Resin Composite Optical Element UV Blocking
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Solution Overview
Problem
Conventional resin composite-type optical elements using photocurable resin struggle to cut off ultraviolet light due to the polymerization initiator being excited by UV light, making it difficult to produce an optical element with sufficient UV blocking properties.
Innovation Solution
A resin composite-type optical element is designed with a coat layer on the base material surface having specific reflectance properties and a resin layer comprising bifunctional fluorinated (meth)acrylate, (meth)acrylate with a fluorene structure, a photopolymerization initiator, and a benzotriazole type ultraviolet absorber, which absorbs UV light effectively, allowing for reduced transmittance in the UV range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photocurable resin is used for the resin layer, then curing time is shorter and facilities cost is reduced, but the optical element becomes transparent to ultraviolet light
Solution Approach 1:
The patent changes the chemical composition parameters of the resin layer by incorporating specific ultraviolet absorbers (benzotriazole type or those with molar absorption coefficient ≥500 at 380 nm) and photostabilizers (hindered amine type) into the photocurable resin formulation. This allows the resin to maintain its photocurability while gaining ultraviolet absorption capabilities, thus resolving the contradiction between short curing time and UV blocking performance
Solution Approach 2:
The patent creates a composite resin material system combining photocurable components (polymerizable monomers/oligomers and photopolymerization initiators) with ultraviolet absorbers and photostabilizers. This composite formulation enables the resin layer to simultaneously achieve rapid photocuring and effective ultraviolet light cutoff, addressing both the productivity improvement and harmful factor reduction requirements
2Object-affected harmful factors
If ultraviolet absorber is added to the resin layer, then ultraviolet light transmittance is reduced, but the resin precursor may not be properly cured
Solution Approach 1:
The patent segments the ultraviolet spectrum absorption function from the polymerization initiation function by selecting photopolymerization initiators that activate at wavelengths different from those absorbed by the ultraviolet absorbers. This allows the resin precursor to be properly cured by the initiator while the ultraviolet absorbers block harmful UV light, resolving the contradiction between UV blocking and curing completeness
Solution Approach 2:
The patent carefully controls the concentration parameters of ultraviolet absorbers and photostabilizers within specific ranges to ensure they provide sufficient UV blocking without interfering with the photopolymerization process. This parameter optimization allows both UV cutoff and proper curing to be achieved simultaneously
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 enables the production of resin composite-type optical elements that effectively cut off ultraviolet light, even when using photocurable resin, by ensuring the resin layer absorbs UV light, thereby preventing its transmission and enhancing light resistance.
Implementation Method 1
the resin layer comprises a plurality of resin layers, which satisfy at least one of the following conditions: a) the layers are formed on one surface of the base material; and b) the layers are formed on both surfaces of the base material, and at least one of the plurality of resin layers is the first resin layer. At least one layer of the first resin layer is preferably a cured product of a precursor composition containing: a bifunctional fluorinated (meth)acrylate; a bifunctional (meth)acrylate with a fluorene structure; a photopolymerization initiator; and a benzotriazole type ultraviolet absorber, or an ultraviolet absorber having a molar absorption coefficient of not less than 500 at the wavelength of 380 nm.
Implementation Method 2
the resin precursor is unlikely to cure unless it is highly transparent to the ultraviolet light. As a result, the optical element produced becomes considerably transparent to the ultraviolet light.
Implementation Method 3
it has a coat layer on a surface of the base material opposite to the resin layer, and the surface on the coat layer side has a reflectance of not more than 1% for light of wavelengths from 400 nm to 700 nm and not less than 2% for the light of the wavelength of 360 nm.
Data Source
Figure 1(A)~1(C)
Figure 2(A)~2(E)
Figure 3(A)~3(E)
AI summary
An object of the present invention is to provide a resin composite-type optical element capable of cutting off ultraviolet light even though it uses a photocurable resin. A resin composite-type optical element of the present invention is a resin composite-type optical element having a base material and a resin layer, and the resin layer has at least a first resin layer which is a molded product of a photocurable resin and which has an internal transmittance of not less than 85% for light of the wavelength of 400 nm in the thickness of 100 µm and an internal transmittance of not more than 3% for light of the wavelength of 360 nm in the thickness of 100 µm.