PULSE-CONTROLLED LIGHT EMITTING DIODE SOURCE

• US 20090140660A1
• Filed: 11/21/2008
• Published: 06/04/2009
• Est. Priority Date: 02/04/1998
• Status: Abandoned Application

• Current Assignee: Round Rock Research LLC
• Original Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Inventors: Waligorski, Grzegorz M., Fossum, Eric R.
• Application Number:
  US12/275,937
• Publication Number:
  US 20090140660A1
• Time in Patent Office: Days
• US Class Current: 315/158
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G01J 1/08 Arrangements of light sources specially adapted for photometry standard sources, also using luminescent or radioactive material

Abstract

A light-emitting diode array is driven by a digital control. The digital control modulates the pulse width of pulses applied to the light-emitting diode. The intensity of the output is controlled by controlling the width of pulses applied to the light-emitting diode. Since light-emitting diodes have very low inertial energy, this system can be rapidly turned on and turned off. The output is integrated to produce a uniform output.

Claims

1-12. -12. (canceled)

13. A controllable light source, comprising:

at least three light emitting diodes contained in a single package, each having a different characteristic of output light

wherein the three light emitting diodes are arranged within a row, the row comprising a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs, and wherein the light integrator is configured to diffuse light from the row;

a controller for the light emitting diodes that produces a pulse-width modulated control pulse having an on state and an off state;

a brightness controller, controlling said controller to produce longer on states for higher brightness, and shorter on states for lower brightness; and

a light integrator having the light emitting diodes disposed therein to integrate light output from the light emitting diodes, wherein the light integrator includes an output port from which the integrated light is output.

14. The light source of claim 13, wherein the red, green, and blue LEDs are interspersed with one another within the row to facilitate color mixing.

15. The light source of claim 14, further comprising:

a circuit configured to collectively control a brightness of the three light emitting diodes together;

wherein the brightness controller is configured to separately adjust a first signal, a second signal, and a third signal, wherein the first signal is coupled to control a brightness of the plurality of red LEDs, the second signal is coupled to control a brightness of the plurality of green LEDs, and the third signal is coupled to control a brightness of the plurality of blue LEDs.

16. The light source of claim 15, wherein the circuit comprises a first logic configured to combine the first signal with a control signal, a second logic configured to combine the second signal with the control signal, and a third logic configured to combine the third signal with the control signal.

17. The light source of claim 15, further comprising a light detection unit disposed to receive light mixed from the plurality of red, green, and blue LEDs, and configured to indicate an intensity of red light, an intensity of green light, and an intensity of blue light emanating from the red, green, and blue LEDs.

18. The light source of claim 17, wherein the light detection unit is not saturated.

19. The light source of claim 17, further comprising at least one color filter adjacent to the output port and configured to filter light exiting the output port.

20. A method of controlling a light source comprising:

controlling an intensity of a first red LED responsive to a first input signal that controls an intensity of a plurality of red LEDs, including receiving a gating signal at a first input of a first logic circuit and receiving the first input signal at a second input of the first logic circuit and activating and deactivating the red LED in response to a signal at an output of the first logic circuit to thereby control an intensity of the first red LED;

controlling an intensity of a first green LED responsive to a second input signal that controls an intensity of a plurality of green LEDs, including receiving the gating signal at a first input of a second logic_circuit and receiving the second input signal at a second input of the second logic_circuit and activating and deactivating the green LED in response to a signal at an output of the second logic_circuit to thereby control an intensity of the first green LED;

controlling an intensity of a first blue LED responsive to a third input signal that controls an intensity of a plurality of blue LEDs, including receiving the gating signal at a first input of a third logic circuit and receiving the third input signal at a second input of the third logic circuit and activating and deactivating the blue LED in response to a signal at an output of the third logic circuit to thereby control an intensity of the first blue LED; and

diffusing light from the plurality of red, green, and blue LEDs,

wherein the first red LED, the first green LED, and the first blue LED are formed in a single package.

21. The method of claim 20, further comprising emitting the light from the plurality of red, green, and blue LEDs primarily away from the output port.

22. The method of claim 20, further comprising providing the gating signal, the first input signal, the second input signal, and the third input signal from a personal computer.

23. The method of claim 20, further comprising receiving the light from the plurality_of red, green, and blue LEDs at an array of pixels.

24. The method of claim 23, further comprising

receiving the light from the plurality of red, green, and blue LEDs at a light detection device.

25. The method of claim 23, further comprising filtering the light from the plurality of red, green, and blue LEDs through a color filter.

26. The method of claim 20, further comprising filtering the light from the plurality of red, green, and blue LEDs through red, green, and blue color filters.

27. A system comprising:

a light source comprising a first LED, a second LED, and a third LED, disposed in a single package;

a power supply;

a driver circuit configured to couple the power supply to the light source and to adjust an intensity of light from the light source by providing a first duty cycle of a first waveform configured to drive the first LED, a second duty cycle of a second waveform configured to drive the second LED, and a third duty cycle of a third waveform configured to drive the third LED;

a first control circuit coupled to the driver circuit and configured to provide a first signal to control the first duty cycle, a second signal to control the second duty cycle, and a third signal to control the third duty cycle, wherein the first, second, and third signals are distinct from each other;

a diffuser to diffuse light from the first, second, and third LEDs to produce a diffused light at an output port; and

at least one color filter adjacent to the output port configured to pass through colored light from the diffused light.

28. The system of claim 27, further comprising:

a red color filter configured to pass through red light from the diffused light;

a green color filter configured to pass through green light from the diffused light; and

a blue color filter configured to pass through blue light from the diffused light.

29. The system of claim 27, wherein the first LED, the second LED, and the third LED have different characteristics of output light.

30. The system of claim 27, further comprising a pixel array disposed to receive light from the light source.

31. The system of claim 30, further comprising:

a second control circuit configured to provide a control signal to control the first, second, and third duty cycles;

a first circuit configured to combine the control signal with the first signal to control the first duty cycle;

a second circuit configured to combine the control signal with the second signal to control the second duty cycle; and

a third circuit configured to combine the control signal with the third signal to control the third duty cycle.

32. The system of claim 31, wherein the the second control circuit is further configured to provide the control signal to control duty cycles of all waveforms configured to drive all LEDs in the light integrator, including the first, second, and third LEDs.