Folded Polarization Optical Layout for Compact Wide-Angle Imaging
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Solution Overview
Problem
Existing optical systems for image pickup apparatuses face challenges in achieving reduced size and high optical performance, particularly in systems with periscope and catadioptric designs, due to issues such as increased chromatic aberration, reduced image circle, and optical crosstalk, which hinder wide-angle imaging and high image quality.
Innovation Solution
An optical system utilizing a first and second transmissive reflective surface with a quarter waveplate, configured to satisfy specific inequalities that balance refractive and reflective powers, and employ polarization selective elements to manage light path and reduce ghost light, ensuring high image quality and compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a periscope optical system or catadioptric optical system is used to reduce overall optical length, then the size is reduced, but chromatic aberration increases and image quality deteriorates
Solution Approach 1:
The patent changes the refractive index parameter by introducing a lens with a specific refractive index range (1.60 < nd < 2.00) to control chromatic aberration. This parameter change allows the system to maintain compact size while improving optical performance by balancing the refractive powers of different elements.
Solution Approach 2:
The patent employs a composite optical system combining multiple lens elements with different refractive indices and optical properties. By compositeing lenses with specific refractive index ranges and incorporating transmissive reflective surfaces, the system achieves both compact size and reduced chromatic aberration through the synergistic effects of different optical materials.
2Volume of moving object
If transmissive reflective surfaces are used to fold the optical path, then the system size is reduced, but optical crosstalk and ghost light increase
Solution Approach 1:
The patent converts the harmful effect of ghost light and optical crosstalk into a beneficial control mechanism by carefully designing the refractive powers and orientations of transmissive reflective surfaces. The system uses the reflected light paths to achieve compact folding while controlling crosstalk through specific refractive power relationships (|Φm1| < 0.5 and |Φm2| < 0.5).
Solution Approach 2:
The patent controls optical crosstalk by changing the refractive power parameters of transmissive reflective surfaces to specific ranges. By setting |Φm1| < 0.5 and |Φm2| < 0.5, the system minimizes unwanted reflections and ghost images while maintaining the compact folded optical path structure.
3Reliability
If multiple lenses are used to correct aberrations, then image quality is improved, but the system becomes more complex and larger
Solution Approach 1:
The patent makes each lens element perform multiple functions: correcting chromatic aberration, controlling spherical aberration, and managing optical path folding. By designing lenses with refractive indices in specific ranges (1.60 < nd < 2.00 for certain elements), each component serves universal purposes, reducing the total number of elements needed while maintaining high image quality.
Solution Approach 2:
The patent merges the functions of multiple optical elements into fewer components. By combining refractive lens elements with transmissive reflective surfaces and using lenses that simultaneously correct multiple aberration types, the system achieves high image quality with reduced complexity compared to traditional multi-element designs.
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 reduced size and improved optical performance by minimizing chromatic aberration and crosstalk, supporting wide-angle imaging with high image quality and efficient light management.
Implementation Method 1
a first transmissive reflective surface, a quarter waveplate, and a second transmissive reflective surface disposed in this order from the object side to the image side
Implementation Method 2
AΦr/AΦm does not exceed a predetermined maximum value, where AΦr is an average of absolute values of refractive powers of lenses included in the optical system, and AΦm is an average of absolute values of refractive powers of the first transmissive reflective surface and the second transmissive reflective surface
Data Source
AI summary
An optical system includes, in order from an object side to an image side, a first transmissive reflective surface, a polarizing element, and a second transmissive reflective surface. The optical system is a primary imaging system. Light from the object side transmits through the first transmissive reflective surface and the polarizing element in this order, is reflected by the second transmissive reflective surface toward the object side, transmits through the polarizing element, is reflected by the first transmissive reflective surface toward the image side, transmits through the polarizing element and the second transmissive reflective surface in this order, and travels toward the image side. A predetermined inequality is satisfied.