Imaging Optical System Differential Lens Movement Aberration Control
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Solution Overview
Problem
Existing imaging optical systems face challenges in achieving high image quality, wide angle, and large caliber with an F number below 2.1 while maintaining a small size, especially for short-distance objects, and require strong focusing forces, leading to image degradation and field tilt issues.
Innovation Solution
The proposed imaging optical system includes a first lens group, an aperture stop, and a second lens group with positive power, where the second lens group is moved differently during focusing from infinity to short-distance objects, with the first lens group and aperture stop remaining fixed, to reduce spherical aberration, coma aberration, and field tilt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the aperture stop is moved during focusing, then focusing capability is improved, but device complexity increases and reliability decreases
Solution Approach 1:
The patent extracts the focusing function from the aperture stop and assigns it to a dedicated focusing lens group. The aperture stop remains fixed while the focusing lens group moves independently to achieve focusing, thereby simplifying the system and improving reliability while maintaining focusing capability.
Solution Approach 2:
The patent divides the optical system into functionally independent segments: a fixed aperture stop for controlling light quantity and a separate movable focusing lens group for focusing. This segmentation allows each component to perform its specific function optimally without interfering with the other, resolving the contradiction between focusing capability and system stability.
2Ease of operation
If three lens groups including fixed and focusing lens groups are disposed in image side, then focusing is achieved, but F number becomes 2.1 or more (caliber is too large)
Solution Approach 1:
The patent optimizes the optical parameters by carefully designing the focal lengths, movement distances, and positions of the lens groups. By adjusting these parameters, the system achieves an F number below 2.1 while maintaining effective focusing capability, thus resolving the contradiction between focusing function and illumination intensity.
3Ease of operation
If strong focusing force is applied, then focusing from infinity to short-distance is improved, but spherical aberration and coma aberration increase
Solution Approach 1:
The patent implements a dynamic focusing mechanism where the focusing lens group moves along the optical axis with precisely controlled movement distance. The movement amount is optimized to be different for different lens groups, enabling effective focusing across the range from infinity to short-distance objects while minimizing the generation of spherical and coma aberrations.
Solution Approach 2:
The patent assigns different movement characteristics to different lens groups. The first lens group moves a different distance than the second lens group during focusing, allowing each group to contribute optimally to the focusing process while controlling aberrations. This localized differentiation in movement quality resolves the contradiction between focusing range and aberration control.
4Area of stationary object
If wide angle of field exceeding 38 degrees is achieved, then field of view is improved, but field tilt increases
Solution Approach 1:
The patent employs dynamic adjustment of lens group positions during focusing to compensate for field tilt. By coordinating the movement of multiple lens groups with different movement amounts, the system maintains a wide angle of field exceeding 38 degrees while minimizing field tilt across the image plane.
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 image quality, a wide angle of field exceeding 38 degrees, and a large caliber with an F number of 2.1 or less, while minimizing the need for strong focusing forces and reducing aberrations, thus enhancing the performance of camera apparatuses and personal digital assistants.
Implementation Method 1
the second front lens group and the second rear lens group are moved with a mutually different movement amount
Implementation Method 2
the second front lens group and the second rear lens group are moved with a mutually different movement amount
Implementation Method 3
When focusing from an infinity-distance object to a short-distance object, the first lens group and the aperture stop are fixed, and the second front lens group and the second rear lens group are moved with a mutually different movement amount
Data Source
AI summary
An imaging optical system, including a first lens group; an aperture stop; a second lens group having a positive power, the first lens group, the aperture stop and the second lens group being arranged from a side of an object sequentially, wherein the second lens group includes a second front lens group having a positive power and a second rear lens group having a positive power, the second front lens group and the second rear lens group being arranged sequentially from the object side, wherein, when focusing from an infinity-distance object to a short-distance object, the first lens group and the aperture stop are fixed, and the second front lens group and the second rear lens group are moved with a mutually different movement amount.