| 摘要 |
<p>PURPOSE: To provide a transfer mechanism, a positioning device having the transfer mechanism, and a lithographic device having the positioning device. CONSTITUTION: A transfer mechanism 1 for converting a rotary movement into a translatory movement includes an internal and an external coupling member which cooperate with double thread systems 19 made of a magnetizable material. The external coupling member 29 includes a series of permanent magnets which are polarized axially and provided at regular intervals between the individual threads 37, 39 of the thread system. As a result, the individual threads each form a common pole piece for the permanent magnets 61. Therefore, a maximum magnetic flux density is achieved along the portion of the thread system in which the permanent magnets 61 are arranged Further, a non-magnetizable member is imparted between the threads of the thread system 19, so that the mutually facing walls of the coupling members 3, 29 are smoothened and a static gas bearing 47 can be applied between the walls.</p> |
