Juishan Hsu and her daughter just filed docs against Princess Cruise Lines, claiming the company exposed passengers aboard the Ruby Princess to the novel coronavirus ... which eventually killed her husband, Chung Chen.

According to new legal docs, obtained by TMZ, Juishan says she and her husband set sail out of Sydney on March 8. She claims PCL was aware of a COVID-19 outbreak on the ship, but proceeded with the cruise without warning passengers.

Juishan claims they would not have boarded if they knew about the outbreak, and would have immediately taken the first flight home. In the docs, she and her daughter claim PCL still sent out ships after 3 major outbreaks on its cruises, including one a week before on the Ruby Princess.

Princess Cruise Lines only took minimal precautions, according to the suit, including delaying boarding for the Ruby Princess by 6 hours and handing out lunch vouchers to passengers while crews tried to disinfect the ship.

But, the family claims the cruise line failed to quarantine onboard and didn't even notify passengers of the outbreak, "allowing the sailing to continue as if it were a normal cruise"

Juishan says her husband died April 4 from COVID-19 complications. She's going after the cruise line for more than $1 million in damages.