Narrowband photosynthetically active radiation ("PAR") substantially only at each of multiple emission wavelengths yields good photosynthesis at reduced engery cost

Abstract

Produced PAR neither replicates the spectral bandwidth of sunlight at the surface of the earth, nor the absorption spectrum of green plants, nor the absorption spectrum of photosynthetic processes, but—based on discovery that PAR at only a number of unique wavelengths is optimally energy-efficient to promote normal or better plant growth—instead desirably concentrates PAR emissions in a limited number, preferably about nine (9), narrow bands. Narrowband, even extremely narrowband, radiation is preferred at 430 and 662 nanometers wavelength (first and second absorption peaks of chlorophyll A); 453 and 642 nanometers wavelength (first and second absorption peaks of chlorophyll B); and still other wavelengths (only). Preferably more than 50% of the total PAR flux is within a total bandwidth of less than 160 nanometers wavelength in the range between 360 and 760 nanometers wavelength, and more preferably 90% of the PAR flux is within a total bandwidth of less than 80 nanometers wavelength within this range. When the intensity of the PAR flux in these narrow bands is, as is preferred, only but that occurring within the normal solar spectrum, then tremendous energy savings are innately realized in production of the new-spectrum PAR, ranging to ¾ and more from previous PAR. Moreover, the new-spectrum multi-narrow-band PAR is electrically efficiently produced using narrowband-emission LEDs.

Claims

1-2. (canceled)

3. A lighting system for producing photosynthetically active radiation (“PAR”) comprising: a multiplicity of narrowband light sources, more than 4 but 15 or less in number, producing a corresponding multiplicity of narrowband light emissions at a corresponding multiplicity of emission wavelengths within the range from 360 to 760 nanometers wherein more than 50% of the light flux produced at each of said multiplicity of emission wavelengths is within a bandwidth of 10 nanometers or less containing a corresponding local emission peak, and is thus called narrowband emission; [whereby] wherein since the maximum number of light sources is 15 and the actual number can be as low as 4, and since each of these light sources does produce more than 50% of its light flux within a maximum bandwidth of 10 nanometers wavelength or less, then more than 50% of the total light flux is produced within a maximum total bandwidth of only 150 nanometers wavelength or less, making that, at most, the remaining 250 nanometers, or more, bandwidth between 360 and 760 nanometers contains less than 50% the total light flux produced by the multiplicity of narrowband light sources; [whereby] wherein more than 50% of the light flux is within a total bandwidth of 150 nanometers wavelength or less while less than 50% of the light flux is within a total bandwidth of 250 nanometers wavelength or more.

4-11. (canceled)

12. An energy-conserving method of applying photosynthetically active radiation (“PAR”) effective for photosynthesis to plants, the method comprising: applying PAR to plants in a multiplicity of narrowband emissions, the narrow bands being more than 4 but 15 or less in number, within the range from 360 to 760 nanometers wavelength; wherein more than 50% of the PAR flux at each of said multiplicity of narrowband emission is within a bandwidth of 10 nanometers wavelength or less containing a corresponding local emission peak, and is thus called a narrowband emission; wherein since the maximum number of narrow bands is 15, and since each of these narrow bands does have more than 50% of its PAR flux within a maximum bandwidth of 10 nanometers wavelength, then more than 50% of the total PAR flux is applied within a maximum total bandwidth of only 150 nanometers wavelength or less, making that, at most, the remaining 250 nanometers bandwidth between 360 and 760 nanometers receives less than 50% the total PAR flux from the multiplicity of narrowband light sources; wherein the applying results in less than 50% of the total applied PAR flux falling within a bandwidth of at least 250 nanometers wavelength, and thus uses less energy than any hypothetical method that would apply PAR flux in this at bandwidth of at least 250 nanometers which PAR flux was at least equal to that applied in the maximum total bandwidth of 150 nanometers.

13. The method according to claim [10] 12 wherein the applying of PAR comprises: first-applying PAR in a narrow band including a wavelength of 430 nanometers that is a first absorption peak of chlorophyll A; second-applying PAR in a narrow band including a wavelength of 662 nanometers that is a second absorption peak of chlorophyll A; third-applying PAR in a narrow band including a wavelength of 453 nanometers that is a first absorption peak of chlorophyll B; and fourth-applying PAR in a narrow band including a wavelength of 642 nanometers that is a second absorption peak of chlorophyll B.

14. The method according to claim [11] 13 wherein the applying of PAR comprises: fifth-applying PAR in a narrow band including a wavelength of 450 nanometers that is a first absorption peak of beta carotene; six-applying PAR in a narrow band including a wavelength of 480 nanometers that is a second absorption peak of beta carotene

15. The method according to claim [12 ] 14 wherein the applying of PAR comprises: seventh-applying PAR in a narrow band including a wavelength of 620 nanometers that is an absorption peak of phycocyanin.

16. The method according to claim [13 ] 15 wherein the applying of PAR comprises: eighth-applying PAR in a narrow band including a wavelength of 670 nanometers that is a first wavelength involved in the Emerson effect; ninth-applying PAR in a narrow band including a wavelength of 700 nanometers that is a second wavelength involved in the Emerson effect.

17. The method according to claim [10] 12 wherein each of (1) the first-applying, and (2) a majority of the third-applying through the ninth-applying, is of PAR that is within 50% of a same energy.

18. The method according to claim [10] 12 wherein the second-applying is of PAR that is within 50% of twice, ×2, the radiative energy that is within each of the first-applying, and a majority of the third-applying through the ninth-applying.

19. A source of photosynthetically active radiation (“PAR”) comprising: at multiplicity of at least 8 narrowband artificial light sources in the spectral range from 360 nanometers to 760 nanometers wavelength where each light source is called “narrowband” because it emits more than 50% of its radiation flux within a bandwidth no wider than 10 nanometers; wherein less than 50% of the radiation flux from at least eight of the multiplicity of light sources, collectively, is within a spectral region that is, in total, no greater than 80 nanometers wavelength bandwidth; wherein outside of the 10-nanometer maximum-widths of each of eight of the multiplicity of narrowband light sources, or within a total spectral region that is not less than 760−(8×10)=760-80=660 nanometers wavelength, there exists less than 50% of the radiation flux from the 8 light sources.

20. The source of PAR according to claim 19 wherein, although the multiplicity of light sources may number more than 8, more than 50% of the radiation flux from all the multiplicity of narrowband artificial light sources howsoever many there are, and any other artificial light sources, collectively, is within a spectral region that is, in total, less than 160 nanometers wavelength; wherein, conversely, outside of this spectral region of 160 nanometers wavelength, or within the remaining spectral region of 760−160=600 nanometers wavelength, there exists less than 50% of the radiation flux from all artificial light sources combined; wherein greater than 50% of the total artificial radiation flux from all sources is within a total bandwidth of 160/400, or less than 40% of the total spectral bandwidth between 360 nanometers and 760 nanometers wavelength, while less than 50% of the total artificial radiation flux from all sources is within a remaining bandwidth of 240/400 nanometers wavelength, or more than 50% (one-half)) of the total spectral bandwidth between 360 nanometers and 760 nanometers wavelength.

21. An energy-conserving method of applying photosynthetically active radiation (“PAR”) effective for photosynthesis to plants, the method comprising: applying PAR to plants in a multiplicity of narrowband emissions between 360 and 760 nanometers wavelengths so that more than 80% of the total PAR flux is applied within a maximum total bandwidth of only 150 nanometers wavelength or less, making that, at most, the remaining 250 nanometers bandwidth between 360 and 760 nanometers receives less than 20% the total PAR flux from said multiplicity of narrowband light sources; wherein the applying results in less than 20% of the total applied PAR flux falling within a bandwidth of at least 250 nanometers wavelength, and thus uses less energy than any hypothetical method that would apply PAR flux of more than 20% in this bandwidth of at least 250 nanometers; and wherein a minimum of 80% of PAR flux falls within150/400=⅜ths of PAR bandwidth between 360 and 760 nanometers leaving that a maximum of 20% of PAR flux should fall within a 250/400=⅝ths of the same 360 nm to 760 nm PAR bandwidth.

22. The method of claim 21 wherein that minimum 80% of the overall total PAR flux that is applied to the 150 nm bandwidth is so applied as a multiplicity of at least 8 narrowband artificial light sources each in the spectral range from 360 nanometers to 760 nanometers wavelength where each light source is called “narrowband” because it emits more than 80% of its radiation flux within a bandwidth no wider than 10 nanometers; wherein not only Is a minimum 80% of the total PAR flux applied within a bandwidth totaling 150 nm or less, but even within this bandwidth more than 50% of the applied PAR is within a maximum of 8×10 nm, or 80 total nm, or but 80/400 or 20% of the bandwidth between 360 nm and 760 nm.

23. A method of applying photosynthetically active radiation (“PAR”) effective for photosynthesis to plants, the method comprising: applying PAR to plants in a multiplicity of four or more narrowband emissions between 360 and 760 nanometers wavelengths wherein these narrowband emissions both (1) total in combination more than 80% of the total PAR flux applied, with (2) this 80%+ narrowband flux applied itself totaling a maximum total bandwidth of only 150 nanometers wavelength or less; wherein this makes that the remaining 250 nanometers bandwidth between 360 and 760 nanometers must receive less than 20% the total PAR flux applied.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] FIG. 1, consisting of FIGS. 1a and 1b, are prior art graphs respectively showing the typical spectrum of light absorption by photosynthetic processes transpiring in an exemplary green plant, and a typical spectrum of PAR that has been applied (with various modifications) in the prior art as a growth light for plants.

[0075] FIG. 2a is a graph showing one, nominal, preferred spectrum of PAR—well capable of being produced in the real world (using LEDs), and applied as growth light for plants—in accordance with the present invention.

[0076] FIG. 2b is a graph showing another, aggressive, spectrum of PAR—still capable of being produced in the real world (using LEDs), and applied as growth light for plants—, this PAR spectrum being aggressive by comparison with the PAR spectrum of FIG. 2a for further narrowing the emission bandwidths in accordance with the present invention.

[0077] FIG. 2c is a graph showing just how narrowband a preferred spectrum of PAR in accordance with the present invention may theoretically be, with the PAR being produced and applied at but essentially a small number, nominally nine (9), individual wavelengths.

[0078] FIG. 2d is a graph again showing aggressive spectrum of PAR radiation previously seen in FIG. 2b juxtaposed against a typical prior art PAR spectrum of prior art grow lights.

[0079] FIG. 3a is a first schematic diagram of the driver of a real-world system using LEDs to produce PAR in each of multiple narrow bands in accordance with the present invention, which PAR was seen in the graphs of FIGS. 2b and 2d,

[0080] FIGS. 3b and 3c are second and third schematic diagrams of alternative connections of both (1) the driver of FIG. 3a, and (2) multiple LEDs, in order to produce the PAR in each of multiple narrow bands in accordance with the present invention, which PAR was previously seen in the graphs of FIGS. 2b and 2d.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0081] The subject of the present invention is the production, and the application, of Photosynthetically Active Radiation (“PAR”) where the PAR is very efficient to produce desired normal growth and maturation of the plants. An efficient PAR means that less energy—normally in the form of electricity—can be used to produce the PAR and the resultant plant growth. This is true no matter what the means of (narrowband) electrical illumination, although LEDs are strongly preferred,

[0082] Although a related patent application will teach another, independent, method of realizing an efficient and effective PAR, the efficiency gains of the present invention are essentially realized by production and application of (1) narrowband radiation (nominally ±5 nm, although as far as is known every single photon can have exactly the same wavelength (i.e., ±0 nm), about (2) each of a multiplicity of emission wavelengths, nominally nine such wavelengths. The (3) emission strength, or intensity, at each of the nominal nine (9) wavelengths can beneficially be different in flux intensity, and is nominally so different in ratios ranging from 1 to 3, and are more preferably in an approximate 3:2:1:1:2:4:2:1:1 ratio of flux magnitudes across the nine (9) nominal emission wavelengths.

[0083] A prior art graph showing the typical spectrum of absorption of light by a green plant, and the photosynthetic processes involved in this absorption, is shown in FIG. a1. Notably the plant primarily strongly absorbs light in the red and in the blue portions of the spectrum while absorbing relatively less (and thus reflecting relatively more) of the light in the green portion of the spectrum—although some green light is still absorbed. This pattern of absorption, and of reflection, is, of course, why most plants appear green in color.

[0084] A prior art graph showing a typical spectrum of PAR that has been applied (with various modifications) as growth light for plants in the prior art is shown in FIG. 1b. The absorption spectrums of the photosynthetic processes involving each of chlorophyll A, chlorophyll B, and the carotenoids have been recognized, and are included in the composite PAR spectrum that is graphed. In accordance with the spectral absorption of these photosynthetic processes, and some apparent degree of recognition that a green plant may absorb green light but this green light is of little, or no, use to plant growth, the prior art has, apparently quite reasonably, considered to supply (varying amounts of) both red and blue lights to a plant as PAR. The area under the curve in FIG. 1b can be integrated to derive the total light flux supplied, but whatsoever this prior art PAR light flux may in detail be, it has obeyed the simple principle that the plant should roughly be supplied with those wavelengths, and at those intensities, of PAR that it's photosynthetically active processes have been shown to absorb. Until the present invention this has arguably seemed to be a quite reasonable approach. Indeed, this prior art PAR has proven successful to induce satisfactory growth in a number a green plants.

[0085] The present invention is based on the discovery that this prior art PAR spectrum is by no means optimal—particularly in the amount of energy consumed but also, to a lessor degree, in the amount and speed and quality of growth induced in many plants. The PAR energy is represented by the integrated area under the intensity/flux versus wavelength curve of FIG. 1b, and this integrated flux roughly corresponds to the electrical energy used to produce it. (It only “roughly corresponds because, it will be understood that, by Plank's Law, the flux of shorter wavelength (i.e., the color blue) intrinsically takes more electrical energy to produce. Plus if and when the composite flux of FIG. 1b should be produced from narrowband emitters—such as LEDs—then some colors may be produced more efficiently than others. Consequently, the integrated flux only roughly relates to the electrical used to produce it.)

[0086] Now comes the present invention as illustrated in the graphs of FIG. 2, consisting of FIGS. 2a through 2d. It has been found that a green plant grows perfectly satisfactorily, even optimally for some species, when it is supplied with narrowband PAR at only a select number of wavelengths: potentially as few as four (4) or five (5) such wavelengths. However, as a practical matter, some nine (9) such wavelengths are preferred. The intensity of the light supplied at each of these nominal nine (9) wavelengths is usually some multiple, up to ten times (×10) but most normally about three times (3×), greater than the corresponding light intensity at these wavelengths within the prior art “broadband’ PAR. (The emission intensity at these nine wavelengths, and selected ones of them, can optionally be increased above normal levels to variously effectively (dependent upon plant type, maturation, other growing conditions, etc.) “supercharge” plant growth, although this is not required. Likewise, this ratio of from times three (×30 to times ten (×10) varies with the spectrum of the prior art PAR to which comparison is made—see FIG. 2d upcoming.)

[0087] However, and regardless that the new PAR in accordance with the present invention may be of greater intensity/flux than heretofore at each, and at any, of the preferred nine wavelengths, the total integrated flux—as roughly corresponds to the electrical energy used to produce this flux—under the emission spectrum of the new PAR—shown in FIGS. 2a and 2b—is greatly less than total; flux, and corresponding total electrical energy, used to produce the exemplary prior art PAR shown in FIG. 1b.

[0088] A crude spectrum of the new PAR in accordance with the present invention such as may readily be implemented with “off the shelf” Light Emitting Diodes (LEDs) is shown in FIG. 2a. A more refined, and preferred, spectrum of the new PAR as is implemented with the LEDs, and with the circuits, hereinafter described is graphed in FIG. 2b. An energy savings in the production of the PAR is immediately realized in both spectrums. Effectively no light illumination whatsoever need be delivered to most plants outside of narrowband light illumination(s) at each of the nominal nine (9) wavelengths. Any energy, commonly in the form of electricity, used to produce PAR radiation outside these nominal nine (9) spectral regions is effectively wasted for most plants. The total flux integrated under the curves of the preferred PAR—and the electrical energy used to produce this flux—is less for the PAR of the present invention, and is most commonly from times five (×5) to times ten (×10) less than the prior art PAR. Yet the illuminated plants illuminated with the new PAR of the present invention grow as well, or better, than with the PAR of the prior art.

[0089] Although the inventors cannot be held to render a correct scientific explanation of why their invention of the production and use of but narrowband PAR at each of multiple emission wavelengths works, it seems as if the processes of photosynthesis, and photochemistry, ultimately obey normal chemical equations, making that energy(ies) deviating from the preferred “center” energy of reaction are increasingly ineffective to promote the reaction, and are increasingly wasted. In simple terms, photosynthesis, and photochemistry, must be regarded first and foremost as chemistry—where it is well know that certain reactions proceed optimally at certain energies (and/or temperatures)—and only secondarily as photonics and photosynthesis. As has been previously explained, a chemical or a photochemical, reaction will proceed with energies, or photonic energies, that are deviating from, and different from, any single optimal energy, or photonic energy.

[0090] But, if artificial PAR, and “grow lights” are used, why give any plant other that the radiations that it can optimally use in its photosynthetic processes? It is thus the premise of, and the discovery behind, the present invention that PAR should be optimized to precisely what a plant requires for its photochemical and photosynthetic processes, and not, more crudely, all such PAR as the plant, and its said photosynthetic processes, can absorb.

[0091] A graph showing one, nominal, preferred spectrum of PAR—well capable of being produced in the real world (using LEDs)—applied as growth light for plants in accordance with the present invention is shown in FIG. 2a. Nine emission peaks A.sub.a-I.sub.a are visible. These peaks are preferably centered about (or the narrowband emission does at least contain) the following wavelengths: [0092] A.sub.a. 430 nanometers—first absorption peak of chlorophyll A [0093] B.sub.a. 450 nanometers—first absorption peak of both chlorophyll B and beta carotene [0094] C.sub.a. 480 nanometers—second absorption peak of beta carotene [0095] D.sub.a. 620 nanometers—absorption peak of phycocyanin [0096] E.sub.a. 640 nanometers—second absorption peak of chlorophyll B [0097] F.sub.a. 660 nanometers—second absorption peak of chlorophyll A and phytochrome [0098] G.sub.a. 670 nanometers—first wavelength involved in the Emerson effect [0099] H.sub.a. 700 nanometers—second wavelength involved in the Emerson effect. [0100] I.sub.a. 730 nanometers—first absorption peak of phytochrome

[0101] The emission intensity (which is nearly, but not exactly the same as the energy of emission E=hv] between each of the nominal nine wavelengths

[0102] A:B:C:D:E:F:G:H:I is nominally approximately in a 3:2:1:1:2:4:2:1:1 ratio, as is suggested by both the maximum heights of each emission peak, and the area under the curve at that peak, in FIG. 2a,

[0103] A new PAR of still better characteristics than those shown in FIG. 2a can be realized by the careful selection and interconnection of electrical components hereinafter described. This “better” new PAR—which may be considered “state of the art realizable by commercially available components circa 2012”—is diagrammed in FIG. 2b. Clearly the total integrated area under the nine (9) narrowband emission peaks is quite small if these peaks are even remotely of normal intensity/flux; which they are and which will be illustrated in FIG. 2d upcoming.

[0104] In accordance with the present invention, a graph showing just how narrowband a preferred spectrum of PAR in accordance with the present invention may carefully be made to be, with the produced and applied PAR being essentially at but a number, nominally nine (9), individual wavelengths, is shown in FIG. 2c. The vertical axis (and left scale) is RELATIVE INTENSITY, so the height of the peaks should not be compared with FIGS. 2a and 2b FIG. 2b simply shows that a practical—indeed, and optimally energy efficient—PAR may be generated and used when all the energy is within photons at, and of but arbitrarily narrow deviation about, but “two handfuls” of wavelengths, namely nine (9) such wavelengths. Although this curve is presently, circa 2012, impractical to realize—and could perhaps be realized only but with lasers—to the best knowledge of the inventors many common plants will grow if exposed to a PAR that contains photons of only nine wavelengths.

[0105] The energy savings of the present invention providing for the production, and the use, of PAR that is narrowband about only but a few wavelengths should be very evident from FIGS. 2a and 2b. Namely, all the energy that is within the PAR can be put at selected wavelengths, and there is no real need to illuminate at other wavelengths.

[0106] A graph showing how high are the intensity/levels of the extremely narrowband preferred spectrum of NEW PAR in accordance with the present invention is shown in FIG. 2d. The dashed line is the emission spectrum of a broadband halide grow light (i.e., a producer of PAR) circa 2012. The spectrum does not look much like the spectrum of the new PAR of the present invention, shown in solid line. Note that some intensity/flux peaks of the new PAR equal, and some exceed, the peak emissions of the PRIOR art PAR. However, the integrated area under old, and new, PAR spectrums—which integrated area is indicative of the energy cost to produce the PAR should the electrical lamps be of equal efficiency—greatly favors the new PAR. In actual fact the new PAR is produced by LEDs which are greatly more efficient in the amount of electricity consumed per unit light flux produced than are the broadband halide lamps used to produce the old PAR; making that the new PAR is more energy efficient in production as well as in its narrowband nature.

[0107] A first schematic diagram of the driver of LEDs to produce PAR in each of multiple narrow bands in accordance with the present invention, which PAR was seen in the graphs of FIGS. 2b and 2d, is shown in FIG. 3a. Second and third schematic diagram of alternative connections of (1) the driver of FIG. 3a and (2) multiple LEDs, in order to produce the new PAR of the present invention in each of multiple narrow bands—which PAR was seen in the graphs of FIGS. 2a and 2d—are shown in FIGS. 3b and 3c.

[0108] In these schematic diagrams of FIG. 3, a grow light assembly 1 typically consists of an indeterminate number, typically from one to ten, grow light sub-assemblies 1, 2, . . . N. The grow light 1, and the grow light sub-assembles 1, 2, . . . N are connected to, and between, alternating current (a.c.) power line L, neutral N, and ground G. A current driver 1, 2, . . . N produces direct current (d.c.) power sufficient, as respectively gated through PWM controllers 1, 2, . . . N, to power LED light strings 1, 2, . . . N.

[0109] Each sub-assembly normally produces but one, or two, PAR wavelengths, depending upon the grow room illumination intensities desired. The number of LEDs 1 through N in each string determines, along with the type of LED, the intensity, and the relative intensity, of the produced new PAR light. For example it may be recalled by reference to FIG. 2a that the relative intensities of the nominal nine wavelengths A:B:C:D:E:F:G:H:I was nominally approximately in a 3:2:1:1:2:4:2:1:1 ratio. If the LEDs of different colors each produce about the same light flux per current applied and consumed—which is very nearly the case—than a first narrowband spectral peak will be produced from 3 LEDs of about 430 nanometers emission wavelength, a second from 2 LEDs of about 450 nanometers emission wavelength, and so on.

[0110] UNIVERSAL AC (alternating current) power between line L and neutral N is nominally of magnitude 120 VAC. This UNIVERSAL AC is converted in POWER SUPPLY 11 to DC direct current) power between VDC (direct current voltage) and VDC-C (direct current voltage common). An individual POWER SUPPLY 11 typically powers a plurality of light strings 12, illustrated in FIG. 3 to be three in number light strings 12a-12c. The POWER SUPPLY 11 may be, for example, type HLG series available from Meanwell.

[0111] Each light string 12a-12c respectively consists of a CURRENT DRIVER 12a1-12c1, a POWER CONTROLLER COLOR CHANNEL 12a2-12c2, and a multiplicity of LEDs 12a3a-12a3n, 1223a-12b3n, and 12c3a-12c3n, The respective CURRENT DRIVERs drive the respective LED strings 12a3a-12a3n, 1223a-12b3n, and 12c3a-12c3n, The CURRENT DRIVERs 12a1-12c1 are 12 VDC constant voltage waterproof drivers. Rudimentary versions use resistors to bias current to desired levels. The preferred CURRENT DRIVERs 12a1-12c1 use constant current drivers to eliminate inefficient resistors and to drive longer strings of series-connected LEDs 12a3a-12a3n, 1223a-12b3n, or12c3a-12c3n.

[0112] This LED drive current for each LED string is gated through and by a respective POWER CONTROLLER COLOR CHANNEL 12a2-12c2. Each POWER CONTROLLER COLOR CHANNEL 12a2-12c2. consists of low voltage logic for developing a switching signal that is applied to an associated MOSFET power gating transistor to selectively intermittently energize an associated LED light string from the associated CURRENT DRIVER 12A1-12C1 in accordance with the related invention, and patent application. For the purposes of this invention, and this patent application, the CURRENT DRIVERs 12A1-12C1 may be considered to be continuously gating dc power from a CURRENT DRIVER 12A1-12C1 to an associated LED strings 12a3a-12a3n, 1223a-12b3n, or12c3a-12c3n.

[0113] The preferred LEDs of each LED string are:

TABLE-US-00001 Produces Identification base emissions numeral type including 12a3a, 12b3a, 12c3a Vollong 3 W High Power LED 430 nanometers 12a3b, 12b3b, 12c3b Vollong 3 W High Power LED 450 nanometers 12a3c, 12b3c, 12c3c Vollong 3 W High Power LED 480 nanometers 12a3d, 12b3d, 12c3d Vollong 3 W High Power LED 620 nanometers 12a3e, 12b3e, 12c3e Vollong 3 W High Power LED 640 nanometers 12a3f, 12b3f, 12c3f Vollong 3 W High Power LED 660 nanometers 12a3g, 12b3g 12c3g Vollong 3 W High Power LED 670 nanometers 12a3h, 12b3h, 12c3h Vollong 3 W High Power LED 700 nanometers 12a3i, 12b3i, 12c3i Vollong 3 W High Power LED 730 nanometers All LEDs are custom modified from the indicated base type by manufacturer Vollong Electronics Co., Limited, Wufang District, Jinxia, ChangAn Town, DongGuan, GuangDong, China.

[0114] LEDs of other types may be used for production of narrowband PAR at other wavelengths.

[0115] The connection of the driver of FIG. 3a as a CONSTANT CURRENT DRIVER 33 to multiple LEDs strings in electrical parallel is shown in the schematic diagram of FIG. 3b. The connection of the driver of FIG. 3a as a CONSTANT VOLTAGE DRIVER 12a1 to multiple LEDs 12a3 in electrical series is shown in the schematic diagram of FIG. 3c. Either connection can be used to produce the PAR in each of multiple narrow bands in accordance with the present invention, which PAR was previously seen in the graphs of FIGS. 2b and 2d.

[0116] As became clear during observation of the graphs of FIG. 2, the circuit of FIG. 3a results in generation of a PAR that is detectably distinct from all PAR of which the inventors are aware within the prior art. Namely, PAR in accordance with the present invention is noticeably concentrated at a limited number (nominally nine) emission peaks each at a different wavelength while an extensive portion of the absorption spectrum of the plant receives no PAR radiation at all. Indeed, still other portions of the PAR provided the plant receive—in accordance with how narrow an emission spectrum can be realized by a particular preselected LED existing in the real world circa 2012—but very little radiation. Although it is not gainsaid but that radiation falling within, and even outside, of a nominal ±5 nanometers wavelength, about any of the nominal nine (9) emission wavelengths can be used by the plant, there is not only no indication that this broadening of emission wavelengths—howsoever slight—is either useful or beneficial, but, indeed, it looks as if the plant could beneficially receive every single photon at but one of the nine nominal wavelengths, ±1 nanometers or ±0.5 nanometers or, should it be physically possible, even ±0 nanometers wavelength.

[0117] Consider what the means as regards the appearance, and the distinctiveness, of the spectrum of the most preferred PAR produced, and applied to plants, in accordance with the present invention. Essentially PAR emission can be a number of different wavelengths which not even overlap one another, let alone fill the entire wavelength spectrum (nor any substantial portion of it) from 360 nm to 760 nm. Energy savings are effected—regardless of the technology by which the new PAR is produced—from not providing PAR illumination into that portions of the spectrum where it is less effective, or even ineffective, to promote plant growth.

[0118] According to these variations, and still others within the skill of a practitioner of the artificial grow light, or PAR, arts, the present invention should be considered in accordance with the following claims, only, and not solely on accordance with those embodiments within which the invention has been taught.