Imaging System Focus Control via Thermal Expansion Compensation
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Solution Overview
Problem
Temperature changes in electronic devices' lens modules due to heat generation can cause the lens position to deviate from the optimal position, leading to out-of-focus images, as components like the lens barrel and lens contract or expand, affecting autofocus systems.
Innovation Solution
The implementation of a system that measures ambient temperature and computes a corrected target position for the lens module based on known thermal characteristics, such as the material, thermal time constant, and linear expansion coefficient of the lens barrel, to adjust the actuator and maintain optimal focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If autofocus systems adjust lens position to optimize image quality, then image sharpness is improved, but thermal expansion and contraction from temperature changes cause the lens position to deviate from optimal, resulting in out-of-focus images
Solution Approach 1:
The patent applies preliminary action by measuring the ambient temperature and computing a corrected target position in advance, before the thermal expansion or contraction actually occurs. The system uses known thermal characteristics (linear expansion coefficient, thermal time constant) to predict the lens position deviation and pre-adjusts the actuator position to compensate for the upcoming thermal effect, thereby maintaining accurate focus despite temperature fluctuations
Solution Approach 2:
The patent changes the actuator control parameter from a fixed target position to a dynamically corrected target position that accounts for temperature. By introducing temperature as a variable parameter and using it to adjust the target position calculation, the system adapts to thermal conditions and maintains focus accuracy across varying temperatures
2Adaptability or versatility
If the lens module operates in environments with temperature changes, then adaptability to different environments is improved, but thermal expansion and contraction cause lens position deviation, degrading image quality
Solution Approach 1:
The patent implements feedback by continuously measuring the ambient temperature and using this information to adjust the lens position. The system establishes a feedback loop where temperature measurements inform corrections to the target position, allowing the lens module to adapt to environmental changes while maintaining precise focus. This closed-loop approach enables the system to compensate for thermal effects in real-time
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 effectively predicts and compensates for thermal expansion, maintaining image quality by adjusting the lens position accurately, even with temperature fluctuations, thereby preventing out-of-focus issues.
Implementation Method 1
Changes in the ambient temperature may cause components, such as the lens barrel and the lens, to contract or expand
Data Source
AI summary
Various embodiments of the present technology may comprise methods and apparatus for focus control in an imaging system. The methods and apparatus may comprise various circuits and/or systems configured to measure the ambient temperature of the lens module and compute a corrected target position based on known thermal characteristics of the lens and/or the lens barrel. Factors used to obtain the corrected target position may comprise the material the of the lens barrel, the thermal time constant of the lens barrel, the linear expansion coefficient of the lens barrel, the effective focal length (EFL) of the lens, the thermal response of the lens, and/or the temperature characteristic coefficient of the EFL.