[0001] The present invention relates to a viewing panel unit for mounting in a substantially vertical surface such as door or a wall. More particularly, the present invention relates to a viewing panel unit having means to selectively shield against ionising and/or non - ionising radiation.

Background of the Invention

[0002] Viewing panel units, also referred to as privacy vision panels, are window - like units used in environments wherein privacy for the users of a room is required on an ad hoc basis, and are frequently installed in the doors of consulting room in medical and dental practices. [0003] A typical viewing panel unit includes at least a first fixed panel facing a corridor or thoroughfare outside the room, wherein the first panel has both transparent viewing sections and obscured sections, and a second movable panel facing the room itself, likewise having both transparent viewing sections and obscured sections, wherein the first and second panels are substantially parallel and proximate one another. The prior art viewing panel further includes selective displacement means, typically a knob apt to rotate a cam member located under the second panel via a shaft transverse the panel unit, in order to selectively displace the second panel up and down relative to the first panel, so that the obscured sections of the second panel occlude the transparent viewing sections of the first panel. It is known to provide double - glazed viewing panel units having a third panel, wherein the second movable panel is enclosed between the first and third panels. WO201 1048354 discloses such viewing panel units. [0004] Some solutions have been developed to shield against sources of hazardous ionising or non - ionising radiation, for instance and respectively laser devices of varying wavelengths and radiology appliances of varying power, which are increasingly present at locations dispensing medical or cosmetic treatment, amongst others.

[0005] Conventionally, prior art viewing panel units are installed in a door or wall section of a room, and an external remote shielding solution is used, in the form of a blind, curtain or screen made to order, for instance as manufactured by Kenex® in England. The blind is mounted to the door or to the wall in the room, above or adjacent the viewing panel unit and, in use, an operator or practitioner must cover the privacy vision panel with the blind before using the radiating device, then stow the blind thereafter. When no shield is present, the operator or practitioner must ensure that bystanders do not inadvertently move near unshielded openings, including viewing panel units, of a treatment room whilst a radiating device is in use, which is highly inconvenient. [0006] Established manufacturers of such viewing panel units, such as

Vistamatic® and Visicom® in England, provide viewing panel units shielded against x-ray or laser radiation, which do not require an external remote shielding solution as discussed above. [0007] For instance, Vistamatic® markets panel units having a panel made of a tinted acrylic material, wherein the tint color shields against laser devices emitting in a particular wavelength. In a similar manner, Visicom markets laser protection solutions for its viewing panel units, in the form of aftermarket color filters, designed to cover the entire face of a viewing panel unit. Vistamatic® also markets panel units having a panel made of glass specially treated with lead material. Each of these solutions permanently obscures at least partially the transparent viewing sections of a viewing panel unit, whether the unit is opened or closed for privacy. Summarv of the Invention

[0008] The present invention shields a viewing panel unit against hazardous ionising and/or non - ionising radiation emitted by adjacent radiating devices, with shielding means located within the viewing panel unit itself.

[0009] According to a first aspect there of the present invention, there is provided a viewing panel unit comprising at least a first and second panels substantially parallel to one another and separated by an interstitial volume, at least the first or second panel having a first pattern of substantially opaque and substantially see-through portions thereon; an intermediary panel located within the interstitial volume, having a second pattern of substantially opaque and substantially see-through portions; selective displacement means to selectively displace the intermediary panel within the interstitial volume relative to the first and second panels, so that the opaque portions of the second pattern may selectively occlude the substantially see-through portions of the first patterns; and shielding means to prevent hazardous ionising and/or non - ionising radiation emitted by a device or appliance adjacent the first or second panel from passing through the viewing panel unit, wherein the shielding means is located within the interstitial volume.

[0010] Preferably, the shielding means comprises the both the first pattern and the second pattern, wherein the first and second patterns are made of a material impervious to hazardous ionising and/or non - ionising radiation emitted by the device or appliance.

[0011] Preferably, dimensions of the respective portions of the first and second patterns differ, so that the first and second patterns overlap, in order to prevent radiation from passing through the substantially see-through portions at an angle.

[0012] Alternatively, the first and second patterns are substantially identical. [0013] The first and second patterns may be machine - cut, laser - cut, water - cut, milled, sintered, moulded or fabricated from sheet material, and securely fastened to each panel.

[0014] In an alternative embodiment, the shielding means comprises a third pattern superimposed both on at least one first pattern and on the second pattern, wherein the third pattern is made of a material impervious to hazardous ionising and/or non - ionising radiation.

[0015] In this embodiment, dimensions of the respective portions of the first, second and third patterns differ, so that the third pattern overlaps at least the first and second patterns, in order to prevent radiation from passing through the substantially see-through portions at an angle. Alternatively, the first, second and third patterns are substantially identical.

[0016] In this embodiment still, the third pattern may be machine - cut, laser - cut, water - cut, milled, sintered, moulded or fabricated from sheet material, and the first and second patterns may be machine - cut, laser - cut, water - cut, milled, sintered, moulded or fabricated from sheet material and respectively secured to the first and second panel, or may alternatively comprise printed, painted, sandblasted, etched, sintered or screen-printed portions of the first and second panel.

[0017] Hazardous ionising radiation may be emitted by such devices or appliances as X-ray crystallography equipment, x-ray microscopes, radiographs, CT scanners, PET scanners, medical & dental x-ray equipment, food sterilisation and irradiation equipment and, generally, any appliance or device emitting substantia! ionising radiation determined as carcinogen. [0018] In such cases, the material impervious to ionising radiation is preferably selected from the group comprising lead and other metals having a density apt to provide sufficient radiation attenuation. [0019] Hazardous non - ionising radiation may be emitted by such devices or appliances as gas lasers, dye lasers, metal-vapour lasers, solid state lasers, semiconductor lasers, free electron lasers and, generally, any appliance or device emitting substantial non - ionising radiation, for instance class 3B or class 4 lasers.

[0020] In such cases, the material impervious to hazardous non - ionising radiation is preferably selected from the group comprising metals, ceramics, polymers and composites. [0021] Preferably, the material impervious to both ionising and non - ionising hazardous radiations is a high density metal alloy.

[0022] The panel unit is a preferably a bonded and substantially hermetical unit.

[0023] The bonded panel unit may further comprise at least one spacing member located between the first and second panel, which is made of a resilient material. The resilient material is preferably selected from the group comprising high density polyethylene (HDPE), polyethylene, polyurethane, polypropylene, acetal, PTFE, nylon and polyetheretherketones (PEEKs).

[0024] Preferably, the selective displacement means comprises a shaft extending between at least one outer surface of the panel and the interstitial volume, the shaft having an actuating member at its first extremity substantially adjacent the at least one panel outer surface, and a cam member at its second extremity within the interstitial volume, wherein the cam is substantially co-planar with the third panel. The actuating member may be a user - operated knob, apt to rotate the cam member in use. Such a user - operated knob is preferably made of 316 grade stainless steel, or from a copper alloy.

[0025] Alternatively, the selective displacement means comprises an electric motor located substantially adjacent or within the interstitial volume, operably connected to a cam member disposed substantially co-planar with the third panel within the interstitial volume, the motor being selectively operated by an actuating member and apt to rotate the cam member in use. The actuating member may be a remote or panel surface - mounted switch.

[0026] Preferably, the selective displacement means are configured to displace the third panel linearly or non-linearly.

[0027] The viewing panel unit preferably further comprises a switching means operably connected to the power supply of adjacent ionising and/or non - ionising radiation source(s).

[0028] Preferably, the switching means is a switch located within the interstitial volume and configured to prevent power supply to the radiation source(s) when the third panel is in a position wherein opaque portions of its second pattern do not occlude the substantially see-through portions of the first patterns.

[0029] Other aspects are as set out in the claims herein.

Brief Description of the Drawings

[0030] For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present invention with reference to the accompanying drawings in which: W

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Figure 1 is a section view of a viewing panel unit according to a first embodiment of the invention.

Figure 2 is a section view of a viewing panel unit according to a second embodiment of the invention.

Figure 3 is a section view of a viewing panel unit according to a further embodiment of the invention, fitted to a door and wherein the intermediary panel is in a first, open position.

Figure 4 is a section view of a viewing panel unit according to a further embodiment of the invention, fitted to a door and wherein the intermediary panel is in a second, closed position. Figure 5 is a section view of a viewing panel unit according to a further embodiment of the invention, fitted to a door and wherein the intermediary panel is in the first, open position.

Figure 6 shows a detail a viewing panel unit according to a further embodiment of the invention, including circuit switching means.

Figure 7 shows elongate spacer members for use in a sealed viewing panel unit according to a further embodiment of the invention. Detailed Description of the Embodiments

[0031] There will now be described by way of example a specific mode contemplated by the inventors. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the description. [0032] With reference to Figure 1 , a viewing panel unit 100 is shown in section according to a first embodiment of the invention. The viewing panel unit 00 comprises first and second panels 101 , 02 which are substantially parallel to one another and maintained apart by spacing means 150, whereby the configuration of the first and second panels 101 , 102 and the spacing means 150 therebetween defines an interstitial volume 10 between the first and second panels 101 , 102. The first and second panels 101 , 102 have substantially identical dimensions and, in the example, have a height of 400 millimetres, a width of 400 millimetres and a section of 6mm.

[0033] In the example, the spacing means 150 is a single frame member located substantially about the periphery of the first and second panels 101 , 102. In an alternative embodiment, shown in Figure 7, the spacing means comprises a plurality of distinct elongate spacer members 150A, 150B, 150C, 150D for disposing adjacent respective edges of the first and second panels 101 , 102. The frame or spacer members 50 are preferably made of high density polyethylene (HOPE), but may be made from any selected from the group comprising polyethylene, polyurethane, polypropylene, acetal, PTFE, nylon and polyetheretherketones (PEEKs).

[0034] The viewing panel unit 100 further comprises a third, intermediary panel 103 which is located within the interstitial volume 110 and substantially parallel to the first and second panels 101 , 102. The third panel 03 has a smaller height of than the first and second panels 101 , 102 and and thinner section of 4 mm.

[0035] Each of the first, second and third panels 101 , 102, 103 is made from a substantially transparent material such as clear glass, polycarbonate or acrylic compound. Example types of glass include blackout glass, security glass, fire - retardant glass, insulated and non-insulated glass, tinted glass suitable for vivariums, antibacterial coated glass, toughened and laminated glass. [0036] Each panel may be made from the same material, for instance for ease of manufacture and unit parts procuring. Alternatively, each of the three panels may be made from a respective material, for instance according to environmental, use and/or cost constraints.

[0037] The third panel 103 is enclosed in the viewing panel unit 100, the interstitial volume 110 of which is configured to allow the third panel 103 to move within its own plane, between the first and second panels 101 , 102. Accordingly, the third panel 103 has a smaller height dimension than the first and second panels 101 , 102, leaving top and bottom portions 1 11 , 1 12 of the interstitial volume 1 0 that are apt to accommodate, respectively, movement of the third panel 103 in use and displacement means located underneath the third panel 103. [0038] The intermediary panel 103 is moved by a cam member 104 relative to the first and second panels 101 , 102. The cam member 104 is substantially planar and located within the under portion 1 2 of the interstitial volume 1 10, substantially underneath and co-planar with the third panel 103. Gravity maintains the lower edge 105 of the third panel 103 at rest on the periphery of the cam member 104. The cam member 04 is fixedly secured to a shaft 106, either along or at a first extremity 106A thereof, wherein the shaft extends transversally across the panel, between the outer surface 107A of the first panel 101 and the outer surface 107B of the first panel 02, thus across the interstitial volume 110. A user - operated knob 108 is fixedly secured to the second extremity 106B of the shaft 106, substantially adjacent the outer surface 107 of the first panel 101 , thus externally to the interstitial volume 1 0. The knob may be manufactured from 316 grade stainless steel or from anti-bacterial copper alloy. [0039] The cam member 104 or at least its periphery is made of a resilient material having a low coefficient of friction, for instance high density polyethylene (HDPE) and is shaped so as to vary a distance, in a plane co-planar with the third panel 103, relative to the main axis of the shaft 106 as it is rotated. In use, rotation of the knob 108 by a user is translated by the shaft 06 into a corresponding rotation of the cam member 104. Rotation of the cam member 104 translates its periphery relative to the lower edge 105 of the third intermediary panel 103, and the low friction ratio between the periphery and the lower edge 105 allows the shape of the cam member to vary the distance of the third panel 103 relative to the main axis of the shaft 106, whereby the third panel 103 is pushed upwards within the top portion 111 of the interstitial volume 1 10, in a direction still substantially parallel to the first and panels 101 , 102.

[0040] At least the first panel 101 is configured with a first pattern 120 of substantially opaque portions 121 and substantially see-through portions 122, on the side of the panel which faces the interstitial volume 1 10. The substantially see-through portions 122 are portions of the panel 101 which are not obscured, masked or covered in any way and may consist simply of discrete portions of the original panel 101.

[0041] The third, intermediary panel 103 is configured with a second pattern 130 of substantially opaque portions 131 and substantially see-through portions 132, on the side of the panel which faces the second panel 102 within the interstitial volume 1 10. The substantially see-through portions 132 are portions of the third panel 103 which are not obscured, masked or covered in any way and, in embodiments wherein the third panel is made of clear glass, polycarbonate or acrylic compound, the substantially see-through portions 132 consist simply of discrete portions the original panel 103.

[0042] In the embodiment of Figure 1 , the first and second patterns 120, 130 have asymmetrical dimensions one relative to the other, wherein the substantially see-through portions 132 of the third panel 103 have a smaller vertical dimensions than the substantially see-through portions 122 of the first panel 03, to ensure partial overlap of the substantially see-through portions 122 of the first panel 103 by the substantially opaque portions 31 of the third panel 103.

[0043] The substantially opaque portions are oblong bands 121 , 31 cut from sheet material suitable for shielding hazardous ionising and/or non - ionising radiation, or cut into the sheet material forming a pattern support. The material is for instance mild steel, opaque vinyl or carbon fiber and the pattern has a depth of 1 millimeter or less. The bands 121 , 131 extend across a substantial portion of the width of each panel 101 , 02 and are disposed parallel to one another at regular intervals, wherein the said intervals constitute the substantially see-through portions 122, 132 of each pattern 120, 130.

[0044] Both patterns or pattern supports 120, 130 are secured to the respective panel faces with suitable bonding means, in transverse alignment with one another. That is, the first and second patterns 120, 130 are applied to their respective panel 101 , 103 wherein the substantially opaque portions 121 and the substantially see-through portions 122 of the first pattern 120 on the first panel 01 are transversally aligned with corresponding substantially opaque portions 131 and substantially see-through portions 132 of the second pattern 130 on the intermediary panel 103, when the intermediary panel 103 is at its lowest position within the interstitial volume 10. In this position, a user on one side of the viewing panel unit 00 may observe events on the other side of the viewing panel unit 100 through the aligned see-through portions 122, 132 of the first and second pattern 120, 130.

[0045] When the user actuates the cam member 04 via the knob 08, the intermediary panel 03 is displaced relative to the first and second panels 101 , 102, whereby the bands 121 of the second pattern of the intermediary panel 103 eventually occlude the substantially see-through portions 122 of the first pattern 102, as shown in Figure 1. In this position, the respective shielding portions 121 , 131 of the first and second patterns 120, 130 combine to cover substantially the entire surface of the viewing panel unit 100, which therefore prevents hazardous ionising and/or non - ionising radiation emitted adjacent the first or second panel from passing through the viewing panel unit.

[0046] An alternative embodiment of a viewing panel unit 200 according to the invention is shown in Figure 2. This embodiment is particularly suited for retro-fitting shielding means to viewing panel units of the prior art.

[0047] Many known viewing panel units have first, second and intermediary panels 101 , 102, 103, wherein at least the first panel 101 is configured with a first pattern 220 of substantially opaque portions 221 and substantially see-through portions 222, and the intermediary panel 103 is configured with a second pattern 230 of substantially opaque portions 231 and substantially see-through portions 232. [0048] The substantially opaque portions 221 , 231 are portions of each respective panel, which are obscured, masked or covered for achieving the conventional purpose of privacy. Such substantially opaque portions 221 , 231 of the prior art are often implemented by processing portions of the surface of the original panel 101 , 102, 103 to impede vision therethrough, for instance to impart swirls, dimples and other such surface artefacts apt to diffuse light passing therethrough. The substantially see-through portions 222, 232 are again portions of each respective panel, which are not obscured, masked or covered in any way- and, again, may consist simply of discrete portions of the original panel 101 , 103. [0049] In the embodiment of Figure 2, a third pattern 240 comprising substantially opaque portions 241 is cut from sheet material suitable for shielding hazardous ionising and/or non - ionising radiation, or cut into the sheet material forming a pattern support. The material is for instance mild steel, opaque vinyl or carbon fiber and the pattern has a depth of 1 millimeter or less. The third pattern 240 is configured so that its substantially opaque portions 241 correspond to and fully cover at least the substantially opaque portions 221 , 231 of each of the first and intermediary panels 101 , 103. [0050] For the purposes of not obscuring the description unnecessarily, the example assumes that the prior art first and second patterns 220, 230 are identical, however it will be readily understood by those skilled in the art that a respective third pattern 240 may need to be configured for each of the first and intermediary panels 101 , 103, if their respective first and second patterns 220, 230 vary in configuration relative to one another.

[0051] Accordingly, an iteration of the third pattern 240 is secured to each of the respective panel faces with suitable bonding means, in transverse alignment with one another as described hereinbefore. When the user actuates selective displacement means of the viewing panel unit, the intermediary panel 103 is displaced relative to the first and second panels 101 , 102, whereby the substantially opaque portions 241 of the third pattern of the intermediary panel 103 eventually occlude the substantially see-through portions 222 of the first pattern 220, as explained in relation to Figure 1. In this position, the respective shielding portions 241 of the third pattern 240 superimposed on each of the first and second patterns 220, 230 combine to cover substantially the entire surface of the viewing panel unit 200, which therefore prevents to prevent ionising and/or non - ionising radiation emitted adjacent the first or second panel from passing through the viewing panel unit.

[0052] An alternative embodiment of a viewing panel unit 300 according to the invention is shown in Figure 3. The viewing panel unit 300 is fitted to a door 301 and the intermediary panel 03 is in a first, open position, thus wherein vision through the unit is permitted, and hazardous ionising and/or non - ionising radiation are not emitted adjacent the first or second panel 101 , 102.

[0053] In this embodiment, the viewing panel unit 300 is referred to as a standard - fit unit and is a fully bonded, semi-hermetic unit not requiring any felt- covered metal housing. This is advantageous in medical environments, since such felt-covered metal housings can become unhygienic over time. The standard - fit unit 300 may be fitted in a position centred across the width 302 of the door 301 , and held in place with a bead 303 on either side, as shown in the Figure. Alternatively, The standard - fit unit 300 may be positioned so that the outer surface of either the first panel 101 or the second panel 102 is flush with one side 304, 305 of the door 301 , with a single bead 302 on the other (not shown). The beading may be made of timber or metal. The standard - fit unit 300 comprises first, second and third panels 101 , 102, 103 as described in relation to Figures 1 and 2. [0054] An alternative embodiment of a viewing panel unit 400 according to the invention is shown in Figure 4. The viewing panel unit 400 is fitted to the door 301 and the intermediary panel 103 is in a second, closed position, thus wherein ionising and/or non - ionising radiation emitted adjacent the first or second panel 101 , 102 are prevented from passing through the viewing panel unit 400.

[0055] In this embodiment, the viewing panel unit 400 is referred to as a flush - fit unit and is again a fully bonded, semi-hermetic unit. This viewing panel unit 400 is manufactured to suit the exact width 302 of the door 301 whereby, once fitted to the door, the respective outer surfaces 401 , 402 of the first and second panels 101 , 02 are flush with respective side 304, 305 of the door 301. The viewing panel unit 400 is sealed in position with silicone mastic, advantageously preventing the accumulation of dirt and/or bacteria in crevices or ledges. The flush - fit unit 400 comprises first, second and third panels 101 , 102, 103 as described in relation to Figures 1 and 2, and an additional panel 403 adjacent either the first or the second panel 101 , 102, parallel thereto and substantially transparent.

[0056] An alternative embodiment of a viewing panel unit 500 according to the invention is shown in Figure 5. The viewing panel unit 500 is fitted to the door 301 and the intermediary panel 103 is in the first, opened position as described in relation to Figure 3. [0057] In this embodiment, the viewing panel unit 500 is referred to as a retro - fit unit and is again a fully bonded, semi-hermetic unit. This viewing panel unit 500 is manufactured to allow a user to upgrade or alter the existing viewing panel of a door 301 with minimal disruption, whilst providing all the shielding benefits of the present invention. A stainless steel frame 501 apt to securely accommodate the viewing panel unit 500 is first secured to one side 305 of the door 301 , then the viewing panel unit 500 is mounted to the frame 501. This embodiment advantageously allows a fast and simple installation of a viewing panel unit according to the invention, leaving any existing window in-situ, with minimal disruption. The unit 500 may be fitted to either side of the door 30 . The frame 501 has bevelled sides with fully welded and polished corners, thus helping to reduce the build up of dust particles. The retro - fit unit 500 comprises first, second and third panels 101, 102, 103 as described in relation to Figures 1 and 2.

[0058] Figure 6 shows a detail of a viewing panel unit 600 according to a further embodiment of the invention, including circuit switching means 601 located within the under portion 12 of the interstitial volume 110. The circuit switching means 601 is connected to the power supply circuit 602 of one or more nearby appliances that are apt to emit ionising and/or non - ionising radiation and which the viewing panel unit 600 shields with comprising first, second and third panels 101 , 102, 103 as described in relation to Figures 1 and 2. The circuit switching means 601 is mounted adjacent the cam member 04 and disposed so as not to impede the travel of the cam member 104 in use.

[0059] In the embodiment shown, the circuit switching means comprises a spring - loaded switch 603. The switch 603 is biased into an opened position by a spring 604, whereby the circuit cannot provide supply to the nearby equipment 602, when the intermediary panel 103 is in the open position permitting viewing across the viewing panel unit 600. [0060] When the intermediary panel 103 is moved to the closed position for preventing ionising andfor non - ionising radiation from passing through the viewing panel unit 600, the bottom edge 105 of the intermediary panel 103 exerts a pressure upon the switch 603 against the spring bias. The intermediary panel 103 is mounted within the interstitial volume 110, and the shape of the cam member is so configured, that the bottom edge 105 exerts sufficient pressure to close the switch 603 when the intermediary panel 103 reaches the closed position, whereby the circuit can then supply power to the nearby equipment 602.