JP3914887B2 - 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 housing package and a light emitting device for housing a light emitting element such as a light emitting diode (LED).
[0002]
[Prior art]
Conventionally, light-emitting devices using light-emitting elements such as light-emitting diodes (LEDs) and semiconductor lasers (LDs) are attracting attention as they are expected to further reduce power consumption and extend their lives in the future, and have been used in various fields in recent years. I'm starting. FIG. 2 shows a cross-sectional view of a conventional light emitting element storage package (hereinafter also simply referred to as a package) on which a conventional light emitting element that emits visible light from red, for example, is mounted.
[0003]
As shown in FIG. 2, the conventional package 11 has a base 12 made of various resins, ceramics and the like. A conductive paste containing tungsten (W), molybdenum (Mo), manganese (Mn) or the like is sintered at a high temperature on the substrate 12, and a nickel (Ni) plating layer or a gold (Au) plating layer is formed on the upper surface by plating. A wiring conductor 13 is formed by adhering. Electric power and drive current can be supplied from the external electric circuit to the light emitting element 15 mounted inside the package via the wiring conductor 13.
[0004]
The base body 12 is provided with a frame body 14 having a through hole penetrating the upper and lower surfaces and having a square shape in a plan view and made of resin, ceramics, or the like. The frame body 14 is bonded to the base 12 with an epoxy resin adhesive 16.
[0005]
The light emitting element 15 is die-bonded to the central portion of the upper surface of the base 12 with a resin adhesive or Ag paste (resin containing Ag particles), and the electrode of the light emitting element 15 is connected to the wiring conductor 13 provided on the base 12 and Au It is electrically connected by a bonding wire made of metal.
[0006]
Further, a transparent member 18 is provided inside the frame body 14 in order to protect the light emitting element 15. The transparent member 18 is provided by filling the inside of the frame body 14 with a thermosetting epoxy resin or the like so as to cover the light emitting element 15 and heat curing. Further, the transparent member 18 also has a function of firmly fixing the light emitting element 15 in the package 11 by being in close contact with the light emitting element 15, the base body 12, and the frame body 14.
[0007]
Further, a translucent plate-like lid 17 made of glass, sapphire or the like is bonded to the upper surface of the frame 14 with a resin adhesive or the like. As a result, a light emitting device having the light emitting element 15 is obtained.
[0008]
Around the light emitting element 15 and its surroundings, a liquid phosphor 19 for converting the blue to ultraviolet light wavelength (350 to 400 nm) emitted from the light emitting element 15 into visible light such as white (400 to 800 nm), The light emitting element 15 is provided to be sealed. Thereby, the light of the light emitting element 15 can be converted into visible light.
[0009]
This light-emitting device is used to emit visible light by driving the light-emitting element 15 by a drive current supplied from an external electric circuit. The applications are various indicators, optical sensors, displays, photocouplers, backlights, optical printer heads, and the like.
[0010]
In recent years, this light-emitting device has been used for illumination, and a light-emitting device with higher characteristics in terms of high luminance and heat dissipation is required. Further, when used for illumination, extending the life of the light emitting device is a particularly important problem.
[0011]
Therefore, recently, a configuration for improving the light emission luminance of the light emitting device has been considered, and the frame body 14 is often made of a material having higher reflectance. For example, the frame 14 is made of a highly reflective metal such as Ag or aluminum (Al), or the metal is deposited on the surface of the frame 14 to efficiently package light emitted from the light emitting element 15. It has been proposed to radiate 11 out.
[0012]
[Patent Document 1]
JP 2002-344029 A [0013]
[Problems to be solved by the invention]
However, in the conventional package 11, when the light of the light emitting element 15 is short wavelength light including ultraviolet light (blue to ultraviolet light having a wavelength of about 350 to 400 nm), the structure of the epoxy resin adhesive 16 is ultraviolet. There was a problem of deterioration due to light. Then, as time passes, the deterioration of the tissue progresses, the frame 14 is peeled off from the base 12, and the liquid phosphor 19 leaks from the gap, so that the light of the light emitting element 15 cannot be converted into visible light. There was a point.
[0014]
Therefore, in the conventional package 11 configured to convert short-wavelength light into visible light by the liquid phosphor 19 using the light emitting element 15 that emits short-wavelength light including ultraviolet light, epoxy resin adhesion by ultraviolet light is performed. There was a problem that the reliability of the light emission was lowered due to the deterioration of the agent 16. In the future, when used in applications such as lighting, the reliability of light emission is an important issue. Even for such a light emitting device that converts ultraviolet light into visible light, sufficient light emission reliability and stable light emission characteristics are required.
[0015]
Therefore, the present invention has been completed in view of such conventional problems, and an object thereof is to provide a substrate and a frame body in a light emitting device of a type that converts short-wavelength light including ultraviolet light into visible light. It is an object of the present invention to provide a package and a light emitting device with excellent reliability and stable light emitting characteristics, which can prevent deterioration of a resin adhesive to be bonded and prevent a liquid phosphor from leaking over a long period of time.
[0016]
[Means for Solving the Problems]
The present invention is made of ceramics and surrounds a substrate on which a light emitting element that generates ultraviolet light is mounted and an area on which the light emitting element is mounted, and is bonded to the upper surface of the substrate by an acrylic resin adhesive And a metal frame having a lower surface, and the acrylic resin adhesive contains metal particles.
[0017]
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 1 according to the present invention. Reference numeral 2 denotes a base body, 4 denotes a frame, and a package 1 for mainly accommodating a light emitting element 5 is constituted by these. Yes.
[0018]
The package of the present invention surrounds the mounting portion 2a at the outer peripheral portion of the upper surface of the base 2 and the base 2 made of ceramics having the mounting portion 2a on which the light emitting element 5 that emits light including ultraviolet light is mounted at the center of the upper surface. In this way, the lower surface is bonded with the acrylic resin adhesive 6 and the metal frame body 4 is inclined so that the inner peripheral surface spreads outward toward the upper side, and the liquid phosphor 9 covering the light emitting element 5 is provided. is doing.
[0019]
The substrate 2 in the present invention is a rectangular flat plate made of ceramics such as an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, and a glass ceramic, and supports the light emitting element 5. It has a mounting portion 2a for mounting the light emitting element 5 at the center of the upper surface thereof.
[0020]
The substrate 2 is covered with a wiring conductor 3 made of a metallized layer led out from the mounting portion 2a and the periphery to the lower surface. The wiring conductor 3 is made of a metallized layer of metal powder such as W, Mo, Cu, and Ag, and functions as a conductive path for electrically connecting the light emitting element 5 accommodated in the package 1 to the outside. A light emitting element 5 such as an LED or LD is fixed to the mounting portion 2a with a conductive bonding material such as an Au—Si (silicon) alloy or Ag-epoxy resin, and the wiring conductor 3 around the mounting portion 2a is attached to the wiring conductor 3 around the mounting portion 2a. The electrodes of the light emitting element 5 are electrically connected via bonding wires.
[0021]
It should be noted that a metal having excellent corrosion resistance, such as Ni or Au, should be deposited on the exposed surface of the wiring conductor 3 to a thickness of about 1 to 20 μm, and effectively prevent the wiring conductor 3 from being oxidatively corroded. In addition, the connection between the wiring conductor 3 and the light emitting element 5 and the connection between the wiring conductor 3 and the bonding wire can be strengthened. Therefore, a Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited on the exposed surface of the wiring conductor 3 by an electrolytic plating method or an electroless plating method. Is more preferable.
[0022]
Furthermore, the thermal conductivity of the substrate 2 is preferably 10 W / m · K or more, and if it is less than 10 W / m · K, the surface temperature of the light emitting element 5 is 100 ° C. or more when a driving current of 50 mA or more is input to the light emitting element 5. Thus, it is difficult not only to shorten the life of the light emitting element 5 but also to increase the light output of the light emitting element 5.
[0023]
The frame 4 made of metal is preferably made of a metal such as Al, Ag, Au, Pt, Ti, Cr, or Cu, an alloy containing one or more of these, stainless steel, or the like. Can be reflected with high reflectance, and a light-emitting device with high luminance can be manufactured. Further, even if the frame 4 is made of an Fe—Ni alloy, Fe—Ni—Co alloy, or the like, and a metal layer having a high reflectance such as Al, Ag, Au, Pt, Ti, Cr, Cu is formed on the surface thereof. Good. Further, when the frame 4 is made of a metal that is easily discolored by oxidation of Ag, Cu or the like, or a metal layer that is easily discolored by oxidation of Ag, Cu or the like is formed, a transparent resin layer or a transparent resin is formed on the surface. A sheet may be applied.
[0024]
In the present invention, the acrylic resin adhesive 6 preferably contains metal particles such as Ag and Pt. In this case, the heat dissipation of the acrylic resin adhesive 6 is improved, and the heat of the light emitting element 5 is increased. It is possible to dissipate efficiently to the outside, and it is possible to prevent the temperature of the light emitting element 5 from rising and always operate the light emitting element 5 normally and stably. The content rate of the metal particles contained in the acrylic resin adhesive 6 is preferably 85 to 93% by weight, and thereby the heat dissipation becomes larger. If it is less than 85% by weight, the heat dissipation of the acrylic resin adhesive 6 tends to decrease, and if it exceeds 93% by weight, the adhesive strength tends to decrease.
[0025]
In the present invention, it is preferable that only the outer peripheral portion of the lower surface of the frame body 4 is bonded to the base body 2 over the entire periphery. Thereby, it can prevent that the light containing the ultraviolet light of the light emitting element 5 is directly irradiated to the acrylic resin adhesive 6, and can prevent the deterioration of the acrylic resin adhesive 6 by ultraviolet light more effectively.
[0026]
In addition, the frame 4 has an inner peripheral portion of the lower surface that protrudes over the entire circumference and an outer peripheral portion that forms a stepped portion over the entire periphery, and the acrylic resin adhesive 6 is accumulated in the stepped portion. It may be adhered to the substrate 2. Further, the lower surface and the side surface of the frame body 4 have a chamfered portion such as a flat shape or a curved surface over the entire circumference, and the acrylic resin adhesive 6 is adhered to the base 2 so that the chamfered portion is accumulated in the chamfered portion. It may be.
[0027]
The frame 4 has a through hole 4a having a circular or square cross-sectional shape for accommodating the light emitting element 5 in the center thereof, and the light emitting element 5 is accommodated in the through hole 4a and mounted. It is mounted on the part 2a. The inner peripheral surface of the through hole 4a (frame body 4) preferably has an arithmetic average roughness Ra of 0.004 to 4 [mu] m, whereby the light of the light emitting element 5 is favorably reflected by the inner peripheral surface of the through hole 4a. Can be made. If Ra exceeds 4 μm, it becomes difficult to uniformly reflect the light emitted from the light emitting element 5 accommodated in the through hole 4a, and the intensity of the reflected light tends to be biased. If it is less than 0.004 μm, it tends to be difficult to form such a surface stably and efficiently.
[0028]
Further, a Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited on the inner peripheral surface of the through hole 4a by an electrolytic plating method or an electroless plating method. Well, the corrosion resistance of the frame 4 is improved.
[0029]
Further, the through hole 4a preferably has a circular cross-sectional shape, and the light emitted from the light emitting element 5 accommodated in the through hole 4a is uniformly reflected by the inner peripheral surface of the through hole 4a so as to be external. Can emit very uniformly.
[0030]
Thus, in the package 1 of the present invention, the light emitting element 5 is mounted on the mounting portion 2a of the base 2 and the electrode of the light emitting element 5 and the wiring conductor 3 are electrically connected via the bonding wires. A liquid phosphor 9 is provided so as to cover 5, and a transparent member 8 such as a transparent resin is provided thereon to form a light emitting device. The transparent member 8 may be a transparent resin such as a silicone resin that covers the light emitting element 5. The transparent member 8 is made of glass, sapphire, or the like that is bonded to the upper surface of the frame 4 with a resin adhesive or the like. The light lid 7 may be used.
[0031]
It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present invention.
[0032]
【The invention's effect】
The light emitting element storage package of the present invention has a base made of ceramics having a mounting portion on which a light emitting element that emits light including ultraviolet light is mounted at the center of the upper surface, and an outer peripheral portion of the upper surface of the base that surrounds the mounting portion. The lower surface is bonded with an acrylic resin adhesive, the inner peripheral surface is inclined so that the outer surface spreads outward, and the liquid phosphor covering the light emitting element is provided. The base and the frame are joined together via an acrylic resin adhesive that is not easily deteriorated by ultraviolet light, thereby preventing the liquid phosphor provided inside the frame from leaking to the outside. it can. As a result, a light-emitting device with high emission reliability and stable emission characteristics can be manufactured.
[0033]
In the light emitting element storage package of the present invention, preferably, the acrylic resin adhesive contains metal particles, so that the heat dissipation of the acrylic resin adhesive is good, and heat is efficiently generated even if the light emitting element generates heat. The light emitting element can be diffused to the outside well, and the temperature of the light emitting element can be prevented from rising, so that the light emitting element can always operate normally and stably.
[0034]
In the light emitting element storage package according to the present invention, preferably, only the outer peripheral portion of the lower surface of the frame body is bonded to the substrate over the entire periphery, so that light including ultraviolet light of the light emitting element is directly irradiated to the acrylic resin adhesive. This can prevent the deterioration of the acrylic resin adhesive due to ultraviolet light more effectively.
[0035]
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 a mounting portion, and a transparent member that covers the light-emitting element, so that light having a short wavelength including ultraviolet light can be obtained. In the type of light-emitting device that converts light into visible light, the light-emitting device has high light-emission reliability and stable light-emitting characteristics.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of an embodiment of a light emitting element storage package according to the present invention.
FIG. 2 is a cross-sectional view of a conventional light emitting element storage package.
[Explanation of symbols]
1: Light-emitting element storage package 2: Base 2a: Mounting portion 4: Frame 5: Light-emitting element 6: Acrylic resin adhesive 8: Transparent member 9: Phosphor

Claims (2)

A substrate made of ceramics and mounted with a light emitting element that generates ultraviolet light;
A metal frame surrounding a region of the substrate on which the light emitting element is mounted and having a lower surface joined to the upper surface of the substrate by an acrylic resin adhesive;
A package for housing a light emitting element, wherein the acrylic resin adhesive contains metal particles . The light emitting element storage package according to claim 1;
A light-emitting element mounted on the base of the light-emitting element storage package and generating ultraviolet light; and
A light emitting device comprising: a transparent member that covers the light emitting element.

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