Ion Bombardment Treatment for Anti-Reflective Coating Adhesion
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Solution Overview
Problem
Existing optical articles with anti-reflective coatings face challenges in achieving both improved abrasion resistance and adhesion to the substrate, with underlayers enhancing abrasion resistance but potentially weakening the coating's adhesion and optical properties.
Innovation Solution
A method involving an ion bombardment treatment of the underlayer's surface before depositing a multilayer anti-reflective stack, combined with a silica-based underlayer and specific refractive index layers, enhances both abrasion resistance and adhesion properties without heating the substrate, and includes an antistatic layer for reduced static electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick underlayer is introduced to improve abrasion resistance, then abrasion resistance is improved, but adhesion to the substrate and optical properties deteriorate
Solution Approach 1:
The patent applies ion bombardment treatment to the underlayer surface before depositing the anti-reflective stack. This physical treatment modifies the surface parameters of the underlayer, creating a more reactive surface that enhances chemical bonding with the subsequent layers. The ion bombardment creates a micro-rough surface structure and increases surface energy, thereby improving adhesion without requiring the underlayer to be thinner, thus maintaining abrasion resistance.
Solution Approach 2:
The patent performs ion bombardment treatment as a preliminary step before depositing the multi-layer anti-reflective stack. This preliminary action prepares the underlayer surface in advance by removing organic contaminants, creating surface roughness, and increasing surface energy. This pre-treatment ensures that when the anti-reflective layers are deposited, they achieve optimal adhesion to the underlayer, resolving the contradiction between maintaining a thick underlayer for abrasion resistance and achieving good adhesion.
2Strength
If a thick underlayer is introduced to improve abrasion resistance, then abrasion resistance is improved, but optical properties deteriorate
Solution Approach 1:
The ion bombardment treatment modifies the surface parameters of the underlayer, creating a more reactive and cleaner surface. This allows the anti-reflective stack to be deposited with better optical quality directly on the treated underlayer surface. The treatment removes surface contaminants that would otherwise create optical defects, enabling the thick underlayer to maintain both abrasion resistance and optical properties.
3Reliability
If ion bombardment treatment is applied to the underlayer surface, then adhesion and abrasion resistance are improved, but process complexity increases
Solution Approach 1:
The patent merges the ion bombardment treatment step with the existing vacuum deposition process sequence. The ion bombardment is performed in the same vacuum chamber before the anti-reflective layers are deposited, combining surface preparation and layer deposition into a integrated process flow. This reduces the need for separate processing steps and additional equipment, thereby limiting the increase in process complexity while achieving improved adhesion.
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 method results in optical articles with improved abrasion resistance, enhanced adhesion of the anti-reflective coating to the substrate, and antistatic properties, maintaining transparency and optical quality while withstanding hot water treatment and mechanical stress.
Implementation Method 1
the exposed surface of said sub-coating is subjected to ion bombardment treatment prior to the deposition of said multi-layer stack
Implementation Method 2
deposit on a principal surface of the substrate a sub-coating having an exposed surface; deposit on said exposed surface of the sub-coating a multi-layer anti-reflective stack
Data Source
AI summary
The invention relates to a process for manufacturing an optical article having antireflection or reflective properties comprising a substrate having at least one main surface, which process comprises: a step of depositing a sublayer on a main surface of the substrate; a step of treating the sublayer by ion bombardment; and a step of depositing, on said sublayer, a multilayer stack comprising at least one layer having a high refractive index and at least one layer having a low refractive index. According to a preferred embodiment, the sublayer is deposited in a vacuum chamber with a gas introduced into the chamber during the deposition step.