EP2487405B1 - Projector with gobo and method for operating the projector - Google Patents

Description

The present invention relates to spotlights and in particular to spotlights as they can be used for lighting for stages or installations, that is to say generally in show business.

Spotlights for creating light effects typically use mercury vapor lamps as white light sources and downstream gobo elements that are used as slide negatives or slides to create a colored light effect on a projection plane, such as a wall or canvas or other surface. In particular, stationary gobo elements or movable gobo elements, such as gobo wheels, can be used here in order to change the light effect. The gobo elements are designed to filter out a certain color spectrum from the white light emitted by the mercury vapor lamp, for example, in such a way that the output light is then, for example, a red star when the gobo element is otherwise non-transmitting for light, but has a star with a red color filter.

In the same way, a light effect with a blue star can be generated, for example, if the gobo element is designed in such a way that it is non-transmitting except for a blue filter.

The disadvantage of this procedure is that the efficiency of light generation is very low, especially when a colored light effect is desired. If, for example, a red light effect with a red gobo is generated from a mercury vapor lamp, only a portion of 10% of the light intensity will ultimately be available as headlight output as red light. This is problematic insofar as the existing gobo elements are very different due to the light heating, which makes special cooling of the gobo elements necessary, which has to be done, for example, by fans and thus creates additional space, additional costs, additional weight and additional noise.

The EP 1 411 290 A1 discloses a diode lighting system for stage, theater and architectural lighting. In particular, several diodes on a frame will do so attached so that each diode is directed to a prescribed distant focal point. An imaging gate is arranged between the LEDs and the focal point and has a gobo and a shutter.

The US patent publication 2001/0007527 A1 discloses a lighting device for projecting an image having a housing with a light emitting window. The housing includes a light source, an optical system, and an imaging surface. The light source is a single LED or LEDs of different colors are used. In addition, the image forming surface is designed as a gobo.

The US 2008/062681 A1 discloses a multi-parameter light that includes an LED tracking ring (light emitting diode) surrounding a main output lens. The LED tracking ring can be additively mixed in color and can in turn simulate the color of the projected main light that is projected from the main exit aperture or the exit lens of the multi-parameter light.

The EP 2 177 616 A2 discloses a light beam collecting element for LED arrays or other multi-source light fixtures. The light beam collecting system contains a light integrator that collects and integrates or homogenizes the light from a plurality of light sources, the light sources being configured in an array (130). The light integrator (306) is particularly useful with lights (360) used in lighting systems that use beam modulation elements (362, 364, 366) where it is desirable to have a narrow or narrow beam of light.

The object of the present invention is to create a more efficient concept for creating lighting effects.

This object is achieved by a headlight according to claim 1 or a method for operating a headlight according to claim 4.

The present invention is based on the knowledge that, in contrast to the prior art, in which only a subtractive color mixer in the form of a gobo element has been connected downstream of a white light source, now an additive color mixer as a light source with the subtractive color mixer in the form of, for example, a Gobo element is combined. This increases efficiency because the additive color mixer, which can be designed in the form of a 3-color LED lamp, for example, whereby the individual colors can be controlled independently by controlling the individual LED elements, are matched to the color transmission properties of the subtractive color mixer can. In addition, the subtractive color mixer can be such that it has at least two different transmission colors, so that when using one and the same subtractive color mixer, different color effects can be generated in the additive color mixer simply by controlling the individual lamps differently. A special implementation also consists in not placing the transmission colors of the subtractive color mixer on the basic colors of the additive color mixer, for example on red, green, blue of an RGB-LED color mixer, but on intermediate colors, such as yellow. Then the two component colors of yellow, i.e. H. red and green, can be created individually using the same pattern or in the same pattern of the gobo element.

In the implementation, the headlamp is designed to produce a light output power of at least 3000 lumens from the additive color mixer, e.g. B. an LED source to have a lighting property or a spotlight property. Due to thermal problems, it can also be advantageous to have a maximum light output power 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 exemplary embodiments of the present invention are explained in detail below with reference to the accompanying drawings. Show it:

Fig. 1

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

Fig. 2

an overview of the individual light effects that can be achieved with different gobo elements through alternative control of the additive color mixer; and

Fig. 3

an alternative representation of a gobo element with multi-color coating to represent different lighting effects, 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. The headlight housing 16 also houses an optical system 18 which can be adjusted by motors (not shown). In the same way, the alignment of the headlight 14 can also be achieved by motors that are shown in FIG Fig. 1 are not shown, also preferably adjustable, namely preferably in an axis of rotation and a pivot axis. The headlight further comprises an LED control 20 within the housing 16. In particular, it is preferred that the additive color mixer is designed as a three-color LED lamp, it being preferred that the 3-LED colors red, green and blue are. Alternative color LEDs, which also span the color space, can also be used, such as yellow, cyan, magenta, although RGB LED lamps are preferred due to their availability and greater output power. The individual LEDs can be controlled independently of one another by means of the LED control 20, specifically by means of control signals which can be input via a control input 22.

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

The present invention thus relates to a combination of a multicolor LED light source (mostly RGB) and multicolor gobos. In contrast to a so-called washlight, however, this is a spot that can depict the pattern, i.e. the gobo pattern, sharply. Such gobos can be fitted in a gobo wheel, the gobo wheel being rotatable in a spotlight in order to bring different gobo elements into the light path 24, which represents a certain color from the RGB color space, which is due to the setting of the Individual light sources have been generated via the control input 22. The light 24 is “treated” in the subtractive color mixer in such a way that the color of the output light beam 26 from the subtractive color mixer is, so to speak, a subset of the color of the beam 24 from the RGB color space. The optics 18 finally produce from the incident light beam 26, the output light beam 28, which has sufficient power to have lighting quality.

Gobos are typically applied to a heat-resistant material. One form of gobos are thin metal plates less than 0.5 mm thick, from which the shapes to be projected are separated, for example by etching or by laser or water cut. However, the accuracy that can be achieved in this way is low, since there are certain minimum web widths. In addition, a pattern to be projected must always contain support bars for the inner surface. The resulting projections are always monochrome and can only be colored in one color as a whole using the projector's color mixing unit.

Glass gobos represent an alternative option. Here, an opaque layer, for example made of chrome or aluminum, is vapor-deposited onto a heat-resistant support made of thin borosilicate glass (usually 1.1 mm to 1.2 mm). Then it is coated with a photosensitive masking lacquer, the pattern is exposed by laser exposure, developed, the pattern is etched out of the metal layer and the masking lacquer is removed. The whole thing can also be produced by removing the metal layer directly via laser exposure.

With this method, more precise structures can be produced. But the result is again monochrome. However, a dichroic color layer can now also be vapor-deposited instead of the metal layer. For example, if you coat with blue and etch out a triangle, you can see a white triangle on a blue background illuminated with white light. If illuminated with yellow light, it is a yellow triangle on a green background. With red light it is a red triangle on a purple background, etc.

In addition, there are multicolored glass gobos which are preferred for use in the present invention, that is to say in the headlight according to the invention. One variant consists in arranging several glass carriers one behind the other, each coated with a color layer and a partial color image depicted therein. Since the partial images are at a distance from one another along the optical axis due to the thickness of the glass, it is not possible to focus on all colors at the same time. 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 again limits the number of coating colors to two colors. Another more complex variant is to apply several layers one after the other to a common glass carrier and to 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 a high level of precision. However, the results that can be achieved are particularly advantageous.

The WO 98/00670 A1 discloses a method for producing a gobo and further discloses a gobo which has been produced by this method, wherein individual color components are arranged in parallel planes, at least two of these planes being separated from one another by means of a transparent substrate. The gobo comprises a plurality of plate-shaped and transparent substrates arranged one above the other, each substrate having a dichroic surface coating in order to be a color filter. Combinations of color filters are able to produce the colors of the multi-color structure.

It was found out that the color impression of such multicolored gobo projections is completely inverted if they are illuminated by means of multicolor LED light sources instead of discharge lamps with CMY color changers. The reason for this is that a headlight with a discharge lamp has its greatest possible intensity when it projects a white light beam, i.e. when 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 light intensity is inversely proportional to the color intensity. Since the color filter (or several in the case of CMY systems) only allows a narrow band of the radiated white light to pass through and reflects the rest back into the exterior of the luminaire, the less light is let through, the more of the respective filter is moved into the beam path. In the case of the multicolor LED light sources according to the invention, however, the current in the respective LED increases by adding a basic color, or, in the case of PWM control, the pulse-pause ratio. In contrast to the prior art, color intensity and light intensity increase at the same time. This change in color and brightness behavior is unusual and is therefore perceived by the viewer as particularly interesting and different. In addition, the light beam of this system usually only receives three or four different peak wavelengths, to which the colors of the gobo can preferably be perfectly adapted. The color impression is therefore much purer and more intense because, in contrast to the use of a mercury vapor lamp or a white light source, there are no unused intermediate wavelengths.

With the inventive combination of additive color mixer and subtractive color mixer, special effects can be achieved, as shown in Fig. 2 and Fig. 3 shown are. For example, if a color gobo with a red, a green and a blue point on an opaque background is illuminated by an RGB light source, you will see a certain pattern when all three light sources are on, as shown in Fig. 2 you can see. If only the red LED is on, only the red point lights up, the other two are practically invisible. If only the green LED is on, only the green point lights up and the other two are practically invisible. With blue this is accordingly,

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

However, the combination of color gobos and multi-color LED light source gives the lighting designers the opportunity to create the impression of different patterns in the viewer by selecting the gobo pattern and by controlling the light source accordingly, without actually having to change the gobo. On the one hand, this has the advantage that the pattern can be changed practically just by switching, i.e. at the speed of light (apart from the clock frequency of the data bus). In addition, the options available through color selection are multiplied by the number of gobos actually present in a gobo wheel. By combining an additive color mixture that takes place in the actual LED light source and a subtractive color mixture through the dichroic layers of the color gobos, particularly interesting effects are achieved, and a particularly efficient way of operating a spotlight is achieved, as well there is no longer any need for a problem with regard to the removal of the superfluous heat, because the heat is no longer generated.

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

In a preferred embodiment of the present invention, the subtractive color mixer used is a gobo which is coated with two different layers, the layers having two different transmission colors and others Colors outside of the transmission colors are not transparent. In one implementation, the transmission colors of the gobo are set to the basic colors that are present in the LED lamp, for example, as shown in the top left in Fig. 2 is shown. In an alternative implementation, however, it is preferred to place the transmission colors of at least one color layer on an intermediate color, so that even the color appearance of one and the same gobo and in particular of one and the same layer of the gobo by controlling differently between these two mixed colors, of which the transmission color of the gobo is composed, can be "tuned through". Alternatively, color filters of the individual gobo coatings can also be arranged one behind the other, so that a mixed color is created at the end, which exists when the RGB source simultaneously emits the two colors that make up the mixed color.

A light switchover or a change in the control of the RGB color source is preferably carried out, coordinated with the colors of the LED light source, so that one transmission color of one gobo coating is emitted at one point in time and the other transmission color at a later point in time the other gobo coating is emitted. If the transmission color of a gobo coating does not match the individual color of an individual LED element, it is preferred to activate the first color of the mixed color at a first point in time and not the other colors, and it is preferred to activate the other color at a second point in time to activate the mixed color and not the other colors, and it is further preferred to activate both colors at a third point in time in order to generate the actual mixed color. All of this happens without changing the gobo.

Various controls with different colors, such as those that can be performed sequentially, are in Fig. 2 and Fig. 3 shown, where Fig. 2 represents three different gobos with three different coatings each, depending on the implementation, as shown in the right Fig. 2 is shown to be irradiated with different light.

Fig. 3 also shows a further implementation of a gobo element with three coatings, which is also controlled by seven different states.

Claims (4)

1. A spotlight (14) comprising:

   an additive color mixer (10) as a light source, wherein the additive color mixer (10) comprises at least two lamps, a first lamp of the at least two lamps being configured to emit light in a first color, a second lamp of the at least two lamps being configured to emit light in a different second color, said at least two lamps being controllable independently of each other in terms of their intensities;

   a subtractive color mixer (12), the subtractive color mixer (12) comprising a gobo having several layers on one substrate, each layer being transparent to light having a different transmission color and being non-transparent to light that does not correspond to the transmission color, the subtractive color mixer (12) being configured to treat light (24) emitted by the additive color mixer (10); and

   a controller (20) for controlling a color output of the additive color mixer (10), said controller (20) being configured to control, in response to at least one control signal, the at least two lamps for different colors in the additive color mixer (10) independently of each other;

   a first layer of the several layers of the gobo being transparent to light having a first transmission color, said first transmission color equaling the first color, a second layer of the several layers of the gobo being transparent to light having a different second transmission color, said second transmission color equaling the second color, and the controller (20) being configured to alternately control the at least two lamps such that, at a first point in time, the first light having the first transmission color is emitted, and no or less light having the second transmission color is emitted, and that at a second, later point in time, the second light having the second transmission color is emitted, and no or less light having the first transmission color is emitted; or

   a first layer of the several layers of the gobo being transparent to light having a first transmission color, and a second layer of the several layers of the gobo being transparent to light having a different second transmission color, at least one of the first and second transmission colors of the gobo being such that it does not match the colors emitted by the individual lamps, but is a mixture of the first color and of the second color or of several colors of the at least two lamps, and the controller being configured to alternately control the at least two lamps

   such that, at a first point in time, a lamp for emitting light having the first color of the mixture is active, and the other at least one lamps are not active,

   such that, at a second point in time, a different lamp for emitting a different light of the mixture is active, and the one lamp is not active, and

   such that, at a third point in time, the at least two lamps for emitting the two colors of the mixture are active.
2. The spotlight (14) as claimed in claim 1, wherein the at least two lamps are LED lamps, and the additive color mixer (10) comprises at least a third LED lamp, each LED lamp being configured to emit light having a different color, said three LED lamps being controllable independently of one another in terms of their intensities, and the three LED lamps being configured such that together they define a color space.
3. The spotlight (14) as claimed in claim 2, wherein the LED lamps comprise an LED lamp emitting red, an LED lamp emitting green, and an LED lamp emitting blue.
4. A method of operating a spotlight (14) comprising an additive color mixer (10) as a light source, wherein the additive color mixer (10) comprises at least two lamps, a first lamp of the at least two lamps being configured to emit light in a first color, a second lamp of the at least two lamps being configured to emit light in a different second color, said at least two lamps being controllable independently of each other in terms of their intensities; a subtractive color mixer (12), the subtractive color mixer (12) comprising a gobo having several layers on one substrate, each layer being transparent to light having a different transmission color and being non-transparent to light that does not correspond to the transmission color, the subtractive color mixer (12) being configured to treat light (24) emitted by the additive color mixer (10); and a controller (20) for controlling a color output of the additive color mixer (10), said controller (20) being configured to control, in response to at least one control signal, the at least two lamps for different colors in the additive color mixer (10) independently of each other, comprising the step of:

   a first layer of the several layers of the gobo being transparent to light having a first transmission color, said first transmission color equaling the first color, a second layer of the several layers of the gobo being transparent to light having a different second transmission color, said second transmission color equaling the second color, controlling the at least two lamps of the additive color mixer (10) such that, at a first point in time, the first light having the first transmission color is emitted, and no or less light having the second transmission color is emitted, and that at a second point in time, the second light having the second transmission color is emitted, and no or less light having the first transmission color is emitted; or

   a first layer of the several layers of the gobo being transparent to light having a first transmission color, and a second layer of the several layers of the gobo being transparent to light having a different second transmission color, at least one of the first and second transmission colors of the gobo being such that it does not match the colors emitted by the individual lamps, but is a mixture of the first color, the second color or of several colors of the at least two lamps, controlling the at least two lamps of the additive color mixer (10)

   such that, at a first point in time, a lamp for emitting light having the first color of the mixture is active, and the other at least one lamps are not active,

   such that, at a second point in time, a different lamp for emitting a different light of the mixture is active, and the one lamp is not active, and

   such that, at a third point in time, the at least two lamps for emitting the two colors of the mixture are active.

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