Optical Construction with Mask Layer and Microlenses
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Solution Overview
Problem
Existing optical constructions using metal masks suffer from unwanted specular reflection and poor shape definition of through openings in polymeric layers, leading to broad peaks in optical transmittance and undesired cross-talk.
Innovation Solution
A radiation-cured optically opaque mask layer with a low crosslinking density and high molecular weight oligomer is used, which provides through openings with sharp shape definition, high circularity, and uniform area distribution, aligned with microlenses for improved optical transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polymeric mask layer is used instead of metal mask, then the harmful specular reflection is reduced, but the shape definition of through openings becomes poor leading to broad transmittance peaks
Solution Approach 1:
The patent changes the physical and chemical parameters of the mask layer by using a photopolymerizable composition with specific oligomer molecular weights (500-5000 Da) and low crosslinking density. This parameter optimization enables the polymeric material to achieve sharp shape definition comparable to metal masks while maintaining the advantage of reduced specular reflection. The controlled crosslinking density and oligomer selection create a material that can be precisely ablated by laser to form well-defined through openings.
Solution Approach 2:
The patent employs a composite photopolymerizable composition containing oligomers, monomers, photoinitiators, and optically absorptive materials. This composite material combines the benefits of polymeric flexibility and ease of fabrication with the optical properties needed for sharp transmittance peaks. The composite formulation allows tuning of both the mechanical properties for shape retention and the optical properties for laser ablation precision.
2Illumination intensity
If the mask layer thickness is reduced to improve optical transmittance, then the peak transmittance increases, but the shape definition of through openings deteriorates
Solution Approach 1:
The patent optimizes the thickness parameter of the mask layer to a specific range (1-10 micrometers) that balances optical transmittance and shape definition. Within this optimized thickness range, the photopolymerizable composition maintains sufficient structural integrity to support well-defined through openings while allowing adequate light transmission. The low crosslinking density and specific oligomer selection enable this thickness optimization by providing the right balance of rigidity and laser ablation responsiveness.
3Ease of manufacture
If conventional photopolymerizable compositions are used, then the manufacturing process is simple, but the through openings exhibit poor shape definition with low circularity
Solution Approach 1:
The patent modifies the composition parameters by selecting oligomers with specific molecular weights (500-5000 Da) and controlling the crosslinking density to be low. These parameter changes result in a material that responds more predictably to laser ablation, producing through openings with high circularity (greater than 0.75 for at least 20% of openings). The simplified manufacturing process is maintained through the use of standard photopolymerization techniques, but the optimized composition parameters enable superior shape definition.
Solution Approach 2:
The patent replaces mechanical drilling or punching methods with laser ablation using a photopolymerizable composition. This substitution enables precise control of through opening shape and circularity while maintaining ease of manufacture. The laser ablation process, combined with the optimized photopolymerizable composition, produces clean, circular openings without the mechanical stress and deformation associated with traditional mechanical methods.
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 achieves a sharp peak in optical transmittance with a high peak transmittance and narrow full width at half maximum, reducing cross-talk and enhancing the optical performance of the construction.
Implementation Method 1
a radiation cured optically opaque mask layer disposed on the second major surface of the lens film
Implementation Method 2
a plurality of laser-ablated through openings therein
Implementation Method 3
a radiation cured optically opaque mask layer
Data Source
AI summary
An optical construction includes a lens film having an outermost structured first major surface and an opposing outermost substantially planar second major surface. The first major surface includes a plurality of microlenses. A radiation cured optically opaque mask layer is disposed on the second major surface of the lens film. The mask layer has an average thickness of less than about 10 microns and defines a plurality of laser-ablated through openings therein. The through openings are aligned to the microlenses in a one-to-one correspondence, such that for a light incident on the structured first major surface along an incident direction forming an incident angle with the second major surface, an optical transmittance of the optical construction as a function of a transmitted angle includes a first transmitted peak having a first peak transmittance T1≥40%. The first transmitted peak can be within about 10 degrees of the incident angle.