JP2013053257A - Wavelength converting structure and method for manufacturing the same, and light-emitting device containing the wavelength converting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength converting structure, a method for manufacturing the same, and a light-emitting device containing the wavelength converting structure.SOLUTION: The wavelength converting structure includes: a fluorescent powder layer containing a first region and a second region, which is positioned above the first region, wherein the first region and the second region have the respective gaps; a first material layer formed in the gap of the first region of the fluorescent powder layer; and a second material layer formed in the gap of the second region of the fluorescent powder layer.

Description

  The present invention relates to a wavelength conversion structure and a manufacturing method thereof, and more particularly, to a wavelength conversion structure having a high light extraction efficiency, a manufacturing method thereof, and a light emitting device including the wavelength conversion structure.

  In recent years, energy issues have become more important and various new types of energy-saving lighting fixtures have been developed. Among them, light emitting diodes (LEDs) have advantages such as high luminous efficiency, low electricity consumption, no mercury, and long service life, and are becoming the next generation lighting fixtures.

As for the white LED for illumination, generally, an LED chip is used in combination with fluorescent powder. For example, by using blue light from a blue LED chip, YAG (Yttrium Aluminum Garnet; Y ₃ Al ₅ O ₁₂ ) yellow fluorescent powder is excited to emit yellow light, and then both are mixed to produce white light. Generate.

  There are two common fluorescent powder application methods: conformal coating and remote phosphor technology. The insulating protective coating is performed by directly applying fluorescent powder to the LED chip to form a fluorescent powder layer. Since fluorescent powder is applied directly to the LED chip, this type of application method has the advantage of a relatively uniform thickness. However, since the LED chip and its carrier may absorb light emitted from the fluorescent powder layer, the overall luminous efficiency may be reduced. In addition, since the fluorescent powder is in direct contact with the LED chip, when the LED chip is in a high temperature state of 100 ° C. to 150 ° C. during operation, the fluorescent powder layer may gradually deteriorate and deteriorate the conversion efficiency. There is.

  Remote phosphor technology is used to solve the above-mentioned problems of the insulating protective coating. Since the fluorescent powder layer and the LED chip of the LED light emitting element by the remote phosphor technology are separated, it is possible to avoid the light emitted from the fluorescent powder layer from being directly absorbed by the LED chip as much as possible. In addition, since the fluorescent powder layer is installed in a manner away from the LED chip, the fluorescent powder in the fluorescent powder layer is unlikely to deteriorate due to high temperatures during operation of the LED chip.

  When the fluorescent powder particles receive light from the LED chip, they can be excited to generate light of other types. However, the light generated by the excitation of the fluorescent powder particles is directed in all directions, and of course includes light propagating inward. Therefore, when the refractive index of the package resin and the fluorescent powder are different, total reflection is likely to occur, and the light emission efficiency is lowered.

  An object of the present invention is to provide a wavelength conversion structure having high light extraction efficiency, a method for manufacturing the same, and a light emitting device having the wavelength conversion structure.

  According to one embodiment of the present invention, a wavelength conversion structure is provided. This wavelength conversion structure is a fluorescent powder layer including a first region and a second region, the second region is located on the first region, and the first region and the second region are fluorescent light having a gap, respectively. A powder layer, a first material layer formed in a gap between the first regions of the fluorescent powder layer, and a second material layer formed in a gap between the second regions of the fluorescent powder layer are included.

  According to one embodiment of the present invention, a wavelength conversion structure is provided. The wavelength conversion structure includes a first material layer, a second material layer, and a plurality of fluorescent powder particles, the second material layer is located on the first material layer, and the plurality of fluorescent powder particles are the first Dispersed in the material layer and the second material layer.

  According to another embodiment of the present invention, a method for manufacturing a wavelength conversion structure is provided. The method for manufacturing a wavelength conversion structure includes a step of providing a substrate and a step of forming a fluorescent powder layer on the substrate, the fluorescent powder layer including a first region and a second region, wherein the second region is A first region and a second region each having a gap; a step of forming a first material layer in the first region; and a second material in the second region. Forming a layer.

  According to another embodiment of the present invention, a light emitting device is provided. The light emitting device includes a carrier, a light emitting element installed on the carrier, a first light guide layer covering the light emitting element and installed on the carrier, and a wavelength conversion located on the first light guide layer. The wavelength conversion structure is a fluorescent powder layer including a conductive substrate, a first region and a second region, wherein the first region is located on the first light guide layer, and the second region is The first region and the second region are located above the first region, and the first region and the second region each have a gap, the first material layer formed in the gap between the first region of the phosphor layer, and the phosphor layer And a second material layer formed in the gap of the second region.

  According to the embodiments of the present invention, it is possible to provide a wavelength conversion structure having high light extraction efficiency, a method for manufacturing the same, and a light emitting device having the wavelength conversion structure.

It is a figure which shows the wavelength conversion structure in one Example of this invention. It is a figure which shows the 1st area | region and 2nd area | region of the fluorescent-powder layer in one Example of this invention. It is a figure which shows a mode that the upper surface of the 2nd material layer with which a 2nd area | region is filled is higher than the top surface of a fluorescent powder layer. It is a figure which shows the photograph by an electron microscope of a mode that a fluorescent powder layer is formed in a board | substrate. It is a figure which shows the photograph by an electron microscope of a mode that a 1st material layer is formed in a 1st area | region. It is a figure which shows the photograph by an electron microscope of a mode that a 2nd material layer is formed in a 2nd area | region. It is a figure which shows the light-emitting device in one Example of this invention.

  Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  In this specification, when it is described that one element or one material layer is placed (formed, arranged, etc.) or connected (coupled, etc.) on another element or another material layer This one element or one material layer is directly installed (formed, arranged, etc.) or connected (coupled) on another element or other material layer, or another element or other material It means that it is indirectly installed (formed, arranged, etc.) or connected (coupled, etc.) on the layer (that is, it has other elements or other material layers between them). In addition, when it is described that one element or one material layer is directly installed (formed, arranged, etc.) or connected (coupled, etc.) on another element or other material layer, It means that there are no other elements or other material layers.

  FIG. 1 is a diagram showing a wavelength conversion structure 10 in one embodiment of the present invention. The wavelength conversion structure 10 includes a conductive substrate 101, a fluorescent powder layer 102, a first material layer 103, and a second material layer 104. The fluorescent powder layer 102 is formed on the conductive substrate 101 and is made of fluorescent powder particles, and there is a gap between the fluorescent powder particles. The fluorescent powder layer 102 includes a first region 105 and a second region 106, the first region 105 is located on the conductive substrate 101, the second region 106 is located on the first region 105, Further, the sum of the thickness of the first region 105 and the thickness of the second region 106 is equal to the thickness of the fluorescent powder layer 102. The first material layer 103 is located on the conductive substrate 101, and the first material layer 103 is a thin layer having an inorganic compound filled in the gaps of the first region 105 and having a thickness smaller than that of the fluorescent powder layer 102. It is obtained by forming. The second material layer 104 is located on the first material layer 103, and the second material layer 104 is formed by filling a gap between the second regions 106 of the fluorescent powder layer 102 with rubber material or glass. .

  The conductive substrate 101 has transparent conductivity, and the material thereof may include a transparent conductive inorganic compound (TCO), but is not limited thereto. The fluorescent powder layer 102 is formed on the conductive substrate 101. The material may include a yellow ceramic fluorescent material (that is, a ceramic fluorescent material that emits yellow light when excited), but is not limited thereto. The range of the particle size of the fluorescent powder particles of the fluorescent powder layer 102 is about 225 to 825 nm, and there is a gap between the fluorescent powder particles. The fluorescent powder layer 102 includes a first region 105 and a second region 106. The thickness of the first region 105 is smaller than the thickness of the fluorescent powder layer 102, and the thickness of the first region 105 and the thickness of the fluorescent powder layer 102 are the same. And the thickness of the second region 106 is equal to the value obtained by subtracting the thickness of the first region 105 from the thickness of the fluorescent powder layer 102.

As shown in FIG. 2, the first material layer 103 described above is formed by filling the gap between the fluorescent powder particles in the first region 105 with an inorganic compound. The material of the inorganic compound is, for example, a metal oxide, such as zinc oxide (ZnO), aluminum oxide (Al ₂ O ₃ ), indium tin oxide (ITO), aluminum zinc oxide (AZO), or indium gallium zinc oxide (InGaZnO). IGZO), but is not limited thereto. When the material of the fluorescent powder layer 102 is a yellow ceramic fluorescent powder, the refractive index thereof is about 2. In this case, the material of the inorganic compound is preferably a material having a refractive index close to that of the fluorescent powder. For example, zinc oxide (ZnO) having a refractive index of about 1.8 to 2 may be used. Since the refractive index of the first material layer 103 and the refractive index of the fluorescent powder layer 102 are close to each other, it is possible to effectively prevent a decrease in luminous efficiency due to a difference in refractive index between materials. In addition, the inorganic compound filled in the gaps between the fluorescent powder particles can also play a role of an adhesive, thereby improving the mechanical strength of the fluorescent powder layer 102.

Moreover, the above-mentioned second material layer 104 is formed by filling a gap between the second regions 106 of the fluorescent powder layer 102 with a rubber material. The material of the second material layer 104 may include silica gel having a refractive index of about 1.45, but is not limited thereto. In other words, the rubber material in this embodiment is silica gel, but in other embodiments, the rubber material is another material such as glass (refractive index of 1.5 to 1.9), resin (refractive index). 1.5 to 1.6), titanium dioxide (TiO ₂ ; refractive index 2.2 to 2.4), silicon dioxide (SiO ₂ ; refractive index 1.5 to 1.7), or magnesium fluoride (MgF; refractive index 1.38) or the like may be used. Further, the second material layer 104 may include an organic compound or an inorganic compound having a refractive index of about 1.3 to 1.6.

  In the present embodiment, the thickness of the second region 106 is equal to the value after the thickness of the first region 105 is subtracted from the thickness of the fluorescent powder layer 102. In another embodiment, as shown in FIG. 3, the thickness of the second material layer 104 is larger than the thickness of the second region 106, that is, the top surface 124 of the second material layer 104 is formed of the fluorescent powder layer 102. It is higher than the top surface 126, and thus the surface of the wavelength conversion structure 10 can be further planarized.

  Hereinafter, the manufacturing method of the wavelength conversion structure 10 in a present Example is demonstrated. First, the conductive substrate 101 is placed in an electrophoresis apparatus, and the conductive substrate 101 may be, for example, ITO glass. As shown in the SEM photograph of FIG. 4, the fluorescent powder layer 102 is formed by depositing the fluorescent powder particles on the surface of the ITO glass by the electrophoresis technique. The fluorescent powder layer 102 in this embodiment includes a material that can convert the wavelength of incident light, for example, a fluorescent material. The deposition method of the fluorescent powder layer 102 is not limited to the electrophoresis technique, and may include other deposition methods such as a gravity deposition method. Next, the first material layer 103 is formed by filling a gap between the first regions 105 of the fluorescent powder layer 102 with a transparent inorganic compound (for example, ZnO) by plating. By filling a transparent oxide having a refractive index close to that of the fluorescent powder, loss due to light scattering can be reduced and the light extraction efficiency of white light can be improved. As shown in the SEM photograph of FIG. 5, the above-described inorganic compound can also serve as a pressure-sensitive adhesive for fluorescent powder particles, thereby improving the mechanical strength of the fluorescent powder layer 102. The deposition thickness of the first material layer 103 may be adjusted according to the size of the fluorescent powder particles and / or the gap. The deposition method of the first material layer 103 is not limited to plating, and may include other methods that can fill the gaps between the fluorescent powder particles with an inorganic compound, such as a CVD method or a Sol-Gel method. Finally, as shown in the SEM photograph of FIG. 6, the rubber material is completely filled in the gap between the second regions 106 of the fluorescent powder layer 102. Since the method of filling the rubber material is well known to those skilled in the art, a detailed description thereof is omitted here. The formed wavelength conversion structure 10 has a substantially uniform or non-uniform thickness.

  FIG. 7 is a diagram showing the light emitting device 20 in one embodiment of the present invention. The light emitting device 20 includes a package substrate 111, a light emitting diode 110, a housing 112, a light guide layer 113, and a wavelength conversion structure 10. The light emitting diode 110 is located on the package substrate 111. The light guide layer 113 covers the package substrate 111 and the light emitting diode 110. The light emitting device 20 includes, for example, the wavelength conversion structure 10 according to the above-described embodiment. The wavelength conversion structure 10 and the light emitting diode 110 are separated by the housing 112, and the fluorescent powder does not come into direct contact with the light emitting diode 110, whereby the light emitted from the fluorescent powder layer is directly absorbed by the light emitting diode 110 (LED chip). You can avoid doing as much as possible. In addition, since the fluorescent powder is installed in a manner away from the light emitting diode 110, the fluorescent powder in the fluorescent powder layer is unlikely to deteriorate due to a high temperature during the operation of the light emitting diode 110.

The light guide layer 113 in this embodiment is a light transmission layer, and may have a material layer that can improve light extraction efficiency. In the present embodiment, the light guide layer 113 includes a plurality of material layers and has a gradient refractive index. In the present embodiment, the plurality of material layers of the light guide layer 113 include a silicon nitride (Si ₃ N ₄ ; refractive index n _a = 1.95) layer and an aluminum oxide (Al ₂ O ₃ ; refractive index n _b = 1). .7) A stack layer composed of a layer and a silicone (silicone; refractive index n _c = 1.45) layer may be used, but in other embodiments, a combination of other material layers may be adopted. . By using a plurality of material layers in which the difference in refractive index between layers is small and the refractive index of each layer gradually decreases along the direction away from the light emitting diode 110, generation of total reflection of light is effectively suppressed. Can do. Examples of usable materials include glass (refractive index: 1.5 to 1.9), resin (refractive index: 1.5 to 1.6), DLC (diamond like carbon; refractive index: 2.0 to 2.4), titanium dioxide (TiO ₂ ; refractive index: 2.2 to 2.4), silicon dioxide (SiO ₂ ; refractive index: 1.5 to 1.7), or magnesium fluoride (MgF; refractive index) May be a combination such as 1.38). In this embodiment, the light emitting diode 110 may be a GaN blue LED chip having a refractive index of 2.4. Therefore, by using a stack layer having a gradient refractive index and a small difference in refractive index between layers, occurrence of total reflection of light can be effectively suppressed.

  In the light emitting device 20 according to the present embodiment, the wavelength conversion structure 10 according to the above-described embodiment is provided on the light guide layer 113, and the wavelength conversion structure passes through the light guide layer 113 after light is emitted from the light emitting diode 110. Enter 10. That is, the light emitted from the light emitting diode 110 passes through the light guide layer 113 having a plurality of material layers, and then enters the second material layer 104 having a relatively low refractive index. It enters into the first material layer 103 having a material close to the refractive index of the powder. Therefore, since the difference in refractive index is relatively small, the loss of light due to total reflection can be effectively reduced. Moreover, since the refractive indexes of the inorganic compound and the fluorescent powder particles are close to each other, light scattering between the fluorescent powder particles can be reduced. Although the light emitting device 20 in this embodiment has a flat package structure, in other embodiments, the shape of the conductive substrate 101 of the wavelength conversion structure 10 is not limited to a flat plate shape, and may be a convex lens shape, a concave lens shape, Alternatively, it may be a triangular pyramid, that is, the surface of the conductive substrate 101 may be a flat surface, a curved surface, or a bent surface.

Table 1 compares the light emission efficiency of the light emitting device 20 having the wavelength conversion structure 10 according to one embodiment of the present invention and the light emission efficiency of the LED light emitting element by the conventional remote phosphor technology. Specifically, according to the present invention, the luminous efficiency of a conventional LED light emitting element in which only the silica gel is filled in the gap between the fluorescent powder layers 102 and the inorganic compound ITO, silica gel, and ZnO are filled in the gap between the fluorescent powder layers 102 by the experiment. The light emission efficiency of the light emitting device 20 having the wavelength conversion structure 10 according to the embodiment will be compared. According to this experiment, the luminous efficiency of the LED light emitting element in which only the silica gel is filled in the gap between the fluorescent powder layers 102 is about 32.15 lumens / watt, and ZnO, silica gel, and ITO material are filled in the gap between the fluorescent powder layers 102. The luminous efficiency of the light emitting device 20 to be filled is about 35.9 to 36.8 lumens / watt. In the latter case, when the ZnO plating time is 45 minutes, the luminous efficiency is about 35.9 lumens / watt, and when the ZnO plating time is 90 minutes, the luminous efficiency is about 36. 8 lumens / watt. As can be seen, the luminous efficiency of the light emitting device 20 having the wavelength conversion structure 10 according to an embodiment of the present invention is about 14% higher than the luminous efficiency of the conventional LED light emitting element. Further, the light emission efficiency of the light emitting element 20 in which the ZnO plating time is 90 minutes is higher than the light emission efficiency of the light emitting element 20 in which the ZnO plating time is 45 minutes. The results are shown in Table 1.
The preferred embodiment of the present invention has been described above, but the present invention is not limited to this embodiment, and all modifications to the present invention are within the scope of the present invention unless departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Wavelength conversion structure 101 Conductive board | substrate 102 Fluorescent powder layer 103 1st material layer 104 2nd material layer 105 1st area | region 106 2nd area | region 110 Light emitting diode 111 Package board | substrate 112 Case 113 Light guide layer 20 Light-emitting device

Claims (20)

A wavelength conversion structure,
A fluorescent powder layer including a first region and a second region, wherein the second region is located on the first region, and the first region and the second region each have a gap. When,
A first material layer formed in a gap between the first regions of the fluorescent powder layer;
A second material layer formed in the gap of the second region of the fluorescent powder layer,
Including a wavelength conversion structure. A wavelength conversion structure,
Including a first material layer, a second material layer, and a plurality of fluorescent powder particles,
The second material layer is located on the first material layer;
The wavelength conversion structure in which the plurality of fluorescent powder particles are dispersed in the first material layer and the second material layer. A conductive substrate located on one side of the first material layer;
The wavelength conversion structure according to claim 1 or 2. The first material layer includes an inorganic compound and / or the second material layer includes an organic compound or an inorganic compound;
The wavelength conversion structure according to claim 1 or 2. The inorganic compound is at least selected from the group consisting of zinc oxide (ZnO), aluminum oxide (Al ₂ O ₃ ), indium tin oxide (ITO), aluminum zinc oxide (AZO), and indium gallium zinc oxide (IGZO). One and / or the second material layer comprises silica gel or glass,
The wavelength conversion structure according to claim 4. The refractive index of the first material layer is substantially 1.8 to 2.0, and / or the refractive index of the second material layer is substantially 1.3 to 1.6.
The wavelength conversion structure according to claim 1 or 2. The fluorescent powder layer includes yellow fluorescent powder,
The wavelength conversion structure according to claim 1. The thickness of the first region is 0.5 to 0.9 times the thickness of the fluorescent powder layer.
The wavelength conversion structure according to claim 1. The upper surface of the second material layer is higher than the top surface of the fluorescent powder layer,
The wavelength conversion structure according to claim 1. The surface of the substrate is a flat surface, a curved surface, or a bent surface, and / or the refractive index of the substrate is substantially 1.7 to 2.0.
The wavelength conversion structure according to claim 3. The difference between the refractive index of the fluorescent powder layer and the refractive index of the first material layer is less than 0.3,
The wavelength conversion structure according to claim 1. The refractive index of the substrate is smaller than the refractive index of the fluorescent powder layer,
The wavelength conversion structure according to claim 3. A method of manufacturing a wavelength conversion structure,
Providing a substrate;
Forming a fluorescent powder layer on the substrate, the fluorescent powder layer including a first region and a second region, wherein the second region is located on the first region; and The one region and the second region each have a gap;
Forming a first material layer in the gap of the first region;
Forming a second material layer in the gap of the second region;
Manufacturing method. The fluorescent powder layer is formed on the substrate by an electrophoresis technique or a gravity deposition method.
The manufacturing method according to claim 13. The first material layer is formed by filling a gap in the first region of the fluorescent powder layer with the first material by a plating method, a CVD method, or a Sol-Gel method, and / or the second material layer. Is formed by rubber filling method,
The manufacturing method according to claim 13. The thickness of the first material layer is 0.5 to 0.9 times the thickness of the fluorescent powder layer.
The manufacturing method according to claim 13. The upper surface of the second material layer is higher than the top surface of the fluorescent powder layer,
The manufacturing method according to claim 13. The refractive index of the substrate is smaller than the refractive index of the fluorescent powder layer,
The manufacturing method according to claim 13. The difference between the refractive index of the fluorescent powder layer and the refractive index of the first material layer is less than 0.3,
The manufacturing method according to claim 13. A light emitting device,
Career,
A light emitting device installed on the carrier;
A first light guide layer covering the light emitting element and disposed on the carrier;
A wavelength conversion structure proximate to the first light guide layer;
Including
The wavelength conversion structure is
A fluorescent powder layer including a first region and a second region, wherein the second region is located on the first region, and the first region and the second region each have a gap. When,
A first material layer formed in a gap between the first regions of the fluorescent powder layer;
A second material layer formed in the gap of the second region of the fluorescent powder layer,
A light emitting device.