JP2006267472A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus wherein a drawing position does not deviate by force from a wire harness. <P>SOLUTION: In the image forming apparatus provided with a drawing means for forming an image on a work, a control board to which a harness for image transmission inputting image data is connected and which generates a control signal on the basis of the image data inputted via the harness for image transmission, and a driving board provided adjacently to the drawing means and driving the drawing means on the basis of the control signal inputted from the control board, the control board and the driving board are connected to each other by a flexible board having flexibility. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus in which an image forming position on a workpiece does not shift due to an influence of a wire harness connected to a drawing unit.

  In recent years, a multi-beam exposure that uses a spatial light modulator such as a digital micromirror device (DMD) as a pattern generator to perform image exposure on a member to be exposed by a light beam modulated in accordance with image data. Development of equipment is underway.

  The DMD is a mirror device in which a large number of micromirrors whose reflection surfaces change in response to control signals are two-dimensionally arranged on a semiconductor substrate such as silicon, and are microscopically generated by electrostatic force generated by charges stored in each memory cell. The angle of the reflecting surface of the mirror is changed.

  In a conventional multi-beam exposure apparatus using a DMD, for example, a laser beam emitted from a light source that emits a laser beam is collimated by a lens system, and a plurality of DMD micromirrors arranged at a substantially focal position of the lens system. Using an exposure head that reflects each laser beam and emits each beam from a plurality of beam exit ports, and further collects each beam emitted from the beam exit port of the exposure head with one lens per pixel. A lens system having an optical element such as a lens array forms an image with a reduced spot diameter on the exposure surface of the photosensitive material (exposed member), and performs image exposure with high resolution.

  The multi-beam exposure apparatus modulates (deflects) the laser beam by controlling each of the DMD micromirrors on / off with a drive circuit based on a control signal generated according to image data or the like. The exposed laser beam is irradiated onto the exposure surface (recording surface) for exposure.

  The multi-beam exposure apparatus includes an exposure unit having a plurality of exposure heads. A photosensitive material (photoresist or the like) is disposed on a recording surface and moved relative to the exposure unit, and the DMD of each exposure head is arranged. There is a multi-head exposure apparatus that performs pattern exposure on the photosensitive material by modulating in accordance with image data.

  However, in recent years, as the degree of integration of the substrates has increased, higher resolution has been required, so that the allowable value of the relative position shift of the image corresponding to each exposure head has decreased.

  Furthermore, in the exposure head, since many optical members and mechanism members are used from the light source to the imaging surface, thermal expansion and contraction due to temperature change, and accumulation of changes over time due to long-term use. As a result, there is a problem that the image formed by each exposure head causes a shift that cannot be ignored at the joint, and the image quality is deteriorated.

  Therefore, a method has been proposed in which the position of each beam is detected by a position detection element such as a PSD (position-sensing device) or a quadrant detector, and the deviation between images formed by each beam is corrected ( Patent Document 1).

  However, in a multi-head exposure apparatus including a plurality of exposure heads, the interval between exposure heads is overwhelmingly larger than the interval between adjacent beams, so it is difficult to apply the method described in Patent Document 1. .

  Therefore, from the position information detected by the beam position detection means, the deviation amount calculation means obtains the drawing deviation amount, corrects appropriately according to the detected drawing deviation amount, and performs high-precision drawing to achieve high quality. A multi-head exposure apparatus that can obtain an exposure image of the above has been considered.

  In the multi-head exposure apparatus, a control substrate that outputs a control signal based on image data and a drive substrate that drives a spatial modulation element such as a DMD based on a control signal from the control substrate are provided for each exposure head. It is common to provide it.

In recent years, the amount of image data input to the control substrate of each exposure head has become enormous as it has been required to form a high-density image on a photosensitive material having a large area. Therefore, an image transmission harness connected to the control board and inputting image data tends to become thicker.
Japanese Patent Laid-Open No. 10-31170

  However, a wire harness such as an image transmission harness becomes stiff when thick, but the wire harness is usually connected to the control board in a bent state for the convenience of wiring. Therefore, since the exposure head receives a force for the wire harness to return, the irradiation position of the light beam may be shifted.

  In particular, the exposure head includes a spatial modulation unit that modulates a light beam by a spatial modulation element such as a DMD, and an imaging optical system that forms an image of the light beam modulated by the spatial modulation unit on a workpiece, In addition, when the imaging optical system includes a microlens array that images each of the light beams modulated by the spatial modulation element onto a workpiece such as a photosensitive material, the spatial modulation unit is generated by the force from the wire harness. There is a possibility that a relative position between the optical system and the imaging optical system is shifted and a desired optical performance cannot be obtained.

  The present invention has been made to solve the above problems, and even when the wire harness connected to the drawing means such as an exposure head is thick and firm, drawing is performed with the force from the wire harness. An object of the present invention is to provide an image forming apparatus whose position does not change.

  According to the first aspect of the present invention, a drawing means for forming an image on a work and an image transmission harness for inputting image data are connected, and a control signal is transmitted based on the image data input through the image transmission harness. A control board that is generated, and a drive board that is provided adjacent to the drawing means and drives the drawing means based on a control signal input from the control board, and the control board and the drive board are flexible The present invention relates to an image forming apparatus characterized by being connected by a flexible substrate having a property.

  In the image forming apparatus, since the control board and the drive board are connected by a flexible board, the external force transmitted from the image transmission harness to the control board is cut off by the flexible board, and almost transmitted to the drive board. Not.

  Therefore, even if the image transmission harness is thick and stiff, the position of the drawing means does not go wrong due to the force from the image transmission harness.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the drawing unit is an exposure head that forms an image on a work by modulating a light beam by a spatial modulation element according to image data. The drive board drives the spatial modulation element based on a control signal input from the control board.

  Since the exposure head forms an image with pixels that irradiate the workpiece with a light beam, if the position of the exposure head is shifted due to some external force, the position of the pixel is also shifted, and a highly accurate image cannot be obtained.

  This problem becomes a serious problem when it is required to form a fine image on the workpiece.

  In the image forming apparatus, the external force from the image transmission harness is transmitted to the control substrate, but is blocked by the flexible substrate, so that the external force is not transmitted to the drive substrate or the exposure head.

  Therefore, even when it is required to form a fine image on the workpiece, a highly accurate image can be obtained.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the exposure head modulates a light beam by the spatial modulation element, and the light beam modulated by the spatial modulation unit And an imaging optical system that forms an image on a workpiece.

  In an image forming apparatus in which the exposure head is divided into a spatial modulation unit and an imaging optical system, if the image transmission harness connected to the control board is stiff, the force from the image transmission harness As a result, the relative position between the spatial modulation unit and the imaging optical system may shift, and the image may not be correctly formed on the workpiece.

  However, in the image forming apparatus, since the control board and the drive board are connected by the flexible board, the force from the image transmission harness is absorbed by the flexible board and reaches the spatial modulation unit and the imaging optical system. Absent.

  Therefore, the relative position between the spatial modulation unit and the imaging optical system does not go wrong.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the exposure apparatus includes a plurality of exposure heads, and the plurality of exposure heads are arranged in the x direction to form an exposure unit. Each of the exposure heads is provided with the control substrate and the drive substrate, and during the image formation, the workpiece is moved along the y direction substantially perpendicular to the x direction with respect to the exposure unit. The present invention relates to a device provided with a workpiece moving means for relative movement.

  In the image forming apparatus, by controlling on-off of pixels in each exposure head so that two adjacent images are connected to each other, an image can be formed with high accuracy even on a large-area work.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the third or fourth aspect, the imaging optical system forms an image of each of the light beams modulated by the spatial modulation element on a work. It is related with what comprises.

  In the image forming apparatus, the pixels modulated by the spatial modulation unit are each imaged on the work by the microlens array, so that an image formed by turning the pixels on and off by the spatial modulation unit is imaged optically. Even when an image is enlarged at a high magnification and projected onto a work in the system, the sharpness of the image does not deteriorate.

  The invention according to claim 6 is the image forming apparatus according to any one of claims 1 to 5, wherein the image transmission harness is connected to the control board in the vicinity of the control board. It is related to what extends along.

  In the image forming apparatus, the image transmission harness extends in the vicinity of the control board along the direction connected to the control board. Therefore, when the image transmission harness is thick and has a low waist, However, the control board does not receive a strong force from the image transmission harness. Therefore, since the force from the image transmission harness is not transmitted to the drawing means via the control board, the flexible board, and the drive board, a more accurate image can be formed on the workpiece.

  A seventh aspect of the present invention relates to the image forming apparatus according to any one of the first to sixth aspects, further comprising a support member that supports at least one of the control board and the image transmission harness.

  In the image forming apparatus, since at least one of the control board and the image transmission harness is supported by a support member, the force exerted from the image transmission harness toward the control board can be further reduced.

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the fifth to seventh aspects, the control boards are connected by a communication cable, and the communication cable is connected to the control board. In the vicinity, it relates to the one extending along the direction connected to the control board.

  In an image forming apparatus having a plurality of exposure heads, it is common to provide a control substrate for each exposure head. In such an image forming apparatus, it is common to connect control boards with a communication cable so that image data and the like can be exchanged with each other.

  In the image forming apparatus, the communication cable is formed so as to extend along the direction connected to the control board at least in the vicinity of the control board. It can be made extremely small.

  According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the second to eighth aspects, the angle of the reflection surface of the spatial modulation element is changed according to a drive signal from a drive substrate. The present invention relates to a digital micromirror device in which a group of reflecting mirrors are two-dimensionally arranged.

  According to the DMD, all the pixels are formed as minute dots, and the image forming apparatus can form an image with high image quality even when the work has a large area.

  As described above, according to the present invention, even when the wire harness connected to the drawing means is thick and strong, the image where the drawing position is not distorted due to the influence of the waist of the wire harness. A forming apparatus is provided.

  An exposure apparatus that is an example of the image forming apparatus of the present invention will be described below.

  As shown in FIGS. 1-3, the exposure apparatus 100 which concerns on Embodiment 1 is a flat bed type.

  The exposure apparatus 100 is configured such that each part is accommodated in a rectangular frame 12 formed by assembling rod-shaped square pipes into a frame shape. A panel (not shown) is attached to the frame body 12 to block the inside and outside.

  The frame body 12 includes a tall housing portion 12A and a stage portion 12B provided so as to protrude from one side surface of the housing portion 12A.

  The stage portion 12B has an upper surface lower than the housing portion 12A, and is disposed so as to have a substantially waist height when an operator stands in front of the stage portion 12B.

  An opening / closing lid 14 is provided on the upper surface of the stage portion 12B. A hinge (not shown) is attached to one side of the opening / closing lid 14 on the housing 12A side, and opens and closes around this one side.

  An exposure stage 16 corresponding to the stage of the present invention can be exposed on the upper surface of the stage portion 12B with the opening / closing lid 14 opened.

  As shown in FIG. 4, a leg portion 16 </ b> A having a substantially U-shaped cross section is attached to the lower surface of the exposure stage 16. The leg portions 16A support the exposure stage 16 slidably with respect to the surface plate 18 extending from the stage portion 12B to the housing portion 12A, and are parallel to each other and in the longitudinal direction of the surface plate 18. Are supported via a pair of slide rails 20 disposed along the rails. Therefore, the exposure stage 16 moves along the y direction on the slide rail 20 with almost no frictional resistance.

  The photosensitive material 22 which is an example of the workpiece of the present invention is placed on the photosensitive material placement surface 17 in the exposure stage 16. The photosensitive material mounting surface 17 is provided with a plurality of grooves (not shown) so that the inside of the grooves can be made negative pressure by a vacuum pump or the like. By applying a negative pressure in the groove using a vacuum pump or the like, the photosensitive material 22 is brought into close contact with the photosensitive material placement surface 17 and is prevented from moving during mark measurement and exposure.

  As shown in FIG. 1 to FIG. 3, one end of the surface plate 18 in the longitudinal direction reaches the stage portion 12 </ b> B, and the operator places the photosensitive material 22 on the exposure stage 16 with the exposure stage 16 positioned at this position. Can be placed or removed.

  The stage portion 12B is provided with an infrared thermometer 19 for measuring the temperature of the photosensitive material 22 immediately after being placed on the exposure stage 16 located at one end portion of the surface plate 18 in the longitudinal direction. Note that the infrared thermometer 19 may measure the actual temperature of the exposure stage 16. The infrared thermometer 19 corresponds to the workpiece temperature measuring means in the present invention.

  The surface plate 18 is supported by a gantry 24 that is firmly fixed to a square pipe that constitutes the casing 12A, and serves as a reference for the movement locus of the exposure stage 16.

  Between a pair of slide rails 20 arranged along the longitudinal direction of the surface plate 18, a linear motor unit 26, which is a linear drive source applying the driving force of the stepping motor, is arranged. Yes.

  Since the linear motor unit 26 is driven in the same manner as a stepping motor, the exposure stage 16 according to the first embodiment has high accuracy by electrical control such as constant speed, positioning accuracy, torque fluctuation at start and stop, and the like. High drive control is possible.

  An exposure unit 28 is disposed at a substantially middle position of the movement locus on the surface plate 18 in the exposure stage 16, and a camera unit 32 is disposed adjacent to the exposure unit 28.

  The exposure unit 28 and the camera unit 32 are housed in a chamber 46 in order to avoid dimensional changes due to temperature changes. The interior of the chamber 46 is adjusted to a constant temperature by a temperature control unit 50 connected via a duct 48.

  The exposure apparatus 100 further includes a computer 10 that controls the whole and inputs image data. The computer 10 includes a keyboard 10A, a display 10B, and an arithmetic storage unit 10C.

  The exposure unit 28 includes eight exposure heads 280 arranged in two rows along the width direction of the surface plate 18, that is, the x direction, and a digit-shaped exposure unit base 281 to which the exposure head 280 is mounted. Yes. As shown in FIG. 1, the exposure unit base 281 is arranged so as to be spanned between a pair of support columns 30 erected on the outer sides of both end portions in the width direction of the surface plate 18. A passing gate is formed.

  The exposure unit 28 irradiates the photosensitive material 22 on the exposure stage 16 with a plurality of light beams from each exposure head 280 at a predetermined timing while moving the exposure stage 16 at a constant speed. Exposure.

  As shown in FIGS. 7 to 9, the exposure head 280 includes a DMD unit 282 provided at the top, a first imaging optical unit 284 provided below the DMD unit 282, and a first imaging optical unit 284. And a second imaging optical unit 286 provided below. Between the first imaging optical unit 284 and the second imaging optical unit 286, there is provided a microlens array 285 for imaging the pixels turned on by the DMD unit on the photosensitive material 22. The DMD unit 282 corresponds to the spatial modulation unit in the present invention, and the first imaging optical unit 284, the second imaging optical unit 286, and the microlens array 285 correspond to the imaging optical system in the present invention.

  A DMD is accommodated in the DMD unit 282, and a DMD driving substrate 290 for driving the DMD is provided at the top. Above the DMD unit 282, there is further provided a control board 292 for inputting image data from the computer 10 and inputting a control signal to the DMD driving board 290 in each exposure head 280 based on the inputted image data. ing. The control board 292 is connected to the DMD driving board 290 via the flexible board 294. The DMD drive substrate 290 corresponds to the drive substrate of the present invention. An image transmission harness 296 for inputting image data from the computer 10 is connected to the control board 292. The image transmission harness 296 extends in the direction connected to the control board 292 in the vicinity of the control board 292. The support plate 291A that supports the control board 292 has a folded portion 291B as shown in FIGS. 7 and 9, and is screwed to the frame 13A (support member) at the folded portion 291B. Further, the image transmission harness 296 is fixed to the frame 13B (support member) by a stopper 295. The frame 13A and the frame 13B are fixed to the exposure unit base 281, for example.

  The DMD unit 282 is further connected with an optical fiber 283 for introducing laser light from a laser light source in a light source unit provided at a location that does not hinder the movement of the exposure stage 16 in the housing portion 12A. An exhaust heat duct 287 for sending cooling air to the head 280 is connected.

  In each exposure head 280, the incident light beam guided by the optical fiber 283 is controlled in units of pixels by the DMD in the DMD unit 282, and the photosensitive material 22 is exposed to the pixel pattern. In the exposure apparatus 100 according to Embodiment 1, a plurality of pixels are overlapped to express the density of one pixel.

  As shown in FIG. 6B, the exposure heads 280 are arranged in an approximate matrix of m rows and n columns (for example, 2 rows and 4 columns). The exposure stage 16 is arranged in a direction perpendicular to the moving direction of the exposure stage 16, that is, the scanning direction b. In the exposure apparatus 100 according to the first embodiment, the number of exposure heads 280 is 4 × 2 = 8 in relation to the width of the photosensitive material 22. As shown in FIGS. 1 to 3 and FIG. 5, the eight exposure heads 280 are arranged in a staggered manner.

  An exposure area 28B by one exposure head 280 has a rectangular shape with a short side in the scanning direction b, and is inclined at a predetermined inclination angle with respect to the scanning direction. Therefore, when the exposure stage 16 moves, a strip-shaped exposed region is formed in the photosensitive material 22 for each exposure head 280 as shown in FIG.

  As shown in FIG. 10, in one exposure head 280, the exposed region 28B is formed by 20 pixels that are two-dimensionally arranged (for example, 4 × 5).

  Since the 20 pixels are inclined with respect to the scanning direction, the pixels in one column pass between two adjacent pixels in the column located further downstream in the scanning direction. Therefore, the substantial pitch between pixels can be reduced, and high resolution can be achieved.

  The exposure process on the photosensitive material 22 positioned on the exposure stage 16 is not performed when the exposure stage 16 moves on the slide rail 20 toward the back of the housing 12A (outward path), but as described above. First, it is executed when it reaches the back of the housing 12A and returns to the stage 12B (return path).

  That is, the forward path is a movement for obtaining position information of the photosensitive material 22 on the exposure stage 16, and the position information is obtained by imaging the photosensitive material 22 with the camera unit 32.

  As described above, since the control board 292 is connected to the DMD drive board 290 fixed to the DMD unit 282 via the flexible board 294, even if the image transmission harness 296 is strong, The force from the image transmission harness 296 is absorbed by the flexible substrate 294 and is not transmitted to the exposure head 280 itself.

  Further, since the image transmission harness 296 extends in the direction connected to the control board 292 in the vicinity of the control board 292, the force itself applied from the image transmission harness 296 to the control board 292 is very small.

  Therefore, the exposure unit 28 can expose the photosensitive material 22 with particularly high accuracy.

  The present invention can be preferably applied to an image forming apparatus including a plurality of exposure heads.

FIG. 1 is a perspective view illustrating an outline of the image forming apparatus according to the first embodiment. FIG. 2 is a side view schematically illustrating the image forming apparatus according to the first embodiment. FIG. 3 is a plan view schematically showing the image forming apparatus according to the first embodiment. FIG. 4 is a perspective view illustrating a configuration of a stage included in the image forming apparatus. FIG. 5 is a perspective view showing a configuration of an exposure unit provided in the image forming apparatus. FIG. 6 is a plan view showing an exposure area by an exposure unit provided in the image forming apparatus and a plan view showing an array pattern of the head assembly. FIG. 7 is a partial cross-sectional view showing details of the configuration of the exposure head constituting the exposure unit. FIG. 8 is a plan view showing the configuration of the top of the exposure head in the exposure unit. FIG. 9 is a perspective view showing the configuration of the top of one exposure head. FIG. 10 is a plan view showing an arrangement state of each dot pattern of the head assembly provided in the exposure unit provided in the image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Computer 10A Keyboard 10B Display 10C Operation memory | storage part 12 Frame 12A Case part 12B Stage part 14 Opening / closing lid 16 Exposure stage 16A Leg part 17 Photosensitive material mounting surface 18 Surface plate 19 Infrared thermometer 20 Slide rail 22 Photosensitive material 24 Base 26 Linear motor unit 28 Exposure unit 30 Support column 32 Camera unit 46 Chamber 48 Duct 50 Temperature control unit 100 Exposure device 280 Exposure head 281 Exposure unit base 282 DMD unit 283 Optical fiber 284 Imaging optical unit 285 Micro lens array 286 Imaging optical Unit 287 Waste heat duct 290 DMD drive board 292 Control board 294 Flexible board 296 Image transmission harness

Claims (9)

Drawing means for forming an image on the workpiece;
A control board that is connected to an image transmission harness for inputting image data and generates a control signal based on the image data input through the image transmission harness;
A drive board provided adjacent to the drawing means and driving the drawing means based on a control signal input from the control board;
The image forming apparatus, wherein the control board and the driving board are connected by a flexible board having flexibility. The drawing means is an exposure head that forms an image on a work by modulating a light beam by a spatial modulation element according to image data,
The image forming apparatus according to claim 1, wherein the driving substrate drives the spatial modulation element based on a control signal input from the control substrate.   3. The exposure head according to claim 2, comprising: a spatial modulation unit that modulates a light beam by the spatial modulation element; and an imaging optical system that forms an image of the light beam modulated by the spatial modulation unit on a workpiece. Image forming apparatus. Have multiple exposure heads,
The plurality of exposure heads are arranged in the x direction to form an exposure unit,
The control substrate and the drive substrate are provided for each of the exposure heads,
4. The image forming apparatus according to claim 2, further comprising a workpiece moving unit configured to relatively move the workpiece along a y direction substantially perpendicular to the x direction with respect to the exposure unit during image formation. .   5. The image forming apparatus according to claim 3, wherein the imaging optical system includes a microlens array that images each of the light beams modulated by the spatial modulation element onto a workpiece.   The image forming apparatus according to claim 1, wherein the image transmission harness extends in a vicinity of the control board along a direction connected to the control board.   The image forming apparatus according to claim 1, further comprising a support member that supports at least one of the control board and the image transmission harness.   The control boards are connected to each other by a communication cable, and the communication cable extends in a direction connected to the control board in the vicinity of the control board. The image forming apparatus according to claim 1.   9. The spatial modulation element is a digital micromirror device in which a group of reflecting mirrors whose angles of reflecting surfaces are changed according to a driving signal from a driving substrate are arranged two-dimensionally. The image forming apparatus according to any one of the above.

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