Optoelectronic device that emits mixed light

• US 9,398,664 B2
• Filed: 11/13/2009
• Issued: 07/19/2016
• Est. Priority Date: 11/14/2008
• Status: Active Grant

• Current Assignee: OSRAM OLED GMBH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Wirth, Ralph
• Primary Examiner(s): Kim, Jay C
• Application Number:
  US13/128,472
• Publication Number:
  US 20110291129A1
• Time in Patent Office: 2,440 Days
• Field of Search: 257/88, 257/89, 257/90, 257/94, 257/96
• US Class Current: 1/1
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05B 31/50 specially adapted for ac
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/28 using temperature feedback

Abstract

An optoelectronic device includes a first semiconductor light source having a first light-emitting diode; a second semiconductor light source having a second light-emitting diode; and a resistance element having a temperature-dependent electrical resistance, wherein a first wavelength and/or a first intensity of light emitted by the first semiconductor light source have/has a first temperature dependence, and the second wavelength range and/or the second intensity of the fight emitted by the second semiconductor light source have/has a second temperature dependence different from the first temperature dependence, the resistance element and the first semiconductor light source form a series circuit, and the series circuit and the second semiconductor light source form a parallel circuit.

Claims

1. An optoelectronic device that emits mixed light comprising light in a first and a second wavelength range, comprising:

a first semiconductor light source having a first light-emitting diode, which during operation emits light in the first wavelength range with a first intensity;

a second semiconductor light source having a second light-emitting diode, which during operation emits light in the second wavelength range with a second intensity, wherein the first and second wavelength ranges are different from one another; and

a resistance element that is a thermistor which has a temperature-dependent electrical resistance with either a positive or a negative temperature coefficient, wherein

the first wavelength range and the first intensity of the light emitted by the first semiconductor light source have a first and second temperature dependence, respectively; and

the second wavelength range and the second intensity of the light emitted by the second semiconductor light source have a third and fourth temperature dependence, respectively, wherein the first temperature dependence is different from the third temperature dependence and/or the second temperature dependence is different from the fourth temperature dependence;

the resistance element and the first semiconductor light source form a series circuit; and

the series circuit and the second semiconductor light source form a parallel circuit;

wherein the first light-emitting diode emits blue primary light and the first semiconductor light source comprises a wavelength conversion substance which converts part of the blue primary light into green, yellow or yellow-green secondary light such that the first wavelength range brings about a greenish-white to cold white color impression,

the second light-emitting diode comprises InGaAlP, which emits light in a red wavelength range, and

the first light-emitting diode and the second light-emitting diode are different, and

wherein one branch of the parallel circuit comprises the thermistor and the other branch of the parallel circuit does not comprise any thermistor.

2. The device according to claim 1, wherein

the first temperature dependence is less than the third temperature dependence;

and

the resistance element is a resistance element having a positive temperature coefficient.

3. The device according to claim 2, wherein the resistance element comprises platinum or silicon.

4. The device according to claim 1, wherein

the first temperature dependence is greater than the third temperature dependence;

and

the resistance element is a resistance element having a negative temperature coefficient.

5. The device according to claim 1, wherein electrical resistance of the resistance element varies continuously in a temperature range of −

40°

C. to 125°

C.

6. The device according to claim 1, further comprising at least one electronic component that sets the mixed light at a predetermined temperature, wherein the at least one electronic component is a fixed resistor, a variable resistor or a transistor.

7. The device according to claim 1, wherein

the parallel circuit is connected in series with at least one third semiconductor light source comprising

one or more further light-emitting diodes, wherein the one or more further light-emitting diodes have a structure substantially identical to the first light-emitting diode of the first semiconductor light source.

8. The device according to claim 7, wherein the at least one third semiconductor light source has at least one electronic component that sets a relative intensity ratio of the at least one third semiconductor light source and the parallel circuit at a predetermined temperature.

9. The device according to claim 8, wherein

the at least one third semiconductor light source has at least one third light-emitting diode, which during operation emits light in a third wavelength range, which is different from the first wavelength range;

and

the at least one electronic component sets a relative intensity ratio of the one or more further light-emitting diodes in the at least one third semiconductor light source and the at least one third light-emitting diode in the at least one third semiconductor light source at a predetermined temperature.

10. The device according to claim 1, wherein the resistance element is in thermal contact at least with the first semiconductor light source via a heat conductor.

11. The device according to claim 1, wherein the first semiconductor light source is applied directly on the resistance element.

12. The device according to claim 1, wherein the resistance element is a carrier substrate for the first light-emitting diode.

13. The device according to claim 1, wherein the optoelectronic device further comprises a housing containing the first and second semiconductor light sources and the resistance element.

14. The device according to claim 1, further comprising a first housing with the first semiconductor light source and the resistance element and a second housing with the second semiconductor light source, wherein the first and second housings are in thermal contact.

15. The device according to claim 1, wherein the mixed light in a temperature range of 0°

C. to 100°

C. has a temperature-dependent color locus shift by an average color locus, which shift runs along a major axis of a MacAdams ellipse around the average color locus.

16. The device according to claim 1, wherein the mixed light has a temperature dependence with regard to its color locus stabilized by interconnection of the resistance element with the first and second semiconductor light sources.

17. The device according to claim 1, wherein the first light-emitting diode comprises InGaN, which emits light in a blue wavelength range.

18. An optoelectronic device that emits mixed light comprising light in a first and a second wavelength range, comprising:

a first semiconductor light source having a first light-emitting diode, which during operation emits light in the first wavelength range with a first intensity;

a second semiconductor light source having a second light-emitting diode, which during operation emits light in the second wavelength range with a second intensity, wherein the first and second wavelength ranges are different from one another; and

a resistance element that is a thermistor having a temperature-dependent electrical resistance with either a positive or a negative temperature coefficient, the resistance element being in thermal contact and interconnected in series with the first light source so that voltage dropped across the first semiconductor light source and current flowing through the first semiconductor light source are influenced directly by the resistance element, wherein

the first wavelength range and the first intensity of the light emitted by the first semiconductor light source have a first and second temperature dependence, respectively; and

the second wavelength range and the second intensity of the light emitted by the second semiconductor light source have a third and fourth temperature dependence, respectively, wherein the first temperature dependence is different from the third temperature dependence and/or the second temperature dependence is different from the fourth temperature dependence;

the resistance element and the first semiconductor light source form a series circuit;

the series circuit and the second semiconductor light source form a parallel circuit,

wherein the first light-emitting diode emits blue primary light and the first semiconductor light source comprises a wavelength conversion substance which converts part of the blue primary light into green, yellow or yellow-green secondary light such that the first wavelength range brings about a greenish-white to cold white color impression, and the second light-emitting diode comprises InGaAlP, which emits light in a red wavelength range, and

the first light-emitting diode and the second light-emitting diode are different, and

wherein one branch of the parallel circuit comprises the thermistor and the other branch of the parallel circuit does not comprise any thermistor.

19. An optoelectronic device that emits mixed light comprising light in a first and a second wavelength range, comprising:

a first semiconductor light source having a first light-emitting diode, which during operation emits light in the first wavelength range with a first intensity;

a second semiconductor light source having a second light-emitting diode, which during operation emits light in the second wavelength range with a second intensity, wherein the first and second wavelength ranges are different from one another; and

a resistance element that is a thermistor which has a temperature-dependent electrical resistance with either a positive or a negative temperature coefficient, wherein

the first wavelength range and the first intensity of the light emitted by the first semiconductor light source have a first and second temperature dependence, respectively; and

the second wavelength range and the second intensity of the light emitted by the second semiconductor light source have a third and fourth temperature dependence, respectively, wherein the first temperature dependence is different from the third temperature dependence and/or the second temperature dependence is different from the fourth temperature dependence;

the resistance element and the first semiconductor light source form a series circuit; and

the series circuit and the second semiconductor light source form a parallel circuit;

wherein the first light-emitting diode emits blue primary light and the first semiconductor light source comprises a wavelength conversion substance which converts part of the blue primary light into green, yellow or yellow-green secondary light such that the first wavelength range brings about a greenish-white to cold white color impression, and the second light-emitting diode comprises InGaAlP, which emits light in a red wavelength range, and

wherein the thermistor is present only in the branch of the parallel circuit comprising the first light-emitting diode and the other branch of the parallel circuit does not comprise any thermistor, and

the first light-emitting diode and the second light-emitting diode are different.