Sunlight
Readable VBOND Technology
Available
on 6.4”
- 47” Displays
With
VarTech’s proprietary optical stack, controlling reflected
light significantly improves the optical performance of an LCD
display in any ambient lighting condition. See
our selection of VBOND LCD displays.
To
view an LCD monitor in high ambient light environments and/or
direct sunlight one must consider two important factors "luminance”
and "illumination". The luminance of an LCD display
is its brightness. Brightness is traditionally referred to as
a “nit” (Candela per meter/2), a unit of measure,
which is the amount of light energy coming out of the display.
Illumination is the amount of ambient light shining onto a display.
The readability of a display is dependant on the amount of light
that is being reflected off the display.
Light has the ability to travel through a variety of transparent
materials; such as air, glass, plastic, and even water. The material's
ability to transmit light is measured by its indices of refraction.
As light transfers from one material to another, such as air to
glass, the differences of the index of refraction will cause reflection.
In the case of an air-to-glass interface, the reflection will
be slightly less than 5% of the ambient light. All surfaces that
have an index “mismatch” will reflect cumulatively.
In the case of a standard glass or plastic protective overlay
window, typically used in front of the delicate LCD, there are
three surfaces with an index mismatch which will create a total
reflection of nearly 15% of the ambient light. If the total reflection
(in nits) is close to the displays brightness, the contrast of
the display will be reduced to the point where the display's readability
is reduced to unacceptable levels.
Reflective
Loss Experienced without VBOND Layer
|
|
|
Any
VarTech
monitor integrated with our VBOND process is equipped
with a UV protected solid, transparent bond. VarTech’s unique
optical bond eliminates reflection from the two internal layers
and utilizes an adhesive that matches the index of refraction
of the flat panel and the overlay. As well, the outer surface
of the protective window is chemically treated with anti-reflecting
coatings which matches the front surface of the glass with the
index of refraction of air. This combination reduces the total
reflection of the display and front cover glass to less than 2%
of the ambient light. A reduction of reflection of this level,
all but eliminates reflective loss in most ambient lighting conditions.
With reductions of this level, displays with 250 to 450 nits of
brightness (cd/m2), traditionally not viewable in direct sunlight,
will now be readable in very high ambient brightness or indirect
lighting conditions. This method also removes all air gaps, therefore
reducing the number of internal reflecting surfaces which can
lead to significant degradation of the LCD’s optical performance.
VarTech’s
VBOND process has many other benefits as well. By providing this
durable adhesion between the flat panel and the overlay we greatly
improve the displays’ ability to resist shock, vibration
and moisture. Additionally, with the eliminated air-gap we (1)
prevent heat build-up from a "greenhouse" effect, (2)
prevent fogging from moisture, and (3) eliminate any contamination
from dirt or obtrusive particles.
Additionally,
since VarTech supports a number of industrial, marine and military
markets there exists a number of add-on choices which can be integrated
into the VBOND process to address our customer’s specific
environmental needs.
These
features include:
• Contrast Enhancement filters
• Vandal Shields chemically strengthen
the display glass
• EMI Filters enable LCD compliance
with FCC and MIL-STD 461
• Touch Screens
• Transparent thermal heaters to extend
LCD operational temperatures
See
our selection of VBOND LCD displays
| 
