Wavelength-Tunable Optical Pattern Projector for 3D Imaging
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Solution Overview
Problem
Existing visual display systems, particularly head-mounted displays (HMDs) and near-eye displays (NEDs), lack efficient and compact light sources for eye tracking and 3D imaging, which are essential for enhancing user experience in virtual reality (VR), augmented reality (AR), and mixed reality (MR) applications.
Innovation Solution
A wavelength-tunable optical pattern projector is developed, comprising a liquid crystal tunable filter (LCTF) and a spatial filter, which projects a patterned light beam with alternating bright and dark regions, allowing for 3D imaging and eye tracking by capturing images at different wavelengths and patterns, using a compact and low-weight multi-layer LC structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional light sources are used in HMDs and NEDs, then the system can provide basic illumination, but the system lacks efficiency and compactness for 3D imaging and eye tracking applications
Solution Approach 1:
The patent combines a spatial light modulator and a tunable filter into a single integrated device structure. The spatial light modulator is positioned in front of the tunable filter, allowing both spatial pattern generation and wavelength tuning to occur within one compact unit. This merging eliminates the need for separate components and reduces overall system complexity while maintaining high efficiency for 3D imaging and eye tracking.
Solution Approach 2:
The integrated device serves multiple functions: it generates spatially patterned light, tunes wavelength, and provides illumination for both eye tracking and 3D imaging simultaneously. This multi-functionality replaces what would traditionally require multiple separate light sources and filtering systems, thereby improving productivity without proportionally increasing device complexity.
2Adaptability or versatility
If multiple components are used for wavelength tuning and spatial patterning, then functional requirements are met, but the system size and weight increase
Solution Approach 1:
By merging the spatial light modulator and tunable filter into one integrated component, the patent reduces the total number of parts required for wavelength tuning and spatial patterning. This consolidation directly reduces the weight of the display system while preserving full adaptability for different wavelengths and patterns needed in VR/AR/MR applications.
3Adaptability or versatility
If multiple components are used for wavelength tuning and spatial patterning, then functional requirements are met, but the system size increases
Solution Approach 1:
The integrated device structure combines spatial light modulation and wavelength filtering in a single compact unit. This merging eliminates the spatial separation required for multiple components, thereby reducing the overall volume of the display system while maintaining full adaptability for spatial pattern generation across different wavelengths.
4Measurement precision
If conventional illuminators are used, then basic illumination is provided, but accurate 3D imaging and eye tracking cannot be achieved
Solution Approach 1:
The patent integrates spatial light modulation and wavelength tuning capabilities into a single illuminator unit. This integration enables the generation of spatially patterned, wavelength-tunable light that is essential for accurate 3D imaging and eye tracking, while avoiding the complexity of multiple separate components through their unified design.
Solution Approach 2:
The illuminator employs dynamically可调 spatial patterns and wavelength tuning capabilities that can be adjusted in real-time. The spatial light modulator can generate different patterns (e.g., stripes, grids) and the tunable filter can switch wavelengths dynamically, enabling precise measurement for 3D imaging and eye tracking without requiring complex static multi-component systems.
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
Enables accurate 3D imaging and eye tracking by discerning object composition and depth through distortion analysis of patterned light reflections, providing enhanced user experience in VR, AR, and MR environments.
Implementation Method 1
a liquid crystal tunable filter (LCTF) for spectrally filtering the light and for tuning a center wavelength of the light within the wavelength band
Implementation Method 2
filtering the light to provide a wavelength-tunable light beam
Implementation Method 3
a spatial filter for spatially modulating the wavelength-tunable light beam to provide a patterned light beam comprising a pattern of alternating bright and dark regions
Implementation Method 4
receiving a portion of the patterned light beam reflected from the object
Data Source
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Figure 3A~4
Figure 5A~5B
AI summary
A wavelength-tunable patterned-beam projector for object imaging includes a broadband light source for emitting light spanning a wavelength band and a liquid crystal tunable filter for spectrally filtering the light and for tuning a center wavelength of the light. A liquid crystal based spatial filter spatially modulates the light to provide the patterned light beam having alternating bright and dark regions in a cross-section of the beam. The projector may be used in a near-eye display to illuminate an eye of the user for eye tracking, and to illuminate surroundings for 3D imaging and/or ranging.