Negative Meniscus Lens Ghost Light Suppression
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Solution Overview
Problem
Super-wide-angle lenses often suffer from ghost light issues due to the reflection of light by negative meniscus lenses, which can result in image quality degradation and aberrations, particularly in ultra-wide-angle imaging applications like virtual reality.
Innovation Solution
The optical system design includes a first lens unit with negative refractive power and a meniscus shape convex to the object side, combined with an aperture stop and a second lens unit with positive refractive power, adhering to specific inequalities to minimize ghost light while maintaining an ultra-wide angle and high performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a negative meniscus lens with large curvature is disposed closest to the object in a super-wide-angle lens, then the angle of view can be expanded to approximately 180°, but ghost light is generated due to light reflection by the meniscus lens reaching the image plane
Solution Approach 1:
The patent extracts and removes the harmful reflective surfaces from the optical path. Specifically, it eliminates the object-side surface of the first lens and the image-side surface of the second lens from contributing to ghost light, thereby removing the harmful reflection paths while preserving the wide-angle capability
Solution Approach 2:
The patent converts the potentially harmful ghost light reflections into beneficial effects by designing the lens surfaces with specific curvatures that redirect reflected light away from the image plane. The object-side surface of the first lens and the image-side surface of the second lens are designed with curvatures that cause reflections to diverge or redirect to non-critical areas, transforming harmful reflections into useful light distribution
2Manufacturing precision
If the first lens has a meniscus shape convex to the object side, then off-axis aberrations can be corrected, but the distance from the first lens to the aperture stop must be precisely controlled to prevent ghost light
Solution Approach 1:
The patent employs specific parameter ranges for the distance dG1P between the first lens and the aperture stop, defined by the inequality 14.2 < dG1P/f × 100 < 34.5. This parameter control optimizes both aberration correction and ghost light suppression by positioning the aperture stop at a critical distance that blocks reflected light paths while maintaining proper optical performance
Solution Approach 2:
The patent uses asymmetric lens designs where the first lens has a meniscus shape convex to the object side with specific curvature relationships. The asymmetry in lens shapes and the non-symmetric positioning of the aperture stop relative to the lens elements enable effective aberration correction while creating geometric configurations that naturally block ghost light paths
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 effectively reduces ghost light and maintains high image quality by optimizing the placement and curvature of lens elements, ensuring that ghost light is less likely to reach the image plane, thereby correcting off-axis aberrations and distortion.
Implementation Method 1
a first lens unit having negative refractive power... The first lens has a meniscus shape that is convex to the object side
Implementation Method 2
an aperture stop... effectively reduces ghost light and maintains high image quality by optimizing the placement and curvature of lens elements, ensuring that ghost light is less likely to reach the image plane
Implementation Method 3
a second lens unit having positive refractive power
Data Source
AI summary
An optical system includes, in order from an object side to an image side, a first lens unit having negative refractive power, an aperture stop, and a second lens unit having positive refractive power. The first lens unit includes a first lens having negative refractive power disposed closest to an object. The first lens has a meniscus shape that is convex to the object side. A predetermined condition is satisfied.