Light emitting device including variable transmission film to control intensity and pattern

A lamp comprising:

• a variable transmissive film including,
• a first light-transmissive electrode,
• a second light-transmissive electrode, and
• an encapsulated bistable electrophoretic dispersion containing a plurality of electrically charged particles and a fluid, wherein the encapsulated bistable electrophoretic dispersion is disposed between the first light-transmissive electrode and the second light-transmissive electrode,
• wherein the electrically charged particles move toward the first light-transmissive electrode or the second light-transmissive electrode when an electric field is provided between the first light-transmissive electrode and the second light-transmissive electrode,
• wherein the encapsulated bistable electrophoretic dispersion is capable of being electrically switched by the electric field between an open, light-transmissive state and a dispersed, light-diffusing state, and
• wherein, after being switched, the encapsulated bistable electrophoretic dispersion maintains the open, light-transmissive state or the dispersed, light-diffusing state without the electric field being provided for a length of time at least four times as long as the duration of the electric field required to switch the encapsulated bistable electrophoretic dispersion between the open, light-transmissive state and the dispersed, light-diffusing state;
• a light source arranged to transmit light through the variable transmissive film;
• and
• a controller to modify the electric field provided between the first light-transmissive electrode and the second light-transmissive electrode.