Optical Element Haze Reduction via Temperature-Controlled Post Exposure
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Solution Overview
Problem
Haze in the non-recorded areas of optical elements with holograms, particularly in AR glass light guide plates, due to light scattering from the recording layer material, which degrades image quality and optical performance.
Innovation Solution
A method involving post exposure under specific conditions, including a temperature difference between recording and post exposure, higher light intensity during post exposure, and incoherent light sources, to reduce Haze in the non-recorded areas by controlling polymerization and preventing diffusion of polymerizable compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If post exposure is performed at the same temperature as recording exposure, then polymerization is accelerated in non-recorded areas, but Haze increases due to diffusion of polymerizable compounds
Solution Approach 1:
The patent applies parameter changes by performing post-exposure at a lower temperature than recording exposure. This temperature parameter change suppresses the diffusion of polymerizable compounds while still enabling polymerization acceleration in non-recorded areas, thereby resolving the contradiction between productivity improvement and haze reduction
2Productivity
If light intensity during post exposure is increased, then polymerization is accelerated more effectively, but temperature rise occurs causing increased Haze
Solution Approach 1:
The patent uses parameter changes by implementing lower temperature conditions during post-exposure. This compensates for the temperature rise caused by high light intensity, maintaining effective polymerization acceleration while preventing Haze formation from thermal effects
3Ease of manufacture
If conventional post exposure is performed without temperature control, then the process is simple, but Haze degrades image quality in AR glass applications
Solution Approach 1:
The patent introduces a temperature parameter change (lower temperature during post-exposure) to achieve both haze reduction and maintained image quality. While this adds temperature control to the process, it enables high-precision manufacturing for AR glass applications by suppressing the diffusion that causes Haze
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
Significantly reduces Haze in the non-recorded areas of optical elements, enhancing image quality and maintaining high diffraction efficiency for AR glass applications.
Implementation Method 1
a photopolymerization initiator causes a chemical reaction and becomes an active substance in the area of high light intensity among the interference fringes. This then acts on the polymerizable compound, causing it to polymerize.
Implementation Method 2
when the polymerizable compound polymerizes, diffusion of the polymerizable compound occurs from the periphery, causing a concentration distribution of the polymerizable compound or its polymerized product inside the recording layer.
Implementation Method 3
if there is a difference in refractive index between a matrix resin and a polymer generated from the polymerizable compound, the interference fringes are fixed in the recording layer as a difference in refractive index.
Implementation Method 4
when reproducing data, only a reproduction light is used, and the irradiated reproduction light causes diffraction according to the interference fringes.
Data Source
AI summary
A method for producing an optical element, comprising; performing recording exposure on a medium having a recording layer containing a polymerizable compound and a photopolymerization initiator; and further performing post exposure on the medium in a state where the temperature of the medium is lower than during the recording exposure. A method for producing an optical element, wherein the recording exposure is holographic recording exposure.