Abstract:
A heating element (IC, transistor or the like) is placed on a printed circuit board and silicon grease is coated on the surface of the printed circuit board side of the heating element. The projection portion of a radiator with a step portion is inserted into the through hole of the printed circuit board and closely contacted with the lower portion of the heating element through the silicon grease. As a result, heat generated from the heating element is transferred to the projection portion of the radiator through the silicon grease and then transferred to the entirety of the radiator. Excessive silicon grease is collected in a step portion provided at the base of the projection portion of the radiator and prevented from leaking to other portion such as a portion on the board.
Abstract:
In general, in one aspect, the invention features a connection between a through-hole in a circuit board and a contact region on a component. The contact region has a surface bearing a depression. A continuous solder column has one end of that forms a solder joint with an inner wall of the through-hole and the other end of that forms a solder joint with the contact region.
Abstract:
A capacitor element has on its outer surface a cathode layer with a flat bottom surface, and also a tantalum lead extending outward from its one end. One of opposing major surfaces of a flat cathode terminal is located beneath and in parallel with the bottom surface of the cathode layer. They are electrically connected with each other. One of opposing major surfaces of a flat anode terminal is located substantially in the same plane as the one major surface of the cathode terminal and is electrically connected to the tantalum lead of the capacitor element. The capacitor element, the anode terminal and the cathode terminal are encapsulated with portions of the other major surfaces of the cathode and anode terminals left exposed.
Abstract:
An assembly including a printed-circuit electronics card mounted on a metal substrate, and in electronic communication with the same, includes a capsule which is crimped into a cavity in the metal substrate and which extends through a hole in the electronics card, the edges of said hole being metallised, the capsule being soldered to the metallised area of the edges.
Abstract:
A transformer group in which a multitude of transformers are used to supply energy to a single load. The transformers are connected in series; in order to assist in providing a "flux equalizing" affect, the invention includes a flux equalizer circuit. The flux equalizer circuit provides a series of flux windings. Each flux winding is associated with a single transformer. The windings are arranged in parallel. In this manner, a balancing of the output of the transformers is obtained; the power output from each transformer is "sensed" by its associated flux winding which is "shared" with the other transformers via their own associated flux winding. Power is process then through the secondary windings, rectifiers, and output filters to a common load.
Abstract:
In a film carrier with a conductive circuit formed, an opening is formed in a particular position relative to where the conductive path is to be formed. The opening is a through-hole, filled with a conductive material to form a conductive path. The conductive circuit has a concave face, provided according to certain formulae. The film carrier can cope with a fine-pitched and highly dense mounting, while prohibiting pulling out of the conductive path by an external force. The film carrier does not suffer from fallout of the conductive path, and has increased electrical connection reliability.
Abstract:
A BGA-type semiconductor device has a soldering bump a soldered state of which can be easily checked by visual inspection. A package has a bottom surface which faces the wiring board when the semiconductor device is mounted on the wiring board. A plurality of soldering bumps are provided on the bottom surface of the package. The soldering bumps are in a plurality of different sizes, and are located in positions where the soldering bumps are observable from outside of the package when the semiconductor device is mounted on the wiring board.
Abstract:
A manufacturing method for a TAB tape which forms a plurality of bumps on a plurality of sheet-like leads of the TAB tape. First, the leads are fixed to a belt-shaped tape member having a plurality of first openings arranged at equal intervals in a longitudinal direction and a plurality of second openings formed around each of the first openings. In fixing each lead to the tape member, one end portion of the lead is exposed to each first opening, and the other end portion of the lead is exposed to each second opening. Secondly, a point is pressed onto a surface of each lead to form a plurality of recesses on the surface of each lead. Thirdly, a metal ball is seated in each recess, and is then heated to be molten so that a part of the metal ball may substantially semispherically project from the surface of the lead. Thus, a metal bump is formed as a substantially semispherical part projecting from the surface of each lead. Instead of the use of the metal ball, a mixture of a metal powder and a paste may be filled in each recess. In this case, the mixture filled in each recess is heated to be molten so that a part of the mixture may substantially semispherically project from the surface of each lead, thus forming the metal bumps on the surface of each lead.
Abstract:
A fabrication method of a printed wiring board in which the halation effect of light irradiated to a solder resist film is utilized in a process of selectively removing the solder resist film. After a conductive layer is patterned to a given circuit pattern including soldering pads, the solder resist film is formed on the base material to cover the patterned conductive layer. The solder resist film is selectively exposed to light utilizing reflection of the irradiated light from the insulating base material and developed so that the solder resist film is selectively left in areas adjacent to the respective soldering pads. Then, an etching resist film is formed to cover the patterned conductive layer except for the soldering pads, and surface areas of the respective soldering pads are selectively etched using the etching resist film as a mask to produce solder resist dams made of the solder resist film left on the base material. Solder films are formed on the respective soldering pads thus selectively etched. Electronic components can be soldered on the soldering pads with satisfactory reliability even if the soldering pads have narrow pitches such as 500 .mu.m or less.
Abstract:
The invention relates to a printed circuit board disposed on a film serving as the carrier material. A connector strip having a large number of connection pins is disposed on the printed circuit board using surface-mounting technology. Connector strips of this type are widespread in digital technology. In the case of circuits in the fields of power electronics or motor vehicle electronics, connector strips cannot be surface-mounted because of the larger cross-sections of the connections. In a printed circuit board of the type mentioned at the outset, recesses are provided in the film stiffener underneath the solder points, such that when the connection pins of the connector strip are soldered, level differences in the connection pins are compensated by the deformation of the carrier film. With this measure, tensions are compensated for the most part by the deformation of the carrier film, so that connector strips for power electronics and motor vehicle electronics applications can also be surface-mounted.