Polarizing Plate with Patterned Contrast Layer for LCD
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Solution Overview
Problem
Liquid crystal display devices face challenges in maintaining high front contrast ratio while improving side contrast ratio and preventing degradation of black visual sensitivity and appearance, especially when exposed to external light such as sunlight or lighting.
Innovation Solution
A polarizing plate comprising a polarizing film, a contrast ratio enhancing layer with a specific patterned structure, and an antireflection film, where the antireflection film has a minimum reflectance of 0.45% or less, and the contrast ratio enhancing layer includes a first and second resin layer with optical patterns, optimizing the reflectance slope and luminous reflectance to reduce color dispersion and improve visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional polarizing plate is used to achieve good front contrast ratio, then the front contrast ratio is improved, but the side contrast ratio remains relatively low and black visual sensitivity deteriorates when external light is irradiated
Solution Approach 1:
The polarizing plate is divided into multiple functional layers: a polarizing film for front contrast, a contrast ratio enhancing layer with light scattering particles for side contrast improvement, and an antireflection film with specific reflectance characteristics (0.45% or less) to prevent external light interference. This segmentation allows each layer to address specific issues independently while working together to resolve the overall contradiction.
Solution Approach 2:
The contrast ratio enhancing layer acts as an intermediary between the polarizing film and the external environment. It contains light scattering particles that diffuse reflected light and reduce the impact of external light sources, thereby protecting the black visual sensitivity while maintaining the front contrast ratio provided by the polarizing film.
2Adaptability or versatility
If the side contrast ratio is increased to improve visibility, then the side viewing angle is improved, but the front contrast ratio may be reduced
Solution Approach 1:
The contrast ratio enhancing layer introduces local quality variations through light scattering particles with specific size distributions and concentrations. These particles are strategically positioned to scatter light primarily in side viewing directions, enhancing side contrast ratio and viewing angle while having minimal impact on the front contrast ratio maintained by the polarizing film.
3Object-affected harmful factors
If external light is blocked to improve black visual sensitivity, then the appearance under sunlight or lighting is improved, but the overall light transmission and visibility may be reduced
Solution Approach 1:
The antireflection film is designed with specific optical parameters, particularly a minimum reflectance of 0.45% or less across the visible spectrum. This parameter optimization allows the film to minimize reflected light from external sources (improving appearance and black visual sensitivity) while maintaining high light transmission for visibility during device operation.
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 black visual sensitivity and appearance by preventing rainbow mura and unevenness, while improving visibility and side contrast ratio, even when external light is irradiated, without affecting the device's performance during operation or non-operation states.
Implementation Method 1
an antireflection film, which are sequentially laminated on the polarizing film in this order, the antireflection film having a minimum reflectance of 0.45% or less
Implementation Method 2
the contrast ratio enhancing layer includes a first resin layer and a second resin layer facing the first resin layer, wherein the second resin layer includes a patterned portion including optical patterns
Implementation Method 3
the patterned portion including optical patterns and a flat portion formed between the optical patterns
Implementation Method 4
A polarizing plate may include a polarizing film, a contrast ratio enhancing layer, and an antireflection film
Data Source
AI summary
Provided are a polarizing plate and a liquid crystal display device including same, the polarizing plate including a polarization film, a contrast-improving layer, and an anti-reflection film that are sequentially laminated. The minimum reflectance of the anti-reflection film is no greater than 0.45%. The anti-reflection film has a first substrate layer, a high-refraction layer and a low-refraction layer that are laminated in order from the contrast-improving layer. The contrast-improving layer includes a first resin layer and a second resin layer facing the first resin layer. The second resin layer is provided with a pattern part having optical patterns and a flat part between the optical patterns. The pattern part satisfies Equation 1 and the optical patterns have a base angle (θ) of 60° to 90°. The slope of the reflectance of the polarization plate in Equation 2 is no greater than 0.3.