Color tunable light source

• US 7,703,943 B2
• Filed: 05/07/2007
• Issued: 04/27/2010
• Est. Priority Date: 05/07/2007
• Status: Active Grant

• Current Assignee: Intematix Corporation
• Original Assignee: Intematix Corporation
• Inventors: Collier, Ian, Dong, Yi, Li, Yi-Qun, Xu, Xiaofeng
• Primary Examiner(s): Choi; Jacob Y
• Application Number:
  US11/800,976
• Publication Number:
  US 20080278927A1
• Time in Patent Office: 1,086 Days
• Field of Search: 362/612, 362/613, 362/631, 362/561, 362/800, 362/227, 362/230, 362/231, 362/235, 362/317, 362/321, 362/318, 385/129, 385/130, 359/237, 359/298, 359/315, 359/319
• US Class Current: 362/231
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: H05B 45/20 Controlling the colour of the light

Abstract

A color tunable light source comprises: a first light emitting diode (LED) arrangement operable to emit light of a first color and a second LED arrangement operable to emit light of a second color, the combined light output comprising the output of the source. One or both LED arrangements comprises a phosphor provided remote to an associated LED operable to generate excitation energy of a selected wavelength range and to irradiate the phosphor such that it emits light of a different color wherein light emitted by the LED arrangement comprises the combined light from the LED and phosphor and control means operable to control the color by controlling the relative light outputs of the two LED arrangements. The color can be controlled by controlling the relative magnitude of the drive currents of the LEDs or by controlling a duty cycle of PWM drive current.

Claims

1. A color tunable light source comprising:

a first light emitting diode arrangement operable to emit light of a first color;

a second light emitting diode arrangement operable to emit light of a second color, the light emitting diode arrangements being configured such that their combined light output comprises the output of the source, wherein the first light emitting diode arrangement comprises a phosphor provided remote to an associated first light emitting diode that is operable to generate excitation light of a selected wavelength range and to irradiate the phosphor such that the phosphor emits light of a different color, wherein light emitted by the first light emitting diode arrangement comprises the combined light from the first light emitting diode and the light emitted from the phosphor; and

control means operable to control the color of light emitted by the source by controlling the ratio of intensity of light emitted by the first and second light emitting diode arrangements, the control means comprising a pulse width modulated power supply operable to generate a pulse width modulated drive current and wherein the first and second light emitting diode arrangements are operable on opposite phases of the pulse width modulated drive current and the color of light emitted by the source is controllable by a duty cycle of the drive current.

2. A color tunable light source comprising:

a first light emitting diode arrangement operable to emit light of a first color;

a second light emitting diode arrangement operable to emit light of a second color, the light emitting diode arrangements being configured such that their combined light output comprises the output of the source, wherein the light emitting diode arrangements comprise a respective phosphor provided remote to a light emitting diode that is operable to generate excitation light of a selected wavelength range and to irradiate the phosphors such that each emits light of a different color and wherein light emitted by each light emitting diode arrangement comprises the combined light from the light emitting diode and the light emitted from the phosphor;

a light controller associated with each phosphor; and

control means operable to control the color of light emitted by the source by controlling the light controllers to control the ratio of irradiation intensity of the phosphors, wherein the control means comprises a pulse width modulated power supply operable to generate a pulse width modulated drive voltage and the light controllers are operable on opposite phases of the pulse width modulated drive voltage and the color of light emitted by the source is tunable by controlling a duty cycle of the drive voltage.

3. A color tunable light source comprising:

a first light emitting diode arrangement operable to emit light of a first color and comprising a phosphor provided remote to an associated first blue/UV light emitting diode operable to generate excitation energy of a selected wavelength range and to irradiate the phosphor such that the phosphor emits light of a different color wherein light emitted by the first light emitting diode arrangement comprises the combined light from the first light emitting diode and the light emitted from the phosphor;

a second light emitting diode arrangement operable to emit light of a second color and comprising a respective phosphor provided remote to an associated second blue/UV light emitting diode operable to generate excitation energy of a selected wavelength range and to irradiate the phosphor such that it emits light of a different color wherein the light emitted by the second light emitting diode arrangement comprises the combined light from the second light emitting diode and the light emitted from the phosphor, wherein the light emitting diode arrangements are configured such that their combined light output comprises the output of the source; and

control means operable to control the color of light emitted by the source by controlling the ratio of intensity of light emitted by the first and second light emitting diode arrangements, the control means comprising a pulse width modulated power supply operable to generate a pulse width modulated drive current and wherein the first and second light emitting diodes are operable on opposite phases of the pulse width modulated drive current and the color of light emitted by the source is controllable by a duty cycle of the drive current.