阅读说明：本技术 力传感器及其制造方法 (Force sensor and method for manufacturing the same ) 是由 冯雪 张柏诚 陈颖 付浩然 蒋晔 刘兰兰 于 2018-05-30 设计创作，主要内容包括：本发明公开了一种力传感器及其制造方法,涉及检测技术领域,所述力传感器包括：柔性基底、形成于所述柔性基底内的至少一个腔体、及设于所述腔体内壁的至少两个电极；所述腔体内填充有液态金属或胶态金属,所述液态金属或所述胶态金属将至少两个所述电极电连通。采用本发明实施例提供的技术方案,避免了现有技术中金属因多次弯折而发生非弹性形变的现象,提高了力检测的可靠性,更利于实现运动检测。(the invention discloses a force sensor and a manufacturing method thereof, relating to the technical field of detection, wherein the force sensor comprises: the flexible electrode structure comprises a flexible substrate, at least one cavity formed in the flexible substrate and at least two electrodes arranged on the inner wall of the cavity; the cavity is filled with a liquid metal or a colloidal metal that electrically communicates at least two of the electrodes. By adopting the technical scheme provided by the embodiment of the invention, the phenomenon of inelastic deformation of metal due to repeated bending in the prior art is avoided, the reliability of force detection is improved, and the motion detection is more favorably realized.)

1. a force sensor, comprising:

The flexible electrode structure comprises a flexible substrate, at least one cavity formed in the flexible substrate and at least two electrodes arranged on the inner wall of the cavity; the cavity is filled with a liquid metal or a colloidal metal that electrically communicates at least two of the electrodes.

2. The force sensor of claim 1, wherein the at least two electrodes comprise at least one electrode disposed at a top of the cavity and at least one electrode disposed at a bottom of the cavity; or

The at least two electrodes comprise at least two electrodes arranged on the side wall of the cavity.

3. the force sensor of claim 1, wherein the at least two electrodes are disposed on a top of the cavity; or

the at least two electrodes are arranged at the bottom of the cavity.

4. The force sensor of claim 1, wherein the at least two electrodes comprise at least one electrode disposed on a sidewall of the chamber and at least one electrode disposed on a top of the chamber; or

The at least two electrodes comprise at least one electrode arranged on the side wall of the cavity and at least one electrode arranged at the bottom of the cavity.

5. The force sensor of any one of claims 1-4, wherein the number of the cavities is plural, and the plural cavities are arranged in the flexible substrate at intervals.

6. The force sensor of claim 5, wherein a plurality of the cavities are aligned along a straight line; or a plurality of the cavities are arranged in an array; or one of the cavities is positioned at the center, and the rest cavities are arranged along the circumference which takes the center as the circle center.

7. The force sensor according to any one of claims 1-4, wherein the surface of the flexible substrate is provided with at least one protrusion, the protrusion being arranged in correspondence with at least one of the cavities.

8. the force sensor of claim 7, wherein the number of cavities is twice the number of projections, each projection being disposed with respect to two of the cavities, the tops of the two cavities being proximate the edges of the respective projections.

9. The force sensor of any one of claims 1-4, wherein the electrode is a deformable electrode.

10. The force sensor of claim 9, wherein the electrode is a mesh structure.

11. The force sensor of any one of claims 1-4, wherein the material of the flexible substrate is PDMS, PET or PI; and/or

The electrode is made of simple metal, ITO, AZO, carbon nano tubes or graphene.

12. a method of manufacturing a force sensor, comprising:

providing a first flexible substrate;

Providing a second flexible substrate, and forming at least one groove on the surface of the second flexible substrate, wherein the groove can be matched with the first flexible substrate to form a corresponding cavity;

forming at least two electrodes on the inner wall of the cavity;

hermetically connecting the first flexible substrate with the second flexible substrate; the cavity is filled with liquid metal or colloidal metal.

13. The method of manufacturing a force sensor according to claim 12, wherein the method of forming at least two electrodes on the cavity inner wall comprises:

forming a first electrode on the surface of the first flexible substrate;

And forming a second electrode at the bottom of the groove.

14. the method of claim 12 or 13, wherein the liquid metal or the colloidal metal is injected into the sealed cavity by injection.

15. The method of manufacturing a force sensor according to claim 12 or 13, wherein the liquid metal or the colloidal metal is injected into the groove before sealing.

16. The method of manufacturing a force sensor of claim 12, wherein the providing a first flexible substrate comprises:

Providing a first pristine flexible substrate;

and forming a protrusion on the first original flexible substrate by adopting a subtraction process to obtain a first flexible substrate with the protrusion on the surface.

17. The method of claim 12, wherein the electrodes are formed on the inner wall of the cavity by 3D printing.

Technical Field

the invention relates to the technical field of detection, in particular to a force sensor and a manufacturing method thereof.

Background

the force sensor can acquire pressure signals and convert the pressure signals into electric signals according to a certain rule. Existing force sensors generally use gold, silver, copper, or other noble metals capable of elastic deformation as a probe to acquire a pressure signal through deformation. However, after the metal is bent for many times, stress is accumulated, and metal fatigue is generated; after exceeding a certain deformation range, the metal can generate inelastic deformation and cannot be recovered to the initial state; for example, when the force sensor is applied to motion detection, metal is prone to inelastic deformation due to a large number of bending times, and thus a large measurement error is caused.

disclosure of Invention

Accordingly, there is a need for a force sensor and a method of manufacturing the same that can improve the reliability of force sensing.

According to a first aspect of embodiments of the present invention, there is provided a force sensor comprising:

The flexible substrate, at least one cavity formed in the flexible substrate and at least two electrodes arranged on the inner wall of the cavity; the cavity is filled with a liquid metal or a colloidal metal that electrically communicates at least two of the electrodes.

In an alternative embodiment, the at least two electrodes comprise at least one electrode disposed at the top of the chamber and at least one electrode disposed at the bottom of the chamber; or

the at least two electrodes comprise at least two electrodes arranged on the side wall of the cavity.

in an alternative embodiment, the at least two electrodes are disposed on the top of the chamber; or

The at least two electrodes are arranged at the bottom of the cavity.

in an alternative embodiment, the at least two electrodes include at least one electrode disposed on a sidewall of the chamber and at least one electrode disposed on a top of the chamber; or

The at least two electrodes comprise at least one electrode arranged on the side wall of the cavity and at least one electrode arranged at the bottom of the cavity.

In an alternative embodiment, the number of the cavities is multiple, and the multiple cavities are arranged in the flexible substrate at intervals.

In an alternative embodiment, a plurality of the cavities are arranged along a straight line; or a plurality of the cavities are arranged in an array; or one of the cavities is positioned at the center, and the rest cavities are arranged along the circumference which takes the center as the circle center.

in an alternative embodiment, the surface of the flexible substrate is provided with at least one protrusion, and the protrusion is arranged corresponding to at least one cavity.

In an alternative embodiment, the number of the cavities is twice the number of the protrusions, each protrusion is disposed corresponding to two cavities, and the tops of the two cavities are close to the edges of the corresponding protrusions.

In an alternative embodiment, the electrode is a deformable electrode.

In an alternative embodiment, the electrode is a mesh structure.

In an alternative embodiment, the material of the flexible substrate is PDMS, PET or PI; and/or

The electrode is made of simple metal, ITO, AZO, carbon nano tubes or graphene.

According to a second aspect of embodiments of the present invention, there is provided a manufacturing method of a force sensor, the manufacturing method including:

Providing a first flexible substrate;

Providing a second flexible substrate, and forming at least one groove on the surface of the second flexible substrate, wherein the groove can be matched with the first flexible substrate to form a corresponding cavity;

Forming at least two electrodes on the inner wall of the cavity;

Hermetically connecting the first flexible substrate with the second flexible substrate; the cavity is filled with liquid metal or colloidal metal.

In an alternative embodiment, the method of forming at least two electrodes on the inner wall of the chamber includes:

Forming a first electrode on the surface of the first flexible substrate;

and forming a second electrode at the bottom of the groove.

In an alternative embodiment, the liquid metal or the colloidal metal is injected into the sealed groove by injection.

In an alternative embodiment, the liquid metal or the colloidal metal is injected into the groove before sealing.

In an alternative embodiment, the providing a first flexible substrate comprises:

Providing a first pristine flexible substrate;

And forming a protrusion on the first original flexible substrate by adopting a subtraction process to obtain a first flexible substrate with the protrusion on the surface.

In an optional embodiment, the electrode is formed on the inner wall of the cavity by a 3D printing method.

Compared with the prior art, the invention has the following outstanding beneficial effects:

the invention provides a force sensor and a manufacturing method thereof.A variable resistance unit is constructed in a flexible substrate by electrically communicating at least two electrodes through liquid metal or colloidal metal, so that the liquid metal or the colloidal metal acts as a conductive medium between the at least two electrodes; by adopting the force sensor provided by the invention, the action of an external force on the flexible substrate can be converted into the stretching or compressing of the flexible substrate on the cavity, and the deformation of the cavity causes the distance between at least two electrodes to change, so that the resistance value of the variable resistance unit changes, and the detection of the force can be realized by determining the change of the resistance value or determining the change of an electric signal caused by the change of the resistance value. Because the deformation of the cavity is determined by the deformation capacity of the flexible substrate and is not limited by the stretching performance of the metal, the force sensor provided by the embodiment avoids the phenomenon of measurement error caused by inelastic deformation of the metal in the prior art, improves the reliability of force detection, and is more beneficial to realizing motion detection.

drawings

FIG. 1 is a cross-sectional view of a force sensor provided in accordance with an embodiment of the present invention;

FIG. 2 is a front view of a force sensor provided in accordance with an embodiment of the present invention;

FIG. 3 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 4 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 5 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 6 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 7 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 8 is a front view of the force sensor of FIG. 7 under a longitudinal force F1;

FIG. 9 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 10 is a front view of the force sensor of FIG. 9 under a longitudinal force F1;

FIG. 11 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 12 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 13 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 14 is a front view of the force sensor of FIG. 13 under a longitudinal force F1;

FIG. 15 is a front view of the force sensor of FIG. 13 under a lateral force F2;

FIG. 16 is a front view of a force sensor provided in accordance with yet another embodiment of the present invention;

FIG. 17 is a top view of a force sensor provided in accordance with yet another embodiment of the present invention;

fig. 18 is a flowchart of a method for manufacturing a force sensor according to a second embodiment of the present invention;

FIG. 19 is a schematic view of a first raw flexible substrate 11 in a method of manufacturing a force sensor provided by an embodiment of the invention;

FIG. 20 is a schematic diagram illustrating a first step of a method of manufacturing a force sensor according to an embodiment of the present invention;

FIG. 21 is a schematic diagram of step two of a method of manufacturing a force sensor according to an embodiment of the invention;

FIG. 22 is a schematic diagram illustrating a third step of a method for manufacturing a force sensor according to an embodiment of the present invention;

FIG. 23 is a schematic diagram illustrating a fourth step of a method of manufacturing a force sensor according to an embodiment of the present invention;

fig. 24 is a schematic diagram of step five of the method for manufacturing a force sensor according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the relevant aspects of the present invention are shown in the drawings.

in the description of the embodiment of the present invention, the descriptions of the top, the bottom, and the side walls are defined with respect to fig. 1, and if the orientation of the cavity in fig. 1 changes, the descriptions of the top, the bottom, and the side walls will also change according to the change of the orientation of the cavity, which is not repeated herein.