Horticultural lighting equipment and lighting systems

Abstract

The present invention relates to horticultural lighting equipment and a lighting system. A horticultural lighting equipment comprises: a first LED group, the first LED group comprises at least one LED, the first LED group is configured to emit at least two emission peaks in the wavelength range of 300-800nm; a second LED group, the second LED group comprises at least one LED, the second LED group is configured to emit far-infrared light; and at least one electronic device control system, the at least one electronic device control system is used to independently control the intensity of the first LED group and the second LED group.

Description

[0001] This application is a divisional application. The invention title of the parent application is "Garden LED Lighting Equipment", the application number is 201710160504.3, and the application date is September 16, 2010. The parent application 201710160504.3 itself is a divisional application of the application with application number 201080038966.4. The second examination opinion notice of the parent application 201710160504.3 pointed out the unity defect. Technical Field

[0002] The present invention relates to the use of LEDs in horticultural lighting applications. In particular, the present invention relates to a lighting fixture for promoting plant growth, comprising at least one light emitting diode (LED) having a spectral characteristic including a peak in the wavelength range of 600 to 700 nm. The present invention also relates to a novel light emitting component, which is particularly suitable for promoting plant growth and comprises a light emitting compound semiconductor chip. Background Art

[0003] On Earth, the Sun is the main source of visible (i.e. light) and invisible electromagnetic radiation and is the main factor in sustaining life. The net daily average solar energy reaching Earth is about 28×10 ^ 23J (ie 265EBtu). This value is 5500 times the estimated annual world primary energy consumption of 479PBtu in 2007. The spectral distribution of solar radiation measurable on the earth's surface has a wide wavelength range between about 300nm and 1000nm.

[0004] But only 50% of the radiation that reaches the surface is photosynthetically active radiation (PAR). According to the CIE (Commission Internationale de L'Eclairage: International Commission on Luminous Illumination) recommendations, PAR includes the wavelength range between 400nm and 700nm of the electromagnetic spectrum. The law of photochemistry is usually expressed as plants harvesting radiation. The dual nature of radiation causes it to behave as an electromagnetic wave when propagating in space and as a particle (i.e. a photon or quantum of radiant energy) when interacting with matter. Photoreceptors are active elements present mainly on the leaves of plants, which are responsible for photon capture and for converting photon energy into chemical energy.

[0005] Due to the photochemical nature of photosynthesis, the photosynthesis rate, which represents the amount of O2 evolution or CO2 fixation per unit time, is related to the number of photons falling per unit area on the leaf surface per second. Therefore, the recommended amount of PAR is based on a quantum system and is expressed in terms of moles (mol) or micromoles (μmol) of photons. The recommended term for reporting and quantifying instantaneous measurements of PAR is photosynthetic photon flux density (PPFD), and it is usually expressed in μmoles / m 2 / s. This defines the number of moles of photons falling on a surface per unit area per unit time. The term photosynthetic photon flux (PPF) is also often used to express the same quantity.

[0006] Photoreceptors present in living organisms such as plants use captured radiation energy to mediate important biological processes. This mediation or interaction can occur in various ways. Photosynthesis, along with photoperiodism, phototropism, and photomorphogenesis, are four representative processes involving the interaction between radiation and plants. The following expression shows a simplified chemical equation for photosynthesis:

[0007] 6H2O+6CO2(+photon energy)→C6H 12 O6+6O2

[0008] As shown in the above equation, sugars such as glucose (C6H 12 O6) and oxygen (O2) are the main products of the photosynthesis process. They are synthesized and converted into chemical energy from carbon dioxide (CO2) and water (H2O) using photon energy, which is collected using specialized photoreceptors such as chlorophyll.

[0009] Radiant energy is also used as a major source of chemical energy through photosynthesis, which is important for the growth and development of plants. Of course, the input-output reactant balance of the equation also depends on the quantity (i.e., the number of photons) and quality (i.e., the energy of the photons) of the radiant energy and the quantity and quality of the resulting plant biomass. "Photoperiodism" refers to the ability that plants have to sense and measure the periodicity of radiation, phototropism refers to the growth movement of plants toward or away from radiation, and photomorphogenesis refers to the morphological changes in response to the quality and quantity of radiation.

[0010] Figure 1 Typical absorption spectra of the most common photosynthetic and photomorphogenic photoreceptors such as chlorophyll a, chlorophyll b and beta-carotene and the two interconvertible forms of phytochrome (Pfr and Pr) are shown in FIG.

[0011] Unlike photosynthesis, photomorphogenic responses can be achieved at very low light quantities. The different types of photosynthetic photoreceptors and photomorphogenic photoreceptors can be divided into at least three well-known photosynthetic systems: photosynthetic, phytochrome, and cryptochrome or blue / UV-A.

[0012] In photosynthesis photosynthetic system, the pigments present are chlorophyll and carotenoids. Chlorophyll is located in the thylakoids of chloroplasts in the mesophyll cells of plants. The amount or energy of radiation is the most important aspect, because the activity of these pigments is closely related to light harvest. The two most important absorption peaks of chlorophyll are in the red light range from 625nm to 675nm and in the blue light range from 425 to 475nm, respectively. In addition, other local peaks are also present in near ultraviolet (300-400nm) and far infrared ranges (700-800nm). Carotenoids such as lutein and carotene are located in the chromoplast pigment organelles on plant cells and mainly absorb the blue light range.

[0013] The phytochrome photosynthetic system includes two interconvertible forms of phytochrome: Pr and Pfr, which have sensitivity peaks at 660 nm in the red light range and 730 nm in the far infrared range, respectively. The photomorphogenic response mediated by phytochrome is usually related to the perception of light quality through the ratio (R / FR) of red light (R) to far infrared (FR). The importance of phytochrome can be assessed by the different physiological responses it is involved in, such as leaf expansion, proximity perception ability, shade avoidance, stem extension, seed germination, and flowering induction. Although the shade avoidance response is usually controlled by phytochrome through the perception of the R / FR ratio, blue light and PAR levels are also involved in the relevant adaptive morphological responses.

[0014] Blue light and UV-A (ultraviolet A) sensitive photoreceptors are found in the blue light receptor photosynthetic system. Blue light absorbing pigments include blue light receptors and phototropins. They are respectively involved in different tasks, such as monitoring the quality, quantity, direction and periodicity of light. Different groups of blue light and UV-A sensitive photoreceptors mediate important morphological responses, such as endogenous rhythms, organ orientation, stem extension and stomatal opening, germination, leaf expansion, root growth and phototropism. Phototropins regulate pigment content and the positioning of photosynthetic organs and organelles to optimize light harvesting and photoinhibition. Like exposure to far-infrared radiation, blue light also promotes flowering through the mediation of blue light receptor photoreceptors. Moreover, blue light sensitive photoreceptors (such as flavins and carotenoids) are also sensitive to near-ultraviolet radiation, where local sensitivity peaks can be found around 370nm. Blue light receptors are not only common to all plant species. Blue light receptors mediate various light responses, including the passage of circadian rhythms in flowering plants such as Arabidopsis. Although radiation with wavelengths below 300 nm is very harmful to the chemical bonds of molecules and DNA structures, plants also absorb radiation in this range. The quality of radiation in the PAR range is important to reduce the damaging effects of UV radiation. These photoreceptors are intensively studied and their role in controlling photosynthesis and growth is well known. However, there is evidence for the existence of other photoreceptors whose activity plays an important role in mediating important physiological responses in plants. Furthermore, the nature of the interactions and interdependencies between certain groups of photoreceptors is not well known to the public.

[0015] Photosynthesis is perhaps the oldest, most common and most important biochemical process in the world. It is common practice in northern countries, especially during winter, to use artificial light to replace or compensate for the low availability of sunlight for the production of vegetable and ornamental crops.

[0016] The era of artificial electrical lighting began with the development of the Edison bulb by Thomas Edison in 1879, commonly known in modern times as the incandescent lamp. Due to its thermal properties, incandescence is characterized by a large amount of far infrared radiation, which can reach about 60% of the total PAR. Although it has been developed for more than a century, the electrical efficiency of incandescent lamps, defined by the conversion efficiency between the electrical energy consumed (input) and the light energy emitted (output) in the visible spectrum, is still very low. It is usually about 10%. The life performance of incandescent light sources is also very low, with a typical life of no more than 1000 hours. The use of such lamps in plant growth applications is limited.

[0017] The growth of ornamental plants is one application where incandescent lamps can still be used. Floral initiation can be achieved for long-day responsive species using incandescent lamps and overnight exposure to low photon fluence rates. The large amounts of far-red radiation emitted are used to control photomorphogenic responses in a phytochrome-mediated process.

[0018] Fluorescent lamps are more widely used in plant growth applications than incandescent lamps. The electro-optical energy conversion of fluorescent lamps is more efficient than that of incandescent lamps. Tubular fluorescent lamps can reach electrical efficiency values ​​of typically about 20% to 30%, with greater than 90% of the emitted photons being in the PAR range and a typical lifetime of about 10,000 hours. However, specially designed long-life fluorescent lamps can reach lifetimes of up to 30,000 hours. In addition to excellent energy efficiency and lifetime, another advantage of using fluorescent lamps in plant growth is the amount of blue radiation emitted. Depending on the correlated color temperature (CCT) of the lamp, more than 10% of the total photon emission in the PAR range can be achieved. For this reason, fluorescent lamps are widely used in closed growth chambers and cavities to completely replace natural light radiation. The emitted blue radiation is necessary to achieve a balanced morphology of most crop plants through the mediation of the blue light receptor family of photoreceptors.

[0019] Metal halide lamps belong to the class of high intensity discharge lamps. The emission of visible radiation is based on the luminescent effect. Including metal halides in the manufacturing process optimizes the spectral quality of the emitted radiation to some extent. Metal halide lamps can be used in plant growth to completely replace sunlight or to appropriately compensate for it during the lower available time period. The high PAR output of each lamp, the relatively high percentage of blue light radiation of about 20%, and the electrical efficiency of about 25% make metal halide lamps a choice for year-round crop cultivation. The operating time of metal halide lamps is generally 5,000 to 6,000 hours. High pressure sodium (HPS) lamps have become the preferred light source for year-round crop production in greenhouses. The main reasons are high radiation emission, low cost, long life, high PAR emission, and high electrical efficiency. These factors have made the use of high pressure sodium lamps as a supplementary light source to assist vegetable growth in a cost-effective manner during the winter in northern latitudes.

[0020] However, the spectral quality of HPS lamps is not optimal for promoting photosynthesis and photomorphogenesis, thus resulting in excessive growth of leaves and stems. This is attributed to the unbalanced spectral emission associated with the absorption peaks of important photosynthetic pigments such as chlorophyll a, chlorophyll b and beta-carotene. Compared with other light sources, the low R / FR ratio and low blue light emission cause excessive stem growth for most crops grown under HPS lighting. The electrical efficiency of high pressure sodium lamps is usually in the range of 30% and 40%, which makes it the most energy efficient light source used in contemporary plant growth. About 40% of the input energy is converted into photons in the PAR region and almost 25% to 30% is converted into far infrared and infrared light. The operating time of high pressure sodium lamps is in the range of about 10,000 to 24,000 hours.

[0021] The low availability of daylight in northern latitudes and the demand of users for high-quality horticultural products at low cost all year round have led to the need for new lighting and biotechnologies. And if the available daylight reached 20 to 24 hours per day, the global yield could be significantly increased. Therefore, solutions are needed to reduce the production costs of crops, increase yields and quality. Lighting is only one aspect that can be optimized. But its importance cannot be underestimated. The rising electricity prices and the need to reduce CO2 emissions are other reasons for the efficient use of energy. For year-round crop production in greenhouses, electricity costs can reach about 30% of the indirect costs for some crops.

[0022] While existing light sources typically used for plant growth have electrical efficiencies of about 40%, the overall system efficiency can be significantly lower (i.e., including losses in drivers, reflectors, and optics). The spectral quality of the radiation is critical to the healthy growth of crops. Conventional light sources cannot be spectrally controlled during their application without the inefficiency and limited application of other filters. Also, control of the amount of radiation is limited, reducing the possibility of versatile lighting methods such as pulsed operation.

[0023] Therefore, for reasons related to the above, light emitting diodes and related solid-state lighting (SSL) are beginning to be seen as potentially viable and promising tools for use in horticultural lighting. The internal quantum efficiency of an LED is a measure of the percentage of photons generated by each electron injected into the active region. In fact, the best AlInGaP red and AlInGaN green and blue HB-LEDs can have internal quantum efficiencies greater than 50%, but extracting all the generated light from the semiconductor device and lighting fixtures remains a challenge.

[0024] In horticultural lighting, the main practical advantages of LED-based light sources over conventional light sources are the directionality and complete controllability of the emitted radiation. LEDs do not necessarily require reflectors because they are inherently halfisotropic emitters. Using LEDs as directional emitters avoids most of the losses associated with optics. Moreover, the narrow spectral bandwidth characteristics of colored LEDs are another important advantage compared to conventional broadband light sources. The main advantage of using LEDs as a source of photosynthetic radiation arises from the possibility of selecting the peak wavelength emission that most closely matches the absorption peak of the selected photoreceptor. In fact, this possibility brings other advantages. The efficient use of the radiation energy by the photoreceptors in the mediation of the physiological response of the plant is one of the advantages. Another advantage is the controllability of the response by fully controlling the radiation intensity.

[0025] The above advantages extend further to the luminaire level. The inventors are aware of luminaires with blue LEDs and red LEDs. The radiation spectrum of current color AlInGaN LEDs is available from the UV to the green region of the visible spectrum. Those devices can emit in the blue and UV-A regions, which are exactly where the absorption peaks of blue light receptors and carotenoids are located.

[0026] The red isomeric forms of chlorophyll a and phytochrome (Pr) have strong absorption peaks around 660nm. AlGaAs LEDs emit in the same region, but they are expensive devices compared to phosphide or nitride-based LEDs, partly due to low market demand and old manufacturing technology. AlGaAs LEDs can also be used to control the far-infrared form of phytochrome (Pfr), which has a distinct absorption peak at 730nm.

[0027] AlInGaP LEDs are based on well-established material technology and have relatively high optical and electrical performance. Typically, the characteristic spectral emission region of AlInGaP red LEDs covers the region around 640nm, where chlorophyll b has an absorption peak. Therefore, AlInGaP LEDs can also be used to enhance photosynthesis.

[0028] New commercial high-brightness LEDs are not suitable for greenhouse cultivation because their main emission peak is in the green wavelength range of 500nm to 600nm, and therefore cannot respond to the photosynthesis process. However, according to technical principles, photosynthesis-responsive LED light can be constructed by combining different types of semiconductor LEDs such as AlInGaP and AlInGaN for red and blue light.

[0029] There are also many problems associated with the combination of individual color LEDs. As a result, different types of semiconductor devices will age at different rates, and for this reason the ratio of red to blue light will vary over time, further leading to anomalies in the plant growth process. The second major factor is that individual single color LEDs have a relatively narrow photoreproduction range, typically less than 25nm, which is insufficient to provide good photosynthesis efficiency without using a large number of different color and individual LEDs, thus resulting in high cost of implementation.

[0030] From EP 2056364 A1 and US 2009 / 0231832 it is known that an increased number of colors can be produced from LEDs with wavelength conversion materials such as phosphors, thereby re-emitting light of different colors. According to US 2009 / 0231832, replicating sunlight of different colors can be used to treat depression or seasonal diseases. The above documents are incorporated herein by reference.

[0031] Even if these lights are used for horticultural lighting, they still have many disadvantages, for example for the simple reason that the spectrum of sunlight is not suitable for plant growth. The lamp of US 2009 / 0231832 is intended to replicate sunlight, including many unnecessary wavelengths that cannot be effectively used for plant growth. For example, light in the 500-600nm (green light) band cannot be used by plants because green plants reflect these wavelengths. This leads to wasted energy in horticultural applications.

[0032] Furthermore, prior art lights also ignore essential wavelength ranges that are very suitable for plant growth. For example, these lights cannot reach the far infrared range of 700nm-800nm, which is important for plant cultivation. Summary of the invention

[0033] The object of the present invention is to eliminate at least some of the problems associated with the prior art and to provide a new way of promoting plant growth using LEDs.

[0034] A first object of the present invention is to provide an LED device based on a single light emitting source to which the photosynthesis process responds well.

[0035] A second object of the present invention is to provide a lighting fixture for greenhouse cultivation based on photosynthetic photon flux (PPF) optimized LEDs.

[0036] A third object of the present invention is to achieve an LED device having at least two emission peaks in the wavelength range of 300 to 800 nm and at least one emission peak having a half-width (FWHM) of at least 50 nm or more.

[0037] A fourth object of the present invention is to provide an LED-based greenhouse planting lighting fixture, wherein during 10,000 hours of operation, the intensity ratio of the two emission frequencies of 300-500nm and 600-800nm ​​decreases by less than 20%.

[0038] A fifth object of the present invention is to provide a technical solution having a better PPF value per watt (i.e. PPF to wattage of power used) than that achieved by conventional high pressure sodium lamps commonly used in greenhouse cultivation, and thereby providing an energy efficient light source for greenhouse cultivation processes and the artificial lighting used therein.

[0039] A sixth object of the present invention is to provide a single light emitting source in which the emission at a frequency of 300-500 nm is produced by a semiconductor LED chip and the emission at a frequency of 600-800 nm is produced by wavelength up-conversion using a portion of the radiated power of the LED chip. The inventors have found that, for example, cucumber and lettuce plants can achieve greater length and / or mass when illuminated with the horticultural light of the present invention comprising far infrared light (700-800 nm).

[0040] A seventh object of the present invention is to provide a single light emitting source, wherein the emission at a frequency of 300-500nm is generated by a semiconductor LED chip, and the emission at a frequency of 600-800nm ​​is generated by wavelength up-conversion of part of the radiated power of the LED chip. The wavelength up-conversion to produce 600-800nm ​​radiation is achieved by using one or more wavelength up-conversion materials adjacent to the LED emission source.

[0041] In the present application, "up-conversion" is interpreted as changing the wavelength of incident absorbed light into emitted light of a longer wavelength.

[0042] An eighth object of the present invention is to provide partial or full wavelength up-conversion of radiation from a semiconductor LED chip having an emission in the range of 300-500nm, 600-800nm ​​or both of the above frequency ranges. The wavelength up-conversion is achieved by using organic, inorganic or a combination of both types of materials.

[0043] A ninth object of the present invention is to provide wavelength up-conversion using nano-sized particulate materials for up-conversion.

[0044] A tenth object of the present invention is to provide wavelength up-conversion using molecular like materials for up-conversion.

[0045] An eleventh object of the present invention is to provide wavelength up-conversion using polymer materials, wherein the up-conversion material is covalently bonded to a polymer matrix to provide wavelength up-conversion.

[0046] The twelfth object of the present invention is to provide an LED-based lighting device in which the spectral band of 500-600nm is suppressed. There will be almost no emission or no emission in this suppressed band, or in any case there will be very little emission compared to the adjacent spectral bands of 400-500nm, 600-700nm. According to the present invention, the above-mentioned suppression effect can be achieved by not having any emission or only having a small amount of primary emission in the 400-500nm band, and by ensuring that any up-conversion results in a wavelength shift to a wavelength shift exceeding 600nm. It is well known that green plants cannot utilize green light (500-600nm) radiation and radiation in adjacent bands because this radiation is simply reflected from the plant instead of being absorbed for photosynthetic conversion.

[0047] A thirteenth object of the present invention is to provide an LED-based lighting fixture that maximizes the anabolic growth of plants by providing the required far infrared light while minimizing green light which is energy-wasting radiation from a plant cultivation perspective. In one aspect of the present invention, the above object is achieved by a blue light LED having a wavelength up-conversion device that up-converts a portion of the emitted blue light (300-500) nm into a broad red spectral component (600-800 nm) having a far infrared component while eliminating and / or minimizing the green light component (500-600 nm).

[0048] The present invention provides a light emitting diode suitable for greenhouse planting and related lighting equipment. According to the present invention, the light emitting diode has a specific emission frequency mode, that is, it has at least two spectral characteristics, one emission peak has a half-height width of at least 50nm or more and has a peak wavelength in the range of 600 to 700nm, and the second spectral characteristic has a peak wavelength below 500nm. The emission peak of the LED is well matched with the plant photosynthesis response spectrum and is therefore particularly suitable for efficient artificial lighting.

[0049] The light-emitting component suitable for promoting plant growth comprises a light-emitting compound semiconductor chip and a light wavelength up-conversion phosphor deposited directly adjacent to the LED chip. Such a component can emit two characteristic light emission peaks.

[0050] More specifically, the lighting fixture according to the invention is characterized by what is stated in the characterizing parts of claims 1 and / or 2 .

[0051] According to the present invention, a lighting fixture for promoting plant growth includes at least one light emitting diode (LED), the light emitting diode including:

[0052] a) a first spectral characteristic comprising a peak in the wavelength range of 600 to 700 nm and arranged to exhibit a half-width of at least 50 nm or more; and

[0053] b) A second spectral characteristic having a half-width at maximum of 50 nm and arranged to exhibit a peak wavelength in the range of 440 to 500 nm.

[0054] A horticultural lighting fixture according to the present invention comprises at least one light emitting diode (LED), the light emitting diode comprising:

[0055] a) a first spectral characteristic comprising a peak in the wavelength range of 600 to 700 nm and arranged to exhibit a half-width at least 50 nm or more;

[0056] b) a second spectral characteristic having a half-width of a maximum value of 50 nm and arranged to exhibit a peak wavelength in the range of 440 to 500 nm, and

[0057] c) Utilizing wavelength up-conversion of all or part of the radiant power of the LED chip to produce all or part of the emission at a frequency of 600-800nm.

[0058] A horticultural lighting fixture according to the present invention comprises at least one light emitting diode (LED), the light emitting diode comprising:

[0059] a) a first spectral characteristic comprising a peak in the wavelength range of 600 to 700 nm and arranged to exhibit a half-width at least 50 nm or more;

[0060] b) a second spectral characteristic having a half-width of a maximum value of 50 nm and arranged to exhibit a peak wavelength in the range of 440 to 500 nm, and

[0061] c) arranging at least part or all of the emission at a wavelength of 500-600 nm to be minimised and / or eliminated and / or reduced to below the intensity in the 400-500 nm band and below the intensity in the 600-700 nm band.

[0062] The lighting fixture for promoting plant growth according to the present invention comprises a light-emitting UV LED, which light-emitting UV LED optionally has an external emission characteristic, and the LED is arranged to show

[0063] a) having a first phosphorescence spectral characteristic with a peak wavelength in the range of 350 to 550 nm;

[0064] b) a second selectable phosphorescence spectral characteristic having a peak wavelength in the range of 600 to 800 nm;

[0065] c) a third selectable phosphorescence spectral characteristic having a peak wavelength freely adjustable between 350 and 800 nm;

[0066] d) The phosphorescent emission intensities of the first, optional second and optional third spectral characteristics are adjustable in any ratio.

[0067] The lighting component is characterized by what is stated in the characterizing part of claim 16 and / or 17 .

[0068] The light-emitting component for promoting plant growth according to the present invention comprises:

[0069] Light-emitting compound semiconductor chip; and

[0070] a light wavelength up-conversion phosphor deposited directly adjacent to the LED chip;

[0071] The component can emit two characteristic luminescence peaks.

[0072] The light-emitting component of the horticultural lighting according to the present invention comprises:

[0073] Light-emitting compound semiconductor chip; and

[0074] a light wavelength up-conversion phosphor deposited directly adjacent to the LED chip;

[0075] The component can emit two characteristic luminescence peaks, and utilizes all or part of the wavelength up-conversion of the LED chip radiation power to generate all or part of the emission at a frequency of 600-800nm.

[0076] The light-emitting component of the horticultural lighting according to the present invention comprises:

[0077] Light-emitting compound semiconductor chip; and

[0078] a light wavelength up-conversion phosphor deposited directly adjacent to the LED chip;

[0079] The component is capable of emitting two characteristic luminescence peaks and at least a portion or all of the emission at a wavelength of 500-600nm is arranged to be minimized and / or eliminated and / or reduced to below the intensity in the 400-500nm band and below the intensity in the 600-700nm band.

[0080] The best mode of the invention is believed to include a plurality of LEDs in the wavelength range of 380-850 nm arranged to have an emission spectrum arranged to be consistent with the photosynthetic response of plants to be grown by illumination by said LEDs. The best mode is characterized by wavelength up-conversion of the emission of the blue LEDs by a phosphor. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 The relative absorption spectra of the most common photosynthetic and photomorphogenic photoreceptors in green plants are shown;

[0082] Figure 2 shows the emission peak of the first single light emitting source LED device according to the present invention;

[0083] Figure 3 shows the emission peak of the second single light emitting source LED device according to the present invention;

[0084] Figure 4 shows the emission peak of the third single light emitting source LED device according to the present invention;

[0085] Figure 5 shows the emission peak of a fourth single light emitting source LED device according to the present invention; and

[0086] Figures 6a to 6c It is a schematic diagram showing various process steps of a method for manufacturing an improved LED device according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0087] As described above, the present invention generally relates to a single light source LED device having optimal properties for use as a greenhouse planting light source. Specifically, the method constructs a light source having optimal properties and can be flexibly used to match the photosynthesis frequency in plant planting. By utilizing the above method, the light source can be designed to achieve excellent PPF and PPF per watt efficiency and performance and have very low power consumption and very long operating life compared to the prior art.

[0088] In particular, a single light source LED device provides at least two emission peaks in the wavelength range of 300-800 nm and at least one of the emission peaks has a half-maximum width (FWHM) of at least 50 nm or greater. The emission peaks and relative intensities are selected to match the photosynthesis frequency of the plant. Furthermore, the required PPF amount for the light source is optimized to meet the requirements of the plant.

[0089] The emission of 300-500nm frequency is generated by a semiconductor LED chip, and the emission of 400-800nm ​​frequency is generated by all or part of the wavelength up-conversion of the LED chip radiation power. The partial wavelength up-conversion can be selected so that it is in the range of 5-95%, preferably 35-65% of the semiconductor LED chip radiation. The wavelength up-conversion to generate 400-800nm ​​radiation can be achieved by using one or more up-conversion materials adjacent to the LED emission source. The wavelength up-conversion is achieved by using organic, inorganic or a combination of the above types of materials. These materials can be special (nanoscale or other size particles), molecular or polymer materials. Moreover, the above materials can have a structural arrangement that causes the wavelength up-conversion of the emission source.

[0090] According to one specific embodiment, a lighting fixture for promoting plant growth includes UV LEDs, optionally with exoluminescent emission characteristics. LEDs typically exhibit:

[0091] a) a first phosphorescence spectral characteristic having a peak wavelength in the range of 350 to 550 nm;

[0092] b) a second selectable phosphorescence spectral characteristic having a peak wavelength in the range of 600 to 800 nm; and

[0093] c) A third selectable phosphorescence spectral characteristic with a freely adjustable peak wavelength between 350 and 800 nm.

[0094] In the present application, the above-mentioned "adjustable" peak wavelength is interpreted as the peak wavelength being adjustable during the assembly of the lighting fixture in the factory, and / or also being "adjustable" for an adjustable dial in the lighting fixture for on-site peak wavelength adjustment. In addition, the peak wavelength of the LED can also be adjusted during the manufacturing process of the LED according to the present invention, and "adjustable" should be interpreted as also including being adjustable during the manufacturing process of the LED. All of the above-mentioned embodiments of adjustable peak wavelength or any other adjustable light source or variable LED fall within the scope of the present patent application.

[0095] Preferably, the phosphorescent emission intensities of the first, optional second and optional third spectral characteristics are adjustable in arbitrary proportions.

[0096] Figures 2 to 5 Some examples of emission peaks for a single light emitting source LED device are shown.

[0097] exist Figure 2In the embodiment, the semiconductor LED chip emission frequency produces a peak at a wavelength of 457nm with an emission peak half-width (FWHM) of 25nm. In this case, wavelength up-conversion can be achieved using two up-conversion materials. The above two wavelength up-conversion materials have separate emission peaks at 660nm and 604nm. Figure 2 The two wavelength up-conversion materials are shown to produce a combined emission peak at 651 nm with an emission peak half-width of 101 nm. In this case, approximately 40% (calculated from the peak intensity) of the emission of the semiconductor LED chip is up-converted to 651 nm emission by the two separate up-conversion materials.

[0098] exist Figure 3 In the embodiment, the semiconductor LED chip emission frequency produces a peak at 470nm with an emission peak half-width (FWHM) of 30nm. In this case, wavelength up-conversion can be achieved using two up-conversion materials. The above two wavelength up-conversion materials have separate emission peaks at 660nm and 604nm. Figure 2 The combined emission peak produced by these two wavelength up-conversion materials at a wavelength of 660 nm is shown with an emission peak FWHM of 105 nm. In this case, approximately 60% (calculated from the peak intensity) of the emission of the semiconductor LED chip is up-converted to 660 nm emission by the two separate "up-conversion" materials.

[0099] exist Figure 4 In the embodiment, the semiconductor LED chip emission frequency produces a peak at 452nm with a 25nm emission peak half-width (FWHM) (not shown in the figure). In this case, wavelength up-conversion can be achieved using an up-conversion material. Figure 3 The wavelength up-conversion material produces an emission peak at a wavelength of 658 nm with an emission peak FWHM of 80 nm. In this case, approximately 100% (calculated from the peak intensity) of the emission of the semiconductor LED chip is up-converted to 658 nm emission by the up-conversion material. This can be seen from Figure 4 It can be seen that there is no emission at 452nm in the LED device.

[0100] exist Figure 5 In the embodiment, the emission frequency of the semiconductor LED chip produces a peak at 452 nm with an emission peak half-width (FWHM) of 25 nm. In this case, wavelength up-conversion can be achieved using an up-conversion material. Figure 5 The wavelength up-conversion material is shown to produce an emission peak at a wavelength of 602 nm with an emission peak FWHM of 78 nm. In this case, approximately 95% (calculated from the peak intensity) of the emission of the semiconductor LED chip is up-converted to 602 nm emission by the wavelength up-conversion material.

[0101] For the above spectrum, the device can be constructed as described in detail below. The semiconductor LED chip emission frequency should be selected in a way that is suitable for exciting the phosphor molecules used in the device. The emission from the LED chip can be between 400nm and 470nm.

[0102] The phosphor molecule or molecules used should be selected in such a way that the desired emission spectrum from the LED is achieved.

[0103] The following will explain the process of achieving the desired spectrum using two phosphor materials (wavelength up-conversion materials) in LED devices (refer to Figures 6a to 6c ).

[0104] Phosphor A and phosphor B are mixed in a predetermined ratio to achieve the desired phosphor emission spectrum from the LED device (see Figure 6a ). The ratio of phosphors can be, for example, 99:1 (A:B) to 1:99. The above-mentioned phosphor A+B mixture is mixed into a material C (for example, a polymer) at a predetermined concentration to form a "sealing material". The concentration of phosphors in material C can be, for example, 99:1 (phosphor mixture: material C) to 1:99. The above-mentioned material C+phosphor (A and B) mixture is then deposited directly adjacent to the LED chip ( Figure 6b and 6c ). Here, "adjacent" means deposited directly on the surface of the LED chip or separated by other optical materials. The concentration of the phosphor mixture in material C determines the amount of wavelength up-conversion of the semiconductor LED chip emission frequency, that is, how much of the "original" LED chip emission frequency is present in the final LED device emission and how much of the LED device is converted to phosphor emission.

[0105] Depending on the concentration of the phosphor, the thickness of the sealing material (in which the phosphor is mixed) generally ranges from 0.1 μm to 20 mm, in particular from 1 μm to 10 mm, preferably from 5 μm to 10 mm, for example about 10 μm to 5 mm.

[0106] Typical concentrations of phosphor (calculated based on the total weight of the encapsulant) are about 0.1 to 20%, preferably about 1 to 10%.

[0107] The wavelength up-conversion may be 100%, meaning that only the phosphor emission is observed from the LED device, or the wavelength up-conversion may be less than 100%, meaning that some of the LED chip emission is emitted from the LED device.

[0108] In summary, by adjusting the phosphor ratio A:B, the desired phosphor emission spectrum from the LED device can be adjusted, and by adjusting the concentration of the phosphor in material C, the desired LED chip emission amount / total amount for the LED device can be adjusted.

[0109] The amount (physical thickness) of material C (with a certain phosphor concentration) on top of the LED chip also affects the amount of LED chip emission that the LED device transmits. The thicker the layer of material C on top of the LED chip, the lower the transmission.

[0110] Material C may be, for example, a solvent, an inorganic or organic polymer, a silicon polymer, a siloxane polymer or other polymer that can be mixed into the phosphor. Material C may have one or more components that need to be mixed in before use with the phosphor. Material C may be a thermosetting or UV curable material.

[0111] The mixture of phosphor and solvent material C (solid or liquid) may be translucent or transparent, preferably transparent, to allow light emitted from the LED to pass through.

[0112] In one embodiment, for example, Ba co-doped with europium and cerium is particularly preferred. _x Sr _y ZnS _3 Phosphors and / or cerium-doped lanthanide oxysulfides produce far-infrared radiation (700-800 nm). These phosphors and sulfide types have a maximum emission peak in the 650-700 nm wavelength region and also exhibit a wide half-width (50-200 nm), and therefore can also produce light emission at higher wavelengths, i.e., in the wavelength range above 700 nm.

[0113] In addition or as an alternative to the use of phosphors or other similar materials, wavelength up-conversion can also be achieved by means of at least one semiconductor quantum dot or the like arranged in the vicinity of the LED.

[0114] Examples

[0115] Based on having Figure 3 The LED lighting fixture was constructed using a single LED device with the same output spectrum as shown in Figure 1 for the purpose of comparative experiments. The lighting fixture consists of 60 individual LED units, which have a power consumption of 69W, which includes the power consumption of the AC / DC constant current driver.

[0116] The comparison devices were a commercial HPS (High Pressure Sodium) lamp greenhouse lighting fixture with a total power consumption of 420 W and a commercial LED greenhouse LED fixture. The commercial LED fixture was based on separate blue and red LED devices with a total power consumption of 24 W.

[0117] The LED lighting fixtures according to the present invention were tested against the commercial LED devices described above using the following PPF measurement procedure and arrangement.

[0118] PAR irradiance (irradiance value between 400nm and 700nm) and PPF value are calculated by measuring the lighting fixture spectrum from 300nm to 800nm ​​and the absolute irradiance value in the wavelength band from 385nm to 715nm. The spectrum of each lamp is measured at a certain distance with the help of an ILT700A spectroradiometer. The absolute irradiance value is measured at certain distances with the help of a precision pyranometer and then used to calculate the absolute spectrum at these distances. These absolute spectra are used to calculate the calculation of PAR and PPF. PAR irradiance (W / m 2 ). This is done by first converting the irradiance value of each spectral “channel” from W / m 2 The PPF value is calculated by transforming to microeinsteins and then integrating the spectrum over the desired wavelength band.

[0119] The results of the comparison of the above two commercial greenhouse light fixtures and the LED fixture according to the present invention are shown in the table below. The results were also normalized to the commercial HPS lighting fixture.

[0120]

[0121] As shown in the above test results, the LED lighting fixture according to the present invention provides 3.27 times the PPF efficiency compared to HPS and 1.18 times the PPF efficiency compared to commercial LED greenhouse fixtures based on separate blue and red LED devices. Of course, in many embodiments of the present invention, all LEDs or lighting fixtures are arranged to be used as greenhouse light sources, especially in greenhouses for plant cultivation.

[0122] The above examples have described embodiments with one light emitting diode (LED) having the spectral characteristics shown. Of course, the lighting fixture of the present invention may include a plurality of LEDs, at least some of which (i.e. 10% or more) or preferably a majority of which (greater than 50%) have the properties and characteristics shown. Thus, fixtures may be obtained that include a combination of conventional LEDs and the LEDs described in the present invention. There is no particular upper limit to the number of LEDs. Thus, the lighting fixture of the present invention may have approximately 1 to 10,000 LEDs, typically 1 to 1,000 LEDs, and in particular 1 to 100 LEDs.

[0123] According to the present invention, LEDs with different peak emissions can be included in one lamp and controlled to provide the desired spectral emission to achieve a certain growth result or physiological response. In this way, the lighting system can allow for versatile control of lighting intensity and spectrum. Ultimately, the control of other abiotic factors such as CO2 concentration, temperature, daylight availability, and humidity can be integrated into the same control system as lighting to optimize crop productivity and overall greenhouse management.

[0124] References:

[0125] EP 2056364 Al, Satou et al.

[0126] US 2009 / 0231832, Zukauskas et al.

Claims

1. A horticultural lighting device comprising: -Light emitting diode LED chips; as well as - a light wavelength up-conversion phosphor, which is deposited directly adjacent to the LED chip; The horticultural lighting fixture is capable of emitting two characteristic luminescence peaks, and utilizes wavelength up-conversion of all or part of the radiant power of the LED chip to produce all or part of the emission at a frequency of 600-800nm; wherein at least part or all of the emission at a wavelength of 500-600nm is arranged to be minimized and / or eliminated and / or reduced to an intensity below that in the 400-500nm band and below that in the 600-700nm band; wherein the LED chip has a peak emission range of 440 to 500 nm; wherein the wavelength up-conversion phosphor is arranged to convert part of the light emission energy emitted by the LED chip into a long wavelength of 600 to 700 nm; The two characteristic luminescence peaks are respectively at 440nm-500nm and 600-700nm. 2 . The horticultural lighting fixture of claim 1 , wherein the light wavelength up-conversion phosphor is formed by mixing at least two phosphors with each other.

3. The horticultural lighting fixture of claim 1, wherein the light wavelength up-conversion phosphor is deposited directly on the surface of the LED chip or separated by other optical materials.

4. The horticultural lighting fixture of claim 1, wherein the two characteristic emission peaks have the following spectral characteristics: one has a half-width of at least 50 nm, and the other has a half-width of a maximum value of 50 nm, and the two are in different wavelength ranges.

5. A horticultural lighting fixture according to claim 1, wherein emission at a frequency of 300-500nm is arranged to be produced by the LED chip, and emission at a frequency of 400-800nm ​​is arranged to be produced by wavelength up-conversion of all or part of the radiated power of the LED chip provided by the optical wavelength up-conversion phosphor.

6. The horticultural lighting fixture of claim 1, wherein the partial wavelength up-conversion is 5-95% of the radiation of the LED chip.

7. The horticultural lighting fixture of claim 2, wherein the light wavelength up-conversion phosphor is formed by mixing at least two phosphors with each other and further mixing into a third component selected from the group consisting of solvents, inorganic or organic polymers, silicon polymers, siloxane polymers, and other polymers.

8. The horticultural lighting fixture of claim 6, wherein the partial wavelength up-conversion is 35-65% of the radiation of the LED chip.

Images