Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/88—Investigating the presence of flaws or contamination
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
  • G01B11/303—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces using photoelectric detection means

Definitions

• the aim of the invention is to detect and localize very small disturbances in solid and liquid surfaces.
• the method is suitable for. For example, very good - in order to detect faults already during the production process (in-line) and to intervene in the process if necessary (regulation).
• the speed of the inspection is practically only limited by the mechanical movement of the material to be inspected.
• Figure 1 shows an example of a measuring channel.
• a measuring channel In principle, it is a modified Schlieren optics.
• the emitted light is parallellated from a point-shaped light source 1 with the aid of a parabolic mirror 2. It passes through a beam splitter 3, then the strip mirror 4 and falls perpendicularly onto the surface to be examined 7. If the surface is completely smooth and without any interferences, the light from 7 will travel back the same way through the open strips of «4 and at the beam splitter 3 divided and a part fall on the detector 5. If there is a disturbance 9 (elevation) on the surface 7, the light is deflected in the region of the elevation or its edges. Part of the light now falls on the playful strips 4 and is deflected to the detector 6. If the disturbance involves many very small increases v (roughness), then instead of one or a few light beams, many of these are deflected. It is therefore possible to use the described method to obtain information about the basic roughness as well as individual disturbances in surfaces.
• v
• FIG. 2 shows schematically the structure of a measuring channel with a possible arrangement of different filters for information processing.
• An alternating current generator 15 drives the punctiform lamp 1.
• the measuring channel 10 with the detectors 5 and 6 corresponds to the arrangement described above in FIG. cause a difference or a division of the two detector signals 5 and 6.
• the filters 12 and 13 can be narrowband amplifiers, tuned to the frequency of the generator 15.
• the evaluation circuit 14 removes the carrier frequency of the generator 15 and supplies the information about a possible disturbance under the measuring channel on the surface 7 to be examined.
• Figure 3 shows an arrangement like Figure 2, which has an additional detector 16 for detecting holes.
• the signal of 16 is processed in a similar manner to the signals of 5 and 6.
• Figure 4 shows the known method of synchronous demodulation.
• the generator 15 is coupled to the evaluation circuit 14.
• the information about the faults from the evaluation circuit 14 can be used for the monitoring, display, storage, regulation and automation by means of suitable electronic / information technology apparatus.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=4292308

Family Applications (1)

Country Status (4)

Cited By (3)

Families Citing this family (1)

Citations (5)

• 1985
  • 1985-12-17 CH CH536385A patent/CH669663A5/de not_active IP Right Cessation
• 1986
  • 1986-12-15 EP EP19870900036 patent/EP0250490A1/de not_active Withdrawn
  • 1986-12-15 WO PCT/CH1986/000175 patent/WO1987003957A1/de active Application Filing
  • 1986-12-15 AU AU67269/87A patent/AU6726987A/en not_active Abandoned

Patent Citations (5)

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