Abstract: A color cathode ray tube having at least an electron gun, constituted by a cathode for forming a plurality of electron beams arranged in-line, and a focusing electrode and an anode constituting a main lens for focusing and accelerating the electron beams and a fluorescent screen. The focusing electrode includes at least a first division electrode and a second division electrode arranged with a gap for controlling a scanning speed of the electron beams in common. The second division electrode is opposed to the anode and has, in an opposed surface thereof, a single opening for passing the plurality of electron beams in common. A length of the first division electrode in the axial direction of the tube is longer than a length of the second division electrode in the axial direction of the tube.

Abstract: A color cathode ray tube having at least an electron gun, constituted by a cathode for forming a plurality of electron beams arranged in-line, and a focusing electrode and an anode constituting a main lens for focusing and accelerating the electron beams and a fluorescent screen. The focusing electrode includes at least a first division electrode and a second division electrode arranged with a gap for controlling a scanning speed of the electron beams in common. The second division electrode is opposed to the anode and has, in an opposed surface thereof, a single opening for passing the plurality of electron beams in common. A length of the first division electrode in the axial direction of the tube is longer than a length of the second division electrode in the axial direction of the tube.

Abstract: A color cathode ray tube having at least an electron gun and a fluorescent screen. The electron gun forms a plurality of electron beams arranged in line and includes a focusing electrode and an anode having a gap and providing a main lens for focusing and accelerating the electron beams. The focusing electrode includes at least a first division electrode and a second division electrode having the same potential and arranged with a gap in the axial direction of the tube. The second division electrode is opposed to said anode and has, in the opposed surface thereof, a single opening for passing the plurality of electron beams in common. The second division electrode is opposed to the first division electrode and has, in the opposed surface thereof, individual electron beam passing openings for the respective electron beams.

Abstract: A color cathode ray tube has at least an electron gun, constituted by a cathode for forming a plurality of electron beams arranged in line and a plurality of electrodes, and a fluorescent screen, wherein the plurality of electrodes including an anode are arranged in the axial direction of the tube and have dissimilar potentials, and a main lens is constituted of the anode and another electrode neighboring the anode. The electrode neighboring the anode includes at least two division electrodes having the same potential and being arranged with a gap in the axial direction of the tube, and one of the division electrodes is opposed to the anode and has, in the opposed surface thereof, a single opening for passing the plurality of electron beams in common. The one division electrode opposed to the anode has a length in the axial direction of the tube that is from about 1.0 to about 1.6 times as great as the diameter of the single opening in a direction at right angles with the in-line direction.

Abstract: An objective lens system for microscopes comprising a front lens group consisting of a first positive cemented doublet component, a second positive single-element or cemented doublet component and a third positive single-element or cemented doublet component, and a rear lens group consisting only of a negative three-element cemented lens component, said objective lens system having a large N.A. value and being so adapted as to be usable for fluorescence microscopy by using a glass material showing, at a thickness of 10 mm, a transmittance of 80% or higher at wavelength .lambda.=365 nm which enhances transmittance of the entire lens system above 60%.

Abstract: An objective lens system for microscopes comprising a front lens group consisting of a first positive meniscus lens component and a second positive cemented doublet component, and a rear lens group consisting of a third lens component having positive refractive power and a fourth lens component having positive refractive power, said objective lens system having a sufficiently large NA and being made of a glass material showing high transmittance for rays at short wavelengths.

Abstract: An achromat microscope objective with high magnification comprising a first, second, third and fourth lens components, the first lens component being a comparatively thick meniscus lens, the second lens component being a positive meniscus lens with comparatively small thickness, the third lens component being a cemented doublet, the fourth lens component being a cemented doublet, aberrations especially astigmatic difference and curvature of field of the microscope objective being corrected favorably.

Abstract: An objective lens system for microscopes which has a large numerical aperture and a long working distance and wherein the secondary spectrum is sufficiently minimized and curvature of field, coma, etc. are favorably corrected over a wide range of visual field. Said objective lens system comprises a first single-element or cemented doublet lens component and at least three lens components, i.e., two cemented meniscus lens components so arranged as to face their concave surfaces each other and a cemented three-element lens component.

Abstract: An objective lens system for microscopes consisting of a front lens group comprising a positive lens component and a meniscus lens component having a concave surface on the image side, and a rear lens group comprising at least a meniscus cemented lens component, a positive lens component and at least one cemented three-element lens component. Said objective lens system is so designed as to have a large numerical aperture, secondary spectrum sufficiently minimized, a long working distance and curvature of field, coma etc. favorably corrected over a wide range of visual field.

Abstract: A microscope objective lens system which comprises a first lens component of a positive lens, a second lens component of a positive meniscus lens having its convex surface faced to the object side, a third lens component of a negative lens, a fourth lens component of a positive meniscus lens having its concave surface faced to the object side, and fifth lens component of a double-convex lens, in which image plane through the objective lens system can coincide with a reverse-traced image plane through an eyepiece lens system and which enables observation with a flat image plane through the eyepiece lens system.