Hitachi, Ltd. (TSE:6501) today announced that the company has developed a new, 18.1-inch 
Super TFT LCD that uses Super-In-plane Switching (Super-IPS) to improve image quality.  
Super-IPS mode operation minimizes changes in how colors appear at different viewing angles, 
resulting in a picture quality on a par with that of a CRT display.  In October the Company will 
start shipping samples of the new display, which is capable of SXGA resolution (1280-by-1024 
dots).

Compared to Hitachi's current Super TFT LCDs, the new display provides improved contrast and 
color purity as well as a high response speed for the display of moving pictures.  This makes the 
display particularly suitable for the expanding market for DVD, digital cameras and other digital 
media products.


The increasing use in the workplace and home of PCs has generated an increasing demand for 
LCD monitors, which consume little electricity and do not require much space.  However, LCD 
monitors must deliver a picture quality more or less equal to that of a CRT monitor.  In 1996 
Hitachi became the first company to market a wide-viewing-angle Super TFT LCD that employed 
IPS mode ( Note 1).  Currently the Company markets 14.1-inch, 15-inch and 18-inch versions of 
the display.

As shown in Fig., when IPS is used in a Super TFT LCD, the viewing angle is increased and 
colors do not change so much depending on the viewing angle.  This is a very important 
characteristic in terms of color reproducibility in the context of displaying DVD and digital camera 
images and the like.

IPS mode provides far better viewing-angle characteristics than the twisted nematic (TN) mode 
system used in conventional TFT displays.  However, at certain viewing angles, IPS mode LCDs 
still exhibited more gray-scale inversion than a CRT, making whites appear yellowish or bluish. 
In response, the Super-IPS mode tackles this problem by introducing a zigzag electrode structure. 
This changes the orientation of the molecules that cause the shifts toward blue and yellow, greatly 
reducing the extent of the color changes (Figs. 2 and 3).  The result is that up to 0.02 UCS (Note 
2), Super-IPS mode provides a viewing angle of 160 degrees both horizontally and vertically, 
compared with 65 degrees vertically and 100 degrees horizontally for TN-mode LCDs and 130 
degrees vertically and 160 degrees horizontally for current IPS-mode LCDs.  Thus, the viewing-
angle performance of a Super IPS-mode display is on a par with that of a CRT display.

With respect to production processes, a difference between Super-IPS and TN mode is that 
Super-IPS requires only one rubbing orientation in the multiple-domain structures (Note 3), does 
not require special treatment of the orientation film, and does not involve the addition of new 
processes.  This makes it easy to use with existing equipment, with only the electrode design 
requiring modification.  The fact that it makes it possible to greatly reduce the viewing-angle 
dependency of color tones with a simple structure is a major feature.

Improvements to color purity and contrast are of critical importance for enhancing picture quality. 
The new display uses a color filter arrangement that boosts color purity by 50 to 60% compared 
to Hitachi's current Super TFT LCDs.  Similarly, contrast has been improved to 300, compared 
to 200 before.

For displaying moving pictures, another critical factor is high response speed.  Careful selection 
of the liquid-crystal materials and drive system modifications give the display a response speed 
of 30 ms. The technologies involved will gradually be incorporated into other TFT LCD products.
The Company plans to use Super-IPS in a 15-inch display.  With work now progressing to further 
increase response speeds, in 2000 it is also planned to release displays with response speeds of 
20 ms or faster.


Note 1:	In-plane Switching (IPS):
	Conventional TFT displays employ twisted-nematic (TN) liquid crystal mode in which, in the liquid-
	crystal cell, the nematic molecules line up parallel to the top and bottom plates.  In a twisted nematic 
	liquid crystal display, the long cylindrical nematic molecules in between the top and bottom plates twist 
	layer by layer so that the long axis of the molecules adjacent to the top plate is perpendicular to the long 
	axis of the molecules adjacent to the bottom plate.  The plates each have a transparent electrode.  When 
	these electrodes are used to apply a voltage vertically through the cell, the molecules reorient so that their 
	long axis is perpendicular to the electrode plane (i.e., to the surface of the glass plates).  However, when 
	the molecules are inclined at an angle, the contrast and color of the display vary depending on the viewing 
	angle.  With an IPS mode system, the lower electrode is used to apply a charge horizontally, or in-plane, 
	causing the molecules to rotate parallel to the plate.  This does mean that using the IPS mode requires 
	changes to the liquid crystal portion as well as to the design of the TFT electrode structure.  However, the 
	result is that there is less viewing-angle-based gray-scale inversion and deterioration in contrast ratio, and 
	brightness and color tone also exhibit very little viewing-angle dependency.
Note 2:	0.02 UCS:
	This refers to the chromaticity coordinates in the 1976 UCS chromaticity diagram as laid down by the CIE. 
 	It is a numerical way of expressing differentials in a uniformly perceived chromatic space, with a higher 
	value indicating a larger chromatic difference.
Note 3:	Multi-domain (split orientation): 
	A state in which there exist within the same pixel two or more regions (domains) in which the liquid-
	crystal molecules have different orientations.



Sample prices and shipping schedule
Product				Sample price		Start of sample shipments
18.1-inch Super-IPS Super	400,000 yen		October 1999
	TFT LCD