Abstract: A variable magnification optical system comprising a first lens group, a second lens group, a third lens group, and a rear group in order from object side is configured so that at varying magnification the distances between adjacent lens groups are varied; at a predetermined object distance the variable magnification optical system has focused states with different amounts of aberration; the rear group includes a first focusing lens group and a second focusing lens group disposed closer to an image side than the first focusing lens group, the first and second focusing lens groups moving along different trajectories at focusing; at the object distance the first and second focusing lens groups move at transition from a first focused state to a second focused state; and the following conditional expression is satisfied: ?6.80<f1/f2<?0.05 where f1 and f2 are the focal lengths of the first and second lens groups, respectively.

Abstract: A variable magnification optical system including a plurality of lens groups, which is six or more lens groups and comprises a first lens group having positive refractive power and a rear group disposed closer to an image side than the first lens group, is configured so that at varying magnification the distances between the lens groups are varied, the first lens group consists of two or fewer lenses, and both the following conditional expressions are satisfied: 8 . 0 ? 0 < f ? 1 / D ? 1 < 2 ? 7 .00 1. < M ? 1 / D ? 1 < 1 ? 2 . 0 ? 0 where f1 is the focal length of the first lens group, D1 is the thickness of the first lens group on an optical axis, and M1 is the amount of movement of the first lens group at varying magnification from a wide-angle end state to a telephoto end state.

Abstract: A variable magnification optical system including a plurality of lens groups, which is six or more lens groups and comprises a first lens group having positive refractive power and a rear group disposed closer to an image side than the first lens group, is configured so that at varying magnification the distances between the lens groups are varied, the first lens group consists of two or fewer lenses, and both the following conditional expressions are satisfied: 7.50<f1/D1<55.00??(1) 4.00<M1/D1<22.00??(2) where f1 is the focal length of the first lens group, D1 is the thickness of the first lens group on an optical axis, and M1 is the amount of movement of the first lens group at varying magnification from a wide-angle end state to a telephoto end state.

Abstract: A mask blank comprises a substrate with a multilayer reflective film and a pattern-forming thin film formed on a main surface of the substrate in this order. The thin film contains tantalum, molybdenum, and nitrogen. In the thin film, a ratio of a nitrogen content [atomic %] to a total content [atomic %] of tantalum and molybdenum is 0.15 or more.

Abstract: An imaging optical system of the far pupil type, which is applicable to an exposure apparatus, is provided with six reflecting mirrors and forms an image of a first plane on a second plane. An incident pupil of the imaging optical system is positioned on a side opposite to the imaging optical system with the first plane intervening therebetween. A condition of ?14.3<(PD/TT)/R?8.3 is fulfilled by a distance PD which is provided along an optical axis between the incident pupil and the first plane, a distance TT which is provided along the optical axis between the first plane and the second plane, and an angle of incidence R (rad) of a main light beam which comes into the first plane.

Abstract: An aperture diaphragm plate is provided to define a light flux on a pupil plane of an optical system or a plane or surface disposed in the vicinity of the pupil plane. An aperture, which is formed in the aperture diaphragm plate, has a three-dimensional shape corresponding to an optimum pupil shape of the optical system. It is possible to improve the imaging characteristic brought about by the optical system by providing the optimum pupil shape of the optical system.

Abstract: An imaging optical system of the far pupil type, which is applicable to an exposure apparatus, is provided with six reflecting mirrors and forms an image of a first plane on a second plane. An incident pupil of the imaging optical system is positioned on a side opposite to the imaging optical system with the first plane intervening therebetween. A condition of ?14.3<(PD/TT)/R<?8.3 is fulfilled by a distance PD which is provided along an optical axis between the incident pupil and the first plane, a distance TT which is provided along the optical axis between the first plane and the second plane, and an angle of incidence R (rad) of a main light beam which comes into the first plane.

Abstract: A method of manufacturing a ceramic molded product includes adding a binder mainly comprising a saccharide and water to a powder of ceramics such as silicon carbide and stirring the same to form an aqueous sludge having a fluidity, casting the sludge into an elastic die, molding the sludge while applying vibrations in a negative pressure state, solidifying the sludge by putting the die in which the sludge is cast to a temperature below freezing point for freeze-drying, and to a temperature where the binder is not frozen completely, then thawing the sludge in the negative pressure state and subliming and evaporating the water content in the binder, taking the molded product solidified in the die out of the die, further dewatering the demolded product by elevating the temperature to a temperature where the saccharide in the binder is dissolved, and then sintering the molded product.

Abstract: An aperture diaphragm plate is provided to define a light flux on a pupil plane of an optical system or a plane or surface disposed in the vicinity of the pupil plane. An aperture, which is formed in the aperture diaphragm plate, has a three-dimensional shape corresponding to an optimum pupil shape of the optical system. It is possible to improve the imaging characteristic brought about by the optical system by providing the optimum pupil shape of the optical system.

Abstract: A reflective projection optical system comprises a first optical unit having at least one reflecting optical element, and a second optical unit having at least one reflecting optical element. A focal point on the second surface side of the first optical unit approximately agrees with a focal point on the first surface side of the second optical unit. An angle between a normal to the first surface and a principal ray of the illumination beam incident to the first surface is larger than a value of arcsine of a numerical aperture on the first surface side of the reflective projection optical system. All the optical elements in the projection optical system are located outside an extension surface of a ray group defining an outer edge of the illumination beam incident to the first surface.

Abstract: A method of manufacturing a ceramic molded product includes adding a binder mainly comprising a saccharide and water to a powder of ceramics such as silicon carbide and stirring the same to form an aqueous sludge having a fluidity, casting the sludge into an elastic die, molding the sludge while applying vibrations in a negative pressure state, solidifying the sludge by putting the die in which the sludge is cast to a temperature below freezing point for freeze-drying, and to a temperature where the binder is not frozen completely, then thawing the sludge in the negative pressure state and subliming and evaporating the water content in the binder, taking the molded product solidified in the die out of the die, further dewatering the demolded product by elevating the temperature to a temperature where the saccharide in the binder is dissolved, and then sintering the molded product.

Abstract: There is provided a controlling apparatus for a disk data reading unit, comprises control board connected to the disk data reading unit which holds and rotates a disk storing a predetermined information and reads the predetermined information by properly moving an actuator on the disk, and controlling an operation of the disk data reading unit with forming a servo loop, and identifying section receiving a predetermined signal from the disk data reading unit so as to identify a type of the disk data reading unit.

Abstract: The present invention relates to a disc reproducing apparatus for allowing a tray that holds a disc to be unloaded and loaded from and in a cabinet. In the disc reproducing apparatus, a motor mount that holds a disc motor and a turn table can be transferred between the tray and a chassis in the cabinet. The tray has a pair of cavity portions functioning as a portion for holding a motor mount. The chassis has a pair of protrusion portions of guide shafts, a pair of lock levers, and a pair of guide protrusions as a portion for holding the motor mount. The lock levers are used as a means for transferring the motor mount between the tray and the chassis.

Abstract: High purity silicon carbide parts for a heat treating apparatuses for semiconductors; composed mainly of .alpha.-type silicon carbide and silicon; characterized in that a particle sizes of the .alpha.-type silicon carbide crystals composing the high purity silicon carbide parts are not larger than 44 .mu.m; a weight mean particle size of the .alpha.-type silicon carbide crystals is in a range from 2 to 25 .mu.m; high purity silicon is filled up among the particles of the .alpha.-type silicon carbide crystals; and a content of iron as an impurity element contained in the high purity silicon carbide parts is not larger than 5 ppm.

Abstract: A heat exchanger includes a cylindrical main body formed by extrusion molding having a first connection with a first inlet for cooling water and a first outlet for high temperature fluid and connected to one end of the main body and a second connection with a second inlet for the high temperature fluid and a second outlet for the cooling water. A cooling water passage is provided in the cylindrical main body and extends axially thereof. The cooling water passage is connected to the first inlet and the second outlet for the cooling water. The heat exchanger also includes a high temperature fluid passage in the main body extending along with the cooling water passage. The high temperature fluid passage is connected to the first outlet and the second inlet for the high temperature fluid and fins are connected to the high temperature fluid passage for heat exchanging.

Abstract: An optical disc player for playing optical discs includes a disc compartment for accommodating an optical disc, a disc holding mechanism for holding an optical disc accommodated in the disc compartment, a disc rotation drive mechanism for rotating the optical disc held by the disc holding mechanism, an optical pickup device which is radially movable in respect to the optical disc rotated by the disc rotation drive mechanism for optically tracing the optical disc and a pickup locking mechanism which is responsive to the disc holding mechanism for locking the optical pickup device during a non-operation of the tracing operation.

Abstract: An optical disc player for playing optical discs includes a disc compartment for accomodating an optical disc, a disc holding mechanism for holding an optical disc accomodated in the disc compartment, a disc rotation drive mechanism for rotating the optical disc held by the disc holding mechanism, an optical pickup device which is radially movable in respect to the optical disc rotated by the disc rotation drive mechanism for optically tracing the optical disc and a pickup locking mechanism which is responsive to the disc holding mechanism for locking the optical pickup device during a non-operation of the tracing operation.

Abstract: An optical disc player for playing optical discs includes a disc compartment for accommodating an optical disc, a disc holding mechanism for holding an optical disc accommodated in the disc compartment, a disc rotation drive mechanism for rotating the optical disc held by the disc holding mechanism, an optical pickup device which is radially movable in respect to the optical disc rotated by the disc rotation drive mechanism for optically tracing the optical disc and a pickup locking mechanism which is responsive to the disc holding mechanism for locking the optical pickup device during a non-operation of the tracing operation.

Abstract: A motor of a motor drive mechanism is driven by a logic control circuit and a motor driving circuit when an operating member for tape feed is operated. A shift control mechanism receiving a forward or reverse rotatory force from the motor controls a pinch roller included in a tape drive mechanism for a specified condition by means of a playback slider, and also controls a head to a predetermined position by means of a head slider. Thus, the motor drive mechanism can establish a forward or reverse tape feed mode in a tape recorder.

Abstract: A hydraulic valve lifter is mounted in a rocker arm of a valve train assembly of internal combustion engines. The lifter includes a cylinder formed in the rocker arm, a plunger reciprocably mounted in the cylinder, a seat member securely pressed in the cylinder above the plunger and provided with an outer circumferential portion extending in a direction of the plunger, a stopper surface formed at an end surface of the outer circumferential portion for restricting an axial movement of the plunger in a direction of the seat member, and a relief recessed area formed above the stopper surface for finishing machining process of the cylinder.