Optical Filter for Warm LED Light with High CRI
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Solution Overview
Problem
Solid state lighting technologies face challenges in achieving high color rendering index (CRI) and warm color temperature simultaneously, particularly in the range of 2700K to 4000K, which is desirable for applications like commercial and retail lighting, while maintaining the efficiency and longevity of LEDs.
Innovation Solution
The use of filters that selectively filter certain wavelengths of light from LED light sources, such as blue and green/yellow portions, to adjust the color temperature while maintaining a high CRI, allowing for the production of warm white light with a color temperature of 2500K or lower, achieving a CRI of 90 or higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LED light sources are used to achieve energy efficiency and longevity, then energy consumption is reduced and operational lifetime is extended, but the color temperature and CRI cannot simultaneously achieve desirable warm white light characteristics
Solution Approach 1:
A filter is introduced as an intermediary component between the LED light source and the environment. The filter selectively transmits certain wavelengths while blocking others, transforming the LED's native spectrum into a warm white light spectrum with high CRI. This mediator enables the LED to achieve desirable color temperature (2700K-4000K) and CRI (Ra≥90) without changing the LED's efficient energy conversion properties.
2Use of energy by moving object
If LED light sources are used to achieve energy efficiency, then energy consumption is reduced, but the ability to reproduce colors faithfully (CRI) is compromised
Solution Approach 1:
The filter acts as an intermediary that shapes the spectral output to match the ideal black-body radiator spectrum. By selectively transmitting wavelengths in the visible range and blocking harmful UV and excessive blue light, the filter ensures faithful color reproduction (CRI Ra≥90) while the LED maintains its energy efficiency advantages.
Solution Approach 2:
The filter modifies the spectral parameters of the LED output by adjusting the transmission characteristics across different wavelengths. This parameter transformation converts the LED's broad spectrum into a controlled spectrum that peaks in the yellow-green region, achieving both energy efficiency and high color rendering accuracy.
3Duration of action of stationary object
If LED light sources are used to achieve extended operational lifetime, then durability is improved, but the light output lacks the warm color temperature and high CRI characteristics
Solution Approach 1:
The filter serves as a mediator that transforms the LED's cool white light into warm white light with color temperature between 2700K-4000K. The filter's wavelength-selective transmission properties enable this color transformation while the LED continues to operate with its extended lifetime characteristics, as the filter does not affect the LED's operational durability.
4Illumination intensity
If filters are added to LED light sources to achieve warm white light with high CRI, then color rendering is improved, but device complexity increases
Solution Approach 1:
The filter is a simple intermediary component that can be implemented as a single optical element in the light path. This minimalistic approach achieves high CRI (Ra≥90) and desirable color temperature without requiring complex multi-component systems, maintaining ease of manufacture and installation.
5Temperature
If filters are used to adjust color temperature of LED light, then warm white light is achieved, but light output intensity is reduced
Solution Approach 1:
The filter is designed with optimized transmission characteristics that maximize the transmission of useful visible wavelengths while blocking harmful UV and excessive blue light. This parameter optimization ensures that the majority of the LED's energy output is preserved in the transmitted light, minimizing energy loss while achieving the desired warm white color temperature and high CRI.
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 enables the creation of warm white light with high CRI, enhancing the energy efficiency and longevity of LEDs, providing an inexpensive and easy method to achieve desirable lighting characteristics for various applications.
Implementation Method 1
A filter is arranged so that at least some light from the LED light source passes through it, with the filter filtering at least a portion of the light source emission spectrum
Data Source
AI summary
Solid state light sources, lighting devices and lamps arranged to provide emission with a warm temperature and high CRI. One embodiment of a solid state lighting device according to the present invention comprises a light emitting diode (LED) device capable of emitting light in an emission spectrum. A filter arranged so that at least some light from the LED light source passes through it, with the filter filtering at least some of one or more portions of the light source emission spectrum. The resulting light source light has a different temperature but substantially the same CRI after passing through the filter.