Imaging Lens Assembly Non-Cylindrical Barrel Stray Light
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Solution Overview
Problem
Conventional imaging lens assemblies suffer from excessive surface reflections and stray light issues due to the straight cylindrical shape of the plastic barrel, which limits image quality and requires complex light path analysis.
Innovation Solution
The imaging lens assembly features a plastic barrel with a non-cylindrical shape, including an object-side outer surface, first and second inner surfaces that are substantially parallel, and a light-absorbing coating on the plastic lens elements. The spacer includes a central hole and surfaces configured to minimize surface reflections and enhance light trapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a straight cylindrical plastic barrel is used, then the manufacturing is simple, but surface reflections and stray light increase
Solution Approach 1:
The plastic barrel is designed with a tapered shape where the object-side end has a smaller diameter than the image-side end. This asymmetric geometry creates effective light trapping by directing stray light at angles that prevent it from escaping back through the lens elements, thereby reducing surface reflections and improving image quality while maintaining manufacturing feasibility through standard injection molding processes.
2Object-generated harmful factors
If a tapered plastic barrel (narrow front, wide back) is used, then stray light is reduced, but manufacturing complexity increases
Solution Approach 1:
The plastic barrel geometry is optimized by adjusting the taper angle and diameter ratios between the object-side and image-side ends. By carefully selecting these parameters, the design achieves effective light trapping and stray light reduction while maintaining compatibility with standard injection molding processes, thus avoiding excessive manufacturing complexity.
3Object-generated harmful factors
If multiple light blocking sheets are added, then stray light is blocked, but the number of components and assembly complexity increases
Solution Approach 1:
The light blocking function is extracted from separate light blocking sheet components and integrated directly into the plastic barrel structure through the tapered geometry. This design approach eliminates the need for multiple discrete light blocking sheets and their associated assembly steps, reducing component count and assembly complexity while maintaining effective stray light blocking.
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 design effectively reduces surface reflections and stray light, improving image quality by simplifying light paths and enhancing the light trap structure, thereby addressing the limitations of conventional imaging lens assemblies.
Implementation Method 1
A light-absorbing coating is disposed on the plastic lens element
Implementation Method 2
surface reflections of the incident light M2 and the incident light M3 occur repeatedly in the engaging structures of the front lens group so as to form a reflected light R2 and a reflected light R3 projecting on the image surface 3600
Data Source
AI summary
An imaging lens assembly includes a plastic barrel and a lens set, and the lens set is disposed in the plastic barrel. The plastic barrel includes an object-side outer surface, a first inner surface and a second inner surface. The lens set has an optical axis, and includes, in order from an object side to an image side thereof, at least one plastic lens element and a spacer. A light-absorbing coating is disposed on the plastic lens element. The spacer includes an object-side connecting surface and a relative surface. When the object-side connecting surface is connected with a neighboring object-side optical element, the relative surface is out of touch with the neighboring object-side optical element. There is an overlap between the second inner surface and the relative surface along a direction parallel to the optical axis.