The 1964-65 New York World's Fair had lighting fixtures ("luminaires") that used a special flat panel fluorescent lamp:
http://www.lamptech.co.uk/Spec%20She...0Panel%20F.htm
Manufacture of these panels was discontinued after a few years partly because of poor lifetime due to problems in sealing them thoroughly during manufacture.
Here are some pictures of the luminaires:
https://www.worldsfairphotos.com/nywf64/luminaires.htm