Touchscreens
 

I have recently tried a touchscreen on my navpod using it as a repeater for
my laptop for navigational purposes. Unfortunately it was a bit of a
disaster. Problems with steaming up, and poor brilliance and a lot of
reflections. It was fine at night or on a dull day, but who wants to sail
when its just about to p..s down with rain.
Does anyone have any experience of installing transreflective touch screens,
can you suggest suppliers (UK) and possible pitfalls

Thanks for any help

Phil,
I've never heard of a transflective touchscreen. A transflector needs
to be mounted on the rear of the displar, not on the front. In the
reflective mode they allow light that has passed through the to be
reflected back out. In the transmissive mode they allow light from a
back light to pass through the transflector. If you mounted it on the
front it would probably make the display harder to read, due to light
losses. It would also probably have lots of glare problems as well.
Most manufacturers overcome the poor performance in bright lighting by
having a very bright back light on all the time, they dim it for night
usage.

John

Capt John wrote:
Phil,
I've never heard of a transflective touchscreen. A transflector needs
to be mounted on the rear of the displar, not on the front. In the
reflective mode they allow light that has passed through the to be
reflected back out. In the transmissive mode they allow light from a
back light to pass through the transflector. If you mounted it on the
front it would probably make the display harder to read, due to light
losses. It would also probably have lots of glare problems as well.
Most manufacturers overcome the poor performance in bright lighting by
having a very bright back light on all the time, they dim it for night
usage.

John


John,

How about almost _every_ PDA out there? They are all touchscreen as you
will realize, and since the battery cannot afford really bright
backlights they make them reflective.

You're right in that the reflector needs to be on the back, but this
doesn't prevent the manufacturer from fitting a touchscreen on the front.

--
Kees

Kees,
A transflector is a transmissive reflector that is mounted on the back
of an LCD and it can work in two modes.

In the reflective mode light that passes through the front of the LCD
is reflected back out, allowing you to read the display. In the
transmissive mode it allows light from a back light, mounted behind the
LCD, to pass through it and out the LCD, so you can read the display.
If the transflector did not allow light to pass through it from the
back side you would not be able to use a back light, as the light would
never be able to pass through it and out the LCD. Every PDA uses a
transflector like this, and most have a back light that can be turned
on in low light applications.

A touch screen is mounted on the front of the display. It's only
function is for the inputting of data. It must be optically clear so as
to not distort, or dim, the image passing through it from behind.

John

Capt John wrote:

Kees,
A transflector is a transmissive reflector that is mounted on the back
of an LCD and it can work in two modes.

In the reflective mode light that passes through the front of the LCD
is reflected back out, allowing you to read the display. In the
transmissive mode it allows light from a back light, mounted behind the
LCD, to pass through it and out the LCD, so you can read the display.
If the transflector did not allow light to pass through it from the
back side you would not be able to use a back light, as the light would
never be able to pass through it and out the LCD. Every PDA uses a
transflector like this, and most have a back light that can be turned
on in low light applications.

Thanks for the great explanation on something that has had me confused
for a while. I have a Palm Tungsten T3 that has a backlight. It works
very well indoors. As soon as I take it outside it into daylight it
darkens up and becomes pretty much useless. With direct sunlight, you
can't even tell that it is turned on. That must be a different kind of
display. What is that called? I am told that it does not have a light
sensor that turns off the backlight in daylight.

It is a brilliant, sharp, display but disappointing for daylight use.

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com)