Annular Light Trap Structure for Stray Light Reduction in Imaging Lens
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Solution Overview
Problem
Conventional imaging lens assemblies face challenges in achieving high optical quality with short total track length, large image sensors, high pixel density, and wide angles due to inadequate light blocking, leading to stray light and decreased image quality.
Innovation Solution
An imaging lens assembly with an annular structure that includes specific through holes and frustum surfaces, designed to surround the optical axis and taper towards the holes, forming a light trap structure to intercept non-imaging light and improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional light blocking element is added to block non-imaging light, then stray light is reduced and image quality improves, but the total track length increases and large-angled imaging light is shaded causing decreased relative illumination
Solution Approach 1:
The patent introduces a light blocking structure on the image side of the imaging lens assembly, adding a new spatial dimension for light control. This allows blocking non-imaging light without extending the traditional optical path length, as the blocking occurs in a different spatial plane rather than increasing axial length.
Solution Approach 2:
The light blocking structure acts as an intermediary element positioned between the imaging lens and the image sensor. It selectively blocks non-imaging light rays while allowing imaging light to pass through, serving as a mediator that prevents stray light without interfering with the main optical path.
2Object-affected harmful factors
If a conventional light blocking element is added to block non-imaging light, then image quality improves, but the relative illumination decreases due to shading of large-angled imaging light
Solution Approach 1:
The light blocking structure is designed with specific geometric characteristics including a blocking surface area and an opening area. By controlling the ratio and positioning of these areas, the structure selectively blocks only the non-imaging light rays while preserving the transmission of large-angled imaging light, achieving local differentiation in light blocking behavior.
Solution Approach 2:
The patent optimizes parameters such as the position, area, and shape of the light blocking structure to achieve the desired light blocking effect. By adjusting these parameters, the system maintains high relative illumination while effectively blocking stray light, resolving the contradiction between image quality and illumination intensity.
3Length of stationary object
If the total track length is shortened to meet compact design requirements, then device size reduces, but the capability to block non-imaging light becomes insufficient
Solution Approach 1:
Instead of extending the optical path length to block stray light, the patent utilizes a different spatial dimension by placing the light blocking structure on the image side of the lens assembly. This allows effective stray light blocking within a compact total track length by exploiting lateral space rather than axial space.
4Measurement precision
If high pixel density and large image sensor are implemented to improve resolution, then image quality improves, but the complexity of the imaging lens assembly increases
Solution Approach 1:
The light blocking structure is integrated into the existing imaging lens assembly rather than being a separate component. By merging the light blocking function with the lens assembly structure, the patent avoids adding extra complexity while still providing effective stray light blocking for high-resolution imaging applications.
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 annular structure effectively reduces stray light and enhances image quality by trapping non-imaging light, aligning with the requirements of high-resolution and wide-angle imaging while maintaining a compact design.
Implementation Method 1
The first frustum surface of the annular structure and the second frustum surface of the annular structure gradually taper towards the direction away from the optical axis. The second frustum surface and the third frustum surface gradually taper towards the second through hole.
Data Source
AI summary
An imaging lens assembly has an optical axis and includes an annular structure located on an object side of the imaging lens assembly and surrounds the optical axis. The annular structure is located on an object side of the imaging lens assembly, surrounds the optical axis, and includes a first through hole, a second through hole, a first frustum surface, a second frustum surface and a third frustum surface. The first through hole is disposed on an object side of the annular structure, and the second through hole is disposed on an image side of the first through hole. The first frustum surface is disposed on the image side of the first through hole. The second frustum surface is disposed on an object side of the second through hole. The third frustum surface is disposed on an image side of the second through hole.