Optical Element Light-Shielding Film Alkali Resistance Coating
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Solution Overview
Problem
Optical elements, such as lenses, experience color change and development of white spots when used under high-temperature and high-humidity conditions, especially after washing with an alkaline aqueous solution, due to the instability of light-shielding films.
Innovation Solution
The optical element features a light-shielding film with a binder resin, a coloring agent, and inorganic fine particles, along with a protective coating comprising a cured mixture of melamine or benzoguanamine resin and phenolic resin, which enhances waterproofness and alkali resistance, preventing color change and white spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light-shielding film with dye is used on the optical element, then the optical element can prevent flares and ghosts, but the light-shielding film changes color and develops white spots when used under high-temperature and high-humidity conditions, especially after washing with alkaline aqueous solution
Solution Approach 1:
A protective coating layer is introduced as an intermediary between the light-shielding film and the external environment (alkaline solutions and humidity). This coating acts as a barrier that prevents direct contact between the dye-containing light-shielding film and harmful external factors, thereby preventing color change and white spot formation while maintaining the flare prevention function
Solution Approach 2:
The optical element structure is transformed into a composite material system consisting of multiple layers: the light-shielding film layer containing dye, and the protective coating layer. This composite structure combines the light-shielding function of the dye-containing film with the protective function of the coating, resolving the contradiction between flare prevention and appearance stability
2Ease of operation
If the optical element is washed with alkaline aqueous solution after forming the light-shielding film and protective coating, then cleaning effectiveness is improved, but the light-shielding film develops white spots and color changes
Solution Approach 1:
The protective coating serves as an intermediary barrier that allows the light-shielding film to be exposed to alkaline cleaning solutions without direct harmful interaction. The coating withstands the alkaline environment and prevents it from penetrating to the dye-containing film, enabling effective cleaning while maintaining film stability
Solution Approach 2:
The protective coating is applied in advance before the cleaning process, providing a cushioning protective layer that pre-shields the light-shielding film from the damaging effects of alkaline solutions. This prior protection prevents the white spot formation and color changes that would otherwise occur during cleaning
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 maintains the optical element's appearance over a long period under high-temperature and high-humidity conditions, even after exposure to alkaline solutions, by ensuring the light-shielding film's stability and adhesion.
Implementation Method 1
this protective coating prevents dyes in a light-shielding film, such as a black dye, from dissolving out of the film
Implementation Method 2
a protective coating comprising a cured mixture of melamine or benzoguanamine resin and phenolic resin, which enhances waterproofness and alkali resistance
Data Source
Figure 1
Figure 2A~2E
AI summary
An optical element (1) having a substrate (2) and a light-shielding film (3) on part of an outer portion of the substrate (2) further contains a coating (4) on the light-shielding film (3), the coating (4) containing a cured mixture of melamine or benzoguanamine resin, and a phenolic resin, in proportions by mass of 1:5 to 7:5.