WO1995025246A2

WO1995025246A2 - Lamp fitting

Info

Publication number: WO1995025246A2
Application number: PCT/GB1995/000555
Authority: WO
Inventors: Andrew Terry Neal
Original assignee: MEGATAR Ltd
Current assignee: MEGATAR Ltd
Priority date: 1994-03-15
Filing date: 1995-03-15
Publication date: 1995-09-21
Anticipated expiration: 1996-09-15
Also published as: WO1995025246A3; AU1897195A

Abstract

A lamp fitting including a collar member (1) which can be fitted in, or over, a neck section (2) of a reflector (3) and to which a lamp can be mounted, said collar member (1) including a fitting for cooperating with the neck section (2) of the reflector (3) so as to allow variation in axial position of the reflector (3) in relation to the collar member (1). The lamp fitting may include a reflector (3).

Description

LAMP FITTING

The present invention relates to a fitting for locating a lamp in at least two positions in a lamp reflector, and to a lamp assembly comprising a non-parabolic reflector and variable focus lamp fitting.

In many applications, lamp reflector arrangements producing different beam angles and/or intensities are required to provide desired effects. However, in conventional lamp reflector arrangements, used for example in stage lighting, it is not possible to vary the beam angle and intensity as the fitting which houses the lamp is fixedly mounted to the reflector body. Thus, if a different beam angle and/or intensity is required the lamp reflector arrangement has to be replaced.

The present invention aims to provide a fitting for a lamp reflector, in particular a fitting in combination with a non-parabolic reflector, which allows a lamp to be located repeatedly and accurately in at least two positions in a reflector and thus- provide an output beam having at least two different beam angles and/or intensities.

Accordingly, the present invention provides a fitting for a lamp and reflector, which fitting comprises a collar member which can be fitted in, or over, a neck of a lamp reflector and to which a lamp can be mounted, said collar member including axially adjustable attachment means for cooperating with means on the neck of the reflector to allow variation in axial position of the reflector in relation to the collar member.

Preferably, said axially adjustable attachment means forms part of a slot and follower arrangement in which the follower rides in the slot, so that the relative position of the collar member and the neck of the reflector, which determines the position of the lamp in the reflector, is governed by the position of the follower in the slot.

Preferably, said collar member includes a lamp holder secured in a position axially relative to said collar member.

The invention also includes a collar member as aforesaid together with a reflector mounted to said collar member.

The present invention further provides a lamp assembly comprising a non-parabolic reflector and a variable focus lamp fitting.

Embodiments of the present invention will now be described hereinbelow by way of example only with reference to the accompanying drawings, in which:

Figure 1 is a side elevational view of a lamp fitting mounted on a lamp reflector (shown in cross section) in accordance with a first embodiment of the present invention;

Figure 2 is a plan sectional view taken along line A-A illustrated in Figure 1;

Figure 3 is a cross-sectional view of a parabolic lamp reflector;

Figure 4 is a side elevational view of an alternative collar member for use with the lamp fitting illustrated in Figure 1;

Figure 5 is a side elevational view of another alternative collar member for use with the lamp fitting illustrated in Figure 1;

Figure 6 is a side elevational view of a further alternative collar member for use with the lamp fitting illustrated in Figure 1; Figure 7 is a plan elevational view of a still further alternative collar member for use with the lamp fitting illustrated in Figure 1;

Figure 8 is a cross-sectional view along line B-B of the collar member illustrated in Figure 7 ;

Figure 9 is a cross-sectional view along line C-C of the collar member illustrated in Figure 7;

Figure 10 is a part plan elevational view of a lamp reflector adapted to receive the collar member illustrated in Figures 7 to 9;

Figure 11 is a first side elevational view of the neck section of the lamp reflector illustrated in Figure 10 (viewed along line D-D) ;

Figure 12 is a second side elevational view of the neck section of the lamp reflector illustrated in Figure 10 (viewed along line E-E) ;

Figure 13 is a plan elevational view of a spacer employed in conjunction with the collar member illustrated in Figures 7 to 9 ;

Figure 14 is a cross-sectional view along line F-F in Figure 13 ;

Figure 15 is a side elevational view of a lamp fitting mounted on a lamp reflector (part cut away) in accordance with a second embodiment of the present invention;

Figure 16 is an exploded view of the lamp fitting illustrated in Figure 15;

Figure 17 is a side elevational view of the assembly frame illustrated in Figures 15 and 16;

Figure 18 is an elevational view of the assembly frame illustrated in Figures 15 and 16 viewed from below;

Figure 19 is a plan elevational view of the collar member illustrated in Figures 15 and 16;

Figure 20 is a first side elevational view of the collar member illustrated in Figure 19 (viewed along line G-G) ; Figure 21 is a second side elevational view of the collar member illustrated in Figure 19 (viewed along line H-H) ;

Figure 22 illustrates a front view of a film lighting array in accordance with the present invention; and

Figure 23 illustrates in cross-section a single lamp unit of the lighting array of Figure 22.

Figures 1 and 2 illustrate a lamp fitting mounted on a lamp reflector 3 in accordance with a first embodiment of the present invention. A collar member 1 is mounted over a rear neck section 2 of the lamp reflector 3. The collar member 1 alternatively, however, could be adapted to fit within the neck 2 of the lamp reflector 3. The collar member 1 is preferably an interference fit with the neck section 2 of the lamp reflector 3 in order to more securely maintain the collar member 1 in position on the neck section 2 of the lamp reflector 3. A lamp holder 5, in which a lamp 6 is removably located, is mounted to the collar member 1. The position of the lamp 6 is thus fixed in relation to the collar member 1 and hence it is the axial position of the collar member 1 in relation to the neck 2 of the reflector 3 which determines the position of the lamp 6 in the reflector 3.

The lamp holder 5 is a known commercially available unit. Lamp holders are selected according to the type and size of lamp used, and the application of the lamp reflector. The lamp 6 is selected according to the size of the reflector 3. The lamp glass can be frosted, typically by very lightly sandblasting the surface of the lamp glass, to reduce filament reflections ("hot spots") in the output beam.

The lamp reflector 3 can be a parabolic or non-parabolic reflector. Typically, the reflector 3 may be a standard PAR (Parabolic Aluminised Reflector) parabolic lamp reflector as used, for example, in stage lighting. Such lamp reflectors are currently available in four sizes, these being 36, 46, 56 and 64. The numerals 36, 46, 56 and 64 represent the outer diameter at the open end of the reflector as a multiple of one-eighth of an inch. The outer diameter is shown as distance X in Figure 3. By way of example, the overall diameter of a 64 reflector is 8" (20.32cm) , that is, 64 x 1/8" (0.3175cm) = 8" (20.32cm) . The lamp reflector 3 can optionally include ventilation holes or cut-outs in the lower part 8 of the rear neck section 2 to allow for air circulation and cooling of the lamp 6. If additional ventilation is required, or in lamp reflectors in which the collar member surrounds the entire neck section (i.e. those lamp reflectors which have no exposed lower part in the rear neck section) , holes or cut-outs can be formed in the neck section of the lamp reflector with corresponding holes or cut-outs formed in the collar member. The inner reflecting surface 7 of the reflector 3 can be dimpled or faceted to remove filament reflections ("hot spots") and can further include optical coatings to reduce infra-red e missions. The dimpling or faceting of the inner reflecting surface 7 can be employed alone, or in combination with the frosting of the lamp glass as discussed hereinabove.

Suitable types of lamp for use in the known sizes of lamp reflectors are indicated in Table 1.

Table 1

36

6 volt 35 watt "Halostar" (trade name) lamps, typically an

M116 lamp supplied by Osram and GE, or a 13094 lamp supplied by Phillips;

150 watt HTI lamps supplied by Osram;

30 volt 250 watt DYG lamps; and

120, 220, 240 volt 650 watt Al/247² lamps.

46

The above-mentioned lamps suitable for the 36 reflector; and 120/240 volt 500 watt "Maxlight" lamps as available from DLD Productions Limited.

56

The above-mentioned lamps suitable for the 36 and 46 reflectors; but not including the 6 volt 35 watt "Halostar" lamps;

120/240 volt 1000 watt "Maxlight" lamps as available from

DLD Productions Limited;

MSD200 (Medium Source Daylight; 200 watt) lamps as supplied by Phillips; and

MSR200 and MSR400 (Medium Source Rare earth, 200 and 400 watt, optionally with Hot Restrike) lamps as supplied by

Phillips.

64

30 volt 250 watt DYG lamps; and

500 and 1000 watt "Maxlight" lamps as available from DLD

Productions Limited.

DYG is an ANSI lamp standard

2

Al/247 is an LIF Standard lamp number

Lamp reflectors usually comprise a normal grade aluminium body clad with a super-pure (i.e. typically 99.99% purity) aluminium layer on the inner reflecting surface. The thickness of such clad aluminium layers is usually about 15% of the overall thickness of the body of the lamp reflectors. This clad aluminium is known in the trade as "ALCLAD" . The main body of the reflector is usually made of normal grade aluminium to reduce cost since only the inner surface of the lamp reflector is required to have a high reflectivity. Lamp reflectors are fabricated by first mechanically spinning a blank into shape, then polishing, electrobrightening and sealing the inner reflecting surface. The blanks are typically about 0.05" (0.127cm) in thickness. The process of electrobrightening or electrolytic polishing is employed to remove microscopic irregularities in the reflector surface. During the process of electrobrightening the back surface of the lamp reflector hardens, increasing the rigidity of the reflector. Where a very bright finish is not required the inner reflecting surface can be bright dipped or plated and anodized.

The collar member 1 includes in its tubular wall three similarly shaped slots 9 angularly spaced 120 apart. The slots 9 defined in the collar member 1, which when mounted on the neck section 2 of the lamp reflector 3 , cooperate and engage with respective projections 10 provided on the rear neck section 2 of the lamp reflector 3. It will be understood that the present invention is not limited to such an arrangement of slots 9 and projections 10. Any number of slots and projections arranged with any angular spacing alternatively can be employed (e.g. two projections and corresponding slots located on opposed sides along the diameter of the collar member and neck section of the reflector) . It will also be noted that alternatively the slots can be defined in the neck section 2 of the reflector 3 and the cooperating projections provided on the collar member 1. The shaped slots 9 define first and second slot portions 11,12 which when the respective projections 10 are located therein fix the lamp 6 and hence lamp filaments 13 (light source) at first and second predetermined positions relative to the focal point F of the lamp reflector 3. It is by moving the lamp filaments 13 about the focal point F of the reflector 3 that the ourput beam angle and/or intensity is varied.

Figure 3 illustrates a parabolic lamp reflector 3. The focal point F of the lamp reflector 3 is located a distance L from the origin 0 of the parabolic curve of the lamp reflector 3. The focal point F of lamp reflectors varies with application, but typically for a PAR64 narrow beam reflector the focal point F is about 40mm from the origin 0.

With the projections 10 in the first and second slot portions 11,12 the collar member 1 is located in first (forward) and second (rear) fixed positions in relation to the lamp reflector 3. The lamp 6 which is mounted to the collar member 1 can thus be located accurately at two predetermined positions within the lamp reflector 3. The engagement of the projections 10 in the slot portions 11,12 ensures the lamp 6 and hence the lamp elements 13 can be located repeatedly at the same first and second positions in the lamp reflector 3. The output beam can thus be selected from one of a first and second beam angle/intensity which corresponds to the location of the projections 10 in the first or second slot portions 11,12. It will be understood that the present invention is not limited to only first and second slot portions 11,12, but that a plurality of such slot portions for locating a lamp at a plurality of fixed positions within the reflector 3 can be employed. In this embodiment the slots 9 include a portion 14 which extends to an edge of the collar member 1 so as to allow the collar member 1 to be separated from the reflector 3. This allows the lamp 6 to be changed easily. In collar members in which a portion of the slots extends to an edge, removal of the collar member from the reflector can be prevented by locating a 'jubilee' clip about the lower end of the collar member 1 below the projections 10. Alternatively, where removal of the collar member 1 is not required the slots 9 defined in the collar member 1 can be arranged so as not to include a portion 14 which extends to an edge of the collar member 1. The projections 10 on the neck 2 of the reflector 3 thus will be captively held in the respective slots 9 defined in the collar member 1.

In use, the collar member 1 is located on a reflector 3 as illustrated in Figures 1 and 2. When projections 10 are located in the first slot portions 11 (forward position) the lamp 6 is located further from the origin O of the parobolic curve of the reflector 3 than when the projections 10 are located in the second slot portions 12 (rear positions) . In order to locate the projections 10 in the first slot portions 11, the collar member 1 is pushed fully onto the neck section 2 of the reflector 3 and rotated in a clockwise direction in relation to the reflector 3. In order to to locate the projections 10 in the second slot portions 12, the collar member 1 is pushed partly onto the neck section 2 of the reflector 3 and rotated in an anti-clockwise direction in relation to the reflector 3.

Typical variations in beam angle and beam intensity which can be achieved using a PAR64 reflector are illustrated in Tables 2 and 3 hereinbelow. In the forward lamp position which corresponds to the location of projections 10 in the first slot portions 11 the light source (lamp filaments 13) is located about 3.5mm beyond the focal point F from the origin O along the optical axis, and in the rear lamp position which corresponds to the location of projections 10 in the second slot portions 12 the light source is located about 3.5mm closer to the origin O than the focal point F. The total displacement between the forward and rear positions is about 7mm and is represented by Y in the Figures. The forward and rear positions are shown as reference signs F" and F', respectively, in Figure 3l Table 2 - PAR64 Reflector with 1000W frosted Lamp

Lamp Forward Position

Center intensity 4000 foot-candle (43055.6 lux)

50% Diameter 16 inches (40.64cm) Beam Angle 9 degrees

10% Diameter 38 inches (96.52cm) Field Angle 18 degrees

Lamp Rear Position

Center intensity 2000 foot-candle (21527.8 lux)

50% Diameter 24 inches (60.96cm) Beam Angle 12 degrees

10% Diameter 48 inches (121.92cm) Field Angle 24 degrees

Table 3 - PAR64 Reflector with 500W Lamp

Lamp Forward Position

Center intensity 4000 foot-candle (43055.6 lux)

50% Diameter 12 inches (30.48cm) Beam Angle 6 degrees

10% Diameter 18 inches (45.72cm) Field Angle 12 degrees

The center intensity values given in Tables 1 to 3 are those illuminances measured at a distance of 10 feet (304.8cm) along the optical axis from the origin O.

The 50% intensity values given in Tables 1 to 3 are those diameters about the optical axis at 10 feet (304.8cm) from the origin O where the illuminance has fallen to half that value of the center intensity (i.e. 2000 foot-candle (28527.8 lux) and 1000 foot-candle (10763.9 lux) for center intensities of 4000 foot-candle (43055.6 lux) and 2000 foot-candle (2152^*7.8 lux) , respectively) . The 10% intensity values given in Tables 1 to 3 are those diameters about the optical axis at 10 feet (304.8cm) from the origin where the illuminance has fallen to one tenth of that value of the center intensity (i.e. 400 foot-candle (4305.56 lux) and 200 foot-candle (2152.78 lux) for center intensities of 4000 foot-candle (43055.6 lux) and 2000 foot-candle (21527.8 lux), respectively) .

Figures 4 to 9 illustrate collar members 1 for use with the fitting in accordance with the first embodiment of the present invention. In each of the collar members 1, the slots 9 include only first and second slot portions 11,12. However, it will be understood that further slot portions can be included if required.

A first alternative collar member 1 is illustrated in Figure 4. The collar member 1 is located in a first position by pushing the collar member 1 onto the neck section 2 of the reflector 3 and rotating the collar member 1 in a clockwise direction in relation to the reflector 3 to engage a projection 10 in a first slot portion 11. The collar member 1 is located in a second position by pushing the collar member 1 onto the neck section 2 of the reflector 3 and rotating the collar member 1 in an anti-clockwise direction in relation to the reflector 3 to engage a projection 10 in a second slot portion 12. By locating the projections 10 in either of the first or second slot portions 11,12, respective predetermined first and second positions of a lamp (mounted to the collar member 1) in the reflector 3 are achieved.

A second alternative collar member 1 is illustrated in Figure 5. The collar member 1 is located in a second (rear) position by pushing the collar member 1 onto the neck section 2 of the reflector 3 and rotating the collar member 1 in an anti-clockwise direction in relation to the reflector 3 to engage a projection 10 in a second slot portion 12. The collar member 1 is located in a first (forward) position by pushing the collar member 1 further onto the reflector 3 and rotating the collar member 1 in an anti-clockwise direction in relation to the reflector 3 to engage a projection 10 in a first slot portion 11. The first and second slot portions 11,12 in this case both extend in a direction transverse to the axis of the reflector 3 and are offset from each other along the axis.

A third alternative collar member 1 is illustrated in Figure 6. The collar member 1 is located in a first position by pushing the collar member 1 fully onto the neck section 2 of the reflector 3, rotating the collar member 1 in an anti-clockwise direction in relation to the reflector 3 and pushing the collar member 1 further onto the neck section 2 of the reflector 3 to engage a projection 10 in a first slot portion 11. The collar member 1 is located in a second position by pushing the collar member 1 onto the neck section 2 of the reflector 3 , rotating the collar member 1 in a clockwise direction in relation to the reflector 3 and pulling the collar member 1 away from the neck section 2 of the reflector 3 to engage a projection 10 in a second slot portion 12.

A fourth alternative collar member 1 is illustrated in Figures 7 to 9. The collar member 1 has a partially closed end which is adapted to fit over the rear neck section 2 of a lamp reflector 3. A lamp reflector 3 which is adapted to receive the collar member 1 is illustrated in Figures 10 to 12. The collar member 1 is fabricated from sheet material (typically 18 guage, 0.11cm) and is finished with a black anodize. The inner surface of the collar member 1 is preferably coated, e.g. by spraying, with TEFLON (a Registered Trade Mark) . The TEFLON coating allows the collar member 1 to be moved more readily about the neck of a reflector 3, particularly when hot from use. The partially closed end of the collar member 1 includes a first cut-out 15 in which a lamp holder is located. A lamp holder is mounted to the collar member 1 by screws located through holes 16 defined in the partially closed end of the collar member 1. The collar member 1 has two slots 9 defined on opposed sides along the diameter of the tubular wall thereof. The slots 9 cooperate with projections 10 located on the neck section 2 of the reflector 3. The slots 9 do not extend to an edge of the collar member 1 and thus when the collar member 1 is located on the neck 2 of the reflector 3 the projections 10 are captively held within the slots 9 preventing removal of the collar member 1 from the reflector 3. The width of the slots 9 is selected to suit the dimensions of the projections 10. Typically, the width of the slots 9 and the diameter of the projections 10 is about 0.25" (0.635cm) . The projections 10 typically comprise a threaded guide pin or stud which is screwed into a pilot hole formed in the neck section 2 of the lamp reflector 3. The slots 9 include first and second slot portions 11,12 which, when the respective projections 10 on the reflector 3 are located therein, define first and second axial positions of the collar member 1 in relation to the lamp reflector 3. The displacement Y between the first and second positions (forward and rear positions) is typically 0.1875" (0.476cm) for 500 watt lamps and 0.25" (0.635cm) for 1000 watt lamps. A lamp mounted to the collar member 1 is located in a first (forward) position by pushing the collar member 1 towards the body of the relfector 3 , that is by locating the projections 10 in slot portions 11. A lamp mounted to the collar member 1 is located in a second rear (position) by pulling the collar member 1 away from the body of the reflector 3, that is, by locating the projections 10 in the slot portions 12.

Referring to Figure 8, the tubular wall of the collar member 1 also includes two cut-outs 17. These cut-outs 17 are broadly co-extensive with cut-outs 18 defined in the neck section 2 of the lamp reflector 3 and provide an opening to the interior of the neck section 2 of the lamp reflector 3 which allows for air circulation and cooling. The cut-outs 18 defined in the neck section 2 of the reflector 3 can be larger in size than those defined in the tubular wall of the collar member 1. Preferably, the corners of the cut-outs 17,18 defined in the collar member 1 and the neck section 2 of the reflector 3 are rounded.

In order to ensure that the collar member 1 is located, in use, in one of the first and second positions, shaped spacers 19 are located between the outer surface of the neck section 2 of the reflector 3 and the inner surface of the collar member 1. Each spacer 19 has a hole 20 defined therein and is located over a respective projection 10 on the neck section 2 of the reflector 3. The spacers 19 are fabricated from shim steel having a thickness of 0.01-0.015" (0.0254-0.0381cm) and are shaped to have a curve in at least one direction of typically 1.25 rad. Preferably, the edges of the spacers 19 are de-burred and the outer convex surfaces are coated with TEFLON.

A fitting in accordance with a further embodiment of the present invention is illustrated in Figure 15. In this embodiment a U-shaped assembly frame 21 is mounted to the neck section 2 of the lamp reflector 3 which can be a parabolic or non-parabolic reflector. The extending arms 22 of the U-shaped assembly frame 21 are fixed by screws 23 to the projections 10 on the neck section 2 of the lamp reflector 3. The assembly frame 21 is coupled to the neck section 2 of the lamp reflector 3 in such a manner as to define a channel between the extending :---s 22 thereof and the neck section 2. Figures 17 arα 18 respectively illustrate elevational views of the assembly frame 21 from one side and from below. The extending arms 22 include projections 24 at their distal ends. These projections 24, in use, rest against the rear surface of the lamp reflector 3 and are provided to locate the assembly frame 21 accurately in relation to the neck section 2 of the lamp reflector 3.

A collar member 1, to which a lamp holder 5 is fixed, is axially slidably mounted over the neck section 2 of the lamp reflector 3 in that channel defined between the neck section 2 and the assembly frame 21. The axial position of the collar member 1 in relation to the lamp reflector 3 is controlled by an adjustment means 25. The adjustment means 25 comprises an adjuster plate 26, an adjuster 27 and a knob 28. The adjuster plate 26 is fixed to the partially closed end of the collar member 1 and includes a threaded extending part 28 which cooperates and engages with a corresponding threaded part of the adjuster 27. The adjuster 27 extends through an opening 30 formed in an end 31 of the assembly frame 21. The opening 30 has a bush 32, preferably of TEFLON, located therein. Movement of the collar member 1 in the axial direction of the neck section 2 of the lamp reflector 3 is achieved by rotating the knob 28 in a clockwise/anticlockwise direction. The adjuster 27 may include a locking device, e.g. a locking nut, which engages with the end 31 of the assembly frame 21 so as to fix the axial position of the collar member 1. The use of a locking device prevents movement of the collar member 1 on the neck section 2 of the reflector 3 ring transport. The collar member 1 is illustrated in F-- αres 19 to 21. The collar member 1 has an elongate opening 15 defined in its partially closed end in which the lamp holder 5 is located. The axial position of the collar member 1 to which the lamp holder 5 is mounted determines the angle and intensity of the output beam. The lamp holder 5 and adjuster plate 25 are mounted to the collar member 1 by machine screws 33. In this respect, this collar member 1 is of broadly similar construction to that collar member 1 illustrated in Figures 7 to 9. The collar member 1 has two slot portions 9 defined in the tubular wall portion thereof. The slot portions 9 are defined in opposed sides along the diameter of the tubular wall of the collar member 1. In the assembled configuration, the slot portions 9 are located over the projections 10 on the neck section 2 of the lamp reflector 3. The slot portions 9 in the illustrated collar member 1 extend to a free end of the tubular wall, allowing the collar member 1 to be removed from the neck section 2 of the lamp reflector 3. However, it will be understood that a collar member 1 such as illustrated in Figures 7 to 9 which has captive slot portions 9 defined therein could also be employed. The tubular wall portion of the collar member 1 has two further cut-outs 17 defined therein. Those cut-outs 17 correspond with cut-outs 18 defined in the neck section 2 of the lamp reflector 3 and provide an open passage for air-circulation.

In this embodiment, a lamp can be located accurately in any position along the optical axis of the reflector within the limits of the axial movement of the collar member 1. The limits of movement of the collar member 1 are either determined by the configuration of the adjustment means 25, or by the axial dimensions of the slot portions 9 defined in the tubular wall of the collar member 1.

Efficiency measurements for non-parabolic reflectors which can be used in _ combination with the lamp fittings of the present invention are as follows.

Table 4 - PAR 64 Reflector with 1000 watt 120 volt "Maxlight" lamp.

Beam Angle 7.6 degrees. Field Angle 13 degrees.

Intensity measurements (foot-candle)

x-coordinate (feet)

-3 -2 -1 0 1

0 540 0 536 523

-3 - 415 475 431

Total . Intensity 32024 foot-candle

Beam Lumens 8655

Lamp Lumens 26000

Efficiency 33%

Luminous Intensity 668000 Candela Average Intensity at 1/3 spot diam. 1331 foot-candle Average Intensity at 2/3 spot diam. 931 foot-candle Average Intensity at edge 510 foot-candle Table PAR 56 Reflector with 1000 watt 120 volt

"Maxlight" lamp.

Beam Angle 8.5 degrees Field Angle 13 degrees,

Intensity Measurements (foot-candle) x-coordinate

(feet)

-3 -2 -1 0 1 2 3

0 4

1

-2 - 572 696 722 629 448 -

-3 - - 405 410 357 - -

Total Inrensiittyy 25211 foot- -candle

Beam Lumens 6814

Lamp Lumens 26000

Efficiency 26%

Luminous Intensity 460000 Candela

Average Intensity at 1/3 spot diam. 1007 foot-candle

Average Intensity at 2/3 spot diam. 726 foot-candle

Average Intensity at edge 441 foot-candle

Table 6 - PAR 64 Reflector with 500 watt 120 volt "_idrn _oM_, axlight" lamp. _ft)ee

Beam Angle 6 degrees. Field Angle 10 degrees.

Intensity Measurements (foot-candle) x-coordinate

(feet)

-3 -2 -1 0 1 2 3

3 - - 148 175 143 - -

CD -P - 5 245 - tύ 2 258 460 514 45

1 204 502 874 1000 879 505 193 0 243 748 1190 1300 1190 701 249 o — υ -1 221 604 988 1150 942 564 203

1

>1 -2 - 285 452 532 422 243 -

-3 — - 137 155 130 - —

Total . Intensity 19202 foot- -candle

Beam Lumens 5190

Lamp Lumens 13000

Efficiency 40%

Luminous Intensity 520000 Candela

Average Intensity at 1/3 spot diam. 1027 foot-candle

Average Intensity at 2/3 spot diam. 538 foot-candle

Average Intensity at edge 183 foot-candle

Table PAR 56 Reflector with 500 watt 120 volt _i "_d r_naMaxlight" lamp. _{)t ee}

Beam Angle 6.2 degrees. Field Angle 10 degrees.

Intensity Measurements (foot-candle) x-coordinate

(feet)

-3 -2 -1 0 1 2 3

3 - 125 142 130 - - α.

4-1 2 236 385 456 430 259 -

1 186 459 762 867 810 537 200 0 235 590 926 980 871 605 235

O <—1 o -— -1 175 426 634 706 617 390 176

1

>1 -2 192 323 366 322 206 -

-3 - 113 112 112 - -

Total . Intensity 16310 foot- -candle

Beam Lumens 4408

Lamp Lumens 13000

Efficiency 345

Luminous Intensity 392000 Candela

Average Intensity at 1/3 spot diam. 774 foot-candle

Average Intensity at 2/3 spot diam. 441 foot-candle

Average Intensity at edge 246 foot-candle

Table 8 - PAR 36 Reflector with 35 watt 6 volt "Halostar¹ lamp.

Beam Angle 3.3 degrees. Field Angle 7.1 degrees.

Intensity Measurements (foot-candle) x-coordinate

(feet)

-3 -2 -1 0 1

7 8 8

CD

4-1 22

US 9 16 20 16

C

•H AS 6 17 39 67 49 27 12

TI CD

<D o 7 23 53 92 67 30 11 o υ -1 6 19 43 67 50 18 10

1 -2 9 17 23 16 9 -3 5 5 5

Total Intensity 908 foot-candle Beam Lumens 245

Lamp Lumens 910

Efficiency 27%

Luminous Intensity 36800 Candela Average Intensity at 1/3 spot diam. 54 foot-candle Average Intensity at 2/3 spot diam. 20.7 foot-candle Average Intensity at edge 7.5 foot-candle

Table 9 - PAR 56 Reflector with MSD200 lamp.

Beam Angle 3 degrees. Field Angle 6 degrees.

Intensity Measurements (foot-candle) x-coordinate

(feet)

-3 -2 -1 0 1 2 3

3 - - 97 105 81 - -

2 - 109 255 390 245 100 -

1 75 399 1170 2090 865 210 70 0 85 520 1660 3500 1750 350 85

-1 75 300 1220 1920 1200 275 75

-2 - 120 467 770 420 123 -

-3 - - 98 137 136 - -

Total . Intensity 21547 foot- -candle

Beam Lumens 5824

Lamp Lumens 12500

Efficiency 47%

Luminous Intensity 1400000 Candela

Average Intensity at 1/3 spot diam. 1484 foot-candle

Average Intensity at 2/3 spot diam. 383 foot-candle

Average Intensity at edge 93 foot-candle

Table 10 - PAR 36 Reflector with 150 watt 115 volt HTI lamp

Beam Angle 7.6 degrees. Field Angle 15 degrees.

Intensity Measurements (foot-candle) x- coordinate

(feet)

-3 -2 -1 0 1 2 3

3 - - 188 197 167 - -

0) ->

4-1 ^Δ - 222 287 314 286 213 -

C - 1 232 374 432 428 388 300 181 "H AS Q) ^U 227 402 520 540 494 392 224

O 4-1

0 ^-1 173 273 392 471 451 370 235

U -2 - 145 190 230 220 195 -

-3 - - 90 111 113 - -

Total Intensity 10675 foot- -candle

Beam Lumens 2885

Lamp Lumens 10000

Efficiency 29%

Luminous Intensity 216000 Candela

Average Intensity at 1/3 spot diam. 447 foot-candle

Average Intensity at 2/3 spot diam. 303 foot-candle

Average Intensity at edge 179 foot-candle

In the measurements given in Tables 4 to 10 the lamps are operated at full intensity and measurements obtained at a distance of 20 feet from the lamp. The results in Tables 4 to 7 are obtained with the "Maxilight" lamps operating at 115 volts. The Beam Angle is that angle measured at 20 feet from the lamp where the illuminance has fallen to 50% of that measured along the optical axis.

The Field Angle is that angle measured at 20 feet from the lamp where the illuminance has fallen to 10% of that measured along the optical axis.

The Intensity measurements are those values measured at a distance of 20 feet from the lamp at points on a grid having 1 foot intervals on and about the optical axis (coordinate 0,0) .

The Total Intensity is the sum of the measured intensity values, in this case 37 in total.

The Beam Lumens is the Total Intensity divided by the number of measured values (37) and multiplied by half the distance of the measurement (i.e. 20 feet/2 = 10 feet).

The Lamp Lumens is the total light output from the lamp.

The Efficiency is the Beam Lumens divided by Lamp Lumens.

The Candela is the measured intensity value at a distance of 20 feet from the lamp along the optical axis multiplied by the square of the distance from the lamp.

The Average Intensity at 1/3 Spot Diam. is the average of those intensity values measured at coordinates (0,1) , (1,1) , (1,0) , (1,-1) , (0,-1), (-1,-1) , (-1,0) and (-1,1).

The Average Intensity at 2/3 Spot Diam. is the average of those intensity values measured at coordinates (0,2), (1,2) , (2,2) , (2,1) , (2,0) , (2,-1) , (2,-2) , (1-2) , (0,-2) , (-1,-2) , (-2,-2) , (-2,-1) , (-2,0) , (-2,1) , (-2,2) and (-1,2) .

The Average Intensity at edge is the average of those intensity values measured at coordinates (0,3) , (1,3) , (3,1) , (3,0) , (3,-1) , (1,-3) , (0,-3) , (-1,-3) , (-3,-1) , (-3,0) , (-3,1) and (-1,3) .

The above-described lamp fittings of the present invention when used in combination with non-parabolic reflectors can find application in T.V. , film and stadium lighting, in infra-red lighting, and in search and flood lighting. These applications will be described hereinbelow.

Conventional film and T.V. lighting suffers from the disadvantage that a number of high power lamps are required to obtain sufficient coverage of the film or T.V. set. These lamps are typically 2.5, 4, 6, 12, 16 or 18 kilo-watt lamps which are bath very expensive and have only a short lamp life (usually less than 300 hours) . The present invention by providing an array of non-parabolic reflectors including MSD200, MSR200, MSD400 or MSR400 lamps achieves very high light outputs. By way of example, the output from a single MSD200 watt unit using a 7" (PAR 56) "Maxlight" reflector (manufactured by DLD Productions Ltd) has been measured at 1.4 million candela.

A film lighting array 100 of the present invention is shown in Figure 22. The array 100 comprises six lamp units 102 which are arranged in two parallel banks of three lamp units 102. The lamp units 102 each comprise a 7" "Maxlight" reflector 104, a long-life compact arc metal halide lamp 106 and a variable focus lamp fitting 108. The variable focus lamp fitting 108 can be any of the above-described lamp fittings, and provides a means for varying the beam width. Each bank of three lamp units 102 is mounted on a movable bar 110 which allows the banks to be spaced apart to obtain the desired overall beam spread.

The reflector 104 and lamp 106 of each lamp unit 102 is provided in a tube section 112. The front part 114 of the tube section 112, that part which extends downstream of the reflector 104, prevents any or most of the spill light from coming off the reflector 104. The front ost part 116 of the reflector 104, which is open, is provided with means, usually clips, for receiving any required diffusion material. Each lamp unit 102 also includes downstream of the reflector 104 an ultra-voilet/colour correction filter 118 and a lens 120 for providing increased beam spread. The filter 118 is employed to prevent the transmission of ultra-voilet radiation having wavelengths below 400nm. The transmission of the filter 118 can be further enhanced by using an anti-reflective coating. The filter 118 is usually formed from a single sheet of rolled PYREX (a Registered Trade Mark) glass which further acts as a shield in the case of explosive lamp failure.

The array of lamp units 102 is mounted within a housing 122 which is adjustably mounted to a support frame 124. The housing 122 and support frame 124 together with the variable focus lamp fitting 108 can be motorized to allow for remote operation.

The lighting array 100 of the present invention provides a significantly higher light output as compared to that achieved using conventional lamps. The array of the present invention also has much lower running costs. By way of example, using an array of six 200 or 400 watt lamps the total power consumption is 1.2 or 2.4kw which compares to a 6kw HMI film lamp which is conventionally used. Moreover, the lifetime of the lamps used in the present invention is far greater than that obtained from a conventional HMI lamp. A HMI lamp has a typical lifetime of only 300 hours as compared to 2000 hours for a long-life MSD lamp. In addition to savings achieved in the cost of running the lighting array of the present invention, the purchase cost of the lamps used in the present invention is significantly lower.

The lighting array of the present invention also has the advantage that it is of compact size and is lightweight, thus offering significant advantages when filming in remote locations. The reduced power consumption of the lighting array of the present invention is also advantageous when filming on location since fewer or smaller generator trucks will be required.

The application of the present invention in infra-red lighting, for example in search and flood lights, will now be described.

Known infra-red search lights comprise fixed focus systems ..which include two infra-red lamps, one fixed flood lamp and one fixed spot lamp. By using the lamp fittings of the present invention, however, a single lamp variable focus unit can be provided. In order to provide an efficient infra-red reflector surface the reflector, a non-parabolic reflector, is coated with pure gold. In order to increase the infra-red performance of the lamp and provide an increased lamp lifetime the lamp can be operated at a voltage below its rated voltage, e.g. a 120 volt 500 watt "Maxlight" lamp can be operated at 80 volts. It has been determined that the 500 watt "Maxlight" lamp can be operated down to 16 lumens/watt without affecting performance. These modifications provide lamps of a greater working range and allow the use of cameras of lower resolution. Such an arrangement can be used with a 4.5" non-parabolic reflector in hand-held 6, 12 or 24 volt torches employing proprietary lamps for surveillance operations. The above-described infra-red search lights can also be provided in a waterproof housing for external use.

The present invention can also be employed to provide variable focus search and flood-lighting, for example of the exterior of buildings. In such applications, dichroic filters can be used to provide coloured light.

In addition, any of the T.V. , film, stadium, infra-red, search and flood lighting arrangements described above can be powered directly from d.c. supplies, thereby allowing the units to be portable.

It will be understood by a person skilled in the art that various modifications and adaptations can be made to the embodiments described hereinabove without departing from the scope of the present invention as defined in the claims.

Claims

CLAIMS ;

1. A lamp fitting including a collar member which can be fitted in, or over, a neck section of a reflector and to which a lamp can be mounted, said collar member including a fitting for cooperating with the neck section of the reflector so as to allow variation in axial position of the reflector in relation to the collar member.

2. A lamp fitting as defined in claim 1, further including a reflector having a neck section which is fitted coaxially to the collar member.

3. A lamp fitting as defined in claim 2, wherein said fitting forms part of a slot and follower assembly in which at least one follower rides in a respective slot, so that the relative positior of the collar member and the neck section of the reflect- r is governed by the position of the at least one follower in the at least one slot.

4. A lamp fitting as defined in claim 3, wherein the at least one slot is defined in a sidewall of the collar member.

5. A lamp fitting as defined in claim 4, wherein the at least one slot is an open ended slot which extends to an edge of the sidewall.

6. A lamp fitting as defined in claim 4, wherein the at least one slot is a closed slot defined within the sidewall.

7. A lamp fitting as defined in any one of claims 2 to 6, wherein said collar member is located over the neck section of the reflector.

8. A lamp fitting as defined in claim 7, wherein each follower is a projection on an outer circumferential surface of the neck section of the reflector.

9. A lamp fitting as defined in any one of claims 2 to 8, further including a frame assembly having extending arms which are mounted in spaced relation about the neck section and collar member.

10. A lamp fitting as defined in claim 9, wherein said frame assembly is U-shaped.

11. A lamp fitting as defined in claim 9 or claim 10, when appendant upon claim 8, wherein the extending arms of the frame assembly are fixed to projections on the neck section of the reflector.

12. A lamp fitting as defined in any one of claims 9 to 11, wherein said collar member is in axial slidable fit in a space defined between an outer circumferential surface of the neck section of the reflector and an inner circumferential surface of the extending arms of the frame assembly.

13. A lamp fitting as defined in any one of claims 9 to 12, further including an adjustment means, said adjustment means including a threaded adjuster which is coupled to the web of the frame assembly and to the collar member, whereby rotation of the threaded adjuster effects axial movement of the collar member in relation to the neck section of the reflector and the frame assembly.

14. A lamp fitting as defined in claim 13, wherein said threaded adjuster comprises a threaded bolt part which is fixed to the collar member and a threaded nut part which is rotatably mounted to the web of the frame assembly, whereby rotation of the threaded adjuster effects axial movement of the collar member in relation to the reflector and the frame assembly.

15. A lamp fitting as defined in any one of claims 9 to 14, wherein the distal end of each of the arms of the frame assembly has two extensions extending therefrom which are adapted to engage on the rear surface of the reflector.

16. A lamp fitting as defined in claim 15, wherein each of said extensions are located at the longitudinal edges of said arms.

17. A lamp fitting as defined in any one of claims 2 to 16, wherein each slot includes first and second slot portions, which when the respective follower is selectively located therein, fix the collar member in a selected one of first and second axial positions relative to the neck section of the reflector.

18. A lamp fitting as defined in claim 17 when appendant upon claim 4, wherein the first and second slot portions are defined in positions spaced about a circumference of the sidewall.

19. A lamp fitting as defined in any one of claims 2 to 18, further comprising spacers which are located between an outer circumferential surface of the neck section of the reflector and an inner circumferential su ".ace of the collar member.

20. A lamp fitting as defined in claim 19, wherein said spacers each have a hole defined therein through which a respective one of the at least one follower is located, and are shaped to have a curve in at least one direction.

21. A lamp fitting as defined in any one of claims 1 to 20, wherein the collar member includes a transverse end wall to which a lamp can be mounted.

22. A lamp fitting as defined in claim 21, wherein said transverse end wall has an opening defined therein in which a lamp can be located.

23. A lamp fitting as defined in any one of claims 1 to 22, wherein said collar member has at least one ventilation cut-out defined therein.

24. A lamp fitting as defined in any one of claims 2 to 23, wherein said reflector is a parabolic reflector.

25. A lamp fitting as defined in any one of claims 2 to 23, wherein said reflector is a non-parabolic reflector.

26. A lamp fitting as defined in any one of claims 2 to 25, wherein said lamp reflector has a facetted surface.

27. A lamp fitting as defined in any one of claims 1 to 26 in combination with a lamp.

28. A lamp fitting as defined in claim 27, wherein said lamp comprises a bulb and bulb holder.

29. A lamp fitting, comprising: a frame assembly having extending arms; a reflector which includes a neck section having projections on opposed sides thereof, the neck section being located between the extending arms and fixedly mounted to the extending arms by said projections; a collar member which is located between the extending arms of the frame assembly and the neck section of the reflector, the collar member having slots defined in opposed sides thereof in which respective projections are movably located, thereby allowing axial displacement of the collar member in relation to the reflector and frame assembly; and a lamp holder which is mounted to the collar member.

30. A lamp fitting as defined in claim 29, further comprising an adjustment means, said adjustment means comprising a threaded adjuster which is coupled to the web of the frame assembly and to the collar member, whereby rotation of the threaded adjuster effects axial movement of the collar member in relation to the reflector and the frame assembly.

31. A lamp fitting as defined in claim 30, wherein the threaded adjuster comprises a threaded bolt part which is fixedly mounted to the collar member and a threaded nut part which is rotatably coupled to the web of the frame assembly, whereby rotation of the threaded nut part effects axial movement of the collar member in relation to the neck section of the reflector and the frame assembly and thereby provides a means for positioning a lamp mounted in the lamp holder along the optical axis of the reflector.

32. A fitting as defined in claim 31, wherein the threaded nut part has a knob fixed thereto.

33. A lamp unit comprising a non-parabolic reflector and a variable focus lamp fitting.

34. A lamp unit as defined in claim 33, further comprising a tubular section located about the reflector.

35. A lamp unit as defined in claim 33 or 34, further comprising downstream of the reflector a filter for ultra-voilet and colour correction.

36. A lamp unit as defined in any one of claims 33 to 35, further comprising downstream of the reflector a lens for diverging a reflected beam.

37. A lighting assembly comprising an array of lamp units as defined in any one of claims 33 to 36.

38. A lighting assembly as defined in claim 37, wherein said lamp units are provided within a housing.

39. A lighting assembly as defined in claims 37 or 38, wherein said housing is attached to a supporting frame which allows for the directional positioning of the lamp units.

40. A lighting assembly as defined in any one of claims 37 to 39, wherein said lamp units are mounted on movable bars, thereby providing means for varying the beam spread.

41. A lighting assembly as defined in any one of claims 37 to 40, wherein said movable bars are arranged parallel to one another.

42. A lighting assembly as defined in any one of claims 39 to 41, wherein the housing, the supporting frame and the variable focus lamp fitting of each lamp unit are motorised.

43. A lamp unit as defined in claim 33, wherein said reflector surface is coated with a layer of gold.

44. A lamp fitting substantially as hereinbefore described with reference to any of Figures 1 to 14 or Figures 15 to 21 of the accompanying drawings, optionally in combination with a reflector or a lamp.

45. A lighting assembly substantially as hereinbefore described with reference to Figures 22 or 23 of the accompanying drawings.