White Light Lamp Brightness and CCT Control via Segmented Power Distribution
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Solution Overview
Problem
Existing lighting systems using TRIAC dimmers cannot effectively vary the brightness and correlated color temperature (CCT) of white light lamps in a controlled manner, as they primarily rely on thermal radiation and do not allow for independent adjustment of CCT and brightness.
Innovation Solution
A controller is used to distribute power to first and second light-emitting devices emitting white lights with different CCTs, adjusting their brightness and current based on segment duration of electrical supply power, allowing for varying CCT and brightness combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a TRIAC dimmer is used to adjust power to a white light lamp, then brightness can be adjusted, but correlated color temperature (CCT) cannot be independently controlled
Solution Approach 1:
The patent segments the white light emission into multiple light-emitting devices with different CCT characteristics. By independently controlling the power distribution to each device, the system can adjust both overall brightness and CCT separately, resolving the contradiction between brightness control and CCT adaptability.
Solution Approach 2:
Different portions of the lighting system (individual light-emitting devices) are assigned different CCT properties. The first device emits light at a first CCT while the second device emits at a second CCT, allowing local differentiation of light characteristics to achieve independent control of overall brightness and CCT.
2Illumination intensity
If power is reduced to decrease brightness, then illumination intensity decreases, but CCT also changes undesirably
Solution Approach 1:
The system changes the distribution parameters of power to multiple light-emitting devices rather than uniformly reducing power. By adjusting the ratio of power allocated to devices with different CCTs, the system can maintain constant CCT while varying total brightness, or independently control both parameters.
Solution Approach 2:
The power distribution scheme dynamically adjusts the proportion of power allocated to each light-emitting device based on the desired operating point. This dynamic reallocation allows the system to decouple the relationship between brightness and CCT that exists in conventional single-device systems.
3Adaptability or versatility
If multiple light-emitting devices with different CCTs are used, then independent control of brightness and CCT is enabled, but device complexity increases
Solution Approach 1:
The controller is designed to perform multiple functions: it manages power distribution to maintain constant combined power, regulates brightness levels, and controls CCT independently. This multi-functionality consolidates what would otherwise require separate control systems, offsetting the added complexity of having multiple light-emitting devices.
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 solution enables precise control over the combined CCT and brightness of white light emitted by the lamp, maintaining constant brightness in one range and constant CCT in another, while adjusting current and power distribution accordingly, enhancing user-adjustable lighting options.
Implementation Method 1
The first light-emitting device may comprise one or more LEDs, and the second light-emitting device may comprise one or more LEDs
Data Source
AI summary
A controller provides power to (i) a first light-emitting device that emits a first white light of a first correlated color temperature (CCT) and (ii) a second light-emitting device that emits a second white light of a second CCT lower than the first CCT. The first and second white lights mix to yield a combined white light having a combined-light CCT with a combined-light brightness. The controller receives electrical supply power in the form of segments of power. The controller distributes the supply power to the first and second light-emitting devices according to a power-distribution scheme that differentiates between whether segment duration of the segments is in an upper range or a lower range such that: (i) throughout the upper range: as segment duration decreases, combined-light CCT decreases and combined-light brightness remains substantially constant, and (ii) throughout the lower range: as the segment duration decreases, combined-light brightness decreases.