JP2017174742A - Luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminaire capable of achieving improvement of optical characteristics even in the case where the temperature of a light emitting part becomes high.SOLUTION: A luminaire includes: a housing for performing heat radiation by natural air cooling; a substrate provided at the housing; a light emitting diode which is provided at the substrate and whose temperature becomes equal to or higher than 150°C during lighting time; and a phosphor layer provided on the light radiation side of the light emitting diode and including nitride phosphor. When a light diminishing ratio when the temperature of the nitride phosphor is at 100°C is defined as A, and a light diminishing ratio when the temperature of the nitride phosphor is at 300°C is defined as B, B/A becomes equal to or greater than 0.9.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a lighting device.

Even a high-power (high watt) lighting device such as a projector or a spotlight is generally cooled by natural air cooling. Natural air cooling has lower heat dissipation performance than forced air cooling. In this case, the heat dissipation performance can be improved by increasing the size of the housing in which the light emitting module (light source) is provided. However, since a predetermined restriction may be imposed on the external dimensions of the lighting device, the size of the housing may not be increased. Further, when the size of the casing is increased, a temperature distribution is generated, and the heat dissipation efficiency may be reduced. For this reason, there is a limit to increasing the size of the housing. In such an illuminating device, when the output of the illuminating device is increased, the temperature of the light emitting unit provided in the light emitting module is increased, and there is a possibility that optical characteristics such as color misregistration and color unevenness are deteriorated.
Therefore, it has been desired to develop a lighting device that can improve the optical characteristics even when the temperature of the light emitting unit is increased.

JP 2014-235820 A

  The problem to be solved by the present invention is to provide an illuminating device capable of improving optical characteristics even when the temperature of the light emitting portion is increased.

An illumination device according to an embodiment includes a housing that performs heat radiation by natural air cooling; a substrate provided in the housing; a light-emitting diode that is provided on the substrate and has a temperature of 150 ° C. or more when turned on; and the light-emitting diode And a phosphor layer including a nitride phosphor provided on the light emission side.
B / A is 0.9 or more, where A is the extinction rate when the temperature of the nitride phosphor is 100 ° C. and B is the extinction rate when the temperature of the nitride phosphor is 300 ° C. It becomes.

  According to the embodiment of the present invention, it is possible to provide an illumination device capable of improving the optical characteristics even when the temperature of the light emitting unit is increased.

It is a schematic fragmentary sectional view for illustrating lighting device 100 concerning this embodiment. 1 is a schematic cross-sectional view of a light emitting module 1. FIG. It is a graph for demonstrating the relationship between the temperature of a fluorescent substance, and a light attenuation rate.

The invention according to the embodiment includes: a housing that radiates heat by natural air cooling; a substrate provided in the housing; a light-emitting diode that is provided on the substrate and has a temperature of 150 ° C. or more when lit; A phosphor layer including a nitride phosphor provided on the light emission side, wherein A is the light attenuation rate when the temperature of the nitride phosphor is 100 ° C., and the temperature of the nitride phosphor is When the light attenuation rate at 300 ° C. is B, the illumination device has B / A of 0.9 or more.
If a nitride phosphor having a B / A of 0.9 or more is used, even if the temperature of the nitride phosphor becomes 100 ° C. or more, it becomes easy to suppress the occurrence of color misregistration, color unevenness and the like. .
That is, even when the temperature of the light emitting portion having the phosphor layer is increased, the optical characteristics can be improved.

The light-emitting diode may contain gallium nitride and have a peak wavelength shift amount of 5 nm or more and 20 nm or less at the same current value in a temperature range of 150 ° C. or more and 250 ° C. or less.
In this way, even if the temperature of the light emitting diode becomes 150 ° C. or higher, it becomes easy to suppress the occurrence of color misregistration, color unevenness and the like.

Moreover, this illuminating device can further be provided with the junction part provided between the said board | substrate and the said light emitting diode and containing a sintered metal body.
In this way, heat generated in the light emitting diode can be efficiently transferred to the substrate.

The sintered metal body may contain silver nanoparticles.
In this way, the heat generated in the light emitting diode can be more efficiently transmitted to the substrate, so that the temperature of the light emitting diode and the nitride phosphor can be suppressed from increasing.

Moreover, the output of the said illuminating device can be 200 W (watt) or more.
Even if the temperature of the light emitting portion is increased due to such a high output lighting device, the optical characteristics can be improved.

  Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.

(Lighting device)
FIG. 1 is a schematic partial cross-sectional view for illustrating a lighting device 100 according to the present embodiment. FIG. 2 is a schematic cross-sectional view of the light emitting module 1.
The lighting device 100 illustrated in FIG. 1 is a projector installed in a building or a stadium. However, the illumination device 100 is not limited to a projector. For example, the lighting device 100 can have an output of 200 W (watts) or more.

As shown in FIG. 1, the lighting device 100 includes a light emitting module 1, an irradiation unit 110, and a light source unit 120.
As shown in FIG. 2, the light emitting module 1 includes a substrate 10, a light emitting unit 20, a bonding unit 30, a frame unit 40, and a sealing unit 50.

The substrate 10 has a base 11 and a wiring pattern 12.
The base 11 has a plate shape.
In the case of the lighting device 100 having an output of 200 W (watts) or more, the base 11 is preferably formed using a material having high thermal conductivity. The material having high thermal conductivity can be, for example, an inorganic material such as ceramics (for example, aluminum oxide or aluminum nitride), or a metal plate whose surface is covered with an insulating material. When the surface of the metal plate is covered with an insulating material, the insulating material may be made of an organic material or an inorganic material.

  The wiring pattern 12 includes a mounting pad 12a, a wiring portion 12b, and an input terminal 12c. The mounting pad 12 a is provided on one surface of the base body 11. The mounting pad 12 a is provided inside the frame portion 40. One set of mounting pads 12 a is provided for one light emitting unit 20. The wiring part 12b is provided on the surface of the base 11 on which the mounting pad 12a is provided. One end of the wiring part 12 b is provided inside the frame part 40. One end of the wiring part 12b is electrically connected to the mounting pad 12a. The other end of the wiring part 12 b is provided outside the frame part 40. The other end of the wiring portion 12b is electrically connected to the input terminal 12c.

  The input terminal 12c is provided on the surface of the base 11 on which the mounting pad 12a is provided. The input terminal 12 c is provided outside the frame portion 40. The input terminal 12c is electrically connected to a power source, a control device (not shown) provided outside the light emitting module 1 and the like. Therefore, the plurality of light emitting units 20 are electrically connected to a power source, a control device, and the like (not shown) via the input terminal 12c.

  The material of the wiring pattern 12 is not particularly limited as long as it is a conductive material. The material of the wiring pattern 12 can be a metal such as silver, copper, gold, or tungsten, for example. When the material of the base 11 is ceramic, the substrate 10 can be formed using, for example, the LTCC (Low Temperature Co-fired Ceramics) method. For example, the substrate 10 can be formed by simultaneously firing the base 11 and the wiring pattern 12 at a temperature of 900 ° C. or lower.

The light emitting unit 20 includes a light emitting diode 21 and a phosphor layer 22.
The light emitting diode 21 is mounted on the mounting pad 12a using a COB (Chip on Board) method. The light emitting diode 21 can be, for example, a flip chip type light emitting diode.
Here, in the upper and lower electrode type light emitting diode, the light emitting layer for generating light is provided on the opposite side (upper side) to the substrate 10 side in the light emitting diode. On the other hand, in the flip-chip type light emitting diode, the light emitting layer for generating light is provided on the substrate 10 side (lower side) inside the light emitting diode. The light emitting layer provided in the light emitting diode 21 serves as a heat source. Therefore, heat dissipation can be improved by using a flip chip type light emitting diode in which a light emitting layer serving as a heat source is provided closer to the substrate 10.

  In the case of the lighting device 100 having an output of 200 W (watts) or more, the temperature of the light emitting diode 21 can be 150 ° C. or more at the time of lighting. As the temperature of the light emitting diode 21 increases, the shift amount of the peak wavelength increases, and color misregistration, color unevenness and the like are likely to occur. Therefore, the light emitting diode 21 preferably has a peak wavelength shift amount within a predetermined range in a temperature range of 150 ° C. or higher and 250 ° C. or lower. For example, the light emitting diode 21 emits blue light, and the peak wavelength shift amount at the same current value is preferably 5 nm or more and 20 nm or less in a temperature range of 150 ° C. or more and 250 ° C. or less. . In this way, even if the illumination device 100 has an output of 200 W (watts) or more, it is possible to suppress occurrence of color misregistration, color unevenness, and the like.

The light emitting diode 21 can include, for example, gallium nitride (GaN). However, even a light emitting diode containing gallium nitride (GaN) does not satisfy the above-described characteristics.
Therefore, in the case of the lighting device 100 with an output of 200 W (watts) or more, the light emitting diode 21 contains gallium nitride (GaN) and has a peak wavelength at the same current value in a temperature range of 150 ° C. or more and 250 ° C. or less. The shift amount is more preferably 5 nm or more and 20 nm or less.

  The number, arrangement, interval, size, and the like of the light-emitting diodes 21 are not limited to those illustrated, and can be changed as appropriate according to the application and size of the lighting device 100.

The phosphor layer 22 is provided on the light emission side of the light emitting diode 21.
In FIG. 2, the phosphor layer 22 provided on the light emitting surface of the light-emitting diode 21 is illustrated, but the phosphor layer 22 that integrally covers the plurality of light-emitting diodes 21 may be used. Further, the phosphor layer 22 and the sealing portion 50 may be integrated. That is, a phosphor may be included in the sealing unit 50 to form a phosphor layer. That is, the phosphor layer 22 only needs to be provided on the light emission side of the light emitting diode 21.

The phosphor layer 22 contains a phosphor.
As described above, in the case of the lighting device 100 having an output of 200 W (watts) or more, the temperature of the light emitting diode 21 can be 150 ° C. or more during lighting. Therefore, the temperature of the phosphor can be 150 ° C. or higher. If the temperature of the phosphor is increased, the reduction rate of the light attenuation rate may increase.
In the present specification, the “dimming rate” means the rate of reduction of the total luminous flux taking into account the light conversion efficiency (external quantum efficiency) by the phosphor when white light is formed as a light source. Therefore, when the decrease rate of the light attenuation rate increases, the total luminous flux (brightness) decreases and the decrease rate increases, so that the phosphor loss increases and the amount of heat generated by the phosphor increases. As a result, the peak wavelength of the light emitting diode shifts due to the temperature dependence of the light emitting diode, and color misregistration, color unevenness and the like are likely to occur.
The dimming rate can be obtained, for example, as dimming rate = total luminous flux × (phosphor) external quantum efficiency.

FIG. 3 is a graph for illustrating the relationship between the temperature of the phosphor and the light attenuation rate.
As can be seen from FIG. 3, as the temperature of the phosphor increases, the light attenuation rate decreases.
In this case, when the phosphor is a YAG (Yttrium Aluminum Garnet) phosphor, when the temperature of the phosphor becomes 100 ° C. or higher, the light attenuation rate rapidly decreases.
On the other hand, when the phosphor is a nitride phosphor, even if the temperature of the phosphor becomes 100 ° C. or higher, it is possible to suppress a decrease in the light attenuation rate.
Therefore, in the case of the lighting device 100 with an output of 200 W (watts) or more, the phosphor is preferably a nitride phosphor.
Nitride phosphor is, for example, sialon-based nitride phosphor, CaAlSiN ₃ generates yellow fluorescence: Eu (CACSN), CaAlSiN ₃ generates red _{fluorescence: Eu (CASN), La 3} Si 6 N 11 ( LSN).

However, even a nitride phosphor may have a large reduction rate of the light attenuation rate.
Therefore, in the case of the lighting device 100 with an output of 200 W (watts) or more, the light attenuation rate when the temperature of the nitride phosphor is 100 ° C. is A, and the light attenuation when the temperature of the nitride phosphor is 300 ° C. When the rate is B, a nitride phosphor having a B / A of 0.9 or more is preferable. If a nitride phosphor having a B / A of 0.9 or more is used, it is easy to suppress the occurrence of color misregistration, color unevenness, and the like.

The joint portion 30 is provided between the light emitting diode 21 and the substrate 10 (mounting pad 12a). The junction 30 mechanically and electrically connects the light emitting diode 21 and the mounting pad 12a. The joint portion 30 can have a high thermal conductivity and electrical conductivity and a high melting point. The joining part 30 can use a sintered metal body, for example.
If it is set as the junction part 30 using a sintered metal body, the heat generated in the light emitting diode 21 can be efficiently transmitted to the substrate 10.

  In the case of the lighting device 100 with an output of 200 W (watts) or more, it is more preferable to use a sintered metal body containing silver nanoparticles. If the sintered metal body containing silver nanoparticles is used, the heat generated in the light emitting diode 21 can be transmitted to the substrate 10 more efficiently, so that the temperature of the light emitting diode 21 and the phosphor can be prevented from increasing. .

  The frame part 40 has a frame shape. The frame part 40 is provided on the surface of the substrate 10 on which the light emitting part 20 is provided. The frame part 40 is provided so as to surround the plurality of light emitting parts 20. The frame portion 40 can be formed of, for example, a resin such as PBT (polybutylene terephthalate) or PC (polycarbonate), ceramics, or the like.

  Further, when the material of the frame part 40 is a resin, particles made of titanium oxide or the like can be mixed to improve the reflectance with respect to the light emitted from the light emitting part 20. The particles are not limited to titanium oxide particles, and particles made of a material having a high reflectance with respect to the light emitted from the light emitting unit 20 may be mixed. Moreover, the frame part 40 can also be formed from white resin, for example. That is, the frame part 40 can have a function of defining a region where the sealing part 50 is formed and a function of a reflector. In addition, the shape of the frame part 40 is not necessarily limited to what was illustrated, and can be changed suitably.

  Moreover, the frame part 40 is not necessarily required and can be omitted. In addition, when the frame part 40 is not provided, the shape of the sealing part 50 can be made into dome shape etc., for example.

The sealing part 50 is provided inside the frame part 40. When the upper surface 50a of the sealing part 50 is a flat surface, it is preferable that the height of the sealing part 50 be lower than the height of the frame part 40. If it does in this way, when supplying resin mentioned below, it can control that resin overflows outside the frame part 40. FIG. The sealing unit 50 is provided so as to cover the plurality of light emitting units 20. The height dimension of the sealing part 50 can be about 2 to 5 times the thickness dimension of the light emitting diode 21, for example. In addition, the thickness dimension of the light emitting diode 21 can be about 0.1 mm.
Moreover, the upper surface 50a of the sealing part 50 can also be made into a dome-shaped curved surface, for example.

  The sealing part 50 is formed from a material having translucency. The sealing part 50 can be formed from transparent resins, such as silicone resin, for example. In this case, it is preferable to form the sealing part 50 from methyl silicone resin. This is because methyl silicone resin has heat resistance and flexibility. In this case, the hardness of the methyl silicone resin is preferably about Shore A20 to A40. If the sealing part 50 is formed from a methyl silicone resin, it is possible to improve heat resistance and relieve generated thermal stress.

The irradiation unit 110 includes a housing 111 and a reflector 112.
The casing 111 has a box shape. The casing 111 can be formed from, for example, an aluminum alloy. The end of the housing 111 opposite to the light source 120 side is open. This opening is closed by a translucent cover (not shown). A hole 111 a is provided at the end of the housing 111 on the light source unit 120 side.

  The reflector 112 is provided inside the housing 111. A flange 112a that protrudes outward is provided at the end of the reflector 112 opposite to the light source 120 side. The flange 112 a is fixed to a mounting plate (not shown) provided on the inner wall of the housing 111.

  The reflector 112 can be a cylindrical body having both ends opened. The reflector 112 has a form in which the cross-sectional dimension gradually decreases toward the light source unit 120 side. The inner surface of the reflector 112 is a mirror surface. The end of the reflector 112 on the light source unit 120 side is provided inside the hole 111a. An end of the reflector 112 on the light source unit 120 side is provided at a position facing the light emitting module 1. For example, a hemispherical lens may be disposed on the light emission side of the light emitting module 1. Further, the light exit surface of the lens can be subjected to a diffusion treatment or a diffusion sheet can be attached. If the diffusion treatment is performed or the diffusion sheet is attached, the light emitted from the light emitting module 1 can be diffused, so that the occurrence of color unevenness can be further suppressed.

The light source unit 120 includes a housing 121, an attachment unit 122, a heat radiating unit 123, a packing 124, a heat radiating fin 125, a heat pipe 126, and a joint 127.
The housing 121 radiates heat by natural air cooling using the radiating fins 125 and the heat pipe 126. The housing 121 has a box shape. The housing 121 can be formed from, for example, an aluminum alloy. A hole is provided at the end of the housing 121 on the irradiation unit 110 side. Inside the hole portion, the light emitting module 1 attached to the attachment portion 122 is provided. That is, the substrate 10 is provided in the housing 121.

  The attachment portion 122 has a plate shape. The attachment portion 122 can be formed from, for example, an aluminum alloy. The attachment portion 122 is attached to the heat dissipation portion 123 using a fastening member such as a screw. A concave portion is provided on the end surface of the mounting portion 122 on the irradiation unit 110 side. Inside the concave portion, the light emitting module 1 is provided via a joint portion 127.

The heat dissipation part 123 has a plate shape. The heat dissipation part 123 can be formed from, for example, an aluminum alloy. The heat radiating part 123 is attached to the inside of the housing 121 using a fastening member such as a screw (not shown).
The packing 124 has an annular shape. The packing 124 is provided between the heat radiating portion 123 and the inner wall surface of the housing 121.

  The radiation fin 125 has a thin plate shape. A plurality of radiating fins 125 are provided. The heat radiation fins 125 can be formed from, for example, an aluminum alloy. The heat radiating fins 125 are provided on the surface of the heat radiating portion 123 opposite to the side on which the mounting portion 122 is provided.

The heat pipe 126 is provided between the heat radiating part 123 and the heat radiating fins 125. A plurality of heat pipes 126 can be provided.
In addition, a control device (not shown) for controlling the light emitting module 1 can be provided. For example, the control device controls turning on and off of the light emitting diode 21. Further, the control device controls the power supplied to the light emitting diode 21 to control the light emission output of the light emitting diode 21.

The joint portion 127 is provided between the light emitting module 1 and the bottom surface of the concave portion of the attachment portion 122. The joint portion 127 mechanically connects the light emitting module 1 and the attachment portion 122. The joint 127 can have a high thermal conductivity. The joining part 127 can use a sintered metal body, for example.
If the joined portion 127 using a sintered metal body is used, the heat generated in the light emitting diode 21 can be efficiently transmitted to the radiation fins 125 and the heat pipe 126.

  In the case of the lighting device 100 with an output of 200 W (watts) or more, it is more preferable to use a sintered metal body containing silver nanoparticles. If the sintered metal body containing silver nanoparticles is used, the heat generated in the light emitting diode 21 can be more efficiently transferred to the heat radiation fins 125 and the heat pipe 126, so that the temperature of the light emitting diode 21 and the phosphor increases. Can be suppressed.

(Manufacturing method of lighting device)
Next, a method for manufacturing the lighting device 100 will be illustrated.
First, the material of the base 11, the material and temperature characteristics of the light emitting diode 21, the phosphor material and the reduction rate of the light attenuation rate are made to satisfy the above-described ones.
For example, the material of the base 11 is ceramics.
The light-emitting diode 21 contains gallium nitride (GaN) and has a peak wavelength shift amount of 5 nm or more and 20 nm or less at the same current value in a temperature range of 150 ° C. or more and 250 ° C. or less.
The phosphor has a B / A of 0.9 or more, where A is the light extinction rate when the phosphor temperature is 100 ° C. and B is the light extinction rate when the phosphor temperature is 300 ° C. A nitride phosphor is used.

Next, the plurality of light emitting units 20 are mounted on the substrate 10 having the wiring pattern 12.
At this time, for example, a silver nano paste is applied onto the mounting pad 12a using a screen printing method or the like. Subsequently, the light emitting part 20 is placed on the applied silver nanopaste, and a heat treatment is performed to form a joining part 30 made of a sintered metal body, and the light emitting diode 21 and the mounting pad 12a are mechanically connected. And connect electrically.

  Next, the frame part 40 is provided so that the some light emission part 20 may be enclosed. In this case, the frame-shaped frame portion 40 may be bonded to the substrate 10, or a resin may be applied to the substrate 10 in a frame shape and cured.

Next, a resin having translucency is supplied inside the frame portion 40 to form the sealing portion 50.
For example, the resin can be supplied using a liquid dispensing apparatus such as a dispenser. At this time, the shape of the upper surface 50a of the sealing portion 50 is controlled by adjusting the viscosity of the resin to be supplied. For example, by supplying a resin having a low viscosity, the upper surface 50a of the sealing portion 50 is made flat. For example, by supplying a resin having a high viscosity, the upper surface 50a of the sealing portion 50 is made to be a dome-shaped curved surface. Note that the viscosity of the resin to be supplied can be determined, for example, by conducting experiments or simulations in advance.
As described above, the light emitting module 1 can be manufactured.

  Next, for example, silver nano paste is applied to the bottom surface of the concave portion of the attachment portion 122. Subsequently, the light emitting module 1 is placed on the coated silver nanopaste, and a heat treatment is performed to form a joining portion 127 made of a sintered metal body. The light emitting module 1 and the mounting portion 122 are mechanically connected. Connect to.

Next, the housing 111, the reflector 112, the housing 121, the attachment portion 122 provided with the light emitting module 1, the heat radiating portion 123, the packing 124, the heat radiating fins 125, and the heat pipe 126 are sequentially assembled.
The lighting device 100 can be manufactured as described above.

  As mentioned above, although several embodiment of this invention was illustrated, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, and the like can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and equivalents thereof. Further, the above-described embodiments can be implemented in combination with each other.

  DESCRIPTION OF SYMBOLS 1 Light emitting module, 10 board | substrate, 12 wiring pattern, 12a mounting pad, 20 light emission part, 21 light emitting diode, 22 fluorescent substance layer, 30 junction part, 100 lighting apparatus, 121 housing | casing, 127 junction part

Claims (5)

A housing that dissipates heat by natural air cooling;
A substrate provided in the housing;
A light emitting diode provided on the substrate and having a temperature of 150 ° C. or higher when lit;
A phosphor layer including a nitride phosphor provided on the light emitting side of the light emitting diode;
Comprising
B / A is 0.9 or more, where A is the extinction rate when the temperature of the nitride phosphor is 100 ° C. and B is the extinction rate when the temperature of the nitride phosphor is 300 ° C. A lighting device.   2. The lighting device according to claim 1, wherein the light-emitting diode contains gallium nitride, and a shift amount of a peak wavelength at the same current value is 5 nm or more and 20 nm or less in a temperature range of 150 ° C. or more and 250 ° C. or less.   The lighting device according to claim 1, further comprising a joint provided between the substrate and the light emitting diode and including a sintered metal body.   The lighting device according to claim 3, wherein the sintered metal body includes silver nanoparticles.   The output of the said illuminating device is 200 W (watt) or more, The illuminating device as described in any one of Claims 1-4.

Images