GB2234144A

GB2234144A - Apparatus for a vdu screen filter to reduce reflections on the vdu screen

Info

Publication number: GB2234144A
Application number: GB8924146A
Authority: GB
Inventors: David Watkins
Original assignee: Good Thinking Ltd
Current assignee: Good Thinking Ltd
Priority date: 1989-10-26
Filing date: 1989-10-26
Publication date: 1991-01-23
Also published as: WO1991006971A1; AU6627890A; GB8924146D0

Abstract

When a flat filter (3) is fitted to a curved screen surround (1), light is able to pass around the edges of the filter (3) and causes reflections on the screen. The apparatus comprises one or more strips or bands (5, 7) of material for fitting along or around the edges of the filter (3) to occlude the gaps between the filter (3) and the screen surround (1) and so reduce these reflections. The apparatus may comprise substantially rigid plastics extrusions (5) and/or a band of flexible material (7) together with attachment means (6, 8) such as Velcro (trademark), and mounting means (11) as appropriate. The band of flexible material (7) is able to twist and so accommodate variations in the width of the gap between a flat filter (3) screen and a curved side of a screen surround (1). A similar band (7) may also be used to occlude a gap of varying width between other articles.

Description

APPARATUS FOR 'IDU SCREEN FILTERS This invention relates to an apparatus for VDU (Visual Display Unit) screen filters to increase their effectiveness by reducing reflections caused by ambient light.

There are a wide range of VDU screen filters available. These are used to reduce reflected glare from the screen, enhance resolution and improve contrast and user comfort. The filter typically comprises a glass or nesh screen mounted within a rigid frame, which may be moulded or constructed from plastic extrusions.

A variety of neans are provided for attaching the filter to the VDU screen.

Commonly attachment is by means of self adhesive hook and loop fastener strips, (e.g. Velcro) or simple adhesive pads, provided on the filter frane and affixed in corresponding positions on the screen surround of the VDU. Alternatively, clips and straps may be used to hold the filter against the VDU.

Bote that Ulrelcro" is a trade mark of Selectus Ltd., the U.K. nanufacturers of hook and loop fåsteners.For brevity, Velcro is used below to mean any suitable hook and loop fasteners.

VDU screens come in a variety of sizes and many have curved surrounds for both aesthetic reasons and to match the curvature of the screen itself. The screen surround is typically curved in one direction only; i.e. the vertical sides may be substantially straight but the top and bottom curved, or the top and bottom straight and the sides curved. In some cases the screen may curve in both directions, i.e. both vertically and horizontally.

The nrajority of screen filters available have, as mentioned above, a substantially rigid frame and, in most cases, the frame is flat, i.e. it is not curved to correspond to the shape of the screen surround of the VDU. It is made this way since, if a glass screen is used, it would increase the cost APPARATUS FOR VDU SCREEN FILTERS considerably if the glass also had to be made curved. Also, a curved glass screen would suffer from additional reflection problems due to its curvature. If a mesh screen is used, this needs to be held in tension by the filterscreen frame and this would be more difficult if the frame itself were curved.ln addition, the filtering characteristics of the screen would be likely to be inpaired or be less uniform if the mesh were curved.

Custom made screen filters are available in which the filter frame is shaped so as to present curved forms to match the curvature of a specific screen surround. However, as these are custom wade and can only work with the nake and size of screen they are designed to fit, they tend to be more expensive and linked to certain models.

Thus in many situations, a flat filter screen is mounted in front of a curved screen surround. In view of this, the screen filter is only mounted flush with the screen surround at the centre of the curved sides of the screen surround, i.e. the points at which the screen surround projects most towards the user.

Tapering gaps, therefore, exist between these points and the corners of the screen, and the other sides ot the filter frame are spaced from the straight sides ot the screen surround. These gaps and spaces may typically be in the range 5-15 mm.

Ambient light entering these gaps or spaces gives rise to reflections on the VDU screen and this counteracts one of the main purposes for providing the filter. This effect is accentuated by the fact that the screen brightness is usually increased when a screen filter is used, to provide a sufficiently bright display when viewed through the filter. Little further adjustment can, therefore, be made to overcome reflections caused by light entering around the edges of the filter frame.

The present invention provides apparatus to increase the effectiveness of VDU screen filters by reducing reflections caused by ambient light passing around the edges of the frame. The apparatus comprises a number of novel features APPARATUS FOR VDU SCREES fLIERS which, taken separately or in conjunction with one another, are believed to be inventive: 1. One or more strips or bands of material for fitting in the gaps between the edge of a filter and the VDU surround.

2. Xeans for attaching the strip or band to the frame of the filter and/or to the screen surround.

3. One form of strip comprises a substantially rigid component, e.g. an L shaped plastic extrusion, shaped to at least partly occlude the gap between the edge of a substantially flat filter and a straight edge of a VDU screen surround.

4. One form of band comprises a strip of flexible material e.g. cloth, of a width suitable ior at least partly occluding the gap between the edge of a substantially flat filter and the straight edge or curved edge of a V U surround.

5. One form of attachment means comprises self-adhesive velcro strips or pads. These may affix the rigid strip referred to above to the edge of the filter screen and may affix the strip of flexible material referred to above to the rigid strip.

6. The attachment means may comprise mounting components for affixing at or adjacent to the corners of the filter, e.g. by self-adhesive velcro strips.

The rigid strip and/or the strip of flexible material may then be attached to these mounting components, again by means of velcro strips.

7. The mounting components may comprise short sections similar to the rigid strip referred to above, tapered triangular components for accommodating the shapes of screen surrounds which curve in two directions or APPARATUS FOR iDU SCREEX FILTERS compressible blocks, e.g. formed of resilient foam material, for accommodating the shape of screen surrounds with different curvatures.

8. In the case of block mounting components, referred to above, the material could incorporate a loop structure (as used for felt or abrasive pads) to which velcro hooks would attach directly.

9. Apparatus for fitting to filters of different sizes and VDU screen surrounds of different curvature.

10. Apparatus suitable for uEe with existing filter screens and VDUs.

11. Apparatus substantially as described hereafter and as shown in the accompanying drawings.

The invention will now be further described, by way of example, with reference to the accoiipanying drawings, in which: Figures 1(A) and 1(B) and 1CC) show perspective views of VDUs in which the screen surrounds are curved in one direction, vertically in Figure 1(A) and horizontally in Figure 1 (B) or in both directions in Figure 1(C) Figure 2 is a plan view of a screen filter attached to a VDU of the type shown in Figure 1(B) with part of the apparatus according to one form of the invention attached thereto; Figures 3(A) and 3(Bi show alternative forms af part of the apparatus shown in Figure 2; ; Figure 4 is a perspective view of a screen filter attached to a VDU of the type shown in Figure 1(B) with apparatus according to a preferred form of the invention attached to the two sides and top of the filter frame; APPARATUS FOR 'rDU SCREEN FILTERS Figure 5 is a perspective view corresponding to that shown in Figure 4 with an alternative iorm of the apparatus according to the invention attached to the two sides ansd top of the filter screen; and Figure 6 < A) is a rear perspective view of a filter screen separated from the VDU showing two possible forms ot attachment means mountedatthecorners thereof, and Figure (B) shows a third fOrm of attachment means.

The VDUs shown in Figure 1 have a screen surround 1, curving in one or both directions. In Figure 1 < A) the screen surround 1 curves in the vertical direction. In Figure 1cub) the screen surround 1 curves in the horizontal direction. In Figure 1(C) the screen surround 1 curves in both directions.

Figure 2 illustrates the tapered gaps left between a filter 3 and the top of a screen surround 1 ol the type shown in Figure 1cub). The filter 3 is attached to the screen surround 1 by male and female self- adhesive velcro pads 4A and 4B in conventional manner. At the sides of the filter 3, the gap betweenthevertical edges of the filter 3 and the straight, vertical edges of the screen surround 1 are at least partly occluded by L-shaped plastic extrusions 5. One limb (SA) or each plastic extrusion is attached to the edge of the filter 3 by self-adhesive velcro pads 6. The other limb (5B) occludes the said gap to prevent, or at least reduce, the amount of ambient light which can reach the VDU screen around the vertical edges of the frame ot the filter 3.

The velcro pads 4A and 4B could be replaced by other conventional means for holding the filter 3 in place in front of the VDU screen.

The size of the limb 5B oi the plastic extrusion 5 is designed to correspond to the size of the gap between the sides of a typical filter and a typical VDU.

Different size extrusions can be provided for different size gaps. In another alternative the limb 5B may be flexible to allow it to be fitted to a range of different size gaps.

APPARATUS FOR VDU SCREES FILTERS Figures 3S and 3B show cross sections of alternative forms of plastic extrusion 5. These may have a T shaped cross-section as shown in Figure 3A to increase their rigidity or an angled Shaped cross-section as shown in Figure 3B. The latter is particularly suitable when when the limb 5B is designed to be flexible in the manner described above. The T-shaped cross section also covers the edge of the screen filter 3 and so enhances the appearance of the screen.

Figure 4 shows a perspective view of the arrangement shown in Figure 2 with an L-shaped plastic extrusion 5 fitted to each side of the filter 3. Across the top of the filter 3, a flexible strip 7 of cloth or other material is provided to at least partially occlude the tapering gaps 2 shown in Figure 2. This is conveniently attached to the outer faces of the limbs 5B of the extrusions by further velcro pads 8. It is foreseen that the most convenient material for the flexible strip 7 may be non-adhesive velcro ribbon which will attach directly to the pads. Because or its flexible nature, the strip 7 is able to twist as the gap 2 becomes narrower towards the middle of the upper edge of the screen filter and then twlst in the opposite direction as the gap widens again towards the other side of the screen filter 3.The flexible strip 7 is thus able to accommodate the variations in the slze of the gap 2.

Figure 5 shows an alternative arrangement to that shown in Figure 4. In this case, the plastic extrusions 5 are dispensed with and instead, mounting means (described below) are provided adjacent to each corner of the filter 3. A length of flexible tape 7 is attached to the mounting means at or under one bottom corner of the filter 3, e.g. by velcro pads 8, extends up one side of the filter 3, across the top of the filter 3 (in the manner described in relation to Figure 4) and down the other side of the filter 3 to mounting means at the other bottom corner thereof. Again, the tape 7 is of a width designed to be sufficient to substantially occlude the gap round the two sides and top of the filter 3. As the tape 7 is flexible it can, of course, be used for a variety of different size gaps and can be simply cut to length to suit the size of the filter 3.

APPARATUS FOR TbU SCREES FILTERS The arrangements shown in Figures 4 and 5 prevent light from passing round only three edges of the filter 3, the two sides and the top. It is found in practice that there is little need to occlude the gap along the bottom edge of the filter 3 as little light enters through this gap. However, the apparatus nay, if desired, be easily modified to extend round all four sides of the filter.

Figure 6 illustrates different forms of mounting means for mounting flexible strips 7 (or rigid strips) to occlude the said gaps. The mounting means shown on the left side of Figure 6 (A) comprises short sections 9 of L-shaped plastic extrusions such as those shown in Figure 2. The mounting means shown on the right side of Figure 6 (A) comprises tapered triangular corner moulding 10 which are able to accommodate the shape of a screen surround which curves in two directions. Figure 6 (B) shows a mounting comprising a triangular block 11 of resilient foam with velcro pads 12 attached to the four relevant faces.As these blocks 11 can be compressed, their size is not critical and they can be used with a range of VDUs having screen surrounds 1 with different curvatures.

Also the Velcro to the rear face of the blocks allows attachment to the corners of the screen surround, rather than the centres of two sides, thus increasing stability and avoiding the need for the filter frame to touch the screen surround for its attachment.

In a further arrangement (not shown) the triangular block may be formed of a solid or resilient foam material with a layer of looped plastic or layer of loops (corresponding to female velcro strips) bonded to or formed on the relevant taces te.g. in the manner of well-known scouring pads comprising a relatively soft spongy base and a course, more abrasive surface).A suitable loop structure could alternatively be used throughout the block (as in the construction ot felt.) fluch of the above description relates to a VDU with a screen surround curving in the horizontal direction. The apparatus described is equally applicable to a VDU with a screen surround which curves in the vertical direction as shown in Figure 1(s). In this case, there would be tapering gaps on the two sides of the filter 3 and a gap of substantially constant width along the top and bottom edges of the filter 3.

Velcro attachments have been described as these are inexpensive, convenient to use and comnon within this field. However, other forms of attachment could be used, e.g. double sided tape, press-studs or clips. In the arrangement described above, the apparatus tor occluding the gaps around the filter screen has been nounted on the frame of the filter itself. In some arrangements, it may be more convenient to attach the apparatus to the screen surround instead.

The apparatus described above provides a simple, inexpensive way of increasing the effectiveness of a VDU screen filter without the need to provide custom made filter frames tor each different type and size of VDU.

Claims

1. Apparatus for a display screen filter comprising one or more strips or bands of material for fitting along or around one or more edges of the filter so as to reduce reflections on the display screen caused by light passing around the said edges of the filter.

2. Apparatus as claimed in claim 1 comprising one or more strips of substantially rigid material, eg a piastics extrusion, for fitting along the edge of a substantially flat filter and being shaped to occlude, at least partially, a gap between the edge of the filter and a substantially flat side of a display screen surround.

3. Apparatus as claimed in claim 2 in which the strip has an L-shaped or T-shaped section, one limb of the section being for attaching the strip to the filter or to the display screen surround and the other limb of the section being for occluding the said gap.

4. Apparatus as claimed in claims 1, 2 or 3 comprising a band of flexible material, eg a cloth-like material, for fitting along or around one or more edges of the filter to occlude, at least partially, a gap between the said edge or edges of the filter and a flat or curved side of a display screen surround.

5. Apparatus as claimed in any preceding claim comprising attachment means for attaching the said one or more strips or bands of material to the filter and/or to the display screen surround.

6. Apparatus as claimed in any preceding claim comprising mounting means for attaching each corner of the filter to a display screen surround.

7. Apparatus as claimed in claim 6 in which the mounting means are shaped and/or are resilient so as to be able to fit against a curved display screen surround.

8. Apparatus as claimed in claim 6 or 7 comprising attachment means for attaching the mounting means both to the filter and to the display screen surround and for attaching the said one or more strips or bands of material to the mounting means.

9. Apparatus as claimed in any of claims 5 to 8 in which the attachment means comprises hook and loop type fasteners, eg Velcro (trademark of Selectus Ltd.).

10. Apparatus as claimed in claim 9 when dependent upon claim 2 in which attachment means is provided on one limb of the strip for attaching the strip to the filter or to the display screen surround.

11. Apparatus as claimed in claim 10 when dependent upon claim 4 in which further attachment means is provided on the other limb of the strip for attaching the band of flexible material to the strip.

12. Apparatus for a display screen filter substantially as hereinbefore described with reference to the accompanying drawings.

13. Apparatus for occluding a gap of varying width between two articles comprising a band of flexible material, eg a cloth-like material, for fittingjalong or around the said gap so that variations in the size of the gap are accommodated by twisting of the band.

14. A method of occluding a gap of varying width between two articles comprising fitting a band of flexible material, eg a cloth-like material, along or around the said gap so that variations in the width of the gap are accomodated by twisting of the band.

15. Apparatus or a method as claimed in claim 13 or 14 in which the band of flexible material comprises a ribbon of a hook and loop type fastener material, eg Velcro (trade mark of Selectus Limited).