US 5,473,438 AGranted

Spectroscopic method and apparatus for measuring optical radiation

AssigneeRautaruukki Oy

InventorsHeimo Keranen, Pasi Pietarinen, Tapani Alajarvi, Veli Vali

Life of this patent

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Abstract

The intensity 2 of radiation coming from an object 1 to be measured and illuminated by collimated radiation is measured at several wavelengths by focusing the radiation, via a lens 4 and a planar mirror 6, on a detector group 3 having several detector elements (3a to 3d). The radiation coming from the object is directed by the lens and the mirror such that, by rotating the mirror, tilted at a small angle with respect to its axis 5, around this axis and by keeping the radiation on the surface of the mirror, the focus F of radiation is moved in a detector plane D along an uninterrupted circular path R crossing each detector element positioned substantially in the same plane and excited at a different wavelength.

Claims10

Dependent claims

A method of spectroscopically measuring optical radiation, in which the intensity of radiation coming from an object (1) to be measured and exposed to collimated radiation is measured at a plurality of different wavelengths by focusing the radiation, via optical means (4) and mirror means (6), on a detector group (3) comprising a plurality of detector elements (3a to 3d), comprising the steps of:

a) orienting the optical means to direct the radiation to a planar surface of the mirror means, said planar surface being tilted at a small acute angle (.alpha.) relative to a plane perpendicular to a rotational axis (5) of the mirror means,
b) rotating the mirror means around said axis such that a focus (F) of the radiation moves in and defines a continuous, repetitious path (R) in a detection plane, and
c) disposing the detector group with detection surfaces of the detector elements lying in said detection plane and in said path, such that the moving radiation focus repeatedly sweeps across the detection surfaces of the elements.

Dependencies are inferred from the claim text.

Facts

Application: 08/295,809Filed 2 Sep 1994
Priority: FI 92122120 Mar 1992
Granted: 5 Dec 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

G01J 3/02
Spectrometry; Spectrophotometry; Monochromators; Measuring colours: details
G01J 3/021
Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows: using plane or convex mirrors, parallel phase plates, or…
G01J 3/0235
Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows: using means for replacing an element by another, for…
G01J 3/0237
Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows: adjustable, e.g. focussing