JP7269792B2 - light emitting device - Google Patents

Description

The present invention relates to a light-emitting device including light-emitting elements such as light-emitting diodes.

A light-emitting device includes, for example, a substrate provided with terminals, wiring, and the like, and at least one light-emitting element mounted on the substrate. For example, Patent Literature 1 discloses a light-emitting device having a light-emitting element and a translucent member that transmits and emits light emitted from the light-emitting element to the outside.

JP 2010-272847 A

Characteristics required for a light-emitting device include, for example, high luminance, stable optical characteristics such as wavelength characteristics and light distribution characteristics, and high quality. Further, the optical characteristics required for the light-emitting device are, for example, that light of a desired wavelength (emission color) is extracted, that the wavelength of the emitted light is uniform, and that the emitted light has a desired intensity. To have a characteristic (for example, to have a desired intensity distribution within a light distribution area).

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-quality, high-luminance light-emitting device.

A light-emitting device according to the present invention comprises a substrate, a light-emitting element disposed on the substrate, and a wavelength converter disposed on the light-emitting element and configured to convert the wavelength of light emitted from the light-emitting element. a first portion having a bottom surface and curved side surfaces extending along the first portion; and a second portion having a columnar shape and a bottom surface disposed on the top surface of the first portion. Characterized by

1 is a perspective view of a light emitting device according to Example 1. FIG. 1 is a top view of a light emitting device according to Example 1. FIG. 1 is a cross-sectional view of a light emitting device according to Example 1. FIG. FIG. 10 is a cross-sectional view of a light emitting device according to Example 2; FIG. 11 is a cross-sectional view of a light emitting device according to Example 3; FIG. 11 is a cross-sectional view of a light emitting device according to Example 4; FIG. 11 is a cross-sectional view of a light emitting device according to Example 5;

Examples of the present invention will be described in detail below.

FIG. 1 is a schematic perspective view of a light emitting device 10 according to Example 1. FIG. A schematic configuration of the light emitting device 10 will be described with reference to FIG. The light emitting device 10 has a mounting substrate (first substrate, hereinafter simply referred to as substrate) 11 and a light emitting element 20 mounted on the substrate 11 . In this embodiment, the light emitting device 10 has two light emitting elements 20 arranged side by side on the substrate 11 .

The substrate 11 has, for example, an insulating base material 11A and wiring electrodes 11B formed on the base material 11A. The substrate 11 has a mounting surface on which each of the light emitting elements 20 is mounted. In this embodiment, the base material 11A has a flat plate shape and has an upper surface, which is one of its main surfaces, as the mounting surface. For example, the base material 11A is made of a material having high thermal conductivity, such as AlN. The wiring electrode 11B is made of, for example, a copper film patterned and formed on the substrate 11A.

The light emitting element 20 is, for example, a semiconductor light emitting element such as a light emitting diode. The light emitting element 20 includes, for example, a support substrate (second substrate, hereinafter simply referred to as substrate) 21 and a semiconductor light emitting layer (hereinafter simply referred to as semiconductor layer) 22 supported by the substrate 21 . For example, the substrate 21 has a flat plate shape and is made of Si. Moreover, the semiconductor layer 22 consists of a nitride semiconductor, for example.

In addition, the light emitting element 20 includes a pad electrode 23 provided on the side of the semiconductor layer 22 on the substrate 21 and a back electrode provided on the surface of the substrate 21 opposite to the semiconductor layer 22 (substrate 11 side). 24 and . For example, the semiconductor layer 22 has an n-type semiconductor layer (not shown) and a p-type semiconductor layer (not shown). For example, the pad electrode 23 is connected to the p-type semiconductor layer of the semiconductor layer 22 . Also, the back electrode 24 is connected to the n-type semiconductor layer of the semiconductor layer 22 .

Moreover, in this embodiment, the pad electrode 23 is connected to the wiring electrode 11B of the substrate 11 via a bonding wire. Also, the base material 11A of the substrate 11 has vias (not shown) penetrating between its main surfaces. The back surface electrode 24 is connected via the via to a wiring electrode (not shown) provided on the surface of the substrate 11A opposite to the wiring electrode 11B.

In this embodiment, the light emitting element 20 has a rectangular top shape. Specifically, in this embodiment, each of the substrate 21 and the semiconductor layer 22 has a rectangular top surface shape. For example, the top surface of the semiconductor layer 22 has a square shape with sides of about 1 mm. In addition, each of the light emitting elements 20 is arranged in alignment as a whole on the substrate 11 so that one side surface of each substrate 21 faces each other.

In this embodiment, the case where the light emitting device 10 has two light emitting elements 20 will be described, but the configuration of the light emitting elements 20 is not limited to this. For example, the light emitting device 10 may have only one light emitting element 20 or may have three or more light emitting elements 20 . Further, even when the light emitting device 20 has a plurality of light emitting elements 20, the arrangement configuration is not limited to the above case. Moreover, the top surface shape of the light emitting element 20 is not limited to a rectangle, and may have, for example, a polygonal shape or a circular shape.

The light-emitting device 10 has a wavelength converter 40 formed on a light-emitting element 20 and adhered to the light-emitting element 20 via an adhesive layer 30 . The adhesive layer 30 is formed, for example, in layers on the substrate 21 of the light emitting element 20 so as to bury the semiconductor layer 22 . Further, the adhesive layer 30 has translucency with respect to the light emitted from the light emitting layer 20 and the light emitted from the wavelength converter 40 . For example, the adhesive layer 30 is made of a transparent resin layer.

In this embodiment, the wavelength conversion body 40 is formed across the two light emitting elements 20 . For example, in this embodiment, the wavelength converter 40 covers the entire upper surface of the semiconductor layer 22 in each of the light emitting elements 20 and is integrally formed across the adjacent semiconductor layers 22 on the substrate 11 . The wavelength converter 40 is composed of, for example, a phosphor plate formed by sintering YAG phosphor and alumina.

The light emitting device 10 has a light reflector 50 that is formed on the substrate 11 , seals the light emitting element 20 , and partially covers the wavelength conversion body 40 . In FIG. 1, in order to illustrate the inner structure of the light reflector 50 of the light-emitting device 10, only the outer edge of the light reflector 50 is indicated by broken lines, and illustration thereof is omitted.

The light reflector 50 is reflective with respect to light emitted from the light emitting element 20 and light emitted from the wavelength converter 40 . For example, the light reflector 50 is made of a resin containing light-scattering particles (eg, titanium oxide particles).

FIG. 2 is a top view of the light emitting device 10. FIG. 3 is a cross-sectional view of the light emitting device 10, taken along line 3-3 in FIG. 2. FIG. Detailed structures of the wavelength converter 40 and the light reflector 50 in the light emitting device 10 will be described with reference to FIGS. 2 and 3. FIG.

First, the light reflector 50 is formed on the substrate 11 so as to cover the wavelength converter 40 while partially exposing the wavelength converter 40 . In this embodiment, the light reflector 50 is formed on the substrate 11 so as to expose the upper surface of the wavelength converter 40 and cover the side surface of the wavelength converter 40 .

The wavelength converter 40 faces the light emitting element 20 (semiconductor layer 22) via the adhesive layer 30, and has a surface extending along the substrate 11 as a light incident surface 40P on which light emitted from the light emitting element 20 is incident. and wavelength-converts the light incident from the light incident surface 40P. Further, the wavelength converter 40 has a surface not covered with the light reflector 50 as a light exit surface 40Q from which the light inside the wavelength converter 40 is emitted. In this embodiment, the light exit surface 40Q is the light extraction surface of the light emitting device 10. As shown in FIG.

Further, in this embodiment, the light exit surface 40Q of the wavelength converter 40 has a plane size smaller than that of the light entrance surface 40P. Moreover, the wavelength converter 40 as a whole has a tapered shape such that the distance between the side surfaces gradually decreases from the light incident surface 40P toward the light emitting surface 40Q (as the distance from the light emitting element 20 increases).

In this embodiment, the wavelength converter 40 has a side surface 41A extending vertically from the substrate 11 and a bottom surface 41B functioning as a light incident surface 40P, and has a columnar portion (third portion) 41 having a columnar shape. have

In this embodiment, the bottom surface 41B of the columnar portion 41 is entirely in contact with the adhesive layer 30 and extends along the semiconductor layer 22 (substrate 11). Further, in this embodiment, each of the bottom surface 41B of the columnar portion 41 and the top surface opposite to the bottom surface 41B has a rectangular planar shape. That is, in this embodiment, the columnar portion 41 has a square prism shape.

In addition, the wavelength converter 40 is formed integrally with the columnar portion 41 on the columnar portion 41 so that the top surface of the columnar portion 41 serves as the bottom surface, and has a curved side surface 42A tapered to a round shape portion (first ) 42 . In this embodiment, the side surface 42A extends vertically from the bottom surface and has a curved shape that is convex outward.

Also, in this embodiment, the round portion 42 has a flat upper surface. In this embodiment, the bottom and top surfaces of the round portion 42 are rectangular, and all of the side surfaces (four side surfaces in this embodiment) are curved side surfaces 42A.

Further, the wavelength converter 40 is formed integrally with the round portion 42 on the round portion 42 so that the top surface of the round portion 42 becomes the bottom surface, and has a columnar portion (second portion). 43. The columnar portion 43 has a side surface 43A extending perpendicularly to the bottom surface. In this embodiment, the columnar portion 43 has the shape of a square column having a bottom surface and a top surface smaller than the bottom surface 41B of the columnar portion 41 .

In this embodiment, the columnar portion 43 has a flat upper surface 43B. Moreover, the upper surface 43B of the columnar portion 43 is exposed from the light reflector 50 . In this embodiment, the upper surface 43B of the columnar portion 43 functions as the light exit surface 40Q of the wavelength converter 40. As shown in FIG.

In this embodiment, the wavelength converter 40 has a plate-like shape as a whole, with one principal surface as the light incident surface 40P and the other principal surface as the light exit surface 40Q. The side surface 41A of the columnar portion 41, the side surface 42A of the round portion 42, and the side surface 43A of the columnar portion 43 all constitute the side surface of the wavelength converter 40. FIG.

For example, the light incident surface 40P of the wavelength converter 40 has a rectangular shape with short sides of about 1 mm and long sides of about 2 mm. The light exit surface 40Q of the wavelength converter 40 has a rectangular shape with short sides of about 0.6-0.9 mm and long sides of about 1.2-1.8 mm. Further, the distance from the light incident surface 40P to the light emitting surface 40Q in the wavelength converter 40, that is, the thickness of the wavelength converter 40 is approximately 50 to 500 μm.

In this embodiment, the side surface 41A of the columnar portion 41, the side surface 42A of the round portion 42, and the side surface 43A of the columnar portion 43 are formed continuously and integrally. That is, the side surface of each portion is in contact with the side surface of the adjacent portion at its end.

The wavelength converter 40 can be formed, for example, by cutting a phosphor plate having principal surfaces serving as the bottom surface 41B of the columnar portion 41 and the top surface 43B of the columnar portion 43 in the following two steps.

For example, in the first step, a dicing blade (first blade) having a flat portion having the same shape as the side surface 43A of the columnar portion 43 and a curved surface portion having the same shape as the side surface 42A of the round portion 42 is used. is used to cut the phosphor plate to form grooves in the main surface of the phosphor plate. As a result, the phosphor plate is formed with the side surfaces 43A and 42A.

Next, in the second step, a blade (second blade) having a blade surface perpendicular to the main surface of the phosphor plate is used to form the grooves formed in the phosphor plate in the first step. A recess or a through hole is formed in the bottom. As a result, the phosphor plate is formed with a portion that will become the side surface 41A. For example, by grinding other main surfaces of the phosphor plate, the surface shape and surface quality of the bottom surface 41B of the columnar portion 41 and the top surface 43B of the columnar portion 43 can be stabilized.

For example, the wavelength conversion body 40 can be produced in this way. In addition, the formation method of the wavelength conversion body 40 is not limited to this. For example, the wavelength conversion body 40 can also be formed by molding.

Also, the light reflector 50 seals the light emitting element 20 (the substrate 21 , the semiconductor layer 22 , the pad electrode 23 and the back surface electrode 24 ) and each wiring electrode on the substrate 11 on the substrate 11 . This electrically protects the light emitting element 20 .

In this embodiment, the wavelength conversion body 40 is arranged on the light emitting element 20, and has a structure in which a columnar portion 41, a round portion 42, and a columnar portion 43 are stacked in order so as to share the top surface and the bottom surface of each. . As a result, the wavelength converter 40 emits high-luminance light with reduced intensity unevenness and color unevenness.

More specifically, since the wavelength converter 40 has the columnar portion 41 (third portion) closer to the substrate 11 than the round portion 42, the light emitted from the light emitting element 20 is efficiently converted into the wavelength converter. 40. Therefore, high wavelength conversion efficiency for light emitted from the light emitting element 20 can be maintained.

In addition, since the light is incident on the columnar portion 41 having a uniform thickness, unevenness in wavelength conversion within the plane of the columnar portion 41 is suppressed. Therefore, it is possible to suppress intensity unevenness and color unevenness in the plane of the columnar portion 41 in the light traveling from the columnar portion 41 toward the round-shaped portion 42 .

In addition, since the wavelength converter 40 has the round portion 42 (first portion), the light traveling from the round portion 42 toward the light exit surface 40Q can be condensed. Therefore, for example, after forming the light emitting element 20 (semiconductor layer 22) of a size that emits a sufficient amount of light, the emitted light from the light emitting element 20 can be collected in a region smaller than the light emitting region. can. As a result, for example, high-brightness light can be emitted from the light emission surface 40Q of the wavelength conversion body 40 .

Moreover, since the side surface 42</b>A of the round portion 42 , that is, the curved side portion of the wavelength conversion body 40 is provided, light can be stably condensed within the round portion 42 .

Specifically, first, the light incident on the side surface 42A of the round portion 42 is reflected toward the upper surface of the round portion 42, ie, the light exit surface 40Q, with a high probability. Also, the light incident on the side surface 42A is reflected in different directions even if the incident position is slightly different. Therefore, light reaches the entire light exit surface 40Q evenly, and light with uniform intensity and color is emitted from the light exit surface 40Q.

The wavelength conversion body 40 has the round-shaped portion 42 having such an optical effect, so that light with high and uniform brightness is emitted from the light emission surface 40Q. Further, by adjusting the shape (curvature, length, etc.) of the side surface 42, the round portion 42 can generate light having various optical characteristics (eg, luminance characteristics). Therefore, the light emitting device 10 can emit high-luminance and high-quality light.

Moreover, in the present embodiment, the wavelength conversion body 40 has a rectangular upper surface shape. As a result, it is possible to obtain light distribution characteristics having a shape that can be easily applied to various uses. For example, the light-emitting device 10 has a suitable configuration when used for lighting purposes, for example, as a vehicle lamp. For example, since the wavelength conversion body 40 has a rectangular top surface shape, it is possible to easily form light having characteristics required for a headlamp, such as high luminance in the central region and low luminance in the peripheral region. Because you can.

Note that the configuration of the wavelength converter 40 described above is merely an example. For example, in the present embodiment, the case where the wavelength conversion body 40 has the columnar portion 41, the round portion 42, and the columnar portion 43 that are integrally formed has been described. Also, the case where the shapes of the upper surface and the bottom surface of the vertically adjacent portions are the same have been described. However, the wavelength converter 40 may have, for example, a columnar portion 41, a round portion 42 and a columnar portion 43 that are separable from each other. Moreover, the top surface and the bottom surface of each vertically adjacent portion need only be optically coupled to each other, and the shapes thereof do not have to match, or they may be separated from each other.

Further, in this embodiment, the case where all the side surfaces (four side surfaces in this embodiment) of the round portion 42 are curved side surfaces 42A has been described. However, the side shape of the round portion 42 is not limited to this. The round shape part 42 should just have the part which becomes 42 A of curved-surface-shaped side surfaces in at least one part of a side surface. For example, only one of the four side surfaces of the round portion 42 may have a curved shape.

Moreover, in the present embodiment, the case where the wavelength conversion body 40 is composed of an integrally formed phosphor plate and has a wavelength conversion function as a whole has been described. However, the configuration of the wavelength converter 40 is not limited to this.

For example, the wavelength conversion body 40 may be composed of a phosphor plate forming part of the columnar section 41 and a translucent plate formed on the phosphor plate and forming another part of the wavelength conversion body 40. good. That is, the wavelength conversion body 40 may have a structure in which a plurality of members are combined, or may have a member that performs the wavelength conversion function only in part thereof.

Further, depending on the configuration of the light emitting element 20 and the application of the light emitting device 10, the entire wavelength conversion body 40 may not have the wavelength conversion function. For example, when it is used for communication or analysis using only monochromatic (single wavelength) light, it may be sufficient to extract the light emitted from the light emitting element 20 while maintaining its wavelength characteristics. In this case, the wavelength conversion body 40 does not need to have a wavelength conversion function, and may function as a simple translucent body, for example. Even in this case, since the translucent body has the structure as described above, the separation of the light reflector 50 from the translucent body can be prevented, and the light emitting device 10 with high quality and high brightness can be provided. can.

Also, in this embodiment, the case where the light reflector 50 covering the side surface of the wavelength converter 40 is formed on the substrate 11 has been described. However, the light reflector 50 may not be provided.

For example, the sides of the wavelength converting body 40 have some degree of reflective functionality even if they are optically exposed. This is because, for example, the light incident on the side surface of the wavelength conversion body 40 from inside stays inside the wavelength conversion body 40 due to, for example, total reflection. Further, by forming the wavelength conversion body 40 in a plate shape as in this embodiment, or by making the bottom surface or top surface of the wavelength conversion body 40 relatively large with respect to the side surfaces, most of the light can be emitted from the light exit surface 40Q. emit. Therefore, even if the light reflector 50 is not provided, the luminance characteristics and light distribution characteristics of the light emitted from the wavelength converter 40 can be maintained.

Thus, in this embodiment, the light-emitting device 10 includes the substrate 11, the light-emitting element 20 formed on the substrate 11, the wavelength converter 40 formed on the light-emitting element 20, and the wavelength converter 40. and a light reflector 50 covering the side surface.

In this embodiment, the wavelength converter 40 includes a columnar portion 41 having a bottom surface 41B forming a light incident surface 40P on which light emitted from the light emitting element 20 is incident, and a columnar portion formed on the columnar portion 41 and having 41 and having a curved side surface 42A; and a bottom surface formed on the round portion 42 and optically coupled to the top surface of the round portion 42. and a columnar portion 43 having the Therefore, it is possible to provide the light emitting device 10 with high quality and high brightness.

FIG. 4 is a cross-sectional view of a light emitting device 10A according to Example 2. FIG. 10 A of light-emitting devices have the same structure as the light-emitting device 10 except the structure of 40 A of wavelength conversion bodies. 40 A of wavelength conversion bodies have the same structure as the wavelength conversion body 40 except the point which consists only of the round shape part 42 and the columnar part 43. As shown in FIG.

In this embodiment, the wavelength converter 40A has a configuration corresponding to the wavelength converter 40 with the columnar portion 41 removed. In this embodiment, the bottom surface 42B of the round portion 42 is in contact with the adhesive layer 30. As shown in FIG. Further, the bottom surface 42B of the round portion 42 functions as the light incident surface 40P of the wavelength conversion body 40A. Moreover, in this embodiment, the light reflector 50 is formed on the substrate 11 so as to cover the side surface 42A of the round portion 42 and the side surface 43A of the columnar portion 43 .

As in this embodiment, the wavelength converter 40A does not have to have a columnar portion on the light emitting element 20 side. Even in this case, the brightness can be increased by the round portion 42 and the columnar portion 43 .

Thus, in this embodiment, the light-emitting device 10A includes the substrate 11, the light-emitting element 20 arranged on the substrate 11, and the light emitted from the light-emitting element 20 arranged on the light-emitting element 20. A wavelength conversion body 40A for performing wavelength conversion, which includes a round shape portion 42 (first portion) having a bottom surface disposed on the light emitting element 20 and having a curved side surface 42A, and a bottom surface on the top surface of the round shape portion 42. is arranged and has a columnar portion (second portion) 43 having a columnar shape, and a wavelength converter 40A having a columnar shape. Therefore, it is possible to provide the light emitting device 10A with high quality and high brightness.

FIG. 5 is a cross-sectional view of a light emitting device 10B according to Example 3. FIG. The light emitting device 10B has the same configuration as the light emitting device 10A except for the configuration of the wavelength conversion body 40B. In this embodiment, the wavelength converter 40B has a curved side surface 44A recessed on the opposite side of the round portion 42 between the round portion 42 and the columnar portion 43 (the third portion). ) 44.

In other words, in this embodiment, the wavelength conversion body 40B has a side surface formed so that the boundary between the round portion 42 and the columnar portion 43 is continuously bent. Therefore, in this embodiment, there is no clear point of inflection between the round portion 42 and the columnar portion 43 .

The wavelength conversion body 40B may have a configuration in which the round-shaped portion 42 and the columnar portion 43 are connected by such a wave-shaped portion, for example. Even in this case, if the portion to be the round-shaped portion 42 and the portion to be the columnar portion 43 are sufficiently present, high luminance can be achieved.

In this case, it is not necessary to form a clear inflection point between the round portion 42 and the columnar portion 43 when forming the wavelength conversion body 40B. Therefore, the restrictions on the side shape are relaxed, and the yield can be improved.

Thus, in the present embodiment, the wavelength converter 40B connects the side surface 42A of the round portion 42 and the side surface 43A of the columnar portion 43 between the round portion 42 and the columnar portion 43 in a curved shape. It has a connecting portion (a third portion, eg, a round portion 44) having a side surface 44A. This makes it possible to provide the light emitting device 10B with high quality and high brightness.

FIG. 6 is a cross-sectional view of a light emitting device 10C according to Example 4. FIG. The light emitting device 10C has the same configuration as the light emitting device 10 except for the configuration of the wavelength conversion body 40C. In this embodiment, the wavelength conversion body 40C has the same configuration as the wavelength conversion body 40 except for the configuration of the round portion 45 and the columnar portion 46. As shown in FIG.

In this embodiment, the wavelength conversion body 40C is formed on the columnar portion 41, and has a round portion 45 having side surfaces 45A and 45B that are curved and have different curvatures so as to face opposite sides. have. Further, the wavelength converter 40</b>C has a columnar portion 46 having a bottom surface arranged on the upper surface of the round portion 45 and having a columnar shape.

Of the side surfaces 45A and 45B of the round portion 45, the columnar portion 46 is formed on the side surface 45A having a small curvature and extending vertically from the bottom surface, and the side surface 46A formed on the side surface 45B having a large curvature and extending vertically from the bottom surface. and an extending side surface 46B. In addition, the columnar portion 46 has an upper surface 46C forming the light exit surface 40Q of the wavelength converter 40C.

In this embodiment, the columnar portion 46 is provided on the round portion 45 at a position eccentric (biased) from the columnar portion 41 and the round portion 45 . By arranging the columnar portion 46 in this way, it is possible to provide a luminance gradient to the light emitted from the light emitting surface 40Q.

Specifically, the side surface 46A of the columnar portion 46 is positioned closer to the end of the light incident surface 40P than the side surface 46B when viewed from the direction perpendicular to the light exit surface 40Q. As a result, the area near the side surface 46A has a lower luminance than the area near the side surface 46B. Therefore, from the light exit surface 40Q, light having a characteristic that the luminance gradually increases from the side surface 46A toward the side surface 46B is emitted.

In this embodiment, the case where the side surfaces 45A and 45B of the round portion 45 have different curvatures has been described. However, the configuration of the round portion 45 is not limited to this. For example, the rounded portions 45 may have sides of the same curvature.

That is, the wavelength conversion body 40C includes the round shape portion 42 in the wavelength conversion body 40, a columnar portion 46 provided on the round shape portion 42 at a position eccentric from the top surface of the round shape portion 42 or on a part of the top surface, It may be composed of Even in this case, the wavelength converter 40C can be configured to emit light having a luminance gradient.

Thus, in this embodiment, the columnar portion 46 of the wavelength converter 40</b>C is formed on the round portion 45 at a position offset from the upper surface of the round portion 45 . Therefore, it is possible to provide the light emitting device 10C having the wavelength converter 40C that has a luminance gradient and emits high luminance light.

FIG. 7 is a cross-sectional view of a light emitting device 10D according to Example 5. FIG. The light emitting device 10D has the same configuration as the light emitting device 10 except for the configuration of the wavelength conversion body 40D. Also, the wavelength converter 40</b>D has the same configuration as the wavelength converter 40 except for the configurations of the round portion 47 and the columnar portion 48 .

In this embodiment, the round-shaped portion 47 of the wavelength conversion body 40D is arranged on a side surface (first side surface) 47A extending vertically from the bottom surface and having a concave curved surface shape, and on the side opposite to the side surface 47A. and a side surface (second side surface) 47B extending perpendicularly from and having an outwardly convex curved surface shape.

In this embodiment, the columnar portion 48 has a side surface 48A that extends perpendicularly to the bottom surface from the end of the side surface 47A of the round portion 47, and a side surface 48A that extends vertically from the end of the side surface 47B of the round portion 47 to the bottom surface. and a vertically extending side surface 48B. In addition, the columnar portion 48 has an upper surface 48C forming the light exit surface 40Q.

Thus, in this embodiment, by forming the round portion 47, it is possible to increase the luminance gradient within the light exit surface 40Q. More specifically, when viewed from the direction perpendicular to the light exit surface 40Q, the areas near the side surfaces 47A and 48A are areas that do not overlap the light entrance surface 40P. Therefore, the light incident from the light incident surface 40P is difficult to reach the regions near the side surfaces 47A and 48A, or is reflected several times in the wavelength converter 40, and travels a relatively long optical path. reach. Therefore, the areas near the side surfaces 47A and 48A have relatively low brightness within the light exit surface 40Q.

Further, a region near the side surface 48A of the columnar portion 48 is provided so as to bite into the light reflector 50. As shown in FIG. Therefore, the light reflector 50 exists under the region near the side surface 48A of the columnar portion 48. As shown in FIG.

As a result, the region in the vicinity of the side surface 48A of the columnar portion 48 becomes a region with lower heat radiation performance than other regions within the wavelength converter 40D. Therefore, when the light-emitting element 20 is driven, the region near the side surface 48A of the columnar portion 48 becomes a region where the temperature is higher than other regions (region where heat is less likely to escape). Therefore, the wavelength conversion efficiency of the wavelength converter 40D in the region near the side surface 48A of the columnar portion 48 becomes lower. As a result, the area near the side surface 48A of the columnar portion 48 becomes an area with relatively low luminance within the light exit surface 40Q.

On the other hand, the area near the side surface 48B of the columnar portion 48 is an area that overlaps the light incident surface 40P when viewed from the direction perpendicular to the light emitting surface 40Q. Therefore, most of the light incident from the light incident surface 40P reaches the area near the side surface 48B of the columnar portion 48. As shown in FIG. Also, by adjusting the position of the side surface 48B, the side surface 48B can be arranged above the central region of the light incident surface 40P. As a result, the region near the side surface 48B of the columnar portion 48 has the highest brightness within the light incident surface 40Q.

Further, a round portion 47, which is another portion of the wavelength converter 40D, is provided below the area near the side surface 48B of the columnar portion 48. As shown in FIG. Therefore, the heat generated in the region near the side surface 48B of the columnar portion 48 easily propagates through the wavelength converter 40D. Therefore, the area near the side surface 48B of the columnar portion 48 has higher heat radiation performance than other areas, and has higher wavelength conversion efficiency than other areas. As a result, the area near the side surface 48B of the columnar portion 48 has a higher luminance than the other areas.

Thus, in this embodiment, the round portion 47 of the wavelength conversion body 40D has a curved side surface 47A that curves outward and a curved side surface 47B that curves inward with respect to the bottom surface. Therefore, the wavelength converter 40D is such that light with a large luminance gradient (luminance change) is emitted from the light exit surface 40Q.

Also in this embodiment, by configuring the wavelength converter 40D so that the light incident surface 40Q is smaller than the light incident surface 40P, the light incident from the light incident surface 40P is collected and emitted. It can be emitted from the surface 40Q. Therefore, it is possible to provide the light emitting device 10D having the wavelength converter 40D that has a large luminance gradient and emits high luminance light.

Considering that the light emitting surface 40Q of the wavelength converter 40D is provided with a luminance gradient, the wavelength converter 40D need not have the shape described above. For example, the light exit surface 40Q of the wavelength converter 40D may have a region extending outside the light entrance surface 40P when viewed from the direction perpendicular to the light exit surface 40Q. As a result, the area of the light exit surface 40Q shifted to the outside of the light entrance surface 40P becomes an area with low luminance, and a luminance gradient can be provided as a whole.

In other words, for example, the top surface 48C of the columnar portion 48 in the wavelength conversion body 40D is the light incident surface 40P on which the light emitted from the light emitting element 20 in the wavelength conversion body 40D is incident when viewed from the direction perpendicular to the top surface 48C. It is only necessary to have a region extending outside of the . Therefore, it is possible to provide a light emitting device 10D with high luminance, having the wavelength converter 40D that emits light having a difference in luminance from the light exit surface 40Q.

10, 10A to 10D Light emitting device 20 Light emitting element 40, 40A to 40D Wavelength converter

Claims (8)

a substrate;
a light emitting element disposed on the substrate;
A wavelength converter arranged on the light emitting element via an adhesive layer to convert the wavelength of light emitted from the light emitting element, the wavelength converting body having a bottom surface extending along the substrate and a curved side surface. and a second portion having a bottom surface disposed on the top surface of the first portion and having a columnar shape,
A light-emitting device, wherein the wavelength converter is a phosphor plate in which the first portion and the second portion are integrally formed . 2. The light-emitting device according to claim 1, wherein the side surfaces of the first portion arranged opposite to each other extend perpendicularly from the bottom surface and have a curved shape that protrudes outward. The first portion has a first side surface extending vertically from the bottom surface and having a concave curved shape, and a first side surface opposite to the first side surface, extending vertically from the bottom surface and projecting outward. 3. The light-emitting device according to claim 1, further comprising a second side surface having a curved surface shape. 4. The apparatus according to any one of claims 1 to 3, wherein the center of the top surface of the second portion is provided at a position eccentric with respect to the center of the bottom surface of the first portion. Luminescent device. The upper surface of the second portion extends outside a light incident surface on which light emitted from the light emitting element in the wavelength conversion body is incident when viewed from a direction perpendicular to the upper surface of the second portion. 5. A light-emitting device according to claim 3 or 4, characterized in that it has a region in which the 6. The light emission according to any one of claims 1 to 5, wherein the wavelength conversion body has a third portion provided closer to the light emitting element than the first portion and having a columnar shape. Device. 7. The method according to any one of claims 1 to 6, further comprising a light reflector covering a side surface of said wavelength converter and having reflectivity with respect to light generated by said light emitting element and said wavelength converter. A light emitting device as described. The wavelength converter is characterized by having a third portion having a curved side surface recessed on the side opposite to the first portion between the first portion and the second portion. 8. A light emitting device according to any one of claims 1 to 7.

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