“BrightEra” |
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“BrightEra” microdisplay devices are
high-temperature polysilicon TFT transmissive
LCD devices that employ an
inorganic alignment film and new LCD
materials, which Sony succeeded in
developing ahead of the industry. This
inorganic alignment film and new LCD
materials are original technologies
developed by Sony to achieve the high
picture quality and high durability of the
reflective LCOS*1-type LCD device
“SXRD”*2 for AV projectors.
Conventional high-brightness projectors
generally used LCD materials that are
advantageous for increasing brightness
and the optimum organic alignment film
(polyimide) for aligning these LCD materials.
However, recent trends toward
brighter business projectors are accelerating
demands for the use of even brighter
light sources and smaller projector sizes.
By applying the “SXRD” technologies of
an inorganic alignment film and new LCD
materials to a high-temperature
polysilicon TFT LCD device, and optimizing
the design to support even higher
brightness, Sony has successfully developed
the “BrightEra” panels as devices
that can meet these demands.
“BrightEra” is the name given to high-temperature
polysilicon TFT LCD panels
that employ these new technologies.
“BrightEra” devices provide ultrabright,
clear images that were unavailable thus
far, and will shift projectors into a new
era of brightness.
The inorganic alignment film employed
in the new “BrightEra” panels is a core
technology that features a high resistance
to damage by light, allowing use of even
brighter light sources. Furthermore, the
deployment of various high brightness
technologies makes it possible to simultaneously
reduce the device size. This has
enabled development of a 0.79-type
device that can be used in a portable projector
that achieves the high brightness of
4,000 lm or higher.
*1: LCOS = Liquid Crystal On Silicon
*2: “SXRD” = Silicon X-tal (Crystal) Reflective
Display
“SXRD”and  are trademarks of Sony
Corporation.
Figure 2 Comparison of “SXRD” and “BrightEra” Structures |
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Main Features of “BrightEra” |
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■ Use of an inorganic alignment film enhances
light resistance, making it possible
to increase brightness.
Vastly improved resistance to damage by
light allows the use of more powerful light
sources, thus simultaneously achieving
both higher brightness and increased light
resistance. In addition, use of an inorganic
alignment film eliminates the need for
conventional physical alignment processing
by rubbing, which also enhances the
image evenness.
■ Introduction of a new drive system and
leading edge fine fabrication technology
realizes a high aperture ratio and high
picture quality.
The new double-speed field inversion
drive system expands the effective aperture
area of the LCD device by suppressing the LCD alignment variance caused
by voltage differences that formerly occurred
between each pixel line.
In addition, leading-edge fine fabrication
technology reduces the TFT element area
and electrical wiring pitch, which increases
the aperture ratio by approximately
20% compared to the conventional
method. Double-speed drive also halves
the TFT element leakage component that
occurs due to powerful illumination, and
vastly reduces flicker for specific patterns.
■ Normally black mode improves contrast.
Normally black mode employs the ideal
LCD molecule array for black display.
This makes it possible to achieve high
contrast with just the panel that formerly
required the use of optical compensation
elements in the conventional method. |
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Deployment of an Inorganic
Alignment Film |
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The light illuminated from the high-voltage
mercury lamps used in general
high-brightness projectors includes short
wavelength high-energy UV light. Normal
projectors have UV-cut filters to
eliminate this UV light, but a very small
amount of UV light still passes through.
The inorganic alignment film employed
in “BrightEra” devices does not easily
absorb the small amount of UV light that
cannot be eliminated by UV-cut filters,
and the use of inorganic material also
strengthens the molecular coupling in the
alignment film. This greatly increases reliability
with respect to long-term illumination
by intense light.
This allows the use of bright light sources
with even higher output, which makes it
possible to increase the projector brightness
without increasing the panel size. In addition, conventional organic alignment
films aligned the LCD materials by rubbing
the alignment film surface. However,
by changing to an inorganic alignment
film and modifying the film structure,
alignment force is manifest simply by
forming the alignment film. This eliminates
the need to physically process the
LCD alignment and provides an extremely
even image. |
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 New Drive System and
Leading-Edge Fine Fabrication
Technology |
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See
all articles with figures and tables.  |
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Vol.48 |
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