Folded Optical Layout for Bright Compact Image Pickup
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Solution Overview
Problem
Existing optical systems face challenges in achieving a compact size, high brightness, and effective aberration correction, particularly with folded optical systems using transmissive reflective surfaces.
Innovation Solution
An optical system configuration comprising a first lens, a first and second waveplate, and a first and third transmissive reflective surface, arranged in a specific order, with inequalities defining the distances and refractive indices to ensure identical focal lengths and back focus, allowing light to be imaged via two optical paths, enhancing transmittance and reducing system size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a folded optical system using transmissive reflective surfaces is used, then the system size is reduced, but the transmittance decreases and brightness is reduced
Solution Approach 1:
The optical system is divided into multiple reflective surfaces (first, second, and third transmissive reflective surfaces) that split the light into two separate optical paths. This segmentation allows the system to maintain compact folded geometry while compensating for transmittance losses through dual-path light gathering
Solution Approach 2:
Two separate optical paths are merged to image light onto the same image plane. By combining the light from both paths, the system effectively doubles the transmittance compared to a single-path folded system, thereby improving brightness while maintaining the compact folded structure
2Volume of moving object
If multiple transmissive reflective surfaces are used to reduce system size, then the number of components increases, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
Each transmissive reflective surface is designed with specific local optical properties (convex or concave curvature) to correct particular types of aberrations. The first and third surfaces are configured as convex toward the object side, while the second surface is concave, creating localized correction zones for different aberration types throughout the optical path
Solution Approach 2:
The optical system satisfies specific parameter relationships (inequalities involving focal lengths, back focus distances, and surface curvatures) to ensure that the combined effect of multiple reflective surfaces produces identical focal lengths and back focus for both optical paths, thereby maintaining manufacturing precision and aberration correction
3Illumination intensity
If two optical paths are used to double transmittance, then the device complexity increases, but the F-number becomes brighter
Solution Approach 1:
The multiple transmissive reflective surfaces serve dual functions: they guide light through folded paths to reduce system size while simultaneously acting as aberration correction elements. This multi-functionality allows the system to achieve bright imaging without proportionally increasing complexity
Solution Approach 2:
The optical system employs asymmetric configuration of reflective surfaces (convex first surface, concave second surface, convex third surface) to create two distinct optical paths with different geometries. This asymmetry enables effective aberration correction while maintaining a relatively simple overall structure that achieves bright imaging performance
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 solution achieves a bright F-number and reduced size while maintaining high optical performance by doubling the transmittance and correcting aberrations, such as curvature of field and chromatic aberration.
Implementation Method 1
a first transmissive reflective surface, a second transmissive reflective surface, and a third transmissive reflective surface arranged in this order from an object side to an image side
Implementation Method 2
a first waveplate, a second waveplate
Data Source
AI summary
An optical system includes a first lens disposed closest to an object, a first transmissive reflective surface, a first waveplate, a second transmissive reflective surface, a second waveplate, and a third transmissive reflective surface arranged in this order from an object side to an image side, and an aperture stop. A predetermined inequality is satisfied.