Glass Substrate Unevenness Detection via Photoelasticity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for detecting unevenness in glass substrates for LCD devices are unreliable and prone to human error, particularly when using non-contact optical methods that rely on visual inspection, leading to reduced production efficiency and increased production costs due to the small height of protrusions causing display quality degradation.
Innovation Solution
A detecting device and method utilizing a light source, polarizer, and standard cell with a glass substrate attached to one of its surfaces, employing polarized light and analyzing retardation values to determine the presence and type of unevenness, allowing for accurate detection and database storage of results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If visual inspection methods are used to detect unevenness, then the detection process is simple, but the reliability and precision of detection deteriorate due to human error and inability to detect small protrusions
Solution Approach 1:
The patent replaces visual inspection (mechanical/optical observation) with a photoelasticity-based optical measurement system. The system uses polarized light passing through a liquid crystal layer to detect unevenness, converting physical deformation into optical signal changes that can be precisely measured and analyzed, thereby eliminating human error while maintaining operational simplicity.
Solution Approach 2:
The patent changes the detection parameter from visual appearance to optical retardation values. By measuring the change in polarization state of light passing through the liquid crystal layer, the system can detect extremely small protrusions (as small as 10 nm) that are invisible to the human eye, significantly improving measurement precision.
2Measurement precision
If contact methods are used to detect unevenness, then measurement precision improves, but the glass substrate is damaged and production efficiency deteriorates
Solution Approach 1:
The patent replaces contact-based mechanical measurement methods with a non-contact optical measurement system based on photoelasticity. The system uses polarized light to detect surface unevenness without physically touching the glass substrate, eliminating damage while maintaining high measurement precision, thus preserving production efficiency.
Solution Approach 2:
The patent introduces a liquid crystal layer as an intermediary between the light source and the glass substrate. This liquid crystal layer amplifies the optical effect of small surface unevenness, enabling precise detection without direct contact with the substrate, thereby avoiding damage while achieving high measurement precision.
3Productivity
If non-contact optical methods are used to detect unevenness, then production efficiency improves, but measurement precision deteriorates due to inability to detect small protrusions
Solution Approach 1:
The patent changes the detection parameter from visual appearance to optical retardation values by utilizing the photoelastic effect. This parameter transformation enables the detection of extremely small protrusions (as small as 10 nm) through precise measurement of polarization state changes, significantly improving measurement precision while maintaining non-contact operation and high production efficiency.
Solution Approach 2:
The patent introduces a liquid crystal layer as an intermediary that amplifies the optical effect of small surface unevenness. The liquid crystal's birefringent properties convert minute physical deformations into measurable optical signal changes, enabling high-precision detection of small protrusions without contact, thus maintaining both high productivity and measurement precision.
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 enhances the reliability of detecting small unevenness on glass substrates, enabling precise detection of both streak and cord type unevenness with heights as low as 10 nm, improving production efficiency and reducing human error in LCD manufacturing.
Implementation Method 1
a liquid crystal layer 15 between the array and color filter substrates 10 and 5
Implementation Method 2
employing polarized light and analyzing retardation values
Data Source
AI summary
A detecting device of unevenness of a glass substrate includes a light source emitting a light; a polarizer polarizing the light; a standard cell including opposing outer surfaces, the glass substrate attached to one of the opposing outer surfaces, the polarized light passing through the standard cell and the glass substrate; an analyzer detecting and analyzing the light passing through the standard cell and the glass substrate.