EP2690357B1

EP2690357B1 - A lighting device

Info

Publication number: EP2690357B1
Application number: EP13168429.2A
Authority: EP
Inventors: Peter Johansen
Original assignee: SGM AS
Current assignee: SGM AS
Priority date: 2012-07-25
Filing date: 2013-05-20
Publication date: 2015-08-05
Anticipated expiration: 2033-05-20
Also published as: ITMO20120188A1; DK2690357T3; EP2690357A1

Description

The invention relates to a lighting device, for example to be used to illuminate a stage during a concert, a sport event, a convention or any other happening. The lighting device according to the invention can also be used for different purposes, such as for illuminating a building, a sport field, a monument or any other place. Lighting devices are known which comprise a light source that can be moved in any desired orientation, so that a light beam emitted by the light source can be directed along any desired direction. To this end, the light source is supported by a yoke and can be rotated about one or two axes by means of suitable motors associated to the yoke. A feedback system is provided for determining whether the motors have positioned the light source according to the desired orientation.
Known lighting devices have the drawback that providing a feedback system is quite expensive and significantly complicates the lighting device from a mechanical point of view. An example of a lightning device is described in the document WO 2007/030018 .
Furthermore, the feedback system provides information on the relative position that has been reached by the light source, i.e. the position of the light source in relation to certain mechanical parts of the lighting device. As a consequence, positioning correctly the light source may be difficult, especially if the yoke is not resting on a perfectly horizontal surface, but is hung to a frame at a height of several meters with a certain inclination angle.
An object of the invention is to improve known lighting devices, particularly lighting devices that can be positioned according to any desired orientation.
A further object is to provide a lighting device that can be easily controlled as far as its space position is concerned.
Another object is to control the position of a lighting device without using complicated feedback systems.
A further object is to provide a lighting device emitting a light beam that can be easily directed in any desired orientation, even if the lighting device is not resting on a perfectly horizontal surface.
According to the invention, there is provided a lighting device according to claim 1.
Owing to the measuring device, the position of the light source can be determined directly in an absolute reference frame, instead of being determined relative to a mechanical part of the lighting device as occurred in known devices. Any error occurring in known devices due to an imprecise positioning of the mechanical part which served as a reference for determining position of the light source is therefore avoided.
The light source can thus be correctly oriented even when the lighting device is not resting on a perfectly horizontal surface, but is, for example, suspended from a height of several meters.
Furthermore, since the position of the light source is determined in an absolute reference frame, there is no need to use feedback systems to enable the user to assess how the light source is actually inclined. This makes the lighting device less expensive and simplifies the mechanics thereof.
The invention will be better understood and carried out with reference to the attached drawings, which show some exemplificative and non limitative embodiments thereof, in which:

Figure 1 is a perspective view showing schematically a lighting device;
Figure 2 is a perspective view showing schematically a lighting device according to an alternative embodiment after installation.

Figure 1 shows a lighting device 1 that can be used to illuminate a stage during a public event such as a music concert, a sport meeting, a convention or the like. The lighting device can also be used to illuminate a building, for example a historical building, a public building or a hotel, or more generally to illuminate any other environment, such as a space in which a monument, a fountain or other is located.
The lighting device 1 can also be called a lighting fixture or a projector.
The lighting device 1 comprises a light source for emitting a light beam in a direction. The light source may be a lamp, for example a halogen lamp, a fluorescent lamp, a discharge lamp, or a light emission diode (LED). More than one light source can be used in a single lighting device, as is the case of a lighting device comprising a plurality of LEDs.
The light source is housed inside a housing 2, for example made of polymeric material. The housing 2 is provided with an opening 3 from which the light beam emitted by the light source may exit. The opening 3 may be provided with lenses or other optics in order to control the light beam.
The housing 2 is supported by a supporting arrangement 4 that can be rested on a horizontal surface or used to suspend the lighting device 1 from a fly system of the stage. The supporting arrangement 4 may comprise a base 5 which supports a movable supporting element 6. In the embodiment shown in Figure 1, the movable supporting element 6 is shaped as a yoke. However, other shapes of the movable supporting element 6 are also possible.
The base 6 houses a control unit for controlling operation of the lighting device 1. The user can interact with the control unit through a plurality of push-buttons, knobs and other control devices provided on the base 6.
The supporting element 6 can be rotated about a vertical axis Y relative to the base 5. This rotation of the supporting element 6 can be performed by means of a motor provided inside the base 5. The motor can be an electric motor, particularly a stepper motor.
By rotating the supporting element 6 about the vertical axis Y, the light source can accordingly be rotated about the vertical axis Y, in order to allow different points of the stage to be illuminated. This motion is referred to as "pan motion" of the light source.
The housing 2 can be rotated about a horizontal axis X relative to the supporting element 6. This can be done by means of a further motor of the lighting device 1, for example an electric motor such as a stepper motor. By rotating the housing 2, the light source can be rotated about the horizontal axis X, with a motion that can be referred to as a "tilt motion" of the light source.
The motors controlling rotation about the vertical axis Y and about the horizontal axis X act therefore as a positioning device that allows the light source to be positioned in any desired angle both about the horizontal axis X and about the vertical axis Y. The light beam emitted by the light source can thus be directed in any desired direction.
The lighting device 1 further comprises a measuring device for determining the position of the light source in an absolute reference frame. In other words, the measuring device is capable of determining the position of the light source in a reference frame which is fixed relative to the earth. The measuring device can thus provide information on the absolute position of the light source, i.e. on the position of the light source relative to the earth, and not on the position of the light source relative to a mechanical part of the lighting device, that could be moved relative to the earth.
The measuring device comprises a first measuring element 7 for determining - in the absolute reference frame - the angular position of the light source about one of the axes about which the light source is rotatable, for example about the horizontal axis X. The first measuring element 7 is mounted on a part of the lighting device 1 that can be rotated about the horizontal axis X together with the light source, for example on the housing 2.
The measuring device further comprises a second measuring element 8 for determining - in the absolute reference frame - the angular position of the light source about the other axis about which the light source is rotatable, i.e. about the vertical axis Y. The second measuring element 8 is mounted on a part of the lighting device 1 that can be rotated about the vertical axis Y by the same angle as the light source, and optionally that cannot be rotated about the horizontal axis. In the embodiment shown in Figure 1, the second measuring element 8 is provided on the movable supporting element 6.
In one embodiment, each of the measuring elements 7, 8 comprises a gyroscope, particularly an electronic gyroscope.
In one embodiment, each of the measuring elements 7, 8 comprises an accelerometer, which determines the position of the part of the lighting device to which it is associated on the basis of the position of this part relative to the gravity vector.
In any case, the measuring device is capable of determining the position of the light source by taking as a reference the gravity vector, or the horizon, or any other reference element the position of which relative to the earth cannot be changed. Thus, the measuring device gives the absolute position of the light source.
The measuring elements 7, 8 are connected to the control unit of the lighting device 1, so that information on the position of the light source can be transmitted to the control unit.
The control unit is also connected to the motors that rotate the light source about the horizontal axis X and about the vertical axis Y. The control unit controls these motors by deciding when the motors must be started, when they must be stopped and by which angle they must rotate the light source.
The control unit controls the motors which position the light source on the basis of information received from a user, for example on the basis of information that the user has inputted in a central control unit controlling a plurality of lighting devices.
Owing to the measuring device, the control unit of the lighting device 1 is capable of knowing continuously how the light source is positioned relative to the earth, which allows the control unit to determine when the desired position of the light source has been reached and stop the motors accordingly.
Since the control unit can monitor continuously the position of the light source, there is no need to provide complicated feedback systems allowing the control unit to determine whether a certain position has been reached or not.
Furthermore, owing to the measuring device, the position of the light source can be precisely determined and controlled independently of how the lighting device 1 is installed. Since the measuring device determines the position of the light source relative to the earth, the light source can be precisely positioned both when the lighting device 1 rests on a perfectly horizontal surface and when the lighting device 1 is somehow inclined, for example for being suspended from a tower or a bar of a fly system.
The measuring device can be successfully applied, in particular, to lighting devices 1 comprising so-called gobos. A gobo is a physical template that can be placed in front of the light source of the lighting device in order to control the shape of the emitted light beam. A gobo can be conformed as a piece of material with patterned holes through which light can pass, so that the light beam exiting the lighting device forms a desired pattern.
A lighting device may comprise a plurality of gobos, each corresponding to a different pattern. The user may select a certain gobo by acting, for example, on a keyboard of the lighting device. Thereafter, the control unit will cause the selected gobo to be brought in front of the light source, so that the desired pattern is obtained.
A plurality of lighting devices comprising respective gobos can be provided one adjacent the other, for example along a bar of a fly system of a stage.
In order to create special light effects, the control units of the lighting devices suspended from the bar can be programmed so that each lighting device generates a certain light pattern. The light patterns generated by each lighting device can also be varied according to a desired sequence, by changing the gobo which is arranged in front of the light source.
It may happen that adjacent lighting devices have been suspended to the bar in such a way that they are not perfectly aligned to one other from a mechanical point of view, for example if the base of a lighting device has been fixed to the bar with an inclination slightly different from the bases of the other lighting devices. If this occurs, there is a risk that the light patterns generated by the adjacent lighting devices are not correctly aligned and coordinated one with the other. A slight difference in the position of a lighting device relative to the bar may originate a significant misalignment in a light pattern projected on a wall at a distance of several meters from the lighting device. This may worsen appearance of the light effect created by the lighting devices.
By providing in each lighting device a measuring device capable of determining the position of the light source in an absolute reference frame, as previously disclosed with reference to Figure 1, it is possible to align the light patterns generated by each lighting device even when the bases of the lighting devices are fixed to the bar with different inclinations. This occurs because the measuring device determines the absolute position of the light source, which is independent of the inclination of the base relative to the bar. Owing to the measuring device, the control unit knows when the light beams emitted by the light sources are all aligned, for example along a horizontal direction.
By determining the absolute position of the light beam, the light beams emitted by a plurality of lighting devices can be precisely aligned over the horizon, thus allowing the lighting devices to form even complicated light patterns in a well coordinated manner.
The above applies not only to lighting devices suspended from a bar, but also to lighting devices resting on a horizontal surface or supported in any other way.
Figure 2 shows schematically a lighting device 11 that can be used to illuminate a building façade 20, for example a façade of a hotel, a historical building or the like. The lighting device 11 comprises a housing 12 that houses a plurality of light sources, which can be aligned in a horizontal direction. Each light source is configured to emit a light beam through a corresponding opening 13. Each light source can be of the LED type, in which case the lighting device 11 can also be called a LED bar.
The lighting device 11 further comprises a base 15, that can be suitable for being rested on the ground. The housing 12 is supported by the base 15, for example by being hinged to the base 15. The housing 12 may rotate relative to the base 15 about an axis, for example about a horizontal axis X1. By rotating the housing 12 about the horizontal axis X1, the height of the light beams emitted by the light sources can be varied.
In order to rotate the housing 12 about the horizontal axis X1, a motor can be provided, for example housed inside the base 15.
The lighting device 11 further comprises a control unit that can control the position of the housing 12 and hence modify the orientation of the light beams by acting on the motor.
A measuring device is also provided for determining the position of the light sources in an absolute reference frame. The measuring device can comprise a measuring element 17 provided, for example, on a part of the lighting device 11 fixed relative to the light source, such as on the housing 12.
In one embodiment, the measuring element 17 can comprise a gyroscope, particularly an electronic gyroscope.
In the alternative, the measuring element 17 could comprise an accelerometer, or any other device which is capable of determining absolute position of the light source.
The measuring element 17 can be so configured as to determine the angular position of the housing 12 about the horizontal axis X1 with reference, for example, to the vertical direction, i.e. to the direction identified by the gravity vector. The control unit can thus be continuously informed as to how the housing 12 is angularly positioned about the horizontal axis X1 taking as a reference the vertical direction.
If the control unit is instructed to displace the light sources housed in the housing 12 in a certain position, which is defined by an angle formed by the housing 12 relative to the vertical direction, the control unit can thus easily calculate by which angle the housing 12 must be rotated about the horizontal axis X1 so as to arrive at the desired position, taking into consideration which position is currently occupied by the housing 12, as determined by the measuring element 17.
In an embodiment, the lighting device 11, and particularly the direction of the light beams emitted by the light sources, can also be controlled remotely. For example, the lighting device 11 could comprise a GSM communication device that can communicate with a mobile phone, for example by SMS.
In this case, an operator could send an SMS to the lighting device 11 in order to instruct the control unit to position the light sources so that they emit light beams in a certain direction. When the GSM communication device of the lighting device 11 receives the SMS, the control unit deciphers the SMS and, starting from the current position of the housing 12 as determined by the measuring device, moves the housing 12 and hence the light sources in the desired position.
The control unit can be so configured as to send back an SMS to the mobile phone of the operator confirming that the light sources have been moved to the desired position.
The operator can thus control the lighting device 11 even from a very far location, not only by instructing the control unit to rotate the housing 12 in the desired position but also, optionally, to turn on and off the light sources.
In place of the GSM communication device, any other remote communication device, particularly of the wireless type, could be used by the operator to control the position of the lighting device remotely.
In any case, the measuring device allows the angular position of the light source about at least one axis to be determined in an absolute reference system and not based on the physical position of the base of the lighting device. The drawbacks present in known devices due to imprecision in installing the base or to the need of feedback systems are thus overcome.

Claims

A lighting device comprising a light source for emitting a light beam in order to illuminate an environment, a positioning device for changing orientation of the light source, so that the light beam can be emitted in a desired direction, wherein the lighting device (1; 11) further comprises a measuring device (7, 8; 17) for determining position of the light source in an absolute reference frame; characterized in that the measuring device (7, 8; 17) comprises a first measuring element (7; 17) for determining, in said absolute reference frame, the position of the light source about an axis (X; X1), the light source being rotatable about said axis (X; X1) by the positioning device and in that the measuring device (7, 8; 17) comprises a second measuring element (8) for determining, in said absolute reference frame, the position of the light source about a further axis (Y), the light source being rotatable about said further axis (Y) by the positioning device, wherein the first measuring element (7) is mounted on a part of the lightning device (1) that can be rotated about the axis (X) together with the light source the second measuring element (8) is mounted on a part of the lighting device (1) that can be rotated about the further axis (Y) by the same angle as the light source.
A lighting device according to claim 1, wherein the measuring device (7, 8; 17) comprises at least one gyroscope.
A lighting device according to claim 1 or 2, wherein the measuring device comprises at least one accelerometer.
A lighting device according to claim 1, wherein said axis (X; X1) is a horizontal axis.
A lighting device according to claim 1 or 4, wherein the measuring element (7; 17) is fixed relative to a housing (2; 12) provided in the lighting device (1; 11) for housing the light source.
A lighting device according to claim 1, wherein said further axis (Y) is a vertical axis.
A lighting device according to claim 5, wherein the further measuring element (8) is fixed relative to a mobile supporting element (6) that supports the housing (2), the mobile supporting element (6) being rotatable relative to a base (5) of the lighting device (2) by the positioning device, the supporting element (6) being optionally shaped as a yoke.
A lighting device according to any preceding claim, and further comprising a gobo positioned in front of the light source in order to shape the light beam emitted by the light source according to a preset pattern.
A lighting device according to any preceding claim, and further comprising a wireless communication device for receiving a signal from a remote control device, said signal containing information on the orientation of the light source, said wireless communication device being connected to a control unit of the lighting device (1; 11) so that the control unit can act on the positioning device to change the orientation of the light source in response to said signal.
A lighting device according to claim 9, wherein the wireless communication device is a GSM communication device and the signal is a SMS sent from a mobile phone.
A lighting device according to claim 9 or 10, wherein the wireless communication device is configured for sending a confirmation signal to the remote control device when the orientation of the light source has been changed in response to said signal.