Variable-Angle Fresnel Lens Translation Edges for IR Sensor Field of View
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Solution Overview
Problem
Conventional Fresnel lenses fail to direct light rays with off-axis incident angles to IR sensors, resulting in a limited field of view and reduced motion detection capabilities.
Innovation Solution
A Fresnel lens array with translation edges oriented at varying angles, such as thirty degrees and one degree, to effectively direct both on-axis and off-axis light rays to IR sensors, enhancing the field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional Fresnel lenses use standard translation edges at one degree relative to the central axis, then the lens structure is simple and easy to manufacture, but light rays with off-axis incident angles cannot be directed to the IR sensor, resulting in limited field of view
Solution Approach 1:
The patent applies local quality by using different translation edge angles (one degree and thirty degrees) in different regions of the Fresnel lens. The first portion of lens elements uses one-degree angled translation edges for on-axis light rays, while the second portion uses thirty-degree angled translation edges for off-axis light rays. This localized differentiation allows the lens to handle multiple incident angles simultaneously, expanding the field of view without requiring complete structural redesign.
Solution Approach 2:
The Fresnel lens is segmented into multiple lens elements with different translation edge orientations. Specifically, the lens array includes first lens elements with one-degree angled translation edges and second lens elements with thirty-degree angled translation edges. This segmentation allows each portion to optimize for specific incident angles, collectively achieving enhanced field of view coverage.
2Reliability
If conventional Fresnel lenses use uniform translation edges, then manufacturing is straightforward, but motion detection capability is reduced due to limited field of view
Solution Approach 1:
Different portions of the lens are assigned different translation edge angles optimized for specific detection requirements. The thirty-degree angled edges in the second portion specifically address off-axis light rays from peripheral motion detection areas, while the one-degree edges handle central axis rays. This localized optimization enhances motion detection reliability across the entire field of view.
Solution Approach 2:
The patent introduces variability in the lens structure through multiple translation edge angles, creating a dynamic optical response that adapts to different incident angles. This allows the lens to dynamically handle both on-axis and off-axis light rays effectively, improving motion detection capability across varying spatial positions.
3Adaptability or versatility
If the lens uses only one translation edge angle, then the lens design is simple, but light rays with high incident angles fail to be directed to the IR sensor
Solution Approach 1:
The lens employs different translation edge angles in different regions: one-degree angled edges for on-axis light rays and thirty-degree angled edges for off-axis light rays with high incident angles. This local differentiation ensures that light rays from various angles are appropriately directed to the IR sensor, enhancing adaptability without requiring complete structural complexity.
Solution Approach 2:
The patent introduces asymmetry in the lens structure by using non-uniform translation edge angles. Instead of a symmetric one-angle design, the lens incorporates multiple angled translation edges (one degree and thirty degrees) to asymmetrically handle different incident angle ranges, thereby improving light ray directionality for both on-axis and off-axis rays.
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 Fresnel lens array significantly improves the field of view and motion detection capabilities by ensuring that light rays with high incident angles are directed to the IR sensors, thereby overcoming the limitations of conventional Fresnel lenses.
Implementation Method 1
A Fresnel lens array with translation edges oriented at varying angles, such as thirty degrees and one degree, to effectively direct both on-axis and off-axis light rays to IR sensors
Data Source
AI summary
A lens assembly includes a lens housing and a Fresnel lens array. The lens housing includes a first portion that defines an exterior surface and an interior surface, and a second portion. The second portion defines a cavity, where the interior surface is disposed within the cavity. The Fresnel lens array is disposed within the cavity and coupled to the interior surface. The Fresnel lens array includes a first lens element and a second lens element. The first lens element has first concentric grooves defined by first translation edges and first facets. The first translation edges are disposed at thirty degrees relative to a first center point of the first concentric grooves. The second lens element has second concentric grooves defined by second translation edges and second facets. The second translation edges are disposed at one degree relative to a second center point of the second concentric grooves.