TWI658610B - Quantum-dot-based color-converted light emitting device and method for manufacturing the same - Google Patents

Abstract

The invention provides a light-emitting device, which includes: a flip-chip LED wafer; a photoluminescence structure disposed on the LED wafer; and a moisture barrier reflection structure covering the side of the photoluminescence structure and the facade of the LED wafer. The photoluminescent structure includes a first photoluminescent layer, a light transparent isolation layer, a second photoluminescent layer, and a light transparent moisture barrier layer sequentially stacked. In a preferred embodiment, the LED chip emits blue light, the first photoluminescent layer includes a red fluorescent material, and the second photoluminescent layer includes a green quantum dot; thereby, the red fluorescent material of the first photoluminescent layer The blue part of the higher energy level can be converted into the red light of lower energy level first, which reduces the unconverted blue light intensity of the green quantum dots and effectively avoids the photooxidation of the quantum dots. The present invention further provides a method for manufacturing the light-emitting device.

Description

Light emitting device applying quantum dot color conversion and manufacturing method thereof

The invention relates to a wafer-level packaged light-emitting device and a manufacturing method thereof, and in particular to a wafer-level packaged light-emitting device using a green quantum dot material and red phosphor and a manufacturing method thereof.

Quantum dot (QD) material is a semiconductor crystal material with a nanometer size. Its particle size usually ranges from 1 nanometer to 50 nanometers. After being irradiated by high-level light, due to quantum confinement effects (Quantum confinement effect), the quantum dot material can convert part of the incident light into another lower-level visible light, so the quantum dot material can be used as a photoluminescence material. By changing the particle size, shape, or material composition of the quantum dot material, the quantum dot material can be made to emit visible light with different wavelengths, that is, its emission spectrum is changed.

Compared with traditional fluorescent materials, such as yttrium aluminum garnet (YAG) phosphors, nitrides (Nitride) or nitrogen oxides (Oxynitride) phosphors, the emission spectrum of quantum dot materials has a significantly narrower half-height Wide (Full Width at Half Maximum, FWHM), therefore, when using quantum dot materials with LED chips to form an LED light emitting device as a backlight source of a display, the color purity of the display can be improved. Compared with the organic light emitting diode (OLED) display which can reach 70% of the BT.2020 color gamut (Color Gamut), the application of quantum dot material display In terms of color performance, the device can have a color gamut range of up to 90% BT.2020; in addition, compared with OLEDs that are organic materials, their service life is shorter, while quantum dot materials are inorganic materials, and their service life is relatively long. On the other hand, the light emitting device using quantum dot materials can directly replace the backlight source of the existing liquid crystal display, and the color gamut range of the liquid crystal display can be significantly increased only by changing the photoluminescent material.

Although the light emitting device with quantum dot material and LED chip has the above advantages, there are still some problems in practice that need to be improved or overcome. For example, the thermal stability of a quantum dot material is not good, and its efficiency will be significantly attenuated in a high temperature environment (for example, an environment greater than 70 ° C). Therefore, the thermal energy generated during the operation of the LED chip may significantly reduce the efficiency of the quantum dot material.

In addition, when the quantum dot material comes into contact with water vapor or oxygen in the air, the surface is easily oxidized to form an oxide, which causes the light emitting intensity of the quantum dot material to decrease. Therefore, the light emitting device using the quantum dot material must have good moisture barrier. Only in order to protect the water vapor and oxygen from the outside from penetrating inward and contact the quantum dot material, so that the light-emitting device has a longer service life.

Furthermore, in the presence of oxygen or water vapor around the quantum dot material, when excited by higher energy levels of light (such as ultraviolet or blue light), photo-oxidation is more likely to occur, resulting in intensity of light emission. ) And the "blue shifting" of the emission spectrum. Specifically, when high-level light is irradiated to semiconductor materials such as quantum dots, due to the photovoltaic effect, the semiconductor material will generate a large number of electrons and holes, and the excited free electrons make it easy for the surface of the semiconductor material to surround the surface. Dissociation of oxygen molecules to form oxygen atoms and oxygen ions, promote semiconductor materials to react more easily with oxygen to form oxides; thesis and scholar of Young EM Appl Phys A 47: 259-69, 1988 The paper by Sato S. equals 1997 J Appl Phys 81: 1518 has many experimental verifications and descriptions of the photo-oxidation phenomenon of electron-active semiconductor materials. Therefore, the quantum dot material will significantly accelerate its oxidation reaction under the irradiation of high-level light.

At the same time, after the surface of the quantum dot is oxidized, the effective particle size of the quantum dot material will be reduced. Since the quantum dot photoluminescence material with a smaller particle size can generate higher-level converted light (that is, a shorter wavelength), the quantum dot After the surface of the material is oxidized, its luminescence spectrum will be shifted toward a short wavelength, so-called "blue shifting" phenomenon occurs. In addition, the generation of oxides will increase the structural defects of the quantum dots, which will cause electrons and holes to combine in a non-radiative electron-hole recombination when the photoelectric effect is applied. This combination of non-luminous electron holes will release energy in the form of thermal energy, and will not be converted into lower-level photons. Therefore, the photo-oxidation phenomenon of the quantum dot material will also cause its luminous intensity to decrease, eventually making the quantum dots Re-emission, this is the photobleaching phenomenon of quantum dots. Therefore, when quantum dot materials are applied to LED light-emitting devices, it is necessary to prevent the quantum dot materials from being irradiated with excessively high-level light rays, so as to avoid the light attenuation and blue shift of the light emission spectrum caused by the photo-oxidation phenomenon.

In addition, light-emitting devices using quantum dot color conversion usually need to uniformly disperse quantum dot materials in a binder to obtain good light-emitting efficiency. However, not all quantum dot materials are compatible with all glues. Generally, the surface of the quantum dots needs to be modified, such as the formation of ligands, in order to uniformly disperse the quantum dots in a specific glue; therefore, Surface modification, selection of specific adhesive materials, and process compatibility between different adhesive materials have also become important technical challenges to realize the application of quantum dot materials to LED light-emitting devices.

In summary, how to better improve or overcome any of the above problems to apply quantum dot materials to LED light-emitting devices is exactly the technical problem to be solved in the LED industry at present.

An object of the present invention is to provide a light-emitting device using quantum dot color conversion and a manufacturing method thereof. The light-emitting device is a wafer-level packaged light-emitting device, which uses a flip-chip LED chip and has a low thermal resistance heat dissipation path to reduce the LED chip junction Temperature (Junction Temperature), so it can effectively improve the thermal attenuation of the quantum dot material and reduce the temperature to which the quantum dot material is subjected.

An object of the present invention is to provide a light emitting device using quantum dot color conversion and a manufacturing method thereof. The light emitting device has good hermetic seal for reducing moisture or oxygen in the outside air. Contact with quantum dot materials can effectively improve the oxidation of quantum dot materials.

An object of the present invention is to provide a light-emitting device using quantum dot color conversion and a manufacturing method thereof. A fluorescent material that is not easily photo-oxidized is placed between the quantum dot material that is more easily photo-oxidized and the LED chip, which can effectively reduce the incidence of light. The light intensity of the high-level light rays of the quantum dot material does not exceed the capacity of the quantum dot material, so as to improve the photo-oxidation phenomenon of the quantum dot material.

An object of the present invention is to provide a method for manufacturing a light-emitting device using quantum dot color conversion. The adhesive glue required for fixing fluorescent materials and the adhesive glue required for fixing quantum dot materials have different characteristics. The glue curing process It is also incompatible. The light emitting device can effectively block the polymer material used for fixing the quantum dot material and the polymer material used for fixing the fluorescent material, so as to avoid the problem of incompatibility between the two processes or material characteristics.

To achieve the above object, the proposed light emitting device may include: a flip-chip LED chip for providing a first light, the first light is a blue light, a dark blue light, a purple light or an ultraviolet light; a photo-induced The light emitting structure is disposed on an upper surface of one of the flip-chip LED chips, and It includes a first photoluminescent layer, a light transparent isolation layer, a second photoluminescent layer, and a light transparent moisture barrier layer. The light transparent isolation layer is disposed on the first photoluminescent layer, and the second A photoluminescent layer is disposed on the phototransparent isolation layer, and the phototransparent moisture barrier layer is disposed on the second photoluminescent layer, wherein the first photoluminescent layer includes a first polymer material and a mixture A lower excitation energy level fluorescent material (such as a red fluorescent material) in the first polymer material, and the second photoluminescent layer includes a second polymer material and mixed with the second polymer One of the materials with a higher excitation energy level quantum dot material (such as a green quantum dot material); and a moisture blocking reflection structure covering one side of the photoluminescence structure and one facade of the flip-chip LED chip, And not lower than an electrode surface of the flip-chip LED chip; wherein the lower excitation energy level fluorescent material of the first photoluminescent layer is used for a part of the first light (such as blue light) Into a longer wavelength of visible light (such as red light) A first light (e.g., blue) of light intensity change is reduced, in order to achieve a higher light intensity is not larger than the excitation energy level of the quantum dot material (e.g. green quantum dot material) can withstand it. The manufacturing method of the light-emitting device disclosed in the present invention may include: bonding a photoluminescence structure to a flip-chip LED chip; and forming a moisture blocking reflection structure to cover one side of the photoluminescence structure and the A facade of a flip-chip LED chip.

Therefore, the light-emitting device provided by the present invention can provide at least the following beneficial technical effects:

1. Relative to the position of the flip-chip LED chip, the second photoluminescent layer is disposed above the first photoluminescent layer, so a part of the first light emitted by the flip-chip LED chip will be It is first converted by the first photoluminescent layer to reduce the dose of the quantum dot material (such as green quantum dot material) with a higher excitation energy level irradiated by the first light into the second photoluminescent layer. Therefore, the light intensity of the first light irradiated to the quantum dot material with a higher excitation energy level is not greater than the light intensity it can withstand. Degree, can effectively inhibit or avoid photo-oxidation of quantum dot materials with higher excitation energy levels.

2. The light emitting device does not need a packaging bracket, so it can have a large light emitting area under the same packaging volume, so it can effectively reduce the blue light unit area intensity of the quantum dot material to reduce the photooxidation of the quantum dot material.

3. Both the light transparent moisture barrier layer and the moisture barrier reflective structure have low water vapor permeability, which makes it difficult for the external water vapor and oxygen to penetrate it and contact the quantum dot material in the second photoluminescent layer. , Can effectively avoid or reduce the oxidation of quantum dot materials.

4. The optically transparent isolation layer separates the second photoluminescent layer from the first photoluminescent layer so that they are not in contact with each other, in other words, a second polymer material used to glue quantum dot materials with higher excitation energy levels It will not be in contact with the first polymer material used for gluing a fluorescent material with a lower excitation energy level (such as a red fluorescent material), and therefore will not affect each other's material characteristics or process characteristics (such as curing mechanism).

5. Compared with a light-emitting device using a packaging bracket or a packaging substrate, a wafer-level packaged light-emitting device using a flip-chip LED chip has a lower thermal resistance, which can effectively reduce the junction temperature of the LED chip, and the second photoluminescence The layer is far away from the flip-chip LED chip, so the thermal energy generated by the flip-chip LED chip has less effect on the quantum dot material, which can reduce the temperature to which the quantum dot material is subjected, for example, lower than 50 ° C, 40 ° C, or 30 ° C. , Effectively improve the thermal decay phenomenon of quantum dot materials.

6. When the fluorescent material with a lower excitation energy level used in the first photoluminescent layer is a fluoride fluorescent material (that is, KSF or MGF), since KSF and MGF are not excited by green light, the Higher-energy-level light (such as green light) emitted by quantum dot materials with high excitation energy levels is effectively scattered outward, so the overall light extraction efficiency of the light-emitting device can be increased.

In order to make the above objectives, technical features and advantages more obvious and easy to understand, the following is a comparison The preferred embodiment is described in detail with reference to the drawings.

1 ~ 3‧‧‧light-emitting device

10‧‧‧ flip-chip LED chip, LED chip

101‧‧‧ top surface

102‧‧‧ electrode surface, lower surface

103‧‧‧ facade

104‧‧‧electrode set

20‧‧‧Photoluminescence structure, PL structure

201‧‧‧Top

202‧‧‧ underside

203‧‧‧side

21‧‧‧First photoluminescent layer, first PL layer

211‧‧‧The first polymer material

212‧‧‧Fluorescent material with lower excitation energy level, red fluorescent material

22‧‧‧light transparent isolation layer

23‧‧‧second photoluminescent layer, second PL layer

231‧‧‧Second polymer material

232‧‧‧Higher quantum dot material, green quantum dot material, green QD material

233‧‧‧light scattering particles

234‧‧‧ blue quantum dot material

24‧‧‧light transparent moisture barrier

25‧‧‧ light transparent thermal conductive layer

26‧‧‧ light transparent separation layer

30‧‧‧ Moisture blocking reflective structure, reflective structure

301‧‧‧Top

302‧‧‧ underside

31‧‧‧The third polymer material

32‧‧‧ light scattering particles

40‧‧‧light guide structure

401‧‧‧Top

402‧‧‧inclined side

900‧‧‧ Release Material

B‧‧‧ Blu-ray, Blu-ray spectrum

G, G1, G2‧‧‧‧ Green, Green spectrum

R‧‧‧Red light, red light spectrum

FIG. 1A and FIG. 1B are two cross-sectional views of a light-emitting device according to a first preferred embodiment of the present invention; FIG. 1C is a cross-section of another aspect of a light-emitting device according to the first preferred embodiment of the present invention. 2A and 2C are schematic diagrams of another cross-section of a light emitting device according to the first preferred embodiment of the present invention, showing light conversion and transmission; and FIG. 2B is a schematic view of the first preferred embodiment according to the present invention. Measurement results of the emission spectrum of the light-emitting device; FIG. 3 is a schematic cross-sectional view of a light-emitting device according to a second preferred embodiment of the present invention; FIG. 4A is a schematic cross-sectional view of a light-emitting device according to a third preferred embodiment of the present invention Figure 4B is a schematic cross-sectional view of another aspect of a light-emitting device according to a third preferred embodiment of the present invention; Figures 5A to 5I are manufacturing methods of a light-emitting device according to a preferred embodiment of the present invention FIG. 6A to FIG. 6D are schematic steps of a method for manufacturing a light emitting device according to a preferred embodiment of the present invention.

Please refer to FIG. 1A and FIG. 1B, which are schematic diagrams of a light emitting device 1 according to a first preferred embodiment of the present invention. The light-emitting device 1 may include a flip-chip LED chip 10, a photo-induced The light-emitting structure 20 and a moisture-blocking reflective structure 30 will be described in order as follows.

The flip-chip LED chip (hereinafter referred to as the LED chip) 10 is used to provide a first light (or main light), which can be a blue light, a dark blue light, a purple light, or an ultraviolet light with a higher energy level; Taking a blue light LED chip as an example, the first light provided by the LED chip 10 is blue light. The wafer 10 may include an upper surface 101, a lower surface 102, a vertical surface 103, and an electrode group 104. The upper surface 101 and the lower surface 102 are opposite and opposite to each other. The vertical surface 103 is formed on the upper surface 101 and the lower surface 102. And connects the upper surface 101 and the lower surface 102 in other words, in other words, the facade 103 is formed along the edge of the upper surface 101 and the edge of the lower surface 102, so the facade 103 is annular with respect to the upper surface 101 and the lower surface 102 (for example, Rectangular ring).

The electrode group 104 is disposed on the lower surface 102 and may have more than two electrodes. Since the electrode group 104 is disposed thereon, the lower surface 102 is also referred to as the electrode surface 102; in other words, the electrode surface 102 does not refer to the lower surface of the electrode 104. The LED chip 10 can convert electric energy (not shown) through the electrode group 104 to emit light in a wavelength range corresponding to the first light (blue light); most of the light can be emitted from the upper surface 101 and the vertical surface 103.

On the other hand, compared with a light-emitting device using a bracket or a substrate, the light-emitting device 1 disclosed in the present invention is a wafer-level packaged light-emitting device. One of its technical features is that the LED chip 10 is a flip-chip wafer and can be directly bonded to a printed circuit. The board or other application substrate does not include a bracket, so it has low thermal resistance, and the thermal energy generated during its operation can be more directly dissipated through the electrode group 104, reducing the impact of thermal energy on other structures.

After being excited by the first light emitted from the LED chip 10, the photoluminescent (PL) structure 20 can absorb part of the first light and convert it into lower-level light (such as red light and green light). Then part of the unconverted first light (such as blue light) and red light and The green light is mixed to form a light of a desired color (for example, white light).

In appearance, the photoluminescence structure (hereinafter referred to as the PL structure) 20 may include a top surface 201, a bottom surface 202, and a side surface 203. The top surface 201 and the bottom surface 202 are opposite and oppositely disposed, and the side surface 203 is formed on the top surface 201 and The bottom surface 202 is connected between the top surface 201 and the bottom surface 202. In other words, the side surface 203 is annular (for example, a rectangular ring) with respect to the top surface 201 and the bottom surface 202.

In position, the PL structure 20 is disposed on the LED chip 10, and the bottom surface 202 of the PL structure 20 is located on the upper surface 101 of the LED chip 10, and the bottom surface 202 can directly cover the upper surface 101, but does not cover the facade of the LED chip. 103; However, the embodiment of the distance between the bottom surface 202 and the upper surface 101 is not excluded, indicating that other structures or materials may be provided between the PL structure 20 and the LED chip 10 (not shown). In addition, the bottom surface 202 may be slightly larger than the upper surface 101, but is not limited thereto.

Structurally, the PL structure 20 includes a first photoluminescent layer (hereinafter referred to as the first PL layer) 21, a light transparent isolation layer 22, a second photoluminescent layer (hereinafter referred to as the second PL layer) 23, and A light transparent moisture barrier layer 24 is sequentially stacked along the normal direction of the upper surface 101 of the LED chip 10, that is, the first PL layer 21 is disposed on the upper surface 101 of the LED chip 10, and the light transparent isolation layer 22 is disposed on the first PL layer 21, the second PL layer 23 is disposed on the light transparent isolation layer 22, and the light transparent moisture barrier layer 24 is disposed on the second PL layer 23.

The first PL layer 21 can generate a lower energy level light (such as red light) when the first light layer is excited, which can include a first polymer material 211 and a lower excitation energy level fluorescent material (such as red color). Fluorescent material) 212. In order to simplify the description, the following will take the red fluorescent material 212 and the red light emitted by it as an example for technical description. The red fluorescent material 212 can be uniformly mixed and glued (fixed) in the first polymer material 211. The red fluorescent material 212 can be partially converted into red light after being excited by the first light with a higher energy level; in other words, after the first light passes through the first PL layer 21, it is partially converted to red Light, the light intensity of some unconverted first rays will decrease accordingly; the technical content of this aspect will be further explained with reference to FIG. 2A later. In addition, compared with a quantum dot material (such as a green quantum dot material) 232 described later, a fluorescent material (such as a red fluorescent material) 212 can withstand higher temperatures, and therefore can be closer to or contact the LED chip 10.

The red fluorescent material 212 may include, but is not limited to, those that can produce red light such as a fluoride fluorescent material or a nitride fluorescent material; the fluoride fluorescent material may be, for example, a KSF fluorescent material, which may include at least the following One of them: (A) A ₂ [MF ₆ ]: Mn ⁴⁺ , where A is selected from Li, Na, K, Rb, Cs, NH ₄ and combinations thereof, and M is selected from Ge, Si, Sn, Ti, Zr And combinations thereof; (B) E ₂ [MF ₆ ]: Mn ⁴⁺ , wherein E is selected from Mg, Ca, Sr, Ba, Zn and combinations thereof, and M is selected from Ge, Si, Sn, Ti, Zr and combinations thereof ; (C) Ba _0.65 Zr _0.35 F _2.70 : Mn ⁴⁺ ; or (D) A ₃ [ZrF ₇ ]: Mn ⁴⁺ , wherein A is selected from Li, Na, K, Rb, Cs, NH ₄ and combinations thereof. Other fluoride fluorescent materials may be, for example, MGF fluorescent materials, which may include at least one of the following: (xa) MgO. (A / 2) Sc ₂ O ₃ .yMgF ₂ .cCaF _2. (1-b) GeO _2. (B / 2) Mt ₂ O ₃ : zMn ⁴⁺ ; Among them, 2.0 x 4.0, 0 <y <1.5, 0 <z <0.05, 0 a <0.5, 0 <b <0.5, 0 c <1.5, y + c <1.5, and Mt is selected from at least one of Al, Ga, and In.

The light generated by the above-mentioned types of fluoride fluorescent materials has a narrow half-wave width, and the wavelength of the light source that can be excited is less than 500 nm, so it will not be excited by the green light generated by the second PL layer 23, so The overall light extraction efficiency (Light Extraction Efficiency) of the light-emitting device 1 can be increased; the technical content of this aspect will be further described with reference to FIG. 2C later.

The first polymer material 211 may include, but is not limited to, a resin material or a silicone material. Since the first PL layer 21 is closer to the heat source LED chip 10, the first polymer material 211 needs to have better heat resistance. For example, it is a heat-cured Silicone material, which may include a platinum Platinum Silicone or Tin Silicone. Platinum Platinum Silicone has better heat resistance. Therefore, the light emitting device 1 preferably uses Platinum Platinum Silicone as the first polymer material 211. Platinum catalyst silicone is a platinum catalyst contained in silicone, which can help the silicone to cure quickly after being heated; however, platinum catalyst is easily deactivated or poisoned by some chemical components, which makes the curing reaction of the silicone inhibited ( Inhibition), resulting in the silicone being unable to cure, or only partially cured. Chemical components that may deactivate or poison platinum catalysts include: sulfur, sulfurides, thio compounds, tin, fatty acid tin salts, phosphorus, phosphines, phosphites, arsenic, arsines, antimony, stibines, selenium, selenide, tellurium, telluride, amines , Armides, ethanolamine, N-methylethanolamine, triethanolamine, chelates, EDTA (ethylenediaminetetraacetic acid), NTA (nitriloacetic acid), ethanol, methanol, etc. Therefore, when the platinum catalyst silicon is used as the first polymer material 211, the problem of passivation or poisoning of the platinum catalyst should be considered.

The second PL layer 23 can generate a higher energy level light (such as green light) when excited by the first light, which can include a second polymer material 231 and a higher excitation energy level quantum dot material (such as green quantum). (Point material, hereinafter referred to as green QD material) 232. In order to simplify the description, the following will take the green QD material 232 and the green light emitted by it as an example for technical description. The green QD material 232 can be uniformly mixed and glued (fixed) in the second polymer material 231. The green QD material 232 can generate green light after being irradiated with the first light of a higher energy level. The green QD material 232 may include, but is not limited to, cadmium selenide (CdSe), indium phosphide (InP), zinc sulfide (ZnS), zinc selenide (ZnSe), or zinc telluride (ZnTe). . In addition, the quantum dot crystal structure of the green QD material 232 generally includes a core and a protective shell.

Because the red light generated by the aforementioned fluoride fluorescent material when excited by the first light has a narrower FWHM, it can be comparable to the high-purity red light generated by the quantum dot material. Therefore, in the application of the backlight source of the wide color gamut display, a preferred embodiment of the light-emitting device 1 is: the LED chip 10 is an LED chip that emits blue light, and the fluorescent material contained in the first PL layer 21 The high-purity red-fluoride fluoride material and the second PL layer 23 include a green quantum dot material capable of emitting higher-purity green light.

The second polymer material 231 may include, but is not limited to, a resin material or a silicon material, which has good light transmittance. Since the quantum dot material is susceptible to oxidation at high temperatures, it is not suitable to use a thermal curing adhesive. Therefore, the second polymer material 231 is preferably an ultraviolet curing adhesive, and the second polymer material 231 is exposed to ultraviolet light at normal temperature. It can be cured without curing at high temperature like heat curing glue. In this way, when the second polymer material 231 is cured, it will not experience high temperature and the efficiency of the green QD material 232 will be reduced.

Ultraviolet curing adhesives usually contain chemical components that passivate or poison the platinum catalyst, making the silicone adhesives that need to be thermally cured incapable of curing. Therefore, the second polymer material 231 composed of the ultraviolet curable adhesive cannot be in contact with the first polymer material 211 composed of the thermosetting adhesive during the manufacturing process, otherwise the first polymer material 211 cannot be cured.

In this embodiment, the optically transparent isolation layer 22 can isolate the first PL layer 21 and the second PL layer 23, and the chemical components in the second polymer material 231 that can passivate or poison the platinum catalyst cannot diffuse to the first height. The molecular material 211 enables the first polymer material 211 to be completely cured. It can be known from this that the optically transparent isolation layer 22 can improve the incompatibility of the first polymer material 211 and the second polymer material 231 with each other in terms of material characteristics or curing process. Specifically, the light transparent isolation layer 22 is used to isolate the first PL layer 21 and the second PL layer 23 to avoid contact between the two, and to make the second PL layer 23 farther away. The LED chip 10 reduces the influence of the thermal energy of the LED chip 10 on the second PL layer 23. The light-transparent isolation layer 22 may include, but is not limited to, a transparent inorganic material (such as quartz or glass) or a polymer material with good light transmittance. In addition, the optically transparent isolation layer 22 preferably does not include a chemical component that can passivate or poison the platinum catalyst, so it can contact the first polymer material 211.

In addition, the light-transparent moisture barrier layer 24 of the light-emitting device 1 is used to block the passage of water and gas to protect the quantum dot material of the second PL layer 23 from oxidation. The light-transparent moisture barrier layer 24 may include, but is not limited to, a transparent inorganic material (such as quartz or glass) or a polymer material having a good light transmittance; if it is a polymer material, a low water vapor permeability is selected. For example, it has a water vapor permeability of not more than 20 g / (m ² day) when the thickness is 1 mm. The light transparent insulation layer 22 can also be selected to have a low water vapor permeability. For example, when the thickness is 1 mm, it has a water vapor permeability of not more than 20g / (m ² day). Therefore, the light transparent moisture barrier layer 24 and light The transparent isolation layer 22 sandwiches the second PL layer 23 of the internal dot material, making it difficult for water or oxygen in the external environment to contact the green QD material 232 in the second PL layer 23, reducing or avoiding water vapor Or oxygen penetrates into the green QD material 232 from above or below.

The moisture blocking reflection structure (hereinafter referred to as a reflection structure) 30 can reflect the light emitted from the side of the light-emitting device and guide the light to the front. Specifically, the reflective structure 30 covers the side surface 203 of the PL structure 20 and the elevation surface 103 of the LED chip 10, but does not cover the top surface 201 of the PL structure 20, so it can reflect the light emitted from the elevation surface 103 and the side surface 203, so that The light is emitted toward the top surface 201 of the PL structure 20. The reflective structure 30 is not lower than the lower surface 102 of the LED chip 10, and does not cover the lower surface 102 and the electrode group 104. The top surface 301 of the reflective structure 30 can be substantially flush with the top surface 201 of the PL structure 20. Since the light-emitting device 1 is a wafer-level packaged light-emitting device, it can be directly bonded to a printed circuit board or other application substrate, so it has lower heat. To reduce the operating temperature of the light-emitting device, so the bottom of the reflective structure 30 The surface 302 cannot be lower than the height of the electrode surface 102 to avoid poor bonding between the electrode group 104 and the substrate pad. Preferably, the bottom surface 302 of the reflective structure 30 can be substantially flush with the electrode surface 102 of the LED chip 10. In addition, the reflective structure 30 may also cover a portion of the bottom surface 202 of the PL structure 20 beyond the upper surface 101 of the LED chip 10. Although the second PL layer 23 of the internal sub-dot material is disposed between the light transparent moisture barrier layer 24 and the light transparent isolation layer 22, it is difficult for water and gas in the external environment to contact the green QD in the second PL layer 23. Material 232, but moisture can still penetrate through the sides of the second PL layer 23. Another effect of the reflective structure 30 of the light-emitting device is to prevent the penetration of water vapor in the environment, to reduce or avoid the possibility of water vapor or oxygen from contacting the green QD material 232 from the side; therefore, the reflective structure 30 is blocked by moisture. The coating of the light transparent moisture barrier layer 24 and the light transparent isolation layer 22 can further provide the green QD material 232 moisture barrier protection to reduce the occurrence of photo-oxidation.

In order for the reflective structure 30 to have the above-mentioned characteristics, it may preferably include a third polymer material 31 and one light-scattering particle 32 mixed with the third high-scoring material 31; Those with low water vapor permeability (for example, no more than 20g / m ² / day when the thickness is 1 mm) may include a resin material or a silicone material to make it difficult for water vapor to pass through; the light-scattering particles 32 may specifically be Titanium dioxide (TiO ₂ ), boron nitride (BN), silicon dioxide (SiO ₂ ), or aluminum oxide (Al ₂ O ₃ ), etc., and a weight percentage of the reflective structure 30 is not less than 20%, and Achieve good reflection effect.

Please refer to FIG. 2A, and then further explain how to use the first PL layer 21 to reduce the light intensity of the first light to the light intensity that the green QD material 232 can withstand, so as to avoid photo-oxidation of the quantum dot material. Specifically, the first light emitted by the LED chip 10 is blue light B as an example. The initial light intensity is L0. When blue light B passes through the first PL layer 21, a part (ie, the first part) will be Converted into red light R. The remaining part of Blu-ray B that has not been converted (i.e. the second part The light intensity is L1, which is less than the initial light intensity L0. The remaining second portion of the blue light B then partially excites the green QD material 232 and is then converted into green light G (ie, a portion of the second portion is converted into green light G again). Therefore, the light finally emitted from the top surface 201 of the PL structure 20 (ie, the light-emitting surface of the light-emitting device 1) includes blue light B, red light R, and green light G, and can be mixed to form a white light.

Therefore, the green QD material 232 in the light-emitting device 1 disclosed in the present invention will be irradiated by blue light B and red light R. Since the energy level of red light R is not sufficient to excite the green QD material 232 to generate green light G, it will not The green QD material 232 generates free electrons and holes, and the free electrons will electro-activate the quantum dot material to cause photo-oxidation. Therefore, the green QD material 232 is not prone to photo-oxidation when irradiated with red light R.

Since the green QD material 232 will still generate a large number of free electrons under the irradiation of blue light B and cause photo-oxidation of the quantum dot material, the light emitting device 1 disclosed in the present invention can significantly reduce the intensity of blue light B irradiated to the green QD material 232. Specifically, the initial light intensity of the blue light B provided by the LED chip 10 is L0. For convenience of explanation, it is divided into the first part and the second part; after passing the first PL layer 21, the blue light of the first part B is converted into red light R and unconverted second blue light B. The initial blue light intensity L0 will be reduced to the blue light intensity L1 corresponding to the second part. This blue light intensity L1 is not greater than the light that the green QD material 232 can withstand. Intensity, under the light intensity L1 of blue light B, the green QD material 232 is still not prone to photo-oxidation, so that the green QD material 232 has a more stable luminous spectrum and luminous efficiency, and has a longer service life.

The blue light B (second part) that has not been converted after passing through the first PL layer 21 can be measured in the following manner: before the second PL layer 23 is set (or the second PL layer 23 is moved Except), the LED chip 10 is driven to emit blue light B, and then the intensity value of the blue light B is measured from above the first PL layer 21. In addition, if it is illuminated by blue light B with light intensity L1 for a period of time, if green The light converted by the QD material 232 has no significant intensity attenuation (for example, no greater than 20% or no greater than 10% intensity attenuation) or no significant wavelength shift (for example, no greater than 10 nm or less than 5 nm). Peak wavelength shift), it should be inferred that the light intensity L1 of the blue light B is not greater than the light intensity that the green QD material 232 can withstand.

Depending on the structure and material of the green QD material 232, the light intensity of the first light that it can withstand will also be different; for example, the blue light intensity that the currently known green QD material 232 can withstand is not greater than 10 W / cm ² More than 5 W / cm ² or not more than 2 W / cm ² . As the development of science and technology will continue to improve the structure of quantum dot materials, it can be expected that the upper limit of the light intensity that the quantum dot materials can withstand, such as more than 10 W / cm ² .

The upper limit of the light intensity of the incident light used to excite the quantum dot material can usually be provided by its manufacturer or supplier, and can also be known through experimental testing. For example, irradiate blue light B (or other high-energy first light) with different light intensities onto the green QD material 232, and then measure the changes in the green light intensity and peak wavelength converted by the green QD material 232 over a period of time; By observing whether the intensity of the converted light is significantly attenuated (such as an intensity attenuation of not more than 20% or not more than 10%), the wavelength is significantly shifted (such as not more than 10 nm or not more than 5 nm). Peak wavelength shift), the light intensity of the blue light B that the green QD material 232 can withstand under long-term operation can be measured.

FIG. 2B is a measurement result of light emission spectrum of a preferred embodiment of the light emitting device 1. The LED chip 10 in this example can emit a blue light B with a peak wavelength of 443 nanometers, and use a KSF red fluorescent lamp with a peak wavelength of 630 nanometers. An optical material is used as the lower excitation energy level fluorescent material of the first PL layer 21, and an InP green quantum dot material having a peak wavelength of 540 nm is used as the higher excitation energy level quantum dot material of the second PL layer 23. KSF closer to LED chip 10 under blue light excitation The fluorescent material can first absorb a part of the blue light B emitted from the LED chip 10, and convert and emit a red light R having a narrow half-width, and the unconverted blue light B and red light R are then transmitted to the second PL layer 23, Among them, the unconverted blue light B is absorbed by the green quantum dot material of the second PL layer 23 and converted into a green light G with a half-height of 39 nanometers, which is shown as a green light spectrum G in FIG. 2B. The blue light spectrum B shown in FIG. 2B is part of the blue light B that is not converted by the second PL layer 23, and the red light R is not enough to excite the green quantum dot material of the second PL layer 23 because of its low energy level, so it can Most of the output light-emitting devices are outside the red light spectrum R shown in FIG. 2B. Since the first PL layer 21 has converted about 1/3 of the blue light B intensity into red light R, it can effectively reduce the light intensity of about 1/3 of the blue light B irradiated to the green quantum dot material, making it less likely to cause photooxidation. Has a longer life. Since the light-emitting device 1 has red, green and blue spectrums with high color purity (narrow half-width-to-height), it is very suitable for a backlight light source for a wide color gamut liquid crystal display.

Please refer to FIG. 2C. The following will further explain how the first PL layer 21 increases the light extraction rate of the green light G. A part of the green light G1 converted from the green QD material 232 will be output to the outside of the PL structure 20, but the other part of the green light G2 will be reversely advanced toward the LED chip 10; if the red of the first PL layer 21 is red The fluorescent material 212 selects a specific kind of fluoride fluorescent material, and will not be excited by light having a wavelength greater than about 500 nm. Therefore, the green light G2 scattered toward the wafer 10 will not be absorbed and converted by the red fluorescent material 212. In this way, the green light G2 traveling in the opposite direction toward the LED chip 10 can be effectively scattered outward by the red fluorescent material 212, and the green light is output to the outside of the light emitting device 1. Therefore, the light extraction efficiency of the green light G (G1, G2) can be effectively increased.

Please refer to FIG. 1C. In another embodiment, the second PL layer 23 may further include a light scattering particle 233 mixed with the second polymer material 231. The quantum dot material is nano-sized particles, and the first light is easy to penetrate without exciting the quantum dot material, so the light scattering property is small. The particles 233 are used to scatter the first light in the second PL layer, and increase the probability that the first light excites the green QD material 232. In other words, the light-scattering particles 233 can increase the total light path of the first light passing through the second PL layer 23 to increase the proportion of the first light being converted into green light. In addition, the weight percentage of the light-scattering particles 233 in the second PL layer 23 is preferably not more than 20%, not more than 15%, or not more than 10% to provide a suitable light transmittance and avoid excessive blocking of the first light. .

In yet another embodiment, the LED chip 10 is a dark blue LED chip, a purple LED chip, or an ultraviolet LED chip, and the first light emitted by the LED chip 10 is dark blue, violet, or ultraviolet light. At this time, the second PL layer 23 may further include another quantum dot material 234 having a higher excitation energy level. For example, the second PL layer 23 may be a blue quantum dot material 234, which may be mixed in the second polymer material 231 or may be mixed. In another polymer material different from the second polymer material 231 (not shown). Dark blue light or ultraviolet light can be converted into blue light by the blue quantum dot material 234, so that the light generated by the light emitting device 1 can include blue light, red light, and green light.

The above is a description of the technical content of the light-emitting device 1, and then the technical content of other embodiments according to the present invention will be described, and the technical content of each embodiment should be mutually referable, so the same parts will be omitted or simplified. In addition, the technical contents of the embodiments should be applicable to each other and combined.

Please refer to FIG. 3, which is a schematic diagram of a light emitting device 2 according to a second preferred embodiment of the present invention. The PL structure 20 of the light-emitting device 2 further includes a light transparent thermally conductive layer 25; the light transparent thermally conductive layer 25 may be disposed between the second PL layer 23 and the light transparent moisture barrier layer 24, and / or the second PL layer 23 In other words, the top surface and / or the bottom surface of the second PL layer 23 may be disposed to cover a light transparent thermally conductive layer 25.

The light transparent thermally conductive layer 25 has a good thermal conductivity (ie, low thermal resistance), and is larger than that of the light transparent moisture barrier layer 24 or the light transparent isolation layer 22; in addition, the light transparent thermally conductive layer 25 also needs to have good light transmittance. Therefore, the light transparent thermally conductive layer 25 may include, but is not limited to, a thin film metal, a grid-like metal, a transparent conductive oxide, or graphene, etc., where the transparent conductive oxide may be, for example, indium tin oxide (Indium Tin Oxide). , ITO), its light transmittance can be greater than 90%, and its thermal conductivity (at 25 ° C) is about 10 ~ 12W / mK; the thermal conductivity of graphene is as high as 5300W / mK. The light-transparent heat-conducting layer 25 can quickly transfer or disperse the thermal energy generated by the second PL layer 23 during light conversion, so as to reduce the operating temperature of the green QD material 232, and further reduce the influence of the thermal energy on the green QD material 232.

The reflective structure 30 may also optionally include a thermally conductive material (not shown), mixed with the third polymer material 31, so that the thermal conductivity of the reflective structure 30 is not less than that of the light transparent moisture barrier layer 24 or the light transparent isolation layer 22 Thermal conductivity. In this way, the thermal energy of the second PL layer 23 can also be effectively transmitted outward through the reflective structure 30, reducing the effect of high temperature on the green QD material 232. The thermally conductive material may include graphene, a ceramic material, or the like. The ceramic material may be aluminum nitride (with a thermal conductivity of about 285 W / mK) or alumina. The thermally conductive material may also include a metal material, preferably it can be prevented from contacting the LED chip 10, for example, the reflective structure 30 containing the metal thermally conductive material covers the light guiding structure 40 (shown in FIG. 4B) described later, in other words, The reflective structure 30 indirectly covers the facade 103 of the LED chip 10.

Please refer to FIG. 4A, which is a schematic diagram of a light emitting device 3 according to a third preferred embodiment of the present invention. The PL structure 20 of the light-emitting device 3 further includes a light transparent separation layer 26 disposed on the upper surface 101 of the LED chip 10; the first PL layer 21 is provided on the light transparent separation layer 26 and does not directly cover and contact the LED chip 10. In this way, the second PL layer 23 can be further away from the hot LED chip 10 to further reduce the influence of the high-temperature LED chip 10 on the green QD material 232. The light-transparent separation layer 26 may include, but is not limited to, a transparent inorganic material (such as quartz or glass) or a high-molecular material (such as silicone). If it is a high-molecular material, it may be preferable to have a low water vapor permeability. In order to reduce the possibility of water vapor and oxygen penetrating inside the light-emitting device.

Please refer to FIG. 4B. In another aspect of the third preferred embodiment of the present invention, the light emitting device 3 further includes a light guiding structure 40. The light guiding structure 40 may include a polymer material (such as those with good light transmittance such as silicone, epoxy, rubber, etc.), and may cover the facade 103 of the LED chip 10 and then be covered by the reflective structure 30. More specifically, the light guiding structure 40 may include a top surface 401 and an inclined side surface 402. The top surface 401 may be flush with the upper surface 101 of the LED chip 10, and the inclined side surface 402 is opposite to the vertical surface 103 of the LED chip 10. Is inclined; the inclined side surface 402 may be a concave curved surface (as shown in the figure), or a flat or convex curved surface (not shown in the figure). In addition, the inclined side surface 402 is also directly covered by the reflective structure 30, so the reflective structure 30 has an inner inclined surface (or an inner inclined side surface) corresponding to the inclined side surface 402. When the inclined side surface 402 is directly covered by the reflective structure 30, the vertical surface 103 of the LED chip 10 is indirectly covered by the reflective structure 30.

In addition, since the wafer-level packaged light-emitting device does not require a packaging bracket, the light-emitting device disclosed by the present invention can have a larger light-emitting area under the same packaging volume, that is, the area of the PL structure 20 can be larger. When the blue light B emitted from the wafer 10 is irradiated to the large-area PL structure 20, the intensity of the blue light per unit area of the quantum dot material irradiated into the PL structure 20 can be effectively reduced, so the photo-oxidation phenomenon of the quantum dot material can be further reduced. The light guide structure 40 cooperates with the reflection structure 30 to effectively reflect the first light emitted from the side of the LED chip 10 into the PL structure 20 so that the first light illuminates the PL structure 20 more uniformly and reduces the blue light intensity per unit area. To reduce the photo-oxidation phenomenon of the quantum dot material to increase its service life; the technical content of the light guide structure 40 in conjunction with the reflective structure 30 can be further referred to the Taiwan Patent Application No. 106103239 previously applied by the applicant.

Please refer to FIG. 5A to FIG. 5I, and then the preferred embodiment according to the present invention will be described. The manufacturing method of the light-emitting device of this embodiment can manufacture the same or similar light-emitting devices 1 to 3 of the above-mentioned embodiments, so the technical content of the manufacturing method and the technical content of the light-emitting devices 1 to 3 can refer to each other and be applied.

As shown in FIG. 5A, the light-transparent moisture barrier layer 24 is first provided or formed, and then directly applied to the light-transparent moisture barrier layer 24 by spraying, spin coating, or printing. A second PL layer 23 is formed thereon; that is, an uncured second polymer material 231 and a green QD material 232 are mixed first, and then formed on the light-transparent moisture barrier layer 24 through the above-mentioned method. The material 231 is cured, that is, the second PL layer 23 is formed. If the second polymer material 231 is a heat-curable silicone, it needs to be thermally cured in an inert gas or a vacuum environment. In addition, the second PL layer 23 may be formed separately and then adhered to the light-transparent moisture barrier layer 24.

As shown in FIG. 5B, a light-transparent isolation layer 22 is directly formed on the second PL layer 23, for example, spray coating, spin coating, or printing can be used, or the light-transparent isolation layer 22 can be attached to the second PL 层 23。 PL layer 23. As shown in FIG. 5C, the first PL layer 21 is then directly formed on the light-transparent isolation layer 22, for example, by spray coating, spin coating, or printing, or by US Patent Application Publication No. US2010 / 0119839 ( Corresponds to the technology disclosed in the Taiwan Patent of Certificate No. I508331); or, after the first PL layer 21 is separately formed, it is then bonded to the light-transparent isolation layer 22.

In this way, the PL structures 20 of the plurality of light-emitting devices 1 can be fabricated and still be integrally connected to each other. In addition, in the step shown in FIG. 5A, a light transparent thermally conductive layer 25 may be selectively formed before and / or after the formation of the second PL layer 23 to fabricate the PL structures 20 of the plurality of light emitting devices 2. As shown in FIG. 5D, a light transparent separation layer 26 may be optionally formed on the first PL layer 21 to fabricate a PL structure 20 of a plurality of light emitting devices 3.

As shown in FIG. 5E, after the PL structure 20 is fabricated, the plurality of LED chips 10 are then inverted so that the upper surface 101 faces downward (the lower surface 102 faces upward) and faces the bottom surface 202 of the PL structure 20. The wafer 10 is adhered to the inner layer of the PL structure 20 (that is, the light transparent separation layer 26 or the first PL layer 21). After the LED wafer 10 is bonded, a light guide structure 40 can be optionally formed on the first PL layer 21 or the light transparent separation layer 26. For the specific formation of the light guide structure 40, please refer to the application number applied by the applicant. 106103239 Taiwan patent application.

As shown in FIG. 5F, after the bonding of the LED chip 10 is completed, the PL structures 20 integrally connected are cut to separate them; each PL structure 20 is bonded to one of the LED chips 10 to form a light-emitting structure. As shown in FIG. 5G, the light-emitting structures are then arranged on a release material 900 to form an array of light-emitting structures; during the arrangement, the top surface 201 of the PL structure 20 can be selected to be attached to the release material 900 ( (As shown in the figure), or the lower surface 102 of the LED chip 10 is adhered to the release material 900, and the electrode group 104 is embedded in the release material 900 (not shown).

As shown in FIG. 5H, a reflective structure 30 is then formed between the release material 900 and the light emitting structure to cover the side surface 203 of the PL structure 20 and the inclined side surface 402 of the light guide structure 40 (indirectly covering the LED chip 10). Façade 103), but does not cover the lower surface 102 of the LED chip 10; the formation of the reflective structure 30 may be by molding or dispensing. After the reflection structure 30 is formed, a plurality of light emitting devices 3 (or other types of light emitting devices) can be obtained, and these light emitting devices 3 are connected to each other. As shown in FIG. 5I, finally, a cutting step is taken to separate the connected light-emitting devices 3 to obtain the light-emitting devices 3 separated from each other; wherein the release material 900 and the light-emitting device 3 can be separated before or after cutting. Separation.

Please refer to FIG. 5C or FIG. 5D. After the integrally connected PL structure 20 is produced, the cutting step can also be directly performed to separate it into a plurality of PL structures 20; The structure 20 is bonded to the LED chip 10, and then a reflective structure 30 is formed to cover the two, and the production of the light emitting device 3 (or other types of light emitting devices) can also be completed.

Please refer to FIG. 6A to FIG. 6D. The PL structure 20 can also be fabricated in the following manner. As shown in FIG. 6A, a light transparent moisture barrier layer 24 is first provided or formed, and then a second PL layer 23 is formed on the light transparent moisture barrier layer 24. As shown in FIG. 6B, a light transparent isolation layer 22 is then provided or formed, and a first PL layer 21 is formed on the light transparent isolation layer 22; neither the light transparent isolation layer 22 nor the first PL layer 21 is the same as the first 5B is sequentially formed on the second PL layer 23.

In other words, the combination of the light transparent moisture barrier layer 24 and the second PL layer 23, and the combination of the light transparent isolation layer 22 and the first PL layer 21 are separately manufactured, and the manufacturing processes of the two will not affect each other. Therefore, if the first polymer material 211 of the first PL layer 21 is a thermosetting adhesive, the high temperature at which it is thermally cured will not affect the green QD material 232 of the second PL layer 23, so the efficiency of the green QD material 232 is not good. It will be attenuated by the thermal curing process of the first PL layer 21.

As shown in FIG. 6C, the LED chip 10 is then attached to the first PL layer 21, and optionally, a light transparent separation layer 26 and / or a light guiding structure 40 are formed on the first PL layer 21. As shown in FIG. 6D, the light-transparent isolation layer 22 and the second PL layer 23 are adhered to each other to manufacture the PL structure 20 as shown in FIG. 5E. After that, steps as shown in FIG. 5F to FIG. 5I may be taken to obtain the light emitting device 3 or other light emitting devices separated from each other.

To sum up, the light-emitting device provided by the preferred embodiment of the present invention can effectively improve the oxidation phenomenon of the quantum dot material, and can reduce or prevent water vapor and oxygen in the outside air from contacting the quantum dot material; it can also effectively avoid The polymer materials used to fix quantum dot materials and the polymer materials used to fix fluorescent materials are incompatible with each other; they can also effectively improve the thermal attenuation of quantum dot materials and reduce the quantum dot materials. Withstand temperature and increase Light extraction efficiency of light emitting devices. The manufacturing method of the light-emitting device can manufacture various light-emitting devices having the above-mentioned effects, and the quantum dot material can not be subjected to high temperature during the manufacturing process.

The above embodiments are only used to exemplify the implementation aspects of the present invention, and to explain the technical features of the present invention, and are not intended to limit the protection scope of the present invention. Any change or equivalence arrangement that can be easily accomplished by those skilled in the art belongs to the scope claimed by the present invention, and the scope of protection of the rights of the present invention shall be subject to the scope of patent application.

Claims (24)

A light-emitting device includes: a flip-chip LED chip for providing a first light, the first light being a blue light, a dark blue light, a purple light or an ultraviolet light; a photoluminescent structure disposed on the cover An upper surface of one of the crystalline LED wafers includes a first photoluminescent layer, a light transparent isolation layer, a second photoluminescent layer, and a light transparent moisture barrier layer. The light transparent isolation layer is disposed on the On the first photoluminescence layer, the second photoluminescence layer is disposed on the phototransparent isolation layer, and the phototransparent moisture barrier layer is disposed on the second photoluminescence layer, wherein the first photoluminescence layer The light-emitting layer includes a first polymer material and a fluorescent material with a lower excitation energy level mixed in the first polymer material, and the second photoluminescent layer includes a second polymer material and the second polymer material is mixed with the first polymer material. One of the second polymer materials with a higher excitation energy level quantum dot material; and a moisture blocking reflection structure covering one side of the photoluminescence structure and one facade of the flip-chip LED chip, and not low On an electrode surface of the flip-chip LED chip; wherein, the The lower excitation energy level fluorescent material of a photoluminescent layer is used to convert a part of the first light into a longer wavelength visible light, so that the unconverted part of the first The light intensity of the light is not greater than the light intensity that the higher quantum dot material can withstand. The light-emitting device according to claim 1, wherein the fluorescent material with a lower excitation energy level comprises a red fluorescent material, and the quantum dot material with a higher excitation energy level comprises a green quantum dot material. The light-emitting device according to claim 2, wherein the light intensity of the first ray that the green quantum dot material can withstand is not more than 10 W / cm ² . The light-emitting device according to claim 2, wherein the photoluminescent structure further includes a light transparent thermally conductive layer disposed between the second photoluminescent layer and the light transparent moisture barrier layer, And / or disposed between the second photoluminescent layer and the light transparent isolation layer; wherein the thermal conductivity of the light transparent thermally conductive layer is greater than the thermal conductivity of the light transparent moisture barrier layer or the light transparent isolation layer. The light-emitting device according to claim 4, wherein the light transparent thermally conductive layer comprises a thin film metal, a grid-like metal, a transparent conductive oxide, or a graphene. The light-emitting device according to any one of claims 2 to 5, wherein the photoluminescent structure further includes a light transparent separation layer, and the first photoluminescent layer is disposed on the light transparent separation layer. The light-emitting device according to any one of claims 2 to 5, further comprising a light-guiding structure covering the facade of the flip-chip LED chip, and the light-guiding structure includes an inclined side, The inclined side surface is inclined relative to the vertical surface of the flip-chip LED chip, and is covered by the moisture blocking reflection structure. The light-emitting device according to any one of claims 2 to 5, wherein the first polymer material is a thermosetting glue and the second polymer material is an ultraviolet curing glue. The light emitting device according to any one of claims 2 to 5, wherein each of the light transparent isolation layer and the light transparent moisture barrier layer includes a transparent inorganic material. The light-emitting device according to any one of claims 2 to 5, wherein each of the light-transparent isolation layer and the light-transparent moisture barrier layer comprises a polymer material, which has a thickness of not more than 20g / (m ² day) water vapor permeability (WVTR). The light-emitting device according to any one of claims 2 to 5, wherein the moisture blocking reflection structure includes a third polymer material and one light-scattering particle mixed with the third high-scoring material. The light-emitting device according to claim 11, wherein the third polymer material has a water vapor permeability of not more than 20 g / (m ² day) when the thickness is 1 mm. The light-emitting device according to any one of claims 2 to 5, wherein a thermal conductivity of the moisture-barrier reflective structure is not less than a thermal conductivity of the optically transparent isolation layer or the optically transparent moisture-barrier layer. The light emitting device according to any one of claims 2 to 5, wherein the second photoluminescent layer further comprises a light scattering particle, and the light scattering particle is mixed in the second polymer material. The light-emitting device according to any one of claims 2 to 5, wherein the red fluorescent material comprises a fluoride fluorescent material or a nitride fluorescent material. The light-emitting device according to claim 15, wherein the fluoride fluorescent material includes at least one of the following: (A) A ₂ [MF ₆ ]: Mn ⁴⁺ , wherein A is selected from Li, Na, K, and Rb , Cs, NH ₄ and combinations thereof, M is selected from Ge, Si, Sn, Ti, Zr and combinations thereof; (B) E ₂ [MF ₆ ]: Mn ⁴⁺ , wherein E is selected from Mg, Ca, Sr, Ba , Zn and combinations thereof, and M is selected from Ge, Si, Sn, Ti, Zr and combinations thereof; (C) Ba _0.65 Zr _0.35 F _2.70 : Mn ⁴⁺ ; or (D) A ₃ [ZrF ₇ ]: Mn ⁴⁺ Where A is selected from Li, Na, K, Rb, Cs, NH ₄ and combinations thereof. The light-emitting device according to claim 15, wherein the fluoride fluorescent material includes at least one of the following: (xa) MgO. (A / 2) Sc ₂ O ₃ .yMgF ₂ .cCaF _2. (1-b ) GeO _2. (B / 2) Mt ₂ O ₃ : zMn ⁴⁺ ; Among them, 2.0 x 4.0, 0 <y <1.5, 0 <z <0.05, 0 a <0.5, 0 <b <0.5, 0 c <1.5, y + c <1.5, and Mt is selected from at least one of Al, Ga, and In. The light emitting device according to any one of claims 2 to 5, wherein the second photoluminescent layer further comprises a blue quantum dot material. A method for manufacturing a light-emitting device includes: bonding a photoluminescent structure to a flip-chip LED chip; and forming a moisture blocking reflection structure to cover one side of the photo-luminescent structure and the flip-chip type A facade of an LED chip; wherein the photoluminescent structure includes a first photoluminescent layer, a light transparent isolation layer, a second photoluminescent layer, and a light transparent moisture barrier layer, the light transparent isolation layer Is disposed on the first photoluminescent layer, the second photoluminescent layer is disposed on the light transparent isolation layer, and the light transparent moisture barrier layer is disposed on the second photoluminescent layer, the first light An electroluminescent layer covers an upper surface of one of the flip-chip LED wafers. The first photoluminescent layer includes a first polymer material and a lower excitation energy level fluorescent material mixed in the first polymer material. And the second photoluminescent layer includes a second polymer material and a quantum dot material of a higher excitation energy level mixed in the second polymer material, the moisture blocking reflection structure is not lower than the flip-chip The following table shows one electrode of the LED chip; Type LED chip is used to provide a first light, the first light is a blue light, a deep blue light, a violet light or an ultraviolet light, and the lower excitation energy level fluorescent material of the first photoluminescent layer is used In order to convert a part of the first light to a longer wavelength of visible light, the light intensity of the unconverted part of the first light is not greater than that of the quantum dot material with a higher excitation energy level. Withstand the intensity of light. The method for manufacturing a light emitting device according to claim 19, further comprising: forming the photoluminescent structure, comprising: providing the light transparent moisture barrier layer; and forming the second photoluminescent layer on the light transparent moisture barrier Layer; forming the light transparent isolation layer on the second photoluminescent layer; and forming the first photoluminescent layer on the light transparent isolation layer. The method for manufacturing a light-emitting device according to claim 19, further comprising: forming the photoluminescent structure, including: providing the light transparent moisture barrier layer, and forming the second photoluminescent layer on the light transparent moisture. On the barrier layer; providing the light transparent isolating layer and forming the first photoluminescent layer on the light transparent isolating layer; and adhering the light transparent isolating layer and the second photoluminescent layer. The method for manufacturing a light emitting device according to claim 19, wherein the photoluminescent structure further includes a light transparent thermally conductive layer formed on the second photoluminescent layer and the light transparent moisture barrier layer Between, and / or formed between the second photoluminescent layer and the light transparent moisture barrier layer; wherein the thermal conductivity of the light transparent thermally conductive layer is greater than that of the light transparent isolation layer or the light transparent moisture barrier Thermal conductivity. The method for manufacturing a light-emitting device according to any one of claims 19 to 22, wherein the photoluminescent structure further includes a light transparent separation layer formed on the first photoluminescent layer; wherein The light transparent separation layer covers the upper surface of the flip-chip LED chip. The method for manufacturing a light emitting device according to any one of claims 19 to 22, further comprising forming a light guiding structure formed on the first photoluminescent layer to cover the flip-chip LED. The vertical surface of the wafer, wherein the light guiding structure includes an inclined side surface, the inclined side surface is inclined relative to the vertical surface of the flip-chip LED chip; and when the moisture blocking reflection structure is formed, the wet The air-blocking reflection structure covers the inclined side of the light guiding structure.