Polar Angle Privacy Display With Switchable Off-Axis Luminance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing privacy displays struggle to provide high luminance in desirable viewing directions while reducing luminance in non-viewing directions effectively, often leading to inadequate off-axis privacy and increased visibility to snoopers.
Innovation Solution
A polar angle control display device incorporating a spatial light modulator, in-plane and out-of-plane polarizers, and a switchable polarisation switch, along with biaxial retarders and surface alignment layers, to dynamically control light polarization and luminance distribution, enabling high luminance in viewing directions and reduced luminance in non-viewing directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional privacy display methods are used, then off-axis privacy is improved, but luminance in viewing directions is reduced
Solution Approach 1:
The patent employs switchable liquid crystal retarders that can dynamically change their optical properties based on applied voltage. These retarders switch between different states to control the polarization state of light, enabling dynamic adjustment of luminance in different viewing directions. The system transitions from a static optical configuration to a dynamic one that can adapt to different viewing conditions.
Solution Approach 2:
The patent changes the optical parameters of the display system by using switchable liquid crystal retarders with varying retardance values. By controlling the voltage applied to these retarders, the system can change the phase shift between orthogonal polarization components, thereby controlling the luminance output in different viewing directions. This parameter control enables high luminance in viewing directions while maintaining privacy.
2Object-affected harmful factors
If switchable liquid crystal retarders are used to control off-axis luminance, then privacy is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple optical functions into a single integrated optical stack. The switchable liquid crystal retarders are integrated with the liquid crystal display layers and polarizers to create a unified system that performs both the display function and the privacy control function. This merging reduces the need for separate optical components and simplifies the overall device structure.
Solution Approach 2:
The switchable liquid crystal retarders serve multiple functions: they act as polarization control elements, luminance modulation devices, and privacy protection mechanisms. By making these components multi-functional, the patent reduces the overall device complexity while achieving the desired privacy protection and luminance control.
3Object-affected harmful factors
If multiple polarizers are used to control polarisation states, then privacy control is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies different types of polarizers (in-plane and out-of-plane) at specific locations within the optical stack to achieve localized polarization control. Each polarizer is positioned and oriented to perform a specific function in the polarization control process, allowing for precise control of light propagation paths while simplifying the manufacturing process by having each component perform a dedicated function.
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 provides enhanced privacy by reducing luminance in non-viewing directions, maintaining high luminance in viewing directions, and offering flexible operation modes, such as landscape, portrait, and share modes, with improved resilience to pressure and reduced coloration, while maintaining symmetric or asymmetric luminance profiles.
Implementation Method 1
an in-plane polariser having an absorption axis in a plane of the in-plane polariser arranged on a side of the spatial light modulator; and an out-of-plane polariser having an absorption axis in a direction having a component out of a plane of the out-of-plane polariser arranged on the same side of the spatial light modulator as the in-plane polariser
Implementation Method 2
The polarisation switch may comprise a switchable layer of liquid crystal material and at least one electrode arranged to switch the state of the liquid crystal material
Data Source
AI summary
A polar angle control display device comprises a spatial light modulator arranged to output light and an out-of-plane polariser having an absorption axis in a direction having a component out of a plane of the out-of-plane polariser. The polar angle control display device can be a switchable privacy display and can achieve high image visibility to an off-axis user in a wide-angle mode of operation and high image security to an off-axis snooper in privacy mode of operation.