Folded Optical Assembly for Compact Telephoto Image Capture
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Solution Overview
Problem
Conventional optical systems struggle to balance high image quality, low sensitivity, proper aperture size, miniaturization, and field of view, especially in compact electronic devices with telephoto functions, due to thickness limitations and the inability to meet stringent optical zoom requirements.
Innovation Solution
A folded optical system with an optical folding assembly and multiple lens elements, featuring reflective and transmissive surfaces that redirect the optical path multiple times, allowing for a compact design while maintaining image quality, using prisms and aspheric lens elements to optimize space and refractive power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional telephoto lens is used to meet optical zoom requirements, then the optical zoom magnification is improved, but the total length becomes overly long and the aperture becomes overly small
Solution Approach 1:
The patent introduces a folded optical axis configuration that transitions from a linear optical path to a multi-dimensional folded path. The optical axis is divided into multiple segments (first optical axis, second optical axis, third optical axis, fourth optical axis) that are redirected through reflective surfaces, allowing the optical system to achieve telephoto functionality within a compact form factor by utilizing spatial folding rather than linear extension.
Solution Approach 2:
The patent employs reflective surfaces (first reflective surface, second reflective surface, third reflective surface) as intermediary elements to redirect the optical path. These reflective surfaces act as mediators that enable the optical system to achieve the required optical zoom magnification while maintaining a compact total length by changing the direction of light propagation rather than extending the optical path linearly.
2Length of moving object
If the lens barrel is cut to remove unused parts for miniaturization, then the device thickness is reduced, but the optical quality and sensitivity are compromised
Solution Approach 1:
Instead of simply cutting the lens barrel to reduce thickness, the patent employs a folded optical axis configuration that redirects light through multiple reflective surfaces. This allows the optical system to maintain sufficient optical path length and quality while achieving compact device thickness through spatial folding of the optical path.
Solution Approach 2:
The reflective surfaces serve as intermediary elements that enable the optical system to achieve both miniaturization and maintained optical quality. By introducing these intermediaries, the system can redirect the optical path to maintain proper optical track length while reducing the overall device thickness.
3Length of moving object
If a reflective element is added to achieve size reduction for telephoto function, then the device is miniaturized, but the optical path becomes complex and sensitivity decreases
Solution Approach 1:
The patent uses a folded optical axis configuration that redirects the optical path through multiple reflective surfaces, enabling the system to achieve telephoto functionality with a compact device size. The optical path is divided into multiple segments along different axes, allowing the system to maintain optical sensitivity while achieving miniaturization through spatial folding.
4Length of moving object
If the aperture size is reduced for miniaturization, then the device is compacted, but the light gathering ability and image quality are compromised
Solution Approach 1:
The patent employs a folded optical axis configuration that allows the optical system to maintain a compact aperture size while achieving sufficient light gathering ability through the folded optical path. The multiple reflective surfaces redirect light to maintain proper illumination intensity despite the reduced physical aperture size.
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 balanced optical system that is compact, maintains high image quality, and supports telephoto functions by effectively redirecting the optical path, reducing thickness, and improving sensitivity, while allowing for flexible space arrangement and aberration correction.
Implementation Method 1
The optical path along the first optical axis is redirected to a second optical axis by the first reflective surface, the optical path along the second optical axis is redirected to a third optical axis by the second reflective surface, the optical path along the third optical axis is redirected to a fourth optical axis by the third reflective surface
Implementation Method 2
Each of the plurality of lens elements has a light incident surface and a light emitting surface sequentially along the travelling direction of light on the optical path
Data Source
AI summary
A folded optical system includes an optical folding assembly and lens elements. The optical folding assembly has a first transmissive surface, a first reflective surface, a second reflective surface substantially the same interface as the first transmissive surface, a third reflective surface and a second transmissive surface sequentially along an optical path. The optical path reaches the first reflective surface via the first transmissive surface along a first optical axis to be sequentially redirected to a second optical axis, a third optical axis, and a fourth optical axis respectively by the first reflective surface, the second reflective surface, and the third reflective surface and reaches an image surface via the second transmissive surface. The lens elements at least include a first lens element located on the first optical axis. The first lens element with positive refractive power has a light incident surface being convex in a paraxial region thereof.