Abstract: An optical head is composed of an objective 2, a composite diffraction element 3 having six areas divided by three parting lines 3a to 3c; and a substrate 5 on which a light-emitting element and a plurality of light-receiving elements are arranged. A focus and a tracking error signals are generated based on signals from the light-receiving elements that receive those of a plurality of luminous fluxes divided by the composite diffraction element 3 which result from passage through the portion between the parting lines 3b and 3c. In generating the tracking error signal, signals from the light-receiving elements that receive luminous fluxes resulting from passage through the outside of the parting lines 3b and 3c are used to correct an offset in the tracking error signal caused by the movement of the objective.

Abstract: Copper fine powder has an electrical resistance in its powdery state of not more than 1×10−3&OHgr;.cm; a BET specific surface area ranging from 0.15 to 0.3 m2/g; a tap density of not less than 4.5 g/cc; a product of the tap density and the particle size, of not less than 13, the particle size being calculated from the specific surface area and a particle size distribution observed in the microtrack measurement as expressed in terms of D50 and D90 ranging from 4 to 7 &mgr;m and 9 to 11 &mgr;m, respectively; and a weight loss through hydrogen-reduction of not more than 0.30%. The copper fine powder is prepared by adding an alkali hydroxide to an aqueous copper salt solution containing divalent copper ions maintained at not less than 55° C. in an amount of not less than the chemical equivalent to form cupric oxide; then gradually adding a reducing sugar to the reaction system while maintaining the temperature of the system to not less than 55° C.

Abstract: A nickel fine powder includes 0.02 to 1.0% by weight of magnesium and/or 0.02 to 0.1% by weight of calcium dispersed in the nickel. A method for preparing the nickel fine powder includes the steps of forming nickel hydroxide by mixing an aqueous solution containing a magnesium salt and/or a calcium salt and a nickel salt with an aqueous solution of sodium hydroxide and then reducing the hydroxide with a hydrazine reducing agent. The nickel fine powder has thermal shrinkage characteristics very close to those observed for ceramic substrates and is accordingly suitable as a material for producing an internal electrode for laminated ceramic condensers.

Abstract: A method for preparing nickel fine powder is herein disclosed, which comprises the steps of mixing an aqueous sodium hydroxide solution comprising, on the basis of the total weight of the sodium hydroxide present in the aqueous solution, 75 to 85% by weight of liquid caustic soda as specified in JIS K 1203 and 25 to 15% by weight, in total, of at least one of sodium hydroxide as specified in JIS K 8576 and solid caustic soda as specified in JIS K 1202, with an aqueous solution of nickel sulfate to form nickel hydroxide, then reducing the resulting nickel hydroxide with hydrazine and recovering nickel fine powder produced. The nickel fine powder prepared by the method has an average particle size of the primary particles ranging from 0.1 to 0.9 .mu.m, a D.sub.90 value of not more than 2.1 .mu.m and a tap density of not less than 3.5 g/cc.

Abstract: Herein disclosed is 6 indium tin oxide (ITO) fine powder whose crystal form is a corundum type one and which has a true specific gravity of not less than 6.5 g/cc, a green density of not less than 3.0 g/cc, and a Seebeck coefficient of less than 30 .mu.V/cc at ordinary temperature and less than 80 .mu.V/cc after heating at 200.degree. C. The ITO fine powder can be prepared by a method which comprises the steps of neutralizing an aqueous solution containing an indium salt and a tin salt with ammonia to thus control the pH of the reaction solution to the range of from 6.8 to 7.5; separating the resulting neutralized precipitates through filtration; drying and washing the precipitates; calcining the precipitates in the air at a temperature ranging from 550 to 700.degree. C.; and then reducing-burning at a temperature ranging from 350 to 450.degree. C. in a reducing atmosphere.

Abstract: The electrically conductive, barium sulfate-containing composition consists of BaSO.sub.4 particles having a surface area of from 0.1 to 150 m.sup.2 /g. The BaSO.sub.4 particles each are provided with a SnO.sub.2 coating having a thickness of 2 to 80 nm and containing from 1 to 15% by weight of the Sb.sub.2 O.sub.3. The electrically conductive, barium sulfate-containing composition is made by a method including the steps of adding a first acidic solution containing 1 to 95% by weight SnCl.sub.4 and a basic solution to an aqueous dispersion from 50 to 800 g/l of BaSO.sub.4 to make a basic mixture having a pH from 9 to 15; then adding an acid to the basic mixture to form an acidic mixture having a pH from 4 to 1; then adding a second acid solution containing 0.5 to 60% by weight of SbCl.sub.

Abstract: A work cutting apparatus in which clearance adjustment is simultaneously possible for the two sides of the L-shape of the blade by a single adjustment operation and in which the elevation system of the movable blade has a simple arrangement. The work cutting apparatus is provided with a fixed blade of which the plan shape is approximately L-shaped, and a movable blade that moves vertically and comprises an approximate l-shape in alignment with the fixed blade. The movable blade is mounted on the tip of a ram that pivots vertically via a pivot support shaft arranged on the lower frame. The pivot support shaft is an eccentric shaft and, by adjusting the rotation of the angle of the shaft, the oscillation center of the ram is changed and the clearance adjustment of the blades is possible.

Abstract: A silver sol comprises silver particles having a particle size ranging from 1 to 100 nm and a silver solid content ranging from 1 to 80% by weight. The silver sol can be prepared by a method comprising the steps of reacting a solution of a silver compound with a reducing agent at a temperature ranging from 5 to 50.degree. C. and a stirring speed falling within the range of from 1,000 to 10,000 rpm to form silver fine particles; recovering the resulting silver fine particles using a centrifugal separator; and then dispersing the silver fine particles in a medium to give a silver sol having a silver solid content ranging from 1 to 80% by weight. The silver sol or a coating material obtained by diluting the sol to a desired silver solid content and, if desired, adding a binder permits the formation of a transparent conductive film on, for instance, a cathode-ray tube while reducing the production cost.

Abstract: A electrically-conductive barium sulfate filler and a method for preparing same are herein disclosed and it comprises a particulate core material composed of barium sulfate provided thereon with a coating film of tin dioxide which may be optionally doped with niobium or tentalum, the bare core material free of coating film having a specific surface area ranging from 0.1 to 150 m.sup.2 /g and the film having a thickness ranging from 2 to 80 nm.

Abstract: A magneto-optical pick-up for recording and reproducing information to an information recording medium comprises an optical module comprising an integral light emitting element and receptor element having plural light reception areas, and a diffraction grating on the light incident/emission plane, an objective lens, a polarizing prism provided integrally to the optical module in the light path between the light-emitting element and an objective lens and having the reflectivity and transmittance differing for P-polarized and S-polarized lights, and a polarizing element provided internally or integrally to the optical module which divides the light reflected by or passed through the polarizing prism into light having at least two mutually-perpendicular polarization components to guide the divided lights to the receptor element.

Abstract: An optical pick-up for use in optical disk devices comprises an objective lens having an outer ring formed therearound and a lens holder for positioning and holding the objective lens, the lens holder having first and second inner walls between which an annular shoulder portion is formed, and plural recesses formed on the annular shoulder portion as reservoirs into which excess adhesive agent is collected when adhesive agent is applied to a gap defined between the first inner wall and the outer ring of the objective lens. Various structures for collecting excess adhesive agent are also disclosed.

Abstract: Composite conductive powder comprises a calcined mixture of conductive powder mainly comprising indium oxide which contains at least one member selected from the group consisting of tin oxide, titanium oxide and zirconium oxide as a dopant and conductive powder mainly comprising tin oxide which contains at least one member selected from the group consisting of antimony oxide, tantalum oxide and niobium oxide as a dopant, and a conductive film is formed from the composite, conductive powder. The composite, conductive powder and the conductive film produced from the powder permit the reduction in the amounts of materials for the ITO film, in particular, indium which is an expensive material and the composite, conductive powder can simultaneously satisfy both requirements for high transparency and high conductivity even if it is used for the formation of films through the coating technique.

Abstract: A resist composition for forming a pattern, which comprises (a) a compound represented by the following formula (1) and satisfying the following inequalities, ##STR1## wherein R.sup.1 is hydrogen atom or methyl group, R.sup.2 is a monovalent organic group, m is 0 or a positive integer, n is a positive integer, and m and n satisfying a condition of 0.03.ltoreq.n/(m+n).ltoreq.1, (b) a compound capable of generating an acid when irradiated with light, and (c) 4-phenylpyridine, wherein a weight-average molecular weight, Mw and a number-average molecular weight, Mn satisfy the following inequality, 4,000.ltoreq.Mw.ltoreq.50,000, 1.10.ltoreq.Mw/Mn.ltoreq.2.50 (Mw and Mn respectively represent value converted in styrene).

Abstract: A electrically-conductive barium sulfate filler and a method for preparing same are herein disclosed and it comprises a particulate core material composed of barium sulfate provided thereon with a coating film of tin dioxide which may be optionally doped with niobium or tentalum, the bare core material free of coating film having a specific surface area ranging from 0.1 to 150 m.sup.2 /g and the film having a thickness ranging from 2 to 80 nm.

Abstract: A resist composition for forming a pattern, which comprises (a) a compound represented by the following formula (1) and satisfying the following inequalities, ##STR1## wherein R.sup.1 is hydrogen atom or methyl group, R.sup.2 is a monovalent organic group, m is 0 or a positive integer, n is a positive integer, and m and n satisfying a condition of 0.03.ltoreq.n/(m+n).ltoreq.1, (b) a compound capable of generating an acid when irradiated with light, and (c) a nitrogen-containing compound, wherein a weight-average molecular weight, Mw and a number-average molecular weight, Mn satisfy the following inequality, 4,000.ltoreq.Mw.ltoreq.50,000, 1.10.ltoreq.Mw/Mn.ltoreq.2.50 (Mw and Mn respectively represent value converted in styrene).

Abstract: In an optical head, a light emitting element emits an optical beam, and the beam is condensed by a condensing element onto an information recording medium. A first plate beam-splitting element has a splitting ratio of P polarization to S polarization, and it splits at least a part of the beam reflected by the information recording medium along a direction different from that of a direction returning to the light emitting element. A second plate beam-splitting element is provided in parallel to the first plate beam-splitting element, and it splits the beam split by the first plate beam-splitting element into at least two beams having polarization planes perpendicular to each other. The two beams are detected by a pair of photosensors.

Abstract: A fibrous electrically-conductive filler herein provided comprises fibrous aluminum borate as a core material provided thereon with, in order, an optional titanium oxide intermediate layer and an antimony-free tin oxide layer. The fibrous electrically-conductive filler can be prepared by a method which comprises the steps of optionally forming an intermediate layer of titanium oxide by depositing titanium oxide hydrate on the surface of the core material and then calcining the titanium oxide hydrate layer; then forming a coating layer of tin oxide hydrate on the surface of the titanium oxide-coated fibrous aluminum borate or the fibrous aluminum borate as a core material and then calcining the coating layer at a temperature ranging from 150.degree. to 600.degree. C. in an inert gas atmosphere or a reducing atmosphere to form an antimony-free tin oxide layer.

Abstract: A method for preparing electrically-conductive zinc oxide is herein disclosed, which comprises the steps of preparing a vapor mixture comprising zinc vapor and vapor of at least one member selected from the group consisting of dopant-forming metal compounds having boiling points of not more than that of zinc and free of oxygen atom in a predetermined mixing rate ranging from 0.005 to 5 parts by weight of the dopant-forming metal, as expressed in terms of the oxide thereof, per 100 parts by weight of zinc, as expressed in terms of zinc oxide; then oxidizing the vapor mixture with an oxidizing gas.

Abstract: A fibrous electrically-conductive filler herein provided comprises fibrous aluminum borate as a core material provided thereon with, in order, an optional titanium oxide intermediate layer and an antimony-free tin oxide layer. The fibrous electrically-conductive filler can be prepared by a method which comprises the steps of optionally forming an intermediate layer of titanium oxide by depositing titanium oxide hydrate on the surface of the core material and then calcining the titanium oxide hydrate layer; then forming a coating layer of tin oxide hydrate on the surface of the titanium oxide-coated fibrous aluminum borate or the fibrous aluminum borate as a core material and then calcining the coating layer at a temperature ranging from 150.degree. to 600.degree. C. in an inert gas atmosphere or a reducing atmosphere to form an antimony-free tin oxide layer.

Abstract: A lens drive mechanism for an optical disc player includes a movable unit including an objective lens for focusing a coherent beam of light on an optical disc, a lens holder carrying the objective lens, focusing and tracking coils secured to opposite portions of a periphery of the lens holder. The lens drive mechanism also includes permanent magnets and yokes, and a plurality of support members connected at one end to the periphery of the lens holder and at the opposite end to a support fixture for supporting the movable unit for movement in focusing and tracking directions substantially perpendicular to each other.