Browse Prior Art Database

Monitor Set-Up Fixture With Parallax-Free Alignment Patterns

IP.com Disclosure Number: IPCOM000100905D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Dickerson, JA: AUTHOR [+3]

Abstract

Today's conventional CRT alignment procedure requires the use of a template placed on the outside surface of the tube. Thus, the video alignment image written on the inside phosphor of the CRT is compared and adjusted with reference to the template spaced some distance away. Typical monochrome faceplate thickness is 0.4".

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 93% of the total text.

Monitor Set-Up Fixture With Parallax-Free Alignment Patterns

       Today's conventional CRT alignment procedure requires the
use of a template placed on the outside surface of the tube. Thus,
the video alignment image written on the inside phosphor of the CRT
is compared and adjusted with reference to the template spaced some
distance away.  Typical monochrome faceplate thickness is 0.4".

      During the alignment process, the operator repeatedly moves his
eyes between the CRT image and the yoke "trim" magnets.  With each
CRT eye fixation, the operator's head may move and a new reference
point for parallax correction must be established (Fig. 1).

      With the alignment fixture shown in Fig. 2, the template
alignment image is contained on a glass slide.  A slide projector can
project this image through the CRT faceplate to a focus at the
internal phosphor coating (the same image plane as the electron
beam).  The co-planar CRT-generated and projector-generated alignment
images can be externally viewed from all front-of-screen positions.

      Long term image stability of the alignment pattern can be
assured with a chrome-on-glass slide.  Optical distortion caused by
slide projector components can be measured. Corrections can be made
to the alignment slide artwork to compensate for any such distortion.

      Surface treatment on some CRT faceplates causes observable
reflections from both room ambient lighting and alignment pattern.  A
light c...