Newport Corp. has received a US patent (6,642,680) for a means of preventing stepper motor vibration, called "chatter," without resorting to faster, more expensive microprocessors. Chatter is a mechanically induced vibrational resonance traditionally avoided by a technique called "microstepping," in which a given movement of the motor is broken down into a series of small microsteps. Newport's innovation involves interpolating four intermediate values between each microstep and storing these in the controller's dynamic memory, where they can be rapidly read out. The company said this effectively quadruples the number of microsteps sent to the motor without requiring a faster microprocessor. The method has already been implemented in the company's ESP300 three-axis stepper motor controller. . . . Ultratech Inc., a supplier of photolithography systems used to manufacture semiconductors and nanotechnology devices, announced it has received numerous single and multi-system orders for its Saturn Spectrum 3e gold-bump tool from customers in Japan, Taiwan and China, and a new customer in Korea. Ultratech said its advanced packaging lithography tools are increasingly being used in the manufacture of display-driver integrated circuits for LCDs used in flat-panel displays as the industry shifts from CRTs to LCD panels.
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