RGBW LED Light Color Generation with Constant CRI
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Solution Overview
Problem
Existing methods for generating light with a desired color using RGB or RGBW algorithms result in a color rendering index (CRI) that is not constant across the color temperature spectrum, with maximum CRI values rarely exceeding 90%, and experiencing a significant drop in CRI values between 3800 and 5000 K.
Innovation Solution
A method combining the RGB and RGBW algorithms by determining first and second weighting values for red, green, blue, and white LEDs, and calculating overall weighting factors using a factor K, which adjusts the first weighting values to achieve constant CRI values above 90% across a wide range of color temperatures, utilizing the CIE standard color space diagram, particularly the CIELUV system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the RGB algorithm is used to determine weighting values for red, green and blue LEDs, then the method for adjusting light color is simple, but the color rendering index (CRI) value does not exceed 90% and is not constant across the color temperature spectrum
Solution Approach 1:
The patent combines the RGB algorithm and RGBW algorithm into a hybrid approach. It uses weighting values from both algorithms (W1_r, W1_g, W1_b from RGB algorithm and W2_r, W2_g, W2_b, W2_w from RGBW algorithm) and merges them through a calculation involving factor K to achieve CRI values above 90% while maintaining methodological simplicity
Solution Approach 2:
The patent creates a composite weighting strategy by integrating results from two different algorithms. The overall weighting factors WG_r, WG_g, WG_b, WG_w are formed as composite values combining contributions from both RGB and RGBW algorithm outputs, achieving superior color rendering performance
2Manufacturing precision
If the RGBW algorithm is used to determine weighting values for red, green, blue and white LEDs, then the color rendering index (CRI) value exceeds 90% over wide ranges of color temperature, but the CRI value falls off to a minimum significantly below 90% in the color temperature interval between 3800 and 5000 K
Solution Approach 1:
The patent introduces a feedback mechanism by calculating factor K based on the second weighting value W2_r from the RGBW algorithm and a reference value A (0.3-0.5). This factor K is then fed back into the weighting calculation to adjust the overall weighting factors, creating a self-correcting system that maintains stable CRI values across different color temperatures including the problematic 3800-5000 K range
Solution Approach 2:
The patent changes the parameter approach by introducing a new calculation parameter K that modifies the weighting values dynamically. This parameter K = A - W2_r (where A is between 0.3 and 0.5) adjusts the contribution of different LED components based on their specific characteristics, ensuring consistent high CRI values across the entire color temperature spectrum
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 method generates light with a CRI value of up to 96%, providing high-quality color rendering that is consistent across various color temperatures, similar to sunlight, and is perceived as more agreeable by humans.
Implementation Method 1
using at least one light-emitting diode emitting red, at least one light-emitting diode emitting green, at least one light-emitting diode emitting blue and at least one light-emitting diode emitting white
Data Source
AI summary
The invention relates to a method for generating light with a desired light color by using at least one light-emitting diode emitting red r-LED, at least one light-emitting diode emitting green g-LED, at least one light-emitting diode emitting blue b-LED and at least one light-emitting diode emitting white w-LED. In order to improve the CRI value, according to the invention it is proposed that weighting values ascertained according to the RGB algorithm and further weighting values ascertained according to the RGBW algorithm be combined together by using a correction factor.