A LIGHT BEAM EMITTING DEVICE

Abstract: A light beam emitting device is adapted for mounting on a conventional spot light and has a mirror (40) which may be panned and tilted to direct the spot light beam. A cage (18) surrounding the mirror contains coloured filters which may be rotated relative to the mirror to effect colour changes.

Description: A LIGHT BEAM EMITTING DEVICE This invention relates to a light beam emitting device, and in an important example to a moving spot light for stage or other entertainment use. British Patent Specification 2106233A discloses an entertainments moving spot device, in which a mirror is pannable and tiltable relative to a light source, in a reversible and angular-velocity-adjustable manner, to reflect a light beam therefrom. However, there is no provision for colour change. According to one aspect of the present invention, there is provided a light beam emitting device, comprising a reflector for reflecting light, in the form of a beam, from a light source; filter support means for supporting colour filters of different colours; drive means for displacing the reflector relative to the light source to alter the direction of the reflected beam and for displacing the filter support means relative to the reflector to cause the light to pass through different ones of the filters and control means arranged to control the drive means to produce a light beam of a selected colour in a selected direction. Such provision of a colour-change arrangement is particularly advantageous in the field of entertainment. In order that the invention may be clearly understood and readily carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:- Figure 1 shows an axial sectional view through a first version of a light-beam emitting device according to the invention, Figure 2 shows an axial sectional view through a second version of the device according to the invention, Figure 3 shows electrical control circuitry of the device shown in Figure 1, and Figure 4 shows further electrical control circuitry of the device shown in Figure 1. Referring to Figure 1, the light beam emitting device shown generally at 10 comprises an annular support plate 12 which is designed to be removably inserted into the front ost of a series of slots conventionally provided on spot lights for holding colour filters. A cylindrical wire mesh frame 14 is secured to the support plate and carries at its opposite end a dished end cover 16. Items 12, 14 and 16 all have a light-absorption finish. There is arranged co-axially and inwardly of the wire mesh cylinder 14, a cage 18 in the form of a pair of wire mesh cylinders - 17,19 which are co-axial with each other and define between them a narrow, annular gap 20. The gap 20 is divided into four equal, arcuate segments by reinforcing-and-dividing members 22. Three of the segments receive respective colour filters 24, which may be red, yellow or green, respectively. The filters can be replaced by filters of other colours or indeed by other transmissive light conditioning means such as masks or gratings. The members 17 and 19 are fixed, at their ends remote from the support plate 12, to the outer periphery of a co-axial dish 26. Fixed co-axially and centrally to the dish 26 is a panning gear wheel 28 which meshes with a pinion 30. The pinion 30 is carried on the output shaft of a panning and colour drive motor 32. Extending co-axially through the gear wheel 28 is a hollow shaft 34 to the end of which nearer the support plate is fixed a TJ- shaped bracket 36. The hollow shaft 34 is journalled in bearing 38. An oval-shaped plane mirror 40 is fixed centrally to a mount 42 which is tumably mounted on the bracket 36 by way of a pivot 44 perpendicular to the panning axis. The mount 42 is connected to a link 46 by way of a pivot 48 parallel to, but spaced from, the pivot 44* The link 46 is connected to a bush 50 by way of a pivot 52 parallel to the pivots 44 and 48, the bush 50 being mounted on a rod 54 which extends through the hollow shaft 34 so as to be turnable relative thereto but axially fixed relative thereto. Fixed to the shaft 34 perpendicular thereto is a disc 56, which is provided with locking means serving to lock together the shaft 34 (and thereby the mirror) and the gear wheel 28 (and thereby the cage 18 and filters 24. It will be appreciated that in the locked condition, rotation of pinion 30 through drive motor 32 will cause panning of the mirror with the filter cage remaining in register to ensure unchanging colour. To effect a colour change, the drive motor is actuated with the mirror unlocked from the filter cage, as will be described hereinafter. The locking means on the disc 56 comprises a leaf spring 58 of which a radially inner end is fixed to the disc 56 and a radially outer end is engagable by the armature of a solenoid 60. In the locked position shown in the drawing, a dog 62 carried at the outer end of the leaf spring, extends through an apeture in the disc 56 and engages a recess 64 in the gear wheel 28. As the solenoid 60 is actuated, the dog is withdrawn from the recess in the gear wheel, to enable the colour filters to be panned relative to the mirror. The recess 64 is one of four such holes in the gear wheel 28 distributed equi-angularly about the panning axis. A tilting motor 69 (not seen in Figure 1 ) operates through a driven disc 68, eccentric pin 70 and cross head 72 to reciprocate rod 54« This motion, as in the above mentioned prior patent, , effects tilting of the mirror about pivot axis 44 through the action of link 46. Arranged adjacent the disc 68 is a microswitch 74 which co¬ operates with a single protrusion 76 on the periphery of the disc to indicate the presence of the disc in a "home * , i.e. reference, position of tilt of the mirror. Similarly, the disc 56 carries a single protrusion 78 for co-operating with a microswitch 79 (not seen in Figure 1 ) to indicate the arrival of the disc 56 in a "home", i.e. reference, position of pan of the mirror. Arranged in a row in an axial plane of the device and adjacent the dish 26 are four microswitches 80 to 83 » which are arranged to co-operate with respective protrusions, of which two are seen and referenced 86 and 88, which are equi-angularly arranged around the dish 26 and which, when the dish 26 rotates about the panning axis, move in respective co¬ axial circles. These microswitches 80 to 83 indicate alignment of the respective four segments of the gap 20 with a reference position of the cage 18 relative to the cylinder 14 , and thus whether the light beam from the mirror will be transmitted through a red, yellow or green, filter, or through no filter to give white light. The device shown in Figure 1 is particularly suitable for manual remote control. The device shown in Figure 2 is more suited to control by a microprocessor. The device of Figure 2 differs from that of Figure 1 principally in that the mirror tilting and panning drives and the colour changing drive are stepping motors which are computer- controlled. Components which remain, unchanged, or essentially unchanged, from Figure 1 have the same reference numerals and will not be described. A reversible, stepping, colour-change motor 100 drives stepwise a worm 102 meshing with a toothed wheel 104 co-axial with the device. The wheel 104 is fixed to a colour-change shaft 106 which is rotatably mounted in the bearing 38 and which is fixed for rotation with the dish 26. A reversible, stepping, mirror panning motor 108 drives stepwise a worm 110 meshing with a toothed wheel 112 fixed to the shaft 34, which extends within the shaft 106 and is rotatable relative thereto. A reversible, stepping, mirror-tilted motor (not shown), drives the eccentric pin 70 engaging crosshead 72. -It will be appreciated by the skilled man that the pan, tilt and colour change stepping motors can be controlled through a microprocessor either to assume selected positions input by the user or to follow a programed sequence of moves. Figure 3 shows an example of electrical circuitry which can be used in manual joy-stick remote control of the device of Figure 1. The joy-stick operates the respective taps of a panning potentiometer 200 and a tilting potentiometer 202, each of which is connected between the +15 volts line and the -15 volts line. Arranged in parallel with the potentiometers 200 and 202 are respective panning and tilting trim potentiometers 204 and 206 allowing pre-adjustment of the potentiometers 200 and 202, respectively. The outputs from the potentiometers 200 and 202 are fed to respective amplifiers 208 and 210. The outputs from the amplifiers 208 and 210 are taken directly to respective "fast" fixed contacts of ganged switches 212 and 214. These switches have respective "off" fixed contacts and respective "slow" fixed contacts, which latter are supplied from the amplifiers 208 and 210 via voltage-averaging circuits 216 and 218. The outputs from the switches 212 and 214 are fed to respective amplifying and driving circuits 220 and 222. A home drive circuit 221 is also provided including two ganged switches 224 and 226 having respective "home" fixed contacts; "normal" contacts; and "stop at home" contacts . The switches 224 and 226 are manually operated, as are the switches 212 and 214- In the "off" conditions of the switches 212 and 214, the joy-stick cannot control the motors . In the "fast" conditions of those switches, the motors drive in a "fast" mode. Similarly, in the "slow" conditions of the switches, the motors drive in a "slow" mode through the effect of the voltage averaging circuits 216 and 218. With the switches 224 and 226 in their "home" condition, the motors are supplied directly with +15 volts and move the mirror quickly toward the "home" tilt position and move the colour filters and thus the mirror rapidly towards the "home" pan position. In the "normal" condition of the switches 224 and 226, the home drive circuit has no influence on the operation of the motors . In the "stop at home" condition of the switches 224 and 226, the circuit prevents the motors from moving the mirror and the colour filters from the "home" positions. The circuit 220 is connected to a "tilt" terminal 228, the home circuit 221 to a "home" terminal 230, and the circuit 222 to a "pan" terminal 232. There is in addition a common grounded terminal 234. Assuming that the switches 212 and 21 are in either the "fast" condition or the "slow" condition and the switches 224 and 226 are in the "normal" condition, movement of the joy-stick to move the tap of the potentiometer in one direction from its zero volts position will produce either fast or slow operation of the panning motor, and thus of the cage and the mirror, in one sense, whereas displacement of the tap in the opposite direction from its zero volts position will produce operation of the motor and thus of the cage and the mirror in the other sense. Similarly, control of the tilting of the mirror is achieved by operating the joy-stick to move the tap of the portentiometer in one or the other direction from its zero volts position. Of course, movement of the joy-stick to produce simultaneous movement of the taps of the potentiometers produces corresponding simultaneous operation of the motors. Referring to Figure 4, it can be seen that the tilting motor 69 is connected across the terminals 232 and 234 , with the interposition, of a switch ST of a relay RLT. Moreover, the panning motor 32 is connected across the terminals 234 and 228 with the interposition of a switch SC2 and one switch SP2 of a pair of ganged switches SPl and SP2 of a relay RLP. When the switches SC2, SPl and SP2 are in the positions shown in Figure 4, the motor can be energised by way of the terminals, under the control of the joy-stick. With the switch SC2 remaining in the position shown and the switches SPl and SP2 moved into their non-illustrated positions, the motor cannot be energised, but the terminal 228 is connected via the switch SPl and the solenoid 60 through two diodes to the solenoid 338 of a rotary solenoid switch 339• The solenoid 338 is connected to a negative terminal 340 of a pair of negative and positive terminals 340 and 341. If, in this condition, the switch SC2 is changed to its non- illustrated position, then the terminal 228 is connected via one of the icroswitches 80 to 83, in this case the "yellow" microswitch 81 , and the switch 339 to the terminal 234 • A relay RLC is connected between the solenoid 60 and the moving contact of the switch 339 ' The relay RLC has the switches SCI and SC2. Connected to the positive terminal 341 is a manually-operated, rotary, wiper switch 342 - 346 including a wiper 342 and "red", "yellow", "green" and "white" fixed contacts 343, 344, 345 and 346 respectively. The wiper 342 rests in the gaps between the contacts, but provides an electrical pulse as it passes over the contacts. Each pulse is passed through a momentary action switch 347, one diode, and the solenoid 338 , to the terminal 340, thereby to advance the switch 339 from one contact to the next of its "red", "yellow", "green" and "white" fixed contacts, respectively, which are connected to the respective micro-switches 80 to 83• The switch 347 is normally held open by a spring, but, when manually held closed against the action of the spring, allows adjustment of the switch 342 relative to the switch 339. The items 340- 347, are contained in a controller box which is remote from the rest of the circuit and connected thereto by a cable. In normal operation, the joy-stick controls the motors 32 and 69 by way of the terminals, the switch SP2, the switch SC2, and the terminal 234, and by way of the terminal 232, the switch ST, and the terminal 234 respectively. In order to disengage the mirror from the cage, to allow adjustment of the cage to change beam colour, let it be assumed that the colour is to be changed from yellow to green, in which case the micro-switches 80, 82 and 83 are all closed and the micro-switch 81 is open. The operator releases the joy-stick, so that the mirror and the cage are now stationary. The operator now operates the switches 224 and 226 from the "normal" contacts to the "home" contacts, which causes the motors 32 and 69 to drive to the "home" positions, in which the micro-switches 74 and 79 are closed, the relays RLP and RLT therefore energised and the switches SPl, SP2 and ST moved to their non-illustrated positions. The solenoid 60 is thereby energised via the terminal 228, the switch SPl, the diodes , the solenoid 338 and the terminal 340, to disengage the dog from the gear wheel, so that the cage is now free to pan relative to the mirror. The operator then moves the wiper 342 from between the contacts 344 and 345 to its rest position between the contacts 345 and 346 . A pulse is therefore transmitted from the terminal 341 via the contact 345 and the solenoid 338 to the terminal 340 , to turn the switch 339 to its "green" condition. Thereby, the relay RLC is energised via the terminal 335, the switch SPl, the micro¬ switch 82 , the switch 339 , the diodes, the solenoid 338 and the terminal340 to close the switch SCI and to change the switch SC2 from the position shown into its non-illustrated position. With the switch SCI closed, the solenoid 60 and the relay RLC are energised from the terminal to the terminal 335 via the diode and the switch SCI. The motor 32 can be now energised, via the terminal 335, the switch SPl, the micro-switch 82, the switch 339, the switch SC2 and the terminal 234, by operation of the joy-stick, to pan the cage relative to the mirror. When the protrusion 78 reaches the micro-switch 79, it opens the same to de-energise the motor, and to de-energise the relay RLC to open the switch SCI and to return the switch SC2 to the position shown, the solenoid 60 remaining energised via the solenoid 338. Operation of the switches to their "normal" contacts de-energises the relays RLP and RLT and thus causes the switches ST and SPl and SP2 to return to the positions shown in. Figure 4, so that the solenoid 60 is de-energised and the dog re-engages with the .gear wheel under the action of the spring. As the joy-stick is operated to move the motors from their home conditions, the micro-switches 74 and automatically open. ' The light-emitting devices shown in Figures 1 and 2 and the circuits shown in Figures 3 and 4 are, of course, readily usable in embodiments in which the light-emitting device is incorporated in a spot-light, either with no modification in the case of the circuits, or with little modification in the case of the devices. It should be understood that this invention has been described by way of example only and a great number of modifications may be made without departing from the scope of the invention. Thus the described filters could be made of any convenient substance and, if desired, combined in a single drum in which the colour changes continuously in the circumferential direction. More complicated visual effects could be achieved with two coaxial filter cages or drums. This may contain different sets of colour filters but, more usefully, one would contain colour filters and the other such light conditioning means as masks or patterned transparencies. Although it is not preferred, the mirror could be replaced by a fixed light source to give colour change without beam control.

Claims: CLAIMS 1. A light beam emitting device, comprising a reflector for reflecting light, in the form of a beam, from a light source; filter support means for supporting colour filters of different colours; drive means for displacing the reflector relative to the light source to alter the direction of the reflected beam and for displacing the filter support means relative to the reflector to cause the light to pass through different ones of the filters and control means arranged to control the drive means to produce a light beam of a selected colour in a selected direction. 2. A device according to Claim 1, wherein the filter support means substantially surrounds the reflector. 3« A device according to Claim 1 or Claim 2, wherein the drive means is adapted to pan and to tilt the reflector. 4. A device according to Claim 3, wherein the filter support means comprises a cylindrical framework co-axial with the panning axis of the reflector. 5- A device according to Claim 4, wherein the drive means is adapted to rotate the framework about its axis. 6. A device according to any one of the preceding claims, further comprising releasable locking means arranged to lock the filter support means in one of a number of discrete orientations relative to the reflector, said relative orientations being associated with different colours of the filters. 7. A device according to any one of the preceding claims, adapted to be fitted to a spotlight. 8. A device according to Claim 7, further comprising a flange adapted to be removably mounted in a colour filter slot of an existing spotlight. 9« A device according to any one of the preceding claims wherein said control means comprises a microprocessor. 10. A device according to any one of the preceding claims comprising a support mounted for rotation about a panning axis, said reflector being so mounted on the support as to be turnable relative thereto about an axis of tilting, wherein said drive means comprises a pan motor arranged to rotate said support about the panning axis and a tilt motor arranged to turn the reflector relative to said support about said tilting axis, said tilt motor driving said reflector through longitudinal displacement of an elongate member which extends through the support along the panning axis. 11. A light beam emitting device, comprising a light source adapted to produce a light beam; cylindrical support means surrounding the light source and arranged to support transmissive light conditioning means; drive means for rotating the support means about the cylindrical axis to bring different ones of said light conditioning means into register with the light beam and control means arranged to control the drive means. 12. A device according to Claim 11, further comprising beam drive means associated with the light source to effect panning of the light beam about said cylindrical axis, said control means including interlock means acting between said drive means and said beam drive means to ensure continuing registry between the beam and a selected one of the light conditioning means.

Inventors: WYNNE WILLSON PETER DAVID, WYNNE WILLSON, PETER, DAVID
Applicants: ECONOMAIR PANCAN LTD, ECONOMAIR PANCAN LIMITED
Application year: 1985
Main classification: F21P3
IPC codes: F21S10