• No excessive load to the target measurement object with the non-contact measurement.

• The spatial resolution is high and multipoint measurement of minute object is available by focusing the laser spot into some µm.

• The standard output is [velocity], so conversion to the acceleration and the displacement is available with the only one time integrodifferential processing.

When the detector contacts to the target object such as the accelerometer, the [contact resonance] which is generated by the contact surface affection becomes a problem. The contact resonance is occurred when the vibration system is formed by the rigidity of the fixing point, including the vibration system of the contact surface and the mass of the accelerometer. This is a phenomenon of the resonance, which is occurred when the [spring] generates between the target object and the detector. The frequency which generates the contact resonance is changed depending on the fixing method. The guideline of the frequency values, when mounting the accelerometer with the screw (the most stable way of mounting) is around 20 kHz, and when mounting with the adhesive agent or the thin double-faced tape is around 10 kHz. This is the biggest reason that the accelerometer cannot be used for more than 20 kHz vibration measurement.

The non-contact vibration measurement of the laser doppler vibrometer enables the vibration measurement without any affect on vibration. The beam spot can be focused into some µm, so the measurement at the small and narrow area is possible. The standard measurement frequency range is 3 MHz (LV-1710), and can be increased to 20 MHz as an option. The system of simultaneous detection of the three axes directions is available.

When the laser doppler vibrometer processes the measurement (vibration) of the moving object, it is easy to use the [velocity] (m/s) for the measurement. When the [displacement] is used for the measurement of the minute vibration of the target object under the affection of the background noise, the waveform is difficult to observe. The displacement of the target object is embedded due to the large displacement of the background noise. To prevent this affection, the high performance vibration resistant table is necessary. On the other hand, when the measurement of the [velocity] output is used, the velocity value of the low frequency background noise is smaller than the vibration velocity of the target object, so the vibration waveform of the target object is easy to observe. The background noise is hardly affected, when the measurement of the high speed vibration object such as ultrasonic vibrator is processed with the velocity output.