JP2004062156A - Exposure head and exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a decrease in use efficiency of a laser beam emitting from a laser emission part of an illuminating means and to expose the objective surface for exposure with a beam spot having a desired spot diameter and a spot form. <P>SOLUTION: In the exposure head 166, first microlenses 74 are two-dimensionally arranged so as to correspond to the respective micromirrors in a DMD (digital micromirror device) 50, and apertures 78 in an aperture array 76 are two-dimensionally arranged in the backward focal position of the first microlenses 74. The exposure head 166 projects a reduced image of the light source formed in the backward focal position by the first microlenses 74 onto the objective surface 56 for exposure through a lens system 80, 82 to expose the surface 56 with the image of the light source as a beam spot BS. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exposure head for exposing an exposure surface of a photosensitive material or the like with a light beam spatially modulated by a spatial light modulation element in accordance with image data, and an exposure apparatus including the exposure head.
[0002]
[Prior art]
Conventionally, various exposure apparatuses that perform image exposure with a light beam modulated in accordance with image data using a spatial light modulation element such as a digital micromirror device (DMD) have been proposed.
[0003]
For example, as the DMD, a mirror device in which a number of micromirrors whose reflection surfaces change in response to a control signal are two-dimensionally arranged on a semiconductor substrate such as silicon is used, and exposure using the DMD is performed. As shown in FIG. 19, the apparatus is reflected by a light source 1 that emits a laser beam, a lens system 2 that collimates the laser beam emitted from the light source 1, and DMDs 3 and DMD 3 that are disposed at substantially focal positions of the lens system 2. The lens systems 4 and 6 form an image of the laser beam on the exposure surface 5. Note that DMD 3 is a reflective spatial light modulator, but FIG. 19 shows that the laser beam is emitted from DMD 3 to the exposure surface 5 side without being deflected in order to simplify the description. ing.
[0004]
In this exposure apparatus, each of the micromirrors of the DMD 3 is on / off controlled by a control device (not shown) by a control signal generated according to image data or the like to modulate (deflect) the laser beam, and the exposure surface is modulated by the modulated laser beam. Is exposed. Here, the lens systems 4 and 6 are configured as a magnifying optical system, and the exposure area on the exposure surface 5 is enlarged with respect to the surface portion of the DMD 3 on which the micromirrors are arranged.
[0005]
In the exposure apparatus as described above, the micromirror in DMD and the exposure surface 56 are usually conjugated with each other, and the reflected light image by the micromirror is formed on the exposure surface 5 by the lens systems 4 and 6, and this reflection is performed. The exposure surface 5 is exposed using the optical image as a beam spot.
[0006]
[Problems to be solved by the invention]
However, when the area of the exposure area with respect to the exposure surface 5 is enlarged with respect to the area of the surface portion of the DMD 3 by the lens systems 4 and 6, the area (spot diameter) of the beam spot on the exposure surface 5 is also enlarged according to the enlargement ratio. Therefore, the MTF (Modulation Transfer Function) characteristic on the exposure surface 5 is lowered according to the enlargement ratio of the exposure area.
[0007]
Therefore, the exposure apparatus as described above is provided with a plurality of apertures having an aperture ratio corresponding to a required spot diameter between the DMD 3 and the lens system 4, and the laser beam modulated by the micromirrors of the DMD 3 by this aperture. There is one that adjusts the spot diameter on the exposure surface 5 to a desired size by shielding a part of the (light beam) and shapes the shape of the beam spot (spot shape) to a desired shape. However, in the exposure apparatus as described above, when the spot diameter on the exposure surface 5 is adjusted by the aperture, the light utilization efficiency of the laser beam emitted from the light source 1 decreases as the reduction ratio with respect to the spot diameter increases. Even when the spot shape is shaped to be significantly different from the reflected light image of the micromirror by the aperture, the light utilization efficiency of the laser beam emitted from the light source 1 is greatly reduced.
[0008]
The object of the present invention is to reduce the use efficiency of the laser beam emitted from the laser emitting portion of the illumination means in consideration of the above fact, and to expose the exposure surface with a beam spot having a desired spot diameter and spot shape. It is an object of the present invention to provide an exposure head and an exposure apparatus that can be used.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an exposure head according to a first aspect of the present invention is an exposure head for two-dimensionally exposing an exposure surface with a plurality of laser beams, wherein the laser beam is emitted from a laser emitting portion. The illuminating means that emits and a plurality of pixel portions whose light modulation states change according to the control signal are two-dimensionally arranged, and the laser beam incident from the laser emitting portion is exposed and non-exposed by the pixel portion. A spatial light modulation element that modulates any of the states; a first optical system that forms an image of each pixel portion in the spatial light modulation element; and a two-dimensional correspondence to the plurality of pixel portions And a plurality of first microlenses that are respectively supported at the imaging positions of the plurality of pixel portions, and the laser output formed at the rear focal position of the first microlens. A light source image parts projected to the exposure surface, characterized by exposing the exposure surface of the light source image as a beam spot.
[0010]
In the exposure head according to the first aspect, the first microlenses are two-dimensionally arranged so as to correspond to the plurality of pixel portions in the spatial light modulator, and are respectively disposed at the imaging positions of the plurality of pixel portions. A laser beam that is modulated to an exposure state by each pixel unit of the spatial light modulator by projecting a light source image formed on the focal plane of the first microlens onto the exposure surface and exposing the exposure surface. Can be reduced and enlarged by the first microlens, for example, the first optical system is an enlargement optical system, and the area of the exposure area relative to the exposure surface by the first optical system is the surface of the spatial light modulator. Even when enlarged with respect to the portion, if the first microlens having positive lens power is used, the beam diameter of the beam spot projected on the exposure surface can be reduced, The reduction in MTF characteristics in exposed regions can be prevented.
[0011]
Further, in the exposure head according to claim 1, since the light source image of the laser emitting unit is projected onto the exposure surface and the exposure surface is exposed using this light source image as a beam spot, for example, when DMD is used as the spatial light modulation element In the DMD, it is possible to prevent the light amount distribution at the center portion of the beam spot projected on the exposure surface from being lowered due to the influence of the hole-like non-reflecting portion formed at the center portion of the reflecting surface of the micromirror in the DMD, and to obtain a uniform light amount The exposure surface can be exposed by a beam spot having a distribution.
[0012]
An exposure head according to a second aspect of the present invention is the exposure head according to the first aspect, wherein a light source image group which is a set of light source images respectively formed by the plurality of first microlenses is formed on the exposure surface. And a second optical system that forms an image.
[0013]
An exposure head according to a third aspect of the present invention is the exposure head according to the first or second aspect, wherein the beam spot has a spot diameter and a spot shape on the exposure surface in the vicinity of a rear focal position of the first microlens. An aperture having a corresponding opening diameter and opening shape is arranged.
[0014]
According to the above-described exposure head, the aperture disposed in the vicinity of the back focal position has an aperture diameter and an aperture shape corresponding to the spot diameter and spot shape of the beam spot on the exposure surface, so that the first micro Light that becomes a noise component such as scattered light and diffracted light in the laser beam emitted from the lens can be blocked by the aperture, so that the beam spot projected on the exposure surface can be accurately shaped into the required spot shape, and the beam spot It is possible to prevent light that is a noise component from being projected outside.
[0015]
An exposure head according to a fourth aspect of the present invention is the exposure head according to the third aspect, wherein a second microlens having a positive lens power is disposed at a rear focal position of the first microlens. Features.
[0016]
According to the exposure head of the fourth aspect, the spread angle of the light beam that has passed through the aperture (rear focal position) of the first microlens can be reduced by the second microlens arranged at the rear focal position. Compared with the case where only the first microlens is used, it is possible to effectively suppress the deterioration of the focal depth of the beam spot on the exposure surface which increases as the spread angle of the light beam passing through the aperture increases.
[0017]
An exposure head according to a fifth aspect of the present invention is the exposure head according to the first, second, third, or fourth aspect, wherein a contour shape along a direction perpendicular to the optical axis of the laser emitting portion is a beam spot on the exposure surface. It is characterized by having a shape corresponding to this shape.
[0018]
According to the exposure head of the fifth aspect, since it is possible to project onto the exposure surface as a beam spot having a contour shape substantially similar to the contour shape of the laser emitting portion, the exposure surface can be exposed with a beam spot having a desired spot shape. .
[0019]
An exposure apparatus according to a sixth aspect of the present invention is the exposure head according to the first, second, third, fourth, or fifth aspect, and the exposure head is configured such that the arrangement direction of the plurality of pixel portions is a scanning direction with respect to the exposure surface. And moving means for relatively moving the exposure head in the scanning direction during exposure on the exposure surface.
[0020]
According to the above-described exposure apparatus, j pixel portions are arranged in the spatial light modulation element along a direction (row direction) substantially orthogonal to the scanning direction, and an orthogonal direction (corresponding to the scanning direction substantially) ( When k pixel portions are arrayed in the spatial light modulator along the column direction), exposure is performed while supporting the exposure head so that the array direction of the pixel portions of the spatial light modulator is inclined with respect to the scanning direction. By relatively moving the head in the scanning direction, an integral multiple of j, that is, (j × N) laser beams, which are different from each other on the same scanning line on the exposure surface, according to the inclination angle of the pixel portion in the arrangement direction with respect to the scanning direction. Since the position can be exposed, the pixel density of the exposure pattern formed on the exposure surface can be increased to the required density by appropriately adjusting the tilt angle in the arrangement direction of the pixel portions, and substantially the same on the same scanning line. Position of( Can be exposed k / N times (multiple exposure) with a laser beam modulated by k / N pixel units arranged in the same row of spatial light modulators, so that an exposure pattern formed on the exposure surface Can also improve the resolution.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[Configuration of exposure apparatus]
As shown in FIG. 1, the exposure apparatus 142 according to the embodiment of the present invention includes a flat plate stage 152 that holds a sheet-like photosensitive material 150 by adsorbing to the surface. Two guides 158 extending along the stage moving direction are installed on the upper surface of the thick plate-shaped installation base 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 exposure device 142 is provided with a drive device (not shown) for driving the stage 152 along the guide 158.
[0022]
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 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) detection 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 detection 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 detection sensor 164 are connected to a controller (not shown) that controls them.
[0023]
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). ing. 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.
[0024]
An exposure area 168 by the exposure head 166 has a rectangular shape with a short side in the 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 nth column of the m-th row, it is expressed as an exposure area 168mn.
[0025]
Also, 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 scanning direction without gaps. The arrangement direction is shifted by a predetermined interval (a natural number multiple of the long side of the exposure area, twice in the present embodiment). Therefore, the exposure area 168 in the first row ₁₁ And exposure area 168 ₁₂ The portion that cannot be exposed between the two can be exposed by the exposure area 16821 in the second row and the exposure area 16831 in the third row.
[0026]
As shown in FIGS. 4 and 5A, each of the exposure heads 16611 to 166mn 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 is provided. The DMD 50 is connected to a controller (not shown) including a data processing unit and a mirror drive control unit. The data processing unit of this controller 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 in 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.
[0027]
As shown in FIG. 4, the exposure head 166 is provided with an illumination unit 144 on the light incident side of the DMD 50. The illumination unit 144 includes a fiber array light source 66 having a laser emission portion in which emission ends (light emitting points) of optical fibers are arranged in a line along a direction corresponding to the long side direction of the exposure area 168, a fiber array A lens system 67 that corrects laser light emitted from the light source 66 and collects the light 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.
[0028]
As shown in FIG. 6, the DMD 50 is configured such that a micromirror 62 is supported by a support column on an SRAM cell (memory cell) 60, and a large number of (pixels) (pixels) are formed. For example, the mirror device is configured by arranging 600 × 800 micromirrors 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.
[0029]
As shown in FIG. 7, each micromirror 62 has a hole-like non-reflective portion 62 </ b> A at the center of the reflective surface. Thereby, the reflected light image formed by the micromirror 62 has a light amount distribution in the vicinity of the center thereof that is not uniform. The reflectance of the micromirror 62 is 90% or more. A silicon gate CMOS SRAM cell 60 manufactured on a normal semiconductor memory manufacturing line is disposed directly below the micromirror 62 via a support including a hinge and a yoke, and is entirely monolithic (integrated type). ).
[0030]
When a digital signal is written in the SRAM cell 60 of the DMD 50, the micromirror 62 supported by the support is inclined within a range of ± α degrees (for example, ± 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. 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 inclination of the micromirror 62 in each pixel of the DMD 50 as shown in FIG. 6 according to the image signal, the light incident on the DMD 50 is reflected in the inclination direction of each micromirror 62. .
[0031]
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 a controller (not shown) connected to the DMD 50. Here, the light reflected by the micromirror 62 in the on state is modulated into an exposure state, and enters a projection optical system 146 (see FIG. 5) provided on the light exit side of the DMD 50. The light reflected by the micromirror 62 in the off state is modulated to the non-exposure state and enters a light absorber (not shown).
[0032]
Further, it is preferable that the DMD 50 is disposed slightly inclined so that the short side direction forms a predetermined angle θ (for example, 0.1 ° to 0.5 °) with the 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.
[0033]
In the DMD 50, a number of micromirror arrays in which a large number (for example, 800) of micromirrors are arranged along the longitudinal direction (row direction) are arranged in a short direction (for example, 600 sets). As shown in FIG. 8B, the pitch P of the scanning trajectory (scanning line) of the exposure beam 53 by each micromirror is obtained by inclining the DMD 50. ₁ However, the pitch P of the scanning line when the DMD 50 is not inclined. ₂ It becomes narrower and the resolution can be greatly improved. On the other hand, since the tilt angle of the DMD 50 is very small, the scanning width W when the DMD 50 is tilted. ₂ And the scanning width W when the DMD 50 is not inclined. ₁ Is substantially the same.
[0034]
Further, substantially the same position (dot) on 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, the joints between the plurality of exposure heads arranged in the scanning direction can be connected without any step by controlling a very small amount of exposure position.
[0035]
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 scanning direction instead of inclining the DMD 50.
[0036]
For example, as shown in FIG. 9A, the fiber array light source 66 includes a plurality of (for example, six) laser modules 64, and one end of the multimode optical fiber 30 is coupled to each laser module 64. Has been. The other end of the multimode optical fiber 30 is coupled with an optical fiber 31 having the same core diameter as the multimode optical fiber 30 and a cladding diameter smaller than the multimode optical fiber 30, as shown in FIG. A laser emission portion 68 is configured by arranging emission ends (light emission points) of the optical fiber 31 in a line along a direction orthogonal to the scanning direction. As shown in FIG. 9D, the light emitting points can be arranged in two rows along a direction orthogonal to the scanning direction. Such an arrangement of the emission end portions of the optical fiber 31 is determined based on the spot shape of the beam spot projected onto the exposure surface 56, as will be described later.
[0037]
As shown in FIG. 9B, the emission end of the optical fiber 31 is sandwiched and fixed between two support plates 65 having a flat surface. Further, a transparent protective plate 63 such as glass is disposed on the light emitting side of the optical fiber 31 in order to protect the end face of the optical fiber 31. The protection plate 63 may be disposed in close contact with the end surface of the optical fiber 31 or may be disposed so that the end surface of the optical fiber 31 is sealed. The exit end of the optical fiber 31 is easily deteriorated because it has a high light density and easily collects dust. However, by providing the protective plate 63, it is possible to prevent the dust from adhering to the end face and to delay the deterioration. .
[0038]
In the example of FIG. 9B, in order to arrange the emission ends of the optical fibers 31 with a small cladding diameter in a line without any gap, a multi-mode optical fiber 30 adjacent to each other with a large cladding diameter is arranged between The optical fibers 31 are stacked, and the output ends of the optical fibers 31 coupled to the stacked multimode optical fibers 30 are coupled to the two adjacent multimode optical fibers 30 at the portion where the cladding diameter is large. Are arranged so as to be sandwiched between the emission ends of the two.
[0039]
For example, as shown in FIG. 10, an optical fiber 31 having a length of 1 to 30 cm and having a small cladding diameter is coaxially connected to the tip of the multimode optical fiber 30 having a large cladding diameter on the laser light emission side. Can be obtained by linking them together. The two optical fibers 30 and 31 are fused and joined so that the incident end face of the optical fiber 31 is coincident with the outgoing end face of the multimode optical fiber 30 so that the central axes of both optical fibers 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.
[0040]
In addition, a short optical fiber in which an optical fiber having a short cladding diameter and a large cladding diameter is fused to an optical fiber having a short cladding diameter and a large cladding diameter may be coupled to the output end of the multimode optical fiber 30 via a ferrule or an optical connector. Good. By detachably coupling using a connector or the like, the tip portion can be easily replaced when an optical fiber having a small cladding diameter is broken, and the cost required for exposure head maintenance can be reduced. Hereinafter, the optical fiber 31 may be referred to as an emission end portion of the multimode optical fiber 30.
[0041]
The multimode optical fiber 30 and the optical fiber 31 may be any of a step index type optical fiber, a graded index type optical fiber, and a composite type optical fiber. For example, a step index type optical fiber manufactured by Mitsubishi Cable Industries, Ltd. can be used. In the present embodiment, 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 = 25 μm, NA = 0.2, an incident end face. The transmittance of the coat is 99.5% or more, and the optical fiber 31 has a cladding diameter = 60 μm, a core diameter = 25 μm, and NA = 0.2.
[0042]
In general, in laser light in the infrared region, propagation loss increases as the cladding diameter of the optical fiber is reduced. For this reason, a suitable cladding diameter is determined according to the wavelength band of the laser beam. However, the shorter the wavelength, the smaller the propagation loss. In the case of laser light having a wavelength of 405 nm emitted from a GaN-based semiconductor laser, the cladding thickness {(cladding diameter−core diameter) / 2} is set to infrared light in the wavelength band of 800 nm. The propagation loss hardly increases even if it is about ½ of the case of propagating infrared light and about ¼ of the case of propagating infrared light in the 1.5 μm wavelength band for communication. Therefore, the cladding diameter can be reduced to 60 μm.
[0043]
However, the cladding diameter of the optical fiber 31 is not limited to 60 μm. The clad diameter of an optical fiber used in a conventional fiber light source is 125 μm, but the depth of focus becomes deeper as the clad diameter becomes smaller. Therefore, the clad diameter of a multimode optical fiber is preferably 80 μm or less, more preferably 60 μm or less. Preferably, it is 40 μm or less. On the other hand, since the core diameter needs to be at least 3 to 4 μm, the cladding diameter of the optical fiber 31 is preferably 10 μm or more.
[0044]
The laser module 64 is configured by a combined laser light source (fiber light source) shown in FIG. This 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, arrayed and fixed on the heat block 10. And LD7, collimator lenses 11, 12, 13, 14, 15, 16, and 17 provided corresponding to each of the GaN-based semiconductor lasers LD1 to LD7, one condenser lens 20, and one multi-lens. Mode optical fiber 30. The number of semiconductor lasers is not limited to seven.
[0045]
The GaN-based semiconductor lasers LD1 to LD7 all have the same oscillation wavelength (for example, 405 nm), and the maximum output is also all the same (for example, 100 mW for the multimode laser and 30 mW for the single mode laser). As the GaN-based semiconductor lasers LD1 to LD7, lasers having an oscillation wavelength other than the above 405 nm in a wavelength range of 350 nm to 450 nm may be used.
[0046]
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. After the degassing process, a sealing gas is introduced, and the package 40 and the package lid 41 are closed by closing the opening of the package 40 with the package lid 41. 41. The combined laser light source is hermetically sealed in a sealed space formed by 41.
[0047]
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.
[0048]
Further, a collimator lens holder 44 is attached to the side surface of the heat block 10, and the collimator lenses 11 to 17 are held. 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.
[0049]
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. doing.
[0050]
FIG. 14 is a front view of the collimator lenses 11 to 17 and their mounting portions. 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).
[0051]
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 each of the laser beams B1 in a state parallel to the active layer and a divergence angle in a direction perpendicular to the active layer, respectively, for example 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.
[0052]
Accordingly, 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 f = 3 mm, NA = 0.6, and a lens arrangement pitch = 1.25 mm.
[0053]
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. This condensing lens 20 is also formed by molding resin or optical glass, for example.
[0054]
Next, the projection optical system 146 provided on the DMD 50 light reflection side of the exposure head 166 will be described. As shown in FIG. 5, the exposure head 166 is provided with a projection optical system 146 for projecting a light source image on the exposure surface 56 on the light reflection side of the DMD 50. In the projection optical system 146, a pair of lens systems 54 and 58, a microlens array 72, an aperture array 76, and a pair of lens systems 80 and 82 are arranged in this order from the DMD 50 side to the exposure surface 56.
[0055]
Here, the lens systems 54 and 58 are configured as a magnifying optical system (first optical system), and are reflected by the DMD 50 on the exposure surface 56 by enlarging the cross-sectional area of the light beam reflected by the DMD 50. The area of the exposure area 168 by the light beam is expanded to a required size. The microlens array 72 is formed by integrally forming a plurality of first microlenses 74 that correspond one-to-one to each micromirror 62 of the DMD 50 that reflects light from the illumination unit 144. 74 are arranged on the optical axis of the laser beam transmitted through the lens systems 54 and 58, respectively. The aperture array 76 is provided with a plurality of apertures (restriction openings) 76 that correspond one-to-one to the plurality of first microlenses 74 in the microlens array 72.
[0056]
In the projection optical system 146, the focal length of the lens system 54 is f1, and the focal length of the lens system 58 is f2. Each micromirror 62 of the DMD 50 is disposed at the front focal position of the lens system 54. The lens systems 54 and 58 are respectively disposed at confocal positions sharing the front focal position, and the microlens array 72 is disposed at the rear focal position of the lens system 58. Therefore, each micromirror 62 and the first microlens 74 are conjugated with each other. The focal length of the first microlens 74 is f3, and the aperture array 76 is disposed at the rear focal position of the first microlens 74. Thereby, the first microlens 74 and the aperture 78 constitute a telecentric optical system, and the light beam passing through the center of each aperture 78 is the light of the lens systems 54 and 58 and the first microlens 74 on the image side (exposure surface 56 side). Parallel to the axis. The lens systems 80 and 82 are configured as, for example, equal-magnification optical systems, and connect a real image group, which is a set of real images of the light source 68 formed by the plurality of first microlenses 74, on the exposure surface 56. Image. Here, the focal length of the lens system 80 is f4, and the focal length of the lens system 82 is f5. Each aperture 78 in the aperture array 76 is disposed at the front focal position of the lens system 80, and the lens systems 80 and 82 are respectively disposed at confocal positions sharing the front focal position. The exposure surface 56 is adjusted to the rear focal position of the lens system 82. Therefore, each aperture 78 and the exposure surface 56 are conjugate with each other. The lens systems 54 and 58 and the lens systems 80 and 82 in the projection optical system 146 are shown as one lens in FIG. 5, but a plurality of lenses (for example, a convex lens and a concave lens) are combined. It may be.
[0057]
In the projection optical system 146, the spot diameter and spot shape of the beam spot projected onto the exposure surface 56 are the resolution of the exposure pattern formed in the exposed area 170, the scanning speed of the exposure head 166, and the tilt angle of the DMD 50 with respect to the scanning direction. The size is determined according to the design items such as the characteristics of the photosensitive material 150. On the other hand, the aperture diameter and the aperture shape of the aperture 78 are set according to the spot diameter and spot shape of the beam spot projected onto the exposure surface 56. The focal length f3 of the first microlens 74 is set according to the aperture diameter of the aperture 78.
[0058]
The operation of the first microlens 74 in the projection optical system 146 will be described with reference to FIG. The lens systems 54 and 58 constituting the magnifying optical system enlarge the area of the exposure area 168 on the exposure surface 56 to a required size by enlarging the cross-sectional area of the light beam reflected by the DMD 50. At this time, the laser beam reflected by the micromirror 62 of the DMD 50 is also transmitted through the lens systems 54 and 58, so that the beam diameter is expanded according to the magnification of the lens systems 54 and 58. Therefore, when the microlens array 72 and the aperture array 76 are not arranged in the projection optical system 146, the spot diameter of each beam spot BS projected on the exposure surface 56 is the exposure as shown in FIG. It becomes large according to the size of the area 168. For this reason, even when scanning exposure is performed as shown in FIG. 8A, the MTF (Modulation Transfer Function) characteristics of the exposure area 168 are lowered in accordance with the magnification ratio of the lens systems 54 and 58.
[0059]
In order to prevent the above-described deterioration of the MTF characteristics, the projection optical system 146 includes the first microlens 74 having a positive lens power at the back focal position of the lens system 58 on the micromirror 62 of the DMD 50 on a one-to-one basis. It is arranged to correspond. The first microlens 74 reduces the beam diameter of the laser beam expanded by the lens systems 54 and 58. As a result, as shown in FIG. 5C, even when the exposure area 168 is enlarged by the lens systems 54 and 58 at a high magnification, the spot diameter of the beam spot BS can be reduced to a required size, and the exposure surface can be reduced. The deterioration of the MTF characteristic at 56 can be prevented.
[0060]
Next, a method for setting the focal length f3 of the first microlens 74 will be specifically described. As shown in FIG. 15, when the size (diameter) of the reflected light image of the micromirror 62 formed at the rear focal position of the lens system 58 is 2R, the aperture diameter of the first microlens 74 is set to 2R, and the aperture The opening diameter of 78 is set to (2R / n). At this time, n is a reduction ratio of the aperture diameter of the aperture 78 with respect to the aperture diameter of the first microlens 74, and this n is determined based on the spot diameter of the beam spot BS.
[0061]
Consider a condition in which all light beams transmitted through the first microlens 74 theoretically pass through the aperture 78. At this time, if the spread angle of the light flux from the first microlens 74 toward the light source is αs, the spread angle αs can be obtained by the following equation (1).
[0062]
αs = (R / n) / f3 (1)
From the equation (1), the focal length f3 of the micro lens 74 is obtained by the following equation (2).
[0063]
f3 = (R / n) / αs (2)
When the focal length f3 of the first microlens 74 is set to a value calculated by the above equation (2), the light transmitted through the first microlens 74 is theoretically transmitted by the aperture 78 as shown in FIG. The light is emitted from the aperture 78 to the exposure surface 56 side without being shielded, that is, without causing light loss. However, the light transmitted through the first microlens 74 includes light that becomes noise components such as diffracted light due to aberration of the first microlens 74 and scattered light due to scattering, and the light that becomes such noise components is apertured. In actuality, a slight light loss is caused by the aperture 78. However, the focal length f3 obtained by the equation (2) is a theoretical optimum value for minimizing the light loss. For this reason, the exposure head 166 allows the aperture 78 to be disposed at a minute distance from the rear focal position of the first microlens 74 in consideration of the shaping of the beam spot BS by the aperture 78, the noise light removal capability, and the like. Is done.
[0064]
The spread angle of the light emitted from the aperture 78 when the focal length f3 of the microlens 74 is set according to the equation (2) as described above will be described. When attention is paid to the spread angle αb of the light passing through the center of the aperture 78, the following expression (3) is obtained.
[0065]
αb = R / f3
= R / {(R / n) / αs}
= N × αs (3)
As is clear from the above equation (3), the spread angle αb increases as the light bundle is reduced by the microlens 74 and the illumination area for the aperture 78 is reduced. The light spread angle at the opening end of the aperture 78 is larger than the light spread angle αb at the center of the aperture 78, and the relationship αc = αs is established, where αc is the increase in the spread angle. Therefore, the maximum spread angle αm of the light that has passed through the aperture 78 is obtained by the following equation (4).
[0066]
αm = αb + αc = (1 + n) αs (4)
Next, the relationship between the spot shape of the beam spot BS and the contour shape of the laser emitting portion 68 in the fiber array light source 66 will be described. As described above, in the projection optical system 146, the first microlens 74 is conjugate with the micromirror 62 via the lens systems 54 and 58, and the aperture 78 is disposed at the rear focal position of the first microlens 74. Yes. As a result, as shown in FIG. 16, a light source image LI of the laser emitting portion 68 is formed at the rear focal position and the aperture 78 of the lens system 54, respectively. Therefore, the projection optical system 146 projects the light source image formed on the aperture 78 onto the exposure surface 56 via the lens systems 80 and 82, and exposes the exposure surface 56 using this light source image as the beam spot BS.
[0067]
When the light source image of the laser emitting unit 68 is projected on the exposure surface 56 as the beam spot BS as described above, the outline shape of the beam spot BS and the outline shape along the direction perpendicular to the optical axis of the laser emitting unit 68 are roughly. Approximate. Therefore, if the contour shape of the laser emitting portion 68 along the direction perpendicular to the optical axis is approximated to the required spot shape of the beam spot BS, and the aperture shape of the aperture is substantially similar to the spot shape of the beam spot BS. Thus, the light loss when the laser beam emitted from the laser emitting portion 68 passes through the aperture 78 can be effectively suppressed.
[0068]
FIGS. 17A to 17C each show a configuration example of a laser emitting unit configured by bundling a plurality of optical fibers 31 in consideration of the spot shape of the beam spot BS. For example, when the beam spot BS is required to have a circular or hexagonal shape, as shown in FIG. 17A, the emission end portions of a plurality (six) of optical fibers 31 are arranged in a hexagonal fine pattern. A laser emitting portion 68 configured to be bundled in a filling shape has come. When the fiber array light source 66 is composed of a large number of optical fibers 31, the emission end portions of these optical fibers 31 are substantially hexagonal as shown in FIG. ) Can be bundled into an arbitrary shape such as a substantially rectangular shape.
[0069]
By the way, when the light bundle is reduced by the microlens 74, the spread angle (maximum spread angle αm) of the light bundle that has passed through the aperture 78 is increased. Here, since the focal depth of the beam spot BS on the exposure surface 56 becomes shallower as the spread angle of the light beam that has passed through the aperture 78 increases, it is preferable that the maximum spread angle of the light beam that has passed through the aperture 78 be smaller.
[0070]
18A and 18B show a configuration example in which the second microlens 84 is provided in the aperture array 76 so that the spread angle of the light beam that has passed through the aperture 78 is reduced. In the aperture array 76, as shown in FIG. 18B, a second microlens 84 is arranged inside each aperture 78, that is, at the rear focal position of the first microlens 74. The lens diameter of the second microlens 84 matches the aperture diameter (= 2R / n) of the aperture 78, and the focal length f6 of the second microlens 84 is the same as the focal length f3 of the first microlens 74 ( R / n) / αs.
[0071]
By disposing the second microlens 84 in each aperture 78 of the aperture array 76, the principal ray of each beam bundle that has passed through the aperture 78 is parallel to the optical axis, and the spread angle of the beam bundle that has passed through the aperture 78 is reduced. Increase can be suppressed. That is, when the second microlens 84 is added, the increase αc of the inclination of the light beam passing through the opening end of the aperture 78 becomes 0 °, and thus the maximum spread angle αm ′ of the light beam is expressed as (5 ).
[0072]
αm ′ = αb + αc
= Αb
= R / f3 = R / {(R / n) / αs}
= N × αs (5)
As is clear from comparison with the maximum spread angle αm obtained by the equation (4), when the second microlens 84 is disposed in the aperture 78, the maximum spread angle αm ′ is sufficiently small. Thereby, when the light source image is projected on the exposure surface 56 as the beam spot BS, the depth of focus of the beam spot BS can be increased.
[Operation of exposure apparatus]
Next, the operation of the exposure apparatus 142 will be described.
[0073]
In each exposure head 166 of the scanner 162, laser beams B1, B2, B3, B4, B5, B6 emitted in a divergent light state from each of the GaN-based semiconductor lasers LD1 to LD7 constituting the combined laser light source of the fiber array light source 66. , And B7 are collimated by collimator lenses 11-17 as shown in FIG. 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.
[0074]
In the present embodiment, a condensing optical system is configured by the collimator lenses 11 to 17 and the condensing lens 20, and a combining optical system is configured by the condensing optical system and the multimode optical fiber 30. That is, the laser beams B1 to B7 condensed 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.
[0075]
In each laser module 64, when the coupling efficiency of the laser beams B1 to B7 to the multimode optical fiber 30 is 0.85 and each output of the GaN-based semiconductor lasers LD1 to LD7 is 30 mW, as shown in FIG. A combined laser beam B having an output of 180 mW (= 30 mW × 0.85 × 7) can be obtained for each of the optical fibers 31 arranged in an array. Therefore, the output from the laser emitting unit 68 in which the six optical fibers 31 are arranged in an array is about 1 W (= 180 mW × 6).
[0076]
For example, in a conventional fiber light source in which a semiconductor laser and an optical fiber are coupled on a one-to-one basis, a laser having an output of about 30 mW (milliwatt) is usually used as the semiconductor laser, and the core diameter is 50 μm and the cladding diameter is 125 μm. Since a multimode optical fiber having a numerical aperture (NA) of 0.2 is used, if an output of about 1 W (watt) is to be obtained, 48 multimode optical fibers (8 × 6) must be bundled. The area of the light emitting region is 0.62 mm ² (0.675 mm × 0.925 mm), the luminance at the laser emitting portion 68 is 1.6 × 106 (W / m). ² ), The luminance per optical fiber is 3.2 × 106 (W / m ² ).
[0077]
On the other hand, in this embodiment, as described above, an output of about 1 W can be obtained with six multimode optical fibers, and the area of the light emitting region at the laser emitting portion 68 is 0.0081 mm. ² (0.325 mm × 0.025 mm), the luminance at the laser emitting portion 68 is 123 × 106 (W / m). ² Thus, the brightness can be increased by about 80 times compared to the conventional case. The luminance per one optical fiber is 90 × 106 (W / m ² The brightness can be increased by about 28 times compared to the conventional case. As a result, the angle of the light beam incident on the DMD 50 is reduced, and as a result, the angle of the light beam incident on the exposure surface 56 is also reduced, so that the focal depth of the beam spot can be increased.
[0078]
Image data corresponding to the exposure pattern is input to a controller (not shown) connected to the DMD 50 and temporarily stored in a frame memory in the controller. This image data is data representing the density of each pixel constituting the image by binary values (whether or not dots are recorded).
[0079]
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 a driving device (not shown). When the leading edge of the photosensitive material 150 is detected by the detection 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 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.
[0080]
When the DMD 50 is irradiated with laser light from the fiber array light source 66, the laser light reflected when the micromirror of the DMD 50 is on is imaged on the exposure surface 56 of the photosensitive material 150 by the lens systems 54 and 58. The 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, the photosensitive material 150 is moved at a constant speed together with the stage 152, so that the photosensitive material 150 is 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. Is done.
[0081]
When the 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 detection sensor 164, the stage 152 is moved to the most upstream side of the gate 160 along the guide 158 by a driving device (not shown). 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.
[0082]
In the exposure apparatus 142 described above, the first microlenses 74 are two-dimensionally arranged so as to correspond one-to-one with the micromirrors 62 in the DMD 50, and these microlenses 74 are brought into an exposure state by the micromirrors 62. Projecting a light source image, which is supported on the optical path of the modulated laser beam and formed at the rear focal position of the first microlens 74, onto the exposure surface 56, and exposes the exposure surface 56 using this light source image as a beam spot BS. As a result, the beam diameter of the laser beam modulated in the exposure state by each micro mirror 62 of the DMD 50 can be generated by the first micro lens 74, so that the area of the exposure area 168 is enlarged with respect to the surface portion of the DMD 50 by the lens systems 50 and 54. Even in such a case, the beam diameter of the beam spot BS projected on the exposure surface 56 is reduced. Doo becomes possible, it is possible to prevent deterioration of under MTF characteristics in the exposure area 168.
[0083]
Further, in the exposure apparatus 142, the light source image of the laser emitting unit 68 is projected onto the exposure surface 56, and the exposure surface 56 is exposed using this light source image as the beam spot BS, so the influence of the non-reflecting part 62A of the micromirror 62 in the DMD 50 Therefore, it is possible to prevent the light amount distribution at the center of the beam spot from being lowered, and the exposure surface 56 can be exposed by the beam spot BS having a uniform light amount distribution.
[0084]
In the exposure head 146 described above, in order to adjust the distance from the DMD 50 to the formation position of the beam spot BS, the lens systems 54 and 58 constituting the magnifying optical system and the equal-magnification optical system are constituted to form the lens system 80. , 82 are used, but when the distance from the DMD 50 to the exposure surface 56 is short, the lens systems 80, 82 are omitted and reduced by each first microlens 74 as shown in FIG. The exposed light source image of the laser emitting section 68 may be directly exposed to the exposure surface 56 as a beam spot BS. In this case, in the exposure apparatus 142, the position of the exposure surface 56 is adjusted near the rear focal position of each first microlens 72.
[0085]
However, as shown in FIG. 20A, when the light source image formed by the first microlens 72 is a direct beam spot BS, shaping of the contour shape of the beam spot BS, diffracted light, and flare light are performed. It is impossible to block light that becomes a noise component. In order to solve such a problem, as shown in FIG. 20B, an aperture array 90 is arranged in the vicinity of the rear focal position of the first microlens 72, and the exposure surface 56 is separated from the aperture array 90 by a predetermined distance. It is conceivable to adjust the position. The aperture array 90 is provided with a plurality of apertures 92 so as to face each first microlens 72 in the microlens array 72. The aperture diameter and the aperture shape of each aperture 92 are appropriately set according to the spot diameter and spot shape of the beam spot BS required on the exposure surface 56.
[0086]
Here, the distance D between the aperture array 90 and the exposure surface 56 has an optimum distance range according to the wavelength of the laser light and the aperture diameter of the aperture 92 in consideration of diffraction of light that has passed through the aperture 92. For example, when the wavelength of the laser beam is 405 nm and the aperture diameter of the aperture 92 is 13 μm, the distance D is set within a range of approximately 50 to 200 μm.
[0087]
Further, when the contour shape of the beam spot BS and noise components such as diffracted light and flare light are not a serious problem due to the characteristics of the photosensitive material 150, the aperture array 76 is connected to the projection optical system 146 as shown in FIG. May be omitted. Even in this case, it is possible to secure the basic effect that the MTF characteristics in the exposure region 156 can be prevented from being lowered and the light quantity distribution of the beam spot BS can be made uniform.
[0088]
In addition, in the exposure apparatus 142 according to the present embodiment, a DMD is used as a spatial modulation element. For example, a MEMS (Micro Electro Mechanical Systems) type spatial modulation element (SLM; Spatial Light Modulator) or transmission by an electro-optic effect. Even when a spatial modulation element other than the MEMS type such as an optical element (PLZT element) for modulating light or a liquid crystal optical shutter (FLC) is used in place of the DMD 50, the projection optical system 146 shown in FIG. 5 or FIG. Can be used to prevent the lowering of the MTF characteristics in the exposure area 168 while suppressing the light loss caused by the aperture 78.
[0089]
Note that MEMS is a general term for micro systems that integrate micro-sized sensors, actuators, and control circuits based on micro-machining technology based on the IC manufacturing process. It means a spatial modulation element that is driven by the electromechanical operation used.
[0090]
【The invention's effect】
As described above, according to the exposure head and the exposure apparatus of the present invention, it is possible to suppress a decrease in the utilization efficiency of the laser beam emitted from the laser emitting portion of the illumination means and to set the exposure surface to a desired spot diameter and spot shape. It can be exposed by the beam spot.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external appearance of an exposure apparatus according to a first embodiment.
FIG. 2 is a perspective view showing a configuration of a scanner of the exposure apparatus according to the first embodiment.
FIG. 3A is a plan view showing an exposed area formed on a photosensitive material, and FIG. 3B is a view showing an arrangement of exposure areas by each exposure head.
FIG. 4 is a perspective view showing a schematic configuration of an exposure head of the exposure apparatus according to the first embodiment.
5A is a side view showing the configuration of the exposure head shown in FIG. 4, and FIGS. 5B and 5C are plan views of an exposure area by the exposure head.
FIG. 6 is a partially enlarged view showing a configuration of a digital micromirror device (DMD).
7A and 7B are explanatory diagrams for explaining the operation of the DMD. FIG.
FIGS. 8A and 8B are plan views showing the arrangement of exposure beams and scanning lines in a case where the DMD is not inclined and in a case where the DMD is inclined. FIG.
9A is a perspective view showing the configuration of a fiber array light source, FIG. 9B is a partially enlarged view of A, and FIGS. 9C and 9D show the arrangement of light emitting points in a laser emitting section. FIG.
FIG. 10 is a diagram showing a configuration of a multimode optical fiber.
FIG. 11 is a plan view showing a configuration of a combined laser light source.
FIG. 12 is a plan view showing the configuration of a laser module.
13 is a side view showing the configuration of the laser module shown in FIG. 12. FIG.
14 is a partial side view showing the configuration of the laser module shown in FIG. 12. FIG.
15 is a side view showing a configuration of a first microlens and an aperture in the exposure head shown in FIG. 5. FIG.
16 is an enlarged view of the vicinity of the first microlens in the projection optical system shown in FIG.
FIGS. 17A, 17B, and 17C are front views showing a configuration example of a laser emitting unit in the exposure apparatus according to the first embodiment, respectively.
FIG. 18 is a side view showing a configuration example in which the second microlens is arranged in the aperture array in the exposure apparatus according to the first embodiment.
FIG. 19 is a side view along the optical axis showing the configuration of a conventional exposure head.
FIG. 20 is a side view showing the configuration of a modification of the exposure head according to the embodiment of the present invention.
FIG. 21 is a side view showing a configuration of an exposure head when an aperture array is omitted from the projection optical system shown in FIG.
[Explanation of symbols]
30 Multimode optical fiber
50 DMD (Spatial Light Modulator)
54, 58 Lens system (first optical system)
56 Exposure surface
62 Micromirror (pixel part)
68 Laser emitting part
72 Micro lens array
74 First microlens
76 Aperture Array
78 Aperture
80, 82 Lens system (second optical system)
84 Second micro lens
142 Exposure equipment
144 Illumination unit (illumination means)
146 Projection optical system
166 Exposure head

Claims (6)

An exposure head for two-dimensionally exposing an exposure surface with a plurality of laser beams,
An illumination means for emitting a laser beam from the laser emitting section;
A plurality of pixel portions whose light modulation states change according to the control signal are two-dimensionally arranged, and the laser beam incident from the laser emitting portion is modulated by the pixel portion into either an exposure state or a non-exposure state. A spatial light modulation element,
A first optical system that forms an image of each pixel portion in the spatial light modulator;
A plurality of first microlenses that are two-dimensionally arranged so as to correspond to the plurality of pixel portions, and are respectively supported at imaging positions of the plurality of pixel portions;
An exposure head, wherein a light source image of the laser emitting portion formed at a rear focal position of the first microlens is projected onto the exposure surface, and the exposure surface is exposed using the light source image as a beam spot. 2. The exposure according to claim 1, further comprising: a second optical system that forms a light source image group, which is a set of light source images formed by the plurality of first microlenses, on the exposure surface. head. 3. The exposure according to claim 1, wherein an aperture having an aperture diameter and an aperture shape corresponding to the spot diameter and spot shape of the beam spot on the exposure surface is disposed in the vicinity of the back focal position of the first microlens. head. 4. The exposure head according to claim 3, wherein a second microlens having a positive lens power is disposed at a rear focal position of the first microlens. 5. The exposure head according to claim 1, wherein a contour shape along a direction perpendicular to the optical axis in the laser emitting portion is a shape corresponding to a shape of a beam spot on the exposure surface. The exposure head according to claim 1, 2, 3, 4 or 5,
Moving means for supporting the exposure head so that an arrangement direction of the plurality of pixel portions is inclined with respect to a scanning direction with respect to the exposure surface, and relatively moving the exposure head in the scanning direction when exposing the exposure surface;
An exposure apparatus comprising:

Images