US-12618726-B2 - Strain-insensitive tactile sensor with high sensitivity and wide sensing range using stretchable sensor array

US12618726B2US 12618726 B2US12618726 B2US 12618726B2US-12618726-B2

Abstract

Provided is a tension-insensitive tactile sensor having high sensitivity and a wide sensing range by using a stretchable sensor array. According to the stretchable sensor array and the method for manufacturing the same of the present invention, pressure may be measured without interference of tension while maintaining flexibility of the sensor. In addition, the stretchable sensor array may have high initial resistance, induce a large change in contact resistance when pressure is applied, thereby being capable of measuring pressure with high sensitivity, have a wide pressure sensing range, and have decreased interference by an when sensing a pressure distribution.

Inventors

Jongbaeg Kim
Minhyeong KIM
Kyubin BAE

Assignees

INDUSTRY-ACADEMIC COOPERATION FOUNDATION, YONSEI UNIVERSITY

Dates

Publication Date: 20260505
Application Date: 20230106
Priority Date: 20220106

Claims (10)

1 . A stretchable sensor array comprising: a polymer matrix including a first elastomer and having a plurality of holes; and a plurality of cells which are filled into the plurality of holes and include a convex portion protruding outward on one or more surfaces of the polymer matrix, wherein the polymer matrix is stretchable, wherein the first elastomer is silicone-based elastomer, wherein the plurality of cells includes a conductive composite including conductive particles and a second elastomer, and wherein a Young's modulus of the conductive composite is higher than a Young's modulus of the polymer matrix.
2 . The stretchable sensor array of claim 1 , wherein the convex portion protruding on the surface of the polymer matrix has a height of 0.1 to 1 mm.
3 . The stretchable sensor array of claim 1 , wherein the cells have a decreased thickness with compression.
4 . The stretchable sensor array of claim 1 , wherein the first elastomer and the second elastomer are a silicon-based elastomer.
5 . The stretchable sensor array of claim 1 , wherein the conductive particles are a conductive carbonaceous material.
6 . The stretchable sensor array of claim 5 , wherein the conductive carbonaceous material is a carbon nanotube.
7 . The stretchable sensor array of claim 1 , wherein the conductive particles are included at 0.1 to 15 wt % with respect to the conductive composite.
8 . The stretchable sensor array of claim 1 , wherein the stretchable sensor array senses pressure to generate an electrical signal.
9 . A tactile sensor comprising: an upper electrode; the stretchable sensor array of claim 1 in electrical contact with the upper electrode; and a lower electrode in electrical contact with the stretchable sensor array.
10 . The tactile sensor of claim 9 , wherein the tactile sensor has a sensitivity (S=(Δl/l 0 )/Δp) of 0.8 kPa −1 or more.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of Korean Patent Application No. 10-2022-0002026, filed on Jan. 6, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD The following disclosure relates to a tactile sensor which has high sensitivity and a wide sensing range and is insensitive to tension by using a stretchable sensor array. BACKGROUND The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Human skin is a complex sensory perception organ interacting with an external environment, and in order to imitate this, a tactile sensor which imitates tactility for perceiving an external physical stimulus is being developed. A tactile sensor responds to physical stimuli such as pressure, tension, and bending, and converts a physical stimulus signal into an electrical or digital signal and perceives the signal. Since the tactile sensor has different element structures depending on the kinds of converted electrical signals and application fields to be applied, it may be implemented in various shapes, and for example, when it is used in a wearable sensor, flexibility and softness are required, and when it is used in a terminal, miniaturization, light weight, and the like are required. A tactile sensor developed so far includes a resistive type, a capacitive type, an infrared proximity type, a piezoelectric type, and the like. Since among them, a stretchable tactile sensor may easily measure pressure through a resistance method due to its simple structure, many studies have been conducted, and in particular, studies to increase sensitivity are receiving a lot of attention. However, since the tactile sensor as such has problems such as low sensitivity, a limited pressure measurement range, and non-uniform sensor characteristics, development of a flexible tactile sensor which has low hysteresis, uniform sensor characteristics, a large pressure measurement range, and high sensitivity as compared with the conventional tactile sensor is demanded. SUMMARY An embodiment of the present invention is directed to providing a stretchable sensor array which may measure pressure without interference of tension while maintaining flexibility of a sensor. Another embodiment of the present invention is directed to providing a stretchable sensor array which has high initial resistance and induces a large change in contact resistance when pressure is applied, thereby being capable of measuring pressure with high sensitivity. Another embodiment of the present invention is directed to providing a stretchable sensor array which has a wide pressure sensing range and also has decreased interference by an adjacent cell when sensing a pressure distribution. Still another embodiment of the present invention is directed to provide a method for manufacturing a flexible stretchable sensor array having a large area easily and rapidly. In one general aspect, a stretchable sensor array includes: a polymer matrix including a first elastomer and having a plurality of holes; and a plurality of cells which are filled into the plurality of holes and include a convex portion protruding outward on one or more surfaces of the polymer matrix, wherein the plurality of cells includes a conductive composite including conductive particles and a second elastomer. In the stretchable array of the present invention, the convex portion protruding on the surface of the polymer matrix may have a height of 0.1 to 1 mm. In the stretchable array of the present invention, the cell may have a decreased thickness with compression. In the stretchable array of the present invention, the first elastomer and the second elastomer may be a silicon-based elastomer. In the stretchable array of the present invention, the conductive particles may be a conductive carbonaceous material, and the conductive carbonaceous material may be a carbon nanotube. In the stretchable array of the present invention, the conductive particles may be included at 0.1 to 15 wt % with respect to the conductive composite, and the Young's modulus of the conductive composite may be higher than the Young's modulus of the first elastomer. In the stretchable array of the present invention, the stretchable sensor array senses pressure to generate an electrical signal. In another general aspect, a tactile sensor includes: an upper electrode; a stretchable sensor array of claim 1 in electrical contact with the upper electrode; and a lower electrode in electrical contact with the stretchable sensor array. In the tactile sensor of the present invention, the tactile sensor may have a sensitivity (S=(Δl/l0)/Δp) of 0.8 kPa−1 or more. In still another general aspect, a method for manufacturing a stretchable sensor array includes: (a) stretching a polymer matrix including a first elastomer and having a p