Optics: measuring and testing – By polarized light examination – With light attenuation
Patent
1981-09-09
1984-10-02
Punter, William H.
Optics: measuring and testing
By polarized light examination
With light attenuation
324 65P, 324149, 356 73, 356121, 356215, 356222, G01B 1114, G01J 100, G01J 144, G01R 1073
Patent
active
044744684
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of and apparatus for measuring a laser beam and, more particularly, to a laser beam measuring method and apparatus in which an object having a resistance that is variable in response to temperature is disposed in the laser beam of high level of energy and the power and position of the laser beam are measured through the measurement of the resistance of the object.
BACKGROUND ART
In effecting a processing such as welding, cutting, surface treatment or the like by a laser processing device, the laser beam is emitted from a laser oscillator and the path of beam is changed by a reflective mirror, while focusing the beam by a lens on the work to be processed. The power of the laser beam emitted from the oscillator affects the workability of the work. It is, therefore, necessary to measure the power of the laser beam. One of the known methods of measuring the power is to use a detachable full-reflecting mirror, a "shutter", in the path of the laser beam and to measure the laser beam reflected by this mirror using a power meter. This method, however, cannot be used without interrupting the processing, because the beam path is intercepted during the measurement of the power.
Japanese Patent Laid-open No. 99792/1978 shows, particularly at FIG. 1 attached thereto, a method of continuously monitoring the power of the laser beam. This method makes use of a half-transmissive mirror adapted to reflect a part of the laser beam and the reflected beam is monitored. This method is also unsatisfactory in that the power of the laser beam is lost undesirably by the half-transmissive mirror disposed in the path of laser beam.
Furthermore, this type of laser beam device involves a problem that the path of the laser beam to be directed to the work is undersirably deviated due to slight inclination or offset of the mirrors incorporated in the optical system, attributable to a temperature change. This problem is serious particularly in the laser device for production purposes, because the laser source in such device is usually located at a distance from the work to inconveniently amplify the offset of the beam path. Namely, even a small deviation at the laser source causes an unacceptably large offset at the position of the work. This offset of the beam path causes not only the position of application of the beam onto the work, but also a deviation of a part of the laser beam from the effective plane of the optical system resulting in a scattering of the laser beam, i.e. a lowered efficiency of use of the laser power, to deteriorate the processing performance of the laser power.
DISCLOSURE OF THE INVENTION
Accordingly, an object of the invention is to provide a method of and apparatus for continuously measuring or detecting the power or position of the laser beam without interrupting the latter.
Another object of the invention is to provide a method of and apparatus for measuring a laser beam that is capable of measuring or detecting the power or position of the laser beam at an extremely reduced level of power loss of the laser beam.
To these ends, according to the invention, the power of the laser beam or the position of the beam path are detected through measurement or detection of a change in the resistance in an elongated object disposed in the laser beam.
The position of the laser beam can be detected by, for example, causing a relative motion between the laser beam and the object disposed in the laser beam. Namely, the distribution of the resistance change corresponding to the distribution of intensity of the laser beam is known as a result of this relative motion. Also, the laser beam power is known from the distribution by, for example, integrating the distribution of laser beam.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of a laser processing device incorporating a laser beam measuring apparatus constructed in accordance with an embodiment of the invention;
FIG. 2 is a sectional view of a laser beam measuring apparatus shown in F
REFERENCES:
patent: 1229740 (1917-06-01), Furstenau
patent: 2427094 (1947-09-01), Evans
patent: 2633525 (1953-03-01), Wells
patent: 3118062 (1964-01-01), Ilgenfritz et al.
patent: 3182262 (1965-05-01), Schumann
patent: 3649840 (1972-03-01), Thorn et al.
patent: 3694746 (1972-09-01), Hopfer
patent: 3878500 (1975-04-01), Svechnikov et al.
Morrison, S. R. "A New Type of Photosensitive Junction Device" Solid State Electronics, Pergamon Press, 1963, pp. 485-494.
Hofper, S. "The Design of Broad-Band Resistive Radiation Probes" IEEE Trans on Instru. & Measurement, 11-1972, pp. 416-421.
Wacker et al. "Quantifying Hazardous Electromagnetic Fields: Scientific Basis & Practical Considerations" IEEE Trans. on Microwave Theory & Tech. 7-1971, pp. 178-187.
Bassen et al. "Em Probe with Fiber Optic Telemetry System" Microwave Jr. 4-1977, pp. 35, 38-39.
Siekman et al. "A Simple Power-Output Meter Specially Designed for Continuous Laser Beams" Philips Res. Repts 23, 1968, pp. 375-387.
Quinn, A. A., "A Rapid Inexpensive Method for Determining the Spatial Intensity Distribution of a Laser Beam", Review of Sci. Instrm. 1971, pp. 981-982.
Blum et al., "Beam Position & Intensity Analyzing Device", IBM Tech. Disc. Bull., 3-1970, pp. 1594-1595.
Kuwabara Kouji
Sasaki Kouji
Shirakura Toshiharu
Sugawara Hiroyuki
Takemori Satoshi
Hitachi , Ltd.
Punter William H.
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