Light emitting device having light shielding member formed in recess of cover member and method for manufacturing the same

A light emitting device manufacturing method includes: disposing n pieces of light emitting elements in m rows on a substrate block, where an interval between a kth light emitting element from one end of rows and a (k+1)th light emitting element has a first distance; disposing a phosphor member on the light emitting elements; disposing a frame member to surround the light emitting elements; disposing a cover member in each area surrounded by the frame member to cover lateral surfaces of the light emitting elements and the phosphor members while forming recesses at an upper surface between the kth light emitting elements and the (k+1)th light emitting elements apart by the first distance; disposing a light shielding member in each recess; and cutting the light shielding members, the cover members, and the substrate block between the light emitting elements that are apart by the first distance.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2018-247903, filed on Dec. 28, 2018, the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to a light emitting device and a method for manufacturing the same.

LEDs are utilized in a broad range of applications. One of the applications is a light source for an automotive headlight. Considering the protection of oncoming drivers and pedestrians from glare, automotive headlights need to have a sharp cutoff line. For this reason, light sources designed for headlights need to achieve a sharp cutoff line when applied to headlights. For such a light source, Japanese Patent Publication 2012-59939, for example, proposes a high cutoff performance light emitting device achieved by disposing a light shielding member in the periphery of the light emission surface. The high cutoff performance in the patent publication refers to a large difference in luminance between the upper surface of the transparent member (i.e., light emission surface) and the periphery thereof, and the light emitting device disclosed in the patent publication is described as being able to provide a high performance headlight by way of appropriately designing the layout of light emitting elements and the shape of the transparent member.

SUMMARY

In the light emitting device proposed in the aforementioned patent publication, however, the light shielding member is disposed between the lateral surfaces of the transparent member and the outer frame. This makes it difficult to reduce the size of the device.

Accordingly, one object of the present disclosure is to provide a small sized light emitting device and a method of manufacturing a light emitting device.

A method of manufacturing a light emitting device according to certain embodiment of the present disclosure includes: disposing a plurality (n×m pieces) of light emitting elements on an upper surface of a substrate block arranged in m rows (m is an integer equal to or larger than 1), each row including n pieces (n is an even number equal to or larger than 2), where an interval between a kth (k is an odd number smaller than n) light emitting element from one end of rows and a (k+1)th light emitting element has a first distance; disposing a phosphor member on each light emission surface of the plurality (n×m pieces) of light emitting elements; disposing a frame member on the upper surface of the substrate block so as to surround the plurality (n×m pieces) of light emitting elements; disposing a cover member in each area surrounded by the frame member so as to cover lateral surfaces of the plurality (n×m pieces) of light emitting elements and lateral surfaces of the phosphor members while forming recesses at an upper surface between the kth light emitting elements and the (k+1)th light emitting elements which are separated by the first distance; disposing a light shielding member in each of the recesses; and dividing into individual light emitting devices by cutting the light shielding members, the cover members, and the substrate block between the light emitting elements that are separated by the first distance.

A light emitting device according to certain embodiment of the present disclosure includes: a substrate; a light emitting element disposed on an upper surface of the substrate; a phosphor member having a quadrilateral upper surface and a lower surface opposing the quadrilateral upper surface, and disposed such that the lower surface faces a light emission surface of the light emitting element; a cover member disposed to cover lateral surfaces of the light emitting element and lateral surfaces of the phosphor member while exposing an upper surface of the phosphor member; and a light shielding member disposed on an upper surface of the cover member along a portion of a perimeter of the upper surface of the phosphor member. A portion of the cover member on which the light shielding member is disposed has a height from an upper surface thereof to the upper surface of the substrate so as to be lower closer to an outer edge side than on a phosphor member side.

The embodiments of the present disclosure described above can provide a small sized light emitting device and a method of manufacturing a light emitting device.

DESCRIPTION

Certain embodiments and examples of the present disclosure will be explained below with reference to the drawings. The light emitting devices explained below are for giving shape to the technical ideas of the present invention, and are not intended to limit the present invention unless otherwise specifically noted.

In each drawing, the same reference numerals denote the members having the same functions. To make the features easily understood, the descriptions of the features are distributed among the embodiments and examples, but the constituent elements described in different embodiments and examples can be replaced or combined in part. The explanation of common features already described in embodiments or examples appearing earlier might be omitted in the subsequent embodiments or examples where the explanation is focused only on the differences. Similar effects attributable to similar features, in particular, will not be mentioned each time an embodiment or example is discussed. The sizes of and positional relationships between the members shown in each drawing might be exaggerated for clarity of explanation.

For example, when employed as the light source of a headlight, the light emitting device according to an embodiment of the present disclosure needs to be small sized and capable of achieving a sharp cutoff line. It is proposed that manufacturing a light emitting device having a quadrilateral light emission surface such that the luminance sharply changes between the inside and the outside of the boundary between the light emission surface and the cover member surrounding the perimeter of the light emission surface at least along one side of the light emission surface. Such light emitting device can have a sharp cutoff line with a simple configuration of an optical system when employed as the light source of a headlight. For example, when at least one side of a quadrilateral light emission surface becomes the boundary where the luminance sharply changes, by appropriately designing an optical system to control the emitted light from the light emitting element, a sharp cutoff line can be achieved when used as the light source of a headlight even if the luminance change is not sharp at the boundary along the other sides.

Light emitting devices of certain embodiments will be specifically explained below.

FIG. 1is a schematic top view of a light emitting device100according to Embodiment 1, andFIG. 2is a schematic cross-sectional view taken along line A-A inFIG. 1.

The light emitting device100according to Embodiment 1 includes a substrate20, four light emitting elements10disposed on the upper surface20aof the substrate20, a phosphor member30, a cover member50, and a light shielding member60. The phosphor member30has a substantially quadrilateral upper surface and a lower surface which opposes the upper surface, and is disposed such that the lower surface faces the light emission surfaces10aof the four light emitting elements10. The light shielding member60is disposed on the upper surface of the cover member50along a portion of the perimeter of the upper surface of the phosphor member30. The portion of the upper surface of the cover member50on which the light shielding member60is disposed has a height from the upper surface thereof to the upper surface of the substrate20so as to be lower on the outer edge side than on the phosphor member side.

In the present embodiment, the cover member50is made of a material having reflectivity, and the light shielding member60is made of a material having higher reflectivity than that of the cover member50.

In the light emitting device100of Embodiment 1 described above, the lateral surfaces of the four light emitting elements10and the lateral surfaces of the phosphor member30are covered with the cover member50which has high reflectivity. Thus, the light subjected to wavelength conversion by the phosphor member30, or such converted wavelength light in combination with a portion of the light emitted by the light emitting elements10, is output from the upper surface (i.e., light exiting surface) of the phosphor member30which is the light emission surface of the light emitting device100.

Furthermore, in the light emitting device100of Embodiment 1, a light shielding member60is further disposed on the cover member50along a portion of the perimeter of the upper surface of the phosphor member30. Thus, the light leaking from the upper surface of the cover member50can be blocked by the light shielding member60to thereby increase the luminance difference between the light emission surface and non-light emission surface of the light emitting device100on the light exiting surface side.

In the case of employing the light emitting device100of Embodiment 1, which can sharply reduce the luminance in a region adjacent to the perimeter of the light exiting surface, for example, as the light source of a headlight, a sharp cutoff line can be achieved by suitably designing an optical system that can optically control the light exiting from the light emitting device with a relatively simple structure.

A specific example of the light emitting device of Embodiment 1 and its constituent elements will be explained in more detail below with reference to the drawings.

The substrate20is a member on which light emitting elements10are mounted, and externally electrically connects the light emitting device. The substrate20has a quadrilateral upper surface20aand a lower surface20beach having long and short sides. Furthermore, a first electrode21and a second electrode22are formed on the upper surface20aof the substrate20. Four light emitting elements10each have a quadrilateral upper surface and a lower surface opposing the upper surface, where the upper surface serves as a primary light emission surface10aand the lower surface has a first electrode11and the second electrode12. The four light emitting elements10are lined up on the upper surface20aof the substrate20along the long sides of the upper surface20a. In the present embodiment, in the light emitting device of Embodiment 1, the light emitting elements10are disposed such that one side of each upper surface (i.e., each light emission surface10a) is positioned on a straight line (i.e., first straight line) paralleling the long sides of the upper surface20aof the substrate20, and each opposing side is positioned on a second straight line paralleling the first straight line. The light emitting elements10are serially or parallelly connected between the first electrode21and the second electrode22of the substrate20via the first electrodes11and the second electrodes12. In the light emitting device100of Embodiment 1, a protective element90is disposed on the upper surface20aof the substrate20. The protective element90is disposed in the area directly under the light shielding member60.

The main material for the substrate20preferably employs an insulating material that does not readily transmit the light from the light emitting elements or the external light. Specific examples include ceramics such as alumina, aluminum nitride, or the like, and resins such as phenol resins, epoxy resins, polyimide resins, BT resin, polyphthalamide, and the like. In the case of using a resin, an inorganic filler, such as glass fibers, silicon oxide, titanium oxide, alumina, or the like, may be mixed into the resin as needed. This can enhance the mechanical strength, reduce the thermal expansion coefficient, and increase the optical reflectance. Alternatively, the substrate20may be a metal material on which an insulating material is formed on. The first electrode21and the second electrode22in a predetermined pattern are formed on the insulating material. For the electrode material, at least one selected among gold, silver, copper and aluminum can be used. The wiring can be formed by plating, vapor deposition, sputtering, or the like.

Light emitting diodes are preferably used for the light emitting elements10. One having any wavelength can be selected. For example, for a blue or green light emitting element, one employing a nitride-based semiconductor (InXAlYGa1-X-YN, 0≤X, 0≤Y, X+Y≤1), ZnSe, or GaP can be used. For a red light emitting element, GaAlAs, AlInGaP, or the like can be used. Semiconductor light emitting elements made of materials other than these can alternatively be used. The composition, emission color, size, or number of the light emitting elements employed can be suitably selected in accordance with the purpose. Suitable examples of the materials used in a light emitting device having a phosphor include nitride semiconductors (InXAlYGa1-X-YN, 0≤X, 0≤Y, X+Y≤1) which can efficiently excite the phosphor and emit light having a short wavelength. Various emission wavelengths can be selected depending on the semiconductor materials and the mixed crystal composition ratio.

The light emitting elements10have positive and negative electrodes, for example, on the same surface, and are flip-chip mounted on the substrate20with the positive and negative electrode side facing down as shown inFIG. 2. Each light emitting element10uses the upper surface, which opposes the lower surface having the electrodes, as the principal light exiting surface. Such a light emitting element10, as described above, is connected on the substrate using a conductive bonding material, such as bumps, conductive paste, or the like. This can provide large contact areas between the electrodes and the substrate to thereby reduce the interconnection resistance, as compared to a light emitting element connected using metal wires.

The light emitting element10is, for example, one formed on a light transmissive support substrate on which nitride semiconductor layers are formed, and the support substrate side becomes the upper surface, which is the principal light exiting surface, of the light emitting element10. The support substrate can be removed. The removal of the support substrate can be performed, for example, by polishing, LLO (laser lift off), or the like.

The phosphor member30is a plate-like member having an upper surface30aand a lower surface30beach having long and short sides. The phosphor member30is disposed such that the lower surface30bfaces and collectively covers the light emission surfaces10aof the four light emitting elements10. The upper surface30aand the lower surface30bof the phosphor member30, for example, have the same shape. The lengths of the long sides of the phosphor member30are, for example, set to be larger than the distance between the outer sides of the light emission surfaces10aof the two outermost light emitting elements10among the array of four light emitting elements10. The lengths of the short sides of the phosphor member30are set to be larger than one side of the light emission surface10aof a light emitting element10. In the light emitting device100of Embodiment 1, the phosphor member30described above is disposed such that (i) one of the long sides is positioned outward of the first straight line, and the other one of the long sides which opposes to the side closer to the first straight line is outward of the second straight line in each light emission surface10a, and (ii) the short sides are positioned outward of the outer sides of the two outermost light emitting elements10.

Examples of materials used for the phosphor member30include a sintered body of phosphor, or phosphor powder-containing body formed using a resin, glass, ceramic or other inorganic materials. Alternatively, the phosphor member may be a formed using resin, glass, ceramic, or the like having a phosphor-containing layer formed on the surface. The phosphor member may contain a filler such as a light diffuser depending on the purpose. The phosphor member has a flat plate shape, for example, and the thickness thereof can be in a range of about 50 μm to about 300 μm.

The phosphor contained in the phosphor member is excitable by the emitted light from the light emitting elements10. Examples of phosphors excitable by a blue or ultraviolet light emitting element include cerium-activated yttrium aluminum garnet-based phosphors (YAG:Ce); cerium-activated lutetium aluminum garnet-based phosphors (LAG:Ce); europium and/or chromium-activated nitrogen-containing calcium aluminosilicate-based phosphors (CaO—Al2O3—SiO2); europium-activated silicate-based phosphors ((Sr,Ba)2SiO4); nitride-based phosphors such as β-SiAlON, CASN-based phosphors, SCASN-based phosphors; KSF-based phosphors (K2SiF6:Mn); sulfide-based phosphors, quantum dot phosphors, and the like. By combining these phosphors with a blue or ultraviolet light emitting element, a light emitting device of various emission colors (e.g., a white light emitting device) can be manufactured.

Frame Member

In the light emitting device100of Embodiment 1, a frame member4is disposed on the upper surface20aof the substrate20. The frame member4partitions the upper surface into a first region and a second region. The first region is a region where the four light emitting elements10, the phosphor member30, and the protective element90are disposed. The second region is a region where a portion of the first electrode21and a portion of the second electrode22are exposed. The frame member4is made of a material having high reflectivity, for example, a resin in which a light diffuser is dispersed. The portion of the first electrode21and the portion of the second electrode22exposed in the second region serve as external connection terminals of the light emitting device100.

The frame member4can be formed by using, for example, a resin material. Examples of usable resin material include a silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, acrylic resin, or the like. The resin material used to form the frame member may be a light transmissive resin, a white resin containing a light reflecting substance, or a black resin containing a light-absorbing substance.

The frame member4can be formed using ceramic or resin and bonded to the substrate20. Alternatively, the frame member4may be integrally formed with the substrate20.

The frame member4is preferably disposed such that the upper edge of the frame member4is higher than the light emitting elements10, but lower than the upper surface of the phosphor member30. This can inhibit the cover member50from running onto the upper surface of the phosphor member30when disposing the cover member50in the first region. Accordingly, interruption of light output that would be caused by running of the cover member50on the phosphor member30can be inhibit.

The cover member50is disposed in the first region of the upper surface20aof the substrate20to cover the lateral surfaces of the four light emitting elements10and the lateral surfaces of the phosphor member30while exposing the upper surface of the phosphor member30. In other words, the four light emitting elements10, the phosphor member30and the protective element90if included disposed in the first region of the upper surface20aof the substrate20are embedded in the cover member50while the upper surface of the phosphor member30is exposed. Because the light emitting device100of Embodiment 1 is manufactured by the method described later, for example, the first lateral surface50c1, the third lateral surface50c3, and the fourth lateral surface50c4of the cover member50(i.e., lateral surfaces except for the second lateral surface50c2that is in contact with the frame member40) are positioned coplanar with the lateral faces of the substrate20respectively positioned directly thereunder. Specifically, the first lateral surface50c1is positioned coplanar with the first lateral surface20c1of the substrate20, the third lateral surface50c3is positioned coplanar with the third lateral surface20c3of the substrate20, and the fourth lateral surface50c4is positioned coplanar with the fourth lateral surface20c4of the substrate20. Being manufactured by the method described later, the upper surface50aof the cover member50includes a first upper surface50a1, a second upper surface50a2, and third upper surfaces all having different planar directions. In the upper surface50aof the cover member50, the first upper surface50a1is the region between the long side on the first lateral surface50c1side and the side of the phosphor member30closer to the first lateral surface50c1side, the second upper surface50a2is the region between the long side on the second lateral surface50c2side and the side of the phosphor member30on the second lateral surface50c2side, and the third upper surfaces50a3are the upper surface50aexcluding the first upper surface50a1and the second upper surface50a2. In the light emitting device100of Embodiment 1 manufactured by the method described later, the height of the first upper surface50a1from the upper surface20aof the substrate20is lower on the outer edge side (i.e., on the first lateral surface50c1side) than on the phosphor member30side.

The cover member50can be formed, for example, of a resin material containing a light reflecting substance. The cover member50preferably has a reflectance of at least 60%, more preferably at least 80%, particularly preferably at least 90%, for the wavelength of the light emitted by the light emitting elements10.

For the base resin for the cover member, a silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, acrylic resin, or hybrid resin containing at least one of these resins can be used. The cover member can be formed by allowing a base material made of these resins to contain a light reflecting substance. For the light reflecting substance, an oxide containing any of Ti, Zr, Nb, Al, and Si, or AlN, MgF, or the like can be used. Preferably, titanium dioxide (TiO2) is used. Preferably, light reflecting particles having a different refractive index from that of the base resin is dispersed in the base resin. The light reflection amount and light transmittance amount differ depending on the concentration and density of the light reflecting substance contained in the resin. The concentration and density of the light reflecting substance can be suitably adjusted in accordance with the shape and size of the light emitting device.

The light shielding member60is partially disposed on the first upper surface50a1of the cover member50. In the upper surface50aof the cover member50, the light shielding member60is partially disposed along the side of the phosphor member30on the side closer to the first lateral surface50c1. The light shielding member60can be formed, for example, with a resin material containing a light shielding filler. For the base resin material, a silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, acrylic resin, or the like can be used. Examples of light shielding fillers include light-absorbing substances, such as pigments, carbon black, and the light reflecting substances described earlier. Among such examples, a black resin containing a light-absorbing substance such as carbon black is preferably used for the light shielding member60. The light shielding member60having a black colored body can absorb stray light such as return light, to thereby reduce such light to be externally released again. This can also increase the contrast with external light.

The thickness of the light shielding member60covering the upper surface of the cover member50is set so as to become thicker as the distance from the phosphor member30increases. In other words, a portion of the cover member on which the light shielding member is disposed has a height from the upper surface thereof to the upper surface of the substrate decreases as the distance from the phosphor member increases. This can increase the thickness of the light shielding member while securing the distance between the light shielding member and the lateral surface of the phosphor member, thereby reducing the light loss attributable to disposing of the light shielding member while blocking the light leaking from the upper surface of the cover member50. This can result in increasing the luminance difference between the light emission surface and the non-light emission surface of the light emitting device100on the light exiting side.

In the light emitting device100of Embodiment 1 described above, the lateral surfaces of the four light emitting elements10and the lateral surfaces of the phosphor member30are covered with the cover member50having a high reflectivity. This can reduce the output of light from the upper surface of the cover member50, thereby allowing the device to primarily output light from the upper surface (i.e., light exiting surface) of the phosphor member30. Even when a high reflective cover member50is used, however, the light exiting from the lateral surfaces of the light emitting elements10and the lateral surfaces of the phosphor member30can leak from the upper surface50aof the cover member50, particularly from the vicinity of the boundary with the phosphor member30. This can make the light exiting surface to be appeared larger than it is, making the light exiting surface appear spreading beyond the boundary between the upper surface of the phosphor member30and the upper surface50aof the cover member50, in other words, the boundary cannot be a so-called sharp-edged boundary. If such a light emitting device having no sharp-edged boundary is employed for a headlight requiring a sharp cutoff line, an optical system that can achieve a sharp cutoff line by controlling the irradiation direction of the light exiting from the light emitting device is needed, resulting in a complex optical system.

Accordingly, in the case of the light emitting device100of Embodiment 1, a light shielding member is disposed on the upper surface50aof the cover member50along the side of the phosphor member30closer to the first lateral surface50c1side. This can make the boundary of the phosphor member30appear sharp-edged in the vicinity along that side of the phosphor member30, and when used as the light emitting device for a headlight, a sharp cutoff line can be achieved with a relatively simple optical system.

In the upper surface50aof the cover member50, moreover, it is preferable to reduce the distances from the phosphor member30to the third lateral surface50c3and the fourth lateral surface50c4, to thereby make the boundary of the phosphor member30appear sharp-edged in the vicinities of the third lateral surface50c3and the fourth lateral surface50c4. The thickness of the cover member covering the lateral surfaces of the phosphor member30in this case, in other words, the distance between the phosphor member30and the third lateral surface50c3or the fourth lateral surface50c4in a top view, is preferably set to about 100 μm to about 400 μm. Although the reduced thickness of the cover member covering these lateral surfaces of the phosphor member may cause light leakage from the lateral surfaces, the third lateral surface and the fourth lateral surface can become the boundaries where the luminance sharply changes on the light emission surface side.

Next, a method of manufacturing a light emitting device according to Embodiment 1 will be explained with reference toFIG. 3, andFIGS. 4A to 4G.

FIGS. 4A to 4Gare schematic cross-sectional views each showing a process in the method of manufacturing a light emitting device according to Embodiment 1, andFIG. 3is a top view of what is shown inFIG. 4F.

The method of manufacturing a light emitting device of Embodiment 1 includes a light emitting element disposing process (FIG. 4B), a protective element disposing process (FIG. 4C), a phosphor member disposing process (FIG. 4D), a frame member disposing process (FIG. 4E), a cover member disposing process (FIG. 4F), a light shielding member disposing process (FIG. 4G), and a dividing process.

InFIG. 3andFIGS. 4A to 4G, the same reference numerals denote the same members before and after the light emitting devices are divided into individual pieces.

Light Emitting Element Disposing Process

In the light emitting element disposing process, a substrate block20on which a number of individual light emitting device regions are arranged is provided (FIG. 4A). On the upper surface of the substrate block20, a plurality of (n×m) pieces of light emitting elements are arranged in “m” rows (m is 1 an integer equal to or larger than 1) each including “n” pieces (n is an even number equal to or larger than 2). In the present embodiment, in each row, the n pieces of light emitting elements are disposed such that the interval between a “k”th light emitting element from one end (k is an odd number smaller than n) and the (k+1)th light emitting element is a first distance D1. In the example of Embodiment 1 shown inFIG. 3, the interval between the light emitting elements10arranged in the first column, i.e., the column at one end, and the light emitting elements10arranged in the second column, and the interval between the light emitting elements10arranged in the third column the light emitting elements10arranged in the fourth column from that end and, each have the first distance D1. Four columns each having16light emitting elements10are shown inFIG. 3. In the example shown inFIG. 3, n is 2 and m is 16. In other words, in this disclosure, n and m are defined by the number and the layout of the light emitting elements10surrounded by a frame member4, and inFIG. 3, two groups of (n×m) pieces of light emitting elements are shown.

In the manufacturing method according to Embodiment 1, each light emitting device includes four light emitting elements10. Thus, in each column, the four light emitting elements10included in a light emitting device are closely arranged at equal intervals, and a larger interval is provided between the light emitting elements10located at the opposing ends of two adjacent light emitting devices. The distance between the light emitting elements10in each light emitting device is, for example, about 100 μm to about 200 μm.

Protective Element Disposing Process

In the manufacturing method according to Embodiment 1, protective elements90are disposed on the substrate block for the light emitting elements10(FIG. 4C). The protective elements90are disposed, for example, between the lateral surface of a kth light emitting element and the lateral surface of the (k+1)th light emitting element10facing the kth light emitting element, in each row. In other words, the protective elements90are disposed between a kth light emitting element and the (k+1)th light emitting element so that the protective element90for the kth light emitting element and the protective element90corresponding to the (k+1)th light emitting element are next to each other. For example, in the dividing process, they are divided between the two protective elements90next to each other.

Phosphor Member Disposing Process

In the phosphor member disposing process, phosphor members30are disposed on each light emission surface of the plurality of (n×m) pieces of light emitting elements (FIG. 4D). The phosphor members30are bonded by using, for example, a light transmissive bonding member such as a silicone resin. In the case of composing the phosphor member30with a crystalline material, they can be bonded by, for example, thermocompression bonding.

Frame Member Disposing Process

In the frame member disposing process, frame members4each collectively surrounding (n×m) pieces of light emitting elements10are disposed on the upper surface of the substrate block20. For example, in the example shown inFIG. 3, two frame members4each collectively surrounds 16 pieces by 2 columns of light emitting elements10(FIG. 4E). In the manufacturing method according to Embodiment 1, the frame members4are specifically disposed such that each frame member4forms the boundary between the first region that includes the light emission region and the second region that includes the external connection region in each of the regions that will become light emitting devices following the dividing process. Specifically, a frame member4is disposed such that the first region where the four light emitting elements10, the phosphor member30, and the protective element90of each device will be located inward of the frame member4, and the second region which includes a portion of the first electrode21and a portion of the second electrode22will be located outward of the frame member4. In other words, the frame members4are formed to each collectively surround the first regions of the light emitting device regions disposed in a kth column and the first regions of the light emitting device regions disposed in the (k+1)th column. Forming frame members4in this manner can simplify the cover member disposing process described later which disposes cover members only in the first regions surrounded by the frame members4of the regions that will become light emitting devices after being divided into individual pieces.

For example, the frame members4are preferably formed to be lower than the upper surfaces of the phosphor members30as shown inFIG. 4E. The frame members4can be formed with a resin material or the like. For the resin material, for example, a thermosetting resin, such as a silicone resin, epoxy resin, or the like, is used. The resin is applied on the substrate20by using a dispenser or the like, and hardened. The resin material for the frame members4preferably contains a light reflecting material. This allows a frame member4to reflect the light exiting from the lateral surfaces of the light emitting elements10and the lateral surfaces of the phosphor member30of a device to exit from the upper surface of the phosphor member30(light emission surface) even when the cover member50is formed in a reduced space by shortening the distances from the frame member4to the light emitting elements and the phosphor members30. This can increase the light extraction efficiency and further reduce the size of the light emitting device.

Cover Member Disposing Process

In the cover member disposing process, a cover member is disposed in the region surrounded by each frame member4so as to cover the lateral surfaces of the (n×m) pieces of light emitting elements and the lateral surfaces of the phosphor members while exposing the upper surfaces of the phosphor members. The cover member forms curved recesses at the upper surface between kth light emitting elements and the (k+1)th light emitting elements which are apart by the first distance (FIG. 4F). In the cover member disposing process, for example, a resin material employed to form the cover members is disposed on the substrate upper surface between the frame members4and the phosphor members in a top view so as to expose the surfaces of the phosphor members30in each frame member4. Suitably adjusting the viscosity and the injection amount of the resin material to inject the resin material allows the resin material to wet and spread up to the upper edges of the lateral surfaces of the phosphor members30. The cover member can form a curved recess by the surface tension of the resin material at the upper surface between a kth light emitting element and the (k+1)th light emitting element which are apart by the first distance in each row. The depth (i.e., degree of curvature) of a curved recess formed at the upper surface between a kth light emitting element and the (k+1)th light emitting element in each row can be determined by adjusting the viscosity and the injection amount of the resin. Accordingly, the viscosity and the injection amount of the resin are set by taking into consideration the required thickness of the light shielding members60formed in the subsequent process.

The recesses formed at the upper surface between kth light emitting elements and (k+1)th light emitting elements are continuously formed in the column direction in the form of a groove between the light emitting elements arranged in the kth column and the light emitting elements arranged in the (k+1)th column. The recesses formed between the kth light emitting elements arranged in the kth column and the (k+1)th light emitting elements arranged in the (k+1)th column which are continuously formed over the plurality of rows will hereinafter be referred to as a groove. In the example shown inFIG. 3, grooves each having a curved surface are respectively formed at the surface between the light emitting elements10arranged in the first column and the light emitting elements10arranged in the second column, and between the light emitting elements10arranged in the third column and the light emitting elements10arranged in the fourth column.

Light Shielding Member Disposing Process

In the light shielding member disposing process, light shielding members are disposed in the recesses formed in each row on the upper surface of the cover member between a kth light emitting element and the (k+1)th light emitting element which are apart by the first distance (FIG. 4G). In the case where a groove is formed between a kth column and the (k+1)th column, a continuous strip-shaped light shielding member is disposed in the groove. In disposing a light shielding member in a recess or groove, for example, a dispenser or the like can be used to dispose an uncured resin material that will become the light shielding member in the recess or groove. It is preferable to dispose the light shielding member in a recess or groove such that the ends of the light shielding member closer to the phosphor members30substantially coincide with the edges of the upper surfaces of the phosphor members30. Specifically, in the case of using a resin material for the light shielding member, for example, the viscosity and the injection amount of the resin material to be injected are adjusted such that the ends of the resin material disposed in the recess coincide with the upper edges of the phosphor members30while achieving a thickness that can ensure a predetermined light shielding rate. In the case where a predetermined thickness of the light shielding member can be ensured, the surface of the light shielding member after hardening the resin can be curved downward along the surface of the recess as shown inFIG. 4G. In this case, the viscosity of the resin material to be injected can be set relatively low to allow the injected resin to creep up to the edges of the phosphor members30.

In the case in which the light shielding member needs to have a large thickness, the light shielding member may have a surface that is convex upward. In this case, the viscosity of the resin material to be injected can be set relatively high to allow the edges of the injected resin to stop at the edges of the phosphor members30.

Dividing Process

In the dividing process, individual light emitting devices can be obtained by being split along the cut lines as indicated by the two-dot chain lines inFIG. 3that define the regions that become individual light emitting devices.

Specifically, the dividing process includes cutting of the light shielding member, the cover member, and the substrate in the center of the light emitting elements facing each other which are apart by the first distance D1. In the individual light emitting devices100after being divided, a portion of the cover member50on which the light shielding member60is disposed has a height from the upper surface thereof to the upper surface of the substrate20such that the outer edge side is lower than the phosphor member30side.

A light emitting device of Embodiment 1 can be manufactured by performing the processes descried above.

FIG. 5is a schematic top view of a light emitting device200according to Embodiment 2.FIG. 6is a schematic cross-sectional view taken along line B-B inFIG. 5.FIG. 7is a schematic bottom view of the device shown inFIG. 5. The same members as those in Embodiment 1 are denoted by the same reference numerals.

The light emitting device200of Embodiment 2, as shown inFIGS. 5 and 6, is different from the light emitting device100of Embodiment 1 such that (1) each device has one light emitting element10and one phosphor member, (2) a third electrode28and a fourth electrode29, which are external connection electrodes, are disposed on the lower surface20bof the substrate20, and (3) a frame member is not included.

The light emitting device200of Embodiment 2 will be explained in detail below.

The light emitting device200of Embodiment 2 includes a substrate20, a single light emitting element10disposed on the upper surface20aof the substrate20, and a single phosphor member30. The phosphor member30has a quadrilateral upper surface and a lower surface, and is disposed such that the lower surface faces and covers the light emission surface10aof the light emitting element10.

The light emitting device200of Embodiment 2 includes a cover member50disposed to cover the lateral surfaces of the light emitting element10and the lateral surfaces of the phosphor member30while exposing the upper surface of the phosphor member30, and a light shielding member60disposed on the upper surface of the cover member50along a portion of the perimeter of the upper surface of the phosphor member30.

In the light emitting device200of Embodiment 2 constructed as above, the lateral surfaces of the light emitting element10and the lateral surfaces of the phosphor member30are covered with a cover member50having a high reflectivity similar to the light emitting device100of Embodiment 1. Thus, the light subjected to wavelength conversion by the phosphor member30, or that in combination with a portion of the light emitted by the light emitting element10, exits from the upper surface (i.e., light exiting surface) of the phosphor member30.

In the light emitting device200of Embodiment 2, a light shielding member60is partially disposed on the cover member50along a portion of the perimeter of the upper surface of the phosphor member30. Thus, in the portion on which the light shielding member60is disposed, the exiting light can be sharply reduced as the distance from the light exiting surface increases, and the luminance difference between the light exiting surface and the part where the light shielding member60is disposed can be increased.

As such, in the light emitting device200of Embodiment 2 the light emission at a portion of the perimeter of the light exiting surface can sharply decrease as the distance from the light exiting surface increases, similar to the light emitting device100of Embodiment 1. Accordingly, the light emitting device200of Embodiment 2 allows a relatively simple optical system suitably designed to optically control the light exiting from the light emitting device to achieve a sharp cutoff line.

Furthermore, in the light emitting device200of Embodiment 2, it is preferable to reduce the distances from the phosphor member30to the second, third, and fourth lateral surfaces50c2,50c3, and50c4on the upper surface50aof the cover member50. This can make the boundary of the phosphor member30appear sharp-edged in the vicinity of the second, third, and fourth lateral surfaces50c2,50c3, and50c4. In this case, the thickness of the cover member covering the lateral surfaces of the phosphor member30(i.e., the distance from the phosphor member30to each lateral surface of the cover member in a top view) is preferably set to about 100 μm to about 400 μm. Reducing the thickness of the cover member covering the lateral surfaces of the phosphor member may cause light leakage from the lateral surfaces, but can realize the boundaries along the second, third, and fourth lateral surfaces where the luminance sharply changes on the light emission surface side.

A specific example of the light emitting device of Embodiment 2 will be explained below in detail focusing on the differences from the light emitting device according to Embodiment 1 by using the drawings.

In the light emitting device200of Embodiment 2, the substrate20has a quadrilateral upper surface20aand a lower surface20beach having long sides and short sides. A first electrode26and a second electrode27are disposed on the upper surface20aof the substrate20, and a third electrode28and a fourth electrode29are disposed on the lower surface20bof the substrate20. Interlayer wiring such as vias are provided in the substrate20to connect the first electrode26and the third electrode28, and connect the second electrode27and the fourth electrode29. As shown inFIG. 7, the third electrode28and the fourth electrode29are, for example, substantially quadrilateral, and the light emitting device200is connected to an external circuitry via these electrodes.

In the light emitting device200of Embodiment 2, the light emitting element is disposed on the upper surface20aof the substrate20such that the four sides of the light emission surface10aare in parallel with the corresponding sides of the upper surface20a.

The phosphor member30has a quadrilateral upper surface30aand a lower surface30b, and is disposed such that the lower surface30bfaces and covers the light emission surface10aof the light emitting element10. The upper surface30aand the lower surface30bof the phosphor member30have the same shape, for example, and the phosphor member30is disposed such that all four sides of the lower surface30bare positioned outward of the corresponding sides of the light emission surface10aof the light emitting element10.

The cover member50is disposed to cover the lateral surfaces of the light emitting element10and the lateral surfaces of the phosphor member30while exposing the upper surface of the phosphor member30. The light emitting device200of Embodiment 2 is manufactured by the method described later, for example. The first lateral surface50c1, the second lateral surface50c2, the third lateral surface50c3, and the fourth lateral surface20c4of the cover member50are respectively substantially coplanar with the first lateral surface20c1, the second lateral surface20c2, the third lateral surface20c3, and the fourth lateral surface20c4of the substrate20located immediately thereunder, and the lateral surfaces configure as the outer lateral surfaces of the light emitting device200. Being manufactured by the method described later, the upper surface50aof the cover member50includes a first upper surface50a1and a second upper surface50a2which have different planar directions. In the upper surface50aof the cover member50, the first upper surface50a1is the region between the side of the first lateral surface50c1and the side of the phosphor member30closer to the first lateral surface50c1side, and the second upper surface50a2is the upper surface50aexcluding the first upper surface50a1. Furthermore, in the light emitting device200of Embodiment 2 manufactured by the method described later, the height of the first upper surface50a1from the upper surface20aof the substrate20is lower on the outer edge side (i.e., on the first lateral surface50c1side) than on the phosphor member30side.

The light shielding member60is partially disposed on the first upper surface50a1of the cover member50. The light shielding member60is partially disposed on the upper surface50aof the cover member50along the side of the phosphor member30on the first lateral surface50c1side.

The light emitting device200of Embodiment 2 described above includes a light shielding member disposed on the upper surface50aof the cover member50along the side of the phosphor member30located closer to the first lateral surface50c1side. This can make the boundary in the vicinity along that side of the phosphor member30appear sharp-edged, and when used as the light emitting device in a headlight allows a relatively simple optical system to achieve a sharp cutoff line.

A method of manufacturing a light emitting device of Embodiment 2 will be explained below with reference toFIG. 8andFIGS. 9A to 9G.

FIGS. 9A to 9Gare schematic cross-sectional views each showing a process in the method of manufacturing a light emitting device of Embodiment 2.FIG. 8is a top view of what is shown inFIG. 9F.

The method of manufacturing a light emitting device of Embodiment 2 includes a light emitting element disposing process (FIG. 9B), a protective element disposing process (FIG. 9C), a phosphor member disposing process (FIG. 9D), a frame member disposing process (FIG. 9E), a cover member disposing process (FIG. 9F), a light shielding member disposing process (FIG. 9G), and a dividing process.

InFIG. 8andFIGS. 9A to 9G, the same reference numerals denote the same members before and after the light emitting devices are divided into individual pieces.

Light Emitting Element Disposing Process

In the light emitting element disposing process, a substrate20in a collective state (hereinafter referred to as a substrate block20) is provided (FIG. 9A). On the substrate block20, a plurality (n×m pieces) of light emitting elements are arranged in a matrix of m rows (m is an integer equal to or larger than 1), each row including n pieces (n is an even number equal to or larger than 2). In the present embodiment, in each row, n pieces of light emitting elements are arranged such that the interval between a kth (k is an odd number smaller than n) light emitting element from one end and the (k+1)th light emitting element is a first distance D1. In the example of Embodiment 2 shown inFIG. 8, the interval between the light emitting elements10arranged in the first column (i.e., the column at one end) and the light emitting elements10arranged in the second column, the interval between the light emitting elements10arranged in the third column and the light emitting elements10arranged in the fourth column from that end, and the interval between the light emitting elements10arranged in the fifth column and the light emitting elements10arranged in the sixth column from that end, each have the first distances D1.

In the manufacturing method of Embodiment 2, each light emitting device has a single light emitting element10. Thus, the light emitting elements10in each column are arranged at equal intervals.

Protective element Disposing Process

Subsequently, in the manufacturing method of Embodiment 2, protective elements90are disposed for the light emitting elements10, as needed (FIG. 9C). For example, a protective element90is disposed between a kth light emitting element from one end and the (k+1)th light emitting element in each row. In each row, the protective element90for the kth light emitting element from one end and the protective element90for the (k+1)th light emitting element are disposed next to each other between the kth light emitting element and the (k+1)th light emitting element. In this manner, in each row, a second distance D2between a (k+1)th light emitting element and the (k+2)th light emitting element can be made smaller than the first distance D1between a kth light emitting element and the (k+1)th light emitting element.

Phosphor Member Disposing Process

In the phosphor member disposing process, a phosphor member30is disposed on the light emission surface of each of the light emitting element10provided (FIG. 9D).

Frame Member Disposing Process

In the frame member disposing process, a frame member4surrounding the (n×m) pieces of light emitting elements is disposed on the upper surface of the substrate block20. The method of manufacturing a light emitting device of Embodiment 2 differs from the method of manufacturing a light emitting device of Embodiment 1 in that the frame member4is disposed to collectively surround all of the (n×m) areas which will become individual light emitting devices such that no frame member4remains on the inside of the individual light emitting device areas when divided into individual devices. Similar to Embodiment 1, the frame member4is formed to be lower than the upper surfaces of the phosphor members30as shown inFIG. 9E, for example.

Cover Member Disposing Process

In the cover member disposing process, a cover member is disposed in the area surrounded by the frame member4to cover the lateral surfaces of the (n×m) pieces of light emitting elements and the lateral surfaces of the phosphor members while forming curved recesses at the upper surface between kth light emitting elements and the (k+1)th light emitting elements which are apart by the first distance (FIG. 9F). Methods being the same as or similar to those in Embodiment 1 can be used to dispose the cover member and adjust the depth (degree of curvature) of the curved recesses formed at the upper surface between the kth light emitting elements and the (k+1)th light emitting elements. Accordingly, the viscosity and the injection amount of the resin are set by taking into consideration the required thickness of the light shielding members60formed in the process described later.

Recesses are formed at the upper surface between kth light emitting elements and the (k+1)th light emitting elements in each row also in the case of Embodiment 2. The recesses are normally formed in the shape of a continuous groove between kth columns where kth light emitting elements are arranged and the (k+1)th columns where the (k+1)th light emitting elements are arranged, which result in a continuous groove formed between adjacent light emitting elements. In the example shown inFIG. 8, the curved concave grooves are formed at a surface between the light emitting elements10arranged in the first column (i.e., the column at one end) and the light emitting elements10arranged in the second column, a surface between the light emitting elements10arranged in the third column and the light emitting elements10arranged in the fourth column from that end, and a surface between the light emitting elements10arranged in the fifth column and the light emitting elements10arranged in the sixth column from that end.

Light Shielding Member Disposing Process

In the light shielding member disposing process, in each row, light shielding members are disposed in the curved recesses formed at the upper surface of the cover member between kth light emitting elements and the (k+1)th light emitting elements which are apart by the first distance (FIG. 9G). In the case where a groove-like recess is formed between a kth column and the (k+1)th column, a continuous strip-shape light shielding member is disposed in the groove-like recess. It is also preferable in Embodiment 2 to dispose a light shielding member in a recess or groove-shaped recess such that the edges of the light shielding member substantially coincide with the edges of the phosphor members30. A method being the same or similar to that in Embodiment 1 can be used to dispose a light shielding member in a recess or groove-like recess.

In the case where the light shielding members need to have a large thickness, the surfaces of the light shielding members may be convex upward. In this case, the viscosity of the resin material to be injected is made relatively high to allow the ends of the injected resin stop at the edges of the phosphor members30.

Dividing Process

In the dividing process, individual light emitting devices are separated by being cut along the cut lines indicated by the two-dot chain lines inFIG. 8.

A light emitting device of Embodiment 2 can be manufactured by following the processes described above.

As specifically explained based on Embodiments 1 and 2, a light emitting device according to certain embodiment of the present disclosure includes a light shielding member60partially disposed on the upper surface50aof the cover member50along the side of the phosphor member30closer to the first lateral surface50c1side. This can make the boundary of the phosphor member30appear sharp-edged in the vicinity along that side of the phosphor member30, and when used as the light emitting device for a headlight, a sharp cutoff line can be achieved with a relatively simple optical system.

The light emitting devices and methods of manufacturing the light emitting devices according to the embodiments of the present disclosure described can be modified in various ways as described by the specific descriptions of Embodiments 1 and 2 disclosed.

For example, in a light emitting device according to certain embodiment of the present disclosure, external connection terminals can be disposed on the upper surface20aof the substrate20as described by Embodiment 1, or external connection electrodes can be disposed on the lower surface20bof the substrate20as shown by Embodiment 2.

A light emitting device according to an embodiment of the present disclosure can be structured with a plurality of light emitting elements as shown by Embodiment 1, or a single light emitting element as shown by Embodiment 2.