A protective case for an electronic mobile device
A transparent polymer case with a metallic tubular element and plug effectively guides flash light out and prevents stray light entry, addressing RF issues and size challenges, ensuring safe and functional electronic device use in hazardous areas.
Patent Information
- Application Number
- PCT/EP2025/062076
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-05-09
- Filing Date
- 2025-05-02
- Publication Date
- 2025-11-13
AI Technical Summary
Existing protective cases for electronic devices in hazardous environments face challenges with metal enclosures causing radio frequency issues, complex manufacturing, and impractical size due to stringent safety standards, while polymer cases reflect flash light back and allow stray light to affect camera performance.
A transparent polymer case with a metallic opaque tubular element and transparent plug to guide flash light efficiently out and prevent stray light entry, using a one-piece design with minimized joints and optimized for hazardous area compliance.
The solution ensures efficient light transmission without reflection or stray light interference, meeting hazardous area standards with a compact and lightweight design, reducing explosion risks and maintaining device functionality.
Smart Images

Figure EP2025062076_13112025_PF_FP_ABST
Abstract
Description
[0001] A PROTECTIVE CASE FOR AN ELECTRONIC MOBILE DEVICE
[0002] The present invention relates to a case for containing an electronic device and in particular, but not exclusively, to a case for protecting a mobile phone or tablet, including a camera module and flash, during use in hazardous areas.
[0003] It is generally known that the use of electronic devices in hazardous areas, such as within an environment containing the presence of flammable vapours, dust or fluids, can lead to an increased risk of fire and explosions. Electronic devices in such instances may act as an ignition source for flammable or otherwise ignitable material. Therefore, cases for electronic devices have been developed to prevent or at least reduce the risk of an ignition or explosion from igniting surrounding ignitable vapour or fluids. This is typically achieved by preventing ignitable substances from entering into the case and coming into contact with the electronic device, and by isolating an explosion or ignition within the case so as to prevent any contact with ignitable substances outside of the case.
[0004] Traditionally, enclosing an electronic device, such as a mobile phone or tablet, in a case to make them suitable for hazardous areas required the enclosure to be made from metal so that it can withstand the stringent testing requirements which are very difficult to satisfy using a polymer. In view of the advancements of mobile device technology, and more specifically the inclusion of touchscreens and camera modules, it is desirable for such cases to include transparent windows.
[0005] A case for an electronic device is described in GB2588858B which comprises a stainless steel front cover including a glass window to allow a user to view and interact with a touchscreen of the electronic device located in the case, and a stainless steel rear cover including a glass window to allow the electronic device to be wirelessly charged by induction and also to allow a camera module of the electronic device to ‘see’ through the rear cover. However, metal cases can cause radio frequency issues and the numerous joints between the various components add complexity and cost to the manufacturing process, require substantial sealing, and create a leak path if the seal fails. Furthermore, the case must be designed in accordance with hazardous standards, such as ATEX and lECEx, which require each joint to be a specific dimension (minimum distance across the joint) which is difficult to achieve, particularly when the camera module includes a closely arranged set of cameras, visual sensors, flashes, etc. all of which require visually transmissive material and minimum joint dimensions between the glass windows and metal cover / frame which in turn results in an impractically large case.
[0006] A solution may be to use a clear polymer case which has no effect on radio frequency functionality, allows for induction charging and eliminates the need for joints in the vicinity of the camera module. However, whilst some light passes through the clear polymer case when the flash of a camera module of the device located in the case is activated, some light from the flash is reflected back from the inner surface of the case and washes out the camera / s resulting in a poor or nonexistent image, whilst stray light from external sources can pass through the polymer case and illuminate the camera / s to also result in a poor or non-existent image.
[0007] It is an aim of certain embodiments of the present invention to provide a case for protecting an electronic device, including a camera and light, e.g. flash, module, and allowing light from the flash to efficiently exit the case and illuminate a subject without being reflected back towards the camera module by the case itself, and also preventing stray light from the flash or an external source passing through and into the case towards the camera module.
[0008] It is an aim of certain embodiments of the present invention to provide a cover for receiving a mobile device, wherein the cover is substantially transparent and includes a substantially opaque tubular element and a substantially transparent plug element located therein for efficiently guiding light from a light module of the mobile device out of the cover, whilst preventing stray light from the light module or an external source entering the cover and affecting a camera module of the mobile device.
[0009] According to a first aspect of the present invention there is provided a case for an electronic mobile device, comprising: a substantially transparent cover wall region including at least one port alignable with a light module of the mobile device when located in the case; a substantially opaque tubular element defining the port therethrough to guide light emitted from the light module through the cover wall region and out of the case and to prevent light entering the case towards a camera module of the mobile device located behind the transparent wall region; and a substantially transparent and elongate plug element located in the tubular element to seal the port whilst allowing the emitted light to pass therethrough.
[0010] Optionally, an inner surface of the tubular element defining the port is threaded and an outer surface of the plug element is correspondingly threaded to allow the plug element to be rotatably driven into the tubular element.
[0011] Optionally, the plug element comprises an elongate shank region extending from a flanged head region.
[0012] Optionally, the head region comprises diametrically opposed flat surfaces for engaging a tool to rotate the plug element with respect to the tubular element.
[0013] Optionally, the head region comprises a knurled finish.
[0014] Optionally, the case comprises an annular sealing element located between the tubular element and the head region of the plug element.
[0015] Optionally, the sealing element comprises an annular region located between the tubular element and the head region of the plug element, and a rim region extending from the annular region to surround the head region.
[0016] Optionally, the rim region comprises diametrically opposed flat surfaces corresponding to the opposed flat surfaces of the head region.
[0017] Optionally, the sealing element is substantially compressible and resilient.
[0018] Optionally, the sealing element is substantially opaque.
[0019] Optionally, the tubular element is metallic. Optionally, the transparent wall region comprises a plastics material and is overmoulded to the tubular element.
[0020] Optionally, the plug element comprises a polymer.
[0021] Optionally, the case comprises a sealing element disposed on an inner end of the tubular element for engagement with the light module of the mobile device and comprising an aperture axially aligned with the port of the tubular element.
[0022] Optionally, the cover wall region is configured to receive a rear side of the mobile device.
[0023] Optionally, the case comprises a peripheral wall region extending from the cover wall region, a frame attached to the peripheral wall region and defining a window aperture, and a transparent window element clamped between the frame and the peripheral wall region to close the window aperture.
[0024] Optionally, the case comprises at least one gasket disposed between the window element and the frame.
[0025] Optionally, the case comprises an outer cover to surround the case and defining an opening aligned with the window aperture of the frame.
[0026] Optionally, the outer cover is one-piece and comprises silicon rubber.
[0027] According to a second aspect of the present invention there is provided a method of manufacturing a case for an electronic mobile device, comprising: fixing a substantially opaque tubular element defining a port therethrough in a substantially transparent cover wall region of the case, wherein the port is alignable with a light module of the mobile device when located in the case; and locating a substantially transparent and elongate plug element in the tubular element to seal the port whilst allowing light emitted from the light module therethrough and out of the case.
[0028] Optionally, the method comprises over-moulding the cover wall region around the tubular element.
[0029] Optionally, the method comprises rotatably engaging a first thread of the plug element with a second thread of the tubular element to drive the plug element into the tubular element.
[0030] Optionally, the method comprises engaging a tool on a flanged head region of the plug element.
[0031] Optionally, the method comprises compressing a sealing element between the head region and the tubular element.
[0032] Optionally, the method comprises: attaching a frame defining a window aperture to a peripheral wall region extending from the cover wall region; and clamping a transparent window element between the frame and the peripheral wall region to close the window aperture.
[0033] Description of the Drawings
[0034] Certain embodiments of the present invention will now be described with reference to the accompanying drawings in which:
[0035] Figure 1 illustrates the exterior of a rear cover of a mobile phone case according to certain embodiments of the present invention;
[0036] Figure 2 illustrates the interior of the rear cover of Figure 1 ;
[0037] Figure 3 illustrates a sectional view through a camera region of the rear cover; Figure 4 illustrates a sectional view through a light port assembly of the camera region of the rear cover; and
[0038] Figure 5 illustrates an external rear view of the light port assembly.
[0039] Detailed Description
[0040] As illustrated in Figures 1 and 2, a rear cover 100 of a case assembly for containing and protecting a mobile device during use in hazardous areas includes a substantially planar rear cover wall region 102 and a side wall region 104 extending continuously around the periphery of the rear cover wall region and substantially perpendicularly therefrom. The rear cover 100 is a one-piece and substantially transparent polymer material formed by injection moulding, 3D printing, or the like. Providing a one-piece and transparent rear cover allows light into the cover and for camera modules of the mobile device to capture images of a subject located outside the rear cover. The one-piece construction also reduces the number of joints otherwise created between different components making up a case which could undesirably provide a leak path and in turn an explosion risk. Reducing the number of joints also minimises the size and weight of the rear cover and overall case assembly itself, and also manufacturing costs and material used.
[0041] The side wall region 104 of the rear cover includes a plurality of outwardly extending lugs 106 each including a threaded hole for receiving a screw 108 for attaching and sealing a front cover (not shown) to the rear cover 100 to form, inter alia, the case assembly. Aptly, the threaded hole in each lug 106 is provided by a metal insert, such as a brass insert, over which the polymer cover is moulded to anchor the inserts therein. Alternatively, the threaded inserts, such as stainless steel nuts, may be loosely located within the lugs to avoid any cracking or splitting of the plastic case caused by different thermal expansion rates between the metal inserts and the surrounding plastic of the case. The front cover is aptly in the form of a frame which clamps a glass window to a front surface 107 of the side wall region of the rear cover and on or above the front display of the mobile device. One or more gaskets may be located between the front and rear covers to seal, and optionally bond, the two components together and seal the joint therebetween. The gasket / s may extend over the joint between the window and the rear cover to also seal that interface. The case assembly is aptly located in a protective outer cover formed in silicone rubber or the like by for example compression moulding to thereby provide impact resistance to the case assembly located therein.
[0042] Alternatively, the rear cover may be used without a front cover / frame or window such that a display of the mobile device is directly accessible via the front opening of the rear cover defined by the side wall region. The side wall 104 may exclude the lugs and screws, particularly if the mobile device is not to be used in a hazardous environment and does not require sealed containment and full protection.
[0043] The rear cover 100 includes an annular recessed region 110 in the inner surface of the rear cover wall region 102 to reduce its thickness and to accommodate an induction charging ring for wireless induction charging of the mobile device when located in the rear cover. The rear cover also includes a plurality of sealed ports 112, 114, 116, 118 in the side wall region 104 each aligned with a speaker, microphone or button of the mobile device and configured to respectively allow sound waves into and out of the case from the speaker / s and to the microphone / s, and also to allow a user to operate various buttons or switches on the side of the mobile device via sealed pushrod assemblies (not shown), whilst ensuring the case meets the standards required if it is to be used in a hazardous or potentially explosive environment.
[0044] The rear cover wall region 102 includes a camera region 120 comprising a recessed inner surface 122 for accommodating a correspondingly sized and shaped raised portion of the mobile device, wherein the recessed inner surface 122 includes three camera recesses 124 to accommodate respective camera modules mounted in the raised portion, a sealed light port assembly 126 alignable with a light module, e.g. flash or strobe, of the mobile device, a scanner recess 128 to accommodate or alignable with a LiDAR scanner module of the mobile device, and a sealed microphone port 130 alignable with a microphone mounted in the raised portion of the mobile device. Providing a rear cover defining an interior space that closely, if not exactly, corresponds to the mobile device minimises, if not eliminates, the free internal volume between the mobile device and the rear cover which could undesirably be filled with a hazardous gas / dust or harbour oxygen which could encourage ignition and in turn an explosion. Minimising the free internal volume between the mobile device and the rear cover to less than 50cm3minimises the required length of any joints in the case as dictated by the ATEX and lECEx standards and thus ensures the overall case is as compact and lightweight as possible as opposed to conventional mobile device cases for use in hazardous areas which are notoriously bulky and heavy.
[0045] As illustrated in Figures 3 and 4, the sealed light port assembly 126 comprises a substantially opaque tubular element 132 defining a through port which is precisely aligned with the light module of the mobile device to efficiently guide the light emitted from the light module through the transparent rear cover wall region and out towards a subject to be illuminated, e.g. for photographing or videoing purposes. Desirably, the tubular element 132 also prevents stray light from the light module or an external source passing through the rear cover and affecting the camera modules. Aptly, the tubular element 132 is metallic, such as brass, and preferably substantially reflective to bounce the emitted light efficiently along the inside of the tubular element and out of the rear cover without any substantial losses. The tubular element 132 is aptly around 5-6mm long and aptly around 6-8mm in diameter. The tubular element may alternatively be longer than it is wide, such as to suit a thicker case wall than illustrated. The port through the tubular element is aptly around 5mm in diameter. Aptly, the inner surface of the port is threaded.
[0046] The correspondingly threaded elongate shank region 134 of a substantially transparent plug element 136 is screwed into the threaded port of the tubular element 132 by engaging a suitable tool, such as a spanner, on diametrically opposed flat surfaces 138 of a flanged head region 140 of the plug element and rotatably driving the plug element into the tubular element. The head region may also be used to remove the screw element 136 from the tubular element 132 if required, such as for cleaning or replacing. Alternatively, the port and the plug element may not be threaded and the plug element may slidably insert into the port by an interference fit and / or may be removably secured therein by mechanical means, such as a retaining bezel, a bayonet coupling, or the like, or may be fixed therein by adhesive or the like.
[0047] An inner end of the tubular element 132 may be configured to engage the mobile device and surround the light module to prevent any light emitted therefrom from straying outside the tubular element. Alternatively, a sealing element including an aperture corresponding in size and shape to the port may be provided on / around the inner end of the tubular element to continuously extend the port to the light module of the mobile device and prevent any light emitted from the light module not entering the port of the tubular element. Aptly, the sealing element is substantially resilient and compressible.
[0048] As illustrated in Figures 3 to 5, a rubber sealing element 1 2 is optionally provided between the head region 140 and the tubular element 132 to be compressed by the plug element 136 and seal the interface between the plug element and the tubular element. The sealing element 142 may solely comprise an annular region 144, akin to a washer, or as illustrated may also include a rim region 146 for containing the head region of the plug element. Aptly, the rim region 146 defines an interior corresponding to the outer surface of the head region and also includes diametrically opposed flat surfaces for the tool, such as a spanner, to engage such that the sealing element can remain in situ on the plug element during installation or removal into or from the tubular element 132. The sealing element also protects the head region of the plug element from the tool and during use. Aptly, the sealing element 142 is substantially opaque to prevent any light passing through and along the plug element from straying before exiting the head region thereof. Aptly, the outer surface of the head region may be substantially flat or may be substantially convex, e.g. domed, to encourage light exiting the surface to be dispersed outwardly by refraction at the surface.
[0049] Alternatively, the head region 140 of the plug element 136 may be continuously circular and not include the opposed flat surfaces but instead include knurling, such as parallel grooves and ridges extending around its outer surface, to allow a user or installer to grip the head region and manually rotate the plug element into or out of the tubular element. The rim region 146 of the sealing element is substantially resilient so could be urged away from the head region to allow the same to be gripped.
[0050] Further alternatively, the plug element 136 may not include the head region 140 or sealing element 142 and may simply be a threaded or non-threaded rod having means, such as a slot in its outer end surface or a knurled outer end region, for rotating or translating the same into or from the tubular element.
[0051] Desirably, the substantially transparent plug element 136 acts as a light pipe to tunnel light from the light module of the mobile device through the rear cover and out towards the subject to be illuminated without being reflected back of an inner surface of the rear cover and / or being lost / diluted within the cover material itself, whilst the substantially opaque tubular element 132 surrounding the plug element prevents stray light from the light module or elsewhere transferring into the rear cover and adversely affecting the camera modules and captured image / s.
[0052] Certain embodiments of the present invention therefore provide a case for containing and protecting an electronic mobile device including a camera and light, e.g. flash, module, and desirably allowing light from the flash to efficiently exit the case and illuminate a subject without being reflected back towards the camera module by the case itself, and also preventing stray light from the flash or an external source passing through and into the case towards the camera module. The case may comprise a front and / or rear cover for a mobile device wherein the camera and light modules are located on a front and / or rear side of the mobile device. The rear cover for example may be configured to be used alone or may form part of a case assembly to fully contain and protect the mobile device in a hazardous environment. Aptly, the electronic mobile device is a mobile phone or tablet. A method of manufacturing the case is also provided. The case according to certain embodiments of the present invention eliminates or at least reduces the risk of an explosion occurring in a hazardous environment, such as in the petrochemical, gas and natural gas, or biotech industries, when using a mobile device so in turn reduces the risk of environmentally harmful leaks and costly / energy inefficient downtime. The case according to certain embodiments of the present invention also allows a mobile device with a flash / strobe / light module to be used for communications, analysis or safety check purposes etc. within a hazardous environment which in turn allows the energy processing plant, for example, to continue being operational without costly and energy inefficient downtime.
Claims
Claims1 . A case for an electronic mobile device, comprising: a substantially transparent cover wall region including at least one port alignable with a light module of the mobile device when located in the case; a substantially opaque tubular element defining the port therethrough to guide light emitted from the light module through the cover wall region and out of the case and to prevent light entering the case towards a camera module of the mobile device located behind the transparent wall region; and a substantially transparent and elongate plug element located in the tubular element to seal the port whilst allowing the emitted light to pass therethrough.
2. The case according to claim 1 , wherein an inner surface of the tubular element defining the port is threaded and an outer surface of the plug element is correspondingly threaded to allow the plug element to be rotatably driven into the tubular element.
3. The case according to claim 1 or 2, wherein the plug element comprises an elongate shank region extending from a flanged head region.
4. The case according to claim 3, wherein the head region comprises diametrically opposed flat surfaces for engaging a tool to rotate the plug element with respect to the tubular element.
5. The case according to claim 3 or 4, wherein the head region comprises a knurled finish.
6. The case according to any of claims 3 to 5, comprising an annular sealing element located between the tubular element and the head region of the plug element.
7. The case according to claim 6, wherein the sealing element comprises an annular region located between the tubular element and the head region of theplug element, and a rim region extending from the annular region to surround the head region.
8. The case according to claim 7, wherein the rim region comprises diametrically opposed flat surfaces corresponding to the opposed flat surfaces of the head region.
9. The case according to any of claims 6 to 8, wherein the sealing element is substantially compressible and resilient.
10. The case according to any of claims 6 to 9, wherein the sealing element is substantially opaque.11 . The case according to any preceding claim, wherein the tubular element is metallic.
12. The case according to claim 11 , wherein the transparent wall region comprises a plastics material and is over-moulded to the tubular element.
13. The case according to any preceding claim, wherein the plug element comprises a polymer.
14. The case according to any preceding claim, comprising a sealing element disposed on an inner end of the tubular element for engagement with the light module of the mobile device and comprising an aperture axially aligned with the port of the tubular element.
15. The case according to any preceding claim, wherein the cover wall region is configured to receive a rear side of the mobile device.
16. The case according to any preceding claim, comprising a peripheral wall region extending from the cover wall region, a frame attached to the peripheral wall region and defining a window aperture, and a transparent window element clamped between the frame and the peripheral wall region to close the window aperture.
17. The case according to claim 16, comprising at least one gasket disposed between the window element and the frame.
18. The case according to claim 16 or 17, comprising an outer cover to surround the case and defining an opening aligned with the window aperture of the frame.
19. The case according to claim 18, wherein the outer cover is one-piece and comprises silicon rubber.
20. A method of manufacturing a case for an electronic mobile device, comprising: fixing a substantially opaque tubular element defining a port therethrough in a substantially transparent cover wall region of the case, wherein the port is alignable with a light module of the mobile device when located in the case; and locating a substantially transparent and elongate plug element in the tubular element to seal the port whilst allowing light emitted from the light module therethrough and out of the case.21 . The method according to claim 20, comprising over-moulding the cover wall region around the tubular element.
22. The method according to claim 21 , comprising rotatably engaging a first thread of the plug element with a second thread of the tubular element to drive the plug element into the tubular element.
23. The method according to claim 22, comprising engaging a tool on a flanged head region of the plug element.
24. The method according to claim 23, comprising compressing a sealing element between the head region and the tubular element.
25. The method according to any of claims 20 to 24, comprising: attaching a frame defining a window aperture to a peripheral wall region extending from the cover wall region; andclamping a transparent window element between the frame and the peripheral wall region to close the window aperture.
Citation Information
Patent Citations
An electronic device case
GB2588858B
Flash Lens for Mobile Phone Case
US20120018322A1
Optical attachment for a portable electronic device
WO2018010849A1