WO2024170070A1

WO2024170070A1 - Apparatus and method for tensioning a rollably extending display

Info

Publication number: WO2024170070A1
Application number: PCT/EP2023/053696
Authority: WO
Inventors: Eetu PELTOLUHTA; Mika Ojanto
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2023-02-15
Filing date: 2023-02-15
Publication date: 2024-08-22

Abstract

An apparatus comprises a rollably extending display (1), a first frame (6) and a second frame (5). The second frame is movable for extending a viewing area of the display. The apparatus comprises a first wire system for tensioning a first side of the display and a second wire system comprising a second wire (12) for tensioning a second side of the display. The first wire system comprises a first spring (3) for lowering the tension sensitivity of the first wire to the length of the first wire and the second wire system comprises a second spring (13) for lowering the tension sensitivity of the second wire to the length of the second wire.

Description

APPARATUS AND METHOD FOR TENSIONING A ROLLABLY EXTENDING DISPLAY

TECHNICAL FIELD

The present disclosure relates to rollably extending displays.

BACKGROUND

Rollably extending displays can allow at least a part of the device to be rolled into a device housing. Presently are proposed technologies, which involve a pulley system and a wire to indirectly connect the two display ends and keep the display under tension at all times.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

It is an object to provide an apparatus with improved balance for tensioning a rollably extending display.

The foregoing and other objects may be achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

According to a first aspect, an apparatus comprising a rollably extending display is disclosed. The display comprises a first end and a second end. The apparatus comprises a first frame, which may be attached to the first end of the display. The apparatus also comprises a second frame, which may be attached to the second end of the display. The second frame is movable with respect to the first frame in a first direction for extending a viewing area of the display. The apparatus comprises a first wire system comprising a first wire for tensioning a first side of the display upon movement of the second frame with respect to the first frame. The apparatus also comprises a second wire system comprising a second wire for tensioning a second side of the dis-play upon movement of the second frame with respect to the first frame. The first wire system comprises a first spring for lowering the tension sensitivity of the first wire to the length of the first wire. The second wire system comprises a second spring for lowering the tension sensitivity of the second wire to the length of the second wire.

As the tension of each of the two wires is not that sensitive to the length of the corresponding wire, the balance for tensioning can be improved. The tension of the first wire and the tension of the second wire, and thus a tension for the display, can therefore be made such that it is not proportional only to the length of the wire. This can allow avoiding over- and/or under-tensioning when the length of the first wire is different from that of the second wire. It can even prevent one of the wires coming completely loose. Difference in tension on the first side and the second side of the display can thus be reduced or removed altogether, which can prevent planar overturning moment in the display. The solution allows improving evenness of the surface of the display and decreasing friction.

In an implementation form, the first spring is a cantilever spring. This allows the spring for the first wire system to be provided with a reduced thickness, for example in comparison to a coil type spring. It can also allow introducing increased tension forces, for example in comparison to a coil type spring, allowing improved flatness of the display.

In an implementation form, the cantilever spring is positioned lying on the second frame in a second direction. This allows the thickness of the first wire system to be reduced while still allowing the cantilever spring to lower the tension sensitivity of the first wire.

In an implementation form, the second direction is perpendicular with respect to the first direction. This allows improved force control for the tensioning, in turn allowing smaller components such as a smaller cantilever spring to be used.

In an implementation form, a width of the cantilever spring in the first direction is larger than a depth of the cantilever spring in a depth direction perpendicular to the first direction and the second direction. The mass required to provide the cantilever effect can thus be distributed along a plane parallel to the surface of the display, thereby allowing smaller devices to be produced. In an implementation form, the first wire is routed around an end of the cantilever spring. This allows the entire length of the cantilever spring to be utilized for a lever effect.

In an implementation form, the first wire and/or the second wire is tensioned from the first end of the display in parallel with the first direction. Aligning the tensioning with the relative movement of the first frame and the second frame allows improving the reliability of the tensioning.

In an implementation form, the first wire and/or the second wire is tensioned from the second end of the display in parallel with the first direction. Aligning the tensioning with the relative movement of the first frame and the second frame allows improving the reliability of the tensioning.

In an implementation form, the first wire system comprises an additional spring for the lowering of the tension sensitivity. The use of multiple springs for a single wire allows fine control of the tensioning properties. The additional spring may be attached to the first frame. In particular, the additional spring may be attached to a different frame than the first spring and/or the second spring, allowing yet improved control as the additional spring and the first/second spring are abutted by different frames.

In an implementation form, the additional spring is a coil spring. Using a coil spring allows leaving more room for the display to travel when rollably extending, e.g. at the backside of the apparatus.

In an implementation form, the apparatus comprises a movable wire clamp for attaching the first wire to one of the two frames, e.g. to the first frame. The additional spring can thus be arranged to cushion the movement of the wire clamp. This allows a resilient configuration to be compactly provided for attaching the first wire to the corresponding frame.

In an implementation form, the additional spring is arranged to cushion the movement of the wire clamp in the first direction. Aligning the cushioning with the relative movement of the first frame and the second frame allows improving the reliability of the tensioning.

In an implementation form, the first wire system is symmetric with respect to the second wire system. This can improve ease and reliability of providing symmetric tensioning for the display. In an implementation form, the apparatus is a mobile phone.

According to a second aspect, a method of tensioning a rollably extending display is provided. The display may be the display of an apparatus according to the first aspect. The method comprises lowering the tension sensitivity of a first wire to the length of the first wire with a first spring and lowering the tension sensitivity of a second wire to the length of the second wire with a second spring. The method further comprises tensioning a first side of the display upon extension of the display with the first wire and tensioning a second side of the display upon extension of the display with the second wire.

A spring as part of the wire system(s) allows lowering the tension sensitivity to wire length to maintain the corresponding wire under tension even if the wire elongates slightly due to creep or other factors. This way, when two or more wires are used, it can be arranged that none of these wires will lose all of its tension, and thus all wires shall share the tension of the display. With such balancing, the tension can be shared between the two or more wires, such as the first wire and the second wire, up to the point where the tension is shared equally.

Generally, spring force effected on a spring, such as the first spring and/or the second spring, is proportional to how much said spring is displaced. In practice, the wire tension can still change between wires of different length, as the spring displacement can be different. However, utilizing springs of increased length and/or wires with as little variation in length as possible, differences in tension for different wires can be decreased, for example up to the point where the tension are substantially equal.

In accordance with the present disclosure, one or more dedicated springs may be included for each individual wire for tensioning the display. Tensioning the display utilizing springs in addition to the wires allows solving an issue of the flexible display buckling under compression, which otherwise can result in increased friction or even jamming. Tensioning the display utilizing springs in addition to the wires can also allow reducing, or even substantially eliminating, the bump effect (e.g. described as display stiffness forcing itself outwards around a bend), which is a major issue for conventional rollable displays, in particular in mobile phones. Adding springs to the wire systems can reduce or substantially eliminate uneven tension distribution between two or more wires when length variations exist, for example due to manufacturing and/or assembly tolerances, and/or wire creep. Such uneven tension distribution can otherwise result in uneven surface flatness of the display.

It is to be understood that the aspects and implementation forms described above may be used in any combination with each other. Several of the aspects and implementation forms may be combined together to form a further implementation form of the invention.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding and constitute a part of this specification, illustrate examples and together with the description help to explain the principles of the disclosure. In the drawings:

Figs, la and lb illustrate an apparatus according to an example,

Fig. 2 illustrates a close-up view of an apparatus according to an example,

Fig. 3 illustrates a detail-level view of an apparatus according to an example,

Fig. 4 illustrates another detail-level view of an apparatus according to an example,

Fig. 5 illustrates yet another detail-level view of an apparatus according to an example, and Fig. 6 illustrates a method according to an example.

Like references are used to designate equivalent or at least functionally equivalent parts in the accompanying drawings.

DETAILED DESCRIPTION

The detailed description provided below in connection with the appended drawings is intended as a description of examples and is not intended to represent the only forms in which the example may be constructed or utilized. However, the same or equivalent functions and structures may be accomplished by different examples.

For instance, it is understood that a disclosure in connection with a described method may also hold true for a corresponding apparatus, device or system configured to perform the method and vice versa. For example, if a specific method step is described, a corresponding device may include a unit to perform the described method step, even if such unit is not explicitly described or illustrated in the figures. On the other hand, for example, if a specific apparatus is described based on functional units, a corresponding method may include a step performing the described functionality, even if such step is not explicitly described or illustrated in the figures. Further, it is understood that the features of the various example aspects described herein may be combined with each other, unless specifically noted otherwise.

Figs, la and lb illustrate an apparatus 100 according to an example. The apparatus may be a component, such as a display unit, or a self-contained apparatus, such as a user device. In particular, the apparatus may be a mobile device, for which the size of the apparatus becomes particularly relevant. As an example, the apparatus may be a mobile phone or a wearable device, such as a smart watch. However, the apparatus may also be a larger device such as a tablet or a laptop computer. Fig. la may be seen to illustrate a back view of the apparatus in a closed position. Similarly, Fig. lb may be seen to illustrate a back view of the apparatus in an open position. Herein, “the open position” may refer to the open position of the apparatus corresponding to an open position of the display and “the closed position“ may refer to the closed position of the apparatus corresponding to a closed position of the display.

The apparatus 100 comprises a display 1, which can be rollably extended. Herein, such a reliably extending display may be understood correspond to a flexible display arranged to be rollably drawn from a closed position to an open position to extend a viewing area of the display. This can be arranged to be performed by a linear motion, when the display is wrapped around an axis so that the linear motion rolls the display about the axis to extend the viewing area. Here, the linear motion may be perpendicular to the axis and away from the axis. The linear motion for extending the display can be arranged to be performed in the plane of the display. For the display and/or the apparatus, a moving state may be defined as a state where the viewing area of the display is changed by the reliable movement, for example from a closed position to an open position or from an open position to a closed position, whereas a stationary state may be defined as a state where the viewing area of the display is maintained, for example by maintaining the display in an open position or in a closed position.

The display 1 can be an electronic visual display provided by any of the technologies available to the person skilled in the art of such displays, for example an electroluminescent display, a liquid crystal display, a light-emitting diode display or a quantum dot display. The apparatus may comprise a display back support 7 for supporting the display. It may be laminated to the display. The display 1 has a first end and a second end, which may be considered as opposing ends for the display, e.g. as a front end and a back end for the display. The linear motion as described above may be arranged to be performed in the direction from the axis towards the front end or the back end. The display also has a first side and a second side, which may be considered as opposing sides for the display, e.g. as an upper side and a lower side for a horizontal display mode or as a left side and a right side for a vertical display mode.

The apparatus 100 comprises a first frame 6, which may be attached to the first end of the display. Similarly, the apparatus comprises a second frame 5, which may be attached to the second end of the display.

It should be understood that “end” here does not necessarily mean the ultimate edge of the display but a region that may extend along the length of the display. Accordingly, any such attachments referred herein may be performed at the edge of the display and/or at one or more points along the length of the display. The first and/or the second frame may be substantially rectangular or of any other shape for supporting the display. The second frame is arranged to be movable with respect to the first frame in a first direction for extending a viewing area of the display. This first direction may be considered as the direction for the linear motion as described above. In an example, the second frame 5 is arranged as a sliding frame to be slid open for extending the display. The first frame 6 may then be arranged as a fixed frame, for example to be maintained fixedly positioned by a user, e.g. in a hand of the user. Above, the role of the first frame and the second frame may also be interchanged. In some embodiments, the sliding frame may be partially or fully enclosed within the fixed frame in the closed position.

As an example, the sliding frame, e.g. the second frame, may be non-fixedly attached to an end of the display. The fixed frame, e.g. the first frame, may be fixedly attached to another end of the display. In general, two frames may be arranged to extend away from each other, thus extending the display area on one side while decreasing on the other. This may be arranged to take place through linear movement so that the first and second end of the display move in opposite directions.

It is not necessarily impossible to open and close the apparatus by just manipulating the distance of the two frames, having the display in zero tension. However, as the display is flexible, in particular at the area which bends over axis as described above, it may buckle under compression, e.g. when the apparatus/display is moved from an open position to a closed position and the display is thus forced to go through a bend. Increasing flexibility can also increase probability of buckling.

The apparatus 100 comprises a first wire system comprising a first wire 2 for tensioning the first side of the display upon movement of the second frame with respect to the first frame. The apparatus also comprises a second wire system comprising a second wire 12 for tensioning the second side of the display upon movement of the second frame with respect to the first frame. In both cases, the movement may be linear movement as described above, in particular in the first direction. The first and/or the second wire may be arranged at an edge of the display, e.g. along the edge, but this is not necessary in all embodiments. The first wire and/or the second wire may be tensioned from the first end of the display, for example in parallel with the first direction. Alternatively or additionally, the first wire and/or the second wire may be tensioned from the second end of the display, for example in parallel with the first direction. The sliding frame may be arranged to slide out from the fixed frame, while keeping the first wire and the second wire tensioned.

The first wire 2 and/or the second wire 12 may be provided as a continuous piece of wire or as a segmented wire. The first wire and the second wire may be arranged to be parallel for tensioning the display. The first wire may be arranged to be attached, directly or indirectly, to the first end and to the second end of the display. The second wire may be arranged to be attached, directly or indirectly, to the first end and to the second end of the display. In an example, a first end 2.1 of the first wire is attached to the second frame 5, for example to the display back support 7, and/or a second end 2.2 of the first wire is attached to the first frame 6. Alternatively or additionally, the same may be applied for the second wire. The first wire may be attached to the first frame and/or the second frame by means of tight fitting, welding, gluing or screwing. The same holds for the second wire. The attachment for the two wires may be symmetric. The first wire and/or the second wire may be of steel and/or synthetic fiber material, such as paraaramid fiber material.

The first wire system and/or the second wire system may comprise a rolling element 4, such as a pulley, around which the corresponding wire is routed for the tensioning of the display. As such, the rolling element may be on the axis as described above. The rolling element does not, in itself, be a movable rolling element but it can be a fixed element or a movable element. As a fixed element, it may simply be arranged to only direct the corresponding wire, not to move e.g. by rotation in response to friction induced by the corresponding wire. As a movable element, it may have a bearing allowing it to move, for example by rotation, in response to friction induced by the corresponding wire. The rolling element may comprise a channel, for example provided as a groove, for routing the corresponding wire. The channel may comprise an arc portion for this purpose, for example an arc with a semi-circular portion for routing the corresponding wire. The semi-circular portion allows the corresponding wire to be routed so that it exits from the rolling element in a direction parallel to the direction with which it enters the rolling element, while changing the direction of any tensioning force along the wire to be opposite before and after the rolling element, thereby acting as a pulley.

The first wire system comprises one or more springs, including a first spring 3, for lowering the tension sensitivity of the first wire to the length of the first wire. The first spring may be arranged to facilitate maintaining the first wire 2 in constant tension during the stationary state and/or the moving state of the display 1. The second wire system comprises one or more springs, including a second spring 13, for lowering the tension sensitivity of the second wire to the length of the second wire. The second spring may be arranged to facilitate maintaining the second wire 2 in constant tension during the stationary state and/or the moving state of the display 1. Each spring may be arranged at an end of the corresponding wire or along the length of the corresponding wire.

In particular, the first spring and/or the second spring may be a cantilever spring or a coil spring. As a cantilever spring, the first spring and/or the second spring may be positioned lying against one of the frames, e.g. the second frame, in a second direction 11. The second direction may thus be in a plane of the surface of the corresponding frame. This facilitates a compact solution. To improve efficiency and force control, the second direction may be substantially perpendicular with respect to the first direction. A width, such as a maximum width, of the cantilever spring in the first direction may be larger than a depth of the cantilever spring in a depth direction. The depth direction may be defined as perpendicular to the first direction and the second direction, e.g. as a thickness dimension of the apparatus. The cantilever spring may have a high spring constant and/or displacement. The first spring 3 and/or the second spring 13 may comprise the rolling element 4, such as a pulley, for example at the end of the corresponding spring. The first wire and/or the second wire may be routed around the corresponding rolling element, for example at a cantilever spring, e.g. at an end thereof.

Fig. 2 illustrates a close-up view of an apparatus 100 according to an example. The apparatus may be in accordance with any of the examples described herein.

In an embodiment, any or all of the wire systems, such as the first wire system and/or the second wire system, may each comprise two or more springs, for example at opposite ends of the corresponding wire. These may include a cantilever spring and a coil spring in the same wire system, for example at the opposite ends of the corresponding wire. In particular, the first wire system and/or the second wire system may each comprise an additional spring 9 such as a coil spring. It may be attached to the first frame or the second frame for the lowering of the tension sensitivity of the corresponding wire to the length of said wire. The apparatus may thus comprise a first movable wire clamp 8 for attaching the first wire to the corresponding frame and/or a second movable wire clamp for attaching the second wire to the corresponding frame. The additional spring can be arranged to cushion the movement of the corresponding wire clamp, for example in the first direction. In a specific embodiment, a wire system comprises a first spring which is a cantilever spring, for example at a first end of the corresponding wire, and a second spring which is a coil spring, for example at a second end of the corresponding wire. The first and/or the second wire system may be as said wire system and the system may include any or all additional features as described above, such as the movable fire clamp for attaching the corresponding wire to the corresponding frame.

As illustrated, any or all of the wires, such as the first wire 2 may be fixed to the display back support 7, for example at a first end 2.1 of the wire. The wire(s) may be stretched around the rolling element 4, such as the pulley of a cantilever spring 3, for the tensioning. The second end of the wire 2.2 may be fixed to, for example, to the wire Clamp 8. A coil spring 9 may be mounted between the wire clamp 8 and the fixed frame 6. Wire system(s) with spring load at both ends of the corresponding wires may be utilized for any solution described herein for keeping the display 1 tensioned during the moving state and/or the stationary state. Fig. 3 illustrates a detail-level view of an apparatus 100 according to an example. The apparatus may be in accordance with any of the examples described herein.

As illustrated, any or all of the wires, such as the first wire 2 may have one end, such as the first end 2.1, being attached to display back support 7. The wire may be attached at a back side of the apparatus. Regardless of where they are attached, the wire(s) 2 may be stretched around the rolling element 4, such as the pulley of a cantilever spring, for the tensioning. The rolling element may be positioned at a free end of a spring 3 such as the first spring, in particular a cantilever spring. The other end the spring 3 may be attached to a frame, in particular to the sliding frame, e.g. the second frame 5, for example by means of tight fitting, welding, gluing or screwing.

Fig. 4 illustrates another detail-level view of an apparatus 100 according to an example. The apparatus may be in accordance with any of the examples described herein. An end, such as the second end 2.2., of the first wire and/or the second wire may be attached to the wire clamp 8. The first frame and/or the second frame, in particular the fixed frame, e.g. the first frame 6, may have such a wire clamp attached thereto, for example by a fixed attachment. Wire clamp 8 can also be spring loaded with a spring 9, such as the coil spring. The spring may be arranged between the wire clamp 8 and the corresponding frame, in particular the fixed frame, e.g. the first frame 6.

Fig. 5 illustrates yet another detail-level view of an apparatus 100 according to an example. The apparatus may be in accordance with any of the examples described herein.

As illustrated, the apparatus may be arranged so that when the display is moved from the open position to the closed position, the first and/or second spring, such as the cantilever spring 3, e.g. with the rolling element 4, is moving with the corresponding frame, in particular the sliding frame, e.g. the second frame 5, and thus pulling the corresponding wire(s), such as the first wire 2 and/or the second wire 12 (not illustrated) for the display to be tensioned in the closed position. The corresponding wire(s) may be attached to the display back support 7.

In general, the first wire system may be symmetric with respect to the second wire system. The positioning of the first wire system with respect to the second wire system and the first and the second frame may be symmetric. The components, such as the wire(s) and/or spring(s), of the first wire system may be symmetric. This allows reliable and effective balancing of the tensioning with the first and the second wire system.

The apparatus 100 may comprise one or more additional wire systems for tensioning the display upon movement of the second frame with respect to the first frame, for example between the first wire system and the second wire system. The one or more additional wire systems may comprise one or more additional wires for this purpose and they may be arranged to be parallel with the first wire and/or the second wire for tensioning the display. In an embodiment, an additional wire system is arranged symmetrically in the middle of the first and the second wire system with a wire parallel with the first wire and the second wire. What is said here regarding the first wire system and/or the second wire system, or the wire(s) thereof, may be applied also to the additional wire system(s) and the wire(s) thereof. In an embodiment, the apparatus comprises four or more wire system for tensioning the display upon movement of the second frame with respect to the first frame, where the number of said wire systems is even. An even number can allow improved balancing in various applications.

As a result, two or more wire systems can be used to prevent compression and bending of the display when the apparatus/display is moved for the open position to the closed position. They can also be used to prevent the display from creasing close to the axis, such as a rolling edge of the apparatus, when the device is in a static position, which can be an open position or a closed position. For any of these purposes, for two or more wire systems, a spring can be attached to one or both ends of a wire arranged for tensioning of the display of each of the two or more wire systems to facilitate balancing forces between said wire systems.

Fig. 6 illustrates a method 600 of tensioning a rollably extending display, for example for the apparatus 100 as described herein. The method may comprise lowering 610 the tension sensitivity of a first wire to the length of the first wire with a first spring. The method may comprise lowering 620 the tension sensitivity of a second wire to the length of the second wire with a second spring. The method may comprise tensioning 630 a first side of the display upon extension of the display with the first wire and tensioning a second side of the display upon extension of the display with the second wire. Any range or device value given herein may be extended or altered without losing the effect sought. Also, any embodiment may be combined with another embodiment unless explicitly disallowed.

Although the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims.

It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to 'an' item may refer to one or more of those items.

The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the embodiments described above may be combined with aspects of any of the other embodiments described to form further embodiments without losing the effect sought.

The term 'comprising' is used herein to mean including the method, blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this specification.

Claims

1. An apparatus comprising:

- a rollably extending display (1) comprising a first end and a second end;

- a first frame (6) attached to the first end of the display;

- a second frame (5) attached to the second end of the display, the second frame being movable with respect to the first frame in a first direction (10) for extending a viewing area of the display;

- a first wire system comprising a first wire (2) for tensioning a first side of the display upon movement of the second frame with respect to the first frame; and

- a second wire system comprising a second wire (12) for tensioning a second side of the display upon movement of the second frame with respect to the first frame; wherein the first wire system comprises a first spring (3) for lowering the tension sensitivity of the first wire to the length of the first wire and the second wire system comprises a second spring (13) for lowering the tension sensitivity of the second wire to the length of the second wire.

2. The apparatus according to claim 1, wherein the first spring is a cantilever spring.

3. The apparatus according to claim 2, wherein the cantilever spring is positioned lying on the second frame in a second direction (11).

4. The apparatus according to claim 3, wherein the second direction is perpendicular with respect to the first direction.

5. The apparatus according to claim 3 or 4, wherein a width of the cantilever spring in the first direction is larger than a depth of the cantilever spring in a depth direction perpendicular to the first direction and the second direction.

6. The apparatus according to any of claims 2-5, wherein the first wire is routed around an end of the cantilever spring.

7. The apparatus according to any of the preceding claims, wherein the first wire and/or the second wire is tensioned from the first end of the display in parallel with the first direction.

8. The apparatus according to any of the preceding claims, wherein the first wire and/or the second wire is tensioned from the second end of the display in parallel with the first direction.

9. The apparatus according to any of the preceding claims, wherein the first wire system comprises an additional spring (9) attached to the first frame for the lowering of the tension sensitivity.

10. The apparatus according to claim 9, wherein the additional spring is a coil spring.

11. The apparatus according to claim 9 or 10, comprising a movable wire clamp (8) for attaching the first wire to the first frame, wherein the additional spring is arranged to cushion the movement of the wire clamp.

12. The apparatus according to claim 11, where the additional spring is arranged to cushion the movement of the wire clamp in the first direction.

13. The apparatus according to any of the preceding claims, wherein the first wire system is symmetric with respect to the second wire system.

14. The apparatus according to any of the preceding claims, wherein the apparatus is a mobile phone.

15. A method (600) of tensioning a rollably extending display, the method comprising:

- lowering (610) the tension sensitivity of a first wire to the length of the first wire with a first spring;

- lowering (620) the tension sensitivity of a second wire to the length of the second wire with a second spring; and - tensioning (630) a first side of the display upon extension of the display with the first wire and tensioning a second side of the display upon extension of the display with the second wire.