Six-Lens Optical Assembly for Vignetting and Thermal Stability
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Solution Overview
Problem
Existing wide-angle lens modules struggle to accommodate both visible and infrared light bands, often resulting in vignetting effects when used with large image sensing elements, and require multiple glass lenses to mitigate temperature-induced image issues, increasing cost and complexity.
Innovation Solution
The optical lens assembly comprises six lenses with specific refractive powers, including a third lens with carefully configured refractive index, central thickness, and entrance pupil diameter, satisfying conditions that enhance manufacturability and reduce temperature impact on imaging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide-angle lens module is used with an image sensing element having a large effective area, then the coverage area is improved, but the vignetting effect occurs
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices, focal lengths, and curvature radii of the six lens elements. Specifically, the combination of negative and positive refractive powers in alternating lens elements, along with precise control of thickness and air gap parameters, enables the system to maintain uniform illumination across large image sensing elements while achieving wide-angle coverage.
2Stability of the object's composition
If multiple glass lenses are used to solve image problems caused by temperature change, then the thermal stability is improved, but the cost and complexity increase
Solution Approach 1:
The patent employs composite materials by combining multiple lens elements made of different materials with distinct thermal expansion coefficients and refractive index temperature dependencies. This composite lens structure compensates for thermal effects through the complementary properties of the constituent materials, achieving thermal stability without requiring an excessive number of glass lenses.
3Use of energy by moving object
If the wide-angle lens module is designed for large aperture, then the light gathering ability is improved, but the manufacturability and temperature sensitivity worsen
Solution Approach 1:
The patent applies parameter changes by establishing specific mathematical relationships between the entrance pupil diameter, refractive indices, and focal lengths of the lens elements. The condition 2.64 < (nd3×CT3)/EPD < 4.55 optimizes the balance between light gathering ability and manufacturability, ensuring that large aperture lenses can be manufactured with reasonable tolerances while maintaining performance.
4Use of energy by moving object
If the wide-angle lens module is designed for large aperture, then the light gathering ability is improved, but the temperature impact on imaging quality worsens
Solution Approach 1:
The patent employs composite materials with carefully selected thermal properties in the lens elements. The combination of materials with different thermal characteristics in the six-lens configuration creates a thermally compensated optical system that maintains imaging quality across temperature variations while preserving large aperture light gathering capability.
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 improves the manufacturability of the optical lens assembly, reduces the impact of temperature changes on imaging quality, and enhances the optical lens assembly's ability to handle both visible and infrared light bands without vignetting.
Implementation Method 1
a refractive index of the third lens is nd3, a central thickness of the third lens along the optical axis is CT3, an entrance pupil diameter of the optical lens assembly is EPD, and the following condition is satisfied: 2.64□(nd3*CT3)/EPD□4.55
Implementation Method 2
a first lens with negative refractive power, comprising an object-side surface and an image-side surface, wherein the object-side surface of the first lens is concave near the optical axis; a second lens with negative refractive power, comprising an object-side surface and an image-side surface; a third lens with positive refractive power
Data Source
AI summary
An optical lens assembly includes a stop, and includes, in order from the object side to the image side: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens; wherein a refractive index of the third lens is nd3, a central thickness of the third lens along the optical axis is CT3, an entrance pupil diameter of the optical lens assembly is EPD, and the following condition is satisfied: 2.64□(nd3*CT3)/EPD□4.55.