KR102319126B1 - Apparatus and method for generating and stabilizing of beam power - Google Patents

Abstract

Disclosed are a beam power generation and stabilization system and a method thereof. According to one embodiment of the present invention, the beam power generation and stabilization system includes a first beam generation part generating a first laser beam having a first quality and a beam stabilization part stabilizing power of the first laser beam. The beam stabilization part includes: a wavelength plate penetrated by the first laser beam; a motor housing the wavelength plate to normally or reversely rotate the same; a light sensing part sensing the first laser beam having penetrated the wavelength plate to generate light sensing information; and a control part controlling the motor using the light sensing information such that the first laser beam having penetrated the wavelength plate can have preset beam power. The control part outputs a positive current of fixed intensity or a negative current of fixed intensity, while controlling an application time for the positive current or the negative current in accordance with the light sensing information. Therefore, the present invention is capable of acquiring high control precision.

Description

Apparatus and method for generating and stabilizing beam power

The present invention relates to an apparatus and method for generating and stabilizing beam power, and more particularly, to an apparatus and method for generating and stabilizing a beam power for generating and stabilizing a laser beam with a predetermined power.

A laser experiment apparatus is a device for experimenting with various phenomena using a laser. Among them, the laser accelerator is a high-power microwave laser device for making an electron beam of a linear radiation accelerator.

Such a laser accelerator is applied as an important component in various industrial fields such as medical fields such as radiation therapy and diagnostic devices, polymer material development, power semiconductor manufacturing, and radiation processing fields such as sterilization.

As a prior art for such a laser beam, there are Korean Patent Laid-Open No. 10-1996-0009578 (Title of the Invention: Laser Beam Shutter Safety Control Method) and Japanese Patent Laid-Open No. 2009-283728 (Title of the Invention: Safety Device). .

However, these prior patents only suggest a shutter control method for safety of a space related to generation of a laser beam rather than generation of a laser beam, and the pulsed laser beam generated according to the prior art is sensitive to temperature, humidity, or air flow. Since it is difficult to drift for a long time and the fluctuation of a pulse peak to a peak is significant even for a short time, development for generating a higher quality laser beam is required.

SUMMARY OF THE INVENTION The present invention is to solve the problems of the prior art, and an object of the present invention is to provide an apparatus and method for generating and stabilizing beam power for generating high quality beam power and stabilizing the beam power to maintain a set standard. .

Another object of the present invention is to provide an apparatus and method for generating and stabilizing beam power in which the occurrence of malfunction is minimized and the precision is improved during feedback control of a motor that rotates a wave plate forward or reverse in relation to beam stabilization.

According to an aspect of the present invention, it includes a first beam generator for generating a first laser beam having a first property and a beam stabilizer for stabilizing the power of the first laser beam, wherein the beam stabilizer includes the first a wave plate through which the laser beam passes; a motor for receiving the wave plate and rotating it forward or reverse; A photo-sensing unit that detects the first laser beam passing through the wave plate to generate photo-sensing information, and the motor using the photo-sensing information so that the first laser beam passing through the wave plate has a preset beam power and a control unit for controlling the control unit, wherein the control unit outputs a positive current of a fixed intensity or a negative current of a fixed intensity, and generates beam power for adjusting an application time of the positive current or the negative current according to the light sensing information and a stabilization device.

In this case, when the power of the first laser beam is less than a preset beam power as a result of reading the photo-sensing information, the controller supplies the positive current to the motor to rotate the motor forward, and the controller provides a result of reading the photo-sensing information. When the power of the first laser beam is greater than a preset beam power, the negative current may be supplied to the motor to reverse rotation.

Also, the strength of the positive current and the strength of the negative current may be set to be the same.

Also, the motor may be a voice coil motor.

In addition, the photodetector may include a photodiode that converts the power change of the first laser beam into an optical signal and transmits it to the controller.

In addition, the beam power generation and stabilization device, further comprising an angular position sensor (Angular Position Sensor) for detecting the rotation angle of the motor, the control unit to the light detection information and the rotation angle detected by each position sensor Accordingly, the application time of the positive current or the negative current may be adjusted.

Also, the apparatus for generating and stabilizing beam power may further include a second beam generating unit that converts the first laser beam that has passed through the wave plate into a second laser beam having different properties.

According to another aspect of the present invention, a first beam generator includes generating a first laser beam having a first property and stabilizing the power of the first laser beam, wherein the stabilizing includes: a motor passing the first laser beam through a wave plate accommodated in the motor to rotate forward or reverse according to the rotation of generating photo-sensing information by a photo-sensing unit sensing the first laser beam passing through the wave plate; to control the motor, but in the step of controlling the motor, the control unit outputs a positive current of a fixed intensity or a negative current of a fixed intensity, but depending on the light sensing information, the positive current or the A method of generating and stabilizing beam power for controlling an application time of a negative current is provided.

In this case, in the step of controlling the motor, when the power of the first laser beam is smaller than a preset beam power as a result of reading the light sensing information, the controller supplies the positive current to the motor to rotate the motor forward, and the controller may supply the negative current to the motor to reverse rotation when the power of the first laser beam is greater than a preset beam power as a result of reading the light sensing information.

In addition, in the step of controlling the motor, the strength of the positive current and the strength of the negative current may be set to be the same.

In addition, the method of generating and stabilizing the beam power further comprises the step of each position sensor detecting a rotation angle of the motor, in the step of controlling the motor, the control unit is the light sensing information and each position sensor The application time of the positive current or the negative current may be adjusted according to the sensed rotation angle.

According to an embodiment of the present invention, the beam power is stabilized through a wave plate that is accommodated in the motor and rotates forward or backward, and the feedback control of the motor fixes the strength of the current and adjusts the direction and application time of the current As a result, it is possible to minimize the malfunction of the motor and obtain high control precision.

1 is a block diagram of an apparatus for generating and stabilizing beam power according to an embodiment of the present invention.
2 is a diagram illustrating a feedback control method of a motor in the apparatus for generating and stabilizing beam power according to an embodiment of the present invention.
3 is a flowchart of a method for generating and stabilizing beam power according to an embodiment of the present invention.
4 is a detailed flowchart of a step of stabilizing the power of a first laser beam in the method for generating and stabilizing beam power according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention, parts irrelevant to the description are omitted from the drawings, and the same reference numerals are assigned to the same or similar components throughout the specification.

In the present specification, terms such as "comprise" or "have" are intended to describe the existence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but one or more other features It should be understood that this does not preclude the possibility of addition or existence of numbers, steps, operations, components, parts, or combinations thereof.

1 is a block diagram of an apparatus for generating and stabilizing beam power according to an embodiment of the present invention.

The apparatus for generating and stabilizing beam power according to an embodiment of the present invention generates a laser beam and stabilizes the generated laser beam to have a set power. An embodiment of the present invention may be applied to a laser accelerator or the like.

The apparatus for generating and stabilizing beam power according to an embodiment of the present invention may generate and stabilize a laser beam having a first property and then convert it into a laser beam having a second property.

Referring to FIG. 1 , the apparatus for generating and stabilizing beam power according to an embodiment of the present invention may include a first beam generator 10 , a beam stabilizer 20 , and a second beam generator 30 . have.

The first beam generator 10 generates a first laser beam having a first property. The first beam generator 10 may be a seed beam oscillator for generating a high-power laser beam. For example, the first beam generator 10 may include a laser oscillator.

In an embodiment of the present invention, the first property of the first laser beam may be an infrared (IR) laser beam of 760 nm and 120 Hz. Of course, this is an example, and the first property may vary depending on the required output of the laser beam.

In addition, the first beam generator 10 may include a configuration for adjusting the pulse width and intensity of the generated first laser beam. For example, the first beam generator 10 may include a regenerative amplifier.

The beam stabilizer 20 stabilizes the power of the first laser beam. The beam stabilizer 20 may stabilize the wavelength and/or power of the first laser beam generated by the first beam generator 10 .

In one embodiment of the present invention, the beam stabilizing unit 20 includes a wave plate 21 , a motor 22 , a beam distribution unit 23 , a light sensing unit 24 , a control unit 25 , and each position sensor 26 . ) may be included.

The wave plate 21 is arranged to allow the first laser beam to pass therethrough. That is, the wave plate 21 is disposed on the movement path of the first laser beam generated by the first beam generator 10 . For example, the wave plate 21 may be formed of a half wave plate.

In one embodiment of the present invention, the power (intensity) of the first laser beam can be adjusted using linear polarization. In other words, the wavelength and/or power of the first laser beam passing through the wave plate 21 may be finely adjusted according to the rotation angle of the wave plate 21 .

The motor 22 receives the wave plate 21 and rotates it forward or reverse. Incidentally, when the motor 22 rotates forward, the wave plate 21 rotates forward, and when the motor 22 rotates reversely, the wave plate 21 rotates reversely.

As described above, the wavelength and/or power of the first laser beam passing through the wave plate 21 may be adjusted according to the rotation angle of the wave plate 21 . Accordingly, in one embodiment of the present invention, the wavelength and/or power of the first laser beam may be adjusted by rotating the wave plate 21 forward or reverse according to the rotation of the motor 22 . As described above, the motor 22 is coupled to the wave plate 21 to rotate the wave plate 21 forward or backward, and may function as a variable retarder that adjusts the intensity of a beam with polarized light.

In one embodiment of the present invention, the motor 22 may be a motor operated by receiving DC power. At this time, the motor 22 may rotate forward when a positive current is applied, and reverse when a negative current is applied. For example, the motor 22 may be a voice coil motor.

The beam distribution unit 23 is disposed between the combination of the wave plate 21 and the motor 22 and the second beam generating unit 30 to transmit the first laser beam passing through the wave plate 21 to the light sensing unit 24 . ) or sent to the second beam generator 30 . The beam splitter 23 may be formed of a general light splitter.

The photodetector 24 detects the first laser beam passing through the wave plate 21 to generate photodetection information. The photodetector 24 may convert a minute change in beam power into an optical signal in real time and transmit it to the controller 25 . In an embodiment of the present invention, the photodetector 24 may be formed of a photodiode that converts a change in power of the first laser beam into an optical signal and transmits it to the controller 25 .

The controller 25 controls the motor 22 using the light sensing information so that the first laser beam passing through the wave plate 21 has a preset beam power. The control unit 25 reads the light sensing information to determine whether the first laser beam has a preset beam power, and outputs a positive current of a fixed intensity or a negative current of a fixed intensity according to the reading result to the motor 22 However, it is possible to adjust the application time of the positive current or the negative current, that is, the pulse width according to the light sensing information.

Referring to FIG. 2 , in an embodiment of the present invention, when the power of the first laser beam is less than a preset beam power as a result of reading the light sensing information, the controller 25 supplies a positive current to the motor 22 to When the power of the first laser beam is greater than a preset beam power as a result of reading the light sensing information, a negative current may be supplied to the motor 22 to reverse rotation. In this case, the strength of the positive current and the strength of the negative current may be set to be the same.

In an embodiment of the present invention, the control unit 25 constantly fixes the strength of the positive current and the negative current, and the degree (rotation angle) of the forward or reverse rotation of the motor 22 is positive current or negative current having a constant strength. It is controlled through the application time (pulse width) of the negative current.

For example, the control unit 25 outputs a positive current of the same intensity when the motor 22 is rotated forward at a first angle and at a second angle greater than the first angle, but in the latter case, the current is compared to the former. The pulse width (current application time) of is larger. In addition, when the motor 22 is reversely rotated by a first angle and a second angle greater than the first angle, the control unit 25 outputs a negative current of the same intensity, but in the latter case, the pulse of the current compared to the former It is possible to take a larger width (current application time).

As described above, the control unit 25 outputs a current of a certain intensity, but adjusts the degree of rotation of the motor 22 through a change in the application time (pulse width). In one embodiment of the present invention, such a control method of the controller 25 may be defined as a current intensity fixed PWM (Pulse Width Modulation) method.

In the general PWM method, the number of revolutions of the motor is changed like the analog method by adjusting the duty cycle of the driving voltage of the motor. Alternatively, the inverter function is implemented by adjusting the duty cycle of the driving voltage of the motor.

However, in the embodiment of the present invention, the current intensity fixed PWM (Pulse Width Modulation) method adopted by the control unit 25 is a method of feeding back the beam power in real time for every pulse, not pulse width modulation for driving a general inverter or analog motor. (shot to shot), in the case of a high frequency (high frequency), by selecting f/n, there is a big difference from the conventional PWM method in that the beam power can be compensated for with a fast cycle.

According to an embodiment of the present invention, since the control method of the control unit 25 modulates the pulse width but maintains the pulse strength constant, the control program built into the control unit 25 controls the intermediate value ( (corresponding to the beam power set value) to virtual 0 (zero), set the top to the positive (+) direction and the bottom to the negative (-) direction, and then modulate the pulse width to adjust the rotation angle of the wave plate 21 can

Accordingly, when the beam shakes in order to maintain the power of the first laser beam at a preset beam power set value (a user's required value), the control unit 25 turns the wave plate 21 coupled to the motor 22 positive/negatively. By rotating in the direction, the beam power is increased (+) or small (-) and feedback control is performed.

Meanwhile, the control unit 25 may utilize the rotation angle of the motor 22 detected by each position sensor 26 as input information in addition to the light sensing information of the light sensing unit 24 . That is, in one embodiment of the present invention, the control unit 25 can adjust the application time (pulse width) of the positive or negative current of a certain intensity according to the light detection information and the rotation angle sensed by each position sensor 26 . have.

In an embodiment of the present invention, the control unit 25 may include an input/output device (I/O device), a control PC (Control PC), a current amplifier (Current Amplifier), and a DC power supply (DC Power Supply). have.

The input/output device may receive light sensing information. In this case, the light sensing information may be an analog signal, and the input/output device converts it and transmits it to the control PC. In addition, the control PC may receive the rotation angle from each position sensor (Angular Position Sensor, 26) in addition to the light sensing information and perform the feedback control of the current intensity fixed PWM method as described above through the built-in control program. In this case, the rotation angle may be transmitted as a digital signal.

The signal output as a result of feedback control from the control PC is transmitted to the input/output device as a digital signal, and the input/output device converts it into an analog signal and transmits it to the current amplifier. The current amplifier may receive a signal transmitted from the input/output device as an input, receive a pulse corresponding to the signal from the DC power supply, and output it to the motor 22 .

Each position sensor 26 senses the rotation angle of the motor 22 and transmits the sensed rotation angle to the controller 25 . As described above, the controller 25 may adjust the application time of the positive current or the negative current according to the light sensing information and the rotation angle sensed by each position sensor 26 .

The second beam generating unit 30 converts the first laser beam passing through the wave plate 21 of the beam stabilizing unit 20 into a second laser beam having different properties. For example, another property of the second laser beam may be an ultraviolet (UV) laser beam of 266 nm and 120 Hz. The second laser beam converted by the second beam generator 30 to have the second property may be supplied in the form of an electron gun (not shown).

3 is a flowchart of a method for generating and stabilizing beam power according to an embodiment of the present invention.

Referring to FIG. 3 , the method for generating and stabilizing beam power according to an embodiment of the present invention includes generating a first laser beam having a first property ( S10 ), and stabilizing the power of the first laser beam ( S20 ). ) and generating a second laser beam (S30).

The step of generating the first laser beam ( S10 ) may be performed by the first beam generating unit 10 , and the step of stabilizing the power of the first laser beam ( S20 ) is performed by the beam stabilizing unit 20 . can be Also, the step of generating the second laser beam ( S30 ) may be performed by the second beam generating unit 30 .

4 is a detailed flowchart of a step of stabilizing the power of a first laser beam in the method for generating and stabilizing beam power according to an embodiment of the present invention.

Referring to FIG. 4 , stabilizing the first laser beam includes passing the first laser beam through the wave plate 21 accommodated in the motor 22 so as to rotate forward or reverse according to the rotation of the motor 22 . (S21), the photodetector 24 detects the first laser beam passing through the wave plate 21 to generate photodetection information (S22), each position sensor 26 rotates the motor 22 Sensing the angle (S23) and the control unit 25 controlling the motor 22 using the light sensing information so that the first laser beam passing through the wave plate 21 has a preset beam power (S24) ) is included.

In an embodiment of the present invention, the step of generating the light sensing information (S22) and the step of detecting the rotation angle of the motor 22 (S23) may proceed simultaneously or the order may be changed.

In the step (S24) of controlling the motor, the controller 25 outputs a positive current of a fixed intensity or a negative current of a fixed intensity, and adjusts the application time of the positive current or the negative current according to the light sensing information. In more detail, when the power of the first laser beam is less than a preset beam power as a result of reading the light sensing information, the control unit 25 supplies a positive current to the motor 22 to rotate it forward, and reads the light sensing information. As a result, when the power of the first laser beam is greater than the preset beam power, a negative current may be supplied to the motor 22 to reverse rotation. In this case, the strength of the positive current and the strength of the negative current may be set to be the same.

In addition, in the step of controlling the motor, the controller 25 may adjust the application time of the positive current or the negative current by using both the light sensing information and the rotation angle sensed by each position sensor 26 .

Further detailed descriptions related to the method for generating and stabilizing beam power according to an embodiment of the present invention are the same as those described with respect to the apparatus for generating and stabilizing beam power according to an embodiment of the present invention, and thus will be omitted to avoid overlap.

As described above, according to the present invention, since the current control method is used instead of the voltage, the rotation angle of the motor capable of controlling the current can be controlled in a proportional manner between the pulse width and the rotation angle. Accordingly, even when a relatively low-cost voice coil motor is applied, the rotation control of the wave plate can be precisely performed, and the beam power can be more effectively stabilized.

Although one embodiment of the present invention has been described, the spirit of the present invention is not limited by the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention can add components, within the scope of the same spirit, Other embodiments may be easily proposed by changes, deletions, additions, etc., but these will also fall within the scope of the present invention.

10: first beam generating unit 20: beam stabilizing unit
30: second beam generator

Claims (11)

a first beam generator for generating a first laser beam having a first property; and
and a beam stabilizing unit for stabilizing the power of the first laser beam,
The beam stabilization unit,
a wave plate through which the first laser beam passes;
a motor for receiving the wave plate and rotating it forward or reverse;
a photo-sensing unit that detects the first laser beam passing through the wave plate and generates photo-sensing information; and
and a control unit for controlling the motor using the light sensing information so that the first laser beam passing through the wave plate has a preset beam power,
The control unit outputs a positive current of a fixed intensity or a negative current of a fixed intensity, and adjusts an application time of the positive current or the negative current according to the light sensing information,
When the power of the first laser beam is less than a preset beam power as a result of reading the optical sensing information, the control unit supplies the positive current to the motor to rotate the motor forward, and the control unit provides the first laser beam as a result of reading the optical sensing information. 1 When the power of the laser beam is greater than the preset beam power, the negative current is supplied to the motor to reverse rotation,
A beam power generating and stabilizing apparatus in which the intensity of the positive current and the intensity of the negative current are set to be the same. delete delete The method of claim 1,
The motor is a voice coil motor (Voice Coil Motor) beam power generation and stabilization device. The method of claim 1,
The photodetector includes a photodiode that converts the power change of the first laser beam into an optical signal and transmits it to the controller. The method of claim 1,
Further comprising an angular position sensor (Angular Position Sensor) for detecting the rotation angle of the motor,
The control unit is a beam power generation and stabilization apparatus for adjusting the application time of the positive current or the negative current according to the light detection information and the rotation angle sensed by each position sensor. The method of claim 1,
and a second beam generator configured to convert the first laser beam passing through the wave plate into a second laser beam having different properties. generating, by a first beam generator, a first laser beam having a first property; and
stabilizing the power of the first laser beam;
The stabilizing step is
passing the first laser beam through a wave plate accommodated in the motor to rotate forward or reverse according to the rotation of the motor;
generating photo-sensing information by a photo-sensing unit detecting the first laser beam passing through the wave plate; and
A control unit controlling the motor using the light sensing information so that the first laser beam that has passed through the wave plate has a preset beam power,
In the step of controlling the motor, the control unit outputs a positive current of a fixed intensity or a negative current of a fixed intensity, and adjusts an application time of the positive current or the negative current according to the light sensing information,
In the step of controlling the motor, when the power of the first laser beam is less than a preset beam power as a result of reading the light sensing information, the controller supplies the positive current to the motor to rotate the motor forward, and the controller As a result of reading the light sensing information, when the power of the first laser beam is greater than a preset beam power, the negative current is supplied to the motor to reverse rotation,
In the controlling of the motor, the intensity of the positive current and the intensity of the negative current are set to be the same. delete delete 9. The method of claim 8,
Each position sensor further comprises the step of detecting the rotation angle of the motor,
In the step of controlling the motor, the control unit is a beam power generation and stabilization method for adjusting the application time of the positive current or the negative current according to the light detection information and the rotation angle sensed by each position sensor.

Images