Dimmable Luminary with Dynamic Color Transition
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Solution Overview
Problem
State-of-the-art wake-up lamps fail to simulate the natural color change of sunrise, resulting in an unnatural perception for users, as they only vary light intensity without changing chromaticity, which is crucial for mimicking the deep red to yellowish white transition associated with dawn.
Innovation Solution
A wake-up lamp with a defined chromaticity path that starts at a correlated color temperature between 400 K and 1500 K and ends above 2700 K, accompanied by a specific relationship between correlated color temperature and brightness, ensuring that each intensity step corresponds to a larger color temperature step than a reference black body radiator, thereby creating a more natural color development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light intensity is increased to simulate sunrise, then the wake-up lamp can wake users up effectively, but the color remains constant and appears unnatural
Solution Approach 1:
The light source is divided into multiple independent LED channels with different color temperatures (e.g., warm white, neutral white, cool white). Each channel can be controlled independently to achieve smooth color transitions while maintaining overall intensity control for effective wake-up function.
Solution Approach 2:
The chromaticity path is dynamically adjusted based on the light intensity level. As the intensity increases to simulate sunrise, the color temperature automatically shifts from warm to cool tones, creating a dynamic color transition that mimics natural dawn while maintaining the wake-up effectiveness.
2Device complexity
If a simple power increase is used to vary light intensity, then the device complexity is reduced, but the color change does not match natural sunrise perception
Solution Approach 1:
The control device dynamically adjusts multiple parameters simultaneously - both the intensity and the color temperature of the light output. By coordinating these parameter changes according to a predefined chromaticity path, the system achieves natural sunrise simulation without requiring overly complex hardware, using software control to manage the multi-parameter transition.
3Measurement precision
If the chromaticity path follows the black body line, then the color change is physically accurate, but the perceived naturalness is insufficient according to human perception
Solution Approach 1:
The chromaticity path is optimized for specific regions of the CIE diagram corresponding to sunrise conditions. Instead of following the entire black body line, the path is locally adjusted to match human perception of dawn - emphasizing the warm red-orange tones at low intensity and transitioning to yellow-white at higher intensity, creating a more natural perceived experience.
Data Source
AI summary
A wake-up lamp system (100; 1000) comprises: a light source (130) having a nominal light output intensity (Lmax); and a control device (110) for controlling the light source, the control device receiving a clock signal from a clock device (120). The control device, when operating in a wake-up mode, controls the light source such that its light output intensity is gradually increased from a minimum intensity value (Lmin) to a maximum intensity value (Lmu) and such that the color point of the light output is gradually changed to travel a predefined chromaticity path, with the position of the color point on said chromaticity path being set as a function of the light output intensity. Said chromaticity path has a starting point having a color temperature between 400K and 1500K associated with the minimum intensity and an end point having a color temperature higher than 2700K associated with the nominal intensity.