JP5837775B2 - Semiconductor light emitting device - Google Patents

Description

  The present invention relates to a semiconductor light emitting device including a semiconductor light emitting element such as an LED element, and more particularly to a semiconductor light emitting device in which a reflective member is provided on a light emitting surface of a mounted semiconductor light emitting element via a light transmitting member.

  In recent years, an LED element (hereinafter abbreviated as LED) is a semiconductor light emitting element, and therefore has a long life and excellent driving characteristics, is small in size, has high luminous efficiency, and has a bright emission color. It has come to be widely used for backlights and lighting. In the present invention, an LED light emitting device will be described as an example of the semiconductor light emitting device.

  Particularly in recent years, an LED light emitting device has been proposed in which the periphery of an LED is coated with a translucent resin as a translucent member, and a reflective member layer is provided on the top surface side of the coated translucent resin. (For example, Patent Document 1 and Patent Document 2)

  Hereinafter, a conventional LED light emitting device in which a reflecting member is disposed on the upper surface of the light transmitting member will be described. For ease of understanding, the drawings are partially simplified within the scope not departing from the spirit of the invention, and component names are also included in the present application. FIG. 7 is a cross-sectional view of the LED light emitting device 100 disclosed in Patent Document 1. Wiring electrodes 103a and 103b are provided on the upper surface of the circuit board 102, and the electrodes of the LED 101 mounted and fixed to the wiring electrode 103a are provided. The wire 104 is wire-bonded to the wiring electrode 103b. Further, the wiring electrodes 103a and 103b are guided to the back side of the circuit board 102 through the side surface of the circuit board 102 to form the drive electrode 103c.

  Further, the upper surface and side surfaces of the LED 101 are sealed with a translucent resin 105 (translucent member), and a reflective member 106 (light shielding layer) is provided on the upper surface of the translucent resin 105. That is, the reflecting member 106 is arranged at a position that blocks strong radiated light emitted directly above the LED 101.

  Next, the light emitting operation of the LED light emitting device 100 will be described. When a drive current is supplied to the LED 101 from the drive electrode 103c of the circuit board 102 connected to a mounting board (not shown) by soldering or the like, the LED 101 emits light. Consider a case where the reflecting member 106 is not present at this time. Even if the LED 101 emits light in the upper surface and side surface directions, the upward emitted light is extremely strong. For this reason, the LED 101 is in an extremely strong light emitting state where the area directly above the LED 101 is extremely strong and the periphery is weak, and when the LED light emitting device 100 is incorporated into the lighting device, uneven brightness occurs. That is, only the center of the LDE 101 is bright and the surroundings are dark.

  In order to solve the above problem, in the LED light emitting device 100, a reflective member 106 (light shielding layer) is provided on the translucent resin upper surface 105a of the translucent resin 105 sealing the LED 101. That is, the extremely strong radiated light directly above the LED 101 is blocked or suppressed by the reflecting member 106, and further reflected by the reflecting member 106 and radiated from the surroundings, thereby improving the uneven light distribution in which the front surface of the LED 101 becomes locally bright. doing. The reflective member 106 is made of a material that reflects light emitted from the LED 101, such as a white resin or a metal layer.

  FIG. 8 is a cross-sectional view of the LED light emitting device 200 shown in FIG. The LED light emitting device 200 includes an LED 201 flip-chip mounted on a wiring electrode (not shown) provided on an upper surface of a circuit board 202, a translucent resin 205 that seals the LED 201 so as to cover the LED 201, and a translucent resin 205. A reflection member 206 formed on the upper surface of the substrate is provided. The reflection member 206 is made of a transflective metal foil film and is formed by vapor deposition or plating. By arbitrarily setting the reflectance (or transmittance) and area of the reflecting member 206, the thickness of the translucent resin 205, and the like, it is possible to control the light emission amount and the spread angle in the front direction. For example, the directivity can be improved by adjusting the amount of transmitted light P1 transmitted through the reflecting member 206 and the optical path length of the reflected light P2 emitted in the side surface direction. This LED light emitting device 200 reduces light emission unevenness with a small number of components.

Japanese Patent Laying-Open No. 2001-257381 (FIG. 1) Japanese Patent Laying-Open No. 2004-304041 (FIG. 1)

  In the LED light emitting devices 100 and 200 described in the cited documents 1 and 2, the translucent resins 105 and 205 are strongly bonded to the circuit boards 102 and 202 and the reflecting members 106 and 206. However, as is well known, if fluorescent particles are mixed in the translucent resins 105 and 205 in order to whiten the emission color, the adhesion performance may be lowered.

  Accordingly, an object of the present invention is to solve the above-described problems. A semiconductor light-emitting element having at least a side surface and an upper surface covered with a light-transmitting member (hereinafter referred to as a fluorescent member) containing a phosphor, and the semiconductor light-emitting device. In a semiconductor light emitting device including a circuit board on which an element is mounted and a reflecting member disposed on the upper surface of the fluorescent member, an LED light emitting device in which the adhesion between the fluorescent member, the circuit board, and the reflecting member is increased is provided. is there.

In order to achieve the above object, the configuration of the LED light emitting device in the present invention is as follows.
In a semiconductor light emitting device comprising a semiconductor light emitting device having at least a side surface and an upper surface covered with a fluorescent member, a circuit board on which the semiconductor light emitting device is mounted, and a reflective member on the upper surface of the fluorescent member, A transparent member is provided in a region sandwiched between the circuit board and the reflective member , the reflective member is made of a harder material than the fluorescent member, the reflective member is attached to the fluorescent member, and the reflective member It has a groove on the upper surface of the member .

  According to the above configuration, the poor adhesion of the fluorescent member to the circuit board and the reflecting member can be compensated by the good adhesion of the transparent member provided around the fluorescent member.

  A step portion may be provided around the circuit board, and the step portion and the transparent member may be engaged with each other.

  According to the above configuration, the coupling between the circuit board and the transparent member can be further strengthened by engaging the transparent member with the step portion around the circuit board.

  According to the said structure, manufacture becomes easy by using a metal plate with good handleability or a hard resin board as a reflecting member. Furthermore, by providing a groove on the upper surface of the plate-like reflecting member, it is possible to prevent warpage caused by a difference in thermal expansion coefficient between the reflecting member and another member.

  The reflective member may be transmissive, and the reflective member may have transmissive fine openings.

According to the said structure, since emitted light exists also in the upper surface side of a reflection member by the transmittance | permeability of a reflection member, light distribution can be balanced by adjusting the transmittance | permeability and reflectance of this reflection member. If this semiconductor light-emitting device is incorporated in a lighting device, the light distribution is good and the characteristics of the lighting device are improved.
Further, in the case of a configuration in which a transmissive fine opening is provided in the reflective member, a highly reflective metal plate can be used as the reflective member, so that the transmittance and reflectance of the reflective member are adjusted with higher accuracy. be able to.

  As described above, according to the present invention, the poor adhesion of the fluorescent resin to the circuit board and the reflecting member can be compensated by the good adhesion of the transparent member provided around the fluorescent member. For this reason, it is possible to prevent the occurrence of troubles due to peeling of the bonded portion or moisture intrusion from the bonded portion.

The LED light-emitting device in 1st Embodiment of this invention is shown, (a) is sectional drawing, (b) is a top view, (c) is a side view, (d) is a bottom view. It is sectional drawing which shows the emission characteristic of the LED light-emitting device shown to Fig.1 (a). The LED light-emitting device in 2nd Embodiment of this invention is shown, (a) is sectional drawing, (b) is a top view, (c) is a side view, (d) is a bottom view. The LED light-emitting device in 3rd Embodiment of this invention is shown, (a) is sectional drawing, (b) is a top view, (c) is a side view, (d) is a bottom view. It is sectional drawing which shows the emission characteristic of the LED light-emitting device shown to Fig.4 (a). The LED light-emitting device in a reference example is shown, (a) is sectional drawing, (b) is a top view, (c) is a side view, (d) is a bottom view. It is sectional drawing of the conventional LED light-emitting device. It is sectional drawing of the conventional LED light-emitting device.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an LED light emitting device 10 according to a first embodiment of the present invention, wherein (a) is a cross-sectional view of the LED light emitting device 10, (b) is a top view of the LED light emitting device 10 shown in (a), and (c). Is a side view, and (d) is a bottom view.

  In the cross-sectional view of the LED light emitting device 10 shown in FIG. 1A, the two wiring electrodes 3a provided on the upper surface of the circuit board 2 are connected to the drive electrode 3c through the through-hole electrode 3b. The LED 1 is flip-chip mounted (hereinafter abbreviated as FC mounting) on the wiring electrode 3 a, and a step portion 2 d is provided around the circuit board 2. The upper surface and side surfaces of the LED 1 are covered with a fluorescent resin 7 (fluorescent member), and a reflective member 6 is bonded to the fluorescent resin upper surface 7 a of the fluorescent resin 7. A groove 6 a described later is provided on the upper surface of the reflecting member 6. Further, a transparent resin 5 is filled in a space around the fluorescent resin 7 and serving as a gap between the reflecting member 6 and the circuit board 2. The transparent resin 5 is bonded at the stepped portion 2d of the circuit board 2 to strengthen the peripheral portion.

Next, the whole structure of the LED light-emitting device 10 is demonstrated with reference to FIG.1 (b)-(d).
FIG. 1B is a top view of the LED light emitting device 10, and FIG. 1A corresponds to the AA cross-sectional view of FIG. In (b), the reflecting member 6 is required to have an appropriate light transmittance and an appropriate light reflectivity. For example, a white resin plate in which a reflective material such as titanium oxide is mixed in an acrylic resin or an epoxy resin, It is a metal plate or the like.

  Further, as shown in the side view of (c), the plate-like reflecting member 6 is made of a harder material than the fluorescent resin 7, and the reflecting member 6 is fixed to the fluorescent resin 7 so that the reflecting member 6 is fixed. There is a risk that warping may occur due to the difference between the coefficient of thermal expansion and the coefficient of thermal expansion of other members. Therefore, grooves 6a are formed in a grid shape on the upper surface of the reflecting member 6 in order to disperse the internal stress to be warped. Further, the periphery of the reflection member 6 and the periphery of the circuit board 2 including the cut-off portion 2d are adhered by the transparent resin 5, thereby reinforcing the fluorescent resin 7 having a reduced adhesive force. (D) is a bottom view of the LED light emitting device 10, and two drive electrodes 3 c are provided on the bottom surface of the circuit board 2.

  Next, the light emitting operation of the LED light emitting device 10 will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a light emission state of the LED light emitting device 10 shown in FIG. 1, and the configuration is the same as that of the LED light emitting device 10 of FIG. In this embodiment, the LED 1 is a blue LED, the fluorescent resin 7 is a YAG fluorescent resin that kneads YAG in a silicone resin and converts the blue light emission of the LED 1 to yellow light, and the LED light emitting device 10 emits white light. An example of the apparatus will be described.

  In the LED light emitting device 10, the LED 1 emits blue light Pb by supplying a drive current to the drive electrode 3c. A part of the blue light Pb is transmitted through the semi-transmissive reflecting member 6 and is emitted as indicated by a solid line with an arrow. Another part of the blue light is reflected by the reflecting member 6, the circuit board 2, etc., passes through the transparent resin 5, and is emitted in the side surface direction of the LED light emitting device 10. Further, a part of the yellow light Py indicated by the dotted line with an arrow obtained by converting the wavelength of the emitted light of the LED 1 by the YAG particles dispersed in the fluorescent resin 7 passes through the reflecting member 6 and is emitted. Further, another part of the yellow light Py passes through the transparent resin 5 while being reflected by the reflecting member 6 and the circuit board 2 and is emitted in the side surface direction of the LED light emitting device 10. Note that blue light Pb and yellow light Py emitted from the side surface of the LED light emitting device 10 without being reflected are not shown. As a result, a blue light Pb and a yellow light Py are distributed over a wide range including the side surface direction from the upper surface of the LED light emitting device 10, and a semiconductor light emitting device that emits white light over a wide range by the combined light is obtained.

(Second Embodiment)
Next, the LED light-emitting device 20 in 2nd Embodiment of this invention is demonstrated with FIG. FIG. 3 shows the LED light emitting device 20, (a) is a cross-sectional view of the LED light emitting device 20, (b) is a top view of the LED light emitting device 20 shown in (a), (c) is a side view, and (d) is a side view. A bottom view is shown.

  In the cross-sectional view of the LED light emitting device 20 shown in FIG. 3A, the difference from the LED light emitting device 10 of the first embodiment shown in FIG. While the resin 7 is filled between the circuit board 2 and the reflecting member 6, the fluorescent resin 7 covers the periphery of the LED 1 with a certain thickness in the LED light emitting device 20, and the transparent resin 5 is on the outside thereof. That is, a space including the gap between the fluorescent resin 7 and the reflective layer 6 is filled. 3B to 3D showing the entire configuration of the LED light emitting device 20 are basically the same as FIGS. 1B to 1D showing the overall configuration of the LED light emitting device 10 in the first embodiment. The overlapping description is omitted.

  Compared with the LED light-emitting device 10, the LED light-emitting device 20 has almost all the adhesion between the circuit board 2 and the reflecting member 6 made of the transparent resin 5, so that the adhesive force between the circuit board 2 and the reflecting member 6 is extremely strong. In the present embodiment, the stepped portion 2d is provided on the circuit board 2 and engaged and bonded. However, sufficient strength can be obtained without performing the engaged and bonded, and may be omitted if necessary.

(Third embodiment)
Next, an LED light emitting device 30 according to a third embodiment of the present invention will be described with reference to FIG. FIG. 4 shows the LED light emitting device 30, (a) is a cross-sectional view of the LED light emitting device 30, (b) is a top view of the LED light emitting device 30 shown in (a), (c) is a side view, and (d) is a side view. A bottom view is shown.

  4A is different from the LED light emitting device 10 of the first embodiment shown in FIG. 1A in that the reflecting member 6 in the LED light emitting device 10 is semi-transmissive. In contrast, the reflective member 46 of the LED light emitting device 30 uses a metal plate, and the reflective member 46 is provided with a plurality of fine openings 46a in order to give a predetermined transparency. .

Next, the overall configuration of the LED light emitting device 30 will be described with reference to FIGS.
FIG. 4B is a top view of the LED light emitting device 30, and FIG. 4A corresponds to the AA cross-sectional view of FIG. In (b), the reflecting member 46 constitutes a semi-transmissive reflecting member by the complete reflection by the metal plate and the translucency of the plurality of fine openings 46a.
4 (c) and 4 (d) are the same as FIGS. 1 (c) and 1 (d) except for the configuration of the reflecting member, and thus a duplicate description is omitted.

  Next, the light emitting operation of the LED light emitting device 30 will be described with reference to FIG. FIG. 5 is a cross-sectional view showing a light emission state of the LED light emitting device 30 shown in FIG. 4, and the configuration is the same as that of the LED light emitting device 10 of FIG. Also, in this embodiment, a case where a blue LED is used as the LED 1, a YAG fluorescent resin that converts blue light emitted from the LED 1 into yellow light is used as the fluorescent resin 7, and white light is emitted as the LED light emitting device 30 will be described.

  In the LED light emitting device 30, the drive current is supplied to the drive electrode 3c, so that the LED 1 emits blue light Pb. A part of the blue light Pb is transmitted through the fine opening 46a of the reflecting member 46 as shown by a solid line with an arrow, and another part is reflected by the reflecting member 46 or the circuit board 2 and passes through the transparent resin 5. Then, the light is emitted in the side surface direction of the LED light emitting device 30. In addition, a part of the yellow light Py indicated by the dotted line with an arrow obtained by converting the wavelength of the blue emitted light of the LED 1 by the YAG particles of the fluorescent resin 7 passes through the fine opening 46a of the reflecting member 46 to be emitted, and another yellow light. A part of Py is reflected by the reflecting member 6, the circuit board 2, etc., passes through the transparent resin 5, and is emitted in the side surface direction of the LED light emitting device 30. As a result, the blue light Pb and the yellow light Py are distributed over a wide range including the side surface direction from the upper surface of the LED light emitting device 40, and white light is emitted over a wide range by the combined light.

  As an example of the configuration of the LED light emitting device 30, an example in which ten fine openings 46 a are provided in the reflecting member 46 is shown. In practice, however, a larger number of fine openings 46 a are provided to adjust transmittance and reflectance. is there. As the reflecting member 46, a fine opening may be formed in the metal plate, or a fine mesh metal layer may be formed.

  In the first to third embodiments, examples of the blue LED and the YAG fluorescent resin have been described. However, the present invention is not limited to this, and it is natural that the present invention can be applied to various semiconductor light emitting elements and various fluorescent resins. In the first to third embodiments, plate-like members are used as the reflecting members 6 and 46. However, the reflecting member is not limited to a plate material, and for example, a resin kneaded with reflective particles is applied to a fluorescent resin and a transparent resin. Or a metal film formed by plating. The LED mounting method is not limited to FC mounting, but may be face-up mounting using wire bonding with the electrode surface facing upward.

(Reference example)
In the first to third embodiments, the LED 1 is flip-chip mounted on the rigid circuit board 2, and the fluorescent resin 7 whose adhesion is weakened is reinforced with the transparent resin 5. Next, a reference example without the circuit board 2 will be described with reference to FIG. 6 shows an LED light emitting device 40 in a reference example, (a) is a cross-sectional view of the LED light emitting device 40, (b) is a top view of the LED light emitting device 40 shown in (a), (c) is a side view, d) shows a bottom view.

  In the cross-sectional view of the LED light-emitting device 40 shown in FIG. 6A, a point that is greatly different from the LED light-emitting device 10 of the first embodiment shown in FIG. In the LED light emitting device 40, only the bottom surface is exposed while the two electrodes 23 are embedded in the reflective resin layer 22. Recently, the die size of the LED 21 has been increased, and the pitch of the electrodes 23 formed on the bottom surface of the LED 21 can be directly mounted on the mother board (mounting board). The electrode 23 is a protruding electrode of the LED 21, and the upper surface and the side surface of the LED 21 are covered with the fluorescent resin 7 with the electrode 23 facing down. The fluorescent resin 7 is bonded to the reflecting member 6 on the fluorescent resin upper surface 7a. Further, the transparent resin 5 is filled in the gap around the fluorescent resin 7 and formed by the reflective member 7 and the reflective resin layer 22. In this case, it is preferable that the reflecting member 6 has rigidity, and a fluorescent resin containing a phosphor and having reduced adhesive force and elasticity by bonding the reflecting member 6 and the reflective resin layer 22 to the transparent member 5. 7 is reinforced.

Next, the overall configuration of the LED light emitting device 40 will be described with reference to FIGS.
FIG. 6B is a top view of the LED light emitting device 40, FIG. 6A corresponds to the AA cross-sectional view of FIG. 6B, and FIGS. 6B and 6C are basically in the first embodiment. The same description as in FIGS. 1B and 1C is omitted.

  FIG. 6D is a bottom view of the LED light emitting device 40, and the exposed portion of the electrode 23 is in the region inside the reflective resin layer 22. The reflective resin layer 22 reflects light emitted from the LED 21 and light emitted from the fluorescent particles. Compared with the LED light-emitting devices 10, 20, and 30 in the first to third embodiments, the LED light-emitting device 40 can be thinned by a difference in thickness between the circuit board 2 and the reflective resin layer 22, and the circuit board. It is an advantage that there are few components because there is no 2.

1, 21, 101, 201 LED (semiconductor light emitting device)
2, 102, 202 Circuit board 2d Stepped portion 3a, 103a, 103b Wiring electrode 3b Through-hole electrode 3c, 103c Drive electrode 5 Transparent resin 6, 46, 106, 206 Reflective member 6a Groove 7 Fluorescent resin (fluorescent member)
7a Fluorescent resin upper surface 10, 20, 30, 40, 100, 200 LED light emitting device (semiconductor light emitting device)
22 Reflective resin layer 23 Electrode 46a Micro opening 105, 205 Translucent resin 105a Translucent resin upper surface Pb Blue light Py Yellow light

Claims (4)

In a semiconductor light emitting device comprising a semiconductor light emitting device having at least a side surface and an upper surface covered with a fluorescent member, a circuit board on which the semiconductor light emitting device is mounted, and a reflective member on the upper surface of the fluorescent member, A transparent member is provided in a region sandwiched between the circuit board and the reflective member , the reflective member is made of a harder material than the fluorescent member, the reflective member is attached to the fluorescent member, and the reflective member A semiconductor light emitting device comprising a groove on an upper surface of a member .   The semiconductor light emitting device according to claim 1, wherein a step portion is provided around the circuit board, and the step portion and the transparent member are engaged with each other. The semiconductor light-emitting device according to claim 1, wherein the reflective member is transmissive. The semiconductor light emitting device according to claim 3 , wherein the reflecting member has a transmissive minute opening.

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