Switchable Cholesteric LC Parallax Barrier for 3D Displays
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Solution Overview
Problem
Conventional 3D display devices using non-polarized light sources, such as OLED, PDP, and CRT, suffer from severe light loss when employing liquid crystal barriers for 3D display, resulting in low brightness due to the need for two polarizers.
Innovation Solution
A switchable cholesteric LC parallax barrier is implemented, comprising a non-polarized light display unit, a cholesteric liquid crystal cell, a quarter-wave plate, and a polarizer, where the polarizer's absorption axis forms a specific angle with the quarter-wave plate's fast axis, allowing for reduced light absorption and improved brightness by using only one polarizer during 3D display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If two polarizers are used in conventional 3D display devices with non-polarized light sources, then 3D display can be achieved, but severe light loss occurs resulting in low brightness
Solution Approach 1:
The invention extracts and removes one polarizer from the conventional two-polarizer configuration. By using a cholesteric liquid crystal layer that inherently provides circular polarization without requiring a polarizing plate, the system eliminates the need for one polarizer, thereby reducing light loss and improving brightness while maintaining 3D display functionality
Solution Approach 2:
The invention changes the polarization mechanism from linear polarization (requiring two polarizers) to circular polarization (achieved through cholesteric liquid crystal layer). This parameter change in the polarization type allows the system to maintain 3D display capability while reducing the number of polarizing components needed, thus minimizing light loss
2Reliability
If a liquid crystal barrier is adopted for 3D display in non-polarized light display devices, then 3D imaging is achieved, but two polarizers are required leading to severe light loss
Solution Approach 1:
The cholesteric liquid crystal layer serves multiple functions simultaneously: it acts as both the 3D barrier layer and the circular polarization generator. This multi-functionality eliminates the need for separate polarizing plates, reducing light loss while maintaining reliable 3D display functionality
Solution Approach 2:
The cholesteric liquid crystal layer is self-sufficient in generating circular polarization without requiring external polarizing plates. This self-service capability allows the system to achieve 3D display with reduced light loss by eliminating redundant polarizing components
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 enhances the brightness of 3D displays by minimizing light loss, as the cholesteric liquid crystal layer selectively blocks or transmits light, achieving effective 3D imaging with reduced polarizer usage.
Implementation Method 1
a liquid crystal cell 2 provided on the non-polarized light display unit 1, the liquid crystal cell 2 including cholesteric liquid crystal layer
Implementation Method 2
a quarter-wave plate, wherein the absorption axis of the polarizer forms a specific angle with the quarter-wave plate's fast axis
Implementation Method 3
a polarizer, wherein the absorption axis of the polarizer forms a specific angle with the quarter-wave plate's fast axis
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
A display device for producing 3D images employs a cholesteric liquid crystal cell (2) in a switchable parallax barrier (2,3,4) in front of a display unit (1). The display unit typically emits unpolarised light (e.g. OLED or PDP), but it may also be an LCD. The barrier further comprises a quarter wave plate (3) interposed between a linear polariser (4) and the cholesteric cell (2) at the front of the device. The barrier has three states: in the OFF state no light is transmitted and the liquid crystal is in its planar texture; in the fully-ON state, a 2D image is obtained while in the partially-ON state only some regions of the barrier are completely transmissive and a 3D image is obtainable. In further embodiments a reflector (5) alone or in combination with a further quarter-wave plate (6) improves the recycling of light.