Lighting device

1. A lighting device comprising a lighting unit configured to emit light and a control unit configured to control the light emitted by the lighting unit, wherein the control unit is configured to change the intensity of the light emitted by the lighting unit at least from a high setting via a mid setting to a low setting and/or vice versa, wherein the intensity of the high setting is greater than the intensity of the mid setting, wherein the intensity of the mid setting is greater than the intensity of the low setting, and wherein the low setting and the high setting each gives a higher color temperature of the light emitted by the lighting unit than the mid setting, and wherein the color temperature of the low setting is greater than the color temperature of the high setting.

2. A lighting device according to claim 1 , wherein the control unit is operable to simultaneously and gradually change the intensity and color temperature of the light emitted by the lighting unit between said three settings.

3. A lighting device according to claim 2 , wherein the control unit is configured to stop decreasing and start increasing the color temperature of the light emitted by the lighting unit, while changing the intensity, at a breakpoint lumen output of the lighting unit in the range of 50-100 lm, preferably in the range of 50-80 lm, and more preferably in the range of 50-70 lm.

4. A lighting device according to claim 2 , wherein the gradual change in color temperature of the light emitted by the lighting unit follows the black body line.

5. A lighting device according to claim 1 , wherein the control unit comprises a user interface including input means configured to allow a user to simultaneously and gradually change the intensity and color temperature of the light emitted by the lighting unit from the high setting to the mid setting and further to the low setting and/or vice versa.

6. A lighting device according to claim 1 , wherein the high setting has a color temperature above 2700K, preferably above 3000K, and more preferably above 3500K, wherein the mid setting has a color temperature below 2700K, preferably below 2600K, and more preferably below 2500K, and wherein the low setting has a color temperature above 2700K, preferably above 3000K, and more preferably above 3500K.

7. A lighting device according to claim 1 , wherein the low setting has a color temperature in the range from 3900 to 4300K.

8. A lighting device according to claim 1 , wherein the light emitted by the lighting unit in the high setting has a different spectrum than the light emitted by the lighting unit in the low setting.

9. A lighting device according to claim 8 , wherein the lighting unit comprises at least one of:

at least two selectively activable blue light sources adapted to emit blue light with mutually different wavelength peaks; and

at least two selectively activable red light sources adapted to emit red light with mutually different wavelength peaks.

10. A lighting device according to claim 1 , wherein the lighting unit comprises a first phosphor converted light emitting diode adapted to emit white light of a first color temperature and a second phosphor converted light emitting diode adapted to emit white light of a second color temperature which is different than the first color temperature.

11. A lighting device according to claim 1 , wherein the control unit is configured to adjust the intensity and color temperature of the low setting based on data of the lunar cycles of the Moon.

12. A lighting apparatus comprising at least one lighting device according to claim 1 .

13. A lighting apparatus according to claim 12 , further comprising a light exit window or surface, wherein the control unit of each lighting device is configured to stop decreasing and start increasing the color temperature of the light emitted by the lighting unit, while changing the intensity, at an intensity at the light exit window or surface below 0.5 lm/cm 2 , preferably below 0.4 lm/cm 2 , and more preferably below 0.3 lm/cm 2 .

14. A method of controlling light emitted by a lighting unit, which method comprises:

changing the intensity of the light emitted by the lighting unit at least from a high setting via a mid setting to a low setting and/or vice versa, wherein the intensity of the high setting is greater than the intensity of the mid setting, wherein the intensity of the mid setting is greater than the intensity of the low setting, and wherein the low setting and the high setting each gives a higher color temperature of the light emitted by the lighting unit than the mid setting, and wherein the color temperature of the low setting is greater than the color temperature of the high setting.