Directional Backlight Unit for Multiview 3D Displays
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Solution Overview
Problem
Current multiview 3D display schemes based on directional backlight exhibit lower optical efficiency and higher crosstalk, which need to be improved for better 3D image display performance.
Innovation Solution
A directional backlight unit is designed with a light source, a light guide plate, a reflective polarizer, and a diffractor, where the reflective polarizer uses a wire grid polarizer with metal wires and a planarization layer, and the diffractor includes grating units that diffract light towards multiple viewing zones, reducing crosstalk and enhancing optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a directional backlight scheme is used for multiview 3D display, then crosstalk is reduced, but optical efficiency deteriorates
Solution Approach 1:
The backlight unit is segmented into distinct functional zones: a light guide plate for light distribution, a reflective polarizer for polarization separation, and a diffractor for directional control. Each segment performs a specific function to optimize overall system performance while maintaining low crosstalk and improved optical efficiency.
Solution Approach 2:
The invention changes the optical parameters by introducing a reflective polarizer that separates light into different polarization states, and a diffractor that controls emission directions. These parameter changes enable simultaneous achievement of low crosstalk through polarization filtering and high optical efficiency through directional light control.
2Reliability
If a directional backlight scheme is used for multiview 3D display, then crosstalk is reduced, but device complexity increases
Solution Approach 1:
The invention merges multiple functions into an integrated backlight unit structure where the light guide plate, reflective polarizer, and diffractor work together as a unified system. This combination achieves crosstalk reduction through coordinated polarization and diffraction effects while maintaining manageable device complexity through functional integration.
Solution Approach 2:
The backlight unit serves multiple functions simultaneously: the light guide plate distributes light uniformly, the reflective polarizer separates polarization states for 3D viewing, and the diffractor controls emission directions for multiple viewing zones. This multi-functionality reduces crosstalk while keeping the device structure relatively simple compared to separate systems.
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 reduces crosstalk and increases optical efficiency, providing a high-quality 3D image display by directing light effectively towards viewing zones, thereby improving the overall performance of 3D image display apparatuses.
Implementation Method 1
a reflective polarizer provided on the emission surface and configured to transmit a portion of the light as first polarized light having a first polarization direction and reflect another portion of the light as second polarized light having a second polarization direction and being perpendicular to the first polarized light
Implementation Method 2
a diffractor configured to diffract the first polarized light transmitted through the reflective polarizer toward a plurality of viewing zones
Implementation Method 3
a light guide plate including: an incident surface on which light emitted by the light source is incident, an emission surface from which the light incident on the incident surface is emitted
Data Source
AI summary
A directional backlight unit includes: a light source configured to emit light; a light guide plate including: an incident surface on which light emitted by the light source is incident, an emission surface from which the light incident on the incident surface is emitted, and a reflective surface facing the emission surface; a reflective polarizer provided on the emission surface and configured to transmit a portion of the light as first polarized light having a first polarization direction and reflect another portion of the light as second polarized light having a second polarization direction and being perpendicular to the first polarized light; and a diffractor configured to diffract the first polarized light transmitted through the reflective polarizer toward a plurality of viewing zones.