LED Luminaire Warm Light via Red LED and Diffuser Mixing
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Solution Overview
Problem
LED light sources typically produce cool light, which is less desirable for illumination, despite being more efficient than other forms of lighting.
Innovation Solution
A luminaire design incorporating a plurality of cool white LEDs and at least one red LED, with a diffuser to mix the light and achieve a warmer correlated color temperature, maintaining high efficacy while providing a warm light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cool white LEDs are used for illumination, then energy efficiency and luminous efficacy are improved, but the color temperature becomes too cool (4000-10000K) which is less desirable for warm lighting applications
Solution Approach 1:
The patent combines cool white LEDs (providing high efficiency) with red LEDs (providing warm color) in a single luminaire system. The cool white LEDs maintain high luminous efficacy while the red LEDs contribute warm wavelengths, and their combined output creates a balanced warm white light with correlated color temperature of 2500-3900K through the diffuser medium.
Solution Approach 2:
The diffuser acts as an intermediary medium between the LED light sources and the observer. It receives light from both cool white and red LEDs, mixes the wavelengths, and outputs a uniform warm white light, thereby transforming the color characteristics while preserving energy efficiency.
2Temperature
If red LEDs are added to achieve warmer color temperature, then color preference is improved, but the overall luminous efficacy decreases due to lower efficiency of red LEDs compared to cool white LEDs
Solution Approach 1:
The patent uses local quality by deploying red LEDs sparsely (at least one red LED among multiple cool white LEDs) rather than uniformly distributing all LED types. This localized approach allows the majority of high-efficiency cool white LEDs to dominate the luminous output, while the red LEDs provide just enough warm color contribution to shift the correlated color temperature to 2500-3900K without significantly compromising overall efficacy.
3Temperature
If multiple red LEDs are used to enhance warm color output, then warmth perception is improved, but the complexity of the LED array increases
Solution Approach 1:
The patent applies partial action by using at least one red LED among multiple cool white LEDs, rather than requiring equal numbers or a complex mixture of LED types. This minimal red LED presence is sufficient to warm the overall light output to the desired 2500-3900K range while keeping the LED array configuration simple and the manufacturing process straightforward.
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
The solution effectively produces a warm light with a correlated color temperature between 2,500 to 3,900 Kelvin, enhancing user preference while maintaining the efficiency of cool white LEDs, reducing energy consumption, and extending lamp life.
Implementation Method 1
heat sink positioned adjacent and in thermal communication with the LED array
Implementation Method 2
diffuser for mixing the cool white LED light and the at least one red LED light
Data Source
AI summary
A LED luminaire comprises a heat sink disposed above an LED array and in thermal communication with the LED array, the LED array having at least one red LED and a plurality of cool white LEDs, the at least one red LED providing a warmer correlated color temperature for an output light and the plurality of white LEDs providing a higher efficacy, a diffuser positioned to enclose the LED array between the heat sink and the diffuser, the diffuser color mixing the at least one red LED and the plurality of cool white LEDs rendering a red light from the at least one red LED indiscernible from a cool white light of the plurality of white LEDs, a reflector positioned adjacent the heat sink.