Holographic Display VCSEL Array Speckle Noise Reduction
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Solution Overview
Problem
Current holographic display methods suffer from image noise due to the diffraction of reference light by pixel lattices in spatial light modulators, leading to reduced image quality and viewer discomfort.
Innovation Solution
A holographic display apparatus utilizing a light source with multiple vertically-cavity surface-emitting lasers (VCSELs) spaced apart to reduce time-coherence and speckle noise, combined with a focusing optical system that adjusts the focal position to avoid lattice spots, and an eye-tracking sensor to select the appropriate light source for optimal viewing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a small-sized light source is used in head-mounted display, then device size is reduced, but speckle noise increases
Solution Approach 1:
The patent divides a single light source into multiple VCSELs (vertical-cavity surface-emitting lasers) arranged in an array. Each VCSEL emits coherent light, but the combination of multiple spatially separated VCSELs with different coherence lengths reduces the overall speckle noise while maintaining the compact form factor required for head-mounted displays.
2Manufacturing precision
If high-resolution spatial light modulator is used, then holographic image quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the coherence parameters of the light source by using multiple VCSELs with different coherence lengths instead of a single high-coherence laser. This parameter change allows the system to achieve good holographic image quality without requiring extremely high-resolution spatial light modulators, thereby reducing manufacturing complexity and cost.
3Adaptability or versatility
If multiple viewpoints are increased, then holographic display coverage is improved, but viewer fatigue increases due to mismatch between depth perception and focus
Solution Approach 1:
The patent incorporates an eye-tracking sensor that dynamically adjusts the holographic display parameters based on the viewer's eye position and focus. This dynamic adaptation ensures that the displayed hologram maintains proper depth-perception-focus correspondence for the specific viewer, reducing fatigue while providing wide viewing coverage through multiple viewpoints.
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 reduces image noise and enhances the quality of holographic images by minimizing the impact of lattice spots and speckle noise, providing a more comfortable viewing experience with improved luminance and reduced chromatic dispersion.
Implementation Method 1
a light source configured to emit light, the light source including a plurality of vertical-cavity surface-emitting lasers (VCSELs) that are spaced apart from one another
Implementation Method 2
A holographic display apparatus utilizing a light source with multiple vertically-cavity surface-emitting lasers (VCSELs) spaced apart to reduce time-coherence and speckle noise
Implementation Method 3
a spatial light modulator configured to, based on a hologram data signal, modulate the light emitted by the light source
Implementation Method 4
a focusing optical system configured to focus an image formed by the spatial light modulator using a Maxwellian view method
Implementation Method 5
focus an image formed by the spatial light modulator using a Maxwellian view method
Implementation Method 6
Each VCSEL of the plurality of VCSELs may be configured to emit light having a wavelength that is different from a wavelength of light emitted by at least two neighboring VCSELs
Implementation Method 7
providing a more comfortable viewing experience with improved luminance and reduced chromatic dispersion
Data Source
AI summary
Provided is a holographic display apparatus. A holographic image display apparatus includes: a light source configured to emit light, the light source including a plurality of vertical-cavity surface-emitting lasers (VCSELs) that are spaced apart from one another; a spatial light modulator configured to, based on a hologram data signal, modulate the light emitted by the light source; and a focusing optical system configured to focus an image formed by the spatial light modulator using a Maxwellian view method.