Advice on making a liquid crystal screen (shutter)

In summary: Wax paper is good because it doesn't adhere to the glass, but if it gets covered in liquid crystals it will be hard to remove.
  • #1
wosoka
44
2
I need to make my own smart film for some experiments.

I've read enough articles on it to know the required components, how they are mixed and applied.

I have a 1:1 mixture of liquid crystal and UV curable resin and glass bead spacers that I need to apply between two ITO PETs and UV cure to bond all the layers together. Glass spacers are used to get unform thickness which is needed for uniform opacity/transparency.
This will create a "smart film".

This is probably done industrially by precision rollers and very powerful UV light to cure it immediately as it leaves the rollers, but I don't have access to such equipment.
Any ideas what else I can try?

If I squeeze the layers and release before UV curing I fear the thickness of the liquid crystal layer will increase back a little. So I probably need pressure applied while the UV glue inside the mixture is being cured by UV light.

I could squeeze the layers with a thick glass slab and use powerful UV LEDs to cure the liquid layer, but I fear the liquid leaked from the sides may adhere the glass slab to it. That could still be removed with an exacto knife but it may easily adhere to the baseplate as well, leaving it stuck between the two.

If I apply some powder or oil which will prevent adhesion to the glass slab and/or baseplate, it may affect the flat surface of the slabs required to cause the spacers inside the mixture to create a uniform 20 micron thickness across the sheet, as the outer layers of the "smart film" are plastic (PET) and not rigid glass. But I may be wrong on this, just an assumption.

Another option may be using some rigid material for a baseplate which doesn't get glue (UV curable resin) adhered to it. I am not aware of such material.

I've already tried without glass spacers and perfect layer thickness and just hand squeezing but the fading speed and opacity is not uniform across the sheet which is a requirement for my experiments.

Any ideas?
 
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  • #2
I'm not understanding your assembly process yet. It sounds like you are using an IR UV cure to seal the LCD sandwich together? Does that seal just the edges, or does it somehow cure the whole LCD mixture? It's been a while since I worked with LCDs, but I'm more used to edge seals and a liquid in the middle of the panel with the spacers...

http://www.liquidcrystaltechnologies.com/images/LCDCross.gif
LCDCross.gif


EDIT -- Fixed IR cure --> UV cure in my post above.
 

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  • #3
wosoka said:
but I fear the liquid leaked from the sides may adhere the glass slab to it.
Use a "slip sheet" between your work and the glass slab. I have often used a sheet of ordinary household Wax Paper. It is readily available in grocery stores here in the USA at least.
 
  • #4
Tom.G said:
Use a "slip sheet" between your work and the glass slab. I have often used a sheet of ordinary household Wax Paper. It is readily available in grocery stores here in the USA at least.
Sounds like that will work.
 

Related to Advice on making a liquid crystal screen (shutter)

1. What materials are needed to make a liquid crystal screen?

To make a liquid crystal screen, you will need a glass substrate, transparent electrodes, polarizing filters, a liquid crystal solution, and a backlight.

2. How do I assemble the liquid crystal screen?

First, place the transparent electrodes onto the glass substrate. Then, sandwich the polarizing filters on either side of the electrodes. Next, add the liquid crystal solution between the filters. Finally, add the backlight behind the substrate.

3. What type of liquid crystal solution should I use?

The type of liquid crystal solution used will depend on the specific application and desired properties of the screen. Common types include twisted nematic (TN), in-plane switching (IPS), and vertical alignment (VA).

4. How do I control the liquid crystals to create images on the screen?

To control the liquid crystals, an electric field is applied to the transparent electrodes. This changes the alignment of the crystals and allows light to pass through, creating images on the screen.

5. Are there any safety precautions I should take when making a liquid crystal screen?

Yes, it is important to handle the liquid crystal solution with caution as it can be toxic if ingested or inhaled. It is also recommended to wear gloves and protective eyewear during assembly to avoid contact with the solution.

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