Intermediate-Imaging Optical System With Fixed Negative Lens Group
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Solution Overview
Problem
Wide-angle projection systems with intermediate imaging-based optical systems face issues of increased weight and thermal deformation, leading to optical aberrations and tilting, especially under high-intensity conditions.
Innovation Solution
An optical system with an intermediate imaging position, comprising a magnification optical system and a relay optical system with specific lens group configurations, where the negative lens group is fixed, and the two lens groups are displaced during zooming, to reduce moments on the center of gravity and mitigate thermal effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a lens made of synthetic resin is used to reduce weight, then the optical system becomes lightweight, but thermal deformation increases leading to optical aberrations
Solution Approach 1:
The patent uses composite lens structures combining synthetic resin and glass materials. Specifically, the optical system includes both resin lenses (for weight reduction) and glass lenses (for thermal stability), creating a composite optical system that balances weight and thermal performance requirements
Solution Approach 2:
The patent carefully selects and controls material parameters including the glass transition temperature of resin lenses (Tg ≥ 80°C), refractive indices, and Abbe numbers to ensure that resin lenses maintain dimensional stability under high-intensity light conditions while keeping the overall system lightweight
2Area of stationary object
If the optical system is designed for wide-angle projection with short focal length, then wide screen coverage is achieved, but the total length increases making the system heavier
Solution Approach 1:
The optical system is divided into multiple lens groups with specific functions: a first lens group with negative power, a second lens group with positive power, and additional groups. This segmentation allows each group to be optimized for specific purposes, achieving wide-angle coverage without proportionally increasing total weight
Solution Approach 2:
Different regions of the optical system use different materials and designs tailored to local requirements. For example, the first lens group uses specific resin materials with Tg ≥ 80°C positioned at the wide-angle end where weight reduction is most beneficial, while other critical areas use glass or different resin compositions
3Illumination intensity
If high-intensity light passes through the lens for high-intensity projection, then brightness is improved, but thermal deformation increases causing optical aberrations
Solution Approach 1:
The patent specifies that resin lenses have a glass transition temperature Tg ≥ 80°C, ensuring they maintain dimensional stability under high-intensity light conditions. This parameter control prevents thermal deformation that would cause optical aberrations during high-brightness projection
Solution Approach 2:
The optical system uses glass lenses as intermediary elements between the high-intensity light source and resin lenses. These glass lenses have superior thermal stability and help distribute and manage thermal loads, protecting the resin components from excessive temperature increases
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
Stabilizes optical performance under high-intensity light conditions by reducing the moment on the center of gravity and minimizing thermal deformation, maintaining stable optical performance.
Implementation Method 1
an optical system internally having an intermediate imaging position that is conjugated to a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side
Implementation Method 2
a relay optical system positioned on the reduction side with respect to the intermediate imaging position; the relay optical system including: a first lens group positioned closest to the magnification side; two lens groups positioned on the reduction side with respect to the first lens group; and a negative lens group interposed between the two lens groups
Data Source
AI summary
The present disclosure is directed to an optical system internally having an intermediate imaging position that is conjugated to a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side, respectively, the optical system comprising: a magnification optical system positioned on the magnification side with respect to the intermediate imaging position; and a relay optical system positioned on the reduction side with respect to the intermediate imaging position; the relay optical system including: a first lens group positioned closest to the magnification side; two lens groups positioned on the reduction side with respect to the first lens group; and a negative lens group interposed between the two lens groups, wherein during zooming the negative lens is fixed, while the two lens groups are displaced.