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For CAD and desktop publishing
Philips Brilliance 21A
autoscan monitor
Announced by Philips in late 1994, the
Brilliance 21A is a radical new development
in computer monitors. Not only are all its
specifications such as convergence under
digital control but it even compensates for
variations in the Earth’s magnetic field.
By BOB FLYNN
Ever since this new range of monitors was released, they have been in
short supply but after a very long wait,
we finally received a sample unit to
review. It was quite an experience.
We have a number of large screen
monitors in the SILICON CHIP offices
but for sheer size, the Brilliance 21A
monitor puts them in the shade. It’s not
so much that it has a large screen but
its cabinet is quite bulky and heavy.
Its overall dimensions are 528 x 540
x 501mm (W x H x D). So you need a
large desk for one of these monitors
and you need two men to lift it safely
since it weighs 37 kilograms.
The Brilliance 21A has a 54cm,
flat, black matrix, square CRT with
a dot pitch of 0.28mm, currently the
best that can be made. The screen is
anti-reflection and antistatic treated.
Maximum resolution is 1600 x 1280
pixels although that does not tell the
whole story.
While many monitors can be
switched to 1600 x 1280, their resulting picture may not be useable. The
Brilliance 21A, on the other hand, has
been electronically tweaked to obtain
the very best picture that can be obtained from existing 0.28mm dot CRT
technology. In fact, it could be said the
picture quality is theoretically better
than is possible. We’ll see why, later.
As with all large screen monitors,
8 Silicon Chip
the Brilliance is an autoscan model
and will automatically cope with
horizontal scan rates from 30-82kHz
and vertical scan rates from 50-160Hz.
Video input is RGB analog and typical
sensitivity is 0.7V. Video bandwidth
is 150MHz and input impedance 75
ohms. Three modes of sync are accepted: composite sync on the green
line, separate com
posite TTL sync
(positive or negative) and separate TTL
Horizontal and Vertical sync (positive
or negative).
The monitor also has the following
features: (1) digital control of contrast
and brightness over the full screen,
the brightness uniformity being better
than 90%; (2) digital control of convergence so that it is better than 0.2mm
(typically 0.15mm) over the full
screen; and (3) automatic cancelling
of the earth’s magnetic field through
a magnetic sensor and a proprietary
circuit that maintains a constant magnetic field inside the monitor. This
ensures that distortions of the display
caused by changes of the position of
the monitor do not occur.
Power management
Naturally, this monitor has energy
saving features and they are quite
comprehensive. It is TCO 1992 Power
Management/Energy Star Power Management compatible. This requires a
VESA-DPMS compliant signal. With
screen saver programs, the power
consumption drops 10%. With computers with VESA Display Power
Management, the power consumption
drops from a maximum of 180W to
15W, after one hour without vertical
and horizontal sync signals. When
sync signals are restored, recovery to
normal operation takes less than 3 seconds. After a further one hour without
sync signals, the monitor switches to
its lowest power state, consuming a
maximum of 8W. Recovery time from
this state is the same as the normal
switch-on period. The power state in
these reduced modes is shown on the
LCD panel.
Storage in the monitor’s memory of
21 different graphic resolution files, 12
factory preset and nine user generated,
is possible. Software is supplied with
the monitor that allows the user to
adjust the image for the correct size
and centring and generate a correction
table for the control of convergence,
brightness and colour uniformity, if
the application is not covered by the
default files.
Black screen
Apart from the size, the first thing
that most people notice about this
monitor is the “blackness” of the
screen. It certainly has the blackest
screen we have seen. Apart from this
the 21A looks very much like any other
digital monitor. At the bottom centre
of the front is a yellow backlit liquid
crystal display, flanked on either side
by a group of four pushbuttons. Further to the right of these are controls
for brightness and contrast and the
power switch.
The buttons to the left of the display
are Function, Adjust (+), Degauss and
Adjust (-). The + and - buttons each
you need to store your mode
by pushing the channel select
button to select one of the user
file memories (13-21).
Error messages
If no connection can be made
between the monitor and your
computer, the LCD will display
an error message such as “Missing H sync”, “Missing V sync”
or “Missing H & V sync”, meaning that cables are improperly
connected or the computer is
not switched on. The messages
“V out of range” or “H out of
range” mean that the vertical or
horizontal scan frequencies of
your computer are outside the
monitor’s 50-160Hz vertical or
30-82kHz horizontal scan rates.
Five additional error messages
may be displayed to indicate
monitor faults.
Geometry & convergence
For our tests, the Brilliance
21A was connected to a 486DX
and used with programs operatThe model 21A is the top model in the Philips Brilliance range of monitors. It has
ing at various resolutions from
digital control of all picture parameters and automatic compensation for variations
800 x 600 to 1280 x 1024 pixels.
in external magnetic fields.
For the two highest resolutions,
the message “Mode not found”
allow adjustment of the geometry and
internal microprocessor. A two-posi- was displayed and so we went through
colour temperature through a scale of tion slide switch selects either 75-ohm the procedure for creating user gener0-9, indicated on the LCD. The buttons
input impedance or high impedance. ated files. The supplied software runs
to the right of the display are Memory With only one monitor connected to from Windows and involves linking
Select, Memory Store, Memory Recall
your computer this switch should be
selected channels to user tables. This
and Input select.
in the 75-ohm position. The high im- done, Geometry Adjust was carried
Pressing the Function button ac- pedance position should only be used
out. This entails adjusting the raster
cesses the following 10 functions if two monitors are connected to your to screen centre and setting the vertisequ ent iall y: Horizontal position, graphics card.
cal and horizontal borders to a width
Width, Vertical position, Height, ColAt switch-on the LCD panel displays depending on the resolution for which
our temperature, Pincushion, Pincush- the message “Wait...start up”, followed
the table was being made.
ion balance, Trapezoidal, Trapezoidal
by “F/W Release..(No.)”. Each of these
The next step is to Select Reference
balance and Language.
messages display for 1-2 seconds and Points. A green mark has to be moved
The colour temperature function are then followed by the message
to the top left of the screen and a secallows the choice of either a 9300° or
“Test in progress”. This message is ond green mark moved to the bottom
6500° white. A third choice allows displayed for 2-3 seconds while the right of the screen. The program then
the operator to set his own colour
monitor does its self checks. If the creates the correction table for brighttemperature by the adjustment of the
moni
tor recognises the timing sup- ness and convergence of the operating
red, green and blue mixture using the
plied by your video card as one of its
mode. The files so created should be
+ and - pushbuttons.
default modes the LCD will show the
saved to the hard disc so that the chanOn the rear of the monitor is a power
resolution being used. If it does not, nel settings can be restored if required
input socket (the monitor can operate then the message “Mode not found”
at a later date.
from 90-132VAC and 180-264VAC, 47- will be displayed.
Why do all this? Because the Philips
76Hz auto selected) and five BNC sockThis means that the current timing
Brilliance 21A is capable of much
ets for the signal connections. A 15-pin
is not stored though the monitor is better convergence than typical comMini D-Sub socket for video input is
working, with a proper screen display.
puter monitors but it has to be done for
also provided. A socket not normally You can elect to ignore the “Mode each and every screen resolution and
found on monitors is 9-pin Mini D not found” message but if you do
combination of horizontal and vertical
to provide a serial interface between you will not be able to optimise the
sync. With such a large screen and
the computer and the monitor’s own
convergence for your mode. Hence,
fine dot pitch, picture imperfections
September 1995 9
Fig.1: the schematic of the magnetic compensation circuitry in the Philips Brilliance 21A monitor. It continuously
compensates for any variations in external magnetic fields and ensures that optimum picture quality is maintained.
that would go unnoticed on smaller
monitors become critical, particularly
at the higher screen resolutions.
Magnetic field compensation
All of the fine attention to detail
in obtaining the best convergence,
geo
metry and uniformity of screen
brightness are subject to a big hazard
in the larger monitors. Simply rotating
the monitor changes its orientation to
the Earth’s magnetic field and thus the
electronic beams scanning the picture
are thrown off their optimised paths.
This happens in all monitors but again,
the larger the monitor, the worse the
effect on the picture, especially as far
as purity is concerned.
Philips has been really clever
here in introducing their innovative
Cyberscreen Technology, a high fal
utin’ name which embraces all the
21A’s digital control circuitry and,
more particularly, its magnetic field
compensation.
In essence, the 21A monitors the
magnetic fields acting upon the monitor and then produces a compensating magnetic field so that the high
convergence standard is constantly
maintained.
The schematic of Fig.1 shows the
general arrangement. A bridge of Hall
Effect devices is used to monitor the
magnetic fields and produce an offset
voltage. This voltage is converted to
10 Silicon Chip
a square wave by alternating current
pulses fed to the inversion coil. The
output square wave’s amplitude is
proportional to the magnetic field
strength. The square wave is AC coupled to the processing unit to remove
the offset and amplified. The signal
is then applied to the purity coils to
correct the monitor’s convergence – a
classic feedback circuit.
The correction signal is also rectified to produce a DC voltage proportional to the magnetic field. This voltage is applied to the degauss circuit
where any change in level triggers the
degauss circuit. Hence, at any time,
the Brilliance 21A may perform an
automatic degauss which you see as a
momentary picture distortion accompanied by the characteristic audible
twitch from the degauss coils.
The proof of the pudding
While it is easy to be overwhelmed
by the complexity of this monitor and
its operating procedures, the proof is
in the outstanding picture quality.
The monitor was used mainly with a
CAD program at a resolution of 1280
x 1024 pixels and the display showed
excellent geometry, even brightness
and good resolution. With my usual
monitor (a 20-inch colour monitor
with 0.31mm dot pitch), I need to
zoom in frequently on large drawings,
particularly when placing type; circles
that appear round at the centre of the
screen are not so when moved away
from centre. This is not the case with
the 21A. Type placement does not
require the same level of zoom and
circles are circles no matter where
they are placed on the screen. As noted
above, high resolution mode in one
monitor is not the same as on another
and this is where you really notice the
picture quality of the Brilliance 21A –it
is aptly named.
A minor irritation is the delay that
occurs when the resolution changes
within a program. For example, if the
program shells out to DOS, to perform
a print command, then the monitor
takes a noticeable time to find the
correct resolution file and show a correctly scanned picture. This delay is
longer than the switching time of the
relays in a multi-sync monitor.
As well as being ideal for desktop
publishing and CAD pro
grams, the
Brilliance 21A would appear to be
ideally suited to any program where
colour accuracy is paramount such as
in advertising production, textile and
fashion design, and so on.
At the time of writing, the Philips
Brilliance 21A is priced at $5270 plus
tax where applicable. Further information can be obtained from Philips
Business Electronics, Technology
Park, 3 Figtree Drive, Homebush, NSW
2140. Phone 1 800 658 086.
SC
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