| 摘要 |
PURPOSE:To automatically carry out the positioning of a disk type object by providing a rotatable holding member which holds a disk type object for the positioning of a disk type object in the rotating direction. CONSTITUTION:A rotating plate 13 is moved downward after the positioning in the X and Y directions of mask 4 and an attracting pad 15 is attracted on the surface of mask 4. The lower cover 2 of cassette is shifted by the fork 1 until the sufficient space can be obtained between the mask positioning mechanism and the lower cover 2. An arm 17 is rotated, causing the theta direction position detection sensor 18 to move the lower part of circumference of mask. When the mask 4 is rotated by the rotation of rotating plate 13, amount of light detected by the reflection type sensor 18 changes when the theta direction position detection pattern 21 passes on the reflection type sensor. Therefore, the theta direction position of mask can be detected freely by fixing the sensor to the desired position. |
