Abstract: In a document lighting device, each of the plurality of the light emitting elements arrayed in a light source unit is arranged in a vicinity of a focal point on a cross section in a sub-scanning direction of a long-sized lens, and a convergent point is placed at a location departing a predetermined distance in the main scanning direction from a location on the surface to be illuminated included in the sub-scanning cross section.

Abstract: A method for printing a pattern from a hologram mask into a photosensitive layer on a substrate, which method includes arranging the hologram mask on a coupling element, arranging the substrate so that it is substantially parallel with the hologram mask and separated from it by an amount substantially corresponding to the focal distance of the hologram mask, reconstructing the pattern recorded in the hologram mask by scanning an exposure beam of substantially collimated across the hologram mask while continuously measuring the local separation between the hologram mask and substrate in at least two locations where the pattern is being reconstructed by scanning at least two focus beams across the hologram mask, and continuously adjusting the separation and the angle of tilt between the hologram mask and substrate in order that the pattern reconstructed from the hologram mask is accurately focussed onto the photosensitive layer on the substrate.

Abstract: A first wall is installed on a bottom portion of a housing along an outer peripheral thereof orthogonally to the bottom portion. A second wall is installed opposite to the first wall at a predetermined interval. Between the first wall and the second wall, a first rib parallel with the bottom portion for connecting the first wall and second wall is installed. Further, under the first rib, second ribs orthogonal to the bottom portion for connecting the first wall, second wall, and first rib are installed at fixed intervals. Furthermore, above the first rib, third ribs orthogonal to the bottom portion having the same height as that of the first wall and second wall for connecting the first wall and second wall are arranged so as to be shifted in position from the second ribs.

Abstract: An optical channel monitor is provided that sequentially or selectively filters an optical channel(s) 11 of light from a (WDM) optical input signal 12 and senses predetermined parameters of the each filtered optical signal (e.g., channel power, channel presence, signal-noise-ratio). The OCM 10 is a free-space optical device that includes a collimator assembly 15, a diffraction grating 20 and a mirror 22. A launch pigtail emits into free space the input signal through the collimator assembly 15 and onto the diffraction grating 20, which separates spatially each of the optical channels 11 of the collimated light, and reflects the separated channels of light onto the mirror 22. A ?/4 plate 26 is disposed between the mirror 22 and the diffraction grating 20. The mirror reflects the separated light back through the ?/4 plate 26 to the diffraction grating 20, which reflects the channels of light back through the collimating lens 18.

Abstract: An image acquisition module in a transmission device for a scanner is installed in a base of the scanner, a rotating wheel and a first roller are pivotally connected onto two inner sides of the base, and a driving roller is installed below the first roller. A conveyor is respectively put around the rotating wheel, the first roller and the driving roller, and a second roller is pivotally connected onto a place between the rotating and the driving roller and used for withstanding the conveyor between the rotating wheel and the driving roller to allow the conveyor between the rotating wheel and the second roller to be parallel to the conveyor between the rotating wheel and the first roller, and the conveyor is driven by the driving roller to drive the image acquisition module to move.

Abstract: In an optical scanning device 1, a housing 3 has a space 3a in the inside thereof. A floating rotational plate 2 is housed in the space 3a, and is caused to float and to rotate by a magnetic force. The floating rotational plate 2 has an optical deflection layer 6 thereon. A diffraction grating 71 is formed on the optical deflection layer 6 on and around the center axis Z of the floating rotational plate 2. When a beam of light falls incident on the diffraction grating 71 in a direction normal to the surface of the optical deflection layer 6, the diffraction grating 71 diffracts the light in a radius direction of the circular-shaped floating rotational plate 2. The light is transmitted through optical waveguides 20 and 51 to be emitted outside from the housing 3. By rotating the small-sized floating rotational plate 2 at a high speed inside the housing 3, it is possible to scan the light at a high speed and with a high resolution.

Abstract: Electromagnetic waves in wide frequency ranges up to photonics have been used for applications to time-domain imaging (TDI). Realistic time domain imaging requires a rapid optical delay line on the order of 100 ps with sampling rate at least 100 Hz. Present available optical time delay systems suffer either from low sampling rate or low time delay length, deviating from ideal requirements. The purpose of this invention is to introduce a miniature and rapid scanning optical delay line based on micro-opto-electro-mechanical system (MOEMS) technology to improve the data acquisition in time domain imaging, capable of sampling rate beyond 100 Hz and time delays beyond the 100 ps.

Abstract: A holographic display comprises a light source and an Electrically Addressable Spatial Light Modulator (EASLM) 1 in the path of the light source. A light guide is arranged to guide light from the EASLM to each of a set of tiled regions of a OASLM in turn. The Optically Addressable Spatial Light Modulator (OASLM) 8 has a monostable light modulation property which is changed from a first state to a second state by incident light.

Abstract: An optical scanning unit with a rotatable hologram disc, including a light source, a rotatable hologram disc provided with a plurality of holograms, the holograms being formed concentrically along a radial direction to diffract a beam emitted from the light source by multiple steps, a reflecting member that reflects the beam emitted from the light source and diffracted by one of the holograms into another hologram, and a fixed hologram correcting the diffracted beam incident through the rotatable hologram disc to focus it on a scanning object. In the optical scanning unit, the light passes through the plurality of holograms formed along a radial direction of the rotatable hologram disc so that a scan width can be extended without reducing a scan speed of the optical scanning unit.

Abstract: A scanning optical system includes a first optical system for shaping a light beam emitted from a light source and forming the light beam into a linear image elongated in the same direction as a main scanning direction, a light deflector which has a deflection surface near an imaging position of the first optical system and deflects/scans the incident light beam in the main scanning direction, a second optical system for forming the light beam deflected by the light deflector into an image on a scanned surface in the main scanning direction, and a third optical system for forming the light beam deflected by the light deflector into an image on the scanned surface in a sub-scanning direction and setting the deflection surface of the light deflector and the scanned surface optically conjugate with each other. The light beam guided by the first optical system is made to strike said light deflector at a predetermined angle with respect to a plane perpendicular to a rotation axis of the light deflector.

Abstract: An image displaying configuration is arranged so that objects and scenes at the distance of the fixation point are images in focus, and objects and scenes at distances other than the distance of the fixation point are subjected to out-of-focus processing according to the distance from the fixation point, based on the fixation point position information for both right and left eyes, and based on the distance information of the shown image, whereby an image is shown. This configuration allows three-dimensional images with a sensation closer to real space to be shown, thus providing for an image processing apparatus and image processing method capable of three-dimensional images with increased sensations of reality.

Abstract: An optical crossbar switch system includes: a mask comprising multiple patterns, wherein at least one of the multiple patterns is a diffractive pattern; and a spatial light modulator positioned to receive at least one optical input beam and selectively couple at least a portion of each of the at least one input beam to one of the patterns of the mask, each coupled portion defining an intermediate beam, wherein each pattern, when selected by the spatial light modulator, is configured to redirect the intermediate beam to one of N targets, where N is an integer greater than two. Further, a method for selectively coupling at least one input beam to one of multiple output channels includes: selectively coupling at least a portion of each of the at least one input beam to one of multiple patterns on a mask; and diffracting at least one of the coupled portions from the mask to one of the output channels.

Abstract: An optical scanning device is provided, which is compact-sized and lightweight, and, which consumes less power. A movable member of the device is supported on a fixed member via a swing axis provided on the fixed member. On an upper surface and along an axial line of swing of the movable member, there are disposed a light emitting unit and a light receiving unit. When an AC current flows through a coil provided in the movable member, electromagnetic force acting on the coil when traversing a magnetic circuit comprising a yoke and a permanent magnet both provided on the fixed member urges the movable portion to swing around its swing axis at a predetermined cycle. A laser bean L from the light emitting unit scans a bar code and a reflected light L′ from the bar cord is received by the light receiving unit thereby reading information of the bar code.

Abstract: A hologram scanner is constructed with a driving source for providing a rotational force, a deflection disk installed at the rotation shaft of the driving source for forming a scanning line, the deflection disk having a plurality of sectors where a hologram pattern for diffracting and deflecting incident light is formed, a TE polarized light emitting device, arranged to face one side of the deflection disk, for emitting TE polarized light so that major axis of an elliptical spot formed at a predetermined position on the deflection disk by the incident light is perpendicular to the radius vector of the deflection disk passing through the spot having an elliptical cross-section and a TE polarization mode, and an optical path altering device for altering the proceeding path of incident light, so that a scanning line formed by the rotation of the deflection disk proceeds to a photoreceptor medium.

Abstract: Disclosed is a multi-beam optical system that includes a laser source, a diffractive beam dividing element that divides the light beam emitted from the laser source into a plurality of light beams, a propagation optical system through which the divided light beams propagate, a polygon mirror and a scan lens. The propagation optical system includes a curved surface mirror that is arranged such that center axes of the reflected light beams are spatially separated from center axes of the incident light beams at a predetermined separation angle. The diffractive beam-dividing element Is arranged such that the center axis of the incident light beam is inclined with respect to the normal to a diffraction grating surface thereof so as to compensate bending of a beam spot line, along which the beam spots align, depending on the separation angle of the curved surface mirror.

Abstract: In an optical scanning device 1, a housing 3 has a space 3a in the inside thereof. A floating rotational plate 2 is housed in the space 3a, and is caused to float and to rotate by a magnetic force. The floating rotational plate 2 has an optical deflection layer 6 thereon. A diffraction grating 71 is formed on the optical deflection layer 6 on and around the center axis Z of the floating rotational plate 2. When a beam of light falls incident on the diffraction grating 71 in a direction normal to the surface of the optical deflection layer 6, the diffraction grating 71 diffracts the light in a radius direction of the circular-shaped floating rotational plate 2. The light is transmitted through optical waveguides 20 and 51 to be emitted outside from the housing 3. By rotating the small-sized floating rotational plate 2 at a high speed inside the housing 3, it is possible to scan the light at a high speed and with a high resolution.

Abstract: An apparatus for generating a pattern on a photomask includes a beam generator generating a row of spaced apart optical beams, a blocking element downstream from the beam generator in a path of at least one of the optical beams, and a refracting element downstream from the blocking element for aligning optical beams closer together and while leaving an enlarged beam spacing downstream from the at least one blocked optical beam. The apparatus further includes a modulator downstream from the refracting element for defining the pattern to be generated on the photomask. The apparatus generates the row of spaced apart optical beams with an enlarged beam spacing between the two central beams without using high precision mirrors that are expensive to produce and requires precise alignment with respect to one another.

Abstract: An optical scanning unit with a rotatable hologram disc, including a light source, a rotatable hologram disc provided with a plurality of holograms, the holograms being formed concentrically along a radial direction to diffract a beam emitted from the light source by multiple steps, a reflecting member that reflects the beam emitted from the light source and diffracted by one of the holograms into another hologram, and a fixed hologram correcting the diffracted beam incident through the rotatable hologram disc to focus it on a scanning object. In the optical scanning unit, the light passes through the plurality of holograms formed along a radial direction of the rotatable hologram disc so that a scan width can be extended without reducing a scan speed of the optical scanning unit.

Abstract: An apparatus and process for ablating an array matrix of high-density vias in a flexible and rigid desired object. The apparatus contains a mirror based x, y scanning repeat positioning and/or a single axis scanner positioning system that directs a single point of a coherent light radiation beam at desired individual mask segments. These mask segments are formed into a planar mask array. A flat field collimating lens system is positioned between the mirror scanning system and the mask arrays to correct the angular beam output of the repeat positioning mirror and redirects the beam so that it strikes a specific rear surface segment(s) of in the mask array. The flat field collimating lens provides a beam that either illuminates the mask perpendicular to its surface or at preselected optimized illumination angles.

Abstract: A scanner includes a single scanning element such as a holographic disc or a polygon mirror and an illumination system that provides a plurality of input beams that are directed to different areas on the scanning element. In one embodiment, a light source provides a single beam that is alternately directed to a first area and a second area. While an input beam is incident on the first area, a first scan line forms. While an input beam is incident on the second area, a second scan line forms. Duty-cycle and energy efficiency of this embodiment are high because the beam from the source is switched from one area to the other during dead time when a scan beam would not otherwise have been directed to the desired scan aperture. Separate scan lines are automatically synchronized since they originate from the same source. Thus, alignment of multiple scan lines to form an extended scan line is simplified.

Abstract: The present invention relates to an optical scanner (20) comprising a radiation source (24) for generating a radiation beam, and means (22), (26) for giving the radiation beam a scanning movement in a first direction through an angular range &Dgr;&thgr;1 and in a second direction through an angular range &Dgr;&thgr;2. The radiation source (24) is, for example a diode laser and is tunable in wavelength, and the means comprise a rotating reflecting element and a grating.

Abstract: A pattern reading apparatus includes an objective lens positioned opposite an object surface, the object surface being a reflection surface having a pattern formed thereon as an object to be read. A minute-area light source is positioned to be conjugate with a center of curvature of the object surface through the objective lens, for illuminating the object surface through the objective lens. An imaging lens is positioned farther from the object surface than the light source, with the optical axis of the imaging lens being coincident with the objective lens. An imaging element reads the image of the pattern which is reflected at the object surface and formed through the objective lens and the imaging lens.

Abstract: A laser scanning unit (LSU) in a structure capable of radiating heat generated by a light source. The LSU includes at least one light source, a driving source for providing rotational force, and a deflection disk installed on a rotary shaft of the driving source, for diffracting and deflecting light incident from the light sources. The deflection disk has at least one radiating portion which is depressed in and/or protrudes from the surface of the deflection disk facing the light source and induces air flow by contact with air, such that the heat generated by the light sources is radiated by the air flow induced due to the radiating portion.

Abstract: A multi-laser scanning unit (LSU) in which scanning lines incident parallel onto a photoreceptor have the same scanning direction. The multi-laser scanning unit includes: a driving source for providing a rotatory force; a deflection disk installed around a rotary shaft of the driving source having a plurality of sectors each with a hologram pattern for diffracting and deflecting incident light, for scanning light through rotation; a plurality of light sources installed facing one surface of the deflection disk for irradiating a plurality of light lines onto predetermined points of the deflection disk; and a light path changing portion for changing traveling paths of the plurality of scanning lines formed by the rotation of the deflection disk, wherein the plurality of light sources are arranged such that two incident points which are the farthest from each other among the plurality of incident points formed on the deflection disk form 180° with the center point of the deflection disk.

Abstract: A laser scanning apparatus including an optical source installed on a main frame, a scan disk which is rotatably installed on the main frame and has diffraction patterns formed thereon for deflecting a beam emitted from the optical source in a predetermined direction to achieve a normal light path, and a means for shielding an abnormal beam that is emitted from the optical source and diffracted or reflected off the normal light path by the scan disk.

Abstract: A multi-laser scanning unit (LSU) in which scanning lines incident parallel onto a photoreceptor have the same scanning direction.

Abstract: A light-beam scanning apparatus includes at least two holograms with an optical path length difference .DELTA..PHI. along a scanning beam light flux. The path length is measured from a light source to a scanning surface in the first hologram, and is represented by .DELTA..PHI.<C(.lambda..sup.2 /D.lambda.) where C is a constant less than 0.5. The path length is related per the above equation to a wavelength, .lambda., at the center of the light source, and a wavelength displacement .DELTA..lambda. measured from the wavelength .lambda. at the center of the light source.

Abstract: Disclosed is a scanning optical system including a light source that emits a light beam, a deflector that deflects a light beam emitted from the light source to scan in a predetermined direction, an scanning lens system that allows the light beam deflected by the deflector to pass through and converges the light beam on a surface to be scanned, and a diffracting element having a diffracting surface that functions to correct a chromatic aberration of the scanning lens. The diffracting element is arranged between the deflector and the surface to be scanned.

Abstract: A holographic spectroscope for a two-motor reflection system for generating scanning patterns in which a light beam is first reflected by a first reflector connected to a first motor electrically connected to a first control circuit. A second reflector for reflecting the light beam reflected by the first reflector is connected to a second motor electrically connected to a second control circuit and to form scanning patterns. A holographic spectroscope for diffracting the scanning patterns is mounted in the optical path of the light beam from the second reflector. Therefore, the scanning patterns can be improved to be more variable.

Abstract: An optical assembly utilizing a novel optical element. The assembly includes a tunable source of input radiation; an optical element that can receive at least a portion of the input radiation and comprises a manifold having at least two independent surfaces, in which at least a portion of each independent surface is selected from the group consisting of a reflective structure and a diffractive structure, and the independent surfaces are geometrically configured so that a portion of incident radiation to the manifold is diffracted at least twice in an angular sense that can increase a tuning sensitivity of an angular deviation of the incident radiation exiting the manifold; and, a scanner means which can accept and redirect a portion of the radiation output by the optical element for producing an illumination pattern.

Abstract: A beam scanning apparatus includes an optical source, a beam deflector having a deflection disk which is comprised of a plurality of sectors patterned to diffract a beam emitted from the optical source and has a reflective layer for reflecting an incident beam formed on the bottom surface of the beam deflector, and a driving source for rotating the deflection disk. A beam corrector is provided for correcting the beam deflected by the beam deflector.

Abstract: A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems such as optical lenses or a mirror having curvature, and capable of compensating for disadvantages including scanning beam thickening and variation, failure of a rotatable hologram to rotate at a constant velocity, displacement of a scanning beam position in the scanning direction and the cross scanning direction due to a mode hop of a wavelength of a semiconductor laser, and deviation of a base of rotatable hologram from a parallel state. These disadvantages are detrimental to efforts for increasing the resolution of a hologram scanner and lowering the cost thereof. The light beam scanning apparatus includes at least two holograms, one rotatable and one fixed, wherein the fixed hologram plate has a phase distribution .PHI..sub.H represented as a difference obtained when subtracting a reference wave phase .PHI..sub.0 from an object wave phase .PHI..sub.

Abstract: A holographic laser scanning system for producing a highly defined 3-D scanning volume for omni-directional laser scanning of bar code symbols therein having a minimum element width on the order of about 0.017 inches or less. The holographic laser scanning system comprise a housing, a plurality of laser sources, a holographic scanning disc and a plurality of photodetectors. The plurality of lasr sources are disposed within the housing, for producing a plurality of laser beams. The holographic scanning disc is disposed within the housing, and has a plurality of holographic optical elements for scanning the laser beams and producing a plurality of laser scanning planes for scanning a code symbol. Each laser scanning plane has predefined beam characteristics and is spatially confined within a highly-defined 3-D scanning volume having at least three focal zones, a depth of field of at least 10 inches, and a scanning volume of at least 1,440 cubic inches.

Abstract: A multi-beam scanning apparatus includes at least two optical sources, a beam deflector having a deflection disc with a plurality of sectors for diffracting and transmitting incident beams, and a driving source for rotating the deflection disc, for deflecting and projecting beams emitted from the optical sources. A beam corrector installed along a light path, for correcting the beams deflected by the beam deflector.

Abstract: A holographic laser scanning system comprising: a housing of compact construction; a plurality of laser beam sources; a holographic scanning disc supporting a plurality of holographic optical elements having fringe structure of variable spatial frequency; a plurality of laser beam folding mirrors disposed about the holographic scanning disc; a plurality of light focusing surfaces disposed below the holographic scanning disc; and a plurality of photodetectors disposed at the focal points of the light focusing surfaces. During laser beam scanning operations, each laser beam is transmitted through the outer edge portion of each holographic optical element at an angle of incidence substantially greater than twenty-three degrees relative to a normal vector drawn thereto, preferably forty-three degrees.

Abstract: A method of manufacturing a fixed hologram plate of a light-beam scanning apparatus for diffracting a light incident from a light source portion by a rotatable hologram, scanning by the diffracted light through the rotation of the rotatable hologram, diffracting the resulting light by the fixed hologram plate, and for conducting a light-beam scanning on a scanning surface. The method includes the steps of preparing an interference fringe distribution of the fixed hologram plate by two waves: a first wave having a spherical aberration, a transverse aberration of the first wave is in the Y direction, the transverse wave including an astigmatism and a coma; and a second wave having a spherical aberration and astigmatism, and having a wavelength different from a wavelength of a reconstructing wave that is selected to minimize distortion, wherein a transverse aberration of the second wave is in the X direction.

Abstract: A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems, and capable of compensating for disadvantages.

Abstract: A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems such as optical lenses or a mirror having curvature, and capable of compensating for disadvantages including scanning beam thickening and variation, failure of a rotatable hologram to rotate at a constant velocity, displacement of a scanning beam position in the scanning direction and the cross scanning direction due to a mode hop of a wavelength of a semiconductor laser, and deviation of a base of rotatable hologram from a parallel state. These disadvantages are detrimental to efforts for increasing the resolution of a hologram scanner and lowering the cost thereof. The light beam scanning apparatus includes at least two holograms with an optical path length difference .DELTA..PHI. along a scanning beam light flux. The path length is measured from a light source to a scanning surface in the first hologram, and is represented by .DELTA..PHI.<C(.lambda..sup.2 /D.lambda.

Abstract: A scanner head cartridge, which can be mounted exchangeably with an ink head cartridge on a carriage capable of moving the ink head cartridge of an information processing apparatus for recording on a recording medium, includes a lower case containing therein optical parts required for reading, an upper case structured to be coupled with the lower case for covering the open face of the lower case and guiding means arranged on the upper surface of the upper case for positioning when being inserted into the carriage. With the structure thus arranged, it is possible to mount the scanner head cartridge on the carriage by a simple mounting operation with a highly precise positioning simultaneously.

Abstract: An original placement table is provided, on which an original sheet is placed. An original scanning device causes a light beam to scan the original sheet placed on the original placement table. A light receiving device receives a light beam which has been reflected by the original sheet placed on the original placement table after being emitted by the original scanning device. An original edge determining device monitors light intensity of the light beam received by the light receiving device. The original edge determining device determines that the light beam currently being received by the light receiving device is the light beam reflected by an edge of the original sheet placed on the original placement table when a significant variation is detected in the light intensity either for the first time or for the last time in one scanning operation of the original scanning device.

Abstract: An optical scanning system includes a laser source, a deflector deflecting a laser beam emitted from the laser source, and at least two hologram elements located between the deflector and an image forming member.

Abstract: A portable 3D scanning system collects 2D-profile data of objects using a combination of a laser-stripe positioning device and a video camera which detects the images of the laser stripe reflected from the object. The scanning system includes a laser-stripe generator, a video camera, a scanning mirror attached to a continuously rotating motor, an encoder or a photodiode operationally coupled to the motor, and associated electronics. As the rotating, scanning mirror reflects the laser stripe and variably positions the laser stripe across the object, the encoder or the photodiode generates signals indicating the angular position of the mirror. The video images of the reflected laser stripes are stored on a storage medium, while data relating to the angular positions of the laser stripes recorded in the video images are simultaneously stored on a storage medium.

Abstract: A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems, and capable of compensating for disadvantages.

Abstract: A scanner (40) is disclosed which includes a source of coherent light (12), a radial holographic deflector (16), a F.theta. lens (62), which images a scanned spot onto an image plane (18). The F.theta. lens (62) is comprised of a decentered aspheric mirror (64) and a diffractive--refractive toroidal lens (66). The apparatus is relatively insensitive to variations in the wavelength of the source of coherent light.

Abstract: A high resolution film scanner or telecine uses a microlithographic diffuser laminate (24) arranged adjacent the film. The diffuser diffuses a collimated light beam produced from a light source and the optics of a film scanner or telecine. This type of diffuser is inexpensive, yet produces a more uniformly distributed light intensity and aids in the reduction in visibility of surface imperfections such as scratches on the scanned film.

Abstract: An improved optical system having diffractive optic elements is provided for scanning a beam. This optical system includes a laser source for emitting a laser beam along a first path. A deflector, such as a rotating polygonal mirror, intersects the first path and translates the beam into a scanning beam which moves along a second path in a scan plane. A lens system (F-.theta. lens) in the second path has first and second elements for focusing the scanning beam onto an image plane transverse to the scan plane. The first and second elements each have a cylindrical, non-toric lens. One or both of the first and second elements also provide a diffractive element, which provides not only astigmatic correction, but may further provide chromatic aberration correction of the scanning beam. This astigmatic correction is achieved without the presence of any lens having a toroidal (toric) surface. The system may further have a third element in the first path of the beam prior to the deflector.

Abstract: An optical reading apparatus includes an optical scanning unit for emitting upward a scanning light beam to be used to optically read information on an article; and a supporting mechanism for supporting the optical scanning unit so that the optical scanning unit is maintained in a space over a surface of a counter in a state where a distance between the optical scanning unit and the surface of the counter is a predetermined length.

Abstract: An optical scanning apparatus is equipped with a light source for outputting a scanning beam having a single fixed direction polarization component. A polarization control element is provided for changing the polarization direction of the scanning beam outputted from the light source. An optical element is provided for splitting the scanning beam outputted from the polarization control element into two linearly polarized beams that orthogonally cross each other. An image formation element is utilized for forming images with the two linearly polarized beams outputted from the optical element at independent locations on a scanning surface. A signal processing device is provided for controlling the light source and the polarization control element, and for switching on and off the two linearly polarized beams.

Abstract: An inclined mirror is provided in a cylindrical housing which has an open end and a closed end. An optical planar glass plate or window is mounted at the open end of the cylindrical housing. A laser beam enters the housing through the window and is reflected off the inclined mirror. The reflected beam leaves the housing through a side aperture in the housing. The cylindrical housing is rotated to scan the beam through a range of angles. Rotation of this optical system induces astigmatism in the beam due to the deformation of the inclined mirror at high rotational speed. If the window is tilted so that the entering laser beam is no longer normal to the window surface, then the window will induce a degree of astigmatism in the laser beam. The angular position of the window can be adjusted relative to the inclined mirror, thus compensating for the dynamic astigmatism due to rotation.

Abstract: An original placement table is provided, on which an original sheet is placed. An original scanning device causes a light beam to scan the original sheet placed on the original placement table. A light receiving device receives a light beam which has been reflected by the original sheet placed on the original placement table after being emitted by the original scanning device. An original edge determining device monitors light intensity of the light beam received by the light receiving device. The original edge determining device determines that the light beam currently being received by the light receiving device is the light beam reflected by an edge of the original sheet placed on the original placement table when a significant variation is detected in the light intensity either for the first time or for the last time in one scanning operation of the original scanning device.