Dual-Layer Polarizer for High-Contrast ADS Displays
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Solution Overview
Problem
Advanced Super Dimension Switch (ADS) display technology is limited by a low contrast ratio, which restricts its application in high-end TV products due to the limitations of its production process, achieving only about 1200 to 1800 contrast ratio.
Innovation Solution
A display apparatus is designed with a stacked configuration of polarizers and liquid crystal panels, where the second polarizer includes two protective layers with specific optical path difference compensation values, and the first and third polarizers also have similar structures, enhancing the contrast ratio by controlling the in-plane and thickness direction optical path differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If ADS display technology is used, then wide viewing angle and high transmittance are achieved, but contrast ratio is limited to 1200-1800
Solution Approach 1:
The patent divides the liquid crystal display into two separate liquid crystal panels (first and second liquid crystal panels) with different liquid crystal materials and optical characteristics. This segmentation allows each panel to contribute different optical functions, with the first panel providing wide viewing angle and high transmittance, while the second panel compensates for contrast ratio limitations, achieving overall contrast ratio exceeding 150,000.
Solution Approach 2:
The patent employs composite material strategy by using two different liquid crystal materials in separate panels - the first liquid crystal panel uses a material optimized for wide viewing angle and high transmittance, while the second liquid crystal panel uses a material with different optical properties to compensate contrast ratio. The combination of these two liquid crystal materials achieves performance that neither material could achieve alone.
2Ease of manufacture
If conventional single liquid crystal panel is used, then manufacturing process is simple, but contrast ratio cannot exceed 1800
Solution Approach 1:
Instead of attempting to achieve high contrast ratio through complex modifications of a single liquid crystal panel, the patent segments the display system into two simpler liquid crystal panels with different optimized functions. Each panel can be manufactured using relatively simple processes, but their combination achieves the high contrast ratio that would be extremely difficult to achieve in a single panel.
Solution Approach 2:
The patent transitions from a single-panel two-dimensional optimization problem to a multi-panel three-dimensional solution space. By adding the dimension of multiple panels with different orientations and optical properties, the system achieves high contrast ratio without requiring extremely complex manufacturing processes within each individual panel.
3Ease of manufacture
If protective layers with high optical path difference compensation are used, then manufacturing flexibility is improved, but polarization control precision deteriorates
Solution Approach 1:
The patent carefully selects and controls the optical path difference compensation parameters of the protective layers. By setting specific numerical ranges for in-plane optical path difference compensation value (Ro < 100 nm) and thickness direction optical path difference compensation value (Rth < 1000 nm), the patent achieves a balance between manufacturing flexibility and polarization control precision, ensuring that the protective layers do not significantly degrade the polarization state while allowing for practical manufacturing variations.
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 significantly improves the contrast ratio to over 150,000, enabling the display apparatus to meet the requirements for high-end TV products by effectively managing the polarization of light through the protective layers and polarizing layers.
Implementation Method 1
an in-plane optical path difference compensation value Ro of the protective layer close to the first liquid crystal panel among the two protective layers of the second polarizer is less than 100 nm, and an optical path difference compensation value Rth in a thickness direction is less than 1000 nm
Implementation Method 2
the second polarizer includes two protective layers, and a polarizing layer positioned between the two protective layers
Data Source
AI summary
A display apparatus includes a first polarizer, a first liquid crystal panel, a second polarizer, a second liquid crystal panel and a third polarizer which are sequentially stacked, wherein the second polarizer includes two protective layers, and a polarizing layer positioned between the two protective layers.