Chip-Scale LiDAR Dynamic Spatial Filter for Ambient Light Rejection
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Solution Overview
Problem
Solid-state LiDAR devices face challenges in increasing detection range due to ambient light interference and lack of effective filtering mechanisms, as they lack mechanical rotating scanners and detectors, leading to reduced signal-noise ratios and missed signals from large reflection surfaces.
Innovation Solution
A chip-scale LiDAR device with a dynamic spatial filter, utilizing a 2-D pixel array of Geiger-mode single-photon avalanche diodes (SPADs) and a dynamically configured spatial filter that blocks ambient light and noises based on steering directions, enhancing signal-noise ratios without increasing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If solid-state LiDAR devices use high-grade optics and rotating assembly to create wide field of view, then measurement precision and detection range are improved, but device complexity and size increase
Solution Approach 1:
The patent replaces mechanical rotating scanners with a fixed optical system using 2-D pixel arrays and dynamic spatial filtering. The mechanical rotation is substituted by electronic pixel addressing and dynamic aperture control, eliminating moving parts while maintaining wide field of view capability
Solution Approach 2:
The patent transitions from 1-D linear pixel arrays to 2-D pixel arrays, adding a spatial dimension to signal detection. This enables simultaneous detection across a wider field of view without mechanical scanning, as the 2-D array can capture reflected light from multiple angles concurrently
2Device complexity
If solid-state LiDAR devices lack mechanical rotating scanners, then device complexity is reduced, but signal-noise ratio deteriorates due to ambient light interference
Solution Approach 1:
The patent implements a dynamic spatial filter with adjustable apertures that can change position and size in real-time based on detected signal directions. This dynamic adaptation allows the filter to track and block ambient light from varying sources while maintaining openness to reflected laser signals, solving the static filtering limitation
Solution Approach 2:
The patent introduces a spatial filter as an intermediary element between the 2-D pixel array and ambient light sources. This filter acts as a selective mediator that blocks harmful ambient light while allowing desired reflected laser signals to reach the detectors, reducing noise without sacrificing detection capability
3Ease of manufacture
If solid-state LiDAR devices use fixed spatial filter, then manufacturing cost is reduced, but detection range is limited due to inability to track signals from large reflection surfaces
Solution Approach 1:
The patent transforms a static spatial filter into a dynamic one with movable apertures that can track and follow reflected laser signals across different angular positions. This dynamic capability enables the filter to maintain optimal positioning relative to moving targets, extending detection range without requiring multiple fixed filters
Solution Approach 2:
The patent designs a multi-functional spatial filter system that combines signal tracking, noise blocking, and aperture adjustment capabilities in a single device. This universal filter can adapt to various target positions and ambient light conditions, replacing the need for multiple specialized fixed filters
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 combination of a 2-D SPAD array and dynamic spatial filter effectively increases the detection range and signal-noise ratio of solid-state LiDAR devices, compensating for the absence of mechanical scanners and detectors, while maintaining cost-effectiveness.
Implementation Method 1
A chip-scale LiDAR device can include a chip with three layers. The first layer includes a number of micromechanical system (MEMS) mirrors. The second layer includes a laser source, a beam splitter connected to the laser source, a number of waveguides, each connected to the beam splitter, and a number of beam deflectors, each beam deflector coupled with one of the number of waveguides. The third layer includes a receiving unit for receiving and processing reflected laser signals
Implementation Method 2
The second layer includes a laser source, a beam splitter connected to the laser source
Implementation Method 3
The second layer includes a laser source, a beam splitter connected to the laser source, a number of waveguides, each connected to the beam splitter
Implementation Method 4
a number of waveguides, each connected to the beam splitter, and a number of beam deflectors, each beam deflector coupled with one of the number of waveguides
Data Source
AI summary
In one embodiment, a chip-scale LiDAR device can include a chip with three layers. The first layer includes a number of micromechanical system (MEMS) mirrors. The second layer includes a laser source; a beam splitter connected to the laser source; a number of waveguides, each connected to the beam splitter; and a number of beam deflectors, each beam deflector coupled with one of the number of waveguides. The third layer includes a receiving unit for receiving and processing reflected laser signals of one or more laser beams from the laser source. The first layer, the second layer, and the third layer are vertically attached to each other using either wafer bonding and/or solder bonding.