That’s a pretty strange controller patent…check out some information concerning that space in the middle…
An X button 46 and a Y button are further arranged in line on the upper surface of the housing. An imaging information arithmetic unit is provided at a front end of the housing in a longitudinal direction in such a manner that an imaging device thereof is exposed from a front-end surface.
Check out the full patent here, if you feel like snooping through endless amounts of text. Thanks to KingBroly for the heads up!