Distance Measuring Device Non-Coaxial Optical System
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Solution Overview
Problem
Conventional distance measuring devices using 2D sensors face challenges in achieving both long-distance ranging and a wide horizontal field of view, leading to trade-offs in effective aperture and angle resolution, and struggle with defocus issues that affect ranging accuracy, especially for short-distance targets.
Innovation Solution
The device employs a non-coaxial optical system with two light detection units optimized for different distances, one with a narrow field of view and large aperture for long-distance ranging and another with a wide field of view for short-distance ranging, using a common emission section and 2D sensors to improve resolution and reliability across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single optical system is used for both long-distance and short-distance ranging, then device complexity is reduced, but measurement precision deteriorates due to defocus issues and inability to optimize for different distance ranges
Solution Approach 1:
The patent divides the light receiving unit into multiple independent optical systems, each optimized for specific distance ranges. The first light receiving unit has an optical system optimized for long-distance ranging with larger aperture, while the second light receiving unit has an optical system optimized for short-distance ranging with smaller aperture. This segmentation allows each unit to achieve optimal measurement precision for its designated range without compromising the other.
Solution Approach 2:
The patent implements dynamic switching between different light receiving units based on the distance to the target object. The control unit determines which unit to activate based on detected distance information, allowing the system to adapt its optical configuration dynamically. This enables the system to maintain high measurement precision across varying distance ranges while managing device complexity through intelligent control.
2Measurement precision
If a large aperture optical system is used for long-distance ranging, then measurement precision is improved, but field of view narrows and short-distance ranging performance deteriorates
Solution Approach 1:
The patent segments the light receiving functionality into multiple units with different optical characteristics. The first light receiving unit uses a large aperture optical system specifically for long-distance ranging to achieve high measurement precision, while the second light receiving unit uses a smaller aperture optical system that provides a wider field of view for short-distance ranging. This segmentation allows the system to optimize for long-distance precision without sacrificing short-distance adaptability.
Solution Approach 2:
Each light receiving unit is designed with local quality optimized for its specific function. The first unit's optical system has large aperture characteristics locally optimized for collecting weak reflected light from distant targets, while the second unit's optical system has smaller aperture characteristics locally optimized for capturing a broader angular range of light from nearby targets. This local optimization resolves the contradiction between precision and field of view coverage.
3Adaptability or versatility
If a small aperture optical system is used for short-distance ranging, then field of view widens, but measurement precision deteriorates for long-distance targets
Solution Approach 1:
The patent segments the light receiving function into multiple specialized units. The second light receiving unit employs a small aperture optical system that provides a wide field of view, enabling it to effectively capture reflected light from short-distance targets across a broad angular range. The first light receiving unit employs a large aperture optical system specifically for long-distance ranging. This segmentation allows the small aperture unit to achieve wide field of view without compromising the long-distance precision capability of the other unit.
4Measurement precision
If multiple specialized optical systems are used for different distance ranges, then measurement precision is improved across all ranges, but device complexity increases
Solution Approach 1:
The patent merges multiple specialized light receiving units into a single integrated device with a unified control system. The control unit coordinates the operation of different light receiving units based on target distance, and the measurement unit integrates data from multiple units to produce comprehensive ranging information. This merging approach allows the system to achieve high measurement precision across all distance ranges while managing device complexity through integrated control and coordinated operation.
Solution Approach 2:
The patent implements dynamic control that adapts the active optical system based on real-time distance detection. The control unit switches between different light receiving units depending on the range to the target object, allowing the system to maintain optimal measurement precision dynamically. This dynamic operation reduces the effective complexity by ensuring that only the necessary optical subsystem is active at any given moment, rather than requiring all systems to operate simultaneously.
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 configuration enables highly reliable ranging from extremely short to long distances, addressing issues of angle resolution, defocus, and cost constraints by integrating ranging results from both units, providing fine resolution and a wide field of view while reducing costs and power consumption.
Implementation Method 1
The light source emits an optical signal... The first optical system is configured to guide a reflected light of the optical signal emitted from the light emitter to the first sensor
Implementation Method 2
The measurement section is configured to calculate a first distance value and a second distance value... The first distance value is calculated using a first time and a second time... The third time is a time at which the second sensor detects the reflected light
Implementation Method 3
The avalanche photodiode includes a P-type semiconductor layer and an N-type semiconductor layer... When a reverse bias is applied to the avalanche photodiode, a strong electric field is generated... an electron that collided with the atom ionizes the atom, and generates a new pair of an electron and a positive hole
Implementation Method 4
The first optical system is configured to guide a reflected light of the optical signal emitted from the light emitter to the first sensor... The second optical system is configured to guide the reflected light to the second sensor
Data Source
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Figure 3
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AI summary
A distance measuring device according to one embodiment includes a light emitter, a first light receiver, a second light receiver, a measurement section, and a controller. The light emitter includes a light source and a mirror. The light source emits an optical signal. The mirror reflects the optical signal. The first light receiver includes a first sensor and a first optical system. The first sensor includes first pixels. The first optical system is configured to guide a reflected light of the optical signal emitted from the light emitter to the first sensor. The second light receiver includes a second sensor and a second optical system. The second sensor includes second pixels. The second optical system is configured to guide the reflected light to the second sensor. The measurement section is configured to calculate a first distance value and a second distance value, wherein the first distance value is calculated using a first time and a second time, and the second distance value is calculated using the first time and a third time, and wherein the first time is a time at which the light source emits the optical signal, the second time is a time at which the first sensor detects the reflected light, and the third time is a time at which the second sensor detects the reflected light. The controller is configured to cause the light source to emit the optical signal intermittently and to control the mirror to perform scanning using the optical signal. The controller is further configured to set a first light-receiving area in which at least one first pixel among the first pixels is selectively turned on in the first sensor, and to set a second light-receiving area in which at least one second pixel among the second pixels is selectively turned on in the second sensor. The controller is further configured to determine a position of the first light-receiving area and a position of the second light-receiving area according to a state of the mirror when the optical signal is emitted.