| 摘要 |
A method for determining an arrangement of first and second objects such that a gap between the first and second objects becomes a predetermined gap includes the steps of forming a light transmitting entry window on the first object, forming a light transmitting exit window on the first object at such a position that light would enter through the entry window the second object, reflect on the second object or on the first and second objects, and then enter the first object if the first and second objects are arranged in parallel at the predetermined gap, introducing light to the entry window to provide the second object with the light, detecting an intensity of light from the exit window, and determining the arrangement for the predetermined gap based on the detected light intensity. |
