SMA Actuator Wire Insulation for Miniature Camera Cooling
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Solution Overview
Problem
SMA actuator wires in miniature cameras are prone to short circuits when close to metal components, leading to potential damage and reduced performance due to local heating, and existing insulating solutions may compromise cooling rates necessary for rapid response in focus, zoom, and image stabilization applications.
Innovation Solution
Coating SMA actuator wires with an electrically insulating layer of thickness ranging from 0.3 μm to 10 μm to prevent short circuits while maintaining rapid cooling rates, achieved by balancing increased thermal resistance with enhanced heat loss to the surrounding air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrically insulating layer is added to the SMA actuator wire, then the risk of short circuits is reduced, but the rate of cooling of the wire is expected to decrease
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness of the electrically insulating layer to a specific range (0.3 μm to 10 μm). This parameter optimization ensures that the layer provides sufficient electrical insulation to prevent short circuits while maintaining thermal conductivity characteristics that allow rapid cooling of the SMA wire, thus resolving the contradiction between reliability and speed.
Solution Approach 2:
The patent applies local quality by selectively coating only the portions of the SMA actuator wire that are in close proximity to metal components or at different potentials. This localized insulation approach provides electrical protection precisely where short circuit risk exists, while leaving other portions of the wire uncovered to maintain optimal thermal exchange and cooling performance.
2Volume of moving object
If the SMA actuator wire is located close to metal components to reduce camera size, then the camera size is reduced, but the risk of short circuit increases
Solution Approach 1:
The patent applies the intermediary principle by introducing an electrically insulating layer as a mediator between the SMA actuator wire and nearby metal components. This insulating layer acts as an intermediate barrier that prevents direct electrical contact and potential short circuits, enabling the wire to be positioned close to metal components for miniaturization while maintaining system reliability.
3Reliability
If a thick electrically insulating layer is used, then electrical insulation is improved, but thermal resistance increases and cooling rate decreases
Solution Approach 1:
The patent applies parameter changes by establishing an optimal thickness range (0.3 μm to 10 μm) for the electrically insulating layer. Within this range, the layer provides adequate electrical insulation to prevent breakdown and short circuits, while the thickness remains sufficiently small to minimize thermal resistance and maintain rapid heat dissipation from the SMA wire during cooling cycles.
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 effectively reduces the risk of short circuits, allows for smaller camera designs, and maintains the necessary rapid response times for focus, zoom, and image stabilization by ensuring the SMA actuator wires can heat and cool quickly without significant thermal insulation drawbacks.
Implementation Method 1
the SMA actuator wire is coated with an electrically insulating layer of thickness in the range from 0.3 μm to 10 μm
Implementation Method 2
SMA actuator wires are known for use in miniature cameras to effect focus, zoom or optical image stabilization
Implementation Method 3
SMA (shape memory alloy) actuator wires to effect focus, zoom or optical image stabilization
Data Source
AI summary
A miniature camera (1) comprising at least one SMA actuator wire (11) arranged to effect focus, zoom or optical image stabilization. The SMA actuator wire (11) is coated with an electrically insulating layer (40) of thickness in the range from 0.3 μm to 10 μm. The layer (40) provides electrical insulation whilst permitting cooling that provides a rapid response time of the SMA actuator wire (11).