Piezoelectric Lens Drive Shock Compensation

Solution Overview

Problem

Miniaturized camera units with piezoelectric elements face issues with external shocks causing lens misalignment, leading to incorrect zoom magnification and focus, which existing mechanisms struggle to address without increasing device size and complexity.

Innovation Solution

Incorporating a piezoelectric element that deforms with voltage to adjust lens position, with a detector to sense external shocks and a controller to reposition the lens, allowing for precise adjustment and maintaining correct focus and zoom without additional space-consuming mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a vibration type actuator using piezoelectric element is used to move the lens, then the camera unit can be further lightened and miniaturized, but the lens becomes vulnerable to external shocks causing positional misalignment

Engineering Contradiction:

Improvecamera unit sizeVSAvoidlens position stability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The piezoelectric element serves dual functions: it acts as both the driving actuator for lens movement and the sensor for detecting external shocks. When an external shock is detected through voltage generation, the controller uses the same piezoelectric element to return the lens to its correct position, eliminating the need for separate actuator and sensor components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system implements a feedback mechanism where the piezoelectric element detects external shocks through generated voltage, and the controller responds by adjusting the lens position back to the correct state. This closed-loop control ensures lens position stability despite the compact design vulnerabilities.

Inventive Principle:

Principle #23Feedback

2Reliability

If a mechanism for fixing the lens at the correct position is provided to overcome external shock problems, then lens position stability is improved, but the lens drive device becomes enlarged and control becomes complicated

Engineering Contradiction:

Improvelens position stabilityVSAvoidlens drive device complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The piezoelectric element serves dual functions: it acts as both the driving actuator for lens movement and the sensor for detecting external shocks. When an external shock is detected through voltage generation, the controller uses the same piezoelectric element to return the lens to its correct position, eliminating the need for separate actuator and sensor components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the actuator and sensor functions into a single piezoelectric element. The driving unit and detection unit are combined, reducing the number of components and simplifying the overall lens drive device structure while maintaining reliable shock compensation.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If a separate detection mechanism is added to detect external shocks, then lens position accuracy is improved, but the device size and weight increase

Engineering Contradiction:

Improveexternal shock detection accuracyVSAvoidcamera unit weight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

The piezoelectric element serves dual functions: it acts as both the driving actuator for lens movement and the sensor for detecting external shocks. When an external shock is detected through voltage generation, the controller uses the same piezoelectric element to return the lens to its correct position, eliminating the need for separate actuator and sensor components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Effectively prevents lens misalignment due to external shocks by using the same piezoelectric element for both lens adjustment and shock detection, ensuring accurate zoom and focus while minimizing device size and weight.

Implementation Method 1

an adjust unit which has a piezoelectric element, deforms the piezoelectric element with a voltage applied thereto, and adjusts a distance between the lens and the image unit

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a first detector which detects an electric signal generated by deformation of the piezoelectric element after adjustment by the adjust unit

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS7738198B2Imaging device, lens drive control method and recording medium

Publication Date: 2010.06.15 LENOVO INNOVATIONS LTD (HONG KONG)

AI summary

A controller controls a drive waveform generator to apply a predetermined voltage to a piezoelectric element and deform the piezoelectric element, thereby moving a lens. The controller acquires the position of the lens based on a magnetic field intensity detected by a Hall device. A shock detection circuit measures a voltage generated by deformation of the piezoelectric element caused by an external shock. The controller determines whether or not the voltage measured by the shock detection circuit is larger than a predetermined threshold, and detects positional misalignment of the lens. When detecting the positional misalignment, the controller resets the lens at a position acquired before the shock was applied.