The invention relates to a screen cloth, in particular for projection screens, comprising a support layer made of fibrous web, and a coating applied to at least one side of the support layer.

Screen cloth serve for example as projection surfaces for movie shows and slide shows and also as projection surfaces for digital image projection apparatus (beamers) for the display of TV transmissions or computer generated presentations.

In practice, screen cloth of the type indicated above have been used which have relatively small formats, e.g. up to about to 4 m, and wherein the support layer consists of a non-woven glass fibre mat.

Since electronic flat screens are increasingly used for presentations with smaller image formats, the focus in the field of projection screens shifts to larger formats. In projection screen cloths for large formats, the support layer heretofore consists of a woven fabric of cotton or polyester fibre.

However, due to a certain anisotropy between the thread and the warp direction, woven fabrics may be subject to internal strains that may cause the cloth to become distorted or wavy, in particular when it is coated, so that the behaviour of the cloth when it is suspended and/or spread flat is not satisfactory.

It is an object of the invention to provide a screen cloth with improved tear resistance and improved suspension and flat spreading characteristics.

In order to achieve this object, according to the invention, the fibrous web is a web of synthetic fibre.

Compared to non-woven glass fibre, non-woven webs of synthetic fibres have a substantially increased tear resistance, and compared to woven fabrics, they have substantially improved suspension and flat spreading characteristics, because there are no differences between the thread direction and the warp direction. As additional advantages, a high elasticity and a high shape restoration capacity and break-proofness may be achieved by a suitable selection of the synthetic fibres. Moreover, webs of synthetic fibres are hardly inflammable and can easily be dyed. For a given tear-resistance, the synthetic fibre webs have only a low weight per surface area, e.g. 10 to 200 g/m ² , pre- ferably 30 to 150 g/m ² . For these reasons, they are particularly useful as support layer for a large format projection screen cloth with a width of 5 m or more.

Useful embodiments of the invention are indicated in the dependent claims.

Suitable synthetic fibres for the none -woven web comprise for example fibres made of polyester, polyamide or polyacrylics.

The width of the screen cloth may for example amount to 5.2 m or 6 m or more.

An embodiment example will now be explained in conjunction with the drawings, wherein:

Fig. 1 is a view of a projection screen;

Fig. 2 is a schematic cross section of a screen cloth; and

Fig. 3 shows an enlarged detail of a non-woven web that forms a support layer of the screen cloth.

As an example for a way of using the cloth according to the invention, Fig. 1 shows a projection screen having a cloth 10 that is wound on a winder 12 and adapted to be drawn-out downwardly so as to be suspended from the winder. The cloth 10 has a width of 5.2 m, for example.

As is shown in Fig. 2, the cloth 10 has a support layer 14 that is made of a non- woven web of synthetic fibres and has, for example, a thickness in the order of magnitude of about 1 mm. On the front side (that is visible in Fig. 1) the cloth is preferably coated with a white, light scattering coating 16. In the example shown, a coating 18 is also ap- plied to the back side of the support layer 14. Fig. 3 shows an enlarged detail of the surface of a non-woven web 20 that forms the support layer 14, shown together with a ruler 22 for illustrating the dimensions. Thus, Fig. 3 gives an impression of the posture and distribution of the synthetic fibres in the web 20. For manufacturing the cloth 10, the web 14 is provided in the desired width, i.e. 5.2 m in this example, and is coated with the coatings 16, 18 in a doctor or knife coating process. As is known per-se, the coating 16 is formed by spreading a paste, that is based on PVC and includes softeners and chalk as filler material and Ti0 ₂ as white pigment, on the fibrous web by means of a doctor blade. The coating 18 on the back side can be formed in a similar way.

The fibrous web 20 gives the cloth 10 a high tear resistance and an excellent elastic shape restoration behaviour which assure that the cloth 10, when drawn out from the winder 12, provides a flat projection surface that has no waves or warps.