Time-of-Flight Sensor Synchronization Circuit for Light Timing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing time-of-flight sensors face synchronization issues between the emission and reception of light signals due to spatial separation and temperature variations, leading to measurement errors and increased complexity with additional components like optical barriers and calibration tables.

Innovation Solution

A method and device for synchronizing the emission and reception of light signals by controlling the duration of synchronization and power signals using a feedback loop and delay-locked loops to ensure identical development and transmission times, incorporating a power control circuit and switching means to synchronize the light source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a second pixel array and optical barrier are added to synchronize emission and reception, then synchronization accuracy is improved, but device complexity and silicon area increase

Engineering Contradiction:
Improvesynchronization accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the synchronization function from the pixel arrays and optical barrier, implementing it through a dedicated synchronization circuit that processes control signals. This separates the synchronization task from the main imaging functionality, reducing the complexity of the pixel array structure while maintaining synchronization accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a synchronization circuit as an intermediary component that receives control signals and generates synchronized emission and reception commands. This intermediary mechanism eliminates the need for complex optical barriers and additional pixel arrays, achieving synchronization through electronic signal processing instead.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If calibration tables are used to synchronize transmitting and receiving devices, then synchronization is achieved, but distance measurement quality degrades

Engineering Contradiction:
Improvesynchronization accuracyVSAvoiddistance measurement quality
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the synchronization circuit continuously monitors and adjusts the timing of emission and reception signals based on actual system performance. This dynamic feedback approach eliminates the need for static calibration tables, maintaining high distance measurement quality while achieving accurate synchronization.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If additional components are added to generate return signals and improve synchronization, then synchronization accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvesynchronization accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent designs the synchronization circuit to perform multiple functions: it processes control signals, generates emission commands, triggers reception, and maintains timing synchronization all within a single integrated component. This multi-functionality eliminates the need for separate dedicated components for each function, reducing overall device complexity while maintaining high synchronization accuracy.

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

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 synchronizes the transmission and reception of light signals effectively, reducing measurement distortions and simplifying the sensor design without degrading distance value quality.

Implementation Method 1

a device for receiving the emitted signal reflected on an obstacle

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

The reflected signal processed by the receiving device makes it possible to determine the distance

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

transmitting a synchronization signal to a device for emitting the light signal, the synchronization signal being developed from the control signal

Methodology Applied
Scientific EffectElectrical signal transmission: Conduction (electrical)

Implementation Method 4

a device for emitting a light signal, generally a laser

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Data Source

PatentEP3865901B1Synchronisation device, associated flight time sensor and method
Publication Date: 2025.10.15 STMICROELECTRONICS (GRENOBLE 2) SAS
  • EP3865901B1 patent drawingFigure 1~2
  • EP3865901B1 patent drawingFigure 3~4

AI summary

The device (DISP) for synchronizing the transmission and reception of a light signal for a time-of-flight sensor (1) includes a power control circuit (8) configured to generate and transmit a power signal (S2) from a control signal (S1) of the sensor, the power signal being configured to power a pixel array (9) of the sensor, a synchronization signal processing module (10) configured to process the synchronization signal (S3) from the control signal and a switching means (19) configured to power a light source (11) of a light signal transmission device (3), the processing module being further configured to transmit the synchronization signal by switching means such that the processing and transmission time of the synchronization signal and the generation and transmission time of the power signal are identical.