JP7299537B2 - light emitting device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a light-emitting device, and more particularly to a light-emitting device provided with a light-transmitting member and a covering member for increasing the efficiency of extracting light from a light-emitting element.

2. Description of the Related Art In recent years, light-emitting devices equipped with semiconductor light-emitting elements such as light-emitting diodes (LEDs) and laser diodes (LDs) as light sources are used in various types of illumination and display devices. In particular, these semiconductor light-emitting devices have low power consumption and long life, so they are attracting attention as light sources for next-generation lighting that can replace fluorescent lamps, and further improvements in luminous output and luminous efficiency are required.

For example, in the light-emitting device proposed in Patent Document 1, a light-emitting element chip, which is an LED, is flip-chip mounted on the bottom of a housing recess provided in a package, which is a mounting substrate. An incident surface of a light extraction increasing member having the shape of a plano-convex lens is optically coupled to the emitting surface of the light emitting element chip. The light extraction increasing member has a refractive index intermediate between that of the sapphire substrate of the light emitting device chip and that of air. The exit surface of the light extraction increasing member is a spherical surface, and light is emitted within a cone at all positions on the exit surface with the center line being the normal to the position and the critical angle being the angle between the center line and the generatrix. It is formed so as to include the emission surface of the element chip. According to this configuration, substantially total reflection does not occur on the exit surface of the light extraction increasing member, so that light can be extracted from the light extraction increasing member without attenuation or disappearance due to multiple reflection. It is said that the utilization efficiency of light can be made relatively high.

Japanese Patent Application Laid-Open No. 2006-351809 JP 2007-019096 A JP 2006-037097 A Japanese Patent Application Laid-Open No. 2006-352061 JP-A-2002-305328 JP-A-10-151794

However, in the light-emitting device described in Patent Document 1, the light emitted from the light-emitting element chip to its side passes through the sealing resin and propagates through the inside of the sealing resin and the package. Absorbed and attenuated. In addition, since the sealing resin is also optically coupled to the incident surface of the light extraction increasing member, the light emitting area on the incident surface is substantially enlarged, and the light component reflected on the output surface of the light extraction increasing member increases. For these reasons, the light emitted from the light-emitting element chip cannot be sufficiently extracted to the outside, and it is difficult to further reduce the size of the device while maintaining the light extraction efficiency.

Further, conventionally, LED light is assumed as a light source, and the structure is designed to enhance the extraction efficiency, and the structure is such that the extracted LED light is wavelength-converted by a separately provided phosphor or the like. Therefore, the light extraction efficiency of the wavelength-converted light emitted from the light-emitting device and the LED light added thereto is reduced due to light scattering, absorption, etc. between the separated LED light source section and the wavelength conversion section. or the directivity of the emitted light is reduced, or the structure causes color unevenness or brightness unevenness, or the emission characteristics of the emitted light from the device are insufficient. may be Furthermore, in such a structure in which the light source and conversion section are separated, it is difficult to reduce the size of the entire device.

The present invention has been made in view of the above problems, and its purpose is to improve the extraction efficiency of light emitted from a light emitting element, to be able to be miniaturized, to increase the luminous efficiency, and to prevent color unevenness and brightness unevenness. It is an object of the present invention to provide a light-emitting device capable of achieving light-emitting characteristics in which the is suppressed.

A light-emitting device according to the present invention can achieve the above object with the following structures (1) to (13).
(1) A light-transmitting member having a covering member containing a light-reflecting material, a light-emitting surface, and a light-incident surface facing the surface of the covering member and disposed within the surface; A light-emitting element and a light-emitting element on the light-incident side of the light-transmitting member are coupled to the light-incident area surrounded by the outer reflecting area and partly embedded in the covering member. and a wavelength converting member coupled to and excited by the light emitting element.
(2) The light-transmitting member has a convex surface on the light-emitting side, a substantially flat surface at least on the reflection area on the light-incidence side, and a cross-sectional width of the incidence area that is half or less of the light-incidence-side surface. The light-emitting device according to (1) above.
(3) A light-transmitting member having a covering member containing a light-reflecting material, a convex light-emitting surface, and a light-incident surface facing the surface of the covering member and disposed within the covering member. and a light source part that is coupled to an inner incident area surrounded by a reflecting area on a substantially flat surface on the light incident side surface of the light transmitting member and partly embedded in the covering member, the and a light emitting element provided in a light source section, wherein the cross-sectional width of the incident region is half or less of the light incident side surface.
(4) The light-emitting device according to (3) above, further comprising a wavelength conversion member coupled to the light source unit on the incident region side of the light-emitting element and excited by the light-emitting element.
(5) The wavelength conversion member is a plate-like body having first and second main surfaces facing each other, and a plurality of the light emitting elements are bonded to the second main surface, and the incident region The light-emitting device according to any one of (1), (2), and (4) above, wherein the first main surface is bonded to the .
(6) The light-emitting device according to any one of (1) to (5) above, wherein the reflective area is provided on the surface of the light-transmitting member separated from the surface of the covering member.
(7) The light-emitting device has a light-transmitting adhesive for bonding the light-incident surface of the light-transmitting member and the surface of the covering member, and the incident area and the reflecting area are formed by the light-transmitting adhesive. The light-emitting device according to any one of (1) to (6) above, which is provided at the interface with the agent.
(8) Any one of (1) to (5) above, wherein the light transmitting member is provided on the light source unit and on the surface of the covering member, and the reflecting area is an interface between the light transmitting member and the covering member. 1. The light-emitting device according to claim 1.
(9) The light-emitting device according to (8) above, wherein the incidence region protrudes toward the light-emitting side from the reflection region.
(10) The light-emitting device according to any one of (1) to (9) above, wherein the surface shape of the light-emitting side of the light-transmitting member is spherical.
(11) The light-emitting device has a mounting substrate on which the light-emitting element is mounted, and the light-emitting element is electrically connected to the mounting substrate on the mounting surface side facing the surface on the incident area side. The light-emitting device according to any one of (1) to (10) above.
(12) The light source section of the light emitting device includes a wavelength conversion member bonded to the incident region side surface of the light emitting element and excited by the light emitting element, and the covering member extends from the incident region to the light source section. The light-emitting device according to (11) above, which covers the side surface of the mounting substrate and extends onto the surface of the mounting substrate.
(13) The light-emitting device according to (12) above, wherein the covering member is provided in contact with side surfaces of the light-emitting element and the wavelength conversion member, respectively.

The present invention covers the light emitting element of the light source section and the wavelength conversion section coupled thereto with a light reflecting coating member, and extracts the light emitted from the light source of the light emitting element or the combined light source in one direction, That is, the light source is used as one light emitting surface, the light emitting window of the light emitting device is used as a specific region on one surface, and the light transmitting member that encloses the window is joined and covered with the covering member. Light extraction efficiency can be significantly improved, and light emission characteristics with suppressed color and luminance unevenness can be obtained. In particular, a part of the light transmitting member is coupled to the window, and the light component reflected by the inner surface of the light transmitting member in another region is reflected by the covering member, so that the light can be efficiently extracted. That is, even if a light transmitting member having a large amount of light components propagating through the member is used, the extraction efficiency can be increased. A decrease in characteristics can be suppressed. Moreover, since the composite light source is used, the light source portion can be made smaller, which also contributes to the miniaturization of the device.

1A and 1B are a schematic cross-sectional view and a schematic top view of a light emitting device according to an embodiment of the present invention; FIG. FIG. 2 is a schematic cross-sectional view explaining the periphery of a light source portion of the light emitting device of FIG. 1 according to one embodiment of the present invention; 1A to 1D are schematic cross-sectional views (A) to (D) showing light emitting devices of respective calculation models according to the present invention; It is a graph which shows the ratio of the diameter of a light transmission member, the diameter of an incident region, and the light extraction efficiency in each calculation model of this invention. 1 is a schematic cross-sectional view of a light emitting device according to an embodiment of the invention; FIG. 1A to 1D are schematic cross-sectional views showing a method for manufacturing a light-emitting device according to an embodiment of the present invention; 1A is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention, and FIG. It is a schematic sectional drawing explaining the light source part periphery of the light-emitting device which concerns on one embodiment of this invention. 1A to 1C are schematic cross-sectional views of respective light emitting devices according to one embodiment of the present invention; FIG. 1 is a schematic cross-sectional view of a light emitting device according to an embodiment of the invention; FIG. 4 is a graph showing the relationship between a light transmitting member and luminous efficiency in the light emitting device according to the present invention.

Hereinafter, embodiments of the invention will be described with reference to the drawings as appropriate. However, the light-emitting elements and devices described below are for embodying the technical idea of the present invention, and the present invention is not limited to the following. In particular, unless there is a specific description, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are not meant to limit the scope of the present invention only to them, but are merely illustrative examples. Only. Note that the sizes and positional relationships of members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, each of the elements constituting the present invention may be configured with the same member so that a single member may serve as a plurality of elements, or conversely, the function of one member may be performed by a plurality of members. It can also be realized by sharing. In addition, similarly to each embodiment described below, unless otherwise specified, each configuration can be appropriately combined and applied.

(Embodiment 1)
1 and 2 are schematic diagrams of a light-emitting device 100 according to Embodiment 1 of the present invention, and FIG. 1(a) is a schematic cross-sectional view taken along line AA of FIG. 1(b), which is a schematic top view; FIG. 2 is a schematic cross-sectional view of the periphery of the light source section. A light-emitting device 100 of the example shown in FIGS. 1 and 2 mainly includes a light-emitting element 10, a light-transmitting member 20, a covering member 30, a wavelength converting member 40, and a mounting substrate 50. FIG. The substrate 50 includes a frame 55 and wiring 51 on which a plurality of (two in the figure) light emitting elements 10 are flip-chip mounted. The wavelength conversion member 40 has a plate shape and has first and second surfaces facing each other, and the second surface is bonded to the back surface of each light emitting element 10 . The inside of the frame 55 is filled with the covering member 30 containing the light reflecting material 35, and the light emitting element 10 of the light source section and the wavelength converting member 40 are covered with the covering member 30 with the first surface as an exposed surface. ing. The covering member 30 continuously covers the side surface, part of the second surface, and the side surface of the light emitting element 10 . As a result, the light emitted from the light emitting element 10 and/or the wavelength conversion member 40 is reflected and guided toward the light emitting side by the light-reflective covering member 30, and extracted from the first surface of the wavelength conversion member 40. , the first surface serves as a surface-emitting type light source in which the main light extraction window portion, that is, the light-emitting surface is used. The shape and size of the first surface allow it to serve as a light source, and above this light source, a light transmission member 20 as an optical element for the light source is joined to a light incidence area 80 in a partial area on the light incidence side. .

FIG. 2 is a schematic cross-sectional view for explaining the periphery of the light source section of the light emitting device according to Embodiment 1. FIG. As shown in FIG. 2, the light transmitting member 20 includes the first surface of the wavelength converting member 40 on the surface on the light incident side thereof, and is provided on a part of the covering member 30 surrounding the outside thereof. It has a light-emitting surface 21 that serves as a light-emitting surface of the light-emitting device, facing the light-incident surface. The surface on the light incident side faces the first surface of the wavelength conversion member 40, and includes an incident region 80 where light from the light emitting element 10 and/or the wavelength conversion member 40 is incident, and the surface of the coating member 30 outside the incident region 80. and a reflective region 90 facing the . This incident region 80 increases the efficiency of extracting light from the first surface of the wavelength conversion member 40, and as shown in FIGS. . Here, as shown in the figure, the light transmitting member 20 is a hemispherical lens, the center of which is substantially the center of the incident area on the surface of the light source as shown in FIG. optical element. At this time, in the cross section perpendicular to the first surface of the wavelength conversion member 40, the diameter (cross-sectional width) L of the light source section and the incident region 80 is half or less of the radius of curvature r (=R/2) of the light transmission member 20. , L≦(R/2)/2. Part of the light incident from the incident region 80 is emitted to the outside from the light-emitting surface 21, and the remaining light component is reflected to the light incident side on the inner surface of the light-emitting surface 21 to become return light. Most of this return light reaches the reflective area 90 either directly or while repeating multiple reflections on the inner surface of the light transmitting member 20 . The return light incident on the reflection area 90 is reflected by the surface of the light-reflective covering member 30, thereby changing the angle of incidence on the light-emitting side surface 21 of the light-transmitting member 20 and promoting transmission to the outside. be done. Here, as will be described later, it is preferable that the covering member is a light-transmitting member provided with a light-reflecting material, because the diffused reflection effect on the surface thereof is enhanced and the loss of light is small.

In addition, as described above, the light incident on the light transmitting member 20 from the light emitting element 10 or the light source section composed of the light emitting element 10 and the wavelength converting member 40 passes through the light reflecting coating member 30 to one of the light source sections. Since the light is substantially limited to the incident region 80 by embedding the portion, the light hardly enters the light transmitting member 20 directly from the reflecting region 90, and the light emitting region is turned into a point light source with respect to the light transmitting member 20. can get closer. As a result, light reflection on the light-emitting side surface 21 of the light-transmitting member of the optical element having a convex curved surface can be reduced, and the entire device can be made smaller and thinner while maintaining high light extraction efficiency. becomes. As described above, the light-emitting device of the present invention has an incident area 80 that couples a light source section into the light-transmitting member 20 with high efficiency, and light components in the light-transmitting member. and a reflective area 90 that reflects light toward the light-emitting side surface 21. Due to the different actions thereof, the light extraction efficiency can be significantly improved in response to various shapes of the light-emitting side surface 21 of the light transmitting member 20. can be improved.

In particular, in Embodiment 1, the surface of the light transmitting member 20 on the light incident side is directly connected to the light source section, that is, the first surface of the wavelength conversion member 40 and the surface of the covering member 30 outside thereof. They are bonded, ie, the incident region 80 is provided at the interface with the first surface and the reflective region 90 is provided at the interface with the surface of the covering member 30, respectively. Therefore, the return light reaching the reflection region 90 can be reflected or scattered by the surface of the light-reflective coating member 30, transmitted through the light-emitting surface 21, and extracted to the outside of the device. In particular, as will be described later, when the covering member is a light-transmitting member containing a light-reflecting material, such as a light-transmitting resin, interface reflection with the light-transmitting member can occur on the surface of the covering member. Since the light that has entered the interior is reflected and scattered by the light-reflecting material, the effect of the reflective region 90 is enhanced, resulting in a light-emitting device with excellent light-emitting characteristics. The light-emitting device 100 of the first embodiment is manufactured by manufacturing the surface-emitting type light source section as described later, and then molding the light-transmitting member 20 directly onto the light-transmitting member 20 by various molding techniques. This is the mode that is most excellent in mass productivity as compared with the light-emitting devices of other embodiments described later.

Also, as shown in the drawing, the incident region 80 preferably protrudes toward the light emitting side from the reflective region 90 . As a result, the light is not blocked by the surface of the covering member 30, and furthermore, as shown in the figure, if the reflecting area 90 is formed as an inclined surface inclined from the reflecting area toward the projected incident area 80, that is, an inclined surface reflecting outward, The light emitted to the side of the light transmitting member 20 by the reflective area 90, that is, the high angle component from the light emitting device is increased, and a wide orientation is obtained.

(optical element and light source)
The relationship between the diameter W of the light transmitting member 20 in the present invention, that is, the optical element, the radius of curvature r of the convex surface, and the diameter L of the incident region 80 will be described in detail below. FIG. 3 is a schematic cross-sectional view showing the structure of each light-emitting device in the theoretical calculation model studied here. The light-emitting device 110 shown in FIG. 3A includes a rectangular parallelepiped (plate-shaped) light source unit 16 having a square with a side length L and a thickness of 100 μm. Further, the light source part exposes only its top surface, and its side and bottom surfaces are covered with the coating member 31, and the reflectance of the coating member 31 is set to 100%. A hemispherical light transmission member 20a having a diameter R whose center of curvature is the center of the upper surface of the light source indicated by a black circle in the drawing is provided on the surfaces of the light source and the covering member on the same surface. The light transmitting member has a diameter R and a diameter W of 4 mm (curvature radius of 2 mm) and a refractive index of 1.537. This light-emitting device 110 assumes the light-emitting device 100 of the first embodiment described above. In addition, the light-emitting device 120 shown in FIG. 3B has a gap 86 between the surface of the light-transmitting member 20b and the surface of the covering member 32, and the two surfaces are separated from each other. Similar to device 110 . More specifically, there is an inclined surface 94 inclined downward from the upper surface of the light source unit facing the flat surface (reflection area) of the light transmitting member 20b outside the light source unit 16, and the refractive index of the air in the gap 86 is is 1.000. This light-emitting device 120 assumes the light-emitting device 200 of Embodiment 2, which will be described later.

A light emitting device 130 shown in FIG. 3C is the same as the light emitting device 110 except that the light source section 16 is provided on the surface of the covering member 33, and the light source section is embedded in the light transmitting member 20c. The center of curvature is positioned at the center of the bottom surface of the light source section 16 as indicated by the black circle in the figure. Furthermore, in the light-emitting device 140 shown in FIG. 3D, the surface on which the light-transmitting member is provided is provided with the coating member 34 and the base material 35 with low reflectance outside thereof, and the light-transmitting member 20d is changed. Other than that, it is the same as the light emitting device 110 . More specifically, the coating member 34 has a reflectance of 100% as in other devices, and is a square with a side of 2.7 mm when viewed from above. It constitutes the entire region of the light transmitting member. The light transmitting member 20d is a spherical surface with a radius of curvature of 3 mm, the center of curvature of which is 2 mm away from the center of the upper surface of the light source section, and a diameter W of about 4.472 mm. Therefore, the light-emitting device 140 has a 100% reflectance region of the coating member 34 outside the incident region and a 90% reflectance region of the base material 35 outside the incident region on the surface of the light-incident side of the light-transmitting member. , and the surface on the light source side is a flattened hemispherical surface.

Based on the light emitting devices 110, 120, 130, and 140 described above, the ratio (L /R, L/W) and the light extraction efficiency are analyzed by theoretical calculation for each model. FIG. 4 shows the results of the analysis. Models A to C are the devices 110 to 130, model AD is a model in which the coating member 31 of the device 110 is replaced with the coating member 34 and the substrate 35 of the device 140, and models DD and DD. -W is the apparatus 140 and its L/W ratio, and models DA and DA-W are models in which the coating member 34 and the base material 35 are replaced with the coating member 31 of the apparatus 110 in the apparatus 140 and its L/W ratio. /W ratio, respectively, and the diameter L of the light source unit 16 is changed. As shown in FIG. 4, in the light-emitting devices of Models A to C, AD, DD-W, and DA-W, the L/R ratio (the L/W ratio for Models DD-W and DA-W) is 0.5. As it becomes larger, the light extraction efficiency begins to decrease, and this is particularly noticeable in Models A to C and AD. This indicates that in the range of 0.5 or less, the light extraction efficiency of the light source section can be close to that of a point light source with respect to the light-emitting side surface of the light-transmitting member having a hemispherical convex curved surface. Further, when comparing Models A to C, Models A and B significantly suppress the decrease in light extraction efficiency even in a region where L/R is large, compared to Model C of the comparative example. It can be seen that the structure in which a part is covered with a light-reflecting covering member is superior in miniaturizing the device while maintaining high luminous efficiency. In addition, in the model AD of the comparative example, the efficiency is lower than that of the models A to C even in a region where the light source is small. should be made sufficiently small, and the light transmission member should be made sufficiently large.

Furthermore, the light extraction efficiency of models DA and DD using the light transmitting member 20d of the light emitting device 140 is higher than that of the models A to C and AD using the light transmitting members 20a to 20c of the other light emitting devices 110 to 130. , its initial and maximum values are significantly lower. From the viewpoint of light extraction efficiency, it is most preferable that the shape of the surface of the light transmitting member on the light emitting side is hemispherical, but the size of the device increases. On the other hand, in the light emitting device 140 (models DA, DD) having the flat member 20d with a hemispherical surface, the light reflection component on the inner surface of the light transmitting member 20d increases and the efficiency decreases, but the size and thickness of the device are excellent. . Comparing the models DA and DD, the efficiency of the model DA tends to be superior to that of the model DD (apparatus 140) of the comparative example. I know it can be done. The models AD and DD having the low reflectance region 35 at the outer edge of the light incident side surface of the light transmitting member 20, like the light emitting device 140, are comparative examples. A structure is envisioned in which the members in the device lower than the cover member such as 51 are exposed. Therefore, in this model, due to the miniaturization of the device and the increase in the area of the light source, the light reflection on the inner surface increases, the amount of light reaching the low reflectance region that constitutes the annular outer edge increases, and the light extraction efficiency increases. will decrease. The light-transmitting member of the present invention may be a flat hemispherical surface, a flat convex curved surface with a different curvature, or various optical lens shapes as shown in FIGS. 9(b) and 9(c). As a result, even with a structure in which internal reflection of the light transmitting member increases, high luminous efficiency can be obtained, and the high efficiency can be maintained to reduce the size and thickness of the device.

Next, each constituent member and structure of the light emitting device of the present invention will be described in detail below.

(light emitting element)
The light-emitting element 10 can be a known one, specifically a semiconductor light-emitting element. Particularly, a GaN-based semiconductor is preferable because it can emit short-wavelength visible light and ultraviolet light that can efficiently excite fluorescent substances. A specific emission peak wavelength is 240 nm or more and 560 nm or less, preferably 380 nm or more and 470 nm or less. In addition, ZnSe-based, InGaAs-based, and AlInGaP-based semiconductor light-emitting elements may be used.

(Light emitting element structure)
As shown in FIG. 5, a light emitting device structure 11 made of semiconductor layers is composed of at least a first conductivity type (n-type) layer 2 and a second conductivity type (p-type) layer 3, with an active layer 3 interposed therebetween. A structure having In addition, the electrode structure is preferably a same-surface side electrode structure in which both the electrodes 6 and 7 of the first conductivity type and the second conductivity type are provided on one main surface side. may be provided in a counter electrode structure. As for the mounting form of the light emitting element 10, for example, in the same-surface side electrode structure, flip-chip mounting, in which the electrode-formed surface is used as the mounting surface and the substrate 1 side opposite to the mounting surface is used as the main output surface, is the output surface and the light-transmitting member. 20 is preferable in terms of optical connection. In addition, the electrode forming surface side is used as the main emission surface, and there are mounting methods in which a translucent member and a wavelength conversion member are combined on the surface, face-up mounting, and a translucent member with a wiring structure and a flip to the wavelength conversion member. Chip mounting and connection between the light transmitting member and the mounting substrate with the counter electrode structure described above are possible. Preferably, the light emitting element, the light transmitting member, and the wavelength converting member are not provided with wiring or electrodes. The growth substrate 1 of the semiconductor layer 11 may be removed if it does not form the light emitting device structure, and the semiconductor layer from which the growth substrate has been removed is covered with a supporting substrate, such as a conductive substrate or another translucent material. A structure in which a member and a substrate are bonded can also be used. A translucent member or wavelength conversion member 20 may be used as the supporting substrate, or an element having a structure in which a semiconductor layer is adhered/covered and supported by a translucent member such as glass or resin may be used. Removal of the growth substrate can be performed by peeling, polishing, or LLO (Laser Lift Off), for example, mounted or held on a support, device, or submount. Further, the light emitting element 10 can have a light reflecting structure. The light reflecting side (lower side in FIG. 1) can be provided with a light reflecting structure in the semiconductor layer, electrodes, or the like on the light reflecting side. As an example of the light reflection structure, a structure in which a multilayer film reflection layer is provided in the semiconductor layer, or an electrode and a reflection layer having a highly light-reflecting metal film such as Ag or Al or a dielectric multilayer film is provided on the semiconductor layer. structure.

(Nitride semiconductor light-emitting device)
As an example of the light emitting device 10, in the nitride semiconductor light emitting device 10 shown in FIG. , and a p-type semiconductor layer, which is the second nitride semiconductor layer 4, are epitaxially grown in this order. Then, a part of the n-type layer 2 is exposed to form an n-type pad electrode as a first electrode 7, and a translucent conductive layer 5 such as ITO is formed on almost the entire surface of the p-type layer 4, and a second electrode. 6, a p-type pad electrode is formed. Furthermore, a protective film 8 is provided by exposing the surfaces of the n-type and p-type pad electrodes 6 and 7 and covering the semiconductor layer. Note that the n-type pad electrode 7 may be formed via a light-transmitting conductive layer as in the case of the p-type. The growth substrate 1 is C-plane sapphire, R-plane, A-plane, insulating substrate such as spinel (MgAl ₂ O ₄ ), silicon carbide (6H, 4H, 3C), Si, ZnS, ZnO, GaAs. , conductive substrates of semiconductors such as GaN and AlN. Examples of _nitride semiconductors include a general formula of _{InxAlyGa1 -xyN} (0≤x, 0≤y, x+y≤1), as well as mixed crystals of B, P, and As. Further, the n-type and p-type semiconductor layers 2 and 4 are not particularly limited to a single layer or multiple layers, and the active layer 3 preferably has a single (SQW) or multiple quantum well structure (MQW). As an example of the device structure 11 for emitting blue light, an n-type semiconductor layer, such as Si-doped GaN, is formed on a sapphire substrate via an underlying layer of a nitride semiconductor such as a buffer layer, such as a low temperature growth thin film GaN and a GaN layer. and an n-type multilayer film layer of GaN/InGaN are laminated, followed by an active layer of MQW of InGaN/GaN, and further a p-type semiconductor layer of, for example, a Mg-doped InGaN/AlGaN p-type multilayer film layer and a p-type contact layer of Mg-doped GaN are laminated.

(Wavelength conversion member)
The light emitting device 100 of FIG. 1 includes a wavelength converting member 40 which is excited by the light from the light emitting element 10 in the light source section and capable of wavelength converting at least part of the incident light. The light source section may be configured by adding a light-emitting element or a light-transmitting member bonded thereto, and preferably a wavelength conversion member is used as the light-transmitting member. In this specification, even when the term "wavelength conversion member" is simply used, it can be applied by replacing it with a translucent member when it does not depend on the wavelength conversion function. As a result, the primary light emitted from the light emitting element 10 in the light source section is excited by the wavelength conversion member 40, whereby secondary light having a wavelength different from the emission wavelength of the light emitting element 10 is obtained. Color mixing of wavelength-converted secondary light provides a composite light source capable of realizing emitted light having a desired hue. In addition, a light source unit that emits converted light (single color, mixed color light) of an ultraviolet light emitting LED in a form that transmits almost only the secondary light excited by the primary light or its secondary light, may be a light emitting device.

Moreover, the wavelength conversion member 40 of FIG. 1 is configured to include the light emitting element 10 in plan view from the first surface side. In other words, as shown in FIG. 1 , the side surface of the wavelength conversion member 40 protrudes outward from the side surface of the light emitting element 10 . As a result, the light emitted from the light emitting element 10 is directly coupled with the light receiving surface wider than the upper surface of the light emitting element 10, so that the loss of the luminous flux is small. The amount of protrusion of the side surface of the wavelength conversion member 40 with respect to the side surface of the light emitting element 10 is, for example, 3% or more and 30% or less, more specifically 5% or more and 15% or less, relative to the dimension of the light emitting element 10. be. As an example, in the light-emitting device of Example 2 below, it protrudes with a width of about 50 μm from the end of the wavelength conversion member 40 .

The shape of the wavelength conversion member 40 is not particularly limited, but in the first embodiment, it is a plate-like body, which has good coupling efficiency with the emission surface of the planar light emitting element 10, and can be easily aligned so as to be substantially parallel to each other. preferable. In addition, by making the thickness substantially constant, the ratio of color mixture can be stabilized, and color unevenness can be suppressed in the incidence area 80 on the surface of the light source section. In addition, it is easy to bond a plurality of light emitting elements 10 to one wavelength conversion member 40, and the distribution of luminance and chromaticity on the emission surface of the light source section depends on the arrangement of the light emitting elements, but it can be suppressed. The thickness of the wavelength conversion member 40 is preferably 10 μm or more and 500 μm or less, more preferably 50 μm or more and 300 μm or less, in terms of luminous efficiency and chromaticity adjustment. The number of light-emitting elements 10 to be mounted on one light-transmitting member or wavelength conversion member 40 is not particularly limited. preferable. In the case of using a plurality of them, they may be arranged in a line, arranged at regular intervals at lattice positions, or the like.

Here, as the material of the translucent member used in the light source and serving as the base material of the wavelength conversion member 40, the same material as that of the coating member 30 described below can be used. can be used. In addition, molded bodies, crystals, and the like of the following phosphors may also be used. Specifically, the wavelength conversion member 40 includes a glass plate including a wavelength conversion member, or a phosphor crystal or a single crystal, polycrystal, amorphous body, or ceramic body having a phosphor crystal or its phase. In addition, sintered bodies, agglomerates, and porous bodies of phosphor crystal grains and optionally added light-transmitting members, and those obtained by mixing or impregnating them with light-transmitting members such as light-transmitting resins, or It is composed of a light-transmitting member containing phosphor particles, for example, a molded body of a light-transmitting resin.

The wavelength conversion member can be suitably combined with a blue light emitting element to emit white light. A typical phosphor used for the wavelength conversion member is a YAG phosphor (yttrium, aluminum, garnet) and _LAG -based phosphors ( _{lutetium , aluminum , garnet} ) _. : Ce (0≤x<1, 0≤y≤1, where Re is at least one element selected from the group consisting of Y, Gd, La and Lu), and the like are preferable. A phosphor containing at least one selected from the group consisting of YAG, LAG, BAM, BAM:Mn, (Zn, Cd)Zn:Cu, CCA, SCA, SCESN, SESN, CESN, CASBN and _CaAlSiN3 :Eu can be used. In addition to the light-transmitting member, the wavelength converting member may also be provided, for example, in the light-transmitting member, between the light-transmitting member and the light emitting element, in the adhesive interposed therebetween, and between the light emitting element and the covering member. can also It is also possible to increase the reddish component by using a nitride-based phosphor or the like that emits yellow to red light, and to realize lighting with a high general color rendering index Ra, a warm-white LED, or the like. Specifically, by adjusting the amount of phosphors with different chromaticity points on the CIE chromaticity diagram according to the emission wavelength of the light emitting element and containing can be made to emit light. In addition, nitride phosphors, oxynitride phosphors, and silicate phosphors that convert near-ultraviolet to visible light into yellow to red regions can be used. Examples thereof include _L2SiO4 :Eu (L is an alkaline earth metal ₎ , particularly ( _{SrxMae1 -x ) 2SiO4} :Eu (Mae is an alkaline earth metal such as Ca and Ba). Nitride-based phosphors and oxynitride (oxynitride) phosphors include Sr--Ca--Si--N:Eu, Ca--Si--N:Eu, Sr--Si--N:Eu, Sr--Ca--Si --ON: Eu, Ca--Si--ON: Eu, Sr--Si--ON: Eu, and the like, and the alkaline earth silicon nitride phosphor has the general formula LSi ₂ O ₂ N ₂ :Eu _{, general formula LxSiyN(2/3x+4/3y): Eu or LxSiyOzN ( 2 / 3x +4/3y-2/3z) :} Eu (L is Sr, Ca, either Sr or Ca).

(coating member)
As shown in FIG. 1, the covering member 30 covers a part of the light source section and the surface of the light transmitting member, and more specifically covers at least the light source section including the light emitting element so as to embed the light source section, and additionally transmits the light. The coating extends to the incident side surface of the member. Furthermore, a part of the wavelength conversion member 40 in the light source section, specifically, the side surface thereof, is covered, and the exposed surface of the light source section becomes an emission surface and enters the light transmission member. As the base material of the covering member 30, it is preferable to use a resin material, a silicone resin composition, a modified silicone resin composition, etc., which has good translucency, but an epoxy resin composition and a modified epoxy resin composition. , an insulating resin composition having translucency such as an acrylic resin composition can be used. In addition, a sealing member having excellent weather resistance, such as a hybrid resin containing at least one of these resins, can also be used. , glass, silica gel, and other inorganic substances having excellent light resistance can also be used. Furthermore, it is preferable that the covering member 30 is made of a highly heat-resistant resin molded body because it can cope with the heat generation of the light emitting element of the light source section and the wavelength converting member 40 . In Embodiment 1, a silicone resin is used as the base material constituting the covering member 30 . Silicone resin has excellent heat resistance, water repellency, and electrical insulation, and also has the advantage of being resistant to deterioration over time. Furthermore, the surface of the covering member 30 can be formed into a desired shape, such as an inclined surface or a curved surface as shown in the figure, to enhance the function and effect of the reflective area, control directivity and color distribution, and condense light. By appropriately combining with the optical function of the light transmitting member, the light emission characteristics of the device can be controlled.

Also, the covering member 30 contains at least one type of light reflecting material 35 in the base material. By containing a light-reflecting material, the reflectance of the coated member is increased, and more preferably, by using low-absorbing particles, light absorption and loss are reduced, and a coated member with light scattering properties can be obtained. Specifically, translucent particles are used. This light reflective material is one oxide selected from the group consisting of Ti, Zr, Nb, Al and Si, or at least one of AlN and MgF, specifically TiO ₂ and ZrO _{2 .} , Nb ₂ O ₅ , Al ₂ O ₃ , MgF, AlN, and SiO ₂ . The particles of the light reflective material are one kind of oxide selected from the group consisting of Ti, Zr, Nb, Al, so that the material can have high reflectivity and low absorption, and the substrate, especially the light-transmitting It is preferable because the difference in refractive index with respect to the flexible resin can be increased. In addition, the covering member can also be composed of a molded body made of the above-mentioned light-reflecting material. In addition, a molded body obtained by a sol-gel method may be used, which is preferable because the refractive index difference between the light-reflecting material and the air in the porous material can be increased to improve the light reflectivity, and the body can be composed of an inorganic material. On the other hand, a covering member having a base material such as the above-mentioned resin can be molded into a desired shape and controllability of the covering area, and can improve sealing performance and airtightness performance. preferable. In addition, considering the characteristics of both coating members, a composite molded body of both can be formed. For example, a part of the porous molded body is impregnated with a resin on the outer surface side, and It can have a porous structure. As described above, the covering member or the surrounding body that surrounds the light source section may be such that the inner region and the outside are communicated with each other, or it may be gas-permeable. .

In the covering member 30 containing the light-reflecting material 35 in the base material described above, since the depth at which light leaks differs depending on the content concentration and density, the concentration and density are appropriately adjusted according to the shape and size of the light-emitting device. should be adjusted. For example, to reduce the thickness of a relatively small light-emitting device, it is preferable to have a high concentration of light-reflecting material. On the other hand, the concentration and particle size can be appropriately adjusted so as to be suitable for the preparation of the raw material of the coated member containing the light-reflecting material, coating of the raw material, molding, etc., and the particle size is similar to that of conventional fillers. can be used, and the same applies to the porous body. As an example, it is preferable that the concentration of the light reflecting material 35 is 20% by weight or more, and the thickness of the covering member 30 is 20 μm or more. Within this range, productivity is good, and emitted light with high brightness and high directivity can be obtained from the first surface, which is the light emitting surface. Furthermore, other fillers may be added to the resin base material. For example, a heat conductive material can be added, heat generated by the light source can be efficiently diffused, reliability can be improved, and output can be increased. Specifically, a thermal conductivity of 0.8 W/K·m or more is preferable as the thermally conductive material. These may be mixed and contained. It is also possible to mix pigments and the like to color the material and absorb light of a specific wavelength.

The area covered by the covering member is as described above, and will be described in detail below. By covering the side surface of the light source part and the side surface of the wavelength conversion member, it is possible to prevent the leakage of light from the side surface and further suppress the emission of light to the outside from the side surface, thereby reducing color unevenness in the overall emission color. and luminance unevenness can be reduced. In addition, a part of the light source is exposed, and more specifically, the side surface of the light emitting element, the wavelength conversion member, and other members is covered and the upper surface is exposed. It can increase the brightness at the output surface. Furthermore, the heat generated by the light source section, particularly the wavelength conversion member, is conducted to the covering member 30, so that the heat dissipation can be enhanced as compared with the case where the covering is not provided. Moreover, in addition to the side surface of the wavelength conversion member 40, it is preferable to cover a part of the light emitting element side surface (second surface). Specifically, as shown in FIGS. 50 and the covering member 30 is filled to cover the periphery of the light emitting element 10 with the covering member 30 . In other words, on the second surface, the exposed region other than the facing region to be bonded to the light emitting element 10 is covered. In this manner, the second surface is provided with the optical connection region and the covering region of the covering member 30, and the side surface of the light emitting element is covered by extending from the covering region, so that the connection region has a primary Light can be guided with high efficiency, and light absorption in the substrate 50 can be suppressed by reflecting the light in the wavelength conversion member on the second surface side. Furthermore, when a plurality of light emitting elements 10 are bonded, the above-mentioned problem becomes more serious in adjacent elements. By coating with, the above effect is obtained, which is preferable.

In the light-emitting device of the present invention, the exposed surface side of the covering member 30 forms the periphery of the first surface (output surface) of the light source section, and has a structure in which the reflecting area of the light transmitting member and the opposing area are formed. Various forms can be adopted for the other exposed surface areas and the inner side. For example, the covering member 30 may cover the side surface of the wavelength conversion member 40 to form an exposed surface, and the side surface of the light source section on the inner side or the periphery thereof may be in contact or spaced apart and surrounded. A covering member is provided in contact with or spaced apart from the light emitting element. As shown in the figure, it is preferable from the viewpoint of manufacturing that the light source section is embedded by continuously encapsulating the light emitting element 10 from the side surface and the second surface of the wavelength conversion member. On the other hand, in addition to such contact on the inner side, the covering member 30 can also be arranged on the outside of the side surface of the light emitting element 10 with a gap therebetween, so that the interface with the gap is formed. It is preferable because reflection can be realized and deterioration of the coating member made of resin or the like due to light and heat can be prevented. Furthermore, a structure in which the gaps are provided in the spaced regions of the plurality of light emitting elements 10 can be employed. At this time, it is preferable to form an exposed portion having a high refractive index difference with the air/gas in the internal space of the gap so as to preferably increase the refractive index difference with the light emitting element 10 .

In the present invention, the light-transmitting member has a reflective area on the light-incident side surface outside the incident area of the light source section, and the reflective area is provided on the surface of the light-transmitting member and further on the interface with the covering member. The reflection function greatly depends on the material and surface form of each member. In Embodiment 1, by being formed at the interface between the covering member containing the light reflecting material and the light transmitting member molded thereon, suitable reflecting and scattering functions are provided. Specifically, since both materials are translucent materials, an interface between the translucent materials is formed, a high reflectance is obtained, and a scattering function is imparted by the light-reflecting material in the covering member. be. As a result, the light extraction efficiency can be improved, and the brightness and color unevenness can be improved. The effect increases when flattened. At this time, it is particularly preferable that each member constituting the interface has a refractive index difference. If the larger refractive index is on the side of the light-transmitting member, the reflectance at the interface of the light-transmitting material is improved, and the output of the device is improved. More preferably, it is on the side of the covering member because a large amount of light is taken into the inside and scattered, so that it is superior in orientation and luminance/chromaticity distribution. Therefore, not only the function of the optical element of the light transmission member described above, the interface between the two members described later, the shape of the reflecting surface, but also the materials and compositions of the two members, as well as the concentration and distribution of the reflective material in the covering member, are adjusted. Also by doing so, the light emission characteristics of the light emitting device of the present invention can be appropriately controlled. In particular, when the wavelength conversion member is included in the light source, the chromaticity and luminance distribution of the emitted light from the light source will be peculiar due to the properties of the member such as its shape. preferable. Furthermore, since both members are made of resin, the interface between the resins can be formed in a desired shape, and as will be described later, it is possible to design devices with various luminous properties such as directivity.

As described above, the light-emitting device of the present invention has two regions surrounding a light source, one of which is a light-guiding region having a light-emitting surface on the side of a light-transmitting member, and the other of which is a light-guiding region on the side of a covering member. It is a covered area with a high reflectance, and furthermore, the light source part has a structure in which an incident area whose emission surface is exposed from the covered area and coupled to the light guide area and a reflection area provided at the boundary between the light guide and the covered area. ing. By surrounding the light source unit with these two regions and providing an incident region and a reflection region at the junction or boundary region, the above-described functions and effects are appropriately expressed, controlled, and desired light emission characteristics, A light-emitting device that can be miniaturized can be obtained. In particular, it is preferable that the emission surface of the light source section is a surface light source and that the incidence area is planar, so that the reflection areas of the boundary portions that are continuous with it can function in cooperation with each other. On the other hand, as will be seen in the discussion of device 140, models DD and DA, to be described later, it is preferred that the coverage area is well formed, ie, located at the boundary of two areas. For example, the outer edge of the light transmitting member, which is wider than the covering member, faces the mounting substrate exposed from the covering member and provides a boundary, which greatly affects the characteristics of the device due to the substrate surface with low reflectance. In another example, if light leaks from the light source unit or a path for the light leaks from the light source unit is provided on the side surface or mounting surface of the light source unit, the amount of light is large, which greatly affects the output and efficiency. For example, the side surface of the light emitting element and the surface (substrate side, mounting side) facing the incident area are exposed from the covering member, and a surface such as a substrate surface having a lower reflectance and a higher light absorption than the covering member is exposed there. As a result, the effect becomes more pronounced. Therefore, it is preferable to cover the periphery of the light source or to cover the exposed surface of low reflectance and high absorbance, preferably both. The form filled with is a structure with both. Accordingly, it is preferable that the covering area is provided so as to face substantially the entire area of the light guiding area, and that the surface of the covering member includes the light incident side surface of the light transmitting member. Areas other than the exit surface are preferably covered. Specifically, as shown in the figure, a covering member is provided as an underfill on the opposite surface side of the light emitting element, and a structure having both is provided. It has a structure that prevents the exposure of the substrate surface and the formation of a light leakage path from the light source. Therefore, the surface of the light source unit facing the emission side is included by the covering member and the covering area. Preferably separated.

The reflective surfaces provided at the boundary between the light guide region and the covering region are provided on the surfaces facing each other in each region, and are provided at the interface when the two are joined together as in the first embodiment. In the former, when the light transmitting member and the covering member face each other while being separated from each other as in the second embodiment, the opposing surfaces of the light transmitting member and the covering member are provided with a reflective function and overlapped, resulting in high light extraction efficiency. In the latter, since the boundary region and the interface between members have a reflecting function, the directivity can be easily controlled. Therefore, the reflective surface can have a desired reflective function in molding each region and each member. On the other hand, when the reflecting surface is tilted outward as in the second embodiment, for example, when the normal direction is tilted outward with respect to the optical axis of the light source, the directivity is wide, and conversely tilted inward. In this case, high luminance light emission is obtained, which is preferable. In addition, it is possible to obtain desired light emission characteristics by providing various optical surfaces such as convex curved surfaces and concave curved surfaces. Each opposing surface of the member can have a different reflection function, and when both are joined, the above-mentioned interface reflection and internal scattering function can be imparted, and when both are separated, diffused reflection on the surface of the covering member facilitates light extraction. Structure and can. As described above, the coating region, the reflectance of the coating member, for example, the concentration of the light-reflecting material may be constant as in the embodiments and examples, or different regions may be provided or distributed. You can As a result, a different reflection function can be imparted to each region and site. For example, the density of the light reflecting material can be changed between the inner region on the light source side and the outer region on the outer side, or each region can be covered with a coating member having a different density. It can be formed into different scattering light emitting devices in the inner and outer regions. For example, the outer region can be made of a high-concentration light-reflecting material to increase the scattering properties and reduce the color unevenness of the outer edge portion of the emitted light.

(Light transmission member)
The light transmission member 20 may be bonded to the first surface of the light emitting device 10 or the first surface of the wavelength conversion member 40 to improve light extraction efficiency. The light-transmitting member 20 has at least a light-emitting surface 21 and a light-incident surface, and the light-emitting surface 21 can be formed in various shapes depending on the purpose. For example, as described above, by forming the light-emitting side surface 21 into a convex curved, spherical (hemispherical) convex lens shape, it is possible to achieve uniform transmission characteristics (critical angle) for light incident at all azimuth angles. can be efficiently extracted to the outside. Further, the angle of radiation of light can be made smaller than that of a spherical surface by using a desired curvature and a convex lens shape, for example, a cannonball shape, without being limited to a spherical surface. In addition, the light may be diffused by forming a concave curved surface or a concave lens shape, or an optical element having a desired directivity as described in Embodiment 4 and FIG. 9 may be used.

The light transmitting member 20 is formed using a resin material such as epoxy resin, silicone resin, modified silicone resin, urea resin, urethane resin, acrylic resin, polycarbonate resin, or polyimide resin, like the base material of the coating member 30. can do. Since the light transmitting member 20 also serves as a sealing material for protecting the light emitting element 10 and the wavelength conversion member 40, a material having excellent weather resistance, heat resistance, and hardness is preferable, such as an epoxy resin or a hard silicone resin. is preferable, and glass may be used. Furthermore, the light transmitting member 20 is appropriately added with the above-described phosphor, and/or the above-described light scattering particles such as TiO ₂ , and/or the above-described filler such as quartz glass, and the above-described pigment. Desired light emission characteristics can be obtained, and the same applies to translucent resin materials such as the translucent member and the adhesive 15 . Also, the light transmitting member 20 can be molded into a desired size and desired shape as described above by compression molding, transfer molding, or the like.

(Mounting board)
On the other hand, in the light-emitting device 100 of FIG. 1, the substrate 50 on which the light-emitting element 10 is mounted may be formed with wiring 51 connected to the electrodes of the element at least on its surface, and wiring 52 for external connection may be used. (FIGS. 7 and 9) or the like may be provided. The material of the substrate is, for example, aluminum nitride (AlN), which includes single crystal, polycrystal, sintered substrates, ceramics such as alumina, glass, semimetals such as Si, metal substrates, and laminates thereof. Solids and composites can be used, and metals and ceramics are preferred because of their high heat dissipation. Note that the substrate 50 may have no wiring. For example, the device shown in FIG. It's okay. Further, as in the illustrated light emitting device, the covering member 30 may be provided on the mounting substrate 50, or may also cover the outer side surface of the mounting substrate 50. FIG. Moreover, it is preferable that at least the surface of the mounting board 50 is made of a highly reflective material. As shown in FIGS. 1 and 2, the light emitting element 10 is adhered onto the wiring 51 by the conductive adhesive 60 and electrically connected to the outside. Solder, Ag paste, Au bump, or the like can be used as the conductive adhesive material 60 .

(Frame, laminated substrate, base material)
The light emitting device 100 shown in FIG. 1 has a frame 55 and is a holding member for the covering member 30 . The frame 55 can be made of ceramic, resin, or the like. Alumina, which has high light reflectivity, is preferable, but it is not limited to this as long as a reflective film is formed on the surface. If it is a resin, screen printing or the like may be used, or the molded body may be adhered to the mounting substrate. Moreover, it is preferable to increase the reflectance by using a light-reflecting material like the covering member 30 . Further, the frame body may be colored depending on the purpose in the same manner as the additional member. This frame can also be removed after the covering member is filled or molded. Further, the frame body may be formed integrally with the mounting substrate of the light-emitting element, such as the laminated substrate 56, the device base having a cavity structure with a base material, or the like.

(adhesive)
An adhesive 15 may be interposed at the interface between the light emitting element 10 and the wavelength conversion member 40 to fix the two members together. The adhesive 15 is preferably made of a material that can effectively guide the light emitted from the light emitting element 10 toward the wavelength conversion member 40 and that can optically connect both members. Examples of the material include the resin material used for each member described above, and as an example, a translucent adhesive material such as silicone resin is used. A similar translucent adhesive may be provided between other members on the optical path, such as the adhesive 55 in the second embodiment (FIG. 7).

(Method for manufacturing light-emitting device)
An example of a method for manufacturing the light emitting device 100 shown in FIG. 1 will be described below with reference to FIG. First, as shown in FIG. 6A, bumps 60 are formed on the substrate 58 or the light emitting element 10, and the light emitting element 10 is flip-chip mounted through the bumps. In this example, one LED chip is mounted side by side in each area corresponding to one light emitting device on the submount substrate 58 (however, the number of LED chips can be changed as appropriate). Next, the first surface side of the light emitting element 10 (the back surface of the sapphire substrate 1 or the exposed surface of the nitride semiconductor 11 if the substrate is removed) is coated with a silicone resin as an adhesive to attach the wavelength conversion member 40. Laminate. After that, the silicone resin is thermally cured to bond the light emitting element 10 and the wavelength conversion member 40 together. Further, a frame body 57 having a predetermined size and shape is erected around the light emitting element 10 . Here, the height of the frame 57 is lower than that of the first surface of the wavelength conversion member 40, but may be substantially the same or higher.

Next, a liquid resin 31 containing light-reflecting particles is potted in the frame 57 by a dispenser (quantitative liquid ejection device) 71 or the like so as to cover the side surface of the wavelength conversion member 40 . The dropped resin 36 crawls up the wall surface side of the light emitting element 10 by surface tension and covers the side surface of the wavelength conversion member 40 . Then, the resin 36 is cured to form the covering member 37 . Here, the coating member 37 has a concave portion formed on its surface at a position lower than the first surface of the wavelength conversion member 40. , and the surface of the covering member 37 is inclined at its periphery. Next, as shown in FIG. 6B, a suitable amount of liquid thermosetting resin 26, which will be a light transmitting member, is dropped onto the coating member 37 and the wavelength converting member 40 by using a similar dispenser or the like. Subsequently, as shown in FIG. 6(C), a predetermined pressure is applied from above by an upper mold 72 having a hemispherical lens mold to compress the resin layer 26, and the resin layer 26 is kept in that state for a predetermined time. While holding, the resin layer 26 is primarily cured. Here, it is preferable to set the heating temperature and heating time in the mold to such conditions that the resin reaches sufficient hardness to retain a predetermined shape. For example, the primary curing temperature is 100-170°C, preferably about 120-150°C. Also, the curing time is 200 to 900 seconds, preferably 250 to 600 seconds. Also, depending on the shape of the inner surface of the upper mold 72, a lens having a desired lens diameter and curvature radius can be formed.

Further, as shown in FIG. 6(D), the substrate provided with a series of light-emitting devices on which a resin molded body 27 having a desired lens shape is formed is taken out from the mold and heated under predetermined conditions to perform resin molding. The body 27 is secondarily cured. The conditions for the secondary curing are such that the temperature of the secondary curing is equal to or higher than that of the primary curing, and the time of the secondary curing is set to be longer than that of the primary curing so that the resin molding 27 is sufficiently cured. preferably. In the case of epoxy resins and hard silicone resins, the secondary curing time is about 3 to 5 hours. By sufficiently performing the secondary curing in this way, it is possible to prevent unreacted curing components from remaining in the resin molding 80 and adversely affecting the reliability of the light emitting device. In addition, the throughput of the process can be increased by performing the secondary curing after removing from the mold. Finally, dicing is performed at a predetermined position (for example, dotted line A in FIG. 6(D)), and the light-emitting device 100 of FIG. 1 is obtained by cutting into desired sizes and individualizing.

(Embodiment 2)
FIG. 7(a) is a schematic cross-sectional view of a light emitting device 200 according to Embodiment 2 of the present invention, and FIG. 7(b) is a schematic cross-sectional view for explaining the light source peripheral portion thereof. In the light-emitting device 200, the structure other than the light-transmitting member 20 is substantially the same as that of the first embodiment. This light-emitting device 200 has a configuration in which a light-transmitting member 20 preformed in a hemispherical shape with a diameter R (=W) is adhered to a first surface of a wavelength conversion member 40 via a light-transmitting adhesive 28 . ing. In this light-emitting device 200, an incident area 82 bonded to the adhesive 28 with a diameter L2 and a reflecting area 92 outside the incident area 82 are provided on the surface of the light transmitting member 20 on the light incident side. The reflective area 92 and the surface 93 of the covering member are separated from each other, and a gap 85 is provided between them. It is possible to improve the light extraction efficiency. As can be seen from the analysis results shown in FIG. 4, the light emitting device 200 according to the second embodiment has a higher light extraction efficiency than the light emitting device 100 according to the first embodiment. It is small and is an excellent configuration for small devices. It should be noted that the translucent adhesive 28 is preferably made of a material having substantially the same refractive index as that of the light transmissive member 20 to be bonded. This is to reduce the reflection of light at the interface between the light transmitting member 20 and the light transmitting adhesive 28 and improve the light coupling efficiency. You can easily do that.

In addition, in the intervening translucent adhesive 28, the area facing the incident area 82 on the light source side, that is, the surface on the light incident side, is connected to the first surface of the wavelength conversion member 40, which is the emission surface of the light source. An incident area 81 with a diameter L1 is provided at the interface, and a reflective area 91 is provided at the interface with the surface of the covering member. The diameter L2 is preferably larger than the diameter L1, so that light can be efficiently guided from the light source section to the light transmitting member 20. As shown in FIG. In addition, since the reflection area 91 is provided, the return light in the translucent adhesive can be reflected and scattered on the surface of the covering member, and the efficiency of light coupling to the light transmissive member 20 can be improved. It should be noted that depending on the range of the covering/joining area between the covering area (the light incident area 81 and the reflecting area 91) on the light source side of the translucent adhesive 28 and the reflecting area 93 of the covering member exposed from the adhesive, The ratio of the reflective regions 91 and 92 outside the light source section can be adjusted, and for example, substantially the entire region of the light incident side surface of the light transmitting member 20 may be covered with the light transmitting adhesive 28 . In this case, the space between the light-transmitting member and the covering member is filled with the light-transmitting adhesive to form a transparent region, and the transmission of light from the light-transmitting member 20 into the light-transmitting adhesive 28 is promoted. Similar to 1, the returned light is reflected by the reflective area 91 on the surface of the covering member and taken out to the outside. That is, the incident surface side 25 is separated from the emitting surface 81 of the light source unit and the covering member surface 93 with the translucent adhesive interposed therebetween, so that the light propagates within the separated area sandwiched between the respective surfaces. As a result, the light is reflected and scattered by the surface 93, and is also reflected by the reflective area 92 facing the surface 93, so that an efficient reflective structure can be achieved.

(Embodiment 3)
FIG. 8 is a schematic cross-sectional view for explaining the periphery of the light source section of the light emitting device according to Embodiment 3 of the present invention. Note that the structure around the light source portion of the light emitting device described here can also be applied to the structure of the light emitting device in other embodiments. The incident region 83 of the light transmitting member has an uneven structure, and the incident light from the light emitting element 10 and/or the wavelength converting member 40 of the light source section is scattered, and the return light can be reflected and scattered. The reflecting function of the region 90 is supplemented, the directivity of the emitted light from the light emitting surface can be widened, and uneven brightness and uneven color can be easily reduced. In particular, when a plurality of light-emitting elements 10 are mounted on one wavelength conversion member 40, the influence of the arrangement of each light-emitting element 10 and the resulting light distribution, luminance unevenness, and color unevenness are large, and this is reduced. Therefore, it is preferable. In addition, the uneven surface is expected to improve the optical coupling efficiency and the adhesion between the two members. Further, such an uneven structure can be provided not only on the surface of the wavelength conversion member, but also on the surface of the light emitting element side, and further on the surface of each member on the optical path to obtain the same effect. It may be provided in the boundary area with the transmission member or in the light source section, for example, on the surface of the substrate 1 on the semiconductor layer 11 side. The concave-convex structure such as the concave-convex surface 43 of the wavelength conversion member can be provided by polishing, dry etching, wet etching, or the like, and irregular concave-convex structures as well as regular pattern concave-convex structures can be formed.

In the light-emitting device shown in FIG. 8, the light-emitting element 10 has a structure in which a semiconductor element structure 11 having a plurality of light-emitting regions (light-emitting layers) separated from each other is provided on one growth substrate 1 . Thus, a plurality of light-emitting elements 10 can be mounted on one wavelength conversion member 40 by bonding a single light-emitting element and by forming the light-emitting element 10 with the light-emitting regions separated by integrating the growth substrate 1. Compared to the case, the influence of the arrangement and light distribution of each light emitting element 10 can be reduced. Furthermore, the wavelength conversion member 40 has a width smaller than the width of the first surface of the light emitting element 10 (the back surface of the growth substrate 1). It is located inside the 10 sides. In this form, the brightness can be relatively increased by narrowing the light emitting region, and the ratio of the color mixture of the primary light and the secondary light can be made uniform within the plane. If the side surface of the light emitting element 10 and the side surface of the light emitting element 10 are located substantially on the same plane, the amount of light from the light emitting element 10 is insufficient at the outer edge of the wavelength conversion member, and color unevenness tends to occur. can. However, the term “substantially the same surface” as used in this specification means that it is substantially the same surface in view of the above-mentioned function, and for example, it is about ±10% of the dimensions of the wavelength conversion member 40 and the light emitting element 10 . can do. Furthermore, in the light-emitting device shown in FIG. 8, the light-emitting element 10 and the wavelength conversion member 40 are directly bonded without using a translucent adhesive. Such bonding can be realized by surface activation, crystal bonding by thermocompression bonding, or the like. By not using an adhesive, which is a resin material with a relatively small refractive index, the number of interfaces with different refractive indexes is not increased, and the bonding efficiency is increased. In addition, the heat dissipation from the wavelength conversion member 40 can be improved.

(Embodiment 4)
9A, 9B, and 9C are schematic cross-sectional views of light emitting devices 300, 400, and 500, respectively, according to Embodiment 4 of the present invention. Embodiment 4 shows a modification of the shape of the light-transmitting member 20 and its light-emitting side surface in the light-emitting device according to the present invention, and can be applied to each embodiment, and other main structures. are substantially the same as those of the first embodiment, so the same reference numerals are assigned to the same configurations, and description thereof will be omitted as appropriate.

The shape of the light-emitting side surface 21 of the light transmitting member 20 in the light-emitting device 300 of the example shown in FIG. More specifically, as indicated by black circles in the drawing, the center of curvature is located at a position Y downward from the center of the surface of the wavelength conversion member 40, and the surface 21 has a diameter R (radius of curvature r=R/2), and its diameter (sectional width) W is W=2×(r ² −Y ² ) ^1/2 . By making the light-transmitting member 20 flat as in the device 140 described above, model D (DA), the size and thickness of the light-emitting device can be reduced. Light reflection on the inner surface of the transmissive member 20 is increased. However, in the light-emitting device of the present invention, most of the surface of the light-transmitting member 20 on the light incident side is occupied by the reflecting region 90 , so the light within the light-transmitting member is reflected there and further scattered by the light-reflecting material 35 . By doing so, it can be efficiently taken out to the outside. In the drawing, the covering member 30 has a cross-sectional width sufficiently wider than that of the light-transmitting member 20, but it goes without saying that the width of the covering member 30 can be reduced so that both ends are substantially the same. Moreover, the light emitting device 300 has a Zener diode electrically connected to the light emitting element 10 on the substrate 50 . The protective element 14 for electrically protecting the light emitting element is embedded in the covering member 30 as shown in the figure, and if it is separated from the light source section and the reflective area, it is optically protected from other main constituent members. and the diameter of the light emitting device and the covering member can be made substantially equal to the diameter of the light transmitting member. It is preferable because it does not hinder the conversion.

In the light emitting device 400 of the example shown in FIG. 9B, the shape of the light transmitting member 20 is composed of the upper surface 22 made up of two convex curved surfaces that intersect directly above the center of the wavelength converting member 40 and the side surfaces 23 thereof. The light emitted from the surface of the light source passes through the incident area 80, is reflected laterally using the upper surface 22 as the main reflecting surface, and is extracted to the outside of the device using the side surface 23 as the main light emitting surface. In order to enhance the reflection function, the upper surface 22 may be provided with a metal film, a dielectric multilayer film, or a reflective film or member such as a coating member containing the light reflective material 35 . Moreover, in such a light emitting device, the light extraction efficiency is enhanced by the reflection and scattering by the upper surface 22 and the reflective region 94, and the color unevenness of the light emitted from the wavelength conversion member 40 is alleviated. Moreover, the side surface of the wavelength conversion member 40 may be exposed from the covering member 30 thereby.

In the light-emitting device 500 of the example shown in FIG. 9C, the shape of the light-transmitting member 20 is composed of a flat upper surface 23 and a curved side surface 24 inclined toward the inner light source section. have. As a result, light emitted from the surface of the light source section passes through the incident area 80, is condensed upward by the side surface 24, and is taken out from the upper surface 23 to the outside of the apparatus. A similar reflective film may be formed on the side surface 24 as described for the light emitting device 400, and another frame may be formed on the frame 56 as indicated by the dotted line in the drawing. It is also possible to form a laminated structure of a second light reflecting layer covering the light transmitting member 20 by filling a covering member containing the light reflecting material 35 .

The above examples show application examples of the light-emitting device of the present invention to various light-transmitting members. An incident area of the light source section is provided inside thereof. In particular, in light-transmitting members having various shapes instead of a convex curved surface as in FIG. Other structures work well. Also, regarding the relationship between the diameter L of the light source portion and the diameter W of the light transmitting member, the relationship between the L/W ratio and the light extraction efficiency tends to become more pronounced, and the drop in efficiency tends to increase. it is conceivable that. Thus, the devices of FIGS. 9(b) and 9(c) have a structure in which, in addition to the reflection area facing the covering member on the incident surface side, reflection areas are also provided on the separate surfaces 22 and 24. Furthermore, the light emitting surface 23 is provided, and with this structure, suitable reflection and scattering by the coating member can be achieved in a part of the reflection area, particularly in the vicinity of the light source section, and a device with desired light emission characteristics can be realized.

(Embodiment 5)
FIG. 10 is a schematic cross-sectional view of a light emitting device 600 according to Embodiment 5 of the present invention. The same reference numerals are assigned to the same configurations, and the description thereof will be omitted as appropriate. In the light-emitting device of the present invention, the light source section is covered with a light-reflecting covering member 30 and optically coupled to the light-transmitting member. It can take various forms. A light-emitting device 600 of FIG. 9 is an example of such a structure. ing. A conductor 61 connected to each electrode of the light emitting element 10 is provided, and an external connection portion is formed to reach the rear surface side of the covering member 30 . The extension direction, exposure position, and surface of the conductor 61 can be changed as appropriate. The conductor 61 may have a columnar shape as shown in FIG. 9 or a combination of layered shapes. With such a light emitting device 600, the light source section such as the light emitting element 10 can be almost completely covered with the covering member 30 except for the incident region 80 of the light source section, and the light emitted from the light source section can be , the absorption and loss by the conductor wiring and the like can be reduced, and the light extraction efficiency from the light source section can be enhanced.

In such a device, for example, a light emitting element is placed on a support substrate, a coating member is applied to form a molded body, the surface is treated with a release agent or the like in advance, and the molded body is peeled off from the support substrate. It can be realized by a method of taking out the molding of the covering member in which the light source part is embedded. Other structures may be formed by molding or adhering the above-mentioned light-transmitting member before or after the molded body is peeled off, or may be cut into individual devices before and after the peeling, and a support substrate such as a mold may be provided. may be used to form the molded product on the light-transmitting member. In addition, the wiring structure of the light source part is placed so that the incident area 80 side surface faces the support substrate, and the electrode of the light emitting element and the conductor thereon are formed by film formation, plating, bumps, or the like. Then, the covering member may be formed, the wiring side surface is placed facing the support substrate, and the conductor or the wiring layer on the support substrate is preliminarily applied to the light emitting element side, the support substrate side, or both. A conductor combining them may be provided and separated.

Examples of the present invention will be described in detail below. It goes without saying that the present invention is not limited only to the examples shown below.

(Examples 1-3)
In the light emitting devices of Examples 1 to 3, the light emitting element 10 as shown in FIG. 7, or the element and the wavelength converting member 40 joined thereto are covered with a covering member, and the exposed light emitting surface of the upper surface of the light source part is covered. It has a structure in which a lens 20 is adhered to the top via an adhesive 28 . Specifically, one blue LED chip of approximately 1 mm×1 mm approximately square as the light emitting element 10 is flip-chip mounted on the wiring 51 of the AlN ceramics substrate 50 with the bumps 60 . In Example 1, the side surface of the LED chip is covered with a covering member 30 filled around the emission surface of the sapphire substrate surface, which is the growth substrate 1 of the LED 10, so that the emission surface is exposed. The covering member 30 is a silicone resin containing a light reflecting material 35, which is TiO ₂ microparticles having a particle size of about 270 nm, at a concentration of about 23 weight percent. In Examples 2 and 3, one sintered body of YAG, which is a plate-like wavelength conversion member 40, is bonded onto the growth substrate 1 of the LED 10 with a translucent adhesive 15 made of silicone resin. Then, as shown in the figure, a part of the bottom surface and side surfaces of the wavelength conversion member 40, the side surface of the LED chip, and the like are covered with the coating member 30, as in the first embodiment, in a state where the emission surface of the wavelength conversion member 40 is exposed. surface is encapsulated. The surface of the covering member 30 is inclined in the vicinity of the light source section so as to crawl up a side surface continuous from the emission surface of the light source section as shown in the drawing. The outer shape of the wavelength conversion member 40 is rectangular with dimensions of about 1.1 mm×1.1 mm in Example 2 and about 1.5 mm×1.5 mm in Example 3, and a thickness of about 150 μm. In each embodiment, on the surface of the covering member, the emitting surface of the light source part of the light emitting element 10 or the wavelength converting member 40 is included, and the optical axis is positioned substantially at the center thereof. A hemispherical lens-shaped light transmitting member 20 having a diameter R of about 4 mm is bonded to its exit surface with a light transmitting adhesive 28 made of the same silicone resin.

The ratio (L/R) of the diameter L of the light source portion to the diameter R of the light transmitting member 20 is about 0.250 in Example 1, about 0.275 in Example 2, and about 0.375 in Example 3. be. The blue monochromatic light emitting device of Example 1 emits light at a drive current of 350 mA, an emission peak wavelength of 449 nm, and an emission output of 522 mW. In addition, the white light emitting device of Example 2 has a luminous flux of 115 lm (chromaticity y value: 0.38) at a driving current of 350 mA, and a luminous flux of 170 lm (the same chromaticity y value) at a driving current of 550 mA, which is relatively high luminance. . The white light emitting device of Example 3 has a luminous flux of 135lm (chromaticity y value of 0.38) at a drive current of 350mA, and a luminous flux of 200lm (the same chromaticity y value) at a drive current of 550mA, which is a relatively high luminous flux.

(Examples 4-6)
Next, the influence of the presence or absence of the light transmission member 20 on the luminous efficiency will be verified by changing the configuration of the wavelength conversion member 40 . The light-emitting device of Example 4 is the same as that of Example 3, and the light-emitting devices of Examples 5 and 6 are different only in the configuration of the wavelength conversion member 40 of Example 4. Similar sheets _of YAG phosphor dispersed in silicone resin were used _. is a sheet. These resin sheets are prepared by spin-coating a phosphor-diffused resin onto a plate coated with a release agent, curing the resin, and cutting it into a predetermined size. FIG. 11 shows the difference in luminous efficiency depending on the presence or absence of the light transmission member 20 in the light emitting devices of Examples 4 to 6. FIG. In Examples 4, 5, and 6, D, E, and F indicate the positions after mounting the light-transmitting member 20, and d, e, and f indicate the positions before mounting the light-transmitting member 20, respectively. As shown in FIG. 11, in any embodiment, by mounting the light transmission member 20, it is possible to increase the efficiency of light emission with the same chromaticity, and it is confirmed that the light emission efficiency is improved.

When a sintered body is used as the wavelength conversion member 40, it may be difficult to produce the sintered body, the conversion efficiency may decrease, or the firing of two or more types of phosphors may be greatly restricted. be. On the other hand, a sheet produced by diffusing a phosphor in a resin can be produced regardless of the type of phosphor because the production temperature is low and the characteristics of the phosphor are not impaired. For example, as shown in FIG. 11, a resin sheet using a silicate phosphor exhibits a higher conversion efficiency than a sheet using a YAG phosphor. Moreover, the surface of the plate coated with the release agent may be flat, or an uneven structure may be formed on the resin sheet as an uneven surface.

INDUSTRIAL APPLICABILITY The light emitting device of the present invention can be suitably used as a light source for illumination, a backlight source for LED displays, liquid crystal display devices, traffic signals, illuminated switches, various sensors, various indicators, and the like.

DESCRIPTION OF SYMBOLS 10... Light emitting element (1... Growth board|substrate, 2... 1st conductivity type (n-type) semiconductor layer, 3... Active layer, 4... 2nd conductivity type (p-type) semiconductor layer, 5... Translucent conductive layer, 6 2nd electrode (p-side pad electrode) 7 1st electrode (n-side pad electrode) 8 protective film) 11 semiconductor element structure 14 protective element 15 adhesive 16 light emission Part 20 (20a to d)... Light transmission member (21... Surface on light emitting side, 22, 24, 25... Reflective surface, 23... Light emitting surface) 26... Resin layer, 28... Adhesive, 30 to 34... Coating member , 35... Light reflective material, 40... Light transmitting (wavelength conversion) member, 50, 58... Mounting substrate/base material (51 to 52... Wiring pattern, 55 to 57... Frame body or laminated substrate or base material), 60 ... conductive adhesive, 61 ... conductor, 71 ... dispenser, 72 ... upper mold

Claims (7)

a light emitting element;
a translucent member having a first surface and a second surface facing each other, the second surface being bonded to the light emitting element;
a covering member that exposes the first surface of the translucent member, covers the side surface of the translucent member and the side surface of the light emitting element, and has light reflectivity ;
A light-transmitting member having a light-incident side surface arranged to face the first surface of the light-transmitting member and the surface of the covering member, wherein the light-incident side surface is included in the surface of the covering member. and
The light-emitting device, wherein the surface of the covering member has an inclined surface that is inclined downward from the first surface. 2. The light emitting device according to claim 1, wherein said light transmitting member is directly bonded to said first surface and said inclined surface. 3. The light-emitting device according to claim 1, further comprising a substrate on which said light-emitting element is mounted. 4. The light-emitting device according to claim 3, further comprising a frame that holds the covering member on the substrate. 5. The light emitting device according to claim 4, wherein said frame is formed integrally with said substrate. 6. The light emitting device according to claim 1, wherein said light transmitting member has a hemispherical surface or a convex curved surface. 7. The light emitting device according to any one of claims 1 to 6, wherein the translucent member includes a wavelength conversion member.

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