Re: TI-H: Backlight

To: ti-hardware@lists.ticalc.org
Subject: Re: TI-H: Backlight
From: "Richard Piotter" <richfiles1@hotmail.com>
Date: Tue, 25 Nov 1997 14:13:07 PST
Reply-To: ti-hardware@lists.ticalc.org
I may be able to do the backlight with different materials and GREATLY 
reduce that dimming problem, FOR CHEAPER!!!

I'll post soon!

It takes alot of work and patience though.

>
>What if we just use green LEDs?  I don't want to take credit for 
someone
>else's idea, because I saw it somewhere else on the web, but three 
LED's
>positioned around the screen can do the trick.  Just add resistors, and
>you've got it.
>    Only problem is diffusion.  The light would get weaker near the 
middle
>of the screen, but maybe that can be dealt with.
>
>Its cheap, and it doesn't use much power.
>
>
>-----Original Message-----
>From: Gregory Whitmore <gfw9941@usl.edu>
>To: ti-hardware@lists.ticalc.org <ti-hardware@lists.ticalc.org>
>Date: Monday, November 24, 1997 7:43 PM
>Subject: Re: TI-H: Backlight
>
>
>>I have found a better way to do the backlight. The only problem is it
>>costs $95.00 and it HAS to have an external power supply. It has to
>>because it needs an inverter to use DC power. I forget the name of the
>>company right now, when I remember I will post. To install the thing 
is
>>really simple though. You just pull the gray "mirror" from your screen
>>and put place this screen behind your LCD. It sticks using that static
>>kinda thing.
>>
>>Gregory
>>
>>
>>
>>
>>Richard Piotter wrote:
>>>
>>> Hi!
>>>
>>> I want to post it, but time and work have prevented me from even
>>> updating the battery expander page. I took a Sharp LM64P something
>>> backlit monochrome LCD apart. It is 640x480 pixsels, and the
>>> diffratction panel is really good. Lights the whole screen if cut 
right!
>>> I don't guarantee your screen will work WELL with it, but I do 
guarantee
>>> it will light it up. The screen lights fine. The problem comes in 
with
>>> some newer screens (maybe it's newer screens, but I'm not sure). The
>>> problem is that to properly install the backlight, you need to cut 
the
>>> rubber that holds the screen off and then peel the mirror off. You 
put
>>> the mirror on the back (rough) side of the difractor and put a 
diffuser
>>> on top, then the LCD. The problem is that some screens use the 
mirror
>>> and polarizer at a different angle, and it isn't compatible with the
>>> diffuser. It dimms the pixels and darkens the background. It isn't 
bad
>>> on some calcs, but it gets fairly annoying on others. Austin butler 
had
>>> a "dim" calc, but he got it and said it took a while to get used to, 
but
>>> that it wasn't too bad. All I can say is you can try. The problem is 
it
>>> it is a dim one and you decide not to do it, it is nearly impossible 
to
>>> put the mirror back on without looking VERY strange. It will have 
air
>>> bubles and dust, no mater how you replace it. If you like you can 
try
>>> with just the corner, but my experience shows that if the mirror is 
a
>>> piece of thick plastic and the one that doesn't work as well (It 
works,
>>> just dimmer pixels when the light is off) is a very flexible piece 
of
>>> plastic foil. You'll know by pulling the corner off. If it is thick, 
go
>>> for it. if it is thin, you may want to think about it. Try it if you 
get
>>> a panel. I charge $40 for the whole job (it has to cover the cost of 
the
>>> LCD panel I took apart). I got it from ALL electronics, but they
>>> nolonger sell it, so it is kindof my last priority. I have enough 
for 4
>>> calcs, and will need 2 or three for myself, so you, austin, and I 
could
>>> end up being the only person with these backlights unless someone 
had
>>> the misfortune of ordering the wrong LCD or thinking they could use 
it,
>>> but couldn't. I was on an LCD list before, so maybe I can purchase 
some.
>>> It would be best to find a black ON white backlit screen. It would 
look
>>> better, but I havn't found one yet.
>>>
>>> If you want it done, I can do it for you. I could send the piece 
(fit it
>>> to my 82 first) but It is difficult and requires patience. I have 
taken
>>> over half an hour just cutting the screen off, cause you obviously 
can't
>>> crack it, and you can't cut those plastic ribbon wires. Tell me what 
you
>>> want to do. I'll do my TI-82 before I do your TI-82, just to see if 
it
>>> works well!
>>>
>>> Respond soon!
>>>
>>> Richard Piotter
>>>
>>> E-Mail:
>>> richfiles1@hotmail.com
>>> richfiles@usa.net
>>>
>>> The Richfiles:
>>> <A
>>>
>HREF="http://www.geocities.com/SiliconValley/Lakes/5081/Richfiles.html">The
>>> Richfiles TI Page</A>
>>> <A 
HREF="http://www.geocities.com/Area51/Lair/8510/Richfiles.html">The
>>> Richfiles Model Building Page</A>
>>>
>>> ______________________________________________________
>>> Get Your Private, Free Email at http://www.hotmail.com
>>
>
>


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