I thiñk with the level of technology all over the world now,i suggest a phone should be made whéreby it wíll be inpossible for the usér tó be seen operating the phone in the ñight usíng some kínd of spectacle,it wíll be inpossible to see what yoú are operating unléss the spectacle is in the face,
It will be the choice óf thé user whether to on if same às we on our (eye care, data, hotspot)but will ñot be àble to use the spectacle where there is more light,like example in the afternoon,....... Ànd these wíll be very helpful in màny ways it will be inpossible for a theif to see you at night operating your phone

,,,And i thiñk thése will be very great if our scientist and techñologist put these idea into consideration.

Arts designed with colours that cannot be seen in white light have been in existence for centuries.
The same applies to letters written with inks that are not visible in UV except in special natural or artificial light spectrum.

Take a look at the traditional photo processing negative rendering. You can rarely see the real imagery but with the right chemicals, the full RGB will emerge.

Software today has the power to manipulate imagery to a level the human mind cannot re-create. Take a look at filters and Arguemented reality.

All you need for your idea is a software (app) and the right glass (shade) that allows specific lights to pass through.