Soft Focus Optical System Using Negative-Positive Lens Pair
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Solution Overview
Problem
Current soft focus lens technologies require separate design and manufacturing procedures for different photography uses, leading to increased costs and reduced lens performance due to the need for aspherical surfaces, which are difficult to manufacture and increase axial deviation sensitivity.
Innovation Solution
A soft focus optical system consisting of a negative lens and a positive lens, with specific focal length and refractive power ratios, that can be integrated with or attached to an image pickup optical system to provide a soft focus effect while maintaining sharp focus capabilities, using conditional expressions to optimize lens configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft focus lens is designed using separate design procedures and aspherical surfaces, then soft focus effect is achieved, but manufacturing cost increases and manufacturing precision becomes more difficult
Solution Approach 1:
The patent merges the soft focus function with the normal focus lens by integrating a soft focus lens unit into the existing lens structure. The soft focus lens unit includes a negative lens and a positive lens with specific focal length relationships, allowing the same lens to provide both normal focus and soft focus effects without requiring completely separate design procedures or complex aspherical surfaces.
Solution Approach 2:
The lens system is designed to be multi-functional, where the image pickup optical system can operate in both normal focus mode and soft focus mode. The soft focus lens unit is configured with movable components that allow switching between different focus modes, enabling a single lens to serve multiple purposes and reducing the need for separate specialized lenses.
2Reliability
If aspherical surfaces are added to realize soft focus lens, then soft focus effect is achieved, but axial deviation sensitivity increases and assembling difficulty increases
Solution Approach 1:
The patent combines the soft focus lens unit with the image pickup optical system in such a way that the soft focus function is achieved through the interaction of standard spherical surfaces rather than requiring precise aspherical surfaces. The negative lens and positive lens in the soft focus lens unit work together to produce the soft focus effect while maintaining tolerance to axial deviations.
3Reliability
If separate design procedures are used for different photography uses, then specific lens performance is optimized, but the number of lenses increases and cost increases
Solution Approach 1:
The patent creates a universal lens system that can perform both normal photography and soft focus photography using the same image pickup optical system. The soft focus lens unit is designed to be integrated with the existing lens, allowing a single lens assembly to serve multiple photographic purposes and reducing the need for multiple specialized lenses.
Solution Approach 2:
The lens system incorporates movable components that allow dynamic switching between normal focus mode and soft focus mode. The soft focus lens unit can be moved along the optical axis to adjust the focus state, enabling the same physical lens to adapt to different photographic requirements without requiring separate fixed lenses for each mode.
4Reliability
If a soft focus filter is used with random small openings, then soft focus effect is achieved, but spherical aberration control becomes difficult
Solution Approach 1:
The patent merges the soft focus function with refractive optics by integrating a soft focus lens unit composed of a negative lens and a positive lens. This approach replaces the diffractive soft focus filter with random openings with a refractive optical system that provides controlled spherical aberration through precisely designed lens curvatures and focal lengths, achieving both soft focus effect and aberration control.
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 proposed solution allows for a cost-effective and efficient production of soft focus lenses with reduced aberrations and axial deviation, enabling both sharp and soft focus effects without significant changes to the focal length of the image pickup optical system, thus improving lens performance and usability.
Implementation Method 1
A soft focus optical system consisting of a negative lens and a positive lens, with specific focal length and refractive power ratios
Data Source
AI summary
Provided is a soft focus optical system configured to be arranged on an image side of an image pickup optical system, the soft focus optical system consisting of a negative lens and a positive lens, in which a conditional expression 0.950<B<1.050 is satisfied, where B is a magnification of the soft focus optical system, and in which a conditional expression, |(2Y)2/(fn×fp)|≤0.005 is satisfied or conditional expressions, 0.005<|(2Y)2/(fn×fp)|; and fn/fp<−0.750 are satisfied, where fn is a focal length of the negative lens, fp is a focal length of the positive lens, and Y is a maximum image height of the image pickup lens.