Abstract: An objective of variable focal length includes a plurality of lens units of which the first, counting from front, is of negative power and the second is of positive power. At least the first and second lens units are moved with variation of the air separation therebetween to vary the focal length of the entire system. The objective is characterized in that at least one of the lens units is included with at least one refractive index distribution type lens arranged on the common optical axis of the other lenses.

Abstract: An optical system comprising a plurality of lens components, wherein at least one of the components is a convex lens and has a radial gradient of refractive index in such a cross section that the refractive index increases toward the margin, so that it behaves as a lens of negative power.

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 variable focal length objective having a plurality of lens units with at least one unit separation being varied to vary the focal length of the entire system, in which at least one of the plurality of lens units has at least gradient-index lens having a refractive index distribution of the form: N(h)=N.sub.0 +N.sub.1 h.sup.2 +N.sub.2 h.sup.4 +N.sub.3 h.sup.6 + . . . where h is the height from the optical axis, N.sub.0 is the refractive index on the optical axis, and N.sub.1, N.sub.2, N.sub.3, . . . are constants, satisfying the following conditions:.phi..sub.G .multidot.N.sub.1 <0K.multidot..phi..sub.G .multidot.N.sub.2 <0where .phi..sub.G is the refractive power of that lens unit which has that gradient-index lens, and K is +1 or -1 when the stronger of the curvatures of both surfaces of that gradient-index lens is convex or concave to the air respectively.

Abstract: A lens system has a lens unit comprising a positive lens and a negative lens. The positive lens has an index distribution in the direction of the optic axis. The value of the index gradient for a light having a short wavelength in the vicinity of the vertex of at least one convex surface of the positive lens is smaller than the value of the index gradient for a light having a long wavelength.

Abstract: A variable focal length objective of which at least one of a pulrality of lens units is moved to vary the image magnification, wherein at least one of the plurality of lens units has at least one refractive index distribution type lens provided with a condition of N.sub.1 >0 as, taking the distance from the optical axis to a radial direction as h, the refractive index distribution is expressed by N(h)=N.sub.0 +N.sub.1 h.sup.2 +N.sub.2 h.sup.4 +N.sub.3 h.sup.6 +. . . (N.sub.0, N.sub.1, N.sub.2 . . . are constants), and satisfies the following conditions: ##EQU1## where fmax: the maximum focal length;fmin: the minimum focal length;Lmin: the optical total length when the total length is shortest;Y: the maximum image height;N.sub.1 *: the coefficient of h.sup.2 of the refractive index distribution type lens having a refractive index distribution of N.sub.1 >0;D*: the lens thickness of the refractive index distribution type lens having the refractive index distribution of N.sub.1 >0.

Abstract: An imaging lens formed by two lenses consisting of a medium whose refractive index continuously varies in conformity with the distance from the optic axis comprises, for example, a first lens disposed on the object side, the first lens having a refractive index distribution in which the refractive index thereof increases away from the optic axis, the shape of the first lens being a shape in which the thickness thereof is greatest on the optic axis and decreases away from the optic axis, and a second lens disposed on the image side, the second lens having a refractive index distribution in which the refractive index thereof decreases away from the optic axis, the shape of the second lens being a shape in which the thickness thereof is smallest on the optic axis and increases away from the optic axis.

Abstract: A distributed index of refraction type lens is applied to a focusing lens suitable for a photographing lens to correct various aberrations. One distributed index of refraction type lens and a single-lens (including a bonded lens) of homogeneous medium are combined such that the distributed index of refraction type lens has an index of refraction distribution which continuously decreases as a light goes away from an optical axis, and has a thickness distribution which is smallest on the optical axis of the lens and increases as it goes away from the optical axis. Thus, the aberrations in the whole system can be corrected by the single distributed index of refraction type lens and a light and easy-to-manufacture focusing lens is provided.

Abstract: A zoom lens including, from front to rear, a positive first component, a negative second component, a positive third component and a fourth component which is stationary during zooming. In some zoom lenses, a fifth component may be positioned behind the fourth component, in which, during zooming, the fourth component is movable and the fifth component is stationary. The separation between the first and second components and the separation between the second and third components varies to effect zooming. The third component is composed of, from front to rear, two positive lenses, a negative meniscus lens having a divergent cemented surface convex towards the front, and a positive lens with its rear surface having the stronger curvature. Minimization of bulk and size and an increase of the image magnification range of the zoom lens is achieved while preserving correction if aberrations.

Abstract: A dielectric resonator employing the TM mode as its resonance mode, which is provided with a dielectric base plate on which an electronic circuit is formed and a pair of electrodes formed in face-to-face relation to each other on respective major surfaces of the dielectric base plate. A plurality of through-holes are defined between the pair of electrodes on their circumferential portions and both of the electrodes are connected with each other by way of conductive material formed on the inner surfaces of the through-holes.

Abstract: A gradient index single lens has a first surface convex toward the object side, the first surface lying on the object side when the lens is used at a reduction magnification, a second surface concave toward the image side, the second surface lying on the image side when the lens is used at a reduction magnification, and an index distribution formed in the interior of the lens, the index distribution having a sphere symmetrical distribution about a certain point on the optic axis.

Abstract: A stripline filter includes a cylindrical substrate made of a dielectric material and having inner and outer surfaces with opposite ends thereof opened. A ground electrode is deposited on the inner surface, and on the inner surface, interdigitated electrodes are deposited. Alternately, the ground electrode may be deposited on the outer surface, and the interdigitated electrodes may be deposited on the inner surface. Thus, the stripline filter can be arranged in a compact size. Also, the ground electrode provided on the outer surface prevents electromagnetic waves generated from the interdigitated electrodes from being emitted out.

Abstract: A dielectric resonator provided with a plurality of dielectric resonator units which are combined into one unit, with a boundary being formed between adjacent dielectric resonator units, a connecting material for rigidly connecting said adjacent dielectric resonator units to each other, a support member for placing said dielectric resonator units thereon, a metallic conductive case accommodating said dielectric resonator units on said support member therein, and input and output members for electrical connection of said dielectric resonator with an external circuit, whereby a resonant frequency of spurious mode is shifted into a frequency zone higher than a resonant point by causing said spurious mode to pass through boundary surfaces or layers.

Abstract: A projection device has an illuminating system for illuminating an object, and an index distribution type lens for projecting the image of the object. The lens has a refractive index distribution substantially proportional to the square of the distance from the optic axis in a cross-section perpendicular to the optic axis and a refractive index distribution monotonously varying in the direction of the optic axis.

Abstract: A gradient index lens includes first and second flat end faces. A refractive index N(.gamma.) at a position deviated by a distance .gamma. from an optical axis of the lens is given asN(.gamma.)=N.sub.0 +N.sub.1 .gamma..sup.2 +N.sub.2 .gamma..sup.4 + . . .for N.sub.1 <0where N.sub.0, N.sub.1, N.sub.2, . . . are constants, and the following conditions are satisfied: ##EQU1## where f is a focal length of the lens, a is an effective lens diameter, Sk' is a work distance, and .lambda. is a wavelength in units of microns.

Abstract: An in-focus position detecting optical system comprises a focus lens for imaging the image of an object to be photographed at an imaging position. The focus lens has integrally formed therewith a light projecting lens for projecting a distance measuring light flux onto the object to be photographed. The light projecting lens has the same focal length as that of the focus lens.

Abstract: A zoom lens comprising, from front to rear, a positive first lens component, a negative second lens component, a positive third lens component and an image forming or fourth lens component, wherein as zooming occurs from the wide angle to the telephoto position, the first and third lens components are moved axially forward, while the second lens component is held stationary. By giving appropriately specified ranges for numerical values of the focal lengths of the first to third lens components, improvements in the compactness are achieved while still permitting good correction of aberrations.