Browse Prior Art Database

Combined Diffuser/Electro-Magnetic Compatibility for Flat Panel Backlights

IP.com Disclosure Number: IPCOM000115069D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Kerigan, S: AUTHOR [+3]

Abstract

Disclosed is a method of producing a combined light diffuser and EMC screen for flat LCD panel backlights. At no extra cost, two problems, light transmittance in a diffuser and provision of an EMC screen, are solved by a single component. Present diffusers provide no EMC shielding and separate EMC shields degrade light level.

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Combined Diffuser/Electro-Magnetic Compatibility for Flat Panel Backlights

      Disclosed is a method of producing a combined light diffuser
and EMC screen for flat LCD panel backlights.  At no extra cost, two
problems, light transmittance in a diffuser and provision of an EMC
screen, are solved by a single component.  Present diffusers provide
no EMC shielding and separate EMC shields degrade light level.

      Many flat panel displays use display technologies such as LCD
which are illuminated from behind by a backlight using one or more
fluorescent tubes.  These tubes radiate electrical interference which
can cause malfunction of the electronics within the display package.
The light intensity produced from the tube(s) is also non uniform.
Many manufacturers solve the non uniformity by interposing between
the tube(s) and the LCD panel a layer on which is deposited a
reflective material in a non uniform pattern such that the
transmission of light is lowest nearest to the fluorescent tube and
higher farther away from the tube to give a uniform illumination of
the LCD panel.  This pattern is usually formed by unconnected circles
of deposited reflective material which has no effect on any radiated
electrical interference produced by the fluorescent tube(s).  A
solution is described that combines the control of light intensity
with an effective screen for radiated electrical interference.

      Rather than depositing a pattern of unconnected spots or other
s...