ToF Sensor Flicker Frequency Estimation

Solution Overview

Problem

Current cell phones face challenges in estimating flicker frequency of artificial light sources without increasing acquisition cost, size, and complexity by integrating dedicated ambient light sensors.

Innovation Solution

Utilizing a time-of-flight sensor to estimate flicker frequency through spectral analysis, obtaining a profile of the light signal, and deducing the flicker frequency, without the need for a dedicated ambient light sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a dedicated ambient light sensor is integrated to estimate flicker frequency, then the flicker frequency estimation capability is improved, but the acquisition cost, size, and complexity of the device increase

Engineering Contradiction:

Improveflicker frequency estimation capabilityVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The time-of-flight sensor, originally designed for distance measurement, is made multi-functional by enabling it to perform both distance measurement and flicker frequency estimation. The sensor uses its photodetector to capture light signals for time-of-flight calculations and simultaneously captures ambient light variations to estimate flicker frequency through spectral analysis, eliminating the need for a separate ambient light sensor

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the flicker frequency estimation function into the existing time-of-flight sensor module. By combining the light detection capabilities of the time-of-flight sensor with spectral analysis algorithms, the system integrates multiple functions (distance measurement and flicker detection) into a single sensor unit, reducing overall device complexity and component count

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If a dedicated ambient light sensor is integrated to estimate flicker frequency, then the flicker frequency estimation capability is improved, but the acquisition cost increases

Engineering Contradiction:

Improveflicker frequency estimation capabilityVSAvoidacquisition cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The time-of-flight sensor is designed to perform multiple functions including distance measurement and flicker frequency estimation. By making the sensor universal, the system eliminates the need to manufacture devices with separate ambient light sensors, thereby reducing acquisition costs while maintaining flicker frequency estimation capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The time-of-flight sensor serves itself by using its own photodetector and light detection capabilities to perform flicker frequency estimation. The sensor leverages its existing hardware resources (photodetector, signal processing circuitry) to additionally detect ambient light variations, eliminating the need for separate dedicated sensors and reducing manufacturing costs

Inventive Principle:

Principle #25Self-service

3Measurement precision

If a dedicated ambient light sensor is integrated to estimate flicker frequency, then the flicker frequency estimation capability is improved, but the size of the device increases

Engineering Contradiction:

Improveflicker frequency estimation capabilityVSAvoiddevice size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The time-of-flight sensor is designed to perform multiple functions including distance measurement and flicker frequency estimation. By making the sensor universal, the system eliminates the need to manufacture devices with separate ambient light sensors, thereby reducing acquisition costs while maintaining flicker frequency estimation capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the flicker frequency estimation function into the existing time-of-flight sensor module. By combining the light detection capabilities of the time-of-flight sensor with spectral analysis algorithms, the system integrates multiple functions (distance measurement and flicker detection) into a single sensor unit, reducing overall device complexity and component count

Inventive Principle:

Principle #5Merging (Combining)

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 allows for effective estimation of flicker frequency, reducing the need for additional sensors and thereby decreasing the cost, size, and complexity of electronic devices.

Implementation Method 1

the luminance measurements are performed by a photodetector of the time-of-flight sensor

Methodology Applied

Scientific EffectPhotodetection: Photoelectric Effect

Implementation Method 2

the estimation of the flicker frequency is performed by spectral analysis

Methodology Applied

Scientific EffectSpectral analysis:

Data Source

PatentUS12298396B2Flicker frequency estimate

Publication Date: 2025.05.13 STMICROELECTRONICS (GRENOBLE 2) SAS

AI summary

A method for estimating a flicker frequency of a light source includes: obtaining, with a time-of-flight sensor, a profile of a light signal emitted by a light source; performing spectral analysis on the profile of the light signal emitted by the light source; and estimating a flicker frequency of the light source based on the spectral analysis of the profile of the light signal emitted by the light source.