Five-Lens Display Optics for High Magnification and Long Eye Relief
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Solution Overview
Problem
Existing display optical systems face challenges in achieving high magnification, long eye relief, and effective aberration correction while managing lens manufacturing complexity and cost, particularly due to the use of high refractive materials.
Innovation Solution
A display optical system comprising a sequence of single lenses with specific refractive powers and configurations, including a first lens with positive power, a second lens with negative power, a third lens with positive power, and a fifth lens with positive power, adhering to certain refractive index and focal length ratios, to optimize magnification, eye relief, and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high refractive materials are used for lenses to achieve high magnification, then magnification is improved, but cost increases
Solution Approach 1:
The patent changes the refractive index parameter of the lens material from high (expensive) to moderate (cost-effective), while compensating for magnification requirements through optimized lens configuration and focal length ratios. This allows achieving the same optical performance with lower-cost materials.
Solution Approach 2:
The patent applies different refractive indices to different lenses in the system (first lens: 1.504-1.600, second lens: 1.635-1.700, third lens: 1.504-1.600), optimizing each lens's contribution to magnification and aberration correction. This localized optimization achieves system-level high magnification without requiring all lenses to use expensive high-refractive materials.
2Power
If refracting power of each lens is increased for high magnification, then magnification is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent divides the total refracting power requirement into multiple lenses with moderate individual powers. Instead of using one or two high-power lenses that would be difficult to manufacture, the system uses five lenses with distributed refracting powers, making each lens easier to manufacture while achieving the same total magnification.
Solution Approach 2:
The patent optimizes the focal length ratios between lenses (e.g., 0.300 < f1/f2 < 1.500, 0.500 < f3/f4 < 2.000) to balance the refracting power distribution. This parameter optimization ensures that no single lens requires excessive refracting power, thereby reducing manufacturing difficulty while maintaining high system magnification.
3Power
If refracting power of each lens is increased for high magnification, then magnification is improved, but sensitivity becomes extremely large
Solution Approach 1:
The patent segments the magnification function across five lenses with moderate refracting powers. This segmentation reduces the sensitivity of each individual lens to manufacturing errors, as lower-power lenses are less sensitive to small deviations in curvature and thickness compared to high-power lenses.
Solution Approach 2:
The patent sets specific focal length ratios and refractive index ranges to optimize the distribution of refracting power. By controlling parameters such as 0.300 < f1/f2 < 1.500 and 1.635 < nd2 < 1.700, the system achieves high magnification with reduced sensitivity to manufacturing tolerances, as the power is distributed rather than concentrated in a few high-power elements.
4Power
If lens arrangement and refractive powers are optimized for high magnification, then magnification and eye relief are improved, but device complexity increases
Solution Approach 1:
The patent uses a five-lens segmented configuration that achieves high magnification and long eye relief through systematic arrangement. While more lenses increase component count, the segmented design allows for modular assembly and standardized mounting, which can reduce overall system integration complexity compared to fewer, more complex high-power lenses.
Solution Approach 2:
The patent optimizes specific parameter ranges (focal length ratios, refractive indices, lens spacing) to achieve high magnification with a manageable lens arrangement. By constraining parameters such as 0.400 < f2/f3 < 1.200 and positioning lenses at specific intervals, the system achieves high performance without excessive complexity in the overall optical path design.
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 high magnification, long eye relief, and improved optical performance with reduced lens size and manufacturing complexity, while effectively correcting spherical aberration, curvature of field, and astigmatism.
Implementation Method 1
a first lens having positive refractive power, a second lens having positive refractive power, a third lens having negative refractive power, a fourth lens having positive refractive power, and a fifth lens having positive refractive power
Data Source
AI summary
A display optical system configured to enable an image displayed on a display element to be observed includes, in order from a display element side to an observation side, a first lens having positive refractive power, a second lens having positive refractive power, a third lens having negative refractive power, a fourth lens having positive refractive power, and a fifth lens having positive refractive power. Each of the first lens, second lens, third lens, fourth lens, and fifth lens is a single lens that is not a cemented lens. A predetermined condition is satisfied.