JPH04318506A - Optical axis adjustment device - Google Patents

Abstract

PURPOSE:To provide the optical axis adjustment device which speedily adjust an optical axis, can align the optical axis with high resolution, and can increase the output of laser light and stably output it. CONSTITUTION:The optical axis adjustment device which adjusts the deviation of the optical axis of light outputted by a light source is equipped with a 1st reflecting mirror 12 which totally reflects or half-transmits and reflect the light from the light source, a slanting device 13 which receives an external operation control signal and slants the 1st reflecting mirror 12 in a desired direction, a polygonal conic mirror 14 which receives the light from the 1st reflecting mirror 12 nearby at the vertex of the conic body, plural photoelectric converters 15 which are arranged opposite the surfaces of the polygonal conic mirror 14 and convert reflected light from the mirror 14 into electric signals, and an operation control means 17 which controls the slanting device by outputting the operation control signal so as to hold the photodetection outputs from those photoelectric converters 14 in constant mutual relation.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a high-output laser device that sequentially multiplies and outputs laser light using laser oscillators arranged in multiple stages in series, and an optical axis adjustment device used in various optical measuring devices, optical surveying machines, etc. In particular, the present invention relates to an optical axis adjustment device that can freely adjust the optical axis of light.

0002

[Prior Art] Conventionally, a plurality of laser oscillators are connected in series in multiple stages, and a discharge circuit is provided for each laser oscillator.
There is a laser device that generates high-output laser light by sequentially driving each discharge circuit and amplifying laser light output from a first-stage laser oscillator step by step with each laser oscillator. In such a laser device, in order to increase the power of the laser light output from the final stage laser oscillator, it is necessary to arrange various optical components at appropriate positions and align the optical axes of the output light from each laser oscillator. There is.

The optical axis adjustment of the laser device as described above may be performed manually by a worker or automatically using a position detection element.

The former operation by a worker is a method in which a highly skilled worker uses past experience and intuition to align the optical axis while shifting the position of each optical component.

On the other hand, the latter type of automatic optical axis adjustment uses a semiconductor position detection device (hereinafter referred to as "PSD") 1 composed of a silicon photodiode or the like as shown in FIG. As shown, there is one using a four-division detection element 2.

PSD 1 has p-type silicon layer 4 formed on n-type substrate 3, and the positive polarity side of bias voltage 5 is n-type.
It is connected to the mold substrate 3 side, and the negative polarity side is the current detection element 6a,
This configuration is connected to electrodes 7a and 7b via 6b.

In such a PSD 1, when the spot light 8 is incident on the p-type silicon layer 4, the p-type silicon layer 4 and the n-type substrate 3 are short-circuited due to the photoelectric effect. At this time, assuming that the p-type silicon layer 4 has a uniform resistivity, the current I taken out from each electrode 7a, 7b
Since 1 and I2 are inversely proportional to the ratio of the distances X1 and X2 from the spot light incident point 9 to each electrode 7a and 7b, I1/
I2=X2/X1 (1) The incident position of the spot light 8 can be determined from the equation (1). Also, although FIG. 4 shows position detection only in the X-axis direction,
If electrodes are similarly provided in the axial direction, the two-dimensional position of the spot light 8 can be detected.

Further, the four-division detection element 2 shown in FIG.
It is composed of photodiodes 10a to 10d,
The position in the Y-axis direction can be determined by calculating the sum and difference of the currents output from each of the photodiodes 10a to 10d. Incidentally, the position in the X-axis direction is

0
009]

[Math 1]

The position in the Y-axis direction is proportional to the formula:

0
011]

[Math 2]

The position of the spot light 8 is determined by paying attention to the fact that it is proportional to .

[0013] Once the position of the spot light 8 has been determined using the position detection element as described above, the amount of deviation from the original position is calculated and the optical axis is controlled to make the amount of deviation zero. conduct.

[0014]

[Problems to be Solved by the Invention] However, when the optical axis is manually adjusted by an operator as described above, the alignment accuracy of the optical axis varies depending on the skill level of the adjustment operator, and the adjustment work requires a great deal of effort. It requires effort and time. Also,
After the optical axis is adjusted, the optical axis often shifts due to factors such as temperature and vibration, but it is necessary to readjust the optical axis manually at an appropriate time, which poses a problem in terms of responsiveness.

Furthermore, in the above-mentioned optical axis adjusting device, since there is a non-sensing portion between each photocathode of the four-part detection element, the beam diameter of the spot light 8 has to be increased, and the spectral sensitivity decreases accordingly. . Furthermore, if the electrical amplification factor is increased in order to eliminate the cause of this decrease in sensitivity, the accuracy of optical axis alignment cannot be increased because of the influence of disturbances (electrical noise, temperature, etc.). Furthermore, since a semiconductor element is used, the spectral sensitivity is largely dependent on temperature. Therefore, these position detection elements are not suitable for use in fine position adjustment such as laser optical axis adjustment.

The present invention has been made to solve the above problems, and it is possible to quickly and automatically adjust the optical axis, and to adjust the output light by adjusting the optical axis with sufficiently high resolution. An object of the present invention is to provide an optical axis adjustment device that can increase the amount of light and obtain stable output light.

[0017]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an optical axis adjusting device for adjusting the optical axis deviation of light output from a light source, in which the light from the light source is totally reflected or semi-transmitted. a first reflecting mirror that reflects light; a tilting device that receives an external operation control signal and tilts the first reflecting mirror in a desired direction; a second reflecting mirror that receives light near the apex; a plurality of photoelectric converters that are arranged facing each other on a plurality of surfaces of the second reflecting mirror and convert incident light from the second reflecting mirror into electrical signals; The present invention is configured to include an operation control means for controlling the tilting device by outputting the operation control signal so as to keep the mutual relationship between the light reception outputs of the respective photoelectric converters constant.

[0018]

[Operation] According to the present invention, in the initial adjusted state, the light from the first reflecting mirror is at the top of the second reflecting mirror, and the reflected light from there is divided into a number of angles. ,
Each split reflected light is detected by a photoelectric converter. The received light outputs of these photoelectric converters maintain the position of the tilting device in a balanced manner. When the light from the first reflecting mirror shifts, the light incident on a specific surface of the second reflecting mirror becomes stronger. As a result, the light receiving output of the photoelectric converter facing the surface increases. As the output balance of each photoelectric converter changes, an operation control signal is sent to the tilting device, and based on this operation control signal, the tilting device tilts the reflecting mirror in the direction of optical axis alignment, aligning the optical axis. .

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the apparatus of the present invention will be described below with reference to FIG.

This embodiment uses a laser oscillator and other light sources (
A first reflecting mirror 12 receives a spot light 11 incident from a source (not shown). The first reflecting mirror 12 is provided with tilting devices 13a and 13b for varying the tilt in the front, back, left, and right directions, that is, in any direction. As the tilting devices 13a and 13b, a device having an electric-displacement conversion function, such as a servo motor, a pulse motor, or an inch warmer, is used. A second reflective mirror (hereinafter referred to as a "polygonal pyramid mirror") 14 is arranged in the traveling direction of the light reflected by the first reflective mirror 12. This polygonal pyramidal mirror 14 is a polygonal pyramidal reflecting mirror composed of, for example, four mirrors 14a to 14d, and the first reflecting mirror 12
Spot light 11 from the mirror is reflected at different angles. Four mirrors 14a to 14 of the polygonal pyramid mirror 14
In each of the mirrors d, photoelectric converters 15a to 15d configured by a PSD or the like for converting light into an electric signal are arranged facing each other so as to receive reflected light from the corresponding mirror.

Note that each of the photoelectric converters 15a to 15d needs to have a size necessary to receive the reflected light from the required reflection portion of each of the mirrors 14a to 14d. 14a to 14d and photoelectric converter 15a
The light receiving area can be reduced by placing a condenser lens between 15d and 15d.

For example, the photoelectric converter 15c has a width that can maintain sufficient detection sensitivity when light corresponding to a space 16 (hatched area) formed by reflection from the mirror 14c enters, as shown in FIG. However, if a condensing lens is provided, the space portion 16 can be narrowed down to a necessary amount to make the area small, and the light receiving surface of the light receiving detector 15c can be made small.

Output signals from each of the photoelectric converters 15a to 15d are input to a control device 17. This control device 17 controls the tilting device 13 according to the received light output of the photoelectric converters 15a to 15d.
An operation control signal is supplied to a and 13b. For example, when the received light output from the photoelectric converter 15a increases, the tilting device 13a sends an operation control signal to tilt the reflecting mirror 12 so that the tilting device 13a rotates in the normal direction, that is, the spot light 11 goes toward the top side of the polygonal cone mirror 14. On the other hand, when the received light output from the photoelectric converter 16b increases, the tilting device 1
An operation control signal for tilting the reflecting mirror 12 in accordance with the reverse direction of the mirror 3a is supplied to the tilting device 13a.

Next, the operation of this embodiment configured as above will be explained.

In the initial adjusted state, the spot light 11 of the luminous flux reflected by the reflecting mirror 12 is irradiated onto the area indicated by the diagonal line S at the top of the polygonal pyramidal mirror 14, and each mirror 1
4a to 14d each receive a predetermined amount of light. A light reception output corresponding to the amount of light received by each of the mirrors 14a to 14d is output from the corresponding photoelectric converter 15, respectively. Control device 17
is calculated to control the tilting device 13 so as to maintain the relative relationship of the input signals from each of the photoelectric converters 15a to 15d, that is, to maintain this position (the position where the optical axis is adjusted).

When the spot light from the light source changes to a spot light 11'a as shown by the broken line in the figure for some reason, the reflected light 1 of the reflecting mirror 12 by this spot light 11'a
1'b is incident on the mirror 14c side of the polygonal pyramidal mirror 14 (
(S in the figure moves to S') and is reflected by this mirror 14c. At this time, the photoelectric converter 15c detects the spot light 11'c reflected from the mirror 14c, but this value increases compared to the amount of the spot light 11 before. Also, similarly 1
The amount of light of each of 4a, 14b, and 14d decreases or disappears. Therefore, the received light output from each of the photoelectric converters 15a to 15d changes from the previous value, and the control device 17
will be sent to.

After receiving such light reception output and performing arithmetic processing, the control device 17 outputs an operation control signal to rotate the tilting device 13b in the normal rotation direction, that is, the reflecting mirror 12.
Tilt it so that the side toward you as shown is lowered. As a result, the light trace S caused by the reflection spot 11'b from the reflection mirror 12
' part moves and enters the S part. In this case, the control is one-dimensional, but variable control can be achieved two-dimensionally if the tilting device 13 is, for example, a multi-jointed device equivalent to a robot.

As described above, according to this embodiment, the spot light 1
1 is applied to the vertex of the polygonal cone mirror 14 to magnify the optical axis deviation in each direction and enter the photoelectric converters 15a to 15d, and the control device 17 monitors the received light output of these photoelectric converters 15a to 15d. When the relative relationship between the received light outputs changes and an optical axis shift is detected, the reflecting mirror 12 is changed to a desired direction via the tilting device 13, and the reflected spot light 12 from the reflecting mirror 12 is moved to the first position. Unlike conventional manual work, this method eliminates the need for skilled workers, and also eliminates variations in optical axis alignment, allowing for quick adjustment of the optical axis even if optical axis misalignment occurs due to various factors. Axis alignment can be performed. In addition, the spot light 11 is transferred to a polygonal pyramidal mirror 14.
Since the output ratio of each detector is controlled to be constant, there is no dependence of temperature on spectral sensitivity as in the conventional case, and the cause of disturbance etc. is eliminated. can also be removed. The relationship between the light reception outputs of the respective detectors may be a sum, a difference, or a ratio, as long as it has the same form as the initial state. In addition, when the optical axis moves, the polygonal pyramidal mirror 14 is used to reflect the spot light 12 at a large angle, and the spot light 12 is incident on the photoelectric converters 15a to 15d with a large amplitude, so it can be controlled regardless of the signal level. The operation can be executed accurately, thereby obtaining an extremely large forward gain, and the optical axis deviation can be controlled more stably and precisely.

Note that in the above embodiment, the tilting device 1
Optical axis alignment was performed by tilting the reflecting mirror 12 in a desired direction using a polygonal pyramidal mirror 14.
Optical axes may be aligned by moving two-dimensionally in a plane. Furthermore, although a quadrangular pyramid-shaped reflection mirror is used as the polygonal pyramidal mirror 14, it may be a triangular pyramid-shaped reflection mirror or another polyhedral-shaped reflection mirror that can achieve the same effect.

Next, another embodiment of the present invention will be described with reference to FIG.

This embodiment shows optical axis adjustment when a combination of parallel and angular displacement of the light source occurs.

In this embodiment, a spot light 11 from a light source (not shown) is incident on a reflecting mirror 12. Reflection mirror 12
are horizontally adjustable mirror moving devices 21a, 21.
It has a built-in b. On the optical path of the reflected light from this reflecting mirror 12, a polygonal cone mirror 14 is arranged, as in the above embodiment. A photoelectric converter is disposed on each surface of this polygonal pyramid mirror 14, and the received light output is sent to a control device, and the mirror moving device 21 is controlled by an operation control signal from this control device.
a, 21b. In addition, on the optical path between the reflection mirror 12 and the polygonal pyramid mirror 14,
A semi-transparent mirror 22 is arranged. The angle of the semi-transparent mirror 22 can be adjusted by tilting devices 23a and 23b. Another polygonal cone mirror 24 is arranged on the optical path of the light reflected by the semi-transparent mirror 22. Around this polygonal pyramidal mirror 24, photoelectric converters are arranged corresponding to each surface, and the light reception outputs of these photoelectric converters are sent to a control device, and the tilting is performed according to the operation control signal of this control device. It is configured to control devices 23a, 23b.

Note that a semi-transparent mirror is omitted immediately in front of the polygonal pyramidal mirror 24.

In this embodiment configured as described above, when the light passing along the solid line causes a compound shift of parallel shift and angular shift as shown by the broken line (exaggerated in the figure), this shift is caused by a polygonal pyramid. The amount of deviation is detected by the mirror 14 and photoelectric converters around it, and horizontal adjustment is performed by mirror moving devices 21a and 21b. As a result, the reflecting mirror 12 moves to a position 12' indicated by a two-dot chain line in the figure. As a result, the incident spot light 11 is corrected to the position shown by the dashed line and enters the semi-transmissive mirror 22. Note that the distance between the polygonal pyramidal mirror 14 and the semi-transparent mirror 22 is ignored because it is shorter than the distance over which other light is refracted.

In this state, since the angle still remains, the optical axis of the light reflected by the semi-transmissive mirror 22 is shifted from the polygonal pyramidal mirror 24, as shown by the dashed line. This angular shift is detected using the spot light reflected by the semi-transmissive mirror 22 and incident on the other polygonal pyramidal mirror 24, and the tilting device 23a,
23b is controlled to adjust the angle θ. As a result,
The reflected light reflected by the semi-transparent mirror 22 is corrected to the original position of the solid line.

As described above, according to this embodiment, two sets of the optical axis adjustment devices shown in the above embodiment are combined, and optical axis deviations are compensated for each set in turn, so that parallel deviations and angular deviations are compensated for. Even if the optical axis is misaligned, it can be easily and accurately adjusted.

Note that if a transflective mirror is used instead of the polygonal pyramidal mirror 24 and a laser oscillator is arranged in the direction of the reflected light, a laser device having multiple stages in series can be realized.

[0038]

As described in detail above, according to the present invention, a spot light is applied to the vertex of the second reflecting mirror having a polygonal cone shape, the optical axis deviation of the light is magnified, and then the amount of deviation is measured by photoelectric conversion. Since the converter detects the deviation of the optical axis and tilts the total reflection or semi-transmission reflection mirror in the desired direction, the optical axis can be adjusted quickly and automatically. It is possible to provide an optical axis adjustment device that can perform optical axis alignment with high resolution and thus enables increased and stable output of laser light.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an optical axis adjustment device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the light receiving surface of a photoelectric converter and the size of a spot light.

FIG. 3 is a configuration diagram of an optical axis adjustment device according to another embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional optical axis adjustment device using a PSD.

FIG. 5 is a configuration diagram of a conventional optical axis adjustment device using a four-part detection element.

[Explanation of symbols]

12...Reflection mirror, 13...Tilt device, 14...Polygonal pyramid mirror, 15...Photoelectric converter, 17...Control device.

Claims (1)

[Claims] 1. An optical axis adjustment device for adjusting optical axis deviation of light output from a light source, comprising: a first reflecting mirror that totally or semi-transparently reflects the light from the light source; and an operation control signal from the outside. a tilting device that tilts the first reflective mirror in a desired direction in response to the received light; a second reflective mirror that is shaped like a polygonal pyramid and receives light from the first reflective mirror near the apex of the pyramid; A plurality of photoelectric converters are arranged facing each other on a plurality of surfaces of the second reflecting mirror and convert the reflected light from the second reflecting mirror into electrical signals, and the mutual relationship between the light receiving outputs of these photoelectric converters is constant. an optical axis adjustment device comprising: operation control means for controlling the tilting device by outputting the operation control signal so as to maintain the tilting device.