Protective goggles

Abstract

The invention provides protective goggles (100) comprising a frame (102); a sealing arrangement (106) configured to provide a seal between the frame and a face of a wearer; and a visor (104) connected to the frame. An air flow source is configured to generate an air flow into an ocular space (108) defined by the protective goggles. The protective goggles further comprise a feedback system comprising an output device, wherein the feedback system is configured to control the output device to notify the wearer of an operating condition of the protective goggles.

Description

[0001] PROTECTIVE GOGGLES

[0002] Field of the Invention

[0003] The present invention relates to protective goggles for protecting eyes of a wearer. The protective goggles include an air flow source for generating an air flow into an ocular space defined by the protective goggles. The present invention also relates to protective goggles and a mask for use in a modular respirator.

[0004] Background

[0005] A respirator mask is a device that is used to protect a wearer from dangerous materials or substances, for example chemical, biological, nuclear and radiological agents, and / or toxic industrial chemicals, and / or toxic industrial materials.

[0006] A respirator mask typically includes a nose cup that covers at least the nose and mouth of the user and provides a seal around the nose and mouth. The nose cup is provided either with a filter for filtering air inhaled into the nose cup by the user, or with a connector for connecting the nose cup to a supply of filtered air. The nose cup is also typically provided with an exhale valve through which exhaled air can be discharged from the nose cup. A respirator mask also typically includes a visor or goggles portion that covers the eyes of the user and protects the eyes of the user. The visor or goggles portion typically provides a seal around the eyes of the user.

[0007] The present invention has been devised in light of the above considerations.

[0008] Summary of the Invention

[0009] In general terms, the invention provides protective goggles for protecting a wearer’s eyes from dangerous materials or substances in the environment. For example, the protective goggles may be used as part of chemical, biological, radiological and nuclear (CBRN) protective equipment. The protective goggles can be combined with a mask, to provide a modular respirator. The protective goggles include a frame, a visor connected to the frame, and a sealing arrangement configured to form a seal between the frame and a face of the wearer. The protective goggles further include an air flow source which is configured to generate an air flow into an ocular spaced defined by the protective goggles. The air flow source can provide two functions. In particular, the air flow into the ocular space can cause a positive pressure (i.e. a pressure higher than atmospheric pressure) inside the ocular space, to assist in preventing contaminants from entering the ocular space. This can enhance a safety of the wearer, particularly in the context of CBRN defence. Additionally or alternatively, the generated air flow can serve to defog the visor, i.e. prevent or reduce condensation on the visor thereby improving visibility through the visor. This can facilitate wearing of the protective goggles for extended periods of time. The invention includes the various aspects of the protective goggles set out below.

[0010] In a first aspect of the invention, there is provided protective goggles comprising: a frame; a sealing arrangement configured to provide a seal between the frame and a face of a wearer; a visor connected to the frame; an air flow source configured to generate an air flow into an ocular space defined by the protective goggles; and a feedback system comprising an output device, wherein the feedback system is configured to control the output device to notify the wearer of an operating condition of the protective goggles.

[0011] In this manner, a wearer of the protective goggles can be notified in real-time by the feedback system of a current operating condition of the protective goggles. In this manner, the wearer can be rapidly alerted of any issues relating to operation of the protective goggles. This is particularly useful in the context of CBRN protection, where rapidly notifying the wearer of any issues with the protective goggles can help improve safety of the wearer. Various examples of output devices that can be used and operating conditions that can be notified to the wearer are provided below.

[0012] The feedback system may be configured to receive an output from a sensor which detects an operating condition of the protective goggles, and to control the output device based on (as a function of) the output from the sensor. For example, the feedback system may determine if the operating condition should be notified to the wearer, and if so, operate the output device to notify the wearer. In some examples, the feedback system may be configured to continuously notify the wearer of the operating condition of the protective goggles (e.g. so that the wearer is notified if the operating condition is normal or not). In other examples, the wearer may only be notified when the feedback system determines that the operating condition is not normal, e.g. if the output from the sensor falls outside a predetermined boundary.

[0013] The feedback system may comprise a controller which is configured to control the output device based on the output from the sensor. The controller can include any suitable electronic control device, such as a microcontroller or the like. Any control operations described in relation to the feedback system may be performed by the controller of the feedback system. The controller of the feedback system may correspond to the controller described below in relation to other aspects.

[0014] Herein, controlling the output device may comprise, for example, generating a notification or an alert with the output device. The type of notification or alert will depend on the type of output device used.

[0015] In some cases, the feedback system may be configured to receive an output from multiple sensors, each of which is configured to detect an operating condition of the protective goggles. The feedback system can then control the output device as a function of the outputs received from the multiple sensors. In some cases, there may be multiple output devices, so that the feedback system can notify the wearer of the operating condition associated with different parts of the protective goggles.

[0016] The feedback system may be configured to determine, based on an output from the sensor (or one or more sensors) if the detected operating condition is indicative of a problem with the protective goggles and, if there is determined to be a problem with the protective goggles, control the output device to notify the wearer of the problem. For example, the feedback system may be configured to compare the output from the sensor to a predetermined threshold, to determine if the detected operating condition is indicative of a problem with the protective goggles.

[0017] The frame may act as a support or holder for the visor. For example, the frame may be arranged to surround the visor. The visor may be mounted in the frame, e.g. the visor may be retained in the frame via a push-fit or interference connection between the frame and the visor. The frame may comprise a channel for receiving the visor.

[0018] The visor may be formed of a transparent or semi-transparent material, so that the wearer can see through the visor. The visor may also be referred to as an eyepiece. The frame is arranged to hold the visor in front of the wearer’s eyes, in use. The material of the visor can include, for example, polycarbonate, polyethylene terephthalate glycol (PETG), or acrylic.

[0019] The sealing arrangement is configured to provide a substantially airtight seal with the wearer’s face. The sealing arrangement may comprise a sealing surface which is configured to contact the wearer’s face (skin), to form a seal with the wearer’s face. The sealing arrangement may extend around an edge of the frame, so as to form a continuous seal around the wearer’s eyes. In other words, the sealing arrangement may extend around an edge (periphery) of the ocular space defined by the protective goggles. For example, the sealing arrangement may comprise a continuous sealing strip (which provides the sealing surface) which extends around an edge of the frame.

[0020] The sealing arrangement may be configured to conform to a shape of the wearer’s face, to allow effective sealing with the wearer’s face. Thus, the material of the frame and sealing arrangement may be a highly flexible material, such as an elastomeric material.

[0021] The air flow source may comprise any suitable device or apparatus suitable for generating an air flow into the ocular spaced of the protective goggles. For example, the air flow source may comprise a fan (such as a radial fan) or a pump configured to cause air to flow into the ocular space. The air flow source may be in fluid communication with the ocular space (e.g. via a passageway or channel in the frame), so that it can cause air to flow into the ocular space. As an example, the air flow source may be configured to generate an air flow rate of 0.5 litres per minute (Ipm) or more, e.g. around 1 Ipm. In some cases, the air flow rate into the ocular space may be between about 1 to 8 Ipm. This can facilitate maintaining a positive pressure inside the ocular space, as well as avoid build-up of moisture in the ocular space so as to prevent visor fogging.

[0022] An air flow path for the air flow generated by the air flow source may be defined in the protective goggles. In particular, the air flow path may pass through the ocular space, and extend between an air inlet (or air intake) and an air outlet of the protective goggles.

[0023] The air flow source may be integrated into the frame, as discussed in more detail below. Alternatively, the air flow source may be connected to the frame via an air flow passage, e.g. a tube or the like.

[0024] In line with the above, the air flow generated by the air flow source may generate a positive in the ocular space. This may serve to prevent contaminants from entering the ocular space, e.g. via any gap between the sealing arrangement and the wearer’s face. Additionally or alternatively, the air flow generated by the air flow source may serve to defog the visor. For example, the air flow can serve to remove condensation from an inner surface of the visor, and / or to remove moisture from the ocular space.

[0025] Here, the ocular space defined by the protective goggles corresponds to an inner spaced defined by inner surfaces of the visor, the frame, and the sealing arrangement. In use, the ocular space is located between the inner surface of the visor and the wearer’s eyes, and constitutes a volume which is enclosed by the protective goggles around the wearer’s eyes.

[0026] The feedback system may be configured to detect an operating condition of the air flow source and control the output device based on the operating condition of the air flow source. In this manner the wearer can be notified in real-time of the operating condition of the air flow source. Thus, the wearer can be alerted to a malfunction (problem) of the air flow source. The feedback system may comprise a sensor configured to detect the operating condition of the air flow source. The feedback system can then control the output device based an output signal from the sensor.

[0027] By way of example, the operating condition of the air flow source could include a speed (e.g. fan speed) of the air flow source, e.g. the sensor may include a sensor for detecting speed of the air flow source. In other words, the feedback system may comprise a speed sensor for detecting the speed (e.g. in revolutions per minute) of the air flow source. For instance, the speed sensor may comprise a tachometer configured to detect a speed of the air flow source (e.g. fan). The feedback system may then be configured to control the output device based on the speed of the air flow source. The feedback system may be configured to generate a notification (e.g. alert) with the output device if the speed of the air flow source (fan) is outside a predetermined range. Thus, when the air flow source speed is outside the predetermined range, the user is notified, making them aware of a potential issue with the air flow. The predetermined range may be set to correspond to a desired air flow rate through the protective goggles under regular operating conditions.

[0028] The speed of the air flow source may be indicative of an (amount of) air flow resistance along a path of the air flow. For instance, for a given level of power (or voltage) supplied to the air flow source, a high speed of the air flow source may be indicative of a high air flow resistance, and / or of a low air flow. On the other hand, a low speed of the air flow source may be indicative of a low air flow resistance, and / or of a high air flow. Accordingly, by detecting the speed of the air flow source, it is possible to monitor air flow resistance, e.g. so that sudden changes in air flow resistance can be detected. For example, this enables the system to detect an obstruction in the air flow path, and / or a leak in the protective goggles.

[0029] The feedback system may be configured to determine, based on (as a function of) the detected speed of the air flow source, an air flow resistance for the generated air flow. The feedback system may then be configured to generate a notification (or alert) with the output device, e.g. if the determined air flow resistance is outside a predetermined range. For instance, the feedback system may be configured to generate a notification if the determined air flow resistance is above a first predetermined threshold (e.g. as this may be indicative of an obstruction in the air flow path). Additionally or alternatively, the feedback system may be configured to generate a notification if the determined air flow resistance is below a second predetermined threshold (e.g. as this may be indicative of a leak in the protective goggles, or that the filter is not correctly connected).

[0030] The feedback system may store a predetermined relationship between the speed of the air flow source and the air flow resistance, e.g. in a memory of the controller. The feedback system may then be configured to determine the air flow resistance using the detected speed of the air flow source and the predetermined relationship. For instance, such a predetermined relationship may be in the form of a function or look-up table associating a speed of the air flow source with a corresponding air flow resistance. Such a predetermined relationship may be obtained experimentally, e.g. by performing calibration measurements to determine a speed of the air flow source with different levels of air flow resistance. For instance, the air flow source may be operated with a constant voltage level, and the speed of the air flow source may be measured for different levels of air flow resistance, e.g. by progressively obstructing the air flow. Additionally or alternatively, the predetermined relationship may be based on a theoretical model of air flow through the protective goggles.

[0031] In some cases, the operating (e.g. input) voltage of the air flow source may be adjustable (e.g. to control an air flow rate of the air flow source). In such a case, the feedback system may store multiple predetermined relationships between the speed of the air flow source and the air flow resistance, each predetermined relationship being associated with a respective operating voltage of the air flow source. Each predetermined relationship may be obtained as described above, e.g. by performing a calibration measurement where the air flow source is operated with the corresponding input voltage, and / or using a theoretical model of the air flow.

[0032] As another example, the operating condition of the air flow source could include a current drawn by the air flow source, e.g. the sensor may include a sensor for detecting the current drawn by the air flow source. As a further example, the operating condition of the air flow source could include an air flow rate provided by the air flow source, e.g. the sensor may include an air flow sensor for detecting an air flow rate of the air flow generated by the air flow source.

[0033] The protective goggles may further comprise a filter arranged to filter air in the air flow generated by the air flow source. Thus, air entering the ocular space is filtered, such that it may be substantially free of contaminants. The filter may comprise a filter medium which is configured to remove contaminants from the air flow.

[0034] The filter may arranged be upstream of the air flow source. Thus, the air flow source may be configured to draw air via the filter to generate the air flow into the ocular space. The filter may thus act as an air intake for the air flow source. In this manner, the air flow into the ocular space is filtered.

[0035] The filter may be disposed in a brow portion of the frame.

[0036] In some embodiments, the filter may be removably mounted (or mountable) in the frame; and the feedback system may be configured to determine, based on the detected operating condition of the air flow source, whether the filter is correctly mounted in the frame, and to generate a notification (e.g. alert) with the output device if it is determined that the filter is not correctly mounted in the frame. In this manner, the wearer can be automatically notified if the filter is not correctly mounted in the frame, so that they can quickly remedy the situation.

[0037] When the filter is correctly mounted in the frame, all of the air flow may pass through the filter before entering the ocular space. In contrast, when the air filter is not correctly mounted in the frame, at least a portion of the air flow into the ocular space may not pass through the filter. Here, the filter may be said to be not correctly mounted in the frame if the filter is not mounted in the frame (e.g. it is separate from the frame), and / or if it is only partly mounted in the frame. Thus, if the filter is not correctly mounted in the frame, then air may be able to flow around the filter, such that air may enter the ocular space without passing through the filter. In this manner, air flow resistance for the air flow generated by the air flow source will depend on whether the filter is correctly mounted in the frame or not. As a result, operating conditions of the air flow source, such as its speed and / or air flow rate will depend on whether the filter is correctly mounted in the frame. Therefore, the operating condition of the air flow source is indicative of whether the filter is correctly mounted in the frame.

[0038] As an example, the feedback system may comprise a speed sensor (e.g. tachometer) for detecting a speed of the air flow source (e.g. fan). The feedback system may then be configured to determine whether the filter is correctly mounted based on an output from the speed sensor. For instance, the feedback system may be configured to determine that the filter is not correctly mounted in the frame if the speed of the air flow source is outside of a predetermined range. In particular, the feedback system may determine that the filter is not correctly mounted in the frame if the speed of the air flow source is below a predetermined threshold. Indeed, a lower speed of the air flow source (e.g. fan) speed may be indicative of a lower air flow resistance (i.e. higher air flow) and hence that the filter is not correctly mounted.

[0039] The predetermined range and / or predetermined threshold may be associated with a corresponding operating (e.g. input) voltage for the air flow source. As mentioned above, in some cases, the operating voltage of the air flow source may be adjustable (e.g. to control an air flow rate of the air flow source). In such a case, predetermined range and / or predetermined threshold may be selected based on the operating voltage of the air flow source.

[0040] As another example, the feedback system may comprise an air flow sensor for detecting an air flow rate of the air flow generated by the air flow source. The feedback system may then be configured to determine whether the filter is correctly mounted based on an output from the air flow sensor. For instance, the feedback system may be configured to determine that the filter is not correctly mounted in the frame if the air flow rate exceeds a predetermined threshold. Indeed, a higher air flow rate may be indicative of a lower air flow resistance and hence that the filter is not correctly mounted.

[0041] As a further example, the feedback system may be configured to determine, based on (as a function of) the detected operating condition (e.g. speed and / or air flow rate) of the air flow source, an air flow resistance for the generated air flow. The feedback system may determine that the filter is not correctly mounted if the air flow resistance is below a predetermined threshold. The air flow resistance may be determined as described above. As described further herein, the filter may be removably mounted in a cavity in the frame of the protective goggles. The cavity may define an air intake for the air flow source, e.g. the air flow source may be configured to draw air through the air intake. The filter may be arranged (e.g. shaped) to form a seal (i.e. an airtight seal) with the frame when the filter is mounted in the cavity. This may ensure that air drawn via the intake passes through the filter. In other words, the filter may (completely) cover the air intake defined in the frame, and form a seal with the frame. If the seal between the filter and the frame is not be properly formed (e.g. because the filter is not correctly mounted in the cavity), air may leak into the air inlet without passing through the filter. In line with the discussion above, such an improper seal with the filter may be detected with the speed sensor, e.g. if the speed of the air flow source is below a predetermined threshold, and / or if the determined air flow resistance is below a predetermined threshold.

[0042] In some embodiments, the filter may be removably mounted in a cavity defined in the frame; the filter may comprise a tag, and the feedback system may comprise a tag reader configured to obtain information from the tag when the filter is mounted in the cavity; the feedback system may be configured to determine a filter lifetime based on the information obtained from the tag; the feedback system may be configured to control the output device to notify the wearer when a usage time of the filter exceeds the determined filter lifetime. In this manner, the user may automatically be alerted when the filter needs to be changed.

[0043] The filter being removably mounted in the frame enables the filter to be easily removed and replaced as needed. The cavity for receiving the filter may, for example, be defined in the brow portion of the frame. The cavity may have a shape that is complementary to the filter. For example, the cavity may be in the form of a groove or a channel that extends along the brow portion of the frame, e.g. between the first side wing portion and the second side wing portion of the frame. The cavity may be formed as part of a moulding process for making the frame. The filter may be retained in the cavity by friction with the frame. In this manner, no further fasteners may be needed for securing the filter in the frame, thus simplifying an assembly of the protective goggles. The filter may be curved, to match a curvature of the brow portion of the frame. This may facilitate integrating the filter into the frame.

[0044] The filter may comprise a filter holder that contains a filter medium, the filter holder being mountable in the cavity. This may facilitate mounting the filter in the frame, as it avoids having to mount the filter medium directly in the cavity. Thus, the filter (including the filter holder and filter medium) and can be assembled separately from the rest of the protective goggles, and then inserted into the cavity in the frame to complete the protective goggles. The filter holder may correspond to a housing of the filter. The filter holder may be arranged to enclose the filter medium.

[0045] The filter medium may comprise any medium suitable for filtering an air flow. For example, the filter medium may comprise an activated carbon material. The activated carbon material may comprise an activated carbon cloth, fabric and / or foam. The filter medium may additionally or alternatively comprise a particulate filter material. For example, a high efficiency particular air (HEPA) filter or high efficiency synthetic particulate air filter can be used. Particulate filter materials can include, for example, non-woven glass fibre filter, PTFE, electrostatic melt blown material. The tag may comprise any suitable type of tag. In some cases, the tag may be an electronic tag, such as a radio-frequency identification (RFID) tag. In such a case, the tag reader may comprise a first antenna for communicating with the electronic tag, the electronic tag comprising a memory which stores information, and a second antenna for communicating with the tag reader. Communication between the tag reader and the electronic tag may be one-way or two-way. For example, the tag reader may be configured to read information stored in the memory of the electronic tag.

[0046] In other cases, the tag may be a visible tag, on which information is displayed. The tag reader could then include an optical tag reader, configured to read the information displayed on the tag. Other types of tag could also be used, such as a magnetic tag, with a magnetic tag reader (e.g. magnetic sensor) in the frame.

[0047] The information obtained from the tag on the filter may be indicative of one or more of: authentication information, filter identification, filter type, filter liftetime, date of manufacture, operating parameters to be used with the filter, or similar. Using the obtained information from the tag, the feedback system can determine the lifetime of the filter (i.e. its maximum recommended usage time). For instance, different filter types, or filter identifiers may be associated with different lifetimes in a memory of the feedback system. Alternatively, the information obtained from the tag may directly indicate the filter lifetime.

[0048] When the feedback system determines that the usage time of the filter exceeds the determined filter lifetime, the feedback system may further be configured to, update information stored in the tag (where the tag is an electronic tag). In this manner, the tag may store an indication that its usage time exceeds the predetermined threshold. This may avoid the filter from being used again once its usage time has already exceeded the predetermined threshold. For example, if the same filter is installed again in the protective goggles, the feedback system may determine based on the information stored in the tag that the predetermined threshold of usage time has already been exceeded for the filter. The feedback system may then, for example, generate an alert to notify the user that the filter should be changed.

[0049] The feedback system may be configured to detect an operating condition of the filter and to control the output device based on the operating condition of the filter. In this manner, the wearer can be notified of the operating condition of the filter, to ensure that the air flowing into the ocular space is being properly filtered.

[0050] As an example, the operating condition of the filter could include a usage time of the filter. Thus, the feedback system could monitor a usage time of the filter (e.g. based on an amount of time the air flow source is activated) and, when the usage time of the filter exceeds a predetermined lifetime of the filter, the feedback system can control the output device to notify the wearer that the filter should be changed.

[0051] As another example, the operating condition of the filter could include an amount (e.g. volume) of air that has passed through the filter. The amount of air passing through the filter could be monitored, for example, based on a usage time and flow rate of the air flow source. Then, when the amount of air that has passed through the filter exceeds a predetermined threshold, the feedback system can control the output device to notify the wearer that the filter should be changed. The protective goggles may further comprise a battery, and the feedback system may be configured to detect an operating condition of the battery and control the output device based on the operating condition of the battery. In this manner, the wearer can be notified of the operating condition of the battery. For example, the feedback system may be configured to detect a remaining power level of the battery, and to control the output device to provide an indication of the remaining battery level. As another example, the feedback system may be configured to detect a fault with the battery.

[0052] The feedback system may be configured to detect a remaining power level of the battery, and when the remaining power level falls below a predetermined threshold, control the output device to notify the wearer, e.g. that the remaining power level of the battery is low.

[0053] The battery may be configured to power the air flow source, and / or any other electronic components in the protective goggles.

[0054] The frame may be formed of an elastomeric material. In this manner the frame may be formed of a flexible material, which facilitates conforming the frame and sealing arrangement to a shape of the wearer’s face to form an effective seal against the wearer’s face. For example, the frame can be formed as a single piece of elastomeric material via a moulding process. In this manner, all features of the frame can be formed as part of the moulding process, which can reduce a number of process steps for producing the protective goggles. The elastomeric material could, for example, include silicone, butyl rubber, a thermoplastic polyurethane (TPU), or a thermoplastic elastomer (TPE).

[0055] The elastomeric material may have a Shore A hardness of 70 or less. This results in a high level of flexibility of the, enhancing its ability to conform to the wearer’s face and to form a tight seal with the wearer’s face. In some cases, the elastomeric material may have a Shore A hardness of 60 or less, and in some cases of 50 or less. The elastomeric material may have a Shore A hardness between 30 and 70.

[0056] The sealing arrangement and the frame are integrally formed as a single piece of material. In this manner, the frame and the sealing arrangement are integrally formed as a single piece of material, i.e. as a single part. This may simplify a manufacturing process for the protective goggles. For example, the frame and sealing arrangement can be moulded as a single part, e.g. via a one-shot moulding process. Additionally, this arrangement can improve an integrity and performance of the protective goggles. In particular, forming the frame and the sealing arrangement as a single piece of material may avoid leaks arising between the sealing arrangement and the frame, thus allowing a high sealing efficiency of the protective goggles around the wearer’s eyes. This may be particularly beneficial in the context of CBRN protection, where any leak between the frame and the sealing arrangement could be highly dangerous for the wearer. Such a reduced leakage risk can also facilitate maintaining a positive pressure inside the ocular space. Further, a risk of the sealing arrangement becoming detached from the frame is reduced, thus improving a reliability and lifetime of the protective goggles. Forming the sealing arrangement and the frame as a single piece of material can also enhance flexibility of the frame and sealing arrangement. The material of the frame and sealing arrangement may be an elastomeric material, as discussed above.

[0057] The protective goggles may further comprise a sensor configured to detect a condition of the ocular space, wherein the feedback system is configured to provide feedback to a wearer based on the detected condition of the ocular space. Thus, the feedback system can include any of the sensors described below in relation to the second aspect of the invention. In this manner, the feedback system can notify the wearer of the detected condition of the ocular space. This may enable the wearer to ensure that the protective goggles are operating properly, and that the air in the ocular space is safe. For example, in line with the discussion below regarding the second aspect of the invention, the detected condition of the ocular space could include one or more of: pressure, temperature, humidity, air flow. In some cases, similarly to the discussion in relation to the second aspect of the invention, the feedback system may be configured to determine a risk of condensation on the inner surface of the visor (e.g. based on one or more of a detected pressure, temperature, and humidity in the ocular space), and to control the output device to provide an indication of risk of condensation on the inner surface of the visor. This may enable the wearer to take appropriate action to avoid condensation on the visor.

[0058] The output device may comprise one or more output devices, e.g. for generating different types of notifications and alerts for the wearer. The one or more output devices may be mounted in the frame of the protective goggles. In some cases, the one or more output devices may be connected to the flexible PCB described below. For example, the one or more output devices may be connected to the controller of the feedback system via the flexible PCB. The one or more output devices may be mounted on the support board described further below.

[0059] The output device may comprise an optical output device. In this manner, the output device can provide a visual indication of the detected operating condition to the wearer. For example, the output device can provide a visible notification or alert to the wearer.

[0060] The optical output device may include any type of output device suitable for generating a visible (visual) notification or alert to the wearer. For example, the optical output device one or more light sources. For example, the optical output device could include one or more light-emitting diodes (LEDs), e.g. three LEDs. As another example, the optical output device could include a display, such as a liquid crystal display (LCD) or the like. Providing multiple light sources and / or a display may enable specific information to be communicated to the wearer, e.g. relating to different aspects (e.g. operating conditions) of the protective goggles.

[0061] The optical output device may be mounted in the frame such that it is visible by the wearer in use. Mounting the optical output device in the frame enables the optical output device to be arranged near the wearer’s eyes, so that it may easily be visible. For example, the optical output device may be mounted in the brow portion of the frame, such that it is located over one or both of the wearer’s eyes in use. Additionally, providing the optical output device in the frame may avoid obscuring visibility through the visor, and the output device may remain in their field of view regardless of where they are looking.

[0062] The output device may comprise a haptic output device. For example, the haptic output device may comprise a vibration motor. In this manner, a haptic notification may be provided to the wearer via the haptic output device. This may enable more discreet notification, e.g. compared to a visual or audible notification, which may be advantageous in some contexts. The haptic output device may be mounted in the frame, so that when the haptic output device generates an alert (e.g. when it vibrates), this may be felt by the wearer.

[0063] The output device may be configured to output an audible notification. For example, the output device may comprise a speaker or other device capable of generating a sound for alerting or notifying the wearer.

[0064] Where the feedback system comprises multiple (e.g. two or more) output devices, the feedback system may be configured to select one of the output devices, and to control the selected output device to notify the wearer of the operating condition of the protective goggles. The output device may be manually selectable by the wearer, and / or automatically selected by the feedback system. In this manner, different output devices can be selected, e.g. depending on usage conditions of the protective goggles. For example, in some cases such as in low light conditions, it may be advantageous to use the haptic output device instead of a light source, e.g. to avoid giving away the wearer’s position. In other cases, such as an environment where there are many loud noises, it may be advantageous to use a light source to notify the user, as they may be less likely to feel vibrations from the haptic device over the noisy environment.

[0065] The protective goggles may comprise a user interface for selecting one of the output devices. For example, the interface could include a button, toggle, switch or any other suitable interface enabling the user to select one of the output devices. The feedback system may be configured to receive a user selection of one of the output devices from the user interface, and to control the selected output device to notify the wearer of an operating condition of the protective goggles.

[0066] Additionally or alternatively, the feedback system may be configured to automatically select one output devices. For example, the feedback system may be configured to select one of the output devices based on an environmental condition (parameter). Thus, the feedback system may comprise an environmental sensor for detecting an environmental condition, such as ambient light level or ambient sound level. The feedback system can then select one of the output devices based on (as a function of) an output from the environmental sensor, e.g. using a pre-programmed selection algorithm or set of selection rules.

[0067] According to a second aspect of the invention, there is provided protective goggles comprising: a frame; a sealing arrangement configured to provide a seal between the frame and a face of a wearer; a visor connected to the frame; an air flow source configured to generate an air flow into an ocular space defined by the protective goggles; a sensor configured to detect a condition in the ocular space; and a controller configured to control an air flow rate of the air flow source based on an output from the sensor.

[0068] In this manner, the air flow rate of the protective goggles can automatically be controlled based on (i.e. as a function of) a detected atmospheric condition in the ocular space. Thus, the air flow rate can be updated substantially in real-time, taking into account the detected condition in the ocular space. This can improve an ability of the protective goggles to maintain a desired positive pressure in the ocular space, and / or enhance a defogging performance of the protective goggles. For example, if the output of the sensor indicates that fogging is likely to occur, the air flow rate provided by the air flow source may be increased in order to prevent, reduce or mitigate fogging. As another example, if the output of the sensor indicates that pressure in the ocular space is dropping, the air flow rate can be increased to increase the pressure inside the ocular space.

[0069] Accordingly, the combination of the air flow source with a sensor for detecting a condition in the ocular space can reduce a risk of leakage of contaminants into the ocular space and / or improve a wearability of the protective goggles, such that the protective goggles provide effective protection in CBRN conditions.

[0070] Any features described in relation to the first aspect of the invention are equally applicable to the protective goggles of the second aspect (and vice versa).

[0071] The frame, sealing arrangement and visor may be as described above in relation to the first aspect of the invention. Likewise, features of the frame, sealing arrangement and visor described in the second aspect are applicable to the first aspect.

[0072] The air flow source may be as described above in relation to the first aspect of the invention. For example, the air flow source may comprise a fan (e.g. radial fan) or a pump configured to generate the air flow into the ocular space.

[0073] The condition in the ocular space detected by the sensor can include any property of the ocular space which can be used for controlling the positive pressure and / or defogging in the ocular space. For example, the detected condition may be indicative of a risk of condensation on an inner surface of the visor. In this manner, the output from the sensor can be used to control the air flow source to reduce a risk of fogging of the visor. As another example, the detected condition may be indicative of a pressure in the ocular space, such that the output from the sensor can be used to control the air flow source to provide a desired pressure in the ocular space.

[0074] The protective goggles can include one or more sensors, each sensor being configured to detect a respective condition of the ocular space. The controller can then control the air flow rate of the air flow source based on output signals received from each of the one or more sensors. Examples of different types of sensors and control operations are provided below.

[0075] The controller may be implemented via any suitable computing (or processing) device, such as a microcontroller. The controller may be configured with a predetermined set of instructions for controlling operation of the air flow source as a function of the output received from the sensor. The set of instructions may be in the form of an algorithm arranged to take the output from the sensor (or the one or more sensors) as an input, and to provide control instructions for the air flow source as an output. The controller can then control the air flow source in accordance with the output control instructions, e.g. to adjust an air flow rate of the air flow source. As an example, the controller may be configured to control the air flow rate by comparing the output of the sensor to a setpoint (target value) or to a predetermined threshold.

[0076] Here, control of the air flow rate of the air flow source can include increasing, decreasing, and / or maintaining the air flow rate. This can be achieved, for example, by controlling power supplied to the air flow source and / or by controlling a speed of the air flow source. The sensor may be configured to detect a condition of air in the ocular space. Thus, the detected condition can correspond to a property of the air (atmosphere, gas) and / or air flow in the ocular space. In this manner, the air flow rate can be automatically controlled based on a property of the atmosphere in the ocular space. The detected condition could, for example, include one or more of pressure inside the ocular space, temperature in the ocular space, air humidity in the ocular space.

[0077] The sensor may be configured to detect a condition (property) of the visor, which defines a boundary of the ocular space. For example, the sensor may be configured to detect a temperature of the visor, which may be indicative of a risk of condensation on the visor. As another example, the sensor may be configured to detect condensation on the visor.

[0078] The output of the sensor may be indicative of a risk of condensation on an inner surface of the visor. In this manner, the controller can control the air flow rate to reduce a risk of condensation on the inner surface of the visor. For example, if the output of the sensor indicates that there is a high risk of condensation on the inner surface of the visor, the controller can increase the air flow rate, which may contribute to removing moisture from the ocular space and / or inhibit condensation on the inner surface of the visor. On the other hand, if the output of the sensor indicates that there is a low risk of condensation on the inner surface of the visor, the controller can reduce the air flow rate, e.g. to conserve battery power. Various types of sensor can be used to provide an indication of condensation risk, several examples of which are provided below. In general, a risk of condensation on the visor can depend on a variety of factors, including temperature in the ocular space, humidity level in the ocular space, pressure in the ocular space, temperature of the visor, and / or air flow rate through the ocular space. Accordingly, detection of any of these properties can serve to give an indication of risk of condensation on the inner surface of the visor.

[0079] The controller may be configured to adjust the air flow rate to prevent, or reduce a risk of, fogging of the visor, i.e. formation of condensation on the inner surface of the visor.

[0080] The controller may be configured to determine a risk of condensation on the inner surface of the visor based on the output from the sensor, the controller being configured to control the air flow rate of the air flow source as a function of the determined risk of condensation. In this manner, the controller can control the air flow rate to reduce the risk of condensation on the visor. In line with the above, outputs from various types of sensor can be used to determine a risk of condensation. The controller may use a predetermined relationship between the output of the sensor and risk of condensation to determine the risk of condensation on the visor.

[0081] The sensor may comprise a temperature sensor for detecting a temperature in the ocular space. Condensation on the inner surface of the visor depends on the temperature in the ocular space, such that the detected temperature can be used as an indicator of condensation risk. In general terms, a lower temperature may be indicative of a higher risk of condensation. In some cases, the detected temperature can be compared to a predetermined threshold to determine a risk of condensation on the visor. For example, the detected temperature can be compared to a dew point in order to determine a risk of condensation on the visor. The dew point is the temperature at which moisture condenses out of air. For instance, if the temperature is within a predetermined threshold of the dew point, or if the temperature is below the dew point, the controller can determine that there is a high risk of condensation forming on the inner surface of the visor, in which case the controller can increase the air flow rate. The dew point can be a predetermined value (threshold), or it can be determined taking into account atmospheric conditions such as air pressure and humidity level.

[0082] The temperature sensor can be configured to detect a temperature of air in the ocular space. Additionally or alternatively, the temperature sensor can be configured to detect a temperature of the visor. In some cases, two temperature sensors may be provided: one for detecting the air temperature in the ocular space and one for detecting the visor temperature.

[0083] In some cases, an external temperature sensor may be provided for detecting an ambient temperature (i.e. outside the ocular space). The external temperature sensor can be provided in addition to any of the other sensors mentioned herein. For example, the protective goggles can include an internal sensor (e.g. for detecting temperature in the ocular space) and an external temperature sensor for detecting ambient temperature. This enables the temperature inside and outside the ocular space to be compared, which may facilitate determining a risk of condensation forming on the inner surface of the visor. Indeed, the risk of condensation is related to a difference between the temperature inside the ocular space and the temperature outside the ocular space. For example, the controller may be configured to determine that there is a risk of condensation forming on the inner surface of the visor if the temperature in the ocular space (obtained from the internal temperature sensor) is below the ambient temperature (obtained from the external temperature sensor). The controller can then control the air flow source to increase the air flow rate, e.g. to reduce the risk of condensation forming on the visor.

[0084] The external temperature sensor may be mounted in the frame such that it is exposed to an outside of the frame, i.e. to an ambient atmosphere surrounding the protective goggles.

[0085] The sensor may comprise a humidity sensor for detecting a humidity level in the ocular space. Condensation on the inner surface of the visor depends on the humidity level of air in the ocular space, such that the detected humidity level can be used as an indicator of condensation risk. In general terms, a higher humidity level may be indicative of a higher risk of condensation. In some cases, the detected humidity level can be compared to a predetermined threshold to determine a risk of condensation on the visor. For example, if the detected humidity level exceeds a predetermined threshold, the controller may be configured to increase the air flow rate, to reduce a risk of condensation on the inner surface of the visor. Additionally or alternatively, the detected humidity level may be used by the controller for estimating a current dew point, which can then be used to estimate a risk of condensation as mentioned above. The humidity sensor could be a resistive or capacitive type sensor (e.g. where a resistance or capacitance of the sensor varies as a function of humidity level).

[0086] The sensor may comprise a condensation sensor, for detecting condensation in the ocular space. In this manner, the output from the condensation sensor can be used as an indication of the risk of formation of condensation on the inner surface of the visor. Thus, the controller can rapidly react to the formation of condensation in the ocular space, to remove the condensation and / or avoid further condensation. Thus, when the output of the condensation sensor indicates that there is condensation in the ocular space, the controller can increase the air flow rate, to reduce the risk of condensation on the visor and / or remove condensation from the visor. As an example, the condensation sensor may be a resistive sensor (e.g. where a resistance of the sensor varies as a function of condensation on a surface of the sensor).

[0087] The output of the sensor may be indicative of an air pressure in the ocular space. In this manner, the controller can use the output of the sensor for controlling the pressure in the ocular space. This may facilitate maintaining a desired (target) positive pressure in the ocular space. In this manner, the air pressure in the ocular space can be automatically controlled, using the output from the sensor as feedback. This may ensure that an adequate pressure is maintained in the ocular space to prevent contaminants in the environment from entering the ocular space, as well as maintain a comfortable pressure level for the user. The controller may be configured to use the output of the sensor in a control loop (feedback loop) for controlling the air flow rate of the air flow source, e.g. to achieve a target pressure in the ocular space. For example, the air flow rate can be increased to increase the pressure in the ocular space, and the air flow rate can be decreased to decrease the pressure in the ocular space. More generally, the controller may control the air flow rate to balance the air flow into the ocular space with an air flow (and / or air leakage) out of the ocular space to achieve a target pressure in the ocular space.

[0088] Additionally or alternatively to using the output of the sensor for maintaining a positive pressure in the ocular space, the output sensor (pressure sensor) can provide an indication of risk of condensation on the inner surface of the visor. Condensation on the inner surface of the visor depends on the air pressure in the ocular space, such that the output indicative of air pressure can be used as an indicator of condensation risk. In general terms, a higher pressure in the ocular space may be indicative of a higher risk of condensation. In some cases, the output indicative of air pressure can be compared to a predetermined threshold to determine a risk of condensation on the visor. For example, if the detected air pressure exceeds a predetermined threshold, the controller may be configured to increase the air flow rate, to reduce a risk of condensation on the inner surface of the visor. Additionally or alternatively, the output indicative of air pressure may be used by the controller for estimating a current dew point, which can then be used to estimate a risk of condensation as mentioned above.

[0089] Where the pressure sensor provides an output indicative of pressure in the ocular space, the sensor can comprise a pressure sensor configured to detect pressure in ocular space. The protective goggles may further comprise a second pressure sensor for sensing an ambient air pressure (e.g. outside the protective goggles), wherein the controller is configured to control the air flow source in response to a difference between the ocular space air pressure and the ambient air pressure. This may ensure that a suitable pressure differential between the ocular space and the ambient air is maintained. The first pressure sensor may be arranged (positioned) so that it is exposed to the ocular space in the protective goggles, whilst the second pressure sensor may be arranged (positioned) exposed so that it is exposed to ambient air outside the ocular space. In some cases, the pressure sensor may comprise a differential pressure sensor, the output of the differential pressure sensor being indicative of a pressure differential between the ocular space and ambient air. Alternatively to using a pressure sensor for detecting pressure in the ocular space, the sensor may be configured to detect the air flow rate and / or a current draw of the air flow source to provide the output indicative of pressure in the ocular space. For example, current draw may be higher if the pressure outside the ocular space is greater than pressure within the ocular space, and lower if the pressure outside the ocular space is less than pressure within the ocular space. A higher air flow rate may be indicative of a greater pressure differential where the pressure inside the ocular space is higher than outside the ocular space. A tachometer can be used for detecting a fan speed of the air flow source, to provide an indication of air flow rate and / or pressure in the ocular space.

[0090] Various sensor types are mentioned above. The protective goggles of the invention can include one or more of these sensor types. Combining multiple sensor types (e.g. temperature, humidity, and / or pressure) can enhance the controller’s ability to predict when condensation on the inner surface of the visor is likely to occur, improving the controller’s ability to reduce or avoid condensation on the inner surface of the visor.

[0091] The sensor (or sensors where multiple sensors are used) may be mounted in the frame, e.g. such that they are exposed to the ocular space inside the protective goggles. For example, the sensor(s) may be mounted in a brow portion of the frame.

[0092] The air flow source may comprise a radial fan. Thus, the air flow rate may be adjustable by adjusting a speed of the fan. A radial fan provides a compact and lightweight air flow source which is nevertheless able to provide suitable air flow rates for maintaining a positive pressure in the ocular space and / or defogging the visor.

[0093] In other embodiments, the air flow source may be a pump, such as a micropump or the like.

[0094] The air flow source may be configured such that the air flow rate is adjustable between 1 and 8 Ipm, for example. This can facilitate maintaining a positive pressure inside the ocular space, as well as avoid build-up of moisture in the ocular space so as to prevent visor fogging.

[0095] The air flow source may be configured to direct the air flow onto at least a portion of an inner surface of the visor. In this manner, the air flow source can act to defog the inner surface of visor, which may improve visibility through the visor. For example, the first air flow source may be configured to direct the air flow onto portion of the visor located in front of the wearer’s eyes in use.

[0096] The outlet of the air flow source may comprise a nozzle for directing the air flow onto a portion of the inner surface of the visor. In this manner, the air flow can be effectively directed onto the inner surface of the visor, which may improve a defogging performance. Moreover, use of a nozzle may serve to accelerate the air flow, which can enhance the air flow’s ability to remove moisture from the inner surface of the visor.

[0097] In some cases, the outlet of the air flow source can include a one-way valve, to prevent air from flowing out of the ocular space via the outlet of the air flow source.

[0098] The protective goggles may further comprise a power source, such as a battery (e.g. rechargeable battery), for powering the air flow source and controller. For example, the power source can comprise a battery (e.g. a rechargeable battery) mounted in the frame of the protective goggles. Other locations for the power source are also contemplated. For instance, the power source may be mounted on a head strap of the protective goggles, or may be provided as an external power source which is connectable to the protective goggles. Where an external power source is used, the protective goggles may comprise a power connector for receiving power from the external power source. As an example, a battery pack may be provided in a helmet. A connector may be then be provided for connecting the battery pack in the helmet to the protective goggles.

[0099] The frame may comprise one or more exhaust outlets to allow air to flow out of the ocular space. Thus, the air flow source can generate a continuous air flow which flows into the ocular space, and which exits the ocular space via the one or more exhaust outlets. Such a continuous air flow through the ocular space can serve to prevent contaminants from entering the ocular space, as well as help remove moisture from the ocular space to prevent or reducing fogging of the visor. So, for example, increasing the flow rate of the air flow source increases the flow of air through the ocular space, increasing a rate at which moisture can be removed from the ocular space.

[0100] The one or more exhaust outlets may comprise a first exhaust outlet arranged to be located under a left eye of the wearer, and a second exhaust outlet arranged to be located under a right eye of the wearer. Thus, in use an exhaust outlet may be located under each eye of the wearer. In this manner, the air flow may pass over (or adjacent) portions of the visor located in front of the wearer’s eyes, contributing to reducing of fogging in front of the wearer’s eyes. Additionally, positioning the exhaust outlets under the wearer’s eyes allows any fluids in the ocular space (e.g. condensation and / or sweat) to flow downwards towards the exhaust outlets, such that the exhaust outlets can also act as drainage channels for evacuating fluid from the ocular space.

[0101] Each of the one or more exhaust outlets may comprise a plurality of apertures, and a filter material covering the plurality of apertures. The plurality of apertures may allow air to flow out of the ocular space, whilst the filter material may serve to prevent contaminants from entering the ocular space via the apertures. The filter material could include, for example, a foam, felt or fabric material arranged to cover the plurality of apertures.

[0102] The air flow source may be a first air flow source arranged in a first side wing portion of the frame, the first air flow source being configured to generate a first air flow into the ocular space; and wherein the protective goggles may further comprise: a second air flow source arranged in a second side wing portion of the frame, the second air flow source being configured to generate a second air flow air flow into the ocular space; and wherein the controller is configured to control an air flow rate of the first air flow source and an air flow rate of the second air flow source based on an output from the sensor. In this manner, an air flow source can be arranged on either side of the protective goggles, such that in use the air flow sources are disposed on either side of the wearer’s face. This arrangement contributes to making air flow in the ocular space more symmetrical and evenly distributed. This may facilitate maintaining a positive pressure within the ocular space, as well as improve defogging of the visor. For example, the first air flow from the first air flow source can be directed towards a first portion of the visor located in front of the wearer’s left eye, and the second air flow from the second air flow source can be directed towards a second portion of the visor located in front of the wearer’s right eye. Additionally, providing air flow sources on either side of the protective goggles may improve a balance of the goggles, contributing to improved wearer comfort.

[0103] The first air flow source may be located in a first cavity defined in the first (e.g. left-hand side) side wing of the frame, and the second air flow source may be located in a second cavity defined in the second (e.g. right-hand side) side wing of the frame.

[0104] Herein, a side wing portion of the frame may correspond to a portion of the frame which projects laterally away from a side edge of the visor. For example, the first side wing portion may correspond to a portion of the frame arranged on a left-hand side of the visor, and the second side wing portion may correspond to a portion of the frame arranged on a right-hand side of the visor. The left-hand side and right-hand side can be defined with respect to a wearer of the protective goggles.

[0105] Any of the features described above in relation to the first air flow source are equally applicable to the second air flow source. For example, the outlet of the first air flow source can include a nozzle and / or one-way valve. The first and second air flow sources can be implemented using a same type of air flow source, e.g. second air flow source can be implemented using a radial fan as discussed above. The first air flow source and the second air flow source can be arranged substantially symmetrically about a middle plane of the protective goggles.

[0106] The controller may be configured to control the first and second air flow sources such that they have a same air flow rate, the air flow rate being determined based on the output of the sensor (or the one or more sensors). In this manner, the first air flow and the second air flow can be substantially symmetrical about the middle plane of the protective goggles. This also means that the controller may only need to use a single control loop for controlling both the first and second air flow sources. Using the same controller for both the first and second air flow sources further contributes to reducing a weight of the protective goggles, and can simplify a construction of the protective goggles.

[0107] Together, the first air flow and the second air flow may constitute (i.e. add up to) an air flow rate between about 1 Ipm and 8 Ipm. In other words, each air flow source may provide an air flow rate of between about 0.5 Ipm and 4 Ipm.

[0108] The controller can be connected to each of the first and second air flow sources, e.g. via suitable electrical connections extending within the frame.

[0109] The protective goggles may further comprise an air intake defined in a brow portion of the frame, wherein the first air flow source and the second air flow source are each configured to draw air from the air intake to generate the first air flow and the second air flow, respectively. In this manner, a common air intake in the brow portion of the frame is used for both air flow sources, thus contributing to making the protective goggles more compact and simplifies their construction. For example, one or more air inlets may be provided in the brow portion, through which air can be drawn by the first and second air flow sources. Respective air flow channels (passageways) may be defined in the frame to connect the air intake to the first air flow source and the second air flow source. The air intake may comprise a filter mounted in the brow portion of the frame, the filter being arranged to filter air drawn via the air intake. Accordingly, air drawn via the intake by the first air flow source and the second air flow source passes through the filter, such that air blown into the ocular space by the air flow sources is filtered. Thus, a single filter can be used at the air take for filtering air in both air flows.

[0110] Herein, the brow portion of the frame may correspond to a portion of the frame which is arranged to extend over (above) the wearer’s eyes, when in use. For example, the brow portion may be arranged against the wearer’s forehead in use. The brow portion may extend between a left-hand side wing of the frame and a right-hand side wing of the frame. The brow portion may be curved, e.g. to conform to a curvature of the wearer’s forehead.

[0111] The filter may comprise one or more air inlets, a first air outlet arranged towards a first end of the filter and in fluid communication with the first air flow source, and a second air outlet arranged towards a second end of the filter and in fluid communication with the second air flow source. Accordingly, air entering the filter via the one or more air inlets is split between the first and second air outlets to enter the first air flow and the second air flow, respectively. Thus, the one or more air inlets of the filter may act as the air intake of the protective goggles.

[0112] Placing the first air outlet and the second air outlet towards (e.g. at or near) respective ends of the filter may ensure that air must flow through a certain length of the filter before reaching the air outlets, to ensure effective filtering. The first end of the filter may be adjacent the first side wing portion of the frame, whilst the second end of the filter may be adjacent the second side wing portion of the frame.

[0113] The one or more air inlets may comprise an air inlet arranged in a central portion of the filter (e.g. centred between the first end and the second end of the filter). In this manner, air entering via the air inlet in the central portion must flow in the filter from the central portion to the first end to exit via the first air outlet, and from the central portion to the second end to exit via the second air outlet. This may ensure that good filtering efficiency of the air in the first and second air flows.

[0114] The one or more air inlets may be arranged substantially symmetrically about a middle of the filter. This may provide symmetrical filtering performance for the first and second air flows. Here, the middle of the filter may correspond to a mid-point of the filter between the first end and the second end of the filter.

[0115] The filter described in the second aspect of the invention may correspond to the filter described above in relation to the first aspect. Accordingly, features of the filter described in relation to the first aspect are applicable to the second aspect (and vice versa).

[0116] A first air flow channel defined in the frame may fluidly connect the air intake to the first air flow source, and a second air flow channel defined in the frame may fluidly connect the air intake to the second air flow source. Thus, air drawn in via the air intake is split between the two air flow channels to provide the first and second air flows, respectively. Defining the first and second air flow channels in the frame contributes to making the protective goggles more compact and of simpler construction. For example, the first air flow channel may connect the first air outlet of the filter and an inlet of the first air flow source, and the second air flow channel may connect the second air outlet of the filter and an inlet of the second air flow source. In other words, the first air flow channel may extend through a first portion of the frame between the air intake (e.g. first filter outlet) and the (inlet of) the first air flow source, and the second air flow channel may extend through a second portion of the frame between the air intake (e.g. second filter outlet) and the (inlet of) the second air flow source. Thus, the first air flow channel may be surrounded by material of first portion of the frame, e.g. to provide an airtight connection between the first outlet of the filter and the inlet of the air flow source. Likewise, the second air flow channel may be surrounded by material of the second portion of the frame, e.g. to provide an airtight connection between the second outlet of the filter and the inlet of the second air flow source.

[0117] Herein, two components being fluidly connected may mean that the two components are connected such that a fluid (e.g. air) can flow from one component to the other.

[0118] According to a third aspect of the invention, there is provided a method of operating protective goggles, the protective goggles comprising a frame, a sealing arrangement configured to provide a seal between the frame and a face of a wearer, a visor connected to the frame, and an air flow source configured to generate an air flow into an ocular space defined by the protective goggles, wherein the method comprises: detecting with a sensor of the protective goggles, a condition of the ocular space; and controlling an air flow rate of the air flow source based on an output from the sensor.

[0119] The method of the third aspect of the invention can be used for operating the protective goggles of the second aspect of the invention. Accordingly, any features described in relation to the second aspect of the invention are equally applicable to the third aspect of the invention (and vice versa).

[0120] The step of controlling the air flow rate may be performed by a controller of the protective goggles, e.g. the controller described in relation to the second aspect of the invention.

[0121] Any configuration features of the controller mentioned in relation to the second aspect of the invention can be included as steps of the method of the third aspect of the invention. In particular, any features described above relating to control of the air flow rate using outputs from one or more sensors can be included in the method.

[0122] The method may comprise monitoring an air pressure within the ocular space; and adjusting the air flow rate provided by the air flow source responsive to the atmospheric pressure.

[0123] In some cases, monitoring the atmospheric pressure may comprise monitoring an air flow rate or a current draw of the air flow source.

[0124] According to a fourth aspect, the invention provides protective goggles comprising: a frame; a sealing arrangement configured to provide a seal between the frame and a face of a wearer; a visor connected to the frame; an air flow source mounted in the frame and configured to generate an air flow into an ocular space defined by the protective goggles; and a flexible printed circuit board disposed in the frame, the flexible printed circuit board being connected to the air flow source.

[0125] Providing a flexible printed circuit board (PCB) in the frame can facilitate connecting control electronics and / or a power source (e.g. battery) to the air flow source, and contribute to making the protective goggles more compact and light weight. In particular, using a flexible PCB avoids having to provide individual wires between electrical components in the protective goggles, and provides a compact and lightweight solution for connecting the electrical components together. Furthermore, as the PCB is flexible, it does not hinder flexing or bending of the frame and the sealing arrangement. This allows the frame and sealing arrangement to flex and bend, so as to conform with a shape of the wearer’s face to form a substantially airtight seal with the wearer’s face. Moreover, as the flexible PCB can bend with the frame, it does not break when the frame is bent, thus improving a reliability and durability of the protective goggles.

[0126] Any features described in relation to the previous aspects of the invention are equally applicable to the protective goggles of the fourth aspect (and vice versa).

[0127] The frame, sealing arrangement and visor may be as described above in relation to preceding aspects of the invention.

[0128] The air flow source may be as described above in relation to the first aspect of the invention. For example, the air flow source may comprise a fan (e.g. radial fan) or a pump configured to generate the air flow into the ocular space.

[0129] Various electrical and / or electronic components of the protective goggles may be connected to the flexible PCB, to allow for powering and control of the air flow source.

[0130] The protective goggles may comprise a power source (e.g. a battery) connected to the flexible PCB. In this manner, for example, the air flow source can receive power from the power source via the flexible PCB.

[0131] The protective goggles may comprise a controller for controlling the air flow source, e.g. for controlling an air flow rate of the air flow source. The controller may be mounted on or connected to the flexible PCB. In this manner, the controller can control operation of the air flow source via the flexible PCB. For example, the controller may be configured to control an amount of power provided to the air flow source by the power source.

[0132] The protective goggles may comprise one or more sensors that are connected to the flexible PCB. For example, one or more of the sensors discussed above in relation to the first or second aspect of the invention may be connected to the flexible PCB. Thus, the controller may be connected to the one or more sensors via the flexible PCB, e.g. so that the controller can control the air flow source based on an output from the one or more sensors.

[0133] The flexible PCB may comprise a flexible substrate film made of a dielectric (electrically insulating) material. For example the flexible substrate film may be a polyimide film or the like. The flexible PCB may further comprise one or more conductive traces on a surface of the substrate film, formed of a conductive material such as copper or the like. In some cases, a protective (insulating) coating may be arranged to cover the conductive traces. Additionally, one or more electrical and / or electronic components may be mounted on the flexible PCB such that they are connected to the conductive traces.

[0134] The flexible printed circuit board is disposed in a brow portion of the frame. This facilitates integrating electrical or electronic components of the protective goggles to be located in the brow portion, as well as providing connections between components located in side wing portions of the frame. For example, the flexible PCB may extend across the brow portion between a first (e.g. left-hand) side portion of the frame and a second (e.g. right-hand) side portion of the frame, to electrically connect a component (e.g. power source, controller) in the first side wing portion to a component (e.g. air flow source) in the second side wing portion.

[0135] The flexible PCB may be located in a groove or channel formed in the brow portion of the frame. In some cases, the frame may comprise a plurality of protrusions arranged to pass through corresponding apertures in the flexible PCB, in order to locate the flexible PCB relative to the frame and retain it in the frame. The protrusions can, for example, be barbed, so that the flexible PCB is reliably retained on the protrusions.

[0136] The air flow source may be a first air flow source arranged in a first side wing portion of the frame at a first end of the brow portion, the first air flow source being configured to generate a first air flow into the ocular space, and wherein a first end of the printed circuit board is connected to the first air flow source; and the protective goggles may further comprise a second air flow source arranged in a second side wing portion of the frame at a second end of the brow portion, the second air flow source being configured to generate a second air flow air flow into the ocular space, wherein a second end of the flexible printed circuit board is connected to the second air flow source. In this manner, an air flow source can be arranged on either side of the protective goggles, such that in use the air flow sources are disposed on either side of the wearer’s face. The flexible PCB extends across the brow portion so that ends of the flexible PCB are connected to the first and second air flow sources, respectively. In this manner, the same PCB can be used for powering and controlling both air flow sources, thus making the protective goggles more lightweight and compact. For example, a common set of power and control electronics can be connected to the flexible PCB, to control the air flow sources located in the two side wings of the frame. Further, providing air flow sources in either side of the frame contributes to making air flow in the ocular space more evenly distributed, as discussed in relation to the second aspect of the invention.

[0137] The first end of the flexible PCB may extend into the first side wing portion of the frame, to connect to the first air flow source. Similarly, the second end of the flexible PCB may extend into the second side wing portion of the frame to connect to the second air flow source.

[0138] The first air flow source may be located in a first cavity defined in the first (e.g. left-hand side) side wing of the frame, and the second air flow source may be located in a second cavity defined in the second (e.g. right-hand side) side wing of the frame.

[0139] The protective goggles may further comprise a first battery connected to the flexible printed circuit board in the first side wing portion. In this manner, the first battery can be housed together with the first air flow source in the first side wing portion of the frame. The first battery can be connected to the first end of the flexible PCB. The first battery can be configured to power the first air flow source. For example, the first battery may be connected to the first air flow source via the flexible PCB and / or another PCB located in the first side wing portion of the frame. In some cases, the first battery can be configured to power both the first and second air flow sources. For example, the first battery may be connected to the second air flow source via the flexible PCB.

[0140] Similarly, the protective goggles may further comprise a second battery connected to the flexible printed circuit board in the second side wing portion. In this manner, the second battery can be housed together with the second air flow source in the second side wing portion of the frame. The second battery can be connected to the second end of the flexible PCB. The second battery can be configured to power the second air flow source. For example, the second battery may be connected to the second air flow source via the flexible PCB and / or another PCB located in the second side wing portion of the frame. In some cases, the second battery can be configured to power both the first and second air flow sources. For example, the second battery may be connected to the first air flow source via the flexible PCB.

[0141] The first battery and / or the second battery may be a rechargeable battery.

[0142] The first air flow source may be mounted on a first rigid printed circuit board connected to the first end of the flexible printed circuit board. In this manner, the first rigid PCB can act as a support for the first air flow source and electronic components associated with the first air flow source. For example, one or more power control electronics may be provided on the first rigid PCB for controlling supply of power to the first air flow source. The first rigid PCB may be more rigid than the flexible PCB. This may ensure that a position of the first air flow source remains fixed within the side wing portion of the frame. The material of the first rigid PCB may be more rigid (e.g. have a greater hardness) than a material of the frame.

[0143] Similarly, the second air flow source may be mounted on a second rigid printed circuit board connected to the second end of the flexible printed circuit board. In this manner, the second rigid PCB can act as a support for the second air flow source and electronic components associated with the second air flow source. For example, one or more power control electronics may be provided on the second rigid PCB for controlling supply of power to the second air flow source. Similarly to the first rigid PCB, the second rigid PCB may be more rigid than the flexible PCB. This may ensure that a position of the second air flow source remains fixed within the side wing portion of the frame. The material of the second rigid PCB may be more rigid (e.g. have a greater hardness) than a material of the frame.

[0144] A first housing may be disposed in the first side wing portion of the frame, the first housing being arranged to at least partially enclose the first air flow source and one or more electronic components. In this manner, a common structure (i.e. the first housing) can serve to protect and provide mounting points for the air flow source and electronic components in the first side wing portion of the frame. For example, the first housing may comprise a first shroud which is arranged to at least partially cover the first air flow source and the one or more electronic components. The first housing can be arranged in the first cavity in first side wing portion of the frame mentioned above. Where a first rigid PCB is provided, the first housing may be connected to the first rigid PCB, to form a cover around electronic components of the first rigid PCB. The first housing may be formed of a material having a greater hardness (rigidity) than the material of the frame.

[0145] Similarly, a second housing may be disposed in the second side wing portion of the frame, the second housing being arranged to at least partially enclose the second air flow source and one or more electronic components. In this manner, a common structure (i.e. the second housing) can serve to protect and provide mounting points for the air flow source and electronic components in the second side wing portion of the frame. For example, the second housing may comprise a first shroud which is arranged to at least partially cover the second air flow source and the one or more electronic components. The second housing can be arranged in the second cavity in first side wing portion of the frame mentioned above. Where a second rigid PCB is provided, the second housing may be connected to the first rigid PCB, to form a cover around electronic components of the second rigid PCB. The second housing may be formed of a material having a greater hardness (rigidity) than the material of the frame.

[0146] Flexibility in the brow portion of the frame is advantageous, as this can facilitate flexing of the frame to conform to a curvature of the wearer’s face. In contrast, such flexibility may not be needed in the side wing portions of the frame. Thus, placing more rigid components such as the rigid PCBs, housings and air flow sources in the side wing portions allows integration of these components into the protective goggles without hindering the desired flexibility of the brow portion.

[0147] Where the flexible PCB is located in the brow portion, the flexible PCB may have an elongate shape so as to fit in the brow portion.

[0148] The protective goggles may further comprise a support board on which one or more electronic components are mounted, the support board being located in the brow portion of the frame and connected to the flexible printed circuit board. This facilitates mounting of electronic components in the brow portion of the frame. For example, the electronic components on the support board could include one or more sensors (e.g. any of the sensors mentioned in relation to the first or second aspect of the invention), components of a feedback system (discussed further below), and / or a tag reader for reading a tag on a filter (discussed further below).

[0149] The support board may be arranged to be centrally located in the brow portion, e.g. such that it is substantially centred between the first and second side wing portions of the frame. Positioning the support board generally central of the brow portion contributes to more even weight distribution across the protective goggles, thus improving comfort for the wearer.

[0150] The invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided.

[0151] Summary of the Figures

[0152] Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which:

[0153] Fig. 1 shows a schematic front view of protective goggles according to an embodiment of the invention;

[0154] Fig. 2 shows a schematic perspective view of the protective goggles;

[0155] Fig. 3 shows a front view of a frame and sealing arrangement of the protective goggles;

[0156] Fig. 4 shows a perspective view of the frame and sealing arrangement of the protective goggles; Fig. 5 shows a partial sectional view of the frame and sealing arrangement of the protective goggles;

[0157] Fig. 6 shows a schematic perspective view of an air flow source that may form part of the protective goggles;

[0158] Fig. 7 shows a schematic top view of an arrangement of a visor and first and second air flow sources of the protective goggles;

[0159] Fig. 8 shows a schematic front view of a reinforcing structure of the protective goggles;

[0160] Fig. 9 shows a schematic top view of the reinforcing structure;

[0161] Fig. 10 shows a schematic perspective view of a respirator according to an embodiment of the invention, the respirator including the protective goggles of Fig. 1 ;

[0162] Fig. 11 shows a schematic rear view of the respirator;

[0163] Fig. 12 shows a partial front view of the protective goggles;

[0164] Fig. 13 shows a partial front view of the protective goggles;

[0165] Fig. 14 shows a schematic perspective view of a filter for the protective goggles according to an embodiment of the invention;

[0166] Fig. 15 shows a schematic top view of a filter holder of the filter;

[0167] Fig. 16 shows a schematic top view of a lid of the filter holder;

[0168] Fig. 17 is a schematic front view of the protective goggles, illustrating air flow paths through the protective goggles;

[0169] Fig. 18 shows a schematic perspective view of an arrangement of electrical components in the protective goggles;

[0170] Fig. 18b shows a schematic perspective view of another arrangement of electrical components in the protective goggles;

[0171] Fig. 19 shows a schematic diagram showing electrical components included in the protective goggles, according to an embodiment of the invention; and

[0172] Fig. 20 shows a flow diagram of a method according to an embodiment of the invention.

[0173] Detailed Description of the Invention

[0174] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art.

[0175] Protective goggles 100 according to an embodiment of the invention are described with reference to Figs. 1 to 19. Fig. 1 shows a front view of the protective goggles 100, whilst Fig. 2 provides a perspective view showing an interior of the protective goggles 100. The protective goggles 100 are configured to protect a wearer’s eyes, and may be used as part of chemical, biological, radiological and nuclear (CBRN) personal protective equipment, i.e. the protective goggles 100 may be CBRN protective goggles. The protective goggles 100 include a frame 102 in which a visor 104 is mounted. The frame 102 is arranged to hold the visor 104 in front of the wearer’s eyes when in use, so that the wearer can see through the visor 104. The visor 104 is formed of a transparent or partially transparent material, e.g. polycarbonate or polyurethane. A sealing arrangement 106 is arranged on a rear side of the frame 102, and is configured to provide a substantially airtight barrier between the frame 102 and the face of a wearer when in use. The sealing arrangement 106 extends around an edge of the frame 102, in order to form a seal around the wearer’s eyes. The sealing arrangement includes a sealing surface (or strip) which is arranged to contact the wearer’s face in use, in order to form a seal against the wearer’s face (skin). The frame 102, visor 104 and sealing arrangement thus define an ocular space 108, which is a region enclosed by the protective goggles 100 around the wearer’s eyes when in use. Accordingly, the protective goggles 100 can prevent contaminants (e.g. dangerous gases, vapours, and / or airborne particles) from entering the ocular space 108, to protect the wearer’s eyes.

[0176] As described in more detail below, the protective goggles 100 includes a pair of air flow sources mounted in the frame 102, which are configured to generate an air flow into the ocular space 108. The air flow into the ocular space can provide a positive pressure in the ocular space 108, i.e. such that a pressure in the ocular space 108 is greater than a pressure of a surrounding atmosphere. This serves to prevent contaminants from entering the ocular space 108, e.g. via any leak between the sealing arrangement 106 and the wearer’s face. Additionally, the flow into the ocular space can act to defog an inner surface of the visor 104, to improve visibility through the visor 104.

[0177] In some embodiments, the frame 102 and the sealing arrangement 106 are integrally formed as a single piece of material. In particular, the frame 102 and the sealing arrangement 106 can be moulded as a single component, e.g. via a one-shot moulding process. For example, an injection moulding process can be used to produce the frame 102 and the sealing arrangement 106 as a single component. Fig. 3 shows a front view of the fame and sealing arrangement component on its own (i.e. without other components of the protective goggles), and Fig. 4 shows a perspective rear view of the frame and sealing arrangement component. The shape of the component including the frame 102 and sealing arrangement 106 can be entirely defined via the moulding process, such that no further processing of the frame 102 and sealing arrangement 106 may be needed for assembly of the protective goggles 100. In particular, a variety of features are defined in the frame 102 as part of the moulding process, in order to mount various components of the protective goggles 100 in the frame 102. The frame 102 and sealing arrangement 106 are made of a relatively flexible material, such as an elastomeric material having a Shore A hardness of 70 or less. Examples of suitable elastomeric materials include silicone, TPE, TPU, and butyl rubber.

[0178] Among the features defined in frame 102 is a groove (or channel) 110 for receiving an edge of the visor 104, such that the visor 104 can be fitted into groove 110 to mount the visor 104 in the frame 102. Thus, as shown in Fig. 1 , the frame 102 surrounds the visor 104.

[0179] In order to mount the air flow sources in the frame 102, a first cavity 112 and a second cavity 114 are defined in the frame. These are shown in Fig. 5, which provides a sectioned view of the frame and sealing arrangement component, taken along the plane 300 indicated in Fig. 3. The first cavity 112 is defined in a left-hand side portion (wing portion) 116 of the frame 102 which is located on a left-hand side of the frame 102, i.e. such that the left-hand side portion 116 is arranged on a left-hand side of the visor 104. The second cavity 114 is defined in a right-hand side portion (wing portion) 118 of the frame 102 which is located on a right-hand side of the frame 102, i.e. such that the right-hand side portion 118 is arranged on a right-hand side of the visor 104. The first cavity 112 is arranged (shaped) to receive a first air flow source, and the second cavity 114 is arranged (shaped) to receive a second air flow source. For example, a shape of the first cavity 112 may be complementary to a shape of the first air flow source (or of a housing containing the first air flow source), and a shape of the second cavity 114 may be complementary to a shape of the second air flow source (or of a housing containing the second air flow source).

[0180] A first aperture 130 is defined in the frame 102, to provide fluid communication between the first cavity 112 and the ocular space 108. The first aperture 130 is arranged for alignment with an outlet of the first air flow source, so that air can flow from the first air flow source into the ocular space 108. A second aperture 132 is defined in the frame 102, to provide fluid communication between the second cavity 114 and the ocular space. The second aperture 132 is arranged for alignment with an outlet of the second air flow source, so that air can flow from the second air flow source into the ocular space 108. Additionally, the frame 102 includes a first lip 134 arranged next to the first aperture 130, in order to retain the first air flow source in the first cavity 112. As the frame is formed of a relatively flexible material, the first air flow source can be push-fitted (inserted) into the first cavity 112, and held in place via friction with the frame 102 and by the first lip 134. Similarly, the frame 102 includes a second lip 136 arranged next to the second aperture 132, in order to retain the second air flow source in the second cavity 114. The second air flow source can be push-fitted (inserted) into the second cavity 114, and held in place via friction with the frame 102 and by the second lip 136.

[0181] An example of an air flow source 120 that can be mounted in the first cavity 112 and the second cavity 114 is shown in Fig. 6. As shown, the air flow source 120 includes a radial fan 122 which is mounted in a housing 124. A compartment 126 is connected to the housing 120 below the radial fan 122, in which a power source (e.g. battery) and / or circuitry associated with the radial fan 122 is contained. For example, a controller for controlling operation of the radial fan 122 may be located in the compartment 126. The housing 120 includes an outlet 128 via which an air flow generated by the radial fan 122 flows out of the housing 124. Additionally, an opening is formed in a sidewall of the housing 124 to expose an inlet 138 of the radial fan 122 located on a side of the radial fan 122, so that the radial fan 122 can draw in air via its inlet 138. The housing 124 and the compartment 126 may be integrally formed as a single piece of material, e.g. via a moulding process. The material of the housing 124 and the compartment 126 may have a greater hardness than the material of the frame. For example, the housing 124 and compartment 126 may be made of a relatively rigid plastic. Each of the first cavity 112 and the second cavity 114 is shaped to receive a respective air flow source arranged as air flow source 120. Thus, each of the first cavity 112 and the second cavity 114 may have a shape that is complementary to a shape of the air flow source 120, including the housing 124 and compartment 126.

[0182] Fig. 7 illustrates positions in which a first air flow source 120a and a second air flow source 120b are held by the frame 102 relative to the visor 104. A top view of the visor 104 and the first and second air flow sources 120a, 120b is shown in Fig. 7. For illustration purposes, other components of the protective goggles 100 such as the frame 102 are omitted from Fig. 7. The first and second air flow sources 120a, 120b correspond to the air flow source 120 described above. As can be seen, the frame 102 holds the first and second air flow sources 120a, 120b adjacent to the left-hand and right-hand sides of the visor respectively. The outlet 128 of the first air flow source 120a is aligned with the first aperture 134 in the frame, so that air exiting the first air flow source 120a enters the ocular space 108. The outlet 128 of the second air flow source 120b is alight with the second aperture 136, so that air exiting the second air flow source 120b enters the ocular space 108. In more detail, the first air flow source 120a is held so that an axis of rotation of its radial fan (indicated by the dashed line 140 in Fig. 7) is substantially normal to surface of the visor 104 adjacent to the first air flow source 120a, and the second air flow source 120b is held so that an axis of rotation of its radial fan (indicated by dashed line 142 in Fig. 7) is substantially normal to a surface of the visor 104 adjacent to the second air flow source 120b. In this manner, the air flows exiting the first and second air flow sources 120, 120b flows tangentially along the inner surface of the visor 104. The first air flow source 120a and the second air flow source 120b are arranged substantially symmetrically about a middle plane of the protective goggles 100.

[0183] In some cases, the compartment 126 of one or both of the first and second air flow sources 120a, 120b can contain a respective power source (e.g. battery) for powering the air flow sources. In some cases, the compartment 126 of one of the first and second air flow sources 120a, 120b may contain a power source (e.g. battery) for power both the first and second air flow sources 120a, 120b, and the compartment 126 of the other one of the first and second air flow sources 120a, 120b may contain control electronics (e.g. a controller) for controlling operation of the first and second air flow sources 120a, 120b.

[0184] The protective goggles 100 further include a reinforcing structure 148, which is shown on its own in Figs. 8 and 9. Fig. 8 shows a front view of the reinforcing structure 148, and Fig. 9 shows a top view of the reinforcing structure 148. The reinforcing structure 148 is integrally formed as a single piece of material, e.g. via a suitable moulding process. The reinforcing structure 148 is made of a material having a greater harness than the material of the frame 102, e.g. the material of the reinforcing structure 148 can have a Shore A hardness greater than 70. For example, the reinforcing structure 148 may be made of a thermoplastic, PA66, polycarbonate, polypropylene, or similar. The reinforcing structure 148 includes a first exhaust component 150 and a second exhaust component 152, which are connected via a bridge portion 154. The first exhaust component 150 is mounted in a first opening 144 defined in the frame 102, the first opening 144 being arranged to be located under the wearer’s left eye in use. The second exhaust component 152 is mounted in a second opening 146 defined in the frame 102, the second opening 146 being arranged to be located under the wearer’s right eye in use. The bridge portion 154 is shaped to pass over the wearer’s nose in use. The first opening 144 and the second opening 146 in the frame 102 are shown, for example, in Fig. 3. The first and second exhaust components 150, 152 include a series of tabs 156 which are configured to secure the first and second exhaust components 150, 152 in the first and second openings 144, 146, respectively.

[0185] Each of the first and second exhaust components 150, 152 includes a plurality of apertures 158, via which air can flow out of the ocular space 108. Thus, each of the first and second exhaust components 150, 152 defines a respective exhaust outlet of the protective goggles 110, via which air can flow out of the ocular space 108. In the example shown, the plurality of apertures 158 are circular or semi-circular. However, other shapes and arrangements of apertures can be used. The plurality of apertures 158 may further serve as drainage channels via which fluid (e.g. sweat or condensation) can exit the ocular space 108. Additionally or alternatively, one or more channels or grooves may be provided in the first and second exhaust components 150, 152 to guide (e.g. wick) fluid out of the ocular space 108. The first and second exhaust components 150, 152 may each further comprise a filter material (not shown), which is arranged to cover the plurality of apertures 158 to prevent ingress of contaminants via the plurality of apertures. In particular, each of the first and second exhaust components 150, 152 includes a sidewall surrounding the plurality of apertures, defining a space for holding a filter material. The filter material could include any suitable filter material, such as a foam, cloth or fabric filter material. The plurality of apertures 158 and filter material (if provided) can be arranged to provide a resistance to air flow out of the ocular space, e.g. to facilitate maintaining a positive pressure in the ocular space. For example, a number and / or size of the plurality of apertures 158 can be reduced to increase a resistance to air flow via the plurality of apertures 158. Additionally or alternatively, a thickness and / or density of the filter material in the first and second exhaust components 150, 152 can be increased to increase a resistance to air flow via the plurality of apertures 158.

[0186] As the reinforcing structure 148 is made of a material having a greater hardness than the frame 102 (i.e. such that the reinforcing structure 148 has a greater rigidity than the frame 102), the reinforcing structure 148 acts to reinforce the frame 102 and helps maintain a shape of the frame 102 during use. In particular, the relatively rigid first and second exhaust components 150, 152 can ensure that the first and second openings 144, 146 in the frame 102 remain open during use, to ensure that air can flow out of the ocular space 108 during use. Additionally, the bridge portion 154 acts to reinforce a bridge portion of the frame 102 which passes over the wearer’s nose.

[0187] The reinforcing structure 148 may further comprise a first connector 160 for detachably connecting a respirator mask. In the example shown, the first connector 160 includes a catch (e.g. loop or eyelet) which projects outwardly (i.e. forwards) from the frame 102. The connector 160 is configured for engagement with a corresponding connector on the mask. Connection between the protective goggles 100 and a mask 800 is illustrated in Figs. 10 and 11.

[0188] The mask 800 may be referred to as an oro-nasal mask, for example. The mask 800 is configured to filter ambient gas inhaled into the mask 800 by a person wearing the mask, to produce filtered gas for breathing by the wearer. The mask 800 can therefore protect the wearer from inhaling harmful substances in ambient air. In particular, the mask 800 can include one or more filters connected to the mask 800 that include a filtration medium, such as activated carbon, that filters ambient air (or other gas) inhaled into the mask 800 from outside the mask 800 by the wearer, to produce filtered air (or other filtered gas) for breathing. Such a mask 800 may be referred to as a filtration mask, for example. In embodiments, the mask 800 may preferably be a half-mask. In an alternative embodiment, the mask 800 may instead be connected to a source of breathable gas, for example a container or tank of breathable gas, which is typically pressurised (e.g., a container of compressed breathable gas), to supply gas to the mask 800, or an external air filter. The breathable gas may comprise filtered air. The gas in the mask 800 breathed in by the wearer may therefore be separate to and / or isolated from ambient gas / air on the outside of the mask 800.

[0189] The mask 800 is configured to form a seal around the nose and mouth of the person wearing the mask. The mask 800 comprises a second sealing arrangement 802 configured to form the seal around the nose and mouth of the person wearing the mask. In particular, the mask 800 comprises a rigid nose-cup 804 to define a cavity around the nose and mouth of the wearer, with the sealing arrangement 802 being arranged around the periphery of the cavity. The sealing arrangement 802 may be formed of a flexible elastomeric material, to form a substantially air-tight seal against the wearer’s skin. The mask 800 can be held in place over the nose and mouth of the wearer using one or more straps, for example one or more head straps. The mask 800 is configured to provide a sealed breathing cavity or space that extends from the top of the nose of the user to a point between the chin of the user and the mouth of the user. The mask 14 therefore has a similar geometry to a quarter mask. The sealed breathing cavity or space may be referred to as an oronasal cavity, for example.

[0190] The mask 800 may comprise an outlet valve or exhale valve that is configured to allow flow of gas in a direction from the inside of the mask to the surrounding environment and to prevent flow of gas in a direction from the surrounding environment to the inside of the mask. Therefore, air or gas breathed out by a user of the mask 800 can be discharged from the mask 800.

[0191] The protective goggles 100 and the mask 800 are provided as separate (i.e., modular) components which can be easily disconnected and connected to one another, and are in particular designed such that they can be easily disconnected and connected to one another while a user is wearing either of the protective goggles 100 or the mask 800. The mask comprises a second connector 806 which is configured to engage the first connector 160 on the protective goggles 100 to connect the mask 800 to the protective goggles 100. In the example shown, the second connector 806 comprises a hook which projects upwardly from the nose-cup 804 to engage the first connector 160. In particular, the hook is arranged to pass through the loop or eyelet provided by the first connector 160, to connect the mask 800 to the protective goggles 100. An opening of the hook faces at least partly downwards, so that, when the mask 800 is connected to the protective goggles 100, the mask 800 cannot be pulled downwards away from the protective goggles 100 without lifting and / or rotating the mask 800 to disconnect the mask 800 from the protective goggles 100. By being shaped in this way, the hook also ensures that the mask 800 may hang from the protective goggles 100 when attached, and also ensures fitment can only occur in one direction - that is, from beneath the protective goggles 100, between the wearer’s nose and the protective goggles 100. It will be appreciated that in other embodiments, the first connector 160 may be located on the mask 800, and the second connector 806 may be located on the protective goggles 100.

[0192] Together, the protective goggles 100 and the mask 800 form a respirator according to an embodiment of the invention. Fig. 10 shows a perspective view of the respirator, where the mask 800 is connected to the protective goggles 100. Fig. 11 provides a rear view of the respirator, showing an inside of the protective goggles 100 and the mask 800. As can be seen in Fig. 11 , the sealing arrangement 106 of the protective goggles 100 and the sealing arrangement 802 of the mask 800 overlap one another to form a continuous sealing surface which is arranged to extend around (or over) a bridge of the wearer’s nose, such that the continuous sealing surface extends from a left side of the wearer’s nose to a right side of the wearer’s nose. In this way, the sealing arrangements 106, 802 form a layered (overlapping) structure in the bridge region, to prevent leak paths between the sealing arrangements 106, 802. This provides additional protection to ensure that the ocular space 108 and space enclosed by the mask 800 are airtight.

[0193] The protective goggles 100 further comprise a strap 162 for securing the protective goggles 100 to the wearer’s head. For illustration purposes, parts of the strap 162 are shown in dashed lines in Figs. 1 and 13. The strap 162 may, for example comprise an elasticated band, which may have an adjustable length to fit different head sizes. The strap 162 is connected to projecting tabs 164 located on either side of the visor 104. In particular, the left-hand side and the right-hand side of the visor 104 each include a connection region from which the tabs 164 protrude. The tabs 164 are integrally formed as part of the visor 104. For example, the visor 104 may be moulded or otherwise machined to have the tabs 164. Fig. 12 shows a close-up front view of a left-hand side of part of the protective goggles 100. As can be seen, the tabs 164 protrude through apertures 166 in the frame 102, such that they protrude beyond an outer surface of the frame 102. In more detail the left hand side of the visor 104 includes a first tab 164a which protrudes from an upper edge of the visor 104, and a second tab 164b which protrudes from a lower edge in the frame 102, the tabs 164a, 164b protruding through respective apertures 166a, 166b in the frame. A corresponding tab arrangement is provided on the right-hand side of the visor 104. As shown in Fig. 13, a first connector part 168a which is arranged to sit over the left-hand side portion 116 of the frame is connected to the protruding tabs 164a, 164b, e.g. via a snap-fit connection. The first connector part 168a includes a loop (or eyelet) 170 to which an end of the strap 162 is attached. A second connector part 168b is similarly arranged to sit over the right-hand side portion 118 of the frame, and is connected to the protruding tabs 164 on the right-hand side of the visor 104, e.g. via a snap-fit connection. A second end of the strap 162 is connected to a loop (or eyelet) 172 on the second connector part 168b. Thus, the ends of the strap 162 are connected to the ends of the visor 104, via the first and second connector parts 168a, 168b. The first and second connector parts 168a, 168b are made of a material having a greater hardness than the material of the frame 102, e.g. having a Shore A hardness greater than 70. For example, the first and second connector pats 168a, 168b may be made of a relatively hard plastic. For illustration purposes, the first connector part 168a is omitted from Fig. 12.

[0194] The protective goggles 100 further include a filter 174 arranged in a brow portion 176 of the frame 102, the filter 174 being arranged to filter air drawn by the first air flow source 120a and the second air flow source 120b. In particular, a filter cavity 178 for receiving the filter 174 is formed in the brow portion 176, the filter cavity 178 extending along a width of the brow portion 176 between the right-hand side portion 116 and the left-hand side portion 118 of the frame 102. The filter 174 is removably mountable in the filter cavity 178, and may be retained in the filter cavity 178 by a push-fit connection and / or an interference fit with the cavity 178, for example. As can be seen in Fig. 4, for example, a first air flow passage 180 is defined in the left-hand side portion 116 of the frame 102 which fluidly connects a first end of the filter cavity 178 to the first cavity 112 in which the first air flow source 120a is located. Additionally, a second air flow passage 182 is defined in the right-hand side portion 118 of the frame 102 which fluidly connects a second end of the filter cavity 178 to the second cavity 114 in which the second air flow source 120b is located.

[0195] Fig. 14 shows a perspective view of the filter 174. The filter 174 includes a filter holder (or housing) 184 which is shaped to fit in the filter cavity 178. Thus, the filter holder 184 is curved, to match a curvature of the brow portion 176 of the frame 102. A top view of the filter holder 184 on its own is shown in Fig. 15. The filter holder 184 is formed of a material having a greater hardness than the material of the frame 102, e.g. having a Shore A hardness greater than 70. In some cases, the filter holder 184, reinforcing structure 148, and connector parts 168a, 168b may all be formed of a same or similar material. The filter holder 184 can include one or more engagement features on its outer surface to engage a surface of the filter cavity 178, to thereby retain the filter holder 184 in the filter cavity 178. For example, the outer surface of the filter holder 184 can include a lip and / or a barbed feature on its outer surface for retaining the filter holder 184 in the filter cavity 178.

[0196] The first end of the filter holder 184 has a first outlet 186 arranged over the left-hand side portion 116 of the frame 102 when the filter holder 184 is mounted in the filter cavity 178, such that the first outlet 186 is in fluid communication with the first air flow passage 180. The second end of the filter holder 184 has a second outlet 188 arranged over the right-hand side portion 118 of the frame 102 when the filter holder 184 is mounted in the filter cavity 178, such that the second outlet 188 is in fluid communication with the second air flow passage 182. The filter holder 184 contains a filter medium 190. The filter medium 190 fills an interior space of the filter holder 184, and covers the first outlet 186 and the second outlet 188. The filter medium 190 serves to filter air passing through the filter 174, to remove contaminants from the air. As an example, the filter medium 190 can include an activated carbon cloth or fabric, and / or a particulate filter material. The filter medium 190 is bonded to the filter holder 184, so that an airtight seal is formed between the filter material 190 and the filter holder 184.

[0197] The filter holder 184 includes a lid or cover 192, a top view of which is shown in Fig. 16. For illustration purposes, the filter holder 184 is shown without the cover in Fig. 14, so that the filter medium 190 can be seen. Likewise, the lid 192 is omitted from Fig. 15, so that the first and second outlets 186, 188 are visible in Fig. 15. The lid 192 defines an upper surface of the filter 174. Together, the lid 192 and the rest of the filter holder 184 enclose the filter material 190. The lid 192 includes a plurality of holes which define a plurality of air inlets 194 for the filter 174. As shown in Fig. 16, the plurality of air inlets 194 are arranged in order of decreasing size (e.g. width or diameter) from a middle of the filter 174 towards each end of the filter 174. In other words, starting from each end of the filter 174, the apertures increase in size towards the middle of the filter 174. In this way, air is preferentially drawn into the filter towards the middle of the filter 174. A similar effect can alternatively or additionally be achieved by increasing a frequency of the air inlets towards the middle of the filter 174.

[0198] Fig. 17 shows a front view of the protective goggles illustrating an air flow through the protective goggles 100, when in use. In use, the protective goggles 100 are positioned over the wearer’s eyes, and secured to the wearer’s head using the strap 162. The first air flow source 120a and the second air flow source 120b can then be activated. This causes air to be drawn into the filter 174 via the plurality of air inlets 194 defined in the lid 192 of the filter holder 184. Air flow into the filter is indicated by the arrows 200 in Fig. 17. Air flowing into the filter 174 is then drawn to the first outlet 186 of the filter 174 and through the first air flow passage 180 in the frame 102 by the first air flow source 120a, as shown by arrow 202. The air drawn by the first air flow source 120a is blown out via the outlet 128 of the first air flow source 120a into the ocular space 108, corresponding to a first air flow 204 into the ocular space 108. The first air flow 204 can then exit the ocular space 108 via the first exhaust outlet defined by the first exhaust component 150. Similarly, air flowing into the filter 174 is drawn to the second outlet 188 of the filter 174 and through the second air flow passage 182 in the frame 102 by the second air flow source 120b, as shown by arrow 206. The air drawn by the second air flow source 120b is blown out via the outlet 128 of the second air flow source 120b into the ocular space 108, corresponding to a second air flow 208 into the ocular space 108. The second air flow 208 can then exit the ocular space 108 via the second exhaust outlet defined by the second exhaust component 152.

[0199] The first air flow 204 and the second air flow 208 into the ocular space can create a positive pressure in the ocular space 108. Additionally, the first and second air flows 204, 208 can serve to remove moisture from the ocular space 108, to reduce condensation on the visor 104. Fig. 7 shows a direction of the first air flow 204 exiting the first air flow source 120a, and a direction of second air flow 208 exiting the second air flow source 120b. As can be seen, the first air flow 204 is incident on a left-hand portion of the inner surface of the visor 104, located in front of the wearer’s left eye in use. The second air flow 208 is incident on a right-hand portion of the inner surface of the visor 104, located in front of the wearer’s right eye in use. In this manner, the first and second air flows 204, 208 may serve to defog the first and second regions of the inner surface of the visor 104, respectively. In some cases, the outlet 128 of the first and second air flow sources 120a, 120b may be provided with a nozzle which is directed towards the first and second regions of the inner surface of the visor 104, respectively. This can facilitate directing the air flows onto regions of the inner surface of the visor 104 located in front of the wearer’s eyes, as well as accelerate the air flows which may enhance defogging of the visor 104.

[0200] In some embodiments, the filter 174 can include a tag 210 which includes information relating to the filter 174, and which can be used by the protective goggles 100 for controlling operation of the air flow sources 120a, 120b. For example, the tag 210 can include an electronic tag, such as an RFID tag, which is mounted in (disposed in) the filter holder 184 as indicated by the dashed lines in Fig. 15. Where the tag 210 is an electronic tag, the tag can have a memory storing information relating to the filter 174, and a communication module including an antenna for communicating the information stored in the memory. The protective goggles 100 can then include a tag reader 212 mounted in a brow portion of the frame 102, e.g. as shown by the dashed lines in Fig. 3. The tag reader 212 is configured to read the information stored in the memory of the tag 210 when the filter is mounted in the filter cavity 178. For example, the tag reader 212 may comprise an antenna configured to communicate with the communication module in the tag 210. A controller of the protective goggles 100 (e.g. the controller located in one of the compartments 126 mentioned above) is connected to the tag reader 212, and may be configured to control operation of the first and second air flow sources 120a, 120b based on information obtained from the tag 210 in the filter. Fig. 18 shows a schematic perspective view of an arrangement of the air flow sources 120a, 120b and associated circuitry in the protective goggles 100. As shown, the first air flow source 120a and the second air flow source 120b are connected via a flexible printed circuit board (PCB) 196. The flexible PCB 196 extends through the brow portion 176 of the frame 102, from the left-hand side portion 116 to the righthand side portion 118 of the frame 102. The flexible PCB 196 can be located in a groove or channel formed in the brow portion 176 of the frame, e.g. under the filter cavity 178. For illustration purposes, the frame 102, sealing arrangement 106 and visor 104 are not depicted in Fig. 18. The flexible PCB 196 includes a first end 198 which extends into the left-hand side portion 116 of the frame 102 to connect to the first air flow source 120a, and a second end 199 which extends into the right-hand side portion 118 of the frame 102 to connect to the second air flow source 120b. The flexible PCB 196 includes a flexible film made of a dielectric material, on which a plurality of conductive traces are carried. The conductive traces are arranged to provide electrical connections between the first and second air flow sources 120a, 120b and other components of the protective goggles 100, as described in more detail below.

[0201] Each of the first and second air flow sources 120a, 120b in Fig. 18 is configured as described above in relation to Fig. 6. Additionally, as shown in Fig. 18, the first air flow source 120a includes a first PCB 201 , on which its radial fan 122 is mounted. Likewise, the second air flow source 120b includes a second PCB 203, on which its radial fan 122 is mounted. The first end 198 of the flexible PCB 196 is connected to the first PCB 201 , and the second end 199 of the flexible PCB 196 is connected to the second PCB 203. In this manner, the flexible PCB can convey electrical signals between the first and second PCBs 201 , 203. The first and second PCBs 201 , 203 may also be referred to as rigid PCBs. The radial fan of the first air flow source 120a is electrically connected to the first PCB 201 , so that it can be controlled by, and receive power via, the rigid PCB 201. Additional electronic components may provided on the first PCB 201 , such as a controller for one or both of the air flow sources, and / or power electronics for controlling supply of power to the radial fan of the first air flow source 120a. Similarly, the radial fan of the second air flow source 120b is electrically connected to the second PCB 203, so that it can be controlled by, and receive power via, the second PCB 203. Additional electronic components may be provided on the second PCB 203 such as a controller for one or both of the air flow sources, and / or power electronics for controlling supply of power to the radial fan of the second air flow source 120b. The first and second PCBs 201 , 203 are more than the flexible PCB 196. In particular, the substrate of each of the first and second PCBs may have a substrate having a greater thickness and rigidity compared to the flexible film substrate of the flexible PCB 196. The housing 124 and compartment 126 of each of the first and second air flow sources 120a, 120b may be mounted to the first PCB 201 and the second PCB 203, respectively.

[0202] In some cases, a support board 205 may be connected to the flexible PCB 196, such that the support board 205 is located in the brow portion 176 of the frame 102 with the flexible PCB 196. The support board 205 may comprise a PCB on which one or more sensors of the protective goggles are mounted. In some cases, the tag reader 212 mentioned above may also be mounted on the support board 205. Additionally, an output device for a feedback system can be mounted on the support board 205, as described further below. The support board 205 can be mounted in the brow portion 176 of the frame 102 such that it is located towards a middle of the brow portion 176, e.g. such that it is substantially centred between the first air flow source 120a and the second air flow source 120b.

[0203] Fig. 18b shows an alternative arrangement for electronic circuitry in the protective goggles 100. In the arrangement of Fig. 18b, the first air flow source 120a and the second air flow source 120b are connected via a cable 400. The cable 400 extends through a lower portion of the frame 102, such that the cable 400 passes under the wearer’s eyes. In particular, the cable 400 passes through a bridge portion of the frame 102 which fits around the wearer’s nose. In other examples, the cable 400 may instead pass through the brow portion 176 of the frame 102, similarly to the flexible PCB discussed above. The cable 400 can be located in a groove or channel formed in the frame 102, so as not to get in the way of the wearer. For illustration purposes, the frame 102, sealing arrangement 106 and visor 104 are not depicted in Fig. 18b. The cable 400 is configured to convey electrical signals between the first and second PCBs 201 , 203, e.g. to provide synchronised control of the first and second air flow sources 120a, 120b. The cable 400 may carry one or more wires to provide required communication between the first and second PCBs 201 , 203. The first and second PCBs 201 , 203 may as described above in relation to Fig. 18. Any sensors provided in the protective goggles 100 may be connected to the first and / or second PCB via one or more wires arranged in the frame 102. Fig. 19 shows a schematic diagram of control circuitry in the protective goggles 100 according to an example embodiment. It should be noted that the architecture shown in Fig. 19 is not limited to being used with the specific arrangement of the protective goggles 100 described above, and that the functionality described in relation to Fig. 19 can be implemented in other arrangements of protective goggles. The protective goggles 100 include the controller 214 for controlling operation of the air flow sources 120a, 120b. The controller 214 may include any suitable processing or computing device for controlling the air flow sources 120a, 120b. The controller 214 may, for example, be provided on the first PCB 201 or on the second PCB described above. A power source 216 is connected to the controller 214, and arranged to power the controller 214, the air flow sources 120a, 120b, and any other electrical components of the protective goggles 100 in use. In particular, the power source 216 provides power to the fan of each of the first and second air flow sources 120a, 120b. For example, the power source 216 can include one or more batteries located in the compartment 126 of one or both of the air flow sources. Additionally or alternatively, a battery may be provided in the filter 174. For example, a battery may be mounted in the filter holder 184, the battery being arranged to power the air flow sources 120a, 120b when the filter 174 is mounted in the filter cavity 178. In such a case, electrical connectors may be provided in the filter cavity 178 and extend within the frame 102 to electrically connect the battery in the filter 174 to the air flow sources 120a, 120b and / or the controller 214 when the filter 174 is mounted in the filter cavity 178. The power source 216 can include a rechargeable battery, in which case the protective goggles may include a power connector for connecting the protective goggles to an external power source to charge the rechargeable battery. The controller 214, or another dedicated charging controller, may then be configured to control charging of the battery. In other cases, the protective goggles 100 may be configured for use with an external power supply. In such a case, the power source 216 may comprise a connector for connecting the protective goggles to the external power supply. For example, the external power supply could include a battery pack, e.g. mounted on the strap 162 of the protective goggles or on a helmet worn by the user. The controller 214 is configured to control an air flow rate provided by each of the first and second air flow sources 120a, 120b. For example, the controller 214 can control a speed of the radial fan of each air flow source. The controller 214 can control the air flow rate provided by each air flow source, for example, by controlling an amount of power supplied from the power source 216 to the fan.

[0204] The protective goggles 100 further include one or more sensors 218, which are configured to detect one or more conditions of the ocular space 108 in the protective goggles 100. The one or more sensors can include, for example, a temperature sensor 218a configured to detect a temperature in the ocular space 108, a pressure sensor 218b configured to detect a pressure in the ocular space 108, and / or a humidity sensor 218c configured to detect a humidity level in the ocular space 108. Additional types of sensors that can be included in the protective goggles include a flow rate sensor, for detecting an air flow rate of one or both of the air flow sources 120a, 120b, and a condensation sensor for detecting the formation of condensation in the ocular space 108. The one or more sensors 218 are mounted in the frame 102. For example, the one or more sensors 218 can be mounted on the support board 205, and arranged to protrude through an aperture in the frame 102 such that they are exposed to the ocular space 108. Where air flow sensors are used, a respective air flow sensor may be positioned at the outlet of each air flow source, in order to detect the air flow rate provided by each air flow source.

[0205] The one or more sensors 218 are connected to the controller 214, i.e. so that the controller 214 can receive a respective output signal from each of the one or more sensors 218. The controller 214 is configured to control operation of the air flow sources 120a, 120b based on the output signal(s) received from the one or more sensors 218. Various examples of using output signals from the sensors for controlling the air flow sources are provided below. The controller 214 is additionally connected to the tag reader 212 mentioned above, which is configured to read information from the tag 210 in the filter 174 when the filter 174 is mounted in the frame 102.

[0206] In some embodiments, the controller 214 is configured to control the first and second air flow sources 120a, 120b to provide a positive pressure in the ocular space 108. For example, the controller 214 may be configured control the first and second air flow sources 120a, 120b to maintain a target pressure. The target pressure could for instance be a predetermined pressure in the ocular space 108, and / or a predetermined pressure differential between the ocular space 108 and a surrounding atmosphere. The controller 214 is thus configured to use the output from the pressure sensor 218b in a feedback loop for controlling the first and second air flow sources 120a, 120b, in order to achieve and maintain the target pressure. For example, the controller 214 can compare the output signal from the pressure sensor 218b to the target pressure (or some other value associated with the target pressure), and adjust the flow rate of the first and second air flow sources 120a, 120b accordingly. Increasing the air flow rate may cause an increase in pressure in the ocular space 108, whilst decreasing the air flow rate may decrease the pressure in the ocular space 108. As an example, the controller 214 may be configured to use the output from the pressure sensor 218b as an input in a proportional-integral-derivative (PID) control loop for maintaining the target pressure.

[0207] Additionally or alternatively, the controller 214 can be configured to control the first and second air flow sources 120a, 120b to reduce a risk of condensation on the inner surface of the visor 104. This can be achieved in various ways. As an example, the controller 214 can use the output from the one or more sensors 218 to determine a risk of condensation forming on the inner surface of the visor 104, and control the air flow rate of the air flow sources to reduce the risk. The controller 214 may store a predetermined relationship between the output of the one or more sensors 218 and a risk of condensation forming on the visor, so that the controller 214 can determine the current risk of condensation based on the output from the one or more sensors 218. Indeed, the risk of condensation forming on the inner surface of the visor 104 will depend on factors such as temperature, pressure and humidity in the ocular space 108, such that these can all be used as indicators of a risk of condensation. In some cases, the controller 214 may be configured to calculate a dew point of the air in the ocular space 108 using the output(s) from the one or more sensors, to determine a risk of condensation forming on the inner surface of the visor 104. If the controller 214 determines, based on the output(s) from the one or more sensors that there is a high risk of condensation forming, the controller 214 may be configured to increase a flow rate of the first and second air flow sources 120a, 120b. Increasing the flow rate through the ocular space can contribute to removing moisture from the ocular space 108, as well as prevent moisture from settling on the inner surface of the visor 104. On the other hand, if the controller 214 determines that there is a relatively low risk of formation of condensation, the controller 214 may be configured to maintain a current air flow rate and / or reduce the air flow rate (e.g. in order to conserve battery power).

[0208] Where the one or more sensors 218 comprise a temperature sensor 218a, the controller 214 may be configured to compare an output of the temperature sensor 218a to a threshold value (e.g. a calculated or predetermined dew point). If the output of the temperature sensor 218a is below or within a predetermined range of the threshold value, then the controller 214 may be configured to increase the air flow rate (as this may be indicative of a high risk of condensation forming on the visor 104). Similar threshold comparisons may also be performed with the output of the pressure sensor 218b and / or the humidity sensor 218c. Where the one or more sensors 218 include a condensation sensor, the controller 214 may be configured to increase the flow rate when the output of the condensation sensor is indicative of formation of condensation in the ocular space 108.

[0209] In some cases, the protective goggles 100 may further include an external temperature sensor 218d which is configured to detect an ambient temperature of an atmosphere surrounding the protective goggles 100 (i.e. outside the ocular space 108). The external temperature sensor 218d is mounted in the frame 102, so as to be exposed to the surrounding atmosphere. The controller 214 may then be configured to control the air flow rate of the air flow sources 120a, 120b based on a comparison between the output from the temperature sensor 218a (which corresponds to an ‘internal’ temperature sensor) and an output from the external temperature sensor 218d. For example, if based on the comparison the controller 214 determines that the temperature in the ocular space 108 is below the ambient temperature, the controller 214 may be configured to increase the air flow rate (as this may be indicative of a high risk of condensation forming on the visor 104).

[0210] The tag 210 in the filter 174 can store various different types of information relating to the filter 174.

[0211] Examples of information that can be stored by the tag 210 include authentication information, filter identification, filter type, filter lifetime, date of manufacture, operating parameters to be used with the filter, or similar. Using the tag reader 212, the controller 214 is configured to obtain the information from the tag 210, and control operation of the fan based on (as a function of) the information obtained from the tag, e.g. using a set of predetermined rules stored in a memory of the controller 214. In some cases, the controller 214 may be configured to verify an authenticity of the filter based on authentication information stored in the tag 210. The controller 214 may then be configured to only activate the air flow sources 120a, 120b if the filter 174 is successfully authenticated based on the authentication information obtained from the tag 210. As another example, the controller 214 may be configured to control a fan speed (or flow rate) of the air flow sources 120a, 120b based on the information obtained from the tag 210. For example, the information stored in the tag 210 may include an indication of a fan speed which is to be used with that particular filter. Additionally or alternatively, different filter types (or filter identifiers) may be associated with different fan speeds in the memory of the controller 214, such that the controller 214 can select a fan speed based on a filter type determined from the information on the tag 210.

[0212] The controller 214 may further be configured to provide feedback to the wearer of the protective goggles about one or more operating conditions of the protective goggles 100. Thus, the protective goggles 100 can include an output device 220 which is configured to notify the wearer of the operating condition. The output device 220 can be mounted in the frame 102, so that it is located close to the wearer’s face in use, to provide effective notifications to the wearer. For example, the output device 220 may be mounted on, or connected to, the support board 205 discussed above. Together, the controller 214 and the output device 220 provide a feedback system for notifying the wearer of the operating condition.

[0213] The output device 220 can include various types of device capable of providing a notification (e.g. alert) to the wearer. In some cases, multiple types of output device may be combined in the protective goggles 100, e.g. to communicate different types of operating condition to the wearer. As an example, the output device 220 can include an optical output device, which is configured to generate a notification that is visible by the wearer in use. In particular, the optical output device is mounted in the frame so as to be within the wearer’s field of view when in use. For instance, the optical output device can be provided on the brow portion 176 of the frame. Alternatively, the optical output device can be provided in a portion of the frame which is arranged to be located under one of the wearer’s eyes in use. The optical output device can include one or more light sources (e.g. LEDs), and / or a display such as an LCD or the like. As another example, the output device 220 can include a device configured to output an audible notification, such as a speaker or beeper. As a further example, the output device 220 can include a haptic output device such as a vibration motor arranged in the frame 102, such that the wearer can sense vibrations generated by the haptic output device. The same output device may be used for notifying the wearer in relation to different operating conditions; alternatively, different output devices may be used in relation to different operating conditions. Where a display is used (e.g. LCD), this may facilitate notifying the wearer of multiple operating conditions at once.

[0214] In some cases, the controller 214 may be configured to provide feedback to the wearer based on parameters detected by any of the one or more sensors 218 mentioned above. For example, the controller 214 may be configured to detect a problem with the protective goggles 100 based on an output from the one or more sensors 218 and, if a problem is detected, the controller 214 causes the output device 220 to generate an alert to notify the wearer. For instance, the controller 214 can compare the output each of the one or more sensors 218 to a predetermined range associated with that sensor and, if the output falls outside the predetermined range, the controller 214 can generate an alert with the output device 220 to notify the wearer. Thus, for example, if the pressure in the ocular space 108 falls below a predetermined threshold (which may be indicative of a minimum safe positive pressure in the ocular space 108), the wearer can be immediately alerted. As another example, if the controller determines base on the output(s) from the one or more sensors 218 that there is a risk of condensation, the wearer can be alerted to this fact. As a further example, if the controller 214 determines that the air flow rate from one of the air flow sources falls below a predetermined threshold (e.g. based on an output from an air flow sensor), the controller 214 can notify the wearer via the output device 220. Thus, the controller 214 can continuously monitor the output(s) from the one or more sensors 218, and notify the wearer when the output falls outside of a predetermined range.

[0215] The controller 214 can also use the output device 220 to notify the wearer about a remaining power level of the battery (power source) 216. For example, the output device 220 may be configured to provide an indication of remaining power level in the battery. In some cases, the controller 214 may be configured to generate an alert with the output device 220 when the power level of the battery falls below a predetermined threshold.

[0216] The controller 214 may be configured to continuously provide an indication of an operating condition of the protective goggles 100 via the output device 220, so that the wearer is constantly informed about operation of the protective goggles 100. Alternatively, the controller 214 may be configured to only generate an alert when an issue with an operating parameter is detected. This may avoid distracting the wearer.

[0217] Returning to the filter 174 discussed above, an indication of filter lifetime can be stored in the tag 210. The controller 214 may be configured to monitor a usage time of the filter 174, i.e. an amount of time the air flow sources 120a, 120b are in operation whilst the filter 174 is mounted in the frame 102. If the usage time of the filter 174 exceeds the filter lifetime indicated in the tag 210, the controller 214 may be configured to generate an alert via the output device 220 to notify the user that the filter 174 should be replaced. If the tag 210 is an electronic tag, when the controller 214 determines that the lifetime of the filter 174 has been exceeded, the controller 214 may be configured to update the information stored in the tag 210 to include an indication that the filter 174 is used. For example, the tag reader 212 may be configured to communicate with the tag 210 to update the information stored in the memory of the tag 210. In this manner, the next time the tag reader 212 reads the tag 210, it can determine based on the information stored in the tag 210 that the filter is used 174 and should be changed. If the tag 210 of a filter 174 indicates that the filter 174 is used, the controller may be configured to generate an alert to notify the wearer that the filter should be changed, and / or the controller 214 may prevent the air flow sources 120a, 120b from being activated when the used filter is mounted.

[0218] The protective goggles 100 may comprise a first air flow source sensor 222a for detecting an operating condition of the first air flow source 120a and / or a second air flow source sensor 222b for detecting an operating condition of the second air flow source 120b. For example, the air flow source sensors 222a, 222b may be speed sensors (such as tachometers) for detecting a speed of the first and second air flow source, respectively. As another example, the air flow source sensors 222a, 222b may be air flow rate sensors, for detecting an air flow rate of the first and second air flow source, respectively. The controller 214 is connected to receive an output signal from each of the first and second air flow source sensors 222a, 222b.

[0219] The controller 224 may be configured to control the output device 220 based on the output signal from the first air flow source sensor 222a, and / or based on the output signal from the second air flow source sensor 222b. In this manner, the wearer can be notified of a performance of the air flow sources. For example, the controller 214 may be configured to generate an alert with the output device 220 if the output signal from either of the first and second air flow source sensors 222a, 222b is outside a predetermined range.

[0220] The air flow source sensors 222a, 222b can be used to determine if the filter 174 is correctly mounted in the filter cavity 178 in the frame 102. In particular, an air flow resistance experienced by the first and second air flow sources 120a, 120b will depend on the presence of the filter 174. If the filter 174 is not mounted in the frame 102, or if the filter is incorrectly or partially mounted in the frame 102, the air flow sources 120a, 120b will experience a lower air flow resistance. Accordingly, if the output signal from the first or second air flow source sensor is indicative of a low air flow resistance, then the controller 214 can determine that the filter 174 is not correctly mounted in the frame 102. If the controller 214 determines that the filter 174 is not correctly mounted in the frame 102, the controller 214 is configured to control the output device 220 to notify the wearer (e.g. by generating an alert with the output device 220).

[0221] As an example, where the air flow source sensors 222a, 222b are speed sensors, the controller 214 may be configured to determine that filter 174 is not correctly mounted if a speed of the first and / or second air flow source 120a, 120b is below a predetermined threshold. Indeed, a low air flow source speed may be indicative of a low air flow resistance, which may result from the filter 174 not being properly mounted. Additionally or alternatively, the controller 214 may be configured to determine an air flow resistance for the first air flow source and / or the second air flow source, as a function of the output signal form the first air flow source sensor 222a and the second air flow source sensor 222b, respectively. If the air flow resistance for the first air flow source and / or the second air flow source is below a predetermined threshold, the controller 214 may be configured to determine that the filter 174 is not correctly mounted in the frame 102. To determine the air flow resistance, a predetermined relationship between the output of the air flow source sensor 222a and / or 222b and air flow resistance may be stored in a memory of the controller 214. The predetermined relationship may be obtained from speed measurements performed with the first and / or second air flow source 120a, 120b for different levels of air flow resistance, and / or from a theoretical model for the air flow through the protective goggles 100.

[0222] As a further example, where the air flow source sensors 222a, 222b are air flow rate sensors, the controller 214 may be configured to determine that filter 174 is not correctly mounted if an air flow rate of the first and / or second air flow source 120a, 120b exceeds a predetermined threshold. Indeed, a high air flow rate may be indicative of a low air flow resistance, which may result from the filter 174 not being properly mounted. Although the example shown in Fig. 19 includes an air flow source sensor for each air flow source, in other examples only one of the air flow sources may be provided with a sensor.

[0223] As noted above, multiple types of output device may be combined in the protective goggles 100. For example, the output device 220 may comprise an optical output device (e.g. LED and / or display), a haptic output device, and / or an audible output device (e.g. a speaker or beeper). Where the output device 220 comprises multiple types of output device, the protective goggles may comprise a selection interface (not shown) to allow the wearer to select one of the output devices. For example, the selection interface may comprise a button, toggle, switch or other suitable interface, to allow the wearer to select one of the output devices. The selection interface may, for example, be located on an outer surface of the frame 102, so that it is accessible when wearing the protective goggles 100. The selection interface may be connected to the controller 214, so that the controller 214 can receive a selection of one of the output devices from the wearer. Then, the controller 214 can control the selected output device to notify or alert the wearer, in line with the above discussion.

[0224] It should be noted that the functions described above in relation to the controller 214 may be implemented via a single control device, or the functions may be distributed across multiple control devices which work together to perform the operations described.

[0225] Fig. 20 shows a flow diagram illustrating a method 2000 of operating protective goggles according to an embodiment of the invention. For convenience, the method 2000 will be described in the context of the protective goggles 100. The steps of method 2000 may correspond to control steps performed by the controller 214 of the protective goggles 100. In a first step 2002, an air flow into the ocular space 108 is generated. For example, the controller 214 controls the first and second air flow sources 120a, 120b to generate respective air flows into the ocular space 108. In a second step 2004, a condition of the ocular space 108 is detect. For example, the controller 214 can receive an output signal from the one or more sensors 218. In a third step 2006, the air flow rate into the ocular space 108 is controller based on (as a function of) the detected condition. This can include any of the examples of control described above in relation to the controller 214.

[0226] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0227] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

[0228] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations. Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0229] Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0230] It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / - 10%.

[0231] Additional aspects and / or embodiments of the present invention are set out in the following sets of numbered clauses. The section headings below are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0232] 1. Protective goggles comprising: a frame; a sealing arrangement configured to provide a seal between the frame and a face of a wearer; a visor connected to the frame; an air flow source configured to generate an air flow into an ocular space defined by the protective goggles; a sensor configured to detect a condition of the ocular space; and a controller configured to control an air flow rate of the air flow source based on an output from the sensor.

[0233] 2. Protective goggles according to clause 1 , wherein the output of the sensor is indicative of a risk of condensation on an inner surface of the visor.

[0234] 3. Protective goggles according to clause 2, wherein the controller is configured to determine a risk of condensation on the inner surface of the visor based on the output from the sensor, the controller being configured to control the air flow rate of the air flow source as a function of the determined risk of condensation.

[0235] 4. Protective goggles according to any preceding clause, wherein the sensor comprises a temperature sensor for detecting a temperature in the ocular space. 5. Protective goggles according to any preceding clause, wherein the sensor comprises a humidity sensor for detecting a humidity level in the ocular space.

[0236] 6. Protective goggles according to any preceding clause, wherein the sensor comprises a condensation sensor, for detecting condensation in the ocular space.

[0237] 7. Protective goggles according to any preceding clause, wherein the output of the sensor is indicative of an air pressure in the ocular space.

[0238] 8. Protective goggles according to clause 7, wherein the sensor is configured to detect the air flow rate and / or a current draw of the air flow source to provide the output indicative of pressure in the ocular space.

[0239] 9. Protective goggles according to any preceding clause, wherein the air flow source comprises a radial fan.

[0240] 10. Protective goggles according to any preceding clause, wherein the air flow source is configured to direct the air flow onto at least a portion of an inner surface of the visor.

[0241] 11. Protective goggles according to clause 10, wherein the outlet of the air flow source comprises a nozzle for directing the air flow onto the portion of the inner surface of the visor.

[0242] 12. Protective goggles according to any preceding clause, wherein the frame comprises one or more exhaust outlets to allow air to flow out of the ocular space.

[0243] 14. Protective goggles according to clause 12, wherein the one or more exhaust outlets comprise a first exhaust outlet arranged to be located under a left eye of the wearer, and a second exhaust outlet arranged to be located under a right eye of the wearer.

[0244] 15. Protective goggles according to clause 12 or 13, wherein each of the one or more exhaust outlets comprises a plurality of apertures, and a filter material covering the plurality of apertures.

[0245] 16. Protective goggles according to any preceding clause, wherein the air flow source is a first air flow source arranged in a first side wing portion of the frame, the first air flow source being configured to generate a first air flow into the ocular space; and wherein the protective goggles further comprise: a second air flow source arranged in a second side wing portion of the frame, the second air flow source being configured to generate a second air flow air flow into the ocular space; and wherein the controller is configured to control an air flow rate of the first air flow source and an air flow rate of the second air flow source based on an output from the sensor. 17. Protective goggles according to clause 16, further comprising an air intake defined in a brow portion of the frame, wherein the first air flow source and the second air flow source are each configured to draw air from the air intake to generate the first air flow and the second air flow, respectively.

[0246] 18. Protective goggles according to clause 17, wherein the air intake comprises a filter mounted in the brow portion of the frame, the filter being arranged to filter air drawn via the air intake.

[0247] 19. Protective goggles according to clause 18, wherein the filter comprises one or more air inlets, a first air outlet arranged towards a first end of the filter and in fluid communication with the first air flow source, and a second air outlet arranged towards a second end of the filter and in fluid communication with the second air flow source.

[0248] 20. Protective goggles according to any one of clauses 16 to 19, wherein a first air flow channel defined in the frame fluidly connects the air intake to the first air flow source, and a second air flow channel defined in the frame fluidly connects the air intake to the second air flow source.

[0249] 21. A method of operating protective goggles, the protective goggles comprising a frame, a sealing arrangement configured to provide a seal between the frame and a face of a wearer, a visor connected to the frame, and an air flow source configured to generate an air flow into an ocular space defined by the protective goggles, wherein the method comprises: detecting with a sensor of the protective goggles, a condition of the ocular space; and controlling an air flow rate of the air flow source based on an output from the sensor.

[0250] 2. _ Electronics Integration

[0251] 1. Protective goggles comprising: a frame; a sealing arrangement configured to provide a seal between the frame and a face of a wearer; a visor connected to the frame; an air flow source mounted in the frame and configured to generate an air flow into an ocular space defined by the protective goggles; and a flexible printed circuit board disposed in the frame, the flexible printed circuit board being connected to the air flow source.

[0252] 2. Protective goggles according to clause 1, wherein the flexible printed circuit board is disposed in a brow portion of the frame.

[0253] 3. Protective goggles according to clause 2, wherein the air flow source is a first air flow source arranged in a first side wing portion of the frame at a first end of the brow portion, the first air flow source being configured to generate a first air flow into the ocular space, and wherein a first end of the printed circuit board is connected to the first air flow source; and wherein the protective goggles further comprise a second air flow source arranged in a second side wing portion of the frame at a second end of the brow portion, the second air flow source being configured to generate a second air flow air flow into the ocular space, wherein a second end of the flexible printed circuit board is connected to the second air flow source.

[0254] 4. Protective goggles according to clause 3, further comprising a first battery connected to the flexible printed circuit board in the first side wing portion and / or a second battery connected to the flexible printed circuit board in the second side wing portion.

[0255] 5. Protective goggles according to clause 3 or 4, wherein the first air flow source is mounted on a first rigid printed circuit board connected to the first end of the flexible printed circuit board, and / or wherein the second air flow source is mounted on a second rigid printed circuit board connected to the second end of the flexible printed circuit board.

[0256] 6. Protective goggles according to any one of clauses 3 to 5, wherein a first housing is disposed in the first side wing portion of the frame, the first housing being arranged to at least partially enclose the first air flow source and one or more electronic components, and / or wherein a second housing is disposed in the second side wing portion of the frame, the second housing being arranged to at least partially enclose the second air flow source and one or more electronic components.

[0257] 7. Protective goggles according to any one of clauses 3 to 6, further comprising a support board on which one or more electronic components are mounted, the support board being located in the brow portion of the frame and connected to the flexible printed circuit board.

[0258] 8. Protective goggles according to any preceding clause, wherein the frame is formed of an elastomeric material.

[0259] 9. Protective goggles according to clause 8, wherein the elastomeric material has a Shore A hardness of 70 or less.

[0260] 10. Protective goggles according to any preceding clause, wherein the sealing arrangement and the frame are integrally formed as a single piece of material.

[0261] 3, _ Goggle Notifications

[0262] 1. Protective goggles comprising: a frame; a sealing arrangement configured to provide a seal between the frame and a face of a wearer; a visor connected to the frame; an air flow source configured to generate an air flow into an ocular space defined by the protective goggles; and a feedback system comprising an output device, wherein the feedback system is configured to control the output device to notify the wearer of an operating condition of the protective goggles.

[0263] 2. Protective goggles according to clause 1 , wherein the feedback system configured to detect an operating condition of the air flow source and control the output device based on the operating condition of the air flow source.

[0264] 3. Protective goggles according to clause 1 or 2, wherein the protective goggles further comprise a battery, and the feedback system configured to detect an operating condition of the battery and control the output device based on the operating condition of the battery.

[0265] 4. Protective goggles according to any preceding clause, wherein the protective goggles further comprise a sensor configured to detect a condition of the ocular space, wherein the feedback system is configured to provide feedback to a wearer based on the detected condition of the ocular space.

[0266] 5. Protective goggles according to any preceding clause, wherein the protective goggles further comprise a filter configured to filter air in the air flow generated by the air flow source, the feedback system is configured to detect an operating condition of the filter and to control the output device based on the operating condition of the filter.

[0267] 6. Protective goggles according to clause 5, wherein: the filter is removably mounted in a cavity defined in the frame; the filter comprises a tag, and the feedback system comprises a tag reader configured to obtain information from the tag when the filter is mounted in the cavity; the feedback system is configured to determine a filter lifetime based on the information obtained from the tag; the feedback system is configured to control the output device to notify the wearer when a usage time of the filter exceeds the determined filter lifetime.

[0268] 7. Protective goggles according to any preceding clause, wherein the output device comprises an optical output device.

[0269] 8. Protective goggles according to any preceding clause, wherein the output device comprises haptic output device.

[0270] 9. Protective goggles according to any preceding clause, wherein the output device is configured to output an audible notification.

Claims

Claims:

1. Protective goggles comprising: a frame; a sealing arrangement configured to provide a seal between the frame and a face of a wearer; a visor connected to the frame; an air flow source configured to generate an air flow into an ocular space defined by the protective goggles; and a feedback system comprising an output device, wherein the feedback system is configured to control the output device to notify the wearer of an operating condition of the protective goggles.

2. Protective goggles according to claim 1 , wherein the feedback system is configured to detect an operating condition of the air flow source and control the output device based on the operating condition of the air flow source.

3. Protective goggles according to claim 2, wherein the operating condition of the air flow source comprises a speed of the air flow source.

4. Protective goggles according to any preceding claim, wherein the protective goggles further comprise a filter configured to filter air in the air flow generated by the air flow source.

5. Protective goggles according to claim 4 and claim 2 or 3, wherein: the filter is removably mounted in the frame; the feedback system is configured to determine, based on the detected operating condition of the air flow source, whether the filter is correctly mounted in the frame, and to generate a notification with the output device if it is determined that the filter is not correctly mounted in the frame.

6. Protective goggles according to claim 4 or 5, wherein: the filter is removably mounted in a cavity defined in the frame; the filter comprises a tag, and the feedback system comprises a tag reader configured to obtain information from the tag when the filter is mounted in the cavity; the feedback system is configured to determine a filter lifetime based on the information obtained from the tag; the feedback system is configured to control the output device to notify the wearer when a usage time of the filter exceeds the determined filter lifetime.

7. Protective goggles according to any of claims 4 to 6, wherein the feedback system is configured to detect an operating condition of the filter and to control the output device based on the operating condition of the filter.

8. Protective goggles according to any preceding claim, wherein the protective goggles further comprise a battery, and the feedback system is configured to detect an operating condition of the battery and control the output device based on the operating condition of the battery.

9. Protective goggles according to any preceding claim, wherein the protective goggles further comprise a sensor configured to detect a condition of the ocular space, wherein the feedback system is configured to provide feedback to a wearer based on the detected condition of the ocular space.

10. Protective goggles according to any preceding clause, wherein the output device comprises one or more of: an optical output device; a haptic output device; and an output device configured to output an audible notification.

11. Protective goggles comprising: a frame; a sealing arrangement configured to provide a seal between the frame and a face of a wearer; a visor connected to the frame; an air flow source configured to generate an air flow into an ocular space defined by the protective goggles; a sensor configured to detect a condition of the ocular space; and a controller configured to control an air flow rate of the air flow source based on an output from the sensor.

12. Protective goggles according to claim 11, wherein the output of the sensor is indicative of a risk of condensation on an inner surface of the visor.

13. Protective goggles according to claim 12, wherein the controller is configured to determine a risk of condensation on the inner surface of the visor based on the output from the sensor, the controller being configured to control the air flow rate of the air flow source as a function of the determined risk of condensation.

14. Protective goggles according to any preceding claim, wherein the air flow source is configured to direct the air flow onto at least a portion of an inner surface of the visor; and optionally wherein an outlet of the air flow source comprises a nozzle for directing the air flow onto the portion of the inner surface of the visor.

15. Protective goggles according to any preceding claim, wherein the frame comprises one or more exhaust outlets to allow air to flow out of the ocular space; and optionally wherein the one or more exhaust outlets comprise a first exhaust outlet arranged to be located under a left eye of the wearer, and a second exhaust outlet arranged to be located under a right eye of the wearer.

16. Protective goggles according to any preceding claim, wherein the air flow source is a first air flow source arranged in a first side wing portion of the frame, the first air flow source being configured to generate a first air flow into the ocular space; and wherein the protective goggles further comprise: a second air flow source arranged in a second side wing portion of the frame, the second air flow source being configured to generate a second air flow air flow into the ocular space; and wherein the controller is configured to control an air flow rate of the first air flow source and an air flow rate of the second air flow source based on an output from the sensor.

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