Abstract: A method and apparatus for modulating an optical signal, and a method for fabricating such an apparatus, are disclosed. The modulator comprises a membrane, which consists of at least three layers, and a substrate, spaced to form an air gap. The layers of the membrane are characterized by a relationship between the refractive indices of the layers and the refractive index of the substrate. The membrane is suspended in a first position over the substrate by a flexible support arrangement. A biasing force is applied to the membrane and the substrate to create an electrostatic force to move the membrane towards the substrate to a second position. The reflectivity of the device to an optical signal changes as the membrane moves from the first position to the second position, thereby modulating the signal.

Abstract: Modulated interference effects arising when laser beams are modulated by photoelastic modulators are substantially eliminated by methods and apparatus that extract from the detected beam the modulated, interfering light that emanates from the optical element of the modulator.

Abstract: An improved hinge (12) for a micro-mechanical device (10). The hinge is fabricated from alternating layers (12a, 12b) of different materials. A first material is selected on the basis of its amenability to fabrication processes and a second material is chosen for its strength, or some other desired characteristic, relative to the first material.

Abstract: A light beam condensing apparatus is provided for introducing a condensing spot of a laser beam onto an optical recording medium such as optical disks, and a method of driving the optical recording medium by applying the apparatus. The apparatus can include a modulator disposed between a collimate lens and an objective lens. The modulator can be mechanically or electrically driven to control and vary the amplitude or phase of a collimate beam. Further, the modulator can be switched according to an operational mode of a drive unit or a type of a recording medium so as to provide a desired condensing spot shape.

Abstract: A concentric optical system usable as either an imaging optical system or an ocular optical system, which enables a clear image to be obtained at a field angle of up to about 90.degree. and with a pupil diameter of up to about 10 millimeters with substantially no chromatic aberration. The concentric optical system includes a first optical component having a first semitransparent reflecting surface (2), and a second optical component having a second semitransparent reflecting surface (3). The first and second semitransparent reflecting surfaces (2 and 3) have respective centers of curvature disposed at approximately the same position (1). The first and second optical components are different in dispersion from each other.

Abstract: A projection lens unit includes, in accordance with the order of disposition from a screen side, a first lens group including a positive meniscus lens, a second lens group including a double convex lens, and a third lens group which corrects curvature of field, wherein the third lens group has two concave lenses. A projection lens unit includes, in accordance with the order of disposition from a screen side, a first lens having a positive meniscus form, a second lens having a negative meniscus form, a third lens which is double-convex lens having a light gathering function, a fourth lens which is disposed near the third lens and is a double-convex lens having a positive power, a fifth lens provided at its central portion with a convex surface directed to a screen and provided at its peripheral portion with a concave portion directed to the screen, and a sixth lens having a concave surface directed to the screen, wherein each of the second, fourth and fifth lenses has at least one aspherical surface.

Abstract: A triplet lens system comprising, in order from the object side, a first positive meniscus lens component having a convex surface on the object side, a second biconcave lens component, a third biconvex lens component and a stop; and configured so as to correct aspherical aberration and coma at the same time by using at least one aspherical surface on the second and the third lens components.

Abstract: An optical streak camera includes an optical collimator, an all optical deflector, a detector and a display.

Abstract: A direct-view display comprising an array of micro-mechanical modulators is disclosed, he modulator used to form the display comprises a suspended, vertically moving membrane and a substrate. The device functions based on optical interference effects between the membrane and the substrate which cause the modulator to either substantially reflect or absorb an optical signal. The interference effects are a function of the size of the air gap between the membrane and substrate, which varies as the membrane moves. The membrane moves in response to a data signal, representative of an image, delivered to the modulator. The display generates an image based on the pattern of light and dark sections of the display corresponding to the reflectivity of each modulator at a given point in time.

Abstract: A zoom lens includes a first lens group which is fixed during zooming operation and has a positive refracting power, a second lens group which comprises a first movable lens subgroup having a negative refracting power, a second movable lens subgroup having a negative refracting power and a third movable lens subgroup having a negative refracting power or a positive refracting power. The lens groups and the movable lens subgroups are arranged in the above-described order from the object side. The second movable lens subgroup is moved toward an image along an optical axis upon zooming operation from a wide angle side end position toward a tele-side end position, and the first movable lens subgroup and the second movable lens subgroup are relatively close to each other at the wide angle side end position and at the tele-side end position and are distant from each other at an intermediate zooming position.

Abstract: A retrofocus type wide-angle lens for achieving a highly stable imaging performance and a reduction in spherical aberrations, astigmatism, and coma, while allowing for a large aperture and a large wide angle of view. The retrofocus type wide-angle lens has, in the following order from an object side, a first lens group having a negative refracting power and being fixed in a focusing operation and a second lens group having a positive refracting power and being moved in the focusing operation. The first lens group has, in the following order from the object side, a first unit with a negative refracting power and a second unit having a positive refracting power. The second lens group has, in the following order from the object side, a first unit with a negative refracting power, a second unit with a positive refracting power, a third unit with a negative refracting power and a fourth unit with a positive refracting power.

Abstract: An objective lens system comprising at least one diffractive optical element, having a high magnification and a large numerical aperture, and capable of favorably correcting aberrations, in particular, longitudinal chromatic aberration and lateral chromatic aberration.

Abstract: A spatial light modulator (40, 70, 80) operable in the analog mode for light beam steering or scanning applications. A deflectable mirror (42, 72) is supported by a torsion hinge (44) along a torsion axis. A plurality of flexure hinges (48) are provided to support the corners of the mirror (42, 72) and provide a restoration force. The combination of the torsion hinges and the flexure hinges realizes a deflectable pixel that is operable in the linear range for a large range of address voltages. The flexure hinges also maintain a flat undeflected state when no address voltage is applied, and prevent the pixel from collapsing. The pixel may be reinforced, such as about its perimeter (74) to ensure mirror flatness and prevent warping, even during extreme deflections of the mirror. The pixel is electrostatically deflected by applying an address voltage to an underlying address electrode (60).

Abstract: A zoom lens system comprising, in order from the object side, a first lens unit which has a positive refractive power and is to be kept stationary for zooming the lens system, a second lens unit which has a negative refractive power and is movable for zooming said lens system, and a third lens unit which has a positive refractive power and is to be kept stationary for zooming the lens system: the second lens unit consisting of a front subunit having a negative refractive power and a rear subunit having a negative refractive power. The zoom lens system is configured so as to corect a deviation of an image location by varying, during zooming, an airspace reserved between the front subinit and the rear subunit.

Abstract: An apochromatic grism (42) includes a first prism (48) with a second prism (50) disposed adjacent to it. A grating (44) is adjacent to the front surface of the first prism (48) and the Abbe number and dispersion coefficient of the grating are chosen such that the primary and secondary angular spread for a given spectral band is approximately zero. The apochromatic grism is a simple and compact device with minimal amounts of residual chromatic and anamorphic aberrations.

Abstract: A projection lens for a projection television is made to match different inch sizes of the screen. The kind of coolant material constituting a liquid lens which is attached to the front surface of a projection tube is changed or the coolant is constructed by a plurality of kinds of liquid materials and a mixing ratio of the coolant materials is changed, thereby matching to the inch size of each screen is made.

Abstract: A camera lens system consists of first to third lens elements arranged in this order from the object side. The first lens element is a meniscus lens having a weak refractive power and concave toward the object side, the second lens element is a lens having a positive refractive power and the third lens element is a lens having a negative refractive power. A stop or an assumed stop is disposed close to the object side end of the lens system or on the object side of the same formula .nu..sub.3 .ltoreq.40 is satisfied wherein .nu..sub.3 represents the Abbe's number of the third lens element.

Abstract: There is disclosed an imaging system forming a pseudoscopic image in focus throughout extended depth of field comprising an input relay lens array, a double integral microlens screen having a median plane on to which the input lens array images an object scene and, on the opposite side of the screen and the same distance therefrom as the input array, an output relay lens array similar to the input lens array.

Abstract: A toroidal lens has a first surface comprised of a convex curve rotated about a central axis and a second surface comprised of a concave curve rotated about the central axis. The toroidal lens receives a radiation beam and produces an annular or halo shaped radiation beam. This resulting annular beam is focussed by a focussing lens to a reduced focus spot size without sacrificing depth of focus.

Abstract: A zoom lens of the rear focus type is disclosed comprising, from front to rear, a first lens unit of positive refractive power, a second lens unit of negative refractive power, a third lens unit of positive refractive power and a fourth lens unit of positive refractive power, the second and fourth lens units axially moving to effect zooming, and the fourth lens unit axially moving to effect focusing. The third lens unit includes at least one positive lens at a front position and a negative lens of meniscus form concave toward the image side at a rearmost position. The fourth lens unit includes one negative lens and two positive lenses. The focal lengths f3 and f4 of the third and fourth lens units, respectively, satisfy the following condition:0.73<f3/f4<1.00.