Lighting device with dynamic light effects

1. A lighting device, comprising:

a housing;

one or more visible-light sources for generating visible light arranged in the housing;

one or more UV-light sources for generating UV-light arranged in the housing;

a light exit window defined in the housing and positioned to allow transmission of the visible light;

a photochromic layer positioned upstream of the light exit window and downstream of the one or more visible-light sources, said photochromic layer comprising at least one area comprising UV-photochromic material having a first color state and a second color state, wherein the photochromic layer comprises at least two areas comprising different UV-photochromic materials having different recovery times;

a control unit connected to the one or more UV-light sources for controlling the one or more UV-light sources, wherein the UV-light sources are arranged to illuminate the photochromic layer; and

a first UV-filter arranged downstream of the light exit window.

2. The lighting device according to claim 1 comprising two or more UV-light sources, each of the two or more UV-light sources being arranged to expose different areas of the photochromic layer during operation.

3. The lighting device according to claim 2 , wherein the control unit is arranged to control the two or more UV-light sources independently of each other.

4. The lighting device according to claim 1 , wherein the photochromic material is applied to an inner side of the light exit window.

5. The lighting device according to claim 1 , further comprising a second UV-filter provided downstream of the one or more UV-light sources and upstream of the photochromic material, wherein the UV-filter has a predetermined recovery time.

6. The lighting device according to claim 5 , further comprising an IR-light source for generating IR-light, wherein the second UV-filter comprises a thermoscattering material.

7. The lighting device according to claim 1 , wherein the control unit is configured to generate PWM signals to control the UV-light sources for effectuate the transition from the first color state to the second color state.

8. The lighting device according to claim 1 , wherein the control unit is configured to control the intensity of the color of the UV-photochromic material.

9. The lighting device according to claim 1 , wherein the UV-light source is configured to generate a spot of UV-light on the photochromic material, and wherein the lighting device further comprises a beam controller for guiding the spot of UV-light across the photochromic material.

10. A lighting device, comprising:

a housing;

one or more visible-light sources for generating visible light arranged in the housing;

one or more UV-light sources for generating UV-light arranged in the housing;

a light exit window defined in the housing and positioned to allow transmission of the visible light;

a photochromic layer positioned upstream of the light exit window and downstream of the one or more visible-light sources, said photochromic layer comprising at least one area comprising UV-photochromic material having a first color state and a second color state;

a control unit connected to the one or more UV-light sources for controlling the one or more UV-light sources, wherein the UV-light sources are arranged to illuminate the photochromic layer;

a first UV-filter arranged downstream of the light exit window; and

a second UV-filter provided downstream of the one or more UV-light sources and upstream of the photochromic material, wherein the UV-filter has a predetermined recovery time.

11. The lighting device according to claim 10 , further comprising an IR-light source for generating IR-light, wherein the second UV-filter comprises a thermoscattering material.

12. The lighting device according to claim 10 , wherein at least one of the one or more UV-light sources is configured to generate a spot of UV-light on the photochromic material, and wherein the lighting device further comprises a beam controller for guiding the spot of UV-light across the photochromic material.

13. The lighting device according to claim 10 , wherein the control unit is configured to generate PWM signals to control the UV-light sources for effectuate the transition from the first color state to the second color state.

14. A lighting device, comprising:

a housing;

one or more visible-light sources for generating visible light arranged in the housing;

one or more UV-light sources for generating UV-light arranged in the housing;

a light exit window defined in the housing and positioned to allow transmission of the visible light;

a photochromic layer positioned upstream of the light exit window and downstream of the one or more visible-light sources, said photochromic layer comprising at least one area comprising UV-photochromic material having a first color state and a second color state;

a control unit connected to the one or more UV-light sources for controlling the one or more UV-light sources, wherein the control unit is configured to generate PWM signals to control the UV-light sources for effectuate the transition from the first color state to the second color state, and wherein the UV-light sources are arranged to illuminate the photochromic layer; and

a first UV-filter arranged downstream of the light exit window.