JP2002048510A - Method and device for detecting position and intensity of laser beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a position and intensity of a laser beam by an inexpensive device. SOLUTION: A matal thin film 2 is provided on a surface of a quartz oscillator 1 to be connected to a quartz oscillator signal input part 6 through a lead wire 3, the thin film 2 of the quartz oscillator 1 is irradiated with the laser beam emitted from a laser beam emitting means 5, and a signal thereof is input into the signal input part 6. A resonance frequency out of the signal is measured in a resonance frequency measuring part 7. Since the resonance frequency is brought into prescribed correlation to a position from the center of the laser beam emitted toward the quartz oscillator, the laser beam emitting position is measured in a laser beam emitting position measuring part 9 based on the correlation. An output of the input signal is measured in an output measuring part 8. Since the output has prescribed correlation to the resonance frequency of the quartz oscillator, an actual emission intensity of the laser beam 4 is measured in a laser beam emission intensity measuring part 10, based on the resonance frequency in the resonance frequency measuring part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting the position and intensity of a laser beam, which are arranged in a laser beam path and determine the position and intensity of laser beam irradiation on a mirror on which a metal thin film is deposited. More particularly, the present invention relates to a method and apparatus for detecting the position and intensity of laser light using the fact that the frequency change of a quartz oscillator depends on the irradiation position and intensity of laser light.

[0002]

2. Description of the Related Art In recent years, laser light has been actively used for various researches and developments, and has been used for various measurements in industry. In order to use laser light, it is necessary to determine the irradiation position of the laser light in the laser light path,
Often, light intensity must also be detected.

A general method of detecting the position of a laser beam includes a simple method of printing a pattern of the laser beam on a thermal paper or an acrylic plate to visualize the position, and inserting a linear array or a four-quadrant detector into the laser beam path. And a method of quantitatively measuring it.

[0004]

However, it is impossible to accurately detect the position and intensity of the laser beam by a simple method using thermal paper or an acrylic plate, and the optical system is temporarily shut off. There is a need to. In the method using a linear array or a four-quadrant detector, although the position and intensity of the optical system can be measured accurately, it is necessary to introduce a dedicated branch in the laser optical path. There is a problem that control and analysis of the data is required.

[0005] Under such circumstances, the present invention utilizes the fact that the crystal oscillator depends on the laser beam irradiation position and the laser beam energy to determine the laser beam irradiation position in the laser beam path. It is an object of the present invention to provide a method for detecting light and light intensity, and an apparatus for performing the method.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to utilize a quartz oscillator for determining the irradiation position and intensity of a laser beam, and as a result, have completed the present invention. The invention according to claim 1 irradiates the surface of the crystal unit with laser light to measure the resonance frequency of the crystal unit, and obtains the relationship between the irradiation position of the laser light and the resonance frequency obtained in advance, The present invention provides a method for detecting a laser beam irradiation position, which comprises measuring a laser beam irradiation position.

According to a second aspect of the present invention, the surface of the quartz oscillator is irradiated with a laser beam to measure the resonance frequency of the quartz oscillator and the output of the laser beam, and the output is changed according to the previously obtained irradiation position. According to the present invention, there is provided a method for detecting the intensity of a laser beam, which comprises measuring the irradiation intensity of a laser beam based on data on a relationship between a resonance frequency and an output.

According to a third aspect of the present invention, there is provided means for measuring a resonance frequency of a quartz oscillator irradiated with a laser beam, and the measurement using data of a relationship between an irradiation position of the laser beam and a resonance frequency obtained in advance. And a means for measuring an irradiation position of the laser light corresponding to the determined resonance frequency.

According to a fourth aspect of the present invention, there is provided a means for measuring a resonance frequency and an output of a quartz oscillator irradiated with a laser beam, and a relation between a resonance frequency and an output which are obtained in advance and vary with the irradiation position. And a means for measuring the irradiation intensity of the laser beam based on the data.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a block diagram schematically showing an embodiment of an apparatus for implementing a method for detecting the position and intensity of a laser beam according to the present invention, in which various functions are shown in a block diagram. A state is shown in which the vibrator 1 is irradiated with the laser light 4 from the laser light irradiation means 5 and the metal thin film portion of the quartz vibrator 1 is irradiated.

This crystal resonator may be a known one,
It is preferable that a metal substrate, particularly, a deposited thin film of gold, silver, platinum, aluminum or the like be formed on both surfaces of the quartz substrate. This metal deposited thin film is formed as a metal thin film 2 at the center of a circular quartz oscillator 1 as shown in the front view of FIG.
The metal thin film portion is extended and connected to the lead wire 3, and the lead wire 3 is led out from the front and back of the crystal unit 1.

There is no particular limitation on the wavelength and intensity of the laser beam applied to the crystal unit 1, for example, a wavelength of 100-1000 nm and an output of 0.1 mW-1 kW.
Grades can be used.

As shown in FIG. 1, when a metal thin film 2 of a quartz oscillator 1 is irradiated with a laser beam 4 from a laser beam irradiating means 5, its output signal is transmitted through a lead wire 5 to a quartz oscillator signal. It is input to the input unit 6. Based on the signal, the resonance frequency measurement unit 7 measures the resonance frequency of the quartz oscillator that changes with the laser light 4 irradiated from the laser light irradiation unit. The data obtained here is, for example, FIG.
This data is obtained in advance. Based on this graph, for example, the metal thin film 2 is formed in a range of 1 mm to 5 mm from the center, and the irradiation position L (mm) is obtained by measuring the resonance frequency of the quartz resonator when irradiating the laser light therewith. be able to.

In the output intensity measuring section 8, output value data relating to the irradiation intensity of the laser beam input to the crystal oscillator signal input section 6 and the crystal value relating to the position of the laser beam incident on the crystal oscillator are provided. The actual intensity of the emitted laser light can be calculated from the resonance frequency data of the vibrator.

That is, as shown in FIG. 4, the resonance frequency and the output (Power) of the laser beam applied to a specific portion of the crystal unit are substantially proportional to each other. Once the relevant resonance frequency is obtained,
The output ratio (%) is obtained based on the value, and the irradiation intensity of the actually irradiated laser light can be obtained from the value and the output value data from the crystal oscillator.

[0016]

According to the method for detecting the position and intensity of laser light using a quartz oscillator according to the present invention, the position and intensity of laser light can be measured using a single inexpensive quartz oscillator, and optical measurement can be performed. It is extremely useful as a device for use.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an apparatus for detecting an irradiation position and intensity of a laser beam according to the present invention.

FIG. 2 is a front view of a crystal unit used in the apparatus.

FIG. 3 is a graph showing a relationship between a resonance frequency measured by the apparatus and an irradiation position of laser light.

FIG. 4 is a graph showing a relationship between a resonance frequency and an output measured by the device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz crystal oscillator 2 Metal thin film 3 Lead wire 4 Laser light 5 Laser light irradiation means 6 Crystal oscillator signal input part 7 Resonance frequency measurement part 8 Output intensity measurement part 9 Laser light irradiation position measurement part 10 Laser light irradiation intensity measurement part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoru Shimada 1-1-1, Higashi, Tsukuba, Ibaraki Pref., National Institute of Advanced Industrial Science and Technology (72) Inventor Takashi Fukuda 1-1-1, Higashi, Tsukuba, Ibaraki, Japan Within the Institute of Engineering, Industrial Technology (72) Inventor Hiroo Matsuda 1-1-1, Higashi, Tsukuba, Ibaraki Pref. Within the Technical Research Institute (72) Inventor Agus Hariyono 1-1-1 Higashi, Tsukuba, Ibaraki Pref. AB09 BA40 DA05 5F072 HH02 JJ08 KK30

Claims (4)

[Claims] 1. A method for measuring the resonance frequency of a quartz oscillator by irradiating a laser beam onto the surface of the quartz oscillator, and obtaining data on the relationship between the irradiation position of the laser beam and the resonance frequency obtained in advance.
A method for detecting a laser beam irradiation position, comprising measuring a laser beam irradiation position. 2. A method of irradiating a laser beam onto a surface of a quartz oscillator to measure a resonance frequency of the quartz oscillator and an output of the laser beam, and obtaining data on a relationship between the resonance frequency and the output, which is previously obtained and changes depending on the irradiation position. A method for detecting the intensity of a laser beam, comprising: measuring an irradiation intensity of the laser beam. 3. A means for measuring a resonance frequency of a quartz oscillator irradiated with laser light, and a laser corresponding to the measured resonance frequency based on data on a relationship between an irradiation position of laser light and a resonance frequency obtained in advance. A device for detecting a laser light irradiation position, comprising: means for measuring a light irradiation position. 4. An irradiation intensity of a laser beam based on a means for measuring a resonance frequency and an output of a quartz oscillator irradiated with a laser beam, and data on a relationship between the resonance frequency and an output which change in accordance with the irradiation position obtained in advance. And a means for measuring the intensity of the laser beam.