Lighting devices or systems producing a varying lighting effect

F21S 10/00

Optical projection comparators

G01B 9/08

Apparatus for optical projection, in general

G02B 27/18

Viewers, other than projection viewers, giving motion-picture effects by persistence of vision, e.g. zoetrope

G03B 25/00

Photographic printing apparatus

G03B 27/00

Television systems' projection arrangements for image reproduction

H04N 5/74