Patent Publication Number: US-2003230959-A1

Title: Refurbished video projection lamp

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention generally relates to projector lamps and more specifically relates to reconditioned or refurbished projector lamps for aircraft cabin picture projection units.  
       [0003] 2. Description of the Prior Art  
       [0004] Metal halide lamps are used in many different applications to provide a high luminous efficiency lamp for microscopes, color printers and picture projection units. These metal halide lamps have a life expectancy of 3,000 hours and are costly to replace when the lamp bums out. Accordingly, there is a need for a cheaper source of metal halide lamps. The claimed invention relates to the reconditioning or refurbishing of an expended metal halide lamp. The prior art discloses several different types of reconditioned or refurbished tubes or bulbs. However, the prior art does not disclose a reconditioned or refurbished metal halide lamp.  
       [0005] U.S. Pat. No. 3,063,777 issued to Trax discloses a method of rebuilding electron tubes and particularly a method of rebuilding cathode ray tubes wherein an internal defective part or assembly is replaced with a good part or assembly. However, this prior art reference does not disclose issues inherent in refurbishing metal halide lamps in particular.  
       [0006] U.S. Pat. No. 3,831,123 issued to Aldrich discloses a cathode ray tube-deflection yoke combination wherein the yoke is bonded to the cathode ray tube by a hot melt adhesive to effect semi-permanent adherence thereto. However, this prior art reference does not disclose issues inherent in refurbishing metal halide lamps having ceramic reflector bases.  
       SUMMARY OF THE INVENTION  
       [0007] United States Federal Aviation Administration regulations require at least one video projection unit in larger passenger aircraft so that the aircraft will have at least one means of conveying information to passengers aboard the aircraft. One of the more common types of picture projection units is a single lens unit made by Hughes-Avicom International using a metal halide lamp assembly manufactured by Matsushita Avionics Systems Corporation. The projector lamp within each of these projection units typically burn out after 1,000 hours of use and are very expensive to replace. Historically, these projector lamps have been discarded and replaced by a new projector lamp.  
       [0008] The claimed invention relates to refurbishing these projector lamps enabling the projector lamps to be used again. An object of the claimed invention is to provide a refurbished or reconditioned metal halide projector lamp assembly.  
       [0009] Another objective of the claimed invention is to provide an operable projector lamp assembly at a reduced cost.  
       [0010] A further objective of the claimed invention is to reuse elements of projector lamp assemblies that were previously discarded.  
       [0011] To achieve the foregoing objectives, and others that will become evident after a reading of this specification and viewing of the appended claims and drawings, a refurbished projector lamp assembly is provided. The refurbished projector lamp assembly generally comprises a lamp assembly housing sized and shaped to mount within an aircraft cabin picture projection unit and a lamp assembly seated within the housing. The lamp assembly is generally made up of a parabolic reflector, a reflector base, an operable lamp, a layer of previously applied ceramic cement, a newly applied layer of ceramic cement, a connecting wire and a power connection plug.  
       [0012] The parabolic reflector is made of glass and is seated within the housing. The reflector has an inner reflective surface for reflecting the light emitted from the lamp and a centrally located receiving aperture for receiving the lamp.  
       [0013] The ceramic reflector base connected to an outer surface of the reflector has a mounting aperture axially aligned with and adjacent to the receiving aperture. The mounting aperture is sized and shaped to receive the lamp and the ceramic cement.  
       [0014] The lamp is sized and shaped to fit through the receiving aperture and the mounting aperture so as to leave a gap between the lamp and the mounting aperture. A previously applied layer of ceramic cement partially fills the gap between the mounting aperture and the gap is completely filled by a newly applied layer of ceramic cement adjacent the previously applied layer holding and centering the lamp horizontally and vertically within the receiving aperture.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0015]FIG. 1. FIG. 1 shows a perspective view of the lamp assembly.  
     [0016]FIG. 2. FIG. 2 shows a cross sectional view of the lamp assembly.  
     [0017]FIG. 3. FIG. 3 shows a front view of the lamp assembly.  
     [0018]FIG. 4. FIG. 4 shows a back view of the lamp assembly.  
     [0019]FIG. 5. FIG. 5 shows how the lamp is removed from the reflector base.  
     [0020]FIG. 6. FIG. 6 shows how the remainder of the lamp is removed from the reflector base.  
     [0021]FIG. 7. FIG. 7 shows a cross sectional view of the refurbished lamp assembly.  
     [0022]FIG. 8. FIG. 8 shows a perspective view of the projector lamp assembly.  
     [0023]FIG. 9. FIG. 9 shows a cross sectional view of the butt splice connection.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0024] Turning now to the drawings, a refurbished projector lamp assembly  10  for use in a picture projection unit originally manufactured by Matsushita Avionics Systems Corporation, a corporation with offices located at 22333 29 th  Drive S.E., Bothell, Wash. 98021, is shown in FIG. 8. The picture projection units are typically sold under several different brand names such as Hughes Avicom International and Rockwell Collins. The refurbishment of the projector lamp assembly  10  discloses a preferred embodiment of the claimed invention. The refurbished structure shown in the drawings and described in this specification can be created in other lamp assemblies used in other applications.  
     [0025] The projector lamp assembly  10  shown in FIG. 8 generally comprises a lamp assembly housing  20  and a metal halide lamp assembly  30 . The metal halide lamp assembly  30  shown in FIGS. 7 and 8 generally comprises a parabolic reflector  40 , a reflector base  50 , an operable lamp  60 , a layer of previously applied ceramic cement  70 , a newly applied layer of ceramic cement  80 , a connecting wire  90  and power connection plug  100 .  
     [0026] The lamp assembly housing  20  shown in FIG. 8 is preferably manufactured by Matsushita Avionics Systems Corporation and is sized and shaped to mount within an aircraft cabin picture projection unit made by Matsushita Avionics Systems Corporation by two diagonally spaced mounting screws  110  (one not shown) located at two comers of the housing  20 . The housing  20  has a flat lens  120  retained adjacent a circular opening  130  of the housing  20  by two retention screws  140  (one not shown). The side wall  150  of the housing  20  has a clamp  160  to hold the power connection plug  100  in place against the side wall  150  aligning the power connection plug  100  with the power outlet from the projection unit. The power connection plug  100  provides power to the lamp assembly to illuminate the lead within the lamp assembly. The lamp side of the circular opening  130  in the housing  20  has a flat surface for seating the parabolic reflector  40  against the housing  20 . A spring clip  180  is used to hold the lamp assembly  30  against the lamp assembly housing  20 .  
     [0027] The parabolic reflector  40  seated within the lamp assembly housing  20  as shown in FIG. 8 is made of glass approximately ⅛ inch thick and has a reflective coating  190  on the inner surface of the reflector  40  to reflect light emitted by the lead  200  within the lamp  60 . The reflector  40  as shown in FIGS.  1 - 8  is preferably about 3 and {fraction (5/16)} inches in diameter and about 1 and ⅝ inches in depth. The reflector  40  has a centrally located receiving aperture  210  about ⅝ inch in diameter and a connecting wire aperture  220  about ⅜ inch in diameter as shown in FIG. 2. FIGS.  3 - 4  show a front and back view of the reflector  40 .  
     [0028] The ceramic reflector base  50  as shown in FIGS. 4, 5, and  7  is preferably about 1 and ⅜ inches in diameter and has a step  230  of about ¾ inch in diameter with a mounting aperture  240  of about ½ inch in diameter that is designed to be axially aligned with the receiving aperture  210  of the parabolic reflector  40  when the reflector base  50  is connected to the reflector  40 . The mounting aperture  240  is sufficiently sized to receive the lamp  60 , the previously applied layer of ceramic cement  70 , and the newly applied layer of ceramic cement that mounts the lamp  60  within the mounting aperture  240  as shown in FIG. 7.  
     [0029] During the original manufacture of the lamp assembly  250  shown in FIGS. 1 and 2, the lamp  260  is first mounted within the reflector base  50  and the reflector base  50  is then in turn affixed to the outer side  270  of the parabolic reflector  40  such that the lamp  260  is properly centered within the receiving aperture  210 . In order for the lamp assembly  250  to function properly during use, the lamp  260  has to be centered within the receiving aperture  210  of the parabolic reflector  40  so that the light emitted by the lead  200  is reflected correctly off of the reflective coating  190  within the parabolic reflector  40 . The lamp  260  is mounted within the mounting aperture  240  with a layer of ceramic cement  70  fixing the relationship of the lamp  260  to the mounting aperture  240 . The lamp  260  is then placed through and centered within the receiving aperture  210 . The reflector base  50  is then fixed to the outer surface  270  of the parabolic reflector  40  with ceramic cement  280  to maintain the centered relationship between the lamp  260  and the receiving aperture  210 .  
     [0030] The lead  200  is originally one continuous piece coming from the manufacturer, beginning with a lead end  290  extending through the filament  300 . At the tip  310  of the filament  300 , the lead  200  is then bent and fed through the connecting wire aperture  90  where it is connected to the return power wire  320  as shown in FIG. 1. Previously, refurbishment of the assembly  250  was thought not to be possible due to the fact that the one-piece lead  200  would have to be severed so that the lamp  260  could be replaced after the lamp  260  had burned out. It was state of the art thought at the time of the claimed invention that if the lead  200  was severed adjacent the tip  310  of filament  300  so as to leave the remaining part of the lead  200  that extended through the connecting wire aperture  220  intact, a solder connection would have to be made between the replacement lamp and the remaining part of the lead to complete the electrical circuit.  
     [0031] The necessity of having a soldered connection between the remaining part of the lead and the lead of anew lamp presented an obstacle to the refurbishment of the assembly due to the fact that performing a soldering process on the lead ends would cause permanent damage to the lead ends and the filament. Therefore, it was previously thought that assemblies of this type were not reusable. When the original lamp burns out, the projector lamp assembly was previously removed and replaced with a new projector lamp assembly at a cost in excess of $1,000.00, making the maintenance of projection unit of this type very expensive.  
     [0032] However, significantly, applicant has discovered after 3 to 4 months of contemplation and testing that the projector lamp assemblies can be refurbished by utilizing a mechanical crimp butt splice  330  to connect the remaining portion of the original lead, termed the connecting wire  90  when describing the refurbished assembly  30 , to the lead  340  of the replacement lamp  30  as shown in FIGS. 7 and 9. The butt splice  330  is preferably accomplished by using a butt splice connector  350  having part number TCLP0412 manufactured by AMP Incorporated of Harrisburg, Pa. 17105. The butt splice connection  330  was tested and determined that the connection withstood normal operating conditions.  
     [0033] To reduce the expense in maintaining projection units of this type, the claimed invention provides a refurbished or reconditioned lamp assembly  30  that can be reused at a fraction of the original cost. This is accomplished by removing the burned out lamp  260  from the lamp assembly  250  and replacing it with a new lamp  60  as shown in FIGS. 5 and 6.  
     [0034] The lamp  60  used in the refurbished projector lamp assembly  10  as shown in FIGS.  7 - 8  is preferably made by Hamamatsu Corporation, a corporation with offices located at 360 Foothill Road, Bridgewater, N.J. 08807 and has a part number L4342. However, it is contemplated as being within the scope of the claimed invention that other types of lamps can be used in the refurbishment of the preferred embodiment depending upon the particular appication. Metal halide lamps produce illumination by sparking across an air gap within the filament of the lamp. Lamp assemblies are manufactured with different air gap sizes to meet different application requirements, ranging from about 1.5 mm to 5.0 mm. The lamp  60  is constructed to operate on 150 Watts of power and is capable of emitting 76 lm/W. The lamp  60  fits through the receiving aperture  210  and the mounting aperture  240  leaving a gap  360  between the lamp  60  and the mounting aperture  240  for the placement of newly applied layer of ceramic cement  80  between the lamp  60  and the mounting aperture  240 .  
     [0035] The reconditioned projector lamp assembly  10  is constructed by first removing the nut  370  from the rear of the lamp assembly  250  and disconnecting the lead power wire  380  shown in FIGS. 1 and 5. The clamp  160  holding the power connection plug  100  is then removed by removing the screw  390  securing the clamp  160  to the side wall  150  of the housing  20  shown in FIG. 8. The spring clip  180  holding the lamp assembly  250  is then removed allowing the lamp assembly  250  to be removed from the lamp assembly seat  170 . The lead  200  of the original lamp  260  is then cut as shown in FIG. 5. The lamp assembly is now in condition to be refurbished.  
     [0036] The lamp assembly  250  is refurbished or reconditioned by first covering the filament  300  with a cloth and snapping the filament  300  off as close to the connection between the ceramic cement  70  and the filament  300  as possible as shown in FIG. 5. FIG. 6 shows a {fraction (5/16)} inch hole  400  is then drilled through the center of the reflector base  50  removing ceramic cement  70  holding the base of the filament  300  and the base of the filament  300  still remaining within the mounting aperture  240  as shown in FIG. 6. The lamp assembly is then cleaned of with isopropanol alcohol for replacement of the lamp.  
     [0037] A new layer of ceramic cement  80  is then placed around the base  410  of the new lamp  60 . Preferably, Resbond 940 LE Adhesive made by Cotronics Corporation, a company having offices at 3379 shore Parkway, Brooklyn, N.Y. 11235 is used to hold the new lamp  60  in place within the drilled hole  400 . However, it is contemplated as being within the scope of the claimed invention that other types of adhesive cements can be used to accomplish similar results. The Resbond 940 LE adhesive is used due to the fact that the adhesive is capable of withstanding operating temperatures of up to 2500 F. This is important in that the operating temperature of the lamp assembly can reach 1200 F. Therefore, it is important to select an adhesive that bonds to ceramic and can withstand high temperatures. The Resbond 940 LE was selected to provide a wide factor of safety in the refurbishment and operation of the refurbished lamp. The lamp is then inserted through the {fraction (5/16)} inch hole  400  and centered within the receiving aperture  210  with respect to the parabolic reflector  40  so that the tip  415  of the lamp  60  protrudes approximately ¼ inch out of the reflector  40 . The lamp assembly  30  is then placed in a curing table having a round bore sized hole to receive the parabolic reflector  40  so that the ceramic cement  80  can cure with the lamp  60  in the proper position for a time period of 4 to 8 hours.  
     [0038] The lens  120  is then cleaned with a lens cleaning solution and the lead power wire  380  is connected to the lead end of the new lamp  60  with nut  370 . The lead  340  of the new lamp  60  is then cut so that it meets the connecting wire  90  (the remaining portion of the original lead  200 ) that is connected to the return power wire  320 . The tip  420  of the lead  340  is then butt spliced to the connecting wire  90 , preferably using a TCLP0412 butt splice connector  330  made by AMP Corporation with an appropriate crimping tool such as AMP crimping tool #4667.  
     [0039] The lamp assembly  30  is then inserted back into the lamp assembly housing  20  making sure that the reflector detent  430  matches the detent notch in the lamp assembly housing  20 . The power connection plug  100  is then clamped in place by the clamp  160  holding the power connection plug  100  against the side wall  150  of the housing  20 . The spring clip  180  that holds the lamp assembly  30  in place is then reattached.  
     [0040] The projector lamp assembly  10  is then tested in accordance with acceptance test procedure ATP MAS 150LMP created by Applicant. The lamp has been correctly reconditioned if the attributes of the projector lamp assembly fall within the following ranges at two minutes of operation: 11,000 to 12,500 lumens, 1.8 to 1.95 amps, and 80-105 volts.  
     [0041] Although the invention has been described by reference to some embodiments it is not intended that the novel device be limited thereby, but that modifications thereof are intended to be included as falling within the broad scope and spirit of the foregoing disclosure, the following claims and the appended drawings.