Plastic Optical Lens Assembly With IR Filtering and Low Angle Reflection
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Solution Overview
Problem
Conventional optical lens assemblies face issues with infrared filtering, such as light-leakage and reflection at large angles, leading to color shift and reduced imaging quality, and the use of blue glass elements is costly, fragile, and difficult to miniaturize.
Innovation Solution
An optical lens assembly with at least three plastic optical lens elements, each with an infrared filtering coating having two different refractive indices, and incorporating long-wavelength absorbing materials, designed to control incident angles and transmittance within specific limits, reducing the need for blue glass and enhancing imaging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an infrared filtering coating is applied on the surface of a plastic lens element, then the number of elements can be reduced, but severe reflection and light-leakage occur at large incident angles
Solution Approach 1:
The patent changes the physical parameters of the lens element by using an aspheric surface design with specific curvature radius constraints (|R1|≥5mm, |R2|≥5mm) and controlling the maximum incident angle (AICmax≤40 degrees). This parameter optimization reduces the angle-dependent reflection and light-leakage issues while maintaining the infrared filtering function with fewer elements.
Solution Approach 2:
The patent combines infrared filtering coating with plastic lens material that has specific refractive index properties. The composite structure of coating plus controlled-aspheric plastic element creates a system that achieves both infrared filtering and reduced off-axis reflection without requiring additional blue glass elements.
2Object-generated harmful factors
If blue glass planar element is used for infrared filtering, then light-leakage problem is solved, but manufacturing cost increases and miniaturization becomes difficult
Solution Approach 1:
The patent replaces expensive blue glass with plastic lens elements that have infrared filtering capability. Plastic materials are cheaper, easier to manufacture, and enable miniaturization while achieving the same light-leakage prevention function through coating and aspheric design.
Solution Approach 2:
The patent changes from planar blue glass surfaces to aspheric plastic surfaces with controlled curvature radii (|R1|≥5mm, |R2|≥5mm). This parameter change enables better optical performance with plastic materials, reducing light-leakage while facilitating miniaturization and lowering manufacturing costs.
3Manufacturing precision
If the number of lens elements is increased to improve imaging quality, then aberration correction improves, but the size of the lens assembly increases
Solution Approach 1:
The patent designs each lens element to perform multiple functions: focusing light, correcting aberrations, and providing infrared filtering. The aspheric surfaces with controlled curvature radii enable single elements to achieve what would traditionally require multiple separate elements, reducing overall assembly size while maintaining imaging quality.
Solution Approach 2:
The patent uses aspheric surface parameters (|R1|≥5mm, |R2|≥5mm) and controls the maximum incident angle (AICmax≤40 degrees) to optimize the optical path. These parameter changes allow fewer elements to achieve better aberration correction and maintain compact size by improving the efficiency of each individual element.
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 solution effectively minimizes light-leakage and reflection, reduces manufacturing costs, and enables miniaturization while maintaining high imaging quality and durability, addressing the limitations of conventional methods.
Implementation Method 1
reflective coating technique, which leads to interference, will cause reflection and light-leakage
Implementation Method 2
reflective coating technique, which leads to interference
Implementation Method 3
At least one of the optical lens elements includes a long-wavelength absorbing material
Data Source
AI summary
An optical lens assembly includes at least three optical lens elements. At least one of the optical lens elements includes an infrared filtering coating, the optical lens element including the infrared filtering coating is made of a plastic material, the infrared filtering coating is arranged on an object-side surface or an image-side surface of the optical lens element, a surface of the optical lens element including the infrared filtering coating is aspheric, and the infrared filtering coating includes at least two different refractive indices. At least one of the optical lens elements includes a long-wavelength absorbing material, and the optical lens element including the long-wavelength absorbing material is made of a plastic material.