JP4486323B2 - Pixel position specifying method, image shift correcting method, and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus and an image misalignment correction method, and more particularly, to an image misalignment capable of forming a high-quality image that is inconspicuous by changing the relative position between exposure heads in an image forming apparatus having a plurality of exposure heads The present invention relates to a correction method and an image forming apparatus that corrects an image shift between exposure heads by the image shift correction method.
[0002]
[Prior art]
Conventionally, as an example of an image recording apparatus, there has been an exposure apparatus that uses a spatial light modulation element (SLM) such as a digital micromirror device (DMD) and performs image exposure with a light beam modulated according to image data. Various proposals have been made (see, for example, Non-Patent Documents 1 and 2). This DMD is configured by, for example, a large number of micro-mirrors provided on each memory cell of the SRAM, and changes the angle of the reflection surface of the micro-mirror by electrostatic force due to electric charges stored in each memory cell. When actual drawing is performed, each micromirror is reset to a predetermined angle while image data is written in each SRAM, and the light reflection direction is set to a desired direction.
[0003]
One application field of the exposure apparatus is, for example, the manufacture of panels such as liquid crystal displays and printed boards.
[0004]
As an exposure apparatus for manufacturing a panel or a printed circuit board, a multi-head exposure in which a plurality of exposure heads having the DMD are arranged along a direction intersecting a feeding direction of a photosensitive material such as the substrate for the purpose of expanding an exposure range. There is a device.
[0005]
In the multi-head exposure apparatus, the relative positions between the heads are adjusted with high accuracy to such an extent that the joints do not become a practical problem.
[0006]
[Non-Patent Document 1]
Larry J. Hornbeck, Digital Light Processing and MEMS: reflecting the digital display needs of the networked society, THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING, Proceedings of SPIE Volume: 2783, 8/1996, P.2-13
[Non-Patent Document 2]
WENelson and Robit L Bhuva, .Digital micromirror device imaging bar for hard copy, THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING, Proceedings of SPIE Volume: 2413, 4/1995, P.58-65
[Patent Document 1]
Japanese Patent Laid-Open No. 10-31170
[0007]
[Problems to be solved by the invention]
However, in recent years, as the degree of integration of the substrates has increased, higher resolution has been required, so that the allowable value of the relative position shift of the image corresponding to each exposure head has decreased.
[0008]
Furthermore, in the exposure head, since many optical members and mechanism members are used from the light source to the imaging surface, thermal expansion and contraction due to temperature change, and accumulation of changes over time due to long-term use. As a result, there is a problem that the image formed by each exposure head causes a shift that cannot be ignored at the joint, and the image quality is deteriorated.
[0009]
In a multi-beam exposure apparatus used for the same purpose as the multi-head exposure apparatus, the position of each beam is detected by a position detection element such as a PSD (position-sensing device) or a quadrant detector, A method for correcting a shift between images formed by a beam has been proposed (Patent Document 1).
[0010]
However, in the multi-head exposure apparatus, the interval between exposure heads is overwhelmingly larger than the interval between adjacent beams, so it is difficult to apply the method described in Patent Document 1 to the multi-head exposure apparatus.
[0011]
The present invention has been made to solve the above-described problem. In the multi-head exposure apparatus, an exposure apparatus in which a deviation between images formed by each exposure head is extremely small and an image deviation that can be performed by the exposure apparatus. An object is to provide a correction method.
[0012]
[Means for Solving the Problems]
The invention according to claim 1 is an image forming apparatus that forms an image by scanning a plurality of exposure heads having a means for selectively turning on / off a plurality of pixels in a predetermined direction. A pixel position specifying method for measuring a position and specifying a pixel position of a joint of the exposure head, wherein the pixel position specifying method is configured to be movable on a reference plane along a Y-axis direction parallel to the scanning direction, And at least one pair of slit portions arranged obliquely with respect to the pixel array of the exposure head and intersecting each other, and a light amount measuring means for measuring the light amount of the exposure beam transmitted through the slit portion. The position of the exposure beam is measured using the beam position detection means having the first specific pixel near the joint of the image in the first exposure head, and the beam position detection means is set to Y. The position of the beam position detection means, the position of the slit portion, and the angle formed by the slit portion when the light amount of the exposure beam transmitted through one and the other of the slit portions reaches a peak. A first pixel position specifying step for specifying the position of the first specific pixel based on the second specific pixel, and turning on the second specific pixel in the vicinity of the joint of the image in the second exposure head to move the beam position detecting means in the Y-axis direction. And the second specific pixel based on the angle formed by the position of the beam position detecting means and the slit portion when the light amount of the exposure beam that passes through one and the other of the slit portions reaches a peak. And a second pixel position specifying step for specifying the position of the pixel position.
[0013]
In the pixel position specifying method, as described above, the beam position detection in which at least one pair of slit portions that are relatively oblique to the pixel array of the exposure head and that intersect with each other is formed. The means is moved in the Y-axis direction to detect the first specific pixel and the second specific pixel.
[0014]
For example, when the beam position detection means passes below the first specific pixel, the light amount of the exposure beam that passes through one of the pair of slits reaches a peak, and then passes through the other of the pair of slits. The light intensity of the exposure beam to reach the peak.
[0015]
Therefore, the position of the beam position detection means when the transmitted light amount of the exposure beam reaches the peak in the one slit portion, and the beam position when the transmitted light amount of the exposure beam reaches the peak in the other slit portion. The position of the first specific pixel can be specified based on the position of the detection means and the angle formed by the one and the other slit portions. The same applies to the second specific pixel. Here, as the position of the beam position detecting means, the position of a specific point on the beam position detecting means can be taken, but usually the position of the intersection of the slit portions is used as a reference.
[0016]
Further, since the exposure beam is normally irradiated from the exposure head at a right angle to the reference plane, when a pixel with the exposure head is turned on, the irradiation position of the exposure beam on the reference plane becomes equal to the position of the pixel. . Therefore, in the first pixel position specifying step and the second pixel position specifying step, the position of the exposure beam detected by the beam position detecting means can be set as the position of the first or second specific pixel.
[0017]
According to the pixel position specifying method, the actual positions of the first specific pixel and the second specific pixel can be specified with high accuracy in this way. Accordingly, even when a positional deviation occurs between the first exposure head and the second exposure head for some reason, the positions of the first specific pixel and the second specific pixel specified by the pixel position specifying method are based on the positions. Further, by controlling the exposure timing of the exposure heads, it is possible to remove image shifts and overlaps between the exposure heads.
[0018]
In the pixel position specifying method, a normal light receiving element is sufficient because the light amount measuring unit only needs to be able to measure the light amount of the exposure beam that passes through the slit portion. Therefore, since it is not necessary to use an expensive position detection element such as a two-dimensional PSD or a quadrant detector for detecting the position of the exposure beam, the beam position detection means can be configured at low cost.
[0019]
Further, the multi-head exposure apparatus described in the section of the prior art usually has an exposure stage on which a substrate to be exposed is placed and sent in a fixed direction, and the exposure stage is highly accurate by a linear encoder or the like. The feed direction, that is, the position in the Y-axis direction is detected.
[0020]
Therefore, if the beam position detection means is fixed to the non-exposure surface of the exposure stage, and the position is detected by the linear encoder while the exposure stage is fed in the feed direction, the position of the beam position detection means is also highly accurate. Since it can be detected, the actual positions of the first specific pixel and the second specific pixel can also be specified with high accuracy.
[0021]
As described above, the pixel position specifying method has a feature that the position of the first specific pixel and the second specific pixel can be specified with high accuracy by using a conventional multi-head exposure apparatus almost as it is.
[0022]
Further, according to the pixel position specifying method, the beam position detecting means is moved along the Y-axis direction, that is, the scanning direction, the first specific pixel and the second specific pixel are selected, and the position is specified. A pixel having a small difference in X coordinate with the first specific pixel can be selected as the two specific pixels.
[0023]
Therefore, the image shift between the first exposure head and the second exposure head can be eliminated simply by controlling the exposure timing of the first specific pixel and the second specific pixel to remove the shift in the Y-axis direction. .
[0024]
As the slit portion, a diffraction grating can be used in addition to the slit.
[0025]
In the pixel position specifying method, the beam position detecting unit may be arranged in a V shape, an X shape, or a T shape that opens the slit portion in the X-axis direction.
[0026]
According to a second aspect of the present invention, there is provided an image forming apparatus for forming an image by scanning a plurality of exposure heads having means for selectively turning on / off a plurality of pixels in a predetermined direction. A pixel position specifying method for measuring a position and specifying a pixel position of a joint of the exposure head, wherein the pixel position is relatively inclined with respect to a pixel array of the exposure head, and one is in a scanning direction of the exposure apparatus The amount of the exposure beam transmitted through the slit portion and at least one pair of slit portions disposed along the X-axis direction perpendicular to the Y-axis direction and disposed along the Y-axis parallel to the other. The position of the exposure beam is measured using a beam position detection means having a light quantity measurement means for measuring, and the pixels near the joint of the image in the first exposure head are sequentially turned on to detect the beam position. The pixel position when the light amount of the exposure beam passing through one of the slit portions reaches a peak in the stage, and the light amount of the exposure beam passing through the other of the slit portions in the beam position detecting means A first pixel position specifying step for specifying the position of the first specific pixel from the pixel position and the difference between the Y coordinates of the two pixels; and a second position by moving the beam position detecting means along the Y-axis direction. The exposure head is positioned below the joint of the image, and the pixels of the second exposure head are sequentially turned on, and the light amount of the exposure beam passing through one of the slit portions reaches the peak in the beam position detecting means. The pixel position when the light amount of the exposure beam passing through the other of the slits in the beam position detection means reaches a peak, About the pixel location method which is characterized in that a second pixel position specifying step of specifying a position of the second specific pixel from the difference between the Y coordinates of the two pixels.
[0027]
In the pixel position specifying method, one of the slit portions of the beam position detecting means is disposed along the Y-axis direction and the other is disposed along the X-axis direction, and is inclined with respect to the pixel array of the exposure head. is doing.
[0028]
The pixels in the vicinity of the joint of the first exposure head are sequentially turned on in the row direction to detect the light amount of the exposure beam that passes through the slit portion along the Y-axis direction. The selected pixel is selected as the first specific pixel. Then, the pixels in the vicinity of the first specific pixel are sequentially turned on along the column direction, the amount of exposure beam passing through the slit portion along the X-axis direction is measured, and when the amount of light reaches a peak The lit pixel is selected as an auxiliary pixel for specifying the position of the first specific pixel in the Y-axis direction.
[0029]
When the first specific pixel and the auxiliary pixel are selected, the Y coordinate of the first specific pixel is specified from the Y coordinate of the auxiliary pixel and the difference between the Y coordinates of the auxiliary pixel and the first specific pixel.
[0030]
Next, if necessary, the beam detecting means is moved in the Y-axis direction, pixels in the vicinity of the joint of the second exposure head are sequentially lit in the row direction, and the same procedure as in the case of the first specific pixel is performed. 2 specific pixels and an auxiliary pixel for specifying the position of the first specific pixel in the Y-axis direction are selected, and the Y coordinate of the auxiliary pixel and the difference between the Y coordinates of the auxiliary pixel and the second specific pixel are determined. The Y coordinate of the second specific pixel is specified.
[0031]
In addition to the features of the pixel position specifying method according to claim 1, the pixel position specifying method includes an exposure beam without moving the beam position detecting means in the first pixel position specifying step and the second pixel position specifying step. It has the feature that the position of can be specified.
[0032]
Further, since the beam position detecting means only moves along the Y-axis direction, the X coordinates of the first specific pixel and the second specific pixel are the same. Therefore, the first exposure head and the first exposure head can be controlled only by controlling the exposure timing of the first and second exposure heads according to the distance between the first specific pixel and the second specific pixel along the Y-axis direction and the scanning speed. It is possible to eliminate image shift and overlap between the two exposure heads.
[0033]
The slit portion is as described in claim 1.
[0034]
According to a third aspect of the present invention, there is provided an image forming apparatus for forming an image by scanning a plurality of exposure heads having means for selectively turning on / off a plurality of pixels in a fixed direction. A pixel position specifying method for measuring a position and specifying a pixel position of a joint of the exposure head, wherein the pixel position specifying method is formed to be movable along a Y-axis direction and an X-axis direction on a reference plane, and is long in the Y-axis direction. The exposure is performed using a beam position detecting unit having a first slit unit, a second slit unit that is long in the X-axis direction, and a light amount measuring unit that measures a light amount of the exposure beam that passes through the first and second slit units. The position of the beam is measured, the first specific pixel near the joint of the image in the first exposure head is turned on, the beam position detecting means is moved in the X-axis direction and the Y-axis direction, and the first slit is moved. A first pixel position specifying step for specifying the position of the first specific pixel based on the position of the beam position detecting means when the amount of light of the exposure beam passing through the first slit portion and the second slit portion reaches a peak; The second specific pixel near the joint of the image in the exposure head of No. 2 is turned on, the beam position detecting means is moved in the X-axis direction and the Y-axis direction, and transmitted through the first slit portion and the second slit portion. And a second pixel position specifying step for specifying the position of the second specific pixel based on the position of the beam position detecting means when the amount of light of the exposure beam reaches a peak. .
[0035]
In the pixel position specifying method, in the first and second pixel position specifying steps, the beam position detecting means is moved in the X-axis direction to detect the exposure beam in the first slit portion, thereby the first and second pixel position specifying steps. The position of the specific pixel and the second specific pixel in the X-axis direction is obtained, the beam position detecting means is moved in the Y-axis direction, and the exposure beam is detected in the second slit portion, whereby the first specific pixel and the second specific pixel are detected. The position of the second specific pixel in the Y-axis direction is obtained.
[0036]
According to the pixel position specifying method, even when the first specific pixel and the second specific pixel are separated in both the X-axis direction and the Y-axis direction, the actual positions of both can be accurately specified. By controlling the first and second exposure heads so that the images are connected by the first specific pixels and the second specific pixels, it is possible to remove the image shift.
[0037]
As the beam position detecting means that can be used in the pixel position specifying method, for example, a non-exposed surface of an exposure stage of a multi-exposure head has a base that can be moved with high precision in the X-axis direction, and a base by a linear encoder head. And a beam detecting device in which the first slit portion and the second slit portion are provided on the base.
[0038]
The method according to claim 4 is an image shift correction method for correcting image shift and overlap between exposure heads in an image forming apparatus that forms an image with a plurality of exposure heads scanned in a fixed direction. The pixel position specifying method according to any one of claims 1 to 3, wherein the first specific pixel in the vicinity of the joint of the image in the first exposure head and the first in the vicinity of the joint of the image in the second exposure head. A pixel position specifying step for specifying the position of two specific pixels; and the first specific pixel and the second specific pixel based on the positions of the first specific pixel and the second specific pixel specified in the pixel position specifying step. And an image data correction step for correcting image data input to the first exposure head and the second exposure head so that the images are connected to each other. About.
[0039]
In the image shift correction method, the actual positions of the first specific pixel and the second specific pixel are specified in the pixel position specifying step.
[0040]
Then, in the image data correction step, the image is connected between the first specific pixel and the second specific pixel based on the difference in position between the first specific pixel and the second specific pixel specified in the pixel position specifying step. As described above, the image data input to the first exposure head and the second exposure head are corrected.
[0041]
Therefore, according to the pixel position specifying method, even when the first exposure head and the second exposure head deviate from their positions for some reason, the image at the joint portion of the exposure head caused by the misalignment. Can be effectively removed.
[0042]
According to a fifth aspect of the present invention, in the image data correction step, regarding the shift in the Y-axis direction between the first specific pixel and the second specific pixel, the first specific pixel and the second specific pixel And the exposure timing of the first exposure head and the second exposure head in accordance with the distance in the Y-axis direction between the first exposure head and the scanning speed of the exposure head. Regarding the shift in the X-axis direction between the pixel and the second specific pixel, the first exposure head and the second exposure head so that image data overlaps the first specific pixel and the second pixel. The present invention also relates to an image shift correction method for removing image data by inputting image data.
[0043]
In the pixel position specifying method according to claim 1 or 2, since the second pixel is detected by moving the beam position detecting unit that detects the first specific pixel in the Y-axis direction, the first specific pixel and the first specific pixel are detected. Although the two specific pixels have different positions on the Y coordinate, the positions on the X coordinate are substantially equal.
[0044]
Therefore, when the image data is input to the first exposure head and the second exposure head so that the image data overlaps the first specific pixel and the second pixel, a shift in the Y-axis direction occurs. If the exposure timings of the first exposure head and the second exposure head are set so that there is no deviation, it is possible to eliminate image shift and overlap between the first specific pixel and the second pixel.
[0045]
According to the sixth aspect of the present invention, the position of the connecting pixel in each image head on the reference plane is specified by the pixel position specifying step for three or more exposure heads, and the images are connected by the connecting pixels. The present invention also relates to an image shift correction method for correcting image data input to each of the exposure heads based on a city of connected pixels specified by the pixel position specifying step.
[0046]
The image shift correction method according to claim 6 or 7, wherein an image forming apparatus having a plurality of exposure heads is used to correct an image misalignment between one exposure head and another exposure head connected to the one exposure head. By correcting image misalignment and overlap, a high-quality image without misalignment or overlap between exposure heads is formed.
[0047]
The invention described in claim 7 includes means for selectively turning on / off a plurality of pixels, and also includes a plurality of exposure heads that form an image by exposing while scanning the image forming surface in a certain direction. Exposure means and beam position detection means for detecting the position of the exposure beam of each exposure head, wherein the exposure head is formed to be movable on a reference plane along a Y-axis direction parallel to the scanning direction. A beam having at least one pair of slit portions disposed so as to be oblique to each other and intersecting each other, and a light amount measuring means for measuring the light amount of the exposure beam transmitted through the slit portions. A position detecting unit, a pixel position specifying unit for specifying a position of a pixel of the exposure head based on the exposure beam position detected by the beam position detecting unit, and the pixel position specifying unit. Exposure control means for controlling the exposure head based on the determined pixel position, wherein the pixel position specifying means is configured to detect a first specific pixel in the vicinity of the joint of the image in the first exposure head in the exposure means. the beam position when the beam position detecting means is moved along the Y-axis direction and the light quantity of the exposure beam that passes through one and the other of the slit portions of the beam position detecting means reaches a peak. The position of the first specific pixel is specified based on the position of the detection means and the angle formed by the slit portion, and the second specific pixel near the joint of the image in the second exposure head is turned on in the exposure means. The beam position detecting means is moved along the Y-axis direction, and the dew that passes through one and the other of the slit portions of the beam position detecting means is provided. The position of the second specific pixel is specified based on the position of the beam position detection means when the light amount of the beam reaches a peak and the angle formed by the slit portion, and the exposure control means is configured to detect the beam position detection means. Based on the positions of the first specific pixel and the second specific pixel specified in Step 1, the first exposure head and the second exposure head so that an image is connected between the first specific pixel and the second specific pixel. The present invention relates to an image forming apparatus that corrects image data input to the.
[0048]
In the image forming apparatus, an actual position of the first specific pixel and the second specific pixel is specified by the pixel position specifying method according to claim 1, and the first exposure head and the second position are determined based on the position. The first specific pixel and the second specific pixel are connected by correcting image data input to the exposure head.
[0049]
Therefore, even if the position of the exposure head is shifted for some reason, the image shift or overlap between the exposure heads is automatically corrected, so that the image shift or overlap does not occur.
[0050]
The invention described in claim 8 includes means for selectively turning on / off a plurality of pixels, and also includes a plurality of exposure heads that form an image by exposing while scanning the image forming surface in a certain direction. In addition, exposure means in which the pixels of the exposure head are arranged obliquely with respect to the scanning direction, and beam position detection means for detecting the position of the exposure beam of each exposure head, the pixel array of the exposure head And at least one is disposed along the Y-axis parallel to the scanning direction of the exposure apparatus and the other is disposed along the X-axis direction orthogonal to the Y-axis direction. A beam position detecting means having a pair of slit portions and a light amount measuring means for measuring the light amount of the exposure beam transmitted through the slit portion, and based on the exposure beam position detected by the beam position detecting means; A pixel position specifying unit that specifies a position of a pixel of the exposure head; and an exposure control unit that controls the exposure head based on the pixel position specified by the pixel position specifying unit. Sequentially turn on the pixels near the joint of the image in the first exposure head, the pixel position when the light amount of the exposure beam passing through one of the slits in the beam position detection means reaches a peak, The position of the first specific pixel is determined from the pixel position when the light amount of the exposure beam passing through the other of the slit portions reaches the peak in the beam position detection means, and the difference between the Y coordinates of the two pixels, Next, when the pixels of the second exposure head are sequentially turned on and the light amount of the exposure beam passing through one of the slit portions reaches the peak in the beam position detecting means From the pixel position, the pixel position when the light amount of the exposure beam passing through the other of the slit portions in the beam position detection means reaches a peak, and the difference between the Y coordinates of the two pixels, the second specific pixel The position is specified, and the exposure control unit is configured to generate an image between the first specific pixel and the second specific pixel based on the positions of the first specific pixel and the second specific pixel specified by the pixel position specifying unit. The present invention relates to an image forming apparatus that corrects image data input to the first exposure head and the second exposure head so as to be connected.
[0051]
In the image forming apparatus, the actual positions of the first specific pixel and the second specific pixel are specified by the pixel position specifying method according to claim 2.
[0052]
Therefore, in addition to the features of the image forming apparatus according to claim 6, the image forming apparatus does not need to move the beam position detecting unit while specifying the positions of the first specific pixel and the second specific pixel. Therefore, the pixel position specifying operation can be further simplified.
[0053]
The invention according to claim 9 includes means for selectively turning on / off a plurality of pixels, and a plurality of exposure heads for forming an image by exposing the image forming surface while scanning in a certain direction. An exposure means, a first slit portion that is long in the Y-axis direction, a second slit portion that is long in the X-axis direction, and the first and second portions are formed to be movable along the Y-axis direction and the X-axis direction on the reference plane. A beam position detecting unit having a light amount measuring unit for measuring the amount of light of the exposure beam that passes through the slit portion, and the position of the pixel of the exposure head is specified based on the exposure beam position detected by the beam position detecting unit Pixel position specifying means, and exposure control means for controlling the exposure head based on the pixel position specified by the pixel position specifying means, wherein the pixel position specifying means comprises the exposure means In the first exposure head, the first specific pixel near the joint of the image is turned on, the beam position detecting means is moved along the X-axis direction and the Y-axis direction, and the first slit portion and the second slit The position of the first specific pixel is specified based on the position of the beam position detection means when the amount of the exposure beam transmitted through the slit reaches a peak, and then the image of the image at the second exposure head is determined by the exposure means. The second specific pixel in the vicinity of the joint is turned on, the beam position detecting means is moved along the X-axis direction and the Y-axis direction, and the amount of the exposure beam transmitted through the first slit portion and the second slit portion is changed. The position of the second specific pixel is specified based on the position of the beam position detecting means when the peak is reached, and the exposure control means is configured to specify the first specified by the beam position detecting means. Based on the position of the specific pixel and the second specific pixel, image data input to the first exposure head and the second exposure head so that an image is connected between the first specific pixel and the second specific pixel. The present invention relates to an image forming apparatus characterized by correcting.
[0054]
In the image forming apparatus, the actual positions of the first specific pixel and the second specific pixel are specified by the pixel position specifying method according to claim 3.
[0055]
Therefore, in addition to the features of the image forming apparatus according to claim 6, the image forming apparatus has a case where the first specific pixel and the second specific pixel are separated not only in the Y axis direction but also in the X axis direction. Also, the actual positions of the first specific pixel and the second specific pixel are specified, and the exposure of the first exposure head and the second exposure head is controlled based on this position, thereby eliminating image shift and overlap. It has the feature that it can.
[0056]
According to a tenth aspect of the present invention, the means for selectively turning on / off a plurality of pixels in the exposure head modulates light from a light source according to input image data to form an image. The present invention relates to an image forming apparatus as an element.
[0057]
The image forming apparatus according to any one of claims 6 to 8, wherein a spatial modulation element is used as means for selectively turning on / off a plurality of pixels in the exposure head.
[0058]
According to an eleventh aspect of the present invention, the spatial modulation element includes a large number of micro-reflecting mirrors that reflect light from a light source and can take one of two positions. The present invention relates to an image forming apparatus that is a DMD that forms pixels by switching to one of the two positions according to data and switching a reflection path of light from the light source.
[0059]
The image forming apparatus is an example in which a DMD is used as a spatial light modulation element in the image forming apparatus according to claim 10.
[0060]
DETAILED DESCRIPTION OF THE INVENTION
1. Embodiment 1
An example of the exposure apparatus of the present invention will be described below.
[0061]
The exposure apparatus according to the first embodiment is a so-called flood bed type, and includes a flat exposure stage 152 that holds and holds a sheet-like photosensitive material 150 on the surface, as shown in FIG.
[0062]
The exposure apparatus includes a thick plate-like installation table 156 supported by four legs 154, and two guides provided on the upper surface of the installation table 156 along the stage moving direction indicated by arrows in FIG. 158. The exposure stage 152 is arranged such 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 stage 152 moves along the guide 158 by a driving device (not shown).
[0063]
A U-shaped gate 160 is provided at the center of the installation table 156 so as to straddle the movement path of the exposure stage 152. Each end 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) 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 movement path of the exposure stage 152. The scanner 162 and the detection sensor 164 are connected to a controller (not shown) that controls them, and are controlled to be exposed at a predetermined timing when exposure is performed by the exposure head 166, as will be described later.
[0064]
At the edge of the upstream side (hereinafter, simply referred to as “upstream side”) along the transport direction (scanning direction) in the exposure stage 152, a “<” shape that opens in the X-axis direction is formed. A plurality of formed slits 120 are formed.
[0065]
The slit 120 includes a slit 120a positioned on the upstream side and a slit 120b positioned on the downstream side. The slit 120a and the slit 120b are orthogonal to each other, and the slit 120a has an angle of 135 degrees and the slit 120b has an angle of 45 degrees with respect to the Y axis.
[0066]
A detector (not shown) that detects light from the exposure head 166 is formed below the slit 120.
[0067]
The slit 120 and the detector move along the Y-axis direction together with the exposure stage 152.
[0068]
The slit 120 and the detector correspond to beam position detecting means in the present invention.
[0069]
In the first embodiment, the slit 120a and the slit 120b are formed so as to form an angle of 45 degrees with respect to the scanning direction. However, the slit 120a and the slit 120b are formed with respect to the pixel array of the exposure head 166. The angle with respect to the scanning direction is not limited to the angle as long as it is inclined with respect to the scanning direction, that is, the stage moving direction. Further, a diffraction grating may be used instead of the slit 120.
[0070]
As shown in FIGS. 2 and 3B, the scanner 162 includes a plurality of exposure heads 166 arranged in a substantially matrix of m rows and n columns (for example, 2 rows and 5 columns).
[0071]
As shown in FIG. 2, the image area P, which is an area exposed by the exposure head 166, has a rectangular shape with short sides along the scanning direction, and is inclined at a predetermined inclination angle θ with respect to the scanning direction. . As the exposure stage 152 moves, a strip-shaped exposed area 170 is formed on the photosensitive material 150 for each exposure head 166. As shown in FIGS. 1 and 2, the scanning direction is opposite to the stage moving direction.
[0072]
Also, as shown in FIGS. 3A and 3B, the exposure of each row arranged in a line so that each of the strip-shaped exposed areas 170 partially overlaps the adjacent exposed areas 170 is performed. Each of the heads is arranged so as to be shifted in the arrangement direction by a predetermined interval (a natural number multiple of the long side of the image region, 1 in this embodiment). Therefore, for example, the unexposed portion between the image region 168A located on the leftmost side of the first row and the image region 168C located on the right side of the image region 168A is the image located on the leftmost side of the second row. The area 168B is exposed. Similarly, a portion that cannot be exposed between the image area 168B and the image area 168D located on the right side of the image area 168B is exposed by the image area 168C.
[0073]
Each of the exposure heads 166A to 166J is a spatial light modulation element that modulates an incident light beam for each pixel in accordance with image data, as shown in FIGS. 4 and 5A and 5B. And a digital micromirror device (DMD) 50. The DMD 50 is connected to a controller (not shown) that includes a data processing unit and a mirror drive control unit. The data processing unit of the 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.
[0074]
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.
[0075]
On the light incident side of the DMD 50, a fiber array light source 66 including a laser emitting section in which emission ends (light emitting points) of optical fibers are arranged in a line along a direction corresponding to the long side direction of the image region P, a fiber A lens system 67 for correcting the laser light emitted from the array light source 66 and condensing it on the DMD, and a reflecting mirror 69 for reflecting the laser light transmitted through the lens system 67 toward the DMD 50 are arranged in this order.
[0076]
The lens system 67 includes a pair of combination lenses 71 that collimate the laser light emitted from the fiber array light source 66 and a pair of combination lenses that correct the light quantity distribution of the collimated laser light to be uniform. 73 and a condensing lens 75 that condenses the laser light whose light quantity distribution is corrected on the DMD. With respect to the arrangement direction of the laser emitting ends, the combination lens 73 spreads the light beam at a portion close to the optical axis of the lens and contracts the light beam at a portion away from the optical axis, and with respect to a direction orthogonal to the arrangement direction. Has a function of allowing light to pass through as it is, and corrects the laser light so that the light quantity distribution is uniform.
[0077]
Further, on the light reflection side of the DMD 50, lens systems 54 and 58 for forming an image of the laser light reflected by the DMD 50 on the scanning surface (exposed surface) 56 of the photosensitive material 150 are arranged. The lens systems 54 and 58 are arranged so that the DMD 50 and the exposed surface 56 are in a conjugate relationship.
[0078]
In the present embodiment, the laser light emitted from the fiber array light source 66 is made uniform and incident on the DMD 50, and then each pixel is enlarged and condensed by these lens systems 54 and 58 by about 5 times. Is set to
[0079]
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, it is a mirror device configured by arranging micromirrors with a pitch of 13.68 μm, 1024 × 768) in a grid 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. A silicon gate CMOS SRAM cell 60 manufactured in a normal semiconductor memory manufacturing line is disposed directly below the micromirror 62 via a support including a hinge and a yoke, and is entirely monolithic (integrated type). ).
[0080]
When a digital signal indicating the tilt state (modulation state) of the micromirror 60 is written in the SRAM cell 60 of the DMD 50 and further the digital signal is output from the SRAM cell 60 to the micromirror 62, the micromirror 62 supported by the support column. However, it is tilted in 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. 7A shows a state where the micromirror 62 is tilted to + α degrees when the micromirror 62 is in an on state, and FIG. 7B shows a state where the micromirror 62 is tilted to −α degrees when the micromirror 62 is in an 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. .
[0081]
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. A light absorber (not shown) is arranged in the direction in which the light beam is reflected by the micromirror 62 in the off state.
[0082]
As described above, in the scanner 162, the portion that cannot be exposed between the image region 168A located on the leftmost side of the first row and the image region 168C located on the right side of the image region 168A is the most in the second row. Since the image area 168B located on the left side is exposed, the image area connected to the image area 168A is the image area 168B. FIG. 8 shows the positional relationship between the image area 168A and the image area 168B. In FIG. 8 and subsequent figures, the scanning direction is taken as the X axis and the arrangement direction of the exposure heads 166 is taken as the Y axis.
[0083]
As shown in FIG. 8, the image region 168A and the image region 168B are connected by a connection pixel P1 that is a pixel of the exposure head 166A and a connection pixel P2 that is a pixel of the exposure head 166B. The connection pixel P1 and the connection pixel P2 are examples of the first specific pixel and the second specific pixel in the present invention, respectively.
[0084]
Hereinafter, a procedure for selecting the connection pixel P1 and the connection pixel P2 and specifying the actual position will be described.
[0085]
First, the exposure stage 152 is moved so that the slit 120 is positioned below the scanner 162. Among the pixels of the exposure head 166A, the pixel to be overlapped with the pixel of the exposure head 166B is selected as the connecting pixel P1 and lit.
[0086]
Then, as shown in FIGS. 9 and 10, the exposure stage 152 is slowly moved to move the slit 120 along the Y-axis direction and is positioned in the image region 168A. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y0). Here, as described above, the slit 120a forms an angle of 135 degrees with respect to the Y axis, and the slit 120b forms an angle of 45 degrees with respect to the Y axis. In FIG. 10 and subsequent figures, the direction rotating in the counterclockwise direction from the Y axis is defined as a positive angle.
[0087]
Next, as shown in FIG. 10, the exposure stage 152 is moved, and the slit 120 is moved to the right in FIG. 10 along the Y axis. Then, as shown by a two-dot chain line in FIG. 10, the exposure stage 152 is stopped when the light from the connecting pixel P1 passes through the left slit 120a and is detected by the detector. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y11).
[0088]
Next, the exposure stage 152 is moved, and the slit 120 is moved to the left in FIG. 11 along the Y axis. Then, as shown by a two-dot chain line in FIG. 11, the exposure stage 152 is stopped when the light from the connecting pixel p2 passes through the right slit 120b and is detected by the detector. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y12).
[0089]
Here, if the coordinates of the connecting pixel P1 are (X1, Y1), X1 = X0 + (Y11−Y12) / 2 and Y1 = (Y11 + Y12) / 2.
[0090]
When the coordinates of the connection pixel P1 are obtained, the connection pixel P1 is erased, and among the pixels of the exposure head 166B, the pixel that should be connected to the image region 168A and close to the connection pixel P1 is selected as the connection pixel p2. Lights up.
[0091]
Then, the exposure stage 152 is moved by Y to position the slit 120 in the image area 168B. At this time, the coordinates of the intersection of the slit 120a and the slit 120b are (X0, Y0 + Y).
[0092]
Then, as shown in FIG. 11, the exposure stage 152 is moved, and the slit 120 is moved rightward in FIG. 11 along the Y axis. As shown by a two-dot chain line in FIG. 11, the exposure stage 152 is stopped when the light from the connecting pixel p2 passes through the left slit 120a and is detected by the detector. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y21).
[0093]
Next, the exposure stage 152 is moved, and the slit 120 is moved to the left in FIG. 11 along the Y axis. Then, as shown by a two-dot chain line in FIG. 11, the exposure stage 152 is stopped when the light from the connecting pixel P1 passes through the right slit 120b and is detected by the detector. Let the intersection of the slit 120a and the slit 120b at this time be (X0, Y22).
[0094]
Here, if the coordinates of the connection pixel p2 are (x2, y2), x2 = X0 + (Y21−Y22) / 2 and y2 = (Y21 + Y22) / 2.
[0095]
As shown in FIG. 12, for the connection pixel p2 (x2, y2) obtained in this way, an X coordinate difference ΔX = x2−X1 with the connection pixel P1 is obtained. Then, among the pixels p2, the pixel having the smallest X coordinate difference ΔX is selected as the connecting pixel P2 (X2, Y2).
[0096]
Since the shift in the X direction between the connecting pixel P1 and the connecting pixel P2 is extremely small, the exposure timing is corrected to remove the shift in the Y-axis direction, and the exposure head 166A and the exposure head 166B so that the images overlap in the X direction. By controlling the image data input to, it is possible to remove image shift and overlap between the connecting pixel P1 and the connecting pixel P2 as shown in FIG.
[0097]
Note that a plurality of connecting pixels P1 are specified in the exposure head 166A, the actual XY coordinates (X1, Y1) are specified for each of the plurality of connecting pixels P1 according to the procedure, and the exposure head 166B is specified for each of the connecting pixels P1. By specifying the connecting pixel P2 from these pixels and specifying the actual XY coordinates (X2, Y2), it is possible to further reduce the shift and overlap of the image between the exposure head 166A and the exposure head 166B.
[0098]
In the exposure apparatus according to the first embodiment, the exposure stage is moved and the amount of the exposure beam transmitted through the slit 120a and the slit 120b is detected by the detector, thereby connecting the pixels of the exposure head 166A and the exposure head 166B to the pixel P1 and While selecting the connection pixel P2, the actual position can be specified.
[0099]
Therefore, an expensive and large-sized additional facility is not required to select the connecting pixel P1 and the connecting pixel P2 and specify the position.
[0100]
Furthermore, even when the relative positional relationship between the exposure head 166A and the exposure head 166B deviates for some reason, the exposure head 166A and the exposure head 166A are exposed based on the positional information regarding the actual positions of the connection pixel P1 and the connection pixel P2. By controlling the image data input to the head 166B, it is possible to accurately correct the deviation or overlap between the image between the exposure head 166A and the exposure head 166B.
[0101]
In the above, the method of specifying the connecting pixels of the exposure head 166A and the exposure head 166B by using the slit 120a and the slit 120b and forming an image without rubbing or overlapping has been described. However, by repeating the same procedure sequentially, the exposure is performed. The connection pixels between all the exposure heads 166 of the apparatus 100 are specified, and image data shift, image rotation, magnification conversion, etc. are performed on the image data input to the exposure head 166 so that the images overlap at the connection pixels. Correction can be performed, and an image with little shift at the joint can be formed over the entire exposure region.
[0102]
2. Embodiment 2
FIG. 14 shows the arrangement of an exposure apparatus according to the second embodiment.
[0103]
As shown in FIG. 14, the upstream edge of the exposure stage 152 of the exposure apparatus according to the second embodiment includes a slit 130a parallel to the Y axis and a slit 130b parallel to the X axis. A slit 130 is provided. The slits 130a and 130b are provided so as to intersect with a T-shape. Below the slits 130a and 130b, a detector for detecting an exposure beam transmitted through the slits 130a and 130b is provided.
[0104]
The exposure apparatus according to the second embodiment has the same configuration as the exposure apparatus of the first embodiment except for the above points.
[0105]
In the exposure apparatus according to the second embodiment, a procedure for specifying the position by selecting the connecting pixel P1 from the pixels of the exposure head 166A will be described.
[0106]
First, the exposure stage 152 is moved so that the slit 130 is positioned near the joint between the image area 168A and the image area 168B.
[0107]
When the slit 130 is positioned below the exposure head 166A and the exposure head 166B, the exposure stage 152 is stopped at the position. Then, as shown in FIG. 15, the pixels are sequentially lit along a certain row direction (lateral direction) of the exposure head 166A. Similarly, the pixels are sequentially lighted from below to above along a certain column direction (vertical direction) of the exposure head 166A.
[0108]
As shown in FIG. 15, when the pixel P1 (a, n) is turned on, the detector of the slit 130a detects the peak of the light amount, and the pixel P ^* When the detector of the slit 130b detects the peak of the light amount when 1 (m, b) is turned on, the pixel P1 of the exposure head 166A is selected as the connecting pixel P1, and the pixel P ^* 1 is selected as an auxiliary pixel. The connecting pixel P1 (a, n) and the auxiliary pixel P ^* (A, n) and (m, b) of 1 (m, b) are connected pixels P1 and auxiliary pixels P, respectively. ^* 1 shows the X and Y coordinates.
[0109]
Here, as shown in FIG. 16, the connecting pixel P1 (a, n) and the auxiliary pixel P ^* A position difference ΔY1 in the Y-axis direction from 1 (m, b) is expressed by the following equation:
ΔY1 = b−n
Given in.
[0110]
Next, the exposure stage 152 is moved by the distance Ys, and the pixels in a certain row of the exposure head 166B are sequentially lit from the left to the right. Similarly, the pixels in a certain column are viewed from below along the X-axis direction. Light up sequentially upward.
[0111]
At this time, when the pixel P2 (c, n ′) is turned on, the detector of the slit 130a detects the peak of the light amount, and the pixel P ^* If the detector of the slit 130b detects the peak of the light amount when 2 (m ′, d) is turned on, the pixel P2 (c, n ′) is selected as a connecting pixel, and the pixel pixel P ^* 2 is selected as an auxiliary pixel.
[0112]
The connecting pixel P2 (c, n ′) and the auxiliary pixel P ^* The position difference ΔY2 in the Y-axis direction from 2 (m ′, b) is expressed by the following formula:
ΔY2 = (d−n ′)
Given in.
[0113]
Since the slit 130 does not move at all in the X-axis direction when the connection pixel P1 (a, n) is detected and when the connection pixel P2 (c, n ′) is detected, the connection pixel P1 ( a, n) and the connecting pixel P2 (c, n ′) have the same X coordinate. On the other hand, the distance in the Y-axis direction is expressed by the following formula:
Ys + ΔY2−ΔY1
= Ys + dn− (b−n)
Given in.
[0114]
Therefore, by performing the lighting timing correction according to the distance in the Y-axis direction between the connection pixel P1 (a, n) and the connection pixel P2 (c, n ′), the exposure head 166A and the exposure head 166B. Can be eliminated.
[0115]
The example in which the connecting pixel P1 (a, n) and the connecting pixel P2 (c, n ′) are selected and specified by using the slit 130a and the slit 130b one by one has been described. Thus, if a plurality of slits 130a and 130b are provided in accordance with the pitch along the X direction and Y direction of the pixels of the exposure head 166A and the exposure head 166B, the amount of transmitted light is increased, so that the pixel detection accuracy is improved. This makes it possible to connect images with higher accuracy.
[0116]
In the exposure apparatus according to the second embodiment, since the joint pixel P2 has the same X coordinate as the joint pixel P1, the same image data in the X direction is input to the exposure head 166A and the exposure head 166B. If the image data input is controlled, the image shift between the exposure head 166A and the exposure head 166B can be completely removed. Further, the image shift in the Y-axis direction can also be removed by adjusting the lighting timing between the connection pixel P1 and the connection pixel P2.
[0117]
Therefore, it is possible to connect images with higher accuracy than the exposure apparatus according to the first embodiment.
[0118]
In addition, since the exposure stage 152 is stopped while the connection pixel P1 and the connection pixel P2 are selected, the exposure table 152 is selected at the time of selecting and specifying a connection image, as compared with the exposure apparatus according to the first embodiment. The frequency of moving can be further reduced.
[0119]
In the above, the method of specifying the connecting pixels of the exposure head 166A and the exposure head 166B by using the slit 130a and the slit 130b and forming an image without rubbing or overlapping has been described. The connection pixels between all the exposure heads 166 of the apparatus are specified, and correction such as image data shift, image rotation, and magnification conversion is performed on the image data input to the exposure head 166 so that the images overlap at the connection pixels. And an image with little shift at the joint can be formed over the entire exposure region.
[0120]
3. Embodiment 3
FIG. 18 shows the arrangement of an exposure apparatus according to the third embodiment.
[0121]
As shown in FIG. 18, in the exposure apparatus according to the third embodiment, a beam position detection device 140 corresponding to the beam position detection means of the present invention is provided at the upstream edge of the exposure stage 152.
[0122]
Details of the beam position detector 140 are shown in FIG.
[0123]
As shown in FIGS. 18 and 19, the beam position detection device 140 includes a base 142 that slides in the groove 148 provided along the X-axis direction at the upstream edge of the exposure stage 152, and A linear encoder 144 that detects the position of the base 142 in the X-axis direction is provided along the moving direction of the base 142, and the base 142 is moved inside the groove 148. And a pair of ball screws 146. The base 142 is provided with two linear guides (not shown) in parallel with each other. The ball screw 146 is rotated by a motor (not shown) to move the base 142.
[0124]
The base 142 is formed so that the upper surface is located on the same plane as the exposure surface of the exposure stage 152. On the upper surface of the base 142, a slit 140a is provided along the X-axis direction, and a slit 140b is provided along the Y-axis direction. The slit 140a and the slit 140b are orthogonal to each other. Below the slits 140a and 140b, a detector (not shown) for detecting the light of the exposure beam that has passed through the slits 140a and 140b is provided.
[0125]
Hereinafter, in the exposure apparatus, the specific pixel P1 and the specific pixel P2 are selected from the pixels of the exposure head 166A and the exposure head 166B, and their actual positions are specified.
[0126]
First, the exposure head 152 is moved to move the beam position detection device 140 along the Y-axis direction, the base 142 of the beam position detection device 140 is moved along the groove 148, and the base 142 is moved to the image region 168A. And the image area 168B.
[0127]
Next, among the pixels of the exposure head 166A, the pixel to be connected to the image region 168B is selected and set as a connection pixel P1.
[0128]
Then, as shown in FIG. 20, the exposure head 152 is finely moved, and the base 142 is moved along the Y-axis direction. When the amount of light transmitted through the slit 140a from the connection pixel P1 reaches the peak, the exposure head 152 is stopped, and the position of the exposure stage in the Y-axis direction is detected by a linear encoder (not shown) provided on the exposure stage 152. Is detected. The position in the Y-axis direction is connected as the Y coordinate Y1 of the pixel P1.
[0129]
Next, the base 142 is moved in the X-axis direction by the ball screw 146. When the amount of light transmitted through the slit 140b reaches the peak, the linear encoder 144 moves the position of the base 142 in the X-axis direction at this time. To detect. The position in the X-axis direction is connected as the X coordinate X1 of the pixel P1.
[0130]
When the position of the connection pixel P1 is specified, the connection pixel P1 is turned off, and instead of the pixels of the exposure head 166B, the pixel p2 to be connected to the image region 168A is turned on, and the beam position detection device 140 performs the same procedure. To obtain the XY coordinates (x2, y2) of the pixel p2.
[0131]
The XY coordinates (x2, y2) of the pixel p2 thus obtained are compared with the XY coordinates (X1, Y1) of the connection pixel P1, and the pixel p2 closest to the connection pixel P1 is compared with the connection pixel P2 (X2, X2). Y2) is selected.
[0132]
When the actual positions of the connection pixel P1 and the connection pixel P2 are specified in this way, the image data input to the exposure head 166A and the exposure head 166B is controlled based on the position, and the connection pixel P1 and the connection pixel P2 are controlled. So that the images are connected.
[0133]
In the exposure apparatus according to the third embodiment, since the accurate XY coordinates of the connection pixel P1 and the connection pixel P2 can be obtained in a short time by the beam position detection device 140, the X coordinate is not necessarily the same as the connection pixel P1 and the connection pixel P2. Even when a non-selected one is selected, it is possible to connect the images accurately.
[0134]
In the above, the method of specifying the connecting pixels of the exposure head 166A and the exposure head 166B by using the beam position detection device 140 and forming an image without rubbing or overlapping has been described. However, by repeating the same procedure sequentially, the exposure is performed. The connection pixels between all the exposure heads 166 of the apparatus 100 are specified, and image data shift, image rotation, magnification conversion, etc. are performed on the image data input to the exposure head 166 so that the images overlap at the connection pixels. Correction can be performed, and an image with little shift at the joint can be formed over the entire exposure region.
[0135]
【The invention's effect】
As described above, according to the present invention, in the multi-head exposure apparatus, there is provided an exposure apparatus with extremely small deviation between images formed by each exposure head, and an image deviation correction method that can be performed by the exposure apparatus. Is done.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the arrangement of an exposure apparatus according to Embodiment 1. FIG.
FIG. 2 is a perspective view showing a configuration of a scanner provided in the exposure apparatus according to the first embodiment.
FIG. 3 is a plan view showing exposed areas formed on a photosensitive material, and a schematic view showing an arrangement of image areas by each exposure head.
FIG. 4 is a perspective view showing a schematic configuration of an exposure head provided in the exposure apparatus according to the first embodiment.
5 is a cross-sectional view in the scanning direction along the optical axis showing the configuration of the exposure head shown in FIG. 4. FIG.
6 is a partially enlarged view showing a configuration of a digital micromirror device (DMD) provided in the exposure head shown in FIG. 4. FIG.
FIG. 7 is an explanatory diagram showing an operation of the DMD shown in FIG. 6;
FIG. 8 is a diagram illustrating an exposure apparatus according to the first embodiment in which an image area irradiated by one exposure head and an image area irradiated by another exposure head are connected to the one image area; It is a top view which shows the positional relationship with the other image area | region to do.
FIG. 9 is a plan view showing a positional relationship between the one image region and the other image region and a slit provided in an exposure stage of the exposure apparatus.
FIG. 10 is an explanatory diagram showing a procedure for specifying the position of one connection pixel, which is a connection pixel of the one exposure head, by the slit.
FIG. 11 is an explanatory diagram showing a procedure for specifying, by the slit, the position of a pixel to be connected to the one image area among the pixels of the other exposure head.
FIG. 12 is an explanatory diagram showing a procedure for selecting another connection pixel from the pixels of the other exposure head whose position is specified by the procedure of FIG. 11;
FIG. 13 is a plan view showing a state where the one image region and another image region are connected by the one connection pixel and the other connection pixel.
FIG. 14 is a perspective view showing the arrangement of an exposure apparatus according to the second embodiment.
FIG. 15 is an explanatory diagram showing a procedure for specifying the position of one connected pixel in one exposure head by a slit provided in the exposure stage in the exposure apparatus according to the second embodiment.
FIG. 16 shows a connecting pixel P1 and an auxiliary pixel P. ^* 2 is an explanatory diagram showing a difference in position along the Y-axis direction with respect to 1. FIG.
FIG. 17 is an explanatory diagram showing a procedure for specifying a position of a connected pixel using a plurality of slits parallel to each other in the exposure apparatus according to the second embodiment.
FIG. 18 is a perspective view showing the arrangement of an exposure apparatus according to the third embodiment.
FIG. 19 is an enlarged view showing details of a configuration of a beam detection apparatus provided in the exposure apparatus according to the third embodiment.
FIG. 20 is an explanatory diagram showing a procedure for specifying XY coordinates of connected pixels by a beam position detection device in the exposure apparatus according to the third embodiment.
[Explanation of symbols]
50 DMD
53 Reflected light image (exposure beam)
54, 58 Lens system
56 Scanning surface (exposed surface)
64 laser module
66 Fiber array light source
68 Laser emitting part
73 Combination lens
120 slits
130 slit
140 Beam position detector
140a slit
140b slit
150 Photosensitive material
152 stage (moving means)
162 Scanner
166 Exposure head
170 Exposed area

Claims (12)

A first image formed by an exposure beam of a first exposure head in an image forming apparatus that forms an image by scanning a plurality of exposure heads having means for selectively turning on / off a plurality of pixels in a certain direction The pixel position of the joint between the region and the second image region formed by the exposure beam of the second exposure head and connected to the first image region is defined as the first exposure head and the second exposure head. A pixel position specifying method for measuring and specifying the position of the exposure beam of
It is formed so as to be relatively movable on a reference plane along the Y-axis direction parallel to the scanning direction of the exposure apparatus, is relatively inclined with respect to the pixel array of the exposure head, and is the same A pair of slit portions that are overlapped in the scanning direction so that pixels can be detected and are arranged so as to intersect with each other; and a light amount measuring unit that measures the light amount of the exposure beam that passes through the slit portions; And a beam position detection means having
Of the pixels formed by the exposure beam of the first exposure head, the first specific pixel located on the joint is turned on to move the beam position detecting means along the Y-axis direction, and the slit portion The position of the first specific pixel is specified based on the position of the intersection of the slit portions in the beam position detection means and the angle formed by the slit portions when the light amount of the exposure beam passing through one and the other reaches a peak A first pixel position specifying step,
Of the pixels formed by the exposure beam of the second exposure head, the second specific pixel located on the joint is turned on to move the beam position detecting means along the Y-axis direction, and the slit portion The second specific pixel position is specified based on the position of the intersection of the slit portions and the angle formed by the slit portions in the beam position detection means when the light amount of the exposure beam passing through one and the other reaches the peak. A pixel position specifying method, comprising: a two-pixel position specifying step. A first image formed by an exposure beam of a first exposure head in an image forming apparatus that forms an image by scanning a plurality of exposure heads having means for selectively turning on / off a plurality of pixels in a certain direction The pixel position of the joint between the region and the second image region formed by the exposure beam of the second exposure head and connected to the first image region is defined as the first exposure head and the second exposure head. A pixel position specifying method for measuring and specifying the position of the exposure beam of
The exposure apparatus is formed so as to be relatively movable on a reference plane along a Y-axis direction parallel to the scanning direction of the exposure apparatus, and is relatively oblique to the pixel array of the exposure head. At least one pair of slit portions, one of which is disposed along the Y axis parallel to the scanning direction of the exposure apparatus and the other of which is disposed along the X axis direction perpendicular to the Y axis direction; A light amount measuring means for measuring the light amount of the exposure beam that passes through the slit portion, and a beam position detecting means is used for measuring the position of the exposure beam,
Among the pixels formed by the exposure beam of the first exposure head, sequentially turn on the pixels in the column along the Y-axis direction including the first specific pixel located on the joint and the column adjacent to the column, A pixel that is turned on when the light amount of the exposure beam that passes through the slit portion in the Y-axis direction reaches a peak in the beam position detecting means is a first specific pixel, and the slit portion in the X-axis direction is in the beam position detecting means. A first pixel position specifying step in which a pixel lit when the amount of light of the passing exposure beam reaches a peak is a first auxiliary pixel ;
The beam position detecting means is moved by a predetermined distance Ys in the Y-axis direction, and among the pixels formed by the exposure beam of the second exposure head, the Y-axis direction including the second specific pixel located on the joint Are sequentially turned on, and a pixel that is lit when the light amount of the exposure beam passing through the slit portion in the Y-axis direction reaches a peak in the beam position detecting means A second pixel position identifying step in which the second auxiliary pixel is a pixel that is turned on when the light amount of the exposure beam that passes through the slit portion in the X-axis direction reaches a peak in the beam position detecting unit .
A pixel position specifying method characterized by comprising: A first image formed by an exposure beam of a first exposure head in an image forming apparatus that forms an image by scanning a plurality of exposure heads having means for selectively turning on / off a plurality of pixels in a certain direction The pixel position of the joint between the region and the second image region formed by the exposure beam of the second exposure head and connected to the first image region is defined as the first exposure head and the second exposure head. A pixel position specifying method for measuring and specifying the position of the exposure beam of
A first slit portion that is formed so as to be movable along the Y-axis direction and the X-axis direction on the reference plane, is inclined relatively to the pixel array of the exposure head and extends in the Y-axis direction, and the exposure A second slit portion that is inclined with respect to the pixel array of the head and extends in the X-axis direction, and a light amount measuring unit that measures a light amount of the exposure beam that passes through the first and second slit portions; the beam position detector having, together with the use in the measurement of the position of the exposure beam,
Of the pixels formed by the exposure beam of the first exposure head, the first specific pixel located on the joint is turned on, the beam position detecting means is moved in the X-axis direction and the Y-axis direction, and the first A first pixel position specifying step for specifying the position of the first specific pixel based on the position of the beam position detecting means when the light quantity of the exposure beam passing through the first slit part and the second slit part reaches a peak; ,
Of the pixels formed by the exposure beam of the second exposure head, the second specific pixel located on the joint is turned on, the beam position detecting means is moved in the X-axis direction and the Y-axis direction, and the first A second pixel position specifying step for specifying the position of the second specific pixel based on the position of the beam position detecting means when the light amount of the exposure beam passing through the one slit part and the second slit part reaches a peak; A pixel position specifying method characterized by comprising: In an image forming apparatus that scans a plurality of exposure heads having means for selectively turning on / off a plurality of pixels in a predetermined direction to form an image, image shift correction for correcting image shift and overlap between the exposure heads A method,
A pixel position specifying step for specifying the positions of the first specific pixel in the first exposure head and the second specific pixel in the second exposure head by the pixel position specifying method according to claim 1 or 3 ,
Based on the positions of the first specific pixel and the second specific pixel specified in the pixel position specifying step, the first specific pixel and the second specific pixel are overlapped at least in the Y-axis direction. An image shift correction method comprising: an image data correction step for correcting image data input to the exposure head and the second exposure head. In the image data correction step,
Regarding the image shift in the Y-axis direction between the first specific pixel and the second specific pixel, the distance in the Y-axis direction between the first specific pixel and the second specific pixel and the exposure head While removing by setting the exposure timing of the first exposure head and the second exposure head according to the scanning speed,
Regarding the image shift in the X-axis direction between the first specific pixel and the second specific pixel, the first exposure head and the first exposure head so that image data overlaps the first specific pixel and the second pixel. The image shift correction method according to claim 4, wherein the image data is removed by inputting image data to the second exposure head. In an image forming apparatus that scans a plurality of exposure heads having means for selectively turning on / off a plurality of pixels in a predetermined direction to form an image, image shift correction for correcting image shift and overlap between the exposure heads A method,
The position of the first specific pixel and the first auxiliary pixel in the first exposure head and the position of the second specific pixel and the second auxiliary pixel in the second exposure head by the pixel position specifying method according to claim 2. A pixel position specifying step for determining a position difference ΔY1 in the Y-axis direction between the first specific pixel and the first auxiliary pixel and a position difference Δ2 in the Y-axis direction between the second specific pixel and the auxiliary pixel; ,
The pixel position positional difference in the Y-axis direction between the first specific pixel obtained in particular step and the first auxiliary pixel [Delta] Y1, the second position difference in the Y-axis direction of the predetermined pixel and the second auxiliary pixel ΔY2 And the first specific pixel and the second specific pixel are input to the first exposure head and the second exposure head so that the first specific pixel and the second specific pixel overlap in the Y-axis direction based on the moving distance Ys of the beam position detecting means. An image shift correction method comprising: an image data correction step for correcting image data. For 3 or more exposure heads,
Specifying the position on the reference plane of the connecting pixels in each image head by the pixel position specifying step;
Image data input to each of the exposure heads is corrected based on the position of the connection pixel specified by the pixel position specifying step so that the image is connected by the connection pixel.
The image shift correction method according to any one of claims 4 to 6 . An exposure means comprising a plurality of exposure heads for selectively turning on / off a plurality of pixels and exposing the image forming surface while scanning the image forming surface in a fixed direction;
Beam position detecting means for detecting the position of the exposure beam of each exposure head, which is formed so as to be movable on a reference plane along a Y-axis direction parallel to the scanning direction. The at least one pair of slit portions which are relatively oblique to each other and overlap in the scanning direction so as to be able to detect the same pixel on both sides, and the exposure is transmitted through the slit portions. A beam position detecting means having a light quantity measuring means for measuring the light quantity of the beam;
Based on the exposure beam position detected by the beam position detecting means, a first image area formed by the exposure beam of the first exposure head of the plurality of exposure heads, Pixel position specifying means for specifying a pixel position of a joint formed with an exposure beam of a second exposure head and connected to the second image area connected to the first image area ;
Exposure control means for controlling the exposure head based on the pixel position of the joint specified by the pixel position specifying means,
The pixel position specifying means includes
Turning on the first specific pixel located at or near the joint of the first image area with the second image area in the exposure means, and moving the beam position detection means along the Y-axis direction; The first identification is based on the position of the beam position detection means and the angle formed by the slit portion when the light amount of the exposure beam that passes through one and the other of the slit parts of the beam position detection means reaches a peak. Locate the pixel,
Turning on the second specific pixel located at or near the joint of the second image area with the first image area in the exposure means, and moving the beam position detection means along the Y-axis direction; Specifying the position of the second specific pixel based on the position of the beam position detection means and the angle formed by the slit when the light amount of the exposure beam that passes through one and the other of the slits reaches a peak;
The exposure control unit is configured to overlap the first specific pixel and the second specific pixel at least in the Y-axis direction based on the positions of the first specific pixel and the second specific pixel specified by the beam position detection unit. As described above, the image forming apparatus corrects image data input to the first exposure head and the second exposure head. The apparatus has means for selectively turning on / off a plurality of pixels, and includes a plurality of exposure heads that expose and form an image while scanning the image forming surface in a certain direction, and the pixels of the exposure head include the scanning Exposure means arranged obliquely with respect to the direction;
Beam position detecting means for detecting the position of the exposure beam of each exposure head, the Y axis being relatively oblique to the pixel array of the exposure head and one of which is parallel to the scanning direction of the exposure apparatus And at least one pair of slit portions disposed along the X-axis direction orthogonal to the Y-axis direction, and a light amount measuring means for measuring the light amount of the exposure beam that passes through the slit portions. A beam position detecting means comprising:
Based on the exposure beam position detected by the beam position detecting means, a first image area formed by the exposure beam of the first exposure head of the plurality of exposure heads, Pixel position specifying means for specifying a pixel position of a joint formed with an exposure beam of a second exposure head and connected to the second image area connected to the first image area;
Exposure control means for controlling the exposure head based on the pixel position of the joint specified by the pixel position specifying means,
The pixel position specifying means includes
Among the pixels of the first image area formed by the first exposure head, a column along the Y-axis direction including the first specific pixel that is a pixel to be connected to the second image area, and the column The pixels in adjacent columns are sequentially turned on, and the pixel that is turned on when the light amount of the exposure beam that passes through the slit portion in the Y-axis direction reaches the peak in the beam position detection unit is set as the first specific pixel, and the beam position A pixel that is turned on when the light amount of the exposure beam that passes through the slit portion in the X-axis direction reaches a peak in the detection means is defined as a first auxiliary pixel,
Next, the beam position detecting means is moved by a predetermined distance Ys in the Y-axis direction, and connected to the first image area among the pixels of the second image area formed by the second exposure head. The light in the exposure beam that passes through the slit portion in the Y-axis direction in the beam position detecting means is sequentially turned on in the column along the Y-axis direction including the second specific pixel that is a power pixel and in the column adjacent to the column. The pixel that is lit when the peak reaches the peak is defined as the second specific pixel, and the pixel that is lit when the light amount of the exposure beam passing through the slit portion in the X-axis direction reaches the peak in the beam position detecting means 2 auxiliary pixels,
Said first positional difference in the Y-axis direction of a particular pixel and the first auxiliary pixel [Delta] Y1, and obtains the positional difference ΔY2 in the Y-axis direction and the second specific pixel and the second auxiliary pixel,
The exposure control means is a Y-axis position difference ΔY1 between the first specific pixel and the first auxiliary pixel obtained by the pixel position specifying means, and a Y-axis direction difference between the second specific pixel and the auxiliary pixel. Based on the positional difference Δ2 and the movement distance Ys of the beam position detecting means, the first exposure head and the second exposure head are arranged so that the first specific pixel and the second specific pixel overlap on the Y axis. An image forming apparatus for correcting input image data. An exposure unit having a plurality of exposure heads that selectively turn on / off a plurality of pixels and that exposes the image forming surface while scanning in a certain direction to form an image;
A first slit portion that is long in the Y-axis direction, a second slit portion that is long in the X-axis direction, and the first and second slit portions are formed so as to be movable on the reference plane along the Y-axis direction and the X-axis direction. A beam position detecting unit having a light amount measuring unit for measuring a light amount of the exposure beam that is transmitted;
Based on the exposure beam position detected by the beam position detecting means, a first image area formed by the exposure beam of the first exposure head of the plurality of exposure heads, Pixel position specifying means for specifying a pixel position of a joint formed with an exposure beam of a second exposure head and connected to the second image area connected to the first image area ;
Exposure control means for controlling the exposure head based on the pixel position of the joint specified by the pixel position specifying means,
The pixel position specifying means includes
Of the pixels formed by the exposure beam of the first exposure head, the first specific pixel located on or in the vicinity of the joint is turned on, and the beam position detector is moved along the X-axis direction and the Y-axis direction. Moving, specifying the position of the first specific pixel based on the position of the beam position detecting means when the amount of light of the exposure beam passing through the first slit portion and the second slit portion reaches a peak, and then
Of the pixels formed by the exposure beam of the second exposure head, the second specific pixel located on or in the vicinity of the joint is turned on, and the beam position detecting means is moved along the X-axis direction and the Y-axis direction. Moving, specifying the position of the second specific pixel based on the position of the beam position detecting means when the amount of light of the exposure beam transmitted through the first slit portion and the second slit portion reaches a peak,
The exposure control unit is configured such that the first specific pixel and the second specific pixel overlap at least in the Y-axis direction based on the positions of the first specific pixel and the second specific pixel specified by the beam position detection unit. As described above, the image forming apparatus corrects image data input to the first exposure head and the second exposure head.     The means for selectively turning on / off a plurality of pixels in the exposure head is a spatial light modulation element that forms an image by modulating light from a light source according to input image data. The image forming apparatus according to claim 1. The spatial light modulator is
A large number of micro-reflecting mirrors that reflect light from a light source and can take one of two positions, and switch the position of the reflecting mirror to one of the two positions according to image data. The image forming apparatus according to claim 11, wherein the image forming apparatus is a DMD that forms pixels by switching a reflection path of light from a light source.

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