Illumination device

• US 7,334,917 B2
• Filed: 09/29/2005
• Issued: 02/26/2008
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Laski, Joseph John
• Primary Examiner(s): Sember; Thomas M.
• Application Number:
  US11/238,247
• Publication Number:
  US 20060082333A1
• Time in Patent Office: 880 Days
• Field of Search: 362/249, 362/252, 362/230, 362/231, 362/800, 362/293, 362/251, 315/185.R, 315/193, 315/246, 315/287, 315/307, 315/DIG.4, 315/308
• US Class Current: 362/231
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/325 Pulse-width modulation [PWM]

Abstract

An illumination device comprising at least four luminous units (1, 2), the light emitted by at least two of the four luminous units (1, 2) being suitable for being mixed to form white light. Moreover, an apparatus (3) for dimming at least one of the four luminous units (1, 2) is provided. White light having a desired color temperature (CCT) and a high color rendering index can be generated by means of the illumination device.

Claims

1. An illumination device, comprising:

a first light-emitting diode module comprising at least one light-emitting diode that emits light in the red spectral range, at least one light-emitting diode that emits light in the green spectral range, and at least one light-emitting diode that emits light in the blue spectral range;

a second light-emitting diode module comprising at least one light-emitting diode that emits light in the yellow spectral range;

an apparatus configured to generate pulse-width-modulated signals for driving at least one portion of the light-emitting diodes; and

a control apparatus configured to set at least one predefined correlated color temperature (CCT) of the light emitted by the illumination device.

2. The illumination device as claimed in claim 1, wherein the control apparatus comprises switches, and wherein each switch is assigned a color temperature of the white light emitted by the illumination device in such a way that as a result of one of the switches being closed and the remaining switches being opened, white light having the color temperature assigned to the switch is emitted by the illumination device.

3. The illumination device as claimed in claim 1, wherein the control apparatus comprises a network of three times eight series circuits, each series circuit including a potentiometer and a diode connected in series with the potentiometer.

4. The illumination device as claimed in claim 1, wherein depending on the state of the switches of the control apparatus, voltages are present at control inputs of the apparatus and the brightness of at least one portion of the light-emitting diodes of the light-emitting diode modules is dependent on said voltages.

5. The illumination device as claimed in claim 4, wherein the apparatus is configured to generate pulse-width-modulated signals for the blue, yellow, and red light-emitting diodes of the light-emitting diode module and the green light-emitting diodes emit light with maximum intensity independently of the position of the switches of the control apparatus.

6. The illumination device as claimed in claim 4, wherein the green light-emitting diodes of the first light-emitting diode module are directly connected to the current supply.

7. The illumination device as claimed in claim 1, wherein the control apparatus is configured to select at least between the following correlated color temperatures (CCT):

6500 K, 5500 K, 5000 K, 4100 K, 3500 K, 3000 K, 2800 K, 2500 K.

8. The illumination device as claimed in claim 1, wherein each light-emitting diode module comprises ten or fewer light-emitting diodes of the same color.

9. The illumination device as claimed in claim 1, wherein the first light-emitting diode module comprises at least one light-emitting diode that emits light with a central wavelength of between 455 nm and 485 nm, at least one light-emitting diode that emits light with a central wavelength of between 512 nm and 538 nm, and at least one light-emitting diode that emits light with a central wavelength of between 608 nm and 626 nm, and wherein the second light-emitting diode module comprises at least one light-emitting diode that emits light with a central wavelength between 580 nm and 594 nm.