Generating a spotlight
An example system includes a light source coated with a phosphor layer, a laser emitter to output a laser beam, and a controller to control a direction of the laser beam so that the laser beam hits a location on the phosphor layer. The laser beam excites the location on the phosphor layer to produce a spotlight at the location.
1. A system comprising:
a light source coated with a phosphor layer;
a laser emitter to output a laser beam;
a controller to control a direction of the laser beam so that the laser beam hits a location on the phosphor layer, the laser beam exciting the location on the phosphor layer to produce a beam of light at the location; and
a lens having a first surface to receive the beam of light and a second surface that is convex to output the beam of light as a spotlight, wherein the light source comprises light emitting devices coated with the phosphor layer, the light emitting devices being configured to produce light without the laser beam exciting the location on the phosphor layer.
2. The system of claim 1 , wherein the spotlight has a luminous intensity that exceeds a luminous intensity of light produced by the light source at the location absent the laser beam exciting the location.
3. The system of claim 1 , wherein the controller is configured to control the direction of the laser beam so that the laser beam hits the location on the phosphor layer when the light source is activated.
4. The system of claim 1 , wherein the controller is configured to control the direction of the laser beam so that the laser beam hits the location on the phosphor layer when the light source is not activated.
5. The system of claim 1 , further comprising:
a steerable device to direct the laser beam to the phosphor layer.
6. The system of claim 5 , wherein the steerable device comprises a micro-electromechanical device comprising a mirror that is movable.
7. The system of claim 5 , further comprising:
a mirror to receive the laser beam from the steerable device and to reflect the laser beam to the phosphor layer, the steerable device being controllable by the controller to move the laser beam to different points on the mirror and therefore to different locations on the phosphor layer; and
one or more optical elements in an optical path between the mirror and the steerable device, the one or more optical elements comprising a lens to focus the laser beam onto the phosphor layer.
8. The system of claim 1 , wherein the laser emitter comprises:
a laser diode; and
a collimating lens;
wherein the laser diode is configured to emit blue light and the phosphor layer is configured to convert the blue light to white light.
9. The system of claim 1 , wherein the spotlight has a luminous flux of at least 250 Lumens and the laser beam has an optical power of at least 1 Watt.
10. The system of claim 1 , wherein the phosphor layer comprises cerium-doped yttrium aluminum garnet.
11. The system of claim 1 , wherein the phosphor layer comprises a europium doped nitridoaluminate.
12. The system of claim 1 , wherein the light source comprises a gallium-nitride (GaN) based light-emitting diode (LED) device.
13. The system of claim 1 , wherein the laser emitter is movable; and
wherein movement of the laser emitter is controllable by the controller to control the direction of the laser beam so that the laser beam hits the location on the phosphor layer.
14. The system of claim 1 , wherein the system comprises a vehicle; and
wherein the light source is part of a headlight for the vehicle.
15. The system of claim 14 , wherein the controller is configured to control the direction of the laser beam based on an external illumination in an environment in which the vehicle is located.
16. The system of claim 14 , wherein the controller is configured to control the direction of the laser beam based on an object in a vicinity of the vehicle.
17. The system of claim 14 , wherein the controller is configured to control a direction of the laser beam based on an operator of the vehicle.
18. The system of claim 1 , wherein the light emitting devices comprise light emitting diodes (LEDs).
19. The system of claim 18 , wherein the spotlight has a luminous intensity that exceeds a luminous intensity of light produced by the LEDs without the laser beam exciting the location on the phosphor layer.
20. The system of claim 1 , wherein the first surface is flat.
21. The system of claim 1 , wherein the second surface reduces dispersion of the light beam.