Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – Connection to lamp or electron tube
Reexamination Certificate
1999-12-01
2001-08-07
Patel, Tulsidas (Department: 2839)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
Connection to lamp or electron tube
Reexamination Certificate
active
06270355
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a lamp bulb device installed on a board, in which lead wires of a non-capped lamp bulb are connected to lands of a printed wiring board by soldering to install the lamp bulb device on the printed wiring board, and more particularly, to a lamp bulb device installed on a board, in which lead wires of the lamp bulb device are connected to lands of a printed wiring board by soldering according to either flow soldering means or reflow soldering means.
2. Description of the Prior Art
A lamp bulb device installed on a board of this kind in a prior art is configured such that a lamp holder is formed on an upper surface of the device as one body, and lead wires exposed to the outside through a side surface end of a base are connected to lands of a printed wiring board by soldering as disclosed in Japanese Utility Model Publication (kokoku) No. Hei 5-11649 (1993), or otherwise, that a squeezed seal portion of a non-capped lamp bulb is inserted into a substantially rectangular parallelepiped-shaped base having a lamp insertion hole having an open top, and lead wires exposed to the outside through a side surface of the base are pressed in a flat shape to extend parallel to a bottom of the base and are then connected to lands of a printed wiring board by soldering as disclosed in Japanese Utility Model Laid-open (kokai) No. Hei 3-94763 (1991).
The lamp bulb device installed on the board as described in the prior art has the problems that since terminals of the lamp bulb device and lands are connected together by soldering on the outside of the side surface of the base, the lamp bulb device is packaged without being in contact with the base portion, and as a result, packaging density is lowered, while a short soldered portion of the lead wire degrades reliability in connection.
SUMMARY OF THE INVENTION
An object of the present invention, which may be defined in embodiments 1 to 9, is to improve packaging density by adapting a bottom of a base portion for a connection portion, and another object of the present invention, which may be defined in embodiments 1 to 11, is to provide more secure connection by enlarging an area of the connection portion.
According to the present invention as defined in embodiment 1, there is provided a lamp bulb device installed on a board, composed of a non-capped lamp bulb having lead wires and a base portion for supporting a cylindrical bottomed holder (the bottom is a part of the base portion) having a lamp insertion hole (the interior of the holder) permitting insertion of the non-capped lamp bulb therein and structured such that lead-wire outlet holes are provided substantially in the center of the base portion to draw out the lead wires toward a lower surface of the base portion, and the lead wires drawn out through the lead-wire outlet holes are connected electrically to lands of a printed wiring board by soldering, wherein lead-wire guide grooves (recesses) are provided on the lower surface of the base portion to communicate with the lead-wire outlet holes, lead-wire insertion grooves (recesses) are provided on a side surface of the base portion to communicate with the lead-wire guide grooves, lead-wire fixing grooves (recesses) (respectively having open tops permitting lead-in of the lead wires, for example) are provided on the inside of the base portion to communicate with the lead-wire insertion grooves, the lead wires drawn out from the non-capped lamp bulb through the lead-wire outlet holes are led to the lead-wire fixing grooves through the lead-wire guide grooves after passage through the lead-wire insertion grooves, and the lead wire portions within the lead-wire guide grooves are connected electrically to the lands of the printed wiring board by soldering.
According to the present invention as defined in embodiment 2, when an outer edge of each lead-wire guide groove is cut to provide an upward hollow step portion, molten solder is allowed to be wet along a side surface of each lead wire upwards in case of soldering according to reflow soldering means, resulting in more firm connection.
The lead wire is positioned along the center line of each lead-wire guide groove on condition that a width W
1
of each lead-wire guide groove and a width W
2
of each insertion groove are determined to satisfy W
2
<W
1,
and a width D of each lead wire is determined to satisfy W
1
≧2D.
According to the present invention as defined in embodiment 4, the length of lead wires used is reduced by forming the lead-wire fixing grooves as grooves opening to the left and right side surfaces of the base portion, resulting in a reduction of device cost.
According to the present invention as defined in embodiment 5, when the lead wires within the lead-wire guide grooves are pressed in a flat belt-like shape and are then dipped into molten solder, the solder stands up above the center of the lead wires, providing a plating thickness of about 10 microns. Further, a melting speed of solder is improved by the use of a linear groove provided on the surface to be coated with solder.
According to the present invention as defined in embodiment 8, it is possible to obtain satisfactory solderability on condition that a depth H of each lead wire guide groove, a thickness T of each lead-wire guide groove, a thickness T of each lead-wire within the lead-wire guide groove and a thickness t of cream solder printed on the land of the printed wiring board are determined to satisfy H≦T+t/2.
According to the present invention as defined in embodiment 9, leg pieces may be provided opposite to each other through the lead wires at an interval larger than a width of each lead-wire insertion groove on the lower surface of the flat base portion without providing the lead-wire guide grooves on the lower surface of the base portion.
According to the present invention as defined in embodiment 10, there is provided a lamp bulb device installed on a board and composed of a non-capped lamp bulb having lead wires and a base portion for supporting a cylindrical bottomed holder (the bottom is a part of the base portion) having a lamp insertion hole (the interior of the holder) permitting insertion of the non-capped lamp bulb, wherein lead-wire outlet holes are provided substantially in the center of the base portion to draw out the lead wires toward the lower surface of the base portion, a pair of projections are provided in a sideward projecting shape on both the left and right sides of the base portion, lead-wire fixing grooves are provided on the lower surface of the base portion to fix the lead wires drawn around the lower surface side from the outside corners of the projections, the lead wires drawn out through the lead-wire outlet holes are laid between the projections through the lower surface of the base portion, and lead wire portions are laid between the projections are connected electrically to lands of a printed wiring board by soldering.
According to the present invention as defined in embodiment 11, there is provided a lamp bulb device installed on a board and composed of a non-capped lamp bulb having lead wires and a cylindrical bottomed holder (the bottom is a part of the base portion) having a lamp insertion hole (the interior of the holder) permitting insertion of the non-capped lamp bulb and lead-wire outlet holes provided in a bottom surface, wherein a pair of flanges are provided opposite to each other at symmetrical positions on the side of the lower circumference of the cylindrical bottomed holder, lead-wire winding portions are provided respectively on the flanges to extend in directions opposite to each other, the lead wires drawn out from the non-capped lamp bulb are led from the lower surface side of the flange portions and are then wound around the lead-wire winding portions, and lead wire portions wound around the lead-wire winding portions are connected electrically to lands of a printed wiring board by soldering.
The foregoing and other objects and features of the invention will become
Harison Toshiba Lighting Co., Ltd.
Knobbe Marten Olson & Bear LLP
Patel Tulsidas
Webb Brian S.
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