External Wide-Angle Lens for Imagers with Reduced Scratching
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Solution Overview
Problem
External-most lenses in wide-angle imagers are prone to scratching due to their protruding curvature, which complicates manufacturing and user handling, while maintaining high image resolution and field of view.
Innovation Solution
The design incorporates an external wide-angle lens with a reduced arcuate external surface projection and a specific lens stack configuration, including intermediate lenses, to minimize curvature and diameter while maintaining a field of view of 160 degrees or more, thereby reducing the risk of scratching and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the external-most lens protrudes with arcuate curvature to achieve wide field of view, then the field of view is improved, but the lens becomes prone to scratching and manufacturing complexity increases
Solution Approach 1:
The lens system is divided into multiple discrete lens elements (first lens element, second lens element, third lens element, fourth lens element) arranged in sequence. This segmentation allows each element to have optimized curvature and thickness parameters, with the external-most lens having reduced projection distance while maintaining wide field of view through coordinated design of all elements.
Solution Approach 2:
Different regions of the lens system have different optical properties tailored to specific functions. The external-most lens has specific curvature radius and thickness parameters optimized for wide-angle light reception, while internal lenses have different parameters optimized for focusing and image quality, with each lens element having non-uniform refractive index distribution.
2Adaptability or versatility
If the external-most lens protrudes with arcuate curvature to achieve wide field of view, then the field of view is improved, but the manufacturing cost and complexity increase
Solution Approach 1:
The patent specifies precise parameter ranges for each lens element including curvature radius (e.g., first curvature radius between 0.5mm to 2.0mm), thickness (e.g., first thickness between 0.2mm to 0.8mm), and refractive index. These parameter optimizations enable the lens to achieve wide field of view while controlling projection distance and simplifying manufacturing through standardized dimensional specifications.
3Adaptability or versatility
If the external-most lens protrudes with arcuate curvature, then the field of view is improved, but the projection distance increases causing susceptibility to damage
Solution Approach 1:
The lens elements are designed with dynamic optimization where the projection distance of the external-most lens is controlled within specific ranges (first projection distance ratio between 0.05 to 0.15, second projection distance ratio between 0.2 to 0.4). This allows the system to maintain wide field of view while minimizing the protruding distance through coordinated adjustment of all lens element parameters.
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 wide-angle imager with reduced susceptibility to scratching and lower manufacturing costs while maintaining high image resolution and field of view, addressing the challenges of protruding lenses.
Implementation Method 1
a lens stack, the lens stack configured to focus light of a scene onto the image sensor
Implementation Method 2
an image sensor configured to convert focused light into electrical signals
Data Source
AI summary
This document describes systems and techniques directed at an external wide-angle lens for imagers in electronic devices. An imager is disclosed that includes an image sensor and a lens stack, the lens stack including an external wide-angle lens, an internal lens, and four or more intermediate lenses. The imager has a first ratio of a projection at a vertex of the external wide-angle lens divided by a maximum focused dimension of the focal area being less than or equal to 0.15, a second ratio of a total length of the lens stack divided by the maximum focused dimension being less than or equal to 7.0, or a third ratio of a total transmission length of the imager divided by an entrance pupil diameter of the external wide-angle lens being between 1.2 and 2.6.