Light-emitting device

Abstract

This light-emitting device has: a substrate; a light-emitting part that is provided on the substrate, includes a semiconductor light-emitting element that includes a light-emitting layer, and has an upper surface from which emission light from the light-emitting layer is emitted; an optical function part that comprises a light-transmitting member and has a base part that continuously extends so as to cover the upper surface of the light-emitting part and a plurality of protrusions that are formed on the base part; a spacer part that separates the upper surface of the light-emitting part and a lower surface of the base part, which are opposite each other, at prescribed spacing, thereby forming a gap between the upper surface of the light-emitting part and the lower surface of the base part; a light-reflecting part that comprises a light-reflecting material and covers at least a portion of a side surface of the light-emitting part, a side surface of the spacer part, or a side surface of the base part; and a low-refractive-index part that is provided in the gap and is formed from a low-refractive-index substance that has a lower refractive index than the optical function part.

Description

Light-emitting device

[0001] The present invention relates to a light emitting device including a light emitting element and a method for manufacturing the same.

[0002] 2. Description of the Related Art Light-emitting devices that use light-emitting elements such as light-emitting diodes (LEDs) as light sources have been known.

[0003] For example, Patent Document 1 discloses a light-emitting module having a semiconductor light-emitting element, an optical wavelength conversion element and a transparent element stacked on the semiconductor light-emitting element, and having a plurality of protrusions on the transparent element.

[0004] JP 2010-219163 A

[0005] For example, in a light-emitting module such as that disclosed in Patent Document 1, when light incident from the underside of a transparent member is emitted upward, it spreads in a direction perpendicular to the light-emitting module, i.e., in a lateral direction relative to the optical axis direction, and the light is emitted at a wide angle relative to the optical axis direction. Therefore, in devices that require a narrow-angle component, it is difficult to apply a light-emitting module that emits light at such a wide angle.

[0006] The present invention has been made in view of the above-mentioned points, and has an object to provide a light emitting device that can achieve a narrow angle of light emitted from the light emitting device.

[0007] The light emitting device according to the present invention is characterized by comprising: a substrate; a light emitting portion arranged on the substrate, the light emitting portion including a semiconductor light emitting element including a light emitting layer, and having an upper surface from which light emitted from the light emitting layer is emitted; an optical function portion made of a light-transmitting material and having a base portion extending continuously to cover the upper surface of the light emitting portion and a plurality of convex portions formed on the base; a spacer portion separating the upper surface of the light emitting portion and the lower surface of the base, which are opposed to each other, by a predetermined distance to form a gap between the upper surface of the light emitting portion and the lower surface of the base; a light reflecting portion made of a light-reflective material and covering at least a portion of the side surface of the light emitting portion, the side surface of the spacer portion, or the side surface of the base; and a low refractive index portion arranged in the gap and formed of a low refractive index material having a refractive index lower than that of the optical function portion.

[0008] FIG. 1 is a top view of a light emitting device according to Example 1 of the present invention. FIG. 2 is a cross-sectional view of a light emitting device according to Example 1 of the present invention. FIG. 3 is a diagram showing an optical path of a light emitting device according to a comparative example. FIG. 4 is a diagram showing an optical path of a light emitting device according to Example 1 of the present invention. FIG. 5 is a diagram showing the directional characteristics of emitted light from a light emitting device according to Example 1 of the present invention. FIG. 6 is a diagram showing a luminous flux ratio within a narrow angle depending on the thickness of a low refractive index portion of a light emitting device according to Example 1 of the present invention. FIG. 7 is a diagram showing a luminous flux ratio within a narrow angle depending on the thickness of a base portion of an optically functional portion of a light emitting device according to Example 1 of the present invention. FIG. 8 is a diagram showing a luminous flux ratio within a narrow angle depending on the radius of convex portions of a light emitting device according to Example 1 of the present invention. FIG. 9 is a diagram showing an example of the number of convex portions arranged in a light emitting device according to Example 1 of the present invention. FIG. 10 is a diagram showing a luminous flux ratio within a narrow angle depending on the number of convex portions arranged in a light emitting device according to Example 1 of the present invention. FIG. 11 is a diagram showing an example of an arrangement of first convex portions and second convex portions of a light emitting device according to Example 1 of the present invention. FIG. 12 is a diagram showing a luminous flux ratio within a narrow angle depending on the radius of a second convex portion of a light emitting device according to Example 1 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 5 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 6 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 7 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 8 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 9 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 10 of the present invention. FIG. 1 is a top view of a light-emitting device according to Modification 11 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 11 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 12 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 13 of the present invention. FIG. 1 is a top view of a light-emitting device according to Modification 14 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 14 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 15 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 16 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 17 of the present invention. FIG. 1 is a top view of a light-emitting device according to Modification 18 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 18 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to Modification 19 of the present invention. FIG. 1 is a cross-sectional view of a light-emitting device according to1 is a cross-sectional view of a light emitting device according to Modification 21 of the present invention. 2 is a cross-sectional view of a light emitting device according to Modification 22 of the present invention. 3 is a cross-sectional view of a light emitting device according to Modification 22 of the present invention. 4 is a diagram showing the ratio of luminous flux within a narrow angle depending on the number of arranged convex portions and the thickness of the low refractive index portion of the light emitting device according to Example 1 of the present invention. 5 is a top view of a light emitting device according to Example 2 of the present invention. 6 is a cross-sectional view of a light emitting device according to Example 2 of the present invention. 7 is a diagram showing a schematic view of the aperture angle of the second portion of the convex portions in the light emitting device according to Example 2 of the present invention. 8 is a diagram showing the ratio of luminous flux within a narrow angle depending on the aperture angle of the second portion of the convex portions of the light emitting device according to Example 2 of the present invention. 9 is a diagram showing the ratio of luminous flux within a narrow angle depending on the thickness of the base of the optical function portion of the light emitting device according to Example 2 of the present invention. 10 is a diagram showing an optical path of the light emitting device according to Example 1 of the present invention. 11 is a diagram showing an optical path of the light emitting device according to Example 2 of the present invention.

[0009] A first embodiment of the present invention will be described in detail below. In the following description and accompanying drawings, the same reference numerals are used to designate substantially the same or equivalent parts.

[0010] The configuration of a light emitting device 1 according to Example 1 will be described with reference to Figures 1 and 2. Figure 1 is a top view of the light emitting device 1 according to Example 1. Figure 2 is a cross-sectional view of the light emitting device 1 shown in Figure 1 taken along line AA.

[0011] (Light-emitting device) The light-emitting device 1 includes a substrate 10, a light-emitting section 20 consisting of a semiconductor light-emitting element 21 arranged on the substrate 10 and a wavelength conversion member 22 arranged on the upper surface of the semiconductor light-emitting element 21, an optical function section 30 arranged above the light-emitting section 20, a low refractive index section 40 arranged between the upper surface of the light-emitting section 20 and the lower surface of the optical function section 30, and a light-reflecting member 50 covering the side surface of the light-emitting section 20.

[0012] (Substrate) The substrate 10 is an insulating substrate made of ceramic such as aluminum nitride (AlN) and has a rectangular upper surface. The substrate 10 has a recessed portion on the upper surface, which has a rectangular bottom surface and is open upward, in a central region of the upper surface.

[0013] The substrate 10 may be integrally formed to have a recessed portion that opens upward, or may be formed by joining a flat plate and a frame body that has a frame shape that follows the outer edge of the flat plate. The substrate 10 may also be made of an insulating material other than ceramic, such as a resin material.

[0014] The substrate 10 also has a pair of wiring electrodes (not shown) made of metal on the bottom surface of the recess, which can supply power to the semiconductor light emitting element 21 from outside the substrate 10. For example, the wiring electrodes are formed so as to be electrically connected to the outside of the substrate 10 via a through electrode or the like (not shown).

[0015] (Light Emitting Element) The semiconductor light emitting element 21 is a light emitting diode (LED) having a rectangular upper surface and a gallium nitride (GaN)-based semiconductor structure layer including a light emitting layer that emits blue light. As shown in FIG. 2 , the semiconductor light emitting element 21 is disposed on the bottom surface of the recess of the substrate 10 so that its side surface is spaced apart from the inner surface of the recess of the substrate 10.

[0016] The semiconductor light emitting element 21 is a flip-chip LED element that includes a semiconductor structure layer (not shown) and a pair of element electrodes (not shown) on the underside of a light-transmitting growth substrate (not shown) and is configured to emit light from the upper surface of the growth substrate. In other words, the upper surface of the semiconductor light emitting element 21 is a light emitting surface that emits light.

[0017] The pair of element electrodes of the semiconductor light emitting element 21 are electrically connected to a pair of wiring electrodes formed on the bottom surface of the recess of the substrate 10. That is, the semiconductor light emitting element 21 is mounted on the substrate 10 in a flip-chip manner, and is configured to be electrically conductive so that power can be supplied from an external source via the wiring electrodes formed on the substrate 10.

[0018] A light-reflecting layer may be formed on the lower surface of the semiconductor structure layer of the semiconductor light-emitting element 21, particularly between the semiconductor structure layer and the pair of element electrodes. This light-reflecting layer may reflect light emitted downward on the side opposite the growth substrate and direct it toward the upper surface, which is the light-emitting surface of the semiconductor light-emitting element 21, thereby improving the light extraction efficiency from the upper surface, which is the light-emitting surface, of the growth substrate.

[0019] In the first embodiment, the semiconductor light emitting element 21 is a light emitting element having a chip size of, for example, a square with a side length D1 of about 1.0 mm on each side of the top surface. In this case, the light emitting surface of the semiconductor light emitting element 21 is a square with a side length D1 of about 1.0 mm on each side.

[0020] The semiconductor light emitting element 21 is not limited to the above structure, and may be a flip-chip type semiconductor light emitting element of other chip sizes. The top surface of the semiconductor light emitting element may have a rectangular shape, such as a rectangle.

[0021] LED elements of other connection configurations may also be used for the semiconductor light-emitting element 21. The semiconductor light-emitting element 21 may be, for example, a wire-bonded light-emitting element that includes a support substrate, a semiconductor structure layer on the upper surface of the support substrate, and electrode pads that can be wire-bonded on the semiconductor structure layer, with a pair of wirings and the electrode pads electrically connected by conductive metal wires such as gold (Au).

[0022] Furthermore, the light emitting element may be one in which a semiconductor structure layer provided on the upper surface of a support substrate and a pair of electrode pads formed on the upper surface of the support substrate are electrically connected by metal wiring routed between the semiconductor structure layer and the support substrate, or one in which current can be applied to the semiconductor structure layer between an electrode formed on the lower surface of a conductive support substrate and an electrode formed on the support substrate. In this case, the length of one side of the upper surface of the semiconductor structure layer formed on the upper surface of the support substrate may be designed as D1.

[0023] In the first embodiment, the semiconductor light emitting element 21 may be an element that emits light from the surface opposite to the surface facing the bottom surface of the recess of the substrate 10, that is, from the top surface.

[0024] Although the first embodiment has been described above with reference to the semiconductor light emitting element 21 having a square upper surface (light emitting surface) shape, the light emitting surface of the semiconductor light emitting element 21 may have a rectangular shape. For example, if the light emitting surface of the semiconductor light emitting element 21 is rectangular, the shape of the light emitting surface can be 0.1% to 20% of the long side and 0.1% to 20% of the short side.

[0025] (Wavelength Conversion Member) The wavelength conversion member 22 is disposed on the upper surface of the semiconductor light emitting element 21 via a light-transmitting adhesive (not shown).

[0026] 2, the wavelength conversion member 22 is formed so that its bottom surface covers the light emission surface of the semiconductor light emitting element 21, i.e., the upper surface of the semiconductor light emitting element 21. Therefore, the bottom surface of the wavelength conversion member 22 is a light incident surface of the wavelength conversion member 22 through which light emitted from the semiconductor light emitting element 21 enters.

[0027] Furthermore, light incident from the light incident surface, which is the bottom surface of wavelength conversion member 22, is guided from the bottom surface to top surface 22S and exits from the top surface. Here, light incident from the light incident surface, which is the bottom surface of wavelength conversion member 22, and traveling toward the side surface of wavelength conversion member 22 is reflected by light reflecting member 50, which will be described later, toward the wavelength conversion member 22 and exits from top surface 22S of wavelength conversion member 22. In other words, top surface 22S of wavelength conversion member 22 is the light exit surface of wavelength conversion member 22, i.e., the light exit surface of light-emitting unit 20.

[0028] The wavelength conversion member 22 can be configured to be slightly larger than the upper surface of the semiconductor light emitting element 21. The light-transmitting adhesive between the semiconductor light emitting element 21 and the wavelength conversion member 22 preferably reaches the side surface of the semiconductor light emitting element 21 and is formed to cover the side surface of the semiconductor light emitting element 21 in a fillet-like shape. In this case, the light reflecting member 50 covers the fillet-like adhesive side surface, thereby enabling light emitted from the side surface of the semiconductor light emitting element 21 to be efficiently guided to and incident on the wavelength conversion member 22. In other words, the light reflecting member 50 is configured to cover the side surface of the semiconductor light emitting element via the fillet-like adhesive side surface.

[0029] The wavelength conversion member 22 is made of, for example, alumina (Al) containing yttrium aluminum garnet (YAG:Ce) phosphor particles using cerium (Ce) as an activator. ２ O ３ The wavelength conversion member 22 converts a part of the blue light from the semiconductor light emitting element 21 that is incident on the bottom surface, which is the light incident surface, into yellow light, and emits white light from the top surface 22S, which is the light exit surface.

[0030] In this Example 1, the bottom surface of the wavelength conversion member 22 is formed to have a shape that is approximately the same as the top surface of the semiconductor light emitting element 21. That is, when the semiconductor light emitting element 21 is a chip having an upper surface shape of a square with a side length D1 of approximately 1.0 mm as exemplified above, the bottom surface of the wavelength conversion member 22 also has a square shape with a side length of the same length as the side length D1 of the semiconductor light emitting element 21 as exemplified above.

[0031] Regarding the shape, the size is such that an error of about 0.1 mm on each side is allowed, and each side may be in the range of 0.9 mm to 1.1 mm, and may also be 0.8 mm to 1.2 mm depending on the element shape, etc.

[0032] Furthermore, the shape of the bottom surface of the wavelength conversion member 22 is formed in accordance with the type of the semiconductor light emitting element 21 and in correspondence with the light emitting region on the upper surface of the semiconductor light emitting element 21. In the first embodiment, the upper surface of the semiconductor light emitting element 21 forms the light emitting surface of the semiconductor light emitting element 21, and the upper surface of the semiconductor light emitting element 21 is the light emitting region, but depending on the configuration of the semiconductor light emitting element 21, there are cases where the entire upper surface of the semiconductor light emitting element 21 is not the light emitting region.

[0033] For example, in the case where the light emitting region and the electrode pad for wire bonding are formed separately for the semiconductor light emitting element 21 having an electrode to which power is supplied by wire bonding, the wavelength conversion member 22 is formed in a shape that covers only the light emitting region and does not cover the electrode pad for wire bonding. In other words, the shape of the bottom surface of the wavelength conversion member 22 is a shape that substantially matches the shape of the light emitting region on the upper surface of the semiconductor light emitting element 21.

[0034] 2, the wavelength conversion member 22 has inwardly inclined side surfaces and is formed to taper upward from the bottom surface. That is, the wavelength conversion member 22 has a rectangular prism-shaped lower portion extending vertically from the bottom surface, a rectangular truncated pyramid-shaped middle portion with inclined side surfaces formed on the lower portion, and a rectangular prism-shaped upper portion formed on the middle portion. In other words, the wavelength conversion member 22 has a shape in which a rectangular prism shape, a rectangular truncated pyramid shape, and a rectangular prism shape are integrally formed from the bottom surface upward. The side surfaces of the lower portion and the middle portion, and the side surfaces of the middle portion and the upper portion are formed continuously.

[0035] By forming the central portion of wavelength conversion member 22 in a quadrangular pyramid shape, light incident on the light incident surface of wavelength conversion member 22 can be reflected by the inclined surface of the central portion and concentrated on upper surface 22S, which is the light exit surface of wavelength conversion member 22. This makes it possible to increase the brightness of light exiting upper surface 22S of wavelength conversion member 22.

[0036] In this Example 1, the shape of the upper surface 22S of the wavelength conversion member 22 was a square similar to the shape of the bottom surface. In addition, in this Example 1, the length D2 of one side of the upper surface 22S of the wavelength conversion member 22 was set to approximately 0.85 mm.

[0037] The upper surface 22S of the wavelength conversion member 22 is not limited to the above dimensions and may have other dimensions. The upper surface 22S of the wavelength conversion member 22 may have a rectangular shape, such as a rectangle.

[0038] Furthermore, in the first embodiment, for example, a coating layer RE having light transmissivity and low affinity with the resin material constituting the light reflecting member 50 (described later) is formed on the surface of the upper surface 22S of the wavelength conversion member 22. The coating layer RE can be made of, for example, a fluororesin having the property of repelling uncured resin. This can prevent the resin material, such as the adhesive that bonds the light reflecting member 50 (described later) or the optical function unit 30, from creeping up onto the upper surface 22S of the wavelength conversion member 22. The coating layer RE can be formed to a thickness of, for example, 1 nm or more and 1 μm or less and can be configured to leave the irregularities formed on the upper surface 22S of the wavelength conversion member 22 on the surface. Therefore, even when the coating layer RE is provided, the luminous efficiency can be maintained.

[0039] (Optical function part) The optical function part 30 is disposed on the upper surface 22S of the wavelength conversion member 22, and is a member in which a flat base 31, a plurality of convex parts 32 formed on the upper surface of the base 31, and a spacer part 33 formed on the lower surface of the base 31 are integrally formed. The optical function part 30 is, for example, a lens array made of silicone resin having a refractive index n = 1.41.

[0040] The light emitted from the upper surface 22S of the wavelength conversion member 22 is incident on the lower surface of the base 31 via the low refractive index portion 40 described below, propagates inside the optical function portion 30, and is emitted to the outside of the light emitting device 1 from the surfaces of the convex portions 32. In other words, the lower surface of the base 31 of the optical function portion 30 functions as a light incident surface of the optical function portion 30, and each surface of the convex portions 32 functions as a light exit surface of the optical function portion 30.

[0041] The base 31 is a flat plate-like portion that covers the upper surface 22S of the wavelength conversion member 22. In this Example 1, the shape of the upper surface of the base 31 is a shape that generally matches the upper surface of the semiconductor light emitting element 21 and the bottom surface of the wavelength conversion member 22. In other words, in this Example 1, the upper surface of the semiconductor light emitting element 21, the bottom surface of the wavelength conversion member 22, and the outer shape of the base 31 are each generally equal to the length D1 of one side of the upper surface of the semiconductor light emitting element 21. As for the shape of the base 31 that generally matches the upper surface of the semiconductor light emitting element 21 and the bottom surface of the wavelength conversion member 22, an error of about 0.1 mm on each side is allowed, and each side may be in the range of 0.9 mm to 1.1 mm, or may be 0.8 mm to 1.2 mm depending on the element form, etc.

[0042] In the first embodiment, the thickness T1 of the base portion 31 is set to about 50 μm.

[0043] The convex portions 32 are hemispherical lenses formed to protrude upward on the upper surface of the base 31. As shown in Fig. 1 , the convex portions 32 are arranged on the upper surface of the base 31 symmetrically with respect to the center point of the upper surface of the base 31.

[0044] In this Example 1, a total of nine convex portions 32 are arranged in a matrix of three rows and three columns on the top surface of the base 31 of the optical function unit 30. Furthermore, when the top surface of the base 31 of the optical function unit 30 is divided into nine sections at equal intervals in the X and Y directions, the nine convex portions 32 are arranged such that the center point P1 of each section becomes the center point of each convex portion 32. Each convex portion 32 is formed in a hemispherical shape with a radius R1 centered around the center point P1 in each section. Furthermore, the radius R1 of each convex portion 32 is formed to be 16.5% of the length of one side of the top surface of the base 31 (corresponding to the length D1 of one side of the top surface of the semiconductor light emitting element 21 in this Example 1).

[0045] In the first embodiment, the light-emitting surface, which is the upper surface of the light-emitting unit 20, is located directly below each of the convex portions 32. That is, the upper surface of the wavelength conversion member 22 and the upper surface of the coating layer RE are located directly below each of the convex portions 32. In particular, the upper surface of the light-emitting unit 20 (in other words, the upper surface of the wavelength conversion member 22 or the upper surface of the coating layer RE) is located directly below all of the convex portions 32 located at the outermost periphery. This allows the shape of the light source image projected from the light-emitting device 1 to be closer to the shape of the upper surface of the light-emitting unit 20 than when the light-emitting unit 20 is not located directly below the outermost convex portion, thereby improving the ease of design in applications where the shape of the light source image is designed. For example, the light source image can be made approximately square for the square upper surface shape of the light-emitting unit 20 in the first embodiment.

[0046] In this Example 1, when viewed from above, the outer edge of the upper surface of the light-emitting unit 20 (i.e., the outer edge of the upper surface of the wavelength conversion member 22) is located directly below the convex portions 32 arranged on the outermost periphery. In other words, in this Example 1, when viewed from above, the outer edge end of the optical function unit 30 is located outside the outer edge of the upper surface of the light-emitting unit 20 (i.e., the outer edge of the upper surface of the wavelength conversion member 22) when viewed from above. In this case, it is preferable that the outer edge of the upper surface of the light-emitting unit 20 (i.e., the outer edge of the upper surface of the wavelength conversion member 22) is located outside the tops of the convex portions 32 arranged on the outermost periphery.

[0047] The spacer portion 33 is a spacer that separates the upper surface 22S of the wavelength conversion member 22 and the bottom surface of the base portion 31 by a predetermined distance.

[0048] In this Example 1, the spacer portion 33 is a protruding portion that protrudes downward along the outer edge of the lower surface of the base portion 31. Also, in this Example 1, the spacer portion 33 is formed to a height that forms a gap or space with a thickness T2 of 50 μm between the upper surface 22S of the wavelength conversion member 22 and the lower surface of the base portion 31.

[0049] In this Example 1, the width of the spacer portion 33 is 50 μm. That is, the length between the inner walls of the spacer portion 33 on the opposing sides of the base portion 31 in the cross section of FIG. 2 is about 0.9 mm.

[0050] In addition, in the optical function unit 30, the lower surface of the spacer unit 33 and the upper surface of the light reflecting member 50 are bonded together via a translucent adhesive (not shown) in the region of the upper surface of the light reflecting member 50 described below. Note that the lower surface of the spacer unit 33 and the upper surface of the light reflecting member 50 may be bonded together by the resin component of the light reflecting member 50 without using an adhesive.

[0051] (Low Refractive Index Portion) The low refractive index portion 40 is a low refractive index portion in which a low refractive index substance having a refractive index smaller than that of the material constituting the optical function portion 30 exists in the space formed by the spacer portion 33 of the optical function portion 30 .

[0052] In the first embodiment, the low refractive index portion 40 is formed by filling a space formed by the spacer portion 33 of the optical function portion 30 with air (refractive index n=1.0).

[0053] Light emitted from the upper surface 22S of the wavelength conversion member 22 passes through the low refractive index portion 40 and enters the optical function unit 30, which has a refractive index higher than that of the low refractive index portion 40. Here, the light emitted from the upper surface 22S of the wavelength conversion member 22 is narrowed in the optical axis direction, which is perpendicular to the upper surface 22S of the wavelength conversion member 22, at the interface between the low refractive index portion 40 and the optical function unit 30, and then enters the optical function unit 30 (base 31). Therefore, by providing the low refractive index portion 40 between the upper surface 22S of the wavelength conversion member 22 and the lower surface of the base 31 of the optical function unit 30, it is possible to increase the narrow-angle component of the light emitted from the light emitting device 1.

[0054] In this description, the narrow-angle component of light emitted from the light emitting device 1 refers to the component of light emitted within a range of 30° with respect to the optical axis direction perpendicular to the upper surface 22 S of the wavelength conversion member 22 .

[0055] (Light Reflecting Member) The light reflecting member 50 is a light reflecting member having light reflectivity that is filled in the recess of the substrate 10 between the semiconductor light emitting element 21 and the wavelength conversion member 22 and the inner wall of the recess of the substrate 10. The light reflecting member 50 is a light reflecting member that is filled so as to cover the side surfaces of the semiconductor light emitting element 21 and the wavelength conversion member 22 and expose the upper surface 22S of the wavelength conversion member 22.

[0056] In the first embodiment, the light reflecting member 50 is made of titanium oxide (TiO ２ A light-transmitting resin material such as a silicone resin containing light-scattering particles such as .lamda.) particles was used.

[0057] The light reflecting member 50 reflects or scatters light that reaches the side surfaces of the semiconductor light emitting element 21 and the wavelength conversion member 22 from the inside so that the light returns to the inside of the light emitting element 21 and the wavelength conversion member 22. As a result, the light reflecting member 50 prevents the light that reaches the side surfaces of the semiconductor light emitting element 21 and the wavelength conversion member 22 from leaking out, and can increase the amount of luminous flux that is emitted from the upper surface 22S of the wavelength conversion member 22. In other words, by providing the light reflecting member 50, it is possible to improve the light extraction efficiency of the light emitting device 1.

[0058] As described above, the optical function section 30 is disposed so that the spacer section 33 is disposed in the region of the upper surface of the light reflecting member 50 .

[0059] For example, when the optical function unit 30 is bonded after the silicone resin of the light reflecting member 50 has hardened, the upper surface of the light reflecting member 50 after the silicone resin has hardened will have a concave surface shape due to resin shrinkage caused by effective shrinkage. At this time, when the lower surface of the spacer portion 33 of the optical function unit 30 and the upper surface of the light reflecting member 50 are bonded using adhesive, excess adhesive for bonding is stored in the concave portion of the light reflecting member 50. Therefore, the resin shrinkage of the light reflecting member 50 and the coating layer RE formed on the upper surface 22S of the wavelength conversion member 22 can prevent the excess adhesive from running onto the upper surface 22S of the wavelength conversion member 22.

[0060] Furthermore, even when the optical function part 30 is placed on the upper surface of the light reflecting member 50 before the silicone resin of the light reflecting member 50 is hardened and then the silicone resin of the light reflecting member 50 is hardened, the coating layer RE on the upper surface 22S of the wavelength conversion member 22 can prevent the silicone resin of the light reflecting member 50 from climbing up onto the upper surface 22S of the wavelength conversion member 22.

[0061] The light reflecting member 50 may be formed to extend up to a portion of the lower end region of the inner surface of the recess of the substrate 10, the outer surface of the spacer portion 33 of the optical function unit 30, and the outer surface of the base portion 31 of the optical function unit 30. In this case, the light reflecting member 50 reflects light emitted laterally from the outer surfaces of the spacer portion 33 and the base portion 31 of the optical function unit 30 inward of the optical function unit 30, thereby making it possible to suppress the emission of wide-angle components of the emitted light from the light emitting device 1 (light with directional characteristics greater than ±30° with respect to the optical axis direction). In other words, the light reflecting member 50 makes it possible to suppress the unintended emission of light, such as light from the outer surface of the spacer portion 33 of the optical function unit 30 and the side surface of the base portion 31.

[0062] In addition, by covering the side of the spacer portion 33 of the optical function portion 30 and supporting the spacer portion 33, the strength of the spacer portion 33 can be improved and damage to the spacer portion 33 due to vibration of the spacer portion 33, etc. can be suppressed.

[0063] (Function of Low Refractive Index Portion) The function of narrowing the angle of emitted light from the light emitting device 1 of the present embodiment 1 will be described with reference to FIGS.

[0064] 3 and 4 are enlarged cross-sectional views of the wavelength conversion member 22 and the optical function part 30 in the cross section of Fig. 2. Note that in order to clarify the optical paths of the emitted light LM1, LM2, and LM3 from the light emitting device 1, the coating layer RE is not shown and the optical function part 30 is not hatched.

[0065] Figure 3 shows, as a comparative example, the optical paths of the emitted light LM1, LM2, and LM3 of a light-emitting device 1A having an optical function part 30A consisting only of a base part 31A and a convex part 32, without a low refractive index part 40 between the upper surface 22S of the wavelength conversion member 22 and the lower surface of the optical function part 30.

[0066] Figure 4 is a diagram showing the optical paths of the emitted light LM1, LM2, and LM3 of the light-emitting device 1 in this embodiment 1, in which a low refractive index section 40 is provided by a spacer section 33 between the upper surface 22S of the wavelength conversion member 22 and the lower surface of the optical function section 30.

[0067] The thickness of the base 31A of the light emitting device 1A was set to the sum of the thicknesses of the base 31 and the spacer portion 33 of the light emitting device 1A.

[0068] 3 and 4, the optical path model of the emitted light LM1 to LM3 is described as a case where light emitted from a light emission point 22E on the upper surface 22S of the wavelength conversion member 22 directly below the center point of the central convex portion 32A, in other words, on the lens axis (optical axis) when the convex portion 32A is viewed as a lens, is diffused and radiated in an ideal Lambertian orientation.

[0069] 3 and 4, emitted light LM1 represents light emitted from the upper surface 22S of the wavelength conversion member 22 in a direction perpendicular to the upper surface 22S. Emitted light LM2 represents light emitted from the upper surface 22S of the wavelength conversion member 22 at an angle of 30° with respect to the perpendicular direction. Emitted light LM3 represents light emitted from the upper surface 22S of the wavelength conversion member 22 at an angle of 60° with respect to the perpendicular direction.

[0070] In Figure 3, the emitted light LM1 and LM2 is light emitted from the light emission point 22E on the upper surface 22S of the wavelength conversion member 22, enters the convex portion 32A, and is narrowed in angle by the lens effect of the surface of the convex portion 32A before being emitted from the light emitting device 1A.

[0071] However, the emitted light LM3 emitted from the light emission point 22E of the wavelength conversion member 22 at a large angle relative to the axis perpendicular to the upper surface 22S, i.e., the lens axis (optical axis) of 32A, is incident on the convex portions 32B and 32C adjacent to the convex portion 32A within the base 31A. As a result, the emitted light LM3 is refracted in a wide-angle direction (toward the side of the light-emitting device 1A) by the surfaces of the convex portions 32B and 32C, and is emitted from the light-emitting device 1A with a wide angle.

[0072] That is, when light from light emission point 22E enters convex portion 32A and exits from the surface of convex portion 32A, a lens effect occurs that refracts the light in a narrow-angle direction, and the light is refracted in a direction perpendicular to upper surface 22S. However, when light from light emission point 22E enters convex portions 32B and 32C adjacent to convex portion 32A, the lens effect of refracting the light in a narrow-angle direction does not occur, and the light is instead refracted in a wide-angle direction.

[0073] In contrast to this, in FIG. 4, light emitted from the light emission point 22E on the upper surface 22S of the wavelength conversion member 22 is incident on the lower surface of the base portion 31 of the optical function portion 30 via the low refractive index portion 40.

[0074] At this time, the emitted light beams LM1, LM2, and LM3 are narrowed in angle in the optical axis direction on the lower surface of the base 31 of the optical function section 30 according to Snell's law, and are more likely to be incident on the convex section 32A.

[0075] The outgoing light beams LM1, LM2, and LM3 incident on the convex portion 32A are narrowed in angle by the lens effect of the surface of the convex portion 32A and are then emitted from the light emitting device 1.

[0076] As shown in Figures 3 and 4, in the light-emitting device 1 of this embodiment 1, by providing a low-refractive index portion 40 between the upper surface 22S of the wavelength conversion member 22 and the lower surface of the base 31 of the optical function portion 30, it is possible to increase the narrow-angle component of the emitted light from the light-emitting device 1.

[0077] (Directional Characteristics of Emitted Light from the Light-Emitting Device of Example 1) FIG. 5 is a diagram showing the directional characteristics of emitted light from the light-emitting device 1 fabricated as a prototype with the above-described structure.

[0078] The vertical line 0-0 in Fig. 5 indicates the optical axis direction of the light emitting device 1. The fan-shaped range in Fig. 5 indicates the luminous flux ratio in the range from -90° to +90° with respect to the optical axis when the luminous flux in the optical axis direction is set to 100%.

[0079] As shown in Figure 5, the light emitting device 1 of this Example 1 resulted in a large ratio of narrow-angle luminous flux to total luminous flux (the ratio of luminous flux amount in the range of -30° to +30° in the optical axis direction to total luminous flux).

[0080] The narrow-angle luminous flux ratio of the light-emitting device 1 of this Example 1 was 137% of the narrow-angle luminous flux ratio of the light-emitting device having the directional characteristics of ideal Lambertian orientation, when the narrow-angle luminous flux ratio of a light-emitting device having the same optical output as the light-emitting device 1 and whose emitted light has the directional characteristics of ideal Lambertian orientation was taken as 100%.

[0081] Therefore, by providing a low refractive index portion 40 between the upper surface 22S of the wavelength conversion member 22 and the lower surface of the base 31 of the optical function portion 30, it is possible to increase the proportion of narrow-angle luminous flux of the emitted light from the light emitting device 1.

[0082] (Verification of the thickness of the low refractive index section) Figure 6 shows the simulation results of the luminous flux ratio of the narrow-angle component of light emitted from the light-emitting device 1 when the height of the spacer section 33 of the optical function section 30, i.e., the thickness T2 of the low refractive index section 40, is changed.

[0083] In Figure 6, as in Example 1 above, the light-emitting unit 20 was simulated as a square with a side length D1 of 1.0 mm on the light-emitting surface of the semiconductor light-emitting element 21 and a square with a side length D2 of 0.85 mm on the upper surface 22S of the wavelength conversion member 22.

[0084] 6, the simulation was performed on the assumption that the external shape of the base 31 of the optical function part 30 was a square with sides of 1.0 mm, the radius R1 of the convex parts 32 was 16.5% of the length of one side of the upper surface of the base 31, and they were arranged in a matrix of 3 rows and 3 columns on the base 31. The simulation was also performed on the assumption that the thickness T1 of the base 31 of the optical function part 30 was 5% of the length of one side of the upper surface of the base 31, i.e., the thickness T1 of the base 31 was 50 μm.

[0085] In other words, in this simulation, the thickness of the low refractive index portion 40 was varied using the height of the spacer portion 33 as a parameter in the structure of the first embodiment.

[0086] 6 represents the ratio of the thickness T2 of the low refractive index portion 40 to the length of one side of the upper surface of the base 31 of the optical function portion 30. The point on the horizontal axis of Fig. 6 where the ratio of the thickness T2 of the low refractive index portion 40 is 0% represents a state in which the low refractive index portion 40 is not present in the light emitting device 1, that is, a state in which the spacer portion 33 is not provided and the lower surface of the base 31 is in contact with the upper surface 22S of the wavelength conversion member 22.

[0087] As described above, in this simulation, the thickness T1 of the base 31 of the optical function unit 30 and the thickness T2 of the low refractive index unit 40 are simulated at a ratio based on the length of one side of the top surface of the base 31. For example, when the size of the light emitting surface of the light emitting device 1, i.e., the length of one side of the outer shape of the base 31, changes, the radius of the convex portion 32 also changes accordingly. Therefore, the incidence area of ​​the light emitted from the top surface 22S of the wavelength conversion member 22 onto each of the convex portions 32 also changes, and therefore the optimal values ​​of the thickness T1 of the base 31 of the optical function unit 30 and the thickness T2 of the low refractive index unit 40 also change according to the size of the light emitting surface of the light emitting device 1.

[0088] The vertical axis of Fig. 6 shows the luminous flux ratio within a narrow angle range (±30°) when the ratio of the thickness T2 of the low refractive index portion 40 is changed. Note that on the vertical axis of Fig. 6, the luminous flux amount within a narrow angle in a light emitting device that does not include the optical function portion 30 and that emits light with directional characteristics of ideal Lambertian orientation from the top surface of the wavelength conversion member is set to 100%. In the light emitting device that emits light with directional characteristics of ideal Lambertian orientation, the top surface of the wavelength conversion member has a square shape with sides of 1.0 mm.

[0089] As shown in FIG. 6, by providing the low refractive index portion 40 between the upper surface 22S of the wavelength conversion member 22 and the lower surface of the base portion 31, the narrow-angle luminous flux ratio increases.

[0090] Specifically, when the ratio of the thickness T2 of the low refractive index portion 40 to the length of one side of the upper surface of the base 31 of the optical function portion 30 was in the range of 0.01% to 22.8%, the narrow-angle luminous flux ratio was 110% or more. Furthermore, when the ratio of the thickness T2 of the low refractive index portion 40 to the length of one side of the upper surface of the base 31 of the optical function portion 30 was in the range of 0.6% to 9.4%, the narrow-angle luminous flux ratio was 130% or more.

[0091] Furthermore, when the ratio of the thickness T2 of the low refractive index portion 40 to the length of one side of the top surface of the base 31 of the optical function portion 30 was 5%, the narrow angle luminous flux ratio was 138%, the largest.

[0092] Therefore, in the light-emitting device 1 of this Example 1, it was found that the thickness T2 of the low refractive index section 40 that is preferable for increasing the narrow-angle luminous flux ratio of the light extracted from the light exit surface of the optical function section 30 is in the range of 0.1% or more and 20% or less of the length of one side of the upper surface of the base 31 of the optical function section 30, and in particular, in the range of 0.1% or more and 10% or less.

[0093] That is, when the external shape of the base 31 of the optical function part 30 is a square of 1.0 mm on each side, the thickness T2 of the low refractive index part 40 that is preferable for increasing the narrow-angle luminous flux ratio of the light extracted from the light exit surface of the optical function part 30 is in the range of 0.001 mm or more and 0.2 mm or less, particularly in the range of 0.001 mm or more and 0.1 mm or less.

[0094] (Verification of Thickness of Base of Optical Function Unit) FIG. 7 is a diagram showing the results of a simulation of the luminous flux ratio of the narrow-angle component of light emitted from the light emitting device 1 when the thickness T1 of the base 31 of the optical function unit 30 is changed.

[0095] 7, the simulation was performed based on the simulation results shown in Fig. 6, with the ratio of the total thickness of the thickness T1 of the base 31 and the thickness T2 of the low refractive index portion 40 being set to 10% with respect to the length of one side of the top surface of the base 31 of the optical function portion 30. The other structures of the light-emitting device 1 are the same as those described in Fig. 6.

[0096] 7 represents the ratio of the thickness T1 of the base 31 to the length of one side of the upper surface of the base 31 of the optical function unit 30. The upper vertical axis of Fig. 7 represents the ratio of the thickness T2 of the low refractive index unit 40 to the length of one side of the upper surface of the base 31 of the optical function unit 30.

[0097] 7, the simulation was performed by varying the ratio of the thickness T1 of the base 31 to the length of one side of the upper surface of the base 31 of the optical function part 30 from 5% to 10%. That is, as the ratio of the thickness T1 of the base 31 varies, the ratio of the total thickness T2 of the low refractive index part 40 to the length of one side of the upper surface of the base 31 of the optical function part 30 varies from 5% to 0%.

[0098] The vertical axis of Fig. 7 shows the luminous flux ratio within a narrow angle range (±30°) when the ratio of the thickness T1 of the base 31 is changed. As in Fig. 6, the vertical axis of Fig. 7 represents the luminous flux amount within a narrow angle of 100% in a light emitting device that does not include the optical function unit 30 and that emits light with directional characteristics of ideal Lambertian orientation from the top surface of the wavelength conversion member. In the light emitting device that emits light with directional characteristics of ideal Lambertian orientation, the top surface of the wavelength conversion member has a square shape with sides of 1.0 mm.

[0099] As shown in FIG. 7, the narrow-angle luminous flux ratio was 130% or more over the entire simulation range of 5 to 10% of the ratio of the thickness T1 of the base portion 31 of the optical function portion 30.

[0100] Furthermore, the narrow-angle luminous flux ratio reached its maximum value of 138% when the thickness T1 of the base 31 of the optical function part 30 was 5%. It was also found that the narrow-angle luminous flux ratio tended to decrease as the thickness T1 of the base 31 of the optical function part 30 was increased from 5%.

[0101] Therefore, in the light-emitting device 1 of this Example 1, the thickness T1 of the base 31 that is preferable for increasing the narrow-angle luminous flux ratio of the light extracted from the light exit surface of the optical function unit 30 can be any thickness within the range of 5% to 10% of the length of one side of the top surface of the base 31 of the optical function unit 30, which is within the range in which the simulation was performed.

[0102] Within the range of the simulation, it was found that a ratio of 5% to the thickness T1 of the base 31, i.e., a thickness equivalent to the thickness T2 of the low refractive index portion 40, was most effective in terms of the narrow-angle luminous flux ratio.

[0103] (Verification of the radius of the convex portion of the optical function portion) Figure 8 is a graph showing the results of a simulation of the narrow-angle luminous flux ratio of the light-emitting device 1 when the radius R1 of the convex portion 32 is varied in Example 1, when the convex portions 32 are arranged in a matrix of 3 rows and 3 columns, totaling 9, on the upper surface of the base 31 of the optical function portion 30.

[0104] The horizontal axis of FIG. 8 represents the ratio of the radius R1 of the convex portion 32 to the length of one side of the top surface of the base 31 of the optical function unit 30. In FIG. 8, a simulation was performed by varying the ratio of the radius R1 of the convex portion 32 to the length of one side of the top surface of the base 31 of the optical function unit 30 from 0% to 40%. That is, a position where the ratio of the radius R1 of the convex portion 32 is 0% represents a state where no convex portion 32 is formed on the optical function unit 30. Furthermore, when the ratio of the radius R1 of the convex portion 32 is 16.5% or more, convex portions 32 adjacent to each other in the XY direction overlap in a top view. When the ratio is 23.6% or more, two adjacent convex portions 32 that are higher in the diagonal direction of the top surface of the base 31 overlap each other.

[0105] The vertical axis of Fig. 8 shows the luminous flux ratio within a narrow angle range (±30°) when the ratio of the radii R1 of the convex portions 32 is changed. Note that, on the vertical axis of Fig. 8, the luminous flux amount within a narrow angle in a light emitting device that does not include the optical function unit 30 and that emits light with ideal Lambertian orientation directional characteristics from the top surface of the wavelength conversion member is set to 100%. In the light emitting device that emits light with ideal Lambertian orientation directional characteristics, the top surface of the wavelength conversion member is a square with sides of 1.0 mm.

[0106] 8, when the ratio of the radius R1 of the convex portion 32 was in the range of 10% to 30%, the luminous flux ratio within the narrow angle was 110% or more. Furthermore, when the ratio of the radius R1 of the convex portion 32 was in the range of 15% to 22%, the luminous flux ratio within the narrow angle was 130% or more. Furthermore, the luminous flux ratio within the narrow angle reached a maximum value of 139% when the ratio of the radius R1 of the convex portion 32 was 17.5%.

[0107] From the simulation results of Figure 8, it was found that forming the convex portions 32 with a radius R1 that is such a dimension that, when viewed from above, adjacent convex portions 32 partially overlap each other in the XY direction, but adjacent convex portions 32 do not overlap each other in the diagonal direction on the top surface of the base 31, is most effective for the narrow-angle performance of the optical function portion 30.

[0108] In other words, it has been found that it is preferable to have a small exposed area of ​​the flat surface, which is the upper surface of the base 31 on the upper surface of the optical function portion 30. It has also been found that it is preferable that adjacent convex portions 32 do not overlap each other to the extent that the hemispherical surfaces, which are the surfaces of the convex portions 32, do not impair the lens effect.

[0109] (Verification of the number of convex portions arranged in the optical function portion) In the first embodiment, a case has been described in which the convex portions 32 are arranged in a matrix of three rows and three columns, a total of nine convex portions 32, on the upper surface of the base portion 31 of the optical function portion 30. However, the number of convex portions 32 arranged in the optical function portion 30 is not limited to this.

[0110] 9 and 10 are diagrams for explaining a simulation of the narrow-angle luminous flux ratio when the number of convex portions 32 arranged on the upper surface of the base portion 31 of the optical function portion 30 is arranged in a matrix with a different number of arrangements.

[0111] In this simulation, the number of arrangements of the convex portions 32 on the upper surface of the base portion 31 of the optical function portion 30 was varied from 1 row and 1 column to 7 rows and 7 columns.

[0112] In this simulation, the radius R1 of the convex portion 32 is determined by dividing the top surface of the base 31 of the optical function unit 30 into equal sections in the X and Y directions from 1 row and 1 column (1 section in total) to 7 rows and 7 columns (49 sections in total), with the center point P1 of each section being positioned as the center point of each convex portion 32.

[0113] The simulation was also performed with each of the convex portions 32 having a radius R1 that extends from the center point P1 to the end of the corresponding compartment. That is, when one convex portion 32 is formed in each compartment with one row and one column, the radius of the convex portion 32 is 50% of the length of one side of the upper surface of the base 31 of the optical function unit 30, and when 49 convex portions 32 are formed in each compartment with seven rows and seven columns, the radius of the convex portion 32 is approximately 7.1% of the length of one side of the upper surface of the base 31 of the optical function unit 30. Therefore, this simulation was performed assuming that adjacent convex portions 32 do not overlap each other when viewed from above.

[0114] FIG. 9 is a diagram showing a top view of a light emitting device 1B in which, for example, 49 convex portions 32 are formed in a 7-row, 7-column section.

[0115] Figure 10 is a graph showing the results of a simulation of the narrow-angle luminous flux ratio of the light-emitting device 1B when the radius R1 of the convex portion 32 is varied, when a total of nine convex portions 32 are arranged in a matrix of three rows and three columns on the upper surface of the base 31 of the optical function portion 30.

[0116] The horizontal axis in FIG. 10 indicates the total number of convex portions 32 when the number of arrangements of the convex portions 32 on the upper surface of the base portion 31 of the optical function portion 30 is varied from 1 row and 1 column to 7 rows and 7 columns.

[0117] The vertical axis of Fig. 10 shows the luminous flux ratio within a narrow angle range (±30°) when the number of arrangements of the convex portions 32 is changed. Note that, on the vertical axis of Fig. 10, the luminous flux amount within a narrow angle in a light emitting device that does not include the optical function unit 30 and that emits light with directional characteristics of ideal Lambertian orientation from the top surface of the wavelength conversion member is set to 100%. In the light emitting device that emits light with directional characteristics of ideal Lambertian orientation, the top surface of the wavelength conversion member is a square with sides of 1.0 mm.

[0118] 10 , the narrow-angle luminous flux ratio was 110% or more in any simulation range for the number of arranged convex portions 32. Furthermore, the narrow-angle luminous flux ratio was 130% or more when the number of arranged convex portions 32 was 4 (2 rows and 2 columns), 9 (3 rows and 3 columns), and 16 (4 rows and 4 columns). Furthermore, the narrow-angle luminous flux ratio reached a maximum of 137% when the number of arranged convex portions 32 was 9 (3 rows and 3 columns).

[0119] From the simulation results of Figure 10, it was found that the narrow angle performance of the optical function part 30 is most effective when the convex parts 32 are arranged in a matrix of 3 rows and 3 columns, totaling 9, on the upper surface of the base 31 of the optical function part 30.

[0120] (Verification of Addition of Second Convex Portions to Optical Function Unit) In Example 1, a case has been described in which the convex portions 32 of the same shape are arranged in a matrix on the upper surface of the base portion 31 of the optical function unit 30. However, the arrangement of the convex portions 32 of the optical function unit 30 is not limited to this.

[0121] Figures 11 and 12 are diagrams showing a simulation of the narrow-angle luminous flux ratio when first convex portions 32 are arranged in a matrix on the upper surface of the base 31 of the optical function part 30, and second convex portions 34 are arranged in the gap regions between the first convex portions 32 on the upper surface of the base 31.

[0122] In other words, the convex portions of the optical function part 30 of the light emitting device 1 may have a structure including first convex portions 32 arranged in a matrix on the base and second convex portions 34 arranged in the regions between the rows and columns of the matrix arrangement of the first convex portions 32.

[0123] In this simulation, the first convex portions 32 are arranged in a matrix of 3 rows and 3 columns on the upper surface of the base 31 of the optical function unit 30, as in Example 1, with a radius R1 that is 16.5% of the length of one side of the upper surface of the base 31 of the optical function unit 30. The second convex portions 34 are formed in a hemispherical shape with a radius R2 at the center point P2 of the gap region of the first convex portions 32.

[0124] In addition, in this simulation, the narrow-angle luminous flux ratio of the light emitting device 1C is simulated when the radius R2 of the second convex portion 34 is changed.

[0125] Figure 11 is a diagram showing a top view of a light-emitting device 1C in which, for example, when the first protrusions 32 are arranged in a matrix of 3 rows and 3 columns, the second protrusions 34 are arranged in a matrix of 3 rows and 3 columns in the gap regions of the first protrusions 32.

[0126] 12 is a diagram showing a simulation of the narrow-angle luminous flux ratio of the light emitting device 1C when the radius R2 of the second convex portion 34 is varied. Note that the ratio of the radius R1 of the first convex portion 32 was fixed at 16.5%, as in Example 1.

[0127] The horizontal axis in Figure 12 represents the ratio of the radius R2 of the second convex portion 34 to the length of one side of the upper surface of the base 31 of the optical function unit 30. In Figure 12, a simulation was performed by varying the ratio of the radius R2 of the second convex portion 34 to the length of one side of the upper surface of the base 31 of the optical function unit 30 from 0% to 20%. That is, at a position where the ratio of the radius R2 of the second convex portion 34 is 0%, the second convex portion 34 is not formed on the optical function unit 30, and only the first convex portion 32 contributes to narrowing the angle of the emitted light of the light-emitting device 1C. Furthermore, when the ratio of the radius R2 of the second convex portion 34 is approximately 6.8% or more, adjacent first convex portions 32 overlap in a top view.

[0128] The vertical axis of Fig. 12 shows the luminous flux ratio within a narrow angle range (±30°) when the ratio of the radii R2 of the second convex portions 34 is changed. Note that, on the vertical axis of Fig. 12, the luminous flux amount within a narrow angle in a light emitting device that does not include the optical function unit 30 and that emits light with directional characteristics of ideal Lambertian orientation from the top surface of the wavelength conversion member is set to 100%. In the light emitting device that emits light with directional characteristics of ideal Lambertian orientation, the top surface of the wavelength conversion member has a square shape with sides of 1.0 mm.

[0129] 12, when the ratio of the radius R2 of the second convex portion 34 was in the range of 0% to 17.3%, the luminous flux ratio within the narrow angle was 130% or more. Furthermore, the luminous flux ratio within the narrow angle reached a maximum value of 140% when the ratio of the radius R2 of the second convex portion 34 was approximately 6%.

[0130] Furthermore, when the ratio of the radius R2 of the second convex portion 34 is in the range of approximately 8% or more, the narrow-angle luminous flux ratio tends to decrease compared to when the second convex portion 34 is not formed (the ratio of the radius R2 of the second convex portion 34 is 0%).

[0131] From the simulation results of FIG. 12, it is considered that forming the second convex portion 34 so that it does not overlap with the first convex portion 32 when viewed from above is effective in improving the narrow angle performance of the optical function portion 30.

[0132] (Modifications) Modifications of the light emitting device 1 according to the first embodiment of the present invention will be described below.

[0133] (Modification 1) Fig. 13 is a top view of a light emitting device 1D according to Modification 1. Fig. 14 is a cross-sectional view taken along line BB of the light emitting device 1 shown in Fig. 13. Fig. 15 is a cross-sectional view taken along line CC of the light emitting device 1 shown in Fig. 13.

[0134] The light emitting device 1D of Modification 1 has a configuration basically similar to that of the light emitting device 1 of Example 1. The light emitting device 1D of Modification 1 differs from Example 1 in that the convex portions 35 formed on the upper surface of the base 31 of the optical function unit 30D protrude upward and have a semi-cylindrical shape extending to both ends of a pair of opposing sides of the upper surface of the base 31. In other words, the convex portions 35 are cylindrical lenses formed on the upper surface of the base 31 of the optical function unit 30D.

[0135] In this embodiment 1, as shown in Figures 13 and 14, the convex portion 35 is a cylindrical lens extending in the Y direction, with its bottom surface being a surface along a pair of sides parallel to the Y direction on the upper surface of the base 31 of the optical function portion 30D.

[0136] 15 , the convex portion 35 has a semicircular bottom surface with a radius R1 extending from the top surface of the base 31 of the optical function unit 30D. In this example, the radius R1 of the bottom surface of the convex portion 35 is set to 16.5% of the length of one side of the top surface of the base 31 of the optical function unit 30D. The convex portions 35 are arranged as three cylindrical lenses in the X direction on the top surface of the base 31.

[0137] Forming a semi-cylindrical lens on the upper surface of the base 31 of the optical function unit 30D makes it possible to control the directivity characteristics in the X and Y directions. For example, this is useful when it is necessary to narrow the angle of the light emitted from the light emitting device 1D only in the X direction.

[0138] The convex portion 35 may be extended in the X direction. The corners EG of the cylindrical lens shown in Fig. 14 may be chamfered, for example, by rounding.

[0139] Furthermore, in the light-emitting device 1D, when it is necessary to individually control the emitted light in the X direction and the Y direction, the convex portion 35 is not limited to a cylindrical lens, and an elliptical lens, aspherical lens, or the like may be used. Furthermore, the convex portion 35 may be in the shape of a cone or a frustum. In this case, the convex portions 35 may be arranged in a matrix on the base portion 31 as in the first embodiment.

[0140] (Modification 2) Furthermore, as in a light emitting device 1E according to Modification 2 shown in FIG. 16, the wavelength conversion member 23 of the light emitting section 20A may be formed in a columnar shape without any inclined side surfaces.

[0141] In this case, if the top surface shape (light-emitting region) of the semiconductor light-emitting element 21 is a square with a side length D1 of 1.0 mm, the top surface shape of the wavelength conversion member 23 will also be a square with a side length D2 of 1.0 mm. Therefore, in the light-emitting device 1E, the outer surfaces of the optical function unit 30 mounted on the wavelength conversion member 23, the wavelength conversion member 23, and the semiconductor light-emitting element 21 are substantially aligned in top view.

[0142] Furthermore, like the light emitting device 1E according to the second modification, the spacer portion 33 of the optical function portion 30 can be bonded onto the upper surface 23S of the wavelength conversion member 23 along the outer edge of the upper surface 23S.

[0143] In the light emitting device 1E according to the second modification, when viewed from above, the outer edge of the upper surface of the light emitting unit 20A (i.e., the outer edge of the upper surface of the wavelength converting member 23) is located at the outer edge of the convex portion 32 arranged on the outermost periphery and the outer edge of the optical function unit 30. That is, in the first embodiment, when viewed from above, the outer edge end of the optical function unit 30 is located outside the outer edge of the upper surface of the light emitting unit 20 (i.e., the outer edge of the upper surface of the wavelength converting member 22). This allows the shape of the light source image projected from the light emitting device 1E to be very close to the shape of the upper surface of the light emitting unit 20A.

[0144] Light emitted from the region of the upper surface 23S of the wavelength conversion member 23 excluding the region where the spacer portion 33 is bonded is incident on the lower surface of the base portion 31 of the optical function portion 30 via the low refractive index portion 40, as in Example 1. Therefore, the light emitting device 1E can narrow the angle of emitted light.

[0145] As explained in Example 1, the spacer portion 33 of the optical function unit 30 has a narrow width of approximately 50 μm. Therefore, most of the light incident on the spacer portion 33 from the upper surface 23S of the wavelength conversion member 23 is totally reflected by the side surfaces within the spacer portion 33 and guided to the convex portion 32, increasing the probability that the light will be emitted from the surface of the convex portion 32 as light within a narrow angle range.

[0146] In the light emitting device 1E, for example, the spacer portion 33 and the wavelength conversion member 23 can be bonded together by an appropriate method such as surface activated bonding without using a light-transmitting adhesive.

[0147] For example, a flat silicone resin body having spacer portions 33 formed in a lattice pattern on the underside thereof and a flat alumina material containing phosphor particles are bonded by surface activated bonding. At this time, silicon oxide (SiO ２ A bonding film (not shown) for performing surface activation bonding such as a SiO 2 film is formed on the substrate.

[0148] After surface activation bonding of the alumina material and the silicone resin body, for example, a convex portion 32 is formed on the upper surface of the silicone resin body using an imprint method. This is then divided into individual pieces by dicing or the like to form a composite of the pre-bonded wavelength conversion member 23 and optical function unit 30. Bonding this composite onto the semiconductor light emitting element 21 can simplify the manufacturing process of the light emitting device 1E.

[0149] In addition, the spacer portion 33 formed along the outer edge of the lower surface of the base portion 31 is joined to the outer edge of the upper surface 23S of the wavelength conversion member 23 by surface activated bonding, so that the low refractive index portion 40 becomes an airtight space formed by the optical function portion 30 and the wavelength conversion member 23.

[0150] This makes it possible to prevent the raw resin of the light reflecting member 50 from climbing up onto the upper surface 22S of the wavelength conversion member 22 when filling the recess in the substrate 10, and therefore makes it possible to omit forming a coating layer RE such as a fluorine film that has low affinity with the resin material on the upper surface 23S of the wavelength conversion member 23.

[0151] (Variation 3) Furthermore, as in a light emitting device 1F according to Variation 3 shown in FIG. 17, when viewed from above, the outer edge shape of the optical function unit 30 may be larger than the outer edge shapes of the semiconductor light emitting element 21 and the wavelength conversion member 23 of the light emitting unit 20A.

[0152] As in the first embodiment, the light emitted from the upper surface 23S of the wavelength conversion member 23 is incident on the lower surface of the base 31 of the optical function unit 30 via the low refractive index portion 40. Therefore, the light emitting device 1F can narrow the angle of the emitted light.

[0153] In this case, the spacer portion 33 of the optical function portion 30 is bonded to the upper surface of the light reflecting member 50. Therefore, the light emitting device 1F can be manufactured by the same manufacturing method as the light emitting device 1 of the first embodiment.

[0154] In the light emitting device 1F, the length of one side of the outer edge of the base 31 of the optical function section 30 may be increased, and the length of one side of the outer edges of the semiconductor light emitting element 21 and the wavelength conversion member 23 may be decreased.

[0155] Furthermore, like the light emitting device 1E of Modification Example 2 and the light emitting device 1F of Modification Example 3, the lower surface of the spacer portion 33 of the optical function unit 30 is not limited to being in contact with only one of the upper surface 22S of the wavelength conversion member 22 or the upper surface of the light reflecting member 50, but may be in contact with both the upper surface 22S of the wavelength conversion member 22 and the upper surface of the light reflecting member 50. In other words, the lower surface of the spacer portion 33 may at least partially overlap with the upper surface 22S of the wavelength conversion member 22 of the light emitting unit 20 in a top view.

[0156] (Variation 4) Furthermore, as in the light emitting device 1G according to Variation 4 shown in FIG. 18, when viewed from above, the outer edge shape of the optical function unit 30 may be smaller than the outer edge shapes of the semiconductor light emitting element 21 and the wavelength conversion member 23 of the light emitting unit 20A.

[0157] In this case, the inclination angle of the inclined side surfaces of the wavelength conversion member 22 may be increased so that the outer edge shape of the upper surface 22S of the wavelength conversion member 22 when viewed from above is smaller than the outer edge shape of the optical function portion 30.

[0158] As in the first embodiment, the light emitted from the upper surface 22S of the wavelength conversion member 22 is incident on the lower surface of the base 31 of the optical function unit 30 via the low refractive index portion 40. Therefore, the light emitting device 1G can narrow the angle of the emitted light.

[0159] Increasing the size difference between the lower surface and upper surface 22S of the wavelength conversion member 22 improves the light-collecting effect of the wavelength conversion member 22, that is, the total luminous flux of the light emitted from the light emitting device 1G can be increased.

[0160] As explained in the light emitting device 1E of the modified example 2 and the light emitting device 1F of the modified example 3, the outer edge shape of the optical function part 30 may be equal to or larger than the upper surface 22S of the wavelength conversion member 22 when viewed from above.

[0161] When the outer edge shape of the optical function part 30 when viewed from above is larger than the upper surface 22S of the wavelength conversion member 22, i.e., when the spacer part 33 of the optical function part 30 is arranged on the upper surface of the light-reflecting member 50, the light-emitting device 1G can be manufactured using the same manufacturing method as the light-emitting device 1 of Example 1.

[0162] Furthermore, when the outer edge shape of the optical function part 30 in top view is approximately the same as that of the upper surface 22S of the wavelength conversion member 22, i.e., when the spacer part 33 of the optical function part 30 is arranged in an area along the outer edge of the upper surface 22S of the wavelength conversion member 22, the formation of a coating layer RE such as a fluorine film may be omitted, and the spacer part 33 of the optical function part 30 and the upper surface 22S of the wavelength conversion member 22 may be joined by surface activated bonding.

[0163] In addition, in the light emitting device 1G, the outer edge shapes of the upper surface 22S of the wavelength conversion member 22 and the optical function part 30 when viewed from above may be made smaller, or the outer edge shapes of the semiconductor light emitting element 21 and the lower surface of the wavelength conversion member 23 when viewed from above may be made smaller.

[0164] (Modification 5) As in a light emitting device 1H according to Modification 5 shown in FIG. 19, the wavelength conversion member 24 that converts the wavelength of light emitted from the semiconductor light emitting element 21 may be formed of other materials.

[0165] The light-emitting section 20B of the light-emitting device 1H of variant example 5 has a wavelength conversion member 24 made of wavelength conversion resin 24A and spherical particles 24B dispersed in the wavelength conversion resin 24A on a semiconductor light-emitting element 21, and a translucent member 25 arranged on the wavelength conversion member 24.

[0166] The wavelength converting resin 24A is made of a translucent thermosetting resin such as a silicone resin containing particles of a YAG:Ce phosphor. The spherical particles 24B are made of, for example, glass beads or silicone resin particles and are dispersed in the wavelength converting resin 24A.

[0167] The light-transmitting member 25 has an upper surface 25S, which is a light-emitting surface, and is made of a light-transmitting material such as a silicate glass plate. The lower surface, which is a light-incident surface, of the light-transmitting member 25 is bonded to the upper surface of the semiconductor light-emitting element 21 by a thermosetting resin contained in the wavelength converting resin 24A.

[0168] The spherical particles 24B function as spacers that separate the upper surface of the semiconductor light emitting element 21 and the lower surface of the light transmitting member 25 by a predetermined distance.

[0169] In the light emitting device 1H, for the same reason as explained in the second modification, it is possible to narrow the angle of the light emitted from the light emitting device 1H.

[0170] The spacer portion 33 of the optical function portion 30 and the upper surface 25S of the light-transmitting member 25 may be bonded by surface activated bonding to form a composite of the light-transmitting member 25 and the optical function portion 30. By using a silicate glass plate for the light-transmitting member 25, for example, silicon oxide (SiO ２ Therefore, it is possible to omit the formation of a bonding film for performing surface activation bonding of a film such as a SiO 2 film, thereby simplifying the manufacturing method of the light emitting device 1H.

[0171] The light emitting device 1H can be manufactured by, for example, bonding the semiconductor light emitting element 21 to the bottom surface of the recess in the substrate 10, and then applying a precursor of the wavelength conversion resin 24A having spherical particles 24B dispersed therein to the upper surface of the semiconductor light emitting element 21. Thereafter, the composite of the light-transmitting member 25 and the optical function unit 30 is placed in contact with the precursor of the wavelength conversion resin 24A applied to the semiconductor light emitting element 21, and heating is performed to thermally cure the precursor of the wavelength conversion resin 24A.

[0172] In the light emitting device 1H, the outer edge shape of the optical function unit 30 may be larger than that of the light-transmitting member 25 when viewed from above. That is, the spacer portion 33 of the optical function unit 30 may be disposed on the upper surface of the light reflecting member 50.

[0173] (Variation 6) Furthermore, as in the light-emitting device 1I according to Variation 6 shown in FIG. 20 , the side surfaces of the semiconductor light-emitting element 21 and the wavelength conversion member 22 may be covered with a light-guiding section 70 made of a light-transmitting resin, and a light-reflecting member 50 may be formed on the upper surface of the light-guiding section 70.

[0174] In this case, it is preferable that the light reflecting member 50 is formed so as to cover the outer surface of the spacer portion 33 of the optical function portion 30 and a part of the area extending from the lower end of the side surface of the base portion 31 .

[0175] This enables the light emitting device 1I to block light from the outer surface of the spacer portion 33 of the optical function portion 30 and the side surface of the base portion 31, thereby suppressing the emission of light from unintended parts of the light emitting device 1I.

[0176] (Seventh Modification) Furthermore, as in a light emitting device 1J according to a seventh modification shown in FIG. 21, when wavelength conversion of light emitted from the semiconductor light emitting element 21 is not performed, the wavelength conversion member 22 does not need to be provided.

[0177] 21 , in the light emitting device 1J, the shape of the outer edge of the optical function unit 30 in a top view substantially coincides with the outer edge of the upper surface 21S of the semiconductor light emitting element 21. In other words, the spacer unit 33 of the optical function unit 30 is disposed on the upper surface 21S of the semiconductor light emitting element 21.

[0178] For the same reasons as those explained in the second modification, the light emitting device 1J can narrow the angle of the light emitted from the light emitting device 1J.

[0179] The upper surface 21S of the semiconductor light emitting element 21 and the lower surface of the spacer portion 33 of the optical function portion 30 can be bonded by surface activated bonding.

[0180] For example, a flat silicone resin body having spacer portions 33 formed in a grid pattern on the underside thereof can be bonded to a group of semiconductor light emitting elements 21 in a wafer state by surface activated bonding.

[0181] Usually, the growth substrate on the upper surface side of the flip-chip type semiconductor light emitting element 21 is made of sapphire (Al ２ O ３ Therefore, the upper surface 21S of the semiconductor light emitting elements 21 in the wafer state is made of silicon oxide (SiO ２ This makes it possible to perform surface activation bonding directly with a silicone resin body without forming a bonding film for performing surface activation bonding such as a film.

[0182] Furthermore, when using a semiconductor light emitting element 21 having a non-transparent support substrate and a semiconductor structure layer provided in one region on the upper surface of the support substrate, a silicon oxide (SiO ２ Therefore, the upper surface 21S including the semiconductor structure layer of the semiconductor light emitting element 21 can also be directly surface activated bonded to the silicone resin body.

[0183] (Modification 8) Furthermore, like a light emitting device 1K according to Modification 8 shown in FIG. 22, the outer edge shape of the optical function portion 30 may be larger than the outer edge shape of the upper surface 21S of the semiconductor light emitting element 21 when viewed from above.

[0184] As in the first embodiment, the light emitted from the upper surface 21S of the semiconductor light emitting element 21 is incident on the lower surface of the base 31 of the optical function unit 30 via the low refractive index portion 40. Therefore, the light emitting device 1K can narrow the angle of the emitted light.

[0185] In the light emitting device 1J of the seventh modification and the light emitting device 1K of the eighth modification, a glass plate may be provided on the upper surface of the semiconductor light emitting element 21, as in the light emitting device 1H of the fifth modification.

[0186] 23 , a spacer portion for forming the low refractive index portion 40 may be integrally formed on the upper surface 22S of the wavelength conversion member 22. In the light emitting device 1L according to the 9th modification, the wavelength conversion member 22 can be processed to form a space for forming the low refractive index portion 40, and therefore the shape, size, and thickness of the low refractive index portion 40 can be stably determined.

[0187] In the light emitting device 1L of the ninth modification, a spacer portion 26 that protrudes upward is formed in a region along the outer edge of the upper surface 22S of the wavelength conversion member 22. In other words, the spacer portion 33 is a protrusion that protrudes upward from the upper surface 22S of the wavelength conversion member 22 of the light emitting unit 20.

[0188] Furthermore, the spacer portion 33 is not integrally formed on the lower surface of the base portion 31 of the optical function portion 30 , and the lower surface of the optical function portion 30 is a flat surface constituted only by the lower surface of the base portion 31 .

[0189] For example, the spacer portion 26 of the wavelength conversion member 22 is formed to have a width of approximately 50 μm, similar to the spacer portion 33 of Example 1. Furthermore, as described in Fig. 6, the height of the spacer portion 26 of the wavelength conversion member 22 is preferably formed so that the thickness T of the low refractive index portion 40 is in the range of 0.1% to 20% of the length of one side of the upper surface of the base 31 of the optical function portion 30, in particular, in the range of 0.1% to 10%.

[0190] 23 , the light reflecting member 50 is formed up to the upper end of the outer surface of the spacer portion 26 of the wavelength conversion member 22. In other words, the spacer portion 26 of the wavelength conversion member 22 is supported by the light reflecting member 50. This improves the rigidity of the spacer portion 26 of the wavelength conversion member 22, making it possible to prevent damage to the spacer portion 26 due to stress caused by thermal expansion when the light emitting device 1L is driven or external vibrations, etc.

[0191] Furthermore, because the lower surface of the optical function part 30 is flat, the lower surface of the optical function part 30 contacts the area extending from the upper surface of the spacer part 26 of the wavelength conversion member 22 to the upper surface of the light reflecting member 50. This increases the bonding area between the lower surface of the optical function part 30 and the upper surface of the spacer part 26 of the wavelength conversion member 22 and the upper surface of the light reflecting member 50, thereby increasing the bonding strength of the optical function part 30.

[0192] (Variant 10) Furthermore, as in the light-emitting device 1M according to variant 10 shown in FIG. 24 , spacer portions for forming the low refractive index portion 40 may be formed on both the lower surface of the base 31B of the optical function portion 30 and the upper surface 22S of the wavelength conversion member 22.

[0193] In this case, it is preferable that the total height of the spacer portion 33 of the optical function portion 30 and the height of the spacer portion 26 of the wavelength conversion member 22 is formed so that the thickness T of the low refractive index portion 40 is in the range of 0.1% to 20% of the length of one side of the upper surface of the base 31B of the optical function portion 30, particularly in the range of 0.1% to 10%.

[0194] The height of the spacer portion 33 of the optical function portion 30 and the height of the spacer portion 26 of the wavelength conversion member 22 may be formed to be the same height, or the height of one of the spacer portion 26 or the spacer portion 33 may be formed to be greater.

[0195] (Modification 11) As in a light emitting device 1N according to modification 11 shown in Figures 25 and 26, a through hole 31H may be formed that penetrates from the upper surface to the lower surface of the base 31B of the optical function part 30E when viewed from above.

[0196] Fig. 25 is a top view of a light emitting device 1N according to Modification 11. Fig. 26 is a cross-sectional view of the light emitting device 1N shown in Fig. 25 taken along line DD.

[0197] As shown in Fig. 25, the through-hole 31H is formed in an area on the upper surface of the optical function unit 30E where the convex portion 32 is not formed, i.e., an area where the upper surface of the base portion 31B is exposed. Moreover, as shown in Fig. 26, the through-hole 31H penetrates from the upper surface to the lower surface of the base portion 31B. The through-hole 31H is formed with a diameter of, for example, about φ50 μm.

[0198] In the first embodiment and the first to tenth modifications, the low refractive index portion 40 is air, and is a space sealed by the wavelength conversion member 22 , the optical function portion 30E, and the light reflecting member 50 .

[0199] In this case, heat generated when the light-emitting device is operating causes the air to expand, increasing the internal pressure within the low refractive index section 40, and the resulting stress may cause distortion of the optical function section 30E, resulting in a decrease in narrow-angle performance, or even cause the optical function section 30E to fall off.

[0200] By providing the through-hole 31H in the base 31B of the optical function part 30E, even if the air in the low refractive index part 40 expands due to heat generated when the light emitting device 1N is driven, the expanded air is released to the outside through the through-hole 31H. Therefore, the light emitting device 1N can prevent a decrease in narrow-angle performance due to distortion of the optical function part 30E or detachment of the optical function part 30E without an increase in internal pressure of the low refractive index part 40 even when driven.

[0201] (Modification 12) As in a light emitting device 1P according to Modification 12 shown in FIG. 27, the low refractive index portion 40A may be filled with a substance other than air.

[0202] In Example 1 and Variations 1 to 11, the case was described in which the low refractive index portion 40 was air with a refractive index n = 1.0, the optical function portion 30 was silicone resin with a refractive index n = 1.4, and the refractive index difference between the low refractive index portion 40 and the optical function portion 30 was approximately 0.4.

[0203] The low refractive index portion 40A is made of, for example, a silicone resin in which porous silica particles or hollow silica particles are dispersed as a filler, and has a refractive index n of about 1.1 to 1.3.

[0204] In this case, the optical function section 30 can be made of a high refractive index resin material with a refractive index n of about 1.5 to 1.7, or a high refractive index glass material with a refractive index n of about 1.7 to 1.9.

[0205] By selecting an appropriate material and adjusting the refractive index difference between the low refractive index section 40A and the optical function section 30, the refraction angle at the interface between the low refractive index section 40A and the optical function section 30 can be adjusted, making it possible to adjust the narrow-angle performance, i.e., directional characteristics, of the emitted light from the light-emitting device 1P.

[0206] In other words, if a light-emitting device requires sharper directional characteristics (large proportion of narrow-angle components), the refractive index difference between the low refractive index section 40A and the optical function section 30 should be increased, and if a light-emitting device requires less directional characteristics (small proportion of narrow-angle components), the refractive index difference between the low refractive index section 40A and the optical function section 30 should be decreased.

[0207] Furthermore, by using a resin material for the low refractive index portion 40A, thermal expansion can be suppressed compared to air when heat is generated during operation of the light emitting device 1P, and it is possible to suppress a decrease in narrow-angle performance due to distortion of the optical function portion 30 or the detachment of the optical function portion 30.

[0208] (Modification 13) Furthermore, as in a light emitting device 1Q according to Modification 13 shown in FIG. 28, the spacer portions for forming the low refractive index portions 40 may be formed of another material.

[0209] In the light emitting device 1Q, a spacer portion 52 is provided to separate the upper surface 22S of the wavelength conversion member 22 and the lower surface of the base portion 31 of the optical function portion 30 by a predetermined distance.

[0210] The spacer portion 52 is made of, for example, titanium oxide (TiO ２ The spacer portion 52 is made of a thermosetting silicone resin that contains a high content of .) particles and has high viscosity before curing. The spacer portion 52 is, for example, drawn using a dispenser in an area along the periphery of the upper surface 22S of the wavelength conversion member 22. The spacer portion 52 is heated for a short time to a degree that the surface remains adhesive, resulting in a provisionally cured state. After that, the optical function portion 30 is placed on top of the spacer portion 52, and then heated to fully cure. As a result, the spacer portion 52 separates the upper surface 22S of the wavelength conversion member 22 from the lower surface of the base 31 of the optical function portion 30 by a predetermined distance and bonds the wavelength conversion member 22 and the optical function portion 30 together.

[0211] The light emitted from the region of the upper surface 22S of the wavelength conversion member 22 excluding the region where the spacer portion 52 is formed is incident on the lower surface of the base portion 31 of the optical function portion 30 via the low refractive index portion 40, as in the first embodiment. Therefore, the light emitting device 1Q can narrow the angle of the emitted light.

[0212] 28 , a coating layer RE such as a fluorine film having low affinity for resin materials may be formed on the upper surface 22S of the wavelength conversion member 22 except for the region where the spacer portion 52 is formed, and on the lower surface of the base 31 of the optical function unit 30 except for the region joined to the spacer portion 52. This makes it possible to prevent the precursor of the silicone resin contained in the spacer portion 52 from wetting and spreading over the upper surface 22S of the wavelength conversion member 22 and the lower surface of the base 31 of the optical function unit 30.

[0213] In addition, the spacer portion 52 may be formed by drawing in an area along the outer periphery of the upper surface 22S of the wavelength conversion member 22, or may be formed intermittently or in a dot-like manner at a position symmetrical to the center point of the upper surface 22S of the wavelength conversion member 22.

[0214] The spacer portion 52 may also include spherical particles as spacers that separate the upper surface 22S of the wavelength conversion member 22 and the lower surface of the base portion 31 of the optical function portion 30 by a predetermined distance.

[0215] (Modification 14) Furthermore, as in a light emitting device 1R according to Modification 14 shown in FIGS. 29 and 30, a light blocking film 61 that blocks light may be formed on part of the upper surface 22S of the wavelength conversion member 22.

[0216] Fig. 29 is a top view of a light emitting device 1R according to Modification 14. Fig. 30 is a cross-sectional view of the light emitting device 1R shown in Fig. 29 taken along line EE.

[0217] The light-shielding film 61 is, for example, a multilayer reflective film or a reflective film made of a metal film that reflects light traveling upward from inside the wavelength conversion member 22 .

[0218] In top view, the light-shielding film 61 has an opening 61O formed in the region directly below the center point of the convex portion 32. That is, light is emitted from the upper surface 22S of the wavelength conversion member 22 only through the opening 61O of the light-shielding film 61.

[0219] This makes it possible to prevent light incident from the area directly below one convex portion 32 on the underside of the base portion 31 of the optical function portion 30 from being incident on another adjacent convex portion 32 inside the base portion 31. Therefore, the light emitting device 1R can emit light with only narrow-angle components, and it becomes possible to increase the proportion of narrow-angle components in the emitted light of the light emitting device 1R.

[0220] Note that light that travels upward within wavelength conversion member 22 and is reflected downward by light-shielding film 61 is likely to be reflected upward again by the reflective film formed on the lower surface of semiconductor light-emitting element 21 and to be emitted from opening 61O of light-shielding film 61. Therefore, by forming light-shielding film 61 having opening 61O on upper surface 22S of wavelength conversion member 22, the luminous flux of light emitted from opening 61O can be increased, and the luminous flux of the narrow-angle component of light emitted from light emitting device 1R can be increased.

[0221] (Modification 15) Furthermore, as in a light emitting device 1S according to Modification 15 shown in FIG. 31, an optical multilayer film 62 may be formed on an upper surface 22S of a wavelength conversion member 22.

[0222] The optical multilayer film 62 controls the transmittance of each wavelength in the light emitted from the upper surface 22S of the wavelength conversion member 22, thereby suppressing changes in chromaticity due to changes in the emission angle and improving the uniformity of chromaticity. The optical multilayer film 62 can be formed by stacking multiple optical layers with different refractive indices. For example, the material for the low refractive index layer can be a transparent dielectric with a refractive index of 1.6 or less, such as SiO ２ , MgF ２ The high refractive index layer is made of TiO having a refractive index of 1.6 or more. ２ , Al ２ O ３ , ZrO ２ , HfO ２ , Nb ２ O ５ ,BaTi ２O ５ , Ta ２ O ５ etc. are used.

[0223] (Modification 16) Furthermore, as in a light emitting device 1T according to Modification 16 shown in FIG. 32, the lower surface of the base 31C of the optical function part 30F may be formed in a downwardly convex shape.

[0224] By forming the lower surface of the base 31C of the optical function unit 30F to be convex downward, the lens effect of the lower surface of the base 31C causes the light emitted from the upper surface 22S of the wavelength conversion member 22 to be focused inward according to Snell's law, thereby increasing the brightness near the center of the light emission surface of the light emitting device 1T.

[0225] 33 shows a light emitting device 1U according to a seventeenth modification, in which the lower surface of the base 31D of the optical function unit 30G may be formed in an upwardly convex shape, thereby making it possible to suppress the difference in brightness within the light emitting surface when observed from directly above the light emitting device 1U.

[0226] (Modification 18) Furthermore, as in a light-emitting device 1V according to Modification 18 shown in FIGS. 34 and 35, a protrusion 36 formed in a downwardly convex shape may be provided on the lower surface of the base 31E of the optical function part 30H.

[0227] Fig. 34 is a top view of a light emitting device 1V according to Modification 18. Fig. 35 is a cross-sectional view of the light emitting device 1V shown in Fig. 34 taken along line FF.

[0228] The protrusion 36 is a protrusion formed integrally with the base 31E. For example, as shown in Fig. 34 , the protrusion 36 is formed on the lower surface of the base 31E immediately below the region where the convex portion 32 is not formed on the upper surface of the optical function unit 30 in top view, i.e., the region where the upper surface of the base 31E is exposed.

[0229] The height of the protrusion 36 is, for example, smaller than the thickness of the low refractive index portion 40 and is formed at a height that does not contact the coating layer RE.

[0230] By forming a protrusion 36 on the underside of the base 31E of the optical function part 30H, when the base 31E of the optical function part 30H is distorted into a downward convex shape due to heat generated when the light emitting device 1V is in operation, the protrusion 36 functions as a stopper to ensure the thickness of the low refractive index part 40.

[0231] This allows the light emitting device 1V to ensure the thickness of the low refractive index section 40 even when driven, and to suppress a decrease in the narrow angle performance of the emitted light.

[0232] The protrusion 36 may be formed in a columnar, conical or frustum shape from the lower surface of the base 31E.

[0233] (Variant 19) Furthermore, as in the light-emitting device 1W according to variant 19 shown in FIG. 36, an extension portion EX extending outward from the outer surface of the spacer portion 33A of the optical function portion 30I may be formed in the lower end region of the outer surface of the spacer portion 33A.

[0234] 36, the formation of the extension portion EX increases the area of ​​the lower surface of the spacer portion 33A, thereby increasing the bonding area with the light reflecting member 50. This makes it possible to improve the bonding strength of the optical function portion 30I.

[0235] Furthermore, by forming the light reflecting member 50 on the outer surface of the extension portion EX, the bonding strength of the optical function portion 30 can be further improved.

[0236] Note that the light reflecting member 50 does not have to be formed up to the outer surface of the extension portion EX, since this increases the bonding area of ​​the lower surface of the spacer portion 33A of the optical function portion 30. On the other hand, similar to what has been described in the first embodiment, the light reflecting member 50 may be formed so as to extend up to the upper surface of the extension portion EX and cover the lower end region of the outer surface of the base portion 31.

[0237] In addition, the lower surface of the spacer portion 33A may be arranged on the upper surface 22S of the wavelength conversion member 22 or the upper surface 21S of the semiconductor light-emitting element 21, and the extension portion EX may be made to protrude outward from the upper surface 22S of the wavelength conversion member 22 or the upper surface 21S of the semiconductor light-emitting element 21 and be joined to the light-reflecting member 50.

[0238] (Modification 20) Furthermore, as in a light emitting device 1X according to modification 20 shown in FIG. 37, the upper surface of the semiconductor light emitting element 21 and the lower surface of the wavelength conversion member 22 may be different in size.

[0239] If the size of the bottom surface of the wavelength conversion member 22 is larger than the size of the top surface of the semiconductor light-emitting element 21, a light-guiding section 70 made of optically transparent resin may be formed, extending from the side surface of the semiconductor light-emitting element 21 to the outer edge of the bottom surface of the wavelength conversion member 22.

[0240] By forming the light-guiding section 70, light emitted from the side surface of the semiconductor light-emitting element 21 and entering the light-guiding section 70 can be reflected by the light-reflecting member 50 and guided upward to the lower surface of the wavelength conversion member 22.

[0241] Therefore, it is possible to improve the light extraction efficiency of the light emitting device 1X.

[0242] (Variant 21) Furthermore, when the size of the lower surface of the wavelength conversion member 22 is smaller than the upper surface of the semiconductor light emitting element 21, as in the light emitting device 1Y according to variant 21 shown in FIG. 38 , a light guiding section 70 made of a light-transmitting resin may be formed, extending from the outer edge of the upper surface of the semiconductor light emitting element 21 to the lower end of the inclined surface of the side surface of the wavelength conversion member 22.

[0243] By forming the light guiding section 70, light that is emitted from the side surface of the wavelength conversion member 22 and enters the light guiding section 70 can be reflected by the light reflecting member 50 and re-enter from the side surface of the wavelength conversion member 22.

[0244] Therefore, it is possible to improve the light extraction efficiency of the light emitting device 1Y. (Variant 22) As for the light emitting device 1Z according to variant 22 shown in Figure 39, when a material other than air is used as the low refractive index portion 40A, as in the light emitting device 1P according to variant 12 described above, the low refractive index portion 40A can also be formed on the upper surface 22S of the wavelength conversion member 22.

[0245] The low refractive index portion 40A can be made of a light-transmitting resin having a refractive index n of about 1.05 to 1.3, which is made of a silicone resin in which porous silica particles or hollow silica particles are dispersed as a filler.

[0246] In this case, the optical function portion 30 can be made of a high refractive index resin material with a refractive index n of about 1.4 to 1.7, or a high refractive index glass material with a refractive index n of about 1.7 to 1.9.

[0247] As shown in FIG. 40( a ), the optical function section 30 in the light emitting device 1 Z may be configured without the spacer section 33 .

[0248] The low refractive index portion 40A and the optical function portion 30 can be bonded together by an appropriate bonding method.

[0249] For example, as shown in FIG. 40(a), bonding may be performed using a light-transmitting adhesive sheet (not shown), or direct bonding may be performed.

[0250] Alternatively, the low refractive index portion 40A may be formed in advance on the bottom surface of the optical function portion 30 and then bonded by an appropriate method onto the upper surface 22S of the wavelength conversion member 22. In this case, the low refractive index portion 40A may be formed over the entire bottom surface of the optical function portion 30 and formed to have approximately the same width as the optical function portion 30. Alternatively, the low refractive index portion 40A may be formed on the bottom surface of the optical function portion 30 in a position facing the upper surface 22S, in accordance with the width of the upper surface 22S of the wavelength conversion member 22.

[0251] 40(b), for example, a liquid adhesive AD can be applied to bond the optical function unit 30 onto the low refractive index unit 40A. When applying the adhesive AD, the adhesive AD may be applied onto the upper surface of the light reflecting member 50.

[0252] (Verification of the number of convex portions arranged and the thickness of the low refractive index portion) In the above-mentioned Example 1, as explained in Figure 6, the convex portions 32 of the optical function portion 30 are arranged in a matrix of 3 rows and 3 columns, totaling 9 convex portions.

[0253] Figure 41 shows the simulation results of the thickness T2 of the low refractive index section 40 and the luminous flux ratio of the narrow-angle component of light emitted from the light-emitting device 1 when the convex sections 32 of the optical function section 30 are arranged in 1 row and 1 column, 2 rows and 2 columns, 3 rows and 3 columns, 5 rows and 5 columns, and 10 rows and 10 columns.

[0254] In Figure 41, similar to the arrangement of the convex portions 32 described in Figure 9, the convex portions 32 are arranged in each of the sections obtained by dividing the upper surface of the base 31 of the optical function unit 30 into equal sections in the X and Y directions, from 1 row and 1 column (1 section in total) to 10 rows and 10 columns (100 sections in total), and each of the convex portions 32 is formed in the shape of a hemisphere with a radius R1 centered at the center point P1 of the respective section.

[0255] Furthermore, similar to Example 1 above, the simulation was performed assuming that the light-emitting section 20 was a square with a side length D1 of 1.0 mm on the light-emitting surface of the semiconductor light-emitting element 21 and a side length D2 of 0.85 mm on the upper surface 22S of the wavelength conversion member 22.

[0256] The simulation was performed assuming that the thickness T1 of the base 31 of the optical function portion 30 was 5% of the length of one side of the upper surface of the base 31, that is, the thickness T1 of the base 31 was 50 μm.

[0257] The horizontal axis in Fig. 41 indicates the ratio of the thickness T2 of the low refractive index portion 40 to the length D3 of one side of the upper surface of the base 31 of the optical function portion 30. Note that a ratio of 0% of the thickness T2 of the low refractive index portion 40 on the horizontal axis in Fig. 41 means that the low refractive index portion 40 is not present in the light emitting device 1, that is, the spacer portion 33 is not provided, and the lower surface of the base 31 is in contact with the upper surface 22S of the wavelength conversion member 22.

[0258] The vertical axis of Fig. 41 shows the luminous flux ratio within a narrow angle range (±30°) when the ratio of the thickness T2 of the low refractive index portion 40 is changed. Note that, on the vertical axis of Fig. 41, the luminous flux amount within the narrow angle range in a light emitting device that does not include an optical function portion 30 and that emits light with directional characteristics of ideal Lambertian orientation from the top surface of the wavelength conversion member is set to 100%. In the light emitting device that emits light with directional characteristics of ideal Lambertian orientation, the top surface of the wavelength conversion member has a square shape with sides of 1.0 mm.

[0259] Figure 41 shows the simulation results when the convex portions 32 are arranged in one row and one column, the dotted line in two rows and two columns, the dashed line in three rows and three columns, the two-dotted line in five rows and five columns, and the dotted line in ten rows and ten columns.

[0260] As shown in FIG. 41, by providing a low refractive index portion 40 between the upper surface 22S of the wavelength conversion member 22 and the lower surface of the base portion 31, the amount of light flux within the narrow angle range increases.

[0261] It was also found that a good amount of light flux could be obtained when the number of convex portions 32 arranged was 2 rows and 2 columns, or 3 rows and 3 columns.

[0262] Specifically, when the number of convex portions 32 arranged is 3 rows and 3 columns, similar to that of the light-emitting device of Example 1, the narrow-angle luminous flux ratio is 130% or more when the ratio of the thickness T2 of the low refractive index portion 40 to the length of one side of the upper surface of the base 31 of the optical function portion 30 is in the range of 0.6% or more and 9.4% or less (see Figures 6 and 41).

[0263] Furthermore, when the number of convex portions 32 arranged is 2 rows and 2 columns, the narrow-angle luminous flux ratio is 130% or more when the ratio of the thickness T2 of the low refractive index portion 40 to the length of one side of the upper surface of the base 31 of the optical function portion 30 is in the range of 0.1% or more and 17.0% or less.

[0264] From the simulation results of Figure 41, it was found that when the number of convex portions 32 arranged was changed, an arrangement of four (two rows and two columns) provided the largest allowable range of the thickness T2 of the low refractive index portion 40 for the narrow-angle component of the light emitted from the light-emitting device 1.

[0265] Fig. 42 is a top view of the light emitting device 2 according to Example 2. Fig. 43 is a cross-sectional view of the light emitting device 2 shown in Fig. 42 taken along line F-F. In Fig. 43, D1 indicates the length of one side of the top surface shape of the semiconductor light emitting element 21. This also roughly coincides with one side of the outline of the base 81 of the optical function unit 80. D2 indicates the length of one side of the top surface of the wavelength converting unit. D3 indicates the length of one side of the surface of the incident surface to the optical function unit 80 that faces the top surface 22S of the wavelength converting unit.

[0266] In the second embodiment, the substrate 10, the light emitting portion 20, and the light reflecting member 50 have the same configuration as in the first embodiment, and therefore a description thereof will be omitted.

[0267] Example 2 differs from Example 1 in that the convex portion 82 formed on the base 81 of the optical function portion 80 has a flat side surface 82S that extends in a direction along the side surface of the base 81, i.e., in a direction perpendicular to the top surface of the base 81, in the region along the outer edge of each base 81.

[0268] Furthermore, Example 2 differs from Example 1 in that the convex portions 82 of the optical function portion 80 are formed in an arrangement of two rows and two columns based on the simulation results shown in FIG.

[0269] When the top surface of the base 81 is divided into equal sections in two rows and two columns in the XY direction, the convex portion 82 is formed in a hemispherical shape with a radius R3 from the center point P3 of each section.

[0270] The convex portions 82 are formed with a radius R3 that exceeds half the length of one side of the above-mentioned section. That is, in top view, each of the convex portions 82 is bounded by a straight line portion with the adjacent convex portions 82 being arc-shaped in other portions. In other words, in top view, the convex portions 82 have a shape that combines arcs and straight lines.

[0271] In addition, in the region along the outer edge of the base 81 of the protrusion 82, a flat side surface 82S is formed in the direction along the side surface of the base 81.

[0272] In other words, the convex portions 82 have a shape obtained by cutting the tangent surfaces and flat side surfaces 82S of the overlapping portions of adjacent convex portions 82 from a hemisphere having a radius R3.

[0273] As shown in Figure 43, the protrusions 82 consist of first portions 82A having a rectangular cross-sectional shape in a cross section passing through the center points P3 of each of the adjacent protrusions 82, and spherical crown-shaped second portions 82B having an arcuate cross-sectional shape in a cross section passing through the center points P3, located on each of the first portions 82A, and formed continuously with each of the first portions 82A.

[0274] The first portion 82A is formed so that the upper end of the flat side surface 82S and the upper end of the tangent plane to the adjacent protrusions 82 are at the same height from the base 81. That is, the first portion 82A has a rectangular cross-sectional shape in a cross section passing through the center point P3 of each section of the upper surface of the base 81 (cross section taken along line F-F in FIG. 42). In addition, the distance from the center point P3 to the upper end of the flat side surface 82S and the upper end of the tangent plane to the adjacent protrusions 82 are each the same as the radius R3.

[0275] The second portion 82B is formed continuously with the first portion 82A in a spherical crown shape with a radius R3 from the end of the upper surface of the first portion 82A.

[0276] In a cross section passing through the center point P3, the angle θ is the angle between a line connecting the upper end of the flat side surface 82S to the center point P3 and a line connecting the center point P3 to the upper ends of the tangent planes of adjacent convex portions 82. Note that the lines connecting the center point P3 of the second portion 82B to both ends of the ends of the upper surface of the first portion 82A each make the same angle with the center line O, which is a line that passes through the center point P3 and is perpendicular to the upper surface of the base 81, i.e., each angle is θ / 2.

[0277] The angle θ of the second portion 82B is the aperture angle of the second portion 82B as a lens when the center point P3 is a point light source.

[0278] In other words, in a cross section passing through the center points P3 of the adjacent convex portions 82, the surface of the second portion 82B has a spherical crown-shaped curved surface, the polar angle of which is θ / 2.

[0279] The angle θ and the height of the first portion 82A from the upper surface of the base 81 are determined by the radius R3 of the convex portion 82.

[0280] Fig. 44 is a diagram schematically illustrating the case where the angle θ is changed for the protrusion 82 in Example 2. Fig. 44 illustrates one protrusion 82, and the length of one protrusion in a cross section passing through the center point P3 (cross section taken along line F-F in Fig. 42) is D1 / 2.

[0281] 44 , when the radius R3 of the convex portion 82 is small, the height of the first portion 82A from the upper surface of the base 81 is small, and the angle θ is large. Conversely, when the radius R3 of the convex portion 82 is large, the height of the first portion 82A from the upper surface of the base 81 is large, and the angle θ is small.

[0282] (Verification of the opening angle of the second part) Figure 45 shows the simulation results of the luminous flux ratio of the narrow-angle component of light emitted from the light-emitting device 2 by changing the angle θ, which is the opening angle of the second part 82B of the convex portion 82 of the optical function part 80.

[0283] In Figure 45, the simulation was performed with the light-emitting section 20 being a square with a side length D1 of 1.0 mm on the light-emitting surface of the semiconductor light-emitting element 21, and the upper surface 22S of the wavelength conversion member 22 being a square with a side length D2 of 0.85 mm, as in Example 1 above.

[0284] The simulation was performed on the optical function unit 80 with the base 81 having an outer shape of a 1.0 mm square, as in Example 1. The thickness T1 of the base 81 of the optical function unit 80 and the height T2 of the spacer unit 83 of the optical function unit 80 were each set to 5% of the length of one side of the top surface of the base 81. That is, the simulation was performed on the basis that the thickness T1 of the base 81 of the optical function unit 80 and the thickness T2 of the spacer unit 83 of the optical function unit 80 were each set to 50 μm.

[0285] 45 indicates the angle θ, which is the aperture angle of the second portion 82B of the optical function section 80. In this simulation, the angle θ was varied from 50° to 180°.

[0286] As described above, as the angle θ increases, the radius R3 of the convex portion 82 decreases.

[0287] When the angle θ on the horizontal axis in FIG. 45 is 180°, the convex portion 82 is formed only of hemispherical convex portions.

[0288] The vertical axis of Fig. 45 shows the luminous flux ratio within a narrow angle range (±30°) when the angle θ of the second portion 82B is changed. Note that, on the vertical axis of Fig. 45, the luminous flux amount within a narrow angle in a light emitting device that does not include an optical function unit 80 and that emits light with directional characteristics of ideal Lambertian orientation from the top surface of the wavelength conversion member is set to 100%. In the light emitting device that emits light with directional characteristics of ideal Lambertian orientation, the top surface of the wavelength conversion member has a square shape with sides of 1.0 mm.

[0289] 45 , when the angle θ of the second portion 82B of the optical function unit 80 is in the range of 52° or more and 100° or less, the luminous flux ratio within the narrow angle exceeds 100%. When the angle θ of the second portion 82B of the optical function unit 80 is in the range of 80° or more and 180° or less, the luminous flux ratio within the narrow angle is 130% or more. Furthermore, it was found that the luminous flux ratio within the narrow angle is highest when the angle θ of the second portion 82B of the optical function unit 80 is in the range of 95° or more and 150° or less. It was also found that the angle θ at which the luminous flux ratio within the narrow angle reaches its peak is 119°.

[0290] 43 and 44, the surfaces of the second portions 82B of adjacent convex portions 82 have a spherical crown-like curved surface. In a cross section passing through the center point P3 (cross section taken along line F-F in FIG. 42), the angle between the line from the center P3 of the sphere to the apex of the spherical crown and the edge of the spherical crown curved surface (the point tangent to the edge of the upper surface of the first portion 82A), i.e., the polar angle, is θ / 2.

[0291] That is, the surface of the second portion 82B has a spherical crown-like curve, and when the polar angle (θ / 2) is between 26° and 90°, a high amount of luminous flux within the narrow angle can be obtained. Furthermore, when the polar angle is between 40° and 90°, an even higher amount of luminous flux can be obtained, and when the polar angle is between 47.5° and 75°, an even higher amount of luminous flux can be obtained.

[0292] (Verification of thickness of base of optical function part) Figure 46 is a diagram showing the simulation results of the luminous flux ratio of the narrow-angle component of light emitted from the light emitting device 2 when the thickness T1 of the base 81 of the optical function part 80 is changed.

[0293] 46, the simulation was performed based on the simulation results shown in Fig. 45, with the angle θ of the second portion 82B of the optical function unit 80 set to 119°. The other structures of the light-emitting device 2 are similar to those described in Fig. 45.

[0294] The horizontal axis in FIG. 46 represents the ratio of the thickness T1 of the base 81 to the length of one side of the top surface of the base 81 of the optical function part 80.

[0295] In FIG. 46, a simulation was performed by varying the ratio of the thickness T1 of the base 81 of the optical function portion 80 to the length of one side of the top surface of the base 81 from 2% to 40%.

[0296] The simulation was performed with the thickness of the spacer portion 83 of the optical function portion 80, that is, the ratio of the thickness to the thickness T2 of the low refractive index portion 40, set to 5%.

[0297] The vertical axis of Fig. 46 shows the luminous flux ratio within a narrow angle range (±30°) when the ratio of the thickness T1 of the base 81 is changed. As in Fig. 45, the vertical axis of Fig. 46 sets the luminous flux amount within a narrow angle to 100% in a light emitting device that does not include an optical function unit 80 and that emits light with ideal Lambertian orientation directional characteristics from the top surface of the wavelength conversion member. In addition, in the light emitting device that emits light with ideal Lambertian orientation directional characteristics, the top surface of the wavelength conversion member has a square shape with sides of 1.0 mm.

[0298] As shown in FIG. 46, in the simulation range where the ratio of the thickness T1 of the base portion 81 of the optical function portion 80 is in the range of 2% to 33%, the narrow angle luminous flux ratio is 130% or more.

[0299] Furthermore, the narrow-angle luminous flux ratio was 140% or more when the thickness T1 of the base 81 of the optical function part 80 was in the range of 2% or more and 15% or less. It was found that setting the thickness T1 of the base 81 of the optical function part 80 in the range of 2% or more and 10% or less had a significant effect on the narrow-angle luminous flux ratio.

[0300] Within the range of the simulation, it was found that a ratio of the thickness T1 of the base 81 of 5% was most effective for the narrow-angle luminous flux ratio.

[0301] (Function of the Convex Portion of the Optical Function Section of the Second Embodiment) The function of the convex portion 82 of the light emitting device 2 of the second embodiment will be described with reference to FIGS.

[0302] 47 and 48 are enlarged cross-sectional views of the wavelength conversion member 22 and the optical function parts 30 and 80 in the cross sections of Fig. 2 and Fig. 43. Note that in order to facilitate explanation of the optical paths of the emitted light LM4, LM5, LM6, LM7, LM8, and LM9 from the light emitting devices 1 and 2, the coating layer RE is not shown and the optical function parts 30 and 80 are not hatched.

[0303] Figure 47 shows the optical paths of emitted light LM4, LM5, and LM6, which are part of the light emitted from the end of the upper surface 22S of the wavelength conversion member 22 in the light emitting device 1 of Example 1.

[0304] Figure 48 shows the optical paths of emitted light LM7, LM8, and LM9, which are part of the light emitted from the end of the upper surface 22S of the wavelength conversion member 22 in the light emitting device 2 of Example 2.

[0305] 47 and 48, the case will be described where the emitted lights LM4, LM5, LM6 and the emitted lights LM7, LM8, LM9 are each emitted outward from the end of the top surface 22S at the same angle. That is, in Figures 47 and 48, the emitted lights LM4 and LM7 shown by solid lines, the emitted lights LM5 and LM8 shown by dashed lines, and the emitted lights LM6 and LM9 shown by dashed lines are each emitted from the end of the top surface 22S at the same angle.

[0306] Furthermore, the case will be described in which the emission angles of the emitted lights LM4, LM5, LM6 and the emitted lights LM7, LM8, LM9 approach the optical axis direction (lens axis direction) in the order of the emitted lights LM4, LM5, LM6 and the emitted lights LM7, LM8, LM9, respectively.

[0307] 47, the convex portion 32 is a hemispherical lens. Therefore, particularly in the outer end region of the convex portion 32 when viewed from above, the angle of incidence of light such as output light LM4 and LM5, which has a large inclination angle from the optical axis direction, with respect to the surface (tangential plane) of the convex portion 32, i.e., the angle with respect to the tangent at the point of incidence on the surface of the convex portion 32, tends to be large.

[0308] As a result, the emitted light LM4 and LM5 repeatedly undergo total reflection on the surface of the convex portion 32, becoming return light to the wavelength conversion member 22, and some of this light may not be emitted from the convex portion 32 or may not be emitted within a narrow angle range.

[0309] Therefore, of the emitted light LM4, LM5, and LM6 emitted outward from the end of the upper surface 22S shown in Figure 47, only the emitted light LM6, whose emission angle is relatively close to the optical axis direction, is emitted outward from the surface of the convex portion 32 into the air.

[0310] In contrast, as shown in FIG. 48, in the light emitting device 2 of Example 2, the flat side surface 82S and the surface of the second portion 82B allow emitted light to be extracted from the optical function portion 80 more efficiently than in Example 1.

[0311] Specifically, light such as emitted light LM7, which has the largest inclination angle from the optical axis direction, is totally reflected on the surface of the flat side surface 82S, which is the side surface of the first portion 82A, and is emitted outward into the air from the surface of the second portion 82B.

[0312] Furthermore, in the second portion 82B, the radius R3 of the convex portion 82 is larger than the radius R1 of the convex portion 32 of Example 1, that is, the curvature of the surface of the second portion 82B is larger than that of the convex portion 32 of Example 1. Therefore, the angle of incidence of light such as the emitted light LM8, which has the second largest inclination angle from the optical axis after the emitted light LM7, with respect to the surface (tangential plane) of the second portion 82B can be made small, and total reflection of the emitted light LM8 can be suppressed.

[0313] Therefore, the emitted light LM8 is refracted at a narrow angle on the surface of the second portion 82B and emitted outward from the second portion 82B into the air.

[0314] In this way, in the light emitting device 2 of the second embodiment, light can be extracted from the optical function portion 80 more efficiently.

[0315] Therefore, according to the light emitting device 2 of the second embodiment, it is possible to increase the luminous flux of the light emitted from the light emitting device 2.

[0316] According to the inventors, it has been verified that the light emitting device 2 of Example 2 has an improved luminous flux of the narrow-angle component by approximately 3.5% compared to the light emitting device 1 of Example 1.

[0317] In the light-emitting device 2 of Example 2 described above, a total of four convex portions 82 are arranged in two rows and two columns, but based on the simulation results of Figure 41, the convex portions 82 may also be arranged in a total of nine convex portions 82 in three rows and three columns.

[0318] Furthermore, in the light-emitting device 2 of the above-mentioned Example 2, as shown in Figure 42, we have described a case where, in a cross section passing through the center point P3 of each of adjacent convex portions 82, the angle θ, which is the opening angle of the second part 82B of the convex portion 82, is within the range described in Figure 45, but the shape of the convex portion 82 is not limited to this.

[0319] For example, when viewed from above, in a cross section passing through the center point P3 of each of the convex portions 82 arranged at diagonal positions on the upper surface of the base 81, the convex portions 82 arranged at diagonal positions on the upper surface of the base 81 may overlap each other as shown in Figure 43, and each may have a flat side surface 82S.

[0320] That is, in a cross section passing through the center point P3 of each of the plurality of protrusions 82, the angle θ, which is the opening angle of the second portion 82B, may be within the range explained in FIG.

[0321] In the light emitting devices of Examples 1 and 2 described above, for example, a coating layer RE made of a fluororesin having the property of repelling uncured resin has been described as being formed, but the coating layer RE may be provided arbitrarily and may not be necessary. Furthermore, the coating layer RE may be a layer having a function other than the function of repelling uncured resin. For example, a dielectric film or a dielectric multilayer film may be formed that has the function of suppressing reflection of light incident on the upper surface of the wavelength conversion member.

[0322] The configurations of the various parts of the examples and modifications in this description can be combined as appropriate. For example, in any of the examples and modifications, the radius and number of the multiple convex portions can be changed as appropriate, and an additional structure of the second convex portion 34 and a cylindrical lens-shaped structure such as the convex portion 35 can also be incorporated.

[0323] Furthermore, for example, in any of the embodiments and modifications, a structure for forming the light guide section 70 and a structure for providing the light-transmitting member 25 can be incorporated.

[0324] Furthermore, for example, in any of the embodiments and modified examples, the size relationship and positional relationship between the outer shape of the optical function part, the outer shape of the wavelength conversion member 22, and the outer shape of the semiconductor light-emitting element can be adjusted so that the convex portion arranged on the outermost periphery of the optical function part 30 when viewed from above overlaps with the outer edge of the upper surface of the light-emitting part 20, or within a range equivalent to overlapping.

[0325] Furthermore, for example, in any of the embodiments and modified examples, the arrangement of the light-reflecting member 50 can be changed as appropriate, and a structure can be incorporated that covers the inner surface of the recess of the substrate 10, the outer surface of the spacer portion of the optical function portion, and part of the lower end region of the outer surface of the base of the optical function portion.

[0326] Furthermore, for example, in any of the embodiments and modifications, it is also possible to incorporate a structure, as in the light emitting device 1I of Modification 6, in which the upper end of the side surface of the semiconductor light emitting element 21 or the upper end of the side surface of the wavelength conversion member 22 is covered with a light guiding section 70 made of a light-transmitting resin, and the light reflecting member 50 is formed on the upper surface of the light guiding section 70. In this case, as in the explanation of Modification 7, it is preferable that the light reflecting member 50 is formed so as to cover the outer surface of the spacer section 33 of the optical function section and a portion of the region from the lower end of the side surface of the base.

[0327] Furthermore, in any of the embodiments and modified examples, any combination is possible, such as a structure in which the low refractive index portion 40 is provided in a space formed in the wavelength conversion member 22, a structure in which a through hole 31H is provided in the base of the optical function portion, a structure in which a low refractive index material other than air is used as the low refractive index portion 40A to enable adjustment of the refractive index difference with the optical function portion, a structure in which a light-shielding film 61 having an opening is provided on the upper surface 22S of the wavelength conversion member 22, a structure in which an optical multilayer film 62 is provided on the upper surface 22S of the wavelength conversion member 22, a structure in which the shape of the base of the optical function portion is changed, and a structure in which an extension portion EX is provided on the outer surface of the spacer portion of the optical function portion.

[0328] As described above, the embodiments are not intended to limit the scope of the invention. Each embodiment and each modification can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These modifications are included in the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims.

[0329] REFERENCE SIGNS LIST 1, 2 Light emitting device 10 Substrate 20 Light emitting portion 21 Semiconductor light emitting element 22 Wavelength conversion member 25 Light-transmitting member 30, 80 Optical function portion 31, 81 Base portion 32, 34, 82 Convex portion 26, 33, 52, 83 Spacer portion 36 Protrusion portion 40 Low refractive index portion 50 Light reflecting portion 61 Light-shielding film 62 Optical multilayer film 70 Light guide portion

Claims

1. A substrate; a light emitting section disposed on the substrate, the light emitting section including a semiconductor light emitting element including a light emitting layer, the light emitting section having an upper surface from which light emitted from the light emitting layer is emitted; an optical function unit made of a light-transmitting member and having a base portion continuously extending to cover the upper surface of the light-emitting unit and a plurality of convex portions formed on the base portion; a spacer portion that separates the upper surface of the light-emitting portion and the lower surface of the base, which face each other, by a predetermined distance to form a gap between the upper surface of the light-emitting portion and the lower surface of the base; a light reflecting portion made of a light-reflecting material and covering at least a part of a side surface of the light-emitting portion, a side surface of the spacer portion, or a side surface of the base portion; a low refractive index portion disposed in the gap and formed of a low refractive index material having a refractive index lower than that of the optical function portion, the semiconductor light emitting element has a light emitting region on an upper surface through which the emitted light from the light emitting layer is emitted upward; the light emitting section includes a wavelength converting member disposed on an upper surface of the semiconductor light emitting element and configured to convert the wavelength of a portion of the emitted light emitted from the light emitting region; a side surface of the wavelength conversion member is covered with the light reflecting portion, the base of the optical function unit has a rectangular outer shape in a top view, the plurality of protrusions are arranged in a matrix, The light emitting device is characterized in that the optical function portion is formed so that the wavelength conversion member is disposed immediately below all of the convex portions that are disposed on the outermost periphery among the plurality of convex portions.

2. The light-emitting device according to claim 1, characterized in that the spacer portion comprises a protrusion protruding downward from the lower surface of the base, a protrusion protruding upward from the upper surface of the light-emitting portion, or a member arranged between the upper surface of the light-emitting portion and the lower surface of the base.

3. The light emitting device according to claim 2 , wherein the spacer portion is formed along an outer edge of the lower surface of the base portion.

4. 2. The light emitting device according to claim 1, wherein the shape of the lower surface of the wavelength conversion member is substantially the same as the shape of the light emitting region on the upper surface of the semiconductor light emitting element.

5. The light emitting device according to claim 1 , wherein the wavelength converting member of the light emitting section has a narrowed portion with an inwardly inclined surface on a part of the side surface.

6. 2. The light emitting device according to claim 1, wherein the plurality of convex portions of the optical function portion have upwardly projecting hemispherical or aspherical surfaces.

7. 2. The light emitting device according to claim 1, wherein the outer edge of the optical function portion is, when viewed from above, approximately coincident with the outer edge of the upper surface of the wavelength conversion member, or is located outside the outer edge of the upper surface of the wavelength conversion member.

8. A substrate; a light emitting section disposed on the substrate, the light emitting section including a semiconductor light emitting element including a light emitting layer, the light emitting section having an upper surface from which light emitted from the light emitting layer is emitted; an optical function unit made of a light-transmitting member and having a base portion continuously extending to cover the upper surface of the light-emitting unit and a plurality of convex portions formed on the base portion; a spacer portion that separates the upper surface of the light-emitting portion and the lower surface of the base, which face each other, by a predetermined distance to form a gap between the upper surface of the light-emitting portion and the lower surface of the base; a light reflecting portion made of a light-reflecting material and covering at least a part of a side surface of the light-emitting portion, a side surface of the spacer portion, or a side surface of the base portion; a low refractive index portion disposed in the gap and formed of a low refractive index material having a refractive index lower than that of the optical function portion, the base of the optical function unit has a rectangular outer shape in a top view, A light emitting device, characterized in that the thickness of the low refractive index portion is in the range of 0.1% to 20% of the length of one side of the upper surface of the base of the optical function portion.

9. the base of the optical function unit has a rectangular outer shape in a top view, 2. The light emitting device according to claim 1, wherein the thickness of the low refractive index portion is in the range of 0.1% to 10% of the length of one side of the upper surface of the base of the optical function portion.

10. 2. The light emitting device according to claim 1, wherein the low refractive index portion is made of air that fills the gap.

11. A substrate; a light emitting section disposed on the substrate, the light emitting section including a semiconductor light emitting element including a light emitting layer, the light emitting section having an upper surface from which light emitted from the light emitting layer is emitted; an optical function unit made of a light-transmitting member and having a base portion continuously extending to cover the upper surface of the light-emitting unit and a plurality of convex portions formed on the base portion; a spacer portion that separates the upper surface of the light-emitting portion and the lower surface of the base, which face each other, by a predetermined distance to form a gap between the upper surface of the light-emitting portion and the lower surface of the base; a light reflecting portion made of a light-reflecting material and covering at least a part of a side surface of the light-emitting portion, a side surface of the spacer portion, or a side surface of the base portion; a low refractive index portion disposed in the gap and formed of a low refractive index material having a refractive index lower than that of the optical function portion, The light emitting device is characterized in that the low refractive index portion is made of a resin material containing porous silica or hollow silica filled in the voids.

12. A substrate; a light emitting section disposed on the substrate, the light emitting section including a semiconductor light emitting element including a light emitting layer, the light emitting section having an upper surface from which light emitted from the light emitting layer is emitted; an optical function unit made of a light-transmitting member and having a base portion continuously extending to cover the upper surface of the light-emitting unit and a plurality of convex portions formed on the base portion; a spacer portion that separates the upper surface of the light-emitting portion and the lower surface of the base, which face each other, by a predetermined distance to form a gap between the upper surface of the light-emitting portion and the lower surface of the base; a light reflecting portion made of a light-reflecting material and covering at least a part of a side surface of the light-emitting portion, a side surface of the spacer portion, or a side surface of the base portion; a low refractive index portion disposed in the gap and formed of a low refractive index material having a refractive index lower than that of the optical function portion, Among the plurality of convex portions, a convex portion arranged on the outer periphery of the optical function portion has a flat side surface on a side surface along the outer periphery, the flat side surface extending in a direction along the side surface of the base portion, the plurality of protrusions each have a first portion that intersects with the flat side surface and has a rectangular cross section perpendicular to the flat side surface, and a second portion that has a spherical crown-shaped curved surface formed on an upper surface of the first portion, A light emitting device characterized in that the polar angle of the spherical crown-shaped curved surface is 26° or more and 90° or less.