| 摘要 |
PURPOSE:To make it possible to measure the vibration of a body, by detecting a speckle pattern by utilizing the fact that the speckle pattern is vibrated in the same direction as the vibrating direction of a lighted surface, and the amount of displacement is proportional to the amplitude of the vibration of the body. CONSTITUTION:A body 1 is vibrated in the directions of arrows, and laser light (a) is projected on the body 1 in the direction of an arrow. Scattered light is yielded from the lighted surface of the body by the projection of said laser light, and a speckle pattern is formed. Said pattern is vibrated in the same direction as the vibrating direction of the lighted surface. The amount of displacement is proportional to the amplitude of the vibration of the body. Two light sensors 21 and 22 are provided at the pattern yielding position. The speckle pattern, which is vibrated at two photoelectric planes is detected. An intrinsic DC component is included in the result. But only an AC component is taken out by providing a DC component removing circuit. In this detected waveform, when the speckle is present in the light receiving plane, the output becomes positive. When the speckle is not present, the output becomes negative. Since non-contact vibration measurement becomes possible, measurement at a high temperature part or a narrow part can be performed, and the range to be measured can be expanded. |
