Metasurface Dot Pattern Projector for Thin 3D Sensing Modules
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Solution Overview
Problem
Existing dot pattern projectors for 3D sensing are complex and bulky due to the use of multiple optical components, which complicates integration and exceeds the space constraints in consumer devices, particularly in mobile devices.
Innovation Solution
A single element dot pattern projector using a metasurface chip integrated with a VCSEL array, which combines lens and diffractive functions into a single metasurface layer, allowing direct integration and eliminating the need for separate refractive lenses, and enabling polarization control and arbitrary pattern generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple optical components (refractive lenses and diffractive optical elements) are used to achieve dot pattern multiplication and collimation, then the desired optical performance is achieved, but the device complexity and module thickness increase significantly
Solution Approach 1:
The patent combines multiple optical functions (collimation and dot pattern multiplication) into a single metasurface optical element. This metasurface integrates the functionality of what would traditionally require separate refractive lenses and diffractive optical elements, thereby reducing device complexity while maintaining optical performance
Solution Approach 2:
The metasurface element performs multiple optical functions simultaneously: it acts as both a collimating lens and a diffractive optical element for pattern multiplication. This multi-functionality eliminates the need for multiple specialized components, reducing overall device complexity
2Reliability
If multiple optical components are used for dot pattern projection, then the required optical functions are achieved, but the module thickness exceeds the space available in consumer device bezels
Solution Approach 1:
By merging collimation and pattern multiplication into a single metasurface element positioned close to the VCSEL array, the optical path length is dramatically reduced. This enables the module to fit within the limited bezel space of consumer devices while maintaining all required optical functions
3Device complexity
If a compact design with fewer optical components is used, then the module thickness and device complexity are reduced, but achieving both collimation and dot pattern multiplication becomes more difficult
Solution Approach 1:
The patent replaces traditional mechanical optical components (lenses, DOEs) with a metasurface that can be directly integrated onto the VCSEL array substrate. This substitution enables a monolithic integration approach that reduces the number of discrete components and simplifies the overall manufacturing process
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
This design results in a compact, efficient, and versatile dot pattern projector that can produce a collimated, random, or asymmetric dot pattern with controlled polarization, overcoming space constraints and enhancing integration capabilities.
Implementation Method 1
The metasurface chip includes metasurface elements spaced apart from the laser light source by a distance equal to a back focal length of the metasurface chip, and the laser light source produces light which is diffracted through the metasurface elements to produce a dot pattern
Data Source
AI summary
Disclosed herein are single element dot pattern projectors with a meta-optics. The projectors include a laser light source and a metasurface chip integrated onto the laser light source. The metasurface chip includes metasurface elements spaced apart from the laser light source by a distance equal to the collimating function focal length of the metasurface chip. the laser light source produces light which is diffracted through the metasurface elements to produce a dot pattern. Projectors enabled by meta-optics lead to unique methods of integrating the meta-optic and unique functionality that can be added to the dot pattern.