Directional Backlight Aperture Adjusting Layer for 3D Display
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Solution Overview
Problem
Current directional backlights for 3D image display apparatuses suffer from poor optical uniformity due to the uneven distribution of light output from the light guide plate, leading to suboptimal 3D image formation.
Innovation Solution
The implementation of a directional backlight system comprising a light source, a light guide plate, a diffractive device with grating units, and an aperture adjusting layer. The diffractive device includes sub-grating units with varying refractive indexes and aperture sizes, optimized for different wavelength bands and directions to enhance light output efficiency and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light guide plate is used to guide light from the light source, then light can be distributed across the display area, but the light output becomes uneven with more light near the propagation start region and less light away from it, resulting in poor optical uniformity
Solution Approach 1:
The diffractive device is divided into multiple grating units corresponding to different regions of the light guide plate. Each grating unit is further segmented into sub-grating units with different aperture ratios, allowing independent optimization of light extraction for each region to compensate for the uneven light distribution from the light guide plate
Solution Approach 2:
Different regions of the diffractive device are assigned different aperture ratios tailored to their specific light output characteristics. Regions receiving more light from the light guide plate use smaller aperture ratios, while regions receiving less light use larger aperture ratios, creating local optimization throughout the display area
2Manufacturing precision
If the aperture ratios of sub-grating units are made different to compensate for uneven light distribution, then optical uniformity improves, but the device structure becomes more complex
Solution Approach 1:
Multiple sub-grating units with different aperture ratios are combined into a single integrated diffractive device structure. This merging approach achieves the benefits of varied aperture ratios while avoiding the complexity of multiple separate components, as all sub-grating units are fabricated together as one piece
Solution Approach 2:
The aperture ratio parameter is varied across different sub-grating units within the diffractive device. By changing this single geometric parameter while maintaining the overall structural framework, the system achieves improved optical uniformity without substantially increasing device complexity
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 configuration significantly improves the optical uniformity of the directional backlight, ensuring consistent light distribution and enhanced 3D image quality by adjusting the aperture ratios and refractive indexes to optimize light output in various directions.
Implementation Method 1
Light propagating in a light guide plate reaches an end of the light guide plate while being totally reflected
Implementation Method 2
a diffractive device comprising a plurality of grating units configured to adjust a direction of light exiting the light guide plate
Data Source
AI summary
A directional backlight and a 3D image display apparatus including the directional backlight are provided. The directional backlight includes a light guide plate guiding light emitted from a light source; a diffractive device configured to adjust the direction of light exiting the light guide plate; and an aperture adjusting layer including a plurality of apertures. The aperture adjusting layer may adjust the optical output efficiency of the diffractive device.