JP2009099823A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device excellent in heat dissipation property and having directivity. <P>SOLUTION: The light-emitting device 1 comprises a substrate 3 mounted with a light-emitting element 2, a reflective frame 7 provided on the substrate 3 to surround the light-emitting element 2 and having an inner circumferential surface being a reflective surface 7a, a frame 8 provided on the substrate 3 to surround the light-emitting element 2, and a phosphor layer 10 containing a phosphor 9 performing the wavelength conversion of light from the light-emitting element 2, and sealing the light-emitting element 2 at the inside of the frame 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light emitting device in which a phosphor layer is arranged around a light emitting element.

  In recent years, light-emitting devices equipped with light-emitting elements such as light-emitting diode elements (LEDs) have been used as light sources for mobile phones and digital camera flashes, medical lighting, and automobile headlights.

  When white light emission is obtained in such a light-emitting device, a phosphor that converts the wavelength of light from the light-emitting element is arranged around the light-emitting element, and the emission color of the light-emitting element and the emission color of the phosphor are mixed. As a result, white light emission is obtained. The above-described light emitting device is disclosed in Patent Document 1, for example.

The light emitting device disclosed in Patent Document 1 has a base having a recess, a light emitting element that emits blue light disposed in the recess, and a refractive index of 1 formed in the recess so as to cover the light emitting element. A phosphor-containing resin agent comprising: a resin of 4 to 1.65; and a yellow phosphor that emits yellow light or orange light when excited by blue light emitted from the light emitting element. And a phosphor-containing resin layer having a height from the bottom surface of the concave portion at the lowest position of the upper surface to the concave portion of 60 to 85% of the depth. Thereby, since the optical path difference between the blue light emitted from the light emitting element and the yellow light emitted from the phosphor can be reduced, a light emitting device with a reduced angular color difference can be obtained.
JP 2007-201444 A

  In such a light emitting device, upon receiving the energy of light emitted from the light emitting element, the phosphor is excited and the phosphor emits light. At this time, the energy (E) at which the phosphor is excited is the same as the energy (E) necessary for the phosphor to emit light.

  However, when the light emitting element emits light continuously, the phosphor continues to be exposed to the energy of light from the light emitting element. As a result, the phosphor receives excessive energy of light from the light emitting element, and starts to be excited with energy (E + ΔE) higher than energy (E) necessary for the phosphor to emit light. Therefore, the energy (ΔE) obtained by subtracting the energy (E) necessary for the phosphor to emit light from the energy (E + ΔE) excited by the phosphor is left, and this surplus energy (ΔE) becomes the phosphor. The phosphor becomes heat inside and causes the phosphor to self-heat. The self-heating of the phosphor causes a temperature rise of the phosphor, which causes a problem that the light conversion efficiency of the phosphor is lowered and the life of the light emitting device is shortened.

  In addition to the above problems, the conventional light emitting device has the following problems.

  As described above, the phosphor emits light when excited by receiving the energy of light from the light emitting element. In the conventional light emitting device, since the phosphors are scattered inside the translucent member, a part of the light emitted from the phosphors is emitted from the light emitting device without being reflected by the reflecting frame. Therefore, there is a problem that the light emitted from the light emitting device cannot have a certain direction and the directivity cannot be obtained.

  An object of this invention is to provide the light-emitting device which is excellent in heat dissipation and has high directivity.

  In order to achieve the above object, a light-emitting device of the present invention includes a substrate on which a light-emitting element is placed, a reflective frame that is provided on the substrate so as to surround the light-emitting element, and has an inner peripheral surface serving as a reflective surface, A frame body provided on a substrate so as to surround the element, and a phosphor layer that converts the wavelength of light from the light emitting element and includes a phosphor layer that seals the light emitting element inside the frame body. It is said.

  According to the present invention, in the light emitting device configured as described above, the frame is made of a metal material.

  According to the present invention, in the light emitting device having the above structure, a conductor layer is disposed on the upper surface of the substrate, and the frame body is bonded to the conductor layer with a conductive adhesive.

  According to the present invention, in the light emitting device having the above-described configuration, the inner peripheral surface of the reflection frame body is inclined so that the opening width widens upward.

  In the light emitting device having the above configuration, the present invention is characterized in that the upper surface of the reflection frame is positioned above the frame.

  According to the present invention, the light emitting device is provided with the frame, and the phosphor layer containing the phosphor is disposed inside the frame. For this reason, even if the phosphor self-heats due to the light energy from the light emitting element, the heat of the phosphor can be absorbed by the frame. Thereby, it is possible to prevent a decrease in the light conversion efficiency of the phosphor and a shortening of the lifetime of the light emitting device by preventing the temperature rise of the phosphor caused by the self-heating of the phosphor.

  Further, even if the phosphor emits light upon receiving light from the light emitting element, it is possible to prevent the phosphor emission region from spreading outside the frame by sealing the phosphor inside the frame. Thereby, since the light of a fluorescent substance can also be reflected and emitted by a reflective frame, a strong light quantity can be given in a fixed direction, and directivity can be obtained.

  According to the invention, the frame is made of a metal material. Therefore, the heat generated from the phosphor can be absorbed more effectively.

  According to the invention, the conductor layer is disposed on the upper surface of the substrate, and the frame is bonded to the conductor layer with the conductive adhesive. Therefore, the heat generated from the phosphor and the heat generated from the light emitting element can be absorbed by the frame and the conductor layer. Thereby, heat can be absorbed more effectively by increasing the heat absorbing member. Further, the frame body is bonded to the conductor layer with a conductive adhesive. Therefore, the heat absorbed by the frame can be more easily transferred to the conductor layer.

  Moreover, according to this invention, the upper surface of a reflective frame is comprised so that it may be located above a frame. Therefore, more light emitted from the frame can be reflected by the reflecting surface of the reflecting frame, and thus the directivity can be more effectively obtained.

  Further, according to the present invention, the inner peripheral surface of the reflection frame body is inclined so that the opening width increases upward. Therefore, the directivity can be changed by changing the inclination angle of the reflecting surface.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an overall perspective view of the light emitting device according to the present embodiment. FIG. 2 is a plan view seen from the top surface of the light emitting device according to the present embodiment. FIG. 3 is a plan view seen from the bottom surface of the light emitting device according to this embodiment. FIG. 4 is a cross-sectional view of the light emitting device of the present embodiment when the section AB shown in FIG. 1 is cut in the thickness direction. FIG. 5 shows an enlarged cross-sectional view of a region where the frame of the light emitting device in this embodiment is arranged.

  As shown in FIG. 1, the light-emitting device 1 according to the present embodiment includes a light-emitting element 2, a substrate 3 on which the light-emitting element 2 is placed, and a plurality of light-emitting devices 1 provided on both surfaces of the substrate 3 and formed in a predetermined pattern. Wiring layers 4a and 4b, conductor layers 5a and 5b that absorb heat in the light emitting device 1, bonding wires 6a and 6b for electrically connecting the light emitting element 2 and the wiring layers 4a and 4b, and light emission A reflective frame 7 that is installed on the upper surface of the substrate 3 so as to surround the element 2 and whose inner peripheral surface is the reflective surface 7 a, and a reflective frame 7 that is installed on the upper surface of the substrate 3 so as to surround the light emitting element 2. A cylindrical frame 8 disposed inside the opening, a phosphor layer 10 containing a phosphor 9 that seals the inside of the frame 8, and a light emitting element provided inside the reflective frame 7 And a translucent member 11 (see FIG. 4).

  The substrate 3 is made of an insulator using a sintered body such as aluminum oxide, ceramics such as glass ceramics, or a resin such as epoxy resin.

  The wiring layers 4a and 4b and the conductor layers 5a and 5b are fixed to both surfaces of the substrate 3 with an adhesive or the like. The wiring layers 4a and 4b and the conductor layers 5a and 5b are both formed in a predetermined pattern by removing a predetermined region of the metal foil using a photolithography technique and an etching technique.

  As shown in FIG. 2, the wiring layer 4 a provided on the upper surface of the substrate 3 is provided at a position separated from the outer peripheral portion of the frame body 8. Further, the conductor layer 5a is provided in a region on the upper surface of the substrate 3 excluding a region where the wiring layer 4a is provided. A groove 12 is formed in the outer peripheral portion of the wiring layer 4a along the shape of the wiring layer 4a, and the inside of the groove 12 is sealed with an insulating material 13 such as a resist. Therefore, the wiring layer 4a and the conductor layer 5a are electrically insulated.

  As shown in FIG. 3, the conductor layer 5b is provided at the center of the substrate 3 on the lower surface of the substrate 3, and is branched in two directions at the left and right ends. On the lower surface of the substrate 3, a pair of wiring layers 4 b are provided in parallel to the end portions of the substrate 3. An insulating material 13 such as a resist is provided between the wiring layer 4b and the conductor layer 5b. Thereby, the wiring layer 4b and the conductor layer 5b are electrically insulated.

  As shown in FIG. 4, the wiring layer 4 a located on the upper surface of the substrate 3 and the wiring layer 4 b located on the lower surface of the substrate are electrically connected by a through hole 15 a provided in the substrate 3. The through hole 15a is formed by making a hole in the substrate 3 using a laser or the like and then plating the inside of the hole. The conductor layer 5 a located on the upper surface of the substrate 3 and the conductor layer 5 b located on the lower surface of the substrate 3 are electrically connected by a through hole 15 b provided in the substrate 3.

  The light emitting element 2 and the wiring layer 4a are electrically connected via bonding wires 6a and 6b made of fine metal wires such as gold (Au) and aluminum (Al). The bonding wire 6 is fixed to the light emitting element 2 and the wiring layer 4a by soldering or the like.

  Thereby, a current is supplied to the wiring layer 4b from an external electrode (not shown) disposed under the light emitting device 1, whereby a current is supplied to the wiring layer 4a through the through hole 15a provided in the substrate 3. . Since the wiring layer 4a is electrically connected to the light emitting element 2 through the bonding wire 6, the current supplied to the wiring layer 4a is supplied to the light emitting element 2 so that the light emitting element 2 can emit light.

  The reflective frame 7 is made of a metal such as aluminum (Al) or iron (Fe) -nickel (Ni) -cobalt (Co) alloy, a sintered body such as aluminum oxide, a ceramic such as glass ceramics, or a resin such as an epoxy resin. It becomes more. As shown in FIG. 2, the reflection frame 7 is fixed via an adhesive or the like on the conductor layer 5 a disposed on the upper surface of the substrate 3 so as to surround the light emitting element 2 provided on the substrate 3. The reflection frame 7 has a reflection surface 7a on the inner peripheral surface, and the reflection surface 7a is plated or vapor-deposited using a metal such as aluminum (Al) or copper (Cu) in order to increase the light reflection efficiency. Cover with a metal coating. Further, as shown in FIG. 4, the reflection surface 7a is inclined so that the opening width is widened upward by cutting or molding. Therefore, the directivity can be changed by changing the inclination angle of the reflecting surface 7a.

  Further, the inside of the reflection frame 7 is sealed with a translucent member 11 made of silicon resin, epoxy resin, glass or the like having high transmittance. Thereby, since the bonding wire 6 which electrically connects the light emitting element 2 and the wiring layer 4a can be sealed with the translucent member 11, the connection portion of the bonding wire 6 is disconnected due to vibration during product transportation. In addition, disconnection of the bonding wire 6 can be prevented.

  The frame 8 is made of a material having good thermal conductivity using a metal such as copper (Cu) or aluminum (Al). As shown in FIG. 4, the frame body 8 has a circular cylindrical shape, and is made of an adhesive made of a conductive adhesive such as a silver paste so that the light emitting element 2 is arranged at the center on the upper surface of the conductor layer 5 a. The frame body is bonded and fixed using the layer 14. Note that the frame body 8 is formed by cutting or molding. The inside of the frame 8 is sealed with a phosphor layer 10 containing a phosphor 9 that converts the wavelength of light from the light emitting element 2.

  Here, the upper surface of the reflection frame 7 is configured to be positioned above the frame 8. Therefore, more light emitted from the light emitting element 2, wavelength-converted by the phosphor layer 10, and emitted from the frame 8 can be reflected by the reflecting surface 7 a of the reflecting frame 7. Thereby, directivity can be obtained more effectively.

  The light emitting device 1 in the present embodiment is a white light emitting device. Therefore, the light emitting element 2 is a blue light emitting diode using gallium nitride (GaN) as a material. The light emitting element 2 is bonded to the conductor layer 5 a through the adhesive layer 14. And the fluorescent substance 9 contained in the fluorescent substance layer 10 which seals the inner side of the frame 8 consists of yttrium aluminum garnet (YAG). As a result, blue light emitted from the light emitting element 2 excites the phosphor 9 covering the periphery of the light emitting element 2 to cause yellow light emission, and white light is obtained by a mixture of blue light emission and yellow light emission.

  In the present embodiment, the phosphor 9 is contained only inside the frame body 8. Therefore, the phosphor layer 10 having a high concentration of the phosphor 9 can be disposed around the light emitting element 2. Thereby, since wavelength conversion efficiency becomes high, the light emission which approached white more can be obtained. In addition, since the phosphor layer 10 is provided only inside the frame body 8, the distance (path length) between the phosphor 9 and the light emitting element 2 can be made to be uniform, thereby reducing variations in wavelength conversion efficiency and luminance. Unevenness can be suppressed.

  In FIG. 5, the path through which heat of the light emitting element 2 and the phosphor 9 is transferred is indicated by solid arrows. Note that, since the light emitting element 2 also rises in temperature due to light emission energy and the light emission efficiency is lowered, in the light emitting device using the light emitting diode (LED) as the light emitting element 2, it is necessary to dissipate the heat of the light emitting element 2 as well.

  The heat radiated from the light emitting element 2 is absorbed by the conductor layer 5 a disposed on the upper surface of the substrate 3 through the adhesive layer 14. The heat absorbed by the conductor layer 5a is transferred to the conductor layer 5b disposed on the lower surface of the substrate 3 through the through hole 15b. Then, heat is radiated to the outside of the light emitting device 1 from the conductor layer 5 b disposed on the lower surface of the substrate 3.

  The heat radiated from the phosphor 9 is absorbed by the frame 8 or the conductor layer 5 a disposed on the upper surface of the substrate 3. Therefore, the heat generated from the phosphor 9 and the heat generated from the light emitting element 2 can be absorbed by the frame 8 and the conductor layer 5a. Thereby, by further providing the conductor layer 5a and increasing the heat absorbing member, it is possible to absorb heat more effectively. The heat absorbed by the frame 8 is transferred to the conductor layer 5 a disposed on the upper surface of the substrate 3 through the adhesive layer 14. The heat transferred to the conductor layer 5a disposed on the upper surface of the substrate 3 is transferred to the conductor layer 5b disposed on the lower surface of the substrate 3 through the through hole 15b. Then, heat is radiated to the outside of the light emitting device 1 from the conductor layer 5 b disposed on the lower surface of the substrate 3.

  Here, a conductive adhesive is used for the adhesive layer 14 when the frame 8 and the light emitting element 2 are bonded to the conductor layer 5a. Therefore, the heat absorbed by the frame body 8 can be more easily transferred to the conductor layer 5a.

  Further, since the frame body 8 is made of metal, the heat generated from the phosphor 9 can be absorbed more effectively.

  Although not shown, in the light emitting device 1 of the present embodiment, the heat radiation can be performed more efficiently by providing a heat sink or the like below the conductor layer 5b.

  From the above, in the light emitting device 1 according to the present embodiment, when a current flows through the wiring layer 4a, a current is supplied to the light emitting element 2 via the bonding wires 6a and 6b. Electron recombination occurs and electrons are excited. When the excited electrons return to the ground state, light emission occurs, and light is emitted from the light emitting element 2. The light emitted from the light emitting element 2 excites the phosphor 9 that seals the inside of the frame body 8 arranged around the light emitting element 2 to emit the phosphor 9. The emission color of the phosphor 9 is mixed to obtain a predetermined emission color. The light emitted from the upper part of the frame body 8 is reflected by the reflection surface 7a of the reflection frame body 7 and is emitted from the light emitting device 1 in a predetermined direction.

  According to the present embodiment, the light emitting device 1 is provided with the frame 8, and the phosphor layer 10 containing the phosphor 9 is disposed inside the frame 8. For this reason, even if the phosphor 9 undergoes self-heating due to the light energy from the light emitting element 2, the heat of the phosphor 9 can be absorbed by the frame 8. Thereby, it is possible to prevent a decrease in the light conversion efficiency of the phosphor 9 and a shortening of the lifetime of the light emitting device 1 by preventing the temperature rise of the phosphor 9 caused by the self-heating of the phosphor 9.

  Further, even when the phosphor 9 emits light upon receiving light from the light emitting element 2, the phosphor 9 is sealed inside the frame 8, so that the light emitting region of the phosphor 9 is spread outside the frame 8. Can be prevented. Thereby, since the light of the fluorescent substance 9 can also be made to reflect and be emitted by the reflective frame 7, a strong light quantity can be given to a fixed direction and directivity can be obtained.

  In the present embodiment, a white light emitting device is used. However, the light emitting device of the present invention is not limited to white light emission, and light emission in which a phosphor layer 10 containing a phosphor 9 is arranged around the light emitting element 2. If it is an apparatus, it can implement suitably.

  INDUSTRIAL APPLICABILITY The present invention can be used for a light emitting device having excellent heat dissipation and directivity.

It is an isometric view in the light-emitting device of this embodiment. It is the top view seen from the upper surface in the light-emitting device of this embodiment. It is the top view seen from the lower surface in the light-emitting device of this embodiment. It is sectional drawing in the light-emitting device of this embodiment. It is sectional drawing of the light-emitting device of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Light emitting element 3 Board | substrate 4 Wiring layer 5 Conductor layer 6 Bonding wire 7 Reflective frame 8 Frame 9 Phosphor 10 Phosphor layer 11 Translucent member 12 Groove 13 Insulating material 14 Adhesive layer 14 Through hole

Claims (5)

A substrate on which a light emitting element is mounted;
A reflective frame provided on the substrate so as to surround the light emitting element, and having an inner peripheral surface as a reflective surface;
A frame provided on the substrate so as to surround the light emitting element;
A light emitting device comprising: a phosphor that converts the wavelength of light from the light emitting element; and a phosphor layer that seals the light emitting element inside the frame.   The light emitting device according to claim 1, wherein the frame is made of a metal material.   The light emitting device according to claim 1, wherein a conductor layer is disposed on an upper surface of the substrate, and the frame body is bonded to the conductor layer with a conductive adhesive.   The light emitting device according to any one of claims 1 to 3, wherein an upper surface of the reflective frame is configured to be positioned above the frame.   The light emitting device according to any one of claims 1 to 4, wherein an inner peripheral surface of the reflection frame body is inclined so that an opening width widens upward.

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