[BRLTTY] Slightly OT, cleaning braille display cells

[Robin Williams]

Thanks for this informative reply Jason. 

  I'll keep it in mind.
	
Robin.
-----Original Message-----
From: brltty-bounces at mielke.cc [mailto:brltty-bounces at mielke.cc] On Behalf
Of Jason White
Sent: 03 January 2007 02:28
To: brltty at mielke.cc
Subject: Re: [BRLTTY] Slightly OT, cleaning braille display cells

On Tue, Jan 02, 2007 at 05:09:08PM -0000, Robin Williams wrote:
>   Sorry for the slightly off topic nature of this message. 

Actually, Dave took the ingenious step of liberally defining the topic of
the
list, which effectively eliminates most, if not all, of the acrimonious
debates about "off-topic posts" that arise in many other fora. Credit must
also be given to the BRLTTY community for being a smart and cooperative
group
of people.
> 
>   Do people on this list have any reccomendations about cleaning Braille
> display cells? It has come to my attention that after a few month's usage,
> some dots often remain in the up position when they should be down. I can
> imagine that the cells could get a bit dirty if the Braille display is
used
> often, as mine is. 

After a few years of use, or if dots start staying in the up position when
they shouldn't, the braille cells require cleaning. As I understand it, this
is a laborious and painstaking job that needs to be carried out by a
specialist who is experienced in the maintenance of piezoelectric cells. 
Here in Australia, for example, I am aware of only one expert who has the
necessary background, experience and skills to be entrusted with such a
task.

My understanding is that cleaning the cells properly involves removing each
of
the plastic caps covering the cells, then removing, cleaning and replacing
each pin. Apparently there is a lot of static electricity built up in the
ceramic piezoelectric element that drives each pin, which can cause serious
damage to the display if there is an electrostatic discharge - so whoever
cleans the cells has to be very careful. Also, some braille cells are easier
to maintain than others. For example, KGS have patented a design which
allows
the pins, and even individual piezoelectric reeds, to be replaced without
replacing the entire cell, which is a significant advantage given the high
cost of cells. This is one reason why I chose a braille display which (so I
am
told) uses KGS cells.

Thus my advice is to contact a representative of the manufacturer in your
country, or find an expert in the industry who is experienced in servicing
braille display cells, and if you think they're sufficiently reliable (after
checking out their reputation as far as possible), you can make arrangements
to have the cells cleaned.

Incidentally, it was very interesting to have the chance to examine actual
piezoelectric cells (outside a display, that is), which were exhibited by
KGS
at the CSUN Conference that I attended in Los Angeles, USA in 2003. 
They showed me cells from their graphics displays, which were similar in
principle to the cells found in a braille display, but with a design
allowing
for many more pins so as to represent graphic images. One of the cells
preserved the appropriate spacing to allow for text as well as images to be
shown.

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