JP6546868B2 - VCSEL-based variable image beam generator - Google Patents

Description

  The present invention relates to imaging systems, and more particularly to single pass imaging systems that utilize high energy light sources for high speed imaging.

  Laser imaging systems are widely used to generate images in applications such as electrophotographic printing, mask and maskless lithographic patterning, laser texturing of surfaces and laser processing equipment. Laser printers often use a flatbed x-y vector scan for cutting applications, whereas laser imaging systems use a flatbed x-y vector scan while sweeping the laser perpendicular to the process direction by utilizing a polygon or galvo scanner Use a raster optical scanner (ROS).

  One of the limitations of the laser ROS approach is that there is a design trade-off between image resolution and the lateral extent of the scan line. These tradeoffs result from optical performance limitations at scan line poles such as field curvature. In practice, it is extremely difficult to achieve a resolution of 1200 dpi over a 20 '' imaging area with a single galvanometer or polygon scanner. Furthermore, a single laser head ideal for large area coverage driven motorized in x-y flatbed architecture is too slow for the fastest printing process.

  For this reason, monolithic light emitting diode (LED) arrays up to 20 '' wide have imaging advantages for wide electrophotography. Unfortunately, current LED arrays can only provide power levels of 10 milliwatts per pixel, and thus are useful only for some non-thermal imaging applications such as, for example, electrophotography. In addition, LED bars have differential aging and performance variations. If a single LED fails, the entire LED bar needs to be replaced. Many other imaging or marking applications require much higher power. For example, laser texturing or cutting applications may require power levels in the range of 10W to 100W. Therefore, LED bars can not be used for these high power applications. Also, it is difficult to extend the LED to higher speeds or resolutions above 1200 dpi without using two or more rows of staggered heads.

  There are high power semiconductor laser arrays in the range of 100 mW to 100 watts. In most cases they are present in the form of a 1D array, such as on a laser diode bar of about 1 cm in full width in most cases. Another type of high power directional light source is a 2D surface emitting VCSEL array. However, none of these high power laser technologies allow the closest laser pitch to be compatible with imaging resolutions of 600 dpi or higher. In addition, any of these techniques allow for fast individual control of each laser. Therefore, high-power applications, such as high-power overhead projection imaging systems, often use high-power power supplies such as lasers combined with spatial light modulators such as Texas Instruments DLPTM chips or liquid crystal arrays. use.

  DLP-based approaches are attractive in many respects, but have some drawbacks. First, high power lasers must be fully on to form even low saturation images that require only a fraction of the laser energy. Most of the laser energy is diverted to the beam dump and wasted, leading to reduced energy efficiency and reduced laser life. Second, micromirrors can only absorb some of the laser energy and handle only a limited amount of light output before they deform and fail. This limitation limits the printing speed and long-term reliability of the imaging system. Third, micro mirrors are mechanical parts that need to be carefully aligned with the rest of the optical system. Such mechanical switching components add complexity and cost.

  What is needed is a 1 watt scalable with over 20 '' wide processing width while having an achievable resolution greater than 1200 dpi and enabling high resolution high speed imaging in a single pass It is a laser based imaging approach with full light output much higher than the level.

The invention relates to a two-dimensional light field generator (e.g. one or more vertical cavity surface emitting laser (VCSEL) devices) for generating a two-dimensional modulated light field according to predetermined scan line image data; A single pass imaging system that utilizes anamorphic reduction optics to focus the modulated light field to form a narrow scan line image. Here, the term anamorphic optical system may be an optical lens, a mirror or other projection of light from an object plane, such as a pattern of light formed by a VCSEL device, onto the final image plane at different magnifications along orthogonal directions. Refers to any system of elements. Thus, for example, the square shaped imaging pattern formed by a 2D array of VCSEL laser elements is anamorphically projected to expand its width and at the same time reduce its height (or bring it into focus) Can form a square into a very thin elongated rectangular image in the final image plane. By utilizing anamorphic optics to focus the modulated light, scan line image without the need for a high intensity light source (ie, hundreds of orders of watt / cm ² ) of high total light intensity (flux density) Available reliable high-power imaging system requiring high energy laser lines in single pass high resolution high speed printing applications or industrial applications. Make it easy. Furthermore, one or more non-uniformities such that the light field generator provides substantially uniform light intensity across at least one dimension of the two-dimensional light field as directed by the predetermined scan line image data It should be clear that it can include multiple optical elements such as light pipes or microlens arrays that shape the light from various light sources.

  According to the aspect of the present invention, the light irradiation field generating device includes a plurality of light emitting elements (for example, light emitting diodes) arranged on the substrate in a two-dimensional array and a light generating structure (for example, laser diode) of each light emitting element But one or more second modulation states (e.g., portions) in which light having a relatively low intensity is generated. Control the light emitting elements individually according to predetermined scan line image data so that they can be adjusted between low intensity generated by the elements which are on (or zero intensity when the elements are completely off) And controller. If one of the light emitting elements is in a first modulation state or a partially modulated second modulation state, the light emitting elements direct a portion of the modulated light associated in the corresponding predetermined direction (e.g., elements in parallel) Transmit some of their associated light along anamorphic optics). By generating modulated light in this manner before being anamorphically projected and collected, the invention only applies a high power to one point of the scan line at any given moment. In contrast to the above, high power scan lines can be generated simultaneously along the entire imaging area. This approach also avoids the need for mechanical steering required for DLP based approaches. Furthermore, since the imaging system utilizes a portion of the relatively low power modulated light emitted from the plurality of light emitting elements, the present invention provides a low cost commercially available laser array device such as a commercially available VCSEL device. It can be manufactured using. Furthermore, by focusing a different number of light emitting elements at each pixel location, the imaging system may, for example, produce a high speed printing system (ie by focusing a relatively small number of modulated light portions) Higher to produce a lower intensity scan line or to produce a laser cutting system that can be useful in a wide range of industrial applications (ie by focusing a relatively large number of modulated light portions) An intensity scan line can be generated.

  According to another aspect of the invention, the array of light-emitting elements of the light-field generator is arranged in rows and columns, and the anamorphic optics system ) Are arranged so as to condense the light portions received from the respective rows above. That is, all of the light emitting elements in each column form an associated pixel group, and the collected modulated light portion received from each pixel group has the resulting imaged "pixels" in an "on" state (ie, The light is directed by anamorphic optics onto the same corresponding imaging area of the scan line image so that it is the combined light from all the light emitting elements of a given row that is fully on or partially on). An important aspect of the present invention is emitted by each light emitting element such that the brightness of each imaging "pixel" making up the scan line image is controlled by the number of elements in the associated column in the "on" state. It is understood that the light portion represents only a portion of one pixel of binary data supplied to the scan line by anamorphic optics. Therefore, by individually controlling a plurality of light emitting elements disposed in each row, and focusing the light passed by each row on the corresponding imaging region, the present invention provides the elements of each row An imaging system with gray scale capability is provided by controlling the number and / or degree (i.e. completely or partially) of the "on" modulation states of.

  According to another embodiment of the present invention, a two-dimensional light field generator includes a plurality of light generating / emitting elements (VCSEL laser elements) arranged in an array and collectively generating desired light energy 1 It is implemented using one or more vertical cavity surface emitting laser (VCSEL) devices. In other embodiments, the VCSEL device is either a single mode or a multi mode device. The light emitting elements of multi-mode VCSEL devices can have a larger aperture size than that of single mode devices and produce higher maximum light output. However, single mode devices have better beam quality. For the digital offset printing application of the present invention, the preferred embodiment is a multi-mode device.

  According to another embodiment, the VCSEL laser (light emitting) elements are handled using a common drive current generated independently or by a controller. Handling the light emitting elements independently involves generating and transmitting a separate control signal for each light emitting element, facilitating beam shaping but requiring many control lines and associated costs . In a presently preferred embodiment, the VCSEL device is fabricated such that the controller generates and transmits a plurality of drive currents, each drive current being associated with a pixel image data value, each drive current comprising all light emissions of a given column. It is supplied to the element. The use of a common (common) drive current for each column saves a lot of cost and complexity and gray scale control is further achieved by controlling the amount of current transferred to a given column in an analog manner Can. In another embodiment, parallel or series wiring is used to transfer the shared current to all the light emitting elements in each column. Generating a series wiring configuration requires more processing steps than parallel wiring, but allows higher voltage low current drive sources to be used.

  According to another alternative embodiment, improved optical throughput and collimation are achieved by placing a microlens on each light emitting element of the VCSEL array. In an alternative specific embodiment, the microlenses are arranged in an array on a substrate mounted in a hybrid manner on the VCSEL device (ie after the VCSEL elements have been manufactured), or the microlenses are It is monolithically integrated (ie, integrally disposed) on each VCSEL element as part of the array fabrication process. In either case, each microlens is arranged such that light generated by the associated VCSEL (light emitting) element passes through and is collimated by the associated microlens.

  According to yet another embodiment of the present invention, the light emitting elements of each column of VCSELs (light field generators) are in the cross-processed and processed vertical direction of the anamorphic optical system (ie, relative to the scan line image ) Aligned at a small oblique angle, this causes the anamorphic optics to focus each modulated light spot on the relevant sub-imaging area of the scanline image. The advantage of this parallelogram configuration (tilted orientation) is that the imaging system creates a spatially addressable space of higher sub-pixels and locates the image "pixels" with decimal precision in both the X and Y axis directions Provide an opportunity to use the software. The light emitting elements of the VCSEL (light field generating device) are optionally set to a tilt angle that produces an alignment of each imaging area by a plurality of elements arranged in different columns of the array, thereby varying the resolution and Make variable strength easy. This arrangement also facilitates software adjustment to stitch seamlessly between adjacent imaging subunits.

  According to another alternative embodiment, improved beam divergence characteristics in the line and cross line directions are achieved using different VCSEL element shapes, such as circular or rectangular. Those coupled to anamorphic cylindrical optics can optimize the collection of light to the pixel without loss of resolution.

  According to another embodiment of the present invention, the entire anamorphic optical system intersects to condense the modulated light portion received from the light field generator such that the collected modulated light forms a substantially one-dimensional scanning line image. The modulated optical light in the scan line image has a higher light intensity (i.e., higher flux density) than the homogenized light, including the optical subsystem of the process and the optical subsystem of the process direction. By anamorphically focusing the two-dimensional modulated light pattern to form a high energy elongated scan line, the imaging system of the present invention outputs a higher intensity scan line. The scan line is normally directed and swept across the movement of the imaging plane near its focal point. This allows the imaging system to be formed into a printer or the like. The direction of the surface sweep is usually perpendicular to the direction of the scan line and is commonly referred to as the process direction. Furthermore, the direction parallel to the scan line is commonly referred to as the cross process direction. The formed scanline image has different pairs of cylindrical or non-cylindrical lenses that address the convergence and tight focus of the scanline image along the process direction and the projection magnification of the scanline image along the cross process direction. Can. In one particular embodiment, the cross-processed optical subsystem comprises first and second cylindrical or non-cylindrical lenses arranged to project and expand modulated light onto the elongated scan line in the cross-process direction The optical subsystem in the processing direction includes a third cylindrical or non-cylindrical focusing lens arranged to collect and reduce modulated light on the scan line in a direction parallel to the processing direction. Including. This configuration produces a wide scan line that can be combined ("stitched" or blended with the area of overlap) with adjacent optics to produce an assembly having scan lines of substantially unlimited length. Make it easy to do. In one embodiment, aligned microlenses disposed on a light field generator are utilized to provide improved optical throughput. Alternatively, any collimated field lens may also be disposed between the light field generator and the cylindrical or non-cylindrical focus lens in both the process and cross process directions. The entire optical system may have several elements to help compensate for optical aberrations or distortions, such optical elements may be transmissive lenses or mirror lenses having multiple folds of the beam path It should be understood that it can be According to another embodiment of the present invention, various imaging systems and associated devices / systems include two-dimensional light field generators including a plurality of VCSEL devices arranged in an array. In an exemplary embodiment, a scanning / printing device includes a two-dimensional light field generator including a single row of VCSEL devices and associated elongated anamorphic optics arranged to produce elongated scan lines; A single pass imaging system having a scanning structure (e.g., an imaging drum cylinder) positioned to receive the collected modulated light from the optical system. By utilizing a sufficient number of VCSEL devices in a row, the imaging system is scalablely formed over a large processing width of over 20 ''. According to a particular embodiment, the imaging surface may hold a dampening (injection) solution such as that used for variable data lithographic printing. In another exemplary embodiment, two or more VCSEL devices are aligned in the process direction (ie, alignment of light emitting elements in which each column or associated pixel group is disposed on two or more VCSEL devices) To include the set). This arrangement facilitates producing a very high energy (ie, having a much higher light output than 1 watt level) laser line that can be useful in a wide range of industrial applications.

  These and other features, aspects and advantages of the present invention will be better understood with regard to the following description, appended claims and accompanying drawings.

FIG. 1 is a top perspective view of a simplified imaging system utilized in accordance with an exemplary embodiment of the present invention. FIG. 2 is a top perspective view of a partial imaging system utilizing individually addressed VSCEL laser diodes in accordance with a specific embodiment of the present invention. FIG. 2A is a schematic side view showing the imaging system of FIG. 2 during an imaging operation according to an embodiment of the present invention. FIG. 2 (B) is a schematic side view showing the imaging system of FIG. 2 during an imaging operation according to an embodiment of the present invention. FIG. 2C is a schematic side view showing the imaging system of FIG. 2 during an imaging operation according to an embodiment of the present invention. FIG. 3A is a simplified perspective view showing a partial imaging system utilizing a VSCEL laser diode controlled by a shared drive current according to an alternative embodiment of the present invention. FIG. 3B is a simplified perspective view of a partial imaging system utilizing a VSCEL laser diode controlled by a shared drive current according to an alternative embodiment of the present invention. FIG. 4A is a simplified top view illustrating the placement of microlenses utilized by the imaging system of FIG. 1 in accordance with another specific embodiment of the present invention. FIG. 4 (B) is a simplified side view illustrating the placement of microlenses utilized by the imaging system of FIG. 1 in accordance with another specific embodiment of the present invention. FIG. 5A is a VCSEL type light field generator having light emitting elements of various shapes and arranged in a parallelogram arrangement according to another embodiment of the present invention. FIG. 5B is a VCSEL type light field generator having light emitting elements of various shapes and arranged in a parallelogram arrangement according to another embodiment of the present invention. FIG. 6A is a plan view illustrating the layout of a simplified multi-lens anamorphic optical system utilized by the imaging system of FIG. 1 in accordance with another specific embodiment of the present invention. FIG. 6 (B) is a side view showing the layout of a simplified multi-lens anamorphic optical system utilized by the imaging system of FIG. 1 in accordance with another specific embodiment of the present invention. FIG. 7 is a simplified view showing the reduction characteristic of the anamorphic optical system of FIGS. 6 (A) and 6 (B). FIG. 8 is a simplified perspective view of an imaging system utilizing multiple VCSEL type light field generators according to another embodiment of the present invention. FIG. 9 is a perspective view of a printing system including an imaging system utilizing a VCSEL type light field generator in a folded configuration according to another particular embodiment of the present invention. FIG. 10A is a simplified side view of the imaging system of FIG. 9 during an imaging operation. FIG. 10 (B) is a simplified side view showing the imaging system of FIG. 9 during an imaging operation. FIG. 10C is a simplified side view of the imaging system of FIG. 9 during an imaging operation. FIG. 10 (D) is a simplified side view of the imaging system of FIG. 9 during an imaging operation. FIG. 11 is a perspective view of a high energy imaging system including a plurality of VCSEL devices arranged in an array according to another embodiment of the present invention.

  The present invention relates to improvements in imaging systems and related devices (eg, scanners and printers). The following description is presented to enable a person skilled in the art to make and use the present invention provided in the context of a particular application and its requirements. As used herein, directional terms such as "top", "top", "bottom", "vertical" and "horizontal" are intended to provide relative positions for purposes of illustration. It is intended and not intended to specify an absolute frame of reference. Various modifications to the preferred embodiment will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments. Thus, the present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

  FIG. 1 is a simplified single pass utilized to generate a substantially one-dimensional scanline image SL on a two-dimensional image on an imaging surface 162 in accordance with a simplified embodiment of the present invention. FIG. 1 is a perspective view showing an imaging system 100. The simplified imaging system 100 generally generates a two-dimensional light field generator that receives the image data ID from the system controller 180 and generates a two-dimensional modulated light field 119B according to the predetermined scan line image data ID. 120 and anamorphic optics 130 to image and focus the modulated light 118 B as described below to produce a scanline image SL on the imaging surface 162.

  The imaging process described herein includes processing digital image data corresponding to any two-dimensional image stored according to known techniques and referred to herein as an image data file ID. . The image data file ID is shown at the bottom of FIG. 1 and processes the image data file ID and writes the image data file ID one row at a time to the light field generator 120 as described below. It is transmitted to the controller 180 that transmits. That is, the image data file ID that matches most standardized image file formats consists of a plurality of scan line image data groups LID1 to LIDn, and each scan line image data group is associated with a one-dimensional scan associated with a two-dimensional image. It includes a plurality of pixel image data portions that collectively form line images. For example, in the simplified example shown in FIG. 1, scan line image data group LID1 includes four pixel image data portions PID1 to PID3. Each pixel image data portion (e.g., pixel image data portion PID1) is one or more bits of image data corresponding to color and / or grayscale characteristics of the corresponding pixel image associated with the corresponding portion of the two-dimensional image including. Those skilled in the art will recognize that in a practical embodiment, each scan line image data group includes a large number of pixel image data portions, such as the four, eight or twenty-four pixel image rows described herein. Will.

  Referring to FIG. 1, the two-dimensional light field generator 120 receives the received image data ID (eg, line image, etc.) to generate the associated modulated light portion 118B that collectively forms the two-dimensional modulated light field 119B. It includes an array 122 of light emitting elements 125 controlled by the device controller 126 according to the data group LID1). In the exemplary embodiment, the array 122 forms light that is modulated light field 119 B such that the modulated light field 119 B is projected through the anamorphic optics 130 onto the elongated imaging region 167 of the imaging surface 162. The light emitting devices 125-11 to 125-44 are arranged in a rectangular pattern that emits the portions 118B-11 to 118B-44, respectively. In a practical embodiment, the two-dimensional light field generator 120 includes an array 122 of multiple VCSEL (laser diode) elements. For the purpose of illustration, only a small subset of light emitting elements are shown in FIG. 1 and the various figures described herein.

  According to various alternative practical embodiments, the two-dimensional light field generator 120 includes one or more vertical cavity surface emitting laser (VCSEL) devices including a plurality of light generating / emitting elements (VCSEL laser elements) Is realized using. In alternative embodiments, the VCSEL device is either a single mode or multi mode device. The light emitting elements of multi-mode VCSEL devices can have a larger aperture size than that of single mode devices and produce higher maximum light output. However, single mode devices have better beam quality. For the digital offset printing application of the present invention, the preferred embodiment is a multi-mode device. In another alternative embodiment, the VCSEL device is either a top emitting or a bottom emitting device. The bottom emitting configuration is typically a flip chip mounted to a heat sink, so it has good thermal conductivity and can handle higher power operation than top emitting devices. However, the light needs to pass through the substrate, so the emission wavelength can not be shorter than the absorption band edge of the substrate material. In the case of a GaAs substrate, the wavelength is limited to longer than 870 nm. The substrate can be removed after flip chip bonding, but such processing adds cost and complexity. Although top emitting structures are simple to manufacture and package, they have reduced thermal properties. The presently preferred embodiment for digital offset printing applications is a VCSEL device having a bottom emitting flip chipped architecture and operating at a wavelength of 980 nm.

  Referring to the upper right area of FIG. 1, the modulation elements 125-11 to 125-44 are arranged on the semiconductor substrate (chip) 124 in four horizontal rows R1 to R4 and four vertical columns C1 to C4. The modulation elements 125-11 to 125-44 are arranged to direct their associated modulated light portions along a predetermined parallel path towards the anamorphic optics 130. Each light emitting element 125-11 to 125-44 is adjustable via control signal 127 generated by device controller 126 between two or more modulation states, the modulation state of each element being generated by that element Defined by the amount of light. For example, the array 122 is controlled in response to the line image data group LID1 as shown in FIG. 1, and the light emitting elements 125-11 are adjusted to a "full on" (first) modulation state, thereby The light emitting element 125-11 generates and transmits an associated modulated light portion 118B-11 having a maximum / maximum (first) intensity. Alternatively, if a given light emitting element is in a "partially on" or "off" (second) modulation state, then the given light emitting element transmits the associated light portion having a low (or zero) intensity. (Or not communicate). For example, light emitting element 125-21 is depicted as being in the "off" state, whereby the associated modulated light portion 118B-21 is black (i.e., does not include light). Alternatively, light emitting element 125-41 is depicted as being in the "partially on" state, so that the associated modulated light portion 118B-41 is higher than modulated light portion 118B-21, but modulated light It has a lower strength than the portion 118B-11. Thus, during the time the array 122 is controlled by the line image data group LID1, the elements 125-11 to 125-44 produce a two-dimensional light field 119B as depicted in FIG. The pattern of light and dark areas of field 119 B is a light emitting element adjusted to the second modulation state (eg, elements 125-21 to 125-24, 125-31 and 125-34 which are off, and partially on) Determined by the relative position of the light emitting elements (eg, elements 125-11 to 125-14, 125-32 and 125-33) to be adjusted to the first modulation state with respect to elements 125-41 to 125-44) . During a subsequent imaging phase (not shown), the second scanline image data portion is written to the control circuit 126 (i.e. the scanline image data portion LIN1 is overwritten) and the corresponding second scan Line images (not shown) are generated on other elongated imaging areas of the imaging surface 162. This processing requires the movement (translation) of the imaging surface 162 in the processing (Y axis) direction after the scanning line image SL is generated and before the second scanning line image is generated. Please keep in mind. Those skilled in the art will recognize that by repeating such an imaging step for each scanned image data portion LIN1 to LINn of the image data file ID, a related two-dimensional image is generated on the imaging surface 162. I will.

  Referring to the lower left portion of FIG. 1, the anamorphic optical system 130 functions to anamorphically focus (focus) the two-dimensional modulated light irradiation field 119B on the elongated imaging region 167 of the imaging surface 162. Do. In particular, the anamorphic optical system 130 includes one or more optical elements (e.g., lenses or mirrors) arranged to receive a two-dimensional pattern of the modulated light field 119B, e.g. The lens or mirror is arranged to focus the light received to a greater degree along the processing (eg Y-axis) direction than along the cross-processing (X-axis) direction, whereby the received light The sections are anamorphically focused to form an elongated scanline image SL extending parallel to the cross-process / scan (X-axis) direction. It should be noted that the modulated light portion that has passed through the anamorphic optical system 130 but has not yet reached the imaging plane 162 is referred to as a collected modulated light portion (e.g. And modulated light portion 118C-11 collected between the anamorphic optical system 130 and the imaging surface 162). The anamorphic system 130 is shown for simplicity in FIG. 1 by a single general anamorphic projection lens. In practice, the anamorphic system 130 is usually composed of a plurality of separate cylindrical or non-cylindrical lenses, as described below with reference to FIGS. 6 (A) and 6 (B). It is not limited to general lenses or the specific lens systems described herein.

  According to another aspect of the present invention, the anamorphic optical system 130 is configured to receive each row of light emitting elements 125-11 to 125-44 on the associated imaging area (imaging pixel) P1 to P4 of the elongated scanning line image SL It is arranged to collect the light part received (ie either fully on or partially on modulated state). As shown in FIG. 1, all four light emitting elements 125-11 to 125-14 of column C1 form a corresponding pixel group G1 and the associated generated by the light emitting elements 125-11 to 125-14. The modulated light portions 118B-11 to 118B-14 are condensed and guided by the anamorphic optical system 130 as the light portions 118C-11 to 118C-14 on the corresponding imaging area P1, and thereby, are focused on the imaging area P1. The resulting imaged pixels produced are the synthetically modulated light received from all the light emitting elements in column C1 which is fully on in this example, namely 125-11 to 125-14. Similarly, the light emitting elements 125-21 to 125-24 in column C2 form the associated pixel group G2, and the light emitting elements 125-31 to 125-34 in column C3 form the associated pixel group G3 and the column The light emitting elements 125-41 to 125-44 at C4 form the associated pixel group G4.

  An important aspect of the present invention is emitted by each light emitting element such that the brightness of each imaging "pixel" making up the scan line image is controlled by the number of elements of the associated row in the "on" state. It is understood that the light portion represents only a portion of one pixel of binary data supplied to the scan line by anamorphic optics. Therefore, according to the present invention, the device according to the present invention is configured by individually controlling a plurality of light emitting elements arranged in each row and condensing the light passing in each row over the corresponding imaging region. An imaging system having gray scale capability by controlling the number and / or degree (i.e. completely or partially) of the "on" modulation states of. As described above, since all of the elements 125-11 to 125-14 in the column C1 (group G1) are completely on, the imaging pixel P1 has the maximum luminance. Conversely, since all elements 125-21 to 125-24 are completely off in the depicted example, the associated modulated light portion is obtained in the imaging area P2 with minimum brightness (maximum darkness) To generate an imaged pixel. Grayscaling is achieved by the elements of column C3 (group G3) by adjusting elements 125-31 and 125-34 to fully off modulation states and adjusting elements 125-32 and 125-33 to fully on states, Thereby, the imaging pixels obtained in the imaging area P3 are generated only by the bright portions 118B-32 and 118B-33 and therefore have an intermediate luminance. Another way to achieve grayscaling is depicted by the elements of column C4 (group G4), all of the elements 125-41 and 125-44 being adjusted to a partial on modulation state, whereby The imaging pixels obtained in the imaging area P4 are produced by half-bright portions 118B-41 to 118B-44 and therefore have an intermediate luminance.

  According to the particular embodiments described with reference to FIGS. 2, 3A and 3B, various alternative two-dimensional light field generators may be operated independently or in common with the drive current. Containing light emitting elements that are treated using In particular, FIG. 2 shows a light field generator 120A in which the device controller 126A generates separate control signals for each light emitting element. As described below, handling the light emitting elements independently includes generating and transmitting a separate control signal for each light emitting element, facilitating beam shaping, but many control lines and Need related costs. In FIG. 3A and FIG. 3B, the light irradiation field generator 120B in which all the light emitting elements in each column (group) are controlled by a single (common) drive current (or voltage) And 120C. The use of shared (common) drive current for each column saves a lot of cost and complexity, and gray scale control is further achieved by controlling the amount of current transferred to a given column in an analog manner Can.

  Referring to FIG. 2, the imaging system 100A includes a two-dimensional light field generator 120A having an array 122A of light emitting elements 124-11 to 125-34 and a control unit 126A, and the control circuit 126A performs imaging It comprises an array of control (memory) cells 128-11 to 128-34 storing one scanline image data portion (e.g. scanline image data portion LIN1) during each imaging stage of the operation. For example, at a predetermined time, the scan line image data unit LIN1 is transmitted (written) from a system controller (not shown) to the device controller 126A using a known technique. In this example, device controller 126A interprets each associated pixel data value PID1-PID3 and generates a corresponding bit value that is subsequently written to control (memory) cells 128-11-128-34. For example, pixel data value PID1 is interpreted as a maximum intensity pixel value, so device controller 126A writes a logical "1" bit value to control cells 128-11 to 128-14. Similarly, pixel data value PID2 is interpreted as a minimum intensity pixel value, and PID3 is interpreted as a medium intensity pixel value, so that device controller 126A controls control cells 128-21 through 128-24, 128-31 and 128-34. Write a logical "0" bit value to and write logical "1" bit values to memory cells 128-32 and 128-33. As described below, each light emitting element 125-11 to 125-34 is associated to switch between a fully on (first) modulation state and a completely off (second) modulation state, respectively. Are individually controllable (e.g., via control signal 127A) via data bits stored in memory cells 128-11 to 128-34. By selectively controlling the light emitting elements 125-11 to 125-34 individually according to the image data ID as described above, the modulated light generator 120A generates the modulated light irradiation field 119B according to the supplied image data. Make it possible to generate.

  FIGS. 2A to 2C show singles of light emitting elements of the imaging system 100A (FIG. 2) after the above-mentioned bit values are written to the memory cells 128-11 to 128-34 of the control circuit 126A. FIG. 7 is a simplified side view showing a row, illustrating how each row (group) of light emitting elements is individually controlled to produce the modulated light field 119 B of FIG. 2; FIG. 2A shows the column C1 (group G1) of FIG. 2, and in particular, the memory cells 128-11 to 128-14 have the light focusing portions 118C-11 to 118C-14 the imaging plane, respectively. Each of the light emitting elements 125-11 to 125-14 focused anamorphicly by the anamorphic optical system 130A is turned on to generate the pixel P1 in the region SL1 on the 162 (for example, the light 118B to the light emitting element 125-11). 11, and emitting control signals 127A-11 to 127A-14 having values set according to the stored logical "1" data values. FIG. 2B shows column C2 (group G2) of FIG. 2, and in particular, the memory cells 128-11 to 128-14 turn off the light emitting elements 125-21 to 125-24, respectively. Control signals 127A-21 to 127A-24 having values set according to the determined logic "0" data value, whereby light does not pass through the anamorphic optical system 130A and It indicates that the pixel P2 in the region SL2 remains dark. FIG. 2C shows column C3 (group G3) of FIG. 2 in which control signals 127A-31 and 127A cause memory cells 128-31 and 128-34 to turn off light emitting elements 125-31 and 125-34. -34, and the memory cells 128-32 and 128-33 transmit control signals 127A-32 and 127A-33 to turn on the light emitting elements 125-32 and 125-33, respectively, whereby the light collecting portion 118C- is generated. Modulated light portions 118B-32 and 118B-33 to be anamorphically condensed by the anamorphic optical system 130A are generated so that the pixels 32 and 118C-33 generate the pixel P3 in the region SL3 on the imaging surface 162.

FIGS. 3A and 3B respectively include a two-dimensional light irradiation field generator having an array of light emitting elements 124-11 to 125-44, respectively, and associated pixel image data values of line image data LID. The imaging systems 100B and 100C respectively including associated control units configured to generate a shared drive current according to PID1 to PID4 are shown, said columns C1 to C4 forming associated pixel groups G1 to G4. All light emitting elements in C4 receive one of the shared drive current. The common drive of all the light emitting devices in a given row saves much expense and complexity in driving the light emitting devices, and the grayscale control controls the amount of current transferred to a given row in an analog manner Can be further achieved. For example, referring to FIG. 3A, the light field generator 120B includes an array 122B and a control unit 126B, and the control unit 126B is responsive to the associated pixel image data values PID1 to PID4, respectively, to drive current 127B. -1 to 127B-4, the array 122B is such that the elements 125-11 to 125-14 of column C1 (i.e. group G1) receive the drive current 127B-1 and the array C2 That is, elements 125-21 through 125-24 of group G2) receive drive current 127B-2 and elements 125-31 through 125-34 of column C3 (i.e., group G3) receive drive current 127B-3. Connected to controller 126B such that elements 125-41 to 125-44 of column C4 (i.e., group G4) receive drive current 127B-4. It has been. In the embodiment shown in FIG. 3 (A), gray scale control can be further achieved by controlling the amount of current transferred to a given column in an analog manner. For example, controller 126B is further illustrated by different shading of image pixels P1-P4 forming different shading and scan lines SL of corresponding modulated light portions 118B-11-118B-44 in modulated light field 119B. Maximum current is supplied to group G1, zero current is supplied to group G2, and two different intermediate currents are supplied to groups G3 and G4, each (eg, via a current control circuit indicated by a transistor) the generation method corresponding to the analog control value _C B1 _{-C B4} used to control the current applied to the pixel columns, each driven in accordance with the relevant pixel image data values PID1~PID4 current 127B-1~127B It is configured to change the analog value of -4. FIG. 3 (B), were similarly configured generate a driving current 127C-1~127B-4 in accordance with the pixel image data values PID1~PID4 associated respectively via an analog control value _C C1 _{-C C4} The second light field generator 120C including the control unit 126C is shown, wherein the elements 125-11 to 125-14 of the array 122C receive the drive current 127C-1 and the elements 125-21 to 125-24 are , Drive current 127C-2, elements 125-31 through 125-34 receive drive current 127C-3, and elements 125-41 through 125-44 receive drive current 127C-4. In the embodiment shown in FIGS. 3A and 3B, the light field generator 120B supplies drive currents 127B-1 to 127B-4 in parallel to their associated pixel groups. While the light irradiation field generation device 120C is configured to supply drive currents 127C-1 to 127C-4 in series (FIG. 3 (B)). It differs in the point)). The series arrangement of the light field generator 120C requires more steps but allows a higher voltage low current drive source to be used.

  Figures 4 (A) and 4 (B) illustrate a light field generator according to an alternative embodiment in which improved optical throughput and collimation are achieved by placing a microlens in front of each light emitting element It is a simplified diagram shown. FIG. 4A shows a light irradiation field generator 120D including a (first) substrate 121D on which the light emitting element 125D is formed, and a (second) substrate 140D including an array of microlenses 145D. In the substrate 140D, as shown by the bubbles on the right side of FIG. 4A, the light portion generated / transmitted by each light emitting element (eg, the light portion 118B-18 generated by the element 125D-18) is It is arranged in a hybrid fashion on substrate 121D during production to pass through the associated microlenses (e.g. microlenses 145D-18). Alternatively, FIG. 4B shows a microlens (eg, microlens 145E-18) to which the associated light portion (eg, light portion 118E-18) transmitted by each light emitting element (eg, device 125E-18) is associated. And the micro-lenses 145E are integrally disposed on the substrate 121E so as to pass through the light emitting field generator 120E. In any of the cases shown in FIGS. 4A and 4B, the use of microlenses was found to significantly improve the optical throughput (ie, the throughput ratio at the imaging plane is Measured to improve from 0.55 to 0.79).

  FIGS. 5A and 5B respectively show a light irradiation field generator 120F according to an alternative embodiment in which the light emitting elements in each row (ie, each pixel group) are arranged in a parallelogram configuration. It shows 120G. For example, FIG. 5A shows that the light emitting elements in each row / group (for example, the elements 125-11 to 125-13 in row C1 / group G1) are aligned at an oblique angle β with respect to the processing (Y axis) direction As shown, the light irradiation field generator 120F is shown in which the light emitting elements 125-11 to 125-43 are arranged in a parallelogram arrangement. By this arrangement, the collection modulated light portion is directed to the associated sub-imaging area of the elongated scan line image SL, and the sub-imaging area is slightly offset in the cross-process (X-axis) direction. For example, the elements 125-41 to 125-43 of the column C4 / group G4 are arranged in the manner described herein such that the light collectors 118C-41 to 118C-43 are led onto the pixel forming scan line image SL The modulated light portions 118B-41 to 118B-43 to be imaged and condensed by the anamorphic optical system 130F are emitted. Because the elements 125-41 to 125-43 are aligned along the oblique angle β, the modulated light portions 118B-41 to 118B-43 are slightly offset in the cross-process direction, thereby allowing the light collecting portion 118B- to 41-118B-43 are directed onto the associated sub-imaging areas SL-41 to SL-43 of the pixel image area P4 slightly offset from one another in the processing (Y-axis) and cross processing (X-axis) directions. By aligning the light emitters along an oblique angle β, the invention parallels (ie by utilizing software to position the image “pixels” with decimal accuracy in both the X and Y directions). It facilitates the formation of an imaging system that provides both the higher sub-pixel spacing associated with the quadrilateral arrangement and the superior pixel image generation provided by the multi-valued image exposure method. That is, the use of a parallelogram configuration similar to that shown in FIGS. 5 (A) and 5 (B) results in the summed emission from a given row being imaged relative to the scan line image SL It is possible to fill the pixel area. If the image of a single light emitting device is smaller than the pixel pitch, intensity modulation will occur along a line that is nominally perfectly strong (all pixels on). By adding together a slightly offset emission, it is possible to fill the complete imaged pixel.

  According to another aspect of the alternative exemplary embodiments shown in FIGS. 5A and 5B, the improved beam divergence characteristics in the processing and cross-processing directions can be used as image pixels without loss of resolution. This can be achieved by adjusting the shape of the light emitting element so as to optimize the concentration of light. For example, the light emitting element 125F (FIG. 5A) of the light irradiation field generator 120F has a rectangular shape that generates a specific beam divergence. In some cases, as shown by light field generator 120G in FIG. 5 (B), the improved beam divergence characteristics in the processing and cross-processing direction may be by forming a light emitting element 125G having a circular or elliptical shape. It can be achieved.

  6A and 6B are simplified diagrams illustrating portions of an imaging system 100H including generic anamorphic optics 130H in accordance with an exemplary embodiment of the present invention. Referring to FIG. 6 (A), the anamorphic optical system 130H comprises an optional collimating optical subsystem 131H, a cross processing direction optical subsystem 133H, and a processing direction optical optical according to an exemplary embodiment of the present invention. And subsystem 137H. As shown by the light ray traces in FIGS. 6A and 6B, the optical subsystems 131H, 133H and 137H are scan lines SL generated at the output of the light field generator 120H and the imaging system 100H. In the light path between FIG. 6A shows collimated optics of the modulated light portion 118B passed by the light irradiation field generator 120H to form the light collecting portion 118C on the scanning line SL parallel to the X axis (that is, the cross processing direction). FIG. 6B is a plan view showing that the subsystem 131H and the cross processing direction optical subsystem 133H act, and in FIG. 6B, the collimating optical subsystem 131H and the process direction optical subsystem 137H operate on the modulated light portion 118B; FIG. 18 is a side view showing a method of generating the light collecting unit 118C on the scanning line SL in the direction orthogonal to the Y axis (that is, the processing direction). The optional collimating optical subsystem 131H is located immediately after the spatial light modulator 120H and is arranged to collimate the light slightly diverged from the surface of the spatial light modulator 120H according to known techniques. It includes a formed collimating field lens 132H. Cross-processing directional optical subsystem 133H is a two-lens cylindrical or non-cylindrical projection system that magnifies light in the cross-processing (scan) direction (ie, along the X-axis); A cylindrical or non-cylindrical single focus lens system that focuses light in the process (cross-scan) direction (ie, along the Y axis). An advantage of this arrangement is that it enables the intensity of the light (e.g. laser) output focused on scan line SL located at the output of single pass imaging system 100H. A bi-lens cylindrical or non-cylindrical projection system 133H projects the modulated light portion (imaging data) 118B passed by the light field generator 120H onto an imaging plane (eg, a cylinder) in the cross-process direction And includes a first cylindrical or non-cylindrical lens 134H and a second cylindrical or non-cylindrical lens 136H (and optional collimating optics subsystem 131H) arranged to expand. The lens subsystem 137H includes a third cylindrical or non-cylindrical lens 138H that collects imaging data projected to a narrow high resolution line image on scan line SL. Since the focusing power of the lens 138H is increased, the light intensity on the spatial light modulator 120H is reduced as compared to the intensity of the line image generated on the scanning line SL. However, this means that a cylindrical or non-cylindrical lens 138H must be placed near the processing surface (eg, imaging drum) with a clear aperture extending to the very edge of the lens 138H.

  According to this preferred embodiment, the anamorphic optical system 130H processes less than 1 (reduction), depending on the desired line width and the cross process direction optical power selected to provide the desired line length. Formed with directional optical power. In a practical embodiment, the anamorphic optics 130H are manufactured with a magnification of −1.96 in the cross-process direction and −0.14 in the process direction. Multimode VCSELs will require higher numerical aperture projection optics for a given resolution. This may limit the amount of reduction in optical resolution or processing direction. The imaging quality may also be inferior but may be acceptable depending on the particular application.

  FIG. 7 illustrates the concept of using reduction optics to combine the integrated light output of a VCSEL array onto a collected spot. Thus, the enhanced light output provided by the plurality of VCSELs can be provided to small pixels. A plurality of pixels can then be placed on the line by each pixel being addressed by turning on or off the corresponding set of VCSEL elements. The example of FIG. 7 illustrates the concept using a two-lens spherical optical system consisting of an F1 = 20 mm lens and an F2 = 3 mm lens separated by 15 mm. By arranging the VCSEL array at a distance d01 = 3 mm from the first lens, a 5 × reduction is achieved at the image plane di2. In the example using a 217 μm × 108 μm 32-element VCSEL array, an experiment using the optical system described in FIG. 5 produces an image reduced by 5 times to a suitable 42 μm × 21 μm pixel for a 600 dpi line generator. did. Although this display system images a two-dimensional VCSEL array to form pixels, the same concept applies to pixels with cylindrical anamorphic optics that can be scaled down in the column direction and expanded in the row direction. It applies to the actual situation in which it is formed.

  According to various practical embodiments, the imaging system produced according to the invention comprises a two-dimensional light field generator comprising a plurality of VCSEL devices arranged in an n × m array, n and m Is an integer, and at least one of n and m is more than one. FIG. 8 shows a VCSEL device 120J-1 in which the two-dimensional light irradiation field generator 120J is aligned in the cross process (X-axis) direction with the VCSEL devices 120J-1 to 120J-3 arranged in a 1 × 3 array. , 120J-2 and 120J-3. By operating the VCSEL device in the manner described above (ie by imaging and concentrating the modulated light portion 118B generated by the light emitting elements 125J in each column to generate a line of pixel images), and appropriately By providing a wide anamorphic optical system, this device facilitates generating a longer scan line image SL than can be achieved using a single VCSEL device, and The length can be easily made longer by increasing the number of VCSEL devices aligned (and making appropriate changes to the optics). The basic idea is to form a long chain of VCSEL devices and map the collimated output of a row of light emitting devices onto a single pixel in the imaging plane, as described below Facilitate various devices / systems such as scanning / printing devices.

  FIG. 9 illustrates a two-dimensional light field generator 120M including a single row of VCSEL devices configured as described above with reference to FIG. 8 and generating elongated scan lines according to another particular embodiment of the present invention FIG. 10A is a perspective view showing a scanning / printing apparatus 400M including a single pass imaging system 100M with associated elongated anamorphic optics 130M positioned to: The imaging system 100M also includes a controller that transmits a scanline image data portion (eg, partial LIN 11) to each VCSEL device of the light field generator 120M. Similar to the embodiment of FIG. 8, the light irradiation field generator 120M is a modulated light irradiation field 119B imaged and collected by the cross processing direction optical subsystem 133M of the anamorphic optical system 130M and the processing direction optical subsystem 137M. Is generated on the outer (imaging) surface 162M, which in this case is realized by the drum cylinder 160M. In this embodiment, the anamorphic optical system 130M is effectively "reversed" the position and the order from left to right of the two scan line images generated on the drum cylinder 160M in both the process and cross process directions. As such, the modulated light field 119B is reversed in both the process and cross process directions. Consistent with the above-described aspects, multi-level image exposure activates adjacent light emitting elements disposed in the central region of the MEMS mirror feature group to which the gray scale pixel image is associated, or an analog drive current in the manner described above. Use imaging system 100M by configuring groups of light emitting elements of a VCSEL device to form light field generator 120M substantially aligned in the process (Y-axis) direction as realized by utilizing To be achieved.

  10A-10D are simplified side views illustrating the scanning / printing device 400M of FIG. 9 during an exemplary imaging operation. It should be noted that the simplified side view ignores the inversion in the process direction so that the anamorphic optics 130M are depicted by a single cross-processed lens.

  FIG. 10A shows an imaging system in which the exemplary modulation element group G2 of the spatial light modulator 120M is configured in accordance with the scanning line image data group PID12 in the manner described above with reference to FIG. 100M (T1) (i.e. the imaging system 100M during the first period T1 of the imaging operation) is shown. In particular, FIG. 10A shows pixel image data such that elements 125M-22 to 125M-27 are activated (full on) and elements 125M-21 and 125M-28 are inactive (full off). The structure of the light emitting element 125M-21-125M-28 which used part PID12 is shown.

  Referring to the right side of FIG. 10A, in order to realize the image transfer operation, the imaging system 100M further supplies a dampening solution 192 to the imaging surface 162M at a point upstream of the imaging area. A source 190 and an ink supply 195 for applying ink material 197 at a point downstream of the imaging area. In addition, a transport mechanism (not shown) is provided to transfer the ink material 197 to the target print media, and a cleaning mechanism 198 is provided to prepare the imaging surface 162M for the next exposure cycle. The image transfer operation is further described below with reference to FIGS. 10 (B) -10 (D).

  Referring again to FIG. 10A, because of their modulation (on / off) state, the light emitting elements 125M-22 to 125M-27 form the modulated light irradiation field 119B guided through the anamorphic optical system 130M. Modulation light portions 118B-21 to 118B-27. The anamorphic optical system 130M forms a pixel image P12 which forms a part of the scanning line image SL1 in the elongated surface region 162M-1 on the imaging surface 162M by imaging and condensing the modulated light irradiation field 119B. To generate a focused modulated light irradiation field 119C. In particular, the associated collected light formed by the modulated light portions 118B-21 to 118B-27 is elongated surface area 162M-1 (ie, so that surface area 162M-1 in pixel image P21 is exposed). The dampening solution 192 is removed (evaporated). It should be noted that the size of the pixel image P21 (ie the amount of dampening solution removed from the imaging surface 162M) is determined by the number of activated light emitting elements.

  10 (B), 10 (C) and 10 (D) show the imaging system 100M at the time point following time T1, and the spatial light modulator 120M has the surface feature P12 (FIG. 10 (A)). ) Are deactivated for the method to be used later in response to the image transfer operation of the imaging system 100M. Referring to FIG. 10B, at time T2, the drum cylinder 160M rotates such that the surface area 162M-1 passes below the ink supply source 195. Due to the removal of the dampening solution shown in FIG. 10A, the ink material 197 adheres to the exposed surface area 162M-1 to form the ink features TF. Referring to FIG. 10C, weak adhesion between the ink material and the surface area 162M-1 and the printing medium (not shown) while the ink feature TF passes through the transfer point at time T3. The strong attraction of the ink material results in the transfer of the ink features TF to the print medium, resulting in "dots" of ink printed on the print medium. At subsequent T4, as shown in FIG. 10D, surface area 162M-1 is an optional residual ink and dampening solution material to prepare surface area 162M-1 for later exposure / printing cycles. Below the cleaning mechanism 198 to remove the According to the image transfer operation described above, the ink material is transferred onto only a portion of the imaging surface 162M exposed by the imaging process described above (ie, the ink material does not adhere to the dampening solution 192), Thus, the ink material is only transferred to the print medium from the portion of drum roller 160H that is exposed to light collection as described herein. Therefore, instead of fixed data from the plate as in conventional systems, variable data from which the dampening solution has been removed is transferred. For this process, a single very high power light source (e.g., a laser) operates the dampening solution in real time so that it operates using a raster light source (i.e., a light source rastered across the scan line) It will be needed to get rid of enough. An advantage of the imaging operation of the present invention is that because the liquid is simultaneously removed from the entire scan line, the configuration of the offset press can be provided at high speed using multiple relatively low power light sources. .

FIG. 11 illustrates an imaging system 100N according to another exemplary embodiment including six VCSEL devices 120N-1 through 120N-6 in which a two-dimensional light field generator 120N is arranged in a 2 × 3 array. The VCSEL devices 120N-1, 120N-2 and 120N-3 form the upper row, and the VCSEL devices 120N-4, 120N-5 and 120N-6 form the lower row. In this configuration, two or more VCSEL devices are processed such that each column (ie, each associated pixel group) includes an aligned set of light emitting elements disposed on the two or more VCSEL devices (Y Aligned in the axis) direction. For example, as shown by the bubbles on the right side of FIG. 11, the column C21 of the light irradiation field generation device 120N includes the light emitting elements 125-181 to 125-187 of the VCSEL device 120N-1 and the light emitting elements of the VCSEL device 120N-4. A pixel group G21 including 125-481 to 125-487 is provided. As shown in the left side of FIG. 11, since the anamorphic optical system 130N images and condenses all the light from the pixel group G21 on a single image pixel area P21, this configuration is Fig. 6 illustrates a method that can be utilized to facilitate the generation of very high energy laser lines that the invention can be useful in a wide range of industrial applications.

Claims (8)

In a single pass imaging system
A plurality of light emitting elements arranged in a two-dimensional array, wherein each light emitting element transmits an associated modulated light portion having a first intensity when each light emitting element is in a first modulation state; Each light emitting element transmits the associated light portion having a second intensity lower than the first intensity when each light emitting element is in the second modulation state, and each light emitting element corresponds to a predetermined direction Each light emitting element being adjusted between two or more modulation states such that the plurality of light emitting elements are modulated to generate a modulated two-dimensional light field. Said plurality of light emitting elements being possible;
A two-dimensional light irradiation field generator including a controller configured to control the plurality of light emitting elements according to the received image data;
The light emitting device is disposed to receive the modulated two-dimensional light irradiation field from the two-dimensional light irradiation field generator, and transmitted from the respective light emitting elements such that the collected modulated light beam part generates an elongated scanning line image And anamorphic optics arranged to collect the associated light portion.
The plurality of light emitting elements are arranged in a plurality of rows and a plurality of columns, all of the light emitting elements in each of the columns forming an associated pixel group;
Said anamorphic optical system is arranged to focus the modulated light portion received from each associated pixel group of said plurality of light emitting elements onto said associated scan line portion of said elongated scan line image;
The anamorphic optical system includes a cross processing optical subsystem and a process direction optical subsystem,
The cross processing optical subsystem includes first and second focus lenses arranged to project and magnify the modulated light portion only in the cross processing direction,
The processing direction optical subsystem includes a third focusing lens arranged to focus the modulated light portion on the elongated scan line image parallel to the processing direction;
An imaging system , wherein each of the first, second and third focus lenses comprises a cylindrical lens and a non-cylindrical lens .   The imaging system according to claim 1, wherein said anamorphic optical system further comprises a collimating lens disposed between said two-dimensional light field generator and a plurality of said focusing lenses.   The imaging system of claim 1, wherein the two-dimensional light field generator comprises a plurality of vertical cavity surface emitting laser (VCSEL) devices arranged in an array.   4. The imaging system of claim 3, wherein each of the associated groups of pixels comprises the set of light emitting elements disposed on two or more VCSEL devices.   In a single pass imaging system
  A plurality of light emitting elements arranged in a two-dimensional array, wherein each light emitting element transmits an associated modulated light portion having a first intensity when each light emitting element is in a first modulation state; Each light emitting element transmits the associated light portion having a second intensity lower than the first intensity when each light emitting element is in the second modulation state, and each light emitting element corresponds to a predetermined direction Each light emitting element being adjusted between two or more modulation states such that the plurality of light emitting elements are modulated to generate a modulated two-dimensional light field. Said plurality of light emitting elements being possible;
  A controller configured to control the plurality of light emitting elements according to received image data;
A two-dimensional light field generator including:
  The light emitting device is disposed to receive the modulated two-dimensional light irradiation field from the two-dimensional light irradiation field generator, and transmitted from the respective light emitting elements such that the collected modulated light beam part generates an elongated scanning line image. And anamorphic optics arranged to collect the associated light portion.
  The anamorphic optical system includes a cross processing optical subsystem and a process direction optical subsystem,
  The cross processing optical subsystem includes first and second focus lenses arranged to project and magnify the modulated light portion only in the cross processing direction,
  The processing direction optical subsystem includes a third focusing lens arranged to focus the modulated light portion on the elongated scan line image parallel to the processing direction;
  An imaging system, wherein each of the first, second and third focus lenses comprises a cylindrical lens and a non-cylindrical lens.   6. The imaging system of claim 5, wherein the two-dimensional light field generator comprises at least one of a multimode vertical cavity surface emitting laser (VCSEL) device and a single mode VCSEL device.   The controller is configured to generate a plurality of drive currents, each drive current corresponding to an associated pixel image data value;
  7. The imaging system of claim 6, wherein all of the light emitting elements of each row forming the associated pixel group receive the associated drive current transmitted from the controller to all of the light emitting elements.   6. The imaging system of claim 5, wherein the anamorphic optical system further comprises a collimating lens disposed between the two-dimensional light field generator and the plurality of focus lenses.