A friction induced impulse noise of a plasma display panel (PDP) TV caused by a stick-slip phenomenon can be characterized as a single pulse sound or a burst sound with a duration time between 0.001 and 1 second, which can be occurred in all of constrained places such as screwed points or touching surfaces of two panels due to sudden temperature changes of a product. It is desired to find the source of noise in order to reduce magnitude and frequency, however, it is very difficult thing because of unexpected occurrence and short duration. This paper shows the technique to detect the source of a noise by using the Double Pulse Electronic Speckle Pattern Interferometry (ESPI) and the Laser Doppler Vibrometer (LDV). The double pulse ESPI can be well applied for a measurement of a dynamic deformation because it is able to catch a source of noise by observing the deformation field of a part caused by instantaneous slip in an instant of a emission of accumulated thermal energy in screwed points and touching surfaces. For a measurement of a microscopic deformation by a frictional surface slip occurred in a short duration within 100us, spatial phase shift method which works well for high speed application such as a deformation by a shock was used in double pulse ESPI. The firing signal of pulse ESPI can be received by triggering the impulse magnitude at a moment of a slip. Pulse ESPI can catch the deformation by a minute slip at a moment of noise, which contributed greatly to reduction of frictional noises in PDP TV.
Recently, micro gyroscope sensors are adopted in handy camcorders to compensate external shock or vibration such as hand shakes. In developing micro gyroscope sensors, vibration analysis is inevitable but not easy since the micro gyroscope sensors are too small. In this paper, non-contact full-field ESPI (Electronic speckle pattern interferometry) measurement technique is introduced in vibration analysis of micro gyroscope sensors. Resonant frequencies and ODS(Operational deflection shapes) are measured and compared to each other. It is found that structure and PCB molding mass is one of most sensitive factors in designing micro gyroscope sensors.