Optical system and method for sample analyzation

• US 5,051,602 A
• Filed: 12/14/1990
• Issued: 09/24/1991
• Est. Priority Date: 03/02/1990
• Status: Expired due to Term

• Current Assignee: Thermo Electron Scientific Instruments LLC (Thermo Fisher Scientific Incorporated)
• Original Assignee: Spectra-Tech, Inc. (Thermo Fisher Scientific Incorporated)
• Inventors: Messerschmidt, Robert G., Sting, Donald W., Reffner, John A.
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): ALLEN, STEPHONE B
• Application Number:
  US07/627,730
• Time in Patent Office: 284 Days
• Field of Search: 250/216, 250/237 G, 250/571, 250/572, 350/525, 350/620, 350/622, 356/317-319, 356/445-448
• US Class Current: 250/559.16
• CPC Class Codes: G01N 21/4738 Diffuse reflection precedence is given to G01N21/55 - G01N21/57 if specular component is taken into consideration, e.g. also for testing fluids, fibrous materials
• CPC Class Codes: G01N 21/55 Specular reflectivity

Abstract

An optical system, apparatus and method for analyzing samples includes a radiant energy source, a first mask, a first mirror system, a sample plane, a second mirror system, a second mask and a detector. The first and second masks are respectively positioned along the optical path of the system in the same or different Fourier planes and/or conjugate planes thereof. The first mask has at least one inlet aperture with the relative position thereof in the first mask determining the angle of the energy incidence onto the sample. The second mask has at least one outlet aperture therein passing radiant energy therethrough which has been reflected from or transmitted through the sample at a preselected angle determined by the relative position of the second aperture in the second mask. Numerous first and second masks respectively having inlet and outlet apertures at different radial and/or circumferential positions may be used in the optical system to perform many types of analyses without moving or specially preparing the sample.

Claims

1. An objective system for selectively controlling an aperture of a radiant energy optical path passing therethrough both to and from a sample being analyzed at a sample plane comprising:

a connecting tube adapted to be removably secured to a sample analysis instrument;

a guide holder means at least partially surrounding the connecting tube and being supported thereby, the guide holder means having a guide slot therein;

a secondary optic of a Cassegrain mirror objective supported along the center line of the optical path by the guide holder means;

an outer ring supported by the guide holder means;

a primary optic of a Cassegrain mirror objective supported by the outer ring concentrically about the centerline of the optic path and optically cooperating with the secondary optic;

a slide means slidably received in the guide slot and having at least one receptacle means therein;

removable mask means at least partially received in the slide receptacle means and being positioned in the optical path at a Fourier plane thereof adjacent the Cassegrain mirror objective when the slide means is properly positioned in the guide slot, the mask means having inlet and outlet apertures, passing radiant energy therethrough at selected radial positions in the Fourier plane to control the incident angle of the radiant energy onto the sample after passage through the objective, the outlet apertures passing radiant energy therethrough at selected radial positions in the Fourier plane to control the angle of reflected or emitted energy travelling from the sample through the objective and outlet apertures to a detector.

2. The optical system of claim 1 further including adjustment means to adjust the objective relative to the center line of the optical path and/or the primary optic relative to the secondary optic.

3. The optical system of claim 1 wherein the removable mask means includes a plurality of masks having different configurations of inlet and outlet apertures to allow a multitude of different analyses to be run on the sample with different angles of incidence being used and different angles of reflection, transmission or emission being detected.

4. The optical system of claim 3 wherein the slide means has multiple spaced receptacle means thereon respectively receiving different masks to allow those masks selectively to be slid into and out of the optical path.