Thermal measuring and testing – Temperature measurement – In spaced noncontact relationship to specimen
Reexamination Certificate
1998-08-21
2001-05-22
Gutierrez, Diego (Department: 2859)
Thermal measuring and testing
Temperature measurement
In spaced noncontact relationship to specimen
C374S121000, C033SDIG002, C362S259000, C356S399000
Reexamination Certificate
active
06234669
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a device for contactless temperature measurement of an object with an optical system which images into the finite and a detector. In contactless temperature measurement it is indispensable in practical use that the measurement spot on the object to be examined should be rendered visible in a suitable way. U.S. Pat. No. 5,368,392 proposes the deflection of a laser beam onto a rotating deflecting mirror to draw a circle representing the measurement spot on the object. However, this sighting arrangement can only used in an optical system which images into infinity. In an optical system which images into the finite according, an image of the detector is reduced and then enlarged by the optical system along an optical axis onto a measurement spot on the object from the optical system to the so-called sharp point measurement spot. In the past, in order to identify the measurement spot in an optical system which images into the finite, an opening laser cone according to U.S. Pat. No. 5,368,392 was used for example, which has its origin in the optical system on the optical axis and intersects the actual beam path of the optical system once before and once after the sharp point measurement spot. Thus, apart from the two planes of intersection, the sighting spot thus produced merely constitutes an approximate representation of the actual measurement spot.
Another possibility consists of directing individual sighting rays from the outer periphery of the optical system onto the point of intersection of the optical axis and the sharp point measurement spot. The resulting sighting measurement spot reduces to 0 up to the sharp point measurement spot and then enlarges again. This solution also only shows the approximate size of the measurement spot.
In order to reproduce a more precise course of the beam path of the optical system it has also been proposed to provide a beam for the region between the optical system and the sharp point measurement spot and a further beam for the region thereafter. However, this means that in each case two sighting measurement spots of differing size, caused by the two sighting beams, are visible both before and after the sharp point measurement spot. This in turn means on the one hand that the allocation of the correct sighting beam presents difficulties in certain circumstances and on the other hand the light energy necessary for producing the sighting light must be divided over the two beams. Accordingly the intensity of the sighting measurement spot is also correspondingly lower.
SUMMARY OF THE INVENTION
The object of the invention, therefore, is to create a device for contactless temperature measurement which is simple to manipulate and in which the sighting spot corresponds substantially to the actual measurement spot.
This object is achieved according to the invention, in that each sighting ray is aligned obliquely with respect to the optical axis in such a way that the sighting ray can be used both before and also after the sharp point measurement spot to identify the measurement spot.
Both before and after the sharp point measurement spot the sighting rays merely delimit on the object to be examined a sighting spot which reduces up to the sharp point measurement spot and then enlarges again. By virtue of an alignment of the sighting rays which is adapted to the imaging optical system, the sighting spot which is represented corresponds substantially to the actual measurement spot both before and behind the sharp point measurement spot. The manipulation of the device is therefore conceivably simple, since only one sighting spot which corresponds substantially to the actual measurement spot is rendered visible on the object.
Further advantages and embodiments of the invention are the subject matter of the subordinate claims and are explained in greater detail with reference to the following description and the drawings.
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Kienitz Ulrich
Klonowski Uwe
Schmidt Volker
De Jesus Lydia
Gutierrez Diego
Raytek GmbH
Townsend and Townsend / and Crew LLP
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