Printed Light Shielding Layer for Thin Curved Polarizing Plates
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Solution Overview
Problem
Conventional polarizing plates for optical displays, especially liquid crystal displays, require additional layers for light blocking and crack prevention, which increase thickness and complexity, while organic light emitting displays lack light blocking but suffer from external light reflection issues, leading to contrast deterioration.
Innovation Solution
A polarizing plate design incorporating a printed layer with a pigment, organic binder resin, reactive unsaturated compound, photopolymerization initiator, and solvent, which is thin enough to reduce overall display thickness and prevent cracking when applied to curved surfaces, and includes a curve securing portion to manage stress at edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional polarizing plate structure with additional bonding layers is used, then light shielding performance is improved, but the overall thickness of the optical display increases
Solution Approach 1:
The patent combines the printed layer and bonding layer into a single integrated structure. The printed layer serves dual functions: providing light shielding in non-display regions and acting as the bonding layer to adhere the polarizer to the polarizer protective film. This eliminates the need for separate bonding layers, thereby reducing overall thickness while maintaining light shielding performance.
Solution Approach 2:
The printed layer is designed to perform multiple functions simultaneously: (1) light shielding to prevent viewing of non-display region elements, (2) bonding to adhere the polarizer to the protective film, and (3) crack prevention through its elastic modulus properties. This multi-functionality reduces the number of separate layers needed, thereby reducing overall thickness.
2Object-affected harmful factors
If a printed layer is applied to curved edges of non-display regions, then light shielding is improved, but cracks may generate at the curved edges
Solution Approach 1:
The patent controls the elastic modulus of the printed layer to be within a specific range (1×10^8 to 1×10^10 dyne/cm²). This parameter optimization allows the printed layer to be flexible enough to conform to curved edges without cracking, while still maintaining sufficient rigidity to provide effective light shielding.
Solution Approach 2:
The printed layer is formulated as a composite material containing specific components (pigment, binder resin, reactive unsaturated compound, photopolymerization initiator, and solvent) in controlled proportions. This composite structure provides both the light shielding capability through pigment dispersion and the mechanical flexibility through the polymer matrix, enabling crack-free application on curved edges.
3Object-affected harmful factors
If the printed layer thickness is increased, then light shielding performance is improved, but the overall display thickness increases
Solution Approach 1:
The printed layer uses a composite formulation with high pigment concentration (1-50 wt%) dispersed in a polymer matrix. This composite structure provides high light shielding effectiveness in a thin layer because the pigment particles efficiently block light transmission. The thin layer thickness (1-10 μm) is sufficient to shield non-display regions while minimizing impact on overall display thickness.
Solution Approach 2:
The printed layer is applied selectively only in the non-display region surrounding the display area, rather than across the entire polarizing plate. This localized application provides light shielding where needed while keeping the display region thickness minimal, thereby reducing the overall impact on display thickness.
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 effectively shields non-display regions, reduces optical display thickness, and prevents cracking on curved edges, enhancing both the aesthetic appeal and durability of the polarizing plate while maintaining excellent light shielding properties.
Implementation Method 1
a photopolymerization initiator
Data Source
AI summary
Provided are a polarizing plate, a method of manufacturing same, and a display device including same. The polarizing plate comprises: a polarizer; a polarizer protective film disposed on at least one surface of the polarizer; an adhesive layer interposed between the polarizer and the polarizer protective film; and a print layer interposed between the polarizer and the polarizer protective film, and formed on at least a portion of the edge of the adhesive layer. The print layer comprises: a pigment; an organic resin binder; a reactive unsaturated compound; a photopolymerization initiator; and a solvent.