Browse Prior Art Database

Flat CRT Set Up Mask/ Image Alignment Tool

IP.com Disclosure Number: IPCOM000106901D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Cromar, C: AUTHOR [+6]

Abstract

Disclosed is a device that provides a low-cost method of consistently establishing the position of a display raster edge within the bezel opening of a CRT display such that the specified geometric parameters for the displayed image size and position can be consistently met.

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Flat CRT Set Up Mask/ Image Alignment Tool

       Disclosed is a device that provides a low-cost method of
consistently establishing the position of a display raster edge
within the bezel opening of a CRT display such that the specified
geometric parameters for the displayed image size and position can be
consistently met.

      To achieve consistent assessment of the position of an image
edge as observed by multiple observers, this device eliminates the
observed image positional errors due to parallax effects during
viewing.  It comprises a flat Front of Screen (FOS) transparent
set-up mask to accurately assess the raster image position on any
CRT-based display, given that the mask is designed and manufactured
to reflect the geometry parameters of the display.

      Eliminated are parallax errors in assessment of raster image
edge position, convex distortion in horizontal and vertical tramlines
laid on the mask surface and simplification in the manufacture of
FOS-set- up masks due to removal of mask curvature to match that of
CRT, i.e., the mask is now flat.

      The mask 1 is fabricated from flat clear perspex sheet (or
similar material) as detailed in the figure.   Artwork or tramlines 5
on the mask 1 reflect the display front of screen (FOS) geometry
specification.  Both the nominal position and the allowable tolerance
for the raster edge position are marked on the perspex.  Similar
tramlines 7 are also marked across the center of the mask to indicate
the allowable tilt in performance of the CRT about the horizontal.

      In an embodiment a hig...