Hello all,

Today I took apart my brand new 22” LCD screen to use for my MT table, and I’m happy to say that after disassembling it, it still works.

Unfortunately, there are two issues with the screen as it is now, and I was hoping maybe some of the more seasoned LCD users on the forums could point me in the right direction..

First of all; the honeycomb structure. It’s embedded in the layer that floods the backlight out evenly, and it’s visible because I had to take the layer above it out because it blocked almost all my IR light. Is there anything I can do about this or am I just going to have to live with the honeycombs? I’ve thought about taking that layer out as well, but it will mess up the backlight considerably.

Second problem, and this one is pretty bad; the backlight seems to give off a tremendous amount of IR light. The whole screen just shows up as a big white rectangle and I can’t read anything that’s on the other side. Is there something I can do here, or do I have to start thinking about building my own backlight?

Any input would be highly appreciated, I really want to get this to work!

Emiel - 16 July 2008 04:59 PM

Hello all,

Today I took apart my brand new 22” LCD screen to use for my MT table, and I’m happy to say that after disassembling it, it still works.

Unfortunately, there are two issues with the screen as it is now, and I was hoping maybe some of the more seasoned LCD users on the forums could point me in the right direction..

First of all; the honeycomb structure. It’s embedded in the layer that floods the backlight out evenly, and it’s visible because I had to take the layer above it out because it blocked almost all my IR light. Is there anything I can do about this or am I just going to have to live with the honeycombs? I’ve thought about taking that layer out as well, but it will mess up the backlight considerably.

Second problem, and this one is pretty bad; the backlight seems to give off a tremendous amount of IR light. The whole screen just shows up as a big white rectangle and I can’t read anything that’s on the other side. Is there something I can do here, or do I have to start thinking about building my own backlight?

Any input would be highly appreciated, I really want to get this to work!

HoneyComb: You need to leave the honeycomb layer in there, as you have already noticed this is going to spread or diffuse the backlight well. And yes the layer you took out between honeycomb and LCD is usually what you would expect, instead you can add a nice thin translucent vellum in between. This will give you almost as good of a backlight as its original form and won’t hinder any “blobbage”.

Second, about the IR from backlight, well in my case the LCD backlights did not give off any IR at all. Are you sure your camera is modded and you have taken out the background with threshold and all those settings? Typically backlights (FL) are not suppose to emitt IR. They are clean bright bluish white light. In any case you can get some IR blocking films from some hardware store, they sell this stuff in Windows Section. I never had to use one but someone recommended it before.

Hope this helps.

By the way are you using some Dell Monitor? Your LCD circuitry and form looks almost exactly similiar to mine.

I would be careful with the IR film.  I don’t know how hot those back lights get, but if you are going to be applying it right on it might melt.  Just a though, not sure how accurate it is.

GeoMan - 17 July 2008 03:32 PM

HoneyComb: You need to leave the honeycomb layer in there, as you have already noticed this is going to spread or diffuse the backlight well. And yes the layer you took out between honeycomb and LCD is usually what you would expect, instead you can add a nice thin translucent vellum in between. This will give you almost as good of a backlight as its original form and won’t hinder any “blobbage”.

Second, about the IR from backlight, well in my case the LCD backlights did not give off any IR at all. Are you sure your camera is modded and you have taken out the background with threshold and all those settings? Typically backlights (FL) are not suppose to emitt IR. They are clean bright bluish white light. In any case you can get some IR blocking films from some hardware store, they sell this stuff in Windows Section. I never had to use one but someone recommended it before.

Hope this helps.

By the way are you using some Dell Monitor? Your LCD circuitry and form looks almost exactly similiar to mine.

Hi GeoMan, thanks for the reply. I’m using an xbox live camera with the filter removed and 2 layers of exposed photo negative inserted, so that should work; I haven’t had any problems in my previous tests without the screen. The backlight is bluish white, just like you described. I’ll see if I can upload some screen soons of what it looks like in TouchLIB later today. And to be completely honest.. I’m pretty new to TouchLIB so I’m not sure if my settings are correct, I could really use some help on that. :D

I’m using a BenQ screen, but I can imagine that there’s not much variation as far as circuitry goes.

xelapond - 17 July 2008 04:19 PM

I would be careful with the IR film.  I don’t know how hot those back lights get, but if you are going to be applying it right on it might melt.  Just a though, not sure how accurate it is.

Hi xelapond,

Yeah, my backlight does get pretty hot. :/ Someone suggested the window film on my blog as well, and even though I was enthusiastic at first, I reached the same conclusion; probably not a good idea.

Hello again,

Back with some more info; the caulk paper worked like a charm! The honeycomb pattern has vanished and the screen still lets through plenty of IR.

As far as the screen emitting IR goes… that’s still confusing me. With the proper settings I was able to eliminate most of it, but I wonder if it’ll work once I have the screen mounted and I’m trying to get blobs off my lasers. The screen just shows up like a massive brick of IR light! Please have a look at the attached picture and see if I’m wrong about this.