Seven-Lens Optical System Confocal Visible Infrared Imaging
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Solution Overview
Problem
Conventional optical systems for portable electronic devices face challenges in capturing high-quality images in low-light environments, particularly in dark conditions, and require expensive and space-consuming IR cut filters to differentiate between visible and infrared light, which hinders miniaturization efforts.
Innovation Solution
A compact optical image capturing system utilizing a combination of refractive powers and convex/concave surfaces of seven-piece lenses, designed to minimize the difference in focal lengths for visible and infrared light, allowing for a 'confocal' effect without IR cut filters, using materials and lens parameters to optimize image formation and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical systems use five or six lenses to achieve high optical performance, then imaging quality is improved, but system size and complexity increase
Solution Approach 1:
The patent divides the optical system into seven distinct lens elements, each with specific refractive power and surface characteristics (convex/concave combinations). This segmentation allows each lens to be optimized for specific functions (light gathering, focal length control, aberration correction) while maintaining overall system performance and enabling compact configuration.
Solution Approach 2:
The patent optimizes key parameters including the ratio of total track length to focal length (TTL/f) ≤ 2.0, f-number (f/HEP) between 1.0-10.0, and half field of view angle (HAF) between 20-60 degrees. These parameter changes enable the system to achieve high imaging quality in a compact form factor with controlled complexity.
2Adaptability or versatility
If IR cut filters are added to differentiate visible and infrared light, then spectral discrimination is improved, but system size and cost increase
Solution Approach 1:
The patent designs the seven-piece lens system to simultaneously handle both visible and infrared wavelengths without requiring separate IR cut filters. The lens materials and surface configurations are optimized to achieve near-confocal imaging for both spectral ranges, making the optical system universal for dual-spectrum applications and eliminating the need for additional filtering elements.
Solution Approach 2:
The patent extracts and eliminates the IR cut filter from the optical path by designing lenses that inherently provide spectral discrimination through their refractive properties. The seventh lens with specific convex/concave surface combinations and material selection enables the system to focus visible and infrared light at nearly the same plane without requiring external filtering components.
3Illumination intensity
If aperture is increased to capture more light in dark environments, then light intake is improved, but aberration control becomes more difficult
Solution Approach 1:
The patent employs composite lens design with seven elements having different refractive indices and Abbe numbers. This composite structure allows the system to maintain large aperture for high light intake while using material properties to correct chromatic and spherical aberrations. The combination of high and low dispersion materials enables effective aberration control across the aperture.
Solution Approach 2:
The patent replaces mechanical aperture restriction with optical design solutions. Instead of limiting aperture to control aberrations, the system uses precisely engineered lens surface curvatures (convex/concave combinations) and refractive power distributions to correct aberrations while maintaining large aperture for maximum light intake in dark environments.
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 system enhances light intake and imaging quality, enabling effective image capture in both visible and infrared spectra, reducing system size and cost while maintaining high performance, suitable for applications like facial recognition and surveillance cameras.
Implementation Method 1
Optical image capturing system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens sequentially arranged from an object side to an image side along an optical axis
Implementation Method 2
reduce the difference between the imaging focal length of visible light and imaging focal length of infrared light, in order to achieve the near 'confocal' effect
Data Source
AI summary
An optical image capturing system includes, along the optical axis in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. At least one lens among the first to the sixth lenses has positive refractive force. The seventh lens can have negative refractive force, and both surfaces thereof are aspheric. At least a surface of the seventh lens has an inflection point. The lenses in the optical image capturing system which have refractive power include the first to the seventh lenses. The optical image capturing system can increase aperture value and improve the imaging quality for use in compact cameras.