JP4129173B2 - Light emitting element storage package and light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light-emitting element storage package and a light-emitting device for storing a light-emitting element, which are used in a display device using a light-emitting element such as a light-emitting diode.
[0002]
[Prior art]
Conventionally, a ceramic package has been used as a light-emitting element storage package (hereinafter also referred to as a package) for storing light-emitting elements such as light-emitting diodes, and an example thereof is shown in FIG. Reference 1). As shown in the figure, the conventional package has a plurality of ceramic layers laminated, a recess 14 formed on the top surface, and a mounting portion conductor layer 12 comprising a conductor layer for mounting the light emitting element 13 on the bottom surface. (Hereinafter also referred to as a mounting portion) a substantially rectangular parallelepiped insulating base 11, and a wiring layer 15 comprising a pair of metallized wiring conductors led out from the mounting portion 12 of the insulating base 11 and its periphery to the lower surface of the insulating base 11. And is composed mainly of.
[0003]
Then, the light emitting element 13 is placed and fixed on the mounting portion 12 to which one end of one wiring layer 15 is electrically connected via a conductive adhesive, solder, etc., and the electrode of the light emitting element 13 and the other wiring The layer 15 is electrically connected via the bonding wire 16, and then the light emitting device 13 is sealed by filling the recess 14 of the insulating substrate 11 with a transparent resin and sealing the light emitting element 13.
[0004]
Since many of the light emitting devices are arranged so as to be adjacent to each other, the light emitted from the light emitting element 13 mounted on the mounting portion 12 is transmitted through the insulating base 11 in the ceramic package. Thus, in order to effectively prevent light from mixing between adjacent light emitting devices, the insulating base 11 made of black ceramics is used. Further, in order to reflect the light of the light emitting element 13 on the inner surface of the recess 14 and to emit light above the package, the metallization having a nickel (Ni) plating layer or a gold (Au) plating layer on the inner surface of the recess 14 on the surface. A metal layer 17 composed of layers may be applied.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-232017 [0006]
[Problems to be solved by the invention]
However, in the conventional package described above, an exposed ceramic is exposed between the mounting portion 12 and the wiring layer 15 of the insulating base 11 and the metal layer 17 on the inner surface of the recess 14 in order to prevent an electrical short circuit. In the case of using black ceramics, the light from the light emitting element 13 is absorbed by the exposed area, and as a result, the light from the light emitting element 13 can be efficiently emitted above the package. There was a problem that it was not possible.
[0007]
In addition, when white ceramic is used for the insulating base 11 and the thickness thereof is increased, the light of the light emitting element 13 can be efficiently reflected on the surface of the insulating base 11 without being absorbed by the insulating base 11. Although light can be efficiently emitted to the outside of the package, there is a problem that the package becomes large. On the other hand, when the insulating base 11 is thinned, the package is downsized, but a part of the light of the light emitting element 13 passes through the insulating base 11 and leaks to the outside, which reduces the light emission efficiency of the light emitting device. There is also a problem in that light from adjacent light emitting devices is mixed in color.
[0008]
Furthermore, when the mounting portion 12 is formed on the entire bottom surface of the recess 14 and the wiring layer 15 is formed around the inner surface of the recess 14 or around the recess 14 on the top surface of the insulating substrate 11, it is difficult to connect the bonding wires 16 or light emission. There was a problem that the apparatus itself was enlarged.
[0009]
Accordingly, the present invention has been completed in view of the above-described conventional problems, and an object of the present invention is to effectively prevent the light of the light emitting element from being absorbed by the insulating base and to reduce the light of the light emitting element. It is an object of the present invention to provide a light-emitting element storage package that can be prevented from passing through an insulating substrate and leaking outside, and a light-emitting device that uses the light-emitting element and has a very high light emission efficiency.
[0010]
[Means for Solving the Problems]
According to one aspect of the present invention, the light emitting element storage package includes a white insulating base, a mounting portion conductor layer, and a wiring layer. The light emitting element storage package further includes two external terminal conductor layers and a central conductor layer. The insulating base has an upper surface and a lower surface provided with a recess. The mounting portion conductor layer is provided on the bottom surface of the recess, and the light emitting element is mounted thereon. The wiring layer is provided on the bottom surface of the recess and is electrically connected to the light emitting element. The two external terminal conductor layers are provided at the end of the lower surface of the insulating base. The central conductor layer is located between the two external terminal conductor layers so as to overlap the region corresponding to the region where the insulating substrate between the mounting portion conductor layer and the wiring layer is exposed. Located in the center.
[0011]
In the light emitting element storage package of the present invention, since the central conductor layer is formed between the external terminal conductor layers on the lower surface of the insulating base so as to overlap the exposed area of the insulating base on the bottom of the recess, Even if a part of the light of the light emitting element can be transmitted through the bottom of the insulating substrate because the bottom is thin, the light transmitted through the bottom of the insulating substrate is reflected by the central conductor layer, so that Light loss due to transmission through the bottom of the substrate can be prevented and light can be efficiently emitted to the outside, and the thickness is reduced.
[0012]
The light emitting device of the present invention includes a light emitting element storage package of the present invention, a light emitting element mounted on the mounting portion conductor layer and electrically connected to the wiring conductor around the mounting portion conductor layer, And a transparent resin covering the light emitting element.
[0013]
The light emitting device of the present invention has high luminous efficiency and is thinned by the above configuration.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The light emitting element storage package of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an example of an embodiment of a package of the present invention, in which 1 is an insulating substrate, 2 is a mounting portion for a light emitting element 3, and 4 is a recess for housing the light emitting element 3. It is.
[0015]
The package of the present invention is provided with a recess 4 for accommodating the light emitting element 3 on the upper surface of the insulating base 1, and a mounting portion conductor layer (hereinafter also referred to as a mounting portion) 2 on which the light emitting element 3 is mounted on the bottom surface of the recess 4. And wiring layers 5a and 5b to which the electrodes of the light emitting element 3 are connected, and external terminal conductor layers 8a and 8b electrically connected to the wiring layers 5a and 5b are formed at both ends of the lower surface of the insulating substrate 1. A central conductor layer 9 is formed between the external terminal conductor layers on the lower surface of the insulating base so as to overlap the region R2 (FIG. 1) where the insulating base 1 is exposed on the bottom of the recess.
[0016]
In FIG. 1, R1 indicates a region of the bottom surface of the recess 4 where the insulating base 1 is not exposed.
[0017]
The insulating substrate 1 of the present invention is preferably made of white ceramics. If colored ceramics such as black are used, the light that is transmitted through the insulating substrate 1 is absorbed by the insulating substrate 1, and the central conductor layer 9. Therefore, it is very difficult to reflect the light efficiently and radiate it to the outside (upward in FIG. 1).
[0018]
The insulating substrate 1 of the present invention is a substantially rectangular parallelepiped or a substantially rectangular flat plate made of a sintered body (ceramics) such as an aluminum oxide (Al ₂ O ₃ ) sintered body or an aluminum nitride (AlN) sintered body. These white ceramics can make the reflectance of light having a wavelength of 400 to 700 nm 80% or more when the thickness of the insulating substrate 1 is 0.8 mm or more.
[0019]
For example, when the insulating substrate 1 is made of an aluminum oxide sintered body, it is made of a ceramic such as SiO ₂ —Al ₂ O ₃ —MgO—ZnO ₂ —CaO. In this case, when the thickness of the insulating substrate 1 is 0.8 mm or more, in order to set the reflectance of light having a wavelength of 400 to 700 nm to 80% or more, the content of Al ₂ O ₃ is 90 to 99% by weight, SiO ₂ The total content of MgO and CaO is preferably 1 to 10% by weight. If the total content of SiO ₂ , MgO, and CaO is less than 1% by weight, the sinterability of Al ₂ O ₃ is deteriorated, and it is difficult to obtain sufficient hardness as a package. When it exceeds 10% by weight, heat resistance and mechanical strength are lowered and thermal conductivity is lowered.
[0020]
In addition, SiO ₂ is contained in the ceramics in order to enhance the sinterability and adhesion of the ceramics, and MgO and CaO are included in the ceramics in order to improve the sinterability and thermal conductivity of the ceramics. ₂ , MgO and CaO are each preferably contained in an amount of 0.01% by weight or more. Further, ZrO ₂ may be contained in the ceramics in order to increase the density and mechanical strength of the ceramics. In this case, the content of ZrO ₂ is preferably 0.01 to 10% by weight. When the content is less than 0.01% by weight, the effect of improving the density and mechanical strength of the ceramic is not sufficiently exhibited. If it exceeds 10% by weight, the electrical insulation properties deteriorate. Further, if the total content of SiO ₂ , MgO, CaO and ZrO ₂ is too large, the heat resistance and strength are impaired, and therefore it is preferably 10% by weight or less.
[0021]
The insulating substrate 1 may consist of aluminum nitride (AlN) quality sintered body consists AlN-Er ₂ O ₃ system or the like of the ceramic, the thickness of the insulating base 1 is the wavelength at 0.8mm or more is 400 to 700nm light In order for the reflectance to be 80% or more, the content of Er ₂ O ₃ is preferably 1 to 10% by weight with respect to the total weight of the aluminum nitride sintered body. When the content of Er ₂ O ₃ is less than 1% by weight, the sinterability is deteriorated and it is difficult to obtain sufficient hardness. If it exceeds 10% by weight, the heat resistance and mechanical strength are lowered and the thermal conductivity is lowered.
[0022]
The insulating base 1 has a recess 4 for accommodating the light emitting element 3 on its upper surface, and is formed by laminating a plurality of ceramic layers. For example, a plurality of frame-shaped ceramic green sheets in which through holes for the recesses 4 are formed and flat ceramic green sheets for mounting the light-emitting elements 3 are laminated, fired at about 1600 ° C., and integrated. It is formed with. Also, a frame body is produced by laminating and firing one or more frame-shaped ceramic green sheets, and a rectangular parallelepiped bottom plate by laminating and firing one or more flat-plate ceramic green sheets. The insulating substrate 1 may be manufactured by manufacturing the parts and then joining them.
[0023]
Further, a mounting portion 2 for mounting the light emitting element 3 is formed on the bottom surface of the recess 4 of the insulating substrate 1, and the mounting portion 2 is made of tungsten (W), molybdenum (Mo), copper (Cu), silver ( It consists of a metallized layer of metal powder such as Ag).
[0024]
The insulating base 1 is formed with a wiring layer 5a led out from the mounting portion 2 to the lower surface and a wiring layer 5b led out from the periphery of the mounting portion 2 to the lower surface. The pair of wiring layers 5a and 5b is made of a metallized layer of metal powder such as W or Mo, and is a conductive path for electrically connecting the light emitting element 3 housed in the package to the outside. A light emitting element 3 such as a light emitting diode is fixed to the mounting portion 2 with a conductive bonding material such as a gold (Au) -silicon (Si) alloy or Ag-epoxy resin, and the mounting portion 2 of the wiring layer 5b is fixed. The electrode of the light emitting element 3 is electrically connected to the peripheral part through the bonding wire 6.
[0025]
It should be noted that a metal having excellent corrosion resistance such as nickel (Ni), gold (Au), Ag or the like is deposited on the exposed surfaces of the wiring layers 5a and 5b and the mounting portion 2 in a thickness of about 1 to 20 μm. It is possible to effectively prevent the wiring layers 5a and 5b and the mounting portion 2 from being oxidized and corroded, and to firmly fix the mounting portion 2 and the light emitting element 3 and to bond the wiring layer 5b and the bonding wire 6 together. it can. Therefore, on the exposed surfaces of the wiring layers 5a and 5b and the mounting portion 2, an Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer or an Ag plating layer having a thickness of about 0.1 to 3 μm are formed by an electroplating method or non-plating method. More preferably, the electrodes are sequentially deposited by electrolytic plating.
[0026]
In addition, a metal layer 7 is formed on the inner surface of the recess 4, and this metal layer 7 is made of a metallized layer of metal powder such as W or Mo. Further, on the metal layer 7, a metal such as Ni, Au, Ag, etc. A plating layer is applied.
[0027]
The wiring layer 5b and the mounting portion 2 on the bottom surface of the recess 4 and the metal plating layer on the surface of the metal layer 7 function as a reflection region that effectively reflects the light of the light emitting element 3 accommodated in the recess 4. For this reason, the metal layer 7 may be connected to either the wiring layer 5b or the mounting portion 2 in order to reduce the region exposed at the bottom surface of the recess 4 and improve the reflection performance.
[0028]
Moreover, it is preferable that the angle formed between the inner surface and the bottom surface of the recess 4 is 35 to 70 ° so that the inner surface of the recess 4 becomes an inclined surface that gradually spreads outward (upward in FIG. 1). In this case, the light reflected by the wiring layers 5a and 5b on the bottom surface of the recess 4 and the metal plating layer on the surface of the mounting portion 2 and the metal layer 7 can be efficiently emitted outside the package. If the angle is less than 35 °, it is difficult to stably and efficiently form the inner surface of the recess 4 at such an angle by punching the ceramic green sheet with a mold, and the package becomes extremely large. If it exceeds 70 °, it will be difficult to satisfactorily reflect the light emitted from the light emitting element 3 accommodated in the recess 4 to the outside.
[0029]
Moreover, it is preferable that the cross-sectional shape of the recessed part 4 is circular. In this case, the light emitted from the light emitting element 3 accommodated in the recess 4 can be uniformly reflected in all directions by the metal plating layer on the surface of the metal layer 7 on the inner surface of the recess 4 and can be radiated to the outside very uniformly. There is.
[0030]
The external terminal conductor layers 8a and 8b are electrically connected to the wiring layers 5a and 5b and are formed at both ends of the lower surface of the insulating base 1, and metallized with a metal powder such as W, Mo, Cu, or Ag. Consists of layers.
[0031]
The external terminal conductor layers 8a and 8b are preferably coated with a metal having excellent corrosion resistance, such as Ni, Au, and Ag, on the surface thereof to a thickness of about 1 to 20 μm. The external terminal conductor layers 8a and 8b Can be effectively prevented from being oxidized and corroded, and the lower surface of the insulating substrate 1 can be connected to an external electric circuit board via a bonding material such as solder.
[0032]
Furthermore, the external terminal conductor layers 8a and 8b may be extended to the side surface of the insulating base 1, and light can be prevented from leaking from the side of the insulating base 1 to the outside. In this case, the external terminal conductor layers 8a and 8b are preferably formed on the side surface of the insulating base 1 so as to extend to ¼ or more of the height between the lower surface and the bottom surface of the concave portion 4 so that the light is insulated. It is possible to more effectively prevent leakage from the side surface of the substrate 1 to the outside.
[0033]
The central conductor layer 9 of the present invention is formed between the external terminal conductor layers 8a and 8b on the lower surface of the insulating base 1, and the central conductor layer 9 includes the mounting portion 2 and the wiring layer 5a, The insulating base 1 between 5b is disposed so as to overlap the exposed region R2. As a result, part of the light that has entered and transmitted from the region R2 to the bottom of the insulating base 1 is reflected by the central conductor layer 9 covering the region R2, and prevents light from leaking outside from the lower surface of the insulating base 1. be able to.
[0034]
In this case, the light that enters the bottom of the insulating base 1 from the region R2 has a component in a direction (oblique direction) that is not orthogonal to the bottom surface. Therefore, by covering R1 with the central conductor layer 9 as well, It can reflect light. The central conductor layer 9 is preferably formed in a wide area, and can effectively prevent the light in the oblique direction from being reflected and leaked to the outside.
[0035]
Of the region R2 in which the bottom surface around the mounting portion 2 is exposed, the region R2 in which the bottom surface of the insulating base 1 between the mounting portion 2 and the wiring layer 5b is exposed is large, and the portion immediately below this region R2 is the center. By being covered with the partial conductor layer 9, leakage of light to the outside can be effectively prevented.
[0036]
The central conductor layer 9 is made of a metallized layer of metal powder such as W, Mo, Cu, and Ag, and the surface thereof is covered with a metal having excellent corrosion resistance such as Ni, Au, and Ag in a thickness of about 1 to 20 μm. The central conductor layer 9 can be effectively prevented from being oxidized and corroded, and the light that has entered the region R2 where the bottom surface of the concave portion 4 is exposed and has passed through the bottom portion of the insulating substrate 1 is reflected well. It is possible to effectively prevent light from leaking to the outside. Therefore, a Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer or an Ag plating layer having a thickness of about 0.1 to 3 μm are formed on the surface of the central conductor layer 9 by an electrolytic plating method or an electroless plating method. More preferably, it is deposited sequentially.
[0037]
In the present invention, the central conductor layer 9 is preferably slightly thicker than the external terminal conductor layers 8a and 8b. In this case, the lower surface of the insulating substrate 1 is reliably bonded to the external electric circuit board or package at the portion of the central conductor layer 9 having a large area, heat dissipation is improved, and solder or the like is used in the external terminal conductor layers 8a and 8b. As the amount of brazing material increases, a large meniscus of brazing material is formed, and the bonding strength of the external terminal conductor layers 8a and 8b increases. As a result, the bonding properties of the external terminal conductor layers 8a and 8b are improved, the resistance of the bonding portion is reduced, and the light emission efficiency of the light emitting element 3 is improved.
[0038]
Thus, in the package of the present invention, the central conductor layer 9 is disposed so as to overlap the region R2 where the insulating base 1 is exposed between the mounting portion 2 on the bottom surface of the recess 4 and the wiring layers 5a and 5b. Therefore, even if a part of the light of the light emitting element 3 can pass through the bottom of the insulating substrate 1 because the bottom of the insulating substrate 1 is thin, the light transmitted through the bottom of the insulating substrate 1 is in the center. Light loss is prevented by being reflected by the conductor layer 9 and passing through the bottom of the insulating substrate 1, and the light can be efficiently emitted to the outside, and the package is reduced in thickness.
[0039]
It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, as shown in the cross-sectional view of the package shown in FIG. 3, external connections formed on both ends of the lower surface of the insulating base 1 in order to firmly connect the lower surface of the package to the external electric circuit board via a bonding material such as solder. The terminal conductor layers 8a and 8b are enlarged, and the external terminal conductor layers 8a and 8b are overlapped with the exposed region R3 between the mounting portion conductor layer 2 and the metal layer 7 and between the wiring layer 5b and the metal layer 7, respectively. 8b may be formed. In this case, part of the light that has entered and transmitted from the region R3 to the bottom of the insulating base 1 is reflected by the external terminal conductor layers 8a and 8b covering the region R3, and the light leaks outside from the lower surface of the insulating base 1. Can be prevented. Therefore, in this case, the central conductor layer 9 is formed so as to overlap with the exposed region R2 between the mounting portion 2 on the bottom surface of the recess 4 for accommodating the light emitting element 3 and the wiring layer 5b. It only has to be.
[0040]
【The invention's effect】
The light emitting element storage package of the present invention is provided with a concave portion for accommodating the light emitting element on the upper surface of the insulating base, and the mounting portion conductor layer on which the light emitting element is mounted and the light emitting element are electrically connected to the bottom surface of the concave portion. And two external terminal conductor layers electrically connected to the wiring layer and the mounting portion conductor layer, respectively, are formed at both ends of the lower surface of the insulating base, Since the central conductor layer is formed between the external terminal conductor layers on the lower surface of the recess so as to overlap the exposed area of the insulating base on the bottom of the recess, the bottom of the insulating base is thin, so that part of the light of the light emitting element is Even if it is possible to transmit the bottom of the insulating base, the light transmitted through the bottom of the insulating base is reflected by the central conductor layer, so light loss due to transmission through the bottom of the insulating base is reduced. Prevent light and improve efficiency It is possible to radiate to the outside, and those thin.
[0041]
A light-emitting device of the present invention covers a light-emitting element storage package of the present invention, a light-emitting element mounted on a mounting portion conductor layer and electrically connected to a wiring conductor around the mounting portion conductor layer, and covering the light emitting element By providing the transparent resin, the luminous efficiency is high and the thickness is reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a light-emitting element storage package according to the present invention.
2 is a bottom view of the light emitting element storage package of FIG. 1; FIG.
FIG. 3 is a cross-sectional view showing another example of the embodiment of the light emitting element storage package of the present invention.
4 is a bottom view of the light emitting element storage package of FIG. 3. FIG.
FIG. 5 is a cross-sectional view of a conventional light emitting element storage package.
6 is a bottom view of the light emitting element storage package of FIG. 5. FIG.
[Explanation of symbols]
1: Insulating substrate 2: Mounting portion conductor layer 3: Light emitting element 4: Recesses 5a, 5b: Wiring layers 8a, 8b: External terminal conductor layer 9: Center portion conductor layer

Claims (3)

  A white insulating substrate having an upper surface and a lower surface provided with a recess;
  A mounting portion conductor layer provided on the bottom surface of the recess, on which the light emitting element is mounted;
  A wiring layer provided on the bottom surface of the recess, to which the light emitting element is electrically connected;
  Two external terminal conductor layers provided at the end of the lower surface of the insulating base;
  The lower surface of the insulating substrate between the two external terminal conductor layers so as to overlap the region corresponding to the exposed region of the insulating substrate between the mounting portion conductor layer and the wiring layer. A central conductor layer disposed in the central part of
A package for storing light emitting elements.   The light emitting element storage package according to claim 1, wherein the central conductor layer is thicker than the external terminal conductor layer.   The light emitting element storage package according to claim 1 or 2,
  A light emitting element that is electrically connected to the wiring layer of the light emitting element storage package and is mounted on the mounting portion conductor layer;
A light emitting device comprising:

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