Diffuser to be detachably mounted on a reflector screen or the like

A diffuser for releasable fastening to a reflector screen having screen spokes, includes a diffuser element and a fastening apparatus to fasten the diffuser element to the reflector screen. The fastening apparatus has a plurality of fastening elements constructed and adapted to receive corresponding screen spokes of the reflector screen. The fastening elements are constructed to apply a spring action and each fastening element has an opening to receive one screen spoke.

This application is a 35 U.S.C. §371 filing of International Patent Application No. PCT/EP2008/005436 filed Jun. 25, 2008, designating the United States and claiming the benefit of German Application No. 20 2007 009 232.6 filed Jun. 28, 2007.

BACKGROUND OF THE INVENTION

The invention concerns a diffuser for releasable fastening to a reflector screen or the like, comprising a diffuser element as well as fastening means for fastening the diffuser element to the reflector screen or the like.

Diffusers of this kind are used in particular in the field of photography or film, preferably in connection with a reflector screen or the like. By means of the reflector screens, preferably different light and/or shadow effects and images are produced or formed. The diffusers, which are arranged in the region of a light outlet opening of the reflector screen, are used in particular to scatter light. A diffuser obtains the result, for example, that the transitions between light and shadow are altered. In particular, the transition from light to shadow and vice versa becomes more blurred. In this connection, so-called soft light is also spoken of. Furthermore, disturbing sheens such as occur on smooth surfaces, for example, can also be reduced with diffusers.

The diffusers are releasably fastened to the reflector screens. To vary the diffuser effect, the diffusers can be exchanged. The diffusers are removable for folding the reflector screens as well. Diffusers which have hook-and-pile fasteners, studs or the like as the fastening means are known. Specifically, the diffuser elements are laid over the light outlet opening of the reflector screen and, using the fastening means, connected thereto in snug-fitting relationship. However, the previous diffusers have the drawback that firstly they virtually close the light outlet opening, which leads to heat accumulation within the reflector screen when the lamp is switched on. Secondly, the known diffusers crease due to lack of tension, leading to uneven or irregular illumination.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to provide an easy-to-handle diffuser which avoids the above drawbacks.

This object is achieved by a diffuser of the kind mentioned hereinbefore by the fact that the fastening means has several fastening elements constructed and designed for receiving corresponding screen spokes of the reflector screen. Usually, these screen spokes project beyond the light outlet opening of the reflector screen. As a result it is possible to position the diffuser element at a distance in front of the light outlet opening of the reflector screen, so that the heat generated by the or each lamp can circulate. The service life and durability in particular of the reflector screens and associated lamps can therefore be greatly improved.

Preferably, several plate-like fastening elements are evenly distributed over the circumference of the diffuser element and fastened thereto. By this means, uniform fastening or “suspension” on the screen spokes is guaranteed in an effective manner, leading to crease-free tensioning of the diffuser element.

An appropriate development provides that each fastening element is designed as a tensioning element. This assists reliable mounting of the diffuser on the reflector screen without creasing.

Advantageously, each fastening element is designed as a single-piece element which applies a spring action, so that uniform tension can easily be applied to the diffuser element.

A preferred embodiment is distinguished in that the fastening elements are preferably rectangular plates, the plates having an opening for receiving one screen spoke each. As a result, the diffuser is made particularly easy to handle, that is, in particular when mounting it on the reflector screen and removing it.

Preferably, the opening is arranged eccentrically in relation to the centre M of the fastening element. As a result, a leverage which assists the spring action is defined, such that the diffuser element is tensioned virtually in cantilever relationship without direct contact with the reflector screen.

BRIEF DESCRIPTION OF THE EMBODIMENTS

The diffuser described below is particularly suitable for mounting on a reflector screen or the like. Naturally, the diffuser can also be used elsewhere, e.g. with lightning equipment, etc.

For a better understanding of the invention, first an arrangement10consisting of a reflector screen11and a diffuser12is described with reference toFIG. 1. The structure of the reflector screen11can vary. Purely by way of example, the reflector screen11, which can be openable or rigid, has a reflection element13, a supporting and tensioning structure14and a carrier element15having at least one lamp16. The supporting and tensioning structure14comprises screen spokes17and expanding spokes18. The screen spokes17are inserted in external seams of the reflection element13and extend from a bearing body19into the region of a light outlet opening20of the reflector screen11. The screen spokes17, which are evenly distributed over the circumference of the light outlet opening20, project beyond the light outlet opening20. Optionally, the screen spokes17can be provided at the free end with an e.g. spherical closure cap21or the like. In other embodiments not shown, the construction of the reflector screen11can be completely different. It is crucial that in the region of the light outlet opening20a fastening means, which in the embodiment shown is formed by the projecting screen spokes17with the spherical closure caps21, projects beyond the light outlet opening20.

The diffuser12for releasable fastening to the reflector screen11or the like comprises a diffuser element22and fastening means23for fastening the diffuser element22to the reflector screen11. The fastening means23has several fastening elements24which correspond to the fastening means of the reflector screen11. In particular, the fastening elements24are constructed and designed for receiving one screen spoke17each of the reflector screen11. The plate-like fastening elements24are evenly distributed over the circumference of the diffuser element22and fastened thereto. For fastening, various common options are possible. Particularly preferably, the fastening elements24are stitched to the diffuser element22, which can be made of e.g. films, glass fibres, textile fibres or combinations thereof and other materials.

The number of fastening elements24can vary, but preferably corresponds to the number of corresponding screen spokes17of the associated reflector screen11. Each fastening element24is designed as a tensioning element. This can be achieved firstly by separate tensioning mechanisms. But preferably the fastening elements24are “inherently” tensionable by a suitable choice of materials. In other words, each fastening element24is designed as a single-piece element which applies a spring action. For this purpose the fastening elements24are preferably made of a flexible material. Polycarbonate proved to be particularly suitable. But naturally other materials or combinations of materials are possible too, in particular thin spring steel sheets or the like as well.

A single fastening element24can be seen inFIG. 2. The preferably rectangular and flat plates, which can also have almost any other shape, have an opening25which is designed for receiving one screen spoke17each. The opening25is designed in such a way that the fastening element24can be fitted on the screen spoke17. The position of the opening25can vary, but is preferably not at the centre M of the fastening element24. It can be seen inFIG. 2that the opening25is arranged asymmetrically. This means that the opening25is arranged eccentrically in relation to the centre M of the fastening element24. By this means, the fastening element24is virtually divided into a receiving section26, which comprises the opening25, and a holding section27, which is stitched to the diffuser element22. The diameter of the bore forming the opening25is preferably slightly larger than the largest cross-section of the screen spoke17or closure cap21. Hence on the one hand easy fitting is guaranteed, and on the other hand unwanted slipping off is prevented. The fastening element24can also be designed as a sleeve with a receptacle for a screen spoke or otherwise.

In the state fastened to the diffuser element22and not mounted on the reflector screen11, the plates extend inwardly in their longitudinal extent, starting from the outer edge28of the diffuser element22, in such a way that the plane defined by the plate runs substantially parallel or slightly at an angle to the plane defined by the extended diffuser element22(see in particularFIG. 6). In this case the transition between the diffuser element22and the fastening element24can be made by the diffuser element22itself or, as shown inFIG. 6, by an additional connecting means29. In the state of the diffuser element22mounted on the reflector screen11, a detail of which diffuser element22can be seen in particular inFIG. 4, the fastening elements24are braced relative to the screen spokes17, which project at least by their closure caps21through the opening25. With the short arm of the fastening element24, which has the opening25, the fastening element24is supported on the corresponding screen spoke17. The long arm, of which the length can vary, projects beyond the light outlet opening20and maintains the distance A. Due to the fact that several fastening elements24are distributed over the circumference and preferably also located opposite each other, virtually a self-holding effect is created, which keeps the diffuser12free from creases and at a distance A in front of the light outlet opening20.