Abstract: There is provided a thin film reflector, a method and an ALD-system for producing the thin film reflector. The method includes the steps of providing a substrate including at least one type of material, and providing a thin film including a metallic compound on at least part of the substrate. The method also includes the step of coating at least part of the thin film with a first barrier layer by applying Low Temperature Atomic Layer Deposition with at least one first material, and the step of providing a second barrier layer on at least part of the first barrier layer by applying High Temperature Atomic Layer Deposition, with at least one second material to thereby obtain a multi-layered thin film reflector. There is also an ALD control system for controlling the ALD-system. There is furthermore provided a computer program for controlling the temperature to be used by an ALD-tool.

Abstract: A method of manufacturing a microarray lens having a plurality of microlenses includes preparing a substrate having a plurality of depressions on a side, and forming a lens layer corresponding to shapes of the depressions by depositing a lens raw material on the side of the substrate on which the depressions are formed. The method is able to form a plurality of depression in precise aspheric shapes on a substrate and to easily adjust or change the number and the gaps of lenses by forming depressions on a substrate using a probe and depositing a lens layer on the substrate with the depressions.

Abstract: A vortex beam device includes: a metal reflector, a low refractive index layer, and multiple elliptical dielectric elements. The low refractive index layer located on the metal reflector. The multiple elliptical dielectric elements are embedded in the low refractive index layer and arranged in an array, major axes of the multiple elliptical dielectric elements are parallel or coincident. The multiple elliptical dielectric elements have a same thickness. A thickness of the low refractive index layer is greater than a thickness of the elliptical dielectric element. An outer surface of each elliptical dielectric element is flush with an outer surface of the low refractive index layer. A refractive index of the low refractive index layer is less than a refractive index of the elliptical dielectric element.

Abstract: A display module includes a bottom substrate, a display device having a plurality of display pixels, and a diffusion module. The display pixels are disposed between the bottom substrate and the diffusion module. The diffusion module has a thickness and a haze, wherein the haze of the diffusion module satisfies: A < Haze ? ( % ) < B ; wherein A = 0.642 × ( NP ) 0.35 ( NT ) 0.32 ; B = 0.821 × ( NP ) 0.45 ( NT ) 0.60 ; NP = 25400 / PPI 63 ? ? µm ; and NT = T 500 ? ? µm ; wherein PPI is a resolution of the display module, T is the thickness of the diffusion module, and Haze is the haze of the diffusion module.

Abstract: A composite glue coating device and a preparation method for a fancy reflective material using the same, which relates to the technical field of reflective material production. The composite glue coating device comprises a composite glue roller (1), a glue coating roller (2), a glue sink device (3) and a glue scrapping device (4). The composite glue roller (1) and the glue coating roller (2) are arranged as a clamping roller set and a bead planting film passing interval (L) is formed between the composite glue roller (1) and the glue coating roller (2). The glue scrapping device (4) is connected with a scraper of the glue coating roller (2). A plurality of glue moving grooves (5) are evenly distributed on the glue coating roller (2). The glue coating roller (2) is connected with the glue sink device (3) and is glue immersed.

Abstract: Metasurfaces comprise an array of pillars in a lattice. The dimensions of the pillars and the spacing are varied to obtain desired optical properties. The dispersionless metasurfaces can focus optical light over a broad wavelength range. Specific dispersion profiles for the metasurfaces can be designed. Gratings can be fabricated having similar properties as the array of pillars. Pillars in the metasurfaces can have different cross-section profiles.

Abstract: Color temperature actually emitted by a light emitting diode (LED) is perceived by a viewer of that LED to be altered because of the placement of a passive color temperature-shifting panel between the viewer and the LED. The panel is colored in a manner to cause a perception of a shift from one color temperature of the light emitting diode to another color temperature of the light emitting diode in the absence of any electrochromic, photochromic, or thermochromic material in the panel.

Abstract: A composition for an optical film including a liquid crystal, and polysiloxane including a structural unit represented by Chemical Formula 1A and a structural unit represented by Chemical Formula 1B: wherein, in Chemical Formulae 1A and 1B, groups L1, L2, R1, R2, X, and Y are the same as in the detailed description.

Abstract: An optical film includes a first compensation film and a second compensation film having a retardation for incident light different from the first compensation film, wherein the first compensation film includes a first liquid crystal layer including liquid crystals which are obliquely tilted relative to a surface of the first compensation film, and the second compensation film has a refractive index satisfying Relationship Equation 1 and Relationship Equation 2.

Abstract: We describe a window assembly comprising: a window pane comprising a glass or plastic sheet; and a layer of holographic recording medium attached to said glass or plastic sheet; wherein said layer of holographic recording medium has recorded within the medium a volume hologram configured to direct light incident onto said glass or plastic sheet to propagate within a thickness of said glass or plastic sheet. In embodiments the volume hologram is fabricated by recording a transmission hologram and shrinking the recorded hologram to convert the transmission hologram to an edge-directing hologram configured to direct light in a direction to be totally internally reflected within the window pane, for example at greater than 40°, 50°, 60°, 70°, 75° or 80° to a normal to the surface of the hologram.

Abstract: Systems, devices, and methods for making, replicating, and using curved holographic optical elements (“HOEs”) are described. A hologram may be optically recorded into a planar layer of holographic film with various measures in place to compensate for changes (e.g., in optical power and/or playback wavelength and/or angular bandwidth) that may result when a curvature is subsequently applied thereto. A hologram may be optically recorded into a curved layer of holographic film with various measures in place to compensate for optical effects of a curved transparent substrate upon which the holographic film is mounted. A curved HOE may be returned to a planar configuration to undergo holographic replication or holographic replication may be performed using a curved master HOE and curved “recipient” film. The curved HOEs described herein are particularly well-suited for use when integrated with a curved eyeglass lens to form the transparent combiner of a virtual retina display.

Abstract: A luminaire comprises an optical element. The optical element comprises a coupling portion that comprises a coupling cavity that extends along a length of the optical element. The coupling cavity is configured to receive at least one light emitting diode. The optical element further comprises first and second sections extending away from the coupling portion of the optical element along the length of the coupling cavity. The first section comprises a first thickness closer to the coupling portion and a second thickness further from the coupling portion. The first thickness is greater than the second thickness. The second section comprises a third thickness closer to the coupling portion and a fourth thickness further from the coupling portion. The third thickness is greater than the fourth thickness. Light is extracted out of extraction features of opposing sides of at least one section.

Abstract: The present disclosure concerns a lighting device (100) comprising a light source (1) and a light guide plate (2). The light guide plate (2) is disposed at a distance (D1) from the emitter surface (1a) with an air gap (3) therebetween. A side reflector (4) surrounds the emitter surface (1a) of the light source and bounds the gap (3) between the emitter surface (1a) and the light entry surface (2a). The side reflector (4) comprises a tapered reflection surface (4a) adjacent the emitter surface (1a) and facing the light entry surface (2a). The tapered reflection surface (4a) is disposed at a tapering angle (?) towards the light entry surface (2a). The tapering angle (?) is configured such that any light emitted by the emitter surface (1a) within the opening angle (?) of the light source (1) is not reflected by the reflection surface (4a) before being received for the first time by the light entry surface (2a).

Abstract: A display device is disclosed. The display device includes a display panel, a light guide plate located in a rear of the display panel, a light assembly located on a side of the light guide plate and providing the light guide plate with light, and a light absorbing portion formed on a back surface or a front surface of the light guide plate and absorbing the light provided by the light assembly in a predetermined wavelength range.

Abstract: A light guide includes a front surface. A back surface is opposite the front surface and includes a depression. A light incident surface introduces light. The light reflects off the depression and is emitted through the front surface. The depression includes an inclined side surface that faces the light incident surface. The inclined side surface includes a reflective curved surface that includes at least 50% of a surface area of the inclined side surface. In a cross section view of the depression in a plane substantially orthogonal to the front surface, a first tangent that touches a curved line defining the reflective curved surface of the inclined side surface and a second tangent that touches the curved line in a different location than the first tangent form a first angle that is greater than or equal to 0° and less than or equal to 30°.

Abstract: An illumination system employing a waveguide that receives and propagates light in response to transmission and total internal reflection. Light deflecting elements distributed along the propagation path incrementally change the out-of-plane angles of light rays and cause decoupling of portions of light from the waveguide at different distances from the light input edge or end. Light may escape from the waveguide into an intermediate layer at low out-of-plane angles and can be further redirected by light extraction features out of the system. In one embodiment, the illumination system is configured to emit collimated light. In one embodiment, the illumination system includes shallow surface relief features. In one embodiment, the light deflecting elements include forward-scattering particles distributed throughout the volume of the waveguide.

Abstract: A backlight module includes a lamp set, a light guiding plate, a diffuser, a top prism sheet, and a down prism sheet. The diffuser includes a first end and a second end opposite to each other, the first end of the diffuser is closer to the lamp set than the second end, and the diffuser includes a first end and a second end opposite to each other. The diffuser includes the overlapped portion stacked with the top/down prism sheets and the extended portion extending from the overlapped portion. On the first end of the diffuser, the light beams emitted by the light guiding plate may be processed by the first extended portion, instead of being emitted out directly. This can avoid the bright lines occurred by the backlit so as to reduce the optical leakage. In addition, a display device is also disclosed.

Abstract: A light source module, a display apparatus and a light turning film are provided. The light turning film includes a light incident surface and a light emitting surface. The light incident surface includes a plurality of first optical microstructures and a plurality of second optical microstructures, and is adapted to guide a light beam to enter the light turning film through the light incident surface. The light emitting surface is disposed opposite to the light incident surface, and is adapted to guide the light beam to leave the light turning film through the light emitting surface. The first optical microstructures and the second optical microstructures protrude outward from the light turning film with reference of a reference plane. Each of the first optical microstructures and each of the second optical microstructures are complied with predetermined conditions.

Abstract: A plastic frame is configured for fixing a backlight module generating a light source and for transmitting the light source to a panel. The plastic frame includes end surfaces for adhering adhesive-shading tape. The end surface is configured with an elastic protrusive portion. With such configuration, when the liquid crystal panel is pressed, the elastic protrusive portion operates as a buffer to absorb the shocks. In this way, the top and the down prism sheets, a diffuser sheet, or a light guiding plate are prevented from being crushed or scraped. In addition, a backlight module and a display device are also disclosed.

Abstract: A surface lighting assembly emitting light from a surface by making light from a light source incident to an incident end surface of a light guide plate is provided. The surface lighting assembly has a laminated body overlapping a diffuser sheet and an opaque plate on a surface of the light guide plate, a frame member arranging along an end edge of the laminated body, and a fastening member fixing the laminated body and the frame member in the thickness direction. The frame member is formed with U-shaped in cross section. In the first and second side surfaces, through holes are formed so as to insert the fastening member and guide it along the longitudinal direction of the frame member.

Abstract: A backlight module, a method of assembling the backlight module, and a display device are disclosed. The backlight module includes a fixing frame that has a light exit and a side plate provided with a first opening; an optical unit that is inserted into the fixing frame through the first opening and has a light emitting side opposite to the light exit; and a sealing piece that is engaged with the first opening to close the first opening. Embodiments of the present disclosure can reduce the manufacture difficulty and also material cost of the backlight module.

Abstract: A display device comprises a light source, an optical member, a display panel, and a frame. The frame supports the display panel. The frame has a first protruding portion that contacts with an area of a rear facing surface of the optical member within a predetermined distance from a center portion of the optical member. The first protruding portion has an overall rectangular shape with a step part at at least one corner of the overall rectangular shape.

Abstract: A display device comprises a display panel, a light source, an optical member, and a frame. The optical member reflects light from the light source towards the display panel. The frame has a protruding portion that supports the optical member and is disposed near a periphery of the display panel.

Abstract: Examples of structurally supportive backlight systems and devices incorporating such backlight systems are disclosed. One disclosed example provides a backlight system comprising a reflector, a light guide comprising a glass sheet, the glass sheet being adhered to the reflector with adhesive light extracting features, and a light source positioned to direct light into the light guide.

Abstract: A silicon photonic platform includes a substrate supporting a buried oxide layer, an active silicon layer deposited on the buried oxide layer, a first silicon nitride layer separated from the active silicon layer by a first spacer, the first silicon nitride layer and the active silicon layer constituting a first light-transferring interlayer transition and a second silicon nitride layer covered by a cladding and separated from the first silicon layer by a second spacer, the second silicon nitride layer and the first silicon nitride layer constituting a second light-transferring interlayer transition. The second silicon nitride layer passes over one or more waveguides in the active silicon layer to thereby define a waveguide crossing. The silicon nitride layers may be substituted with an equivalent dielectric with a similar refractive index and high optical transparency in the desired operating wavelength range.

Abstract: Disclosed is a waveguide polarizing optical device, including a first waveguide polarizer (6), a section of a second optical waveguide (31) and a second thin-plate polarizer (52) having a physical thickness T and a refractive index n, the second thin-plate polarizer (52) being disposed on the optical path between a waveguide end (8) of the first polarizer (6) and one end (32) of the second optical waveguide (31), the physical distance d between the waveguide end (8) of the first polarizer (6) and the end (32) of the second optical waveguide (31) being less than or equal to twice the Rayleigh length and the physical thickness T of the second polarizer (52) being less than or equal to the physical distance d.

Abstract: There is provided a semi-circular resonator using a whispering gallery mode (WGM) and an optical sensor using the same. Accordingly, an active region that is a waveguide of an active layer in which laser oscillation is caused by gains of advancing beams is deeply etched in a semi-circular or semi-ring shape.

Abstract: An optical coupler has a plastic optical fiber and a curved support member for mechanically supporting the plastic optical fiber at a predetermined bend radius. The plastic optical fiber can be made of perfluorinated polymer. The plastic optical fiber can be curved at a bend radius of less than 10 mm. This enables compact packaging of the coupler.

Abstract: A connector (1), in particular cable connector, for producing an optical and electrical connection to a mating connector (2). The connector (1) has a connector main housing (3) and at least one housing attachment part (4) and at least one optical waveguide carrier (5), and the housing attachment part (4) is fastened or fastenable releasably to the connector main housing (3) by a releasable and reconnectable connecting device (6). The optical waveguide carrier (5) and at least one electric contact (7) are arranged on the connector main housing (3), and the housing attachment part (4) has at least one electric extension contact (8) which is connectable to the electric contact (7) of the connector main housing (3) by connection of the housing attachment part (4) to the connector main housing (3).

Abstract: A fiber optic adapter including a housing, a deflectable member and a locking member. The housing has a longitudinal passage extending between a first opening at a first end of the housing and a second opening at a second end of the housing, and the housing is sized to fit within a fiber optic receptacle. The deflectable member is in the longitudinal passage of the housing and configured to retain a fiber optic terminus in the housing. The locking member is interfaced with the housing and is sized to fit within a retaining notch in the fiber optic receptacle to prevent separation of the housing from the receptacle. The adapter may be an in-line embedded adapter that does not introduce optical loss to optically and mechanically couple an LC receptacle and a terminus.

Abstract: An optical adapter includes: a housing having a plurality of openings on each of opposite end surfaces thereof; a plurality of ports formed in parallel with each other inside the housing and each extending to form one of the openings on each of the opposite ends surfaces, an optical connector being inserted into each of the openings; and a shutter part installed at each of the ports such that when the optical connector is inserted into an opening of one end of the port, the shutter part leans back to a retreat position that passes light emitted from the optical connector inserted into an opening of another end of the port, when the optical connector is pulled out of the opening of the one end of the port, the shutter part is raised up from the retreat position to a blocking position that blocks the emitted light.

Abstract: Disclosed are optical connectors having lenses along with methods for making the same. In one embodiment, the optical connector includes a fiber body having a front portion with a plurality of fiber guides, and a connector body having a plurality of connector body fiber guides that lead to a plurality of lenses at a front portion of the connector body. The fiber body attaches to the connector body and may align a plurality of optical fibers to the lenses at the front portion of the connector body. One embodiment has the fiber body configured as a crimp body with a barrel at a rear portion for attaching a fiber optic cable.

Abstract: The present disclosure provides an optical fiber connector, comprising an integrated ferrule assembly and an integrated outer housing assembly, the ferrule assembly being adapted to be fitted into the housing assembly. The ferrule assembly at least comprises an inner housing, a spring, a multi-hole ferrule, a multi-fiber optical cable, a sleeve and a thermal shrinkable tube. The housing assembly at least comprises an outer housing, an outer tail tube and an outer protection cap.

Abstract: A fiber optic connector and cable assembly is disclosed. The assembly includes a fiber optic connector and a fiber optic cable. The fiber optic cable can be coupled to the assembly at a demarcation section. All components of the fiber optic cable (e.g., fiber, strength members, jacket, etc.) are fixed relative to each other and relative to the fiber optic connector at the demarcation section. The demarcation section may be located on a boot mounted at a proximal end of the fiber optic connector. For example, the demarcation section may be located at a proximal end of the boot. The boot may include an inner passage extending from the demarcation section to the connector, and exterior slots which do not connect to the inner passage.

Abstract: Various connector housings for securing an optical cable, as well as methods of use and manufacture thereof are disclosed. A single-piece unitary connector housing body may include a first opening formed in a first end of the housing body, a second opening formed in a second end of the housing body, a bore through the housing body extending from the first opening to the second opening, and a back post surrounding the second opening. The first opening may be configured to receive a terminating optical cable and the second opening may be configured to receive a fiber optic cable. The back post may extend from the second opening in a longitudinal direction and may include a plurality of protrusions thereon. A length of the back post may have a concave shape.

Abstract: A pluggable optical transceiver implementing a pull-tab is disclosed. The pull-tab includes arms assembled with a body of the optical transceiver and a holder connecting the arms. The holder, which is provided in ends of the arms, provides a tab and a bridge, where the tab and the bridge form a space where an optical fiber mated with the optical transceiver is secured. The tab is dynamically engaged with the bridge after the optical fiber is set on the bridge.

Abstract: Reduced-profile connection components are described. The reduced-profile connection components are configured to connect various data transmission elements, including cables, network devices, and computing devices. A non-limiting example of a connection component includes a fiber optic connection component, including connectors, adapters, and assemblies formed therefrom. In some embodiments, the connection components may include mechanical transfer (MT) and multi-fiber push-on/pull-off (MPO) connection components, such as MT ferrules and MPO adapters. The reduced-profile connection components configured according to some embodiments have a smaller profile and/or require less parts to achieve a connection compared to conventional connection components. In some embodiments, the reduced-profile connection components may be used with conventional connection components. For example a reduced-profile connector may use a conventional MT ferrule to establish a connection within a conventional MPO adapter.

Abstract: The present disclosure relates to an optoelectrical connector module comprising a flexible circuit board (10) having a first region and a second region and a printed circuit board (PCB) (20) that is attached to the first region of the flexible circuit board, and an optical module (30) that is attached to the second region of the flexible circuit board. The optical module is configured to transmit and/or receive light signals. The optoelectrical connector module comprises further a rigid support structure (40) having a first and a second surface that enclose a defined angle. The first surface of the rigid support structure is thereby arranged in parallel to the PCB and the second surface of the rigid support structure is connected to the flexible circuit board opposite the second region.

Abstract: An optical bench including a substrate having a trench with the trench having an angled sidewall on which a reflective coating is provided. The optical bench also includes a first device and a waveguide positioned within the trench, a second device optically connected to the first device, and at least one active circuit electrically connected to the first device with the waveguide being positioned optically between the first device and the reflective coating. The optical bench also includes an optically transparent material that forms a first interface with the first device and a second interface with a first surface of the waveguide.

Abstract: An optical device includes a first optical component having a first optical axis and a second optical component having a second optical axis. The first optical component is mounted on the second optical component. No adhesive is between the first optical component and the second optical component. The first optical component has two opposite side surfaces which cover the second optical component and each have a row of laser welding spots formed thereon. A collimation error between the first optical axis and the second optical axis is not greater than 0.5 micrometer.

Abstract: An optical receiver module that recovers signals from a wavelength multiplexed optical signal is disclosed. The optical receiver module includes photodiodes (PDs) arranged in an array by a pitch, an amplifier that integrates trans-impedance amplifiers (TIAs) each corresponding to the PDs, and a sub-mount that mounts the PDs thereon. The sub-mount provides metal patterns on which the PDs are mounted by the flip-chip bonding. The metal patterns compensate a difference between the pitch of the arrayed PDs and another pitch of the TIAs in the amplifier as maintaining the characteristic impedance thereof substantially equal to each other.

Abstract: The present disclosure relates to systems and method for deploying a fiber optic network. Distribution devices are used to index fibers within the system to ensure that live fibers are provided at output locations throughout the system. In an example, fibers can be indexed in multiple directions within the system. In an example, spare ports can be providing in a forward direction and reverse direction ports can also be provided.

Abstract: Provided is a lens unit, which includes a lens barrel and a lens. The lens barrel includes a wall portion, which extends in the first direction. The wall portion includes at least two first inclined portions and at least two second inclined portions. A distance from each first inclined portion to a central axis CX is decreased as the first inclined portion extends to the first direction. A distance from each second inclined portion to the central axis CX is increased as the second inclined portion extends to the first direction. The lens is held in the wall portion by the first inclined portions and the second inclined portions.

Abstract: A follow focus, comprising a main bridge including a transmission housing and an output gear, a removable arm including an input gear and a lens turning gear or an interface capable of receiving a lens gear, an axial securement means that is operable by hand to engage to prevent axial movement between the arm and the transmission housing, and disengages to allow the arm to be rotated and/or removed, such that between the arm and the main bridge there is provided a first engagement element having a substantially axial face having projections and a second engagement element substantially axial face having corresponding indentations, wherein either the first or the second engagement element has a threaded outer circumference and may be fixably rotated, and wherein the first engagement element is borne by the arm, and the second engagement element is borne on the transmission housing such that the axial securement means may be operated to secure the arm to the main bridge so that the projections and corresponding

Abstract: Techniques are disclosed for systems and methods to provide concomitant mechanical motion inhibition and electrical distribution for actuator modules, such as microelectromechanical systems (MEMS) based optical actuators adapted to move and/or orient one or more lenses and/or optical devices of a camera module. A mechanical motion inhibition and electrical distribution system may include one or more flexible snubber structures disposed substantially adjacent a MEMS structure and between the MEMS structure and another component of a camera module. Each flexible snubber structure may be implemented with one or more electrical traces, flexible films, snubber films, and/or mechanical stabilizers adapted to route electrical signals to or from the MEMS structure and/or to inhibit mechanical motion of at least a portion of the MEMS structure.

Abstract: A lens barrel includes: a base frame having a first through-hole; an adhesion plate having a second through-hole; a lens frame disposed within the base frame; and an adhesively fixing portion fixing the lens frame to the base frame, wherein the adhesion plate is disposed in a vicinity of the first through-hole and movably held by the base frame, the lens frame includes a projection projecting radially relative to an optical axis of the lens barrel, the projection being engaged with the second through-hole and inserted in the first through-hole, the projection is movable within the first through-hole so as to change a position of the lens frame relative to the base frame, and the adhesively fixing portion is disposed in the first through-hole.

Abstract: Disclosed is an adjustable mirror mount that is capable of adjusting a mirror in two axes with a high degree of precision and low cross-coupling. Long horizontal and vertical adjustment arms are used to allow the precision adjustment about both a horizontal axis and a vertical axis.

Abstract: Methods and apparatuses for focus hunting prevention for phase detection auto focus (AF) are disclosed. In one aspect, the method is operable by an imaging device, for preventing focus hunting during a phase detection AF process. The method may include capturing an image of a scene and generating a phase difference value and a confidence level for the phase difference value based on the image. The method may also include calculating a focus hunting metric based at least in part on the phase difference value and the confidence level. The method may further include preventing focus hunting via at least one of preventing the start of the focus search and terminating the focus search, in response to the focus hunting metric meeting or exceeding a defined threshold value.

Abstract: A reconnaissance objective lens used for an unmanned aircraft, the reconnaissance objective lens comprising a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4) and a fifth lens (L5) successively and coaxially arranged along the transmission direction of incident light rays. The first lens (L1) is a biconvex lens, the second lens (L2) is a biconcave lens, the third lens (L3) is a meniscus lens, the fourth lens (L4) is a meniscus lens, and the fifth lens (L5) is a meniscus lens. The first lens (L1) and the second lens (L2) are glued to one another, and the fourth lens (L4) and the fifth lens (L5) are glued to one another.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens includes a negative refractive power, and the second lens includes a negative refractive power. The third lens includes a positive refractive power, and the fourth lens includes a positive refractive power, an object-side surface thereof being concave. The fifth lens includes a positive refractive power. The sixth lens includes a negative refractive power. The first to sixth lenses are sequentially disposed from an object side toward an imaging plane. One lens of the first to sixth lenses is cemented to a lens adjacent thereto.