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Vertically Polarized Two-Domain Twisted Nematic Liquid Crystal Display

IP.com Disclosure Number: IPCOM000110754D
Original Publication Date: 1994-Jan-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 4 page(s) / 84K

Publishing Venue

IBM

Related People

Saitoh, Y: AUTHOR [+2]

Abstract

Disclosed is a backlit twisted nematic liquid crystal display (TN LCD). The light from this LCD oscillates along the vertical axis, and the contrast ratio of this LCD is superior to the conventional one in right, left, and up viewing zones.

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Vertically Polarized Two-Domain Twisted Nematic Liquid Crystal Display

      Disclosed is a backlit twisted nematic liquid crystal display
(TN LCD).  The light from this LCD oscillates along the vertical
axis, and the contrast ratio of this LCD is superior to the
conventional one in right, left, and up viewing zones.

      To obtain horizontally symmetrical optical performance,
conventionally, the rubbing directions of both entrance and exit
alignment layers are placed 45 or 135 degrees to the horizontal
direction.  Transmission axis of the exit polarizer is also placed 45
or 135 degrees to the horizontal direction.  This configuration has
two disadvantages:

1.  With polarized glasses, for example, driver's sunglasses or VDT
    eye-guard glasses, LCD screen shows poor performance, because the
    transmission axis of the polarized glasses is 45 degree to that
    of the exit polarizer.

2.  Optical performance is worse in most important directions,
    vertical (up and down) and horizontal (right and left) viewing
    directions.

      To solve these problems, first we proposed to apply
multi-domain TN technique [1]  to divide each pixel into two or more
sub-pixels of which optimal viewing directions are substantially
45 degrees from the vertical axis.  For example, Fig. 1 shows the
rubbing directions of conventional single-domain 90-degree TN
(SD90TN), two-domain 90-degree TN (TD90TN), vertically polarized
two-domain TN (VPTDTN-1), and a...