Abstract: A method and system for inspecting a semiconductor wafer. The method includes providing an illumination flux through a pattern plate and a lens to a surface of a specimen to project a pattern onto the surface of the specimen. The pattern is associated with the pattern plate. Additionally, the method includes detecting the illumination flux reflected from the surface of the specimen with a detector, processing information associated with the detected illumination flux, and generating a first image based on at least information associated with the detected illumination flux. The first image includes a first image part for the pattern and a second image part for the specimen. Moreover, the method includes adjusting the lens to a state in order to achieve a first predetermined quality for the first image part, and moving the specimen to a first position.

Abstract: An imaging apparatus according to one embodiment of the invention includes a programmable patterning structure configured to pattern a projection beam of radiation according to a desired pattern. The programmable patterning structure includes a plurality of separate patterning sub-elements, each sub-element being configured to generate a patterned sub-beam. At least one of the separate patterning sub-elements is configured to generate a patterned sub-beam whose cross-section contains regions of different intensities. The imaging apparatus also includes a combining structure configured to combine the plurality of patterned sub-beams into a single patterned image, and a projection system configured to project the patterned image onto a target portion of a substrate.

Abstract: A photosensitive area 11, such as a photolithographic sheet, in an images plane is notionally subdivided in both dimensions to form contiguous (tiled) sub-areas. Variable illumination means 1,4 provides a selected pixellated light pattern, which is directed 8, 9, 10 to fill a selected one of the sub-areas so that pixels of said pattern are, at least 15 microns across at the sub-area, and control means are responsive to an input signal representative of an image conjointly to control the production and direction of the pixellated patterns so that an entire image is produced over all of the said sub-areas. As shown, the variable illumination means comprises a light source 2 with digital micro-mirror array deflector device 4, and the sub-area is selected by lens array 8 with a shutter 10 and polariser array 11. The latter may be replaced by a two-axis steering mirror and lens array.

Abstract: The method for exposing a printing plate copies a stored model onto a printing plate. The exposure device includes at least one exposure head (1). Each exposure head (1) has a light source (3), a picture generating unit (8) and a copying optical element (9). The picture generating unit (8) includes electronically controllable micro mirrors arranged in a grid. The stored model is divided into partial images, which are shown in succession by the picture generating unit (8) and the copying optical element (9). Successive partial exposures of the printing plate are made by the at least one exposure head, which is accurately positioned at respective successive exposure positions by an electric linear drive so that individual copies of the partial images are combined into a total image on the printing plate with a position accuracy of better than 5 microns. Exposure times are shortened while maintaining copy quality.

Abstract: The invention relates to a method for triggering an exposure device for the photomechanical production of structured surfaces as a copy of an electronically memorized model, in particular for exposing printing plates, in which the exposure device includes at least one light source (3), one picture generating unit (8) comprising movable, electronically individually triggerable micro mirrors arranged in a grid, and one copying optical element (9).

Abstract: A stimulable phosphor sheet, on which a radiation image has been stored, is scanned with stimulating rays in a main scanning direction and moved in a sub-scanning direction, which is approximately normal to the main scanning direction. A read-out device photoelectrically detects the light, which is emitted by the stimulable phosphor sheet when the stimulable phosphor sheet is scanned with the stimulating rays in the main scanning direction, to obtain an image signal representing the radiation image. A light guiding mirror for reflecting the emitted light toward the read-out device is located to extend in the main scanning direction at a position in the vicinity of a position on the stimulable phosphor sheet, which position is scanned with the stimulating rays in the main scanning direction. The light guiding mirror is supported by a support member, which is formed from a metallic material and is electrically isolated from a ground, or which is formed from an electrical insulating material.

Abstract: Photosensitive material is printed in a printing/exposure unit of a photoprinting/developing machine with high efficiency. The photoprinting/developing machine includes a printing/developing section, a carrier section and a developing section. The carrier section has a sheet distributor to improve the processing capacity of the developing section. The printing/exposure section has an exposure table. If photosensitive sheets are short enough, three of them are fed onto the exposure table all at once.

Abstract: A small field scanning photolithography system uses opposing motion of a reticle and a blank to compensate for image reversal by a projection system such as a conventional Wynne-Dyson optical system which forms a reverted image on a blank. The reticle has a reverted pattern. During scanning, the reticle moves along a reverted axis in a direction opposite the direction in which the blank moves. The opposing motions can either expose a stripe on the blank or index the reticle and blank for exposure of a next stripe. In one embodiment of the invention, the reticle and blank are on independently movable precision air bearing stages. Typically, the blank and reticle move together perpendicular the reverted axis and in opposite direction along the reverted axis. The stages can move the reticle and blank different amounts to correct for shrinkage and temperature changes which cause the size of the reticle and blank to differ.

Abstract: A photographic printer for printing negative images on a negative film onto photographic paper. The printing direction can be changed over between "lateral" and "longitudinal" without changing the feed direction of the negative film. A reflecting mirror is inclined by 45.degree. with respect to the optical axis of the light emitted from a light source to the negative film and is supported to be rotatable about the optical axis. A driving unit is provided to rotate the reflecting mirror by 90.degree. about the optical axis between a reference position and a second position. Exposure stages are provided on the optical axes of the light beams reflected by the reflecting mirror when the mirror is in its reference position and second position, respectively. The photographic paper is guided through the exposure stages. According to the position of the mirror, negative images are printed on the paper at one of the two exposure stages.

Abstract: A high speed multi-magnification photofinishing printer for selectively projecting images onto a projection plane containing photographic paper at a plurality of different magnifications is disclosed herein. This printer includes means for supporting a given image bearing photographic negative, means cooperating with the negative for producing a given image bearing light beam, and a plurality of spaced apart but fixed magnification lenses, each of which is designed to project the given image bearing light beam onto the photographic paper contained within the projection plane at different magnifications. The printer also includes light beam position altering means for selectively and alternatively causing the image bearing light beam to pass through any one of the plurality of fixed magnification lenses and onto the photographic paper, whereby to selectively and alternatively project the image bearing light beam onto the paper at one of the different magnifications.

Abstract: A recording apparatus for recording images of an object on a plurality of recording media records the object images on the recording media at different reduction factors. It also records an object image independently on each of the recording media.

Abstract: A mirror driving method, and device, for a photographic printer having a mirror diagonally movable into and out of a printing light path between a photographic film and a printing lens. The mirror is moved into the printing light path for reflecting light toward a photometric system of the photographic printer during light measurement before printing. During printing, the mirror is removed from the printing light path and is stopped at a rest position. When moving from the rest position into the printing light path, the mirror is controlled to move first at a high speed and then at a low speed. When the printer operation is interrupted for a period or terminated, the mirror is locked at a lock position which is removed from the printing light path.

Abstract: A reader printer is disclosed which incorporates therein a scanning plane mirror for projecting an image in the form of a slit on a sensitive material. The sensitive material is shifted proportionately to the rotation of the scanning mirror so that the position at which the image is projected on the sensitive material will coincide with the scanning position of the sensitive material. As a result, the otherwise possible phenomenon of defocusing is precluded and the image is faithfully reproduced on a recording paper. The mechanism for rotating the scanning mirror and the mechanism for shifting the sensitive material are divided to allow production of a reader printer of a small size.

Abstract: An apparatus for forming enlarged exposures of film negatives is provided. The apparatus is adapted to be coupled to the housing of a conventional photo-processing machine without requiring permanent modification of the conventional machine. The apparatus includes a pair of magazines, one magazine of which houses a roll of unexposed paper. The unexposed paper is fed from the one magazine, vertically through the apparatus and into the other magazine. A mirror placed in the conventional machine, reflects a focussed light beam that has passed through a negative. The light beam is directed into the apparatus so that it impinges on a portion of the unexposed paper passing therethrough thereby forming an exposure of the negative on the paper. Drive motors automatically advance the paper from the one magazine to the other, upon exposure of the negative on the paper. A cutter is provided for cutting the paper when a complete reel of negatives has been exposed.

Abstract: A camera includes a holder (1) for holding an original, an optical system (10) for optically scanning the original to form an image thereof, a mechanism (6) for moving the optical system and the holder with respect to each other, and a cylindrical drum (8) for conveying sensitized material (21) in synchronization with the mechanism (6) to record the image of the original on the sensitized material (21) in a continuous slitwise manner. The sensitized material (21) is conveyed while held by static electricity or vacuum attraction. The camera is capable of variable magnification.

Abstract: A broad magnification ratio range, microform to paper printing system includes a fixed focal length objective lens, a selectively adjustable short zoom mirror assembly, a selectively adjustable long zoom mirror assembly and optical switching means selectively to exclude or include the long zoom mirror assembly to provide the optical path length needed for the magnification ratio selected. The printing system may include an aperture shutter assembly positioned immediately adjacent the image slit of the optical system, the aperture shutter assembly having two blades operative to set the aperture width therebetween to control drum exposure and also operative selectively to close the aperture therebetween to block drum exposure.

Abstract: A scanning exposure device comprises a projection lens, a photosensitive member disposed beneath the projection lens, two movable mirrors disposed with their reflecting surfaces facing upward and having asymmetrical inclinations relative to each other, and a stationary mirror disposed with its reflecting surface facing downward to form an optical path together with the movable mirrors. The two movable mirrors are driven for scanning movements so as to expose a picture image from the projection lens on the photosensitive member through a slit. Thus, an optical path is established in which the light beam projected from the projection lens located at a higher position is guided toward the photosensitive member located at a lower position.

Abstract: An apparatus including separate mechanisms for photographing documents under automatic exposure control and recording image data, such as blip marks and frame numbers, at the same time. Even when the document has been completely photographed, the photographing mechanism is prohibited from transporting the film until the image data is completely recorded. The photographing mechanism photographs the document with automatically controlled proper exposure time in accordance with the density of the document. The data recording mechansim is independent of the photographing mechanism to record the image data properly under a constant condition, irrespective of variations in the exposure time in conformity with the document density. When the image data has not been recorded despite the completion of photographing operation, transport of the film is prevented to avoid failure in image data recording.

Abstract: An image forming apparatus has a first body capable of containing a movable photosensitive member therein and having first optics for applying, in a first mode, image information light obtained in the first body to the photosensitive member and forming an image on the photosensitive member, and a second body connected to the first body and having second optics for directing, in a second mode, an image information light obtained in the second body to the first body and forming an image on the photosensitive member in the first body. The width of the image formation area with respect to a direction orthogonal to the direction of movement of the photosensitive member is smaller in the second mode than in the first mode.

Abstract: A flash exposure, full frame electrostatographic printing system is disclosed as having a document support drum and an optical arrangement for scanning a document for exposing the same to a moving photoreceptor belt. The optical arrangements for flash exposure and scanning have most of their respective parts in common. A mirror is incorporated into the optical arrangement for scanning and is movable into and out of the optical path thereof.

Abstract: A microfilming camera for taking an microimage of a document on a film. The microfilming camera comprises a main mirror disposed beneath a transparent document support for the support thereon of a document to be microfilmed, which main mirror is used to deflect the optical path of a photo-taking system, a side mirror disposed on each side of the space delimited between the document support and the main mirror, and illuminating sources positioned exteriorly of the optical path and disposed in face-to-face relationship with the respective side mirrors.

Abstract: The disclosure is directed to an image formation apparatus for producing both mirror images and normal images. The apparatus comprises an image inverting prism positionable selectively in an optical path of an image transmission device or outside thereof. The prism is so shaped as to give the same optical path length when positioned in the optical path and when positioned otherwise.

Abstract: An apparatus for the automatic microfilming of documents of different formats and the development of exposed microfilms in a continuous process. The apparatus includes a computer controlled combination of (a) an installation for the automatic insertion of documents and their transport through an exposure device from a stack of documents of a certain format, with means to adjust to a given format; (b) an interchangeable lens camera with an illumination and mirror system for the simultaneous imaging of the front and reverse side of the document and with an automatic film transport device; (c) a camera with an exposure system for the filming of titles and continuous identifications; (d) an automatic film development installation; and (e) a central guide and control system with an input keyboard, a monitor and a processor.

Abstract: A system for producing images of documents is disclosed. The system provides varying levels of illumination to different areas of the document being recorded, depending upon relative image densities across the document. A slit aperture image area is divided into a plurality of illumination zones and the image density of each zone is sensed and adjusted individually. Efficient and orderly unattended off-loading of photographed documents is accomplished by a movable drawing member over which large documents are automatically draped, properly collated. A catch tray is provided for automatically off-loading and collating smaller documents.

Abstract: Disclosed is a film cassette of a kind which contains an electrophotographic film therein and which is adapted to be loaded in an electrophotographic camera processor-reader. The film cassette includes a cassette casing formed with a reflecting-mirror insertion cavity into which a reflecting mirror is inserted in inclined relation for reflecting light emitted from a projecting light source to direct the light toward a projecting lens. Because of no necessity for incorporation of the elements including the projecting light source and reflecting mirror in the cassette casing, the size and weight of the film cassette itself can be reduced.

Abstract: Disclosed herein is a photographic printing apparatus including at least one of image-rotating lenses 25 and 26 which enables the production of prints of the same size from photographic films both of full size and half size by a 45-degree rotation of said image-rotating lenses 25 and 26.

Abstract: A variable magnification copying apparatus for obtaining a copy changed in size from an original pattern comprises an optical system having an optical axis, a movable carrier on which the optical system is mounted so as to be movable with the carrier and a D.C. motor mounted on the carrier. The carrier is reciprocable relative to a chassis of the copying apparatus in the direction of the optical axis between at least first and second position. The D.C. motor drives the carrier in a self-propelled manner relative to the chassis in the direction of the optical axis between at least first and second positions to thereby move the optical system between at least corresponding first and second positions to enable respective different sizes of the original pattern to be made at the corresponding first and second positions of the optical system.

Abstract: A desk-top camera/processor-reader apparatus for electrophotographic film includes a primary optical system of three fixed mirrors (24, 26, 28), and a pivotable mirror assembly (36) for defining optical paths between a copyboard station (12) and the microfilm (30) as well as between the microfilm (30) and a rear-projection screen (18). The pivotable mirror assembly (36) is movable between two extreme positions, the first position (36') being the camera/photographing mode, and the second position (36") being the reader/viewing mode. Camera/photographing and reader-projection lamps (42, 56) are provided for alternative energization and illumination of the copyboard station original documents and the microfilm (30).

Abstract: An electrophotographic copying machine capable of making a two-dimensional copy either from a two-dimensional or three-dimensional object is provided. In accordance with the present invention, if a three-dimensional object has portions which cannot be brought into contact with the top surface of the contact glass plate of the copying machine, adjusting means adjusts the focal distance to the location of such non-contact portions. The adjusting means may be any element of the optical system which is constructed to be shiftable to change the focal distance to a point of interest above the contact glass plate. Alternatively, the adjusting means may include a new element additional to the optical system.

Abstract: A copier has a movable housing which accommodates a support for an original to be copied, a source of illumination for the original, a lens system for forming an image of the original and a support for photosensitive material which is to receive the image. The housing has an opening in one of its sides and carries a hinged lid for lighttight sealing of the opening. A reflector is pivotally mounted inside the housing in the vicinity of the opening and can be moved between an operative position in which it intercepts the image from the lens system and an inoperative position in which it does not. When an image of normal size is required, the reflector is in its inoperative position and the image is projected onto the photosensitive material located inside the housing. When an image of large size is required, the reflector is brought into its operative position and the opening in the housing is uncovered.

Abstract: A microfilm camera employs a reciprocating lens to optically arrest motion of documents traveling in a high-speed stream for photographic exposure onto stationary, incrementally advanced photographic film. The reciprocation of the lens is controlled by a closed loop servo system. To enhance performance of the servo system, the lens is supported by a four-bar linkage comprising relatively stiff light-weight arms interconnected by crossed leaf spring hinges.

Abstract: A reflection sensing apparatus detects the prior exposure history of an annotatable archival microfiche film card frame. A light source used to expose the microfiche to the record image is positioned to convert a reserved sensing area, which is outside the record image but within the frame, from an opaque and reflecting area to an irreversibly clear and transparent area upon exposure. The reserved area of the microfiche film card frame is interrogated by automatic photoreflection sensing immediately prior to exposure of a given frame to disclose its prior exposure history. Suitable warning systems indicate the imminence of multiple exposure, and an automatic disabling feature prevents accidental re-exposure. A manual override means controlled by the operator must be actuated to allow re-exposure of a previously exposed frame. An alternative pre-exposure sensing of the reserved area by optical transmission methods is described.

Abstract: A system for microfilming documents that employs microprocessor control to insure fault-free operation. The aspects of operation; such as document present, size of document, size of photographic mask, the exposure parameter, and system "ready", must meet necessary criteria, or the microprocessor will halt operations and present a human-readable response as to the cause.Substitutional tables for supporting documents are available, to relate to the characteristics of the document.Simultaneous conflicting commands are executed sequentially according to a priority sequence.

Abstract: A reprographic camera suited for use in daylight conditions has a light-tight casing mounted on its rear-side in which casing is provided with dispensing means for dispensing the required amount of photosensitive material from a supply roll contained therein, a positioning mechanism for positioning the photosensitive material in the middle of the image plane and an optical processing station. The dispensing and positioning are controlled by synchronous motors which are energized for an adjustable period of time which depends on the length of sensitive material to be dispensed and positioned.

Abstract: A compact and transportable apparatus for making instant prints from slides or transparencies, without the need for darkroom facilities, comprising: a housing, having a lens-shutter assembly and means for attaching a film pack in operable relation to the lens-shutter assembly; a slide station, having means for holding a slide or transparency to be copied; and, a light diffuser assembly, for evenly illuminating the slide during copying, whereby an optical path is formed in said diffuser assembly, passing through the slide or transparency, the lens-shutter assembly, and onto said film pack. The overall size of the apparatus may be reduced by interposing at least one mirror in the optical path.

Abstract: A set of construction units or elements forming the subject of the invention permits the construction of various kinds or optical projection apparatus which are suitable for copying passages of literature and the like so as to produce in this way a collection of technical literature, for example in the form of a card index, for continuously supplementing the user's knowledge and for facilitating his scientific activities.

Abstract: Methods of and apparatus for photographing pages of a book, which is stitched and bound so as to form a seam separating adjacent sequential pages, enable one to photograph the book on a strip of film with the pages sequentially ordered and oriented in the same direction. Essentially, the apparatus for practicing the method includes a camera which is mounted on a housing that has a hollow member with an aperture or opening that fits over a single page of the book. The camera is mounted for rotation relative to the housing so that after one page is photographed, the camera may be rotated 180.degree. to maintain the orientation of the film strip in the same direction as the first page when the housing and book are rotated relative to one another through 180.degree. to register a subsequent page with the housing. Rotation of the housing and book relative to one another may be accomplished by holding the housing still and rotating the book 180.degree. or by holding the book still and rotating the housing 180.

Abstract: Optical projection apparatus utilizing a pulley and cable mechanism for positioning optical components thereof which comprises a fixed pulley means, translatable pulley means and cable means entrained about the foregoing means. A clutch is provided to selectively preclude rotational movement of the fixed pulley means while translational movement is imparted to the translatable pulley means to thereby effect repositioning of the translatable pulley means relative to the fixed pulley means. An optical component fixed for movement with the translatable pulley means and an optical component fixed for movement with the cable can thereby be repositioned relative to each other by effecting translational movement of the translatable pulley means while simultaneously preventing rotational movement of the fixed pulley means.

Abstract: Light reflected from hard copy is reduced to microimage size and applied at an imaging and developing station to a dry-process mask film strip which is photosensitive to the reflected light and which is developed by heat to provide microimaged transparencies therein. Such microimaged transparencies in the mask film strip are transferred in an image transferring station to a dry-process microform film to provide imaged microform records therein which conform to the transparent microimages in the mask film strip and which have archival properties. The imaging and developing station includes a platform for receiving the hard copy and a projection means for applying the reduced microimage of the hard copy to the mask film strip. Projection means are provided for expanding and projecting an image of said desired imaged microform record in the microform film in expanded normal size onto the platform for viewing the same.

Abstract: A document reproduction machine having a multiple range of magnifications employs a scanning optical system which is controlled as to scanning speed and distance of travel by the selected magnification. In the higher reduction copying ranges the speed of the scanning optical system is automatically increased in proportion to the selected magnification reduction, but the increase in scanning distance is limited to the platen size. Multiple cams are employed for each range of magnification, and means are provided to change the scanning drive means between the multiple cams.

Abstract: A document photography system photographs the obverse and reverse faces of a moving document by tracking the document with a moving lens. The motion of the lens is in timed relation to the velocity of the document and in dimensional relation to the reduction of the lens. The lens is supported in a flexural mounting which allows the lens to be displaced upon the application of motive power. Motive power is provided by a rotational motor which has its output translated to rectilinear motion by mechanical linkage. The motor output is fed back by an optical tachometer to a phase-locked servo system to maintain uniform, linear lens motion.

Abstract: A slide viewer/copier operable in a viewing mode for projecting an image of a slide transparency film unit onto a viewing screen for viewing and a copy mode for projecting an image of the slide onto self-developing film unit for exposure and for processing the film unit to produce a photographic copy of the slide.

Abstract: Apparatus for reformating previously photographed data including a single light source and a mirror system for directing the light from the source in first and/or second mutually perpendicular axes which intersect at a point. Developed photographic roll film is advanced in a first plane past a first location which is spaced from the intersection point on one side thereof, the first axis passing through the first location and being perpendicular to the first plane. Developed photographic slides are positioned at a second location in a second plane perpendicular to the first plane, the second location being spaced from the intersection point on one side thereof and the second axis passing through the second location and being perpendicular to the second plane.

Abstract: Apparatus for optically copying to a desired scale with good resolution reproductions of small film images. Includes the equivalent of a filmstrip/slide or animation stand apparatus, a reproducing camera mounted upon an upright track support for elevational adjustment and having the axis of its focally adjustable lens and its gate arranged substantially downward, and a lateral tabletop supported below the camera lens for interception of the axis of the latter thereby. Means define an internal chamber which has a lateral bottom wall and an entrance upright sidewall with a top portion of this means having a large opening down through which the axis of the reproducing camera lens extends to the top face of the bottom wall and with the entrance wall having a beam entrance window.

Abstract: A device for successive reproduction of original image information to be used in a recording apparatus of a type, wherein the device includes a reciprocating table for carrying an original. The device is generally constructed with a movable table which reciprocates over the original carrying table, and on which information to be changed and selected is placed. A mechanism sequentially and automatically shifts the movable table by a driving force of the reciprocating motion of the original carrying table and thereby selectively changes the information; the shifting and changing mechanism is constructed with a plurality of mutually engaged links, wherein one of the plurality of links is displaced by the reciprocating motion of the original carrying table so as to move the movable table, and, by making variable the engaging length of at least one of the mutually engaged links, the moving distance of the movable table is made variable.

Abstract: A microfilm camera uses an instant imaging film, such as a vesicular film. Simultaneously with the exposure of the film, a small blip is recorded along the length of the film. On readout, the camera may be set to count the number of blips and thereby stop a searching reader at a preselected frame. The invention is primarily directed to a circuit for controlling the recording of the microfilm images and the blips on such instant imaging or vesicular film.

Abstract: A document filming camera for placing successive images of documents or the image of a continuous document on a strip of film and for adding recording marks along the edge of the film indicating the position of the frame on the film exposed to a document and for placing marks at intervals along the film when filming a continuous fan-fold document, as produced by a computer, to indicate the location of each successive page of the document.

Abstract: A microfilm camera using an instant image film, such as a vesicular film, is herein disclosed. Instant developing stations and an associated read-out optical system are positioned in the path followed by the film as it travels through the camera. After the film is developed, its image is projected through the optical system onto a display screen. This way the operator may see the images immediately after they are formed on the film and rephotograph any defective image immediately.

Abstract: A recorder, as for photographing original documents on microfiche, the documents selectively having information on one or both sides, which information is to be successively recorded at high speed. After initial transport by a feed belt, a first vacuum-retaining belt having document-present actuated controls moves the document to a photographing position. Thereafter this belt is reversed in direction and the document is taken from the first belt to a second vacuum-retaining belt by pneumatic force. Adhering to the second belt, the document is rotated 180.degree., side for side, and discharged again to the first belt. A second forward motion of the first belt returns the document to the photographing station, second side up. Further forward motion discharges the document. The images upon the fiche have the same orientation for both sides of the document for easy reading. Typically, one-sided documents are turned over, but are not photographed on the second (blank) side.

Abstract: A photosensitive area 11, such as a photolithographic sheet, in an images plane is notionally subdivided in both dimensions to form contiguous (tiled) sub-areas. Variable illumination means 1,4 provides a selected pixellated light pattern, which is directed 8, 9, 10 to fill a selected one of the sub-areas so that pixels of said pattern are, at least 15 microns across at the sub-area, and control means are responsive to an input signal representative of an image conjointly to control the production and direction of the pixellated patterns so that an entire image is produced over all of the said sub-areas. As shown, the variable illumination means comprises a light source 2 with digital micro-mirror array deflector device 4, and the sub-area is selected by lens array 8 with a shutter 10 and polariser array 11 10. The latter may be replaced by a two-axis steering mirror and lens array.