Zoom Lens Focus Range Control Using Auxiliary Lens Position
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Solution Overview
Problem
Thermal expansion and contraction of lens barrel components in imaging apparatuses cause individual variations in focus position and driving range, affecting focus operability and accuracy, especially in high-resolution imaging systems like 4K video cameras, where downsizing demands increased position sensitivity.
Innovation Solution
A focus driving range is set based on the position of an auxiliary lens, using a microprocessor to adjust the focus lens's driving range based on the auxiliary lens's position, incorporating temperature compensation and individual variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the lens barrel is downsized to increase position sensitivity for high-resolution imaging, then imaging resolution is improved, but thermal expansion and contraction cause larger individual variations in focus position and driving range
Solution Approach 1:
The patent applies parameter changes by detecting the actual position of the auxiliary lens (which shifts due to thermal expansion) and using this information to dynamically adjust the focus driving range parameters. The microprocessor modifies the focus driving instructions based on the detected auxiliary lens position, thereby compensating for thermal effects and maintaining reliable focus operation despite the downsized lens barrel structure.
2Measurement precision
If temperature detection sensors are mounted in the main body for correction, then focus position accuracy is improved, but the correction does not account for individual variations in thermal expansion
Solution Approach 1:
The patent implements feedback by detecting the actual position of the auxiliary lens (which varies individually due to thermal expansion characteristics) and using this detected information to adjust the focus driving range. This closed-loop feedback mechanism accounts for individual variations in thermal expansion by basing corrections on actual measured positions rather than generic temperature data, thereby improving both accuracy and adaptability.
3Device complexity
If the focus lens driving range is fixed, then device complexity is reduced, but focus operability deteriorates under thermal expansion and contraction
Solution Approach 1:
The patent applies dynamics by making the focus driving range adjustable rather than fixed. The microprocessor dynamically modifies the focus driving instructions based on the detected auxiliary lens position, allowing the system to adapt to thermal expansion conditions. This dynamic adjustment maintains excellent focus operability across temperature variations while adding minimal complexity, as the adjustment is automatically computed and applied without user intervention.
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
Ensures excellent focus operability and accuracy by mitigating the impact of thermal expansion and contraction on focus position and driving range, maintaining consistent focus performance across different temperature conditions.
Implementation Method 1
a position detector configured to detect a position of the second magnification varying lens
Implementation Method 2
the structural members of the lens barrel can mechanically expand and contract due to thermal expansion. This expansion and contraction can change the positional relationships between the lenses
Data Source
AI summary
An apparatus for an optical system including a first magnification varying lens configured to move with zooming, a second magnification varying lens of which a position is controlled based on a position of the first magnification varying lens, and a focus lens configured to adjust an in-focus position includes a detector configured to detect the position of the second magnification varying lens, and at least one processor and a memory coupled to the processor storing instructions that, when executed by the processor, cause the processor to function as a setting unit configured to set a driving range of the focus lens based on the position of the second magnification varying lens.