Browse Prior Art Database

Increasing Lifetime and Reliability of CRT Displays

IP.com Disclosure Number: IPCOM000107358D
Original Publication Date: 1992-Feb-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 3 page(s) / 126K

Publishing Venue

IBM

Related People

Eagle, DJ: AUTHOR [+2]

Abstract

Disclosed is a method used to prolong the lifetime and reduce the failure rate of CRT displays which is fully compatible with existing system/display interface architecture. Attaching a display fitted with this invention to a standard system allows the system software to power off all or parts of the display as required, improving product life and reliability.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 51% of the total text.

Increasing Lifetime and Reliability of CRT Displays

       Disclosed is a method used to prolong the lifetime and
reduce the failure rate of CRT displays which is fully compatible
with existing system/display interface architecture.  Attaching a
display fitted with this invention to a standard system allows the
system software to power off all or parts of the display as required,
improving product life and reliability.

      Software exists that effectively blanks the screen when the
keyboard is unused for a certain period, preventing phosphur burn;
pressing a key restores the original image. Such software helps
improve CRT life but does not reduce the failure rate of the display.
Solutions exist to alert the user when the system unit had been
turned off but the display left powered on; typically, LEDs are made
to flash to alert the user to the condition.

      The proposed solution acts to improve both the failure rate and
the lifetime of the display without upgrading the basic electronic
components or the CRT.

      The concept is that the display has some additional logic
circuitry which is sensitive to a condition in which one or both of
the sync signals from the PC has stopped and yet the display is still
plugged in to the PC.  Such a situation exists in one of two cases.
First is when the PC is powered off, or if the PC is on but
the software has been programmed to kill the sync pulses.  It is
possible to stop the sync pulse trains by shutting down the CRT
controller by software, leaving the syncs as unspecified levels but
the AC components disappear.  Whether the display is still plugged in
to the PC is detected conventionally using the test line, held low
when the display is plugged in to the system unit.  If logic detects
a 'no sync and test line low' condition, then it powers down most of
the circuitry inside the display, reducing power consumption of the
display.  Only degauss PTC and standby circuitry are left active.
The CRT heater may remain powered at a lower level than normal.
Without the heater maintained, it may take some seconds for the image
to reappear when the display reverts to normal mode.

      The PC could contain software that stops the sync pulses after
a certain period of time has passed since the last keystroke,
typically five minutes.  The display senses that the syncs had
stopped and that the display was still plugged in to the PC.  After a
suitable delay (to prevent accidental triggering of the standby mode
during mode changing, etc.) the display would power down, leaving a
standby circuit and possibly reduced CRT-heater powered on. The
degauss PTC would be left powered on as it is likely that its
performance would degrade if subjected to an increased number of
power-on current surges.  Total power consumption of the display
would be less than...