JP2006030986A - Image drawing apparatus and image drawing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease uneven resolution and density caused by errors of an installation angle of a drawing head and by influences of pattern distortion in an image drawing apparatus and an image drawing method for multiple overlay drawing. <P>SOLUTION: A drawing head 30 having a pixel array having a large number of usable pixels two-dimensionally arranged is presented, wherein the direction of pixel columns of the usable pixels and the scanning direction of the drawing head 30 make a specified predetermined inclination angle. Active pixels to be used for N-overlay drawing in the great number of usable pixels are specified to operate by an active pixel specification means comprising an active pixel designating part 140, a setting changing means 150 and so on. Then the pixels designated to be used by the above setting are operated to draw an image on a drawing surface while relatively moving the exposure head 30 against a stage 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a drawing apparatus and a drawing method, and more particularly to a drawing apparatus and a drawing method for forming a two-dimensional pattern represented by image data on a drawing surface by multiple drawing.

  2. Description of the Related Art Conventionally, various drawing apparatuses that include a drawing head and that form a desired two-dimensional pattern represented by image data on a drawing surface by the drawing head are known. A typical example is an exposure apparatus that forms a desired two-dimensional pattern on an exposure surface of a photosensitive material or the like by an exposure head for producing a semiconductor substrate or a printing plate. In general, an exposure head of such an exposure apparatus includes a pixel array such as a light source array or a spatial light modulator that generates a light spot group having a large number of pixels and forming a desired two-dimensional pattern. By operating the exposure head while moving it relative to the exposure surface, a desired two-dimensional pattern can be formed on the exposure surface.

  In particular, in recent years, in order to improve resolution, an exposure head having a pixel array in which pixels are arranged two-dimensionally, a scanning line of light from each pixel is replaced with a scanning line of light from another pixel. Several exposure apparatuses of the type that are used so as to match and expose each point on the exposure surface by substantially overlapping a plurality of times have begun to be proposed.

  For example, in Patent Document 1, in order to improve the resolution of a two-dimensional pattern formed on an exposure surface and to express a pattern including a smooth diagonal line, a plurality of micromirrors are two-dimensionally formed. An exposure apparatus using a rectangular digital micromirror device (DMD) arranged in an inclined manner with respect to the scanning direction so that exposure spots from adjacent micromirrors partially overlap on the exposure surface is described. Has been.

  Further, Patent Document 2 also uses a rectangular DMD that is inclined with respect to the scanning direction to express a color image by overlapping exposure spots on the exposure surface and changing the total illumination chromaticity. An exposure apparatus that can suppress an imaging error due to a factor such as a partial defect of a microlens provided corresponding to each pixel of the DMD is described.

Further, Patent Document 3 also uses a rectangular DMD that is tilted with respect to the scanning direction, so that the influence of variations in the amount of light from each micromirror is leveled, and the two-dimensional formed on the exposure surface. An exposure apparatus that can reduce pattern density unevenness is described.
US Pat. No. 6,493,867 Special table 2001-500628 gazette Japanese Patent Laid-Open No. 2004-9595

  However, when multiple exposure is performed using a pixel array in which pixels are arranged two-dimensionally with the pixel column inclined with respect to the scanning direction, it is generally difficult to finely adjust the mounting angle of the exposure head including the pixel array. In many cases, the inclination angle of the pixel row with respect to the scanning direction slightly deviates from the ideal setting inclination angle. If there is such a deviation, the density and arrangement of the exposure spots in other parts of the exposure surface will be exposed at locations on the exposure surface exposed by light rays from some pixels near the edge of each pixel row. Therefore, the resolution and density of the formed two-dimensional pattern become uneven.

  In addition to the above-described displacement of the mounting angle, a two-dimensional pattern in which pattern distortion generated on the exposure surface due to various aberrations of the optical system between the pixel array and the exposure surface, distortion of the pixel array itself, and the like is also formed. Cause unevenness in resolution and density.

  One way to eliminate these irregularities is to improve the adjustment accuracy of the mounting angle of the exposure head, the pixel placement accuracy, the optical system adjustment accuracy, and the like. The cost will be very high.

  The same problem may occur not only in the exposure apparatus but also in other types of drawing apparatuses such as an ink jet printer having an ink jet recording head that performs drawing by discharging ink droplets toward a drawing surface.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a drawing apparatus and a drawing method in a multiple drawing format in which unevenness in resolution and density due to the influence of a mounting head error and pattern distortion is reduced. is there.

  That is, the drawing apparatus according to the present invention is a drawing apparatus that draws a drawing surface by N-fold drawing (N is a natural number of 2 or more) and forms a two-dimensional pattern represented by image data on the drawing surface. One or a plurality of drawing heads having a pixel array that has a number of usable pixels arranged in a dimension and generates a drawing point group constituting the two-dimensional pattern according to the image data. The drawing head attached to the drawing surface so that the pixel column direction of the usable pixels and the scanning direction of the drawing head form a predetermined inclination angle, Moving means for relatively moving the drawing head in the scanning direction, and use pixel setting for setting each of the drawing heads so that the use pixel used for N-fold drawing among the many usable pixels is actually operated. hand That it comprises a and is characterized in.

  The used pixel setting unit may set the used pixel based on an actual inclination angle formed by an actual pixel column direction on the drawing surface indicated by the drawing point group and the scanning direction. The used pixel setting unit may include a used pixel specifying unit that specifies a used pixel and a setting changing unit that changes a setting so that only the used pixel actually operates.

  Here, in the present invention, the “pixel column” refers to an arrangement in a direction in which the angle formed with the scanning direction is smaller among the two arrangement directions of the pixels arranged two-dimensionally on the pixel array. “Pixel row” refers to an array in a direction having a larger angle with the scanning direction. Note that the arrangement of the pixels on the pixel array is not necessarily a rectangular grid, and may be, for example, an arrangement of parallelograms.

  Further, in the present invention, “N-fold drawing” means that in almost all the drawing area on the drawing surface, a straight line parallel to the scanning direction is a pixel row of N used pixels projected on the drawing surface. It refers to drawing processing with settings that intersect. Here, “substantially all areas” of the drawing area is described as the pixel columns of the used pixels intersecting with the straight line parallel to the scanning direction by tilting the pixel columns at both side edges of each pixel array. In this case, even if it is used to connect a plurality of drawing heads, the number of pixel columns of the used pixels that intersect with the straight line parallel to the scanning direction is small due to errors such as the drawing head mounting angle and arrangement. In addition, in a very small part below the resolution of the connection between the pixel columns of each used pixel, the direction along the direction orthogonal to the scanning direction is due to errors such as the mounting angle and pixel arrangement. This is because the pixel pitch does not exactly match the pixel pitch of other portions, and the number of pixel columns of used pixels that intersect with a straight line parallel to the scanning direction may increase or decrease within a range of ± 1.

  On the other hand, in ideal N-fold drawing, a straight line parallel to the scanning direction intersects with a pixel row of N used pixels projected on the drawing surface in all areas of the drawing area on the drawing surface. This refers to drawing processing with such settings.

  In the following description, N-fold drawing in which N is a natural number of 2 or more is collectively referred to as “multiple drawing”. Further, in the following description, “N double exposure” and “multiple drawing” are used as terms corresponding to “N double drawing” and “multiple drawing” for an embodiment in which the drawing apparatus or drawing method of the present invention is implemented as an exposure apparatus or exposure method. The term “multiple exposure” shall be used.

  Further, the “used pixel designation means” in the present invention may accept manual designation of used pixels, and includes a position detection means, selection means, etc., which will be described later, and automatically selects the optimum used pixels. You may do.

  In addition, in the above description, “change the setting so that only the used pixels are actually operated” means, for example, a mode in which pixels other than the used pixels among the usable pixels are set to be off, or the image data is used. The portion sent to the pixels other than the pixels may be in the form of off-state data (that is, data indicating that drawing is not performed), and usable pixels other than the used pixels are also operated. It may be a form in which shielding or the like is performed so that a drawing medium such as a light beam or an ink jet does not reach the drawing surface.

Further, in the above drawing apparatus according to the present invention, the set inclination angle θ includes the number s of pixels forming each pixel column of the usable pixels, the pixel pitch p in the pixel column direction of the usable pixels, and For the pixel column pitch δ of those usable pixels along the direction orthogonal to the scanning direction,

It is preferable that the angle satisfies the above relationship.

  In the drawing apparatus according to the present invention, the use pixel specifying unit may specify the use pixel in units of pixel rows.

  Further, the use pixel specifying unit specifies an actual inclination angle formed by the actual pixel row direction on the drawing surface indicated by the drawing point group and the scanning direction, and the actual inclination angle and the set inclination angle are set. The used pixels may be designated in units of pixel rows so as to absorb the error between them. In that case, the use pixel specifying means described above uses a plurality of columns of drawing points on the drawing surface corresponding to a plurality of pixel columns of usable pixels as a representative drawing point sequence, and the plurality of representative drawing point sequences. For each, an individual actual inclination angle formed by the direction of the representative drawing point sequence and the scanning direction may be specified, and a representative value of the individual inclination angles may be set as the actual inclination angle. Here, as the “representative value of the individual inclination angle”, for example, any one of an average value, a median value, a maximum value, and a minimum value of all the specified individual inclination angles can be used.

  Further, the pixel array of each of the drawing heads may generate a light spot group as the drawing point group.

  In the drawing apparatus according to the present invention, the pixel array of each drawing head generates a light point group as the drawing point group, and the use pixel designation unit includes each drawing head. The position detection means for detecting the position of the light spot constituting the light spot group on the drawing surface, and for each drawing head, on the drawing surface based on the detection result by the position detection means, In a representative region including at least one drawing portion by a connecting portion between pixel columns of used pixels, a portion where drawing is redundant with respect to ideal N-fold drawing and drawing is insufficient with respect to ideal N-fold drawing A selection means for identifying unused pixels in the usable pixels so that the total of the portions becomes the minimum, and selecting pixels excluding those unused pixels as the used pixels It may be.

  Alternatively, the pixel array of each drawing head generates a light point group as the drawing point group, and the use pixel designating unit includes the light constituting the light point group for each drawing head. Position detection means for detecting the position of the point on the drawing surface, and drawing for each drawing head based on the result of detection by the position detection means on the drawing surface by the connecting portion between the pixel columns of the used pixels. In the representative area including at least one location, the number of drawing points in a portion where drawing is redundant for ideal N-fold drawing and the number of drawing points in a portion where drawing is insufficient for ideal N-fold drawing are It may be provided with selection means for specifying unused pixels among the usable pixels so as to be equal, and selecting pixels excluding those unused pixels as the used pixels.

  Alternatively, the pixel array of each drawing head generates a light point group as the drawing point group, and the use pixel designating unit includes the light constituting the light point group for each drawing head. Position detection means for detecting the position of the point on the drawing surface, and drawing for each drawing head based on the result of detection by the position detection means on the drawing surface by the connecting portion between the pixel columns of the used pixels. In the representative area including at least one location, the portion where the drawing is redundant with respect to the ideal N-fold drawing is minimized, and the portion where the drawing is insufficient with respect to the ideal N-fold drawing does not occur. In addition, it may be provided with a selection means for specifying unused pixels in the usable pixels and selecting pixels excluding those unused pixels as the used pixels.

  Alternatively, the pixel array of each drawing head generates a light point group as the drawing point group, and the use pixel designating unit includes the light constituting the light point group for each drawing head. Position detection means for detecting the position of the point on the drawing surface, and for each drawing head, based on the detection result by the position detection means, the connection portion between the pixel columns of the used pixels on the drawing surface In the representative area including at least one drawing portion, the portion where drawing is insufficient for the ideal N-fold drawing is minimized, and the portion where drawing is redundant for the ideal N-fold drawing does not occur. As described above, it may be provided with selection means for specifying unused pixels in the usable pixels and selecting pixels excluding those unused pixels as the used pixels.

  Further, the drawing device according to the present invention may specify the unused pixels in units of pixel rows.

  Furthermore, in the above-described drawing apparatus according to the present invention, the selecting unit projects onto the drawing surface indicated by the light spot group based on the detection result of the position of at least two light spots by the position detecting unit. The actual inclination angle formed by the actual pixel row direction and the scanning direction described above may be specified, and the unused pixels may be specified based on the actual inclination angle. In that case, the selection means sets one column of light spots on the drawing surface corresponding to one of the pixel columns of the usable pixels as a representative light spot column, the representative light spot column and the The actual inclination angle may be specified based on the detection result by the position detection unit of the position of at least two light spots among the light spots forming the adjacent light spot array. Here, it is preferable to select a light spot row near the center as the one representative light spot row. Alternatively, the selection unit may use a plurality of columns of light spots on the drawing surface corresponding to a plurality of the pixel columns of the usable pixels as a representative light spot row, and each of the plurality of representative light spot rows. Based on the detection result of the position detecting means of the position of at least two light spots among the light spots forming the representative light spot train and the light spot train in the vicinity thereof, the direction of the representative light spot train and the above-mentioned The individual actual inclination angles formed by the scanning direction may be specified, and the representative values of the individual inclination angles may be set as the actual inclination angles. Here, as the “representative value of the individual inclination angle”, for example, any one of an average value, a median value, a maximum value, and a minimum value of all the measured individual inclination angles can be used.

  In the drawing apparatus according to the present invention, the use pixel designating unit designates the use pixel, and therefore, for each drawing head, among the many usable pixels, the N is used. (N-1) The apparatus may further include reference drawing means for performing reference drawing using only pixels constituting every other pixel row.

  Alternatively, in the drawing apparatus according to the present invention, the use pixel designating unit designates the use pixel, and therefore, for each drawing head, among the many usable pixels, the N is used. And a reference drawing means for performing reference drawing using only pixels constituting a group of adjacent pixel rows corresponding to 1 / N of the total number of usable pixel rows. May be. Here, when the total number of usable pixel rows is not divisible by N, the above-mentioned “group of adjacent pixel rows corresponding to 1 / N of the total number of usable pixel rows” A group consisting of the number of pixels closest to 1 / N of the total number of pixel rows, the maximum number of 1 / N or less of the total number of pixel rows, or the minimum number of pixel rows of 1 / N or more of the total number of pixel rows Etc. may be selected.

  In addition, the drawing apparatus according to the present invention described above stores the image data so that the size of the predetermined portion of the two-dimensional pattern represented by the image data matches the size of the corresponding portion that can be realized by the designated use pixel. Data conversion means for converting may be further provided.

  Furthermore, in the drawing apparatus according to the present invention, the pixel array may be a spatial light modulation element that modulates light from a light source for each pixel according to the image data. Here, the above-mentioned “light source” may be incorporated in each drawing head (exposure head), or for each drawing head or a plurality of drawing provided outside each drawing head. It may be a light source shared between the heads.

  In the drawing apparatus according to the present invention, the number N of N multiple exposures is preferably a natural number of 3 or more and 7 or less.

  A drawing method according to the present invention includes a pixel array having a number of usable pixels arranged two-dimensionally and generating a drawing point group constituting a two-dimensional pattern represented by the image data according to the image data. One or a plurality of drawing heads, wherein the drawing heads attached to the drawing surface are arranged such that the pixel row direction of the usable pixels and the scanning direction of the drawing head form a predetermined inclination angle. In the drawing method used, for each drawing head, setting is performed such that a use pixel used for N-fold drawing (N is a natural number of 2 or more) among the many usable pixels is actually operated. And a step of operating each drawing head while moving each drawing head relative to the drawing surface in the scanning direction to form the two-dimensional pattern on the drawing surface. In .

  The use pixel can be set based on an actual inclination angle formed by the actual pixel column direction on the drawing surface indicated by the drawing point group and the scanning direction.

  The step of setting so that the use pixel actually operates may include a step of designating the use pixel and a step of changing the setting so that only the use pixel is actually operated.

  Here, “operating the drawing head while moving each drawing head relative to the drawing surface in the scanning direction” is a form in which drawing is continuously performed while the drawing head is constantly moved. Alternatively, the drawing operation may be performed by moving the drawing head stepwise and stopping the drawing head at the position of each movement destination.

  According to the drawing apparatus and the drawing method of the present invention, the number of pixels that can minimize the influence of the attachment angle error and pattern distortion of the drawing head is set as the use pixel, and further the influence of the remaining attachment angle error and pattern distortion. Can be smoothed by the effect of filling by multiple drawing, so that the portion where the drawing is redundant or the portion where the drawing is insufficient is minimized and the resolution of the two-dimensional pattern formed on the drawing surface is reduced. Unevenness in density can be reduced.

  Further, according to the aspect in which the use pixel specifying means includes the position detection means and the selection means, skill is required that the operator manually sets the use pixels by visually confirming the reference drawing result. It is possible to automatically set the drawing apparatus by designating the number of pixels used so that the influence of the drawing head mounting angle error and pattern distortion can be minimized without requiring any work.

  Further, the selection means is configured to identify one representative light spot sequence and based on the detection results of the positions of at least two light spots among the light spots forming the representative light spot train and the neighboring light spot trains. According to the aspect in which the actual inclination angle is specified, an appropriate actual inclination angle is specified even when the direction of each pixel column projected on the drawing surface is different for each pixel column due to the influence of residual pattern distortion. Then, the use pixel can be selected. In particular, if the light spot sequence near the center is selected as the representative light spot sequence, the overall resolution and density unevenness due to the effect of pattern distortion of the two-dimensional pattern formed on the drawing surface is reduced. The effect is further increased.

  Further, the selecting means may identify a plurality of representative light spot sequences and based on the detection results of the positions of at least two light spots among the light spots forming each representative light spot train and the neighboring light spot trains. Even if the individual actual tilt angles are specified and the representative values thereof are used as the actual tilt angles, the direction of each pixel column projected on the drawing surface is different for each pixel column due to the residual pattern distortion. However, it is possible to specify an appropriate actual inclination angle, select a pixel to be used, and reduce the overall resolution and density unevenness due to the effect of pattern distortion of the two-dimensional pattern formed on the drawing surface. The effect to do can be further enhanced.

  Further, only (N-1) pixels constituting every second pixel column or pixels constituting a group of adjacent pixel rows corresponding to 1 / N of the total number of usable pixel rows are used. According to the aspect in which the reference drawing can be performed, it is possible to obtain a simple single drawing pattern that is simpler than the multiple drawing pattern by the reference drawing. It becomes easy to specify, and it becomes easier to specify the optimal use pixel.

  Further, according to the aspect in which the image data is converted so that the dimensions of the predetermined portion coincide with each other, the dimension of the two-dimensional pattern indicated by the image data is made to coincide with the dimension of the predetermined portion that can be realized by the designated use pixel. A high-definition pattern as shown in the two-dimensional pattern can be formed on the drawing surface.

  Hereinafter, an exposure apparatus, which is one embodiment of a drawing apparatus of the present invention, will be described in detail with reference to the drawings.

  As shown in FIG. 1, the exposure apparatus 10 according to the present embodiment includes a flat plate-like moving stage 14 that holds a sheet-like photosensitive material 12 by adsorbing to the surface. Two guides 20 extending along the stage moving direction are installed on the upper surface of the thick plate-shaped installation table 18 supported by the four legs 16. The stage 14 is arranged so that the longitudinal direction thereof faces the stage moving direction, and is supported by the guide 20 so as to be reciprocally movable. The exposure apparatus 10 is provided with a stage driving device 124 that drives the stage 14 as a moving means along the guide 20.

  A U-shaped gate 22 is provided at the center of the installation base 18 so as to straddle the movement path of the stage 14. Each end of the U-shaped gate 22 is fixed to both side surfaces of the installation base 18. A scanner 24 is provided on one side of the gate 22 and a plurality of (for example, two) sensors 26 for detecting the front and rear ends of the photosensitive material 12 are provided on the other side. The scanner 24 and the sensor 26 are respectively attached to the gate 22 and fixedly arranged above the moving path of the stage 14. Note that the scanner 24, the sensor 26, the stage driving device 124, and the like are connected to a controller 160 that controls the operation and timing of these units. Here, for explanation, an X axis and a Y axis that are orthogonal to each other are defined in a plane parallel to the surface of the stage 14 as shown in FIG.

  A slit formed in a “<” shape that opens in the direction of the X-axis at the upstream edge (hereinafter sometimes simply referred to as “upstream”) along the scanning direction of the stage 14. 10 are formed at equal intervals. Each slit 28 includes a slit 28 a located on the upstream side and a slit 28 b located on the downstream side. The slit 28a and the slit 28b are orthogonal to each other, and the slit 28a has an angle of −45 degrees and the slit 28b has an angle of +45 degrees with respect to the X axis. Single cell type photodetectors 122 are incorporated at positions below the respective slits 28 in the stage 14. Each photodetector 122 is connected to a position specifying unit 126 described later, and the position specifying unit 126 is connected to an arithmetic device 130 that is a selection unit that performs use pixel selection processing.

  The slit 28, the photodetector 122, and the position specifying unit 126 constitute a position detecting unit 120 that is a position detecting unit. A use pixel designation unit 140 that is a use pixel designation unit includes the position detection unit 120 and the calculation device 130.

As shown in FIGS. 2 and 3B, the scanner 24 includes ten exposure heads 30 arranged in a matrix of 2 rows and 5 columns. In the following, when individual exposure heads arranged in the m-th row and the n-th column are shown, they are expressed as an exposure head 30 _mn .

  Each exposure head 30 is attached to the scanner 24 so that the pixel column direction of an internal digital micromirror device (DMD) 36 to be described later forms a predetermined inclination angle θ with the scanning direction. Therefore, the exposure area 32 by each exposure head 30 is a rectangular area inclined with respect to the scanning direction. As the stage 14 moves, a strip-shaped exposed region 34 is formed in the photosensitive material 12 for each exposure head 30.

In the following, when an exposure area by individual exposure heads arranged in the m-th row and the n-th column is indicated, it is expressed as an exposure area 32 _mn .

Further, as shown in FIGS. 3A and 3B, exposure of each row arranged in a line so that each of the strip-shaped exposed regions 34 partially overlaps the adjacent exposed region 34 is performed. Each of the heads 30 is arranged so as to be shifted in the arrangement direction by a predetermined interval (a natural number times the long side of the exposure area, twice in this embodiment). Therefore, can not be exposed portion between the exposure area _{32 11} in the first row and the exposure area _{32 12,} it can be exposed by the second row of the exposure area _{32 21.}

  The center position of each exposure head 30 is substantially matched with the positions of the ten slits 28 described above. Further, the size of each slit 28 is set to sufficiently cover the width of the exposure area 32 by the corresponding exposure head 30.

  As shown in FIGS. 4 and 5, each of the exposure heads 30 includes a DMD 36 manufactured by Texas Instruments, Inc. as a spatial light modulation element that modulates incident light for each pixel unit according to image data. ing. The DMD 36 is connected to a controller 160 that includes a data processing unit and a mirror drive control unit. The data processing unit of the controller 160 generates a control signal for driving and controlling each micromirror in the use area on the DMD 36 for each exposure head 30 based on the input image data. The mirror drive control unit controls the angle of the reflection surface of each micromirror of the DMD 36 for each exposure head 30 based on the control signal generated by the image data processing unit.

  As shown in FIG. 4, on the light incident side of the DMD 36, there is provided a laser emission portion in which the emission end portion (light emission point) of the optical fiber is arranged in a line along the direction that coincides with the long side direction of the exposure area 32. The fiber array light source 38, the lens system 40 for correcting the laser light emitted from the fiber array light source 38 and condensing it on the DMD, and the mirror 42 for reflecting the laser light transmitted through the lens system 40 toward the DMD 36 Arranged in order. In FIG. 4, the lens system 40 is schematically shown.

  As shown in detail in FIG. 5, the lens system 40 has a pair of combination lenses 44 that collimate the laser light emitted from the fiber array light source 38, and the light quantity distribution of the collimated laser light becomes uniform. In this way, a pair of combination lenses 46 for correction and a condensing lens 48 for condensing the laser light whose light quantity distribution is corrected on the DMD 36 are configured.

  On the light reflection side of the DMD 36, a lens system 50 is disposed that forms an image of the laser light reflected by the DMD 36 on the exposure surface 12A that is the drawing surface of the photosensitive material 12. The lens system 50 includes two lenses 52 and 54 arranged so that the DMD 36 and the exposure surface 12A of the photosensitive material 12 (hereinafter, notation of reference numeral 12A) is in a conjugate relationship.

  In the present embodiment, the laser light emitted from the fiber array light source 38 is substantially magnified five times, and then the light from each micromirror on the DMD 36 is reduced to about 5 μm by the lens system 50. Is set to

  As shown in FIG. 6, the DMD 36 is a mirror device in which a large number of micromirrors 58 that constitute pixels (pixels) are arranged in a lattice pattern on an SRAM cell (memory cell) 56. In this embodiment, a DMD 36 in which 1024 columns × 768 rows of micromirrors 58 are arranged is used. Of these, the micromirrors 58 that can be driven by the controller 160 connected to the DMD 36, that is, usable, are used in many ways. It is assumed that the pixel array is composed of only 1024 columns × 256 rows constituting a pixel array composed of possible pixels. The data processing speed of the DMD 36 is limited, and the modulation speed per line is determined in proportion to the number of micromirrors to be used. Thus, by using only some of the micromirrors in this way, Modulation speed increases. Each micromirror 58 is supported by a support column, and a material having high reflectivity such as aluminum is deposited on the surface thereof. In the present embodiment, the reflectance of each micromirror 58 is 90% or more, and the arrangement pitch thereof is 13.7 μm in both the vertical direction and the horizontal direction. The SRAM cell 56 is a silicon gate CMOS manufactured on a normal semiconductor memory manufacturing line via a support including a hinge and a yoke, and is configured monolithically (integrated) as a whole.

  When an image signal representing the density of each point constituting a desired two-dimensional pattern in binary is written in the SRAM cell 56 of the DMD 36, each micromirror 58 supported by the column is arranged with the DMD 36 centered on the diagonal line. It is inclined to any one of ± α degrees (for example, ± 10 degrees) with respect to the substrate side. FIG. 7A shows a state in which the micromirror 58 is tilted to + α degrees in the on state, and FIG. 7B shows a state in which the micromirror 58 is tilted to −α degrees in the off state. Therefore, by controlling the inclination of the micromirror 58 in each pixel of the DMD 36 as shown in FIG. 6 according to the image signal, the laser light B incident on the DMD 36 is reflected in the inclination direction of each micromirror 58. The

  FIG. 6 shows an example in which a part of the DMD 36 is enlarged and each micromirror 58 is controlled to + α degrees or −α degrees. The on / off control of each micromirror 58 is performed by the controller 160 connected to the DMD 36. Further, a light absorber (not shown) is arranged in the direction in which the laser beam B reflected by the off-state micromirror 58 travels.

  As shown in FIG. 8, the fiber array light source 38 includes a plurality of (for example, 14) laser modules 60, and one end of a multimode optical fiber 62 is coupled to each laser module 60. A multimode optical fiber 64 having a smaller cladding diameter than the multimode optical fiber 62 is coupled to the other end of the multimode optical fiber 62. As shown in detail in FIG. 9, seven ends of the multimode optical fiber 64 opposite to the multimode optical fiber 62 are arranged along the direction orthogonal to the scanning direction, and these are arranged in two rows to emit laser light. A portion 66 is configured.

  As shown in FIG. 9, the laser emitting portion 66 constituted by the end portion of the multimode optical fiber 64 is sandwiched and fixed between two support plates 68 having a flat surface. Further, a transparent protective plate such as glass is preferably disposed on the light emitting end face of the multimode optical fiber 64 for protection. The light exit end face of the multi-mode optical fiber 64 has high light density and is likely to collect dust and easily deteriorate. However, the protective plate as described above prevents the dust from adhering to the end face and deteriorates. Can be delayed.

In the present embodiment, double exposure processing is performed by the exposure apparatus 10, and the above-described set inclination angle θ of each exposure head 30, that is, each DMD 36, is ideal as designed without any mounting angle error of the exposure head 30. In such a state, an angle slightly larger than the angle θ _{ideal at} which double exposure is performed using the micromirror 58 of 1024 columns × 256 rows is adopted. This angle θ _ideal is the number N of N exposures, the number s of micromirrors 58 forming each pixel column of the usable micromirrors 58, the pixel pitch p in the pixel column direction of the usable micromirrors 58, and the scanning direction. For the pixel column pitch δ of the usable micromirror 58 along the direction orthogonal to

Given by. As described above, the DMD 36 in the present embodiment includes a large number of micromirrors 58 having equal vertical and horizontal arrangement pitches arranged in a rectangular lattice shape.

And the above equation (1) is

It becomes. In this embodiment, since s = 256 and N = 2 as described above, the angle θ _ideal is about 0.45 degrees from the equation (3). Therefore, for example, an angle of about 0.50 degrees may be employed as the set inclination angle θ. It is assumed that the exposure apparatus 10 is initially adjusted so that the mounting angle of each exposure head 30, that is, each DMD 36 is close to the set inclination angle θ within an adjustable range.

  FIG. 10 is an explanatory view showing an example of unevenness in the pattern on the exposure surface due to the influence of the mounting angle error of one exposure head 30 and the pattern distortion in the exposure apparatus 10 initially adjusted as described above. . In the following drawings and description, the mth light spot row on the exposure surface, which is composed of light spots projected on the exposure surface, which is a pixel drawing point drawn on the drawing surface by the exposure head 30, is shown. It is assumed that r (m), the nth light spot column on the exposure surface is represented as c (n), and the light spot in the mth row and nth column is represented as P (m, n). The upper part of FIG. 10 shows the pattern of the light spot group from the usable micromirror 58 projected onto the exposure surface of the photosensitive material 12 with the stage 14 being stationary, and the lower part is shown in the upper part. This shows the state of the exposure pattern formed on the exposure surface when continuous exposure is performed by moving the stage 14 in a state in which a pattern of light spots appears. In FIG. 10, for convenience of explanation, the exposure pattern of the odd-numbered columns of the micromirrors 58 that can be used and the exposure pattern of the even-numbered columns are shown separately. However, the exposure patterns on the actual exposure surface are 2 Two exposure patterns are superimposed.

In the example of FIG. 10, since the set inclination angle θ is slightly larger than the angle θ _ideal and fine adjustment of the attachment angle of the exposure head 30 is difficult, the actual attachment angle is the above set inclination. As a result of the slight deviation from the angle θ, the portion corresponding to the end of each pixel column, in both the exposure pattern by the odd column and the exposure pattern by the even column, at any point on the exposure surface, that is, In the connection portion between the pixel columns, the exposure is more redundant than the ideal double exposure state, that is, the exposure state is more overlapped than the double exposure state, resulting in density unevenness.

  Furthermore, in the example of FIG. 10, angular distortion is generated, which is an example of pattern distortion appearing on the exposure surface, and the inclination angle of each pixel column projected on the exposure surface is not uniform. Causes of such angular distortion include various aberrations and alignment deviations of the optical system between the DMD 36 and the exposure surface, distortion of the DMD 36 itself, micromirror placement errors, and the like. The angular distortion appearing in the example of FIG. 10 is a distortion in which the tilt angle with respect to the scanning direction is smaller as the pixel column on the left side of the figure is larger and larger as the pixel line on the right side of the figure is larger. As a result of this angular distortion, the width of the portion where the above-described exposure is redundant is smaller as the portion shown on the left side of the drawing on the exposure surface and larger as the portion shown on the right side of the drawing.

  In order to reduce the unevenness appearing on the exposure surface as described above, in the present embodiment, the exposure head is configured using the above-described combination of the slit 28 and the photodetector 122 that constitutes the position detection unit 120 and the position specifying unit 126. Every 30th, the position of the light spot projected on the exposure surface, that is, the position of the pixel drawing point drawn on the drawing surface is detected, and then the arithmetic unit 130 connected to the position specifying unit 126 detects the light spot, that is, the pixel. An actual inclination angle θ ′ of a drawing row composed of drawing points is specified, and a use pixel selection process for selecting a micromirror to be actually used for the main exposure process is performed based on the actual inclination angle θ ′. Hereinafter, the specification of the actual inclination angle θ ′ and the used pixel selection process will be described with reference to FIGS. 11 and 12.

  FIG. 11 is a plan view showing the positional relationship between the exposure area 32 by one DMD 36 and the corresponding slit 28 as viewed from above. As described above, the size of the slit 28 is set to sufficiently cover the width of the exposure area 32.

  In the present embodiment, the 512th light spot row positioned substantially at the center of the exposure area 32 is used as a representative light spot train, and the angle formed by the direction of the representative light spot train and the scanning direction is the actual inclination angle θ ′. Measure as Specifically, the micromirrors 58 in the 512th column, the first row, and the 512th column, the 256th row on the DMD 36 are turned on, and the position detection unit 120 performs the light spot P (1 512) and P (256, 512) are detected, and the inclination angle of the straight line connecting these light spots with respect to the scanning direction is specified as the actual inclination angle θ ′.

  FIG. 12 is a plan view illustrating a method for detecting the position of the light spot P (256, 512). First, in a state in which P (256, 512) is lit, the stage 14 is slowly moved by driving the stage driving device 124, and the slit 28 is relatively moved along the Y-axis direction, so that the light spot P (256, 512). The slit 28 is positioned at an arbitrary position such that is located between the upstream slit 28a and the downstream slit 28b. At this time, the coordinates of the intersection of the slit 28a and the slit 28b are (X0, Y0). The value of the coordinates (X0, Y0) is determined and recorded from the moving distance of the stage 14 to the above position indicated by the drive signal given to the stage 14 and the known X-direction position of the slit 28. .

  Next, the stage 14 is moved, and the slit 28 is relatively moved to the right in FIG. 12 along the Y axis. Then, as indicated by a two-dot chain line in FIG. 12, the stage 14 is stopped when the light at the light spot P (256, 512) passes through the left slit 28b and is detected by the photodetector. The coordinates of the intersection of the slit 28a and the slit 28b at this time are recorded as (X0, Y1).

  This time, the stage 14 is moved in the opposite direction, and the slit 28 is moved relative to the left in FIG. 12 along the Y axis. Then, as indicated by a two-dot chain line in FIG. 12, the stage 14 is stopped when the light at the light spot P (256, 512) passes through the right slit 28a and is detected by the photodetector. The coordinates of the intersection of the slit 28a and the slit 28b at this time are recorded as (X0, Y2).

  From the above measurement results, the coordinates (X, Y) of the light spot P (256, 512) are determined by the calculation of X = X0 + (Y1-Y2) / 2, Y = (Y1 + Y2) / 2. By the same measurement, the coordinates of the light spot P (1,512) are also determined, the inclination angle of the straight line connecting the light spots P (1,512) and P (256,512) is derived, and the actual inclination angle θ ′. As specified.

  The position of each light spot is detected by the position specifying unit 126 connected to the photodetector 122. That is, based on information indicating that the position specifying unit 126 has detected each light spot of the photodetector 122 and information input from the controller 160 indicating the position of the stage 14 when each light spot is detected. Thus, the position of each light spot is obtained by the above method.

  Thereafter, the arithmetic device 130 inputs information indicating the position of each light spot and specifies the actual inclination angle θ ′. Then, as will be described later, the arithmetic device 130 further performs a use pixel selection process for selecting a micromirror that is actually used for the main exposure process based on the specified actual inclination angle θ ′.

  In the position detection by the position detection unit 120, the stage 14 is moved along the guide 20 by driving the stage driving device 124 under the control of the controller 160. Therefore, the stage driving device 124, the guide 20, the stage 14, and the controller 160 are moved. Are also included in the components constituting the position detection unit 120.

The arithmetic unit 130 uses the specified actual inclination angle θ ′,

The natural number T closest to the value t satisfying the above relationship is derived, and the first to T-th row micromirrors on the DMD 36 are selected as micromirrors that are actually used during the main exposure. As a result, in the representative region near the light spot row in the 512th row, the total of the portion where the exposure is redundant with respect to the ideal double exposure and the portion where the exposure is insufficient with respect to the ideal double exposure. A micromirror having a minimum value can be selected as a micromirror to be actually used.

  Here, instead of deriving the natural number closest to the above value t, the minimum natural number greater than or equal to the value t may be derived. In that case, in the representative region near the light spot row in the 512th row, the portion where the exposure is redundant with respect to the ideal double exposure is minimized, and the exposure with respect to the ideal double exposure is performed. A micromirror that does not cause an insufficient portion can be selected as a micromirror to be actually used. Or it is good also as deriving the maximum natural number below value t. In that case, in the representative region near the light spot row in the 512th row, the portion where the exposure is insufficient for the ideal double exposure is minimized, and the exposure is performed for the ideal double exposure. A micromirror that does not produce a redundant portion can be selected as a micromirror that is actually used.

  That is, information indicating the actually used micromirrors selected by the arithmetic device 130 (also information indicating unused pixels) is input to the setting changing unit 150. Note that, among the usable pixels, the used pixel specifying unit 140 and the setting changing unit 150 may be integrally configured as a used pixel setting unit that sets the used pixel to actually move.

  In FIG. 13, after the setting of the controller 160 is changed by the setting changing unit 150 so that only the micromirror selected as the actually used micromirror is actually operated, the control of the controller 160 whose setting is changed is used. It is explanatory drawing which showed how the nonuniformity on the exposure surface shown in FIG. 10 is improved at the time of the main exposure which performs exposure. In this example, T = 253 is derived as the natural number T, and the micromirrors in the first to 253rd rows are actually moved during the main exposure. The micromirrors in the 254th to 256th lines that were not selected are always sent a signal to set the angle of the micromirror to the off state angle, and these micromirrors are substantially used for the main exposure. Not.

  In the present embodiment, as described above, the actual tilt angle θ ′ is measured using the 512th light spot sequence as the representative light spot sequence, and the micromirror 58 to be used is selected by the formula (4) using the actual tilt angle θ ′. Therefore, as shown in FIG. 13, in the vicinity of the 512th light spot row, the redundancy and deficiency of exposure at the connection portion between the pixel rows are almost completely eliminated, and a uniform double layer extremely close to the ideal state is obtained. Exposure is realized.

  In the left region of FIG. 13 (c (1) side in the figure), the inclination angle of the light spot sequence on the exposure surface is smaller than the inclination angle in the region near the center due to the above-described angular distortion. . Therefore, in the exposure by the micromirror selected by the actual inclination angle θ ′ measured with reference to the light spot row c (512) near the center, as shown in the figure, the exposure pattern by the odd-numbered micromirror and the even row In each of the exposure patterns by the micromirrors, a portion where the exposure is insufficient occurs slightly at the connection portion between the pixel columns. However, in the actual exposure pattern in which the exposure pattern of the odd-numbered columns and the exposure pattern of the even-numbered columns shown in the figure are overlapped, the portions where the above exposure is insufficient are interpolated with each other, and the influence of angular distortion is double-exposed. It can be leveled by the effect of make up.

  Further, in the region on the right side of FIG. 13 (c (1024) side in the drawing), the tilt angle of the light spot array on the exposure surface is larger than the tilt angle in the region near the center due to the angular distortion described above. ing. Therefore, in the exposure by the micromirror selected by the actual inclination angle θ ′ measured with reference to the light spot row c (512) near the center, as shown in the figure, the exposure is performed at the connection portion between the pixel rows. A little redundant part remains. However, in the actual exposure pattern in which the exposure pattern of the odd-numbered columns and the exposure pattern of the even-numbered columns shown in the figure are overlapped, the density unevenness due to the redundant portion of the remaining exposure is due to the effect of filling by double exposure. They are leveled together and become inconspicuous.

  As described above, according to the exposure apparatus 10 of the present embodiment, the resolution and density unevenness due to the influence of the mounting angle error and pattern distortion of each exposure head 30 are spread over the entire exposure area 32 of the exposure head 30. Can be reduced.

  In addition to the angular distortion described in the above example, there are various forms of pattern distortion that can occur on the exposure surface. As an example, as shown in FIG. 14A, there is a form of magnification distortion in which the light from each micromirror 58 on the DMD 36 reaches the exposure area 32 on the exposure surface at a different magnification. As another example, as shown in FIG. 14B, there is a form of beam diameter distortion in which the light from each micromirror 58 on the DMD 36 reaches the exposure area 32 on the exposure surface with a different beam diameter. is there. These magnification distortion and beam diameter distortion are mainly caused by various aberrations and alignment deviation of the optical system between the DMD 36 and the exposure surface. As another example, there is a form of light amount distortion in which light beams from the micromirrors 58 on the DMD 36 reach the exposure area 32 on the exposure surface with different light amounts. In addition to various aberrations and misalignment, this light amount distortion includes the positional dependency of the transmittance of the optical element between the DMD 36 and the exposure surface (for example, the lenses 52 and 54 in FIG. 5 which is a single lens) and the light amount due to the DMD 36 itself. Caused by unevenness. These forms of pattern distortion also cause unevenness in resolution and density in the pattern formed on the exposure surface. However, according to the exposure apparatus 10 according to the above-described embodiment, the pattern distortion residual elements in these forms after selecting the micromirrors actually used for the main exposure are the same as the angular distortion residual elements described above. It can be leveled by the effect of offset by double exposure. Therefore, according to the exposure apparatus 10 of the present embodiment, resolution and density unevenness due to the influence of pattern distortion other than angular distortion can be reduced over the entire exposure area 32 of each exposure head 30.

  The exposure apparatus 10 which is one embodiment of the drawing apparatus of the present invention has been described in detail above. However, the above is only an example, and various modifications can be made without departing from the scope of the present invention.

  For example, in the above embodiment, one light spot sequence projected on the exposure surface is selected as the representative light spot train, and the angle formed by the direction of the representative light spot train and the scanning direction is set as the actual inclination angle θ ′. However, instead of this, for each of a plurality of light spot rows from the usable light spot mirrors projected on the exposure surface, the direction of the light spot row and the scanning direction are individually formed. The actual tilt angle is measured, and the median value, average value, maximum value, minimum value, etc. of these individual tilt angles are set as the actual tilt angle θ ′, and the micromirrors actually used for the main exposure by the above equation (4) or the like It is good also as a form which selects. Here, if the median value or the average value of the individual inclination angles is set to the actual inclination angle θ ′, it is possible to realize the main exposure with a good balance between the portions where the exposure is redundant and the portions where the exposure is insufficient. It is possible to realize the main exposure in which the total of the redundant part and the deficient part is minimized and the number of light points of the redundant part and the deficient part is equal. On the other hand, if the maximum value of the individual inclination angle is set to the actual inclination angle θ ′, it is possible to realize the main exposure that places more importance on the removal of the portion where the exposure is redundant, for example, the portion where the exposure is insufficient is minimized. It is possible to realize the main exposure that is suppressed to a low level and does not cause a redundant drawing. In addition, if the minimum value of the individual inclination angle is set to the actual inclination angle θ ′, it is possible to realize the main exposure that places more importance on the removal of the portion where the exposure is insufficient. For example, the portion where the exposure is redundant is minimized. It is possible to realize the main exposure that is suppressed to a low level and does not cause a portion where drawing is insufficient.

  In addition, in the above embodiment, based on at least two light spot positions in the representative light spot row, the angle formed by the direction of the representative light spot row and the scanning direction is specified as the actual inclination angle θ ′. However, the specification of this angle is not necessarily limited to that performed based only on the position of the light spot in the representative light spot sequence. For example, an angle obtained from one or a plurality of light spot positions in the representative light spot array and one or a plurality of light spot positions in the light spot array near the representative light spot array is set as an actual inclination angle θ ′. You may specify. Specifically, the position of one light spot in the representative light spot array, and the position of one or more light spots included in a nearby light spot array that is linearly aligned with the light spot in the scanning direction. And the actual inclination angle θ ′ can be obtained from the position information. Alternatively, an angle obtained based on the positions of at least two light spots (for example, two light spots straddling the representative light spot array) in the light spot array in the vicinity of the representative light spot array is set as an actual inclination angle θ ′. You may specify.

  In the above embodiment, the set of the slit 28 and the single cell type photodetector is used as a means for detecting the position of the light spot on the exposure surface. For example, a two-dimensional detector or the like may be used.

  Further, in the above-described embodiment, the arithmetic device 130 that has received the position detection result of the light spot by the set of the slit 28 and the photodetector 122 and the position specifying unit 126 obtains the actual inclination angle θ ′, and further, the arithmetic device 130. The operation of the use pixel designating unit 140, which is the use pixel designating means, selects the use pixel based on the actual tilt angle θ ′. However, the use pixel designating unit performs the derivation of the actual tilt angle θ ′. It is good also as a form which designates the use pixel used for N double drawing among the micromirrors which can be used without it. Furthermore, for example, a reference pixel that will be described later using a usable micromirror is used, and a pixel to be manually used to specify the micromirror to be used by the operator by visually confirming the resolution of the reference exposure result or checking the density unevenness. The form of the designation means is also included in the scope of the present invention.

  Further, as a modification of the above-described embodiment, among the usable micromirrors, (N-1) micromirrors constituting every second pixel column, or adjacent to each other corresponding to 1 / N of the total number of pixel rows. Using only the micromirrors constituting the group of pixel rows to be performed, the reference exposure is performed so as to realize a state close to an ideal single exposure, and the main exposure of the micromirrors used for the reference exposure. It is good also as specifying the micromirror which is not used for. That is, by specifying a micromirror that is not used for the main exposure, it is possible to specify a micromirror that is used for the main exposure among the micromirrors that are pixels used for the reference exposure.

  FIG. 15 is an explanatory diagram showing an example of a form in which reference exposure is performed using only micromirrors that constitute every (N-1) pixel rows. In this example, the main exposure is assumed to be double exposure, and therefore N = 2. First, reference exposure is performed using only the micromirrors corresponding to the odd-numbered light spot rows indicated by solid lines in FIG. 15A, and the reference exposure results are output as samples. The operator can visually check the resolution and density unevenness of the output reference exposure result or estimate the actual tilt angle to minimize the resolution and density unevenness. The micromirror used in the main exposure can be designated so that the exposure can be realized. For example, it is assumed that micromirrors other than those corresponding to the light spot array shown by hatching in FIG. 15B are actually used in the main exposure among the micromirrors constituting the odd-numbered pixel arrays. Can be specified. For even-numbered pixel columns, reference exposure may be performed separately in the same manner, and the micromirror used for the main exposure may be designated, or the same pattern as the pattern for the odd-numbered pixel columns may be applied. Good. By specifying the micromirrors used for the main exposure in this way, in the main exposure using both the odd-numbered and even-numbered micromirror rows, a state close to ideal double exposure can be realized. . The analysis of the reference exposure result is not limited to visual observation by the operator, and may be a mechanical analysis.

  FIG. 16 is an explanatory diagram showing an example of a mode in which reference exposure is performed using only micromirrors that constitute groups of adjacent pixel rows corresponding to 1 / N of the total number of pixel rows. In this example, the main exposure is assumed to be double exposure, and therefore N = 2. First, reference exposure is performed using only micromirrors corresponding to the light spots in the first to 128 (= 256/2) rows indicated by the solid line in FIG. 16A, and the reference exposure results are sampled. Output. The operator can visually check the resolution and density unevenness of the output reference exposure result or estimate the actual tilt angle to minimize the resolution and density unevenness. The micromirror used in the main exposure can be designated so that the exposure can be realized. For example, micromirrors other than those corresponding to the light spot array shown by hatching in FIG. 16B are designated as actually used in the main exposure among the micromirrors in the first to 128th rows. Can be done. For the micromirrors in the 129th to 256th lines, reference exposure may be separately performed in the same manner, and the micromirror used for the main exposure may be designated. The same pattern may be applied. By designating the micromirrors used for the main exposure in this way, a state close to an ideal double exposure can be realized in the main exposure using the entire micromirrors. The analysis of the reference exposure result is not limited to visual observation by the operator, and may be a mechanical analysis.

  In the above embodiment and the modified examples, the case where the main exposure is the double exposure has been described. However, the present invention is not limited to this, and any multiple exposure of the double exposure or more may be used. In particular, by setting the exposure to a triple exposure to a triple exposure, it is possible to achieve an exposure with a good balance between ensuring high resolution and reducing resolution and density unevenness.

  Further, in the exposure apparatus according to the embodiment and the modified example, the dimension of the predetermined part of the two-dimensional pattern represented by the image data is matched with the dimension of the corresponding part that can be realized by the selected use pixel. A mechanism for converting image data is preferably provided. By converting the image data in such a manner, a high-definition pattern according to a desired two-dimensional pattern can be formed on the exposure surface.

  In the description of the above embodiment, the driving mechanism of each part such as moving means is omitted, but conventionally known driving mechanisms can be used, for example, as a sliding mechanism. Can adopt a ball / rail system that moves the moving base on the rail, an air slide system, etc., a ball bearing, an air bearing, etc. can be adopted as the rotation mechanism, and a driving force transmission mechanism, A cam mechanism, a link mechanism, a rack / pinion mechanism, a ball screw / ball bush mechanism, an air slide mechanism, or a piston / cylinder mechanism can be employed. Further, a motor, a hydraulic actuator, a pneumatic actuator, or the like can be employed as the driving source.

  The exposure apparatus 10 is an example of a drawing apparatus of the present invention. The drawing apparatus of the present invention draws a drawing surface by N-fold drawing (N is a natural number of 2 or more) and displays a two-dimensional pattern represented by image data. A pixel array that is formed on a drawing surface and has a number of usable pixels arranged two-dimensionally and generates a drawing point group constituting the two-dimensional pattern according to the image data, that is, the above-mentioned A drawing head having a pixel array for drawing a pixel drawing point representing the two-dimensional pattern on a drawing surface, wherein a pixel column direction of the usable pixels and a scanning direction of the drawing head are set with a predetermined inclination The drawing apparatus further includes a moving means for moving the drawing surface relative to the drawing head in the scanning direction, and the multiple use of the drawing head. Among the active pixels, the used pixel specifying means for specifying the used pixels to be used for the N-fold drawing and the setting are changed so that only the specified used pixels among the usable pixels of the drawing head are actually operated. And a setting change means for performing.

  Note that the pixel array for generating the drawing point group can be a large number of micromirrors arranged in the DMD, and the large number of micromirrors arranged in accordance with the exposure / non-exposure state of each micromirror. A light beam group which is a drawing point group is emitted from these micromirrors to expose the exposure surface, that is, a pixel drawing point is drawn on the drawing surface. Further, as a pixel array different from the present embodiment, a large number of nozzles arranged for the ink jet method can be cited, and a large number of the arranged nozzles may correspond to the drawing / non-drawing state of each nozzle. The ink particle group which is the drawing point group is ejected from these nozzles to draw the drawing surface, that is, the pixel drawing point is drawn on the drawing surface.

  Note that “the pixel column direction of the usable pixels and the scanning direction of the drawing head form a predetermined tilt angle” means “the pixel column direction of the usable pixels and the relative scanning direction of the drawing surface with respect to the drawing head”. Means that the predetermined angle of inclination forms a predetermined inclination angle, and the predetermined inclination angle is determined from each pixel drawing point drawn on the drawing surface via each pixel constituting the pixel row. This can be indicated by the angle formed by the direction in which the pixel drawing point sequence extends and the scanning direction of the drawing surface with respect to the drawing head.

  Further, the pixel array of the drawing head emits each light beam for drawing a pixel drawing point representing a two-dimensional pattern on the drawing surface toward the drawing surface in correspondence with each pixel constituting the pixel array. Can be for. In this case, the use pixel designating unit obtains the position of the pixel in the pixel array based on the detection of the position of the pixel drawing point formed on the drawing surface upon receiving the irradiation of each light beam.

  In addition, the use pixel designation unit may include a position detection unit and a selection unit. Then, the position detecting means, when performing N-design drawing in a predetermined design, the portion corresponding to the connecting portion between the pixel columns constituting the pixel array becomes redundant, or each of the above It is possible to specify a portion where drawing corresponding to a connecting portion between pixel columns is insufficient. In addition, the selection unit specifies pixels corresponding to the specified drawing redundancy and drawing shortage, and removes the drawing redundancy pixels or compensates for the drawing shortage pixels, thereby performing the drawing redundancy portion. In addition, the used pixels used for the main exposure in the pixel array can be selected from the usable pixels so that the drawing deficiency is eliminated.

  In addition, the selection unit selects use pixels that are pixels used for the main exposure in the pixel array so that the number of pixel drawing points for the drawing redundancy is minimized and the pixel drawing points for the drawing shortage are eliminated. It can also be selected.

  In addition, the selection unit uses pixels that are pixels used for the main exposure in the pixel array such that the pixel drawing points for the drawing redundancy are eliminated and the number of the pixel drawing points for the drawing shortage is minimized. Can also be selected.

  Here, the form of the use pixel designation means for designating the use pixel used for N-fold drawing among the micromirrors that can be used without deriving the actual inclination angle θ ′ will be described.

  The form of use pixel designating means described below is a micromirror that constitutes every (N-1) pixel columns among the available micromirrors, or one that corresponds to 1 / N of the total number of pixel rows. Using only the micromirrors constituting the group of adjacent pixel rows, the reference exposure is performed so that the state close to the ideal single exposure can be realized, and the book among the micromirrors used for the reference exposure. This can be applied when a micromirror not used for exposure is designated.

  In the following description, a point that is a light spot projected on the exposure surface and becomes a drawing point when drawing is actually performed will be described as a pixel drawing point.

  FIG. 17 is a view showing a straight line extending in the X direction formed by pixel drawing points drawn on the exposure surface when acquiring the connecting portion displacement amount, and FIG. 17A does not cause the joining portion displacement amount. FIG. 17B is a diagram showing a state in which the above-mentioned connecting portion shift amount is generated and rendering becomes redundant, and FIG. 17C is a state in which the above-mentioned connecting portion shift amount is generated and drawing is insufficient. FIG. FIG. 18 is a diagram showing the correspondence between the state of the pixel column and the straight line drawn by the pixel column when acquiring the shift amount of the connecting portion of the micromirrors constituting the adjacent pixel columns in the pixel array. 19 is a diagram showing a part of a straight line exposed in the X-axis direction that is exposed when the connecting portion shift amount is acquired, and FIG. 20 is a diagram showing a reference scale. FIG. 18 is a diagram showing a state in which there is no connecting portion shift amount.

  The method of designating a micromirror to be used without derivation of the actual inclination angle θ ′ is a pixel adjacent to each other in a pixel array composed of ideally arranged pixels as designed for use in N double exposure. Based on the connecting portion between columns, a connecting portion shift amount that is a shift amount of the connecting portion between actual pixel columns is obtained, and a micromirror (that is, a pixel to be used) to be used is designated based on the connecting portion shift amount. Is. The connecting portion shift amount can be determined according to the number of pixel drawing points corresponding to redundant drawing or the number of pixel drawing points corresponding to insufficient drawing.

  When acquiring the above-mentioned connecting portion shift amount, only (N-1) micro-mirrors constituting a pixel row are used out of the designed pixels used for N double exposure in the exposure head. The exposure is performed so that the pixel drawing points exposed on the exposure surface form a straight line aligned in the X-axis direction orthogonal to the scanning direction (Y-axis direction). The straight line extending in the X-axis direction exposed on the exposure surface may be as thick as one pixel drawing point. The thickness may be equal to or more than two pixel drawing points. Note that an exposure method that uses only micromirrors that constitute every (N-1) pixel rows in the N-fold exposure is hereinafter referred to as “thinning reference exposure”. In the following description, it is assumed that thinning reference exposure is performed.

  Also, with respect to the drawing by the exposure head, the number of micrographs exceeds the number of pixel drawing points corresponding to the maximum amount of connecting portion deviation (hereinafter referred to as “the assumed amount of connecting portion deviation”) assumed for the portion where drawing becomes redundant. The exposure is performed so as not to use the mirror, that is, in a non-exposed state. The number of micromirrors corresponding to the assumed joint displacement amount is the pixel drawing point that is assumed to be overdrawn in the scanning direction on the exposure surface by the pixels constituting the adjacent pixel columns used for the N double exposure. It corresponds to the number of.

  Hereinafter, with respect to the case where the actual connecting portion shift amount is acquired based on the pixel drawing points drawn by the pixel rows adjacent to each other, FIG. 17 (a), (b), (c), and FIG. The description will be given with reference.

  When measuring the shift amount between the pixel rows Sa and Sb which are different drawing units, the drawing is performed so as to be adjacent to each other with the edges Fa and Fb of the pixel rows Sa and Sb being the drawing units in between. Blank pixels Sa (16, e) to which a predetermined number of continuous pixels are arranged including at least one of the respective pixels in each of the pixel columns Sa and Sb and arranged along the pixel column. Blank adjacent pixels Sa (15, e) and Sb (1) adjacent to both sides of the blank pixels Sa (16, e) to Sa (20, e) without drawing for five pixels by Sa (20, e). , E + 1). Then, each blank adjacent pixel drawn on the exposure surface is inserted between pixel drawing points Qa (15, e) and Qb (1, e + 1) drawn by Sa (15, e) and Sb (1, e + 1). The number of possible pixel drawing points and the number of the blank pixels Sa (16, e) to Sa (20, e) are compared to obtain the connecting portion shift amount between the pixel column Sa and the pixel column Sb. .

  Note that the state of the connecting portion shown in FIG. 17A corresponds to the state of the connecting portion shown in FIG. 18, and both show a state in which no shift occurs in the connecting portion. FIG. 17B shows a state in which the joining portion is displaced in a state where the drawing is redundant, and FIG. 17C shows a state in which the joining portion is displaced in a state where the drawing is insufficient. Show.

  The blank pixels Sa (16, e) to Sa (20, e) including the predetermined number of pixels are configured by the number of pixels slightly exceeding the assumed joint displacement amount. The white circle pixels in the pixel row Sa in FIG. 18 indicate that the exposure surface is not exposed by the pixel (micromirror), and the other black circle pixels are the pixel (micromirror). ) Indicates that the exposure surface is exposed.

  The blank pixel drawing point group may be arranged only in the pixel drawing point sequence Qa, or may be arranged only in the pixel drawing point sequence Qb. Or you may make it arrange | position over pixel drawing point sequence Qa and pixel drawing point sequence Qb.

  The lower part of FIG. 18 and FIG. 19 show straight lines extending in the X-axis direction drawn on the exposure surface as described above. The straight line portion La is a region exposed by the pixel column Sa in the pixel array, and the straight line portion Lb is a region exposed by the pixel column Sb in the pixel array. A straight line portion Le indicates a non-exposure straight line portion by a micromirror having the number of pixels corresponding to the assumed connecting portion shift amount, that is, a micromirror corresponding to the blank pixels Sa (16, e) to Sa (20, e). That is, the straight line portion Le corresponds to the blank pixel drawing point group J shown in FIG.

  Then, as described above, the exposure surface is exposed with the micromirror corresponding to the assumed joint displacement amount being unexposed, and a reference scale Ls as shown in FIG. 20 is separately exposed by the exposure head. The reference scale Ls is a straight line extending in the X-axis direction exposed by a micromirror that constitutes one pixel column in the pixel array, and is n, n + 1, n + 2, n + 3, n−1, n− Non-exposed linear portions by drawing with 2 and n-3 pixels (micromirrors) in an unexposed state and pixels (micromirrors) adjacent to the non-exposed pixels (micromirrors) in an exposed state L (n), L (n + 1), L (n + 2), L (n + 3), L (n-1), L (n-2) and L (n-3) are formed.

  Then, the number (n) of pixel drawing points of each straight line portion L (n) in the reference scale Ls is set to the same number as the number of micromirrors (here, n = 5) corresponding to the assumed joint displacement amount. In addition, the number of micromirrors corresponding to the amount of shift of the joint portion can be obtained by comparing the length of the straight portion Le with each of the straight portions L (n−3) to L (n + 3) in the reference scale Ls. it can.

  For example, if the length of the straight line portion Le is the same as that of the straight line portion L (n), the amount of shift of the joint portion is zero. And if the length of the straight line part Le is the same length as the straight line part L (n-3), the number of the micro mirrors corresponding to the said connection part shift | offset | difference amount is -3. That is, the pixel column Sa and the pixel column Sb are overlapped by three micromirrors, that is, three pixels. Therefore, by performing exposure by designating pixels to be used so that the three micromirrors in the connecting portion of the pixel column Sa and the pixel column Sb are not used in an unexposed state, the connection between the pixel drawing point sequences is performed. Unevenness of the part can be suppressed.

  Further, for example, if the length of the straight line portion Le is the same as the length of the straight line portion L (n + 2), the number of micromirrors corresponding to the above-described connecting portion shift amount is +2, and the pixel column Sa and the pixel column Two micromirrors are separated from Sb, and two pixels are insufficient. Therefore, by performing exposure by newly designating two micromirrors as used pixels so as to add two pixels to the connecting portion of the pixel column Sa and the pixel column Sb, the pixel drawing point sequence is Unevenness of the connecting portion can be suppressed.

  As described above, each of the above-described portions indicating a portion in which drawing corresponding to a connecting portion between the pixel columns becomes redundant or a portion in which drawing is insufficient when N-fold drawing in the predetermined design is performed. An image of the straight line portions La (Le), Lb, L (n) and an image of each straight line portion L (n ± 1)... Constituting the reference scale are acquired.

  Then, based on the information indicating the image of each straight line part, the shift amount of the connecting part in the part where the drawing is redundant or the part where the drawing is insufficient is acquired, and the drawing redundant part and the drawing insufficient part are compensated. As described above, a use pixel which is a pixel used for the main exposure in the pixel array is selected from the usable pixels. That is, the unused pixels in the usable pixels are specified so that unevenness does not occur in the joint portion, and the pixels excluding the specified unused pixels are selected as the used pixels.

  Then, it is set so that only the selected used pixel among the usable pixels is actually moved. Thereafter, the main exposure is performed according to the setting.

  It should be noted that the comparison of the length of the straight line portion Le with the length of the straight line portions L (n), L (n ± 1)... You may make it carry out by the apparatus of.

  In the exposure apparatus according to the above-described embodiment, the DMD that modulates light from the light source for each pixel is used as the pixel array. However, the present invention is not limited to this, and a light modulation element such as a liquid crystal array other than the DMD or a light source array (for example, LD array, organic EL array, etc.) may be used.

  Further, the operation mode of the exposure apparatus according to the above-described embodiment and the modified example may be a mode in which exposure is continuously performed while constantly moving the exposure head, or each step while moving the exposure head step by step. The exposure operation may be performed with the exposure head stationary at the position of the movement destination.

  Furthermore, the present invention is not limited to an exposure apparatus and an exposure method, and a drawing apparatus that draws an exposure surface by N-fold drawing (N is a natural number of 2 or more) and forms a two-dimensional pattern represented by the image data on the exposure surface. Any drawing method can be applied to any apparatus and method. As an example, for example, an ink jet printer or an ink jet printing method may be used. That is, in general, an ink jet recording head of an ink jet printer is formed with a nozzle that ejects ink droplets on a nozzle surface facing a recording medium (for example, recording paper or an OHP sheet). There are some in which an image can be recorded by multiple drawing by arranging a plurality of dots in a lattice pattern and tilting the head itself with respect to the scanning direction. In the ink jet printer employing such a two-dimensional arrangement, the present invention is applied even if the actual tilt angle of the head itself is deviated from the ideal tilt angle, or pattern distortion exists due to an arrangement error of the nozzle itself. By specifying the number of nozzles that can be used to minimize the effects of head mounting angle errors and pattern distortion, the remaining mounting angle errors and pattern distortion effects can be compensated by multiple drawing. Therefore, it is possible to reduce the resolution and density unevenness generated in the recorded image.

As mentioned above, although embodiment and modification of this invention were described in detail, these embodiment and modification are only an illustration, and the technical scope of this invention should be defined only by a claim. It goes without saying that it is a thing.

The perspective view which shows the external appearance of the exposure apparatus which is one Embodiment of the drawing apparatus of this invention 1 is a perspective view showing the configuration of a scanner of the exposure apparatus in FIG. (A) is a plan view showing an exposed area formed on the exposure surface of the photosensitive material, and (B) is a plan view showing an array of exposure areas by each exposure head. 1 is a perspective view showing a schematic configuration of an exposure head of the exposure apparatus of FIG. FIG. 1 is a plan view and a side view showing a detailed configuration of an exposure head of the exposure apparatus of FIG. 1 is a partially enlarged view showing the configuration of the DMD of the exposure apparatus of FIG. A perspective view for explaining the operation of the DMD The perspective view which shows the structure of a fiber array light source Front view showing arrangement of light emitting points in laser emitting section of fiber array light source Explanatory drawing showing an example of unevenness in the pattern on the exposure surface when there is an exposure head mounting angle error and pattern distortion The top view which showed the positional relationship of the exposure area by one DMD, and a corresponding slit. Plan view for explaining the method of measuring the position of the light spot on the exposure surface using a slit Explanatory drawing which shows the state where only the selected use pixel is actually moved and the unevenness generated in the pattern on the exposure surface is improved Explanatory drawing showing examples of various pattern distortions Explanatory drawing showing a first example of reference exposure Explanatory drawing showing a second example of reference exposure The figure which shows the straight line formed by the pixel drawing point drawn on the exposure surface when acquiring a connection part shift | offset | difference amount The figure which shows the correspondence with the state of the micromirror at the time of acquiring a joint part shift amount, and the straight line part formed by the pixel drawing point, The figure which shows the linear part extended in the X-axis direction exposed when acquiring a connection part shift | offset | difference amount Diagram showing reference scale

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Exposure apparatus 12 Photosensitive material 14 Moving stage 18 Installation stand 20 Guide 22 Gate 24 Scanner 26 Sensor 28 Slit 30 Exposure head 32 Exposure area 36 DMD
38 Fiber array light source 140 Use pixel designation means 150 Setting change means 160 Controller

Claims (26)

A drawing apparatus that draws a drawing surface by N-fold drawing (N is a natural number of 2 or more) and forms a two-dimensional pattern represented by image data on the drawing surface.
One or a plurality of drawing heads having a pixel array having a number of usable pixels arranged two-dimensionally and generating a drawing point group constituting the two-dimensional pattern according to the image data A drawing head attached to the drawing surface such that a pixel column direction of the usable pixels and a scanning direction of the drawing head form a predetermined inclination angle;
Moving means for moving each drawing head relative to the drawing surface in the scanning direction;
A drawing apparatus comprising: for each of the drawing heads, use pixel setting means for setting a use pixel to be used for the N-fold drawing among the plurality of usable pixels.   The use pixel setting unit sets the use pixel based on an actual inclination angle formed by an actual pixel row direction and the scanning direction on the drawing surface indicated by the drawing point group. The drawing apparatus according to claim 1.   The said use pixel setting means is provided with the use pixel designation | designated means which designates the said use pixel, and the setting change means which changes a setting so that only the said use pixel operates. Drawing device. The set inclination angle θ is the number s of pixels forming each pixel row of the usable pixels, the pixel pitch p in the pixel row direction of the usable pixels, and the usable along the direction orthogonal to the scanning direction. For pixel column pitch δ of pixels,

The drawing apparatus according to any one of claims 1 to 3, wherein the angle satisfies the following relationship.   5. The drawing apparatus according to claim 3, wherein the use pixel designating unit designates the use pixel in units of pixel rows.   The use pixel designating unit specifies an actual inclination angle formed by an actual pixel column direction on the drawing surface indicated by the drawing point group and the scanning direction, and between the actual inclination angle and the set inclination angle. 6. The drawing apparatus according to claim 3, wherein the use pixel is designated in units of pixel rows so as to absorb an error.   The use pixel specifying means sets a plurality of columns of drawing points on the drawing surface corresponding to a plurality of pixel columns of the usable pixels as a representative drawing point sequence, and for each of the plurality of representative drawing point sequences, 7. The individual actual inclination angle formed by the direction of the representative drawing point sequence and the scanning direction is specified, and a representative value of the individual inclination angle is set as the actual inclination angle. Drawing device.   The drawing apparatus according to claim 7, wherein the representative value is one of an average value, a median value, a maximum value, and a minimum value of the individual inclination angles.     9. The drawing apparatus according to claim 1, wherein the pixel array of each of the drawing heads generates a light point group as the drawing point group. The pixel array of each of the drawing heads generates a light spot group as the drawing point group,
The use pixel designation means is
For each of the drawing heads, position detecting means for detecting a position on the drawing surface of a light spot constituting the light spot group;
For each of the drawing heads, based on the detection result of the position detection unit, in the representative region including at least one drawing portion by a connecting portion between pixel rows of the used pixels on the drawing surface, the ideal The unused pixels in the usable pixels are specified so that the sum of the portion where the drawing is redundant with respect to the N-fold drawing and the portion where the drawing is insufficient with respect to the ideal N-fold drawing is minimized. 5. The drawing apparatus according to claim 3, further comprising selection means for selecting a pixel excluding the unused pixel as the used pixel. The pixel array of each of the drawing heads generates a light spot group as the drawing point group,
The use pixel designation means is
For each of the drawing heads, position detecting means for detecting a position on the drawing surface of a light spot constituting the light spot group;
For each of the drawing heads, based on the detection result of the position detection unit, in the representative region including at least one drawing portion by a connecting portion between pixel columns of the used pixels on the drawing surface, the ideal The number of drawing points in the usable pixel is equal to the number of drawing points in the portion where the drawing is redundant with respect to the N-fold drawing and the number of drawing points in the portion where the drawing is insufficient with respect to the ideal N-fold drawing. 5. The drawing apparatus according to claim 3, further comprising selection means for specifying a used pixel and selecting a pixel excluding the unused pixel as the used pixel. The pixel array of each of the drawing heads generates a light spot group as the drawing point group,
The use pixel designation means is
For each of the drawing heads, position detecting means for detecting a position on the drawing surface of a light spot constituting the light spot group;
For each of the drawing heads, based on the detection result of the position detection unit, in the representative region including at least one drawing portion by a connecting portion between pixel rows of the used pixels on the drawing surface, the ideal In order to minimize the portion where drawing becomes redundant with respect to N-fold drawing, and to prevent the occurrence of a portion where drawing is insufficient with respect to the ideal N-fold drawing, unused pixels in the usable pixels are set. 5. The drawing apparatus according to claim 3, further comprising selection means for specifying and selecting a pixel excluding the unused pixel as the used pixel. The pixel array of each of the drawing heads generates a light spot group as the drawing point group,
The use pixel designation means is
For each of the drawing heads, position detecting means for detecting a position on the drawing surface of a light spot constituting the light spot group;
For each of the drawing heads, based on the detection result of the position detection unit, in the representative region including at least one drawing portion by a connecting portion between pixel rows of the used pixels on the drawing surface, the ideal The unused pixels in the usable pixels are set so that the portion where the drawing is insufficient with respect to the N-fold drawing is minimized and the portion where the drawing is redundant with respect to the ideal N-fold drawing does not occur. 5. The drawing apparatus according to claim 3, further comprising selection means for specifying and selecting a pixel excluding the unused pixel as the used pixel.   The drawing device according to claim 10, wherein the unused pixels are specified in units of pixel rows.   Based on the detection result of the position of at least two light spots by the position detection means, the selection means determines the actual pixel column direction projected on the drawing surface indicated by the light spot group and the scanning direction. The drawing apparatus according to claim 10, wherein an actual inclination angle formed is specified, and the unused pixels are specified based on the actual inclination angle.   The selecting means sets one column of the light spots on the drawing surface corresponding to one of the pixel columns of the usable pixels as a representative light spot row, and the representative light spot row and its neighboring light spots. 16. The drawing apparatus according to claim 15, wherein the actual inclination angle is specified based on a detection result of the position detection unit by at least two light spots among light spots forming a row.   The selecting means sets a plurality of columns of the light spots on the drawing surface corresponding to a plurality of pixel columns of the usable pixels as a representative light spot row, and for each of the plurality of representative light spot rows, Based on the detection results of the position detection means of the positions of at least two light spots among the light spots forming the representative light spot train and the light spot train in the vicinity thereof, the direction of the representative light spot train and the scanning direction are 16. The drawing apparatus according to claim 15, wherein an individual actual inclination angle to be formed is specified, and a representative value of the individual inclination angle is set as the actual inclination angle.   The drawing apparatus according to claim 17, wherein the representative value is one of an average value, a median value, a maximum value, and a minimum value of the individual inclination angles.   In order to designate the use pixel in the use pixel designation means, for each of the drawing heads, among the many usable pixels, only the pixels constituting every (N−1) pixel rows with respect to N The drawing apparatus according to claim 3, further comprising reference drawing means for performing reference drawing using the.   In order to designate the use pixel in the use pixel designating means, for each of the drawing heads, among the many usable pixels, for the N, 1 / N of the total number of pixel rows of the usable pixels 5. The drawing apparatus according to claim 3, further comprising reference drawing means for performing reference drawing using only pixels constituting a group of pixel rows adjacent to each other corresponding to.   Data conversion means is further provided for converting the image data so that the size of the predetermined portion of the two-dimensional pattern represented by the image data matches the size of the corresponding portion that can be realized by the designated use pixel. The drawing apparatus according to any one of claims 1 to 20, wherein:   The drawing apparatus according to claim 1, wherein the pixel array is a spatial light modulator that modulates light from a light source for each pixel according to the image data.   The drawing apparatus according to claim 1, wherein the N is a natural number of 3 or more and 7 or less. One or a plurality of drawing heads having a pixel array that has a number of usable pixels arranged two-dimensionally and generates a drawing point group constituting a two-dimensional pattern represented by the image data according to the image data A drawing method using a drawing head attached to a drawing surface so that a pixel column direction of the usable pixels and a scanning direction of the drawing head form a predetermined inclination angle,
For each of the drawing heads, a step of setting a use pixel to be used for N-fold drawing (N is a natural number of 2 or more) of the large number of usable pixels;
A drawing method comprising the step of forming the two-dimensional pattern on the drawing surface by operating the drawing head while moving each drawing head relative to the drawing surface in the scanning direction. .   25. The use pixel is set based on an actual inclination angle formed by an actual pixel row direction and the scanning direction on the drawing surface indicated by the drawing point group. Drawing method.   25. The drawing according to claim 24, wherein the step of setting so that the use pixel actually operates includes the step of designating the use pixel and the step of changing the setting so that only the use pixel operates. Method.

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