Backlight Unit Beam Expansion for Holographic Display
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Solution Overview
Problem
Current 3D display technologies, such as stereoscopic techniques, cause viewer fatigue due to mismatched depth perception and focus, and require high-resolution spatial light modulators and large data throughput for holographic displays, which can be resource-intensive.
Innovation Solution
A backlight unit for a binocular holographic display device that includes a light source, beam expanders, and a beam deflector, which provides coherent light and adjusts the light beam direction to create separate viewpoints for each eye, reducing data throughput and enhancing resolution by focusing images in predetermined spaces, thus matching depth perception and focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complete holographic display technique is implemented to provide full parallax and match depth perception with focus, then viewer fatigue is reduced and 3D quality is improved, but high-resolution spatial light modulators and large data throughput are required, making the system resource-intensive
Solution Approach 1:
The patent divides the holographic display into separate left-eye and right-eye viewing zones, with each zone receiving light modulated for its specific viewpoint. This segmentation allows the system to process only the necessary viewpoint information for each eye rather than generating complete holographic images for all possible viewpoints, thereby reducing data throughput requirements while maintaining full parallax and depth perception quality
Solution Approach 2:
The patent implements binocular hologram technique that provides holographic images only in the viewing zones corresponding to each eye, rather than generating complete holographic images for all possible viewpoints. This partial action approach reduces data throughput requirements while still achieving the essential function of matching depth perception with focus for the viewer
2Reliability
If high-resolution spatial light modulators are used to implement complete holographic display, then full parallax and depth perception are achieved, but power consumption and resource requirements increase
Solution Approach 1:
The patent segments the holographic display into left-eye and right-eye specific viewing zones, allowing the spatial light modulator to process only the necessary viewpoint information for each eye. This reduces the computational load and power consumption while maintaining full holographic display performance for each viewer's eye
Solution Approach 2:
The system performs partial hologram generation only for the specific viewpoints needed by each eye rather than generating complete holographic images for all possible viewpoints. This partial action reduces power consumption and resource requirements while achieving the essential holographic display function
3Device complexity
If binocular hologram technique is used to reduce data throughput, then resolution condition of spatial light modulator is satisfied, but the system must precisely control light direction to create separate viewpoints
Solution Approach 1:
The patent introduces a beam deflector as an intermediary component between the light source and spatial light modulator. This beam deflector precisely controls the direction of light beams to create separate left-eye and right-eye viewpoints, making the light direction control more manageable and precise while enabling the binocular hologram technique to reduce data throughput
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 viewer fatigue and data requirements by providing a seamless 3D experience with complete parallax, allowing only necessary viewpoint information to be processed, thereby lowering power consumption and improving display efficiency.
Implementation Method 1
a light source unit configured to generate a light beam
Implementation Method 2
a first beam expander configured to expand the light beam in a first direction
Implementation Method 3
a second beam expander configured to expand the light beam in a second direction perpendicular to the first direction
Implementation Method 4
a beam deflector configured to deflect the light beam to control a traveling direction of the light beam
Data Source
Figure 1
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AI summary
Provided is a backlight unit having high optical efficiency and a holographic display device (1000) including the backlight unit. The backlight unit includes a light source unit (100) configured to provide a light beam, a first beam expander (200, 201, ...) configured to mix the light beam provided from the light source unit, expand the light beam in a first direction (A1), and output the mixed and expanded light beam as white light (W), and a second beam expander (300) configured to expand the white light output from the first beam expander in a second direction (A2) perpendicular to the first direction and output the expanded white light as surface light for illuminating a spatial light modulator (600).