JP2005123588A - Light emitting diode luminous source and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting diode luminous source for improving a light extraction efficiency from a light emitting diode element and a phosphor, and for increasing a radiated luminous flux. <P>SOLUTION: The light emitting diode luminous source according to this invention includes at least one light emitting diode element 12 packaged on a principle plane of a substrate 11, and the phosphor for translating a light radiated from the light emitting diode element 12 to a light having a longer wavelength than the radiated light. The light emitting diode luminous source is provided with a light wavelength transformation portion 13 covering at least one part of the light emitting diode element 12. A side face of this light wavelength transformation portion 13 has at least one concave curved surface part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an LED light source that performs wavelength conversion with a fluorescent material on at least a part of emitted light from an LED element, and a method for manufacturing the LED light source.

  In recent years, white LED light sources have been actively studied. When an LED element is used as a light source for illumination, in order to obtain a white color suitable for illumination, the blue LED element is covered with a fluorescent material that glows yellow (for example, Patent Document 1). Thereby, a part of the emitted light from the LED can be wavelength-converted with the fluorescent material, and white light can be extracted as the synthesized light. Specifically, for example, a blue LED element using a gallium nitride (GaN) material is coated with a YAG fluorescent material. In the LED light source of this example, light emission with a wavelength of 450 nm is generated from the blue LED element, and the fluorescent material receiving this light emits yellow fluorescence (peak wavelength is about 550 nm). By mixing these lights, white light is provided.

The inventor of the present application has completed the invention of directly dissipating heat from the LED to the mounting substrate by mounting the LED element directly on the mounting substrate, and disclosed in Patent Document 2. A cross-sectional view of the LED illumination light source 300 described in Patent Document 2 is shown in FIG. In this LED illumination light source, the LED element 12 provided on the substrate 11 is covered with a cylindrical resin portion 60 containing a fluorescent substance. The cylindrical resin part 60 is further covered with a second resin part 61. The cylindrical resin portion 60 functions as a light wavelength conversion portion, and the light 62 is emitted from the second resin portion 61 to the outside.
Japanese Patent No. 2998696 JP 2004-172586 A

  As the inventors of the present application further studied, it was found that the luminous flux emitted from the LED light source changes greatly by changing the shape of the cylindrical resin part 60 containing the fluorescent material.

  The object of the present invention is to improve the efficiency of extracting light from the LED element and the fluorescent material by adjusting the shape of the light wavelength conversion portion made of the resin containing the fluorescent material, and to increase the luminous flux. It is to provide a light source.

  An LED light source according to the present invention includes at least one LED element mounted on a main surface of a substrate, and a fluorescent material that converts light emitted from the LED element into light having a wavelength longer than the wavelength of the light, An LED light source comprising: a light wavelength conversion unit that covers at least a part of the LED element, wherein a side surface of the light wavelength conversion unit has at least one concave curved surface portion.

  In a preferred embodiment, a translucent member that covers at least a part of the light wavelength conversion unit is provided.

  In a preferred embodiment, the light wavelength conversion unit includes a reflective surface separated from the side surface and a light transmissive member covering at least a part of the light wavelength conversion unit, and the refractive index of the light transmissive member is It is different from the refractive index of the light wavelength conversion unit.

  In a preferred embodiment, the refractive index of the translucent member is larger than the refractive index of the light wavelength conversion unit.

In a preferred embodiment, the translucent member is made of resin,
The translucent member fills a gap between the side surface of the light wavelength conversion unit and the reflection surface of the light reflection member.

  In a preferred embodiment, the translucent member functions as a lens.

  In a preferred embodiment, the light wavelength conversion part is formed of a resin containing the fluorescent material.

  In a preferred embodiment, the cross section of the light wavelength conversion unit cut so as to cross the recess on the side surface of the light wavelength conversion unit by a plane perpendicular to the main surface of the substrate has an outer shape including a curve corresponding to the recess. And a value R / t obtained by dividing the curvature radius R of the curve by the thickness t of the light wavelength conversion unit is in the range of 0.5 or more and 8.5 or less.

  In a preferred embodiment, a value d / t obtained by dividing the depth d of the concave portion on the side surface of the light wavelength conversion portion by the thickness t of the light wavelength conversion portion is in the range of 0.03 to 0.5. .

  In preferable embodiment, the depth d of the recessed part in the said side surface of the said optical wavelength conversion part exists in the range of 0.01 mm or more and 0.17 mm or less.

  In a preferred embodiment, the light wavelength conversion portion has a substantially cylindrical shape, and the substantially cylindrical side surface forms the concave curved surface portion.

  In a preferred embodiment, the light wavelength conversion section has a substantially truncated cone shape, and a side surface of the substantially truncated cone shape forms the concave curved surface portion.

  Another LED light source according to the present invention includes a plurality of LED elements arranged on a main surface of a substrate, a plurality of reflecting surfaces surrounding each side surface of the plurality of LED elements, and light emitted from the LED elements. A plurality of light wavelength conversion units each including a fluorescent material that converts light having a wavelength longer than the wavelength of the light, each covering a corresponding LED element, and a plurality of light transmissions each covering a corresponding light wavelength conversion unit A side surface of each light wavelength conversion unit has at least one concave curved surface portion, and the translucent member includes the side surface of the light wavelength conversion unit and the light reflection member. The gap with the reflective surface is filled.

  The printing plate of the present invention is a printing plate used for forming a resin pattern on a substrate, and has a top surface, a bottom surface, and at least one through hole connecting the top surface and the bottom surface. The inner wall surface of the through hole in the plate-like member forms a convex curved surface protruding toward the center of the through hole while at least the resin filled in the through hole is cured.

  In a preferred embodiment, the plate-like member is made of a material whose shape changes flexibly according to an external force.

  In a preferred embodiment, the plate-like member is formed from an elastic body.

  In a preferred embodiment, a plate that further contacts at least one of the upper surface and the lower surface of the plate-like member is further provided.

  The method of manufacturing an LED light source according to the present invention includes a step (A) of mounting at least one LED element on a main surface of a substrate, and converting light emitted from the LED element into light having a wavelength longer than the wavelength of the light. And a step (B) of forming on the substrate a light wavelength conversion part that includes a fluorescent material that covers at least a part of the LED element, wherein the step (B) includes the step (B), Forming at least one concave curved surface portion on a side surface of the optical wavelength conversion unit.

  In a preferred embodiment, the step (B) includes a step (b1) of forming an isolated pattern of the material constituting the light wavelength conversion unit on the substrate, and a side surface of the isolated pattern is deformed to form the concave curved surface portion. (B2).

  According to the LED light source of the present invention, since the side surface of the light wavelength conversion portion containing the fluorescent material has a concave curved surface portion, the light extraction efficiency from the LED element and the fluorescent material is improved, and the luminous flux is increased. .

  Hereinafter, embodiments of an LED light source according to the present invention will be described with reference to the drawings.

  First, refer to FIG. FIG. 1 shows a cross section of an LED light source 100 according to the first embodiment.

  The illustrated LED light source 100 includes a substrate (mounting substrate) 11, a blue LED element 12 mounted in a flip-chip state on the main surface (upper surface) of the substrate 11, and a light wavelength conversion unit 13 that covers the LED element 12. It has. In FIG. 1, for the sake of simplicity, one LED element 12 and one light wavelength conversion unit 13 that covers the entire LED element 12 are shown. It is preferable to include a plurality of LED elements 12 arranged in a two-dimensional array on the surface and a plurality of light wavelength conversion units 13 each covering the corresponding LED element 12. However, the LED light source of the present invention may have a single LED element and a light wavelength conversion unit on one substrate, and one light wavelength conversion unit 12 covers a plurality of LED elements. May be.

  The substrate 11 is provided with a wiring (not shown), and the LED element 12 is electrically connected to the wiring on the substrate 11 through an electrode pad or the like. Thereby, a current is supplied to the LED element 12 from a lighting circuit (not shown), and the LED element 12 emits light. The substrate 11 provided with wiring may be a multilayer wiring substrate. In the case where a plurality of LED elements 12 are mounted, the substrate 11 is preferably manufactured using a metal composite substrate having excellent heat dissipation.

The light wavelength conversion unit 13 is formed of a resin containing a fluorescent material that converts blue light emitted from the blue LED element 12 into yellow light. As such a fluorescent material, for example, (Y · Sm) ₃ (Al · Ga) ₅ O ₁₂ : Ce, (Y _0.39 Gd _0.57 Ce _0.03 Sm _0.01 ) ₃ Al ₅ O _{12 and the} like can be used. The resin constituting the light wavelength conversion part 13 contains, for example, a silicone resin part as a main component, and its refractive index n1 is about 1.4.

  As described above, in this embodiment, an LED element that emits blue light is used. However, the LED light source of the present invention is not limited to the case of using such an LED element, and has a peak wavelength in another band. An LED element may be used. In that case, it is necessary to appropriately change or adjust the type of the fluorescent substance contained in the light wavelength conversion unit. The type of fluorescent material is not limited to one, and a plurality of types of fluorescent materials may be mixed in one light wavelength conversion unit. Moreover, you may use a different kind of fluorescent material for every several LED element mounted on the same board | substrate. A plurality of types of LED elements having different peak wavelengths may be arranged on the same substrate.

  The main characteristic point of this embodiment is the shape of the side surface of the light wavelength conversion unit 13. This point will be described in detail later, and the other components shown in FIG. 1 will be described here.

  In the LED light source 100 of the present embodiment, a surface (reflecting surface) that receives light emitted from each LED element 12 and the light modulation conversion unit 13 and reflects the light so as to be deflected in a direction perpendicular to the main surface of the substrate. Is provided on the main surface of the substrate 11. The reflection plate 14 is preferably a metal plate having a plurality of openings, and the inner surface of each opening functions as a reflection surface. In FIG. 1, a part of the reflecting plate 14 is illustrated, and the reflecting surface of the reflecting plate 14 has a parabolic shape. The reflector 14 is made of, for example, aluminum (Al).

  A characteristic point in the present embodiment is that the reflection surface of the reflection plate 14 is separated from the side surface of the light wavelength conversion unit 13. The size of the gap formed between the reflection surface of the reflection plate 14 and the side surface of the light wavelength conversion unit 13 is, for example, in the range of 100 μm to 10 mm.

  The light wavelength conversion unit 13 is preferably covered with a translucent member 15 formed from a resin. “Translucent” means that light can be transmitted and does not need to be completely transparent. The translucent member 15 of this embodiment functions as a convex lens and is mainly composed of an epoxy resin. The refractive index n2 of the translucent member 15 is about 1.6 (n2> n1). The “gap” between the reflection surface of the reflection plate 14 and the side surface of the light wavelength conversion unit 13 is filled with a translucent member. For this reason, the light emitted from the inside of the LED element 12 or the light wavelength conversion unit 13 passes through the interface between the light wavelength conversion unit 13 and the translucent member 15 and then reaches the reflection surface of the reflection plate 14. And reflected.

  The structure shown in FIG. 1 is an axis object with respect to the straight line A, except for the LED element 12. The LED element 12 typically has a rectangular parallelepiped shape. The LED element 12 has, for example, a thickness: about 60 μm and a top surface: 0.3 mm × 0.3 mm.

  In the present embodiment, since the LED element 12 is flip-chip mounted, a lead wire is unnecessary, and therefore, the formation of the light wavelength conversion unit 13 including a fluorescent material is facilitated. A preferred method of forming the light wavelength conversion unit 13 will be described later.

  Next, the operation of the LED light source 100 shown in FIG. 1 will be described.

  Part of the light emitted from the LED element 12 is absorbed by the fluorescent material of the light wavelength conversion unit 13 and is emitted from the fluorescent material as light having a longer wavelength (yellow light) (wavelength conversion). As a result, light (white light) in which blue light and yellow light radiated from the LED element 12 are mixed is emitted from the surface of the light wavelength conversion unit 13 to the outside. Since the white light is emitted to the outside of the LED light source 100 through the translucent member 15, the white light is condensed by the lens effect of the translucent member 15. As described above, part of the light emitted from the surface of the light wavelength conversion unit 13 is reflected by the reflecting plate 14 without being absorbed by the light wavelength conversion unit of the adjacent LED element (not shown). The light use efficiency (extraction efficiency) is improved as compared with the case where the reflector 14 is not provided.

  Hereinafter, the shape of the optical wavelength converter 13 will be described in detail with reference to FIG. FIG. 2 is an enlarged cross-sectional view showing the optical wavelength conversion unit 13 of FIG. 1 in detail. In FIG. 2, illustration of the translucent member 15 and the reflecting plate 14 is omitted for simplicity.

  As shown in FIG. 2, the light wavelength conversion unit 13 of the present embodiment has a substantially truncated cone shape having a bottom surface that is in contact with the main surface of the substrate 11. In the present embodiment, as shown in FIG. 2, the upper surface 131 (the surface of the first resin portion facing the substrate 11) of the light wavelength conversion unit 13 and the side surface 132 (the bottom surface in contact with the main surface of the substrate 11 and Both surfaces excluding the upper surface 131 have concave curved surfaces. Here, the “concave shape” means a shape in which the surface of the light wavelength conversion unit 13 is recessed in the direction in which the LED element 12 is positioned.

  FIG. 12 shows parameters that define the shape of the concave curved surface portion formed on the side surface of the light wavelength conversion unit. For simplicity, FIG. 12 schematically shows a cross section of a light wavelength conversion portion having a cylindrical shape, and its upper surface is also flat. In FIG. 12, the position of a virtual side surface (hereinafter referred to as “reference surface”) when it is assumed that there is no concave curved surface portion is indicated by a broken line H. In the present specification, a distance d between a point (the deepest point) farthest from the reference surface on the surface of the concave curved surface portion and the reference surface is referred to as a “depth of the concave curved surface portion”. The straight line that defines the distance (depth) d is a straight line (perpendicular) perpendicular to the reference plane H among straight lines passing through the deepest point.

  FIG. 12 also shows the curvature R of the concave curved surface portion and the height t of the light wavelength conversion unit. By these parameters d, R, and t, the shape characteristic of the concave curved surface portion can be expressed.

  Refer to FIG. 2 again. The optical wavelength converter 13 shown in FIG. 2 has an upper surface 131 with a diameter of about 0.7 mm and a bottom surface with a diameter of about 0.8 mm. The concave portions of the upper surface 131 and the side surface 132 each have a depth of 0.05 mm from the surface of the virtual truncated cone indicated by the dotted line in the drawing. Note that, as described above, the optical wavelength conversion unit 13 has an axially symmetric shape with respect to the straight line A in FIG.

  The concave curved surface portion is typically preferably a gentle curved surface, but microscopic unevenness (surface roughness Ra: about 0.2 × d or less) may be formed on the surface.

  Fig.7 (a) is a photograph which shows the external appearance of the light wavelength conversion part 13 formed from the silicone resin, and FIG.7 (b) is a photograph which shows the side surface of the other light wavelength conversion part 13 formed from the silicone resin. is there. The light wavelength conversion unit 13 illustrated in FIG. 7A has a substantially truncated cone shape, but the light wavelength conversion unit 13 illustrated in FIG. 7B has a substantially cylindrical shape. Each of the optical wavelength converters 13 has a concave curved surface on its side surface. FIG. 7B shows the “minimum height” and “maximum height” of the optical wavelength converter. When the light wavelength conversion part having an average thickness of less than 0.5 mm is formed from a resin, as shown in FIG. 7B, the thickness of the resin varies depending on the location. There may be variations in the height of the upper surface of the light wavelength conversion portion when used as a reference, but this does not cause any particular problem.

  Thus, a concave curved surface is intentionally formed on the side surface (and the top surface) of the light wavelength conversion unit 13 of the present embodiment. According to the inventor's experiment and computer simulation, it has been found that the presence of this curved surface increases the light utilization efficiency and increases the luminous flux.

  In order to define this curved surface, consider the curvature of the cross-sectional shape shown in FIG. This curvature is measured based on a cross section of the light wavelength conversion unit cut so as to cross the side surface (region where the recess exists) of the light wavelength conversion unit 13 by a plane perpendicular to the main surface of the substrate 11. In the cross section of the optical wavelength converter 13 shown in FIG. 2, a curve corresponding to the concave curved surface of the side surface appears. A value R / t obtained by dividing the curvature radius R of the curve by the thickness t of the light wavelength conversion unit 13 is preferably in the range of 0.5 or more and 8.5 or less. The reason is that when the value R / t exceeds 8.5, the difference from the conventional LED light source in which the concave curved surface is not provided on the side surface of the light wavelength conversion unit 13 is substantially eliminated. In addition, when the value R / t decreases below 0.5, the light use efficiency decreases instead. This value R / t is more preferably in the range of 1.1 to 3.7.

  In addition, it is preferable that the value d / t which divided the depth d of the recessed part in the side surface of the light wavelength conversion part 13 by the thickness t of the light wavelength conversion part 13 exists in the range of 0.03 or more and 0.5 or less. Since the thickness t does not change so much as the digit changes depending on the LED light source, in a typical LED light source, the depth d of the recess formed on the side surface of the light wavelength conversion unit 13 is 0.01 mm or more and 0.17 mm or less. It is preferable to be within the range.

  The above curve shown in FIG. 2 does not have to be a complete arc, but is preferably a gentle curve having no inflection point. However, even if a protrusion or a recess is formed on a part of the side surface of the light wavelength conversion section, there is no problem as long as a concave curved surface is formed as a whole.

(Embodiment 1 of manufacturing method)
Next, a first embodiment of a method for producing an LED light source according to the present invention will be described with reference to FIGS.

  First, as shown in FIG. 8A, the printing stencil 20 is brought into contact with the main surface of the substrate 11 on which the LED elements 12 are mounted. As shown in FIG. 9, the printing stencil 20 is a blade-like member provided with a plurality of openings 19. The positions and shapes of the openings 19 are formed so as to surround corresponding elements among the LED elements 12 mounted on the substrate 11. The opening 19 of the printing stencil shown in FIG. 9 is defined by a cylindrical space.

  Next, as shown in FIG. 8B, a resin (phosphor resin) 16 containing a fluorescent substance is supplied onto the printing stencil 20, and the printing resin stencil is pressed while pressing the phosphor resin 16 with a squeegee 17. The top surface of 20 is scanned. As a result, the inside of the opening 19 of the printing stencil 20 is filled with the phosphor resin 16.

  In the present embodiment, the phosphor resin 16 is formed from a resin material having a high viscosity. Therefore, when the printing stencil 20 is separated from the substrate 11 as shown in FIG. 8C, a resin pattern 13 ′ made of the phosphor resin 16 is formed on the substrate 11 as shown in FIG. 8D. Is done. The resin pattern 13 ′ eventually becomes the light wavelength conversion portion 13, but in this state, no concave curved surface portion is formed on the side surface.

  Next, in this embodiment, as shown in FIG. 8E, the side surface of the resin pattern 13 ′ is depressed by applying a force to the side surface of the resin pattern 13 ′ with the pressing member 21, thereby forming a concave curved surface portion. To do. In this way, the optical wavelength conversion part 13 having a concave curved surface part on the side surface can be formed.

  When a force is applied to the side surface of the resin pattern 13 ′, the upper surface of the resin pattern 13 ′ may be deformed to form a concave curved surface that is recessed downward. In this embodiment, the resin pattern 13 'is cured after the printing stencil 20 is separated from the substrate 11, but the timing and conditions of the curing are optimized according to the resin used.

(Embodiment 2 of manufacturing method)
Next, a second embodiment of a method for manufacturing an LED light source according to the present invention will be described with reference to FIGS. 10 (a) to 10 (d).

  First, as shown in FIG. 10A, the printing stencil 120 is brought into contact with the main surface of the substrate 11 on which the LED elements 12 are mounted. The upper surface of the printing stencil 120 has the same form as the printing stencil 20 shown in FIG. However, the cross-sectional structure of the printing stencil 120 used in the present embodiment is greatly different from the cross-sectional structure of the printing stencil 20. Specifically, the printing stencil 120 includes two plates 121 and 123 formed of a relatively rigid material such as metal, and a rubber having high elasticity sandwiched between the plates 121 and 123. And an elastic body layer 122 made of Similar to the printing stencil 20, the printing stencil 120 is provided with a plurality of openings (through holes) 19.

  Next, as shown in FIG. 10B, the phosphor resin 16 is supplied onto the printing stencil 120, and the upper surface of the printing stencil 120 is scanned while pressing the phosphor resin 16 with the squeegee 17. At this time, by applying pressure in the longitudinal direction to the printing stencil 120, the elastic body layer 122 is compressed in the thickness direction, whereby the side surface of each opening 19 is convex toward the center of the opening. Extrude into. In this state, the phosphor resin 16 is supplied into the opening 19, and the inside of the opening 19 of the printing stencil 120 is embedded with the phosphor resin 16.

  Also in this embodiment, since the phosphor resin 16 is formed from a resin material having a high viscosity (a resin mainly composed of silicone), printing is performed from the substrate 11 as shown in FIGS. 10 (c) and 10 (e). When the stencil 120 is released, the light wavelength conversion section 13 having a concave curved surface formed on the side surface is formed on the substrate 11.

  In this embodiment, as shown in FIGS. 11A and 11B, a printing stencil 120 having a layer (member) formed of an elastic body such as rubber is used as an intermediate layer, and an opening is formed by applying pressure. However, the present invention is not limited to such a case. For example, as shown in FIGS. 11C and 11D, a two-layer printing stencil 125 in which a plate 121 having relatively high rigidity is provided only on the upper surface side of the elastic layer 122 may be used.

  Alternatively, a printing stencil having a two-layer structure in which the plate 121 is provided only on the lower surface side of the elastic layer 122, or a printing stencil having only the elastic layer 122 may be used. Further, instead of the elastic body layer 122, a printing stencil may be formed using a structure that is easily deformed by holding a fluid therein or other easily deformable material. In addition, although resin used in this Embodiment 1 and 2 has thermosetting property, it can be hardened by performing heat processing (for example, heat processing hold | maintained at 120 degreeC for 1 hour) after said process process. it can. Thereafter, the lens resin is molded by, for example, transfer molding.

  In addition, the formation method of the light wavelength conversion part in this invention is not limited to the method which concerns on embodiment mentioned above.

  Hereinafter, computer simulations performed on the light beams emitted from the LED light source of the present invention and the conventional LED light source will be described.

  FIG. 3 shows the configuration of a conventional LED light source. In the LED illumination light source 300 shown in FIG. 3, the components other than the cylindrical resin portion 60 have the same structure as the components of the LED illumination light source 100 of the present embodiment shown in FIG. The cylindrical resin portion 60 is greatly different from the light wavelength conversion portion 13 in the present embodiment in the shape of the surface. That is, the conventional cylindrical resin portion 60 has a cylindrical shape with the bottom surface as the surface in contact with the substrate 11, and no concave curved surface portion is formed on the top and side surfaces thereof. The cylindrical side surface is a “curved surface”, but is convex and not concave.

<Simulation result 1>
The luminous flux emitted from the LED light source 100 was obtained by computer simulation. The conditions for the simulation are as follows.

(Simulation conditions)
-Reflectance of substrate 11: 0.5
-Reflectance of reflector 14: 0.82
A uniform and uniform light beam is emitted in all directions from the light wavelength conversion unit 13 per unit surface area.
-Refractive index n1: 1.4 of the optical wavelength converter 13
-Refractive index n2 of translucent member 15: 1.6
Translucent member 15: hemispherical shape Transmissivity of translucent member 15: 96% / mm
-The total number of light rays from the surface of the light wavelength conversion unit 13 is 200,000 (assuming the first resin part is a light source)

  Moreover, the following four types of shapes were given to the light wavelength conversion unit 13.

Shape number 1: a shape having a concave curved surface on both the upper surface and the side surface of the substantially truncated cone shape (the shape shown in FIG. 2)
Shape number 2: a shape in which only the substantially truncated cone-shaped upper surface 131 has a concave curved surface (not shown)
Shape number 3: a shape in which only the substantially frustoconical side surface 132 has a concave curved surface (not shown)
Shape number 4 (comparative example): a truncated conical shape (corresponding to a structure in which the cylindrical resin portion 60 shown in FIG. 3 is changed to a truncated cone shape).

  The luminous flux emitted from the LED light source 100 was calculated under the above conditions. The value of the luminous flux obtained by the calculation was normalized with the luminous flux of the comparative example indicated by the shape number 4 as 100. The normalized luminous flux is shown in Table 1 below.

  As can be seen from Table 1, the light flux increases by forming a concave curved surface portion on the upper surface or side surface of the light wavelength conversion portion. The luminous flux is increased by 3% by forming the concave curved surface portion on the upper surface of the light wavelength conversion portion, and is improved by 4% by forming it on the side surface of the light wavelength conversion portion. When the concave curved surface portion is formed on both the upper surface and the side surface of the light wavelength conversion portion, an effect of improving the luminous flux by 10% can be obtained.

<Simulation result 2>
Next, a virtual light emitting point is defined in the light wavelength conversion unit 13 under substantially the same conditions as the above simulation conditions, and light isotropically emitted from the light emitting point is formed. The luminous flux of the LED light source was calculated. The value of the luminous flux obtained by the calculation was normalized with the luminous flux of the comparative example indicated by the shape number 4 as 100.

(Simulation conditions)
・ The number of light rays is 200,000 at each light emitting point. ・ The calculated light emitting points are two places, the center of the light wavelength conversion unit 13 and the vicinity of the side surface side of the light wavelength conversion unit 13, as shown in FIG. Is the same as simulation result 1.

  The simulation results are shown in Table 2.

  From Table 2, by forming a concave curved surface portion on any one of the side surface and the upper surface of the light wavelength conversion portion 13 regardless of the position where the virtual light emission point exists in the light wavelength conversion portion 13, It can be seen that a luminous flux increasing effect can be obtained.

<Analysis of simulation results>
Hereinafter, the simulation results will be considered.

  When the light emitted from the light wavelength converter 13 (n1 = 1.41) is incident on the translucent member 15 (refractive index n2 = 1.55), that is, n1 <n2 (Expression 1) If is true, there is no critical angle and there is no total reflection. Therefore, all the emitted light from the light wavelength conversion unit 13 is transmitted through the translucent member 15, so it is considered that there is no loss of light at the interface between the light wavelength conversion unit 13 and the translucent member 15.

  When a concave curved surface is formed at the interface between the light wavelength conversion unit 13 and the translucent member 15 as in the present embodiment, a lens effect occurs at the interface. For this reason, the condensing property of the light emitted from the light wavelength conversion unit 13 is enhanced, and the stray light in the translucent member 15 is reduced. As a result, the luminous flux is increased. This is because when the stray light of the translucent member 15 is reduced, the light extraction efficiency from the translucent member 15 is improved, and as a result, the luminous flux from the LED light source is increased.

  As described above, by forming the concave curved surface portion on the side surface of the light wavelength conversion portion 13, it is possible to obtain an effect that the light extraction efficiency is improved.

  In this embodiment, the refractive index satisfies the relationship of n1 <n2, but even when the relationship of n1> n2 is satisfied, the light extraction efficiency is improved by the concave curved surface formed on the side surface of the light wavelength conversion unit. Improvement effect is obtained. However, in this case, since a critical angle exists, it is preferable to optimize the shapes of the light wavelength conversion unit 13 and the translucent member 15 in consideration of the ratio of n1 and n2.

  In the present embodiment, the light wavelength conversion unit 13 has a substantially truncated cone shape, but the shape of the light wavelength conversion unit 13 is not limited to such a shape, and a concave curved surface is formed on the side surface. The effect of improving the light extraction efficiency can be obtained.

  When the distance from the center of the LED element 12 to the end of the light wavelength conversion unit 13 containing the fluorescent material is substantially equal to the substrate 11, the wavelength conversion by the fluorescent material in the light wavelength conversion unit 13 is substantially uniform. Therefore, the emitted light from the fluorescent material becomes uniform, and the color unevenness of the emitted light from the LED light source 100 can be reduced. Examples of the shape of the light wavelength conversion unit 13 are shown in FIGS. In FIG. 5 and FIG. 6, the description of the translucent member 15 and the reflecting plate 14 is omitted for simplicity.

  FIG. 5A is a schematic top view of the LED light source 500, and FIG. 5B is a schematic side view of the LED light source 500. The light wavelength conversion unit 13 in the LED light source 500 has a substantially cylindrical shape, but a concave curved surface portion is formed on the upper surface and side surfaces thereof.

  FIG. 6A is a schematic top view of the LED light source 600, and FIG. 6B is a schematic side view of the LED light source 600. The light wavelength conversion unit 13 in the LED light source 900 has a substantially square frustum shape, but the corners of the hypotenuse are rounded. A concave curved surface portion is formed on the upper surface and side surfaces of the optical wavelength conversion portion 13.

  The basic shape of the light wavelength conversion unit of the present invention is not limited to the shape described above, and may be, for example, a substantially pentagonal frustum or a substantially hexagonal frustum. In any case, it is preferable that the LED element 12 is disposed at a substantially central portion of a substantially bottom surface of the light wavelength conversion unit 13.

  In general, the larger the area ratio of the concave curved surface portion of the surface area of the light wavelength conversion portion 13, the higher the light extraction efficiency. For this reason, it is preferable that a concave curved surface is formed in a wider area among the entire surface of the light wavelength conversion unit 13.

  The translucent member 15 functions as a convex lens, but the translucent member 15 has other shapes as long as it has an optical function required for various uses. It may be.

  In the present embodiment, the reflecting plate 14 is provided on the main surface of the substrate 11, but the reflecting surface may be formed directly on the main surface of the substrate. The reflection structure is arbitrary as long as the directivity of the light beam can be improved.

  In the present embodiment, the light wavelength conversion unit 13 is formed from a resin material containing silicone resin as a main component, and the translucent member 15 is formed from a resin material containing epoxy resin as a main component. Alternatively, the light wavelength conversion unit 13 and the translucent member 15 may be formed.

  In order to reduce color unevenness, it is preferable to match the center of the LED element 12 with the center of the light wavelength conversion unit 13. In order to improve the light extraction efficiency and further reduce the unevenness of the light emitted from the LED light source, the center of the LED element 12, the center of the light wavelength converter 13, the center of the opening of the reflector 14, and the transmission It is preferable to match all of the centers of the optical members 15.

  The LED light source of the present invention has high light extraction efficiency and is useful as a light source in lighting equipment and other various devices.

It is a schematic sectional drawing of the LED light source 100 concerning preferable embodiment of this invention. It is sectional drawing to which the light wavelength conversion part 13 with which the LED light source 100 is provided was expanded. It is a schematic sectional drawing which shows the conventional LED light source 300. It is the schematic which shows the position of the light emission point at the time of calculating | requiring a simulation result. (A) is a top view which shows an example of the shape of the light wavelength conversion part 13, (b) is the sectional drawing. (A) is a top view which shows the other example of the shape of the light wavelength conversion part 13, (b) is the sectional drawing. (A) And (b) is a photograph which shows the specific example of the light wavelength conversion part 13 formed from resin, respectively. (A)-(e) is process sectional drawing which shows 1st Embodiment of the method of manufacturing the LED light source by this invention. It is a top view which shows the stencil for printing used suitably by embodiment of this invention. (A)-(d) is process sectional drawing which shows 2nd Embodiment of the method of manufacturing the LED light source by this invention. (A) And (b) is sectional drawing which shows the structure and operation | movement of the printing stencil 120 shown to Fig.10 (a), (c) and (d) are the structure and operation | movement of the other printing stencil 125. FIG. It is a figure which shows typically the parameter which prescribes | regulates the shape of the concave curved surface part in a light wavelength conversion part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Board | substrate 12 LED element 13 Light wavelength conversion part 13 'Resin pattern 14 Reflector 15 Translucent member 20 Printing stencil 60 Cylindrical resin part 120 Printing stencil 125 Printing stencil

Claims (19)

At least one LED element mounted on the main surface of the substrate;
A light wavelength converter that includes a fluorescent material that converts light emitted from the LED element into light having a wavelength longer than the wavelength of the light, and covers at least a part of the LED element;
An LED light source comprising:
The side surface of the light wavelength conversion unit is an LED light source having at least one concave curved surface portion.   The LED light source of Claim 1 provided with the translucent member which covers at least one part of the said light wavelength conversion part. A reflective surface spaced from the side surface of the light wavelength conversion unit;
A translucent member covering at least a part of the light wavelength conversion unit;
With
The LED light source according to claim 2, wherein a refractive index of the translucent member is different from a refractive index of the light wavelength conversion unit.   The LED light source according to claim 3, wherein a refractive index of the translucent member is larger than a refractive index of the light wavelength conversion unit. The translucent member is made of resin,
The LED light source according to claim 4, wherein the translucent member fills a gap between the side surface of the light wavelength conversion unit and the reflection surface.   The LED light source according to claim 3, wherein the translucent member functions as a lens.   The LED light source according to claim 1, wherein the light wavelength conversion unit is formed of a resin containing the fluorescent material. The cross section of the light wavelength conversion unit cut out across the recess on the side surface of the light wavelength conversion unit by a plane perpendicular to the main surface of the substrate has an outer shape including a curve corresponding to the recess,
The LED according to any one of claims 1 to 7, wherein a value R / t obtained by dividing a curvature radius R of the curve by a thickness t of the light wavelength conversion unit is in a range of 0.5 or more and 8.5 or less. light source.   The value d / t obtained by dividing the depth d of the concave portion on the side surface of the light wavelength conversion portion by the thickness t of the light wavelength conversion portion is in the range of 0.03 or more and 0.5 or less. The LED light source according to any one of 6.   The LED light source according to claim 9, wherein a depth d of the concave portion on the side surface of the light wavelength conversion unit is in a range of 0.01 mm to 0.17 mm.   The LED light source according to claim 1, wherein the light wavelength conversion unit has a substantially cylindrical shape, and the side surface of the substantially cylindrical shape forms the concave curved surface portion.   The LED light source according to claim 1, wherein the light wavelength conversion unit has a substantially truncated cone shape, and a side surface of the substantially truncated cone shape forms the concave curved surface portion. A plurality of LED elements arranged on the main surface of the substrate;
A plurality of reflective surfaces surrounding each side surface of the plurality of LED elements;
Including a fluorescent material that converts light emitted from the LED element into light having a wavelength longer than the wavelength of the light, and a plurality of light wavelength conversion units each covering the corresponding LED element;
A plurality of translucent members each covering a corresponding light wavelength converter;
An LED light source comprising:
The side surface of each light wavelength converter has at least one concave curved surface portion,
The translucent member is an LED light source that fills a gap between the side surface of the light wavelength conversion unit and the reflection surface. A printing plate used for forming a resin pattern on a substrate,
A plate-like member having an upper surface, a lower surface, and at least one through hole connecting the upper surface and the lower surface;
The printing plate, wherein the inner wall surface of the through hole in the plate-shaped member forms a convex curved surface that protrudes toward the center of the through hole while at least the resin filled in the through hole is cured.   The printing plate according to claim 14, wherein the plate-like member is formed of a material whose shape changes flexibly according to an external force.   The printing plate according to claim 15, wherein the plate-like member is formed of an elastic body.   The printing plate according to claim 15 or 16, further comprising a plate in contact with at least one of an upper surface and a lower surface of the plate-like member. A step (A) of mounting at least one LED element on the main surface of the substrate; and a fluorescent material that converts light emitted from the LED element into light having a wavelength longer than the wavelength of the light, A step (B) of forming an optical wavelength conversion part covering at least a part on the substrate, and a manufacturing method of an LED light source,
The said process (B) is a manufacturing method of an LED light source including the process of forming at least 1 concave curved surface part in the side surface of the said light wavelength conversion part. The step (B)
A step (b1) of forming an isolated pattern of the material constituting the light wavelength conversion portion on the substrate;
A step (b2) of deforming a side surface of the isolated pattern to form the concave curved surface portion;
The manufacturing method of Claim 18 containing this.