Dust Shield Needed for Monitor Screen

[rotatepod]

I helped a friend setup a computer in an environment
that has a lot of airborne dust. The monitor screen
pulls in dust like a shop vac. I've never seen anything
like it!

I purchased a piece of lexan mr10 (very durable) and
went into my shop to make a screen for the monitor.
After a few hours and several mistakes I tossed the
lexan into the scrap pile.

I've seen "privacy screens" for monitors which restrict
the viewing angle. My friend wants anyone who visits
his office to see the monitor. He uses the information
on this computer as a selling tool.

I found a couple of places that will make a custom
(and very expensive) screen for any monitor. Are there
any sources online that sell monitor screens at a
reasonable price?

[Bigglez]

I helped a friend setup a computer in an environment
that has a lot of airborne dust. The monitor screen
pulls in dust like a shop vac. I've never seen anything
like it!

Is the monitor a CRT or flatpanel (LCD)?
The latter avoids the high voltage field of
a CRT and should be less likely to attract
dust.

[rotatepod]

Its an LCD Monitor.

I don't know what's pulling the dust to the screen.
If you aim a powerful lamp at the monitor you
can see the dust flying through the air and landing
on the screen.

I keep a laptop computer in my shop. I've got a
fairly good dust collection system, but it doesn't
catch the very fine particles.

The companies that manufacture LCD monitors usually
provide instructions for cleaning the screen. When I
didn't know any better I used a polish that reduces
scratches in auto paint, plexiglass, etc. It never caused
any damage and dust would bounce off the screen!

I would never advise anyone to use this kind of product
on their monitor, because its impossible to know if it
would help or hurt.

[Janitor Tzap]

Its an LCD Monitor.

I don't know what's pulling the dust to the screen.
If you aim a powerful lamp at the monitor you
can see the dust flying through the air and landing
on the screen.

Hmm.....
It's building up a positive charge on the screen some how.
Some years ago you could get this little discharge unit that sat on your
CRT type monitor, and it drained away the static charge from the screen.
Basically a small carbon fiber brush that sat in the far corner of the screen.
This connected to a LCD screen, and series resistor before going to ground.
{The LCD screen would flash if there was a static charge present.}

I keep a laptop computer in my shop. I've got a
fairly good dust collection system, but it doesn't
catch the very fine particles.

The companies that manufacture LCD monitors usually
provide instructions for cleaning the screen. When I
didn't know any better I used a polish that reduces
scratches in auto paint, plexiglass, etc. It never caused
any damage and dust would bounce off the screen!

I would never advise anyone to use this kind of product
on their monitor, because its impossible to know if it
would help or hurt.

Yeah,
You have got to be careful with those polishes.


Signed: Janitor Tzap

[Bigglez]

It's building up a positive charge on the screen some how.
Some years ago you could get this little discharge unit that sat on your
CRT type monitor, and it drained away the static charge from the screen.
Basically a small carbon fiber brush that sat in the far corner of the screen.

That's interesting. The CRT front surface is charged
up once (as the HV power ramps up) Although the
beam energizing the phosphor is moving (and therefore
AC) the power for the CRT is DC, and many
kilovolts.

In effect there is a capacitor with the metal layer
on the inside of the glass as one plate and the
air on the outside of the glass as the other.

Once the outer plate is discharged, the same screen
will not recharge until the set is turned off (now the
inner plate is returning to ground or common, so
the outer surface charges to the opposite polarity).

(Play harp music as I recall doing some some
'experiments' on my grandparent's first colour telly,
when I was about eight years old).

I took the foil from a chocolate bar wrapper and
stuck it on the TV screen, and cycled the power.
This story doesn't have a bad ending, just a bored
kid playing around.

Later I made a electromoter from a jelly jar and
some paper clips (I didn't know the name
at the time, but saw one in a science TV show),
and 'discovered' that charge from the CRT face
kicked the two foil tabs in my jelly jar apart.

Later I found that another piece of foil on a
plastic bag could 'pick up' the CRT charge and
when taken to the jar meter over at the table,
also kicked the foil strips inside. The charge
from that area of the CRT screen was now gone!
(until the TV was powered off and on).

How do so many of us survive our early years?

Back OT:
For the drain wire/brush to work the outer surface
of the CRT needs to be conductive. In practice this
may be the case, due to deposits of airborne particles.

To remove the charge without contact would require
an AC field, possibly a stream of ions from an air
purifier (as seen at Sharper Image before they
closed their stores).

At this point it would be worth doing an experiment
with one. Any takers?

[jwax]

rotatepod- Are you getting more dust on the LCD screen than that which would accumulate on a flat, say, cardboard surface next to the screen?
In other words, is the LCD screen doing an attraction of dust, or are you just in a very dusty environment?
In the first case, an ionizing blower was mentioned- that should negate any surface charge on the screen. Maybe an anti-static spray?
If it's just a dusty room- get a maid.

[Externet]

Try a LCD monitor with LED backlights instead.
The typical CCFL backlights work with high voltage and can be causing the dust attraction.
Miguel

[haklesup]

Is the ground tab on the power cord attached. Do you have a 2 prong adapter or something. Dust attraction is common with CRTs but none of the LCD I have used were any dustier than the immediate surroundings.

I assumed (but can't substantiate) that the top layer on the LCD was just conductive enough to prevent this assuming that it wasn't a floating plate (capacitor).

If the equipment is properly grounded to a receptacle whose ground hole works then there may be a defect in the internal shielding of this unit. Was it ever disassembled?

Unlike a CRT which does have high voltage charge on the inside (due in part to the electron beam) which induces a charge on the outside which ultimately attracts the dust, an LCD is a low voltage device and any high voltage static charge must have been induced by something else external. No matter, the charge should bleed off through the internal shielding.

As Jwax suggested, antistatic spray cleaner is a good and cheap place to start. An ionizing blower could cost a significant fraction of the replacement cost of the monitor.

If its still new, I'd advide your friend to bring it back and get a better brand.

[MrAl]

Hello,


There is a chance that a small fan blowing at the screen might help.
This would be simple to try too. Perhaps from one side of the screen,
or maybe from the top.

The electrometer idea sounds interesting too, i havent experimented
with stuff like that in years and years.

[Bigglez]

The typical CCFL backlights work with high voltage and can be causing the dust attraction.

CCFLs operate from AC, ther eis no net charge
left on the screen. Plus the CCFL is behind the LCD.

[Bob Scott]

I purchased a piece of lexan mr10 (very durable) and
went into my shop to make a screen for the monitor.
After a few hours and several mistakes I tossed the
lexan into the scrap pile.

I transported two LCD monitors as airline baggage. I added square pieces of 1/16" Lexan between the original styrofoam packing and the cardboard boxes as extra insurance against screen damage, otherwise careless handling could cause a box puncture.

I cut the Lexan to size with a hacksaw. It only took a few minutes. I can't see how you had so much trouble doing the same thing. For your use, the solution is perfect. It will protect your plastic LCD screen from being scratched from constant cleaning.

Lexan is polycarbonate. It scratches easier than acrylic Plexiglas. But the acrylic is brittle and cracks when you try to work with it, so I think Lexan is a better choice.

[rotatepod]

WOW!!

I really didn't think there would be more than one or two replies
to my post. I apologize for not paying more attention to this
thread.

There used to be a plastics shop within easy driving distance from
my house. These guys called everything they had "plexiglass" or
just plain "acrylic." I really didn't care.

I deliberately purchased lexan mr10 because the info on this product
said it was more scratch resistance than most plastics. I'm definitely
not an expert on the chemical or physical properties of plastics.

Making a decent dust screen for a monitor may seem like a simple
project, but its not! You have to construct some kind of frame that
will allow you to attach the plastic to the monitor without voiding
the monitor warranty. I certainly didn't want to drill, glue, or do
anything to the monitor that would alter it's normal appearance.

My first thought was to make a series of clips that would hook over
the frame and clamp to the back of the monitor. Not possible. The
back of the monitor had too many curves and angles.

My friend actually came up with the best idea. Carefully drill holes
along the edge of the plastic. Long zip ties are passed through the
holes around the back of the monitor. This holds the dust screen
firmly against the monitor frame.

I did mess up the first piece of lexan. I made all sorts of dumb
mistakes because I was tired and wanted to finish the darn thing
fast.

[Bigglez]

Making a decent dust screen for a monitor may seem like a simple
project, but its not! You have to construct some kind of frame that
will allow you to attach the plastic to the monitor without voiding
the monitor warranty. I certainly didn't want to drill, glue, or do
anything to the monitor that would alter it's normal appearance.

If you're in the R&D phase of the project, why not
just wrap the screen in cling film?

It doesn't need hardware, is fairly clear (visibility),
and would trap the dust before it reached the CRT/LCD.

Don't wrap the whole monitor, which probably needs to
breath.

[Bob Scott]

Making a decent dust screen for a monitor may seem like a simple
project, but its not! You have to construct some kind of frame that
will allow you to attach the plastic to the monitor without voiding
the monitor warranty. I certainly didn't want to drill, glue, or do
anything to the monitor that would alter it's normal appearance.

My first thought was to make a series of clips that would hook over
the frame and clamp to the back of the monitor. Not possible. The
back of the monitor had too many curves and angles.

Home Depot in the US has flexible magnet tape. It's made of the same stuff as most fridge door magnets with one side "pressure sensitive adhesive" so you can attach it to a pane of clear plastic. Or, stick it on the LCD monitor and have a tin (steel) frame made around the window.

The semiconductor testing machines that my former employer manufactured used lexan access panels with magnet tape around the perimeter for temporarily enclosing machines in the clean room, before the installing "real" stainless steel door panels.

[Lenp]

Self adhesive hook & loop (Velcro) tape is sometimes a life saver! It can be used for mounting many things. A thin strip is easily cut from the wider tape.

As for the plastic curring, I use a fine blade, like a plywood blade and a wax stick lubricatant on a table saw. Don't go too slow or the blade will heat and distort, The chips need to carry off the heat. The blade will actually get wavy which most usually mucks up the operation. This same blade also works well with aluminum. I have have made many Bud Miniboxes more shallow by cutting the top and bottom heights then drilling new screw holes. The rip fence is great for this operation.

Make sure sure to wear safety glasses. The metal and plastic chips are way more aggressive than wood, I know first handed. I had an eye injury when an aluminum chip came off the blade, after I stopped cutting and the saw was coasting down.
Len