JP2018078170A - Semiconductor light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve high luminous efficiency and suppression of color unevenness in a luminous surface.SOLUTION: The semiconductor light-emitting device includes: a light-emitting element 10; a wavelength conversion layer 12 for converting the light emitted from the light-emitting element into the light with a predetermined wavelength; a light reflection member 13 covering at least a side face of the wavelength conversion layer; and a thin film 14 provided on an outermost surface from which the light subjected to wavelength conversion in the wavelength conversion layer emits, which has a property of rejecting the uncured light reflection member and whose surface is coarse.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a semiconductor light emitting device that converts light from a light emitting element into light having a desired wavelength by a wavelength conversion member and irradiates the light.

  2. Description of the Related Art A semiconductor light emitting device that irradiates white light by converting the wavelength of light emitted from a semiconductor light emitting element by a wavelength conversion member is known. Such a semiconductor light-emitting device is used as a light source for lighting fixtures such as general lighting, street lamps, and vehicular lamps. In particular, since vehicular lamps and the like require high front luminance, various semiconductor light-emitting devices are used. Has been proposed.

  For example, Patent Document 1 discloses a light-emitting element, a light-transmitting member that has a light-emitting surface exposed to the outside and a side surface continuous from the light-emitting surface, and that can convert the wavelength of light from the light-emitting element, and a side surface of the light-transmitting member. And a covering member containing a light-reflective material that covers the side surface of the light-emitting element, and substantially only the light-emitting surface on the upper surface serves as a light emission region in the light-emitting device, thereby improving the front luminance. A light emitting device is disclosed.

Japanese Patent No. 552682

  By the way, since the light transmissive member applied to the semiconductor light emitting device disclosed in Patent Document 1 described above is composed of an inorganic material having a flat light emitting surface, light emitted from the light emitting element is reflected on the light emitting surface. It is reflected and cannot be emitted to the outside from the light emitting surface, and the light emission efficiency is lowered. On the other hand, in order to improve this, there is a semiconductor light emitting device in which the surface of the light emitting surface is roughened, that is, an uneven surface is formed on the surface of the light emitting surface. However, when the surface of the light emitting surface is roughened, a problem arises that the covering member crawls up to the light emitting surface when a covering member containing a light reflecting material during the manufacturing process of the semiconductor light emitting device is applied. In particular, when a resin is used as the covering member, a capillary phenomenon occurs on the rough surface of the light emitting surface, and the resin is easily spread. In addition, when the corner of the light emitting surface is rounded, the resin stops due to surface tension is weak, and the resin tends to spread and spread on the light emitting surface. As described above, the resin crawls up on the surface of the light emitting surface and spreads wet, so that the surface area of the light emitting surface is narrowed and the light emission efficiency may be reduced.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the creeping of the covering member on the light emitting surface and to improve the light emission efficiency.

  One embodiment of the present invention includes a light emitting element, a wavelength conversion layer that converts light emitted from the light emitting element into light having a predetermined wavelength, a light reflecting member that covers at least a side surface of the wavelength conversion layer, and the wavelength conversion layer. And a thin film having a property of repelling the uncured light reflecting member provided on the outermost surface from which the wavelength-converted light is emitted.

  In another aspect of the present invention, a light-emitting element, a wavelength conversion layer that converts light emitted from the light-emitting element into light having a predetermined wavelength, and light transmission that transmits light converted in wavelength by the wavelength conversion layer An uncured, provided on the outermost surface of the light transmitting substrate, the light reflecting member that covers at least the side surface of the light transmitting substrate, and the light that is wavelength-converted by the wavelength conversion layer of the light transmitting substrate. There is provided a semiconductor light emitting device including a thin film having a property of repelling a light reflecting member.

  In each of the above embodiments, the surface of the thin film is rough, the contact angle with respect to the uncured coating member on the thin film is larger than the contact angle on the wavelength conversion layer and the light-transmitting substrate, and the thin film is a fluororesin It is preferable that the thickness of the thin film is 1 nm to 10 μm, more preferably 50 nm to 1 μm. Moreover, it is preferable that the contact angle of a thin film is 40 degrees or more.

  ADVANTAGE OF THE INVENTION According to this invention, the climbing of the coating | coated member to the light emission surface surface can be suppressed, and luminous efficiency can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic structure of the semiconductor light-emitting device concerning the 1st Embodiment of this invention is shown, (A) is sectional drawing, (B) is a top view. 1 shows a schematic configuration of a semiconductor light emitting device according to another example of the first embodiment of the present invention, in which (A) is a cross-sectional view and (B) is a top view. 1 shows a schematic configuration of a semiconductor light emitting device according to another example of the first embodiment of the present invention, in which (A) is a cross-sectional view and (B) is a top view. It is sectional drawing which shows schematic structure of the semiconductor light-emitting device concerning the 2nd Embodiment of this invention. 1 is a top view showing a schematic configuration when a wire bonding type light emitting element is applied to a semiconductor light emitting device according to a first embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings shown below, hatching is appropriately omitted even in a cross-sectional view for easy understanding and improved visibility. Further, in the top view of the semiconductor light emitting device, components that are not originally visible in the top view are indicated by broken lines and hatched for convenience of explanation. Further, in the following description, even in the case of different embodiments and modifications, the same components are denoted by the same reference numerals, and the description thereof is omitted.

(First embodiment)
A semiconductor light emitting device according to a first embodiment of the present invention will be described.
The semiconductor light emitting device according to this embodiment includes a light emitting element 10, a wavelength conversion layer 12 that converts light emitted from the light emitting element into light of a predetermined wavelength, a light reflecting member that covers at least a side surface of the wavelength conversion layer, a wavelength The thin film is provided on the outermost surface from which the light whose wavelength has been converted by the conversion layer is emitted, and has a rough surface and a contact angle larger than that of the wavelength conversion layer.

  More specifically, FIG. 1A is a cross-sectional view of the semiconductor light emitting device 1, FIG. 1B is a top view of the semiconductor light emitting device 1, and the semiconductor light emitting device 1 emits light as shown in FIG. An element 10, a mounting substrate 11 on which the light emitting element 10 is mounted, a wavelength conversion layer 12, a light reflecting member 13, and a thin film 14 are provided.

  The light-emitting element 10 has a rectangular shape in a top view, and has a flip chip structure in which a semiconductor layer and a light-emitting layer are stacked on a substrate transparent to light to be emitted and a power supply electrode is inverted. ing. The light emitting element 10 irradiates light emitted from the light emitting layer to the outside. Therefore, the upper surface and the side surface of the light emitting element 10 are light emitting surfaces. The electrode of the light emitting element 10 is electrically connected to the wiring pattern on the mounting substrate 11 by a bump or the like (not shown).

In the present embodiment, the mounting substrate 11 is a plate-like body made of a ceramic material, and a plate-like substrate made of aluminum nitride is applied. In general, the substrate is formed of an insulating material such as glass epoxy, resin, or ceramic, or a composite material of an insulating material and a metal member. As the substrate, those using ceramics or resin having high heat resistance and high weather resistance are preferable.
Note that a wiring pattern (not shown) is formed on the mounting substrate 11. The wiring pattern is mainly formed on the surface of the mounting substrate 11 as a mounting pattern of the light emitting element 10 and a current routing pattern for supplying power to the light emitting element 10. As the wiring pattern, a conductive material such as Al, Ni, Cu, Ag, or Au can be used.

  The wavelength conversion layer 12 includes a phosphor that converts light emitted from the light emitting element 10 into light having a desired wavelength, and is provided on the upper surface of the light emitting element 10. More specifically, the wavelength conversion layer 12 includes, for example, a ceramic and phosphor mixture or sintered body, a glass and phosphor mixture, a ceramic having a phosphor film disposed thereon, a glass on which a phosphor film is formed, a phosphor A body-dispersed glass or a phosphor ceramic plate can be applied. In the present embodiment, the wavelength conversion layer 12 has substantially the same size as the light emitting surface on the upper surface of the light emitting element 10, and the upper surface is a rough surface. The thickness of the wavelength conversion layer is preferably, for example, about 10 μm to 500 μm, particularly about 30 μm to 250 μm.

  The light reflecting member 13 is provided so as to cover the side surface of the wavelength conversion layer 12 and to expose the upper surface of the wavelength conversion layer 12 to the outside. As the light reflecting member 13, for example, a silicone resin mixed with a light reflecting filler (for example, titanium oxide, aluminum oxide, zirconium oxide, zinc oxide, etc.) in a predetermined amount can be applied.

  The thin film 14 is provided on the outermost surface of the semiconductor light emitting device. In this embodiment, it is provided on the upper surface of the wavelength conversion layer 12, and is provided on the rough surface of the upper surface of the wavelength conversion layer 12 with a uniform film thickness. Therefore, the surface of the thin film 14 is a rough surface. Further, as the thin film 14, a material having a larger contact angle with respect to the uncured light reflecting member than the wavelength conversion layer 12 is selected and applied. More specifically, a material that repels the light reflecting member 13 in a liquid state before being cured is applied as the thin film 14. Moreover, it is preferable that the contact angle with respect to the water of the thin film 14 is 40 degrees or more. For example, the contact angle of water of 40 ° or more can be maintained by applying a material excellent in non-adhesiveness and slipperiness such as a fluororesin. In addition, as the thin film 14, an organic substance such as an organoepoxy can be applied.

  The thickness of the thin film is preferably 1 nm to 10 μm, more preferably 50 nm to 1 μm, and still more preferably 50 nm to 100 nm. In the present embodiment, since the upper surface of the wavelength conversion layer 12 is rough, by depositing the thin film 14 on the wavelength conversion layer 12 with a uniform film thickness, the unevenness of the wavelength conversion layer 12 is followed. The top surface is also a rough surface with irregularities maintained. The thin film 14 is preferably formed in advance on the upper surface of the wavelength conversion layer 12 by, for example, a spin coater or spray.

The semiconductor light emitting device configured as described above is manufactured as follows.
Prior to the manufacture of the semiconductor light emitting device, a thin film 14 made of a fluororesin is formed on the phosphor ceramic plate that becomes the wavelength conversion layer 12. The phosphor ceramic plate has a phosphor concentration and thickness adjusted in advance, and is cut into a desired size after the thin film 14 is formed. In the present embodiment, the phosphor ceramic plate serving as the wavelength conversion layer 12 is cut to approximately the same size as the upper surface of the light emitting element 10.

  Then, the light emitting element 10 is mounted on a mounting substrate 11 on which a wiring pattern (not shown) is formed in advance via bumps (not shown). Next, a phosphor ceramic plate on which the thin film 14 has been formed in advance and cut to approximately the same size as the upper surface of the light emitting element 10 is coated with a resin for adhering the phosphor ceramic plate, mounted on the upper surface of the light emitting element 10, and the resin is heated. Curing is performed to obtain the wavelength conversion layer 12 and the thin film 14.

  Next, a light reflecting member in which a predetermined amount of a light reflecting filler is mixed with uncured silicone resin in advance is poured onto the mounting substrate 11 until the side surfaces of the light emitting element 10 and the wavelength conversion layer 12 are completely surrounded. At this time, the poured light reflection member 13 has the highest boundary between the wavelength conversion layer 12 and the light reflection member 13 and gradually decreases as the distance from the wavelength conversion layer 12 increases. When the semiconductor light emitting device has a cavity, the height increases from the lowered portion toward the upper surface of the cavity, and when the upper surface of the cavity is higher than the wavelength conversion layer, the height of the covering member is highest at the cavity and the connection portion.

As described above, the light reflecting member 13 rises toward the wavelength conversion layer 12, and causes a capillary phenomenon on the rough surface of the wavelength conversion layer 12 so as to be wet and spread. However, since the thin film 14 that repels the uncured light reflecting member 13 is formed on the upper surface of the wavelength conversion layer 12, the light reflecting member 13 is prevented from creeping up and spreading over the wavelength conversion layer 12. In this state, the light reflecting member 13 is cured by an appropriate curing method such as heating or ultraviolet irradiation, and diced to a predetermined size so that the light reflecting member 13 covers the side surface of the wavelength conversion layer 12 as a piece. The manufactured semiconductor light emitting device can be manufactured.
In this way, the light reflecting member 13 is suppressed from creeping and spreading on the wavelength conversion layer 12, so that the rough surface shape of the upper surface of the wavelength conversion layer 12 is maintained, and the light emission efficiency resulting from the creeping of the light reflecting member is maintained. Reduction in brightness and brightness can be suppressed.

In the present embodiment, the example in which the wavelength conversion layer 12 is approximately the same size as the upper surface of the light emitting element 10 has been described. For example, as illustrated in FIGS. 2A and 2B, the wavelength conversion layer 12 emits light. The size may be smaller than the upper surface of the element 10. 3A and 3B, the wavelength conversion layer 12 may be larger than the upper surface of the light emitting element 10.
Furthermore, when the surface of the wavelength conversion layer 12 is not a rough surface but a flat surface, the surface of the thin film 14 is made rough so that the light reflecting member 13 rises and spreads on the wavelength conversion layer 12 in the same manner. Is suppressed, and a decrease in luminous efficiency and a decrease in brightness can be suppressed.

  In addition, when forming the thin film 14 on the upper surface of the wavelength conversion layer 12, it is possible that the thin film 14 is thick on the concave portion on the rough surface and thin on the convex portion, and the uneven shape is slightly smooth. In this case, the rough surface is not completely flat, and the uneven shape of the rough surface can be maintained, so that the light emission efficiency can be maintained.

(Second Embodiment)
Next, a semiconductor light emitting device according to a second embodiment of the present invention will be described.
In the above-described first embodiment of the present invention, the example in which the thin film is formed on the upper surface of the wavelength conversion layer 12 has been described. In the present embodiment, an example in which a semiconductor light emitting device includes a light transmissive substrate and the thin film 14 is formed on the light transmissive substrate will be described. FIG. 4 is a cross-sectional view of the semiconductor light emitting device according to this embodiment. In the following description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  The semiconductor light emitting device according to this embodiment transmits a light emitting element 10, a wavelength conversion layer 12 that converts light emitted from the light emitting element 10 into light having a predetermined wavelength, and light that has been wavelength converted by the wavelength conversion layer 12. The light-transmitting substrate 15, the light reflecting member 13 that covers at least the side surface of the light-transmitting substrate 15, and the outermost surface from which the light whose wavelength has been converted by the wavelength conversion layer 12 is emitted. And a thin film having a larger contact angle than the conductive substrate 15.

The light transmissive substrate 15 is made of, for example, glass, sapphire, silicone resin, or the like, and has substantially the same area as the wavelength conversion layer 12 in the present embodiment, and is disposed on the upper surface of the wavelength conversion layer 12.
The thin film 14 is provided on the outermost surface of the semiconductor light emitting device, as in the first embodiment described above. Therefore, in the present embodiment, the light-transmitting substrate 15 is provided on the upper surface, and the light-transmitting substrate 15 is provided on the rough surface of the light-transmitting substrate 15 with a uniform film thickness. Therefore, the surface of the thin film 14 is a rough surface. Further, as the thin film 14, a material having a larger contact angle with respect to the uncured light reflecting member than the light transmissive substrate 15 is selected and applied. More specifically, as the thin film 14, a material that repels the light reflecting member 13 in a liquid state before being cured and has a contact angle with water of 40 ° or more is applied. For example, the contact angle of water of 40 ° or more can be maintained by applying a material excellent in non-adhesiveness and slipperiness such as a fluororesin.

  The thickness of the thin film is preferably 1 nm to 10 μm, and more preferably 50 nm to 1 μm. In the present embodiment, since the upper surface of the light transmissive substrate 15 is rough, the thin film 14 is spread on the wavelength conversion layer 12 with a uniform film thickness to follow the unevenness of the light transmissive substrate 15, and the thin film The upper surface of 14 is also a rough surface with unevenness maintained. The thin film 14 is preferably formed in advance on the upper surface of the light transmissive substrate 15 by, for example, a spin coater or spray.

The semiconductor light emitting device configured as described above is manufactured as follows.
Prior to the manufacture of the semiconductor light emitting device, a thin film 14 made of a fluororesin is formed on a plate-like member such as glass that becomes the light transmissive substrate 15. The light transmissive substrate 15 is cut into a desired size after the thin film 14 is formed. In the present embodiment, the light transmissive substrate 15 is cut to approximately the same size as the upper surfaces of the light emitting element 10 and the wavelength conversion layer 12.
Then, the light emitting element 10 is mounted on a mounting substrate 11 on which a wiring pattern (not shown) is formed in advance via bumps (not shown). Next, the phosphor ceramic plate is coated with a phosphor ceramic plate bonding resin and mounted on the upper surface of the light emitting element 10, and the phosphor ceramic plate bonding resin is coated to form the wavelength conversion layer 12. Subsequently, a light transmitting substrate 15 having a thin film 14 formed on the upper surface of the wavelength conversion layer 12 is mounted and fixed.

  Next, a light reflecting member in which a predetermined amount of a light reflecting filler is mixed with silicone resin is poured onto the mounting substrate 11 until the side surfaces of the light emitting element 10 and the light transmitting substrate 15 are completely surrounded. At this time, the poured light reflecting member 13 has the highest boundary between the light transmitting substrate 15 and the light reflecting member 13 and gradually decreases as the distance from the light transmitting substrate 15 increases.

The light reflecting member 13 crawls up toward the light transmissive substrate 15, and causes a capillary phenomenon on the rough surface of the light transmissive substrate 15 to try to spread. However, since the thin film 14 that repels the light reflecting member is formed on the upper surface of the light transmissive substrate 15, the light reflecting member 13 is suppressed from creeping up and spreading to the wavelength conversion layer 12. In this state, by heating and curing and dicing cutting to a predetermined size, it is possible to manufacture a semiconductor light emitting device in which the light reflecting member 13 is separated as a structure covering the side surface of the light transmissive substrate 15.
As described above, since the light reflecting member 13 is suppressed from creeping and spreading on the light-transmitting substrate 15, it is possible to suppress a decrease in light emission efficiency and a decrease in brightness due to the light reflecting member scooping up. .

  Note that FIG. 5 shows an example in which a wire bonding type light emitting element that supplies power via a bonding wire connected to the upper surface of the light emitting element is applied. In FIG. 5, the wavelength conversion layer 12 is disposed on the upper surface of the light emitting element 10, that is, on the light emitting surface side. In this example, in order to dispose the wire on the upper surface of the light emitting element 10, a notch 12 </ b> A for allowing the wire to escape is formed in the wavelength conversion layer 12. In the figure, a notch is provided at the center of any one side of the wavelength conversion layer 12, but the position of the notch can be determined as appropriate, such as the element center, corner, and side, and the number of wires is one, Multiple lines can be determined as appropriate.

The semiconductor light emitting device according to each embodiment described above can be applied to a light source of a headlamp or an ADB (Adaptive Driving Beam) type vehicle lamp, and can also be applied to a general lamp for illumination or the like. .
The height of the light reflecting member 13 tends to decrease as the distance from the wavelength conversion layer 12 or the light transmissive substrate 15 increases. When this becomes significant, light from the side surface of the wavelength conversion layer 12 or the light transmissive substrate 15 is observed. When the semiconductor light-emitting device is applied to, for example, a vehicular lamp, the problem of glare occurs. By providing the thin film 14 in each of the above-described embodiments, the height of the light reflecting member 13 can be increased, so that the shape of the light reflecting member 13 is substantially flat with respect to the wavelength conversion layer 12 or the light transmissive substrate 15. It can be made into the shape which spreads. Thereby, the problem of glare when used for a vehicle headlamp can be avoided.

DESCRIPTION OF SYMBOLS 10 ... Light emitting element, 11 ... Mounting board, 12 ... Wavelength conversion layer, 13 ... Light reflection member, 14 ... Thin film, 15 ... Light transmissive board | substrate

Claims (10)

A light emitting element;
A wavelength conversion layer that converts light emitted from the light emitting element into light of a predetermined wavelength;
A light reflecting member covering at least a side surface of the wavelength conversion layer;
A semiconductor light emitting device comprising: a thin film provided on the outermost surface from which the wavelength-converted light of the wavelength conversion layer is emitted, repels the uncured light reflecting member, and has a rough surface. A light emitting element;
A wavelength conversion layer that converts light emitted from the light emitting element into light of a predetermined wavelength;
A light transmissive substrate that transmits the light wavelength-converted by the wavelength conversion layer;
A light reflecting member covering at least a side surface of the light transmissive substrate;
A thin film having a property of repelling the uncured light reflecting member and having a rough surface provided on the outermost surface of the light transmissive substrate from which the light wavelength-converted by the wavelength conversion layer is emitted. A semiconductor light emitting device provided.   The semiconductor light emitting device according to claim 1, wherein the thin film has a larger contact angle with respect to the uncured light reflecting member than the wavelength conversion layer.   The semiconductor light emitting device according to claim 2, wherein the thin film has a larger contact angle with respect to the uncured light reflecting member than the light transmissive substrate.   The semiconductor light emitting device according to claim 1, wherein an upper surface of the wavelength conversion layer is a rough surface.   The semiconductor light emitting device according to claim 2, wherein an upper surface of the light transmissive substrate is a rough surface.   The semiconductor light-emitting device according to claim 1, wherein the thin film is made of an organic material.   The semiconductor light-emitting device according to claim 1, wherein the thin film is made of a fluororesin. The semiconductor light emitting device according to claim 1, wherein the thin film has a thickness of 1 nm to 10 μm.
Body light emitting device.   The semiconductor light emitting device according to any one of claims 1 to 9, wherein the thin film has a contact angle with water of 40 ° or more.

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