Fluorescent film, LED lamp and fluorescent film preparation method

Abstract

The invention discloses a fluorescent film, an LED lamp and a preparation method of the fluorescent film, and the preparation method of the fluorescent film comprises the following steps: dividing fluorescent glue into two groups, and coating a carrier with the first group of fluorescent glue to form a first fluorescent film layer; wherein the carrier is placed on the heating carrying table, and the temperature of the heating carrying table is 70-90 DEG C; wherein the fluorescent glue is prepared from fluorescent powder, packaging glue and a diluent; raising the temperature of the heating platform deck, stabilizing the temperature to 100-130 DEG C, and coating the first fluorescent film layer with a second group of fluorescent glue to form a second fluorescent film layer; the carrier coated with the first fluorescent film layer and the second fluorescent film layer is placed in an oven at the temperature of 100-150 DEG C to be baked and cured, the carrier is taken out and cooled to the room temperature, the fluorescent film is peeled off from the carrier, and the fluorescent film is obtained. The fluorescent film prepared by the preparation method of the fluorescent film has good light emitting uniformity and adhesion and relatively low material adhesion.

Description

Technical Field

[0001] The present invention belongs to the technical field of lamps, and particularly relates to a fluorescent film, an LED lamp and a preparation method of the fluorescent film. Background Art

[0002] As a new type of high-efficiency solid-state light source, the LED lamp has attracted extensive attention from experts and scholars in the field with its remarkable advantages such as energy conservation, high efficiency, environmental protection and pollution-free, and long service life. As a new generation of green lighting technology, it is one of the new industries vigorously promoted and focused on research by countries around the world, and is regarded as the fourth-generation lighting source.

[0003] At present, the traditional packaging method of LED lamps is to coat a mixture of phosphor and silica gel on the surface of the LED chip. The specific implementation process is as follows: Weigh a certain amount of silica gel or epoxy resin and phosphor, mix the phosphor and silica gel or epoxy resin evenly in a suitable proportion, after degassing and vacuum pumping, use a dispensing machine to drop the phosphor glue on the surface of the LED chip, and finally place it in an oven to cure it, which is usually called dispensing. However, there are still the following problems in the current industrialized LED packaging process: First, the concentration of the phosphor is inconsistent. When the phosphor and silica gel mixture is vertically dropped on the LED chip, during the dispensing process, the phosphor will precipitate, resulting in inconsistent light colors of the LED, and it is necessary to perform spectral separation again, increasing the cost of the factory; Second, the yellow ring effect of the LED. For a single LED package, the phosphor glue is approximately spherical and drops from the dispensing head onto the chip. After the fluorescent glue naturally levels and cures, the surface is convex, thick in the middle and thin around, and the phosphor is unevenly distributed. After the LED is lit, the yellow ring effect will appear; Third, LED heat dissipation and phosphor heat aging. After the LED works for a long time, a large amount of heat is generated. In the dispensing method, the phosphor glue wraps the chip, making it difficult for the heat to dissipate, resulting in a reduced service life of the chip. At the same time, it will also cause the phosphor to age due to heat and light decay.

[0004] To solve the above problems existing in the dispensing method, remote packaging materials such as fluorescent films, fluorescent glasses, and fluorescent ceramics have emerged. The fluorescent film not only maintains the good characteristics of the phosphor but also has the characteristics of being soft and arbitrarily bendable. Using the fluorescent film for LED packaging can significantly solve the problems existing in the above-mentioned dispensing. In the existing preparation methods of fluorescent films, usually, a viscous fluorescent glue is obtained by mixing phosphors and encapsulation glue, and the fluorescent glue is directly coated on a thin film substrate. After coating, the film is placed in a well-ventilated environment to dry naturally or dried and cured using a drying device. The fluorescent film prepared by this preparation method usually has a double-sided smooth structure, which can ensure the characteristic of high light output uniformity. However, due to problems such as poor adhesion, unfavorable transportation operations, and sticking materials in the smooth structure, during the transportation of the fluorescent film, it needs to be carried on a carrier film for transportation to maintain the integrity of the fluorescent film. However, during the transfer process of the fluorescent film, due to the sticking material performance of its smooth surface, the smooth surface is prone to form a vacuum with the carrier film, and the adhesion force is extremely large; the texture of the fluorescent film is relatively soft, and forced picking causes damage and rupture of the fluorescent film, increasing the operation risk and reducing the product operability. Moreover, when the fluorescent film is bonded to the LED chip, the bonding force is also relatively low. Under a certain (force, temperature, humidity field change) application environment, the stress generated may cause the fluorescent film to be poorly bonded to the LED chip and break away, resulting in possible abnormalities in the product reliability. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method of a fluorescent film, which can prepare a fluorescent film with good light output uniformity, adhesiveness, and low sticking property.

[0006] Achieving the above purpose includes the following technical solutions.

[0007] The first aspect of the present invention provides a preparation method of a fluorescent film, and the preparation method includes the following steps:

[0008] Divide the fluorescent glue into two groups, and coat the first group of fluorescent glue on a carrier to form a first fluorescent film layer; wherein, the carrier is placed on a heating stage, and the temperature of the heating stage is 70°C to 90°C; wherein, the fluorescent glue is prepared from phosphors, encapsulation glue, and a diluent.

[0009] Raise the temperature of the heating stage and stabilize it to 100°C to 130°C, and coat the second group of fluorescent glue on the first fluorescent film layer to form a second fluorescent film layer.

[0010] Place the carrier coated with the first fluorescent film layer and the second fluorescent film layer in an oven at 100°C to 150°C for baking and curing, take it out and cool it to room temperature, and peel off the fluorescent film from the carrier to obtain the fluorescent film.

[0011] In some of these embodiments, in the step of coating the first group of fluorescent glue onto the carrier to form the first fluorescent film layer, the temperature of the heating stage is 75°C to 85°C, preferably 78°C to 82°C;

[0012] In the step of coating the second group of fluorescent glue onto the first fluorescent film layer to form the second fluorescent film layer, the temperature of the heating stage is 110°C to 120°C, preferably 113°C to 117°C.

[0013] In some of these embodiments, the surface roughness of the surface of the carrier in contact with the first group of fluorescent glue is 1.2 μm to 1.7 μm.

[0014] In some of these embodiments, a spraying device is used to spray the first group of fluorescent glue onto the carrier in multiple times to form the first fluorescent film layer.

[0015] In some of these embodiments, a spraying device is used to spray the second group of fluorescent glue onto the first fluorescent film layer to form the second fluorescent film layer.

[0016] In some of these embodiments, the first group of fluorescent glue is sprayed onto the carrier 2 to 4 times to form the first fluorescent film layer.

[0017] In some of these embodiments, the weight ratio of the phosphor, encapsulant, and diluent is 1:2 to 4:2 to 3; and / or,

[0018] The encapsulant is one or more of silicone rubber and epoxy resin; and / or,

[0019] The diluent is one or more of ethanol, isopropanol, acetone, and toluene; and / or,

[0020] In some of these embodiments, the carrier is a release film, preferably an ETFE release film or a fluorine film, and the surface roughness of the release film is 1.2 μm to 1.7 μm.

[0021] In some of these embodiments, after the coating of the second fluorescent film layer is completed, it is left standing for 1 min to 2 min for micro-curing and forming.

[0022] In some of these embodiments, the thickness of the fluorescent film is 50 μm to 70 μm, preferably 55 μm to 65 μm; preferably, the thickness ratio of the first fluorescent film layer to the second fluorescent film layer is 2 to 3:1.

[0023] The second aspect of the present invention provides a fluorescent film, and the fluorescent film is prepared by the preparation method as described above.

[0024] The third aspect of the present invention provides an LED lamp, and the LED lamp includes a package, an LED chip, and the fluorescent film as described above;

[0025] The encapsulation member has a receiving cavity with a light-emitting opening on one side. The LED chip is disposed in the receiving cavity, and the fluorescent film is disposed at the light-emitting opening of the encapsulation member. One side of the fluorescent film close to the second fluorescent film layer is adhered to the surface of the LED chip through an adhesive layer.

[0026] The technical solution provided by the present invention has the following advantages and effects:

[0027] In the preparation method of the fluorescent film, a solution-like fluorescent glue is prepared by mixing phosphor powder, encapsulation glue and diluent. The fluorescent glue is divided into two groups, and the specific heating stage coating temperature when the two groups of fluorescent glue are coated to form a fluorescent film layer is controlled, so that the flow state and curing state of the fluorescent glue on the heating stage can be well controlled. As a result, the phosphor powder in the prepared fluorescent film is evenly distributed, and the surface has a specific roughness (1 μm - 2 μm). The uniformly formed structure inside the fluorescent film and the specific rough surface on the surface can improve the light-emitting uniformity. Moreover, when the fluorescent film with the specific rough surface adheres to the carrier film during transportation, the viscosity between the fluorescent film and the carrier film can be reduced, and it is not easy to form a vacuum environment with the carrier film, reducing the adhesion force and improving the product workability. At the same time, when assembled to the LED lamp and adhered to the LED chip, the contact area between the adhesive and the fluorescent film can be increased, improving the adhesion strength, making the bonding between the LED chip and the fluorescent film firm. The surface roughness of the finished LED lamp bead is relatively low, reducing the risks of lamp bead packaging and chip bonding. Description of the Drawings

[0028] Figure 1 It is a physical diagram of the fluorescent film corresponding to the first fluorescent film layer in Embodiment 1 of the present invention.

[0029] Figure 2 It is a physical diagram of the fluorescent film corresponding to the second fluorescent film layer in Embodiment 1 of the present invention.

[0030] Figure 3 It is a physical diagram of the fluorescent film corresponding to the second fluorescent film layer in Embodiment 2 of the present invention.

[0031] Figure 4 It is a physical diagram of the fluorescent film corresponding to the second fluorescent film layer in Embodiment 3 of the present invention.

[0032] Figure 5 It is a physical diagram of the glue overflow of the LED lamp in Embodiment 3 of the present invention.

[0033] Figure 6 It is a specific structure diagram of the LED lamp in the embodiment of the present invention.

[0034] Description of the Reference Numerals:

[0035] 1. Encapsulation; 2. LED chip; 3. Fluorescent film; 4. Adhesive layer. Detailed implementation

[0036] To facilitate the understanding of the present invention, the specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings of the specification.

[0037] Unless otherwise specified or defined, the "first, second..." used herein is only for differentiating names and does not represent a specific quantity or order.

[0038] Unless otherwise specified or defined, the term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0039] It should be noted that "fixed to" and "connected to" herein can be directly fixed or connected to an element, or indirectly fixed or connected to an element.

[0040] The embodiment of the present invention provides a method for preparing a fluorescent film, and the preparation method includes the following steps:

[0041] Divide the fluorescent glue into two groups, and coat the first group of fluorescent glue onto a carrier to form a first fluorescent film layer; wherein, the carrier is placed on a heating stage, and the temperature of the heating stage is 70°C to 90°C; wherein, the fluorescent glue is prepared from a phosphor, an encapsulating glue, and a diluent;

[0042] Raise the temperature of the heating stage and stabilize it to 100°C to 130°C, and coat the second group of fluorescent glue onto the first fluorescent film layer to form a second fluorescent film layer;

[0043] Place the carrier coated with the first fluorescent film layer and the second fluorescent film layer in an oven at 100°C to 150°C for baking and curing, take it out and cool it to room temperature, and peel off the fluorescent film from the carrier to obtain the fluorescent film.

[0044] In the present invention, the inventor found in the research on fluorescent films that, in order to ensure good light emission uniformity in the existing fluorescent film process, a viscous fluorescent glue is usually obtained by mixing phosphor powder and encapsulation glue, and the fluorescent glue is directly coated on a film substrate and cured to obtain a fluorescent film. The viscous glue-like fluorescent glue can be quickly cured on the film substrate, thereby preparing a fluorescent film with two smooth surfaces (roughness less than 0.5 μm). However, the fluorescent film with two smooth surfaces has problems such as poor adhesion, being unfavorable for transportation operations, and sticking materials. Among them, since the fluorescent film needs to be carried on a carrier film for transportation during the transportation process to maintain the integrity of the fluorescent film, due to its sticking material performance, the fluorescent film is prone to form a vacuum environment with the carrier film during the transfer process, with extremely large adhesion, reducing the workability of the product. Moreover, when the fluorescent film is bonded to an LED chip, the bonding force is also relatively low. In an application environment with certain unevenness of heat and cold, the fluorescent film may be poorly bonded to the LED chip and become detached, resulting in possible abnormalities in the reliability of the product.

[0045] To solve the above problems, the inventor found that by mixing phosphor powder, encapsulation glue, and a diluent to prepare a liquid fluorescent glue, dividing the fluorescent glue into two groups, and controlling the specific coating temperature of the heating stage when the two groups of fluorescent glue are coated to form a fluorescent film layer, the flow state and curing state of the fluorescent glue on the heating stage can be well controlled. As a result, the phosphor powder in the prepared fluorescent film is evenly distributed, and the surface has a specific roughness (1 μm - 2 μm). The uniformly formed structure inside the fluorescent film and the specific rough surface on the surface can improve the light emission uniformity. Moreover, when the fluorescent film with the specific rough surface adheres to the carrier film during transportation, the viscosity between the fluorescent film and the carrier film can be reduced, and it is not easy to form a vacuum environment with the carrier film, reducing the adhesion force and improving the workability of the product. At the same time, when it is assembled to an LED lamp and bonded to the LED chip, the contact area between the adhesive and the fluorescent film can be increased, improving the bonding strength, making the LED chip and the fluorescent film firmly bonded. The surface roughness of the finished LED lamp bead is relatively low, reducing the risks of lamp bead packaging and patch sticking.

[0046] Preferably, in some embodiments, in the step of coating the first group of fluorescent glue onto the carrier to form the first fluorescent film layer, the temperature of the heating stage is 75°C to 85°C, more preferably 78°C to 82°C. Under the control of this specific coating temperature, the diluent in the fluorescent glue can volatilize while having a good flatness on the side away from the carrier, preventing the uneven and jagged coarsening of the second fluorescent film layer, and effectively avoiding affecting the control of the roughness of the second fluorescent film layer away from the first fluorescent film layer; in the step of coating the second group of fluorescent glue onto the first fluorescent film layer to form the second fluorescent film layer, the temperature of the heating stage is 110°C to 120°C, more preferably 113°C to 117°C, which can make the powder inside the fluorescent film evenly distributed and form a surface with a specific roughness (1 μm - 2 μm).

[0047] In some embodiments, a spraying device is used to spray the first group of fluorescent glue onto the carrier in multiple times to form the first fluorescent film layer.

[0048] In some embodiments, a spraying device is used to spray the second group of fluorescent glue onto the first fluorescent film layer once to form the second fluorescent film layer.

[0049] In some embodiments, the fluorescent glue is composed of a mixture of phosphor powder, encapsulant glue, and diluent, and the weight ratio of the phosphor powder, encapsulant glue, and diluent is 1:2 - 4:2 - 3. Specifically, the encapsulant glue can be one or more of silicone rubber and epoxy resin. The phosphor powder can be single powder or mixed powder with different wavelengths, such as red powder, yellow-green powder, etc. The phosphor powder can also contain other additive substances beneficial to product performance or stability, which are used to convert the blue light of the chip to obtain the required light color. The diluent can be diluting solvents such as ethanol, isopropanol, acetone, and toluene. Among them, the preparation method of the fluorescent glue is: adding the phosphor powder, encapsulant glue, and diluent into a vacuum degassing machine and stirring for 4 min to 10 min to obtain a homogeneous solution of the fluorescent glue.

[0050] In some embodiments, after the coating of the second fluorescent film layer is completed, it is left standing for 1 min to 2 min for micro-curing and forming, and then transferred to an oven for baking and curing.

[0051] In some embodiments, the thickness of the fluorescent film is 50 μm to 60 μm, preferably 55 μm to 65 μm. The thickness ratio of the first fluorescent film layer to the second fluorescent film layer is 2 - 3:1; preferably 2.4 - 2.6:1.

[0052] In some embodiments, the carrier is a release film, specifically a high-temperature resistant ETFE release film, fluorine film, etc., and its roughness is 1.2 μm to 1.7 μm (Ra). Among them, controlling the roughness of the release film to be 1.2 μm to 1.7 μm can control the surface roughness of the first fluorescent film layer far from the second fluorescent film layer to be 1.2 μm to 1.7 μm, so that the roughness of both sides of the fluorescent film is basically the same, and it is not necessary to distinguish the front and back sides during transportation or when bonding LED lights, effectively improving the efficiency and avoiding errors.

[0053] The embodiment of the present invention also provides a fluorescent film, which is prepared by the above-mentioned method for preparing the fluorescent film. Among them, the fluorescent film prepared by the above-mentioned method for preparing the fluorescent film can be cut by a metal knife or laser to obtain a single fluorescent film matching the LED chip, and can be cut according to a single side exceeding the chip by 30-50μm. The size is adjusted according to the actual application. For example, it can be cut into a single fluorescent film with a size of 1.06mm*1.06mm and a chip with a size of 1.0mm*1.0mm. The cut film is placed on the carrier film after testing, appearance inspection and other processes, wherein the rough surface of the fluorescent film and the contact surface of the carrier film cannot form a vacuum fit, the adhesion is reduced, and the two can be quickly peeled off. When attaching the film, the mother-and-child ring can be directly used to appropriately expand the film. The operation can be compatible with conventional crystal bonding machines, saving equipment resources.

[0054] The embodiment of the present invention further provides an LED lamp, such as Figure 3 As shown, the LED lamp includes a package 1, an LED chip 2 and the fluorescent film 3 as described above; the package 1 has a housing cavity with a light outlet on one side, the LED chip 2 is arranged in the housing cavity, the fluorescent film 3 is arranged at the light outlet of the package 1, and the fluorescent film 3 is bonded to the surface of the LED chip 2 through an adhesive layer 4. The package 1 can be a dam structure formed by curing white wall glue or high reflective glue. The fluorescent film 3 and the LED chip 2 can be bonded by adhesive. The LED chip 2 can be a blue light chip, etc.

[0055] The present invention is described below with reference to specific embodiments.

[0056] Example 1

[0057] This embodiment provides a method for preparing a fluorescent film, comprising the following steps:

[0058] The high temperature resistant ETFE release film (Ra = 1.2 ~ 1.7μm) was flatly fixed on the surface of the heating platform, and the temperature of the heating platform was controlled at 80°C. The red powder (peak 620nm): yellow-green powder (551nm): silica gel: toluene = 0.975: 0.025: 2: 1.5 weight ratio was prepared to obtain fluorescent glue, and the fluorescent glue was divided into two groups. The first group of fluorescent glue was sprayed on the release film by a coating device in equal amounts and three times to obtain a uniform first fluorescent film layer.

[0059] Raise the temperature of the stage and stabilize it at 115 °C. Spray the second group of fluorescent glue onto the first fluorescent film layer through a coating device to form a second fluorescent film layer. After spraying, let it stand for 2 minutes. Place the carrier sprayed with the first and second fluorescent film layers in an oven (100 °C / 1H + 150 °C / 4H) for baking and curing. Take it out and cool it to room temperature. Peel the fluorescent film off the release film to obtain the fluorescent film. The thickness of the obtained fluorescent film is about 60 μm, the first fluorescent film layer is about 43 μm thick, and the second fluorescent film layer is about 17 μm thick. The corresponding surface of the fluorescent film to the first fluorescent film layer is as Figure 1 shown, and the corresponding surface to the second fluorescent film layer is as Figure 2 shown ( Figure 1 and Figure 2 have slightly different shooting lights, angles, and supporting substrates, resulting in slightly different color displays in the pictures, but the actual colors are the same).

[0060] Example 2

[0061] This example provides a method for preparing a fluorescent film, which includes the following steps:

[0062] Fix the high-temperature resistant ETFE release film (Ra = 1.2 - 1.7 μm) flatly on the surface of the heating stage, and control the temperature of the heating stage at 50 °C. Prepare fluorescent glue by mixing red powder (peak 620 nm): yellow-green powder (551 nm): silica gel: toluene in a weight ratio of 0.975:0.025:2:1.5. Divide the fluorescent glue into two groups. Spray the first group of fluorescent glue onto the release film evenly in three portions through a coating device to obtain the first fluorescent film layer.

[0063] Raise the temperature of the stage and stabilize it at 70 °C. Spray the second group of fluorescent glue onto the first fluorescent film layer through a coating device to form a second fluorescent film layer. After spraying, let it stand for 2 minutes. Place the carrier sprayed with the first and second fluorescent film layers in an oven (100 °C / 1H + 150 °C / 4H) for baking and curing. Take it out and cool it to room temperature. Peel the fluorescent film off the release film to obtain the fluorescent film. The thickness of the obtained fluorescent film is 57 μm, the first fluorescent film layer is about 42 μm, and the second fluorescent film layer is about 15 μm. The corresponding surface of the fluorescent film to the second fluorescent film layer is as Figure 3 shown.

[0064] Example 3

[0065] This example provides a method for preparing a fluorescent film, which includes the following steps:

[0066] The high temperature resistant ETFE release film (Ra = 1.2 ~ 1.7μm) was flatly fixed and attached to the surface of the heating platform, and the temperature of the heating platform was controlled at 120°C. The red powder (peak 620nm): yellow-green powder (551nm): silica gel: toluene = 0.975: 0.025: 2: 1.5 weight ratio was prepared to obtain fluorescent glue, and the fluorescent glue was divided into two groups. The first group of fluorescent glue was sprayed on the release film by a coating device in an even amount and three times to obtain the first fluorescent film layer.

[0067] The temperature of the carrier is increased and stabilized to 200°C, and the second group of fluorescent glue is sprayed on the first fluorescent film layer through a coating device to form a second fluorescent film layer. After spraying, it is allowed to stand for 2 minutes, and the carrier sprayed with the first fluorescent film layer and the second fluorescent film layer is placed in an oven (100°C / 1H+150°C / 4H) for baking and curing. After being taken out and cooled to room temperature, the fluorescent film is peeled off from the release film to obtain a fluorescent film. The thickness of the obtained fluorescent film is 65μm, the first fluorescent film layer is about 45μm, and the second fluorescent film layer is about 20μm.

[0068] The fluorescent film corresponds to the second fluorescent film layer such as Figure 4 shown.

[0069] The binding force, color temperature difference, surface roughness of the first fluorescent film layer and the surface roughness of the second fluorescent film layer obtained in the above embodiments and comparative examples were tested, and the results are shown in Table 1 below (6000K±50K material was selected for comparison and verification in this experiment, and the amount of other materials except the difference in fluorescent film was unified).

[0070] The roughness is tested using a roughness meter.

[0071] The color temperature difference is tested using a illuminance meter method: the color temperature difference is tested at the center and the four corners of a square with a radius of 1 meter at a distance of 1 meter.

[0072] The binding force of the fluorescent film is tested by pushing the film sideways using a thrust tester.

[0073] Table 1 Related properties of fluorescent film

[0074]

[0075] As shown in Table 1, the fluorescent film prepared in Example 1 has good light uniformity and bonding strength, and the roughness of both sides of the fluorescent film is greater than 1 μm (the roughness greater than 1 μm can reduce the viscosity of the fluorescent film and the carrier film). In Example 2, sagging occurs. Due to the low temperature, the diluent cannot evaporate in time during the spraying process, and the fluorescent glue overflows, resulting in poor fluid molding, resulting in uneven distribution of powder inside the fluorescent glue, forming regional block clusters ( Figure 3), and the second fluorescent film layer has a smooth surface with relatively low bonding strength; orange peel phenomenon appears in Example 3. Since the temperature is relatively high when preparing the first fluorescent film layer, the surface roughness of the first fluorescent film layer facing away from the carrier is relatively large, making the cumulative surface of the second fluorescent film layer more uneven. In actual application, due to the overly rough surface of the second fluorescent film layer of the fluorescent film, when preparing the LED lamp, the white wall glue around will overflow onto the surface of the fluorescent film as Figure 5 , which affects its luminous optoelectronic performance and appearance. In actual application, the roughness of the fluorescent film is preferably maintained at about 1-2 μm.

[0076] The above embodiments are not exhaustive listings based on the present invention. In addition, there may be multiple other embodiments not listed. Any substitution and improvement made on the basis of not violating the concept of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a fluorescent film, characterized in that: The preparation method comprises the following steps: Divide the fluorescent glue into two groups, and apply the first group of fluorescent glue to the carrier to form a first fluorescent film layer; wherein the carrier is placed on a heating platform, and the temperature of the heating platform is 70° C. to 90° C.; wherein the fluorescent glue is prepared by including fluorescent powder, encapsulating glue and diluent; Raising the temperature of the heating stage and stabilizing it to 100° C. to 130° C., and applying a second group of fluorescent glue on the first fluorescent film layer to form a second fluorescent film layer; The carrier coated with the first fluorescent film layer and the second fluorescent film layer is placed in an oven at 100°C to 150°C for baking and curing, taken out and cooled to room temperature, and the fluorescent film is peeled off from the carrier to obtain the fluorescent film.

2. The preparation method according to claim 1, characterized in that In the step of coating the first group of fluorescent glue on the carrier to form the first fluorescent film layer, the temperature of the heating stage is 75° C. to 85° C.; In the step of coating the second group of fluorescent glue on the first fluorescent film layer to form the second fluorescent film layer, the temperature of the heating stage is 110°C to 120°C.

3. The preparation method according to claim 1, characterized in that: The weight ratio of the phosphor, the encapsulating glue and the diluent is 1:2-4:2-3; and / or, The packaging glue is one or more of silica gel and epoxy resin; and / or, The diluent is one or more of ethanol, isopropanol, acetone and toluene.

4. The preparation method according to claim 1, characterized in that: The carrier is a release film, and the surface roughness of the release film is 1.2 μm to 1.7 μm.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The first group of fluorescent glue is sprayed onto the carrier in equal amounts multiple times using a spraying device to form the first fluorescent film layer.

6. The preparation method according to any one of claims 1 to 4, characterized in that: The second group of fluorescent glue is sprayed on the first fluorescent film layer by using a spraying device to form the second fluorescent film layer.

7. The preparation method according to claim 5, characterized in that: The first group of fluorescent glue is sprayed on the carrier 2 to 4 times to form a multi-layer first fluorescent film layer.

8. The preparation method according to any one of claims 1 to 4, characterized in that: After the coating of the second fluorescent film layer is completed, the coating is allowed to stand for 1 to 2 minutes; and / or, The thickness of the fluorescent film is 50 μm to 70 μm; preferably, the thickness ratio of the first fluorescent film layer to the second fluorescent film layer is 2 to 3:

1.

9. A fluorescent film, characterized in that: The fluorescent film is prepared by the preparation method according to any one of claims 1 to 8.

10. An LED lamp, characterized in that: The LED lamp comprises a package, an LED chip and the fluorescent film according to claim 9; The package has a housing cavity with a light outlet on one side, the LED chip is arranged in the housing cavity, the fluorescent film is arranged at the light outlet of the package, and the fluorescent film is bonded to the surface of the LED chip through an adhesive layer.

Images