JPH10157051A - Apparatus and method for positioning beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately position an optical beam in a range of a visual field of an imaging means in a short time. SOLUTION: This apparatus moves an exposure head 1 from a mechanical origin to a position of a CCD camera 2. Then, a laser beam is scanned by the head 1, and a beam image is input as image data by a CCD camera 2. The head 1 is moved based on the image data so that the overall beam image is disposed in a visual field of the camera 2, and zooming magnification is enlarged. A laser beam is lit at predetermined one or a plurality of dots in a scanning range by the head 1, the image is input as image data to the camera 2. The head 1 is moved based on the image data so that the images of the respective dots are positioned at a center of a frame of the camera 2, the position of the dot is measured with a length measuring origin as a reference, and further an interval between the dots is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam positioning device and a positioning method for positioning a light beam in a field of view of an imaging means in a beam irradiation device for irradiating a light beam to an object.

[0002]

2. Description of the Related Art A beam irradiation apparatus is used to irradiate an object with a light beam to draw or process the object. For example, in a drawing apparatus using a light beam, a light beam modulated in accordance with a drawing signal is irradiated on a drawing target such as a photosensitive material while scanning in a main scanning direction, and a drawing target and a scanning optical system are used. Are relatively moved in the sub-scanning direction, thereby drawing on the drawing target at a constant sub-scanning pitch.

In such a drawing apparatus, since the shape of the light beam may change, a preparatory step before drawing is performed.
The shape of the light beam is observed with a two-dimensional CCD (charge coupled device) camera. In this case, the exposure head that emits the light beam is roughly moved to the position of the CCD camera, the focus is roughly adjusted, and the photosensitive material is removed while the operator looks at the image captured by the CCD camera on the monitor. The mounted table and exposure head are finely moved by manual operation to search for a beam image, finely adjust the focus, and finely adjust the position of the beam image.

[0004]

In the above-mentioned conventional method, since it is necessary for the operator to manually position the beam and observe the beam image, the positioning of the light beam in the preparation stage before the actual drawing is performed. Observation requires a lot of time. In order to reduce the time required for positioning the light beam in such a preparation stage, the positions of the exposure head and the table adjusted in the previous positioning are stored and used as reference in the next positioning. ing.

However, the mechanical origin of the exposure head and the table slightly fluctuates for each positioning. In light beam observation, a very small diameter beam image is magnified and observed with a CCD camera. Therefore, only a small change in the mechanical origin of the exposure head and table causes a part of the beam image to be viewed by the CCD camera. Often deviates from. Therefore, the positions of the exposure head and the table stored at the time of the previous positioning are often not useful after all.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a beam positioning apparatus and a beam positioning method capable of accurately positioning a light beam within a field of view of an imaging means in a short time.

[0007]

Means for Solving the Problems and Effects of the Invention

(1) First invention A beam positioning device according to a first invention is a beam positioning device that positions a light beam within a visual field of an imaging unit in a beam irradiation device that irradiates a light beam to an object. A light beam emitting unit, an imaging unit, a driving unit, and a control unit are provided.

The light beam emitting means emits a light beam.
The imaging means captures a beam image from the light beam emitting means as image data. The driving unit moves the light beam emitting unit relatively to the imaging unit.

The control means moves the light beam emitting means to the position of the imaging means by the driving means, emits the light beam by the light beam emitting means, captures the beam image as image data by the imaging means, and captures the beam image by the imaging means. The beam image is positioned at a predetermined position within the field of view of the imaging means by adjusting the relative position between the light beam emitting means and the imaging means by the driving means based on the image data obtained.

In the beam positioning apparatus according to the present invention, after the light beam emitting means has moved to the position of the imaging means, a beam image by the light beam emitting means is captured as image data by the imaging means, and based on the image data. By adjusting the relative position between the light beam emitting means and the imaging means, the beam image is positioned at a predetermined position in the field of view of the imaging means.

Thus, even if the mechanical origin of the drive system changes, the beam image can be accurately and automatically positioned at a predetermined position in the field of view of the imaging means in a short time. (2) Second invention A beam positioning device according to a second invention is the configuration of the beam positioning device according to the first invention, wherein the light beam emitting means causes the light beam to be emitted at a predetermined dot pitch in the main scanning direction. The driving means moves the light beam emitting means and the imaging means relatively in the main scanning direction and the sub-scanning direction, and the control means moves the light beam emitting means from the mechanical origin by the driving means to the imaging means. After being moved to the position, the light beam is scanned by the light beam emitting unit, the beam image is captured as image data by the imaging unit, and the light beam emitting unit and the imaging unit are driven by the driving unit based on the image data captured by the imaging unit. By adjusting the relative position with respect to the beam image, the beam image is positioned within the field of view of the imaging means, and the imaging means is set at a predetermined imaging magnification. The light beam is turned on by one or a plurality of predetermined dots within the scanning range, the beam image is captured as image data by the imaging unit, and the driving unit performs imaging with the light beam emitting unit based on the image data captured by the imaging unit. By adjusting the relative position with respect to the means, the beam image of one or more predetermined dots is sequentially positioned at a predetermined position in the field of view of the imaging means.

In this case, the relative position between the light beam emitting means and the imaging means is adjusted so that the beam image obtained by scanning of the light beam emitting means is located within the field of view of the imaging means, and the imaging means is adjusted to a predetermined imaging magnification. After the setting, the light beam is turned on at one or a plurality of predetermined dots within the scanning range by the light beam emitting unit, and the beam image is captured as image data by the imaging unit. The relative position between the light beam emitting unit and the imaging unit is adjusted so that the beam image of one or more predetermined dots is sequentially positioned at a predetermined position in the field of view of the imaging unit based on the captured image data.

Accordingly, it is possible to automatically and accurately position the beam image at one or a plurality of dots in the scanning range at a predetermined position in the field of view of the imaging means in a short time.

(3) Third invention A beam positioning device according to a third invention is the beam positioning device according to the first or second invention, wherein the image data captured by the imaging means is converted into an image. It further comprises display means for displaying. Thereby, the light beam imaged by the imaging means can be observed.

(4) Fourth invention A beam positioning device according to a fourth invention is the beam positioning device according to the second or third invention, wherein the light beam emitting means is located at the mechanical origin. A measuring means for initializing the measurement origin and measuring a moving distance of the light beam emitting means from the measuring origin, and a moving distance measured by the measuring means after the relative position between the light beam emitting means and the imaging means is adjusted And dot position calculating means for calculating the position of one or a plurality of dots based on the measurement origin based on the image data taken in by the image pickup means.

In this case, the measurement origin is initialized when the light beam emitting means is located at the mechanical origin, and the moving distance of the light beam emitting means from the measurement origin is measured. The position of one or more dots with respect to the measurement origin is calculated based on the moving distance of the light beam emitting unit from the measurement origin and the image data captured by the imaging unit.

As described above, since the measurement origin is reset before the measurement of the moving distance, even if the mechanical origin fluctuates, the position of one or a plurality of dots with respect to the measurement origin is accurately calculated. .

(5) Fifth invention A beam positioning device according to a fifth invention is the beam positioning device according to the fourth invention, wherein the control means includes a light beam emitting means for controlling a predetermined position within a scanning range. The light beam is turned on with the plurality of dots, and the beam images of the plurality of dots are captured as image data by the imaging unit, and the dot position calculation unit calculates the positions of the plurality of dots with reference to the measurement origin, and calculates the dot position. The apparatus further includes a dot interval calculation unit that calculates a dot interval based on the positions of the plurality of dots calculated by the unit.

In this case, since the positions of the plurality of dots with respect to the measurement origin are accurately calculated, the dot interval is also accurately calculated based on the positions of the plurality of dots. (6) Sixth invention A beam positioning method according to a sixth invention is a beam positioning method for positioning a light beam within a field of view of an imaging unit in a beam irradiation device that irradiates a light beam to an object. The method includes a first step, a second step, and a third step.

In the first step, the light beam emitting means is moved to the position of the imaging means. In the second step, a light beam is emitted by the light beam emitting means, and a beam image is captured as image data by the imaging means. In the third step, the beam image is positioned at a predetermined position in the field of view of the imaging unit by adjusting the relative position between the light beam emitting unit and the imaging unit based on the image data captured by the imaging unit.

In the beam positioning method according to the present invention, after the light beam emitting means moves to the position of the imaging means, a beam image by the light beam emitting means is captured as image data by the imaging means, and based on the image data. By adjusting the relative position between the light beam emitting means and the imaging means, the beam image is positioned at a predetermined position in the field of view of the imaging means.

Thus, even if the mechanical origin of the drive system changes, the beam image can be accurately and automatically positioned at a predetermined position in the field of view of the imaging means in a short time. (7) Seventh invention A beam positioning method according to a seventh invention is directed to a beam positioning method according to the sixth invention, wherein the first step comprises:
The second step includes moving the light beam emitting means from the mechanical origin to the position of the imaging means, and the light beam emitting means scans the light beam at a predetermined dot pitch in the main scanning direction to capture a beam image. Means for capturing a beam image as image data by the means, wherein the third step adjusts a relative position between the light beam emitting means and the image capturing means based on the image data captured by the image capturing means, thereby obtaining a field of view of the image capturing means. Setting the imaging means to a predetermined imaging magnification and illuminating the light beam with one or a plurality of predetermined dots within the scanning range by the light beam emitting means and turning the beam image into image data by the imaging means The capturing step and adjusting the relative position between the light beam emitting unit and the imaging unit based on the image data captured by the imaging unit. It is intended to include the step of sequentially positioning the beam image of one or more dots of constant at a predetermined position within the field of view of the imaging means.

In this case, the relative position between the light beam emitting means and the imaging means is adjusted so that the beam image obtained by scanning of the light beam emitting means is located within the field of view of the imaging means, and the imaging means is adjusted to a predetermined imaging magnification. After the setting, the light beam is turned on at one or a plurality of predetermined dots within the scanning range by the light beam emitting unit, and the beam image is captured as image data by the imaging unit. The relative position between the light beam emitting unit and the imaging unit is adjusted so that the beam image of one or more predetermined dots is sequentially positioned at a predetermined position in the field of view of the imaging unit based on the captured image data.

Therefore, it is possible to automatically and accurately position the beam image at one or a plurality of dots in the scanning range at a predetermined position in the field of view of the imaging means.

[0025]

FIG. 1 is a block diagram of a drawing apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic perspective view of the drawing apparatus of FIG. The drawing apparatus of the present embodiment is an exposure apparatus of a division exposure system.

The drawing apparatus shown in FIG. 1 includes an exposure head 1, a CCD
(Charge Coupled Device) A camera 2, a table 3, an X-axis drive motor 4, and a Y-axis drive motor 5 are provided. Exposure head 1
Irradiates the laser beam on the table 3 while scanning the laser beam in the X-axis direction (main scanning direction) with a predetermined scanning width. The CCD camera 2 is buried in a predetermined position of the table 3,
Move with. The CCD camera 2 captures a beam image of the laser beam irradiated on the table 3 by the exposure head 1 as image data.

As shown in FIG. 2, the table 3 includes a base 1
The guide 5 is movably guided in the Y-axis direction (sub-scanning direction) by a table guide 16 arranged on the upper surface 5. The table 3 is driven in the Y-axis direction by a Y-axis drive motor 5 (see FIG. 1). At the time of drawing, the photosensitive material 10 is placed on the table 3.
0 is placed.

The exposure head 1 is guided by a head guide 17 above the table 3 so as to be movable in the X-axis direction (main scanning direction). The exposure head 1 is connected to the X-axis drive motor 4 via a ball screw 18,
It is driven in the X-axis direction by an X-axis drive motor 4.

The drawing apparatus shown in FIG. 1 has a laser controller 6, a CC
D camera interface 7, X-axis drive motor controller 8,
It further includes a Y-axis drive motor controller 9, a CCD camera monitor 10, a memory 11, a CPU (Central Processing Unit) 12, and a laser length measuring device 13.

The laser controller 6 controls on / off (turn on / off) of a laser beam by the exposure head 1 and scanning in the X-axis direction. CCD camera interface 5
The image data captured by the CD camera 2 is given to the CCD camera monitor 10 and the memory 11.

The X-axis drive motor controller 8 controls the X-axis drive motor 4, and the Y-axis drive motor controller 9 controls the Y-axis drive motor 5. The CCD camera monitor 10 displays the image data captured by the CCD camera 2 as an image. The memory 11 stores image data captured by the CCD camera 2. The CPU 12 controls the entire drawing apparatus.

The laser length measuring device 13 measures the moving distance of the exposure head 1 and the table 3 from the origin of the length measuring device. Thus, the position of the CCD camera 1 with respect to the length measuring instrument origin is calculated.

In this embodiment, the exposure head 1 corresponds to the light beam emitting means, the CCD camera 2 corresponds to the image pickup means,
The X-axis drive motor 4 and the Y-axis drive motor 5 correspond to a drive unit. Further, the laser controller 6, the X-axis drive motor controller 8, the Y-axis drive motor controller 9, and the CPU 12 correspond to the control means. Further, the CCD camera monitor 10 corresponds to a display unit, and the laser length measuring device 13 corresponds to a measurement unit. Further, the memory 11 and the CPU 12 constitute a dot position calculating means and a dot interval calculating means.

In the drawing apparatus of FIG. 1, as shown in FIG.
The laser beam B is deflected and scanned at a predetermined dot pitch in the X-axis direction (main scanning direction) while moving the photosensitive material 100 from the origin side at a substantially constant speed in the Y-axis direction (sub-scanning direction). An image is drawn on the surface of the photosensitive material 100 with a constant scanning width W.

When the photosensitive material 100 moves to the end of the stroke, the photosensitive material 100 is returned to the origin in the Y-axis direction, and the exposure head 1 is moved in the X-axis direction by a fixed distance. Thereafter, the photosensitive material 100 is moved in the Y-axis direction and the laser beam B is scanned in the X-axis direction.

By repeating such an operation, a strip-shaped area (stripe area) 101 on the photosensitive material 100 is obtained.
Exposure is performed sequentially every time, and finally, drawing is performed on the entire surface of the photosensitive material 100.

In the writing of each stripe area 101, a laser beam is turned on or off for each dot on a scanning line and is scanned in the X-axis direction based on a writing signal, and a beam image is formed on the photosensitive member 100.

Next, the beam positioning operation in the drawing apparatus of FIG. 1 will be described with reference to FIGS. The beam positioning operation includes a preposition operation and a dot positioning operation.

FIG. 4 is a flowchart showing the pre-position operation, and FIGS. 5 and 6 are flowcharts showing the focus adjustment processing. FIG. 7 is a flowchart showing a dot positioning operation, and FIG. 8 is a flowchart showing a dot position measuring process.

First, the preposition operation will be described with reference to FIG. 4, FIG. 9 and FIG. First, the table 3 and the exposure head 1 are returned to the mechanical origin, and the origin of the table 3 and the exposure head 1 is initialized by setting the measurement origin of the laser length measuring device 13 to the mechanical origin (FIG. Step S1).

Next, based on the distance from the mechanical origin determined in the design to the CCD camera 2, the exposure head 1
Move to the position of the CD camera 2 (step S2), and
The field of view is enlarged by reducing the zoom magnification of the D camera 2 (step S3). Then, the CCD camera 2 is moved in the Z-axis direction (vertical axis direction) for rough focus adjustment (step S4).

Next, the exposure head 1 scans the stripe area while illuminating the laser beam with all dots (all points) (step S5). FIG. 9A shows the scanning of the laser beam B in this case. At this time, the image displayed on the CCD camera monitor 10 is as shown in FIG.

Next, the beam image is captured as image data by the CCD camera 2, and based on the image data, the C
The position of the beam image on the frame of the CD camera 2 is detected (step S6). Then, the exposure head 1 and the table 3 are moved so that the beam image is located at the center of the frame of the CCD camera 2 (step S7). At this time, the image displayed on the CCD camera monitor 10 is as shown in FIG.
(B). In this state, after performing fine adjustment of the focus shown in FIGS. 6 and 7 (step S8), C
The zoom magnification of the CD camera 2 is adjusted to a value suitable for observing the beam image (Step S9). At this time, the image displayed on the CCD camera monitor 10 is as shown in FIG.

Here, the focus adjustment processing will be described with reference to the flowcharts of FIGS. First,
The CCD camera 2 is moved to the upper end in the Z-axis direction (Step S21 in FIG. 5). Next, the beam image is captured as image data by the CCD camera 2 (step S22). The peak value of the brightness of the beam image is measured based on the captured image data (step S23), and the peak value is compared with a specified value (step S24). If the luminance peak value does not match the specified value, the CCD camera is moved downward (step S25), and the processing of steps S22 to S24 is repeated.

When the luminance peak value matches the specified value, the width of the beam image is measured based on the captured image data (step S26 in FIG. 6). Then, the CCD camera 2 is moved in the Z-axis direction so as to reduce the width of the beam image (step S27), and the beam image is captured by the CCD camera 2 as image data (step S28). The width of the beam image is measured based on the captured image data (step S29), and it is determined whether the width of the beam image is minimum (step S30). If the width of the beam image is not the minimum, the processing of steps S27 to S30 is repeated, and the focus adjustment ends when the width of the beam image becomes the minimum.

Next, the dot positioning operation will be described with reference to FIGS. First, the exposure head 1 scans the stripe region while lighting the laser beam with one or a plurality of predetermined dots (step S1).
1). Here, as shown in FIG. 9B, the laser beam B is lit by dots at both ends and dots at the center. At this time, an image displayed on the CCD camera monitor 10 is as shown in FIG.

Next, the exposure head 1 is moved so that the beam image of one dot is located substantially at the center of the frame of the CCD camera 2 (step S12). Here, for example, the beam image of the dot at the right end is located at the center of the CCD camera 2. At this time, the image displayed on the CCD camera monitor 10 is as shown in FIG. In this state, the dot position is measured with reference to the length measurement origin by performing the dot position measurement processing shown in FIG. 8 (step S1).
3).

Thereafter, the dot shape (shape of the beam image) is observed on the CCD camera monitor 10 (step S1).
4). If the measurement of the dot position and the observation of the dot shape have not been completed for all the predetermined dots (step S15), the exposure head is set so that the beam image of the next dot is located substantially at the center of the frame of the CCD camera 2. 1
Is moved (step S16). And step S
Steps 13 to 15 are repeated. When the measurement of the dot position and the observation of the dot shape are completed for all the predetermined dots, the interval between the dots is calculated based on the measured plurality of dot positions (step S17).

Here, the flowchart of FIG.
The dot position measurement process will be described with reference to FIG. First, the position of the origin P1 of the frame 20 of the CCD camera 2 with respect to the measurement origin P0 is measured by measuring the distance from the measurement origin P0 to the exposure head 1 and the table 3 using the laser length measuring device 3. Measure (Step S
31).

Further, based on the image data captured by the CCD camera 2, the resolution and the zoom magnification of the CCD camera 2, the center of gravity P2 of the dot 103 is calculated with reference to the position of the origin P0 of the frame 20 of the CCD camera 2. (Step S32). Further, the position of the origin P1 of the frame 20 with respect to the measurement origin P0 and the frame 20
The center of gravity P2 of the dot 103 based on the measurement origin P0 is calculated based on the center of gravity P2 of the dot 103 based on the origin P1 (step S33).

In this case, the exposure head 1 and the table 3 are returned to the mechanical origin at the beginning of the pre-position operation, and the length measuring origin P0 is reset in that state. Even if it changes every time, the barycentric position P2 of the dot 103 with reference to the length measurement origin P0 can be obtained accurately.

As described above, according to the drawing apparatus of the present embodiment, the beam image of a predetermined dot within the scanning range can be accurately and quickly set within the field of view of the CCD camera 2 in the preparation stage before drawing. Positioned automatically. The positioned beam image is displayed on the CCD camera monitor 10. Further, the positions of the dots with respect to the measurement origin are accurately measured, and the intervals between the dots are accurately calculated. Therefore, the shape of the dots and the interval between the dots can be easily and quickly inspected.

In the above embodiment, the CCD camera 2 is arranged on the lower surface of the table 3, but the CCD camera 2 may be arranged above the table 3.

[Brief description of the drawings]

FIG. 1 is a block diagram of a drawing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of the drawing apparatus of FIG. 1;

FIG. 3 is a perspective view showing drawing by the drawing apparatus of FIG. 1;

FIG. 4 is a flowchart showing a preposition operation in the drawing apparatus of FIG. 1;

FIG. 5 is a flowchart illustrating focus adjustment processing.

FIG. 6 is a flowchart illustrating a focus adjustment process.

FIG. 7 is a flowchart showing a dot positioning operation in the drawing apparatus of FIG. 1;

FIG. 8 is a flowchart illustrating a dot position measurement process.

FIG. 9 is a diagram showing scanning of a laser beam.

FIG. 10 is a diagram showing an image displayed by a CCD camera monitor in a preposition operation and a dot positioning operation.

FIG. 11 is a diagram illustrating the principle of dot position measurement processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exposure head 2 CCD camera 3 Table 4 X-axis drive motor 5 Y-axis drive motor 6 Laser controller 8 X-axis drive motor controller 9 Y-axis drive motor controller 10 CCD camera monitor 11 Memory 12 CPU 13 Laser length measuring device 100 Photosensitive material

Claims (7)

[Claims] 1. A beam positioning device for positioning a light beam within a field of view of an imaging means in a beam irradiation device for irradiating a light beam onto an object, comprising: a light beam emitting means for emitting a light beam; Imaging means for capturing a beam image by the emission means as image data; driving means for moving the light beam emission means relative to the imaging means; and a position of the imaging means for driving the light beam emission means by the driving means. The light beam is emitted by the light beam emitting means, the beam image is captured as image data by the image capturing means, and the light beam emitting means is driven by the driving means based on the image data captured by the image capturing means. The beam image is adjusted to a predetermined position in the field of view of the imaging unit by adjusting a relative position with respect to the imaging unit. Positioning device of the beam, characterized in that a control means for fit-decided. 2. The light beam emitting means causes the light beam to scan in a main scanning direction at a predetermined dot pitch, and the driving means relatively moves the light beam emitting means and the imaging means in the main scanning direction and After moving the light beam emitting means from the mechanical origin to the position of the imaging means by the driving means, the control means moves the light beam emitting means to the position of the imaging means, and then scans the light beam by the light beam emitting means. The image is captured by the imaging unit as image data, and the beam image is captured by adjusting the relative position between the light beam emitting unit and the imaging unit by the driving unit based on the image data captured by the imaging unit. It is positioned within the field of view of the imaging means, the imaging means is set at a predetermined imaging magnification, and the light beam emitting means is used to set a predetermined one within a scanning range. The light beam is turned on by a plurality of dots, a beam image is captured as image data by the imaging unit, and the light beam emission unit and the imaging unit are connected by the driving unit based on the image data captured by the imaging unit. 2. The beam positioning device according to claim 1, wherein a beam image of the predetermined one or a plurality of dots is sequentially positioned at a predetermined position within a field of view of the imaging unit by adjusting a relative position. 3. The beam positioning device according to claim 1, further comprising a display unit that displays the image data captured by the imaging unit as an image. 4. A measuring means for initializing a measurement origin when the light beam emitting means is located at a mechanical origin, and measuring a moving distance of the light beam emitting means from the measuring origin, and the light beam emitting means. After the relative position of the one or a plurality of dots is adjusted with respect to the measurement origin based on the moving distance measured by the measuring means and the image data captured by the imaging means after the relative position between the measuring means and the imaging means is adjusted. 4. The beam positioning device according to claim 2, further comprising a dot position calculating means for calculating a position. 5. The control unit according to claim 1, wherein the light beam emission unit turns on a light beam at a plurality of predetermined dots within a scanning range, captures a beam image of the plurality of dots as image data by the imaging unit, Dot position calculating means calculates the positions of the plurality of dots with reference to the measurement origin, and calculates a dot interval based on the positions of the plurality of dots calculated by the dot position calculating means. The beam positioning device according to claim 4, further comprising: 6. A beam positioning method for positioning a light beam within a field of view of an imaging means in a beam irradiation device for irradiating a light beam to an object, wherein the light beam emission means is moved to a position of the imaging means. A first step of emitting a light beam by the light beam emitting means and capturing a beam image as image data by the imaging means;
Positioning the beam image at a predetermined position within the field of view of the imaging means by adjusting the relative position of the light beam emitting means and the imaging means based on the image data captured by the imaging means. And a third step of performing beam positioning. 7. The first step includes a step of moving the light beam emitting unit from a mechanical origin to a position of the image pickup unit, and the second step includes changing a light beam by the light beam emitting unit. Scanning the main beam in a main scanning direction at a predetermined dot pitch to capture a beam image as image data by the imaging unit; and the third step includes emitting the light beam based on the image data captured by the imaging unit. Positioning the beam image within the field of view of the imaging means by adjusting a relative position between the means and the imaging means, and setting the imaging means to a predetermined imaging magnification; and a scanning range by the light beam emitting means. Turning on a light beam with one or a plurality of predetermined dots in the image, and capturing a beam image as image data by the imaging means; By adjusting a relative position between the light beam emitting unit and the imaging unit based on the captured image data, the beam image of the predetermined one or a plurality of dots is sequentially placed at a predetermined position in the visual field of the imaging unit. 7. The method according to claim 6, further comprising the step of positioning.