudinal fitting curve of each column of test points according to the longitudinal electrode peak voltage ratio of the respective electrodes corresponding to each column of test points comprises:

fitting the transverse electrode peak voltage ratio corresponding to all test points in each row of test points by a set transverse fitting formula, according to a coordinate corresponding to each test point in each row of test points, to obtain the transverse fitting curve of each row of test points; and

fitting the longitudinal electrode peak voltage ratio data corresponding to all test points in each column of test points by a set longitudinal fitting formula, according to a coordinate corresponding to each test point in each column of test points, to obtain the longitudinal fitting curve of each column of test points.

6. The positioning method of a single-surface position sensor according to claim 5, wherein the step of connecting points corresponding to transverse electrode peak voltage ratios of a position under test on various transverse fitting curves to obtain a curve L₁, and connecting points corresponding to longitudinal electrode peak voltage ratios of the position under test on various longitudinal fitting curves to obtain a curve L₂ comprises:

pressing the position under test on the single-surface position sensor to be located, to obtain peak voltages of four electrodes corresponding to the position under test, and calculating a transverse electrode peak voltage ratio and a longitudinal electrode peak voltage ratio corresponding to the position under test;

determining one designated point on each transverse fitting curve, according to the transverse electrode peak voltage ratio corresponding to the position under test, and connecting or fitting designated points on all transverse fitting curves, to obtain a possible curve L₁ of the position under test; and

determining one designated point on each longitudinal fitting curve, according to the longitudinal electrode peak voltage ratio corresponding to the position under test, and connecting or fitting designated points on all longitudinal fitting curves, to obtain a possible curve L₂ of the position under test.