Optical Film Contrast Improving Layer for LCD Reflectance Reduction
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Solution Overview
Problem
Liquid crystal displays (LCDs) face challenges in maintaining high contrast ratios and reducing reflectance, especially when viewed from the side, due to optical patterns that obstruct light and increase external light reflectance, leading to decreased front contrast and increased brightness in black mode.
Innovation Solution
An optical film with a protective layer and a contrast improving layer, where the contrast improving layer consists of a first resin layer with embossed optical patterns and a second resin layer containing a metal complex salt dye or organic black dye, is used. The second resin layer has a lower refractive index than the first, and the embossed patterns are designed to optimize light diffusion and reduce reflectance, improving front contrast and viewing angles without affecting side contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical patterns are used to improve side contrast ratio, then side contrast ratio is improved, but front contrast ratio deteriorates and reflectance increases
Solution Approach 1:
The optical film is divided into multiple functional layers: a first resin layer containing embossed optical patterns for side contrast improvement, and a second resin layer containing black dyes for reflectance reduction. This segmentation allows each layer to perform its specific function without interfering with the other, resolving the contradiction between side contrast enhancement and reflectance control
Solution Approach 2:
Different regions of the optical film are assigned different properties: the first resin layer has high refractive index and optical patterns for light manipulation at oblique angles, while the second resin layer has light-absorbing black dyes for reducing reflectance. This local differentiation of material properties enables simultaneous achievement of improved side contrast and reduced reflectance
2Measurement precision
If optical patterns obstruct light to improve side contrast, then side contrast is improved, but front brightness and front contrast ratio deteriorate
Solution Approach 1:
The optical film separates light manipulation functions (embossed patterns in first resin layer) from light absorption functions (black dyes in second resin layer), allowing the patterns to improve side contrast while the dye layer compensates for front brightness loss by selectively absorbing reflected light
Solution Approach 2:
The black dyes in the second resin layer convert the harmful effect of light obstruction (reduced front brightness) into a beneficial effect by absorbing stray and reflected light, thereby improving front contrast ratio without compromising the side contrast improvement achieved by the embossed patterns
3Adaptability or versatility
If optical patterns are embossed to improve viewing angle, then viewing angle is enhanced, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into distinct steps: forming embossed patterns in the first resin layer, then forming the second resin layer containing dyes. This segmentation allows each layer to be optimized and manufactured independently, reducing overall manufacturing complexity while achieving enhanced viewing angle through the embossed patterns
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 optical film enhances front contrast ratio, reduces side surface brightness in black mode, and minimizes color shifting, while also reducing overall reflectance and power consumption by optimizing light diffusion and light transmission, thereby improving the viewing experience and efficiency of LCDs.
Implementation Method 1
An optical film includes a low refractivity layer and a high refractivity layer, and improves a side contrast ratio of an optical display using optical patterns
Implementation Method 2
the second resin layer includes a metal complex salt dye and/or an organic black dye
Data Source
AI summary
An optical film, a polarizing plate including the same, and a liquid crystal display including the same are provided. The optical film includes a protective layer and a contrast improving layer, wherein the contrast improving layer includes a second resin layer that is stacked from the protective layer, and a first resin layer facing the second resin layer.