Thread: LCD Backlight Upgrade

What is the goal of this project?

Well as everyone knows the backlight on the Lilliput and Xenarc screens are quite inadequate.

So with help from Scouse Monkey and others, we are trying to find a solution that will give us a cheap and easy way to upgrade the backlighting system in our screens without having to pay anywhere from $500 to $1000 for what we feel might be an easy fix.

Not only are we going to be upgrading the brightness we are also working on a auto dimming circuit that will use a phototransistor to adjust the level of brightness without any user intervention.



Current Information on the project.



CCFL Project Percent Completed [#####_____] 50%
CCFL Project Status = Waiting for final designs from china

LED Project Percent Completed [ON HOLD]
LED Project Status = We have put the LED project back on hold, turbocad is currently testing LED's so we will see what he comes up with.



07/27/05 Update

Going back and forth with china again for a 2nd redesign of the CCFL tubes. Hopefully will have 3 or 4 sets of samples within a couple weeks.

Now back on the search for inverters, but as this design uses lower power tubes it should be easier to source the correct inverters.


7/15/05 Update

Well everyone we are still here, due to the issues with finding the correct inverters we are currently revisiting the LED backlight modules



7/12/05 Update

just a little status update, we are still here and still working away at this project. It's just been really hard to find the parts we need at a decent price.

I did find something interesting in my testing tonight though, you can use a Panasonic screen on a lilliput controller! Which is awesome news now I can test both types of screens on the same controller.


5/27/05 Update

The backlight control is coming along nicely. I almost have the code finished, next comes the actual circuit.

We have started a thread to document this process as well
LCD Backlight Upgrade Autodimming control




5/23/05 Update

Just wanted to give everyone a status update, i'm still here, I just dont have any working controllers at this point to test with. So i'm just waiting to hear back from DigitalWW. I am also waiting to hear back from ERG about purchasing the inverters we need.



5/19/05 Update

Well after blowing out my last test controller, the hunt is out for a replacement.

After contacting ERG about inverters, looks like they have a unit that will do the job nicely. So hopefully I can purchase a few and get back to testing


5/11/05 Update

Well after testing with good results, now the search is out to find better inverters. Next up is going to be the heat test where we will find out if the display can handle the extra heat for a extended period of time.

more pictures on posts 166 and 167!


5/10/05 Update

The tubes are in!! see posts 77 and 94 for pictures!


5/8/05 Update

The CCFL tubes and the Inverters have shipped from china!

So they are in-transit, which means I should have them by mid week.

I also received the ultrabright white LED's today for testing.



5/7/05 Update!

I received a e-mail from china, they are finishing up the quality control testing of the tubes. So they should be on time for shipping on Monday the 9th.

Information website is up!

i'm going to be posting all of the test result images as well as guides to taking your screen apart there

http://www.jcdsystems.net/ccfl.html




4/29/05 Update

Due to the holiday in china the tubes will not ship until the 9th of May



We currently have 2 different sizes of tubes coming; we have a 2.6MM tube and a 4.1MM tube.

We are currently working on a circuit that will provide automatic dimming for the CCFL's. So at night no adjustment would be needed.

The brightness upgrade will have new a new inverter so the built-in inverter that is currently in the screens will not be used.








Project FAQ



OMG How are you going to control the brightness for night use?

We will have a couple diffrent options for dimming

1. Photocell mounted aound the screen bezel (will recomend people look at their dash in sunlight and mount it in the spot where most light falls on the screen).

2. Manual pot to turn up/down the autodimmed levels - ie the screen will still auto adjust but if it's not quite right you can alter it.

3. manual mode to prevent any auto adjsuting

4.-OPTIONAL-PC control so the frontend can increase the brightness for some apps or you can build a nice OSD fo control the autodimming if you dont want to have buttons.

5. The manual adjustment might be done with 3 buttons. ie one for up, one for down and one to toggle auto on or off.


What screens is this being developed for?

Well right now we are shooting for the two main types of screens.

7" Lilliput which contains a Hitachi LCD panel.
7" Xenarc which contains a Panasonic LCD panel.

If this design works we will move on to the bigger style screens.


What are you using to do the upgrade?

We have been going back and forth between CCFL backlights and LED based backlights. For right now we have settled on CCFL tubes for our backlighting project. Because of their price and ease of use.


What will this be replacing and will it require alot of changes to my screen?

What were are trying to end up with is that you will be removing the stock CCFL and the stock light guide and just putting the new tubes into the stock LCD housing. So the only thing you should have to do is cut a few small holes in the side of the LCD for the 2 extra tube ends to come out.


How bright is this going to be?

Well everything right now is a guess, but we are hoping for the 800 to 1000nit range. Untill we get the tubes and test them we really dont know.


How much will it cost?

The final cost is unknown at this time but we are aiming to keep it under the $100 mark.



Will this be a kit or will you be offering to do the upgrade?

Well after we test the solution, it should be available as a kit. But later on down the road we might go for installing the kit for people.



I'd like to make a donation. Who should I send it to?

Just go to this address and use the donation button located there.

http://www.jcdsystems.net/ccfl.html

A special thanks goes out to all that have donated, you have made this much easier on me

all listed in no particular order

Quattro
old_lou
tj!2k4
MaleBuffy
migel628
04scooby
sonex293
Blue ZX3
JC-S60
NUIpIsqo

if I forgot to list you i'm sorry!




Where can I find information about the history of this project?

This is the timeline for the project

4/12/05 Project Started
4/15/05 Contacted company in China that produces custom CCFL Lamps
4/22/05 Design sorted out with company in China, Payment sent for set 6 sample tubes.


The original thread started here.
So, give us new LCD touchscreen options!