DE102023102821A1 - Cleaning device and method for cleaning a surface - Google Patents

Abstract

The invention relates to a cleaning device for cleaning a surface by means of laser-induced single bubble cavitation, wherein the cleaning device has an inlet, an outlet, a chamber arranged fluidically between the inlet and the outlet, a laser device for emitting a laser beam and a light-conducting fiber for guiding the laser beam into the chamber. The invention further relates to an associated method.

Description

The invention relates to a cleaning device for cleaning a surface and a method for cleaning a surface.

Surfaces can be cleaned in different ways. Mechanical, chemical or combined methods are known for this. Particularly high demands are placed on the quality of cleaning when used in the semiconductor industry, for example, where surfaces of glass or semiconductor materials are cleaned.

It is an object of the invention to provide a cleaning device for cleaning a surface, which is designed alternatively or better than known designs. It is also an object of the invention to provide an associated method. This is achieved according to the invention by the subject matter of the main claims. Advantageous embodiments can be taken from the respective subclaims, for example. The content of the claims is made part of the content of the description by express reference.

The invention relates to a cleaning device for cleaning a surface by means of laser-induced single-bubble cavitation. The cleaning device has an inlet for a cleaning liquid. The cleaning device has an outlet for the cleaning liquid. The cleaning device has a chamber which is fluidically arranged between the inlet and the outlet. The cleaning device has a laser device which is designed to emit a laser beam. The cleaning device also has a light-conducting fiber with a first end and a second end. The first end is coupled to the laser device for receiving the laser beam. The light-conducting fiber extends into the chamber, in particular for emitting the laser beam and/or for laser-induced generation of single bubbles.

By means of such a cleaning device, it is advantageously possible to generate individual bubbles in the cleaning liquid, whereby the individual bubbles generate a cleaning effect on the surface. In particular, individual bubbles can collapse adjacent to the surface and thereby induce a liquid flow between the bubble and the surface. This liquid flow is essentially parallel to the surface and thus ensures that a mechanical cleaning effect is generated on the surface. This enables particularly good cleaning of the surface to be achieved. By using a light-conducting fiber that extends into the chamber, the laser beam can be guided very precisely in the cleaning liquid and the generation of individual bubbles can be controlled particularly precisely.

The inlet can be designed in particular as an inlet connection for supplying the cleaning liquid. The outlet can be used in particular for dispensing the cleaning liquid, in particular in the direction of an object to be cleaned. The cleaning liquid can in particular be supplied continuously at the inlet, so that the chamber is at least substantially always filled with cleaning liquid. The light-conducting fiber typically receives the laser beam at its first end and guides it to its second end. The laser beam exits at the second end and thus enters that area of the chamber or a volume occupied by the cleaning liquid which is not occupied by the fiber. If the chamber is filled with cleaning liquid, the laser beam thus enters this cleaning liquid. The cleaning liquid is typically of a type that absorbs the laser beam used and thus enables bubble generation. Individual bubbles are generated which can produce the cleaning effect already described. In particular, an aqueous liquid with surfactants, acids and/or bases can be used as the cleaning liquid.

According to one embodiment, the light-conducting fiber extends far enough into the chamber that the second end is still in the chamber. According to one embodiment, the light-conducting fiber extends far enough into the chamber that it protrudes from the outlet and the second end is thus outside the chamber.

In principle, several optical fibers can be used. The statements made here for the optical fiber apply to each of these.

The laser device is preferably designed as a continuous wave laser and/or modulated laser, particularly preferably as a modulated continuous wave laser. The use of a continuous wave laser has the advantage, in comparison to the use of pulsed lasers, that continuous wave lasers are significantly less complex and therefore also significantly cheaper. A continuous wave laser can be modulated in particular by only switching it on during certain periods of time and switching it off otherwise. This distinguishes a modulated continuous wave laser from a pulsed laser, which due to its internal physical structure can only individual pulses are generated. In principle, however, the use of a pulsed laser is also possible as an alternative.

According to an advantageous embodiment, the cleaning device has a tube, wherein the tube extends into the chamber and is preferably fluidically sealed to the chamber. In particular, an interior of the tube can be fluidically sealed to the chamber. The light-conducting fiber can in particular run partially in the tube and exit from the tube at an end of the tube located in the chamber. This can facilitate sealing at the fiber inlet into the nozzle structure or chamber and clamping at the nozzle exit or outlet. In particular, the tube can stabilize the fiber and/or position the second end of the fiber, wherein such positioning can be carried out by the tube closer to the outlet and is thus more precise than positioning the fiber without the tube. In addition, the fiber can be protected and/or mechanically stabilized.

In particular, it can be provided that the chamber is part of a head which can be freely positioned, at least to a limited extent, relative to the laser device and/or other components of the cleaning device, in particular a pump described below. This enables different cleaning positions to be easily approached.

In particular, the second end of the optical fiber can be arranged such that, in typical use or during use, a contactless distance of the second end of the optical fiber to a surface to be cleaned corresponds to a maximum of five times the bubble diameter. This is a value which enables the generation of a single bubble at a particularly advantageous distance from the surface, this single bubble producing an advantageous cleaning effect.

The cleaning device can in particular have a control device which can in particular be configured to control the laser device in such a way that the laser beam is only emitted in respective emission periods between which there are pause periods. No laser beam is therefore emitted during the pause periods. The emission periods are advantageously long enough for the water to boil with boiling delay taken into account. This is a function of the absorbed laser power and the fiber diameter. The emission periods can advantageously be at least 5 µs or at least 10 µs long. They can advantageously be at most 1 ms or at most 5 ms long. The pause periods can advantageously be at least 10 µs, at least 25 µs, at least 5 ms or at least 10 ms long. Such values have proven to be advantageous for typical applications. In principle, however, other values are also possible. Such values can be achieved, for example, with the modulatable continuous wave laser already mentioned above. The pulse lengths are typically longer than with pulsed lasers, and it has been found that, in particular, when using the fiber disclosed here, which enables particularly good control of the light beam, the use of an expensive pulsed laser can be dispensed with. The time periods mentioned can also be used in particular for the method described here.

The laser device can in particular emit a wavelength of at least 1.5 µm and/or of at most 2.5 µm. This corresponds to a wavelength in the infrared range, which enables advantageous generation of individual bubbles when using typical cleaning fluids. The instantaneous power density of the laser device at the second end of the fiber can in particular be at least 50 MW/m ² . In principle, other values can also be used.

In particular, the second end of the optical fiber can be flat and/or planar and/or level. This can mean in particular that an end face at the second end lies entirely or partially, for example at least 50% or at least 90% of the surface, in a plane which can in particular be aligned transversely to the longitudinal direction of the fiber or can assume an angle of at most 1°, at most 2°, at most 5°, at most 10°, at most 20° or at most 45° to the longitudinal direction of the fiber. In particular, it can be provided that the second end of the optical fiber is designed without refractive and/or focusing elements. In particular, it can be provided that the optical fiber does not focus the laser beam. In particular, it can be provided that the optical fiber is designed for collimated or divergent emission of the laser beam, in particular for emission into the cleaning fluid. A divergent emission can, for example, mean emission with an opening angle (in particular numerical aperture) of the laser beam of at most 15°. This means that focusing is not necessary. Not focusing avoids high power densities at a focus that would otherwise be required. In particular, it can be provided that there is no other element that focuses the laser beam.

The chamber can in particular be designed as a nozzle. This can taper in particular in the direction of flow from the inlet to the outlet. This can accelerate the cleaning fluid flowing through the chamber.

The cleaning device can in particular have a pump for supplying cleaning liquid to the inlet. This enables the reliable maintenance of a continuous volume flow of cleaning liquid which enters the chamber and exits through its outlet.

The outlet can in particular be designed as an opening lying in a plane. This enables advantageous adaptation to a surface, which is typically also flat. The outlet can in particular be designed as a round, oval or elliptical opening. This allows a suitable flow profile to be set at the outlet. However, other designs are also possible here.

In particular, the light-conducting fiber can be designed as a glass fiber. Such a glass fiber has advantageous light-conducting properties and guides the light from the laser device to the second end and then further into the cleaning fluid. However, other materials such as plastic can also be used.

• - Positionieren einer Reinigungsvorrichtung wie hierin beschrieben derart, dass deren Auslass auf die Oberfläche gerichtet ist,
• - Einleiten von Reinigungsflüssigkeit in den Einlass, und
• - Aktivieren der Laservorrichtung, dabei zweckmäßig Erzeugen einer oder mehrerer Blasen in der Reinigungsflüssigkeit am zweiten Ende der lichtleitenden Faser mittels des Laserstrahls.

The invention further relates to a method for cleaning a surface by means of laser-induced single bubble cavitation. The method comprises the following steps:

• - positioning a cleaning device as described herein such that its outlet is directed towards the surface,
• - Introducing cleaning fluid into the inlet, and
• - Activating the laser device, thereby expediently generating one or more bubbles in the cleaning liquid at the second end of the optical fiber by means of the laser beam.

The cleaning device already described can be used advantageously by means of such a method. In particular, it can be used to clean a surface by means of laser-induced single bubble cavitation. The cleaning fluid used is in particular such that it absorbs the wavelength used. This allows individual bubbles to be generated advantageously. With regard to the cleaning device, all of the designs and variants described can be used. The statements made with regard to the device apply accordingly to the method.

Generation at the second end can also be understood as generation near the second end.

Cleaning fluid emerging from the outlet can flow in particular in such a way that it directly hits the surface. The cleaning device can be arranged and aligned in the room accordingly. The introduction of cleaning fluid into the inlet can be continuous. Activating the laser device can lead in particular to the emission patterns of a laser beam described above. In particular, the durations for pulses and pauses mentioned above can be used.

A radius of the one or more bubbles generated can in particular be at least 50 µm or at least 100 µm. In particular, the radius of the one or more bubbles generated can be at most 2,000 µm or at most 3,000 µm. In particular, a radius of the one or more bubbles generated can correspond to at least one radius of the optical fiber. In particular, a radius of the one or more bubbles generated can be at most five or ten times as large as a radius of the optical fiber. The bubbles can take on ellipsoidal shapes, or elliptical in projection, in which the longer axis is, for example, parallel to the direction of the fiber. Such values have proven to be advantageous for typical cleaning applications. However, in principle other values can also be used. The values apply per bubble. In particular, operating parameters such as laser power, wavelength, pulse durations, cleaning fluid and/or flow rate of the cleaning fluid can be set so that such bubble sizes are achieved.

In particular, the second end of the light-conducting fiber can be positioned at a distance from the surface of at most three times or five times the maximum diameter of bubbles generated. This has proven to be advantageous for typical applications. In particular, a flow velocity of the cleaning liquid at the outlet can be at least 0.5 m/s or at least 1 m/s or at least 4 m/s. It has been shown that in at least some embodiments, the shape of a bubble is then suitably influenced by the flow.

The cleaning device and the method described herein can be used in particular for surface cleaning. For example, wafers in the chip industry, components in medical technology or High-precision mechanics can be cleaned. For example, oily production residues on components of precision scales can be removed. It is also possible to pre-treat bonding areas.

In other words, wet cleaning of surfaces is widely used in industrial and scientific processes. This includes, for example, the cleaning of medical equipment, parts that carry process media in industrial process engineering and the food industry, as well as the repeated cleaning of semiconductor wafers during the production process. Cleaning is carried out, for example, by combining chemical and physical processes. Chemical processes are based in particular on etching the surface contamination and reducing the adhesion forces. However, chemical processes have three major disadvantages. These include the sometimes high procurement and consumption costs and the potentially problematic disposal of the chemicals as well as potential damage to the surfaces. Physical processes can overcome these difficulties. They act on the adhering contamination via forces that must overcome the adhesion forces. In the area of wet cleaning of small contamination particles, these are usually shear forces. However, mechanical processes should also typically take place in a certain process window in which the forces are sufficient to remove the contamination without damaging the surface of the object being cleaned. In general, mechanical cleaning is more difficult the smaller the contamination particles are. This is particularly due to the relatively large influence of the surface forces responsible for particle adhesion and the difficulty of achieving sufficient (shear) forces close enough to the surface for small particles located in the hydrodynamic boundary layer. However, common physical processes do not allow precise control over the forces acting on the surface. In addition to tangential forces, which can also be referred to as shear forces, the processes typically also involve forces perpendicular to the surface. Ultrasonic cleaning, for example, works via microcurrents through acoustically generated cavitation bubbles. In ultrasonic baths, however, these appear in the form of cavitation bubble clouds in which the individual bubbles exhibit chaotic behavior and thus have hardly controllable properties. Such bubbles can, under certain circumstances, cause cavitation erosion even on very hard materials. In contrast, it is possible, for example, to obtain precise control over the forces on the surface using the mechanisms of physical wet cleaning processes described here. The forces are mediated via transient microcurrents generated by the collapse of the individual bubbles. Control and adjustability of the forces are essentially determined by three parameters over a certain range, namely bubble size, normalized bubble-wall distance and velocity of a background flow. In particular, the background flow is adjustable to influence the bubble dynamics.

In particular, a bubble can be generated by a continuous wave infrared laser. The laser output power can be modulated, for example, in the range 0 to 100% in the range of 100 Hz or several 100 Hz or in the kilohertz range and allows the generation of a thermocavity bubble of configurable size by adjusting the temporal modulation pattern. The bubble first oscillates and then collapses. The maximum achievable bubble radius can be used to describe the bubble size. This is, for example, in the range 100 µm to 2,000 µm or 3,000 µm. A bubble is generated in particular at the output tip of a glass fiber of suitable diameter. Such a structure achieves portability, low maintenance and robustness. The use of a wavelength with high absorption in the cleaning medium allows the use of lower power densities in contrast to plasma-induced bubble generation, for example with nanosecond pulsed lasers in the visible or very near infrared range. For the important application of water as a cleaning medium, a laser in a wavelength range of 2 µm may be suitable. The absorption coefficient of water is approximately 10 ⁵ cm ^-1 . Optical decoupling can, for example, prevent damage from back reflections on optics. The use of a glass fiber allows flexible movement of the cleaning head. The glass fiber is located axially in a nozzle with a round cross-section, for example, which generates a background flow with an adjustable volume flow. The cleaning medium, for example water, flows out of the nozzle. The resulting stagnation point flow allows control over tailor-made bubble dynamics in which, for example, gravitational forces can be increased, while at the same time, in contrast to bubble dynamics without background flow, the potentially erosive bubble collapse takes place at a certain distance from the surface, thus substantially reducing or completely eliminating the probability of erosion. The adjustable volume flow results in an average flow velocity at the nozzle outlet. The technically relevant range of the average flow velocity at the nozzle is, for example, in the range from 0 to 20 m/s. Such values can be used, for example, in the context of the method described here. Con Constant flow conditions can be achieved, for example, by actively controlling the pumping rate using a flow sensor and flow rectification using a honeycomb grid on the nozzle. The second crucial parameter for controlling bubble dynamics is the distance from the location of bubble generation, typically the second end of the fiber, to the item to be cleaned, normalized to the bubble radius. This can be achieved by precisely moving a cleaning head to the surface. The accuracy here is around 5 to 10% of the maximum radius. The relevant distance of an opening or a second end of the light-conducting fiber is, for example, 0 to 3 times or 0 to 5 times the maximum radius of the bubble and is adjustable. The nozzle can, for example, have a diameter of approximately one to ten times the maximum radius of a bubble.

When reference is made herein to bubble radii or bubble diameters, it should be noted that in typical implementations there is a totality of bubbles, in which there are typically also bubbles that are larger or smaller than specified. The information contained herein can then be understood to mean that at least half, at least three quarters, at least 90% or at least 95% of the energy of the laser beam emerging from the optical fiber, if used to generate bubbles, is used to generate bubbles that have the specified property.

If reference is made to the radius or diameter of the light-conducting fiber, in the case of designs of light-conducting fibers which have a core with a sheath, the core of the light-conducting fiber which guides the laser light and at whose radially outer boundary the laser light is reflected is to be considered in particular. The sheath is typically made of a material with a higher refractive index.

Moving the cleaning head relative to the object to be cleaned, particularly in a lateral direction, allows entire surfaces to be scanned at high bubble generation frequencies. Several glass fibers can be combined in a cleaning head at a sufficient distance, for example around five maximum bubble radii, to achieve the higher surface cleaning rate. For this purpose, the nozzle can be widened or divided accordingly. Automatic distance detection and control can be integrated into a cleaning head, which adjusts the distances if necessary, particularly if the surface is moved laterally relative to the cleaning head.

By dispensing with focusing, it is possible in particular to create a bubble at the output tip, for example at the second end, of an optical fiber. This allows more precise control over the location of the bubble generation and prevents the laser beam from passing through the cleaning fluid over a longer area to the focus. This can in particular prevent a laser beam spreading out over a longer period in the cleaning fluid from forming a tunnel-shaped channel of evaporated cleaning fluid and thus, due to a lack of attenuation, reaching the surface to be cleaned directly, which could then be damaged.

The cleaning device described here can basically be used in any orientation. The bubble generation is controlled in such a way that the orientation is determined by the flow of the cleaning liquid, which is independent of the orientation of the cleaning device relative to gravity.

• 1: eine Reinigungsvorrichtung.

The person skilled in the art will find further features and advantages in the embodiment described below with reference to the attached drawing.

• 1 : a cleaning device.

1 shows a cleaning device 10 according to an embodiment of the invention. The cleaning device 10 serves to clean a surface 16 of an object 15. The object 15 is a pane of glass in the present case, although other objects 15 can also be cleaned. On the surface 16 there are dirt particles 17 which are to be removed by means of the cleaning described here.

The cleaning device 10 has a chamber 20. The chamber 20 has an inlet 22 through which cleaning liquid 12 can be supplied. The chamber 20 also has an outlet 24 through which the cleaning liquid exits. In between there is a flow straightener 26 through which the cleaning liquid 12 in the chamber 20 is made uniform in terms of its flow. The flow straightener 26 can, for example, have a honeycomb structure.

A supply line 30 is provided for supplying cleaning liquid 12. This is connected to the inlet 22. A pump 32 pumps the cleaning liquid 12 in the direction of the inlet 22. A flow sensor 34 measures the flow.

The cleaning device 10 has a laser device 40 for generating a laser beam. This is coupled to a coupling device 42, which serves to deliver the laser beam to a light-conducting fiber described below. A control device 44 is used for control.

The cleaning device 10 has a light-conducting fiber 50. The light-conducting fiber 50 has a first end 51 and a second end 52. The first end 51 is connected to the coupling device 42 as shown in order to ultimately couple the first end 51 to the laser device 40. The light-conducting fiber 50 then runs into a tube 28 which is hollow on the inside and extends into the chamber 20. The majority of the light-conducting fiber 50 is thus shielded from the cleaning liquid 12. At the 1 On the side of the tube 28 shown on the right, the light-conducting fiber 50 protrudes beyond the tube 28 and thus enters the chamber 20 outside the tube 28. The second end 52 is thus located in the cleaning liquid 12. An emerging laser beam, which is generated by the laser device 40 and guided via the light-conducting fiber 50 to its second end 52, thus exits from the second end 52 and into the cleaning liquid 12. There it is possible to generate a single bubble 14 which is at a defined distance from the surface 16.

The chamber 20 forms a head 11, which can be positioned independently of other components, in particular the laser device 40 and the pump 32, at least within predetermined limits. For this purpose, the light-conducting fiber 50 and the feed line 30 are designed to be flexible. This enables the head 11 to be moved to different positions without having to move the other components.

The laser device 40 is a modulated continuous wave laser. This can generate pulse widths of several hundred microseconds with pauses of several hundred microseconds in between. While a respective pulse is active, a single bubble 14 is generated, which then detaches and is moved towards the surface 16 due to the flow of the cleaning liquid 12 through the chamber 20. The forces acting on the single bubble 14 due to the flow of the cleaning liquid 12 are considerably greater than the force of gravity, which would move the single bubble 14 vertically upwards. The cleaning device 10 can therefore be used in any orientation and functions independently of the influence of gravity.

By using the light-conducting fiber 50, it is possible in particular to achieve free positioning of the chamber 20 relative to the laser device 40. For this purpose, the light-conducting fiber 50 can be designed to be at least partially or completely flexible. This makes a cleaning process much easier, since the laser device 40 can be placed stationary and only the chamber 20 is positioned flexibly.

As in 1 As can be seen, the second end 52 of the light-conducting fiber 50 has no curvature. Rather, it forms a smooth end of the light-conducting fiber 50, which thus has a flat end surface in a plane transverse to the longitudinal extent of the light-conducting fiber 50. This prevents focusing of the emerging laser beam. The single bubble 14 is thus created directly adjacent to the second end 52. By omitting focusing, damage to the surface 16 is avoided, which would otherwise be possible due to possible tunnel formation within the cleaning liquid 12. If tunneling occurs, the cleaning liquid 12 evaporates along a tunnel, which would thus enable the laser beam to reach the surface 16 without being absorbed by the cleaning liquid 12. The high energy then occurring at the surface 16 can damage the surface 16.

In 1 Two distances are shown, namely a distance s between the outlet 24 and the surface 16, and a distance d between the individual bubble 14 and the surface 16. The distance d can be measured in particular from the center of the individual bubble 14. To simplify this, the distance of the second end 52 to the surface 16 can also be used. The distance d is preferably a maximum of about three times the diameter of the individual bubble 14. The distance s is typically somewhat larger and is a maximum of about five times the diameter of the individual bubble 14. Suitable operating parameters can thus be set, which have proven to be advantageous for typical applications.

Mentioned steps of the method according to the invention can be carried out in the order given. However, they can also be carried out in a different order, as long as this is technically reasonable. The method according to the invention can be carried out in one of its embodiments, for example with a certain combination of steps, in such a way that no further steps are carried out. However, in principle, further steps can also be carried out, including those which are not mentioned.

It should be noted that in the claims and in the description features in combination, for example to facilitate understanding, although they can also be used separately. The person skilled in the art will recognize that such features can also be combined independently of one another with other features or combinations of features.

References in subclaims may indicate preferred combinations of the respective features, but do not exclude other combinations of features.

List of reference symbols

10

Cleaning device

11

Head

12

Cleaning fluid

14

Single bubble

15

object

16

surface

17

Dirt particles

20

chamber

22

inlet

24

Outlet

26

Flow straightener

28

Pipe

30

Supply line

32

pump

34

Flow sensor

40

Laser device

42

Coupling device

44

Control device

50

optical fiber

51

first end

52

second end

d

Distance between individual bubble and surface

s

Distance between outlet and surface

Claims (15)

Cleaning device (10) for cleaning a surface (16) by means of laser-induced single-bubble cavitation, the cleaning device (10) having the following: - an inlet (22) for a cleaning liquid (12), - an outlet (24) for the cleaning liquid (12), - a chamber (20) which is fluidically arranged between the inlet (22) and the outlet (24), - a laser device (40) which is designed to emit a laser beam, and - a light-conducting fiber (50) with a first end (51) and a second end (52), the first end (51) being coupled to the laser device (40) for receiving the laser beam and the light-conducting fiber (50) extending into the chamber (20) for emitting the laser beam and for the laser-induced generation of single bubbles (14). Cleaning device (10) according to Claim 1 , - wherein the laser device (40) is designed as a modulatable continuous wave laser. Cleaning device (10) according to one of the preceding claims, - which has a tube (28), - wherein the tube (28) extends into the chamber (20), - wherein the light-conducting fiber (50) runs partially in the tube (28) and exits the tube (28) at an end of the tube (28) located in the chamber (20). Cleaning device (10) according to one of the preceding claims, - wherein the chamber (20) is part of a head (11) which can be freely positioned at least to a limited extent relative to the laser device (40) and/or other components of the cleaning device (10). Cleaning device (10) according to one of the preceding claims, - which has a control device (44) which is configured to control the laser device (40) such that the laser beam is only emitted in respective emission periods between which there are pause periods. Cleaning device (10) according to Claim 5 , - wherein the delivery periods are at least 5 µs or at least 10 µs long, and/or - wherein the delivery periods are at most 1 ms or at most 5 ms long, and/or - wherein the pause periods are at least 10 µs or at least 25 µs long, and/or - wherein the pause periods are at least 5 ms or at least 10 ms long. Cleaning device (10) according to one of the preceding claims, - wherein the laser device (40) emits a wavelength of at least 1.5 µm and/or of at most 2.5 µm, and/or - wherein an instantaneous power density of the laser device (40) at the second end (52) of the optical fiber (50) is at least 50 MW/m ² . Cleaning device (10) according to one of the preceding claims, - wherein the second end (52) of the optical fiber (50) is flat, and/or - wherein the optical fiber (50) does not focus the laser beam, and/or - wherein the optical fiber (50) is designed for collimated or divergent emission of the laser beam. Cleaning device (10) according to one of the preceding claims, - wherein the chamber (20) is designed as a nozzle which tapers in the flow direction from the inlet (22) to the outlet (24). Cleaning device (10) according to one of the preceding claims, - which has a pump (32) for supplying cleaning liquid (12) to the inlet (22). Cleaning device (10) according to one of the preceding claims, - wherein the outlet (24) is designed as an opening lying in a plane, and/or - wherein the outlet (24) is designed as a round, oval, elliptical or square opening. Cleaning device (10) according to one of the preceding claims, - wherein the light-conducting fiber (50) is designed as a glass fiber. Method for cleaning a surface (16) by means of laser-induced single bubble cavitation, the method comprising the following steps: - positioning a cleaning device (10) according to one of the preceding claims such that its outlet (24) is directed towards the surface (16), - introducing cleaning liquid (12) into the inlet (22), and - activating the laser device (40), thereby generating one or more single bubbles in the cleaning liquid (12) at the second end (52) of the light-conducting fiber (50) by means of the laser beam. Procedure according to Claim 13 , - wherein a radius of the one or more bubbles generated is at least 50 µm or at least 100 µm, and/or - wherein a radius of the one or more bubbles generated is at most 2,000 µm or at most 3,000 µm, and/or - wherein a radius of the one or more bubbles generated corresponds to at least a radius of the light-conducting fiber (50), and/or - wherein a radius of the one or more bubbles generated is at most five times or ten times as large as a radius of the light-conducting fiber (50). Method according to one of the Claims 13 or 14 , - wherein the second end (52) of the optical fiber is positioned at a distance from the surface (16) of at most three times or five times the maximum diameter of bubbles generated.

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