Transparent Screen Using Cholesteric Liquid Crystal Dot Arrays
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Solution Overview
Problem
Transparent screens used in image display systems suffer from a 'hot spot' issue where the light source of a projector appears glaringly on the opposite side due to transmitted light, especially with high transparency, and existing solutions to reduce this issue, like uneven surface structures, compromise transparency.
Innovation Solution
A transparent screen comprising a dot array of immobilized cholesteric liquid crystalline phase with selective reflection wavelengths, arranged to reflect specific colors and polarizations, and a λ/4 plate to manage polarized light, reducing hot spots while maintaining high transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the transparency of the screen is increased, then the screen allows better light transmission and clearer images, but hot spots become significantly more glaring
Solution Approach 1:
The screen is segmented into multiple functional layers: a first cholesteric liquid crystal layer for wavelength-selective reflection, a second cholesteric liquid crystal layer for circularly polarized light reflection, and a λ/4 plate layer. This segmentation allows each layer to address specific optical issues independently, enabling high transparency while controlling hot spot glare through coordinated layer interactions.
Solution Approach 2:
The λ/4 plate acts as an intermediary element that converts linearly polarized light to circularly polarized light, enabling the second cholesteric liquid crystal layer to effectively reflect hot spot light. This intermediary transformation is crucial for achieving hot spot suppression while maintaining high screen transparency.
2Object-affected harmful factors
If an uneven structure is imparted to the outermost surface to diffuse light, then hot spots are reduced, but transparency significantly deteriorates
Solution Approach 1:
The invention replaces the mechanical/optical approach of surface texturing with a molecular/optical approach using cholesteric liquid crystal layers. Instead of physically altering the surface to diffuse light, the patent uses wavelength-selective reflection and circularly polarized light reflection through liquid crystal molecular structures, achieving hot spot reduction without compromising transparency.
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 solution effectively minimizes the appearance of hot spots caused by transmitted light while maintaining high transparency and wide viewing angles, allowing for clear image display with reduced glare.
Implementation Method 1
a first layer in which a cholesteric liquid crystalline phase is immobilized; a second layer in which a cholesteric liquid crystalline phase is immobilized... having a first selective reflection wavelength and having a second selective reflection wavelength, respectively
Implementation Method 2
reflects right-handed circularly polarized light... reflects left-handed circularly polarized light
Data Source
AI summary
An object is to provide: a transparent screen having high transparency in which a hot spot caused by transmitted light can be reduced; and an image display system in which visibility of a screen is excellent and a hot spot is reduced by using the transparent screen. The object is achieved by the transparent screen including: a dot array in which dots obtained by immobilizing a cholesteric liquid crystalline phase are two-dimensionally arranged; and a layer that is obtained by immobilizing a cholesteric liquid crystalline phase.