Abstract: Various embodiments include spectrometers comprising diffraction gratings monolithically integrated with other optical elements. These optical elements may include slits and mirrors. The mirrors and gratings may be curved. In one embodiment, the mirrors are concave and the grating is convex. The mirrors and grating may be concentric or nearly concentric.

Abstract: A diffractive optical element includes stacked first and second diffraction gratings made of different materials. The materials of the first and second diffraction gratings are glass. The first and second diffraction gratings have grating surfaces contacted to each other. The materials satisfy a predetermined condition when Tg2 and At2 are a transformation point temperature and a yield point temperature of the material of the first diffraction grating, and Tg3 and At3 are a transformation point temperature and a yield point temperature of the material of the second diffraction grating.

Abstract: A tunable light filter has a transparent plate, a first mirror surface coupled to the transparent plate, and a base spaced from the transparent plate and defining a flexible base region. The flexible base region has at least one cell and a membrane coupled over the at least one cell. The flexible base region also has a second mirror surface coupled to the membrane. The tunable light filter also has an actuator which can move the second mirror surface relative to the first mirror surface. Methods of manufacturing a tunable light filter are also discussed.

Abstract: An optical filter including a bump, a first conformal transflective film, a conformal space layer and a second conformal transflective film is provided. The bump has a surface, wherein different areas of the surface have different normal vectors, respectively. Moreover, the first conformal transflective film is disposed on the surface of the bump, while the conformal space layer is disposed on the first conformal transflective film. Besides, the second conformal transflective film is disposed on the conformal space layer. By modulating the thickness of the conformal space layer, different colors is shown after the light is processed by the first conformal transflective film, the conformal space layer and the second conformal transflective film. The optical filter has the advantages of high color saturation and high light transmittance. Furthermore, the optical filter can mitigate color washout phenomenon appeared under large viewing angle.

Abstract: An optical filter has a multilayer thin film comprising first to i-th layers stacked in alternate layers of high and low refractive indices on a transparent substrate. Respective odd-numbered layers (Sigh refractive index layers) and respective even-numbered layers (low refractive index layers) form repetitive sequences of layers each of which cyclically changes in optical thickness throughout the multilayer tin film. Each of k-th from-the-bottom alternate layers of high and low refractive indices has such an optical thicknesses as meet the following conditional expressions (1) and (2), concurrently: n×d=(.c/4)×[1+sin{(k?1)×}×.] ??(1) 0 . . . <1 ??(2) where .c is the center wavelength of reflection band, n is the ref ion index of the layer for the d-line, d is the physical thickness of the layer, . is a factor of a pitch angle represented by 2./the number of layers a one layer-stack, . is the rate of amplitude.

Abstract: An interference coating between a display and an intended viewing area that selectively absorbs incident optical energy in at least one first wavelength region and selectively transmits incident optical energy in at least one second wavelength region.

Abstract: An apparatus for illuminating a light valve (34) comprises at least one laser array (10) capable of emitting a plurality of radiation beams (40a, 40b, 40c), each radiation beam propagating along a first axis. A light pipe (20) comprises at least two reflecting surfaces being spaced apart and opposing each other to reflect light along the first axis. An input end (24) separation between the two planar reflecting surfaces (22) is positioned to receive the plurality of radiation beams. An output end (26) separation between the two reflecting surfaces is positioned to emit an output radiation (42b). At least one optical element is located downstream of the output end separation and is operable for illuminating the light valve by imaging a portion of the output radiation onto the light valve. A random phase mask (150) is operable for creating a substantially uniform illumination profile in the output radiation.

Abstract: A display apparatus includes an image display unit having a plurality of pixels arranged on a predetermined curved surface; and a plurality of microlenses arranged on the predetermined curved surface such that they correspond to and face the plurality of pixels on the image display unit. Light rays that exit from the plurality of microlenses are collected into the eye so that a virtual image is placed at a position apart from the eye by at least a distance of distinct vision.

Abstract: A lenticular sheet, in one exemplary embodiment, includes a first surface having at least two portions, an opposing second surface, and a plurality of lenticular lenses formed in the first surface. Each portion of the first surface includes a number of lenticular lenses per centimeter that is different from the number of lenticular lenses per centimeter of an adjacent portion of the first surface.

Abstract: A curve representing a characteristic of a blue-light reflecting dichroic film DB and a curve representing a characteristic of a red-light reflecting dichroic film DR are configured to have shapes that track an ideal spectral characteristic of green. Accordingly, it is possible to obtain a characteristic approximated to the ideal spectral characteristic without using a trimming filter having a dichroic film in an exiting surface of a prism. Since it is not necessary to use the trimming filter having the dichroic film, it is possible to prevent ghost and flare from occurring due to the dichroic film of the trimming filter. Accordingly, it is possible to embody an imaging apparatus having the ideal spectral characteristic with ghost and flare being reduced.

Abstract: A controllable optical lens system, comprises a chamber housing first and second fluids, the interface between the fluids defining a lens surface. An electrode arrangement controls the shape of the lens surface and has first and second electrodes. A parameter is determined by the system dependent on the electrical resistance through at least one of the lens fluids between the first and second electrodes. Thus, the series resistance through a lens fluid is used as a measure of meniscus position.

Abstract: A projection objective of a microlithographic projection exposure apparatus comprises a manipulator for reducing rotationally asymmetric image errors. The manipulator in turn contains a lens, an optical element and an interspace formed between the lens and the optical element, which can be filled with a liquid. At least one actuator acting exclusively on the lens is furthermore provided, which can generate a rotationally asymmetric deformation of the lens.

Abstract: A zoom lens comprises: a stationary group that is stationary at the time of variable power; and a variable power group, disposed on an image side of the stationary group, that makes a variable power operation by moving in an optical axis direction at the time of variable power, wherein the stationary group comprises: a first lens group including a negative meniscus lens and a positive lens and having a positive refractive power as a whole; and a second lens group, disposed on the image side of the first lens group, including: a negative lens group including a negative meniscus lens and a positive lens; and a positive lens group including at least one positive lens, in order from an object side, the second lens group having a positive refractive power as a whole.

Abstract: A zoom lens comprises first, second, third and fourth lens groups in order from an object side, so as to change magnification by changing a spacing between the lens groups. The first lens group has a positive refractive power as a whole and comprises, in order from the object side, a negative meniscus lens, a reflecting member that bends an optical path nearly 90 degrees and a positive lens of a resin material having at least one aspheric surface. The second lens group has a negative refractive power as a whole and comprises a negative lens of a resin material on an most object side of the second lens group. A conditional expression given below is satisfied provided that P1 is a focal length of the positive lens of the resin material in the first lens group, and P2 is a focal length of the negative lens of the resin material in the second lens group. 1.0<|P1/P2|<3.

Abstract: A variable-power optical system includes, in order from an object side, first to fifth lens groups. The first and third lens groups are fixed at a time of varying magnification and at a time of focusing. The second, fourth and fifth lens groups are movable at the time of varying magnification. The first, third and fourth lens groups have positive refractive powers. The second and fifth lens groups have negative refractive powers. The fourth lens group has a focusing function. The following conditional expressions are satisfied. 0.4<fw/f1<0.8 0.5<|f2/fw|<0.8 where fw denotes a focal length of the whole system at an wide end, f1 denotes a focal length of the first lens group, and f2 denotes a focal length of the second lens group.

Abstract: An image projection optical system introduces light from an image-forming element by a zoom lens via an optical element. The optical element satisfies ?(Di×Ndi)/fw>4.0. The zoom lens includes, in order from a magnification side, first and second lens units, and lens units disposed closer to a reduction side than the second lens unit. The first lens unit is a negative lens unit. The lens units disposed closer to the reduction side than the second lens unit satisfy |dn/dt|<1.0×10?5. Magnification-side positive lens elements disposed closer to the magnification side than a negative lens element whose effective diameter is smallest in the lens units disposed closer to the reduction side than the second lens unit satisfy {9.0×?(1/fpA)+5.0×?(1/fpB)+0.5×?(1/fpC)}/?(1/fp)<1. Reduction-side positive lens elements disposed closer to the reduction side than the negative lens element whose effective diameter is smallest satisfy {9.0×?(1/fpA)+0.3×?(1/fpB)+2.0×?(1/fpC)}/?(1/fp)<1.

Abstract: A method for controlling movements of an optical zoom device, the method includes the steps of: setting a timer to zero, and setting a time limit; checking whether the wide-angle button or the telephoto button is pressed; starting the timer and moving the optical zoom device to a point between the current position and the next position in a direction corresponding to the pressed wide-angle button or the pressed telephoto button if the wide-angle button or the telephoto button is pressed; checking the timer to determine whether the time on the timer is less than the time limit; checking whether the pressed button is released if the time on the timer is less than the time limit; confirming a position which is nearest to the optical zoom device along the direction of current movement if the pressed button is released; and moving the optical zoom device to the confirmed position.

Abstract: An imaging lens assembly (30) for a camera assembly (20) of an imaging-based bar code reader (10) for focusing an image (100?) of a target object (100) within a field of view (FV) of the camera assembly (20) onto a sensor array (28) of the camera assembly (20). The imaging lens assembly includes a front aperture stop (31) facing the field of view (FV), the aperture stop (31) including an aperture (31a) through which light from the field of view (FV) passes. The imaging lens assembly (30) further including a three lens system (36) disposed rearward of the front aperture stop (31) and a meniscus lens (35) disposed rearward of the three lens system (36). The three lens system (36) and the meniscus lens (35) receiving light passing through the aperture (31a) and focusing the light onto the sensor array (28).

Abstract: An imaging lens comprises, in order from an object side: a first lens having a positive refractive power and a meniscus shape and having a convex surface directed to the object side; a second lens having a negative refractive power in the vicinity of an optical axis of the imaging lens; and a third lens having a positive refractive power in the vicinity of the optical axis, wherein at least one surface of each of the second lens and the third lens is an aspheric surface; and the imaging lens satisfies the following conditional expression expressions: 0.7<|f1/f|<0.8 ??(1) 0.3<|f2/f|<0.8 ??(2) 75<?d1<96 ??(3) TL/2Y<0.9 ??(4) where f: focal length of the imaging lens; f1: focal length of the first lens; f2: focal length of the second lens; ?d1: Abbe number of the first lens for the d-line; TL: length between the object-side surface of the first lens to an image forming position of the imaging lens; and Y: maximum image height.

Abstract: A two-piece type optical imaging lens that includes a first lens element with positive refractive power, a second lens element with positive refractive power, an IR cut-off filter and an image sensor arranged along an optical axis in order from an object side. The first lens element and the second lens element are both meniscus aspherical molded glass lens while a convex surface of the first lens element is on the object side and a convex surface of the second lens is on the image side. The two-piece type optical imaging lens satisfies following conditions: 0.4f?d<0.9f, 0.

Abstract: In an imaging lens, one compound lens and two single lenses are arranged in a lens barrel. On the light output side of the lens barrel, a filter is arranged with a distance from lens barrel. With a further distance from the filter, an imaging element is arranged. In the compound lens, a resin lens is bonded to a base member lens, having an output surface center of the resin lens displaced by a prescribed amount relative to an output surface center of the base member lens, so that a transmission decentration amount attributed to the base member lens, not including the resin lens, and the single lenses is cancelled by a transmission decentration amount by the resin lens when taken as a whole lens system. Thus, the imaging lens capable of suppressing reduction in resolving power due to transmission decentration of the lenses is obtained.

Abstract: The present microlens for packaging and printing includes a package including a body; and a microlens window located on the body to display at least one graphical image in a first portion of the microlens window and the contents of the package through a second portion of the microlens window.

Abstract: A high-performance lens system including lens elements of small diameters for projecting on to a screen or the like in an enlarged fashion images from light valves such as mainly DMDs (Digital Micromirror Devices) for forming images by changing reflecting directions of light is provided. A lens system includes, sequentially in that order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole, and depending upon applications, a third lens group made up of a single positive lens element is provided in the vicinity of a light valve such as a DMD on a contracting side of the second lens group.

Abstract: An imaging lens is provided and includes: in order from an object side of the imaging lens, a first lens group having a positive power as a whole; a second lens group including a lens in the most object side thereof, the lens having a concave surface on the object side thereof; a third lens group including a cemented lens of a lens having a positive power and a lens having a negative power; and a fourth lens group having a negative power as a whole.

Abstract: In a photographing lens unit, an aperture diaphragm, a first lens having positive refractive power, a second lens having negative refractive power, a third lens of a positive meniscus lens with a concave surface on the object side, an ND filter, a fourth lens of a negative meniscus lens with a convex surface on the object side, an IR cut filter, and an imaging element are disposed in order from the object side to the imaging element side. In the third lens, a surface shape on the object side changes from concave to convex as it is away from an optical axis, and a surface shape on the image side changes from convex to concave as it is away from the optical axis. In the fourth lens, a surface shape on the object side changes from convex to concave as it is away from the optical axis.

Abstract: An imaging lens includes, in order from an object side, a first lens G1, a second lens G2, a third lens G3, an aperture stop St and a fourth lens G4. The first lens is a negative lens having a meniscus shape with a convex surface directed to the object side. The second lens is a negative lens. The third lens is a positive lens having a convex surface directed to the object side. The fourth lens is a biconvex lens. The following conditional expression is satisfied: 1.5<f4/fa<2.7 ??(1) where fa denotes a focal length of the whole lens system, and f4 denotes a focal length of the fourth lens.

Abstract: The present invention relates to an optical sensor for the monitoring of combustion processes in a combustion chamber wherein the optical sensor at least comprises a lens system facing the combustion chamber, a waveguide and a sheath surrounding the lens system and one end of the waveguide characterized in that the lens system consists of at least one essentially plano-concave lens and a double concave lens wherein the planar surface of the plano-concave lens is exposed to the combustion chamber. The invention also relates to a method for the manufacture of said sensor.

Abstract: An exemplary lens module includes a number of optical components, a barrel receiving the optical components therein, an image sensor and a holder engaged with the barrel. The holder receives the image sensor therein. The holder has an electromagnetic shielding coating formed thereon. The electromagnetic shielding coating is comprised of a polymeric matrix and a number of carbon nanotubes dispersed in the polymeric matrix and is configured for blocking electromagnetic interference from outside the holder. The lens module can block electromagnetic interference.

Abstract: An optical module having a substrate which includes a light-emitting device mounting area provided on its first principal surface, a lens mounting groove with a cross section of V shape, and a support groove formed orthogonal to the lens mounting groove, and an inclined surface to allow a lens element to slide therealong. The support groove includes a bottom surface, a first side surface toward the light-emitting device mounting area, a second side surface opposed to the first side surface, and a first and a second portion defined by the lens mounting groove. The inclined surface is provided on at least one of the side surfaces. Thus, light would not be reflected by the optical module to be returned to a light source.

Abstract: A lens barrel capable of forming high-accuracy barrel body and simply adjusting a tilt and a position in an optical axis direction without using dedicated portions is provided. The lens barrel includes a front barrel and a rear barrel. An inner diameter of a portion, containing a focus lens of the front barrel, is 1.15 times or more as large as an inner diameter of a portion containing a zoom lens of the rear barrel. The rear barrel and the front barrel are coupled by a coupling screw. A convex portion has an adjustment face for adjusting a distance between the focus lens and the zoom lens and is formed on a coupling face of the front barrel. A convex portion includes a reference face serving as a reception portion and is formed on the rear barrel.

Abstract: A camera module of the present invention includes a plurality of projections 61b on a bottom base of a driving section 61 of an AF/Zoom module. The projections 61b are radially extended from an aperture 63 formed on an optical path. By this, adhesive can be spread over the projections 61b when bonding a lens holder and the AF/Zoom module together. Furthermore, even if the adhesive is excessively applied, excessive adhesive can be retained between the projections 61b. As a result, it is possible to realize a solid-state imaging device which makes it possible to improve adhesive strength between the lens holder and the AF/Zoom module and easily bond the lens holder and the AF/Zoom module.

Abstract: An HMD device has an imaging optic for the right eye and an imaging optic for the left eye. Each imaging optic so images an image, which is generated in the object plane, that the image can be observed by a user in an image plane and each of the imaging optics includes an optical element (23) and a deflecting element (25) mounted downstream of the optical element (23). An image transducer (24) and the optical element (23), which follows the image transducer (24), are held by a linearly guided receptacle frame (15) moveable via a drive unit. A linear movement in the direction of an optical axis takes place. Adjusting wheels (4, 5) are mounted on respective sides of the image window for the right and left eyes. Each of the adjusting wheels (4, 5) is coupled mechanically to a corresponding cam curve. Each cam curve translates a rotational movement of the adjusting wheel (4, 5) into an output end linear movement of the receptacle frame (15).

Abstract: In accordance with one embodiment of the present invention, a positioning device comprises a microscope assembly and a lens positioning assembly. The lens positioning assembly comprises a lens support subassembly and a bi-directional positioning guide. The lens support subassembly comprises a translating rod, while the positioning guide comprises a coiled spring. The coiled spring is canted relative to a longitudinal axis of the rod. The inner periphery of the coiled spring engages in a spring loaded state an outer periphery of the rod such that the coiled spring provides a frictional force about the outer periphery of the rod. This frictional force provided by the coiled spring about the outer periphery of the rod is sufficient to hold the rod within the inner periphery, but permit infinitely variable bi-directional movement of the rod through the inner periphery under an applied force. Additional embodiments are disclosed and claimed.

Abstract: A camera module (200) includes a lens barrel (202), at least one lens (204), a holder (206), and a base (210). The at least one lens is received in the lens barrel. The holder has a first end (212) and a second end (214). The holder further has a cavity (216) defined through the first end and the second end thereof. The first end holds the lens barrel. The second end is provided with at least two supporting protrusions (222) extending therefrom along a direction away from the first end of the holder. The base fixedly contacts with the at least two supporting protrusions. A method for assembling a camera module is also provided.

Abstract: A light conducting unit is disposed between a light source and a region which is to be illuminated. In addition, a light conducting unit includes a polygonal prism made from a first medium with a first coefficient of refraction, a first light conducting unit which directs light to be incident upon a first surface of the polygonal prism, and a second light conducting unit upon which light emitted from a second surface of the polygonal prism is incident, wherein the polygonal prism includes a reflective device which reflects light which is incident into the polygonal prism from the first surface towards the second surface, and a second medium with a second coefficient of refraction which is less than the first coefficient of refraction is provided at the first surface and the second surface.

Abstract: A driving support method and apparatus for displaying, on a medial side of a pillar of the vehicle, an image of an area which is hidden as a blind spot in a rear-view mirror mounted on or in a vehicle, when looking in the mirror from the driver's position and which is created by the pillar. The apparatus detects a head position of a driver, detects the angle of the rear-view mirror, calculates the area which is hidden as the blind spot on the basis of the detected driver's head position and the detected angle of the rear-view mirror, and projects an image of the area corresponding to the blind spot onto the pillar, the projected image being formed from image data which is obtained from a blind spot camera mounted on the vehicle.

Abstract: It is made possible to provide a deformable mirror apparatus which is deformable to a complicated shape (high-order shape). A deformable mirror apparatus includes: a substrate; a plurality of electrodes provided on the substrate; a spacer fixed above the substrate, having a first opening passing through from a first face of the spacer facing to the substrate to a second face of the spacer facing opposite from the first face, surrounding the electrodes, and having a step on the second face; a drive part including a membrane part disposed so as to cover the step of the spacer and so as to be opposed to the electrodes, a casing part having an opening at a bottom face of which the membrane part is exposed and supporting the membrane part, and a reflection film provided on the membrane part; and a voltage generator configured to generate predetermined voltage patterns on the electrodes, respectively.

Abstract: The invention concerns an external mirror arrangement comprising a front mirror of the Group of the Directive 2005/27/EG for the visual transmission of a first field of view and for the visual transmission of a second field of view contains a safety mirror. In accord with the invention, the front mirror and the safety mirror are integrated in one mirror head.

Abstract: A mirror pane comprising a substrate of plastic having a front side and a rear side, each having a metal coating, and a surface heating apparatus with at least one resistance heating strip and electric connection contacts, wherein the metal coating placed on the front side of the substrate serves as a reflective mirror surface, and the at least one resistance heating strip possessing the electrical connection contacts is located within recesses in the rear side of the recesses reproducing a negative image of the at least one resistance heating strip and being furnished with connection contacts.

Abstract: An optical device includes a deflectable optical functional structure for interacting with electromagnetic radiation incident thereon, and a protective structure which is associated to the optical functional structure and at least partly transparent for the electromagnetic radiation. The optical functional structure is arranged in a manner tilted relative to the protective structure so that, in a non-deflected position of the optical functional structure, a main beam path of the electromagnetic radiation which interacts with the optical functional structure through the protective structure has an angle relative to a sub-beam path of the electromagnetic radiation reflected at the protective structure.

Abstract: A trailer rearview mirror assembly includes a mirror base, a first clipping member and a second clipping member. The mirror base is provided with an elongated support arm. The first clipping member is affixed on the support arm by a first fastener. The second clipping member is coupled to the first clipping member, and provided with a clipping cavity which allows the gripping by a second fastener. Accordingly, the mirror base is therefore handy and stable to affix to the rearview mirror assembly.

Abstract: The present invention provides a method of magnetic transfer comprising: an initial magnetization step of performing an initial magnetization by applying a DC magnetic field perpendicular to a disk shaped perpendicular magnetic recording medium which is formed by laminating a soft magnetic layer and a magnetic layer on a substrate; an initial magnetization cleaning step of applying an in-plane magnetic field having an intensity larger than 100 [Oe] and less than an intensity of Hn, to the perpendicular magnetic recording medium after passed through the initial magnetization step in radial direction which directed from a center to an outer of the perpendicular magnetic recording medium. After or in a time of the magnetic transfer, a magnetic cleaning may be performed by applying an in-plane magnetic field having the same intensity as the initial magnetization cleaning step in radial direction instead of the initial magnetization cleaning or in combination.

Abstract: Watermarks for patterned magnetic media. The watermarks are used to demonstrate the unauthorized replication of a patterned magnetic media. The watermarks include a dibit, a pattern in an open region, shifting of data, shifting of a sync mark and large length scale perturbations. Also described are methods to determine if a watermark appears on a patterned media.

Abstract: Certifying a media while servowriting the media by formatting a full compliment of servo data in storage tracks of the media in a minimum number of passes per storage track while simultaneously performing a 100% media certification of the storage tracks during the minimum number of passes per storage track.

Abstract: According to one embodiment, in a disk drive having a disk medium that has a plurality of sectors, in each of which servo data containing a servo-burst patterns is recorded, a CPU calculates the reliability value of a sector to be evaluated, from a ratio of the sum of the servo-burst values acquired from the sector, to a value obtained by performing low-pass filtering operation on the sum acquired at the time of detection or acquired for the immediately preceding sample. The CPU then determines whether the sector is a defective sector having defective servo-burst patterns, on the basis of the reliability value thus calculated.

Abstract: According to one embodiment, a disk recorder management apparatus includes: a connection part to which a disk recorder is connected; an initial connection judging unit judging whether or not the disk recorder is connected to the connection part for the first time; and a recording control unit making the disk recorder record registration information indicating a correspondence between the disk recorder management apparatus and the disk recorder when it is judged by the initial connection judging unit that the disk recorder is connected for the first time.

Abstract: The present invention relates to a method of examining an aperture diameter of a disk substrate having a circular aperture in the central portion thereof, the method including: attempting to pass a standard sphere for the aperture diameter through the aperture; and inspecting the aperture diameter of the disk substrate, based on whether the sphere passes through the aperture or not. Furthermore, the present invention relates to an examination apparatus thereof.

Abstract: An apparatus and method for measuring the physical quantities of a data center during operation and method for servicing large-scale computing systems is disclosed. The apparatus includes a cart that supports a plurality of sensors. The cart is moveable within the data center. The sensors capture temperature or other physical parameters within the room. The sensor readings, along with position and orientation information pertaining to the cart are transmitted to a computer system where the data is analyzed to select the optimum temperature or other system environmental parameters for the data center.

Abstract: Certifying a storage media while servowriting the media by formatting a full compliment of servo data in storage tracks of the media in a minimum number of passes per storage track while simultaneously performing a 100% media certification of the storage tracks during the minimum number of passes per storage track.

Abstract: The thermally assisted magnetic head comprises a medium-opposing surface; a magnetic recording device whose distance from a main magnetic pole to a medium is set longer than a distance from the medium-opposing surface to the medium; a first core for receiving light; and a second core positioned between a first light exit surface of the first core and the medium-opposing surface, having a second light exit surface on the medium side; while a distance between positions where an optical intensity distribution center within the first light exit surface and a center of the main magnetic pole are orthographically projected onto a reference plane including the second light exit surface is greater than a distance between an optical intensity distribution center within the second light exit surface and the position where the center of the leading end of the main magnetic pole is orthographically projected onto the reference plane.