Optical Screen Structure for Ambient Light Blocking and High Contrast
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Solution Overview
Problem
Conventional electrically controlled scattering elements in projection screens suffer from poor image contrast due to the inability to block ambient light effectively, especially in bright environments.
Innovation Solution
An electrically controlled optical screen equipped with a switchable scattering element and an electrically controlled decorating module, utilizing a combination of polarizers, quarter-wave plates, cholesteric liquid crystal layers, and electrically controlled wave plates to switch between scattering and transparent states, allowing for improved light absorption and reflection to enhance image contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an electrically controlled scattering element is used to switch between scattering and transparent states, then the optical mode switching capability is improved, but the image contrast deteriorates due to inability to block ambient light
Solution Approach 1:
The patent employs a composite structure combining scattering element, polarizing elements, and cholesteric liquid crystal layer to achieve both optical mode switching and ambient light blocking functions, resolving the contradiction between versatility and harmful factor resistance
Solution Approach 2:
The cholesteric liquid crystal layer acts as an intermediary element that selectively blocks ambient light while allowing projected image light to pass through, thereby improving image contrast without compromising the optical mode switching capability
2Illumination intensity
If the non-projection side is exposed to bright environment, then the scattering element cannot block light, but the image contrast deteriorates
Solution Approach 1:
The patent utilizes the unique optical properties of cholesteric liquid crystal that can selectively reflect and block light based on its molecular structure parameters, enabling effective ambient light blocking from the non-projection side while maintaining high image contrast
3Object-affected harmful factors
If a cholesteric liquid crystal layer is added to block ambient light, then the image contrast is improved, but the device complexity increases
Solution Approach 1:
The cholesteric liquid crystal layer serves multiple functions simultaneously: it blocks ambient light to improve contrast, maintains optical mode switching capability, and can provide decorative patterns, thereby justifying the added structural complexity through multi-functionality
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 reduces the impact of ambient light on image quality, enhancing contrast and providing various optical modes for different visual experiences, including projection, decoration, and lighting.
Implementation Method 1
The switchable scattering element is configured to switch between a scattering state and a transparent state
Implementation Method 2
The cholesteric liquid crystal layer is configured to reflect one of left-handed circularly polarized light or right-handed circularly polarized light
Implementation Method 3
The electrically controlled decorating module includes a first polarizer, a first quarter-wave plate, a cholesteric liquid crystal layer, an electrically controlled wave plate, a second quarter-wave plate and a second polarizer stacked in sequence
Data Source
AI summary
An electrically controlled optical screen including a switchable scattering element and an electrically controlled decorating module is provided. The switchable scattering element is disposed on a side of the electrically controlled decorating module and is configured to switch between a scattering state and a transparent state. The electrically controlled decorating module includes a first polarizer, a first quarter-wave plate, a cholesteric liquid crystal layer, an electrically controlled wave plate, a second quarter-wave plate and a second polarizer, which are sequentially stacked. The electrically controlled wave plate has a liquid crystal layer. The second polarizer is disposed between the switchable scattering element and the second quarter-wave plate.