VCSEL Depth Mapping with Variable Pulse Repetition Intervals
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Solution Overview
Problem
Existing depth mapping sensing apparatuses face challenges in achieving real-time three-dimensional imaging with high accuracy and efficiency, particularly in determining the distance and intensity of points in a target scene using time-of-flight techniques.
Innovation Solution
A sensing apparatus incorporating a tunable VCSEL laser with active regions, p-n junctions, and buried tunnel junctions, coupled with a processor and control circuit that select specific pulse repetition intervals and sequences to compute depth coordinates of points in a target scene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional depth mapping sensing apparatuses use time-of-flight techniques to determine distance, then depth measurement capability is achieved, but measurement precision and real-time performance are insufficient
Solution Approach 1:
The patent employs periodic pulsed laser emission with variable pulse repetition intervals to illuminate the target scene. By using periodic pulses instead of continuous illumination, the system achieves both precise time-of-flight measurement and high-speed frame rate operation, resolving the contradiction between measurement precision and real-time performance
Solution Approach 2:
The system dynamically adjusts the pulse repetition interval based on the imaging requirements and target distance. This dynamic parameter adjustment allows the system to optimize between measurement accuracy and frame rate, achieving both high precision depth mapping and real-time imaging capability
2Measurement precision
If VCSEL laser is used with multiple pulse sequences at different PRIs, then depth coordinate computation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the depth measurement process into multiple pulse sequences, each with a different pulse repetition interval. By dividing the measurement into discrete pulse groups with varying PRIs, the system computes depth coordinates more accurately while the modular structure keeps control complexity manageable through systematic organization
Solution Approach 2:
The system uses feedback from the receiver detecting reflected optical signals to compute depth coordinates. The control circuit adjusts subsequent pulse sequences based on previous measurements, creating a feedback loop that improves depth accuracy while the automated feedback mechanism reduces the need for complex manual control
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 solution enables precise and efficient computation of depth coordinates in real-time, enhancing the accuracy and speed of three-dimensional imaging applications.
Implementation Method 1
measurement of the round-trip time, i.e., time-of-flight (ToF), taken by the optical beams as they travel from the source to the target scene and back to a detector array
Implementation Method 2
A sensing apparatus incorporating a tunable VCSEL laser with active regions, p-n junctions, and buried tunnel junctions
Implementation Method 3
one or more active regions including quantum wells and barriers. The active regions are surrounded by one or more p-n junctions
Data Source
AI summary
A monitoring device system has a tunable VCSEL laser having one or more active regions including quantum wells and barriers. The active regions are surrounded by one or more p-n junctions. The one or more active regions can include a selected shape structure, as well as one or more tunnel junctions (TJ). One or more apertures are provided with the selected shape structure. One or more buried tunnel junctions (BTJ) or oxide confine the apertures, additional TJ's, planar structures and or additional BTJ's created during a regrowth process that is independent of a first growth process. A VCSEL output is determined in response to an application of the VCSEL laser. The VCSEL laser includes an HCG grating and a bottom DBR. A receiver receives the optical radiation that is reflected from a target scene and is indicative of respective times of flight of the pulses to and from a target scene. A processor and control circuit select a first pulse repetition interval (PRI), a second PRI, greater than the first PRI, and a third PRI, greater than the second PRI, from a permitted range of PRIs, and to drive the VCSEL laser to emit a first sequence of the pulses at the first PRI as well as a second sequence of the pulses at the second PRI, and a third sequence of the pulses at the third PRI, and to process the signals output by the receiver in response to the first, second, and third sequences of the pulses in order to compute respective depth coordinates of the points in the target scene.