Imaging Optical System Lens Group Movement Field Curvature Correction
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Solution Overview
Problem
Existing imaging optical systems face challenges in achieving excellent focusing performance and correcting field curvature and distortion, particularly during zooming and focusing actions, which affects image quality and manufacturing complexity.
Innovation Solution
The imaging optical system comprises multiple lens groups, including a field curvature correction lens group and a focusing lens group that move along the optical axis, with specific conditions (e.g., conditions (1) to (11) ensuring optimal lens placement and movement to maintain image quality and reduce effective diameters, thereby improving focusing performance and correcting field curvature and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple lens groups are used to achieve excellent focusing performance and correct field curvature, then imaging performance is improved, but device complexity increases
Solution Approach 1:
The lens system is divided into multiple lens groups (first lens group with positive power, second lens group with negative power, third lens group with positive power, and fourth lens group with positive power), each with specific functions. This segmentation allows independent optimization of each group's movement and power, enabling excellent focusing performance and field curvature correction while managing overall system complexity through modular design.
Solution Approach 2:
The patent implements dynamic movement of specific lens groups during focusing and zooming operations. The second lens group moves along the optical axis during focusing action, and the third lens group moves during zooming action. This dynamic adjustment allows the system to maintain excellent imaging performance across different focusing states and zoom positions without requiring a completely complex reconfiguration of the entire lens system.
2Reliability
If lens groups move during zooming and focusing actions, then focusing performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for lens group movements and power ratios to optimize performance while managing manufacturing precision requirements. Condition (1) specifies the power ratio between the second and first lens groups, and condition (2) specifies the power ratio between the third and fourth lens groups. These parameter constraints allow the system to achieve excellent focusing performance with manageable manufacturing precision by optimizing the relationship between moving and stationary components.
3Manufacturing precision
If field curvature correction lens group moves along optical axis, then field curvature is corrected, but device complexity increases
Solution Approach 1:
The third lens group with positive power serves multiple functions: it corrects field curvature through its specific power ratio (condition (2)), participates in zooming action by moving along the optical axis, and contributes to overall image formation. This multi-functionality reduces device complexity by combining field curvature correction and zooming capabilities in a single lens group rather than requiring separate mechanisms.
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 system achieves excellent imaging performance by ensuring precise lens group movements and placements, maintaining image quality across zooming and focusing actions while reducing manufacturing complexities and aberrations.
Implementation Method 1
The imaging optical system includes a first lens group located at a furthest place on the magnification side and a rear group in this order from the magnification side toward the reduction side. The first lens group includes a field curvature correction lens group moving along an optical axis when an amount of a field curvature is changed, and a focusing lens group moving along the optical axis during a focusing action from an infinity focus state to a proximate focus state.
Data Source
AI summary
An imaging optical system includes a plurality of lens groups each moving such that spaces between each one of the plurality of lens groups change during a zooming. The imaging optical system conjugates a conjugate point on a magnification side and an intermediate imaging position, and conjugates a conjugate point on a reduction side and the intermediate imaging position. The imaging optical system includes a first lens group located at a furthest place on the magnification side and a rear group in this order from the magnification side toward the reduction side. The first lens group includes a field curvature correction lens group moving along an optical axis when an amount of a field curvature is changed, and a focusing lens group. The imaging optical system satisfies condition (4) below:|{(1−βcw2)×βcrw2}/{(1−βfw2)×βfrw2}|<0.2 (4)