Abstract: An image reading apparatus includes a first reading part which reads a first side of a document, a second reading part located on a document discharge path which reads a second side of the document with an image sensor, a path narrowing member positioned across from the image sensor on the document discharge path; and an adjusting unit, wherein the adjusting unit adjustably moves the path narrowing member closer to and farther away from the image sensor in order to correspondingly move the document closer to and farther away from the image sensor. The image reading apparatus is capable of increasing reading speed when a one-side reading of a document is performed as well as minimizing any damage done to data produced by the reading when a double-side reading of a document is performed.

Abstract: A printer includes an upper unit which opens and closes about a fulcrum lying at a rear position of a lower unit, and a paper path which is opened by opening the upper unit. A sensor unit is attached to the lower unit and includes a lower sensor holder and an upper sensor holder which are disposed in opposition to each other via the paper path. The paper path can be opened by pivoting the upper sensor holder relative to the lower sensor holder. When the upper unit is closed, the upper sensor holder is also closed in accordance with a closing pivoting motion of the upper unit.

Abstract: The presently described embodiments provide for halftone-aligned averaging and noise reduction in a calibration method and associated system. Halftone-aligned averaging is implemented, in one form, as a method of averaging in which the window over which an average is computed is a multiple of the halftone period. Noise reduction, in one illustrative embodiment, comprises discarding windows having an average outside of the range from the 5th to the 95th percentiles of all windows for a patch.

Abstract: Method embodiments herein print a test document using a multi-function printing device to produce a printed document. This printed document is examined in a first direction to determine a first skew of the printing device. The first skew comprises a combination of raster output scanner skew and media path skew. The printed document is also examined in a second direction to determine a second skew. However, this second skew only includes the media path skew of the printing device. Once these two skews are acquired, the method can subtract the media path skew from the first skew to calculate the raster output scanner skew of the printing device.

Abstract: A display apparatus includes a display unit, a flash ROM that is provided in a microcomputer to drive the display unit and has a given color data area preset, and a color calibration unit to calibrate color in the display unit according to color data arrangement recorded on the color data area of the flash ROM.

Abstract: An image-reading device includes an image sensor, a clock generator, a resolution setting unit, and a resolution switching unit. The image sensor has a plurality of photodetectors arranged linearly. The clock generator generates clocks having a clock speed. The resolution setting unit sets a resolution of the image sensor. The resolution switching unit switches the resolution set by the resolution setting unit when one of the plurality of photodetectors has read a border pixel between a pixel segment inside the original document and a pixel segment outside the original document while reading one line of the original document.

Abstract: An image sensor 20A contains a photodiode array portion 21, a signal processor 22, a switching instruction part 23A and a control part 24A. Each switch SWn is provided between the corresponding photodiode PDn and the common output line L, and instructed to carry out the switching operation by the switching instruction part 23A so as to be closed, whereby the charges accumulated in the junction capacitance portion of the photodiode PDn are output to the common output line L. On the basis of the instruction from the switching instruction part 23A, the N switches SW1 to SWN carry out the switching operation so that the N switches SW1 to SWN are set to the close state in the different periods and the interval at which each switch SWn is set to the close state is equal to an integral multiple of a base period. As described above, the charge accumulation time of each of the N photodiodes PD1 to PDN is set to an integral multiple of the base period.

Abstract: An image-reading device includes a plurality of image sensors, a starting signal generator and a signal timing regulator. Each image sensor reads images on a pixel basis and generating an image signal indicative of the image. The image signal is an analog signal. The starting signal generator generates starting signals at every predetermined time period. A sampling period for sampling the image signal is set within the predetermined time period. In response to the starting signal sequentially inputted to the image sensors, the image sensors read the image until the predetermined time period is expired. The signal timing regulator delays an input timing at which the starting signal is inputted to the image sensor so that the sampling periods for the plurality of image sensors are different from one another.

Abstract: An image-reading device includes a plurality of image sensor chips, a switch, an output selector and a controller. The plurality of image sensor chips is juxtaposed along a line extending in a widthwise direction of an original document carrying images thereon. Each image sensor chip includes a plurality of image sensors, reads the images on the original document, and generates image signals. The switch is configured to combine at least two image sensor chips into one virtual image sensor chip. The output selector allows the image signals from the virtual image sensor chip and remaining image sensor chip to be outputted. The controller controls the switch depending on the width of the original document, and controls, depending on the width of the original document, the output selector to allow the image signals to be outputted.

Abstract: Systems, methods and devices, including program instructions, are provided for improving halftoning techniques. One method includes receiving continuous tone (contone) image pixel data and assigning a color within the contone image pixel data to a color channel associated with a hybrid halftoner.

Abstract: An image forming apparatus includes: a creating section which creates a multiple-up image to be printed on a sheet from a plurality of document, wherein the multiple-up image having a plurality of marks corresponding to one document and a sheet number corresponding to order of outputting a sheet; and an image printing section which prints the multiple-up image on a sheet.

Abstract: A head-up display apparatus mainly includes a SH unit including switching hologram (SH) devices which constitute a combiner, a display device for supplying an image source to the SH unit, a light source controller for controlling the light source in the display device, a SH controller for controlling the SH devices, and a controller for controlling the entire apparatus including the light source controller and the SH controller.

Abstract: A light conductive controlled shape droplet display device of the invention includes a light source. A light conductive substrate receives and conducts light from the light source. A cover disposed relative to the substrate, conducts light received from the substrate out and away from the display device. Pixels in the display are defined by fluid droplets in optical communication with the substrate and the cover. Hydrophobic layers associated with the substrate and the cover control the shape of the fluid droplet in conjunction with properties of the fluid droplet. Persistent displays are possible, as are displays that require periodic refresh to maintain the display. Electrodes modulate the amount of light conducted by the fluid droplets from the substrate into the cover. In preferred embodiments, each pixel includes sub-pixels formed by different primary colored fluid droplets.

Abstract: A color image sensor has a plurality of pixels. On the pixels zero-order diffractive color filters (DCFs) (1) are arranged. Different zero-order DCFs (1), e.g., DCFs (1) transmitting red, green and blue light, respectively, are allocated to the pixels of the color image sensor. The use of DCFs (1) for color imaging devices brings better defined band-pass or notch filters than the presently used lacquers. The DCFs (1) are more stable with respect to time, temperature and any environmental aggression. The manufacture of the DCF pattern is simpler and cheaper than that of a conventional dye-filter pattern, since the different types of DCFs can be manufactured simultaneously.

Abstract: An scanning unit scanner includes a light source and a polygon mirror unit. A front-to-rear rib is disposed between the light source and the polygon mirror unit and near the polygon mirror unit. An input side opening having a slit shape is formed as a cutout in the top edge of the front-to-rear rib. When laser light from the light source passes through the input side opening, the input side opening restricts the width of the light in a main scanning direction.

Abstract: An image forming apparatus is provided to enhance a resolution of an image by controlling a process speed and a laser scanning method thereof. Such an image forming apparatus comprises a laser scanning unit having at least two laser diodes to form an electrostatic latent image on a photosensitive body with laser beams emitted from the laser diodes; an engine driving unit having at least one driving motor to drive a plurality of built-in units; and a control unit arranged to control one of the laser scanning unit and the engine driving unit to change one of a process speed of the engine driving unit and a scan speed of the laser scanning unit with a certain rate depending on a resolution selected from an external source when the laser scanning forms the electrostatic latent image on the photosensitive drum.

Abstract: An optical scanning device includes a light deflector that deflects light beams from a light source device and an optical scanning optical system that focuses the light beams deflected by the light deflector on a surface to be scanned, wherein the light beams are made incident on a deflective reflection surface of the light deflector at an angle in a sub-scanning direction with respect to a normal of the deflective reflection surface. The optical scanning optical system has at least one scanning focus lens, and at least one lens surface of the scanning focus lens is a surface, curvature in the sub-scanning direction of which changes according to an image height, and is a surface, curvature in the sub-scanning direction of which on a reference axis of the lens is zero or substantially zero, in order to effectively correct a scanning line curve and deterioration in a wavefront aberration.

Abstract: A temperature-compensated collimating lens provided of a single piece of lens, which does not have variation in its focal distance due to temperature changes, and an optical scanning apparatus using the same. The collimating lens to transform a ray of light from a light source into approximate parallel rays. The collimating lens is provided a single lens of plastic, and the single lens has a refraction surface provided on one side and a diffraction surface provided on the other side. The refraction surface and the diffraction surface have predetermined powers to prevent power of the collimating lens from changing due to change in temperature. The refraction surface and the diffraction surface have a power to satisfy the condition of, - 3 ? K d K r ? - 2.

Abstract: A method and system for determining specific pixel modulation states of a spatial light modulator (SLM) to print a desired pattern on a substrate are disclosed. The method includes selecting at least one super-pixel in an object plane of the desired pattern, the super-pixel being formed of at least two pixels. At least one edge of the desired pattern crosses a boundary within the super-pixel, the at least one edge being defined by specific slope and position parameters relative to the super-pixel. The method also includes (i) forming an interpolation table to tabulate pre-calculated pixel modulation states and (ii) determining the specific pixel modulation states for each of the pixels in accordance with the interpolation table. Disclosed also are a method and system for providing a spatial light modulator (SLM). The SLM includes a plurality of mirrors structured to form groups of super-pixels.

Abstract: An electrochromic window includes a first transparent substrate having a first electrically-conductive coating and a second transparent plastic substrate having a second electrically-conductive coating. An electrochromic medium is located between the first and second electrically-conductive coatings. At least one of the first and second electrically-conductive coatings comprises a metal layer located between first and second metal oxide layers. A plurality of first spaced facilities contact the first electrically-conductive coating and a plurality of second spaced facilities contact the second electrically-conductive coating.

Abstract: An electrochromic window includes a first transparent, e.g., plastic, substrate having a first primer over at least a portion thereof and a first electrically conductive coating over at least a portion of the first primer. A second transparent plastic substrate has a second primer over at least a portion thereof and a second electrically conductive coating over at least a portion of the second primer. The first primer has a coefficient of expansion less than the coefficient of expansion of the first plastic substrate, and the second primer has a coefficient of expansion less than the coefficient of expansion of the second plastic substrate. An electrochromic medium is located between the first and second electrically conductive coatings. At least one of the first and second electrically conductive coatings has a metal layer located between first and second metal oxide layers.

Abstract: An electrochromic switchable transparency, e.g. a window and/or a mirror includes an electrochromic switchable medium between a pair of electrode assemblies. At least one of the electrode assemblies is transparent to visible light and includes an electrode over a surface. In one nonlimiting embodiment of the invention, the electrode has two electrically conducting layers and a bridging layer between and interconnecting the two electrically conducting layers. In one nonlimiting embodiment, the bridging layer includes a high electrically resistance connecting layer to provide the electrode with a heating layer to heat the surface and/or a current conducting layer to pass current to the medium. In another nonlimiting embodiment, the bridging layer includes an electrically connecting layer to pass current to electrically enhance the first electrically conductive layer.

Abstract: Disclosed are compositions, which are stabilized against degradation and yellowing during exposure to ultraviolet light by the presence of certain nitroxyl, hydroxyl amine and hydroxyl amine salt additives, a method of stabilizing the compositions by the addition of said additives, to the use of such compositions as media in electroactive devices such as electrochromic and electrophoteric devices, and the electroactive devices comprised of these media.

Abstract: A display of an electrochromic type, including an active matrix substrate on which a plurality of pixel electrodes corresponding to pixels are arranged in a matrix form; a counter substrate which is provided with a transparent electrode that is common with respect to a plurality of the pixel electrodes; and an electrochromic material which is sandwiched between the active matrix substrate and the counter substrate, and is colored in a boundary either between itself and the pixel electrode or between itself and the transparent electrode; wherein the pixel electrode other than an electrode-exposed part which contacts with the electrochromic material is covered with a transparent protective film; and the electrode-exposed part has a different area from the area of the part onto which a current generated between the transparent electrode and the pixel electrode concentrates, out of the transparent electrode.

Abstract: It is possible to reduce the size of a magneto-optical device, increase the speed of optical control, simplify power supply structure and its control, and maintain a Faraday rotation angle in an arbitrary state even after shut-off of the excitation current. The magneto-optical device includes a magnetic yoke (10) made of a high-permeability magnetic material, the magnetic yoke including a tabular portion (16) and four pillar portions (18) protruding from one side of the tabular portion (16), a coil (12) wound on each of the pillar portions, and a magneto-optical element (14) arranged in an open-magnetic-circuit region surrounded by the end portions of the four pillar portions. A magnetic field obtained by a coil is applied to the magneto-optical element.

Abstract: A microelectromechanical device array apparatus is provided and includes: an device array one-dimensionally or two-dimensionally arranged with devices including a movable portion having movable electrodes and fixed electrodes facing to the movable portion for displacing the movable portion to one of two different positions; and a drive circuit for inclining the movable portion by writing an device-displacing signal to the fixed electrodes and applying a control voltage to the movable electrodes when the device in a first state of controlling to displace the position of the movable portion from one to the other of the two different positions and the device in a second state of controlling to maintain the position of the movable portion at one position of the two different positions, there is brought about a state in which the device in the first state crosses over pull-out and the device in the second state does not cross over the pull-out.

Abstract: A medium for electrophoretic display using a liquid for electrophoretic display which can reversibly change a visible state by action of an electric field includes a medium comprising each independent structures of microcapsules or cells filled with a liquid for electrophoretic display comprising at least alkylpolyetheramine having a structural unit represented by a specific structural formula, one or more kinds of fine particles, a dispersant and a dispersion liquid medium, wherein the fine particles contain fine particles subjected to surface treatment for making lipophilic. Also, an electrophoretic display device includes a display device comprising a pair of substrates in which a light-transmitting electrode is formed on at least one substrate and the medium for electrophoretic display described above between the substrates.

Abstract: A display medium for an electrophoretic display device includes a liquid system, at least one thermally reversible gelling agent, and at least one set of particles exhibiting a color. Inclusion of the gelling agent enables an image formed in the display device at an elevated temperature of about or above the melting point of the gelling agent to be fixed in a gel state, e.g., at temperature of about or below a gel point of the gelling agent. The image thus has stability, even in the absence of an applied electrophoretic field.

Abstract: There is achieved an optical channel monitor capable of preventing deviation of an image formation position due to variation in ambient temperature.

Abstract: A system, apparatus and method are described for controlling the gain across one or more amplifier nodes within an optical span. In one embodiment, a fast local amplifier constant gain control loop is provided that maintains a constant gain across an amplifier node for each of the channels within an optical signal. A slow link level gain setting control loop is provided to set and/or adjust the target gain on the amplifier node(s). A gain adjust sequence is performed by the slow link level gain setting control loop to adjust the target gain(s) in response to various events and mechanisms. A “time of flight” protection method is also provided to ensure consistency between the fast local amplifier gain control loop and the slow link level gain setting control loop.

Abstract: Provided are a tellurite glass composite, an optical waveguide, and an optical amplifier using the tellurite glass composite. The tellurite glass composite includes an entire composite including 25(mol %)?TeO2?90(mol %), 1(mol %)?T1O355(mol %) or 1(mol %)?T2O3?40(mol %), 0(mol %)?ZnO?35(mol %), 0(mol %)?M2O?35(mol %), and 0(mol %)?Bi2O3?20(mol %). Here, T1 includes a transition metal Mo, T2 includes a transition metal W, M2O includes Li2O, Na2O, or two or more of Li2O, Na2O, K2O, Rb2O, and Cs2O including metals having +1 valence electrons, and amounts of M2O and ZnO are not simultaneously “0.

Abstract: An optical filter includes a transparent substrate, a first film stack and a second film stack. The first and second film stacks each includes a number of high refractive index layers and a number of low refractive index layers alternately stacked one on another. The first film stack is defined as (HL)7(0.76H0.76L)6, and the second film stack is defined as 0.5(HL)(1.3H1.3L)9(HL)8, wherein, H represents a high refractive index layer having a base optical thickness equal to one fourth of a first reference wavelength associated with the optical filter, L represents a low refractive index layer having a base optical thickness equal to one fourth of a first reference wavelength associated with the optical filter, the expression enclosed in each parenthesis represents a filter cavity, and the superscript represents the number of repetition of the expression enclosed in that parenthesis.

Abstract: An optical filter for screening out infrared and ultraviolet light includes a transparent substrate and a film stack formed on the substrate. The film stack includes a number of high refractive index layers and a number of low refractive index layers alternately stacked one on another. The film stack is represented as follows: (3.5H3.5L)7(2.5H2.5L)7(HL)6(0.76H0.76L)6, wherein, H represents a high refractive index layer having a base optical thickness equal to one fourth of a reference wavelength associated with the optical filter, L represents a low refractive index layer having a base optical thickness equal to one fourth of a reference wavelength associated with the optical filter, expressions enclosed in each parenthesis represent filter cavities, and superscripts represents the number of repetitions of the expression enclosed in that parenthesis.

Abstract: A microscopic imaging system includes a receiving means (2) for receiving an article (4) to be imaged, a linear optical detector (16), focussing means (10) for focussing an image of an article in the receiving means onto the detector, scanning means (6) for producing relative movement between the image and the detector in a direction substantially perpendicular to the axis of the detector, and an optical correcting element (14) for reducing aberrations in the image focussed onto the detector.

Abstract: A scanning microscope having a laser outputting an excitation laser beam and a fiber member having a first core and a second core. The second core is generally disposed within the first core and is operable to receive the excitation laser beam from the laser and transmit the excitation laser beam to a sample to be tested. A moveable stage supports an end of the fiber member and/or a sample to be tested and is operable to move the end of the fiber member and the sample to be tested relative to each other.

Abstract: A system for mounting a sign or graphic display to a structure allows rotation of the graphic display and provides for automatic return to the initial orientation.

Abstract: The invention relates to a stereo microscope, which as a microscope used for operations comprises a viewing output for a surgeon (41) and at least one additional viewing output for an assistant (40). The stereo microscope is characterized by shutters (17a to 20b) for selectively screening off object information.

Abstract: A projection screen comprises a red-reflecting particle layer, green-reflecting particle layer and blue-reflecting particle layer sequentially stacked on a substrate. In each particle layer, particles are accumulated by eleven cycles in a regularly alignment such as close-packed structure. Diameter of red-reflecting particles is approximately 280 nm, diameter of green-reflecting particles is approximately 235 nm, and diameter of blue-reflecting particles is approximately 212 nm. Each particles layer is accumulated by self-organized technique. The substrate used here can absorb light of wavelengths other than those of red, green and blue three primary colors.

Abstract: The present invention provides a Fresnel lens sheet that scarcely makes the projected image distorted, and others. The Fresnel lens sheet has a plurality of unit total reflection Fresnel lenses arranged on the light-entering side, each unit lens having a light-entering surface and a total reflection surface that totally reflects a part of or all of the imaging light that has passed through the light-entering surface to deflect the light in the desired direction. This Fresnel lens sheet is formed so that it fulfills the relationship H1×H1/(10×E1×T1×T1)?3L/2000, where H1 represents the length (cm) in the vertical direction of the Fresnel lens sheet; L1, the length (cm) in the horizontal direction of the Fresnel lens sheet; T1, the thickness (cm) of the Fresnel lens sheet; and E1, the modulus of elasticity (kgf/cm2) of the Fresnel lens sheet.

Abstract: A portable screen assembly includes a casing having an opening extending in a longitudinal direction on the upper surface thereof and formed by a first and second case members that extend in the of longitudinal direction and are separable from each other, a spring-biased roll rotatably mounted to the casing, a screen wound around the spring-biased roll in storage and pulled out from the opening in use, a top bar fixed to one end of the screen and used also as a cover body to close the opening in storage, and an extendable column having one end erectably pivoted at a center part of the side face of the casing and, in an erected state, holding the pulled out screen in a stretched state. Thus, the portable screen assembly having reduced size and weight, capable of being easily handled and formed in a simple structure can be provided.

Abstract: A three-dimensional image display device is disclosed. In one embodiment, the device creates an effect of a three-dimensional image floating in the air by projecting a two-dimensional image to a free space in a form of a three-dimensional image. According to one embodiment of the invention, the device can be implemented with a minimal space in the structure of a conventional vending machine, comprising a minimal number of components and low-cost parts. It is possible to produce a large quantity of three-dimensional image display devices at a low cost.

Abstract: An anti-condensation arrangement for an optical apparatus including a window mounted in a housing comprises an isolating member sealed around an end of an image collecting device of the optical apparatus and around a perimeter of the window, the isolating member substantially preventing airflow between a portion of the housing surrounding the isolating member and a space enclosed by the isolating member.

Abstract: A vibration-proof zoom lens comprises a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a positive fifth lens group, which are disposed in this order from a subject side. The second lens group moves toward an image side at a time when magnification changes from a wide-angle end to a telephoto end. The fourth lens group moves to correct variation of an image plane at the time of magnification change. The first, third and fifth lens groups are fixed. The third lens group is composed of first to third subgroups. When vibration occurs, the second subgroup is moved in a plane perpendicular to an optical axis to correct an image position so that an image blur is prevented.

Abstract: A method of designing an aspheric ophthalmic lens with both refractive and diffractive powers that is capable of reducing chromatic aberration and at least one monochromatic aberration of an eye comprises combining aspherical refractive and diffractive surfaces, selecting an appropriate eye model, establishing a design lens having at least one aspheric surface with a capacity to reduce monochromatic aberration in said eye model, establishing a diffractive lens element that corrects for chromatic aberration of the model eye; and adjusting the lens surface design in order to obtain a suitably high polychromatic image quality in a form that is weighted to comply with a spectral merit function.

Abstract: An optical diffraction grating having a superior ultra-precise non-planar surface shape desired in extremely sensitive and complex optical imaging devices (e.g. spectrometers or hyperspectral imagers) is provided. The optical diffraction grating comprises a substrate having a plurality of substantially parallel grooves, wherein each of the grooves includes a plurality of substantially parallel sub-grooves. A non-planar substrate surface shape is defined by a combination of the grooves. A groove profile is defined by a combination of the sub-grooves within a corresponding one of the grooves. In a preferred method of manufacturing the optical diffraction grating, a rotating spindle technique would be employed.

Abstract: A scanning lens for an imaging optical system converges a beam emitted by a light source and deflected by a deflector on a target surface to form a beam spot scanning in a main scanning direction thereon. The scanning lens includes a plastic lens formed by injection molding, which has a diffractive lens structure on at least one surface thereof. The diffractive Wens structure has a plurality of annular zones arranged concentrically about a rotational axis. Each annular zone has a diffracting surface that diffracts the light beam passing therethrough. The diffractive lens structure has stepped surfaces each connecting adjoining diffracting surfaces In a plane including the rotational axis and parallel with the main scanning direction, the stepped surfaces are inclined with respect to the rotational axis so that stress working between a metallic molding for the plastic lens and each of the stepped surfaces in demolding is reduced.

Abstract: A diffraction grating with periodically arranged protrusions and grooves at a relatively narrow pitch and improved diffraction efficiency is disclosed. The protrusions of the grating are made of a material whose index of refraction is greater than that of the grooves, and the ratio of the width D of the protrusion to the pitch ? of the protrusion is set equal to or less than 0.4 (D/??0.4).

Abstract: An optical device generated by interferometric lithography, in the form of a surface relief pattern that diffracts light, to be used mainly in optical security, produced by optical systems compliant with the Schimpflug and hinge Rules containing: two identical lenses L1 and L2, two physical object location B1 e B2 and one image plane A1?A2. No physical mask is needed throughout the origination process, thus eliminating any kind of border effects. The device actually implements an in-plane focused hologram, with a complex surface pattern of valleys and ridges with a non-trivial generating function, which is, by itself, both an additional security feature of the device and its fingerprint. The time to generate the optical device is proportional to the number of colours specified for the reference geometry and not depend on the overall area of the optical device.

Abstract: An exemplary prism sheet (300) includes a substrate (301) having an incident surface (302) and an emitting surface (303) opposite to each other and a plurality of parallel V-shaped grooves (304) provided at the emitting surface, each of the V-shaped grooves maintains an angle relative to a main side of the substrate, and the angle is in the range from 5° to 44.9°. An exemplary prism sheet module (500) includes a first prism sheet (510) above a second prism sheet (520), and at least one of the first and second prism sheets includes a substrate, the substrate includes an incident surface and an emitting surface opposite to each other, and a plurality of parallel V-shaped grooves provided at the emitting surface. Each of V-shaped grooves maintains an angle relative to a main side of the substrate, and the angle is in the range from 5° to 44.9°.

Abstract: An imaging optics capable of compensating for chromatic aberration is provided with a light shielding means in a surface peripheral area of a certain lens element in a lens system so as to block a light flux of a specified wavelength range, thereby eliminating chromatic aberration in halo of the light flux of the specified wavelength range when it passes the periphery of the lens system. Thus, the invention provides the imaging optics that, without an increase in the number of pieces of lens elements and without a use of an expensive specified low-dispersion glass material, in contrast with the prior art imaging optics of the same optical performances, well compensates for chromatic aberration, especially, in halo.