LED illuminant based blinder with LED color mixing for modeling of a color decay and LED module therefor

Abstract

A LED module (24) for a blinder (10) having several LEDs (30) of the color warm white, one LED or several LEDs (30) of the color red, and one LED or several LEDs (30) of the color amber.

Claims

1. An LED module for a blinder comprising several LEDs of the color warm white, one LED or several LEDs of the color red, and one LED or several LEDs of the color amber, and a control, wherein the control is adapted to control the LEDs (30) of the colors amber, red and warm white, when the blinder is switched off such that the color decay behavior of a halogen illuminant based blinder is mimicked, the control of the LEDs of the color warm white being such that the emitted power of the LEDs of the color warm white decreases substantially exponentially, the control of the LEDs of the color amber being such that the emitted power of the LEDs of the color amber initially increases with starting decrease of the LEDs of the color warm white, until a maximum decay power of the LEDs of the color amber is reached, and subsequently decreases substantially exponentially, and the control of the LEDs of the color red being such that the emitted power of the LEDs of the color red is substantially zero until the maximum decay power of the LEDs of the color amber is reached, subsequently increases until a maximum decay power of the LEDs of the color red is reached, and subsequently decreases substantially exponentially.

2. The LED module according to claim 1, wherein the number of LEDs of the color warm white, of the LEDs of the color red and of the LEDs of the color amber is more than 66% or the total number of LEDs of the LED module.

3. The LED module according to claim 1, comprising exclusively LEDs of the color warm white, LEDs of the color red and LEDs of the color amber.

4. The LED module according to claim 1, further comprising LEDs of the color green and/or LEDs of the color blue.

5. The LED module according to claim 1, wherein the LEDs of the color red have a dominant wave length in the range of 624 nm to 634 nm.

6. The LED module according to claim 1, wherein the LEDs of the color amber have a dominant wave length in the range of 585 nm to 600 nm.

7. The LED module according to claim 1, wherein the LEDs of the color warm white have a CRI (Color Rendering Index) of 80.

8. The LED module according to claim 1, wherein the LEDs of the color warm white have a color temperature of 3000K (CCT value).

9. The LED module according to claim 4, wherein the LEDs of the color green have a dominant wave length in the range of 520 nm to 540 nm.

10. The LED module according to claim 4, wherein the LEDs of the color blue have a dominant wave length in the range of 440 nm to 460 nm.

11. The LED module according to claim 10, wherein the control is PWM based.

12. A blinder comprising an LED module according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the invention is described by way of example taking into account the attached figures, in which:

(2) FIG. 1 shows a blinder with four groups in top view, wherein the front cover is removed at one member for illustration purposes;

(3) FIG. 2 shows a detail of FIG. 1;

(4) FIG. 3 shows an exemplary dimming curve of the LEDs of the color warm white;

(5) FIG. 4 shows an exemplary dimming curve of the LEDs of the color red;

(6) FIG. 5 shows an exemplary dimming curve of the LEDs of the color amber;

(7) FIG. 6 schematically shows an embodiment of a circuit board for a LED module according to the invention; and

(8) FIG. 7 schematically shows a further embodiment of a circuit board of a LED module according to the invention.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

(9) FIG. 1 shows a blinder 10 with four groups, i.e. a blinder having four lighting elements 20, which comprise a group of LEDs, respectively. Instead of the four lighting elements 20, which are shown in FIG. 1, it is in general also possible to group another number of lighting elements 20 to a blinder 10, for example two or six. The front cover of the lighting element 20 shown in the upper left corner is removed in the drawing in FIG. 1 for illustration purposes.

(10) FIG. 2 shows the lighting element of the top left corner of FIG. 1 in top view. The lighting element 20 comprises a central LED module 24, which has a circular basis face on which the LEDs are placed. Around this circular basis face a reflector member 22 is arranged in a concentric manner and opens conically in light emitting direction.

(11) The LED module 24 additionally comprises control and monitoring members (not shown in FIGS. 1 and 2) on a circuit board, apart of the circular area 24, where the LEDs are provided.

(12) FIGS. 6 and 7 show the exemplary arrangement of the LEDs 30 on the circuit board of the LED module 24 for two embodiments, respectively.

(13) FIG. 6 shows an embodiment where 72 LEDs 30 are provided in total, which are arranged in five concentric circles. In the embodiment according to FIG. 6 exclusively LEDs of the color warm white (denoted with W1-W57), of the color amber (denoted with A1-A12) and of the color red (denoted with R1-R3) are provided on the circuit board in a distributed manner. In particular, the major part of the LEDs 30 is provided in the color warm white (57 pieces) and corresponds to more than % of the total number of the LEDs provided.

(14) The LEDs of the color red (3 pieces) are provided rather close to the center of the arrangement, in particular on the second circle starting from the center and evenly distributed in circumferential direction, whereas the LEDs of the color amber (12 pieces) are distributed both in radial and in circumferential direction. With this distribution it is possible, when modelling the color decay behavior which is to correspond to that of a blinder with conventional halogen illumination technology, to not only mimic the color decay curve when dimming per se, but to also mimic the increasing concentration of reddish colors towards the center with increasing dimming.

(15) In the embodiment according to FIG. 7 there are additionally provided to the LEDs 30 of the colors red, amber and warm white LEDs or the colors green and blue. As in the embodiment according to FIG. 6, there are provided 72 LEDs 30 in total, wherein the LEDs 30 are provided in five concentric circles on the circuit board of the LED module 24. There are provided 12 LEDs of the colors amber, red, green and blue, respectively, and 24 LEDs of the color warm white. This means that the number of LEDs of the color warm white is double than the number of LEDs of the other colors amber, red, green and blue, respectively. In this embodiment, all colors are substantially evenly distributed both in radial direction and in circumferential direction.

(16) While the blinder effect, i.e. the extremely bright illumination of particular areas of a room, is produced in the color white, when using the blinder 10 having the LED arrangement according to FIG. 6, the arrangement according to FIG. 7 allows for producing the blinder effect in different colors, by specifically controlling separate, particular LEDs of particular colors. However, this results in a lower total power emitted as for the blinder 10 having the LED arrangement of FIG. 6, which has an impact on the achievable brightness.

(17) In both embodiments the LEDs of the colors red, amber and warm white are specifically controlled for generating a switch-off or decay behavior corresponding to that of a conventional blinder with halogen illuminants. The LEDs of the colors green and blue (in the case of the embodiment of FIG. 7) are not used for this purpose. FIGS. 3 to 5 show exemplary dimming curves (light power on the y-axis, time on the x-axis) for the colors warm white (FIG. 3), red (FIG. 4) and amber (FIG. 5). By increasing the red share of the emitted light with initially increasing colors amber and slightly delayed red and simultaneous decrease of the warm white share of the light, over and with advancing decay time, a color decay behavior is generated which substantially corresponds to that of a halogen light source and which mimics the reddish afterglow of an incandescent wire. For this purpose the LEDs are preferably controlled using pulse width modulation (PWM) corresponding to the frequent switching on and switching of, wherein the pulse width is correspondingly adjusted.

(18) The terms approximately, about, circa, substantially or in general, which are used here in combination with a detectable value, e.g. a parameter, an amount, a shape, a timely duration and the like, include deviations and variations of ?10% or less, preferably ?5% or less, further preferably ?1% or less and still further preferably ?0.1% or less of the respective value, as long as these deviations are technically reasonable. It is explicitly mentioned that the value to which about refers, is disclosed as exact value, as well. The indication of ranges by start and end values includes all these values and partial values which are included in these ranges, including start and end values.

(19) Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.