JP2005234265A - Exposure head, apparatus and method for exposing image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily change the condensation size of exposure light in an apparatus for irradiating a photosensitive material with light modulated by a two-dimensional spatial optical modulation element and exposing the photosensitive material. <P>SOLUTION: Regarding the exposure head provided with the two-dimensional spatial optical modulation element 50 having many pixels for modulating the emitted light in accordance with respective image data, 1st image forming optical systems 52 and 54 arranged on the optical path of the light modulated by the spatial optical modulation element 50, a microlens array 55 where microlenses 55a corresponding to respective pixels of the spatial optical modulation element 50 are arranged in an array state, and 2nd image forming optical systems 57 and 58 which are arranged on the optical path of the light passing through the microlens array 55 so as to form the image of the modulated light on a prescribed photosensitive material 150, a plurality of adjacent pixels of the spatial optical modulation element 50 are made correspond to one microlens 55a of the microlens array 55 so that the light emitted from the plurality of adjacent pixels of the element 50 can be made incident on the one microlens 55a of the microlens array 55. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image exposure method, an image exposure apparatus used therefor, and an exposure head constituting the image exposure apparatus.

  2. Description of the Related Art Conventionally, there has been known an image exposure apparatus in which light modulated by a spatial light modulation element is passed through an imaging optical system, and an image of this light is formed on a photosensitive material, thereby exposing the photosensitive material. This type of image exposure apparatus basically includes a spatial light modulation element in which a large number of pixels that modulate irradiated light according to image data are two-dimensionally arranged, and the two-dimensional spatial light modulation element. A light source that emits light and an imaging optical system that forms an image of light modulated by the spatial light modulation element are provided. Non-Patent Document 1 and Japanese Patent Application No. 2002-149886 by the applicant of the present application show an example of an image exposure apparatus having the above basic configuration.

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

  Therefore, as shown in the specification of Japanese Patent Application No. 2002-149886, a first imaging optical system is disposed in the optical path of the light modulated by the spatial light modulation element, and an imaging surface formed by this imaging optical system. A microlens array in which microlenses corresponding to the pixels of the spatial light modulation element are arranged in an array is arranged, and an image of the modulated light is formed on the optical path of the light that has passed through the microlens array. It is considered that a second imaging optical system that forms an image is arranged on the top and an image is enlarged and projected by the first and second imaging optical systems. In addition, Patent Document 1 discloses a configuration in which a spatial light modulation element and a microlens array are combined, but here, enlargement of an image is not considered.

In the above configuration, while the size of the image projected on the photosensitive material is enlarged, the light from each pixel of the spatial light modulation element is collected by each microlens of the microlens array, so that the condensed light in the projected image is collected. The spot size is reduced, so that the sharpness of the image can be kept high. Then, the spatial light modulation element and the photosensitive material are moved relative to each other to perform scanning exposure, and if both are arranged so that the alignment direction of the condensed spots is inclined with respect to the moving direction at that time, a certain row of Since the portion between the portions exposed by the focused spot can be exposed by the focused spot in another row, the pixel density can be increased.
JP 2001-305663 A Akihito Ishikawa "Development shortening and mass production application by maskless exposure", "Electrotronics packaging technology", Technical Research Committee, Vol.18, No.6, 2002, p.74-79

  By the way, when the image exposure is performed using the combination of the spatial light modulator and the microlens array as described above, it may be desired to change the condensing size of the exposure light. As one measure for that, it is conceivable to prepare a plurality of microlens arrays having different focal lengths of the microlenses, and to exchange these microlens arrays in accordance with a desired condensing size. However, it is very difficult to replace the microlens array while maintaining the positional accuracy between the two-dimensional spatial light modulator having usually several hundreds of thousands or more of pixels and the generally required level of about 1 μm. Therefore, a complicated means is required for the realization, and the cost of the exposure apparatus is greatly increased.

  In addition, it is conceivable to change the light condensing size by changing the optical magnification of the imaging optical system after the microlens array. However, in such a case, not only the light condensing size but also the size of the exposed area is large. That will also change. In such an exposure apparatus, in particular, in an exposure apparatus that uses a plurality of exposure heads and connects the exposure areas of the exposure heads to expose one image, the connecting portion of the plurality of exposure areas changes the condensing size. Along with it. In order to deal with this problem, it is necessary to change the position of the exposure head every time the light collection size is changed. However, such an operation is practically impossible.

  Further, an apparatus for exposing the photosensitive material by directly irradiating the photosensitive material with light emitted from the microlens array without providing the second imaging optical system described above is also considered. However, there is a problem that it is difficult or impossible to change the light collection size.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image exposure apparatus and method capable of easily changing the condensing size of exposure light, and an exposure head capable of realizing the same. And

An exposure head according to the present invention comprises:
A two-dimensional spatial light modulation element in which a large number of pixels that modulate irradiated light according to image data are arranged two-dimensionally;
A light source for irradiating light to the spatial light modulator;
An imaging optical system disposed in an optical path of light modulated by the spatial light modulator;
In an exposure head comprising microlenses corresponding to each pixel of the spatial light modulator and arranged in an array, and comprising a microlens array disposed in the vicinity of an imaging surface by the imaging optical system,
The plurality of pixels and one microlens correspond to each other so that light emitted from a plurality of adjacent pixels of the spatial light modulator can be incident on one microlens of the microlens array. It is.

  The present invention having the above-described configuration is an exposure that includes a second imaging optical system that is disposed in the optical path of the light that has passed through the microlens array and forms an image of the modulated light on a photosensitive material. It is preferably applied to the head.

  In the above configuration, the plurality of pixels corresponding to one microlens is preferably n × n (n is an odd number) pixels.

On the other hand, an image exposure apparatus according to the present invention includes the above-described exposure head according to the present invention and a drive circuit that drives each pixel of the two-dimensional spatial light modulator in accordance with image data. An apparatus for irradiating a photosensitive material with light modulated by the above and exposing the photosensitive material to an image,
A state in which all of the plurality of adjacent pixels of the spatial light modulation element are driven in parallel and a state in which only some of the pixels selected from the plurality of pixels are driven in parallel based on image data relating to one pixel of the exposure image. Means for controlling the operation of the drive circuit in a switchable manner is provided.

  The number of pixels selected from the plurality of pixels may be plural or one, and when it is one, it is driven alone, but “parallel driving” includes such a case. Shall be. That is, “parallel drive” in this case refers to driving some pixels selected from a plurality of pixels based on the same image data without being driven independently based on different image data. Shall.

  Further, as described above, the pixel selection state in which only some of the pixels are selected may be set only one way, or a plurality of pixel selection states may be set.

Another image exposure apparatus according to the present invention includes an exposure head in which a plurality of pixels corresponding to the one microlens are n × n (n is an odd number) pixels among the exposure heads according to the present invention. In addition to this, it has a drive circuit for driving each pixel of the two-dimensional spatial light modulator in accordance with image data, and the photosensitive material is irradiated with light modulated by the spatial light modulator. An apparatus for image exposure,
A state in which all of the plurality of adjacent pixels of the spatial light modulator are driven in parallel on the basis of image data relating to one pixel of the exposure image, and a partial pixel selected from the plurality of pixels, the selection pattern having the selected pattern The present invention is characterized by comprising means for controlling the operation of the drive circuit so as to be able to switch between a state in which only some of the pixels that are line-symmetric with respect to any pixel arrangement direction are driven in parallel.

  In this apparatus, as described above, only one or a plurality of pixel selection states for selecting only some pixels may be set.

  On the other hand, the image exposure method according to the present invention is characterized in that the image indicated by the image data is exposed onto the photosensitive material by using the image exposure apparatus according to the present invention as described above.

  In the exposure head of the present invention, the plurality of pixels correspond to one microlens so that light emitted from adjacent pixels of the spatial light modulation element can enter one microlens of the microlens array. Therefore, it is possible to switch the driving state so that all of the plurality of pixels are driven in parallel or only a part of the plurality of pixels is driven in parallel based on the image data relating to one pixel of the exposure image. The beam diameter and profile of light incident on one microlens through the imaging optical system are different between the case where all of the plurality of pixels are driven in parallel and the case where only some of them are driven as described above. As a result, the condensing size of the microlens can be changed.

  In addition, when the exposure head of the present invention is configured to include the second imaging optical system as described above, the condensing size by the microlens can be changed as described above. As a result, the light collection size on the photosensitive material by the second imaging optical system can be changed.

  The image exposure apparatus of the present invention is configured to drive all of a plurality of adjacent pixels of the spatial light modulation element in parallel based on image data relating to one pixel of the exposure image, and only some of the pixels selected from the plurality of pixels. Means for controlling the operation of the drive circuit so as to be able to switch between the state of driving the lens and the condensing size of the microlens and the second imaging optical system can actually be changed as described above. .

  In addition, when only one pixel selection state for selecting only a part of the plurality of pixels is set, the condensing size is set in two ways in total, including a state in which all of the plurality of pixels are driven in parallel. Can be changed. In addition, when the pixel selection state is set in two ways, for example, the light collection size can be changed in three ways in total with the state in which all of the plurality of pixels are driven in parallel.

  In the image exposure apparatus according to the present invention, in particular, an exposure head in which a plurality of pixels corresponding to one microlens is n × n (n is an odd number) pixels is used, while a two-dimensional spatial light modulator is used. As a drive circuit for driving each pixel, a state in which all of the plurality of adjacent pixels of the spatial light modulator are driven in parallel and only a part of the pixels whose selection pattern is line symmetric with respect to any of the pixel arrangement directions are used. When a switch that can be switched between the state of selecting and driving in parallel is used, when only some of the pixels are selected and driven, the profile of light incident on each microlens is related to any of the above pixel alignment directions. Since it is also line symmetric, the light incident on the microlens can be condensed to a desired spot size.

  In the exposure head of the present invention, a transmissive type or a reflective type can be used as the two-dimensional spatial light modulator. Recently, a digital micromirror device (registered trademark of Texas Instruments Inc., hereinafter referred to as DMD) is being applied to many fields as one of the reflective spatial light modulation elements. Also, this DMD can be preferably used.

  The DMD is a mirror device configured by arranging a large number of micromirrors constituting one pixel in a grid pattern (for example, 1024 × 768). Each of the micro mirrors is configured to be able to tilt independently and take two angular positions, and the illumination light irradiated thereon is reflected in two different directions depending on the angular position. Therefore, if the photosensitive material is arranged at a position where the illumination light reflected in one of the two directions is incident, the light is incident on the photosensitive material when the illumination light is reflected in the other of the two directions. Therefore, the light irradiated to the photosensitive material can be spatially modulated by one minute mirror unit. Therefore, if the angular position of the micromirror is controlled according to the image information, the light corresponding to the image information is irradiated onto the photosensitive material and image exposure is performed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  Here, an exposure head according to an embodiment of the present invention will be described. First, an image exposure apparatus to which the exposure head is applied will be described in detail.

[Configuration of exposure apparatus]
As shown in FIG. 1, the image exposure apparatus includes a flat plate-shaped 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-shaped installation table 156 supported by the four legs 154. The stage 152 is disposed so that the longitudinal direction thereof faces the stage moving direction, and is supported by a guide 158 so as to be reciprocally movable. Note that this exposure apparatus is provided with a stage drive unit 304 (see FIG. 9), which will be described later, that drives a stage 152 as sub-scanning means along a guide 158.

  A U-shaped gate 160 is provided at the center of the installation table 156 so as to straddle the movement path of the stage 152. Each of the end portions 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 mth row and the nth column, it is expressed as an exposure head 166 _mn .

An exposure area 168 by the exposure head 166 has a rectangular shape with the short side in the sub-scanning direction. Therefore, as the stage 152 moves, a strip-shaped exposed area 170 is formed on the photosensitive material 150 for each exposure head 166. 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 FIGS. 4 and 5, each of the exposure heads 166 _{11 to} 166 _mn is a digital micromirror device (as a spatial light modulation element that modulates an incident light beam for each pixel in accordance with image data. DMD) 50. The DMD 50 is connected to a later-described controller 302 (see FIG. 9) having 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. The area to be controlled will be described later. 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. The control of the angle of the reflecting surface will be described later.

  On the light incident side of the DMD 50, a BALD (broad area type semiconductor laser) 66 as an illumination light source, a lens system 67 for condensing the laser light B emitted from the BALD 66 on the DMD, and a laser that has passed through the lens system 67 A mirror 69 that reflects the light B toward the DMD 50 is 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 includes a condensing lens 71 for condensing the laser light B as illumination light emitted from the BALD 66, and a rod inserted in the optical path of the light that has passed through the condensing lens 71. It is composed of a type optical integrator (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 beam B emitted from the BALD 66 to enter the DMD 50 as a light beam having a uniform beam cross-sectional intensity. The shape and the like of the rod integrator 72 will be described in detail later.

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

  On the light reflection side of the DMD 50, an image forming optical system 51 for forming an image of the laser light B reflected by the DMD 50 on a photosensitive material 150 as a recording medium is disposed. The imaging optical system 51 is schematically shown in FIG. 4, but as shown in detail in FIG. 5, a first imaging optical system comprising lens systems 52 and 54 and a first imaging system comprising lens systems 57 and 58 are shown. The image forming optical system includes two image forming optical systems, a microlens array 55 inserted between these image forming optical systems, and an aperture array 59. The microlens array 55 is made of, for example, an optical glass BK7, and includes a large number of microlenses 55a. For example, the micro lens 55a has a focal length of 0.19 mm and an NA (numerical aperture) of 0.11. The aperture array 59 is formed by forming a large number of apertures 59a corresponding to the respective microlenses 55a of the microlens array 55.

  The first image-forming optical system forms an image on the microlens array 55 by enlarging the image by the DMD 50 three times. Then, the second imaging optical system enlarges the image passing through the microlens array 55 to 1.67 times and forms and projects it on the photosensitive material 150. Therefore, as a whole, the image formed by the DMD 50 is magnified five times and formed on the photosensitive material 150 and projected.

  In this example, a prism pair 73 is disposed between the second imaging optical system and the photosensitive material 150, and the prism pair 73 is moved in the vertical direction in FIG. The focus can be adjusted. In the figure, the photosensitive material 150 is sub-scanned in the arrow Y direction.

  As shown in FIG. 6, the DMD 50 is a structure in which a micromirror (micromirror) 62 is supported by a support column on an SRAM cell (memory cell) 60 and a large number of pixels (pixels) (for example, (1024 × 768) micromirrors arranged in a lattice pattern. Each pixel is provided with a micromirror 62 supported by a support column at the top, and a material having a high reflectance such as aluminum is deposited on the surface of the micromirror 62. The reflectance of the micromirror 62 is 90% or more. Directly below the micromirror 62, a silicon gate CMOS SRAM cell 60 manufactured on a normal semiconductor memory manufacturing line is disposed via a support including a hinge and a yoke, and the entire structure is monolithic. ing.

  When a digital signal is written to the SRAM cell 60 of the DMD 50, the micromirror 62 supported by the support is tilted within a range of ± α degrees (eg, ± 10 degrees) with respect to the substrate side on which the DMD 50 is disposed with the diagonal line as the center. It is done. 7A shows a state where the micromirror 62 is tilted to + α degrees when the micromirror 62 is in the on state, and FIG. 7B shows a state where the micromirror 62 is tilted to −α degrees when the micromirror 62 is 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. The 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 micromirror 62 in the off state travels.

  Further, it is preferable that the DMD 50 is disposed with a slight inclination so that the short side forms a predetermined angle (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 plurality of micro mirror rows in which a large number of micro mirrors are arranged in the longitudinal direction are arranged in the short direction, but as shown in FIG. The pitch P ₁ of the scanning locus (scanning line) of the exposure beam 53 by the micromirror becomes narrower than the pitch P ₂ of the scanning line when the DMD 50 is not inclined, and the resolution can be greatly improved. On the other hand, since the inclination angle of the DMD 50 is very small, the scanning width W ₂ when the DMD 50 is inclined and the scanning width W ₁ when the DMD 50 is not inclined 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 the direction orthogonal to the sub-scanning direction instead of inclining the DMD 50.

  FIG. 9 shows the electrical configuration of the image exposure apparatus of this example. As shown here, a modulation circuit 301 is connected to the overall control unit 300, and a controller 302 for controlling the DMD 50 is connected to the modulation circuit 301. The overall control unit 300 is connected to an LD drive circuit 303 that drives the laser module 64. Further, a stage driving device 304 that drives the stage 152 is connected to the overall control unit 300.

  Next, with reference to FIG. 10, the correspondence between the micromirror 62 serving as the DMD 50 pixel and the microlens 55a of the microlens array 55 will be described. As shown here, in this embodiment, 3 × 3 = 9 micromirrors 62 adjacent to each other correspond to one microlens 55 a of the microlens array 55.

  Then, the controller 302 shown in FIG. 9 is configured to drive the 3 × 3 = 9 micromirrors 62 in parallel based on the image data indicating one pixel of the exposure image, and among the nine micromirrors 62. It is formed so that it can be switched between a state in which only a part of it is driven. That is, in this example, as shown in FIGS. 11A, 11B, and 11C, the first state in which all nine micromirrors 62 are driven in parallel based on the image data for one pixel, the center The controller 302 sets one of a second state in which the eight micromirrors 62 excluding the pixels are driven in parallel and a third state in which only the central pixel is driven. In FIG. 11, the hatched ones are non-selected micromirrors 62 and the other micromirrors 62 are driven (the same applies hereinafter).

[Operation of exposure apparatus]
Next, the operation of the exposure apparatus will be described. At the time of image exposure, image data corresponding to the exposure pattern is input from the modulation circuit 301 shown in FIG. 9 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 having the photosensitive material 150 adsorbed on 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. In the case of this example, the size of the micromirror that becomes one pixel is 14 μm × 14 μm.

  When the laser beam B is irradiated from the BALD 66 to the DMD 50, the laser beam B reflected when the micromirror 62 of the DMD 50 is in the on state is imaged on the photosensitive material 150 by the lens systems 54 and 58. In this way, the laser beam B emitted from the BALD 66 is turned on / off for each micromirror 62, and the photosensitive material 150 is exposed with the laser beam B. 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.

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

[Illumination optics]
Next, an illumination optical system that includes the BALD 66, the condenser 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. Will be described.

  In the BALD 66, a wide light emitting region of, for example, about 100 to 400 μm is formed in the active layer 66a to achieve high output. Laser light B is emitted from the BALD 66 in a divergent light state, and the laser light B is collected by the condenser lens 71 and guided to the incident end face (left end face in FIG. 5) of the rod integrator 72. The rod integrator 72 is made of a light transmitting member having a substantially square columnar shape, and the laser beam B incident on the rod integrator 72 from the incident end face travels while repeating total reflection at the interface between the side end face and air. Then, the light is emitted from the emission end face (the right end face in FIG. 5).

  The laser beam B emitted from the rod integrator 72 is condensed by the imaging lens 74 and guided to the DMD 50 to illuminate the DMD 50. As the laser beam B travels in the rod integrator 72 as described above, the intensity distribution in the beam cross section is made uniform. Therefore, it becomes possible to illuminate the DMD 50 with the laser beam B having a uniform intensity.

  Here, a description will be given of changing the condensing size of the laser beam B when the photosensitive material 150 is exposed by the laser beam B. FIG. In this embodiment, as described above with reference to FIGS. 11A, 11B, and 11C, an exposure image is obtained with respect to 3 × 3 = 9 micromirrors 62 corresponding to one microlens 55a. The first state in which all the nine micromirrors 62 are driven in parallel, the second state in which the eight micromirrors 62 excluding the central pixel are driven in parallel, based on the image data for one pixel, only the central pixel Any one of the third states for driving is set by the controller 302.

  In the first state, the second state, and the third state, the beam diameter and profile of the laser beam B that is collected by the first imaging optical system including the lens systems 52 and 54 and is incident on one microlens 55a is determined. Since they are different from each other, the condensing sizes of the microlenses 55a are different from each other. As a result, the condensing size on the photosensitive material 150 by the second imaging optical system including the lens systems 57 and 58 can be changed. . Here, (A), (B), and (C) of FIG. 12 show schematic profiles of the laser beam B in the first state, the second state, and the third state, respectively. As shown here, the condensing size of the laser beam B is maximum in the third state, minimum in the second state, and intermediate between them in the first state.

  In the present embodiment, one microlens 55a corresponds to 3 × 3 = 9 micromirrors 62, while the controller 302 selects a mirror selection pattern in the pixel arrangement direction from the nine micromirrors 62. In either case, one (in the second state) or eight (in the third state) is selected and driven so as to be line symmetric. Therefore, in the second state and the third state, the profile of the laser beam B incident on the microlens 55a is axisymmetric with respect to any of the pixel alignment directions, so that the light incident on the microlens 55a is a desired spot. It can be concentrated to size.

  Note that the mirror selection pattern for selecting and driving only a part of the 3 × 3 = 9 micromirrors 62 is particularly limited to the patterns shown in FIGS. 11B and 11C. Instead, for example, a selection pattern as shown in FIG. 13 can be adopted.

  Further, the number of micromirrors 62 corresponding to one microlens 55a is not limited to 3 × 3 = 9 in the above-described embodiment. For example, 2 × 2 = 4, 4 × 4 = 16, 5 × 5 = 25 or the like may be used. For example, when 2 × 2 = 4, a state in which all four micromirrors 62 are driven in parallel as shown in FIG. 14A, and two micromirrors 62 selected as shown in FIG. Are switched in parallel, the condensing size of the laser beam B can be changed.

  The present invention can be similarly applied to the case of using a two-dimensional spatial light modulation element other than the DMD, and in this case, the same effect as described above can be obtained.

  Further, the embodiment using the BALD 66 as the illumination light source has been described above. However, the present invention relates to a semiconductor laser other than the BALD, a combined laser light source, a semiconductor laser light source formed by combining a semiconductor laser and an optical fiber, and various lamps. It is also possible to apply to an exposure head using the above as an illumination light source, and in this case, the same effect as described above can be obtained.

The perspective view which shows the external appearance of the image exposure apparatus by one Embodiment of this invention 1 is a perspective view showing a configuration of a scanner of the image exposure apparatus in FIG. (A) is a plan view showing an exposed area formed on a photosensitive material, and (B) is a view showing an arrangement of exposure areas by each exposure head. 1 is a perspective view showing a schematic configuration of an exposure head of the image exposure apparatus of FIG. Sectional drawing of the illumination optical system which comprises the image exposure apparatus of FIG. 1 of the subscanning direction along an optical axis Partial enlarged view showing the configuration of a digital micromirror device (DMD) (A) And (B) is explanatory drawing for demonstrating operation | movement of DMD. (A) and (B) are plan views showing the arrangement of the exposure beam and the scanning line in a case where the DMD is not inclined and in a case where the DMD is inclined. Block diagram showing the electrical configuration of the image exposure apparatus Schematic showing the correspondence between DMD pixels and each lens in the microlens array Explanatory drawing which shows the drive pixel selection pattern of DMD Explanatory drawing which shows the condensing spot size for every drive pixel selection pattern of DMD Explanatory drawing which shows another example of the drive pixel selection pattern of DMD Explanatory drawing which shows another example of the drive pixel selection pattern of DMD

Explanation of symbols

50 Digital micromirror device (DMD)
52, 54 Lens system (first imaging optical system)
55 Micro lens array
55a Micro lens
57, 58 Lens system (second imaging optical system)
62 Micromirror
66 BALD (broad area type semiconductor laser)
72 Rod integrator
74 Imaging lens
150 photosensitive material
152 stages
162 Scanner
166 Exposure head
168 Exposure area
170 Exposed area

Claims (6)

A two-dimensional spatial light modulation element in which a large number of pixels that modulate irradiated light according to image data are arranged two-dimensionally;
A light source for irradiating light to the spatial light modulator;
An imaging optical system disposed in an optical path of light modulated by the spatial light modulator;
In an exposure head comprising microlenses corresponding to each pixel of the spatial light modulator and arranged in an array, and comprising a microlens array disposed in the vicinity of an imaging surface by the imaging optical system,
The exposure is characterized in that the plurality of pixels correspond to one microlens so that light emitted from a plurality of adjacent pixels of the spatial light modulation element can enter one microlens of the microlens array. head.   2. A second imaging optical system that is disposed in an optical path of light that has passed through the microlens array and forms an image of the modulated light on a predetermined photosensitive material. 1. The exposure head according to 1.   3. The exposure head according to claim 1, wherein n × n (n is an odd number) pixels correspond to the one microlens as the plurality of pixels. An exposure head according to any one of claims 1 to 3, and a drive circuit that drives each pixel of the two-dimensional spatial light modulator in accordance with image data, and light modulated by the spatial light modulator An apparatus for irradiating a photosensitive material and exposing the image to the photosensitive material,
A state in which all of the plurality of adjacent pixels of the spatial light modulation element are driven in parallel and a state in which only some of the pixels selected from the plurality of pixels are driven in parallel based on image data relating to one pixel of the exposure image. An image exposure apparatus comprising means for controlling the operation of the drive circuit in a switchable manner. 4. An exposure head according to claim 3, and a drive circuit for driving each pixel of the two-dimensional spatial light modulator in accordance with image data, and irradiating the photosensitive material with light modulated by the spatial light modulator. An apparatus for exposing an image to the photosensitive material,
A state in which all of the plurality of adjacent pixels of the spatial light modulator are driven in parallel on the basis of image data relating to one pixel of the exposure image, and a partial pixel selected from the plurality of pixels, the selection pattern having the selected pattern An image exposure apparatus comprising means for controlling the operation of the drive circuit so as to be able to switch between a state in which only some of the pixels that are line-symmetric with respect to any of the pixel arrangement directions are driven in parallel.   6. An image exposure method comprising exposing an image indicated by image data onto a photosensitive material using the image exposure apparatus according to claim 4 or 5.

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