JPS597331A - optical scanning device - Google Patents

Abstract

PURPOSE:To obtain a device which enables exact two-dimensional scanning conforming to the orthogonal coordinate system on an object by providing a reflection means for reflecting a light beam onto the object and an adjustment means for turning said reflection means. CONSTITUTION:A rotating mechanism 160 and stationary parts 18, 20 are all mounted to a stationary plate 22, and when the preceding end part of a micrometer 17 is moved in an arrow 21 direction, a holder 16 turns slightly in an arrow 21 direction similarly around the revolving shaft Cl perpendicular to a photosensitive object (projection plane) 9, by which a reflecting mirror 7 is turned as well, and the angle theta of the laser spot locus reflected by the mirror 7 and scanned horizontally on the object 9 to the x axis is made adjustable. The device which enables the exact two-dimensional scanning conforming to the orthogonal coordinate system on the object is thus realized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical scanning device used in laser beam printers, pattern generators, image reading devices, multicolor printing clothing N, and the like. More details <
(d, the present invention d1 includes means for linearly scanning a light beam in the X direction, and moving means for moving the object to be drawn by this light beam in the X direction intersecting the The present invention relates to an optical scanning device that draws a desired pattern on a surface.

Conventionally, there is an optical scanning device that deflects and scans a laser beam using a rotating polygon mirror or a galvano mirror, focuses it on a minute spot via an fθ lens, and scans a plane line. In this device, scanning along one axis (main scanning) is performed by scanning a laser spot, and scanning along an axis perpendicular to this axis (sub-scanning) is performed using a rotating drum, a one-dimensional moving stage, or the like.

FIG. 1 is an explanatory diagram showing a scanning locus of a laser spot on a photosensitive object (projection surface) scanned by such a conventional scanning device. The scanning trajectory St is not parallel to the X-axis due to the movement of the stage, but is inclined to the X-axis by an angular displacement θ. This inclination angle θV1. If the two-direction perspiration rate of the laser spot is Vx + the moving speed of the stage in the y direction is vy, then li# is finite, although it is small.

Usually, a pattern such as an image is drawn on a Δ・& optical drum.
In the case of the previous arrangement, the inclination angle θ relative to the scanning trajectory In the case of 1, the masks of two types of overlapping patterns are required to match accurately (C) on the front and back sides of the print, and the inclination of the scanning trajectory is 1, the existence of an angle θ, 1゛, that is, the presence of the cypress thread The error in orthogonality is a problem.

Here, the present invention aims to solve these problems and realize an optical scanning device capable of performing accurate two-dimensional scanning according to the plane alignment system.

The device according to the present invention reflects a light beam onto an object, and also includes a reflecting means that is rotatable around the central part of the iNg scanning range of the light beam, and a rotation angle of the reflecting means. The feature is that a means for adjustment is provided.

FIG. 2 is a perspective view of the structure of an example of the apparatus according to the present invention, and FIG. 6 is a plan view showing the main parts of the apparatus shown in FIG. In these figures, 2 is an IH laser light source, 2 is an optical modulator that modulates the laser beam from light source 1 according to a turn signal (writing data), 6 is a beam expander, and 4 is a d-beam expander. 6 is a rotating polygon mirror having several reflective surfaces 5 that causes the laser beam incident thereon to scan linearly in the X direction; 6 is an fθ lens on which the laser beam from the rotating polygon mirror 4 is incident; each of these elements; is the same as that used conventionally.

7 directs the light emitted from the fθ lens 6 to a photosensitive object (projection surface).
It is a reflecting mirror that vertically reflects the laser beam on the laser beam 9, and is configured to be able to rotate around an axis Ct provided at the center of the laser beam in the linear scanning range of the laser beam. Reference numeral 8 denotes a sporatono trajectory scanned on the photoreceptor 9, 10 a moving stage for moving the photoreceptor 9 in the y-axis direction, and 11 a base of this moving stage, on which an I'iv-shaped guide is mounted. groove 14;
7 runt surfaces 15 are provided, and the moving stage 1o
The direction of motion is constrained. 12 rri motor, 16 is coupled to this motor and screwed to the moving stage 1o;
The movable stage 10 is moved at a constant speed in the y nun direction by 191 rotations of the motor 12 using the screws.

16 is a holder that holds the reflecting mirror 7; 16o is a +Ij+ rotation mechanism provided on the holder 16; 17 is a fixing part 18;
When the micrometer is rotated, its tip that is in contact with one end of the holder 16 moves slightly in the direction of the arrow 21. A spring fixed to the 19-piece fixing part 20 pushes one end of the holder 7.

FIG. 4 is a sectional view including the rotation axis Ct of the part holding the reflecting mirror 7. When the tip of the micrometer 17 is moved in the direction of the arrow 21, the holder 16 will be rotated by 17 around a rotation @Ct perpendicular to the photosensitive object (projection surface) 9. The laser beam rotates in the direction of the arrow 21, and as a result, the 1-reflection boundary 7 also rotates, and is reflected by the reflector 7 and horizontally scanned onto the photoreceptor 9.The angle formed by the trajectory of the laser spot with zllII θ can be adjusted. In order to draw a desired pattern on the photoreceptor 9, a laser beam ray is turned on between the rotating polygon mirror 4 and the laser light source 1.

It is necessary to provide an optical switching element for turning off.

Here, in order to adjust the angle formed by the moving direction y of the stage 10 and the scanning direction X of the laser spot, the angle to be adjusted must be measured.

Below, the method for measuring the angle to be adjusted will be explained in the fifth section.
This will be explained next with reference to FIGS.

In Fig. 5, 30A, 30B, 30C...
(c) The loci of the laser spot horizontally scanned on the photosensitive material, and the angles of these loci with the y-axis must be adjusted to be at right angles as shown.

Now, it is assumed that before adjustment, the locus of the laser spot is as shown by the broken line 1, and the angle it makes with the X axis is θ.

As shown in Fig. 6 (aL (b)), by drawing data, by using numerical data that are orthogonal to each other on the two photoreceptors, a straight line stone!

Draw t1□ and + + A22. Here the straight line hst
Lzl has the same length S and two straight lines t+++
The angle formed by A12 (121+t22) is a right angle on the numerical data to be drawn, but the actually drawn pattern is not a right angle.

Next, one of the drawn patterns (a) and (b) (here, the pattern (b)) is repeated, and the other pattern (here, the pattern (a)) is replaced with the sixth pattern. figure(
c) Straight line tI2 + A22 in the y-axis direction as shown in K
Align so that they overlap. And the straight line L++ in the X-axis direction
If we measure the distance δ between one end 32.36 of vL2+, we get (
2) From the formula, the angle formed by the straight line 41 and A21, that is, X
The inclination angle θ of the scanning trajectory with respect to the axis is determined. In addition.

Here, it is assumed that θ is a small angle.

δ Once this inclination angle θ is determined, in FIG. 6, from the distance t between the rotation axis Ct and the micrometer 17, the feed amount of the micrometer 7 ε&:i: (obtained from Equation 31).

It is assumed that the angle θ is a small angle.

ε = t・θ If the micrometer 7 corrects the feed Mt obtained by passing p in this way, the reflection/female 7 will move to the rotation mechanism 1.
The locus of the laser spot that rotates slightly around 60 and scans horizontally on the photoreceptor (target object) is 3OA in Figure 5.
, 30B, 30C..., the angles formed with the y-axis (all of them are adjusted to be at right angles, that is, in accordance with the orthogonal coordinate system on the object).

Note that if the laser beam incident on the photosensitive material is not perpendicular to the photosensitive surface, the distance on the optical axis from the fθ1/lens 6 to the photosensitive material will change, causing an error in the size of the drawn pattern. However, in the present invention, the center of rotation of the reflecting mirror 7 is provided at the center of the scanning range in the It does not change on the optical axis.

Therefore, no error occurs in the size of the drawn pattern.

FIG. 7V is an explanatory diagram of another method for measuring the angle θ between the scanning locus and the X axis. Here, we are using one photosensitive material, and we happily draw two straight lines 4111 stone 2 that are perpendicular to each other in the drawing data as shown in Figure 7(a). The photosensitive material is then rotated 90° clockwise, and two 1-self lines t2 and 122, which are perpendicular to each other in the drawing data, are drawn as shown in FIG. 7(b). Subsequently, this is developed to obtain a pattern as shown in FIG. 7(C). (2) In this pattern, k u
If the angle γ where the extension of the W line tor 122 intersects and the angle β where the extension of the straight line m A121 A21 intersect, the inclination angle θ of the scanning locus with respect to the two axes can be found from equation (4).

FIG. 8 shows another embodiment of the present invention in which the rotation angle of the reflection boundary 7 is controlled so that the anti-polarity is always maintained accurately no matter how the scanning speed of the laser spot changes. FIG. 2 is a block diagram showing a main part configuration.

(7) In the actual Na example, the device r (
In this case, a drive unit 50 such as a motor is used in place of the micrometer 17 that rotates the halter 16 (reflector 7). In FIG. 8, 51 is an arithmetic processing unit such as a microcomputer, 52 is a motor control circuit that rotates the IJ gong mirror 4 at a predetermined number of rotations, and 56 is a motor drive circuit for the motor 12 that drives the stage 10. be. The arithmetic processing unit 651 outputs a signal "Jz" related to the scanning speed in the X direction by the polygon mirror 4 and the stage 1
A signal vy related to the moving speed of 0 in the y direction is inputted to the motor control circuit 52. The rotational speed of the polygo mirror 4 and the moving speed of the stage 10 are further determined by the motor drive circuit 53, and the horizontal movement angle of the reflecting mirror 7 is determined by the drive unit 50 based on the signal Vxr VyO value. It is controlled as follows. As a result, no matter how the scanning (rusk format) speed of the laser spot changes, it is possible to always perform accurate two-dimensional scanning on the object according to the autorthogonal coordinate system.

In addition, in each of the above embodiments, the case where a rotating polygon mirror is used as the X-direction scanning means is exemplified for both t''L and (
Alternatively, a galvanometer mirror or other scanning means may be used. In addition, in the above embodiment, the reflection source is supported by a holder, and the reflection source is rotated by a rotation mechanism provided on the holder, but these structures are limited to those shown. However, other configuration means may be used. A pentaprism or the like is also used as a reflection source.

As explained above, according to the present invention, it is possible not only to realize an optical scanning device capable of accurate two-dimensional scanning on an object according to an orthogonal coordinate system, but also to realize an optical scanning device that can perform accurate two-dimensional scanning on an object according to an orthogonal coordinate system. It also has the advantage of being able to construct an accurate oblique extension system1.
Ru.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the scanning trajectory of a laser spot of a conventional device, and FIG. 2 is an explanatory diagram showing an example of the device according to the present invention.
FIG. 6 is a plan layout showing the main parts of the device; FIG. 4 is a sectional view of the reflector and poler; f! f, Figures 5 to 7 1ql are explanatory diagrams of a method for measuring the angle formed by the scanning locus of the laser spot with the X axis, and Figure 8 is a block diagram of the upper configuration showing another embodiment of the present invention. 1... Laser light source 4... Rotating polygon mirror 6.
...Fθ lens 7...Reflector 10...Stage 16...Holder 17...Micrometer representative -7F R. Kimura Yo Akira Figure 3 Otsu Figure 5 Ward 3 ■KaVq

Claims (2)

[Claims] (1) A scanning device that linearly scans a light beam in the X direction, and a moving device that moves an object to be drawn by the light beam in an X direction that intersects with the X direction, and forms a desired pattern on the object. In an optical scanning device for drawing, the light beam in the scanning range in the and an adjusting means for rotating the reflecting means, so that the angle between the trajectory of the light spot scanning the object in two directions and two predetermined axes on the object can be adjusted by the adjusting means. An optical scanning device characterized by: (2) The adjustment means adjusts the scanning speed m of the scanning means.
2. The optical scanning device according to claim 1, wherein the rotation angle of the reflecting means is adjusted according to the ratio of the moving speed of the moving means and the moving speed of the moving means.