Core-shell particle light-shielding film for lens stress reduction
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Solution Overview
Problem
Existing light-shielding films for optical elements face challenges in reducing stress on lenses due to their formation on thinner edges, managing thermal shock, and maintaining washability without peeling during ultrasonic cleaning, while also providing high anti-internal reflection performance.
Innovation Solution
A light-shielding film and paint composition incorporating core-shell particles with a higher elastic modulus in the surface layer than the center portion, combined with inorganic particles and a resin, to reduce stress on lenses, enhance thermal shock resistance, and improve washability by preventing peeling during cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light-shielding film is formed on the outer peripheral portion of the lens, then anti-internal reflection performance is improved, but stress on the lens increases
Solution Approach 1:
The light-shielding film uses a composite material system consisting of a resin matrix, inorganic particles (such as silica or titania), and organic particles (such as rubber or silicone particles). This composite structure allows the film to achieve both high anti-internal reflection performance through the resin and inorganic particles, and reduced stress on the lens through the flexible organic particles that can accommodate thermal expansion and mechanical deformation.
2Stress or pressure
If the light-shielding film is made with low elastic modulus particles, then stress on the lens is reduced, but washability deteriorates
Solution Approach 1:
The organic particles in the light-shielding film have a differentiated structure with a surface layer portion and a center portion. The surface layer portion has a higher elastic modulus to provide wear resistance and maintain washability, while the center portion has a lower elastic modulus to reduce stress on the lens. This local quality differentiation allows the particles to simultaneously contribute to both requirements.
3Length of moving object
If the light-shielding film is formed on thinner lens edges, then the lens design is improved, but the film is more susceptible to stress and cracking
Solution Approach 1:
The light-shielding film uses organic particles with specifically controlled elastic modulus parameters. The particles have an elastic modulus in the range of 0.01 GPa to 7 GPa, with the surface layer portion having a higher elastic modulus than the center portion. This parameter control allows the film to maintain integrity on thinner lens edges by providing both flexibility to accommodate the thin geometry and sufficient strength to resist cracking under stress.
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 effectively reduces lens stress, enhances thermal shock resistance, and maintains high anti-internal reflection performance, ensuring the film remains intact during cleaning and extreme temperature exposure.
Implementation Method 1
an elastic modulus of the surface layer portion is higher than an elastic modulus of the center portion
Implementation Method 2
Providing the light-shielding film enables to reduce the reflected light from the inner surface which adversely affects the image to suppress the flare and the ghost
Implementation Method 3
the light-shielding film is a film formed on the surface of a substrate made of glass, plastic or the like, which is a main component of an optical element
Data Source
AI summary
A light-shielding film comprising a resin, an inorganic particle and an organic particle, wherein the organic particle is a core-shell particle which has a surface layer portion and a center portion, and an elastic modulus of the surface layer portion is higher than an elastic modulus of the center portion.