Abstract: A printed wiring board comprising an insulating film, a wiring pattern formed on at least one surface of the insulating film, a metal plating layer on the wiring pattern, and a resin protective layer provided on the wiring pattern with the metal plating layer in between so as to expose terminal portions of the wiring pattern plated with the metal, wherein the metal plating layer on the wiring pattern has a surface roughness (Rz) of 1.1 ?m or above. A semiconductor device includes the printed wiring board and an electronic component mounted thereon. In production of the printed wiring board, the wiring pattern is surface roughened prior to forming the metal plating layer such that the metal plating layer formed thereon will have a surface roughness (Rz) of 1.1 ?m or above.

Abstract: A printed wiring board comprising an insulating film, a wiring pattern formed on at least one surface of the insulating film, a metal plating layer on the wiring pattern, and a resin protective layer provided on the wiring pattern with the metal plating layer in between so as to expose terminal portions of the wiring pattern plated with the metal, wherein the metal plating layer on the wiring pattern has a surface roughness (Rz) of 1.1 ?m or above. A semiconductor device includes the printed wiring board and an electronic component mounted thereon. In production of the printed wiring board, the wiring pattern is surface roughened prior to forming the metal plating layer such that the metal plating layer formed thereon will have a surface roughness (Rz) of 1.1 ?m or above. The surface roughening treatment of the wiring pattern reduces problems such as foaming in the resin protective layer by thermal shock even when the metal plating layer is made of a low-activity metal such as gold.

Abstract: A laminate film for mounting electronic devices includes a conductive layer and an insulating film which are bonded through thermocompression bonding. The coefficient of thermal expansion of the insulating film along the width direction thereof is substantially equal to or higher than that of the conductive layer along the width direction thereof.

Abstract: The object of the classifier of the present invention is to reduce the classification point for classifying powder. The classifier includes a classifying cover having a conical bottom surface, a classifying plate provided under the classifying cover and having a conical top surface opposite the conical bottom surface of the classifying cover, and a plurality of louvers provided annularly around a classifying chamber defined between the conical bottom surface and the conical top surface to define passages for secondary air therebween. The conical bottom surface is inclined at a larger angle than the conical top surface.

Abstract: A surface acoustic wave convolver includes first and second interdigital electrodes for exciting surface acoustic waves and an output electrode for detecting the surface acoustic waves to extract a convolution output as an electrical signal, the first and second interdigital electrodes and the output electrode being formed on a piezoelectric or electrostrictive substrate.

Abstract: A multifilament type plastic optical fiber having a substantially rectangular cross-section and an islands-in-the-sea structure in which 100 to 10,000 islands are arranged in the sea, wherein the respective islands have a substantially circular cross-section and a core-sheath structure, the islands are arranged in a zigzag-stacked structure, the core occupaney ratio in the multifilament type optical fiber cores section is at least 50% and the brightness index value I which is defined by the following (1), is at least 4.5.times.10.sup.-2 : ##EQU1## wherein S stands for the core occupancy ratio in the multifilament type optical fiber, .alpha. stands for the transmission loss (dB/m) per meter of the multifilament type optical fiber, NA stands for the numeral apertures, and L stands for the length (m) of the used optical fiber.

Abstract: An endoscope comprising as an image-transmitting member a multifilament type plastic optical fiber, an object lens arranged on one end of the optical fiber and a device for guiding an image of an object transmitted to the other end of the optical fiber to an image-receiving portion, wherein the multifilament type plastic optical fiber has an islands-in-sea structure in which 50 to 10,000 light-transmitting core-sheath structure islands having a diameter of 5 to 200 .mu. are arranged in the sea so that the same positional relationship of the islands is maintained on both ends of the optical fiber, and the core occupancy ratio in the total cross-section of the optical fiber is at least 50%.

Abstract: An impact tool for striking a tool such as a chisel includes a piston mounted in a cylinder. Upper, middle and lower chambers are formed therebetween. Pressure oil is fed into and discharged from the middle and lower chambers to reciprocate the piston in the cylinder under oil pressure. During a downward stroke of the piston, the oil pressure in the lower chamber is kept low. But just before it strikes a tool, the oil pressure in the lower chamber is adapted to increase so as to prevent what is called cavitation or prevent air bubbles mixed in the pressure oil in the lower chamber from growing suddenly owing to a sharp drop in the oil pressure which is caused by the rebound of the piston after striking the tool.

Abstract: A multifilament type plastic optical fiber having a substantially rectangular cross-section and an islands-in-the-sea structure in which 100 to 10,000 islands are arranged in the sea, wherein the respective islands have a substantially circular cross-section and a core-sheath structure, the islands are arranged in a sigzag-stacked structure, the core occupancy ratio in the multifilament type optical fiber cores section is at least 50% and the brightness index value I which is defined by the following (1), is at least 4.5.times.10.sup.-2 :I=S.multidot.NA.sup.2 .multidot.10.sup.-(.alpha.L/10) (1)wherein S stands for the core occupancy ratio in the multifilament type optical fiber, .alpha. stands for the transmission loss (db/m) per meter of the multifilament type optical fiber, NA stands for the numeral apertures, and L stands for the length (m) of the used optical fiber.

Abstract: An optical fiber array comprising a great number of multifilament type plastic optical fibers having a substantially rectangular peripheral sectional shape and including 10 to 10000 light-transmitting islands having a diameter of 5 to 200 .mu.m, which are densely arranged in the sea, wherein one ends of the multifilament type plastic optical fibers are arranged in one line or a plurality of lines and the other ends thereof are integrated in a substantially rectangular or substantially circular shape.

Abstract: A plastic optical fiber which is superior in the light transmission characteristics, particularly in those within a visible light region and also superior in heat resistance, and a process for producing the same are provided, which plastic optical fiber comprises a polycarbonate as its core material and a polymer as its cladding material having a refractive index lower than that of the core material, wherein the relationship between the light transmission loss L.sub.500 (dB/km) of the fiber as measured at a wavelength of 500 nm and that as measured at 660 nm being expressed by the following inequality:L.sub.500 <L.sub.660 +4,000.

Abstract: A multifilament type plastic optical fiber having a substantially uniform cross-section and an islands-in-sea structure, in which 10 to 10,000 islands are arranged in the sea, the respective islands have a substantially uniform cross-section having a diameter of 10 to 200.mu.

Abstract: There is provided a plastic optical fiber capable of exhibiting good light transmitting characteristics even at high temperatures, which comprises a core layer, a cladding layer, and a protective layer as basic consititutional units, wherein the protective layer has a heat distortion temperature [HDT] of at least 120.degree. C., a thickness of at least 10 .mu.m, and a cross-sectional area of at least 0.07 times the sum of cross-sectional areas of the core and cladding layers. There is also provided such a plastic optical fiber good in high-temperature light transmitting characteristics, which comprises a core layer, a cladding layer, and a protective layer as basic constitutional units and has a plastic coating layer having a silane-crosslinked structure provided as an outer layer thereof, wherein the protective layer has a heat distortion temperature [HDT] of at least 120.degree. C., a thickness of at least 10 .mu.m, and a cross-sectional area of at least 0.

Abstract: A pneumatic impact wrench. This device is characterized in the improvement of the torque controlling mechanism incorporated therein, said mechanism comprising a torsion bar, a spindle case, a fluid element, and valves, holes and passages all functioning in close linkage with each other thereby enabling execution of the torque control and even change of the torque control value precisely. In this mechanism, an air motor driving this device is brought to a halt automatically as the result of closing of a main valve in relation to the operation of said fluid element, said operation of said fluid element being available from air pressure change caused by the closing or narrowing of an air exhausting hole taking place in compliance with twisting of said torsion bar under its partially rolling effect at the rear portion thereof, said torsion bar fixing to said spindle case at their forward portions at this time being imparted with a rotation-suspending resistance thereto at their fixing portion.