WO2021254619A1

WO2021254619A1 - Self-sanitizing electronic device

Info

Publication number: WO2021254619A1
Application number: PCT/EP2020/066914
Authority: WO
Inventors: Torsten Wipiejewski; Markku Rouvala; Mikko Terho
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2020-06-18
Filing date: 2020-06-18
Publication date: 2021-12-23
Also published as: CN115768488A

Abstract

A self-sanitizing electronic device (1), such as comprising a waveguide structure (3) and a radiation source (4) configured to emit electromagnetic radiation (R) within an ultraviolet spectrum into the waveguide structure (3). The waveguide structure (3) is superimposed onto a device surface (2a) and comprises a waveguide layer (5) having a first interface surface (5a) facing surrounding air and a second interface surface (5b) facing the device surface (2a). The waveguide layer (5) is configured to allow the electromagnetic radiation (R) to propagate within the waveguide layer (5) and an evanescent field (F) generated by the electromagnetic radiation (R) to penetrate the first interface surface (5a) and travel into the air as it propagates within the waveguide layer (5). The evanescent field (F) sanitizes the first interface surface (5a) by destroying e.g. virus and bacteria. The electronic device is sanitized continuously, and not at all dependent on manual labor or other, external devices.

Description

SELF-SANITIZING ELECTRONIC DEVICE

TECHNICAL FIELD

The disclosure relates to an electronic device comprising an outer device surface, the device surface being sanitized using radiation.

BACKGROUND

Surfaces which are contaminated with viruses or bacteria, and which are touched by humans, can transmit the virus or bacteria via so-called indirect contact infection. Fixed and more or less public electronic devices such as elevator buttons or keypads are very much at risk of such contamination, but also more or less individual, portable electronic devices such as smart phones and tablets are significant contamination hazards.

Electronic devices are currently disinfected either by hand, by applying liquid disinfectant manually, or semi-automatically by placing them within some kind of sanitizing device. Manual sanitizing is time-consuming and inefficient, and can lead to end results of varying quality. Semi-automatic sanitizing using a device still requires manual labor to some degree, and may even be impossible due to the size and/or location of the device in need of sanitizing. Additionally, when sanitizing is executed using radiation, e.g. UV (ultraviolet) light, health considerations require the sanitizing to take place within a completely sealed off environment such as a casing due to concerns relating to dosage and time of exposure to the radiation.

Furthermore, neither of these sanitizing processes are executed continuously, nor is it practicable to sanitize between every instance of use. SUMMARY

It is an object to provide an electronic device with improved hygiene features. The foregoing and other objects are achieved by the features of the independent claim(s). Further implementation forms are apparent from the dependent claims, the description, and the figures.

According to a first aspect, there is provided a self- sanitizing electronic device comprising a surface element comprising a device surface, such as an outer display or back cover surface. The electronic device further comprises a waveguide structure superimposed onto the device surface such that a main plane of the device surface and a main plane of the waveguide structure extend in parallel, and a radiation source configured to emit electromagnetic radiation within an ultraviolet spectrum into the waveguide structure. The waveguide structure comprises a waveguide layer having a first interface surface facing surrounding air and a second interface surface facing the device surface. The waveguide layer is configured to allow the electromagnetic radiation to propagate within the waveguide layer in a first direction parallel with the main planes so as to allow an evanescent field generated by the electromagnetic radiation to penetrate the first interface surface into the air, the evanescent field sanitizing the first interface surface. The evanescent field penetrates the first interface surface in a second direction perpendicular to the first direction and away from the device surface.

This solution allows ultraviolet radiation to travel across the entire area of the waveguide structure, subsequently allowing ultraviolet radiation to be distributed across the entire outer surface of the electronic device. The waveguide structure confines the ultraviolet radiation substantially inside the electronic device, with exception of a very small distance just outside the waveguide layer. The electronic device is sanitized continuously, and not at all dependent on manual labor or other, external devices. Furthermore, since the waveguide structure is arranged at the exterior of the electronic device it has very little impact on the arrangement of the other components of the electronic device. In a possible implementation form of the first aspect, the waveguide structure comprises a plurality of layers, wherein main planes of the layers extend in parallel with each other and with the main plane of the waveguide structure. By allowing the waveguide structure and its layers to extend such that the radiation path is parallel with the main device surface, the waveguide structure can have a very low height which does not affect the total thickness of the device noticeably.

In a further possible implementation form of the first aspect, the waveguide structure further comprises an adhesion layer configured to adhere the waveguide structure to the device surface, facilitating simple, reliable and even attachment of the waveguide structure to the device surface.

In a further possible implementation form of the first aspect, the waveguide layer comprises a radiation input end, and the electromagnetic radiation enters the waveguide layer at the radiation input end.

In a further possible implementation form of the first aspect, the wavelength of the electromagnetic radiation is preferably between 100 and 400 nm, more preferably between 190 and 280 nm, there wavelengths being most efficient in destroying virus or bacteria.

In a further possible implementation form of the first aspect, the average penetration depth of the evanescent field into the surrounding air, from the first interface surface, corresponds to the wavelength within a range of 0.5 x wavelength to 2 x wavelength. The distance of a few hundred nanometers into the ambient air is large enough to destroy any viruses or bacteria, without affecting the health of the user.

In a further possible implementation form of the first aspect, the radiation source is one of an ultraviolet light emitting diode, preferably a low voltage ultraviolet light emitting diode, a high intensity ultraviolet lamp, a super luminescent light emitting diode, and a laser diode. In a further possible implementation form of the first aspect, the waveguide structure further comprises a waveguide cladding layer arranged between the second interface surface of the waveguide layer and one of the device surface and the adhesion layer, the waveguide cladding layer being configured to minimize absorption loss at the second interface surface.

In a further possible implementation form of the first aspect, the waveguide cladding layer comprises a material having a lower refractive index than the material of the waveguide layer. The difference in refractive index facilitates efficient transmission of radiation.

In a further possible implementation form of the first aspect, the waveguide cladding layer comprises a film or atomic layer deposit, allowing an as thin, yet still effective, layer as possible.

In a further possible implementation form of the first aspect, the waveguide cladding layer has a refractive index of 1.3-1.5, and the waveguide layer has a refractive index of 1.5-2.5.

In a further possible implementation form of the first aspect, the waveguide cladding layer comprises at least one of CaF and MgF.

In a further possible implementation form of the first aspect, the waveguide layer comprises at least one of fused silica, spinel, sapphire, and CaC03. Such hard ceramic materials have high resistance against mechanical damage and wear, and allows long lasting, effective sanitizing. Furthermore, the sanitizing process can easily be monitored and controlled by electronics.

In a further possible implementation form of the first aspect, the waveguide layer comprises materials allowing it to have a radiation loss of less than 10 dB/cm, preferably less than 1 dB/cm. In a further possible implementation form of the first aspect, the waveguide structure further comprises an electromagnetic radiation sensing arrangement at least partially arranged between the second interface surface of the waveguide layer and one of the device surface and the adhesion layer, preferably between the waveguide cladding layer and the device surface or the adhesion layer. The sensing arrangement is configured to detect electromagnetic radiation within the ultraviolet spectrum and generate an indication that the electromagnetic radiation has been detected, allowing any unwanted leakage of ultraviolet radiation to be detected.

In a further possible implementation form of the first aspect, the sensing arrangement comprises a sensing layer and a photodetector, the sensing layer being configured to generate electromagnetic radiation within the visible or near infrared spectrum, and transmit the visible or near infrared spectrum radiation to the photodetector. This allows monitoring to be automatic and continuous, and the detection of leakages to go either unnoticed or noticed, as desired.

In a further possible implementation form of the first aspect, the self-sanitizing electronic device further comprises a control and monitoring system operatively connected to the waveguide structure and configured to control and/or monitor electromagnetic radiation emitted by the radiation source, allowing the sanitizing process to be completely automatic and performed in continuous mode.

In a further possible implementation form of the first aspect, the surface element comprises a user touch function, and the control and monitoring system is configured to deactivate the radiation source in response to activation of the user touch function by a user, and/or in response to the photodetector detecting visible or near infrared spectrum radiation. This facilitates avoiding human skin to be in direct contact with ultraviolet radiation, since the radiation source can be switched off when the device is used and/or device surface touched.

In a further possible implementation form of the first aspect, the control and monitoring system is configured to modulate and/or filter signals generated by electromagnetic radiation detected by the sensing arrangement, such that signals corresponding to ambient electromagnetic radiation can be distinguished from signals corresponding to electromagnetic radiation emitted by the radiation source, such that the sensing arrangement does not register, e.g., radiation emitted by the sun.

In a further possible implementation form of the first aspect, the waveguide structure further comprises an incoupling arrangement, the incoupling arrangement being configured to direct electromagnetic radiation emitted by the radiation source into the waveguide layer. This allows the radiation source to be placed in a position optimal for electronic functionality and in view of mechanical constraints, independently from the position of the waveguide layer. Furthermore, by folding the radiation path, the waveguide structure can be made to have a very small height and/or other components may be maneuvered around.

In a further possible implementation form of the first aspect, the incoupling arrangement comprises at least one of a reflective surface, a grating coupler structure, or a prism structure. By such a solution, the position of the radiation source can be decoupled from the position of the waveguide layer. This not only allows the radiation source to be placed optimally in view of electronic functionality and mechanical constraints, but also the size of the radiation source will no longer be a significant limiting factor, since it may be placed wherever suitable within the electronic device.

In a further possible implementation form of the first aspect, the radiation source and/or the incoupling arrangement is arranged adjacent a peripheral edge of the electronic device.

In a further possible implementation form of the first aspect, the surface element is one of a display assembly and a back cover. This allows sanitizing of a part of, or the entire, outer surface of the electronic device, provides an electronic device with an integral appearance, and provides additional protection for the other components of the electronic device.

In a further possible implementation form of the first aspect, the surface element comprises a glass substrate. In a further possible implementation form of the first aspect, the main plane of the device surface and the main plane of the waveguide structure are identically curved adjacent at least one peripheral edge of the electronic device, allowing the entire surface of the electronic device to be sanitized, regardless of its three-dimensional shape.

In a further possible implementation form of the first aspect, the electronic device is one of a smartphone, tablet, wearable key pad, button, or door handle.

These and other aspects will be apparent from the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, the aspects, embodiments and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Figs la and lb show perspective front and rear views of an electronic device in accordance with embodiments of the present invention;

Fig. lc shows a schematic top view of an electronic device in accordance with an embodiment of the present invention;

Fig. 2a shows a schematic top view of an electronic device in accordance with an embodiment of the present invention;

Fig. 2b shows partial cross-sectional views of the embodiment shown in Fig. 2a;

Figs. 3 to 8 show partial cross-sectional views of electronic devices in accordance with different embodiments of the present invention. DETAILED DESCRIPTION

Figs la and lb as well as Figs. 2a and 2b show embodiments of a self-sanitizing, wherein a portable electronic device 1, i.e. a smart-phone, a table, a desktop computer or any portable computer shown in front and rear perspective views. Although Figs la and lb show a smart phone, the present invention can be implemented in any portable electronic device such as a tablet, a notebook or any portable computer. Fig. lc shows one embodiment of a self-sanitizing, fixed electronic device 1 in the form of a button, such as an elevator button. Other embodiments of electronic devices 1 may comprise a tablet, a wearable, a key pad, or a door handle (not shown). Further embodiments of electronic devices 1 are also conceivable and not to be excluded.

The electronic device 1 comprises a waveguide structure 3 arranged on a surface element

2 having an externally directed device surface 2a. The front view of Fig. la shows the waveguide structure 3 arranged on a front surface 2a of the device, such as an outermost surface of a display assembly 2, and the rear view of Fig. 1 b shows the waveguide structure

3 arranged on a rear surface 2a of the device, such as an outermost surface of a back cover 2

The surface element 2 may be a display arrangement comprising a plurality of layers including a transparent outer cover layer, or it may be a cover element such as a housing covering the sides and/or rear of the device. The surface element 2 may comprise a substrate made of glass, plastic, or metal. The substrate is preferably transparent when the surface element 2 is placed at a front surface of the device 1, and is preferably metal only when the surface element 2 is placed at a rear surface of the device 1.

The waveguide structure 3 is superimposed onto the device surface 2a, preferably directly onto the device surface 2a however other elements may be arranged therebetween.

As visualized in Fig. 3, the waveguide structure 3 is superimposed onto the device surface 2a such that a main plane PI of the device surface 2a and a main plane P2 of the waveguide structure 3 extend in parallel, also if and where the device surface 2a is curved, as shown in Fig. 5, or otherwise non-planar, e.g. when the device surface 2a is 2.5 -dimensional or 3- dimensional. 17. The main plane PI of the device surface 2a and the main plane P2 of the waveguide structure 3 may be identically curved adjacent at least one peripheral edge 12 of the electronic device 1. In other words, the waveguide structure 3 may have the same properties across the entire device surface 2a, regardless of the topology of the device surface 2a.

A radiation source 4 is configured to emit electromagnetic radiation R within an ultraviolet spectrum into the waveguide structure 3. The wavelength L of the electromagnetic radiation R is preferably between 100 and 400 nm, more preferably between 190 and 280 nm.

The radiation source 4 may be one of an ultraviolet light emitting diode, preferably a low voltage ultraviolet light emitting diode, a high intensity ultraviolet lamp, a super luminescent light emitting diode, and a laser diode.

The waveguide structure 3 comprises at least a waveguide layer 5. The waveguide layer 5 has a first interface surface 5a facing the surrounding air, i.e. the exterior of the electronic device 1, and a second interface surface 5b facing the device surface 2a, i.e. the outermost surface of the display assembly or the back cover. The waveguide layer 5 extends in parallel with the device surface 2a, and may be arranged in abutment with the device surface 2a, i.e. directly on top of the device surface 2a, or may be arranged with one or several additional layers therebetween, examples of which will be described in more detail below. The surface element 2 provides support for the waveguide layer 5 such that it may be thin yet still mechanically stable.

The waveguide layer 5 comprises a radiation input end, and the electromagnetic radiation R enters the waveguide layer 5 at the radiation input end. The radiation input end is arranged at the leftest side of the waveguide layer 5 shown in Figs. 3 to 8. The radiation input end may comprise further components, however, the radiation input end 5 may also comprise merely an open and radiation transparent facet cut through the waveguide layer 5, also known as butt-coupling.

The waveguide layer 5 is configured to allow the electromagnetic radiation R to propagate within the waveguide layer 5 in a first direction D1 parallel with the main planes PI, P2. The electromagnetic radiation R, entering the waveguide layer 5 at the radiation input end, subsequently propagates by reflecting within the waveguide layer 5, and finally diminishes due to absorption losses in the material of the waveguide layer 5 and impurities in its surfaces.

This propagation allows an evanescent field F, generated by the electromagnetic radiation R, to evenly penetrate the entire first interface surface 5a and extend somewhat into the surrounding air. The evanescent field F extends, and penetrates the first interface surface 5a, in a second direction D2 perpendicular to the first direction D1 and away from the device surface 2a and surface element 2, as indicated by arrows in Figs. 2b to 8. The evanescent field F sanitizes the first interface surface 5a.

The penetration depth d of the evanescent field F is a function of the refractive index of the waveguide layer 5 and the angle at which each ray of electromagnetic radiation R propagates within the waveguide layer 5. A ray propagating at a very shallow angle, i.e. substantially parallel to the first interface surface 5a, exhibits small penetration into the surrounding medium, whereas a ray propagating at a steep angle shows larger penetration of the evanescent field F into the surrounding medium. Since the total radiation in the waveguide layer 5 is the sum of many rays propagating inside the waveguide layer 5, the penetration depth d of the evanescent field F is also a sum of the contribution from each ray. With a typical homogenous distribution of the radiation rays in the waveguide layer 5, the average sum of the penetration depth d of the evanescent field F is in the order of the wavelength L of the electromagnetic radiation R. For a wavelength L of 200 nm, the average sum penetration depth d would, in this embodiment, be a value within a range of 100 nm to 300 nm. For a wavelength L of 400 nm, the penetration depth d would, in this embodiment, be a value within a range of 200 nm to 600 nm. The evanescent field F always exhibits its maximum at the interface between the waveguide and the surrounding medium. From that point, the field strength decreases with an exponential function in the surrounding medium. The penetration depth d corresponds to the distance to the interface, at which point penetration depth the field strength is reduced to about 30 % of the maximum value.

In one embodiment, the penetration depth d is maximum 1 pm. The maximum intensity of the evanescent field F arises at the first interface surface 5a and the intensity of the evanescent field F is reduced as the evanescent field F penetrates in the second direction D2, i.e. the further away from the first interface surface 5a that the evanescent field F travels. The average intensity of the evanescent field F may be maximum 400 nm, preferably maximum 280 nm.

The waveguide structure 3 may comprises a plurality of layers 5, 6, 7, and the main planes of the layers 5, 6, 7 may extend in parallel with each other and with the main plane P2 of the waveguide structure 3.

In one embodiment, the waveguide structure 3 comprises an adhesion layer 6 configured to adhere the waveguide structure 3 to the device surface 2a. The adhesion layer 6 may comprise of conventional, transparent glue. The waveguide layer 5 may be attached directly to the device surface 2a. The waveguide structure 3 may also be attached to the electronic device 1 by other means, such as being fixed to a peripheral or inner frame or a printed circuit board of the electronic device by means of adhesive or screws.

The waveguide structure 3 may further comprise a waveguide cladding layer 7 arranged between the second interface surface 5b of the waveguide layer 5 and one of the device surface 2a and the adhesion layer 6. The waveguide cladding layer 7 is configured to minimize absorption loss at the second interface surface 5b. Furthermore, the waveguide cladding layer 7 may also protect the adhesion layer 6 such that it is maintained in good condition and remains unaffected by electromagnetic radiation R. The waveguide cladding layer 7 may comprise a material having a lower refractive index than the material of the waveguide layer 5. As an example, the waveguide cladding layer 7 may have a refractive index of 1.3-1.5, and the waveguide layer 5 may have a refractive index of 1.5-2.5.

In one embodiment, the waveguide cladding layer 7 comprises at least one of CaF and MgF. Furthermore, the waveguide cladding layer 7 may be a film or atomic layer deposit. The waveguide layer 5 may comprise at least one of fused silica, spinel, sapphire, and CaC03. Preferably, the waveguide layer 5 comprises materials allowing it to have a radiation loss of less than 10 dB/cm, preferably less than 1 dB/cm.

The waveguide structure 3 may further comprise an electromagnetic radiation sensing arrangement 8, configured to detect electromagnetic radiation R within the ultraviolet spectrum and at least partially arranged between the second interface surface 5b of the waveguide layer 5 and one of the device surface 2a and the adhesion layer 6. Preferably, sensing arrangement 8 is arranged between the waveguide cladding layer 7 and the device surface 2a or the adhesion layer 6, as shown in Fig. 8. As mentioned above, the electromagnetic radiation R propagates within the waveguide layer 5 in the first direction D1 parallel with the main planes PI, P2 and, hence, parallel with the adhesion layer 6 and waveguide cladding layer 7. The electromagnetic radiation R is substantially contained within the waveguide layer 5, i.e. no electromagnetic radiation R penetrates the first interface surface 5 a in the second direction D2. However, if there are defects such as scratches in the waveguide layer 5, changing the optical properties of the layer, electromagnetic radiation R may unwantedly propagate in all directions other than the first direction D1 since the radiation will scatter in a similar way both outwardly, towards the exterior, and inwardly towards the device surface 2a. Hence, electromagnetic radiation R may leak into the surrounding air, and possibly affect the wellbeing or health of the user negatively.

In response to detection of electromagnetic radiation R, the sensing arrangement generates an indication that electromagnetic radiation R has been detected. In one embodiment, the sensing arrangement 8 comprises a sensing layer 8a and a photodetector 8b. The sensing layer 8a is configured to generate electromagnetic radiation R2 within the visible or near infrared spectrum, and transmit the visible or near infrared spectrum radiation R2 to the photodetector 8b. The sensing layer 8a may comprise of plastic film such as polymethyl methacrylate (PMMA) filled with quantum dots, the quantum dot absorption being tailored such that it absorbs ultraviolet radiation and generates visible or near infrared spectrum radiation R2. The visible or near infrared spectrum radiation R2 propagates through the sensing layer 8a to the photodetector 8b which registers the visible or near infrared spectrum radiation R2 and is operably connected to further components configured to alert the user of the device to the fact that there is unintentional leakage of electromagnetic radiation R, or to a control and monitoring system 9 configured to deactivate the radiation source 4. The user of the device may also be alerted directly by the radiation R2 when in the visible spectrum.

The control and monitoring system 9 may be operatively connected to the waveguide structure 3 and configured to control and/or monitor electromagnetic radiation R emitted by the radiation source 4. The control and monitoring system 9 may control the amount of electromagnetic radiation R emitted by the radiation source 4, monitor possible leakage of electromagnetic radiation R using the sensing arrangement 8, alert the user of such a leakage, and/or allow the user of the electronic device 1 to activate or deactivate the radiation source 4.

The surface element 2 may comprise a user touch function 10, the control and monitoring system 9 being operably connected to the touch function 10 and configured to deactivate the radiation source 4 in response to activation of the user touch function by a user, such that the radiation source 4 emits electromagnetic radiation R only when the electronic device 1 is not in use or handled by a user. The radiation source 4 may also be deactivated in response to the photodetector 8b detecting visible or near infrared spectrum radiation R2. The control and monitoring system 9 may further be configured to modulate and/or fdter signals generated by any electromagnetic radiation detected by the sensing arrangement 8, such that signals corresponding to ambient electromagnetic radiation R3, for example ultraviolet radiation emitted by the sun, can be distinguished from signals corresponding to electromagnetic radiation R emitted by the radiation source 4.

Electromagnetic radiation R emitted by the radiation source 4 may be directed straight into the waveguide layer 5. However, the waveguide structure 3 may also comprise an incoupling arrangement 11, indicated in Figs. 2b, 6, and 7. The incoupling arrangement 11 is configured to direct electromagnetic radiation R emitted by the radiation source 4 into the waveguide layer 5. The incoupling arrangement 11 is preferably placed adjacent, and is to some extent aligned with, the radiation source 4 as well as the radiation input end of the waveguide structure 3. A mechanical fixture may be used to place and maintain radiation source 4 and/or the incoupling arrangement 11 in the correct position relative the waveguide layer 5.

The incoupling arrangement 11 may comprise at least one of a reflective surface, as shown in Fig. 7, a grating coupler structure, as shown in Fig. 6, or a prism structure (not shown).

The reflective surface, or a redirecting surface of the grating coupler or prism structure, may be arranged such that the main direction of the electromagnetic radiation R, emitted by the radiation source 4, is redirected to propagate mainly in parallel with the main plane P2 of the waveguide structure 3. Thus, the light propagation within the waveguide structure 3 occurs within an angle distribution to the interface between the waveguide structure 3 and the surrounding waveguide cladding layers 7 that is smaller than the critical angle of total internal reflection. The critical angle of total internal reflection is defined by the refractive indices of the waveguide structure 3 and the cladding layers 7.

The reflective surface or the redirecting surface may extend at an angle a of 35-55°, preferably 45°, to the waveguide structure 3, and be configured to redirect the electromagnetic radiation R by an angle b of 70-110°, preferably 90°. The reflective surface or the redirection surface may comprise at least one of a polished surface and a reflective coating. The reflective coating may be a multilayer structure of UV transparent materials with high and low refractive index, each layer having an optical thickness of a quarter of the wavelength L of the electromagnetic radiation R.

The radiation source 4 and/or the incoupling arrangement 11 may be arranged adjacent a peripheral edge 12 of the electronic device 1, as shown in Fig. 2b.

The various aspects and implementations have been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

The reference signs used in the claims shall not be construed as limiting the scope. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this disclosure. As used in the description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.

Claims

1. A self-sanitizing electronic device (1) comprising:

-a surface element (2) comprising a device surface (2a),

-a waveguide structure (3) superimposed onto said device surface (2a) such that a main plane (PI) of said device surface (2a) and a main plane (P2) of said waveguide structure (3) extend in parallel, and

-a radiation source (4) configured to emit electromagnetic radiation (R) within an ultraviolet spectrum into said waveguide structure (3), said waveguide structure (3) comprising:

-a waveguide layer (5) having a first interface surface (5a) facing surrounding air and a second interface surface (5b) facing said device surface (2a), said waveguide layer (5) being configured to allow said electromagnetic radiation (R) to propagate within said waveguide layer (5) in a first direction (Dl) parallel with said main planes (PI, P2) so as to allow an evanescent field (F) generated by said electromagnetic radiation (R) to penetrate said first interface surface (5a) into said air, said evanescent field (F) sanitizing said first interface surface (5a).

2. The self-sanitizing electronic device (1) according to claim 1, wherein said waveguide structure (3) further comprises an adhesion layer (6) configured to adhere said waveguide structure (3) to said device surface (2a).

3. The self-sanitizing electronic device (1) according to claim 1 or 2, wherein a wavelength (L) of said electromagnetic radiation (R) is preferably between 100 and 400 nm, more preferably between 190 and 280 nm.

4. The self-sanitizing electronic device (1) according to claim 3, wherein an average penetration depth (d) of said evanescent field (F) into said surrounding air, from said first interface surface (5a), corresponds to said wavelength (L) within a range of 0.5L to 2L.

5. The self-sanitizing electronic device (1) according to any one of the previous claims, wherein said waveguide structure (3) further comprises a waveguide cladding layer (7) arranged between said second interface surface (5b) of said waveguide layer (5) and one of said device surface (2a) and said adhesion layer (6), said waveguide cladding layer (7) being configured to minimize absorption loss at said second interface surface (5b).

6. The self-sanitizing electronic device (1) according to claim 5, wherein said waveguide cladding layer (7) comprises at least one of CaF and MgF.

7. The self-sanitizing electronic device (1) according to any one of the previous claims, wherein said waveguide layer (5) comprises at least one of fused silica, spinel, sapphire, and CaC03.

8. The self-sanitizing electronic device (1) according to any one of the previous claims, wherein said waveguide structure (3) further comprises an electromagnetic radiation sensing arrangement (8) at least partially arranged between said second interface surface (5b) of said waveguide layer (5) and one of said device surface (2a) and said adhesion layer (6), preferably between said waveguide cladding layer (7) and said device surface (2a) or said adhesion layer (6), said sensing arrangement (8) being configured to detect electromagnetic radiation (R) within the ultraviolet spectrum and generate an indication that said electromagnetic radiation has been detected.

9. The self-sanitizing electronic device (1) according to claim 8, wherein said sensing arrangement (8) comprises a sensing layer (8a) and a photodetector (8b), said sensing layer (8a) being configured to generate electromagnetic radiation (R2) within the visible or near infrared spectrum, and transmit said visible or near infrared spectrum radiation (R2) to said photodetector (8b).

10. The self-sanitizing electronic device (1) according to any one of the previous claims, further comprising a control and monitoring system (9) operatively connected to said waveguide structure (3) and configured to control and/or monitor electromagnetic radiation (R) emitted by said radiation source (4).

11. The self-sanitizing electronic device (1) according to claim 10, wherein said surface element (2) comprises a user touch function (10), said control and monitoring system (9) being configured to deactivate said radiation source (4) in response to activation of said user touch function by a user, and/or in response to said photodetector (8b) detecting visible or near infrared spectrum radiation (R2).

12. The self-sanitizing electronic device (1) according to claim 10 or 11, wherein said control and monitoring system (9) is configured to modulate and/or filter signals generated by electromagnetic radiation detected by said sensing arrangement (8), such that signals corresponding to ambient electromagnetic radiation (R3) can be distinguished from signals corresponding to electromagnetic radiation (R) emitted by said radiation source (4).

13. The self-sanitizing electronic device (1) according to any one of the previous claims, wherein said waveguide structure (3) further comprises an incoupling arrangement (11), said incoupling arrangement (11) being configured to direct electromagnetic radiation (R) emitted by said radiation source (4) into said waveguide layer (5).

14. The self-sanitizing electronic device (1) according claim 13, wherein said incoupling arrangement (11) comprises at least one of a reflective surface, a grating coupler structure, or a prism structure.

15. The self-sanitizing electronic device (1) according to any one of the previous claims, wherein said surface element (2) is one of a display assembly and a back cover.

16. The self-sanitizing electronic device (1) according to any one of the previous claims, wherein said main plane (PI) of said device surface (2a) and said main plane (P2) of said waveguide structure (3) are identically curved adjacent at least one peripheral edge (12) of said electronic device (1).

17. The self-sanitizing electronic device (1) according to any one of the previous claims, wherein said electronic device (1) is one of a smartphone, tablet, wearable, key pad, button, or door handle.