WO2022208374A1

WO2022208374A1 - Sterilization apparatus

Info

Publication number: WO2022208374A1
Application number: PCT/IB2022/052926
Authority: WO
Inventors: Kwok Lit Chan; Fu Yuen FONG
Original assignee: Talentone Hong Kong Limited
Priority date: 2021-03-30
Filing date: 2022-03-30
Publication date: 2022-10-06
Also published as: CN117202830A

Abstract

A sterilization apparatus comprising a main housing and a sterilization arrangement is disclosed. The main housing includes a first surface through which sterilization energy is emitted from the sterilization arrangement. The sterilization arrangement is configured to activate to emit sterilization energy towards a second surface when separation between the first surface and the second surface is within a first separation distance.

Description

STERILIZATION APPARATUS

Field

[001] The present disclosure relates to sterilization apparatuses, and more particularly to sterilization apparatuses for use in cooperation with a suction head of a vacuum cleaner. The present disclosure also relates to a suction head comprising a sterilization apparatus.

Background

[002] Pathogens are health hazards and disinfection of pathogens on contaminated surfaces is highly desirable to mitigate infection. Pathogens on contaminated surfaces can be inactivated by disinfection energy such as direct heat or non-ionizing radiation such as UV radiation. Among the various disinfection energy, UVC, having a wavelength of between 100nm and 280nm, is known to be effective to harness microorganisms and coronaviruses, such as Sars. However. UVC is dangerous and direct exposure to UVC is hazardous to both human and animals.

Disclosure

[003] A sterilization apparatus comprising a main housing and a sterilization arrangement disposed on the housing is disclosed.

[004] The main housing includes a first surface through which sterilization energy is emitted from the sterilization arrangement.

[005] The sterilization arrangement is configured to activate to emit sterilization energy towards a second surface when separation between the first surface and the second surface is within a first separation distance.

[006] The sterilization arrangement may be configured to detect relative tilting between the first surface and the second surface, and to activate the sterilization arrangement to emit sterilization energy when the relative tilting between the first surface and the second surface is within a first angular range and when separation between the first surface and the second surface is within the first separation distance.

[007] The sterilization arrangement may be configured to not to emit sterilization energy when separation between the first surface and the second surface exceed a second separation distance, the second separation distance being same or different to the first separation distance.

[008] The sterilization arrangement may be configured to not to emit sterilization energy when relative tilting between the first surface and the second surface exceed within a second angular range, the second angular range being same or different to the first angular range. [009] According to another aspect of the present invention, there is provided a surface cleaning device comprising a housing including a first surface which is a lower surface, an ultraviolet (UV) light source which is configured to emit a sterilizing UV beam towards a second surface which is a surface to be cleaned; wherein the UV light source is configured to operate when the first surface and the second surface are in a predetermined relative spatial relationship; and wherein the cleaning device is configured to turn off the UV light source when the first surface is moved out of the predetermined relative spatial relationship.

[010] The predetermined relative spatial relationship may include a relative inclination, and wherein the cleaning device is configured to turn off the UV light source when the relative inclination between the first surface and the second surface exceeds a threshold inclination angle. The terms inclination and tilting are used interchangeably herein.

[011] The predetermined relative spatial relationship may include a separation distance, and wherein the cleaning device is configured to turn off the UV light source when minimum separation distance between the UV light source and the second surface exceeds a threshold separation distance.

[012] The UV light source may comprise a plurality of UVC LEDs, and wherein the LEDs are configured such that beams of adjacent LEDs overlap at the second surface.

[013] The cleaning device may have a first axis which is a centre axis defining a first direction, wherein the cleaning device is configured to move in a first direction to perform surface cleaning operations, and wherein the cleaning device is configured to detect tilting of the housing relative to the first axis.

[014] The UV light source may comprise an array of UVC LEDs, the array extending in a longitudinal direction which is orthogonal to the first direction.

[015] A suction inlet, a dirt outlet, and a suction passage interconnecting the suction inlet and the dirt outlet may be included on the main housing.

[016] The cleaning device may comprise a roller-brush which is disposed forward of the suction inlet.

[017] The cleaning device may be configured as a floor cleaning head and is configured for connection to a vacuum power source.

[018] The cleaning device may comprise a detection device which is configured to detect and determine the relative spatial relationship between the first surface and the second surface, and wherein the detection device is configured to turn off the UV light source when the first surface is moved out of the predetermined relative spatial relationship. [019] The detection device may comprise a controller which is configured to determine the relative spatial relationship between the first surface and the second surface with reference to detection signals received from the sensors, and wherein the controller is configured to turn off the UVC light source when the relative spatial relationship exceeds a predetermined turn off threshold.

[020] The turn-off threshold may include a separation distance exceeding a threshold distance and/or a threshold titling angle.

[021] The detection device may comprise a pair of infrared (IR) sensors, the IR sensors are provided on two opposite ends of the lower surface, wherein the UV light source comprises a UV light generation unit which is provided between the pair of IR sensors.

[022] The UV generation unit defines an effective disinfection region on the second surface where the UV generation unit provides sufficient energy for sterilization. The pair of IR sensors may be provided at a distance from the UV light generation unit such that a line passing through the IR sensor and orthogonal to the second surface is outside the effective region of the sterilizing UV beam on the second surface

[023] The UVC LED may have an output power of more than 12mW, including 15mW, 20mW, 30mW, 40mW, 50mW, 60mW, or more.

[024] The UV light source may be configured to emit a UV beam comprising a wavelength between 270-280nm.

[025] A cooling assembly may be provided inside the housing for cooling of the UV light source.

[026] The cooling assembly may comprise a heat sink and/or a cooling fan.

[027] The housing may comprise a top housing and a bottom housing, wherein the top housing comprises a metal mesh cover.

[028] A LED light bar may be provided at the front of the housing.

[029] There is also provided a surface cleaner comprising a vacuum cleaning device and the cleaning head. The cleaning head comprises a housing including a first surface which is a lower surface; an ultraviolet (UV) light source which is configured to emit a sterilizing UV beam towards a second surface which is a surface to be cleaned; wherein the UV light source is configured to operate when the first surface and the second surface are in a predetermined relative spatial relationship; and wherein the cleaning device is configured to turn off the UV light source when the first surface is moved out of the predetermined relative spatial relationship. Figures

[030] The disclosure will be described by way of example with reference to the accompanying Figures, in which:

Figures 1 A, 1 B, 1 C and 1 D are, respectively, top perspective view, top plan view, bottom plan view, and bottom perspective view of an example cleaning head of the present disclosure;

Figure 1 E is a partially exploded top perspective view of the cleaning head;

Figure 2 is a cross-sectional view of the cleaning head of Figure 1 (including Figures 1 A to 1 D) taken along an axis Y-Y’ and showing the cleaning head in operation contact with a target surface;

Figures 3A, 3B, 3C and 3D are, respectively, forward view, rear view, bottom view and rear perspective view of a sterilization module;

Figure 4 is an exploded view of the sterilization module of Figure 3 (including Figures 3A to 3D);

Figures 5A and 5B are example UVC light emitting diodes which are arranged as a sterilization energy source of the sterilization portion;

Figures 6A and 6B show, respectively, a suction head of a vacuum cleaner having a detachable light module attached to the forward end of its cleaning portion;

Figure 6C shows the suction head of Figure 6 (including Figures 6A and 6B) with the light module replaced by a sterilization module; and

Figure 7 is a bottom perspective view showing another example cleaning head of the present disclosure.

Description

[031] A cleaning head 10 of a vacuum cleaner comprises a cleaning portion 100 and a sterilization portion 200, as shown in Figures 1 A to 1 E. The cleaning portion 100 comprises a base portion on which a suction inlet 112 is disposed and a neck portion 114 which is connected to the base portion. The suction inlet 112 is disposed on a bottom surface of the cleaning portion 100 and the neck portion 114 comprises a tubular portion which is configured to connect the suction inlet 112 to an external suction power source to receive suction power so that a low-pressure suction region is created at the suction inlet 112 when the suction power source is in operation. The suction inlet 112 defines an entry aperture through which dust, debris or other loose solid wastes are to enter the cleaning portion 100 due to presence of suction power at the entry aperture. The cleaning head 100 optionally comprises a brush 116 which is disposed along the entry aperture of the suction inlet 112. The example suction inlet 112 defines an elongate entry aperture which extends in a transverse direction defined by a transverse axis X-X’ and the example brush is a motor driven rotary brush having a rotation axis which is parallel to the transverse axis X-X’. The cleaning head 10 is configured as a surface cleaner and the bottom surface of the cleaning head is configured to be in close proximity to or in abutment with a target surface to be cleaned during normal operations. The cleaning portion 110 is coupled to an external suction power source by means of the neck portion 114 and the neck portion 114 is connected to the base portion by an articulated joint. To receive electrical power and control signals to operate the cleaning head 10, power and signal connectors may be disposed at the neck portion to facilitate electrical connection with the corresponding power and signal connectors of the suction power source. In other embodiments, the cleaning head may have a built-in suction power source and a built-in controller which are housed inside the base portion so that the neck portion would no longer be required. The cleaning head 10 may be remote controlled and may comprise a wireless communication frontend to facilitate remote control data communication.

[032] The cleaning head 10 is configured to move in a forward direction which is defined by a forward axis Y Y’ during normal operations. The forward axis Y Y’ is orthogonal to the transverse axis X-X’. As shown in Figure 1C and 1 D, the cleaning head comprises a pair of rollers which is disposed at the rear end of the base portion 100A and the rollers have a roller axis which is parallel to the transverse axis X-X’.

[033] The sterilization portion 200 is configured to emit sterilization energy to sterilize the target surface before and/or after the target surface has been treated by the cleaning portion 100. To enable sterilization before and/or after treatment by the cleaning portion 100, the sterilization portion 200 may be forward and/or rearward of the cleaning portion 100.

[034] To enable delivery of sterilization energy to the target surface, the sterilization portion 200 comprise a sterilization energy source and a sterilization window through which sterilization energy emitted by the sterilization energy source is to pass from the sterilization portion 200 to the target surface. The sterilizing portion 200 may be configured as a sterilization module or as an integral part of the base portion 100A. The sterilization module may be permanently connected to the base portion 100A or may be detachably attached to the base portion 100A. The sterilization portion 200 comprises a disinfection arrangement which is configured to release disinfection energy to the target surface. The disinfection arrangement may comprise a non-ionic radiation source as a disinfection energy source. The non-ionic radiation source may be configured to generate a disinfection radiation which is within the UVC spectrum when activated. The disinfection energy source may be manually or automatically actuated. To facilitate manual operation, user control interfaces such as control buttons may be disposed on the main housing. To facilitate automatic operation of the disinfection arrangement, an on-board controller may be provided to execute stored instructions.

[035] During designed operations, the cleaning head 10 is placed on a target surface so that the cleaning portion including the rotary brush are in abutment with the target surface. The cleaning head 10 is devised such that when the cleaning portion 100 is placed on a target surface, the sterilization window of the sterilization portion is at a small separation distance d from the target surface, as shown in Figure 2.

[036] Referring to Figure 3 (including Figure 3A to 3D) and 4, an example sterilization portion 200 configured as a sterilization module 200A is shown. The sterilization module 200A comprises a main housing 210 which defines an internal compartment and a sterilization arrangement which is received inside the internal compartment. The sterilization arrangement is a disinfection arrangement which comprises a light source configured to emit UVC radiation for disinfection. The main housing 210 comprises a first surface which is a disinfection surface, a second surface which is a top surface, and a third surface which is a coupling surface that is configured for making mechanical coupling with the base portion of a suction cleaning head. The coupling surface interconnects the disinfection surface and the top surface and mechanical engagement means are disposed on the coupling surface for making detachable engagement with the base portion.

[037] The sterilization module 200A may comprise operation control arrangements which are configured to control operation of the sterilization arrangement. The control arrangement may comprise electronic circuitries, components, and/or devices which are configured to form a sensing arrangement for sensing separation distance between module 200A and the target surface, a sensing arrangement for sensing titling of the main housing relative to the target surface, and/or a decision arrangement configured for determining whether the separation distance between the sterilization module 200A and the target surface is within a prescribed distance range, and/or whether the relative tilting is within a prescribed angular range.

[038] The main housing 210 comprises a top housing portion (“top portion”) 212, a bottom housing portion (“bottom portion”) 214 and an intermediate housing portion (“intermediate portion”) which interconnects the top portion and the bottom portion. The intermediate portion comprises an upper intermediate housing portion 216A and a lower intermediate housing portion 216B. The housing portions 212, 214, 216A, 216B cooperate to define an internal compartment inside which the sterilization arrangement is received. The main housing 210 is elongate and has a width (measured in the transverse direction X-X’) which is significantly larger than its length (measured in the forward direction Y-Y’). [039] To control effective and safe operation of the sterilization energy source, the sensing arrangement may comprise one or a plurality of separation distance sensors. A separation distance sensor may be an optical sensor comprising an optical transmitter and an optical receiver which is configured to receive reflected optical signal originated from the optical transmitter. The optical transmitter may be an infrared transmitter and the optical receiver may be an infrared receiver configured to cooperate with the infrared transmitter.

[040] The decision arrangement may comprise electronic circuitries which are configured to determine separation distance between the sterilization window and the target surface with reference to the transmitted and received optical signals. A plurality of optical transmitters distributed around the sterilization window would help to improve distance measurement accuracy by mitigating errors due to tilting etc.

[041] The sensing arrangement may comprise a tilt sensor which is devised to measure tilting of the disinfection surface relative to the target surface to ensure even and/or uniform application of sterilization energy to the target surface.

[042] The decision arrangement may be configured to activate the sterilization energy source to emit sterilization energy if the separation distance between the sterilization window and the target surface is within a first separation distance and if the relative tilting is within a first angular range.

[043] The tilt sensor may be a stand-alone tilt sensor, for example a solid-state sensor. Alternatively, relative tilting may be determined with reference to the separation distance information obtained by the plurality of separation distance sensors with reference to optical signal reflection. To facilitate determination of separation distance and/or tilting, the sensing and decision arrangement may comprise comparators, sample-and-hold devices, logic circuits, logic arrays, microcontrollers and/or other peripheral circuits.

[044] The example sterilization energy source may be a UVC source. The UVC source may comprise a plurality of UVC LEDs and the UVC LEDs are arranged to form a distributed UVC disinfection energy source.

[045] Referring to Figure 4, a UV generation device 220 comprising a plurality of UVC light emitting diodes mounted on a circuit board 251 to form a UVC board, and a detection device comprising a plurality of optical sensors 230 is mounted inside the main housing. Each optical sensor 230 is mounted behind a lens 240 and the optical sensors 230 are distributed on two sides of the sterilization window. In some embodiments, the optical sensors 230 may be distributed to surround the sterilization window and the optical sensors 230 may be spread as far as possible to enhance measurement accuracy. [046] The UV generation device 220 is configured to generate UV sterilizing radiation onto the surface to be sterilized. In the present example the UV generation device 220 comprises an ultraviolet lamp, or preferably, an ultraviolet light-emitting diode (UV-LED). The UV-LED is configured to produce rays having UV-C wavelengths (200 nm - 280 nm). In some examples, the UV beam has a wavelength in the higher range between 270-280nm. The rays are directed at the target surface to render pathogens such as viruses, bacteria and other pathogens harmless in seconds, for example, a few second.

[047] The UV generation device 220 can comprises multiple UV light sources for adjust the light output and the spatial distribution of illumination. In the present example, the UV generation device 220 comprises an array of three UV-LEDs arranged linearly along a direction parallel to the first axis X-X’. There are three UV-LEDs in the array, but other numbers of LEDs may be used without loss of generality.

[048] An example specification of the UV-LED is set out in the table below.

[049] The UV generation device 220 is arranged to be in close proximity to the floor in an operation position. UV intensity is inversely proportional to the square of the distance so it decreases at longer distances. By arranging the UV generation device 220 at a very short distance from the floor, for example between 1 5mm and 15mm, the efficiency in killing germs is improved.

[050] Optical arrangements may be provided to optimize the intensity of light and improves the sterilization efficiency.

[051] The detection device 230 is configured to detect the presence of an object within the field of the detection device 230, thereby ascertaining the presence of the surface to be cleaned is within a certain distance (d) from the sterilizing module 200A. The detection device 230 may comprises laser sensor, infrared (IR) sensor, ultrasonic sensor, tilt sensor or any proximity sensor that provides signal when the detection device 230 moves towards or away from the surface immediate in front of the detector.

[052] In the present example, the detection device 230 comprises a pair of IR sensors. The IR sensor may be an active infrared sensor, which emits and detects infrared radiation. The IR sensor has two parts: a light emitting diode (LED) and a receiver. When an object comes close to the sensor, the infrared light from the LED reflects off of the object and is detected by the receiver. In such circumstance, the detection device 230 is configured to detect the presence of an object. On the other hand, when an object moves away from the sensor for a distance exceeding a threshold, the infrared light from the LED reflects off of the object would not be detected by the receiver. As a result, the detection device 230 does not detect the presence of an object. The two IR sensors are mounted at two longitudinal ends of the housing 210 of the sterilizing module 200A. The UV generation device 220 is mounted midway between the pair of IR sensors. The UV generation device 220 is configured to turn off when either one of the pair of IR sensors does not detect the presence of an object. In other words, the UV generation device 220 is turned on only when both ends of the housing 210 of the sterilizing module 200A are on the surface to be cleaned. This ensure the UV light generated is directed towards the surface (the floor in this case), and so the sterilizing module 200A is at a safe position for operation.

[053] The UV generation device 220 will produce a substantial amount of heat while in operation. UV-LED emits light at the front surface of the LED and heat at its back surface. A cooling assembly is provided inside the housing 210 of the sterilizing module 200A for dissipating the heat away. The cooling assembly comprises a heat sink 242 and at least one cooling fan 244. The heat sink 242 is configured to transfer the heat generated by UV generation device 220 to the surroundings, often air. The heat sink 242 may be arranged to be at the back surface of the UV-LED to conduct the heat it generated effectively. The cooling fan 244 is arranged to improve ventilation next to the heat sink 242, so as to improve heat dissipation. The cooling fan 244 may be arranged next to the heat sink 242 to blow fresh air towards the heat sink 242. The top housing portion 212 comprises a metal mesh plate 213 to enhance heat transfer from inside to outside of the housing 210.

[054] The sterilizing module 200 comprises a control board 250 and a UVC board 251 . The control board 250 comprises a microprocessor. The UVC board 251 which is configured to turn the UV generation device 220 on/off. The microprocessor is configured to receive information from the control button and the detection device 230. Based on the information from the detection device 230, the microprocessor determines if the UV generation device 220 is directed towards a surface or if the UV generation device 220 is at a distance away from the surface within a predetermined value. When the microprocessor determines that the UV generation device 220 is not directed towards a surface or the UV generation device 220 is at a distance from the surface greater than a predetermined value, the microprocessor instructs the UVC board 251 to turn off the UV generation device 220.

[055] The predetermined value may be predetermined taking into account the distance required for effective sterilization and disinfection by UV light and the thickness of body part, for example fingers, required for protection purpose. The predetermined value includes a threshold separation distance and a threshold tilting angle. The threshold separation distance may be 5mm, 10mm, 15mm, 20mm, or a range or ranges selected from a combination any of the aforesaid distance values. The threshold tilting angle may be ±10°, ±15°, ±20°, or a range or ranges selected from a combination any of the aforesaid angle values. During operation, the cleaning head is repeatedly removed away from the floor by lifting upward or tilting at an angle. In both movements, the distance between the detection device 230 and the floor increases. When the distance and the angle between the cleaning head and floor exceed the threshold separation distance and the threshold tilting angle, the detection device 230 cannot detect the infrared light reflected off from the floor. Thus, the detection device 230 does not detect the presence of the floor. The UV generation device 220 is therefore turned off. In the present example, the threshold separation distance is 15mm and the threshold tilting angle is 20°.

[056] A light indicator 260 is provided on the housing 210 of the sterilizing module 200. A light belt 261 , which is mounted on a light guide 262, is placed behind the light indicator 260. The light belt 261 is for example a LED, which acts as a light source for the light indicator 260, and is turned on when the UV generation device 220 is turned on. This alerts the user and people around that the UV generation device 220 is in operation.

[057] A lighting device 270 is provided at the front of the housing 210 of the sterilizing module 200. It functions to help user to spot dust and debris in dark conners or under furniture. The lighting device 270 comprises a soft LED light bar 271 and a soft light bar cover 272. Apart from shining light, the soft LED light bar 271 and the soft light bar cover 272 also act as a bumper, to absorb impact in a minor collision.

[058] The arrangements of the UV-LEDs are discussed in more details with reference to Figures 5A and 5B. The UV-LEDs are evenly spaced, and each UV-LED is separated from the adjacent UV-LED by 6-7 mm, and more specifically, by 6.7mm. The distribution of radiant flux is continuous. The UV-LEDs provides radiant flux to the surface to be cleaned in a range of 17 to 24 mW/cm² at a distance from 1.0mm to 2.0mm., and there is no intermediate area receiving insufficient energy to kill germ. The UV generation device 220 defines an effective region on the surface where the surface receives a radiant flux that is sufficient to sterilize the surface.

[059] Figures 5A and 5B show example arrangements of UVC LED on the UV generation device 220. An UV-LED with the below specification is incorporated.

[060] The UV-LEDs of Figure 5A are arranged in a line. The UV-LEDs of Figure 5B are arranged into a matrix with two rows and three columns. The rows are separated by 4-5mm, and more specifically, by 4.5mm. The columns are separated by 6-7mm, and more specifically, by 6.7mm. The separation of the UV-LED, coupled with the increase in the number of UV- LEDs and the power of individual UV-LED, results in a continuous radiant flux distribution to the surface to be cleaned in a range of 59 to 73 mW/cm² at a distance from 1.0mm to 2.0mm. In general, the LEDs are arranged such that the disinfection beam of one LED overlaps with the disinfection beam of an adjacent LED to create a disinfection region on the target surface, and the disinfection region on the target surface has a minimum power level sufficient for disinfection.

[061 ] Referring to Figure 3, where the sterilizing portion 200 is configured to be a detachable module for detachable attachment to the base portion 100, a positioning device 218 and an electrical terminal 280 are provided in the sterilizing module 200, and more particularly, on the surface of the housing 210 facing the base portion 100. The positioning device 218 is a plastic lump in this example. The electrical terminal 280 are configured to receive power from the base portion 100 and / or to exchange information with the base portion 100. The sterilizing module 200 further comprises locks to secure the module to the base portion 100.

[062] Figures 6A and 6B show another cleaning head with a detachable light module 400.The base portion 100 of the cleaning head comprises an electrical terminal 110 and a guiding slot 120. The electrical terminal 110 is configured to provide power to module attached to the base portion and/or to exchange information with the sterilizing module 200. The guiding slot 120 is configured to guide the module into a correction position. The detachable light module 400 comprises a light module release button 410. The detachable light module is released from the base portion 100 by pressing the light module release button 410. The power port 110 and the guiding slot 120 are exposed when the detachable light module 400 is removed.

[063] Figure 6C shows the example sterilizing module 200A readily connectible to the example cleaning head of Figure 6B. The sterilizing module 200 is attached to the base portion 100 by inserting the positioning device 218 into the guiding slot 120. The electrical terminal 110 of the base portion 100 of the cleaning head is in contact with the electrical terminal 280 of the sterilizing module 200. When the user turns on the UV generation device 220 by pressing a control button on the vacuum cleaner, a control signal is transferred from the electrical terminal 110 of the base portion to the electrical terminal 280 of the sterilizing module 200. The control signal is then transferred to the control board 250, which turn on the UV generation device 220. The sterilizing module 200 further comprises a sterilizing module release button 290, which is mounted on a sterilizing module release button holder 291 . The sterilizing module 200 is released from the base portion 100 by press the sterilizing module release button 290.

[064] Figure 7 shows another cleaning head 500 according to the present invention. The cleaning head 500 comprises a base housing and a roller cleaner 510 attached to a front portion of the base housing. A UV generation device 520 is provided at a back portion of the base housing. When a user pushes the cleaning head 500 forward, the surface is cleaned by a cleaning medium on the roller cleaner 510 before being sterilized. The UV generation device 520 comprises UV-LEDs embedded inside the base housing. In this way, the UV-LEDs are protected from accidental damage when the cleaning head 500 is in abutment contact with the surface to be cleaned.

[065] While the disclosure has been described herein with reference to examples, the examples are not intended and should not be used to limit the scope of disclosure.

Claims

1. A sterilization apparatus comprising a main housing and a sterilization arrangement disposed on the housing, wherein the main housing includes a first surface through which sterilization energy is emitted from the sterilization arrangement, and

- wherein the sterilization arrangement is configured to activate to emit sterilization energy towards a second surface when separation between the first surface and the second surface is within a first separation distance.

2. The apparatus of claim 1 , wherein the sterilization arrangement is configured to:

- to detect relative tilting between the first surface and the second surface, and

- to activate the sterilization arrangement to emit sterilization energy when the relative tilting between the first surface and the second surface is within a first angular range and when separation between the first surface and the second surface is within the first separation distance.

3. The apparatus of claims 1 or 2, wherein the sterilization arrangement is configured to not to emit sterilization energy when separation between the first surface and the second surface exceed a second separation distance, the second separation distance being same or different to the first separation distance.

4. The apparatus of any preceding claims, wherein the sterilization arrangement is configured to not to emit sterilization energy when relative tilting between the first surface and the second surface exceed within a second angular range, the second angular range being same or different to the first angular range.

5. The apparatus of any preceding claims, comprising sensing circuitries which are configured to detect separation distance between the first surface and the second surface and/or tilting of the first surface relative to the second surface.

6. The apparatus of any preceding claims, comprising decision circuitries which are configured:

- to determine separation distance between the first surface and the second surface;

- to activate the sterilization arrangement to emit sterilization energy towards the second surface when the separation distance between the first surface and the second surface is at or below the first separation distance; and

- to deactivate the sterilization arrangement to not to emit sterilization energy towards the second surface when the separation distance between the first surface and the second surface exceeds the first separation distance.

7. The apparatus of any preceding claims, comprising decision circuitries which are configured:

- to determine relative tilting between the first surface and the second surface;

- to activate the sterilization arrangement to emit sterilization energy towards the second surface when the relative tilting is within the first angular range; and

- to deactivate the sterilization arrangement to not to emit sterilization energy when the relative tilting between the first surface and the second surface is outside the first angular range.

8. The apparatus of any preceding claims, wherein the apparatus comprises sensing and decision circuitries including a plurality of optical sensors, wherein the optical sensor comprises an infrared transmitter and a corresponding infrared receiver which is configured to receive reflected infrared originated from the infrared transmitter, and wherein the sensing and decision circuitries are configured to determine separation distance between the first surface and the second surface with reference to separation distance information received from the plurality of optical sensors.

9. The apparatus of any preceding claims, wherein the main housing is configured to move along the second surface in a first direction, and wherein the sterilization arrangement is configured to emit sterilization energy in a second direction which is orthogonal to the first direction.

10. The apparatus of any preceding claims, wherein the main housing is configured to be in physical contact with the second surface during operation, and the first surface is elevated above the second surface when the main housing is in contact with the second surface such that the first surface is in proximity to and oppositely facing the second surface.

11 . The apparatus of any preceding claims, wherein the first separation distance is 20mm or less, including 18mm, 16mm, 14mm, 12mm, 10mm, 8mm, 6mm, or a range or ranges selected by combination of any of the aforesaid values.

12. The apparatus of any preceding claims, wherein the first angular range is ±20°or less, including ±19°, ±18°, ±17°, ±16°, ±15°, ±14°, ±13°, ±12°, ±11 °, ±10°, or a range or ranges selected by combination of any of the aforesaid values.

13. The apparatus of any preceding claims, wherein the sterilization arrangement is configured to emit sterilization energy in the form of steam and/or UVC radiation when activated.

14. The apparatus of any preceding claims, wherein the sterilization arrangement is configured to deliver UVC radiation having a power density of up to 150mJ/cm² on the second surface, and wherein the power density on the second surface is at 1mJ/cm², 2mJ/cm², 5mJ/cm², 10mJ/cm², 15mJ/cm², 20mJ/cm², 25mJ/cm², 30mJ/cm², 35mJ/cm², 40mJ/cm², 50mJ/cm² or above, or a range or ranges selected by combination of any of the aforesaid values.

15. The apparatus of any preceding claims, wherein the sterilization arrangement comprises a plurality of LED which is configured to emit a band of UVC sterilization energy, and wherein the LED are arranged such that the sterilization energy emitted by one LED overlaps with the sterilization energy emitted by an adjacent LED.

16. The apparatus of any preceding claims, wherein the apparatus comprises mechanical coupling means and electrical connection means which are provided to enable attachment of the apparatus to a mobile platform, wherein the mobile platform is configured to supply electrical power to the apparatus when the apparatus is mechanically coupled to the mobile platform, and wherein the mechanical coupling means and electrical connection means are formed on a coupling surface of the main housing, the coupling surface being adjacent to the first surface.

17. A suction head of a vacuum cleaner, comprising a cleaning portion and a sterilization portion, wherein the sterilization portion is the apparatus of any preceding claims.

18. The suction head of claim 17, wherein the sterilization portion is configured to obtain electrical power to generate sterilization energy from the vacuum cleaner via the cleaning portion.

19. The suction head of claims 17 or 18, wherein the sterilization portion is a sterilization module attachable to the cleaning portion by snap-fit connection.

20. The suction head of any of the preceding claims, wherein the cleaning portion comprises a suction inlet having an elongate entry aperture which extends along a transverse axis, and a brush which is disposed inside and along the entry aperture; wherein the cleaning portion is devised to move in a forward direction which is orthogonal to the transverse axis, and wherein the sterilization portion is on a forward end or a rearward end of the cleaning portion.