Browse Prior Art Database

Fiber Optic Alignment Mask for Cathode Ray Tubes

IP.com Disclosure Number: IPCOM000105975D
Original Publication Date: 1993-Sep-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

McNamee, G: AUTHOR

Abstract

Disclosed is a means by which parallax errors inherent in Front Of Screen (FOS) alignment masks of CRTs can be eliminated by using Fibre Optic Light guides embedded in the mask.

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This is the abbreviated version, containing approximately 56% of the total text.

Fiber Optic Alignment Mask for Cathode Ray Tubes

      Disclosed is a means by which parallax errors inherent in Front
Of Screen (FOS) alignment masks of CRTs can be eliminated by using
Fibre Optic Light guides embedded in the mask.

      At present FOS geometry is set using alignment masks positioned
over the test pattern.  Alignment graticules or tramlines etched on
to the mask indicate to the operator the final position of the
geometry pattern.  If the operator's eye is not directly in line with
the graticule and the test pattern below it then parallax error can
result.  Current methods employ reflective tape or mirrors set around
the tramlines which help to ensure that the operator's eye is
directly above the test pattern.  This requires considerable head
movement by the operator during the setup process.  The technique is
also prone to misuse by setup operators due to different
interpretations of the setup technique., e.g., some operators may
close one eye, others may keep both eyes open which can lead to
different results using this technique.  Fig. 1 illustrates the
present method.

      Fibre Optic waveguides consist of several thousand individual
fibres sheathed in multi-layer protective casings.  Such a
construction possesses useful properties that can be exploited in
many applications.  In this application the light guide is used to
transfer the test image from the monitor on to the surface of the
setup mask in the exact plan as the alignmen...