BACKGROUND OF THE INVENTION A problem that often arises in urban areas is that the erection or alteration of a building can lead to a loss of privacy for users of adjacent properties. For example a window or balcony that overlooks a neighbouring property can make the latter effectively unusable for any activity where privacy is desired. The problem is being exacerbated today in many cities and towns as planning and regulatory authorities permit progressively higher density development, with buildings being allowed to be larger than and closer to neighbouring buildings than was the case previously.

Building owners or renovators are generally reluctant to reduce the size of windows and other openings any more than is absolutely necessary to gain approval for their designs. To allow development to proceed while at least allaying the concerns of affected neighbours, one response by the authorities has been to make approval contingent on suitable screening of windows, balconies and other openings to limit or prevent observation by users of the new or renovated building of designated areas of neighbouring properties. Such screening may be provided, for example, by trees and shrubs, latticework, appropriately located walls and the like. These are sometimes provided by the owners of the new or renovated building and sometimes must be provided by the owners of the affected property.

Regulatory authorities in Australia have recognised that it is not always possible to achieve complete privacy of a neighbouring property without blocking all views from the new/renovated building. In these circumstances a compromise is sometimes reached where, for example, a screening arrangement substantially restricts the view to the neighbouring property but does not completely prevent it.

For example, the screen may provide a certain blockage percentage and,

conversely, a certain opening percentage. Under the Australian Building Regulations 1994 (SR No. 81/1994) a habitable room window or raised open space is deemed to comply with the regulations if"the direct line of site is obscured by a permanent and fixed screen which has no more than 25% of its area open". A lattice screen, typically constructed from strips of timber, is one example.

It would however be desirable to completely prevent viewing of a designated area of the neighbouring property whilst allowing views beyond that area.

The invention disclosed herein in its various embodiments provides additional and useful options to persons designing or specifying the means by which such privacy screening is provided while still maintaining views beyond the affected property.

A problem of screening of some known types is that while a designated external area is wholly or substantially unable to be seen by building occupants, there can be excessive loss of views and light due to the screening itself. The embodiments of the invention disclosed herein are intended to at least allay this problem.

A further problem is that many screening arrangements involve substantial structures-usually on the exterior of a building-which may be expensive, unsightly and maintenance-intensive. Where adjustment means are provided to allow building occupants to control the amount of natural light, the adjustability of the screen may render the screen's privacy function ineffective, thereby making the screen incapable of meeting regulatory requirements. The adjustment means may also fail after a period of use.

It should also be appreciated that prior art light control devices are not concerned with privacy. Their objective is quite different, and often conflicting. In particular, light control devices do not generally attempt to maintain views beyond the screened area.

Throughout this specification, including the claims, the term"opening"is to be construed broadly and is intended to encompass any open two dimensional plane through which a person on one side may view a desired region on the other side. The opening may thus be of restricted dimensions such as a window,

doorway, slight, porthole, air passage, gap or aperture in a wall, or may be of infinite dimensions such as the peripheral edge of a balcony, terrace, deck or parapet where there is no upper boundary to the opening, or it may be somewhere in between such as a verandah or porch which may have a floor and a ceiling but no side boundaries as such.

Further, although the field of application of the invention has been described above as the screening of designated areas from view from within a building, it is to be understood that the invention is applicable more generally to the screening of any area or object from the view of persons through an opening.

SUMMARY OF THE INVENTION According to the invention, there is provided a privacy screen for an opening, said privacy screen including : a plurality of elongate slats ; and support means adapted for supporting said slats in fixed positions relative to each other, wherein said slats are so sized and when in said fixed relative positions so spaced apart and so oriented that when said support means is secured in a defined position in or adjacent to said opening: said slats prevent viewing of a specific predetermined region on a first side of said privacy screen by persons within a specific predetermined region on a second side of said privacy screen opposite said first side, and said slats minimise interference with viewing by said persons of a desired region on said first side of said privacy screen.

In a preferred embodiment the desired region is located at a distance from the screen greater than the first specific predetermined region.

Preferably, between a pair of adjacent slats a boundary between regions viewable and not viewable from within the second specific predetermined region is defined by alignment of an edge of one of the pair of adjacent slats on the first side of the screen and an edge of the other of the pair on the second side of the screen.

The slats, are preferably substantially flat strips. The advantage of this feature is that there may be, with suitably thin strips, comparatively little interference with viewing of the desired region that is not intended to be screened

from viewing. At least a first group of the slats may lie in planes that are substantially parallel to each other. In particular, when the support means is secured in said defined position in or adjacent to the opening, the slats may lie in horizontal planes. Horizontal slats have been found in some practical cases to give good viewing of distant areas while screening designated areas near the screen. Alternatively, when the support means is secured in the defined position in or adjacent the opening all the slats may be angled upwardly in an outward direction.

In one embodiment multiple groups of slats are provided with all of the slats in the group being arranged substantially parallel to each other. A second group of slats may be provided with the slats in the second group being arranged substantially parallel to each other but not being parallel to the slats in the first group.

In one embodiment the support means is adapted to position the slats adjacent to a first pane of transparent material secured in the opening when the support means is secured in the defined position in or adjacent to the opening. In architectural applications of the screen according to the invention, this arrangement lends itself to compactness and unobtrusiveness.

The support means may include, or be adapted for securing thereto of, a pane of transparent material that in use of the screen lies adjacent to the slats. In a particularly preferred arrangement, the screen may include two panes of transparent material secured in fixed positions on opposite sides of and adjacent to the slats. Preferably, the support means includes an open support frame for supporting the slats and a glazing frame for securing thereto the two panes of transparent material on opposite sides of the slats. Such panes can prevent or limit the collection of dust that may otherwise occur over time, and that would otherwise present a cleaning problem. In this two-pane form, the screen may in fact be adapted to be secured substantially permanently in the opening and thereby to act as a double glazed window. This then has the secondary benefit of heat control.

In a preferred embodiment the open support frame is held within the glazing frame but independently therefrom such that the glazing frame is substantially isolated from any tension forces applied to the open support frame.

In this way, compression forces on the sheet of transparent material (for example glass) can be avoided or at least substantially reduced.

The pane (or at least one of the panes) of transparent material may be of any suitable material. One such material would be glass. The panes may also be of a transparent safety material so that they provide resistance to breakage where this feature is necessary as, for example, low windows, balcony panels, parapet panels and the like. A suitable material in this instance might be polycarbonate.

It is particularly desirable in the intended applications of the invention that the screen be as unobtrusive as possible. Unobtrusiveness can be assisted by the use of thin slats with minimal, or even no supports, between the ends of the slats. Very thin, flat slats, however, may tend to sag excessively. Accordingly, in one form of the privacy screen, parts of a slat spaced apart along the slat may be secured to the support means and against movement towards each other whereby to at least limit sagging of the slat. These parts of the slat may be end parts.

In another form of the privacy screen, at least a segment of a slat is maintained in tension along its length whereby to at least limit sagging of the segment. The tension may be maintained in the slat by resilient means of any suitable form, such as, for example, a spring formation.

In one possible embodiment of the privacy screen, an adjacent pair of the slats is formed from a single elongate flat strip that is changed in direction at a location on the strip by contact with a guide element secured to the support means so that segments of the strip separated by said guide element form the adjacent slats. This embodiment takes advantage of the use of thin flat strip for the slats. The strip may be maintained in tension by resilient means whereby to maintain the adjacent slats in tension. Alternatively, parts of the strip spaced apart along its length and on opposing sides of the guide element may be secured to the support means and against movement towards each other whereby to at least limit sagging of the adjacent slats. Suitable aluminium alloy material is available commercially in the form of continuous rolls of strip. However, any other suitable material, clear or opaque, may be employed.

In a preferred embodiment each slat is made of a separate thin flat strip of material which is tensioned by means of at least one resilient member fixed to the

support means, and preferably to the above mentioned open support frame.

Preferably each slat is independently tensioned by at least one separate resilient member. The resilient member may be in the form of a spring. The spring may be a corrugated length of spring steel or wire connected to the slat or it may be integral with the slat by forming a corrugation in at least one end portion of the thin flat strip of material from which the slat is made. Preferably, each of at least two adjacent slats is maintained in tension by a resilient means and the spacing between the slats is determined by a spacer component.

In one embodiment of the privacy screen the slats may be made of a clear one way view material, frosted or translucent material so as to maximise light entry through the opening (for example, into the building or the like) whilst maintaining the privacy function of the screen. Any suitable material having the desired light transmission properties may be employed. Suitable examples may include clear or translucent plastic, Mylar TM or other similar material Alternatively, or in addition, the slats may be provided with a reflective surface so as to reflect light between adjacent slats through to the other side of the opening (for example, once again, into the building).

In order to minimise interference with viewing of the desired region (such as the distant countryside) the slats should be as thin as possible. Ideally, the slats would have negligible thickness so as to present no obstruction or interference with viewing of the desired region. In practice, however, the slats must have some minimum thickness due to their physical presence. This thickness necessarily presents at least a minor, and hopefully negligible, impediment to viewing. Preferably the slats are made of the thinnest possible material the support structure allows, whether that support be lateral support to each strip and/or tension applied to the length of the strips. In a practical embodiment the strips are preferably flat, straight, thin strips of material.

Looking at this another way, the distance between the slats should be maximised for a given slat thickness, as long as the screening function is maintained. In other words, the viewing aperture should be maximised whilst the obstruction or viewing impediment should be minimised.

In an example embodiment, the thickness of each slat is preferably less than 10% of the spacing between the slats, and more preferably less than 5% of

the spacing between the slats. Accordingly, the thickness of the slats is minimised whilst the spacing between the slats is maximised, so as to minimise interference with viewing of the desired region whilst simultaneously maintaining the screening function. In a practical example, each slat is preferably less than 0.2mm thick.

In one embodiment the width of each slat is about four times the spacing between the slats. This ratio thereby determines the boundaries between the regions viewable and not viewable. Also, in this embodiment, each slat may be about 16mm wide and 0.15 mm thick and the spacing between the slats may be about 4mm.

In a further aspect of the invention, there is provided a privacy-screened window arrangement for a building wherein a privacy screen in any of the forms disclosed above (or elsewhere in this specification) is secured within an opening in a wall of a building. Alternatively, such a privacy screen may be secured as a balustrade for a balcony or the like.

In a still further aspect of the invention, there is provided a method for privacy-screening an opening in a wall of a building including the step of securing in the opening a privacy screen in any of the forms disclosed above (or elsewhere in this specification). Alternatively, a similar method could be used to provide a balustrade screen for a balcony or the like.

It is preferred to"tailor"the privacy screen to its intended location, by suitable choice of the slats'number, width, spacing and angles prior to its assembly and securing in position.

In a still further aspect of the invention there is provided a combination privacy screen and double glazed window assembly for an opening in a building wall, the assembly including: a plurality of elongate slats ; support means supporting the slats in fixed positions relative to each other; and two panes of transparent material secured in fixed positions on opposite sides of and adjacent to said slats,

wherein said slats are so sized and when in said fixed relative positions so spaced apart and so oriented that when said support means is secured in a defined position in or adjacent to said opening; said slats prevent viewing of a first specific predetermined region on a first side of said assembly by persons within a second specific predetermined region on a second side of said assembly opposite said first side; and said slats minimise interference with viewing of said persons of. a desired region on said first side of said assembly.

In a still further aspect of the invention there is provided a combination privacy screen and window assembly for an opening, the assembly including: support means for supporting the assembly relative to the opening; a plurality of elongate slats, each slat being a substantially flat strip and each slat being supported by the support means in fixed relative positions such that the slats lie in planes which are substantially parallel to each other; and two panes of transparent material secured in fixed positions on opposite sides of and adjacent to said slats.

In a still further aspect of the invention there is provided a combination privacy screen and window assembly for an opening, the assembly including: support means for supporting the assembly relative to the opening; and a plurality of elongate slats, each slat being a substantially flat strip and each slat being supported by the support means in fixed relative positions such that the slats lie in planes which are substantially parallel to each other, wherein said support means includes an open support frame supporting said slats and a glazing frame adapted to support two panes of transparent material in fixed positions on opposite sides of and adjacent to said slats.

In this specification, the term"privacy screen"is intended to be able to cover a single screen unit for either a part or a whole of an opening, (such as a window, balcony or the like) or a module that can be assembled with other modules to form a privacy screen, according to context. Further, although the embodiments of the invention described below have elongate slats whose length extends horizontally, privacy screens in which the slats extend vertically or at some other angle are not excluded from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in detail by reference to several exemplary embodiments shown in the attached diagrams, of which Figure 1 is an elevation of a window opening in a wall of a building fitted with a privacy screen according to the invention; Figure 2 is a cross-sectional view taken at station"BB"in Figure 1 of one module (designated 11 a) only, of the screen shown in Figure 1, and showing only items at station BB; Figure 3 is a cross-sectional view taken at station"AA"in Figure 1 of one module (designated 11a) only, of the screen shown in Figure 1, and showing only items at station AA; Figure 4 is a partial cross-sectional view of the window frame and privacy screen shown in Figure 1, taken at station"CC"in Figure 1.

Figure 5 is a transverse cross-section of some slats of the privacy screen shown in Figure 1; Figure 6 is a schematic elevation of a window opening in a building fitted with the privacy screen shown in section in Figure 5, from a viewpoint end-on to slats of the screen; Figure 7 is a view identical to that in Figure 5, of a screen similar to that of Figure 5 save for having wider slats ; Figure 8 is a schematic side elevation of a window opening in a building fitted with the privacy screen shown in Figure 7, from a viewpoint end-on to slats of the screen; Figure 9 is a view identical to that in Figure 7, of a screen similar to that of Figure 7 save for having angled slats ; Figure 10 is a schematic side elevation of a window opening in a building fitted with a screen according to Figure 9, from a viewpoint end-on to slats of the screen; Figure 11 is an elevation of a further embodiment of a privacy screen according to the invention; Figure 12 is a partial elevation of the screen of Figure 11, being a detail at one corner;

Figure 13 is a cross sectional view (end on to slats) of an alternative version of a module of the screen shown in Figure 1; Figure 14 is a perspective view (with some detail omitted) of a further privacy screen according to the invention; Figure 15 is a perspective view of a slat end fitting of the screen shown in Figure 14; Figure 16 is a cross sectional view through the fitting shown in Figure 15, taken at station"XX"therein ; Figures 17 and 18 are partial exploded perspective views of a privacy screen according to a further embodiment of the invention; Figures 19 and 20 are partial exploded perspective views of a privacy screen according to a further embodiment of the invention; Figures 21 and 22 are partial exploded perspective views of a privacy screen according to a further embodiment of the invention; Figures 23 and 24 are partial exploded perspective views of a privacy screen according to a further embodiment of the invention; and Figures 25 and 26 are partial exploded perspective views of a privacy screen according to a further embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring first to Figures 1 to 4, there is shown a privacy screen 1 that is a first embodiment of the invention. A wall 2 has a window opening 3 into which is fitted a window frame 4 having two stile members 5, a sill member 6 and an upper cross-member 7. To each stile member 5 is secured an upright elongate member 8 having in cross-section two flanges 9 and 10, of which flanges 9 are screwed to the stiles 5, and flanges 10 extend into the opening 3. Members 8 do not extend the full height of the stiles 5. For a reason set out below, flanges 10 have slots 71.

Members 8 retain in place three identical screen modules 11 (referred to in the Figures as 11 a, 11 b, 11 c). Using the suffix"a"to refer to components of module 11 a as representative of modules 11, screen module 11 a has upper and lower rails 12a and 13a respectively formed of rectangular cross-section strip or flat bar. Rails 12a and 13a are held parallel by connecting members 14a extending between them and secured to them by screws 15a. Connecting members 14a are perpendicular to and pass through slats 16a which extend

parallel to rails 12a and 13a. Slats 16a are formed of suitable thin flat strip material and are separated and supported by spacer collars 17a on members 14a.

The screen 1 is assembled in opening 3 as follows. After securing of members 8 to stiles 5, and assembly of each module 11, module He is positioned with its upper and lower rails 12c and 13c adjacent to members 8 with its upper and lower rails 12c and 13c at the heights of the lowest two slots 71.

Module He is then moved perpendicular to the plane of opening 3 so that rails 12c and 13c enter slots 71. Module He is then lowered onto flanges 10 of members 8 so that flanges 10 enter slots 18 on rails 12c and 13c. Module 11c is lowered onto sill 6. Module 11 b is then engaged with flanges 10 in the same way, using the next higher pairs of slots 71, and lowered onto the first module 11c.

Finally, the third module 11a is similarly engaged with flanges 10 and lowered onto the second module 11 b. If required means (not shown) may be provided to retain the three modules 11 captive or locked in place on members 8. The effect of flanges 10 entering slots 18 is that modules 11 are not able to be removed laterally.

Screen 1 when thus completed extends only partway up the window opening 3. Open space 19 in opening 3 above screen 1 allows for uninterrupted upward viewing and free entry of natural light. However, it is possible to screen an entire window opening such as opening 3 if required, and many ways to achieve this will suggest themselves to persons skilled in the art. As shown in Figure 4, privacy screen 1, when secured in place is closely adjacent to a window pane 72 in the window opening 3. It will be noted that this preferred embodiment of the invention permits a compact, non-intrusive screening arrangement to be provided for a window.

Other arrangements are possible for achieving the basic aim of securing in place in a building opening a set of slats that can be specifically sized, shaped and oriented to prevent viewing of a designated area on one side of the opening by persons on the other whilst maximising views of areas other than the designated area. Some will be disclosed hereinafter.

Turning to Figure 5, there is shown a cross-sectional view through some of the slats 16 (only) of the screen 1. Slats 16 extend horizontally between the stiles

5 and are arranged one above the other. Slats 16 are planar and their respective planes are parallel to each other in cross-section (i. e. transversely) as well as lengthwise. Lines 20 and 21 represent the angular limits of viewing by persons on the side of screen marked"A"looking through screen 1. These limits are set by alignment of edges of the slats 16. An object on the side of the screen marked"B" can only be seen by a person on side"A"whose eye is between lines 20 and 21 if the object is also between lines 20 and 21.

Figure 6 shows schematically a window 22 in a building 23. A screen 24 the same as screen 1 is installed in window 22 and extends to a height"h"above the sill 25 of window 22. Lines 26 and 27 correspond to line 20 and lines 28 and 29 correspond to line 21 and delineate the viewing limits achievable with screen 24 at its top and bottom. The shaded region 30 cannot be seen at all by a person behind window 22 whose eye height is lower than the top of screen 24. However, viewing of more distant objects in region 31 is not prevented. Light can enter largely unobstructed by screen 24, and viewing into region 32 can take place through the unscreened area above screen 24. Of course, the screen 24 can if required have the full height of the window 22. It has been found that, particularly when very thin horizontal slats are used, an aesthetically attractive screening effect can be achieved without great interference with outward views.

Figures 7 and 8 correspond to Figures 5 and 6 and are correspondingly numbered except for the addition of a suffix"d". The only difference between screen 1d and screen 1 as shown in Figure 5 is that the slats 16d in this case are wider than slats 16 shown in Figure 5, although the vertical slat-to-slat spacing is the same. The lines 20d and 21 d are at different angles to the horizontal, and the region 30d is accordingly larger than region 30. The same effect as widening of slats 16 can alternatively be achieved by reducing the slat-to-slat spacing (not shown).

Another arrangement which may be chosen is shown in Figures 9 and 10 which correspond to Figures 7 and 8 and are identically numbered except for the addition of a suffix"bb". Slats 16bb in this case extend horizontally lengthwise, are the same width as slats 16d, and are parallel in their lengthwise direction as in the arrangements above but, transversely (i. e. as seen in cross section) are arranged at a non-zero angle (x) to the horizontal. This provides for a still larger

"screened off"region 30bb, and potentially better natural lighting of the building interior, but at the expense of more interference with viewing of the region 31 bb.

In the sectional views of Figures 5,7 and 9, the slats 16,16d and 16bb are shown as parallel to each other. However, it is also possible to use non-parallel slats where required. For example (although not shown), slats that are at or below typical occupant eye heights for a particular building may be parallel (as in Figures 5 and 7) for necessary screening of a defined area below that height, with slats above that height being angled as in Figure 9, to provide for less shading of natural sunlight. This could be desired for example where a window faces south in the southern hemisphere or north in the northern hemisphere. Screen 1 could be modified in this way by suitable changes to spacer collars 17. The spacing, angle (x) and width of slats such as slats 16 can be varied either within a module 11 or from one module 11 to another.

The modular screen 1 described above is but one possible embodiment of the invention, and one way of applying it in a building. Others exist, and have particular advantages and/or applications. Some of these will now be disclosed.

Figures 11 and 12 show a privacy screen 100 according to a further embodiment of the invention. Screen 100 has a rectangular open frame 101 with upright side members 102 and upper and lower cross members 103 and 104 respectively. Frame 101 is able to be secured by any suitable means (eg by screwing) to a window frame (not shown). To each side member 102 there are secured pegs 105. An elongate flat strip 106 of a suitable material is secured at one end to frame 101 by a suitable fitting 108 and at the other end by a fitting 109. Between the fittings 108 and 109, strip 106 is led over pegs 105 in the manner shown, to define, locate and support slats 110. By suitable spacing, shaping and sizing of the pegs 105 and use of a suitable strip 106 width, desired slat 110 spacings and width can be obtained, thereby to control the screening function of screen 100 in the manner described above.

Fitting 109 (Fig 12) has barbs 111 to engage holes 112 in strip 106 and is a turnbuckle, adjustable so that slack and sag in strip 106 (hence every slat 110) can be taken up. Strip 106 can in fact be placed under significant preload tension to further remove slack and sag. In this way, the necessity for intermediate supports for slats 110 (similar to members 14) can be reduced or eliminated and

the use of a strip 106 of very small thickness facilitated. This in turn enables the screen 100 as a whole to be comparatively unobtrusive. This form of construction lends itself to parallel, horizontal-slat arrangements.

Figure 13 is a cross-sectional view (with the slats seen end-on and with minor constructional detail omitted) of a different construction of privacy screen according to another preferred embodiment of the invention. Figure 13 shows a screen module 200, with slats 204, that differs from screen module 11 c (Figure 1) in having a pane 201 of transparent material (such as glass) secured to its upper and lower rails 212 and 213 (equivalent to rails 12a and 13a) on a side of the module 200 opposite to the side that faces the pane of glass 72 in window opening 3. Screen module 200 has the advantage that it collects less dust than would module 11 c.

Another possibility is to provide a second pane of glass 214 (shown in phantom line in Figure 13) on the side of module 200 opposite to pane 201. Slats 204 are thus effectively located in a space 215 defined by upper and lower rails 212,213 and panes 201 and 214. If end walls (not shown) are also provided so that space 215 is closed at its ends, module 200 can completely avoid the problem of dust collection on slats 204.

A privacy screen having panes on both sides may if suitably constructed be used in the manner of a double glazed window module (i. e. a replacement for a single pane of glass that comprises two panes of glass held and spaced apart from each other) or as a so-called"glass brick".

Figures 14 to 16 show a further preferred embodiment of the invention, having two parallel, spaced-apart panes. Privacy screen 250 has two parallel and spaced apart panes 251 and 252 of glass. Panes 251 and 252 are secured to, and held apart at top and bottom by, cross-members 253 and 254. Slats 255 (of which only one is shown in Figure 14) are formed of thin flat strip material and extend horizontally between panes 251 and 252 from edges 256 of panes 251 and 252. Slats 255, between panes 251 and 252, are arrayed one above the other in the manner described above to provide the screening property.

Each slat 255 has, near an end, holes 257 which engage barbs 258 on a fitting 259. A coil spring 260 is located within an open-sided opening 261 in fitting 259. A further fitting 262 is shaped to hook over edges 256 of panes 251 and 252

and passes through opening 261. Coil spring 260 bears against both fittings 259 and 262 and maintains the slat 255 in tension. The other end (not shown) of each slat 255 may be anchored in the same way, or without a spring. Screen 250 may be assembled by fitting panes 251 and 252 to cross member 254, then hooking to edges 256, and sliding there along, assemblies each comprising a slat 255, end fittings 259 and 262 (with spring 260) at one end and their counterparts at the other end. Finally cross member 253 may be secured in place so that the slats are captive between panes 251 and 252. By suitable choice of dimensions for end fittings 259 and 262, or by the use of suitable spacers between them, the required spacing of slats 255 can be obtained. This form of construction lends itself to angled-slat arrangements such as that shown in Figure 9.

Figures 17 and 18 show partial perspective views of a privacy screen 300 according to a further preferred embodiment of the invention. Screen 300 has a rectangular open frame 301 with an upright side assembly 302 and a lower cross member 304. Frame 301 includes front and rear cover members 303,303'and 304, 304'. In use, the frame 301, with cover members attached, is secured within a window frame 306 of the type used in fitting a conventional double glazed window. A retaining member 307 is provided to secure the privacy screen in place.

This embodiment includes a plurality of elongate slats 310 formed from a suitable thin strip material. In this example embodiment, each slat is about 16 mm wide and 0.15 mm thick and the spacing between the slats is about 4.0 mm.

However, any alternative dimensions could be employed according to the situation. In the embodiment shown, the upright side assembly 302 includes a connecting rod 311, connecting collars 312, coil springs 313, anchor rod 314 and retaining blocks 315, as shown in detail in Figure 18. The connecting rod 311 is resiliently biased towards the anchor rod 314 by means of the coil springs 313.

Each of the slats 310 is secured to the connecting rod 311 by means of a leaf spring 316. The spacing between the slats 310 is maintained by spacers 317. The connecting collars 312 also serve as spacers.

It will be appreciated from the arrangement shown that the slats 310 are held in tension by means of the coil springs 313 and leaf springs 316. Whilst the coil springs 313 may provide the bulk of the tension force, the leaf springs 316

allow for slight differences in length of the slats 310 due to manufacturing tolerances as well as slight differences in expansion/contraction characteristics of the material used in each slat due to temperature variations.

Figures 19 and 20 show partial perspective views of a double glazed window assembly incorporating a privacy screen 400 according to a further preferred embodiment of the invention. The screen 400 has a rectangular open frame 401 with an upright side member 402 and a lower cross member 404. The frame 401 is held within a rectangular glazing frame 421, also having a side member 422 and a lower cross member 424. Panes of glass (not shown) would be held within glazing channels 425,426. As in the embodiment shown in Figures 17 and 18, the whole assembly is held within a window frame 406 of the type commonly used for double glazed windows. The privacy screen assembly 400 may accordingly be used as a"drop in"replacement for a standard double glazed window if desired.

The frame 401 is held together using corner blocks 403 which are secured to ends of the upright side member 402 and lower cross member 404 by means of bolts 403a. The glazing frame 421 is held together by means of inner corner brackets 427 and outer corner bracket 428.

The slats 410 are secured to the upright side member 402 by means of leaf springs 412 in connecting rings 416 positioned over the member 402 which are separated by spacers 417. Each leaf spring 421 has a corrugated configuration allowing it to stretch longitudinally (horizontally in the embodiment shown in the Figures) thereby applying a tension force to the slat 410. The connecting ring 416 and slat 410 may be connected by any suitable means but, in the embodiment shown, a hook and slot arrangement, 418 and 419 respectively, is employed.

In the embodiment shown in Figures 19 and 20 the spacer 417 may be formed from a suitable plastics material, possibly using an injection moulding technique, but any suitable alternative material may be employed. In this embodiment, the spacers are provided with a corrugated shape in their mid section to follow the shape of the corrugations in the adjacent springs 421.

Depending on the height of the privacy screen 400, and hence the length of the upright side member 402, it may be necessary to provide one or more

cross braces 420 to prevent the upright side members being bent inwardly as a result of the forces applied by the springs 421.

Figures 21 to 26 show alternative preferred privacy screens 500,600 and 700 which are very similar in arrangement to the privacy screen 400 shown in Figures 19 and 20. Thus, similar reference numerals have been used throughout these Figures to denote similar components. Accordingly, only the differences between the various embodiments will be described below.

Figures 21 and 22 show a privacy screen 500 wherein springs 421 in the connecting rings 416 have been eliminated. Instead, flat connector rings 531 are used to secure the slats 510 to the upright side member 402 and a corrugated spring arrangement 530 is formed directly in at least one end or both ends of each slat 510. Flat spacers 517 are provided between the connector rings 531.

This arrangement serves to simplify the manufacture of the connector rings 531 and spacers 517.

Figures 23 and 24 show a further privacy screen 600, being a further development of the privacy screen 400 shown in Figures 19 and 20. In this embodiment, the slats 610 and the connector rings 416 are formed in one piece with an aperture 633 formed directly into the material of the slats 610. A spring arrangement 630 is also formed directly into the material of each slat 610. As can be seen in Figure 24, the spacer 617 is essentially a flat construction with a recessed portion 632 to allow for the thickness of the corrugated spring arrangement 630.

Figures 25 and 26 show a further privacy screen 700 which may be used to restrict visibility not only in the vertical plane, but also in the horizontal plane.

In this embodiment, intermediate corrugated elements 733 located between each pain of slats 710 are provided to restrict visibility in a horizontal direction to a narrow region. Whilst the corrugations may be orientated such that they extend in a direction perpendicular to the length of the slats 710, they may also extend at an angle thereto. The corrugated elements 733 may be made of the same material as the slats 710 but, preferably, are made of a transparent or translucent material which would allow more natural light to pass through the privacy screen 700 but would still restrict sideward visibility.

It will also be appreciated that the intermediate strips 733 may actually replace the slats 710, the strips 733 may include connecting rings 716 in their ends to pass over the member 402 and the corrugations 733 themselves act to provide sufficient tension without additional spring arrangements.

Finally, it should be appreciated that the privacy screen of the present invention is not intended to replace sun control devices such as blinds, curtains and the like. These would still be needed, as sun control is a separate issue from privacy screening. Indeed, it has been found that the sun control and privacy objectives are often at odds and conflicting priorities are involved. The privacy screen of the present invention may thus be used in addition to traditional sun control devices.

Based on the disclosures herein, other preferred embodiments of the invention, lying within its scope, will suggest themselves to persons of ordinary skill in the art.