Polarizing Plate Mura Inspection With Multi-Angle Polarization
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Solution Overview
Problem
Existing methods struggle to easily identify liquid crystal stains on polarization plates, particularly when protective films are attached, which affect the visibility and quality of organic light emitting displays.
Innovation Solution
A liquid crystal stain inspection device and method utilizing a surface light source, first and second polarization members, and an inspection source, where light is emitted, transmitted through these components, and analyzed for visibility differences to detect stains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a general inspection method is used to detect liquid crystal stains on polarization plates, then the inspection process is simple, but the stains are difficult to identify especially when protective films are attached
Solution Approach 1:
The inspection device dynamically changes the polarization state of light by rotating the polarization plate to different angles (0°, 45°, 90°, 135°) relative to the fixed polarizer. This dynamic adjustment allows the system to detect liquid crystal stains at optimal polarization orientations, transforming a static inspection into a dynamic multi-angle detection process that overcomes the limitation of single-angle general inspection methods
Solution Approach 2:
The system changes the polarization angle parameter by rotating the polarization plate to four distinct angles (0°, 45°, 90°, 135°). This parameter variation enables the detection of liquid crystal stains that may be invisible at certain angles, as the stains exhibit different optical properties depending on the polarization orientation relative to the polarizer
2Reliability
If protective films and release films are attached to the polarization plate, then the polarization plate is protected during manufacturing and handling, but liquid crystal stains become more difficult to identify
Solution Approach 1:
The inspection device detects liquid crystal stains by analyzing changes in light intensity and polarization state that manifest as visual contrasts or 'color' differences in the optical signal. When light passes through the polarizer, polarization plate, and protective films, stains cause measurable deviations in the transmitted light intensity at different polarization angles, creating detectable optical signatures that distinguish stains from the protected film structure
3Reliability
If a quarter wave plate with liquid crystal coating is used to rotate light phase, then the polarization plate functions correctly to block reflected light, but liquid crystal stains are generated due to thickness deviation or pressing
Solution Approach 1:
The inspection device performs preliminary detection of liquid crystal stains on the quarter wave plate before the polarization plate is fully assembled and shipped. By detecting stains at the manufacturing stage using the multi-angle polarization method, defective plates can be identified and removed before they cause display issues, preventing the propagation of harmful stains to final products
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
Enables easy and effective detection of liquid crystal stains with improved visibility, enhancing the quality of organic light emitting displays by identifying stains before protective films are applied.
Implementation Method 1
a first polarization member (200) disposed such that light is applied from the surface light source
Implementation Method 2
the first polarization member has an absorption axis perpendicular to the polarizer of the polarization plate
Implementation Method 3
a quarter wave plate (QWP) that rotates the phase of light 1/4 turn
Implementation Method 4
the polarization plate comprises a quarter wave plate (QWP) that rotates the phase of light 1/4 turn
Implementation Method 5
the polarization plate comprises a polarizer and a quarter wave plate including a liquid crystal film sequentially
Implementation Method 6
the light transmitted through the first polarization member is applied to the quarter wave plate of the polarization plate
Implementation Method 7
a second polarization member disposed such that the light reflected from the polarization plate is applied
Implementation Method 8
the second polarization member may have an absorption axis parallel to the polarizer of the polarization plate
Implementation Method 9
the quarter wave plate may be implemented as a polymer film or a liquid crystal coating
Implementation Method 10
liquid crystal stains, the color sense whose looks different upon reflection, were caused by the thickness deviation or pressing of the liquid crystal layer
Data Source
Figure 1~2
AI summary
The present application relates to a liquid crystal stain inspection device of a polarization plate and a liquid crystal stain inspection method of a polarization plate. The present application can easily inspect liquid crystal stains generated on a polarization plate with excellent visibility.