Lighting apparatus and method for controlling brightness and color location thereof
View Patent ↗A lighting apparatus emitting polychromatic light comprising light of at least two light-channels with different colors, wherein each light-channel is controlled by one modified pulse-width-modulated signal (modified PWM-signal), and each modified PWM-signal results from the modulation of one color-pulse-width-modulated signal (color-PWM-signal) with an intensity-pulse-width-modulated signal (intensity-PWM-signal) in order to control the brightness and color location of the polychromatic light.
1. A method for controlling brightness and color location of a lighting apparatus emitting polychromatic light comprising light of at least two light-channels with different colors, wherein:
the method comprises the step of controlling each light-channel by one modified pulse-width-modulated signal (modified PWM-signal), and
each modified PWM-signal results from the modulation of one color-pulse-width-modulated signal (color-PWM-signal) with an intensity-pulse-width-modulated signal (intensity-PWM-signal).
2. The method of claim 1 , wherein
the color-PWM-signals are modulated with the same intensity-PWM-signal.
3. The method of claim 1 , wherein
the color-PWM-signals are modulated with the intensity-PWM-signal by multiplying.
4. The method of claim 1 , wherein
the polychromatic light comprises the light of one red, one green and one blue light-channel.
5. The method of claim 1 , wherein
the polychromatic light comprises the light of one yellow, one cyan and one magenta light-channel.
6. The method of claim 1 , wherein
the intensity-PWM-signal has a fundamental period shorter than a fundamental period of the color-PWM signal.
7. The method of claim 1 , wherein
the intensity-PWM-signal has a fundamental period shorter than a fundamental period of the color-PWM signal by at least one order of magnitude.
8. The method of claim 1 , wherein
the intensity-PWM-signal has a fundamental period longer than a fundamental period of the color-PWM signal.
9. The method of claim 1 , wherein
the intensity-PWM-signal has a fundamental period longer than a fundamental period of the color-PWM signal by at least one order of magnitude.
10. The method of claim 1 , wherein
the polychromatic light has a desired color location within the CIE-diagram.
11. The method of claim 9 , wherein
the desired color location is within the white region of the CIE-diagram.
12. Lighting apparatus emitting polychromatic light comprising at least light of two light-channels with different colors, wherein brightness and color location are controlled using the method of claim 1 .
13. Lighting apparatus of claim 12 , wherein
the light of the light-channels is emitted by semiconductor light emitting diodes (LEDs), organic light emitting diodes (OLEDs), laser diodes and/or electroluminescent foils.
14. Apparatus for back-lighting an LCD-display with the lighting apparatus of claim 12 .