GB2606578A

GB2606578A - Portable apparatus for providing a radiation dose to a target

Info

Publication number: GB2606578A
Application number: GB2106948.9A
Authority: GB
Inventors: Stevenson Matthew; Hearn Simon; Timms Craig
Original assignee: SENEYE Ltd
Current assignee: SENEYE Ltd
Priority date: 2021-05-14
Filing date: 2021-05-14
Publication date: 2022-11-16
Also published as: WO2022238551A1; GB202106948D0

Abstract

A portable apparatus for providing a radiation dose 6 to a target 1, the apparatus comprising: a radiation emitting device 8, a ranging device (9, fig. 4), and a processor (14, fig. 4). The processor (14, fig. 4) is configured to determine a distance between the apparatus and the target 1 based on range data obtained by the ranging device (9, fig. 4), a time duration for which radiation 6 emitted by the radiation emitting device 8 is incident on the target 1, and a radiant exposure at the target using the determined distance and determined time duration. The apparatus may further comprise a movement sensor (15, fig. 4) configured to detect at least one of an orientation, speed and/or an acceleration of the apparatus. In one embodiment, the apparatus further comprises a liquid sensor to detect whether the apparatus is submerged in liquid. The portable apparatus can be part of a device for sterilising surfaces, for destroying unwanted aquatic organisms or for curing materials by radiation.

Description

PORTABLE APPARATUS FOR PROVIDING A RADIATION DOSE TO A TARGET

TECHNICAL FIELD

This disclosure relates to a portable apparatus for providing a radiation dose to a target, in particular, although not exclusively, for sterilising surfaces, destroying unwanted aquatic organisms, and/or curing materials.

BACKGROUND

Destruction of unwanted biological organisms (such as viruses, algae, bacteria, or stinging anemones) is required for the sterilisation of surfaces and for the maintenance of aquariums. When used on surfaces, wipes and cleaning solutions are often unable to reach into deep cracks or shadow areas. Fogging solutions work better in respect of the hard-to-reach areas but leave surfaces wet and are not compatible with electronic items such as computer keyboards, and the airborne chemicals used can exacerbate respiratory problems. Furthermore, the use of chemicals is challenging in an aqueous solution, such as an aquarium, and often nonselective.

As an alternative to chemical treatments, sterilisation by radiation, such as ultraviolet (UV) radiation, has been shown to be highly effective. The use of UV-C radiation in clinical applications is increasing rapidly and its ability to neutralise both viruses and bacteria are well documented. At present most of the radiation used is delivered via fixed lamps which can create shadows. This issue can be addressed by employing a handheld lamp that can move and change axis, but ensuring an adequate radiation dose using such a device is challenging. Simply waving an unknown UV-C light at a target will not guarantee sterilisation. The dose needs to be controlled which is difficult when the device aimed at the target is not fixed in space. It is further complicated in that a user needs knowledge of the different exposure times required and needs to match that to the output of the torch to get the correct dose. In addition, humans are not very good at accurately judging distance or time, which are both factors that determine the delivered dose. If an organism is closer to the source emitter, a higher dose rate will be achieved in a shorter amount of time. The inverse square law teaches that even small changes in distance will make a large difference in exposure time required. Furthermore, user safety is an issue as UV-C radiation is very harmful to all organisms including humans and the eye is especially at risk.

SUMMARY

The present invention provides a portable apparatus for providing a radiation dose to a target in accordance with claim 1 appended hereto. Further advantageous embodiments are contained in the dependent claims, also appended hereto.

We describe a portable apparatus for providing a radiation dose to a target, the apparatus comprising: a radiation-emitting device; a ranging device; and a processor configured to determine a distance between the apparatus and the target based on range data obtained by the ranging device, and to determine a time duration for which radiation emitted by the radiation-emitting device is incident on the target; wherein the processor is further configured to determine a radiant exposure at the target using the determined distance between the apparatus and the target and the determined time duration.

The radiation emitted by the radiation-emitting device may be suitable for sterilising surfaces, destroying unwanted aquatic organisms, and/or curing materials (such as curable epoxies) by radiation. Accordingly, the target may be, for example, a surface to be sterilised, an aquatic organism, or a material for curing.

In order to ensure complete and effective destruction of a target organism, or curing of a target material, a minimum required radiation dose must be delivered to the target. For a given power emitted by a radiation source, the radiant exposure (also referred to as fluence) received at the target will depend on several factors, including the distance between the source and the target and the period of time over which the target is exposed to the radiation, for example a period of time for which the radiation-emitting device is active. Therefore, in contrast to known handheld radiation sources, the portable apparatus described herein advantageously enables monitoring of the radiant exposure at the target so that a user may be informed when the required radiation dose has been delivered to the target.

The portable apparatus described herein further advantageously enables feedback to be delivered to the user to indicate that the apparatus is, for example, too far away from the target to provide an effective radiation dose, or that the target has not been exposed to radiation for sufficient time. Feedback may be provided to the user as an audio or visual signal. For example, the apparatus may further comprise one or more visible light-emitting diodes (LEDs) for indicating to the user when the required radiation dose has been delivered. In some examples, the apparatus may be configured to transmit data to an external communications device, such as a personal computer or a smartphone, and feedback may be delivered to the user by software on the external communications device.

The portable apparatus may further comprise a movement sensor configured to detect at least one of an orientation, a speed, and/or an acceleration of the apparatus.

The movement sensor may comprise a microelectromechanical systems (MEMS) sensor.

The processor may be further configured to determine the time duration for which radiation emitted by the radiation-emitting device is incident on the target using the orientation of the apparatus.

The time duration for which radiation emitted by the radiation-emitting device is incident on a target may further depend on the amount of time for which the apparatus is maintained in an orientation such that the radiation is incident on the target. There may exist a range of orientations within which the radiation may be considered to be incident on the target, for example within which the target remains within a light cone of radiation emitted by the radiation-emitting device. Detecting the orientation of the apparatus advantageously provides further input data to enable the processor to determine the radiant exposure at the target to a higher accuracy than when determined based on distance and the duration of activation of the radiation-emitting device alone.

Detecting the orientation of the apparatus may further advantageously enable feedback to be provided to the user when the apparatus is moved outside of a range of orientations such that delivery of an effective radiation dose cannot been completed.

The processor may be further configured to determine the time duration for which radiation emitted by the radiation-emitting device is incident on the target using the speed and/or acceleration of the apparatus.

The time duration of exposure of the target to radiation may depend, for example, on the speed at which the apparatus is moved across a target area. For example, if the apparatus is directed towards a surface for sterilisation and then moved laterally across the surface, the radiation dose received at a particular point on the surface will depend on the amount of time that the point was within the light cone of the radiation emission. Detecting the speed and/or acceleration of the apparatus advantageously provides further input data to enable the processor to determine the radiant exposure at the target to a higher accuracy than when determined based on distance and the duration of activation of the radiation-emitting device alone.

Detecting the speed and/or orientation of the apparatus may further advantageously enable feedback to be provided to the user when the apparatus is moved outside of a range of speeds and/or accelerations such that delivery of an effective radiation dose cannot been completed.

Determining the radiant exposure further using the orientation, speed, and/or acceleration of the apparatus further enables feedback to be provided to the user to inform the user to adjust the orientation, speed, and/or acceleration of the apparatus in order to achieve the desired radiation dose at the target.

Detecting the orientation, speed, and/or acceleration of the apparatus may also advantageously enable feeding back to the user if the apparatus is not being used safely. For example, an audio and/or visual warning signal may be provided if the apparatus is orientated such that the radiation is emitted in an upward direction, which may present a risk of damage to the user's eyes. A warning signal may also be emitted if the apparatus is moved excessively quickly, which may indicate that the apparatus is not being used safely.

The processor may be further configured to deactivate, and/or prevent activation of, the radiation-emitting device when the apparatus is orientated outside of a pre-determined safe range of orientations. For example, the processor may be configured to deactivate, and/or prevent activation of, the radiation-emitting device when the apparatus is orientated such that the radiation is emitted in an upward direction.

Preventing radiation emission in a particular range of directions advantageously reduces the likelihood of accidental exposure of the user's eyes and/or skin to harmful radiation.

The processor may be further configured to deactivate, and/or prevent activation of, the radiation-emitting device when the movement sensor detects a speed and/or an acceleration of the apparatus that is outside a pre-determined safe range of speeds and/or accelerations.

Preventing radiation emission when the apparatus is moved at an excessive speed or acceleration may advantageously prevent harm to a user or others caused by misuse of the apparatus.

A pre-determined safe range of orientations, accelerations, and/or speeds may be defined by a manufacturer of the apparatus.

The ranging device may comprise a time-of-flight sensor.

The processor may be further configured to receive a required radiant exposure for the target, and calculate a difference between the required radiant exposure for the target and the determined radiant exposure at the target.

The required radiant exposure for the target may be selected from a look-up table.

The processor may receive the required radiant exposure for the target following a manual input of the target dose by the user. Alternatively, or in addition, the processor may receive the required radiant exposure following a user input comprising the target to be irradiated. For example, the user may select a type of organism, or a curable material, from a list. The required dose for that type of organism, or that curable material, may then be determined from a look-up table. The user input may be provided through an interface on the apparatus. Alternatively, or in addition, the user input may be provided through an external communications device and then transmitted to the apparatus (e.g. via a wired or wireless interface). In some examples, the look-up table may be retrieved from the internet.

Receiving the required radiant exposure for the target and calculating the difference between the required radiant exposure and the determined radiant exposure advantageously enables feedback to be provided to the user indicating if the target has, or has not, received the required dose.

Where the required radiant exposure for the target is selected from a look-up table, the apparatus may advantageously be used to deliver a required radiation dose to a target with no requirement that the user have knowledge of the properties of different materials or organisms, or their response to radiation. Instead, the apparatus will always deliver the correct dose based on the specified target, improving the reliability of the apparatus.

The apparatus may be configured to provide an audio and/or visual signal based on the calculated difference.

As an example, the apparatus may comprise a plurality of LEDs having different visible light emission wavelengths. While the determined radiant exposure at the target is less than the required radiant exposure, one or more LEDs having a first emission wavelength may be activated. When the determined radiant exposure at the target reaches or exceeds the required radiant exposure, one or more LEDs having a second emission wavelength may be activated.

Providing an audio and/or visual signal based on the calculated difference means that the user is informed precisely when the required radiation dose has been delivered to the target, and may proceed to deactivate the apparatus, or to move on to a different target. Feeding information back to the user in this way advantageously ensures that the correct radiation dose is delivered to the target with minimal power consumption and in minimal time.

The apparatus may be configured to transmit the calculated difference to an external communications device. For example, the calculated difference may be transmitted to the external communications device via a wired or wireless connection.

Further feedback may be provided to the user via a software interface on the external communications device.

The apparatus may be configured to transmit one or more of the determined distance, the determined time duration, and/or the determined radiant exposure to an external communications device.

In some examples, the apparatus may be further configured to transmit the orientation, speed, and/or acceleration of the apparatus to the external communications device.

Transmitting determined data to an external communications device, for example via a wired or wireless connection, may enable more detailed feedback to be provided to the user via a software interface of the external communications device. For example, the various parameters determined by the processor and the sensors of the apparatus may be displayed to the user. Additional calculations may be performed by software on the external communications device using the distance, time duration, radiant exposure, orientation, speed, and/or acceleration as inputs.

The apparatus may further comprise a liquid sensor configured to detect whether the apparatus is submerged in liquid.

In an example, where the apparatus is to be used both in and out of liquid, the required radiation intensity and/or the duration may depend on whether the target is submerged in liquid (e.g. water). The processor may therefore be further configured to adjust a required dose for a given target based on whether or not it is in liquid.

The processor may be further configured to deactivate and/or prevent activation of the radiation-emitting device when liquid sensor detects that the apparatus is not submerged in liquid. Alternatively, the processor may be further configured to deactivate and/or prevent activation of the radiation-emitting device when the liquid sensor detects that the apparatus is submerged in liquid.

In applications where the apparatus is to be submerged in liquid during use, such as when employed to destroy unwanted aquatic organisms, it may be advantageous to prevent activation of the radiation-emitting device when the apparatus is not submerged in liquid, which would indicate that the apparatus is not in a state of use. Such a feature would prevent accidental activation of the radiation-emitting device, for example by a child, and therefore prevent accidental exposure to harmful radiation.

In applications where the apparatus is not to be submerged in liquid, for example where the apparatus is not waterproof, it may be advantageous to prevent activation of the radiation-emitting device if the apparatus is submerged in liquid. For example, this may reduce the risk of electrocution.

The liquid sensor may comprise a plurality of electrodes, and the liquid sensor may be further configured to measure a conductance between the electrodes; and the processor may be further configured to determine whether the conductance between the electrodes is above a threshold value; wherein, before an initial activation of the radiation-emitting device, the threshold value is a first threshold value; and when the processor determines that the conductance is above the first threshold value, the processor may be further configured to adjust the threshold value to a second threshold value; wherein a difference between the conductance and the second threshold value is a predetermined value.

In some applications where the apparatus is to be submerged in liquid during use, the apparatus may be used in several different artificial aquatic environments comprising liquids having different conductivities, e.g. water having different salinities. It is desirable that the radiation-emitting device be prevented from activation when the apparatus is removed from the liquid. However, in examples where the liquid sensor is configured to measure a conductance between electrodes, some residual liquid may remain on the liquid sensor following removal of the apparatus from the liquid. The residual liquid may enable conduction between the electrodes of the sensor to continue even after the apparatus has been removed from the liquid rendering this safety feature ineffectual, in particular where the liquid is highly conductive, e.g. where the liquid has a high salinity. It may therefore be advantageous to adjust the change in conductance required to prevent activation of the radiation-emitting device, corresponding to a removal of the apparatus from liquid, according to the conductivity of the liquid following submersion. That is, such that the difference between the measured conductance in liquid and the threshold value is a predetermined value. The predetermined value may correspond to a minimum change in conductance measured when the apparatus is removed from any liquid.

In an example, the first threshold value may correspond to a conductance measured in freshwater. If the apparatus is submerged in saltwater, the difference between the measured conductance of the saltwater and the second threshold value may correspond to a minimum change in conductance expected to be measured when the apparatus is removed from the saltwater, rather than a return to the conductance measured before the apparatus was submerged in any liquid.

The apparatus may further comprise a motion sensor configured to detect the presence of humans or animals in a path of radiation emitted by the radiation-emitting device, and the processor may be further configured to deactivate and/or prevent activation of the radiation-emitting device when the motion sensor detects the presence of one or more humans or animals in the path of radiation.

In some examples, the motion sensor may comprise a passive infrared (FIR) sensor.

Preventing emission of potentially harmful radiation when a human or animal is in the path of the radiation provides further safety advantages as the risk of exposure of a human or animal to the radiation is minimised.

The apparatus may further comprise a near-field communications (NFC) sensor configured to detect the presence of an NFC tag, and the processor may be further configured to deactivate and/or prevent activation of the radiation-emitting device in the absence of a present NFC tag.

It will be understood that, in the context of the present disclosure, an NFC tag may comprise a radio frequency identification (RFID) tag.

Where an NFC tag is required to activate the radiation-emitting device, a person is prevented from using the apparatus without possessing the NFC tag. This may further advantageously prevent accidental or unauthorised discharge of harmful radiation, for example by a child if the apparatus were left unsupervised. In some examples, the user may be required to provide physical contact between the NFC tag and the apparatus at regular time intervals. In some examples, the user may be required to maintain constant contact between the NFC tag and the NFC sensor.

In an example, the NEC tag may be incorporated into personal protective equipment (PPE) such as safety glasses. In this example, the user must be in possession of the PPE in order to use the apparatus. In a further example, the NFC tag may be incorporated into an item that must remain in constant contact with the apparatus while in use, for example a ring or wristband.

The radiation-emitting device may comprise one or more LEDs.

LEDs are durable, long-lived, and highly energy efficient compared to other light-emitting devices such as fluorescent lamps or incandescent lamps. A radiation-emitting device comprising one or more LEDs therefore advantageously provides a durable and energy efficient apparatus having a long usable lifetime. Where the apparatus comprises an internal power source, the lifetime of the internal power source is advantageously increased by the use of one or more LEDs over other types of light-emitting devices.

The radiation-emitting device may be configured to emit UV-C radiation.

The apparatus may further comprise a sensor configured to detect an intensity of radiation emitted by the radiation-emitting device, and the processor may be further configured to monitor an output power of the radiation-emitting device using the detected intensity of radiation If the output power of the radiation-emitting device changes, for example due to degradation of the radiation-emitting device, or input power fluctuations, the radiant exposure at the target will change. Therefore, monitoring the output power of the radiation-emitting device advantageously enables corrective action to be taken to ensure that the required radiant exposure at the target is maintained.

We also describe a device for sterilising surfaces, the device comprising the apparatus described herein.

In addition, we describe a device for destroying unwanted aquatic organisms, the device comprising the apparatus described herein.

We further describe a device for curing materials by radiation, the device comprising the apparatus described herein.

LIST OF FIGURES

We shall now describe the present invention by way of example only with reference to the accompanying figures, in which Figure 1 shows a prior art example of a fixed lamp for providing a radiation dose to a surface; Figure 2 shows a prior art example of a traditional surface wipe for providing sterilisation of a surface; Figure 3 shows a radiation-emitting device capable of being moved around in free space for providing a radiation dose to a surface; Figure 4 shows schematically an example of a portable apparatus for providing a radiation dose to a target, and an external communications device connected to the apparatus via a data interface; Figure 5 shows a further example of a portable apparatus that can be orientated in free space for providing a radiation dose to a target; Figure 6 shows a further example of a portable apparatus, with personal protective equipment and a safety cap; and Figure 7 shows an example algorithm for providing a series of checks that may be performed by the apparatus to prevent emission of radiation in potentially unsafe conditions.

The features of the drawings are numbered as follows: 1. Target 2. Shadow region 3. Fixed lamp 4. Surface wipe 5. Body 6. Radiation 7. Personal protective equipment 8. Radiation-emitting device 9. Ranging device 10. Target illumination component 12. Cover glass 13. Button 14. Processor 15. Movement sensor 16. User feedback components 17. Power supply 18. Dosage selector 19. Liquid sensor 20. Wireless connection component

21. Near-Field Communications sensor

22. Software 23. Data interface 24. Safety cap 25. Movement orientations 26. External communications device

27. Near-Field Communications tag

28. Motion sensor 100. Apparatus 200. Algorithm 202. Button held on check 204. Battery check 206. NFC check for PPE 208. Battery check 210. Liquid check 212. Range check 214. Movement check 216. Feedback On Working 218. Radiation On 220. Feedback warning 222. Feedback warning 224. Corrective action 226. Radiation off, and feedback warnings

DETAILED DESCRIPTION

The use of radiation (in particular UV-C radiation) in clinical applications is increasing rapidly and its ability to neutralise both viruses and bacteria are well documented. As illustrated in Figure 1, radiation 6 presently tends to be delivered to a target 1 via a fixed lamp 3, which can create shadow region 2 that does not receive a radiation dose.

Furthermore, as illustrated in Figure 2, a traditional surface wipe 4 is unable to reach into deep cracks or shadow regions 2 as the wipe 4 acts as a bridge. As an example, the target 1 may be a keyboard in a hospital being used by numerous employees. A wipe across the top would clean the tops of the buttons, but as the buttons are depressed fingers touch the sides of the buttons. The sides of the buttons would form the shadow regions 2 illustrated in Figures 1 and 2, and these regions would not be sterilised by either of the methods described above.

The present invention addresses the above deficiencies by providing a radiation source On the form of a radiation-emitting device 8) that can be moved around in free space to deliver radiation 6 to a target 1, as shown schematically in Figure 3. Because the radiation-emitting device 8 is not fixed, the surface of the target 1 can be irradiated in its entirety, leaving no shadow areas.

The present invention has applications in, for example, destruction of unwanted organisms such as viruses and/or bacteria for sterilisation purposes, as well as unwanted bacteria, algae, stinging anemones or other organisms in aquatic environments, and in curing or materials by radiation. A minimum radiation dose, i.e. radiant exposure (fluence) is required to ensure total biological destruction of a target organism (or sufficient curing of a target material).

The importance of dosage (fluence) on the influence of the inactivation of photoreactivation is described below in relation to UV-C radiation. In essence, this is the amount of UV-C radiation required to achieve a sufficient dosage to ensure that the target organism cannot recover from the radiation and is thus all biological activity is destroyed. In insufficiently damaged organisms and cells, photorecovery can occur in certain species. A special enzyme called photolyase, which is itself activated by visible light, can repair DNA sufficiently to allow the organism to recover. Humans no longer possess photolayse enzymes but many bacteria, fungi, plants and some animals do.

The difference in effective dose rate between species varies hugely, mostly depending on the complexity and size of the organism. The most easily treated are phototropic microorganisms, such as those found living in water. These are controlled by relatively low levels of UV-C. For example, some species of bacteria are the most easily inactivated whilst algae, cysts, moulds, and viruses can require a higher dose rate and so on with multicellular organisms and animals requiring the most. Protozoans, often referred to as single-celled animals, can require up to 100 times dose of some simple bacteria yet are still single-celled.

The UV-C light range is from 100-280nm. Without wishing to be bound by theory, the key peak wavelength for maximum inactivation (sterilisation) is widely deemed to be 253.7 nm, or around 254 nm.

Radiant exposure is the radiant energy received by a surface per unit area, and is typically measured in mJ/cm2, or equivalently pVV*s/cm2.

One challenge is to deliver a known radiant exposure to the organism to ensure that the target is sufficiently irradiated to achieve the desired outcome, e.g. sterilisation. Furthermore, the dose may change if delivered in water.

The term D90 is the dose value as a measure for the UVC tolerance and specifies the dose level at which 90% of a specific type of microorganism is inactivated. The UVC interaction is considered a stochastic effect in which a subsequent 090 dose exposure will subsequently affect 90% of the remainder of the microorganism.

Studies have found a range of D90 values for coronaviruses of 7-2410 J/m2 and the average of all studies is 237 J/m2. Excluding outliers, the mean D90 is 47 J/m2, and this should adequately represent the ultraviolet susceptibility of the SARS-CoV-2 (COVID19) virus. However, recent studies have found an average value of the D90 of 27 J/m2, which suggests the average value for all coronaviruses reported above (47 J/m2) is conservative.

The radiation dose required for a given purpose will depend on the target (e.g. organism or material), and can vary between different target organisms or materials (for example between viruses and pest anemones) by orders of magnitude, so being able to adjust/control dose is very important. However, because the relationship between the intensity of radiation received at a target and the distance between the radiation source and the target follows an inverse square law, small changes in the distance between the radiation source and the target (for example caused by small amounts of movement of a handheld source) make a large difference to the radiant exposure at the target. The present invention therefore further provides an apparatus that is capable of monitoring the radiant exposure at a target as it varies with distance to the target, and exposure time, in real-time.

An example of a portable apparatus 100 for providing a radiation dose to a target is illustrated schematically in Figure 4. The apparatus 100 comprises a radiation-emitting device 8, such as a UV-C LED, fitted in a body 5. The body 5 may be, for example, a handheld torch assembly. The body 5 may comprise plastic and/or metal. In some examples, the portable apparatus 100 (comprising the radiation-emitting device 8 and the body 5) may be environmentally protected for use in harsh environments or underwater.

The apparatus 100 may comprise a power supply 17, such as a battery or a mains electricity supply, and a button 13, such as an on/off switch, a momentary, or equivalent to enable a user to turn the radiation beam on and off. The apparatus 100 comprises a ranging device 9, such as a time-of-flight sensor, configured to operate on the same axis as the radiation-emitting device 8. The ranging device 9 is configured to determine ranging data relating to a distance between the apparatus 100 and the target 1. As illustrated in Figure 5, the apparatus 100 is capable of movement in any orientation 25 in free space. Returning to Figure 4, the apparatus 100 may further comprise a movement sensor 15, such as a M EMS sensor, which may be configured to detect gyroscopic and/or accelerative movement, and/or to detect an orientation of the apparatus 100 in free space, i.e. in the X, Y, and Z directions, illustrated in Figure 5.

The apparatus 100 further comprises a processor 14, configured to determine a distance between the apparatus 100 and the target 1 based on range data obtained by the ranging device 9, and further to determine the radiant exposure at the target 1 using the determined distance and a duration of time for which the radiation-emitting device 8 is active. In some examples, the processor 14 may be further configured to determine the time duration over which the target 1 is exposed to radiation 6 using speed, acceleration and/or orientation data obtained by the movement sensor 15. The processor 14 may further be configured to determine the radiant exposure using calibrated power and/or emission wavelength data for the radiation-emitting device 8. This data may be provided in an internal calibration file provided by the manufacturer at the time of production.

In some examples, the apparatus may further comprise a sensor configured to detect an intensity of radiation 6 emitted by the radiation-emitting device 8, and the processor 14 may be further configured to monitor an output power of the radiation-emitting device 8 using the detected intensity. The processor 14 may then be further configured to determine the radiant exposure at the target 1 using the output power monitored in real time.

The ranging device 9 and/or movement sensor 15 may also may also enable a digital interlock preventing discharge of potentially harmful radiation if the apparatus 100 is being used incorrectly, such as if a child were to pick it up and wave it around. Specifically, the processor 14 may be configured to deactivate and/or prevent activation of the radiation-emitting device 8 if the apparatus 100 is moved and/or orientated outside of a safe range.

Returning to Figure 4, the apparatus 100 may further comprise user feedback components 16, which may comprise, for example, an arrangement of lights or a screen providing real-time feedback relating to the applied radiation dose. The user feedback components 16 may be fixed to the body 5 of the apparatus 100. As an example, the user feedback could take the form of a change in colour or a flashing sequence of a light or series of lights, and/or an audible signal. The user feedback may indicate, for example, whether the apparatus 100 is sufficiently close to the target to provide effective irradiation. If the user feedback indicates that the apparatus 100 is too far away, the user will be informed that they must move the apparatus 100 closer to the target.

Alternatively, or in addition, the apparatus 100 may comprise a target illumination component 10, such as a visible light-emitting device, which may be arranged to illuminate the target with visible light approximating the illumination of the target with radiation from the radiation-emitting device 8, where the radiation from the radiation-emitting device 8 may be invisible. The target illumination component 10 may assist the user in aiming the radiation-emitting device 8 at the target. Furthermore, the target illumination component 10 may be configured to provide feedback to the user as described above in relation to the user feedback components 16, for example by providing a change in illumination colour or flashing sequence.

In some examples the apparatus 100 may be configured to transmit data to, and/or receive data from, an external communications device 26 (such as a smartphone or a personal computer) via a wired or wireless data interface 23 such as a data transfer cable, or a Bluetooth (RTM) or Wi-Fi (RTM) connection. As an alternative, or in addition, to the user feedback components 16, user feedback may be provided to the user via software 22 on the external communications device 26. The software 22 may also be capable of controlling the radiation-emitting device 8 (e.g. switching it on/off, controlling an output power etc.), as well as providing detailed outputs comprising the data obtained by the various sensors 9, 15 of the apparatus 100. Where the apparatus is configured to transmit and/or receive data via a wireless connection, the apparatus 100 may further comprise a wireless connection component 20.

As discussed above, the apparatus 100 may potentially be employed in a wide range of applications with the target comprising any number of many different types of organisms and/or materials, and new experimental data is regularly made available in relation to the effects of germicidal radiation on different organisms. The processor 14 may therefore be further configured to receive a required radiant exposure for a given target. The required radiant exposure may be inputted by the user via an interface directly on the device, such as a dosage selector button 18. It may not be realistic to assume that the user will be familiar with the required radiation doses of every possible target organism or material. The required radiant exposure may therefore be obtained from a look-up table following a selection of the target organism or material by the user. Where the apparatus 100 is configured to receive data from an external communications device 26, the user may input a required radiant exposure, and/or select the target organism or material, via software 22 on the external communications device 26. The processor 14 may be configured to calculate a difference between the required radiation dose (i.e. radiant exposure) and the determined radiant exposure at the target. The apparatus 100 may then provide feedback to the user, for example via the user feedback components 16, the target illumination component 10, and/or the software 22 on the external communications device 26, indicating whether the required radiation dose has been delivered.

In some examples, the apparatus 100 comprises a liquid sensor 19, for example to detect whether the apparatus 100 is submerged in water. In some examples, the liquid sensor 19 may comprise a conductive sensor, a capacitive sensor, an optical sensor, and/or any other sensor suitable for detecting liquid. The intensity and/or duration of applied radiation may change when the transmission medium changes from air to liquid (e.g. water). The processor 14 may therefore be further configured to determine a new required radiation dose for the organism following detection by the liquid sensor 19 that the apparatus 100 has been submerged.

If the apparatus 100 is to be used exclusively for underwater applications, the liquid sensor 19 may further provide an additional interlock function for preventing accidental discharge of radiation improving battery/component lifetimes and safety. Conversely, the liquid sensor 19 may operate as an interlock if the apparatus 100 is to be used exclusively in air.

Where the apparatus 100 is to be used exclusively in liquid, the liquid sensor 19 may comprise a conductive sensor for which the principle of operation is that the in water/out water state is determined by measuring a conductance between a plurality of electrodes. The conductivity of water is highly dependent upon the quantity of mineral salts dissolved in solution, salt water providing an order of magnitude higher conductivity than fresh water. The apparatus 100 would be intended for use in fresh water and salt water aquatic environments and any safety interlocks should always function correctly in either environment. The inventors found during testing that, when an initial threshold (a first threshold) for measured conductivity is set for the interlock to allow operation in fresh water, when the electrodes were removed from the water the out of water reading did not always return to the pre-submersion reading. This was found to be due, at least in part, to residual contamination between the electrodes causing a residual level of conduction between the electrodes. To ensure that the interlock is reliable the fail threshold (i.e. the threshold for conduction below which the radiation-emitting device 8 is deactivated or prevented from activation) is modified based on the measured conductance. That is, the modified threshold (second threshold) requires a relatively small decrease in the conductance and not a return to the pre-immersion value. It will be understood that the threshold would return to the stricter threshold (first threshold) when the apparatus 100 is turned off. It may be necessary for a user to rinse or otherwise clean the apparatus 100 of any residual saltwater between uses so that the interlock remains effective.

Where the apparatus 100 is to be used in liquid, the body 5 is typically environmentally protected and a cover glass 12 or lens is typically present over the radiation-emitting device 8, wherein the cover glass 12 or lens is watertight and transparent to the radiation emitted by the radiation-emitting device 8.

Figure 6 illustrates an example of personal protective equipment (PPE) 7 that may be employed by the user when using the apparatus 100. For example, the PPE 7 may comprise safety glasses configured to protect the user's from accidental exposure to radiation emitted by the radiation-emitting device 8. In some examples, the apparatus 100 may further comprise a near-field communications (NEC) sensor 21, and the PPE 7 may further comprise an NFC tag 27.

In an example, activation of the radiation-emitting device 8 may require the user to make contact between the NFC tag 27 and the NFC sensor 21. Activation of the radiation-emitting device 8 may be time-limited, such that the user must make contact between the NFC tag 27 and the NFC sensor 21 regularly at a pre-set time interval. In such an example, it would not be possible to use the apparatus 100 without possession of the PPE 7, reducing the likelihood of accidental exposure to harmful radiation.

Alternatively, or in addition, the NFC tag 27 may be attached to a non-PPE item, such as a key fob or identity card. In this example, the apparatus 100 cannot be used if the user is not in possession of the item.

In a further example, the NFC tag 27 may be attached to an item that is intended to be worn on the user's hand while holding the apparatus 100, such as a ring or wristband. In such an example, the NFC tag 27 may be required to maintain continual contact with the NEC sensor 21 to enable activation of the radiation-emitting device 8. If contact between the NEC tag 27 and the NEC sensor 21 is broken, for example if the user drops the apparatus 100, the radiation-emitting device may be deactivated, or prevented from activation.

In some examples, the NFC sensor 21 may be employed for data transfer between the apparatus 100 and an external device. For example, the data interface 23 illustrated in Figure 4 may comprise NFC.

In some examples, a safety cap 24 may be placed over the radiation-emitting device 8 when the apparatus 100 is not in use, further to prevent accidental exposure to radiation.

Returning to Figure 4, the apparatus 100 may further comprise a motion sensor 28 for detecting the presence of humans and/or animals in the radiation path. For example, the motion sensor 28 may be a passive infrared (PI R) sensor. When the motion sensor 28 detects a human or animal in the radiation path, the processor 14 may deactivate and/or prevent activation of the radiation-emitting device 8, further reducing the risk of accidental exposure to radiation.

Figure 7 illustrates an example of an algorithm 200 for providing a series of checks that may be performed by the apparatus 100, for example by the processor 14, to prevent activation of the radiation-emitting device 8 in conditions where its activation may be potentially unsafe. For example, a first check 202 may establish whether an activation button has been deliberately pressed, such as by being held down. Additional checks may include battery checks 204, 208, for example to establish whether the power supply is operating safely and stably, a liquid check 210, and a check for the presence of PPE by NEC 206. Where any check fails, the radiation-emitting device may be prevented from activation ("radiation off" 226) and a series of feedback warnings may be provided to the user. Further checks that the apparatus 100 is being held at a suitable range (range check 212), and being moved within a certain tolerance of speeds/accelerations/orientations (movement check 214), may also be performed.

Where all of the checks are passed, the apparatus 100 may provide further feedback 216 that the radiation-emitting device 8 is on and working, and the radiation-emitting device Swill switch on 218. Where the range check 212 and movement check 214 fail, the user may be provided with a feedback warning 220, 222, such as via the feedback components 16 described above, and given an opportunity to make a corrective action 224. For example, to slow the apparatus 100 down, to reorientate the apparatus 100, and/or to move the apparatus 100 closer to the target 1. If the corrective action 224 is sufficient to pass the range check 212 and the movement check 214, the apparatus 100 may proceed to provide further feedback 216 that the radiation-emitting device 8 is on and working, and the radiation-emitting device Swill switch on 218. One or more of the checks may be repeated (looped), and may be required to be passed continuously to maintain the radiation output.

Although the present invention has been described hereinabove with reference to specific embodiments, the present invention is not limited to the specific embodiments and modifications will be apparent to a skilled person in the art which lie within the scope of the present invention. Any of the embodiments described hereinabove can be used in any combination.

Claims

CLAIMS: 1. A portable apparatus for providing a radiation dose to a target, the apparatus comprising: a radiation-emitting device; a ranging device; and a processor configured to determine a distance between the apparatus and the target based on range data obtained by the ranging device, and to determine a time duration for which radiation emitted by the radiation-emitting device is incident on the target; wherein the processor is further configured to determine a radiant exposure at the target using the determined distance between the apparatus and the target and the determined time duration.
2. The apparatus of claim 1, further comprising a movement sensor configured to detect at least one of an orientation, a speed, and/or an acceleration of the apparatus.
3. The apparatus of claim 2, wherein the movement sensor comprises a MEMS sensor.
4. The apparatus of claim 2 or 3, wherein the processor is further configured to determine the time duration for which radiation emitted by the radiation-emitting device is incident on the target using the orientation of the apparatus.
5. The apparatus of any one of claims 2 to 4, wherein the processor is further configured to determine the time duration for which radiation emitted by the radiation-emitting device is incident on the target using the speed and/or acceleration of the apparatus.
6. The apparatus of any one of claims 2 to 5, wherein the processor is further configured to deactivate, and/or prevent activation of, the radiation-emitting device when the apparatus is orientated outside of a pre-determined safe range of orientations.
7. The apparatus of any one of claims 2 to 6, wherein the processor is further configured to deactivate, and/or prevent activation of, the radiation-emitting device when the movement sensor detects a speed and/or an acceleration of the apparatus that is outside a pre-determined safe range of speeds and/or accelerations.
8. The apparatus of any one of the preceding claims, wherein the ranging device comprises a time-of-flight sensor.
9. The apparatus of any one of the preceding claims, wherein the processor is further configured to: receive a required radiant exposure for the target; and calculate a difference between the required radiant exposure for the target and the determined radiant exposure at the target.
10. The apparatus of any one of the preceding claims, wherein the required radiant exposure for the target is selected from a look-up table.
11. The apparatus of claim 9 or 10, configured to provide an audio and/or visual signal based on the calculated difference between the required radiant exposure for the target and the determined radiant exposure at the target
12. The apparatus of any one of claims 9 to 12, configured to transmit the calculated difference between the required radiant exposure for the target and the determined radiant exposure at the target to an external communications device.
13. The apparatus of any one of the preceding claims, configured to transmit one or more of the determined distance, the determined time duration, and/or the determined radiant exposure to an external communications device.
14. The apparatus of any one of the preceding claims, further comprising a liquid sensor configured to detect whether the apparatus is submerged in liquid.
15. The apparatus of claim 14, wherein the processor is further configured to deactivate and/or prevent activation of the radiation-emitting device when the liquid sensor detects that the apparatus is not submerged in liquid.
16. The apparatus of claim 14, wherein the processor is further configured to deactivate and/or prevent activation of the radiation-emitting device when the liquid sensor detects that the apparatus is submerged in liquid.
17. The apparatus of claim 14 or 15, wherein the liquid sensor comprises a plurality of electrodes, and further wherein the liquid sensor is configured to measure a conductance between the electrodes; wherein the processor is further configured to determine whether the conductance between the electrodes is above a threshold value; wherein, before an initial activation of the radiation-emitting device, the threshold value is a first threshold value; and wherein, when the processor determines that the conductance is above the first threshold value, the processor is further configured to adjust the threshold value to a second threshold value; wherein a difference between the conductance and the second threshold value is a predetermined value.
18. The apparatus of any one of the preceding claims, further comprising a motion sensor configured to detect the presence of humans or animals in a path of radiation emitted by the radiation-emitting device; wherein the processor is further configured to deactivate and/or prevent activation of the radiation-emitting device when the motion sensor detects the presence of one or more humans or animals in the path of radiation.
19. The apparatus of any one of the preceding claims, further comprising a near-field communications sensor;wherein the near-field contact sensor is configured to detect the presence of a near-field communications tag; and wherein the processor is further configured to deactivate and/or prevent activation of the radiation-emitting device in the absence of a present near-field communications tag.
20. The apparatus of any one of the preceding claims, wherein the radiation-emitting device comprises one or more light-emitting diodes.
21. The apparatus of any one of the preceding claims, wherein the radiation-emitting device is configured to emit UV-C radiation.
22. The apparatus of any one of the preceding claims, further comprising a sensor configured to detect an intensity of radiation emitted by the radiation-emitting device, and wherein processor is further configured to monitor an output power of the radiation-emitting device using the detected intensity of radiation.
23. A device for sterilising surfaces, the device comprising the apparatus of any one of the preceding claims.
24. A device for destroying unwanted aquatic organisms, the device comprising the apparatus of any one of claims 1 to 22.
25. A device for curing materials by radiation, the device comprising the apparatus of any one of claims 1 to 22.