Apparatus for the simultaneous detection of ranges of wavelengths

• US 5,206,708 A
• Filed: 12/21/1990
• Issued: 04/27/1993
• Est. Priority Date: 12/21/1989
• Status: Expired due to Fees

• Current Assignee: Bernhard Platzer, Gunter Knapp
• Original Assignee: Bernhard Platzer, Gunter Knapp
• Inventors: Platzer, Bernhard, Knapp, Gunter
• Primary Examiner(s): Evans, F. L.
• Assistant Examiner(s): HANTIS, KAREN
• Application Number:
  US07/631,496
• Time in Patent Office: 858 Days
• Field of Search: 356/416, 356/418-420
• US Class Current: 356/416
• CPC Class Codes: G01J 2003/1226 Interference filters
• CPC Class Codes: G01J 2003/265 Read out, e.g. polychromator
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors

Abstract

An apparatus for the simultaneous detection of several ranges of wavelengths of polychromatic light radiation, using one detector for each detected range of wavelengths, includes an interference filter which filters the range of wavelengths to be detected out of the polychromatic light beam, and optical elements for guiding the polychromatic light beam to be detected. The optical elements include a first system of mirrors in the path of the incident polychromatic light beam for collimating it in a hollow-cylindrical manner, one mirror of the first system of mirrors being located at the center of the collimated light beam. The optical elements further include a second system of mirrors in the hollow-cylindrically collimated light beam that deflects this light essentially perpendicularly to the conceptual surface of the hollow cylinder and radially to the longitudinal axis of thereof. Photo-detectors associated with the particular deflection mirrors are mounted opposite the second system of mirrors to receive the deflected light. A common interference filter is mounted in the path of the beam between the deflecting mirrors and the photo-detectors, the deflecting mirrors and the associated photo-detectors being pivotable about the interference filter.

Claims

1. Apparatus for the simultaneous detection of several ranges of wavelengths of polychromatic light radiation, comprising:

optical guidance means for guiding an incident polychromatic light beam, said optical guidance means comprising;

means including a first system of mirrors located in the path of the incident polychromatic light beam for collimating said polychromatic light beam into a hollow-cylindrically collimated light beam, wherein one mirror of the first system of mirrors is mounted at the center of the collimated light beam, and

means including a second system of mirrors, said second system including a plurality of deflecting mirrors located in the path of the hollow-cylindrically collimated light beam, for deflecting the collimated light beam essentially perpendicularly in respect to a conceptual outer surface of a hollow cylinder defined by the collimated light beam and radially in respect to the longitudinal axis of the hollow cylinder;

a photo-detector for each range of wavelength to be detected, said photo-detectors being mounted opposite the deflecting mirrors; and

a common interference filter which filters the ranges of wavelengths to be detected out of the polychromatic light beam, said common interference filter being mounted in a path of the collimated light beam between the deflecting mirrors and the photo-detectors, the deflecting mirrors and the associated photo-detectors being pivotal about the interference filter;

said filtered ranges of wavelengths depending on the orientation of the deflecting mirrors in relation to the interference filter.

2. An apparatus as claimed in claim 1, wherein the deflecting mirros and photo-detectors are pivotably affixed to a wall of a hollow-cylindrical filter holder at the center of which is the interference filter.

3. An apparatus as claimed in claim 1, wherein the interference filter is located essentially in a shadow of the mirror of the first system of mirrors mounted at the center of the hollow-cylindrically collimated light beam.

4. An apparatus as claimed in claim 1, wherein the first system of mirrors compries:

means including a concave mirror with a central aperture for receiving the incident polychromatic light beam, means including a plane mirror located opposite the central aperture for reflecting the incident polychromatic light beam toward the concave mirror, and means for guding the collimated light beam past the plane mirror toward the second system of mirrors.

5. An apparatus as claimed in claim 4, wherein the plane mirror comprises a circular cross-section and wherein an outside diameter of the plane mirror essentially matches an inside diameter of the collimated light beam.

6. An apparatus as claimed in claim 5, wherein the deflecting mirrors are axially offset relative to the common interference filter.

7. An apparatus as claimed in claim 6, wherein each deflecting mirror and each associated photo-detector is mounted on a support plate rotatable about a longitudinal axis of the hollow-cylindrically collimated light beam.

8. An apparatus as claimed in claim 7, wherein the support plate comprises an essentially central circular clearance having a diameter which essentially corresponds to an outside diameter of a filter holder to which the support plates are affixed in rotatable manner.

9. An apparatus as claimed in claim 2, wherein nearly circumferential slots are present in the wall of the filter holder and are opposite light entry and exit surfaces of the interference filter, the slots opposite the light entry surfaces forming a guidance means for the deflecting mirrors and the slots opposite the exit surfaces forming passages for pencils of light issuing from the interference filter.

10. An apparatus as claimed in claim 1, wherein at least two interference filters are superposed at the center of the hollow-cylindrical collimated light beam, the interference filters being relatively rotatable about a common axis corresponding to an axis of the hollow-cylindrically collimated light beam.

11. An apparatus as claimed in claim 10, wherein each interference filter is located at a center of its own, coaxial, hollow-cylindrical filter holder, each holder having a wall to which the deflecting mirrors and associated detectors are pivotably affixed.

12. An apparatus as claimed in claim 1, whreein specular surfaces of the deflecting mirrors are formed each time by a slanted surface of a parallelipipedic prism of which the base surface essentially subtends a right angle to a longitudinal axis of the hollow-cylindrically collimated light beam.

13. An apparatus as claimed in claim 1, wherein the deflecting mirrors are radially displaceable in a plane perpendicular to a longitudinal axis of the hollow-cylindrically collimated light beam.

14. An apparatus as claimed in claim 1, wherein the interference filter is rotatably mounted about an axis of the hollow-cylindrically collimated light beam.

15. An apparatus as claimed in claim 1, wherein an interference filter support plate is rotatably mounted about an axis of the hollow-cylindrically collimated light beam.

16. An apparatus as claimed in claim 1, wherein pencils of light issuing from the interference filter are matched by means of optics in front of the photo-detectors to the particular size of the active detector surface.