Switchable Grating Display for Dual-Angle Privacy Viewing
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Solution Overview
Problem
Conventional switchable displays fail to simultaneously allow image content to be visible to on-axis and off-axis viewers at smaller viewing angles, both positive and negative relative to the normal, and do not enable switching between these modes effectively.
Innovation Solution
A display system comprising a backlight that emits collimated polarized light, a display panel, and a grating system with a retarder, where the grating system and retarder can switch between different polarization states to optimize image intensity profiles at various viewing angles, allowing the image to be visible to viewers at specific angles by adjusting the applied signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional privacy film is applied to limit viewing angles, then privacy protection is improved, but the image content becomes invisible to off-axis viewers at smaller viewing angles
Solution Approach 1:
The patent employs a switchable grating system with multiple states that dynamically changes the intensity profile of emitted light. By applying different voltages to the grating structure, the system can switch between a first state that directs light at a first angle and a second state that directs light at a second angle, enabling dynamic control over viewing angles and image visibility
Solution Approach 2:
The grating system modifies the physical parameters of light transmission by changing the effective refractive index and pitch parameters through applied voltage. This allows the system to alter the intensity profile versus transmission angle, switching between different viewing configurations to balance privacy protection with image visibility
2Loss of information
If a privacy film is used to protect information from oblique angles, then information security is improved, but the image content becomes invisible or low intensity at maximum viewing angles
Solution Approach 1:
The switchable grating system dynamically adjusts the intensity profile to maintain image intensity at desired viewing angles. When switched to the appropriate state, the grating ensures that the maximum of the intensity profile occurs at the intended viewing angle, preventing information loss while maintaining image visibility
Solution Approach 2:
The system incorporates sensors that detect viewer position and provide feedback to control the grating state. This feedback mechanism ensures that the grating switches to the state that maintains optimal image intensity for the detected viewer position, preventing information loss while keeping the image visible
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
Enables switching between multiple viewing angles by providing distinct intensity profiles at different transmission angles, ensuring the image is clearly visible to viewers at both positive and negative angles, and optimizing luminance for specific viewer positions.
Implementation Method 1
The grating system includes a plurality of substantially parallel elongated features extending along an in-plane first direction and arranged along an orthogonal in-plane second direction. The grating system is configured to receive and transmit an incident polarized light as a first transmitted light having different first and second polarization states
Implementation Method 2
The at least one retarder is configured to have at least different first and second retardation states. In response to the respective first and second retardation states of the at least one retarder, the emitted polarized image light exiting the display system includes different first and second intensity profiles versus transmission angle
Implementation Method 3
a backlight configured to emit substantially collimated polarized light from an emission surface thereof. The emitted polarized light is polarized along a polarization direction
Data Source
AI summary
The present disclosure provides a display system. The display system includes a backlight configured to emit substantially collimated polarized light from an emission surface thereof. The emitted polarized light is polarized along a polarization direction. The display system further includes a display panel configured to receive an illumination light and form an image. The display system further includes a grating system substantially coextensive in length and width with the display panel and the emission surface. The grating system includes a plurality of substantially parallel elongated features extending along an in-plane first direction and arranged along an orthogonal in-plane second direction. The grating system is configured to receive and transmit an incident polarized light as a first transmitted light having different first and second polarization states in response to different respective first and second signals applied to the grating system.