The present subject matter relates to light emitting diodes (LEDs) used for lighting, and specifically to the spectral power distributions (SPDs) of the individual LEDs and arrays comprising those LEDs.
Performance of a light array depends, at least in part, on what emitters are utilized in the light array. The range of colors a light array can produce generally improves as more differently colored emitters and control channels are added. However, simply adding more differently colored emitters adds to the cost and complexity of the light array. Performance generally improves as more emitters and control channels are added, but the cost and complexity of the light array increases. Presented herein are custom LEDs with unique optical properties that combine to create light arrays with high performance and while maintaining low complexity (i.e., a low number of LED channels).
The disclosure provides a light fixture including a substrate and a plurality of light emitting diodes mounted on the substrate. The plurality of light emitting diodes includes a first light emitting diode having a peak wavelength within a range of 600 nanometers and 630 nanometers, and a full width at half maximum value of at least 140 nanometers.
The disclosure also provides a light emitting diode including a peak wavelength within a range of 600 nanometers and 630 nanometers, a full width at half maximum value of at least 140 nanometers, and a CIE 1931 (x,y) chromaticity coordinate with an x-value within a range of 0.430 and 0.550 and a y-value within a range of 0.423 and 0.477.
The disclosure also provides a light emitting diode including a peak wavelength within a range of 450 nanometers and 470 nanometers, a full width at half maximum value within a range of 40 nanometers and 60 nanometers, a dominant wavelength within a range of 450 nanometers and 472 nanometers; and an excitation purity within a range of 95% and 100%.
The disclosure also provides a light emitting diode including a peak wavelength within a range of 510 nanometers and 520 nanometers, a full width at half maximum value within a range of 30 nanometers and 40 nanometers, a dominant wavelength within a range of 510 nanometers and 520 nanometers; and an excitation purity within a range of 75% and 90%.
The disclosure also provides a light emitting diode including a peak wavelength within a range of 650 nanometers and 670 nanometers, a full width at half maximum value within a range of 30 nanometers and 55 nanometers, a dominant wavelength within a range of 640 nanometers and 655 nanometers, and an excitation purity within a range of 96% and 100%.
The disclosure also provides a light fixture including a substrate and a plurality of light emitting diodes mounted on the substrate. The plurality of light emitting diodes include a first channel with a first light emitting diode and a second light emitting diode. The second light emitting diode has a different peak wavelength than the first light emitting diode. The plurality of light emitting diodes also includes a second channel with a third light emitting diode and a fourth light emitting diode. The fourth light emitting diode has a different peak wavelength than the third light emitting diode.
Before any embodiments are explained in detail, it is to be understood that the subject matter described herein is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The subject matter described herein is capable of other embodiments and of being practiced or of being carried out in various ways.
In addition, it should be understood that embodiments may include hardware, software, and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic-based aspects may be implemented in software (e.g., stored on non-transitory computer-readable medium) executable by one or more processing units, such as a microprocessor and/or application specific integrated circuits (“ASICs”). As such, it should be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components, may be utilized to implement the embodiments. For example, “servers” and “computing devices” described in the specification can include one or more processing units, one or more computer-readable medium modules, one or more input/output interfaces, and various connections (e.g., a system bus) connecting the components.
Relative terminology, such as, for example, “about,” “approximately,” “substantially,” etc., used in connection with a quantity or condition would be understood by those of ordinary skill to be inclusive of the stated value and has the meaning dictated by the context (e.g., the term includes at least the degree of error associated with the measurement accuracy, tolerances [e.g., manufacturing, assembly, use, etc.] associated with the particular value, etc.). Such terminology should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4” also discloses the range “from 2 to 4”. The relative terminology may refer to plus or minus a percentage (e.g., 1%, 5%, 10%, or more) of an indicated value.
Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings.
With reference to
With reference to
With continued reference to
The light source 22 further includes collimating optics in the form of twelve collimator packs 52 ultrasonically welded to the primary optic holder 40. Each collimator pack 52 includes a back plate 54 and five collimator lenses 56 protruding from the back plate 54 toward the primary optic holder 40. Each collimator lens 56 is positioned in a corresponding through hole 42 of the primary optic holder 40 and includes a parabolic surface that functions to reflect light from the corresponding LED 34 into the mixing assembly 24 by total internal reflection. The surface of the collimator lens 56 is slightly spaced from the tapered surface 44 of the primary optic holder 40. Each collimator lens 56 includes a cylindrical recess 60 that receives the corresponding LED 34. Alternatively, the collimator packs 52 could be formed as a single piece molded glass optic.
As explained in greater detail below, the LED light fixture 10 is configured to produce a color mix that unexpectedly produces a light mix with improved performance using a lower number of emitter types and channels.
As used herein, the following colors of LEDs are deemed to produce the dominant wavelengths listed in Table 1 below.
Unless otherwise indicated, a conventional LED is categorized by the range in which the dominant wavelength falls into and may be selected from, for example, a Luxeon LED in the C Color Line, Rebel Color Line, or Z Color Line (e.g., P/N L1C1-RED1000000000 (629 λP, FWHM=20 nm) and P/N L1C1-LME1000000000 (556 λP, FWHM=80 nm)). As used herein, the standard metric, excitation purity, is calculated using the standard illuminant D65, with x=0.3127, y=0.3291, as the reference point.
With reference to
With continued reference to
The user interface 125 is included to control the control system 100. The user interface 125 is operably coupled to the controller 105 to control, for example, the output of the light arrays 110A-110C, and generate and provide control signals for the driver circuits 115A-115C. The user interface 125 can include any combination of digital and analog input devices to achieve a desired level of control for the control system 100. For example, the user interface 125 can include a computer having a display and input devices, a touch-screen display, a plurality of knobs, dials, switches, buttons, faders, or the like. In some embodiment, the user interface 125 is separated from the control system 100 (e.g., as a portable device communicatively connected to the controller 105).
The driver circuits 115A-115C include a first driver circuit 115A, a second driver circuit 115B, and a third driver circuit 115C that are operable to provide control signals to the light arrays 110A-110C. For example, the first driver circuit 115A is connected to a first light array 110A for providing a drive signal (i.e., an excitation current) to the first light array 110A (i.e., a first LED control channel). The second driver circuit 115B is connected to a second light array 110B for providing a drive signal to the second light array 110B (i.e., a second LED control channel). The third driver circuit 115C is connected to a third light array 110C for providing a drive signal to the third light array 110C (i.e., a third LED control channel). In the illustrated embodiment, there are three LED control channels shown. In other embodiments, less than three LED channels may be used in a light fixture. In other embodiments, more than three LED channels may be used in a light fixture. As described, a LED channel has one or more LEDs that are connected such that they operate together (i.e., they are on the same electrical output and receive the same excitation current from the driver).
The power control circuit 120 supplies a nominal AC or DC voltage to the control system 100. In some embodiments, the power control circuit 120 is powered by one or more batteries or battery packs. In other embodiments, the power control circuit 120 is powered by mains power having nominal line voltages between, for example, 100 V and 240 V AC and frequencies of approximately 50-60 Hz. The power control circuit 120 is also configured to supply lower voltages to operate circuits and components within the control system 100.
The controller 105 is connected to light arrays 110A-110C. In some embodiments, the light arrays 110A-110C are arranged as the LEDs 34 are shown in
Various custom LEDs are described herein for use alone or in combination with other LEDs in a light fixture.
With reference to
With reference to
The custom blue LED and the custom blue and indigo hybrid LED have advantages over conventional blue LEDS. A major source of color mixing error in conventional light fixtures is the chromaticity shift in different bins of blue LEDs. The custom blue LED and the custom blue and indigo hybrid LED improves rendering, especially for high-CCT whites. In addition, the custom blue LED and the custom blue and indigo hybrid LED can approximate the CIE
With reference to
The custom green LED has advantages over conventional green LEDs. The custom green LED can combine with a conventional lime LED in a light fixture to create a less-saturated green. In addition, the custom green LED may combine with the custom blue or custom blue and indigo hybrid LED to create certain desirable blue filter colors (e.g., a well-known blue gel filter color). Also, the custom green LED improves the performance of a light fixture in the ability to reach P1 design status under Annex E of TM-30-18, as explained in further detail below.
With reference to
In some embodiments, the custom yellow includes a CIE 1931 (x,y) chromaticity coordinate with an x-value within a range of approximately 0.4300 and approximately 0.5500 and a y-value within a range of approximately 0.4230 and approximately 0.477. In some embodiments, the custom yellow includes a CIE 1931 (x,y) chromaticity coordinate within an area defined by consecutively connected vertices: (0.5500, 0.4230), (0.5050, 0.4770), (0.4300, 0.4400), (0.4500, 0.4250), and (0.5000, 0.4400). In other words, the vertices are connected consecutively by straight lines to define a polygon with an area in the CIE 1931 color space, and the custom yellow includes a chromaticity coordinate within that area. The interior of this area is to the left as these vertices are traversed counterclockwise as viewed in the CIE 1931 color space. In other words, the custom yellow, in some embodiments, may have any CIE 1931 (x,y) chromaticity coordinate within the area defined by the vertices. In another embodiment, the CIE 1931 (x,y) chromaticity coordinate area for the custom yellow is bounded by a different range. For example, the CIE 1931 (x,y) chromaticity coordinate for the custom yellow may be within an area (i.e., a rectangle) defined by vertices: (0.5035, 0.4522), (0.5191, 0.4366), (0.5305, 0.4480), and (0.5149, 0.4636).
The custom yellow LED has advantages over conventional yellow LEDs and conventional amber LEDs. In particular, the custom yellow LED provides red content that is lacking in conventional amber LEDs. The spectral power distribution 220 of the custom yellow LED can further desaturate with some blue to fill spectral gaps between, for example, the custom blue LED and the custom green LED, which would make the emitter pastel/white.
Specifically, the spectral power distribution 220 of the custom yellow LED resembles a spectral power distribution 230 of a conventional white LED but without a prominent blue “pump.” In order to be binned as a white, manufactures balance the pump (approximately 450 nm) emission with the broadly down-converted phosphor mission (>500 nm) to cause the chromaticity to fall on or very near to the Planckian locus. In contrast, the custom yellow LED pump is suppressed; causing its chromaticity to lie well away from the Planckian locus. When the custom yellow LED is employed in color-mixed arrays, such as those described herein, the custom yellow LED allows a user to choose to create a high-quality white light. The comparison of the fractional energy of various blueward pumps for conventional white LEDs at different temperatures and the custom yellow LED in Table 5.
With reference to
With reference to
The custom red LED has advantages over conventional red LEDs. For example, the custom red LED according to the first embodiment approximates the chromaticity of far red (740 nm) while not sacrificing brightness, thereby deepening the gamut. The custom red LED accomplishes this by removing the amberward portion of the deep red spectrum (“deep red” is approximately λD=640 nm, λP=661 nm, FWHM=21 nm). Also, the custom red LED according to the second embodiment combines the functionality of red and deep red by adding a broad range of long wavelengths that are typically missing from conventional LED light sources. As such, the custom red LED is able to restore rendition nuances that were possible with halogen, incandescent, and daylight sources. The custom red LED accomplishes this while still utilizing a single control channel and without mixing chip types on a single string. The custom red LED according to the third embodiment represents a combination of the custom red LED according to the first and second embodiments.
The above described custom LEDs have unique characteristics as stand-alone LEDS, but also create unique characteristics and properties when combined into a custom LED light array. Custom light arrays with varying numbers of LED control channels are described herein. Any one of the custom light arrays described herein may be integrated with the light fixture 20, the LEDs 34 and/or the light arrays 110A-110C.
With reference to
With reference to
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Correlated Color Temperature (CCT) defines the color appearance of a white LED. CCT is defined using the Kelvin scale with a “warm” white light around 2700 K and “cool” white light around 5000 K.
Rf is a fidelity index, which indicates how similar the rendering is to a reference illuminant. The max value for Rf is 100. Rf is determined using a well-defined process such as is described in IES TM-30-18 published by the Illuminating Engineering Society (IES), and evaluates the fidelity of a light source when compared to a reference.
Rg is the gamut index, which essentially indicates an average chroma shift, or saturation change, relative to the reference. Rg is determined using a well-defined process such as is described in IES TM-30-18. A Rg value of less than 100 is undersaturated or muted, whereas a Rg value of greater than 100 is oversaturated or vivid. Also, Rg takes hue shift into account.
Rcs,h1 indicates a chroma-shift (saturation change) measure for color samples in hue bin 1, which includes objects with red appearance. Rcs,h1 can be a useful contributing indicator when skin rendition is important. For example, if Rcs,h1 is too low, in conjunction with Rf and/or Rg it may indicate the illuminant may make skin appear sallow or pale. In contrast, if the Rcs,h1 is too high, in conjunction with Rf and/or Rg it may indicate the illuminant may make skin appear flushed or overly red. Primarily, hue bin 1 is key because experimental data has shown red rendition to be an important indicator for humans. Research suggests typical observers aesthetically prefer a slight boost in reds and notice when red is missing.
Rf,h1 indicates fidelity for color samples in hue bin 1.
The Annex E provides design guidance on what purposes the illuminant is likely to be suited for. Annex E is an annex to the ANSI/IES TM-30-18 standard. Annex E includes three design intent categories: preference (P), vividness (V), and fidelity (F), and scoring within those categories range from priority level 1 (highest) to priority level 3 (lowest). High levels of priority increase the likelihood of achieving the given design intent, whereas lower levels offer increased flexibility to account for other considerations.
The 4 measures listed (Rf, Rg, Rcs,h1, Rf,h1) are used in Annex E to calculate suitability for a given design intent category. Specifically, hue bin 1 is crucial in the Annex E design criteria. Rcs,h1 values are required to determine all three priority levels for both preference and vividness. Rf,h1 values are required to determine fidelity priorities F2 and F3. In applications where skin rendition is important, preference and/or fidelity are likely to be high priorities.
The Color Rendering Index Ra (CRI) provides a representation of an artificial light's accuracy of rendering a sample set of colored objects in comparison to a reference source. A perfect CRI score is 100, which indicates that the artificial light source renders the color sample set the same as the reference source.
R9 is a supplemental score to the CRI value that judges a light sources' color rendering ability, specifically as it concerns red-hued objects.
The Television Light Consistency Index (TLCI) is used in order to predict a light's ability to accurately render color when captured by a television camera and viewed on a display and was created by the European Broadcasting Union (EBU). The TLCI is based on a mathematical calculation implemented in software called TLCI-2012, which is specified in EBU Tech 3355. Like the CRI value, the TLCI value has a maximum of 100. In general, when recording on a camera in a studio setting, a higher TLCI is considered desirable.
The candle color array has advantages as a custom two channel LED light array. The custom yellow LED paired with the blue LED (or the custom blue LED or the custom blue and indigo hybrid LED) creates a low-CCT (approximately 2400 K), high-rendering (CRI approximately equal to or greater than 90) white. Conventional low-CCT whites typically have lower rendering quality. The candle color array permits in-house calibration by balancing the flux from the two emitters to ensure a chromaticity on the Planckian locus 316.
With reference to
With reference to
With reference to
The fade-to-warm array has advantages as a custom three channel LED light array. The custom yellow LED and the custom red LED combine with a conventional white LED (e.g., a 3000 K white) to achieve high quality rendering as the color temperature is lowered and reaches Annex E design priority level 1 for preference (P1). For example, the fade-to-warm array creates a color mix with a CCT of 2400 K and an Annex E priority level 1 for preference (P1).
With reference to
With reference to
With reference to
The four-channel array has advantages as a custom four channel light array. Conventional simple color-tunable arrays typically include emitters that are red, green and blue (RGB) and white (RGBW) or amber (RGBA) (“conventional short arrays”). Rendering performance is often poor with these conventional short arrays. Although, the addition of a white LED and an amber LED to create a RGBAW array improves rendering performance, it would have a total five control channels and drivers (one for each of red, blue, green, amber, and white) and would require use of sophisticated color-mixing algorithms. The custom yellow LED in the four-channel array offers the gamut benefits of an RGBA array and the rendering benefits of including an explicit white emitter in a simple four channel package. For example, the four-channel array emits a color mix with a CCT within a range of approximately 3200K to approximately 5600K while maintaining an Annex E priority level 1 for preference (P1). Of note, with reference to
Additional comparisons of the four-channel array to conventional RGB and RGBAW arrays are illustrated in Table 10. The four-channel array has rendering benefits in white as well as in saturated colors. For example, the four-channel array is able create rich and highly nuanced revelation of color in objects or environments, whether for entertainment applications such as theatrical backdrops or scenery or for creating certain effects, moods, or revealing depth and variety in materials, such as in marble or granite, in architectural applications.
With reference to
With reference to
With reference to
The five-channel array has advantages as a custom five channel light array. In particular, the five-channel array achieves priority level 1 for both preference (P1) and fidelity (F1) under Annex E for a range of temperatures (e.g., 3200 K to 5600 K).
With reference to
With reference to
With reference to
The hybrid four-channel array has advantages as a custom four channel light array. By combining the custom yellow LED with a conventional lime LED in a hybrid channel, the hybrid four-channel can be used to create white light of high quality, while maintaining a familiar and desirable gamut. The quality of the hybrid four-channel array is further improved by using a hybrid channel of red and deep red. Hardwiring more than one colored LED together on a single channel to achieve a mixed color that is not otherwise available as a single LED is advantageous because it reduces the number of drivers required to control the light fixture.
With reference to
As demonstrated by the example arrays described herein, a light fixture with a processor for driving the plurality of light emitting diodes to create a color mix, wherein at least one of the LEDs is the custom yellow LED has advantages. For example, the color mix can have a TM-30-18 Annex E priority level 1 for preference (P1) for a CCT range of approximately 3200 K to approximately 5000 K. Likewise, the color mix can have a CRI value of at least 90 for a CCT range of approximately 2400 K to approximately 5000 K. In addition, the color mix can have a TM-30-18 Rf value of at least 95 for a CCT range of approximately 2400 K to approximately 5000 K.
Although the subject matter described herein has been described in detail with reference to certain embodiments, variations and modifications are possible in view of the above disclosure or may be acquired in association with making and/or using one or more of the disclosed embodiments.
This application claims the benefit of U.S. Provisional Patent Application No. 62/946,846, filed Dec. 11, 2019, the entire content of which is hereby incorporated by reference.
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20210185779 A1 | Jun 2021 | US |
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62946846 | Dec 2019 | US |