JP2017116719A - Light emitter and luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress size increase of a light emitter and enhance heat radiation efficiency on the light emitter.SOLUTION: A light emitter 4 comprises: a phosphor layer 43 containing at least one kind of a phosphor (phosphor particle 431); a substrate 41 having heat conductivity higher than that of the phosphor layer 43, on whose one main surface 411 the phosphor layer 43 is arranged; and a joint part 42 interposed between the phosphor layer 43 and the substrate 41 for metal jointing the phosphor layer 43 and the substrate 41. A through hole 5 continuous to a direction crossing the main surface 411 of the substrate 41 is formed on the substrate 41 and the joint part 42. The through hole 5 excites the phosphor, so that the through hole serves as a light path of an excitation light entering from the substrate 41 side.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a light emitting element in which a phosphor layer is laminated on a substrate, and an illumination device including the same.

  Conventionally, a phosphor layer is irradiated with a laser beam transmitted by a light guide member as excitation light to a light emitting element in which a phosphor layer is laminated on a substrate, so that the phosphor layer emits light and is converted into a desired light color. There is an illuminating device for illuminating (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2015-65142

  In recent years, it has been desired to more efficiently dissipate heat generated in the phosphor layer. Although it is conceivable to increase the heat dissipation area by enlarging the light emitting element, it is not preferable because the lighting device itself is increased in size.

  In view of the above, an object of the present invention is to increase heat dissipation efficiency in a light emitting element while suppressing an increase in size of the light emitting element.

  A light-emitting element according to one embodiment of the present invention includes a phosphor layer including at least one kind of phosphor and a substrate having higher thermal conductivity than the phosphor layer, and the phosphor layer is disposed on one main surface side. And a bonding portion that is interposed between the phosphor layer and the substrate and metal-bonds the phosphor layer and the substrate, and the substrate and the bonding portion are arranged in a direction intersecting the main surface of the substrate. A continuous through hole is formed, and the through hole is an optical path of excitation light incident from the substrate side for exciting the phosphor.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal radiation efficiency in a light emitting element can be improved, suppressing the enlargement of a light emitting element.

It is a schematic diagram which shows schematic structure of the illuminating device which concerns on embodiment. It is sectional drawing which shows schematic structure of the light emitting element which concerns on embodiment. It is sectional drawing which shows the state before the assembly of the light emitting element which concerns on embodiment. FIG. 6 is a cross-sectional view illustrating a schematic configuration of a light emitting element according to Modification 1. 12 is a cross-sectional view illustrating a schematic configuration of a light emitting device according to Modification 2. FIG. 14 is a cross-sectional view illustrating a schematic configuration of a light emitting device according to Modification 3. FIG. 14 is a cross-sectional view illustrating a schematic configuration of a light-emitting element according to Modification 4. FIG.

  Below, the light emitting element which concerns on embodiment of this invention is demonstrated using drawing. Note that each of the embodiments described below shows a preferred specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement of components, connection forms, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.

  Each figure is a mimetic diagram and is not necessarily illustrated strictly. Moreover, in each figure, the same code | symbol is attached | subjected about the same structural member.

  Hereinafter, embodiments will be described.

[Lighting device]
First, the illumination device according to the embodiment will be described.

  FIG. 1 is a schematic diagram illustrating a schematic configuration of a lighting apparatus according to an embodiment.

  As shown in FIG. 1, the lighting device 1 includes a light source unit 2, a light guide member 3, and a light emitting element 4.

  The light source unit 2 is a device that generates laser light and supplies the laser light to the light emitting element 4 via a light guide member 3 such as an optical fiber. For example, the light source unit 2 is a semiconductor laser element that emits laser light having a wavelength of bluish purple to blue (430 to 490 nm).

  The light emitting element 4 is a light emitting element that emits white light to the front surface side using the laser light transmitted from the light guide member 3 and irradiated from the back side of the light emitting element 4 as excitation light.

[Light emitting element]
Hereinafter, the light emitting element 4 will be described in detail.

  FIG. 2 is a cross-sectional view illustrating a schematic configuration of the light-emitting element 4 according to the embodiment.

  As shown in FIG. 2, the light emitting element 4 includes a substrate 41, a bonding portion 42, and a phosphor layer 43.

  The substrate 41 is a substrate whose planar view shape is, for example, a rectangular shape or a circular shape. The substrate 41 is a substrate having higher thermal conductivity than the phosphor layer 43. Thereby, the heat conducted from the phosphor layer 43 can be efficiently radiated from the substrate 41. Specifically, the substrate 41 is made of a metal material such as Cu or Al. The substrate 41 may be made of a material other than a metal material as long as it has a higher thermal conductivity than the phosphor layer 43. Examples of the material other than the metal material include glass and sapphire. In addition, a heat sink such as a mirror surface heat sink may be in contact with and attached to the substrate 41 in order to further improve heat dissipation.

  The phosphor layer 43 is disposed on one main surface 411 side of the substrate 41 with the joint portion 42 interposed therebetween. The phosphor layer 43 is formed in the same shape as the substrate 41 in plan view. The phosphor layer 43 includes, for example, phosphor particles (phosphor particles 431) that emit fluorescence when excited by laser light in a dispersed state, and the phosphor particles 431 emit fluorescence when irradiated with laser light. . For this reason, the outer main surface of the phosphor layer 43 becomes a light emitting surface.

  In the case of the present embodiment, the phosphor layer 43 emits white light, and a first phosphor that emits red light, a second phosphor that emits blue light, and a third phosphor that emits green light. Three types of phosphor particles of the phosphor are included at an appropriate ratio.

  The type and characteristics of the phosphor are not particularly limited. However, since a relatively high-power laser beam serves as excitation light, it is desirable to have a high heat resistance. In addition, the type of the substrate that holds the phosphor in a dispersed state is not particularly limited, but the substrate should be highly transparent with respect to the wavelength of the excitation light and the wavelength of the light emitted from the phosphor. desirable. Specifically, the base material which consists of glass or ceramics is mentioned.

  Further, the phosphor layer 43 may be a polycrystal or a single crystal made of one kind of phosphor.

  The bonding part 42 includes a first electrode layer 421, a second electrode layer 422, and a metal bonding layer 423.

  The first electrode layer 421 is stacked on the main surface 411 of the substrate 41 on the phosphor layer 43 side. The first electrode layer 421 is made of a metal material such as Au, Ag, Ni, Pd, Ti, for example. The first electrode layer 421 is formed by forming a metal material on the main surface 411 of the substrate 41 by a known film forming method such as sputtering or plating.

  The second electrode layer 422 is stacked on the main surface 432 of the phosphor layer 43 on the substrate 41 side. The second electrode layer 422 is made of a metal material such as Au, Ag, Ni, Pd, Ti, for example. The second electrode layer 422 is formed by depositing a metal material on the main surface 432 of the phosphor layer 43 by a film forming method such as sputtering or plating.

  The metal bonding layer 423 is laminated on the main surface 4211 on the phosphor layer 43 side in the first electrode layer 421 and the main surface 4221 on the substrate 41 side in the second electrode layer 422. The metal bonding layer 423 is formed of a metal material capable of metal bonding. Examples of metal materials that can be metal-bonded include AuSn-based, AuGe-based, and SnAgCu-based solder materials.

  Here, the state before the assembly of the light emitting element 4 will be described.

  FIG. 3 is a cross-sectional view illustrating a state before assembly of the light-emitting element 4 according to the embodiment.

  As shown in FIG. 3, before the light emitting element 4 is assembled, the first electrode layer 421 is integrated with the substrate 41 in advance, and the second electrode layer 422 and the solder material 423a are combined with the phosphor layer 43. Are integrated in advance. Then, after the first electrode layer 421 is brought into contact with the solder material 423a, the solder material 423a is melted by heating, and the first electrode layer 421 and the second electrode layer 422 are metal-bonded. As a result, the solder material is interposed between the first electrode layer 421 and the second electrode layer 422, thereby forming the metal bonding layer 423 that bonds the first electrode layer 421 and the second electrode layer 422.

  Before assembling the light emitting element 4, the solder material 423 a may be integrated with the second electrode layer 422 in advance. Further, the solder material 423a may be a separate body from the first electrode layer 421 and the second electrode layer 422, and may be attached to the first electrode layer 421 and the second electrode layer 422 at the time of assembly.

  After metal bonding, as shown in FIG. 2, through-holes 5 that are continuous in the normal direction of the main surface 411 of the substrate 41 are formed in the substrate 41 and the bonding portion 42. The through hole 5 serves as an optical path for laser light incident from the substrate 41 side in order to excite the phosphor particles 431 of the phosphor layer 43. Note that the through hole 5 may not be formed after metal bonding, but may be formed in advance in the substrate 41, the first electrode layer 421, the solder material 423a, and the second electrode layer 422 before metal bonding.

  Here, the through hole 5 may be continuous in any direction as long as it intersects the main surface 411. Further, the through hole 5 may have any shape as long as it does not hinder the progress of the laser beam.

[Operation of lighting device]
Next, operation | movement of the illuminating device 1 is demonstrated.

  When laser light is irradiated from the light source unit 2 through the light guide member 3 into the through hole 5 of the light emitting element 4, the laser light passes through the through hole 5 and enters the phosphor layer 43. Laser light hitting the phosphor particles 431 in the phosphor layer 43 is converted into white light by the phosphor particles 431 and emitted from the phosphor layer 43.

  During the irradiation of the laser light, the phosphor particles 431 generate heat, but the heat is transmitted to the substrate 41 through the bonding portion 42 and radiated.

[Effects, etc.]
As described above, according to the present embodiment, the illumination device 1 includes the light emitting element 4 and the light source unit 2 that emits excitation light for exciting the phosphor particles 431 of the light emitting element 4. The light emitting element 4 has a phosphor layer 43 including at least one kind of phosphor particles 431 and a higher thermal conductivity than the phosphor layer 43, and the phosphor layer 43 is arranged on one main surface 411 side. A substrate 41 and a bonding part 42 for metal bonding between the phosphor layer 43 and the substrate 41 are provided between the phosphor layer 43 and the substrate 41. The substrate 41 and the joint portion 42 are formed with through holes 5 that are continuous in a direction intersecting the main surface 411 of the substrate 41. The through-hole 5 serves as an optical path for laser light incident from the substrate 41 side in order to excite the phosphor particles 431.

  Here, when the fluorescent substance layer 43 and the board | substrate 41 are adhere | attached with resin, the resin will become a thermal barrier and heat dissipation efficiency will fall. However, as described above, since the substrate 41 having a higher thermal conductivity than the phosphor layer 43 and the phosphor layer 43 are metal-bonded by the bonding portion 42, the phosphor layer 43 smoothly transfers to the substrate 41. It can heat and can improve heat dissipation efficiency.

  And since the through-hole 5 used as the optical path of the laser beam which injects from the board | substrate 41 side is formed in the board | substrate 41 and the junction part 42, white light can be discharge | released in the advancing direction of a laser beam. Moreover, since the light source part 2 and the light guide member 3 can be arrange | positioned at the back side of the board | substrate 41, the illuminating device 1 whole can be made compact.

  In addition, what is necessary is just to make the whole thermal conductivity of the junction part 42 higher than the fluorescent substance layer 43 in order to raise heat dissipation efficiency more. Specifically, the first electrode layer 421, the second electrode layer 422, and the metal bonding layer 423 that form the bonding portion 42 may be formed of a material having a higher thermal conductivity than the phosphor layer 43.

  The bonding portion 42 includes a first electrode layer 421 stacked on the main surface 411 of the substrate 41, a second electrode layer 422 stacked on the main surface 432 of the phosphor layer 43 on the substrate 41 side, and a first electrode. A metal bonding layer 423 that is interposed between the layer 421 and the second electrode layer 422 and bonds the first electrode layer 421 and the second electrode layer 422;

  Thus, since the metal bonding layer 423 is sandwiched between the first electrode layer 421 and the second electrode layer 422, by applying a current to the first electrode layer 421 and the second electrode layer 422 at the time of manufacture, Metal bonding by the metal bonding layer 423 can be easily realized.

[Modification 1]
Next, Modification 1 according to the present embodiment will be described.

  FIG. 4 is a cross-sectional view illustrating a schematic configuration of a light emitting element 4A according to Modification Example 1, and specifically corresponds to FIG. In the following description, the same parts as those of the light-emitting element 4 according to the embodiment are denoted by the same reference numerals, the description thereof is omitted, and only different parts are described.

  As shown in FIG. 4, the light emitting element 4 </ b> A of the first modification is obtained by adding a reflective layer 44 to the light emitting element 4 of the above embodiment. Specifically, the reflective layer 44 is laminated so as to cover the through hole 5 with respect to the main surface 432 on the substrate 41 side in the phosphor layer 43. That is, the reflective layer 44 is interposed between the phosphor layer 43 and the joint portion 42. The reflective layer 44 is a dichroic mirror that transmits laser light and reflects light emitted from the phosphor particles 431, and is, for example, a dielectric multilayer film.

  Since such a reflective layer 44 is provided in the light emitting element 4 </ b> A, the laser light incident from the through hole 5 can enter the phosphor layer 43 without being blocked. Further, the white light emitted from the phosphor particles 431 can be reflected by the reflection layer 44 and emitted to the outside of the phosphor layer 43. That is, since the white light that can be absorbed by the joint portion 42 without the reflective layer 44 can be emitted outward by the reflective layer 44, the luminous efficiency can be increased. Moreover, the heat_generation | fever by absorbing white light can also be suppressed.

[Modification 2]
Next, Modification 2 according to the present embodiment will be described.

  FIG. 5 is a cross-sectional view illustrating a schematic configuration of a light emitting element 4B according to Modification Example 2, and specifically corresponds to FIG.

  As illustrated in FIG. 5, the light emitting element 4 </ b> B of the second modification is obtained by adding a reflection suppressing layer 45 to the light emitting element 4 </ b> A of the first modification. Specifically, the reflection suppressing layer 45 is laminated on the main surface 441 on the substrate 41 side in the reflecting layer 44 so as to cover the through hole 5. The reflection suppression layer 45 transmits laser light and suppresses the transmitted laser light from being reflected by the main surface 441 of the reflection layer 44. An example of the antireflection layer 45 is an AR coating layer. The AR coat layer is formed of a material having a refractive index lower than that of the reflective layer 44.

  Since such a reflection suppressing layer 45 is provided, it can be suppressed that the laser light incident from the through hole 5 is reflected by the main surface 441 of the reflecting layer 44 and becomes return light, and the luminous efficiency. Can be increased. In addition, the reflection suppression layer 45 may be provided only in the area | region which covers the through-hole 5 in the main surface 441 of the reflection layer 44, and may be provided only in the area | region where a laser beam is irradiated.

[Modification 3]
Next, Modification 3 according to the present embodiment will be described.

  FIG. 6 is a cross-sectional view illustrating a schematic configuration of a light emitting element 4C according to the third modification, and specifically corresponds to FIG.

  As shown in FIG. 6, in the light emitting element 4C of the third modification, the phosphor particles 431 are arranged on the substrate 41 side in the phosphor layer 43c. The phosphor layer 43c has a two-layer structure. For example, an inorganic binder 435 containing a large number of phosphor particles 431 is laminated on a first layer 433 made of a transparent plate material such as glass. Two layers 434 are formed. The second layer 434 is disposed on the substrate 41 side, and the first layer 433 is disposed on the side opposite to the substrate 41, whereby the phosphor particles 431 are disposed on the substrate 41 side in the phosphor layer 43c.

  As described above, since the phosphor particles 431 are arranged so as to be biased toward the substrate 41 in the phosphor layer 43c, the interval between any phosphor particles 431 and the substrate 41 can be reduced. For this reason, heat can be efficiently transferred to the substrate 41 side.

  Further, since the phosphor layer 43c has a two-layer structure, the second layer 434 containing the phosphor particles 431 can be protected by the first layer 433.

  Even when the phosphor layer 43c is not formed in a two-layer structure, when forming the phosphor layer, the phosphor particles are aggregated on one main surface side of the phosphor layer so that the main surface is on the substrate 41 side. You may arrange.

[Modification 4]
Next, Modification 4 according to the present embodiment will be described.

  FIG. 7 is a cross-sectional view illustrating a schematic configuration of a light-emitting element 4D according to Modification Example 4, and specifically corresponds to FIG.

  In the above embodiment, the case where the bonding portion 42 includes the first electrode layer 421, the second electrode layer 422, and the metal bonding layer 423 has been described as an example. In the light emitting element 4D according to the fourth modification, a bonding portion 42d is formed by sintered silver nanoparticles.

  As shown in FIG. 5, the joint 42 d is interposed between the phosphor layer 43 and the substrate 41. As described above, since the bonding portion 42d is formed by sintering silver nanoparticles, metal bonding can be performed without the first electrode layer 421 and the second electrode layer 422. Moreover, since the reflectance is raised by sintering silver nanoparticle, it can function also as a reflection layer.

[Other embodiments]
As mentioned above, although the illuminating device which concerns on this invention was demonstrated based on the said embodiment and the modifications 1-4, this invention is not limited to said embodiment and each modification.

  In the said embodiment and each modification, although the case where the light emitting element 4 was applied to the illuminating device 1 was illustrated and demonstrated, the light emitting element 4 can also be used for another illumination system. Examples of other illumination systems include a projector and an in-vehicle headlight. When applied to a projector, the light emitting element 4 is used as a phosphor wheel.

  Further, a reflection suppressing layer such as an AR coating layer may be laminated on the surface of the phosphor layer 43 opposite to the main surface 432, that is, the light emitting side surface. Thereby, the light extraction efficiency can be increased.

  Other forms realized by various modifications conceived by those skilled in the art for the embodiments, and any combination of the components and functions in the embodiments and each modification without departing from the spirit of the present invention. Forms to be made are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Light source part 4,4A, 4B, 4C, 4D Light emitting element 5 Through-hole 41 Board | substrate 42,42d Joint part 43,43c Phosphor layer 44 Reflective layer 45 Antireflection layer 411 Main surface 421 1st electrode layer 422 1st Two-electrode layer 423 Metal bonding layer 431 Phosphor particles (phosphor)

Claims (7)

A phosphor layer comprising at least one phosphor;
A substrate having a higher thermal conductivity than the phosphor layer, the phosphor layer being disposed on one main surface side;
A bonding portion that is interposed between the phosphor layer and the substrate and metal-bonds the phosphor layer and the substrate;
In the substrate and the joint portion, a through hole is formed which is continuous in a direction intersecting the main surface of the substrate,
The through-hole is a light path of excitation light incident from the substrate side for exciting the phosphor. The reflective layer that transmits the excitation light and reflects the light emitted from the phosphor is laminated on the main surface of the phosphor layer on the substrate side so as to cover the through hole. 2. The light emitting device according to 1. A reflection suppression layer that transmits the excitation light and suppresses reflection of the transmitted excitation light from being reflected by the reflection layer covers the through hole on the main surface of the reflection layer on the substrate side. The light emitting device according to claim 1, wherein the light emitting device is laminated. The joint is
A first electrode layer laminated on the main surface of the substrate;
A second electrode layer laminated on the main surface of the phosphor layer on the substrate side;
The metal joining layer which is interposed between the 1st electrode layer and the 2nd electrode layer, and joins the 1st electrode layer and the 2nd electrode layer, It has any 1 paragraph of Claims 1-3. The light emitting element as described in. The light emitting device according to any one of claims 1 to 3, wherein the joint portion is made of sintered silver nanoparticles. The light emitting device according to claim 1, wherein the phosphor is disposed on the substrate side in the phosphor layer. The light emitting device according to any one of claims 1 to 6,
A light source unit that emits excitation light for exciting the phosphor of the light emitting element.

Images