JP2537277B2 - Scanning optics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention scans a photosensitive material using a plurality of light beams,
Accordingly, the present invention relates to a scanning optical system used when drawing on a photosensitive material, and more particularly to a technique for changing the spot diameter and the pixel pitch of a light beam on the photosensitive material independently of each other.

[Conventional technology]

For the purpose of shortening the drawing time in a laser plotter that records a desired image as a binary image of white / black on a photosensitive material, or a plate making scanner that records a gradation image using halftone dots on the photosensitive material. , A scanning optical system using a plurality of laser beams (multi-beam scanning system) is used.

FIG. 30 is a diagram showing a scanning locus by such a multi-beam scanning system, in which scanning lines L _{1 to} L ₁₁ extending along the main scanning direction X are arranged along the sub scanning direction Y. Taking the case where the drawing along the scanning locus is performed using two laser beams as an example, the two beam spots SP ₁ and SP ₂ having the beam spot diameter d on the photosensitive material are separated by the distance l.
The multi-beam scanning system is adjusted so that they are formed apart from each other. However, the distance l satisfies l = (2n-1) P (1) with respect to the pixel pitch (scanning line pitch) P, and n is a natural number (n = 2 in the case shown). .

Then, as indicated by arrow pair AR ₁ , for example, scan line L
While scanning the same time the ₁ and L _4, respectively and the beam spot SP ₁ and SP _2, a beam spot SP ₁ and SP _2, is moved by relative 2P against the photosensitive material surface, the scanning line L ₃ Perform a scan on L ₆ and. By repeatedly performing such feeding in the sub-scanning direction Y and main scanning, the arrow pair AR ₁
The traveling scanning indicated by AR ₄ is sequentially performed. as a result,
In the figure, the odd-numbered scanning lines L ₁ , L ₃ , L ₅ , ..., L ₁₁ shown in white
Is the first beam spot SP ₁ and the even-numbered scanning lines L ₂ , L ₄ , ..., L ₁₀ are the second beam spot SP ₂
Will be scanned respectively.

[Problems to be Solved by the Invention]

By the way, in scanning using a light beam, the pixel pitch P may be increased in order to improve the drawing speed, or conversely, the pixel pitch P may be decreased in order to improve the drawing density. When such a pixel pitch change is performed in a scanning optical system using a single beam, it suffices to simply change the image data supply clock or the scanning speed, but a unique problem occurs in the multi-beam scanning system.
That is, when different pixel pitches are P ₁ and P ₂ , respectively, there are natural numbers n ₁ and n ₂ that satisfy (2n ₁ -1) P ₁ = (2n ₂ -1) P ₂ (2) Except cases, the pixel pitches P ₁ and P ₂ cannot be mutually changed unless the mutual distance between the beam spots SP ₁ and SP ₂ is changed. In other words,
In order to perform scanning at the pixel pitch P ₁ , the mutual distance between the _two beam spots SP ₁ and SP ₂ must be l ₁ = (2n ₁ −1) P ₁ (3), while In order to perform scanning with the pixel pitch P ₂ of, the mutual distance must be l ₂ = (2n ₂ −1) P ₂ (4), so if the condition of equation (2) is not satisfied, That is, l ₁ ≠ l ₂ .

In this way, when it becomes necessary to change the mutual distance l, the reduction ratio of the entire beam image on the photosensitive material is changed by changing the magnification of the reduction optical system in the multi-beam scanning system. Can also be considered. However, if such a method is simply applied, the spot diameter d will also change, and therefore the demand for changing only the mutual distance 1 (and therefore the pixel pitch) cannot be satisfied. Further, for the same reason, it is impossible to change only the spot diameter d without changing the pixel pitch.

On the other hand, in a recording apparatus that achieves sub-scanning by relatively moving the scanning optical system and a photosensitive material while performing main scanning by periodically deflecting one or more light beams, It is known that the scanning line is tilted with the movement for the purpose. As an example of this situation, in the photosensitive material 1 of FIG. 31A, the drawing area 2 is conceptually divided into a plurality of parallel strips (stripes) 2a, 2b, ... 2z, and the parallel strips 2a to 2z are sequentially arranged. Consider the case of drawing. In this way, by moving the light beam to the photosensitive material 1 while periodically deflected in the X direction (-Y) direction, firstly the first strip from the position of Y = Y _A to the position of Y = Y _B
Drawing inside 2a. The same applies to the other strips 2b to 2z. Such a divided writing method has an advantage that a deflection error or the like is less likely to occur because the laser beam deflection angle may be smaller than a method of deflecting the laser beam over the entire width of the writing target area 2. Further, if the deflection width is narrow, the focal length of the scanning instep lens can be shortened, so that the diameter of the scanning beam can be reduced accordingly and a finer pattern can be drawn. Further, as compared with the method in which both the main scanning and the sub-scanning are achieved only by the mechanical relative movement of the scanning optical system and the photosensitive material 1, the mechanical movement of the member having a large mass is small, and therefore the drawing speed is high. There is also an advantage that

Even in such a divided exposure method, assuming that the direction of laser beam deflection is the X direction, the direction in which the beam spot travels on the photosensitive material 1 is the laser beam deflection speed V _X (not shown) and the sub-scanning speed (sensitive material). The scanning line arrangement 4 is an arrangement inclined to the upper right direction in the figure, because the scanning line arrangement 4 is deviated in the direction determined by the ratio of the feed rate V _Y. As a result, the drawn image also becomes tilted.

For each of the strips 2a to 2z, when performing drawing from the position of Y = Y _A in the same direction to the position of Y = Y _B is
A method of compensating for such inclination is known. The simplest method is to compensate the inclination of the scanning line array 4 by fixing the relationship between the moving direction of the photosensitive material 1 and the deflection direction of the laser beam at an angle deviated from 90 degrees. Further, Japanese Patent Laid-Open No. 55-111917 discloses a technique of compensating for the above-mentioned inclination by deflecting the laser beam also in the sub-scanning direction.

By the way, in the above-mentioned single-direction sub-scanning, when the drawing of the next strip 2b is completed after the drawing of one strip 2a is completed, the photosensitive material 1 has to be sent back in the Y direction, which causes a loss due to a waiting time. Therefore, there is a demand for a reciprocating scanning device that scans even-numbered strips from the position Y = Y _B toward the position Y = Y _A.

In the case of reciprocal scanning, the sub-scanning directions are opposite between the odd-numbered strips and the even-numbered strips, so that the inclination of the scanning line array 4 is different between the odd-numbered strips and the even-numbered strips, as shown in FIG. 31B. Then the opposite is true. Therefore, using the conventional compensation method as described above, the 31C
As shown in the figure, even if the slope in the odd-numbered strip can be compensated, the slope in the even-numbered strip becomes rather large. Further, when the speeds V _X and V _Y are changed, the inclination of the scanning line also changes.

As described above, the inclination of the scanning line occurs in various situations. However, as will be described later, when the pixel pitch and the spot diameter are independently changed in the multi-beam scanning system, the compensation for the inclination of the scanning line is particularly effective. It is desirable to do. However, since the conventional tilt compensation method is not conscious of such a situation, it is desired to develop a tilt compensation that matches this situation for improvement for independently changing the pixel pitch and the spot diameter.

[Object of the Invention]

The present invention is intended to solve the above-mentioned problems of the prior art, and first, to provide a multi-beam type scanning optical system capable of independently changing the pixel pitch with a simple configuration. The purpose of 1.

The second purpose is to make it possible to independently change the spot size in addition to the drawing pitch.

Further, in achieving the above two objects, it is a third object of the present invention to eliminate the inclination of the scanning lines on the forward path side and the backward path side in the reciprocal scanning.

[Means for Solving the Problem] In order to achieve the first object, according to the first configuration of the present invention, a beam group including a plurality of modulated light beams is periodically deflected, A scanning optical system used for sequentially exposing the drawing areas on the photosensitive material by relatively moving the photosensitive material and the beam group while scanning the photosensitive material with the beam group, ) Beam redirecting means for redirecting the plurality of modulated light beams into a first light beam group intersecting at a predetermined point; and (b) the beam redirecting means coupled to the beam redirecting means. Crossing angle changing means for changing the crossing angle of the first light beam group at the predetermined point by giving a rotational displacement to (c) the first light beam group arranged at the predetermined point. Cyclically deflected, which causes a second And a condensing means for condensing each of the light beams belonging to the second light beam group on the photosensitive material. Further, the center of the rotational displacement of the beam direction changing means by the intersecting angle changing means is moved from the intersecting angle changing means to the deflecting means side by a distance about twice the distance from the intersecting angle changing means to the deflecting means. The points are separated.

Moreover, in the second configuration of the present invention,
An optical system having a variable focal length optical system is used.

Furthermore, in the third configuration of the present invention, the above (a) to
In addition to the means of (d), (e) a deflection direction rotation means which is interposed between the deflection means and the light condensing means and rotates the deflection direction of the second light beam group, ) Rotation angle changing means coupled to the deflection direction rotation means for changing the rotation angle in the deflection direction of the second light beam group by rotating the deflection direction rotation means, and (g) the sensitive material. A reciprocating means for relatively reciprocating the beam group in the relative movement direction; and (h) a direction control means for controlling the rotation direction of the deflection direction rotation means based on the relative movement direction, Is added.

[Action]

In a multi-beam scanning system, a plurality of light beams generally travel on predetermined optical paths.
Is a first light beam group that receives these and intersects at a predetermined point. Further, since the "intersection angle changing means" is provided, the intersection angle can be arbitrarily changed. Moreover, the "intersection angle changing means" can change the intersection angle only by giving rotational displacement to the "beam direction changing means".

The fact that the crossing angle is changed means that the mutual distances of the plurality of light beams included in the first light beam group after passing through the scan lens can be changed. For this reason,
When a second light beam group that is periodically deflected is obtained by the "deflecting means" arranged at the above-mentioned predetermined point, this second
The mutual divergence of the plurality of light beams included in the light beam group is variable. Therefore, at this stage, a plurality of light beams whose mutual distances can be freely changed can be obtained, and the pixel pitch on the photosensitive material can also be freely changed.

Further, since the deflecting means is arranged at the intersection of the plurality of light beams, these light beams are always directed and incident on the deflecting means even when the mutual spacing of the light beams is changed.
As a result, the light beam does not deviate from the deflecting means. The above is the operation in the first configuration.

In the second configuration of the present invention, the “light condensing unit” includes the variable focal length optical system. When the focal length is changed in this variable focal length optical system, the sizes of a plurality of beam spots on the photosensitive material and their mutual distances are changed at the same time. However, the change in mutual distance between the plurality of beam spots can be compensated by changing the crossing angle by the "crossing angle changing means". As a result, for example, it is possible to change only the spot size while keeping the mutual distance unchanged.

On the other hand, when the pixel pitch is changed, it is generally disadvantageous to change the deflection cycle. Therefore, the relative movement speed between the photosensitive material and the scanning optical system is changed with the deflection cycle kept constant. For example, when the pixel pitch is increased, this relative movement speed is increased. Then, the tilt angle of the scanning line described in FIGS. 31A to 31C also changes. A "deflection direction rotation means" is provided to compensate for this inclination. The rotation angle in the deflection direction can be changed by the "rotation angle changing means", and its value is designated according to the relative moving speed of the photosensitive material and the scanning optical system. Therefore, the problem of the inclination of the scanning line due to the change of the pixel pitch is solved. Further, when performing reciprocal scanning, by controlling the rotation direction of the deflection direction rotating means on the forward path side and the backward path side based on the relative movement direction, the inclination of the scanning line corresponding to the forward path side and the backward path side respectively. Also compensate.

〔Example〕

Embodiments of the present invention will be described below. First, the schematic configuration and operation of a novel drawing system incorporating the scanning optical system according to the embodiment will be described. After that, details of the scanning optical system will be described, and finally, a modification will be described.

A. Drawing System (A-1) Mechanical Structure and Operation FIG. 1 is a perspective view of a drawing system 100 incorporating a scanning optical system according to an embodiment of the present invention. Drawing system 100
On the base 10, a sensitive material feeding mechanism 20 and a drawing mechanism 30 are provided. The sensitive material feeding mechanism 20 has a suction table 21, and the sensitive material 1 such as a glass plate is adsorbed on the suction table 21.

The suction table 21 is a pair of guides extending in the horizontal Y direction.
It is slidably mounted on 22 and is rotated by a motor (not shown) by a ball screw (± Y).
Move back and forth in the direction. As a result, the sensitive material 1 is also (±
Reciprocate in the Y) direction.

On the other hand, the drawing mechanism 30 has a pair of guides 31 extending in the horizontal X direction. However, the X direction is a direction perpendicular to the Y direction. A housing 32 is slidably mounted on the guide 31, and the scanning optical system 200 according to the embodiment of the present invention is housed in the housing 32. The drawing head 33 shown in the notch in the drawing is a part of the scanning optical system 200. When the ball screw 35 is rotated by the motor 34, the scanning optical system 200 moves in the X direction or the (−X) direction according to the housing 32. As a result, the drawing head 33 also moves in the X direction or the (-X) direction.

On the upper surface of the base 10, a He-Ne laser oscillator 40 is provided. Laser light 41 from this He-Ne laser oscillator 40
Are divided into two laser beams 41 by beam splitters 42 to 45.
Separated into X and 41Y. However, beam splitters 44 and 45
Are fixed to the drawing head 33. Plane mirrors 46X and 46Y are provided upright at the X direction end and the (-Y) direction end of the suction table 21, respectively. Then, the laser light 41
X and 41Y are reflected by these mirrors 46X and 46Y, respectively, and return to the positions of the beam splitters 44 and 45. The mirror reflection optical path length of these laser lights 41X and 41Y is detected by an optical interference detector (not shown).
The relative position of the photosensitive material 1 in the horizontal plane with respect to the image is measured.

Although not shown, the entire photosensitive material feeding mechanism 20 is housed in a light-shielding hood that can be freely opened and closed.

FIG. 2 is a diagram showing the basic principle of drawing in the drawing system 100. Two laser beams B _a and B _{b, which} are periodically deflected in the (± X) direction, are emitted from the drawing head 33.
Irradiated on. Both of these laser beams B _a and B _b are modulated by a predetermined image signal. And
When exposure with the laser beams B _a and B _{b is performed} while moving the photosensitive material 1 in the (−Y) direction, for example, drawing is performed along the arrangement of the scanning lines L extending in the (± X) direction. Since this scanning optical system 200 is a multi-beam scanning system,
The exposure scanning is performed according to the principle described in FIG. However, as described later, the laser beams B _a and B
The spot size of _b and the pixel pitch can be changed independently. Further, the inclination of the scanning line L does not occur due to the reason described later. The drawing area 2 of the photosensitive material 1 is conceptually divided into parallel strips 2a, 2b, ... And the drawing is performed for each strip 2a, 2b ,.

FIG. 3 is a diagram showing the relative movement between the photosensitive material 1 and the drawing head 33 when drawing is performed on the photosensitive material 1 using the drawing system 100. However, the virtual line Y ₀ indicates the position of the movement path of the drawing head 33 in the (± X) direction. First, as shown in FIG. 3A, the photosensitive material 1 moves in the Y direction, and the drawing head
33 comes to the origin position near the lower left corner of the photosensitive material 1.

With the start of drawing, the photosensitive material 1 is sent in the (-Y) direction (FIG. 3B). Accordingly, the drawing progresses in the Y direction for the first strip, and when the photosensitive material 1 is completely fed in the (-Y) direction, the state shown in FIG. 3C is obtained.
Next, the drawing head 33 moves by a predetermined distance ΔX in the X direction (FIG. 3D). This distance ΔX is a distance equal to the mutual arrangement interval between the strips.

For the drawing of the second strip, the photosensitive material 1 is set to Y
Is carried out while feeding in the direction (FIG. 3 (e)). And
After the drawing of the second strip is completed as shown in FIG. 3 (f), the reciprocating scanning described above is repeated. As a result, as shown in FIG. 3 (g), the drawing in the drawing area progresses sequentially, and finally, a desired image is recorded in the drawing area.

(A-2) Electrical Configuration FIG. 4 is a schematic block diagram showing the electrical configuration of the drawing system 100. In the graphic input device 60 including a microcomputer and its peripheral devices, vector data expressing the outline of a desired graphic is generated. This vector data is split vector data S _V becomes divided into each strip is given to the drawing control unit 70.

Marking control device 70, on the basis of the split vector data S _V, to generate a sequential raster data scan line. Then, the raster data is output to the AOM driver 71 as ON / OFF modulation signal S _M. The AOM driver 71 uses this modulated signal S _M
It is converted into AOM drive signal S _MD. Further, a deflection signal _SD for deflecting the drawing laser light is generated, and this is the AOD
It is converted into AOD drive signal S _DD by the driver 72. These drive signals S _MD and S _DD are provided by AOM (acousto-optic modulator) 207 and AO provided in the scanning optical system 200.
D (acousto-optical deflector) 213. In addition,
Corresponding to the scanning optical system 200 being a multi-beam scanning system, the AOM 207 has two AOMs 207a and 207b (not shown in FIG. 4), and each of the signals S _M and S _MD is also included. Contains two ingredients.

On the other hand, the drawing control device 70 sets the scanning optical system 200 to (± X)
With respect to the motor 34 for moving the photosensitive material table 21 in the (± Y) direction.
The motor drive signals M _X and M _Y are supplied respectively. Also,
Position signals S _X and S _Y expressing the position of the photosensitive material table 21 in the XY direction are input to the drawing control device 70 from the laser length measuring device 50 described in relation to the laser oscillator 40 and the like in FIG. You. The drawing control device 70 synchronizes with these position signals S _X and S _Y
The modulation signal _SM and the deflection signal _SD are generated.

B. Details of Scanning Optical System 200 (B-1) Laser Generation and Modulation FIG. 5 is a perspective view showing the internal structure of the scanning optical system 200. Single laser beam LB ₀ emitted from the Ar ⁺ laser oscillator 201 is given to the light amount correction AOM202. This AOM20
When the beam spot diameter on the photosensitive material 1 is changed, 2 corrects the light quantity of the laser beam so that the optimum exposure state can always be obtained. The correction amount may be experimentally obtained in advance according to the characteristics of the photosensitive material 1, and one correction amount is set for each of various combinations of the spot diameter and the pixel pitch. Generally, in order to make the light amount per unit area substantially constant, for example, a large pot diameter is exposed with a relatively large light amount to ensure the exposure.

The laser beam LB ₀ emitted from the AOM 202 is reflected by the mirror 203 and then split into two laser beams LB _a and LB _b by the beam splitter 204. Of these, the first
Beam LB _a is reflected by the mirror 205, and then the condenser lens 20
It is given to AOM207a via 6a. AOM 207a responds to the first component of AOM drive signal S _MD (Fig. 4) by beam LB ₁
ON / OFF modulation. Then, the modulated beam B ₁ is collimated by the collimator 208a and given to the multi-beam adjuster 300 described later.

On the other hand, the second beam LB _b generated by the beam splitter 204 is provided to AOM207b through the condenser lens 206 b. AOM207b is ON / OFF modulation of the beam LB _b in response to a second component of the AOM drive signal S _MD. Then, the modulated beam B ₂ is collimated by the collimator 208b and given to the multi-beam adjuster 300 via the mirror 209. In addition, the two beams B ₁ , which are incident on the multi-beam adjuster 300,
B ₂ is proceeding at right angles to each other.

Note that these two modulated beams are not limited to this embodiment, and may be obtained by other commonly used methods such as a method of obtaining each from another laser light source (including a semiconductor laser). Furthermore, since the modulation by the semiconductor laser can be performed by the semiconductor laser itself, it is not always necessary to provide a separate modulating means.

(B-2) Principle of Beam Direction Change FIG. 6 is an explanatory view of the principle of beam direction change, which is the premise of the configuration of the multi-beam adjuster 300. The multi-beam adjuster 300 has a beam redirecting element 301, as shown in FIG. This beam redirecting element 301 has the same structure as the beam splitter, and has a half mirror surface.
Has 302. A part of the first beam B ₁ passes through the half mirror surface 302 and becomes _a straight beam B _{a in} FIG. Further, a part of the second beam B ₂ is reflected by the half mirror surface 302 and becomes a reflected beam B _b . By rotationally displacing the element 301 according to a rule described later, the two beams B _a and B _b intersect each other at a predetermined point P _C on the rear side of the element 301. An AOD 213 for periodically deflecting these two beams B _a , B _b is arranged at this intersection P _C ,
The beams B _a and B _b after being deflected by are converted into a parallel beam group by the scan lens 216. However, the distance between the intersection P _C and the scan lens 216 is the same as the focal length f of the scan lens 216.

The reason why the beams B _a and B _b are thus converted into the intersecting beams that intersect at the intersection P _C is as follows. First, sensitive material 1
In order to arbitrarily change the pixel pitch on the surface of the photosensitive material 1, it is necessary to change the mutual distance l between the two beam spots on the surface of the photosensitive material 1, as described with reference to FIG. For that purpose, the scanning optical system 200
In the above, a mechanism for changing the mutual distance between the beams B _a and B _b is required.

However, if the beams B _a and B _b are immediately converted into the parallel beam group and the structure in which the mutual distance between them is changed is added, a problem occurs. That is, if the two beams are simply made parallel, these beams after passing through the scan lens 216 will be imaged at one point and the pixel pitch cannot be set to a required value. Therefore, it is necessary to make an angle between the two beams, but at this time, the two beams intersect at the intersection Pc for the following reason. The first is that the diameter of the incident side aperture of the AOD 213 is relatively small because the crystal pieces forming the AOD element are not so large. The second fact is that in order to sufficiently narrow the beam on the photosensitive material 1, the beams B ₁ , B
The fact is that the beam diameter of ₂ cannot be made too small. Therefore, considering this second fact, the beams B ₁ , B
Setting the diameter of ₂ relatively large and simply giving an angle between these beams B ₁ and B ₂ causes the beam to move according to the first fact as the intersection gets farther from the center position of the AOD.
Both B ₁ and B ₂ cannot enter AOD 213. Also AOD
Even when using a polygon mirror or the like instead of 213,
Since the height of the mirror surface of the polygon mirror is not so large, it is not easy to configure the parallel beam group to be always reflected by the mirror surface.

Therefore, in this embodiment, the beams B ₁ and B ₂ are crossed with each other.
_By converting to _a , B _b and changing the intersection angle θ,
It is intended to change the mutual distance l ₀ (and thus the spot mutual distance 1 on the photosensitive material 1) when the deflected beams B _a and B _b are converted into parallel beam groups by the scan lens 216. In this case, the AOD 213 is arranged at the intersection P _C for the reason described above, and the beams B _a and B _b are surely A if the intersection angle θ changes.
It can be incident on OD213. However, intersection P _C and AOD213
The center point and completely not necessary to match, may be incident side aperture AOD213 coincides with the intersection P _C. When a polygon mirror or a galvano mirror is used instead of the AOD213, those mirror surfaces are arranged at the intersection P _C. Also, set the focus position of the scan lens 216 to the intersection P _C
This is because the parallel beam group is always obtained on the rear side of the scan lens 216 even if the crossing angle θ changes.

Then, two beams B _a, while satisfying the condition that B _b always intersect at an intersection P _C, analyzed for rules for changing the crossing angle θ arbitrarily. In this embodiment, the predetermined point C _R
A rotational displacement is applied to the element 301 about the center, and the crossing angle θ is changed accordingly. In this case, when the distance between the reference position of the beam redirecting element 301 (that is, the position of the element 301 when the half mirror surface 302 exists at the position 302a in FIG. 7) and the rotation center C _R is A, the element 301 It is necessary to determine how the distance A should be determined with respect to the optical path length a between the reference position (1) and the intersection P _C.

FIG. 7 is a diagram for this analysis, in which the element 301 (not shown) rotates about the rotation center C _{R by} the angle β, and in that state, the beams B _a and B _b have the angle θ at the intersection P _C. It is the figure which assumed that it made and crossed. However, auxiliary lines and the like are defined as follows.

Reflection points P _R ... beam B2 on the half mirror surface 302, F _H ... through the point P _R, a line parallel to the optical axis of the beam B _1, the normal line of the F _N ... half mirror surface 302, F ₄₅ ... beam A line that makes an angle of π / 4 with the incident direction of B ₂ , α ... an angle that the incident direction of beam B ₂ makes with a straight line F _N , h ... the height of point P _R seen from the optical axis of beam B ₁ .

In this case, the angle formed between the straight line F _N and F _H (α-θ), and the also the angle between the traveling direction of the straight line F _H and the beam B ₂ π / ₂
Therefore, the equation (5) is established.

(Α−θ) + α = π / 2 (5) Since the angle between the straight line F ₄₅ and F _H is π / 4,
Formula (6) is materialized.

(Α−θ) + β = π / 4 (6) Equation (7) is obtained by eliminating α from Equations (5) and (6).

β = θ / 2 (7) On the other hand, the following expressions (8) and (9) are established.

tan β = h / A (8) tan θ = h / a (9) Therefore, from equations (7) and (8), Then, by substituting the relational expression obtained from the equation (9): cos θ = cos [tan ⁻¹ (h / a)] (11) into the equation (10), Is obtained.

Equation (12) is an equation showing the dependency of the distance A on a, and the values of the quantities a and h are determined as, for example, a = 300 mm (13) h = 0.04 mm (14). Therefore, h is a high-order minute quantity with respect to a, and equation (13) can be approximated to A2a (15) with very high accuracy. Therefore, in this embodiment, the rotation center is a point separated from the reference position 302a by twice the optical path length a between the reference position 302a of the half mirror surface 302 and the position of the AOD 213. For this reason, the multi-beam adjuster 300 of FIG. 4 is configured as described later in order to give such a rotational displacement to the element 301.

By the way, since the element 301 does not translate upward in FIG. 7, but rotates around the rotation center C _R , the reflection point P _R when the intersection angle θ is not 0 is the center of the half mirror surface 301. It is out of alignment. FIG. 8 is an exaggerated drawing of this situation. When the element 301 is virtually translated upward and rotated around its center (solid line), 2
As indicated by the dotted chain line, the case where it is rotated around the rotation center C _R (broken line) is shown. Further, FIG. 9 is an enlarged view of the vicinity of the reflection point P _R of FIG.
Definitions of auxiliary lines in the figure are as follows.

J: Center point of the half mirror surface 302 for the element 301 drawn by a solid line.

K: The center point of the half mirror surface 302 for the element 301 drawn by the broken line.

P _CE (Figure 8) ... the position of the actual beam intersection, by the deviation, are displaced by Δa from the ideal intersection P _C.

F _L The optical path of the beam B _b when the element 301 exists at the position indicated by the solid line.

F _B : Optical path of the beam B _b when the element 301 exists at the position indicated by the broken line.

[Delta] H ... 2 two optical paths F _L, vertical distance, perpendicular foot that beat from T ... point K to the straight line P _R J of F _B.

e, g, ... Distances shown in FIG.

Of these, the distance g is as follows from FIG. 8: g = 2a−2a cosβ = 2a (1-cosβ) (16) Further, ∠P _R KT becomes ∠P _R KT = π / 4 + β (17) with the β rotation of the half mirror surface 302. Therefore, Is obtained.

 Further, from FIG. 8, Δa = ΔH / tan (2β) (19).

Since the angle beta is to be a relatively small value, the approximate expression: tanββ ... (20) tan ( 2β) 2β ... (21) cosβ1-β 2/2 ... (22) is established. Therefore, using equations (18) to (22), Δaaβ (1 + β ² ) / [2 (1-β)] (23), and leaving only the main term for β, Δaaβ / 2 (24) Becomes Specifically, if a = 300 mm (25) h = 0.04 mm (26), then βtan β = h / (2a) = (2/3) × 10 ^-4 (27), so (24 ), (25), (27), Δa10 ^-2 (28), and this deviation Δa is sufficiently small. That is, the reflection point
The error caused by the deviation of P _R from the center of the half mirror surface 301 can be substantially ignored. In other words, A =
Element 301 around the center of rotation C _R determined by the relationship of 2a
It can be considered that the beams B _a and B _b always intersect at the point P _{C when} is rotated.

(B-3) Configuration of Multi-Beam Adjuster 300 FIG. 10 is a perspective view of the multi-beam adjuster 300 constructed according to the above principle. Further, FIG. 11 is a conceptual side view thereof. In FIG. 10, the multi-beam adjuster 300 has a beam redirecting element 301 and an integral notch link mechanism 303 that is coupled to the element 301 and imparts rotational displacement thereto. The cutout link mechanism 303 is obtained by processing an elastic body such as an integral metal block plate, and the outer frame members 311 to 314 arranged in a rectangle form a fixing portion. Arm members 315 and 316 extend horizontally from a member 314 standing upright on the right side of FIG. 10, and cutout portions 321 and 322 form boundaries between them. The left ends of these arm members 315 and 316 are connected to the center member 317 via cutouts 323 and 324.

A cutout portion 325 is provided adjacent to the cutout portion 324 on the lower left side, and another arm member 318 extends rightward from the cutout portion 325. The arm member 318 is connected to the outer frame member 311 via the notch 326. The right end portion of the arm member 318 is connected to the piezo element 330 via the cutout portion 327. Further, a support member 331 is attached to the right outer frame member 314, and by operating the micrometer 332 supported by this support member 331, the piezo element 330 is displaced in the vertical direction.

The beam redirecting element 301 is fixed to the center member 317. The first beam B ₁ incident from the left side of FIG. 10 is a through hole provided in the outer frame member 312 and the center member 317.
Reaches the element 301 through 341, components transmitted through the half mirror surface 302, the beam B _a through the through hole 342 provided in the outer frame member 314 and the support member 331. Further, the second beam B ₂ given from above reaches the half mirror surface 302 through the through holes 343 provided in the outer frame member 313 and the arm member 315. Of this beam B ₂ , the half mirror surface 302
The component reflected by becomes a beam B _b through the through hole 342.

The cutout link mechanism 303 is formed of an elastic body, but portions other than the cutout portions 321 to 327 have a relatively large cross section, and only the cutout portions 321 to 327 cause elastic bending. Therefore, this notch link mechanism 330
The cutouts 321-327 as link nodes, and members 315-3
A link with 18 as an arm is formed.

As shown in FIG. 11, there is a height difference of Δu between the cutouts 321 and 323. Similarly, cutouts 322 and 324
There is also a height difference Δu between and. Therefore, in FIG. 12 that schematically represents the cutout link mechanism 303, the extension lines of the arm members 315 and 316 intersect at a point C _A. Further, the members 315, 316, 317 form a four-bar linkage mechanism 340, and the lever having the notch 326 as a fulcrum
341 is connected to the four-bar linkage 340. And
The length of each member is set so that the displacement of the beam redirecting element 301 by this link mechanism can be almost ignored compared to the distance 2a. Therefore, the four-bar linkage 340
When a link motion is applied to the center member 317 (and therefore the element 301), the center member 317 rotates about the point C _A as an instantaneous center of rotation. Therefore, the distance between the element 301 and the point C _A is
If the size of each part of the notch link mechanism 303 is determined so as to be a, it is possible to apply the rotational displacement corresponding to FIG. 6 to the element 301 with the point C _A as the rotation center C _R of FIG. it can.

On the other hand, the lever 341 in FIG. 12 is driven by the piezo element 330. For example, when the piezoelectric element 330 is stretched and a pressing force FP is applied to the cutout portion 327, a pushup force FL is generated in the cutout portion 325 existing at the left end of the lever 341, and as a result, a rotational force is applied to the center member 317. FC is added. And, thereby, the element 301 is rotationally displaced around the center of rotation C _A = C _R. The micrometer 332 in FIG. 10 is for rough adjustment in determining the initial position of the element 301.

The extension amount ΔL _P (not shown) of the piezo element 330 and the crossing angle θ
The relationship with (Fig. 6) can be known in advance by analysis based on the finite element method, for example. The notch link mechanism 300 adopted in the embodiment has a size such that the following expression (29) is satisfied.

θ = 2β = 3.0ΔL _P (29) Therefore, the extension amount ΔL to obtain the desired crossing angle θ
_P is given to the piezo element 330 according to the equation (29).

(B-4) Deflection of Beams B _a and B _b Returning to FIG.
300 obtained in beam B _a, B _b, after being reflected by the mirror 210 intersect each other at the intersection P _C in AOD213. However, in FIG. 5, this intersecting state is not shown for convenience of illustration. The distance a defined in FIG. 6 corresponds to the optical path length from the element 301 in FIG. 5 to the AOD 213. Furthermore, in the configuration of FIG.
At 210, the traveling directions of the beams B _a and B _b change, but
The center of rotation C _R in the figure exists at the point where the straight line connecting the multi-beam adjuster 300 and the mirror 210 in FIG. 5 is extended as it is (not shown in FIG. 5).

AOD213 periodically deflecting the two beams B _a, a B _b the deflection direction DF _0. The deflected beams B _a and B _b are scanned by the scan lens 216.
In this scan lens 216, mutually parallel beams having a mutual interval according to the crossing angle θ are formed. And
The beams B _a and B _b thus collimated are reflected by the mirror 217 and enter the drawing head 33.

The beams B _a and B obtained by the multi-beam adjuster 300
_b can change its luminous flux appropriately by a commonly used beam expander, but in this case, the rotation center C _R , and thus AO
Decide the position of D213.

(B-5) Deflection Direction Adjuster 400 The deflection direction adjuster 400 is arranged at the first stage of the drawing head 33. The deflection direction adjuster 400 includes a Pechan prism 401 and a prism rotation mechanism 402. As is well known, the Pechan prism 401 is an “image rotation prism”.
When the Pechan prism 401 is rotated around its central axis, the image obtained through the Pechan prism 401 rotates by an angle twice the rotation angle of the prism 401. Therefore, as shown in FIG. 13, when the Pechan prism 401 is rotated by the angle φ, the deflection direction DF ₀ of the beams B _a and B _b is rotated by the angle 2φ, and the deflection direction on the rear side of the Pechan prism 401 is Become DF.

FIG. 14 is a perspective view showing a specific example of the deflection direction adjuster 400, and FIG. 15 is a front view thereof. This deflection direction adjuster
In 400, a Pechan prism 401 as a deflection direction rotating means and a prism rotating mechanism (rotation angle that freely rotates the deflecting directions of the beams B _a , B _b by rotating the Pechan prism 401 itself around its central axis. Change means) 402 and are mutually connected.

The prism rotation mechanism 402 projects leaf springs 404 to 407 radially inward from four corners of a rectangular outer frame body 403, and supports the inner frame body 408 by the leaf springs 404 to 407. A Pechan prism 401 is fixed inside the inner frame body 408, and a mirror 409 is provided on the upper surface of the Pechan prism 408.
Is installed. In addition, two piezo elements 410 and 411 are horizontally inserted between the inner frame body 408 and the outer frame body 403. Elastic members having notches 412 to 415 (FIG. 15) are provided at both ends of each of the two piezoelectric elements 410 and 411. The mounting heights of the piezo elements 410 and 411 are different from each other, and as shown in FIG. 15, they are deviated by the same distance ΔZ from the height of the center point Z ₀ of the Pechan prism 401, respectively. As a result, when the piezoelectric elements 410 and 411 are expanded by the same amount,
A couple acts on the Pechan prism 401 by the extension force, and the Pechan prism 401 rotates around the center point Z ₀ . Further, when the drive signals to the piezo elements 410 and 411 are deactivated, the elastic force of the leaf springs 404 to 407 causes the Pechan prism 401 to return to the initial position (angle).

A semiconductor laser oscillator 416 and a beam splitter 417 are attached to the upper side of the outer frame 402. The laser beam L _S (FIG. 15) emitted from the laser oscillator 416 reaches the mirror 409 via the through hole 418 after being reflected by the beam splitter 417. Laser beam reflected by mirror 409
L _S faces upwards, beam splitter 417 and through hole 419
Through the PSD (Positi) that is fixed above the outer frame 403.
on Sensing Device) 420. Therefore, when the Pechan prism 401 is rotated by driving the piezo elements 410 and 411, the rotation angle φ (not shown in FIGS. 14 and 15) is detected as the positional displacement of the light spot on the PSD 420.

FIG. 16 is a control block diagram of the deflection direction adjuster 400. A desired pixel pitch P value is input to the drawing control device 70. The drawing control device 70 calculates and obtains the compensation angle δ for compensating the inclination of the scanning line based on the pixel pitch P. That is, when the beam deflection speed corresponding to the pixel pitch P is V _X and the photosensitive material feed speed in the Y direction is V _Y , the compensation angle δ is determined as δ (V _Y / V _X ) (30) . There is a relationship of V _X τ _X = P (31) V _Y τ _Y = 2P (32) between the velocities V _X , V _Y and the pixel pitch P, and τ _X and τ _Y are respectively , X-direction and Y-direction are clock cycles of the scanning clock. When changing the pixel pitch P, for example, τ _X and V _Y
And are changed. Further, the drawing control device 70 supplies a strip instruction signal S _C indicating whether the strip currently being drawn is an odd-numbered strip or an even-numbered strip.

In the command value generation circuit 440, the Pechan prism rotation angle φ ₀ is calculated from the compensation angle δ. According to the principle of rotation in the deflection direction described with reference to FIG. 13, this angle φ ₀ is given by φ ₀ = γ (δ / 2) (33). However, the coefficient γ is (+1) when the strip being drawn is an odd-numbered strip and (−1) when it is an even-numbered strip.

On the other hand, as is well known, the PSD 420 outputs a pair of detection signals S ₁ , S ₂ (sixteenth signal) from a pair of electrodes provided therein.
(Fig.) Is output. The known PSD signal processing circuit 430 calculates and obtains the light spot displacement Δt on the detection surface of the PSD 420 based on these detection signals S ₁ and S ₂ . Further, this light spot displacement Δt is divided by 2 l _P (l _P is the distance between the mirror 409 and PSD 420) to obtain the actual rotation angle φ of the Pechan prism 401. The coefficient “2” is present in this division because the deflection angle of the detection beam L _S is twice the rotation angle φ of the prism 401.

The value of this actual rotation angle φ and the value of the command rotation angle φ ₀ are PI
It is taken into the D control circuit 442. The PID control circuit 442 generates a proportional signal, an integral signal, and a differential signal for these deviations (φ ₀ −φ), and the PID control signal as a combination thereof. Is output to the piezo driver 443. Then, the piezo driver 443 generates the piezo element drive signal _SPZ , and thereby expands and contracts the piezo elements 410 and 411 by the same amount.

By performing the closed loop control as described above, the rotation angle φ of the Pechan prism 401 becomes equal to the command value φ _0, and further, the influence of the hysteresis of the piezo element is excluded, and as a result, the beam B _a , B
The deflection direction of _b also rotates by the angle δ (= 2φ ₀ ). However, in controlling the deflection direction adjuster 400, open loop control may be performed. However, since there is hysteresis in the piezo element, when changing the rotation angle φ, once set the piezo element drive signal S _PZ to “0”,
It is desirable to return the piezoelectric elements 410 and 411 to the origin.

(B-6) Variable condensing mechanism 500 Returning to FIG. 5 again, the beams B _a and B _b after rotation in the deflection direction
Is given to the variable focusing mechanism 500 via the relay lens 218. FIG. 17 is a diagram showing the function of the relay lens 218,
For convenience, only the position of the Pechan prism 401 is shown, and the mirror 217 in FIG. 5 is omitted. As shown in FIG. 17, the beams B _a and B _b after having exited the scan lens 216 are beams parallel to each other, and the beams B _a and
Each of B _b is a convergent light flux. Then, each of the convergence point F _a, Pechan prism 218 to the position of the F _b is arranged. Note that consideration is given to the optical path length caused by Pechan prism 218, if the F _a, not limited to F _b, the position after the deflection, can be appropriately arranged. Relay lens 218
Thus, the beams B _a and B _b are made to cross light, and the beams B _a and B _b are condensed on the photosensitive material 1 by the objective lens 501 (or 502-504) described later. In this way, the scan lens 216
The reason why the two-stage light collection is performed by the relay lens 218 and the relay lens 218 is that the degree of freedom in design is increased as compared with the case where only a single scan lens 216 collects light.

On the other hand, in the variable condensing mechanism 500 of FIG. 5, a plurality of objective lenses 501 to 504 having different focal lengths are held by a perforated disk-shaped lens holder 505. The outer peripheral surface of the lens holder 505 is a gear surface, and this gear surface and the gear surface of the drive gear 508 mesh with each other. The drive gear 508 is rotationally driven by the drive motor 507, which causes the lens holder 505 to rotate about the axis 506.

One objective lens (for example, 501) is selected in the turret type lens holder 505, and the objective lens 501 is rotationally moved in the optical paths of the beams B _a and B _b .
Then, the beams B _a and B _b are reduced and projected onto the photosensitive material 1 at _a reduction ratio specific to the objective lens 501. When another objective lens 502 is selected and the beams B _a and B _b are condensed by the objective lens 502, the size of the spots SP _a and SP _b (FIG. 17) of the beams B _a and B _b on the photosensitive material 1 is determined. The mutual distance l changes. Therefore, in this embodiment, the sizes of the spots SP _a and SP _b are the objective lenses 501 to 50.
It can be changed in 4 ways according to the degree of freedom of selection from among the 4.

The above "scan lens 217 and relay lens 218"
Alternatively, “the relay lens and the objective lens may each be configured by an optical system having a variable focal length such as a zoom lens.

(B-7) Summary of Examples In the above-described configuration, the size of the spots SP _a and SP _b and the mutual distance l are changed by changing the selection of the objective lens in the variable focusing mechanism 500, for example, size: d ₁ → d ₂ If the distance: l ₁ → l ₂ is changed and the crossing angle θ is changed so that the distance l ₂ is returned to l ₁ by the multi-beam adjuster 300, only the spot size can be changed as a result.
Further, if only the intersection angle θ is changed without changing the objective lens, only the distance 1 can be changed, whereby the pixel pitch can be changed with the spot size fixed.

Further, when the photosensitive material 1 is fed in the (-Y) direction as shown in FIG. 18 (a), the deflection direction adjusting means 400 changes the beam deflection direction by an angle δ measured downward to the right from the X axis. Then, when viewed on the surface of the photosensitive material 1, the inclination of the scanning line due to the feeding of the photosensitive material 1 is compensated, and
Scanning lines parallel to the X direction are obtained as shown in FIG.
When the photosensitive material 1 is fed in the (+ Y) direction (Fig. 18 (c))
If the direction of the compensation angle δ is reversed, the scanning line of FIG. 18 (b) can be obtained. The magnitude of the compensation angle δ is also changed every time the scanning speed is changed along with the change of the pixel pitch.

C. Modified Example (C-1) Use of Three or More Beams The present invention is not limited to the case of using two laser beams, but can be applied to an apparatus that performs drawing using three or more laser beams. . For example, when converting the _three beams B _{1 to} B ₃ shown in FIG. 19A into the cross beams B _{a to} B _c , two beam redirecting elements (not shown) having half mirror surfaces 302 _A and 302 _B , respectively. ), The traveling directions of the beams B ₂ and B ₃ are changed. Then, two mechanisms similar to the cutout link mechanism 330 of FIG. 10 are prepared, and the half mirror surfaces 302 _A and 302 _B are individually rotationally displaced. However, since the distances between the half mirror surfaces 302 _A and 302 _B and the intersection P _C are different from each other, the distances to the rotation centers are different values. By doing this, the intersection angle θ ₁₂ ,
Each of θ ₁₃ can be changed arbitrarily.

When three or more beams are used, the spot intervals on the photosensitive material 1 do not necessarily have to be the same. Generally, when using a beam of the m (m ≧ 2), the mutual distance l _12, l ₁₃ in their photosensitive material on 1, ..., l _{1 m} (19
B) is selected so as to satisfy l _1j = [mI _j + (j-1)] P (j = 2 to m, I _j is a natural number) (33) By moving the photosensitive material 1 by a distance m times the pixel pitch P, it is possible to perform drawing covering the entire drawing area. This corresponds to the rule that the array of scanning lines is divided into m lines, and the i-th (1 ≦ i ≦ m) scanning line is scanned with the i-th beam in each section. For this reason,
The spot-to-spot distance may be arbitrarily changed under the condition of the above formula (33).

(C-2) Modification of Multi-Beam Adjuster 300 The multi-beam adjuster 300 may be configured to give rotational displacement to the beam redirecting element 301. For this reason,
As shown in FIG. 20, the element 301 may be fixed on the stage 370, and the stage 370 may be supported by the piezo elements 371 and 372 via cutout links. In this case, by making the expansion amounts of the piezo elements 71 and 372 different from each other, the element 301 is rotationally displaced in the θ _a direction in the drawing.

Further, as shown in FIG. 21, if a four-joint link mechanism in which arms 381 to 383 are sequentially connected is used, the element 301 is rotationally displaced about the intersection P _R of the extension lines of the arms 381 and 383 as the center of rotation.

(C-3) Deformation of the deflection direction adjuster 400 As the image rotation prism, there is a Dove prism 450 (FIG. 22) in addition to the Pechan prism. Therefore, the deflection direction DF may be changed by rotating the Dove prism 450 around its central axis using the prism rotating mechanism 402 shown in FIG. However, astigmatic aberration occurs when passing the convergent beam through the Dove prism 450,
The deflection direction adjuster using the Dove prism 450 is preferably provided between the beam expander 214 and the scan lens 216 in FIG. When the deflection direction adjuster using the Dove prism 450 is arranged at the rear stage of the scan lens 216, the astigmatism correction lens 451 is provided at the front stage side of the scan lens 216 as shown in FIG. In the case of the Pechan prism 401, since such astigmatism does not occur, it can be installed at any position in the section from the AOD 213 to the variable condensing mechanism 500.

The Dove prism 450 is equivalent to the three mirrors 452 to 454 as shown in FIG. Therefore, these three mirrors 452 to 454 may be rotated without changing their relative positions.

To change the deflection direction of the laser beams B _a and B _b , use the second
A mirror 455 may be used as shown in FIG. Mirror 455
When is rotated in the φ _m direction, the deflection direction DF also rotates. However, since the reflection positions of the beams B _a and B _b are displaced with the rotation of the mirror 455, the optical axes of the beams B _a and B _b after being reflected by the mirror 455 are deviated. For this reason, Pechan Prism 4
It is preferable to use 01 or Dove prism 450.

FIG. 26 shows another mechanism 460 for rotating the Pechan prism 401. This mechanism 460 uses a disc 462 having a window 461, and the Pechan prism 401 is housed in the window 461. The disc 462 is rotatably mounted on the base 463, and is rotated around its central axis by the expansion and contraction of the piezo element 463. As a result, Pechan Prism 40
1 also rotates in the φ direction.

In still another mechanism 470 shown in FIG. 27, a four-node cutout link mechanism 471 is driven by a piezo element 472. However, the extension lines of the two arm members 473 and 474 forming the hypotenuse intersect at the center point Z ₀ of the Pechan prism 401. According to this mechanism 470, the Pechan prism 401 rotates around its center point Z _{0 as} the piezo element 472 expands and contracts.

FIG. 28 shows another example of the mechanism for rotating the Dove prism 450. The dove prism 450 is fixed on the stage 481, and the stage 481 is supported by the two piezo elements 482 and 483.
The Dove prism 450 can be rotated by expanding and contracting the piezo elements 482 and 483 in opposite directions. The mechanisms shown in FIGS. 26 to 28 can be applied to both the Pechan prism 401 and the Dove prism 450.

FIG. 29 shows an example of a mechanism for rotating the deflection direction using the mirror 455 as shown in FIG. A stage 491 having a triangular prism shape is supported by piezo elements 492 and 493, and the piezo elements 492 and 493 are expanded and contracted in opposite directions, whereby the mirror 455 rotates.

(C-4) Other Modifications It is preferable that the inclination of the scanning line due to the change of the pixel pitch is compensated by using the deflection direction adjuster 400 as described above. However, when the feed speed V _Y of the photosensitive material 1 is relatively small and the drawing scanning is one-way scanning, it may be practical without the tilt compensation. Therefore, a configuration in which the deflection direction adjuster 400 is omitted is also included in the scope of the present invention.

〔The invention's effect〕

As described above, according to the first configuration of the present invention, the mutual distance between the plurality of light beams can be arbitrarily changed by changing the crossing angle of the plurality of light beams in the deflecting means. The pixel pitch above can be changed independently of the spot size. Moreover, according to this configuration, the intersection angle can be changed while always intersecting the light beams at a predetermined point only by rotationally displacing the beam direction changing means by the intersection angle changing means, and the pixel can be easily configured. You can change the pitch. Further, since the plurality of light beams always intersect at the deflecting means, the light beams do not deviate from the changing means when changing the mutual distance of the light beams.

Further, according to the second configuration, since the condensing unit is configured by using the variable focal length optical system, the spot size is also independently set by the combination of the condensing unit and the first configuration. It can be changed.

Further, according to the third configuration, even when the tilt angle of the scanning line changes with the change of the pixel pitch, the tilt can be always compensated. In the case of reciprocal scanning, the inclination of the scanning line can be compensated in both reciprocating operations, so that it is possible to prevent distortion of the image obtained on the photosensitive material in reciprocal scanning for ensuring high-speed drawing.

[Brief description of drawings]

FIG. 1 is a perspective view of a drawing system 100 incorporating a scanning optical system 200 according to an embodiment of the present invention, and FIGS. 2 and 3 are explanatory views of a scanning principle of a photosensitive material 1 in the drawing system 100. 4, FIG. 4 is a block diagram showing an outline of an electrical configuration of the drawing system 100, FIG. 5 is a configuration diagram of the scanning optical system 200, and FIGS. 6 to 9 are diagrams showing rotation of the beam redirecting element 301. FIGS. 10, 11, and 12 are perspective views of the multi-beam adjuster 300, a side view and a schematic view of the mechanism, and FIG. 13 is an explanatory view of the Pechan prism 401, respectively. 14 and 15 are respectively a perspective view and a front view of the deflection direction adjuster 400, FIG. 16 is a control block diagram of the deflection direction adjuster 400, and FIG. 17 is a laser beam inside the scanning optical system 200. 18 is an explanatory view of the optical path of FIG. 18, FIG. 18 is an explanatory view of scanning line inclination compensation, and FIG. 19A is FIG. 19B is an explanatory view of changing a crossing angle when three laser beams are used, FIG. 19B is an explanatory view of a spot interval when an arbitrary number of laser beams are used, and FIGS. 20 and 21 are multi-beams. Explanatory drawing of a modified example of the adjuster, FIG. 22 is an explanatory view of the Dove prism 450, FIGS. 23 to 29 are explanatory views of a modified example of the deflection direction adjuster, and FIG. 30 is drawing by a multi-beam. And FIGS. 31A to 31C are explanatory diagrams of the inclination of the scanning line. 1 ... sensitive material, 2 ... drawing area, 2a-2z ... strip, 33 ... drawing head, 100 ... drawing system, 200 ... scanning optical system, 207a, 207b ... AOM, 213 ... AOD, 300 …… Multi-beam adjuster, 301 …… Beam direction changing element, 302 …… Half mirror surface, 303 …… Notch link mechanism, 400 …… Deflection direction adjuster, 401 …… Pechan prism, 402 …… Prism rotation mechanism, 500 ...... variable condensing mechanism, 501 to 504 ...... objective lens, B _a, B _b ...... laser beam, d ...... spot size, P ...... pixel pitch, l ...... spot distance, DF ...... Deflection direction

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takumi Yoshida, Teranouchi, Horikawa-dori, Kamigyo-ku, Kyoto Prefecture 1 at 1 Tenjin Kitamachi 4-chome, Horikawa-dori Teranouchi, Kamigyo-ku, Kyoto, Kyoto Prefecture (1) Within Dainippon Screen Manufacturing Co., Ltd. (56) References 42515 (JP, U)

Claims (3)

(57) [Claims] 1. A beam group consisting of a plurality of modulated light beams is periodically deflected, and the beam is deflected to scan a photosensitive material, and the photosensitive material and the beam group are relatively moved. A scanning optical system used for sequentially exposing the drawing areas on the photosensitive material by moving the plurality of modulated light beams at predetermined points. Beam redirecting means for redirecting to a first light beam group, and (b) being coupled to the beam redirecting means for rotationally displacing the beam redirecting means so as to provide the first beam at the predetermined point. A crossing angle changing means for changing a crossing angle of the light beam group; and (c) is arranged at the predetermined point to periodically deflect the first light beam group, thereby generating a second light beam group. Deflecting means for: (d) the second Condensing means for condensing each of the light beams belonging to the beam group onto the light-sensitive material, wherein the intersection angle changing means is about twice the distance from the intersection angle changing means to the deflecting means. A scanning optical system, wherein the beam direction changing means is rotationally displaced about a point distant from the intersection angle changing means to the deflecting means side as a rotation center. 2. The scanning optical system according to claim 1, wherein the focusing means comprises a variable focal length optical system. 3. The scanning optical system according to claim 1 or 2, further comprising: (e) the second light beam group which is inserted between the deflecting means and the condensing means. And (f) is coupled to the deflection direction rotation means and rotates the deflection direction rotation means to change the rotation angle of the second light beam group in the deflection direction. Rotation angle changing means for: (g) reciprocating movement means for relatively reciprocating the sensitive material and the beam group in the relative movement direction; (h) the deflection based on the relative movement direction. A scanning optical system comprising: direction control means for controlling the rotation direction of the direction rotation means.