Abstract: An illumination device can include a light source; and a light guiding lens for receiving light from the light source. The light guiding lens includes a light emission portion that extends in a predetermined direction and has a main surface with reflecting cuts, and a light guiding portion provided to the light emission portion at an end portion thereof in the predetermined direction. The light guiding portion is configured to project more than the light emission portion in a thickness direction of the light emission portion and extend along the end portion of the light emission portion. The light source is disposed to face to an end face of the light guiding portion in an extending direction of the light guiding portion, the end face projecting more than the light emission portion. An end face of the light guiding portion has reflecting cuts arranged in the extending direction.

Abstract: A luminaire having a waveguide suspended beneath a mounting element, the waveguide has a first surface proximal to the mounting element, a second surface distal to the mounting element, and an edge between the first and the second surfaces. At least one cavity extends into the waveguide from the first surface to the second surface. A LED component is coupled to the waveguide so as to emit light into the cavity. LED support structures are also disclosed.

Abstract: Discussed is a glass light guide plate that is used in a back light unit of a display device. Some features of the glass light guide plate for the back light unit can be improved by optimizing a relationship between a direction of a bubble inside the glass light guide plate and a light source, the sizes of the bubble and a light guide pattern, and so on, and by optimizing an arrangement density of light guide patterns in each region, a kind of light guide pattern ink (IR-curable ink), a curing condition, a refractive index, and so on to be suitable for the material of the glass light guide plate.

Abstract: A backlight unit includes a first light source, a second light source, and a light guide plate having, on an upper surface, and, on a lower surface, a second pattern. The first pattern extracts, from the light guide plate, light from the first and second light sources, and emits the light towards a display panel. The second pattern extracts, from the light guide plate, light from the second light source, and emits the light toward the display panel. A display panel may include the backlight unit.

Abstract: A backlight module for light-emitting keyboard includes light guide plate having reflective surface, opposing light-emitting surface and plurality of recessed dots located on reflective surface to create optical path of continuous wave-like reflecting portion for facing toward key switch unit in light-emitting keyboard. The spacing between the centers of each two adjacent recessed dots is smaller than or equal to diameter of one single recessed dot. The continuous wave-like reflecting portion exhibits a continuous ring-shaped pattern formed of a series of ring-shaped square waves, triangular waves, sawtooth waves or sine waves and consisting of at least one different cycle waveforms having varying cycle periods, amplitudes or peak-to-peak values that are interleaved in regular or irregular manner.

Abstract: A light guide plate includes a light introduction surface to receive light supplied from a light source module and a light emission surface to emit the light outward, the light emission surface having a larger area than the light introduction surface. The light guide plate is of a material that transmits light and absorbs light in an absorption wavelength band. The light guide plate further includes a plurality of color patterns to convert the light supplied from the light source module into light in the absorption wavelength band.

Abstract: A display device includes a first display panel including a display surface defined by first and second directions, a second display panel spaced apart from the first display panel in a third direction perpendicular to the display surface, and a backlight unit disposed between the first and second display panels to provide a light to the first and second display panels. The backlight unit includes a light emitting element, a first exit light guide plate, a second exit light guide plate spaced apart from the first exit light guide plate, a first light-division light guide member, and a second light-division light guide member.

Abstract: The present disclosure provides a light guide plate-positioning column, a backlight module and a display apparatus. The column comprises a first positioning body for positioning a light guide plate and a second positioning body for positioning an optical film; the second positioning body is located on a side of the first and fixedly connected to it; a projection of the first positioning body in a direction from it toward the second completely covers that of the second, and a projection area of the first positioning body is greater than that of the second; wherein in the direction, a surface on a side of the first positioning body close to the second does not extend beyond a surface on a side of the plate close to the second. Both the requirements of the positioning strength of the plate and the fine positioning of the film can be met.

Abstract: The present disclosure proposes a backlight source of a backlight module. The backlight source includes: one or more strip-shaped source carrier, comprising a plurality of holes arranged on a light emitting surface; the source carrier combined with the plastic frame; the source carrier and the plastic frame enclosing a rectangular frame; a PCB, arranged on the source carrier; and a source, corresponding to the hole and arranged on the source carrier; the source connected to the printed circuit board and transmitting light into the backlight module from the hole. The combination of the plastic frame and the backlight source realizes the respective functions of the conventional plastic frame and the conventional backlight source. Owing to the simplified plastic frame and backlight source, the bezel of the display can be narrower and smaller to satisfy the demands for the display with a narrow bezel.

Abstract: The display device includes a display panel, an optical member, a light guide plate, and a bottom member. The optical member includes a body contacting a bottom surface of the display panel and a plurality of foldable parts extending from the first body. The light guide plate overlaps the body and is disposed below the optical member. The bottom member is disposed below the light guide plate and has a plurality of slits, which correspond to the plurality of foldable parts. The plurality of first foldable parts are bent from the first body, respectively inserted into the plurality of first slits, and fixed to the bottom member.

Abstract: A display apparatus includes a plurality of pixels disposed in an active area, a plurality of non-pixels disposed in a non-active area adjacent to the active area, and a plurality of light guide members disposed on boundary pixels of the pixels in the active area and which extends into the non-active area and is disposed on the non-pixels in the non-active area. The boundary pixels are adjacent to a boundary between the active area and the non-active area, and the light guide members guide light exiting from the boundary pixels to the non-pixels.

Abstract: A photonic device includes a semiconductor wafer having a waveguide formed therein. An end of the waveguide includes a step. The photonic device further includes a semiconductor chip bonded to the semiconductor wafer and having an active region, and a waveguide coupler disposed in a gap between a sidewall of the semiconductor chip and the end of the waveguide. The waveguide coupler includes an optical bridge that has a first end and a second end opposing the first end. The first end of the optical bridge is interfaced with a facet of the active region of the semiconductor chip. The second end of the optical bridge is interfaced with the end of waveguide, and has a portion thereof disposed over the step at the end of the waveguide.

Abstract: A photonic device for converting optical modes of optical beams includes a first port to receive a first beam having a first mode, a mode converter and a second port to transmit the first beam. The mode converter is configured to broaden the first beam to convert the first mode into a second mode and narrow the broadened first beam at an output side of the mode converter, wherein the mode converter includes a guide material having a first refractive index and perturbation segments each having a second refractive index, wherein the first refractive index is greater than the second refractive index, wherein the perturbation segments are arranged in the guide material to cross the first beam.

Abstract: A method for producing a semiconductor device includes the steps of: providing a substrate product including a substrate and a first stacked semiconductor layer disposed on the substrate, the first stacked semiconductor layer including a plurality of semiconductor layers having different compositions that are alternately and periodically stacked with a predetermined period; forming a mask on the substrate product; and etching the first stacked semiconductor layer using the mask. The step of etching the first stacked semiconductor layer includes the steps of: optically monitoring an optical signal including a light component reflected from an etched surface of the substrate product for detecting an endpoint of etching; converting the optical signal to an electric signal to generate a monitoring signal; performing Fourier transform on the monitoring signal to generate a spectrum signal; and determining the endpoint detection of the etching by using the spectrum signal provided by the Fourier transform.

Abstract: A semiconductor device and a method for producing a semiconductor device are disclosed. The semiconductor device includes a first silicon layer; a first dielectric layer, located on the first silicon layer, where the first dielectric layer includes a window, and a bottom horizontal size of the window of the first dielectric layer is not greater than 20 nm; and a III-V semiconductor layer, located on the first dielectric layer and in the window of the first dielectric layer, and connected to the first silicon layer in the window of the first dielectric layer. A III-V semiconductor material of the semiconductor device has no threading dislocations, and therefore has relatively high performance.

Abstract: Embodiments described herein generally relate to a wave guide and a method of creating a wave guide. In one embodiment, a method of forming a wave guide is disclosed herein. An inverse master substrate having a plurality of projections extending therefrom is formed. A high refractive index material is formed on a top surface of the inverse master substrate. A glass layer is positioned on a top surface of the high refractive index material. The inverse master substrate is removed from the high refractive index material.

Abstract: A length of a coating on an optical fiber is cut and stripped from an end of the fiber by supporting the fiber in confronting relation to a cutting edge on one or more blades. Each blade is positioned so that its cutting edge cuts into the coating without delaminating the coating from an underlying fiber cladding by providing the cutting edge with sufficient sharpness. The coating is sliced around the circumference of the fiber by either rotating the fiber about its axis so that the cutting edge of each blade slices the coating around a corresponding portion of the circumference of the fiber, or rotating the cutting edge of each blade about the fiber axis so that the cutting edge slices the coating around a corresponding portion of the circumference of the fiber. A cut length of the coating is then removed from the end of the fiber.

Abstract: The present invention relates to optical coupling systems that employ a multicore optical fiber. The system can be employed with two multicore optical fibers or with a single multicore optical fiber for use with an optical device. In particular, the system includes connectors having a lens assembly configured to relay optical signals and a ferrule to position the lens assembly. Additional details for making and using such systems are described herein.

Abstract: A four-dimensional multiplexing method and four-dimensional multiplexing system are provided for optical networks. The method includes receiving sensor data to be transmitted on an optical network. The method also includes encoding the sensor data into an optical signal employing one or more multiplexing systems. The method additionally includes transmitting the optical signal over the optical network. The method further includes decoding the optical signal into the sensor data employing the one or more multiplexing systems. The method also includes controlling an operation of a processor-based machine responsive to the sensor data.

Abstract: A cable breakout assembly includes: a cable including a plurality of signal-carrying members enclosed in a protective jacket; a plurality of connector modules, each of the connector modules having at least one side wall and a connector mounted thereto, wherein the connector modules are arranged in serial relationship along an axis, with a gap between adjacent connector modules; and at least one flex member extending between the connector modules that substantially prevents the axial spacing of the gaps between adjacent connector modules from increasing, but enables adjacent connector modules to flex about the axis relative to each other. Each of the signal carrying-members is connected with a respective connector.

Abstract: A connector comprising: (a) shell acing a cavity configured to receive a single conventional insert (b) one or more modular inserts, each modular insert having a form factor ½ to ¼ of the form factor of said conventional insert, such that said cavity is capable of receiving 2 to 4 said modular inserts; (c) said each modular insert having at least: (i) a housing having a front opening and a rear opening, (ii) an interface disposed in said front opening, said interface presenting one or more conductors, said conductors extending from said interface rearward through said rear opening and into a jacketed cable, (iii) a crimp portion rearward of said rear opening, said jacketed cable being secured to said crimp portion, and (iv) one or more seals sealing said front and rear opening such that said interior of said housing is sealed from environment.

Abstract: A compact adapter module for installation at customer premises includes a base for mounting on a supporting surface, and a cover. The base is constructed for mounting a connector adapter operative to connect two communication lines to one another at a given location along a routing path at customer premises. A cover protectively encloses the adapter and connectors mated to the adapter which terminate the lines. Space inside the covered module is limited substantially for storing only the adapter and mated connectors, so the module is compact in size and unobtrusive when mounted at the given location. The lines are received at two ports of the module, and an edge of the base is flush with the supporting surface at each port so the lines can be adhered directly to the supporting surface at the ports. Any adverse visual impact of the lines at the module is therefore minimized.

Abstract: A fiber optic cable and connector assembly is disclosed. In one aspect, the assembly includes a cable optical fiber, an optical fiber stub and a beam expanding fiber segment optically coupled between the cable optical fiber and the optical fiber stub. The optical fiber stub has a constant mode field diameter along its length and has a larger mode field diameter than the cable optical fiber. In another aspect, a fiber optic cable and connector assembly includes a fiber optic connector mounted at the end of a fiber optic cable. The fiber optic connector includes a ferrule assembly including an expanded beam fiber segment supported within the ferrule. The expanded beam fiber segment can be constructed such that the expanded beam fiber segment is polished first and then cleaved to an exact pitch length. The expanded beam fiber segment can be fusion spliced to a single mode optical fiber at a splice location behind the ferrule.

Abstract: A ferrule includes a ferrule body having a first opening formed in a side face thereof, and having a second opening formed in a top face thereof, wherein the first opening is configured to receive an optical waveguide inserted into the ferrule body at the side face, and wherein the second opening is formed over and in communication with the first opening, such that the second opening connects an inner space of the first opening to an outside of the ferrule body.

Abstract: A pressing cleaner for an optical connector's end face includes a housing, a support unit fixed inside the housing, a feeding unit which is opposite to the support unit and held and moved in the housing; the feeding unit is pivotally fitted at a rotary unit ahead, the rotary unit is provided with a cleaning head at the front side, the cleaning head is equipped with a pressing surface ahead, and the feeding unit allows a cleaning wire to be stretched and wound around the cleaning head as well as the pressing surface externally; the rotary unit includes a worm shaft on which guiding slots are opened wherein the guiding slots correspond to pins in the front of the support unit for holding the pins inside the guiding slots; an optical connector's end face is cleaned by the cleaning wire when the pressing surface is activated and the rotary unit is driven via the pins and the guiding slots for rotations.

Abstract: An optical connector includes a first connector and a second connector configured to be mated to the first connector. The first connector includes a plate having an opening, a substrate stacked on the plate, and an adapter having an opening and connected to the plate. The second connector includes a housing and a ferrule configured to connect to an optical fiber. The ferrule is provided in the housing to project from the housing to have an end of the ferrule exposed outside the housing. The ferrule is inserted in the openings when the first connector and the second connector are mated together.

Abstract: In-line sealed adapter tubes configured to seal non-hardened connectors when connected with hardened connectors such as an outdoor rated connectors. An adapter tube for sealing a non-hardened connector comprises an adapter body having a first end and a second end opposite the first end. The adapter tube further comprises a first adapter endcap configured to couple to the first end and further configured to receive a hardened connector. The adapter tube further comprises a second adapter endcap configured to couple to the second end and further configured to receive a non-hardened connector for coupling to the hardened connector, such that the non-hardened connector is disposed within the adapter body.

Abstract: Methods and systems for a multi-fiber push-on/pull-off connector locking clip are disclosed and may include operatively coupling a multi-fiber push-on/push-off (MPO) connector to an MPO adaptor by inserting the MPO connector into the MPO adaptor, where the MPO connector comprises an MPO connector pull-to-release housing. The MPO connector may be secured to the MPO adaptor by placing an MPO locking clip adjacent to the MPO connector pull-to-release housing, thereby preventing the MPO connector pull-to-release housing from being actuated. An optical cable may be coupled to the MPO connector. The adaptor may be coupled to an optical device, which may include an optical transceiver. The MPO locking clip may be plastic or metal. The MPO connector and the MPO connector pull-to-release housing may be plastic.

Abstract: An optical connector includes a substrate, plural optical channels for transmitting an optical signal, a light source, an oblique structure, and a photo detector. The light source is located on the substrate to emit a first optical signal. The oblique structure has an optical reflective surface to reflect the first optical signal emitted by the light source to at least one of the optical channels. The photo detector is located on the substrate to receive a second optical signal emitted by at least one of the optical channels. The optical reflective surface has at least one gap, such that the optical reflective surface is divided into at least two segments by the gap, and the segments are not electrically connected with each other.

Abstract: The optical-electrical printed circuit board disclosed herein includes a waveguide link assembly and a printed circuit board assembly. The printed circuit board assembly has first and second PCB layers between which optical waveguides of the waveguide link assembly are disposed. The end faces the optical waveguides are accessible through an access aperture in the printed circuit board assembly. An optical interconnector can be used to optically connect the optical waveguides to waveguides of an optical-electrical integrated circuit operably disposed on the printed circuit board assembly to form a photonic device. A waveguide bending structure can be used to bend the optical waveguides to facilitate optical coupling to the optical interconnector or directly to the waveguides of the optical-electrical integrated circuit. Methods of forming an optical-electrical printed circuit board, a photonic assembly and a photonic device are also disclosed.

Abstract: A variation in coupling ratio of output light from a laser element to an optical fiber is suppressed. A semiconductor laser module including a plurality of semiconductor laser elements, an optical fiber, a condenser that condenses a laser beam emitted from each of the semiconductor laser elements to the optical fiber, and a housing that implements the laser elements, the condenser, and the optical fiber includes at least one thin plate that is arranged between the laser elements and a top of the housing, and arranged on the top to form a gap with the top.

Abstract: Methods and systems for a photonically enabled complementary metal-oxide semiconductor (CMOS) chip are disclosed. The CMOS chip may comprise a plurality of lasers, a microlens, a turning mirror, and an optical bench, and may generate optical signals utilizing the lasers, focus the optical signals utilizing the microlens, and reflect the optical signals at an angle defined by the turning mirror. The reflected optical signals may be transmitted into the photonically enabled CMOS chip, which may comprise a non-reciprocal polarization rotator, comprising a latching faraday rotator. The CMOS chip may comprise a reciprocal polarization rotator, which may comprise a half-wave plate comprising birefringent materials operably coupled to the optical bench. The turning mirror may be integrated in the optical bench and may reflect the optical signals to transmit through a lid operably coupled to the optical bench.

Abstract: An optical termination box comprising: a tubular housing (10) with an open end (10b) and a closed end (10a) provided with an input opening (11) for an optical distribution cable (100); a cover (20) securable against the open end (10b) of the housing (10) and pierced by output adapters (30); and an optical fiber accommodating tray (40), internal to the tubular housing (10) and having a first end (41) carrying a tubular bushing (50) with a base portion (51) seated against the closed end (10a) of the tubular housing (10), and a projecting body portion (52) out of the input opening (11), to cooperate with a puller (60) that holds the tubular bushing (50) hermetically pressed against the closed end (10a) of the tubular housing (10). The tubular bushing (50) hermetically receives and retains an end portion (100a) of an optical distribution cable (100) containing at least one optical fiber (FO).

Abstract: A fiber optic enclosure assembly includes a housing having an interior region and a bearing mount disposed in the interior region of the housing. A cable spool is connectedly engaged with the bearing mount such that the cable spool selectively rotates within the housing. A termination module disposed on the cable spool so that the termination module rotates in unison with the cable spool. A method of paying out a fiber optic cable from a fiber optic enclosure includes rotating a cable spool, which has a subscriber cable coiled around a spooling portion of the cable spool, about an axis of a housing of the fiber optic enclosure until a desired length of subscriber cable is paid out. A termination module is disposed on the cable spool.

Abstract: A device to be inserted into a conduit includes at least one tube intended to receive optic fibers or micro fiber optic cables therein. A jacket surrounds the tube. In an embodiment where there are a plurality of tubes, they are loosely aligned within the jacket. In another embodiment, opposed surfaces of the jacket are attached to each other to form compartments for each tube. In still another embodiment, the jacket holds the tubes generally in a bundle. The jacket of a tube may also be attached to one or more innerducts, each of which can receive a fiber optic cable. Alternatively, an innerduct may be attached to two jackets each of which carry a tube therein.

Abstract: A lens barrel that achieves modes with and without an optical element while reducing a size in an optical axis direction. A first drive mechanism moves a first optical element in the optical axis direction. A second optical element is located at an image surface side of the first optical element and is selectively inserted in an optical path. A second drive mechanism moves a holding member that holds the second optical element in a direction different from an optical axis. A control unit controls the first drive mechanism to move the first optical element to an object side to a position where the first optical element and the holding member are not in an overlap state when viewing in a direction perpendicular to the optical axis, controls the second drive mechanism to remove the second optical element from the optical path, when they are in the overlap state.

Abstract: An optical lens assembly includes a first lens element and a second lens element. The first lens element has at least one contacting surface. The second lens element has at least one contacting surface. The contacting surface of the first lens element comes in contact with the contacting surface of the second lens element, and at least one air duct is disposed on at least one of the contacting surface of the first lens element and the contacting surface of the second lens element.

Abstract: Provided are a zoom lens device and a method for controlling the device, capable of reducing astigmatism regardless of the position of the zoom lens. In accordance with a zoom command, a lens constituting a zoom optical system is moved in the direction of the optical axis (step 81). The position of the moved lens is detected (step 82), and an amount of rotation corresponding to the detected position of the moved lens is read from a table that is stored (step 83). The lens is rotated by the read amount of rotation (step 84). As a result of the rotation of the lens, astigmatism in the zoom optical system is reduced.

Abstract: In the case in which a plurality of regions which is obtained by dividing an image region of the image data is set as partial regions, a controller detects focus positions respectively with respect to the partial regions and moves a focus lens to each of the detected focus positions to capture a video. The controller has, as a video capturing method for the video capturing, a first method in which the video capturing is performed with the focus lens stopped at each of the focus positions, and a second method in which the video capturing is performed with the focus lens being moved without stopped at each of the focus positions.

Abstract: A lens assembly comprises sequentially from an object side to an image side along an optical axis a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. The first lens is a meniscus lens with negative refractive power. The second lens is a meniscus lens with negative refractive power. The third lens is a biconvex lens with positive refractive power. The fourth lens is a biconvex lens with positive refractive power. The fifth lens is a biconcave lens with negative refractive power. The sixth lens is a biconvex lens with positive refractive power.

Abstract: Disclosed herein is an imaging lens suitable for a camera module using a high resolution imaging sensor, decreasing a flare phenomenon and reducing the sensitivity. The imaging lens comprises, orderly from the object side, a first lens having positive (+) refractive force; a second lens having negative (?) refractive force; a third lens having positive (+) refractive force; a fourth lens having positive (+) refractive force; and a fifth lens having negative (?) refractive force, wherein an object side plane of the third lens is convexly formed.

Abstract: A camera lens with a single optical axis includes a first lens having a positive refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, and a fifth lens having a negative refractive power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and an image sensor are arranged in sequence from an object side to an image side, where an axial distance between the third lens and the fourth lens is CT34, an axial distance between the fourth lens and the fifth lens is CT45, and the following condition is satisfied: 8.3<CT34/CT45<15.7.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The camera optical lens further satisfies specific conditions.

Abstract: An imaging lens assembly includes a plurality of lens elements, wherein at least one of the lens elements is a dual molded lens element. The dual molded lens element includes a light transmitting portion and a light absorbing portion. The light transmitting portion includes an effective optical section. The light absorbing portion is located on at least one surface of an object-side surface and an image-side surface of the dual molded lens element, wherein a plastic material and a color of the light absorbing portion are different from a plastic material and a color of the light transmitting portion, and the light absorbing portion includes an opening. The opening is non-circular and disposed correspondingly to the effective optical section.

Abstract: Compact folded lens systems are described that may be used in small form factor cameras. Lens systems are described that may include four lens elements with refractive power, with a light folding element such as a prism, located between a first lens element on the object side of the lens system and a second lens element, that redirects the light refracted from the first lens element from a first axis onto a second axis on which the other lens elements and a photosensor are arranged. The lens systems may include an aperture stop located behind the front vertex of the lens system, for example at the first lens element, and an optional infrared filter, for example located between the last lens element and a photosensor.

Abstract: An optical lens accessory used in conjunction with a terminal device equipped with two camera devices is provided, the optical lens accessory includes: an optical device including two fisheye lenses arranged in a back-to-back configuration, where directions of the two respective viewing angles associated with the two fisheye lenses are opposite to each other, and where viewing angle of each of the fisheye lenses is greater than 180° to allow each of the two fisheye lenses to independently frame a view in the respective direction of the respective viewing angle, to let the framed lights into the two camera devices; a housing device positioned outside the optical device, where the housing device is configured to support the optical device, and to isolate the framed lights from external stray light; and a fixture device configured to attach the optical lens accessory to the terminal device.

Abstract: A wide-angle lens includes a first lens group, a second lens group, and an aperture arranged in that sequence from object side to image side. The first lens group as a whole has a positive refractive power, and includes a first lens, a second lens, a third lens, and a fourth lens. The first lens has a negative refractive power. The second lens has a negative refractive power. The third lens has a negative refractive power. The fourth lens has a positive refractive power. The second lens group as a whole has a positive refractive power, and includes a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The fifth lens has a positive refractive power. The sixth lens has a negative refractive power. The seventh lens has a positive refractive power. The eighth lens has a positive refractive power.

Abstract: An image display device includes a high-performance projection zoom lens with a very wide field angle and an image display device including a projection zoom lens of a five-lens-group type, which achieves high performance across the entire zoom area. The image display device is configured to project an image onto a target projection surface and display a magnified image of the image, which uses a projection zoom lens having a five-lens-group configuration in which first to fifth lens groups G1 to G5 are arranged from the magnification side toward the reduction side, and each of the constituent lens groups or lenses included in the lens groups has a combination of negative and positive refractive powers, and in the lens configuration, focal lengths of the constituent lens groups, relative travel distances, lens distances to the image display element, and constituent lens shapes are properly selected.

Abstract: A variable magnification optical system comprises, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having positive refractive power; and a fifth lens group; upon varying magnification from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group being varied, the fifth lens group being moved with respect to the image plane; upon focusing the third lens group being moved along the optical axis; and the given conditional expressions being satisfied; thereby providing a small-size variable magnification optical system having a high variable magnification ratio and an excellent optical performance

Abstract: An image quality is improved although a medical stereomicroscope optical system and a medical observation apparatus are small and light. An objective optical system and a plurality of imaging optical systems are arranged in an order from an object side to an image side, and the imaging optical system has at least a single aspheric surface. Accordingly, a spherical aberration and a field curvature are improved, and the image quality is improved although the medical stereomicroscope optical system and a medical observation apparatus are small and light.