JP2014165468A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high quality light-emitting device by suppressing peeling between a sealing resin and an aperture inner edge of a resin package recess.SOLUTION: A light-emitting device includes a light-emitting element, a lead frame on which the light-emitting element is mounted, a resin package including a recess for holding the lead frame and housing the light-emitting element, and a sealing resin filling the recess. The side face of the recess has a first sidewall forming an aperture of the recess, a protrusion provided separately from the first sidewall, a second sidewall forming a part of the protrusion, and a notch formed by partially cutting the protrusion, in order from the outside, and the resin package is exposed at the lower part of the notch in the bottom of the recess.

Description

  The present invention relates to a light emitting device.

  As a light emitting device using a light emitting element such as a light emitting diode, a light emitting device including a resin package for protecting the light emitting element is known. A recess is formed in the resin package, and after the light emitting element is mounted therein, a light-transmitting sealing material is filled in the recess to protect the light emitting element from the external environment.

The resin package is formed of an electrically insulating resin suitable for protecting the light emitting element electrically and mechanically. For example, a nylon resin such as polyphthalamide or polyamide, a liquid crystal polymer, or an epoxy resin is preferable. It is.
As the sealing material, a material that is translucent and has good adhesion to the resin package is selected. Generally, epoxy resin or silicone resin is used. Along with this trend, a silicone resin that hardly deteriorates by light or heat is increasingly used as a sealing member.

However, the silicone resin is excellent in translucency and durability, but has a problem of poor adhesion to the resin package. In other words, when silicone resin is used as the sealing material, there is a risk of peeling starting from the inner edge of the opening of the recess and propagating into the recess due to mechanical or thermal stress between the resin package and the sealing material. To increase. In the worst case, the sealing resin may be completely separated from the resin package.
In order to solve this problem, it is known that a wall portion is provided in the concave portion of the resin package, and an annular groove portion is provided between the wall portion and the inner wall of the concave portion. The sealing material fills not only the recesses of the resin package but also the grooves, and functions as an anchor ring.

JP-T-2006-516816 JP 2008-41917 A

  Separation between the inner edge of the opening of the recess of the resin package and the sealing material causes not only the starting point of separation of the entire sealing material but also intrusion of moisture and impurities into the light emitting device. If moisture, impurities, or the like entering from the peeled portion reach the bottom surface of the recess, it may cause a failure of the light emitting device.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a light-emitting device with high reliability and long life by suppressing peeling between the sealing resin and the opening inner edge of the resin package recess.

  A light emitting device according to the present invention includes a light emitting element, a lead frame on which the light emitting element is placed, a resin package having a recess for holding the lead frame and housing the light emitting element, and the recess filled. A side surface of the concave portion, in order from the outside, a first side wall forming an opening of the concave portion, and a protrusion provided apart from the first side wall And a second side wall forming a part of the protruding portion, and a notched portion in which the protruding portion is partially cut out, and the bottom surface of the recessed portion is a lower portion of the notched portion. And the resin package is exposed.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress peeling with sealing resin and the opening inner edge of a resin package recessed part, and to provide a high quality light-emitting device.

It is a schematic perspective view for demonstrating the light-emitting device of this invention. It is a schematic top view for demonstrating the light-emitting device of this invention. It is a schematic sectional drawing of the AA line of the light-emitting device of FIG. It is a schematic sectional drawing of the BB line of the light-emitting device of FIG.

  The light-emitting device of the present invention includes, for example, a light-emitting element 1, a lead frame 1a on which the light-emitting element is placed, and a recess that holds the lead frame and stores the light-emitting element, as in the light-emitting device 100 shown in FIG. A resin package 4 and a sealing resin filled in the recess, and the side surface of the recess is, in order from the outside, a first side wall 41 that forms the opening of the recess, and the first side wall. And a projecting portion 43 provided, a second side wall 42 that forms a part of the projecting portion, and a notched portion 4a, 4b, 4c in which the projecting portion is partially cut out, The bottom surface of the recess is characterized in that the resin package 4 is exposed at the lower part of the notch.

  Below, each component is explained in full detail.

<Light emitting element>
The light emitting element is usually a semiconductor light emitting element, and any element may be used as long as it is a so-called light emitting diode element. At least one light emitting element is mounted.

  In the light-emitting device of the present invention, one or more light-emitting elements are mounted. However, a plurality of light-emitting elements that emit different colors may be mounted. The color reproducibility can be improved by combining a light emitting element that emits red or red light.

The light emitting element may be any element that is a so-called light emitting diode. Moreover, the thing of arbitrary wavelengths can be selected according to a use. For example, as a light emitting element of blue (light having a wavelength of 430 nm to 490 nm) and green (light having a wavelength of 490 nm to 570 nm), ZnSe, a nitride-based semiconductor (In _X Al _Y Ga _1-XY N, 0 ≦ X, 0 ≦ Y, X + Y <1), GaP, or the like can be used. As a red light emitting element (light having a wavelength of 620 nm to 750 nm), GaAlAs, AlInGaP, or the like can be used.

  The light emitting element is mounted on a lead frame described later, and a joining member is used for this purpose. For example, in the case of a light emitting element having blue and green light emission and formed by growing a nitride semiconductor on a sapphire substrate, an epoxy resin, silicone or the like can be used. In consideration of deterioration from light and heat from the light emitting element, the back surface of the light emitting element may be plated with Al, without using resin, solder such as Au—Sn eutectic, low melting point metal, etc. A material may be used. Furthermore, in the case of a light emitting element made of GaAs or the like and having electrodes formed on both sides thereof, such as a light emitting element that emits red light, die bonding may be performed using a conductive paste such as silver, gold, or palladium.

  Note that the light-emitting element is usually face-up mounted, that is, a pair of electrodes is formed on the same surface side with respect to the substrate (or semiconductor layer) of the light-emitting element, and the surface on which the electrodes are formed is used as a light emitting surface. It is mounted on a light-emitting device by a type that is mounted facing or by flip chip mounting.

  In the light emitting device of the present invention, a protective element may be mounted in addition to the light emitting element. The number of protective elements may be one, or two or more. Here, the protective element is not particularly limited, and may be any known element mounted on the light emitting device. Specifically, overheating, overvoltage, overcurrent, a protection circuit, an electrostatic protection element, etc. are mentioned. The part to be mounted may be in the opening and in the vicinity of the light emitting element, but may be partly or wholly embedded in the resin package.

<Resin package>
The resin package is a member for mounting the light emitting element, and is molded of resin. The resin package may be molded using any resin as long as this function can be ensured. For example, a thermoplastic resin, a thermosetting resin, etc. are mentioned. Specifically, polyimide (PI), polyamide (PA), polycarbonate resin, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), ABS resin, epoxy resin, phenol resin, acrylic resin, PBT resin, packaging materials in this field Resin such as resins (for example, resins described in JP2011-256326A and JP2011-177893A), ceramics, and the like. Moreover, you may mix and use various dyes or pigments for these materials as a coloring agent or a light-diffusion agent. Examples of the colorant include Cr ₂ O ₃ , MnO ₂ , Fe ₂ O ₃ , and carbon black. Examples of the light diffusing agent include calcium carbonate, aluminum oxide, and titanium oxide. As a result, light emitted from the light emitting element absorbed by the package can be minimized, or a package of various colors such as a white package or a black package with high reflectance can be configured. Two or more kinds of resins may be used as necessary.

  A resin package is usually filled with a light-transmitting resin in a recess, and therefore, considering the adhesiveness between the package and the sealing resin when affected by heat generated from a light emitting element, these heat It is preferable to select one having a small difference in expansion coefficient.

  The size and shape of the resin package are not particularly limited, and examples of the outer shape in plan view include a circle, an ellipse, a triangle, a quadrangle, a polygon, and a shape similar to these. The size can be appropriately adjusted depending on the size of the light emitting element to be used and the number of light emitting elements to be mounted.

(Side wall)
The side surface of the concave portion of the resin package 4 includes a first side wall 41 that forms the opening of the concave portion, a protruding portion 43 that is spaced from the first side wall, and a first side that forms a part of the protruding portion 43. 2 side walls 42 and cutout portions 4a, 4b, 4c in which the protruding portions 43 are partially cut out.

  The protrusion is provided at the inner edge of the opening to prevent light from the light emitting element from being directly irradiated. The peeling between the inner edge of the opening of the recess of the resin package and the sealing resin is caused by the direct light from the light emitting element being applied to the inner edge of the opening and the adhesiveness between the inner edge of the opening and the sealing resin being lowered. Therefore, the occurrence of peeling can be suppressed by providing the protruding portion.

  In order to prevent direct irradiation from the light emitting element, the protrusion height of the protrusion is preferably high. It is preferable to form so as to reliably block a line connecting the end of the light emitting surface of the light emitting element and the opening. However, if the protruding portion is provided high, when the sealing resin is potted into the recess, the protruding portion becomes a weir, and the sealing resin potted in the recess has the resin as the first side wall and the second side wall. It becomes difficult to fill the space between the projections. Therefore, by providing a notch in the protrusion, the sealing resin can easily flow between the first side wall and the second side wall (protrusion), and the sealing resin can be filled evenly. Become. The effect can be obtained by providing only one notch, but it is preferable to provide two or more spaced apart so that the sealing resin can flow more easily.

  Since the notch is provided for ease of flow when potting the sealing resin, if the resin is smoothly filled between the first side wall and the second side wall (projection), The shape of the notch is not particularly limited.

  In order to facilitate the flow of the sealing resin, it is better that the notch width is larger, but if the lead frame is exposed at the lower part of the notch, peeling of the sealing resin described later leads Since there is a risk of reaching the frame, the notch width of the notch is preferably the same as or smaller than the width of the resin package exposed at the bottom. In consideration of the ease of molding of the resin package, the notch portion is preferably perpendicular or wide toward the opening direction of the recess.

  For example, in FIG. 1, there is a groove that is continuous in an annular shape when viewed from the opening direction of the recess between the first side wall and the protrusion, and the height of the notch from the bottom of the opening is the groove. It is provided to be the same height. By providing them at the same height, the sealing resin flows smoothly, and it is difficult for air to be enclosed in the sealing resin.

(Bottom)
The shape of the bottom surface of the opening of the resin package is not particularly limited, and may be any of a circle, an ellipse, a triangle, a quadrangle, or a shape similar to these. The size can be appropriately adjusted depending on the size of the light emitting element to be used and the number of light emitting elements to be mounted.

  The lead frame is exposed at the bottom surface of the recess of the resin package. The lead frame is embedded in the resin package with the surface on which the light emitting element is placed exposed. The lead frame is formed to be flush with the resin package at the bottom of the recess. In the light emitting device of the present invention, the resin package is exposed on the bottom surface corresponding to the lower portion of the notch. In other words, no notch is provided in the upper part of the side surface in contact with the lead frame.

  As described above, the protruding portion is provided in order to suppress the occurrence of peeling between the inner edge of the opening and the sealing resin. However, by providing the notch in the protruding portion, the first side surface corresponding to the notch is likely to be directly irradiated with light from the light emitting element. For this reason, it is preferable to provide a notch part in the position away from the light emitting element as much as possible. When there are a plurality of light-emitting elements having different wavelengths, peeling of the sealing resin is likely to occur in the vicinity of the short-wavelength element. Therefore, the notch is preferably provided at a position away from the light-emitting element having the shortest wavelength. . For example, in the case where light emitting elements having different emission colors of red, green, and blue are mounted, the notch is preferably provided at a position farther from the blue light emitting element having the shortest emission wavelength. .

  Here, even if the sealing resin is peeled off from the side surface, the light emitting device does not immediately turn off. However, when the peeling from the side surface reaches the lead frame on the bottom surface, since the light emitting element is placed on the lead frame, the light emitting element may be peeled off from the bottom surface together with the sealing resin. In particular, since the conductive wire connecting the light emitting element and the lead frame is often bonded to the end portion of the bottom surface of the recess rather than the light emitting element, it is more easily affected by the peeling of the sealing resin, If the wire breakage is caused by the peeling of the sealing resin, the light emitting element is immediately turned off.

  In the light emitting device of the present invention, the bottom surface of the resin package recess is configured such that the resin package is exposed at the lower portion of the notch. The progress of peeling is not in the horizontal direction without the notch, but in the vertical direction from the notch, so even if the peeling progresses and reaches the bottom, the sealing resin and the resin package are in close contact with each other Since the property is stronger than the adhesion between the sealing resin and the lead frame, peeling can be prevented from reaching the lead frame.

  In addition, when the silver plating described later is applied to the lead frame, there is a possibility that sulfur component or the like enters through the peeling gap and silver sulfidation occurs. However, in the light emitting device of the present invention, the notch that is most likely to peel off is used. Since the lead frame is not exposed at the bottom of the part, silver sulfidation can be suppressed.

<Lead frame>
A lead frame is partially embedded in the resin package of the present invention. The lead frame is a member for mounting the light emitting element. Further, it also serves as an electrode and lead terminal that are electrically connected to the light emitting element. For this purpose, the lead frame is exposed on the bottom surface of the recess of the resin package in order to place the light emitting element on the other side of the resin package and fix the light emitting element, and to make an electrical connection. The other part protrudes out of the package. By exposing a part of the surface of the bottom surface of the lead frame, light from the light emitting element can be reflected and efficiently extracted in the front direction.

  A through hole may be formed in the lead frame in the thickness direction. Since the bottom surface of the resin package is exposed from the through hole, forming the through hole in the lead frame reduces the area where the sealing resin comes into contact with the lead frame when the concave resin is filled with the sealing resin. The area in contact with the package material will increase. Since the adhesiveness between the sealing resin and the resin package is stronger than the adhesiveness between the lead frame and the resin package, the fixing force between the resin package and the sealing resin can be increased.

  In addition, the lead frame may be formed with a through hole in the thickness direction or a part of the lead frame at a portion in contact with the second side wall. Not only the area where the sealing resin and the resin package material come into contact with each other when the recess is filled with the sealing resin, but also the resin package is exposed on the bottom surface. it can.

  In general, two or more lead frames are provided in one light-emitting device, and the number of light-emitting elements may be one or more, or may be two or more times the number of light-emitting elements. For example, when three light-emitting elements are mounted, one light-emitting element is placed on one lead frame, and these light-emitting elements are placed on a lead frame on which they are placed, and in a different lead frame. , Each electrically connected. The plurality of lead frames are substantially electrically separated and disposed in the package other than the electrical connection with the electrodes of the light emitting element described above.

  The lead frame only needs to be substantially plate-shaped, and may be corrugated plate-shaped or plate-shaped having irregularities. The material is not particularly limited and may be any material that can supply appropriate power to the light emitting element. Moreover, it is preferable to form with a material with comparatively large thermal conductivity. By forming with such a material, heat generated in the light emitting element can be efficiently released. For example, a material having a thermal conductivity of about 200 W / (m · K) or more, a material having a relatively large mechanical strength, or a material that can be easily punched or etched is preferable. Specific examples include metals such as copper, aluminum, gold, silver, tungsten, iron and nickel, and alloys such as iron-nickel alloys and phosphor bronze. Further, the surface of the lead frame is preferably subjected to reflection plating (for example, using silver or a silver alloy, Ni / Pd / Au, etc.) in order to efficiently extract light from the mounted light emitting element. The size, thickness, shape, etc. of the lead frame can be appropriately adjusted in consideration of the size, shape, etc. of the light emitting device to be obtained.

  The portion of the lead frame that extends outside the package (that is, the lead terminal) has a shape and size that takes into consideration the heat dissipation of the light emitting element mounted on the light emitting device and the usage of the light emitting device (arrangement space, location, etc.) The thickness and the like can be adjusted as appropriate. In addition, the lead terminal can be appropriately bent and deformed according to a usage mode such as a positional relationship with another electronic device.

<Sealing resin>
In the light emitting device of the present invention, a sealing resin is filled in the resin package recess in which the light emitting element is placed. The sealing resin is a member that seals a part of the light emitting element, the conductive wire, and the lead frame and protects them from dust, moisture, external force, and the like. The base material of the light-transmitting resin is preferably formed of a material that can transmit light emitted from the light-emitting element (preferably a transmittance of 70% or more).

  Specifically, an addition or condensation type silicone resin, epoxy resin, phenol resin, polycarbonate resin, acrylic resin, ABS resin, polybutylene terephthalate resin, polyphthalamide resin, polyphenylene sulfide resin, liquid crystal polymer, or these resins Although the hybrid resin containing 1 or more types is mentioned, Silicone resin is particularly preferable.

The sealing resin may contain a diffusing agent or a fluorescent material. The diffusing agent diffuses light and can reduce the directivity from the light emitting element and increase the viewing angle. The fluorescent substance converts light from the light emitting element, and can convert the wavelength of light emitted from the light emitting element to the outside of the package. When the light from the light-emitting element is high-energy short-wavelength visible light, nitrogen-containing CaO—Al ₂ O activated with an organic phosphor, a perylene derivative, ZnCdS: Cu, YAG: Ce, Eu and / or Cr Various inorganic phosphors such as _3- SiO ₂ are suitably used. In the present invention, when white light is obtained, particularly when a YAG: Ce phosphor is used, light from the blue light-emitting element and a yellow color which is a complementary color by partially absorbing the light can be emitted depending on the content thereof. The system can be formed relatively easily and reliably. Similarly, when a nitrogen-containing CaO—Al ₂ O ₃ —SiO ₂ phosphor activated with Eu and / or Cr is used, light from the blue light emitting element and a part of the light are absorbed depending on the content. Thus, a red color which is a complementary color can emit light, and a white color can be formed relatively easily and with high reliability. In addition, color unevenness can be reduced by completely precipitating the phosphor and removing bubbles. Note that two or more kinds of sealing resins may be used as necessary.

(Wire)
In the light-emitting device of the present invention, the pair of electrodes formed on the light-emitting element is electrically connected to the lead frame and / or the electrode of the adjacent light-emitting element by a wire in order to supply power to the light-emitting element. . The material and diameter of the wire are not particularly limited, and those commonly used in the field can be used. In particular, it is preferable that the ohmic property with the electrode of the light emitting element is good, the mechanical connectivity is good, or the electrical conductivity and thermal conductivity are good.

  As the wire, for example, a wire using a metal such as gold, copper, platinum, aluminum, silver or an alloy thereof, a wire coated with silver or a silver alloy, or the like can be used. Especially, as a material with a high reflectance, silver, copper, lead, aluminum, platinum, or these alloys are preferable, and silver or a silver alloy is more preferable. For example, as a commercial product, a wire (trade name: SEA, manufactured by Tanaka Kikinzoku Co., Ltd.) containing 87.7% by volume of silver, 8.7% by volume of gold, and 3.6% by volume of palladium can be given.

Although the diameter of a wire is not specifically limited, About 10 micrometers-70 micrometers are mentioned, About 15-50 micrometers is preferable, About 18-30 micrometers (for example, about 25 micrometers) is more preferable. The thermal conductivity of the wire preferably ^{0.01cal / S · cm 2 · ℃} / than about cm further ^{0.5cal / S · cm 2 · ℃} / cm or higher order is more preferable.

Embodiments of the light emitting device according to the present invention will be described below in detail with reference to the drawings.
FIG. 2 is a schematic top view of the light emitting device 100 according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the light emitting device 100 in FIG. 2 along the AA direction. FIG. 4 is a schematic cross-sectional view along the BB direction of the semiconductor device 100 in FIG. In FIG. 2 and FIG. 3, wires are omitted.

  As shown in FIGS. 2 to 4, the light-emitting device of this embodiment includes three light-emitting elements 1, 2, and 3 having different emission wavelengths and a resin package 4 that includes a recess that houses the light-emitting elements. The light emitting elements 1, 2, and 3 are a blue light emitting element 1, a green light emitting element 2, and a red light emitting element 3, respectively, and are arranged linearly in this order.

  The blue light-emitting element 1 and the green light-emitting element 2 are formed by a structure in which a GaN-based semiconductor layer is stacked on a sapphire substrate, and the emission wavelengths thereof are around 470 nm and 520 nm, respectively. The red light emitting element 3 is formed by a structure in which an InAlGaP semiconductor layer is bonded to a GaP substrate, and the light emission wavelength is around 620 nm. Three pairs of lead frames 1a, 1b, 2a, 2b, 3a, and 3b corresponding to the three light emitting elements to be mounted are exposed on the bottom surface in the concave portion of the resin package.

  The light emitting device 100 of this example has a shape in which the top surface is 3.3 mm long and 3.0 mm wide, and the height from the bottom surface to the top surface at the package end is 0.8 mm.

  The opening of the resin package recess is provided at substantially the center of the upper surface of the resin package, and the depth from the upper surface of the resin package 4 to the bottom of the opening is 0.45 mm. The outer periphery of the first side wall 41 has a rectangular shape with rounded corners of 2.25 mm in length and 2.55 mm in width, and the outer periphery of the second side wall 42 has corners of 2.05 mm in length and 2.35 mm in width. The second side wall 42 is inclined so as to spread at an angle of 80 degrees from the bottom surface toward the upper surface side.

  Rectangular lead elements 1, 2, and 3 that emit light having wavelengths of 470 nm, 520 nm, and 620 nm are respectively formed on lead frames 1 a, 2 a, and 3 a that are exposed on the bottom surface of the opening of the resin package 4. Are bonded to the negative lead frame and electrically connected to the positive and negative lead frames 1a, 1b, 2a, 2b, 3a, and 3b by Au wires having a diameter of 25 μm. A protective element is bonded to the lead frames 1b and 2b using a silver paste (not shown), and electrically connected to the lead frames 1a and 2a by Au wires. Grooves are provided on the lead frames 1b and 2b to prevent the silver paste for adhering the protective elements from flowing on the wires connecting the light emitting elements.

  The protrusion 43 has a width of 0.04 mm and is provided at a position where the height from the bottom surface to the protrusion is 0.40 mm.

In the light emitting device 100 of the present embodiment, three notches are provided. On the bottom surface of the opening, the resin package 4 is exposed under the notches 4a, 4b, and 4c. Since a total of 6 pairs of 3 lead frames are exposed at the bottom of the opening, it is possible to provide up to 6 notches between these lead frames. A notch is not provided in a region adjacent to the lead frame 1a on which the light emitting element 1 is placed.
Notches 4b and 4c are provided on the side surface close to the lead frame 3a on which the light emitting element 3 having the longest emission wavelength is placed. The notch 4a is provided at a position diagonal to the notch 4b in consideration of the fluidity of the sealing resin.

  Then, a silicone resin 5 as a sealing resin is potted in the opening. At this time, the potting is performed so that the liquid silicone resin enters between the first side wall and the second side wall through the notch provided in the protrusion 43. Thereafter, the silicone resin is cured in an oven, whereby the light emitting device 100 of the example of the present invention is obtained.

  The light emitting device of the present invention can be used for various lighting devices such as a light source for illumination, a backlight light source such as an LED display, a mobile phone, a traffic light, an illumination switch, an in-vehicle light source, an amusement, various sensors, and various indicators. it can.

100 Light-emitting devices 1, 2, 3, Light-emitting elements 1a, 1b, 2a, 2b, 3a, 3b Lead frame 4 Resin package 41 First side wall 42 Second side wall 43 Projection part 4a, 4b, 4c Notch part 5 Sealing Resin

Claims (4)

A light emitting element;
A lead frame on which the light emitting element is mounted;
A light emitting device having a resin package having a recess for holding the lead frame and accommodating the light emitting element, and a sealing resin filled in the recess,
The side surface of the recess is in order from the outside,
A first side wall forming an opening of the recess;
A protrusion provided apart from the first side wall;
A second sidewall forming part of the protrusion;
The protrusion has a notch partly cut away,
The bottom surface of the recess is
In the lower part of the notch,
The light emitting device, wherein the resin package is exposed. The light-emitting device according to claim 1, wherein two or more light-emitting elements having different emission wavelengths are placed on different lead frames. 3. The light emitting device according to claim 1 or 2, wherein three light emitting elements having blue, green, and red light emission wavelengths are arranged in a line in this order. The light emitting device according to claim 1, wherein the sealing resin is a silicone resin.

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