Abstract: In an image pickup lens including a lens body, at least one of faces of the lens body is formed into an aspherical shape, and at least one of a first face of the lens body adjacent an object and a second face of said lens body adjacent an image pickup surface is a Fresnel face. Thus, the image pickup lens can be reduced in size, and the optical characteristics of the image pickup lens can be enhanced remarkably in a simple structure.

Abstract: An optical lens device assembly containing an optical lens device and an optical device sealed without causing complication of optical module configurations is provided. In the optical lens device assembly, a resin member having light transmittance is used to fill in space between the optical lens device and the optical device to be optically coupled to the optical lens device. The resin member is made from a resin material having a refractive index being different from that of the optical lens device. The resin member is used to seal a clearance between optical planes, which face each other, of the optical lens device and the optical device, and to mechanically couple the optical lens device to the optical device.

Abstract: A lens barrel having a cam barrel is disclosed. The cam barrel is molded by die-cutting in radial and other directions relative to the optical axis so as to have raised cams without undercuts if the raised cams are even partially lined up fore and behind one another along the optical axis, and there is no parting line in either the cam grooves nor the raised cams. The cam barrel has its outer surface provided with raised cams and is made of synthetic resin, and each of the raised cams has at least one of cam faces inclined toward an opposite cam face off a radial direction relative to an optical axis of the cam barrel.

Abstract: The invention relates to a high-performance, large-aperture yet wide-angle zoom lens system that can be used with an electronic image pickup device in particular, a method for focusing the same. In particular, the invention is concerned with a high-performance, large-aperture yet wide-angle zoom lens system which has a zoom ratio of the order of 3 at a diagonal field angle of 75° at its wide-angle end, so that it can be used with a single-lens reflex camera using an electronic image pickup device with the number of pixels being of the order of 6,000,000. The zoom lens system comprises a first lens group G1 having negative refracting power, a second lens group G2 having positive refracting power, a third lens group G3 having negative refracting power, a fourth lens group G4 having positive refracting power and a fifth lens group G5 having positive refracting power. Upon movement of an object point, focusing is carried out with the fifth lens group G5.

Abstract: A variable-focus lens system includes a negative front lens group, and a positive rear lens group. The focal length of the variable-focus lens system is varied by changing the distance between the front and said rear lens groups. The lens system satisfies the following conditions: −3.0<fx/Fw<−2.5 3.0<fy/Fw<3.5 wherein fx designates the focal length of the front lens group, which is less than zero; fy designates the focal length of the rear lens group, which is greater than zero; and Fw designates the focal length of the entire variable-focus lens system at the short focal length extremity.

Abstract: A zoom lens mechanism includes a switching lens group frame supporting a first sub-lens group frame and a second sub-lens group frame which support first and second sub-sub-lens groups, respectively; a lens group shift mechanism for causing the first and second sub-lens group frames to linearly move to a mutually close position or a mutually distant position, with respect to the optical axis direction, in accordance with relative rotation between the first sub-lens group frame and the second sub-lens group frame; and a focusing mechanism which integrally moves the first sub-lens group frame and the second sub-lens group frame in the optical axis direction while maintaining a distance therebetween after the first and the second sub-lens group frames are moved to one of the mutually close position and the mutually distant position by the lens group shift mechanism.

Abstract: A zoom lens system includes a first lens group, a second lens group, a third lens group, and a fourth lens group. Zooming is performed by moving each of the first through fourth lens groups in the optical axis direction, and the zoom lens system satisfies the following conditions: 1.1<f23T/f23W<1.8  (1) 0.2<LD23W/fw<0.45  (2) 0.01<(D23W−D23T)/fT<0.

Abstract: Lens barrel or an optical apparatus with a lens barrel comprising: a lens unit having an optical axis and forming an optical image, the lens unit having a fixed lens component and a movable lens component; and a lens housing for containing the lens unit, the lens housing having a first housing and a second housing divided in a direction along the optical axis; wherein: the first housing has a lens-holding portion for holding the fixed lens component; and the second housing has a pickup-device holding portion for holding an image pickup device for taking the optical image obtained by the lens unit.

Abstract: A panoramic imaging lens having an annular light incident surface formed in a substantial convex lens form; a first reflective surface formed in an annular concave mirror form to reflect light inside the lens; a second reflective surface provided at a central part inside the annular light incident surface to reflect the reflected light from the first reflective surface toward an inner part of the annular first reflective surface; and a light outgoing surface positioned at a central part inside the annular first reflective surface and opposing the second reflective surface to transmit light. A non-reflective part exerting no regular reflection of light is provided on a light path toward the light incident surface amongst light paths of light proceeding to agree with a light path of imaging light incident on and refracted at the light incident surface and proceeding inside the lens.

Abstract: Disclosed are a base plate for use for a lens sheet that can realize the unlikeliness to be cracked while the self-sustenance of the lens sheet is being maintained, the lens sheet, and a projection screen comprising that lens sheet. In a base plate, the base plate constructing a lens sheet as a base sheet for a UV-curable resin layer by being bonded to the UV-curable resin layer and being made of ductile materials, the breaking flexure by bending of the ductile material is 0.08 or more; and the Izod impact value thereof is 5 KJ/m2 or more. Also, in a base plate consisting of fragile material, there is used a material that has respective physical properties wherein when it is assumed that F (MPa) represents the shearing force of the UV-curable resin; h (m) represents the thickness of the base plate; E (MPa) represents the bending modulus of elasticity of the fragile material; and &ohgr; (dimensionless quantity) represents the breaking flexure by bending, the relationship of F/hE&ohgr;<1.5 holds true.

Abstract: Disclosed is a diffusion film comprising a transparent polymeric film base bearing a plurality of integral contiguous layers, each layer having a pattern of complex lenses on a surface thereof, at least two such contiguous layers comprising material having an index of refraction differing by at least 0.1.

Abstract: Provided is a single-focus lens with a shorter overall length which exhibits optimal optical performance chiefly for an imaging lens, and does not require a complicated fabrication technique. In the single-focus lens, consecutively arranged form an object side are a first lens having a meniscus shape and a positive refractive power, directing its concave to the object side; a second lens having a meniscus shape and including at least one aspheric surface; a third lens directing its concave to the object side and having a negative refractive power; a fourth lens directing its convex to an image side and having a positive refractive power; a fifth lens directing its convex to the image side and having a positive refractive power and a sixth lens having a meniscus shape, including at least one aspheric lens, and directing its concave to the image surface. Preferably, the second lens and the sixth lens are made of optical plastic.

Abstract: A projection lens of the following structure was invented for the purpose of providing a bright projection optical system with the F-number of approximately 2 or lower while maintaining good optical characteristics, in an image display apparatus. The projection lens is constructed of six lens units, a first lens unit L1 of a negative optical power, a second lens unit L2 of a positive optical power, a third lens unit L3 of a positive optical power, a fourth lens unit L4 of a negative optical power, a fifth lens unit L5, and a sixth lens unit L6 of a positive optical power, in the order named from the enlargement conjugate side, and four lens units (L2 to L5) out of the lens units move toward the enlargement conjugate side during zooming from the wideangle extreme to the telephoto extreme.

Abstract: A compact zoom lens system maintains sufficient image-formation capabilities at a wide-angle end of greater than 700 and at a zoom ratio of greater than about 10. The zoom lens system comprises a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group. For zooming from a wide-angle end to a telephoto end, the first to fifth lens groups are all movable. The first and third lens groups move toward the object side. Also, the spaces between the first and second lens groups and between the third and fourth lens groups widen. At least the fourth lens group or the fifth lens group makes a non-linear movement, compensating for a fluctuation of an image plane position with zooming. Focusing is carried out by moving the first and second lens groups as an integral unit.

Abstract: A projection optical system projects an enlarged image of a light valve image onto a screen. The system has, from the conjugate enlargement side: a negative front lens unit, optical path turning means (including a reflecting surface), a positive rear lens unit, and projection light preparing means, which can separate illumination and projection light, or can integrate light of different colors, or can do both. Each of the front and rear lens units includes at least one aspherical surface. The front lens unit has a negative first lens element at its conjugate-enlargement end and a negative second lens element at the conjugate reduction side of the first lens element. The rear lens unit includes a positive third lens element made of an anomalous dispersion material. The center of the light valve is not located on the optical axis of the rear lens unit.

Abstract: An ocular zoom lens is formed of three lens groups, of positive, positive, and negative refractive power, in order from the eye-point side. The second and third lens groups are moved along the optical axis in opposite directions during zooming, and the second lens group is formed of, in order from the eye-point side, a biconvex lens and a negative meniscus lens with its concave surface on the eye-point side, with the surfaces of the biconvex lens and the negative meniscus lens that face one another having different radii of curvature and being positioned on-axis with an intervening air space. Various conditions are preferably satisfied in order to ensure sufficient eye relief using a relatively small number of lens elements while providing increased freedom of design and enabling favorable correction of aberrations even for wide image angles.

Abstract: A wide-angle lens system includes a negative first lens group, and a positive second lens group. The first lens group includes a positive lens element, and a negative lens element. The wide-angle lens system satisfies the following conditions: 0<(&phgr;1-2+&phgr;2-1)/&phgr;<0.3 . . . (1); 0.5<HF/HL<0.9 . . .

Abstract: A zoom lens system including a first to third lens groups, and zooming is performed by respectively moving the first to third lens groups. The zoom lens system satisfies the following conditions: 1.3<|f1/f2|<1.8   (1) 2.0<f3/fw<3.4   (2) 1.05<m3t/m3w<1.25   (3) wherein fw: the focal length of the entire the zoom lens system at the short focal length extremity; f1: the focal length of the first lens group; f2: the focal length of the second lens group; f3: the focal length of the third lens group; m3w: the magnification of the third lens group at the short focal length extremity, when an object at infinity is in an in-focus state; m3t designates the magnification of the third lens group at the long focal length extremity, when an object at infinity is in an in-focus state.

Abstract: A bi-convex solid immersion lens is disclosed. Unlike conventional plano-convex solid immersion lenses having a flat bottom surface, the disclosed lens has a convex bottom surface. The radius of curvature of the bottom surface is smaller than that of the object to be inspected. This construction allows for a more accurate determination of the location of the inspected feature, and enhances coupling of light between the immersion lens and the inspected object. The disclosed lens is particularly useful for use in microscope for inspection of semiconductor devices and, especially flip-chip (or chip scale) packaged devices. The immersion lens can also be incorporated in a read or read/write head of optical memory media.

Abstract: A zoom lens which has good optical performance with the number of lenses reduced as a result of forming a diffraction optical surface is disclosed. The zoom lens includes, in order from object side to image side, a first lens unit consisting of a positive lens element and having a positive optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a positive optical power. When zooming is performed from a wide angle end to a telephoto end, the first lens unit and the third lens unit are moved so that, at the telephoto end, they are closer to the object side, and the second lens unit is moved so that, at the telephoto end, it is closer to the image side. The zoom lens further includes at least one diffraction optical surface.