Epson PX-8 - Page 100

REV.-A
• When the temperature further rises, the entire panel becomes completely black and no selected
dots are visible at all.
* After being exposed to an abnormally low or high temperature, the LCD panel normally restores
its original property by itself if it is left at the normal temperature for a while. If the panel is left
in an abnormal temperature range beyond a certain limit of time, however, the liquid crystal may
be permanently affected and the panel may not return to its original operating condition.
2.8.3 Circuit Operations
The LCD panel is structured as a 480 (horizontal) x 64 (vertical) dot matrix and dirven with eight
SED1120 X-direction (vertical) drivers and one SED1130 V-direction (horizontal) driver. The
SED1120 drivers, each of which can drive 64 dots, are assigned to eight X drive lines
X1 through X8, as shown in Fig. 2-77.
480 dots
r---------------------------~~-----------------------------~,
1
33 65
97
129 161 193 225 241 273
305
337
369
401 433 465
)
)
) )
\
)
)
) )
)
)
) )
)
)
)
J
32 64 96 128 160 192 224 240
272 304 336 368 400 432 464 480
64 Xl X2
X3
X4
X5 X6 X7 X8 Xl X2 X3 X4 X5 X6 X7
X8
SEDl130
Fig. 2-77 X- Y Drive Scheme
2.8.3.1 Chip Selection
64
dots
The eight SED1120 X-line drivers are cascaded as shown in Fig. 2-78. Data bits are transferred to
one of these eight driver chips, one at a time, by means of a chip-enabling method designed to
minimize power consumption.
Xl X2
X8
LP-~+-I
t-+---{ X3 rv X 7 >-- __ EI-H
XECL--~--------------~------------------------~
Fig. 2-78 SEDl120 Data Transfer Scheme
2-76