Floating Focus Lens Layout for Compact Aberration-Stable Imaging
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Solution Overview
Problem
Existing optical systems struggle to achieve high optical performance and compact size while minimizing aberration changes during focusing, particularly in image pickup systems.
Innovation Solution
The optical system employs a floating method with multiple lens units, including a first lens unit with positive refractive power, a middle group with at least two lens units, and a final lens unit with negative refractive power, adhering to specific conditional expressions to optimize focal lengths and refractive powers, thereby reducing aberrations and system size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the final lens unit has low refractive power, then the optical system can be designed with a floating method to reduce aberration changes during focusing, but it becomes difficult to achieve high optical performance and to downsize the optical system
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive power of the final lens unit to have absolute value greater than 0.5 times the focal length of the optical system. This parameter optimization enables the final lens unit to effectively correct aberrations while maintaining a compact system size, resolving the contradiction between optical performance and system size.
Solution Approach 2:
The patent employs a floating method where the second focus lens unit moves independently during focusing operations. This dynamic adjustment of lens unit positions allows the system to maintain high optical performance across different object distances while keeping the overall system compact through coordinated movement of multiple lens units.
2Reliability
If multiple lens units are moved independently during focusing, then changes in aberration can be reduced, but the device complexity increases
Solution Approach 1:
The patent divides the focusing function into multiple independent lens units (first focus lens unit and second focus lens unit), where each unit can move independently to correct different types of aberrations. This segmentation allows sophisticated aberration control while maintaining relatively simple individual unit structures, managing the complexity through functional division.
Solution Approach 2:
The patent implements dynamic focusing by enabling independent movement of the second focus lens unit relative to other lens units. This dynamic configuration allows the system to adapt lens positions during focusing to minimize aberration changes, achieving high optical performance through controlled dynamic adjustments rather than static design.
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 configuration achieves high optical performance and compact size over various object distances by effectively managing aberrations and facilitating high-speed focusing.
Implementation Method 1
an optical system includes a first lens unit having positive refractive power, a middle group including at least two lens units, and a final lens unit having negative refractive power
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The optical system according to the present invention consists of a first lens unit with positive refractive power disposed closest to an object side, a middle group including at least two lens units, and a final lens unit with negative refractive power disposed closest to an image side in which intervals between adjacent lens units are changed during focusing. The middle group includes a first focus lens unit configured to move during focusing, and a second focus lens unit disposed on the image side of the first focus lens unit and configured to move during focusing. An aperture stop is disposed between two lenses included in the middle group. Here, a focal length of the optical system, a focal length of the final lens unit, and a focal length of a second focus lens unit are appropriately determined.