Holographic Display Aperture Enlargement for Wider Viewing Windows
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Solution Overview
Problem
Existing holographic display technologies are limited by the number of viewpoints and cause viewer discomfort due to inconsistencies between perceived depth and eye focus, and they suffer from noise patterns that degrade image quality.
Innovation Solution
Incorporating an aperture enlargement film with a grating layer and light guide layer to enlarge the beam diameter and reduce high-order diffraction noise, combined with an off-axis technique to position the holographic image away from noise spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an off-axis technique is used to reproduce holographic images, then the holographic image can be formed, but high-order diffraction noise appears and the viewing window is limited
Solution Approach 1:
The patent applies apodization filtering to suppress high-order diffraction noise that inherently appears in off-axis holographic techniques. By selectively attenuating certain spatial frequencies in the Fourier domain, the harmful diffraction noise is reduced while preserving the useful holographic image information, thus converting the harmful diffraction effect into a manageable parameter through frequency-domain filtering.
Solution Approach 2:
The patent introduces a Fourier lens as an intermediary optical element between the spatial light modulator and the observation plane. This Fourier lens performs a spatial Fourier transform, allowing apodization filtering to be applied in the frequency domain to suppress high-order diffraction noise before the light reaches the observer, thereby mediating between the hologram generation and the final image quality.
2Device complexity
If a conventional holographic display technique is used, then the system structure is simple, but the viewing window is narrow and image quality is degraded by noise
Solution Approach 1:
The patent extends the viewing window by utilizing the angular dimension through off-axis holographic techniques. By tilting the reference beam and applying apodization filtering in the spatial frequency domain, the system expands the effective viewing angle and window area without significantly increasing the physical footprint of the display device, thus adding a dimensional aspect to the viewing experience.
3Device complexity
If glasses-type methods or lenticular methods are used for 3D display, then the structure is simple, but the number of viewpoints is limited and viewer comfort is reduced
Solution Approach 1:
The patent changes the fundamental parameter of light manipulation from geometric optics (lenticular, parallax barrier) to wave optics (holographic interference and diffraction). By using coherent light and interference patterns, the system achieves continuous parallax and multiple viewpoints without the discrete limitations of conventional methods, fundamentally changing the optical parameter space to enable superior adaptability.
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
Enlarges the viewing window and improves image quality by minimizing high-order diffraction noise, allowing for a more comfortable and immersive holographic experience.
Implementation Method 1
Incorporating an aperture enlargement film with a grating layer and light guide layer to enlarge the beam diameter and reduce high-order diffraction noise
Implementation Method 2
aperture enlargement film with a grating layer and light guide layer
Implementation Method 3
the spatial light modulator forms a hologram pattern and diffracts light according to an input CGH signal, thereby generating a 3D image
Data Source
Figure 1
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Figure 3A
AI summary
Provided is a holographic display apparatus capable of providing an expanded viewing window when reproducing a holographic image via an off-axis technique. The holographic display apparatus includes a spatial light modulator comprising a plurality of pixels arranged two-dimensionally; and an aperture enlargement film configured to enlarge a beam diameter of a light beam coming from each of the plurality of pixels of the spatial light modulator. The beam diameter of each light beam enlarged by the aperture enlargement film may be greater than the width of an aperture of each pixel of the spatial light modulator.