Abstract: A scanning optical system capable of automatic focusing includes a gas laser 10 for emitting writing beam, a polygonal mirror 20 for deflecting and reflecting the rays of light from the gas laser 10, a scanning lens 40 that is telecentric with respect to an image plane 30 and which focuses the deflected rays of light to form an image on the image plane, a focus detector 50 that receives the reflected light from the image plane 30 to detect the state of focusing on the plane by the scanning lens 40, and a focus adjusting unit 60 that brings the scanning lens 40 into focus on the image plane 30 on the basis of the output of the focus detector 50. This optical system can be properly corrected for the image plane in such a way that it will not be out of the depth of focus on account of its waviness, tilting and other phenomena even if the F number of the system is reduced.

Abstract: The improved zoom lens system comprises, in order from the object side, a negative first lens group to maintain a constant focal position, a positive second lens group to control zooming, and a negative third lens group to operate as a relay lens unit. The third lens group moves towards the object during zooming from the wide-angle position to the middle-angle position and towards the image plane during zooming from the middle-angle position to the narrow-angle position. This three-group lens system is compact in overall size and can suppress the aberrational variations associated with zooming.

Abstract: A zoom lens system for use with a compact camera includes, in order from the object side, a first lens unit having a positive focal length, a second lens unit having a positive focal length and including a positive plastic lens, and a third lens unit having a negative focal length. When zooming is carried out from a wide-angle end to a narrow-angle end, the first, second and third lens units are all moved towards the object in such a manner that a distance between the first and second lens units increases whereas a distance between the second and third lens units decreases. Proper positioning of the positive plastic lens and meeting certain conditions improves the characteristics of the lens system.

Abstract: A process for producing a sintered apatite article having a porous surface by contacting a dense sintered apatite article with an acidic buffer solution, provided that the acidic buffer solution does not contain phosphoric acid.

Abstract: A surface reflector according to a first aspect has an oxide undercoat formed on a substrate, a reflecting aluminum layer formed over the oxide undercoat, and a protective layer formed over the reflecting layer. A surface reflector according to a second aspect has a chromium sulfide undercoat formed on a substrate, a reflecting silver layer formed over the chromium sulfide undercoat, and a protective layer formed over the reflecting layer. A surface reflector according to a third aspect has an oxide undercoat formed on a substrate, a sulfide undercoat formed over the oxide undercoat, a reflecting silver layer formed over the sulfide undercoat, and a protective layer formed over the reflecting layer.

Abstract: An attachment lens system for close-up photography in use with a master lens system in such a fashion that the attachment lens system is attached to the front of the master lens system, comprising a first lens as a positive component, a second lens whose face on the object side is convex, the second lens serving as a positive component, a third lens whose face on the master lens side is concave, the third lens serving as a negative component, and the first to third lenses being arranged in this order from the object to the master lens system, and the specific conditions on the working distance, a negative power of the lens system of the attachment lens system on the master lens system side, and the thicknesses of the specific lenses contained in the attachment lens system being satisfied.

Abstract: A surveying instrument comprising optical system means having an optical axis to be coincided with an object to be observed, positional deviation detecting means for detecting the deviation of said optical axis with respect to the object and either means for displaying the detection result of said positional deviation detecting means or means for driving said optical system according to the detection results of said positional deviation detecting means so as to bring said axis in coincidence with the object. According to the present invention, an observer can achieve surveying operation over watching the display, and thus easy and accurate operation is possible.

Abstract: Audio and/or video signals are recorded on coaxial tracks of a magnetic disk in an electronic still camera. Control circuitry is provided to implement playback from or erasure of a single track, all of the tracks, or a selected plurality of adjacent tracks In the latter case the R/W head is accessed to a predetermined "starting" track, whereafter the playback or erasing operation is performed on successive tracks radially inwardly or outwardly from the starting track until a predetermined "final" track is reached.

Abstract: A light beam emitted from a light source such as a semiconductor laser, is irradiated onto a recording section such as a photosensitive drum, through a scanning section composed of a rotary polygonal mirror. In a predetermined position in a plane formed by the scanning light beam, a columnar fluorescent optical fiber is arranged perpendicular to this plane, containing fluorescent substances therein. The fluorescent substances generate fluorescent light when the light beam is incident onto these fluorescent substances which is received by the photodetector arranged on the end face of the fluorescent optical fiber. As a result, even when a reflecting face of the rotary polygonal mirror is inclined irregularly, the light beam is incident to the fluorescent optical fiber so that it is not necessary to adjust the position of the fluorescent optical fiber.

Abstract: A finder apparatus for use with a lens-shutter type camera composing a zoom imaging optical system, a zoom finder optical system separate from said zoom imaging optical system, and an electronic flash device. The zoom finder optical system is made as a real-image zoom finder apparatus, with part of the associated optical elements being disposed behind the electronic flash device, and part of the optical path from the objective lens to the eyepiece being bent backward of the electronic flash device to pass through the optical element disposed behind the electronic flash device.

Abstract: Disclosed herein is an automatic focusing device high in focusing accuracy, in which an amount of drive for driving a focusing lens to a position focused on an object can be renewed during the focusing lens moving to the focused position. Further, the automatic focusing device is provided with a speed changing means capable of changing the movement speed of the focusing lens according to an amount of drive to the focused position.

Abstract: In an automatic sorting system for sorting objects conveyed on a conveyor, a camera is used for pattern recognition of the object being sorted. Due to the difference in sizes of the objects being sorted, the camera must be focused depending on the size of the object under consideration. Instead of moving the camera section itself, an optical path bending section can be included between the camera and the objects to be examined. The optical path bending section includes at least one pair of reflector mirrors disposed so that the reflecting surfaces thereof face each other at an angle of 90 degrees. In order to enable focusing for different sized objects, the optical path bending section can be moved in a direction parallel to the optical paths entering and exiting the optical path bending section.

Abstract: A composition for forming a calcium phosphate type setting material comprising(1) powder comprising at least one of .alpha.-tricalcium phosphate and tetracalcium phosphate; and(2) a setting solution comprising an aqueous acidic solution having dissolved therein at least one polysaccharide selected from the group consisting of carboxymethyl chitin, glycol chitin, pullalan, high methoxy-pectin and chitosan in such an amount that the setting solution has a viscosity of 70 cp or more, anda process for producing a calcium phosphate type setting material using such a composition.

Abstract: A combination of photographic film and electronic single-lens reflex camera. An electronic imaging and recording unit is detachably mounted on the single-lens reflex camera in place of the view finder and converts the image light into an electronic signal to be recorded on a magnetic disk. The exposure control for the electronic imaging is partially performed in the main camera body.

Abstract: A servo apparatus capable of detecting a signal which is approximately equal to a true velocity of a driven system. It is therefore possible to expand a servo pull-in-capable region without expanding a servo band, and to prevent an occurrence of cycle slipping occurring.

Abstract: A porous ceramic sinter and a process for producing the same are disclosed, which sinter has macropores with a pore size of from 20 to 2,000 .mu.m and three-dimensionally communicating pores that are made of interstices between secondary particles.

Abstract: A large aperture, medium telephoto lens system is disclosed which is composed of a front group G.sub.F that comprises, in order from the object side, at least two positive lens elements having a strong convex surface directed toward the object and a negative lens having a strong concave surface directed toward the image and which has a positive overall refractive power, and a rear group G.sub.R with a surface S.sub.R1 which is the closest to the object being convex toward the object and which the a positive overall refractive power, with only the rear group G.sub.R being moved along the optical axis to perform focusing operations.

Abstract: A column for liquid chromatography comprising particles of a calcium phosphate based compound packed in a column, wherein particles of a calcium phosphate based compound which are packed in the portion of said column where a solvent is to be injected have a durability higher than that of particles of a calcium phosphate compound which are packed in the remaining portion of said column.

Abstract: An optical system particularly for a laser beam printer comprising a semiconductor laser, a collimating lens, a cylindrical lens having curvature in the sub-scanning cross section, a deflector and anamorphic scanning lens system concentrating the light on a scanning plane. The anamorphic scanning lens system may have one to four lenses but has one lens with a convex toric surface facing the scanning plane. The anamorphic scanning lens system has stronger power in the sub-scanning cross section than in the main scanning cross section.