Fabri-perot spectroscopy method and apparatus utilizing the same

• US 4,850,709 A
• Filed: 02/27/1987
• Issued: 07/25/1989
• Est. Priority Date: 03/04/1986
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Shiba, Osamu, Kakuchi, Osamu, Yamamoto, Hironori, Hara, Kazuhiko, Ohtsuka, Masaru, Ban, Mikichi
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Koren, Matthew W.
• Application Number:
  US07/019,665
• Time in Patent Office: 879 Days
• Field of Search: 356/346, 356/352
• US Class Current: 356/454
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters

Abstract

Fabri-Perot spectroscopy method comprises a step of directing a light beam at a first refraction angle to a first Fabri-Perot interference plate and a step of directing a light beam transmitted through the first Fabri-Perot interference plate to a second Fabri-Perot interference plate at a second refraction angle, and Fabri-Perot spectroscopy apparatus comprises Fabri-Perot interference plates, a control device for changing a spacing between the Fabri-Perot interference plates, a first optical device for directing a light beam to the first Fabri-Perot interference plate at a first refraction angle, a second optical device for directing the light beam transmitted through the Fabri-Perot interference plate at a second refraction angle different from the first refraction angle to the second Fabri-Perot interference plate, and a seal for externally sealing the Fabri-Perot interference plates. Gas for protecting the Fabri-Perot interference plates is filled in the sealed space.

Claims

1. A Fabri-Perot spectroscopy method comprising the steps of:

causing a light beam to enter between two transparent plates at a first refraction angle for spectroscopically analyzing the light beam;

causing the analyzed light beam in said first step again to enter between said two transparent plates at a second refraction angle for further spectroscopically analyzing the light beam; and

causing the analyzed light beam in said second step still again to enter between said two transparent plates at a third refraction angle for still further spectroscopically analyzing the light beam, wherein one of the first, second and third refraction angles is different than another refraction angle.

2. A method according to claim 1 wherein two of the first, second and third refracting angles are equal.

3. A Fabri-Perot spectroscopy apparatus comprising:

a first transparent plate having a first surface and a third surface opposite to the first surface, said third surface including a reflection surface portion and a transmission surface portion; and

a second transparent plate having a second surface positioned to be opposed to said first surface of said first transparent plate and a fourth surface opposite to said second surface, said fourth surface including a reflection surface portion and a transmission surface portion, said first and second transparent plates spectroscopically analyzing a light beam caused to enter between said first and second surfaces;

whereby a light beam incident on the transmission surface portion of said third surface is caused to enter between said first and second surfaces, be reflected by the reflection surface portion of said fourth surface, again enter between said first and second surfaces, be reflected by the reflection surface portion of said third surface, still again enter between said first and second surfaces and be emitted through the transmission surface portion of said fourth surface.

4. An apparatus according to claim 3 further comprising means for varying the distance between said first and second surfaces.

5. An apparatus according to claim 3 wherein the reflection surface portions of said third and fourth surfaces are set to form a predetermined angle therebetween.

6. A Fabri-Perot spectroscopy apparatus comprising:

two transparent plates having two opposed surfaces for spectroscopically analyzing a light beam entering between said two opposed surfaces;

seal means for separating a space including a spacing between said two opposed surfaces from its environment; and

means for varying the distance between said two opposed surfaces, said varying means being disposed outside said separated space.

7. An apparatus according to claim 6 wherein said varying means includes a piezoelectric element disposed outside said spacing between said two opposed surfaces of said transparent plates.

8. An apparatus according to claim 7 wherein said seal means includes a heat insulation member.

9. An apparatus according to claim 6, wherein said opposed surfaces each include a reflection surface, and a gas is filled in said spacing to prevent deterioration of said reflection surfce.