CN105405937A - Light source for plant growth and plant culture method - Google Patents

Abstract

A light source for plant growth and a plant cultivation method. The light source includes: the LED chip comprises a plurality of quantum wells with different emission wavelengths in an epitaxial structure; and the fluorescent powder and/or the quantum dots are used for being matched with the LED chip to obtain light covering the wavelength range required by plant growth. Furthermore, in the epitaxial structure of the LED chip, the emission wavelength of each quantum well sequentially increases along the direction gradually away from the light emitting surface. The light source provided by the invention comprises a plurality of quantum wells with different emission wavelengths in an epitaxial structure of a single LED chip, can achieve the coverage of a plurality of wavelengths or a large wavelength range, and can be packaged and driven by a conventional mode, so that the structure of the light source and a corresponding lighting device can be greatly simplified while the full coverage of the light wavelength required by plant growth is obtained, the cost is effectively reduced, and particularly, the occurrence of plant diseases and insect pests in the plant growth process can be effectively reduced or prevented by using red and far-red fluorescent powder and the like excited by green light in the light source.

Description

Light source for plant growth and plant cultivation method

technical field

The invention relates to a light source based on a semiconductor light emitting device, in particular to an LED-based light source for plant growth and a plant cultivation method.

Background technique

When plants grow, light is one of the most important conditions. Its quality, quantity and light time determine whether plants can grow healthily.

Specifically, illumination not only affects photosynthesis, but also affects plant photoperiod, light pattern and light orientation, etc. It determines the flowering/fruiting time of many plants, the height, fat and thinness of the plants, the direction of growth, and the nutritional components and content of the plants.

Due to different biochemical reactions, plants have different requirements for nutrient types and light wavelengths at different growth stages. For example, in the early stage of growth, it is mainly the growth and development of roots and seedlings. Some plants need nutrients related to nitrogen most, and nutrients such as phosphorus and potassium are also needed in the follow-up. As for the demand for light, in the process of seedling cultivation and initial growth, the main demand is light energy with short wavelengths, such as blue light. With the growth of a large number of leaves, flowers and fruits, plants need more and more long-wavelength photon energy, such as red light.

At present, in order to ensure the light quality (components of various wavelengths) in the process of plant growth, LED chips with multiple wavelengths are usually combined to cover the wavelength range of light required for plant growth. However, due to the narrow half-width of the luminous wavelength of the LED chip, generally in the range of 12-25nm, to cover the absorption peaks such as chlorophyll a, b and beta carotene, it is necessary to use multiple LED chips with different wavelengths. For example, in order to produce high-efficiency LED plant lighting, it is usually necessary to use LED chips with emission wavelengths of 430nm, 460nm, 485nm, 630nm, and 660nm, which makes LED packaging and control more complicated, and the cost will remain high.

Contents of the invention

The main purpose of the present invention is to provide a light source for plant growth and a plant cultivation method, thereby overcoming the deficiencies in the prior art.

In order to realize the aforementioned object of the invention, the technical solutions adopted in the present invention include:

Embodiments of the present invention provide a light source for plant growth, which includes:

LED chip, the epitaxial structure contains a plurality of quantum wells with different emission wavelengths;

Phosphor powder and/or quantum dots are used to cooperate with the LED chip to obtain light covering the wavelength range required for plant growth.

In some preferred embodiments, in the epitaxial structure of the LED chip, the emission wavelength of each quantum well increases sequentially along the direction gradually away from the light-emitting surface.

In some preferred implementation cases, the epitaxial structure of the LED chip includes quantum wells with an emission wavelength of 420-440 nm, quantum wells with an emission wavelength of 450-470 nm, and quantum wells with an emission wavelength of 480 nm, which are arranged in sequence along the direction gradually away from the light-emitting surface. ~500nm quantum wells.

In some preferred embodiments, the epitaxial structure of the LED chip contains quantum wells capable of emitting at least purple and blue light, and the phosphors and/or quantum dots include green, yellow, red phosphors and/or quantum wells. point.

In some particularly preferred embodiments, the epitaxial structure of the LED chip includes quantum wells capable of emitting green light, and the phosphors and/or quantum dots are selected from those that can be excited by green light and emit at a wavelength of 700-760nm. Light phosphors and/or quantum dots.

Further, the light source also includes blue and/or violet LED chips. Alternatively, the epitaxial structure of the LED chip further includes quantum wells capable of emitting purple and blue light, and the phosphors and/or quantum dots further include green, yellow, and red phosphors and/or quantum dots.

In some embodiments, the fluorescent powder and/or quantum dots are directly covered on the surface of the LED chip.

In some embodiments, the LED chip is covered with a transparent encapsulation material layer, and the phosphor and/or quantum dots are distributed in and/or covered on the encapsulation material layer.

In some embodiments, the phosphors and/or quantum dots are coated on and/or the phosphors and/or quantum dots are distributed within a continuous transparent film, and the transparent film is distributed in relation to the The corresponding position of the light emitting surface of the LED chip.

More preferably, along the set direction, among the phosphors and/or quantum dots distributed on and/or in the continuous transparent film, phosphors and quantum dots that can cooperate with the LED chip to emit light with a relatively long wavelength /or the proportion of quantum dots is gradually increased, and the proportion of phosphors and/or quantum dots that can cooperate with the LED chip to emit light with a relatively short wavelength is gradually reduced, and during the growth of the plant, the continuous transparent film along the The set direction sequentially passes through the light emitting surface of the LED chip.

An embodiment of the present invention also provides a plant cultivation method, which is implemented based on the light source used for plant growth, and the plant cultivation method includes: during the plant growth process, making the light source emit light and irradiating For the plant, as the growth time of the plant increases, the proportion of light with a relatively short wavelength in the light irradiated on the plant is gradually reduced, and the proportion of light with a relatively long wavelength is gradually increased.

Compared with the prior art, the advantages of the present invention are at least:

(1) The light source provided contains multiple quantum wells with different emission wavelengths in the epitaxial structure of a single LED chip, which can achieve the purpose of covering multiple wavelengths or a large wavelength range. Its structure is simple, and it can be packaged and driven by conventional methods. While achieving the goal of obtaining full coverage of the light wavelengths required for plant growth, the structure of the light source and the corresponding lighting device can be greatly simplified, and its cost can be effectively reduced;

(2) Preferably, the red light required for plant growth is obtained by using red and far-red (700-760nm) phosphors or quantum dots excited by green light and LEDs that can emit green light, and then combined with purple light, blue light and other LEDs The combination of chips or quantum wells that can emit blue light and purple light can not only achieve the purpose of obtaining full coverage of the light wavelengths required for plant growth, but also use the green light emitted by the light source to drive away insects, effectively reducing or preventing plant growth. The occurrence of pests and diseases.

Description of drawings

Fig. 1 is a schematic diagram of the epitaxial structure of an LED chip in a light source for plant growth in an embodiment of the present invention;

2 is a schematic diagram of a packaging structure of an LED chip in a light source for plant growth in an embodiment of the present invention;

Explanation of reference numerals: LED chip 1 , phosphor powder 2 , lead wire 3 , chip holder 4 , substrate 10 , first quantum well 20 , second quantum well 30 , third quantum well 40 , phosphor powder 50 .

detailed description

Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the invention is capable of various changes in different embodiments without departing from the scope of the invention, and that the description and illustrations therein are illustrative in nature and not limiting. this invention.

Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used in the description of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

The first embodiment of the present invention provides a light source for plant growth, which includes:

LED chip, the epitaxial structure contains a plurality of quantum wells with different emission wavelengths;

Phosphor powder and/or quantum dots are used to cooperate with the LED chip to obtain light covering the wavelength range required for plant growth.

More preferably, in the epitaxial structure of the LED chip, the emission wavelength of each quantum well increases sequentially along the direction gradually away from the light-emitting surface. Such a design can effectively reduce light loss due to absorption inside the LED chip.

For example, referring to Fig. 1, in an implementation of this embodiment, the epitaxial structure of the LED chip includes a third quantum well with an emission wavelength of 430nm and a third quantum well with an emission wavelength of 460nm arranged in sequence along the direction gradually away from the light-emitting surface. The second quantum well, the first quantum well with an emission wavelength of 480nm.

In an implementation of this embodiment, the epitaxial structure of the LED chip contains quantum wells capable of emitting purple and blue light, and the phosphors and/or quantum dots include green, yellow, red phosphors and/or Quantum dots, through the cooperation of the LED chip and the fluorescent powder and/or quantum dots, can achieve the purpose of obtaining full coverage of light wavelengths required for plant growth.

The LED chip in this embodiment can be manufactured by conventional epitaxial growth process such as MOCVD, and each quantum well can be formed in one epitaxial growth process. When it is applied, a conventional driving structure known in the industry can be used to realize the light emission of the LED chip.

Further, any suitable method known in the industry may be used to cooperate with the LED chip and the phosphor.

For example, in some implementations of this embodiment, the phosphor powder may directly cover the surface of the LED chip. The methods that can be used include: directly coating the phosphor powder on the surface of the LED chip by means of spraying, printing, coating, etc. to form a uniform phosphor layer, or depositing the phosphor powder on the surface of the LED chip by chemical and physical deposition. And a uniform phosphor layer is formed.

For example, in some implementations of this embodiment, the LED chip is covered with a transparent encapsulation material layer, and the phosphor is distributed in the encapsulation material layer and/or covers the encapsulation material layer. Wherein, the transparent encapsulation material layer may be formed of epoxy resin, organic silica gel, etc. known in the industry. In a more specific implementation, referring to FIG. 2, the LED chip 1 can be fixed in a chip holder 4, and the LED chip can be covered with a transparent encapsulation material doped with the phosphor powder 2. , and at the same time make the electrode of the LED chip conduct with the external power supply with the lead wire 3 etc., so that it can work normally.

In a more preferred solution, the phosphor powder and/or quantum dots can be coated on a continuous transparent film and/or the phosphor powder and/or quantum dots can be filled in a continuous transparent film, and the The transparent film is distributed at the position corresponding to the light-emitting surface of the LED chip, for example, directly covering the light-emitting surface of the LED chip, and there may be no gap or a gap between the transparent film and the LED chip, preferably using the latter way.

With this preferred solution, the light source can be used to provide plants with light of different wavelengths by using transparent films containing different phosphors and/or quantum dots to cooperate with the LED chip at different stages of plant growth. Irradiation meets the needs of plants at different growth stages. For example, in the process of raising seedlings and initial growth, the light source is used to provide the plants with light energy mainly of short wavelengths, while in the stages of leaf, flower and fruit growth, the light source is made to provide light energy of long wavelengths to the plants. .

In another preferred solution, the phosphor powder and/or quantum dots can be coated on a continuous transparent film and/or the phosphor powder and/or quantum dots can be filled into a continuous transparent film, and along the Setting the direction so that among the phosphors and/or quantum dots distributed on and/or in the film, the proportion of phosphors and/or quantum dots that can cooperate with the LED chip to emit light with a relatively long wavelength gradually As the LED chip increases, the proportion of phosphors and/or quantum dots that can cooperate with the LED chip to emit light with a relatively short wavelength gradually decreases, and during the growth of the plant, the continuous transparent film moves from the The light-emitting surfaces of the LED chips pass sequentially. In this way, as the plants grow, the light source can be used to provide the plants with different wavelengths of light irradiation to meet the needs of the plants in different growth stages.

In the light source for plant growth provided by the second embodiment of the present invention, the epitaxial structure of the LED chip can be basically the same as that of the first embodiment, but it can also include a quantum well capable of emitting green light, and the The phosphor powder and/or quantum dots also include phosphor powder and/or quantum dots that can be excited by green light to emit light with a wavelength of 700-760nm. Among them, the red light required for plant growth can be obtained by using red and far-red phosphors or quantum dots excited by green light. Cooperating with quantum wells such as purple light and blue light, it can achieve the purpose of full coverage of the light wavelengths required for plant growth.

The light source of the second embodiment may adopt substantially the same structural design and/or work in substantially the same manner as the light source of the first embodiment.

In the light source of the second embodiment, green light is used to excite red light. On the one hand, because the wavelength difference between green light and red light is relatively small, the stocks loss during light wavelength conversion is smaller than that excited by blue light. On the other hand, using Green light can repel insects, so red light excited by green light is beneficial to crop growth, and it is not easy to cause diseases and insect pests, avoiding plant pests that may be caused by the gathering of harmful insects caused by blue light and purple light.

It should be understood that the described embodiments of the present invention are for exemplary purposes only, and are not intended to limit the protection scope of the present invention. Those skilled in the art can make various other replacements, changes and improvements within the scope of the present invention. Accordingly, the present invention is not limited to the above-described embodiments, but only by the claims.

Claims (10)

1., for a light source for plant growth, it is characterized in that comprising:

LED chip, comprises the quantum well of a plurality of different emission in its epitaxial structure; And

Fluorescent material and/or quantum dot, obtain the light that cover plant grows required wave-length coverage in order to coordinate with described LED chip.

2. the light source for plant growth according to claim 1, is characterized in that: in the epitaxial structure of described LED chip, and edge is gradually away from the direction of light-emitting area, and the emission wavelength of each quantum well increases successively.

3. the light source for plant growth according to claim 2, is characterized in that: the epitaxial structure of described LED chip comprise along the emission wavelength set gradually away from the direction of light-emitting area be gradually the quantum well of 420 ~ 440nm, emission wavelength is the quantum well of 450 ~ 470nm, emission wavelength is the quantum well of 480 ~ 500nm.

4. the light source for plant growth according to claim 1, it is characterized in that: comprise the quantum well at least can launching purple, blue light in the epitaxial structure of described LED chip, and described fluorescent material and/or quantum dot comprise green, yellow, red fluorescence powder and/or quantum dot.

5. the light source for plant growth according to claim 1, it is characterized in that: the epitaxial structure of described LED chip comprises can the quantum well of transmitting green light, and described fluorescent material and/or quantum dot comprise and to be excited by green glow and emission wavelength is fluorescent material and/or the quantum dot of the light of 700 ~ 760nm.

6. the light source for plant growth according to claim 5, is characterized in that: described light source also comprises blue light and/or purple LED chip; Or the epitaxial structure of described LED chip also comprises the quantum well can launching purple, blue light, described fluorescent material and/or quantum dot also comprise green, yellow, red fluorescence powder and/or quantum dot.

7. the light source for plant growth according to claim 1, is characterized in that:

Described fluorescent material and/or quantum dot directly overlay described LED chip surface;

Or described LED chip is coated with transparent encapsulation material layer, described fluorescent material and/or quantum dot are distributed in described encapsulating material layer and/or cover on described encapsulating material layer.

8. the light source for plant growth according to claim 1, it is characterized in that: described fluorescent material and/or quantum dot are coated on continuous transparent membrane and/or described fluorescent material and/or quantum dot are distributed in continuous transparent membrane, and described transparent membrane is distributed in the exiting surface corresponding position with described LED chip.

9. the light source for plant growth according to claim 8, it is characterized in that: along direction initialization, be distributed on described continuous transparent membrane and/or in interior fluorescent material and/or quantum dot, can the ratio of the fluorescent material and/or quantum dot that send the light that wavelength is relatively grown be coordinated to promote gradually with described LED chip, the ratio of the fluorescent material and/or quantum dot sending the relatively short light of wavelength can be coordinated to reduce gradually with described LED chip, and in growing process, the exiting surface of described continuous transparent membrane along described direction initialization from described LED chip passes through successively.

10. a plant cultivation method, it is characterized in that it is implemented based on the light source for plant growth according to any one of claim 1-9, described plant cultivation method comprises: in growing process, make described light source luminescent and irradiate described plant, and along with the increase of plant growth time, the ratio of the light that the light medium wavelength making to be radiated at described plant is relatively short reduces gradually, and the ratio of the light that wavelength is relatively grown promotes gradually.