Wire-Grid Polarizing Plate Using Metal Semiconductor Layers
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Solution Overview
Problem
Conventional polarizing plates for liquid crystal display devices face challenges in achieving high optical performance, durability, and wideband polarizing properties due to limitations in material choice, manufacturing processes, and reflectance issues, particularly when exposed to visible light and high luminous energy sources.
Innovation Solution
A polarizing plate comprising a transparent substrate with a metal-containing semiconductor layer as an absorbing layer and a reflective layer, both structured as one-dimensional lattice wire-grid patterns with pitches smaller than the wavelength of visible light, layered in specific orders to enhance light absorption and reduce reflectance, thereby achieving improved optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a film-based polarizing plate is used, then the manufacturing process is simple, but the mechanical strength is insufficient and heat-resisting property is limited
Solution Approach 1:
The patent uses a composite structure combining a glass substrate with a wire grid pattern formed by depositing metal layers (silver and aluminum) in alternating orientations. This composite approach provides both the mechanical strength of glass and the polarizing function of the metal wire grid, resolving the contradiction between ease of manufacture and mechanical strength.
2Ease of manufacture
If a film-based polarizing plate is used, then the manufacturing process is simple, but the heat-resisting property is limited
Solution Approach 1:
The patent employs a glass substrate which inherently possesses high heat resistance, combined with a wire grid polarizing structure. This composite material approach maintains the simplicity of the manufacturing process while dramatically improving the heat-resisting property compared to organic film-based polarizing plates.
3Ease of manufacture
If silver particles are used for island particles, then the polarizing plate can be manufactured, but it does not cover visible light range
Solution Approach 1:
The patent changes the material parameter from pure silver to alternating layers of silver and aluminum. Aluminum has different optical properties with plasma resonance absorption in the visible range, while silver provides absorption in the infrared range. This parameter change enables the polarizing plate to cover both visible and infrared wavelengths.
4Reliability
If a wire-grid structure with metal layers is used, then the optical performance is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the metal layer into alternating silver and aluminum layers deposited at different orientations (0度和90度). This segmentation allows each layer to contribute differently to the polarizing effect, improving optical performance while maintaining a systematic manufacturing approach that doesn't excessively increase complexity.
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 provides a polarizing plate with enhanced optical performance, reduced reflectance, and increased durability, suitable for applications in liquid crystal projectors and other devices requiring high light-fastness and wideband polarizing capabilities.
Implementation Method 1
The principle of this utilizes plasma resonance absorption of island particles. Particularly, it utilizes light absorption by surface plasma resonance occurring when light enters into the island particles of precious metals or transition metals
Implementation Method 2
an absorbing layer having at least a metal-containing semiconductor layer, the absorbing layer being arranged as a one-dimensional lattice shaped wire-grid structure having a pitch smaller than the wavelength of the light in the used bandwidth
Data Source
AI summary
A polarizing plate having an excellent optical property and a method of manufacturing the same. The polarizing plate includes: a transparent substrate transmitting light in a used bandwidth; an absorbing layer having at least a metal-containing semiconductor layer containing a metal, the absorbing layer being arranged as a one-dimensional lattice shaped wire-grid structure having a pitch smaller than the wavelength of the light in the used bandwidth; a dielectric layer arranged as a one-dimensional lattice shaped wire-grid structure having a pitch smaller than the wavelength of light in the used bandwidth; and a reflective layer arranged as a one-dimensional lattice shaped wire-grid structure having a pitch smaller than the wavelength of light in the used bandwidth, wherein the absorbing layer, the dielectric layer and the reflective layer are layered on the transparent substrate in this or reversed order.