Lens systems
Lenses are used almost exclusively for luminaires for point light sources. As a rule the optical system comprises a combination of one reflector with one or more lenses.
Collecting lenses
Collecting lenses direct the light emitted by a light source located in its focal point to a parallel beam of light. Collecting lenses are usually used in luminaire constructions together with a reflector. The reflector directs the overall luminous flux in beam direction, the lens is there to concentrate the light. The distance between the collecting lens and the light source is usually variable, so that the beam angles can be adjusted as required.
Fresnel lenses
Fresnel lenses consist of concentrically aligned ring-shaped lens segments. The optical effect of these lenses is comparable to the effect produced by conventional lenses of corresponding shape or curvature. Fresnel lenses are, however, considerably flatter, lighter and less expensive, which is why they are frequently used in luminaire construction in place of converging lenses. The optical performance of Fresnel lenses is confined by aberration in the regions between the segments; as a rule the rear side of the lenses is structured to mask visible irregularities in the light distribution and to ensure that the beam contours are soft. Luminaires equipped with Fresnel lenses were originally mainly used for stage lighting but are now also used in architectural lighting schemes to allow individual adjustment of beam angles when the distance between luminaires and objects varies.
Sculpture lens
The sculpture lens produces asymmetrical light distribution. It spreads the beam of light in one axis, while leaving the light distribution unchanged on the other axis. The parallel ribbed lens produces a vertical oval when the ribs are orientated horizontally.
Spread lens
The spread lens is used with wallwashers. It produces asymmetrical light distribution. It spreads the beam of light in one axis, while leaving the light distribution unchanged for the other axis. The parallel ribbed lens produces a vertical oval when the ribs are orientated horizontally. This produces very even wallwashing.
Flood lens
The flood lens spreads the beam symmetrically. In addition, this textured lens gives softer transition at the beam edge.
Softec lens
The ability of the Softec lens results in a soft beam. This can be produced via a textured or frosted glass. Softec lenses are used to smooth out visible striations from reflector lamps. As a lamp cover, it prevents dazzle by reducing the lamp luminance.
Projecting systems
Projector with optical system: a uniformly illuminated carrier (1) is focused via a lens system (2). The ellipsoidal projector (left) with high light output, and the condenser projector (right) for high quality definition.
Projecting systems comprise an elliptical reflector or a combination of spherical reflector and condenser to direct light at a carrier, which can be fitted with optical accessories. The light is then projected on the surface to be illuminated by the main lens in the luminaire.
Image size and beam angle can be defined at carrier plane. Simple aperture plates or iris diaphragms can produce variously sized light beams, and contour masks can be used to create different contours on the light beam. With the aid of templates (gobos) it is possible to project logos or images.
In addition, different beam angles or image dimensions can be selected depending on the focal length of the lenses. In contrast to luminaires for Fresnel lenses it is possible to produce light beams with sharp contours; soft contours can be obtained by setting the projector out of focus.
