JP2018137256A - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device excellent in light extraction efficiency.SOLUTION: A light emitting device includes: a package 10 including a recess having side faces and a bottom face; a light emitting element 40 mounted on a bottom face 12 of the recess; a plurality of bumps 20 which are arranged on the bottom face around the light emitting element 40 so as to be separated from the light emitting element 40, and each of which includes a ball part 21 and an extension part 22 on the ball part 21, and in top view, an upper part 22a of the extension part being located outside a lower part 22b of the extension part; and a light reflecting resin 30 which is arranged between the bumps 20 and the side faces of the recess and which is also arranged such that the bottom face 12 of the recess between the bumps 20 and the light emitting element 40 is exposed.SELECTED DRAWING: Figure 1C

Description

  The present invention relates to a light emitting device.

2. Description of the Related Art A light emitting device including a light reflecting resin around a light emitting element placed inside a recess of a package is known. The light reflecting resin is blocked by a lead frame formed on the bottom surface of the recess or a frame body made of resin, so that the side surface of the light emitting element is not covered.
(For example, patent document 1).

JP 2005-136378 A

  Depending on the purpose and application, the number of light-emitting elements placed in the same package may be changed. Moreover, even if the number of light emitting elements is the same, the position and shape where the optimal light reflecting resin is disposed may be different. In such a case, if it is set as the structure disclosed by the prior art document 1, it is necessary to change the metal mold | die for resin molding, and the shape of a lead frame, and a big effort and cost start.

The present embodiment includes the following configuration.
A package having a recess having a side surface and a bottom surface; a light emitting element mounted on the bottom surface of the recess; and a light emitting element disposed on a bottom surface around the light emitting element so as to be separated from the light emitting element. A plurality of bumps each including an extending portion, wherein the upper portion of the extending portion is positioned outside the lower portion of the extending portion, and the bump is disposed between the bump and the side surface of the recessed portion when viewed from above; And a light reflecting resin disposed so that a bottom surface of the recess between the light emitting element and the light emitting element is exposed.

  As described above, the formation region of the light reflecting resin can be easily defined, and the light extraction efficiency is improved.

FIG. 1A is a schematic top view of the light emitting device according to the embodiment. 1B is a schematic cross-sectional view taken along line 1B-1B in FIG. 1A. FIG. 1C is an enlarged view of a portion 1C of FIG. 1B.

  A mode for carrying out the present invention will be described below with reference to the drawings. However, the form shown below illustrates the light-emitting device for embodying the technical idea of the present invention, and the present invention does not limit the light-emitting device to the following.

  Further, the present specification by no means specifies the member shown in the claims as the member of the embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the present invention only to the embodiments unless specifically described. It should be noted that the size and positional relationship of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate.

  1A to 1C show a light emitting device 100 according to an embodiment. The light emitting device 100 includes a package 10, a light emitting element 40, a bump 20, and a light reflecting resin 30 as main components. Hereinafter, each configuration will be described in detail.

(package)
For example, the package 10 may be a package 10 having a quadrangular shape when viewed from above as shown in FIG. 1A. The shape, size, thickness and the like of the package 10 are not particularly limited, and a known package can be used. The package 10 includes a recess 13 having a side surface 11 and a bottom surface 12. For example, as shown in FIG. 1A, the opening can include a concave portion 13 having a square shape. The shape of the recess 13 is not particularly limited. A conductive member (not shown) for energizing the light emitting element 40 is provided on the bottom surface 12 of the recess 13.

  As such a package 10, for example, a resin package in which a metal member is integrally held with a molding resin can be used. Alternatively, a known package such as a ceramic package including a ceramic and a wiring, or a glass epoxy package including a glass epoxy resin and a wiring can be used.

(Light emitting element)
The light emitting element 40 is placed on the bottom surface 12 of the recess 13 of the package 10. Specifically, the light emitting element 40 is placed on the bottom surface 12 of the recess 13 via the bonding member 50. The light emitting element 40 includes a stacked structure including a semiconductor layer, a p-electrode, and an n-electrode, and a known semiconductor light-emitting element can be used. For example, a group III-V compound semiconductor including a nitride semiconductor such as InN, AlN, GaN, InGaN, AlGaN, InGaAlN, or a group II-VI compound semiconductor can be given. These laminated structures include a light emitting layer. Moreover, the laminated structure may include a light-transmitting substrate. A sapphire is mentioned as a translucent board | substrate. The laminated structure may have a polygonal shape such as a triangle, a quadrangle, a pentagon, and a hexagon in a top view, or a shape in which some of these are missing. In the light emitting element 40, the p electrode and the n electrode are electrically connected to the conductive member of the package 10 by a wire or the like.

(bump)
The bump 20 is disposed on the bottom surface 12 around the light emitting element 40 so as to be separated from the light emitting element 40. The bump 20 is used as a member for blocking the light reflecting resin 30. The bump 20 is disposed on the bottom surface 12 of the recess 13 of the package 10. A plurality of the bumps 20 are disposed on the bottom surface 12 around the light emitting element 40 so as to be separated from the light emitting element 40. Each bump 20 includes a ball portion 21 and an extending portion 22 on the ball portion 21.

  The bump 20 is formed as follows. First, an initial ball is formed by melting the tip of a wire inserted through a capillary and held by a wire clamp by electric discharge or the like. Conditions such as electric discharge can be appropriately selected according to the wire composition, diameter, target initial ball size, and the like. The initial ball is brought into contact with the bottom surface 12 of the recess 13 of the package 10 and is subjected to pressure connection by applying heat and ultrasonic waves. As a result, the initial ball becomes the ball portion 21. FIG. 1A illustrates the bump 20 whose top view shape is an elliptical shape having a major axis in the left-right direction by setting the direction of ultrasonic vibration to one direction (left-right direction in FIG. 1A). Note that the top view shape of the bump 20 may be circular.

  Next, the capillary is raised with the wire clamp open, and the wire clamp is closed and the wire is clamped at the raised position. And a wire is cut | disconnected by raising a capillary in the state which clamped the wire with the wire clamp. Specifically, after moving the capillary directly above the ball portion, the capillary is moved in the lateral direction opposite to the light emitting element, and is moved immediately above that position. Thereby, the extending part 22 extending in an oblique direction from the ball part 21 is formed. That is, the upper part 22 a of the extending part 22 is not located immediately above the lower part 22 b of the extending part 22 but is located outside the lower part 22 b of the extending part 22. Thus, by extending the extending portion 22 outward, the spread of the light reflecting resin 30 described later can be efficiently suppressed.

  The distance between the center of the bump 20 and the light emitting element 40 (side surface of the light emitting element 40) can be, for example, about 80 μm to 500 μm. FIG. 1A illustrates bumps 20 arranged in a rectangular shape around a light emitting element 40 having a square shape when viewed from above. The bumps 20 are preferably arranged along the light emitting element 40. For example, the bumps 20 may be arranged in a square shape around the light emitting element 40 whose top view shape is square.

  As for the thickness of the ball portion 21, for example, the thickness of the thickest portion can be set to about 1 μm to 15 μm. Further, as shown in FIG. 1A, the ball portion 21 on the side (inner side) close to the light emitting element 40 can be made thinner than the ball portion 21 on the side away from the light emitting element 40 (outer side). Thereby, the light from the light emitting element 40 can be easily reflected upward. The ball portion 21 having such a shape can be formed by deforming the ball portion 21 closer to the light emitting element 40 by pressing it with a capillary. Such deformation may be performed for each bump 20 or a plurality of bumps 20 may be deformed collectively. The diameter of the ball | bowl part 21 can be about 30 micrometers-150 micrometers, for example. When the ball portion has an elliptical shape, for example, the major axis can be about 30 μm to 150 μm and the minor axis can be about 20 μm to 140 μm.

  The extending portion 22 can have a height of the upper portion 22 a of, for example, about 15 μm to 50 μm from the bottom surface 12 of the package 10. In addition, the height of the upper portion 22 a of the extending portion 22 is preferably made smaller than the thickness of the bonding member 50 for fixing the light emitting element 40 to the package 10. Thereby, the light from the light emitting element 40 can be easily reflected by the light reflecting resin 30. In addition, the joining member 50 may crawl up to the side surface of the light emitting element 40. In this case, the upper portion 22a of the extending portion 22 is located at a position lower than the thickness of the joining member 50 directly below the light emitting element 40. It is preferable to do so.

  The length of the extending portion 22 (distance from the upper portion 22a to the lower portion 22b) can be set to about 10 μm to 50 μm, for example. Further, the upper portion 22 a of the extending portion 22 is preferably located inside the outer periphery of the ball portion 21. The extending portion 22 can be inclined at an angle of 30 to 90 degrees with respect to the bottom surface 12. In addition, the direction in which the extending portion 22 is inclined is preferably on a straight line connecting the center of the light emitting element 40 and the center of each bump 20 in a top view, and is inclined in a direction away from the light emitting element 40.

  Each bump 20 is preferably in contact with the adjacent bump 20 as shown in FIG. 1A.

  Examples of the material of the bump 20 include Au, Al, and Ag.

(Light reflecting resin)
The light reflecting resin 30 is disposed on the bottom surface 12 between the side surface 11 of the recess 13 of the package 10 and the bump 20. The light reflecting resin 30 can be formed by supplying and curing the liquid light reflecting resin 30 using a dispense nozzle or the like. Since the liquid light reflecting resin 30 is blocked by the bumps 20, it is formed so as not to contact the light emitting element 40. In other words, the light reflecting resin 30 is disposed so that the bottom surface 12 of the recess 13 between the bump 20 and the light emitting element 40 is exposed. Thereby, the light from the light emitting element 40 can be reflected efficiently.

As a material constituting the light reflecting resin 30, a member that hardly absorbs light from the light emitting element and efficiently reflects is preferable. The specific reflectance is preferably at least 50% or more, more preferably 70% or more. Further, an insulating member is preferable, and a member that is not easily deteriorated by light from the light emitting element or external light is preferable. Moreover, it has a certain amount of strength, and a thermosetting resin, a thermoplastic resin, or the like can be used, and more specifically, a phenol resin, a glass epoxy resin, a BT resin, a PPA, a silicone resin, or the like can be given. By adding a reflective member (for example, TiO ₂ , Al ₂ O ₃ , ZrO ₂ , MgO, ZnO) or the like that reflects light from the light-emitting element to the base resin, light can be efficiently reflected. .

(Sealing member)
As a material of the sealing member, a material having translucency capable of transmitting light from the light emitting element and light resistance is preferable. Specific examples of the material include a silicone resin composition, a modified silicone resin composition, an epoxy resin composition, a modified epoxy resin composition, and an acrylic resin composition, which have a light-transmitting property capable of transmitting light from a light-emitting element. An insulating resin composition can be mentioned. In addition, a silicone resin, an epoxy resin, a urea resin, a fluororesin, and a hybrid resin containing at least one of these resins can be used. In addition to such materials, a colorant, a light diffusing agent, a light reflecting material, various fillers, a wavelength conversion member (phosphor), and the like can be included as desired.

Examples of the phosphor include oxide-based, sulfide-based, and nitride-based phosphors. For example, when a gallium nitride-based light emitting device that emits blue light is used as the light emitting device, a YAG system that absorbs blue light to emit yellow to green light, a LAG system, a SiAlON system that emits green light (β sialon), a SCASN that emits red light, At least one or more of CASN type, KSF type phosphor (K ₂ SiF ₆ : Mn), sulfide type phosphor, nanophosphor, etc. can be used.

(Joining member)
The bonding member 50 is a member for fixing the light emitting element 40 to the package 10. As the bonding member, either an insulating bonding member or a conductive bonding member can be used. Examples of insulating adhesives include epoxy resins and silicone resins. Examples of conductive adhesives include conductive pastes such as silver, gold, and palladium, and Au—Sn eutectic Sn—Ag—Cu. Examples thereof include solder materials, brazing materials such as low melting point metals, Cu, Ag, and Au.

  The light-emitting device according to the embodiment of the present invention is used in a wide range of applications such as various display devices, lighting fixtures, displays, backlight light sources of liquid crystal displays, and image reading devices and projector devices in facsimiles, copiers, scanners, and the like. Can be used.

DESCRIPTION OF SYMBOLS 100 ... Light-emitting device 10 ... Package 11 ... Side surface 12 ... Bottom surface 13 ... Concave 20 ... Bump 21 ... Ball part 22 ... Stretching part 22a ... Upper part of extending part 22b ... Lower part of extending part 30 ... Light reflecting resin 40 ... Light emitting element 50 ... Joining member 60 ... sealing member

Claims (6)

A package with a recess having a side and a bottom;
A light emitting device placed on the bottom surface of the recess;
A plurality of bumps disposed on the bottom surface around the light emitting element so as to be separated from the light emitting element, and including a ball portion and an extending portion on the ball portion, and an upper portion of the extending portion in a top view The bumps located outside the lower portion of the extending portion;
A light reflecting resin disposed between the bump and the side surface of the recess, and disposed so that the bottom surface of the recess between the bump and the light emitting element is exposed;
A light emitting device comprising:   The light emitting device according to claim 1, wherein a distance between the bump and the light emitting element is 80 μm to 500 μm.   3. The light emitting device according to claim 1, wherein a height of an upper portion of the extending portion is located from 15 μm to 50 μm from the bottom surface of the concave portion.   The said light emitting element is being fixed to the said bottom face of the said recessed part via the joining member, The height of the upper part of the said extending | stretching part is smaller than the thickness of the said joining member. The light emitting device according to one item.   The light emitting device according to claim 1, wherein a length of the extending portion is 10 μm to 50 μm.   6. The ball portion according to claim 1, wherein a height of the ball portion on a side close to the light emitting element is thinner than a height of the ball portion on a side away from the light emitting element. The light-emitting device of description.

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