LED lighting device with mint, amber and yellow colored light-emitting diodes

Abstract

Various embodiments may relate to an LED lighting device, including at least one mint-colored light-emitting diode, at least one amber-colored light-emitting diode and at least one yellow light-emitting diode and/or blue light-emitting diode.

Claims

1. An LED lighting device, comprising: a plurality of light-emitting diodes belonging to different wavelength groups, wherein the plurality of light-emitting diodes comprises one or a plurality of sets comprising in each case one mint-colored light-emitting diode, one amber-colored light-emitting diode and a plurality of yellow light-emitting diodes, wherein the yellow light-emitting diodes belong to different wavelength groups, wherein the LED lighting device is designed, at a relatively low temperature, to operate only the yellow light-emitting diode from the wavelength group with the highest dominant wavelength and, as the temperature rises, to switch in progressively the yellow light-emitting diodes from the wavelength groups with the lower dominant wavelengths.

2. The LED lighting device as claimed in claim 1, wherein the number of yellow light-emitting diodes corresponds at least approximately to a number of the mint-colored light-emitting diodes and amber-colored light-emitting diodes.

3. The LED lighting device as claimed in claim 1, wherein the number of yellow light-emitting diodes corresponds at least approximately to one quarter of the light-emitting diodes.

4. The LED lighting device as claimed in claim 3, wherein the number of mint-colored light-emitting diodes and the number of amber-colored light-emitting diodes at least approximately correspond to one another and of them at least approximately every sixth mint-colored light-emitting diode and every third amber-colored light-emitting diode is replaced by a yellow light-emitting diode.

5. The LED lighting device as claimed in claim 1, wherein the LED lighting device is dimmable by reduction of an operating current of the mint-colored light-emitting diodes and of the amber-colored light-emitting diodes.

6. The LED lighting device as claimed in claim 1, wherein the LED lighting device comprises at least one blue light-emitting diode and is designed to switch off the at least one blue light-emitting diode upon a temperature threshold value being reached, wherein the temperature threshold value lies below a typical operating temperature of the at least on blue light-emitting diode.

7. The LED lighting device as claimed in claim 1, wherein the LED lighting device is a retrofit lamp.

8. The LED lighting device as claimed in claim 1, wherein the at least one mint-colored light-emitting diode comprises an InGaN chip, the at least one amber-colored light-emitting diode comprises an InGaAlP chip, and the at least one yellow light-emitting diode comprises an InGaAlP chip.

9. The LED lighting device as claimed in claim 1, wherein all light-emitting diodes comprise LED chips of the same basic type.

10. The LED lighting device as claimed in claim 1, wherein the LED lighting device is or comprises a chip-on-board module.

11. The LED lighting device as claimed in claim 1, wherein the LED lighting device is an incandescent lamp or halogen lamp retrofit lamp.

12. The LED lighting device as claimed in claim 9, wherein the LED chips are INGaN chips.

13. An LED lighting device, comprising: a plurality of light-emitting diodes belonging to different wavelength groups, wherein the plurality of light-emitting diodes comprise at least one mint-colored light-emitting diode, at least one amber-colored light-emitting diode and a plurality of yellow light-emitting diodes, wherein the yellow light-emitting diodes belong to different wavelength groups, wherein the LED lighting device is designed, at a relatively low operating temperature, to operate only the yellow light-emitting diode from the wavelength group with the highest dominant wavelength and, as the operating temperature rises, to switch in progressively the yellow light-emitting diodes from the wavelength groups with the lower dominant wavelengths.

14. The LED lighting device as claimed in claim 13, wherein the operating temperature is junction temperature.

15. An LED lighting device comprising: a plurality of light-emitting diodes belonging to different wavelength groups, wherein the plurality of light-emitting diodes comprise at least one set, each set comprising at least one mint-colored light-emitting diode, at least one amber-colored light-emitting diode and a plurality of yellow light-emitting diodes, wherein the yellow light-emitting diodes belong to different wavelength groups, wherein the LED lighting device is designed, at a relatively low temperature, to operate only the yellow light-emitting diodes from those wavelength groups with the highest dominant wavelength and, as the temperature rises, to switch in progressively the yellow light-emitting diodes from the wavelength groups with those lower dominant wavelengths.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the disclosed embodiments. In the following description, various embodiments described with reference to the following drawings, in which:

(2) FIG. 1 shows an LED lighting device according to the present disclosure in the form of an incandescent lamp retrofit lamp as a sectional illustration in side view; and

(3) FIG. 2 shows the LED lighting device in a plan view of associated light-emitting diodes.

DETAILED DESCRIPTION

(4) The following detailed description refers to the accompanying drawing that show, by way of illustration, specific details and embodiments in which the disclosure may be practiced.

(5) FIG. 1 shows an LED lighting device 11 in the form of an incandescent lamp retrofit lamp as a sectional illustration in side view. The LED lighting device 11 includes a heat sink 12, e.g. composed of aluminum, on which is situated at the rear side an electrical connection 13, e.g. an Edison base or a bipin base (e.g. of the GU type). The heat sink 12 has a driver cavity 14, in which a driver 15 is situated. The driver 15 is electrically connected to the electrical connection 13 and feeds a plurality of light-emitting diodes 16, 17, 18. The light-emitting diodes 16 to 18 are applied on a common ceramic substrate 19 bearing on the front side on the heat sink 12. On the front side, the heat sink 12 additionally carries an opaque envelope 20 arching over the light-emitting diodes 16 to 18.

(6) As shown in FIG. 2 in a section A-A through the envelope 20 that is perpendicular to a longitudinal axis L, the ceramic substrate 19 is embodied in a ring-shaped fashion, and the light-emitting diodes 16 to 18 are distributed thereon in a manner spaced apart uniformly in the circumferential direction.

(7) The light-emitting diodes 16 to 18 include five mint-colored light-emitting diodes 16 which consist of a blue InGaN chip with a green-yellow phosphor. The mint-colored (mixed) light emitted by the light-emitting diodes 16 may also be designated as EQ white. Furthermore, four amber-colored light-emitting diodes 17 in the form of InGaAlP chips and three yellow light-emitting diodes 18, likewise in the form of InGaAlP chips, are present. The five mint-colored light-emitting diodes 16 and the four amber-colored light-emitting diodes 17 form a brilliant mix. At least the three yellow light-emitting diodes 18 belong to different wavelength groups.

(8) When the lighting device 11 is switched on in a cold state (e.g. at room temperature of 25 C.), the five mint-colored light-emitting diodes 16 and the four amber-colored light-emitting diodes 17 generate a mixed light which is shifted into the red in comparison with a warm-white mixed light at a normal operating temperature of approximately 85 C. This shift of the color locus is undesirable, however, in particular since the color locus is at an appreciable distance from the Planckian locus and does not correspond to a color impression of a conventional incandescent lamp to be imitated. In order to improve the color impression at low operating temperatures and to draw the color locus in the direction of the Planckian locus, the light emitted by the yellow light-emitting diodes 18 is used. The opaque envelope supports homogenization of the mixed light passing through it.

(9) As the operating temperature rises, the cumulative color locus of the mint-colored light-emitting diodes 16 and of the amber-colored light-emitting diodes 17 approaches its desired value in the vicinity of the Planckian locus. Their brightness decreases in the process. A brightness of the yellow light-emitting diodes 18 decreases to a particularly great extent, however, such that a proportion constituted by the yellow light in the total mixed light emitted by the LED lighting device 11 is negligibly low at normal operating temperature. Consequently, the temperature-dependent adaptation of the color locus may be achieved even without active control. In particular, the driver 15 may still be configured as a single-channel driver, which makes its construction particularly simple.

(10) It is also possible to make the LED lighting device 11 dimmable. During dimming, the operating temperatures remain in a high range. In order nevertheless to reproduce the property of a conventional incandescent lamp that the color locus shifts from white-yellow at 100% luminous flux to yellow-orange at 10% luminous flux, the driver 15 may be configured such that it reduces (dims) an operating current of the mint-colored light-emitting diodes 16 and of the amber-colored light-emitting diodes 17, while the yellow light-emitting diode(s) is/are operated with an unchanged current. This may lead, for example, to a shift in the color locus from 2550 K to 2150 K. The reduction of the operating current may take place, for example, by a lowering of the current level and/or by a change in a duty ratio in PWM operation.

(11) The driver 15 may also be configured such that it switches off the yellow light-emitting diodes 18 upon the exceeding of a temperature threshold value (e.g. of 75 C.) near the normal operating temperature (e.g. of 85 C.)

(12) While the disclosed embodiments have been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosed embodiments as defined by the appended claims. The scope of the disclosed embodiments is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.

LIST OF REFERENCE SIGNS

(13) 11 LED lighting device 12 heat sink 13 electrical connection 14 driver cavity 15 driver 16 mint-colored light-emitting diode 17 amber-colored light-emitting diode 18 yellow light-emitting diode 19 ceramic substrate 20 envelope L longitudinal axis