Flexible piezoelectric composite films, flexible piezoelectric impact sensors, pedestrian protection systems, and related methods

Patent metadata

Field	Value
Publication number	US-12534043-B2
Application number	US-202318523977-A
Country	US
Kind code	B2
Filing date	Nov 30, 2023
Priority date	Nov 30, 2022
Publication date	Jan 27, 2026
Grant date	Jan 27, 2026

Abstract

Flexible piezoelectric composite films, flexible piezoelectric impact sensors, pedestrian protection systems, and related methods. Such a flexible piezoelectric composite film includes a flexible matrix and a plurality of piezoelectric particles dispersed and embedded within the flexible matrix. The piezoelectric particles are arranged in columns aligned in a Z-direction along a thickness of the flexible matrix.

First claim

The invention claimed is:

1 . A flexible piezoelectric impact sensor comprising:
a flexible piezoelectric composite film comprising a flexible matrix and a plurality of piezoelectric particles dispersed and embedded within the flexible matrix, wherein the piezoelectric particles are arranged in columns aligned in a Z-direction along a thickness of the flexible matrix; a first flexible electrode disposed on a first side of the flexible piezoelectric composite film; and a second flexible electrode disposed on a second side of the flexible piezoelectric composite film opposite the first side; wherein each of the first flexible electrode and the second flexible electrode comprises electrically conductive particles embedded within a flexible matrix; and wherein the flexible matrix of the flexible electrodes is the same as the flexible matrix of the flexible piezoelectric composite film.

2 . The flexible piezoelectric impact sensor of claim 1 , wherein the piezoelectric particles comprise a piezoelectric ceramic material.

3 . The flexible piezoelectric impact sensor of claim 2 , wherein the piezoelectric ceramic material comprises lead zirconate titanate.

4 . The flexible piezoelectric impact sensor of claim 1 , wherein the flexible matrix comprises at least one of a polymer matrix and an epoxy matrix.

5 . The flexible piezoelectric impact sensor of claim 4 , wherein the polymer matrix comprises polydimethylsiloxane (PDMS).

6 . The flexible piezoelectric impact sensor of claim 1 , further comprising an electrical interconnect coupled to the first flexible electrode.

7 . The flexible piezoelectric impact sensor of claim 1 , wherein the flexible piezoelectric impact sensor is moldable to a shape of a bumper fascia without prior shaping during manufacture of the flexible piezoelectric impact sensor.

8 . The flexible piezoelectric impact sensor of claim 1 , wherein the flexible piezoelectric impact sensor is operable to sense impacts without electrical power input.

9 . A pedestrian protection system implemented on an automobile, the pedestrian protection system comprising:
a bumper assembly on the automobile; a flexible piezoelectric impact sensor in accordance with claim 1 coupled to the bumper assembly; and a pedestrian protective measure, wherein the pedestrian protective measure is configured to be activated when the flexible piezoelectric impact sensor senses an impact with a pedestrian.

10 . The pedestrian protection system of claim 9 , wherein the pedestrian protective measure is configured to not be activated when the flexible piezoelectric impact sensor senses an impact with a non-human object.

11 . A method of producing an impact sensor with a flexible piezoelectric composite film, the method comprising:
combining piezoelectric particles and graphite nanoplatelet particles in a polymer resin; mixing the piezoelectric particles, the graphite nanoplatelet particles, and the polymer resin to form a substantially homogenous dispersion; adding a hardener to the substantially homogeneous dispersion to form a slurry; casting the slurry into a substantially two-dimensional cast sheet having a thickness; applying an electrical field to the cast sheet to align the piezoelectric particles and the graphite nanoplatelet particles in columns aligned in a Z-direction along the thickness of the cast sheet; curing the cast sheet while maintaining the electrical field to form the flexible piezoelectric composite film having the piezoelectric particles and the graphite nanoplatelet particles embedded in a polymer matrix formed by the polymer resin; forming an impact sensor from the piezoelectric particles; and tuning performance of the impact sensor by adjusting the modulus of the polymer matrix to improve discrimination ability of the impact sensor.

12 . The method of claim 11 , wherein the piezoelectric particles comprise a piezoelectric ceramic material.

13 . The method of claim 12 , wherein the piezoelectric ceramic material comprises lead zirconate titanate.

14 . The method of claim 11 , wherein the polymer resin comprises polydimethylsiloxane (PDMS) resin.

15 . The method of claim 11 , wherein the step of applying an electrical field comprises applying about 1 kV/mm at 100 Hz.

16 . The method of claim 11 , wherein the step of curing comprises curing at a temperature of approximately 80° C.

Assignees

• Purdue Research Foundation

Inventors

• Cakmak Mukerrem
• Yildirim Armen
• Grant Jesse
• Ghannam Mahmoud Yousef
• Vidyanag Nagarpita

Classifications

• H10N30/878

  the principal material being non-metallic, e.g. oxide or carbon based · CPC title

• H10N30/852

  Composite materials, e.g. having 1-3 or 2-2 type connectivity · CPC title

• H10N30/302

  Sensors · CPC title

• H10N30/092

  Forming composite materials · CPC title

• H10N30/04 Primary

  Treatments to modify a piezoelectric or electrostrictive property, e.g. polarisation characteristics, vibration characteristics or mode tuning · CPC title