JP2014033113A - Light-emitting device and light-emitting module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device and a light-emitting module which have high efficiency and high reliability.SOLUTION: A light-emitting device 10 includes: a light-emitting element (LED) 15 which emits light by energization; a transparent substrate 11 which is provided with a transparent electrode 14 having permeability to light outputted from the light-emitting element (LED) 15 and supplying power to the light-emitting element (LED) 15 and has permeability to light outputted from the light-emitting element (LED) 15 and on which the light-emitting element (LED) 15 is loaded; and a light guide member 12 which has permeability to light outputted from the light-emitting element (LED) 15 and is provided on that side of the transparent substrate 11 on which the light-emitting element (LED) 15 is loaded.

Description

  The present invention relates to a light emitting device and a light emitting module using a light emitting element.

  In recent years, the adoption of white LEDs (LEDs) for backlights and general lighting in mobile phone liquid crystal displays has dramatically increased the production volume of white LEDs and white LED packages equipped with them. Yes. The white LED package is a light emitting device including a semiconductor light emitting element (LED) configured to emit white light, and for example, a lead frame inside a recess of a resin case having a recess constituting a reflective surface. A sealing resin in which a phosphor is contained in the recess so as to cover the semiconductor light-emitting element by attaching the semiconductor light-emitting element to a lead frame exposed inside the recess and electrically connecting them. Is formed. Due to the increasing social needs for energy saving, higher efficiency of white LEDs is desired in the future.

  In the conventional package, BT resin, ceramic, a composite material of metal and resin, or the like is used as a substrate material on which the LED element is mounted. Reliability can be improved by using a substrate material having excellent heat resistance. However, when a substrate made of these materials is used for illumination, it is difficult to form illumination that efficiently irradiates light in the direction in which it is desired to irradiate, while the conventional package has light emission absorption of the LED on the reflection surface.

  Patent Document 1 discloses a visible light emitting diode chip, a transparent substrate on which the visible light emitting diode chip is mounted, a transparent electrode provided on the transparent substrate and supplying power to the visible light emitting diode chip, and a mounting surface side of the transparent substrate. There is disclosed a light source device comprising a light reflecting plate arranged oppositely and reflecting the light of a visible light emitting diode chip, and a light source device having electrodes formed of a transparent conductive material on a transparent substrate is publicly known. It is. However, there is room for improvement in the in-plane light emission distribution as the surface light source device. In addition, specific embodiments, such as the material of the member, are not described, and in order to realize a highly reliable light source that can withstand quality and practicality in terms of cost and reliability. More detailed examination is required.

JP-A-11-162233

  The present invention has been made in view of such problems, and an object thereof is to provide a light-emitting device and a light-emitting module with high efficiency and high reliability.

  For this purpose, a light-emitting device of the present invention includes a light-emitting element that emits light when energized, and a light-transmitting electrode that is transmissive to light output from the light-emitting element and supplies power to the light-emitting element. The light-transmitting substrate has a light-transmitting property, has a light-transmitting substrate on which the light-emitting device is mounted, and has a light-transmitting property with respect to the light output from the light-emitting device. And a translucent member provided on the side on which the element is stacked.

Here, the translucent substrate may include at least one resin component selected from the group consisting of an allyl ester resin, an epoxy resin, and an epoxy acrylate resin.
The translucent member may include at least one resin component selected from the group consisting of allyl ester resins, epoxy resins, and epoxy acrylate resins.
Furthermore, the translucent electrode may be at least one selected from the group consisting of ITO, IZO, IGO, zinc oxide, tin oxide, and silver nanowires.
Furthermore, the light-emitting element includes acrylic urethane resin, fluorine resin, acrylic silicone resin, urethane resin, acrylic resin, epoxy resin, polyester resin, alkyd resin, melamine resin, urea resin, guanamine resin, polyvinyl chloride, polyvinyl acetate. And a sealing material containing at least one resin component selected from vinyl butyral resin, styrene-butadiene resin, unsaturated polyester resin, silicone resin and allyl ester resin.
In addition, the sealing material may include a phosphor.
Furthermore, the translucent substrate and the translucent member may be made of the same material.
Furthermore, the thickness of the translucent substrate may be in the range of 50 μm to 1 mm.
The translucent member may have a thickness in the range of 100 μm to 1 mm.
The translucent substrate further includes a metal electrode mounted on the translucent electrode, and the light emitting element is connected to the metal electrode through a metal bump made of metal. It can be.

  Further, when the present invention is regarded as a light emitting module, the light emitting module according to the present invention is characterized in that a reflection film for controlling reflection of light output from the light emitting device is provided outside the light emitting device. .

  According to the present invention, a highly efficient and highly reliable light emitting device and light emitting module can be provided.

It is a schematic plan view which shows the light-emitting device to which 1st embodiment is applied. It is II-II sectional drawing of FIG. 1, and is a schematic sectional drawing of the light-emitting device of 1st embodiment. It is a schematic sectional drawing of the light emitting element (LED) to which 1st embodiment is applied. It is a figure which shows an example of the light emitting module to which the light-emitting device of 1st embodiment is applied. It is a schematic plan view which shows the light-emitting device to which 2nd embodiment is applied. It is VI-VI sectional drawing of FIG. 5, and is a schematic sectional drawing of the light-emitting device of 2nd embodiment. It is a schematic sectional drawing of the light emitting element (LED) to which 2nd embodiment is applied. It is a schematic plan view of a conventional (comparative example) light emitting device.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The present invention is not limited to these embodiments.
<First embodiment>
FIG. 1 is a schematic plan view showing a light emitting device 10 to which the first embodiment of the present invention is applied. 2 is a cross-sectional view taken along the line II-II in FIG. 1, and is a schematic cross-sectional view of the light emitting device 10 to which the first embodiment is applied.
As shown in FIG. 1 and FIG. 2, the light emitting device 10 of the first embodiment includes a light emitting diode (LED) 15 that emits light when energized and a light transmitting element on which the light emitting element (LED) 15 is mounted. A transparent substrate 11 as an example of a conductive substrate, and a light guide as an example of a translucent member provided to surround the outer periphery of the light emitting element (LED) 15 on the side of the transparent substrate 11 on which the light emitting element (LED) 15 is mounted. And a member 12. A translucent member is a member which can permeate | transmit the light emission from a light emitting element, and contains the light guide member and sealing material which are demonstrated below.

  In addition, the light emitting device 10 is laminated on the transparent lead 14 and the transparent lead 14 as an example of a translucent electrode that is provided between the transparent substrate 11 and the light guide member 12 and supplies power to the light emitting element (LED) 15. A low-resistance lead 13 as an example of a metal electrode having a lower resistivity than the transparent lead 14, and a sealing resin 16 as an example of a sealing material that is stacked on the transparent substrate 11 and seals the light emitting element (LED) 15. It has.

In the light emitting device 10 of the present embodiment, two light emitting circuits 17 a and 17 b in which two light emitting elements (LEDs) 15 are connected in series by a low resistance lead 13 and a transparent lead 14 are parallel on the transparent substrate 11. Are lined up.
Thus, in the light emitting device 10 of the present embodiment, four light emitting elements (LEDs) 15 are formed on the transparent substrate 11.

Then, each structural member of the light-emitting device 10 is demonstrated in order.
[Transparent substrate 11]
The transparent substrate 11 is composed of a plate-like member, and has a front surface on which a plurality (four in this example) of light emitting elements (LEDs) 15 are stacked, and a rear surface opposite to the front surface. The transparent substrate 11 has a rectangular shape when viewed from a direction perpendicular to the front surface or the back surface, as shown in FIG.
As described above, the light guide member 12, the transparent lead 14, and the low resistance lead 13 are provided on the surface side of the transparent substrate 11.

  The transparent substrate 11 is composed of a member having transparency to the light output from the light emitting element (LED) 15. In particular, the transparent substrate 11 preferably has transparency to visible light. In this case, the visible light transmittance in the transparent substrate 11 is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more.

The transparent substrate 11 of the present embodiment is composed of a resin film having a thickness of 500 μm. As the transparent substrate 11, it is preferable to use a long resin film that can be produced by a roll-to-roll method from the viewpoint of productivity.
The thickness of the transparent substrate 11 is preferably in the range of 50 μm to 1 mm. When the thickness of the transparent substrate 11 is excessively thinner than 50 μm, the rigidity is insufficient, and when the thickness is excessively thicker than 1 mm, the flexibility is insufficient, so that the transparent substrate 11 is difficult to handle. There is a case. A more preferable thickness of the transparent substrate 11 is in the range of 100 μm to 800 μm.
Note that, by setting the transparent substrate 11 to such a thickness, the light-emitting device 10 can be used while being curved in the thickness direction.

In the surface of the transparent substrate 11, a concave portion that is recessed from the front surface toward the back surface side may be formed in a region where the light emitting element (LED) 15 is mounted.
In the case where such a concave portion is formed on the surface of the transparent substrate 11, the concave portion can be formed by molding using a mold, for example, but can also be punched out by a router. When the recess is formed by router processing, fine unevenness can be formed on the surface of the recess, and the light output from the light emitting element (LED) 15 can be scattered by the unevenness. Thereby, compared with the case where this structure is not employ | adopted, in the light-emitting device 10, it becomes possible to improve the extraction efficiency of light. Furthermore, due to the anchor effect due to the unevenness, the adhesion between the sealing resin 16 injected into the later-described through recess 12a and the transparent substrate 11 is also improved.

[Light guide member 12]
The light guide member 12 is composed of a plate-like member similarly to the transparent substrate 11, and is provided on the surface side of the transparent substrate 11 as shown in FIGS. 1 and 2. In the following description, the surface of the light guide member 12 that faces the transparent substrate 11 is referred to as a back surface, and the surface opposite to the back surface is referred to as a front surface. In the present embodiment, the light guide member 12 is bonded to the surface of the transparent substrate 11 via a highly transparent adhesive transfer tape [OCA tape] (Optical Clear Adhesive Tape) or an ultraviolet curable adhesive. Yes.
As shown in FIG. 1, the light guide member 12 has a rectangular shape when viewed from the direction perpendicular to the front surface or the back surface. In the present embodiment, when viewed from the surface side of the light guide member 12, the area of the light guide member 12 is smaller than the area of the transparent substrate 11, and the periphery of the transparent substrate 11 is exposed to the outside.

  The thickness of the light guide member 12 is set in consideration of mounting of the light emitting element (LED) 15. That is, in the light emitting device 10 according to the present embodiment, as shown in FIG. 2, the light emitting elements (LEDs) 15 stacked on the surface of the transparent substrate 11 are provided so as not to protrude from the surface of the light guide member 12. . Therefore, the thickness of the light guide member 12 is preferably thicker than the height of the light emitting element (LED) 15, for example, in the range of 100 μm to 1 mm.

Further, as shown in FIGS. 1 and 2, the light guide member 12 has a plurality (four in this example) of through recesses 12 a penetrating from the front surface toward the back surface. The through recess 12 a has a tapered wall surface whose diameter gradually decreases from the front surface side to the back surface side of the light guide member 12.
In the light emitting device 10 according to the present embodiment, the plurality of light emitting elements (LEDs) 15 stacked on the surface of the transparent substrate 11 are positioned inside the through recesses 12 a provided in the light guide member 12. Is provided.

  The through recess 12a can be formed by laser processing or NC (Numerical Control) router (grinding with a grindstone) processing. When the through recess 12a is formed by NC router processing, the light output from the light emitting element (LED) 15 disposed inside the through recess 12a is scattered by the fine unevenness formed on the inner peripheral surface of the through recess 12a. Thus, the light extraction effect in the light emitting device 10 can be further improved. Further, by forming irregularities on the inner peripheral surface of the through recess 12a, the adhesion between the sealing resin 16 injected into the through recess 12a and the light guide member 12 can be improved due to the anchor effect due to the irregularities. . The roughness Rz (maximum surface roughness) varies depending on the thickness of the light guide member 12, the diameter of the through recess 12a, and the like, but for example, a range of 1 μm to 100 μm is preferable, and a range of 5 μm to 30 μm is more preferable. .

Similar to the transparent substrate 11, the light guide member 12 is formed of a member having transparency to the light output from the light emitting element (LED) 15. Similar to the transparent substrate 11, the light guide member 12 preferably has transparency to visible light. In this case, the visible light transmittance of the light guide member 12 is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more.
Furthermore, the light guide member 12 is preferably made of a material having high heat resistance. Specifically, a material that can withstand a process at 250 ° C. or higher for 10 minutes or longer is preferable. The linear expansion coefficient of the light guide member 12 is within ± 20%, preferably within ± 10% with respect to the transparent substrate 11.

[Material of transparent substrate 11 and light guide member 12]
As a material which comprises the said transparent substrate 11 and the light guide member 12, what has the transmittance | permeability with respect to the light output from the light emitting element (LED) 15 is used as mentioned above. From the viewpoint of reliability characteristics, it is preferable to use a resin that absorbs less light in a short wavelength region of 400 nm or less.
In the manufacturing process of the light emitting device 10, heating is necessary when the light emitting element (LED) 15 is mounted on the transparent substrate 11. Specifically, when the light emitting element (LED) 15 is connected to the transparent substrate 11 via metal bumps, the heating is about 300 ° C., and when the light emitting element (LED) 15 is connected via silver paste, the heating is about 150 ° C. to 200 ° C. is necessary. Furthermore, in the manufacturing process of the light emitting device 10, in addition to the mounting process of the light emitting element (LED) 15 described above, a plurality of processes may be performed under high temperature conditions such as solder reflow.
From the above, as a material used for the transparent substrate 11 and the light guide member 12, it is preferable to use a resin that can withstand a high temperature of 150 ° C. or higher, preferably 200 ° C. or higher, and further about 250 ° C.

  Examples of the resin used as the transparent substrate 11 and the light guide member 12 include cycloolefin [Zeonor, Zeonex (manufactured by ZEON Corporation), Arton (manufactured by JSR Corporation), adamantate (manufactured by Idemitsu Kosan Co., Ltd.), etc.] (COP), polyamide (PA), polyurethane (PU), polyethersulfone (PES), polyetheretherketone (PEEK), liquid crystal polymer (LCP), allyl ester resin, epoxy resin, epoxy acrylate resin, and the like.

Among these, allyl ester resins and epoxy resins are particularly preferable because they have a high total light transmittance and can produce an efficient light-emitting device 10.
From the viewpoint of heat resistance, it is preferable to use an allyl ester resin. By using a resin film having high heat resistance, the light emitting device 10 can achieve high efficiency and high reliability.

Further, by forming the transparent substrate 11 and the light guide member 12 with the above-described flexible resin, the light emitting device 10 is deformed (curved) in the thickness direction of the transparent substrate 11 and the light guide member 12. ) Can be used.
Furthermore, it is preferable to use the same resin as the transparent substrate 11 and the light guide member 12. Thereby, generation | occurrence | production of curvature etc. can be suppressed in the transparent substrate 11 and the light guide member 12, and the light-emitting device 10 with higher reliability is obtained.

The transparent substrate 11 and the light guide member 12 are joined with a highly transparent adhesive transfer tape [OCA tape] (Optical Clear Adhesive Tape) or an ultraviolet curable adhesive. In particular, it is preferable to use an OCA tape for joining the light guide member 12 and the transparent substrate 11.
Moreover, when forming the transparent substrate 11 and the light guide member 12 from the same material, you may comprise the transparent substrate 11 and the light guide member 12 integrally. By integrally configuring the transparent substrate 11 and the light guide member 12, light refraction at the interface between the transparent substrate 11 and the light guide member 12 can be suppressed, and light emission can be achieved compared to the case where this configuration is not employed. The apparatus 10 can suppress a decrease in light extraction efficiency.

[Transparent lead 14]
As described above, the transparent lead 14 is provided between the front surface of the transparent substrate 11 and the back surface of the light guide member 12.
As described above, the light emitting device 10 according to the present embodiment has the two light emitting circuits 17 a and 17 b arranged on the transparent substrate 11. Each of the light emitting circuits 17 a and 17 b has a structure in which two light emitting elements (LEDs) 15 are connected in series by a transparent lead 14 and a low resistance lead 13. That is, the light emitting circuits 17a and 17b have the same configuration. Therefore, in the following description, the configuration of the transparent lead 14 will be described by taking the light emitting circuit 17a as an example.

In the light emitting circuit 17a, a plurality of transparent leads 14 are provided on the surface of the transparent substrate 11, as shown in FIGS.
Specifically, as shown in FIG. 2, the transparent lead 14 is connected to one (right side in FIG. 2) light emitting element (LED) 15 of the light emitting circuit 17a from one end (right side in FIG. 2) of the transparent substrate 11. The first lead portion 14a extending to the lower side of the N-type bonding electrode 26 (see FIG. 3 described later) and the transparent substrate from the lower side of the P-type bonding electrode 27 (see FIG. 3 described later) of the one light emitting element (LED) 15 A second lead portion 14b extending to the central portion of the transparent substrate 11, and a third lead portion extending from the central portion of the transparent substrate 11 to below the N-type bonding electrode 26 in the other light emitting element (LED) 15 in the light emitting circuit 17a (left side in FIG. 2) The other side of the transparent substrate 11 (the left side in FIG. 2) from below the lead portion 14c and the P-type bonding electrode 27 in the other light emitting element (LED) 15. And a fourth lead portion 14d that extends to the end.
In the light emitting device 10 of the present embodiment, the first lead portion 14a to the fourth lead portion 14d are provided separately from each other.

The transparent lead 14 is made of a conductive material. The resistivity of the transparent lead 14 is preferably 10 ⁻⁴ Ω · cm or more and 10 ⁻³ Ω · cm or less.
The transparent lead 14 is made of a material having transparency to light output from the light emitting element (LED) 15. The transparent lead 14 preferably has a visible light transmittance, and in this case, the visible light transmittance of the transparent lead 14 is preferably 80% or more.
As the material of the transparent lead 14, a metal oxide conductive film such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ZnO, or IGO (Indium Gallium Oxide) can be used. In addition, a silver filler and silver nanowire can also be used.
The pattern of the transparent lead 14 can be manufactured by various known methods such as a sputtering method, a vacuum deposition method, and pattern etching, or a combination of screen printing and baking of conductive ink.

[Low resistance lead 13]
As described above, the low resistance lead 13 is provided on the transparent lead 14 and supplies power to the light emitting element (LED) 15 together with the transparent lead 14. Similar to the description of the transparent lead 14 described above, here, the configuration of the low resistance lead 13 in the light emitting circuit 17a will be described.

In the light emitting circuit 17a, a plurality of low resistance leads 13 are provided on the transparent lead 14, as shown in FIGS.
Specifically, the low resistance lead 13 is provided on one end (right side in FIG. 2) of the transparent substrate 11 on the first lead portion 14 a of the transparent lead 14, and a part of the light guide member 12. The first external connection portion 13a exposed to the outside from the outer periphery and the fourth lead portion 14d are provided at the other end (left side in FIG. 2) of the transparent substrate 11, and a part of the outer periphery of the light guide member 12 And a second external connection portion 13b exposed to the outside.
The low-resistance lead 13 is provided on the first lead portion 14a of the transparent lead 14, and is connected to the N-type bonding electrode 26 (see FIG. 3) of one light emitting element (LED) 15 (right side in FIG. 2). The first cathode connection portion 13c and the first cathode connection portion 13d provided on the second lead portion 14b and to which the P-type bonding electrode 27 (see FIG. 3) of one light emitting element (LED) 15 is connected. A second anode connection portion 13e provided on the third lead portion 14c and connected to the N-type bonding electrode 26 of the other light emitting element (LED) 15 (left side in FIG. 2), and a fourth lead portion 14d. And a second cathode connecting portion 13f provided on the other side to which the P-type bonding electrode 27 of the other light emitting element (LED) 15 is connected.
Further, the low resistance lead 13 is provided across the second lead portion 14b and the third lead portion 14c of the transparent lead 14, and electrically connects the second lead portion 14b and the third lead portion 14c. It has a connection part 13g.

The first external connection portion 13 a and the second external connection portion 13 b of the low-resistance lead 13 are partly held between the transparent substrate 11 and the light guide member 12, and part of the light guide member 12. It is exposed to the outside from the outer periphery. And the 1st external connection part 13a and the 2nd external connection part 13b are a terminal for receiving electric power from the exterior of the light-emitting device 10. FIG.
The first anode connection portion 13c, the first cathode connection portion 13d, the second anode connection portion 13e, and the second cathode connection portion 13f of the low-resistance lead 13 are partially part of the transparent substrate 11 and the light guide member. 12, and a part thereof is exposed through the through recess 12 a, and each serves as a terminal for supplying power to the light emitting element (LED) 15.
The lead connection portion 13g of the low resistance lead 13 is held between the transparent substrate 11, the second lead portion 14b, the third lead portion 14c, and the light guide member 12. The lead connection portion 13g is provided to reduce the electrical resistance when a current flows from one light emitting element (LED) 15 side to the other light emitting element (LED) 15 side.

The low resistance lead 13 is a metal sheet having a thickness of about 0.01 mm to 0.5 mm. As an example, the low resistance lead 13 is based on a metal conductor such as a copper alloy, and a silver plating layer is formed by silver plating on the surface thereof. Is formed. Therefore, the first anode connection portion 13c, which is a metal conductor, is connected to the surface of the transparent substrate 11 exposed from the through recess 12a of the light guide member 12 before the sealing resin 16 is injected. The silver plating layers of the portion 13d, the second anode connection portion 13e, and the second cathode connection portion 13f are partially exposed. However, a part of the first anode connecting portion 13c, the first cathode connecting portion 13d, the second anode connecting portion 13e, and the second cathode connecting portion 13f is covered with the light guide member 12, and the metal surface. It is possible to prevent the deterioration of the low resistance lead 13 due to the corrosion due to the exposure.
The low resistance lead 13 made of a metal sheet obtained by silver plating on a metal conductor can be formed by a known method.

  In addition to the above-described metal sheet, the low-resistance lead 13 may be formed, for example, by printing conductive ink in which metal fillers (particles, fibers, wires, etc.) are dispersed on the designed electrodes and wiring patterns. . In this case, it is preferable to use a thermosetting or ultraviolet curable ink as the conductive ink. When the thermosetting conductive ink is used, it is preferable to use a transparent substrate 11 having a high heat resistant temperature. Moreover, when using an ultraviolet curable type | mold, hardening progresses and a low-resistance metal film with a sufficient quality can be formed by using a resin film having a high transmittance to ultraviolet light. Also in this case, since the ultraviolet light irradiation surface becomes high temperature, it is preferable to use the transparent substrate 11 having heat resistance of 150 ° C. or higher, preferably 200 ° C. or higher, and further 250 ° C. or higher. The term “having heat resistance” as used herein means that the dimensional change rate when heat-treated for 1 hour at a temperature of 150 ° C. is 0.5% or less, and light when heat-treated for 20 minutes in air at 250 ° C. It means that the decrease in transmittance is 2% or less. With this characteristic, mounting using solder reflow is possible, and deterioration of optical characteristics required for a light emitting device of an LED can be suppressed.

  In addition to the above-described method, the low-resistance lead 13 may be formed by, for example, a plating method, a metal foil bonding method, a sputtering method, a vacuum deposition method, etc., and a pattern etching, or by joining a pre-patterned lead frame. Can be formed.

  Since the low resistance lead 13 is composed of a metal sheet or the like as described above, the transmittance of light output from the light emitting element (LED) 15 is lower than that of the transparent lead 14 or the like (transmits light). Hard to do). Therefore, in order to suppress a decrease in light extraction efficiency in the light emitting device 10, it is preferable that the area where the low resistance lead 13 is formed is small.

[Light emitting element 15]
FIG. 3 is a schematic cross-sectional view of the LED 15 that is a light-emitting element to which the present exemplary embodiment is applied.
The light emitting element (LED) 15 of the present embodiment is composed of a compound semiconductor. The compound semiconductor constituting the light emitting element (LED) 15 is not particularly limited. Further, an organic EL element may be used as the light emitting element 15.
In the light emitting device 10 of the present embodiment, when white light is emitted in combination with a phosphor, the light emitting element (LED) 15 has a structure that emits blue light having a main light emission peak in a wavelength region of 350 nm to 500 nm. It is preferable to adopt.
In the case where the light emitting device 10 emits monochromatic light, the light emitting element (LED) 15 is not limited to emitting blue light, and the light emitting element (LED) 15 has any wavelength region from ultraviolet to infrared. Any known structure having a main emission peak can be used.
In the light emitting device 10 of the present embodiment, a light emitting element (LED) 15 having a group III nitride semiconductor is used. In addition, the light emitting element (LED) 15 of this Embodiment outputs blue light.

The light-emitting element (LED) 15 of the present embodiment includes a substrate 20, an N-type layer 21 laminated on the substrate 20, a light-emitting layer 22 laminated on the N-type layer 21, and a laminate on the light-emitting layer 22. P-type layer 23, N-type ohmic electrode 24 connected to N-type layer 21, P-type transparent electrode 25 stacked on P-type layer 23, and N-type connected to N-type ohmic electrode 24 A bonding electrode 26 and a P-type bonding electrode 27 connected to the P-type transparent electrode 25 are provided. In the following description, the N-type layer 21, the light emitting layer 22, and the P-type layer 23 may be collectively referred to as a laminated semiconductor layer.
Further, when the light emitting element (LED) 15 is mounted on the light emitting device 10, bumps 28 provided on the N-type bonding electrode 26 and the P-type bonding electrode 27 are formed. The light emitting element (LED) 15 is connected to the low resistance lead 13 provided on the transparent lead 14 and exposed through the through recess 12 a of the light guide member 12 via the bump 28 and mounted on the transparent substrate 11. (See also FIGS. 1 and 2).

The substrate 20 is made of a member that is transparent to the light emitted from the light emitting layer 22, and for example, a sapphire substrate, a transparent body such as glass, or a compound semiconductor such as GaP or GaAs can be used.
As the laminated semiconductor layer (N-type layer 21, light emitting layer 22, and P-type layer 23) laminated on the substrate 20, for example, a layer made of a group III nitride semiconductor mainly composed of GaN can be used. The laminated semiconductor layer can be formed on the substrate 20 by epitaxial growth using a vapor phase method or a liquid phase method.
Note that a seed layer made of, for example, AlN or a base layer made of GaN formed on the seed layer may be provided between the substrate 20 and the N-type layer 21.

The P-type transparent electrode 25 and the N-type ohmic electrode 24 are provided to efficiently inject current into the laminated semiconductor layer of the light emitting element (LED) 15.
The P-type transparent electrode 25 is made of a material having transparency to the light output from the light emitting layer 22. By using the P-type transparent electrode 25 as a transparent electrode, the light extraction efficiency can be increased. As a material constituting the P-type transparent electrode 25, for example, an oxide semiconductor such as ITO, IZO, or IGO is suitable.
Further, as the N-type ohmic electrode 24, it is preferable to use a metal having low contact resistance with the N-type layer 21. For example, a single substance such as Al, Ti, W, Ni, Cr, V, or an alloy thereof is used. be able to.

  The N-type bonding electrode 26 and the P-type bonding electrode 27 are formed on the N-type ohmic electrode 24 and the P-type transparent electrode 25, respectively, so that electrical wiring to the light emitting element (LED) 15 is facilitated. As the N-type bonding electrode 26 and the P-type bonding electrode 27, for example, gold or aluminum is used.

The bump 28 connects the N-type bonding electrode 26 and the first anode connecting portion 13c or the second anode connecting portion 13e of the low resistance lead 13 when the light emitting element (LED) 15 is mounted on the transparent substrate 11. The P-type bonding electrode 27 is used to connect the first cathode connecting portion 13d or the second cathode connecting portion 13f.
The height of the bump 28 is set to an appropriate range in which the stress generated due to the difference in thermal expansion between the transparent substrate 11 and the light emitting element (LED) 15 can be relaxed. The height of the bump 28 is preferably 10 μm or more, more preferably 20 μm or more. The higher the height of the bump 28 is, the more advantageous in terms of stress relaxation. However, if the height of the bump 28 is excessively large, a problem arises in stability when the light emitting element (LED) 15 is mounted. , 50 μm or less, and more preferably 30 μm or less. That is, the height of the bump 28 is preferably in the range of 10 μm to 50 μm, and more preferably in the range of 20 μm to 30 μm.

  The material of the bump 28 is preferably Au because it has a low resistivity and is chemically stable. However, the material of the bump 28 is not limited to Au, and for example, a low resistivity metal such as Cu, Al, or Ag can be used. It is also possible to form the bumps 28 with solder containing low melting point In, Sn, Zn, Pd. Furthermore, it is possible to form a eutectic electrode having a lower melting point on the bump 28.

The light emitting element (LED) 15 of this embodiment is flip-chip (face-down) mounted on the low resistance lead 13 provided on the transparent substrate 11 via the bump 28. Thereby, compared with the case where the light emitting element (LED) 15 is connected to the low resistance lead 13 by wire bonding, for example, light extraction is improved and the light emission efficiency is improved. When the light emitting element (LED) 15 is connected by wire bonding to the low resistance lead 13 or the like, disconnection may occur due to stress due to thermal contraction of the transparent substrate 11 or the like. Therefore, the flip-chip mounting of the light emitting element (LED) 15 as in the present embodiment reduces the reliability of the light emitting device 10 compared to the case where the light emitting element (LED) 15 is connected by wire bonding. Can be suppressed.
As a method for mounting the light emitting element (LED) 15 on the low resistance lead 13 via the bump 28, for example, a stud bump method, a plating bump method, or the like can be used.

When the light emitting element (LED) 15 is flip-chip mounted, the P-type electrode is generally a reflective electrode using aluminum, silver, an aluminum alloy or a silver alloy having a high light reflectance. However, by using a structure having a P-type transparent electrode 25 that is a transparent electrode without using a reflective electrode, like the light-emitting element (LED) 15 of the present embodiment, the bottom surface direction of the light-emitting element (LED) 15 ( Light can be effectively extracted also on the side opposite to the substrate 20.
In the present invention, the case where the light emitting element (LED) is mounted by wire bonding is not excluded. The effect of improving the light emission efficiency can also be obtained when wire bonding is implemented.

[Sealing resin 16]
As shown in FIG. 2, the sealing resin 16 is provided so as to fill the through recess 12 a formed in the light guide member 12 in order to seal the light emitting element (LED) 15 stacked on the transparent substrate 11. It is done.
When the light emitting device 10 emits white light by combining the light emitting element (LED) 15 and the phosphor, the sealing resin 16 absorbs light emitted from the light emitting element (LED) 15 and emits light having a longer wavelength. Made of a transparent resin in which a phosphor (hereinafter also referred to as phosphor powder) is uniformly dispersed.
As an example, the sealing resin 16 absorbs blue light emitted from the light emitting element (LED) 15 and emits green light, and absorbs blue light emitted from the light emitting element (LED) 15 and emits red light. The case where it contains red fluorescent substance is mentioned. Note that the red phosphor is also excited by the light emitted by the green phosphor, so the chromaticity of the light emitted from the light emitting device 10 changes depending on the ratio of the green and red phosphors. For adjusting the chromaticity, the emission wavelength of the light emitting element (LED) 15, the ratio of the green and red phosphors, the concentration of the phosphor in the sealing resin 16, and the upper surface where the sealing resin 16 is embedded, that is, The shape of the emission surface from which light is emitted is related.

  In the light emitting device 10, blue light emitted from the light emitting element (LED) 15, green light emitted from the green phosphor contained in the phosphor powder, and red light emitted from the red phosphor contained in the phosphor powder. The three primary colors of blue, green, and red are aligned. For this reason, white light in which the three primary colors are mixed is emitted from the emission surface of the sealing resin 16.

The green phosphor suitably used for the phosphor powder described above is preferably a silicate phosphor (BaSiO ₄ : Eu ²⁺ ), and the red phosphor is preferably a nitride phosphor (CaAlSiN ₃ : Eu ²⁺ ). Since these green phosphors and red phosphors have a relatively low true density of 3.5 to 4.7 g / cm ³ and an average particle diameter of about 10 μm in mass average can be produced, sealing is possible. An LED having good dispersibility and high luminous efficiency with respect to the stop resin can be produced.

Here, since the green phosphor (BaSiO ₄ : Eu ²⁺ ) has an excitation wavelength of 380 to 440 nm and an emission wavelength of 508 nm, the required characteristics for converting the blue light used in the present embodiment into green light are satisfied. As a result, both the excitation wavelength and the emission wavelength are too short. However, by replacing a part of Ba with other alkaline earth elements such as Sr, Ca, and Mg, the excitation wavelength and the emission wavelength can be moved to the longer wavelength side. As an example, by using (Ca, Sr, Ba) ₂ SiO ₄ : Eu ²⁺ , the excitation wavelength can be adjusted to 455 nm and the emission wavelength can be adjusted to 528 nm.

The red phosphor (CaAlSiN ₃ : Eu ²⁺ ) has an excitation wavelength of 400 to 500 nm and an emission wavelength of 640 nm.
The full width at half maximum of the peak wavelength of the light output from the light emitting element (LED) 15, the light output from the green phosphor, and the light output from the red phosphor varies depending on the purpose of use. For illumination purposes, it is preferable that the waveform of the peak wavelength is as broad as possible. However, in the backlight application of a liquid crystal display device, it is preferable to use a waveform having the sharpest possible waveform. In order to increase the color rendering properties (the degree that looks the same as the color seen under sunlight) for lighting purposes, it is preferable to align the wavelength distribution of sunlight as much as possible, and it is required that all wavelengths are included to the same extent. Is done. On the other hand, the color reproduction range when used for a backlight of a liquid crystal display device preferably has a wide area surrounded by three points on the chromaticity coordinates of blue, green, and red. That is, it is important that the color purity is as high as possible. For this purpose, it is preferable to make the wavelength distribution of the three primary colors as sharp as possible.

  The case where the phosphor is used in combination with the light emitting element (LED) 15 has been described above. The light emitting element (LED) 15 that outputs each light of blue, green, and red is sealed with a transparent resin that does not contain the phosphor. It can also be. The light emitting device 10 can include one or a plurality of light emitting elements on the transparent substrate 11. In this case, white light can be emitted using a combination of individually sealed light emitting elements (LEDs) 15 that output blue, green, and red light, or blue, green, and red light emitting elements. It can also be set as the structure which mounts on the transparent substrate 11 in the state which (LED) 15 adjoined, and collectively seals these light emitting elements (LED) 15 with transparent resin.

As the transparent resin constituting the sealing resin 16, various resins that are transparent in the visible region can be applied as long as they have a performance for sealing the light emitting element (LED) 15. The transparent resin includes a curable resin and a curing agent as main components, and further includes a curing reaction accelerator, an antioxidant, a discoloration preventing agent, a photodegradation preventing agent, a reactive diluent, an inorganic filler, and a difficulty as necessary. It is preferable to use one containing a flame retardant, an organic solvent or the like.
Examples of the curable resin include a one-component or two-component curable resin containing a main agent, a curing agent, and a curing reaction accelerator that accelerates a curing reaction between the main agent and the curing agent. Specific examples include curable silicone resins, curable epoxy resins, curable epoxy silicone hybrid resins, and curable acrylic resins. Among these, a curable silicone resin and a curable epoxy resin are preferable.

(Curable silicone resin)
In general, the curable silicone resin includes a compound having a silicon atom and an alkenyl group in the molecule (main agent), a compound having a hydrogen atom bonded to the silicon atom in the molecule (curing agent), and a hydrosilylation reaction catalyst (curing). A liquid curable silicone resin containing a reaction accelerator) is preferred. Examples of the main agent include organopolysiloxane having preferably 2 to 6 alkenyl groups in one molecule. The silicon atom-bonded alkenyl group may be at the molecular chain terminal, at the molecular chain non-terminal, or both in the organopolysiloxane molecule. The structure of the organopolysiloxane is not particularly limited, and may be any of linear, branched, three-dimensional network, cyclic, etc., but is preferably a three-dimensional network.

  Examples of the curing agent include organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule. The hydrogen atom bonded to the silicon atom may be at the end of the molecular chain, at the non-terminal end of the molecular chain, or both in the organohydrogenpolysiloxane molecule. Further, the structure of the organohydrogenpolysiloxane is not particularly limited, and may be any of linear, branched, three-dimensional network, cyclic, etc., preferably linear or Annular.

  The curing reaction accelerator includes an alkenyl group bonded to a silicon atom in an organopolysiloxane as a main agent and a bond between a silicon atom and a hydrogen atom in an organohydrogenpolysiloxane as a curing agent, that is, an Si-H bond. Examples include hydrosilylation reaction catalysts that promote the hydrosilylation reaction. The hydrosilylation reaction catalyst is not particularly limited, and any conventionally known catalyst can be used. For example, platinum black, platinum chloride, chloroplatinic acid, reaction product of chloroplatinic acid and monohydric alcohol, complex of chloroplatinic acid and olefins, platinum-based catalyst such as platinum bisacetoacetate; palladium-based catalyst And platinum group metal catalysts such as rhodium catalysts.

(Curable epoxy resin)
As the main component of the curable epoxy resin, one having two or more epoxy groups in one molecule and liquid at room temperature (for example, 25 ° C.) is preferable. Specifically, bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin and hydrogenated bisphenol A; novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin; triphenolmethane type Triphenolalkane type epoxy resins such as epoxy resins and triphenolpropane type epoxy resins; phenol aralkyl type epoxy resins, biphenyl aralkyl type epoxy resins, stilbene type epoxy resins, naphthalene type epoxy resins, biphenyl type epoxy resins, cyclopentadiene type epoxy resins Etc. These curable epoxy resins can be used alone or in combination of two or more.

Examples of the curing agent for the curable epoxy resin include aliphatic polyamines such as diethylenetriamine (DETA) and triethylenetetramine (TETA); diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), diaminodiphenylsulfone (DDS), Aromatic polyamines such as metaxylylene diamine (MXDA); polyamine compounds including dicyandiamide (DICY), organic acid dihydrazide, etc .; alicyclic acids such as hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA) Anhydrides; acid anhydrides including aromatic acid anhydrides such as trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), benzophenone tetracarboxylic acid (BTDA); novolac-type phenolic resin, phenol polymer Polyphenol compounds such as polysulfides, thioesters, thioethers and other polymercaptan compounds; isocyanate compounds such as isocyanate prepolymers and blocked isocyanates; polyaddition type curing agents such as organic acids such as carboxylic acid-containing polyester resins; benzyldimethylamine (BDMA) ), Tertiary amine compounds such as 2,4,6-trisdimethylaminomethylphenol (DMP-30); imidazole compounds such as 2-methylimidazole and 2-ethyl-4-methylimidazole (EMI24); BF ₃ complex and the like Catalyst type curing agents such as Lewis acids; phenol resins such as resol type phenol resins; urea resins such as methylol group-containing urea resins; condensation type curing agents such as melamine resins such as methylol group-containing melamine resins It is done. These curing agents can be used alone or in combination of two or more. Although content of a hardening | curing agent is not specifically limited, Usually, 0.1 mass%-30 mass% of the whole liquid curable resin composition, Preferably, it is suitably selected in the range of 5 mass%-15 mass%.

  Examples of curing reaction accelerators for curable epoxy resins include organic phosphines such as imidazole compounds, amine compounds, triphenylphosphine, and methyldiphenylphosphine; tetraphenylphosphonium / tetraphenylborate, tetraphenylphosphonium / tetrabenzoate borate, Tetrasubstituted phosphonium / tetrasubstituted borates such as tetraphenylphosphonium / tetranaphthoic acid borate, tetraphenylphosphonium / tetranaphthyloxyborate, tetraphenylphosphonium / tetranaphthyloxyborate; adducts of phosphine compounds and quinone compounds It is done. Among these, an imidazole compound and an adduct of a phosphine compound and a quinone compound are preferable.

  Further, an exit surface for emitting light output from the light emitting element (LED) 15 is formed on the surface in which the sealing resin 16 is filled in the through recess 12 a of the light guide member 12. In the light emitting device 10, although not shown, it is preferable that the central portion of the emission surface is recessed from the upper surface of the light guide member 12 or has a convex shape. The displacement d is particularly preferably set in the range of −100 μm to +100 μm from the upper surface. The displacement amount d is a difference between the height of the end portion of the resin embedding part, that is, the surface of the light guide member 12 and the minimum height or the maximum height of the emission surface. Here, when the height of the surface of the light guide member 12 is defined as a reference (0), the side closer to the light emitting element (LED) 15 is minus (−), and the far side is plus (+).

  Therefore, the displacement d is in the range of −100 μm to +100 μm from the upper surface. When the height of the surface of the light guide member 12 is 0 μm, the recess is the surface of the light guide member 12 when the emission surface is recessed. Means that the projection height is 100 μm or less. This displacement d can be measured with a laser displacement meter (for example, ZSHLD2 manufactured by OMRON).

[Light emission operation]
Next, the light emission operation of the light emitting device 10 shown in FIG. 1 will be described.
When a current is passed to each light emitting element (LED) 15 through the low resistance lead 13 and the transparent lead 14 with the second external connection portion 13b of the low resistance lead 13 as a positive electrode and the first external connection portion 13a as a negative electrode, The light emitting element (LED) 15 emits blue light. The blue light emitted from the light emitting element (LED) 15 travels in the sealing resin 16 and is reflected directly or from the surface of the transparent substrate 11 or the wall surface of the through recess 12a in the light guide member 12 to the outside from the emission surface. Emitted. In addition, the light transmitted without being reflected by the wall surface of the through recess 12 a travels through the light guide member 12 and is then emitted to the outside of the light guide member 12.
Further, the light output from the light emitting element (LED) 15 toward the transparent substrate 11 is radiated to the outside directly or via the transparent lead 14.

That is, in the light emitting device 10 according to the present embodiment, the light output from the light emitting element (LED) 15 is extracted from a portion other than the low resistance lead 13 (the transparent substrate 11, the light guide member 12, and the sealing resin 16). Is possible. Thereby, the light-emitting device 10 of this Embodiment can extract light very efficiently compared with the case where this configuration is not adopted.
If it is this structure, it is possible to control the resistance value of an electrode according to the use conditions of the light-emitting device 10. FIG. In particular, when used in a low current region of 100 mA or less, it is not necessary to reduce the resistance value of the electrode so much, and the light emitting device 10 with high light emission (light extraction) efficiency can be obtained while maintaining the transmittance of the transparent lead 14. can get.

[Method for Manufacturing Light Emitting Device]
Then, the manufacturing method of the light-emitting device 10 is demonstrated, referring FIG.
First, a pattern of transparent leads 14 is formed on a transparent film that becomes the transparent substrate 11. As a material for the transparent lead 14, a metal oxide conductive film such as ITO, IZO, ZnO, or IGO can be used. In addition, a silver filler and silver nanowire can also be used. For the pattern formation of the transparent lead 14, a screen printing method or a photolithography method is suitable.
Subsequently, the low resistance lead 13 is formed in a corresponding region on the transparent lead 14 formed by such a method. The low-resistance lead 13 can be formed by sputtering of metal, pattern etching of a metal film after vacuum deposition, baking after screen printing of a conductive ink composition containing a metal filler (particles, wires), and the like.

  Next, on the first anode connecting portion 13c and the first cathode connecting portion 13d of the low resistance lead 13, and on the second anode connecting portion 13e and the second cathode connecting portion 13f, FIG. A light emitting element (LED) 15 shown in FIG. A flip chip bonder can be used to mount the light emitting element (LED) 15. Specifically, thermocompression bonding is performed while applying vibration by ultrasonic waves, and the first anode connecting portion 13 c (second anode connecting portion 13 e) of the transparent substrate 11 and the N-type bonding electrode 26 of the light emitting element (LED) 15. The bump 28 provided on the upper surface is connected, the first cathode connection portion 13d (second cathode connection portion 13f), and the bump 28 provided on the P-type bonding electrode 27 of the light emitting element (LED) 15 Connect.

  After the light emitting element (LED) 15 is mounted, an underfill agent may be injected into the gap between the light emitting element (LED) 15 and the transparent substrate 11 in order to stabilize the connection. In the present embodiment, as the underfill agent, it is preferable to use a transparent silicone resin or epoxy resin in order to transmit light output from the light emitting element (LED) 15 and traveling toward the transparent substrate 11 side.

Next, the light guide member 12 having the same number of through recesses 12a as the light emitting elements (LEDs) 15 mounted on the transparent substrate 11 is placed so that the light emitting elements (LEDs) 15 are located on the inner peripheral side of the through recesses 12a. Affixed on the transparent substrate 11.
As described above, the through recess 12a provided in the light guide member 12 is preferably formed by NC router processing, but may be formed by punching. Further, the light guide member 12 may be provided with a through-concave portion 12a by forming the light guide member 12 by a casting method using a mold.
For joining the light guide member 12 and the transparent substrate 11, it is preferable to use a highly transparent adhesive transfer tape [OCA tape] (Optical Clear Adhesive Tape), but it is also possible to join with an ultraviolet curing adhesive. It is.

Next, the sealing resin 16 is filled into the through recess 12 a of the light guide member 12 bonded onto the transparent substrate 11. The filling of the sealing resin 16 into the through recess 12a is preferably performed by a podding method. For the padding, a discharge device including a discharge nozzle for discharging a liquid resin (sealing resin 16) and a control unit can be used. At this time, the injection amount of the sealing resin 16 is controlled by the injection pressure.
Sealing resin 16 to be injected, the phosphor powder is in a range weight average particle diameter of 7μm or more 15μm or less with a range true density below 3 g / cm ³ or more 4.7 g / cm ^3, uncured state It is preferable that the viscosity at 25 ° C. is adjusted in the range of 4000 to 15000 mPa · s in an uncured state.
Further, the height of the liquid level of the injected sealing resin 16 can be measured by the above-described laser displacement meter (for example, ZSHLD2 manufactured by OMRON). The liquid surface height is measured before the curing heat treatment after the injection, and the injection pressure may be controlled so that the position falls within the range of −100 μm to +100 μm from the middle point connecting the end portions of the through recess 12a.

Next, the sealing resin 16 injected into the through recess 12a is cured. For example, when a thermosetting resin is used as the sealing resin, the curing process may be performed such as heating.
Thereafter, the transparent substrate 11 is cut into a desired size, whereby the light emitting device 10 shown in FIGS. 1 and 2 is obtained.

[Light emitting module]
FIG. 4 is a diagram illustrating an example of the light emitting module 1 to which the light emitting device 10 of the present embodiment is applied. FIG. 4A is a schematic plan view of the light emitting module 1 as viewed from the irradiated side, and FIG. 4B is a schematic side view of the light emitting module 1.
As shown in FIGS. 4A and 4B, the light emitting module 1 includes the light emitting device 10 shown in FIGS. 1 and 2 and a reflecting plate 2 as an example of a reflecting film on which the light emitting device 10 is loaded. I have. Note that the light emitting module 1 may be provided with a diffusing lens or the like for making the light output from the light emitting device 10 uniform, if necessary.

As shown in FIG. 4B, the reflecting plate 2 has a concave cross-sectional shape, and is configured such that the light emitting device 10 is attached to the bottom portion inside the concave portion. The reflecting plate 2 has a function of reflecting the light output from the light emitting device 10.
The reflection plate 2 is made of, for example, a metal plate. Moreover, the surface inside the recessed part to which the light-emitting device 10 is attached among the reflecting plates 2 may be painted by the white coating film etc., for example.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. Note that the description of the same configuration as in the first embodiment is omitted here.
FIG. 5 is a schematic plan view showing the light emitting device 30 to which the second embodiment of the present invention is applied. 6 is a cross-sectional view taken along line VI-VI in FIG. 5, and is a schematic cross-sectional view of the light emitting device 30 to which the second embodiment is applied.

  As shown in FIGS. 5 and 6, the light-emitting device 30 of the present embodiment includes a transparent substrate 31 as another example of a light-transmitting substrate, and a light guide member 32 as another example of a light-transmitting member. The low resistance lead 33 as another example of the metal electrode, the transparent lead 34 as another example of the translucent electrode, the light emitting element (LED) 35, and the sealing resin as another example of the sealing material 36. The basic configuration of the light emitting device 30 of the present embodiment is substantially the same as that of the light emitting device 10 (see FIG. 1) of the first embodiment, except for the light emitting element (LED) 35. That is, the transparent substrate 31, the light guide member 32, the low resistance lead 33, the transparent lead 34, and the sealing resin 36 are respectively the transparent substrate 11, the light guide member 12, the low resistance lead 13, and the transparent lead 14 of the first embodiment. And it has the same configuration as the sealing resin 16. The light guide member 32 is provided with a plurality of (four in this example) through recesses 32 a as in the light guide member 12.

Then, the structure of the light emitting element (LED) 35 of 2nd embodiment is demonstrated.
FIG. 7 is a schematic cross-sectional view of a light emitting element (LED) 35 to which the second embodiment is applied.
The light emitting element (LED) 35 according to the present embodiment includes a substrate 40, an N-type layer 41 stacked on the substrate 40, a light-emitting layer 42 stacked on the N-type layer 41, and a stack on the light-emitting layer 42. P-type layer 43, N-type electrode 44 connected to N-type layer 41, P-type transparent electrode 45 laminated on P-type layer 43, and P-type laminated on P-type transparent electrode 45 The reflective electrode 46 and a passivation film 48 that covers and protects the exposed N-type layer 41, light-emitting layer 42, P-type layer 43, N-type electrode 44, and P-type reflective electrode 46 are provided.
Further, when the light emitting element (LED) 35 is mounted on the light emitting device 30, bumps 47 provided on the N-type electrode 44 and the P-type reflective electrode 46 are formed. The light emitting element (LED) 35 is connected to the transparent lead 34 or the low resistance lead 33 via the bump 47 and is stacked on the transparent substrate 31 (see also FIGS. 5 and 6).

  The substrate 40, the N-type layer 41, the light-emitting layer 42, the P-type layer 43, the P-type transparent electrode 45 and the like of the light-emitting element (LED) 35 are the same as those in the light-emitting element (LED) 15 of the first embodiment shown in FIG. A configuration similar to that of the substrate 20, the N-type layer 21, the light emitting layer 22, the P-type layer 23, the P-type transparent electrode 25, and the like can be employed. Further, the N-type electrode 44 can have a laminated structure of the N-type ohmic electrode 24 and the N-type bonding electrode 26 of the light emitting element (LED) 15 in the first embodiment.

For the P-type reflective electrode 46, for example, aluminum, silver, an aluminum alloy, or a silver alloy having a high light reflectance can be used.
As the passivation film 48, for _example, it can be used _{SiO 2, TiO 2, Si 3} N 4, SiO 2 -Al 2 O 3, Al 2 O 3, AlN or the like.

As described above, the light emitting element (LED) 35 of the present embodiment is different from the first embodiment in that the P-type reflective electrode 46 is formed on the P-type transparent electrode 45. In the light emitting element (LED) 35 of the present embodiment, the light output from the light emitting layer 42 and traveling to the P-type reflective electrode 46 is reflected by the P-type reflective electrode 46 and travels to the substrate 40 side. Become. That is, the radiation direction of the light emitted from the light emitting element (LED) 35 is mainly in the range of 180 ° on the upper surface side (substrate 40 side) of the light emitting element (LED) 35.
Therefore, in the present embodiment, the electrodes (low resistance lead 33 and transparent lead 34) provided below the light emitting element (LED) 35 do not necessarily have transparency. However, light emitted from the light emitting element (LED) 35 is also emitted to the lower surface side of the light emitting element (LED) 35 in a region away from the element. Therefore, as in the present embodiment, by providing the transparent substrate 31 and the transparent lead 34 that are transparent to the light output from the light emitting element (LED) 35, light emission is achieved as compared with the case where this configuration is not adopted. The luminous efficiency in the device 30 is increased.

Further, as described above, in the light emitting device 30 of the present embodiment, the light output from the light emitting layer 42 of the light emitting element (LED) 35 is emitted mainly from the substrate 40 side of the light emitting element (LED) 35. Even when the area of the low resistance lead 33 provided below the light emitting element (LED) 35 is increased, it is possible to suppress a decrease in the light emission efficiency of the light emitting device 30. When the area of the low resistance lead 33 is increased, the forward voltage can be lowered and the heat dissipation characteristics through the electrodes can be improved as compared with the case where this configuration is not adopted. It becomes possible.
The surface of the low-resistance lead 13 is silver-plated, so that the light output from the light-emitting element (LED) 35 and reaching the low-resistance lead 13 can be reflected. It becomes possible to obtain the taking-out effect.

The light emitting device 30 of the present embodiment can be manufactured by the same method as the light emitting device 10 of the first embodiment (see FIG. 1).
In addition, when using an underfill agent after mounting the light emitting element (LED) 35 on the transparent substrate 31, the underfill agent does not need to be transparent. That is, as the underfill agent, a material having better adhesion to the light emitting element (LED) 15, the transparent substrate 31, and the like and having better thermal conductivity can be selected.

As described above, in the first embodiment and the second embodiment, the transparent substrates 11 and 31 on which the light emitting elements 15 and 35 are mounted, and the light emitting elements 15 and 35 on the transparent substrates 11 and 31 are mounted. The light guide members 12 and 32 provided on the surface side are configured by members having transparency to the light output from the light emitting elements 15 and 35. Further, the transparent leads 14 and 34 that supply power to the light emitting elements 15 and 35 are also configured by members having transparency to the light output from the light emitting elements 15 and 35.
By having such a configuration, in the light emitting devices 10 and 30, the light output from the light emitting elements 15 and 35 is transmitted through the transparent substrates 11 and 31, the light guide members 12 and 32, and the transparent leads 14 and 34. The light can be emitted to the outside of the light emitting device 10. Thereby, compared with the case where this structure is not employ | adopted, it can suppress that the light output from the light emitting elements 15 and 35 is absorbed by another member, and can improve the luminous efficiency in the light-emitting devices 10 and 30. FIG. It becomes possible.

In the first embodiment and the second embodiment, the configuration of the light emitting device has been described by taking the light emitting device 10 and the light emitting device 30 as examples. However, the configuration of the light emitting device is not limited to this. Light emitting element structures other than those described in the light emitting devices 10 and 30 may be employed.
For example, in the first embodiment, it is also possible to use a wire bonding type light emitting element (LED) 15. In the second embodiment, it is possible to mount a wire bonding type element by combining a reflector on the back surface of the light emitting element (LED) 35. In that case, it is preferable to mount using a gold bonding wire.

In the light emitting devices 10 and 30 of the first embodiment and the second embodiment, the light guide members 12 and 32 are provided with through recesses 12a and 32a, and the light emitting element (LED) 15 is provided inside the through recesses 12a and 32a. , 35 are arranged. However, the light guide members 12 and 32 are not necessarily provided with the through recesses 12a and 32a. For example, the plate-shaped transparent substrates 11 and 31 and the plate-shaped light guide members 12 and 32 are light emitting elements (LEDs). 15 and 35 may be sandwiched.
Even in the case of such a configuration, the light output from the light emitting elements (LEDs) 15 and 35 is transmitted to the outside of the light emitting devices 10 and 30 through the transparent substrates 11 and 31 and the light guide members 12 and 32. It becomes possible to emit light, and the light emission efficiency in the light emitting devices 10 and 30 can be improved.

  In addition to the light emitting module shown in FIG. 4, the above-described light emitting devices 10 and 30 include, for example, general illumination, traffic lights, scanner light source devices, printer exposure devices, in-vehicle illumination devices, photocatalytic light sources, and LED light sources. The present invention can also be applied to an LED display device using a dot matrix.

  Further, in the first embodiment and the second embodiment, light emitting elements (LEDs) 15 and 35 that output blue light, a phosphor that converts blue light into green light, and fluorescence that converts blue light into red light. Although the example which outputs white light using a body was demonstrated, it is not restricted to this. That is, the emission color (emission wavelength) of the light emitting elements (LEDs) 15 and 35 may be selected as appropriate, and the phosphor may be selected as appropriate. And in this invention, the light-emitting devices 10 and 30 do not necessarily need to contain fluorescent substance, and you may output the emitted light from the light emitting elements (LED) 15 and 35 as it is.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
The light emitting device 10 of the first embodiment was manufactured as Example 1, and the light emitting device 30 of the second embodiment was manufactured as Example 2. The manufacturing method of each light-emitting device 10 and 30 was performed according to description in the above-mentioned embodiment.
First, the base material as the transparent substrate 11 (transparent substrate 31) was an allyl ester resin sheet made by Showa Denko having a thickness of 0.5 mm. The light guide member 12 (light guide member 32) was similarly an allyl ester resin sheet made of Showa Denko having a thickness of 0.3 mm. As the transparent lead 14 (transparent lead 34), ITO was formed to a thickness of 0.3 μm by sputtering. For the low resistance lead 13 (low resistance lead 33), gold was formed on the transparent lead 14 (transparent lead 34) by an electrolytic plating method. The thickness at that time was 15 μm. A photolithographic method was applied to the electrode pattern. An NC router was used for drilling the light guide member 12 (light guide member 32). As the light emitting element (LED) 15 (light emitting element (LED) 35), an InGaN element (size 350 μm □, thickness 120 μm) having an emission wavelength of 450 nm was used. The bump 28 (bump 47) was made of gold, and a gold-tin eutectic electrode was formed on the surface thereof by a plating method. The mounting was performed using a flip chip bonder at 300 ° C. for 1 minute. As the sealing resin 16 (sealing resin 36), Shin-Etsu Chemical KER2600 was used. In this embodiment, the superiority of the characteristics was compared with the light output of blue light output from the light emitting element (LED) 15 (light emitting element (LED) 35) without using a phosphor.
The transparent substrate 11 (transparent substrate 31) and the light guide member 12 (light guide member 12) were joined using a sheet-like OCA tape Sumitomo 3M8172CL having a thickness of 50 μm.
Thereafter, the transparent substrate 11 (transparent substrate 31) was separated into 10 mm □ sizes with a CO ₂ laser processing machine at a pitch of 2 × 2, and the light emitting device 10 (light emitting device 30) was completed.

  Then, the light-emitting device 50 shown in FIG. 8 as a comparative example was manufactured. For the light emitting device 50 of the comparative example, a resin casing 51 having the same number of light emitting elements (LEDs) 55 having the same performance and having a white color as a whole was used. The plastic package is silver-plated on copper lead frames (53a, 53b), and the resin casing 51 uses nylon 9T (Kuraray Genestar (trade name)) containing glass fiber and titanium oxide filler. What was manufactured in was used. In the light emitting device 50, the light emitting element (LED) 55 was mounted by a wire bonding method using the same structure as the transparent electrode type light emitting element (LED) 15 described in the first embodiment. And the mounted light emitting element (LED) 55 was sealed with sealing resin 56 (manufactured by Shin-Etsu Chemical KER2600).

Next, a rated energization current of 40 mA was applied to each of the obtained light emitting devices 10, 30, and 50, and the light emission output and the forward voltage in each of the light emitting devices 10, 30, and 50 were measured.
Table 1 shows the measurement results of the light emission outputs and forward voltages of the light emitting devices 10, 30, and 50 in Examples 1 and 2 and the comparative example.

As shown in Table 1, in Examples 1 and 2, the light output of the light emitting devices 10 and 30 was in the range of 88 mW to 100 mW. On the other hand, the light emission output of the light emitting device 50 of the comparative example was 80 mW. Therefore, in Examples 1 and 2, it turned out that the light emission output of the light-emitting device 10 (light-emitting device 30) improves compared with a comparative example. Moreover, when Example 1 and Example 2 were compared, it turned out that the light-emitting device 10 of Example 1 has a high light emission output compared with the light-emitting device 30 of Example 2, and is preferable.
Further, as shown in Table 1, in Examples 1 and 2, the forward voltages of the light emitting devices 10 and 30 were 6.0 V to 6.5 V. On the other hand, the forward voltage of the light emitting device 50 of the comparative example was 6.2V. Therefore, in Example 1, 2, it turned out that the forward voltage of the light-emitting device 10 (light-emitting device 30) is comparable with a comparative example. In particular, in Example 2, it was found that the forward voltage was lower than that of the comparative example, which was preferable.
As described above, in any of the embodiments of the present invention, the light emission efficiency is improved as compared with the comparative example, and the superiority of the present invention was confirmed.

DESCRIPTION OF SYMBOLS 10 ... Light-emitting device, 11 ... Transparent substrate, 12 ... Light guide member, 12a ... Through-hole recessed part, 13 ... Low-resistance lead, 14 ... Transparent lead, 15 ... Light emitting element (LED), 16 ... Sealing resin, 20 ... Substrate, 21 ... N-type layer, 22 ... light emitting layer, 23 ... P-type layer, 24 ... N-type electrode, 25 ... P-type transparent electrode, 26 ... N-side bonding electrode, 27 ... P-type bonding electrode, 28 ... Bump, 30 ... Light emitting device, 31 ... transparent substrate, 32 ... light guide member, 32a ... through recess, 33 ... low resistance lead, 34 ... transparent lead, 35 ... light emitting element (LED), 36 ... sealing resin, 40 ... substrate, 41 ... N-type layer, 42 ... light-emitting layer, 43 ... P-type layer, 44 ... N-type electrode, 45 ... P-type transparent electrode, 46 ... P-type reflective electrode, 47 ... bump, 48 ... passivation film, 50 ... light-emitting device, 51 ... Resin casing, 53a ... Lead frame (anode ), 53b ... lead frame (cathode side), 55 ... light emitting element (LED), 56 ... sealing resin

Claims (11)

A light emitting element that emits light when energized;
The light-emitting element includes a light-transmitting electrode that is transmissive to light output from the light-emitting element and supplies power to the light-emitting element. A translucent substrate;
A light-emitting device comprising: a light-transmitting member that is transparent to light output from the light-emitting element and provided on a side of the light-transmitting substrate on which the light-emitting element is mounted.   The light-emitting device according to claim 1, wherein the translucent substrate includes at least one resin component selected from the group consisting of an allyl ester resin, an epoxy resin, and an epoxy acrylate resin.   The light-emitting device according to claim 1, wherein the translucent member includes at least one resin component selected from the group consisting of an allyl ester resin, an epoxy resin, and an epoxy acrylate resin.   The said translucent electrode is at least 1 sort (s) selected from the group which consists of ITO, IZO, IGO, a zinc oxide, a tin oxide, and silver nanowire, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The light emitting device described.   The light emitting element includes acrylic urethane resin, fluorine resin, acrylic silicone resin, urethane resin, acrylic resin, epoxy resin, polyester resin, alkyd resin, melamine resin, urea resin, guanamine resin, polyvinyl chloride, polyvinyl acetate, vinyl butyral. 5. The sealing material according to claim 1, wherein the sealing material contains at least one resin component selected from a resin, a styrene-butadiene resin, an unsaturated polyester resin, a silicone resin, and an allyl ester resin. The light emitting device according to claim 1.   The light emitting device according to claim 5, wherein the sealing material includes a phosphor.   The light-emitting device according to claim 1, wherein the translucent substrate and the translucent member are made of the same material.   The light-emitting device according to claim 1, wherein a thickness of the translucent substrate is in a range of 50 μm to 1 mm.   The light-emitting device according to claim 1, wherein a thickness of the translucent member is in a range of 100 μm to 1 mm. The translucent substrate further includes a metal electrode mounted on the translucent electrode,
The light emitting device according to any one of claims 1 to 9, wherein the light emitting element is connected to the metal electrode through a metal bump made of metal.   11. A light emitting module comprising a reflection film for controlling reflection of light output from the light emitting device outside the light emitting device according to claim 1.

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