Lighting apparatus
According to one embodiment, a lighting apparatus comprises a light source configured to generate heat, a transparent heat transfer member located near the light source and having transparency and heat conductivity, and a means for transferring heat from the light source to the transparent heat transfer member.
1. A lighting apparatus comprising:
a light source configured to generate heat;
a transparent heat transfer member located near the light source and having transparency to visible light, a heat-resistant temperature equivalent to or greater than that of the light source, and heat conductivity;
a heat transfer means for transferring heat from the light source to the transparent heat transfer member; and
a protective member that:
is formed of a material that:
is transparent or translucent to visible light,
has a heat-resistant temperature equivalent to or greater than that of the light source,
has a mechanical strength sufficient to withstand impacts when dropped,
has flame retardance, and
is different from the transparent heat transfer member; and
covers a surface of the transparent heat transfer member.
2. The lighting apparatus of claim 1 , wherein the heat transfer means is a transparent member with a light receiving surface located near and opposite a light emitting surface of the light source, and the transparent member is in tight contact with and transfers heat to the transparent heat transfer member.
3. The lighting apparatus of claim 2 , wherein:
the heat transfer means is a glass lens having: a back surface which contacts a surface of a substrate on which the light source is provided,
a recess which is provided on the back surface and in which the light source is housed and arranged in a non-contact state,
a surface which refracts light that passes through to distribute the light, and
a side surface which is in tight contact with the transparent heat transfer member.
4. The lighting apparatus of claim 1 , wherein the transparent heat transfer member is a glass globe having a transmittance of 92% or higher, a heat-resistant temperature of 100° C. or higher, and heat conductivity of 1.0 W/mK or higher.
5. The lighting apparatus of claim 4 , wherein the globe has a means for diffusing light.
6. The lighting apparatus of claim 4 , wherein the light source is provided on an inner surface of the globe, and the heat transfer means is an adhesive having transparency and heat conductivity and bonding the light source to an inner surface of the globe.
7. The lighting apparatus of claim 4 , wherein at least one of the globe and the protective member has light diffusivity.
8. The lighting apparatus of claim 5 , wherein the means for diffusing light includes a scatterer provided on an inner surface or a surface of the globe.
9. The lighting apparatus of claim 1 , wherein the transparent heat transfer member is a glass globe having a transmittance of 92% or higher, a heat-resistant temperature of 100° C. or higher, and heat conductivity of 1.0 W/mK or higher, and the heat transfer means is a glass lens having a heat-resistant temperature of 100° C. or higher and heat conductivity of 1.0 W/mK or higher.
10. The lighting apparatus of claim 1 , wherein the transparent heat transfer member has a light receiving surface located near and opposite a light emitting surface of the light source.
11. The lighting apparatus of claim 1 , further comprising a power supply circuit configured to supply electricity to the light source.
12. The lighting apparatus of claim 1 , wherein the light source is a LED, and the transparent heat transfer member and the heat transfer means for transferring heat to the transparent heat transfer member have heat resistance at least equivalent to heat resistance of the LED.
13. The lighting apparatus of claim 1 , further comprising a back surface side he
at transfer member having heat conductivity and to which the light source is attached.
14. The lighting apparatus of claim 13 , wherein the back surface side heat transfer member is a metal enclosure having excellent heat conductivity.
15. The lighting apparatus of claim 13 , wherein the back surface side heat transfer member is a substrate on which the light source is mounted.
16. The lighting apparatus of claim 1 , wherein the protective member:
has a light transmittance of 85% or higher,
has a heat-resistant temperature of 100° C. or higher,
has a mechanical strength sufficient to withstand impacts when dropped, and
has flame retardance.
17. The lighting apparatus of claim 1 , further comprising:
an air layer provided between the surface of the transparent heat transfer member and the protective member.