Other

Woo Jung Ahn

Heui Jae Pahk

Sung Wook Cho

A non-contacting measuring method for three dimensional micro pattern in a measuring object is disclosed. Three dimensional micro pattern of the surface of the measuring object is measured using blur of light. For measurement, a mechanism of an optical window with a slit is inserted between light source and the measuring object. The blurred image is captured by charge coupled device sensor based image frame grabber, and is analyzed in personal computers. All the values of the relative height differences are obtained in overall scanning measurement area of the measuring object. The relative height differences are the distances from the reference position to the other positions. The reference position is selected when its image is sharp in focus on the screen. At this time, images of the other positions except the reference position are blurred out of focus on the screen. Also, from the law of geometric optics and the geometric similarity of triangles, the relation equation between the height difference and the ratio of blurred image size to sharp image size can be constructed. When the size of the image of the reference position and the sizes of the images with the blurred image of the other positions are measured, all the height differences between the reference position and the other position can be calculated if the coefficients of the relation equation are evaluated.

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Seoul, South Korea

Woo Jung Ahn