Pressure sensing element (and safety apparatus) having intermediate layer with two functional layers

Patent metadata

Field	Value
Publication number	US-11029220-B2
Application number	US-201515757526-A
Country	US
Kind code	B2
Filing date	Dec 21, 2015
Priority date	Sep 3, 2015
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A pressure sensing element may include: an intermediate layer having a structure in which at least two functional layers are stacked on each other; a first electrode layer including a plurality of first electrode patterns; and a second electrode layer to overlap the first electrode layer with the intermediate layer between the first and second electrode layers. Among the two functional layers, the first functional layer has a thickness linearly varying in a first pressure section, and the second functional layer has a thickness linearly varying in a second pressure section. The maximum pressure in the first pressure section is lower than that in the second pressure section, and the minimum pressure in the second pressure section is included in the first pressure section.

First claim

The invention claimed is:

1. A pressure sensing element comprising:
an intermediate layer having a structure in which at least two functional layers are stacked, wherein the at least two functional layers includes a first functional layer and a second functional layer;
a first electrode layer disposed on one surface of the intermediate layer and including a plurality of first electrode patterns; and
a second electrode layer disposed on an opposing surface of the intermediate layer to overlap the first electrode layer with the intermediate layer between the first electrode layer and the second electrode layer, the first functional layer is to face the plurality of first electrode patterns, and the second functional layer is to face the second electrode layer such that the second functional layer is between the first functional layer and the second electrode layer,
wherein a thickness of the first functional layer varies based on pressure applied to the pressure sensing element, the thickness of the first functional layer is to linearly vary within a first strain percentage range of the first functional layer when the applied pressure is within a first pressure range, and the thickness of the first functional layer is to vary at a different rate within a second strain percentage range of the first functional layer when the applied pressure is equal to or greater than pressure in the first pressure range, wherein the first pressure range is a pressure amount that ranges from a first pressure to a second pressure, the first strain percentage range of the first functional layer is a strain percentage that ranges from a first strain percentage to a second strain percentage, and
a thickness of the second functional layer varies based on pressure applied to the pressure sensing element, the thickness of the second functional layer is to linearly vary within a second strain percentage range of the second functional layer when the applied pressure is within a second pressure range, the thickness of the second functional layer is to vary at a different rate within a first strain percentage range of the second functional layer when the applied pressure is equal to or less than pressure in the second pressure range, and the thickness of the second functional layer is to vary at a different rate within a third strain percentage range of the second functional layer when the applied pressure is equal to or greater than pressure within the second pressure range, wherein the second pressure range is a pressure amount that ranges from a third pressure to a fourth pressure, the first strain percentage range of the second functional layer is a strain percentage that ranges from a third strain percentage to a fourth strain percentage, the second strain percentage range of the second functional layer is a strain percentage that ranges from the fourth strain percentage to a fifth strain percentage, and the third strain percentage range of the second functional layer is a strain percentage that is equal to or great than the fifth strain percentage, wherein the fifth strain percentage is greater than the fourth strain percentage, and
a maximum tolerable pressure that the first functional layer can withstand within the first pressure range is equivalent to a minimum amount of pressure within the second pressure range, wherein the maximum tolerable pressure within the first pressure range is the second pressure, and the minimum amount of pressure within the second pressure range is the third pressure,
wherein the first strain percentage range of the first functional layer is greater than the second strain percentage range of the first functional layer, and
wherein the second strain percentage range of the second functional layer is greater than the first strain percentage range of the second functional layer.

2. The pressure sensing element of claim 1 , wherein a thickness of the intermediate layer is to linearly vary when the applied pressure is within a third pressure range, the third pressure range is a pressure amount including a range from a minimum amount of pressure within the first pressure range to a maximum tolerable pressure that the second functional layer can withstand within the second pressure range.

3. The pressure sensing element of claim 1 , wherein the intermediate layer has a structure in which the first functional layer is disposed on the second functional layer.

4. The pressure sensing element of claim 3 , wherein CFD first functional layer 25%, which is a pressure at which the thickness of the first functional layer is reduced by 25%, and CFD second functional layer 25%, which is a pressure at which the thickness of the second functional layer is reduced by 25%, satisfy the following Expression 1:
1<CFD second functional layer 25%/CFD first functional layer 25%≤20,  Expression 1

(Compression Force Deflection; CFD).

5. The pressure sensing element of claim 3 , wherein, when a third functional layer is further disposed below the second functional layer such that the third functional layer is between the second functional layer and the second electrode layer, a thickness of the third functional layer is to linearly vary when the applied pressure is within a fourth pressure range, a maximum tolerance pressure within the fourth pressure range is higher than a maximum tolerance pressure within the second pressure range, and a minimum amount of pressure within the fourth pressure range is within a range of pressures within the second pressure range.

6. The pressure sensing element of claim 5 , wherein a thickness of the intermediate layer is to linearly vary when the applied pressure is within a third pressure range, the third pressure range is a pressure amount that includes a range from a minimum amount of pressure within the first pressure range to the maximum tolerance pressure within the fourth pressure range.

7. The pressure sensing element of claim 5 , wherein CFD first functional layer 25%, which is a pressure at which the thickness of the first functional layer is reduced by 25%, and CFD third functional layer 25%, which is a pressure at which the thickness of the third functional layer is reduced by 25%, satisfy the following Expression 2:
1<CFD third functional layer 25%/CFD first functional layer 25%≤20  Expression 2

8. The pressure sensing element of claim 1 , further comprising an adhesion layer disposed between the first functional layer and the second functional layer.

9. The pressure sensing element of claim 1 , wherein the first and second functional layers include a conductive filler.

10. The pressure sensing element of claim 1 , wherein the first electrode patterns are arranged in a first direction, and the second electrode layer includes a plurality of second electrode patterns arranged in the first direction.

11. The pressure sensing element of claim 1 , wherein:
the first electrode patterns are arranged in a first direction; and
the second electrode pattern includes a plurality of second electrode patterns arranged in a second direction crossing the first direction.

12. An apparatus comprising:
a pressure sensing element including an intermediate layer having a structure in which at least two functional layers are stacked, a first electrode layer disposed on one surface of the intermediate layer and including a plurality of first electrode patterns, and a second electrode layer disposed on an opposing surface of the intermediate layer to overlap the first electrode layer with the intermediate layer between the first electrode layer and the second electrode layer, the at least two functional layers including a first functional layer and a second functional layer,

Assignees

• Lg Innotek Co Ltd

Inventors

• Kim Bi Yi
• Kim Jeong Han
• Park Hyun Gyu
• Cho Won Keun
• Cho In Hee
• Jo Hyun Jin
• Hong Seung Kwon

Classifications

• G01L1/142 Primary

  using capacitors · CPC title

• G01L1/2287

  constructional details of the strain gauges (adjustable resistors H01C10/00) · CPC title

• G01L1/18

  using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material · CPC title

• G01L1/14 Primary

  by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators · CPC title

• G01L5/22

  for measuring the force applied to control members, e.g. control members of vehicles, triggers · CPC title