Multi-Group PWM Light Fixture for High-Resolution Dimming
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Solution Overview
Problem
Existing light fixture systems have limited ability to achieve smaller intensity steps between minimum non-zero and zero intensity, leading to discrete and noticeable changes in light output.
Innovation Solution
A light fixture system with multiple groups of light sources controlled via pulse-width modulation (PWM), where groups are repeatedly switched on and off in rapid succession to maintain a constant average intensity, with switching periods shorter than 1/10 seconds, allowing for smoother intensity transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pulse-width modulation (PWM) is used to control light intensity, then the light intensity can be dimmed, but the minimum intensity is finite and larger than zero due to the finite period of minimum pulse width
Solution Approach 1:
The light fixture system divides the light sources into multiple independently controllable groups. By controlling different groups with different PWM duty cycles or phase shifts, the system achieves finer intensity resolution than would be possible with a single PWM channel, effectively segmenting the intensity control into multiple manageable levels.
Solution Approach 2:
The system uses periodic PWM modulation with carefully selected frequencies and duty cycles. By operating at frequencies above the human visual detection threshold and using complementary duty cycles across multiple groups, the system achieves smooth intensity transitions without visible flicker or discrete steps.
2Ease of operation
If the minimum pulse width is kept finite for technical reasons, then the control is simplified, but the discrete step between minimum non-zero intensity and zero intensity becomes noticeable
Solution Approach 1:
The system merges multiple PWM-controlled light groups to create a composite output. By combining the outputs of multiple groups with different duty cycles or phase relationships, the system achieves continuous intensity transitions while maintaining the technical simplicity of finite PWM control for each individual group.
Solution Approach 2:
The system dynamically adjusts the PWM duty cycles and phase shifts of different light groups based on the desired intensity level. This dynamic control allows the system to maintain smooth transitions across the entire intensity range while keeping each individual PWM channel simple and manageable.
3Illumination intensity
If groups are switched on and off rapidly with PWM, then the average intensity can be maintained constant, but the switching frequency must be high enough to be imperceptible to human eye and cameras
Solution Approach 1:
The system uses feedback mechanisms to monitor and adjust the PWM switching parameters. By detecting the actual light output and comparing it with the desired intensity level, the controller dynamically adjusts the duty cycles and phase shifts to maintain constant average intensity while ensuring the switching remains imperceptible to human observers and cameras.
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
Enables finer dimming resolution and homogeneous light output perception, making intensity changes imperceptible to the human eye and cameras, while maintaining stable light emission over time.
Implementation Method 1
the intensity of each group of light sources is controlled via pulse-width modulation, PWM
Data Source
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AI summary
A light fixture system comprising a light fixture comprising light sources arranged in groups, wherein each group comprises one or more light sources, and a controller, wherein the controller is arranged to control the groups so that each of the groups is repeatedly switched on and off, wherein at a first point in time some groups are switched on and others are switched off, at a second point in time some of the groups which were switched on at the first point in time are switched off, and some of the groups which were switched off at the first point in time is switched on, and at a third point in time some of the groups which were switched on at the second point in time are switched off, and some of the groups which were switched off at the second point in time are switched on.