Lens Unit Temperature Compensation via Differential Thermal Expansion
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Solution Overview
Problem
Existing imaging devices face challenges in maintaining focus performance due to temperature changes, as the focal length of the lens changes with temperature, causing the focus to deviate from the imaging surface, leading to reduced image quality.
Innovation Solution
A lens unit with a temperature compensation member that connects the lens frame and barrel, allowing the lens frame to move parallel to the optical axis, ensuring the focus remains on the imaging surface by adjusting the lengths of the temperature compensation member and lens barrel in response to temperature changes, thereby maintaining the focal length equation and reducing focus deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the lens and imaging element are fixed relative to each other, then the structure is simple, but the focus deviates from the imaging surface when temperature changes
Solution Approach 1:
The lens frame is designed to be movable relative to the lens barrel along the optical axis through a releasing mechanism. When temperature changes cause focal length variation, the lens frame can dynamically adjust its position to maintain focus on the imaging surface, transforming the static fixed structure into a dynamic adjustable one.
Solution Approach 2:
The releasing mechanism changes the positional parameter of the lens frame relative to the lens barrel based on temperature-induced focal length changes. By allowing the lens frame to move to different positions, the system adapts to temperature variations and maintains optimal focus performance.
2Reliability
If the lens frame is made movable to compensate for temperature changes, then focus performance is maintained, but the device complexity increases
Solution Approach 1:
A releasing mechanism is introduced as an intermediary component between the lens frame and the lens barrel. This mechanism enables the lens frame to move relative to the lens barrel while maintaining a controlled connection, serving as a mediator that allows necessary movement without requiring a completely separate or complex adjustment system.
Solution Approach 2:
The lens frame's movement is driven by the temperature-induced focal length changes themselves. The system uses the physical phenomenon (focal length change with temperature) as the driving force for the adjustment, rather than requiring an external actuator or complex control system, thus achieving self-service temperature compensation.
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 stabilizes focus performance across varying temperatures by controlling component lengths, ensuring the focus remains on the imaging surface or within a predetermined distance, thus minimizing the impact of temperature fluctuations on image quality.
Implementation Method 1
A length of extension in the direction parallel to the optical axis per unit temperature of a part of the temperature compensation member from the first portion to the second portion differs from a length of extension in the direction parallel to the optical axis per unit temperature of a part of the lens barrel
Data Source
AI summary
A lens unit includes a lens, a frame, a barrel housing the frame therein and is connectable to a substrate for mounting an imaging element, and a temperature compensation member including first and second portions apart from each other in an optical-axis parallel direction. The temperature compensation member is in contact with the barrel at the first portion and with the frame at the second portion. The frame is movable in the optical-axis parallel direction with respect to the barrel. The length of extension in the optical-axis parallel direction per unit temperature of a part of the temperature compensation member between the first and second portions differs from the length of extension in the optical-axis parallel direction per unit temperature of a part of the barrel closer to a barrel side connected to the substrate than a part of the barrel in contact with the first portion.