Three-Lens Imaging System for Compact Infrared Motion Capture
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Solution Overview
Problem
There is a growing demand for compact imaging lenses that can accommodate both conventional photography and infrared motion capture applications, requiring lenses with wide viewing angles and high image quality, while being optimized for slim and portable electronic devices.
Innovation Solution
The imaging lens system comprises a combination of three lens elements with specific refractive powers and surface curvatures, including a first lens with positive refractive power, a second lens with positive refractive power and aspheric surfaces, and a third lens with negative refractive power, optimized for optical wavelengths between 780 nm and 950 nm, to reduce the total track length and increase the viewing angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the total track length of the imaging lens system is reduced for compact device integration, then the lens system becomes more suitable for slim and portable electronic devices, but the image quality and viewing angle may deteriorate
Solution Approach 1:
The imaging lens system is divided into three distinct lens elements with specific refractive powers and surface curvatures. The first lens element has positive refractive power with convex object-side and image-side surfaces, the second lens element has positive refractive power with aspheric surfaces, and the third lens element has negative refractive power. This segmentation allows each element to contribute differently to the overall optical performance, enabling compact design while maintaining image quality through optimized distribution of optical functions across multiple elements.
Solution Approach 2:
Different regions of the lens elements have different surface characteristics. The object-side surface of the first lens element has positive curvature in the paraxial region, while the image-side surface has positive curvature. The second lens element has aspheric surfaces with specific curvature relationships. The third lens element has a concave object-side surface and an image-side surface that is concave in the paraxial region but convex in the peripheral region. These local quality variations enable precise control of light paths to maintain image quality in a compact form.
2Adaptability or versatility
If the viewing angle is increased for wide-angle photography and motion capture, then the capturing range is extended, but the total track length and device size increase
Solution Approach 1:
The lens system employs aspheric surfaces on the second lens element to dynamically adapt light paths across different field angles. The aspheric surfaces enable the system to maintain wide viewing angles by effectively controlling off-axis light rays without requiring a proportionally longer optical path, thus achieving wide-angle performance in a compact configuration.
Solution Approach 2:
The patent specifies precise parameter relationships: the curvature radius of the object-side surface of the first lens element (R1) and image-side surface (R2) satisfy −0.5 < (R1+R2)/(R1−R2) < 0.5, and the focal length of the first lens element (f1) and second lens element (f2) satisfy 0.3 < f1/f2 < 1.5. These parameter optimizations enable the system to achieve wide viewing angles while controlling the total track length, as the specific curvature and focal length relationships efficiently manage light convergence and divergence across the wide field of view.
3Adaptability or versatility
If the lens system is optimized for infrared wavelength range for motion capture, then motion sensing capability is enhanced, but the design complexity increases
Solution Approach 1:
The imaging lens system is designed to serve multiple functions: it can perform conventional photography and simultaneously optimize for infrared motion capture applications. The three-lens configuration with specific refractive powers and surface curvatures creates a multi-functional system that operates effectively across different wavelength ranges, eliminating the need for separate optical systems for visible and infrared applications.
Solution Approach 2:
The patent specifies that the second and third lens elements are made of plastic material, while the first lens element material is not specifically constrained. This composite material approach allows optimization for infrared transmission characteristics while maintaining manufacturing feasibility. Plastic materials can be formulated to have favorable infrared transmission properties, enabling motion capture functionality without requiring complex multi-material construction.
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 effectively reduces the total track length of the imaging lens system, enhances the viewing angle, and facilitates compact, wide-angle applications, improving image quality and photosensitivity for both conventional photography and infrared motion capture.
Implementation Method 1
a first lens element with positive refractive power having a convex object-side surface at a paraxial region and a convex image-side surface at the paraxial region
Implementation Method 2
a plastic second lens element with positive refractive power having a concave object-side surface at the paraxial region, a convex image-side surface at the paraxial region, and both of the object-side and image-side surfaces thereof being aspheric
Implementation Method 3
a plastic third lens element with negative refractive power having a concave object-side surface at the paraxial region, a concave at the paraxial region and convex at a peripheral region image-side surface, and both of the object-side and image-side surfaces thereof being aspheric
Data Source
AI summary
This invention provides an imaging lens system, in order from an object side to an image side comprising: a first positive lens element having a convex object-side surface at a paraxial region and a convex image-side surface at the paraxial region; a plastic positive second lens element having a concave object-side surface at the paraxial region, a convex image-side surface at the paraxial region, and both of the object-side and image-side surfaces being aspheric; and a plastic negative third lens element having a concave object-side surface at the paraxial region, a concave at the paraxial region and convex at a peripheral region image-side surface, and both of the object-side and image-side surfaces being aspheric.