Abstract: In a focusing state determining device for determining a focusing state of a taking lens, an object light entering the taking lens is captured by focusing state determination imaging elements provided separately from a video imaging element, and the focusing state is determined according to luminance signals outputted from the focusing state determination imaging elements. Any error of determination of the focusing state induced by saturation of the luminance signals in imaging an object of high luminance is prevented by adjusting the gains of the image signals outputted from the focusing state determination imaging elements or the charge accumulation times of the focusing state determination imaging elements. High-frequency components are determined from the luminance signals obtained from the focusing state determination imaging elements (A, B, C), and the focus evaluation value is determined by integration thereof.

Abstract: A beam splitter (24)for splitting light in a wavelength range of about 500 nm to about 600 nm is arranged in a relay optical system of a taking lens (12). A green light beam reflected from the beam splitter (24) is directed through a relay lens (R3) to a focusing state determination imaging unit (26). The imaging unit (26) comprises three imaging elements (A, B, C) for capturing the directed green light beam to determine the focusing state. Thus, a device for determining the focusing state of the taking lens is provided, in which the green light beam is separated as an object light for determining the focusing state from the object light entering the taking lens (12), so that the focusing state can be determined with high accuracy on the basis of the high-frequency components of the image signal generated by capturing the green light beam by means of the imaging elements (A, B, C) having different optical path lengths.

Abstract: A beam splitter (24) for splitting light in a wavelength range of about 500 nm to about 600 nm is arranged in a relay optical system of a taking lens (12). A green light beam reflected from the beam splitter (24) is directed through a relay lens (R3) to a focusing state determination imaging unit (26). The imaging unit (26) comprises three imaging elements (A, B, C) for capturing the directed green light beam to determine the focusing state. Thus, a device for determining the focusing state of the taking lens is provided, in which the green light beam is separated as an object light for determining the focusing state from the object light entering the taking lens (12), so that the focusing state can be determined with high accuracy on the basis of the high-frequency components of the image signal generated by capturing the green light beam by means of the imaging elements (A, B, C) having different optical path lengths.

Abstract: In a focusing state determining device for determining a focusing state of a taking lens, an object light entering the taking lens is captured by focusing state determination imaging elements provided separately from a video imaging element, and the focusing state is determined according to luminance signals outputted from the focusing state determination imaging elements. Any error of determination of the focusing state induced by saturation of the luminance signals in imaging an object of high luminance is prevented by adjusting the gains of the image signals outputted from the focusing state determination imaging elements or the charge accumulation times of the focusing state determination imaging elements. High-frequency components are determined from the luminance signals obtained from the focusing state determination imaging elements (A, B, C), and the focus evaluation value is determined by integration thereof.

Abstract: A mixture of titanium dioxide and an oxide or carbonate of barium includes one or more transition metal elements selected from the group of V, Cr, Mn, Fe, Co, Ni and Cu, in the amount of 2 ppm or more. This mixture is used as a starting material. The mixture is heated to a predetermined temperature to make a melt. Then, a seed crystal of BaTiO.sub.3 is brought into contact with the melt under an environment with a low oxygen partial pressure of 0.02 atm. or less. From this state, the above melt is slowly cooled to grow a single crystal on the seed crystal. The thus obtained single crystal is heated in a temperature of 600 .degree. C. or more, under an oxidizing environment with its oxygen partial pressure more than 0.1 atm.

Abstract: A copper alloy wire has a composition composed of no less than 0.01% by weight of Ag and balance Cu and unavoidable impurities. The copper alloy wire has been prepared by drawing a wire stock having the composition at a reduction ratio of no lower than 40% and subjecting the wire stock to heat treatment for half annealing to have a tensile strength of no lower than 27 kg.multidot.f/mm.sup.2 and an elongateion of 5%. An insulated elecric wire includes the copper alloy wire as a conductor and an insulation layer covering the wire. Also, a multiple core parallel bonded wire includes two or more such insulated electric wires bonded parallel to each other.

Abstract: First, a steel wire is continuously dipped in molten copper or molten copper alloy so that copper or copper alloy builds up and solidifies on the peripheral surface of said steel wire, thereby obtaining an initial copper-clad steel wire. Then, the initial copper-clad steel wire is subjected to a first cycle of hot rolling by a caliber roll. The hot-rolled wire is dipped in molten copper or molten copper-alloy at least once so that copper or copper alloy builds up and solidifies thereon, thereby obtaining a final copper-clad steel wire.The final copper-clad steel wire is hot-rolled at a temperature of 750.degree. to 850.degree. C. and with a rolling ratio of 10 to 40%. Then, the hot-rolled wire is cold-rolled with a reduction of area of 20% or more.Thus, 75 to 95% of the cross sectional area of the obtained copper-clad steel trolley wire is occupied by the copper or copper alloy covering layer so that the electric conductivity of the trolley wire is as high as 80% IACS or more.

Abstract: A dip forming apparatus for continuously forming a cast rod includes a furnace for holding molten metal, and a crucible having an open top and a bottom wall. The crucible has a core wire-passing region vertically extending therethrough. The crucible has a hole formed through the bottom wall. A passage connects the furnaces to the core wire-passing region. A device is provided for keeping the molten metal in the furnace at a predetermined level so as to flow the molten metal from the furnace to the core wire-passing region through the passage. A partition wall is disposed in the passage and has a throttling orifice of a predetermined size formed therethrough so as to allow the molten metal to pass therethrough to limit the flow of the molten metal from the furnace to the core wire-passing region.

Abstract: There is disclosed a bushing for use in an apparatus for continuously passing a core wire through a crucible holding molten metal to accrete the molten metal on the core wire to form a cast rod. The bushing is connected to the crucible for passing the core wire therethrough into the crucible. The bushing is tubular and has an engaging portion for engaging with the core wire passing therethrough. The engaging portion is made of ceramics material containing a major proportion of at least one selected from the group consisting of zirconia, silicon carbide and silicon nitride.

Abstract: An electrode wire for wire electric discharge machining a workpiece at high speed and high accuracy and a process for preparing the same are provided. The electrode wire comprises a core wire made of a copper clad steel wire, 10 to 70% of the sectional area of the copper clad steel wire being occupied by copper, and a copper-zinc alloy layer covering the core wire. The copper-zinc alloy layer is prepared by coating the core wire with zinc by electroplating or hot galvanizing, followed by heating to disperse copper in the zinc layer to convert the same into a copper-zinc alloy layer wherein the concentration of zinc is increased gradually along the radially outward direction. The preferable thickness of the copper-zinc alloy layer ranges from 0.1 to 15 microns and the average concentration of zinc in the copper-zinc alloy layer is preferably less than 50% by weight but not less than 10% by weight.