Browse Prior Art Database

Differential Screw Micrometer

IP.com Disclosure Number: IPCOM000045924D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Wilson, AD: AUTHOR

Abstract

For generation of the small motions needed for alignment in X-ray lithography, a diaphragm is used to center and pre-load a threaded micrometer member in a differential micrometer arrangement.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 59% of the total text.

Page 1 of 2

Differential Screw Micrometer

For generation of the small motions needed for alignment in X-ray lithography, a diaphragm is used to center and pre-load a threaded micrometer member in a differential micrometer arrangement.

A simple device is disclosed for converting rotary motion into linear motion. The device consists of the very compact threaded unit shown in the figure. Outer shell 10 is of a material like brass and is threaded on the inside 11 with a pitch N. Inside this shell 10 is a rod 12 of brass-like material threaded with a pitch N-a. Connecting these two members together is a steel part l4 whose outside diameter 15 is threaded at pitch N while the inside 16 is threaded at pitch N-a. Rod 12 is threaded into part 14 such that the desired pre-load in the threaded parts occurs when diaphragm 18 connects shell 10 to rod 12, as shown. Probe 20 screws through diaphragm 18 into rod 12, attaching the diaphragm to rod 12. The diaphragm is attached to shell 10 with small screws. To make sure the threaded parts have the correct radial fit, shell 10 may be in split form with two 90» cuts extending about 2/3rds of its length. Shaft l4 can also be split but should have three 120 cuts to minimize problems when the two cuts engage as part 14 is rotated. Alternatively, rod 12 can be split and a wedge screw axially driven in from the shaft l4 end until the correct fit is obtained between rod 12 and shaft 14. In either approach, lock ring 21 is adjusted to make shell 10 c...