Folded Wide-Angle Lens Layout for Edge Illumination in Smartphones
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Solution Overview
Problem
Current ultra-wide angle imaging systems for smartphones suffer from reduced relative illumination at the edges, leading to decreased image quality and increased distortion, which cannot be accommodated within the housing of a smartphone without compromising image quality or requiring time-consuming post-processing.
Innovation Solution
A compact optical imaging apparatus with a folded wide angle imaging lens system using a prism to reflect light between two optical axes, reducing chief ray angles and increasing optical path length, thereby improving relative illumination and image quality without increasing depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the field of view is increased in conventional compact up-right lens architectures, then the field of view expands, but the relative illumination towards the edges of the image decays significantly
Solution Approach 1:
The patent introduces a folded optical path using a prism to reflect light at approximately 45 degrees, transforming a linear optical arrangement into a three-dimensional folded configuration. This allows the optical axis to be bent, effectively increasing the optical path length and allowing better control of chief ray angles without increasing the linear footprint, thereby improving relative illumination at image edges while maintaining wide field of view
2Illumination intensity
If distortion is introduced to increase relative illumination, then the illumination improves, but the image quality deteriorates due to unnatural appearance of geometrical details
Solution Approach 1:
The patent changes the optical parameters by folding the optical path and using a negative optical power in the first optics followed by positive optical power in the second optics. This parameter change allows control of chief ray angles and improvement of relative illumination without introducing the geometric distortion that would compromise image quality
3Reliability
If distortion compensation is performed by software algorithms in post-processing, then the image quality improves, but the processing time increases and frame rate decreases
Solution Approach 1:
The patent performs preliminary optical correction by designing the lens system with a folded optical path and specific optical power distribution that inherently controls chief ray angles and minimizes distortion at the optical level. This preliminary optical action eliminates the need for time-consuming software-based post-processing distortion compensation, maintaining both image quality and high frame rates
4Illumination intensity
If the chief ray angles are reduced to improve relative illumination, then the illumination improves, but the total track length of the lens system increases
Solution Approach 1:
The patent uses a prism to fold the optical path at approximately 45 degrees, transforming the optical arrangement from a linear configuration into a three-dimensional folded structure. This allows the optical path to be extended effectively, enabling better control of chief ray angles and improved relative illumination without increasing the linear total track length that would be constrained by smartphone housing dimensions
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 provides a compact imaging apparatus with a full field of view of 130-180 degrees, achieving improved relative illumination and image quality across the entire field of view, reducing distortion, and maintaining a compact form factor suitable for smartphones.
Implementation Method 1
the prism is configured to reflect light from the first optics to the second optics
Implementation Method 2
The entrance surface of the prism comprises a paraxial region that is concave
Data Source
AI summary
An ultra-wide angle imaging apparatus is provided, comprising a first optics having a first optical axis, a second optics having a second optical axis, and a prism placed at an intersection of the first and second optical axis. The prism is configured to reflect light from the first optics to the second optics and the second optics is configured to transmit light from the prism to an image surface. The first optics has a negative optical power, the second optics has a positive optical power, and the prism has an entrance surface for receiving light from the first optics and a reflective inner surface for reflecting light to the second optics. The entrance surface of the prism comprises a paraxial region that is concave.