Browse Prior Art Database

Moire Pattern Input Tablet

IP.com Disclosure Number: IPCOM000090109D
Original Publication Date: 1969-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Koelsch, AC: AUTHOR

Abstract

Moire principles are used in a variety of applications, notably measurement in one direction. A computer input tablet using Moire principles to provide independent, simultaneous and precise digital representation of distances in the X and Y directions is constructed as follows. An index grating, comprised of orthogonal sets of lines 1 and 3 that are parallel and of uniform pitch, has placed upon it two scale gratings 5 and 7. Each scale grating has a set of lines 11 that are parallel and of the same uniform pitch as the index grating. Gratings 5 and 7 are mechanically joined together as indicated by dotted line 9 and positioned relative to the index grating such that grating 7 has an acute angle theta between its lines 11 and lines 1 of the index grating.

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Moire Pattern Input Tablet

Moire principles are used in a variety of applications, notably measurement in one direction. A computer input tablet using Moire principles to provide independent, simultaneous and precise digital representation of distances in the X and Y directions is constructed as follows. An index grating, comprised of orthogonal sets of lines 1 and 3 that are parallel and of uniform pitch, has placed upon it two scale gratings 5 and 7. Each scale grating has a set of lines 11 that are parallel and of the same uniform pitch as the index grating. Gratings 5 and 7 are mechanically joined together as indicated by dotted line 9 and positioned relative to the index grating such that grating 7 has an acute angle theta between its lines 11 and lines 1 of the index grating. Grating 5 has the same angle theta between its lines 13 and lines 3 of the index grating. The angle theta is exaggerated. Also, while not shown, the gratings 5 and 7 are mechanically linked to an operator's stylus such that X and Y motion of such gratings is allowed but rotational motion that alters theta is disallowed. Associated with each grating 5 and 7 is a conventional arrangement of light source, optics, light detector, electronic circuits and counter to count Moire fringes 15 and 17 on gratings 7 and 5 resulting from X and Y motion of such gratings over the index grating. Moire fringes 17 move only when grating 5 has a component of motion normal to lines 3 of the index grating....