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.

Abstract: A valve driving device for an internal combustion engine including a hydraulic lifter in each rocker arm and a rocker shaft swingably supporting the rocker arms wherein a first oil passage is provided through the internal bore of the rocker shaft for supplying oil to a reservoir of the hydraulic lifter. A second oil passage is formed through a rocker support for supplying oil in the first oil passage, and an air exhaust port is provided for exhausting air intruded into the internal bore of the rocker shaft to outside.

Abstract: A hydraulic lifter incorporated into a rocker arm of a valve train in an internal combustion engine includes a cylinder formed in the rocker arm, a plunger arranged slidably in the cylinder, a valve seat member dividing an inside portion of the cylinder into a pressure chamber and a reservoir chamber for working fluid, a check valve allowing the working fluid to flow from the reservoir chamber into the pressure chamber, a spring positioned within the pressure chamber to bias the plunger, and a passage for supplying the working fluid to the reservoir chamber.

Abstract: A valve actuating device for an internal combustion engine having a cam and a valve stem comprises a rocker arm receiving a load from the cam at one end and actuating the valve stem at the other end thereof, a hydraulic valve lifter slidably disposed in the rocker arm, a hollow rocker arm shaft pivotally supporting the rocker arm, a first fluid supply passage formed in the rocker arm shaft, a second fluid supply passage formed in the rocker arm, and an air hole formed in an upper portion of the hollow rocker arm shaft.

Abstract: The hydraulic lifter system for variable cylinder engines comprises a hydraulic lifter which is operatively connected to a rocker arm and which includes a body having a pressure chamber and a reservoir chamber, a plunger slidably positioned within the body, and a check valve to allow the fluid flow only into the pressure chamber from the reservoir chamber, a solenoid valve positioned by the side of the hydraulic lifter, means for causing the check valve to open to thereby establish the fluid communication between the pressure and reservoir chambers by means of the solenoid valve, and a stopper member for locking the plunger to stop the operation of the hydraulic lifter in association with the means for causing the check valve to urge to open.