Projection Display Wire-Grid PBS Disclination Control
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Solution Overview
Problem
Projection type display devices using vertically-aligned reflection type liquid crystal display devices with wire-grid polarizing beam splitters face challenges in maintaining high contrast while minimizing disclination, which can lead to color shifts and image quality deterioration, especially under oblique light incidence.
Innovation Solution
The implementation of a projection type display device with a reflection type liquid crystal display device that includes a first and second twist type liquid crystal display device, where liquid crystal molecules on one substrate are aligned clockwise and counterclockwise relative to a reference line, and the wire-grid polarization beam splitter is inclined to minimize disclination and maintain high contrast by adjusting the reference line's vector within specific angular ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a vertically-aligned reflection type liquid crystal display device with a wire-grid polarizing beam splitter is used, then high contrast display images can be achieved, but disclination occurs leading to color shifts and image quality deterioration
Solution Approach 1:
The invention changes the alignment parameters of liquid crystal molecules by introducing a twist angle between the alignment directions at the first and second substrates. Specifically, the alignment direction at the second substrate is rotated by a twist angle of 90 degrees or more (up to 180 degrees) relative to the first substrate, which modifies the liquid crystal orientation profile and eliminates disclination while preserving high contrast through the wire-grid polarizing beam splitter configuration
2Illumination intensity
If liquid crystal molecules are vertically aligned to achieve high contrast, then display brightness is improved, but disclination causes color shifts and image deterioration
Solution Approach 1:
The invention applies preliminary twisting action to the liquid crystal alignment during the manufacturing process. By pre-establishing a twist angle between 90 and 180 degrees between the alignment directions at the two substrates before operation, the liquid crystal molecules are pre-configured to avoid disclination formation during voltage application, thereby preventing color shifts and image deterioration while maintaining brightness
3Use of energy by moving object
If the wire-grid polarizing beam splitter is arranged at a 45-degree inclination, then light polarization efficiency is improved, but disclination effects are exacerbated
Solution Approach 1:
The invention introduces asymmetry in the liquid crystal alignment configuration by applying a twist angle between the alignment directions at the first and second substrates. This asymmetric twist configuration (90-180 degrees) modifies the interaction between the liquid crystal layer and the wire-grid polarizing beam splitter, distributing the optical path differences in a way that reduces color shifts while maintaining polarization efficiency at the 45-degree inclination
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 minimizes disclination and ensures high contrast images by aligning liquid crystal molecules appropriately, reducing color shifts and enhancing image quality across various viewing angles.
Implementation Method 1
a wire grid polarizing beam splitter (referred to as 'WG-PBS' hereinafter)... The P polarization component of the illumination light transmitted through the WG-PBS 2 is then incident on the LCD device 1
Implementation Method 2
a liquid crystal layer 13 enclosed in a gap between the substrate 11 and the substrate 12... the liquid crystal layer utilizes the reflection type liquid crystal display device of vertically-aligned liquid crystals
Implementation Method 3
another substrate opposed to the former substrate and having reflecting electrodes... The modulated light reflected by the LCD device 1 returns to the WG-PBS 2
Data Source
Figure 1
Figure 2~3
Figure 4~5A
AI summary
A projection type display device is provided to display high quality images. In the device, a WB-PBSW 2 is inclined to liquid crystal display devices 1r, 1b, 1g and has wire grids 2a parallel with a first substrate 11. One of directions of projection lines obtained by projecting the wire grids 2a on a second substrate 12 vertically, the one direction being directed to a direction where one extension surface of the polarization spectroscopic surface intersects with another extension surface of the second substrate when the one direction is turned in the counterclockwise direction by 90°, is defmed as X-axis. If the liquid crystal display devices 1r, 1b, 1g are a type of first twist (normal twist), device reference line vectors are located at 225° ± 10° in the counterclockwise direction in view from the first substrate 11. In case of a second twist (reverse twist) type, the device reference line vectors are located at 315° ± 10° in the counterclockwise direction in view from the first substrate 11.