LIGHTING UNIT

Abstract: The lighting unit (10) is designed for use with video cameras. The lighting unit is light in weight, compact in size and portable. There is a housing (11) including a reflector (30) and a light source (33). A focussing lense (12) is moveably mounted on the housing (11) forwardly of the light source (33). The light source is moveable between two final positions to provide either floodlight or spotlight. This enables the photo amateur to obtain illumination as a professional at affordable costs.

Description: Ligthing Unit The present invention relates to improvements in lighti units and in particular to lighting units of the type us with video cameras. Lighting units for use with video recorders are known, ho ever, such prior art lighting units have a number of problems First, in the known type of lighting units the light source i movable relative to a focussing lens to provide a light bea of either spotlight or floodlight quality. This constructio of light has the disadvantage that it requires a two or thre lens system to provide the necessary floodlight/spotlight cha racteristic light beams. In addition, this known light unit i complicated in construction. A further disadvantage of the prior art lighting units is tha they generally use either a parabolic or an elliptical type o reflector. The parabolic type reflector has the disadvantag that the light beam cannot be fully controlled by the len system and hot spots in the central area of the light bea often require a diffuser to evenly distribute the light beam The elliptical type reflector has the disadvantage that direc light emission from the filament of the bulb is reduced an inefficient because the bulb is positioned horizontally an with the glass tip facing forwardly thus interfering wit direct light flow from the filament. Further, because of th proximity of the lamp filament to the rear of the reflector and since the light bulb must be inserted through an apertur in the rear of the reflector, this results in considerabl loss of reflective area and thus efficiency. Accordingly, it is an object of the present invention to pro vide a lighting unit which is portable and which also may b easily attached to a video camera. This requires a lightin unit which is light in weight and compact in size. As a matte of fact, the lighting unit should provide floodlight and spot light with high efficiency and high optical qualities. According to the invention, the solution to this objective i provided by a lighting unit comprising a housing including reflector mounted within the housing, a removable light sourc fixed within the housing and disposed within the region of th reflector, and a focussing lens movably mounted on the housin forwardly of the light source, the lens at least movable bet ween positions to provide floodlight and spotlight ligh beams. In a preferred embodiment according to the invention the reflector includes a part-spherical member and is dispose slightly rearwardly of the light source. A major advantage o the invention is that it provides an extremely compact light ing unit with good beam control and good efficiency due to th reflector having a part-spherical component. The compactnes of such a lighting unit is a major advance with potential wid usage. The lighting unit is portable, compact and readily at tachable to a video camera. Further adventageous embodiments of the invention form th subject matter of several subclaims. An embodiment of the invention will now be described by way example with reference to the accompanying drawings in which: Figure 1 is a front perspective view of a lighting un according to the invention. Figure 2 is a rear perspective view of the lighti unit of Figure 1, Figures 3 and 4 are front and rear perspective views the lighting unit of Figure 1 with the focussing lens in i forward position. Figure 5 is a diagrammatic sectional view of the r flector, light source and focussing lens. Figure 6 is a perspective view of the light source ho der, Figure 7 is a cross-sectional view taken along the li VII-VII in Figure 2 of the sub-housing holding the focussi lens. Figure 8 is a rear end view, partially in cross-sec tion, of the sub-housing as shown in Figure 7, Figure 9 is a diagrammatic view of the locking mean for the sub-housing, and Figures 10 and 11 are front and underneath perspectiv views of the fan unit. Referring now to the drawings wherein similar numerals hav been used to indicate like parts, there is shown therein lighting unit generally indicated at 10 according to the in vention. The lighting unit 10 comprises a housing 11 having focussing lens 12 fixed in a sub-housing 13 which is movabl forwardly and rearwardly between retracted and extended posi tions relative to the housing 11 as shown in Figures 1 to 4 The sub-housing 13 includes resilient arms 14 similar to lea springs which slide in lateral recesses within the housing 1 and are fully contained therein in the retracted position Further details shown in Figures 1 to 4 will be illustrated i a later part of this specification. In Figure 5 there is illustrated the construction of reflecto 30 located within the housing 11. The reflector 30 comprises part-spherical mumber 31 being disposed slightly rearwardly o the light bulb 33 forming the light source. The spherical mem ber 31 comprises a light reflecting mirror-like material. I is urged forwardly by a compression spring 32 clamped betwee the rear end of the reflector 30 and the part-spherical membe 31. The forward end of said part-spherical member 31 engage several lugs 35 projecting from a tube shaped member 36. Thi mode of mounting the part-spherical member 31 provides fo centering same relative to the light bulb 33. This ensure that the reflected light from the part-spherical member 31 i emitted from a focus point which is in line or identical wit the position of the bulb filament and thus the direct ligh from the part-spherical member 31 appears to emanate from single coincident focus point. This arrangement is necessar to achieve beam control with a lens system. The tube shaped member 36 in front of the reflector 30 an surrounding the light bulb 33 prevents scattering of ligh emanating therefrom. Thus, the combination of the part-spheri cal member 31 and the tube shaped member 36 provides the dua function of achieving a focussed light beam from the part spherical member 31 and enables the capturing of more ligh than would be obtained purely by a spherical reflector fro the light bulb 33, and maintaining a focussed beam. The foca length of the lens 12 is preferably in the range 85 mm 90 mm-and more preferably 86 mm. Further, the tube shaped me ber 36 ' has an aperture 34 on its lowermost side to enable t bulb 33 to be inserted into position from the underside of t housing 11. As shown in Figure 6 the light bulb 33 is mounted on a hold 40 which is inserted into the housing 11 through a furth aperture (not shown) in the housing 11 just below the apertu 34. This aperture in the housing 11 so corresponds with t aperture 34. The holder 40 and housing 11 have correspondin engaging means for locking the holder 40 in operative posi tion. The holder 40 includes a pair of inherently resilien plastic arms 41 each of which carries a locking flange 4 which when the holder 40 is in place locates above a corres ponding flange (not shown) in the housing 11. As shown, th flange 42 slopes downwardly and outwardly to enable the read insertion of the holder 40 into the housing 11. As the holde is inserted the flanges 42 slide over the flanges (not shown in the housing 11 causing the arms 41 to be pressed inward against the inherent resilience of the arms 41. When th flanges 42 pass above the flanges in the housing 11, the arm 41 are again forced outwards to engage the flanges 42 abov the flanges in the housing 11 to lock the holder 40 in place The holder 40 further includes a pair of guide ribs 45 whic locate in corresponding recesses (not shown) within the hous ing 11 to correctly locate the holder 40. Each of the arms 4 terminates at the lower end in a finger grip 46 which as show in Figures 1 and 2 projects below the housing 11 when th holder 40 is in place. To remove the holder 40, for exampl when it is necessary to replace the bulb 33, it is a simpl matter to press the finger grips 46 towards each other to re lease the flanges 42 from the housing 11 and the holder ca then be readily removed. This mounting of the light bulb pro vides for a vertical position of same in front of the reflec tor 30. The glass accumulation at the top of the bulb 33 i always exterior to the light beam. The holder 40 further includes a pair of spaced apart electri cal contacts 47 which engage with corresponding electrica contacts (not shown) in the housing 11 to supply power to th bulb 33. The contacts 47 are preferably formed as leaf spring which are inherently urged upwards slightly. When the holde 40 is in place in the housing 11, the contacts 47 are pushe downwards slightly and form a secure electrical connecti with the contacts in the housing. Figures 7 and 8 show the sub-housing 13 holding the lens 1 being slidably mounted in the housing 11. Resilient arms 1 acting such as a leaf spring are connected to the sub-housi 13 and have finger grips 25 fastened to their free ends. I ward movement of the finger grips 25 as indicated by the a rows as shown on top of Figure 7 and the right hand side o Figure 8 provides for disengagement of teeth 22 and 24. The the sub-housing 13 is free to be moved inwardly and outwardl to provide floodlight or spotlight. Figure 7 also shows t mounting of the fan unit 50 on the housing 11 by engagement the protrusion 54 in the recesses 63. As shown in Figure 9, there is a locking means for the housi 11 generally indicated at 15 to enable the sub-housing 13. a the focussing lens 12 to be releasably locked in one or mo selected positions relative to the housing 11. More specifi ally, Figure 9 shows the situation at the bottom side Figure 7 or the left hand side of Figure 8. As sho diagrammatically in Figttre 9, the resilient arm 14 terminat in a generally H shaped member 16, with upper and lower wa portions 17, 18 respectively of the housing 11 engaging in t upper and lower recesses 19, 20 of the H shaped member. T inside surface 21 of the upper wall portion 17 has a series teeth 22 formed therein and the adjacent surface of the inn and uppermost arm 23 of the H shaped member has a series corresponding teeth 24 formed therein. The resilient arm acts to force the H shaped member outwards so that the tee 24 engage with the teeth 22 of the upper wall portion 17, that the housing 11 and sub-housing.13 are fixed relative each other. The finger grip 25 is provided on the exteri surface of the H shaped member 16 to enable a user to push t H shaped member inwards against the spring bias provided the resilient arm 14 to ' disengage the teeth 22, 24 and enab the sub-housing 13 and thus the lens 12 to be moved forward or rearwardly relative to the housing 11. Once the finger gr 15, actually on both sides, is released the resilient arm acts to engage the teeth 22, 24 once again so that the lens and housing 11 are fixed relative to each other. It will appreciated that another finger grip is provided on the oppo ite side of the housing 11 to the finger grip 25 shown a that the housing 11 and the resilient arm 14 are construct similarly but in the opposite sense to that shown in Figure 9 The invention further provides a detachable fan unit 50 shown in Figures 10 and 11. A fan unit 50 is generally desi able to cool the lighting unit 10 if it is in use for long p riods as the bulb 33 produces substantial heat. In Figures and 11 only the fan housing 51 is shown and the actual fan a motor unit have not been shown. The housing 11 of the lighti unit has a series of ribs 60 located across an aperture 61 the rear 62 of the housing, as shown in Figures 2 and 3, f example. The two centrally located ribs 60' each have a rece 63 formed at each end on which the fan housing 51 is locat as described below. In addition, the rear 62 of the housing 1 has a pair of spaced apart apertures 64 into which electric contacts 65 of the fan housing 51 are inserted to provi electrical power to the fan. The fan housing 51 is open at its front end 52, and a peri pheral flange 53 is provided around the front end 52. The ver tical portions 53' of the flange 53 each has a protrusion 5 of a suitable shape as to be engaged in the recesses 63 a each end of the ribs 60' at the rear of the housing 11. Th base 55 of the fan housing 51 further has a pair of electrica contacts 65 which are slidable forwardly and rearwardly, bet ween a position as shown in Figure 10 and a position in whic the contacts 65 project forwardly of the fan housing 51. Th electrical contactts 65 are connected together by a slidin grip 56 mounted on the underside of the base 55. The moto (not shown) of the fan unit, when fixed within the fan housin 51 has electrical connections which are fixed to or are i contact with the contacts 65. To locate the fan housing 51 on the housing 11, the fan hous¬ ing is located above the rear 62 of the housing 11 and in con tact with the rear 62, and then slid vertically downwards s that the protrusions 54 engage in the recesses 63 in the rib 60'. The sliding grip 56 is then moved forwards so that th electrical contacts 65 are inserted into the apertures 64 i the rear 62 of the housing 11. Thus, the electrical contac 65 when located in the apertures 64 also provide a mechanica lock for the fan housing 51, in addition to providing a mean for conveying electrical pwoer to the fan. Within th apertures 64 there are additional contacts (not shown) whic are connected to electrical circuitry in the housing 11 fo supplying power to the bulb 33 and fan unit. The electrica circuitry is controlled by means of an on/off switch 67 loca ed on the rear 62 of the housing 11. When the fan unit 50 i energised, air is forced into the housing 11 through t aperture 61 and flows outwards through an aperture 68 in th top 69 of the housing 11. The power supply for the bulb 33 an fan unit 50 may be provided by a battery or provided from mains adaptor. The light bulb 33 is operated at 12 volts an has a wattage of 30, 50, 75 or 100 watts respectively. Whe using a light bulb of 30 watts or a higher wattage bulb for few minutes only the fan may remain inoperative. When using light bulb of higher wattage or for longer periods of time t fan will be switched on. The housing 11 further has a swivel mounting 70 to enable t unit to be moved in any desired direction. Turning again to Figures 1 and 4, the front face of the su housing 13 carries pins 72 with heads 73 at the ends thereo They serve for the mounting and locking of filters, masks, a effect masks.

Claims: CLAIMS 5 1. Lighting unit comprising a housing (11) including a r flector (30) mounted within the housing (11) , a removab light source (33) fixed within the housing (11) and dispos within the region of the reflector (30) , and a focussing le (12) movably mounted on the housing (11) forwardly of t 0 light source (33) , the lens (12) at least movable between p sitions to provide floodlight and spotlight light beams. 2. Lighting unit according to claim 1, characterized i that the reflector (30) includes a part-spherical member (31 5 and is disposed slightly rearwardly of the light source (33) . 3. Lighting unit according to anyone of claims 1 and 2 characterized in that the underside of the housing (11) has a aperture (34) for receiving a holder (40) on which the ligh 0 source (33) is mounted. 4. Lighting unit according to anyone of claims 1 to 3 characterized in that the holder (40) is removably engageabl with the housing (11) , the holder (40) and the housing (11 5 having corresponding engaging means (42) for locking the hol der (40) in place. 5. Lighting unit according to anyone of claims 1 to 4 characterized in that the engaging means (42) on the holde 0 (40) are resiliently urged into locking engagement with th engaging means in the housing (11) by being fastened t resilient plastic arms (41) . 6. Lighting unit according to anyone of claims 1 to 5 5 characterized by a detachable fan unit (50) which is removabl engageable on the rear (62) of the housing (11) . 7. Lighting unit according to claim 6, characterized i that there are ribs (60) with recesses (63) at the ends there of on the rear (62) of the housing (11) , and the housing (51 of the fan unit (50) has cooperating engaging means in form o protrusions (54) . 8. Lighting unit according to anyone of claims 1 to 7 characterized in that the focussing lens (12) is fixed in sub-housing (13) slidably mounted in the housing (11) , resili ent arms (14) extending in the direction of the relative move ment between the sub-housing (13) and the housing (11) bein fastened to the sub-housing (13) , finger grips (25) bei mounted on the free ends of said arms (14) , and cooperatin teeth (22, 24) being provided on the inner side of said hous ing (11) and said resilient arms (14) . 9. Lighting unit according to claim 8, characterized i that the resilient arms (14) comprise leaf springs and th slots are provided in said housing (11) , said slots guidingl receiving said resilient arms (14) . 10. Lighting unit according to anyone of claims 8 and 9 characterized in that said leaf springs urge the teeth (22 24) in engagement with each other. 11. Lighting unit according to anyone of claims 8 to 10 characterized in that pins (72) with heads (73) at the en thereof are provided on the front face of the sub-housing (13 for mounting filters etc. thereon. 12. Lighting unit according to anyone of claims 1 to 3 characterized in. that a tube-shaped member (36) surroundi the light bulb (33) is provided in the housing (11) . 13 ' .-; ; Lighting unit according to claim 12, characterized an ' aperture (34) in the lower side of the tube-shaped memb (36) to provide access for inserting the light bulb (33) . 14. Lighting unit according to anyone of claims 1 to 1 characterized by lugs (35) inwardly projecting from the tub shaped member (36) serving as stops for the front face of t part-spherical member (31) , and a compression spring (32) b ing clamped between the inner side of the reflector (30) a said part-spherical member (31) .

Inventors: HAEHNEL WALTER, HAEHNEL, WALTER
Applicants: HAEHNEL WALTER, HAEHNEL, WALTER
Application year: 1989
Main classification: F21V17
IPC codes: F21S8