Abstract: Bow can be minimized by an auxiliary grating in a post deflection path of the diffracted beam from the hologon which is disposed in non-parallel relationship to the plane of rotation of the hologon. The ellipticity of the spot which generates the scan line and intensity variation in the scan beam can be minimized by using a dispersive element, preferably a prism, between the hologon and the bow compensation grating with its dispersion in a direction opposite to the direction of the dispersion of the hologon and of the auxiliary grating. Another grating before the hologon can be used to correct for wavelength shift induced cross-scan error associated with the dispersion in the hologon and a bow compensation grating following the hologon.

Abstract: A biocular display system (19) for generating a virtual image (30) of a visible display (20). A diffractive binary optical element (22) is used to create the virtual image (30). The binary optical element (22) contains magnifying power to increase the size of the virtual image (30). Also, the binary optical element (22) contains prismatic power to displace the virtual image (30) away from the display (20). Multiple displays (40), (42) may be viewed by employing a binary optical element (34) having multiple diffractive orders.

Abstract: A diagnostic test for glaucoma, which can detect the early stages of this disease, uses a pattern electroretinogram of a subject to assess any reduction of the density of M.sub.y ganglion cells in a part of the subject's retina. The visual field of the eye of the subject is divided into a number of zones, and a respective visual stimulus signal is applied to each zone. The visual stimulus signals are generated in accordance with data obtained from determinations of the critical spatial frequency (Nyquist frequency) of persons with normal vision, obtained from observations of the "aliasing" phenomenon. Typical visual stimulus signals are grating patterns, with the contrast of the signal applied to each zone modulated with a different temporal frequency in the range of from 10 Hz to 45 Hz. Any differences between the electroretinogram response component for an individual zone and the expected response component for that zone indicates a change in the M.sub.

Abstract: A corneal topographer including a directional light source, a CCD and a positioning stage all controlled by a computer for automatically centering and focusing the corneal image onto the CCD. The computer receives video signals from the CCD representing the corneal image, which is digitized and displayed on a real-time basis on a monitor screen. A reflection of the directional light source is positioned to align in the center of the corneal image. An operator moves an optics head to place the corneal image on the monitor screen, roughly focuses the image, and then commands the computer to take over. The computer calculates the distance between the image of the directional light source and the center of the CCD, and activates the positioning stage to move the directional light source image to the center. The positioning stage is moved within a focusing range, where several positions and corresponding intensity characteristics of the directional light source image are tabulated.

Abstract: A combination extended natural eyeglasses and corrective eye magnifier comprising a frame, having a front, and having a pair of lens mounting portions separated by a bridge portion. The bridge portion having a light bulb, for illuminating an area in front of the frame. The lens mounting portions having a front slot, a rear slot, and a window having a plurality of small holes between the front slot and rear slot. A magnifying lens can be placed in each the front slot and rear slot. Two temple bows, each having a curved earpiece, are attached to the frame, and extend rearwardly therefrom, the curved earpiece being at an end of each temple bow opposite the frame. The temple bows are attached to the frame with a hinge mechanism, so that they can enter a position where they extend in front of the frame for supporting the frame on a horizontal surface in front of the frame.

Abstract: An optical instrument for indirectly observing an object includes a first lens system for producing a first image of the object, and an adjustable second lens system for producing a second image of the object. The second lens system is continuously adjustable between a first position wherein the second image has maximum magnification and/or a minimum area of view, and a second position wherein the second image is of a minimum magnification and/or a maximum area of view. In one aspect of the invention, the second lens system is a zoom lens system having two substantially fixed conjugate planes. In another aspect of the invention, the instrument defines a folded optical path through the lens systems which includes a generally U-shaped portion so as, in use, to reduce the separation of the observer and the observed object.

Abstract: An indicia display device for eyeglasses or the like includes a display pennant, an elongated support and a fastener for coupling with an eyeglass templepiece. The pennant is mounted in upright position, atop the support and above and beyond the peripheral vision of the wearer. The fastener includes a pair of slots for accepting the templepiece of a pair of glasses and for permitting slidable movement of the device along the length of the templepiece until the pennant is correctly positioned.The generally planar support provides an additional surface for display of indicia. In certain preferred forms, the device is of unitary construction with a pair of disposable sunglasses.

Abstract: A method of writing plane holographic gratings Bragg-matched for reflection in the infrared in a photorefractive material using shorter wavelength light through a face perpendicular to the grating planes. The writing beam wavelength is selected to be within the photorefractive sensitivity range of the crystal and the angles are chosen relative to the wavelength to define a reflection grating with a period such that counter-propagating reflection occurs at the desired IR wavelength. For reflection gratings at different wavelengths, either the transmission or the reflection mode geometry may be used. In the transmission mode, the writing beams are incident on the same side face while in the reflection made the writing is on opposite faces in an off-axis (non-counter-propagating) configuration. Anti-reflection coatings of the appropriate wavelengths are used on the crystal surfaces to reduce reflection losses and improve the diffraction efficiency of the grating.

Abstract: An elastic hinge for a pair of spectacles is made, on the one hand, of a front-hinge element (10) securely fixed to a side lug (6) of the front part; and, on the other hand, of a side-hinge element (20) connected by elastic biasing means (12, 30, 40, 44) at the end of the side arm (8). The outer edge of the end (9) of the side arm (8) bears against a fixed heel (7) extending from the lug (6) or integral with the front-hinge element. This heel (7) extends beyond the axis (15) of the hinge by a distance (d) greater than 0.3 millimeters. Moreover, the side-hinge element (20) has, in its face directed towards the side arm, a recessed edge (32) which after rotation through a desired maximum angle (.theta.), comes to bear against the abutment-forming inside angled edge (5) of the heel (7).

Abstract: An optical system of an optical disc apparatus is disclosed for converging and projecting a bundle of rays emitted from a light source onto an optical disc. The optical system includes a collimating lens which collimates the bundle of rays emitted from the light source, two anamorphic prisms for shaping the cross section of the collimated bundle of rays transmitted through the collimating lens, and an objective lens which converges the bundle of rays shaped by the anamorphic prisms onto the optical disc. At least one of the anamorphic prisms is detachably mounted to an immovable body portion of the optical system.

Abstract: An ophthalmologic apparatus for repeated optical or photometric examination of the fundus or another portion of a patient's eye has an illuminating unit with a light source for a microscope. The optical axis of the microscope can be repeatedly moved to one and the same position relative to a beam of radiation issuing from the center of curvature of the external surface of the cornea in a patient's eye with assistance from a positive field lens which is adjustable with the microscope and acts not unlike an ophthalmoscopic lens for indirect ophthalmoscopy. The lens projects for the microscope a real intermediate image of the selected portion of a patient's eye in an intermediate plane adjacent that focal point of the lens which is remote from the patient's eye. An illuminated or radiation emitting marker is provided at that side of the intermediate plane which faces away from the lens and close to the optical axis of the microscope.

Abstract: The present invention consists of a device which removeably secures a standard set of earplugs to a pair of eyeglasses, preferably safety glasses, by double looping a standard cord with a pair of cord adjusters. A pair of double looped elastomeric temple securing means hold both a loop of the cord through one of each of their loops and an eyeglass temple piece through the other of their loops. The tips of the cord are provided with an annular binding surface which may be inserted into the end of a standard earplug cavity which is cylindrical in configuration and which secures the earplug to the cord tip by frictional engagement therewith.

Abstract: A foldable elastic temple for spectacles having a front half temple elastically combined with a lens frame by means of an elastic assembly consisting of a connector, a socket, a spring and a bolt, the elastic assembly fitted in a front chamber provided in a front end portion of the front temple to provide the front half temple with elasticity to be stretched outward for wearing on any size of a face, and a rear half temple combined pivotally with the front half temple to allow the front half temple folded on the rear half temple for minimizing the length of the temple in putting away.

Abstract: An eye refractometer has an illumination system for irradiating a fundus of an examined eye with measurement light, and a light receiving system for receiving a light beam from the fundus of the examined eye irradiated with the measurement light. The illumination system can change the measurement light between visible light and infrared light, and can emit the visible light in a flashing manner. Eye refraction information of the examined eye is detected on the basis of light reception through the light receiving system, and the difference between detection values of the eye refraction information before and after a change of the measurement light.

Abstract: Eyewear frames are provided having a pair of interchangeable lenses wherein each lens has a pair of oppositely disposed sidewardly extending projections. The distal projections fit within recess areas on the distal ends of the top frame and proximate projections are locked into place over the nose area by a movable nose bridge.

Abstract: An examination apparatus for examining an object having a spheroidal reflecting surface provides a first index projecting optical system for projecting a first measuring index onto the object to be examined at a designated angle, a second index projecting optical system for projecting a second measuring index having a different optical distance from the first index onto the object at the designated angle, so that each reflected images of the first and second measuring index have a designated image height relationship therebetween when the object is placed at a designated working distance, and respective image height of reflected images of the first and second measuring index are detected by a detecting optical system with a photoelectric conversion apparatus, whereby whether the working distance between the object and the apparatus is right or not is judged by processing a signal detected by the photoelectric conversion apparatus.

Abstract: In an eyeglass frame each lens is gripped between a relatively rigid half-rim and a filament. The half-rim is fixed to a tenon in which is formed a cavity opening through an orifice forming a keyhole slot. The filament includes a knot retained in the cavity by the keyhole slot.

Abstract: A retainer for securing a nose pad on an eyeglasses frame, the retainer being composed of a flat, one-piece pad arm having a receiving opening in the form of an elongated hole, and a retaining element of plastic secured to the nose pad, the retaining element having a constriction and being receivable in the receiving opening of the pad arm to be locked in the receiving opening by engagement of the constriction in the opening. The pad arm is a bilaterally symmetrical structure having a first end in which the opening is formed, is made of material which extends continuously around the opening and is substantially inelastic around the opening. The opening cross section of the elongated hole is selected and the retaining element is formed such that when the constriction engages in the receiving opening, a transition surface of the retaining element is engageable with the pad arm for allowing the retaining element and the nose pad to be pivotable and tiltable relative to the pad arm.

Abstract: An optical scanner unit for scanning a document includes a laser unit for emitting a laser beam used for scanning the document, an optical system in which the laser beam emitted from the laser unit travels to the document and a reflection light beam obtained by reflection of the laser beam on the document can turn back through the optical system, the optical system having a scanning device for moving the laser beam which passes through the optical system so that a two dimensional scanning of the document is carried out by the light beam, and an optical sensor for detecting the reflection light beam turning back through the optical system, wherein an image formed on the document is read based on results obtained by the optical sensor.

Abstract: Upper lens formed of a portion of a sphere having radius R.sub.2 and lower lens formed of a portion of a sphere having radius R.sub.1 are manufactured integrally by molding for forming the lens of eyeglasses Radii R.sub.1 and R.sub.2 are slightly different from each other, so that the front view comes into eyes through lower lens when the user is in a normal posture, while the front view comes into eyes through upper lens when the user bends forward.