Patent Application
20220178515
The present application relates, generally, to modifying the color of light emitted from a lamp, and, more specifically, to a color correcting optical component (CCOC) for reducing the correlated color temperature (CCT) of light from a light source.
Conventionally, “color correction” of light from 3000K down to, approximately, 2700K, 2500K, or 2200K is performed by using a ¼, ½ or ¾ color temperature orange (CTO) filter, respectively. The challenge with this approach is that the only way a filter can shift a spectral power distribution (SPD) from a cooler to warmer temperature is to absorb light in the 400-575 nm range. Often this is accomplished with a filter that is fairly broad, thus detrimentally suppressing light in the yellow/green region, where the photopic curve is centered. More specifically, as can be seen from the plots in
What is needed is a color correcting optical component (CCOC) for reducing the correlated color temperature (CCT) without reducing lumens by absorbing in the yellow/green region. The present invention fulfills this need, among others.
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.
Applicant recognizes that using quantum dots (QDs) in an CCT converter will allow for true conversion of shorter wavelength light (e.g., violet or blue) into red, while leaving yellow and green light untouched. The approach has multiple advantages, including: (1) lumens are not wasted by absorbing in the yellow/green region; (2) red output can be tuned to optimize color fidelity; and (3) reducing violet/blue light pushes the color point of the emitted light to the right on the CIE diagram, and adding red light pulls the color point down on the CIE diagram, and thus (1) because red output is closer to the photopic curve than the blue/violet, the added lumen output in red helps lumen efficacy, and (2) because the shift is to the right and down, this will tend keep the color point closer to the black body curve or perhaps shift below it—which is preferential for warmer CCTs.
In one embodiment, the invention relates to a color correcting optical component (CCOC) for reducing the correlated color temperature (CCT) of a light source emitting a first light, the CCOC comprising: (a) a light transmitting component, the light transmitting component being discrete from the light source; (b) a connector operatively attached to the light transmitting component for connecting the light transmitting component to the light source such that at least a portion of the first light passes through the light transmitting component; (c) a plurality of quantum dots (QDs) disposed in the light transmitting component, the QDs configured to downconvert a portion of the first light to a second light, wherein the light transmitting component emits emitted light comprising a combination of at least the first light and second light.
In the following paragraphs, the present invention will be described in detail by way of example with reference to the attached drawings. Throughout this description, the preferred embodiment and examples shown should be considered as exemplars, rather than as limitations on the present invention. As used herein, the “present invention” refers to any one of the embodiments of the invention described herein, and any equivalents. Furthermore, reference to various feature(s) of the “present invention” throughout this document does not mean that all claimed embodiments or methods must include the referenced feature(s).
Referring to
The QDs are configured to downconvert a component of light having a relatively short wavelength to a longer wavelengths. In one embodiment, the QDs are non-cadmium containing QDs. Such QDs are known and commercially available (See, e.g., https://www.nanosysinc.com/products and https://crystalplex.com). In one embodiment, the first light comprises at least a blue or violet component and the QDs downconverts a portion of the blue or violet component to red light. In a more particular embodiment, the first light comprises a blue component and the QDs downconverts a portion of the blue component to red light.
The QDs of the OCCOC function to lower the CCT of the emitted light without substantially reducing luminous flux. In one embodiment, the first light has a CCT of at least 3000K and the emitted light has a reduced CCT of no greater than 2700K, or no greater than 2400K, or no greater than 2220K. In one embodiment, the reduction of CCT does not result in a significant reduction of luminous flux. For example, assuming that the first light has a first luminous flux, in one embodiment, the emitted light has an emitted luminous flux no less than 80% of the first luminous flux, or no less than 85% of the first luminous flux, or no less than 90% of the first luminous flux, or no less than 95% of the a first luminous flux. In one embodiment, the CCOC of the present invention minimizes the reduction of luminous flux by not using a filter.
An advantage of using QDs is their relatively low light scattering compared to other downconverters, such as, for example, phosphors. By way of background, often lamps are configured as spot lamps in which the emitted light has a narrow beam angle, for example, 10-15 degrees. Light scattering of a CCOC used to reduce the CCT will significantly impact beam angle. However, the low light scattering characteristics of QDs reduce the negative effect the CCOC may have on beam angle. More specifically, as addressed in https://www.nature.com/articles/s41598-017-16966-2 hereby incorporated by reference, QDs have about 30% collimating transmittance and 10% scattering with a blue pump. Therefore, for a blue pump beam, the ratio of light staying in the beam to scattering is around 3:1 If the beam is a red pump beam, then the ratio is about 3-4:1 In terms of lumens, this means about 75% of the lumens remain in the beam (in this example), and about 25% of the lumens are scattered outside the beam. Therefore, while there is some beam degradation, it is much less what would be encountered with phosphor, which has essentially no collimating transmittance, and thus would turn the collimated source into a Lambertian distribution on phosphor incidence. In one embodiment, the CCOC is configured such that the light emitted from the CCOC has a beam angle of less than 50 degrees, or less than 40 degrees, or less than 30 degrees, or less than 20 degrees.
The CCOC may be configured in different ways. For example, in one embodiment, the CCOC is configured as a disk as shown in
In one embodiment, as shown in
In one embodiment, the CCOC further comprises a total internal reflection (TIR) optics to configure the beam angle or shape. In one embodiment, the TIR optics are configured in a discrete component overlaid on the CCOC as disclosed in https://www.soraa.com/products/snap_system.php. For example, referring to
In one embodiment, the CCOC is discrete from the light source and is attached to the light source with a connector 403. In one embodiment, the connector connects the CCOC to the light emitting surface 410a of the light source 410. In one embodiment, the connector releasably connects the CCOC to the light emitting surface. In one embodiment, the connector is a magnetic connector. In one particular embodiment, the CCOC comprises a connection mechanism similar to that used in the commercially available Ecosense SNAP systems, see, for example, https://www.soraa.com/products/snap_system.php, hereby incorporated by reference. It should be obvious to those of skill in the art in light of this disclosure that the magnetic connector on the CCOC may comprise a magnet or a ferrous metal. Alternatively, rather than a magnetic connector, other know connection mechanisms may be used such as snaps, latches, threaded interconnections, friction interconnections, and adhesives.
Having thus described a few particular embodiments of the invention, various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements as are made obvious by this disclosure are intended to be part of this description though not expressly stated herein, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only, and not limiting. The invention is limited only as defined in the following claims and equivalents thereto.
This application claims the benefit of U.S. Provisional Application No. 63/120,989, filed Dec. 3, 2020, which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63120989 | Dec 2020 | US |
