JP2017112295A - Light-emitting device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce color unevenness of a light-emitting device.SOLUTION: A sealing resin 12 is composed of silicone resin, i.e., a phosphor resin 12A mixed with phosphor, and transparent resins 12B, C not mixed with phosphor and transmitting light. The transparent resin 12B is provided to fill the gap between adjoining light-emitting elements 11. Out of the side faces of the light-emitting element 11, a side face 11b adjacent to other light-emitting element 11 is in contact with the transparent resin 12B. Furthermore, the transparent resin 12B is provided to fill a gap 13 between the light-emitting element 11 and a substrate 10, and to also serve as an underfill. The phosphor resin 12A is provided to cover the light-emitting element 11 and the transparent resin 12B. The transparent resins 12C is provided to cover the phosphor resin 12A.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device in which a plurality of light emitting elements are mounted on a substrate and the light emitting elements are sealed with a sealing resin mixed with a phosphor. Moreover, it is related with the manufacturing method.

  As a white light source such as an illumination or a backlight, a light emitting device in which a plurality of blue light emitting elements are mounted on a substrate and sealed with a sealing resin mixed with a yellow phosphor is widely known. In this light emitting device, part of blue light from the light emitting element is converted by a yellow phosphor, and white light is realized by mixing the yellow light and the blue light of the light emitting element.

  Patent Document 1 shows a structure in which a groove for separating each light emitting element is provided in a sealing resin mixed with a phosphor that seals the light emitting element, and the groove is filled with a transparent resin. The sealing resin mixed with the phosphor remains on the side surfaces between the light emitting elements. This describes that ring-shaped light emission unevenness can be eliminated.

  Patent Document 2 discloses a structure in which a light emitting element is sealed with a sealing resin mixed with a phosphor, and the sealing resin is covered with a transparent resin, and this structure can suppress uneven color. Have been described.

JP 2012-109291 A International Publication No. 2005/104247 Pamphlet

  However, the conventional light emitting device has a problem in that color unevenness occurs in the lattice pattern reflecting the arrangement pattern of the light emitting elements, resulting in poor color quality. According to the light emitting devices of Patent Documents 1 and 2, although the color unevenness can be reduced to some extent, the color unevenness of the lattice pattern has not been reduced.

  Accordingly, an object of the present invention is to reduce color unevenness reflecting an arrangement pattern of light emitting elements in a light emitting device in which a plurality of light emitting elements are mounted on a substrate.

  The present invention provides a light emitting device having a substrate, a plurality of light emitting elements mounted on the substrate, and a sealing resin that seals the light emitting elements on the substrate. 1 transparent resin and a phosphor resin in which a phosphor is mixed, and the first transparent resin is located in a region between the light emitting elements, and on the side of the light emitting element adjacent to the other light emitting elements. A light emitting device characterized in that it is in contact with a side surface and located in a region between a substrate and a light emitting element, and the phosphor resin is located so as to cover the light emitting element and the first transparent resin. is there.

  The phosphor resin is desirably located on the side surface of the light emitting element that is not adjacent to the light emitting element. Further reduction in color unevenness can be achieved.

  The sealing resin may be positioned so as to cover the phosphor resin, and may include a second transparent resin that transmits light. As a result, the phosphor resin can be protected to improve the environmental resistance, and the color unevenness can be further reduced.

  The distance between adjacent light emitting elements is preferably 10 to 100 μm. Within this range, color unevenness can be further reduced, and a plurality of light emitting elements can be arranged efficiently. More preferably, it is 30-70 micrometers, More preferably, it is 45-55 micrometers.

  A dam may be provided on the substrate and on the outer periphery of the substrate so as to surround the plurality of light emitting elements. The sealing resin can be accurately formed in a predetermined region inside the dam, and the light can be efficiently extracted to the upper part by reflecting the light by the dam.

  Another aspect of the present invention is a mounting process in which a plurality of light emitting elements are arranged and mounted on a substrate at a predetermined interval, and another light emitting element among the side surfaces of the light emitting elements in a region between the light emitting elements by screen printing. The first transparent resin that transmits light is applied so as to be in contact with the side surface adjacent to the substrate, and the first transparent resin is flowed and filled in a region between the substrate and the light emitting element. The first resin sealing step for curing the resin and the phosphor resin mixed with the phosphor so as to cover the light emitting element and the first transparent resin are applied by screen printing, and then the phosphor resin is applied. And a second resin sealing step for curing. A method for manufacturing a light-emitting device.

  In the second resin sealing step, the phosphor resin may be applied and cured on the side surface of the light emitting element that is not adjacent to the other light emitting element.

  You may have the 3rd resin sealing process of apply | coating 2nd transparent resin so that fluorescent substance resin may be covered by screen printing after a 2nd resin sealing process, and hardening after that.

  After the mounting step and before the third resin sealing step, the resin is applied by screen printing on the substrate and on the outer periphery of the substrate so as to surround the plurality of light emitting elements, and then cured, You may have the dam formation process which forms the dam which accumulates 2 transparent resin.

  The mounting process may be a process of arranging and mounting the light emitting elements so that the interval between adjacent light emitting elements is 10 to 100 μm.

  According to the present invention, the distance through which light passes through a resin containing a phosphor becomes more uniform, and color unevenness is reduced. In addition, since the transparent resin also serves as an underfill, the manufacturing process can be simplified and the cost can be reduced.

FIG. 3 is a cross-sectional view illustrating a configuration of a light-emitting device of Example 1. FIG. 3 is a plan view illustrating a configuration of a light emitting device according to Example 1; FIG. 6 shows a manufacturing process of the light-emitting device of Example 1. Sectional drawing which showed the structure of the light-emitting device of a modification. Sectional drawing which showed the structure of the light-emitting device of a modification. Sectional drawing which showed the structure of the light-emitting device of a comparative example.

  Hereinafter, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the examples.

  FIG. 1 is a cross-sectional view schematically showing the configuration of the light-emitting device of Example 1, and FIG. 2 is a plan view schematically showing the configuration of the light-emitting device of Example 1. 1 is a cross-sectional view taken along line AA in FIG.

  As illustrated in FIGS. 1 and 2, the light-emitting device of Example 1 includes a substrate 10, a plurality of light-emitting elements 11 mounted on the substrate 10, and a sealing resin 12 that seals the light-emitting elements 11. ing.

The substrate 10 is made of an insulating material having a high thermal conductivity such as AlN or Al ₂ O ₃ . A wiring pattern 10a is formed on the surface of the substrate 10 on the light emitting element 11 mounting side. In addition, on the back surface of the substrate 10 (the surface opposite to the light emitting element 11 mounting side), a heat radiating plate 10b for efficiently releasing heat from the light emitting element 11 to the outside and vias (not shown) are provided. A back electrode 10c connected to the wiring pattern 10a is provided.

  The light emitting element 11 is a blue light emitting flip chip LED made of a group III nitride semiconductor. A plurality of light emitting elements 11 are flip-chip mounted on the substrate 10, and the wiring pattern 10 a formed on the surface of the substrate 10 and the electrodes of the light emitting elements 11 are connected. For example, connection by Ag nano paste. The planar pattern of each light emitting element 11 is a square.

  In addition, as shown in FIG. 2, the light emitting elements 11 are arranged in the form of a 4 × 4 square lattice with a space D therebetween with the sides of the light emitting elements 11 aligned in parallel, and 16 light emitting elements 11 are arranged. The length of one side of the light emitting element 11 is, for example, 300 to 1700 μm.

  The distance D between the light emitting elements 11 is preferably 10 to 100 μm. Within this range, color unevenness can be effectively suppressed, the light-emitting elements 11 can be efficiently arranged within a limited area, and a light-emitting device can be easily manufactured. More preferably, it is 30-70 micrometers, More preferably, it is 45-55 micrometers. For the same reason as described above, the distance D between the light emitting elements 11 is 0.01 to 0.1 times the length of one side of the light emitting element 11 (or the short side when the light emitting element 11 is rectangular). It is good. The ratio is more preferably 0.03 to 0.07 times, and further preferably 0.045 to 0.055 times.

  The sealing resin 12 is made of a silicone resin, and is composed of a phosphor resin 12A in which phosphors are mixed, and transparent transparent resins 12B and C that are not mixed with phosphors and transmit light. The transparent resin 12B corresponds to the first transparent resin of the present invention, and the transparent resin 12C corresponds to the second transparent resin of the present invention. The sealing resin 12 may be mixed with a diffusing agent for diffusing light, for example, particles such as silicon oxide, aluminum oxide, and titanium oxide. When mixing a diffusing agent, it is preferable to mix a diffusing agent only in the transparent resin 12C without mixing the diffusing agent in the phosphor resin 12A and the transparent resin 12B from the viewpoint of suppressing color unevenness. Moreover, the heat conductive filler for thermal radiation may be mixed. Further, a transparent resin other than the silicone resin may be used, for example, an epoxy resin may be used.

  The transparent resin 12B is provided so as to fill a gap between the adjacent light emitting elements 11, and the transparent resin 12B is filled up to the height of the upper surface 11a of the light emitting element 11. Of the side surfaces of the light emitting element 11, the side surface 11b adjacent to the other light emitting element 11 is in contact with the transparent resin 12B. The transparent resin 12B is provided so that the gap 13 between the light emitting element 11 and the substrate 10 is filled, and the transparent resin 12B also serves as an underfill. That is, the transparent resin 12B provided in the gap 13 physically protects the connection portion between the wiring pattern 10a of the substrate 10 and the electrode of the light emitting element 11 from thermal stress and external force, and chemically protects from corrosion and the like. ing. In order to mitigate thermal stress, the transparent resin 12B is preferably made of a material having a small linear expansion coefficient, and the linear expansion coefficient may be adjusted by mixing fillers.

  The transparent resin 12B does not necessarily have to be filled up to the height of the upper surface 11a of the light emitting element 11, but it is desirable that the transparent resin 12B is filled as close to the upper surface 11a as possible in order to suppress color unevenness. For example, the transparent resin 12B is preferably formed to a height of 90% or more of the height from the surface of the substrate 10 to the upper surface 11a, and more preferably 95% or more.

  The phosphor resin 12A is provided so as to cover the light emitting element 11 and the transparent resin 12B. That is, the phosphor resin 12A is in contact with the upper surface 11a (the surface opposite to the substrate 10 side) of the light emitting element 11 and the side surface 11c of the side surfaces of the light emitting element 11 that are not adjacent to the other light emitting elements 11. Covered. Further, the phosphor resin 12A is in contact with the upper surface of the transparent resin 12B filling the space between the light emitting elements 11. As the phosphor mixed in the phosphor resin 12A, any phosphor that emits yellow light when excited by the blue light emitted from the light emitting element 11 can be used. For example, garnet phosphors such as YAG phosphors, LuAG phosphors, and TAG phosphors, BOS phosphors, sialon phosphors, and the like can be used. In addition to the yellow phosphor, a red phosphor or a green phosphor may be mixed to adjust the color temperature or color rendering. The thickness of the phosphor resin 12A is designed according to the desired color temperature and color rendering properties.

  The phosphor resin 12 </ b> A may not be provided on the side surface 11 c that is not adjacent to the other light emitting elements 11 among the side surfaces of the light emitting element 11. However, it is desirable to provide for further reducing color unevenness. Further, the side surface 11c and the phosphor resin 12A are not necessarily in contact with each other, and a transparent resin 12B may be provided between the side surface 11c and the phosphor resin 12A.

  The transparent resin 12C is provided so as to cover the phosphor resin 12A. The transparent resin 12C protects the phosphor resin 12A physically and chemically and prevents the phosphor resin 12A from coming into contact with the outside, such as air, and enhances environmental resistance. Further, the color unevenness is further reduced by diffusing the light transmitted through the phosphor resin 12A by the transparent resin 12C. The transparent resin 12C is not necessarily required, but is desirably provided from the above viewpoint.

  By configuring the sealing resin 12 as described above, it is possible to suppress color unevenness in a lattice pattern that reflects the arrangement pattern of the light emitting elements. This is due to the following reason.

  First, consider the light emitting device of Comparative Example 1 (see FIG. 6) in which the transparent resin 12B is replaced with the phosphor resin 12A in the light emitting device of Example 1.

  In the light emitting device of Comparative Example 1, the phosphor resin 12A exists between the adjacent light emitting elements 11. Therefore, the side surface of the light emitted from the top surface 11a of the light emitting element 11 through the phosphor resin 12A to the outside and the light emitted from the side surface 11b of the light emitting element 11 through the phosphor resin 12A to the outside The light radiated from 11b to the outside has a longer distance for transmitting the phosphor resin 12A. As a result, the ratio that blue light is converted into yellow light increases. Then, the light emitted from the side surface 11b of the light emitting element 11 to the outside is stronger in yellow than the light emitted from the upper surface 11a to the outside. As a result, the planar pattern corresponding to the gap between the light emitting elements 11 In the lattice pattern, yellow became strong and uneven color occurred.

  On the other hand, in the light emitting device of Example 1, there is no phosphor resin 12A between the light emitting elements 11, and a transparent resin 12B is provided. The transparent resin 12B is in contact with the side surface on the other adjacent light emitting element 11 side among the side surfaces of the light emitting element 11, and the phosphor resin 12A is not located at all in the gap between the light emitting elements 11. Therefore, the distance transmitted through the phosphor resin 12A is approximately equal between the light emitted from the upper surface 11a side of the light emitting element 11 and the light emitted from the side surface. That is, the rate at which blue light is converted to yellow light is approximately equal regardless of the direction of light emission from the light emitting element 11. As a result, the difference in the ratio of yellow light depending on the radiation direction from the light emitting elements 11 is eliminated, and the uneven color of the lattice pattern corresponding to the gap between the light emitting elements 11 is suppressed.

  Next, the manufacturing method of the light-emitting device of Example 1 is demonstrated with reference to FIG.

  First, the light emitting elements 11 are mounted on the substrate 10 in a pattern in which the light emitting elements 11 are arranged in a square lattice pattern (see FIG. 3A). The mounting method may be any conventionally known method. For example, an Ag nano paste is applied to a predetermined position of the wiring pattern 10a, and the Ag nano paste and the electrode of the light emitting element 11 are arranged to face each other. The wiring pattern 10a and the electrode of the light emitting element 11 are connected to each other through the Ag nano paste by sintering the Ag nano paste to impart conductivity.

  Next, a transparent resin 12B, which is a silicone resin not mixed with a phosphor, is applied to the adjacent gaps of the light emitting elements 11 by screen printing, and is filled up to the height of the upper surface 11a of the light emitting elements 11. Thus, the transparent resin 12B is filled in the gap so as to be in contact with the side surface 11b adjacent to the other light emitting element 11 among the side surfaces of the light emitting element 11. As a plate for applying the transparent resin 12B to a predetermined region, for example, polymesh is used. At this time, the transparent resin 12B is filled in the gaps 13 between the light emitting elements 11 and the substrate 10 by the flow of the silicone resin (see FIG. 3B). This is possible by adjusting the viscosity of the silicone resin. For example, it can be adjusted according to the material and amount of the filler mixed with the silicone resin. Thus, by making the transparent resin 12B also serve as an underfill, the manufacturing process is simplified and the manufacturing cost is reduced. Thereafter, the transparent resin 12B is cured.

  Next, a phosphor resin, which is a silicone resin mixed with a phosphor so as to cover the upper surface of the transparent resin 12B and the light emitting element 11 and the side surface 11c of the light emitting element 11 where each light emitting element 11 is not adjacent by screen printing. 12A is applied (see FIG. 3C). Then, the phosphor resin 12A is cured. As a plate for applying the phosphor resin 12A to a predetermined region, for example, a SUS mesh is used.

  Next, the transparent resin 12C is applied by screen printing so as to cover the phosphor resin 12A (see FIG. 3D). Thereafter, the transparent resin 12C is cured. As a plate for applying the transparent resin 12C to a predetermined area, for example, polymesh is used. In the formation of the phosphor resin 12A and the transparent resins 12B and C, the mesh material for screen printing is changed according to the molding accuracy, but the same mesh material may be used. Thus, the light emitting device of Example 1 is manufactured.

  Although phosphor resin 12A and transparent resins 12B and C are individually cured, phosphor resin 12A and transparent resins 12B and C may be cured together after application of transparent resin 12C. Further, methods other than screen printing can be used for forming the sealing resin 12, but screen printing is desirable from the viewpoints of ease of molding and simplification of the manufacturing process.

  As described above, according to the light emitting device of the first embodiment, the color unevenness of the grid pattern reflecting the arrangement pattern of the light emitting elements 1 can be suppressed, and the color quality can be improved.

[Modification]
In the light emitting device of Example 1, as shown in FIG. 4, the transparent resin 12B may be provided in a region between the upper surface 11a of the light emitting element 11 and the phosphor resin 12A. Also in this case, similarly to the light emitting device of Example 1, uneven color of the lattice pattern can be suppressed. However, the thickness of the transparent resin 12B located on the upper surface 11a of the light emitting element 11 is desirably 50 μm or less. This is because when the thickness is larger than 50 μm, the color unevenness of the lattice-like pattern cannot be sufficiently suppressed. More desirably, it is 20 μm or less, and further desirably 10 μm or less.

  In the light-emitting device of Example 1, as shown in FIG. 5, the entire region (the entire array of 4 × 4 light-emitting elements 11) in which a plurality of light-emitting elements 11 are provided on the outer periphery of the substrate 10. You may provide the dam 14 so that it may surround. When the sealing resin 12C is applied, the dam 14 prevents the sealing resin 12C from protruding from a predetermined region, and reflects light emitted from the light emitting element 11 in the lateral direction upward to transmit the light. It is provided for effective removal. The dam 14 can be formed by applying a resin by screen printing after the mounting process of the light emitting element 11 and before the forming process of the transparent resin 12C. The dam 14 is preferably a white resin in order to efficiently reflect light. For example, a silicone resin and a diffusing agent such as titanium oxide are mixed. In the case of downsizing the light emitting device, when the substrate 10 is separated for each light emitting device, the light emitting device finally includes the dam 14 as in the first embodiment by separating the substrate 10 in the region inside the dam 14. It may not be possible.

  Alternatively, white ink may be applied to a region on the substrate 10 where the light emitting element 11 is not located. Thereby, light can be efficiently extracted by reflecting light upward. For example, silicone ink is used as the white ink. In this case, light extraction can be performed more efficiently by combining with the formation of the dam 14.

  In Example 1, the plurality of light emitting elements 11 are arranged in a square lattice shape, but it is not necessarily required to have a square lattice shape. However, from the viewpoint of reducing color unevenness and from the viewpoint of efficient arrangement, it is desirable that the arrangement pattern is such that the distance D between the light emitting elements 11 is constant. For example, a triangular lattice arrangement may be used.

  In Example 1, a blue light emitting element made of a group III nitride semiconductor is used as the light emitting element, and a yellow phosphor is used as the phosphor, but the present invention is not limited to this. However, since color unevenness is remarkable in a light emitting device using these light emitting elements and phosphors, the effect of suppressing color unevenness by application of the present invention is high and desirable.

  The light emitting device of the present invention can be used as a light source for illumination, a display device and the like.

10: Substrate 11: Light-emitting element 12: Sealing resin 12A: Phosphor resin 12B: Transparent resin 14: Dam

Claims (10)

In a light emitting device having a substrate, a plurality of light emitting elements mounted on the substrate, and a sealing resin that seals the light emitting elements on the substrate,
The sealing resin includes a first transparent resin that transmits light and a phosphor resin in which a phosphor is mixed;
The first transparent resin is located in a region between the light emitting elements, is in contact with a side surface adjacent to the other light emitting element among the side surfaces of the light emitting element, and the substrate and the light emitting element Located in the area between
The phosphor resin is positioned so as to cover the light emitting element and the first transparent resin.
A light emitting device characterized by that.   2. The light emitting device according to claim 1, wherein the phosphor resin is also located on a side surface of the light emitting element that is not adjacent to the light emitting element.   The light emitting device according to claim 1, wherein the sealing resin includes a second transparent resin that is positioned so as to cover the phosphor resin and transmits light.   4. The light emitting device according to claim 1, wherein an interval between the adjacent light emitting elements is 10 to 100 μm. 5.   5. The dam according to claim 1, wherein a dam is provided on the substrate and on an outer periphery of the substrate so as to surround the plurality of the light emitting elements. 5. Light emitting device. A mounting process in which a plurality of light emitting elements are arranged and mounted on a substrate at a predetermined interval;
By applying a first transparent resin that transmits light so as to be in contact with the side surface adjacent to the other light emitting element among the side surfaces of the light emitting element, in a region between the light emitting elements by screen printing, A first resin sealing step of flowing and filling the first transparent resin in a region between the substrate and the light emitting element, and then curing the first transparent resin;
A second resin sealing step of applying a phosphor resin mixed with a phosphor so as to cover the light emitting element and the first transparent resin by screen printing, and then curing the phosphor resin;
A method for manufacturing a light-emitting device, comprising:   The said 2nd resin sealing process WHEREIN: The said fluorescent substance resin is apply | coated also to the side surface of the side which is not adjacent to the said other light emitting element among the said light emitting elements, and is hardened | cured. Method for manufacturing the light emitting device.   After the second resin sealing step, there is a third resin sealing step in which a second transparent resin is applied by screen printing so as to cover the phosphor resin, and then cured. A method for manufacturing the light emitting device according to claim 6.   After the mounting step and before the third resin sealing step, a resin is applied to the outer periphery of the substrate on the substrate by screen printing so as to surround the plurality of light emitting elements, and then cured. The method of manufacturing a light emitting device according to claim 8, further comprising: a dam forming step of forming a dam for storing the second transparent resin.   10. The mounting method according to claim 6, wherein the mounting step includes mounting the light emitting elements so that an interval between the adjacent light emitting elements is 10 to 100 μm. The manufacturing method of the light-emitting device as described in any one of.

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