LED light source for plant illumination, preparation method and lamp

Abstract

The invention discloses an LED light source for plant illumination, a preparation method and a lamp. The LED light source for plant illumination comprises a support, a step is arranged on the surface of the support, a transparent sealing cover covers the upper surface of the step, and a containing cavity is formed between the transparent sealing cover and the support. The blue light LED chip and the red light LED chip are connected in series or in parallel and are arranged in the accommodating cavity; the surface of the blue light LED chip is coated with a first fluorescent glue layer, the first fluorescent glue layer comprises a first fluorescent powder group and a first transparent glue which are fully and uniformly mixed, and the first fluorescent powder group emits white light under the excitation of blue light generated by the blue light LED chip; the first fluorescent glue layer and the red light LED chip are coated with a second fluorescent glue layer, the second fluorescent glue layer comprises a second fluorescent powder group and a second transparent glue which are fully and uniformly mixed, and the second fluorescent powder group emits near-infrared light under the excitation of the blue light LED chip and the red light LED chip.

Description

Technical Field

[0001] The present invention relates to the field of lighting technology, and more specifically, to an LED light source for plant lighting, a preparation method thereof, and a lamp having the LED light source. Background Art

[0002] Light environment is one of the important physical environmental factors for plant growth and development. The effect of light on plants is mainly reflected in two aspects: on the one hand, light provides the necessary radiation energy for plant photosynthesis, which is the basis for plants to obtain energy and grow; on the other hand, light, as a signal molecule, regulates many physiological processes in the entire life cycle of plants, including growth, flowering, and fruiting. In the growth process of plants, suitable spectral components are essential for promoting photosynthesis and improving growth efficiency. In order to meet the diversified needs of plants for light at different growth stages, a comprehensive LED plant lighting solution often needs to integrate blue light, red light, and appropriate amounts of white light and infrared light. Blue light of 400-450nm is conducive to the formation of anthocyanins and resistance to the growth of branches and leaves; red light of 650-660nm promotes the overall growth of plants, especially in the flowering and fruiting periods, increases the growth rate, increases the number of fruits, and reduces the incidence of deformed fruits. Near-infrared light around 730nm has a positive effect on plant growth, such as regulating plant growth cycles, promoting seed germination, and regulating seedling morphology.

[0003] The light source of the LED plant growth lamp commonly used in the market is LED patch lamp beads, each of which contains a chip to excite the phosphor to obtain a single light source. For example, a white LED light source is obtained by using a 450nm blue LED chip to excite the phosphor, a 660nm red LED chip directly emits red light, and a 730nm chip directly emits near-infrared light. The light source formed by the mixture of multiple light sources has the disadvantages of uneven light emission and serious scattering, resulting in uneven irradiation, uneven light reception for plants, and uneven growth surface. At the same time, the light is greatly scattered, causing energy waste. In addition, due to the limitations of chip materials and technical level, the potential for improving the quantum efficiency of the 730nm chip is limited, and its price is 10 to 20 times that of the 450nm chip, which increases the pressure of preparation costs. Summary of the invention

[0004] The present invention proposes an LED light source for plant lighting, which aims to solve the problem that the plant growth lamp in the prior art has poor light uniformity and is not conducive to use. In addition, while solving the problem of the uniformity of the current plant light source, the photosynthetic light quantum efficiency of the LED light source is greatly improved.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] An LED light source for plant lighting comprises a bracket, a surface of which is provided with steps, an upper surface of the steps is covered with a transparent cover, and a receiving cavity is formed between the transparent cover and the bracket; a blue light LED chip and a red light LED chip connected in series or in parallel are arranged in the receiving cavity; a first fluorescent glue layer is coated on the surface of the blue light LED chip, the first fluorescent glue layer comprises a first fluorescent powder group and a first transparent glue that are fully and evenly mixed, wherein the first fluorescent powder group emits white light under the excitation of the blue light generated by the blue light LED chip; a second fluorescent glue layer is coated on the first fluorescent glue layer and the red light LED chip, the second fluorescent glue layer comprises a second fluorescent powder group and a second transparent glue that are fully and evenly mixed, wherein the second fluorescent powder group emits near-infrared light under the excitation of the blue light and red light LED chips.

[0007] Preferably, the first phosphor group includes green phosphors with emission peak wavelengths of 500-550 nm and red phosphors with emission peak wavelengths of 600-660 nm; the second phosphor group includes near-infrared phosphors with emission peak wavelengths of 700-750 nm.

[0008] Preferably, the first phosphor group includes green phosphor with an emission peak wavelength of 530-540 nm and red phosphor with an emission peak wavelength of 620-630 nm; the second phosphor group includes near-infrared phosphor with an emission peak wavelength of 710-730 nm.

[0009] Preferably, the emission peak wavelength of the blue LED chip is 430-460 nm, and the emission peak wavelength of the red LED chip is 620-660 nm.

[0010] Preferably, the emission wavelength peak wavelength of the blue LED chip is a combination of 435-440 nm, 445-450 nm, and 455-460 nm, and the emission wavelength of the red LED chip is 655-660 nm.

[0011] Preferably, the blue light LED chip has a radiation intensity ratio of 1: (0.95-0.99): (0.90-0.94) at peak wavelengths of 435-440 nm, 445-450 nm, and 455-460 nm.

[0012] Preferably, the light radiation power ratio of the blue LED chip to the red LED chip is 1:(3-9).

[0013] Preferably, the first phosphor group accounts for 15-50% of the first fluorescent glue layer, and the first transparent glue accounts for 50-85%; and the lower the color temperature, the higher the proportion of the first phosphor group; the ratio of the second phosphor group to the second transparent glue in the second fluorescent glue layer is 1:(10-20).

[0014] Preferably, the transparent cover is a silicone lens, and the ratio of the refractive index of the silicone lens to the refractive index of the second transparent adhesive is (1.01-1.03):1.

[0015] The present invention also proposes a method for preparing the above-mentioned LED light source for plant lighting, comprising the following steps: step one, encapsulating a blue light LED chip and a red light LED chip connected in series or in parallel on the upper surface of a bracket; step two, preparing a first fluorescent glue layer, and fully mixing a first fluorescent powder group with a first transparent glue; applying the first fluorescent glue on the blue light LED chip; step three, preparing a second fluorescent glue layer, and fully mixing a second fluorescent powder group with a second transparent glue; uniformly applying the second fluorescent glue below the step of the bracket to cover the first fluorescent glue layer and above the red light LED chip; step four, spot coating or molding on the upper surface of the step of the bracket to form a transparent cover.

[0016] In addition, the present invention also provides a plant lighting lamp, which includes the above-mentioned LED light source for plant lighting.

[0017] Due to the adoption of the above technical solution, the advantages of the present invention are:

[0018] 1. By coupling the blue LED chip and the red LED chip with phosphor to form the same LED light source, the uniform distribution of spectral components is achieved, avoiding the problem of uneven distribution of spectral components in traditional plant lighting fixtures.

[0019] 2. The design of using infrared phosphor to replace infrared chips reduces the production cost of lamps, further enriches the spectral composition, and improves the overall efficiency of plant lighting lamps.

[0020] 3. The LED plant lighting source of the present invention greatly improves the photosynthetic quantum efficiency of the light source by optimizing the packaging structure, optimizing the chip wavelength and light power, and optimizing the phosphor ratio while ensuring spectral uniformity.

[0021] Therefore, the LED light source of the present invention has very broad application prospects in plant lighting. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The figure shows a schematic diagram of the structure of an LED light source for plant lighting in an embodiment;

[0023] Figure 2 The figure is a flowchart of the method for preparing an LED light source for plant lighting in the embodiment;

[0024] Figure 3 The figure shows the spectrum of the LED light source in the first embodiment, where the abscissa is the wavelength and the ordinate is the light intensity; DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0026] See also Figure 1 As shown, the LED light source for plant lighting of this embodiment includes a bracket 1, a blue light LED chip 2, a red light LED chip 3, a first fluorescent glue layer 4, a second fluorescent glue layer 5 and a transparent cover 6.

[0027] The bracket 1 serves as a support body for the package. The surface of the bracket 1 is provided with a step 11, and the upper surface of the step 11 is covered with a transparent cover 5 to achieve sealing. A receiving cavity is formed between the cover 5 and the bracket 1. The blue LED chip 2 and the red LED chip 3 are arranged in the receiving cavity in a series or parallel manner, and are electrically connected to an external power supply. The first fluorescent glue layer 4 is coated on the blue LED chip 2, and the second fluorescent glue layer 5 is coated on the first fluorescent glue layer 4 and the red LED chip 3.

[0028] The bracket 1 can be made of PPA, PCT and EMC materials. PCT and EMC are preferred because they have fast heat dissipation. In one embodiment, an EMC bracket is selected because it has fast heat dissipation and can increase light extraction efficiency. The EMC bracket can be used for higher power, which is conducive to packaging multiple chips. By adjusting the number and ratio of the blue LED chip 2 and the red LED chip 3, the spectrum and photosynthetic quantum efficiency (PPE) can be adjusted.

[0029] In one embodiment, the emission wavelength of the blue LED chip 2 is 430-460nm, and the emission wavelength of the red LED chip 3 is 620-660nm. These two bands are the strongest for plant photosynthesis. Preferably, the emission wavelength peak wavelength of the blue LED chip 2 is a combination of 435-440nm, 445-450nm, and 455-460nm, and the emission wavelength of the red LED chip 3 is 655-660nm. The radiation intensity ratio of the emission wavelength peak wavelengths of the blue LED chip 2 is 435-440nm, 445-450nm, and 455-460nm is 1: (0.95-0.99): (0.90-0.94). The blue LED chip 2 can achieve a higher photosynthetic quantum efficiency (PPE) by regulating the epitaxy to achieve a combination of multiple peak wavelength bands to excite the phosphor, and the optimized peak combination has a higher PPE.

[0030] Preferably, the light radiation power ratio of the blue LED chip 2 and the red LED chip 3 is 1:(3-9), and this ratio is to adjust the entire spectrum and PPE to the best. If the ratio is too small, the red light is too strong, and the white light spectrum component is too low and is not suitable for plant cultivation; if the ratio is too high, the white light is too strong and the PPE value is too low.

[0031] The first fluorescent glue layer 4 includes a first fluorescent powder group and a first transparent glue that are fully and evenly mixed, wherein the first fluorescent powder group emits white light and near-infrared light under the excitation of the blue light. The first fluorescent glue layer 4 is evenly coated on the surface of the blue light LED chip 2, and the second fluorescent glue layer 5 can be dotted on the step surface of the bracket 1, the first fluorescent glue layer 4, the red light LED chip 3 and the inner surface of the cover.

[0032] The ratio of the second fluorescent powder to the second transparent glue in the second fluorescent glue layer 5 is 1:(10-20). If the ratio is too high, the far-red light intensity is too low and the planting effect cannot be achieved; if the ratio is too low, the infrared fluorescent powder has too high a specific gravity, which will cause serious absorption of white light and red light, thereby reducing the PPE of the entire light source.

[0033] In one embodiment, the first phosphor group includes a green phosphor with an emission peak wavelength of 500-550nm, a red phosphor with an emission peak wavelength of 600nm-660nm, a second phosphor group and a near-infrared phosphor with an emission peak wavelength of 710nm-730nm. The chemical formula of the green phosphor is at least one of Y3(Al, Ga)5O12:Ce3+ and Lu3Al5O12:Ce3+; the red phosphor is at least one of (Sr, Ca)AlSiN3:Eu2+ and Sr2Si5N8:Eu2+; the chemical formula of the near-infrared phosphor is at least one of Y3Al5O12:Cr3+ and Lu3Si5N11:Cr. The first phosphor group emits white light under the excitation of the blue light generated by the blue light LED chip.

[0034] In another embodiment, the first phosphor group includes green phosphor with emission peak wavelength of 530-540nm and red phosphor with emission peak wavelength of 620nm-630nm; the second phosphor group includes near-infrared phosphor with emission peak wavelength of 710nm-730nm.

[0035] The first phosphor group accounts for 15-50% of the first phosphor glue 41, and the first transparent glue accounts for 50-85%; and the lower the color temperature, the higher the proportion of the first phosphor group; the ratio of the second phosphor group to the second transparent glue in the second phosphor glue is 1: (10-20). The phosphor proportion can be adjusted according to the color temperature range, usually between 2700 and 7500K, and the lower the color temperature, the higher the phosphor proportion.

[0036] The transparent cover 5 is a silicone lens, and the refractive index ratio of the silicone lens to the second transparent glue is (1.01-1.03): 1. The main purpose of setting the refractive index ratio is to further improve the PPE of the device, mainly by optimizing the refractive index between silicone and silicone, thereby extracting more outgoing light and reducing the loss of light scattering and refraction. If the ratio is too low, the PPE improvement is not obvious. If the ratio is too high, it is not conducive to the stability of the device at high temperature, and it is easy to cause silicone delamination or cracking.

[0037] The LED light source for plant lighting provided by the present invention excites green phosphor and red phosphor through the blue light emitted by the blue LED chip 2, thereby generating a white light component. White light is the basic light source for plant photosynthesis, and its uniform distribution is crucial to the overall growth of the plant. The blue LED chip 2 can also excite near-infrared phosphor to produce near-infrared components that are beneficial to plants, further enriching the spectral components and improving the comprehensive efficiency of the plant supplementary light. The red LED chip 3 directly emits red light, increasing the red light component of the spectrum, and the red light component has a significant effect on promoting plant photosynthesis and flowering and fruiting. Since the red LED chip 3 and the blue LED chip 2 are encapsulated in the same light source, the red light can be more evenly distributed on the surface of the plant, avoiding the problem caused by the excessive spacing of the red light sources in the traditional supplementary light. The LED light source of the present invention achieves a uniform distribution of spectral components by encapsulating the blue LED chip 2 and the red LED chip 3 in the same LED light source, avoiding the problem of uneven distribution of spectral components in traditional plant lighting lamps. The design of using infrared phosphors instead of infrared chips reduces the production cost of lamps, further enriches the spectral composition, and improves the overall efficiency of plant lighting lamps.

[0038] First embodiment: An LED light source for plant lighting, comprising a bracket, a surface of which is provided with a step, the upper surface of the step is covered with a transparent cover, and a receiving cavity is formed between the transparent cover and the bracket; a blue light LED chip (wavelength is 437nm, 445nm, 457nm, blue light intensity ratio is 1:0.96:0.92) and a red light LED chip (peak wavelength is 657nm) connected in series, which are arranged in the receiving cavity; the surface of the blue light LED chip is coated with a first fluorescent glue layer, the first fluorescent glue layer comprises a fully and evenly mixed first fluorescent powder group and a first transparent glue, wherein the fluorescent powder wavelengths of the first fluorescent powder group are respectively 525nm green powder and 625nm red powder, and white light is emitted under the excitation of the blue light generated by the blue light LED chip; the first fluorescent glue layer and the red light LED chip are coated with a second fluorescent glue layer, the second fluorescent glue layer comprises a fully and evenly mixed second fluorescent powder group and a second transparent glue, wherein the second fluorescent powder group is a fluorescent powder with a peak wavelength of 725nm, and near-infrared light is emitted under the excitation of the blue light and red light LED chips. The radiation power ratio of the blue light chip and the red light chip is 1:3, and the refractive index ratio of the silicone lens and the second transparent glue is 1.02:1. Figure 3 , wavelength-light intensity diagram of the LED light source for plant lighting in this embodiment.

[0039] In order to further illustrate the technical effect of the LED light source of the present invention, the following is a comparison between specific embodiments and comparative examples:

[0040] Embodiment 1-8, Comparative Example 1-4: A LED light source for plant lighting, the specific preparation method thereof is as described above, and specific relevant parameters such as chip wavelength, radiation power ratio, etc. are shown in Table 1.

[0041] Comparative Example 5: A plant lamp light source, specifically including two light sources of white light and red light, the spectrum achieved by the mixture is the same as that of Example 4, and the parameters at the same power are shown in Table 2.

[0042] Table 1

[0043]

[0044]

[0045] Table 2

[0046]

[0047]

[0048] Note: Spectral uniformity refers to the uniformity of the spectrum during different tests of the lamp, including a comprehensive reference of brightness, spectral changes, etc.; spectral balance refers to the proportional coordination of various spectra of visible light when growing plants; the photonic quantum efficiency of the lamp refers to the PPE value of the 100W light bar test.

[0049] It can be seen from Table 1 and Table 2 that using different wavelengths and optimizing different ratios of blue light can help improve the quantum efficiency of light sources and lamps; when the red-to-blue ratio is in the range of 1:(3-9), it can be compatible with spectral balance and quantum efficiency; if the ratio is too high, the quantum efficiency is too low; if the ratio is too low, the spectral balance is too poor; when the refractive index ratio of the silicone lens and the second transparent glue is (1.01-1.03):1, it can take into account both the stability and quantum efficiency of the device; if the ratio is too low, the quantum efficiency is not significantly improved; if the ratio is too high, the device has too much light decay and is prone to failure.

[0050] join Figure 2 As shown, the present invention also proposes a method for preparing the above-mentioned LED light source for plant lighting, comprising the following steps:

[0051] Step 1 S1, encapsulating the blue LED chips and the red LED chips connected in series or in parallel on the upper surface of the bracket;

[0052] Step 2 S2, preparing a first fluorescent glue layer, fully mixing the first fluorescent powder group and the first transparent glue; coating the first fluorescent glue on the blue LED chip;

[0053] Step three S3, preparing a second fluorescent glue layer, and fully mixing the second fluorescent powder group with the second transparent glue; uniformly coating the second fluorescent glue below the step of the bracket to cover the first fluorescent glue layer and above the red LED chip;

[0054] Step 4 S4, forming a transparent cover by spot coating or molding on the upper surface of the step of the bracket.

[0055] In addition, the present invention also provides a plant lighting lamp, which includes the above-mentioned LED light source for plant lighting. The LED lamp for plant lighting of the present invention has a simple structure, is easy to manufacture and maintain, and is suitable for the growth environment of various plants. Therefore, the LED light source of the present invention has a very wide application prospect in plant lighting.

[0056] The above-described embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Equivalent changes and modifications made to the present invention by those skilled in the art should all fall within the scope of the claims attached to the present invention.

Claims

1. An LED light source for plant lighting, characterized in that: include A support, the surface of which is provided with a step, the upper surface of the step is covered with a transparent cover, and a receiving cavity is formed between the transparent cover and the support; A blue LED chip and a red LED chip connected in series or in parallel are arranged in the accommodating cavity; The surface of the blue LED chip is coated with a first fluorescent glue layer, wherein the first fluorescent glue layer comprises a first fluorescent powder group and a first transparent glue that are fully and evenly mixed, wherein the first fluorescent powder group emits white light under the excitation of the blue light generated by the blue LED chip; A second fluorescent glue layer is coated on the first fluorescent glue layer and the red light LED chip, and the second fluorescent glue layer includes a fully and evenly mixed second fluorescent powder group and a second transparent glue, wherein the second fluorescent powder group emits near-infrared light under the excitation of the blue light and red light LED chips.

2. The LED light source for plant lighting according to claim 1, characterized in that: The first phosphor group includes green phosphor with an emission peak wavelength of 500-550nm and red phosphor with an emission peak wavelength of 600-660nm; the second phosphor group includes near-infrared phosphor with an emission peak wavelength of 700-750nm.

3. The LED light source for plant lighting according to claim 1, characterized in that: The first phosphor group includes green phosphor with an emission peak wavelength of 530-540 nm and red phosphor with an emission peak wavelength of 620-630 nm; the second phosphor group includes near-infrared phosphor with an emission peak wavelength of 710-730 nm.

4. The LED light source for plant lighting according to claim 1, characterized in that: The emission peak wavelength of the blue LED chip is 430-460 nm, and the emission peak wavelength of the red LED chip is 620-660 nm.

5. The LED light source for plant lighting according to claim 4, characterized in that: The emission wavelength peak wavelength of the blue light LED chip is a combination of 435-440nm, 445-450nm, and 455-460nm, and the emission wavelength of the red light LED chip is 655-660nm.

6. The LED light source for plant lighting according to claim 5, characterized in that: The blue LED chip has a peak emission wavelength of 435-440nm, 445-450nm, and a radiation intensity ratio of 455-460nm of 1: (0.95-0.99): (0.90-0.94)。 7. The LED light source for plant lighting according to claim 4, characterized in that: The light radiation power ratio of the blue LED chip to the red LED chip is 1:(3-9).

8. The LED light source for plant lighting according to claim 1, characterized in that: The proportion of the first phosphor group in the first fluorescent glue layer is 15-50%, and the proportion of the first transparent glue is 50-85%; and the lower the color temperature, the higher the proportion of the first phosphor group; the ratio of the second phosphor group to the second transparent glue in the second fluorescent glue layer is 1: (10-20).

9. The LED light source for plant lighting according to claim 1, characterized in that: The transparent cover is a silicone lens. The ratio of the refractive index of the silicone lens to the refractive index of the second transparent glue is (1.01-1.03):

1.

10. A method for preparing an LED light source for plant lighting according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: Encapsulate the blue LED chips and the red LED chips connected in series or in parallel on the upper surface of the bracket; Step 2: prepare a first fluorescent glue layer, fully mix the first fluorescent powder group and the first transparent glue; and apply the first fluorescent glue on the blue LED chip; Step 3: prepare a second fluorescent glue layer, and fully mix the second fluorescent powder group with the second transparent glue; and evenly apply the second fluorescent glue below the step of the bracket to cover the first fluorescent glue layer and the top of the red LED chip; Step 4: spot-coating or molding the upper surface of the step of the bracket to form a transparent cover.

11. A plant lighting fixture, characterized in that: The lamp comprises the LED light source for plant lighting as described in any one of claims 1-9.

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