Orthogonal Liquid Crystal Alignment for Projection Display Disclination
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Solution Overview
Problem
Projection display devices using liquid crystal panels often suffer from disclination, which leads to image quality deterioration, such as coloring, tailing, and light leakage, especially when reflective liquid crystal panels are used, due to misalignment of liquid crystal molecules caused by potential differences between neighboring pixels.
Innovation Solution
A projection display device is designed with multiple reflective liquid crystal panels and polarizers, where the liquid crystal molecules are pre-tilted and aligned orthogonally to each other, and polarizers are strategically placed to manage the polarization states of light, ensuring that the alignment direction of one panel is orthogonal to the other, and combining optical systems are used to align the light paths effectively, thereby minimizing disclination effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If reflective liquid crystal panels are used to achieve higher definition, smaller size, and higher luminance, then projection performance is improved, but disclination occurs causing image quality deterioration
Solution Approach 1:
The patent applies asymmetry by setting different alignment directions for liquid crystal panels displaying different colors. Specifically, the alignment direction for blue color is set at 45 degrees relative to the pixel arrangement, while green and red colors are set at 135 degrees. This asymmetric configuration prevents disclination by ensuring that liquid crystal molecules in adjacent pixels do not experience conflicting alignment forces, thereby maintaining image quality while preserving the high luminance and definition benefits of reflective liquid crystal panels.
2Illumination intensity
If voltage difference between neighboring pixels is increased to increase luminance difference, then image contrast is improved, but transverse electric field causes coloring and light leakage
Solution Approach 1:
The patent applies local quality by optimizing the alignment direction of liquid crystal molecules specifically for blue color pixels at 45 degrees, while green and red pixels use 135 degrees. This localized differentiation in alignment configuration allows each color channel to be independently optimized, preventing transverse electric field-induced disclination in high-contrast regions while maintaining the ability to achieve high luminance differences through voltage control.
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 suppresses image quality deterioration caused by disclination, enabling the display of high-contrast images by aligning the liquid crystal molecules and managing polarization states to match light paths, resulting in improved image projection quality.
Implementation Method 1
a liquid crystal layer including a liquid crystal which has a negative dielectric anisotropy
Implementation Method 2
to perform light modulation of the color light based on image data
Implementation Method 3
polarizers which are arranged in the optical paths of the plurality of color light respectively, to be inclined to the optical path of the color light incident to the reflective liquid crystal panel, and pass through the color light in a first polarization state incident to the reflective liquid crystal panel, and reflect the color light in a second polarization state from the reflective liquid crystal panel
Implementation Method 4
a combining optical system which combines the plurality of color light, which are modulated by the reflective liquid crystal panels and are reflected by the polarizers, to generate combined light
Data Source
AI summary
A projection display device includes a plurality of reflective liquid crystal panels, a plurality of polarizers, and a combining optical system. The combining optical system includes a first incident surface to which first color light emitted from a first reflective liquid crystal panel and reflected by a combining surface of the combining optical system is incident and a second incident surface to which second color light emitted from a second reflective liquid crystal panel and passing through the combining surface is incident. The polarizes include a first polarizer, which reflects the first color light to the first incident surface, and a second polarizer which reflects the second color light to the second incident surface. An alignment direction of the liquid crystal of the first reflective liquid crystal panel is orthogonal to an alignment direction of the liquid crystal of the second reflective liquid crystal panel.