Polarized Optical Layout for Compact Aberration-Corrected Imaging
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Solution Overview
Problem
Existing optical systems for display devices face challenges in achieving miniaturization and improving light quantity efficiency while effectively correcting aberrations such as spherical aberration, comatic aberration, astigmatism, and field curvature, due to limitations in aberration correction and light transmission efficiency.
Innovation Solution
An optical system configuration comprising a first reflective polarizing plate, a first lens with positive refractive power, a half mirror, a second lens with positive refractive power, and a second reflective polarizing plate, with quarter wave plates positioned to enhance light efficiency and correct aberrations, utilizing symmetrical element groups and specific conditional expressions for lens parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the optical system uses conventional designs with limited space accommodation, then miniaturization is difficult to achieve, but the system size remains large
Solution Approach 1:
The patent applies asymmetry by making the second lens have a convex surface on the pupil surface side rather than a symmetric biconvex shape. This asymmetric design allows the lens to simultaneously correct spherical aberration and comatic aberration more effectively within the limited space, resolving the contradiction between miniaturization and aberration correction capability.
Solution Approach 2:
The patent employs parameter changes by optimizing the refractive indices and Abbe numbers of the lenses within specific ranges (1.45<Nd1<1.70, 20<vd1<60 for the first lens; 1.40<Nd2<1.70, 20<vd2<60 for the second lens). These parameter optimizations enable effective aberration correction while maintaining a compact optical system structure.
2Reliability
If the optical system accommodates more correction elements, then aberration correction improves, but light quantity efficiency decreases
Solution Approach 1:
The patent extracts and eliminates unnecessary optical elements from the conventional design. By using only two lenses with specific asymmetric configurations and refractive power distributions, the system achieves effective aberration correction without the light losses associated with additional semi-transmissive surfaces or complex multi-element arrangements.
Solution Approach 2:
The patent replaces complex mechanical optical systems with a simplified two-lens configuration. Instead of using multiple semi-transmissive surfaces and refractive elements as in conventional designs, the invention uses purely refractive optics with optimized parameters to achieve both aberration correction and high light quantity efficiency.
3Reliability
If the optical system uses multiple semi-transmissive surfaces for correction, then aberration control improves, but light transmission efficiency decreases
Solution Approach 1:
The patent replaces semi-transmissive surface-based correction mechanisms with pure refractive lens systems. The two lenses with specific power distributions and asymmetric surfaces provide aberration control through refraction alone, eliminating the need for semi-transmissive surfaces that would reduce light transmission efficiency.
Solution Approach 2:
The patent optimizes the refractive parameters (refractive index and Abbe number) of the lenses within specific ranges to achieve effective aberration control. By carefully selecting these parameters, the system achieves precise aberration correction while maintaining high light transmission efficiency without requiring multiple semi-transmissive surfaces.
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-resolution imaging with improved light quantity efficiency and reduced power consumption by effectively correcting aberrations, while maintaining a compact size.
Implementation Method 1
The reflective polarizing plate reflects linearly polarized light having a specific polarization direction and allows linearly polarized light having a polarization direction orthogonal thereto to pass through.
Implementation Method 2
The quarter wave plate converts linearly polarized light into circularly polarized light and converts circularly polarized light into linearly polarized light by delaying the phase of polarized light by 1/4λ.
Implementation Method 3
The half mirror allows 50% of the light rays to pass through and reflects the remaining 50% of the light rays.
Implementation Method 4
Having a positive refractive power, the first lens restrains spherical aberration, astigmatism, field curvature, and distortion. Having a positive refractive power, the second lens well corrects spherical aberration, comatic aberration, astigmatism, field curvature, and distortion.
Data Source
AI summary
An optical system includes, in order from a pupil surface side to a display surface side, a first reflective polarizing plate, a first lens having a positive refractive power, a half mirror, a second lens having a positive refractive power, and a second reflective polarizing plate. The optical system further includes a first quarter wave plate arranged between a pupil surface and the half mirror, and a second quarter wave plate arranged between the half mirror and a display surface. The second lens has a paraxially convex surface on the pupil surface side. Further, in the case where a paraxial curvature radius of a surface of the first lens on the pupil surface side is r1 and a paraxial curvature radius of a surface of the first lens on the display surface side is r2, the optical system satisfies a conditional expression below: −3.2<r1/r2<−0.9.