JP2016167572A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device capable of suppressing storage of heat while suppressing generation of light emission color unevenness.SOLUTION: A light-emitting device 1 according to an aspect of the present invention includes: a substrate 10; an annular dam 12 formed on the substrate 10; an island-like member 13 formed separated from the dam 12 on an element mounting region 17 surrounded with the dam 12 on the substrate 10; a plurality of light-emitting elements 14 mounted on the element mounting region 17; and a sealing member 16 including phosphor particles 15 filled on the element mounting region 17.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device.

  Generally, in a light emitting device in which a plurality of light emitting elements are mounted on a substrate, such as a COB (Chip on board) type light emitting device, heat generated from phosphor particles dispersed in the light emitting element or the sealing material is generated. Concentrating on the central portion of the element mounting region tends to cause haze, which may cause a reduction in device life and emission characteristics.

  As a conventional light-emitting device, a device in which a plurality of light-emitting elements are mounted on a substrate and no light-emitting element is mounted at the center of the element mounting region is known (for example, Patent Documents 1 to 3).

  According to these light emitting devices, since the light emitting element serving as a heat source is not mounted in the central portion of the element mounting region, the concentration of heat caused by the heat generation of the light emitting element can be reduced.

JP 2013-78336 A JP2013-4739A JP 2012-230967 A

  However, in the light emitting devices of Patent Documents 1 to 3, since the light emitting element is not mounted at the center of the element mounting region, the occupation ratio of the sealing material is higher than the region where the peripheral light emitting element is mounted. Thereby increasing the amount of phosphor particles.

  For this reason, the color of the light emitted from the central part of the element mounting region and the light emitted from the peripheral part are different, and there is a possibility that color unevenness occurs. Further, since the phosphor particles are also a heat source, there is a possibility that the effect of relaxing the concentration of heat may be hindered.

  One of the objects of the present invention is to provide a light-emitting device capable of suppressing thermal clouding while suppressing the occurrence of uneven emission color.

  One embodiment of the present invention provides the following light-emitting devices [1] to [10] in order to achieve the above object.

[1] A substrate, an annular dam formed on the substrate, an island-shaped member formed on the device mounting region surrounded by the dam on the substrate and separated from the dam, and the device mounting A light emitting device comprising: a plurality of light emitting elements mounted on a region; and a sealing material containing phosphor particles filled on the device mounting region.

[2] The light emitting device according to [1], wherein the island-shaped member is formed on a region including a center of the element mounting region.

[3] The light-emitting device according to [2], wherein the island-shaped member has a cross-shaped planar shape.

[4] The light emitting device according to the above [1], wherein the plurality of island-shaped members are arranged so that there is no straight line passing through the element mounting region from the center to the outer periphery without intersecting the island-shaped members.

[5] The light emitting device according to any one of [1] to [4], wherein a position of an upper end of the island-shaped member is higher than a position of an upper end of the light emitting element.

[6] The light emitting device according to any one of [1] to [5], wherein an upper end of the island-shaped member is exposed from a surface of the sealing material.

[7] The light emitting device according to any one of [1] to [5], wherein the island-shaped member is buried in the sealing material.

[8] The light-emitting device according to any one of [1] to [7], wherein the island-shaped member has a portion whose side surface is tapered.

[9] In any one of the above [1] to [7], the island-shaped member has a portion whose side surface is inclined in a reverse taper shape, or a portion where a protrusion that does not contact the substrate is provided on the side surface. The light-emitting device of description.

[10] The light-emitting device according to any one of [1] to [9], wherein the island-shaped member is white or transparent.

  ADVANTAGE OF THE INVENTION According to this invention, the light-emitting device which can suppress a thermal clouding can be provided, suppressing generation | occurrence | production of luminescent color unevenness.

FIG. 1 is a perspective view of the light emitting device according to the first embodiment. 2A and 2B are vertical sectional views of the light emitting device. FIG. 3 is a perspective view of a light emitting device having no island-like member as a comparative example. FIG. 4A is a cross-sectional view of the light-emitting device when the island-shaped member has a portion whose side surface is tapered. FIG. 4B is a cross-sectional view of the light emitting device when the island-shaped member has a portion whose side surface is inclined in a reverse taper shape. FIGS. 5A and 5B are thermographic images showing the temperature distributions of the light-emitting device having the island-shaped member according to the first embodiment and the light-emitting device not having the island-shaped member according to the comparative example, respectively. is there. FIG. 6A is a top view schematically showing the configuration of the light emitting device according to the second embodiment. FIG. 6B is a top view schematically showing the configuration of the light emitting device according to the first embodiment. FIGS. 7A, 7B, and 7C are top views schematically showing the configuration of the light emitting device according to the third embodiment.

[First Embodiment]
(Configuration of light emitting device)
FIG. 1 is a perspective view of a light emitting device 1 according to the first embodiment. 2A and 2B are vertical sectional views of the light emitting device 1.

  The light emitting device 1 includes a substrate 10 having wirings 11, an annular dam 12 formed on the substrate 10, and a region including the center of the element mounting region 17 that is a region surrounded by the dam 12 on the substrate 10. On the element mounting area 17, the island-shaped member 13 formed away from the dam 12, the plurality of light-emitting elements 14 mounted on the area between the dam 12 and the island-shaped member 13 in the element mounting area 17, And a sealing material 16 including phosphor particles 15 filled therein.

  FIG. 2A is a cross-sectional view when the height of the upper end of the island-shaped member 13 is higher than the height of the surface of the sealing material 16 and the upper end of the island-shaped member 13 is exposed from the surface of the sealing material 16. It is. On the other hand, FIG. 2B is a cross-sectional view when the height of the upper end of the island-shaped member 13 is lower than the height of the surface of the sealing material 16 and the island-shaped member 13 is buried in the sealing material 16. . In FIG. 1, illustration of the sealing material 16 and the phosphor particles 15 included in the sealing material 16 is omitted.

  FIG. 3 is a perspective view of the light emitting device 2 that does not have the island-like member 13 as a comparative example. In the light emitting device 2, the light emitting element 14 is also disposed on a region including the center of the element mounting region 17.

The substrate 10 is, for example, a ceramic substrate such as an Al ₂ O ₃ substrate or an AlN substrate, a metal substrate such as an Al substrate or a Cu substrate whose surface is covered with an insulating film, or a glass epoxy substrate. Although the substrate 10 shown in FIG. 1 is a wiring substrate, it may be a substrate of another form such as a lead frame insert substrate.

  The dam 12 is made of a resin such as a silicone resin or an epoxy resin containing a white dye such as titanium oxide. The planar shape of the dam 12 may be an annular shape, and may be a shape other than a circle such as a polygon. Further, the vertical sectional shape of the dam 12 is not particularly limited.

  The light emitting element 14 is, for example, an LED chip having a chip substrate and a crystal layer including a light emitting layer and a clad layer sandwiching the light emitting layer. Moreover, light emitting elements other than LED chips, such as a laser diode, may be used.

  The light emitting element 14 is connected to the wiring 11 included in the substrate 10 by a bonding wire (not shown), and power is supplied from the outside through the terminal portion 11 a of the wiring 11.

  The fluorescent color of the phosphor particles 15 is not particularly limited. For example, examples of yellow phosphor particles include BOS (barium / orthosilicate) phosphors and YAG (yttrium / aluminum / garnet) phosphor particles. Used. For example, when the emission color of the light emitting element 14 is blue and the fluorescent color of the phosphor particles 15 is yellow, the emission color of the light emitting device 1 is white.

  The sealing material 16 is made of a transparent resin such as a silicone resin or an epoxy resin, for example. The sealing material 16 is formed by dropping molding or the like.

  Unlike the light emitting device 2, the island-shaped member 13 is disposed in a region including the center of the element mounting region 17 of the light emitting device 1 (hereinafter referred to as a central region), and thus the light emitting element 14 is not disposed. For this reason, it is possible to prevent concentration of heat to the central region due to heat generated by the light emitting element 14, and to suppress heat buildup.

  Further, since the island-shaped member 13 is disposed, the sealing material 16 including the phosphor particles 15 is hardly present in the central region. For this reason, the emission chromaticity unevenness of the light emitting device 1 due to the increase in the concentration of the phosphor particles 15 in the central region is suppressed, and the concentration of heat to the central region due to the heat generated by the phosphor particles 15 is prevented, and thus more effective. Therefore, it is possible to suppress hot flashes.

  Furthermore, since the island-shaped member 13 is disposed in the central region, the expansion of the sealing material 16 before and after the operation of the light-emitting device (before and after energization) is compared with the light-emitting device 2 in which the island-shaped member 13 is not disposed. The amount of horizontal displacement due to shrinkage can be reduced, and the occurrence of cracks in the sealing material 16 can be suppressed.

  As shown in FIG. 2A, when the upper end of the island-shaped member 13 is exposed from the surface of the sealing material 16, the amount of the phosphor particles 15 in the central region is further reduced, and thus light emission The chromaticity unevenness can be more effectively suppressed.

  Further, in this case, since the amount of displacement in the horizontal direction due to the expansion and contraction of the sealing material 16 before and after the operation of the light emitting device 1 (before and after energization) can be greatly reduced, the occurrence of cracks in the sealing material 16 is further increased. It can be effectively suppressed. For this reason, the structure in which the upper end of the island-shaped member 13 is exposed from the surface of the sealing material 16 is, for example, a lighting for a stadium where the light-emitting device 1 has a large area of the sealing material 16 and easily generates cracks. It is particularly effective when the light emitting device has a large area used in the above.

  On the other hand, when a member such as a lens is directly mounted on the dam 12, it is required to keep the island-like member 13 low. In such a case, if the structure is such that the island-like member 13 is buried in the sealing material 16 as shown in FIG.

  In order for the island-shaped member 13 to exhibit these functions, the material and shape of the island-shaped member 13 are not particularly limited, but additional functions and effects can be added depending on the material and shape.

  For example, in order for the island-shaped member 13 to exhibit the above function, it is preferable that the island-shaped member 13 has a certain height. For example, the position of the upper end of the island-shaped member 13 is higher than the position of the upper end of the light emitting element 14. High is preferred.

  The island member 13 is preferably made of a material that does not generate heat by absorbing light emitted from the light emitting element 14, that is, a material having a band gap larger than the light emission energy of the light emitting element 14.

  Moreover, by configuring the surface of the island-shaped member 13 with a white material, the light reflectance of the island-shaped member 13 can be improved and the light extraction efficiency can be improved. On the other hand, for example, when the shape of the island-shaped member 13 is a shape that cannot be expected to improve the light extraction efficiency due to light reflection, the island-shaped member 13 is formed of a transparent material to transmit light. Can be made.

  FIG. 4A is a cross-sectional view of the light emitting device 1 when the island-like member 13 has a portion whose side surface is tapered. The cross section of the island-shaped member 13 shown in FIG. 4A is a cross section of a portion whose side surface is inclined in a tapered shape.

  In this case, since light can be reflected in a preferable direction by the island-shaped member 13, the light extraction efficiency can be improved. When the island-shaped member 13 has such a shape, it is preferable that the surface of the island-shaped member 13 is made of a white material in order to improve the light reflectance.

  FIG. 4B is a cross-sectional view of the light emitting device 1 when the island-like member 13 has a portion whose side surface is inclined in a reverse taper shape. The cross section of the island-shaped member 13 shown in FIG. 4B is a cross section of a portion whose side surface is inclined in a reverse taper shape.

  In this case, the island-shaped member 13 can suppress the peeling of the sealing material 16 from the substrate 10. Similarly, when the island-shaped member 13 has a portion provided with a protrusion on the side surface that does not contact the substrate (for example, a case where the upper layer has a two-stage structure in which the width of the upper layer is larger than the width of the lower layer), The island-shaped member 13 can suppress the peeling of the sealing material 16 from the substrate 10. When the island-like member 13 has these shapes, it is preferable that the whole or upper part of the island-like member 13 is made of a transparent material.

  5A and 5B are thermographic images showing the temperature distribution of the light emitting device 1 having the island-shaped member 13 and the light emitting device 2 not having the island-shaped member 13, respectively. On the right side of FIGS. 5A and 5B, a temperature scale indicating the correspondence between the image density and the temperature (° C.) is displayed. In addition, the island-like member 13 included in the light-emitting device 1 whose temperature distribution has been measured is slightly buried in the sealing material 16 as shown in FIG.

  Comparing FIG. 5A and FIG. 5B, it can be seen that the thermal fogging in the central region of the light emitting device 1 is suppressed by the island-shaped member 13.

[Second Embodiment]
2nd Embodiment differs from 1st Embodiment in the planar shape of an island-shaped member. Note that description of other points similar to those of the first embodiment is omitted or simplified.

(Configuration of light emitting device)
FIG. 6A is a top view schematically showing the configuration of the light emitting device 20 according to the second embodiment. In FIG. 6A, illustration of the light emitting element 14, the sealing material 16, and the phosphor particles 15 included in the sealing material 16 is omitted.

  The light emitting device 20 includes an island-like member 21 formed away from the dam 12 on the substrate 10 having the wiring 11, the annular dam 12 formed on the substrate 10, and the region including the center of the element mounting region 17. A plurality of light-emitting elements 14 mounted on a region between the dam 12 and the island-shaped member 21 in the element mounting region 17 and a sealing material including the phosphor particles 15 filled on the element mounting region 17 16.

  As shown in FIG. 6A, the island-shaped member 21 of the present embodiment has a cross-shaped planar shape. Note that the features and properties other than the planar shape are the same as those of the island-like member 13 of the first embodiment.

  FIG. 6B is a top view schematically illustrating the configuration of the light emitting device 1 according to the first embodiment. In FIG. 6B, the light emitting element 14, the sealing material 16, and the phosphor particles 15 included in the sealing material 16 are not shown.

As shown in FIG. 6B, the length (L ₁ , L _2, etc.) of the sealing material between the island-shaped member 13 and the dam 12 is shorter than the diameter of the element mounting region 17. The horizontal displacement due to the expansion and contraction of the sealing material 16 along the direction connecting the island member 13 and the dam 12 is small.

However, the length L ₃ of the sealing material 16 along the longitudinal direction of the island-shaped member 13 in the vicinity of the island-shaped member 13 is close to the diameter of the element mounting region 17. For this reason, the amount of displacement along the longitudinal direction of the island-shaped member 13 in the portion of the length L3 is relatively large, and the occurrence of cracks may not be sufficiently suppressed.

  On the other hand, according to the light emitting device 20 according to the second embodiment, since the island-shaped member 21 has a cross-shaped planar shape, the maximum length of the linearly continuous region of the sealing material 16 is increased. Can be shortened. For this reason, the maximum amount of horizontal displacement due to expansion and contraction of the sealing material 16 can be reduced, and the generation of cracks can be more effectively suppressed.

[Third Embodiment]
The third embodiment differs from the first embodiment in that a plurality of island-shaped members are included, the arrangement of island-shaped members, and the like. Note that description of other points similar to those of the first embodiment is omitted or simplified.

(Configuration of light emitting device)
7A, 7B, and 7C are top views schematically showing the configuration of the light emitting devices 30a, 30b, and 30c according to the third embodiment. 7A, 7 </ b> B, and 7 </ b> C, the light emitting element 14, the sealing material 16, and the phosphor particles 15 included in the sealing material 16 are not illustrated.

  The light emitting devices 30a, 30b, and 30c are formed on the substrate 10 having the wiring 11, the annular dam 12 formed on the substrate 10, and the region including the center of the element mounting region 17, apart from the dam 12. Island-shaped members 31 a, 31 b, or 31 c, a plurality of light emitting elements 14 mounted on the element mounting region 17, and a sealing material 16 including the phosphor particles 15 filled on the element mounting region 17. .

  In the light emitting devices 30a, 30b, and 30c, there is no straight line through which the island-shaped members 31a, 31b, or 31c pass from the center to the outer periphery of the element mounting region 17 without intersecting the island-shaped members 31a, 31b, or 31c. Has been placed. Here, the straight line passing from the center of the element mounting area 17 to the outer periphery is a straight line as shown by a dotted line in FIG. 7A, and no matter which direction the straight line extends from the center of the element mounting area 17, It intersects with the member 31a, 31b, or 31c.

  The fact that there is no straight line passing through the island-shaped members 31a, 31b, or 31c from the center to the outer periphery of the element mounting region 17 means that a portion continuous from the center to the outer periphery of the element mounting region 17 is in the sealing material 16. As a result, the maximum length of the linearly continuous region in the planar direction of the sealing material 16 is shortened. For this reason, the maximum amount of horizontal displacement due to expansion and contraction of the sealing material 16 can be reduced, and the generation of cracks can be more effectively suppressed.

  Further, since the light emitting element 14 can be mounted at the center of the element mounting area 17 of the light emitting devices 30a, 30b, and 30c, the concentration of the phosphor particles at the center of the element mounting area 17 is not particularly increased, and the emission color The occurrence of unevenness is suppressed.

  The island-shaped members 31a, 31b, and 31c of the light emitting devices 30a, 30b, and 30c are examples of island-shaped members according to the present embodiment, and the number, shape, arrangement, and the like of the island-shaped members are not limited. Further, the features and properties other than the planar shape, number, and arrangement are the same as those of the island-like member 13 of the first embodiment.

  Since the island-shaped member according to the third embodiment is not disposed on the central region of the element mounting region 17 where heat is most likely to concentrate, the island-shaped member 13 according to the first embodiment or the second embodiment Compared with the island-shaped member 21 according to the embodiment, the effect of suppressing heat buildup of the light emitting device is low, but the effect of suppressing cracks in the sealing material 16 is high.

  Table 1 below shows a comparison result of the effects of the island-shaped members according to the first to third embodiments.

  The mark “Δ” in Table 1 indicates that it is slightly superior, the mark “◯” indicates that it is excellent, and the mark “◎” indicates that it is extremely excellent. The “number of arranged elements” represents the number of light emitting elements 14 that can be arranged. The larger the exclusive area of the island-like member, the smaller the number of light emitting elements 14 that can be arranged.

(Effect of embodiment)
According to the above-described embodiment, by providing the island-shaped member on the element mounting region 17, it is possible to suppress the thermal clouding while suppressing the occurrence of uneven emission color of the light emitting device. In particular, in the first and second embodiments in which the island-shaped member is disposed on the region including the center of the element mounting region 17, it is possible to more effectively suppress thermal fogging.

  Moreover, according to said embodiment, by providing an island-like member, the length of the area | region linearly continued in the plane direction of the sealing material was shortened, and the horizontal direction by expansion | swelling and shrinkage | contraction of a sealing material The amount of displacement can be reduced, and the occurrence of cracks can be suppressed. In particular, in the third embodiment in which the maximum length of the linearly continuous region in the planar direction of the sealing material is the shortest, the occurrence of cracks in the sealing material can be more effectively suppressed.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.

  Moreover, said embodiment does not limit the invention which concerns on a claim. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

1, 20, 30a, 30b, 30c Light-emitting device 10 Substrate 12 Dam 13, 21, 31a, 31b, 31c Island-like member 14 Light-emitting element 15 Phosphor particle 16 Sealing material

Claims (10)

A substrate,
An annular dam formed on the substrate;
On the element mounting region surrounded by the dam on the substrate, an island-like member formed away from the dam,
A plurality of light emitting elements mounted on the element mounting region;
A sealing material filled in the element mounting region and containing phosphor particles;
A light emitting device. The island-shaped member is formed on a region including the center of the element mounting region.
The light emitting device according to claim 1. The island-shaped member has a cross-shaped planar shape;
The light emitting device according to claim 2. The plurality of island-shaped members are arranged so that there is no straight line passing through the island-shaped member from the center to the outer periphery without crossing the island-shaped member.
The light emitting device according to claim 1. The position of the upper end of the island-shaped member is higher than the position of the upper end of the light emitting element,
The light-emitting device of any one of Claims 1-4. The upper end of the island-shaped member is exposed from the surface of the sealing material,
The light emitting device according to claim 1. The island-shaped member is buried in the sealing material;
The light emitting device according to claim 1. The island-shaped member has a portion whose side surface is tapered.
The light emitting device according to claim 1. The island-shaped member has a portion whose side surface is inclined in a reverse taper shape, or a portion provided with a protrusion that does not contact the substrate on the side surface
The light emitting device according to claim 1. The island-shaped member is white or transparent,
The light emitting device according to claim 1.