ZALINGU NITRATU KIEKIO AUGALUOSE SUMAZINIMO, APSVITINANT KIETAKuNIO SVIESTUVO SUKURIAMU SVIESOS SRAUTU, BuDAS IR IRENGINYS

The present invention relates to plant cultivation where the plants are irradiated with a light flux produced by a solid state luminaire during or shortly after harvesting in order to direct the photosynthetic and metabolic processes still occurring in the plant in such a way as to reduce nitrate levels while preserving nutritional and other human properties. .

The present invention relates directly to the use of solid state radiation devices, such as light emitting diodes (LEDs), for the regulation of photosynthesis and metabolic processes in plants.

LEDs are non-coherent light sources based on injectable electroluminescence, which, unlike all other sources, do not require the material or its particles to be converted into light. Because the performance of LEDs is not limited by physical reasons, they can potentially be more efficient than other light sources. In addition, they have a number of advantages over conventional sources: they are mechanically robust, compact, durable, fast switching, do not burn suddenly, use low voltage, are easily compatible with computer electronics, emit in broad spectrum bands without extraneous spectral components, and contain no harmful substances (mercury), flexible with regard to mounting in various forms of matrices. As a result, LED-based solid state lighting technology is gradually penetrating all areas of artificial light use, such as light signals, displays, decorative, architectural, amusement, medical and general lighting, optical measurements [A. Žukauskas, MS Shur, R. Gaška, Introduction to Solid-State Lighting (Wiley, New York, 2002), xii + 207 pp., ISBN 0471215740],

Because the chemical composition of semiconductors used in luminaires can be easily matched to the absorption spectra of photosynthetic and photomorphogenetic pigments in plants, solid state illumination is an attractive technology for plant cultivation.

After the development of high-brightness red AlGaAs, it was proposed to increase the photosynthetic performance of plants by illuminating them with quasi-monochromatic light during cultivation, aligned with the major peak of the chlorophyll absorption spectrum (about 660 nm), thus avoiding losses from shorter length absorption. light waves [BulaR. J., Morrovv RC, Tibbitts TW, Barta DJ, Ignatius RW, Martin T. S., "Light-emitting diodes as a radiation source for plants," HortScience 26 (2), p. 203-205 (1991)].

U.S. Patent No. 5,012,609 (1991) has already defined three spectral bands in which a solid-state luminaire supporting plant growth and formation (morphogenesis) must emit: 620-680nm for photosynthetic needs of plants, 700760 nm for photomorphogenetic needs and 400-500 nm for to meet phototropic and photomorphogenetic needs. The same patent defines continuous and pulsed power supply for LEDs.

Subsequent patents describe various designs of luminaires and plant cultivation chambers (phytotrons). U.S. Patent No. 5,278,432 (2004) describes a construction of a luminaire consisting of a heat-conductive base with chips of luminaires attached thereto. Basic cooling means, including fan. The LEDs are powered by ballast-type electronic current stabilizers powered by a voltage source. U.S. Patent No. 5,278,432 (1997) defines the construction of a phytotron luminaire, where frame heaters are used to transfer heat from semiconductor chips and external reflectors are used to concentrate the light flux. Japanese patent applications [JP2004081110 (2004), JP2005000155 (2005)] offer solid state lighting cameras not only for growing plants but also for storing them. U.S. Pat. No. 6,688,759 (2004) defines a solid-state luminaire with luminaires arranged in several planes in the form of a chandelier.

U.S. Patents US 6,474,838 (2002), US 6,554,450 (2003) describe structures for phytotron sprouts, specifying wavelengths used and power supply circuits for LEDs. U.S. Patent No. 6,725,598 (2004) defines a phytotron camera with solid-state illumination that responds sensitively to environmental parameters, including illumination, and changes in plant parameters. The sensor signals are used to maintain and control environmental parameters.

Several patents are designed to take advantage of the specific benefits of LEDs. For example, European Patent EP 1374665 (2002) defines pulse power supply parameters for LEDs (from 2 to 1 ms and 20 to 70% duty cycle) for which optimum values ​​determine the highest productivity of the plant. U.S. Patent No. 6,921,182 (2005) utilizes spectral and directional flexibility in the emission of LEDs. Here the LEDs of different colors and directionality are adapted for uniform illumination of the upper and lower leaves of the plant, taking advantage of the wavelength dependence of the optical density of the leaves.

With the continuous advancement of luminaire technology, its power and price decline, solid-state illumination technology, derived from small phytotron cameras, has become attractive for large-scale industrial plant cultivation in greenhouses. European Patent EP 1300066 (2003) describes an industrial plant growing method in which the seed beds are conveyed by conveyor under an obliquely oriented solid body with a lighting plate so that as the height of the plant increases, the position of the light source rises evenly above the conveyor. The illumination panel consists of an air- or water-cooled metal (aluminum) base, an insulating layer with conductors, a reflector and clear plastic housing with a reflector and clear plastic body glued to the conductors by a conductive adhesive. The space between the lights and the cap is sealed and filled with dry inert gas.

European Patent EP 1479286 (2004), which is essentially the closest to the proposed device, describes a solid-state luminaire for complementing natural lighting in a greenhouse. The luminaires are mounted on a long and narrow ribbed radiator, which can be mounted on the structure of the greenhouse. Unlike previous patents, such a rail-mounted radiator design offers little obstruction to sunlight.

The aforementioned major patents and applications for the use of light bulbs for plant cultivation have a number of disadvantages that hinder the penetration of solid state lighting technology into industrial horticulture.

First, patents and patent applications often rely on claims that luminaires are more efficient than conventional light sources used in plant cultivation [US 5,012,609 (1991), EP1374665 (2002), EP1300066 (2003), EP1479286 (2004),

US 6,921,182 (2005)]. However, although the intrinsic quantum efficiency of light sources using electroluminescence injectable is theoretically not limited by physical reasons, the performance of commercially available LEDs is not high due to non-radiation recombination, the difficulty of light escape from refractive index material and, in some semiconductors (AlGaAs, AlGalnP) band gap influences [A. Žukauskas, MS Shur, R. Gashka, Introduction to Solid State Lighting (Wiley, New York, 2002), xii + 207 pp., ISBN 0471215740]. For example, the best high-power AlGaAs LEDs have a beam output of only 20% at 730 nm and no more than 10% at 660 nm; red (640 nm) AlGalnP and blue InGaN (450 nm) high power LEDs do not exceed 20% respectively; and

10% [G. Tamulaitis, P. Duchovskis, Z. Bliznikas, K. Breive, R. Ulinskaite,

A. Brazaitytė, A. Novičkovas, and A. Žukauskas, “High-power light-emitting diode-based plant cultivation,” J. Phys. D 38 (17), p. 3182-3187 (2005)]. It should be noted that the performance of these LEDs has grown very slowly in recent years. Meanwhile, the standard high-pressure sodium and fluorescent lamps widely used in glasshouses have a radiation efficiency of about 30%. It is true that due to the ability to better match the emission spectrum of LEDs with the absorption spectra of phytopigments and the advantage of pulsed illumination, plant productivity using solid-state illumination can be about 1.5 times higher [EP1374665 (2002); G. Tamulaitis, P. Duchovskis, Z. Bliznikas, K. Breive, R. Ulinskaitė, A. Brazaitytė, A. Novičkovas, and A. Žukauskas, “High-power light-emitting diode-based facility for plant cultivation,” J. Phys. D 38 (17), p. 3182-3187 (2005)]. However, the operating costs of solid-state lighting in plant cultivation are only slightly lower or even higher than the operating costs of conventional lighting. In addition, given the substantial cost of solid-state lighting at several times the total cost of a conventional, LED-generated light flux, their use in industrial plant cultivation throughout the vegetation cycle, as proposed in most related patents, is still economically unattractive.

Second, there is a widespread belief that LEDs generate less heat than conventional sources [US 6,474,838 (2002), EP1374665 (2002), US 6,554,450 (2003)]. The actual plants used for cultivation do not directly emit far infrared because their chip temperature is low. However, due to internal energy losses, they release thermal energy which must be led to the radiator. Although the latter is usually colder than the discharge or fluorescent tube, due to the large radiator area, the thermal radiation flux is no less than that of conventional sources. On the other hand, this goes without saying, because the luminous efficiency of LEDs is low and all the non-light energy is converted into heat. Therefore, placement of solid-state lighting panels close to plants is not always warranted and can cause overheating of plants.

Third, because of the high unit cost of the light output generated by the LEDs, even small losses are undesirable. Meanwhile, a number of patents offer voltage circuits with a voltage stabilizer (requiring a ballast resistor [US5012609 (1991)]). Meanwhile, in order to stabilize the current through the diode circuit, the voltage drop across the ballast resistor must be much greater than the voltage drop across the diode circuit. With electronic ballast [US 5,278,432 (2004)], the losses are smaller but still significant.

Another common type of loss is optical loss due to improper construction of the protective cap - a transparent glass or plastic plate between which air or other gas is left between the plastic capsule of the luminaire [US 5 278 432 (1994), EP1300066 (2003), US 6 725 598 ( 2004)]. When light falls perpendicularly to such a plate, 8-10% of the flow is reflected, and at a greater angle of incidence the losses increase. For high power luminaires, which typically have a wide beam angle, the loss due to reflection from the flat cover can reach 20% or more.

Fourth, developers of solid-state plant lighting systems generally do not consider the drop in flux generated by LEDs due to temperature changes and aging. Conventional luminaire power systems have a current measurement feedback that provides current stabilization [e.g., US6724156 (2004)]. Meanwhile, changing the junction temperature in the red AlGalnP red LED from 10 ° C to 60 ° C reduces the luminous flux by 30%. As the additive ages, the life-time flux drops gradually to 50-70% of its initial value. In some patents, thermal and aging drift can be compensated by a computer or microprocessor control system [EP1300066 (2003), US6725598 (2004)]. Analog power supply for LEDs [US7019662 (2006), in which photoelectric feedback maintains a constant output current, does not protect LEDs from overcurrent, and does not provide constant illumination. a mode that simultaneously provides a steady photosynthetic flux of photons and an overcurrent protection of the LEDs.

As long as economic reasons prevent solid-state illumination for plant cultivation throughout the growing cycle, the benefits of LEDs can be applied to short-term irradiation of greenhouse plants, such as during germination, for example, germination [US 6,474,838 (2002), US 6,554,450 (2003)]. or for altering the level of phytochemical compounds [EP 1626620 (2004)].

On the other hand, there is a need to improve the nutritional quality of already grown greenhouse plants by reducing nitrate levels. Such increased levels of nitrate are common in plants grown under artificial light using fertilizers, because for economic reasons and because of the strong radiation from conventional sources, artificial light photosynthetic photon flux (about 100 µm *²s^_1) ch

is much smaller than natural sunlight (up to 2000 pmol rn ^ s^-1). In addition, the increased nitrate content is also due to the fact that the spectrum of conventional lamps is not well adapted to the plant's photophysiological needs, the photoperiods used are optimized not according to the plant needs, but the daily electricity price variation, artificial fertilizer content in soil or nutrient medium. to get the maximum productivity of the plant, etc. The method of reducing the amount of nitrate nitrogen in vegetables by lighting them is known. However, with conventional light sources, the illumination cannot be high and vegetables must be processed for a long time. For example, Japanese Patent Application JP2005245243 (2005), which describes a method for reducing harmful nitrate residues by illumination, proposes the use of illumination starting at 300 lx (corresponding to approximately 5 µmol / m).²s^_1 photosynthetic photon flux), and illuminate the vegetables for at least 3 days and nights before and / or for at least 7 days after harvest. Long processing times can lead to deterioration of other nutrient properties of vegetables due to aging, improper photoperiod, and so on. Too low light levels can even increase nitrate levels.

The closest proposed method of reducing harmful nitrate residues in plants by irradiation with a solid-state luminaire is a method for reducing harmful nitrate residues in plants by irradiating plants with the above-mentioned Japanese Patent Application JP2005245243 with the above disadvantages.

The closest embodiment of the proposed method for reducing the harmful nitrate content of plants by irradiation with solid-state light flux is a plant-irradiated photosynthetic light-emitting device according to the aforementioned European Patent EP1479286, consisting of a solid-state luminaire. Such an elongated radiator is designed to obscure the sunlight for the plants as little as possible, but the problem of overheating of plants due to the increased light flux is not solved. This unit is designed to complement natural lighting but is not designed for efficient nitrate reduction.

The object of the invention is to provide a method and a device for reducing the amount of harmful nitrates of the grown plants without reducing their nutritional composition, especially without reducing the amount of useful sugars and vitamins.

The objective is achieved by reducing harmful nitrates in plants by irradiating the plants with a photosynthetic flux emitted by a solid state luminaire. What is new is that plants are irradiated with photosynthetic flux for up to 3 days after growth or in the post-harvest stage. The density of the photosynthetic photon flux is regulated from 100 to 2000 pmoFm^-2^^-1 in the wavelength range 400 to 700 nm with a photoperiod of 12 to 24 hours, directing the thermal radiation of the luminaire radiator to the opposite side of the treated plants.

Alternatively, the plants are subjected to photosynthetic photon flux treatment after growing or in the harvesting stage for up to 3 days, regulating the photosynthetic photon flux density from 40 to 2000 pmol-m^_2s^-1, in the wavelength range 400 to 700 nm with a photoperiod of 12 to 24 hours, directing the radiant heat of the luminaire radiator to the opposite side of the plant being treated by changing the environmental conditions

the gas composition (CO2 concentration) of the surrounding environment, and

reducing the concentration of the nutrient solution during the harvesting phase, or

- lowering the ambient temperature to 4-25 ° C.

For example, ambient gas may contain 0.05-0.3% CO2, nutrient concentration reduced to 0-33%, ambient temperature 20-25 ° C. The density of photosynthetic photon flux can then be reduced to 400-600 pmol-. rn^-2^“¹ in the wavelength range 640 nm to 660 nm for a photoperiod of 18 hours.

Optimally, it is proposed to reduce the adjustable density of the photosynthetic photon flux to 40-100 pmol nT s by lowering the ambient temperature to 4 ° C, without necessarily altering other environmental conditions.

The proposed method of reducing harmful nitrate residues in plants by irradiation with a solid-state luminaire is accomplished by a device consisting of a luminaire consisting of one or a plurality of luminaires arranged on an elongated radiator to accommodate the plants for irradiation and a power source for the luminaires. What is new is that said radiator is made elongated with one or more ridges, which may be continuous or perforated or needle-facing, away from plants, and the surfaces of the rib walls are treated to maximize the thermal radiation coefficient of the ridges. The underside of the radiator on which the lights are mounted is much smaller than the area of ​​the edges, and the underside is treated so that its coefficient of thermal radiation is minimal. The bottom of the radiator, together with the lights, is covered with a transparent cover.

The clear cap consists of hemispherical segments centered on the chips of the LEDs, and the space between the cap and the clear capsules of the LEDs is filled with a transparent grease or resin with a refractive index similar to that of the cap body and the capsules.

The power supply scheme includes a pulse voltage converter, the output voltage of which is controlled by two feedback loops (photoelectric and protective) which are switched by an electronic commutator, depending on which of the two sizes (total ambient and luminescent photosynthetic photon flux density or power supply).

The photoelectric feedback loop consists of a photoelectric meter consisting of a photodiode with an optical filter and a first operational amplifier with a resistive feedback loop, a second operational amplifier and a first potentiometer, and an optical filter's optical bandwidth (400 to 700 nm). spectral sensitivity, such that the output voltage of the first operational amplifier is proportional to the density of the photosynthetic photon flux, and a protective feedback loop has a third operational amplifier coupled to a measuring resistor connected in series with the light circuit and a second potentiometer.

The feedback loop switch consists of two silicon diodes and a resistor connected to a fourth operational amplifier, where the anodes of said diodes are connected to the output of the second (photoelectric control) and third (protective control) operational amplifiers respectively and the cathodes are connected to the resistor.

The luminaries that make up the luminaire emit at one or more wavelengths in the wavelength range 400 - 700 nm.

Advantages of the proposed technical solution.

The proposed method of reducing harmful nitrogen fertilizer residues in plants by irradiation with solid-state light fluxes is that the irradiation is effected by high-density photosynthetic photon flux and achieves nitrate reduction effect within a shorter time (no more than 3 days) without reducing plant nutrition quality.

By treating already formed and grown plants with high-density photosynthetic photon fluxes, nitrate residues accumulated in the leaves of plants during intensive cultivation are rapidly reduced by photochemical reactions that additionally produce nutrients such as various sugars (fructose, sucrose, etc.), C, folic acid, etc.), phytohormones (zeatins, indoles, etc.), etc. In this way, the plants reach the harvesting terminal with reduced residual nitrate content and possibly even increased nutrient content and are presented to the consumer in this form. Alternatively or additionally, plants, especially their leaves, can be subjected to high-density photosynthetic photon flux after harvest.

Because processing with high photosynthetic photon fluxes takes a short time compared to the total vegetation time, the high cost of light produced by solid-state luminaires has a relatively small influence on the cost of vegetables. In addition, for each type of vegetable, the cost of additional irradiation can be minimized by selecting the optimal light spectrum for photosynthetic photon flux density, irradiation duration, and photoperiod.

The high-density photosynthetic photon flux is produced by a device for implementing the above method, which utilizes high power LEDs with a spectral spectrum compatible with the absorption spectrum of chlorophylls. The luminaires are mounted on the radiator, covered with a transparent protective cover and connected to the power supply. The lighting system is designed so that plants are exposed to minimal heat radiation and the unit cost of photosynthetic photon flux is the lowest.

The above embodiment of the method differs from a number of aspects used hitherto. First of all, the construction of the radiator is specially adapted to direct the powerful thermal radiation generated at the same time by generating high-density photosynthetic photon fluxes away from the plant to prevent them from overheating. This design is fundamentally different from the designs described in the patents [e.g., US 5,012,609 (1991), US 5,278,432 (1994), EP 1300066 (2003), US 6,688,759 (2004)], wherein heat-conducting continuous lamps are used. panels and a significant part of the thermal radiation enter the plants. The present invention employs, as in European Patent EP 1479286 (2004), a narrow rail-shaped radiator with bottom-mounted lights. However, the purpose of the radiator is not only to obstruct external natural or artificial lighting, but also to ensure the lowest possible thermal radiation towards the plants. In the present invention, the radiator is provided with some form of ribs deflecting the thermal radiation away from the plant and their surface is treated to maximize its thermal radiation coefficient. Meanwhile, the narrow bottom of the radiator closest to the plants is treated so that its coefficient of thermal radiation is minimal.

The second aspect concerns the reduction of optical losses in the luminaire in order to make the proposed method more commercially attractive. Such losses occur with the use of a flat protective cap [US5278432 (1994), EP13OOO66 (2003), US6725598 (2004)]. In the absence of a cover such as that in the application [EP 1479286 (2004)], the luminaires and the electrical circuits connecting them are unprotected from moisture and the luminaire is difficult to clean from dust and insect pollution. The present invention employs an airtight transparent cover consisting of hemispherical segments centered on luminaire chips. A special feature of this cap is that the gap between the cap and the clear capsules of the LEDs is filled with translucent grease or resin to improve optical contact.

The third aspect of the luminaire design concerns the power supply, which must provide low operating costs. For this, it has to be characterized by low power losses and electricity savings at the expense of natural lighting. The luminaires must also be protected against excess current, which reduces their lifetime. The analogs of the proposed power supply include a pulsed AC voltage converter with constant current stabilization [US 6,724,156 (2004)] and a LED circuit with output current stabilization [US 7,019,662 (2006)], but the present invention utilizes an analog dual feedback circuit, simultaneously limiting the supply current or the total flux generated by natural light and luminaires, above the limit Analogue dual feedback loop for controlling the light source is disclosed in U.S. Patent US2005088102 (2005), wherein the illumination is controlled within the optimum temperature of the lamp by optical or thermal feedback, respectively. Thus, the power scheme of the present invention is more economical than ballast resistors [US5012609 (1991)] or electronic ballast [US5278432 (1994)] and pulsed power supplies with current stabilizing feedback [US6724156 (2004)]. On the other hand, in comparison with power supplies with output stabilizing feedback [US7019662 (2006)], the proposed scheme is safe in terms of LED overload. Finally, it is simpler than the numerical methods described in [EP1300066 (2003), US6725598 (2004)]. The proposed solid-state luminaire power supply with analog dual feedback loop is more economical, self-compensating for the temperature and aging drift of the flux generated by the luminaires, and is safe against overloading the luminaires.

The invention is explained in the drawings, in which:

FIG. 1 is a general view of the device;

FIG. 2 - a) - general view of the luminaire, b) - cross-sectional view of the luminaire;

Fig.3 - Schematic of power supply;

FIG. 4 - Schematic diagram of the application of the proposed method in the greenhouse;

FIG. 5 - typical variation of nitrate concentration in lettuce and marjoram with solid-state illumination according to Table 1;

FIG. 6- typical variation in the concentration of nutritional quality parameters (vitamin C and sugars) in lettuce and marjoram with solid-state illumination, as shown in Tables 2 and 3;

FIG. 7 - Changes in the concentration of vitamin C and sugars in nitrate irradiation with solid-state illumination under modified ambient conditions (reduced to 4 ° C) according to Table 4.

FIG. 8-radiator ribs shape: a) continuous, b) continuous perforated, c) needle.

In the proposed method of reducing harmful nitrate residues by irradiating the luminous flux generated by a solid state luminaire, plants are treated with high-density photosynthetic photon flux for a short period (up to 3 days). The density of the photosynthetic photon flux is regulated from 100 to 2000 μπιοΙ-ηΓ²^^-1, in the wavelength range 400 to 700 nm with a photoperiod of 12 to 24 hours, directing its thermal radiation to the opposite side of the treated plants.

In order to reduce the flux density to 40 - 2000 μπιοΙ-πί ^ -ΗΓ / η siūl ^, it is proposed to perform the method described in the previous paragraph by changing at least one of the environmental conditions during the treatment period: ambient gas composition (eg CO2 concentration), or, approaching the harvest stage by reducing the concentration of the nutrient solution and / or maintaining the ambient temperature within the range of 4-25 ° C.

For example, by increasing the amount of CO2 in the ambient gas to 0.05-0.3%, reducing the concentration of the nutrient solution to 0-33% and maintaining the ambient temperature at 20-25 ° C, it is proposed to reduce the flow density to 400-600 µmol.^-2^^-1 in the wavelength range 640 nm to 660 nm with a photoperiod of 18 hours.

Ideally, it is proposed to reduce the flow density by optimally reducing the ambient temperature to an optimum temperature of 4 ° C by 40-100 µm m V, without necessarily altering other environmental conditions.

The embodiment of the method consists of a luminaire 1 (Fig. 1) consisting of one or a plurality of high-power luminaires 2 spaced on the underside of an elongated profiled radiator 3. The radiator is elongated with one or more ribs 4 facing upward from the plants. The edges 4 of the radiator 3 are high relative to the width of the radiator and are directed upwards in the opposite direction from the beds 5 with plants 6 placed beneath it. The edges 4 are provided with holes 7 for mounting the luminaire. It is most convenient to use an aluminum alloy radiator. The edges of the edges 4 are painted or anodized to increase the coefficient of thermal radiation to obtain a black color. The radiator edges 4 may be continuous (Fig. 8-a,) or perforated (Fig. 8-b,) and additionally re-ribbed to provide an area. the radiator can also be made of a plurality of (narrow element) needles (Figs. 8-c,) facing away from the plants. Meanwhile, the bottom of the radiator 8, which is directed towards the plants 6 and on which the lamps 2 are mounted, shall have the lowest coefficient of thermal radiation. In the case of aluminum alloy, this is most easily achieved by polishing the bottom surface of the radiator 8. The lights 2 are fixed to the radiator 3 with heat-conductive glue. Such a radiator is needed to prevent the LEDs 2 from overheating when generating a high luminous flux. Overheating of LEDs 2 will reduce radiant performance and lifetime, and hot LEDs 2 chips will radiate heat toward plants, which is undesirable. The radiator 3 is configured so that the temperature of the semiconductor junctions of the LEDs 2 is not higher than the ambient temperature by more than 20 ° C, and the thermal radiation generated by the radiator is diverted away from the plants to prevent them from overheating. The low junction temperature of the LEDs 2 is achieved by proper selection of the radiator area 3 and the shape of the ribs 4. Meanwhile, not only the shape of the radiator, but also its orientation and coefficients of thermal radiation on different surfaces are important for directing the thermal radiation away from the plant.

Because the width 8 of the bottom 8 of the radiator 3 is small relative to the entire circumference of the radiator 3, the flow of thermal radiation directed downward toward the plant 6 is small. The plants 6 thus treated in the troughs 5 are protected from overheating. Meanwhile, most of the heat is radiated and transmitted due to the convection of air between the radiator edges 4 mainly vertically upwards. In addition, the narrow radiator 3 offers little obstruction to the natural light coming through the roof of the greenhouse.

The lights 2 (Fig. 2) placed on the bottom 8 of the radiator 3 are covered by a cover 11 made of a transparent material (plastic, for example, stabilized polycarbonate). It consists of hemispherical segments 10, which are the same as the number of LEDs 2 in the luminaire 1. The hemispherical segments 10 are integrated with the body of the cap 11. In the luminaire, it is desirable to use high power LEDs 2, which usually consist of a base 12 with a heat transfer tray 13, a semiconductor chip 15 on the base 12 in a reflector cup, and a plastic or silicone capsule 16. Depending on the construction of the luminaire 2, its base 12 may be mounted on a plate which is heat-conductive (metal) on one side and electrically insulated with printed electrodes soldered to terminal 2 of the luminaire 17. The cap is made such that each hemispherical segment The geometric center of 10 would be at the chip chip 15. In this way, the light emitted by the lamp 2 would fall predominantly perpendicular to the surface of the cap and experience the least reflection. When the gap 18 between the LED capsule 16 and the hemispherical segment 10 is filled with material having a refractive index similar to plastic (1.5-1.6), the reflections within the boundary between the LED capsule 16 and the gap 18 and between the said gap and the hemispherical segment 10 of the cap are almost removed. In this case, it is most convenient to use translucent soft grease or resin (for example, silicone), which lubricates the capsules of the lamps during installation 16. Such a cover design allows to reduce the optical loss of luminaires with a wide spatial radiation distribution from about 20% to less than 10% compared to the known flat cover. The optical loss is further reduced by the polished radiator bottom 8, where the lights 2 are mounted. (Part of the light reflected from the cover surfaces is reflected by the polished radiator surface and may escape the lamp a second time. The housing 11 of the cap is attached to the radiator (e.g. by screws) and sealed (eg by transparent sealing adhesive). It is intended to protect the luminaires 2 and the electrical circuit between them from moisture and to facilitate cleaning of the luminaire against dust and insect pollution. The construction and fastening features of the cover are such that the optical losses are minimal. As the unit cost of light flux generated by LEDs 2 is high, the reduction of optical losses is important for the commercial attractiveness of the proposed method. The LEDs 2 are connected to one or more parallel circuits 9 and connected to a power supply (Fig. 3).

The power supply of the luminaires 19 is characterized by minimal power loss, which ensures the minimum operating costs of the luminaire and the possibility to save electricity at the expense of natural lighting. Since the LEDs require a constant electrical current to supply, it is most efficient to use a pulse voltage converter for power supply. The smallest losses are provided by pulse voltage converters with feedback stabilization without ballast. Such a power source allows you to save electricity at the expense of natural lighting by reducing power supply. At the same time, the design of the power supply provides for the protection of the lamps against overcurrent.

The power supply 19, schematically shown in Fig. 3, consists of a standard pulse voltage converter 20 which converts AC power from the mains at input 21 to direct current at output 22. The efficiency of such converters can reach 90% and more. The invention uses a voltage converter which has a voltage stabilization circuit. This circuit is usually connected to a resistor voltage divider at the output of the converter. In the present invention, the power supply scheme (FIG. 3) this circuit is disconnected from the voltage divider and connected to the outlet 23 which is used to control the output voltage by means of feedback. For the sake of certainty, a transducer is selected in which increasing the voltage at output 23 decreases the output voltage at output 22 and vice versa.

A feature of the power supply circuit diagram (Fig. 3) is two feedback loops. A single feedback loop is used for photoelectric regulation to maintain a constant photosynthetic flux flux. Another feedback loop is used to protect the LEDs from overload by limiting their power supply current to the maximum allowable value. The two feedback loops are switched by a diode switch.

The photoelectric control feedback loop comprises a photoelectric meter 24 and a regulating second operational amplifier 25. The photoelectric meter 24 comprises a photodiode 26 with an optical filter 27 and a first operational amplifier 28 with a resistive feedback loop. The optical transmission spectrum (400 to 700 nm) of the filter 27 is matched to the spectral sensitivity of the photodiode 26 such that the output voltage of the first operational amplifier 28 is proportional to the density of the photosynthetic photon flux. This voltage is supplied to the non-inverting input 25 of the second operational amplifier. Meanwhile, a bias voltage is applied to the inverting input of the second operational amplifier 25, which is determined by a first potentiometer 29 connected to a reference voltage V_REF source. The shift voltage is set to equal the voltage at the non-inverting input when the value of the photosynthetic photon flux is of the required magnitude.

The protective control feedback loop consists of a measuring resistor 30 and a third operational amplifier 31. The measuring resistor 30 is connected in series with the LED circuit 9, and the voltage dropping thereon is proportional to the current flowing through the LED circuit 9. This voltage is supplied to the non-inverting input 31 of the third operational amplifier. a bias voltage is applied to the inverting input of the third operational amplifier 31 which is determined by a second potentiometer 32 connected to a reference voltage Vref source. The offset voltage is set so that it is equal to the voltage falling on the measuring resistor 30 when the maximum allowable current is flowing through the LED circuit 9. The power loss due to voltage drop on the measuring resistor can be negligible as this voltage drop must not significantly exceed the input shift voltage (~ 1 mV) of the third operational amplifier 31 and its drift within the operating temperature range (-0.1 mV). For example, if the output voltage of the converter 30 is about 36 V and the maximum voltage drop on the measuring resistor 30 is 100 mV, the loss will not exceed 0.3%.

The feedback loop switch consists of silicon diodes 33 and 34, resistor 35 and a fourth (switching) operational amplifier 36. The anodes of the diodes 33 and 34 are connected to the second and photoelectric control third operational amplifiers 25 and 31, respectively, and the cathodes are connected. with resistor 35. Thus, the voltage drop across resistor 35 is the greater of the two control voltages. For example, if the output voltage of the second operational amplifier 25 is V_P is higher than the output voltage Ve (V_P > Ve), then diode 33 will be opened and diode 34 will be closed. In this case, the voltage drop across resistor 35 will be approximately V_POtherwise, if (V_P<Ve), the voltage drop on resistor 35 will be approximately V_c- 1 V. Voltage drops on resistor 35 fed to non-inverting input of fourth operating amplifier 36. A fourth operational amplifier 36 is coupled to a voltage repeater circuit and its output is coupled to the control input 23 of the pulse converter 20.

EXAMPLE. A specific embodiment of the method of the invention using the device of the invention.

At the greenhouse planting terminal (Fig. 4), leafy vegetable sprouts 6 are planted in troughs 5, which feed the nutrient fluid. Here, leafy vegetables can be a variety of plants with edible parts of leaves or chlorophyll-bearing organs: lettuce, onion leaves, leeks, various kale, spinach, parsley, cauliflower, chard, leaf turnip, broccoli, mustard, dill, basil, green peas , wheat, barley, cucumbers, etc. The troughs 5 with the seedlings 6 are evenly transported by the conveyor towards the harvesting terminal 37 so as to reach it during the growing cycle (2CM0 days). During cultivation, the plants are exposed to natural light from the transparent roof of the greenhouse and, in addition, to electric lighting 38, which may incorporate high-pressure sodium, fluorescent, mercury, metal halides or other conventional lamps 39. These lamps are hung high so that the light they produce is evenly distributed and plants are not overheated by thermal radiation. Lamp-induced photosynthetic photon flux density is, as usual, about 100 pmol-m ^ -s', and the photoperiod can range from 12/12 hrs. up to 24/0 hours.

At harvest terminal 37, troughs with already formed and grown plants 6 fall under solid light fixtures 1 and are evenly transported beneath these light fixtures until they reach harvest terminal 37. During this technological phase, the amount of fertilizer in the feed liquid can be partially reduced or fertilization completely stopped. Solid-state luminaires 1 emit a high-density photosynthetic flux stream in the 400-700 nm wavelength range. The irradiance spectrum can be composed of one or more radiation bands whose peaks are in a given spectrum band. The luminaires 1 are hung low to reduce the losses due to side radiation and thereby reduce light pollution (unwanted light output through the walls and roof of the greenhouse). The design of the luminaires 1 ensures that their thermal radiation towards the plants is low enough to prevent the plants from overheating. The density of the arrangement of the luminaires is such that the maximum density of the generated photosynthetic photon flux is from 40 pmolm^-2s^_I up to 2000 um²s^-1, depending on the type of plant, duration of irradiation and environmental conditions. The duration of irradiation may be from 1 to 3 days and the photoperiod from 12/12 hours. up to 20/4 hours

To save electricity costs and extend the lifetime of the luminaires, the flow generated by the luminaires 1 is controlled by a photoelectric meter 24 placed adjacent to the growing cot connected to the luminaires power supply 19. It is controlled as follows. Suppose that the current flowing through the light circuit 2 does not exceed the maximum allowable. The voltage at the output of the operational amplifier 31 is then low, and the diode 34 is closed. The output voltage of the converter 20 is controlled by a photoelectric feedback loop such that the voltage between the inputs of the second operational amplifier 25 is nearly zero, its output has a positive control voltage, and diode 33 is open. As the density of the photosynthetic photon flux decreases or increases, the control voltage varies so that this decrease or increase is compensated by an increase or decrease in the LED current, respectively. However, if the supply current reaches the maximum allowable value, a high voltage occurs at the output of the third operational amplifier 31, diode 34 opens, and diode 33 closes. The output voltage of the inverter 20 is then controlled by a protective feedback loop such that the voltage between the inputs of the third operational amplifier 31 is nearly zero and its output has a positive control voltage. Since, in this case, the density of the photosynthetic photon flux is lower than that set, the voltage at the output of the second operational amplifier 25 is low and diode 33 no longer opens. If the density of the photosynthetic photon flux increases to a set value (for example, external lighting or the diodes cool), the feedback loop switches to the photoelectric control and the power supply to the LEDs decreases.

Thanks to the photoelectric feedback, this power supply scheme compensates for the temperature and aging drift of the flux generated by the LEDs and saves electricity under external lighting.

The power supply control diagram (Fig. 3) and the spectral sensitivity of the photoelectric cell ensure that the total artificial and natural photosynthetic photon flux is constant and of the set value. This means that on a sunny day the luminous flux generated by the luminaires can be reduced to a minimum and during the dark hours the luminaires will generate the maximum set flow. However, the power supply of the LEDs may not exceed the maximum permissible value in any case, in order not to reduce their lifetime.

EXAMPLE. Evaluation of plant nutritional quality by irradiation with light flux generated by solid.

FIG. 5 shows typical changes of nitrate concentration in leafy vegetables (GRAND RAPIDS lettuce and marjoram "MAIRŪNAI KVAPIEJI") at the stage of technical maturity. Nitrate concentration was measured immediately after culturing and after 2 and 3 days of irradiation with solid state illuminator 1 according to the procedure of Example 1. Cultivation was carried out by irradiation with sodium lamp at a density of 100 µmol for 30 days.^_2s^_1 and for photoperiod 18/6 h. During cultivation the temperature was 21/17 ° C (day / night). The treatment was carried out by irradiation with 640 nm spectral wavelengths at 500 pmol m '²s^-1 and for photoperiod 24/0 h. Lettuce was grown by hydroponic feeding and marjoram was grown on a solid substrate. Nitrate concentration was determined by potentiometric method with a nitrate ion selective electrode. Table 1 gives numerical values ​​of nitrate concentrations.

table. Nitrate concentration (mgkg^-1) in lettuce and marjoram immediately after cultivation and after irradiation with a solid-state illuminator

The plant

<td>Immediately after cultivation</td><td>irradiated for 2 days</td>

<td>by irradiation with a sodium lamp</td><td>solid-state luminaire</td>

irradiated for 3 days with a solid-state illuminator

<td>Salad</td><td> 4274±18</td><td> 2441±76</td><td> 1513±82</td>

<td>Mairunas</td><td> 1364±32</td><td> 790±28</td><td> 563±25</td>

FIG. Tables 5 and 1 show that the nitrate concentration in vegetable leaves under solid cells is noticeably reduced (almost twice) after 2 days, and after 3 days it is 2.4-2.8 times lower than immediately after cultivation. These results indicate that the present invention achieves a noticeable reduction in nitrate in a much shorter time than the patent application [JP2005245243 (2006)].

FIG. Tables 6 and 2 and 3 show typical results of biochemical analysis of control and irradiated solid-state plants - changes in vitamin C and monosaccharides (fructose, glucose) and disaccharides (sucrose, maltose). The higher content of these substances indicates the higher nutritional quality of the vegetables. In addition, changes in the composition of sugars as the ratio of disaccharides to monosaccharides decreases is an additional positive indicator of nutritional quality, as monosaccharides are more easily absorbed. Measurements were made on the same plants and simultaneously with the nitrate concentration measurements as in Fig.5. The concentration of vitamin C was determined by titration with the sodium salt of 2,6-dichlorophenolindophenol and the concentration of sugars by high performance liquid chromatography (HPLC). 2 Tables 3 and 3 give numerical values ​​of measured vitamin C and sugars concentrations.

table. Vitamin C concentration (mg%) in lettuce and marjoram immediately after cultivation and after irradiation with solid-state light (Fig.6)

<td>The plant</td><td>Immediately after cultivation by irradiation with a sodium lamp</td><td>irradiated for 2 days solid-state luminaire</td><td>irradiated for 3 days solid-state luminaire</td>

<td>Salad</td><td>12.3 ± 0.1</td><td> 18,2±0,2</td><td> 16,2±0,2</td>

<td>Mairunas</td><td>13.7 ± 0.1</td><td>17.5 ± 0.1</td><td>17, l ± 0, l</td>

table. Sugar concentration (mg · g ') in lettuce and marjoram immediately after cultivation and after irradiation with solid-state light (Fig.6)

<td>The plant</td><td>sugar</td><td>Immediately after cultivation by irradiation of sodium lamp</td><td>irradiated for 2 days solid state light fixture</td><td>After irradiation for 3 days solid state light fixture</td>

<td rowspan="3">Salad</td><td>Fructose (mono-)</td><td>1.25 ± 0.16</td><td> 3,17±0,26</td><td> 4,57±0,08</td>

<td>Glucose (mono-)</td><td> 0,97±0,16</td><td> 0,26±0,02</td><td> 0,37±0,02</td>

<td>Maltose (di-)</td><td> 0,48±0,01</td><td> -</td><td> -</td>

<td rowspan="3">Mairunas</td><td>Fructose (mono-)</td><td>1.23 ± 0.13</td><td>l, 61 ± 0, ll</td><td>l, 89 ± 0.10</td>

<td>Glucose (mono-)</td><td> 4,68±0,05</td><td> 6,89±0,05</td><td> 7,67±0,05</td>

<td>Maltose (di-)</td><td>1.97 ± 0.06</td><td> 2,01±0,07</td><td> 2,08±0,08</td>

From FIG. Tables 6 and 2 show that vitamin C content in lettuce and marjoram increases by 1.3-1.5 times after 2 days of solid state illumination. Later (after 3 days), vitamin C levels do not increase or decrease slightly.

FIG. Tables 6 and 3 show a significant increase in monosaccharide fructose concentration in lettuce by solid-state illumination. Despite a slight decrease in the glucose concentration of the other monosaccharide, the total monosaccharide concentration increases more than 2-fold after 3 days of irradiation. Meanwhile, the maltose concentration of nutritionally less valuable disaccharide is reduced to practically zero. This indicates that not only does the sugars in the salads irradiated with solid-state light not deteriorate, but also significantly improves.

FIG. Tables 6 and 3 also show similar results for marjoram. In this case, the maltose concentration of the disaccharide remains almost unchanged, but the total concentration of the nutritionally valuable monosaccharides increases approximately 1.6-fold after 3 days of irradiation with a solid state illuminator. This indicates that the nutritional quality of marjoram irradiated with solid state light is also not impaired.

These results demonstrate that reducing nutrient residues in leafy vegetables by short treatment with high-density photosynthetic photon fluxes produced by the proposed solid-state luminaire does not impair nutritional parameters (vitamin C and carbohydrate levels). Meanwhile, patent application JP2005245243 (2006) does not provide evidence that irradiation of vegetables does not impair the nutritional quality of the vegetables over a relatively long period (more than days before and / or at least one week after harvest).

FIG. 7 shows the change in nitrate, vitamin C and sugars in lettuce (GRAND RAPIDS) when irradiation was performed by changing the ambient conditions (lowering the ambient temperature). The lettuce was grown under a sodium lamp on a solid substrate. Cultivation was performed by irradiation with sodium lamp at a density of 100 pmol / m for 30 days²^^-1, for a photoperiod of 18/6 h and for a temperature of 21/17 ° C (day / night). After cultivation, the lettuce was transferred to a climatic chamber for irradiation at 4 ° C and a photoperiod of 24/0 h. The treatment was performed by irradiation with LEDs at a spectral peak at 640 nm at two photosynthetic flux density values ​​of 40 µmol / m^-2^^-1 and 900 pmolm ^ s^-1. The concentrations of nitrates, vitamin C and sugars were determined as described above.

Table 3 shows the numerical values ​​for nitrates, vitamin C and sugars.

table. Concentration of nitrates, vitamin C and sugars in lettuce immediately after cultivation and after irradiation with solid-state light at reduced temperature to 4 ° C (Fig. 7)

<td>Quality indicator</td><td>Immediately after cultivation by irradiation with a sodium lamp</td><td>Irradiation for 1 day, 40 µmol-m^_2s^-1</td><td>by irradiation for 1 day, 900 µmol-m^-2s^_1</td>

<td>Nitrates (mg-kg^-1)</td><td> 807±32</td><td> 586±15</td><td> 96±6</td>

<td>Vitamin C (mg-%)</td><td> 15,0±0,2</td><td>29.7 ± 0.1</td><td> 26,2±0,2</td>

<td>Fructose {mg-g^-1)</td><td> 0,59±0,03</td><td>1.36 ± 0.13</td><td>1.25 ± 0.04</td>

<td>Glucose (mg-g^l)</td><td> 0,55±0,02</td><td>l, 30 ± 0, ll</td><td>l, 29 ± 0, l 1</td>

<td>Sucrose (mg-g)</td><td> 0,14±0,01</td><td>l, 01 ± 0.05</td><td> 0,17±0,01</td>

<td>Maltose (mg-g^-1)</td><td> 0</td><td> 0,40±0,03</td><td> 0,26±0,01</td>

FIG. Tables 7 and 4 show that after changing the environmental conditions (lowering the temperature to 4 ° C), the nitrate concentration in the lettuce decreases noticeably (about 1.4 times) even after one day of irradiation, even at relatively moderate (40 pmol m 'V) density of photosynthetic flow . When a strong photosynthetic flux is used (900 pmol-m^_2s^-1), this decrease is 8.4 times after one day of irradiation. Accordingly, the levels of vitamin C and sugars increase. These results indicate that, under modified environmental conditions (e.g., lowering the ambient temperature), nitrate reduction can be achieved in a shorter treatment time or / and by irradiation with a lower photosynthetic flux than under the same conditions of cultivation.