JPH07261292A - Photolithography exposure machine - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to provide high-resolution printing using a high-definition color separation film by providing a photolithography exposure machine with improved non-uniformity of illuminance distribution. Even
Make sure that the tint of the finished print is not uneven. [Structure] Light from a light source 2 composed of a short arc type discharge lamp is condensed by a condenser mirror 31 and is made incident on a single rod lens type integrator 34 to make the illuminance distribution uniform, and to disperse the light on the translucent glass plate 4. This light is applied to the set of the plate-making original 101 and the photoconductor film 102 placed on the condenser lens group 35.
Focus and irradiate. The condenser lens group 35 has a function of negatively correcting the image plane distortion of the exposure surface, and the correction amount is adjusted to adjust the degree of reinforcement of the peripheral illuminance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photolithography exposure machine, and more particularly to a photolithography exposure machine which achieves high precision exposure and can be suitably used as a high definition type.

[0002]

2. Description of the Related Art The technique of photoengraving is widely used as a technique for producing a plate required for various types of printing. The printing technology is roughly classified into letterpress printing, intaglio printing, stencil printing, lithographic printing, etc., but in any method, a dedicated plate is required, and in order to manufacture a high-precision plate, the intermediate process The film exposure technique in photolithography has been improved.

FIG. 8 is a side sectional view for explaining the schematic construction of a conventional photolithography exposure machine. The conventional photolithography exposure machine shown in FIG. 8 includes a machine base 1, a light-transmitting glass plate 4 arranged on the upper surface of the machine base 1, and a light-transmitting glass plate 4 arranged in the machine base 1. It is mainly composed of a light source 2 which irradiates light from below. The machine base 1 is a box-shaped member, has an opening in its upper surface, and the translucent glass plate 4 is fitted and arranged in this opening. The light-transmitting glass plate 4 is formed of a material that at least favorably transmits light having a wavelength used for exposure. The plate-making exposure device is provided with a plate-making manuscript 10 as a base of the plate.
This is performed by exposing the photosensitive film 102 with the light of the pattern 1. More specifically, the photosensitive film 102 is superposed on the plate-making original 101, and the set of the plate-making original and the photosensitive film 102 is placed on the translucent glass plate 4 for exposure, and then development is performed. To make a plate.

The light source 2 is arranged near the center of the bottom surface of the machine base 1 and emits light toward the upper transparent glass plate 4. Examples of the shape of the light source 2 include a rod-shaped shape and a spherical shape. Examples of the former include a mercury lamp and a metal halide lamp, and examples of the latter include an incandescent lamp and a microwave-excited electrodeless lamp. Is mentioned. The metal halide lamp is a general term for a lamp in which a metal and a halogen are sealed, and a lamp in which gallium or iron is sealed as a metal is used as a light source of a photolithography exposure machine. The light emitting parts of these mercury lamps and metal halide lamps have a length of several tens of centimeters (10 to 20 cm).
It is a rod-shaped one. On the other hand, an electrodeless lamp is one in which a luminescent gas enclosed in a spherical envelope is excited by microwaves to emit light, and the size of its light emitting portion is several centimeters (about 3 to 5 cm) in diameter. Is.

In many cases, the conventional photolithography exposure machine is provided with a Fresnel lens 37 below the light-transmitting glass plate 4 for the purpose of collimating the light from the light source 2. This is to prevent misregistration in the peripheral portion when plate making is performed from the large plate making document 101. That is, FIG.
As described above, when the light radially radiated from the light source 2 is used as it is, in the peripheral portion of the plate-making original 101, the image spreads outward and is projected on the photoconductor film 102. In addition, the conventional photolithography exposure machine shown in FIG. 6 includes a cover (not shown) that covers the translucent glass plate 4 on which the set of the platemaking original 101 and the photosensitive film 102 is placed.
The cover is made of a non-translucent material to prevent light leakage during exposure. The cover is made of a flexible material such as rubber, if necessary, and is additionally provided with a vacuum suction mechanism so that the cover comes into close contact with the light-transmitting glass plate 4, whereby the plate-making original 101 and In some cases, the adhesion of the photoconductor film 102 is improved to improve the exposure accuracy.

A plate making operation using such a conventional photolithographic exposure machine is generally performed as follows. First, the plate-making original 101 is produced prior to exposure.
Taking the color printing as an example, the plate-making manuscript 101 is generally
It is composed of a manuscript of a picture part such as a color photograph and a manuscript of a line drawing part composed of characters and figures. Of these, in many cases, a manuscript is created using the technology of a color scanner using a computer for the pattern portion. That is, the case of performing printing by superimposing the three primary colors of Y (yellow) M (red) C (cyan) will be described as an example. First, a design such as a photograph to be printed is read by a scanner, and RGB is read on a computer. After separating into each color of Y, data of each color of YMC corresponding to RGB is created. Then, according to the data of each color, an original of each color of YMC is created as a negative or positive color separation tone film. Specifically, the color data is the hue, lightness, and saturation data of each color, and is represented as the degree of the strength of the three primary colors of YMC when printed. Then, the degree of the strength of the three primary colors is converted into the size of a halftone dot (fine dots are arranged evenly to form a mesh). That is, a pattern of halftone dots corresponding to the color data is drawn on the color separation tone film. For example, R50%, G30%,
In the case of printing a color tone such as overlapping with a combination of B 20% at a specific place, halftone dots having a size of 50% are formed at the place as a plate making document 101 of M and Y plates for reproducing R. The separated color separation film is created, and the G and Y plate reproduction originals 101 for reproducing the G are used as the plate-making originals 101.
A color separation tone film having halftone dots formed thereon is produced, and a color separation tone film having 20% halftone dots formed at the corresponding spots is used as a plate making original 101 for M and C plates for reproducing B. Is created.

A line drawing original such as characters and figures is photographed by a plate making camera and a line drawing film is prepared as a plate making original 101. Further, according to the color tone required for the line drawing, a color-separated film having halftone dots is prepared as in the case of the above-mentioned pattern. The line drawing original is often created separately from the original of the design. When printing a plurality of pictures, line drawings, etc. on one sheet of paper, the color separation film or the like is created for each picture or line drawing. That is, in order to produce one plate, a plurality of plate-making originals 101 are prepared,
The pattern or line drawing of each plate-making original 101 is successively exposed on one photoconductor film 102 to complete one plate. During this sequential exposure, another plate-making original 10
It is general that a mask film is prepared so as not to expose the first portion.

Next, with reference to FIG. 6, the exposure of a set of a plate-making original and a photoconductor film when a conventional photolithographic exposure machine is used will be described. First, the photosensitive film 102 is superposed on the plate-making original 101 prepared as described above, and placed on the light-transmitting glass plate 2. Plate-making manuscript 10
1 and the photoconductor film 102 are positioned so as to have a predetermined positional relationship according to the position of the projected line drawing or pattern.

Then, the translucent glass plate 4 is entirely covered with a cover (not shown), and the light source 2 is turned on in this state. The light from the light source 2 reaches the Fresnel lens 37, becomes parallel light by the Fresnel lens 37, and then enters the translucent glass plate 4. Then, the light passes through the translucent glass plate 4 and reaches the plate-making original 101, and the light passing through the plate-making original 101 is incident on the photoconductor film 102. Similarly, another plate-making original 101 is exposed, and all the plate-making originals 101 are exposed.
When the exposure of 1 is completed, the exposure of one plate is completed. Then, work such as development is performed to complete the plate.

[0010]

In the plate making process described above, the fineness of the halftone dots of the color separation film determines the fineness of the printed matter, that is, the resolution. That is, when the halftone dots are rough, a jagged halftone dot shape is visually recognized on the finished printed matter at the boundary portion where the contour and the hue of the pattern change. Except in the case of newspaper printing etc., such a jagged dot shape is not visible in normal printing,
It is required to use finer dots in terms of higher precision printing. The fineness of the mesh is indicated by the term screen ruling and is represented by the number of points that fall within one inch. For example, if there are 150 points in 1 inch, they are expressed as 150 lines / inch, but they are abbreviated as 150 lines. The larger the number of screen lines, the finer the halftone dots, and the better the reproducibility of the original image. For this reason, in high-quality printing such as art reproduction, high-definition printing using halftone dots having a screen ruling of 200 lines or more has attracted attention, but the problem of uniformity of exposure amount has newly emerged.

That is, when the above-described exposure is performed through a color separation film having halftone dots, an image of the halftone dots is projected on the photoconductor film. In this case, the finer the halftone dots, the more faithfully the halftone dots cannot be reproduced due to the characteristics of the photoconductor film. It is considered that one of the causes of such poor reproducibility is that the problem of tone reproducibility of the photoconductor film cannot be ignored as the dots become finer. That is, for example, a high-contrast film for platemaking is characterized by film characteristics and a development processing system, but has a characteristic that halftone dots are reproduced small when the exposure amount is small and large halftone dots are reproduced when the exposure amount is large. . Therefore, as the number of screen lines increases, adjacent halftone dots affect each other, and it is more important than ever to manage the exposure amount to a constant value.

In this respect, since the exposure amount is the product of the illuminance and the time, the illuminance can be controlled so as to be a constant illuminance by using an illuminance monitor or the like. Regarding the time, the lighting time (using the shutter is used). In the case of a high power source device, the shutter opening / closing time) may be managed. However, considering that the illuminance has a certain distribution on the exposed surface, the above management alone is not sufficient. That is, in the photolithography exposure machine as shown in FIG. 6, the illuminance at the central portion of the set of the plate-making original and the photosensitive film is higher than the illuminance at the peripheral portion. In this case, if the exposure time is set with reference to the peripheral portion having low illuminance, the exposure amount increases in the central portion. That is, the halftone dots are reproduced larger in the central portion than in the peripheral portion. That is, when the conventional photolithography exposure machine shown in FIG. 6 is used, even if the halftone dots of the platemaking original 101 are the same, the sizes of the halftone dots are different between the central portion and the peripheral portion of the photoconductor film. It will be. This means that the color tone is changed between the central portion and the peripheral portion of the finished plate, and the non-uniformity of the illuminance distribution causes the non-uniformity of the color tone of the finished printed matter.

The present invention has been made to solve the above problems, and provides a photolithographic exposure machine in which the unevenness of the illuminance distribution is improved, thereby using a high-definition color separation tone film. It is an object of the present invention to prevent the color tone of a printed matter from being non-uniform even when performing high-resolution printing.

[0014]

In order to achieve the above object, the invention according to claim 1 of the present application has a light source and an optical system built in a machine base, and a transparent glass plate is provided on the upper surface of the machine base. In the photolithography exposure machine, a set of a plate making original and a photoconductor film is placed on the translucent glass plate in an overlapping manner, and the light source is exposed to light while the cover is covered with a cover,
The light source includes a short arc type discharge lamp, and the optical system includes a condenser mirror that collects light from the short arc type discharge lamp, and an illuminance distribution when the light condensed by the condenser mirror is incident. A single rod lens integrator for uniformizing, a condenser lens group that is arranged on the optical path on the exit side of this integrator and that collects light from the integrator and irradiates the translucent glass plate onto the condenser glass group, It has a configuration including an emitting side flat reflecting mirror which is arranged on the emitting side and reflects the light from the condenser lens group toward the translucent glass plate.

Similarly, in order to achieve the above object, the invention according to claim 2 of the present application is such that, in the configuration according to claim 1, the condenser lens group corrects the aberration of the field curvature on the exposure surface to the minus side. It is possible to do so.

[0016] Similarly, in order to achieve the above object, the invention according to claim 3 of the present application is such that in the configuration according to claim 1, the condenser lens group corrects the aberration of the field curvature on the exposure surface to the negative side. And the amount of the correction amount can be adjusted.

Similarly, in order to achieve the above object, the invention according to claim 4 of the present application is the structure according to claim 1, 2 or 3, wherein the short arc type discharge lamp, the condenser mirror, the integrator and the condenser lens are used. And a group are integrally mounted by a frame body in a predetermined optical positional relationship to be assembled as a light source device and are mounted at a predetermined position on a base plate arranged in the machine base, The flat reflecting mirror has a structure in which it is attached to the base plate in a predetermined positional relationship with respect to the attachment position of the light source device to secure an optical position.

Similarly, to achieve the above object, the invention according to claim 5 of the present application is the structure according to claim 1, 2, 3 or 4, wherein the short arc type discharge lamp is a high pressure mercury lamp. have.

Similarly, to achieve the above-mentioned object, the invention according to claim 6 of the present application is the invention as defined in claim 1, 2, 3, 4 or 5.
In the configuration described in (1), the Fresnel lens that collimates the light from the condenser lens group and irradiates the translucent glass plate with the collimated light is disposed below the translucent glass plate.

[0020]

In the invention of claim 1 having the above-mentioned structure, the light from the light source is condensed by the condenser mirror and is incident on the single rod lens type integrator. After propagating in the single rod lens integrator, the light is emitted from the emitting surface and passes through the condenser lens group to irradiate the set of plate-making original and photoconductor film placed on the glass plate for light transmission. To be done. Light irradiation to the set of plate-making original and photoconductor film is such that the light incident from each point on the incident end face of the single rod lens integrator is evenly distributed to the emitting end face, and the image of this emitting end face is projected by the condenser lens group. In this state, the illuminance distribution is made uniform.

According to the second aspect of the present invention, there is provided the above-mentioned first aspect.
In addition to the above function, the negative correction function of the image plane distortion of the condenser lens group reinforces the illuminance of the peripheral portion on the exposure surface, and the illuminance distribution is further uniformized.

According to a third aspect of the present invention, the above-mentioned first aspect is used.
In addition to the above function, the negative correction function of the image plane distortion of the condenser lens group reinforces the illuminance of the peripheral portion on the exposure surface, and the illuminance distribution is further uniformized. At the same time
The amount of negative correction of the image surface distortion aberration is adjusted to obtain the optimum degree of uniform illuminance distribution.

In the structure of claim 4, in addition to the operation of claim 1, 2 or 3, the optical elements of the short arc type discharge lamp, the condenser mirror, the integrator, and the condenser lens group are attached to the frame body. The optical positions of the are positioned. Then, the emission-side flat reflecting mirror is attached to a predetermined position on the base plate to maintain a predetermined optical position with respect to the light source device including the short arc discharge lamp, the condenser mirror, the integrator, and the condenser lens group. It

In the structure of the fifth aspect, in addition to the action of the first, second, third or fourth aspect, the exposure is performed with the light having the wavelength emitted by the high pressure mercury lamp.

In the structure of the sixth aspect, in addition to the above-mentioned operations of the first, second, third, fourth or fifth aspect, the light made into parallel light by the Fresnel lens is incident on the set of the plate-making original and the photosensitive film.

[0026]

Embodiments of the present invention will be described below. Figure 1
FIG. 1 is a side sectional view illustrating a schematic configuration of a first embodiment of a photolithography exposure machine of the present invention. The photolithography exposure machine shown in FIG. 1 is mainly composed of a light source 2 and an optical system 3 which are built in a machine base (not shown), and a translucent glass plate 4. The optical system 3 is a condenser mirror 3 that condenses the light from the light source 2.
1, a single rod lens integrator 34 on which the condensed light enters, a condenser lens group 35 provided on the optical path on the emission side of the single rod lens integrator 34, and an emission side of the condenser lens group 35. And an emission-side flat reflecting mirror 36 for reflecting the light from the condenser lens group 35 toward the translucent glass plate 4.

First, although not shown in FIG. 1, the machine base is a substantially rectangular parallelepiped box-shaped body, and its upper surface is an opening. The translucent glass plate 4 is provided so as to be fitted into the opening on the upper surface of the machine base. The translucent glass plate 4 is made of a material that transmits light having an exposure wavelength as described later. As the light source 2, a short arc type discharge lamp is used. In this embodiment, the short arc type discharge lamp has a rated power of 3
A high-pressure mercury lamp with a gap between the electrodes of 50 W and a distance of 2.8 mm is used. The short arc type is one of the major features of this embodiment. One of the reasons for using the short arc type is because it is related to the configuration for uniforming the illuminance distribution using the single rod lens integrator 34 described later. If a short arc type discharge lamp, that is, a light source with a small arc (light emitting portion) is used, the light can be focused on a very small point by the focusing mirror 31. As a result, the uniform illuminance of the single rod lens integrator 34, which will be described later, is sufficiently exerted.

There is no general definition as to what the arc length is shorter than or equal to "short arc type discharge lamp", but in the present application, the one with an electrode distance of 10 mm or less is used. It is called the short arc type. That is, the “short arc type discharge lamp” in the present application has a pair of electrodes and the distance between the electrodes is 10 mm or less. Furthermore, since it is a "short arc", strictly speaking, the length of the arc should be a problem, but as a practical matter, which region of the space between the pair of electrodes is in the "arc" state. Since it cannot be uniquely determined, the distance between electrodes is used instead. In the present application, the term “high-pressure mercury lamp” generally refers to a mercury lamp having an internal pressure (internal pressure of the sealing body) of 10 atm or more when lit, and the light source 2 used in this example is also the same. is there. Mercury lamps such as high-pressure mercury lamps are known to abundantly emit light of wavelengths in the ultraviolet region near 365 nm, 405 nm, and 436 nm, and a photoconductor film having sensitivity to light of these wavelengths. It is preferably used for exposure of 102. It should be noted that choosing light in the ultraviolet range as the exposure wavelength has the advantage that normal indoor lighting fixtures do not emit light of these wavelengths, so it is possible to work in normal indoor lighting environments without using a dark room. There is.

Next, the optical system 3 will be described. First,
As the condenser mirror 31 for condensing the light from the light source 2, an elliptical condenser mirror is used in this embodiment. The condenser mirror 31 is arranged so as to surround the arc portion of the light source 2 from above, and is arranged so that the position of the first focus thereof is the center position of the arc of the light source 2. Specifically, this positional relationship is achieved by adjusting the position of the light source 2. That is, the condenser mirror 31 is positioned at a fixed position by the frame body 5, and the light source 2 has the position adjusting mechanism 2
1 is attached. Therefore, the position adjusting mechanism 21 is operated to move the position of the arc of the light source 2, and the light source 2 is positioned at a position where the center position of the arc is the position of the first focal point of the condenser mirror 31. The second focal point of the condenser mirror 31 is at the center position of the incident end face of the single rod lens integrator 34, which will be described later. As the configuration of the condensing mirror 31, there is used quartz or other high melting point glass molded in the shape of a semi-elliptical sulfur having aluminum vapor deposition on the front surface or the back surface. As another configuration, aluminum itself may be formed into a rotational semi-elliptical shape, or a reflective material other than aluminum may be used. The condensing mirror 31 is not a complete semi-elliptical shape of rotation, and has a small opening at the top for inserting the stem of the light source 2. Further, instead of the elliptical focusing mirror, it is optically equivalent even if a set of a parabolic mirror and a focusing lens (or a focusing mirror) that reflects the light from the light source 2 into parallel light is adopted. .

In addition, in the optical system 3 of this embodiment, a spherical mirror 32 is additionally employed in addition to the condenser mirror 31. The spherical mirror 32 is a hemispherical mirror, and is arranged so as to surround the light source 2 from below. The spherical mirror 32 is arranged in such a positional relationship that the center of the sphere becomes the center of the arc of the light source 2, that is, the position of the first focal point of the condenser mirror 31. Needless to say, the spherical mirror 32 is adopted to improve the light utilization efficiency. That is, the light emitted obliquely downward from the light source 2 is reflected, returned to the position of the arc again, and condensed by the condenser mirror 31 for use.

The light condensed by the condenser mirror 31 is incident on the single rod lens type integrator 34, and an incident side plane reflecting mirror 33 is arranged in the optical path thereof. The incident side plane reflecting mirror 33 is arranged in a state of being tilted at 45 degrees with respect to the optical axis (the central axis of the light source 2, the condenser mirror 31, and the spherical mirror 32), and the vertical optical axis is bent at a right angle to the horizontal direction. Is working to In addition, this incident-side flat reflecting mirror 33
Is a dichroic mirror having a predetermined wavelength selection function. Specifically, the incident side flat reflecting mirror 33 is
A glass having a predetermined wavelength selection film formed on the front surface (or the back surface) of high melting point glass such as quartz is adopted. This wavelength selective film reflects light with a wavelength of 436 nanometers or less,
It is a film that transmits light of a longer wavelength than that. That is, light on the long wavelength side that is not used for exposure is transmitted and removed from the optical path, and the light-transmitting glass plate 4 or the photoconductor film 102 is transmitted.
It is designed to prevent the temperature from rising.

A single rod lens type integrator 34 is arranged at a position where the light condensed by the condenser mirror 31 enters. Single rod lens type integrator 34
As its name suggests, the integrator is composed of one rod lens, and is arranged in a horizontal posture such that the length direction of the rod lens coincides with the optical axis. This single rod lens type integrator 34
The action of will be described later.

A condenser lens group 35 is arranged on the optical path on the exit side of the single rod lens type integrator 34. The condenser lens group 35 is for condensing the light emitted from the single rod lens type integrator 34 and for uniformly irradiating the light to the translucent glass plate 4, and is formed by combining a plurality of lenses. As a whole, it works as a condenser lens. And the distance between the lenses is adjustable,
This makes it possible to adjust the peripheral illuminance correction, which will be described later.

On the optical path on the exit side of the condenser lens group 35, an exit-side flat reflecting mirror 36 is arranged. The exit-side flat reflecting mirror 36 is arranged at an angle of 45 degrees with respect to the optical axis, and reflects the light from the condenser lens group 35 upward.

The light reflected by the exit-side plane reflecting mirror 36 is incident on the transparent glass plate 4 arranged above, but in this embodiment, the Fresnel lens 37 is provided below the transparent glass plate 4. Is equipped with. The Fresnel lens 37 is arranged in a posture parallel to the horizontal light-transmitting glass plate 4, and is provided for the purpose of converting light into parallel light. That is, the Fresnel lens 37 is optically equivalent to the collimator lens. The Fresnel lens 37 is attached with a structure sandwiched between two translucent glasses (not shown).
As for the material, it is made of resin such as acrylic, and is manufactured by a method such as injection molding. Needless to say, it may be made of a glass material such as quartz.

Except for the emitting side plane reflecting mirror 36 and the Fresnel lens 37, the respective elements constituting the optical system 3 as described above are integrally attached to the frame body 5 in the above-mentioned optical relationship and assembled as a light source device 30. Has been. This frame 5
Is a condenser mirror 31, a spherical mirror 32, an incident side plane reflecting mirror 33, and a single rod lens type integrator 34 at the positions described above.
Has a mounting portion for mounting. Further, a base plate 8 is horizontally provided on the bottom surface of a machine base (not shown), and the frame 5 is fixed at a predetermined position on the base plate 8 so that the entire light source device 30 is a base plate. It is fixed at a predetermined position with respect to 8.

On the other hand, the exit side plane reflecting mirror 36 is held by holding plates 361 extending downward from both ends thereof,
The lower part of the holding plate 361 is fixed at a predetermined position on the base plate 8. As a result, the emission-side plane reflecting mirror 36 maintains a predetermined positional relationship with the light source device 30. Further, in the photolithography exposure machine of this embodiment, the illuminance sensor 6 is arranged to constantly monitor the illuminance on the exposure surface. The illuminance sensor 6 is arranged near the end of the Fresnel lens 37, and the plane mirror 3 on the exit side is reflected.
A part of the light reflected from 6 is received and its intensity is detected. In addition, the photolithography exposure machine of this embodiment is provided with a cover mechanism (not shown) for covering the set of the plate-making original 101 and the photoconductor film 102 placed on the translucent glass plate 4, as in the conventional case.

The photolithographic exposure machine of this embodiment having the above-mentioned structure operates as follows. That is, a predetermined photoconductor film 102 is superposed on the plate-making original 101 produced in advance as described above in a predetermined positional relationship and placed on the translucent glass plate 4. Then, a cover mechanism (not shown) is operated to make the plate-making original 101 and the photoconductor film 102.
The set is covered with a cover, and is closely attached by a vacuum suction mechanism. In this state, the light source 2 is turned on for exposure. The light from the light source 2 is reflected by the incident side plane reflecting mirror 33 while being collected by the condenser mirror 31 and the spherical mirror 32, and enters the single rod lens type integrator 34. The light homogenized by the single rod lens type integrator 34 is condensed by the condenser lens group 35, reflected by the exit side plane reflecting mirror 36, and enters the upper Fresnel lens 37. Then, it is converted into parallel light by the Fresnel lens 37, transmitted through the light-transmitting glass plate 4, and irradiated onto the group of the plate-making original 101 and the photosensitive film 102. As a result, the photosensitive film 1 is exposed to the light of the pattern drawn on the plate-making original 101.
02 is exposed. It should be noted that the exposure time is preset with an optimum time in relation to the illuminance on the irradiation surface, and the lighting time of the light source 2 or the on / off of a shutter (not shown) is controlled at this time.

Next, the operation of the single rod lens type integrator 34 will be supplementarily described. In general, an integrator as an optical element aims to make the illuminance uniform by separating and integrating light. Hereinafter, in order to show the superiority of the action and effect of the single rod lens type integrator used in the present embodiment, it will be described in comparison with the fly-eye type integrator.

First, FIG. 2 is an optical system explanatory diagram in the case of using the fly-eye type integrator 7 in place of the single rod lens type integrator 34 in the optical system 3 of FIG. 1, and is shown as a reference example. The fly-eye type integrator includes a rod lens type and a double lens type, and FIG. 2 shows a rod lens type. The fly-eye integrator 7 is configured by bundling about several to several tens of rod lenses having a square or circular cross section in a centrally symmetrical manner.

When the fly-eye type integrator 7 is used, a collimator lens 701 is usually used on the incident side thereof, and the light from the light source 2 is collimated by the collimator lens 701 and then made incident on the integrator 7. . A field lens 702 is provided on the exit side of the integrator 7 so that the projection patterns of the rod lenses overlap at the same position. In the optical system shown in FIG. 2, the light from the light source 2 is collimated by the collimator lens 701, and enters the integrator 7 as a light beam that extends over the incident surfaces of all the rod lenses. Then, the light propagates through each rod lens and is emitted from the emission surface of each rod lens, and is superposed at the same position on the irradiation surface by the field lens 702 to achieve uniform illuminance distribution.

FIG. 3 is an explanatory view of the illuminance distribution uniformizing action by the integrator 7 of FIG. In FIG. 3, Ii indicates the illuminance distribution on the incident surface of the integrator 7, and I70,
I71 and I72 indicate the illuminance distribution of the image projected by the rod lens 70, the illuminance distribution of the image projected by the rod 71, and the illuminance distribution of the image projected by the rod lens 72, respectively. First, the illuminance distribution on the incident surface, that is, the integrator 7
The intensity distribution Ii of light incident on is strongest near the optical axis and weaker toward the periphery as shown in the figure. Of the light emitted from the rod lenses 70, 71, 72, the illuminance distribution I71 of the light emitted from the rod lens 71 on the optical axis is the illuminance distribution I on the incident surface.
The distribution is such that the distribution of i near the optical axis is extracted and enlarged. That is, the distribution is strong near the optical axis and gradually weakens toward the periphery. On the other hand, the illuminance distribution I due to the light emitted from the rod lenses 70 and 72 located at a position away from the optical axis
70 and I72 are distributions in which the illuminance distribution on the incident surface is inverted and enlarged, and are distributions that are stronger in the peripheral portion on the opposite side and weaker as they approach the optical axis. When such three intensity distributions I70, I71, and I72 are superposed, the weak portion in the peripheral portion is strengthened to obtain a uniform illuminance distribution.

On the other hand, FIGS. 4 and 5 are diagrams for explaining the operation of the single rod lens type integrator 34 in the first embodiment of FIG. 1, FIG. 4 is an explanatory diagram of the entire optical system, and FIG. 5 is a rod lens. It is explanatory drawing of the light ray which propagates inside. As described above, the single rod lens type integrator 34 constitutes an integrator by one rod lens 341, and therefore the operating principle thereof is slightly different from that shown in FIG. That is, the light from the light source 2 is emitted from the rod lens 341.
Part of the light entering from one end surface of the rod lens 34
The light propagates through the rod lens 341 while being totally reflected on one side surface, and is emitted from the other end surface. At this time, a light ray incident on a certain point on the incident end surface of the rod lens 341 is dispersed to each point on the outgoing end surface of the rod lens 341 according to the incident angle, and as a result, the illuminance distribution is made uniform. .

This point will be described in more detail with reference to FIG. In FIG. 5, FIG. 5 (A) shows the trajectory of the light beam that has entered the rod lens 341 from the center (point on the optical axis) of the incident end face. Then, as shown in FIG.
(C), (D), (E) is a diagram in which the light beam of (A) is separated according to the number of total reflections on the side surface of the rod lens 341. First, as shown in FIG. 5B, when the incident angle is small within a predetermined range, the light beam spreads over the entire emission end face without being totally reflected and is emitted directly from the emission end face. Needless to say, how small the incident angle becomes as in (B) depends on the length and cross section of the rod lens 341. In this embodiment, a rod lens having a length of about 100 mm is used. Next, with respect to a light beam having a predetermined incident angle as the center and an incident angle deviated within a predetermined range from the light beam, the light beam is totally reflected once on the side surface of the rod lens 341 as shown in FIG. 5C. To do. After all, this light beam also spreads and is emitted to the entire emission end face of the rod lens 341. Further, with respect to a light beam having a predetermined incident angle larger than that of (C) as a center and the incident angle being deviated within plus or minus within a predetermined range from the light ray, FIG.
As shown in (D), the side surface of the rod lens 341 is totally reflected twice. After all, this light beam also spreads and is emitted to the entire emission end face of the rod lens 341. Further, with respect to a ray whose center of incidence is larger than that of (D) and whose incident angle deviates within a predetermined range from the ray, as shown in FIG. Totally reflects three times on the side. After all, this ray also spreads and is emitted to the entire emission end face of the rod lens 341.

As described above, the light rays incident from a certain point, that is, the center of the incident end surface, are spread and dispersed over the entire exit end surface. This state is (B), (C), (D),
It is better understood by (A) superimposing (E). Such dispersion of light over the entire exit end face similarly occurs for light incident from other points on the entrance end face. That is, at each point on the incident end surface, the incident light beam is dispersed on the exit end surface. As a result, uniform illuminance distribution is achieved. That is, on the incident end face of the rod lens 341, even if the illuminance distribution is Ii in FIG. 3, the incident light at each point is similarly dispersed to the emitting end face, and as a result, the illuminance distribution on the emitting end face becomes uniform. Of. Since the light from the emission end face spreads as shown in FIG. 6, the condenser lens group 35 collects the light and projects the image of the emission end face on the irradiation surface. Therefore, for the condenser lens group 35, the emission end surface of the rod lens 341 is the object point, and the irradiation surface (the surface of the photoconductor film 102 in FIG. 1) is the image point.

Now, the single rod lens type integrator 34 shown in FIG. 4 is very excellent in adjusting the degree of reinforcement of peripheral illuminance, as compared with the fly-eye type integrator shown in FIG. This point will be described below. That is,
In the single rod lens integrator 34 shown in FIG. 4, the degree of reinforcement of peripheral illuminance can be adjusted by providing the condenser lens group 35 arranged on the exit side with a function of negative image plane distortion. . Specifically, the image plane distortion aberration means an aberration in which an image is distorted and projected.For example, when a rectangular shape is projected, the image is distorted like a pincushion, that is, a peripheral portion is stretched, or a barrel. The shape, that is, the peripheral portion is distorted as if it contracts. Then, it is said that when correcting the image surface distortion in the direction in which the image is distorted in a pincushion shape, the correction is a positive correction or in the positive side. It is said that it will be corrected to.
When the minus correction is performed, the luminous flux density becomes high in the peripheral portion, so that the illuminance in the peripheral portion is reinforced as a result. In the optical system shown in FIG. 6, the condenser lens group 35
It is easy to properly design and perform negative correction. Further, by designing the aberration correcting lens arbitrarily, the correction amount at that time can be arbitrarily selected, and as a result, the degree of reinforcement of the peripheral illuminance can be freely adjusted.

On the other hand, in the fly-eye type integrator 7 shown in FIG. 2, it is practically impossible to reinforce the peripheral illuminance by adjusting the image plane distortion. This is because in the fly-eye integrator, the light rays (70C, 71C, 72C in FIG. 3) that form an image at the center of the irradiation surface and the light rays (70L, 71L, 72L, and 70L that form an image in the peripheral area).
U, 71U, 72U) occupy almost the same position on the optical path so as to overlap in the vicinity of the emission end face of the integrator 7, and are not dispersed as in FIG. Of course, at a position distant from the exit end face of the integrator 7, the light beam connected to the center and the light beam connected to the peripheral part are separated, so a lens for minus correction is provided at such a position to reinforce the peripheral illuminance. It is possible to adjust. However, at such a distant position, the area occupied by the light beam becomes very large, so that a large lens is required, which makes optical design very difficult.

As described above, in this embodiment, it is possible to adjust the reinforcement of the peripheral illuminance by adjusting the aberration of the negative image plane distortion, but in reality, the condenser lens group 3 is used.
The design is such that the degree of negative image plane distortion can be adjusted by changing the distance between the front lens group and the rear lens group in No. 5. The frame body 5 in FIG. 1 is provided with an adjusting unit for this interval.

One of the reasons why the degree of reinforcement of the peripheral illuminance can be adjusted as described above in this embodiment is as follows.
This is related to the adoption of the Fresnel lens 37. That is, FIG.
When the Fresnel lens 37 as shown in (1) is used, the light loss in the peripheral portion increases. Therefore, when the Fresnel lens 37 is used, it is necessary to reinforce the peripheral illuminance to a greater extent than when the Fresnel lens 37 is not used. The Fresnel lens 37 may not be used if the above-mentioned misregistration in the peripheral portion does not pose a problem. In addition, regardless of whether the Fresnel lens 37 is used or not, it is needless to say that the adjustment of the degree of reinforcement of the peripheral illuminance is beneficial in the sense of obtaining a desired illuminance uniformity. Further, in the case of the single rod lens integrator 34, the pattern of the image obtained on the irradiation surface depends on the sectional shape of the rod lens 341. If the rod lens 341 has a circular cross section, a round light beam can be obtained, and if the rod lens 341 has a rectangular cross section, a rectangular light beam can be obtained. In the present embodiment, the translucent glass plate 4 has a rectangular shape, so that 1
A rod lens 341 having a rectangular cross section of about 2.4 mm × 17 mm is used.

When the optical system 3 having the above-described structure was actually manufactured, the illuminance distribution within ± 5% was achieved on the irradiation surface of about 920 mm × 1200 mm. That is, when the highest illuminance portion in the central portion was taken as 100%, 90% or more illuminance was obtained even in the lowest illuminance portion in the peripheral portion. By using the photolithography exposure machine of this embodiment capable of exposing with such a high uniformity of illuminance distribution, even in the case of a plate-making original using a high-definition color separation tone film as described above, Reproduction of the dots becomes almost constant in the center and the peripheral portion of the photoconductor film, and it is possible to perform excellent plate making without uneven color tone of the printed matter.

Next, a second embodiment of the photolithography exposure machine of the present invention will be described. 6 and 7 are views for explaining the outline of the photolithography exposure machine of the second embodiment, FIG. 6 is a front view thereof, and FIG. 7 is a side view thereof. In the second embodiment, the condenser lens group 35 and the exit side plane reflecting mirror 3 are provided.
Further, another plane reflecting mirror is provided as an emission-side auxiliary plane reflecting mirror 38 between the plane mirror 6 and 6. That is, in the second embodiment, two plane reflecting mirrors 36 and 38 are used on the exit side of the condenser lens group 35 to refract the optical path, thereby making the structure more compact. Specifically, the light source device 3
The light emitted from 0 has an optical axis in the first direction, and the emission side auxiliary plane reflecting mirror 38 refracts this optical axis in the second direction perpendicular to the first direction. Then, the exit side plane reflecting mirror 3
6 refracts the optical axis in the second direction vertically upward. The first direction and the second direction may be horizontal, but in order to make the entire exposure machine compact, etc.
It may be set in a state of being inclined at a predetermined angle with respect to the horizontal.

Further, as is apparent from FIGS. 6 and 7, the emitting side plane reflecting mirror 36 and the emitting side auxiliary plane reflecting mirror 38 have a trapezoidal shape as shown in the figure. This is because the light from the light source 2 is used as effectively as possible to irradiate the translucent glass plate 4. In the second embodiment as well, as in the first embodiment, the base plate 8 is fixed on the bottom surface of the machine base 1,
A light source device 30 as shown in FIG. 1 is fixed at a predetermined position above it. The emission side flat reflecting mirror 36 and the emission side auxiliary flat reflecting mirror 38 are held by a holding plate (not shown), and the holding plate is fixed at a predetermined position on the base plate 8. As a result, the emission-side plane reflecting mirror 36 and the emission-side auxiliary plane reflecting mirror 38 hold the optical position. Other configurations and operational effects are basically the same as those in the case of the first embodiment described above, and therefore description thereof will be omitted.

In the photolithography exposure machine of each of the embodiments described above, the use of the flat reflecting mirrors 33, 36, 38 helps to reduce the size of the exposure machine as a whole. That is, the light source 2
In the configuration in which the light of the short arc type discharge lamp as described above is condensed by the condensing mirror 31 and is made uniform by the single rod lens type integrator 34, the focal length of the condensing mirror 31 is lengthened to condense into a smaller light beam. It is preferable to do so to make the illuminance uniform. However, if the focal length of the condenser mirror 31 is made long, the optical path length becomes long, and as a result, the size of the entire exposure apparatus becomes large. As in the present embodiment, the plane reflecting mirrors 33, 3
If the optical path is bent by appropriately using 6, 38, the optical system can be compactly housed inside the machine stand while making the optical path length long, which remarkably contributes to downsizing of the exposure apparatus as a whole. Two flat reflecting mirrors 33 and 36 are used in the first embodiment, and three flat reflecting mirrors 33, 36 and 38 are used in the second embodiment, but in some cases one flat reflecting mirror may be sufficient. Of course, it may be preferable to use four or more plane reflecting mirrors. In addition, in the present specification, the “photoreceptor film” is not limited to a flexible so-called film-shaped film, but also includes a non-flexible film. What is essential is that it has a photosensitive layer that can be exposed to the light of the pattern of the plate-making original.

[0054]

As described above, according to the invention as set forth in claim 1 of the present application, even when printing with high resolution by using a high-definition color separation length film, a printed matter can be obtained. It is possible to perform excellent plate making without causing uneven color tone of the. In addition, the use of the plane reflecting mirror reduces the size of the entire exposure machine. In addition, claim 2
According to the invention described in (1), in addition to the effect of the first aspect, the illuminance in the peripheral portion can be reinforced and the illuminance can be further uniformized by the negative correction of the image surface distortion. Further, according to the invention of claim 3, in addition to the effect of claim 1, negative correction of the image surface distortion can reinforce the illuminance of the peripheral portion to further uniformize the illuminance, and ,
Since the correction amount at that time can be adjusted, the degree of reinforcement of the peripheral illuminance can be freely adjusted. In addition, claim 4
According to the invention described in (1), in addition to the effects of the first, second or third aspect, the optical positions of the elements constituting the optical system can be easily positioned, so that the exposure machine can be manufactured easily. According to the invention described in claim 5, the above-mentioned claim 1,
In addition to the effects of 2, 3 or 4, it is possible to select light in the ultraviolet range from a high-pressure mercury lamp as the exposure photosensitive wavelength, and by using a lighting fixture that does not emit light of such a wavelength, work in a bright room can be performed. The effect that it becomes possible is obtained. Further, according to the invention of claim 6, in addition to the effect of claim 1, 2, 3, 4 or 5, since the light that has become parallel light is incident on the set of the plate-making original and the photoconductor film, Misregistration in the department is prevented. At this time, the degree of nonuniformity of the illuminance distribution changes due to the use of the Fresnel lens, and this change can be compensated by adjusting the correction amount of the negative correction of the image plane distortion by the condenser lens group.

[Brief description of drawings]

FIG. 1 is a side sectional view illustrating a schematic configuration of an exposure machine for photoengraving according to an embodiment.

2 is an optical system explanatory diagram in the case of using a fly-eye integrator 7 in place of the single rod lens integrator 34 in the optical system 3 of FIG. 1, and is a diagram shown as a reference example.

FIG. 3 is an explanatory diagram of an illuminance distribution uniformizing action by the integrator 7 of FIG.

FIG. 4 is a view for explaining the operation of the single rod lens type integrator 34 in the first embodiment of FIG. 1, and is an explanatory view of the entire optical system.

5 is a view for explaining the operation of the single rod lens integrator 34 in the first embodiment of FIG. 1, and is an explanatory diagram of light rays propagating in the rod lens.

FIG. 6 is a front view illustrating the outline of a photolithography exposure machine according to a second embodiment.

FIG. 7 is a side view illustrating the outline of a photolithography exposure machine according to a second embodiment.

FIG. 8 is a side sectional view illustrating a schematic configuration of a conventional photolithography exposure machine.

[Explanation of symbols]

 1 Machine Stand 2 Light Source 3 Optical System 31 Condenser Mirror 32 Spherical Mirror 33 Incident Side Plane Reflector 34 Single Rod Lens Integrator 35 Condenser Lens Group 36 Ejection Side Plane Reflector 37 Fresnel Lens 38 Ejection Side Auxiliary Plane Reflector 4 Translucent Glass plate 5 Frame 6 Illuminance sensor 101 Plate making original 102 Photosensitive film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Hisashi Muto 1-7-1 Kanda, Chiyoda-ku, Tokyo Ushioyutech Co., Ltd. (72) Inventor Nobuyoshi Furukawa 1-7-1, Kanda, Chiyoda-ku, Tokyo Ushioyutech Co., Ltd. (72) Inventor Mitsuyoshi Koizumi 2-6-2 Otemachi, Chiyoda-ku, Tokyo Hitachi Electronic Engineering Co., Ltd.

Claims (6)

[Claims] 1. A light source and an optical system are built in the machine stand, a light-transmitting glass plate is provided on the upper surface of the machine stand, and a set of a plate-making original and a photoconductor film is placed on the light-transmitting glass plate in an overlapping manner. In the exposure machine for photoengraving in which the light source is turned on and exposed with the cover covered with a cover, the light source is a short arc type discharge lamp, and the optical system is the short arc type discharge lamp. Is placed on the optical path on the exit side of this integrator, and a single-rod-lens integrator that collects the light from the A condenser lens group that collects the light from the integrator and irradiates it onto the light-transmitting glass plate, and an emission that is arranged on the emission side of the condenser lens group and reflects the light from the condenser lens group toward the light-transmitting glass plate. Photolithographic exposure machine, characterized in that the more the plane reflecting mirror. 2. The photolithographic exposure apparatus according to claim 1, wherein the condenser lens group is capable of correcting the aberration of the field curvature on the exposure surface to the negative side. 3. The condenser lens group is capable of correcting the aberration of the curvature of field on the exposure surface to the negative side, and is capable of adjusting the magnitude of the correction amount. The photolithographic exposure machine according to claim 1. 4. A short arc type discharge lamp, a condenser mirror, an integrator, and a condenser lens group are integrally attached by a frame body in a predetermined optical positional relationship to be assembled as a light source device and at the same time in the machine base. Is mounted at a predetermined position on the base plate arranged on the base plate, and the emission-side flat reflecting mirror is mounted on the base plate in a predetermined positional relationship with the mounting position of the light source device to ensure an optical position. 4. The method according to claim 1, 2 or 3, wherein
The exposure machine for photoengraving described in. 5. The photolithographic exposure machine according to claim 1, wherein the short arc type discharge lamp is a high pressure mercury lamp. 6. A Fresnel lens for converting the light from the condenser lens group into parallel light and irradiating it onto a light-transmitting glass plate is provided below the light-transmitting glass plate. The exposure machine for photoengraving according to 2, 3, 4 or 5.