Abstract: A deflection prism assembly for an endoscope having a lateral viewing direction. The deflection prism assembly including: a prism holder; a deflection prism which is received in the prism holder; and at least one electrical heating element for heating the deflection prism. The prism holder includes a reception component and an adjustment component. The deflection prism is attached to the reception component and the adjustment component provides a stop for the deflection prism in an axial direction. Wherein the at least one electrical heating element being disposed in or on the reception component; and the at least one electrical heating element at least partially extending in one or more of a circumferential direction or longitudinal direction of the reception component.

Abstract: A lamp includes a light source and a light pipe including a light transmissive medium with an elongated body extending along an axial axis. The light pipe has an input for receiving light from the light source and a plurality of prism optics extending into an outside surface of the elongated body in a direction of the axial axis, wherein the plurality of prism optics each has an angle in the range of about 115° (degrees) to 145° (degrees).

Abstract: A heat dissipation device for a projector includes a light source, a light valve, a prism set, a shading element, and a projection lens. The light source emits a light beam. The light valve is disposed downstream of a light path of the light source to receive the light beam, convert a part of the light beam into image light and another part of the light beam into an ineffective light beam. The prism set includes at least one prism, receiving the image light and the ineffective light beam. The shading element includes a heat dissipation part and is disposed downstream of a light path of the prism set and used to block the ineffective light beam from the prism set. The projection lens is disposed downstream of the light path of the prism set.

Abstract: A light path adjustment mechanism includes a bracket, a light valve, a carrier, a first axis, a second axis and an optical plate member. A surface normal of a surface of the light valve crosses the bracket to define an intersection closest to the surface of the light valve, and the bracket has an end point furthest from the intersection measured in the direction of the surface normal. A distance between the intersection and the surface measured in the direction of the surface normal is smaller than a distance between the intersection and the end point measured in the direction of the surface normal.

Abstract: A prism holder for use with a surgical instrument, having a prism. The prism holder including: a casing for receiving the prism; and at least one prism pressure element configured to be brought into contact with a pressure surface of the prism; wherein the casing having an opening for arrangement of the at least one prism pressure element in the opening.

Abstract: The disclosed head-mounted display assemblies may include a first eyecup and a second eyecup that are configured for respectively positioning a first lens and a second lens in front of intended locations of a user's eyes when the head-mounted display assembly is donned. The first eyecup and the second eyecup may be movable relative to each other to adjust for an interpupillary distance of the user's eyes. A single near-eye display screen may be configured for displaying an image to the user through the first and second eyecups. An enclosure over the single near-eye display screen may include a first transparent component positioned between the first lens and the single near-eye display screen and a second transparent component positioned between the second lens and the single near-eye display screen. Various other methods, devices, systems, and assemblies are also disclosed.

Abstract: An objective lens assembly includes a first lens group configured to have a positive refractive power, the first lens group being positioned to receive visible light along an optical path extending therethrough. The objective lens assembly further includes a second lens group configured to have a negative refractive power, the second lens group being positioned along the optical path to receive the visible light from the first lens group. The objective lens assembly further includes a center lens disposed between the first lens group and the second lens group and an aperture stop centered along the optical path and positioned in front of the first lens group to direct visible light from a scene to the first lens group.

Abstract: The present specification relates to a film for compensating for a viewing angle, which comprises a base substrate; a pattern layer; and an optical layer, and in which the pattern layer has a first surface comprising a flat surface and a second surface facing the first surface, and the second surface comprises a plurality of protrusions comprising a curved surface, thereby improving a contrast ratio and a viewing angle and decreasing a color band phenomenon, and a polarizing plate comprising the same, and a display device comprising the same.

Abstract: A projector including a light source, a first prism, a second prism and a digital micro-mirror device (DMD) is provided. The light source emits light. The first prism includes a first surface, a second surface and a third surface which are connected to each other around the perimeter thereof, and the illumination light enters the first prism through the first surface. The second prism has a fourth surface and a fifth surface which are connected to each other, and the fourth surface faces the second surface of the first prism. The DMD faces the third surface. The illumination light sequentially passes through the first surface, is reflected by the second surface, passes through the third surface, and reaches the DMD. The DMD converts the illumination light into image light, and the image light sequentially passes through the third surface, the second surface, the fourth surface and the fifth surface.

Abstract: A head-up display of the present disclosure projects a display image on a transparent reflecting member. The head-up display includes: a display device that displays the display image; and a projection optical system that projects the display image displayed on the display device. On an assumption that light reaching a center of a viewpoint region of the observer and corresponding to a center of the virtual image is reference light, the projection optical system includes a prism element that has an incident surface, a reflection surface, and an emitting surface different from the incident surface sequentially in an optical path from the display device. The emitting surface is inclined to the reference light. An inclination amount ?2 of the reference light emitted from the emitting surface with respect to the emitting surface lies in a range of 15°<|?2|<45° in the optical path from the display device.

Abstract: An optical member driving mechanism is provided, including a movable portion, a fixed portion, and a driving assembly. The movable portion is connected to an optical member. The fixed portion has an accommodating space, and the optical member is received in the accommodating space. The movable portion is movable relative to the fixed portion. The driving assembly is configured to drive the movable portion to move relative to the fixed portion.

Abstract: An optical element has a first member having a first refractive index and a second member having a second refractive index different from the first refractive index. The optical element has a first transmissive surface, a reflective surface, and a second transmissive surface arranged from a demagnifying side toward a magnifying side in order. The first transmissive surface and the reflective surface are located in one side with respect to an optical axis of the optical element. The second transmissive surface is located in the other side with respect to the optical axis of the optical element. the reflective surface has a concave shape.

Abstract: Provided is a surveying instrument including a measuring unit including a tilt sensor configured to acquire tilt angle data of the instrument, and an environment sensor to acquire environment data correlating with a leveling time and leveling accuracy, a leveling unit including a leveling drive unit and configured to level the instrument, an arithmetic control unit configured to control the measuring unit and the leveling unit, and a storage unit configured to store the environment data, leveling result data of the leveling unit, and information on leveling operation conditions. The storage unit has surveying instrument-specific information.

Abstract: Provided are an optical illumination system, and a projection device. In an example, the optical illumination system includes a DMD, a lens assembly and a RTIR assembly. The lens assembly adjusts a light beam. The RIM assembly includes a first plano-convex lens and a wedge prism. The first plano-convex lens includes a plane surface and a convex surface and is configured to refract the light beam adjusted by the lens assembly. The wedge prim includes a first side surface, a second side surface and a third side surface. The plane surface of the first plano-convex lens is glued with the first side surface of the wedge prism. The wedge prism is configured to receive and refract the light beam refracted by the first plano-convex lens through the first side surface, and the light beam refracted by the first side surface is transmitted through the second side surface.

Abstract: The present invention provides a structure of short-throw ambient light rejecting screen, which comprises a base and an optical structure device disposed on the base. The optical structure device includes a plurality of optical structure parts. Each of the plurality of optical structure parts includes a first side, a second side, and a base part. The first side and the base form a first angle for reflecting a light source. The second side and the base form a second angle for absorbing a light source. The base part is a length on the base confined by first side and the second side. The first angle is 20˜40 degrees. The second angle is 70˜90 degrees. The length on the base part is 250˜350 um. By adjusting the first angle, the second angle, and the length on the base part of each optical structure part, the height of the optical structure part can be maintained constant. In addition, the differences between the incident projection angles can be reduced as well.

Abstract: Solid state light engines are disclosed that emit a bright, non-symmetrical emission pattern, with a relatively high luminous flux and from a relatively small area. The light engines can be used in many different types and sizes of light sources, with some embodiments providing a light quantity, quality and distribution similar to conventional J-type Halogen light sources. The light engines are arranged with integral power supplies and heat management features that allow for the engines to provide high emission intensities while generating significantly less heat at the light source. This can result in significantly higher efficiency and greater life space. In some embodiments, the light can perform similarly to a halogen J-type Lamp 80 mm light tube, while generating similar or greater amounts of light. The light engines according to the present invention provide the capability to be used in low profile light fixtures.

Abstract: One embodiment of the present disclosure provides a black microprismatic retroreflective film. The black microprismatic retroreflective film comprises a body layer and a black color layer. The body layer includes microprismatic optical elements. The black color layer gives the black microprismatic retroreflective film a daytime color of black. The black microprismatic retroreflective film has a coefficient of retroreflectivity greater than 50 cd/lx/m2 at a ?4 degree entrance angle and 0.2 degree observation angle.

Abstract: A linear light fixture with gap filler elements. The fixture comprises two primary structural components: a base and a light engine, which may be removably attached. The base comprises a body with end panels at both ends and is mountable to an external structure. The light engine comprises the light sources, an elongated lens, and any other optical elements that tailor the outgoing light to a particular profile. A gap filler element is disposed between the light engine and the end panels at one or both ends of the base to fill the space between those elements, giving the appearance that the light engine extends continuously to the end panel and eliminating direct imaging of the light sources outside the fixture. External reflectors may also be included to further shape the output beam.

Abstract: A modular troffer-style fixture that is well-suited for use with solid state light sources, such as LEDs, to provide a surface ambient light (SAL). The fixture comprises two structural components: a housing subassembly and a lighting subassembly. These two subassemblies may be removably attached to operate as a singular fixture. Many different lighting subassemblies may be compatible with a single housing subassembly and vice versa. The housing subassembly comprises a body that is mountable to an external structure. The lighting subassembly comprises the light sources and optical elements that tailor the light to achieve a particular profile. Electronics necessary to power and control the light sources may be disposed in the housing subassembly, the lighting subassembly, or both. Various mount mechanisms may be used to attach the fixture to a surface such as a ceiling or a wall. Multiple fixtures can be connected serially to provide an extended continuous fixture.

Abstract: The invention relates to a plasmonic optical security component comprising two layers (2, 4) made of transparent dielectric material and a metal layer (3) arranged between said transparent dielectric material layers in order to form two dielectric-metal interfaces (31, 32).

Abstract: The invention relates to a zoom objective lens with continuously adjustable magnification, comprising five lens groups, where the first lens group, the second lens group and the fifth lens group are fixed in relation to an object. The third lens group and the fourth lens group are axially displaceable. The following conditions apply to the lens: the variable air gap between the second lens group and the third lens group decreases or has a turning point with a transition from a low to a high magnification ?, the refractive power of the second, third and fifth lens groups is positive and the refractive power of the fourth lens group is negative.

Abstract: A sensor is provided for monitoring a mineral acid dissolved in a liquid. The sensor includes an internal reflection window which, in use, is in direct contact with the liquid. The sensor further includes a mid-infrared light source which directs a beam of mid-infrared radiation into said window for attenuated internal reflection at an interface between the window and the liquid. The sensor further includes a first narrow bandpass filter which preferentially transmits mid-infrared radiation over a band of wavelengths corresponding to an absorbance peak of the dissolved mineral acid to filter internally reflected mid-infrared radiation received from the window. The sensor further includes an infrared detector which detects filtered mid-infrared radiation transmitted through the first filter.

Abstract: A beamsplitter includes an optical substrate with a first surface configured to receive a beam of multi-spectral light, to reflect a first band of the multi-spectral light and to transmit a second band of the multi-spectral light through the optical substrate to be emitted from a second surface of the optical substrate opposite the first surface. The second surface is a freeform surface. A system includes a telescope configured to focus multi-spectral light into a beam. The system also includes a beamsplitter as described above optically coupled to the telescope so the first surface of the beamsplitter is configured to receive the beam of multi-spectral light from the telescope.

Abstract: Illumination systems are described for illuminating a target area, e.g., a floor of a room, using active illumination devices in optical communication with passive illumination devices. The active and passive illumination devices of the illumination system are configured and arranged relative to each other in a variety of ways so a variety of intensity distributions can be provided by the illumination system. Such illumination system is implemented to provide light for particular lighting applications, including office lighting, garage lighting, or cabinet lighting.

Abstract: A linear light fixture with gap filler elements. The fixture comprises two primary structural components: a base and a light engine, which may be removably attached. The base comprises a body with end panels at both ends and is mountable to an external structure. The light engine comprises the light sources, an elongated lens, and any other optical elements that tailor the outgoing light to a particular profile. External reflectors are included to further shape the output beam. The reflectors may be shaped to define louvers which direct some of the emitted light in a direction opposite the primary emission direction, e.g., as uplight. The fixtures may be connected in a serial arrangement using a joiner.

Abstract: Methods, systems, and apparatus for optical wavelength selective switching. One 2×2 wavelength selective switch array includes a plurality of optical input ports configured to receive one or more optical input beams, and a plurality of optical output ports configured to receive one or more one or more optical output beams wherein the plurality of optical input ports and optical output ports form an array of 2×2 optical port pairs; one or more optical conditioning and wavelength dispersion elements; a polarization modulator array having a plurality of polarizing modulation cells, each cell configured to independently change a polarization orientation of an optical beam passing through the cell and associated with a particular wavelength channel; and a polarization-selective beam-routing optical element configured to route each particular input beam to either a first output port or a second output port according to polarization orientation.

Abstract: An optical unit includes a digital micromirror device in which each of micro-mirrors is driven biaxially in ON/OFF control, a first prism directs illumination light to the digital micromirror device, a second prism including an OFF-light reflecting surface reflects OFF light reflected from the micro-mirrors in an OFF state and transmits ON light reflected from the micro-mirrors in an ON state, and a third prism emits the ON light incident from the second prism toward a projection side. The micro-mirrors reflect the OFF light so that an optical axis of the OFF light is directed away from a projection-optical-axis plane including an optical axis of the ON light and an optical axis of the illumination light.

Abstract: A modular fixture that is well-suited for use with solid state light sources, such as LEDs, to provide a surface ambient light (SAL). The fixture comprises two structural components: a housing subassembly and a lighting subassembly. These two subassemblies may be removably attached to operate as a singular fixture. Many different lighting subassemblies may be compatible with a single housing subassembly and vice versa. The housing subassembly comprises a frame that is mountable to an external structure. The lighting subassembly comprises the light sources and optical elements that tailor the light to achieve a particular profile. Electronics necessary to power and control the light sources may be disposed in the lighting subassembly. Various mount mechanisms may be used to attach the fixture to a surface such as a ceiling or a wall. Multiple fixtures can be connected serially to provide an extended linear fixture.

Abstract: A projector includes a light source, a digital micro-mirror device (DMD), a first prism, a second prism, and a lens. The light source is used for emitting an incident light. The DMD is used for receiving and reflecting the incident light as an image light. The first prism is disposed between the light source and the DMD. The second prism is disposed between the first prism and the DMD. The first prism includes a first plane, a second plane, and an intermediate portion. The intermediate portion adjoins the first plane and includes a reflecting portion. The incident light from the second plane is reflected by the reflecting portion and then passes through the second plane. The second prism includes a fourth plane, a fifth plane, and a sixth plane. When the DMD is operated in an on-state, the image light passes through the sixth plane.

Abstract: In various embodiments, a light emitting device is provided comprising a plurality of first solid state light sources for emitting first light with a first spectral distribution, and a first light guide comprising a first light input surface, a first end surface extending in an angle with respect to each other and at least one first further surface extending parallel to the first light input surface. The first light guide receiving the first light at the first light input surface, and guiding a part of the first light to the first end surface. The light emitting device further comprises one first optical element, for shaping light that is coupled out of the first light guide through a part of the at least one first further surface such as to provide a first shaped light, and at least one second optical element on the first end surface.

Abstract: A prism group including a first, a second, and a third prisms is provided. The first prism has a first light incidence surface, a first light emitting surface, and a first connecting surface. The second prism has a second light incidence surface, a second light emitting surface, and a second connecting surface. The second light incidence surface is located between the first light emitting surface and the second light emitting surface. A first air gap is between the second light incidence surface and the first light emitting surface. The third prism has a third light incidence surface, a third light emitting surface, and a third connecting surface. The third light incidence surface is located between the second light emitting surface and the third light emitting surface. A second air gap is between the third light incidence surface and the second light emitting surface. A projection apparatus is also provided.

Abstract: An illumination optical system is provided with: a lens that condenses first luminous flux emitted from an optical fiber at an angle of divergence of ?1; a lens that condenses second luminous flux that has a color that is different from the color of the first luminous flux and that is emitted from an optical fiber at an angle of divergence of ?2 (??1); and a dichroic mirror that is provided at the position at which the optical axis of the lens intersects at a right angle with the optical axis of the lens, that transmits the first luminous flux that is irradiated from the lens, and that reflects the second luminous flux that was irradiated from the lens in the direction in which the first luminous flux was transmitted.

Abstract: In a method of manufacturing an electrode of a thermionic converter, a carbide layer is formed on a base material by a vapor synthesis, an N-type diamond layer doped with a donor impurity is formed on the carbide layer by a vapor synthesis, and a surface of the N-type diamond layer is terminated with hydrogen. The base material is made of a metal, and the carbide layer is made of a metal carbide.

Abstract: This disclosure relates to light engines for use in lighting fixtures, such as troffer-style lighting fixtures. Light engines according to the present disclosure have integrated features that eliminate the need for additional components such as a Printed Circuit Board (PCB), a heat sink, a cover portion, a lens and/or a reflective element. Devices according to this disclosure can comprise a rigid body, conductive elements arranged into electrical pathways and light sources such as light emitting diodes (LEDs). Devices according to this disclosure can further comprise integrated cover, lens and/or reflective element features. Methods for the manufacture of such devices are also disclosed.

Abstract: This disclosure relates to lighting fixtures, such as suspended lighting fixtures. Devices according to the present disclosure provide lighting fixtures capable of emitting in one or more primary directions, while simultaneously emitting in a direction toward a mount surface, reducing undesirable areas of insufficient light and more efficiently illuminating a space. Lighting fixtures disclosed herein can achieve this increase in illumination efficiency in many ways, including utilizing various lighting element arrangements, such as dual-sided lighting elements, and various lens arrangements, such as lens shape affecting the direction of emitted light.

Abstract: This disclosure relates to suspended linear lighting fixtures that are arranged to accept lighting elements. Lighting fixtures according to the present disclosure comprise at least one body and at least one suspension mechanism. These lighting fixtures can be arranged such that electrical and mechanical connections can be provided at various locations along their length, rather than only at the distal ends of the fixtures. The fixtures can also comprise various connectivity features that allow further arrangements, designs and spatial adjustments. Lighting systems utilizing these fixtures are also disclosed.

Abstract: A touch projection system includes a screen, an image-capturing device, a micromirror device, and a TIR prism disposed in front of the micromirror device. The TIR prism includes an optical path compensation structure or a hollowed channel, so that an image light from the screen, traveling through the TIR prism to be reflected by the micromirror device, can travel through the optical path compensation structure or the hollowed channel to avoid a probable optical path difference on the image light due to traveling through the TIR prism. Thereby, the invention can solve that a distortion may be induced in a touch image formed by the image-capturing device receiving the image light reflected by the micromirror device.

Abstract: A mirror device permitting a driver using the device to view forward and rearward of the vehicle. The device provides the visual field of the conventional and/or modern side-view mirror and also extends the visual field to view areas, regions, and/or objects which are forward to allow a line of sight that might otherwise be blocked by an obstruction.

Abstract: This disclosure relates to light engines for use in lighting fixtures, such as troffer-style lighting fixtures. Light engines according to the present disclosure have integrated features that eliminate the need for additional components such as a Printed Circuit Board (PCB), a heat sink, a cover portion, a lens and/or a reflective element. Devices according to this disclosure can comprise a rigid body, conductive elements arranged into electrical pathways and light sources such as light emitting diodes (LEDs). Devices according to this disclosure can further comprise integrated cover, lens and/or reflective element features. Methods for the manufacture of such devices are also disclosed.

Abstract: A first prism member includes a plurality of light condensing structures that are formed at the front surface and condense the light having entered thereat and a plurality of deflecting structures which deflect light having been condensed via the light condensing structures and output the deflected light; a second prism member includes an entrance surface set so as to face opposite the rear surface of the first prism member; and the light having been deflected and output by the deflecting structures of the first prism member enters the second prism member through the entrance surface of the second prism member, is guided toward the exit surface as the light is reflected at the reflecting structure and at the entrance surface inside the second prism member, and exits through the exit surface.

Abstract: A frame for optics used in interferometers that may include different materials having substantially similar, identical, or as close as practicable coefficients of thermal expansion from the material(s) used to make the beamsplitter and/or compensator without warping, bending, tilting or distorting the optics. The beamsplitter and/or compensator are mounted onto the frame of the interferometer using a three-point method of mounting, preferably using three pins for each component. Preferably, the pins are made of the same material as the beamsplitter and compensator, and all three components are made of Potassium Bromide (“KBr”) or Calcium Fluoride (“CaF2”) such that the optic instrument can operate to scan into the mid or far infrared. Stability in optical alignment is therefore achieved without requiring the optic instrument include only one material. The invention provides stability in situations where it is not possible to utilize a single material for every component of the interferometer.

Abstract: A device forms laser radiation which has partial beams interspaced in a first direction that is perpendicular to the direction of propagation of the laser radiation, especially for forming laser radiation which is emitted by a laser diode bar. The device contains a plurality of reflective surfaces on which at least one of the interspaced partial beams can be reflected in such a manner that the distances of the partial beams are smaller relative to each other after reflection than before reflection.

Abstract: An aspect of the disclosed subject matter includes a method of reducing the laser absorption of a beam reverser prism consisting of at least one of the following: increasing a first distance between a first incident point and a chamfered corner, wherein the first incident point is on a first reflective surface of the prism and the chamfered corner is formed between the first reflective surface and a second reflective surface of the prism, wherein the chamfered corner has a chamfered surface; increasing a second distance between a second incident point and the chamfered corner, wherein the second incident point is on the second reflective surface of the prism; and increasing a reflectivity of the chamfered surface of the chamfered corner of the prism. A method of determining a prime cut for an optical component is also disclosed. A laser including at least one prime cut optical component is also disclosed.

Abstract: An interior rearview mirror assembly includes a mirror casing and a prismatic reflective element. The mirror casing is a unitarily molded mirror casing having at least one attachment surface. The prismatic reflective element includes a glass substrate having a front surface and a rear surface and a perimeter edge about a periphery of the glass substrate. A mirror reflector is established at the rear surface of the glass substrate. The perimeter edge of said glass substrate has a generally rounded surface disposed between the front surface and the mirror casing. The prismatic reflective element is attached at the attachment surface of the mirror casing. The perimeter edge of the glass substrate is exposed to and is viewable by the driver of the vehicle when the interior rearview mirror assembly is normally mounted in the vehicle.

Abstract: A prism used in analysis utilizing surface plasmons is prism of a dielectric medium with a predetermined reflective index. Trapezoidal prism comprises an incident surface on which excitation light is incident from outside, a reflective surface at which the excitation light incident on the incident surface is reflected, an emission surface from which the excitation light reflected by the reflective surface is emitted; and an opposite surface which opposes the reflective surface. The opposite surface is a recessed sink-mark surface.

Abstract: An illumination system includes an LED module and an illuminated area. The LED module includes an LED, and a lens mounted in light path of the LED. The lens includes a light source recess, a first light emitting surface, a critical reflecting surface, and a second light emitting surface intersecting with the first light emitting surface and being on same side with the first light emitting surface. The first light emitting surface can receive more light quantity than the second light emitting surface. Although the light emitted from the first light emitting surface may have greater attenuation than the light emitted from the second light emitting surface, light emitted from the first light emitting surface can make up the intensity losses of attenuation as the first light emitting surface receives more light quantity than the second light emitting surface. As a result, the illumination system has a uniform illumination pattern.

Abstract: In an optical unit of a projective display device which projects light source light reflected by a DMD, one prism of TIR prisms has a first boundary surface which is arranged in parallel to an emission surface of the light source light of other prism at a predetermined distance and on which the light source light from other prism is incident and a second boundary surface which is provided to face the DMD and emits the light source light illuminating the DMD and on which reflected light from the DMD is incident. When a swinging angle of minute mirrors of the DMD is set as ±?, a refractive index of the prisms is set as n, an angle formed by the first boundary surface and the second boundary surface is set as ?, and an emission angle of the light source light with respect to the DMD in the second boundary surface is set as ?, the swinging angle ?, the refractive index n, the angle ?, and the angle ? satisfy a predetermined relation.

Abstract: Embodiments disclose a two imager biometric sensor. In some embodiments, the two imagers can include a direct imager and a TIR imager. In some embodiments, multispectral light sources can be used to illuminate target tissue imaged by two imagers. In some embodiments, composite images can be created from images detected using both imagers.

Abstract: A polarizing beam splitter (“PBS”) includes a glass wedge having a first oblique surface, a multi-layer polarizing coating disposed on the first oblique surface of the glass wedge, and a plastic wedge having a second oblique surface. The first oblique surface of the glass wedge is mated to the second oblique surface of the plastic wedge with the multi-layer polarizing coating sandwiched between the first and second oblique surfaces.

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.