Notch Filter LED Circadian Lighting Spectral Control
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Solution Overview
Problem
Current LED lighting products lack the ability to control circadian stimulation levels effectively while maintaining desirable light quality aspects such as correlated color temperature (CCT) and color rendering index (CRI), and often fail to adapt to diurnal or circadian cycles, leading to potential health issues.
Innovation Solution
The use of filters, specifically designed notch and dichroic filters, to modify the spectral power distribution of LED light sources, reducing circadian stimulation while maintaining a CRI above 80 and CCT within a prescribed range, through the implementation of an interchangeable retaining ring kit for LED lamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If blue-primary phosphor-converted white-emitting LEDs are used for illumination, then illumination efficiency and brightness are improved, but circadian stimulation increases to harmful levels
Solution Approach 1:
The patent extracts and removes the harmful blue wavelength component (480-500nm) from the LED spectrum using a notch filter, while preserving the useful illumination wavelengths. This selective extraction allows maintaining brightness while eliminating circadian disruption.
Solution Approach 2:
The patent introduces an optical filter as an intermediary component between the LED light source and the human eye. This mediator selectively transmits beneficial wavelengths while blocking harmful blue light, resolving the contradiction between illumination and circadian stimulation.
2Object-affected harmful factors
If filters are added to reduce circadian stimulation, then circadian response is reduced, but light quality aspects such as CRI and CCT may deteriorate
Solution Approach 1:
The patent applies local quality by designing a filter with a narrow notch specifically targeted at the harmful blue wavelength range (480-500nm), while maintaining high transmission in other wavelengths critical for color rendering. This localized filtering preserves overall light quality while addressing circadian stimulation.
Solution Approach 2:
The patent changes the spectral parameters of the LED light by introducing a filter with specific transmission characteristics. The filter is designed with a narrow bandwidth notch that modifies only the harmful portion of the spectrum, preserving CRI above 80 and maintaining CCT within acceptable ranges.
3Object-affected harmful factors
If conventional filters are used to block blue light, then circadian stimulation is reduced, but chromatic shifts and color distortion increase
Solution Approach 1:
The patent segments the spectrum into distinct wavelength regions and applies selective filtering only to the harmful blue segment (480-500nm). This segmentation approach allows blocking circadian-disrupting wavelengths while preserving the spectral shape and color characteristics of other regions.
Solution Approach 2:
Instead of using a broad-spectrum filter that blocks all blue light and causes color distortion, the patent inverts the approach by using a narrow-band notch filter that blocks only the specific harmful wavelengths while maintaining the natural spectral distribution of the rest of the light.
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 allows for varying levels of circadian stimulation control while preserving light quality, reducing circadian response by up to two orders of magnitude and minimizing chromatic shifts, thus providing a more effective and safer lighting solution.
Implementation Method 1
at least one filter; the first emission is configured to be filtered by the filter
Implementation Method 2
at least one first LED emission source characterized by a first emission; at least one second LED emission source characterized by a second emission
Data Source
AI summary
A light source comprising: (a) An LED source comprising at least one LED emitting an LED emission and at least one wavelength-converting material configured to convert a fraction of the LED emission, the LED source emitting a primary SPD; and (b) at least one optical element configured to interact with the primary SPD to remove radiation in the primary SPD, such that a final SPD is emitted from the light source; wherein a fraction of the primary SPD in the wavelength range 430-500 nm is less than 5%; and a fraction of the final SPD in the wavelength range 430-500 nm is less than 1%.