Timing Synchronization Circuit for Phase-Modulated Light Detection

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Solution Overview

Problem

Existing spatial information detection systems using intensity-modulated light face errors due to variations in ambient temperature and humidity, affecting the accuracy of distance and reflectivity measurements.

Innovation Solution

A spatial information detection apparatus with a timing synchronization circuit that adjusts the phase of intensity-modulated light emitted and received to maintain a constant phase difference, using phase comparators and phase adjusting circuits to synchronize the light-emitting and light-receiving elements, and a current controller to stabilize the light-receiving element's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If intensity-modulated light is used for detecting spatial information, then measurement capability is provided, but measurement precision deteriorates due to variations in ambient temperature and humidity

Engineering Contradiction:
Improvespatial information measurement accuracyVSAvoidmeasurement stability under environmental changes
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism through the timing synchronization circuit that continuously monitors the phase difference between emitted and received intensity-modulated light, and automatically adjusts the timing signals to maintain optimal synchronization. This feedback loop compensates for environmental variations in temperature and humidity, ensuring stable measurement precision without requiring manual recalibration.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the timing parameters of the light-emitting and light-receiving elements dynamically based on environmental conditions. The timing synchronization circuit adjusts the phase and timing of signals in real-time to compensate for environmental variations, thereby maintaining measurement accuracy despite changes in ambient temperature and humidity.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If timing synchronization is implemented to maintain constant phase difference, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvephase difference synchronization accuracyVSAvoidtiming synchronization circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The timing synchronization circuit is designed to perform multiple functions: it generates timing signals for both the light-emitting element and the light-receiving element, monitors phase differences, and automatically adjusts synchronization. By consolidating these functions into a single multi-functional circuit, the patent reduces overall device complexity while maintaining high measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The timing synchronization circuit is self-adjusting and automatically maintains optimal synchronization without external intervention. It monitors its own performance through phase difference detection and self-corrects timing variations, eliminating the need for complex external control systems or manual calibration procedures.

Inventive Principle:
Principle #25Self-service

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 solution ensures accurate measurement of spatial information by maintaining synchronization between the light-emitting and light-receiving elements despite environmental changes, improving detection accuracy and reducing errors.

Implementation Method 1

a light-emitting element (100) that emits an intensity-modulated light to a target space

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 2

When using the intensity-modulated light of a sinusoidal waveform, the light reflected from the object is also of a sinusoidal waveform with a phase difference

Methodology Applied
Scientific EffectIntensity modulation: Phase Modulation

Implementation Method 3

a light-receiving element (200) that receives the intensity-modulated light reflected from an object in the target space

Methodology Applied
Scientific EffectLight reception: Photoelectric Effect

Implementation Method 4

a timing synchronization circuit (70) that maintains a constant phase difference between a phase of an intensity-modulated light from the light-emitting element and a phase of a timing signal for the light-receiving element

Methodology Applied
Scientific EffectPhase synchronization: Phase Modulation

Data Source

PatentEP1944622B1Spatial information detecting device
Publication Date: 2013.04.10 PANASONIC HOLDINGS CORP
  • EP1944622B1 patent drawingFigure 1
  • EP1944622B1 patent drawingFigure 2
  • EP1944622B1 patent drawingFigure 3

AI summary

In an apparatus using an intensity-modulated light for detection of spatial information based upon light intensity of light reflected from a target space, a timing synchronization circuit is provided to synchronize a phase of the intensity-modulated light from a light-emitting element with a timing of operating a light-receiving element receiving the intensity-modulated light. The light-receiving element is caused to operate for enabling the detection of intensity of the received light for each of a plurality of phase regions within one cycle of the intensity-modulated light. The timing synchronization circuit functions to compare a cyclic variation determining the operation of the light-receiving element with a cyclic variation associated with an output from a light-emitting element driving circuit in order to keep a constant phase difference between these two cyclic variations.