Abstract: A method for automating measurement of an optical property of a sample includes selecting a measurement aperture around a reference point on the sample (38), generating a set of grid nodes that fall within the measurement aperture (68), calculating the radial distance of each node with respect to a reference point within the measurement aperture, and calculating the angular position of each node with respect to the vertical. The method also includes moving a light source (32) and a light detector along the vertical and rotating the sample to measurement positions in which the light source and the light detector are aligned with one of the nodes in the measurement aperture, and measuring the optical property at the measurement position by energizing the light source and interrogating the detector. The calculated radial distances and angular positions are used to control positioning of the light source and the light detector and rotation of the sample.

Abstract: Methods and apparatus for optical Stokes polarimetry are provided. A polarimeter according to this invention includes a rotatable waveplate, including a variable birefringent material, and a polarizer optically downstream from the waveplate. The polarimeter can be integrated into a guided wave structure.

Abstract: Disclosed is a pattern forming method, in which a mask blank for preparation of a photomask is exposed in a desired pattern to form a mask pattern on the mask blank. Position measuring marks are formed on the diagonally facing corners of a main surface of the mask blank to detect a defect on the main surface of the mask blank. The relative positions of the detected defect and the mask pattern that is to be formed on the mask blank are compared, and the pattern position is selected such that the defect overlaps with the pattern. Then, the position measuring marks are measured to calculate the exposure position, and exposure treatment is applied to the selected position.

Abstract: For the colorimetric measurement of a two-dimensional original, the original is photoelectrically scanned pixel by pixel in a first step by way of a color-enabled photoelectric scanning device. A digital color representation of the original is produced from the thereby obtained scanning data. In a second step, suitable measuring positions are determined from the digital color representation of the original by way of a computer using image processing methods. In a third step, the color measuring head is automatically moved under the control of the computer to the so determined measuring positions and the original is colorimetrically measured at those measuring positions. The color data obtained thereby can be further processed, for example for the generation of apparatus profiles for the colorimetric control of output apparatus. The scanning device is preferably a high resolution flatbed or autofeed scanner or a digital camera. The color measuring head is preferably a spectral measuring head.

Abstract: An apparatus is provided for optically inspecting containers of liquid solutions. The apparatus includes a fixture for gripping the container and a conveyor or indexable table for moving the fixtured container into alignment with a camera or other optical inspection device. The apparatus further includes a vibrator at the inspection station. The vibrator causes the container of the liquid solution to vibrate sufficiently for extraneous material in the solution to move into a position that permits accurate visual inspection.

Abstract: An optical system for simultaneously compensating a source drift of a light source and a detector drift of a light detector includes a test location, a first beam path from the light source to the test location, a second beam path from the test location to the light detector. First and second beam paths are arranged to intersect at a beam crossing. A calibration sample having a known reflectivity is positioned at the test location and illuminated by a probe beam generated by the light source. A known response beam of the calibration sample is used for calibrating the light source and the detector. A reference sample is placed at the beam crossing and illuminated by the probe beam. In response, the reference sample sends a reference beam along the second path length, which is used for compensating the source and detector drift.

Abstract: This invention relates to a method and device for performing non-destructive measurements of residual stresses in an investigation area of an object based on use of optical holographic interferometry technique. The holographic interferometer is divided into a holographic probe which contains means for illuminating the investigation area of the object by coherent light, collecting the coherent light that scatters off this investigation area and means for performing a non-destructive dislocation release pulse of the residual stresses in a small region of the investigation area by exposing the object to an electric high currency, and a holographic camera which contains means for formation, registration, and development of a hologram and for formation of an interferogram of the investigation area of the object.

Abstract: A system and method is provided which suppresses relative intensity noise in a fiber optic gyroscope by taking advantage of the frequency response of erbium fiber. In operation, the gain provided by the erbium fiber is added to the gain of the other components in the feedback loop to provide for stable loop performance up to about 250 kHz. The frequency response of the erbium fiber of about 3 kHz also provides a 6 db per octave roll-off, which, when used in a negative feedback control loop for controlling the current flowing to the gyroscope light source, allows for a relative intensity noise control loop with a bandwidth much greater than 3 kHz; this may be used in high performance gyroscope applications.

Abstract: Interleavers, based on a Michelson interferometer with a Gires-Tournois (GT) etalon in each arm, are becoming popular in the filtering of light in the fiber optics telecommunications industry. As the channel spacing becomes closer together, e.g. 50 GHz or 25 GHz, dispersion compensation becomes an important factor in the choice and design of a system. The present invention solves the problem of increased chromatic dispersion by utilizing multi-cavity Gires-Tournois (MCGT) etalons, wherein the dispersion from one MCGT is used to compensate or cancel the dispersion from the other MCGT. In an optimum design for a dual cavity GT etalon, the dispersion profile of the first MCGT will have a similar amplitude and frequency as the dispersion profile of the second MCGT, only shifted by half the period so that the positive slopes of one profile are aligned with the negative slopes of the other profile.

Abstract: The present invention provides a method of testing micro-electrical mechanical mirrors including simultaneously applying a voltage to each of a plurality of such mirrors to tilt each of the plurality to a deflection angle, and simultaneously deflecting a beam from each of the plurality using an interferometer to simultaneously determine an accuracy of the deflection angle of each of the plurality. In addition, a method of manufacturing micro-electrical mechanical mirrors is also disclosed.

Abstract: The phase (and amplitude) of a wave front may be accurately measured using knowledge of the wave front of an optical field generated by an optical element, permitting the determination of the spatial transfer function of that optical element. As a device under test is scanned across an aperture plate having slits, variations in the relative amplitude and phase of light passing through the slits are affected by the optical properties of the device under test, in turn affecting the interference pattern at a detector. Changes in the amplitude and phase of the detected signal are directly and uniquely related to the transfer function of the device under test.

Abstract: According to an aspect of the present invention, a circuit is provided for determining the wavelength and power of a given optical signal across a wide dynamic range. The wavelength and power determinations are performed by logarithmic ratio amplifier in concert with a digital signal processor that utilizes representative equations of the measured optical signal.

Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.

Abstract: A surface shape measurement apparatus for measuring a shape of an object to be examined by a simple mechanism for rotating a reference grid. The apparatus comprises a stage on which the object is rested, a reference grid disposed in parallel to the stage, illumination means for illuminating the reference grid and projecting an grid pattern onto the object surface, photographing means for photographing the grid pattern projected onto the object surface through the reference grid and obtaining an image of moiré fringes, rotation means for rotating the reference grid about an axis normal to a grid surface of the grid plate, and analysis means for analyzing the shape of the object surface based on information about a rotation angle of the reference grid and intensity of the moiré fringes.

Abstract: A method and apparatus for outputting an electronic document, in which separation pages are automatically interleaved between successively printed pages of the electronic document. In one embodiment, the invention provides a method of printing an electronic document on transparency film using a computer printer having at least two (2) paper source trays. The method may involving modifying an existing printer driver associated with the printer to cause the printer to print pages of the document on sheets of transparency film obtained from a first paper source tray, and to automatically interleave blank sheets obtained from a second paper source tray between successively printed pages. For example, an existing printer driver is modified by automatically generating a new computer printer driver based on an existing printer description file that is associated with the existing printer driver, to redefine pagination and paper source tray attributes of the description file.

Abstract: Image data is stored on a removable external card together with previous printing information relating to printing of this image data. Accordingly, when printing identical with that executed previously is carried out, the need to make printing settings again is eliminated by performing printing based upon the stored information. By further storing printing paper information in the external card, information regarding a new type of printing paper can be registered in an image processing apparatus with ease. This makes it possible for the apparatus to print properly even on a new type of paper.

Abstract: In order to prevent wasting of printing paper by reducing blank portions on the paper when an image to be printed is smaller than the paper, the size of a plurality of images designated to be printed out is compared with the size of the printing paper, the plurality of images are laid out so that as many as possible will fit on one sheet of the printing paper, and the images thus laid out are printed.

Abstract: A method for generating a secondary image, being a first body of data from an initial document, onto a second body of data from the initial document, to produce a final document. The method includes identifying within the initial document the first and second bodies of data. The initial document is then formatted into an initial digital document file capable of being processed by the document producer into the final document. The first body of data is stored in a computer readable memory as a secondary image data file, and the second body of data is stored in the memory as a primary image data file. The secondary image data file and at least a portion of the primary image data file are then combined in the document producer to generate a digital page of the finished document, which is then generated by the document producer as the final document.

Abstract: A method and system are provided for preparing printed matter. The method is particularly well-suited for the Internet. Herein, an account holder provides information related to a desired type of printed matter to a printer. The printer collects data from a user to complete a template, and from the completed template, a viewable proof of the printed matter is instantaneously provided to the user. If the viewable proof is approved by the user, the printed matter is ordered to be printed. If not approved, the user makes changes to the data provided to instantaneously generate a new viewable proof. The process is repeated until the printed matter is ordered to be printed.

Abstract: This invention allows both a plateless textile printer that makes process color expression, and a plate textile printer to achieve equivalent color expressions. For this purpose, image data that uses an RGB pallet is converted into YMCK image data using a correction table. An ink-jet textile printer (14) prints on textile on the basis of the converted image data. On the other hand, the image data that uses the RGB pallet is sent to a plate separation data generation unit (15), and is separated into binary plate data, the number of which is the same as the number of ink colors of the ink-jet textile printer, using an RGB/ink color tone correction table to realize the same color expression as that of screen textile printing.

Abstract: An image processing method in which an image of an original is read by an image input device, the read image data is converted to density data used when printing onto a photosensitive material, and an image is obtained on the photosensitive material by digital exposure, wherein, when the image data is converted to the density data used when printing onto the photosensitive material, the image data is corrected on the basis of parameters determined by combinations of print finish characteristics, including at least image input device characteristics, kind of original, kind of photosensitive material, and exposure amount characteristics, which affect a print image when the image of the original is printed onto the photosensitive material by an analogue exposure system. On the basis of the above parameters, the density data is obtained while the image data is corrected.

Abstract: An image can be outputted with a high sharpness without deteriorating a resolution. In order to output an image of a high picture quality while suppressing the occurrence of a moire, an exposure amount is modulated in accordance with pixel density information of the image divided into pixels of a predetermined size by an exposure amount modulating unit in a light scanning unit, thereby expressing an image dark/light state. In this case, in a highlight density region in which a pixel density is equal to or less than ⅓ of the maximum image density, the density data of two adjoining pixels is modulated by one pixel and the other pixel is not recorded. In a density region in which the image density lies within a range from ⅓ to ½ of the maximum image density, a part of the density data of one of the two adjoining pixels is transposed to the other pixel.

Abstract: A method for printing images using light black ink. The method sets a first and second threshold determined by an intensity value of the light black ink relative to standard black ink. The method then determines a gray component density value for a pixel, calculates a black generation value based upon the first and second thresholds and then generates values for other colors dependent upon the black generation value.

Abstract: The color image processor in accordance with the invention has a raster circuit 1 for receiving data about an image of multiple gray levels of plural colors, an UCR/BG circuit 2 for decomposing the image data received from the raster circuit 1 by the use of input Raster Operation codes according to color materials of plural colors, rasterizing the image data into a buffer memory 5, and generating black, and a binarization circuit 3 for binarizing raster data about each gray level and converting the data into data about images each having one gray level. If the aforementioned Raster Operation codes are other than Raster Operation codes having a base image, the raster output function, the UCR/BG functions, and the binarization function are performed simultaneously.

Abstract: Color processing architecture and algorithms (CPAA) for color laser printers process and handle incoming RGB image data effectively to achieve high performance, high quality image printing with low memory requirements. CPAA supports a new data structure for faster raster operation processing (ROP) for color laser printers. The CPAA architecture advantageously improves the flow of data through the processing pipeline to provide high speed at higher resolutions, e.g., at 600 and 1200 dpi. An advance quantizer using multilevel dithering flexibly reduces bits to support fast ROP and to enable fast conversion to CMYK data with only a simple look-up table (LUT) operation by a color matching module, while an adaptive filter maintains high image quality.

Abstract: When an image reading apparatus (1) shifts from a standby condition to a power economizing state, a buffer (15) electrically disconnects a connection path 14. Subsequently, a switch 13 electrically disconnects a power supply path 12. When the image reading apparatus 1 shifts from a power economizing state to a standby condition, the switch 13 electrically connects the power supply path 12, thereby commencing the supply of power to an image pickup section 20. Subsequently, the buffer 15 electrically connects the connection path 14. Consequently, even in a case where the supply of power to the image pickup section 20 is stopped, an electric current will not flow from the image processing section 6 to an analog-to-digital converter 22. Thus, breakage of elements included in the analog-to-digital converter 22 can be prevented. Further, when the image reading apparatus 1 is in a power economizing state, the supply of power to the image pickup section 20 and the fan 10 as well as to a light source 51 is stopped.

Abstract: The present invention is to provide an image reader including a transparent substrate, which can be used effectively for an extended lifetime. The image reader comprises a transparent substrate and a stationary image pickup opposed to the transparent substrate for reading an image of an original document while the document is being transported between the transparent substrate and the stationary image pickup. The transparent substrate can be turned around and/or upside down relative to the image pickup in order to use the transparent substrate for an extended its service time. Also, the transparent substrate includes at least one first indicator showing an arrangement order how the transparent substrate has been turned around relative to the image pickup.

Abstract: An apparatus for driving a scanner includes a driving motor which is rotated in both directions, a driving gear which is driven by the driving motor, a driving pulley which rotates a timing belt coupled to the scanner body, a reduction gear which is engaged with a gear portion of the driving pulley, a power transmitting unit for directly transferring a rotational force of the driving gear to the driving pulley or transferring the rotational force through the reduction gear to the driving pulley, where, when reading a colored image, the driving force is decelerated and then transferred to the driving pulley under the same speed of the driving motor as a case of reading a black-and-white image, in accordance with the rotating direction of the driving motor.

Abstract: A photosensor array has transfer gates that are logically divided into sections, with separate control over each section. Sequential control of the transfer gate sections, coupled with shifting the charge shift register, enables each stage of the charge shift register to accumulate charges from multiple sensor elements. Multiple scanlines are then interleaved into the charge shift register. Because charges from multiple sensor elements are accumulated, the exposure time can be reduced. Because multiple scan-lines are interleaved, the amount of subsampling for lower sampling rates can be reduced or even eliminated. As a result, the overall time required to acquire just the data that is needed for lower sampling rates is substantially reduced.

Abstract: The present invention relates to a method for controlling an image scanner for reading images by moving an image sensor. Specifically, the present invention relates to a control method for detecting the boundary between a white region and a black region formed at a predetermined place in accordance with a signal output from the image sensor and determining the home position of the image sensor in accordance with the position of the boundary. Particularly, the present invention is an invention for providing a control method for preventing erroneous recognition due to influence of external light.

Abstract: A film scanner includes a cold cathode lamp for producing visible light to scan a film containing a plurality of photographic images, an infrared source for producing infrared light to scan the film, and a detector or light sensor for sensing the visible light. The infrared light transmits the film to produce corresponding image signals. The cold cathode lamp is disposed between the infrared source and the film and the cold cathode lamp is in contact with the infrared source. In this way, before arriving at the film the infrared light is substantially uniformized by passing through the cold cathode lamp.

Abstract: An optical image and transmission composite assembly comprises an optical module, a transmission unit and a guiding unit. The transmission unit and the guiding unit are arranged on the optical module, wherein the optical module is guided and moved by the engagement of a plurality of wheels and tooth bars, or by a female guiding stage and a male guiding stage fit with the female guiding stage. The assembling effort and cost of the scanner using the optical image and transmission composite assembly can be reduced.

Abstract: This invention uses a 4-line color CCD sensor including four line sensors Y, R, G, and B. In a low-speed color read mode, outputs from these sensors are processed by A/D converters and subsequent processing units provided in one-to-one correspondence with the sensors. In a high-speed monochromatic read mode, an output from the Y sensor is divisionally processed by using A/D converters and subsequent processing units provided in one-to-one correspondence not only with the Y sensor but also with the other R, G, and B sensors. This provides an image reading apparatus usable in both the high-speed monochromatic mode and the low-speed color mode and capable of achieving high speed, high accuracy, and low cost.

Abstract: An optical device for security and anti-counterfeit applications comprises a holographic diffractive structure (8) that generates a holographic optically variable image by diffraction that consists of at least two separate substantially co-located linear regions that generate in response to white light illumination a visually observable holographic image consisting of at least two defined graphical elements and which generates in response to coherent illumination (1) at least two covert images (5, 6, 7) focussed at a separate image plane a distance away from the real physical plane of the device, each covert image (5, 6, 7) corresponding to the replay from one of the linear regions, each covert image (5, 6, 7) being separated on its image plane from the adjacent covert image (5, 6, 7) by at least its own dimensions.

Abstract: A single plate type optical unit and display device to utilize light with high efficiency in a simple method is configured so a dichroic mirror separates light into a plurality of colors, and the plurality of colors of light reflected by the dichroic mirror are beamed onto a rotating multisurface element, the plurality of colors of light emitted from the rotating multisurface element are each beamed onto different locations on the display element, and by rotating the rotating multisurface element, the plurality of colors of light are moved in one direction along the display element, and a color image is beamed from a projection lens.

Abstract: There is disclosed an optical deflector comprising an oscillating member including a movable plate allowed to oscillate, the movable plate including a coil extending along its periphery, and a magnetic field generation portion, such that the movable plate oscillates in accordance with a force generated by an interaction of a current flowing through the coil with the magnetic field generated by the magnetic field generation portion, wherein the movable plate has first and second surfaces extending in substantially parallel with each other, an imaginary plane including the first surface of the movable plate in a neutral position defines two spaces, one including the second surface of the movable plate and the other not including the second surface, and the magnetic field generation portion is positioned in the space including the second surface of the movable plate.

Abstract: A variable slit width device for a spectroscope which can be used in a narrow space, be widely variable, and be set in slit width with high accuracy. The variable slit width device includes a pair of freely rotatable rotary parts for pressing inclined guide parts of a pair of slit holders, pressing parts for supporting the pair of rotary parts, and linear guides having guide parts formed at the lower surfaces thereof and extending horizontally in a direction crossing with guide rails at right angles. The pressing parts are fixed to the linear guides, the guide rails are fitted to the guide parts of the linear guides, feed nuts are fixed to the pressing parts, feed screws are engaged with the feed nuts. Bearings are provided for rotatably supporting the feed screws, preload springs for preloading the feed nuts and the feed screws, a slit driving part for rotatably driving the feed screws, and a housing part for fixing thereto the guide rails, the bearings and the motor.

Abstract: An apparatus for modulating information bearing symbols onto an optical carrier includes a polybinary coder that operates on a binary information signal to produce an envelope compatible polybinary signal; and an optical single sideband modulator that modulates an optical carrier with the envelope compatible polybinary signal to produce a single sideband optical signal. This provides an improvement over both polybinary signaling and optical single sideband. This action combines the chromatic dispersion advantages of SSB modulation with the DC level and bandwidth reduction of duo-binary coding.

Abstract: A multi-channel acousto-optic modulator contains an integrated structure for providing active compensation for transient thermal effects. A plurality of electro-thermal elements in the form of resistive strips are interleaved with acoustic wave launching transducers, to which signals are applied for modulating respective acoustic waves launched into an acousto-optic medium. The resistive strips receive electrical signals that controllably introduce respective thermal energy components into the acousto-optic medium adjacent to the signal launch transducers, in a manner that causes the overall spatial distribution of thermal energy in the acousto-optic medium to have a prescribed characteristic. By establishing an thermal gradient characteristic across all the channels of the RF signal processor, and compensating each channel on an individual basis, the invention effectively compensates for time-dependent variations in heating, resulting in a substantially level thermal behavior.

Abstract: Tabs or stops are integrated into a membrane structure to prevent its snapdown. Features comprising two surfaces separated by a distance equal to the maximum desired range of movement are produced. When the two surfaces contact, the motion of the structure is arrested or greatly diminished by increasing its rigidity. For an electrostatically actuated MEMS structure, these features can be used to limit the range of motion such that pull-in or snapdown is avoided, greatly enhancing the reliability of the device. One key design feature is that the two contacting surfaces are maintained at the same electrical potential avoiding problems associated with electrostatic cavity discharge.

Abstract: A micromirror driver for simultaneously and independently controlling a resonant frequency and an amplitude of a micromirror. A micromirror having a plurality of grooves is supported in rotation by an elastic body. Base electrodes having a comb shape are affixed to the grooves and along an edge of the micromirror. A plurality of driver electrodes also having a comb shape are respectively engaged with the base electrodes in a gear like arrangement to electrostatically interact with the micromirror in response to applied voltages. An amplitude and a frequency of the micromirror are controlled by varying a magnitude or a waveform of one or more electrode voltages or by varying a phase between voltages applied to at least two electrodes. Accordingly, greater driving forces, a larger rotation angle of the micromirror, and independent control of amplitude and resonant frequency of the micromirror are obtained.

Abstract: A lithographic projection apparatus includes an active reflector in a radiation system providing a projection beam of radiation and/or in a projection system. The active reflector includes a body member, a reflective multilayer and at least one actuator controllable to adjust the surface figure of the reflecting multilayer, wherein the actuator exerts a substantial force component in a direction parallel to the surface figure of said reflective multilayer. The actuator may be operative to apply torques to said reflector.

Abstract: An electrophoretic composition in the form of a dispersion containing a dispersion medium, and electrophretic particles dispersed in the dispersion medium and having a color selected from white and non-white colors. The dispersion medium includes a non-polar solvent, a sulfonic acid compound soluble at least partly in said non-polar solvent, and a polymeric material soluble in said non-polar solvent.

Abstract: An optical signal having optical energy is received at an optical amplifier. The optical signal may be separated into a low frequency segment and a high frequency segment. The high frequency segment and the low frequency segment may be processed in order to determine a low frequency error signal and a high frequency error signal. The low frequency error signal may be summed with the high frequency error signal in order to generate a total error change associated with the optical amplifier.

Abstract: An optical 2R/3R regenerator is described. One or more LSOAs are used as part of the optical 2R/3R register.

Abstract: A low noise optical amplifier used in an optical communication system includes optical amplifying elements for amplifying optical signals of a specific wavelength(&lgr;) incident from their ends(F1,F2) and endowing phase difference between ASEs, optical diverging means to interfere the amplified optical signals and the ASEs output from both ends(F1,F2), first path of length(L1) to optically connect the one end(F1) to first gate(D1) of the optical diverging means, and second path of length(L2) to optically connect the other end(F2) to second gate(D2) of the optical diverging means. The first and second paths are designed with distance(L1-L2) so that the amplified optical signal causes reinforcing interference at the third gate(D3) and destructive interference at the fourth gate(D4), and the ASE causes destructive interference at the third gate(D3) and reinforcing interference at fourth gate(D4).

Abstract: The invention provides a method of making a <194 nm wavelength calcium fluoride crystal optical lithography element for transmitting wavelengths less than about 194 nm along an optical axis with minimal birefringence by providing an optical element optical calcium fluoride crystal with an input face {100} crystal plane and forming the input face {100} crystal plane into an optical lithography element surface of an optical lithography element having an optical axis, with the optical axis aligned with a <100> crystal direction of the optical calcium fluoride crystal. In a preferred embodiment, the below 194 nm transmitting optical element is a <100>oriented calcium fluoride lens. In a preferred embodiment, the below 194 nm transmitting optical element is a <100> oriented calcium fluoride beam splitter.

Abstract: The invention relates to a stereo surgical microscope comprising at least one stop (12, 20) which can interrupt a main beampath in such a way that the user can only see one image when required, wherein the image is received via a reflected-in beam path (21).

Abstract: The optical system includes a first set of optics, an optical switch and a second set of optics. The first set of optics is capable of receiving light and directing the light along a first optical path. The optical switch is capable of directing a first portion of the light to continue along the first optical path, and directing a second portion of the light along a second optical path. The second set of optics is subsequent to the optical switch and is capable of receiving the first portion of light from the optical switch, and directing that portion of light along a third optical path. The third optical path and the second optical path are substantially co-aligned. The optical system has variable magnifications and requires no moving parts.

Abstract: Glass microspheres and rear projection screens containing glass microspheres, which combine a desirable index of refraction (preferably, no greater than about 1.70) and low levels of defects (e.g., bubbles, visible haziness, frostiness, or opacity, substantially nonspherical shapes) upon formation are provided. Also provided is a coating method of placing microspheres on a film for use in a rear projection screen.