Lighting device with a thermally conductive fluid

1. A lighting device comprising:

a base for connection to a socket;

a first at least in part light-transmissive surface structure at least in part delimiting a fluidly sealed, closed first space which includes a thermally conductive fluid therein, wherein the first light-transmissive surface structure is mounted to the base; and

at least one second at least in part light-transmissive surface structure at least in part defining at least one second space which is fluidly connected to the exterior of the lighting device through the base, which at least one second surface structure is contained entirely within the first surface structure and the base;

wherein the at least one second surface structure has a closed first end and a second, opposite end adjacent the base that fluidly couples the second space to the exterior of the lighting device through the base;

wherein the at least one second surface structure comprises a thermally conductive interface between the second space and the first space, the thermally conductive interface being coupled to at least one light-emitting element arranged within the second space and configured to emit light such that at least a portion of the emitted light passes through the at least one second surface structure and subsequently through the first surface structure; and

wherein the at least one light-emitting element arranged within the second space is in contact with fluid surrounding the lighting device.

2. A lighting device according to claim 1 , wherein the second space is fluidly connected to the exterior of the lighting device by means of at least two ports through the base.

3. A lighting device according to claim 2 , wherein at least a portion of the second space extends substantially along a longitudinal axis of the lighting device.

4. A lighting device according to claim 3 , wherein the longitudinal axis is an axis of rotational symmetry of the lighting device.

5. A lighting device according to claim 1 , comprising at least two separately arranged second at least in part light-transmissive surface structures at least in part delimiting at least two separately arranged second spaces, each of which second surface structures is partly enclosed by the first surface structure, wherein each of the second spaces is fluidly connected to the exterior of the lighting device through the base.

6. A lighting device according to claim 1 , wherein the first surface structure comprises an outer light-transmissive enclosure defining an interface between the first space and the exterior of the lighting device.

7. A lighting device according to claim 6 , wherein the first surface structure comprises at least one light-scattering element configured to scatter light incident thereon.

8. A lighting device according to claim 1 , wherein the first surface structure is bulb-shaped or tube-shaped.

9. A lighting device according to claim 1 , wherein the at least one second surface structure comprises an inner light-transmissive enclosure defining an interface between the at least one second space and the first space.

10. A lighting device according to claim 1 , wherein the at least one second surface structure is bulb-shaped or tube-shaped.

11. A lighting device according to claim 1 , wherein the at least one second surface structure comprises at least one light-scattering element configured to scatter light incident thereon.

12. A lighting device according to claim 1 , wherein the at least one second surface structure comprises at least one wavelength-converting element configured to change wavelength of light incident thereon.

13. A lighting device according to claim 1 , wherein the thermally conductive fluid in the first space comprises a gas including helium and/or hydrogen.

14. A lighting device according to claim 1 , wherein the thermally conductive interface comprises at least one carrier configured to support the at least one light-emitting element.

15. A lighting device according to claim 1 , further comprising:

a fluid passage in fluid communication with the first space, the fluid passage including a fluid inlet configured to selectively fluidly connect the first space with a source of thermally conductive fluid.

16. The lighting device of claim 1 , wherein the at least one second space is fluidly connected to the exterior of the lighting device by way of one or more ports that are exclusively disposed in the base.

17. A method comprising:

providing a base for connection to a socket; and

mounting, to the base, a first at least in part light-transmissive surface structure at least in part delimiting a fluidly sealed, closed first space which includes a thermally conductive fluid therein;

wherein as a consequence of the mounting, at least one second at least in part light-transmissive surface structure is contained entirely within the first surface structure and the base, the second transmissive surface structure defining at least one second space which is fluidly connected to the exterior of the lighting device through the base, wherein the at least one second surface structure comprises a thermally conductive interface between the second space and the first space, the thermally conductive interface being coupled to at least one light-emitting element arranged within the second space and configured to emit light such that at least a portion of the emitted light passes through the at least one second surface structure and subsequently through the first surface structure;

wherein the at least one second surface structure has a closed first end and a second, opposite end adjacent the base that fluidly couples the second space to the exterior of the lighting device through the base; and

wherein the at least one light-emitting element arranged within the second space is in contact with fluid surrounding the lighting device.