JPH11237307A - Measuring method and adjusting method for focus position of laser beam emitted by laser beam emission optical unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make measurable the focus position of a laser beam with high precision in a short time. SOLUTION: The laser beam emission optical system 1 emits the laser beam. Then, while a lens barrel 2 containing a collimator lens is moved repeatedly between a specific movement initial position and a movement end position along the optical axis, light quantity values of LB at measurement points set at constant movement intervals are repeatedly inputted by a TV camera 4. Then, the mean value of the inputted light quantity values of the LB is calculated to calculate a light quantity value distribution and the position of the collimator lens where the light quantity value of the LB becomes maximum is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for scanning a photosensitive drum with a laser beam modulated by an image signal, thereby transferring an image visualized on the photosensitive drum to a recording medium such as a recording paper. The present invention relates to a focus position measuring method and a focus position adjusting method of a laser beam emitted from a laser emitting optical unit used for a laser beam printer or the like that performs recording by using a laser beam.

[0002]

2. Description of the Related Art In recent years, as a recording apparatus for recording an image on a recording medium, a laser beam is scanned on a photosensitive drum,
2. Description of the Related Art A laser beam printer that transfers an image visualized on a photosensitive drum to a recording medium to perform recording is widely used.

FIG. 4 is a perspective view showing a schematic configuration of a laser scanning optical system in a conventional laser beam printer.

As shown in FIG. 4, a laser scanning optical system in a conventional laser beam printer includes a semiconductor laser light source 101 that radially emits a laser beam, and a parallel light beam (ie, a laser beam emitted from the semiconductor laser light source 101). , A laser beam emitting optical unit having a collimator lens 102, an imaging optical system 103 for linearly condensing the laser beam transmitted through the collimator lens 102, and a laser beam condensing by the imaging optical system 103. A polygon mirror 104 provided with a deflecting / reflecting surface 104a on the side surface for reflecting the laser light, and rotated about an axis O by a motor 105;
The fθ lens 106 focuses the laser beam deflected and scanned at 04 on the surface of the photosensitive drum 107.

A laser beam modulated by an image signal and emitted from a semiconductor laser light source 101 is collimated by a collimator lens 72, deflected by a rotating polygon mirror 104, and further deflected by an fθ lens 1.
At 06, an image is formed on the photosensitive drum 107, and the photosensitive drum 107 is scanned in the B direction in the figure. The photosensitive drum 107 is driven by a driving unit (not shown) around an X axis shown as a central axis of the photosensitive drum 107 itself.
Rotated in the direction.

As described above, the main scanning of the laser beam is performed in the direction B by the rotation of the polygon mirror 104 on the surface of the photosensitive drum 107, and the sub-scanning is performed by rotating the photosensitive drum 107 around the X axis. Is performed. Thus, an electrostatic latent image is formed on the surface of the photosensitive drum 107.

A corona discharger for uniformly charging the surface of the photosensitive drum 107 is provided around the photosensitive drum 107, and a developing device for developing an electrostatic latent image formed on the surface of the photosensitive drum 107 into a toner image. An image forming device, a corona discharger for transfer (not shown) for transferring the toner image onto a recording paper, and the like are arranged. By these operations, recording corresponding to the laser light emitted from the semiconductor laser light source 101 is performed. Information
It is recorded on a recording medium such as recording paper (not shown). The above is well known as an electrophotographic recording technique.

Next, a laser beam emitting optical unit having the semiconductor laser light source and the collimator lens shown in FIG. 4 will be described with reference to FIG. FIG.
FIG. 5 is a sectional view showing a laser beam emitting optical unit in the laser scanning optical system shown in FIG.

In the laser beam emitting optical unit 111, the semiconductor laser light source 101 is connected to the light emission control circuit board 10.
8 and their semiconductor laser light sources 101
The light emission control circuit board 108 is fixed to the holder 109. Further, a lens barrel 110 holding the colimeter lens 102 inside is fixed to the holder 109. The lens barrel 110 adjusts the irradiation position of the laser beam by moving the lens barrel 110 in a direction perpendicular to the optical axis of the semiconductor laser light source 101, and further moves the lens barrel 110 in the optical axis direction of the laser beam emission optical unit 111. Is moved to adjust the focus of the laser beam.
9 and assembled.

Next, a laser beam irradiation position adjusting step and a focus adjusting step in the laser beam emitting optical unit shown in FIG. 5 will be described with reference to FIG. 6 and the like. FIG. 6 is a schematic configuration diagram showing an adjustment device for adjusting a laser beam irradiation position, a focus adjustment, and an inspection in the laser beam emission optical unit shown in FIG.

First, the step of adjusting the irradiation position of the laser beam in the laser beam emitting optical unit 111 will be described. In the laser beam irradiation position adjustment step, first, the laser driver 112 is driven to emit a laser beam from the laser beam emission optical unit 111, and this laser beam is used as a light detection sensor as a T sensor.
The light is received by the V camera 113. Then, the output signal becomes T
The image data is transmitted from the V camera 113 to the image processing device 114, and the image processing device 114 calculates the beam center of gravity of the laser beam. The host computer 115 transmits the lens barrel moving unit 11 via the controller 116 based on the calculated value.
7, the lens barrel 110 is moved until the beam center of gravity of the laser beam is moved to a predetermined position. Thereby, the irradiation position of the laser beam is adjusted.

Next, the step of adjusting the focus of the laser beam will be described. In the laser beam focus adjustment step, first, the laser driver 112 is driven to emit a laser beam from the laser beam emission optical unit 111. Subsequently, the lens barrel moving unit 117 is operated to move the lens barrel 110 to the laser beam emitting optical unit 1.
11 while moving in the optical axis direction,
The light is received by the camera 113.

When the output signal is transmitted from the TV camera 113 to the image processing device 114, the relationship between the movement position of the lens barrel 110 and the light amount of the laser beam as shown in FIG. 7 is obtained. The host computer 115 calculates the positions a and b of the lens barrel 110 at which the light amount of the laser beam becomes 90% of the maximum light amount, and further calculates an intermediate position between the positions a and b. Since this intermediate position is regarded as the best focus position where the light amount of the laser beam is the maximum, the lens barrel moving unit 117 is controlled via the controller 116,
The lens barrel 110 is positioned so that the lens barrel 110 is located at the intermediate position.
To move. Finally, the lens barrel 110 is adhesively fixed to the holder 109 at the position adjusted as described above. Thereby, the focus position of the laser beam is adjusted.

The inspection of whether or not the focus position of the laser beam emitting optical unit 111 adjusted as described above is within a predetermined standard is performed by the TV camera moving stage 118 using the laser beam emitting optical unit 111. Is performed by moving the TV camera 113 in the direction of the optical axis and calculating the focus position of the laser beam in the same manner as in the above-described focus adjustment step. As a result, a good product and a bad product of the laser beam emitting optical unit 111 are sorted out.

As described above, the conventional laser beam emitting optical unit 111 performs the focus position adjustment after the laser beam irradiation position adjustment is performed,
Finally, a focus position inspection is performed. At this time, in the focus position adjustment step, the laser beam emission optical unit 111
In order to reduce the adjustment man-hour of the lens as much as possible, the movement of the lens barrel 110 is set to a predetermined amount only once. Further, at the time of starting the focus position adjustment or the focus position inspection, after turning on the power to the semiconductor laser light source 101, the focus position adjustment or the focus position inspection is performed at a stage when the laser beam has a specific output. Have been done.

[0016]

However, since the output of the laser beam from the semiconductor laser light source is not stable for a while immediately after the power is turned on, the focus position adjustment of the laser beam emitting optical unit and the laser beam capturing during the inspection are performed. The output of the laser beam fluctuates. Therefore, the relationship between the movement position of the lens barrel and the light amount of the laser beam may be different between immediately after the power is turned on and when the output of the laser beam is stable, as shown in FIG. In this case, the calculated focus position deviates from the actual focus position, and the laser beam emission optical unit adjusted before the output of the laser beam is stabilized becomes a defective product.

In order to eliminate the deviation of the focus position due to the fluctuation of the output of the laser beam, it is necessary to start the adjustment of the focus position and the inspection after a certain time has elapsed after the power supply to the semiconductor laser light source is turned on. However, the waiting time until the light quantity output is stabilized takes ten times or more as compared with the time for the focus position adjustment and the inspection, so that the man-hour for adjusting the laser beam emitting optical unit is greatly increased.

Accordingly, the present invention provides a laser beam emitted from a laser beam emitting optical unit, which can measure the focus position and adjust the focus position of the laser beam in a short time and with high accuracy without being affected by the output fluctuation of the laser beam. It is an object of the present invention to provide a beam focus position measuring method and a focus position adjusting method.

[0019]

In order to achieve the above object, the present invention provides a method for measuring the focus position of a laser beam emitted from a laser beam emitting optical unit, comprising: a laser light source section for irradiating a laser beam; And a collimator lens that forms a laser beam by converting the laser beam emitted from the part into a parallel beam, and a focus position measuring method of a laser beam emitted from a laser beam emission optical unit having the laser beam emission optical unit. Injecting a laser beam, and repeatedly moving the collimator lens in the optical axis direction of the laser beam between a predetermined initial movement position and a final movement position, while measuring the measurement points set at regular intervals. Repeatedly capturing the light intensity value of the laser beam at Averaging the intensity of the captured laser beam, calculating a distribution of the intensity of the averaged laser beam, and further calculating the distribution of the laser beam having the maximum intensity of the laser beam based on the distribution. Calculating the position of the meter lens.

Thus, even before the output of the laser beam emitted from the laser beam emitting optical unit is stabilized, the same focus position as when the output of the laser beam is stabilized is measured. The focus position of the laser beam is measured in a short time with high accuracy without being affected by the fluctuation.

Further, after the step of emitting a laser beam from the laser beam emitting optical unit,
Capturing the light intensity value of the laser beam at a measurement point set at the constant movement interval while moving the collimator lens from the predetermined movement initial position to the movement end position in the optical axis direction of the laser beam. Calculating the irradiation position of the laser beam based on the distribution of the light amount value of the captured laser beam; and performing predetermined irradiation of the irradiation position of the laser beam based on the calculated irradiation position of the laser beam. Calculating the amount and direction of movement of the collimator lens necessary to correct the position, and moving the collimator lens according to the calculated amount and direction of movement, the laser In addition to beam focus position measurement, laser beam irradiation position measurement and Since the fine irradiation position adjustment is performed in a series of adjustment steps, the adjustment steps of the laser beam emitting optical unit is reduced.

Further, according to the method for measuring the focus position of a laser beam emitted from a laser beam emitting optical unit according to the present invention, a laser light source for irradiating a laser beam and the laser beam emitted from the laser light source are made into parallel light. A method for measuring the focus position of a laser beam emitted from a laser beam emitting optical unit having a collimator lens for forming a laser beam, wherein the laser beam is emitted from the laser beam emitting optical unit; While repeatedly moving the light amount detecting means for detecting the amount of light in the optical axis direction of the laser beam between a predetermined movement initial position and a movement end position, the laser beam at a measurement point set at a constant movement interval. Repeatedly capturing the light intensity values of the The collimator lens that averages the light intensity of the laser beam that has entered, calculates the distribution of the light intensity of the averaged laser beam, and further maximizes the light intensity of the laser beam based on the distribution And calculating the position of.

Further, after the step of emitting a laser beam from the laser beam emitting optical unit,
While moving the light amount detecting means for detecting the light amount of the laser beam from the predetermined movement initial position to the movement end position in the optical axis direction of the laser beam, the laser at a measurement point set at the constant movement interval is used. Capturing the light intensity value of the beam, calculating the irradiation position of the laser beam based on the distribution of the light intensity value of the captured laser beam, and calculating the irradiation position of the laser beam based on the calculated irradiation position of the laser beam. Calculating the moving amount and moving direction of the collimator lens necessary to correct the irradiation position to a predetermined irradiation position, and moving the collimator lens according to the calculated moving amount and moving direction. It is preferable to have a configuration.

Further, according to the method for adjusting the focus position of a laser beam emitted from a laser beam emitting optical unit according to the present invention, a laser light source for irradiating a laser beam and the laser beam emitted from the laser light source are converted into parallel light. A focus position of a laser beam emitted from a laser beam emission optical unit having a collimator lens for forming a laser beam, the focus position of a laser beam emitted from the laser beam emission optical unit of the present invention. Measuring a focus position of a laser beam emitted from the laser beam emission optical unit by a measurement method, and moving the collimator lens to the measured focus position of the laser beam. I do.

Thus, even before the output of the laser beam emitted from the laser beam emitting optical unit is stabilized, the same focus position as when the output of the laser beam is stabilized is measured, and the collimator is placed at the focus position. The lens is moved. As a result, the focus position of the laser beam is adjusted in a short time and with high precision, and the measured focus position is prevented from being deviated from the focus position when the output of the laser beam is stabilized. Production efficiency is improved.

[0026]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic structural view showing an adjusting device for adjusting the irradiation position of the laser beam, adjusting the focus, and inspecting the laser beam emitting optical unit.

However, in the adjusting device 10 for the laser beam emitting optical unit shown in FIG. 1, a laser driver 3, a TV camera 4 as a light detection sensor, an image processing device 5, a host computer 6, a controller 7, a lens barrel moving unit 8 , And each configuration and operation of the TV camera moving stage 9 are the same as those of the adjustment device 119 of the laser beam emission optical unit described with reference to FIG.
Detailed description is omitted. The configuration of the laser beam emitting optical unit 1 shown in FIG. 1 and the lens barrel 2 accommodating the collimator lens (not shown) are the same as those of the laser beam emitting optical unit 111 shown in FIG. Is omitted.

FIG. 2 is a flowchart showing the adjustment process of the laser beam emitting optical unit of the present embodiment.
Hereinafter, the adjustment process of the laser beam emitting optical unit of the present embodiment will be described mainly with reference to FIGS.

In the adjustment step of the laser beam emitting optical unit of the present embodiment, first, the lens barrel 2 is moved to a predetermined initial movement position (S1). Next, a laser beam is emitted from the laser beam emitting optical unit 1, and the laser driver 3 is driven so that the light amount of the laser beam reaches a constant output value (S2). When the light amount of the laser beam reaches a certain output value, the lens barrel moving unit 8
The lens barrel 2 is moved along the optical axis of the laser beam (S
3). At this time, the moving speed of the lens barrel 2 is set to twice the conventional speed.

During the movement of the lens barrel 2, it is monitored whether or not the lens barrel 2 has passed a predetermined measurement point (S4). 5, the irradiation position of the laser beam and the maximum light amount are calculated (S5).

When the lens barrel 2 reaches the predetermined final movement position (S6), the laser beam irradiation position is corrected to the predetermined irradiation position based on the laser beam irradiation position calculated as described above. The moving amount and moving direction of the collimator lens necessary for the calculation are calculated, and the lens barrel 2 is moved by the lens barrel moving unit 8 in a direction perpendicular to the optical axis of the laser beam according to the calculated moving amount and moving direction. To adjust the irradiation position of the laser beam (S
7).

Subsequently, contrary to the above, the lens barrel 2 is moved from the final movement position to the initial movement position (S8). At this time, similarly to the above, it is monitored whether or not the lens barrel 2 has passed a predetermined measurement point (S9), and T is determined at regular intervals.
The laser beam is captured by the V camera 4, and the maximum light amount of the laser beam is calculated by the image processing device 5 (S1).
0).

When the lens barrel 2 reaches the initial movement position (S1)
1), as shown in FIG. 3, the same at the time of the outward movement (that is, at the time of movement from the movement initial position to the movement final position) and at the time of the backward movement (that is, at the time of movement from the movement final position to the movement initial position) The light amount value of the laser beam at the measurement point is averaged by the host computer 6 to obtain the lens barrel 2
Calculate the relationship between the amount of movement of the laser beam and the light amount of the laser beam,
The focus position is calculated from the maximum light amount value (S12).
Thereby, the same focus position as when the output light amount of the laser beam is stabilized is calculated. Finally, based on the calculated focus position, the laser beam emission optical unit 1
The fixing position of the lens barrel 2 with respect to the holder is determined, the lens barrel moving unit 8 is operated via the controller 7, and the lens barrel 2 is fixed.
Is moved to the fixed position to adjust the focus position (S1).
3). As described above, the laser beam emitting optical unit 1
Is completed.

The inspection of whether the laser beam irradiation position and the focus position of the laser beam emission optical unit 1 adjusted as described above are within a predetermined standard is performed by adjusting the lens barrel 2 after the focus position adjustment. The laser beam emitting optical unit 1 of the finished product, which is adhered and fixed to the holder, emits light again, and the TV camera 4 is moved by the TV camera moving stage 9 to measure the light amount of the laser beam in the same manner as when adjusting the focus position. Do. From the result, the irradiation position and the focus position are calculated, and it is checked whether each position is within a predetermined standard.

As described above, according to the present embodiment, even before the output of the laser beam is stabilized, the fetched light amount value is averaged to obtain the same value as when the output of the laser beam is stabilized. Since the irradiation position and the focus position of the laser beam are measured, the focus position of the laser beam can be measured in a short time and with high accuracy without being affected by fluctuations in the output of the laser beam. Further, since the measured focus position is prevented from being deviated from the focus position when the output of the laser beam is stabilized, the production efficiency of the laser beam emitting optical unit can be improved.

In addition, by adjusting the irradiation position of the laser beam before measuring and adjusting the focus position, in addition to the measurement of the focus position of the laser beam, the measurement of the irradiation position of the laser beam and the adjustment of the irradiation position are performed in a series. Since the adjustment is performed in the adjustment step, the adjustment man-hour of the laser beam emission optical unit can be reduced.

In the above description, the case where the lens barrel 2 is moved in the optical axis direction of the laser beam when measuring the irradiation position and the focus position of the laser beam has been described as an example. Even when the TV camera 4 is moved in the optical axis direction of the laser beam, the measurement of the irradiation position of the laser beam and the measurement of the focus position can be similarly performed.

In the above-described embodiment, the irradiation position of the laser beam is adjusted after the forward movement is completed. However, when the calculation of the irradiation position is completed, the lens barrel 2 moves in the optical axis direction of the laser beam. Even in the middle, it may be moved in a direction orthogonal to the optical axis direction. As a result, the movement time lag to the return movement can be eliminated, and the adjustment of the laser beam emitting optical unit 1 can be speeded up.

Further, in the present embodiment, the moving speed of the lens barrel 2 at the time of the focus adjustment is twice the conventional speed, but the moving speed may be determined in consideration of the accuracy of the focus calculation and the adjustment time. It is not limited to.

In the present embodiment, the amount of light is detected by reciprocating the lens barrel 2. However, the moving speed of the lens barrel 2 is further increased so that the movement of the lens barrel 2 for capturing a laser beam is reduced. The configuration may be performed three or more times.

[0042]

As described above, the method for measuring the focus position of the laser beam emitted from the laser beam emitting optical unit according to the present invention comprises the steps of emitting the laser beam from the laser beam emitting optical unit, A step of repeatedly capturing the light intensity of the laser beam at the measurement point set for each, and a corridor that maximizes the light intensity of the laser beam based on the distribution calculated after averaging the light intensity of the captured laser beam. Calculating the position of the meter lens, so that the focus position of the laser beam is measured in the same manner as when the output of the laser beam is stable, so that the focus position of the laser beam can be shortened without being affected by the output fluctuation of the laser beam. Measurement can be performed with high accuracy in time.

Further, after the step of emitting the laser beam from the laser beam emitting optical unit, while moving the collimator lens in the direction of the optical axis of the laser beam, the laser beam at the measurement points set at regular intervals is moved. Capturing the light amount value, calculating the irradiation position of the laser beam based on the distribution of the light amount value of the captured laser beam, and setting the irradiation position of the laser beam to a predetermined position based on the calculated irradiation position of the laser beam. Calculating the movement amount and movement direction of the collimator lens necessary to correct the irradiation position, and moving the collimator lens according to the calculated movement amount and movement direction, thereby measuring the focus position of the laser beam. In addition to laser beam irradiation position measurement and Since the irradiation position adjustment is performed in a series of adjustment processes can be reduced man-hours for adjusting the laser beam emitting optical unit.

The method for adjusting the focus position of the laser beam emitted from the laser beam emitting optical unit of the present invention is a method for adjusting the focus position of the laser beam emitted from the laser beam emitting optical unit of the present invention. Measuring the focus position of the laser beam emitted from the emission optical unit;
Moving the collimator lens to the measured focus position of the laser beam, so that the focus position of the laser beam can be adjusted in a short time with high accuracy, and the measured focus position and the output of the laser beam Since the shift from the focus position at the time of stabilization is prevented, the production efficiency of the laser beam emitting optical unit can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an adjustment device for adjusting a laser beam irradiation position, a focus adjustment, and an inspection of a laser beam emission optical unit.

FIG. 2 is a flowchart illustrating an adjustment process of the laser beam emitting optical unit according to the embodiment.

FIG. 3 is a graph showing a relationship between a movement position of a lens barrel and a light amount value of a laser beam.

FIG. 4 is a perspective view showing a schematic configuration of a laser scanning optical system in a conventional laser beam printer.

FIG. 5 is a sectional view showing a laser beam emitting optical unit in the laser scanning optical system shown in FIG.

6 is a schematic configuration diagram showing an adjustment device for adjusting a laser beam irradiation position, a focus adjustment, and an inspection in the laser beam emission optical unit shown in FIG. 5;

FIG. 7 is a graph showing a relationship between a movement position of a lens barrel and a light amount value of a laser beam.

FIG. 8 is a graph showing the relationship between the movement position of the lens barrel and the light amount of the laser beam immediately after the power supply to the semiconductor laser light source is turned on and when the output of the laser beam is stabilized.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser beam emission optical unit 2 lens barrel 3 laser driver 4 TV camera 5 image processing device 6 host computer 7 controller 8 lens barrel movement unit 9 TV camera movement stage 10 adjustment device for laser beam emission optical unit

Claims (5)

[Claims] 1. A laser beam is emitted from a laser beam emitting optical unit having a laser light source unit for irradiating laser light, and a collimator lens for forming a laser beam by converting the laser beam emitted from the laser light source unit into parallel light. A method for measuring a focus position of a laser beam, comprising: emitting a laser beam from the laser beam emitting optical unit; and moving an optical axis of the laser beam between a predetermined initial movement position and a final movement position of the collimator lens. While repeatedly moving in the direction, a step of repeatedly capturing the light amount value of the laser beam at measurement points set at regular intervals, and averaging the light amount value of the captured laser beam. The distribution of the laser beam intensity is calculated, and based on the distribution, Calculating the position of the collimator lens at which the light amount value of the laser beam becomes maximum. The method of measuring the focus position of the laser beam emitted from the laser beam emission optical unit. 2. After the step of emitting a laser beam from the laser beam emitting optical unit, while moving the collimator lens from the predetermined initial movement position to the final movement position in the optical axis direction of the laser beam, Capturing a light amount value of the laser beam at a measurement point set at the constant movement interval; calculating an irradiation position of the laser beam based on a distribution of the captured light amount value of the laser beam; Based on the calculated irradiation position of the laser beam,
Calculating a movement amount and a movement direction of the collimator lens necessary to correct the irradiation position of the laser beam to a predetermined irradiation position, and moving the collimator lens according to the calculated movement amount and the movement direction. A focus position measuring method for a laser beam emitted from the laser beam emitting optical unit according to claim 1, comprising: 3. A laser beam is emitted from a laser beam emitting optical unit having a laser light source for irradiating laser light, and a collimator lens for forming a laser beam by converting the laser light emitted from the laser light source into parallel light. A method of measuring a focus position of a laser beam, comprising: emitting a laser beam from the laser beam emitting optical unit; and detecting a light amount of the laser beam between a predetermined movement initial position and a movement end position. Repeating the movement of the laser beam in the optical axis direction while repeatedly capturing the light amount of the laser beam at measurement points set at regular intervals; and averaging the light amount of the captured laser beam. Then, the distribution of the light amount value of the averaged laser beam is calculated. Calculating the position of the collimator lens at which the light amount value of the laser beam becomes maximum based on the distribution. Position measurement method. 4. After the step of emitting a laser beam from the laser beam emitting optical unit, the light amount detecting means for detecting the light amount of the laser beam is moved from the predetermined initial movement position to the final movement position. Capturing the light amount value of the laser beam at measurement points set at the constant movement intervals while moving in the axial direction; and irradiating the laser beam based on the distribution of the light amount value of the captured laser beam. Calculating, based on the calculated irradiation position of the laser beam,
Calculating a movement amount and a movement direction of the collimator lens necessary to correct the irradiation position of the laser beam to a predetermined irradiation position, and moving the collimator lens according to the calculated movement amount and the movement direction. The focus position measuring method for a laser beam emitted from the laser beam emitting optical unit according to claim 3, comprising: 5. A laser beam is emitted from a laser beam emitting optical unit having a laser light source for irradiating a laser beam, and a collimator lens for forming a laser beam by converting the laser beam emitted from the laser light source into parallel light. A method of adjusting a focus position of a laser beam, wherein the laser beam is emitted from the laser beam emitting optical unit by the focus position measuring method of a laser beam emitted from the laser beam emitting optical unit according to any one of claims 1 to 4. Measuring the focus position of the laser beam to be performed; and moving the collimator lens to the measured focus position of the laser beam. Focus position adjustment method.