Abstract: A structure of the present invention has a printed circuit board having a land portion provided on a surface thereof on which a solder paste is printed in such a condition that, with respect to a lengthwise direction of a connecting terminal of an electronic component to be connected to the land portion, the solder paste projects outward from an edge of the land portion on the side of a front end of the connecting terminal and/or the solder paste is withdrawn toward inside the edge of the land portion on the side of a rear end of the connecting terminal. Solder projecting from the edge of the land portion on the side of the front end of the connecting terminal is used for forming a fillet by which the front end of the connecting terminal is surely covered. Also, as the solder paste is withdrawn from the edge of the land portion on the side of the rear end of the connecting terminal, any extra solder except for the solder indispensable for forming a soldered joint is not generated.

Abstract: A method of packaging an electronic component having electrodes soldered on lands on a printed circuit board uses a mask pattern that corresponds to the lands onto which solder paste is deposited. Solder paste is printed on the lands using the mask which has a convex shape such that the edges of the solder paste lie inside the edges of the lands. The electrodes are then placed on the solder paste, and the solder paste is caused to reflow to solder the electrodes to the lands.

Abstract: An electronic component that is provided with leads at a narrow pitch that are plated with solder is packaged by soldering the leads to lands on a printed circuit board on which the lands have been formed in a pattern of arrangement that corresponds to said leads. When packaging, solder paste is printed over areas on the lands that are greater in area than the area of the lands. The leads are then placed on this solder paste, and the solder paste is subjected to reflow to solder the leads onto the lands.

Abstract: A method of manufacturing a mount structure according to the present invention which forcedly cools down a melted solder paste on a printed circuit board at a cooling speed of 1.5° C./second or higher to solidify the solder paste when an electronic part is mounted on the printed circuit board by reflow processing.

Abstract: A printing mask has protrusions having through holes defined therein for printing a solder paste on lands on a printed circuit board. The protrusions serve to increase the amount of solder paste filled in the through holes.

Abstract: The solder paste printing method of the present invention mounts a solder paste containing therein as a solder material a Sn—Zn system solder on a mask, and urges the solder paste to make rolling over the mask from one end thereof toward the opposite thereof by means of a squeegee to thereby fill the solder paste into apertures formed in the mask. At this time, by maintaining moisture contained in the atmosphere surrounding the solder paste at a value equal to or less than a predetermined value, as the solder paste is suppressed from causing an increase in the viscosity thereof due to the reaction with the moisture in the surrounding atmosphere during the solder paste printing process, the rolling ability of the solder paste during the printing process can be kept, and attachment of the solder paste to the squeegee can be prevented.

Abstract: In a circuit board having lands 2 each of which has a through hole 4 through which a lead of an electrical part is inserted, the lead 3 and the land 2 being mounted in the circuit board by using lead-free solder 6, the width of the land 2 corresponding to the difference in radius between the land 2 and the through hole 4 is set to about 0.40 mm or more. The width of the land 2 is set to such a value that the land exfoliation due to the solidification/shrinkage of the lead-free solder 6 and the shrinkage of the circuit board in the thickness direction can be prevented. The circuit board 1 has circuit wires at least on both the surface and the back surface.

Abstract: A method of manufacturing a mount structure according to the present invention which forcedly cools down a melted solder paste on a printed circuit board at a cooling speed of 1.5° C./second or higher to solidify the solder paste when an electronic part is mounted on the printed circuit board by reflow processing.

Abstract: An electronic component that is provided with leads at a narrow pitch that are plated with solder is packaged by soldering the leads to lands on a printed circuit board on which the lands have been formed in a pattern of arrangement that corresponds to said leads. When packaging, solder paste is printed over areas on the lands that are greater in area than the area of the lands. The leads are then placed on this solder paste, and the solder paste is subjected to reflow to solder the leads onto the lands.

Abstract: A printing mask has protrusions having through holes defined therein for printing a solder paste on lands on a printed circuit board. The protrusions serve to increase the amount of solder paste filled in the through holes.

Abstract: An electronic component having electrodes is packaged on a printed circuit board on which lands are formed in a pattern of arrangement that corresponds to the electrodes by soldering the electrodes to the lands. Solder paste is printed on the lands in a shape such that the edges of the solder paste lie inside the edges of the lands. The electrodes are then placed on the solder paste, and the solder paste is caused to reflow to solder the electrodes to the lands.

Abstract: A structure of the present invention has a printed circuit board having a land portion provided on a surface thereof on which a solder paste is printed in such a condition that, with respect to a lengthwise direction of a connecting terminal of an electronic component to be connected to the land portion, the solder paste projects outward from an edge of the land portion on the side of a front end of the connecting terminal and/or the solder paste is withdrawn toward inside the edge of the land portion on the side of a rear end of the connecting terminal. Solder projecting from the edge of the land portion on the side of the front end of the connecting terminal is used for forming a fillet by which the front end of the connecting terminal is surely covered. Also, as the solder paste is withdrawn from the edge of the land portion on the side of the rear end of the connecting terminal, any extra solder except for the solder indispensable for forming a soldered joint is not generated.

Abstract: There is disclosed a method of mounting electronic parts with Sn—Zn solder which is Pb-free solder without a reduction in the bonding strength. A printed circuit board for mounting electronic parts with Pb-free solder comprises a printed circuit board whose surface is treated with Ni/Au, having an interconnection pattern of copper foil, a plated layer of Ni disposed on a surface of the copper foil, and a plated layer of Au disposed on a surface of the plated layer of Ni. The plated layer of Ni on the surface of copper foil serves as a barrier layer which prevents a Cu—Zn reaction layer, which would otherwise tend to reduce the bonding strength, from being produced in the soldered joints, when electronic parts are mounted on the printed circuit board using the Sn—Zn solder.

Abstract: The solder paste printing method of the present invention mounts a solder paste containing therein as a solder material a Sn—Zn system solder on a mask, and urges the solder paste to make rolling over the mask from one end thereof toward the opposite thereof by means of a squeegee to thereby fill the solder paste into apertures formed in the mask. At this time, by maintaining moisture contained in the atmosphere surrounding the solder paste at a value equal to or less than a predetermined value, as the solder paste is suppressed from causing an increase in the viscosity thereof due to the reaction with the moisture in the surrounding atmosphere during the solder paste printing process, the rolling ability of the solder paste during the printing process can be kept, and attachment of the solder paste to the squeegee can be prevented.

Abstract: In a circuit board having lands 2 each of which has a through hole 4 through which a lead of an electrical part is inserted, the lead 3 and the land 2 being mounted in the circuit board by using lead-free solder 6, the width of the land 2 corresponding to the difference in radius between the land 2 and the through hole 4 is set to about 0.40 mm or more. The width of the land 2 is set to such a value that the land exfoliation due to the solidification/shrinkage of the lead-free solder 6 and the shrinkage of the circuit board in the thickness direction can be prevented. The circuit board 1 has circuit wires at least on both the surface and the back surface.

Abstract: A sealing resin mixed with filler is used to seal a space between a flip-chip mounted semiconductor device and a printed circuit board. An integrated circuit chip joined to the printed circuit board by metal bumps, has the sealing resin interposed in the space between the chip and the board. The density of the filler in the sealing resin varies such that there is a relatively greater amount of filler at or near the integrated circuit chip. This allows the coefficient of thermal expansion of the resin layer adjacent the chip to better match the coefficient of thermal expansion of the silicon which makes up the chip.

Abstract: When pressure in any one of tires of a vehicle becomes abnormally low, the tire pressure detecting device detects it and gives a warning to a driver. The tire pressure detection is solely performed based on a value calculated by an on-board micro computer from wheel speeds of each wheel sensed by wheel speed sensors. The calculated value to be used for the tire pressure detection must represent correctly the tire pressure. Whenever the calculated value has a possibility to misrepresent the tire pressure, such value is eliminated from the data for judging the tire pressure. When the value is calculated under a situation where any tire is slipping relative to a road surface, it is highly possible that the calculated value misrepresents the tire pressure. The situation where the tire slippage exists is found out by comparing a driving wheel acceleration with a driven wheel acceleration, and the value calculated under such situation is omitted from the data to be used for judging the tire pressure.

Abstract: The present invention provides a printed wiring board on which a bear chip is bonded in face-down. The printed wiring board has wiring patterns extending over the printed wiring board, wherein a plurality of wirings are provided which extend radially and outwardly from a center area of the printed wiring board, and wherein each of the wirings comprises at least a bear chip mounting pad region for contacting bumps of the bear chip, at least an external wiring pad region for connecting to an external wiring, and at least a covered region being covered by at least an insulation layer and the covered region separating between the bear chip mounting pad region and the external wiring pad region and a sealing material is filled within a space defined between the printed wiring board and the bear chip.

Abstract: A flux is applied to a circuit board on which solder is deposited beforehand. Then, the circuit board is subjected to reflow and then to rinsing. After the rinsing, an IC chip 1 having metal bumps on its electrodes, is mounted to the circuit board. Before the mounting, the chip 1 and circuit board are heated in an inactive gas atmosphere having a low oxygen concentration. At the time of mounting, the solder is melted at a temperature higher than its melting point so as to connect the chip 1 to the circuit board.

Abstract: A rotary position control device is provided with a three-rotary position controlling mechanism. The control device includes a disk member having a toothed portion on its circumferential part, to which an output shaft is secured in order to drive a driven source coupled to the output shaft. The disk member further has a circumferentially spaced slot having a recessed portion provided halfway between the both ends, the both ends and the recessed portion functioning as first, second and third stopper portions which receive a rod member disposed in the slot. The disk member stops its rotation when the rod member engages the both ends of the slot of the disk and also when the rod member engages the recessed portion, this third stop position of the disk member being achieved only when the electromagnetic solenoid is energized, thus causing the required relative movement between the output shaft and the driven source coupled to the output shaft.