Strain gauge having unbalanced bias for single sided applications

Patent metadata

Field	Value
Publication number	US-11415405-B2
Application number	US-202016858110-A
Country	US
Kind code	B2
Filing date	Apr 24, 2020
Priority date	Apr 24, 2020
Publication date	Aug 16, 2022
Grant date	Aug 16, 2022

Abstract

Disclosed herein is a strain gauge including a substrate, with a first Wheatstone bridge arrangement of resistors disposed on a first surface of the substrate, and a second Wheatstone bridge arrangement of resistors disposed remotely from the first Wheatstone bridge arrangement of resistors. The resistors of the first Wheatstone bridge arrangement are equal in resistance to one another, while the resistors of the second Wheatstone bridge arrangement are unequal in resistance to one another and unequal to those of the first Wheatstone bridge arrangement. The first Wheatstone bridge arrangement of resistors are electrically connected in parallel with the second Wheatstone bridge arrangement of resistors such that each resistor of the first Wheatstone bridge arrangement is electrically connected in parallel with a different resistor of the second Wheatstone bridge arrangement.

First claim

The invention claimed is:

1. A strain gauge, comprising:
a substrate;
a first Wheatstone bridge arrangement of resistors disposed on a first surface of the substrate, the resistors of the first Wheatstone bridge arrangement being equal in resistance;
wherein the first Wheatstone bridge arrangement of resistors comprises:
a first resistor coupled between a first node and a fourth node;
a second resistor coupled between the first node and a second node;
a third resistor coupled between a third node and the fourth node; and
a fourth resistor coupled between the second node and the third node; and

a second Wheatstone bridge arrangement of resistors, some of the resistors of the second Wheatstone bridge arrangement being unequal in resistance to one another, and being unequal in resistance to the resistors of the first Wheatstone bridge arrangement of resistors;
wherein the second Wheatstone bridge arrangement of resistors comprises:
a fifth resistor coupled between the first node and the fourth node;
a sixth resistor coupled between the first node and the second node;
a seventh resistor coupled between the third node and the fourth node; and
an eighth resistor coupled between the second node and the third node;

wherein the first Wheatstone bridge arrangement of resistors are electrically connected in parallel with the second Wheatstone bridge arrangement of resistors such that each resistor of the first Wheatstone bridge arrangement is electrically connected in parallel with a different resistor of the second Wheatstone bridge arrangement.

2. The strain gauge of claim 1 , wherein the resistors of the first and second Wheatstone bridge arrangements are physically arranged successively next to one another along a longitudinal axis of the substrate.

3. The strain gauge of claim 1 , wherein an output of the strain gauge is a voltage differential between potentials at the second node and the fourth node.

4. The strain gauge of claim 1 , wherein the first node is connected to a supply voltage and the third node is connected to ground.

5. The strain gauge of claim 1 , wherein the second Wheatstone bridge arrangement of resistors is remotely located from the first Wheatstone bridge arrangement of resistors.

6. The strain gauge of claim 1 , wherein the second Wheatstone bridge arrangement off resistors is not disposed on or in the substrate.

7. A method of measuring strain on a substrate due to force applied to the substrate, the method comprising:
applying a supply voltage and a ground voltage across a pair of parallel connected Wheatstone bridge resistor arrangements, a first of the pair of Wheatstone bridge resistor arrangements being disposed on a first surface of the substrate and comprising a first resistor coupled between a first node and a fourth node, a second resistor coupled between the first node and a second node, a third resistor coupled between a third node and the fourth node, and a fourth resistor coupled between the second node and the third node;
applying the force to the substrate; and
measuring a differential voltage across output nodes of the pair of parallel connected Wheatstone bridge resistor arrangements present because the resistors of the first of the pair of Wheatstone bridge resistor arrangements are equal in resistance while some of the resistors of a second of the pair of Wheatstone bridge resistor arrangements are unequal in resistance, the second of the pair of Wheatstone bridge arrangements comprising a fifth resistor coupled between the first node and the fourth node, a sixth resistor coupled between the first node and the second node, a seventh resistor coupled between the third node and the fourth node, and an eighth resistor coupled between the second node and the third node.

8. The method of claim 7 , further comprising, prior to application of the supply voltage and the ground voltage across the pair of parallel connected Wheatstone bridge resistor arrangements, physically arranging the resistors of the first Wheatstone bridge resistor arrangement successively next to one another along a longitudinal axis of the substrate.

9. An electronic device, comprising:
a substrate;
a first Wheatstone bridge arrangement of resistors disposed on a first surface of the substrate, the resistors of the first Wheatstone bridge arrangement being equal in resistance;
wherein the first Wheatstone bridge arrangement of resistors comprises:
a first resistor coupled between a first node and a fourth node;
a second resistor coupled between the first node and a second node;
a third resistor coupled between a third node and the fourth node; and
a fourth resistor coupled between the second node and the third node; and

a second Wheatstone bridge arrangement of resistors disposed on a component remotely located from the substrate, some of the resistors of the second Wheatstone bridge arrangement being unequal in resistance to one another, and being unequal in resistance to the resistors of the first Wheatstone bridge arrangement of resistors;
wherein the second Wheatstone bridge arrangement of resistors comprises:
a fifth resistor coupled between the first node and the fourth node;
a sixth resistor coupled between the first node and the second node;
a seventh resistor coupled between the third node and the fourth node; and
an eighth resistor coupled between the second node and the third node;

wherein the first Wheatstone bridge arrangement of resistors are electrically connected in parallel with the second Wheatstone bridge arrangement of resistors such that each resistor of the first Wheatstone bridge arrangement is electrically connected in parallel with a different resistor of the second Wheatstone bridge arrangement.

10. The electronic device of claim 9 , wherein the component comprises an electronic board.

11. The electronic device of claim 9 , wherein the component comprises a layer within a touch screen.

12. The electronic of claim 9 , wherein the resistors of the first and second Wheatstone bridge arrangements are physically arranged successively next to one another along a longitudinal axis of the substrate.

13. The electronic device of claim 9 , wherein an output of the electronic device is a voltage differential between potentials at the second node and the fourth node.

14. The electronic device of claim 9 , wherein the first node is connected to a supply voltage and the third node is connected to ground.

Assignees

• St Microelectronics Asia Pacific Pte Ltd
• STMicroelectronics Asia Pacific Ptd Ltd

Inventors

• Hong Sa Hyang
• Kang Jun Hwan
• On Yun Sang

Classifications

• G01B7/18 Primary

  using change in resistance · CPC title

• G06F2203/04105

  Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position · CPC title

• G06F3/04144

  using an array of force sensing means (position sensing using the local deformation of sensor cells G06F3/0447) · CPC title

• G01L1/044

  of leaf springs · CPC title

• G01L1/225

  Measuring circuits therefor · CPC title