JPH0373914A - Optical axis adjusting device - Google Patents

Abstract

PURPOSE:To easily maintain the accuracy of a photodetector and to improve the accuracy of optical axis adjustment, and to reduce the overall size of the device by adjusting an angle deviation and a position shift for the optical axis adjustment by one photodetector. CONSTITUTION:This device is equipped with the photodetector 16 which is arranged on an ideal optical axis for photodetecting a light beam to be adjusted after it is passed through a convex lens 15 arranged at right angles to the ideal optical axis and a detection driving means 22 which drives the photodetector 16 linearly along the ideal optical axis. When the angle deviation is adjusted, driving control is so performed that the detection surface of the photodetector 16 is positioned at the focus of the convex lens 15, but when only the position shift is adjusted, driving control is so performed that the detection surface of the convex lens 15 is positioned at a specific distance from the focus of the convex lens 15. Therefore, the angle deviation adjustment and position shift adjustment which are required for the optical axis adjustment are performed by using one photodetector 16. Consequently, the accuracy of the photodetector is easily maintained, the optical axis adjustment accuracy is improved, and the device is reduced in size on the whole.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to automatically adjusting the optical axis of a light beam to be adjusted, such as a laser beam, that passes through two points using two mirrors (plane mirrors). The optical axis jl! is aligned with the ideal optical axis passing through the other two points. lRelating to a conditioning device.

(Prior art) Optical axis adjustment in which the optical axis of a light beam to be adjusted, such as a laser beam, passing through two points is aligned with an ideal optical axis passing through two other points is achieved by rotating and adjusting two mirrors. What can be done has been well known for a long time.

Hereinafter, the principle of the front axis adjustment will be explained separately for angle shift adjustment and position shift adjustment.

"Angle Shift Adjustment" This adjustment is an adjustment to create an adjusted light beam having an optical axis parallel to the ideal optical axis, and its basic configuration is shown in FIG. As shown in the figure, the following basic conditions (1) to (2) are required for adjusting the angle deviation.

■ Place the convex lens 2 so that it is perpendicular to the ideal optical axis 1.

■ Install the convex lens 2 so that its center is located on the ideal optical axis 1.

■ Focal length f of lens 2 from the center of convex 1/lens 2
The photodetector 3 is installed at a position separated by

(2) Install the photodetector 3 so that the center of its detection surface is located at the focal point of the convex lens 2.

■ Install the photodetector 3 so that its detection surface is perpendicular to the ideal optical axis 1.

(2) Install the mirror 4 so that its center of rotation is located on the ideal optical axis 1.

Therefore, under the above basic conditions (■ to ■), the angular shift can be adjusted by utilizing the fact that any light beam to be adjusted parallel to the ideal optical axis 1 is imaged as a point at the center of the detection surface of the photodetector 3. It is something to do.

That is, in an optical system that satisfies the above basic conditions, as is clear from FIG. The relationship between the angular deviation (θX, θy) is Δx−ftanθx −(1)Δy
-ftanθy (2).

Therefore, the angular deviation (θX, θy) of the optical axis of the adjusted light beam can be calculated from the displacement (ΔX, Δy) detected by the photodetector 3 using equations (1) and (2) above. Based on this angular deviation (θX, θy), mirror 4 is adjusted to (θ
X/2. By rotating it by θy/2), it is possible to adjust the optical axis of the adjusted light beam to be parallel to the ideal optical axis 1.

Actual angle deviation: In the A adjustment control procedure, errors caused by minute deviations in the configuration based on the basic conditions and the photodetector 3
Due to the detection error, as shown in Fig. 5, so-called eye precision adjustment is used, in which the angular deviation measurement and rotation adjustment of the mirror 4 are repeated until the displacement ΔX falls within a predetermined tolerance range, as shown in Fig. 5. .

"Positional Misalignment Adjustment" This adjustment is an adjustment in which the misalignment with the ideal optical axis is measured after the angular misalignment adjustment, and the misalignment is eliminated from the results.The basic configuration is shown in FIG. As shown in the figure, the following basic conditions (1) to (2) are required for positional deviation adjustment.

■ Install the convex lens 2 so that it is perpendicular to the ideal optical axis 1.

■ Install the convex lens 2 so that its center is located on the ideal optical axis 1.

■ A photodetector 3 is located at a distance from the center of the convex lens 2 by a distance equal to the focal length f of the lens 2 plus a predetermined distance d.
Set up.

(2) Install the photodetector 3 so that the center of its detection surface is located on the ideal optical axis 1.

■ Install the photodetector 3 so that its detection surface is perpendicular to the ideal optical axis 1.

(2) Install the first mirror 4 so that its center of rotation is located on the ideal optical axis 1.

(2) Install the second mirror 5 so that the rotation direction (θ, ψ) matches that of the first mirror 4. (Here, θ is the angle of rotation in a plane parallel to the plane of the paper, and ψ is the angle of rotation in a plane perpendicular to the plane of the paper.) Therefore, in an optical system that satisfies the above basic conditions, as is clear from Fig. 7, The relationship between the displacement (ΔX, Δy) of the image detected by the photodetector 3 from the detection surface center and the positional deviation (Lx, Ly) between the ideal optical axis 1 and the adjusted light beam 6 is L x/f-Δx/d...
・(3>L y / f−Δy/d ・
... is given by (4).

Furthermore, as is clear from Fig. 8, the positional deviation (Lx,
The relationship between Ly) and the rotation angles (θX, θy) of the first and second mirrors 4.5 to eliminate this positional shift is Lxi-? fltanθx −(5
) LV now fl tanθy...
(6) (is the distance M between the rotation centers of the mirrors 4.5).

Therefore, according to the above equations (3) and (5>), the displacement ΔX measured by the photodetector 3 and the mirror 4 for adjusting the positional deviation
．． The relationship between rotation angle θX of 5 is f! tanθx/
It is given by f-Δx/d-(7). Similarly, the mirror 4 for adjusting the displacement Δyε position shift measured by the photodetector 3 using the above equations (4> and (6))
．． The relationship between rotation angle θy of 5 is l tanθy/f
−Δy/d −(8).

Thus, using equations (7) and (8) above, the rotation angles (θX, θy) of the mirrors 4 and 5 are calculated to eliminate the positional deviation of the adjusted light beam from the displacement (ΔX, Δy) measured by the photodetector 3.
is determined, and based on this rotation angle (θX, θy), the second mirror 5 is first rotated by (θx72.θy/2). By ε, the output beam of the second mirror 5 is transferred to the first mirror 4. It can be placed on the center of rotation. Subsequently, by rotating the first mirror 4 by (θX/2.θy/2), it becomes possible to adjust the adjusted light beam 6 while keeping it parallel to the ideal optical axis 1 and eliminating positional deviation.

Even in the actual positional deviation adjustment control procedure, due to errors caused by minute deviations in the configuration based on the basic conditions and detection errors of the photodetector 3, as shown in FIG. A so-called eye-television adjustment is used in which positional deviation measurement and rotational adjustment of the mirrors 4 and 5 are repeated until the deviation is within the range.

FIG. 10 is a schematic diagram of a conventional optical axis adjustment device constructed based on the above-mentioned principle. As shown in the figure, this conventional device has laser beams 11 emitted from laser oscillators 1 and 0.
The second total reflection mirror 12 and the first total reflection mirror 1
3 for total reflection, half mirror 14 to split into two directions,
An angular shift m-aligned photodetector 1 is connected to one side through a convex lens 15.
6, and the other image is formed on a positional deviation adjustment photodetector 18 via a convex lens 17. Here, the first total reflection mirror 13. The convex lens 15 and the angular shift adjustment photodetector 16 are arranged so as to satisfy the basic conditions for angular shift adjustment, and the second total reflection mirror 1
2. The first total reflection mirror 13, the convex lens 17, and the positional deviation adjustment photodetector 18 are arranged so as to satisfy the basic conditions for positional deviation adjustment.

Therefore, first, the detection output of the angular shift adjustment photodetector 16 is taken into the automatic control section 19 consisting of a computer, and the above-mentioned (1) is carried out.
, From equation (2), the angular deviation of the optical axis of the laser beam 11 (θ
X, θy), and based on this angular deviation (θX, θy), the mirror driving device 20 moves the first total reflection mirror 13.
By rotating and adjusting by (θx72.θy/2), the optical axis of the laser beam 11 is adjusted to be parallel to the ideal optical axis.

Next, the detection output of the photodetector 18 for positional deviation adjustment is taken into the automatic control unit 19, and the mirror rotation angle (θX, θy) is calculated. Then, based on this rotation angle (θX, θy), the second total reflection mirror 12 is first rotated by (θx/2.θy/2) by the mirror drive device 21, and then by the mirror drive device 20. By rotating and adjusting the first total reflection mirror 13 by (θx/2.θy/2), the laser beam 11 is adjusted so as to be kept parallel to the ideal optical axis and to eliminate positional deviation.

(Problem to be solved by the invention) However, in the above conventional device, two photodetectors 16
．． 18, it takes time to maintain the accuracy of the detector, which tends to result in a decrease in the precision of adjusting the optical axis: A. Furthermore, since the adjusted light beam is divided into two directions at approximately right angles, space is required, making it difficult to downsize. .

Therefore, the present invention makes it possible to perform the angular shift adjustment and position shift adjustment necessary for optical axis adjustment with a single photodetector, thereby simplifying the maintenance of the accuracy of the photodetector and improving the optical axis adjustment accuracy. The object of the present invention is to provide an optical axis adjustment device that can achieve a high efficiency and reduce the size of the entire device.

[Structure of the invention] (Means and effects for solving the problem) Ideal light whose optical axis of the adjusted light beam is formed at two arbitrary points by arranging a plurality of mirrors and adjusting the rotation of the mirrors. In an optical axis adjusting device for adjusting the optical axis, a convex lens is arranged perpendicularly to the ideal optical axis and its center is located on the ideal optical axis, and the above-mentioned lens is arranged to receive the adjusted light beam that has passed through the convex lens. It is equipped with a photodetector placed on the ideal optical axis and a detector driving means for linearly driving the photodetector along the ideal optical axis, and when adjusting the angle, the detection surface of the photodetector is The drive is controlled so that it is located at the focal point of the convex lens, and when adjusting the position, the drive is controlled so that the detection surface of the photodetector is located at a predetermined distance from the focal point of the convex lens. It is.

Therefore, using one photodetector, it is possible to adjust the angle and position required for adjusting the optical axis R.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing the overall configuration of this embodiment. Note that the same parts as in FIG. 10 are given the same reference numerals, and detailed explanations will be omitted. In FIG. 1, reference numeral 22 denotes a detector driving device, which linearly drives and controls the photodetector 16 along the ideal optical axis in accordance with instructions from an automatic control section 23 consisting of a computer.

Here, the driving bag fi! 22, when the photodetector 16 is set at the position shown by the solid line in FIG. 1, the first total reflection mirror 13. The convex lens 15 and the photodetector 16 are arranged so as to satisfy the basic conditions for angular shift adjustment, and the driving device 2
2, when the photodetector 16 is set at the position shown by the dotted chain line in FIG. 1, the second total reflection mirror 12. The first total reflection mirror 13° convex lens 15 and the photodetector 16 are arranged so as to satisfy the basic conditions for adjusting the positional deviation.

The automatic control section 23 includes an arithmetic circuit, as shown in FIG.
A microprocessor 31 with a built-in memory, etc., an operation panel 32 equipped with operation switches for inputting a command to start optical axis adjustment, a display unit for outputting optical axis adjustment results, etc., and inputting a light detection signal from the photodetector 16. a signal input circuit 33,
A signal output circuit 34 that outputs a drive signal to the detector drive device 22, a signal output circuit 35 that outputs a drive signal to the drive device 20 of the first total reflection mirror 13, and a drive of the second total reflection mirror 12. It is comprised of a signal output circuit 36 that outputs a drive signal to the device 21.

The microprocessor 31 is program-controlled to operate as follows.

That is, it is activated by the optical axis adjustment start operation on the operation panel 32, and first, in order to adjust the angle deviation, a drive command is sent to the detector drive signal output circuit 34.
It22 and the detection surface of the photodetector 16 is connected to the convex lens 15.
the focal point f.

Next, the photodetector 16 is connected to the photodetector 16 via the photodetection signal input circuit 33.
The output of laser beam 1 is taken in, and from equations (1) and (2) above,
The angular deviation (θX, θy) of the optical axis of 1 is calculated, and based on this angular deviation (θX, θy), a drive command is sent to the mirror drive device i! via the first mirror drive signal output circuit 35. 20, and the first total reflection mirror 13 is (θx/2.θy/2)
Adjust the rotation only.

Thereafter, by repeating the rotational adjustment of the first mirror 13 in the same manner, the optical axis of the laser beam 11 is adjusted to be parallel to the ideal optical axis.

After the angle shift adjustment is completed, a drive command is given to the detector drive device 22 via the detector drive signal output circuit 34 in order to adjust the position shift, and the detection surface of the photodetector 16 is moved to the convex lens 15.
is located a predetermined distance d from the focal point f. Next, the output of the photodetector 16 is taken in through the photodetection signal input port '833, and the mirror rotation angle (θX) for adjusting the positional deviation of the optical axis of the laser beam 11 is determined from equations (7) and (8) above.

θy), and based on this rotation angle (θX, θy), the second mirror drive signal output circuit 36. A drive signal is applied to the mirror drive device 21 via the second total reflection mirror 1.
2 by (θx/2.θy/2), and then a drive signal is given to the mirror drive device 20 via the first mirror drive signal output circuit 35, and the first total reflection mirror 13 is rotated by (θx/2.θy/2).
Adjust the rotation by x72°θy/2). Thereafter, by repeating the rotational adjustment of the second mirror 12 and the first mirror 13 in the same manner, the laser beam 11 is adjusted so as to remain parallel to the ideal optical axis and eliminate positional deviation.

In this embodiment configured in this way, the laser beam 11 emitted from the laser oscillator 10 is totally reflected by the second total reflection mirror 12 and the first total reflection mirror 13, and is optically detected via the convex lens 15. 6. When the optical axis adjustment of the laser beam 11 is commanded in this state, first the detector driving bag f! 22 controls the drive of the photodetector 16 so that it is located at the focal point f of the convex lens 15. By doing this, the first mirror 13. The arrangement relationship between the convex lens 15 and the photodetector 16 satisfies the conditions necessary for adjusting the angle deviation, and the automatic control unit 23 rotationally adjusts the first mirror 13 based on the detection output of the photodetector 16. Accordingly, the angle shift adjustment of the laser beam 11 is performed.

Next, after the angular shift adjustment is completed, the photodetector 16 is driven and controlled by the detector driving device 22 so that it is positioned a predetermined distance d from the focal point f of the convex lens 15. By doing this, the second mirror 12. first mirror 1
3. The arrangement relationship between the convex lens 15 and the photodetector 16 satisfies the conditions necessary for positional shift adjustment, and the photodetector 1
Based on the detection output of 6, the automatic control unit 23 controls the second mirror 1
By adjusting the rotation g of the mirror 2 and the first mirror 13, the positional deviation of the laser beam 11 is adjusted.

As described above, according to the present embodiment, the detector drive device 22 that linearly drives the photodetector 16 along the ideal optical axis is provided, and the photodetector 16 is positioned at the focal position of the convex lens 15 when adjusting the angle deviation. When adjusting the positional deviation, the lens is positioned a predetermined distance d from the focal position of the convex lens 15, so that one photodetector 16 can perform the angular deviation adjustment and the positional deviation adjustment necessary for optical axis adjustment. Therefore, maintaining the accuracy of the photodetector is simplified, and the optical axis adjustment is not performed while the accuracy is unstable, so that the optical axis adjustment accuracy can be improved. Furthermore, since it is not necessary to divide the laser beam 11 into two perpendicular directions and the optical axis can be adjusted in only one direction, the system can be constructed in a narrow space and downsized.

In addition, although the optical axis adjustment of the laser beam 11 was shown in the said Example, it goes without saying that the light beam to be adjusted is not limited to a laser beam.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to perform the angular shift adjustment and position shift adjustment necessary for optical axis adjustment with one photodetector, and the accuracy of the photodetector can be improved. It is possible to provide an optical axis adjustment device that can be easily maintained, improve optical axis adjustment accuracy, and downsize the entire device.

[Brief explanation of drawings]

1 and 2 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a schematic diagram showing the overall configuration of the device, FIG. 2 is a block diagram of the automatic control section, and FIGS. FIG. 5 is a diagram explaining the principle of angular shift adjustment, FIGS. 6 to 9 are diagrams explaining the principle of position shift adjustment, and FIG. 10 is a schematic diagram showing the overall configuration of a conventional device. 10... Laser oscillator, 11... Laser light, 12.
...Second total reflection mirror 13...First total reflection mirror 15...Convex lens, 16...Photodetector, 22.
...detector drive device, 23... automatic control section. 3 1st r11

Claims (1)

[Claims] In an optical axis adjustment device that aligns the optical axis of a light beam to be adjusted with an ideal optical axis formed by arbitrary two points by arranging a plurality of mirrors and adjusting the rotation of the mirrors, a convex lens disposed vertically so that its center is located on the ideal optical axis; a photodetector disposed on the ideal optical axis to receive the adjusted light beam that has passed through the convex lens; and a detector driving means for linearly driving the photodetector along the ideal optical axis, and when performing angular shift adjustment, the drive is controlled so that the detection surface of the photodetector is located at the focal point of the convex lens. . An optical axis adjustment device, characterized in that when performing positional deviation adjustment, drive control is performed so that the detection surface of the photodetector is located at a position separated by a predetermined distance from the focal point of the convex lens.