Patent Description:
The disclosure generally relates to an automated luminaire, specifically to a heat protection and homogenization system in an automated luminaire.

Luminaires with automated and remotely controllable functionality are well known in the entertainment and architectural lighting markets. Such products are commonly used in theatres, television studios, concerts, theme parks, night clubs and other venues. Such a luminaire may provide control over the direction the luminaire is pointing and thus the position of the light beam on the stage or in the studio. This directional control may be provided via control of the luminaire's orientation in two orthogonal axes of rotation usually referred to as pan and tilt. Some products provide control over other parameters such as the intensity, color, focus, beam size, beam shape and beam pattern. The beam pattern may be provided by a stencil or slide called a gobo which may be a steel, aluminum or etched glass pattern.

Reference is made to <CIT> which has been cited as representative of the state of the art. Patent specification <CIT> describes luminaires, luminaire systems and methods for controlling the light output from a lamp and reflector when used in a light beam producing luminaire.

It will be appreciated that the scope of the invention is in accordance with the claims. The invention is directed to an automated luminaire as defined in claim1.

In one embodiment of the disclosure, an automated luminaire includes a light source, an ellipsoidal reflector, an optical device, and a controller. The ellipsoidal reflector is optically coupled to the light source and produces an emitted light beam. The ellipsoidal reflector has an optical axis and moves relative to the light source along its optical axis. The optical device receives the emitted light beam and produces either a modified light beam or an unmodified light beam. The controller is configured to determine whether the optical device is producing the modified or unmodified light beam and, in response to determining that the optical device is producing the modified light beam, to move the ellipsoidal reflector to a selected position relative to the light source.

In another not claimed embodiment, a method for use in an automated luminaire includes determining whether an optical device of the automated luminaire is producing a modified or unmodified light beam from an emitted light beam received by the optical device. The method further includes reducing an effect on the optical device of a hotspot in the emitted light beam by moving an ellipsoidal reflector to a selected position in response to determining that the optical device is producing the modified light beam.

According to the invention, an automated luminaire includes a light source, an optical device, and a controller. The light source produces an emitted light beam and includes an ellipsoidal reflector and a short arc discharge lamp. The lamp is fixedly mounted with its arc positioned near a first focus of the ellipsoidal reflector. The combination of the reflector and the light source is referred to as a combined light source. The light source has an optical axis and is configured to move along the optical axis. The optical device receives the emitted light beam and produces either a modified light beam or an unmodified light beam. The controller determines whether the optical device is producing the modified or unmodified light beam and, if the optical device is producing the modified light beam, moves the light source along the optical axis to a selected position relative to the optical device. The position is selected to locate a second focus of the ellipsoidal reflector in front of or behind the optical device.

For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in conjunction with the accompanying drawings in which like reference numerals indicate like features.

Preferred embodiments are illustrated in the figures, like numerals being used to refer to like and corresponding parts of the various drawings.

Disclosed herein is an automated luminaire (or fixture), specifically the design and operation of a heat protection and homogenization system for use within an automated luminaire utilizing a light source with an intense hotspot such that the luminaire is capable of producing a narrow light beam in a first mode, and, in a second mode, capable of producing a wide, even, wash beam or projecting gobos without damaging the gobos or compromising the narrow beam performance of the first mode.

The optical systems of automated luminaires may be designed such that a very narrow output beam is produced, so that the units may be used with long throws or for almost parallel light laser like effects. Such optics may be called 'Beam' optics. In fixtures with a large light source, such a narrow beam may be formed using a large output lens with a large separation between the lens and the luminaire's gobos. In other such fixtures, an output lens with a short focal length may be positioned closer to the gobos.

Having a large separation with a large lens can cause the luminaire to be large and unwieldy and may make automation of the fixture's pan and tilt movement more difficult. In some systems, a preferred solution is a closer and smaller lens with a short focal length. In other systems a Fresnel lens may be used as a front lens, providing the same focal length with a lighter, molded glass lens having multiple circumferential facets. Fresnel lenses can provide a good match to the focal length of an equivalent plano-convex lens, however the image projected by a Fresnel lens may be soft edged and fuzzy and not provide as sharp an image as may be desired when projecting gobos or patterns.

<FIG> illustrates a multiparameter automated luminaire system <NUM>. The luminaire system <NUM> includes a plurality of multiparameter automated luminaires <NUM> which each contains an on-board light source (not shown), light modulation devices, electric motors coupled to mechanical drive systems, and control electronics (not shown). In addition to being connected to mains power either directly or through a power distribution system (not shown), the luminaires <NUM> are connected in series or in parallel via a data link <NUM> to one or more control desks <NUM>. The luminaire system <NUM> may be controlled by an operator using the control desk <NUM>. Control of an individual automated luminaire <NUM> is typically effectuated by electromechanical devices within the luminaire <NUM> and electronic circuitry <NUM> including firmware and software within the control desk <NUM> and/or the luminaire <NUM>. The luminaire <NUM> and the electronic circuitry <NUM> may also be referred to collectively as a fixture. In many of the figures herein, important parts like electromechanical components such as motors and electronic circuitry including software and firmware and some hardware are not shown in order to simplify the drawings. Persons of skill in the art will recognize where these parts have been omitted.

<FIG> illustrates an automated luminaire <NUM>. A lamp <NUM> includes a light source <NUM> which emits light. The light is reflected and controlled by a reflector <NUM> through one or more of a static hot mirror <NUM>, aperture or imaging gate <NUM>, and optical devices <NUM> and <NUM>. The optical devices <NUM> and <NUM> may include one or more of dichroic color filters, effects glass and other optical devices. The optical devices <NUM> and <NUM> may be imaging components and may include gobos, rotating gobos, irises, and/or framing shutters. A final output beam may be transmitted through focusing lens <NUM> and output lens <NUM>. Output lens <NUM> may be a short focal length glass lens or equivalent Fresnel lens as described above. The optical devices <NUM> and <NUM>, focusing lens <NUM>, and/or output lens <NUM> may be moved along the optical axis of the automated luminaire <NUM> to provide focus and/or beam angle adjustment for the imaging components. Static hot mirror <NUM> may protect the optical devices <NUM> and <NUM> from high infra-red energy in the light beam, and typically comprises a glass plate with a thin film dichroic coating designed to reflect long wavelength infra-red light radiation, thus allowing only the shorter wavelength, visible light to remain in the light beam. However, in such designs, the static hot mirror <NUM> is always in position, modifying the light beam.

Some lamps <NUM> have extremely small light sources <NUM>. Such light sources may have a very short arc gap, on the order of <NUM> millimeter (mm), between two electrodes as the light-producing means. Such lamps are well-suited for producing a very narrow beam, as their source etendue is low. Furthermore, the size of the lenses and optical devices to collimate the light from such a small source can be substantially reduced. However, the short arc and small light source coupled with a short focal length, and thus large light beam angles, of the reflector can result in a light beam with large amounts of energy concentrated in the central region, known as a hotspot. This intense central energy region is not ideal for producing a large even wash of light, and can damage or destroy elements of optical devices <NUM> and <NUM>. In particular, glass gobos and projection patterns may be damaged by such an intense central hotspot. The light energy may damage the surface coatings and materials of the gobos.

Optical systems according to the present disclosure are capable of producing a narrow light beam in a first mode, and also, in a second mode, of producing a wide wash beam or of projecting gobos without damaging the gobos.

<FIG> presents a schematic side view of an optical system <NUM> according to the disclosure. The optical system <NUM> includes a light source <NUM> mounted in a fixed position within reflector <NUM> (the combination of light source <NUM> and reflector <NUM> may be referred to as a combined light source). Light source <NUM> may be a short arc discharge lamp with arc length of approximately <NUM>, and reflector <NUM> may be positioned near a first focus of the ellipsoidal glass reflector <NUM>. The combination of a short arc light source and an ellipsoidal reflector produces a light beam towards a second focus of the ellipsoidal reflector. Such a beam typically has a very high energy beam center, or hotspot. The beam also produces a poor wide beam pattern when trying to use the luminaire as a wash light.

In the optical system <NUM>, the light beam emitted by the light source <NUM> and reflector <NUM> passes through a heat protection and homogenization system (compensation module) <NUM> and the resulting compensated light beam passes through optical devices color system <NUM>, static gobo system <NUM>, and rotating gobo system <NUM>. In other embodiments, one or more of systems <NUM>, <NUM>, and <NUM> may be omitted. The light beam then continues through lenses <NUM>, <NUM>, and <NUM>, which may each individually or collectively be moveable along optical axis <NUM> so as to alter one or more of the focus, beam angle, and/or zoom of the light beam produced by the optical system <NUM>.

Optical elements such as static gobo system <NUM> and rotating gobo system <NUM> may contain gobos or patterns that can be damaged by an intense hotspot. Such gobos may have a glass substrate with layers of aluminum, thin film coatings or other means for creating an image layer on the glass. The energy gradient from a light beam with an intense hotspot may damage these coatings, or crack or melt the glass. Similarly, devices such as irises or framing shutters may be damaged by the hotspot. The compensation module <NUM> provides protection for optical elements by introducing either a diffuser or hot mirror into the light beam, when such protection is required. The compensation module <NUM> also provides for the removal of both diffuser and hot mirror from the beam when no optical element protection is required and an unmodified light beam is desired.

The compensation module <NUM> protects optical elements that are sensitive to a beam hotspot by automatically introducing a diffuser into the light path whenever a gobo or other heat sensitive element is inserted into the light beam. This diffuser may also be automatically removed from the light beam when all hotspot sensitive or heat sensitive devices are removed from the light beam, and may be replaced with a hot mirror. In some circumstances, an operator may manually control the compensation module <NUM> so that the diffuser is across the light beam when it is desired to produce a wide, smooth light beam for use as a wash light. In such circumstances, lenses <NUM>, <NUM>, and <NUM> may be adjusted to produce a wide beam angle or zoom, and the resultant beam will be smooth and flat with no intense bright central hotspot. In other circumstances, the operator may manually control the compensation module <NUM> so that the hot mirror is across the light beam when it is desired to produce a very tight, narrow beam of light. In such circumstances the central hotspot is useful to the optics and it is desirable to remove all homogenization or diffusion such that the light beam is as narrow and sharp as possible. In still other circumstances, the operator may manually control the compensation module <NUM> so that neither the diffuser nor the hot mirror is across the light beam.

<FIG> presents a schematic isometric view of the optical system <NUM> of <FIG> with the compensation module <NUM> in a first configuration. The compensation module <NUM> includes an arm <NUM> to which are mounted hot mirror <NUM> and diffuser <NUM>. The hot mirror <NUM> and the diffuser <NUM> may be referred to as compensation elements. Hot mirror <NUM>, which is positioned in the light beam in <FIG>, is a filter that may be fabricated as one or more thin film coatings on glass, which reflects infra-red and other long wavelength energy, while allowing visible light to pass through. Diffuser <NUM>, which is positioned out of the light beam in <FIG>, is a homogenizing filter. The diffuser <NUM> may be manufactured as a frosted glass, lenticular glass, bead lens or filter, particulate frost filter, microlens array, or other kind of homogenizing filter. The diffuser <NUM> acts to spread out or dissipate any central hotspot in the light beam, providing a flatter, more diffuse beam that will not damage optical devices <NUM>, or gobos mounted on the static gobo system <NUM> and the rotating gobo system <NUM>, and will produce a smoother wash light beam.

<FIG> presents a schematic isometric view of the optical system <NUM> of <FIG> with the compensation module <NUM> in a second configuration. In this figure the arm <NUM> has been rotated so that the diffuser <NUM> is in the optical path and the hot mirror <NUM>, is removed from the optical path. The compensation module <NUM> may be rapidly rotated from a first position where the hot mirror <NUM> is in the optical path to a second position where the diffuser <NUM> is in the optical path. The means for this movement may be as shown in the figures using the pivoted arm <NUM> driven through gears and a stepper motor (not shown). In other embodiments, movement of the compensation elements may be through other mechanical means such as linear actuators, lead screw, rack and pinion drive, direct drive motors, servo motors, solenoids or other mechanical actuators. In some embodiments, the hot mirror <NUM> and the diffuser <NUM> may be moved by separate arms or other actuators, permitting either or both to be inserted or removed from the light beam, as desired.

<FIG> shows cross-sectional views of the optical system <NUM> of <FIG> with the compensation module <NUM> in the first and second configurations, respectively. In <FIG>, the hot mirror <NUM> is in the optical path, as shown by the optical axis marker <NUM>. In <FIG>, the arm <NUM> has been rotated so that diffuser <NUM> is in the optical path, again as shown by the optical axis marker <NUM>.

<FIG> presents an isometric view of the compensation module <NUM> of the optical system <NUM> of <FIG>. <FIG> presents a side view of the compensation module <NUM> of the optical system <NUM> of <FIG>. In this embodiment, the hot mirror <NUM> is mounted at an angle to the optical axis <NUM>, which lies parallel to an axis of rotation <NUM> of the arm <NUM>. By angling hot mirror <NUM>, the infra-red and other long wavelength energy reflected by hot mirror <NUM> is not sent back directly into the lamp, potentially overheating it. Instead, that energy is deflected to one side, away from the light source <NUM>.

The diffuser <NUM> may be constructed of a single substrate as shown in <FIG> or may comprise two or more layers. In some embodiments, the diffuser <NUM> may be a single substrate with a hot mirror coating on one of its surfaces so as to also act as a hot mirror as well as a diffuser. In other embodiments, the diffuser <NUM> may comprise two or more substrates, of which at least a first substrate is a diffuser or homogenizer and at least a second substrate is a hot mirror.

In a further embodiment, the compensation module <NUM> may continually oscillate between two positions on either or both of the hot mirror <NUM> or the diffuser <NUM> while they are positioned in the beam. In some circumstances the compensation elements themselves could be sensitive to the damaging effects of the hotspot it is being used to mitigate. In such circumstances, the compensation elements may be continually moved back and forth across the light beam, exposing different portions of the active compensation element to the hotspot and spreading the heat energy over a larger area of the compensation element. <FIG> illustrate this technique.

<FIG> presents a view of the compensation module <NUM> in a first position of the first configuration. A first portion of the hot mirror <NUM> is on the optical axis <NUM>, as shown by the marker <NUM>. <FIG> presents a view of the compensation module <NUM> in a second position of the first configuration. In <FIG>, compensation module <NUM> has been rotated and a second portion of the hot mirror <NUM> is on the optical axis <NUM>, as shown by the optical axis marker <NUM>. In a preferred embodiment, this oscillation is modulated at rates of approximately <NUM> hertz (Hz) in a sinusoidal pattern, when position is graphed against time. In other embodiments, other movement rates, oscillation frequencies, or position wave patterns may be employed.

The diffuser <NUM> may be similarly protected by oscillating the arm <NUM>. In other embodiments, color wheels could be modulated in a similar manner. However, in such an embodiment, the color filters on the color wheel would have to be large enough to allow for a sufficient range of oscillation motion. The range of motion necessary, in the case of a color wheel may be different for different colors.

<FIG> presents a flow chart <NUM> of a process of controlling a heat protection and homogenization system according to the disclosure. The flow chart <NUM> describes logic for protecting heat sensitive optical elements of an automated luminaire. The process described by the flow chart <NUM> may be performed by the control system described below with reference to <FIG>.

When the automated luminaire is on, the system monitors whether the luminaire is producing a modified light beam, for example, by placing a heat sensitive optical element in the light beam (step <NUM>). If the system determines that the luminaire is not producing a modified light beam (or if the beam is modified by an optical element that is not heat sensitive), then the hot mirror <NUM> is selected to engage the light beam. (step <NUM>). The system then monitors the operation of the luminaire to determine whether the status of the luminaire may cause risk of damage to the hot mirror <NUM> (step <NUM>). If so, the hot mirror <NUM> is scanned or oscillated as described with reference to <FIG> (step <NUM>) and the system returns to step <NUM> to look for a change in light beam modification status. In determining a risk of damage to the hot mirror <NUM>, the system may consider, how long the hot mirror <NUM> has been engaged, how long it is expected to be engaged given preprogramed lighting instructions, fixture temperature, ambient temperature, and/or other factors. In other embodiments, the logic can dictate that whenever the luminaire optical elements are repositioned to produce an unmodified light beam, the hot mirror <NUM> is selected to engage the light beam and, if needed, is scanned.

If the system determines that the luminaire is producing a modified light beam (step <NUM>), then the diffuser <NUM> is selected to engage the light beam (step <NUM>). The system then monitors the operation of the luminaire to determine whether the status of the luminaire may cause risk of damage to the diffuser <NUM> (step <NUM>). If so, the diffuser <NUM> is scanned as described with reference to <FIG> (step <NUM>). In determining a risk of damage, the system may consider, how long the diffuser <NUM> has been engaged, how long it is expected to be engaged given preprogramed lighting instructions, fixture temperature, ambient temperature, and/or other factors. In other embodiments, the logic can dictate that whenever the luminaire optical elements are repositioned to produce a modified light beam, the diffuser <NUM> is selected to engage the light beam and, if needed, is scanned.

<FIG> illustrates a remotely actuated reflector optical system <NUM> according to the disclosure, with an ellipsoidal reflector <NUM> in a first position. The optical system <NUM> includes a light source <NUM> having an emission point <NUM>, the ellipsoidal reflector <NUM> configured to reflect light emitted by the light source <NUM>, and motors <NUM> and <NUM> configured to move the ellipsoidal reflector <NUM> along its optical axis relative to the light source <NUM>. Other shaped reflectors are contemplated for other embodiments. In <FIG> the ellipsoidal reflector <NUM> is positioned relative to the light source <NUM> with the emission point <NUM> of light source <NUM> at the first focal point <NUM> of the ellipsoidal reflector <NUM>. In this first position, emitted light beam <NUM> is directed through aperture <NUM> with a slightly peaky beam distribution.

<FIG> illustrates the remotely actuated reflector optical system <NUM> of <FIG>, with the ellipsoidal reflector <NUM> in a second position. Motors <NUM> and <NUM> have been activated to move the ellipsoidal reflector <NUM> forward to position the emission point <NUM> of light source <NUM> behind the first focal point <NUM>. In this second position, emitted light beam <NUM> is directed through aperture <NUM> with a peakier distribution and increased hotspot.

<FIG> illustrates the remotely actuated reflector optical system <NUM> of <FIG>, with the ellipsoidal reflector <NUM> in a third position. Motors <NUM> and <NUM> have been activated to move the ellipsoidal reflector <NUM> rearwards to position the emission point <NUM> of light source <NUM> in front of the first focal point <NUM>. In this third position, emitted light beam <NUM> is directed through aperture <NUM> with a flatter distribution and reduced hotspot.

In other embodiments more or fewer than two motors may be used to control the position of the ellipsoidal reflector <NUM>. In still other embodiments, stepper motors, servo motors, linear actuators, or other suitable mechanical actuators may be used to move the ellipsoidal reflector <NUM>. The movement of the ellipsoidal reflector <NUM> in the preferred embodiment is continuous, providing multiple positions between an extreme forward position and an extreme rearward position. In other embodiments, the movement may be more stepwise with two or more positions selectable by an operator through the automated lighting system in which the luminaire is a part.

<FIG> presents a ray trace diagram of the optical system <NUM> of <FIG>, with the ellipsoidal reflector <NUM> in the first position. The emission point <NUM> of the light source <NUM> (for clarity, illustrated in <FIG> as an idealized point source) is positioned at the first focal point <NUM> of the ellipsoidal reflector <NUM>. Light is collected by the ellipsoidal reflector <NUM> and directed through the aperture <NUM> towards a second focal point <NUM>. The light beam <NUM> then continues towards further downstream optical elements (not shown) or towards a light target.

The light beam <NUM> may be directed through a series of optical devices such as a rotating gobo wheel containing multiple patterns or gobos, a static gobo wheel containing multiple patterns or gobos, an iris, color mixing systems utilizing subtractive color mixing flags, color wheels, framing shutters, graphic wheels, animation wheels, frost and diffusion filters, and beam shapers. The light beam <NUM> may then pass through an objective lens system, which may provide variable beam angle or zoom functionality, as well as the ability to focus on various components of the optical system before emerging as the required light beam.

The light beam <NUM> of light has a distribution <NUM>. With the light source and ellipsoidal reflector <NUM> in the configuration shown in <FIG>, the output light distribution <NUM> is produced with more light in the center than around the edges, and the intensity reduces gradually from the center to the edges of the beam. The shape of this light distribution may follow a bell curve shape and may be referred to as having a 'hotspot'. An operator may control the intensity of this hotspot and the flatness of the field by manually moving the light source of a prior art optical system along the optical axis to position its emission point in front of or behind the first focal point of the reflector during lamp installation.

However, as may also be seen in <FIG>, at locations in the light beam <NUM> that are nearer to or farther from the light source and ellipsoidal reflector <NUM> than the second focal point <NUM> (for example, at the aperture <NUM>), the intensity of the hotspot is diminished. The energy of the light beam <NUM> is spread over a wider diameter at these nearer/farther and the intensity at the center of the light beam <NUM> is less damaging than at the second focal point <NUM>.

Optical systems according to the disclosure provide remote control of the position of the reflector relative to the light source. As a result, field flatness becomes a dynamic operational control that an operator may use during a performance to dynamically adjust the beam to a desired profile at any moment. In one embodiment, the position of the light source is fixed and the ellipsoidal reflector may be moved backwards and forwards relative to that light source along its optical axis.

<FIG> presents a ray trace diagram of the optical system <NUM> of <FIG>, with the ellipsoidal reflector <NUM> in the second position. The ellipsoidal reflector <NUM> has been moved forward along the optical axis as shown by arrow <NUM> and the emission point <NUM> is positioned further back than the first focal point <NUM> of the ellipsoidal reflector <NUM>. Light beams still pass through aperture <NUM>, however they are not directed through the second focal point <NUM> of the ellipsoidal reflector <NUM>. Instead they are directed generally towards a point further along the optical axis than the second focal point <NUM>. In this second position of the ellipsoidal reflector <NUM>, the distribution <NUM> of the light beam <NUM> is less flat and the central hotspot is more pronounced than in the light beam <NUM> shown in <FIG>. Such a beam distribution may be advantageous for producing aerial beam effects.

<FIG> presents a ray trace diagram of the optical system <NUM> of <FIG>, with the ellipsoidal reflector <NUM> in the third position. The ellipsoidal reflector <NUM> has been moved rearward along the optical axis, as shown by arrow <NUM>, and the emission point <NUM> is positioned further forward than the first focal point <NUM> of the ellipsoidal reflector <NUM>. Light beams still pass through aperture <NUM>, however they are now directed generally towards a point closer along the optical axis than the first focal point <NUM>. In this third position of the ellipsoidal reflector <NUM>, the distribution <NUM> of the light beam <NUM> is flatter and the central hotspot is less pronounced, that is, the center of light beam <NUM> has a lower intensity than the center of light beam <NUM>, shown in <FIG>. Such a flat beam, with a reduced intensity hotspot, may be advantageous for projecting gobos, where a flat field may be desirable. As discussed above, a pronounced central hotspot may damage optical devices such as gobos, dichroic filters, prisms and other heat sensitive items. When such optical devices are in use, the flat field position of the reflector may be used to avoid heat-related damage. In some embodiments according to the disclosure, a control system automatically moves the reflector to the flat field position when an optical device that could be damaged by the hotspot is inserted into the beam.

<FIG>, and <FIG> illustrate an optical system <NUM> according to the disclosure where a position of the ellipsoidal reflector <NUM> may be based on an opening or closing of a variable iris <NUM> to provide a desired amount or characteristic of light through the iris <NUM>. <FIG> illustrates an optical system <NUM> according to the disclosure with a ellipsoidal reflector <NUM> and an iris <NUM> in a first configuration. The iris <NUM> is mounted to a bulkhead <NUM>. The ellipsoidal reflector <NUM> is positioned with the emission point <NUM> of the light source <NUM> at the first focal point <NUM> of the ellipsoidal reflector <NUM>. In this configuration, light beam <NUM> is directed through the iris <NUM> with a slightly peaky distribution <NUM>. As described with reference to <FIG>, the iris <NUM> is located closer to the light source <NUM> and the ellipsoidal reflector <NUM> than the second focus of the ellipsoidal reflector <NUM>, and the energy of the light beam <NUM> is spread across a larger area at the iris <NUM> than at the second focus of the ellipsoidal reflector <NUM>.

<FIG> illustrates the optical system <NUM> of <FIG> with the ellipsoidal reflector <NUM> and variable iris <NUM> in a second configuration. The iris <NUM> has been stopped down to a smaller size, producing a modified beam with a smaller diameter. If the configuration of light source <NUM> and ellipsoidal reflector <NUM> were left unchanged from the first configuration, then a large amount of light from the light source <NUM> and ellipsoidal reflector <NUM> would impact on the iris <NUM> and not pass through the smaller central aperture. However, as shown in <FIG>, motors <NUM> and <NUM> are activated in a first direction and ellipsoidal reflector <NUM> is moved forwards. In this configuration of the ellipsoidal reflector <NUM>, the emission point <NUM> of the light source <NUM> is positioned behind the first focal point <NUM> of the ellipsoidal reflector <NUM>. In this second configuration, light is directed in a narrower beam with more light passing through the center of the beam (an increased hotspot <NUM>) and an increased amount of light passes through the iris <NUM>.

<FIG> illustrates the optical system <NUM> of <FIG> with the ellipsoidal reflector <NUM> and the variable iris <NUM> in a third configuration. The iris <NUM> has been opened up to a larger size. If the configuration of light source <NUM> and ellipsoidal reflector <NUM> were left unchanged from the first configuration, then the outside edge of the aperture in the iris <NUM> would be illuminated at a low level. However, motors <NUM> and <NUM> are activated in a second direction and ellipsoidal reflector <NUM> is moved rearwards so that the emission point <NUM> of the light source <NUM> is positioned in front of the first focal point <NUM> of the ellipsoidal reflector <NUM>. In this third configuration, light is directed in a wider, flatter beam with light distributed (<NUM>) across the whole aperture in the iris <NUM>, and an increased amount of light passes through the outside edge of the aperture in the iris <NUM>.

The iris <NUM> provides a variable aperture. In other embodiments, a variable aperture may be provided by a gobo wheel having gobos with apertures of differing diameters.

In a further embodiment, the movement of motors <NUM> and <NUM> may be coupled to a motor actuating the iris <NUM>. In such an embodiment, as the iris <NUM> is opened and closed and its aperture size changes, the position of ellipsoidal reflector <NUM> is correspondingly adjusted to optimally position the ellipsoidal reflector106 relative to the light source <NUM> so that a maximal light output is directed through the aperture in the iris <NUM>. For example, as an operator reduces a size of the iris <NUM> aperture, motors <NUM> and <NUM> may be simultaneously actuated to move the ellipsoidal reflector <NUM> forwards, directing more light through the smaller aperture. Conversely, as an operator increases a size of the iris <NUM> aperture, motors <NUM> and <NUM> may be simultaneously actuated to move the ellipsoidal reflector <NUM> rearwards, to better fill the larger aperture.

The coupling of the movement of the iris <NUM> and the ellipsoidal reflector <NUM> may be any kind of coupling understood in the art. In some embodiments, the coupling could be a mechanical coupling, where a single motor or motors drives the movement of both the iris <NUM> and the ellipsoidal reflector <NUM> through linkages or gearing. In other embodiments, separate motors may be used to actuate the iris <NUM> and the ellipsoidal reflector <NUM>, and the separate motors are coupled electrically and fed with a common electrical signal. In still other embodiments, separate motors actuate the ellipsoidal reflector <NUM> and the iris <NUM>, firmware or software controls the motors independently, and the motors are coupled via a motor control system.

<FIG>, <FIG> show an optical system <NUM> according to the disclosure where a position of the ellipsoidal reflector <NUM> may be based on the insertion and removal of a gobo or other heat sensitive optical device into the light beam, to avoid damaging the gobo or optical device. <FIG> shows an optical system <NUM> according to the disclosure with a ellipsoidal reflector <NUM> and a gobo wheel <NUM> in a first configuration. The optical system <NUM> is shown in a peaked position where the light source <NUM> is positioned with its emission point <NUM> behind the first focal point <NUM> of the ellipsoidal reflector <NUM>. Light beam <NUM> is directed through an open aperture <NUM> of gobo wheel <NUM> and is thus an unmodified beam. Light beam <NUM> has a peaked beam distribution with a hotspot at <NUM>. As the open aperture <NUM> is in the beam there is no heat sensitive optical device into the light beam <NUM> and an operator may safely utilize the high output of the peaked beam.

<FIG> shows the optical system <NUM> with the ellipsoidal reflector <NUM> and the gobo wheel <NUM> in a second configuration. The gobo wheel <NUM> has been rotated to position a gobo <NUM> in the light beam <NUM>, producing a modified beam. As the position of the ellipsoidal reflector <NUM> remains unchanged from the position shown in <FIG>, the peaked light distribution of the light beam <NUM> with the pronounced hotspot <NUM> could damage the gobo <NUM> by local overheating at its center point <NUM>.

<FIG> shows the optical system <NUM> with the ellipsoidal reflector <NUM> and the gobo wheel <NUM> in a third configuration that may reduce or prevent such damage. Motors <NUM> and <NUM> have been activated to move ellipsoidal reflector <NUM> rearwards so that the emission point <NUM> of the light source <NUM> is positioned in front of the first focal point <NUM> of the ellipsoidal reflector <NUM>. In this position, light is directed in a wider, flatter beam with light distributed (<NUM>) across the whole of gobo <NUM>, reducing both the beam's hotspot and overheating at center point <NUM>.

As discussed with reference to <FIG> and <FIG>, a reduced hotspot intensity may also be found at locations in a light beam that are nearer to or farther from the light source than the second focal point of an ellipsoidal reflector, when the light beam is formed by a light source and ellipsoidal reflector in the configuration shown in <FIG> and <FIG>, e.g., the combined light source comprising light source <NUM> and reflector <NUM> as described with reference to <FIG>. Thus, in other embodiments of the disclosure, such a combined light source may be moved toward or away from a gobo or other optical device in the light beam to move the second focal point of the combined light source away from the optical device to reduce the effect of the beam's hotspot and the potential for overheating the optical device.

In some embodiments, movement of the ellipsoidal reflector <NUM> to the flat field position shown in <FIG> (or movement of occurs automatically by, for example, motor control firmware recognizing that the gobo wheel <NUM> has been rotated to position gobo <NUM> across the beam. In such embodiments, the ellipsoidal reflector <NUM> may automatically return to the forward, peaked position shown in <FIG> and <FIG> when the gobo wheel <NUM> is rotated back to the open aperture position and the gobo <NUM> is removed from the beam. In other embodiments, such control of the movement of the ellipsoidal reflector <NUM> to protect heat sensitive optical devices may be performed manually by an operator or by software in a remote control desk. An operator may also choose to override such protection and position the ellipsoidal reflector <NUM> manually.

In further embodiments, automatic movement of the ellipsoidal reflector <NUM> to the flat field position shown in <FIG> may be used to protect other thermally sensitive optical devices, such as dichroic filters, irises, graphic wheels, automation wheels, prisms, lenses, or other devices.

In some embodiments, automatic movement of the ellipsoidal reflector <NUM> to the flat field position shown in <FIG> may be used to protect the hot mirror <NUM> or diffuser <NUM> of the heat protection and compensation module <NUM>. A preset specified position for the ellipsoidal reflector <NUM> may be preprogrammed into the system of the automated luminaire and the ellipsoidal reflector <NUM> moved automatically to the preset position when the hot mirror <NUM> or diffuser <NUM> is moved into the beam. In some such embodiments, the preset position may be overwritten by an operator or by software in a remote control desk. A system according to the disclosure may provide separate, individual preset positions for the hot mirror <NUM> and the diffuser <NUM>.

In some embodiments, an operator is able to program whether the system automatically moves to the preset position of ellipsoidal reflector <NUM> or oscillates the hot mirror <NUM> or diffuser <NUM>, as described with reference to <FIG>. In such embodiments, the flow chart of <FIG> may be modified to permit the additional protection modes described herein.

In still other embodiments, the system may dictate that whenever the gobo wheel is moved into a non-open gobo position, a preset selection of diffuser <NUM>, ellipsoidal reflector <NUM> position, or combination of diffuser <NUM> and ellipsoidal reflector <NUM> position is automatically employed to protect the engaged gobo. A preset position for the ellipsoidal reflector <NUM> used alone may be different than a preset position for the combination of reflector position and homogenizer. For an individual gobo, or for a particular use of a gobo, an operator may specify whether the diffuser <NUM>, a ellipsoidal reflector <NUM> position, or a combination of diffuser <NUM> and ellipsoidal reflector <NUM> position is automatically engaged.

<FIG> presents a block diagram of a control system (or controller) <NUM> for an automated luminaire according to the disclosure. The control system <NUM> includes a processor <NUM> coupled to a memory <NUM>. The processor <NUM> is implemented by hardware and software. The processor <NUM> may be implemented as one or more CPU chips, cores (e.g., as a multi-core processor), field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), and digital signal processors (DSPs). The processor <NUM> is further electrically coupled to and in communication with a communication interface <NUM> and one or more actuators <NUM>.

The control system <NUM> is suitable for implementing processes, motor control, and other functionality as disclosed herein. Such processes, motor control, and other functionality may be implemented as instructions stored in the memory <NUM> and executed by the processor <NUM>.

The memory <NUM> comprises one or more disks, tape drives, and/or solid-state drives and may be used as an over-flow data storage device, to store programs when such programs are selected for execution, and to store instructions and data that are read during program execution. The memory <NUM> may be volatile and/or non-volatile and may be read-only memory (ROM), random access memory (RAM), ternary content-addressable memory (TCAM), and/or static random-access memory (SRAM).

<FIG> presents an isometric view of a second embodiment of a compensation module <NUM> according to the disclosure. <FIG> presents a side view of the compensation module <NUM> of <FIG>. In this embodiment, a diffuser <NUM> is mounted to an arm <NUM> that has an axis of rotation <NUM>. The diffuser <NUM> may be constructed of a single substrate as shown in <FIG>, or may comprise two or more layers. In some embodiments, the diffuser <NUM> may be a single substrate with a hot mirror coating on one of its surfaces so as to also act as a hot mirror as well as a diffuser. In other embodiments, the diffuser <NUM> may comprise two or more substrates, of which at least a first substrate is a diffuser or homogenizer and at least a second substrate is a hot mirror.

It will be understood that, in some embodiments, the compensation module <NUM> is used in the optical system <NUM> in place of the compensation module <NUM>. It will be understood that the technique of oscillating the diffuser <NUM> between first and second positions in the beam (as described with reference to <FIG>) may be used to reduce the effect of the heat energy of the beam on the diffuser <NUM>.

<FIG> presents a flow chart <NUM> of a second process of controlling a heat protection and homogenization system according to the disclosure. The flow chart <NUM> describes logic for protecting heat sensitive optical elements of an automated luminaire. The process described by the flow chart <NUM> may be performed by the control system described below with reference to <FIG>.

When the automated luminaire is on, the system monitors whether the luminaire is producing a modified light beam, for example, by placing a heat sensitive optical element in the light beam (step <NUM>). If the system determines that the luminaire is not producing a modified light beam (or if the beam is modified by an optical element that is not heat sensitive) the diffuser <NUM> is removed from the light beam (step <NUM>).

If the system determines that the luminaire is producing a modified light beam (step <NUM>), then the diffuser <NUM> is positioned in the light beam (step <NUM>). The system then monitors the operation of the luminaire to determine whether the status of the luminaire may cause risk of damage to the diffuser <NUM> (step <NUM>). If so, the diffuser <NUM> is scanned as described with reference to <FIG> (step <NUM>). In determining a risk of damage, the system may consider, how long the diffuser <NUM> has been engaged, how long it is expected to be engaged given preprogramed lighting instructions, fixture temperature, ambient temperature, and/or other factors. In other embodiments, the logic can dictate that whenever the luminaire optical elements are repositioned to produce a modified light beam, the diffuser <NUM> is selected to engage the light beam and, if needed, is scanned.

Claim 1:
An automated luminaire, comprising:
a combined light source (<NUM>, <NUM>) configured to produce an emitted light beam, the combined light source comprising a short arc discharge lamp (<NUM>) mounted in a fixed position within an ellipsoidal reflector (<NUM>) such that the arc is positioned near a first focus of the ellipsoidal reflector (<NUM>), the combined light source (<NUM>, <NUM>) having an optical axis and being configured to move along the optical axis;
a compensation module (<NUM>, <NUM>) optically coupled to the combined light source, the compensation module comprising a diffuser (<NUM>, <NUM>);
an optical device (<NUM>, <NUM>, <NUM>) configured to receive the emitted light beam and to produce one of a modified light beam and an unmodified light beam; and
a controller (<NUM>) configured to:
determine whether the optical device is producing the modified beam or the unmodified light beam and, in response to determining that the optical device is producing the modified light beam, move the combined light source (<NUM>, <NUM>) along the optical axis to a selected position relative to the optical device (<NUM>, <NUM>, <NUM>), the position selected to locate a second focus of the ellipsoidal reflector in front of or behind the optical device, and
the controller being further configured to move the combined light source along the optical axis to the selected position in response to the compensation module (<NUM>, <NUM>) positioning the diffuser in the emitted light beam.