Distance Measuring Device Using Self-Calibrating Light Pulse Timing
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Solution Overview
Problem
Existing distance measuring devices are not accurate enough for security and automotive applications due to synchronization errors and variations caused by environmental factors like supply voltage and temperature, which current calibration methods do not fully compensate for.
Innovation Solution
A method and apparatus that determine the distance by measuring the current through or voltage across a light emitting component to identify specific threshold points, integrating the intensity of reflected light between these points, and using these measurements to calculate the distance using formulas involving the time intervals and light velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration tables stored in memory are used to compensate for environmental variations, then some accuracy improvement is achieved, but the device complexity increases and implementation costs time, effort and money
Solution Approach 1:
The system automatically measures the actual light pulse length and timing parameters directly from the emitted pulse, eliminating the need for external calibration tables or manual adjustment. The device self-calibrates by detecting its own pulse characteristics through the light sensor and processing circuitry, reducing implementation complexity while maintaining accuracy across environmental variations.
2Ease of operation
If digital pulse synchronization is used to generate light pulses, then the distance measuring device can operate, but synchronization errors and pulse length variations are introduced due to environmental parameters
Solution Approach 1:
The system uses a light sensor to detect the actual emitted light pulse and feeds this information back to the processing circuitry. The processing circuitry then uses this feedback to accurately determine the pulse length and timing, compensating for environmental variations and synchronization errors without requiring manual intervention.
Solution Approach 2:
The patent replaces reliance on digital pulse synchronization (electronic/mechanical timing system) with optical measurement. By using the light sensor to detect the actual light pulse characteristics and processing this optical information, the system achieves higher accuracy independent of electronic synchronization errors and environmental parameter drift.
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 approach provides more accurate distance measurements by directly assessing the emitted light pulse length and its starting time, reducing errors associated with environmental variations and improving precision for security and automotive applications.
Implementation Method 1
sending a pulse of light from a light emitting component to said object by means of passing a current pulse sent through said component
Implementation Method 2
receiving a reflected pulse of light from said object at said unit by a light sensor
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An apparatus for determining the distance (d) from a unit (50) to an object (24) comprises means to send a pulse of light (62) from a light emitting component (60) to said object (24) bypassing a current pulse (I1) through said component (60); means to measure the current (I1) through or voltage across said light emitting component (60) and to determine the point T0 when this values achieves a pre-determined first threshold value THL1 and determining the point T1 when this values is reduced to a pre-determined second threshold value THL2; means to using the time point T1 to define two time windows; means to receive a reflected pulse of light (32) from said object (24) at said unit (50) by a light sensor (26); means to integrate a measure of the intensity of reflected light (32) in said light sensor (26) during the two time windows to provide two values (Q1/Q3 and Q2/Q4); means to determine the time of flight from the two values (Q1/Q3 and Q2/Q4), the difference between T0 and T1 (T1-T0) and the speed of light, c.