Abstract: A projection lens for projecting images displayed on an image display device having angle-of-view dependency has high image focusing characteristics corresponding to high definition images, wide field angle, and telecentric characteristics. In addition, a projection television system using the same can be minimized in its size.

Abstract: A lens controls the chromatic aberration of an objective lens for practical use in an optical disk system. The lens has first and second aspherical surfaces each providing a positive refractive power for focusing a light through a transparent plate and satisfies a condition: ##EQU1## where f.sub.L =focal length of the lens, d.sub.c =thickness of the transparent plate, n.sub.c =refractive index of the transparent plate, .lambda.=center wavelength of the light, NA=numerical apperture of the lens, .nu..sub.L =local dispersion of the lens, and .nu..sub.c =local dispersion of the transparent plate. The local dispersion of each element is expressed by: ##EQU2## where n.sub.80 is refractive index at a center wavelength .lambda. nm, n.sub..lambda. +5 a refractive index at .lambda.+5 nm, and n.sub..lambda. -5 a refractive index at .lambda.-5 nm.

Abstract: A single lens having first and second aspherical surfaces each having a positive power is usable for, an objective lens of an optical pickup for an optical recording medium. The lens satisfies the following conditions:0.1<.vertline.m.vertline.<0.50.9<(d/f)<1.2where m denotes magnification; d denotes thickness of the lens; and f denotes focal length of the lens.

Abstract: A selective shading device has a number of shading plates or planar members and a supporting body that holds the plates or planar members in such a manner that they are arrranged radially with respect to an optical axis. The device blocks sagittal bundles of rays. A preferred example of the supporting body is a cylindrical frame that holds the shading plates perpendicularly to the inner surface thereof. Alternatively, the shading planar members are formed within a lens element along the edge thereof.

Abstract: A high definition projection lens for projecting on a screen an enlargement of an image appearing on a high resolution CRT is disclosed. The projection lens comprises a first lens having a positive optical power and a convex surface facing the screen, a meniscus second lens having a positive optical power, a third lens having bi-concave surfaces and a negative optical power, a fourth lens having a positive optical power, a fifth lens having bi-convex surfaces and a positive optical power, and a sixth lens having a negative power and an aspheric concave surface facing the fifth lens.

Abstract: A projection lens for projecting an image appearing on a cathode-ray tube onto a screen, small in residual aberrations, having a high imaging performance, also having a large aperture ratio and a wide field angle, suitable for a video projector having a high definition of, say, 1,125 scanning lines. The projection lens has, successively from the screen side, a Gauss type lens system, a positive lens mainly for enlarging the aperture ratio, and a negative lens mainly for widening the field angle, which negative lens has a strongly concave surface at the screen end.

Abstract: A method for producing a semiconductor laser of InGaAsP/InP type having a structure, in which an active layer isolated from outside is embedded in a groove in a substrate wafer, which comprises steps of: forming the groove in the substrate having a crystallographic plane of (100), on the upper surface of which a current blocking layer has been formed, along the <011> direction of the substrate, in a manner to be terminated at both sides of substrate wafer in the vicinity of the end faces of a laser resonator; and, thereafter, sequentially forming on the groove and other regions of the substrate clad layers and the active layer.

Abstract: An arrangement serves to swirl air flow into an engine to an adjustable degree. The degree of swirl in the air flow affects the duration of combustion of a mixture of air and fuel in the engine. The degree of swirl is adjusted so as to hold the duration of mixture combustion within an acceptable range, the acceptable range varying in accordance with engine operating conditions.

Abstract: A color corrected projection lens with a large aperture ratio and a wide angle of view for producing on a screen an enlargement of an image appearing on a CRT, the lens having sequentially from the screen end a first unit of a bi-convex element having a positive power with a strongly convex surface directed toward the screen end, a second unit of a bi-concave element having a negative power and being located at or in the vicinity of the entrance pupil position of the entire lens system, a third unit of a bi-convex element having a positive power, and a fourth unit having a negative power with a strongly concave surface directed toward the screen end.

Abstract: A projection lens having a large aperture ratio has 3 units for projecting an enlargemen of an image appearing on a CRT onto a screen. The first unit from the screen has a negative power so that the entrance pupil is moved toward the screen to thereby improve off-axis vignetting factor. The second unit consists of two positive power lens elements so that the positive power of the entire system is shared by the second unit and the temperature characteristic is improved by using a positive power glass lens element as one of the two positive power lens elements. The third unit has a negative power to correct curvature of field.

Abstract: A compact projection lens for projecting an enlargement of an image appearing on a cathode ray tube (CRT) onto the screen. The projection lens has a first lens having a positive optical power and at least one aspheric surface, surface of the first lens that faces the screen being convex, a second lens having bi-convex surfaces and a positive optical power, and a third lens having a negative optical power and an aspheric concave surface facing the second lens. The focal length f.sub.1 of the first lens and the focal length f.sub.2 of the second lens are selected for satisfying a condition of0.55<f.sub.1 /f.sub.2 <1.2.

Abstract: In order to accurately control the operation of the engine while still achieving near optimal swirl rate control, the swirl is controlled by a valve which is separate from the engine throttle valve and which is basically controlled in response to the pressure prevailing across the same. Various operating parameters such as the instant air-fuel ratio of the charge being combusted in the combustion chambers are utilized to modify prerecorded values to those which will induce the best setting for the valve.

Abstract: A filter is disposed in the exhaust passage of an internal combustion engine in order to trap particles suspended in exhaust gas. A burner serves to burn off the particles deposited on the filter. Either the pressure in the exhaust passage at a point upstream of the filter or the pressure difference in the exhaust passage across the filter is selectively sensed. In place of sensing the pressure difference, the pressure in the exhaust passage at a point downstream of the filter may be sensed. The ratio between the upstream pressure and the pressure difference, or the ratio between the upstream pressure and downstream pressure is determined an as indication of the degree of clogging of the filter. The burner is operated on the basis of this ratio.

Abstract: A projection lens apparatus for projecting an image from a CRT onto a remote screen. The lens apparatus is basically a Petzval type for a large aperture ratio and comprises three lenses. The first lens is a plastic lens having at least one aspherical surface and the third lens has a bi-aspherical surface. To reduce the thermal drift of the focal position, the second lens is a glass lens, having relatively largely positive optical power.

Abstract: A system for controlling a coolant temperature of an internal combustion engine comprises means for detecting operating condition of an engine, means for setting a different target coolant temperature for the detected operating condition, a flow control valve disposed in a coolant recirculating passage, and means for effecting a feedback control of opening degree of said flow control valve in such a manner as to adjust the actual coolant temperature toward the target coolant temperature.

Abstract: A fuel supply system for an internal combustion engine is disclosed which includes a single fuel injection valve provided at the area at which a plurality of branch passages of an intake manifold join, and a pressure regulator which regulates the pressure of the fuel supplied to the fuel injection valve in accordance with a vacuum pressure in an intake manifold.According to this system, during low load condition, the pressure of the fuel supplied to the fuel injection valve is held within a range of levels lower than that appearing during high load conditions, thereby increasing the duration during which the fuel injection valve is opened in synchronism with the operation of each cylinder. Thereby, this system makes it possible to uniformly supply fuel to each cylinder for all running conditions of the vehicle.

Abstract: An internal combustion engine operable on two kinds of fuel properly selected according to engine operating conditions. A control system is provided which controls the total amount of fuel supplied to the engine in response to intake air flow and controls the ratio between the amounts of the two kinds of fuel supplied to the engine in response to engine load.

Abstract: Disclosed is a piston ring assembly for an automotive internal combustion engine, including a first compression ring having double-stepped mating ends for reducing the quantity of blow-by gas, and a second compression ring which is constructed in the form of a double-ring structure adapted for reducing the quantity of oil consumption.

Abstract: A spark-ignition internal combustion engine with multiple plugs is operated at an air-fuel ratio around the stoichometric under a high EGR rate higher than EGR limits for stable operation in a single spark plug ignition engine.

Abstract: A projection television apparatus having a retrofocus type projection lens system which has a sufficiently long back focus, a small F number and a large distortion. The lens system is constructed with five components and five lenses and comprises a first lens which is a negative meniscus lens that has at its screen side a convex surface, a second lens which is a biconvex lens, a third lens which is a biconcave lens, a fourth lens which is a positive lens, and a fifth lens which is a biconvex lens, and which is defined by the following four conditions, i.e.1.4f<.vertline.f.sub.1 .vertline.<1.9f (i)0.35f<d.sub.2 <0.55f (ii)0.8f<r.sub.3 <1.2f (iii)0.15f<d.sub.4 <0.35f (iv)where f is the composite focal length of the total lens system, f.sub.1 is the focal length of the first lens, d.sub.2 is the air space between the first lens and the second lens, d.sub.4 is the air space between the second lens and the third lens, and r.sub.