Abstract: A switchable backlight for a switchable privacy display apparatus comprises a collimated waveguide and an optical turning film comprising first and second arrays of elongate prismatic elements. High image luminance and image visibility is provided for off-axis viewers in a public mode of operation while in a privacy mode of operation visual security level above a perceived privacy threshold may be achieved for off-axis snoopers.

Abstract: Methods and systems that include the generation of a map of modulation values for a spatial light modulator. In which a map representative of a desired curing region is received. Receiving, for each pixel of a spatial light modulator, spatial information representative of an intensity distribution of actinic radiation at a plane of formable material under a template that is guided from the spatial light modulator to the plane of the formable material for curing the formable material under the template. Receiving a dose threshold for the formable material. Generating a map of modulation values for each pixel in the spatial light modulator based on: the dose threshold; the spatial information for all of the pixels; and the map representative of the desired curing region.

Abstract: In one aspect, a hyperspectral image measurement device is provided to include: a main body; an illumination module disposed in the main body and including LEDs having different peak wavelengths to irradiate light to a subject; a camera disposed on the main body and receiving light reflected from the subject to acquire an image of the subject; a barrel having a contact surface contacting the subject, the contact surface located to be spaced apart from the illumination module and the camera module by a predetermined distance; and a reference cover located on the contact surface and including a standard reflection layer for reflecting light irradiated from the illumination module toward the camera module.

Abstract: There are provided a reflecting module for optical image stabilization (OIS) and a camera module including the same. The reflecting module for OIS includes: a housing including an internal space; a movable holder supported in the internal space of the housing by an elastic member; a reflecting member disposed on the movable holder; and a driving part configured to provide driving force to the movable holder so that the movable holder is moved relative to the housing, wherein the elastic member includes a fixed frame fixed to the housing, a movable frame provided in the fixed frame, and a spring connecting the fixed frame and the movable frame to each other and, the movable frame is movable in relation to two axes perpendicular to each other.

Abstract: The present invention is a modular electronic-optical-mechanical apparatus, to be used by observers in combination with a wide variety of optical image sources, for observing, acquiring and sharing the optical imagery of objects, and the audio and sounds derived from observing sessions bi-directionally in real time with audiences both remote and local. The apparatus enables observers who are local or remote from optical image sources to control and acquire optical imagery from optical image sources, where those optical image sources include microscopes, telescopes, IR scopes, spotting scopes, polarimeters, interferometer microscopes, interferometers, rifle scopes, surveillance scopes, drone optics, binoculars, theodolites, autocollimators, alignment telescopes, camera lenses, periscopes, slit lamp bio microscopes and dioptometers.

Abstract: An improvement to an optical assembly that is adapted to accept light from a field of view in front of the optical assembly and create a first inverted image on a first image plane. Further the assembly includes an objective lens, a first prism adapted to receive light from the objective lens and a second prism, adapted to receive light from the first prism and emit light. The improvement is the addition of a negative lens interposed between the first prism and the second prism, thereby reducing the total optical pathway of the optical assembly, relative to a device performing the same optical function and lacking the negative lens.

Abstract: An imaging spectrometer, covering the visible through infrared wavelengths, which disperses the light by a plane diffraction grating behind a wedged optical element. This design uses an achromatic doublet lens with a reflective coating on its convex back surface to produce the spectra on a flat detector. Spatial keystone distortion and spectral smile are controlled to less than one tenth of a pixel over the full wavelength range, facilitating the use of simple retrieval algorithms.

Abstract: It is arranged so that the user of a camera will not experience a sense of incongruity when the camera is switched between an optical viewfinder and an electronic viewfinder. When the electronic viewfinder function is set, the image of a subject captured by a solid-state electronic image sensing device is displayed on the display screen of a liquid crystal device and a viewfinder shutter closes. When the optical viewfinder function is set, the viewfinder shutter opens and the image of the subject is not displayed on the liquid crystal device. At the time of a changeover between the electronic viewfinder function and the electronic viewfinder function, the image of the subject being displayed on the liquid crystal device gradually vanishes, or the image of the subject is gradually displayed on the liquid crystal device, while the opening and closing of the viewfinder shutter is tracked. Sudden darkening and sudden brightening at the time of the viewfinder changeover is prevented.

Abstract: A catadioptric projection objective has a first objective part, defining a first part of the optical axis and imaging an object field to form a first real intermediate image. It also has a second, catadioptric objective part forming a second real intermediate image using the radiation from the first objective part. The second objective part has a concave mirror and defines a second part of the optical axis. A third objective part images the second real intermediate image into the image plane and defines a third part of the optical axis. Folding mirrors deflect the radiation from the object plane towards the concave mirror; and deflect the radiation from the concave mirror towards the image plane. The first part of the optical axis defined by the first objective part is laterally offset from and aligned parallel with the third part of the optical axis.

Abstract: Optical apparatus in which a beam deflector is used to reposition the sight beam from a reflex sight. In one example, an optical apparatus includes a reflex sight configured to produce a collimated reflex sight beam directed along an optical axis, and a beam deflector coupled to an output of the reflex sight and configured to deflect the reflex sight beam by a selected angle of deflection relative to the optical axis to reposition an eyebox of the reflex sight off-axis with respect to the optical axis and remote from the reflex sight. In certain examples, the optical apparatus also includes a telescopic sight, and the beam deflector is configured to deflect the collimated reflex sight beam to overlap the reflex sight beam with the exit pupil of the telescopic sight.

Abstract: There are provided an ocular lens in which aberrations are favorably corrected across a sufficiently wide angle of view and a lens diameter is suppressed from increasing with a sufficient eye relief attained and without a total length being long, and an optical apparatus including the ocular lens. An ocular lens 3 used for an optical apparatus such as a telescope optical system TS includes: in order from an object side, a first lens group G1 including a first lens component G1A having negative refractive power and having a concave surface facing a viewer's eye side, a second lens component G1B in a meniscus shape having a convex surface facing the object side, and a third lens component G1C having positive refractive power; a second lens group G2 having a lens component having a convex surface facing the viewer's eye side; a third lens group G3 having positive refractive power. An object side focal plane of the third lens group G3 is positioned between the second lens group G2 and the third lens group G3.

Abstract: Optical lens attachments and cameras are disclosed. The attachment comprises a coupling mechanism for mating engagement with at least one of a camera and an optical lens. A barrel is coupled at one end to the coupling mechanism. A negative lens unit is coupled to the other end of elongated barrel. A diopter lens is disposed between the barrel and the coupling mechanism. The coupling mechanism, the diopter lens, and the barrel are aligned with an optical axis. Also disclosed is a double swivel optical system, comprising a negative lens unit, a mirror oriented at an angle to the optical axis of the negative lens unit, a roof prism for rotating incident light rays by 90 degrees and inverting an image, a rotation mechanism permitting rotation of the negative lens unit about a vertical axis, an image rotator comprising a prism that can invert an image, the prism disposed within the image rotator, and another rotation mechanism permitting rotation of the roof prism about an optical axis of the image rotator.

Abstract: A brightness tracking system for an optical device includes a first imager for viewing a target of interest, a second imager for viewing the same target of interest, and a photodiode circuit. The photodiode circuit (a) measures brightness levels of the target of interest received from the first imager, and (b) controls output brightness of the second imager, based on the measured brightness levels received from the first imager.

Abstract: An optical scope has at least one optical element which is used to image an object. An optical element is, for example, understood to mean a lens unit, a prism, or a prism system composed of multiple prisms. A lens unit is, for example, understood to mean one single lens or a unit which is composed of at least two lenses. It is provided to make the optical element of glass, namely N-BK7HT, N-SK2HT, F2HT, N-LASF45HT, SF6HT, N-SF6HTultra, N-SF6HT, SF57HTultra, N-SF57HTultra, N-SF57HT, N-LASF9HT and/or N-BAK4HT. The above-named glasses are glasses of the SCHOTT corporation.

Abstract: A transmission-type OLED riflescope with a prism assembly having an ocular lens and an objective lens, wherein the prism assembly has a roof prism, a half pentaprism, an isosceles prism and a spectro-film, and the right end of a laser receiver abuts against the left end of the isosceles prism so that both of the laser receiver and the isosceles prism are located below the axis of the lens cone while the laser transmitter is located above the axis of the lens cone with the laser transmitted from the laser transmitter exiting after being refracted by the objective lens, while a transmission-type OLED display is arranged between the ocular lens and the prism assembly. Functions of the riflescope include observing, aiming, and laser ranging and transmission using the same objective lens. The viewer can also see the objects behind the lens.

Abstract: The invention relates to a telescopic sight with an objective to face a target object to be observed in a working position, an eyepiece to face an observer, a visual observation beam path, an inner tube with an inversion system, means for adjusting the direction of the sight line of the telescopic sight, a rangefinder and with a scope housing, in which are integrated the rangefinder, which has a transmitter for emitting a measurement beam and a receiver for receiving the reflected measurement beam, and arranged in the region of the observation beam path a beam splitter element, which couples the emitted measurement beam into the part of the observation beam path extending toward the objective and/or decouples the received reflected measurement beam from the part of the observation beam path extending toward the objective.

Abstract: A viewing apparatus comprises one or more optical elements, which may be moved in order to redirect light entering the viewing apparatus such that a subject in any part of the field of view may be relocated to the center of the viewed image without moving the viewing apparatus itself. The viewing apparatus further comprises a relay lens group which conditions the light into a quasi-collimated state before it enters the optical elements allowing a more compact device to be produced. The viewing apparatus may additionally include a zoom lens mechanism to enable the viewed image to be enlarged.

Abstract: The disclosure is based on an aiming optical device for a measuring instrument, more particularly for a distance measuring instrument comprising an optical unit, having at least one optical deflection unit and a first optical lens element. It is proposed that the optical deflection unit and the first optical lens element are embodied integrally with one another at least in part.

Abstract: Binoculars have two tubes connected to each other via a folding bridge and an Abbe-König prism system is arranged in each tube and the Abbe-König prism systems are provided for image reversal of respective visual viewing beam paths. Each Abbe-König system includes an isosceles prism and a roof prism adjacent thereto. A laser transmitter (21) in the first tube (3a) and a corresponding laser receiver (22) in the second tube (3b) can be changed in parallel with respect to the distance to each other by means of the folding bridge (37). One of the two prisms (9, 10) of each Abbe-König prism system (6) is configured with a splitter layer (12, 12?, 12?) or is connected via a cement layer for splitting the viewing beam (7) and laser beam (24) into separate beams with the beams (7, 24) running part way in common in the respective tubes (3a, 3b).

Abstract: Provided is an endoscope optical system including first deflecting means that deflects light incident along an incident optical axis in a direction along a first axis perpendicular to the incident optical axis and emits the light; second deflecting means having two reflecting faces that fold back the light emitted from the first deflecting means along a second axis separated from the first axis by a gap; and third deflecting means that deflects the light folded back by the second deflecting means in a direction perpendicular to the first axis and along a plane including the incident optical axis, wherein the first deflecting means is provided so as to be capable of swiveling about the first axis relative to the second deflecting means, and the two reflecting faces of the second deflecting means are disposed to form an obtuse angle therebetween.

Abstract: An optical sight is provided and may include: a housing; at least one prism supported by the housing; an optical device disposed on the prism and including a longitudinal axis; and an illumination device associated with the optical device and operable to supply the prism with light via the optical device by supplying light to the optical device in a direction along the longitudinal axis.

Abstract: An optical sight is provided and may include a housing, at least one optic supported by the housing, and an illumination device associated with the at least one optic that selectively supplies the at least one optic with light. The illumination device may include a first fiber associated with a first light source and a second fiber associated with a second light source. A coupler may join the first fiber and the second fiber and may supply the at least one optic with light from at least one of the first light source and the second light source.

Abstract: Providing a viewfinder optical system capable of obtaining given magnification and a given eyepoint, suitable for an SLR digital camera and an SLR camera, an optical apparatus equipped therewith, and a method for expanding observation. The viewfinder optical system M including an eyepiece optical system 15 for observing a real image of an object formed by an objective lens 11 through an erecting image forming member 14, the eyepiece optical system 15 consisting of, in order from the object along an optical axis, a double concave negative lens, a double convex positive lens, a lens, and a meniscus lens having a convex surface facing the object; an optical apparatus 10 equipped therewith; and a method for expanding observation.

Abstract: A illumination system for variable direction of view instruments is disclosed generally comprising an endoscope having a longitudinal axis and a variable view vector that pivots about a pivot axis angularly offset from the longitudinal axis. The view vector has an attendant viewing field that travels along a path as the view vector pivots, defining a viewing range. A source of illumination is arranged in a plane offset from the plane in which the view vector pivots and provides an annular, solid angle of illumination that covers the viewing range. In certain embodiments, the pivot axis is perpendicular to the longitudinal axis and the illumination plane is parallel to the pivot plane. In some embodiments, the source of illumination is a plurality of light emitting diodes arranged around the pivot axis.

Abstract: A telescope optical system TL comprising, in order from an object side: an objective lens 1; an erecting prism 2; and an eyepiece 3; the objective lens 1 comprising, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power, focusing being carried out by moving the second lens group G2 along an optical axis, and an image position being movable by moving the third lens group G3 in a direction perpendicular to the optical axis, thereby providing a telescope optical system having optimum optical performance for a telescope.

Abstract: A stereomicroscope of the Greenough type includes a first monocular microscope and a second monocular microscope, which define a first beam path and a second beam path, respectively, wherein the first and second microscopes are arranged at a convergence angle to one another and comprise magnification systems for producing equal magnifications which can be varied synchronously with one another. At least one optical element in the first microscope has a different optically effective diameter compared to at least one corresponding optical element in the second microscope.

Abstract: There is disclosed a camera having a first imaging medium which acquires subject image data from a subject light flux transmitted through a photographing lens; an optical path branching member which is disposed in an image pickup optical path of the first imaging medium to branch an optical path of the subject light flux; a primary image forming surface on which the subject light flux branched by the optical path branching member forms an image; and a second imaging medium which picks up the subject image formed on the primary image forming surface. When the present camera satisfies at least one of a plurality of optical conditions, the amount of shading of the light flux guided to the second imaging medium is reduced.

Abstract: A compact spotting scope includes a housing with an outer surface having a grasping region sized and shaped to fit in a user's hand. An optical element positioned within the housing is adjusted by manually rotating a side-mounted adjustment knob that extends laterally from the outer surface of the housing opposite the grasping region. The side-mounted position of the adjustment knob allows the arm and wrist of the focusing hand to be maintained in an ergonomic position during manipulation of the adjustment knob, thereby further facilitating steady support. An internal support member of the spotting scope includes a frame portion and a generally tubular portion, which are preferably formed together of unitary one-piece construction for aligning optical elements of the spotting scope.

Abstract: A device for the magnified viewing of an object, from which object rays originate, includes a lens system (1) for collecting object rays. In one embodiment of the invention, the device includes: a display (2) from which display rays (14) originate, and; a left eyepiece (3) and a right eyepiece (3), via which a left-eye and right-eye beam (5 and 6) of visual field rays are projected into the left and right eye of a user of the device. According to this inventive embodiment, an optical component (7, 8, 9, 10, 11) is provided with a physical ray distributing surface (12) on which a beam of collected object rays (13) and a beam of display rays (14) can be superimposed and can be divided up into the left-eye beam and right-eye beam (5, 6) of the visual field rays. This enables a reduction in losses of display rays and object rays.

Abstract: A stereomicroscope includes a first beam path and a second beam path, wherein in the first beam path a first telescope system is provided and in the second beam path a second telescope system is provided. An observation unit comprising a first and a second observation unit is also provided. At least one optical element of the first telescope system compared to at least one corresponding optical element of the second telescope system has a different optically effective diameter. Between the first telescope system and the second telescope system and the first and the second observation units a prism group is provided which can be moved in the beam path of the first telescope system with the larger diameter of the entrance pupil.

Abstract: The invention concerns a tube (3) for a microscope (1), in which at least two beam paths are provided, wherein a change-over device is provided in the tube (3), by means of which device a first (5) or a second flat-field optical element can be rotated and/or moved selectively into the beam paths (2) of the beam paths (8) aligned by an objective (7), for aligning the beam paths for an observer, wherein the second flat-field optical element has a function of exchanging the beam paths and inverting the image. Further, the invention concerns a microscope (1) with such a tube (3).

Abstract: In a binocular telescope with an adjustable prism module, an eyepiece lens module, a prism module and an objective lens module are installed inside a telescope tube of the binocular telescope. The prism module includes a prism base, a first right-angle prism, a Porro prism, a second right-angle prism and a support base, and an exit surface of the first right-angle prism is connected with an incident surface of the Porro prism, and the second right-angle prism is set on the support base, and the incident surface of the second right-angle prism is attached to the Porro prism. The first and second right-angle prisms can be adjusted to change the angle of optical axes among the prism module, the eyepiece lens module and the objective lens module to prevent a distortion of the optical imaging.

Abstract: A system for measuring the size of free air balls for use with a wire bonder having a wire bonding tool and an Electric Flame Off (EFO) device is provided. The system includes an imager disposed above a first image plane, a prism disposed below the imager, and at least one lens positioned between the first image plane and the prism in a first optical path. The at least one lens is positioned between the prism and the imager in a second optical path, where the second optical path is different from the first optical path. An image of the free air ball disposed at a lower portion of the wire bonding tool is provided to the imager via the prism and the at least one lens.

Abstract: A direct vision periscope is disclosed having a second set of mirrors strategically positioned within a wide angle trapezoidal periscope. The main optical path has a vertical field of view of 24° above and below horizontal while the secondary optical path provides a field of view of 12 to 59° above horizontal to allow the occupants to see elevated areas. When used on military vehicles, multiple periscopes may be disposed about the operator's compartment to create a near panoramic view.

Abstract: Optical devices and methods for providing wide field magnification to assist the visually impaired, and others, are provided. The optical device includes a plurality of telescopic lens sets, for example, a plurality of telescopes, each telescopic lens set including an objective lens and an ocular lens, and a plurality of refracting optical elements, for example, prisms, positioned in front of at least some of the objective lenses. The refracting optical elements are adapted to at least partially redirect light rays toward at least some of the objective lenses to provide wider fields of view, for example, a wider contiguous field of view. Aspects of the invention can provide fields of view up to 40 degrees or more. These wider fields of view can greatly enhance the visual acuity of the visually impaired, as well as provide wider fields of view for non-corrective purposes, such as for field observations.

Abstract: A combined prismatic condenser board includes a base having a surface on which a prismatic structure is formed. The prismatic structure includes a plurality of parallel rib-like prisms extending in a longitudinal direction and a plurality of parallel rib-like prisms extending in a lateral direction, which intersect each other. The rib-like prisms have a substantially triangular cross-sectional shape and have ridges that are selectively of different heights. With the rib-like prisms extending in different directions and having ridges of different heights, the combined prismatic condenser board realizes light condensation in the different directions and provides optimum view angles in the different directions.

Abstract: The invention relates to a telescope which is used to inject and/or to extract, by reflection, emitting and/or capturing bundles of beams. According to the invention, at least one deflecting means is joined to the planar surface by means of at least one lens of the telescope objective unit, which is embodied as a plan convex or plan concave lens. The lens is used as a lens of the objective unit and as a holder for the deflection means. The number of optical components in the telescope about one of the holders is reduced due to the dual function thereof.

Abstract: An observation optical system has a negative lens unit placed at the most object-side position; an annular prism placed on the image side of the negative lens, having a reflecting surface on the negative lens side; and an imaging lens unit arranged on the image side of the negative lens and the annular prism.

Abstract: The auto level with a laser radiates laser light along an optical axis of a visible optical system and comprises of a visible optical system with an automatic horizontal compensation mechanism prism mirror and a beam splitter disposed between an objective lens and an eyepiece. The auto level with a laser is capable of measuring from 5 meters to 300 meters when using the laser light and 0.8 meters to infinity when using the optical sight.

Abstract: A substantially neutral filter across the white-light spectrum is obtained by minimizing the wavelength-dependent effects of filtering components and of reflective coatings on surfaces. The incoming light is captured by a first prism and directed toward the interface formed by the optical contact of a second prism with a face of the first prism, where the light is partially reflected internally and partially transmitted into the second prism. The reflected light is further reflected internally and directed toward the image surface out of the first prism. The fraction of light transmitted into the second prism is reflected back and redirected out of the system toward the incoming beam. The amount of energy directed toward the image plane is controlled by the judicious selection of the refractive indices in the two materials at the contacting interface of the first and second prisms.

Abstract: A compact spotting scope includes a housing with an outer surface having a grasping region sized and shaped to fit in the palm of a user's hand so that the spotting scope can be held at eye level with one hand in an ergonomic arm and wrist position for steady support. An optical element positioned within the housing is adjusted by manually rotating a side-mounted adjustment knob that extends laterally from the outer surface of the housing opposite the grasping region. The side-mounted position of the adjustment knob allows the arm and wrist of the focusing hand to be maintained in an ergonomic position during manipulation of the adjustment knob, thereby further facilitating steady support. An internal support member of the spotting scope includes a frame portion and a generally tubular portion, which are preferably formed together of unitary one-piece construction for aligning optical elements of the spotting scope.

Abstract: A digital telescopic sight includes an objective lens group (202), a light collecting lens (204), an erecting lens group (206), an eyepiece lens group (212), a semi-reflecting mirror (208) and an image sensor (210). The incident exterior light rays are sequentially transmitted through the objective lens group, the light collecting lens and the erecting lens group, and then incident onto the semi-reflecting mirror. The semi-reflecting mirror reflects a portion of the light rays onto the image sensor, and transmits the remaining primary light rays to the eyepiece lens group for enabling the user to view the image. The image sensor receives the reflected portion of the light rays, converts it into an electrical signal, and finally transmits the electrical signal to a digital signal processor for further image signal processing.

Abstract: A fused thermal and a direct view aiming sight includes an optical gun sight, a thermal sight, and a beam combiner. The optical sight generates a direct view image of an aiming point or reticle superimposed on a target scene. The thermal sight generates a monochromic thermal image of the target scene. The combiner is positioned behind a 1× non-magnified optical sight and the thermal sight and in front of an exit pupil of the thermal sight. The combiner is positioned right behind the intermediate image plane of a magnified optical sight between an objective lens and an eyepiece. The combiner passes the direct view image and reflects the thermal image to the exit pupil to fuse the thermal image onto the direct view image for an operator to see at the exit pupil as a combined thermal and direct view optical image of the target scene together with the aiming reticle.

Abstract: An electrooptic device includes an electrooptic layer and a condensing substrate. The condensing substrate lets the light incident on the condensing substrate into the electrooptic layer. The condensing substrate includes a base and prisms. The prisms are disposed along the boundary region of a plurality of pixel regions. The prisms have a refraction index different from that of the base. At least a portion of the prisms is located within the base.

Abstract: A display device (4) for a telescope system is disposed between a first image plane (10) and a second image plane (20) of the telescope system. The display device includes a signal emitter (41), a converging lens group (42) positioned adjacent to the signal emitter, and a dioptric imaging lens group (43) positioned adjacent to the converging lens group. The optical signal emitted by the signal emitter is first transmitted through the converging lens group, then incident onto the dioptric imaging lens group, and finally imaged onto the second image after reflection of the dioptric imaging lens group. Therefore, both the image size and brightness of the displayed signal viewed by the observer can maintain unchanged in spite of the magnification variation of the telescope system.

Abstract: Apparatus for imaging an area of a surface along a viewing angle that is oblique to the surface includes an afocal optical relay, which is adapted to form a tilted initial image of the area by collecting optical radiation from the area along an optical axis oriented at the viewing angle. A tilt correction unit is coupled to correct a tilt of the initial image so as to form a substantially undistorted intermediate image. A magnification module is coupled to focus the intermediate image onto an image detector.

Abstract: A trinocular tube for stereo microscopes with an inclined binocular eyepiece whose angle can be adjusted and with two stereo microscope beam paths. The trinocular tube includes, in the beam paths, a first tube unit which can be connected to the body of the stereo microscope. A connection piece for cameras is arranged at the first tube unit. A second tube unit is arranged at the first tube unit so as to be swivelable around an axis and which is connected to an eyepiece tube unit that is swivelable around the optical axis of the respective beam path. The trinocular tube also includes a roof mirror, a deflecting element and an optical axis that is swivelable around a second swiveling axis.

Abstract: A tilting system for an observation device, in particular for a microscope, with at least one objective device and at least one optical device for passing at least one beam path from an entrance region to an exit region of the tilting system is described, wherein the optical device has at least one optical element in the form of a prism for tilting and for image reversion of the beam path as well as for guiding it further into at least one ocular device. According to the invention, a particularly cost-favorable and structurally simple configuration of the tilting system with a mechanical structural length that is simultaneously as small as possible is provided by configuring the optical elements for tilting the beam path as well as at least one prism for image reversion in a special way and by arranging them in a specific manner relative to one another in the beam path. In addition, an observation device with a corresponding tilting system is described.

Abstract: Two reflective surfaces disposed in a predetermined angular orientation inside the optical tube assembly of a telescope intercept the optical beam and deliver it from the objective to the eye-piece. By translating these surfaces simultaneously along the axis bisecting the angle between them, the separation between the focal points of the objective and the eye-piece is adjusted as required to re-focus the telescope in a continuous and reversible fashion without changing its overall dimensions.

Abstract: A substantially neutral filter across the white-light spectrum is obtained by minimizing the wavelength-dependent effects of filtering components and of reflective coatings on surfaces. The incoming light is captured by a first prism and directed toward the interface formed by the optical contact of a second prism with a face of the first prism, where the light is partially reflected internally and partially transmitted into the second prism. The reflected light is further reflected internally and directed toward the image surface out of the first prism. The fraction of light transmitted into the second prism is reflected back and redirected out of the system toward the incoming beam. The amount of energy directed toward the image plane is controlled by the judicious selection of the refractive indices in the two materials at the contacting interface of the first and second prisms.