Yasuo Iwakura 岩倉 康雄 (Iwakura Yasuo)
Lain's father is a computer enthusiast with a room full of monitors, and he is delighted when his quiet daughter finally asks for a proper NAVI. He orders a powerful model, sets it up for her and lectures her that the Wired is a communication tool that should not be confused with the real world. His warmth always carries a faint distance, as if he were taking notes on her progress, and he reacts coldly when she shows him the Psyche chip. Konaka has said Yasuo's character was not fixed at the start and took shape strangely, day by day, as the scripts were written. In a 2018 4Gamer talk Konaka said the many monitors in Yasuo's room were his own wish. Ryusuke Obayashi (credited as Ryunosuke Obayashi) voices him; his laugh is famously odd.
More (spoilers)
In Layer 10 Lain comes home to an empty house. Yasuo appears only to say goodbye: their 'job' is over, he was never really her father, he did not enjoy pretending to be a family but envied a being like her, and he still loved her. Ueda said at Otakon 2000 that the family were placed to collect information and report to someone, left for viewers to decide. After the reset Yasuo is the one who seems to sense Lain, and in Layer 13 he sits with her and offers tea and madeleines.
Sources: en.wikipedia.org archived · ja.wikipedia.org archived · animenewsnetwork.com archived · konaka.com archived · 4gamer.net archived · lawmune.net · lain.wiki