In 1928, the American D.B Gardner registered a patent application concerning the restitution of a television image using a series of mirrors laid out in a helicoid way, around an axis.
Set of mirrors
This process is put into practice between 1930 and 1935 by some companies like BELL Laboratories in USA and TEKADE in Germany. Practically at the same time, in Europe, the Hungarian Frantz Von OKOLICKSANYI discovers a similar process. Around 1932, the french Joseph BRAMI build a miniaturized apparatus with 30 mirrors which holds in the hand, the VISIOLA (french archive.)
The Gardner mirror screw television system present significant advantages compared to the Nipkow scanning disc. First of all, the image size that can be obtained with the Gardner system is much larger than with a Nipkow disc. The brightness is also considerably more important and several people can see the images at the same time, which is not possible with the Nipkow system.
Also, the Gardner system presents particularities such as: according to the distance where you are from the mirrors, you will see one or more images side by side. Thus, the position of the observer is critical and he will see the image being duplicated if he is not at the good distance. Refering to the light module which illuminate the mirrors, its position is also critical. It must consequently be calculated precisely in order to avoid unfoldings and/or luminosity troubles on the images.
Links to get more informations on past and actual experiments on Gardner mirror screw (coloured images )
Early Television Foundation and the web site of Peter Yanczer.