Multibeam Diffraction Grating Backlight for Glasses-Free 3D Displays
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Solution Overview
Problem
Passive electronic displays, which do not emit light, are limited in practical applications due to their inability to emit light, and often require coupling with an external light source to function as active displays, which can be inefficient.
Innovation Solution
The use of a multibeam diffraction grating-based backlighting system that couples light out of a light guide and directs it in various principal angular directions, enabling the creation of a 'glasses-free' multiview electronic display capable of displaying three-dimensional information by modulating light beams as pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If passive displays are coupled with an external light source to enable light emission, then the display can function as an active display, but the system complexity and power consumption increase
Solution Approach 1:
The patent combines the backlight unit and display panel into an integrated structure where the light guide plate is positioned directly behind the display panel. The multibeam diffraction grating is incorporated into the light guide plate itself, merging the light guiding function with the beam shaping function in a single component, thereby reducing overall system complexity while maintaining active display functionality
Solution Approach 2:
The light guide plate serves multiple functions: it guides light from the edge-mounted LED, distributes light uniformly across the display area, and uses the integrated multibeam diffraction grating to shape light into multiple viewing angle beams. This multi-functionality eliminates the need for separate backlight components, reducing system complexity and power consumption
2Illumination intensity
If color filters are used to transform white light into various colors, then the display can show colored images, but the light transmission efficiency decreases
Solution Approach 1:
The multibeam diffraction grating performs preliminary angular separation of light beams before the light reaches the display panel and color filters. By pre-shaping the light into specific viewing angle beams, the system optimizes the path of light through the color filters, reducing unnecessary light absorption and improving overall transmission efficiency
Solution Approach 2:
The diffraction grating creates different beam angles at different locations across the display, with each beam optimized for specific viewing directions. This local optimization of light distribution ensures that color filters receive light at optimal angles, minimizing energy loss while maintaining color accuracy across the entire display area
3Adaptability or versatility
If a multibeam diffraction grating is used to direct light in various angular directions, then glasses-free multiview display is enabled, but the manufacturing precision requirements increase
Solution Approach 1:
The patent uses the light guide plate as an intermediary medium that carries the integrated diffraction grating. This intermediary structure provides mechanical support and optical guidance for the grating, allowing for more tolerant manufacturing specifications compared to free-standing gratings. The light guide plate's larger dimensions and structural rigidity compensate for potential grating fabrication variations
Solution Approach 2:
The system achieves multiple viewing angles by varying the diffraction grating period and orientation at different locations across the light guide plate. By changing these parameters spatially, the patent creates beams directed at different angles without requiring extremely precise uniformity across the entire grating, thereby reducing overall manufacturing precision requirements while maintaining versatile viewing coverage
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 efficient emission of modulated light beams in different directions, enhancing the applicability of passive displays by enabling three-dimensional viewing without the need for external glasses, thereby overcoming the limitations of traditional passive displays.
Implementation Method 1
A multibeam diffraction grating is used to couple light out of a light guide and to direct the coupled out light in a viewing direction of the multiview electronic display. The coupled out light directed in the viewing direction by the multibeam diffraction grating includes a plurality of light beams that have different principal angular directions from one another.
Data Source
AI summary
Multibeam diffraction grating-based backlighting includes a light guide and a multibeam diffraction grating at a surface of the light guide. The light guide is configured to guide light from a light source. The multibeam diffraction grating is configured to couple out a portion of the guided light using diffractive coupling and to direct the diffractively coupled out portion away from the light guide as a plurality of light beams with different principal angular directions having directions corresponding to view directions of a multiview display.