I think it's a correct sentence. Its intention is to emphasize the verb "invent".

In English We have 2 types of questions 'object' questions and 'subject' questions. Where does he live? is an object question because the question word 'where' refers to the object of a positive statement. He lives in London (London = where ). Object questions are formed with an auxiliary verb in front of the subject. Or in the case of 'to be' by inverting verb and subject. Subject questions are different. They are usually possible with the question words Who, What and Which. Who Invented the TV? is a subject questions because the question word replaces the subject of a positive statement. John Baird invented the TV (John Baird = who) Subject questions are not formed with auxiliary verbs in the present or past so we don't use do, did, and the subject and verb are not inverted. Note you can say 'Who did invent the TV?' when you want to emphasis contrast. Ex 'So, if Marconi didn't invent the TV, who DID invent the TV?' The word 'did' is spoken more emphatically.