Holographic Display Viewing Window Expansion With Irregular Optics
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Solution Overview
Problem
Existing 3D image display methods, such as glasses-type and non-glasses-type methods, are limited by the number of viewpoints due to binocular parallax and cause viewer discomfort due to discrepancies between perceived depth and eye focus, while holographic displays face challenges in expanding the viewing window and reducing noise artifacts.
Innovation Solution
A holographic display apparatus incorporating a spatial light modulator and an optical element with irregularly arranged light transmission patterns, such as openings or micro lenses, to increase the effective resolution and expand the viewing window, while using an off-axis technique to minimize noise and viewer discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a scatter plate with pseudo-random binary phase distribution is used to enlarge image size and range of angles, then the viewing window is expanded, but noise artifacts increase and image quality deteriorates
Solution Approach 1:
The patent changes the phase distribution parameters from pseudo-random binary (0 and π) to continuous phase values ranging from 0 to 2π. This parameter change allows for more precise control of light diffraction, expanding the viewing window while reducing noise artifacts through optimized phase modulation.
Solution Approach 2:
The patent uses a phase-only modulator to create a phase copy of the desired light field distribution. By modulating only the phase component of the light wave while maintaining amplitude uniformity, the system reproduces the target intensity distribution at the viewing plane without introducing the noise associated with amplitude modulation methods.
2Adaptability or versatility
If conventional holographic display techniques are used, then 3D images can be generated, but the viewing window is limited and noise artifacts are present
Solution Approach 1:
The patent transitions from conventional amplitude-based holographic modulation to phase-based modulation, adding a dimensional transformation in the optical parameter space. This phase dimension enables broader angular coverage and expanded viewing window while maintaining 3D image generation capabilities.
Solution Approach 2:
The system changes the modulation parameter from amplitude to phase, using phase-only modulators to control light distribution. This parameter transformation expands the viewing window beyond conventional limits while reducing the noise artifacts inherent in amplitude-based approaches.
3Area of stationary object
If amplitude masks with pinholes are used per SLM pixel, then viewing window can be expanded, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent replaces mechanical amplitude masks with pinholes with a phase-only modulator system. This substitution eliminates the need for precise mechanical fabrication of masks while achieving viewing window expansion through programmable phase modulation, significantly simplifying device manufacturing.
Solution Approach 2:
The phase-only modulator serves multiple functions: it expands the viewing window, reduces noise artifacts, and enables programmable control of light distribution. This single component replaces the need for complex amplitude masks and their precise fabrication, providing a universal solution for multiple performance improvements.
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 apparatus achieves an expanded viewing window with reduced noise artifacts, allowing for comfortable 3D image observation without the need for high-precision eye trackers and actuators, thereby enhancing the holographic display experience.
Implementation Method 1
the spatial light modulator forms a hologram pattern and diffracts light according to an input CGH signal, thereby generating a 3D image
Implementation Method 2
an optical element with irregularly arranged light transmission patterns, such as openings or micro lenses, to increase the effective resolution and expand the viewing window
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Provided is a holographic display apparatus (100,200) including a light source (110) configured to emit light, a spatial light modulator (130) configured to form a hologram pattern to modulate the light incident thereon and reproduce a hologram image, the spatial light modulator including a plurality of display pixels (130a,130b) that are arranged two-dimensionally, and an optical element (140) provided upstream or downstream of the spatial light modulator, the optical element including an array of a plurality of light transmission patterns (142,143) that are arranged irregularly.