Light fixture having improved movements and control method thereof

Abstract

A control method of a light fixture (1), wherein the light fixture (1) comprises: a housing (2), extending along a longitudinal axis (Z) and comprising a light source (4); actuators (15), configured to cause movements of the housing (2); a control unit (10), configured to control the actuators (15); a memory module (20), connected to the control unit (10); and an interface (25, 40). The control method comprises: storing, in the memory module (20), calibration data (D) of the movements of the housing (2); and making the calibration data (D) available to the outside of the light fixture (1) through the interface (25, 40).

Description

Cross-reference to related applications

[0001] This patent application claims priority from Italian patent application no. 102024000005521 filed on March 12, 2024, the entire disclosure of which is incorporated herein by reference.Technical field

[0002] The present invention relates to a light fixture, preferably a stage-light fixture, having improved movements and the control method thereof.Context

[0003] In the stage-lighting field, for example in the field of multi-source LED light fixtures, there is an increasing need to implement innovative and surprising stage effects. For said purpose, the light fixtures are typically moved according to rotations around two orthogonal axes, commonly known as PAN and TILT; each rotation is defined in a respective range of admissible angular positions of the light fixture (known as "stroke"), delimited by ends that are for example symmetrical relative to a central position (namely, a "zero" position) of the light fixture.

[0004] The movements of the light fixtures are preferably controlled remotely, for example through communications with a DMX protocol, starting from a control device. In practice, the control device receives as input (for example, from the user) data regarding the movements of one or more light fixtures, such as for example pairs of coordinates referred to respective PAN and TILT axes, and sends them to respective light fixtures according to the format of the chosen communication protocol. The data regarding the movements may also comprise, for example, coordinates referred to a zoom and / or focus longitudinal axis.

[0005] However, it is possible that the movements of a light fixture actually performed do not correspond to the movements desired by the user, mainly due to the accuracy with which the control device controls the respective light fixture. More specifically, the control of the light fixture may be influenced by differences that may exist between the reference stroke and the actual stroke of the rotation around at least one of the PAN and TILT axes. The control device, in fact, typically has rotation stroke values in its memory that refer to nominal data of the specific light fixture, declared by the manufacturer. The actual stroke values of the light fixture, however, often deviate from the reference stroke values, following calibrations performed for example by the installer or the user and necessary to compensate for the mechanical tolerances of the actuator devices of the light fixture movements.

[0006] A significant deviation of the reference stroke values from the actual stroke values may therefore have the consequence that the PAN and TILT coordinates actually processed by the light fixture deviate from those received as input by the control device, causing, for example, an error in the position of the beam emitted by the light fixture.Summary

[0007] It is therefore the object of the present invention to overcome or at least partially attenuate the disadvantages and limitations of the state of the art.

[0008] According to the present invention, a light fixture, preferably a stage-light fixture, and the control method thereof as defined in the attached claims are disclosed.Brief description of the Figures

[0009] For a better understanding of the present invention, preferred embodiments are disclosed, by way of non-limiting example, with reference to the attached drawings, wherein: Figure 1 schematically shows in a perspective view a light fixture according to an embodiment of the present invention; Figure 2 shows a simplified block diagram of the light fixture of Figure 1 and of a control device of the light fixture of Figure 1; Figure 3 shows a simplified block diagram relating to a control method of the light fixture of Figure 1; Figure 4 schematically shows in a diagram an example of calibration of a movement axis of the light fixture of Figure 1; and Figure 5 shows a simplified block diagram of a light fixture according to a different embodiment of the present invention and of a respective control device. Description of embodiments

[0010] In Figure 1, the reference number 1 denotes a stage-light fixture comprising a housing 2, a support 3, configured to support and move the housing 2, and a light source 4.

[0011] The housing 2 extends along a longitudinal axis Z and has a closed first end 7 and a second end 8, opposite the first end 7 along the longitudinal axis Z and provided with a projection opening 9. In the non-limiting example described and illustrated herein, the projection opening 9 has a substantially circular section and defines a circle-shaped projection area.

[0012] The housing 2 houses the light source 4, which comprises, in a non-limiting embodiment, a plurality of light modules 4a. The light modules 4a, for example identical in structure, are arranged side by side so as to occupy the projection area defined by the projection opening 9, in turn defining an emission surface of the light fixture 1. Each light module 4a comprises a respective output optics 4b. The output optics 4b are supported by a frame 5 coupled to the housing 2; the frame 5 is movable relative to the housing 2 along the longitudinal axis Z so as to allow zoom and / or focus adjustments of the light modules 4a.

[0013] The support 3 is configured to allow the housing 2 to rotate around two orthogonal axes, a PAN axis, and a TILT axis. In particular, the support 3 comprises a base 11 and a fork 12 coupled to the base 11 so as to rotate around the PAN axis. The fork 12 supports the housing 2 so as to rotate around the TILT axis.

[0014] Movements of the light fixture 1 therefore comprise, in a non-limiting manner, rotations of the housing 2 around the PAN and / or TILT axes and sliding of the frame 5 along the longitudinal axis Z. Said movements direct the beams emitted by the light modules 4a, allowing to obtain multiple scenic effects. In detail, the movements of the light fixture 1 are carried out by respective actuators 15 of the light fixture 1 (not shown separately in Figure 1). Even more in detail, the actuators 15 comprise PAN actuators 15a, TILT actuators 15b and zoom actuators 15c.

[0015] With reference also to Figure 2, the light fixture 1 also comprises a control unit 10, a memory module 20, connected to the control unit 10, and a communication interface 25. The control unit 10 is configured to control the actuators 15 and, more generally, manages to obtain the desired scenic effects (for example, by also regulating the intensity and the colour of the beams emitted by the light modules 4a). The memory module 20 stores and provides the control unit 10 with data useful for controlling the actuators 15 and, more generally, data useful to obtain the desired scenic effects (for example, specific sequences of scenic effects).

[0016] The memory module 20 stores, in particular, calibration data D comprising information regarding the possible movements of the light fixture 1. In detail, the calibration data D define the respective ranges of angular positions (around the PAN and TILT axes) and admissible positions (along the longitudinal axis Z) of the light fixture 1; said ranges are referred to as "strokes" in the following. In even more detail, the calibration data D comprise PAN calibration data D PAN , TILT calibration data D TILT and zoom calibration data D ZOOM . In practice, the control unit 10 manages the controlling of the actuators 15 based on the respective calibration data D. The calibration data D refer in particular to respective ends D 1 , D 2 of the strokes of the possible movements of the light fixture 1. As shown in Figure 4, referring for example to the stroke of the rotation around the TILT axis, the ends D 1 , D 2 are symmetrical relative to a central position (namely, a "zero" position) D 0 of the light fixture 1 around said axis. The control unit 10 therefore controls the actuators 15 so as to move the light fixture 1 within respective strokes delimited by respective ends D 1 , D 2 having as a reference the respective central position D 0 .

[0017] The calibration data D are saved in the memory module 20 following, for example, a factory calibration (performed by the manufacturer of the light fixture 1) or following the installation of the light fixture 1 (by the final user) in the scene to be lightened. More generally, the calibration data D of the light fixture 1 are saved in the memory module 20 whenever it is deemed necessary to correct the respective movement strokes of the light fixture 1 (step S1 of Figure 3): previous calibration data D can for example be replaced by subsequent calibration data D to compensate for possible electromechanical drifts of the actuators 15 during the average life of the light fixture 1.

[0018] The communication interface 25 of the light fixture 1 allows the connection of the light fixture 1 to a control device 30, which is configured to remotely control the movements of the light fixture 1 employing a communication channel, for example of the XLR type. In a non-limiting embodiment, the control device 30 is defined by a control console with which the user is able to manage, from a control room, the stage effects of one or more light fixtures such as the light fixture 1. For example, the control device 30 allows to obtain a system for automatically tracking the position of a person on the scene, so as to be constantly lightened by the light fixture 1. The control device 30 typically stores, in an internal memory module, nominal calibration data D T referring to respective light fixtures to be controlled; said nominal calibration data D T are typical data (namely, from the datasheet) of respective light fixtures, provided by the same manufacturers, and define theoretical strokes of the possible movements.

[0019] Always with reference to Figure 2, the control device 30 is configured to receive as input, for example from the user and through an input interface 31, movement data C referred to the angular position of the housing 2 and the position of the frame 5 of the light fixture 1; the movement data C define the desired movements of the light fixture 1 and are used by the control unit 10 to control the actuators 15 accordingly. For example, the movement data C may comprise a PAN coordinate C PAN , a TILT coordinate C TILT and a zoom coordinate C ZOOM , provided as a set of three values or as one of the possible combinations of the three values. The control device 30 may also receive as input sequences of movement data C that implement a specific sequence of stage effects. The input interface 31 is defined, for example, by an analog interface provided with commands and / or by a digital interface comprising a display and connections to an external computer.

[0020] The control device 30 sends, through a communication interface 35, commands to the control unit 10 of the light fixture 1 through communications in a preset protocol. Said commands comprise movement commands based on the movement data C received as input from the control device 30, in order to consequently move the light fixture 1, and may comprise corresponding values in the protocol used, for example DMX values. The communication interface 25 of the light fixture 1 receives the movement data C from the control device 30 and sends them to the control unit 10 for controlling the corresponding actuators 15.

[0021] According to an aspect of the present invention, the light fixture 1 is configured to make the calibration data D available to the outside. In particular, and with reference to Figure 3, the light fixture 1 provides the control device 30 with the calibration data D (step S2); in this way, the calibration data D can be used to replace the nominal calibration data D T referred to the light fixture 1 and initially stored in the control device 30 (step S3). The control device 30 of the present invention therefore processes the movement data C received as input based on the strokes defined for the movements of the light fixture 1 and, more specifically, based on the respective ends D 1 , D 2 set by saving the calibration data D in the light fixture 1 (step C1). The light fixture 1 is therefore controlled by the control device 30 in a manner that is always compliant and up-to-date relative to the calibration data D saved in the memory module 20; in this way, the movement data C received by the control unit 10 correspond to angular positions of the housing 2 and to positions of the frame 5 desired and correctly referred to the strokes set in the light fixture 1.

[0022] For clarity of understanding, in Figure 4 the stroke of the rotation around the TILT axis is also shown as defined by the nominal calibration data D T initially stored in the control device 30: as can be observed, the TILT coordinate C TILT input to the control device 30 would be processed incorrectly relative to the actual central position D 0 of the light fixture 1 if it were in reference to the nominal calibration data D T .

[0023] Hereinafter, some possible methods by which the light fixture 1 supplies the calibration data D to the control device 30 are described, by way of example (and therefore not to be considered in a limiting or exhaustive manner).

[0024] In the embodiment of Figure 2, the light fixture 1 is connected to the control device 30 through a communication channel XLR that uses a bidirectional protocol, for example an RDM protocol ("Remote Device Management", an evolution of the protocol DMX512); in particular, the communication interface 25 of the light fixture 1 is coupled to the communication interface 35 of the control device 30. Through said bidirectional protocol, the control device 30 controls the movements of the light fixture 1 and, according to priority logics determined by the protocol, the light fixture 1 can interact with the control device 30.

[0025] In detail, and also with reference to Figure 3, the control unit 10 is able to send on the communication channel XLR, through the communication interface 25 of the light fixture 1, the calibration data D that have been saved in the memory module 20 (step S2). The control device 30 acquires from the communication channel XLR, through the respective communication interface 35, the calibration data D of the light fixture 1. The control device 30 is then ready to calculate DMX values, corresponding to the movement data C received at input, according to the bidirectional protocol and based on the calibration data D (step C1). Finally, the control device 30 sends the DMX values corresponding to the movement data C to the control unit 10 of the light fixture 1 (step C2), thus obtaining the desired movements (step C3).

[0026] By employing a bidirectional communication protocol, it is possible to implement polling functions of the light fixture 1, for example to verify whether new calibration data D have been saved in the memory module 20 and to be able to update the same in the control device 30 for subsequent processing of the movement data C. More generally, according to an aspect of the present embodiment, the light fixture 1 sends - according to a preset protocol - updated calibration data D to the control device 30, so as to replace calibration data D already present in the control device 30.

[0027] Still with reference to Figure 2, the light fixture 1 is also provided with a position sensor 45 configured to detect absolute positions P of the light fixture 1 and, in particular, of the housing 2 (angular positions) and of the frame 5 (slidings). The position sensor 45 monitors the movements imparted by the actuators 15, for example employing dedicated mechano-optical sensors (for example, absolute encoders), and processes and sends data relating to the absolute positions P to the control unit 10. The control unit 10 is therefore able to send, on the communication channel XLR, also the absolute positions P of the light fixture 1 to the control device 30. The control device 30, based on the absolute positions P, can consequently correct the DMX values corresponding to the previously calculated movement data C and send updated DMX values back to the light fixture 1.

[0028] The control device 30 thus implements a feedback control of the movements of the light fixture 1, further reducing the command errors of the light fixture 1. In detail, the control device 30 is able to: compensate for possible deviations between the desired movements and those actually carried out; predict the trajectories of the movements in order to make the same available to the outside; activate alarm warnings based on detected deviations caused, for example, by wear of the mechanical components of the light fixture 1.

[0029] Figure 5 illustrates a different embodiment of the invention, in which the control device 30 acquires the calibration data D from the light fixture 1. Elements of Figure 5 that correspond to elements of Figure 2 are illustrated with the same reference numbers.

[0030] In the embodiment of Figure 5, the light fixture 1 comprises a display interface 40 that allows the calibration data D to be displayed outside of the light fixture 1. In detail, the control unit 10 collects the calibration data D saved in the memory module 20 and sends it to the display interface 40. For example, the display interface 40 is a display integrated into the light fixture 1, which makes the calibration data D available on request and / or in a dedicated menu according to a preset numeric format or in coded form (for example, a QR code).

[0031] The control device 30 then acquires the calibration data D made available by the display interface 40 of the light fixture 1, so that the movement data C can be processed according to the light fixture 1. The control device 30 acquires the calibration data D, for example, by user input through the input interface 31. Alternatively, the control device 30 acquires the calibration data D through a reading device configured to decode calibration data D in coded form and to send the decoded calibration data D to the input interface 31; said reading device is for example connected to the control device 30 in wireless mode and comprises an optical sensor capable of processing calibration data D in coded form, whenever available to the display interface 40 of the light fixture 1.

[0032] The control device 30 of the embodiment of Figure 5 is connected to the light fixture 1 through the communication channel XLR and sends commands to the control unit 10 of the light fixture 1 through communications in a unidirectional protocol (for example, a classic DMX protocol).

[0033] Also in the embodiment of Figure 5, the position sensor 45 sends data relating to the absolute positions P to the control unit 10, which are in turn sent to the display interface 40. The data relating to the absolute positions P are then also made available to the outside, for example in a format that shows the deviation - if any - relative to the movement data C of the desired movements; in this way, the control device 30 receives, through the input interface 31, the absolute positions P so that the control device 30 can make appropriate corrections on the DMX values corresponding to the desired movement data C, sending them back to the light fixture 1.

[0034] Ultimately, the control method of the present invention allows the movements of one or more stage-light fixtures to be controlled more accurately. In particular, by implementing the present method it is possible to control the light fixtures based on calibration data of respective movements which are always updated as coming directly from the light fixtures. The probability that the desired movements, controlled remotely through a control device such as a console, correspond to the movements actually performed is therefore significantly increased. The light fixtures controlled according to the method of the present invention are therefore generally more reliable.

[0035] Finally, it is clear that modifications and variations may be made to what has been described and illustrated here without thereby departing from the scope of the present invention, as defined in the attached claims.

[0036] For example, the control device may simultaneously control multiple light fixtures such as the one described employing the disclosed control method.

[0037] It is also intended that the light fixture may be controlled to implement additional movements relative to those described, thus obtaining the same advantages: for example, movements for framing systems, movements of additional components such as a gobo disk, a color disk, an animation disk, a rotation gobo disk. In general, the method of the present invention may be applied to those movements of the light fixtures that require calibration.

[0038] It is possible to use alternative bidirectional communication protocols to the RDM protocol: for example, it is possible to use the Art-Net, or RDMnet protocol. It is also possible to use communication channels of a different type from the communication channel XLR disclosed: for example, it is possible to use an ETHERNET communication channel, or it is possible to use a wireless DMX / RDM communication between the control device and the light fixture.

[0039] The calibration data of the single light fixture may come from a source other than a calibration performed by an external user: for example, the light fixture may store calibration data generated by a feedback control of the actuators of the movements, detecting any drifts over time.

Claims

1. A light fixture (1) comprising: - a housing (2), extending along a longitudinal axis (Z) and comprising a light source (4); - actuators (15), configured to cause movements of the housing (2); - a control unit (10), configured to control the actuators (15); - a memory module (20), connected to the control unit (10), containing calibration data (D) of the movements of the housing (2); and - an interface (25, 40), wherein the control unit (10) is configured to control the actuators (15) based on the calibration data (D), and to make the calibration data (D) available to the outside of the light fixture (1) through the interface (25, 40).

2. The light fixture (1) according to claim 1, wherein the movements of the housing (2) comprise rotations around at least one of a first axis (PAN) and a second axis (TILT), the first axis (PAN) and the second axis (TILT) being perpendicular to one another and perpendicular to the longitudinal axis (Z).

3. The light fixture (1) according to the preceding claim, further comprising a base (11) and a fork (12), wherein the fork (12) is coupled to the base (11) in a rotatable manner around the first axis (PAN), and wherein the fork (12) supports the housing (2) in a rotatable manner around the second axis (TILT).

4. The light fixture (1) according to any one of the preceding claims, further comprising a frame (5) slidably coupled to the housing (2) along the longitudinal axis (Z) and supporting the light source (4), wherein the actuators (15) are configured to move the frame (5) relative to the housing (2) along the longitudinal axis (Z).

5. The light fixture (1) according to any one of the preceding claims, wherein the calibration data (D) define respective strokes of the movements of the housing (2), and wherein the strokes are delimited by respective ends (D1, D2) and comprise a respective central position (D0).

6. The light fixture (1) according to any one of the preceding claims, wherein the interface (25, 40) comprises a communication interface (25), connected to the control unit (10), configured to provide the calibration data (D) on a communication channel (XLR).

7. The light fixture (1) according to any one of the preceding claims, wherein the interface (25, 40) comprises a display interface (40), connected to the control unit (10), configured to allow the display of the calibration data (D) outside of the light fixture (1).

8. The light fixture (1) according to any one of the preceding claims, further comprising a position sensor (45), connected to the control unit (10), configured to detect absolute positions (P) of the housing (2), wherein the control unit (10) is further configured to make the absolute positions (P) of the housing (2) available to the outside of the light fixture (1) through the interface (25, 40).

9. A control system comprising: - at least one light fixture (1) according to any one of the claims from 1 to 8; and - a control device (30), connected to the at least one light fixture (1) through a communication channel (XLR), configured to remotely control movements of the housing (2) of the at least one light fixture (1), wherein the control device (30) is further configured to acquire the respective calibration data (D) from the at least one light fixture (1).

10. The control system according to the preceding claim depending on claim 6, wherein the control device (30) is configured to acquire the calibration data (D) from the communication channel (XLR) according to a bidirectional communication protocol.

11. A control method of a light fixture (1), the light fixture (1) comprising: - a housing (2), extending along a longitudinal axis (Z) and comprising a light source (4); - actuators (15), configured to cause movements of the housing (2); - a control unit (10), configured to control the actuators (15); - a memory module (20), connected to the control unit (10); and - an interface (25, 40), the control method comprising: - storing, in the memory module (20), calibration data (D) of the movements of the housing (2); and - making the calibration data (D) available to the outside of the light fixture (1) through the interface (25, 40).

12. The control method according to claim 11, wherein the movements of the housing (2) comprise rotations around at least one of a first axis (PAN) and a second axis (TILT), the first axis (PAN) and the second axis (TILT) being perpendicular to one another and perpendicular to the longitudinal axis (Z).

13. The control method according to claim 11 or 12, comprising: - remotely acquiring the calibration data (D) from the control unit (10); - receiving movement data (C), corresponding to desired movements of the housing (2) of the light fixture (1); and - remotely control the movements of the housing (2) based on the movement data (C) and on the calibration data (D).

14. The control method according to claim 13, wherein remotely acquiring the calibration data (D) comprises: - sending, by the control unit (10) of the light fixture (1), the calibration data (D) to a remote-control device (30) on a communication channel (XLR) according to a bidirectional communication protocol; and - storing the calibration data (D) in the remote-control device (30).

15. The control method according to claim 13 or 14, wherein remotely control comprises: - providing movement commands, according to a communication protocol, based on the calibration data (D) and on the movement data (C); and - sending, on a communication channel (XLR), the movement commands to the control unit (10) of the light fixture (1).

16. A control system comprising: - at least one light fixture (1) according to any one of the claims from 1 to 8; and - a control device (30), connected to the at least one light fixture (1) through a communication channel (XLR), configured to remotely control movements of the housing (2) of the at least one light fixture (1) employing a control method according to any of the claims from 11 to 15.

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