Distance Measurement Device Phase Control Pulse

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Solution Overview

Problem

Conventional distance measurement devices face challenges in achieving high resolution and accuracy due to the difficulty in generating pulse waveforms with pulse widths less than 100 psec and modulation frequencies higher than 3 GHz, which are required for precise distance detection.

Innovation Solution

A distance measurement device with a photoelectric conversion system that includes a light receiving unit, charge storage unit, charge discharge unit, and a controller that generates control pulse voltages with different phases to modulate and read charges, allowing for improved distance calculation based on the response characteristics of the light receiving unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the pulse width of the light source is shortened to improve distance resolution, then measurement precision is improved, but it becomes difficult to generate the pulse waveform with high accuracy

Engineering Contradiction:

Improvedistance resolutionVSAvoiddifficulty to generate pulse waveform

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The invention changes the parameter of pulse width to be sufficiently shorter than the response time of the light receiving unit. This parameter change allows the system to operate in a regime where the pulse characteristics do not need to be precisely controlled, as the sensor's response time becomes the dominant factor, thereby improving distance resolution without requiring difficult pulse generation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of trying to precisely control the light source pulse waveform to achieve high resolution, the invention inverts the approach by making the pulse sufficiently short that the sensor's inherent response characteristics become the determining factor. This reverses the control burden from the light source to the sensor, solving the manufacturing difficulty

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If the modulation frequency is increased to improve distance resolution, then measurement precision is improved, but it becomes difficult to supply the pulse signal for demodulation

Engineering Contradiction:

Improvedistance resolutionVSAvoiddifficulty to supply pulse signal

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The invention changes the modulation frequency parameter to be equal to or higher than three GHz, operating in a high-frequency regime where the pulse signal requirements become less stringent. This parameter change enables improved resolution while the system uses the impulse response characteristics to simplify the demodulation requirements

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If the pulse width is made sufficiently shorter than the response time of the light receiving unit, then distance resolution is improved, but the sensor response waveform deteriorates

Engineering Contradiction:

Improvedistance resolutionVSAvoidsensor response waveform

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The invention converts the potential harm of sensor response waveform deterioration into a benefit by deliberately using the impulse response characteristics of the light receiving unit. The response waveform, rather than being a problem to be eliminated, becomes the basis for accurate distance calculation through mathematical modeling and phase-based detection

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention introduces phase-based control pulse voltages as an intermediary mechanism. By using multiple phases of control pulses and analyzing the phase differences in the sensor response, the system can accurately determine distance while accounting for the sensor's response characteristics, thereby maintaining reliability despite the short pulse width

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enables distance detection with enhanced resolution and accuracy by controlling pulse light irradiation timing and applying phase-based control pulse voltages, reducing measurement inaccuracies caused by sensor response waveform deterioration.

Implementation Method 1

a light receiving unit for converting incident light into a charge

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS10132927B2Distance measurement device

Publication Date: 2018.11.20 NAT UNIV CORP SHIZUOKA UNIV

AI summary

A distance measurement device according to one aspect of the present invention includes a photoelectric conversion device which includes a light receiving unit, a charge storage unit, a charge discharge unit, and a gate electrode, a controller which controls an irradiation timing of pulse light having a pulse width which is sufficiently shorter than response time of the light receiving unit to an object and performs control to generate control pulse voltages having at least two kinds of phases based on the irradiation timing and to apply it to the gate electrode, a charge reading unit which reads a first and second charges stored in the charge storage unit according to the applications of the respective control pulse voltages having two kinds of phases as a first and second electrical signals, and a calculation unit which calculates a distance to the object based on the first and second electrical signals.