| 摘要 |
An apparatus is disclosed for projecting patterned electromagnetic waves onto an object. This apparatus includes: an electromagnetic-wave source; a modulating element allowing at least part of an electromagnetic wave incoming from the source to be modulated; and a selector for allowing a selected one of angular components of an electromagnetic wave outgoing from the modulating element, to pass through the selector. The modulating element is shaped to include at least one pair of two portions having different surface shapes. One of the two portions allows one of the angular components which has a radiant angle characteristic that achieves a predetermined entrance numerical aperture, to go out as a component which will be selected by the selector. The other allows one of the angular components which has a radiant angle characteristic that does not achieve the entrance numerical aperture, to go out as a component which will not be selected by the selector.
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