Abstract: A color cathode ray tube including a panel section having a phosphor layer formed on an internal surface thereof, a neck portion having an electron gun assembly for emission of three electron beams therein, and a funnel section connecting the panel section and the neck portion. The electron gun assembly includes three cathodes and a plurality of grid electrodes disposed along a tube axis. The grid electrodes includes at least one plate-shaped electrode which has a fixed support structure. The plate-shaped electrode has three bulged portions along an electron beam passage, a first electron beam passage hole being formed in a respective bulged portion and a second electron beam passage being hole formed in a top face portion of a respective bulge portion. A diameter of the first electron beam passage hole is greater than a diameter of the second electron beam passage hole.

Abstract: A color cathode ray tube includes a phosphor screen, a three-beam in-line electron gun, a beam deflection device, and a convergence correction device disposed on a phosphor screen side of the electron gun. The convergence correction device includes a first pair of magnetic pieces positioned on a tube-neck wall side of side electron beams and a second pair of magnetic pieces positioned on opposite sides of a center electron beam, in the in-line direction. The first pair of magnetic pieces each have a first pair of protruding portions extending toward an adjacent one of the second pair of magnetic pieces, and the first pair of protruding portions are arranged on opposite sides of a corresponding one of the side electron beams in a direction perpendicular to the in-line direction.

Abstract: A color cathode ray tube including a panel section having a phosphor layer formed on an internal surface thereof, a neck portion having an electron gun assembly for emission of three electron beams therein, and a funnel section connecting the panel section and the neck portion. The electron gun assembly includes three cathodes and a plurality of grid electrodes disposed along a tube axis. The grid electrodes includes at least one plate-shaped electrode which has a fixed support structure. The plate-shaped electrode has three bulged portions along an electron beam passage, a first electron beam passage hole being formed in a respective bulged portion and a second electron beam passage being hole formed in a top face portion of a respective bulge portion. A diameter of the first electron beam passage hole is greater than a diameter of the second electron beam passage hole.

Abstract: A color cathode ray tube includes a panel section having an internal surface with a phosphor layer formed thereon and a neck portion accommodating therein an electron gun assembly for emission of a plurality of electron beams plus a funnel section connecting the panel section and the neck portion together, wherein the electron gun assembly is designed to have a plate-shaped electrode with a plurality of electron beam passage holes corresponding in the number to the electron beams. The plate electrode has cylindrical bulged portions projecting in a way corresponding to the plurality of electron beams, each of which portion has its top face in which an electron beam opening or hole is formed. The present invention provides a color cathode ray tube comprising a readily manufacturable high-resolution electron gun assembly.

Abstract: A color cathode ray tube having electron gun with a plurality of electrodes for generating and focusing three in-line electron beams toward a phosphor screen. A deflection device is mounted between a funnel portion and a neck portion for deflecting the three electron beams in horizontal and vertical directions, and a convergence correction device including a plurality of magnetic pieces positioned with respect to the three electron beams in an in-line direction of the three electron beams in magnetic deflection fields generated by the deflection device.

Abstract: A color cathode ray tube includes a vacuum envelope formed by a panel, neck and funnel portions. The cathode ray tube includes a phosphor screen, a shadow mask, an electron gun and a deflection device. The cathode ray tube further includes a convergence correction device having a plurality of magnetic pieces positioned on opposite sides of each of the three electron beams in an in-line direction of the electron beams in a magnetic deflection fields generated by the deflection device. The plurality of magnetic pieces include a first pair of magnetic pieces positioned on a neck wall side of each of side electron beams in the in-line direction and a second pair of magnetic pieces positioned on opposite sides of a center electron beam of the three electron beams in the in-line direction. The plurality of magnetic pieces are configured so as to locally modify the magnetic deflection fields to make three rasters formed on the phosphor screen by the three electron beams coincident with each other.

Abstract: A microscope objective comprising a first, second, third fourth and fifth lenses, in which the first lens is a positive lens, the second lens is a positive meniscus lens, the third lens is a negative lens, the fourth lens is a positive meniscus lens and the fifth lens is a positive lens, and satisfying the following conditions for which the number of lenses constituting the lens system is small, working distance is large and resolving power is extremely high.(1) 0.14f<d3<05f(2)0.28f<.vertline.r.sub.2 .vertline.<0.69f0.28f<.vertline.r.sub.8 .vertline.<0.69f(3) 0.5<r.sub.4 /r.sub.3 <2.7(4) 0.4d.sub.4 <d.sub.5 /n.sub.3 +d.sub.6 +d.sub.7 /n.sub.4 <2.5d.sub.4(5) .nu..sub.3 <35, .nu..sub.1 >50, n.sub.1 >1.

Abstract: A microscope objective lens system which comprises a front and a rear lens group, the former comprising a first positive meniscus lens component, a second positive lens component, a third positive cemented lens component and a fourth positive cemented lens component, and the latter comprising a fifth cemented lens component, the system enabling to achieve the flattening of an image plane widely towards the surrounding area of visual field.

Abstract: An objective lens system for microscopes having a large N.A. and a long working distance comprising a first positive lens component, a second single or cemented meniscus lens component, a third negative cemented meniscus lens component and a fourth positive lens component. Said objective lens system is so designed as to satisfy the conditions enumerated hereunder:(1) f/4<d.sub.6 +d.sub.7 <f/1.5(2) 0.1f<r.sub.5 <0.35f0.1f<-r.sub.6 <0.35f(3) .nu..sub.2 >40.nu..sub.5' .nu..sub.6 >55.nu..sub.

Abstract: A low magnification microscope objective lens system which comprises a small number of lenses and wherein lateral chromatic aberration is controlled to a level similar to that in high magnification microscope objective lens systems while maintaining flatness of image.

Abstract: A microscope objective comprising a first, second, third and fourth lens components, in which the first lens component is a biconcave lens, the second lens component is a biconvex lens, the third lens component is a positive cemented meniscus doublet, the fourth lens component is a positive lens, and satisfying the following conditions for which N. A. is large, working distance is long and flatness of image is favorable.0.15<.vertline.r.sub.2 /r.sub.1 .vertline., 0.5<.vertline.r.sub.5 /r.sub.7 .vertline.<2.5 (1)0.4d.sub.4<d.sub.3 /n.sub.2 +d.sub.5 /n.sub.3 +d.sub.6 /n.sub.4 <3.5d.sub.4 (2)d.sub.2 <2.5d.sub.3 /n.sub.2 (3).nu..sub.1 >55, n.sub.1 <1.58 (4).nu..sub.2 <50, n.sub.2 >1.7035<.vertline..nu..sub.4 -.nu..sub.3 .vertline., .nu..sub.4 >60 (5)n.sub.3 <1.

Abstract: A sturdy optical mold for reproducing optical curved surfaces in the shape corresponding to that of an optical prototype comprising a resin layer formed on a base and a metallic layer formed on said resin layer, and a method for manufacturing an optical mold for reproducing optical curved surfaces in the shape corresponding to that of an optical prototype comprising forming layers of different metals on the surface of an optical prototype, dissolving one of said layers for releasing the other layer and fixing said released layer onto a base with a bonding agent.

Abstract: A low magnification microscopic objective comprising two components of four elements for which radii of curvature on respective lens surfaces are selected as large as possible and wherein various aberrations are favorably corrected.

Abstract: A lens mount for a microscope objective comprising a correcting ring, which is used for moving a part of lenses constituting the objective along the optical axis in order to correct deterioration of the image, and a friction band arranged round the outer surface of said correcting ring and made of material such as rubber so that said correcting ring can be easily rotated by rubbing said friction band by a finger bulb.

Abstract: A microscope objective with correcting means comprising a front lens group arranged on the object side of a pre-determined airspace and rear lens group arranged on the image side of said airspace and arranged to correct aberrations, which will be caused by difference in thickness of the cover glass, by varying said airspace moving the rear lens group in respect to the front lens group so that a favourable image can be obtained for observation.

Abstract: A telephoto lens system comprising a front lens group having a strong positive power and a rear lens group having a strong negative power and satisfying the following conditions, said telephoto lens system thus having a small telephoto ratio and aberrations corrected quite favorably.1. 0.32f < d.sub.6 < 0.40f2. 1.25f < r.sub.23. .vertline. 1/r.sub.6 .vertline.< 0.2/f4. 0.3 < - r.sub.3 /r.sub. 4 < 0.95. 0.9 < r.sub.1 /r.sub.5 < 1.16. 0.008f < d.sub.2 + d.sub.4 < 0.015f7. n.sub.1 , n.sub.3 < 1.55 , n.sub.2 > 1.78. .vertline..nu..sub.1 - .nu..sub.2 .vertline. > 35 , .vertline..nu..sub.3 - .nu..sub.2 .vertline.