Browse Prior Art Database

CRT Mounting Method for Single Part Bezels

IP.com Disclosure Number: IPCOM000110964D
Original Publication Date: 1994-Jan-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 4 page(s) / 90K

Publishing Venue

IBM

Related People

Beeteson, JS: AUTHOR [+2]

Abstract

Disclosed is a design which accommodates the display industry standard CRT glass-to-lug dimensional tolerances for CRTs fitted to a single-part bezel. The low cost solution eliminates distortion and twist forces acting on the bezel and has a higher resistance to creep due to serrations incorporated on the bezel-mounting posts.

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This is the abbreviated version, containing approximately 52% of the total text.

CRT Mounting Method for Single Part Bezels

      Disclosed is a design which accommodates the display industry
standard CRT glass-to-lug dimensional tolerances for CRTs fitted to a
single-part bezel.  The low cost solution eliminates distortion and
twist forces acting on the bezel and has a higher resistance to creep
due to serrations incorporated on the bezel-mounting posts.

      The industry standard manufacturing tolerance for the dimension
between the CRT lug-mounting surface and the glass datum points is
plus/minus 2mm.  There is also a small additional variation of the
four lugs in relation to each other relative to a theoretically flat
plane.  A further tolerance between the bezel-mounting posts and the
bezel aperture flange must be considered.  Thus it is difficult to
obtain a good bezel to glass fit at an economical cost, unless some
bezel distortion is accepted.

      To obtain a good fit between the CRT glass and display bezel,
it is necessary to (i) procure CRTs with smaller tolerances, or (ii)
add spacers or adjuster screws under the CRT lugs, or (iii) design
the bezel such that when the subject dimension is on minimum
tolerance the glass is just in contact with the aperture flange and
the lug-mounting surface is also just touching the bezel-mounting
post surface.

      In case (i) above, display manufacturers have in the past been
able to procure CRTs with a slight reduction in subject tolerances,
but CRT suppliers are unable to accept a spec of less than plus/minus
2mm.  In case (ii), significant parts cost and assembly time are
incurred.  In case (iii), distortion of the bezel occurs that
increases as the tolerance changes from min to max.  This spoils the
fit between the bezel and the rear cover of the display.  The problem
is exacerbated when the outside flange of the bezel is shallow.

      The disclosed design proposes to change the four CRT lug-fixing
surfaces from the usual forward facing design (Fig. 3) to side facing
designs (Figs. 1 and 2)....