Chemical Tempering of Glass Substrates for Optical Filters
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Solution Overview
Problem
Conventional glass substrates for optical filters, particularly thin substrates, face challenges with reduced strength and handling difficulties due to external stress and thermal expansion coefficient differences, limiting the thickness reduction of imaging devices and compromising durability.
Innovation Solution
A chemical-tempering process is employed to adjust the surface compressive stress value (CS) and depth of layer (DOL) of the glass substrate, achieving a compressive stress of 300 MPa or more and a depth of 10 μm or more, with a product value of 5000 MPa⋅μm or more to enhance the bending strength of the optical filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the glass substrate is reduced to make the optical filter thinner, then the overall thickness of the imaging device is reduced, but the bending strength of the glass substrate is greatly reduced making it difficult to handle and process
Solution Approach 1:
The glass substrate undergoes chemical tempering treatment before the deposition of optical filter layers. This preliminary action creates compressive stress in the surface layer and tensile stress in the inner layer, pre-strengthening the thin glass substrate to withstand subsequent processing and handling without breaking
Solution Approach 2:
The chemical tempering process changes the physical parameters of the glass substrate by controlling the depth of layer (DOL) and surface compressive stress (CS) through specific treatment conditions. This creates an optimized stress distribution that significantly increases bending strength while maintaining thin substrate thickness
2Strength
If chemical tempering is performed to increase surface compressive stress and depth of layer, then the bending strength of the glass substrate is increased, but the processing complexity and time required are increased
Solution Approach 1:
By optimizing the chemical tempering parameters (temperature, time, concentration), the process achieves the required bending strength with controlled and manageable processing conditions, balancing performance improvement with processing feasibility
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 significantly increases the bending strength and durability of the optical filter, ensuring high performance even in thin glass substrates, thereby addressing the limitations of conventional techniques and enabling thinner, more robust imaging devices.
Implementation Method 1
a glass substrate for optical filters is subjected to chemical tempering so that a surface compressive stress value (CS) and a depth of layer (DOL) of the glass substrate are adjusted
Implementation Method 2
chemical tempering process
Data Source
AI summary
The present invention provides a method of increasing the strength of a glass substrate for optical filters and a tempered-glass optical filter using a tempered glass substrate manufactured using the same, in which the glass substrate for optical filters is subjected to chemical tempering so that a compressive stress (CS) and a depth of layer (DOL) of the glass substrate are adjusted to increase the bending strength thereof.