Profile spotlights
Profile spotlights can bring about the focusing of a projection area by using a double lens system. The demarcation to the dark areas is precise and exact.
There are profile spotlights with manual and automatic focus on the market. Versions with automatic focus usually also have color wheels or gobo wheels for projecting patterns and figures with sharp delineations.
The further development of simple profile spotlights are scanners and moving heads .
Details
Basically a profile spotlight is a projection device and has the same optical structure as any slide projector , film projector or video projector . It consists of (in the order from the emergence of the light to the exit from the device):
- Light source
- Condenser system
- Carrier for the projection object
- Projection lens
Mechanically, the profile spotlight is essentially made up of a lamp housing with illuminant and condenser optics as well as the tube with object carrier and projection lens. The latter can be designed with a fixed focal length (only one lens, movable) or with a variable focal length (two lenses, movable to each other and to the object - zoom lens ).
The object carrier contains the recordings for the four shutter plates (to limit the light cone), as a rule for an iris diaphragm and, with higher-quality devices, also for so-called gobos (projection templates punched or cut in sheet metal). In principle, slides or templates painted on glass could also be used here; however, the quality of the projection will mostly be inadequate.
use
The profile spotlight is used
- to generate a sharply defined cone of light
- to limit the light cone with sharp edges
- for the projection of a graphic object
- for illuminating from a greater distance while avoiding scattered light
- in a special design as a chase spotlight
The light distribution within the light cone is fairly uniform without a clear focus, which is why the light quality can appear a bit flat depending on the application. For this reason, it is not recommended to use it for purposes other than those mentioned above.