Light source unit and road illumination device equipped with light source unit
A light source unit includes a light emitting module which has a printed wiring board and a plurality of light emitting diode elements mounted on the board, and a light-transmissive light distribution adjustment portion which covers the light emitting module, in which the board has a fluorescent layer containing fluorescent particles over a surface on which the light emitting diode elements are mounted, and the light distribution adjustment portion includes a portion having a convex shape outward from the board side, is spaced apart from the plurality of light emitting diode elements and from the fluorescent layer, commonly covers the plurality of light emitting diode elements and the fluorescent layer, and diffuses and distributes emission light from the light emitting diode elements and luminescence from the fluorescent layer.
1. A light source unit comprising:
a light emitting module which has a printed wiring board and a plurality of light emitting diode elements mounted on the printed wiring board; and
a light-transmissive light distribution adjustment portion which covers the light emitting module,
wherein the printed wiring board has a fluorescent layer containing fluorescent particles over a surface on which the light emitting diode elements are mounted,
the light distribution adjustment portion includes a portion having a convex shape outward from the board side, is spaced apart from the plurality of light emitting diode elements and from the fluorescent layer, commonly covers the plurality of light emitting diode elements and the fluorescent layer, and diffuses and distributes emission light from the light emitting diode elements and luminescence from the fluorescent layer,
each of the light emitting diode elements is a Chip Scale Package (CSP) in which a flip chip is incorporated, and a fluorescent substance of the CSP is provided separately from the fluorescent layer, and
the fluorescent layer is provided in an area of 80% or more of an surface of an insulation layer of the printed wiring board.
2. The light source unit according to claim 1 ,
wherein the light distribution adjustment portion emits the emission light from the light emitting diode elements and the luminescence from the fluorescent layer, and distributes the light in a batwing-type illuminance distribution.
3. The light source unit according to claim 1 ,
wherein the light distribution adjustment portion includes a convex curved surface protruding outward from the board side.
4. The light source unit according to claim 3 ,
wherein the light distribution adjustment portion has a bowl-like shape or a semi-cylindrical shape.
5. The light source unit according to claim 3 ,
wherein the printed wiring board has a rectangular shape,
an emission surface of the light distribution adjustment portion, which emits the emission light from the light emitting diode elements and the luminescence from the fluorescent layer, is a convex curved surface, and
in a cross-sectional view along a plane orthogonal to a longitudinal direction of the board and a surface direction of the board and passing through a center portion of the board, in a case where a thickness of the light distribution adjustment portion in a normal direction of the convex curved surface is denoted as d, a thickness d at an end portion of the convex curved surface is larger than a thickness d at a top portion of the convex curved surface.
6. The light source unit according to claim 5 ,
wherein a value of the thickness d gradually increases from the top portion of the convex curved surface to the end portion of the convex curved surface.
7. The light source unit according to claim 1 ,
wherein the light distribution adjustment portion includes a light receiving surface which receives the emission light from the light emitting diode elements and the luminescence from the fluorescent layer, and an emission surface which emits the received light, and
the emission surface of the light distribution adjustment portion includes irregularities composed of a mountain portion protruding toward outward and a valley portion adjacent to the mountain portion and recessed inward.
8. The light source unit according to claim 1 ,
wherein the light distribution adjustment portion includes a cylindrical lens portion.
9. The light source unit according to claim 1 ,
wherein the light distribution adjustment portion includes a Fresnel lens portion.
10. The light source unit according to claim 1 ,
wherein the light emitting module includes a first light emitting module and a second light emitting module,
the first light emitting module and the second light emitting module do not exist over the same plane, and
an angle formed by a back surface of an element mounting surface of the board in the first light emitting module, on which the light emitting diode elements are mounted, and a back surface of an element mounting surface of the board in the second light emitting module, on which the light emitting diode elements are mounted, is equal to or more than 0° and equal to or less than 120°.
11. The light source unit according to claim 1 , further comprising:
a heat sink over a surface side of the board opposite to the surface on which the light emitting diode elements are mounted.
12. The light source unit according to claim 11 , further comprising:
a cooling fan.
13. The light source unit according to claim 1 ,
wherein the fluorescent particles include one or two or more kinds selected from the group consisting of a CASN-based fluorescent substance, an SCASN-based fluorescent substance, a La 3 Si 6 N 11 -based fluorescent substance, a Sr 2 Si 5 N 8 -based fluorescent substance, a Ba 2 Si 5 N 8 -based fluorescent substance, an α-sialon-based fluorescent substance, a β-sialon-based fluorescent substance, a LuAG-based fluorescent substance, and a YAG-based fluorescent substance.
14. The light source unit according to claim 1 ,
wherein a median diameter D 50 of the fluorescent particles is equal to or more than 1 μm and equal to or less than 20 μm.
15. The light source unit according to claim 1 ,
wherein a thickness of the fluorescent layer is equal to or less than 150 μm.
16. The light source unit according to claim 1 ,
wherein the fluorescent layer contains a transparent resin which is transparent to visible light and the fluorescent particles dispersed in the transparent resin.
17. The light source unit according to claim 1 ,
wherein the fluorescent layer is a cured product of a fluorescent coating material, and
the fluorescent coating material contains fluorescent particles and a curable resin component.
18. The light source unit according to claim 17 ,
wherein the curable resin component includes one or two or more kinds selected from the group consisting of a silicone resin and a (meth)acrylate monomer.
19. The light source unit according to claim 1 ,
wherein the light source unit is used for road illumination.
20. The light source unit according to claim 1 ,
wherein, in a case where a fluorescence peak wavelength of the fluorescent particles when luminescence of the light emitting diode elements is used as excitation light is denoted as Δ1 and a luminescence wavelength of the light emitting diode elements is denoted as λ2, an absolute value Δλ of a difference between λ1 and λ2 is equal to or less than 50 nm.
21. The light source unit according to claim 1 , further comprising:
a body including the light emitting module,
wherein the light distribution adjustment portion is detachable from the body.
22. The light source unit according to claim 1 , further comprising:
an attaching portion for detachably installing the light source unit to a housing of a road illumination device.
23. A road illumination device comprising:
a housing; and
a light source unit housed in the housing,
wherein the housing has a window portion for transmitting light emitted from the light source unit and a light source unit installing portion for installing the light source unit,
the light source unit is the light source unit according to claim 22 , and
the light source unit is detachably installed to the light source unit installing portion.
24. A light source unit comprising:
a light emitting module which has a printed wiring board and a plurality of light emitting diode elements mounted on the printed wiring board; and
a light-transmissive light distribution adjustment portion which covers the light emitting module,
wherein the printed wiring board has a fluorescent layer containing fluorescent particles over a surface on which the light emitting diode elements are mounted,
the light emitting module includes a first light emitting module and a second light emitting module,
the first light emitting module and the second light emitting module do not exist over the same plane,
an angle formed by a back surface of a mounting surface of the light emitting diode elements in the first light emitting module and a back surface of a mounting surface of the light emitting diode elements in the second light emitting module is equal to or more than 0° and equal to or less than 120°,
each of the light emitting diode elements is a Chip Scale Package (CSP) in which a flip chip is incorporated, and a fluorescent substance of the CSP is provided separately from the fluorescent layer, and
the fluorescent layer is provided in an area of 80% or more of an surface of an insulation layer of the printed wiring board.