Abstract: Apparatus suitable for transforming a radiation beam so that it can exit with a predetermined alteration. The apparatus includes a first variably diffractive radiation element for transforming a characteristic of the radiation beam from an original state; a second radiation element juxtaposed to the first radiation element for transforming the same characteristic in a complementary way; and, means for physically deforming the first variably diffractive radiation element so that its diffracting pattern can change in a known way.

Abstract: A protective composite thin film coating structure is disclosed which provides ultraviolet (UV)-protection to polymer components used in low earth orbit (LEO) environments. The structure protects such components from physical and optical degradation due to exposure to ultraviolet radiation and oxygen, in particular atomic oxygen.

Abstract: Security devices which are difficult to reproduce include a grid screen metallization pattern. The grid screen metallization pattern may be laid down over a hologram or diffraction grating formed as a surface relief pattern on a substrate, to form a visually identifiable, semi-transparent security device. Additionally, the metallization pattern may include resonant structures in which information about the security device is encoded. In some embodiments of these security devices, the metallization pattern is disposed in accurate registration with the underlying hologram or diffraction grating. These security devices are made by methods which include printing an oil pattern on the substrate. Areas on which oil is deposited do not receive metal during a metallization step. Since these methods do not use caustics, metallization patterns including features which would otherwise trap and hold caustics are possible.

Abstract: The sight comprises a support adapted for mounting onto an instrument to be aimed at a target, an optical device mounted onto the support for creating an image including a first sighting mark at a first finite distance with respect to the optical device, and a device mounted on to the support for providing a second sighting mark at a finite distance with respect to the first sighting mark. The instrument is aimed at the target by aligning the sighting marks. Since at least the first sighting mark is an image, its position can be chosen to improve the accuracy of aiming by alignment of the marks without having to physically accommodate the first mark.

Abstract: A method of producing a holographic optical element which is capable of imparting complex corrections to the holographic optical element and of effecting the exposure using a short optical path permitting little disturbance to be infiltrated. A correction holographic optical element 13 for correcting the characteristics of the holographic optical element is disposed in at least one of the optical paths of an object beam 35 and a reference beam 36 that fall on a photosensitive material 11. The object beam 35 may be one obtained by reflecting the reference beam 36 by a reflection-type holographic optical element such as a reflection-type master holographic optical element 12. In the case of a holographic optical element used for the head-up display, the correction holographic optical element 13 may be given characteristics for correcting the curvature of the windshield or characteristics for correcting color aberration.

Abstract: The apparatus for providing an autostereoscopic view of three dimensional structures includes a display device including several different two-dimensional views of a three-dimensional structure, optical image forming devices arranged in front of the display device and a screen for forming images in an observation plane from light rays issuing from the optical image forming devices so that images of the two-dimensional views appear in respective observation zones in the observation plane. The optical image forming devices (AE) are provided with aperture stops and include a device for overlapping the observation zones (BZ6) to form overlapping zones (UZ6). The aperture stops are provided with edge regions having a continuous transitional decrease of light transmission from complete transmission at their edges to zero transmission at a predetermined distance from their edges.

Abstract: A method of holographic recording in a photorefractive medium wherein stored holograms may be retrieved with maximum signal-to noise ratio (SNR) is disclosed. A plurality of servo blocks containing position feedback information is recorded in the crystal and made non-erasable by heating the crystal. The servo blocks are recorded at specific increments, either angular or frequency, depending whether wavelength or angular multiplexing is applied, and each servo block is defined by one of five patterns. Data pages are then recorded at positions or wavelengths enabling each data page to be subsequently reconstructed with servo patterns which provide position feedback information. The method of recording data pages and servo blocks is consistent with conventional practices. In addition, the recording system also includes components (e.g.

Abstract: An achromatic optical system that preferably includes a light source for emitting light therefrom, an achromatic optical element positioned to receive light emitted from the light source, and an optical detector positioned to receive and detect light passing through the optical element. The achromatic optical element preferably includes a substrate having opposing sides, a first computer generated hologram positioned on one side of the substrate and adapted to receive light emitted from the light source, and a second computer generated hologram positionally aligned on the opposite side of the substrate and adapted to receive light passing through the substrate from the first hologram at a predetermined location thereon.

Abstract: An optical system for the two- and three-dimensional representation of information by the use of transmission displays for the computer and video technology, for head-up displays for aviation and space flight, in advertising and presentation, in medical engineering, in the field of virtual reality and in other fields comprises: a light-source arrangement with at least one point or line source of light, a collimating optics for rendering the light parallel, a transmission display, a prism mask with prisms in a matrix arrangement, the prisms having two different prism angles, a field lens as a focussing optics as well as a phase mask. The image can be well seen by several viewers without any aid, the viewers being able to move laterally and vertically as they like. It is possible to offer two different TV programs to two or more persons at the same time. If all the viewers watch the same program, no sequential switching-over is necessary.

Abstract: The invention provides an imaging spectrometer that provides a wide field-of-view camera and spectrometer for spectral imaging of a large two-dimensional area of the Earth's surface from an orbiting satellite or airplane. The wide field-of-view camera fore-optics includes spherical optical elements arranged monocentrically. The spectrometer includes an all-reflective coupling design that transfers the curved optical image to one or more compact imaging spectrometers. The spectrometers preferably comprise a spherical convex holographic grating and associated reflective optics for dispersing a collimated optical beam into its spectral components and focusing the spectral image onto a planar detector array. The instrument described herein is designed to operate in a "pushbroom" fashion, that is, the forward motion of the satellite or airplane generates the spatial dimension of the resulting image.

Abstract: To improve non-flammability, there is provided a reflective screen for a liquid crystal projector or display in an aircraft. An antireflective member holding an antireflective function on its surface is provided on a top surface of a polarizing film through urethane resin system adhesive, and a reflective member is provided on a bottom surface of the polarizing film through an acrylic resin system pressure sensitive adhesive.

Abstract: A portable emission microscope for analyzing failures in an integrated circuit chip while the chip is contained within a wafer sorter. A base for the microscope is placed over an opening in the wafer sorter. A translational apparatus is attached to the base for lowering a charge coupled device camera into an opening in the wafer sorter. A compact housing containing microscope optics is coupled to the camera. Also, a flexible rubber boot is coupled to the microscope optics for shielding extraneous light from entering the camera. A vibration reducing apparatus is coupled to the microscope optics for preventing movement of the camera relative to the chip. The vibration reducing apparatus fits within the rubber boot and is a rigid, hollow cylinder having an adjustable length. The microscope optics view the chip through the cylinder.

Abstract: A holographic optical filter separates broadband electromagnetic radiation into spectral components corresponding to different spectral regions and then images this radiation onto pixels of a display. It includes two layers of holographic optical elements that are sensitive to each of these spectral regions. The holographic optical elements generally transmit radiation outside of their bandpass but can diffract radiation falling within it. The filter is well suited for display applications and can be used in either a reflective or transmissive mode.

Abstract: Reflector having a composite reflectivity enhancing layer as reflecting surface layer on a reflector body where the said composite has a sandwich structure with an aluminum layer facing the reflector body, an outer layer, the HI-layer, with a refractive index n.sub.2 facing the radiation to be reflected, and an intermediate aluminum oxide layer, the LI-layer, with a refractive index n.sub.1 which is smaller than n.sub.2. The LI-layer is a transparent and pore-free barrier layer produced by anodic oxidation of the aluminum layer and having a dielectric constant .epsilon..sub.1 of 6 to 10.5 at 20.degree. C. and the optical layer thickness d.sub.opt.1 of the LI-layer and d.sub.opt.2 of the HI-layer are such thatd.sub.opt,i =d.sub.i.n.sub.i =l.sub.i..lambda./4.+-.10 nm, i=1, 2where d.sub.1 represents the thickness of the LI-layer in nm, d.sub.2 the thickness of the HI-layer in nm, .lambda. the average wave length in nm of the light striking the reflector surface and l.sub.1, l.sub.2, uneven natural numbers.

Abstract: Cascaded diffraction grated pairs are employed to form submicron gratings and other patterns in various types of devices using photolithographic, UV exposure and other techniques. Cascaded grating pairs are formed in masks which are positioned between a source of radiation and the device or substrate in which a grating is to be formed. The interaction of the diffracted beams generated by each diffraction grating in a cascade grating pair results in the device grating having a period which is substantially smaller than that of either of the gratings in the cascaded grating pair. As a result, gratings with substantially smaller periods than were previously obtainable can now be achieved using conventional fabrication techniques. To eliminate sensitivity to background exposure in photolithographic fabrication applications, a mask is employed in which first and second cascaded grating pairs are separated from one another by an opaque region that acts as a spatial filter.

Abstract: A polarization converter for polarizing a light beam by converting all light waves to the same orientation comprises 1) a first beam dividing matrix of refractory material for dividing a single, large light beam into smaller sub-beam 2) a second beam focusing matrix for polarizing select portions of the sub-beams, and 3) a series of narrow and shallow polarizing cells. The second beam focusing matrix further comprises a plurality of concave lenses for redirecting each sub-beam and quarter wave retarders disposed in alignment with, and adjacent to, the reflective side of an equal plurality of mirror segments. The polarizing cells include either a first beamsplitter or a second beamsplitter, where the first beamsplitters and second beamsplitters are disposed in opposing diagonal fashion and in an alternating manner.

Abstract: This disclosure is concerned with a lenticular or barrier strip picture with changeable scenes wherein a trimmed lenticular screen or a barrier strip plate is used to view a composite image. On a conventional lenticular picture, the focal plane of the lenticules on the lenticular screen coincides with the backside of the lenticular screen and, therefore, the composite image must be placed in contact with the backside of the lenticular screen. On the lenticular picture according to the present invention, the thickness of the lenticular screen is trimmed such that the focal plane of the lenticules is located further away from the backside of the lenticular screen. In order that a composite image can produce a properly focused composing scene when viewed through the trimmed lenticular screen, it must be positioned on the focal plane of the lenticules away from the backside of the screen, leaving an airgap therebetween. With in such an airgap, a holding plate is disposed to hold down said composite image.

Abstract: An optical system for a real image type view finder having an objective lens system and an ocular lens system, including a first deflector and a second deflector. The first deflector has a first reflection surface which reflects on-axis light, incident thereupon along an optical axis of the objective lens system, towards an optical axis of the ocular lens system. The second deflector has an incident surface upon which light, reflected by the first deflector, is made incident, and second and third reflection surface to internally reflect that light incident upon the incident surface, before emitting the light through an exit surface toward the ocular lens system. The on-axis light incident upon the first deflector and the light reflected by the first deflector defines an acute angle therebetween. The second deflector satisfies the following relationships:90.degree.<.theta.<120.degree.90.degree.<.psi.<120.degree.wherein ".theta.

Abstract: A holographic stereogram which includes a plurality of element holograms and which reproduces a stereoscopic image by irradiation of coherent light, wherein each element hologram is loaded with a modulation value (pattern) corresponding to the stereoscopic image, the modulation value being a one-dimensional or two-dimensional transform coefficient obtained by one-dimensional or two-dimensional cosine transform or discrete cosine transform of the distribution of the intensity of diffraction light expressing the stereoscopic image, enabling simplification of the drive system of the display device displaying the stereoscopic image and reproduction of the original stereoscopic image much more faithfully.

Abstract: A two-dimensional diffraction grating (5, 14) has a plurality of grating elements arranged in two directions (X, Y) different from each other. The grating elements in one of the directions (X, Y) have a substantially uniform grating height (h) when viewed in an arbitrarily chosen section along such one of the directions (X, Y) and, also, the grating elements in the other of the directions (X, Y) have a substantially uniform grating height (h) when viewed in an arbitrarily chosen section along the other of the directions (X, Y). An image display device includes an image display unit (4) including a plurality of pixels (10) patterned in a dot matrix in two dimensions and having a path (2) of travel of imagewise rays of light, and the two-dimensional diffraction grating (5) disposed on the path (2) of travel of the imagewise rays of light leading from the image display unit (4).