Temperature measuring apparatus utilizing radiation

• US 5,235,399 A
• Filed: 06/24/1991
• Issued: 08/10/1993
• Est. Priority Date: 09/06/1990
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Usui, Tatehito, Watanabe, Tomoji, Ooshima, Takehiko, Kobayashi, Junichi, Sasabe, Shunji
• Primary Examiner(s): McGraw, Vincent P.
• Assistant Examiner(s): KEESEE, LACHARLES
• Application Number:
  US07/719,945
• Time in Patent Office: 778 Days
• Field of Search: 356/43, 356/44, 356/45, 356/46, 356/48, 356/49, 356/50, 356/51, 356/418, 356/314, 250/214, 250/227.11, 374/121, 374/130, 374/131, 118/712, 118/666, 118/715, 118/723, 427/10, 204/298.01, 204/298.07, 204/298.09, 204/298.32
• US Class Current: 356/45
• CPC Class Codes: G01J 5/0014 for sensing the radiation from gases, flames
• CPC Class Codes: G01J 5/0018 Flames, plasma or welding
• CPC Class Codes: G01J 5/06 Arrangements for eliminating effects of disturbing radiation; Arrangements for compensating changes in sensitivity for adjusting of solid angle of collected radiation G01J5/07; means for wavelength selection G01J5/0801
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors
• CPC Class Codes: G01J 5/59 using polarisation; Details thereof
• CPC Class Codes: G01J 5/602 using selective, monochromatic or bandpass filtering

Abstract

An apparatus for measuring the temperature of an object placed in a plasma by utilizing radiation includes measuring means for measuring the intensity of radiation from the object and the intensity of plasma light in different directions at the same time. The measuring means includes a first lens for receiving the radiation from the object and the plasma light, a second lens for converting the output beam of the first lens into parallel light rays, a third lens for focusing the parallel light rays, and an interference filter disposed rotatably between the second lens and the third lens.

Claims

1. A temperature measuring apparatus utilizing radiation, comprising:

measuring means for measuring an intensity of radiation from a to-be-measured object placed in a plasma and an intensity of a plasma light, in different directions at the same time;

means for correcting a measured value of the intensity of the radiation by the measured value of the intensity of the plasma light to determine a correct intensity of thermal radiation of the to-be-measured object on the basis of the measured values being obtained by the measuring means; and

means for calculating the temperature of the to-be-measured object from the correct intensity of thermal radiation thus obtained.

2. A temperature measuring apparatus utilizing radiation as claimed in claim 1, wherein the measuring means includes:

a multi-surface mirror for receiving radiation from the to-be-measured object placed in the plasma and the plasma light, in different directions at the same time, to reflect the radiation and the plasma light in the same direction;

a camera lens for receiving light reflected from the multi-surface mirror;

a first relay lens for converting the output beam of the camera lens into parallel light rays;

an interference filter for transmitting a specified wavelength component of the parallel light rays;

a second relay lens for focusing a light beam having passed through the interference filter; and

an imaging element for converting an image formed of the focused beam into a video signal.

3. A temperature measuring apparatus utilizing radiation, comprising:

a multi-surface mirror for receiving radiation from a to-be-measured object placed in a plasma and plasma light, in different directions at the same time, to reflect the radiation and the plasma light in the same direction;

a camera lens for receiving light reflected from the multi-surface mirror;

a first relay lens for converting the output beam of the camera lens into parallel light rays;

an interference filter for transmitting a specified wavelength component of the parallel light rays;

a second relay lens for focusing a light beam having passed through the interference filter;

an imaging element for converting an image formed of the focused beam into a video signal;

correction means for calculating the intensity distribution of the radiation from the to-be-measured object and the intensity distribution of the plasma light, on the basis of the video signal, and for correcting the intensity of the radiation by the intensity of the plasma light from the result of calculation, to determine the correct intensity of thermal radiation of the to-be-measured object; and

calculation means for calculating the temperature of the to-be-measured object from the intensity of thermal radiation thus obtained.

4. A temperature measuring apparatus utilizing radiation as claimed in claim 3, further comprising drive means for tilting the light receiving surface of the interference filter to enable the interference filter to transmit a plurality of wavelength components of the radiation from the to-be-measured object.

5. A temperature measuring apparatus utilizing radiation as claimed in claim 4, wherein in order to measure appropriate wavelength components of the radiation from the to-be-measured object, the light receiving surface of the interference filter is tilted on the basis of data from a data base.

6. A method of measuring the temperature of a to-be-measured object placed in a plasma by using a radiation thermometer, comprising the steps of:

measuring the intensity of radiation from the to-be-measured object nd the intensity of plasma light, in different directions at the same time;

correcting the measured value of intensity of the radiation by the measured value of intensity of the plasma light, to determine the intensity of thermal radiation of the to-be-measured object; and

calculating the temperature of the to-be-measured object from the intensity of thermal radiation thus obtained.

7. A method of measuring the temperature as claimed in claim 6, wherein the step of measuring the intensity of radiation from the to-be-measured object and the intensity of plasma light, in different directions at the same time includes utilizing:

a multi-surface mirror for receiving radiation from the to-be-measured object placed in the plasma and the plasma light, in different directions at the same time, to reflect the radiation and the plasma light in the same direction;

a camera lens for receiving light reflected from the multi-surface mirror;

a first relay lens for converting the output beam of the camera lens into parallel light rays;

an interference filter for transmitting a specified wavelength component of the parallel light rays;

a second relay lens for focusing a light beam having passed through the interference filter; and

an imaging element for converting an image formed of the focused beam into a video signal.

8. A method of measuring the temperature of a to-be-measured object placed in a plasma by using a radiation thermometer, comprising the steps of:

comparing light having merely passed through the plasma, with light which has passed through the plasma and is then reflected from the to-be-measured object, to calculate the reflectivity at the surface of the to-be-measured object; and

correcting the temperature of the to-be-measured object measured by the radiation thermometer, by using the calculated reflectivity, to determine the true temperature of the to-be-measured object.

9. An imaging spectral analyzer provided with measuring means for measuring the intensity of radiation from a radiator placed in a plasma and means for determining the light intensity distribution on the radiator on the basis of the intensity of the radiation obtained by the measuring means, wherein the measuring means includes a first lens for receiving radiation from the radiator and plasma light, a second lens for converting the output beam of the first lens into parallel light rays, a third lens for focusing the parallel light rays, and an interference filter disposed rotatably between the second lens and the third lens.

10. A imaging spectral analyzer according to claim 9, further comprising a polarization filter disposed on the optical path of the analyzer so as to be able to turn on the center axis of the optical path, and drive means for rotating the polarization filter.

11. An imaging spectral analyzer as claimed in claim 9, wherein the radiator includes a multi-surface mirror and the first lens includes a camera lens for receiving light reflected from the multi-surface mirror.

12. An imaging spectral analzyer provided with a camera lens for receiving an image of a radiator, a first relay lens for converting the output beam of the camera lens into parallel light rays, an interference filter for transmitting a specified wavelength component of the parallel light rays, a second relay lens for focusing a light beam having passed through the interference filter, an imaging element for converting an image formed of the focused light beam into a video signal, and control means for converting the video signal into image information, all of the camera lens, the first relay lens, the interference filter, the second relay lens and the imaging element being disposed on an optical path;

wherein the interference filter is made up of two filter plates which are perpendicular to each other and have different transmitted wavelengths, and the interference filter is rotated by driving means so that one of the filter plates is pependicular to the parallel light rays.

13. A spectral surface analyzer according to claim 12, further comprising a polarization filter disposed on the optical path of the analyzer so as to be able to turn on the center axis of the optical path, and drive means for rotating the polarization filter.

14. An apparatus comprising:

measuring means for measuring an intensity of radiation from a to-be-measured object placed in a plasma and an intensity of a plasma light, in at least two different directions at the same time;

means for correcting a measured value of the intensity of the radiation by the measured value of the intensity of the plasma light to determine a correct intensity of thermal radiation of the to-be-measured object on the basis of the measured values being obtained by the measuring means; and

means for calculating the temperature of the to-be-measured object from the correct intensity of thermal radiation thus obtained.

15. An apparatus as claimed in claim 14, further comprising:

control means for controlling the temperature of the to-be-measured object measured by the temperature measuring apparatus; and

sputtering means for sputtering a substance to form a film on the to-be-measured object, the temperature of the to-be-measured object being controlled by the control means so that the film formed on the to-be-measured object is homogeneous.

16. An apparatus as claimed in claim 15, wherein the means for measuring the intensity of radiation from a to-be-measured object placed in a plasma and the intensity of plasma light in different directions at the same time includes:

a multi-surface mirror for receiving the radiation and the plasma light and reflecting the radiation and the plasma light in the same direction;

a camera lens for receiving light reflected from the multi-surface mirror;

a first relay lens for converting the output beam of the camera lens into parallel light rays;

an interference filter for transmitting a specified wavelength component of the parallel light rays;

a second relay lens for focusing a light beam having passed through the interference filter; and

an imaging element for converting an image formed of the focused beam into a video signal.