Slanted Diffraction Gratings for Unilateral Multiview Displays
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Solution Overview
Problem
Passive electronic displays, such as LCDs and EP displays, are limited in their practical applications due to their inability to emit light, requiring external light sources for functionality, which can be inefficient and restrictive.
Innovation Solution
The implementation of a unilateral backlight system utilizing slanted diffraction gratings to direct light in a unilateral direction, enabling the creation of multiview displays that provide different perspectives by scattering light as directional beams, effectively transforming passive displays into active ones with enhanced functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If passive displays are coupled to external light sources to enable light emission, then the displays can function as active displays, but the device complexity and power consumption increase
Solution Approach 1:
The patent combines the backlight unit and diffraction grating into a single integrated optical system. The diffraction grating is positioned within the backlight unit structure, merging two previously separate components (light source and light directing element) into one unified assembly, thereby reducing overall system complexity while maintaining active display functionality
Solution Approach 2:
The backlight unit is designed to serve multiple functions simultaneously: it provides illumination for the display panel and acts as a light field generator for 3D/multiview capabilities through the integrated diffraction grating. This multi-functionality eliminates the need for separate 3D optical elements, reducing device complexity
2Illumination intensity
If traditional backlights are used to illuminate passive displays, then light emission is achieved, but the light is emitted in multiple directions reducing viewing control
Solution Approach 1:
The diffraction grating introduces directional control at specific locations within the backlight unit. By positioning the grating at particular sites and orienting it at specific angles, the system creates localized directional light beams that maintain overall illumination while providing controlled viewing directions for different viewer positions
Solution Approach 2:
The patent changes the angular distribution parameter of emitted light by introducing a diffraction grating with specific pitch and orientation. This transforms the isotropic light emission of traditional backlights into anisotropic emission with controlled angular characteristics, enabling directional light fields for multiview displays
3Adaptability or versatility
If diffraction gratings are used to create directional light beams for multiview displays, then multiple viewing perspectives are enabled, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs replication techniques to mass-produce diffraction grating structures at low cost. By using molding or coating processes that can replicate the grating pattern across large areas, the system achieves multiview functionality without requiring high-precision manual fabrication, thereby reducing manufacturing precision requirements while maintaining optical performance
Solution Approach 2:
The diffraction grating is designed with asymmetric orientation angles (e.g., 45 degrees) rather than symmetric configurations. This asymmetric design simplifies the optical path geometry and reduces the number of precise alignment requirements during assembly, thereby lowering manufacturing precision demands while still achieving the desired multiview effect
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 solution allows for the creation of multiview displays that offer multiple perspectives without the need for external light sources, enhancing the usability and functionality of passive displays in various applications, including mobile devices and automotive consoles.
Implementation Method 1
unilateral diffractive elements comprising slanted diffraction gratings. The unilateral diffractive elements are configured to scatter light out of the unilateral backlight as directional light beams having a unilateral direction
Data Source
AI summary
A unilateral backlight and a unilateral multiview display employ an array of unilateral diffractive elements configured to provide directional light beams having a unilateral direction. A unilateral diffractive element of the unilateral diffractive element array comprises a slanted diffraction grating configured to provide a directional light beam by diffractive scattering of light guided in a light guide. The unilateral multiview display further includes light valves configured to modulate a plurality of directional light beams as multiview image having the unilateral direction.