Browse Prior Art Database

Registration of Magnet and Faceplate in Magnetic Matrix Display

IP.com Disclosure Number: IPCOM000122858D
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 80K

Publishing Venue

IBM

Related People

Beeteson, J: AUTHOR [+4]

Abstract

A finished Magnetic Matrix Display (MMD) requires reasonably accurate control of the distance between the magnet and the phosphor screen (the Z direction). It also requires much greater accuracy in the control of the alignment of each column of magnet apertures with their corresponding phosphor stripe trio (the X and Y directions). This includes any rotational displacement between the aperture column on the magnet and the stripes on the faceplate.

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Registration of Magnet and Faceplate in Magnetic Matrix Display

      A finished Magnetic Matrix Display (MMD) requires reasonably
accurate control of the distance between the magnet and the phosphor
screen (the Z direction).  It also requires much greater accuracy in
the control of the alignment of each column of magnet apertures with
their corresponding phosphor stripe trio (the X and Y directions).
This includes any rotational displacement between the aperture column
on the  magnet and the stripes on the faceplate.

      Both the magnet assembly and the display faceplate have thermal
coefficients of expansion.  These are reasonably well matched but
there will be some residual difference which will result in a change
in relative size over the permitted temperature range of the display.
Thus, the mounting system which holds the magnet to the faceplate
must be able  to accommodate these changes while keeping the magnet
in the correct relative position.  Failure to do so would result in
either:
  1.  Buckling of the magnet and, hence, Z direction misplacement
       if the magnet expands more than the faceplate.  Or,
  2.  Fracture/damage to the magnet and or faceplate if the magnet
       expands less than the faceplate.

      It is also important that the accumulation of tolerances be
minimized over the display area so that there is not a tendency for
image degradation (e.g., a purity error) to occur with changing
temperature.

      Fig. 1 shows a plan view of an improved magnet assembly
designed to address these problems.  The apertures are not shown.  A
hole and five slots, marked A and B to F respectively, form mounting
points for the magnet and pass through the whole magnet structure.  A
circular locating pin, Fig. 2, passes through A and is attached to
the display faceplate, thereby providing a...