Camera Module SMA Compensation for Thermal Focus Drift
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Solution Overview
Problem
Existing camera modules with plastic or glass-plastic hybrid lens assemblies suffer from significant temperature-induced deformation, leading to changes in focal length and defocus, which degrade image quality due to the inability of existing solutions to maintain the lens and image sensor in a quasi-focus position.
Innovation Solution
A camera module with a temperature drift compensation assembly using a shape memory alloy (SMA) to drive axial movement of the lens assembly, compensated by a control assembly that adjusts based on temperature changes, maintaining the lens and image sensor in a quasi-focus position without increasing cost or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plastic or glass-plastic hybrid lens assembly is used, then manufacturing cost is reduced, but temperature-induced deformation occurs leading to defocus and degraded image quality
Solution Approach 1:
The patent uses shape memory alloy to change its physical state (shape) in response to temperature changes, thereby compensating for thermal deformation of the lens assembly. The shape memory alloy transforms between martensite and austenite phases, enabling active compensation of temperature-induced focal length changes while maintaining low manufacturing cost of the lens assembly.
Solution Approach 2:
The patent implements a feedback control system where a temperature sensor detects temperature changes and sends signals to a control module, which then activates the shape memory alloy to compensate for thermal deformation. This closed-loop feedback mechanism ensures the lens assembly maintains focus despite temperature variations, resolving the contradiction between cost-effective plastic lenses and image quality.
2Manufacturing precision
If voice coil motors or excessive glass lenses are used for temperature compensation, then image clarity is maintained, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical focus adjustment systems (voice coil motors) with a shape memory alloy-based compensation mechanism. The shape memory alloy directly transforms shape in response to temperature, eliminating the need for motors, gears, and complex mechanical assemblies, thereby maintaining image clarity while significantly reducing device complexity.
Solution Approach 2:
The patent exploits the phase transition properties of shape memory alloy between martensite and austenite phases to achieve focus compensation. This phase transition enables the alloy to change its shape and length in response to temperature changes, providing a simple yet effective mechanism for maintaining image clarity without complex mechanical systems.
3Manufacturing precision
If the lens assembly is made axially movable for focus adjustment, then image quality can be maintained, but device complexity increases
Solution Approach 1:
The patent enables the lens assembly to self-adjust its position through the shape memory alloy's automatic response to temperature changes. The shape memory alloy integrated into the lens holder automatically expands or contracts based on temperature, causing the lens assembly to move axially and maintain focus without requiring external motors or complex adjustment mechanisms, thus achieving focus accuracy with minimal structural complexity.
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 solution ensures high image clarity by maintaining the lens and image sensor in a quasi-focus position, reducing manufacturing costs, and being suitable for mass production without the need for voice coil motors or excessive glass lenses.
Implementation Method 1
the temperature drift compensation body being made of a shape memory alloy, the control signal being a current signal, and the shape memory alloy being deformable in response to the current signal
Implementation Method 2
the temperature drift compensation body being made of a shape memory alloy... the shape memory alloy being deformable in response to the current signal
Data Source
AI summary
The present application relates to the field of camera technology, and particularly relates to a camera module and an electronic device. The camera module comprises a base assembly; a lens assembly axially movably disposed on the base assembly; a temperature drift compensation assembly mounted to the base assembly, the temperature drift compensation assembly configured to be deformable to drive axial movement of the lens assembly relative to the base assembly; a control assembly electrically connected to the temperature drift compensation assembly, the control assembly configured to generate a control signal based on a temperature within the camera module, the temperature drift compensation assembly able to deform in response to the control signal.