Piezoelectric Ink Traces for Flexible Substrates

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Solution Overview

Problem

Incorporating conventional piezoelectric components into electronic devices, such as mounting piezoelectric ceramic wafers onto flexible substrates, is challenging due to difficulties in achieving the desired output and integration.

Innovation Solution

The use of piezoelectric ink, where particles of piezoelectric material like lead zirconate titanate are dispersed in a binder, allows for deposition on various surfaces, including flexible and curved ones, enabling the creation of piezoelectric traces that can be used in input-output devices like speakers and keyboards, with control circuitry applying voltage to produce sound or haptic feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional piezoelectric ceramic wafers are used, then the piezoelectric output is achieved, but the difficulty of mounting on flexible substrates increases

Engineering Contradiction:

Improvepiezoelectric outputVSAvoidmounting difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the physical state of piezoelectric material from rigid ceramic wafers to a printable ink formulation containing piezoelectric particles dispersed in a binder. This parameter change allows the material to be deposited as a fluid or paste and then cured to form functional traces on flexible substrates, resolving the mounting difficulty while maintaining piezoelectric output

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining piezoelectric particles with a binder material to create a printable ink. This composite formulation allows the piezoelectric properties to be preserved while enabling new processing methods (printing/deposition) and substrate compatibility (flexible substrates) that are not achievable with conventional ceramic wafers

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If piezoelectric ink is used, then the ease of deposition on various surfaces is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvedeposition easeVSAvoidmanufacturing process complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical mounting processes (handling, positioning, and securing rigid ceramic wafers) with a deposition-based process where piezoelectric ink is printed or deposited directly onto the substrate. This substitution simplifies the manufacturing process by eliminating complex mechanical assembly steps while enabling deposition on complex geometries

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method facilitates the integration of piezoelectric components into electronic devices, enabling effective sound production and haptic feedback on diverse surfaces, including flexible and complex geometries, enhancing the functionality of input-output devices.

Implementation Method 1

Control circuitry may apply a voltage to the piezoelectric traces to cause the piezoelectric traces to vibrate the flexible membrane to produce sound

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

receive key press data that the piezoelectric traces produce in response to an applied force or touch

Methodology Applied

Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentUS10680161B1Electronic Devices with Piezoelectric Ink

Publication Date: 2020.06.09 APPLE INC

AI summary

An electronic device may have input devices and/or output devices based on piezoelectric components. Piezoelectric components may include piezoelectric ink in which particles of piezoelectric material are dispersed in a binder. The piezoelectric ink may be printed or otherwise deposited onto a substrate to form piezoelectric ink traces. The piezoelectric ink traces may be deposited on flexible substrates such as elastic speaker diaphragms or flexible fabric layers. The piezoelectric traces may be part of a key in a keyboard or a stand-alone button. In arrangements where the piezoelectric trace forms part of a key in a keyboard, the piezoelectric trace may be coupled to a grid of horizontal and vertical signal lines. The signal lines may convey key press data from the piezoelectric trace to control circuitry and/or may supply control signals from the control circuitry to the piezoelectric trace to produce haptic output.