Abstract:
The invention concerns on-line electro-optical detection of wafer defects by illuminating a continuously moving wafer with a light pulse from a pulsed laser and imaging the moving wafer onto a focal plane assembly formed as a continuous surface of photo-detectors at the focal plane of the optical imaging system. The laser pulses are of duration significantly shorter than the pixel dwell time, such that there is effectively no image smear during the wafer motion. A fiber optical illumination delivery system, which reduces the effects of source coherence, is described. Other aspects of the system include a system for compensating for variations in the pulse energy of a Q-switched laser output, methods for auto- focusing of the wafer imaging system, and methods for removal of repetitive features of the image by means of Fourier plane filtering, to enable easier detection of wafer defects.
Abstract:
A spectrometer (100) includes a light source (102) providing output light (106) to the bundled input ends (108) of multiple light pipes (110). The light pipes (110) branch into sets (118) between their input ends (108) and output ends (114), with each set (118) illuminating a sample detector (126) (via a sample chamber (122)) for measuring light scattered or emitted by a sample, or a reference detector (128) for obtaining a reference/datum measurement of the supplied light, so that comparison of measurements from the sample detector (126) and the reference detector (128) allows compensation of the sample detector measurements for drift. Efficient and accurate measurement is further assured by arraying the multiple light pipes (110) in each set (118) about the input bundle (116) so that each set receives at least substantially the same amount of light from the light source (102).
Abstract:
The present invention is directed to solving the problems associated with the detection of surface defects on metal bars as well as the problems associated with applying metal flat inspection systems to metal bars for non-destructive surface defects detection. A specially designed imaging system, which is comprised of a computing unit, line lights and high data rate line scan cameras, is developed for the aforementioned purpose. The target application is the metal bars (1) that have a circumference/cross-section-area ratio equal to or smaller than 4.25 when the cross section area is unity for the given shape, (2) whose cross-sections are round, oval, or in the shape of a polygon, and (3) are manufactured by mechanically crosssection reduction processes. The said metal can be steel, stainless steel, aluminum, copper, bronze, titanium, nickel, and so forth, and/or their alloys. The said metal bars can be at the temperature when they are being manufactured.