Five-Lens Optical System Confocal Imaging
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Solution Overview
Problem
Conventional optical systems in portable electronic devices struggle to achieve high optical performance, especially in low-light environments, and require IR cut filters that occupy space and increase costs, making it challenging to design miniaturized surveillance cameras that can capture images effectively across both visible and infrared spectra.
Innovation Solution
A compact optical image capturing system utilizing a combination of refractive powers and convex/concave surfaces in five-piece lenses, which reduces the difference between visible and infrared focal lengths, achieving a near-confocal effect without IR cut filters, allowing for improved light intake and imaging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical systems use three or four lenses, then the device complexity is reduced, but the optical performance and light intake are insufficient
Solution Approach 1:
The patent combines five lenses into a unified optical system where each lens contributes to both visible and infrared light management. The lenses are integrated with specific refractive indices and dispersive properties that work together to achieve confocal imaging for both spectral ranges simultaneously, rather than using separate optical paths or filters.
Solution Approach 2:
Each lens in the five-lens system is designed to handle both visible and infrared wavelengths. The optical elements are configured with specific refractive index ranges (1.45-1.70 for visible, 1.40-1.65 for infrared) and dispersive properties that enable them to function across both spectral ranges, eliminating the need for wavelength-specific components.
2Measurement precision
If IR cut filters are used to capture visible light, then the image fidelity is improved, but the device size and cost increase
Solution Approach 1:
The patent removes the IR cut filter from the optical system entirely. Instead of using a filter to block infrared light, the system uses the inherent optical properties of five lenses with specific refractive indices and dispersive characteristics to focus both visible and infrared light onto the same image sensor plane, achieving spectral separation through optics rather than filtration.
Solution Approach 2:
The five lenses act as intermediaries that mediate between the incoming visible and infrared light and the image sensor. By carefully selecting lens materials with specific refractive index differences between visible and infrared ranges, the system creates a confocal effect where both wavelengths are focused at the same plane without requiring additional filtering components.
3Illumination intensity
If the aperture is increased to capture more light in dark environments, then the light intake is improved, but the optical performance deteriorates
Solution Approach 1:
The patent optimizes multiple optical parameters simultaneously: refractive indices (1.45-1.70 for visible light), dispersive properties (Abbe numbers 20-50 for visible, 15-40 for infrared), and lens spacing. These parameter changes enable the system to maintain high optical performance with larger aperture by reducing chromatic aberration and improving focus accuracy across different wavelengths.
4Manufacturing precision
If five-piece lenses with specific refractive powers are used, then the imaging quality is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent specifies composite material properties for the five lenses, with refractive indices ranging from 1.45 to 1.70 for visible light and corresponding dispersive properties. These material specifications enable precise control over chromatic aberration and focal length differences between visible and infrared wavelengths, achieving confocal imaging while using commercially available optical materials that balance performance and manufacturability.
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 across both visible and infrared spectra without the need for IR cut filters, thus reducing size and cost while maintaining high optical performance.
Implementation Method 1
an optical image capturing system includes, along an optical axis from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens
Implementation Method 2
the object-side surface and the image-side surface of the fifth lens are aspheric surfaces
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, and a fifth lens. At least one lens among the first to the fifth lenses has positive refractive force. The fifth lens can have negative refractive force. The lenses in the optical image capturing system which have refractive power include the first to the fifth lenses. The optical image capturing system can increase aperture value and improve the imaging quality for use in compact cameras.