JP2007101730A - Image exposure device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image of high picture quality by exposing a photosensitive material without being affected by disturbance vibration. <P>SOLUTION: When at least one of displacement sensors 192, 194, 106 detects displacement by disturbance vibration, a microlens array driving device moves a microlens array 55 in parallel to the direction to compensate a shift of an exposure position by the disturbance vibration. Further, a light-transmitting plate driving device simultaneously rotates a light-transmitting plate while changing an angle between the light-transmitting plate and an exposure plane to the direction to compensate a shift in the exposure position by the disturbance vibration. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image exposure apparatus, and more particularly to an image exposure apparatus that exposes a photosensitive material by forming an image of light modulated by a spatial light modulator on a photosensitive material.

  2. Description of the Related Art Conventionally, there has been known an image exposure apparatus that passes light modulated by a spatial light modulation element through an imaging optical system, forms an image of this light on a predetermined photosensitive material, and exposes the photosensitive material. This type of image exposure apparatus basically irradiates light to a spatial light modulation element in which a plurality of pixel portions that modulate irradiated light according to a control signal are arranged in parallel, and the spatial light modulation element. A light source and an imaging optical system that forms an image of light modulated by the spatial light modulation element on a photosensitive material.

  In this type of image exposure apparatus, for example, a DMD (digital micromirror device) can be suitably used as the spatial light modulation element. The DMD is a mirror device in which a number of rectangular micromirrors that change the angle of the reflecting surface in accordance with a control signal are two-dimensionally arranged on a semiconductor substrate such as silicon. The micromirror functions as a reflective pixel portion.

  In the image exposure apparatus as described above, there is often a demand for enlarging an image projected on a photosensitive material, and in that case, an enlarged imaging optical system is used as an imaging optical system. In doing so, simply passing the light that has passed through the spatial light modulation element through the magnification imaging optical system expands the luminous flux from each pixel portion of the spatial light modulation element, and the pixel size in the projected image is reduced. The image becomes larger and the sharpness of the image decreases.

  Therefore, the first imaging optical system is arranged on the optical path of the light modulated by the spatial light modulation element, and microlenses corresponding to the light beams of the respective pixel portions of the spatial light modulation element that have passed through the imaging optical system are provided. A second imaging optical system in which a microlens array arranged in an array is arranged, and an image of the modulated light is formed on a photosensitive material or a screen in the optical path of the light that has passed through the microlens array. It is considered that a system is arranged and an image is enlarged and projected by the first and second imaging optical systems. In this configuration, the size of the image projected on the photosensitive material and the screen is enlarged, while the light from each pixel portion of the spatial light modulator is condensed by each microlens of the microlens array. Since the pixel size (spot size) in the image is reduced and kept small, the sharpness of the image can be kept high.

  Patent Document 1 shows an example of an image exposure apparatus using DMD as a spatial light modulation element and combining it with a microlens array.

In Patent Document 2, an aperture array (aperture plate) having apertures (openings) corresponding to the microlenses of the microlens array is arranged on the rear side of the microlens array in the same type of image exposure apparatus. A configuration is shown in which only the light passing through the microlens passes through the aperture. In this configuration, light from adjacent microlenses that do not correspond to each aperture of the aperture plate is prevented from entering, so that stray light can be prevented from entering the adjacent pixels. Even when the DMD pixel (micromirror) is turned off so that light is not irradiated onto the exposure surface, a slight amount of light may be incident on the exposure surface. As a result, the amount of light on the exposure surface when the DMD pixel is in the off state can be reduced.
JP 2001-305663 A JP 2004-122470 A

  In the conventional image exposure apparatus in which a spatial light modulation element having a reflective pixel portion, a microlens array, and an imaging optical system are combined as in the DMD described above, pixels such as the micromirrors are formed by the imaging optical system. An image of the portion is formed, and each microlens of the microlens array is positioned in the vicinity of the image forming position.

  The image exposure apparatus having such a configuration exposes the photosensitive material with a beam of about 3 μm. However, when disturbance vibration is applied, there is a problem that the relative position between the exposure head and the stage holding the photosensitive material is shifted by about 1 to 2 μm, and a correct image cannot be formed on the photosensitive material.

  In order to deal with such a problem, it is conceivable to correct the image data obtained by exposure with software. However, the process of correcting by software is complicated, and the processing time cannot be reduced for high tact.

  The present invention has been proposed in order to solve the above-described problems, and provides an image exposure apparatus that can expose a photosensitive material and obtain a high-quality image without being affected by disturbance vibration. Objective.

  The image exposure apparatus of the present invention includes a spatial light modulation element that modulates irradiated light at each pixel unit arranged in a two-dimensional manner, a light source that irradiates light to the spatial light modulation element, and the spatial light modulation A first optical system that focuses the light that has passed through the element to form an image of the pixel unit, and a plurality of light beams that have passed through the first optical system are arranged in a plurality of two-dimensionally with each microlens. A microlens array that forms an image on a photosensitive material, a misalignment detection unit that detects a relative misalignment between the photosensitive material and light from the microlens array caused by disturbance vibration, and detection by the misregistration detection unit And a microlens array moving means for moving the microlens array based on the positional deviation.

  When disturbance vibration occurs, the relative position between the exposure side having the light source and the optical system and the photosensitive material shifts, and the positional deviation of the light on the photosensitive material occurs. Therefore, the image exposure apparatus is based on a positional deviation detection unit that detects a relative positional deviation between the photosensitive material caused by disturbance vibration and the light from the microlens array, and a positional deviation detected by the positional deviation detection unit. By providing the microlens array moving means for moving the microlens array, it is possible to obtain a high-quality image by exposing the photosensitive material without being affected by disturbance vibration.

  The image exposure apparatus according to the present invention can obtain a high-quality image by exposing a photosensitive material without being affected by disturbance vibration.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an image exposure apparatus according to a first embodiment of the present invention will be described.
(Configuration of image exposure apparatus)
As shown in FIG. 1, the image exposure apparatus includes a flat plate-like moving stage 152 that holds a sheet-like photosensitive material 150 on the surface thereof. Two guides 158 extending along the stage moving direction are installed on the upper surface of the thick plate-like installation table 156 supported by the four legs 154. The stage 152 is arranged so that the longitudinal direction thereof faces the stage moving direction, and is supported by a guide 158 so as to be reciprocally movable. The image exposure apparatus is provided with a stage driving device 304 (see FIG. 15), which will be described later, that drives a stage 152 as sub-scanning means along a guide 158.

In the center of the installation table 156, the U-shaped gate 1 extends across the moving path of the stage 152.
60 is provided. Each of the ends of the U-shaped gate 160 is fixed to both side surfaces of the installation table 156. A scanner 162 is provided on one side of the gate 160, and a plurality of (for example, two) sensors 164 for detecting the front and rear ends of the photosensitive material 150 are provided on the other side. The scanner 162 and the sensor 164 are respectively attached to the gate 160 and fixedly arranged above the moving path of the stage 152. The scanner 162 and the sensor 164 are connected to a controller (not shown) that controls them.

As shown in FIGS. 2 and 3B, the scanner 162 includes a plurality of (for example, 14) exposure heads 166 arranged in an approximately matrix of m rows and n columns (for example, 3 rows and 5 columns). . In this example, four exposure heads 166 are arranged in the third row in relation to the width of the photosensitive material 150. In addition, when showing each exposure head arranged in the m-th row and the n-th column, it is expressed as an exposure head 166 _mn .

An exposure area 168 by the exposure head 166 has a rectangular shape with a short side in the sub-scanning direction. Therefore, as the stage 152 moves, a strip-shaped exposed area 170 is formed for each exposure head 166 in the photosensitive material 150. In addition, when showing the exposure area by each exposure head arranged in the m-th row and the n-th column, it is expressed as an exposure area 168 _mn .

Further, as shown in FIGS. 3A and 3B, each of the exposure heads in each row arranged in a line so that the strip-shaped exposed regions 170 are arranged in the direction orthogonal to the sub-scanning direction without gaps. These are arranged with a predetermined interval (natural number times the long side of the exposure area, twice in this example) in the arrangement direction. Therefore, can not be exposed portion between the exposure area 168 ₁₁ in the first row and the exposure area 168 _12, it can be exposed by the second row of the exposure area 168 ₂₁ and the exposure area 168 ₃₁ in the third row.

As shown in FIG. 4, each of the exposure heads 166 _{11 to} 166 _mn serves as a spatial light modulator that modulates an incident light beam for each pixel in accordance with image data. A micromirror device (DMD) 50 is provided. The DMD 50 is connected to a controller 302 (see FIG. 15), which will be described later, provided with a data processing unit and a mirror drive control unit. The data processing unit of the controller 302 generates a control signal for driving and controlling each micromirror in the region to be controlled by the DMD 50 for each exposure head 166 based on the input image data. Further, the mirror drive control unit controls the angle of the reflection surface of each micromirror of the DMD 50 for each exposure head 166 based on the control signal generated by the image data processing unit.

  On the light incident side of the DMD 50, a fiber array light source 66 including a laser emitting section in which emission ends (light emitting points) of an optical fiber are arranged in a line along a direction corresponding to the long side direction of the exposure area 168, a fiber A lens system 67 that corrects laser light emitted from the array light source 66 and collects it on the DMD, and a mirror 69 that reflects the laser light transmitted through the lens system 67 toward the DMD 50 are arranged in this order. In FIG. 4, the lens system 67 is schematically shown.

  As shown in detail in FIG. 5, the lens system 67 condenses the condensing lens 71 that condenses the laser light B as illumination light emitted from the fiber array light source 66, and is inserted into the optical path of the light that has passed through the condensing lens 71. The rod-shaped optical integrator 72 (hereinafter referred to as a rod integrator) 72 and an imaging lens 74 disposed in front of the rod integrator 72, that is, on the mirror 69 side. The condensing lens 71, the rod integrator 72, and the imaging lens 74 cause the laser light emitted from the fiber array light source 66 to enter the DMD 50 as a light beam that is close to parallel light and has a uniform beam cross-sectional intensity.

  The laser beam B emitted from the lens system 67 is reflected by the mirror 69 and irradiated to the DMD 50 via a TIR (total reflection) prism 70. In FIG. 4, the TIR prism 70 is omitted.

  Further, on the light reflection side of the DMD 50, an optical system 51 that forms an image of the laser beam B reflected by the DMD 50 on the photosensitive material 150 is disposed. As shown in FIG. 5, the optical system 51 includes a first optical system including lens systems 52 and 54, a microlens array 55, and a light transmission flat plate provided between the lens system 54 and the microlens array 55. 80.

  A photosensitive material 150 is arranged at a condensing position of each microlens 55a of the microlens array 55, and an image condensed by the microlens array 55 is directly exposed to the photosensitive material 150.

  In the present embodiment, each microlens 55 a of the microlens array 55 is arranged at a condensing position by the micromirror 62 and the lens systems 52, 54 that is out of the imaging position of the micromirror 62 by the lens systems 52, 54. Therefore, even if the DMD 50 and the microlens array 55 are slightly misaligned, the light use efficiency and the extinction ratio are kept high.

  The light transmitting flat plate 80 is a flat plate made of, for example, BK7 and having a predetermined thickness. The light transmission flat plate 80 is arranged in parallel to the exposure surface and the surface of the microlens array 55, but the angle between the light transmission flat plate 80 and the exposure surface can be adjusted by a light transmission flat plate driving device described later.

  As shown in FIG. 6, in the DMD 50, on a SRAM cell (memory cell) 60, a large number (for example, 1024 × 768) of micromirrors (micromirrors) 62 constituting pixels (pixels) are arranged in a grid pattern. This is a mirror device. In each pixel, a rectangular micromirror 62 supported by a support column is provided at the top, and a material having high reflectance such as aluminum is deposited on the surface of the micromirror 62. The reflectivity of the micromirror 62 is 90% or more, the size is 13 μm as an example in both the vertical and horizontal directions, and the arrangement pitch is 13.7 μm as an example in both the vertical and horizontal directions. Each micromirror 62 is formed in a concave mirror shape having a light collecting function by a method described later. A silicon gate CMOS SRAM cell 60 manufactured in a normal semiconductor memory manufacturing line is disposed directly below the micromirror 62 via a support including a hinge and a yoke, and the entire structure is monolithic. ing.

  When a digital signal is written in the SRAM cell 60 of the DMD 50, the micromirror 62 supported by the support is tilted in a range of ± α degrees (for example, ± 12 degrees) with respect to the substrate side on which the DMD 50 is disposed with the diagonal line as the center. It is done. FIG. 7A shows a state in which the micromirror 62 is tilted to + α degrees in the on state, and FIG. 7B shows a state in which the micromirror 62 is tilted to −α degrees in the off state. Therefore, by controlling the tilt of the micromirror 62 in each pixel of the DMD 50 according to the image signal as shown in FIG. 6, the laser light B incident on the DMD 50 is reflected in the tilt direction of each micromirror 62. The

  FIG. 6 shows an example of a state in which a part of the DMD 50 is enlarged and the micromirror 62 is controlled to + α degrees or −α degrees. On / off control of each micromirror 62 is performed by the controller 302 connected to the DMD 50. Further, a light absorber (not shown) is arranged in the direction in which the laser beam B reflected by the off-state micromirror 62 travels.

  The microlens array 55 shown in FIG. 5 is formed by two-dimensionally arranging a large number of microlenses 55a corresponding to each pixel of the DMD 50, that is, each micromirror 62. Each microlens 55a is out of the imaging position of the micromirror 62 by the lens systems 52 and 54 at the position where the laser beam B from the corresponding micromirror 62 is incident. It is arranged at the condensing position. In this example, as described later, only 1024 × 256 rows of the 1024 × 768 rows of micromirrors of the DMD 50 are driven, and accordingly, 1024 × 256 rows of microlenses 55a are arranged. The size of the micro lens 55a is 41 μm in both the vertical direction and the horizontal direction. As an example, the microlens 55a has a focal length of 0.23 mm, an NA (numerical aperture) of 0.06, and is made of quartz glass. In the figure, the photosensitive material 150 is sub-scanned in the direction of arrow F.

  Here, it is preferable that the DMD 50 is arranged with a slight inclination so that the short side forms a predetermined angle θ (for example, 0.1 ° to 5 °) with the sub-scanning direction. 8A shows the scanning trajectory of the reflected light image (exposure beam) 53 by each micromirror when the DMD 50 is not tilted, and FIG. 8B shows the scanning trajectory of the exposure beam 53 when the DMD 50 is tilted. Show.

  In the DMD 50, a number of micromirror arrays in which a large number (for example, 1024) of micromirrors are arranged in the longitudinal direction are arranged in a short direction (for example, 756 sets). As shown in FIG. Further, by inclining the DMD 50, the pitch P1 of the scanning trajectory (scanning line) of the exposure beam 53 by each micromirror becomes narrower than the pitch P2 of the scanning line when the DMD 50 is not inclined, and the resolution is greatly improved. Can do. On the other hand, since the tilt angle of the DMD 50 is very small, the scan width W2 when the DMD 50 is tilted and the scan width W1 when the DMD 50 is not tilted are substantially the same.

  Further, the same scanning line is overlapped and exposed (multiple exposure) by different micromirror rows. In this way, by performing multiple exposure, it is possible to control a minute amount of the exposure position and to realize high-definition exposure. Further, joints between a plurality of exposure heads arranged in the main scanning direction can be connected without a step by controlling a very small amount of exposure position.

  Note that the same effect can be obtained by arranging the micromirror rows in a staggered manner by shifting the micromirror rows by a predetermined interval in a direction orthogonal to the sub-scanning direction instead of inclining the DMD 50.

  As shown in FIG. 9A, the fiber array light source 66 includes a plurality of (for example, 14) laser modules 64, and one end of the multimode optical fiber 30 is coupled to each laser module 64. . An optical fiber 31 having the same core diameter as that of the multimode optical fiber 30 and a smaller cladding diameter than the multimode optical fiber 30 is coupled to the other end of the multimode optical fiber 30. As shown in detail in FIG. 9B, seven ends of the multimode optical fiber 31 opposite to the optical fiber 30 are arranged along the main scanning direction orthogonal to the sub-scanning direction, and they are arranged in two rows. Thus, a laser emitting unit 68 is configured.

  As shown in FIG. 9B, the laser emitting portion 68 configured by the end portion of the multimode optical fiber 31 is sandwiched and fixed between two support plates 65 having a flat surface. In addition, a transparent protective plate such as glass is preferably disposed on the light emitting end face of the multimode optical fiber 31 for protection. The light exit end face of the multimode optical fiber 31 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 this example, as shown in FIG. 10, an optical fiber 31 having a length of about 1 to 30 cm and having a small cladding diameter is coaxially coupled to a tip portion on the laser light emission side of a multimode optical fiber 30 having a large cladding diameter. Yes. The optical fibers 30 and 31 are coupled by fusing the incident end face of the optical fiber 31 to the outgoing end face of the optical fiber 30 in a state where the respective core axes coincide. As described above, the diameter of the core 31 a of the optical fiber 31 is the same as the diameter of the core 30 a of the multimode optical fiber 30.

  As the multimode optical fiber 30 and the optical fiber 31, any of a step index type optical fiber, a graded index type optical fiber, and a composite type optical fiber can be applied. For example, a step index type optical fiber manufactured by Mitsubishi Cable Industries, Ltd. can be used. In this example, the multimode optical fiber 30 and the optical fiber 31 are step index type optical fibers, and the multimode optical fiber 30 has a cladding diameter = 125 μm, a core diameter = 50 μm, NA = 0.2, and transmission of the incident end face coating. The ratio is 99.5% or more, and the optical fiber 31 has a cladding diameter = 60 μm, a core diameter = 50 μm, and NA = 0.2.

  However, the cladding diameter of the optical fiber 31 is not limited to 60 μm. The clad diameter of many optical fibers used in conventional fiber light sources is 125 μm. However, the smaller the clad diameter, the deeper the depth of focus. Therefore, the clad diameter of the multimode optical fiber is preferably 80 μm or less, preferably 60 μm or less. Is more preferable. On the other hand, in the case of a single mode optical fiber, the core diameter needs to be at least 3 to 4 μm, and therefore the cladding diameter of the optical fiber 31 is preferably 10 μm or more. In addition, it is preferable from the viewpoint of coupling efficiency that the core diameter of the optical fiber 30 and the core diameter of the optical fiber 31 are matched.

  In the present invention, it is not always necessary to use the two optical fibers 30 and 31 having different clad diameters fused as described above (so-called different diameter fusion), and an optical fiber having a constant clad diameter ( For example, in the example of FIG. 9a, a plurality of optical fibers 30) may be bundled as they are to form a fiber array light source.

  The laser module 64 is configured by a combined laser light source (fiber light source) shown in FIG. The combined laser light source includes a plurality of (for example, seven) chip-like lateral multimode or single mode GaN-based semiconductor lasers LD1, LD2, LD3, LD4, LD5, LD6, and the like arranged and fixed on the heat block 10. LD 7, collimator lenses 11, 12, 13, 14, 15, 16 and 17 provided corresponding to each of GaN-based semiconductor lasers LD 1 to LD 7, one condenser lens 20, and one multimode light And fiber 30. The number of semiconductor lasers is not limited to seven, and other numbers may be adopted. Further, instead of the seven collimator lenses 11 to 17 as described above, a collimator lens array in which these lenses are integrated can be used.

  The GaN-based semiconductor lasers LD1 to LD7 have substantially the same oscillation wavelength (for example, 405 nm), and all the maximum outputs are also almost the same (for example, about 100 mW for the multimode laser and about 50 mW for the single mode laser). Note that the outputs of the GaN-based semiconductor lasers LD1 to LD7 may be different from each other below the maximum output. Further, as the GaN-based semiconductor lasers LD1 to LD7, lasers that oscillate at wavelengths other than 405 nm in the wavelength range of 350 nm to 450 nm may be used.

  As shown in FIGS. 12 and 13, the above-described combined laser light source is housed in a box-shaped package 40 having an upper opening together with other optical elements. The package 40 includes a package lid 41 created so as to close the opening thereof, and is formed by introducing a sealing gas after the deaeration process and closing the opening of the package 40 with the package lid 41. The combined laser light source is hermetically sealed in a closed space (sealed space).

  A base plate 42 is fixed to the bottom surface of the package 40, and the heat block 10, a condensing lens holder 45 that holds the condensing lens 20, and the multimode optical fiber 30 are disposed on the top surface of the base plate 42. A fiber holder 46 that holds the incident end is attached. The exit end of the multimode optical fiber 30 is drawn out of the package from an opening formed in the wall surface of the package 40.

  A collimator lens holder 44 is attached to the side surface of the heat block 10, and collimator lenses 11 to 17 are held there. An opening is formed in the lateral wall surface of the package 40, and wiring 47 for supplying a driving current to the GaN-based semiconductor lasers LD1 to LD7 is drawn out of the package through the opening.

  In FIG. 13, in order to avoid complication of the drawing, only the GaN semiconductor laser LD7 among the plurality of GaN semiconductor lasers is numbered, and only the collimator lens 17 among the plurality of collimator lenses is numbered. is doing.

  FIG. 14 shows the front shape of the attachment part of the collimator lenses 11-17. Each of the collimator lenses 11 to 17 is formed in a shape obtained by cutting a region including the optical axis of a circular lens having an aspherical surface into a long and narrow plane. This elongated collimator lens can be formed, for example, by molding resin or optical glass. The collimator lenses 11 to 17 are closely arranged in the arrangement direction of the light emitting points so that the length direction is orthogonal to the arrangement direction of the light emitting points of the GaN-based semiconductor lasers LD1 to LD7 (left and right direction in FIG. 14).

  On the other hand, each of the GaN-based semiconductor lasers LD1 to LD7 includes an active layer having a light emission width of 2 μm, and the laser beams B1 to A laser emitting B7 is used. These GaN-based semiconductor lasers LD1 to LD7 are arranged so that the light emitting points are arranged in a line in a direction parallel to the active layer.

  Therefore, in the laser beams B1 to B7 emitted from the respective light emitting points, the direction in which the divergence angle is large coincides with the length direction and the divergence angle is small with respect to the elongated collimator lenses 11 to 17 as described above. Incident light is incident in a state where the direction coincides with the width direction (direction perpendicular to the length direction). That is, the collimator lenses 11 to 17 have a width of 1.1 mm and a length of 4.6 mm, and the horizontal and vertical beam diameters of the laser beams B1 to B7 incident thereon are 0.9 mm and 2. 6 mm. Each of the collimator lenses 11 to 17 has a focal length f1 = 3 mm, NA = 0.6, and a lens arrangement pitch = 1.25 mm.

  The condensing lens 20 is formed by cutting a region including the optical axis of a circular lens having an aspheric surface into a long and narrow shape in parallel planes, and is long in the arrangement direction of the collimator lenses 11 to 17, that is, in a horizontal direction and short in a direction perpendicular thereto. Is formed. The condenser lens 20 has a focal length f2 = 23 mm and NA = 0.2. The condensing lens 20 is also formed by molding resin or optical glass, for example.

  Next, the electrical configuration of the image exposure apparatus of this example will be described with reference to FIG. As shown here, a modulation circuit 301 is connected to the overall control unit 300, and a controller 302 that controls the DMD 50 is connected to the modulation circuit 301. Further, an LD drive circuit 303 that drives the laser module 64 and a stage drive device 304 that drives the stage 152 are connected to the overall control unit 300. The overall control unit 300 further inclines the microlens array driving device 305 that moves the microlens array 55 in a direction parallel to the exposure surface, and the light transmission flat plate 80 that changes the angle formed by the microlens array 55. A light transmission flat plate driving device 306 and displacement sensors 192, 194, 196 for detecting disturbance vibration are connected.

  As shown in FIG. 16, the displacement sensor 192 measures the relative position in the x direction between the photosensitive material 150 and the exposure head. The displacement sensors 194 and 196 measure the relative position in the y direction between the photosensitive material 150 and the exposure head. The displacement sensors 192, 194, and 196 are laser length measuring devices in this embodiment, and are fixed by an unillustrated indicating member so as to be able to move rigidly with the scanner 162.

  The displacement sensor 192 is disposed at a position corresponding to the bar-shaped mirror 193 provided on the side surface parallel to the y direction of the stage 152, and performs position measurement using reflection by the mirror 193. The displacement sensors 194 and 196 perform position measurement using reflections by two mirrors 195 and 197 provided near both ends of the side parallel to the x direction of the stage 152, respectively.

  The displacement sensors 192, 194, and 196 measure the relative position of the exposure head with respect to the photosensitive material 150, and output the measurement information to the overall control unit 300 shown in FIG. The measurement information includes an x-direction position and two y-direction positions.

The overall control unit 300 calculates the x- and y-direction positions of the stage 152 and the attitude of the stage 152 (rotation angle around the z-axis) from the measurement information, and the x- and y-directions of the exposure head with respect to the photosensitive material 150. A relative positional shift is obtained, and shift amounts in the x and y directions for correcting the relative positional shift are calculated. Then, the overall control unit 300 controls the microlens array driving device 305 and / or the light transmissive plate driving device 306 based on the shift amount.
(Operation of image exposure device)
Next, the operation of the image exposure apparatus will be described. In each exposure head 166 of the scanner 162, laser light B1, B2, B3 emitted in a divergent light state from each of the GaN-based semiconductor lasers LD1 to LD7 (see FIG. 11) constituting the combined laser light source of the fiber array light source 66. Each of B4, B5, B6, and B7 is collimated by the corresponding collimator lenses 11-17. The collimated laser beams B <b> 1 to B <b> 7 are collected by the condenser lens 20 and converge on the incident end face of the core 30 a of the multimode optical fiber 30.

  In this example, the collimating lenses 11 to 17 and the condensing lens 20 constitute a condensing optical system, and the condensing optical system and the multimode optical fiber 30 constitute a multiplexing optical system. That is, the laser beams B1 to B7 collected as described above by the condenser lens 20 enter the core 30a of the multimode optical fiber 30 and propagate through the optical fiber to be combined with one laser beam B. The light is emitted from the optical fiber 31 coupled to the output end of the multimode optical fiber 30.

  In each laser module, when the coupling efficiency of the laser beams B1 to B7 to the multimode optical fiber 30 is 0.9 and each output of the GaN-based semiconductor lasers LD1 to LD7 is 50 mW, the light arranged in an array For each of the fibers 31, a combined laser beam B having an output of 315 mW (= 50 mW × 0.9 × 7) can be obtained. Therefore, the entire 14 multi-mode optical fibers 31 can obtain a laser beam B having an output of 4.4 W (= 0.315 W × 14).

  At the time of image exposure, image data corresponding to the exposure pattern is input from the modulation circuit 301 shown in FIG. 15 to the controller 302 of the DMD 50 and temporarily stored in the frame memory. This image data is data representing the density of each pixel constituting the image by binary values (whether or not dots are recorded).

  The stage 152 that has adsorbed the photosensitive material 150 to the surface is moved at a constant speed from the upstream side to the downstream side of the gate 160 along the guide 158 by the stage driving device 304 shown in FIG. When the leading edge of the photosensitive material 150 is detected by the sensor 164 attached to the gate 160 when the stage 152 passes under the gate 160, the image data stored in the frame memory is sequentially read out for each of a plurality of lines. A control signal is generated for each exposure head 166 based on the image data read by the data processing unit. Then, each of the micromirrors of the DMD 50 is controlled on and off for each exposure head 166 based on the generated control signal by the mirror drive control unit.

  When the laser light B is irradiated from the fiber array light source 66 to the DMD 50, the laser light reflected when the micromirror of the DMD 50 is on is imaged on the photosensitive material 150 by the lens system 51. In this manner, the laser light emitted from the fiber array light source 66 is turned on and off for each pixel, and the photosensitive material 150 is exposed in pixel units (exposure area 168) that is approximately the same number as the number of pixels used in the DMD 50. Further, when the photosensitive material 150 is moved at a constant speed together with the stage 152, the photosensitive material 150 is sub-scanned in the direction opposite to the stage moving direction by the scanner 162, and a strip-shaped exposed region 170 is formed for each exposure head 166. It is formed.

  At this time, as shown in FIG. 17A, the light transmitting flat plate 80 is arranged in parallel to the exposure surface. Therefore, the light from the lens system 54 shown in FIG. 5 passes through the light transmission flat plate 80 as it is, and is imaged on the photosensitive material 150 by each microlens 55a of the microlens array 55. However, when disturbance vibration is applied from the outside, a shift occurs between the stage 55 and the optical system, and the exposure position shifts.

  Therefore, when at least one of the displacement sensors 192, 194, and 196 detects displacement due to disturbance vibration, the microlens array driving device 305 illustrated in FIG. 15 detects the exposure position due to the disturbance vibration as illustrated in FIG. The microlens array 55 is translated in a direction that cancels the shift. Thereby, since the deviation of the exposure position can be corrected, a high-quality image can be formed without being affected by disturbance vibration.

  At this time, as shown in FIG. 17B, the light transmission flat plate driving device 306 further changes the angle formed between the light transmission flat plate 80 and the exposure surface in a direction to cancel the deviation of the exposure position due to disturbance vibration. The transmission flat plate 80 is inclined. Thereby, the light incident on the light transmission flat plate 80 is refracted in the light transmission flat plate 80 and is emitted from the light transmission flat plate 80 in a state shifted in the horizontal direction. For this reason, the light transmission flat plate driving device 306 can correct the deviation of the exposure position by tilting the light transmission flat plate 80 in a direction to cancel the exposure position due to disturbance vibration.

  In this example, as shown in FIGS. 18A and 18B, the DMD 50 has 768 sets of micromirror arrays in which 1024 micromirrors are arranged in the main scanning direction. In this example, the controller 302 performs control so that only a part of micromirror rows (eg, 1024 × 256 rows) are driven.

  In this case, a micromirror array arranged at the center of the DMD 50 as shown in FIG. 18 (A) may be used, and the micromirror arranged at the end of the DMD 50 as shown in FIG. 18 (B). A column may be used. In addition, when a defect occurs in some of the micromirrors, the micromirror array to be used may be appropriately changed depending on the situation, such as using a micromirror array in which no defect has occurred.

  Since the data processing speed of the DMD 50 is limited and the modulation speed per line is determined in proportion to the number of pixels used, the modulation speed per line can be increased by using only a part of the micromirror rows. Get faster. On the other hand, in the case of an exposure method in which the exposure head is continuously moved relative to the exposure surface, it is not necessary to use all the pixels in the sub-scanning direction.

  When the sub-scan of the photosensitive material 150 by the scanner 162 is finished and the rear end of the photosensitive material 150 is detected by the sensor 164, the stage 152 is moved to the uppermost stream side of the gate 160 along the guide 158 by the stage driving device 304. It returns to a certain origin, and again moves along the guide 158 from the upstream side to the downstream side of the gate 160 at a constant speed.

  Next, illumination that is configured by the fiber array light source 66, the condensing lens 71, the rod integrator 72, the imaging lens 74, the mirror 69, and the TIR prism 70 shown in FIG. 5 and irradiates the DMD 50 with the laser light B as illumination light. The optical system will be described. The rod integrator 72 is a translucent rod formed in, for example, a rectangular column shape, and the intensity distribution in the beam cross section of the laser beam B is made uniform while the laser beam B travels while totally reflecting inside the rod integrator 72. The entrance end face and exit end face of the rod integrator 72 are coated with an antireflection film to increase the transmittance. As described above, if the intensity distribution in the beam cross section of the laser beam B that is illumination light can be made highly uniform, non-uniform illumination light intensity can be eliminated and a high-definition image can be exposed on the photosensitive material 150.

  In this apparatus, each microlens 55a of the microlens array 55 shown in FIG. 5 deviates from the imaging position of the micromirror 62 by the lens systems 52 and 54, and is collected by the micromirror 62 and the lens systems 52 and 54. Since it is arranged at the light position, even if the DMD 50 and the microlens array 55 are slightly displaced, the light use efficiency and the extinction ratio are kept high.

  As described above, in the image exposure apparatus according to the first embodiment, even when a relative deviation occurs between the exposure position of the laser beam and the position on the stage 152 due to the disturbance vibration, the disturbance vibration is generated. Based on the above, the microlens array 55 is moved in parallel to the exposure surface and the aperture array 59 is also moved in parallel, thereby correcting the deviation of the exposure position and exposing the photosensitive material to obtain a high-quality image. Can do.

  Note that the image exposure apparatus of the present embodiment may include an optical system 51 as shown in FIG. 19 instead of the optical system 51 shown in FIG. As shown in detail in FIG. 19, the optical system 51 includes a first optical system including lens systems 52 and 54, a microlens array 55, and an aperture array 59. That is, the optical system 51 further includes an aperture array 59 provided between the microlens array 55 and the photosensitive material 150 in addition to the configuration shown in FIG.

  The aperture array 59 is formed by forming a large number of apertures (openings) 59a corresponding to the respective microlenses 55a of the microlens array 55 on the light shielding member 59b. That is, the aperture array 59 has a plurality of circular apertures (openings) 59a arranged two-dimensionally.

  The image exposure apparatus provided with such an aperture array 59 can further shape the beam and expose the photosensitive material to obtain a high-quality image.

  Further, instead of the optical system 51 shown in FIG. 19, an optical system 51 as shown in FIG. 20 may be provided. As shown in detail in FIG. 20, the optical system 51 includes a first optical system including lens systems 52 and 54, a microlens array 55, and a second microlens array. That is, the optical system 51 includes a second microlens array 81 instead of the aperture array 59 of the optical system 51 shown in FIG.

  Thus, even when the distance between the microlens array 55 and the exposure surface is small and the aperture array 59 cannot be provided between them, the second microlens is disposed between the microlens array 55 and the exposure surface. By providing the array, the photosensitive material 150 can be exposed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the site | part same as 1st Embodiment, and the detailed description is abbreviate | omitted. In the image exposure apparatus according to the second embodiment, the arrangement positions of the microlens array 55 and the aperture array 59 shown in FIG.

  Specifically, as shown in FIG. 21, the aperture array 59 has a plurality of circular apertures (openings) 59a arranged two-dimensionally on the light-shielding member 59b. Each aperture 59a is formed in the aperture array 59 so that the image of each micromirror 62 of the DMD 50 corresponds to each aperture 59a. The aperture array 59 can shape the beam shape by the aperture 59a.

  The aperture array 59 is not limited to the configuration described above, and may be configured as follows. For example, as shown in FIG. 22, in the aperture array 59, a mask 59b that shields the outer peripheral region of each microlens 55a (the portion excluding the region of a predetermined distance from the center of the microlens 55a) is formed on the light transmitting substrate 59c. It may be a thing. Accordingly, the aperture array 59 has a plurality of circular apertures 59a arranged in a two-dimensional manner.

  On the other hand, in the microlens array 55, a large number of microlenses 55a corresponding to the respective apertures 59a of the aperture array 59 (that is, corresponding to the respective micromirrors 62 of the DMD 50) are arranged two-dimensionally. These microlenses 55a form images of the portions of the corresponding apertures 59a on the photosensitive material 150, respectively.

  At this time, as shown in FIG. 23A, the light that has passed through each aperture 59a of the aperture array 59 is incident on each microlens 55a of the microlens array 55 as it is and on the photosensitive material 150 by each microlens 55a. Is imaged.

  When at least one of the displacement sensors 192, 194, and 196 detects displacement due to disturbance vibration, the microlens array driving device 305 cancels the exposure position shift due to the disturbance vibration, as shown in FIG. The microlens array 55 and the aperture array 59 are both translated. As a result, the amount of light shifted by the disturbance vibration is surely blocked by the aperture array 59, and only the light whose exposure position is not shifted is incident on each microlens 55a of the microlens array 55. As a result, the deviation of the exposure position is shielded, so that the photosensitive material 150 can be exposed without being affected by disturbance vibration, and a high-quality image can be obtained.

  The microlens array 55 and the aperture array 59 may have the following configuration instead of the configuration shown in FIG. For example, as shown in FIG. 24, a first mask 55b that shields the outer peripheral area of each microlens 55a may be formed in the microlens array 55.

  Further, the aperture array 59 is not limited to the aspect of the present embodiment, and may be integrally formed with the microlens array 55 on the light incident side or the light emitting side of the microlens array 55.

  For example, as shown in FIG. 25, a first mask 55b for shielding the outer peripheral area of each microlens 55a is formed on the light emitting side of the microlens array 55, and each microlens 55a is formed on the light incident side of the microlens array 55. A second mask 55c that shields light from the outer peripheral region may be formed. Note that only one of the first mask 55b and the second mask 55c may be formed. With such a microlens array 55, the beam shape can be shaped by the aperture 59a.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the site | part same as embodiment mentioned above, and the detailed description is abbreviate | omitted. As shown in FIG. 26, the image exposure apparatus according to the third embodiment includes an imaging optical system 51 having a configuration different from the configuration shown in FIG. 5 or FIG. 19, and an imaging optical system 51 and a photosensitive material 150. An optical path length changing member 73 disposed therebetween.

  On the light reflection side of the DMD 50, as shown in FIG. 26, an imaging optical system 51 that forms an image of the laser light B reflected by the DMD 50 on the photosensitive material 150 is disposed. The imaging optical system 51 is inserted between the first imaging optical system including the lens systems 52 and 54, the second imaging optical system including the lens systems 57 and 58, and the imaging optical system. A microlens array 55 and an aperture array 59 are provided. Note that the microlens array 55 and the aperture array 59 can be moved in a direction parallel to the exposure surface by the microlens array driving device 305 shown in FIG. 15 as in the second embodiment.

  The light beam emitted from the fiber array light source 66 is modulated by the DMD 50 and then emitted toward the photosensitive material 150 through the imaging optical system 51. In the figure, the photosensitive material 150 is sub-scanned in the direction of arrow F.

  The optical path length changing member 73 includes a wedge-shaped prism 730A and a wedge-shaped prism 730B which are adjacently arranged in directions opposite to each other. The wedge-shaped prism 730A and the wedge-shaped prism 730B are, for example, a pair of wedge-shaped prisms obtained by cutting a parallel plate made of a transparent material such as glass or acrylic on a plane inclined obliquely with respect to the parallel plane of the parallel plate. Can be adopted. Here, it is assumed that the wedge prism 730A and the wedge prism 730B are made of glass having a refractive index of 1.51.

  By combining the wedge prism 730A and the wedge prism 730B, an air layer 740 is formed between them. The wedge prism 730A and the wedge prism 730B are mounted on a holder (not shown) so that a parallel plate is formed through the air layer 740.

  The optical path length changing member 73 configured as described above has a substantial thickness of the parallel plate formed by the combination of the pair of wedge-shaped prisms 730A and 730B (from the thickness of the parallel plate formed as described above to the air Thus, the optical path length between the photosensitive material 150 and the imaging optical system 51 is corrected by changing the thickness (excluding the layer thickness t). The optical path length is a value obtained by multiplying the substantial thickness of the parallel plate by the refractive index of the parallel plate.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can also be applied to a design modified within the scope of the claims.

  For example, a mask that shields the outer peripheral region of the microlens 55a may be formed on the microlens array 55 shown in the first and third embodiments. Further, the aperture array 59 shown in FIG. 26 may be one in which the aperture 59a is formed on the light-shielding member as shown in FIG. 19, or the one in which the aperture 59a is formed by forming a mask on the light transmitting member. Good.

  In the above-described embodiment, the displacement sensor detects the vibration of the stage by a laser length measuring device arranged around the stage and calculates the positional deviation of the light on the exposure surface of the exposure beam. It is not limited to. That is, it is sufficient if it can detect a change in the relative positional relationship between the exposure head and the stage, and vibrations of both the exposure head and the stage may be detected. Further, it is possible to adopt a configuration for detecting the positional deviation of the direct exposure beam on the exposure surface.

It is a perspective view which shows the external appearance of the image exposure apparatus by the 1st Embodiment of this invention. It is a perspective view which shows the structure of the scanner of an image exposure apparatus. (A) is a top view which shows the exposed area | region formed in a photosensitive material, (B) is a figure which shows the arrangement | sequence of the exposure area by each exposure head. It is a perspective view which shows schematic structure of the exposure head of an image exposure apparatus. It is a schematic sectional drawing of an exposure head. It is the elements on larger scale which show the structure of a digital micromirror device (DMD). (A) And (B) is explanatory drawing for demonstrating operation | movement of DMD. (A) And (B) is a top view which compares the arrangement | positioning of an exposure beam, and a scanning line by the case where it does not incline and arranges DMD. (A) is a perspective view which shows the structure of a fiber array light source, (B) is a front view which shows the arrangement | sequence of the light emission point in the laser emission part of a fiber array light source. It is a figure which shows the structure of a multimode optical fiber. It is a top view which shows the structure of a combined laser light source. It is a top view which shows the structure of a laser module. It is a side view which shows the structure of a laser module. It is a partial front view which shows the structure of a laser module. It is a block diagram which shows the electric constitution of an image exposure apparatus. It is a top view of an image exposure apparatus. (A) And (B) is a figure for demonstrating the movement operation | movement of a micro lens array and a light transmissive plate. (A) And (B) is a figure which shows the example of the use area | region of DMD. It is a schematic sectional drawing of an exposure head. It is a schematic sectional drawing of an exposure head. It is a schematic sectional drawing of an exposure head. It is a figure for demonstrating a micro lens array and an aperture array. (A) And (B) is a figure for demonstrating the movement operation | movement of a micro lens array and an aperture array. It is a figure for demonstrating a micro lens array and an aperture array. It is a figure for demonstrating a microlens array. It is a schematic sectional drawing of an exposure head.

Explanation of symbols

LD1 to LD7 GaN semiconductor laser 30, 31 Multimode optical fiber 50, 250 Digital micromirror device (DMD)
DESCRIPTION OF SYMBOLS 51 Optical system 52,54 Lens system 55 Micro lens array 55a Micro lens 57,58 Lens system 59 Aperture array 59a Aperture 62 Micro mirror 66 Laser module 66 Fiber array light source 68 Laser emitting part 72 Rod integrator 150 Photosensitive material

Claims (6)

A spatial light modulation element that modulates the irradiated light in each pixel portion arranged in a two-dimensional manner;
A light source for irradiating the spatial light modulator with light;
A first optical system that focuses the light that has passed through the spatial light modulator and forms an image of the pixel unit;
A microlens array that forms an image on a photosensitive material with each of the microlenses arranged in a two-dimensional manner by a plurality of light beams from the pixel unit that has passed through the first optical system;
A displacement detection means for detecting a relative displacement between the photosensitive material and the light from the microlens array caused by disturbance vibration;
A microlens array moving means for moving the microlens array based on the positional deviation detected by the positional deviation detection means;
An image exposure apparatus comprising: The image exposure apparatus according to claim 1, further comprising: a second optical system that forms and projects an image formed by the microlens array on the photosensitive material. A light transmission flat plate that transmits light from the first optical system and enters the microlens array;
Light transmission flat plate tilting means for tilting the light transmission flat plate so that an angle formed by the light transmission flat plate and the microlens array changes based on the positional shift detected by the positional shift detection means. The image exposure apparatus according to claim 1 or 2. An aperture array on which a mask for shielding the outer peripheral area of each microlens of the microlens array is formed;
The image according to any one of claims 1 to 3, wherein the microlens array moving unit moves the aperture array together with the microlens array based on the positional shift detected by the positional shift detection unit. Exposure device. The image exposure apparatus according to claim 4, wherein the aperture array is formed integrally with the microlens array on a light incident side or a light emitting side of the microlens array. The image exposure apparatus according to claim 1, wherein the microlens array is formed with a mask that shields an outer peripheral region of each microlens on at least one of a light incident side and a light emitting side.

Images