TOF Distance Sensor Signal Integration for Extended Range
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Solution Overview
Problem
Current distance measurement devices using the Time Of Flight (TOF) method face limitations in measuring distances beyond a certain range, particularly for far-away objects, as they struggle to accurately detect and process the reflected light pulses effectively.
Innovation Solution
The proposed solution involves a distance sensor and image sensor configuration that includes a controller, light receiver, signal change detector, and time measurement section, where a light source emits a first light pulse, and the light receiver generates a signal charge from the reflected light pulse, allowing for accurate measurement of the time interval between the emission and reception of the light pulse, thereby extending the measurable distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional TOF distance measurement devices are used, then they can measure distances within a limited range, but they fail to accurately detect and process reflected light pulses from far-away objects
Solution Approach 1:
The patent applies preliminary action by performing signal integration over multiple light pulse periods before final detection. The signal change detection unit integrates the output signal from the photodiode over a predetermined period, accumulating signal energy from reflected light pulses before processing. This preliminary integration enhances the detectability of weak reflected signals from distant objects, enabling accurate distance measurement beyond conventional ranges while maintaining measurement precision.
Solution Approach 2:
The patent introduces an intermediary signal processing mechanism between light reception and distance calculation. The signal change detection unit acts as an intermediary that converts the raw photodiode output into an integrated signal representing light pulse timing. This intermediary processing stage enhances the signal-to-noise ratio and enables accurate timing detection of reflected light pulses from far-away objects, resolving the contradiction between extended range and measurement accuracy.
2Length of stationary object
If the light receiver stores signal charge and converts it to voltage, then the measurable distance is extended, but the device complexity increases
Solution Approach 1:
The patent merges multiple functions into integrated units to reduce overall device complexity. The signal change detection unit combines the photodiode, signal storage capacitance, and voltage conversion functionality into a single integrated circuit block. By merging these components, the patent achieves extended measurable distance through signal charge storage and voltage conversion while minimizing the increase in device complexity through functional integration rather than separate discrete components.
Solution Approach 2:
The light receiver is designed with multi-functionality to handle various signal processing tasks within a single unit. It can store signal charge, convert to voltage, and output signals for distance measurement, serving multiple purposes simultaneously. This universal design approach extends measurable distance while avoiding the need for multiple separate components, thereby controlling device complexity.
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 the measurement of distances up to 30 meters to 120 meters with high accuracy by effectively detecting the signal change and converting it into a measurable time interval, enhancing the device's range and precision.
Implementation Method 1
a photodiode that generates signal charge by receiving a light pulse
Data Source
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Figure 3(A)~4
Figure 5
AI summary
A distance sensor according to an embodiment of the present disclosure includes: a controller that instructs a light source section to emit a first light pulse; a light receiver that includes a photodiode which causes a signal charge to be generated by receiving a first reflected light pulse corresponding to the first light pulse, and generates a light reception signal by storing the signal charge and converting the signal charge into a voltage; a signal change detector that performs a first detection operation of detecting a first signal change corresponding to the first reflected light pulse in the light reception signal; and a time measurement section that performs, on a basis of the first signal change, a first measurement operation of measuring a first time interval from an emission timing of the first light pulse in the light source section to a reception timing of the first reflected light pulse in the light receiver.