Browse Prior Art Database

Location Independent Monitor

IP.com Disclosure Number: IPCOM000099603D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Dickerson, JA: AUTHOR [+2]

Abstract

Known monitors are considered location dependent for acceptable image quality. That is, each monitor is pre-set for operation in a specific part of the world. In addition, there are unique deflection yoke part numbers contained in the bill-of-material for northern and southern hemisphere display models. Image quality, as viewed by the user, is at best a compromise.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Location Independent Monitor

       Known monitors are considered location dependent for
acceptable image quality.  That is, each monitor is pre-set for
operation in a specific part of the world.  In addition, there are
unique deflection yoke part numbers contained in the bill-of-material
for northern and southern hemisphere display models.  Image quality,
as viewed by the user, is at best a compromise.

      A three-axis magnetic field detector is built into each monitor
(see Fig. 1).  The detector operates in one of two modes: (1) at time
of installation to characterize the local environment or (2) a
dynamic mode where there are locally generated fields, such as from
power lines or a fluorescent desk lamp.  Three magnetic field
components (X-Y-Z) are measured and digitized to serve as inputs to a
microprocessor.  Deflection parameters which are unique to this
monitor-type are stored in look-up tables.  A comparison is made
between magnetic field measurements and deflection parameters.
Resultant correction data drives three digital-to-analog (D/A)
converters for X-Y and Z compensation.

      Image rotation is accomplished with an additional toroidal-
wound coil located on the neck of the CRT (close to the gun
structure).  Details of one such design are given in Fig. 2.