WO2015185083A1

WO2015185083A1 - Dynamic privacy filter

Info

Publication number: WO2015185083A1
Application number: PCT/EP2014/061337
Authority: WO
Inventors: Karthik GURUCHANDRAN
Original assignee: Vertu Corporation Limited
Priority date: 2014-06-02
Filing date: 2014-06-02
Publication date: 2015-12-10

Abstract

A dynamic privacy filter (620) having a length (L) in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width, the dynamic privacy filter (620) configured to operate in a normal mode, wherein transparency of the dynamic privacy filter (620) is not limited, and in a privacy mode, wherein transparency of the dynamic privacy filter (620) is limited, the dynamic privacy filter (620) comprising a transparent sheet (620) comprising a plurality of filter elements (640) perpendicular to the first and the second axis extending through the transparent sheet (621); a first and a second transparent electrode layer arranged on opposite sides of the transparent sheet (621) configured to apply an electric field parallel to the plurality of filter elements (640); polymer dispersed liquid crystals (PDLC) provided to the plurality of filter elements (640), the plurality of the polymer dispersed liquid crystals (PDLC) configured to be transparent in the normal mode and non- transparent in the privacy mode, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layers; and a bonding layer (880) for optically laminating the dynamic privacy filter (620) to a display (610).

Description

DYNAMIC PRIVACY FILTER

TECHNICAL FIELD

The present invention relates generally to dynamic privacy filters. The invention relates particularly, though not exclusively, to integrating the dynamic privacy filter to a display device of an apparatus.

BACKGROUND ART

Laptop or notebook computers are often used in crowded, public places such as airplanes for writing personal or otherwise confidential information. Under such circumstances, there is generally a concern a nearby person, such as the person in the next airplane seat, may be reading sensitive material. This concern keeps many people from using a laptop computer in many instances when its use would be particularly convenient. If the computer is used in this way, sensitive data may be stolen. Same problems arise when using any apparatus in public places where sensitive material is shown to a user.

Privacy may be provided during the use of a laptop computer by restricting the viewing angle through which the screen may be viewed, so that only the person sitting directly in front of the screen can read the data written on it. This angle can be limited by holding a privacy screen across the front of the computer display screen, so that the display screen can only be viewed through the privacy screen.

However, such privacy screens are clumsy to use, bad for the apparatus design and not suitable for mobile apparatuses with various display sizes or types.

Also, these privacy screens only help from preventing people who stand next to the user from viewing the screen. Additional privacy from people looking over the shoulders from behind may need to be of equal importance. Thus, especially for mobile apparatuses an improved solution is needed to provide a dynamic privacy filter operable within an apparatus with a display device that improves the usability and provides the much needed flexibility in industrial design of the product.

SUMMARY

According to a first example aspect of the invention there is provided a dynamic privacy filter having a length in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width, the dynamic privacy filter configured to operate in a normal mode, wherein transparency of the dynamic privacy filter is not limited, and in a privacy mode, wherein transparency of the dynamic privacy filter is limited, the dynamic privacy filter comprising:

a transparent sheet comprising a plurality of filter elements perpendicular to the first and the second axis extending to the transparent sheet;

a first and a second transparent electrode layer arranged on opposite sides of the transparent sheet configured to apply an electric field parallel to the plurality of filter elements;

polymer dispersed liquid crystals (PDLC) provided to the plurality of filter elements, the plurality of the polymer dispersed liquid crystals (PDLC) configured to be transparent in the normal mode and non-transparent in the privacy mode, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer; and

a bonding layer for optically laminating the dynamic privacy filter to a display.

In an embodiment, the filter elements comprising a plurality of grooves extending through the transparent sheet. In an embodiment, the filter elements comprising polymer dispersed liquid crystals (PDLC) ink elements printed to the first and the second transparent electrode layer. In an embodiment, the transparent sheet comprising at least one of the following materials:

sapphire;

polycarbonate;

polymethyl methacrylate (PMMA);

- poly ethylene terephthalate (PET);

optically clear adhesive (OCA); and

glass.

In an embodiment, the plurality of grooves filled with the polymer dispersed liquid crystals (PDLC) forming micro-louvres for the dynamic privacy filter.

In an embodiment, the first and the second transparent electrode layer comprising at least one of the following:

indium tin oxide (ITO);

- graphene; and

silver nano wires.

In an embodiment, the plurality of the polymer dispersed liquid crystals (PDLC) comprising molecules aligning themselves in a bipolar configuration.

In an embodiment, in the privacy mode, the molecules are randomly aligned causing light beams passing through the filter elements to scatter.

In an embodiment, in the normal mode, the molecules are uniformly oriented causing light beams passing through the filter elements without scattering. In an embodiment, the plurality of grooves filled with the polymer dispersed liquid crystals (PDLC) mixed with dichroic dyes forming micro-louvres for the dynamic privacy filter. In an embodiment, the display comprising at least one of the following:

a flat panel display; and

a touch sensitive display.

In an embodiment, the dynamic privacy filter being integrated to a carrier layer of the display.

In an embodiment, wherein the carrier layer comprising at least one of the following:

a cover layer of the display; and

- a cover layer of the touch sensitive display.

In an embodiment, the transparent sheet comprising sapphire and the dynamic privacy filter being integrated to a carrier layer of the display, wherein the carrier layer comprising sapphire.

In an embodiment, the sapphire comprising a sapphire crystallographic structure having a plurality of crystal planes, wherein a first crystal plane axis is configured to be perpendicular to the first and the second axis, a second crystal plane axis is configured to be parallel to the first axis and a third crystal plane axis is configured to be parallel to the second axis.

In an embodiment, the plurality of crystal planes comprising:

A-plane with A-axis configured to be a normal axis of the A-plane;

C-plane with C-axis configured to be a normal axis of the C-plane, the C- axis being perpendicular to the A-axis; and

M-plane with M-axis configured to be a normal axis of the M-plane, the M- axis being perpendicular to the A-axis and the C-axis. In an embodiment, the first crystal plane axis is the A-axis, the second crystal plane axis is the M-axis and the third crystal plane axis is the C-axis.

In an embodiment, the bonding layer comprising transparent resin.

In an embodiment, in the normal mode no electric field is applied by the first and the second transparent electrode layer; and in the privacy mode an electric field is applied by the first and the second transparent electrode layer. According to a second example aspect of the invention there is provided a display device comprising a dynamic privacy filter of the first example aspect arranged on top of the display between a user and the display.

In an embodiment, only a portion of the display is covered by the dynamic privacy filter.

In an embodiment, the display device having a length in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width, and at least one of the length or the width of the display device being greater that the length or the width of the dynamic privacy filter, respectively.

According to a third example aspect of the invention there is provided an apparatus comprising:

a display device of the second aspect;

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to:

receive control information for the dynamic privacy filter; and switch between the normal mode and the privacy mode based on the control information. In an embodiment, the at least one memory and the computer program code further configured to, with the at least one processor, cause the apparatus to:

receive the control information using at least one of the following:

user interface of the apparatus;

- predefined settings of an application providing information for the user of the apparatus; and

pre-defined settings of the apparatus.

In an embodiment, the apparatus further comprising:

at least one sensor configured to detect other users for providing additional privacy to the user of the apparatus.

According to a fourth example aspect of the invention there is provided a method for providing a dynamic privacy filter having a length in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width, the dynamic privacy filter configured to operate in a normal mode, wherein transparency of the dynamic privacy filter is not limited, and in a privacy mode, wherein transparency of the dynamic privacy filter is limited, the method comprising:

providing a transparent sheet;

laser cutting a plurality of filter elements, such as grooves, perpendicular to the first and the second axis extending through the transparent sheet;

arranging a first and a second transparent electrode layer on opposite sides of the transparent sheet configured to apply an electric field parallel to the plurality of filter elements;

providing polymer dispersed liquid crystals (PDLC) to the plurality of filter elements, the plurality of the polymer dispersed liquid crystals (PDLC) configured to be transparent in the normal mode and non-transparent in the privacy mode, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer; and

optically laminating the dynamic privacy filter to a display using a bonding layer. According to a fifth example aspect of the invention there is provided a computer program embodied on a computer readable medium comprising computer executable program code, which when executed by at least one processor of an apparatus comprising a display device of the second aspect, causes the apparatus to:

receive control information for the dynamic privacy filter; and

switch between the normal mode and the privacy mode based on the control information.

In an embodiment, a higher strength axis of a sapphire substrate is aligned with a higher stress direction of the apparatus.

The apparatus may comprise a portable apparatus, such as a tablet, a smartphone, a mobile phone, a laptop, a digital camera or a personal digital assistant (PDA), or non-portable apparatus, such as desktop computer, a monitor, a television or a display of user operable machine, for example.

Different non-binding example aspects and embodiments of the present invention have been illustrated in the foregoing. The above embodiments are used merely to explain selected aspects or steps that may be utilized in implementations of the present invention. Some embodiments may be presented only with reference to certain example aspects of the invention. It should be appreciated that corresponding embodiments may apply to other example aspects as well.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 shows some details of a mobile apparatus in which various embodiments of the invention may be applied; Fig. 2 shows an illustrative example on a display device in which various embodiments of the invention may be applied;

Fig. 3 presents a schematic view of a sapphire crystallographic structure for a display device or a dynamic privacy filter, in which various embodiments of the invention may be applied;

Fig. 4 shows a flow diagram showing operations, in accordance with an example embodiment of the invention;

Fig. 5 shows a schematic view of a sapphire crystal structure, known also as a unit cell, having a plurality of crystal planes, in which various embodiments of the invention may be applied;

Fig. 6a presents a schematic view of a display device, in privacy mode, in which various embodiments of the invention may be applied;

Fig. 6b presents a schematic view of a display device, in normal mode, in which various embodiments of the invention may be applied;

Fig. 7 presents an example block diagram of an apparatus in which various embodiments of the invention may be applied;

Figs. 8a to 8d present a schematic view of different phases to provide a dynamic privacy filter, in which various embodiments of the invention may be applied; and

Fig. 9 presents a schematic view of a system, in which various embodiments of the invention may be applied.

DETAILED DESCRIPTION In the following description, like numbers denote like elements.

Fig. 1 shows some details of a mobile apparatus 100 in which various embodiments of the invention may be applied. In an embodiment, the mobile apparatus 100 may comprise a mobile phone, a smart phone, a tablet, a laptop or any other portable apparatus. The apparatus comprises at least one cover part 1 10 for providing protection to the components of the apparatus 100 and creating desired outlook and outer design for the apparatus 100. The cover part 1 10 may comprise several separate cover parts, such as front and rear covers and even a side frame. In Fig. 1 , mainly the front cover is shown. The apparatus 100 further comprises user interface 120, 130 comprising at least one display 120. The display 120 may be a touch-sensitive display for detecting user gestures and providing feedback for the apparatus 100. The apparatus 100 may also comprise a user input device 130, such as a keypad or a touchpad, for example. Furthermore, the apparatus 100 may comprise a camera 140. No matter the described elements 1 10, 120, 130, 140 are shown on the same side of the apparatus 100, they can be located on any side of the apparatus 100. No matter a plurality of apparatus elements 120-140 are illustrated in Fig. 1 , they all need not to be included. For example, only a touch-sensitive display 120 may be included without the need for separate user input device 130.

In an embodiment, at least one of the apparatus elements 1 10, 120, 130 comprises a touch sensitive device, such as touch sensitive display, touch screen or touch sensitive cover part, for example. The cover part 1 10 may comprise a touch sensitive device to provide good-looking, strong and scratch resistant touch sensitive surface for the apparatus. The display 120 may comprise a touch sensitive device display, to provide strong and scratch-resistant touch display with minimum thickness. The user input device may comprise a touch sensitive device, such as a touchpad.

In an embodiment, the touch sensitive display 120 may form a permanent part of the cover part 1 10 or, to increase the potential for upgrading the engine throughout the life of the cover part 1 10 it may be a module that can be replaced too. Alternatively, a protective layer of the display 120 may be a part of the cover part 1 10 that layer may be independently exchanged. In further alternative embodiment the protective layer of the display 120 is integrated to the cover part 1 10. In embodiments of the invention, the touch sensitive device may provide an operating face of the device. This gives a design engineer far greater freedom to design a device with a desirable appearance. The operating face may be provided with a user input element 130, for example a key, a touchpad, or an array of such elements. The casing may be a conventional one part casing or a clam shell, or other two or more part arrangement, where the user input elements 130 or keys may be located on a different face to a display 120. In an embodiment, the apparatus 100 comprises a display device 120 comprising a dynamic privacy filter.

In an embodiment, the display device 120, such as a touch sensitive display 120 may be an exchangeable component.

In an embodiment, the dynamic privacy filter may be an accessory component to the display device 120.

Sapphire may be used for dynamic privacy filters and display devices, such as display, or touch sensitive display, for example. Sapphire has high hardness and strength. Likewise, clear ceramic can also be used which has higher hardness and strength than glass.

The present invention discusses both sapphire and alumina. The chemical composition of both is based on AI2O3. For clarifying purposes, sapphire may be understood in this context as a single crystal of alumina and alumina as a polycrystalline form of alumina (PCA).

So far sapphire has been used only as a cover glass. Traditional approaches using optical lamination of sensors to display glass and using cover layer add thickness to the display assembly and thus also to the product, and also add costs due to additional lamination and yield drop due to multiple stage laminations and handling of multiple parts, for example. To achieve better display window strength, an ion exchanged glass variant like gorilla glass may be used. Such glass is isotropic, however. This has a disadvantage that such design, when integrated with a polarizer based display solution, is not compatible with polarized sunglasses of the user. Most liquid- crystal displays (LCDs) typically have just a linear polarizer on the top surface generating linearly polarized light which is not polarized sunglass compatible. Polarizer based displays comprise, for example, a liquid-crystal display (LCD) that has a significant market share in handheld devices when compared to an emissive display solution, such as an organic light-emitting diode (OLED). To make such design compatible with polarized sunglasses, additional ¼ wave plates are laminated on to the display to circularly polarize the light from the display module. This means additional operations and elements to the liquid-crystal display (LCD) and also increases the device thickness, cost and potential yield drop due to additional lamination

Fig. 2 shows an illustrative example on a display device 200 in which various embodiments of the invention may be applied. The invention enables designing and manufacturing a dynamic privacy filter to a substrate. The privacy filter may be made out of a polyethylene terephthalate (PET) film and then laminated to sapphire, for example. The dynamic privacy filter may be attached to the display device either in the manufacturing process of afterwards as an accessory.

A sapphire layer could be used as display device, cover layer, dynamic privacy filter and touch sensor substrate and different elements may be constructed directly on sapphire when manufacturing the device. A certain sapphire plane could be selected. Such approach provides multiple benefits like very high scratch resistance and robustness when compared to glass, reduced product thickness, better yield and less complicated lamination process.

In an embodiment, the entire display solution is optimized for thickness, optical performance and reliability performance without compromising on any existing integration techniques used in the trade. Any type of display technology could be used and embodiments are not limited to displays only but any devices sharing some sensitive information are included, such as monitors, informative cover parts, touch sensitive displays, screens, laptops, and automatic teller machines (ATM), for example.

In an embodiment, sapphire or ceramic substrate could be used as one display device or touch sensor layer (say X electrode) and another material layer (film, glass, sapphire or clear ceramic) as the second layer (say Y electrode). This could give the same benefits with potentially lower manufacturing costs, but with marginally increased thickness. This way it is possible to integrate touch on sapphire and dynamic privacy. However, these can also be totally independent.

In an embodiment, all of the touch sensing electrodes for a touch sensitive display device may be placed on to a thin material (film, glass, sapphire or clear ceramic) which will perform the touch function and then this material is laminated to a sapphire or ceramic cover glass.

In an embodiment, a display device 200 for an apparatus is provided. The display device comprises a dynamic privacy filter 210 having a length in a direction of a first axis and a width in a direction of a second axis, wherein the length is greater than or equal to the width. The dynamic privacy filter may comprise a substrate comprising sapphire, a polyethylene terephthalate (PET) film, glass or similar material. The sapphire may comprise sapphire crystallographic structure having a plurality of crystal planes, wherein a first crystal plane axis is configured to be perpendicular to the first and the second axis. The dynamic filter 210 comprises a transparent sheet comprising a plurality of grooves perpendicular to the first and the second axis extending through the transparent sheet. The dynamic privacy filter 210 further comprises a first and a second transparent electrode layer arranged on opposite sides of the transparent sheet configured to apply an electric field parallel to the plurality of grooves. Furthermore, the dynamic filter 210 may comprise polymer dispersed liquid crystals (PDLC) provided to the plurality of grooves, the plurality of the polymer dispersed liquid crystals (PDLC) configured to be transparent in the normal mode and non-transparent in the privacy mode, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer. A bonding layer 220 may be used for optically laminating the dynamic privacy filter 210 to a display 230. The bonding layer 220 may comprise, for example, transparent resin. Furthermore, a metal track layer may be arranged in an edge area of the display device 200 for the transparent electrode layers, configured to provide electrical connection for the operation of the transparent electrode layers.

In an embodiment, a dynamic privacy filter 210 has a length in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width. The dynamic privacy filter 210 is configured to operate in a normal mode, wherein transparency of the dynamic privacy filter 210 is not limited, and in a privacy mode, wherein transparency of the dynamic privacy filter 210 is limited. The dynamic privacy filter 210 further comprises a transparent sheet comprising a plurality of filter elements perpendicular to the first and the second axis extending to the transparent sheet; a first and a second transparent electrode layer arranged on opposite sides of the transparent sheet configured to apply an electric field parallel to the plurality of filter elements; polymer dispersed liquid crystals (PDLC) provided to the plurality of filter elements, the plurality of the polymer dispersed liquid crystals (PDLC) configured to be transparent in the normal mode and non-transparent in the privacy mode, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer; and a bonding layer 220 for optically laminating the dynamic privacy filter 210 to a display 230.

In an embodiment, a transparent electrode pattern layer may be added to form a plurality of touch sensing elements parallel to the first axis and to the second axis, wherein the plurality of touch sensing elements configured to provide touch information using capacitive coupling. Furthermore, a metal track layer may be arranged in an edge area of the display device for the transparent electrode pattern layer, configured to provide connection for the transparent electrode pattern layer in the edge area of the touch sensitive display device 200.

In an embodiment, the transparent layer may comprise jumpers when applied directly on to sapphire. In this case, a first layer has almost all of the X and Y lines and a second layer is used only to connect the missing connections to complete the matrix using the jumpers.

In an embodiment, an index matching layer is arranged between the dynamic privacy filter 210 and the display 230 or at least one the transparent electrode pattern layers of the touch sensor layer configured to match the first and the second refractive index values; wherein at least one of the transparent electrode pattern layers of the touch sensor layer is integral (e.g. sputtered) to the substrate of the display 230.

In an embodiment, an optically clear adhesive layer 220 is used to attach at least one of the dynamic privacy filter 210, the touch sensor layer and the metal track layer to a display 230. The display 230 may comprise LCD or OLED display, for example. Furthermore, a flexible printed circuit 240 may be used for providing electrical connection for the dynamic privacy filter 210, the touch sensor layer, the metal track layer or the display 230, or for all.

Sapphire may be used as the base material to deposit the dynamic privacy filter 210 transparent electrodes, made of materials like indium tin oxide (ITO), graphene, silver nanowires etc. Suitable index matching layers may be added and tuned to effectively hide any conductive electrodes becoming otherwise visible after etching a suitable capacitive touch pattern for a touch sensitive display, for example. Etching may be done using photolithography or using laser ablation but is not limited to these technologies. Insulators can be printed using inkjet technology, for example, or can be deposited and then etched so to form a basis to make cross over electrodes or jumpers for the touch sensor. The cross over electrode or jumper may also be constructed using materials like ITO, graphene, silver nanowires, etc. Metal tracks that are made of highly conductive materials like copper or silver, for example, will be connected to the transparent electrodes and then routed to bond to a printed circuit, such as flexible circuit board 240.

In an embodiment, the metal tracks do not run in both layers. The metal tracks may be arranged on the same plane as the first transparent layer and connect to both of the X and Y tracks in the same layer. The jumpers may be located on the second layer and the second layer may not comprise any metal tracks. However the metal tracks are on each layer in the case of film sensor optically laminated to sapphire. If touch sensor is not utilized in the sapphire, no insulators or etching is required for providing dynamic privacy only.

In an embodiment, black mask ink with suitable optical density may be used to hide the metal tracks and their connection to electrodes both from the user side and the underside. The black mask ink may be applied in an inner surface between the dynamic privacy filter 210 and the display 230, for example. The metal tracks may be processed after black mask is applied, hence they are hidden from the users view. Another layer of black mask may be applied after metal tracks are etched to protect them and insulate them. Sapphire is a single crystal material, i.e. it is grown as a continuous large single crystal without grain boundaries. Such a single crystal may be grown before cutting to a desired size and shape for a display device, a carrier of a dynamic privacy filter, a substrate sheet for a dynamic privacy filter or a touch sensitive device. The sapphire single crystal, i.e., AI2O3, is used because it has higher hardness and toughness than e.g. glass. The single crystal of sapphire may be pulled, growing a seed crystal in contact with the surface of the molten alumina to produce the single crystal into a larger single crystal, so as to generally work the single crystal into the desired shape. Fig. 3 presents a schematic view 300 of a sapphire crystallographic structure 310 for a device 320, in which various embodiments of the invention may be applied.

The device 320 may be a display 230 element, a touch sensitive display 230 element or a dynamic filter 210 element of Fig. 2, for example. The device 320 is developed by growing the sapphire crystallographic structure 310. The growing may be arranged in desired planes after detecting the planes and axes of the sapphire single crystal, for example. In an embodiment, the desired dimensions of the device 320 comprise a length L over a first axis and a width W over a second axis, as shown in Fig. 3.

In an embodiment, orientation of the sapphire unit cell 310 may be selected so that the plane of the device 320, such as an optical element, corresponds to certain planes of the sapphire cell.

In an embodiment, the sapphire planes may be arranged to match a liquid-crystal display (LCD) top polarizer angle in such a way it retards one axis (called slow axis) more than the other thereby circularly or elliptically polarizing the outgoing light.

A device 320 may have a length (L) in a direction of a first axis and a width (W) in a direction of a second axis, wherein the length is greater than or equal to the width. The device comprises a substrate comprising sapphire with a first refractive index value, the sapphire comprising sapphire crystallographic structure having a plurality of crystal planes, wherein a first crystal plane axis is configured to be perpendicular to the first and the second axis. Fig. 4 shows operations in an apparatus in accordance with an example embodiment of the invention. In step 400, a method is started for providing a dynamic privacy filter having a length in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width, the dynamic privacy filter configured to operate in a normal mode, wherein transparency of the dynamic privacy filter is not limited, and in a privacy mode, wherein transparency of the dynamic privacy filter is limited. In step 410, a transparent sheet is provided. In step 420, a plurality of filter elements, such as grooves, perpendicular to the first and the second axis extending through the transparent sheet is laser cut. In step 430, a first and a second transparent electrode layer are arranged on opposite sides of the transparent sheet configured to apply an electric field parallel to the plurality of filter elements, such as grooves. Step 420 may also be skipped and polymer dispersed liquid crystals (PDLC) may just be printed on the transparent sheet. Suitable conductive electrodes will be added either through optical lamination or another suitable method, for example. In step 440, polymer dispersed liquid crystals (PDLC) are provided to the plurality of filter elements, such as grooves, the plurality of the polymer dispersed liquid crystals (PDLC) configured to be transparent in the normal mode and non- transparent in the privacy mode, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer. In step 450, the dynamic privacy filter is optically laminated to a display using a bonding layer. In step 460, the method ends. Additional sensors may be incorporated onto sapphire or on the apparatus to detect people overlooking and give some indication to the user to provide an additional dimension to privacy.

In an embodiment, the order of the steps 410 - 450 may vary. Furthermore, an index matching layer may be applied between any layers as well as any of the following: indium tin oxide (ITO) sputtering, pattern etching, insulator coating, metal track sputtering and etching finishing with a back index matching later for reduced reflection. Fig. 5 shows a schematic view of a sapphire crystal structure 500, known also as a unit cell, having a plurality of crystal planes 510 - 540, in which various embodiments of the invention may be applied. In the crystal structure of a sapphire, as shown in Fig. 5, the sapphire crystal is a hexagonal system, wherein C-axis forms a central axis being vertical and normal to C-plane 520. Due to the symmetry of the sapphire crystal structure the A-plane has numerous A-axes in Fig. 5, for example axis a1 to a3 that are to be extended in three directions perpendicular to C-axis. Respectively, A-plane 510 is shown in Fig. 5. M-plane 530 is perpendicular to C-plane 520 and A-plane 510. R-plane 540 is oblique at a constant angle to C-axis.

No matter only four planes 510 - 540 is shown, the crystal cell may comprise other planes. Furthermore, due to crystal symmetry, there may be several identical planes for each major plane. For example, the unit cell 500 may comprise three A- planes 510, three R-planes 540, one C-plane 520 and three M-planes 530, for example.

The C-axis is typically angled approximately 57.6 degrees with respect to the R- axis. The R-axis is typically angled with respect to the M-axis by approximately 32.4 degrees. The planes and axes of the sapphire can be analyzed for example with X-ray or electron diffraction and can be determined about the actual sapphire single crystal. In an embodiment, measurements of the sapphire crystal have revealed that A- plane is generally the strongest plane regarding to mechanical stress. However, the integration of sapphire to an display device or a dynamic privacy filter of an apparatus may be taken even further by controlling anisotropy (sometimes referred to as minor planes) such that the sapphire is orientated within the display device or a dynamic privacy filter of the apparatus for maximum strength and hence reliability.

In an embodiment, the crystal planes and directions in hexagonal systems may be indexed using Miller indices, wherein crystallographically equivalent planes have indices which appear dissimilar. To overcome this Miller-Bravais indexing system may be used, where a fourth index is introduced to the three of the Miller system.

A plane is then specified using four indices (hkil), where h, k, i and I are integers. The third index is always the negative of the sum of the first two and can be determined from the Miller system.

A direction is specified as [uvtw] where u, v, t and w are integers. The values of u, v and t are adjusted so that their sum is zero. The direction index cannot be written down from the equivalent Miller index.

When looking at Fig. 5 and using the Miller-Bravais indices for defining the planes, following mapping could be used:

C-plane 520 corresponds to {0 0 0 1 } of the Miller-Bravais indices; R-plane 540 corresponds to {1 0 1 2} of the Miller-Bravais indices;

A-plane 510 corresponds to {1 12 0} of the Miller-Bravais indices; and M-plane 530 corresponds to {1 0 1 0} of the Miller-Bravais indices. Referring to Fig. 3, A-plane of the sapphire cell 310 is shown. The length L in this embodiment is greater than the width W, as can be seen from Fig. 3. The sapphire crystallographic structure is configured so that a main plane of the sapphire cell 310 is set to be parallel to the surface plane of the device 320 and two minor planes are set to be parallel to the first and second axes (W and L).

In an embodiment, the device 320 of an apparatus has a length L in a direction of a first axis and a width W in a direction of a second axis, wherein the length L is greater than or equal to the width W. The device 320 is developed and comprising a sapphire crystallographic structure 310 having a plurality of crystal planes with corresponding normal axes represented as C-axis, A-axis and M-axis, for example. A first crystal plane axis is configured to be perpendicular to the first axis L and the second axis W. A second crystal plane axis is configured to be parallel to the first axis L and a third crystal plane axis is configured to be parallel to the second axis W.

In an embodiment, a sapphire crystallographic structure has a plurality of crystal planes, wherein three major planes maybe be represented by three orthogonal axis, wherein a first crystal plane axis is configured to be perpendicular to the second crystal plane axis and the third crystal plane axis is configured to be perpendicular to the first crystal plane axis and the second crystal plane axis.

The plurality of crystal planes comprise at least:

A-plane with A-axis configured to be a normal axis of the A-plane;

M-plane with M-axis configured to be a normal axis of the M-plane, the M- axis being perpendicular to the A-axis and the C-axis. In an embodiment, the plurality of crystal planes comprises:

A-plane with A-axis configured to be a normal axis of the A-plane, the A- axis being perpendicular to the C-axis and perpendicular to the M-axis; and

C-plane with C-axis configured to be a normal axis of the C-plane, the C- axis being perpendicular to the A-axis and perpendicular to the M-axis; and

M-plane with M-axis configured to be a normal axis of the M-plane, the M- axis being perpendicular to the A-axis and perpendicular to the C-axis.

In an embodiment, the first crystal plane axis is the A-axis perpendicular to the W- axis and the L-axis, the second crystal plane axis is the M-axis parallel to the L- axis and the third crystal plane axis is the C-axis parallel to the W-axis.

Configuring the sapphire crystal 310 planes so that A-plane is parallel to the surface plane of the device 320, such as a dynamic privacy filter or a display, provides improved strength for the device 320. Even further strength for the display device 320 or the dynamic privacy filter 320 is achieved by aligning the M- axis of the M-plane parallel to a longer side L of the device 320 and the C-axis of the C-plane parallel to a shorter side of the device 320. Fig. 6a presents a schematic view of a display device 600, in privacy mode, in which various embodiments of the invention may be applied.

In an embodiment, the display device 600 is not display dependent as would be the case if the privacy filter would be implemented as in-cell technology within the display and the display device 600 is also be dynamically switchable unlike the external privacy films, resulting in cheaper and more flexible integration with a wide variety of displays.

In an embodiment, a display device 600 comprises a display 610, wherein the display device 600 comprises a dynamic privacy filter 620 arranged on top of the display 610 between a user and the display 610. A viewing cone 660 is shown to illustrate an angle over which a certain portion P of the display 610 is deemed usable for the user. The user is viewing the display 610 from the direction of the viewing cone 660. The display 610 may comprise, for example, a flat panel display or a touch sensitive display.

A dynamic privacy filter 620 has a length L in a direction of a first axis and a width in a direction of a second axis (see e.g. Fig.3), the length L being greater than or equal to the width. The dynamic privacy filter 620 is configured to operate in a normal mode, wherein transparency of the dynamic privacy filter is not limited, and in a privacy mode as illustrated in Fig.6a, wherein transparency of the dynamic privacy filter 620 is limited. The dynamic privacy filter 620 comprises a transparent sheet 621 comprising a plurality of filter elements 640, such as grooves, perpendicular to the first and the second axis extending through the transparent sheet 621 . A first and a second transparent electrode layer (not shown) are arranged on opposite sides of the transparent sheet 621 configured to apply an electric field parallel to the plurality of filter elements 640. The first and the second transparent electrode may be attached to the carriers 630, 650 respectively. Polymer dispersed liquid crystals (PDLC) are provided to the plurality of filter elements 640, wherein the plurality of the polymer dispersed liquid crystals (PDLC) are configured to be transparent in the normal mode and non-transparent in the privacy mode as illustrated in Fig. 6a, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer. A bonding layer may be arranged between the carrier 650 and the display 610 for optically laminating the dynamic privacy filter 620 to the display 610. As illustrated in Fig. 6a, the viewing cone 660 is limited due to the activated privacy mode.

In an embodiment, spacing D of the filter elements, such as grooves 640, could be 50um, height H of the grooves could be 150um and width of the grooves 640 could be 15um, for example.

A scattering mode of polymer dispersed liquid crystals (PDLC) when mixed with a suitable black ink within the filter elements, such as grooves 640, is used to block light and reduce the viewing angle as illustrated by the viewing cone 660 of Fig. 6a.

The display 610 (LCD/OLED) may be driven with higher backlight level using suitable hardware and software to improve luminance that is lost due to the privacy filter.

The plurality of the polymer dispersed liquid crystals (PDLC) may comprise molecules aligning themselves in a bipolar configuration.

In an embodiment, in the privacy mode, the molecules are randomly aligned causing light beams passing through the filter elements to scatter. In an embodiment, in the normal mode, the molecules are uniformly oriented causing light beams passing through the filter elements without scattering.

In an embodiment, an external sheet 621 is patterned and the patterns, filter elements or grooves are filled with polymer dispersed liquid crystals (PDLC) mixed with dichroic dyes to create micro-louvres 640 that block light. This results in privacy performance similar to add-on static privacy films but with the improved performance of switching the different modes electrically.

In an embodiment, the micro-louvres 640 are dynamically switched from transparent to opaque state by applying electric field over them. In an embodiment, the dynamic privacy filter 620 is laminated to the display 610 optically. This results in a robust display device stack 610-620 solution and a risk of damaging the dynamic privacy filter 620, especially the sheet 621 comprising the grooves of polymer dispersed liquid crystals (PDLC) is reduced. Such approach also results in lesser processing of a privacy film with any hard coatings.

In an embodiment, if using reverse PDLC material, in the normal mode no electric field is applied by the first and the second transparent electrode layer; and in the privacy mode an electric field is applied by the first and the second transparent electrode layer. Reverse polymer dispersed liquid crystals (PDLC) could be used, which are normally transparent and change to scattering mode when a voltage over them is applied. This results in lower power consumption, when privacy mode is less frequently used than normal mode. In case where privacy mode is preferred more than normal mode, normal polymer dispersed liquid crystals (PDLC) could be used.

In an embodiment, if using normal PDLC material, in the normal mode electric field is applied by the first and the second transparent electrode layer; and in the privacy mode no electric field is applied by the first and the second transparent electrode layer.

In an embodiment, the sheet 621 may comprise a processed privacy sheet made of transparent substrate such as polycarbonate, polymethyl methacrylate (PMMA), glass or sapphire, for example. The sheet 621 may then be laminated to a display 610 cover glass and the display device 600 does not require any additional polarizers or optical films to function as a dynamic privacy filter.

The micro-louvres 640 are constructed using dye-doped polymer dispersed liquid crystals (PDLC) or reverse-PDLC. The reverse-PDLC will be non-transparent in OFF state and transparent in ON state. In ON state the transparent PDLC will let light pass normally through the louvres 640 and the user will see the display content from a wider viewing angle. In OFF state, the PDLC will turn non- transparent, thereby creating a micro-louvre 640 to block and absorb light and eventually limiting the viewing angle of the display, creating a privacy mode.

Fig. 6b presents a schematic view of a display device 600, in normal mode, in which various embodiments of the invention may be applied. In an embodiment, a display device 600 comprises a display 610, wherein the display device 600 comprises a dynamic privacy filter 620 arranged on top of the display 610 between a user and the display 610. A viewing cone 661 is shown to illustrate an angle over which a certain portion P of the display 610 is deemed usable for the user. The user is viewing the display 610 from the direction of the viewing cone 661 .

A dynamic privacy filter 620 has a length L in a direction of a first axis and a width in a direction of a second axis (see e.g. Fig.3), the length L being greater than or equal to the width. The dynamic privacy filter 620 is configured to operate in a normal mode, as illustrated in Fig. 6b, wherein transparency of the dynamic privacy filter is not limited, and in a privacy mode as illustrated in Fig.6a, wherein transparency of the dynamic privacy filter 620 is limited. The dynamic privacy filter 620 comprises a transparent sheet 621 comprising a plurality of filter elements 640, such as grooves, perpendicular to the first and the second axis extending through the transparent sheet 621 . A first and a second transparent electrode layer (not shown) are arranged on opposite sides of the transparent sheet 621 configured to apply an electric field parallel to the plurality of filter elements 640, such as grooves. The first and the second transparent electrode may be attached to the carriers 630, 650 respectively. Polymer dispersed liquid crystals (PDLC) are provided to the plurality of grooves 640, wherein the plurality of the polymer dispersed liquid crystals (PDLC) are configured to be transparent in the normal mode, as shown in Fig. 6b, and non-transparent in the privacy mode as illustrated in Fig. 6a, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer. A bonding layer may be arranged between the carrier 650 and the display 610 for optically laminating the dynamic privacy filter 620 to the display 610. As illustrated in Fig. 6b, the viewing cone 661 in normal mode of Fig. 6b is much larger than the viewing cone 660 in privacy mode of Fig. 6a

In an embodiment, spacing D of the filter elements 640, such as grooves, could be 50um, height H of the filter elements 640 could be 150um and width could be 15um, for example.

Transparent mode of polymer dispersed liquid crystals (PDLC) within the filter elements 640, such as grooves, are used to maintain the high viewing angle of the display 610. In this case, there is no drop in substantial optical quality in achieving the privacy function.

There is some drop due to additional PET films and because the transmittance of the PDLC is not 100% even in transparent mode.

In an embodiment, a polished sapphire with a desired minor plane orientation may be used as starting point for at least one of the following: the sheet 621 , the carriers 630, 650 and the display 610. Choosing certain orientation of sapphire in terms of optical performance may enable avoiding additional ¼ wave plates required to circularly or elliptically polarize light to maintain polarized sunglass compatibility.

Embodiments of the invention provide a solution that is easy to use for the end user. The dynamic privacy filter can also be integrated into the system and does not require any constant removal / adhesion to switch from one mode to another. The solution also works with any type of display and the type of display does not have any impact on the functionality of the dynamic privacy filter. In an embodiment, the filter elements 640 comprise elongated filter elements, such as elongated grooves or channels, perpendicular to the first and the second axis extending through the transparent sheet 621 .

Fig. 7 presents an example block diagram of an apparatus 100 in which various embodiments of the invention may be applied. The apparatus 100 may be a user equipment (UE), user device or apparatus, such as a mobile terminal, a smart phone, a personal digital assistant (PDA), a MP3 player, a laptop, a tablet, a personal computer monitor, a television, a screen, an ATM, or other electronic device.

The general structure of the apparatus 100 comprises a user interface 740, a communication interface 750, a processor 710, and a memory 720 coupled to the processor 710. The apparatus 100 further comprises software 730 stored in the memory 720 and operable to be loaded into and executed in the processor 710. The software 730 may comprise one or more software modules and can be in the form of a computer program product. The apparatus 100 further comprise dynamic privacy filter 770 having a length in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width, the dynamic privacy filter configured to operate in a normal mode, wherein transparency of the dynamic privacy filter is not limited, and in a privacy mode, wherein transparency of the dynamic privacy filter is limited. The dynamic privacy filter 770 comprises a transparent sheet comprising a plurality of filter elements, such as grooves, perpendicular to the first and the second axis extending through the transparent sheet; a first and a second transparent electrode layer arranged on opposite sides of the transparent sheet configured to apply an electric field parallel to the plurality of filter elements, such as grooves; polymer dispersed liquid crystals (PDLC) provided to the plurality of filter elements, such as grooves, the plurality of the polymer dispersed liquid crystals (PDLC) configured to be transparent in the normal mode and non-transparent in the privacy mode, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer; and a bonding layer for optically laminating the dynamic privacy filter to a display 765. A display device 760 of the apparatus 100 may comprise the dynamic privacy filter 770 and the display 765.

The display device 760 or the privacy filter 770 may also be integrated to another element of the apparatus 100, for example to the user interface 740.

The processor 710 may be, e.g. a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a graphics processing unit, or the like. Fig. 7 shows one processor 710, but the apparatus 100 may comprise a plurality of processors.

The memory 720 may be for example a non-volatile or a volatile memory, such as a read-only memory (ROM), a programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), a random-access memory (RAM), a flash memory, a data disk, an optical storage, a magnetic storage, a smart card, or the like. The apparatus 100 may comprise a plurality of memories. The memory 720 may be constructed as a part of the apparatus 100 or it may be inserted into a slot, port, or the like of the apparatus 100 by a user. The memory 720 may serve the sole purpose of storing data, or it may be constructed as a part of an apparatus serving other purposes, such as processing data.

The user interface 740 may comprise circuitry for receiving input from a user of the apparatus 100, e.g., via a keyboard, graphical user interface shown on the display 765 of the user apparatus 100, speech recognition circuitry, or an accessory device, such as a headset, and for providing output to the user via, e.g., a graphical user interface or a loudspeaker. The display 765 of the user interface 740 may comprise a touch-sensitive display. The display device 760 may be integrated to the user interface 740, such as a display, a keyboard, or a touchpad. The display device 760 may also be integrated to a touch sensitive device and may also be integrated to a cover part of the apparatus 100. The privacy filter 770 may also be integrated to a cover part of the apparatus.

The dynamic privacy filter 770 may also provide a protective sheet for an element of the apparatus 100. In an example embodiment, a dynamic privacy filter 770 is configured to provide a protective sheet for the display device 760 of the apparatus 100. The dynamic privacy filter may even cover at least a part of the front, rear or side surface of the apparatus 100 cover comprising information displaying element.

The communication interface module 750 implements at least part of radio transmission. The communication interface module 750 may comprise, e.g., a wireless interface module. The wireless interface may comprise such as near field communication (NFC), a WLAN, Bluetooth, infrared (IR), radio frequency identification (RF ID), GSM/GPRS, CDMA, WCDMA, LTE (Long Term Evolution) radio module or wireless power charging. The communication interface module 750 may also be integrated into the user apparatus 100, or into an adapter, card or the like that may be inserted into a suitable slot or port of the apparatus 100. The communication interface module 750 may support one radio interface technology or a plurality of technologies. The apparatus 100 may comprise a plurality of communication interface modules 750. In an embodiment, a sensor may be integrated to the apparatus 100 for sensing a person behind the user of the apparatus 100 and trying to view the display 765 over the shoulder of the user, for example. Such sensor may comprise a motion or heat detection sensor, for example. A skilled person appreciates that in addition to the elements shown in Fig. 7, the apparatus 100 may comprise other elements.

Figs. 8a to 8d present a schematic view of different phases to provide a dynamic privacy filter, in which various embodiments of the invention may be applied.

In Fig. 8a, a transparent solid sheet 810 is first provided. The sheet 810 has a length L in a direction of a first axis, a width in a direction of a second axis and a height H in a direction of a third axis that is perpendicular to both the first and the second axis,

In next phase, as illustrated in Fig. 8b, laser cutting or a suitable alternate method, for example photolithography can be used depending on the base material used, to create a plurality of filter elements 820, such as grooves, perpendicular to the first and the second axis extending through the transparent sheet 810. A carrier 830 may be provided to support the laser cut sheet portions 840.

In next phase, as illustrated in Fig. 8c, a transparent electrode layer 850 on a first side of the transparent sheet 810, 840 is provided. The transparent electrode layer 850 may be provided using indium tin oxide (ITO) coating, for example. The transparent electrode layer 850 is configured to apply an electric field parallel to the plurality of filter elements 820, such as grooves. In next phase, as illustrated in Fig. 8d, polymer dispersed liquid crystals (PDLC) are provided to the plurality of filter elements 820, such as grooves. Furthermore a second transparent electrode layer 860 on a second side of the transparent sheet 810, 840 is provided. The second transparent electrode layer 860 may be provided using indium tin oxide (ITO) coating, for example. The second transparent electrode layer 850 is configured together with the first transparent electrode layer 830 to apply an electric field parallel to the plurality of filter elements 820, such as grooves. A second carrier 870 may be provided to support the laser cut sheet portions 840 and the transparent electrode layer 860.

In an alternate solution, first an ITO coated substrate is taken and is printed with PDLC. A second ITO coated substrate is also printed with PDLC and then these are laminated together to form a dynamic privacy filter. The other side of the ITO film might be previously processed to form a touch sensor.

The plurality of the polymer dispersed liquid crystals (PDLC) are configured to be transparent in the normal mode and non-transparent in the privacy mode, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer 830, 860. A bonding layer 880 may also be provided for optically laminating the dynamic privacy filter 810-870 to a display device (not shown).

Additionally, index matching layer may be applied. Such layer is to match the refractive indices of, for example, sapphire sheet elements 840 with the transparent conductive electrode layers 830, 860.

In an embodiment, the transparent conductive electrode layers 830, 860 may be arranged on sapphire 810, 840 surface. If the display device is not optically laminated to the dynamic privacy filter 810 - 870, additional index matching layers (sometimes referred to back index matching) will be required on top of the display device to reduce reflections arising due to refractive index mismatch between e.g. sapphire (or indium tin oxide (ITO)) and the air gap used. In some cases, a back index matching may be used either way to optimize indium tin oxide (ITO) edge visibility, even when the display device is optically laminated to the dynamic privacy filter 810 - 870. In an embodiment, reflections may be reduced using a textured structure on a surface of a sapphire substrate of the carrier 870. The textured features may reduce the reflection by either 'trapping' incident light within the structure and or by creating a gradual change in the overall structure's refractive index. The structure can be applied to the screen as a surface coating or film or be an inherent part of the carrier 870. A textured structure created as part of the sapphire screen surface may be a permanent and robust solution for reducing the reflectance from a sapphire mobile apparatus screen.

In an embodiment, at least one of the first transparent electrode layer 830, 860, the carrier 850, 870 and the second transparent electrode layer 860 may be integrated to another layer, such as to the substrate sheet element 810, 840 for example. The sheet may comprise sapphire.

At least one of the transparent electrode layers 830, 860 comprise at least one of the following: indium tin oxide (ITO), graphene and silver nano wires.

In an embodiment, a plurality of crystal planes of sapphire used for a carrier 850, 870 or the sheet 810, 840 are arranged to match a liquid-crystal display (LCD) top polarizer angle of the display and configured to circularly or elliptically polarize outgoing light.

In an embodiment, the polymer dispersed liquid crystals (PDLC) material (mixed with dichroic dyes) may be printed onto the top and bottom side of a transparent sheet 810 to perform a privacy function similar to the micro-louvre structure. The transparent sheet 810 can be a touch sensor in an example, this will reduce any additional material, laminations and thicknesses involved. Fig. 9 presents a schematic view of a display device, in which various embodiments of the invention may be applied. In an embodiment, a display device 900 comprises a display 910, wherein the display device 900 comprises a dynamic privacy filter 920 arranged on top of the display 910 between a user and the display 910. A viewing cone 960 is shown to illustrate an angle over which a certain portion P of the display 910 is deemed usable for the user. The user is viewing the display 910 from the direction of the viewing cone 960.

A dynamic privacy filter 920 has a length L in a direction of a first axis and a width in a direction of a second axis (see e.g. Fig.3), the length L being greater than or equal to the width. The dynamic privacy filter 920 is configured to operate in a normal mode, wherein transparency of the dynamic privacy filter is not limited, and in a privacy mode, wherein transparency of the dynamic privacy filter 920 is limited. The dynamic privacy filter 920 comprises a transparent sheet 921 comprising a plurality of filter elements 940, such as printed PDLC ink elements. The sheet 921 may comprise, for example, optically clear adhesive (OCA). A first and a second transparent electrode layer (not shown) are arranged on opposite sides of the transparent sheet 921 configured to apply an electric field to the plurality of filter elements 940, such as PDLC ink elements. The first and the second transparent electrode may be attached to the carriers 930, 950 respectively. Polymer dispersed liquid crystals (PDLC) are provided to the plurality of filter elements, such as PDLC ink elements, wherein the plurality of the polymer dispersed liquid crystals (PDLC) are configured to be transparent in the normal mode and non-transparent in the privacy mode as illustrated earlier in Fig. 6a, wherein a change between the normal mode and the privacy mode is based on the electric field applied by the first and the second transparent electrode layer. A bonding layer may be arranged between the carrier 950 and the display 910 for optically laminating the dynamic privacy filter 920 to the display 910. In an embodiment, spacing D of the filter elements 940, such as PDLC ink elements, could be 30um, height H of the sheet 921 could be 75um and width of the elements 940 could be 60um, for example. In an embodiment presented in Fig. 9, no laser grooves are involved and just printing methodology is employed. However, the dimensions of the PDLC ink elements 940 needs to be trialled and fine-tuned to be able to achieve the right amount of privacy i.e a tight viewing cone 960. This method has an advantage over the first method proposed (using micro-louvres) as it involves just printing the PDLC ink elements 940 and involves much less processing and hence reduces cost and improves yield.

In an embodiment, a thin layer of a polymer dispersed liquid crystal (PDLC) ink 940 is printed on the bottom side of an indium tin oxide (ITO) coated polyethylene terephthalate (PET) film 930, where the top side is etched to form one part of a touch sensor for the display device 910.

Another layer of a polymer dispersed liquid crystal (PDLC) ink is printed on the top side of an indium tin oxide (ITO) coated polyethylene terephthalate (PET) film 950, where the bottom side is etched to form another part of a touch sensor.

The two pet films 930, 950 are laminated together with a suitable thickness of optically clear adhesive (OCA) 921 . The OCA 921 is sandwiched between the two layers of PDLC ink elements 940 and both layers of PDLCs can switch from transparent to opaque to form a dynamic privacy filter 920.

Various embodiments have been presented. It should be appreciated that in this document, words comprise, include and contain are each used as open-ended expressions with no intended exclusivity. The foregoing description has provided by way of non-limiting examples of particular implementations and embodiments of the invention a full and informative description of the best mode presently contemplated by the inventors for carrying out the invention. It is however clear to a person skilled in the art that the invention is not restricted to details of the embodiments presented above, but that it can be implemented in other embodiments using equivalent means or in different combinations of embodiments without deviating from the characteristics of the invention.

Claims

Claims:

1 . A dynamic privacy filter having a length in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width, the dynamic privacy filter configured to operate in a normal mode, wherein transparency of the dynamic privacy filter is not limited, and in a privacy mode, wherein transparency of the dynamic privacy filter is limited, the dynamic privacy filter comprising:

2. The dynamic privacy filter of claim 1 , wherein the filter elements comprising a plurality of grooves extending through the transparent sheet.

3. The dynamic privacy filter of claim 1 , wherein the filter elements comprising polymer dispersed liquid crystals (PDLC) ink elements printed to the first and the second transparent electrode layer.

4. The dynamic privacy filter of any of claims 1 to 3, wherein the transparent sheet comprising at least one of the following materials: sapphire; polycarbonate; polymethyl methacrylate (PMMA); poly ethylene terephthalate (PET); optically clear adhesive (OCA); and glass.

5. The dynamic privacy filter of claim 2, wherein the plurality of grooves filled with the polymer dispersed liquid crystals (PDLC) forming micro-louvres for the dynamic privacy filter.

6. The dynamic privacy filter of any of claims 1 to 5, wherein the first and the second transparent electrode layer comprising at least one of the following: indium tin oxide (ITO); graphene; and silver nano wires.

7. The dynamic privacy filter of any of claims 1 to 6, wherein the plurality of the polymer dispersed liquid crystals (PDLC) comprising molecules aligning themselves in a bipolar configuration.

8. The dynamic privacy filter of claim 7, wherein in the privacy mode, the molecules are randomly aligned causing light beams passing through the filter elements to scatter.

9. The dynamic privacy filter of claim 7, wherein in the normal mode, the molecules are uniformly oriented causing light beams passing through the filter elements without scattering.

10. The dynamic privacy filter of claim 2, wherein the plurality of grooves filled with the polymer dispersed liquid crystals (PDLC) mixed with dichroic dyes forming micro-louvres for the dynamic privacy filter.

1 1 . The dynamic privacy filter of any of claims 1 to 10, wherein the display comprising at least one of the following: a flat panel display; and a touch sensitive display.

12. The dynamic privacy filter of claim 1 1 , wherein the dynamic privacy filter being integrated to a carrier layer of the display.

13. The dynamic privacy filter of claim 12, wherein the carrier layer comprising at least one of the following: a cover layer of the display; and a cover layer of the touch sensitive display.

14. The dynamic privacy filter of any of claims 1 to 13, wherein the transparent sheet comprising sapphire and the dynamic privacy filter being integrated to a carrier layer of the display, wherein the carrier layer comprising sapphire.

15. The dynamic privacy filter of any of claims 4 to 14, wherein the sapphire comprising a sapphire crystallographic structure having a plurality of crystal planes, wherein a first crystal plane axis is configured to be perpendicular to the first and the second axis, a second crystal plane axis is configured to be parallel to the first axis and a third crystal plane axis is configured to be parallel to the second axis.

16. The dynamic privacy filter of claim 15, wherein the plurality of crystal planes comprising:

A-plane with A-axis configured to be a normal axis of the A-plane;

M-plane with M-axis configured to be a normal axis of the M-plane, the M- axis being perpendicular to the A-axis and the C-axis.

17. The dynamic privacy filter of claim 16, wherein the first crystal plane axis is the A-axis, the second crystal plane axis is the M-axis and the third crystal plane axis is the C-axis.

18. The dynamic privacy filter of any of claims 1 to 17, wherein the bonding layer comprising transparent resin.

19. The dynamic privacy filter of any of claims 1 to 18, wherein in the normal mode no electric field is applied by the first and the second transparent electrode layer; and in the privacy mode an electric field is applied by the first and the second transparent electrode layer.

20. A display device comprising a dynamic privacy filter of any of claims 1 to 19 arranged on top of the display between a user and the display.

21 . The display device of claim 20, wherein only a portion of the display is covered by the dynamic privacy filter.

22. The display device of claim 20 having a length in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width, and at least one of the length or the width of the display device being greater that the length or the width of the dynamic privacy filter, respectively.

23. An apparatus comprising:

a display device of any of claims 20 to 22;

at least one processor; and

at least one memory including computer program code;

receive control information for the dynamic privacy filter; and switch between the normal mode and the privacy mode based on the control information.

24. The apparatus of claim 23, wherein the at least one memory and the computer program code further configured to, with the at least one processor, cause the apparatus to:

receive the control information using at least one of the following:

- user interface of the apparatus;

- pre-defined settings of the apparatus.

25. The apparatus of claim 23, further comprising:

26. A method for providing a dynamic privacy filter having a length in a direction of a first axis and a width in a direction of a second axis, the length being greater than or equal to the width, the dynamic privacy filter configured to operate in a normal mode, wherein transparency of the dynamic privacy filter is not limited, and in a privacy mode, wherein transparency of the dynamic privacy filter is limited, the method comprising:

providing a transparent sheet;

laser cutting a plurality of filter elements perpendicular to the first and the second axis extending through the transparent sheet;

optically laminating the dynamic privacy filter to a display using a bonding layer.

27. A computer program embodied on a computer readable medium comprising computer executable program code, which when executed by at least one processor of an apparatus comprising a display device of any of claims 18 to 20, causes the apparatus to:

receive control information for the dynamic privacy filter; and