Compact Optical System Air Space Design for Ghost Image Reduction
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Solution Overview
Problem
Existing optical systems face challenges in miniaturization and performance enhancement, leading to undesirable light interference due to increased lens density and reduced distances between lenses, which affects image quality.
Innovation Solution
An optical system design comprising a first lens unit with negative lenses, a second unit with positive refractive power, and a third unit with negative refractive power, optimized by specific air space lengths and focal lengths to minimize undesirable light and aberrations, while maintaining high optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of lenses is increased to enhance optical performance, then image quality is improved, but the overall length of the optical system increases and miniaturization is hindered
Solution Approach 1:
The patent applies parameter changes by optimizing the air space distances between lens units and adjusting the focal lengths of individual lenses. Specifically, the air space between the first and second lens units is set to 0.08x1/TTL ≤ d ≤ 0.35, and between the second and third lens units 0.08x2/TTL ≤ d ≤ 0.25, allowing compact arrangement while maintaining optical performance
Solution Approach 2:
The patent employs a nested arrangement where multiple lens units with different refractive powers are compactly positioned along the optical axis. The first lens unit (negative power), second lens unit (positive power), and third lens unit (negative power) are nested in sequence, maximizing space utilization and achieving miniaturization
2Length of moving object
If the distance between lenses is decreased to miniaturize the optical system, then the overall length is reduced, but undesirable reflected light reaches the imaging plane more easily
Solution Approach 1:
The patent introduces air spaces as intermediary regions between lens units. These air spaces act as optical separators that disrupt the direct path of reflected light from reaching the imaging plane, while still allowing the compact arrangement necessary for miniaturization
Solution Approach 2:
The patent converts the potentially harmful reflected light into a beneficial design constraint. By strategically positioning air spaces and lens surfaces, the reflected light that would normally cause ghosts is redirected or blocked, and this constraint is used to optimize the overall optical path and reduce other types of aberrations
3Length of moving object
If lens surfaces are positioned closer together to reduce optical system length, then miniaturization is achieved, but ghost images and light interference increase
Solution Approach 1:
The patent segments the optical system into distinct lens units separated by air spaces. This segmentation divides the continuous optical path into discrete sections, allowing control over light reflection at each interface and preventing ghost images from forming across the entire system
Solution Approach 2:
The patent addresses the two-dimensional constraint of lens spacing by introducing the third dimension of air space volume and optical path geometry. By controlling the three-dimensional arrangement of lens surfaces and air spaces, the system manages light reflection in multiple spatial dimensions, preventing ghost images while maintaining compact size
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 design effectively reduces undesirable light and aberrations, enabling a compact optical system with high performance and wide-angle capabilities, suitable for various image capturing applications.
Implementation Method 1
a first lens unit consisting of one or more negative lenses
Implementation Method 2
a second lens unit with positive refractive power
Implementation Method 3
a third lens unit consisting of a lens element with negative refractive power
Implementation Method 4
both having air spaces, the first air space being a widest air space of air spaces formed closer to the object side than a positive lens disposed closest to the object side in the optical system
Data Source
AI summary
An optical system includes, in order from an object side to an image side, a first lens unit consisting of one or more negative lenses, a second lens unit with positive refractive power disposed so as to have a first air space from the first lens unit, and a third lens unit disposed so as to have a second air space from the second lens unit. The first air space is a widest air space of air spaces formed closer to the object side than a positive lens disposed closest to the object side in the optical system. A surface of the first lens unit closest to the image side is concave. The third lens unit consists of a lens element with negative refractive power and having a concave surface on the object side. The optical system satisfies predetermined inequalities.