Systems and methods for controlling the spectral content of LED lighting devices

Abstract

Systems and methods for improving color accuracy and uniformity in LED illumination systems are disclosed including light engines, switching circuits and methods of adding phosphors or lumiphoric materials for controlling the addition or subtraction of light from one or more color light sources of the light engines to produce light of a uniform and consistent color. Systems and methods of providing LED light engines and associated illumination spectrums that are both visually appealing, rich in melanopic flux and that reduce blue light hazard exposure are also disclosed.

Description

RELATED APPLICATIONS[0001]This application is a continuation application of application Ser. No. 15 / 364,533, filed Nov. 30, 2016, which is a continuation-in-part application of U.S. patent application Ser. No. 15 / 264,197, filed Sep. 13, 2016, now U.S. Pat. No. 9,788,387, both of which claim priority to and the benefit of U.S. Provisional Application No. 62 / 323,021, filed Apr. 15, 2016, U.S. Provisional Application No. 62 / 380,842, filed Aug. 29, 2016, and U.S. Provisional Application No. 62 / 218,946, filed Sep. 15, 2015. The contents of each of the aforementioned patent applications are incorporated herein in their entireties.[0002]Except to the extent that any of the disclosure in the referenced patents conflicts with the disclosure herein, the following US patents, which include inter alia disclosure pertaining to light emitting diodes, LED luminaires and light engines, color mixing, power delivery, LED driving and switching methods and systems, and phosphors and other lumiphoric ma...

AI Technical Summary

Benefits of technology

The present invention provides a light engine that can produce consistent and melanopic-rich light output through a switching circuit. The light engine can adjust the chromaticity coordinates through a calibration process and provide a visually appealing and uniform illumination spectrum with melanopic-rich flash. The invention also includes a lighting device that is not depleted in the melanopic region while maintaining consistent color temperature, and is suitable for protecting against blue light hazard, retinal oxidative stress, and facilitating the entrainment of circadian rhythms of mammals.

Problems solved by technology

At present, LED manufacturers are challenged to produce uniform color points in their white LEDs and are limited to a “bandwidth spread” in their monochromatic LEDs as well.

In many circumstances, until the packages are assembled into an operational luminaire or lighting device, the extent of any such variability cannot be fully determined.

A lighting designer or manufacture attempting to construct a luminaire with a specific color output spectrum is challenged to provide a luminaire with consistent color output while using LEDs which may have an unacceptable wide range (e.g., 5 nm) of light output.

Hence, because of the enhanced visual discrimination in the 480-500 nm color region, employing monochromatic LEDs in this region may result in unacceptable perceived color differences between LED fixtures that are designed to yield the same color output.

Generating an LED spectrum with a consistent (x, y) color point while using monochromatic enhancement in the region from 480 nm-500 nm is a problematic challenge.

Conventional LED lighting fixtures provide less than optimal and potentially insufficient light in these biologically important wavelength ranges (e.g., non-visual stimulus) at standard light levels.

Even with conventional light levels, blue light exposure may cause long term damage over the course of years of exposure.

Insufficient stimulus of the RGCs, which may occur in the absence of sufficient melanopic light, that is light that falls within the melanopsin action spectrum region as shown in FIG. 3 and which provides the necessary stimulus of the RGCs, may result in reduced pupillary constriction, thereby allowing more blue light to enter the eye potentially resulting in increased and accelerated oxidative stress on the retina.

Thus, the range of optical frequencies used to excited broadband emission phosphors in conventional LED technology directly overlap the blue region known as blue light hazard.

However, these 6500K spectrum LEDs are typically depleted of spectral energy in the 490 nm region and produce a large or heightened amount of 450 nm light.

This conventional situation may pose health hazards including potential retinal damage because the conventional white light producing LEDs, which do not have continuity between the melanopic region and the blue light hazard region, may result in inappropriate pupillary dilation during exposure to potentially harmful blue light blue light.

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