WO2013179623A1 - Led module - Google Patents

Abstract

An LED module is provided with a translucent light-diffusing substrate, an LED chip that is joined via a transparent first joining section to one of the surface sides of the light-diffusing substrate, and a color conversion section that covers the LED chip at the one surface side of the light-diffusing substrate. The color conversion section is formed from a transparent material containing a fluorescent substance that is excited by light emitted from the LED chip and that emits light of a different color than that of the LED chip. The LED module comprises a mounting substrate that is arranged on the other surface side of the light-diffusing substrate. The mounting substrate comprises an insulating member having electrical insulating properties, and a wiring pattern that is embedded in the insulating member and electrically connected with the LED chip. The insulating member is made of a non-translucent member having diffuse reflection properties.

Description

LED module

The present invention relates to an LED module.

Conventionally, as a light emitting device that requires white light emission, a light emitting device having a configuration shown in FIG. 27 has been proposed (Japanese Patent Application Publication No. 2007-109701: Patent Document 1). This light-emitting device includes a metal plate 203 having both a heat dissipation function and a light reflection function, a wiring board 201 having a through-hole 207 through which light passes, an adhesive sheet 202 that bonds the wiring board 201 and the metal plate 203, and It has. In this light emitting device, a light emitting element 214 made of an LED chip is mounted on a metal plate 203 just below the through hole 207 of the wiring board 201, and the light emitting element 214 and the land 206 on the upper surface of the wiring board 201 are made of metal. The wire 215 is connected by wire bonding.

In the above-described light emitting device, it is described that an aluminum plate or the like is used as the metal plate 203.

27, it is assumed that a part of the light emitted from the light emitting layer of the light emitting element 214 is transmitted through the light emitting element 214 and reflected by the metal plate 203 in the light emitting device having the configuration shown in FIG. However, in this light emitting device, it is estimated that the light extraction efficiency is reduced due to the fact that the light totally reflected by the metal plate 203 is absorbed in the light emitting element 214 or multiple reflected. The

The present invention has been made in view of the above reasons, and an object thereof is to provide an LED module capable of improving the light extraction efficiency.

The LED module of the present invention includes a light-transmitting light diffusing substrate, an LED chip bonded to one surface side of the light diffusing substrate via a transparent first bonding portion, and the one surface side of the light diffusing substrate. And a color conversion unit that covers the LED chip, and a mounting substrate disposed on the other surface side of the light diffusion substrate, and the color conversion unit is excited by light emitted from the LED chip and the LED The mounting substrate is made of a transparent material containing a phosphor that emits light of a color different from that of the chip, and the mounting substrate is electrically connected to the insulating member embedded in the insulating member. And the insulating member is a non-translucent member having diffuse reflectivity.

In this LED module, the LED chip is provided with a first electrode and a second electrode on one surface side in the thickness direction, and each of the first electrode and the second electrode has the wiring pattern and the wire. It is preferable that a part of the wiring pattern is provided in a vertical projection region to the mounting substrate side of the light diffusion substrate.

In this LED module, the light diffusing substrate is embedded in the insulating member, and a side surface and the other surface are in contact with the insulating member. The mounting substrate has the wiring pattern that is the one of the light diffusing substrates. A portion provided on the surface, and the wiring pattern is formed by bonding the other end portion of each of the wires, each of which is bonded to the first electrode and the second electrode, and the portion, The color conversion unit preferably covers the LED chip and the wires on the one surface side of the light diffusion substrate.

In the LED module of the present invention, it is possible to improve the light extraction efficiency by including a light diffusion substrate and a non-translucent member having diffuse reflection properties.

1A is a schematic plan view of the LED module of Embodiment 1. FIG. 1B is a schematic cross-sectional view of the LED module of Embodiment 1. FIG. 2A and 2B are explanatory diagrams of light traveling paths in the structure of Reference Example 1. FIG. 3A to 3D are explanatory diagrams of structural parameters in the structure of Reference Example 1. FIG. FIG. 4 is a diagram showing a simulation result of the relationship between the absorption rate in the light emitting layer of the LED chip and the light extraction efficiency in the structure of Reference Example 1. FIG. 5 is a diagram showing the relationship between the absorption rate in the light emitting layer of the LED chip and the light extraction efficiency ratio in the structure of Reference Example 1. 6 is a diagram showing a simulation result of the breakdown of the light extraction efficiency in the structure of Reference Example 1. FIG. FIG. 7 is an explanatory diagram of the measurement results of the light fluxes of Reference Examples 2, 3 and 4. FIG. 8 is an explanatory diagram of the measurement results of the light fluxes of Reference Examples 2, 3 and 4. FIG. 9 is an explanatory diagram of the measurement results of the light fluxes of Reference Examples 2, 3 and 4. FIG. 10 is an explanatory diagram of the relationship between the total reflectance and the wavelength. FIG. 11A is a schematic plan view of the LED module of Embodiment 2. FIG. FIG. 11B is a schematic cross-sectional view of the LED module of Embodiment 2. FIG. 12A is a schematic plan view of the LED module of Embodiment 3. FIG. FIG. 12B is a schematic cross-sectional view of the LED module of Embodiment 3. FIG. 13 is a schematic perspective view of a light diffusion substrate in the LED module of the third embodiment. FIG. 14 is an explanatory diagram of the relationship between the particle diameter of the alumina particles and the reflectance. FIG. 15 is a reflectance-wavelength characteristic diagram of a light diffusion substrate and an alumina substrate in an example of the LED module of Embodiment 3. FIG. 16 is a schematic explanatory view of a light diffusion substrate in the LED module of Embodiment 3. FIG. 17 is an explanatory diagram of the relationship between the glass mixture ratio of the light diffusion substrate and the integrated intensity of the integrating sphere in the LED module of Embodiment 1. FIG. 18 is a reflectance-wavelength characteristic diagram of the light diffusion substrate and the alumina substrate in the example of the third embodiment. FIG. 19 is an estimation mechanism diagram for explaining the principle relating to the improvement of the light extraction efficiency of the LED module of the third embodiment. 20A to 20C are estimation mechanism diagrams for explaining the principle relating to the improvement of the light extraction efficiency of the LED module of Embodiment 3. FIG. FIG. 21 is a schematic cross-sectional view of a first modification of the LED module of Embodiment 3. FIG. 22 is a schematic perspective view of a second modification of the LED module of the third embodiment. FIG. 23A is a schematic perspective view in which the lighting fixture of Embodiment 3 is partially broken. FIG. 23B is an enlarged view of a main part of FIG. 23A. FIG. 24A is a schematic perspective view in which the straight tube LED lamp of Embodiment 3 is partially broken. FIG. 24B is an enlarged view of a main part of FIG. 24A. FIG. 25 is a schematic perspective view of a first modification of the lighting fixture according to the third embodiment. FIG. 26 is a partially broken schematic perspective view of a first modification of the lighting apparatus of Embodiment 3. FIG. 27 is a cross-sectional view showing a conventional light emitting device.

(Embodiment 1)
Below, the LED module 1 of this embodiment is demonstrated based on FIG. 1A and 1B.

The LED module 1 includes a translucent light diffusing substrate 2, an LED chip 4 bonded to the one surface 2 sa side of the light diffusing substrate 2 via a transparent first bonding portion 3, and one surface of the light diffusing substrate 2. And a color conversion unit 5 that covers the LED chip 4 on the 2sa side. The color conversion unit 5 is formed of a transparent material containing a phosphor that is excited by light emitted from the LED chip 4 and emits light of a color different from that of the LED chip 4. In addition, the LED module 1 includes a mounting substrate 7 disposed on the other surface 2sb side of the light diffusion substrate 2. The mounting substrate 7 includes an insulating member 72 having electrical insulation, and a wiring pattern 71 embedded in the insulating member 72 and electrically connected to the LED chip 4. The insulating member 72 has diffuse reflectivity. It consists of a non-light-transmissive member.

Accordingly, the LED module 1 emits light from the light emitting layer 43 (see FIGS. 2A and 2B) of the LED chip 4, and a part of the light that has passed through the LED chip 4 and the first joint portion 3 is within the light diffusion substrate 2. It is diffused or taken out from the side surface 2sc of the light diffusion substrate 2. Therefore, the LED module 1 includes a light transmissive light diffusing substrate 2 and a non-light transmissive member (insulating member 72) that is disposed on the other surface 2sb side of the light diffusing substrate 2 and has diffuse reflectivity. As a result, the light extraction efficiency can be improved.

Hereinafter, each component of the LED module 1 will be described in detail.

The LED chip 4 is provided with a first electrode (not shown) as an anode electrode and a second electrode (not shown) as a cathode electrode on one surface side in the thickness direction of the LED chip 4. .

2A and 2B, the LED chip 4 includes an LED structure section 40 having an n-type semiconductor layer 42, a light emitting layer 43, and a p-type semiconductor layer 44 on the main surface 41a side of the substrate 41. The stacking order of the n-type semiconductor layer 42, the light-emitting layer 43, and the p-type semiconductor layer 44 is the n-type semiconductor layer 42, the light-emitting layer 43, and the p-type semiconductor layer 44 in this order from the side closer to the substrate 41. Alternatively, the p-type semiconductor layer 44, the light emitting layer 43, and the n-type semiconductor layer 42 may be arranged in this order. The LED chip 4 preferably has a structure in which a buffer layer is provided between the LED structure portion 40 and the substrate 41. The light emitting layer 43 preferably has a single quantum well structure or a multiple quantum well structure, but is not limited thereto. For example, in the LED chip 4, the n-type semiconductor layer 42, the light emitting layer 43, and the p-type semiconductor layer 44 may form a double heterostructure. The structure of the LED chip 4 is not particularly limited. As the LED module 1, when an LED chip having a structure that does not include a reflective layer (for example, a reflective part such as a Bragg reflector) is employed as the LED chip 4, an LED chip that includes a reflective layer is employed. Compared with the case where it does, the improvement effect of the light extraction efficiency by having the light-diffusion board | substrate 2 and the insulating member 72 which consists of a non-light-transmissive member which has diffuse reflection property is large.

As the LED chip 4, for example, a GaN blue LED chip that emits blue light can be adopted. In this case, the LED chip 4 includes a sapphire substrate as the substrate 41. However, the substrate 41 of the LED chip 4 is not limited to the sapphire substrate, and may be any substrate that is transparent to the light emitted from the light emitting layer 43, for example.

The chip size of the LED chip 4 is not particularly limited. As the LED chip 4, for example, one having a chip size of 0.3 mm □ (0.3 mm × 0.3 mm), 0.45 mm □ (0.45 mm × 0.45 mm), 1 mm □ (1 mm × 1 mm), etc. Can be used. Further, the planar shape of the LED chip 4 is not limited to a square shape, and may be, for example, a rectangular shape. When the planar shape of the LED chip 4 is rectangular, the LED chip 4 having, for example, a chip size of 0.5 mm × 0.24 mm can be used.

Further, the LED chip 4 does not particularly limit the material and the emission color of the light emitting layer 43. That is, the LED chip 4 is not limited to a blue LED chip, and for example, a violet light LED chip, an ultraviolet light LED chip, a red LED chip, a green LED chip, or the like may be used.

As the material of the first joint portion 3 that joins the LED chip 4 and the light diffusion substrate 2, for example, a silicone resin, an epoxy resin, a hybrid material of a silicone resin and an epoxy resin, or the like can be employed.

As the material of the light diffusion substrate 2, for example, translucent ceramics (alumina, barium sulfate, etc.) can be employed. The translucent ceramics can adjust the transmittance, reflectance, and thermal conductivity depending on the type and concentration of the binder, additive, and the like. In the LED module 1, an LED chip 4 is bonded to a central portion on the one surface 2 sa side of the light diffusion substrate 2 via a transparent first bonding portion 3. As a result, the LED module 1 makes it easier for light emitted from the light emitting layer 43 of the LED chip 4 to the other side in the thickness direction of the LED chip 4 to be extracted from the side surface of the LED chip 4. And is easily taken out from the peripheral portion of one surface 2sa of the light diffusion substrate 2. Therefore, the LED module 1 can improve the light extraction efficiency.

The light diffusion substrate 2 is formed in a rectangular plate shape, but is not limited thereto, and may be, for example, a circular shape or a polygonal shape. The planar size of the light diffusion substrate 2 is set larger than the planar size of the LED chip 4. Thereby, the LED module 1 can improve the light extraction efficiency.

The light diffusion substrate 2 is configured to have a linear expansion coefficient close to that of the LED chip 4, thereby relieving stress acting on the LED chip 4 due to the difference in linear expansion coefficient between the LED chip 4 and the mounting substrate 7. It preferably has a stress relaxation function. Thereby, the LED module 1 can relieve the stress acting on the LED chip 4 due to the difference in linear expansion coefficient between the LED chip 4 and the mounting substrate 7.

Moreover, it is preferable that the light diffusion substrate 2 has a heat conduction function for transferring heat generated by the LED chip 4 to the mounting substrate 7 side. The light diffusing substrate 2 preferably has a heat conduction function for transferring heat generated by the LED chip 4 to a range wider than the chip size of the LED chip 4. Thereby, the LED module 1 can efficiently dissipate the heat generated in the LED chip 4 through the light diffusion substrate 2 and the mounting substrate 7.

The shape of the color conversion unit 5 may be set as appropriate based on the planar shape of the LED chip 4 and the like. For example, when the planar shape of the LED chip 4 is rectangular, the color conversion unit 5 has a semi-elliptical spherical shape, and the major axis direction and the minor axis direction of the color conversion unit 5 in plan view are determined in plan view. It is preferable to align with the longitudinal direction and the lateral direction of the LED chip 4. Moreover, when the planar shape of the LED chip 4 is a square shape, it is preferable that the shape of the color conversion unit 5 be a hemispherical shape. However, the shape of the color conversion unit 5 is not particularly limited, and may be set as appropriate based on desired light distribution characteristics of the LED module 1. The color conversion unit 5 covers not only the LED chip 4 but also a part of each wire 8 connected to the LED chip 4. The color conversion unit 5 is in contact with the one surface side and the side surface of the LED chip 4 and the peripheral portion of the one surface 2sa of the light diffusion substrate 2. The color conversion unit 5 can be formed by a molding method, for example.

シ リ コ ー ン Silicone resin is used as the transparent material that is the material of the color conversion section 5. The transparent material is not limited to a silicone resin, and for example, an epoxy resin, an acrylic resin, glass, an organic / inorganic hybrid material in which an organic component and an inorganic component are mixed and bonded at the nm level or molecular level, and the like can also be employed.

The phosphor that is the material of the color conversion unit 5 functions as a wavelength conversion material that converts light emitted from the LED chip 4 into light having a longer wavelength than the light. Thereby, the LED module 1 can obtain mixed color light of the light emitted from the LED chip 4 and the light emitted from the phosphor.

For example, when the LED module 1 employs a blue LED chip as the LED chip 4 and a yellow phosphor as the phosphor of the wavelength conversion material, white light can be obtained. That is, the LED module 1 can emit the blue light emitted from the LED chip 4 and the light emitted from the yellow phosphor through the surface of the color conversion unit 5 and obtain white light.

The phosphor that is the wavelength conversion material is not limited to the yellow phosphor, and for example, a yellow phosphor and a red phosphor, or a red phosphor and a green phosphor may be employed. Further, the phosphor as the wavelength conversion material is not limited to one type of yellow phosphor, and two types of yellow phosphors having different emission peak wavelengths may be employed. The LED module 1 can improve the color rendering properties by adopting a plurality of kinds of phosphors as the wavelength conversion material.

In the LED module 1 of the present embodiment, the other surface 2sb side of the light diffusion substrate 2 is bonded to the wiring pattern 71 via a transparent second bonding portion (not shown). In short, the light diffusion substrate 2 and the mounting substrate 7 are bonded via the transparent second bonding portion. As the material of the second joint portion, for example, a silicone resin, an epoxy resin, a hybrid material of a silicone resin and an epoxy resin, or the like can be employed.

The mounting substrate 7 includes a non-translucent wiring pattern 71 to which the LED chip 4 is electrically connected, and an insulating member 72 in which the wiring pattern 71 is embedded and having electrical insulation. The wiring pattern 71 is a conductor pattern for supplying power to the LED chip 4. The conductor pattern means a patterned conductor portion.

In the mounting substrate 7, the insulating member 72 covers most of the main surface side of the wiring pattern 71 as well as the back surface side of the wiring pattern 71. On the main surface side of the wiring pattern 71, the mounting substrate 7 has a hole 73 through which the other end portion of each wire 8 having one end portion bonded to each of the first electrode and the second electrode of the LED chip 4 is passed to the insulating member 72. Is formed.

As the material of the wiring pattern 71, for example, aluminum, aluminum alloy, silver, copper, phosphor bronze, copper alloy (for example, 42 alloy), nickel alloy, or the like can be used. The wiring pattern 71 can be formed using, for example, a lead frame, a metal foil, a metal film, or the like. The lead frame is a metal frame and is formed from a strip-shaped metal hoop material. The thickness of the metal hoop material is preferably set in the range of about 100 μm to 1500 μm, for example.

The lead frame may be appropriately provided with a surface treatment layer (not shown) having a higher reflectance with respect to light from the LED chip 4 than the metal hoop material on the main surface side. As the surface treatment layer, for example, an Ag film, a laminated film of Ni film, Pd film and Au film, a laminated film of Ni film and Au film, a laminated film of Ag film, Pd film and AuAg alloy film are adopted. can do. The surface treatment layer is a laminate of a Ni film, a Pd film, and an Au film rather than an Ag film from the viewpoint of long-term reliability (for example, oxidation resistance, corrosion resistance, adhesion to the insulating member 72, etc.). A film, a laminated film of an Ni film and an Au film, an Ag film, a Pd film, and an AuAg alloy film are more preferable. The surface treatment layer is preferably composed of a plating layer or the like. In short, the surface treatment layer is preferably formed by a plating method. The lead frame is not limited to the main surface side, and a surface treatment layer may be formed on the whole. Further, the surface treatment layer on the main surface side of the lead frame may be partially formed by spot plating or the like.

As the metal hoop material, an aluminum film having a purity higher than that of the aluminum plate is laminated on one surface side of the aluminum plate as a base material, and the dielectric film is composed of two kinds of dielectric films having different refractive indexes. It is also possible to use a highly reflective substrate on which an increased reflection film is laminated. Here, as the two types of dielectric films, for example, an SiO ₂ film and a TiO ₂ film are preferably employed. As the highly reflective substrate, for example, MIRO2 and MIRO (registered trademark) manufactured by alanod can be used. As the above-mentioned aluminum plate, an anodized surface may be used. When the above-described highly reflective substrate is used as the metal hoop material, it is necessary to form a conductive film for electrical connection with each wire 8 by a plating method or to pattern the reflective film. .

The wiring pattern 71 includes a first conductor portion (first pattern) 71a in which one of the first electrode and the second electrode of the LED chip 4 is electrically connected via the wire 8, a first electrode, A second conductor portion (second pattern) 71b electrically connected to the other of the second electrodes via the wire 8. In the example of FIG. 1, the first electrode is electrically connected to the first conductor portion 71 a via the wire 8, and the second electrode is electrically connected to the second conductor portion 71 b via the wire 8. Yes.

In the mounting substrate 7, it is preferable that a surface treatment layer whose outermost layer is an Au film is formed on the main surface side of a region other than the region covered with the insulating member 72 in the wiring pattern 71. The material of the surface treatment layer is preferably a material having higher oxidation resistance and corrosion resistance than the material of the wiring pattern 71. Here, the surface treatment layer is, for example, a laminated film of a Ni film, a Pd film, and an Au film when the wiring pattern 71 is formed using the above-described lead frame and the material of the wiring pattern 71 is Cu. It is preferably made of a laminated film of a Ni film and an Au film. As a result, the surface treatment layer has high oxidation resistance and corrosion resistance, and it is possible to increase the bonding strength with the gold wire constituting the wire 8, and the surface of the wiring pattern 71 is made of Cu. It becomes possible to suppress the diffusion into the Au film of the treatment layer.

The planar shape of the mounting substrate 7 is a rectangular shape. On the other hand, in the wiring pattern 71, the first conductor portion 71a and the second conductor portion 71b are arranged in parallel in the specified direction (the left-right direction in FIG. 1A), and the first conductor portion 71a and the second conductor portion 71b The virtual quadrangle including both of them is slightly smaller than the outer peripheral shape of the insulating member 72 and is formed to be a rectangle similar to the outer peripheral shape. Here, the outer dimensions of the wiring pattern 71 are set so that the first conductor portion 71a and the second conductor portion 71b occupy most of the virtual quadrangle. Specifically, the first conductor portion 71a has a rectangular outer peripheral shape, and the length dimension in the prescribed direction is greater than three-quarters of the side length along the prescribed direction of the virtual quadrangle. It is set to a slightly smaller dimension, and the length dimension in the direction perpendicular to the prescribed direction is set to the same dimension as the side length along the direction perpendicular to the prescribed direction of the virtual quadrangle. The length of the second conductor portion 71b in the specified direction is set to be slightly smaller than a quarter of the length of the side along the specified direction of the virtual quadrangle. The length dimension in the orthogonal direction is set to the same dimension as the length of the side along the direction orthogonal to the prescribed direction of the virtual quadrangle. The mounting substrate 7 does not particularly limit the shape and size of each of the first conductor portion 71a and the second conductor portion 71b, but it is preferable that the plane area of the wiring pattern 71 is close to the plane area of the insulating member 72. Thereby, the LED module 1 can improve heat dissipation. In the wiring pattern 71, the sizes of the first conductor portion 71a and the second conductor portion 71b may be reversed. In addition, the wiring pattern 71 includes the first conductor portion 71a so that the light diffusion substrate 2 is accommodated in one of the projection regions of the first conductor portion 71a and the second conductor portion 71b in the thickness direction of the wiring pattern 71. It is preferable that the outer dimensions of the second conductor portion 71b are set.

It is preferable that a part of the wiring pattern 71 is provided in the vertical projection region of the light diffusing substrate 2 on the mounting substrate 7 side of the mounting substrate 7. Thereby, the LED module 1 can spread the heat generated in the LED chip 4 in the thickness direction and the lateral direction (in-plane direction) of the wiring pattern 71 and transfer the heat to the back surface side of the insulating member 72. Therefore, the LED module 1 can improve heat dissipation and suppress an increase in temperature of the LED chip 4, and can further increase the light output. From the viewpoint of improving heat dissipation, the mounting substrate 7 is provided with a part of the first conductor portion 71a of the wiring pattern 71 over the entire vertical projection region of the light diffusion substrate 2 on the mounting substrate 7 side. It is more preferable that it is provided over the entire area of the defined area larger than the vertical projection area.

The planar shape of the mounting substrate 7 is not limited to a rectangular shape, and may be, for example, a circular shape, an elliptical shape, a triangular shape, or a polygonal shape other than a rectangular shape.

The insulating member 72 is a non-translucent member having diffuse reflectivity. The insulating member 72 is formed of a material obtained by adding a filler for increasing the reflectance to a resin. As an example, the insulating member 72 can employ unsaturated polyester as a resin and titania as a filler. The resin of the insulating member 72 is not limited to unsaturated polyester, and for example, vinyl ester can be used. Moreover, as a filler, not only titania but magnesium oxide, boron nitride, aluminum hydroxide etc. can be used, for example.

The insulating member 72 has a hole 73 that exposes one location of each of the first conductor portion 71 a and the second conductor portion 71 b in the vicinity of the light diffusion substrate 2, and the first conductor portion 71 a in the outer peripheral portion of the mounting substrate 7. The second conductor portion 71b is patterned to have an opening (not shown) that exposes one location. As a result, the first conductor portion 71a and the second conductor portion 71b have portions exposed in the vicinity of the light diffusion substrate 2 constituting a connecting portion to which the wire 8 is connected, and portions exposed at the outer peripheral portion of the mounting substrate 7. Constitutes a terminal portion for external connection.

The hole 73 has a circular opening shape. The inner diameter of the hole 73 is set to 0.5 mm, but this value is an example and is not particularly limited. The shape of the hole 73 is not limited to a circular shape, and may be, for example, a rectangular shape or an elliptical shape. One hole 73 is formed on each side of the LED chip 4 in plan view.

As an example of a method for forming the mounting substrate 7, for example, first, a lead frame having the wiring pattern 71 is prepared, and then a surface treatment layer is formed on the wiring pattern 71 by an electrolytic plating method. Thus, the insulating member 72 in which the wiring pattern 71 is embedded may be formed, and then unnecessary portions of the lead frame may be cut. The method for forming the mounting substrate 7 is an example. The forming method of the mounting substrate may be another forming method.

The number of LED chips 4 arranged on the one surface 7sa side of the mounting substrate 7 is not limited to one and may be plural. When the number of LED chips 4 is plural, the number of LED chips 4 and the number of light diffusion substrates 2 may be the same, or the number of light diffusion substrates 2 may be smaller than the number of LED chips 4. . In short, the LED module 1 may have, for example, a configuration in which one LED chip 4 is bonded to one light diffusion substrate 2 via the first bonding portion 3 by the number of LED chips 4. A structure in which each of the plurality of LED chips 4 is bonded to one light diffusion substrate 2 via the first bonding portion 3 may be used.

The LED module 1 may have a configuration in which, for example, the planar shape of the mounting substrate 7 is long, and a plurality of LED chips 4 are arranged along the longitudinal direction of the mounting substrate 7. In this case, the wiring pattern 71 may be configured such that a plurality of LED chips 4 can be connected in series, connected in parallel, or configured to be connected in series-parallel.

The wire 8 is not limited to a gold wire, and for example, an aluminum wire can be employed.

The LED module 1 can efficiently diffuse and reflect the light emitted from the LED chip 4 and the light emitted from the phosphor on the surface of the insulating member 72. Therefore, the LED module 1 has a configuration in which the planar size of the mounting substrate 7 is larger than the planar size of the light diffusion substrate 2, but the light emitted from the LED chip 4 and the light emitted from the phosphor are the insulating member 72. It is possible to prevent the LED module 1 from being diffusely reflected and absorbed by the mounting substrate 7, thereby improving the light extraction efficiency. Further, since the LED module 1 includes the light diffusing substrate 2, the insulating member 72 directly below the light diffusing substrate 2 does not come into contact with air, so that the insulating member 72 is less likely to deteriorate over time, and the influence due to deterioration over time is reduced. It becomes possible to do.

The LED module 1 according to the present embodiment diffuses and reflects a light transmissive light diffusing substrate 2, light emitted from the LED chip 4 and light emitted from the phosphor disposed on the other surface 2 sb side of the light diffusing substrate 2. By providing a non-translucent member (insulating member 72) having diffuse reflection property, it is possible to improve the light extraction efficiency and to increase the light output (light flux). It becomes.

The LED module 1 preferably includes a color converter 5 and a cover (not shown) made of a transparent material that covers each wire 8 exposed from the color converter 5 on the one surface 7sa side of the mounting substrate 7. As the material of the cover portion, the same material as the transparent material that is the material of the color conversion portion 5 can be used. That is, as the cover material, for example, silicone resin, epoxy resin, epoxy resin, acrylic resin, glass, organic / inorganic hybrid materials in which organic and inorganic components are mixed and combined at the nm level or molecular level are used. can do. In addition, it is preferable that the light emission surface of the cover part has a shape along the light emission surface of the color conversion unit 5. In addition, when the LED module 1 is manufactured, after forming the color conversion unit 5, for example, by using a dispenser or the like, the holes 73 are filled with the material of the cover unit so that the wires 8 do not contact the light diffusion substrate 2. Then, what is necessary is just to form a cover part.

Incidentally, in order to solve the problem of improving the light extraction efficiency, the inventors of the present application particularly attach the LED chip 4 to the submount member 20 (see FIGS. 2A, 2B, 3A to 3D, 7 to 9), Focusing on the support member 170 (see FIGS. 7 to 9) disposed on the side opposite to the LED chip 4 side in the submount member 20, intensive research was conducted.

First, the inventors of the present application relate to a structure (Reference Example 1) in which the LED chip 4 is mounted on the submount member 20 by bonding the LED chip 4 to the submount member 20 via the first joint portion 3. The difference in the light extraction efficiency due to the difference in the material of the member 20 was examined. As the LED chip 4, a GaN-based blue LED chip was prepared in which the substrate 41 was a sapphire substrate and the light emitted from the light emitting layer 43 was blue light. Further, as the submount member 20, a translucent ceramic substrate (translucent alumina substrate) and a metal plate (Ag substrate, Al substrate) having a higher reflectance than the translucent ceramic substrate were prepared. Moreover, the material of the 1st junction part 3 was made into the silicone resin.

FIG. 2A schematically shows the travel path of light emitted from an arbitrary point of the light emitting layer 43 with an arrow when the submount member 20 is a translucent ceramic substrate in the structure of Reference Example 1. . FIG. 2B schematically shows the travel path of light emitted from an arbitrary point of the light emitting layer 43 with an arrow when the submount member 20 is an Ag substrate in the structure of Reference Example 1. The light extraction efficiency in the structure of Reference Example 1 was 8 to 10% higher when the submount member 20 was a translucent ceramic substrate than when the submount member 20 was an Ag substrate. .

For the structure of Reference Example 1, the structure parameters shown in FIGS. 3A to 3D were set. For the LED chip 4, the planar shape was rectangular, the long side length dimension H41 was 0.5 mm, and the short side length dimension H42 was 0.24 mm. For the LED chip 4, the combined thickness 41 of the substrate 41 and the LED structure 40 is 0.14 mm, the thickness t5 of the LED structure 40 is 0.0004 mm, and the light emitting layer 43 is formed from the one surface of the LED chip 4. The thickness dimension t6 was set to 0.0003 mm. For the LED chip 4, the material of the substrate 41 is sapphire having a refractive index of 1.77, and the LED structure 40 is GaN having a refractive index of 2.5.

In addition, regarding the light emitting layer 43, it is assumed that light of isotropically uniform intensity is radiated from all points of the light emitting layer 43 in all directions.

For the first joint portion 3, the thickness dimension t3 was 0.005 mm, and the material was a silicone resin having a refractive index of 1.41.

For the submount member 20, the planar shape was rectangular, and the lengths H1 and H2 of two adjacent sides were set to 3.75 mm and 3.75 mm, respectively. Therefore, the distance L1 between the LED chip 4 and the outer peripheral line of the submount member 20 in the direction along the longitudinal direction of the LED chip 4 is 1.625 mm, and the LED chip 4 in the direction along the short side direction of the LED chip 4 is used. And the distance L2 between the outer peripheral line of the submount member 20 was 1.755 mm.

Also, regarding the optical characteristics of the submount member 20, in the case of a translucent ceramic substrate, it was assumed that the reflectance was 92% and the transmittance was 8%. Then, in the case where the submount member 20 is a translucent ceramic substrate, the inventors of the present application mix spherical particles having a refractive index different from that of the base material into the base material made of ceramics as shown in FIG. 3D. The refractive index of the base material is 1.77, the refractive index of the particle is 1.0, the particle size is 3.0 μm, and the particle size is calculated so that the values of the reflectance and transmittance described above can be obtained. The concentration was assumed to be 16.5%.

Also, it was assumed that the total luminous flux radiated from the structure of Reference Example 1 was detected by a far field receiver that the structure of Reference Example 1 considered to be at infinity.

Regarding the actual measurement value of the light extraction efficiency, the light extraction efficiency in the structure of Reference Example 1 is 72.5% when the submount member 20 is a translucent ceramic substrate. The light extraction efficiency when the mount member 20 is an Al substrate was 68.7%.

FIG. 4 shows the result of simulating the relationship between the absorption rate in the light emitting layer 43 and the overall light extraction efficiency in the structure of Reference Example 1. D1 in FIG. 4 indicates a simulation result when the submount member 20 is a translucent ceramic substrate. D2 in FIG. 4 shows a simulation result when the submount member 20 is an Al substrate. In this simulation, it is assumed that only the Fresnel loss occurs on the side surface of the LED chip 4. Further, this simulation is a geometric optical simulation based on a ray tracing method using the Monte Carlo method.

From the simulation results shown in FIG. 4, when the light absorption rate in the light emitting layer 43 is about 0.2%, the light extraction efficiency is about 70% for both D1 and D2, and a value close to the actual measurement value is obtained.

FIG. 5 defines the ratio of the light extraction efficiency of the translucent ceramic substrate to the light extraction efficiency when the submount member 20 is an Al substrate in the structure of Reference Example 1 as the light extraction efficiency ratio. The relationship between the light absorption rate of the light emitting layer 43 and light extraction efficiency ratio is shown.

FIG. 5 shows that the light extraction efficiency ratio is larger than 1 regardless of the light absorption rate of the light emitting layer 43. That is, from FIG. 5, if the light absorption rate of the light emitting layer 43 is the same, the submount member 20 is made of a translucent ceramic substrate compared to the case where the submount member 20 is made of an Al substrate in the structure of Reference Example 1. It can be seen that the light extraction efficiency is higher in the case of. In the structure of Reference Example 1, the light extraction efficiency is higher when the submount member 20 is a translucent ceramic substrate than when the submount member 20 is an Al substrate. It is the same.

FIG. 6 shows the result of simulating the breakdown of the light extraction efficiency when the submount member 20 is made of a translucent ceramic substrate and an Al substrate in the structure of Reference Example 1. In FIG. 6, the case where the substrate material is ceramic corresponds to the case where the submount member 20 is a translucent ceramic substrate, and the case where the substrate material is aluminum corresponds to the case where the submount member 20 is an Al substrate. . Regarding the breakdown of the light extraction efficiency, I 1 in FIG. 6 is the light extraction efficiency from the one surface of the LED chip 4. Further, I2 in FIG. 6 is the light extraction efficiency from the side surface of the LED chip 4. Further, I3 in FIG. 6 is the light extraction efficiency from the exposed surface (upper surface) of the submount member 20 on the LED chip 4 side. Moreover, I4 in FIG. 6 is the light extraction efficiency from the side surface of the submount member 20 and the exposed surface (lower surface) opposite to the LED chip 4 side.

From FIG. 6, when the submount member 20 is an Al substrate in the structure of Reference Example 1, I3 and I4 are 0, whereas when the submount member 20 is a translucent ceramic substrate. Although I1 and I2 are slightly reduced, it is understood that the light extraction efficiency of 9.3% is obtained by combining I3 and I4, and the total light extraction efficiency is improved.

7 and 8 show the planar size of the submount member 20 for each of the structure of Reference Example 2 shown at the lower left of each, the structure of Reference Example 3 shown at the lower center of each, and the structure of Reference Example 4 shown at the lower right of each. It is the figure which put together the result of having measured the light beam with the integrating sphere about the case where the thickness is changed variously while the thickness is constant at 2 mm □ (2 mm × 2 mm). The structure of Reference Example 2 is a structure in which a support member 170 disposed on the side opposite to the LED chip 4 side in the submount member 20 is added to the structure of Reference Example 1. The structure of Reference Example 3 is a structure in which a sealing portion 150 made of a silicone resin that seals the LED chip 4 is added to the structure of Reference Example 2. The structure of Reference Example 4 is a structure in which a color conversion unit 5 that covers the LED chip 4 is added to the structure of Reference Example 2. The color conversion unit 5 employs a silicone resin as a transparent material and a yellow phosphor as a wavelength conversion material. The difference between FIG. 7 and FIG. 8 is only that the support member 170 in FIG. 7 is an Al substrate, whereas the support member 170 in FIG. 8 is an Ag substrate. The reflectances of the Al substrate and the Ag substrate are about 78% and about 98%, respectively.

Further, E1, E2, E3, and E4 in FIG. 7 are light flux ratios when the thickness dimensions of the submount member 20 are 0.4 mm, 0.6 mm, 0.8 mm, and 1.0 mm, respectively. Further, F1, F2, F3, and F4 in FIG. 8 are light flux ratios when the thickness dimension of the submount member 20 is 0.4 mm, 0.6 mm, 0.8 mm, and 1.0 mm, respectively. The luminous flux ratio is the same as that of the structure of Reference Example 2, the structure of Reference Example 3 and the structure of Reference Example 4, and a high-purity alumina substrate having a thickness dimension of 1.0 mm is used as the submount member 20 and the support member 170 is eliminated. Relative value of the luminous flux in the reference structure. Therefore, the results of FIGS. 7 and 8 mean that the luminous flux ratio is larger than 1, meaning that the luminous flux is larger than that of the reference structure, and if the luminous flux ratio is smaller than 1, it means that the luminous flux is smaller than that of the reference structure. is doing.

From the result of FIG. 7, when the support member 170 is an Al substrate in the structure of Reference Example 4, the inventors of the present invention can emit a light beam more than the reference structure if the thickness dimension of the submount member 20 is 0.8 mm or more. I thought it was possible to make it bigger. Further, from the results of FIG. 8, when the support member 170 is an Ag substrate in the structure of Reference Example 4, if the thickness dimension of the submount member 20 is 0.8 mm or more, the inventors of the present invention have a structure that is higher than that of the reference structure. We thought that it was possible to increase the luminous flux. Conversely, when the support member 170 is a metal plate such as an Al substrate or an Ag substrate in the structure of Reference Example 4, the inventors of the present invention have the thickness of the submount member 20 from the viewpoint of improving the light extraction efficiency. We thought that thinning of dimensions would be limited.

Further, the inventors of the present application use a white diffuse reflection substrate as the support member 170 in order to reduce the light returning to the LED chip 4 by diffusely reflecting the light reaching the support member 170 from the LED chip 4. It was investigated.

FIG. 9 shows a case where the planar size of the submount member 20 is constant at 2 mm □ and the thickness dimension is 0.4 mm for each of the structure of Reference Example 2, the structure of Reference Example 3, and the structure of Reference Example 4. It is the figure which put together the result of having measured the light beam with the integrating sphere.

E1 in FIG. 9 is a luminous flux ratio when the support member 170 is an Al substrate. F1 in FIG. 9 is a luminous flux ratio when the support member 170 is an Ag substrate. G1 in FIG. 9 is a luminous flux ratio when the support member 170 is a white-type diffuse reflection substrate (a substrate coated with white paint). The reflectance of the diffuse reflection substrate is about 92%. FIG. 10 shows the wavelength dependence of the total reflectance of each of the Ag substrate, MIRO2, and the ceramic substrate (the above-described high-purity alumina substrate) that were compared and examined by the inventors of the present application.

The light beam ratio in FIG. 9 is obtained by using a light beam of each of the structure of Reference Example 2, the structure of Reference Example 3, and the structure of Reference Example 4 and a high-purity alumina substrate having a thickness dimension of 1.0 mm as the submount member 20. This is a relative value with respect to the luminous flux in the reference structure without 170. Therefore, the result of FIG. 9 means that when the luminous flux ratio is larger than 1, it means that the luminous flux is larger than that of the reference structure, and when the luminous flux ratio is smaller than 1, it means that the luminous flux is smaller than that of the reference structure. Yes.

From the results shown in FIG. 9, the inventors of the present invention employ a diffuse reflection substrate as the support member 170, so that the light extraction efficiency is higher than when a metal substrate such as an Al substrate or an Ag substrate is employed as the support member 170. We obtained knowledge that it would be possible to improve.

The inventors of the present application have come to recall the LED module 1 of the present embodiment based on this knowledge.

As described above, the LED module 1 includes the light-transmitting light diffusion substrate 2, the LED chip 4 bonded to the one surface 2sa side of the light diffusion substrate 2 via the transparent first bonding portion 3, and the light diffusion. And a color conversion unit 5 that covers the LED chip 4 on the one surface 2sa side of the substrate 2. Here, the color conversion unit 5 is formed of a transparent material containing a phosphor that is excited by light emitted from the LED chip 4 and emits light of a color different from that of the LED chip 4. In addition, the LED module 1 includes a mounting substrate 7 provided with an insulating member 72 disposed on the other surface 2sb side of the light diffusion substrate 2. The insulating member 72 is made of a non-translucent member having diffuse reflectivity that diffusely reflects light emitted from the LED chip 4 and light emitted from the phosphor. The LED module 1 includes a translucent light diffusing substrate 2 and an insulating member 72 that is disposed on the other surface 2sb side of the light diffusing substrate 2 and constitutes a non-translucent member having diffuse reflectivity. As a result, the light extraction efficiency can be improved, and the light output (light flux) can be increased. The LED module 1 can improve the light extraction efficiency by the light guiding effect of the light diffusion substrate 2, and is emitted from the LED chip 4 to the other surface from the one surface 2sa side of the light diffusion substrate 2. It is assumed that the light that is transmitted to the 2sb side is diffusely reflected by the insulating member 72, thereby improving the conversion efficiency of the phosphor of the color conversion unit 5 and improving the light extraction efficiency.

The wiring pattern 71 of the mounting substrate 7 may be extended to the position of the outer peripheral line in a plan view of the insulating member 72, but the member (for example, the fixture body of the lighting fixture) on which the LED module 1 is mounted is formed of a conductive material. In such a case, it is preferable that the desired creepage distance with the member can be ensured only by extending the position to the inner side of the outer peripheral line.

Moreover, since the back surface side of the wiring pattern 71 in the mounting substrate 7 is covered with the insulating member 72, the LED module 1 is made of a metal member (for example, a metal fixture body or a heat dissipation member in a lighting fixture). When installed and used, lightning surge resistance can be improved.

(Embodiment 2)
Below, the LED module 1 of this embodiment is demonstrated based on FIG.

The LED module 1 according to the present embodiment is different from the LED module according to the first embodiment in that the light diffusing substrate 2 is embedded in the insulating member 72 and the side surface 2sc and the other surface 2sb of the light diffusing substrate 2 are in contact with the insulating member 72. Different from module 1. In addition, about the component similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

Further, the mounting substrate 7 includes a portion where the wiring pattern 71 is provided on one surface 2sa of the light diffusion substrate 2. Here, the wiring pattern 71 includes a portion where the first conductor portion 71 a and the second conductor portion 71 b are provided on the one surface 2 sa of the light diffusion substrate 2. A first extending portion 71ab, which is a combination of a portion formed along the thickness direction of the mounting substrate 7 in the first conductor portion 71a and a portion provided on the one surface 2sa of the light diffusion substrate 2, is represented by L It has a letter shape. Further, a second extending portion 71bb, which is a combination of the portion formed along the thickness direction of the mounting substrate 7 in the second conductor portion 71b and the portion provided on the one surface 2sa of the light diffusion substrate 2, is represented by L It has a letter shape.

In the wiring pattern 71, the other end portion of the wire 8 whose one end portion is bonded to the first electrode and the portion provided on the one surface 2sa of the light diffusion substrate 2 in the first conductor portion 71a are bonded. . In addition, the wiring pattern 71 has the other end of the wire 8 whose one end is bonded to the second electrode and the portion provided on the one surface 2sa of the light diffusion substrate 2 in the second conductor 71b. ing. That is, in the wiring pattern 71, the other end of the wire 8 is joined to the tip of each of the first extending part 71ab and the second extending part 71bb. The wiring pattern 71 is formed using one lead frame. Here, the first extension part 71ab and the second extension part 71bb are, for example, rectangular regions that become the first extension part 71ab and the second extension part 71bb, respectively, in the metal hoop material that is the source of the lead frame. The U-shaped slits along the three sides can be formed by pressing the metal hoop material, and then the rectangular region can be bent. The wiring pattern 71 is not limited to being formed using a lead frame, and may be formed using a metal film, a metal foil, or the like. When the wiring pattern 71 is formed using a metal film or a metal foil, it is possible to form the wiring pattern 71 including the entire projection area of the light diffusion substrate 2 in the thickness direction of the light diffusion substrate 2. .

The color conversion unit 5 covers the LED chip 4 and each wire 8 on the one surface 2sa side of the light diffusion substrate 2.

In the LED module 1 of this embodiment, the light diffusion substrate 2 is embedded in the insulating member 72, the side surface 2sc and the other surface 2sb of the light diffusion substrate 2 are in contact with the insulating member 72, and the color conversion unit 5 Since the LED chip 4 and each wire 8 are covered on the one surface 2sa side of the diffusion substrate 2, the reliability can be improved without forming a cover portion like the LED module 1 of the first embodiment. . Thereby, the LED module 1 of this embodiment can achieve cost reduction compared with the LED module 1 of Embodiment 1.

(Embodiment 3)
Below, the LED module 1 of this embodiment is demonstrated based on FIG.

The LED module 1 of the present embodiment is different from the LED module 1 of the first embodiment in that the light diffusion substrate 2 is composed of two ceramic layers 2a and 2b that overlap in the thickness direction. In addition, about the component similar to the LED module 1 of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

In the light diffusion substrate 2, the optical characteristics of the ceramic layers 2a and 2b are different from each other, and the ceramic layer 2a far from the LED chip 4 has a higher reflectance with respect to the light emitted from the LED chip 4. Here, the optical characteristics include reflectance, transmittance, absorption rate, and the like. The light diffusing substrate 2 is composed of a plurality of ceramic layers that overlap in the thickness direction, and the optical characteristics of the ceramic layers are different from each other, and the ceramic layer farther from the LED chip 4 has a higher reflectivity with respect to light emitted from the LED chip 4. As long as it has.

Accordingly, in the LED module 1, light emitted from the light emitting layer 43 (see FIG. 2A) of the LED chip 4 to the other surface side in the thickness direction of the LED chip 4 is diffused at the interface between the ceramic layer 2b and the ceramic layer 2a. It becomes easy to be reflected. Thereby, the LED module 1 can suppress the light emitted from the LED chip 4 to the light diffusion substrate 2 side from returning to the LED chip 4 and can be incident on the one surface 7sa of the mounting substrate 7. It becomes possible to suppress light, and it becomes easy to extract light from the one surface 2sa and the side surface 2sc of the light diffusion substrate 2. Therefore, the LED module 1 can improve the light extraction efficiency, and can reduce the influence of the reflectance of the mounting substrate 7 on the light extraction efficiency, thereby suppressing the temporal change of the light extraction efficiency. It becomes possible to do.

For the light diffusion substrate 2, for convenience of explanation, the uppermost ceramic layer 2b closest to the LED chip 4 is referred to as a first ceramic layer 2b, and the lowermost ceramic layer 2a farthest from the LED chip 4 is referred to as a second ceramic layer 2a. Sometimes called.

As the material of the first ceramic layer 2b, for example, alumina (Al ₂ O ₃ ) can be employed. Here, the 1st ceramic layer 2b can be comprised with an alumina substrate, for example. When the first ceramic layer 2b is composed of an alumina substrate, the particle diameter of the alumina particles is preferably 1 μm to 30 μm. The first ceramic layer 2b can reduce the reflectance when the particle diameter of the alumina particles is large, and can increase the scattering effect when the particle diameter of the alumina particles is small. In short, reducing the reflectivity and increasing the scattering effect are in a trade-off relationship.

The above-mentioned particle size is a value obtained from a number-based particle size distribution curve. The number-based particle size distribution curve is obtained by measuring the particle size distribution by an image imaging method. Specifically, the SEM image is obtained by observing with a scanning electron microscope (SEM), and the SEM image is obtained. Is obtained from the size (biaxial average diameter) and number of particles obtained by image processing. In this number-based particle size distribution curve, the particle size value when the integrated value is 50% is called the median diameter (d ₅₀ ), and the above-mentioned particle size means the median diameter.

Theoretically, the relationship between the particle size of the spherical alumina particles on the alumina substrate and the reflectance is as shown in FIG. 14, and the reflectance increases as the particle size decreases. The relationship between the median diameter (d ₅₀ ) of the first ceramic layer 2b and the measured value of the reflectance was substantially the same as the theoretical value of FIG. The measured value of reflectance is a value measured using a spectrophotometer and an integrating sphere.

As a material of the second ceramic layer 2a, for example, SiO ₂ , Al ₂ O ₃ and Al ₂ O ₃ having a higher refractive index (for example, ZrO ₂ , TiO _2, etc.), CaO and BaO are included as components. Composite materials can be employed. The second ceramic layer 2a preferably has an Al ₂ O ₃ particle diameter of 0.1 μm to 1 μm. The second ceramic layer 2a can adjust optical characteristics (reflectance, transmittance, absorptivity, etc.) by adjusting the composition, composition, particle size, thickness, and the like of the composite material. When the light diffusion substrate 2 employs the same material for the first ceramic layer 2b and the second ceramic layer 2a, the particle size of the first ceramic layer 2b may be larger than the particle size of the second ceramic layer 2a.

In the embodiment of the LED module 1, the thickness Hs of the light diffusion substrate 2 is 0.5 mm, the thickness Hsa of the second ceramic layer 2a is 0.1 mm, and the reflectance of the second ceramic layer 2a with respect to light having a wavelength of 450 nm is set. 96%, the thickness Hsb of the first ceramic layer 2b is 0.4 mm, and the reflectance of the first ceramic layer 2b with respect to light having a wavelength of 450 nm is 80%. However, these numerical values are only examples and are particularly limited. is not. In the embodiment of the LED module 1, the planar size of the light diffusion substrate 2 is 2 mm □ (2 mm × 2 mm), but it is not particularly limited.

The reflectance-wavelength characteristics of the light diffusion substrate 2 used in the example of the LED module 1 are as indicated by A1 in FIG. Further, the reflectance-wavelength characteristic of the single layer alumina substrate having a thickness of 0.4 mm was as indicated by A2 in FIG. The reflectance-wavelength characteristics in FIG. 15 are the results of measurement using a spectrophotometer and an integrating sphere.

The first ceramic layer 2b is a first dense layer made of ceramics fired at a high temperature of about 1500 ° C. to 1600 ° C. In the first ceramic layer 2b, ceramic particles are firmly bonded by high-temperature firing, and the first ceramic layer 2b has better rigidity than the second ceramic layer 2a. Here, good rigidity means that the bending strength is relatively high. As a material of the first ceramic layer 2b, alumina is preferable.

Further, the second ceramic layer 2a is a ceramic fired at 1000 ° C. or less (for example, 850 ° C. to 1000 ° C.), which is a relatively low temperature compared to the first ceramic layer 2b. The ceramic constituting the second ceramic layer 2a is, for example, a second dense layer containing a ceramic filler (ceramic fine particles) and a glass component, or a porous layer containing a ceramic filler (ceramic fine particles) and a glass component. It can be.

The second dense layer is a ceramic in which the ceramic fillers are bonded together by sintering, and the glass component is arranged around the ceramic filler as a matrix. In the second dense layer, the ceramic filler mainly exhibits a light reflecting function. For the second dense layer, for example, a material in which a ceramic filler is mixed with glass ceramics containing borosilicate glass, zinc borosilicate glass and alumina, glass ceramics containing soda lime glass and alumina, or the like can be used. The glass content contained in the glass ceramic is preferably set in the range of about 35 to 60 wt%. The content of the ceramic contained in the glass ceramic is preferably set in the range of about 40 to 60 wt%. Note that the second dense layer can also increase the refractive index of the glass ceramic by replacing the zinc component of the borosilicate glass with titanium oxide or tantalum oxide. The material of the ceramic filler is preferably a material having a higher refractive index than glass ceramics, for example, tantalum pentoxide, niobium pentoxide, titanium oxide, barium oxide, barium sulfate, magnesium oxide, calcium oxide, strontium oxide, zinc oxide, Zirconium oxide, silicate oxide (zircon), or the like can be used.

When the second ceramic layer 2a is composed of a porous layer (hereinafter, the "second ceramic layer 2a" in this case is also referred to as "porous layer 2a"), as shown in the schematic diagram of FIG. The first glass layer 20aa is interposed between the porous layer 2a having a large number of pores 20c and the first ceramic layer 2b, and the second glass layer 20ab on the opposite side of the porous layer 2a from the first ceramic layer 2b side. Are preferably laminated. The porosity of the porous layer 2a is set to about 40%, but is not particularly limited. Each of the first glass layer 20aa and the second glass layer 20ab is a transparent layer made of a glass component and transmits visible light. The thicknesses of the first glass layer 20aa and the second glass layer 20ab may be set to, for example, about 10 μm, but are not particularly limited. About half of each glass component of the first glass layer 20aa and the second glass layer 20ab is composed of SiO ₂ , but is not particularly limited.

The first glass layer 20aa is disposed so as to be interposed between the porous layer 2a and the first ceramic layer 2b, and is in close contact with the surface of the porous layer 2a and the surface of the first ceramic layer 2b by firing during manufacturing. ing.

The second glass layer 20ab is disposed on the opposite side of the porous layer 2a from the first ceramic layer 2b side, and protects the porous layer 2a. Thereby, the pores 20c existing on the surface of the porous layer 2a opposite to the first ceramic layer 2b side are sealed by the second glass layer 20ab.

The porous layer 2a includes a ceramic filler (ceramic fine particles) and a glass component. In the porous layer 2a, ceramic fillers are bonded by sintering to form a cluster, and a porous structure is formed. The glass component serves as a binder for the ceramic filler. In the porous layer 2a, the ceramic filler and the numerous pores 20c exhibit the main light reflecting function. The porous layer 2a can be formed, for example, according to the package manufacturing process disclosed in paragraphs [0023]-[0026] and [FIG. 4] of International Publication No. WO2012 / 039442 A1.

The porous layer 2a can change the reflectance by changing the weight ratio of the glass component and the ceramic component (alumina, zirconia, etc.), for example. That is, the reflectance of the porous layer 2a can be changed by changing the glass blending ratio. In FIG. 17, the horizontal axis represents the glass mixture ratio, and the vertical axis represents the integrated intensity by the integrating sphere for the reflected light when light is incident on the porous layer 2 a. In the integrating sphere, reflected light having a wavelength of 380 to 780 nm was integrated. From FIG. 17, it can be seen that the reflectance can be increased by lowering the glass blending ratio.

In the example of the LED module 1 of the present embodiment, the first ceramic layer 2b is formed by firing alumina at 1600 ° C., and the porous layer 2a is formed by a weight ratio of 20:80 between the glass component and the ceramic component. It forms by baking the material mix | blended so that it may become at 850 degreeC. In the examples, borosilicate glass having a median diameter of about 3 μm is used as the glass component, and alumina having a median diameter of about 0.5 μm and a median diameter of about 2 μm is used. As zirconia, a median diameter of about 0.2 μm is used. In the embodiment, the thickness of the first ceramic layer 2b is 0.38 mm, and the thickness of the porous layer 2a is 0.10 mm. The reflectance-wavelength characteristics of the light diffusion substrate 2 in the example were as indicated by A3 in FIG. Further, the reflectance-wavelength characteristic of a single layer alumina substrate having a thickness of 0.38 mm was as indicated by A4 in FIG. The weight ratio between the glass component and the ceramic component in the porous layer 2a and the particle size (median diameter) of each material are not particularly limited.

The porous layer 2a has a gradient composition in which the concentration of the glass component gradually decreases from both sides in the thickness direction to the inside when the glass components of the first glass layer 20aa and the second glass layer 20ab penetrate during manufacturing. have.

Specifically, as a result of observing a cross section along the thickness direction of the porous layer 2a having a thickness of about 100 μm with a microscope, in each region having a depth of about 20 μm from both sides in the thickness direction of the porous layer 2a, the unit Glass occupies an area of 70% or more per area, and there is a dense layer of glass. On the other hand, in the inner region where the depth from both sides in the thickness direction of the porous layer 2a is deeper than 20 μm, the glass occupies an area of about 20% per unit area, and the glass and the ceramic filler are in a certain ratio to each other. There are sparse mixed layers.

In the LED module 1 of the present embodiment, the light diffusion substrate 2 is composed of two ceramic layers 2 a and 2 b having different optical characteristics, and the ceramic layer 2 a farther from the LED chip 4 is closer to the LED chip 4. Compared with 2b, the reflectance with respect to the light radiated | emitted from LED chip 4 is high. Thereby, the LED module 1 of this embodiment can improve light extraction efficiency compared with the case where the light-diffusion board | substrate 2 is comprised only by the single layer alumina substrate. In the LED module 1 of the present embodiment, it is possible to reduce the light reflected by the one surface 2sa of the light diffusion substrate 2 and to reduce the absorption loss in the LED chip 4. Furthermore, in the LED module 1 of this embodiment, the light absorption rate (approximately 0%) in the light diffusion substrate 2 is made lower than the light absorption rate (for example, about 2 to 8%) in the mounting substrate 7. A part of the light incident on one surface 2sa of the light diffusion substrate 2 is scattered in the first ceramic layer 2b or reflected at the interface between the first ceramic layer 2b and the second ceramic layer 2a. It becomes possible to do. Therefore, the LED module 1 can reduce the light that passes through the light diffusion substrate 2 and reaches the one surface 7sa of the mounting substrate 7, and can reduce the absorption loss in the mounting substrate 7. The light extraction efficiency can be improved.

By the way, in the LED module 1 of the present embodiment, the first ceramic layer 2b and the second ceramic layer 2a relatively increase the light transmittance of the first ceramic layer 2b, and the second ceramic layer 2a The light scattering rate is increased. Thereby, the LED module 1 can diffuse light by the second ceramic layer 2a far from the LED chip 4, and is diffused before reaching the mounting substrate 7 as compared with the case of only the first ceramic layer 2b. It is assumed that there will be more light. Further, in the LED module 1, it is assumed that the light reflected by the mounting substrate 7 immediately below the light diffusion substrate 2 is likely to be diffused without returning to the LED chip 4. Further, in the LED module 1, when the light diffusion substrate 2 is configured only by the second ceramic layer 2a, the light emitted from the LED chip 4 toward the light diffusion substrate 2 is highly likely to be scattered near the LED chip 4. Therefore, it is estimated that the possibility that the light scattered near the LED chip 4 returns to the LED chip 4 is increased. Therefore, it is conceivable that the LED module 1 can reduce the light returning to the LED chip 4 as compared with the case where the light diffusion substrate 2 is configured only by the second ceramic layer 2a. Further, in the LED module 1, the thickness of the light diffusing substrate 2 required to obtain the same reflectance as the light diffusing substrate 2 is reduced as compared with the case where the light diffusing substrate 2 is configured by only the first ceramic layer 2b. It becomes possible.

The color converter 5 is formed in a hemispherical shape covering the LED chip 4 and a part of each wire 8 on the one surface 2sa of the light diffusion substrate 2. For this reason, in LED module 1, it is preferable to provide the sealing part (not shown) which covers each remaining part of each wire 8, and the color conversion part 5. FIG. The sealing portion is preferably made of a transparent material. As the transparent material of the sealing portion, for example, an organic / inorganic hybrid material in which an organic component and an inorganic component are mixed and bonded at the nm level or the molecular level, such as silicone resin, epoxy resin, acrylic resin, glass, or the like may be employed. it can. The transparent material of the sealing part is preferably a material having a small difference in linear expansion coefficient from the transparent material of the color conversion part 5, and more preferably a material having the same linear expansion coefficient. Thereby, in the LED module 1, stress concentrates on each of the wires 8 near the interface between the sealing portion and the color conversion portion 5 due to the difference in linear expansion coefficient between the sealing portion and the color conversion portion 5. Can be suppressed. Therefore, the LED module 1 can suppress the disconnection of each wire 8. Furthermore, the LED module 1 can suppress the occurrence of cracks in the sealing part or the color conversion part 5 due to the difference in linear expansion coefficient between the sealing part and the color conversion part 5. Moreover, although it is preferable to form a sealing part, for example in a hemispherical shape, it is not restricted to this, For example, it is good also as shapes, such as a semi-elliptical spherical shape and a semi-cylindrical shape.

The principle of improving the light extraction efficiency of the LED module 1 will be described with reference to the estimation mechanism diagrams of FIGS. 19, 20A, 20B, and 20C. Note that the LED module 1 of the present embodiment is within the scope of the present invention even if the estimation mechanism is different.

19, 20 </ b> A, 20 </ b> B, and 20 </ b> C schematically show the travel path of light emitted from the light emitting layer 43 (see FIG. 2A) of the LED chip 4. 19, 20 </ b> A, and 20 </ b> B schematically show the traveling path of the light emitted from the light emitting layer 43 and reflected by the one surface 2sa of the light diffusion substrate 2. 19, 20 </ b> A, 20 </ b> B, and 20 </ b> C each schematically shows a traveling path of light emitted from the light emitting layer 43 and entering the light diffusion substrate 2.

As shown in FIGS. 19, 20A and 20B, the inventors of the present application, in the first ceramic layer 2b, due to the difference in refractive index between the ceramic particles and the grain boundary phase (glass component is the main component), It was estimated that reflection and refraction occurred at the interface with the grain boundary phase. Further, as shown in FIGS. 19 and 20C, the inventors of the present application caused a difference in the refractive index between ceramic particles and pores or grain boundary phases (mainly glass components) in the second ceramic layer 2a. It was estimated that reflection and refraction occurred at the interface between the particle and the pore or grain boundary phase. Further, as shown in FIGS. 19 and 20C, the inventors of the present application reflected on the interface between the pores and the grain boundary phase due to the difference in refractive index between the pores and the grain boundary phase in the second ceramic layer 2a. It was estimated that refraction occurred. In addition, regarding the ceramic plate material, the inventors of the present invention, if the plate thickness is the same, the larger the particle size of the ceramic particles, the fewer the number of interfaces, and the case where the ceramic particles and Since the probability of passing through the interface with the grain boundary phase is reduced, it is estimated that the reflectance is reduced and the transmittance is increased.

The inventors of the present application can improve the light extraction efficiency of the LED module 1 by transmitting the light emitted from the LED chip 4 as much as possible in the first ceramic layer 2b and reflecting it as much as possible in the second ceramic layer 2a. I guessed it. For this reason, in the light diffusion substrate 2, it is preferable that the first ceramic layer 2b and the second ceramic layer 2a have a relatively large particle size of the ceramic particles in the first ceramic layer 2b. It is preferable that the ceramic particles have a relatively small particle size and the second ceramic layer 2a includes pores.

In the LED module 1 of the present embodiment, the light diffusion substrate 2 is composed of the two ceramic layers 2a and 2b that are overlapped in the thickness direction, whereby the light extraction efficiency can be improved.

In the LED module 1 of the present embodiment, a plurality of ceramic layers (first ceramic layer 2b and second ceramic layer 2a) in the light diffusion substrate 2 constitute light-transmitting layers having different optical characteristics.

In short, the light diffusion substrate 2 includes a plurality of light-transmitting layers that overlap in the thickness direction, and the optical characteristics of the light-transmitting layers are different from each other, and the light-transmitting layers that are farther from the LED chip 4 are radiated from the LED chip 4. What is necessary is just to have a property with the high reflectance with respect to light. Hereinafter, the uppermost light transmitting layer closest to the LED chip 4 may be referred to as a first light transmitting layer, and the lowermost light transmitting layer farthest from the LED chip 4 may be referred to as a second light transmitting layer.

The first light transmissive layer is preferably made of a material having a high transmittance of light emitted from the LED chip 4 and a refractive index close to the refractive index of the LED chip 4. That the refractive index of the first light transmissive layer is close to the refractive index of the LED chip 4 is that the difference between the refractive index of the first light transmissive layer and the refractive index of the substrate 41 (see FIGS. 2A and 2B) in the LED chip 4 is. It means 0.1 or less, and the difference in refractive index is more preferably 0. The first light transmissive layer is preferably made of a material having high heat resistance.

The material of the first light transmissive layer is not limited to ceramic, and for example, glass, SiC, GaN, GaP, sapphire, epoxy resin, silicone resin, unsaturated polyester, and the like can be employed. The ceramic material is not limited to Al ₂ O ₃ , but may be other metal oxides (eg, magnesia, zirconia, titania), metal nitride (eg, aluminum nitride). The material of the first light transmissive layer is preferably ceramic rather than single crystal from the viewpoint of forward scattering the light emitted from the LED chip 4.

As the translucent ceramic, for example, Lumicera (registered trademark), which is a product of Murata Manufacturing Co., Ltd., Hi-Serum (product name) of NGK Co., Ltd., and the like can be employed. Lumisera (registered trademark) has a Ba (Mg, Ta) O ₃ -based composite perovskite structure as a main crystal phase. High serum is a translucent alumina ceramic.

When the material of the first light transmitting layer is ceramic, the particle size is preferably about 1 μm to 5 μm.

The first light-transmitting layer may be formed by forming a void or a modified portion with a changed refractive index inside the single crystal. The voids and modified portions can be formed, for example, by condensing and irradiating laser light from a femtosecond laser to the formation regions of the voids and modified portions in the single crystal. The wavelength of the laser light of the femtosecond laser, the irradiation conditions, and the like may be appropriately changed depending on the material of the single crystal, the object to be formed (gap, modified portion), the size of the object to be formed, and the like. The first light-transmitting layer is made of a base resin (for example, epoxy resin, silicone resin, unsaturated polyester, etc.) with a filler having a refractive index different from that of the base resin (hereinafter referred to as “first base resin”). Hereinafter, it may be referred to as “first filler”). The first filler preferably has a smaller refractive index difference from the first base resin. The first filler preferably has a higher thermal conductivity. In addition, the first light transmissive layer preferably has a higher filling density of the first filler from the viewpoint of increasing the thermal conductivity. The shape of the first filler is preferably spherical from the viewpoint of suppressing total reflection of incident light. The first filler has less reflection and refraction as the particle size is larger. The first light-transmitting layer has a first filler having a relatively large particle size on the side close to the LED chip 4 in the thickness direction of the first light-transmitting layer, and particles relatively on the side far from the LED chip 4. You may comprise so that there may be a 1st filler with a small diameter. In this case, the first light transmissive layer may be formed by multilayering a plurality of layers having different particle sizes of the first filler.

Of the surface on the LED chip 4 side (one surface 2sa of the light diffusing substrate 2) in the first light transmissive layer, the light diffusing substrate is radiated from the LED chip 4 to the light diffusing substrate 2 around the LED chip 4 mounting region. It is preferable that a fine concavo-convex structure portion for suppressing the total reflection of the light reflected or refracted inside 2 is formed. The concavo-convex structure portion may be formed by roughening the surface of the first light-transmitting layer by, for example, sandblasting. As for the surface roughness of the concavo-convex structure portion, for example, the arithmetic average roughness Ra defined by JIS B 0601-2001 (ISO 4287-1997) is preferably about 0.05 μm.

The light diffusing substrate 2 is a substrate in which a resin layer having a refractive index smaller than that of the first light-transmitting layer is formed around the LED chip 4 mounting area on the surface of the first light-transmitting layer on the LED chip 4 side. It may be adopted. As a material for the resin layer, for example, a silicone resin, an epoxy resin, or the like can be employed. As a material for the resin layer, a resin containing a phosphor may be used.

The second light transmissive layer is preferably configured to diffusely reflect the light radiated from the LED chip 4 rather than the light transmissive layer.

The material of the second light transmissive layer is not limited to ceramic, and for example, glass, SiC, GaN, GaP, sapphire, epoxy resin, silicone resin, unsaturated polyester, and the like can be employed. The ceramic material is not limited to Al ₂ O ₃ , but may be other metal oxides (eg, magnesia, zirconia, titania), metal nitride (eg, aluminum nitride).

In the case of ceramic, the material of the second light transmissive layer preferably has a particle size of 1 μm or less, more preferably about 0.1 μm to 0.3 μm. Further, the second light transmissive layer can be constituted by, for example, the porous layer 2a described above. When the first light-transmitting layer was constituted by the first ceramic layer 2b made of alumina having a purity of 99.5%, the bulk density was 3.8 to 3.95 g / cm ³ . The first light-transmitting layer had a bulk density of 3.7 to 3.8 g / cm ³ when constituted by the first ceramic layer 2b made of alumina having a purity of 96%. On the other hand, when the second light-transmitting layer was composed of the porous layer 2a, the bulk density was 3.7 to 3.8 g / cm ³ . The above-described bulk density is a value estimated by observing with an SEM, obtaining an SEM image, and performing image processing on the SEM image.

The second light transmissive layer may be formed by forming a void, a modified portion in which the refractive index is changed, or the like inside the single crystal. The voids and modified portions can be formed, for example, by condensing and irradiating laser light from a femtosecond laser to the formation regions of the voids and modified portions in the single crystal. The wavelength of the laser beam of the femtosecond laser, the irradiation conditions, and the like may be changed as appropriate depending on the material of the single crystal, the formation target (gap, modified portion), the size of the formation target, and the like. The second light transmissive layer is made of a base resin (for example, epoxy resin, silicone resin, unsaturated polyester, fluororesin, etc.) and has a refractive index different from that of the base resin (hereinafter referred to as “second base resin”). A different filler (hereinafter referred to as “second filler”) may be included. The second light-transmitting layer has a second filler having a relatively large particle size on the side close to the LED chip 4 in the thickness direction of the second light-transmitting layer, and the particle on the side far from the LED chip 4 is relatively small. You may comprise so that there may be a 2nd filler with a small diameter. The material of the second filler, for example, white inorganic materials are preferred, for example, can be employed metal oxides such as TiO ₂ or ZnO. The particle size of the second filler is preferably about 0.1 μm to 0.3 μm, for example. The filling rate of the second filler is preferably about 50 to 75 wt%, for example. Further, as the silicone resin of the second base resin, for example, methyl silicone or phenyl silicone can be employed. In the case of solid particles, the second filler preferably has a larger refractive index difference from the second base resin. As a material containing the second filler in the second base resin, for example, KER-3200-T1 manufactured by Shin-Etsu Chemical Co., Ltd. can be used.

Also, as the second filler, core-shell particles or hollow particles can be employed. For the core-shell particles, the refractive index of the core can be arbitrarily set, but is preferably smaller than the refractive index of the second base resin. The hollow particles are preferably gas (for example, air, inert gas) or a vacuum inside and have a refractive index smaller than that of the second base resin.

Further, the second light transmissive layer may be composed of a light diffusion sheet. As the light diffusion sheet, for example, a white polyethylene terephthalate sheet containing a large number of bubbles can be employed.

When both the first light-transmitting layer and the second light-transmitting layer are ceramic, the light diffusing substrate 2 is formed by superposing and sintering ceramic green sheets for forming each of them. be able to. In the light diffusion substrate 2, when the second light-transmitting layer includes bubbles, the first light-transmitting layer may also include bubbles, but the first light-transmitting layer is more than the second light-transmitting layer. It is preferable that the number of bubbles is small and the bulk density is large.

The first light-transmitting layer and the second light-transmitting layer are preferably made of a material having high resistance to light and heat from the LED chip 4 and the phosphor.

The LED module 1 may include a reflective layer that reflects light from the LED chip 4 or the like on the other surface 2 sb side of the light diffusion substrate 2. As a material for the reflective layer, silver, aluminum, a silver-aluminum alloy, other silver alloys, aluminum alloys, or the like can be employed. The reflective layer can be composed of, for example, a thin film, metal foil, solder resist (solder), or the like. The reflective layer may be provided on the light diffusion substrate 2 or may be provided on the mounting substrate 7.

The LED module 1 may have a shape in which the color conversion unit 5 covers the LED chip 4, the wires 8, and the light diffusion substrate 2 as in the first modification shown in FIG. 21. Thereby, the LED module 1 can suppress the disconnection of each wire 8, and can improve the reliability.

The shape of the color conversion unit 5 is hemispherical, but is not limited thereto, and may be, for example, a semi-elliptical spherical shape or a semi-cylindrical shape.

Below, the 2nd modification of the LED module 1 of this embodiment is demonstrated based on FIG.

In the LED module 1 of the second modified example, the mounting substrate 7 has a long shape, and includes a plurality of LED chips 4 (see FIG. 21). In addition, about the component similar to the LED module 1 of a 1st modification, the same code | symbol is attached | subjected and description is abbreviate | omitted.

In the LED module 1, a plurality of LED chips 4 are arranged in a specified direction on the one surface 7 sa side of the mounting substrate 7. In the LED module 1, the LED chips 4 arranged in the specified direction and the wires 8 (see FIG. 21) connected to the LED chips 4 are covered with a line-shaped color conversion unit 5. . The color conversion unit 5 is preferably provided with a recess 5b that suppresses total reflection of light emitted from the adjacent LED chips 4 between the adjacent LED chips 4 in the prescribed direction.

The first conductor portion 71a and the second conductor portion 71b are provided one by one for a group of LED chips 4 arranged in the specified direction.

The planar shape of each of the first conductor portion 71a and the second conductor portion 71b is formed in a comb shape. The first conductor portion 71 a and the second conductor portion 71 b are arranged so as to be intertwined with each other in the direction along the short direction of the mounting substrate 7. Here, in the wiring pattern 71, the first comb portion 71a1 of the first conductor portion 71a and the second comb portion 71b1 of the second conductor portion 71b are opposed to each other. In the wiring pattern 71, the first comb teeth 71a2 of the first conductor portion 71a and the second comb teeth 71b2 of the second conductor portion 71b are alternately arranged in the direction along the longitudinal direction of the mounting substrate 7 with a gap. Are lined up.

The LED module 1 has a plurality of (for example, nine) LED chips 4 arranged in the longitudinal direction of the mounting substrate 7 (the prescribed direction) connected in parallel. The LED module 1 can supply power to a parallel circuit in which the plurality of LED chips 4 are connected in parallel. In short, the LED module 1 can supply power to all the LED chips 4 by supplying power between the first conductor portion 71a and the second conductor portion 71b. When a plurality of LED modules 1 are used side by side, adjacent LED modules 1 are connected to each other by, for example, a conductive member, an electric wire for feed wiring (not shown), a connector (not shown), or the like. May be electrically connected. In this case, it is possible to supply power from a single power supply unit to the plurality of LED modules 1 to cause all LED chips 4 of each LED module 1 to emit light.

As described above, the color conversion unit 5 is provided with the recess 5b that suppresses total reflection of light emitted from the adjacent LED chips 4 between the adjacent LED chips 4 in the prescribed direction. preferable. Thereby, the LED module 1 can suppress total reflection of light emitted from the LED chip 4 and incident on the boundary surface between the color conversion unit 5 and air. Therefore, since the LED module 1 can reduce the light confined due to the total reflection as compared with the case where the color conversion unit 5 has a semi-cylindrical shape, the light extraction efficiency can be improved. In short, the LED module 1 can reduce the total reflection loss, and can improve the light extraction efficiency.

The color converter 5 is formed in a cross-sectional shape reflecting a step between the one surface of each LED chip 4 and the one surface 7sa of the mounting substrate 7. Therefore, in the color conversion unit 5, the cross-sectional shape orthogonal to the arrangement direction of the LED chips 4 is convex, and the cross-sectional shape along the arrangement direction of the LED chips 4 is uneven. In short, in the LED module 1, a concavo-convex structure for improving the light extraction efficiency is formed in the line-shaped color conversion unit 5.

The period of this uneven structure is the same as the arrangement pitch of the LED chips 4. The period of the concavo-convex structure is the arrangement pitch of the convex portions 5a covering each of the LED chips 4.

The shape of the surface of the color conversion unit 5 is designed so that the angle formed by the normal of the point where the light rays from the LED chip 4 intersect on the surface of the color conversion unit 5 and the light ray is smaller than the critical angle. preferable. Here, the LED module 1 is arranged so that the incident angle (light incident angle) of the light beam from the LED chip 4 is smaller than the critical angle over substantially the entire surface of each convex portion 5a of the color conversion unit 5. It is preferable to design the shape of the surface of the converter 5.

For this reason, in the color conversion part 5, it is preferable that each convex part 5a covering each LED chip 4 is formed in a hemispherical shape. Each of the convex portions 5 a is designed such that the optical axis of the convex portion 5 a overlapping in the thickness direction of the light diffusion substrate 2 coincides with the optical axis of the LED chip 4. Thereby, the LED module 1 can not only suppress total reflection on the surface of the color conversion unit 5 (the boundary surface between the color conversion unit 5 and air) but also suppress color unevenness. It becomes possible. Color unevenness is a state in which chromaticity changes depending on the light irradiation direction. The LED module 1 can suppress color unevenness to such an extent that it cannot be visually recognized.

The LED module 1 can make the optical path length from the LED chip 4 to the surface of the convex portion 5a substantially uniform regardless of the light emission direction from the LED chip 4, and can further suppress color unevenness. Become. Each convex part 5a of the color conversion part 5 is not limited to a hemispherical shape, and may be, for example, a semi-elliptical spherical shape. Each of the convex portions 5a may have a semi-cylindrical shape or a rectangular parallelepiped shape.

In manufacturing the LED module 1, first, the mounting substrate 7 is prepared. Thereafter, the light diffusion substrate 2 associated with each LED chip 4 is bonded onto the mounting substrate 7. Thereafter, each LED chip 4 is die-bonded to the one surface 2sa side of the corresponding light diffusion substrate 2 by a die-bonding apparatus or the like. Thereafter, the first electrode and the second electrode of each LED chip 4 are connected to the wiring pattern 71 via the wire 8 by a wire bonding apparatus or the like. Thereafter, the color conversion unit 5 is formed using a dispenser system or the like.

When the color conversion unit 5 is formed by the dispenser system, for example, the material of the color conversion unit 5 is discharged from the nozzle and applied while moving the dispenser head along the arrangement direction of the LED chips 4.

Here, when applying the material of the color conversion unit 5 by the dispenser system so as to have an application shape based on the surface shape of the color conversion unit 5, for example, the material may be applied by discharging the material while moving the dispenser head. That's fine. As an example, by changing the moving speed of the dispenser head, the application amount is changed, and by moving the dispenser head up and down, the distance between the nozzle and one surface 7sa of the mounting substrate 7 immediately below the nozzle is changed. Yes. More specifically, when the material is applied to the base of each convex portion 5a of the color conversion unit 5 and the material is applied to the base of the portion between the adjacent convex portions 5a of the color conversion unit 5 In this case, the movement speed is relatively different. In the former case, the movement speed is reduced, and in the latter case, the movement speed is increased. Further, the dispenser head is moved up and down based on the surface shape of the color converter 5. By these, in the method of forming the color conversion part 5 with a dispenser system, it becomes possible to make the material into a coating shape based on the surface shape of the color conversion part 5. The application shape may be set in consideration of shrinkage when the material is cured.

The dispenser system includes a moving mechanism including a robot that moves the dispenser head, a sensor unit that measures the height of each surface 7sa of the mounting substrate 7 and the nozzle from the table, and the amount of material discharged from the moving mechanism and the nozzle. And a controller for controlling. The controller can be realized, for example, by mounting an appropriate program on a microcomputer. In addition, the dispenser system corresponds to a plurality of different types of products such as the arrangement pitch of the LED chips 4, the number of LED chips 4, and the line width of the color conversion unit 5 by appropriately changing the program installed in the controller. It becomes possible.

Also, the surface shape of the color conversion unit 5 can be controlled, for example, by adjusting the viscosity of the material. The curvature of each surface (convex curved surface) of each convex portion 5a can be designed by the viscosity and surface tension of the material, the height of the wire 8, and the like. Increasing the curvature can be realized by increasing the viscosity of the material, increasing the surface tension, or increasing the height of the wire 8. Further, it is possible to reduce the width (line width) of the line-shaped color conversion unit 5 by increasing the viscosity of the material or increasing the surface tension. The viscosity of the material is preferably set in the range of about 100 to 2000 mPa · s. As the viscosity value, for example, a value measured at room temperature using a conical plate type rotational viscometer can be adopted.

The dispenser system may also include a heater that heats the uncured material to a desired viscosity. Thereby, the dispenser system can improve the reproducibility of the application shape of the material, and can improve the reproducibility of the surface shape of the color conversion unit 5.

By the way, the LED module 1 can be used as a light source of various illumination devices. As an example of the illuminating device provided with the LED module 1, for example, an illuminating device in which the LED module 1 is used as a light source and a lamp (for example, a straight tube LED lamp, a light bulb-shaped lamp, etc.) arranged in the apparatus main body can be cited. However, other lighting devices may be used. Here, the LED module 1 includes a desired creepage distance between the wiring pattern 71 and the instrument main body by including the insulating member 72 even when the instrument main body is made of metal and has conductivity. Can be secured. In the lighting fixture, if the fixture body is made of metal, the heat generated in the LED module 1 can be radiated more efficiently.

The material of the instrument body is preferably a material having a high thermal conductivity, and more preferably a material having a higher thermal conductivity than the insulating member 72. Here, it is preferable to employ a metal having a high thermal conductivity such as aluminum or copper as the material of the instrument body.

As a means for attaching the LED module 1 to the appliance main body, for example, an attachment such as a screw may be employed, or an epoxy resin layer of a thermosetting sheet adhesive is provided between the appliance main body and the LED module 1. It may be interposed between and joined. B-stage epoxy resin layer (thermosetting resin) and plastic containing fillers such as silica and alumina as the sheet-like adhesive and having a property of lowering viscosity and increasing fluidity upon heating A sheet adhesive in which a film (PET film) is laminated can be used. An example of such a sheet-like adhesive is an adhesive sheet TSA manufactured by Toray Industries, Inc. As the filler, an electrically insulating material having higher thermal conductivity than the epoxy resin that is a thermosetting resin may be used. The thickness of the epoxy resin layer described above is set to 100 μm, but this value is merely an example, and is not particularly limited. For example, the thickness may be appropriately set in the range of about 50 μm to 150 μm. The thermal conductivity of the epoxy resin layer is preferably 4 W / m · K or more.

The epoxy resin layer of the above-mentioned sheet-like adhesive has properties of being electrically insulating and having high thermal conductivity, high fluidity during heating, and high adhesion to the uneven surface. Therefore, the lighting fixture can prevent the generation of a gap between the insulating layer formed from the above-described epoxy resin layer, the LED module 1 and the fixture body, and can improve the adhesion reliability. In addition, it is possible to suppress the increase in thermal resistance and the occurrence of variations due to insufficient adhesion. The insulating layer has electrical insulation and thermal conductivity, and has a function of thermally coupling the LED module 1 and the instrument body.

Thus, the lighting fixture has a rubber sheet shape such as Sarcon (registered trademark) or a silicone gel-like heat dissipation sheet (heat conductive sheet) between the LED module 1 and the fixture body, respectively. It becomes possible to reduce the thermal resistance from the LED chip 4 to the appliance body, and to reduce the variation in thermal resistance. As a result, the lighting fixture has improved heat dissipation and can suppress the temperature rise of the junction temperature of each LED chip 4, so that the input power can be increased and the light output can be increased. It becomes possible to plan. The thickness of the epoxy resin layer described above is set to 100 μm, but this value is merely an example, and is not particularly limited. For example, the thickness may be appropriately set in the range of about 50 μm to 150 μm. Note that the thermal conductivity of the epoxy resin layer is preferably 4 W / m · K or more.

For straight tube LED lamps, for example, the Japan Light Bulb Industry Association has standardized “Straight tube LED lamp system with L-type pin cap GX16t-5 (for general lighting)” (JEL 801: 2010). Has been.

When configuring such a straight tube type LED lamp, for example, a straight tubular tube body formed of a translucent material (for example, milky white glass, milky white resin, etc.) and a longitudinal direction of the tube body. A first base and a second base are provided at one end and the other end, respectively, and the mounting substrate 7 is elongated in the tube body, and a plurality of LED chips 4 are arranged in the longitudinal direction of the mounting substrate 7. What is necessary is just to set it as the structure which accommodated the LED module 1 arranged.

Below, the lighting fixture 50 provided with the LED module 1 of the 2nd modification as a light source is demonstrated based on FIG. 23A and 23B.

The lighting fixture 50 is an LED lighting fixture, and includes a fixture main body 51 and an LED module 1 that is a light source held by the fixture main body 51.

The appliance body 51 is formed in a long shape (here, a rectangular plate shape) having a larger planar size than the LED module 1. As for the lighting fixture 50, the LED module 1 is arrange | positioned at the one surface 51b side of the thickness direction of the fixture main body 51. As shown in FIG. In the lighting fixture 50, the LED module 1 is arranged with respect to the fixture body 51 so that the longitudinal direction of the LED module 1 and the longitudinal direction of the fixture body 51 are aligned. In the lighting fixture 50, a cover 52 that covers the LED module 1 is disposed on the one surface 51 b side of the fixture body 51. The cover 52 has a function of transmitting light emitted from the LED module 1.

Moreover, the lighting fixture 50 includes a lighting device 53 that supplies DC power to the LED module 1 to light (emit) each LED chip 4 (see FIG. 21). In the lighting fixture 50, the lighting device 53 and the LED module 1 are electrically connected via an electric wire 54 such as a lead wire.

The luminaire 50 has a recess 51 a that houses the lighting device 53 on the other surface 51 c side in the thickness direction of the fixture body 51. The recess 51 a is formed along the longitudinal direction of the instrument body 51. In addition, a through hole (not shown) through which the electric wire 54 is inserted is formed in the instrument body 51 through a thin portion between the one surface 51b and the inner bottom surface of the recess 51a.

The LED module 1 can connect the electric wire 54 at the exposed part of the wiring pattern 71. As the connection portion between the wiring pattern 71 and the electric wire 54, for example, a connection portion made of a conductive bonding material such as solder, a connection portion made of a male connector and a female connector, or the like can be adopted.

The luminaire 50 can turn on the LED module 1 by supplying DC power from the lighting device 53 to the LED module 1. Note that the lighting device 53 may have a configuration in which power is supplied from an AC power source such as a commercial power source, or may have a configuration in which power is supplied from a DC power source such as a solar battery or a storage battery.

The light source of the luminaire 50 is not limited to the LED module 1 of the second modified example, and is mounted in the LED module 1 of any one of the first to third embodiments and the first modified example of the third embodiment in the same manner as the second modified example. A configuration in which the substrate 7 has a long shape and includes a plurality of LED chips 4 with respect to one mounting substrate 7 may be used.

The material of the instrument body 51 is preferably a material having a high thermal conductivity, and more preferably a material having a higher thermal conductivity than the mounting substrate 7. Here, as a material of the instrument main body 51, it is preferable to employ a metal having high thermal conductivity such as aluminum or copper. The lighting fixture 50 can improve heat dissipation by making the material of the fixture main body 51 a metal.

As a means for attaching the LED module 1 to the appliance main body 51, for example, an attachment such as a screw may be employed, or an epoxy resin layer of a thermosetting sheet adhesive is used as the appliance main body 51, the LED module 1, and the like. They may be joined by interposing them.

As the material of the cover 52, for example, acrylic resin, polycarbonate resin, silicone resin, glass or the like can be employed.

It is preferable that the cover 52 is integrally provided with a lens portion (not shown) that controls the light distribution of the light emitted from the LED module 1. Thereby, the lighting fixture 50 can achieve cost reduction as compared with a configuration in which a lens separate from the cover 52 is attached to the cover 52.

In the luminaire 50 described above, since the above-described LED module 1 is provided as a light source, the light extraction efficiency can be improved, and the cost can be reduced and the light output can be increased. Become.

Hereinafter, a straight tube LED lamp 60 including the LED module 1 of the second modification as a light source will be described with reference to FIGS. 24A and 24B.

The straight tube LED lamp 60 includes a straight tube (cylindrical) tube body 61 formed of a light-transmitting material, and a first base 62 provided at one end and the other end of the tube body 61 in the longitudinal direction. The second base 63, and the LED module 1 of the second modification is housed in the tube body 61. The LED module 1 is not limited to the LED module 1 of the second modification example, and the LED module 1 of any one of the first to third embodiments and the first modification example of the third embodiment is similar to the second modification example in the mounting substrate 7. May be configured to have a plurality of LED chips 4 with respect to one mounting substrate 7.

As the material of the tube body 61, for example, transparent glass, milky white glass, transparent resin, milky white resin, or the like can be used.

The first base 62 is provided with two power supply terminals (hereinafter referred to as “first lamp pins”) 64 and 64 electrically connected to the LED module 1. These two first lamp pins 64 and 64 are configured to be electrically connectable to the two power supply contacts of the power supply lamp socket held in the main body of the lighting equipment (not shown). Has been.

The second base 63 is provided with one ground terminal (hereinafter referred to as “second lamp pin”) 65 for grounding. The one second lamp pin 65 is configured to be electrically connectable to a grounding contact of a grounding lamp socket held in the instrument body.

Each of the first lamp pins 64 is formed in an L shape, and protrudes along the longitudinal direction of the tube main body 61, and from the tip of the pin main body 64a to one radial direction of the tube main body 61. And a key part 64b extending along the line. The two key parts 64b are extended in directions away from each other. Each first lamp pin 64 is formed by bending an elongated metal plate.

The second lamp pin 65 protrudes from the end face (base reference surface) of the second base 63 to the side opposite to the tube body 61. The second lamp pin 65 is formed in a T shape. The straight tube LED lamp 60 is, for example, a “straight tube LED lamp system with an L-shaped pin cap GX16t-5 (for general illumination)” (JEL 801: 2010) standardized by the Japan Light Bulb Industry Association. ) And the like.

In the straight tube type LED lamp 60 described above, the above-described LED module 1 is provided in the tube main body 61, so that it is possible to improve the light extraction efficiency, thereby reducing the cost and increasing the light output. Can be achieved.

The lamp provided with the LED module 1 is not limited to the straight tube LED lamp described above. For example, a straight tube LED having a configuration in which the LED module 1 and a lighting device for lighting the LED module 1 are provided in the tube body. A lamp may be used. The lighting device is supplied with power from an external power source via a lamp pin.

In the LED module 1 of the second modification, the mounting substrate 7 has an elongated shape and includes a plurality of LED chips 4. However, depending on the type of lighting fixture to be applied, the shape of the mounting substrate 7 and wiring The shape of the pattern 71, the number of LED chips 4, the arrangement, and the like can be changed as appropriate.

Below, one form of the lighting fixture 90 provided with the LED module 1 is demonstrated based on FIG. In addition, the same code | symbol is attached | subjected to the component similar to a 2nd modification, and description is abbreviate | omitted suitably.

The lighting fixture 90 is an LED lighting fixture that can be used as a downlight, and includes a fixture main body 91a and an LED module 1 that is a light source held by the fixture main body 91a. The lighting fixture 90 includes a rectangular box-shaped case 98 in which a lighting device for lighting the LED module 1 is housed. The lighting device and the LED module 1 are electrically connected by an electric wire (not shown).

The lighting fixture 90 has a fixture main body 91 formed in a disk shape, and the LED module 1 is disposed on one surface side of the fixture main body 91a. The lighting fixture 90 includes a plurality of fins 91ab protruding from the other surface of the fixture body 91. The instrument main body 91 and each fin 91ab are integrally formed.

In the LED module 1, the planar shape of the mounting substrate 7 is a square shape, and a plurality of (for example, 48) LED chips 4 (see FIG. 21) are arranged in a two-dimensional array. In addition, the LED module 1 includes a group (for example, eight) of LED chips 4 arranged on a virtual line connected in series. The LED module 1 assumes a specified number (for example, six) of virtual lines, and includes the specified number of series circuits in which a group of LED chips 4 are connected in series, and the specified number of series circuits are in parallel. The wiring pattern 71 is designed to be connected. Note that the planar shape of the mounting substrate 7 is not limited to a square shape, and may be, for example, a polygonal shape or a circular shape other than a square shape. Further, the electrical connection relationship of the plurality of LED chips 4 arranged on the one surface 7sa side of the mounting substrate 7 is not particularly limited. The LED module 1 may include the same number of light diffusion substrates 2 (see FIG. 21) as the LED chips 4, or one light diffusion substrate 2 for a group of LED chips 4. Also good.

The lighting fixture 90 includes a first reflector 93 that reflects light emitted from the LED module 1 to the side, a cover 92, and a second reflector 94 that controls the light distribution of the light emitted from the cover 92. ing. In addition, the lighting fixture 90 includes the fixture main body 91 and the second reflector 94 to form a fixture outline that houses the LED module 1, the first reflector 93, and the cover 92.

The instrument main body 91 is provided with two projecting base portions 91a facing each other on the one surface side. And as for the lighting fixture 90, the plate-shaped fixing member 95 which fixes the LED module 1 is constructed by the two protrusion parts 91a. The fixing member 95 is formed of sheet metal, and is fixed to each of the projecting base portions 91a by screws 97. The first reflector 93 is fixed to the instrument main body 91. The LED module 1 may be sandwiched between the first reflector 93 and the fixing member 95. The first reflector 93 is made of a white synthetic resin.

The fixing member 95 is formed with an opening 95a that exposes a part of the mounting substrate 7 of the LED module 1. In the lighting device 90, a heat conducting portion 96 is interposed between the mounting substrate 7 and the device main body 91. The heat conduction unit 96 has a function of transferring heat from the mounting substrate 7 to the instrument main body 91. Although the heat conductive part 96 is formed with heat conductive grease, it is not restricted to this, For example, you may use a heat conductive sheet.

As the thermally conductive sheet, a silicone gel sheet having electrical insulation and thermal conductivity can be used. The silicone gel sheet used as the heat conductive sheet is preferably soft. For example, Sarcon (registered trademark) can be used as this type of silicone gel sheet.

Further, the material of the heat conductive sheet is not limited to silicone gel, and may be, for example, an elastomer as long as it has electrical insulation and heat conductivity.

The lighting fixture 90 can efficiently transfer the heat generated in the LED module 1 to the fixture main body 91 through the heat conducting portion 96. Therefore, the lighting fixture 90 can efficiently dissipate heat generated in the LED module 1 from the fixture main body 91 and the fins 91ab.

The material of the instrument main body 91 and the fin 91ab is preferably a material having a high thermal conductivity, and more preferably a material having a higher thermal conductivity than the mounting substrate 7. Here, as a material of the instrument main body 91 and the fin 91ab, it is preferable to employ a metal having high thermal conductivity such as aluminum or copper.

As the material of the cover 92, for example, acrylic resin, polycarbonate resin, silicone resin, glass, or the like can be employed.

The cover 92 may be integrally provided with a lens unit (not shown) that controls the light distribution of the light emitted from the LED module 1.

As the material of the second reflector 94, for example, aluminum, stainless steel, resin, ceramic or the like can be used.

In the luminaire 90 described above, since the above-described LED module 1 is provided as a light source, it is possible to reduce the cost and increase the light output. Moreover, in the lighting fixture 90, the fixture main body 91 is good also as a structure which serves as the mounting substrate 7 of the LED module 1. FIG.

Claims (3)

1. A translucent light diffusing substrate, an LED chip bonded to one surface side of the light diffusing substrate via a transparent first bonding portion, and a color covering the LED chip on the one surface side of the light diffusing substrate A conversion unit and a mounting substrate disposed on the other surface side of the light diffusion substrate, and the color conversion unit is excited by the light emitted from the LED chip and has a color different from that of the LED chip. The mounting substrate includes an insulating member having electrical insulation, and a wiring pattern embedded in the insulating member and electrically connected to the LED chip. The LED module is a non-translucent member having diffuse reflectivity.
2. The LED chip is provided with a first electrode and a second electrode on one surface side in the thickness direction, and each of the first electrode and the second electrode is electrically connected via the wiring pattern and a wire. The LED module according to claim 1, wherein the LED module is connected and a part of the wiring pattern is provided in a vertical projection region of the light diffusion substrate toward the mounting substrate.
3. The light diffusing substrate is embedded in the insulating member, and a side surface and the other surface are in contact with the insulating member. The mounting substrate has the wiring pattern provided on the one surface of the light diffusing substrate. The wiring pattern has the other end of each wire joined to the first electrode and the second electrode, and the part is joined, and the color converter is The LED module according to claim 2, wherein the LED chip and each of the wires are covered on the one surface side of the light diffusion substrate.

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