Metasurface Pattern Projector for Compact Depth Sensing
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Solution Overview
Problem
Conventional structured light and ToF sensors utilize diffractive optical elements (DOEs) that result in a thick structure due to their combination with lenses, limiting their practical applications.
Innovation Solution
A pattern projector incorporating a laser source and a metasurface that diffracts laser beams to form patterns on a projected surface, utilizing a thinner metasurface instead of a DOE combined with a lens, allowing for a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diffractive optical element (DOE) combined with a lens is used to form light patterns, then the structured light sensor or ToF sensor can obtain depth data, but the sensor structure becomes thick
Solution Approach 1:
The patent changes the optical parameter by replacing the conventional lens-DOE combination with a metasurface that has different diffraction characteristics. The metasurface uses sub-wavelength structures to achieve phase modulation, fundamentally changing how light is diffracted and focused, thereby reducing the optical path length and overall sensor thickness while maintaining depth measurement capability
Solution Approach 2:
The patent employs a metasurface, which is a thin film structure with sub-wavelength patterns, to replace the bulky lens-DOE assembly. This thin film approach allows the optical functionality to be achieved in a much thinner profile, directly addressing the thickness contradiction while preserving the pattern projection function necessary for depth sensing
2Ease of manufacture
If a diffractive optical element (DOE) with multiple diffraction orders is used, then light patterns can be formed, but the surface complexity and structure thickness increase
Solution Approach 1:
The patent applies local quality by designing the metasurface with spatially varying sub-wavelength structures that are optimized for specific local functions. Each region of the metasurface has tailored properties to control the diffraction of light locally, achieving the desired pattern formation without requiring the complex multi-order structure of conventional DOEs, thereby simplifying the overall device complexity
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 thinner structure of the pattern projector enables more versatile and efficient depth sensing capabilities while reducing the overall size and thickness compared to traditional DOE-lens configurations.
Implementation Method 1
The metasurface is disposed on a path of the laser beam and configured to diffract the laser beam onto a projected surface, so as to form a pattern on the projected surface
Data Source
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AI summary
A pattern projector including a laser source, a metasurface, and a light sensor is provided. The laser source is configured to emit a laser beam. The metasurface is disposed on a path of the laser beam and configured to diffract the laser beam onto a projected surface, so as to form a pattern on the projected surface. The light sensor is disposed beside the metasurface and configured to sense the pattern.