WO2024153855A1

WO2024153855A1 - An apparatus and a method for a camera

Info

Publication number: WO2024153855A1
Application number: PCT/FI2024/050013
Authority: WO
Inventors: Kimmo Jokinen
Original assignee: Tecgyver Innovations
Priority date: 2023-01-17
Filing date: 2024-01-15
Publication date: 2024-07-25

Abstract

The invention relates to an apparatus and a method to prevent dirt entering a vehicle camera. The camera has a lens. The apparatus comprises an input for receiving a flow of gas; a chamber for directing the flow of gas to pass in front of the lens of the vehicle camera; one or more channels for leading the gas from the input to the chamber; and an output orifice associated with the chamber for leading gas away from the lens to atmosphere. The method comprises receiving a flow of gas by an input of an apparatus; leading the flow of gas to a chamber of the apparatus; directing the flow of gas by the chamber to pass in front of the lens of the vehicle camera; and leading the flow of gas away from the lens to atmosphere.

Description

An Apparatus and a Method for a Camera

Technical field

This invention relates to an apparatus for preventing dirt to enter a surface of a lens of a camera of a vehicle. The invention also relates to a method for preventing dirt enter a surface of a lens of a camera of a vehicle.

Background

In a modern vehicles several camera units are used to provide different views for a driver of the vehicle and for some automatic control operations. For example, many vehicles have a camera installed at a back to provide better visibility than mirrors to a driver during back up of the vehicle. There may be person(s) and/or object(s) at the backside of the vehicle which the mirrors of the vehicle are not able to show to the driver. Therefore, using the camera at the back of the vehicle may be able to show the driver those persons and objects not visible via the mirrors.

Cameras are also used in many vehicles to help autonomous driving, to provide collision prevention and for other purposes. For example, there may be a camera which a control device of the camera uses to detect whether usage of low beams are needed, for example when there is another vehicle in the front nearby, or whether long distance lights could be used without a risk to dazzle other drivers. Also a collision prevention system may use one or more cameras to determine if the vehicle is approaching another vehicle too close.

In the above kinds of situations the existing camera systems may be disturbed by dirt, water, moisture etc. which has stuck to the surface of a camera lens.

Some prior art systems and methods use a strong jet of water directed towards the surface of the lens to clean it up. This kinds of systems disturb the view during the washing phase and usually do not manage to take away all dirt which have been strongly stuck on the camera lens. Another drawback is that there has to be a reservoir for the cleaning water and it has to be filled when empty. Another known method is to clean the camera lens manually every now and then. This has the drawback that the cleaning causes wear of the surface of the camera lens and it may become blurred wherein the visibility through the camera lens is reduced. Furthermore, this kind of cleaning cannot be performed during driving but the vehicle has to be stopped before the camera lens can be cleaned manually.

Blurred or dirty cameras may also cause security risks such as failing to detect a pedestrian, another vehicle or an object in front of the vehicle while it is driving autonomously. Hence, a collision may be a consequence from the detection failure. On the other hand, a result may also be that a false detection is generated when there actually is no risk of collision, but the vehicle may still be stopped by the control system of the vehicle.

Summary

It is an aim of this invention to overcome the drawbacks of existing systems and methods and provide an improved apparatus and method for keeping camera lenses of a vehicle free of dirt.

The invention is based on the idea that dirt is prevented to reach the surface of the camera lens in the first place. This may be achieved by creating a flow of gaseous medium passing by the surface of the camera lens. The gaseous medium is, for example, air. The flow of gaseous medium, which will also be called as a gas flow in this specification, is directed in front of the camera lens and further onwards away from the camera lens so that it flows away from the camera.

Some non-limiting examples of vehicles in which such apparatus, method and system may be utilized are a car such as a passenger car, a bus, a tram, a lorry, an excavator, a truck, a forest machine, a bucket loader, etc.

According to a first aspect there is provided an apparatus for a vehicle camera having at least a frontmost lens and an iris in front of the frontmost lens, the apparatus comprising: an input for receiving a flow of gas; a wall, which together with an outer surface of the vehicle camera form a chamber for directing the flow of gas to pass in front of the iris of the vehicle camera; one or more channels for leading the gas from the input to the chamber; and an output orifice associated with the chamber for leading gas away from the lens to atmosphere, wherein the chamber is configured to lead the flow of gas to a front of the vehicle camera and further away from the vehicle camera.

In accordance with an embodiment, the apparatus comprises an input pipe for providing gas to the chamber.

In accordance with an embodiment, the apparatus comprises a compressor for producing compressed air; and a pipe coupled between the compressor and the input pipe for leading compressed air from the compressor to the input.

In accordance with an embodiment, the apparatus comprises a wall in the chamber to divide the chamber to at least a first section and a second section.

In accordance with an embodiment, the apparatus comprises a flange in the chamber to tighten the chamber at the end opposite to the output orifice.

In accordance with an embodiment, the apparatus comprises a heating arrangement for warming at least a part of the apparatus.

In accordance with an embodiment, the apparatus comprises a vibrating structure to extract particles away from the chamber of the apparatus.

In accordance with an embodiment, the vibrating structure comprises a protective sheet in front of the lens; and a piezo element to induce vibrations on the protective sheet.

According to a second aspect there is provided a method for preventing dirt entering a surface of at least a frontmost lens of a vehicle camera having an iris in front of the frontmost lens, the method comprising: receiving a flow of gas by an input of an apparatus; leading the flow of gas to a chamber of the apparatus formed by a wall together with an outer surface of the vehicle camera; directing the flow of gas by the chamber to pass in front of the iris of the vehicle camera; and leading the flow of gas away from the lens to atmosphere. In accordance with an embodiment, the method comprises producing compressed air; and leading compressed air from the compressor to the chamber.

In accordance with an embodiment, the method comprises directing the flow of gas by the chamber to front of the iris.

In accordance with an embodiment, the method comprises tightening the chamber at the end opposite to the output orifice.

In accordance with an embodiment, the method comprises warming at least a part of the apparatus.

In accordance with an embodiment, the method comprises providing gas to at least a first section and a second section of the chamber.

In accordance with an embodiment, the method comprises providing gas to the apparatus based on movement of the vehicle camera.

In accordance with an embodiment, the method comprises using the output orifice of the apparatus as an iris of the vehicle camera.

In accordance with an embodiment, the method comprises producing ultrasonic vibrations to extract particles away from the chamber of the apparatus.

According to a third aspect there is provided an apparatus for a vehicle camera having a lens, the apparatus comprising: means for receiving a flow of gas; means for the flow of gas in front of the lens of the vehicle camera; means for leading the gas from the input to the chamber; and means for leading gas away from the lens to atmosphere.

In accordance with an embodiment, the apparatus comprises means for providing gas to the chamber.

In accordance with an embodiment, the apparatus comprises means for producing compressed air; and means for leading compressed air from the compressor to the chamber. In accordance with an embodiment, the apparatus comprises means for dividing the chamber to at least a first section and a second section.

In accordance with an embodiment, the apparatus comprises means for tightening the chamber at the end opposite to the output orifice.

In accordance with an embodiment, the apparatus comprises means for warming at least a part of the apparatus.

In accordance with an embodiment, the apparatus comprises means for providing gas to the apparatus based on movement of the vehicle camera.

In accordance with an embodiment, the apparatus comprises means for using the output orifice of the apparatus as an iris of the vehicle camera.

In accordance with an embodiment, the apparatus comprises means for producing ultrasonic vibrations to extract particles away from the chamber of the apparatus.

According to a fourth aspect there is provided a system comprising the apparatus and the vehicle camera.

In accordance with an embodiment, the system comprises a compressor for producing compressed air for the apparatus.

Brief description of the drawings

In the following details of some embodiments are described with reference to the appended drawings, in which

Fig. 1 a depicts as a simplified view a cross section of an apparatus, in accordance with an embodiment;

Fig. 1 b depicts as a simplified view a cross section of a camera;

Fig. 1 c depicts as a simplified view a cross section of the apparatus of Fig. 1a and the camera of Fig. 1 b, in accordance with an embodiment;

Fig. 1 d depicts as a simplified view a cross section of the apparatus of Fig. 1 a from a top, in accordance with an embodiment; Fig. 1e depicts as a perspective view an apparatus, in accordance with an embodiment;

Fig. 1f depicts as a perspective view a camera;

Fig. 2 depicts as a simplified view an example of the apparatus and an air compressor, in accordance with an embodiment;

Fig. 3 depicts as a simplified view a cross section of an apparatus, in accordance with another embodiment;

Fig. 4a illustrates flow of air in a chamber of the apparatus, in accordance with an embodiment;

Fig. 4b illustrates flow of air in a chamber of the apparatus, in accordance with another embodiment;

Fig. 5a illustrates yet another embodiment in which the apparatus is equipped with a heating arrangement;

Fig. 5b illustrates another embodiment of the apparatus is equipped with the heating arrangement;

Fig. 6 illustrates a camera having an iris and an entrance aperture at front of a frontmost lens;

Fig. 7a illustrates still another embodiment in which the apparatus is equipped with a vibrating element;

Fig. 7b shows a simplified electric block diagram of the vibrating structure, in accordance with an embodiment; and

Figs. 8a and 8b illustrate yet another embodiment of the apparatus.

Detailed description

An embodiment of an apparatus 10 is depicted as a simplified, cross sectional view in Fig. 1 a, whereas Fig. 1 b illustrates as a simplified, cross sectional view of a vehicle camera 20. In these figures only some details of the apparatus 10 and the camera 20 are shown. In the example of Fig. 1 c the apparatus 10 of Fig. 1 a has been installed in connection with a vehicle camera 20 of Fig. 1 b.

The vehicle camera 20 will also be called as a camera 20 in this specification.

The apparatus 10 comprises a chamber 11 in front of the camera 20. The chamber 11 is formed by a wall 17, for example, which forms an outer wall of the chamber. An inner wall of the chamber is defined by an outer surface 22a of a casing 22 of the camera 20 or a part of it. The apparatus 10 also comprises an input 12 for receiving gas, such as air, which will be used to prevent dirt entering the camera 20 or a lens 21 of the camera 20. The input 12 and the chamber 11 are coupled with a gas channel 13 wherein gas entering the apparatus 10 via the input 12 can flow to the chamber 11 via the gas channel 13. It should be noted that in some embodiments the chamber 11 and/or the gas channel 13 and/or the input 12 are actually implemented so that there are no clear borders between those elements. Still, gas is received by some kind of input section and flowing via some kind of channelling to the front of the camera 20 and further away from the camera 20 and the apparatus 10, as will be described later in this specification.

In the embodiment of Figs. 1a and 1 c the apparatus 10 comprises a pipe 14 as the gas channel 13, wherein an outer end 14a of the pipe 14 operates as the input 12. The other end 14b of the pipe is coupled with to the chamber 11 . The chamber 11 surrounds a part of an outer surface of the camera 20 so that there is a small gap 30 between the outer surface of the camera and the inner surface of the chamber 11 . The chamber 11 has an orifice 15 so that, on one hand, the chamber 11 does not block the field of view of the camera 20 and, on the other hand, gas can exit the chamber 11 to atmosphere 40. Opposite to the orifice 15 the chamber 11 circumvents the outer surface of the camera to prevent gas leaking to the opposite direction. In this embodiment this is implemented with a flange 16 in the chamber 11 . If necessary, there may also be a gasket between the camera 20 and the flange 16 to provide more tightness against gas and moisture.

The diameter of the output orifice 15 can be, for example, only a few millimeters, such as in the range of 2 to 5 mm, preferably about 3 mm. This kind of small diameter can have the effect that the pressure of the gas need not be so high than if orifice having larger diameter were used. Hence, smaller compressors 18 can be used and noise may also be lower than with compressors of higher output pressure. Gas can be provided to the apparatus 10 from a compressed air piping (not shown) of the vehicle, for example.

The camera 20 has a casing 22 in which one or more lenses 21 have been installed. In front of the camera 20 there is one iris 23 via which light can enter the camera 20. The one or more lenses 21 are in an optical path of the camera towards a sensor element 24 in which an optical image provided by the light entering the camera is converted to electric signals (pixels). The operation of the camera 20 is not relevant in this connection and will not be discussed in more detail.

In addition to the iris 23 there may also be an aperture 27 (a.k.a. entrance aperture) at the front of the iris 23, or if the iris 23 is behind a frontmost lens 21 , the entrance aperture 27 is then located at the front of the frontmost lens 21. The term frontmost lens means in this specification that lens which is farther from the sensor 24 and therefore closest to the output orifice 15 of the apparatus 10 when the apparatus 10 is attached with the camera 20. Fig. 6 illustrates a camera 20 having the iris 23 and the entrance aperture 27 at front of the frontmost lens 21 .

The casing 22 has a peak 25 having a triangular cross section. The tip of the peak has a hole forming the iris 23. Three of the lenses 21 behind the iris 23 are illustrated in Fig. 1 b but there may also be less than three lenses or more than three lenses in the camera casing 22. This kind of camera 20 has a relatively large field-of-view (FOW), which is illustrated with the dotted lines 26 in Fig. 1 b.

Cameras 20 having a small iris 23 in the front have also been called as pinhole cameras, although the term pinhole camera has originally been used for a camera having a small hole operating as a lens.

In accordance with an approach, the outer surface 22a of the camera is a truncated cone.

In accordance with an embodiment, the inner surface of the wall 17 resembles the form of the outer surface of the camera casing 22 so that there is a small gap 30 between the wall 17 and the casing 22. Fig. 1 e shows a perspective view of the example of the apparatus 10 of Fig. 1 a, and Fig. 1f shows a perspective view of the example of the vehicle camera 20 of Fig. 1 b. Fig. 2 illustrates another embodiment of the apparatus 10. In this embodiment, there is also a gas compressor 18 for providing compressed gas. The compressed gas is directed to the input 12 of the apparatus 10 via a pipe

19, wherein the compressed gas can flow to the channel 13 and further to the chamber 11 and out to the atmosphere 40.

The compressor 18 is, for example, a type which is powered from a battery of a vehicle and may be controlled 51 by a controller 50 or the compressor may be switched on when electricity of the vehicle is switched on, and switched of when electricity of the vehicle is switched off.

In accordance with an approach, the compressed air can be produced by a vehicle’s compressor when the vehicle is equipped with such compressor. Some vehicles may utilize the vehicle's compressor with suspension and possibly for some actuators in the vehicle.

The compressed air may be filtered from possible impurities and some humidity removed before the compressed air can be used with the apparatus to avoid dirt and/or moisture attaching the surface of the lens 21 of the camera

20.

Fig. 3 illustrates yet another embodiment in which air flow during movement of a vehicle (not shown) is utilized as the cleaning gas. In other words, there is no compressor or other actively gas flow generating equipment. This kind of alternative can be called as a passive system whereas the system using specific equipment for generation of the gas flow can be called as an active system. The apparatus 10 has, for example, a circular orifice or another kind of air flow guidance element as the input 12 so that when the vehicle is moving air can flow via the input into the channel 13 and further to the chamber 11 . Air can exit the chamber 11 through the output orifice 15. Arrows 60 illustrate movement of air inside the apparatus.

In the following the operation of the apparatus 10 will be explained, in accordance with an embodiment. In this embodiment air is used as compressed gas but basically the same principles are applicable with passive systems and/or using other substance than air as the compressed gas or using a mixture of air and some other gaseous substance(s). The compressed air is flowing via the input 12 to the gas channel 13 and further to the chamber 11. Because the pressure of the air is higher in the chamber 11 than in the atmosphere the air flows towards the orifice 15 and via the orifice 15 to the atmosphere 40. The pressure of the air at the orifice 15 prevents or at least remarkably decreases dirt entering the chamber 11 via the orifice 15. Therefore, dirt will not cover the surface of the lens 21 of the camera 20. In the same way the pressure prevents water entering the chamber 11 . Based on the above described operation the lens 21 of the camera 20 remains substantially clean and without dirt and other substances which could affect visibility through the lens 21 .

Fig. 4a illustrates flow of air in the chamber 11 of the apparatus 10, in accordance with an embodiment. The arrows 60 show how air can enter the chamber 11 and begin to flow upwards between the camera surface 22 and the wall of the chamber 11. It should be noted that the arrows do not necessarily show the actual flow but provide some illustration of that.

Fig. 4b illustrates flow of air in the chamber 11 of the apparatus 10, in accordance with another embodiment. In this embodiment the chamber 11 is divided into two sections 11 a and 11 b by a wall 11 c. This may improve the flow 60 so that it will be divided more evenly along the chamber 11 .

The examples of Figs. 4a and 4b are only for illustration purposes and the chamber 11 may also be implemented in some other forms and structures. It is also possible that the gap 30 between the apparatus 10 and the camera 20 need not be substantially constant as shown in Figs. 1 a, 1 c, 2 and 3 but may be different at different locations. For example, the cross section of the chamber 11 may be a square therein the gap is larger near the top of the camera 20 than at the bottom of the chamber 11 .

It should be noted that the figures do not show any fixing arrangement for the apparatus 10 and the camera 20 but only such details which help a skilled artisan understand the invention. As a further note, details of the apparatus 10 and the camera 20 may vary from those illustrated in the figures.

The apparatus 10 may be manufactured in many different ways and using different materials. As an example, the apparatus 10 may be printed using three-dimensional printing machine (3D printer). The material may be metal, plastics or so called composite (a mixture of plastic and wood). Another manufacturing option is to use a mould.

In accordance with an embodiment the apparatus 10 and the casing 22 of the camera are formed together so that they are one piece to be attached with other parts of the camera 20.

Fig. 5a illustrates yet another embodiment in which the apparatus 10 is equipped with a heating arrangement 70 to increase the temperature of some parts of the apparatus 10. In this example embodiment the heating arrangement is attached with the casing, in front of it but also other places may be suitable for providing heating, for example embedded in the casing. One purpose of the heating is to prevent at least the output orifice 15 freezing and/or collecting moisture. Ice, salt and moisture may negatively affect the quality of images formed by the camera.

Providing the heating in connection with the apparatus 10 (e.g. on nontransparent parts) instead of the camera 20 (in connection with transparent lens(es)) has the advantage that the generated heat does not warm the camera 20 and thus reduces the risk of dirt, salt etc. harmful substances drying on the surface of the lens 21 .

Fig. 5b illustrates another embodiment of the apparatus 10 equipped with the heating arrangement 70. In this alternative embodiment the heating arrangement 70 is installed inside the chamber 11 , on the wall of the chamber 11.

It should be noted that the locations of the heating arrangement 70 depicted in Figs. 5a and 5b are just illustrative but the locations may be different in different embodiments. It may also be possible to implement the heating arrangement 70 both inside the chamber 11 and in front of the casing.

Fig. 7a illustrates an embodiment in which the apparatus 10 is equipped with a vibrating structure 80 to extract particles such as dirt, water, dust, sand etc. from a surface of the lens of the apparatus 10, and Fig. 7b shows a simplified electric block diagram of the vibrating structure 80. In this example embodiment the apparatus 10 may comprise similar elements than e.g. the embodiment of Fig. 1 and additionally the vibrating structure 80 in front of that lens which is the frontmost (a.k.a. outermost) lens of the one or more lenses 21 of the camera 20. The vibrating structure 80 comprises in this embodiment a piezo element 81 mechanically coupled with a protective sheet 82, which is at least partly transparent so that light can pass to the frontmost lens 21a and further to the sensor 24 of the camera 20. Vibrations of the piezo element 81 induce vibrations to the protective sheet 82. The protective sheet 82 may have a certain resonance frequency, wherein when the piezo element 81 vibrates at or near the resonance frequency of the protective sheet 82, a so called standing wave (also known as a mode) may be induced to the protective sheet 82.

In accordance with an embodiment, the piezo element 81 has a hole in the middle so that the piezo element 81 is not preventing light entering the camera structure. However, the piezo element may also have another form than circular with a hole in the middle. The piezo element 81 may be attached with the protective sheet 82 with glue, tape or other adhesive material. The vibrating structure 80 may also comprise conductors 83 for providing appropriate electric signals to the piezo element 81 in order to produce vibrations in the piezo element 81. Such signals may be generated by an oscillator 84 controlled by a controller 85, or directly from the controller 85. It should be noted that there are many kinds of arrangements possible to implement controlling the piezo element 81 so that it vibrates at a desired frequency or frequency range. It should also be noted that the placement of the conductors 83 in Fig. 7a is only for illustrative purposes but in practical implementations the conductors 83 may be installed in a different way.

The piezo element 81 may also be called as a piezoelectric actuator or a piezo transducer.

Figs. 8a and 8b illustrate yet another embodiment of the apparatus 10. In this embodiment the incoming air is directed so that it begins to circulate around the outer surface 22a of the casing 22 of the camera 20 i.e. in the gap 30 delimited by the inner surface of the wall 17 and the outer surface 22a of the camera casing 22. The arrow 60 illustrates the flow of air in the gap and out from the apparatus 10. The circulation of air, which may also be called as vortex, may be caused by a wall 28 or another appropriate guiding element. This kind of circulating air flow may improve cleaning the front of the camera from dirt and also may even prevent particles entering the camera. Figs. 8a and 8b are greatly simplified illustrations of this embodiment and the arrow 60 exemplifying the air flow is just an example of this kind of circular, spiral air flow.

In accordance with an embodiment, the protective sheet 82 is not planar but may be at least partially curved. An example of such curved form is convex so that the distance from a central point of the protective sheet 82 to the frontmost lens 21 is greater than the distance from an edge of the protective sheet 82 to the frontmost lens 21 . The curved outer surface or the protective sheet 82 may even improve the flow of the compressed air in and out from the chamber 11 and thus possibly improve ejection of dirt particles out from the chamber 11 .

In accordance with an embodiment, a separate controller 85 may not be needed but the controller 50 of the apparatus may also be used for controlling the piezo element 81 .

The piezo element 81 need not be vibrating all the time but at certain moments, for example when the protective sheet 82 has become dirty or at intervals or when the camera 20 has been switched on, e.g. when a driver of a vehicle starts to backs up the vehicle and the reverse camera is needed to produce view to the back of the vehicle, etc.

In accordance with an embodiment, the waveform of the signals produced for the piezo element 81 may be pulse width modulated (PWM), a sine wave, a triangle wave etc. The frequency or frequency range may depend on the structure, material and/or dimensions of the protective sheet 82, such as a diameter and/or thickness. As an illustrative example, the frequency may be about 20 kHz, 50 kHz or even higher than that. When using the sweeping mode, the frequency range may be, for example, from about 19 kHz to about 21 kHz, or from about 48 kHz to about 52 kHz, but also other frequencies or frequency ranges may also be used depending on the protective sheet 82. These kind of relatively high frequency audio signals induced by the piezo element 81 may also be called as ultrasonic waves i.e. “sound” having frequency above 20 kHz.

In some embodiments the frequency generated for the piezo element 81 may sweep from a first frequency to a second frequency, and the sweeping frequency may be repeated a number of times. This may provide more freedom to the tolerances of the protective sheet 82 so that individual protective sheets 82 may have slightly different resonance frequencies within the frequency range. Thus, at least when the frequency of the signal provided to the piezo element corresponds with the resonance frequency (or a harmonic frequency of the resonance frequency) of the protective sheet 82, the protective sheet 82 begins vibrating and particles possible stuck on the surface of the protective sheet 82 may be expelled due to the vibrations. Hence, flow of air in the chamber 11 of the apparatus 10 blows such particles away from the chamber 11 and improves the visual properties of the camera arrangement.

In accordance with an embodiment, vibrations of the piezo element 81 may be used to warm the protective sheet 82 so that ice, which may have formed on the surface of the protective sheet 82, can be smelt away. The warming operation may also be used to dry possible moisture away from the surface of the protective sheet 82. The frequency in this warming operation may be different from the frequency used in the cleaning operation, but it can also be the same in both operations.

The apparatus 10 according to the invention can be applied with many vehicle cameras 20, such as a rear view camera, a side view camera, a front view camera, a camera of an autonomous driving system of a vehicle, etc.

Claims

Claims:

1. An apparatus (10) for a vehicle camera (20) having at least a frontmost lens (21 ) and an iris (23) in front of the frontmost lens (21 ), the apparatus comprising: an input (12) for receiving a flow of gas; a wall (17), which together with an outer surface (22) of the vehicle camera (20) forms a chamber (11 ) for directing the flow of gas to pass in front of the iris (23) of the vehicle camera (20); one or more channels (13) for leading the gas from the input (12) to the chamber (11 ); and an output orifice (15) associated with the chamber (11 ) for leading gas away from the iris (23) to atmosphere (40), wherein the chamber (11 ) is configured to lead the flow of gas to a front of the vehicle camera (20) and further away from the vehicle camera (20).

2. The apparatus (10) according to claim 1 comprising: an input pipe (14) for providing gas to the chamber (11 ).

3. The apparatus (10) according to claim 2 comprising: a compressor (18) for producing compressed air; and a pipe (19) coupled between the compressor (18) and the input pipe (14) for leading compressed air from the compressor (18) to the input (12).

4. The apparatus (10) according to claim 1 , 2 or 3 comprising: a wall (11 c) in the chamber (11 ) to divide the chamber (11 ) to at least a first section (11 a) and a second section (11 b).

5. The apparatus (10) according to any of the claims 1 to 4 comprising: a flange (16) in the chamber (11 ) to tighten the chamber (11 ) at the end opposite to the output orifice (15).

6. The apparatus (10) according to any of the claims 1 to 5 comprising: a heating arrangement (70) to warm at least a part of the apparatus (10).

7. The apparatus (10) according to any of the claims 1 to 6 comprising: a vibrating structure (80) to extract particles away from the chamber (11 ) of the apparatus (10).

8. The apparatus (10) according to claim 7, wherein the vibrating structure (80) comprises: a protective sheet (82) in front of the lens (21 ); and a piezo element (81 ) to induce vibrations on the protective sheet (82).

9. A method for preventing dirt entering a surface of at least a frontmost lens (21 ) of a vehicle camera (20) having an iris (23) in front of the frontmost lens (21 ), the method comprising: receiving a flow of gas by an input (12) of an apparatus (10); leading the flow of gas to a chamber (11 ) of the apparatus (10) formed by a wall (17) together with an outer surface (22) of the vehicle camera (20); directing the flow of gas by the chamber (11 ) to pass in front of the iris (23) of the vehicle camera (20); and leading the flow of gas away from the iris (23) to atmosphere (40).

10. The method according to claim 9, wherein the camera (20) has an iris (23) in front of a lens (21 ), the method comprising: directing the flow of gas by the chamber (11 ) to front of the iris (23).

11 . The method according to any of the claims 9 or 10 comprising: producing compressed air by a compressor (18); and leading compressed air from the compressor (18) to the chamber (11 ).

12. The method according to any of the claims 9 to 11 comprising: providing gas to at least a first section (11 a) and a second section (11 b) of the chamber (11 ).

13. The method according to claim 9 or 10 comprising: providing gas to the apparatus (10) based on movement of the vehicle camera (20).

14. The method according to any of the claims 9 to 13 comprising: using the output orifice (15) of the apparatus (10) as an iris (23) of the vehicle camera (20).

15. The method according to any of the claims 9 to 14 comprising: using a vibrating structure (80) to extract particles away from the chamber (11 ) of the apparatus (10).

16. A system comprising the apparatus (10) according to any of the claims 1 to 8 and the vehicle camera (20).

17. The system according to claim 16 further comprising a compressor (18) for producing compressed air for the apparatus (10).