Laminate with Parallel Polarizers and Half Wave Plates for High Contrast Displays
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Solution Overview
Problem
Liquid crystal displays face size limitations due to polarizer width constraints and suffer from reduced contrast ratios due to light leakage and scattering, especially in horizontal alignment modes.
Innovation Solution
A liquid crystal display configuration with parallel absorption axes for upper and lower polarizers, incorporating a first half wave plate, a positive C plate, and a second half wave plate between the polarizers and the liquid crystal panel, optimized for horizontal alignment, to enhance contrast ratio and minimize size limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional polarizer configuration is used in liquid crystal displays, then the display can be manufactured with standard components, but the display size is limited by the width constraints of available polarizers
Solution Approach 1:
The invention divides the single polarizer function into multiple components: a first polarizer, a first half-wave plate, a second half-wave plate, and a second polarizer. This segmentation allows each component to be optimized independently and enables larger display areas by circumventing the width limitations of individual polarizer materials through the combined optical path of multiple elements arranged at specific angles.
2Ease of operation
If horizontal alignment liquid crystal mode is used, then the liquid crystal molecules can be easily controlled by voltage, but light leakage and scattering occur which reduces the contrast ratio
Solution Approach 1:
The invention introduces half-wave plates as intermediary optical elements between the polarizers and the liquid crystal layer. These half-wave plates act as mediators that rotate the polarization state of light in a controlled manner, compensating for the light leakage and scattering inherent in horizontal alignment modes, thereby improving contrast ratio while maintaining voltage control capabilities.
Solution Approach 2:
The invention creates a composite optical system combining multiple different optical materials (first polarizer, first half-wave plate, second half-wave plate, second polarizer) with distinct optical properties. This composite structure leverages the complementary characteristics of each material to achieve both ease of voltage control and high contrast ratio, overcoming the limitations of using a single material or simple configuration.
3Reliability
If multiple optical compensation films are added to improve contrast ratio, then the front contrast ratio increases, but the device complexity and number of layers increase
Solution Approach 1:
The half-wave plates in the invention serve multiple functions simultaneously: they rotate polarization states, compensate for light leakage, control scattering effects, and enable the parallel absorption axis configuration. This multi-functionality achieves high front contrast ratio without requiring multiple separate compensation films, thereby limiting the increase in device complexity despite the addition of essential optical elements.
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
This configuration reduces black luminance through side light scattering and minimizes light leakage at viewing angles, thereby increasing the front contrast ratio and addressing size limitations of polarizers.
Implementation Method 1
a first half wave plate, a positive C plate, and a second half wave plate are sequentially comprised between the upper polarizer and the liquid crystal panel
Implementation Method 2
a positive C plate provided between the first half wave plate and the second half wave plate
Implementation Method 3
liquid crystal molecules of a liquid crystal layer are driven by a difference in voltage applied to a common electrode and a pixel electrode
Implementation Method 4
the upper polarizer and the lower polarizer are provided such that absorption axes of the upper and lower polarizers are parallel to each other
Data Source
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AI summary
This application relates to a laminate comprising: a first half wave plate; a second half wave plate; and a positive C plate provided between the first half wave plate and the second half wave plate and a liquid crystal display comprising the same.