TWI742462B - Light-emitting diode element and uses of the same - Google Patents

Abstract

A light-emitting diode element for plant lighting is provided. The light-emitting diode element comprises: a blue light-emitting diode chip; an encapsulation material layer, which covers the blue light-emitting diode chip; and first phosphor powders dispersed in the encapsulation material layer and can be excited the blue light-emitting diode chip with an emission peak wavelength in the range of 650-655 nm and a full width at half maximum of less than 55 nm.

Description

Light-emitting diode element for plant lighting and its application

The present invention relates to a light-emitting diode (LED) element, in particular to a light-emitting diode element for plant lighting, and a lamp containing the light-emitting diode element.

In the 19th century, Russian botanist Andrei Famintsyn tried to apply artificial light sources to plant research, opening up various studies and researches on applying various light sources to plant growth and related chemical reactions. try. The research not only realizes the change of plant growth mode and cycle, but also enables plants to be mass-produced by artificial methods without being restricted by natural conditions. With the evolution of technology, the light source of plant lighting has evolved from incandescent lamps and fluorescent lamps to the currently commonly used high intensity discharge (HID) lamps. In addition, the luminous power of the lamp has been significantly improved with continuous research, and the emitted spectrum has also evolved from a full spectrum to a tunable spectrum. The above changes enable the plant lighting system to gradually replace sunlight from the early role of auxiliary sunlight to become the protagonist, and can start to supplement the specific spectrum required by plants.

In recent years, benefiting from the development of the semiconductor industry, light-emitting diode light sources (also referred to as "LED light sources" in this article) have provided another option for plant lighting. The LED light source not only has the advantages of low energy consumption and various color light types, but the full width at half maximum (fwhm) of each color light is also narrower than traditional light sources, which enables the LED light source to match the absorption spectrum required by plants. Easily combined to achieve effective use of light sources. For example, Figure 1 shows the absorption spectra of chlorophyll a (chlorophyll a) and chlorophyll b (chlorophyll b), which are necessary for photosynthesis of plants, and the emission spectra of red and blue LEDs. As shown in Figure 1, the core regions of the absorption spectra of chlorophyll a and chlorophyll b are the blue absorption region near 450 nanometers and the red light absorption region near 650 nanometers. Therefore, blue LEDs can provide the blue light band required for photosynthesis of chlorophyll a and chlorophyll b, and have the effect of promoting plant leaf growth, protein synthesis and fruit formation, and red LEDs can provide chlorophyll a and chlorophyll b for photosynthesis. The required red light band has the effect of promoting plant stem growth, carbohydrate synthesis and flowering. Therefore, the combined use of blue LED light source and red light LED light source to provide plant lighting, compared with traditional full-spectrum light sources (such as incandescent lamps), not only saves many unnecessary spectrum bands for chlorophyll, but also reduces lamps Energy consumption and heat dissipation burden.

However, the combined use of LED light sources with different light colors has several shortcomings in the spectrum system, including: LED light sources with different light colors need to be arranged in a specific arrangement to achieve a uniform light mixing effect. Not only is it difficult to mix light, but it also needs to be relatively complicated. The circuit layout of the LED light source is different; the life and the light attenuation degree of the LED light source of different light colors are different, and the error of the color light ratio is easy to appear after long-term use; and the peak width of the monochromatic LED light source is narrow and difficult to adjust, which is not conducive to the wide peak The combination of spectra.

In view of the above problems, a light-emitting diode element (also referred to as "LED element" in this article) combined with a monochromatic LED light source and a specific phosphor is a feasible technical means, in which a layer containing phosphor is arranged On a monochromatic LED light source, the monochromatic LED light source is used to excite the unique emission spectrum of the phosphor, so that the light emitted by the phosphor is mixed with the LED light passing through the phosphor layer to achieve a spectral combination and The effect of uniform light mixing. For example, CN 104465963 B discloses an _{LED element that uses CaAlSiN 3} :Eu (also referred to as "CASN") red phosphor and a blue LED light source. However, as shown in Figure 2, although the red light emitted by the CASN red phosphor can cover the red light band required for photosynthesis of chlorophyll a and chlorophyll b, its half-height width is too large, and it emits many pairs of chlorophyll. Useless energy, especially near-infrared light over 700 nanometers. In addition, other commonly used oxide, fluoride or nitride red phosphors also have the problem of too wide half-height, or the problem of blue or red wave crest positions.

In view of the foregoing technical problems, the present invention provides a light-emitting diode device in which a blue light-emitting diode chip and a red phosphor that can be excited by blue light to emit a specific spectrum is used. The emission spectrum of the light-emitting diode element of the present invention can fully correspond to the blue and red wavelengths required for photosynthesis of chlorophyll a and chlorophyll b, which can provide efficient plant lighting and greatly reduce energy waste.

Therefore, one object of the present invention is to provide a light emitting diode element for plant lighting, which includes: Blue light emitting diode chip; A layer of packaging material covering the blue light emitting diode chip; and The first phosphor is dispersed in the encapsulation material layer and can be excited by the light emitted by the blue light emitting diode chip. The emission peak is between 650nm and 655nm and the FWHM is less than 55nm The light.

In some embodiments of the present invention, the first phosphor is SrLiAl ₃ N ₄ :Eu ²⁺ phosphor, and the SrLiAl ₃ N ₄ :Eu ²⁺ phosphor is preferably a barium-containing nitride When it exists, it is prepared by hot isostatic pressing (hot isostatic pressing), in which the barium-containing nitride can be Ba ₃ N ₂ .

To a portion of the embodiment of the present invention, aspects, the aforementioned hot isostatic pressing sintering method based in an inert atmosphere, at a temperature of 800 ^o C to 1500 ^o C and the pressure of 10 MPa to 200 MPa.

In some embodiments of the present invention, the surface of the particles of the first phosphor may be subjected to surface coating treatment.

In some embodiments of the present invention, the light-emitting diode device further includes a second phosphor, which is different from the first phosphor and is dispersed in the encapsulation material layer, and is selected from the following Group: green phosphor, orange phosphor, infrared phosphor, and combinations thereof.

In some embodiments of the present invention, the surface of the particles of the second phosphor may be treated with a surface coating.

In some embodiments of the present invention, the blue light emitting diode chip emits light with a peak between 440 nm and 480 nm.

Another object of the present invention is to provide a lamp for plant lighting, which includes the light-emitting diode element as described above.

In order to make the above objectives, technical features and advantages of the present invention more obvious and understandable, the following is a detailed description of some specific implementation aspects.

The following will specifically describe some specific implementation aspects of the present invention; however, without departing from the spirit of the present invention, the present invention can still be practiced in many different forms, and the protection scope of the present invention should not be construed as being limited to the specification. The specific implementation status stated.

Unless otherwise specified, "a", "the" and similar terms used in this specification and the scope of the patent application shall be understood to include singular and plural forms.

Unless otherwise stated, the terms "first", "second" and similar terms used in this specification and the scope of the patent application are only used to distinguish the described elements or components, and have no special meaning in themselves and are not intended Refers to the order of precedence.

The effect of the present invention compared with the prior art is that the blue light emitting diode chip and the red phosphor that can be excited by blue light and emit a specific spectrum are used to prepare the light emitting diode device, so that the light emitting diode device of the present invention emits The emission spectrum can fully correspond to the blue and red wavelengths required for photosynthesis of chlorophyll a and chlorophyll b, which can provide efficient plant lighting and greatly reduce energy waste.

Specifically, the light-emitting diode device of the present invention includes a blue light-emitting diode chip, an encapsulating material layer, a first phosphor, and a second phosphor if necessary, as described below respectively.

1.1. Blue light emitting diode chip

The blue light emitting diode chip can be any light emitting diode chip that can emit blue light. Specifically, it can be any light-emitting diode chip that can emit light with a wavelength range of 400 nanometers to 500 nanometers and a wave peak of 430 nanometers to 450 nanometers. For example, the wavelength range can be between 410 nanometers to 500 nanometers, 420 nanometers to 500 nanometers, 430 nanometers to 500 nanometers, 440 nanometers to 500 nanometers, 450 nanometers to 500 nanometers, 460 nanometers To 500 nanometers, 470 nanometers to 500 nanometers, 480 nanometers to 500 nanometers, 490 nanometers to 500 nanometers, or a range constituted by any of the above two endpoints. The wave peak can be 435nm, 440nm, or 445nm.

Examples of blue light-emitting diode wafers include, but are not limited to, GaN-based light-emitting diode wafers, InGaN-based light-emitting diode wafers, InAlGaN-based light-emitting diode wafers, SiC-based light-emitting diode wafers, and ZnSe-based light-emitting diode wafers Chips, BN-based light-emitting diode chips, and BAlGaN-based light-emitting diode chips.

1.2. Encapsulation material layer

In the light-emitting diode element of the present invention, the packaging material layer covers the blue light-emitting diode chip to provide packaging functions. The material is not particularly limited and can be derived from any optical packaging known in the technical field of the present invention. Materials used include, but are not limited to, epoxy resin, silicone, etc.

1.3. First phosphor

The first phosphor is dispersed in the packaging material layer and can be excited by the light emitted by the blue light-emitting diode chip to emit light with a peak between 650 nm and 655 nm and a half-height width less than 55 nm . For example, the first phosphor can emit peaks between 650.5nm and 655nm, 651nm and 655nm, 651.5nm and 655nm, 652nm and 655nm, and 652.5nm and 655nm. Meters, 653 nanometers to 655 nanometers, 653.5 nanometers to 655 nanometers, 654 nanometers to 655 nanometers, 654.5 nanometers to 655 nanometers, or any of the above two endpoints of light, and The emitted light has 45nm to 54.5nm, 45.5nm to 54nm, 46nm to 53.5nm, 46.5nm to 53nm, 47nm to 52.5nm, 47.5nm to 52nm Meters, 48 nanometers to 51.5 nanometers, 48.5 nanometers to 51 nanometers, 49 nanometers to 50.5 nanometers, 49.5 nanometers to 50 nanometers, or the half-height width of the range formed by any of the above two endpoints.

In some implementations of the light-emitting diode device of the present invention, the first phosphor is SrLiAl ₃ N ₄ :Eu ²⁺ phosphor, in which Eu ²⁺ is an activator, and its content is not particularly limited. Those with ordinary knowledge in the technical field of the invention may make adjustments as needed. Generally speaking, based on the total content of 1 mol of Sr and Eu ²⁺ , the content of Eu ²⁺ can be 0.01 mol to 0.2 mol. Further, SrLiAl ₃ N _4: Eu ²⁺ phosphor powder is preferably based on the existence of a barium-containing nitride, hot isostatic pressing sintering method to obtain the SrLiAl ₃ N _4: Eu ²⁺ phosphor. Examples of the barium-containing nitride include, but are not limited to, Ba ₃ N ₂ , which can provide a fluxing effect to produce micron-level large-particle phosphors. The hot isostatic pressing sintering method is generally in an inert atmosphere, at a ^{temperature of 800 o} C to 1500 ^o C and a pressure of 10 MPa to 200 MPa, the composition of SrLiAl ₃ N ₄ : Eu ²⁺ phosphor The metal nitride of the metal element is sintered by hot isostatic pressing to form the SrLiAl ₃ N ₄ :Eu ²⁺ phosphor. For the specific implementation, please refer to the following examples.

_{The primary particle size distribution of the SrLiAl 3} N ₄ :Eu ²⁺ phosphor prepared by the hot isostatic pressing sintering method can reach a micron-level particle size ranging from 25 microns to 50 microns, for example, up to 26 microns, 27 microns, and 28 microns. , 29 microns, 30 microns, 31 microns, 32 microns, 33 microns, 34 microns, 35 microns, 36 microns, 37 microns, 38 microns, 39 microns, 40 microns, 41 microns, 42 microns, 43 microns, 44 microns, 45 Micrometers, 46 micrometers, 47 micrometers, 48 micrometers, or 49 micrometers, have more excellent light emission efficiency, heat resistance characteristics and low heat decay properties, making the light-emitting diode element of the present invention more suitable for long-term plant lighting. Maintain and promote the photosynthesis of plants with high efficiency and low cost.

Figure 3 Comparison of the absorption spectra of chlorophyll a and chlorophyll b with the emission spectra of red LED, blue LED, CaAlSiN ₃ :Eu (CASN) red phosphor and SrLiAl ₃ N ₄ :Eu ²⁺ (SLA) phosphor picture. As shown in Figure 3, the emission spectrum of SLA fluorescent powder not only covers the red light band required by chlorophyll a and chlorophyll b, but also reduces the unnecessary chlorophyll a and chlorophyll b by 10% compared to CASN red fluorescent powder The amount of photon emission greatly reduces the problem of energy waste.

1.3. Optional second phosphor

In the light-emitting diode device of the present invention, in addition to the first phosphor, a second phosphor that can be excited by blue light to emit light can be further included if necessary. The second phosphor is different from the first phosphor and is also dispersed in the packaging material layer. Examples of the second phosphor include, but are not limited to, selected from the following group: green phosphor, orange phosphor, infrared phosphor, and combinations thereof. In some embodiments of the present invention, green phosphor is used or as the second phosphor, and the green light emitted by the green phosphor can also promote the growth of some plants. When the second phosphor is an infrared phosphor that is excited by blue light and emits infrared light, it can stimulate the extension of the stem of the plant.

1.4. The composition of light-emitting diode components

The following illustrates the specific implementation of the light-emitting diode device of the present invention in conjunction with the accompanying drawings, but the present invention is not limited thereto.

FIG. 4 is a schematic diagram of an embodiment of the light-emitting diode device of the present invention. As shown in FIG. 4, the light-emitting diode element 400 includes a carrier base 401, a circuit 401a, an electrode terminal 401b, a blue light-emitting diode chip 402, a first phosphor 403a, an encapsulation material layer 404, and wires 405 The carrier base 401 is used to carry the blue light emitting diode chip 402, the packaging material layer 404 covers the blue light emitting diode chip 402, and the first phosphor 403a is dispersed in the packaging material layer 404.

The mixing ratio of the encapsulating material layer 404 and the first phosphor 403a will affect the ratio of blue and red light emitted by the light-emitting diode element. Increasing the content of the first phosphor 403a will increase the amount of the light-emitting diode element. The total amount of red light relatively reduces the total amount of blue light emitted by the light-emitting diode element. In the light-emitting diode device of the present invention, the weight ratio of the packaging material layer 404 to the first phosphor 403a is preferably 1:0.05 to 1:0.5, for example, 1:0.06, 1:0.07, 1:0.08, 1: 0.09, 1: 0.1, 1: 0.11, 1: 0.12, 1: 0.13, 1: 0.14, 1: 0.15, 1: 0.16, 1: 0.17, 1: 0.18, 1: 0.19, 1: 0.2, 1: 0.21 1: 0.22, 1: 0.23, 1: 0.24, 1: 0.25, 1: 0.26, 1: 0.27, 1: 0.28, 1: 0.29, 1: 0.3, 1: 0.31, 1: 0.32, 1: 0.33, 1: 0.34, 1: 0.35, 1: 0.36, 1: 0.37, 1: 0.38, 1: 0.39, 1: 0.4, 1: 0.41, 1: 0.42, 1: 0.43, 1: 0.44, 1: 0.45, 1: 0.46, 1:0.47, 1:0.48, or 1:0.49.

According to the light emitting diode device of the present invention, the surface of the first phosphor and optionally the second phosphor particles can be further treated with surface coating to provide the desired improved performance. For example, FIG. 5 is a schematic diagram of another embodiment of the light-emitting diode device of the present invention, in which the surface of the first phosphor 403a is surface-plated to have a surface plating layer 403b, and the surface plating layer 403b is used to improve water resistance , Prevent phosphor powder from agglomeration, or isolate phosphor powder to avoid unwanted chemical reactions. The surface coating is preferably transparent, and any organic coating material or inorganic coating material known in the technical field of the present invention can be used. Examples of organic plating materials include, but are not limited to, silicone polymer, poly(methyl methacrylate, PMMA), and polycarbonate (PC). Examples of inorganic coating materials include, but are not limited to, glass. Regarding the method of surface coating treatment on the surface of the phosphor particles, the conventional surface coating treatment method in the technical field of the present invention can be used. For example, a sol-gel method, chemical vapor deposition method, physical vapor deposition method, or solution adsorption method may be used to cover the surface of the first phosphor particles with a surface coating, but the present invention is not limited to this.

2. Lamps and lanterns for plant lighting

The light-emitting diode element of the present invention can be used for plant lighting. Therefore, the present invention also provides a lamp for plant lighting, which uses the light-emitting diode element of the present invention as the light source as described above.

The present invention is further illustrated with the following specific embodiments.

3. Example

3.1. SrLiAl ₃ N ₄ :Eu ²⁺ Preparation of phosphor

Weigh barium nitride (Ba ₃ N ₂ ), strontium nitride, lithium nitride, aluminum nitride and europium nitride. The molar ratio of Ba:Sr:Li:Al:Eu is 0.1:0.98:1: 3: 0.02, and grind in a boron nitride mortar for 30 minutes. Then in a hot isostatic pressing sintering furnace (model: AIP6-30H), sintering in a nitrogen atmosphere for four hours at a temperature of ^{1000 o C and a pressure of 100 MPa.} Finally, the obtained product is ground in a mortar to obtain SrLiAl ₃ N ₄ :Eu ²⁺ phosphor. The primary particle size distribution range of the SrLiAl ₃ N ₄ :Eu ²⁺ phosphor is from 5 microns to 50 microns, and the average particle size is from 10 microns to 15 microns.

3.2. Preparation of light-emitting diode components

[Example 1]

The blue light emitting diode chip (the wavelength range of blue light is between 410nm and 480nm and the wave peak is 440nm) is placed on a rectangular carrier base and connected with wires, circuits and electrode terminals, such as Figure 4 shows the meaning.

Mix liquid silicone resin with SrLiAl ₃ N ₄ :Eu ²⁺ phosphor in a weight ratio of 1:0.2 to prepare a colloidal mixture with a total weight of 10 grams. Next, put the colloidal mixture into a vacuum degassing mixer for mixing and degassing. Subsequently, the degassed colloidal mixture is placed in a dispenser, and the colloidal mixture is covered on the blue light-emitting diode wafer in a dispensing manner. Thereafter, the mixture was covered with colloidal blue light emitting diode chip in a baking oven for 8 hours at 120 ^o C, so that the gel mixture cured to give a light-emitting diode element.

Place the light-emitting diode element on the stage of the spectrometer (instrument model: FluoroMax-3, manufactured by HORIBA) and energize to measure the emission spectrum. The emission spectrum of the light-emitting diode device of Example 1 is shown in FIG. 6.

[Example 2]

The light-emitting diode device was prepared in the same manner as in Example 1, except that the weight ratio of the _{liquid silicone resin to the SrLiAl 3} N ₄ :Eu ^{2+ phosphor was adjusted to 1:0.13.} The emission spectrum of the light-emitting diode device of Example 2 is shown in FIG. 7.

As shown in Figure 6, the light system emitted by the light-emitting diode device of Example 1 includes blue light with a peak of 440 nm and red light with a peak of 652 nm and a half-height of 50 nm. The intensity is greater than the intensity of blue light. This shows that the wavelength band of the light emitted by the light-emitting diode device of the present invention can cover and match the absorption spectra of chlorophyll a and chlorophyll b, so it is particularly suitable for use in promoting and maintaining photosynthesis of plants.

In addition, as shown in FIG. 7, the light system emitted by the light-emitting diode device of Example 2 includes blue light with a peak of 440 nm and red light with a peak of 652 nm and a half-height of 50 nm. The intensity of light is smaller than the intensity of blue light. This shows that the intensity of blue and red light can be changed by adjusting _{the weight ratio of silicone resin to SrLiAl 3} N ₄ :Eu ²⁺ phosphor. Therefore, those with ordinary knowledge in the technical field of the present invention can adjust it according to actual needs. The weight ratio of silicone resin to SrLiAl ₃ N ₄ :Eu ²⁺ phosphor is used to obtain the required light-emitting diode device.

The above-mentioned embodiments are only illustrative to illustrate the principle and effects of the present invention, and to illustrate the technical features of the present invention, and are not intended to limit the scope of protection of the present invention. Any changes or arrangements that can be easily made by those skilled in the art without departing from the technical principle and spirit of the present invention fall within the claimed scope of the present invention. Therefore, the protection scope of the present invention is as listed in the appended patent scope.

400: Light-emitting diode element 401: Carrying base 401a: Circuit 401b: Electrode terminal 402: blue light emitting diode chip 403a: the first phosphor 403b: Surface coating 404: Encapsulation material layer 405: Wire

Figure 1 is a graph comparing the absorption spectra of chlorophyll a and chlorophyll b with the emission spectra of conventional red LEDs and blue LEDs.

Figure 2 is a comparison diagram of the absorption spectra of chlorophyll a and chlorophyll b and the emission spectra of red LED, blue LED, and CaAlSiN ₃ :Eu (CASN) phosphor.

Figure 3 Comparison of the absorption spectra of chlorophyll a and chlorophyll b with the emission spectra of red LED, blue LED, CaAlSiN ₃ :Eu (CASN) phosphor, and SrLiAl ₃ N ₄ :Eu ²⁺ (SLA) phosphor picture.

FIG. 4 is a schematic diagram of an embodiment of the light-emitting diode device of the present invention.

FIG. 5 is a schematic diagram of another embodiment of the light-emitting diode device of the present invention.

Fig. 6 is the emission spectrum of one embodiment of the light-emitting diode device of the present invention.

Fig. 7 is the emission spectrum of another embodiment of the light-emitting diode device of the present invention.

Claims (8)

A light emitting diode element for plant lighting, comprising: a blue light emitting diode chip; a packaging material layer covering the blue light emitting diode chip; and a first phosphor dispersed in the packaging material layer, and It can be excited by the light emitted by the blue light-emitting diode chip and emit light with a peak between 650 nm and 655 nm and a half-height width less than 55 nm. The first phosphor is SrLiAl ₃ N ₄ : Eu ²⁺ phosphor, and the SrLiAl ₃ N ₄ : Eu ²⁺ phosphor is prepared by hot isostatic pressing in the presence of barium-containing nitride. The light-emitting diode device according to claim 1, wherein the barium-containing nitride is Ba ₃ N ₂ . The light-emitting diode device according to claim 1, wherein the hot isostatic pressing sintering method is performed in an inert atmosphere at a temperature of 800° C. to 1500° C. and a pressure of 10 MPa to 200 MPa. The light-emitting diode device according to any one of claims 1 to 3, wherein the surface of the particles of the first phosphor is surface-plated. The light-emitting diode device according to any one of claims 1 to 3, further comprising a second phosphor, which is different from the first phosphor and is dispersed in the encapsulation material layer, and is Selected from the following group: green phosphor, orange phosphor, infrared phosphor, and combinations thereof. The light-emitting diode device according to claim 5, wherein the surface of the particles of the second phosphor is surface-plated. The light-emitting diode device according to claim 1, wherein the blue light-emitting diode chip emits light with a crest between 440 nm and 480 nm. A lamp for plant lighting, which contains the light-emitting diode element according to any one of claims 1 to 7.

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