We claim ornamental designs for the light bulb heat sink, as shown and described.
FIG. 1 illustrates an isometric perspective view 100 of an isometric perspective view of a light bulb heat sink according to an exemplary embodiment of the present invention.
FIG. 2 illustrates a top orthographic perspective view 200 of a light bulb heat sink according to an exemplary embodiment of the present invention.
FIG. 3 illustrates a bottom orthographic perspective view 300 of a light bulb heat sink according to an exemplary embodiment of the present invention; and,
FIG. 4 illustrates a side orthographic perspective view 400 of a light bulb heat sink according to an exemplary embodiment of the present invention.
The broken line showing of the other bulb portions is included for the purpose of illustrating only and forms no part of the claimed design.