JP6920618B2 - Light emitting device - Google Patents

Description

The present disclosure relates to a light emitting device.

In general, a light emitting device using a light emitting element such as a light emitting diode is widely used as various light sources such as a lighting fixture. As such a light emitting device, for example, there is a light emitting device including a plurality of light emitting elements, a phosphor, and a package in which a current is individually applied to each light emitting element (for example, Patent Document 1). In such a light emitting device, the light emitted from the light emitting device can be set to a desired light emitting color by adjusting the light emitting intensity of each light emitting element.

JP 2013-120812

However, it is difficult for the light emitting device of Patent Document 1 to emit light having a wide range of chromaticities as the light emitting color.

Therefore, in one embodiment of the present invention, it is an object of the present invention to provide a light emitting device capable of emitting light having a wide range of chromaticities as a light emitting color.

The light emitting device according to the embodiment of the present invention covers the first light emitting element and the second light emitting element, each of which has a light emitting peak wavelength of 430 nm to 480 nm, the first light emitting element and the second light emitting element, and is a first phosphor. The first light emitting element and the second light emitting element can be driven independently, and the sealing member has a convex portion on a part of the upper surface thereof and below the convex portion. The first light emitting element is located in a certain first region, the second light emitting element is located in a second region located below the upper surface of the sealing member and at a position different from the first region.
Further, another light emitting device according to the embodiment of the present invention covers the first light emitting element and the second light emitting element, and the first light emitting element and the second light emitting element, respectively, having a light emitting peak wavelength of 430 nm to 480 nm. A sealing member containing a first phosphor is provided, and the first light emitting element and the second light emitting element can be driven independently, and the sealing member is a recessed portion that is recessed downward in a part of the upper surface. The second light emitting element is located in the third region below the recessed portion, and the first light emitting element is located in the fourth region located below the upper surface of the sealing member and at a position different from the third region. The element is located.

According to one embodiment of the present invention, it is possible to provide a light emitting device capable of emitting light having a wide range of chromaticities as a light emitting color.

It is a schematic top view of the light emitting device which concerns on 1st Embodiment. It is a schematic bottom view of the light emitting device which concerns on 1st Embodiment. It is a schematic end view in line 1C-1C in FIG. 1A. It is a schematic top view which shows an example of a package. It is a schematic top view which shows an example of a package. It is a schematic end view in line 2B-2B in FIG. 2A. It is a schematic top view which shows an example of a light emitting device. It is a schematic end view in 3B-3B in FIG. 3A. It is a schematic end view of the light emitting device which concerns on one modification of 1st Embodiment. It is a schematic end view of the light emitting device which concerns on one modification of 1st Embodiment. It is a schematic end view of the light emitting device which concerns on one modification of 1st Embodiment. It is a schematic top view of the light emitting device which concerns on 2nd Embodiment. It is a schematic end view at line 5B-5B in FIG. 5A.

Hereinafter, a detailed description will be given based on the drawings. The parts having the same reference numerals appearing in a plurality of drawings indicate the same or equivalent parts or members.
Further, the following is an example of a light emitting device for embodying the technical idea of the present invention, and the present invention is not limited to the following. Unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components are not intended to limit the scope of the present invention to that alone, but are intended to be exemplified. Also, in the following description, terms indicating a specific direction or position (for example, "top", "bottom" and other terms including those terms) may be used. These terms use relative orientation or position in the referenced drawings for clarity only. The size and positional relationship of the members shown in each drawing may be exaggerated for ease of understanding. The relationship between the color name and the chromaticity coordinate, the relationship between the wavelength range of light and the color name of monochromatic light, and the like are in accordance with JIS Z8110.

In the present specification and in the drawings, the X direction indicates a lateral direction and includes both _{a right direction (X +} direction) and a left direction (X _{− direction).} Further, the Y direction indicates a vertical direction, and includes both _{an upward direction (Y +} direction) and a downward direction (Y _{− direction).}

Further, in the following description of the embodiment, the terms such as "package" may be used before and after the provision of the light emitting element, the wire, and the like.

(First Embodiment)
1A is a schematic top view of the light emitting device 100 according to the first embodiment, FIG. 1B is a schematic bottom view of the light emitting device 100, and FIG. 1C is a schematic end view taken along line 1C-1C in FIG. 1A. Is. In FIG. 1A, the sealing member 40 is omitted so that the inside of the recess 2 can be easily seen. The light emitting device 100 includes a first light emitting element 10 and a second light emitting element 20, and a sealing member 40 that covers the first light emitting element 10 and the second light emitting element 20 and includes a first phosphor 61. The light emitting device 100 according to the first embodiment further includes a package 1 having a recess 2, and the first light emitting element 10 and the second light emitting element 20 are arranged on the bottom surface of the recess 2.

Package 1 is a base for arranging the first light emitting element 10 and the second light emitting element 20. Package 1 includes a plurality of leads 50 including a first lead 51, a second lead 52, and a third lead 53, and a resin portion 30 integrally formed with the plurality of leads 50. Further, the package 1 has a recess 2, and a part of the upper surface of the first lead 51, the second lead 52, and the third lead 53 is located on the bottom surface of the recess 2.

Package 1 shown in FIGS. 1A and 1B has a top surface 80 and a bottom surface 81 located opposite the top surface 80. Further, the package 1 has a substantially rectangular outer shape in a top view, and has a first outer surface 82, a second outer surface 83 located on the opposite side of the first outer surface 82, a third outer surface 84, and a third outer surface 82. It has a fourth outer surface 85 located on the opposite side of the outer side surface 84. The plurality of leads 50 are exposed from the resin portion 30 on the outer surface and are substantially on the same surface as the resin portion 30. As described above, by preventing the plurality of leads 50 from extending outward from the resin portion 30 on the outer surface, it is possible to provide a small light emitting device 100 having a small occupied area.

The lower surface 81 of the package 1 functions as a mounting surface for mounting the light emitting device 100 on the mounting board. Further, on the lower surface 81 of the package 1, the first lead 51, the second lead 52, and the third lead 53 are exposed from the resin portion 30. As a result, the heat generated from the first light emitting element 10 and the second light emitting element 20 can be efficiently dissipated from the lower surface 81 of the package 1. Further, on the lower surface 81 of the package 1, the lower surfaces of the plurality of leads 50 and the lower surface of the resin portion 30 are formed on substantially the same surface.

The first light emitting element 10 and the second light emitting element 20 function as a light source of the light emitting device 100, and further serve as an excitation source for a phosphor, which will be described later. The first light emitting element 10 and the second light emitting element 20 have an emission peak wavelength of 430 nm to 480 nm. Since the first light emitting element 10 and the second light emitting element 20 have an emission peak wavelength having a wavelength longer than that in the near-ultraviolet region, there is a problem of light in the near-ultraviolet region (for example, it adversely affects the human body or an irradiated object, or emits light. It is possible to suppress the problem that the constituent members of the device are deteriorated and the luminous efficiency of the light emitting device is significantly lowered).

The first light emitting element 10 and the second light emitting element 20 are connected in parallel. As a result, the current values flowing through the first light emitting element 10 and the second light emitting element 20 can be driven differently. By making the current values flowing through the first light emitting element 10 and the second light emitting element 20 different, the chromaticity of the light emitted above each light emitting element can be easily made different.

In the light emitting device 100 shown in FIG. 1A, the first light emitting element 10 and the second light emitting element 20 are arranged on the upper surface of the first lead 51. The first light emitting element 10 has positive and negative electrodes on the upper surface, one electrode is connected to the second lead 52 by a wire, and the other electrode is connected to the first lead 51 by a wire. Similarly, the second light emitting element 20 has positive and negative electrodes on the upper surface, one electrode is connected to the third lead 53 by a wire, and the other electrode is connected to the first lead 51 by a wire. In this way, when the light emitting device 100 includes three leads, each light emitting element can be driven independently. Further, by setting the plurality of leads 50 to the minimum number of leads that enable independent drive, it is possible to reduce the interface between the plurality of leads 50 and the package 1 formed by the resin portion 30. As a result, it is possible to suppress a decrease in the strength of the light emitting device.

It is preferable that the first light emitting element 10 and the second light emitting element 20 do not have a partition member such as a wall arranged between them. Thereby, the color mixing property of the light emitting device 100 can be improved. Specifically, in the light emitting device 100 shown in FIG. 1A, the first light emitting element 10 and the second light emitting element 20 are arranged in one accommodating portion (inside the recess 2), and the first light emitting element 10 and the second light emitting element are arranged. No partition member such as a wall is arranged between the 20 and the 20. As a result, the light in the vicinity of the first light emitting element 10 and the light in the vicinity of the second light emitting element 20 are easily mixed, and a light emitting device having excellent color mixing properties can be obtained. A partition member such as a wall may be arranged between the first light emitting element 10 and the second light emitting element 20.

In the light emitting device 100 shown in FIG. 1A, the first light emitting element 10 and the second light emitting element 20 are arranged apart from each other in the top view. It is preferable that the center of the first light emitting element 10 is displaced from the center of the second light emitting element 20 in both the X direction and the Y direction in the top view. In other words, the shortest distance from the first outer surface 82 of the package 1 to the center of the first light emitting element 10 is different from the shortest distance from the first outer surface 82 to the center of the second light emitting element 20, and the third It is preferable that the shortest distance from the outer side surface 84 to the center of the first light emitting element 10 and the shortest distance from the third outer surface 84 to the center of the second light emitting element 20 are different. By arranging the first light emitting element 10 and the second light emitting element 20 so as to be offset from each other in the top view, the ratio of the light emitted by one light emitting element absorbed by the other light emitting element can be reduced, and the light extraction is good. It can be a light emitting device.

The sealing member 40 covers the first light emitting element 10 and the second light emitting element 20. In the light emitting device 100 shown in FIG. 1G, the sealing member 40 is located in the recess 2 and covers the upper surface and the side surface of the first light emitting element 10 and the upper surface and the side surface of the second light emitting element 20.

The sealing member 40 contains the first phosphor 61. The first phosphor 61 may be one type of phosphor or a plurality of types of phosphors. By using a plurality of types of phosphors, the color rendering property of the light emitting device 100 can be improved. The first phosphor 61 includes, for example, a phosphor having a composition represented by the following formula (1) and a phosphor having a composition represented by the following formula (2).
(Y, Lu, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce (1)
(Sr, Ca) AlSiN ₃ : Eu (2)

The sealing member 40 has a convex portion 3 on a part of the upper surface. Further, the first light emitting element 10 is located in the first region 9a below the convex portion 3. In other words, the convex portion 3 is located above the first light emitting element 10. Further, the second light emitting element 20 is located in the second region 9b located below the upper surface of the sealing member 40. In FIG. 1G, both the first region 9a and the second region 9b are on the upper surfaces of the plurality of leads 50 and are located in different regions from each other. By providing the convex portion 3 above the first light emitting element 10, the volume of the sealing member 40 located above the first light emitting element 10 is changed to the volume of the sealing member 40 located above the second light emitting element 20. Can be made larger more easily. As a result, the amount of the first phosphor 61 located above the first light emitting element 10 can be made larger than the amount of the first phosphor 61 located above the second light emitting element 20, and as a result, Of the light emitted above the sealing member 40, the chromaticity of the light emitted above the first light emitting element 10 and the chromaticity of the light emitted above the second light emitting element 20 can be easily made different.

The chromaticity of light on the 1931CIE chromaticity diagram generally tends to increase the x value of the chromaticity when there are many red components. Therefore, for example, when a yellow to red phosphor is used as the first phosphor 61, the x value of the chromaticity of the light emitted above the first light emitting element 10 is the color of the light emitted above the second light emitting element 20. Greater than the x value of degree. Since the light emitting device 100 has the convex portion 3 above the first light emitting element 10, the x value of the chromaticity of the light emitted above the first light emitting element 10 is the color of the light emitted above the second light emitting element 20. It can be made larger than the x value of the degree. As a result, it becomes possible to provide a light emitting device capable of emitting light having a wide range of chromaticities as a light emitting color.

In the present specification, the chromaticity of the light emitted above the first light emitting element 10 can be, for example, the chromaticity of the light emitting device 100 when only the first light emitting element 10 is driven. Similarly, the chromaticity of the light emitted above the second light emitting element 20 can be, for example, the chromaticity of the light emitting device 100 when only the second light emitting element 20 is driven.

It is preferable that the convex portion 3 is positioned so that the geometric center of the convex portion 3 substantially coincides with the center of the first light emitting element 10 in the top view. As a result, the optical axis of the first light emitting element 10 and the optical axis of the convex portion 3 can be aligned with each other, so that the light from the first light emitting element 10 can be efficiently taken out to the outside. Further, all of the first light emitting element 10 can be located below the convex portion 3, and only a part of the first light emitting element 10 can be located below the convex portion 3. When all of the first light emitting elements 10 are located below the convex portion 3, the maximum width of the convex portion 3 in the top view is preferably substantially the same as the maximum width of the first light emitting element 10 in the top view. As a result, the emitted light emitted upward from the first light emitting element 10 can be efficiently taken out to the outside, and the ratio of the emitted light from the adjacent second light emitting element 20 incident on the convex portion 3 is reduced. This makes it possible to efficiently change the chromaticity of the emitted light emitted above the first light emitting element 10 and the second light emitting element 20. Second light emitting element 20. The maximum width of the convex portion 3 in top view is, for example, 300 to 1000 μm. Further, the distance between the lowest portion and the highest portion of the convex portion 3 in the height direction is, for example, 150 to 500 μm.

The convex portion 3 can be formed at the same time when the sealing member 40 is formed by the mold, and after the first sealing member is provided in the concave portion 2, the first phosphor is formed by a potting method or the like. A second sealing member including 61 can be provided in a separate step.

When only the first light emitting element 10 is driven, the light emitting device 100 can emit light having a color temperature of 1800 to 5000 K, for example. Further, the light emitting device 100 is set higher than the color temperature when only the second light emitting element 20 is driven, for example, when only the first light emitting element 10 is driven, and emits light having a color temperature of 3500 to 7000K. It is possible. Further, the light emitting device 100 can emit light of a light emitting color having a color temperature of 1800 to 7000K by adjusting the current value to be passed through each of the first light emitting element 10 and the second light emitting element 20. As a result, it is possible to make a light emitting device capable of emitting light having a wide correlation color temperature as a light emitting color.

Hereinafter, each member used in the light emitting device 100 of the present invention will be described in detail.

(package)
Package 1 is a base for arranging light emitting elements. Package 1 has at least a mother body and a plurality of leads (a plurality of electrode portions). The base material of the package 1 is, for example, ceramics such as aluminum oxide and aluminum nitride, and resins (for example, silicone resin, silicone-modified resin, epoxy resin, epoxy-modified resin, unsaturated polyester resin, phenol resin, polycarbonate resin, acrylic). Resin, trimethylpentene resin, polynorbornene resin, hybrid resin containing one or more of these resins, etc.), pulp, glass, or a composite material thereof. The base body of the package 1 may have a single-layer structure or a multi-layer structure including a plurality of layers.

As an example of the package 1, a package including the resin portion 30 and the plurality of leads 50 used in the light emitting device 100 of FIG. 1A can be preferably used. As a result, it is possible to obtain an inexpensive light emitting device having high heat dissipation. In the light emitting device 100 shown in FIG. 1A, the plurality of leads 50 do not extend outward from the resin portion 30 on the outer surface of the package 1, but the light emitting device of the present embodiment is not limited to this. That is, on the outer surface of the package 1, the plurality of leads 50 may extend outward from the resin portion 30. As a result, the heat generated by the light emitting element can be efficiently dissipated to the outside.

FIG. 1D shows a modified example of the package 1. In FIG. 1D, the area where the light emitting element, the protective element, and the wire are arranged is shown by a broken line. Package 1 shown in FIG. 1D includes a first lead 51, a second lead 52, a third lead 53, and a fourth lead 54. The first light emitting element 10 is arranged on the upper surface of the first lead 51, and the second light emitting element 20 is arranged on the upper surface of the second lead. One of the positive and negative electrodes (not shown) of the first light emitting element 10 is connected to the first lead 51 by a wire, and the other electrode is connected to the third lead 53 by a wire. Further, one of the positive and negative electrodes (not shown) of the second light emitting element 20 is connected to the second lead 52 by a wire, and the other electrode is connected to the fourth lead 54 by a wire. As a result, the conductive path of the first light emitting element 10 (first lead 51 and third lead 53) and the conductive path of the second light emitting element 20 (second lead 52 and fourth lead 54) can be completely separated. can. As a result, the current value flowing through each of the first light emitting element 10 and the second light emitting element 20 can be adjusted with a high degree of freedom.

The package 1 shown in FIG. 1D has a protrusion 13a on a part of the side wall of the recess 2. The protruding portion 13a has a shape that protrudes from the outer surface of the package 1 toward the inside of the package 1. The protrusion 13a is preferably formed so as to straddle at least two leads out of the plurality of leads 50. As a result, the strength between at least two leads is increased, and the strength of the package 1 is improved. In the package 1 shown in FIG. 1D, the protruding portion 13a is formed so as to straddle between the first lead 51 and the second lead 52. Thereby, the strength of the package 1 can be improved. Further, in the package 1, when the separation region of each lead is formed in a straight line from the side wall of the recess 2 to the opposite side wall, the strength of the package 1 may be low. In such a package, by arranging the protruding portion 13a on the extension line of the separation region of each lead, it is possible to suppress a decrease in the strength of the package 1. In the package 1 shown in FIG. 1D, the protruding portion 13a is formed on a straight line in the separation region between the first lead 51 and the second lead 52 and the separation region between the third lead 53 and the fourth lead 54. Thereby, the strength of the package 1 can be effectively improved.

In the direction X1 along the side wall 6 having the protrusion 13a, the width of the protrusion 13a on the bottom surface of the recess 2 may be larger than the distance between the leads (the distance between the first lead 51 and the second lead 52). preferable. As a result, the protruding portion 13a can be arranged across the plurality of leads, so that the decrease in the strength of the package 1 can be suppressed. Further, the width of the protruding portion 13a on the bottom surface of the recess 2 may be larger than the separation distance between the first light emitting element 10 and the second light emitting element 20. Further, the width of the protruding portion 13a on the bottom surface of the recess 2 can be made larger than the width of the protruding portion 13a on the opening. As a result, when the convex portion 9 is formed by mold molding, the mold can be easily released and it is possible to prevent a part of the convex portion 9 from being chipped. In the direction X1, the maximum width of the protruding portion 13a is, for example, 0.05 times to 1 times, preferably 0.1 times to 0.3 times, the width of the side wall 6. Further, in the package 1 shown in FIG. 1D, on the upper surface of the package 1, the upper surface of the protruding portion 13a is substantially the same as the upper surface of the other resin portions 30. Thereby, the protruding portion 13a can be easily visually recognized in the top view, and for example, the protruding portion 13a can have a function as a recognition target portion indicating the polarities of the plurality of leads 50.

In the direction Y1 in the direction perpendicular to the direction X1, the protruding portion 13a on the bottom surface of the recess 2 is preferably located closer to the side wall 6 side than the connecting portion P between the wire and the lead extending from the light emitting element. As a result, a wide area for connecting the wires can be secured, and the connections of the wires become easy. In the direction Y1, the protruding portion 13a on the bottom surface of the recess 2 may be located farther from the side wall 6 than the connecting portion P between the wire and the lead extending from the light emitting element.

The protrusion 13a can have a shape that is line-symmetric with respect to a line passing through the center of the separation region between the leads in a top view. As a result, when stress is applied to the package 1 from the outside, it is possible to prevent the stress from concentrating on only one lead. As a result, deformation of the package 1 and the like can be suppressed.

The number of protruding portions 13a may be one, or two or more may be provided. For example, the convex portion 9 may be formed so as to straddle between the third lead 53 and the fourth lead 54, or may be formed so as to straddle between the first lead 51 and the third lead 53. It may be formed so as to straddle between the two leads 52 and the fourth lead 54.

Further, the package 1 preferably has a recessed portion 13b on the side wall of the recessed portion 2. Since the package 1 has the recessed portion 13b, the adhesion strength between the package 1 and the sealing member 40 is improved. Further, by connecting one end of the wire connected to the light emitting element or the protective element to the vicinity of the recessed portion 13b, a large area for connecting the wire can be secured. This makes it possible to reduce the possibility of wire connection failure.

The outer shape of the package 1 and the opening shape of the recess 2 can be rectangular, other polygonal, circular, elliptical, or the like when viewed from above. Further, as shown in FIG. 1A, the opening shape of the recess 2 can be partially deformed by chamfering one corner of the rectangular opening of the recess 2 in the top view. As a result, a part of the opening can function as a mark indicating the polarity of the lead such as an anode mark or a cathode mark.

As another example of the package 1, as shown in FIGS. 2A and 2B, the package 1 has a flat plate-shaped substrate 7 and a frame-shaped resin portion 30 made of a light-reflecting resin provided on the upper surface of the substrate 7. Packages can be used. FIG. 2A is a schematic top view of the package 1, and FIG. 2B is a schematic end view taken along line 2B-2B in FIG. 2A. In FIG. 2A, the sealing member is omitted. The frame-shaped resin portion 30 has a role as a reflector for reflecting light and a role as a wall for filling the sealing member. The substrate 7 has a plurality of leads (for example, a first lead 51, a second lead 52, a third lead 53, and a fourth lead 54) on the upper surface thereof. The size of such a package 1 is appropriately set according to the number of light emitting elements to be arranged, the purpose, and the application. As the material of the substrate 7, it is preferable to use an insulating material, and it is preferable to use a material that does not easily transmit light emitted from a light emitting element or the like, external light, or the like. Further, in order to enhance the light reflectivity of the package 1, a reflective member may be provided on the light emitting element mounting surface. The reflective member is, for example, a mixture of reflective particles such as titanium oxide and an organic or inorganic binder. So-called white resist, white ink, ceramic ink, etc. fall under this category. As the binder of the organic substance, it is particularly preferable to use a silicone resin having excellent heat resistance and light resistance. As a result, light can be reflected on the surface of the substrate 7 to obtain a light emitting device having high light extraction efficiency.

In the light emitting device shown in FIGS. 2A and 2B, the first light emitting element 10 and the second light emitting element 20 are arranged alternately. As a result, the light emitted from the first light emitting element 10 and the second light emitting element 20 can be sufficiently mixed, and the color unevenness of the light emitting device in the top view can be suppressed. The arrangement of the first light emitting element 10 and the second light emitting element 20 is not limited to this. For example, the first light emitting element 10 and the second light emitting element 20 can be arranged in a row in the X direction or the Y direction, or can be arranged concentrically.

Further, the package 1 may have a form that does not have the recess 2. For example, a long substrate can be used for the package 1. Such a package 1 has flexibility, for example, can be stored in a rolled state by a reel or the like, and can be attached along a curved surface. As the material of the substrate, for example, an insulating resin such as polyimide, polyethylene terephthalate, or polyethylene naphthalate can be preferably used. The thickness of the substrate can be, for example, about 10 μm to 200 μm.

(Multiple leads)
The plurality of leads 50 have conductivity and function as electrodes for supplying power to the light emitting element. As the base material of the plurality of leads 50, for example, copper, aluminum, gold, silver, iron, nickel, or an alloy thereof, phosphor bronze, iron-containing copper, or other metals can be used. These may be a single layer or a laminated structure (for example, a clad material). In particular, it is preferable to use inexpensive copper having high heat dissipation as the base material. Further, the plurality of leads 50 may have a metal layer on the surface of the base material. The metal layer includes, for example, silver, aluminum, nickel, palladium, rhodium, gold, copper, or alloys thereof. The metal layer may be provided on the entire surface of the plurality of leads 50, or may be provided partially. Further, the metal layer can be a different layer in the region formed on the upper surface of the lead and the region formed on the lower surface of the lead. For example, the metal layer formed on the upper surface of the reed is a metal layer composed of a plurality of layers including a nickel and silver metal layer, and the metal layer formed on the lower surface of the reed is a metal layer containing no nickel metal layer. Is. Further, for example, the metal layer such as silver formed on the upper surface of the lead can be made thicker than the metal layer such as silver formed on the lower surface of the lead.

When a metal layer containing silver is formed on the outermost surface of the plurality of leads 50, it is preferable to provide a protective layer such as silicon oxide on the surface of the metal layer containing silver. As a result, it is possible to prevent the metal layer containing silver from being discolored by the sulfur component in the atmosphere. The protective layer can be formed by a vacuum process such as sputtering, but other known methods may be used.

The plurality of leads 50 include at least a first lead 51, a second lead 52, and a third lead 53. Since the plurality of leads 50 have at least three leads, the plurality of light emitting elements can be driven independently. The plurality of leads 50 may include four or more leads, and may include, for example, a fourth lead in addition to the first lead 51, the second lead 52, and the third lead 53. The fourth lead may function as a heat radiating member, or may function as an electrode in the same manner as the first lead 51 and the like.

(Resin part)
As the resin material serving as a base material, the resin portion 30 can use a thermosetting resin, a thermoplastic resin, or the like. Specifically, an epoxy resin composition, a silicone resin composition, a modified epoxy resin composition such as a silicone-modified epoxy resin, a modified silicone resin composition such as an epoxy-modified silicone resin, an unsaturated polyester resin, a saturated polyester resin, and a polyimide resin. Cured products such as compositions and modified polyimide resin compositions, resins such as polyphthalamide (PPA), polycarbonate resin, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), ABS resin, phenol resin, acrylic resin, and PBT resin. Can be used. In particular, it is preferable to use a thermosetting resin of an epoxy resin composition or a modified silicone resin composition.
Further, as the resin material of the resin portion 30, it is preferable to use a silicone resin composition (for example, SMC resin) having excellent heat resistance and light resistance.

The resin portion 30 preferably contains a light-reflecting substance in the resin material serving as the base material. As the light-reflecting substance, it is preferable to use a member that does not easily absorb light from the light emitting element and has a large difference in refractive index with respect to the resin material that is the base material. Such light-reflecting substances are, for example, titanium oxide, zinc oxide, silicon oxide, zirconium oxide, aluminum oxide, aluminum nitride and the like.

Further, the resin portion 30 may contain a filler having a low light reflectance with respect to the external light (in many cases, sunlight) of the light emitting device 100 in order to improve the contrast of the light emitting device 100. In this case, the resin portion 30 is, for example, black or a color similar thereto. As the filler, carbon such as acetylene black, activated carbon and graphite, transition metal oxides such as iron oxide, manganese dioxide, cobalt oxide and molybdenum oxide, and colored organic pigments can be used depending on the purpose.

The light emitting device of the present invention does not have to include the package 1. FIG. 3A is a schematic top view showing an example of a light emitting device, and FIG. 3B is a schematic end view of 3B-3B in FIG. 3A. The light emitting device 100 shown in FIGS. 3A and 3B does not include the package 1. The light emitting device 100 includes a first light emitting element 10 and a second light emitting element 20, a light transmitting layer 8 arranged on the side surface of each light emitting element, a resin portion 30 covering the outer surface of the light transmitting element 8, and each light emitting element. It includes a sealing member 40 located above.

The light transmitting layer 8 covers the side surface of each light emitting element, and guides the light emitted from the side surface of each light emitting element toward the upper surface of the light emitting device. That is, a part of the light that reaches the side surface of each light emitting element is reflected by the side surface and attenuated in the light emitting element, but the light transmitting layer 8 can take out the light to the outside of the light emitting element through the light transmitting layer 8. .. As the translucent layer 8, the resin material exemplified in the resin portion 30 can be used, and in particular, a thermosetting translucent resin such as a silicone resin, a silicone-modified resin, an epoxy resin, or a phenol resin is preferable. The light transmitting layer 8 preferably has a high light transmittance. Therefore, it is usually preferable that no additive that reflects, absorbs, or scatters light is added to the light transmitting layer 8.

The resin portion 30 covers the outer surface of the translucent layer 8 provided on the side surface of each light emitting element and a part of the side surface of each light emitting element. The resin portion 30 includes, for example, a difference in the coefficient of thermal expansion between the translucent layer 8 and each light emitting element (this is referred to as a “first difference in thermal expansion rate ΔT30”) and a thermal expansion between the resin part 30 and each light emitting element. When compared with the coefficient difference (this is referred to as "second coefficient of thermal expansion difference ΔT40"), the resin material to be the resin portion 30 is selected so that ΔT40 <ΔT30. As a result, it is possible to prevent the light transmitting layer 8 from peeling off from each light emitting element.

(1st light emitting element, 2nd light emitting element)
The first light emitting element 10 and the second light emitting element 20 function as a light source of the light emitting device 100, and further serve as an excitation source for the phosphor. A light emitting diode element or the like can be used for the first light emitting element 10 and the second light emitting element 20, and a nitride semiconductor (In _x Al _y Ga _1-xy N, 0 ≦ x) capable of emitting light in the visible region can be used. , 0 ≦ y, x + y ≦ 1) can be included.
Each of the first light emitting element 10 and the second light emitting element 20 has an emission peak wavelength of 430 nm to 480 nm. When the first light emitting element 10 and the second light emitting element 20 have an emission peak wavelength on the longer wavelength side than the near-ultraviolet region, there is a problem of light in the near-ultraviolet region (for example, it adversely affects the human body or an irradiated object, or emits light. It is possible to suppress the problem that the constituent members of the device are deteriorated and the luminous efficiency of the light emitting device is significantly lowered). The light emitting device 100 may include at least the first light emitting element 10 and the second light emitting element 20, and may further include another light emitting element in addition to the first light emitting element 10 and the second light emitting element 20.

(Sealing member)
The light emitting device 100 includes a sealing member 40 that covers the first light emitting element 10 and the second light emitting element 20. The sealing member 40 can protect the light emitting element and the like from external force, dust, moisture and the like. The sealing member 40 preferably transmits 60% or more of the light emitted from the light emitting element, and more preferably 90% or more. As the base material of the sealing member 40, the resin material used in the resin portion 30 can be used. As the resin material serving as the base material, a thermosetting resin, a thermoplastic resin, or the like can be used, and for example, a silicone resin, an epoxy resin, an acrylic resin, or a resin containing one or more of these can be used. The sealing member can be formed from a single layer, or can be composed of a plurality of layers. Further, light scattering particles such as titanium oxide, silicon oxide, zirconium oxide, and aluminum oxide can be dispersed in the sealing member 40.

The sealing member 40 includes a first phosphor 61 that converts the wavelength of light from the light emitting element. The first phosphor 61 may be one type of phosphor or a plurality of types of phosphors. By using a plurality of types of phosphors as the first phosphor 61, the color rendering property of the light emitting device 100 can be improved. The first phosphor 61 may be a phosphor excited by the light of the first light emitting element 10 and the second light emitting element 20, and may be, for example, (Ca, Sr, Ba) ₅ (PO ₄ ) ₃ (Cl, Br). : Eu, (Sr, Ca, Ba) ₄ Al ₁₄ O ₂₅ : Eu, (Ca, Sr, Ba) ₈ MgSi ₄ O ₁₆ (F, Cl, Br) ₂ : Eu, (Y, Lu, Gd) ₃ ( _{al, Ga) 5 O 12:} Ce, (Sr, Ca) AlSiN 3: Eu, 3.5MgO · 0.5MgF 2 · GeO 2: Mn, Ca 3 Sc 2 Si 3 O 12: Ce, CaSc 2 O 4: Ce, (La, Y) ₃ Si ₆ N ₁₁ : Ce, (Ca, Sr, Ba) ₃ Si ₆ O ₉ N ₄ : Eu, (Ca, Sr, Ba) ₃ Si ₆ O ₁₂ N ₂ : Eu, ( Ba, Sr, Ca) Si ₂ O ₂ N ₂ : Eu, (Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu, (Ca, Sr, Ba) S: Eu, (Ba, Sr, Ca) Ga ₂ A phosphor of S ₄ : Eu, K ₂ (Si, Ti, Ge) F ₆ : Mn can be used.

As the first phosphor 61, it is particularly preferable to use a phosphor having a wide half-value width, for example, (Y, Lu, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce, and further, ( It is more preferable to use a mixture of Y, Lu, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce and (Sr, Ca) AlSiN _{3: Eu.} This makes it possible to obtain a light emitting device having high color rendering properties. again,

The content of the phosphor is preferably, for example, about 9 to 60% by weight with respect to the total weight of the sealing member 40.

The sealing member 40 may be formed of an inorganic material such as a sintered body of glass or a phosphor. Thereby, the reliability of the light emitting device can be improved in the high output light emitting device.

(Protective element)
The light emitting device 100 may be provided with a protective element in order to improve the electrostatic withstand voltage. In the light emitting device 100 shown in FIG. 1A, the protective element 11 is located on the upper surface of the second lead 52. The number of protective elements may be one or a plurality. For example, the light emitting device 100 can arrange one protective element for one light emitting element. In the light emitting device 100, since the conductive path of each light emitting element is separate, the electrostatic withstand voltage of the light emitting device 100 can be further improved by arranging one protective element for each light emitting element.

(Modified example of the first embodiment)
FIG. 4A is a schematic end view of the light emitting device 100A according to one modification of the first embodiment. The light emitting device 100A is mainly different from the light emitting device 100 according to the first embodiment in that a first translucent member 15 is further provided between the convex portion 3 and the upper surface of the first light emitting element 10. Therefore, the light emitting device 100A will be described focusing on the differences from the light emitting device 100.

The light emitting device 100A includes a first translucent member 15 which is arranged on the upper surface of the first light emitting element 10 and is located below the upper surface of the sealing member 40. More specifically, the light emitting device 100A includes a first translucent member 15 between the upper surface of the convex portion 3 and the upper surface of the first light emitting element 10. In the light emitting device 100A shown in FIG. 4A, the first translucent member 15 covers the upper surface of the first light emitting element 10 and does not cover the side surface of the first light emitting element 10.

The first translucent member 15 includes, for example, a second phosphor 62. As the second phosphor 62, for example, it is preferable to use a red phosphor having a wide half-value width. By using a red phosphor as the second phosphor 62, the x value of the chromaticity of the emitted light emitted above the first light emitting element 10 becomes large, and the emitted light emitted above the first light emitting element 10 becomes large. The chromaticity of the light emitted above the second light emitting element 20 can be easily made different from the chromaticity of the emitted light. It can be easily different from the chromaticity of the emitted light emitted from the second translucent member 25. When a red phosphor is used as the second phosphor 62, the half width of the second phosphor 62 is, for example, 80 nm or more and 100 nm or less, preferably 85 nm or more and 95 nm or less. As such a second phosphor 62, for example, a red phosphor having a composition represented by the following formula (3) can be used.
(Sr, Ca) AlSiN ₃ : Eu (3)
By using a red phosphor having a composition represented by the formula (3), it is possible to improve the light extraction of the light emitting device while improving the color rendering property of the light emitting device.
The content of the second phosphor 62 is, for example, 33 to 60% by weight with respect to the total weight of the first translucent member 15.

The first translucent member 15 preferably covers only the upper surface of the first light emitting element 10. In other words, it is preferable that the first translucent member 15 covers the upper surface of the first light emitting element 10 and does not cover the side surface of the first light emitting element 10. As a result, for example, when a fluorescent material having high excitation efficiency is used as the first fluorescent material 61 in the sealing member 40. The light emitted laterally from the first light emitting element 10 can be efficiently excited. As a result, it is possible to obtain a light emitting device having good light extraction.
The first translucent member 15 is formed by various methods. For example, the first translucent member 15 may be formed by forming a resin material by printing, potting, spraying, or the like, or by attaching a sheet-shaped or block-shaped resin member with an adhesive or the like. good. Further, the translucent member containing a phosphor may be formed by, for example, an electrophoretic deposition method or the like.

FIG. 4B is a schematic end view of the light emitting device 100B according to one modification of the first embodiment. The light emitting device 100B is mainly different from the light emitting device 100 according to the first embodiment in that a second translucent member 25 is further provided between the upper surface of the sealing member 40 and the upper surface of the second light emitting element 20. Therefore, the light emitting device 100B will be described focusing on the differences from the light emitting device 100.

The light emitting device 100B includes a second translucent member 25 which is arranged on the upper surface of the second light emitting element 20 and is located below the upper surface of the sealing member 40. The second translucent member 25 does not have, for example, a phosphor. When the second translucent member 25 does not have a phosphor, most of the emitted light of the second translucent member 25 is the light of the second light emitting element 20 having a large amount of blue component. As a result, the x value of the chromaticity of the emitted light emitted above the second light emitting element 20 is relatively smaller than the x value of the chromaticity of the emitted light emitted above the first light emitting element 10. It becomes light. As a result, the chromaticity of the emitted light emitted above the first light emitting element 10 and the chromaticity of the emitted light emitted above the second light emitting element 20 can be easily made different.
Further, by providing the second translucent member 25 on the upper surface of the second light emitting element 20, the amount of the first phosphor 61 located above the second light emitting element 20 is reduced, and the second light emitting element 20 The rate of being excited by the first phosphor 61 of the light emitted upward is reduced. Therefore, for example, when the first phosphor 61 contains a yellow to red phosphor, the light emitted above the second light emitting element 20 has a chromaticity as compared with a light emitting device having no second translucent member 25. The light can have a relatively small x value. As a result, the chromaticity of the emitted light emitted above the first light emitting element 10 and the chromaticity of the emitted light emitted above the second light emitting element 20 can be easily made different.

FIG. 4C is a schematic end view of the light emitting device 100C according to one modification of the first embodiment. The light emitting device 100C is mainly different from the light emitting device 100 according to the first embodiment in that a base portion 5 is further provided below the second light emitting element 20. Therefore, the light emitting device 100C will be described focusing on the differences from the light emitting device 100.

The light emitting device 100C includes a base portion 5 below the second light emitting element 20. By providing the base portion 5 below the second light emitting element 20, the amount of the first phosphor 61 located above the second light emitting element 20 is reduced, and the first amount of light emitted above the second light emitting element 20 is reduced. The ratio of being excited by the phosphor 61 is reduced. Therefore, for example, when the first phosphor 61 contains a yellow to red phosphor, the light emitted above the second light emitting element 20 has a chromaticity as compared with a light emitting device having no second translucent member 25. The light can have a relatively small x value. As a result, the chromaticity of the emitted light emitted above the first light emitting element 10 and the chromaticity of the emitted light emitted above the second light emitting element 20 can be easily made different.

(1st translucent member, 2nd translucent member)
The first translucent member 15 is located on the upper surface of the first light emitting element 10, and the second translucent member 25 is located on the upper surface of the second light emitting element 20. The first translucent member 15 and the second translucent member 25 may be arranged in direct contact with the upper surface of the light emitting element, or may be located above the light emitting element and may be arranged with the first translucent member 15 and the like. Another member (for example, the protective layer described above) may be located between the light emitting element and the upper surface of the light emitting element.
Further, the first translucent member 15 and the second translucent member 25 can further cover the side surface of the light emitting element. Both the first translucent member 15 and the second translucent member 25 can cover the upper surface and the side surface of the light emitting element, and for example, only one translucent member can cover the upper surface and the side surface of the light emitting element. The sides can be covered.

The first translucent member 15 and the second translucent member 25 can have various shapes. In particular, the first translucent member 15 and the second translucent member 25 are preferably substantially hemispherical or substantially semi-ellipoid as shown in FIGS. 4A and 4B. In other words, it is preferable that all of the upper surfaces of the first translucent member 15 and the second translucent member 25 are curved surfaces. As a result, it is possible to prevent the light emitted from the first light emitting element 10 or the like from being reflected by the surface of the first translucent member 15 or the like and returning to the side of the first light emitting element 10 or the like.

For the first translucent member 15 and the second translucent member 25, a thermosetting resin, a thermoplastic resin, or the like can be used as the resin material as the base material. As the resin material to be the base material, a resin material that can be used as the base material of the resin portion 30 can be used. In particular, it is preferable to use a silicone resin composition or an epoxy resin composition. Further, light scattering particles such as titanium oxide, silicon oxide, zirconium oxide, and aluminum oxide can be dispersed in the first translucent member 15 and the second translucent member 25. Further, the refractive index of the resin material used as the base material of the first translucent member 15 and the resin material used as the base material of the second translucent member 25 can be different.

The first translucent member 15 and the second translucent member 25 do not have to contain a phosphor, and may also contain a second phosphor 62. The second phosphor 62 is, for example, (Ca, Sr, Ba) ₅ (PO ₄ ) ₃ (Cl, Br): Eu, (Sr, Ca, Ba) ₄ Al ₁₄ O ₂₅ : Eu, (Ca, Sr, Ba) ₈ MgSi ₄ O ₁₆ (F, Cl, Br) ₂ : Eu, (Y, Lu, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce, (Sr, Ca) AlSiN ₃ : Eu, 3.5 MgO・ 0.5MgF ₂・ GeO ₂ : Mn, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, CaSc ₂ O ₄ : Ce, (La, Y) ₃ Si ₆ N ₁₁ : Ce, (Ca, Sr, Ba) ₃ Si ₆ O ₉ N ₄ : Eu, (Ca, Sr, Ba) ₃ Si ₆ O ₁₂ N ₂ : Eu, (Ba, Sr, Ca) Si ₂ O ₂ N ₂ : Eu, (Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu, (Ca, Sr, Ba) S: Eu, (Ba, Sr, Ca) Ga ₂ S ₄ : Eu, K ₂ (Si, Ti, Ge) F ₆ : Mn phosphors are used. be able to.

The first translucent member 15 or the second translucent member 25 may be formed of an inorganic material such as a sintered body of glass or a phosphor. Thereby, the reliability of the light emitting device can be improved in the high output light emitting device.

(Base)
The base portion 5 is located below the light emitting element and has a role of reducing the volume of the sealing member 40 located above the light emitting element. In the light emitting device 100C, the base portion 5 is located below the second light emitting element 20, but is not limited to this. The base portion 5 may be located below the first light emitting element 10. Examples of the base portion 5 include ceramics such as alumina and aluminum nitride, and members containing resins such as silicone and epoxy. The base portion 5 preferably has a thermal conductivity of 150 W / m · K or more in order to appropriately dissipate heat from the light emitting element.

(Second Embodiment)
FIG. 5A is a schematic top view of the light emitting device 200 according to the second embodiment, and FIG. 5B is a schematic end view taken along line 5B-5B in FIG. 5A. In FIG. 5A, the sealing member 40 is omitted so that the inside of the recess 2 can be easily seen. The light emitting device 200 is mainly different from the light emitting device 100 according to the first embodiment in that the recessed portion 4 is provided instead of the convex portion 3. Therefore, the light emitting device 200 will be described focusing on the differences from the light emitting device 100.

The light emitting device 200 includes a first light emitting element 10 and a second light emitting element 20, and a sealing member 40 that covers the first light emitting element 10 and the second light emitting element 20 and includes a first phosphor 61. The light emitting device 200 according to the second embodiment further includes a package 1 having a recess 2, and the first light emitting element 10 and the second light emitting element 20 are arranged on the bottom surface of the recess 2.

The sealing member 40 has a recessed portion 4 that is recessed downward on a part of the upper surface. Further, the second light emitting element 20 is located in the third region 9c below the recessed portion 4. In other words, the recessed portion 4 is located above the second light emitting element 20. Further, the first light emitting element 10 is located in the fourth region 9d, which is located below the upper surface of the sealing member 40 and is located at a position different from the third region 9c. By providing the recessed portion 4 above the second light emitting element 20, the volume of the sealing member 40 located above the first light emitting element 10 is changed to the volume of the sealing member 40 located above the second light emitting element 20. Can be made larger more easily. As a result, the amount of the first phosphor 61 located above the first light emitting element 10 can be made larger than the amount of the first phosphor 61 located above the second light emitting element 20, and as a result, Of the light emitted above the sealing member 40, the chromaticity of the light emitted above the first light emitting element 10 and the chromaticity of the light emitted above the second light emitting element 20 can be easily made different.

Further, for example, when a yellow to red phosphor is used as the first phosphor 61, the x value of the chromaticity of the light emitted above the first light emitting element 10 is the color of the light emitted above the second light emitting element 20. Greater than the x value of degree. Since the light emitting device 200 according to the second embodiment has the recessed portion 4 above the second light emitting element 20, the x value of the chromaticity of the light emitted above the first light emitting element 10 is set above the second light emitting element 20. It can be made larger than the x value of the chromaticity of the light emitted from. As a result, it becomes possible to provide a light emitting device capable of emitting light having a wide range of chromaticities as a light emitting color.

The recessed portion 4 is preferably positioned so that the geometric center of the recessed portion 4 substantially coincides with the center of the second light emitting element 20 in the top view. As a result, the optical axis of the second light emitting element 20 and the optical axis of the recessed portion 4 can be aligned with each other, so that the light from the second light emitting element 20 can be efficiently taken out to the outside. Further, all of the second light emitting element 20 can be located below the recessed portion 4, and only a part of the second light emitting element 20 can be located below the recessed portion 4. The maximum width of the recessed portion 4 in top view is preferably smaller than the maximum width of the second light emitting element 20 in top view. As a result, the proportion of the return light emitted from the second light emitting element 20 returning to the second light emitting element 20 side due to the surface of the recessed portion 4 can be reduced, and the emitted light of the first light emitting element 10 is recessed. The proportion of light incident on the portion 4 can be reduced. The maximum width of the recessed portion 4 in top view is, for example, 0.5 to 0.8 times the maximum width of the second light emitting element 20 in top view. The maximum width of the recessed portion 4 in top view is, for example, 250 to 600 μm. Further, in the convex portion 3, the distance between the lowest portion and the highest portion in the height direction is, for example, 100 to 250 μm.

The recessed portion 4 can be formed at the same time when the sealing member 40 is formed by the mold, and after the first sealing member is provided in the recessed portion 2, the portion corresponding to the recessed portion 4 is formed. It can also be provided in a separate process by pressing or the like.

The characteristic portions of the light emitting devices described in the first embodiment, the modified examples of the first embodiment, and the second embodiment can be suitably applied to other embodiments. Further, in the first embodiment or the like, the x value of the chromaticity of the light emitted above the first light emitting element 10 is larger than the x value of the chromaticity of the light emitted above the second light emitting element 20. Although the embodiment of the case has been mainly described, the light emitting device of the present disclosure is not limited to this.

100 Light emitting device 100A, 100B, 100C Light emitting device 200 Light emitting device 1 Package 2 Recessed part 3 Convex part 4 Recessed part 5 Base part 6 Side wall 7 Substrate 8 Translucent layer 10 1st light emitting element 11 Protective element, 1st protective element 12 2nd Protective element 13a Protruding part 13b Recessed part 15 1st translucent member 20 2nd light emitting element 25 2nd translucent member 30 Resin part 40 Encapsulating member 50 Multiple leads 51 1st lead 52 2nd lead 53 3rd lead 54 4th lead 61 1st phosphor 62 2nd phosphor 80 Upper surface 81 Lower surface 82 1st outer surface 83 2nd outer surface 84 3rd outer surface 85 4th outer surface 9a 1st region 9b 2nd region 9c 3rd region 9d 4th area P connection

Claims (7)

The first and second light emitting elements having their respective emission peak wavelengths of 430 nm to 480 nm, and
A sealing member that covers the first light emitting element and the second light emitting element and contains the first phosphor.
A first translucent member which is arranged on the upper surface except for the side surface of the first light emitting element, is located below the upper surface of the sealing member, and contains a second phosphor.
The x value of the chromaticity of the light emitted above the first light emitting element is larger than the x value of the chromaticity of the light emitted above the second light emitting element.
The first light emitting element and the second light emitting element can be driven independently of each other.
The sealing member has a convex portion on a part of the upper surface thereof.
The convex portion and the upper surface of the first translucent member are curved surfaces.
The first light emitting element is located in the first region below the convex portion, and the first light emitting element is located.
The second light emitting element is located in a second region located below the upper surface of the sealing member and at a position different from the first region.
A light emitting device in which the highest point of the convex portion and the highest point of the first translucent member are located on a perpendicular line on the upper surface of the first light emitting element in a cross-sectional view . The light-emitting device, the second being arranged on the upper surface of the light-emitting element further comprises a second light-transmitting member positioned below the upper surface of the sealing member, the light emitting device according to claim 1. The light emitting device according to claim 1 or 2 , wherein the light emitting device further includes a base portion arranged below the second light emitting element. The light emitting device includes a package having a recess, and the light emitting device includes a package having a recess.
The light emitting device according to any one of claims 1 to 3 , wherein the first light emitting element and the second light emitting element are arranged on the bottom surface of the recess. The light emitting device according to any one of claims 1 to 4 , wherein the light emitting device emits light having a color temperature of 1800 to 7000K. The light emitting device has a first lead, a second lead, and a third lead.
The light emitting device according to any one of claims 1 to 5 , wherein the first light emitting element and the second light emitting element are arranged on the upper surface of the first lead. The light emitting device has a first lead, a second lead, a third lead, and a fourth lead.
The first light emitting element is arranged on the upper surface of the first lead.
The second light emitting element is arranged on the upper surface of the second lead.
The third lead is electrically connected to one electrode of the first light emitting element.
The light emitting device according to any one of claims 1 to 5 , wherein the fourth lead is electrically connected to one electrode of the second light emitting element.

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