JP2010134375A - Drawing apparatus and drawing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To draw an image at a high speed with high accuracy while correcting distortion caused by influences of an optical system. <P>SOLUTION: A light beam spatially modulated by 1,024 optical modulation elements arrayed in a line is generated in a head unit of a drawing apparatus. The beam is deflected by a polygon mirror having six reflection faces to scan the irradiation position of light on an object to draw an image. A rectangular test pattern is actually drawn in the drawing apparatus to obtain test pattern images 91a to 91f influenced by the distortion of the reflection faces or the like, and an object drawing region 92 is set in a common region 911 that is independent from the reflection faces. Then, a correction table is generated to convert an object pixel forming the object drawing region 92 into a logic pixel representing data inputted to the optical modulation elements. Upon drawing an image, the inputted drawing data are converted by referring to the correction table to draw the image in the object drawing region 92. Thereby, an image can be drawn at a high speed with high accuracy while correcting distortion caused by influences of the optical system. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for drawing an image on an object by light irradiation.

  Conventionally, a technique for recording an image by irradiating an object while scanning a single light beam with a deflector such as a polygon mirror or a galvanometer mirror is a pattern on a photosensitive material formed on a semiconductor substrate or glass substrate. Are used for recording images and recording images on printing members such as printing plates.

  In such a drawing apparatus, a measure for correcting distortion of an image to be drawn may be taken. For example, in the scanning drawing apparatus disclosed in Patent Document 1, a deflector is provided between a light source and a polygon mirror. And a control circuit for controlling the deflector. Then, the emission direction of the light beam emitted from the deflector is corrected by the control circuit in accordance with the tilt angle of each small divided surface obtained by dividing each reflective surface of the polygon mirror in the rotation direction.

Further, in the multi-beam scanning device disclosed in Patent Document 2, a correction refracting surface that corrects inherent scanning line bending resulting from the design of the multi-beam scanning device is provided in the lens of the optical system.
JP-A-2-149816 JP-A-11-109266

  By the way, when increasing the number of irradiation positions where drawing is performed at the same time to increase the drawing speed, it is required to accurately arrange a plurality of light sources and modulators. Further, if the area that can be irradiated by one scan increases by increasing the number of irradiation positions, the effects of lens aberration, polygon mirror surface tilt and distortion cannot be ignored.

  The present invention has been made in view of the above problems, and has as its main purpose to draw an image with high speed and high accuracy while correcting distortion due to the influence of an optical system.

  The invention according to claim 1 is a drawing apparatus that draws an image on an object by light irradiation, and includes a modulated light generating unit that generates a spatially modulated light beam, and deflecting the light beam. A deflection unit that scans the irradiation position of the light beam on the object in a predetermined scanning direction, and the irradiation position of the light beam in the scanning direction by moving the object relative to the deflection unit. A moving mechanism that moves in an intersecting direction, target coordinates corresponding to a target pixel array set in a region that can be drawn by each scanning of the irradiation position of the light beam, and the modulated light generation unit in each scanning A storage unit that stores a correction table indicating a relationship with a logical coordinate corresponding to a logical pixel array indicated by the logical drawing data input to the image, and a target image in each scan of the light beam with reference to the correction table. The target drawing data showing a sequence, and a data converter for converting into a logic drawing data indicating the logical pixel array having the target pixel array or higher resolution.

  A second aspect of the present invention is the drawing apparatus according to the first aspect, wherein the deflection unit deflects the light beam by reflecting the light beam on a plurality of reflecting surfaces while rotating. A mirror is provided, and the storage unit stores a correction table corresponding to each reflecting surface of the polygon mirror.

  The invention according to claim 3 is the drawing apparatus according to claim 2, wherein the number of rows and the number of columns of the target pixel array to be drawn on the object by each scanning of the irradiation position of the light beam is constant. It is.

  A fourth aspect of the present invention is the drawing apparatus according to the first aspect, wherein the deflection unit deflects the light beam by reflecting the light beam on a reflecting surface while swinging. Is provided.

  A fifth aspect of the present invention is the drawing apparatus according to any one of the first to fourth aspects, wherein a plurality of lines are aligned in a direction intersecting the scanning direction by irradiating the object with the light beam. The modulated light is irradiated to each of the positions.

  The invention according to claim 6 is the drawing apparatus according to claim 5, wherein the number of the plurality of positions is 50 or more.

  A seventh aspect of the present invention is the drawing apparatus according to the fifth or sixth aspect, wherein the modulated light generation unit is a space in which a light source unit and a plurality of diffraction grating type light modulation elements are linearly arranged. An optical modulator, and an optical system that converts light from the light source unit into linear light having a linear light beam cross section and guides the light to the spatial light modulator.

  The invention according to claim 8 is the drawing apparatus according to any one of claims 1 to 7, wherein a pixel pitch in the target pixel array is not less than 1 and not more than 50 times a pixel pitch in the logical pixel array. is there.

  The invention according to claim 9 is a drawing method for drawing an image on an object by irradiation of light, wherein a) a step of generating a light beam spatially modulated by a modulated light generation unit, and b) the light beam. Scanning the irradiation position of the light beam on the object in a predetermined scanning direction by a deflecting unit that deflects the light beam, and c) parallel to the steps a) and b) with respect to the deflecting unit. A step of moving the irradiation position of the light beam in a direction intersecting the scanning direction by relatively moving an object, and setting the irradiation position of the light beam within an area that can be drawn by each scanning A correction table indicating the relationship between the target coordinates corresponding to the target pixel array and the logical coordinates corresponding to the logical pixel array indicated by the logical drawing data input to the modulated light generation unit in each scan is stored in the storage unit Has been In the step a), referring to the correction table, the target drawing data indicating the target pixel array in each scan of the light beam is changed to logical drawing data indicating a logical pixel array having a resolution higher than the target pixel array. It is converted and input to the modulated light generator.

  A tenth aspect of the present invention is the drawing method according to the ninth aspect of the present invention, in which, before the step a), d) a test object while inputting data indicating a logical test pattern to the modulated light generation unit. A step of drawing a test pattern on the test object by scanning the irradiation position of the light beam on the top; and e) capturing the test pattern drawn on the test object to obtain a test pattern image And f) generating the correction table by comparing the logical test pattern with the test pattern image.

  An eleventh aspect of the present invention is the drawing method according to the ninth or tenth aspect, wherein the deflecting unit deflects the light beam by reflecting the light beam on a plurality of reflecting surfaces while rotating. And a storage table storing a correction table corresponding to each reflecting surface of the polygon mirror.

  A twelfth aspect of the present invention is the drawing method according to the ninth or tenth aspect, wherein the deflecting unit deflects the light beam by reflecting the light beam on a reflecting surface while swinging. Equipped with a galvanometer mirror.

  In the present invention, an image can be drawn at high speed and with high accuracy while correcting distortion due to the influence of the optical system. According to the second and eleventh aspects of the present invention, it is possible to individually correct image distortion caused by each surface of the polygon mirror.

  FIG. 1 is a perspective view showing a drawing apparatus 1 according to an embodiment of the present invention. The drawing apparatus 1 is a direct pattern drawing apparatus that draws an image, which is a wiring pattern, on an object 9 that is a flat printed board by irradiation with a light beam, and holds a head unit 11 that emits a light beam and the object 9. And a control unit 13 for controlling the head unit 11 and the moving mechanism 12. The moving mechanism 12 moves the object 9 in the Y direction (corresponding to the sub-scanning direction of the light beam) in FIG. 1 and images the drawing surface of the object 9 above the moving mechanism 12 and the object 9. A camera 2 is arranged. The control unit 13 is connected to the head unit 11, the moving mechanism 12, and the camera 2 to control each unit. A photosensitive material is applied to the drawing surface of the object 9, and drawing is performed when the photosensitive material is exposed to light beam irradiation.

  2 and 3 are diagrams showing the internal configuration of the head unit 11 in a simplified manner, and FIG. 3 shows the arrangement of optical elements in an expanded manner. The head unit 11 includes a modulated light generation unit 111 that generates a spatially modulated light beam, and a deflection unit 112 that scans the light beam in the X direction. The modulated light generator 111 is a light source 1111 that emits laser light, a linear light generator 1112 that is an optical system that converts light from the light source 1111 into linear light whose light beam cross section extends linearly in the Z direction, and And a spatial light modulator 1113 through which linear light is guided. The spatial light modulator 1113 is configured by 1024 light modulation elements of a diffraction grating type arranged linearly in the Z direction.

  In the present embodiment, a GLV (Grating Light Valve) element having minute fixed ribbons and movable ribbons alternately arranged is used as the light modulation element, and the movable ribbon moves up and down to change the depth of the diffraction grating. Thus, the light is modulated by switching between the diffraction state and the regular reflection state. The spatial light modulator 1113 individually controls light at each of the 1024 positions in the Z direction by controlling the reflective light modulation elements, which are GLV elements arranged in the Z direction. As a diffraction grating type optical modulator, in addition to the GLV element, for example, by arranging a plurality of fine electrodes on the surface of a material whose refractive index changes due to an electric field, an internal refraction is made utilizing the electro-optic effect. A total reflection type optical modulator capable of controlling the rate distribution (hereinafter referred to as “TIR (Total Internal Reflection) type optical modulator”) may be used. In the TIR type optical modulator, a periodic refractive index distribution is generated inside by the arranged electrodes, and diffraction occurs due to a phase difference in the light beam when the light beam passes through the inside (that is, TIR type light modulator). The modulator functions as a diffraction grating.)

  The deflection unit 112 of the head unit 11 includes a polygon mirror 1121 having six reflecting surfaces, a lens 1122 disposed on the front side of the polygon mirror 1121 in the light traveling direction, an fθ lens 1123 disposed on the rear side of the polygon mirror 1121, A mirror 1124 extending in the X direction is provided.

  The light beam emitted from the light source unit 1111 is converted into linear light that extends in the Z direction, which is the vertical direction, by the linear light generation unit 1112, and enters the spatial light modulator 1113 in which light modulation elements are arranged in the Z direction. . The light beam spatially modulated by the spatial light modulator 1113 is guided to the polygon mirror 1121 while being condensed by the lens 1122 so as to be within the reflecting surface of the polygon mirror 1121 in the Z direction. The rotation axis and each reflecting surface of the polygon mirror 1121 are parallel to the Z direction, and the shape of the polygon mirror 1121 when viewed in plan is a regular hexagon as shown in FIG. Further, as shown in FIG. 3, the polygon mirror 1121 is connected to a motor 1125, and the polygon mirror 1121 deflects the light beam by reflecting the light beam while rotating, and the light beam is horizontal that is perpendicular to the Y direction. The direction is the X direction (corresponding to the main scanning direction of the light beam). An encoder 1126 is attached to the motor 1125, and the angular position of the polygon mirror 1121 is acquired by the encoder 1126.

  As shown in FIG. 3, the light beam that has passed through the fθ lens is reflected by the mirror 1124 from the direction parallel to the XY plane to the direction parallel to the ZX plane, and travels downward to irradiate the drawing surface of the object 9. The Thereby, an image of the light modulation elements arranged in the Y direction is formed on the drawing surface. The irradiation position of the light beam on the object 9 is scanned in the X direction by the rotation of the polygon mirror 1121, and the moving mechanism 12 moves the object 9 relative to the deflecting unit 112 and the irradiation position of the light beam. Are moved in the Y direction (that is, the direction perpendicular to the X direction which is the main scanning direction). At this time, the moving speed in the X direction of the irradiation position (that is, the scanning speed) is made constant by the fθ lens 1123 regardless of the angular position of the reflecting surface of the polygon mirror 1121. As a result of the above operation, a plurality of irradiation positions are scanned by the deflecting unit 112 and the moving mechanism 12 while simultaneously irradiating light modulated at a plurality of positions arranged in the Y direction by the modulated light generation unit 111 and drawn on the object 9. Is done.

  FIG. 4 is a block diagram showing a functional configuration of the drawing apparatus 1. The control unit 13 of the drawing apparatus 1 includes a drawing control unit 131 that controls the head unit 11 and the moving mechanism 12, a calculation unit 132 that performs calculations necessary for drawing, and a storage unit 133 that stores data referred to during the calculation. The drawing control on the object 9 is performed based on the drawing data 71 input from the external storage unit 14 connected to the control unit 13.

  The calculation unit 132 includes a data conversion unit 1321 and a correction table generation unit 1322, and the data conversion unit 1321 applies the drawing data 71 input from the external storage unit 14 to the spatial light modulator 1113 of the modulated light generation unit 111 in each scan. It is converted into input data (hereinafter referred to as “logical drawing data”). The drawing control unit 131 controls the operation of the spatial light modulator 1113 while inputting logical drawing data to the spatial light modulator 1113, thereby performing spatial modulation of the light beam.

  A signal indicating the angular position of the polygon mirror 1121 (see FIG. 3) is input from the encoder 1126 to the drawing control unit 131, and the drawing control unit 131 controls the moving mechanism 12 in synchronization with the main scanning of the light beam. As a result, the object 9 is moved in the Y direction, which is the sub-scanning direction. In the present embodiment, the control unit 13 is realized by software on a computer. However, the control unit 13 may be realized by hardware. For example, the control unit 13 includes a GPU (Graphic Processing Unit) that performs image processing. A board on which the integrated circuit is mounted may be used.

  FIG. 5 is a diagram showing a flow of generating a table (hereinafter referred to as “correction table”) indicating the correspondence between the image indicated by the logical drawing data and the image drawn on the object 9 as a drawing preparation stage. . First, a test object is arranged on the moving mechanism 12 in place of the object 9, and test pattern data 72 used to create the correction table 74 is converted from the external storage unit 14 as shown in FIGS. The light is input to the spatial light modulator 1113 of the modulated light generation unit 111 via the unit 1321 and the drawing control unit 131. At this time, the data conversion unit 1321 converts the format of the test pattern data 72 so that the resolution is suitable for the spatial light modulator 1113 without changing the shape of the test pattern indicated by the test pattern data 72.

  FIG. 6 is a diagram illustrating a logical test pattern 81 indicated by the test pattern data 72. The logical test pattern 81 is based on a pixel array (hereinafter referred to as “logical pixel array”) of data input to the spatial light modulator 1113. This is the test pattern to be expressed. The x-direction and the y-direction perpendicular to the x-direction of the coordinate system representing the logical pixel array (hereinafter referred to as “logical coordinate system”, and the coordinates represented thereby are called “logical coordinates”) are the main scanning directions. The X direction substantially corresponds to the Y direction that is the sub-scanning direction. Actually, the x direction and the y direction do not necessarily match the X direction and the Y direction due to distortion caused by the optical system. The logical test pattern 81 is a grid-like rectangle in which straight lines parallel to the x direction and the y direction are arranged at equal intervals, and is drawn by one main scanning of the light beam. FIG. 6 shows the logic test pattern 81 with the aspect ratio changed and the number of lines reduced.

  When data indicating the logical test pattern 81 is generated by the data conversion unit 1321, the drawing control unit 131 controls the spatial light modulator 1113 based on this data and a signal from the encoder 1126, whereby the light beam is modulated. The test pattern is drawn by scanning the irradiation position of the light beam on the test object. A test pattern is drawn on each reflection surface of the polygon mirror 1121, and a test pattern corresponding to each reflection surface is drawn (FIG. 5: Step S11). Each drawn test pattern is captured by the camera 2 (see FIG. 1) and acquired as image data (step S12).

  FIG. 7 is a diagram showing a drawn test pattern image 91 (hereinafter referred to as “test pattern image 91”), with distortion being emphasized. The X direction, which is the main scanning direction, and the Y direction, which is the sub-scanning direction, are each referred to as a coordinate system on the drawing surface of the test object (hereinafter referred to as “target coordinate system”). .) The test pattern image 91 is, for example, an image distorted in a barrel shape as shown in FIG. 7 due to the influence of the optical system such as the aberration of the lens and the tilt and distortion of the reflection surface of the polygon mirror 1121. In particular, the closer to the periphery of the test pattern image 91, the larger the deviation between the logical coordinates and the target coordinates. The distorted shape can be a pincushion or other shape.

  As shown in FIG. 4, the test pattern image 91 captured by the camera 2 is stored as test pattern image data 73 in the storage unit 133 of the control unit 13. 8 and 9 are diagrams showing the outlines of the test pattern images 91 corresponding to all the reflecting surfaces, and the test pattern images are denoted by reference numerals 91a to 91f. As shown in FIG. 8, in the test pattern images 91a to 91f, the position and the inclination are slightly shifted due to the influence of the inherent tilt of the reflecting surface (the tilt of the reflecting surface with respect to the rotation axis of the polygon mirror 1121).

  Next, the correction table generation unit 1322 of the calculation unit 132 uses a region 911 (hereinafter referred to as “the same” for all test pattern images indicated by parallel diagonal lines in the superimposed test pattern images 91a to 91f illustrated in FIG. A region 92 (hereinafter referred to as “target drawing region 92”) to be drawn by one scan of the actual light beam irradiation position is set in the common region 911 ”) (step S13). . The target drawing area 92 is a rectangular area formed by a side parallel to the X direction and a side parallel to the Y direction. The target drawing area 92 depends on the reflection surface of the polygon mirror 1121 by being provided in the common area 911. Thus, the region can be drawn by scanning the irradiation position of the light beam. In addition, a pixel array that represents an image that is arranged in the XY direction and is rendered in the target drawing area 92 is referred to as a “target pixel array”, and each pixel is referred to as a “target pixel”. In FIG. 9, the square representing the target pixel is exaggerated.

  FIG. 10 is a diagram showing one test pattern image 91a and the target drawing region 92 in an overlapping manner, and FIG. 11 is a diagram showing another test pattern image 91b and the target drawing region 92 in an overlapping manner. A broken line parallel to the Y direction is shown in the target drawing area 92 for reference. Although the position of the target drawing area 92 is constant in the target coordinate system on the test object as shown in FIG. 9, the test pattern image depends on which reflecting surface of the polygon mirror 1121 reflects the light beam when drawing. The relative position with respect to 91 changes. 10, the position of the target drawing area 92 in the test pattern image 91a is relatively biased downward in FIG. 10, and in FIG. 11, the position of the target drawing area 92 in the test pattern image 91b is in FIG. It is relatively biased upward. Further, the grid points of the test pattern image 91 indicate the grid points of the logical test pattern in the logical coordinate system represented in the xy direction shown in FIG. 6, and the target drawing area 92 is shown in FIGS. Depending on the reflection surface, different logical coordinates correspond to one target coordinate.

  When the target drawing area 92 is set, next, the target coordinates of the lattice points of the test pattern image 91a are acquired, and the correspondence between the target coordinates and the logical coordinates at the lattice points is obtained. Further, target coordinates of each vertex of each target pixel that is a square are acquired (step S14). Then, the logical coordinates of the vertex of the target pixel are obtained based on the acquired target coordinates of the lattice point and the target coordinates of the target pixel vertex.

  FIG. 12 shows a target point 611 (that is, one of the vertices of the target pixel) for which logical coordinates are to be obtained and a substantially rectangular lattice element 61 surrounding the target point 611 in the target drawing area 92. . FIG. 13 shows a converted target point 621 corresponding to the target point 611 and a converted target point 621 in the logical coordinate system, and a square lattice element 62 corresponding to the lattice element 61 (hereinafter referred to as “logical lattice element 62”). .). In FIG. 12, reference numerals 612, 613, 614, and 615 are attached clockwise to lattice points surrounding the lattice element 61, and line segments connecting the lattice points are indicated by thin lines attached with reference numerals D1 to D4. Further, reference numerals 616 and 618 are given to the intersections of the straight line L1 passing through the target point 611 and the line segments D1 and D3, and reference numerals 617 and 619 are given to the intersections of the other straight line L2 passing through the target point and the line segments D2 and D4. It is attached.

  When the logical coordinates of the target point 611 are obtained, first, the ratio of the distance from the lattice point 612 to the intersection point 616 and the distance from the intersection point 616 to the lattice point 613 is the distance from the lattice point 615 to the intersection point 618. The internal division ratios s1 and s2 of the intersections 616 and 618 in the straight line L1 and the line segments D1 and D3 that are equal to the ratio with the distance from the intersection point 618 to the lattice point 614 are obtained. Similarly, the ratio of the distance from the lattice point 613 to the intersection point 617 and the distance from the intersection point 617 to the lattice point 614 is the distance from the lattice point 612 to the intersection point 619 and the distance from the intersection point 619 to the lattice point 615. The internal division ratios t1 and t2 of the intersections 617 and 619 in the straight line L2 and the line segments D2 and D4 that are equal to the ratio are obtained.

  Next, as shown in FIG. 13, in the lattice element 62 having lattice points 622, 623, 624, and 625 corresponding to the lattice points 612, 613, 614, and 615 in FIG. An x coordinate of a point 626 that internally divides the connecting line segment E1 into s1 vs. s2, and a y coordinate of a point 629 that internally divides the line segment E4 connecting the grid point 622 and the grid point 625 into t1 vs. t2, These are the logical coordinates of the converted target point 621.

  By the above method, the target coordinates of each vertex of the target pixel forming the target drawing area 92 are converted into logical coordinates, and an area corresponding to the target drawing area 92 in the logical coordinate system (hereinafter referred to as “logical drawing area”). can get. The target drawing area 92 is also converted for all other test pattern images, and the logical drawing areas are acquired individually. Note that the method for obtaining the logical coordinates of the vertices of the target pixel may be other than the method shown in FIGS.

  14 is a diagram showing a logical drawing area 82a corresponding to the target drawing area 92 of the test pattern image 91a shown in FIG. 10 (that is, in the logical coordinate system), and FIG. 15 is a target of the test pattern image 91b shown in FIG. It is a figure which shows the logical drawing area | region 82b corresponding to the drawing area | region 92. FIG. 14 and 15, the logical drawing area is shown with parallel diagonal lines superimposed on the logical test pattern 81, and lines corresponding to the broken reference lines shown in FIGS. 10 and 11 are indicated by broken lines. ing.

  FIG. 16 is an enlarged view showing a part of the logical pixel arrangement, and shows the logical pixels arranged in the x direction and the y direction. In the correction table generation unit 1322 shown in FIG. 4, the target coordinates of the vertices of the target pixel are converted into logical coordinates as described above, and each vertex is added to the logical coordinate system as illustrated with reference numerals 821a to 821d. Be placed. Accordingly, an area 821 (hereinafter referred to as “converted target pixel 821”) surrounded by the vertices 821a to 821d and corresponding to one target pixel is set in the logical drawing area 82. Similarly, the vertices of all other target pixels in the target drawing area 92 are converted, and all the converted target pixels 821 are set by connecting these vertices. Since the converted target pixel 821 is distorted with respect to the logical coordinate system, the boundary line of the converted target pixel 821 connecting the vertices crosses the logical pixel. Therefore, the logical pixel on the boundary line depends on which converted target pixel 821 (or outside of the logical drawing area 82) the area having the larger area among the logical pixel areas divided by the boundary line is included. It is determined which pixel to be converted 821 belongs to (or outside the logical drawing area 82). Thus, the converted target pixel 821 can be expressed as a set of logical pixels.

  One logical pixel corresponds to one light modulation element. When the logical pixel indicates ON during main scanning, the corresponding light modulation element is turned ON to perform drawing at the irradiation position, and when OFF is indicated. The light modulation element is turned off and drawing is not performed. At the time of drawing, the light modulation element is controlled by ON / OFF of the logical pixel included in the converted target pixel 821, and the light ON / OFF to the area corresponding to the target pixel arranged in the XY direction on the target object is controlled. OFF is realized.

  In the present embodiment, one side of one target pixel in the target drawing area 92 is 10 μm, there is no distortion due to the optical system, and the xy direction of the logical coordinate system matches the XY direction of the target coordinate system (that is, In the case where the shape and size of the target pixel and the converted target pixel 821 are the same), one side of one logical pixel is 1 μm. That is, in the drawing apparatus 1, the pixel pitch in the target pixel array is designed to be 10 times the pixel pitch in the logical pixel array.

  Actually, since the other coordinate system is distorted with respect to one coordinate system, the ratio of the pixel pitch between the logical pixel and the target pixel is not exactly 1:10, and the converted target pixel 821 is formed. The number of logical pixels to be changed differs for each converted target pixel 821. In other words, the number of logical pixels forming the converted target pixel 821 is about 100, and the size of one side of each logical pixel is about 1 μm.

  When the corrected target pixel 821 to which each logical pixel belongs is specified by the correction table generation unit 1322 (that is, when a correspondence relationship between the target pixel and the logical pixel is obtained), this information is obtained when each target pixel is ON. It is stored in the storage unit 133 as a correction table 74 indicating which logical pixel should be turned on (step S15). Further, the logical drawing area 82 is obtained for the other test pattern images 91b to 91f, and the correction table 74 is similarly generated. Through the above process, the correction table 74 corresponding to each reflecting surface of the polygon mirror 1121 is stored in the storage unit 133 (step S16).

  Since the converted target pixel 821 shown in FIG. 16 is derived from the lattice point indicated by the test pattern image, the process of generating the correction table 74 by obtaining the corresponding positional relationship between the target pixel and the logical pixel is substantially the same. In particular, it can be said that this is realized by comparing the logical test pattern 81 and the test pattern image 91a. The correction table 74 indicating the logical pixel corresponding to the target pixel substantially indicates the relationship between the target coordinate and the logical coordinate in the target pixel array.

  FIG. 17 is a diagram showing a flow of drawing on the object 9 by the drawing apparatus 1. First, a part of drawing data 71 drawn in the first main scan (hereinafter referred to as “target drawing data”) is input to the data conversion unit 1321 from the external storage unit 14 shown in FIG. 4 (step S21). . The target drawing data corresponds to the target drawing area 92 shown in FIG. 9 and indicates a target pixel array in which the number of rows and the number of columns in one main scanning of the light beam are constant.

  The reflection surface of the polygon mirror 1121 (see FIGS. 2 and 3) used for the first main scan is set in advance, and the correction table 74 corresponding to the reflection surface used for the first main scan is selected (step S22). ). The data conversion unit 1321 converts the target drawing data into logical drawing data indicating the logical pixel arrangement in the logical drawing area 82 illustrated in FIGS. 14 and 15 while referring to the selected correction table 74 (that is, The target pixel ON / OFF information is converted into logic pixel ON / OFF information.) The data is stored in the buffer memory in the data converter 1321 (step S23).

  Next, target drawing data used for the second main scanning is read (step S21), and the reflecting surface of the polygon mirror 1121 used for the second main scanning (that is, the reflecting surface next to the first reflecting surface). Is selected (step S22). Then, the data conversion unit 1321 converts the target drawing data into logical drawing data while referring to the correction table 74, and stores it in the buffer memory (step S23). Steps S21 to S23 are repeated until the entire drawing data 71 is converted into logical drawing data (step S24).

  When all the target drawing data is converted into logical drawing data, the moving mechanism 12 shown in FIG. 1 starts moving the target 9 in the Y direction, which is the sub-scanning direction, and starts rotating the polygon mirror 1121. (Step S25). As shown in FIG. 4, when the reflecting surface corresponding to the logical drawing data used for the first main scan reflects the light beam based on the rotational position information of the polygon mirror 1121 sent from the encoder 1126 of the head unit 11. The logical drawing data corresponding to the first main scan is input to the spatial light modulator 1113 of the modulated light generator 111.

  As shown in FIGS. 2 and 3, the light beam emitted from the light source unit 1111 is converted into linear light by the linear light generation unit 1112 and continuously incident on the spatial light modulator 1113, and spatial light modulation is performed. By controlling ON / OFF of each light modulation element based on the logical drawing data input to the device 1113, a spatially modulated light beam is generated. The spatially modulated light beam is irradiated onto the drawing surface of the object 9 while being scanned in the X direction, which is the main scanning direction, by the deflecting unit 112 on the irradiation position of the object 9. The main scanning is performed, and an array of target pixels without distortion is rendered (step S26). In parallel with the drawing in the main scanning direction in step S26, the moving mechanism 12 moves the object 9 relative to the deflecting unit 112, so that the irradiation position of the light beam is moved in the sub scanning direction. The

  When the first main scan is completed, logical drawing data corresponding to the reflection surface of the polygon mirror 1121 used for the next main scan is input to the spatial light modulator 1113. The light beam spatially modulated by the spatial light modulator 1113 scans the irradiation position on the object 9 (an irradiation position adjacent to the irradiation position by the first main scanning in the sub-scanning direction) in the main scanning direction by the deflecting unit 112. While being drawn, the drawing surface of the object 9 is irradiated, and drawing by the second main scanning is performed on the target drawing area 92 adjacent to the target drawing area 92 at the time of the first main scanning (step S26).

  Step S26 is repeated, drawing is performed in the target drawing area 92 arranged without gaps in the sub-scanning direction, and all drawing data 71 is read and drawing is completed (step S27). The movement is stopped (step S28).

  The above drawing operation on the object 9 may be changed as appropriate. For example, when the storage of the logical drawing data in the buffer memory reaches a certain amount before all the target drawing data is converted, the processing after step S25 is performed. An operation may be initiated. In this case, the conversion of the target drawing data shown in steps S21 to S23 into the logical drawing data and the drawing shown in step S26 are performed in parallel.

  As described above, the drawing apparatus 1 refers to the correction table 74 in drawing with a spatially modulated light beam, and converts the target drawing data indicating the target pixel array into logical drawing data that reflects distortion due to the optical system. Thus, it is possible to draw an image with high speed and high accuracy while correcting distortion due to the influence of the optical system. In the present embodiment, of the 1024 light modulation elements arranged in the Z direction, about 800 can be effectively used as the logical drawing region 82 without being affected by the optical system. As described above, since the logical pixel array has a resolution about 10 times that of the target pixel array, the width in the Y direction at the light beam irradiation position corresponds to about 80 target pixels, and drawing is performed at high speed. Is called.

  Further, the correction table 74 is generated for each surface of the polygon mirror 1121 and appropriately selected and referred to, whereby the image distortion due to each surface of the polygon mirror 1121 can be individually corrected. Since the target pixel is a virtual pixel realized by a set of logical pixels, the pixel pitch of the target pixel can be variously changed by regenerating the correction table.

  FIG. 18 is a diagram showing another example of the head portion, and shows the arrangement of the optical elements in an expanded manner as in FIG. 18 is provided with a galvano mirror 1121a in the deflecting unit 112 instead of the polygon mirror 1121 shown in FIG. 3, and the galvano mirror 1121a reciprocates around a central axis parallel to the reflecting surface by a driving unit 1127. Swing to move. Further, the drive unit 1127 outputs a signal that plays the same role as the output from the encoder 1126 in FIG. The other configuration of the drawing apparatus 1 is the same as that shown in FIGS.

  The operation of the drawing apparatus 1 is the same as the case where the polygon mirror 1121 is used except that the deflecting unit 112 has one reflecting surface. That is, a test pattern is drawn on the test object, and a correction table 74 corresponding to one reflecting surface is obtained. An image can be obtained at high speed and with high accuracy while correcting distortion due to the influence of the optical system while referring to the correction table 74. Drawn.

  Note that the drawing by the galvano mirror 1121a may be performed only in one of the reciprocating rotations of the mirror (outward or backward), and the drawing is performed by both reciprocating rotations of the mirror while intermittently moving the object 9. May be performed. In the latter case, the order of the logical drawing data input to the spatial light modulator 1113 in the main scanning direction is alternately inverted.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  For example, the sub-scanning direction in the drawing apparatus 1 may be a direction other than the direction perpendicular to the main scanning direction, and may be inclined as long as it intersects the scanning direction. Specifically, the main scanning direction is slightly inclined from the X direction in order to accurately draw in parallel with the X direction (on the basis of the object) on an object that continuously moves in the sub-scanning direction. It may be.

  Further, the number of irradiation positions arranged in a line where light is irradiated is about 800 in the present embodiment, but may be any number. However, in the present embodiment in which the influence of the optical system can be removed, it is preferably 50 or more. The arrangement direction of the irradiation positions may be inclined with respect to the Y direction as long as the direction intersects the main scanning direction.

  The size of the pixel pitch in the target pixel array relative to the pixel pitch in the logical pixel array is different from 10 times if the logical pixel array has a resolution higher than that of the target pixel array on the assumption that there is no distortion due to the optical system. In practice, it is preferably 1 to 50 times. Further, the target pixel may not be a square pixel but may be a rectangle.

  The correction table 74 directly indicates the relationship between the target coordinates corresponding to the target pixel array (vertex of the target pixel) and the logical coordinates corresponding to the logical pixel, in addition to the set of logical pixels corresponding to the target pixel. There may be. In this case, a set of logical pixels corresponding to the target pixel is obtained with reference to the correction table at the time of drawing, but it is not necessary to regenerate the correction table even if the pixel pitch of the target pixel is changed. Further, the correction table may be in other formats as long as the relationship between the target coordinates corresponding to the target pixel array and the logical coordinates corresponding to the logical pixels is substantially shown.

  The number of reflection surfaces of the polygon mirror 1121 may be other than six, and the correction tables 74 are generated as many as the number of reflection surfaces. Furthermore, an optical element other than a polygon mirror or a galvanometer mirror may be used for the deflecting unit 112, and for example, an AOM (Acoustic Optical Modulator) may be used.

  The spatial modulation of the light beam by the modulated light generation unit 111 is not limited to that by a diffraction grating type light modulation element such as a GLV element or a TIR element. For example, the direction of a minute mirror arranged two-dimensionally is changed. A DMD (Digital Micromirror Device) that performs spatial modulation by changing may be used. Further, multiple irradiation with a plurality of mirrors may be performed at each position on the object. Further, a spatially modulated light beam (that is, a bundle of modulated light beam elements) may be generated by a plurality of semiconductor lasers or light emitting diodes.

  The logical pixel array may have multi-gradation information in addition to the ON / OFF binary information. In this case, the intensity or amount of light applied to the position corresponding to each logical pixel is controlled to multiple gradations.

  The drawing device 1 may be a device that draws a pattern on a semiconductor substrate, a mask, a glass substrate for a display device, or the like in addition to the printed board. In addition, the object is a printing plate or a printing plate film, and distortion correction using the above correction table is applied to a printing apparatus such as a CTP (Computer to Plate), an image setter, or an electrophotographic high-speed printer. Also good.

It is a perspective view which shows a drawing apparatus. It is a top view which shows a head part. It is a side view which shows a head part. It is a figure which shows the function structure of a drawing apparatus. It is a figure which shows the flow of a correction table production | generation. It is a figure which shows a logic test pattern. It is a figure which shows a test pattern image. It is a figure which shows a test pattern image. It is a figure which shows an object drawing area | region. It is a figure which shows an object drawing area | region. It is a figure which shows an object drawing area | region. It is a figure which shows the drawn lattice element. It is a figure which shows a logic lattice element. It is a figure which shows a logic drawing area | region. It is a figure which shows a logic drawing area | region. It is an enlarged view of a logical pixel array. It is a figure which shows the flow of the drawing to a target object. It is a figure which shows the other example of a head part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drawing apparatus 9 Object 12 Moving mechanism 72 Test pattern data 74 Correction table 81 Logical test pattern 91 Test pattern image 92 Target drawing area 111 Modulated light generation part 112 Deflection part 133 Storage part 1111 Light source part 1112 Linear light generation part 1113 Space Optical modulator 1121 Polygon mirror 1121a Galvano mirror 1321 Data converter S11 to S16, S21 to S28 Steps

Claims (12)

A drawing device for drawing an image on an object by light irradiation,
A modulated light generator for generating a spatially modulated light beam;
A deflecting unit that scans an irradiation position of the light beam on the object in a predetermined scanning direction by deflecting the light beam;
A moving mechanism that moves the irradiation position of the light beam in a direction intersecting the scanning direction by moving the object relative to the deflection unit;
A logical pixel array indicated by target coordinates corresponding to a target pixel array set in an area that can be drawn by each scanning of the irradiation position of the light beam, and logical drawing data input to the modulated light generation unit in each scanning A storage unit for storing a correction table indicating a relationship with logical coordinates corresponding to
A data converter that refers to the correction table and converts target drawing data indicating a target pixel array in each scan of the light beam into logical drawing data indicating a logical pixel array having a resolution equal to or higher than the target pixel array; ,
A drawing apparatus comprising: The drawing apparatus according to claim 1,
The deflection unit includes a polygon mirror that deflects the light beam by reflecting the light beam on a plurality of reflecting surfaces while rotating,
The drawing apparatus, wherein the storage unit stores a correction table corresponding to each reflecting surface of the polygon mirror. The drawing apparatus according to claim 2,
The drawing apparatus, wherein the number of rows and the number of columns of the target pixel array drawn on the object by each scan of the irradiation position of the light beam are constant. The drawing apparatus according to claim 1,
The drawing apparatus, wherein the deflection unit includes a galvanometer mirror that deflects the light beam by reflecting the light beam on a reflection surface while swinging. The drawing apparatus according to any one of claims 1 to 4,
A drawing apparatus, wherein modulated light is irradiated to each of a plurality of positions arranged in a line in a direction intersecting the scanning direction by irradiation of the object with the light beam. The drawing apparatus according to claim 5,
The drawing apparatus, wherein the number of the plurality of positions is 50 or more. The drawing apparatus according to claim 5 or 6, wherein
The modulated light generator is
A light source unit;
A spatial light modulator in which a plurality of diffraction grating type light modulation elements are linearly arranged;
An optical system that converts the light from the light source section into linear light having a linear cross section and guides it to the spatial light modulator;
A drawing apparatus comprising: The drawing apparatus according to any one of claims 1 to 7,
The drawing apparatus, wherein a pixel pitch in the target pixel array is 1 to 50 times a pixel pitch in the logical pixel array. A drawing method for drawing an image on an object by light irradiation,
a) generating a spatially modulated light beam by the modulated light generator;
b) scanning the irradiation position of the light beam on the object in a predetermined scanning direction by a deflecting unit that deflects the light beam;
c) In parallel with the steps a) and b), the irradiation position of the light beam is moved in a direction crossing the scanning direction by moving the object relative to the deflection unit. Process,
With
A logical pixel array indicated by target coordinates corresponding to a target pixel array set in an area that can be drawn by each scanning of the irradiation position of the light beam, and logical drawing data input to the modulated light generation unit in each scanning A correction table showing the relationship with the logical coordinates corresponding to is stored in the storage unit,
In the step a), referring to the correction table, the target drawing data indicating the target pixel array in each scan of the light beam is changed to logical drawing data indicating a logical pixel array having a resolution higher than the target pixel array. A drawing method characterized by being converted and inputted to the modulated light generation unit. The drawing method according to claim 9, wherein
Before step a)
d) drawing a test pattern on the test object by scanning the irradiation position of the light beam on the test object while inputting data indicating a logical test pattern to the modulated light generation unit;
e) capturing the test pattern drawn on the test object to obtain a test pattern image;
f) generating the correction table by comparing the logical test pattern and the test pattern image;
A drawing method, further comprising: The drawing method according to claim 9 or 10, wherein
The deflection unit includes a polygon mirror that deflects the light beam by reflecting the light beam on a plurality of reflecting surfaces while rotating,
The drawing method, wherein the storage unit stores a correction table corresponding to each reflecting surface of the polygon mirror. The drawing method according to claim 9 or 10, wherein
The drawing method, wherein the deflection unit includes a galvanometer mirror that deflects the light beam by reflecting the light beam on a reflecting surface while swinging.

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