Multi-Source TOF Range Finder With Shifted Emission Timings
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Solution Overview
Problem
Conventional range finders using the time of flight (TOF) method have limitations in capturing images with a wider angle of view due to light diffusion and reduced light intensity, leading to shorter measurable distances and increased power consumption.
Innovation Solution
The range finding device employs multiple light sources and TOF sensors with shifted light emission timings to avoid overlapping and reduce peak power consumption, while maintaining accurate distance measurement and expanding the angle of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the irradiation range is set wider corresponding to the wider angle of view, then the angle of view is improved, but the amount of light per unit solid angle decreases and the measurable distance becomes shorter
Solution Approach 1:
The patent divides the single wide-angle irradiation into multiple segmented light emission units, each covering a specific angular range. By segmenting the light sources and their corresponding reception units, the system maintains higher light intensity in each segment while achieving overall wide-angle coverage through combination of multiple segments.
2Measurement precision
If the brightness of the light source is increased to counteract light diffusion, then the measurable distance is improved, but the power consumption of the light source increases
Solution Approach 1:
Instead of using one high-power light source, the patent segments the illumination into multiple lower-power light sources, each targeting a specific angular sector. This segmentation allows each light source to operate at lower brightness while collectively covering the same field of view, thereby reducing total power consumption.
3Adaptability or versatility
If a plurality of sets of light emitting unit and sensor unit is used to capture image at the same time, then the angle of view is improved, but one set may receive reflection light from another set and the range finding accuracy deteriorates
Solution Approach 1:
The patent implements periodic time-division multiplexing where multiple light emitting units operate in alternating time slots rather than simultaneously. Each light emitting unit emits light during its designated time period, and the corresponding sensor unit receives reflections only during that specific time window, eliminating cross-interference between channels.
4Adaptability or versatility
If the light emission timings of two light sources overlap, then the angle of view coverage is improved, but the peak power consumption increases and sufficient power may not be supplied
Solution Approach 1:
The patent employs periodic time-division operation where light sources are activated in sequential time slots rather than overlapping simultaneously. This periodic activation ensures that peak power consumption of individual light sources does not叠加 (superimpose), keeping the overall power demand within the battery's supply capability while still achieving complete angular coverage through the sequence of operations.
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 effectively reduces peak power consumption, improves the accuracy of range finding, and allows for a wider angle of view without compromising the measurable distance.
Implementation Method 1
the time of flight (TOF) method can be used as one method of finding a range from an imaging device to an object, in which an irradiation or projection light is emitted to the object and a reflection light coming from the object is received, and then a range or distance to the object is calculated using a time difference between a time of emitting the irradiation or projection light and a time of receiving the reflection light
Data Source
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AI summary
A range finding device (1, 1a, 1b, 1c) includes a plurality of light sources (11a, 11b), each configured to emit irradiation light to an object; a plurality of light reception units (16a, 16b, 18a, 18b) configured to receive reflection light coming from the object when the irradiation light hits and reflects from the object, the number of plurality of light reception units (16a, 16b, 18a, 18b) being the same number of the plurality of light sources (11a, 11b); an operation control unit (111) configured to shift light emission timing of at least one or more light sources among the plurality of light sources (11a, 11b); and a measurement unit (132) configured to calculate a distance to the object based on information output from each of the plurality of light reception units (16a, 16b, 18a, 18b).