Solid-State Ranging Circuit for Precise Time-of-Flight Sensing
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Solution Overview
Problem
Conventional mechanical LiDAR sensors are large, expensive, and have poor durability due to their reliance on physical rotation for scanning, which limits their effectiveness in various applications.
Innovation Solution
A ranging device utilizing a sensor array with a row driver and time detection circuit that detects reflected light by generating trigger signals and using multiple clock signals to measure time intervals, allowing for accurate distance measurement through a combination of first and second operations in the time-to-digital converter circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical LiDAR sensor uses physical rotation to scan surroundings, then it can achieve wide coverage scanning, but it becomes large, expensive, and has poor durability
Solution Approach 1:
The patent replaces the mechanical rotation system with an electronic scanning approach using a sensor array that detects reflected light from multiple directions simultaneously. The row driver controls the sensor array row by row to output trigger signals, eliminating moving mechanical parts while maintaining scanning capability through electronic control and signal processing.
Solution Approach 2:
The patent transitions from one-dimensional mechanical rotation to a two-dimensional sensor array configuration. The sensor array includes multiple rows and columns that can detect light from different spatial positions simultaneously, adding a spatial dimension to the detection capability and eliminating the need for mechanical rotation to achieve coverage.
2Adaptability or versatility
If a mechanical LiDAR sensor uses physical rotation, then it can scan surroundings, but it increases device size and cost
Solution Approach 1:
The patent divides the detection task across multiple segments - the sensor array is organized into multiple rows and columns, with each row containing multiple sensors. The row driver controls each row independently to output trigger signals, allowing parallel detection from multiple spatial positions without requiring a single rotating component.
Solution Approach 2:
The sensor array provides multi-functional capability by detecting reflected light from multiple directions simultaneously through its multiple rows and columns. This single static structure performs the scanning function that would otherwise require mechanical rotation, achieving versatile spatial detection without increasing device volume.
3Measurement precision
If conventional LiDAR uses mechanical rotation for scanning, then it achieves coverage detection, but measurement precision and time resolution are compromised
Solution Approach 1:
The patent employs periodic clock signals for precise time measurement. The time detection circuit uses a first clock signal to detect a window period and a second clock signal with smaller period to detect sections within the window period. This periodic timing mechanism enables high-resolution time interval detection without mechanical components.
Solution Approach 2:
The patent creates multiple copies of the detection function through the sensor array's multiple rows and columns. Each row driver controls a row to output trigger signals, and the time detection circuit processes signals from multiple sensors in parallel. This replicated detection architecture achieves high measurement precision through simultaneous multi-point detection rather than sequential mechanical scanning.
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 solution enables precise distance measurement and improves durability by eliminating the need for mechanical rotation, making the ranging device more compact, cost-effective, and suitable for diverse applications.
Implementation Method 1
a sensor array including a plurality of sensors each sensing reflected light from object irradiated by a light source
Implementation Method 2
a sensor array including a plurality of sensors each sensing reflected light
Implementation Method 3
a time detection circuit configured to detect time interval when reflected light arrives at the plurality of sensors since the object is irradiated by using the plurality of trigger signals
Data Source
AI summary
A ranging device includes a sensor array including a plurality of sensors each sensing reflected light from object irradiated by a light source; a row driver configured to control the sensor array row by row to output a plurality of trigger signals; and a time detection circuit configured to detect time interval when reflected light arrives at the plurality of sensors since the object is irradiated by using the plurality of trigger signals, wherein the time detection circuit performs a first operation to detect a window period where a trigger signal is activated by using a trigger signal and a first clock signal, and performs a second operation to detect a section where the trigger signal is activated among a plurality of sections that divides the window period by using a second clock signal having smaller period than a period of the first clock signal.