Surface relief measuring equipment
First Claim
Patent Images
1. Apparatus for measuring the thickness of a coating comprising:
- a turntable for supporting and rotating a flat substrate bearing a regularly sectored coating pattern, wherein in use, the centers of the coating pattern and the turntable are substantially coincident;
tracking means for bearing on a top surface of the patterned substrate, the tracking means vertically moveable in a direction perpendicular to the substrate;
means for moving the tracking means radially of the turntable;
a transducer operably connected to the tracking means for generating an electrical signal in response to vertical movement thereof;
a band pass filter for passing a component of the transducer electrical output at a frequency corresponding to the frequency of traversal of the pattern sectors by the tracking means;
and means for measuring amplitude of the filtered signal to provide an indication of coating thickness.
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Abstract
Surface relief analyzing equipment comprises a turntable and an audio frequency pick-up including a stylus. A substrate bearing the surface relief is rotated on the turntable at a fixed frequency and and analogue electrical signal produced at a pick-up transducer is passed through an a-d converter. Digital data is processed to produce an input to a display for registering a pictorial representation of the surface relief.
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Citations
8 Claims
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1. Apparatus for measuring the thickness of a coating comprising:
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a turntable for supporting and rotating a flat substrate bearing a regularly sectored coating pattern, wherein in use, the centers of the coating pattern and the turntable are substantially coincident; tracking means for bearing on a top surface of the patterned substrate, the tracking means vertically moveable in a direction perpendicular to the substrate; means for moving the tracking means radially of the turntable; a transducer operably connected to the tracking means for generating an electrical signal in response to vertical movement thereof; a band pass filter for passing a component of the transducer electrical output at a frequency corresponding to the frequency of traversal of the pattern sectors by the tracking means; and means for measuring amplitude of the filtered signal to provide an indication of coating thickness. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of measuring the thickness of a coating deposited on a surface by a coating process, the method comprising using said process to deposit onto a test substrate a regularly sectored coating pattern;
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supporting the test substrate on a turntable with a center of the coating pattern substantially coincident with a center of the turntable; bringing a tracking means to bear on a top surface of the patterned substrate, the tracking means being vertically moveable perpendicular to the substrate; rotating the turntable; simultaneously moving the tracking means progressively radially of the turntable; obtaining from a transducer operably connected to the tracking means an electrical signal corresponding to relative vertical movement produced in the tracking means by passage of the rotating regularly sectored coating pattern thereby; filtering the electrical signal to pass a component of the transducer electrical output at a frequency corresponding to the frequency of traversal of the patterned sectors by the tracking means; and measuring the amplitude of an output signal from the filter to provide an indication of the coating thickness.
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Specification