Folded Camera Lens Design for Large Aperture and Low Height
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Solution Overview
Problem
There is a need for a folded camera design that maximizes the lens optical aperture while maintaining a minimal height to accommodate the industrial design constraints of host devices such as smartphones and tablets, while also improving optical properties by increasing the amount of light reaching the image sensor.
Innovation Solution
The design employs a folded lens assembly with a plurality of lens elements, including a first lens element with positive refractive power and a second lens element with negative refractive power, along with additional elements, to achieve a large front clear aperture and optimize the ratio of the image sensor diagonal length to the clear aperture of the last lens element, thereby enhancing optical performance and aperture size within a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the optical aperture of the lens is increased to improve optical properties and light intake, then the optical performance is improved, but the height of the camera increases
Solution Approach 1:
The patent introduces an optical path folding element (prism or mirror) that folds the optical path at a 45-degree angle, changing the light propagation direction from perpendicular to parallel with the back surface. This dimensional change allows the optical aperture to be enlarged in the lateral direction without increasing the camera height in the vertical direction, effectively resolving the contradiction between light intake and camera thickness.
2Length of stationary object
If the camera height is reduced to meet industrial design constraints, then the device thickness is minimized, but the optical aperture of the lens is limited
Solution Approach 1:
By folding the optical path using a prism or mirror at a 45-degree angle, the patent redirects light propagation from a vertical path to a horizontal path. This allows the optical aperture to be maximized in the lateral dimension while keeping the camera height minimal in the vertical dimension, effectively decoupling these two parameters and allowing independent optimization of each.
3Length of stationary object
If a folded optical path is introduced to reduce camera height, then the device thickness is reduced, but the device complexity increases
Solution Approach 1:
The patent introduces an optical path folding element (prism or mirror) as an intermediary component that simplifies the overall system architecture. Rather than attempting to design a complex lens system that achieves both small height and large aperture simultaneously, the folding element acts as a mediator that decouples these requirements, allowing each to be optimized independently through standard optical components.
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
This configuration allows for a compact folded camera with improved optical performance and increased light intake, achieving a high optical aperture while maintaining a minimal height, thus addressing the design constraints and enhancing image quality.
Implementation Method 1
an optical path folding element (referred to hereinafter as "OPFE") e.g. a prism or a mirror (otherwise referred to herein collectively as "reflecting element") is added in order to tilt the light propagation direction from perpendicular to the smart-phone back surface to parallel to the smart-phone back surface
Implementation Method 2
a first lens element L1 with a clear aperture CA(S1) and a second lens element L2 with a clear aperture CA(S3), wherein CA(S1)/CA(S3)>1.2
Data Source
AI summary
Folded lens modules and assemblies characterized by low height and large entrance pupil (clear aperture), designed for folded cameras in consumer electronics and specifically in mobile phones. In some embodiments, a folded lens assembly comprises a plurality of lens elements that include, in order for an object side to an image side, a first lens element L1 with a clear aperture CA(S1) and a second lens element L2 with a clear aperture CA(S3), wherein CA(S1)/CA(S3)>1.2 and wherein the lens assembly has a ratio between an image sensor diagonal length SDL and a clear aperture of a last lens element surface CA(S2N), SDL/CA(S2N)>1.5.