|
In fact, Toppan sees the market for RPTVs changing rapidly from
CRT-based system to microdisplay-based systems. This agrees well
with the forecast published by Insight Media and McLaughlin Consulting
Group (Microdisplay Forecast &
Profile Report).
The FC-Screen is composed of three sheets: a Fresnel lens sheet,
a lenticular sheet and a protective front sheet, which can include
a vertical diffuser. Such screen construction is not uncommon,
but the design details for the FC-Screen are a bit different,
which accounts for its strong performance.
Overall, the Fresnel features a very fine pitch (0.1mm) of concentric
cone prisms to offer high resolution and brightness. This element
collects light from the projector, collimates it, and sends it
to the lenticular array. The lenticular lens array has a 0.155
mm pitch and is used to focus light through a series of black
stripes. Light is then diffused before passing out of the screen
providing a wide viewing angle.
The performance improvement comes from a reduction in optical
noise, which degrades contrast and causes color dispersion. Noise
rays are generated from internal reflections and refraction between
surfaces.
The FC-Screen uses a combination of lenticular lens design and
black stripe design to reduce this optical noise. Usually, the
lenticular lens shape is spherical, which causes rays off of the
optical axis to not converge, generating optical distortion, as
shown in the left drawing. Toppan changed the shape of the lenticular
lenses to an aspherical ellipsoidal shape to focus all the light
to a single point (right side of drawing). The result is a very
crisp and well-defined line of light emanating from each lenticular
element, instead of a poorly defined line of light surrounded
by optical noise.
Because the line of light is so well defined, Toppan can use much
wider black stripes in between each line of light. The stripe
blocks skew rays and absorbs ambient light coming into the screen
- both of which help to improve contrast.
|
