SMA Motor Camera Module Actuation for Low Power Autofocus

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional camera modules with voice coil motors consume high power due to the heavy load required for auto focus and optical image stabilization, leading to increased power consumption and magnetic interference.

Innovation Solution

A camera module utilizing a shape memory alloy (SMA) motor that actuates the image sensor to shift parallel or tilt relative to the optical axis, reducing the actuation load and power consumption, and eliminating magnetic interference by using non-electromagnetic forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a voice coil motor is used to actuate the camera lens for auto focus and optical image stabilization, then the camera lens can be shifted to adjust focus and stabilize images, but the power consumption increases due to the heavy load of actuating the camera lens, actuating members, and carrier simultaneously

Engineering Contradiction:

Improveauto focus and optical image stabilization functionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent divides the actuation system into two independent parts: the camera lens remains fixed while only the image sensor is actuated by the voice coil motor. This segmentation separates the heavy lens from the lighter sensor, significantly reducing the load and power consumption while maintaining focus and stabilization functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of the conventional approach where the camera lens is actuated to achieve focus and stabilization, this patent inverts the system by fixing the lens and actuating the image sensor in reverse. This inversion transfers the actuation burden from the heavy lens to the lighter sensor, reducing power consumption while achieving the same optical effects.

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If a voice coil motor with five pairs of actuating members is used to implement both auto focus and optical image stabilization, then both functions can be achieved, but the device complexity increases due to the multiple magnets and coils required

Engineering Contradiction:

Improvedual function of auto focus and optical image stabilizationVSAvoidmotor structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the voice coil motor universal by using the same actuating members (one magnet and one coil per pair) to perform both auto focus and optical image stabilization functions. By fixing the camera lens and actuating the image sensor, a single set of actuating members can achieve both functions, eliminating the need for separate mechanisms and reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Force

If electromagnetic forces are used to actuate the camera lens and actuating members, then the required force can be generated, but magnetic interference is produced that may affect other components

Engineering Contradiction:

Improveactuation forceVSAvoidmagnetic interference

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the camera lens from the actuation system, keeping it fixed while only actuating the image sensor. This extraction eliminates the need for strong electromagnetic forces required to move the heavy lens, thereby reducing magnetic interference. The same voice coil motor can then generate sufficient force with minimal electromagnetic interference to actuate only the lighter image sensor.

Inventive Principle:

Principle #2Taking out (Extraction)

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

The SMA motor achieves low power consumption and improved performance in auto focus and optical image stabilization with a simplified motor structure, reducing the compensated distance and angle required for image stabilization, while eliminating the need for Hall sensors and complex prism actuating motors.

Implementation Method 1

Methodology Applied

Scientific EffectShape memory alloy effect: Shape Memory Alloy

Data Source

PatentUS12015849B2Camera module and electronic device

Publication Date: 2024.06.18 HUAWEI TECH CO LTD

AI summary

A camera system includes a module frame, a camera lens, an image sensor, and an SMA motor that are stacked within the module frame. The camera lens is fixedly connected to the module frame, and the SMA motor is located on an out-light side of the camera lens. The image sensor is located between the camera lens and the SMA motor and is fastened to the SMA motor. The SMA motor is configured to actuate the image sensor to shift in a direction parallel to an optical axis of the camera lens. The SMA motor is further configured to actuate the image sensor to shift on a plane perpendicular to the optical axis of the camera lens.