Abstract: A lens barrel of the present invention includes a fixed frame, a plurality of lens groups disposed on the inner circumference of the fixed frame movably along an optical axis direction with respect to the fixed frame, at least three lens holding frames for holding at least one lens group of a plurality of the lens groups, a cam frame having bottomed cam grooves to be coupled with the inner circumference of the fixed frame through cams, bottomed cam grooves across each other to be coupled with the lens holding frames through cams and a bottomed cam groove which is discontinued on one end surface and continued from the other end surface, a key member for regulating the rotation of the lens holding frames about an optical axis with respect to the fixed frame as well as reinforcing the strength of the entire lens barrel, a cam mechanism interposed between the cam frame and the lens holding frames for moving the lens holding frames along the optical axis direction by the rotation of the cam frame about the optical

Abstract: An improved electrochromic device, the device incorporating an electrochromic medium that comprises at least three electroactive materials having absorption spectra that add together such that the color of the electrochromic medium can be pre-selected by individually choosing the concentrations of the at least three electroactive materials. The electrochromic medium generally maintains the pre-selected perceived color throughout its normal range of voltages when used in an electrochromic device. The at least three electroactive materials include at least one electrochemically reducible material (cathodic material), at least one electrochemically oxidizable material (anodic material) and at least one additional electroactive material which may be either an anodic or cathodic material. Thus, there are always three electroactive materials present in the medium, with at least two either being anodic or cathodic materials.

Abstract: An electro-acoustic transducer is attached to a block of optical material, and forms an acoustic standing wave in the block; the acoustic standing wave periodically changes the refractive index of the optical material, and forms high refractive index portions alternated with low refractive index portions; and the high refractive index portions serve as optical wave guides, and the electro-acoustic transducer easily produces the optical wave guide in the block.

Abstract: The diffractive optical modulator of the invention includes: a plate having a portion functioning as a first electrode; a spacer layer formed on the plate; and a grating consisting of a plurality of beams having a portion functioning as a second electrode, both ends of the beams being supported on the spacer layer. In the diffractive optical modulator, by adjusting a voltage applied between the first electrode and the second electrode, a distance between the beams and the plate is varied, thereby controlling the diffraction efficiency. An insulating layer is further provided between the plate and the plurality of beams.

Abstract: An optical beam steering device for steering a beam of light includes a first window having a common electrode, a second window having a plurality of control electrodes, and a layer of electro-optical material intermediate the first and second windows. The common electrode, the control electrodes, and the electro-optical material form an array of phase shifters within the optical array. Each phase shifter has a width substantially greater than a wavelength of the beam of light. Also included is a means for establishing an effective position of the phase shifters so that a single beam of light of peak intensity exits the optical array where the single beam of light is steerable through a predetermined angle.

Abstract: An improved electrochromic rearview mirror for motor vehicles, the mirror incorporating thin front and rear spaced glass elements having a thickness ranging from about 0.5 to about 1.5. A layer of transparent conductive material is placed onto the mirror's second surface, and either another layer of transparent conductive material or a combined reflector/electrode is placed onto the mirror's third surface. A chamber, defined by the layers on the interior surfaces of the front and rear glass elements and a peripheral sealing member, contains a free-standing gel comprising a solvent and a crosslinked polymer matrix. The chamber further contains at least one electrochromic material in solution with the solvent and interspersed in the crosslinked polymer matrix.

Abstract: A counterelectrode for a smart window contains a transparent substrate and a linear electrically conductive material formed on a surface of the transparent substrate. The electrically conductive material has a surface area of not less than 10 m.sup.2 /g and electrical conductivity of not less than 10.sup.-6 .OMEGA..sup.-1 .multidot.cm.sup.-1 at 25.degree. C. A smart window contains an electrochromic electrode having a layer of an electrochromic material formed on its surface, and a layer of an electrolyte arranged between the counterelectrode and the electrochromic electrode and in contact with the layer of the electrochromic material.

Abstract: A lens barrel with a stationary frame fixed relative to a camera body; a flare diaphragm movable in a direction of an optical axis for cutting off harmful incident light; an urging spring urging the flare diaphragm in the direction of the optical axis; a third group frame including a protruding portion which is driven into abutting contact with the flare diaphragm to restrict a position of the flare diaphragm in the direction of the optical axis, the third group frame being moved in the direction of the optical axis; and, a supporting shaft rigidly positioned on the stationary frame. The supporting shaft guides the movable flare diaphragm in the direction of the optical axis, while being snugly fitted to the flare diaphragm. In addition, the supporting shaft includes a stepped front portion for restricting such movement of the flare diaphragm to a predetermined position.

Abstract: An optical apparatus includes a first lens for zooming, a second lens which is arranged in rear of the first lens on an optical axis to correct a shift of a focal plane caused by a motion of the first lens, a vibration wave motor arranged to serve as a drive source for the second lens, and a decision circuit which decides a driving direction and a driving speed of the vibration wave motor by using at least information on the positions of the first and second lenses.

Abstract: The diffractive optical modulator of the invention includes: a plate having a portion functioning as a first electrode; a spacer layer formed on the plate; and a grating consisting of a plurality of beams having a portion functioning as a second electrode, both ends of the beams being supported on the spacer layer. In the diffractive optical modulator, by adjusting a voltage applied between the first electrode and the second electrode, a distance between the beams and the plate is varied, thereby controlling the diffraction efficiency. An insulating layer is further provided between the plate and the plurality of beams.

Abstract: A beam converting optical system is provided which is easy to position the optical elements, which has a comparatively short total length, and which has good aberration correction. A beam converting optical system converts light beams with an oval cross-sectional shape into parallel light beams with a substantially circular cross-sectional shape. A converting lens is provided which has at least one surface that is cylindrical. The horizontal cross section of the cylindrical surface of the converting lens is essentially non-circular. The converting lens may consist of two similar elliptic cylinder surfaces. The two ellipses are of the shape of a horizontal cross section of the two elliptic cylinder surfaces and have the same focal point.

Abstract: The present invention relates to electrochromic polymeric solid films, manufacturing electrochromic devices using such solid films and processes for making such solid films and devices. The electrochromic polymeric solid films of the present invention exhibit beneficial properties and characteristics, especially when compared to known electrochromic media. The electrochromic polymeric solid films are transformed in situ from a low viscosity electrochromic monomer composition by exposure to electromagnetic radiation, and in so doing minimum shrinkage occurs. The electrochromic polymeric solid films of the present invention also perform well under prolonged coloration, outdoor weathering and all-climate exposure, and provide an inherent safety aspect not known to electrochromic media heretofore.

Abstract: A high-performance, long-focal length macrolens system is provided which is easy-to-operate and is capable of photographing an object at an infinitely far distance and an object at a close distance without changing the overall length of the macrolens system. The system is configured in order from the object side, having:a first lens group G1, which includes a negative lens and has a positive overall refractive power,a second lens group G2, which includes a compound lens and has a negative overall refractive power,a third lens group G3, which includes a compound lens and has a negative overall refractive power, anda fourth lens group G4, which has a positive refractive power, and the system fulfills at least three preselected conditions.

Abstract: An ocular optical system suitable for a head- or face-mounted image display apparatus which is compact, lightweight and satisfactorily corrected for aberrations, and in which no intermediate image is formed. The image display apparatus includes an image display unit (9) and an optical system (10) for projecting a displayed image into an eyeball (7). The optical system (10) is arranged such that light rays which are emitted from the image display unit (9) and enter the eyeball (7) are reflected at least three times by surfaces (12, 13 and 14) having power in backward ray tracing.

Abstract: An optical element and a method capable of electromagnetically inducing transparency in a solid. The optical element includes a solid having a number N of sites characterized by at least three energy levels including a first level higher than a second and a third lower than the second, and an excitation device configured to irradiate the solid with a first light having a wavelength corresponding to the energy difference between the first and the second level, and a second light having a wavelength corresponding to the energy difference between the first and the third level. The solid satisfies .sigma..sub.23 .ltoreq..sigma..sub.12 and .sigma..sub.23 .ltoreq..sigma..sub.13 where .sigma..sub.12, .sigma..sub.13 and .sigma..sub.23 are respectively the standard deviations of the energy differences between the first and second level, between the first and third level, and between the second and third level.

Abstract: A Faraday rotator is formed of a bismuth-substituted iron garnet single crystal film grown by a liquid phase epitaxial method. The single crystal film is represented by a formula: Tb.sub.3-x Bi.sub.x Fe.sub.5-y-z Ga.sub.y Al.sub.z O.sub.12 wherein x has the range 1.1.ltoreq.x.ltoreq.1.5, y+z has the range 0.65.ltoreq.y+z.ltoreq.1.2, and z has the range z.ltoreq.y. The bismuth-substituted rare earth single crystal film is subjected to a magnetization process where the single crystal film is magnetized by an external magnetic field so that the film has a square magnetic hysteresis loop. The external magnetic field has a magnetic field strength of 1,000 Oe or higher and is applied in a direction normal to a surface of the bismuth-substituted rare earth iron garnet single crystal film.

Abstract: An optical modulator for a high power laser transmitter includes a laser source coupled through a phase modulator to a signal modulator. A noise source provides a band limited noise signal to either the laser source or the phase modulator or both. Alternatively, an optical modulator for a high power laser transmitter includes a laser source providing a laser output optical signal and a phase modulator. First and second continuous wave signals at respective first and second frequencies are combined to modulate either the laser source or the phase modulator. The first frequency is different than the second frequency. The laser and phase modulation produces a broadened optical output signal such that the broadened optical output signal is characterized by beat frequencies harmonically related to the first and second frequencies. The modulation bandwidth includes no significant beat frequencies.

Abstract: Incident light 1 is inputted to an electro-absorption-type optical modulator 4 via an optical circulator 2 and a lens 3, and subjected to intensity modulation that corresponds to a modulation signal 8. The optical signal outputted by the electro-absorption-type optical modulator 4 is inputted to a Faraday rotator 6 via a lens 5, and the plane of polarization is rotated 45.degree.. The optical signal transmitted by the Faraday rotator 6 is totally reflected by a totally reflecting mirror 7, inputted for the second time to the Faraday rotator 6, then passed through the lens 5 after the plane of polarization has been rotated 45.degree. by this Faraday rotator 6, and readmitted by the electro-absorption-type optical modulator 4. The output of the electro-absorption-type optical modulator 4 is emitted via the lens 3 and the optical circulator 2. The polarization dependence of insertion loss can be eliminated because the plane of polarization is rotated 90.degree.

Abstract: An apparatus for recording or reproducing information on an information recording surface of an optical information recording medium having a transparent substrate, includes a laser source to emit a light beam having a wavelength of .lambda. nm; and an objective lens to converge the light beam emitted from the laser source on the information recording surface of the optical information recording medium through the transparent substrate. When the light beam is converged through the transparent substrate of the optical information recording medium, a wavefront aberration of the objective lens has a curve which has a step at a numerical aperture (NA), and the following conditions are satisfied,W.sub.1 -W.sub.2 =m.lambda.-.delta.,0<.delta.<0.34.lambda.where W.sub.1 represents a wavefront aberration at a point of the step when the curve is traced from a periphery toward an axis of the lens, W.sub.

Abstract: An apparatus for splitting a light beam into two sub-beams is formed of a stationary light source for generating a light beam, of a first polarization converter and of a deflection unit rotating around the optical axis in which two sub-beams are generated from the light beam. The deflection unit contains a polarization beam splitter, a following, second polarization converter and a reflector that is preferably designed as a prism. An automatic correction of positional offsets of the sub-beams is implemented in the deflection unit since the polarization beam splitter or the deflection unit is tilted and/or the lenses are shifted with adjustment drives. The positional offsets of the sub-beams are measured in their focus plane, and corresponding correction values are transmitted with a transformer to the adjustment drives in the rotating deflection unit.