Light emitting device utilizing a LED chip
A light emitting device ( 1 ) includes a LED chip ( 10 ) as well as a mounting substrate ( 20 ) on which the LED chip ( 10 ) is mounted. Further, the light emitting device ( 1 ) includes a cover member ( 60 ) and a color conversion layer ( 70 ). The cover member ( 60 ) is formed to have a dome shape and is made of a translucency inorganic material. The color conversion layer ( 70 ) is formed to have a dome shape and is made of a translucency material (such as, a silicone resin) including a fluorescent material excited by light emitted from the LED chip ( 10 ) and emitting light longer in wavelength than the light emitted from the LED chip ( 10 ). The cover member ( 60 ) is attached to the mounting substrate ( 20 ) such that there is an air layer ( 80 ) between the cover member ( 60 ) and the mounting substrate ( 20 ). The color conversion layer ( 70 ) is superposed on a light-incoming surface or a light-outgoing surface of the cover member ( 60 ).
1. A light emitting device comprising:
a LED chip;
a mounting substrate on which said LED chip is mounted;
a cover member formed to have a dome shape and made of a translucency inorganic material; and
a color conversion layer formed to have a dome shape and made of a translucency material including a fluorescent material excited by light emitted from said LED chip and emitting light longer in wavelength than the light emitted from said LED chip,
wherein said cover member is attached to said mounting substrate such that there is an air layer between said cover member and said mounting substrate, and
wherein said color conversion layer is superposed on a light-incoming surface or a light-outgoing surface of said cover member.
2. A light emitting device as set forth in claim 1 , wherein
said light emitting device comprises a translucency encapsulation member configured to encapsulate said LED chip on a mounting surface, where said LED chip is mounted, of said mounting substrate,
said air layer being interposed between said cover member and said translucency sealing member.
3. A light emitting device as set forth in claim 2 , wherein
said light emitting device comprises a wavelength selection filter layer configured to allow a transmission of the light emitted from said LED chip and to reflect the light emitted from said fluorescent material of said color conversion layer,
said wavelength selection filter layer being formed on a light-outgoing surface of said translucency encapsulation member, and
said air layer being interposed between said cover member and said wavelength selection filter layer.
4. A light emitting device as set forth in claim 2 , wherein
said translucency encapsulation member is made of glass.
5. A light emitting device as set forth in claim 1 , wherein
said light emitting device comprises a wavelength selection filter layer configured to allow a transmission of the light emitted from said LED chip and to reflect the light emitted from said fluorescent material of said color conversion layer,
said color conversion layer being superposed on said light-outgoing surface of said cover member, and
said wavelength selection filter layer being superposed on said light-incoming surface of said cover member.
6. A light emitting device as set forth in claim 1 , wherein
said color conversion layer includes a translucency coat configured to coat said fluorescent material,
said translucency coat having a refractive index in the range of a refractive index of said fluorescent material to a refractive index of said translucency material.
7. A light emitting device as set forth in claim 1 , wherein
said mounting substrate includes a dielectric substrate where a patterned conductor electrically connected to said LED chip is formed and a heat conductive member extending through said dielectric substrate in a thickness direction thereof,
said heat conductive member being made of a material higher in heat conductivity than said dielectric substrate, and
said color conversion layer being thermally coupled to said heat conductive member.
8. A light emitting device as set forth in claim 1 , wherein
said light emitting device comprises a reflective member made of a material higher in reflectance than said mounting substrate,
said reflective member being interposed between said mounting substrate and an edge of each said cover member and said color conversion layer adjacent to said mounting substrate.