Abstract: The movable point source aperture used in conventional autocollimators for measuring tilt in a microscope's test sample is replaced by a fixed laser diode. The diode is turned on only for the duration of the tilt measurement, when light is delivered to the optical system of the microscope without obstruction of the normal illumination path. Similarly, the two switchable optical systems conventionally used in the metrology and tilt-measurement legs of the microscope are replaced by two permanently positioned independent imaging systems. Such optical decoupling of the two types of measurement eliminates the need for switching lens systems, which enables shorter measurement cycles, reduces mechanical vibrations, and simplifies hardware control mechanisms.

Abstract: An electronic template delineating distinct selected patterns corresponding to predetermined regions of interest in a sample part is used to limit analysis to those regions. The surface of the sample is first measured using conventional techniques. The data so acquired are used to identify boundaries between distinct regions, which are then compared to a predetermined pattern boundary in the template to find a best-fit match. The position of the pattern is then shifted to overlay the match, thereby automatically aligning the template's selected patterns with the regions of interest in the sample surface. As a result, profilometric analysis can be limited to the regions of interest. Correction factors are also assigned to each selected pattern in the template to account for physical differences in the corresponding regions of interest of the sample part that affect the profilometric measurement.

Abstract: The movable point source aperture used in conventional autocollimators for measuring tilt in a microscope's test sample is replaced by a fixed laser diode. The diode is turned on only for the duration of the tilt measurement, when light is delivered to the optical system of the microscope without obstruction of the normal illumination path. Similarly, the two switchable optical systems conventionally used in the metrology and tilt-measurement legs of the microscope are replaced by two permanently positioned independent imaging systems. Such optical decoupling of the two types of measurement eliminates the need for switching lens systems, which enables shorter measurement cycles, reduces mechanical vibrations, and simplifies hardware control mechanisms.

Abstract: In the process of converting an interferogram phase map to a surface profile, in the absence of tilt, a histogram of occurrences of phase values is created from phase data. Useful data are identified in bins with contents that exceed a threshold value. Where useful data wrap around the end of the histogram, a selected amount of phase shift is added to the phase data to move them all within the ends of the histogram. Where tilt is present, the phase data are differentiated to produce slope data and a histogram of occurrences of slope values is created. A best-fit amount of tilt is determined from the slope histogram by selecting the bin at the average between two points on the histogram curve that are a predetermined percentage of the maximum height of the curve. Thereafter, the best-fit tilt is subtracted from the original phase data to eliminate tilt.

Abstract: An electronic template delineating distinct selected patterns corresponding to predetermined regions of interest in a sample part is used to limit analysis to those regions. The surface of the sample is first measured using conventional techniques. The data so acquired are used to identify boundaries between distinct regions, which are then compared to a predetermined pattern boundary in the template to find a best-fit match. The position of the pattern is then shifted to overlay the match, thereby automatically aligning the template's selected patterns with the regions of interest in the sample surface. As a result, profilometric analysis can be limited to the regions of interest. Correction factors are also assigned to each selected pattern in the template to account for physical differences in the corresponding regions of interest of the sample part that affect the profilometric measurement.

Abstract: An electronic template representing the topography of a magnetic head being tested and delineating distinct patterns corresponding to particular regions of interest, such as ABS surfaces, is provided in order to limit analysis of the sample's surface to such regions. The outline of the slider positioned within the field of view of an interferometric microscope is identified by measuring the modulation of incident light at each pixel inside and outside the contour of the sample using the loci of perceivable fringe contrast as the criterion for establishing the location of such edges. Once the outline of the slider within the plastic tray is so established, the slider is shifted within the field of view to match the position of the template, thereby automatically achieving a precise alignment of the template with the boundary of the slider.