Electronic Flash Assemblage With Reflector to Circuit Board Connection

The invention relates generally to the field of photography, and in particular to an electronic flash assemblage for a camera.

Most modern electronic flash units use a triggering electrode method of flash firing. In this type of circuit, a main capacitor is connected permanently across two terminals of a glass flash tube filled with inert xenon gas. The resistance of the gas in the flash tube is normally too high to permit a direct discharge. For firing the flash unit there is a third electrode--for example, a coil of wire wound around the outside of the flash tube. An instantaneous triggering voltage of about 5000 volts applied to the coil of wire ionizes the gas in the tube, thus lowering the resistance of the gas and allowing the main capacitor to discharge its energy through the tube in the form of a intense flash of light. The triggering voltage is usually supplied by a trigger or ignition coil connected to a small capacitor.

Instead of winding the coil of wire around the outside of the flash tube, the tube can be supported with its outside directly against the inner wall of an electrically conductive flash reflector that is connected to the trigger coil as mentioned in U.S. Pat. No. 3,484,597, issued Dec. 16, 1969, and U.S. Pat. No. 4,570,203, issued Feb. 11, 1986. In this instance, the flash reflector serves as a light reflector and as a triggering electrode. Typically, a piece of wire or metal tape has one end soldered to a circuit board, which includes the trigger coil, and another end secured to the flash reflector. Ways are continuously being devised to simplify manufacture and design of the flash unit.

According to the invention, an electronic flash assemblage comprising a circuit board having an exposed electrically conductive patch, and an electrically conductive flash reflector adapted to be attached to the circuit board, is characterized in that:

the flash reflector has a resilient electrically conductive extension which protrudes from the flash reflector to cause it to be deformed against the conductive patch when the flash reflector is attached to the circuit board, whereby the resilient extension will be inherently biased against the conductive patch to make an electrical connection between the conductive patch and the flash reflector. Thus, a simpler arrangement without the need for soldering as in the prior art is achieved.

FIG. 1 is an exploded perspective view of an electronic flash unit according to a preferred embodiment of the invention, showing the flash unit partially disassembled; and

FIG. 2 is an assembled perspective view of the flash unit.

The invention is disclosed as being embodied preferably in an electronic flash unit for a camera. Because the features of an electronic flash unit are generally known, the description which follows is directed in particular only to those elements forming part of or cooperating directly with the disclosed embodiment. It is to be understood, however, that other elements may take various forms known to a person of ordinary skill in the art.

Referring now to FIGS. 1 and 2 of the drawings, an electronic flash assemblage 10 is shown to have several components that can be assembled to form a flash unit. A printed circuit board 12 has an electrically conductive patch which is an exposed metal strip 14. A known trigger or ignition coil 16 has four identical mounting pins 18 which are intended to be inserted through four corresponding pin-holes 20 in the circuit board 12 and to be held fast by respective solder caps 22, to attach the trigger coil to the circuit board. One of the solder caps 22 is located on one end 24 of the metal strip 14 to electrically connect the trigger coil 16 to the metal strip. An electrically conductive flash reflector 26 is intended to be placed in a rectangular opening 28 in the circuit board 12 and a pair of integral hooks 30 of the flash reflector fit into respective holes 32 in the circuit board, to attach the flash reflector to the circuit board. The flash reflector 26 has a pair of resilient, i.e. springy, electrically conductive, integral extensions 34 which protrude from the flash reflector to cause them to be deformed against another end 36 of the metal strip 14 when the flash reflector is attached to the circuit board 12. See FIG. 2. Thus, the pair of resilient extensions 34 will be inherently biased or urged against the end 36 of the metal strip 14 to make an electrical connection to that end without the need for soldering. Preferably, the pair of resilient extensions 34 have respective flat contact ends 38 and respective curved flexure (deformable) joints 40.

A transparent flash cover 42 is intended to be placed over the flash reflector 26, and attached to the circuit board 12 by inserting a pair of integral hooks 44 of the flash cover into respective cut-outs 46 in the circuit board. See FIGS. 1 and 2. An integral resilient finger 48 of the flash cover 42 is adapted to firmly press the contact ends 38 of the resilient extensions 34 firmly against the end 36 of the metal strip 14 as shown in FIG. 2.

After the flash reflector 26 is attached to the circuit board 12, a known glass flash tube 50 filled with inert xenon gas is positioned with its outside directly against an inner concave side of the flash reflector as shown in FIG. 2. A pair of resilient electrically conductive supports 52 each have one end 54 soldered to the circuit board 12 and another end 56 soldered to respective terminals or leads 58 of the flash tube 50. The ends 54 are electrically connected to a main capacitor, not shown, and the ends 56 serve to urge the flash tube 50 into intimate contact with the inner concave side of the flash reflector 26.

The invention has been described with reference to a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention.

10. flash assemblage

12. circuit board

14. metal strip

16. trigger coil

18. mounting pins

20. pin-holes

22. solder cap

24. strip end

26. flash reflector

28. rectangular opening

30. hooks

32. holes

34. resilient extensions

36. strip end

38. contact ends

40. flexure joints

42. flash cover

44. hooks

46. cut-outs

48. resilient finger

50. flash tube

52. resilient supports

54. support end

56. support ends

58. terminals