KR20150120981A - Exposure optics, exposure head, and exposure device - Google Patents

Abstract

An exposure optical system, an exposure head and an exposure apparatus provided with a microlens array for correcting aberration of an imaging optical system are provided. A spatial light modulation element 34 in which a pixel portion 74 for modulating light B from a light source is arranged and a microlens 64a for condensing light modulated in the spatial light modulation element 34 are arranged on a plane A first imaging optical system 52 for imaging the light B modulated by the spatial light modulation element 34 onto the microlens array 64, And a second imaging optical system 58 for imaging the condensed light B on the photosensitive material P in the array 64. The microlens array 64 is arranged on the optical axis of the second imaging optical system 58, And a plurality of kinds of microlenses 64a having different shapes are arranged according to the distance from the light source 58c.

Description

EXPOSURE OPTICS, EXPOSURE HEAD, AND EXPOSURE DEVICE [0002]

The present invention relates to an exposure optical system, an exposure head, and an exposure apparatus.

There is known an image exposure apparatus having an exposure head and exposing a desired pattern onto a photosensitive material by the exposure head. An exposure head of this type of image exposure apparatus basically comprises a light source, a spatial light modulation element in which a plurality of pixel sections for independently modulating the light irradiated from the light source are independently modulated, And an imaging optical system for imaging the image by the light modulated by the light source on the photosensitive material.

(Hereinafter referred to as " DMD ") as a light modulation device having a light source and a plurality of micromirrors as an example of the configuration of the exposure head of the image exposure apparatus, and a micro- There is shown a configuration including a microlens array in which a plurality of microlenses for individually condensing a plurality of beam bundles are arranged (see, for example, Patent Document 1).

With such a configuration using the microlens array, even if the size of the image exposed on the photosensitive material is enlarged, the bundle of rays from each pixel portion of the spatial light modulation element is condensed by each microlens of the microlens array, The pixel size (= spot size of each ray) of the exposed image in the exposure image is compressed and kept small so that sharpness of the image can be maintained at a high level.

The exposure head shown in Japanese Unexamined Patent Application Publication No. 2007-33973 further includes an imaging optical system on the emission side of the microlens array and a light beam from each pixel portion of the spatial light modulation element on the surface (exposure surface) The bundle is focused as a spot.

However, in the image exposure apparatus, all aberrations of the imaging optical system formed on the emission side of the microlens array have an influence on the shape of the spot on the photosensitive surface, which causes the focus to deteriorate due to expansion or deformation of the spot.

In the example described in Japanese Patent Application Laid-Open No. 2007-33973, the influence of off-axis aberration of a remarkable imaging optical system on the spot shape can not be avoided.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an exposure optical system, an exposure head and an exposure apparatus provided with a microlens array for correcting aberration of an imaging optical system in consideration of the above facts.

According to a first aspect of the present invention, there is provided a spatial light modulation device comprising: a spatial light modulation device in which pixel portions for modulating light from a light source are arranged; a micro lens array in which microlenses for condensing light modulated by the spatial light modulation device are arranged on a plane; A first imaging optical system for imaging the light modulated by the spatial light modulation element on the microlens array and a second imaging optical system for imaging the light condensed on the microlens array on the photosensitive material, The array includes a plurality of kinds of microlenses different in shape according to the distance from the optical axis of the second imaging optical system.

According to the present invention, the aberration existing in the exposure optical system can be corrected by the microlens array in which microlenses having different shapes are arranged. In this configuration, since the off-axis aberration of the imaging optical system is corrected by changing the shape of the microlens itself at a distance from the optical axis without inserting any correction optical system into the optical path, the performance (brightness, contrast, etc.) of the entire exposure optical system is not deteriorated, Can be corrected.

The second embodiment of the present invention is characterized in that the polar coordinates indicating the coordinates in the second imaging optical system are represented by ρL2, φL2, the Zernike standard function is Zi (ρ, φ), the Zernike standard coefficient of the i-th term of the second imaging optical system is Δi A parameter representing coordinates on the surface of the microlens is denoted by r, phiML, a maximum radius of the aperture of the microlens is denoted by rmax, The refractive index of the material of the microlens array is denoted by n, and the Zernike standard function is denoted by Zi (r / rmax,?). Is a surface shape described by Equations 2 and 3 (described later) for correcting the aberration of the second imaging optical system.

According to the present invention, the off-axis aberration existing in the second imaging optical system is corrected by the microlens array in which a plurality of types of microlenses having different shapes are arranged according to the distance from the optical axis of the second imaging optical system, Off-axis aberration correction can be performed.

In the third embodiment of the present invention, the above-mentioned formula 3 is satisfied with respect to a part of i in which the microlens array satisfies i? 4 and? M (i) = 0 is satisfied with respect to other i.

According to the present invention, the shape of the beam spot on the surface of the photosensitive material can be maintained by specifically selecting and correcting the fourth order or higher order aberration which loses the symmetry of the beam such as the astigmatism and the third order coma aberration.

A fourth embodiment of the present invention includes the exposure optical system described in any one of the first to third embodiments.

According to the present invention, the aberration existing in the exposure optical system can be corrected in the microlens array by arranging a plurality of types of microlenses having different shapes. In this configuration, since the off-axis aberration is corrected by changing the shape of the microlens itself at the distance from the optical axis without inserting a certain correction optical system into the optical path, the aberration can be corrected without deteriorating the performance of the exposure optical system.

A fifth embodiment of the present invention includes the exposure head described in the fourth embodiment of the present invention.

According to the present invention, the aberration existing in the exposure optical system can be corrected in the microlens array by arranging a plurality of types of microlenses having different shapes. In this configuration, since the off-axis aberration is corrected by changing the shape of the microlens itself at the distance from the optical axis without inserting a certain correction optical system into the optical path, the aberration can be corrected without deteriorating the performance of the exposure optical system.

(Effects of the Invention)

Since the present invention has the above-described structure, an exposure optical system, an exposure head, and an exposure apparatus each having a microlens array for correcting the aberration of the imaging optical system can be used.

1 is a perspective view showing a main part of an exposure apparatus according to an embodiment of the present invention.
2 is a perspective view showing a main part of an exposure head according to an embodiment of the present invention.
3 is a perspective view showing an example of the structure of a DMD used in an optical system according to an embodiment of the present invention.
4A is a perspective view showing the ON state of the DMD used in the embodiment of the present invention.
4B is a perspective view showing an off state of the DMD used in the embodiment of the present invention.
5 is a conceptual diagram showing the arrangement of optical elements after the DMD of the optical system according to the embodiment of the present invention.
6 is a conceptual diagram showing an arrangement of a plurality of kinds of microlenses with respect to a second imaging optical system optical axis of the microlens array used in the optical system according to the embodiment of the present invention.
7A is a graph showing the relationship between the position of the beam spot PB on the photosensitive material P in the microlens, the second imaging optical system, and the photosensitive material P when the beam modulated by the micromirror of the optical system according to the embodiment of the present invention is imaged as the beam spot PB. And the position of the beam in each coordinate system.
7B is a view showing the distance (radial direction) and the radial direction from the optical axis in the plane shape of the microlens.
7C is a diagram showing the polar coordinates on the surface of the microlenses.
7D is a coordinate system showing aberrations in the second imaging optical system.
8A is a check showing the definition of the Zernike standard coefficient.
FIG. 8B is an example of a standard Zernike polynomial using FIG. 8A.
9 is a conceptual diagram showing a change in beam spot shape caused by an increase or decrease in a higher order aberration with respect to a distance from a second imaging optical system optical axis of a microlens array used in an optical system according to an embodiment of the present invention.
10 is a conceptual diagram showing a surface shape of a microlens according to an embodiment of the present invention. 10A is a surface shape for correcting aberration at an image position (distance) of 70% from the optical axis to the imaging range.
FIG. 10B shows a surface shape for correcting the aberration at the image position (distance) 100%, that is, the imaging range limit.
Fig. 11 is a graph showing the relationship between the distance (radial direction) and the radial direction from the optical axis in the plane shape of the microlens according to the embodiment of the present invention and the coordinate system described in the radial direction and the coordinate system FIG.
Fig. 12 is a conceptual diagram showing an object position in a conventional optical system and an influence of the off-axis aberration of the imaging optical system on the spot shape.
13A is a comparison chart of aberration coefficient values (arbitrary units) before and after correction on an image plane at an image position (image height) of 70% according to an embodiment of the present invention.
13B is a comparison chart of aberration coefficient values (arbitrary units) before and after correction on the image plane at an image position (image height) of 100% according to the embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

<Overall configuration>

As shown in Figs. 1 and 2, the exposure apparatus 10 including the exposure optical system 100 according to the present embodiment includes a flat plate-like moving stage 14 . Two guides 20 extending along the stage moving direction are provided on the upper surface of a plate-shaped mounting table 18 supported by a plurality of (for example, four) leg portions 16. The movable stage 14 is arranged such that its longitudinal direction is directed toward the stage moving direction and is supported so as to be reciprocally movable along the guide 20. [ The exposure apparatus 10 is also provided with a stage driving device (not shown) for driving the moving stage 14 as the sub scanning means along the guide 20.

At the center of the mounting table 18, a gate 22 of an overbridge shape is provided so as to extend over the moving path of the moving stage 14. [ Each of the ends of the gate 22 is fixed to both sides of the mount 18. A scanner 24 is provided on one side with the gate 22 therebetween and a plurality of sensors 26 are provided on the other side to detect the leading edge and trailing edge of the photosensitive material P . The scanner 24 and the sensor 26 are respectively attached to the gate 22 and fixedly disposed upstream of the movement path of the moving stage 14. [ The scanner 24 and the sensor 26 are connected to a controller (not shown) for controlling them.

The scanner 24 includes a plurality (14 in the figure) of exposure heads 28 arranged in a substantially matrix shape of m rows and n columns, for example. The exposure area 30 by each exposure head 28 is a rectangular shape with the short side in the sub scanning direction. Accordingly, the exposure completed area 31 is formed in the photosensitive material P in the form of a strip for each exposure head 28 as the moving stage 14 moves.

The plurality of exposure heads 28 are formed by, for example, a light source (not shown) emitting a laser beam having a wavelength of 400 nm (for example, a semiconductor laser LD) For example, a DMD 34 shown in Fig. 3 as a spatial light modulation device modulating every pixel portion. The DMD 34 is connected to a controller (not shown) having a data processing section and a mirror drive control section. The data processing section of the controller generates a control signal for driving and controlling each of the micromirrors 74 (described later) in the use area on the DMD 34 for each of the exposure heads 28 based on the inputted image data. The mirror drive control unit controls the angle of the reflecting surface of each micromirror 74 of the DMD 34 for each exposure head 28 based on the control signal generated by the image data processing unit.

5 shows the optical system after the DMD 34 in a conceptual view. A main optical system for imaging the laser beam B reflected by the DMD 34 onto the photosensitive material P is disposed on the light reflecting side (emitting side and irradiation side) of the DMD 34. [ The main optical system includes a first imaging optical system 52 for magnifying a beam modulated by the DMD 34, a second imaging optical system 58 for imaging a beam on the photosensitive material P, A first aperture array 66 disposed near the exit side of the microlens array 64 and a second aperture array 68 disposed at the focal point of the microlens array 64 ).

The first imaging optical system 52 is composed of, for example, an incident-side lens 52A and an emergent-side lens 52B, and the DMD 34 is disposed on the focal plane of the lens 52A. The lens 52A and the lens 52B have the same focal plane and the microlens array 64 is disposed on the focal plane on the exit side of the lens 52B. The second imaging optical system 58 also includes a lens 58A on the incident side and a lens 58B on the exit side and the lenses 58A and 58B have the same focal plane, The focal position of the microlens array 64 in which the two aperture arrays 68 are disposed is the focal plane of the lens 58A. And the photosensitive material P is disposed on the focal plane on the exit side of the lens 58B.

The first imaging optical system 52 expands the image by the DMD 34 and forms an image on the microlens array 64. Further, the second imaging optical system 58 projects an image formed by the microlens array 64 onto the photosensitive material P to form an image. The first imaging optical system 52 and the second imaging optical system 58 all emit a plurality of bundles of rays from the DMD 34 as a bundle of rays substantially parallel to each other.

As shown in Fig. 3, the DMD 34 used in the present embodiment has a plurality of (for example, 1024 x 768) smiles constituting pixels (pixels) on an SRAM cell (memory cell) And mirror (micro mirror 74) are arranged in a lattice shape. For each pixel, a rectangular micro-mirror 74 supported by a support is provided at the uppermost portion, and a material having a high reflectivity such as aluminum is deposited on the surface of the micro-mirror 74.

When a digital signal is inputted to the SRAM cell 72 of the DMD 34, each of the micromirrors 74 supported on the support is tilted at any one of +/- 占 with respect to the substrate side on which the DMD 34 is disposed, Loses. FIG. 4A shows a state in which the micromirror 74 is in an on state and + a ° in an on state, and FIG. 4B shows a state in which the micromirror 74 is in an off state -?. Therefore, by controlling the inclination of the micromirror 74 in each pixel of the DMD 34 in accordance with the image signal as shown in Figs. 4A and 4B, the laser light B incident on the DMD 34 is reflected by the respective And is reflected in the oblique direction of the micromirror 74.

4A and 4B show an example of a state in which a part (one micromirror portion) of the DMD 34 is enlarged and the micromirror 74 is controlled at +? Degrees or-? Degrees. The ON / OFF control of each of the micromirrors 74 is performed by a controller (not shown) connected to the DMD 34. [

<Micro Lens Array>

The microlens array 64 has a plurality of microlenses 64a corresponding to the respective micromirrors 74 on the DMD 34 arranged in a two-dimensional shape of, for example, about 1024 x 768. In this embodiment, a flat steel lens formed of quartz glass is used. Each microlens 64a has a surface shape that corrects the aberration of the second imaging optical system as described later.

Further, the present invention is not limited to the above example, and a tin lens or the like may be used as a basic form. The microlenses 64a may be formed integrally with the connection portions connecting the microlenses 64a in the form of an array by using the same material or may be a microlens array 64 or a plurality of openings The micro lenses 64a may be sandwiched between the base openings. Further, a two-layer microlens array having lens power may be superimposed to form a microlens array 64. [

An aperture array 68 in which a plurality of openings corresponding to the respective microlenses 64a are formed is provided on the emission side of the microlens array 64. [

The aperture array 68 may be a mask in which a chrome mask (light shielding film made of chrome) is formed at a portion other than the opening on the exit side of the microlens 64a or a mask made of a permeable / semi-permeable coating, A light shielding film may be formed on a transparent mask plate in the vicinity of the exit surface without being brought into contact with the lens 64a.

<Shape and arrangement of microlenses>

The beam (laser beam B) that has passed through the microlens array 64 as described above is imaged as the beam spot PB on the photosensitive material P by the second imaging optical system 58. [ At this time, there is a possibility that the off-axis aberration existing in the second imaging optical system 58 deforms the shape of the beam spot PB as shown in Fig. 12, thereby enlarging the spot diameter and not obtaining a desired resolution.

That is, when the object 164a of the same shape is simply arranged at a position different from the optical axis 58C as shown in Fig. 12, the aberration (off-axis aberration) of the second imaging optical system 58 is shifted PB), and the shape of the beam spot PB (beam spot PB) may be deformed away from the optical axis 58C of the second imaging optical system 58. [ Thereby, there is a possibility that a desired resolution can not be obtained on the image plane.

Therefore, in the present embodiment, the shape of the microlens 64a constituting the microlens array 64 shown in Fig. 5 is changed according to the distance from the optical axis 58C of the second imaging optical system 58, Off-axis aberration of the zoom lens 58 is corrected. This prevents deformation of the shape of the beam spot PB formed on the photosensitive material P and suppresses enlargement of the beam spot PB, thereby enhancing the resolution of the peripheral portion of the image.

Specifically, for example, as shown in Fig. 6, the microlens array 64 is formed of three types of microlenses 64a to 64c having different shapes. The microlens 64 is selected from the three kinds of microlenses 64a1 to 64a3 in accordance with the distance from the optical axis 58C of the second imaging optical system 58 and is optically coupled to the optical axis 58C of the second imaging optical system 58 And are arranged with a predetermined directionality. That is, as described later, the microlenses 64a2 and 64a3 are aspherical lenses, and since the shape of the microlenses 64a2 and 64a3 is also directional, it is necessary to dispose the microlenses 64a2 and 64a3 in a predetermined direction toward the optical axis 58. [

In the example of Fig. 6, a microlens 64a1 (spherical surface) which is not subjected to surface shaping for off-axis aberration correction is used in the immediate vicinity of the optical axis 58C. Next, microlenses 64a2 and 64a3 having a planar shape for off-axis aberration correction are arranged radially in accordance with the distance from the optical axis 58C to constitute a microlens array 64. [

It is assumed that the beam B passing through a certain microlens 64a in the optical system shown in Fig. 7A is imaged as the beam spot PB on the photosensitive material P by the second imaging optical system 58. Fig. 7B, when the distance from the optical axis 58C is? ML, and the coordinate orthogonal to the optical axis 58C is? ML, the microlens 64a has a circular shape with a diameter rMAX, The polar coordinates on the plane of the surface 64a can be described by the distance r from the center and the angle phi ML, as shown in Fig. 7C.

Likewise, when describing an aberration in coordinate values of (? L2,? L2) as the coordinate system in the second imaging optical system 58, polar coordinates can be used as? L2 and? L2, as shown in Fig. 7d. Further, when the beam spot PB is formed on the photosensitive material P, the distance from the optical axis 58C of the second imaging optical system 58 is Y_end, and the coordinate orthogonal to this is X_end. have.

As shown in Fig. 11, the coordinate system (xML, eta M) and the coordinate system (X_end, Y_end) on the surface of the photosensitive material P corresponding to each of the microlenses 64a constituting the microlens array 64, Is not constant but is changed. When the entire optical system is viewed from the DMD 34 side, the correspondence of the respective optical systems to the optical axis 58C of the second imaging optical system 58 is such that the? ML axis and the Y_end axis correspond to the long axis direction (the refraction direction from the optical axis 58C) and X_ML and X_end are radial directions orthogonal to the radial direction. For this reason, it is necessary to consider a position equivalent to the beam spot PB at a specific position of the photosensitive material P on the side of the microlens 64a.

The shape of the microlenses 64a will be described based on the above points. The standard Zernike polynomial used to describe the aberration is described as FIG. 8b.

For example, the fourth term represents the deviation of the focal position, but what relates to the shape of the beam spot PB is the fourth term (Z4).

It is assumed that an aberration represented by the following function exists at an image position of the second imaging optical system 58.

(Equation 1)

? I x lambda x Zi (? L2,? L2)

i

? L2,? L2: a parameter indicating the same coordinates of the second imaging optical system 58

Zi (ρ, φ): Zernike standard function

? I: the aberration coefficient of the second imaging optical system 58

(Zernike standard coefficient in the i-th measure, unit: λ: optical wavelength)

When the microlens 64a is a flat lens, the surface shape of the corresponding microlens 64a is changed in order to correct this, and the surface shape of the microlens 64a necessary for correcting the aberration of? (2) in which the second term is added in addition to the shape (the first term, the microlens 64a1).

(Equation 2)

SagZ (r, φ) = (c × r ^ 2) / (1 + √ (1-c ^ 2 × r ^ 2)

             + (? I x?) / (N-1) x Zi (r / rmax,

r,? ML: a parameter indicating coordinates on the surface of the microlens 64a

rmax: the maximum radius of the opening of the microlens 64a

c: curvature before correction of the microlenses 64a

λ: optical wavelength

n: the refractive index of the material of the microlens array 64

Zi (r / rmax, φ): Zernike standard function

The surface shape of each microlens 64a constituting the microlens array 64 is determined in the same manner as described above and the microlens array 64 It is ideal to correct the aberration of the second imaging optical system 58.

When the microlens array 64 is manufactured by optical lithography, it is relatively easy to change the shape of each microlens 64a. In addition, since the shape of the microlens array 64 is not complicated by selectively correcting a port having a low dimension (a small number of i) and a large value of? And a large influence on the photosensitive material, You can expect.

Hereinafter, the surface shape of the microlenses 64a will be described using specific examples. The optical characteristics of the second imaging optical system 58 are variously considered depending on the use. A representative example of the increase / decrease of the Zernike standard coefficient lowering term due to the distance from the optical axis 58C of the beam spot PB formed on the photosensitive material P is shown in Fig. Z5, Z8, and Z10 are zero in principle because of the method of selecting the coordinate axes.

The larger the absolute value of the coefficient value for each term of the Zernike standard coefficient shown in the vertical axis of FIG. 9 is, the larger the aberration is, and the shape of the beam spot PB is collapsed. 9, when the beam spot PB is imaged by the second imaging optical system 58 on the photosensitive material P, the distance from the optical axis 58C to the beam spot PB is calculated for each term of the Zernike standard coefficient The coefficient values of the first and second embodiments are different.

Here, since the asymmetry (deviation from the circle) of the beam spot PB is reluctant depending on the type of the photosensitive material P, it is preferable to preferentially correct the aberrations of Z6, Z7, and Z9 shown in Fig. 9 It is effective to maintain the resolution at the time of exposure. Thereafter, correction is performed on the shape of the microlens 64a for the portion where the absolute value exceeds 0.25 (arbitrary unit, arbitrary unit: denoted by a. U. In the drawing).

In the example shown in Fig. 9, it can be seen that the influence of Z7 and Z9 is large in the vicinity of the image position 70% (distance from the optical axis 58C) and in the vicinity of the image position 100% in the image position except for Z4 (focus shift) . A description will now be given of a method of correcting Z6 and Z9 by the shape of the microlens 64a as a representative example of the image position 70% position and the image position 100% position.

In FIG. 10A, the amount of shift from the spherical surface of the microlens 64a having the surface shape for correcting the Z6 and Z9 aberrations of the portion corresponding to the image position 70% in FIG. 9 is expressed by a percentage. In the drawing, the right side is eta ML away from the optical axis, that is, the left side in the figure is the optical axis 58C side.

The surface shape for correcting Z6 and Z9 is defined by the following formula. When the wavelength used is 400 nm and the refractive index of the material of the microlens array 64 at this wavelength is 1.47, the surface shape is described by the following formula (3).

(Equation 3)

+ 4.5 x 10 ^ -4 x Z6 (r / rmax,? ML) -1.7 x 10 ^ -4 x Z9 (r / rmax,

The correction of the aberrations of Z4 to Z11 when the microlens 64a having such a surface shape is used is shown in Table 1 as a comparison with the spherical surface in Fig.

In FIG. 10B, a deviation from the spherical surface of the microlens 64a having a surface shape for correcting Z6 and Z9 aberrations corresponding to the image position 100% in FIG. 9 is indicated by a percentage. In the drawing, the right side is eta ML away from the optical axis, that is, the left side in the figure is on the optical axis side is the same as that in Fig. 10A.

Z6, and Z9 is defined by the following expression (4).

(Equation 4)

-4.4 × 10 -4 -4 × Z6 (r / rmax, φML) -5.0 × 10 -4 -4 × Z9 (r / rmax, φML)

A correction situation of the aberration of Z4 to Z11 when the microlens 64a having this surface shape is used is shown in Table 2 as a comparison with the spherical surface in Fig.

By disposing the above-mentioned microlenses 64a at the positions of 70% and 100%, respectively, it is possible to satisfactorily correct large aberrations in each position. In the above description, the 70% position of image height and the 100% position of image height are shown in specific examples. However, it is possible to correct the aberrations separately at this position and other positions by similar examination.

In addition, it is not necessary to individually change the shape of the microlenses 64a depending on the required accuracy. The shape of the microlens 64a may be changed stepwise according to the distribution of the aberration of the imaging optical system 2. [ For example, in a region where the number of the imaging optical systems 2 is relatively small, the spherical shape can be maintained. Further, some of the adjacent microlenses 64a may be unified into a shape for correcting typical aberration values of the imaging optical system 2 within a corresponding range.

6 shows an example in which the shape of the microlens 64a is changed to three levels in accordance with the distance from the optical axis of the imaging optical system 2. [ Needless to say, it is possible to carry out correction with high precision by performing surface type classification in detail for each image position. At this time, as shown in Fig. 9, it is necessary to correct the aberration that strongly affects the beam spot shape while confirming the change of the Zernike standard coefficient at each image position, in order to correct the aberration efficiently. In particular, efficient correction can be performed by changing the surface shape of the microlens 64a in the vicinity of the image position where the Zernike standard coefficient fluctuates severely.

<Others>

Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above-described embodiments, but can be carried out in various embodiments within the range not deviating from the gist of the present invention .

For example, in the above embodiment, the configuration of the exposure apparatus for exposing with laser light is described as an example, but the present invention is not limited thereto, and for example, ordinary visible light or ultraviolet light may be used. Or may be applied to various configurations using spot light in addition to the exposure apparatus.

It is preferable to use a center filter having a higher density or a micro-filter close to the optical axis 58C toward the optical axis 58C closer to the optical axis 58C of the second imaging optical system 58 in order to correct a decrease in the peripheral light quantity of the image formed on the photosensitive material P, And measures such as increasing the transmittance density for the lens 64a may be performed.

In the present embodiment, the DMD 34, which is a reflective spatial modulation device, is used. Instead, a transmissive spatial modulation device using, for example, liquid crystal may be used.

The disclosure of Japanese Patent Application No. 2013-033344 is hereby incorporated by reference in its entirety. All publications, patent applications, and technical specifications described in this specification are herein incorporated by reference in their entirety to the same extent as if each individual article, patent application, and technical specification were specifically and individually indicated to be incorporated by reference.

Claims (5)

A spatial light modulation element in which a pixel portion for modulating light from a light source is arranged,
A microlens array in which microlenses for condensing the modulated light in the spatial light modulation device are arranged on a plane;
A first imaging optical system for imaging the light modulated by the spatial light modulation element on the microlens array,
And a second imaging optical system for imaging the light condensed by the microlens array on the photosensitive material,
Wherein the microlens array has a plurality of types of microlenses arranged in different shapes according to a distance from an optical axis of the second imaging optical system. The method according to claim 1,
And the Zernike standard coefficient of the i-th term of the second imaging optical system is DELTA (i), where? L2 is the coordinate of the second imaging optical system,? L2 is the Zernike standard function of the Zernike standard function, When there is an aberration represented by the following formula 1 at an image position of the optical system,
(Equation 1)
?? (i) x? Xi (? L2,? L2)
i
Wherein the shape of the microlens corresponding to the image position is a parameter expressing coordinates on the surface of the microlens so as to correct the aberration of the second imaging optical system by r and? ML, a maximum radius of the aperture of the microlens by rmax, A refractive index of a material of the microlens array is denoted by n, a Zernike standard function is denoted by Zi (r / rmax, phi), and a portion of the microlens is denoted by (2) and (3): &quot; (2) &quot;
(Equation 2)
SagZ (r, ψ) = (c × r2) / (1 + √ (1-c2 × r2))
+? (? M (i) x? / N-1) Zi (r / rmax,
i? 4
(Equation 3)
? M (i) =? (I) (i? 4) 3. The method of claim 2,
The microlens array satisfies the formula (3) with respect to a part of i satisfying i? 4,
(I) = 0 is satisfied for the other i. An exposure head comprising the exposure optical system according to any one of claims 1 to 3. An exposure apparatus comprising the exposure head according to claim 4.

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