Unlock instant, AI-driven research and patent intelligence for your innovation.

Flexible strained sensor with protective coating

a sensor and flexible technology, applied in the field of strain sensors, can solve the problems of metal or semiconductors having limitations when applied to strain sensors, abnormal resistance variations of cnts (serving as resistors), and reducing durability (or machine life) in sensing functionality, so as to prevent unwanted resistance variation of cnt films, prevent excessive thickness of cnt films, and prevent a reduction of resistance

Active Publication Date: 2015-11-10
YAMAHA CORP +1
View PDF49 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0013]It is an object of the present invention to provide a strain sensor which is able to prevent the occurrence of damage / breakage of CNT films and / or inclusion of foreign matters into CNTs, and which is able to improve durability in sensing functionality.

Problems solved by technology

However, metals or semiconductors have limitations when applied to strain sensors because they may produce a small amount of strain due to reversible expansion and contraction.
This may cause abnormality in resistance variations of CNTs (serving as resistors), for example, when CNT films are unexpectedly damaged or broken due to abrupt contact with materials, when foreign matters unexpectedly enter into gaps formed between CNTs, and / or when moisture or floating gas is applied to CNTs.
This may degrade durability (or machine life) in sensing functionality.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

first embodiment

1. First Embodiment

[0033]A strain sensor 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1A and 1B. FIG. 1A is a cross-sectional view of the strain sensor 1, while FIG. 1B is a plan view of the strain sensor 1. The strain sensor 1 includes a substrate 2, a CNT film 4, a pair of electrodes 3, and a protective coat 5. The CNT film 4 made of a plurality of CNT fibers 8 oriented in one direction are formed on the surface of the substrate 2. The electrodes 3 are formed on opposite ends of the substrate 2 lying in a direction A which differs from the orientation direction of the CNT fibers 8. The protective coat 5 is formed to protect the CNT film 4.

[0034]The substrate 2 is a plate-like substance having flexibility. The substrate 2 is not necessarily limited in size and dimensions. For example, the thickness of the substrate 2 may range from 10 μm to 5 mm; the width thereof may range from 1 mm to 5 cm; and the length thereof may range f...

second embodiment

3. Second Embodiment

[0072]FIGS. 4A and 4B show a strain sensor 21 according to a second embodiment of the present invention, wherein parts identical to those of the strain sensor 1 shown in FIGS. 1A and 1B are designated using the same reference signs. The strain sensor 21 includes a pair of electrodes 13, a CNT film 14, a protective coat 15, and a resin layer 16 on the substrate 2.

[0073]The CNT film 14 is directly laminated on the surface of the substrate 2. The CNT film 14 includes a plurality of CNT fibers 8 which adjoin each other with gaps therebetween. The protective coat 15 is permeated into at least part of the gaps formed between the CNT fibers 8. Even when the protective coat 15 is partially permeated into the gaps formed between the CNT fibers 8 forming the CNT film 14, it is possible to prevent damage / breakage of the CNT film 14 due to unexpected contact with other matters, to prevent foreign matters from entering into the gaps between the CNT fibers 8, and to suppress m...

first example

(A) First Example

(1-1) First Step

[0097]A slide glass is dipped in latex (i.e. natural rubber latex) and then dried for eight hours at the ambient temperature. Thus, it is possible to produce rubber substrates, having a rectangular shape in plan view, on both sides of the slide glass.

(1-2) Second Step

[0098]Next, conductive rubber adhesives are applied to the opposite ends of the substrate in the longitudinal direction, thus forming a pair of first conductive layers. Subsequently, a pair of electrodes is laminated on the surfaces of the first conductive layers. Herein, mesh electrodes are used as upper electrodes.

(1-3) Third Step

[0099]Next, a plurality of CNT fibers is wound about the slide glass in the width direction, thus forming a CNT film. At this time, the opposite ends of the slide glass in the width direction are masked using masking tapes.

[0100]In this connection, a plurality of CNT fibers is directly pulled out without twining crystals of CNT molecules, which are grown with ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
thicknessaaaaaaaaaa
thicknessaaaaaaaaaa
thicknessaaaaaaaaaa
Login to View More

Abstract

A strain sensor includes a flexible substrate, a CNT film made of a plurality of CNT fibers aligned in an orientation direction, a pair of electrodes, and a protective coat. The electrodes are formed at the opposite ends of the CNT film in a perpendicular direction to the orientation direction of the CNT fibers. The protective coat protecting the CNT film is made of a resin, a water-based emulsion, or an oil-based emulsion. The protective coat is placed in contact with at least part of the CTN fibers on the surface of the CNT film. The strain sensor including the protective coat is able to prevent damage / breakage of the CNT film and to prevent foreign matters from entering into gaps between CNT fibers, thus improving durability in maintaining adequate sensing functionality.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a strain sensor detecting displacement, impact, stress, strain, deformation, and / or distortion on materials, objects, matters, and / or substances, and in particular to a strain sensor using carbon nanotubes.[0003]The present application claims priority on Japanese Patent Application No. 2011-249172, the entire content of which is incorporated herein by reference.[0004]2. Description of the Related Art[0005]Conventionally, strain sensors are designed to detect strain based on resistance variations, e.g. resistances of resistors which are varied due to strain (e.g. expansion and contraction) applied thereto. Generally, metals or semiconductors have been used for resistors. However, metals or semiconductors have limitations when applied to strain sensors because they may produce a small amount of strain due to reversible expansion and contraction.[0006]Considering this drawback, various devi...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(United States)
IPC IPC(8): G01B7/16
CPCG01B7/18
Inventor SUZUKI, KATSUNORISAKAKIBARA, SHINGOYATAKA, KOJIOKUMIYA, YASUROTERADA, YOSHIKIINOUE, YOKU
Owner YAMAHA CORP