The present invention relates to privacy films for display screens, and to methods of manufacturing thereof. In particular, the invention relates to privacy films for curved display screens, and their method of manufacture.
Privacy films (also known as “privacy coverings”, “privacy screens” or “privacy filters”) are coverings applied to display screens to limit the viewing angle of the display screen. A typical privacy film is shown in
Viewed in cross section B-B (
With a conventional privacy film, the viewing angle at each point on the screen will be symmetrical about a line perpendicular to the display screen—i.e. a viewer standing at an angle alpha on either side of the screen will be able to see it. While this is generally sufficient for flat display screens, it presents a problem for curved displays.
In general, due to the curve, a viewer who is beyond the viewing angle of the centre of the curved display may still be able to see content on a part of the curve which is angled towards them. For highly curved screens or very restrictive privacy films, a viewer standing directly in front of the screen may not be able to see all of the content on the screen if they are too far away, due to being outside of the viewing angle of some parts.
According to a first aspect of the invention, there is provided a method of manufacturing a privacy film for a curved display screen. A block is provided, comprising alternating transparent layers and opaque layers, wherein the transparent layers and opaque layers are flat. The block is cut to form a film having a curved cross section when no force is applied, with each of the transparent and opaque layers extending across the film. The cut surfaces are polished or a transparent coating is applied to the cut surfaces.
According to a second aspect, there is provided a privacy film for a curved display screen. The privacy film has a curved cross section when no force is applied. The privacy film comprises alternating transparent layers and opaque layers, each extending across the privacy film, and each parallel to the other transparent and opaque layers when no force is applied.
According to a third aspect, there is provided a method of applying a privacy film according to the second aspect to a curved display screen. The display screen has a curved cross section which has a radius of curvature which is less than a radius of curvature of the curved cross section of the privacy film. The method comprises bending the privacy film to reduce its radius of curvature during application of the privacy film.
In order to provide a useful privacy film for a curved display, the opaque elements should be parallel when the film is applied to the display—or at least at an angle between where they would be if parallel, and where they would be if a flat privacy film with parallel opaque elements was bent to fit the curved display.
US 2020/0049864 A1 discloses a way of providing this by providing a flat privacy film, with opaque elements set into it at angles such that they are parallel when the film is curved to fit the display. However, this is complex to manufacture, and may be difficult to apply due to the need to curve a film that will tend to revert towards being flat.
Instead, it is proposed herein to provide a privacy film as shown in
In order to aid in the description of the curved privacy film, an exemplary method of manufacture will now be described. However, it should be appreciated that the curved privacy film may be manufactured by other means. The method described provides one possible means of manufacture, which allows for a large number of such privacy films to be manufactured simultaneously.
The manufacturing method is illustrated in
Each of these steps will be described in more detail below.
Step 1, providing the block, can be achieved by any suitable means of providing a block with a stack of flat layers that alternate between transparent layers and opaque layers. For example, as shown in
The block may be provided with a depth perpendicular to the layers which is equal to the width of the intended final privacy film (measured across the curved cross section), and a width which is equal to the height of the final privacy film (measured perpendicular to the width of the privacy film, when viewed straight on). One way to achieve this is to manufacture a larger block (e.g. 1 meter width), and cut the large block to the required width.
The transparent layers may be made from any suitable transparent material, e.g. acrylic,
The opaque layers may be made from any suitably opaque material, or from a transparent material with an additional pigment. Where the opaque layers comprise an opaque adhesive, this opaque adhesive may comprise an adhesive and a pigment.
In step 2, the block provided in step 1 is cut to form a film (or a plurality of films) having a curved cross section. This may be achieved by making a curved slice 404 through the block, across all the layers, as shown in
In step 3, the cut surface of the privacy film 405 is polished or coated to ensure that it is smooth, at least for the transparent sections. This is because the cutting method will generally not leave a smooth surface which would allow light to pass through the privacy screen. The appropriate polishing method will depend on the material of the transparent layer, but may include any of vapour polishing 406 (
While
The privacy film may be applied to a display screen with a matching curvature. Alternatively, the privacy film may be applied to a display screen with a lower radius of curvature (for a concave screen) or a greater radius of curvature (for a convex screen), as shown in
The skilled person will understand that in the preceding description and appended claims, positional terms such as ‘above’, ‘along’, ‘side’, etc. are made with reference to conceptual illustrations, such as those shown in the appended drawings. These terms are used for ease of reference but are not intended to be of limiting nature. These terms are therefore to be understood as referring to an object when in an orientation as shown in the accompanying drawings.
The figures are schematic only, and do not represent accurate dimensions. As an example, the privacy film may be 50 microns to 300 microns thick, e.g. 200 microns thick. The transparent layers of the block (and therefore the transparent elements of the privacy film) may be 50 to 200 microns thick, e.g. 100 microns thick. The opaque layers of the block (and therefore the opaque layers of the privacy film) may be 5 to 50 microns thick, e.g. 15 microns thick.
Although the disclosure has been described in terms of examples as set forth above, it should be understood that these examples are illustrative only and that the claims are not limited to those examples. Those skilled in the art will be able to make modifications and alternatives in view of the disclosure which are contemplated as failing within the scope of the appended claims. Each feature disclosed or illustrated in the present specification may be incorporated in any embodiments, whether alone or in any appropriate combination with any other feature disclosed or illustrated herein
Number | Date | Country | Kind |
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2013870.7 | Sep 2020 | GB | national |
Filing Document | Filing Date | Country | Kind |
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PCT/SG2021/050447 | 8/3/2021 | WO |