Optical Compensation Device with Tilted Negative C-Plate
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Solution Overview
Problem
Liquid crystal display units in projection systems face challenges in achieving high luminance and contrast ratio due to residual retardation issues, which existing optical compensators fail to adequately address, particularly in vertical alignment mode, leading to light loss and decreased performance.
Innovation Solution
The implementation of an optical compensation device with a first and second underlayer, each featuring structures with different inclination angles and alternately stacked refractive index films, forming a negative C-plate with a tilted optical axis, where the array pitch of these structures is smaller than the visible light wavelength, reducing diffraction and light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional optical compensators are used to compensate residual retardation, then the liquid crystal display unit can achieve high luminance and contrast ratio, but light loss occurs due to diffraction effects
Solution Approach 1:
The optical compensation device is divided into multiple functional layers: a first underlayer with first structures, a first multilayered film, a second underlayer with second structures, and a second multilayered film. Each layer performs a specific function in compensating residual retardation while minimizing diffraction effects.
Solution Approach 2:
The first and second structures in the underlayers are designed with specific local geometric characteristics (different inclination angles) to create localized optical effects that collectively compensate residual retardation without causing significant diffraction loss.
2Reliability
If existing optical compensators are implemented, then residual retardation compensation is achieved, but the device complexity increases
Solution Approach 1:
Multiple functional elements (underlayers with structures and multilayered films) are merged into a single integrated optical compensation device that performs both residual retardation compensation and diffraction reduction functions simultaneously.
Solution Approach 2:
The device combines different material structures (underlayers with specific geometric structures and multilayered films with alternating refractive indices) to achieve superior optical compensation performance that cannot be obtained with single-material approaches.
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 effectively compensates for residual retardation, enhancing luminance and contrast ratio while minimizing light loss and material degradation, thus improving the overall performance of liquid crystal display units in projection systems.
Implementation Method 1
a first multilayered film provided on the first underlayer, and including at least two refractive index films that are alternately stacked and have refractive indices different from each other
Implementation Method 2
An array pitch of the plurality of the structures in each of the first underlayer and the second underlayer is smaller than a wavelength of visible light, which suppresses an influence of diffraction on the optical compensation device and reduces light loss
Data Source
AI summary
An optical compensation device used in a liquid crystal display unit of the present invention includes: a first underlayer (332A) including a plurality of structures (332A1) that each includes at least two surfaces having inclination angles different from each other; a first multilayered film (332B) provided on the first underlayer (332A), and including at least two refractive index films (332b1 and, 332b2) that are alternately stacked and have refractive indices different from each other: a second underlayer (332C) including a plurality of structures (332C1) that each includes at least two surfaces having inclination angles different from each other, and being opposed to the first underlayer (332A) with the first multilayered film (332B) interposed therebetween; and a second multilayered film (332D) provided on the second underlayer (332C), and including at least two refractive index films (332d1 and 332d2) that are alternately stacked and have refractive indices different from each other, and an array pitch of the plurality of the structures (332A1 or 332C1) in each of the first underlayer (332A) and the second underlayer (332C) is smaller than a wavelength of visible light.