Dual Sensor Ambient Light Detection with Bypass Switch

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Solution Overview

Problem

Existing systems face challenges in accurately detecting ambient light levels in environments with pulsating light sources due to interference from the light source itself, leading to suboptimal power consumption and flickering issues.

Innovation Solution

A dual-sensor system is employed, where a first light sensor generates a signal during both on and off periods of the light source, and a second sensor, configured as a dark diode, compensates for dark current to provide an accurate ambient light measurement by subtracting its signal from the first sensor's signal, with a bypass switch managing sensor operation to minimize transient periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the light sensor is placed near the light source to enable automated lighting adjustment, then the ability to adjust artificial lighting to match desired levels is improved, but the light source interferes with the sensor's ability to detect ambient light

Engineering Contradiction:

Improveautomated lighting adjustmentVSAvoidambient light detection accuracy

Core Design Contradiction:

Extent of automationVSMeasurement precision

Solution Approach 1:

The light source operates in pulsating cycles, turning on and off periodically. During the off-period, the light sensor can accurately detect ambient light levels without interference from the light source. The control system uses these periodic measurement opportunities to adjust lighting while maintaining desired illumination levels.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system performs ambient light measurement during the off-period of the light source cycle, before the light source turns on again. This preliminary measurement of ambient light conditions allows the system to pre-calculate the appropriate light output level needed, enabling smooth transitions and accurate lighting control.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If the light source is turned off frequently to allow accurate ambient light measurement, then measurement precision is improved, but flickering occurs and power consumption increases

Engineering Contradiction:

Improveambient light detection accuracyVSAvoidflickering

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The system implements regular pulsating cycles where the light source turns on and off at predetermined intervals. During the off-period, ambient light is measured accurately. This periodic operation allows the system to maintain precise ambient light detection while controlling the duration and frequency of off-periods to minimize visible flickering.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The control system adjusts the duty cycle parameters of the pulsating light source, optimizing the ratio of on-time to off-time. By carefully controlling the duration of off-periods for measurement while maintaining sufficient on-time for illumination, the system achieves accurate measurements without excessive flickering or power consumption.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the light source operates continuously to maintain illumination, then productivity is improved, but the light source continuously interferes with ambient light detection

Engineering Contradiction:

Improveillumination continuityVSAvoidambient light detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The light source operates in pulsating cycles with predetermined on and off periods. During the off-period, the light sensor can accurately detect ambient light levels without interference. The system maintains overall illumination by quickly transitioning between states and using the measurement data to control light output, thereby preserving productivity while enabling accurate detection during measurement windows.

Inventive Principle:

Principle #19Periodic action

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 precise ambient light detection, reducing flickering and improving power adjustment accuracy across varying light conditions, ensuring optimal lighting levels while minimizing energy consumption.

Implementation Method 1

A first light sensor is configured to generate a first signal based on an amount of light detected in the volume

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

A second sensor is configured to generate a second signal based on an environment in the volume

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS10281324B1Systems and methods for determining ambient illumination having dual sensors controlled by a bypass switch

Publication Date: 2019.05.07 SIGNIFY NORTH AMERICA CORP

AI summary

Systems and methods are provided for measuring an ambient light level in a volume that is lighted by a pulsating light source. A first light sensor is configured to generate a first signal based on an amount of light detected in the volume. A bypass switch is configured to bypass the first light sensor at a first point in time when the light source is on and to not bypass the first light sensor at a second point in time when the light source is off. A second sensor is configured to generate a second signal based on an environment in the volume, and a difference circuit is configured to determine a difference magnitude between the second signal and the first signal to generate an ambient light signal.