Dry Ice Is Nice For Separating Broken Phone Screens

Smartphones are the opium of the people. If you need proof, just watch the average person’s reaction when they break “their precious”. Repairing smartphones has become a huge business. The most often broken item on phones is of course the front glass. In most cases, the screen itself doesn’t break. On newer smartphones, even the touchscreen is safe. The front glass is only a protective lens.

The easiest way to repair a broken front glass is to swap the entire LCD assembly. For an iPhone 6 plus, this will run upwards of $120 USD. However, the glass lens alone is just $10. The problem is that the LCD, digitizer and front glass are a laminated package. Removing them without breaking the wafer thin LCD glass requires great care. The hardest part is breaking down the optical glue securing the glass to the LCD. In the past that has been done with heat. More recently, companies from China have been selling liquid-nitrogen-based machines that cool the assembly. Now immersing a phone screen in -196° C liquid nitrogen would probably destroy the LCD. However, these machines use a temperature controller to keep a surface at -140° C. Just enough to cause the glue to become brittle, but not kill the LCD.

[JerryRigEverything] doesn’t have several thousand dollars for a liquid nitrogen machine, but he does have a $5 block of dry ice. Dry ice runs at -78.5°C. Balmy compared to liquid nitrogen, but still plenty cold. After laying the phone screens down on the ice for a few minutes, [Jerry] was able to chip away the glass. It definitely takes more work than the nitrogen method. Still, if you’re not opening your own phone repair shop, we think this is the way to go.

Broken phones are a cheap and easy way to get high-resolution LCD screens for your projects. The problem is driving them. [Twl] has an awesome project on Hackaday.io for driving phone screens using an FPGA. We haven’t seen it done with iPhone 6 yet though. Anyone up for the challenge?

29 thoughts on “Dry Ice Is Nice For Separating Broken Phone Screens

    1. Might. I was removing some security tag labels off some products we were returning back to the distributor and they have some gnarly adhesives that often damage the boxes. Some plasticoated paper can’t handle a heatgun, turned a can of air duster upside down on it and it popped right off.

  1. I had to do the same on my phone, but the opposite way, with heat. I used the hotbed on my printer to soften the glue and carefully scrape the pieces off with a playing card. Too much heat damages the LDC too, so the regulated hotbed was chosen over the heat gun method. Took forever.

    1. That is a good idea using the hotbed.

      My phones screen broke down to little pieces when it dropped. I used a heat gun. I shielded the part that did not have glass anymore with some piece of plastic when i heated the parts that had glass. It took 2-3 hours to chip away the little pieces off of it. I have another phone screen replacement project coming up. I’ll try it with the hotbed.

  2. Hm… can someone provide a relevant link (?)– What exactly is ‘optical glue’ ? Of course the concept of what it does is pretty obvious, but does this refer more to the chemical makeup, or simply method of application, etc. Am interested.

    1. They are typically one part UV or oven curable optical epoxies. Similar to Epotek 310 series material.
      Because they are thermoplastics (when cured), they can be softened with heat, and become more brittle with low temperature. Really low temperature cause surface sheer de-bonding from the substrate due to their relatively high thermal expansion coefficient.

  3. We had a cold machine for 2 months and it’s terrible. If it’s a genuine screen it works about 70% of the time if it’s refurbished it doesn’t work and kills the lcd as the oca laminate doesn’t separate like the loca that Apple use. In the end we went back to heat and wire and replace the polorisor which is 90% efficient. Cold is just a gimmic and we wasted $10,000 on it.

  4. And sometimes it kills it all. My Galaxy S4 tri-band did a faceplant onto a tile floor. Broken glass, destroyed digitizer and display. Can hardly tell there’s any damage, can only see the cracks by looking across the glass at a low angle.

    It could still receive calls thanks to the physical Home button, but that’s all it could do.

    Fortunately I’d had USB debugging enabled so I was able to use the Vysor addon for Google Chrome to have a virtual phone display with mouse pointer control on my desktop computer. I was able to backup everything to the SD card.

    Then I bought a used non-tri-band S4. It gets better LTE reception, so it works in some places that were dead spots for the tri-band. I’m thinking about getting a media dock to plonk the broken one onto, to use with a Logitech K400 and a large USB stick as a media center connected to my HDTV. Won’t need the phone’s display or digitizer for that.

  5. I separated LCD and glass using the heat gun and a thermometer, that worked fine. Unfortunately I couldn’t get the LOCA to cure properly and without bubbles so I resorted to swapping the display assembly after buying and breaking the glass 3 times.

    1. I was able to get it to cure without bubbles, but it developed lines/wrinkles across the screen afterwards. Possibly didn’t get enough UV exposure to cure properly.The technique I saw was to make a streched x-shape pattern like ‘>-<' on the screen with the glue and set the glass on perfectly flat, and let its own weight spread the glue (be patient, don't press). As it slowly spreads the edges intersect at a shallow angle and don't trap bubbles.

  6. Using dry ice to separate a screen is an interesting alternative to the expensive machines, for sure. Maybe this could lead to further solutions that bring down the costs associated of screen repair.

  7. I had no idea that dry ice could separate the screen from the phone. I just shattered the screen on my phone and pieces of glass come off whenever I use it. I think this time I will have to go to a repair shop to help fix the screen. I will definitely keep the dry ice idea in mind for future references. Thanks for the information!

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