JVC DLA-G20, Sales Manual, Page: 5 / 22

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Conventional projection methods: CRT projection tube
method and LCD (liquid crystal) method. The construction
and features of each method are outlined in Table 1.
The CRT method has been in use for a long time
and the characteristics of its input signals are excellent.
However, the higher the brightness, the larger the beam
diameter, resulting in degraded resolution. At the same
time, heat is produced when beams run into the phosphor
screen. As a result, brightness and resolution are limited,
resulting in an unsatisfactory tradeoff.
The LCD method offers compactness, light weight
and mass-production. However, when the resolution is
increased, the aperture ratio (area rate of effective pixel
section) is lowered, resulting in decreased brightness and
heat generation due to the light and heat conversion in
non-aperture section (ineffective pixel section).
As a result, brightness and resolution are limited,
resulting in an unsatisfactory tradeoff.
Even though both methods have been improved, they are
still subject to a tradeoff between brightness and
resolution. To maximize performance, projectors are often
stacked in multiple configurations.
The ILA projector solves the tradeoff between
brightness and resolution with a new method using a
spatial light amplification device (ILA device).
In order to maintain high performance, while achiev-
ing a more compact design JVC developed the D-ILA
method. As shown in Fig. 1, while the conventional ILA
method uses the CRT to write a picture, the D-ILA method
writes video signals directly and electrically to the device.
As a CRT and writing lens are not required, the
body of the projector can be greatly reduced, while still
achieving brightness of 2000 lumens — the highest in the
S-XGA full resolution class.
Outline of each projector method
D-ILA Method Present Condition and Subject
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D-ILA multimedia projector technical description
D-ILA multimedia projector offers both
high brightness and high resolution.
CRT
LCD
Input signal
Projection lens
CRT
Screen
•
Both the maturity degree and compatibility with
conventional systems are high.
•
With no pixel construction, this method is easily fit to
various signal forms.
•
To enhance the brightness, the amount of beam is
increased, resulting in the lowered resolution and heat
generation.
•
With a single panel, this method is easily fit to the mass
production.
•
As this is constructed with the pixel unit, the input signal
form is limited.
•
The light use efficiency is low.
•
To increase the resolution, the aperture ratio is lowered,
resulting in the lowered brightness and heat generation.
Input signal
Lamp
LCD panel
Projection lens
Screen
Methods Basic construction Features
CRT
for writing a picture
Input signal
Input signal
Writing lens
Projection
lens
Light source lamp
Light source lamp
Screen
Screen
PBS
(Polarized Beam Splitter)
ILA device
D-ILA device
Conventional ILA method
Newly-developed D-ILA method
High performance made compact!
Smallest in the S-XGA full resolution class!
PBS
(Polarized Beam Splitter)
Projection
lens
D-ILA method
present condition and subject
In world that is becoming increasingly digital, day by day, a
device capable of projection of high-resolution computer
graphics and digital video is becoming indispensable.
D-ILA is capable of producing a high-resolution, high-
contrast, big-screen image far brighter than conventional
projection systems and viewable from a wider angle than
ever.
The conventional direct-view-type display is also
changing to meet the demand for large-screen displays.
However, the size of these displays is limited. As a result,
demand for projectors which enlarge images optically and
reproduce them on a large screen is growing.
m
Table 1 Outline of projector methods
m
Fig.1: Comparison between the ILA method and D-ILA method
The performance characteristics required of a high
picture quality projector are listed below.
1. Large screen for an event hall
2. Higher brightness than in a movie theater
3. High resolution ready for high-definition TV
4. Input signal for multimedia
To satisfy these requirements, we developed the D-ILA
multimedia projector.
D-ILA method present condition and subject