LED Lighting Control Using Averaged Ambient Light Sampling
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Solution Overview
Problem
Existing LED lighting systems face issues with flicker due to inconsistent ambient light levels, which are not accurately measured by integrated light sensors sampling in short time periods, leading to fluctuations in LED intensity adjustments.
Innovation Solution
A lighting apparatus with a light detection system that samples ambient light levels at multiple times during a survey period, averaging these levels to adjust LED intensity smoothly and consistently, reducing the impact of temporary light fluctuations from sources like neon lights, televisions, and natural light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If ambient light levels are sampled in very short time periods while LEDs are turned off, then the system can detect ambient light using integrated sensors, but the sampled light levels become inconsistent and lead to flicker
Solution Approach 1:
The system performs preliminary sampling of ambient light levels at multiple time points before making intensity adjustments. By collecting light level data over an extended period and calculating averages, the system prepares reliable baseline information that prevents reactive flickering responses to temporary light fluctuations.
Solution Approach 2:
The system implements feedback by continuously monitoring ambient light levels and using this information to adjust LED intensity. The feedback loop incorporates temporal averaging to filter out noise, ensuring that intensity adjustments are based on sustained ambient light conditions rather than transient fluctuations.
2Device complexity
If light sensors are integrated within the lighting fixture, then the system complexity is reduced, but the light from the fixture dominates the sensor detection making ambient light measurement difficult
Solution Approach 1:
The system uses periodic action by operating LEDs in duty cycles with distinct on and off periods. During the off periods, the integrated light sensor can detect ambient light levels without interference from the fixture's own LED output. This temporal separation allows the sensor to accurately measure ambient light despite being co-located with the light source.
Solution Approach 2:
The system performs preliminary sampling of ambient light levels during LED off-periods before making intensity adjustments. By collecting light level data in advance during periods when the LEDs are not emitting light, the system obtains accurate ambient light measurements that inform subsequent intensity control decisions.
3Speed
If LED intensity is adjusted frequently based on instantaneous light level readings, then the system responds quickly to ambient light changes, but perceivable flicker increases
Solution Approach 1:
The system performs preliminary sampling of ambient light levels over an extended period and calculates average values before making intensity adjustments. This preliminary data collection and averaging process filters out transient fluctuations, ensuring that intensity changes are based on sustained ambient light conditions rather than momentary variations.
Solution Approach 2:
The system maintains continuous monitoring of ambient light levels while using temporal averaging to smooth the control signal. This continuous action with filtered feedback ensures responsive yet stable LED intensity control that avoids perceivable flicker by not reacting to brief light level variations.
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 minimizes flicker by averaging ambient light levels over a longer period, providing a more stable and consistent LED intensity adjustment, improving user experience by reducing perceivable fluctuations in lighting.
Implementation Method 1
a light detection apparatus operable to sense light levels local to the lighting apparatus
Data Source
AI summary
The present invention is directed to lighting apparatus and methods for controlling lighting apparatus using ambient light levels. A controller within a lighting apparatus is used to activate and deactivate one or more light radiating devices within a duty cycle. In a first stage, the controller uses a light detection apparatus to sample the ambient light level at a plurality of sampling times during which the light radiating devices are deactivated. The light level when the light radiating devices are deactivated is an indication of the ambient light levels within the surrounding area of the lighting apparatus. The sampling times occur in different duty cycles within a survey time period. The controller determines an average for the light levels sampled over the survey time period, thus generating an averaged ambient light level over the survey time period. In a second stage, the controller adjusts an intensity of the light radiating devices based at least partially upon the averaged ambient light level. The controller may generate a target light level using the averaged ambient light level over the survey time period and a desired light level and, over an adjustment time period, incrementally adjust the intensity of the light radiating devices towards the target light level.