Field of the invention

The present disclosure relates to a screen structure.

Background

Bistable extendable members, also referred to as “bistable reeled composites” (BRCs) and/or “split tube extendable members” (“STEMs”) and/or “split tubes” and/or “extendible sheet members” and/or “bistable composite elements”, are elements which are configurable between two stable forms: a rigid longitudinally extending structure, and a compact coil of flat rolled up material. In the compact coiled/rolled up form, a bistable extendable member can be rolled up/wound/coiled about a first axis. In the rigid longitudinally extending form, the bistable extendable member longitudinally extends straight along a second axis which is perpendicular to the first axis.

Bistability in a bistable extendable member arises as a result of the manipulation of the Poisson’s ratio and isotropy in the various layers of material making up the bistable extendable member. Bistable extendable members can be made from fibre-reinforced composite materials, for example glass fibres in a thermoplastic matrix, which are consolidated under conditions of elevated temperature and pressure.

Due to their mechanical properties of being extendable and retractable again into a rolled- up state, bistable extendable members can be useful in retractable structures such as retractable panels, screens, walls, dividers and/or partitions, such as those described in WO2019201948A1 and EP3251562B1.

W08808620 describes an elongate element in the form of a longitudinally split tube. US6217975B1 describes an extendable sheet member which is configurable between first and second states. US6602574B1 describes an extendible, coilable member which is reversibly configurable between a coiled form and an extended form. WO9962811 describes a compound member formed from at least two extendible, coilable members, each of which is reversibly configurable between a coiled form and an extended form. US6256938B1 describes an elongate element in the form of a longitudinally split tube which is arranged to be progressively flattened and wound about an axis extending transversely to the longitudinal extent of the tube to form a coil.

Summary of the invention

Aspects of the invention are as set out in the independent claims and optional features are set out in the dependent claims. Aspects of the invention may be provided in conjunction with each other and features of one aspect may be applied to other aspects.

In a first aspect there is provided a screen structure, for example for deployment over a surface such as a floor. The screen structure comprises at least one support element and a panel element attached to the at least one support element. The at least one support element and the panel element are configured to be rollable about a longitudinal axis, to provide for extension and retraction thereof along a direction generally perpendicular to the longitudinal axis. The panel element comprises a rollable switchable opacity film whereby the opacity of the film can be controlled to vary the opacity of the panel. The support element may comprise a bistable extendable member.

The switchable opacity film may comprise a liquid crystal material.

The opacity of the film may be controlled by applying a voltage to the film.

The switchable opacity film may occupy substantially the entirety of the panel element.

The switchable opacity film may be sandwiched between two layers of fire-retardant material, optionally with a fire-retardant material (such as a fire-retardant strip) bounding the switchable opacity film between the two layers of fire-retardant material.

The fire-retardant material may comprise, for example, polyvinylchloride (PVC), polyvinylflouride (PVF) or a polyester film such as Melinex®.

The switchable opacity film may comprise a layer of adhesive between each layer of fire- retardant material. The layer of adhesive may optionally be equal to or less than 50 pm thick, preferably equal to or less than 25 pm thick. This may advantageously improve the optical qualities of the panel. The screen structure may further comprise a rotor coupled to the at least one support element and the panel, the rotor configured to rotate about a longitudinal axis. In some examples the screen structure comprises a spine element to provide structure rigidity to the screen structure. In some examples the spine element may be in the form of a housing configured to at least partially enclose the rotor and a portion of the panel element and at least one support element. The at least one support element and the panel element are configured to be rollable about the rotor about the longitudinal axis inside the housing, to provide for extension and retraction thereof along a direction generally perpendicular to the first longitudinal axis to and from the housing.

In some examples the screen structure further comprises a slip ring, wherein the slip ring comprises a first portion coupled to the rotor and a second portion coupled to the housing, and wherein the first portion and second portion are configured to rotate relative to each other and to provide an electrical coupling between a power source and the switchable opacity film.

In another aspect there is provided a screen structure for deployment, for example over a surface such as a floor. The screen structure comprises at least one support element, a panel element attached to the at least one support element, and a rotor coupled to the at least one support element and the panel, the rotor configured to rotate about a longitudinal axis. The screen structure may also comprise an optional housing. The housing may be configured to act as a support structure, such as a spine, and in some examples may be configured to at least partially enclose the rotor, and optionally a portion of the panel element and at least one support element. The at least one support element and the panel element are configured to be rollable about the rotor about the first longitudinal axis inside the optional housing, to provide for extension and retraction thereof along a direction generally perpendicular to the longitudinal axis to and from the optional housing. The screen structure further comprises a slip ring, wherein the slip ring comprises a first portion coupled to the rotor and a second portion coupled to the housing or other support structure supporting the screen structure, and wherein the first portion and second portion are configured to provide an electrical coupling between each other and to rotate relative to each other. The at least one support element may comprise a bistable extendable member. The panel element may comprise a rollable switchable opacity film whereby the opacity of the film can be controlled to vary the opacity of the panel, and wherein the slip ring is configured to provide an electrical coupling between a power source and the switchable opacity film.

The first portion of the slip ring may be configured to remain static relative to the rotor, and wherein the second portion of the slip ring is configured to remain static relative to the housing or other support structure supporting the screen structure. The housing or other support structure supporting the screen structure may optionally be configured to remain static to the ground/wall/a supporting structure.

The slip ring may further comprise a first support member coupled to the first portion of the slip ring, and a second support member coupled to the second portion of the slip ring, wherein the first support member and the second support member are supported relative to each via a bearing, and wherein the first support member is coupled to the rotor and the second support member is coupled to the housing or other support structure supporting the screen structure.

The bearing may be configured to rotate about a rotation axis, and wherein the rotation axis is coaxial with the longitudinal axis of the rotor.

The bearing may comprise an annulus about the longitudinal axis and mounted on the second support member, the annulus having an inner housing and an outer housing separated by ball bearings and rotatable relative to each other, the outer housing having a greater diameter than the inner housing. The first support member may comprise a disk comprising a flange, wherein the flange is arranged to contact the outer housing of the bearing to support the first support member and the rotor relative to the second support member and the housing or other support structure supporting the screen structure.

The first support member may be fixedly coupled to the rotor. For example, the first support member may comprise a protrusion arranged to provide a fixed rotation fit, which may be an interference fit, with the rotor, and an aperture for receiving the first portion of the slip ring via an interference fit, wherein the protrusion and the aperture are coaxial with each other and with the longitudinal axis.

The second support member may comprise an upstanding tube portion forming an aperture for receiving the second portion of the slip ring. The second support member may be fixedly coupled to the second portion of the slip ring via a fixed rotation fit such as an interference fit. The inner housing of the bearing annulus may be arranged around the upstanding tube portion forming the aperture of the second support member for receiving the second portion of the slip ring. The inner housing of the bearing annulus may therefore support the outer housing of the bearing annulus (and thereby the first support member and rotor) relative to the second support member.

The slip ring may further comprise a flange coupled to the second portion of the slip ring, wherein the flange is configured to engage at least one of (i) the upstanding tube portion, and (ii) the inner housing of the bearing annulus, to support the slip ring against the second support member.

The first support member may support the rotor relative to and inside the housing or other support structure supporting the screen structure.

The housing may be elongate having a longitudinal axis in the elongate direction and may comprise a first housing flange proximate to an end of the housing along the longitudinal axis, and wherein the second support member may be coupled to the flange inside the housing to support the first support member and the rotor inside the housing.

While the housing may at least partially enclose the panel element and the at least one support element, in other examples the housing may not enclose the panel element, for example the housing may only partially enclose the rotor such as regions at the ends of the rotor to support the rotor and optionally limit and/or inhibit access to bearings and/or the slip ring.

Drawings

Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1A shows a perspective view of a bistable extendable member in a partially rolled up state;

Figure 1 B shows a perspective view of the bistable extendable member of Figure 1A in a fully rolled up state or configuration;

Figure 1C shows a perspective view of the bistable extendable member of Figure 1A in a fully longitudinally extended state or configuration;

Figure 2A shows the cross-sectional profile of the bistable extendable member of Figure 1 A when it is in a rolled up state or configuration, as in Figure 1 B;

Figure 2B shows the cross-sectional profile of the bistable extendable member of Figure 1 A when it is in a longitudinally extended state or configuration, as in Figure 1C;

Figure 3A shows a front view of a screen structure in a fully extended position or configuration;

Figure 3B shows a front view of the screen structure of Figure 3A in a partially extended position or configuration;

Figure 4A shows a rear perspective view of a screen structure in a fully extended position or configuration;

Figure 4B shows a front perspective view of the screen structure of Figure 4B in a partially extended position or configuration;

Figure 5 shows a cross-section of a portion of the screen structure of Figs. 4A and 4B;

Figure 6 shows an enlarged portion of the cross-section of Figure 5;

Figure 7 shows the cross-section of Figure 5 with a panel and bistable extendable members in an extended state or configuration; Figure 8 shows perspective view of the slip ring assembly of Figures 5 and 6;

Figure 9 shows perspective view of the slip ring assembly of Figures 5 and 6;

Figure 10 shows an exploded view of the cross-section of the slip ring assembly of

Figures 5, 6, 8 and 9;

Figure 11 A shows a side view of an example screen structure;

Figure 11 B shows a side view of another example screen structure;

Figure 12 shows a perspective view of another example screen structure; and

Figure 13 shows a cross section of a portion of another example screen structure.

Specific description

Figure 1A illustrates a bistable extendable member 1. The bistable extendable member 1 is configurable in a first state in which the bistable extendable member 1 is rolled up (i.e. coiled) about a first axis 2, and a second state in which the bistable extendable member 1 is longitudinally extended along a second axis 3 which is perpendicular to the first axis 2. As shown in Figure 1A, the bistable extendable member 1 can be in both the first state and the second state at the same time when the bistable member is partially coiled up or extended. For example, a first portion 4 of the bistable extendable member 1 can be in the first coiled state, and simultaneously, a second portion 5 of the bistable extendable member can be in the second extended state, with a transition portion 6 between the first portion 4 and the second portion 5. In the examples discussed herein, the bistable extendable member 1 comprises a bistable composite split tube extendable member. However, it is also to be understood that any other bistable extendable member(s) may be employed, such as a non-composite bistable extendable member, or any other bistable reeled composite or bistable split tube extendable member.

Figure 1 B shows the bistable extendable member 1 when it is fully in the first state. That is, when the entire length of the bistable extendable member 1 is rolled up about the first axis 2. Conversely, Figure 1C shows the bistable extendable member 1 when it is fully in the second state. That is, when the entire length of the bistable extendable member 1 is longitudinally extended along the second axis 3.

As shown in Figure 2A, when the bistable extendable member 1 is in the first state, in a plane which is normal to the second axis 3, the bistable extendable member 1 has a cross- sectional profile 7 which is substantially flat and straight. This is also shown in Figure 1 B. As shown in Figure 2B, when the bistable extendable member 1 is in the second state, in a plane which is normal to the second axis 3, the bistable extendable member 1 has a cross-sectional profile 8 which is C-shaped. That is, when the bistable extendable member 1 is in the second state, it curves upwards at its longitudinal edges. This is also shown in Figures 1A and 1C.

With reference to Figure 1A, the bistable extendable member 1 is selectively configurable between the first state and the second state. The bistable extendable member 1 can be progressively rolled up by applying a rolling force FR to the first portion 4 to cause an increase in the length of the bistable extendable member 1 which is rolled up to form the first portion 4 and conversely a decrease in the length of the bistable extendable member 1 which is extended to form the second portion 5. Conversely, the bistable extendable member 1 can be progressively longitudinally extended by applying an extending force FE to the first portion 4 to cause an increase in the length of the bistable extendable member 1 which is extended to form the second portion 5 and a decrease in the length of the bistable extendable member 1 which is rolled up to form the first portion 4.

With reference to Figure 1 B, when the bistable extendable member 1 is fully in the first state, i.e., when it is fully rolled up, a pulling force FP can be applied to the outwardly facing end 9 of the bistable extendable member 1 in order to initiate the longitudinal extension of the bistable extendable member 1 to form the second portion 5. The extending force FE can then be applied as in Figure 1A to increase the length of the bistable extendable member 1 which is extended to form the second portion 5, as desired. Similarly, as shown in Figure 1 C, when the bistable extendable member 1 is fully in the second state, i.e., when it is fully longitudinally extended, a coiling force, FC, can be applied to the end 9 of the bistable extendable member 1 to initiate the rolling up of the bistable extendable member 1 to start forming the first portion 4. An exemplary application of the bistable extendable member 1 described herein shall now be described, with reference to Figures 3A and 3B, which show an exemplary screen structure 47.

In the screen structure 47, a first bistable extendable member 1a and a second bistable extendable member 1 b (which may hereinafter be referred to collectively as “bistable extendable members 1”) are employed as upper and lower members 48a, 48b respectively, of a frame 48. Side members 48c, 48d of the frame 48 are provided by aluminium supports 43a and 43b respectively.

A panel 44 comprising a flexible polymer film (though panels of other materials such as other polymers and/or textiles may also be employed) is arranged to hang substantially flat in the plane defined by the frame 48 and may be attached to the upper and lower members 48a, 48b directly, for example via welding, or for example, via a detachable fastening means such as one or more zips.

The panel 44 may comprise a rollable switchable opacity film whereby the opacity of the film can be controlled to vary the opacity or obscurity of the panel. For example, the opacity of the panel can be controlled to vary between two states. It will be understood that when it is described herein that the opacity of the film may be control led/varied this will be understood to mean that the film can switch between being transparent and obscured, such as translucent. However, in other examples it may mean that the film can switch between being transparent and opaque such that it does not permit, or at least inhibits, the transmission of light.

Advantageously this means that the screen can be controlled at the switch of a button to give privacy to a user by turning translucent, for example in scenarios where the screen system may be used to provide a curtain around a patient’s bed in a healthcare setting such as a hospital, but so that the screen can be switched to transparent when a doctor or other healthcare professional wants to talk to the patient so that the doctor and patient can see each other. Advantageously, by having such a switchable opacity film, it means that the screen can remain in place even when the healthcare professional is talking to the patient, thereby minimizing and reducing the potential for infection to occur (e.g., caused by influenza, coronavirus etc.).

For example, the transmission haze of the material may be controlled/varied. For example, controlling or varying the opacity of the film may comprise controlling or varying the haze (i.e. , the amount of light subject to wide angle scattering (at an angle greater than 2.5° from normal (ASTM D1003))) and/or clarity (i.e., the amount of light that is subject to narrow areas scattering (at an angle less than 2.5° from normal). Measurement of these factors is defined in two International test standards: ASTM D1003 and BS EN ISO 13468 Parts 1 and 2. ASTM D1003 comprises two test methods: procedure A - using a Hazemeter, and procedure B - using a Spectrophotometer. BS EN ISO 13468 part 1 - uses a single beam Hazemeter, and part 2 - uses a dual beam Hazemeter.

The switchable opacity film may comprise a liquid crystal material, for example a film obtained from Ambio Film 2F.-4,No.8, Fujin St., Songshan Dist., Songshan District 105 Taipei City, Taiwan. For example, the liquid crystal material may comprise E7 and E8 liquid crystal blends and PM MA, PVA or PVB as polymers.

The opacity of the film can be controlled by applying a voltage to the film, for example a switching voltage of less than or equal to 240VAC, preferably less than or equal to 50 VAC. For example, the rollable switchable opacity film may be configured to remain in a first state (e.g., translucent) when no voltage is applied, and in a second state (e.g., transparent) when the voltage is applied.

The rollable switchable opacity film may have a haze of less than or equal to 5% in the second transparent state and may require a temperature of between 60 and 95°C to clear. For example, the degree of opacity (haze) in the first (translucent or “power off’) state may be >95, and a degree of opacity (haze) in the second (transparent or “power on” state may be <6.

In the examples shown, the switchable opacity film occupies substantially the entirety of the panel element, although it will be understood that in other examples the switchable opacity film may only occupy a region or a portion of the panel element, for example half of the panel element, for example a lower half of the panel element. The switchable opacity film may have a thickness of less than 1 mm, for example less than 0.5mm, for example, 0.4mm.

The panel 44 may be laminated. The switchable opacity film is sandwiched between two layers of fire-retardant material. The fire-retardant material may comprise a polymer or blend of polymers, such as polyvinylchloride (PVC), Kedlar® (commonly known as polyvinyl fluoride (PVF)), or Melinex® (which is a type of polyester (PET)). There may be layer of adhesive between each layer of fire-retardant material, but in some examples the layers may be electrostatically coupled together, for example. Each layer of adhesive is optionally equal to or less than 50 pm thick, preferably equal to or less than 25 pm thick.

The fire-retardant material may be in the form of a film with a thickness of 75-175 microns (300-700 gauge). The film may be pre-treated on one side (as is FR321) to promote adhesion. The adhesive used may be an optically clear adhesive (e.g. CEF08XX (821X/818X) Series) and may have a thickness of between 25pm and 175pm.

The fire-retardant material may be a DigiSOL DS3054 P ultra-clear monomeric film and/or may comprise DuPont Teijin Films™ Melinex® FR320/FR321 clear, flame retardant polyester film, which is a halogen-free, low haze VTM-0 PET polyester film. It is ANSI/UL 94 certified VTM-0 flame rating for “Tests for Flammability of Plastic Materials for Parts in Devices and Appliances”.

In some examples the panel 44 may comprise fire-retardant material, such as a fire- retardant strip, around its edge. For example, a fire-retardant strip may encircle or envelop the switchable opacity film (for example such that it bounds the switchable opacity film) and be contained within the laminations of the material, such that the fire-retardant strip is contained between the two layers of fire-retardant materials, bounding the switchable opacity film. In some examples, the-fire retardant strip may be an intumescent strip. Additionally, or alternatively the fire-retardant strip may be a fire-retardant rope and/or a fire-retardant tape such as aluminium tape. Additionally, or alternatively, fire retardant material may be provided over the edges of the lamination, optionally over all of the edges of the lamination such that the fire-retardant material (for example, aluminium tape) bounds the entire panel 44.

The aluminium supports 43a and 43b are each attached to a respective base element 45a, 45b. Supports 43a and 43b and base element 45a, 45b are at least on their own light enough for a user to pick up and move (‘pick and place’) them around, making the structure

47 highly portable and independently movable. One or more handles and/or knobs and/or other protruding elements may be attached to the support 43a or 43b and arranged to protrude therefrom, to make it easier for a user of the screen structure 47 to grip and hold the supports 43a or 43b, to improve the ergonomics of the screen structure 47. A knob 38 is shown on support 43a and could equally be applied to support 43b.

By means of the two states of the bistable extendable members 1a and 1 b, the frame 48 and thus also the panel 44 can be progressively rolled up or extended, due to the bistable properties of the bistable extendable members 1a and 1 b, as described above in relation to the bistable extendable member 1 . Figure 3A shows the structure 47 and thus the panel 44 in a fully extended position wherein the bistable extendable members 1a, 1b are fully longitudinally extended, as in Figure 1C. Figure 3B shows the structure 47 and thus the panel 44 in a partially extended position wherein the bistable extendable members 1a, 1b are partially longitudinally extended, as in Figure 1 A. Once lifted, a pushing or pulling force can be applied to the support 43a or support 43b to cause the frame 48 and the panel 44 to be retracted/rolled up/closed or extended/pulled out/opened respectively. The supports 43a and/or 43b as described herein may be referred to as being ‘handle elements’ in so far as, amongst other things, they function to allow a user to extend and retract the frame

48 and panel 44 once they have been picked one up, moved it and placed it on the ground in another location so as to extend or retract the frame (i.e. the supports 43a and/or 43b allow a user to extend or retract the frame 48 and panel 44 upon application of a force thereto).

In the example shown in Figures 3A and 3B, the supports 43a, 43b are sized and shaped such that when the structure 47 and the panel 44 are in a substantially fully retracted position (not shown), the supports 43a, 43b will abut one another. Thus, the geometry of the supports 43a, 43b provides that the support 43a may only be positioned and orientated relative to the support 43b in one particular position and orientation, which may be designed to be a desired position and orientation which leaves a leading end portion of the bistable extendable members 1a, 1 b slightly extended, to avoid mechanical fastenings (not shown) which attach the leading end of each of the bistable extendable members 1 to the support 43a, from rubbing on the coiled portion 4 (see Figure 1 A) of the bistable extendable members 1 , thus reducing the likelihood of damage to the bistable extendable members 1.

Figures 4A and 4B show an alternative exemplary screen structure 15 which is mounted to a generally vertical wall 17. It is though envisaged that the screen structure 15 may be mounted to any other surface, such as a generally vertical post, or a piece of furniture. Alternatively, it is also envisaged that the screen structure 15 may be adapted to be freestanding, i.e. , not mounted to a surface such as a wall.

The screen structure 15 is generally similar to the screen structure 47 shown in Figures 3A and 3B, in that it comprises bistable extendable members 1a and 1 b, and a panel 44. As with the example of Figures 3A and 3B, the panel 44 may comprise a switchable opacity film, optionally sandwiched between two layers of fire-retardant material.

Though, instead of aluminium supports 43a and 43b (as in Figures 3A and 3B), an elongate handle element 14 and a housing which in this example is in the form of a spine element 16 form a frame 18 together with the bistable extendable members 1a, 1 b, inside which the panel 44 is arranged. The elongate handle element 14 and the spine element 16 may be formed of aluminium, or any other suitable metal or other material(s). In the example described herein, the bistable extendable members 1a, 1 b comprise bistable composite split tube extendable members, though it is envisaged that any other bistable extendable members may be employed. The handle element 14 is attached to a base element 45.

In the example shown, the spine element 16 comprises a generally straight elongate member having a generally rectangular cross-sectional profile. The spine element 16 is arranged to provide structural support and stiffness to the screen structure 15. Similarly, in the example shown, the handle element 14 comprises a generally straight elongate member having a generally square cross-sectional profile. A pushing or pulling force can be applied to the handle element 14 to cause the bistable extendable members 1a, 1 b and the panel 44 to be retracted/rolled up/closed or extended/pulled out/opened respectively about a first longitudinal axis 19.

The spine element 16 may be formed from an aluminium extrusion, for ease of manufacture and assembly. One or more handles and/or knobs and/or other protruding elements may be attached to the handle element 14 and arranged to protrude therefrom, to make it easier for a user of the screen structure 15 to grip and hold the handle element

14, to improve the ergonomics of the screen structure 15.

It is also envisaged that alternative shapes, sizes and configurations of handle elements and spine elements may alternatively be employed in the screen structure 15 other than those which are shown in Figures 4A and 4B and described below.

Figure 5 shows a cross-section of a portion of the screen structure 15 of Figs. 4A and 4B, and Figure 7 shows the cross-section of Figure 5 with a panel 44 and bistable extendable members 1 a and 1 b in an extended configuration. Figures 5 and 7 show the spine element 16 which in this example is formed from an aluminium extrusion fixed to a wall 17 via two hinges 500A, 500B. The spine element 16 in this example may provide a housing 550, and is coupled to a rotor 552 configured to rotate in the housing 550, although it will be understood that in other examples the housing 550 may not be necessary, and that only the spine element 16 may be used, for example, to provide structural rigidity to the screen structure 15 and/or that the housing 550 may only cover portions of the screen structure

15, such as the ends of the rotor 552 for example to prevent access to the bearings and moving parts contained therein. The rotor 552 is elongate along the longitudinal axis 19 (as shown in Figs. 4A and 4B) and comprises a biasing means such as a spring 555, such as a round spring loaded conveyor roller (of the type commonly found in roller blinds) to provide tension to the rotor 552 and thereby facilitate extension and retraction of the panel 44 and bistable extendable members 1a and 1 b. The rotor 552 is hollow and the spring 555 is located inside the rotor 552.

In the example shown, the rotor 552 is configured to rotate within housing 550, however as noted above in other examples the spine element 16 may not form a housing 550; in such examples the rotor 552 may be configured to rotate relative to the spine element 16 and any fixing means such as hinges 500A, 500B used to secure the screen structure 15 in place. In this example, the housing 550 is also formed from an aluminium extrusion (although it will be appreciated that the housing 550 may be formed from other materials using other techniques known to the skilled person), and is configured to house both the rotor 552, the panel 44 and bistable extendable members 1a and 1 b when they are rolled onto the rotor 552 from the extended configuration shown in Figure 7. The housing 550 is therefore elongate along the longitudinal axis 19 to at least partially enclose the rotor 552, the panel 44 and bistable extendable members 1a and 1 b when they are rolled onto the rotor 552. The housing 550 has an aperture to allow the panel 44 and bistable extendable members 1a and 1 b in and out of the housing 550. The aperture is therefore elongate along the longitudinal axis 19 and is in the form of a slit (not shown in Figure 5). The handle element 14 may be configured to be received by the aperture such that the handle element 14 blocks the aperture and also to prevent any further retraction of the panel 44 onto the rotor 552, as shown in Figure 11 .

The hinges 500A, 500B in the example shown are at opposing ends of the housing along the longitudinal axis 19 to support the housing 550 from the wall 17. The housing 550 also comprises a first flange 551 at a proximal end of the housing 550 and a second flange 552 at a distal end of the housing 550. The rotor 552 is configured to couple to each of the first flange 551 and second flange 552 to rotatably support the rotor 552 in the housing 550.

In this example the panel 44 comprises a switchable opacity material. The switchable opacity material is configured to alter its opacity via the application of a voltage. The panel 44 therefore needs to be electrically coupled to a power supply, yet whilst still being rollable about rotor 552. Accordingly, as can be seen more clearly in Figure 6 and as described in more detail below with reference to Figures 8 to 10, there is a slip ring assembly 560 at a proximal end of the housing 550, configured to both provide a bearing for the rotor 550 and to electrically couple the panel 44 to a power supply.

Figure 6 shows an enlarged portion of the cross-section of Figure 5. Figures 8 and 9 shows perspective view of the slip ring assembly 560 of Figures 5 and 6. As can be seen in more detail, the slip ring assembly 560 comprises a slip ring 570 mounted inside a support 577. The support 577 comprises a first support member 575 coupled to the rotor 544 and a second support member 576 mounted on the first flange 551 of the housing 550. Between the first support member 575 and the second support member 576 is a bearing 579. The bearing 579 is toroidal and comprises an annulus about the longitudinal axis 19 and is mounted on the second support member 576.

The slip ring assembly may be a 6 wire 2A slip ring, for example available from SparkFun Electronics®. Each Slip ring may be capable of handling a continuous working speed of 250RPM, a current rating of 2A, and an operating voltage of 210VDC / 240VAC. It has an outer diameter of 22mm for the body and a 44.5mm diameter flange. It has 250mm stranded wires protruding from each side of the slip ring that have a thickness of 28AWG. The whole assembly may have a water protection rating of IP51 .

As can be seen in more detail in Figure 10, which is an exploded view of the cross-section of the slip ring assembly 560 of Figures 5, 6, 8 and 9, the slip ring 570 comprises a first portion 572 configured to remain static relative to the rotor 552, and a second portion 571 configured to remain static relative to the housing 550. The bearing 579 is configured to rotate about a rotation axis, and wherein the rotation axis is coaxial with the longitudinal axis 19 of the rotor 552.

The bearing annulus 579 has an inner housing 581 and an outer housing 580 separated by ball bearings (not shown). The inner housing 581 and the outer housing 580 are rotatable relative to each other, the outer housing 580 having a greater diameter than the inner housing 581.

The first support member 575 supports the rotor 552 relative to and inside the housing 550. In the example shown, the first support member 575 is in the form of a flattened circular disk having the profile of a frisbee with a curved lip forming a flange 585 around the periphery of the disk. The flange 585 has a stepped internal profile that is arranged to contact the outer housing 580 of the bearing 579 both on top of the outer housing 580 (in the longitudinal axis 19) and around a portion of the outer housing 580 (in a radial direction) to support the first support member 575 and the rotor 552 relative to the second support member 576 and the housing 550. Furthermore, the stepped profile of the curved lip forming the flange 585 secures the first support member 575 onto the bearing 579 to prevent any lateral movement (relative to the longitudinal axis 19) of the first support member 575 and thereby the rotor 552 relative to both the bearing 570 and the second support member 576. In the example shown the second support member 576 also has a stepped profile (e.g., relative to the profile of the first flange 551 of the housing 550) so that the second support member 576 only supports the inner housing 581 of the bearing 579 and does not contact the outer housing 580 of the bearing 579, to thereby facilitate relative movement of the bearing 579. The first support member 575 further comprises a protrusion 544 arranged to fixedly couple the first support member 575 to the rotor 552, and in this example the protrusion 544 is arranged to provide an interference fit with the inside of the hollow rotor 552. The first support member 575 may also be fixedly coupled to the slip ring 570, and in this example also comprises an aperture 545 for receiving the first portion 572 of the slip ring 570 via an interference fit. The protrusion 544 may be hollow (i.e., tubular) to reduce weight. The protrusion 544 and the aperture 545 are coaxial with each other and with the longitudinal axis 19. As shown in Figures 8 and 9, the protrusion 544 may comprise ribs around the periphery of the protrusion 544 to improve and provide a keyed interference fit with the inside of the rotor 552 to fixedly coupled the first support member 575 to the rotor 552. The ribs may be configured to key with or be received by corresponding recesses inside the rotor 552 to ensure that the first support remember 575 remains static relative to the rotor 552.

The second support member 576 comprises an upstanding tube portion 578 forming an aperture 574 for receiving the second portion 571 of the slip ring 570. The second support member 576 is fixedly coupled to the second portion 571 of the slip ring 570, in this example via an interference fit. The inner housing 581 of the bearing 579 is arranged around the upstanding tube portion 578 forming the aperture 574 of the second support member 576 for receiving the second portion 571 of the slip ring 570. In this way, the inner housing 581 of the bearing 579 supports the outer housing 580 of the bearing 579 (and thereby the first support member 575 and rotor 552) relative to the second support member 576.

The slip ring 570 further comprises a flange 573 coupled to the second portion 571 of the slip ring 570. The flange 573 is in the form of a circular disk and is configured to engage at least one of (i) the upstanding tube portion 578, and (ii) the inner housing 581 of the bearing annulus 579, to support the slip ring 570 against the second support member 576. In the example shown, the upstanding tube portion 578 is shorter in the longitudinal axis than the bearing annulus 579 so that the flange 573 engages with the inner housing 581 of the bearing annulus 579 to support the slip ring 570.

As noted above, the switchable opacity film of the panel 44 may be switchable upon the application of a voltage to the film. Accordingly, in some examples a power module comprising a transformer may be needed to control the opacity of the panel 44. Placement of the power module may need to be carefully considered to ensure that it does not inhibit use of the screen structure. Figures 11 to 13 show different example embodiments of the screen structure indicating different placements of the power module 1000. As can be seen in Figure 11 A, in this example the power module 1000 may be placed on top of the housing 550 such that it rests, for example, on the top of the second flange 552. A cable or wire may run from the power module 1000 down the length of the housing to the slip ring assembly 560 to provide power/to control the switchable opacity of the panel 44. Additionally, or alternatively, while the slip ring assembly 560 is shown as being at the bottom (proximal) end of the housing 550, it will be understood that in other examples the slip ring assembly may additionally or alternatively be at the other (distal) end of the housing 550.

In the example of Figure 11 B, the power module 1000 is coupled to the wall 17, for example behind the housing 550 so as to be at least partially obscured for aesthetic reasons. A cable may run from the power module down the wall and through one of the hinges (e.g., hinge 500B) to the slip ring assembly 560.

Figure 12 shows a profile view of another example embodiment, in this case similar to the example of Figures 3A and 3B. In this example rather than a flat base elements 45a, 45b, in this example the base elements 45a, 45b are rollable and accordingly may comprise castors or wheels to aid in deployment of the screen structure. In this example the screen structure may comprise two power modules, 1000A and 1000B, both mounted to the rollable base elements 45a, 45b.

In the example shown in Figure 13, the power module 1000 is coupled to the underside of the first flange 551 adjacent to but on the opposite side from the slip ring assembly 560. This may provide the most direct connection between the power module 1000 and the panel 44 and thereby reduce the need for cables/wires to be distributed about the housing 550 thereby reducing the risk that they may get caught up in the panel 44 and/or the rotor 552.

Additionally, or alternatively, it will be appreciated that the power module 1000 may be integrated into the slip ring assembly 560. For example, the power module 1000 may comprise a toroidal transformer that has approximately the same dimensions as the bearing 579 which may also be toroidal. Both the power module 1000 and the bearing 579 may therefore have a central hole or cavity in their middle. The power module 1000 may be mounted underneath the bearing 579 such that the bearing 579 rests on the power module 1000. For example, the upstanding tube portion 578 of the second support member 576 may be configured to be inserted inside the central hole or cavity of both the power module 1000 and the bearing 579 to support both the power module 1000 and the bearing 579 and prevent any lateral movement of both the power module 1000 and the bearing 579 relative to the longitudinal axis 19. The power module 1000 may therefore support the bearing 579 on the second support member 576. In some examples the power module 1000 may either have a stepped profile or have a slightly smaller diameter than the bearing so that the power module 1000 only supports the inner housing 581 of the bearing 579 and does not contact the outer housing 580 of the bearing 579, to thereby facilitate relative movement of the bearing 579.

It will be appreciated from the discussion above that the embodiments shown in the Figures are merely exemplary, and include features which may be generalised, removed or replaced as described herein and as set out in the claims. In the context of the present disclosure other examples and variations of the apparatus and methods described herein will be apparent to a person of skill in the art.