JPH0720403A - Laser light position controller - Google Patents

Abstract

PURPOSE:To easily enable position control in submicron units. CONSTITUTION:Laser light 10 which is shaped into a parallel beam by a beam shaping part 1 after being transmitted through an optical path displacement plate 2 and reflected by a mirror 3 is reduced and converged on an image formation surface 5 as a fine spot by a light convergence part 4. The optical path displacement plate 2 is formed of a transparent material such as quartz glass in a cuboid shape and its arrangement angle is controlled by an angle control mechanism. When the optical path displacement plate 2 is slanted by an angle DELTAtheta, the laser light is refracted by the optical path displacement plate 2 and displaced by DELTAh in parallel from the optical path formed when an angle thetais zero. The displacement DELTAh is reduced by the light convergence part 4 at a specific reduction rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam position control device, and more particularly to a laser beam position control device capable of minutely controlling the position of a laser beam on an image plane.

[0002]

2. Description of the Related Art Conventionally, as a method of controlling the position of a laser beam on an image plane, a method of reflecting the laser beam by a mirror and controlling the angle of this mirror, for example, JP-A-2-69 is known.
As disclosed in Japanese Patent No. 713, there is a method in which a prism in which the position of incident light and the position of emitted light are displaced is arranged on the optical path, and this prism is driven by a piezo translator or the like.

[0003]

In the former method described above, since the position change of the laser beam with respect to the angle change of the mirror is large, a minute angle control is required to perform a minute position control. However, it is extremely difficult to control the position of the sub-micron unit by controlling the mirror angle minutely and stably.

In the latter method, minute position control is possible, but the prism needs to be driven by a piezo translator, etc., which not only complicates drive control, but also has a problem in stability.

An object of the present invention is to provide a laser beam position control device which can easily realize position control in submicron units by taking advantage of the above two methods.

[0006]

SUMMARY OF THE INVENTION A laser beam position control device of the present invention includes an optical path displacement plate for displacing emitted light in parallel to incident light when the arrangement angle is changed, and an emitted light from the optical path displacement plate. A light condensing unit that reduces the light at a predetermined reduction ratio and condenses the light on the image plane.

Further, the laser beam position control device of the present invention is
An optical path deflector that deflects the emitted light by a predetermined angle with respect to the incident light when the arrangement angle is changed, an optical path corrector that receives the emitted light of the optical path deflector and corrects it in a predetermined direction, and an output of the optical path corrector. And a light condensing unit that condenses the emitted light at a predetermined reduction ratio and condenses it on the image plane.

[0008]

The present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.
The structure of an optical system is shown. Here, the laser beam 10 shaped into a parallel beam by the beam shaping unit 1 passes through the optical path displacement plate 2 and is reflected by the mirror 3, and then is condensed by the condensing unit 4.
Thus, it is reduced at a predetermined reduction ratio and condensed as a minute spot on the image plane 5.

The optical path displacement plate 2 is arranged on the optical path, and the arrangement angle is controlled by an angle control mechanism (not shown). The angle control mechanism holds the optical path displacement plate 2 having a rotation axis orthogonal to the optical path, and drives the rotation axis by a pulse motor to change the angle of the optical path displacement plate 2.

The optical path displacement plate 2 is formed of a transparent material such as quartz glass into a rectangular parallelepiped. When the optical path displacing plate 2 faces the laser light, that is, when the angle θ of the optical path displacing plate 2 is 0, the laser light travels straight and the optical path is not displaced. When the optical path displacing plate 2 is tilted by an angle Δθ, the laser light is refracted by the optical path displacing plate 2, and the optical path is Δ when the angle θ of the optical path displacing plate 2 is 0.
It is displaced in parallel by h and emitted.

When the laser beam is displaced in parallel by changing the arrangement angle of the optical path displacement plate as described above, the position change of the laser beam spot on the image plane 5 is determined by the reduction magnification of the converging unit 4. . Now, for example, the reduction ratio is 1/5
If the displacement Δh when the angle θ of the optical path displacement plate 2 is 20 ° is 1 mm, the position change of the laser light spot is 2 μm (1/500 mm). Therefore, in order to move the position of the laser beam spot by 2 μm, the angle of the optical path displacement plate 2 may be changed by 20 °. In this case, the rotation step of the pulse motor for changing the angle of the optical path displacement plate 2 is 2
If the rotation angle is 10 °, the rotation is performed by 20 ° in 10 steps, so that it is possible to perform position control in submicron units of about 0.2 μm per step.

Since the relationship between the angle θ and the displacement Δh is not linear but constant, the rotation control of the pulse motor may be carried out while correcting. The relationship between the angle θ and the displacement Δh also changes depending on the thickness of the optical path displacement plate 2.

FIG. 2 shows another embodiment of the present invention.

Here, an optical path deflecting plate 6 and an optical path correcting plate 7 are provided in place of the optical path displacing plate 2 shown in FIG.
Here, the optical path deflecting plate 6 is arranged on the optical path, and the arrangement angle is controlled by an angle control mechanism (not shown). Further, the optical path correcting plate 7 is arranged to deflect the laser light transmitted through the optical path deflecting plate 2 toward the mirror 3.

The optical path deflecting plate 6 is a transparent plate made of quartz glass, and the emitted light has a certain angle difference with respect to the incident light. Further, when the angle of the optical path deflecting plate 6 is inclined by Δθ, it is formed so as to be deflected by Δθ with respect to the optical path when it is not inclined and emitted.

The optical path correcting plate 7 is a transparent plate made of quartz glass, and corrects the laser light deflected by the optical path deflecting plate 2 so as to be directed to the mirror 3. In this case, the incident position and the incident angle of the incident light on the optical path correcting plate 7 are
Since it changes depending on the arrangement angle of the optical path deflecting plate 6, the emitted light of the optical path correcting plate 7 is subjected to the displacement and deflection of the optical path at the same time as in the case where the arrangement angle of the optical path deflecting plate 6 is not changed. Even with this configuration, the same effect can be obtained.

[0018]

As described above, according to the present invention, an optical path displacing plate that displaces emitted light in parallel to incident light when the arrangement angle is changed is provided, and the angle of this optical path displacing plate is controlled. By irradiating the image-forming surface with a predetermined reduction ratio by the light condensing unit 4, it is possible to easily realize position control in submicron units without the need for minute angle control and complicated drive control as in the past. it can.

Further, an optical path deflector formed so as to emit an incident light with a certain angle difference when the angle is changed,
Also, even if an optical path correcting plate for correcting the direction of the light deflected by the optical path deflecting plate is provided, similarly, position control in submicron units can be easily realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

 2 Optical path displacement plate 4 Converging part 5 Image plane 6 Optical path deflection plate 7 Optical path correction plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Ueda 4-3-14 Sagamihara, Sagamihara-shi, Kanagawa Nippon Electric Laser Equipment Engineering Co. Ltd.

Claims (2)

[Claims] 1. An optical path displacement plate for displacing emitted light in parallel to incident light when the arrangement angle is changed, and the emitted light of the optical path displacement plate is reduced at a predetermined reduction ratio and collected on an image plane. A laser beam position control device, comprising: a condensing unit that emits light. 2. An optical path deflecting plate for deflecting outgoing light by a predetermined angle with respect to incident light when the arrangement angle is changed, and an optical path correcting plate for receiving outgoing light from the optical path deflecting plate and correcting it in a predetermined direction. A laser beam position control device, comprising: a light condensing unit that reduces the light emitted from the optical path correction plate by a predetermined reduction ratio and condenses the light on the imaging surface.