Antireflection Film with Variable Side Component Ratios
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Solution Overview
Problem
Conventional antireflection films in optical pickup apparatuses suffer from poor environmental stability due to film stress caused by changes in temperature and humidity, leading to cracking and peeling, especially when using layers with the same composition for lower refractive index layers.
Innovation Solution
The optical element features an antireflection film with alternating layers of lower and higher refractive index, where at least two lower refractive index layers have the same main component but different side component content ratios, reducing film stress and enhancing environmental stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antireflection film is formed by laminating plural lower refractive index layers and plural higher refractive index layers to improve light stability, then the light transmittance and reflection prevention are improved, but the film stress caused by environmental changes leads to cracking and peeling
Solution Approach 1:
The patent applies local quality by making each lower refractive index layer have different composition characteristics. Specifically, the first lower refractive index layer contains a different side component content ratio compared to the second lower refractive index layer, creating local compositional variations that distribute stress differently across the film structure, preventing uniform stress concentration that leads to cracking and peeling.
Solution Approach 2:
The patent uses composite materials by combining layers with different refractive indices and compositional ratios. The alternating structure of higher and lower refractive index layers creates a composite film system where each layer contributes different optical and mechanical properties. The variation in side component content ratios within lower refractive index layers further diversifies the composite structure, enhancing overall film durability while maintaining optical performance.
2Ease of manufacture
If only layers with the same composition are used for the lower refractive index layer, then the manufacturing process is simplified, but repeated film stress causes cracking and peeling
Solution Approach 1:
The patent applies parameter changes by modifying the side component content ratio parameter in the lower refractive index layers. The first lower refractive index layer has a different side component content ratio compared to the second lower refractive index layer. This parameter variation allows the film to better accommodate environmental stress changes while maintaining manufacturability through controlled deposition processes.
3Adaptability or versatility
If the antireflection film uses alternating layers to prevent reflection for multiple wavelengths, then the balance in light transmitted amount is improved, but the film stress from temperature and humidity changes increases
Solution Approach 1:
The patent reduces film stress while maintaining multi-wavelength compatibility by introducing local compositional variations in the lower refractive index layers. The different side component content ratios in successive layers create local stress distribution patterns that prevent stress accumulation, allowing the alternating layer structure to maintain its optical performance across multiple wavelengths without suffering from excessive film 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
This configuration improves the environmental resistance of the optical element, preventing cracking and peeling, and maintaining favorable light transmittance across various wavelengths, making it suitable for use in optical pickup apparatuses handling different information recording media like CDs, DVDs, and Blu-ray discs.
Implementation Method 1
The antireflection film includes a plurality of lower refractive index layers and a plurality of higher refractive index layers. The plurality of lower refractive index layers and plurality of higher refractive index layers are layered alternately
Implementation Method 2
by forming the antireflection film of the optical element by laminating plural lower refractive index layers and plural higher refractive index layers, the light stability of the optical element is improved
Data Source
AI summary
The present invention provides an optical element including: a substrate; and an antireflection film formed on a surface of the substrate. The antireflection film includes a plurality of lower refractive index layers, and a plurality of higher refractive index layers which are layered alternately. Each of at least two of the plurality of lower refractive index layers comprises a same main component each other and comprises a side component with a different content ratio independently.