All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
What you have understood that touching a mobile phone that has a Quran application does not need from the person to be in a state of purity is correct because it is not considered a Mushaf (the Arabic text of the Quran).
Shaikh Abdulrahman bin Naser Albarrak said:
“It appears that the mobile phone and other devices in which the Quran is recorded do not have the same ruling as the Mushaf. Because the existence of the letters of the Quran in these devices is different from that on the Mushaf as they are not in a readable form (capacity).
Rather, they are in the form of vibrations and symbols from which the letters are formed as they are when required, so they appear on the screen and disappear when moving to other things or applications.
Therefore, it is permissible to touch the mobile, the tape in which the Quran is recorded, and to recite the Quran from a mobile phone without purity. This is the established opinion in my view.” [End of quote]
As for opening the Quran application and displaying the Quran through an impure or unclean screen, then there is no doubt that this is against the exaltation that should be given to this Book as ordained by Allah, The Almighty. How could a Muslim accept displaying the verses of the Quran in front of him while they are covered by dirty or impure things?
So, in our view this is impermissible. Furthermore, if the intention is to mock or belittle the verses of the Quran, then the prohibition is very clear, and it reaches Kufr (disbelief), may Allah forbid.
Allah knows best.