Shape Memory Alloy Camera Shutter Actuator

Solution Overview

Problem

Conventional mechanical shutters for digital image sensors in compact electronic devices, such as smartphones and tablets, are bulky and add unnecessary size and weight, making them unsuitable for these applications.

Innovation Solution

The use of shape memory structures that transition from a lower-temperature shape to a higher-temperature shape upon heating, allowing for the creation of compact camera shutters with actuators that can be configured as loops, twisting, or linear mechanisms, enabling controlled aperture and shutter operation without the need for bulky mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional mechanical shutters are used in compact electronic devices, then the shutter can control light exposure for digital image sensors, but the device size and weight increase significantly

Engineering Contradiction:

Improveshutter functionVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces conventional bulky mechanical shutter mechanisms with shape memory alloy-based actuators that use thermally-induced shape changes to move the shutter. This substitution of mechanical actuation with smart material-based actuation dramatically reduces the size and weight while maintaining the shutter's light-blocking function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes changes in the physical state and shape of shape memory alloys in response to temperature variations to drive the shutter mechanism. By controlling the temperature parameter, the alloy transitions between different shapes, enabling compact actuation without traditional mechanical linkages.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional mechanical shutters are used in compact electronic devices, then the shutter can control light exposure for digital image sensors, but the device size and weight increase significantly

Engineering Contradiction:

Improveshutter functionVSAvoiddevice volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces conventional bulky mechanical shutter mechanisms with shape memory alloy-based actuators that use thermally-induced shape changes to move the shutter. This substitution of mechanical actuation with smart material-based actuation dramatically reduces the size and weight while maintaining the shutter's light-blocking function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The shape memory actuator is integrated directly into the shutter assembly, with the alloy wire or structure embedded within the shutter mechanism itself. This nested integration eliminates the need for separate actuator components and mounting structures, further compacting the overall device volume.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Adaptability or versatility

If shape memory structures with segments of different dimensions are used, then different portions of the structures exhibit shape transitions at different times enabling controlled aperture, but the device complexity increases

Engineering Contradiction:

Improvecontrolled apertureVSAvoidstructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shape memory actuator is divided into segments or sections with different dimensions, material properties, or geometric configurations. These segmented structures respond at different rates or to different temperature thresholds, enabling independent control of aperture size and shutter timing without requiring complex control systems.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the shape memory structure are designed with locally optimized properties such as varying wire diameters, thicknesses, or alloy compositions. This local differentiation allows specific regions to transition at different times, providing graded control over the aperture and shutter operation from a single integrated structure.

Inventive Principle:

Principle #3Local quality

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

Enables the integration of a mechanical shutter in compact electronic devices, effectively addressing the issue of size and weight while providing a reliable and efficient means to control light exposure for digital image sensors.

Implementation Method 1

shape memory structures may be provided with segments of different dimensions so that different portions of the structures exhibit shape transitions at different times

Methodology Applied

Scientific EffectShape memory effect: Shape Memory Alloy

Implementation Method 2

Shape memory wire may be configured to form a loop that heats upon application of a signal

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS8842215B2Electronic device with shape memory devices

Publication Date: 2014.09.23 APPLE INC

AI summary

An electronic device may be provided with shape memory structures. The shape memory structures may be used to form actuators for a camera shutter, an actuator for moving an optical filter, or other actuators in an electronic device. A camera shutter may have an opaque shutter member that is movable between a first position in which the shutter is closed and blocks light from a digital image sensor and a second position in which the shutter is open and allows light to reach the digital image sensor. The camera shutter may have an associated color filter structure. Shape memory wire may be configured to form a loop that heats upon application of a signal or may be configured to form a twisting or linear actuator. The camera shutter may be provided with a controllable aperture.