Holographic Display Controller for Viewing Window and Image Quality
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Solution Overview
Problem
Current 3D image display methods, such as glasses-type and non-glasses-type methods, face challenges in increasing the number of viewpoints and cause eye fatigue due to discrepancies between perceived depth and focus, while holographic displays struggle with image quality issues like Moire noise and chromatic dispersion when using off-axis techniques.
Innovation Solution
A holographic display apparatus and method that employs a spatial light modulator, eye tracking unit, and control unit to generate and adjust hologram data signals and diffraction pattern signals, allowing for off-axis hologram image reproduction, movement of diffraction patterns to reduce Moire noise, and chromatic dispersion correction to enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If off-axis technique is used for hologram image reproduction, then the effective viewing window is increased, but Moire noise and chromatic dispersion occur reducing image quality
Solution Approach 1:
A diffraction pattern is introduced as an intermediary element between the hologram pattern and the viewing window. This diffraction pattern acts as a mediator that redirects light rays to expand the effective viewing window while simultaneously suppressing Moire noise and chromatic dispersion artifacts, thus resolving the contradiction between viewing window size and image quality
Solution Approach 2:
The patent modifies the optical parameters by introducing a diffraction pattern with specific spatial frequency characteristics. By changing the parameters of the diffraction pattern (such as its spatial frequency and orientation), the system achieves both expanded viewing window and maintained image quality, preventing the degradation caused by off-axis techniques
2Manufacturing precision
If diffraction patterns are moved to reduce Moire noise, then image quality is improved, but system complexity increases
Solution Approach 1:
The diffraction pattern is made dynamic rather than static. By dynamically adjusting the position and parameters of the diffraction pattern based on viewing conditions, the system reduces Moire noise and improves image quality without requiring complex hardware modifications. The dynamic adaptation simplifies the overall system compared to static complex optical arrangements
3Manufacturing precision
If chromatic dispersion correction is applied, then image quality is enhanced, but processing time and complexity increase
Solution Approach 1:
Chromatic dispersion correction is performed in advance during the hologram data generation process rather than in real-time during display. By pre-calculating and pre-correcting chromatic dispersion effects in the hologram pattern and diffraction pattern data before display, the system achieves enhanced image quality without adding real-time processing delays or complexity to the display operation
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 effectively increases the effective viewing window, reduces Moire noise, and prevents chromatic dispersion, resulting in improved image quality and reduced eye fatigue for holographic displays by dynamically adjusting the hologram image location and diffraction patterns.
Implementation Method 1
the spatial light modulator forms a hologram pattern and diffracts light according to the input CGH signal, thereby generating a 3D image
Data Source
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AI summary
A holographic display apparatus (100) includes: a light source (110) configured to emit light; a spatial light modulator (120) configured to sequentially display hologram patterns for modulating the light and to sequentially reproduce by diffraction frames of hologram images based on the hologram patterns; and a controller (140) configured to provide hologram data signals to the spatial light modulator, the hologram data signals being used to sequentially generate the hologram patterns. The controller is configured to further provide, to the spatial light modulator, diffraction pattern data signals for forming periodic prism grating diffraction patterns for adjusting transverse locations of the hologram images, wherein the periodic prism grating diffraction patterns move the spatial light modulator along a predetermined direction for each of the frames.