Coherent LIDAR Grating Array for Mirrorless 3D Depth Sensing
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Solution Overview
Problem
Conventional LIDAR systems face challenges with moveable mirrors that are large, expensive, and prone to failure, and 2D solid state scanners are complex and difficult to scale due to numerous controllable elements, while direct detection limits resolution and is sensitive to interference and partial reflections.
Innovation Solution
A LIDAR system using coherent light and an array of coherent receivers with varying grating pitch, coupled with a frequency-swept laser and digital signal processing, enables high-resolution 3D imaging without moving parts, by measuring depth through wavelength tuning and using phased arrays for reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If moveable mirrors are used in conventional LIDAR systems, then beam steering is achieved, but the system becomes large, expensive, and prone to failure
Solution Approach 1:
The patent replaces mechanical moveable mirrors with an acoustic radiation pressure field that exerts force on acoustic radiation pressure nodes to achieve beam steering. This substitution eliminates mechanical moving parts while maintaining the beam steering function, thereby improving reliability and reducing system complexity
Solution Approach 2:
The patent changes the parameters of the acoustic radiation pressure field (frequency, amplitude, phase) to control the position of acoustic radiation pressure nodes, which in turn controls the beam steering direction. This parameter-based control replaces mechanical position control, enabling reliable electronic steering without moving parts
2Ease of operation
If 2D solid state scanners with numerous controllable elements are used, then beam steering is achieved, but the device complexity increases and scalability becomes difficult
Solution Approach 1:
The patent extracts the essential function of beam steering from complex 2D solid state scanner architectures by using acoustic radiation pressure nodes in a fluid medium. This extraction simplifies the system to essential components (acoustic transducers and fluid medium) while removing unnecessary controllable elements, reducing device complexity
Solution Approach 2:
The acoustic radiation pressure field serves multiple functions simultaneously: beam steering, beam focusing, and beam shaping. This multi-functionality replaces the need for separate controllable elements for each function, reducing overall device complexity and improving scalability
3Device complexity
If direct detection is used in LIDAR systems, then detection is simplified, but resolution is limited and the system becomes sensitive to interference and partial reflections
Solution Approach 1:
The patent introduces coherent detection as an intermediary between the received optical signal and the measurement process. By using coherent detection with local oscillator mixing, the system achieves high resolution depth measurement while maintaining manageable system complexity through standardized photodetector implementations
Solution Approach 2:
The patent combines multiple detection techniques (coherent detection, phase modulation, frequency sweeping) into a composite detection system. This composite approach overcomes the limitations of direct detection by integrating multiple functional elements that work together to achieve high resolution while managing 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 system achieves high sensitivity, high depth resolution, and scalability with reduced complexity and power consumption, capable of detecting objects transparent to direct detection systems and resistant to interference.
Implementation Method 1
A LIDAR system uses an array of gratings with variable pitch
Implementation Method 2
A LIDAR system uses an array of gratings with variable pitch and coherent receivers
Implementation Method 3
measuring depth through wavelength tuning
Data Source
AI summary
A method, apparatus, and system for imaging a scene.