JP2004157219A - Exposure head and exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure head and an exposure apparatus which can be formed at a low cost even when a lamp light source is used, which can keep a long life of the lamp and which can suppress consumption of electric power. <P>SOLUTION: The exposure head to be moved in a direction crossing to a specified direction with respect to the face 56 for exposure is composed of a plurality of spatial optical modulating elements 50 comprising a large number of pixel parts two-dimensionally arranged and modulating the illuminating light according to the respective controlling signals; a plurality of lamp light sources 66 each disposed to each one of the spatial optical modulating elements 50; an illumination optical system 67 to irradiate the spatial optical modulating elements 50 with the light emitting from the lamp light sources 66; and an imaging optical system 51 to form an image carried by the spatially modulated light by the plurality of spatial optical modulating elements 50 onto the face 56 for exposure. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exposure head, and more particularly to an exposure head that exposes a photosensitive material with light modulated by a spatial light modulator in accordance with image data, and an exposure apparatus equipped with such an 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]
The DMD is a mirror device in which a number of micromirrors that change the angle of the reflecting surface in accordance with a control signal are two-dimensionally arranged on a semiconductor substrate such as silicon. The exposure apparatus using this DMD basically has a light source 1 that emits laser light, a lens system 2 that collimates the laser light emitted from the light source 1, and a substantially focal position of the lens system 2, for example, as shown in FIG. And an exposure head composed of lens systems 4 and 6 for focusing the laser beam reflected by the DMD 3 on the scanning surface (photosensitive material) 5 and forming an image carried by the laser beam, It comprises moving means (not shown) for moving the exposure head relative to the scanning surface 5. FIG. 9 is a developed view for explaining the optical relationship.
[0004]
In this type of exposure apparatus, each of the micromirrors of the DMD 3 is on / off controlled by a control device (not shown) based on a control signal generated in accordance with image data or the like, and the laser beam thus modulated is the scanning surface 5. While irradiating the photosensitive material, the relative movement, that is, the sub-scanning of the laser beam is performed, and an image is exposed on the photosensitive material.
[0005]
Non-Patent Document 1 and Japanese Patent Application No. 2002-149886 by the present applicant show examples of an exposure apparatus having the above-described configuration.
[0006]
[Non-Patent Document 1]
Akihito Ishikawa “Development shortening by maskless exposure and mass production application”, “Electronics packaging technology”, Technical Research Committee, Vol. 18, no. 6, 2002, p. 74-79
[0007]
[Problems to be solved by the invention]
By the way, the number of pixels of the spatial light modulation elements such as the DMD and the liquid crystal shutter array is usually about several hundreds × several hundreds. A plurality of lines are arranged side by side in a direction crossing the direction of movement, and a large exposure width is ensured in this line-up direction (main scanning direction).
[0008]
On the other hand, in the exposure head having the above configuration, it is considered that not only a laser but also a lamp light source such as a halogen lamp is applied as a light source. Conventionally, when a plurality of exposure heads are applied as described above and this lamp light source is used, light emitted from one lamp light source is incident on the fiber bundle, and a plurality of fibers constituting the fiber bundle are formed. It has been considered to connect each of these to a spatial light modulator such as DMD. That is, in this case, light emitted from one lamp light source is branched by a plurality of fibers and irradiated to each of the plurality of spatial light modulation elements.
[0009]
However, in the exposure head having such a configuration, particularly when a large number of spatial light modulation elements are applied, it is necessary to use a very large output light source as one lamp light source, so that the price of the lamp light source is high. Therefore, the problem that the cost of the exposure head is significantly increased and the problem that the lamp life is short are recognized. Moreover, since the coupling efficiency of the light emitted from the lamp light source to the fiber is low, there is a problem that the power consumption is large.
[0010]
On the other hand, a DMD that is normally used is configured by arranging approximately 800 micromirrors in a two-dimensional manner on a substrate in the main scanning direction and approximately 600 in the sub-scanning direction, and corresponds to one pixel. It takes 100 to 200 μs (microseconds) to modulate the light with one micromirror.
[0011]
For this reason, for example, while continuously moving a plurality of exposure heads arranged in the main scanning direction in the sub-scanning direction, modulation is performed at 200 μs per main scanning line, during which the exposure head is moved by 2 μm in the sub-scanning direction. Case, 500mm ² It took about 50 seconds to expose this area. That is, since DMD has a low modulation speed, there is a problem that high-speed exposure is difficult with an exposure head using DMD as a spatial light modulation element.
[0012]
The present invention has been made to solve the above-described problems. An exposure head and an exposure apparatus that can be formed at low cost even when a lamp light source is used, have a long lamp life, and have low power consumption. The purpose is to provide.
[0013]
In addition, the present invention further aims to provide an exposure head and an exposure apparatus that enable high-speed exposure.
[0014]
[Means for Solving the Problems]
An exposure head according to the present invention comprises:
An exposure head that is moved in a direction crossing a predetermined direction with respect to the exposure surface,
A plurality of spatial light modulation elements in which a large number of pixel units that modulate the irradiated light according to control signals are arranged two-dimensionally;
A plurality of lamp light sources provided one by one for each of these spatial light modulation elements;
An irradiation optical system for irradiating the spatial light modulation element with light emitted from the lamp light source;
And an imaging optical system that forms an image carried by the light spatially modulated by the plurality of spatial light modulation elements on the exposure surface.
[0015]
As the spatial light modulator, for example, the DMD described above, or a liquid crystal shutter in which a large number of liquid crystal cells capable of blocking transmitted light according to each control signal are arranged two-dimensionally on a substrate. An array or the like can be used.
[0016]
In addition, the exposure head of the present invention having the above-described configuration includes a control unit that controls each of the plurality of pixel units smaller than the total number of the pixel units based on a control signal generated according to the exposure information. It is desirable.
[0017]
In this case, it is preferable that the pixel unit controlled by the control unit is a pixel unit included in a region where the length in the direction corresponding to the predetermined direction is longer than the length in the direction intersecting the predetermined direction.
[0018]
Further, the exposure head of the present invention having the above configuration corrects the light amount distribution of light emitted from the lamp light source between the lamp light source and the spatial light modulation element so as to be substantially uniform on the spatial light modulation element. It is desirable to have a light quantity distribution correction optical system.
[0019]
On the other hand, an exposure apparatus according to the present invention comprises the exposure head according to the present invention as described above, and a moving means for relatively moving the exposure head in a direction crossing a predetermined direction with respect to the exposure surface. To do.
[0020]
In the present invention, in order to irradiate the spatial light modulator with a larger amount of light, the configuration of the illumination device that performs polarization composition proposed by the present applicant in Japanese Patent Application No. 2001-252497 is applied to the lamp light source. You can also. One of the lighting devices of this Japanese Patent Application No. 2001-252497 is
Two light sources emitting unpolarized light;
A first lens array plate disposed on the optical path for each of the light sources, extending in at least one dimension and generating an array of lines or points in the vicinity of the rear focal plane;
It has a pitch approximately equal to the pitch of the array of lines or points, and is arranged in the vicinity of the rear focal plane of the first lens array plate, and converts the incident light into a P-polarized light beam or S-polarized light beam only. A polarization conversion element that
The polarization conversion element has a pitch that is approximately ½ of the pitch, and the front focal plane thereof is arranged so as to substantially coincide with the rear focal plane of the first lens array plate, and emits a substantially parallel light beam. Two lens array plates;
An optical system comprising a set of the first lens array plate, the polarization conversion element, and the second lens array plate allows the P-polarized light beam and the S-polarized light beam only from the non-polarized light beam from the light sources. A polarizing element that combines and combines two light beams,
It is characterized by having.
[0021]
Another lighting device proposed here is
n is an integer greater than or equal to 3,
n light sources;
N-1 polarizing elements for polarization-multiplexing two lights;
The optical system comprising at least 2n-2 sets of the first lens array plate, the polarization conversion element, and the second lens array plate according to claim 1,
Light from two light sources out of the n light sources is made only P-polarized light or S-polarized light by the optical system, and is combined by the polarizing element.
The light from the n light sources is multiplexed by repeating the polarization multiplexing in the same manner for the light combined with the polarization or the light from another light source.
[0022]
By applying a lamp as the above-mentioned “light source”, a lamp light source used in the exposure head of the present invention can be configured, and such a lamp light source can generate a larger amount of light that has been combined with a spatial light modulator. Can be irradiated.
[0023]
Since it is as described above, in the present invention, “one lamp light source provided for each of the spatial light modulation elements” may be composed of a plurality of lamps as described above. To do.
[0024]
The exposure head of the present invention can also be incorporated into an illumination optical system proposed by the present applicant in Japanese Patent Application No. 2001-251269. This illumination optical system is an illumination optical system having a spatial light modulation element that improves the amount of incident light and clearly separates on-light and off-light to prevent a reduction in image contrast, of which One is
An illumination light source and incident light from the illumination light source are reflected to form exit light, and the deflection direction of the principal ray of the exit light is freely set to at least two directions of the first deflection direction and the second deflection direction. An illumination optical system having a spatial light modulation element in which a plurality of switching elements are arranged,
The angle between the incident direction of the principal ray of the incident light and the first deflection direction is set to be substantially equal to the angle between the first deflection direction and the second deflection direction. It is characterized by this.
[0025]
Another illumination optical system proposed here is
An illumination light source and incident light from the illumination light source are reflected to form exit light, and the deflection direction of the principal ray of the exit light is freely set to at least two directions of the first deflection direction and the second deflection direction. An illumination optical system having a spatial light modulation element in which a plurality of switching elements are arranged,
The direction of polarization of the principal ray of the emitted light is inclined with respect to the normal direction of the element arrangement surface of the spatial light modulator.
[0026]
The lamp light source and the spatial light modulation element in the exposure head of the present invention can be applied as the “illumination light source” and “spatial light modulation element” described above, respectively. The purpose of can be achieved.
[0027]
Furthermore, the exposure head of the present invention has a configuration of an illumination optical system that performs polarization composition proposed by the present applicant in Japanese Patent Application No. 2000-377022 for a lamp light source in order to irradiate a spatial light modulator with a larger amount of light. Can also be applied. The first of the illumination optical systems is
Two light sources emitting unpolarized light;
A polarization conversion element that converts light from each of the light sources into P-polarized light and S-polarized light, respectively;
A polarizing element for polarizing and combining the converted P-polarized light and S-polarized light;
It is characterized by comprising.
[0028]
The second illumination optical system proposed here is
Three or more light sources emitting unpolarized light;
A polarization conversion optical system that combines light from two light sources among the light sources by the first illumination optical system, and converts the combined light into P-polarized light or S-polarized light;
A polarization conversion optical system for converting light from one of the three or more light sources other than the two light sources into S-polarized light or P-polarized light;
A polarizing element that re-polarizes and combines both of the light and the polarized light obtained by converting the light from the other one light source;
Further, when another light source is present, a polarization conversion optical system that converts light from the other light source into P-polarized light or S-polarized light, and converts the light that has been re-polarized and combined into S-polarized light or P-polarized light. A polarization conversion optical system, and a polarization element that combines and combines these converted lights, and repeatedly performs polarization multiplexing in the same manner, thereby performing a triple or more multi-polymerization wave. Is.
[0029]
By applying a lamp as the above-mentioned “light source”, a lamp light source used in the exposure head of the present invention can be configured, and such a lamp light source can generate a larger amount of light that has been combined with a spatial light modulator. Can be irradiated.
[0030]
The exposure apparatus of the present invention can also employ the configuration of the image recording apparatus proposed by the present applicant in Japanese Patent Application No. 2001-213519 in order to enable adjustment of the light amount of the lamp light source. The proposed image recording apparatus includes a discharge lamp as a lamp light source, a spatial light modulation element, and light that is emitted from the discharge lamp and carries an image modulated by the spatial light modulation element. It has an imaging optical system that forms an image at an image recording position, and a light amount adjusting means that can be inserted into an optical path from the discharge lamp to the image recording position.
[0031]
In the above configuration, the light amount adjusting means is preferably a plurality of filters having different transmittances or a plurality of mirrors having different reflectances. Further, in the optical path on the discharge lamp side of the light amount adjusting means. It is preferable that wavelength selection means for removing light other than light in a predetermined wavelength range is disposed.
[0032]
Furthermore, the exposure apparatus of the present invention may employ the configuration of the image recording apparatus proposed by the applicant in the above Japanese Patent Application No. 2001-213519 in order to enable removal of light unnecessary for exposure with a simple configuration. it can. The proposed image recording apparatus includes a discharge lamp as a lamp light source, a spatial light modulation element, and light that is emitted from the discharge lamp and carries an image modulated by the spatial light modulation element. An imaging optical system that forms an image at an image recording position, and a wavelength selection unit that is disposed in an optical path from the discharge lamp to the image recording position and removes light other than a predetermined wavelength region. It is.
[0033]
In the above configuration, the light amount adjusting unit and the wavelength selecting unit preferably use a dielectric multilayer film, and the discharge lamp is preferably an ultrahigh pressure discharge lamp or a metal halide lamp.
[0034]
In the exposure head of the present invention, it is preferable to use a short arc ultra-high pressure discharge lamp proposed by the present applicant for use in an image recording apparatus in Japanese Patent Application No. 2001-214829 as a lamp light source. As such a short arc ultra-high pressure discharge lamp, the mercury vapor pressure at the time of lighting is particularly 8 × 10. ⁶ It is desirable to use a material satisfying at least one of Pa or more and an interelectrode distance of 2.5 mm or less.
[0035]
When using the above short arc super high pressure discharge lamp, the exposure apparatus according to the present invention,
A function of monitoring individual total lighting time of the short arc ultra-high pressure discharge lamp;
As a result of monitoring, for a short arc type ultra-high pressure discharge lamp whose total lighting time has exceeded a first predetermined time set in advance, this is output, and further, a second predetermined time with a total lighting time set in advance. It is desirable to provide a configuration that makes it impossible to light a short arc type ultra-high pressure discharge lamp that has exceeded the time.
[0036]
Furthermore, at the time of lighting of the short arc ultra high pressure discharge lamp, it has a function of monitoring the lighting state of each short arc ultra high pressure discharge lamp,
As a result of monitoring, for short arc ultra high pressure discharge lamps that have been confirmed to be unlit, the corresponding short arc ultra high pressure discharge lamp is turned off, and the short arc ultra high pressure discharge lamp is not lit. It is also preferable to adopt a configuration that outputs.
[0037]
Furthermore, in the exposure apparatus of the present invention, the stability of the light source lamp is not disturbed, and the two-dimensional spatial light modulator is prevented from being deteriorated by the illumination light, and its lifetime is improved, so that there is little failure and reliability. For the purpose of realizing high image exposure, the configuration proposed by the present applicant in Japanese Patent Application No. 2001-203316 may be employed. In this configuration, in the image exposure apparatus that exposes the photosensitive material with the light that is modulated by the two-dimensional spatial light modulation element, the illumination light emitted from the light source according to the spectral sensitivity of the photosensitive material, the illumination light is emitted during non-image exposure. An optical system is provided so as not to irradiate the two-dimensional spatial light modulator.
[0038]
【The invention's effect】
Since the exposure head according to the present invention is provided with one lamp light source for each of the plurality of spatial light modulation elements, one common to the plurality of spatial light modulation elements as described above. Compared with the conventional exposure head provided with the lamp light source under the premise that the total exposure amount is the same, the lamp light source having a lower output can be used. As a result, the exposure head of the present invention is formed at a lower cost than the above-described conventional exposure head, and a long lamp life can be secured.
[0039]
The above points will be described more specifically. Taking a mercury lamp as an example, a 200 W mercury lamp is currently available for several thousand to 10,000 yen. If an output of 5 kW is desired and 25 of these 200 W mercury lamps are used, the total lamp cost is 250,000 yen at the highest. On the other hand, the commercial price of a 5 kW high-power mercury lamp is currently about 300,000 yen, and using a plurality of low-power lamp light sources as in the present invention makes it possible to produce an exposure head at a low cost. This tendency becomes more prominent when the desired output is high. For example, if an output of 10 kW is desired and the 50 200 W mercury lamps are used, the total lamp cost is 500,000 yen at the highest. On the other hand, the commercial price of a 10 kW high-power mercury lamp is currently about 800,000 yen.
[0040]
On the other hand, the lifetime of the 200 W mercury lamp (defined as the usage time at which the output is halved) is about 5000 hours, whereas the lifetimes of the 5 kW and 10 kW high output mercury lamps are about 1000 hours and 500 hours, respectively. It is clear that the use of a plurality of low-power lamp light sources as in the present invention is advantageous in terms of lamp life.
[0041]
Further, in the exposure head of the present invention, unlike the case of using the above-described fiber bundle, the coupling efficiency of the light emitted from the lamp light source to the fiber does not matter, and thus the light emitted from the lamp light source is more effective. Can be used to reduce power consumption.
[0042]
In particular, the exposure head according to the present invention includes a control unit that controls each of the plurality of pixel units, which is smaller than the total number of the pixel units, based on a control signal generated according to the exposure information. In this case, the number of pixel units to be controlled is reduced, and the transfer rate of the control signal is shorter than when the control signals of all the pixel units are transferred. Thereby, the light modulation speed can be increased and high-speed exposure becomes possible.
[0043]
The exposure head is relatively moved in a direction (sub-scanning direction) intersecting the predetermined direction with respect to the exposure surface, but the pixel portion controlled by the control unit has a length in a direction corresponding to the predetermined direction. If the pixel portion is included in a region longer than the length in the direction crossing the predetermined direction, the number of exposure heads to be used can be reduced.
[0044]
Further, the exposure head of the present invention particularly corrects the light amount distribution of the light emitted from the lamp light source so as to be substantially uniform on the spatial light modulator between the lamp light source and the spatial light modulator. When the optical system is provided, it is possible to illuminate the spatial light modulator with light having a substantially uniform light amount distribution without reducing the light use efficiency. Thereby, it is possible to prevent exposure unevenness and to perform high-quality image exposure.
[0045]
Since the exposure apparatus according to the present invention uses the above-described exposure head according to the present invention, the exposure apparatus is formed at a low cost, has a long lamp life, and can keep the power consumption low. .
[0046]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0047]
[Configuration of exposure apparatus]
FIG. 1 shows a perspective shape of an exposure apparatus according to an embodiment of the present invention.
As shown in the figure, the exposure apparatus includes a flat stage 152 that holds a sheet-like photosensitive material 150 by adsorbing to the surface. Also, two guides 158 extending along the stage moving direction are installed on the upper surface of the thick plate-shaped installation table 156 supported by the four legs 154. The stage 152 is 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 apparatus is provided with a drive device (not shown) for driving the stage 152 along the guide 158.
[0048]
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 ends of the U-shaped gate 160 is fixed to both side surfaces of the installation table 156. A scanner 162 is provided on one side of the gate 160, and a plurality of (for example, two) 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 each 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.
[0049]
As shown in FIGS. 2 and 3B, the scanner 162 includes a plurality of (for example, 14) exposure heads 166 arranged in an approximately matrix of m rows and n columns (for example, 3 rows and 5 columns). . In this example, four exposure heads 166 are arranged in the third row in relation to the width of the photosensitive material 150. In the case where individual exposure heads arranged in the m-th row and the n-th column are shown, the exposure head 166 is used. _mn Is written.
[0050]
An exposure area 168 by the exposure head 166 has a rectangular shape with a short side in the sub-scanning direction. Accordingly, as the stage 152 moves, a strip-shaped exposed area 170 is formed in the photosensitive material 150 for each exposure head 166. In addition, when showing the exposure area by each exposure head arranged in the mth row and the nth column, the exposure area 168 is shown. _mn Is written.
[0051]
Further, as shown in FIGS. 3A and 3B, each of the exposure heads in each row arranged in a line so that the strip-shaped exposed regions 170 are arranged in the direction orthogonal to the sub-scanning direction without gaps. In the arrangement direction, they are shifted by a predetermined interval (natural number times the long side of the exposure area, twice in this embodiment). Therefore, the exposure area 168 in the first row ₁₁ And exposure area 168 ₁₂ The portion that cannot be exposed between the exposure area 168 and the exposure area 168 in the second row ₂₁ And exposure area 168 in the third row ₃₁ And can be exposed.
[0052]
Exposure head 166 ₁₁ ~ 166 _mn 4 and 5, each includes a digital micromirror device (DMD) 50 as a spatial light modulation element that modulates an incident light beam for each pixel in accordance with image data. Yes. 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 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.
[0053]
On the light incident side of the DMD 50, there is one mercury lamp 66, a lens system 67 for condensing the light emitted from the mercury lamp 66 on the DMD 50 after correcting the light amount distribution, and light passing through the lens system 67. A mirror 69 that reflects toward the DMD 50 is arranged in this order. In FIG. 4, the lens system 67 is schematically shown.
[0054]
As shown in FIG. 5, the lens system 67 passes through the collimator lens 71, which collimates the light emitted from the filament 66a of the mercury lamp 66 and collimated to the front side by the reflector 66b. The micro fly's eye lens 72 inserted in the optical path of the light, another micro fly's eye lens 73 disposed so as to face the micro fly's eye lens 72, and the front of the micro fly eye lens 73, that is, on the mirror 69 side. The field lens 74 is arranged. The micro fly's eye lenses 72 and 73 are formed by arranging a large number of micro lens cells vertically and horizontally, and light passing through each of the micro lens cells is incident on the DMD 50 in a state where they overlap each other. The light quantity distribution of the irradiated light is made uniform.
[0055]
On the light reflection side of the DMD 50, a lens system 51 that forms an image of the light reflected by the DMD 50 on the scanning surface (exposed surface) 56 of the photosensitive material 150 is disposed. The lens system 51 is disposed so that the DMD 50 and the exposed surface 56 are in a conjugate relationship. Although this lens system 51 is schematically shown in FIG. 4, as shown in detail in FIG. 5, an enlarged image forming optical system composed of two lenses 52 and 54 and two lenses 57 and 58 are used. An imaging optical system, a microlens array 55 inserted between these optical systems, and an aperture array 59. The microlens array 55 includes a large number of microlenses 55a corresponding to the pixels of the DMD 50. The aperture array 59 is formed by forming a large number of apertures 59a corresponding to the microlenses 55a of the microlens array 55.
[0056]
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. The reflectance of the micromirror 62 is 90% or more. A silicon gate CMOS SRAM cell 60 manufactured by a normal semiconductor memory manufacturing process is disposed directly below the micromirror 62 via a support including a hinge and a yoke. The entire structure is monolithic (integrated type). ).
[0057]
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. .
[0058]
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.
[0059]
Further, it is preferable that the DMD 50 is arranged with a slight inclination so that the short side forms a predetermined angle θ (for example, 0.1 ° to 5 °) with the sub-scanning direction. 8A shows the scanning trajectory of the reflected light image (exposure beam) 53 by each micromirror when the DMD 50 is not tilted, and FIG. 8B shows the scanning trajectory of the exposure beam 53 when the DMD 50 is tilted. Show.
[0060]
In the DMD 50, a number of micromirror arrays in which a large number (for example, 800) of micromirrors are arranged in the longitudinal direction are arranged in a large number (for example, 600 sets) in the short direction. As shown, by tilting the DMD 50, the pitch P of the scanning locus (scanning line) of the exposure beam 53 by each micromirror is shown. ₁ However, the pitch P of the scanning line when the DMD 50 is not inclined. ₁ It becomes narrower and the resolution can be greatly improved. Since the tilt angle of the DMD 50 is very small, the scanning width W when the DMD 50 is tilted. ₁ And the scanning width W when the DMD 50 is not inclined. ₂ Is substantially the same.
[0061]
Further, the same scanning line is overlapped and exposed (multiple exposure) by different micromirror rows. In this way, by performing multiple exposure, it is possible to control a minute amount of the exposure position and to realize high-definition exposure. Further, joints between a plurality of exposure heads arranged in the main scanning direction can be connected without a step by controlling a very small amount of exposure position.
[0062]
Note that the same effect can be obtained by arranging the micromirror rows in a staggered manner by shifting the micromirror rows by a predetermined interval in a direction orthogonal to the sub-scanning direction instead of tilting the DMD 50.
[0063]
[Operation of exposure apparatus]
Next, the operation of the exposure apparatus will be described.
[0064]
For example, light having a wavelength band of 360 to 420 nm emitted from the mercury lamp 66 shown in FIGS. 4 and 5 is irradiated to the DMD 50 after the light amount distribution is uniformized through the lens system 67 as described above. Image data corresponding to the exposure pattern is input to a controller (not shown) connected to the DMD 50 and is 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).
[0065]
1 is moved at a constant speed along the guide 158 from the upstream side to the downstream side of the gate 160 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 as the stage 152 passes under the gate 160, the image data stored in the frame memory is sequentially read for a plurality of lines. Based on the read image data, a control signal is generated for each exposure head 166 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.
[0066]
When the light from the mercury lamp 66 is applied to the DMD 50, the light reflected by the on-state micromirrors of the DMD 50 is collected by the lens system 51 and focused on the exposed surface 56 of the photosensitive material 150. In this manner, the light emitted from the mercury lamp 66 is turned on / off for each micromirror of the DMD 50, and the photosensitive material 150 is exposed in a pixel unit (exposure area 168) that is substantially the same as the number of used pixels of the DMD 50. Further, when the photosensitive material 150 is moved at a constant speed together with the stage 152, the photosensitive material 150 is sub-scanned in the direction opposite to the stage moving direction by the scanner 162, and a strip-shaped exposed region 170 is formed for each exposure head 166. It is formed.
[0067]
Here, as shown in FIGS. 10A and 10B, in this embodiment, the DMD 50 has 600 micromirror arrays in which 800 micromirrors are arranged in the main scanning direction, and 600 sets are arranged in the subscanning direction. However, in the present embodiment, control is performed so that only a part of micromirror rows (for example, 800 × 200 rows) are driven by the controller.
[0068]
At that time, as shown in FIG. 10A, a micromirror array arranged at the center of the DMD 50 may be used. As shown in FIG. 10B, the micromirror arranged at the end of the DMD 50 may be used. A mirror row may be used. In addition, when a defect occurs in some of the micromirrors, the micromirror array to be used may be appropriately changed depending on the situation, such as using a micromirror array in which no defect has occurred.
[0069]
Since the data processing speed of the DMD 50 is limited and the modulation speed per line is determined in proportion to the number of pixels used, the modulation speed per line can be increased by using only a part of the micromirror rows. Get faster. On the other hand, in the case of an exposure method in which the exposure head is continuously moved relative to the exposure surface, it is not necessary to use all the pixels in the sub-scanning direction.
[0070]
For example, when only 300 sets are used in 600 micromirror rows, modulation can be performed twice as fast per line as compared to the case of using all 600 sets. Further, when only 200 sets of 600 micromirror arrays are used, modulation can be performed three times faster per line than when all 600 sets are used. That is, an area of 500 mm in the sub-scanning direction can be exposed in 17 seconds. Further, when only 100 sets are used, modulation can be performed 6 times faster per line. That is, an area of 500 mm in the sub-scanning direction can be exposed in 9 seconds.
[0071]
The number of micromirror rows to be used, that is, the number of micromirrors arranged in the sub-scanning direction is preferably 10 or more and 300 or less, and more preferably 10 or more and 200 or less. Since the area per micromirror corresponding to one pixel is 15 μm × 15 μm, when converted to the use area of DMD50, an area of 12 mm × 150 μm or more and 12 mm × 4.5 mm or less is preferable, and 12 mm × 150 μm or more. And the area | region of 12 mm x 3 mm or less is more preferable.
[0072]
If the number of micromirror rows to be used is in the above range, the light emitted from the mercury lamp 66 can be converted into substantially parallel light by the lens system 67 and irradiated to the DMD 50.
The irradiation area where the DMD 50 is irradiated with light preferably coincides with the use area of the DMD 50. If the irradiation area is wider than the use area, the light use efficiency is lowered.
[0073]
On the other hand, the diameter of the light beam condensed on the DMD 50 in the sub-scanning direction needs to be reduced according to the number of micromirrors arranged in the sub-scanning direction by the lens system 67, but the number of micromirror rows to be used. Is less than 10, it is not preferable because the angle of the light beam incident on the DMD 50 increases and the depth of focus of the light beam on the scanning surface 56 becomes shallow. Further, the number of micromirror rows to be used is preferably 200 or less from the viewpoint of modulation speed.
[0074]
When the sub scanning of the photosensitive material 150 by the scanner 162 is completed and the rear end of the photosensitive material 150 is detected by the detection sensor 164, the stage 152 is moved along the guide 158 by the driving device (not shown) on the most upstream side of the gate 160. Returned to the origin at the point, and again moved along the guide 158 from the upstream side to the downstream side of the gate 160 at a constant speed.
[0075]
As described above, since the exposure apparatus of the present embodiment is provided with one mercury lamp 66 for each of the plurality of DMDs 50, one common mercury for the plurality of DMDs 50. Comparing the exposure apparatus provided with the lamp 66 and the assumption that the total exposure amount is the same, it is possible to use a mercury lamp 66 having a lower output. As a result, the exposure apparatus of the present embodiment can be formed at a lower cost and can ensure a long lamp life. The detailed reason is as described above.
[0076]
In addition, unlike the case of using the fiber bundle described above, the exposure apparatus of the present embodiment does not matter the coupling efficiency of the light emitted from the lamp light source to the fiber, and therefore the light emitted from the lamp light source is not a problem. It can be used more effectively to reduce power consumption.
[0077]
Furthermore, the exposure apparatus of the present embodiment includes a DMD 50 in which 600 sets of micromirror arrays in which 800 micromirrors are arranged in the main scanning direction are arranged in the subscanning direction. Since the control is performed so that only the columns are driven, the modulation speed per line becomes faster than when all the micromirror columns are driven. This enables high-speed exposure.
[0078]
In the present embodiment, as shown in FIG. 5, the following effects can be obtained by using the magnification imaging optical system including the two lenses 52 and 54, the microlens array 55, and the aperture array 59. Can also be obtained.
[0079]
That is, in this configuration, the cross-sectional area of the light beam reflected by the DMD 50 in the ON direction is magnified several times (for example, twice) by the magnification imaging optical system including the lenses 52 and 54. The light that has passed through the magnification imaging optical system is condensed by each microlens 55a of the microlens array 55 corresponding to each pixel of the DMD 50, and passes through the corresponding aperture 59a of the aperture array 59. The light that has passed through the aperture 59 is focused on the exposed surface 56 by the lenses 57 and 58, and an image by this light is formed on the exposed surface 56.
[0080]
In this imaging optical system, the light reflected by the DMD 50 is magnified several times by the lenses 52 and 54 and projected onto the exposed surface 56, so that the entire image area is widened. At this time, if the microlens array 55 and the aperture array 59 are not arranged, as shown in FIG. 13A, one pixel size (spot size) of each beam spot BS projected onto the exposed surface 56 is exposed. It becomes larger according to the size of the area 468, and the MTF (Modulation Transfer Function) characteristic of the exposure area 468, that is, the sharpness of the exposed image is lowered.
[0081]
On the other hand, in the present embodiment in which the microlens array 55 and the aperture array 59 are arranged, the light reflected by the DMD 50 is condensed corresponding to each pixel of the DMD 50 by each microlens 55a of the microlens array 55. Is done. As a result, as shown in FIG. 13B, even when the exposure area is enlarged, the spot size of each beam spot BS can be reduced to a desired size (for example, 10 μm × 10 μm), and the MTF characteristics are obtained. It is possible to perform high-definition exposure while preventing a decrease in the image quality. The exposure area 468 is tilted because the DMD 50 is tilted and arranged in order to eliminate a gap between pixels.
[0082]
Further, even if the beam is thick due to the aberration of the microlens 55a, the aperture 59a can shape the beam so that the spot size on the exposed surface 56 becomes a constant size, and also supports each pixel. By passing the aperture 59a provided in this manner, crosstalk between adjacent pixels can be prevented.
[0083]
Next, a modification of the exposure apparatus described above will be described.
[0084]
[Applications of exposure equipment]
The exposure apparatus described above is, for example, exposure of a dry film resist (DFR) in a manufacturing process of a printed wiring board (PWB) and a color filter in a manufacturing process of a liquid crystal display (LCD). It can be suitably used for applications such as formation, DFR exposure in a TFT manufacturing process, and DFR exposure in a plasma display panel (PDP) manufacturing process.
[0085]
When exposing a liquid resist used for patterning a TFT and a liquid resist used for patterning a color filter, in order to eliminate sensitivity reduction (desensitization) due to oxygen inhibition, the exposure is performed in a nitrogen atmosphere. It is preferable to expose the exposure material. Exposure in a nitrogen atmosphere suppresses oxygen inhibition of the photopolymerization reaction, increases the sensitivity of the resist, and enables high-speed exposure.
[0086]
In the exposure apparatus, either a photon mode photosensitive material in which information is directly recorded by exposure or a heat mode photosensitive material in which information is recorded by heat generated by exposure can be used.
[0087]
[Other spatial light modulators]
In the above embodiment, the exposure head provided with the DMD as the spatial light modulation element has been described. For example, a MEMS (Micro Electro Mechanical Systems) type spatial light modulation element (SLM; Spatial Light Modulator), an electro-optical effect, and the like. It is also possible to use a spatial light modulation element other than the MEMS type, such as an optical element (PLZT element) that modulates transmitted light by a light source and a liquid crystal light shutter (FLC).
[0088]
Note that MEMS is a general term for a micro system that integrates micro-sized sensors, actuators, and control circuits based on a micro-machining technology based on an IC manufacturing process. A MEMS-type spatial light modulator is an electrostatic force. It means a spatial light modulation element driven by an electromechanical operation using
[0089]
[Other exposure methods]
In the above embodiment, as shown in FIG. 11, the entire surface of the photosensitive material 150 is exposed by one scan in the X direction by the scanner 162. However, as shown in FIGS. Then, after scanning the photosensitive material 150 in the X direction by the scanner 162, the scanner 162 is moved one step in the Y direction and scanned in the X direction. The entire surface 150 may be exposed. In this example, the scanner 162 includes 18 exposure heads 166.
[0090]
[Other embodiments]
Here, an example of a lamp light source used in place of the mercury lamp 66 shown in FIGS. 4 and 5 will be described with reference to FIG. As shown in the figure, the lamp light source 310 of this example combines light from the first light source 320 and the second light source 330 by a polarization beam splitter 340 that is a polarizing element.
[0091]
In the optical path from the first light source 320 to the polarization beam splitter 340, the first lens array plate 324 and the polarization conversion element 326 that converts all the light from the first light source 320 into P-polarized light in order from the light source 320 side. , And a second lens array plate 328 that converts the light polarized by the polarization conversion element 326 into a parallel light beam.
[0092]
Similarly, in the optical path from the second light source 330 to the polarization beam splitter 340, all the light from the first lens array plate 334 and the second light source 330 is converted into S-polarized light in order from the light source 330 side. A polarization conversion element 336 and a second lens array plate 338 that converts the light polarized by the polarization conversion element 336 into a parallel light beam are disposed.
[0093]
The first light source 320 and the second light source 330 are respectively lamps 321 and 331 that emit radial rays, and reflectors (concave mirrors) that emit radiation rays emitted from the lamps 321 and 331 as substantially parallel beam bundles. 322 and 332.
[0094]
As the lamps 321 and 331, a halogen lamp, a metal halide lamp, a xenon lamp, or a discharge lamp such as an ultraviolet lamp or a mercury lamp is used. The reflectors 322 and 332 are preferably parabolic mirrors, but are not limited to parabolic mirrors, and may be elliptical mirrors, spherical mirrors, or the like.
[0095]
Each of the first lens array plates 324 and 334 is a lens array extending in at least a one-dimensional direction. As shown in FIG. 14, the first lens array plates 324 and 334 are respectively formed from unpolarized light (random polarized light) emitted from the light sources 320 and 330, respectively. Thereafter, a linear or dot array is generated in the vicinity of the side focal plane. The lens array plates 324 and 334 are configured, for example, by arranging plano-convex small lenses having a substantially rectangular outline in a one-dimensional direction or a two-dimensional direction in a matrix.
[0096]
The polarization conversion element 326 arranged in the optical path of the light from the first light source 320 has a linear or dotted array pitch generated near the rear focal plane by the first lens array plate 324. All of the light emitted from the first light source 320 having substantially the same pitch and disposed in the vicinity of the focal plane is converted into P-polarized light.
[0097]
FIG. 15 shows an enlarged configuration of a part of the polarization conversion element 326. As shown in the figure, the polarization conversion element 326 includes a polarization separation surface 326a and a total reflection surface 326b coated with a dielectric multilayer film that separates P-polarized light and S-polarized light, and a λ / 2 wavelength plate 326c. The In FIG. 15, a double-pointed arrow symbol and a symbol with a dot in a white circle represent the polarization direction of each light. That is, the double-pointed arrow symbol represents the polarization in the left-right direction in the figure, and the symbol with a dot in the white circle represents the polarization in the direction perpendicular to the drawing sheet.
[0098]
The light beam 350 that has passed through the first lens array plate 324 and entered the polarization conversion element 326 is separated into two linearly polarized light components that are orthogonal to each other at the polarization separation surface 326a. That is, in the light beam 350, the P-polarized light 351 passes through the polarization separation surface 326a, and the S-polarized light 352 is reflected by the polarization separation surface 326a.
[0099]
The P-polarized light 351 that has passed through the polarization separation surface 326a is emitted from the polarization conversion element 326 as it is. The S-polarized light 352 reflected by the polarization separation surface 326a is reflected by the reflection surface 326b, and then passes through the λ / 2 wavelength plate 326c, thereby being converted to P-polarized light and emitted from the polarization conversion element 326. . Therefore, the light beam 350 incident on the polarization conversion element 326 is all converted to P-polarized light and emitted.
[0100]
Further, the polarization conversion element 336 arranged in the optical path of the light from the second light source 330 is a linear or dot array generated near the rear focal plane by the first lens array plate 334. All of the light emitted from the second light source 330 having a pitch substantially equal to the pitch and disposed in the vicinity of the focal plane is converted into S-polarized light.
[0101]
FIG. 16 shows an enlarged configuration of a part of the polarization conversion element 336. As shown in the figure, the polarization conversion element 336 includes a polarization separation surface 336a and a reflection surface 336b coated with a dielectric multilayer film that separates P-polarized light and S-polarized light, and a λ / 2 wavelength plate 336c. . In FIG. 16, the double-pointed arrow symbol and the symbol with a dot in the white circle represent the polarization directions of the respective lights as in FIG. 15.
[0102]
The light beam 360 that has passed through the first lens array plate 334 and entered the polarization conversion element 336 is separated into two linearly polarized light components that are orthogonal to each other at the polarization separation surface 336a. That is, the P-polarized light 361 that has passed through the polarization splitting surface 336 a in the light beam 360 is then converted into S-polarized light by passing through the λ / 2 wavelength plate 336 c and is emitted from the polarization conversion element 336.
[0103]
On the other hand, the S-polarized light 362 reflected by the polarization separation surface 336a is totally reflected by the total reflection surface 336b and is emitted from the polarization conversion element 336 as it is. Accordingly, the light beam 360 incident on the polarization conversion element 336 is all converted to S-polarized light and emitted.
[0104]
As described with reference to FIGS. 15 and 16, P-polarized light and S-polarized light can be selectively generated by shifting the phases of the first lens array plate and the polarization conversion element.
[0105]
Returning to FIG. 14 again, the second lens array plate 328 arranged in the optical path of the light from the first light source 320 has a pitch of about ½ of the pitch of the polarization conversion element 326, and its front focal point. The surface is disposed so as to substantially coincide with the rear focal plane of the first lens array plate 324. As a result, the light beam emitted from the second lens array plate 328 becomes substantially parallel light, and this parallel light beam is incident on the polarization beam splitter 340.
[0106]
Similarly, the second lens array plate 338 disposed in the optical path of the light from the second light source 330 has a pitch that is approximately ½ of the pitch of the polarization conversion element 336, and its front focal plane is the above-mentioned focal plane. The first lens array plate 334 is disposed so as to substantially coincide with the rear focal plane, and the light beam emitted from the second lens array plate 328 enters the polarization beam splitter 340 as a substantially parallel light beam.
[0107]
The polarization beam splitter 340 is a polarization element that performs multiplexing while suppressing the loss of light quantity. The polarization beam splitter 340 emits light that has been emitted from the first light source 320 and converted to P-polarized light by the polarization conversion element 326 and emitted from the second light source 330. Then, the light converted into S-polarized light by the polarization conversion element 336 is multiplexed.
[0108]
The polarization beam splitter 340 has a polarization separation surface 340a having an optical characteristic of reflecting S-polarized light and transmitting P-polarized light. Accordingly, the P-polarized light incident on the polarization beam splitter 340 from the first light source 320 side is transmitted through the polarization separation surface 340a and is emitted as it is. In addition, the S-polarized light incident on the polarization beam splitter 340 from the second light source 330 side is reflected by the polarization separation surface 340a and emitted in the same direction as the P-polarized light, whereby both polarized lights are combined.
[0109]
The light beams thus combined are made incident on the irradiation lens system 67 in the configuration shown in FIG. Thereby, the DMD 50 is irradiated with a large amount of light.
[0110]
As shown in FIG. 17, the second lens array plates 328 and 338 are formed by alternately arranging lenses 328a (338a) having a long focal length and lenses 328b (338b) having a short focal length. It is preferable that the focal length is different. By doing so, the difference in the optical path length of the light passing through the polarization conversion element 326 or 336 can be corrected, and the parallelism of the light emitted from the second lens array plate 328 or 338 becomes good. The multiplexing efficiency is improved, and this is particularly effective in the case of a multi-polymerization wave that combines light from three or more light sources described later.
[0111]
In addition, as shown in FIG. 18, an optical system that converts light from the light source into polarized light and enters the polarization beam splitter includes a first lens array plate 342, a polarization conversion element 344, and a second lens array plate 346. These may be integrated and configured by, for example, adhesion.
[0112]
This is because the multiplexing efficiency changes due to a change in the angle of the incident light beam on the lens array plate, or a change in the relative position of the first and second lens array plates and the polarization conversion element due to temperature, time, etc. It is. For example, if the phase of the first lens array plate and the polarization conversion element is shifted, P-polarized light becomes S-polarized light, and there is a case where multiplexing as expected cannot be performed. Further, if the phases of the first lens array plate and the second lens array plate are deviated, the emission direction of the light beam emitted from the second lens array plate is deviated, and it may be impossible to synthesize well.
[0113]
Therefore, by making the polarization conversion element or the like into an integrated configuration as described above, it is possible to suppress a change in the multiplexing efficiency and obtain illumination light that is stable with respect to the light amount and the light amount distribution.
[0114]
Next, a case where light from three light sources is combined will be described. FIG. 19 shows a configuration for multiplexing light from three light sources. As shown in the figure, the illumination device 400 for combining three waves of this example has three light sources 420, 430 and 450, and two polarization beam splitters 440 and 460. First, the first light source The light from 420 and the light from the second light source 430 are combined by the first polarization beam splitter 440. Next, the light that has been combined and the light from the third light source 450 are combined with the second light. The beam is multiplexed by the polarization beam splitter 460.
[0115]
The part where the light from the first light source 420 and the light from the second light source 430 are combined by the first polarizing beam splitter 440 is the same as the example of FIG.
[0116]
That is, the first light source 420 includes a lamp 421 and a reflector 422, and the light emitted from the first light source 120 is converted into, for example, P-polarized light by the polarization conversion element 126 via the first lens array plate 124. The converted light is converted into a parallel light beam by the second lens array plate 428 and is incident on the first polarization beam splitter 440.
[0117]
On the other hand, the second light source 430 includes a lamp 431 and a reflector 432, and light emitted from the second light source 430 is converted into, for example, S-polarized light by the polarization conversion element 436 via the first lens array plate 434. The light is converted into a parallel light beam by the second lens array plate 438 and is incident on the first polarization beam splitter 440 from a direction substantially orthogonal to the light from the first light source 420.
[0118]
The first polarization beam splitter 440 has a polarization separation surface 440a that transmits P-polarized light and reflects S-polarized light. Accordingly, the first polarization beam splitter 440 transmits the P-polarized light from the first light source 420 as it is, and the S-polarized light from the second light source 430 is reflected by the polarization separation surface 440a, and the P-polarized light and By emitting in the same direction, both these polarized lights are multiplexed.
[0119]
The light emitted from the first polarization beam splitter 440 passes through the first lens array plate 444, the polarization conversion element 446, and the second lens array plate 448, and is converted again into a P-polarized light beam. The light enters the second polarization beam splitter 460.
[0120]
The third light source 450 includes a lamp 451 and a reflector 452, and the light emitted from the third light source 450 is converted into, for example, S-polarized light by the polarization conversion element 456 via the first lens array plate 454. The converted light is converted into a parallel light beam by the second lens array plate 458 and is incident on the second polarizing beam splitter 460 from a direction substantially orthogonal to the light emitted from the first polarizing beam splitter 440.
[0121]
The second polarization beam splitter 460 has a polarization separation surface 460a having characteristics of transmitting P-polarized light and reflecting S-polarized light. Accordingly, the second polarization beam splitter 460 transmits the P-polarized light from the first polarization beam splitter 440 as it is, and the S-polarized light from the third light source 450 is reflected by the polarization separation surface 460a, so that the P By emitting in the same direction as the polarized light, these both polarized lights are combined. As described above, the lights from the three light sources are combined.
[0122]
The light that is combined and emitted from the second polarization beam splitter 460 is incident on the irradiation lens system 67 shown in FIG. 5, for example, via a normal integrator optical system composed of lens array plates 462 and 464. . Thereby, the DMD 50 is irradiated with a large amount of light.
[0123]
In the illumination device 400, each of the second lens array plates 428, 438, 448 and 458 has a configuration in which the focal lengths of the individual lenses are different from each other as shown in FIG. Since the parallelism of the emitted light is improved, the luminous flux is hardly spread, and the multiplexing efficiency is kept good even if the multiplexing is repeated.
[0124]
Next, an illumination device that combines light from four light sources will be described. As illustrated in FIG. 20, the illumination device 200 of this example includes four light sources 210, 220, 230, and 240 and three polarization beam splitters 250, 260, and 270. Reference numerals 212, 222, 232, 242, 252, and 282 are optical systems each including a first lens array plate, a polarization conversion element, and a second lens array plate. It is converted into an S-polarized parallel light beam and emitted.
[0125]
The first polarization beam splitter 250 is emitted from the first light source 210 and is emitted from the optical system 212 into, for example, a P-polarized parallel light beam and emitted from the second light source 220. For example, the light converted into the S-polarized parallel light beam is multiplexed.
[0126]
Further, the second polarization beam splitter 260 is emitted from the third light source 230 and emitted from the fourth light source 240 and the light converted into, for example, P-polarized parallel light by the optical system 232, and the optical system 242. Thus, for example, the light converted into the S-polarized parallel light beam is multiplexed.
[0127]
The third polarization beam splitter 270 combines the light combined by the first polarization beam splitter 250 with the optical system 252, for example, light converted into an S-polarized parallel light beam and the second polarization beam splitter 260. The optical system 262 combines the light that has been converted into, for example, P-polarized parallel light flux.
[0128]
In the polarization multiplexing apparatus described above, the optical path lengths from the first light source to the fourth light source to the third polarization beam splitter 270 are all set to be equal.
[0129]
As described above, the light from the four light sources is finally combined. By repeating multiplexing in this way, it is generally possible to perform n-fold (n ≧ 3) multiplexing.
[0130]
Moreover, the parallel light can be improved by using the lens array plate in which the lenses having different focal lengths are arranged every other time as the polarized light by the polarization conversion element. Wave efficiency can be improved.
[0131]
Next, an image exposure apparatus according to another embodiment of the present invention will be described with reference to FIG. The image exposure apparatus 501 includes a so-called reflected light point sequence generated by a DMD (digital micromirror device) that is a two-dimensional spatial light modulation element irradiated with an illumination light beam as a two-dimensionally arranged light source group, and a so-called light source group. This is an apparatus for recording an image by scanning and exposing a recording medium two-dimensionally using an external drum (outer drum).
[0132]
21A and 21B, an image exposure apparatus 501 includes an illumination light source (lamp light source) 510, a DMD 512 that receives an illumination light beam emitted from the illumination light source 510, a collimator lens optical system 514, and an optical deflector. (Deflector) 516, focusing lens optical system 518, sub-scanning drive system 520, and external drum (outer drum) 522 (hereinafter simply referred to as drum 522). A recording medium 524 is wound around the outer surface of the drum 522.
[0133]
The illumination light source 510 includes a lamp 510a and a reflector 510b, and various lamps corresponding to the spectral sensitivity of the target recording medium can be used as the lamp 510a. For example, if the recording medium is a film for plate making or a conventional PS plate sensitive to visible light or ultraviolet light, an ultrahigh pressure mercury lamp, a metal halide lamp, or the like may be used.
[0134]
In addition, an LED, a halogen lamp, a xenon lamp, or the like can be used in accordance with the recording medium.
[0135]
The illumination light emitted from the illumination light source 510 passes through the lens group 530, is reflected by the mirror 32, and is incident on the DMD 512. _in It becomes. Although the lens group 530 is schematically shown, for example, the lens system 67 shown in FIG. 5 may be applied in detail.
[0136]
As described above, the DMD 512 can freely switch the micromirror to a rotation angle of +10 degrees or −10 degrees, and can emit light L in two deflection directions. _on (On light), L _off (Off light) can be emitted. The rotation angle of the micromirror is switched using an electrostatic force, and the exposure is turned on / off for each micromirror to modulate the light and generate the emitted light that carries the image. That is, each micromirror of the DMD 512 corresponds to the pixel of the image to be formed, and the arrangement interval of each micromirror corresponds to the pixel pitch of the image formed by the light source group. Therefore, it can be said that the micromirrors constituting the DMD 512 are pixels on the mirror array surface of the DMD 512.
[0137]
In the image exposure apparatus 501 of the illustrated example, for example, a DMD 512 having a pixel pitch of 17 μm and 1024 pixels × 1280 pixels is used. Further, the rotation direction of the drum 522 (shown by an arrow T in the figure) described later optically coincides with the direction of the 1024 pixels formed on the recording medium 524 (hereinafter, this is shown by an arrow M in the figure). The direction of the rotation axis of the drum 522 is optically coincident with the direction of the pixel row of 1280 pixels imaged on the recording medium 524 (this direction indicated by the arrow S in the figure is the sub-scanning direction). Each member is arranged so as to be in the scanning direction.
[0138]
Note that the spatial light modulation element used here is not limited to the DMD 512 as shown in the drawing, and other than this, a reflection-diffractive element (GLV (Grating Light Valve)) or the like can be used. A reflection-diffraction type element is formed of a plurality of fine ribbon-like elements having a reflecting surface, and each element is displaced in the direction perpendicular to the reflecting surface, thereby causing diffraction by reflected light reflected from the plurality of ribbon-like elements. And a device that forms emitted light in a specific direction, and is produced on a silicon chip by micromachine technology.
[0139]
The collimator lens optical system 514 makes the light reflected by the DMD 512 enter the light deflector 516 as parallel light.
[0140]
The light deflector 516 deflects the light incident through the collimator lens optical system 514 in the main scanning direction M according to the rotation of the drum 522. That is, the optical deflector 516 is driven by driving means (optical deflector driver) (not shown in FIG. 21A) so that the direction of light changes according to the rotation of the drum 522, and the drum 522 rotates. However, the image is formed at the same position on the recording medium 524. As the optical deflector 516, various devices such as a galvano scanner, a polygonal mirror, and a piezo system are preferably exemplified.
[0141]
The focusing lens optical system 518 forms an image on the recording medium 524 wound around the drum 522 by exposing the light deflected by the optical deflector 516 to expose the recording medium 524.
[0142]
Here, the collimator lens optical system 514 is disposed so that the DMD 512 is disposed at the front focal position of the collimator lens optical system 514, and the exposed portion of the recording medium 524 is at the rear focal position of the focusing lens optical system 518. As shown, a focusing lens optical system 518 is arranged so that an image is formed on the recording medium 524.
[0143]
The parallel light reflected by the DMD 512 finally forms an image on the recording medium 524 held on the surface of the drum 522. Examples of the recording medium 524 include an optical mode sensitive material and a thermal mode sensitive material. The recording medium is not particularly limited and may be a film or a plate.
[0144]
The (external) drum 522 is a cylindrical drum that holds the recording medium 524 on the outer surface and rotates in the direction indicated by the arrow T in the figure around the drum rotation axis.
[0145]
The optical systems from the illumination light source to the DMD 512, the collimator lens optical system 514, the optical deflector 516, and the focusing lens optical system 518 are integrated into a unit, and the sub-scanning drive system 520 performs sub-scanning direction (in the drawing). It is configured to move at a predetermined speed in the direction of arrow S).
[0146]
Here, the illumination optical system used to form an image in the image exposure apparatus 501 includes an illumination light source 510, a lens group 530, a mirror 532, and a DMD 512. Here, the incident light L incident on the DMD 512 _in As shown in FIG. 22, the mirror 532 and the like are adjusted so that the principal ray is inclined by 30 degrees with respect to the normal direction of the micromirror array surface of the DMD 512. Then, in the state where the rotation angle of the micromirror is +10 degrees, the emitted light L having the principal ray in the direction A inclined by -10 degrees with respect to the normal direction of the mirror arrangement surface _on Is emitted, and the emitted light L having a principal ray in the direction B inclined by −50 degrees with respect to the normal direction of the micromirror array surface in a state where the rotation angle of the micromirror is −10 degrees. _off Is ejected. Emission light L _on Passes through the collimator lens optical system 514 and is finally focused on the recording medium 524.
[0147]
As described above, incident light L with respect to DMD 512 _in The inclination angle of the incident light L is 30 degrees. _in Direction of incident chief ray and emission light L _on The angle between the principal ray deflection directions (direction A) of _on Direction of the chief ray and the exit light L _off This is to make the angle between the principal ray deflection directions (direction B) substantially equal. Here, making the angles substantially equal means that the angle difference between them is within 10 degrees.
[0148]
Thereby, the incident light L _in Can be expanded to a maximum of 40 degrees, and at a light beam angle of 40 degrees, F1.37 is obtained. _in Can be sufficiently increased.
[0149]
In this way, for the DMD in which the rotation angle of the micromirror is set to +10 degrees and −10 degrees, the emission light L _on Incident light L so that the deflection direction of the principal ray of the light beam is inclined in the normal direction of the mirror array surface. _in By setting the incident light L _in Direction of incident chief ray and emission light L _on The angle of the chief ray with respect to the deflection direction of _on Direction of the chief ray and the exit light L _off Can be made substantially equal to the angle with the principal ray deflection direction.
[0150]
The incident light L shown in FIG. _in The example of the incident angle of the principal ray is based on the premise that the rotation angle of the micromirror of the DMD 512 is +10 degrees and −10 degrees, but the present invention is not limited to this. Using a spatial light modulation element having an element that freely switches the deflection direction between at least two directions, the angle between the incident direction of the principal ray of the incident light and the first deflection direction of the principal ray of the emitted light is set to The incident angle of the incident light may be set according to the spatial light modulation element so that the angle between the first deflection direction of the light beam and the second deflection direction of the main light beam of the emitted light is made substantially equal.
[0151]
In this way, the emitted light L _on Reaches the optical deflector 516, is deflected according to the deflection angle, and reaches the focusing lens optical system 518. Here, as shown in FIG. 23, the collimator lens optical system 514 is preferably arranged in parallel to the micromirror array surface of the DMD 512. Emission light L _on As described above, since the principal ray of is not perpendicular to the micromirror array surface of the DMD 512, the emitted light L _on The principal ray passes through the collimator lens optical system 514 at an angle inclined with respect to the optical axis of the collimator lens optical system 514. In such a state, the collimator lens optical system 514 is placed on the micromirror array surface of the DMD 512. This is because a good image can be formed on the recording medium 524 by arranging them in parallel.
[0152]
In the present embodiment, the incident light L _in Of the incident light L _in Direction of incident chief ray and emission light L _on However, in the present invention, the angle may be smaller than this angle. However, in order to secure a larger amount of light, the incident light L _in Of the incident light L _in Direction of incident chief ray and emission light L _on It is preferable that the angle be equal to the angle between the deflection directions of the principal rays.
[0153]
In the present embodiment, the incident light L _in Direction of incident chief ray and emission light L _on The angle between the principal ray deflection directions (direction A) of _on Direction of the chief ray and the exit light L _off The incident light L so that the angle between the principal ray deflection directions (direction B) is substantially equal. _in In this setting, as shown below, a total reflection prism is arranged in front of the micromirror array surface of the DMD 512, and this total reflection prism is used, and as shown in FIG. Incident light L shown in _in And emitted light L _on Alternatively, the emitted light L _on And emitted light L _off May be separated.
[0154]
For example, FIG. 24 shows a total reflection prism 542 having a polygonal shape having boundary surfaces 540 and 541 for performing total reflection and transmission of incident light at a predetermined critical angle.
[0155]
As shown in FIG. 24, the total reflection prism 542 has incident light L at the boundary surface 540. _in Is totally reflected and emitted light L _on At the boundary surface 541 and the emitted light L _on , And the emitted light L _off Is an optical element that totally reflects light and has boundary surfaces 540 and 541 formed in a plane with an air gap.
[0156]
That is, incident light L _in And emitted light L _on So that the incident light L can be separated. _in And emitted light L _on An angle φ formed between the separation line 546 and the normal line 543 of the boundary surface 540 is defined as a critical angle at the boundary surface 540. Similarly, the emitted light L _on And emitted light L _off So that the light can be separated. _on And emitted light L _off An angle φ ′ formed between the separation line 547 and the normal line 544 of the boundary surface 541 is defined as a critical angle at the boundary surface 541.
[0157]
With this critical angle setting, even if the luminous flux angle is θ ₁ Incident light L beyond _in Even the emitted light L _on Can be limited to a range surrounded by separation lines 546 and 547.
[0158]
In this way, by using total reflection and transmission of the boundary surfaces 540 and 541, the incident light L _in And the incident light L can be made as wide as possible. _in And emitted light L _on Optical path and emission light L _off And emitted light L _on Can be separated from each other, and each light can be completely separated. Therefore, the emitted light L _on In addition to the image created by, the contrast of the image does not decrease.
[0159]
Further, even if the incident light has a wide luminous flux, the total reflection prism 42 is used, so that the emission light L is limited to the range sandwiched between the separation lines 46 and 47. _on Therefore, the incident light L incident on the total reflection prism 42 is obtained. _in The luminous flux angle is not particularly limited. However, as much as possible, the incident light L _in Direction of incident chief ray and emission light L _on It is preferable from the viewpoint of effectively using the irradiation energy of the illumination light source that the angle is equal to or smaller than the angle between the deflection directions of the principal rays.
[0160]
Next, the operation of the image exposure apparatus 501 in FIG. 21 will be described. In this embodiment, in order to expose and record an entire image recorded on one recording medium, the entire image is divided into small parts, and this small part is referred to as an image of one frame here. . The size of this one-frame image is determined by the number of micromirrors arranged in the DMD 512, that is, the number of pixels of the image formed by the DMD 512. As described above, the DMD 512 of this embodiment is 1024 pixels × 1280 pixels, and in this case, this is the size of an image of one frame.
[0161]
In exposure recording, one frame of image data is sent from a modulation signal generator (not shown) of the DMD 512 to the DMD 512, and on / off of each micromirror of the DMD 512 is controlled according to this data. Here incident light L _in , The emitted light L due to reflection _on Is obtained. Emission light L _on Is the incident light L _in Since the light beam angle is 40 degrees, for example, the light beam is emitted at this light beam angle.
[0162]
Emission light L _on Is imaged on the recording medium 524 held on the surface of the rotating drum 522 via the collimator lens optical system 514, the optical deflector 516, and the focusing lens optical system 518.
[0163]
The drum 522 rotates at a constant speed in the direction indicated by the arrow T in the drawing. In accordance with this rotational speed, the optical deflector 516 is driven by an optical deflector driver (not shown) to deflect the light in the direction opposite to the main scanning direction M and form an image on the recording medium 524. The image is stopped on the recording medium 524 without flowing.
Then, while the drum 522 rotates for one frame, that is, for 1024 pixels in the direction opposite to the main scanning direction, or for a number of pixels less than that, recording (exposure) of this one frame image is performed.
[0164]
In the present embodiment, the light deflector 516 emits the light L according to the movement of the recording medium 524. _on Is used so that the image follows the movement of the recording medium 524 so that the image formed on the recording medium 524 is stationary with respect to the recording medium 524. However, the illumination optical system applied in the present invention is not limited to this, and the image data is changed and sent to a plurality of micromirrors of the DMD 512, and the DMD 512 is exposed a plurality of times by each micromirror. You may apply to what is called a multiple exposure system which controls, moves an image synchronizing with the motion of the recording medium 524, and makes an image stand still on the recording medium 524.
[0165]
Next, an exposure apparatus according to still another embodiment of the present invention will be described with reference to FIG. The illumination optical system 601 used in the exposure apparatus 603 of FIG. 25 converts light from two light sources 610 and 620 emitting non-polarized light into P-polarized light or S-polarized light by polarization conversion elements 615 and 625, respectively. Polarization multiplexing is performed by a polarization beam splitter 630 that is a polarization element that combines two polarized lights.
[0166]
The light sources 610 and 620 include lamps 611 and 621 as radiation light sources that emit radially unpolarized light, and reflectors (concave mirrors) 612 that emit radiation light emitted from the lamps 611 and 621 as substantially parallel beam bundles, respectively. 622. As the lamps 611 and 621, a discharge lamp such as a halogen lamp, a metal halide lamp, a xenon lamp or a mercury lamp is used. Moreover, although it is preferable to use a parabolic mirror as the reflectors 612 and 622, it is not limited to a parabolic mirror, and an elliptical mirror can also be used.
[0167]
The steps until the unpolarized light (randomly polarized light) emitted from the light sources 610 and 620 are respectively subjected to polarization conversion and combined by the polarization beam splitter 630 are the same.
[0168]
The light emitted from the light source 610 passes through the first lens array plate 613 and the second lens array plate 614 constituting the integrator optical system, and is then converted into P-polarized light by the polarization conversion element 615. The light converted into P-polarized light by the polarization conversion element 615 passes through the lenses 616 and 617 and then enters the polarization beam splitter 630.
[0169]
On the other hand, the light emitted from the light source 620 passes through the first lens array plate 623 and the second lens array plate 624 constituting the integrator optical system, and is then converted into S-polarized light by the polarization conversion element 625. After passing through the lens 627, the light enters the polarization beam splitter 630.
[0170]
The lens array plate is configured by arranging lenses having substantially the same aperture shape one-dimensionally or two-dimensionally. For example, plano-convex small lenses having a substantially rectangular outline are arranged in a one-dimensional direction or a two-dimensional direction in a matrix.
[0171]
In FIG. 26, the schematic structure of the polarization conversion element 615 is partially enlarged. The polarization conversion element 615 includes a polarization separation surface 615a and a total reflection surface 615b coated with a dielectric multilayer film that separates P-polarized light and S-polarized light, and a λ / 2 wavelength plate 615c. As described above, the polarization conversion element 615 includes a separation unit including a polarization separation surface and a total reflection surface (or a birefringent material) that separates P-polarized light and S-polarized light, and a λ / 2 wavelength plate (or λ / 4 wavelength). And a conversion unit made of a plate. The light beam 650 that has passed through the lens array plates 613 and 614 and entered the polarization conversion element 615 is separated by the polarization separation surface 615a into two linearly polarized light components that are orthogonal to each other. That is, in the light beam 650, the P-polarized light 651 passes through the polarization separation surface 615a, and the S-polarized light 652 is reflected by the polarization separation surface 615a.
[0172]
In FIG. 26, a double-headed arrow symbol and a symbol with a dot in a white circle represent the polarization direction of each light. That is, the double-pointed arrow symbol represents the polarization in the left-right direction in the figure, and the symbol with a dot in the white circle represents the polarization in the direction perpendicular to the drawing sheet.
[0173]
The P-polarized light 651 transmitted through the polarization separation surface 615a is emitted from the polarization conversion element 615 as it is. The S-polarized light 652 reflected by the polarization separation surface 615a is totally reflected by the total reflection surface 615b and then converted to P-polarized light by passing through the λ / 2 wavelength plate 615c. It is injected.
[0174]
Therefore, the light beam 650 incident on the polarization conversion element 615 is all converted into P-polarized light and emitted.
[0175]
FIG. 27 shows a schematic configuration of the polarization conversion element 625 partially enlarged. Similar to the polarization conversion element 615, the polarization conversion element 625 also includes a polarization separation surface 625a and a total reflection surface 625b coated with a dielectric multilayer film that separates P-polarized light and S-polarized light, and a λ / 2 wavelength plate 625c. Although it is configured, the installation position of the λ / 2 wavelength plate 625c is different from that of the polarization conversion element 615. The light beam 660 that has passed through the lens array plates 623 and 624 and entered the polarization conversion element 625 is separated by the polarization separation surface 625a into two linearly polarized light components that are orthogonal to each other. That is, in the light beam 660, the P-polarized light 661 passes through the polarization separation surface 625a, and the S-polarized light 662 is reflected by the polarization separation surface 625a. The P-polarized light 661 that has passed through the polarization separation surface 625a passes through the λ / 2 wavelength plate 625c, is converted to S-polarized light, and is emitted from the polarization conversion element 625. Further, the S-polarized light 662 reflected by the polarization separation surface 625a is totally reflected by the total reflection surface 625b and is emitted from the polarization conversion element 625 as it is.
[0176]
Accordingly, the light beam 660 incident on the polarization conversion element 625 is all converted into S-polarized light and emitted.
[0177]
Returning to FIG. 25 again, the light emitted from the light source 610 and converted to P-polarized light by the polarization conversion element 615 and the light emitted from the light source 620 and converted to S-polarized light by the polarization conversion element 625 are both supplied to the polarization beam splitter 630. Incident.
[0178]
The P-polarized light from the light source 610 passes through the polarization beam splitter 630 as it is, and the S-polarized light from the light source 620 is reflected by the polarization beam splitter 630 and both exit the polarization beam splitter 630. Thereafter, the light is reflected by the mirror 631 and is incident on the DMD 632 that is an object to be illuminated at a predetermined angle.
[0179]
Therefore, the DMD 632 is illuminated with both the light from the light source 610 and the light from the light source 620. In the present embodiment, the illumination light that illuminates the DMD 632 is designed to enter the DMD 632 approximately telecentricly so that the multiplexing efficiency in the polarization beam splitter 630 does not decrease.
[0180]
The DMD 632 is supplied with modulation data representing an image by a control unit (not shown), and light carrying the image reflected by the DMD 632 is attached to the outer surface of the rotating drum 637 via the collimator lens 635 and the focusing lens 636. The recorded recording medium 638 is exposed to record an image.
[0181]
The rotating drum 637 has a cylindrical shape and rotates at a predetermined speed around its central axis. FIG. 25 shows a state in which the rotary drum 637 is viewed from the direction of the rotation axis, and the rotation axis extends in a direction perpendicular to the drawing sheet. An illumination optical system 601 including the DMD 632 and the lenses 635 and 636 is movable along the rotation axis in a direction perpendicular to the drawing sheet. The illumination optical system 601 performs main scanning in the rotation direction of the rotating drum 637 and sub-scanning in a direction parallel to the rotation axis substantially orthogonal to the rotating drum 637 to two-dimensionally scan and expose the recording medium 638 to record an image. To do.
[0182]
The recording medium 638 is not particularly limited, and a photosensitive material, a film, a PS plate, or the like is used.
[0183]
In the illumination optical system 601 in the above embodiment, two lens array plates are used as an integrator illumination optical system, but one lens array plate may be used. In addition, a polarization conversion element is provided behind the pair of lens array plates (with respect to the light source) (for example, a polarization conversion element 615 is installed behind the lens array plates 613 and 614). A polarization conversion element may be provided. Further, the polarization conversion element may be provided in the very vicinity of the lens array plate (for example, the polarization conversion element 615 is provided immediately behind the lens array plate 614 in FIG. 24).
[0184]
Next, another example of the lamp light source used in the present invention will be described with reference to FIG. This light source combines light from three lamps, and generally shows the principle of combining light from n light sources.
[0185]
As shown in the drawing, the illumination optical system 670 including the lamp light source has three light sources 680, 690, and 700 that emit non-polarized light. In the figure, the blocks denoted by reference numerals 682, 692, 696, and 702 all represent combinations of integrator optical systems and polarization conversion elements. For example, the pair of lens array plates 613 and 614 and the polarization in FIG. This is an optical system comprising a combination of a conversion element 615 and lenses 616 and 617. Reference numerals 694 and 704 are polarization beam splitters that combine two lights.
[0186]
In this configuration, first, light from the light source 680 is converted to, for example, P-polarized light by the optical system 682, and light from the light source 690 is converted to, for example, S-polarized light by the optical system 692, as described in the configuration of FIG. These two polarized lights are combined by a polarization beam splitter 694.
[0187]
This polarization combined light is again converted into, for example, P-polarized light by the optical system 696, while the light from the light source 700 is converted to, for example, S-polarized light by the optical system 702, and these two lights are converted into the same as above. The light is combined by a polarization beam splitter 704 and emitted.
[0188]
In this way, the amount of light can be increased by repeating polarization multiplexing regardless of the number of light sources, and n-fold multiplexing is generally possible. Also, by combining the illumination light in this way, it is possible to increase the amount of light even with a low wattage light source, and since two or more light sources are used, one light source cannot be used for some reason Even in such a case, the amount of light is reduced, but the device can be used continuously.
[0189]
Next, an image exposure apparatus which is another embodiment of the present invention will be described with reference to FIG. An image exposure apparatus 710 (hereinafter referred to as an exposure apparatus 710) shown in FIG. 29 uses a conventional PS plate normally used in the printing plate making field as the photosensitive material P, and this is imagewise exposed to form an image. This is so-called UV-CTP (Computer to Plate) recording a (latent image). This CTP performs editing work using a personal computer (PC) or the like, generates (digital) image data of each created page, and exposes the PS plate with recording light modulated in accordance with the image data. Thus, plate making is directly performed from a PC or the like to the PS plate.
[0190]
The exposure apparatus 710 basically includes a light source unit 712, an integrator unit 714, a wavelength selection unit 716, a light amount adjustment unit 718, a digital micro device 720 (hereinafter referred to as DMD 720) that is a spatial light modulation element, The imaging optical system 722, the drum 724, the drive control means (not shown) of the exposure apparatus 710, and the like are configured.
[0191]
As will be described in detail later, the exposure apparatus 710 in the illustrated example is a drum scanner using an outer drum (outer drum), and the photosensitive material P is wound / held on the side surface of the drum 724 while rotating the drum 724. The photosensitive material P is two-dimensionally exposed by light carrying an image modulated by the DMD 720 by relatively moving the optical system and the drum 724 in the axial direction of the drum 724.
[0192]
In the exposure apparatus 710, the light source unit 712 includes a discharge lamp 726 and a reflector 728 that collects the light emitted from the discharge lamp 726 and reflects the light in a predetermined direction.
[0193]
As the discharge lamp 726 as a lamp light source, various discharge lamps such as a xenon lamp, a mercury lamp, and a high-pressure mercury lamp can be used as long as the light corresponding to the spectral sensitivity characteristic of the photosensitive material P can be emitted with a sufficient amount of light. However, preferably, an ultra-high pressure discharge lamp and a metal halide lamp are used.
[0194]
The ultra high pressure discharge lamp specifically has a mercury vapor pressure of 8 × 10 at the time of lighting. ⁶ A discharge lamp having a pressure of Pa (about 80 atm) or more, more preferably a distance between electrodes of 2.5 mm or less. Such ultra high pressure discharge lamps are disclosed in, for example, Japanese Patent Nos. 2829339, 2980882, JP-A-6-52830, JP-A-11-111226, JP-A-11-176385, and JP-A-2000-294199. It is disclosed.
[0195]
Since such an ultra-high pressure discharge lamp is a so-called short arc type with a short inter-electrode distance (arc length), it is close to a point light source and can efficiently illuminate even a spatial light modulator such as DMD720 having a small light receiving surface. Compared with a normal high-pressure mercury lamp or the like, the light utilization efficiency can be greatly improved. Moreover, since the mercury vapor pressure is high, in addition to the emission spectrum of mercury such as i-line, h-line, and g-line, a continuous spectrum is emitted over a wide wavelength range. The material P exposure time can be shortened to improve productivity. A metal halide lamp is also preferable in the same point.
[0196]
The integrator unit 714 is for uniformly irradiating the DMD 720 with light emitted from the light source unit 712 with no unevenness, and includes a first lens array plate 730, a second lens array plate 732, and a first field lens. 734 and a second field lens 736.
[0197]
The first lens array plate 730 and the second lens array plate 732 are fly-eye lenses in which a large number of small lenses are arranged. The first lens array plate 730 spatially divides the light from the discharge lamp 726 and condenses it on the second lens array plate 732. In addition, the second lens array plate 732 forms the individual fly array lens images of the first lens array plate 730 on the DMD 720 via the first field lens 734 and the second field lens 736 (Kohler illumination). Further, the first field lens 734 and the second field lens 736 synthesize the individual fly array lens images on the DMD 720.
[0198]
By having such an integrator unit 714, the light from the discharge lamp 726 can be illuminated on the DMD 720 by making it rectangular and uniform.
[0199]
The light that has passed through the integrator unit 714 then enters the wavelength selection unit 716. The wavelength selection unit 716 is a wavelength selection mirror that reflects light in a wavelength region that matches the spectral sensitivity characteristic of the photosensitive material P to a predetermined optical path and transmits light in other wavelength regions (unnecessary light). In this way, unnecessary light is prevented from entering the subsequent (downstream) optical system. The exposure apparatus 710 of the illustrated example uses, as an example, a conventional PS plate having spectral sensitivity for light having a wavelength of 350 nm to 450 nm (hereinafter simply referred to as ultraviolet light) as the photosensitive material P. Ultraviolet light is reflected on the optical path, and other unnecessary light is transmitted.
[0200]
As described above, the discharge lamp, in particular, the ultra-high pressure discharge lamp and the metal halide lamp suitably used in the exposure apparatus 710 of the present invention emit light having a wide range of wavelengths. Further, the exposure apparatus 710 used for UV-CTP or the like is optimally designed in accordance with the spectral sensitivity characteristics of the photosensitive material P, and if unnecessary light is present, it may be adversely affected by the heat generated by the optical member.
[0201]
On the other hand, in the exposure apparatus 710 of the present embodiment, by disposing the wavelength selecting unit 716, unnecessary light is removed here, and unnecessary light is emitted to the DMD 720, the imaging optical system 722, the photosensitive material P, and the like. It is possible to perform exposure of a suitable photosensitive material P that prevents incidence and eliminates adverse effects caused by the incident.
[0202]
There are no particular limitations on the wavelength selection means 716, and various types can be used as long as they can separate (wavelength selection) light in a necessary wavelength range and other unnecessary light according to the photosensitive material P to be exposed. Means and the like are available. Among these, the wavelength selection means using the dielectric multilayer film is preferably used in that damage due to heat generation due to light absorption can be suitably prevented.
[0203]
In the illustrated example, a wavelength selection mirror that reflects the necessary light is used, but conversely, a transmission type wavelength selection that transmits ultraviolet light through a predetermined optical path and reflects unnecessary light out of the optical path. It may be a filter.
[0204]
Further, the installation position of the wavelength selection unit 716 is not particularly limited, and may be appropriately determined according to the configuration of the optical system, the wavelength selection unit to be used, and the like. It arrange | positions upstream (light source side) rather than a modulation element.
[0205]
In this exposure apparatus 710, an absorbing unit 738 that absorbs and dissipates unnecessary light is disposed on the back side of the wavelength selection unit 716 that is the destination of the separated unnecessary light. Thereby, the bad influence by unnecessary light can be prevented more suitably, and it is preferable.
[0206]
As the absorbing means 738, various types of devices can be used as long as they can absorb unnecessary light reliably and can radiate heat generated by light absorption appropriately. As an example, a combination of a blackboard that absorbs light and a fan that radiates fins and cooling air that contacts the blackboard is exemplified.
[0207]
The ultraviolet light reflected by the wavelength selecting unit 716 is then incident on the light amount adjusting unit 718 to adjust the light amount. The light amount adjusting means 718 in this example includes a turret 740, a rotation drive source 742, a selection unit 744, and a mirror 746.
[0208]
The turret 740 is a circular turret having eight light quantity adjustment mirrors 748 (748a to 748h) as conceptually shown in FIG.
[0209]
The rotational drive source 742 rotates the turret 740 by rotating the central shaft 740a. In the exposure apparatus 710 of the illustrated example, the selected single light amount adjustment mirror 748 is inserted into the optical path of the ultraviolet light from the wavelength selection means 716 by the rotation of the turret 740.
[0210]
The light quantity adjustment mirrors 748 are mirrors having different reflectivities of ultraviolet light. For example, the light quantity adjustment mirror 748a has the lowest reflectance, and the reflectance gradually increases toward the light quantity adjustment mirror 748h. Therefore, by selecting the light amount adjustment mirror 748 inserted in the optical path, the reflected light amount of ultraviolet light, that is, the light amount of ultraviolet light incident on the DMD 720 can be adjusted.
[0211]
Note that an absorption unit 750 similar to the above-described absorption unit 738 is disposed as a preferable mode in the travel destination of the ultraviolet light that is transmitted without being reflected by the light amount adjustment mirror 748.
[0212]
The light source used in this exposure apparatus 710 that is UV-CTP is a discharge lamp, in particular, an ultra-high pressure discharge lamp, in terms of the irradiation efficiency of the spatial modulation element and the amount of ultraviolet light necessary for exposure of the conventional PS plate. A metal halide lamp or the like is preferable. On the other hand, these discharge lamps cannot adjust the amount of light with the light source. Instead, the image data processing also serves as the adjustment of the amount of light. There are problems such as taking time and effort.
[0213]
On the other hand, in this embodiment, the light amount of the light for exposing the photosensitive material P is adjusted by the light amount adjusting means. Therefore, the adjustment range of the light amount can be greatly expanded, and the photosensitive material P can be exposed with an appropriate light amount with a simple configuration and operation. In addition, since the burden of light amount adjustment for image data processing can be greatly reduced, the amount of correction of image data can be reduced, and the burden and cost of the control unit of the DMD 720 can be greatly reduced.
[0214]
In exposure apparatus 710 of the present embodiment, there is no particular limitation on the light amount adjusting means, and various devices can be used as long as they can adjust the light amount of light in a necessary wavelength region (ultraviolet light in the illustrated example). is there. Further, the present invention is not limited to a mirror that uses reflected light, but may be a transmissive so-called ND filter that adjusts the amount of light by transmitting light in a necessary wavelength range.
[0215]
In particular, mirrors and filters that use dielectric multilayer films are preferably used. The dielectric multilayer film has little light absorption, and can prevent damage due to heat and adverse effects on other members. Therefore, it is particularly suitable for UV-CTP or the like that preferably uses a light source with a high light quantity such as an ultra-high pressure discharge lamp or a metal halide lamp. A mirror or filter using a dielectric multilayer film can be prepared in the same manner as a known dichroic mirror (dichroic filter) or the like.
[0216]
The number of light quantity adjustment mirrors 748, that is, the number of stages of light quantity adjustment is not particularly limited, and the characteristics of the photosensitive material P, the light quantity of the discharge lamp 726 and the assumed light quantity fluctuation, and the performance of the developing device that processes the photosensitive material P, etc. It may be determined as appropriate according to the stability, the gradation resolution of the DMD 720, etc. (correction ability with respect to the light amount fluctuation of the light source), and the like.
[0217]
Naturally, as the number of light quantity adjustment mirrors 748 increases, a wider light quantity range can be dealt with, fine light quantity adjustment can be performed, and the burden of processing image data can be reduced. . However, the more light quantity adjustment mirrors 748, the more disadvantageous in terms of cost. According to the study by the present inventor, in consideration of such points, in order to ensure a sufficient adjustment range and adjustment resolution, the number of light quantity adjustment mirrors 748 is preferably about 5 to 10.
[0218]
Selection of the light amount adjustment mirror 748 inserted in the optical path of the ultraviolet light and control of rotation driving of the rotation drive source 742 are performed by the selection unit 744 according to the result of light amount measurement of the discharge lamp 726.
[0219]
As described above, the light amount adjusting means 718 has the mirror 746. The mirror 746 is configured to be insertable / retractable by a known means in the ultraviolet light path between the imaging optical system 722 and the drum 724. The selection unit 744 includes a light amount sensor that measures ultraviolet light reflected by the mirror 746 inserted in the optical path. Further, in the selection unit 744, the relationship between the light amount of ultraviolet light measured by the light amount sensor and the light amount adjustment mirror 748 to be used is set in a table, for example.
[0220]
When selecting the light quantity adjustment mirror 748 to be inserted into the optical path, for example, after confirming that the discharge lamp 726 is stable depending on the lighting time, the DMD 720 is modulated into a predetermined state (for example, all pixels (mirrors) are turned on). ) And a mirror 746 is inserted into the optical path.
[0221]
The ultraviolet light reflected by the mirror 746 is measured by the light amount sensor of the selection unit 744. The selection unit 744 selects the light amount adjustment mirror 748 to be used from the light amount of the ultraviolet light using the above-described table, and drives the rotation drive source 742 to rotate the turret 740 according to the selected light amount adjustment mirror. A mirror 748 is inserted in the optical path of the ultraviolet light.
[0222]
Such a light amount adjustment mirror 748 is selected when, for example, the optical member such as the discharge lamp 726 or the mirror is changed, the lot of the photosensitive material P is changed, or when the exposure apparatus 710 is started, every time an image is recorded. The timing may be set as appropriate.
[0223]
Further, the light quantity adjustment mirror 748 to be used corresponds to an input from the outside in accordance with the result of image recording (when the photosensitive material P is a conventional PS plate as in the illustrated example, the state of the obtained printed matter). Of course, it may be configured to be switchable according to an instruction or the like.
[0224]
The light quantity measurement of the discharge lamp 726 is not limited to the above method, and various methods can be used. For example, the drum 724 can be moved and a light amount sensor that can be moved to the recording position can be installed to measure the light amount, or the optical system can be changed by using the movement of the optical system unit described later. The light quantity may be measured by moving in the axial direction to a predetermined position and arranging a light quantity sensor at this position.
[0225]
The arrangement position of the light amount adjustment mirror 748 constituting the light amount adjustment unit 718 is not particularly limited, and may be determined as appropriate according to the configuration of the optical system and the light amount adjustment unit 718. Thus, it is preferable to be upstream of DMD720. Further, in the case where the wavelength selection unit 716 is provided, it is preferable to dispose the light selection mirror 748 downstream from the viewpoint of easiness of designing each light amount adjustment mirror 748 and light amount accuracy.
[0226]
Further, the switching of the light amount adjustment mirror 748 is not limited to the configuration using the turret 740 as shown in the illustrated example. For example, a method using a slide plate that holds a plurality of light amount adjustment mirrors in a straight line, individual light amount adjustment mirrors Various methods such as a method of providing an insertion / retraction means for the optical path can be used.
[0227]
In the illustrated example, the wavelength selecting unit 716 and the light amount adjusting mirror 748 for adjusting the light amount are separately provided, but the present invention is not limited to this, and the light amount adjusting unit (or wavelength selecting unit) is configured to select the wavelength. You may give two functions of light quantity adjustment.
[0228]
However, in the exposure apparatus 710 and the like, a plurality of folding mirrors are usually inserted for the purpose of downsizing the apparatus (optical system), and a filter having two functions of wavelength selection and light amount adjustment with high accuracy. Is difficult to design and expensive. Therefore, in consideration of design, apparatus cost, accuracy, and the like, it is advantageous that the wavelength selecting unit and the light amount adjusting unit are separate members as in the illustrated example.
[0229]
The ultraviolet light, which is reflected by the light amount adjusting mirror 748 of the light amount adjusting means 718 and adjusted in light amount, is reflected in a predetermined direction by the optical path adjusting mirror 752 and enters the incident surface of the DMD 720 at a predetermined angle.
[0230]
As is well known, the DMD 720 is formed by arranging a large number of micromirrors (on / off) individually oscillated (on / off) at a predetermined angle (for example, 1280 pixels × 1024 pixels in the case of SXGA). By being modulated and driven according to the recorded image, each micromirror is individually oscillated to reflect / modulate the incident light and emit it as projection light carrying the image.
[0231]
The spatial light modulation element is not limited to the DMD 720 in the illustrated example, and various spatial light modulation elements such as a liquid crystal shutter array can be used. Further, the spatial modulation element may be one-dimensional.
[0232]
The light amount adjustment by the light amount adjusting means 718 described above is stepwise, so that the modulation by the DMD 720 may have the function of adjusting the light amount of ultraviolet light by correcting the image data that drives the DMD 720 as necessary. Good.
[0233]
In the exposure apparatus 710 of the present embodiment, since the light amount adjustment means 718 previously adjusts the light amount of ultraviolet light, the amount of calculation is larger than that of a conventional device even if image data is corrected. And the burden on the control unit and image data processing unit of the DMD 720 can be greatly reduced.
[0234]
The projection light carrying the image modulated by the DMD 720 is imaged at a predetermined image recording position by the imaging optical system 722. The photosensitive material P is held by the drum 724 at this image recording position.
[0235]
The imaging optical system 722 is a known imaging optical system that is formed by combining a plurality of lenses.
[0236]
The drum 724 is a cylinder that rotates with the photosensitive material P wound around the outer surface during image recording. The axis of the drum 724 is aligned with the pixel (micromirror) arrangement direction of the DMD 720 so that the surface of the held photosensitive material P is the image recording position. In one direction, the rotation direction is optically aligned with the other direction of the pixel arrangement direction.
[0237]
In the illustrated example, the optical system from the light source unit 712 to the imaging optical system 722 is integrally unitized. The optical system unit is moved in the axial direction of the drum 724 by a known method during image recording (or the drum 724 may be moved in the axial direction while rotating).
[0238]
As described above, the exposure apparatus 710 in the illustrated example is a so-called drum scanner, and the rotation of the drum 724 (main scanning) and the movement of the optical system unit in the axial direction (sub scanning) The entire surface of the photosensitive material P held on the drum 724 is irradiated two-dimensionally by projection light of the DMD 720 that moves relative to the drum 724 and carries the image, and the image is exposed and recorded.
[0239]
Such image recording may be performed by a known method using a spatial light modulator and a drum scanner. Specifically, as in the image recording disclosed in US Pat. No. 5,049,901 and European Patent No. 0992350A1, the DMD 720 is synchronized with the rotation of the drum 724 (moving speed of the photosensitive material P). The image to be formed is optically shifted (moved) in the same direction so that the image follows / stills on the photosensitive material P, and the image is exposed. Image exposure can be performed on the entire surface of the photosensitive material P by performing this image exposure together with the two-dimensional relative movement of the optical system and the drum 724 described above.
[0240]
Alternatively, an optical deflector is disposed between the DMD 720 and the imaging optical system 722, and the projection light from the DMD 720 is deflected in this rotational direction in synchronization with the rotation of the drum, so that the projection light from the DMD 720 is deflected. The image may be recorded by following the rotated photosensitive material P and stopping the image of one screen of the DMD 720 at a fixed position on the photosensitive material P for a predetermined recording time (exposure time). By performing this image recording together with the above-described two-dimensional relative movement between the optical system and the drum 724, one screen image of the DMD 720 is two-dimensionally arranged on the photosensitive material P, and the entire surface of the photosensitive material P is recorded. It is possible to perform image recording.
[0241]
This image recording method is described in detail in Japanese Patent Application Nos. 2000-316622 and 2001-116470 by the present applicant.
[0242]
Note that the image exposure apparatus 710 in the illustrated example is a drum scanner that uses a so-called outer drum, but the exposure apparatus of the present invention is not limited to this, and may be a combination of a discharge lamp and a spatial light modulation element. For example, a so-called inner drum that holds the photosensitive material on the inner surface of the cylinder may be used, or two-dimensional exposure is performed by holding the photosensitive material in a planar shape and moving relative to the optical system. A so-called flat bed may be used.
[0243]
In addition, the exposure apparatus 710 in the illustrated example includes both the wavelength selection unit and the light amount adjustment unit as a preferred mode, but is not limited thereto, and may include only one of them.
[0244]
Next, with reference to FIG. 31, an exposure apparatus according to still another embodiment of the present invention will be described. The image exposure apparatus 810 (hereinafter referred to as an exposure apparatus 810) shown in FIG. 31 is light having a wavelength of 350 nm to 450 nm (hereinafter referred to as ultraviolet light) that is normally used in the printing plate making field as the photosensitive material P. ) Is a so-called UV-CTP in which a PS plate having spectral sensitivity characteristics (hereinafter referred to as a conventional PS plate) is used and imagewise exposed to record an image (latent image).
[0245]
Such an exposure apparatus 810 basically includes a light source unit 812, an integrator unit 814, an optical path changing mirror 816 (816a, 816b, 816c), and a digital micromirror device 818 (hereinafter referred to as a spatial light modulator). DMD 818), imaging optical system 820, drum 822, drive control means (not shown) of exposure apparatus 810, and the like.
[0246]
As will be described in detail later, the exposure apparatus 810 in the illustrated example is a drum scanner using an outer drum (outer drum), and the photosensitive material P is wound / held on the side surface of the drum 822 and the drum 822 is rotated. The photosensitive material P is two-dimensionally exposed by projection light carrying an image modulated by the DMD 818 by relatively moving the optical system and the drum 822 in the axial direction of the drum 822.
[0247]
In the present invention, the target photosensitive material P is not particularly limited, but in the present invention in which a short arc ultra-high pressure discharge lamp described later is used as a light source, exposure can be performed with a high amount of ultraviolet light. Therefore, the conventional PS plate as shown in the example, which requires a high amount of ultraviolet light to perform efficient exposure, is particularly preferably used.
[0248]
In the exposure apparatus 810, the light source unit 812 includes a light source 828 including two lamps 824 (824 a and 824 b), reflectors 826 (826 a and 826 b) corresponding to the lamps 824, and a monitor that monitors the state of both lamps 824. Part 830.
[0249]
In this apparatus, a short arc ultra-high pressure discharge lamp is used as the lamp 824 serving as an exposure light source.
[0250]
A short arc ultra-high pressure discharge lamp is a lamp having a shorter distance (arc length) between electrodes than a normal high-pressure mercury lamp or the like, and a pressure higher than the mercury vapor pressure during lighting. Preferably, the mercury vapor pressure during lighting is 8 × 10 ⁶ A lamp satisfying at least one of Pa (about 80 atmospheres) or more and a distance between electrodes of 2.5 mm or less, more preferably satisfying both. Regarding such a short arc ultra-high pressure discharge lamp, Japanese Patent Nos. 2829339, 2980882, JP-A-6-52830, JP-A-11-111226, JP-A-11-176385, JP-A-2000-294199, etc. Is described in detail.
[0251]
Such a short arc ultra-high pressure discharge lamp is mainly used for a visible light application such as a projector. However, according to the study by the present inventors, this lamp is close to a point light source because the distance between the electrodes is short. Even a spatial light modulator having a small light receiving surface such as DMD818 can be illuminated efficiently. Moreover, since the mercury vapor pressure is high, in addition to the emission spectrum of mercury such as i-line, h-line, and g-line, a continuous spectrum is emitted over a wide wavelength range, corresponding to the spectral sensitivity characteristics of the conventional PS plate. Ultraviolet light is emitted with a high amount of light.
[0252]
That is, this short arc ultra-high pressure mercury lamp is optimal as an exposure light source for a photosensitive material that requires a high amount of ultraviolet rays in order to perform efficient exposure as in the conventional PS plate. The exposure apparatus 810 uses a short arc type ultra-high pressure discharge lamp, uses a high amount of ultraviolet light with high utilization efficiency, that is, increases the amount of exposure light, shortens the exposure time of the conventional PS plate, and improves productivity. Good UV-CTP is realized.
[0253]
Although the exposure apparatus 810 in the illustrated example uses two lamps 824, the number is not limited to this, and the number of the lamps 824 may be one or three or more, and the ultraviolet light emitted from the lamps 824 may be used. What is necessary is just to select suitably the number which can obtain sufficient light quantity according to the light quantity of light, required productivity (exposure time), the sensitivity of the photosensitive material P, etc.
[0254]
In the light source unit 812, such a lamp 824 is turned on when the exposure apparatus 810 is activated, and basically the operation of the apparatus is performed except when a special instruction such as turning off for lamp replacement is issued. Lights up to the end.
[0255]
Here, as a preferred mode, the exposure apparatus 810 in the illustrated example shows the total lighting time for each of the lamps 824a and 824b and the lighting state (whether lighting or non-lighting) for each of the lamps 824a and 824b. It has a monitor unit 830 that monitors and outputs various warnings, lamp replacement instructions, etc., and extinguishes the lamp 824 in accordance with the results. Note that the lighting time and lighting state of the lamp 824 may be monitored by a publicly known method performed by various optical devices.
[0256]
As described above, the short arc ultra-high pressure discharge lamp used as the lamp 824 in the present invention is optimal as a UV-CTP exposure light source, but on the other hand, it is generally easy to rupture and further has a total lighting time of some time. It has a feature that the probability of bursting increases when the time exceeds (depending on the lamp type).
[0257]
On the other hand, the exposure apparatus 810 in the illustrated example monitors the total lighting time and lighting state of the individual lamps 824, and performs a lamp replacement warning or a forced lamp turn-off process accordingly. Thereby, the rupture of the lamp 824 is suitably prevented to ensure sufficient safety, and even when the lamp 824 is not lit due to failure or rupture, the state can be quickly grasped and promptly Thus, a stable operation of the exposure apparatus 10 is realized by enabling processing such as simple replacement.
[0258]
Hereinafter, the monitor unit 830 will be described in more detail with reference to the flowchart of FIG.
[0259]
Although the exposure apparatus 810 in the illustrated example has two lamps 824a and 824b, in FIG. 32, only the flow corresponding to one lamp 824 (for example, lamp 824a) is monitored for the total lighting time. Indicates. However, with respect to the other lamp 824, the total lighting time is monitored according to the completely same flow (the flow from “power ON” to “message display” toward the lower side in FIG. 32). Needless to say.
[0260]
In the illustrated example, as a preferred mode, both the total lighting time and the lighting state are monitored, but only one of them may be monitored.
[0261]
In the exposure apparatus 810, the lamp 824 is turned on when the apparatus is activated (power is turned on). However, in the state in which the lamp 824 is turned on, the monitor unit 830 always operates the lamp 824a and the lamp 824b. The total lighting time (total lighting time since the exposure apparatus 810 is mounted) is monitored and checked.
[0262]
The monitor unit 830 is set with a first predetermined time and a second predetermined time for preventing the lamp 824 from bursting and ensuring the safety of the exposure apparatus 810. The first predetermined time and the second predetermined time may be appropriately determined according to the specification of the lamp 824 to be mounted, the guaranteed lighting time, and the like. In the illustrated example, as an example, 1500 hours (1500 h) is set as the first predetermined time, and 2000 hours (2000 h) is set as the second predetermined time.
[0263]
The monitor unit 830 checks the total lighting time of each lamp 824. As a result, if the total lighting time is less than 1500 hours (N), the lamp 824 is turned on (continues lighting or starts lighting).
[0264]
On the other hand, for the lamp 824 having a total lighting time of 1500 hours or more (Y), it is further checked whether or not the total lighting time is 2000 hours or more.
[0265]
When the total lighting time is less than 2000 hours (N) as a result of the check, the monitor unit 830 outputs a message indicating that the total lighting time of the corresponding lamp 824 has exceeded 1500 hours, and the lamp 824. Set to ON.
[0266]
The content of the message at this time is not particularly limited, and examples include a report that the total lighting time of the lamp 824 has exceeded 1500 hours, a warning that the lamp 824 is near the end of its life, a content that prompts early replacement, and the like. The In the example shown in the figure, the message “Lamp No. x is about to end its life. Replace it as soon as possible. When the lamp reaches the end of its life, it cannot be lit and cannot be made.” Is output.
[0267]
There is no particular limitation on the message output method, and various output methods are possible. For example, display on a display provided in the exposure apparatus 810, audio output, output of a hard copy in which a message is recorded, a combination of two or more of these, and the like are exemplified. In this regard, other messages are the same.
[0268]
On the other hand, when the total lighting time of the lamp 824 is 2000 hours or more, the monitor unit 830 forcibly turns off the lamp 824 and outputs a message indicating that the replacement of the lamp 824 is instructed.
[0269]
The content of the message when the total lighting time of the lamp 824 is 2000 hours or more is not particularly limited, a warning that the lamp is at the end of its life, an instruction to replace the lamp 824, a warning that the lamp 824 cannot be turned on, etc. Is exemplified. In the example shown in the figure, if the total lighting time of the lamp 824 is 2000 hours or more, “No.x lamp is at the end of its life. The lamp cannot be turned on. Replace the lamp immediately. Message is output.
[0270]
On the other hand, as described above, when the total lighting time of the lamp 824 is less than 2000 hours, the corresponding lamp 824 is turned on. However, in the state where the lamp 824 is lit, the monitor unit 830 has each lamp. Apart from the total lighting time for each 824, the lighting state (lit or unlit) is monitored and checked for each lamp 824 at all times.
[0271]
As a result of checking the lighting state of each lamp 824 by the monitor unit 830, if all the lamps 824 are lit (Y), it is confirmed whether or not the exposure device 810 is being exposed (image recording of the photosensitive material P). The As a result, if the exposure is in progress (Y), the exposure is continued. If the exposure is not in progress (N), an exposure standby state (waiting for an exposure instruction) is entered.
[0272]
On the other hand, as a result of the monitor unit 830 confirming the lighting state of each lamp 824, even when there is a non-lighted lamp 824 (N), it is similarly confirmed whether or not the exposure apparatus 810 is performing exposure and exposure ( If Y), the exposure is interrupted.
[0273]
If there is a non-lighted lamp 824, whether it is during exposure (Y) or not during exposure (N), the monitor unit 830 turns off the non-lighted lamp 824, and this A message indicating that the lamp 824 is not lit is output. Note that the exposure apparatus 810 is configured to allow exposure by slowing down the exposure speed (that is, increasing the exposure time) even if there is a non-lighted lamp 824, as a preferred mode. .
[0274]
The content of the message is not particularly limited, and examples include a warning that there is a non-lighted lamp, the number of the non-lighted lamp 824, an instruction to replace the non-lighted lamp 824, and a warning that the exposure time is delayed. Is done. In the example shown in the figure, if there is a lamp 824 that is not lit, “No.x lamp is not lit. Replace the lamp immediately. The message “It will be longer” is output.
[0275]
The light emitted from the light source unit 812 (the light source 828) enters the integrator unit 814. The integrator unit 814 irradiates the DMD 818 with light emitted from the light source 828 uniformly and efficiently, and includes a first lens array plate 838, a second lens array plate 840, and a first field lens 842. , And a second field lens 844.
[0276]
The first lens array plate 838 and the second lens array plate 840 are fly-eye lenses in which a large number of small lenses are arranged. The first lens array plate 838 spatially divides the light from the lamp 824 and condenses it on the second lens array plate 840. The second lens array plate 840 images each fly array lens image of the first lens array plate 838 on the DMD 818 via the first field lens 842 and the second field lens 844 (Kohler illumination). Further, the first field lens 842 and the second field lens 844 combine the individual fly array lens images on the DMD 818.
[0277]
By having such an integrator unit 814, the light from the lamp 824 can be illuminated on the DMD 818 by making it rectangular and uniform.
[0278]
The light that has passed through the integrator unit 814 is then reflected by the optical path changing mirrors 816a, 816b, and 816c, and is incident on the light receiving surface of the DMD 818, which is a spatial light modulator, at a predetermined angle.
[0279]
In order to remove light unnecessary for exposure, one of the three mirrors 816 reflects only ultraviolet light corresponding to the spectral sensitivity characteristic of the photosensitive material P to a predetermined optical path, and emits light of other wavelengths ( It is preferably a wavelength selective mirror that transmits unnecessary light).
[0280]
The DMD 818 is a two-dimensional array of micromirrors that individually swing (on / off) at a predetermined angle (for example, 1280 pixels × 1024 pixels in the case of SXGA). By being modulated and driven according to the image, each micromirror is individually oscillated, and the incident light is reflected / modulated and emitted as projection light carrying the image.
[0281]
Note that the frequency of modulation by the DMD 818 depends on the number of unlit lamps 824 when exposure is performed despite the fact that the unlit lamp 824 is confirmed by the monitor unit 830 of the light source unit 812. Reduced.
[0282]
The spatial light modulation element is not limited to the DMD 818 in the illustrated example, and various spatial light modulation elements such as a liquid crystal shutter array can be used.
[0283]
The projection light carrying the image modulated by the DMD 818 is imaged at a predetermined image recording position by the imaging optical system 820. Further, the photosensitive material P is held by the drum 822 at this image recording position.
[0284]
The imaging optical system 820 is a known imaging optical system that is formed by combining a plurality of lenses. The drum 822 is a cylinder that rotates with the photosensitive material P wound around the outer surface during image recording. The axis of the drum 822 is aligned with the pixel (micromirror) arrangement direction of the DMD 18 so that the surface of the held photosensitive material P is the image recording position. In one direction, the rotation direction is optically aligned with the other direction of the pixel arrangement direction.
[0285]
In the illustrated example, the optical system from the light source 828 to the imaging optical system 820 is integrally unitized. The optical system unit is moved in the axial direction of the drum 822 by a known method during image recording (or the drum 822 may move in the axial direction while rotating).
[0286]
As described above, the exposure apparatus 810 in the illustrated example is a so-called drum scanner, and the rotation of the drum 822 (main scanning) and the movement of the optical system unit in the axial direction (sub scanning) The photosensitive material P held on the drum 822 is irradiated two-dimensionally with the projection light of the DMD 818 that carries the image relative to the drum 822 and carries the image, and the image is recorded on the entire surface.
[0287]
Note that, although it is confirmed by the monitor unit 830 of the light source unit 812 that there is an unlit lamp 824, the rotation speed of the drum 822 is equal to the number of unlit lamps 824 when exposure is performed. In response, it is lowered.
[0288]
In this apparatus, such image recording may be performed by a known method using a spatial light modulation element and a drum scanner. As the specific method, the method mentioned in the description of the apparatus shown in FIG. 29 can be similarly applied.
[0289]
Next, still another embodiment of the exposure apparatus of the present invention will be described with reference to FIG. The image exposure apparatus 910 schematically shown in FIG. 33 uses a DMD (digital micromirror device) that is a two-dimensional spatial light modulator and a so-called external drum (outer drum) to scan a photosensitive material two-dimensionally. An exposure apparatus, which basically includes a light source unit 912, a uniform irradiation optical system 914, a collimator lens 916, a movable mirror shutter (rotatable reflection mirror) 918, a DMD 920, and an imaging optical system 922. , An external drum 924 (hereinafter simply referred to as a drum 924) and a sub-scanning drive system (not shown).
[0290]
The lamp light source unit 912 emits illumination light that exposes the photosensitive material wound around the outer surface of the drum 924, and includes a lamp 926 and a reflector 928.
[0291]
As the lamp 926, various lamps corresponding to the spectral sensitivity of the target photosensitive material can be used as long as a sufficient amount of light can be emitted. For example, if the photosensitive material is a commonly used PS plate that can be exposed to ultraviolet rays (conventional PS plate), an ultraviolet lamp such as an ultra-high pressure mercury lamp or a metal halide lamp may be used.
[0292]
The reflector 928 includes a lamp 926 and is a spheroid having an inner surface serving as a light reflecting layer, reflects the illumination light emitted from the lamp 926 and condenses it at the focal position.
[0293]
The light emitted from the light source unit 912 then enters the uniform irradiation optical system 914. The uniform irradiation optical system 914 makes the light (light quantity distribution) incident on the DMD 920 uniform in the surface direction of the DMD 920 (two-dimensional pixel array direction). And an eye lens 932.
[0294]
The uniform irradiation optical system 914 is arranged immediately downstream of the light condensing position by the reflector 928 (downstream in the light traveling direction), and the illumination light emitted from the light source unit 912 is converted into parallel light by the collimator lens 930 and then rectangular. By diffusing with the fly-eye lens 932 having a shape, the light incident on the DMD 920 is made into a rectangle corresponding to the pixel array of the DMD 920 and has a uniform light amount distribution.
[0295]
The irradiation light diffused by the uniform irradiation optical system 914 is converted into parallel light by the collimator lens 916, and then reflected by the movable mirror shutter 918 in a predetermined direction during image exposure, and the reflected light enters the DMD 920.
[0296]
The movable mirror shutter 918 is rotatable between a position indicated by reference numeral 918a and a position indicated by reference numeral 918b. During normal image exposure, the movable mirror shutter 918 is at the position indicated by reference numeral 918a. When the rotation angle of the micromirror in the DMD 920 is ± θ, the incident angle to the DMD 920 (horizontal position micromirror) is 2θ. Thus, the parallel light is reflected. For example, if the rotation angle of the micromirror is ± 10 °, the movable mirror shutter 918 reflects the illumination light from the light source unit 912 that is parallel light so that the incident angle to the DMD 920 is 20 °.
[0297]
The movable mirror shutter 918 is rotated to a position indicated by reference numeral 918b during non-image exposure, and the illumination light is reflected so as not to enter the DMD 920, which will be described later.
[0298]
The DMD 920 is a two-dimensional spatial light modulator in which rectangular micromirrors capable of rotating (swinging) a predetermined angle around a predetermined rotation axis are two-dimensionally arranged, and electrostatically rotate the micromirror. Thus, the light is modulated by turning on / off the exposure for each micromirror (= pixel). Such a DMD 20 is formed on a silicon chip by a micromachine technology applying a semiconductor device manufacturing process.
[0299]
For example, as described above, if the rotation angle of the micromirror is ± 10 °, if the exposure is on, the rotation angle of the micromirror is + 10 °, and the incident light at the incident angle of 20 ° is DMD 920 (at the horizontal position). The light is reflected in the normal direction of the micromirror) and enters the drum 924 through the imaging optical system 922 as light that carries the image, and forms an image. On the other hand, if the exposure is off, the rotation angle of the micromirror is −10 °, and the light incident at an incident angle of 20 ° is the DMD 920 (horizontal position micromirror) method, as indicated by the dashed arrow in the figure. The light is reflected at an angle of 40 ° with respect to the line direction and does not enter the imaging optical system 922.
[0300]
In the illustrated exposure apparatus 910, as an example, a DMD 920 having a pixel interval of 17 μm and 1280 pixels × 1024 pixels is used.
[0301]
Further, the rotation direction of the drum 924 and the pixel row direction of the 1024 pixels of the DMD 920 optically coincide (this direction is referred to as the main scanning direction), and the axial direction of the drum 924 and the pixel row direction of the 1280 pixels of the DMD 920 are Each member is arranged so as to optically match (this direction is referred to as a sub-scanning direction).
[0302]
In the present embodiment, the two-dimensional spatial light modulator is not limited to the DMD 920 as shown in the example, and various known two-dimensional spatial light modulators such as a liquid crystal display (LCD) and a ferroelectric liquid crystal. Various spatial light modulation elements can be used. However, among them, DMD is most preferable in terms of high modulation speed and high light utilization efficiency.
[0303]
At the time of image exposure, light carrying an image reflected by the DMD 920 in the normal direction of the (horizontal micromirror) (that is, an image formed by the DMD 920) is reflected by the imaging optical system 922 on the surface of the drum 924 The image is formed on the surface of the photosensitive material held on the surface. The central pixel of the DMD 920 coincides with the optical axis of the imaging optical system 922, and each part is arranged so that this optical axis is orthogonal to the tangent line of the drum 924.
[0304]
The exposure apparatus 910 in the illustrated example exposes an image of 2400 dpi as an example.
Accordingly, since the pixel interval on the exposure surface is 10.58 μm, the imaging optical system 922 forms an image on the drum 924 with the light carrying the image modulated and reflected by the DMD 920 at a magnification of 0.623 times. That is, the maximum exposure area on the exposure surface is 13.5 mm × 10.8 mm.
[0305]
The drum 924 is a cylinder that rotates around an axis with a photosensitive material mounted on the outer surface. In the exposure apparatus 910 of the present embodiment, the system from the light source unit 912 to the imaging optical system 922 is unitized as shown by a dotted line in the drawing (hereinafter referred to as an optical system unit 956). And is configured to move at a predetermined speed in the sub-scanning direction by a known method.
[0306]
The exposure device 910 is a so-called drum scanner, and at the time of exposure of the photosensitive material, the light modulated according to the image to be recorded is incident on the drum 924 (photosensitive material on the outer surface of the drum 924) and rotates the drum 924 while performing sub-scanning. Move the optical system unit 956 in the direction. As a result, the photosensitive material is two-dimensionally scanned and exposed by light carrying an image to record an image, and for example, a conventional PS plate is made.
[0307]
As described above, in this exposure apparatus 910, the exposure area in the sub-scanning direction on the exposure surface is 13.5 mm at the maximum. Move in the scanning direction. In addition, since the DMD 920 has 1280 pixels in the sub-scanning direction, the exposure apparatus 910 can perform multiple exposure of 1280 pixels.
[0308]
In the exposure apparatus 910 of this embodiment, during such exposure, an image (modulation in the DMD 920) formed by the DMD 920 is also scanned (moved) in the main scanning direction in synchronization with the rotation (main scanning) of the drum 924. Multiple exposure is performed. That is, when the drum 924 rotates by one pixel (for 10.58 μm), the image formed by the DMD 920 also moves in the main scanning direction by one pixel. Accordingly, in the illustrated example, 1024 multiple exposures are performed at the maximum.
[0309]
By performing such multiple exposure, the light use efficiency can be increased and the photosensitive material can be exposed with a sufficient amount of light. For example, a conventional PS using a general ultraviolet lamp such as an ultra-high pressure mercury lamp can be used. It is possible to perform plate making by exposing the plate. Alternatively, in the case of recording a gradation image, a gradation image having a target resolution can be recorded by fully utilizing the number of pixels in the main scanning direction. In particular, the DMD 920 as shown in the illustrated example has a higher light utilization efficiency than an LCD or the like, and therefore more suitable image exposure is possible.
[0310]
By the way, in this image exposure apparatus 910, once the light source unit 912 is turned off, it takes time until the light quantity stabilizes when the light source unit 912 is turned on again. Therefore, the light source unit is always turned on regardless of whether the image exposure is on or off. The light 912 is turned on and is continuously irradiated with illumination light to the DMD 920. Therefore, the DMD 920 continues to be irradiated with illumination light, particularly near-ultraviolet light, so that there is a problem that the failure frequency increases and the lifetime of the two-dimensional spatial light modulator is shortened.
[0311]
In view of this, the image exposure apparatus 910 includes an optical system that prevents illumination light from irradiating the two-dimensional spatial light modulator during non-image exposure. That is, in the present embodiment, normally, the reflecting mirror that reflects the illumination light from the light source unit 912 toward the DMD 920 can be rotated as the movable mirror shutter 918, the reflection direction of the illumination light is changed, and non-image exposure is performed. The illumination light is prevented from entering the DMD 920.
[0312]
The movable mirror shutter 918 is synchronized with the image recording control on the photosensitive material, and is reflected so that the illumination light is incident on the DMD 920 indicated by reference numeral 918a, and the illumination light is not incident on the DMD 920 indicated by reference numeral 918b. It rotates between the reflecting positions.
[0313]
At the time of non-image exposure, the movable mirror shutter 918 is raised to the position of reference numeral 918b to reflect illumination light near the light source unit 912 so that the reflected light does not enter the DMD 920.
[0314]
At this time, it is preferable to provide a light absorbing plate 934 near the light source unit 912, return the illumination light toward the light absorbing portion 912, and further radiate the light power absorbed by the light absorbing plate 934 with a heat sink or the like. .
[0315]
As described above, since the DMD 920 is not irradiated with illumination light (near-ultraviolet light) at the time of non-image exposure, it is not necessary to turn off the light source unit 912. The lifetime of the modulation element can be improved.
[0316]
The optical system that prevents the illumination light from irradiating the two-dimensional spatial light modulation element during non-image exposure is not limited to the movable mirror shutter 918 described above, and the illumination light is not incident on the DMD 920. Various things can be used as long as they do.
[0317]
For example, the movable mirror shutter 918 used in the above embodiment may be a normal fixed reflecting mirror 918, and another reflecting mirror may be inserted only at the time of non-image exposure at the position of reference numeral 918b in the drawing. That is, at the time of image exposure, the illumination light is reflected at a predetermined angle by the reflection mirror 918 toward the DMD 920, and at the time of non-image exposure, a reflection mirror different from the reflection mirror 918 is inserted at a position indicated by reference numeral 918b. The light is reflected toward the light absorbing plate 934.
[0318]
Alternatively, the movable mirror shutter 918 is a normal fixed reflecting mirror 918, and a shutter (light shielding plate) is inserted in place of the reflecting mirror at the position of reference numeral 918b to block the light so that the illumination light does not enter the DMD 920. It may be. Alternatively, a so-called shutter may be provided at a position denoted by reference numeral 918b so that the shutter is opened during image exposure, and the shutter is closed during non-image exposure so as to block illumination light.
[0319]
Thus, when the illumination light is blocked by the shutter, the light absorbing plate 934 is not necessary.
[0320]
The image exposure apparatus described above records images on a photosensitive material by multiple exposure using a two-dimensional spatial light modulation element. The method for exposing an image is such a multiple exposure method. While not limited, the image to be imaged on the recording medium is moved while being synchronized with the movement of the step-and-repeat exposure method or the drum, and the image is relatively stationary on the recording medium. Of course, a so-called following scanning exposure method in which image exposure is performed may be used.
[0321]
Further, the present invention is not limited to the discharge lamp, and the present invention can also be suitably used when a light source that takes a long time to be stabilized after being turned on, such as a halogen lamp.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the appearance of an exposure apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a scanner used in the exposure apparatus of FIG.
FIG. 3A is a plan view showing an exposed region formed on a photosensitive material, and FIG. 3B is a diagram showing an arrangement of exposure areas by each exposure head.
4 is a perspective view showing a schematic configuration of an exposure head in the exposure apparatus of FIG. 1. FIG.
5 is a sectional view in the sub-scanning direction along the optical axis showing the configuration of the exposure head shown in FIG.
FIG. 6 is a partially enlarged view of a digital micromirror device (DMD).
FIG. 7 is an explanatory diagram for explaining the operation of the DMD.
FIG. 8 is an explanatory diagram showing a comparison of exposure beam arrangement and scanning lines when DMD is not arranged in an inclined manner (A) and in an inclined arrangement (B).
FIG. 9 is a side view showing an example of a conventional exposure head.
FIG. 10 is an explanatory diagram showing an example of a DMD usage area;
FIG. 11 is a schematic diagram for explaining an exposure method for exposing a photosensitive material by one scanning by a scanner.
FIG. 12 is a schematic diagram for explaining an exposure method for exposing a photosensitive material by a plurality of scans by a scanner.
FIG. 13A is a plan view showing a light image projected on an exposed surface when a microlens array or the like is not used, and a light image projected on the exposed surface when a microlens array or the like is used. Plan view (B)
FIG. 14 is a schematic configuration diagram showing another example of a lamp light source used in the present invention.
15 is a schematic configuration diagram showing a polarization conversion element used in the lamp light source of FIG.
16 is a schematic configuration diagram showing another polarization conversion element used in the lamp light source of FIG.
17 is an explanatory diagram showing a configuration of a second lens array plate used in the lamp light source of FIG.
FIG. 18 is an explanatory diagram showing a configuration in which the first and second lens array plates and the polarization conversion element are integrated.
FIG. 19 is a schematic configuration diagram showing still another example of a lamp light source used in the present invention.
FIG. 20 is a schematic configuration diagram showing still another example of a lamp light source used in the present invention.
FIG. 21 is a schematic configuration diagram (a) showing an image exposure apparatus according to another embodiment of the present invention, and a schematic diagram (b) showing a part thereof;
FIG. 22 is an explanatory diagram for explaining an example of an illumination optical system in the image exposure apparatus of FIG.
FIG. 23 is an explanatory diagram for explaining an example of the arrangement of lens optical systems in the image exposure apparatus of FIG.
FIG. 24 is an explanatory diagram for explaining the action of light when a total reflection prism is applied to the image exposure apparatus in FIG.
FIG. 25 is a schematic block diagram showing an image exposure apparatus according to still another embodiment of the present invention.
26 is a schematic block diagram showing a polarization conversion element used in the image exposure apparatus of FIG.
27 is a schematic block diagram showing another polarization conversion element used in the image exposure apparatus of FIG. 25. FIG.
FIG. 28 is a block diagram showing still another lamp light source used in the present invention.
FIG. 29 is a schematic block diagram showing an image exposure apparatus according to still another embodiment of the present invention.
30 is a conceptual diagram of a turret of a light amount adjusting unit arranged in the image exposure apparatus shown in FIG. 29.
FIG. 31 is a schematic block diagram showing an image exposure apparatus according to still another embodiment of the present invention.
FIG. 32 is a flowchart for explaining lamp monitoring in the image exposure apparatus shown in FIG. 31;
FIG. 33 is a schematic block diagram showing an image exposure apparatus according to still another embodiment of the present invention.
[Explanation of symbols]
50 Digital Micromirror Device (DMD)
52, 54, 57, 58 Lens of imaging optical system
55 Micro lens array
56 Surface to be exposed
59 Aperture Array
66 Mercury lamp
67 Irradiation lens system
71 Collimator lens
72,73 Micro Fly Eye Lens
74 Field lens
150 Photosensitive material
152 stages
162 Scanner
166 Exposure head
168 Exposure area
170 Exposed area
210, 220, 230, 240 Light source
250, 260, 270 Polarizing beam splitter
212, 222, 232, 242, 252, 282 An optical system comprising a first lens array plate, a polarization conversion element, and a second lens array plate
320 First light source
321,331 lamp
322, 332 reflector
324, 334 First lens array plate
326,336 Polarization conversion element
326a, 336a Polarization separation surface
326b, 336b Total reflection surface
326c, 336c λ / 2 wave plate
328, 338 Second lens array plate
330 Second light source
340 Polarizing beam splitter (polarizing element)
340a Polarization separation surface
510 Illumination light source
510a lamp
512 Digital micromirror device
514 Collimator lens optical system
516 Optical deflector
518 Focusing lens optical system
520 Sub-scanning drive system
522 External drum
524 recording medium
530 lens group
540, 541 interface
542 Total reflection prism
543,544 Normal
546,547 separation line
610, 620 Light source
611,612 lamp
612,622 Reflector
613,623 First lens array plate
614, 624 Second lens array plate
615,625 Polarization conversion element
615a, 625a Polarization separation surface
615b, 625b Total reflection surface
615c, 625c λ / 2 wave plate
616,617,626,627 lenses
630 Polarizing beam splitter
631 Mirror
632 DMD
636 Focusing Lens
637 Rotating drum
638 recording medium
680, 690, 700 Lamp light source
682, 692, 696, 702 (including polarization conversion element) optical system
694,704 Polarizing beam splitter
710 exposure equipment
712 Light source
714 Integrator
716 Wavelength selection means
718 Light intensity adjusting means
720 DMD (Digital Micromirror Device)
722 Imaging optical system
724 drums
726 Discharge lamp
728 reflector
730 First lens array plate
732 Second lens array plate
734 1st field lens
736 Second field lens
738,750 Absorbing means
740 Turret
742 Rotation drive source
744 selection part
746,752 Mirror
748 (748a-748h) Light quantity adjustment mirror
810 (Image) exposure apparatus
812 Light source
814 Integrator
816 (816a, 816b, 816c) mirror
818 DMD (Digital Micromirror Device)
820 Imaging optical system
822 drums
824 (824a, 824b) lamp
826 (826a, 826b) reflector
828 Light source
830 monitor section
838 First lens array plate
840 Second lens array plate
842 First field lens
844 2nd field lens
910 Image exposure apparatus
912 Light source
914 Uniform illumination system
916,930 collimator lens
918 Movable mirror shutter
918a, 918b The position where the movable mirror shutter rotates
920 DMD (Digital Micromirror Device)
922 Imaging optical system
924 (external) drum
926 lamp
928 reflector
932 Fly Eye Lens
934 light absorption plate
956 Optical system unit

Claims (5)

An exposure head that is moved in a direction crossing a predetermined direction with respect to the exposure surface,
A plurality of spatial light modulation elements in which a large number of pixel units that modulate the irradiated light according to control signals are arranged two-dimensionally;
A plurality of lamp light sources provided one by one for each of these spatial light modulation elements;
An irradiation optical system for irradiating the spatial light modulation element with light emitted from the lamp light source;
An exposure head comprising an imaging optical system that forms an image carried by the light spatially modulated by the plurality of spatial light modulation elements on the exposure surface. 2. The exposure head according to claim 1, further comprising control means for controlling each of the plurality of pixel portions less than the total number of the pixel portions based on a control signal generated according to exposure information. The pixel unit controlled by the control unit is a pixel unit included in a region in which a length in a direction corresponding to the predetermined direction is longer than a length in a direction intersecting the predetermined direction. Exposure head. A light quantity distribution correcting optical system for correcting the light quantity distribution of the light emitted from the lamp light source so as to be substantially uniform on the spatial light modulation element is provided between the lamp light source and the spatial light modulation element. The exposure head according to any one of claims 1 to 3, wherein the exposure head is characterized in that: An exposure head according to any one of claims 1 to 4,
An exposure apparatus comprising: moving means for moving the exposure head relative to the exposure surface in a direction crossing a predetermined direction.

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