Shared Driver IC for Dual SMA Camera Actuators
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Solution Overview
Problem
High-performance actuators for camera modules in mobile devices are costly when used individually, especially for dual camera setups requiring both optical image stabilization and auto-focusing functions.
Innovation Solution
The use of a shared driver integrated chip (IC) to simultaneously drive shape memory alloy (SMA) wire groups for both lens modules, with a driver circuit generating the same driving signal for SMA wires connected to different lens modules, and a position detector to measure thermal resistances for precise positioning, reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate driver ICs are used for each lens module to enable high-performance auto-focusing and optical image stabilization, then the actuator performance is improved, but the system cost increases excessively
Solution Approach 1:
The patent merges the driving functions for multiple lens modules into a single driver IC. The driver IC includes a driving circuit that can simultaneously drive SMA wires for both the first lens module (auto-focusing) and the second lens module (optical image stabilization), eliminating the need for separate driver ICs and reducing system cost.
Solution Approach 2:
The driver IC is designed with multi-functionality to perform multiple roles: it drives SMA wires for auto-focusing in the first lens module, drives SMA wires for optical image stabilization in the second lens module, and coordinates both functions simultaneously. This universal design reduces component count and system cost while maintaining high performance.
2Ease of manufacture
If a shared driver IC is used to reduce system cost, then manufacturing cost is reduced, but the complexity of signal management and position detection increases
Solution Approach 1:
The driver IC internally segments different driving functions into separate circuits: a first driving circuit for auto-focusing SMA wires and a second driving circuit for optical image stabilization SMA wires. This segmentation allows independent control of each function while using a single shared driver IC, simplifying signal management.
Solution Approach 2:
The position detector acts as an intermediary that sequentially measures thermal resistances of SMA wires for both lens modules and provides position information to the controller. This intermediary component simplifies the control logic by centralizing position detection and coordination functions within the shared driver IC.
3Ease of manufacture
If sequential driving signals are used to share the driver IC, then component cost is reduced, but the response time for simultaneous lens module control may be affected
Solution Approach 1:
The driver IC uses periodic action by sequentially switching between driving different lens modules at different time periods. The controller coordinates the timing of driving signals for the first and second lens modules, ensuring that both receive appropriate driving signals in sequence while maintaining overall system responsiveness.
Solution Approach 2:
The driver IC dynamically adjusts its operation mode based on real-time requirements. It can switch between simultaneously driving both lens modules when both functions are needed, or sequentially driving them when only one function is active, optimizing response time while maintaining cost efficiency.
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 solution reduces the overall system cost by sharing the driver IC and improves efficiency in driving signals and position detection, enabling precise auto-focusing and optical image stabilization in dual camera modules.
Implementation Method 1
a shape memory alloy (SMA) wire group comprising first SMA wires driving a first lens module and second SMA wires driving a second lens module
Implementation Method 2
a shape memory alloy (SMA) wire group comprising first SMA wires driving a first lens module and second SMA wires driving a second lens module
Implementation Method 3
a position detector configured to measure thermal resistances from the first SMA wires driving the first lens module and the second SMA wires driving the second lens module to detect positions of the first lens module and the second lens module
Data Source
AI summary
An actuator of a camera module includes a shape memory alloy (SMA) wire group and a driver. The shape memory alloy (SMA) wire group includes first SMA wires driving a first lens module and second SMA wires driving a second lens module. The driver configured to drive a pair of SMA wires driving different lens modules of the first and the second lens modules among the first and the second SMA wires in a same scheme.