WO1997008491A1

WO1997008491A1 - Motor-driven pan and tilt mirror coupled relative to a stage lamp

Info

Publication number: WO1997008491A1
Application number: PCT/US1996/013661
Authority: WO
Inventors: Warren I. Steadman; Jonathan C. Holt
Original assignee: Light & Sound Design
Priority date: 1995-08-24
Filing date: 1996-08-23
Publication date: 1997-03-06
Also published as: AU6901496A

Abstract

A stage lighting system including a high-speed pan and tilt mirror (200) mounted to a stage lamp (100) by a support brace (130), and driven by a motor (126) controlled by the stage lamp's internal motor control bus (106) so as to provide for high-speed scanning of the stage lamp's light beam.

Description

MOTOR-DRIVEN PAN AND TILT MIRROR COUPLED RELATIVE TO A STAGE LAMP

FIELD OF THE INVENTION This application describes a motor-driven stage lighting system and, more specifically, a motor-controlled pan and tilt mirror mounted at a position relative to a stage lamp which always stays the same relative to the stage lamp. This allows high-speed scanning of the stage lamp's light beam to create theatrical stage lighting effects.

BACKGROUND AND SUMMARY OF THE INVENTION

A satisfactory method for high-speed scanning of the light beam emanating from a stage lamp has presented a challenge to the stage lighting industry.

Currently used lighting systems include a substantial-size lamp and motor. The sheer weight of the lamp and its motor requires that substantial inertia be overcome by any element attempting to drive its movement. This inertia makes it practically impossible to start and stop the lamp quickly. Hence, certain high-speed stage lighting effects have been difficult to achieve.

One prior art solution has been to mount a motor-driven mirror on a truss near the lamp. The lamp is also preferably mounted on the same truss. Since the mirror has very low mass, it can be started and stopped very quickly. This arrangement requires, moreover, that the lamp be aimed at the mirror whenever mirror-driven effects are desired. The inventor recognized that the same problem occurs in the conventional mirror-driven lamp. Sometimes the lamp needs to move more quickly than possible because of the weight-induced inertia of the lamp.

In addition, complicated calculations are often required to determine exactly where to move the lamp to point the light beam from the lamp toward the location of the mirror.

This invention has an object to provide high- speed scanning of the stage lamp's light beam. This object is realized by attaching a motor-driven pan and tilt mirror relative to a mounting surface ofthe stage lamp by a rigid support brace. The brace positions the mirror assembly at a predetermined position relative to the stage lamp. The mirror can itself be panned and tilted to positions including a "stowed" position where it is out of the light beam, and a number of positions where it reflects the light beam. This allows the lamp to project light to the mirror in any position of the lamp, simply by tilting the mirror out of its stowed position.

As described above, in the truss mounted mirror system, the lamp needed to be adjusted in both pan and tilt dimensions to find the mirror. The present invention mounts the mirror to the lamp in a way such that the mirror follows the lamp in all positions of the lamp. This system reduce the amount of movement that the lamp needs to make to find the mirror at any given time and also substantially simplifies the necessary spatial calculations. This allows rapidly finding the mirror at all times. Once the lamp output is facing the mirror, the light beam will be shining thereon, and the mirror can be two-dimensionally moved to quickly scan the light beam.

The disclosed system uses a universal pivot joint which is motor driven, and is driven from a control bus for the controlling system that controls the light operation.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an view of the stage lamp and mirror assembly illustrating the attachment of the support brace to the assembly; the other end, and the alignment of the stage light beam to the location of the mirror;

Fig. 2 is a view of the stage lamp and mirror assembly;

Fig. 3 is a perspective view of the mirror assembly illustrating the mirror assembly attached to the support brace;

Fig. 4 is a block diagram of the electronics driving the mirror assembly;

Fig. 5 is a block diagram of a more sophisticated electronics system for driving the mirror assembly;

Fig. 6 is a flow chart describing operation of the processor of Fig. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed to stage lighting systems employing mirrors to facilitate scanning of light beams from stage lamps to create theatrical stage lighting effects. The present invention mounts a high-speed, motor-driven pan and tilt mirror to the lamp yoke or other mounting surface of the stage lamp by a support brace to facilitate high-speed scanning of the light beam.

The stage lamp and mirror assembly is shown in FIGS. 1 and 2. A movable stage lamp 100 is pivoted about yoke 102 to a support truss. As is conventional in such moving lights, the yoke includes two pivoting joints which allow the light to "pan" and "tilt". The term pan refers to the movement of the light element in the plane perpendicular to the paper, to scan the light beam horizontally across the target. The term "tilt" includes moving the light within the plane of the paper, essentially vertically relative to the stage. Yoke 102 is motor-driven, and this is conventionally carried out by a control element 106 which is contained within the mounting mechanism 104. Mounting mechanism 104 is conventionally located on the stage truss or the like to hold the lamp in place. Alternately, a separate mounting mechanism can be provided.

The lamp unit is controlled by electrical signals from a cable 110 which is connected to the controller 106. This wire 110 can include lamp signals in any desired format, including DNX, multi-parameter DNX or any other similar kind of time-division format, or simply in a control format such as our RS-232.

Figures 1 and 2 show drawings of the ICON (TM) unit available from Light and Sound

Design Ltd., Birmingham, England. This is the preferred lamp used according to the present invention.

The lamp body 120 can hence be panned and tilted using controlling motors which are located either in the yoke or in the lamp body itself. This is done under control of processing elements as well known in the art.

Yoke 102 is shown as a substantially rectangular element. It therefore has many flat surfaces thereon, all of which are suitable for mounting a support brace thereon. Support brace 130 is preferably mounted to one of these flat surfaces of the yoke.

A first mounting surface 140 of the support brace is preferably mounted to a first flat surface 131 of the yoke. Similarly, a second surface 142 of the support brace is mounted to a corresponding surface 132 on the other side of the yoke. It should be understood, however, that any surface of the lamp which moves along with the lamp could be used as an attachment surface. The surface used according to the present invention could be a surface which pans only, tilts only or one pans and tilts. Figures 1 and 2 show the surface being the yoke, show that surface 140 is attached to yoke surface 131 and brace surface 142 is attached to yoke surface 132. The support brace 130 positions the mirror assembly so as to place the mirror assembly at a predetermined position relative to the lens 118 of the stage lamp 100.

The mirror assembly as shown in perspective in Figure 3 illustrates mirror assembly 200 being mounted to attachment surface 116 of the support brace 134. Mirror mounting mechanism 120 includes universally-swivelling bracket 123 is mounted to a back i.e., non-reflective surface of mirror 124. Motor 126 drives the position of bracket 123 in x and y directions. Preferably bracket 123 is a so-called universal joint which is movable in x and y directions.

Controller 106 controls the lamp in the usual way, and also produces the information for driving the mirror also. The output of controller 106 is of course connected to associated processors 107 in the lamp. The output indicative of the proper controlling is also connected to a wire 125 that is connected along the bracket 132 to a controller interface 135.

Figure 4 shows a block diagram of the electronics driving the mirror assembly 200. Housing 400 is attached to support brace 122. The wires 125 can include control signals encoded thereon. In this example, the signals are encoded in RS-232 form. In the simplest form of this embodiment, shown in Figure 4 no specific processor is needed. Line receivers 402, 404 receive two pairs of wires, one pair includes x direction output 406. The other produces a y controlling output 408.

Motor assembly 126 includes an x motor 410 and y motor 420. These motors control respective positions in the x and y directions. The y motor 420 controls the y- directional pivoting of bracket 123. The x motor controls the x direction pivoting of bracket 123.

This simplistic system shown in Figure 4 requires that the controller 106 calculate all mirror control commands. A more sophisticated system is shown in Figure 5. Cable 125 carries an encoded indication of a desired position. Input module 135 receives and buffers this information and couples it to processing unit 500.

Bracket 123 also includes x and y encoders 160 which produce outputs indicating the current position. X encoder 502 records the specific position of the bracket in the x direction, and y encoder 504 reports the specific position of the bracket in the y direction. This information is reported to the processor 500. The processor also outputs signals to control the x motor 410 and y motor 420 which operate to move the bracket in x and y directions as in the previous embodiment.

The processor operates according to the flowchart of Figure 6. At step 600, the processor receives an x and y command and time which can be generated by the console. At step 602, the system obtains the current x, y position of the bracket from the encoders 502, 504. Step 604 calculates how far the motor needs to be moved to get to the desired x, y position by calculating x desired minus x current and y desired minus y current, dividing this delta position by the preferred motor speed V_n to obtain the necessary starting time. At the starting time T_s the motor is moved to the desired position.

Other functions are also possible, and are shown in the Figure 6 flowchart. Step 606 represents receiving an "over" command, meaning that the system is no longer in need of the movable mirror. At this point, the mirror needs to be moved to its stow position at step 608. One particularly preferred way of doing this is to properly define the coordinate system. The point 0, 0 can be defined as the stowed position where the mirror is completely out of the path of the light beam. Alternately, the maximum x and y position can be defined as stows. In either of these cases, no calculation is necessary when the operation command is "over".

Step 608 shows going to the stow position, which can be done by either calculating the position of stow, or by using one of the above two techniques.

It should be understood the time slicing can be carried out by these motors, using the processor, or ultimately x and y position can be calculated by the time slicing processor within the main unit.

Although only a few embodiments have been described in detail above, those having ordinary skill in the art will certainly understand that many modifications are possible in the preferred embodiment without departing from the teachings thereof.

All such modifications are intended to be encompassed within the following claims.

Claims

WHAT IS CLAIMED IS:

1. A movable light assembly, comprising: a light housing, housing a light producing source and control electronics therein, said control electronics including a controller which commands a position of said light having said light housing including a mounting structure adapted for mounting to a support, said light housing moveable to positions based on commands from said controller and having an outer surface attached to said housing which is also moved to said positions; a movable mirror assembly, including at least one axis of rotation, and including a motor for driving said movable mirror assembly over said at least one axis of rotation; a housing, holding said movable mirror assembly, said housing including an attachment surface thereon; a support brace, having a first portion attached to said outer surface of said light housing, and having a second portion attached to said attachment surface of said housing, said support brace always holding said housing of said mirror assembly at a specific position relative to said light housing; and an interface between the controller for said moving light and said motor, said interface providing a control signal to said motor.

2. An assembly as in claim 1 , wherein said interface includes a wire running from said controller of said moving light to said motor.

3. An assembly as in claim 2, wherein said controller further includes a processor, in said movable mirror assembly, said processor receiving a command from said controller in said moving light, and translating said command into a form to drive the motor.

4. An assembly as in claim 3, wherein there are two motors, respectively controlling x and y positioning of said movable mirror assembly.

5. An assembly as in claim 1 , wherein there are at least two motors, respectively controlling x and y positioning of said movable mirror assembly, and wherein said interface includes controls for both said x and y motors.

6. An assembly as in claim 1 , wherein said mirror includes at least a first position in which light projected from the lamp contact said mirror and is reflected by said mirror to a specific location, and the second, stowed position in said mirror is out of the path of light reflected by said lamp.

7. An assembly as in claim 1, wherein lamp is moved in pan and tilt directions by a yoke, and wherein said bracket is attached to an outside surface of said yoke.

8. An assembly as in claim 1 , further comprising a universal joint pivot movable in both directions, connected between a portion of said bracket and said moving mirror.

9. A method of mirror scanning, comprising: providing a moving light source which is capable of moving in at least pan and tilt directions; providing a moving mirror which is capable of moving in at least one direction; attaching said moving mirror to an outside surface of said light source at a distance therefrom, and in a location where said moving mirror can be moved to a stowed position where it is out of the projected path of light emanated from said light source, or a non-stowed position where it is in a moving path of said light, said mirror being capable of being moved into a path of said light in any pan or tilt position of said moving light source; moving said light source to a particular pan and tilt location; moving said mirror into a position that intersects a path of said light, so that said light is projected by a movement of said mirror to another location; and moving said mirror to x and y locations to effect a final position of said light source.