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High-Resolution 2.2-Type QVGA (180 ppi) Low-Temperature Polycrystalline Silicon
System-on-Glass TFT LCD Display for Cellular Phones
ACX342BKM
Sony has now developed the ACX342BKM 2.2-type QVGA (180 ppi)
LCD module for cellular phones that achieves not only high color purity
with a color NTSC ratio of 60% and the high brightness of 300 nit,
but low power consumption (210 mW for backlight + LCD panel operation)
as well.
For the ACX342BKM, Sony refined their system display technology that
forms the whole LCD drive system on the glass substrate even further
to achieve both high resolution and the highest level of optical characteristics
at the same time. The result is an LCD display module that is
optimal for mobile applications. |
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ACX342BKM |
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* 5.64 cm (2.2-type) QVGA system display
* High brightness and high color purity
* Low power consumption
* Single 2.9 V power supply operation
* 16-bit RGB digital interface circuit |
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System Display Technology |
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The ACX342BKM is an LCD module that
includes Sony’s independently developed
system-on-glass technology, a technology
that forms, as a single integrated unit, all
the LCD drive circuits on the LCD panel
using Sony’s high-performance/high-reliability
low-temperature polycrystalline
silicon TFT devices. This technology can
incorporate, on the glass itself, all of the
RGB interface and drive circuits, including
a supply voltage generating circuit
(DC/DC converter) that can operate from a single 2.9 V power supply, a 16-bit RGB
digital interface circuit, reference drivers,
a timing generator, VCOM drivers, a
VCOM adjustment circuit, and other
power supply system circuits. (See figure
1.) This system-on-glass technology
makes it possible to drive the display by
mounting just 12 capacitor and resistor
components on the flexible PC board
(FPC) and also achieves high reliability
by reducing the number of connections
required. |
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High Brightness and High
Color Purity |
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By making the oxide film in the transistor
circuit thinner in a process technology,
Sony achieved a significant reduction in
the surface area of the pixel internal Cs
(supplementary capacitor) block. This
allowed Sony to achieve an extreme high
aperture ratio in the ACX342BKM, despite
the fact that it has the extremely fine
resolution of 180 ppi in a 5.64 cm (2.2-
type) QVGA display. By combining this
display with a high-intensity backlight,
Sony achieved a brightness level increased
to 300 nit.
The use of color filters that were optimized
for the spectral characteristics of
the white LED backlights made it possible
for Sony to achieve both higher transmittance
and higher color purity at the same
time. This means that the ACX342BKM
achieves both the high brightness of 300
nit and at the same time, an extremely wide color reproduction with a color
NTSC ratio of 60%. (See photograph 1.) |
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Low Power Consumption |
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At the same time as achieving the
industry’s highest level of optical characteristics,
namely a brightness of 300 nit
and an NTSC ratio of 60%, by adopting
the system display, process, and high-brightness
backlight technologies
described above, Sony was also able to
achieve the low power of 210 mW (with
the backlight on and the full display operating).
This corresponds to a roughly 33%
reduction when compared to earlier
system display LCD modules that have the
same characteristics. (See figure 2.)
This reduction in power consumption can
contribute to reduced battery drain in end
products. Thus the ACX342BKM is an
LCD module that is truly optimal for
mobile applications. |
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•••• Mr. NAGAI••••
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We refined Sony’s system display
and process technologies, which
have been evolving daily, even further
and incorporated the appeal
of those technologies into
our latest development, the
ACX342BKM. We packed both
Sony’s leading-edge technologies
and the efforts of all the team
members into the simple structure
of this device, and were able to
create a device that not only
achieves superb picture quality
and characteristics, but also
achieves high reliability as well. I
hope you will come to appreciate
the appeal of this device. |
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See
all articles with figures and tables.  |
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Vol.41 |
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