EP2487405A1 - Headlamp and method for operating same - Google Patents

Abstract

The headlamp (14) has Scheinwerfer (14) mit folgenden Merkmalen:an additive color mixer (10) that is used as a light source, and a subtractive color mixer (12) that are accommodated within housing (16). The additive color mixer is comprised of two lamps or three LEDs which are designed to emit light rays in different colors. The light intensities of the two lamps are independently controlled. The LEDs are configured such that the LEDs are combined to define a color space. The LEDs are red, green and blue LEDs. An independent claim is included for method for operating headlamp.

Description

The present invention relates to headlamps, and more particularly to headlamps of the type that can be used for stage or installation lighting, generally in show business.

Headlamps for producing light effects typically use mercury vapor lamps as white light sources and subordinate gobo elements used as dianegatives or slides to produce a color light effect on a projection plane, such as a wall or canvas or other surface. In particular, resting gobo elements or movable gobo elements, such as gobo wheels, can be used here to change the light effect. The gobo elements are designed to filter out a specific color spectrum from the white light emitted by the mercury vapor lamp, for example, such that the output light is then, for example, a red star, if the gobo element is otherwise non-transmissive to light, however, has a star with a red color filter.

Similarly, a blue star lighting effect can be generated, for example, if the gobo element is designed to be non-transmissive except for a blue filter.

A disadvantage of this approach is that the efficiency of light generation, especially when a colored light effect is desired, is very low. If, for example, a red light effect is produced from a mercury vapor lamp with a red gobo, only a proportion of 10% of the light intensity at the end will be available as a headlight output as red light. This is problematic in that the existing gobo elements are very much due to the Lichtauflieizens what a special cooling of the gobo elements required, for example, must be done by fans and thus generates additional space, additional costs, additional weight and additional noise.

The object of the present invention is to provide a more efficient concept for generating light effects.

This object is achieved by a headlight according to claim 1 or a method for operating a headlamp according to claim 11.

The present invention is based on the finding that, in contrast to the prior art, in which only a subtractive color mixer in the form of a gobo element of a white light source has been connected, now an additive color mixer as a light source with the subtractive color mixer in the form of a Gobo element is combined. Thus, the efficiency is increased because the additive color mixer, which may be formed for example in the form of a 3-color LED lamp, wherein the individual colors are controlled independently by driving the individual LED elements, are matched to the color transmission properties of the subtractive color mixer can. In addition, the subtractive color mixer may be such that it has at least two different transmission colors, so that when using the same subtractive color mixer alone by different control of the individual lamps in the additive color mixer different color effects can be generated. A particular implementation is also not to place the transmission colors of the subtractive color mixer on the primary colors of the additive color mixer, for example on red, green, blue of an RGB LED color mixer, but on intermediate colors, such as in yellow. Then, by appropriately driving the additive color mixer, the two components colors of yellow, d. H. red and green individually using the same pattern or pattern of the gobo element.

In the implementation, the headlamp is designed to provide a light output of at least 3000 lumens from the additive color mixer, e.g. As an LED source, to meet a lighting property or a Spotlighteigenschaft. Due to thermal problems, it may also be advantageous to have a maximum light output of less than 8000 lumens.

Fig. 1

ein Blockschaltbild eines Scheinwerfers gemäß einem Ausführungsbeispiel der vorliegenden Erfindung;

Fig. 2

eine Übersicht über einzelne Lichteffekte, die mit unterschiedlichen Gobo-Elementen durch alternatives Ansteuern des additiven Farbmischers erreichbar sind; und

Fig. 3

eine alternative Darstellung eines Gobo-Elements mit Mehrfarb-Beschichtung, um verschiedene Lichteffekte darzustellen, wobei Sternmuster dargestellt sind.

Preferred embodiments of the present invention will be explained below in detail with reference to the accompanying drawings. Show it:

Fig. 1

a block diagram of a headlamp according to an embodiment of the present invention;

Fig. 2

an overview of individual lighting effects that can be achieved with different gobo elements by alternative driving the additive color mixer; and

Fig. 3

an alternative representation of a gobo element with multi-color coating to represent different lighting effects, with star patterns are shown.

Fig. 1 shows an additive color mixer 10 and a downstream subtractive color mixer 12 within a headlight 14 with a headlight housing 16. In the headlight housing 16, a lens 18 is further housed, which is adjustable by motors (not shown). Similarly, the orientation of the headlamp 14 is also by motors that are in Fig. 1 not shown, also preferably adjustable, preferably in a rotational axis and a pivot axis. The headlamp further includes an LED controller 20 within the housing 16. More specifically, it is preferred that the additive color mixer is formed as a tri-color LED lamp, with it being preferred that the 3-LED colors be red, green, and blue are. Alternative color LEDs, which also span the color space, are also usable, such as yellow, cyan, magenta, however, due to the availability and the greater output power, RGB LED lamps are preferred. By the LED controller 20, the individual LEDs are independently controllable, by control signals which can be input via a control input 22.

The subtractive color mixer 12 preferably comprises a coated glass gobo, and more particularly a glass gobo with two or more layers.

The present invention thus relates to a combination of a multi-color LED light source (usually RGB) and multi-color gobos. In contrast to a so-called Washlight, however, this is now about a spot, the pattern, so the gobo pattern can depict sharply. Such gobos can be fitted in a gobo wheel, the gobo wheel being rotatable in a headlight to bring different gobo elements into the light path 24, which represents a particular color from the RGB color space due to the setting of the Single light sources has been generated via the control input 22. The light 24 is "treated" in the subtractive color mixer such that the color of the output light beam 26 from the subtractive color mixer is effectively a subset of the color of the beam 24 from the RGB color space. The optics 18 finally generates from the incident light beam 26, the output light beam 28 having sufficient power to have illumination quality.

Gobos are typically applied to a refractory material. One form of gobos are thin metal plates of less than 0.5 mm thickness, from which the forms to be projected are separated out, for example by etching or by laser or watercut. The achievable accuracy is low because there are certain minimum ridge widths. In addition, a pattern to be projected must always contain support webs for the inner surface. The resulting projections are always monochrome and can only be colored as a whole with the color mixing unit of the projector in one color.

An alternative possibility is glass gobos. In this case, a light-impermeable layer, for example of chromium or aluminum, is vapor-deposited on a heat-resistant support made of thin borosilicate glass (usually 1.1 mm to 1.2 mm). Thereafter, it is coated with a photosensitive resist, exposed by laser exposure pattern, developed, etched the pattern from the metal layer and the Abdecklack removed. The whole thing can also be produced by removing the metal layer directly by laser exposure.

With this method, more accurate structures can be generated. The result is again monochrome. However, instead of the metal layer, it is now possible to evaporate a dichroic ink layer. For example, if you coat with blue and etched out a triangle, you can see a white triangle on a blue background illuminated with white light. When illuminated with yellow light, it is a yellow triangle on a green background. In red light, it is a red triangle on a violet ground, etc.

In addition, there are multicolored glass gobos, which are preferred for use in the present invention, so in the headlamp invention. One variant consists of arranging a plurality of glass carriers in succession, which are each coated with a color layer and a color partial image imaged therein. Since the subpictures have a distance along the optical axis, because of the glass material thickness, a simultaneous focusing on all colors is not possible. So there is a certain blurring effect. This problem can be avoided by arranging only two carriers so that the coated sides touch each other. A partial image is applied mirror-inverted. This restricts the number of coating colors back to two colors. Another more complex variant is to successively apply several layers to a common glass substrate and etch out the partial images. Since each new layer can only be applied when the previous pattern has already been etched out of its layer, this is a time-consuming process that also requires high precision. However, the achievable results are particularly advantageous.

The WO 98/00670 A1 discloses a method of making a gobo and further discloses a gobo made by this method wherein single color components are arranged in parallel planes with at least two of these planes separated by a transparent substrate. The gobo comprises a plurality of superimposed plate-shaped and transparent substrates, each substrate having a dichroic surface coating to be a color filter. Combinations of color filters are capable of producing the colors of the multi-color structure.

Thus, it has been found that the color impression of such multicolor gobo projections is completely inverted when illuminated by multicolor LED light sources rather than by CMY color changer discharge lamps. The reason for this is that a headlamp with discharge lamp then has its greatest possible intensity when it projects a white beam of light, so if no color filters are arranged in the beam path. If this light beam is colored by means of a color mixing stage, for example with CMY color mixing with dichroic color filters, the luminous intensity behaves inversely proportional to the color intensity. Since the color filter (or more in CMY systems) transmits only a narrow band of irradiated white light and reflects the rest back into the exterior of the luminaire, the less light is transmitted, the more is driven by the respective filter in the beam path. However, in the multicolor LED light sources of the present invention, by adding a base color, the current in the respective LED increases or, in the case of PWM driving, the plus-pause ratio. Color intensity and light intensity increase in contrast to the prior art thus simultaneously. This change in color and brightness behavior is unfamiliar and is therefore perceived by the viewer as particularly interesting and different. In addition, the light beam of this system usually receives only three or four different peak wavelengths, to which the colors of the gobo can preferably be perfectly adapted. The color impression is therefore much cleaner and more intense color, since there are no unused intermediate wavelengths in contrast to the use of a mercury vapor lamp or a white light source.

With the combination of additive color mixer and subtractive color mixer according to the invention, special effects can be achieved, as they are known in Fig. 2 and Fig. 3 shown are. For example, if a color gobo with a red, a green, and a blue dot on an opaque background is illuminated by an RGB light source, you will see a particular pattern when all three light sources are on, as in Fig. 2 you can see. If only the red LED is on, only the red dot is lit, the other two are practically invisible. If only the green LED is on, only the green dot is lit, and the other two are practically invisible. If blue this is appropriate,

If one were to use this gobo in a device with a discharge lamp, the two other points would still be a bit visible, since the dichroic filters of the color mixing stage are not narrow-band enough to completely blank out all intermediate wavelengths of the discharge lamp. In addition, the usable brightness would be lowest if the largest color purity of a single color would be irradiated, since then the filter blocks most of the light.

However, the combination of color gobos and multi-color LED light source now gives lighting designers the ability to create the impression of different patterns by choosing the gobo pattern and controlling the light source without actually having to change the gobo. This has the advantage that the change of the pattern is practically possible only by switching, ie in the speed of light (apart from the clock frequency of the data bus). In addition, the possibilities offered by color selection are multiplied by the number of actual gobos in a gobo wheel. By combining an additive color mixture, which takes place in the actual LED light source and a subtractive color mixture through the dichroic layers of the color gobos thus particularly interesting effects are achieved, and a particularly efficient way of operating a headlamp is achieved, as well No problem with regard to the removal of superfluous heat is more necessary because the heat is no longer generated.

In contrast to white light LED spots or discharge lamp spots, where there is no possibility to scatter the light color of the light source, but only the possibility of subtractive color mixing outside the light source, this is just achieved according to the invention, namely by the additive color mixer already during light generation a color from the RGB color space 24 (FIG. Fig. 1 ) can be generated.

In a preferred embodiment of the present invention, the subtractive color mixer used is a gobo coated with two different layers, the layers having two different transmission colors and others Colors outside the transmission colors are not transparent. In one implementation, the transmission colors of the gobo are adjusted to the basic colors that are present in the LED lamp, as shown, for example, in the upper left corner of FIG Fig. 2 is shown. In an alternative implementation, however, it is preferred to apply the transmission colors of at least one color layer to an intermediate color such that even the color appearance of one and the same gobo and, in particular, of one and the same layer of the gobo, by differentially driving between these two mixed colors, of which the transmission color of the gobo can be "tuned". Alternatively, color filters of the individual Gobo coatings can be arranged one behind the other, so that at the end of a mixed color arises, which exists when the RGB source emits the two colors of which the mixed color is composed simultaneously.

Preferably, a light change or a change in the control of the RGB color source is made, specifically matched to the colors of the LED light source, so that at one time the one transmission color of a Gobo coating is emitted and at a later time the other transmission color the other Gobo coating is emitted. If the transmission color of a gobo-coating does not match the single color of a single LED element, it is preferred to activate the first color of the mixed color at a first time and not the other colors, and it is preferred to use the other color at a second time to activate the mixed color and not the other colors respectively, and it is further preferred to activate both colors at a third time to produce the actual mixed color. All this happens without gobo change.

Various controls with different colors, as they can be made sequentially, are in Fig. 2 and Fig. 3 shown, where Fig. 2 Three different gobos with different three coatings each, depending on the implementation, as it is right in Fig. 2 is shown to be charged with different light.

Fig. 3 Figure 12 also shows another implementation of a gobo element with three coatings, which is also driven by seven different states.

Claims (11)

Headlamp (14) with the following features: an additive color mixer (10) as a light source; and a subtractive color mixer (12). A headlamp according to claim 1, wherein the additive color mixer (10) comprises at least two lamps adapted to emit light of different colors, the at least two lamps being independently controllable in intensity. A headlamp according to claim 1 or 2, wherein the additive color mixer (10) comprises at least three LEDs, each LED being adapted to emit a light of a different color, the three LEDs being independently controllable in intensity. A headlight according to any one of the preceding claims, wherein the additive color mixer (10) comprises at least three LEDs adapted to define a color space together. A headlight according to claim 4, wherein the LEDs comprise a red emitting LED, a green emitting LED and a blue emitting LED. A headlamp (14) according to any one of the preceding claims, further comprising: a controller (20) for controlling a color output of the additive color mixer (10), the controller being configured to independently drive individual light sources for different colors in the additive color mixer (10) in response to at least one control signal. A headlight according to any one of the preceding claims, wherein the subtractive color mixer (12) is a gobo. A headlamp according to claim 7, wherein the gobo (12) is a multi-layer gobo on a substrate, each layer being one light with another Transmission color is transparent and is not transparent to light that does not correspond to the transmission color. Headlamp according to one of the preceding claims, further comprising: a controller (20) for controlling a color output of the additive color mixer (10), the controller being arranged to independently drive individual light sources for different colors in the additive color mixer (10) in response to at least one control signal; wherein the subtractive color mixer (12) comprises a multi-layer gobo on a substrate, each layer being transparent to a light having a different transmission color and not being transparent to light that does not correspond to the transmission color. wherein the controller (20) is adapted to control the light source alternately so that at a first time the first transmission color is emitted and at a second later time the second transmission color is emitted. Headlamp according to one of claims 1 to 5,
further comprising: a controller (20) for controlling a color output of the additive color mixer (10), the controller being arranged to independently drive individual light sources for different colors in the additive color mixer (10) in response to at least one control signal; wherein the subtractive color mixer (12) comprises a multi-layer gobo on a substrate, each layer being transparent to a light having a different transmission color and not being transparent to light that does not correspond to the transmission color. wherein the transmission colors are such that they do not coincide with the colors emitted by the individual light sources but are a mixture of two or more colors of the light source, wherein the controller is configured to alternately drive the light source so that, at a first time, a light source for emitting light with the first color of the mixture is active and the other light sources are not, at a second time, another light source for emitting another Light of the mixture is active and the one light source is not and that at a third time both light sources for emitting the two colors of the mixture are active. A method of operating a headlamp according to any one of claims 1 to 10, wherein the subtractive color mixer (12) comprises a multi-layer gobo on a substrate, each layer being transparent to a light having a different transmission color and to light not being the transmission color corresponds, is not transparent, with the following steps: Driving the additive color mixer (10) so that at a first time, a light having the first transmission color or a part of the light having the first transmission color and no or less light of the second transmission color is emitted, and at a second time, a light with the second transmission color or a part of the light with the second transmission color and no or less light of the first transmission color is emitted.

Images