Abstract: A visor assembly structured to effectively shade a viewing screen of a monitor of the type utilized in a personal computer or like equipment to the extent of at least partially shading light from a viewing screen of the equipment thereby preventing unwanted glare appearing thereon. The visor assembly is adjustably mounted along an upper periphery of a housing of the viewing screen and adjustable longitudinally to accommodate monitors or screen housings of various sizes and outwardly in angularly overlying relation to the viewing screen for optimum positioning to prevent glare thereon.

Abstract: A double Gauss reduction lens is optimized for projecting line images from an object plane onto a photosensor array. The six elements, four-component lens has a numeral focal length of 550 mm, a field of view of 17.degree. at the numeral 550 mm overall object to image conjugate length and a magnification of 0.1102. The lens is characterized by a high modulation transfer fequency, large depth of focus and low distortion.

Abstract: An f..theta. lens system which incorporates the advantages of a telecentric optical system and which is also achromatized so as to permit its use with a multi-mode laser. The lens system includes, in order from the light source side, of a first lens unit composed of one or two lens elements and which has a negative refractive power with a concave surface directed toward the light source side, a second lens unit composed of a positive meniscus lens having a convex surface directed toward the image side, a third lens unit composed of two positive lens elements and one negative lens element and which has a positive refractive power, and a fourth lens unit composed of two plano-convex lens elements and which is spaced a long distance from the third lens unit so as to be located at a position close to the image plane.

Abstract: An optical system is provided implementing a field correction apparatus. The system includes a rotating support driven by a motor. A plurality of focussing lenses are circumferentially spaced about the axis of rotation of the support. As the support rotates, each focussing lens successively passes over a record medium in an arcuate path. The support is also provided with a pyramidal distributing mirror having a number of reflecting surfaces. Each reflecting surface of the disturbing mirror is associated with one of the focussing lenses. The pyramidal distributing mirror is mounted on the center of the support and receives an optical beam on one of its reflecting surfaces. The optical beam is conveyed to the reflecting surface associated with the focussing lens passing over the record medium in a plane that includes the axis of rotation of the support. The optical beam is also directed to the reflecting surface at an angle to the axis of rotation.

Abstract: A zoom lens comprising, from front to rear, a first lens group having a positive refractive power and fixed relative to an optical axis, a second lens group having a negative refractive power, a third lens group fixed relative to the optical axis and having a positive refractive power, and a fourth lens group having a positive refractive power, the second and fourth lens groups being axially moved to effect zooming, and the fourth lens group being also made to axially move to effect focusing.

Abstract: A copier lens system having a large aperture has a basic structure of 6-unit-6-element arrangement which is constructed by separating the first and second lenses of the orthmeta type lens system.

Abstract: A photo-taking lens of a two-unit, five element construction for an underwater camera comprises, in succession from the object side, a fixed forward unit having a first element having a meniscus lens having its convex surface facing the object side and having a negative refractive power when the medium on the object side is water, and a rearward unit having a positive second element having a biconvex positive lens, a negative third element having a biconcave negative lens, a positive fourth element having a positive meniscus lens having its convex surface facing the image side, and a positive fifth element having a positive lens having its surface of sharper curvature facing the image side, and movable as a whole along the optic axis for focussing. The photo-taking lens satisfies the following condition:0.75f<r.sub.2 <2f,where f is the rearward focal length of the entire system during focusing at infinity when the medium on the object side is water, and r.sub.

Abstract: An apochromat type objective lenses, which is applied to an astronomical telescope; a telephoto lens for cameras or the like, comprising a semiapochromatic first lens system synthesized lens composed of two lenses in one group consisting of a convex lens and a concave lens, and an achromatic second lens system synthesized lens composed of two lenses in one group consisting of a concave lens and a convex lens, which is arranged in a spaced apart relation behind the semiapochromatic first lens system; the first and second lens systems being fulfilled with the condition below: ##EQU1## where, f, f: the focal length of the first and second lens systems,K, K: the proportion of the residual secondary chromatic aberration of the first and second lens systems, andL: the mutual spacing between respective lens systems.

Abstract: A compact zoom lens comprising, from front to rear, a first lens unit of positive power for focusing, a second lens unit of negative power axially movable in one direction when zooming from one end of a range of image magnification to the other, a third lens unit of positive power axially movable in a path convex toward the rear to maintain the constant position of an image surface which shifts with zooming, and a fourth lens unit of positive power for forming an image which remains stationary during zooming, wherein a fixed diaphragm is arranged in a space between the second and third lens units.

Abstract: To minimize the size of a front conversion lens, an aperture stop is arranged on the object side of a master lens, and the front conversion lens is made releasably attachable.

Abstract: A zoom lens includes, in order from an object, a first lens unit having positive refracting power, a second lens unit having negative refracting power, and a third lens unit having positive refracting power. The second lens unit has a paraxial lateral magnification greater than 1 at all times. The third lens unit is fixed. The distance between the first and second lens units and the distance between the second and third lens units are relatively varied to vary the focal length of the entire lens system.

Abstract: Two movable groups of lenses forming a variator are controlled by means of a computer and these groups are accordingly subjected not only to the necessary displacements of each group for the progressive variations of focal length but also to a complementary longitudinal displacement for applying to the objective-lens system a focal-length multiplier coefficient having a value chosen by the operator. The device in accordance with the invention comprises a control system associated with a computer and capable of subjecting the two movable groups of lenses to a complementary longitudinal displacement in order to apply a focal length multiplier coefficient to the objective-lens system, another function of the computer being to produce the desired variation of the iris and the complementary displacements of the focusing groups in respect of each focal length. The longest possible focal length can thus be chosen as a function either of the selected numerical aperture or of the field to be covered.

Abstract: An optical system for illuminating an object, including an entrance pupil for receiving light from a light source, an exit pupil for passing the light received to an object to be illuminated, and an optical axis which extends through the optical sytem to the light source and the object respectively, wherein the entrance height of the light received in the entrance pupil is substantially proportioned to the tangent of the exit angle in the exit pupil.

Abstract: A telephoto lens comprising, from front to rear, a first lens unit including a lens of negative power with its rear surface concave toward the rear and whose overall power is positive, a second lens unit of negative power axially movable for focusing, and a third lens unit of positive overall refractive power having a negative lens whose front-most lens surface is concave toward the front and at least two positive lenses.

Abstract: An optical system simulates the optical effect of traveling over a large distance on light traveling from a first reference surface to a second reference surface. The first and second reference surfaces are relatively closely spaced. A first afocal magnifying lens system receives light from the first reference surface and provides a magnification ratio of M.sub.1. A second afocal magnifying lens system, spaced from the first afocal magnifying lens system by a predetermined distance D, receives light from the from the first afocal magnifying lens system and transmits it to the second reference surface with a magnification ratio of M.sub.2. The length of the distance which is simulated is related to the magnification ratio M.sub.1 of the first afocal magnifying lens system and to the predetermined distance D. The scale of the output image is related to magnification ratio M.sub.2.

Abstract: Disclosed is a graded index lens array which gives good resolution even if its end surfaces are not fully polished during its manufacture and which is less likely to suffer loss in resolution due to damage to its surfaces comprising a plurality of graded index lenses made of a synthetic resin and arranged in parallel, characterized in that at least one end surface of the lens array is coated with a cured film formed from a cross-linkable resin consisting essentially of a multifunctional compound having at least two (meth)acryloyloxy groups per molecule, and a fluorinated alkyl (meth)acrylate.

Abstract: An apparatus for adjusting light beam direction comprises, for instance, two prisms, i.e., a first and a second prisms arranged, in order, along an incident direction of light beam; an incident face of the first prism being parallel to a plane which is assumed to rotate an imaginary vertical plane perpendicular to the incident direction around a rotational axis by a first acute angle; an outgoing face of the first prism being parallel to a plane which is assumed to rotate the vertical plane around the axis by a second acute angle larger than the first one in the same direction as the latter; an incident face of the second prism being parallel to the outgoing face of the first prism and an outgoing face of the second prism being parallel to the incident face of the first prism, at the zero-adjusting state; and at least one of these prisms being able to adjustably rotate around the rotational axis.

Abstract: A gradient index lens includes a first surface comprising a convex surface, a second surface comprising a convex surface, the convex surface of the second surface sharing the center of curvature with the convex surface of the first surface, and an index gradient N(.rho.) formed in the medium of the lens. The index gradient N(.rho.) is expressed asN(.rho.)=N.sub.0 +N.sub.2 .rho..sup.2 +N.sub.3 .rho..sup.3 N.sub.4 .rho..sup.4 +N.sub.5 .rho..sup.5 + . . .where N.sub.0 is the refractive index at the center of curvature, Nk (k=2, 3, 4, . . . ) are the index gradient coefficients, and .rho. is the distance from the center of curvature, and at least one of the index gradient coefficients Nk in which k.gtoreq.3 is greater than 0. The lens satisfies the following conditions:1.45<N.sub.0 <1.9-0.4<N.sub.2 f.sup.2 <-0.2where f is the focal length of the lens.

Abstract: A preobjective scanning optical system for use with a rotating mirror scanner employing LEDs or lasers to electronically reproduce photographs. The optical system includes a doublet disposed before the mirror and a triplet disposed after the mirror. Instead of collimating, the first optical system along with the mirror forms a virtual, image of the LEDs or lasers which travels along a curved path as the scanner rotates and includes a first and a second lens which, in combination, correct the image for on-axis spherical and axial color aberrations. The triplet has net positive power and its three lenses, in combination, correct for off-axis aberrations such as astigmatism, coma, and lateral color aberration but can be under-corrected for field curvature because its object is the curved virtual image.

Abstract: A collimator lens has a small numerical aperture and a specific focal length. One of the surfaces of the lens is planar and the other surface is aspherical. The aspherical surface is defined by a series expansion with only a few even terms.