JP3517262B2 - Optical axis adjusting device and optical axis adjusting method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis adjusting device and an optical axis adjusting method for accurately aligning a laser optical path with a lens optical axis in order to sufficiently use the condensing characteristics of a lens.

[0002]

2. Description of the Related Art A conventional optical axis adjusting method will be described.

FIG. 5 shows a schematic view of an optical system for realizing the first conventional optical axis adjusting method. In FIG. 5, reference numeral 2 is a laser beam, 19 is a laser, 20 is a lens mounted on a stage 20A capable of adjusting parallel translation in two directions and rotation of two axes, and 21 is an irradiation position of the laser beam 2. Is a target for.

In the optical axis adjustment in the first conventional example, the laser 19 is driven to pass the laser beam 2 through a desired optical system in advance. At that time, the lens 20 whose optical axis should be aligned is not inserted, and the laser light 2 is allowed to fly far enough. In addition, the target 21 prepared at a distance
A mark is made on the irradiation position of the laser beam 2 before the insertion of the lens 20.

Next, the lens 20 is inserted so that the laser irradiation position does not deviate from the mark on the target 21. When the lens 20 is inserted as described above, the incident position of the laser light 2 on the lens 20 and the inclination of the lens 20 are adjusted by moving and rotating the lens 20 itself by the adjusting mechanism of the stage 20A.

Next, FIG. 6 shows a schematic diagram of an optical system for realizing the second conventional optical axis adjusting method. In FIG.
Reference numeral 22 is a screen provided with an opening 22a, and 23 is light reflected from the lens surface.

The optical axis adjusting method according to the second conventional example uses the reflected light from each surface of the lens, and in the adjustment, first, the laser light 2 is passed through a desired optical system.

Next, the lens 20 whose optical axes should be aligned
Is inserted so that its optical axis substantially coincides with the laser optical path. A screen 22 having an opening 22a larger than the beam diameter of the laser light 2 is provided at a position before entering the lens 20 so that the laser light 2 passes through the opening 22a.

As described above, when the screen 22 is installed in front of the lens 20, the laser light 2 that has passed through the opening 22a of the screen 22 is reflected as an incident beam on each surface of the lens 20, and the reflected light 23 is reflected by the screen 22. Reflected on the top.
The reflected light 23 from each surface of the lens overlaps the incident beam, that is, the opening 2 of the screen 22.
The position and angle of the lens 20 are adjusted so as to match 2a.

Also, instead of using each of the reflected lights as an adjusting beam, the diffraction pattern formed by the reflected lights is used to perform adjustment so as to overlap the incident beam light as described above.

[0011]

However, such a conventional optical axis adjusting method has the following problems.

First, in the case of the first conventional example, the conditions under which the optical axis adjustment can be performed are very limited. When it is not possible to take a sufficiently long distance behind the insertion position of the lens 20 due to the optical system, or when it is necessary to insert the lens 20 having a very short focal length, the laser is placed at a far position behind the lens 20. Since the target 21 for marking the irradiation position of the light 2 cannot be arranged,
The optical axis cannot be adjusted by the adjusting method of Conventional Example 1.

Further, in the method of the conventional example 1, the optical axis of the lens 20 is adjusted by changing the irradiation position of the laser light 2 on the target 21 at a distance, but the beam of the laser light 2 is transmitted at a distance after passing through the lens. The diameter is considerably enlarged, and the change in the irradiation position on the target 21 due to the difference in the incident position and the incident angle of the laser beam 2 on the lens 20 is hard to discern.

Also in the method of the second conventional example, when the reflected light 23 is adjusted so as to coincide with the incident beam, the coincident point actually hits the opening 22a of the screen 22 and the opening 22a thereof. Since the diameter of the beam is also larger than the beam diameter, it can be said that it is impossible to finely adjust the optical axis within the opening 22a.

In particular, when the surface of the lens 20 is subjected to a treatment such as an antireflection film in order to improve the light transmission efficiency, the intensity of the reflected light 23 becomes small, so that the optical axis adjustment is further performed. There is also a problem that it becomes difficult.

Further, as a problem common to the conventional example 1 and the conventional example 2, there is a problem of adjustment accuracy.

In particular, when using a lens designed to collect light up to the diffraction limit with respect to the wavelength of the recording light, such as an objective lens for producing an optical disk master, there is a serious problem. That is, such an objective lens is generally used as a compound lens, but since the compound lens is designed to have a small field of view in order to make the beam spot smaller, a slight deviation of the recording light from the lens optical axis is caused. On the other hand, the light condensing characteristic becomes extremely low. Therefore, it is necessary to align the optical axis of the lens with the optical path of the laser with extremely high accuracy, but such alignment becomes difficult.

As described above, both the method of the conventional example 1 and the method of the conventional example 2 have a big problem in terms of the adjustment accuracy of the optical axis. In addition, when adjusting the optical axis, the adjuster is required to make a judgment that "the target irradiation position does not change" or "is passing through the center of the opening", but this judgment depends on the adjuster. It is considered that there are individual differences among coordinators, and there was a problem in terms of the objective reliability and stability of coordination.

In view of the above problems of the prior art, it is an object of the present invention to provide an optical axis adjusting device and an optical axis adjusting method capable of accurately aligning a laser optical path with an optical axis of a lens.

[0020]

Optical axis adjustment device according to claim 1 according to the present invention SUMMARY OF] includes a lens, the Le behind the lens
Means for changing the distance between the optical axis of the lens and a reflecting plate arranged perpendicularly, and means for changing the direction of incidence of the laser light on the lens into at least a biaxial tilt direction and at least a biaxial parallel movement direction, It is characterized by comprising means for separating the reflected light from the reflection plate that has passed through the lens from the incident light, and means for detecting the reflected light.

The optical axis adjusting device according to claim 2 of the present invention is
A compound lens is used as the lens ,
1 is an optical axis adjusting device.

An optical axis adjusting device according to a third aspect of the present invention is
As means for changing the distance between the reflecting plate and the lens, characterized in that it uses a movable stage for displacing the lens mounting the lens to the lens optical axis direction parallel to claim 1 or 2 The optical axis adjusting device described
It

An optical axis adjusting device according to a fourth aspect of the present invention is
As means for changing the distance between the reflecting plate and the lens, and mounting the lens, that by using an actuator for displacing the lens in the lens optical axis direction parallel by applying a periodically changing voltage The optical axis adjusting device according to claim 1 or 2.

An optical axis adjusting device according to a fifth aspect of the present invention is
As means for changing the translation direction of the at least two axial and tilt direction of the at least two axial direction of incidence of the laser beam relative to the lens, a least mutually perpendicular which is positioned before incidence of the laser light to the lens 5. A biaxial translation mechanism and a tilt adjustment mechanism having two axes of rotation perpendicular to each other are provided , and any one of claims 1 to 4 is provided. Optical axis adjustment device described
It is a place.

The optical axis adjusting device according to claim 6 of the present invention is
6. The translation mechanism according to claim 5, wherein a lens mounted on a biaxial movable stage is used as the parallel movement mechanism.
It is a mounted optical axis adjusting device.

The optical axis adjusting device according to claim 7 of the present invention is
Characterized in that it uses a two-dimensional diode array as means for detecting the reflected light, of claims 1-6 Neu
The optical axis adjusting device according to the first aspect.

The optical axis adjusting device according to claim 8 of the present invention is
As a means for detecting the reflected light, a condenser lens and
The one in which a two-dimensional diode array is installed on the focal plane of the condenser lens is used .
The optical axis adjustment device according to any one of items 6 to 6.

The optical axis adjusting device according to claim 9 of the present invention is
Based on the signal received by the two-dimensional diode array
Characterized in that it comprises a signal processing unit for creating displacement signal and the rotation symmetry error signal intensity distribution peak position of the relative change in the distance between the reflecting plate and the lens,請
The optical axis adjusting device according to claim 7 or 8.

According to claim 10 of the present inventionOptical axis adjustment method
Is a method of aligning the laser optical path with the optical axis of the lens.
Change the distance between the lens and the reflector near the focal length of the lens.
The reflected light to the detection means at all positions.
The incident position does not change and the intensity distribution is always rotationally symmetrical
Change the incident direction of light to the objective lens so that it takes a distribution
It is characterized by that.

[0030]

[0031]

[0032]

According to the optical axis adjusting device of the first aspect, the following actions can be obtained.

First, consideration will be given to the change in position on the reflected light detecting means when the laser light is obliquely incident on the lens. Considering the laser light as a light beam, the light reflected from the reflection plate always enters the lens obliquely. At this time, if the distance between the lens and the reflection plate is changed, the reflection position on the reflection plate changes, and the position at which the reflected light is incident again changes accordingly. However, since the angle of re-incident light is constant at this time, the optical path after exiting the lens changes, and as a result,
The irradiation position on the reflected light detection means changes.

Next, regarding the rotational symmetry of the intensity distribution, in this case, to facilitate understanding, it is considered that the laser light is a bundle of light rays. Further, the "distance between the light ray and the optical axis of the lens" is defined as the distance between the light beam passing position on the front focal plane of the lens and the front focal point.

Considering the behavior of the ray group after passing through the lens,
The farther the ray group is from the optical axis of the lens, the larger the angle of incidence on the focal plane. From this, it can be seen that in the vicinity of the focal point, the farther from the lens optical axis, the smaller the angle formed by the light rays within the light group, and the greater the intensity per unit area. As a result, when the light is obliquely incident, the incident beam on the reflected light detecting means is not rotationally symmetrical.

By changing the distance between the lens and the reflecting plate, the above phenomenon, that is, the change of the irradiation position of the reflected light on the reflected light detecting means and the deviation from the rotational symmetry of the intensity distribution do not occur at any distance. At this time, the laser optical path and the lens optical axis match. By adjusting the position of the lens and the incident direction so as to be so, the laser optical path can be aligned with the lens optical axis. That is, reflected light
Of irradiation position and rotation pair of intensity distribution with respect to detection means
The position of the laser optical path with respect to the lens optical axis due to the change of the name
Deviation and angular deviation are detected, and the
-By changing the incident direction of laser light in two tilting directions
Change the direction of laser light incidence in two parallel translation directions.
Corrects misalignment and angular misalignment by combining with
The laser optical path to the lens optical axis with high accuracy.
You can As a result, the condensing characteristics of the lens are sufficient
Can be demonstrated.

In the optical axis adjusting device of the second aspect, it is clarified that a compound lens is often used as the lens in order to reduce the spot of the laser light.

In the optical axis adjusting device of the third aspect, the lens is mounted on the movable stage, and the lens is displaced in the direction parallel to the optical axis of the lens by the operation of the movable stage to change the distance between the lens and the reflector. .

In the optical axis adjusting device according to a fourth aspect of the present invention, a lens is mounted on the actuator, and a voltage that changes periodically is applied to the actuator to constantly displace the lens, thereby keeping the distance between the lens and the reflecting plate. Since it constantly changes automatically, the work of aligning the laser optical path with the lens optical axis can be performed efficiently.

In the optical axis adjusting device of the fifth aspect, the incident direction of the laser light on the lens is changed by translating the reflecting surface at the position before the incidence of the lens in the two vertical directions or by rotating about the two vertical axes. Let

In the optical axis adjusting device of the sixth aspect, the biaxial movable stage is operated to move the lens in parallel in two vertical directions.

[0042]

In the optical axis adjusting device of the seventh aspect , since the reflected light is detected by the two-dimensional diode array, the change of the irradiation position on the reflecting plate through the lens is measured as the deviation from the rotational symmetry of the intensity distribution. You can

[0044] In the optical axis adjustment device according to claim 8, the use condenser lens in front of the two-dimensional diode array is provided, the focal point of the condenser lens is to come on a two-dimensional diode array, similar to the microscope system Since this optical system is used, the shape of the beam condensed by the condenser lens can be approximately magnified and observed, and more precise adjustment is possible.

[0045]

In the optical axis adjusting device according to the ninth aspect , the signal processing unit creates the displacement signal of the intensity distribution peak position and the rotational symmetry error signal based on the signal received by the two-dimensional diode array, and shifts them. To measure.

In the optical axis adjusting method of the tenth aspect , the incident direction is adjusted so that the incident position of the reflected light on the detecting means does not change and the intensity distribution is rotationally symmetric, so that the laser optical path is obtained. The optical axis of the lens can be matched.

[0048]

The present invention will be described in detail below with reference to specific examples.

(Embodiment 1) As Embodiment 1, a case where an ultraviolet laser beam is accurately passed through one convex lens will be described.

FIG. 1 schematically shows an optical system for realizing the optical axis adjusting method according to the first embodiment of the present invention. In FIG. 1, 1 is an ultraviolet laser, 2 is a laser beam, 3 and 4 are mirrors for changing the laser optical path, 5 is a polarization beam splitter (PBS), 6 is a quarter wavelength plate, 7 is a convex lens, and 8 is A reflector installed so as to be perpendicular to the optical axis of the convex lens 7, 9 is a CCD camera as a two-dimensional diode array for receiving reflected light, and 10 is a monitor for displaying the light received by the CCD as an image Is. The mirrors 3 and 4 are respectively parallel movement and tilt adjustment mechanism 3
A and 4A are provided, and the optical path of the laser light 2 is changed by them to adjust the incident position and angle of the laser light 2 on the convex lens 7. The convex lens 7 is mounted on a uniaxial stage 7A that can move in a direction parallel to the lens optical axis.

First, the reflection plate 8 is installed near the focal position of the convex lens 7 by a mechanical method or the like so as to be perpendicular to the optical axis of the convex lens 7.

Next, the ultraviolet laser 1 is driven to emit the p-polarized laser beam 2, and the laser beam 2 is guided to the convex lens 7 through the mirrors 3 and 4, the polarization beam splitter 5 and the quarter wavelength plate 6. . The laser light 2 that has passed through the convex lens 7 is reflected by the reflector 8
After being reflected by and passing through the convex lens 7 again,
The light passes through the wave plate 6, is reflected by the polarization beam splitter 5, and enters the CCD camera 9. Light incident on the CCD camera 9 is displayed on the monitor 10, and adjustment is performed while watching it.

The adjustment procedure is as follows when the distance between the convex lens 7 and the reflecting plate 8 is changed in the vicinity of the focal length of the convex lens 7.
Any method may be used as long as it can be adjusted so that the incident position of the reflected light on the detection optical system does not change at all positions and the intensity distribution is always rotationally symmetrical, but an example is shown below.

First, the reflection plate 8 is brought to the focal position of the convex lens 7, and rough adjustment is performed so that the image on the monitor 10 is substantially rotationally symmetrical at that position.

Next, while changing the distance between the convex lens 7 and the reflecting plate 8, the uniaxial parallel movement of the mirror 4 and the corresponding tilt are used so that the irradiation position does not move in the adjusting direction and the intensity distribution. Make a fine adjustment so that is always symmetrical.

Next, fine adjustment is similarly performed on the axis in the direction perpendicular to the direction adjusted above. In this case, the mirror 3,
Adjust according to the tilt of 4.

After the above adjustment, the reflecting plate 8 is brought to the focal point of the convex lens 7 and the beam spread in each direction is adjusted while changing the distance between the convex lens 7 and the reflecting plate 8 before and after that. Compare. Adjustment is performed by the mirrors 3 and 4 until the spread becomes similar.

As described above, according to this embodiment, the laser optical path can be accurately aligned with the lens optical axis.

If the optimum position cannot be found by this method, it is considered that there is a problem in the adjustment of the reflection plate 8, so it is necessary to adjust the reflection plate 8 again.

(Embodiment 2) Next, as a second embodiment, description will be given of a case where a recording laser beam is passed through an objective lens mounted in advance in an optical disk master manufacturing apparatus.

FIG. 2 schematically shows an optical system for realizing the optical axis adjusting method according to the second embodiment of the present invention. In FIG. 2, 11 is a beam expander, 12 is an objective lens (NA 0.9, focal length 2 mm), 13 is a glass disk master used as a reflector, and 14 is a CCD camera 9.
Condensing lens (focal length 2000m
m). The other components are the same as those in FIG. That is, 1 is an ultraviolet laser, 2 is a laser beam, 3 is a mirror, 5 is a polarization beam splitter, 6 is a quarter wavelength plate, and 9 is a
Is a CCD camera, and 10 is a monitor.

The laser beam 2 emitted from the ultraviolet laser 1 by the beam expander 11 has a diameter of about 7 mm.
It is shaped into parallel light. The mirror 3 is mounted on the movable stage 3A so that the tilt of the two axes can be adjusted, and the objective lens 12 is mounted on the movable stage 12A so that the objective lens 12 can be translated in two directions perpendicular to each other. In this embodiment, the incident position and angle of the laser beam 2 on the objective lens 12 are adjusted by the tilting 2 axis of the mirror 3 and the parallel movement 2 axis of the objective lens 12. Further, the CCD camera 9 is provided on the focal plane of the condenser lens 14.
Install so that the light-receiving surface of is.

The adjusting method will be described below.

First, the laser light 2 emitted from the ultraviolet laser 1 is dropped through the beam expander 11, the polarization beam splitter 5, the quarter-wave plate 6 and the mirror 3 so as to pass through the vicinity of the center of the objective lens 12. . Next, the objective lens 12 is moved closer to the glass disk master (reflecting plate) 13. Since the optical system is the same as that of the first embodiment, the reflected light from the glass disk master 13 is received by the CCD camera 9, but in the case of this embodiment, the distance between the objective lens 12 and the glass disk master 13 is large. As the focal length of the objective lens 12 approaches, a beam image focused by the focusing lens 14 is projected on the monitor 10. This image is the beam shape actually condensed near the glass disk master 13 magnified 1000 times. In reality, it cannot be said that the beam shape is faithfully reproduced due to the eclipse by the objective lens 12, but there is no problem in evaluating the peak position of the intensity distribution and the rotational symmetry. From this, adjustment is performed while observing this image.

Basically, the adjustment is performed by the same method as in the first embodiment, but the difference from the first embodiment is that when the incident direction of the laser beam 2 is changed, the tilt is moved by the mirror 3 and the parallel movement is performed by the objective lens 12. This is the point to do. Otherwise, the procedure is the same as that of the first embodiment, that is, after coarse adjustment to some extent, fine adjustment is performed for each axis, and finally, adjustment is performed so that the spread in both axis directions becomes uniform.

Compared with the first embodiment, since the condenser lens 14 is provided in front of the CCD camera 9 , the beam on the monitor 10 against the change in the distance between the objective lens 12 and the glass disk master 13 is changed. Since the change in shape is large, it is possible to make more precise adjustment.

As described above, according to the present embodiment, the laser optical path can be accurately aligned with the lens optical axis as in the first embodiment.

(Third Embodiment) Next, as a third embodiment, a case where a recording laser beam is passed through an objective lens mounted in advance in an optical disk master manufacturing apparatus will be described as in the second embodiment.

FIG. 3 schematically shows an optical system for realizing the optical axis adjusting method according to the third embodiment of the present invention. 3 is almost the same as FIG. 2 except that the objective lens 12 is different.
An actuator 15 for moving the lens in parallel with the optical axis,
Sine wave generator 1 for driving actuator 15
6. A two-dimensional diode array 17 capable of monitoring the intensity signal of each element instead of the CCD camera, and a signal processing section 18 for creating various error signals from the intensity signal of each element
Is. In addition, 1 is an ultraviolet laser, 2 is a laser beam, 3 is a mirror, 3A is a movable stage with biaxial tilt, 5 is a polarization beam splitter, 6 is a quarter wavelength plate, 11 is a beam expander, and 13 is a glass disc master. , 14 are condenser lenses.

The adjustment method will be described below.

The difference between the present embodiment and the second embodiment is that in the second embodiment, the detected signal is displayed as an image on the monitor 10 and adjustment is performed while observing it, whereas in the present embodiment, the detection is performed. This is the point that the displacement signal at the intensity distribution peak position and the rotational symmetry error signal are created from the obtained signal by signal processing, and adjustment is performed so that they become zero. Here, the displacement signal is obtained by taking the position where the signal becomes maximum.
The rotational symmetry error signal indicates how much the intensity distribution deviates from rotational symmetry.

In this embodiment, as one method for producing a rotationally symmetric error signal, the two-dimensional diode array 17 is divided into four regions as shown in FIG. Take Then, the difference signal (A-D) of the areas facing each other so as to correspond to the adjustment directions perpendicular to each other
And (BC) are error signals. In this case, since the error signal is obtained in each adjustment direction, each axis is adjusted so that the two error signals become zero.

Similar to the second embodiment, after the laser light 2 is dropped so as to pass near the center of the objective lens 12, the objective lens 12 is moved closer to the glass disk master 13. After approaching to the focal position, a sine wave generator 16 applies a sine wave current having a period of about 1 second to the actuator 15, and the objective lens 12 is moved up and down to move the objective lens 12
The change in the error signal is observed while changing the distance between the glass disc master 13 and the glass disc master 13 up and down. The specific adjustment procedure is exactly the same as that of the first and second embodiments, and it may be adjusted so that the displacement signal and the rotational symmetry error signal become zero.

In the case of observing the difference in the divergence of the beam in the two directions more strictly as the final adjustment, FIG.
As shown in (b), the sum is calculated only in the area limited to a quarter circle in each area, and the sum signals (A '+ D') and (B '+ C) of the areas facing each other corresponding to the adjustment direction are obtained. ′) Create. This shows the extent of spread in each adjustment direction due to the change in the distance between the objective lens 12 and the glass disk master 13.

By differentiating and comparing these two signals, it is possible to observe the difference in how the beams spread in the two directions, and it is sufficient to adjust them so that they are equal.

As described above, according to the present embodiment, the laser optical path can be accurately aligned with the lens optical axis as in the first and second embodiments.

The present invention has been described in detail by the embodiments 1, 2 and 3. The method of changing the vertical distance between the lens and the reflector is mechanically performed by the uniaxial stage in Examples 1 and 2, and electrically by the sine wave generator in Example 3. The principle is the same regardless of which method is used.

The parallel movement of the two axes is the same whether the lens is moved in parallel or the optical path is moved by a mirror, and all adjustment methods can be used for all the embodiments. it can.

[0079]

According to the optical axis adjusting device of the first aspect, the laser
The optical path can be matched with the lens optical axis with high accuracy.

According to the optical axis adjusting device of the second aspect, it is possible to further reduce the spot of the laser light and improve the accuracy by using the assembled lens as the lens.

According to the optical axis adjusting device of the third aspect, in order to change the distance between the lens and the reflecting plate, it is possible to employ a means of mounting the lens on the movable stage, which has a relatively simple structure and is easy to operate. .

According to the optical axis adjusting device of the fourth aspect, since the cyclically changing voltage is applied to the actuator in which the lens is mounted, the distance between the lens and the reflecting plate is automatically and periodically changed with a constant amplitude. can and Turkey, can be efficiently performed to match the laser beam path and the lens optical axis.

According to the optical axis adjusting device of the fifth aspect, the change of the incident direction with respect to the lens can be realized by a relatively simple means such as parallel movement of the reflecting surface in two vertical directions and rotation about the two vertical axes. it can.

According to the sixth aspect of the optical axis adjusting device, since the biaxial movable stage is used to move the lens in parallel in the two vertical directions, the structure can be further simplified and the operation can be simplified. You can

[0085]

According to the optical axis adjusting device of claim 7 , the change of the irradiation position on the reflection plate through the lens and the measurement of the deviation from the rotational symmetry of the intensity distribution can be realized by a single component called a two-dimensional diode array. You can

According to the optical axis adjusting device of the eighth aspect , since the shape of the image formed on the reflection plate by the laser light passing through the lens can be magnified and observed, when the laser light path and the lens optical axis are matched, More precise adjustment is possible.

[0088]

According to the optical axis adjusting device of the ninth aspect , the displacement signal at the peak position of the intensity distribution and the rotational symmetry error signal are created based on the signal received by the two-dimensional diode array. The accuracy of matching can be improved.

According to the optical axis adjusting method of the tenth aspect , the incident direction is adjusted so that the incident position of the reflected light on the detecting means does not change and the intensity distribution is rotationally symmetrical. The laser optical path can be matched with the lens optical axis with high accuracy.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an apparatus for realizing an optical axis adjusting method according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of an apparatus for realizing an optical axis adjusting method according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram of an apparatus for realizing an optical axis adjusting method according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a method of area division for producing each signal in the third embodiment.

FIG. 5 is a schematic diagram showing an optical axis adjustment method of Conventional Example 1.

FIG. 6 is a schematic view showing an optical axis adjusting method of Conventional Example 2.

[Explanation of symbols]

1 ... UV laser 2 ... Laser light 3 ... Mirror 3A ... Parallel movement and tilt adjustment mechanism 4 ... Mirror 4A ... Parallel movement and tilt adjustment mechanism 5 ... Polarizing beam splitter 6 ... Quarter wave plate 7 ... Convex lens 7A ... Uniaxial stage 8 ... Reflector 9 ... CCD camera (two-dimensional diode array) 10 ... Monitor 11 …… Beam expander 12 ... Objective lens 12A ... Movable stage 13 …… Glass disk master (reflector) 14 ... Focusing lens 15: Actuator 16 ... Sine wave generator 17: Two-dimensional diode array 18 ... Signal processing unit

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaji Fujita 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-4-153922 (JP, A) JP-A-5 -189791 (JP, A) JP 3-162721 (JP, A) JP 2-152024 (JP, A) JP 63-153730 (JP, A) JP 51-65947 (JP, A) ) Actual Kaihei 2-132322 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B ^7/ 08-7/22

Claims (10)

(57) [Claims] And 1. A lens, said lens behind the lens
Means for changing the distance between the optical axis of the lens and a reflector arranged perpendicular to the optical axis, and at least 2 in the direction of incidence of laser light on the lens.
Comprising a tilt axis and means for varying the translation direction of the at least two axes, and means for separating the incident light reflected light from the reflecting plate that has passed through the lens, and means for detecting said reflected light An optical axis adjusting device characterized in that 2. The optical axis adjusting device according to claim 1, wherein a compound lens is used as the lens. As claimed in claim 3 wherein the means for varying the distance between the lens and the reflector, characterized in that it uses a movable stage for displacing the lens mounting the lens to the lens optical axis direction parallel, wherein Item 3. The optical axis adjusting device according to item 1 or 2 . 4. As a means for changing the distance between the reflecting plate and the lens, actuator for displacing the lens in the lens optical axis direction parallel by mounting the lens, applying a periodically changing voltage The optical axis adjusting device according to claim 1 or 2, characterized in that. 5. As a means for changing the translation direction of the at least two axial and tilt direction of the at least two axial direction of incidence of the laser beam relative to the lens, is provided at a position before incidence of the laser light to the lens At least the parallel movement mechanism mutually perpendicular two axes was, is characterized in that an adjusting mechanism of the tilt (inclination) having an axis of rotation mutually perpendicular two axes, any one of claims 1 4 Described in
Optical axis adjusting device. 6. A parallel-moving mechanism comprising a biaxial movable stage and a lens mounted thereon.
The optical axis adjusting device according to claim 5 . Characterized in that it uses a two-dimensional diode array as claimed in claim 7 wherein the means for detecting the reflected light, wherein
Item 7. The optical axis adjusting device according to any one of items 1 to 6 . As claimed in claim 8 wherein the means for detecting the reflected light, characterized by using a material obtained by installing the two-dimensional diode array onto the focal plane of the converging lens and the condensing lens, of claims 1-6 The optical axis adjusting device according to any one of 1 . 9. The signal processing unit for creating displacement signal and the rotation symmetry error signal intensity distribution peak position of the relative change in the distance between the reflecting plate and the lens on the basis of the received signal in the two-dimensional diode array 9. The optical axis adjusting device according to claim 7, further comprising: 10. A method for aligning a laser optical path with an optical axis of a lens, wherein a distance between the lens and a reflecting plate is changed in the vicinity of a focal length of the lens, and the incident position of the reflected light on the detecting means is detected at all positions. The optical axis adjusting method is characterized in that the incident direction of light to the objective lens is changed so that the intensity distribution does not change and the intensity distribution is always rotationally symmetrical.