Lighting device, luminaire and manufacturing method
A lighting device ( 10 ) is disclosed comprising a glass housing ( 20 ) delimiting an optical chamber ( 21 ), wherein at least one solid state lighting (SSL) element ( 30 ) is mounted within the optical chamber. The optical chamber ( 21 ) further comprises a light exit window ( 50 ) mounted in an aperture ( 23 ) of the optical chamber opposite the at least one solid state lighting element, the light exit window comprising a sealing plate sealed to the glass housing by a glass seal ( 51 ); and a light-transmissive thermal barrier ( 40 ) extending across the optical chamber in between the sealing plate and the at least one solid state lighting element, which protects the at least one SSL element ( 30 ) from thermal damage during the formation of the glass seal ( 51 ). Also disclosed are a luminaire including such a lighting device and a method of manufacturing such a lighting device.
1. A lighting device comprising a glass housing delimiting an optical chamber, wherein at least one solid state lighting element is mounted within the optical chamber, the optical chamber further comprising:
a light exit window mounted in an aperture of the optical chamber opposite the at least one solid state lighting element, the light exit window comprising a sealing plate sealed to the glass housing by a glass seal; and
a light-transmissive thermal barrier extending across the optical chamber in between the sealing plate and the at least one solid state lighting element.
2. The lighting device of claim 1 , wherein the sealing plate is a glass plate.
3. The lighting device of claim 1 , wherein the glass seal is made of a glass having a melting point below 500° C.
4. The lighting device of claim 1 , wherein the glass seal is made of a soft glass or a solder glass.
5. The lighting device of claim 1 , wherein the light-transmissive thermal barrier is a further glass plate.
6. The lighting device of claim 1 , wherein the light-transmissive thermal barrier is affixed to the housing by screws, an adhesive or cement.
7. The lighting device of claim 1 , wherein the sealing plate and the light-transmissive thermal barrier each lie in a plane perpendicular to the optical axis of the lighting device.
8. The lighting device of claim 1 , wherein the glass housing comprises a reflective coating around the optical chamber.
9. The lighting device of claim 1 , wherein the lighting device is a light bulb.
10. A luminaire comprising the lighting device of claim 1 .
11. The luminaire of claim 10 , wherein the luminaire is a poultry farming luminaire.
12. A method of manufacturing a lighting device, the method comprising:
providing a glass housing delimiting an optical chamber, wherein at least one solid state lighting element is mounted within the optical chamber, the optical chamber further comprising a light exit aperture opposite the at least one solid state lighting element;
affixing a light-transmissive thermal barrier to the glass housing in between the light exit aperture and the at least one solid state lighting element such that the light-transmissive thermal barrier extends across the optical chamber;
placing a sealing plate in the light exit aperture to define a light exit window of the lighting device; and
sealing the sealing plate to the glass housing by depositing a glass powder in between the sealing plate and the housing and melting the glass powder with a flame.
13. The method of claim 12 , wherein melting the glass powder with the flame comprises melting the glass powder at a temperature below 500° C.
14. The method of claim 12 , wherein the glass powder is a soft glass powder or a solder glass powder.
15. The method of claim 12 , wherein affixing the light-transmissive thermal barrier to the glass housing comprises securing the light-transmissive thermal barrier to the glass housing with screws, an adhesive or cement.