| 359 / | HD | OPTICS: SYSTEMS (INCLUDING COMMUNICATION) AND ELEMENTS |
| 618 | DF | SINGLE CHANNEL SIMULTANEOUSLY TO OR FROM PLURAL CHANNELS (E.G., LIGHT DIVIDING, COMBINING, OR PLURAL IMAGE FORMING, ETC.) {3} |
| 629 | DF | .~ By partial reflection at beam splitting or combining surface {6} |
| 630 | DF | .~.~ Superimposing visual information on observer's field of view (e.g., head-up arrangement, etc.) {3} |
| 632 | | .~.~.~ Rotatable heads-up device or combiner |