JP2011035030A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device capable of improving directivity toward an upper part of a light-emitting element of light emitted from the light-emitting element. <P>SOLUTION: The light-emitting device 1 includes a support member 3, the light-emitting element 5 disposed on the support member 3, a light reflector 9 disposed at a side of the light-emitting element 5 on the support member 3, and a translucent member 11 that covers the light-emitting element 5 and the light reflector 9 and is interposed between the light-emitting element 5 and the light reflector 9. The translucent member 11 includes an optical guide part 11a so formed as to project over the light reflector 9. The light reflector 9 includes a reflecting surface 9a for reflecting and guiding the light emitted from the light-emitting element 5 to the light guide part 11a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light emitting device.

  Conventionally, various light-emitting devices having a configuration for increasing the directivity of light emitted from a light-emitting element have been proposed. For example, a surface light source device described in Patent Document 1 includes a light emitting element mounting substrate, a plurality of light emitting elements provided on the light emitting element mounting substrate, and a light emitting element mounting substrate. And a reflector frame body having an opening for arranging the. This surface light source device is intended to emit light above the light emitting element (in the direction opposite to the light emitting element mounting substrate), so that the light emitted to the side of the light emitting element is reflected on the reflector frame. The light is reflected by the reflecting surface that forms the opening, thereby enhancing the directivity upward of the light emitting element.

JP 2007-180524 A

  However, in the surface light source device described in Patent Document 1, there is still reflected light propagating in a direction deviating from the upper side of the light emitting element to the upper side of the light emitting element due to reflection by the reflecting surface of the reflector frame. There was a problem that the directivity was lowered.

  The present invention has been made to solve the above-described problem, and an object thereof is to provide a light-emitting device that can further improve the directivity of light emitted from a light-emitting element to the upper side of the light-emitting element.

  The light emitting device according to the present invention includes a support member, a light emitting element disposed on the support member, a light reflector disposed on a side of the light emitting element on the support member, the light emitting element, and the light. And a translucent member that covers the reflector and is interposed between the light emitting element and the light reflector. The translucent member has a light guide portion formed so as to protrude above the light reflector. The light reflector has a reflecting surface that reflects the light emitted from the light emitting element and guides the light to the light guide portion.

  In the light emitting device configured as described above, it is preferable that a refractive index of the light reflector is smaller than a refractive index of the translucent member.

  A plurality of the light emitting elements may be arranged on the support member.

  The light reflector is preferably formed so as to surround the light emitting element.

  The light emitting elements may be arranged in at least one row on the support member, and the light reflector may be formed along an arrangement direction of the light emitting elements.

  According to the light emitting device of the present invention, the directivity of light emitted from the light emitting element to the upper side of the light emitting element can be further improved.

It is a top view of the light-emitting device concerning one embodiment of the present invention. It is II-II sectional drawing of the light-emitting device of FIG.1 and FIG.3. It is a top view of the light-emitting device concerning one embodiment of the present invention. It is sectional drawing which shows the light-emitting device which concerns on one Embodiment of this invention.

  Hereinafter, an embodiment of a light emitting device according to the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the light emitting device 1 according to the present embodiment includes a support member 3 having a rectangular shape in plan view, a plurality of light emitting elements 5 arranged on the support member 3, and each light emitting element 5. A plurality of connected electrode wirings 7 (7a to 7f) and a light reflector 9 and a light transmissive member 11 provided on the support member 3 are provided.

  The support member 3 has a flat plate shape as shown in FIG. Moreover, the support member 3 is comprised with the material which has electrical insulation, for example, is formed with ceramics, such as an alumina and glass ceramics.

  A plurality (six in the illustrated example) of electrode wirings 7 (7a to 7f) are formed between the support member 3, the light reflector 9, and the translucent member 11. The electrode wirings 7a to 7f extend in a strip shape in the vertical direction of FIG. 1 and are arranged close to each other in a state of being separated from each other in the horizontal direction of FIG. The electrode wirings 7a to 7f are made of, for example, silver or copper. The electrode wirings 7a to 7f are connected to an external drive circuit (not shown) and apply a forward voltage between the anode electrode 17 and the cathode electrode 19 of the light emitting element 5 as will be described later. . As will be described later, the anode wiring 17 in each light emitting element 5 is connected to the electrode wirings 7b, 7d, and 7f among the electrode wirings 7a to 7f, and the electrode wirings 7a, 7c, and 7e among the electrode wirings 7a to 7f. The cathode electrode 19 in each light emitting element 5 is connected.

  As shown in FIG. 1, the plurality of light emitting elements 5 are arranged in a matrix of 5 rows and 5 columns. As shown in FIG. 2, each light-emitting element 5 includes a transparent crystal growth substrate 13 made of sapphire and the like, and an n-type semiconductor layer 15 n and a p-type semiconductor layer 15 p are sequentially stacked on the crystal growth substrate 13. The semiconductor laminated portion 15 formed in this way, the anode electrode 17 connected to the p-type semiconductor layer 15p, and the cathode electrode 19 connected to the n-type semiconductor layer 15n.

  The semiconductor stacked portion 15 has a pn junction region formed by a p-type semiconductor layer 15p and an n-type semiconductor layer 15n, and the pn junction region emits light when a forward current is supplied as will be described later. It is supposed to be. The n-type semiconductor layer 15n and the p-type semiconductor layer 15p are formed, for example, by epitaxially growing a semiconductor such as GaN. In addition, what is necessary is just to comprise this semiconductor laminated part 15 suitably according to a desired light emission wavelength, for example, you may form by III-V group compound semiconductors, such as GaAs and AlGaInP.

  Each light emitting element 5 is connected to the electrode wiring 7 by so-called flip chip connection. More specifically, as shown in FIG. 1, the anode electrode 17 and the cathode electrode 19 in the five light emitting elements 5 in the first column from the left side are the peripheral portion on the left side of the electrode wiring 7 b and the right side of the electrode wiring 7 a, respectively. Connected to the periphery. The anode electrode 17 and the cathode electrode 19 in the five light emitting elements 5 in the second column from the left side are connected to the right peripheral portion of the electrode wiring 7b and the left peripheral portion of the electrode wiring 7c, respectively. The anode electrode 17 and the cathode electrode 19 in the five light emitting elements 5 in the third column from the left are connected to the left peripheral portion of the electrode wiring 7d and the right peripheral portion of the electrode wiring 7c, respectively. The anode electrode 17 and the cathode electrode 19 in the five light emitting elements 5 in the fourth column from the left are connected to the right peripheral portion of the electrode wiring 7d and the left peripheral portion of the electrode wiring 7e, respectively. The anode electrode 17 and the cathode electrode 19 in the five light emitting elements 5 in the fifth column from the left are connected to the left peripheral portion of the electrode wiring 7f and the right peripheral portion of the electrode wiring 7e, respectively. Therefore, by applying a forward voltage between two adjacent electrode wirings among the electrode wirings 7a to 7f, a forward current is supplied to each light emitting element 5 connected between the two electrode wirings. It is possible.

  As shown in FIGS. 1 and 2, the light reflector 9 is provided on the support member 3 so as to sandwich the electrode wirings 7 a to 7 f with the support member 3. As shown in FIG. 1, the light reflector 9 has a plurality of annular portions 9i surrounding each light emitting element 5, and the plurality of annular portions 9i are integrally formed. The light reflector 9 is formed of a material having a refractive index different from that of a light transmitting member 11 described later. For example, a silicon resin, an acrylic resin, a polypropylene resin, or an epoxy is used depending on the material for forming the light transmitting member 11. It can be formed of a resin material such as resin, polyethylene terephthalate resin, polycarbonate resin, polystyrene resin, or optical glass.

  As shown in FIG. 2, each annular portion 9 i of the light reflector 9 has a reflecting surface 9 a disposed on the side of the light emitting element 5. The reflection surface 9a is inclined so as to approach each light emitting element 5 surrounded by each annular portion 9i as it goes toward the support member 3, and reflects the light emitted from each light emitting element 5, thereby transmitting light that will be described later. The light guide portion 11a of the member 11 is guided. In addition, the inclination angle of the reflective surface 9a is set according to the shape and formation position of the light guide part 11a of the translucent member 11 described later.

  As shown in FIGS. 1 and 2, the translucent member 11 covers the light emitting element 5 and the light reflector 9, and is disposed on the support member 3 so as to be interposed between the light emitting element 5 and the light reflector 9. Is provided. The translucent member 11 is formed of a material having a refractive index different from that of the light reflector 9. For example, a silicon resin, an acrylic resin, a polypropylene resin, an epoxy resin, or polyethylene is used depending on the material of the light reflector 9. It can be formed of a resin material such as terephthalate resin, polycarbonate resin, polystyrene resin, or optical glass.

  The translucent member 11 has a light guide portion 11 a formed so as to protrude above the light reflector 9. The light guide portion 11a protrudes upward as shown in FIG. 2, and propagates light guided into the light guide portion 11a by the light reflector 9 upward. In FIG. 1, for convenience of explanation, the light guide portion 11 a of the translucent member 11 is shown as a spotted pattern, and portions other than the light guide portion 11 a of the translucent member 11 are not shown. As shown in FIG. 1, the light guide portion 11a has a plurality of annular bodies 11ai surrounding each light emitting element 5, and the annular bodies 11ai are integrally formed.

  In the light emitting device 1 configured as described above, each of the electrode wirings 7a to 7f is connected to an external drive circuit (not shown), and a forward voltage is applied between the electrode wirings adjacent to the electrode wirings 7a to 7f. A forward current is supplied to the pn junction region in the semiconductor stacked portion 15 of each light emitting element 5, and the pn junction region emits light. The light generated in the pn junction region is emitted radially in all directions. Therefore, as shown in FIG. 2, for example, the light Lu emitted upward from the pn junction region of the light emitting element 5 is emitted to the external space via the crystal growth substrate 13 and the translucent member 11. Further, as shown in FIG. 2, for example, the light Ls1 emitted from the pn junction region of the light emitting element 5 to the side propagates through the translucent member 11 and is reflected by the reflecting surface 9a of the light reflector 9. Guided to the light guide 11a. The light Ls2 guided to the light guide portion 11a propagates upward in the light guide portion 11a. At this time, a part of the light (Ls3) guided to the light guide portion 11a is reflected in the light guide portion 11a and emitted from the light guide portion 11a to above each light emitting element 5.

  Here, in order to efficiently radiate the light emitted from each light emitting element 5 to above each light emitting element 5, in this embodiment, the refractive indexes of the light emitting element 5, the light reflector 9, and the translucent member 11 are the following. It is preferable to set as follows.

  That is, it is preferable that the refractive index of the translucent member 11 is set to a value between the refractive index of the light emitting element 5 and the refractive index of the external atmosphere of the light emitting device 1. By doing so, the refractive index of the translucent member 11 becomes a value close to both the refractive index of the light emitting element 5 and the refractive index of the external atmosphere of the light emitting device 1. Therefore, it is possible to reduce the occurrence of total reflection of light incident on the light transmissive member 11 from the light emitting element 5 and to reduce the occurrence of total reflection of light incident on the external atmosphere of the light emitting device 1 from the light transmissive member 11. . Therefore, it is possible to improve the extraction efficiency of light emitted directly upward from the light emitting element 5. The light emitted upward from the light emitting element 5 is emitted through the crystal growth substrate 13 of the light emitting element 5. Therefore, for example, when the crystal growth substrate 13 is formed of sapphire (refractive index = about 1.8) and the external atmosphere of the light emitting device 1 is air (refractive index = 1.0), the translucent member 11 is made of epoxy. It is good to form with resin (refractive index = about 1.6).

  The refractive index of the light reflector 9 is preferably set to be smaller than the refractive index of the translucent member 11. By doing so, it is possible to easily generate total reflection of light incident on the light reflector 9 from the translucent member 11. Therefore, the light emitted from the light emitting elements 5 to the side can be efficiently guided to the light guide portion 11a. As a result, the light emitted from each light emitting element 5 can be efficiently emitted above each light emitting element 5. be able to. For example, when the translucent member 11 is formed of epoxy resin (refractive index = about 1.6) as described above, the light reflector 9 may be formed of silicon resin (refractive index = about 1.4).

  According to the light emitting device 1 according to the present embodiment, the reflecting surface 9 a of the light reflector 9 is disposed on the side of each light emitting element 5. Therefore, the light radiated to the side of the light emitting element 5 and propagating through the light transmissive member 11 is reflected by the reflection surface 9a of the light reflector 9 and guided to the light guide portion 11a. And since the light guide part 11a is formed so that it may protrude above the light reflector 9, the light guided in the light guide part 11a propagates the inside of the light guide part 11a upward. At this time, a part of the light propagating in the light guide portion 11a is reflected in the light guide portion 11a to change the course, for example, as indicated by an arrow Ls3 in FIG. Are emitted from the upper end of the light guide portion 11a. Therefore, as shown in FIG. 2, the light Ls <b> 2 that still deviated from the upper side of each light emitting element 5 due to the reflection on the reflecting surface 9 a of the light reflector 9 is guided to the upper side of each light emitting element 5. Therefore, the upward directivity of each light emitting element 5 can be improved.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning. For example, in the above-described embodiment, each annular part 9i of the light reflector 9 and each annular part 11ai of the light guide part 11a are formed in a circular shape in plan view as shown in FIG. For example, it may be formed in an arbitrary shape such as a quadrangular shape or a polygonal shape such as a hexagonal shape.

  In addition, the light reflector 9 has a refractive index different from the refractive index of the light transmissive member 11 and is configured to reflect light at the boundary surface between the light reflector 9 and the light transmissive member 11. There is no particular limitation. In the above embodiment, the light reflector 9 is formed of silicon resin or the like. For example, the light reflector 9 is made of air (refractive index = about 1.0) with the formation region of the light reflector 9 as a cavity. It may be configured.

  Further, the shape of the reflection surface 9a of the light reflector 9 is not particularly limited as long as the light emitted to the side of the light emitting element 5 can be guided to the light guide portion 11a of the translucent member 11. Absent. In the above embodiment, as shown in FIG. 2, the reflecting surface 9a is formed in a straight line in a sectional view. For example, the reflecting surface 9a may be curved in a concave shape or bent so as to have a plurality of inclined surfaces. Good.

  Moreover, in the said embodiment, as shown in FIG. 2, although the upper end surface of the light guide part 11a of the translucent member 11 is formed flat, it is not limited to this, For example, it forms in the shape of a convex lens. May be.

  In the light emitting device 1 of the above embodiment, the light emitting elements 5 are arranged in a matrix of 5 rows and 5 columns on the support member 3, but the present invention is not limited to this, and each row and each column is arbitrary. The number of light emitting elements 5 may be arranged. In addition, the arrangement of the plurality of light emitting elements 5 is not limited to a matrix shape, and may be arranged in a staggered manner, or may be arranged in an array of one or more columns.

  Moreover, in the said embodiment, although the one light emitting element 5 is arrange | positioned inside each annular part 9i of the light reflector 9, it is not limited to this, For example, a some light emitting element is arrange | positioned. May be.

  Moreover, in the said embodiment, although each cyclic | annular part 9i and each cyclic | annular body 11ai surrounding each light emitting element 5 are integrated, the light reflector 9 and the light guide part 11a are formed, However, it is not limited to this For example, the light reflector 9 and the light guide portion 11a may be formed by separating the annular portions 9i and the annular bodies 11ai, respectively.

  Moreover, in the light-emitting device 1 of the said embodiment, the light reflector 9 and the translucent member 11 are enclosed so that each light emitting element 5 may be surrounded by each annular part 9i of the light reflector 9, and each annular body 11ai of the light guide part 11a. Although it is formed, as long as the light reflector 9 is disposed on the side of each light emitting element 5 and the light guide portion 11a is formed above the light reflector 9, it is not limited to this. . For example, as shown in FIG. 3, the light reflector 9 may be formed along the arrangement direction of the light emitting elements 5, and the light guide portion 11 a may be formed above the light reflector 9. In FIG. 3, for convenience of explanation, the light guide portion 11 a of the translucent member 11 is shown as a spotted pattern, and portions other than the light guide portion 11 a of the translucent member 11 are not shown. In FIG. 3, the same or similar components as those of the light emitting device 1 shown in FIG. Moreover, the II-II sectional drawing of FIG. 3 is the same as FIG.

  According to the light emitting device 20 shown in FIG. 3, the light reflector 9 is formed along the arrangement direction of the light emitting elements 5. Thereby, the arrangement | positioning space | interval of the light emitting element 5 can be narrowed, and the arrangement density of the arrangement direction of the light emitting element 5 can be made high. Therefore, the light emission intensity per unit area in the arrangement direction of the light emitting elements 5 can be increased.

  In the light emitting device 1 of the above embodiment, a plurality of light emitting elements 5 are arranged on the support member 3. For example, as shown in FIG. 4, a light emitting device 30 in which only one light emitting element 5 is arranged. It may be configured.

  Moreover, in the said embodiment, although the light emitting element 5 was flip-chip connected, it is not limited to this, For example, you may mount face-up using wire bonding.

  Moreover, although the light emitting diode was illustrated as the light emitting element 5 in the said embodiment, it is not limited to this, For example, you may use light emitting elements, such as an organic EL element.

DESCRIPTION OF SYMBOLS 1,20,30 Light-emitting device 3 Support member 3a Base part 5 Light-emitting element 7 (7a-7f) Electrode wiring 9 Light reflector 9a Reflecting surface 11 Translucent member 11a Light guide part

Claims (5)

A support member;
A light emitting device disposed on the support member;
A light reflector disposed on a side of the light emitting element on the support member;
A light-transmitting member that covers the light-emitting element and the light reflector and is interposed between the light-emitting element and the light reflector;
With
The translucent member has a light guide portion formed so as to protrude above the light reflector,
The light reflector has a reflecting surface that reflects light emitted from the light emitting element and guides the light to the light guide portion.   The light emitting device according to claim 1, wherein a refractive index of the light reflector is smaller than a refractive index of the translucent member.   The light emitting device according to claim 1, wherein a plurality of the light emitting elements are arranged on the support member.   The light-emitting device according to claim 1, wherein the light reflector is formed so as to surround the light-emitting element. The light emitting elements are arranged in at least one row on the support member,
The light-emitting device according to claim 3, wherein the light reflector is formed along an arrangement direction of the light-emitting elements.

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