BE1030227A1 - Laser device, method and computer program - Google Patents

Abstract

Laser device comprising a laser scanning head for directing the laser beam at the object, a transport unit for moving the object and the laser scanning head relative to each other, and a control unit configured to control the laser scanning head to perform a first scanning movement of the laser beam and a second scanning movement of the laser beam. The control unit is configured to control the transport unit to move the object and the laser scan head relative to each other in a transport direction during the first scanning movement and during the second scanning movement. The laser scan head is configured to perform the first scan move by moving the laser beam along a first scan direction to irradiate a first line on the object. The laser scan head is configured to perform the second scanning move by moving the laser beam along a second scanning direction to irradiate a second line on the object. The first scanning direction extends over at least part of a width of the object. The width is in a direction perpendicular to the direction of transport. The second scanning direction extends over at least part of the width of the object opposite to the first scanning direction. The controller is configured to control the second scan direction based on the first scan direction and a vector in the transport direction.

Description

2023/5055 1

BE2023/5055

Laser device, method and computer program

The invention relates to a laser device, in particular a cleaning laser device. The invention further relates to a method for irradiating an object with a laser beam, and to a computer program with instructions to be executed by a control unit of a laser device. The invention further relates to a laser scanning head and to a control unit for use in a laser device.

For the laser cleaning of an object, a laser device is provided that irradiates the object with a laser beam. By irradiating the object, the laser beam irradiates contamination on the object, such as particles, rust or coatings that need to be removed.

The energy of the laser beam causes a reaction of the contamination on the surface of the object. The reaction allows the contamination to evaporate or sublimate. The reaction can cause a chemical reaction, such as oxidation of the contamination. The energy of the laser beam per unit area must be high enough to cause the desired reaction of the contamination. However, the energy of the laser beam per unit area must be low enough to prevent damage to the object.

When cleaning an object with a laser cleaning device, it is important that the laser beam of the laser cleaning device irradiates the object as uniformly as possible.

By irradiating the object evenly over the entire object, the desired reaction of the contamination is obtained, while damage to the object is prevented. If the object is not irradiated evenly, contamination may remain in some areas of the object due to a lack of sufficient radiation, while some other parts of the object may be damaged by an excessive amount of radiation.

However, the laser device should not only obtain a desired cleanliness of the object, but the laser device should also irradiate a sufficient surface of the object per unit of time. The more surface area the laser device irradiates per unit of time, the higher the cleaning power of the laser device.

To improve the cleaning capacity, the object typically moves relative to the laser device in a transport direction. The known laser device scans the laser beam back and forth over the width of the object. During each scan over the object, a line is irradiated over the object.

As the laser beam is scanned over the object, the object moves relative to the laser beam in the transport direction. As a result, the laser beam irradiates a pattern of

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BE2023/5055 zigzag lines on the object. Due to the zigzag pattern, some parts of the object receive less radiation from the laser beam than other parts. As a result, the transport speed is set to a low value, so that the object is properly cleaned in the places that receive the least radiation. As a result, the cleaning power of the known laser device is low.

In a known laser device disclosed in the PCT patent application

WO2010/086865 the object to be cleaned is placed at an angle to the direction of transport. When scanning the laser beam perpendicular to the transport direction, the transport speed causes the laser beam to describe a line along the object that corresponds to the angle to the transport direction. For example, parallel lines are beamed onto the object instead of a pattern of zigzag lines.

However, during a scan, the laser beam moves from one side of the object to the other. At the end of the scan, the laser beam is returned to the starting side of the object to start the next scan. As a result, the known laser device has a limited cleaning power.

It is an object of the invention to provide an improved laser device, or at least to provide an alternative laser device. Optionally, the improved laser device is capable of irradiating a larger area per unit time and/or irradiating a surface with a more uniform irradiation over the surface than the known laser device.

The object of the invention is achieved by a laser device for irradiating an object with a laser beam. The laser device includes a laser scanning head for directing the laser beam at the object, a transport unit for moving the object and the laser scanning head relative to each other, and a control unit configured to control the laser scanning head to perform a first scanning movement of the laser beam and a second scanning movement of the laser beam. The control unit is configured to control the transport unit to move the object and the laser scan head relative to each other in a transport direction during the first scanning movement and during the second scanning movement. The laser scan head is configured to perform the first scan move by moving the laser beam along a first scan direction to irradiate a first line on the object. The laser scan head is configured to perform the second scanning move by moving the laser beam along a second scanning direction to irradiate a second line on the object. The first scanning direction extends over at least part of a width of the object. The width is in a direction perpendicular to the direction of transport. The second scanning direction extends over at least part of the width of the object

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BE2023/5055 opposite to the first scanning direction. The controller is configured to control the second scan direction based on the first scan direction and a vector in the transport direction.

Due to the first scanning movement of the laser beam, the laser scanning head irradiates the first line on the object. During the first scanning movement, the laser beam moves along the first scanning direction. Depending on the first scanning direction, the first line has a certain orientation on the object. For example, the first line is applied to the object perpendicular to the direction of transport, or at an oblique angle to the direction of transport.

During the second scanning movement of the laser beam, the laser scan irradiates the second line on the object. During the second scanning movement, the laser beam moves along the second scanning direction. While during the first scanning movement the laser beam moves over at least part of the width of the object in one direction, during the second scan the laser beam moves over at least part of the width of the object in the opposite direction.

So by moving the laser beam with the first scan move and the second scan move, the laser beam moves back and forth across the width of the object.

With the known laser device, moving the laser beam back and forth across the width of the object would result in a pattern of zigzag lines on the object, because the known laser device moves the laser beam back and forth over the same scanning direction. However, the laser device according to the invention includes the controller configured to control the second scanning direction based on the first scanning direction and a vector in the transport direction. The control unit controls the second scanning direction by taking the first scanning direction as a basis and correcting this basis with the vector in the transport direction. By correcting this basis with the vector in the transport direction, the second scanning direction is not parallel to the first scanning direction. As a result, the second scanning direction takes into account the movement of the laser scanning head relative to the object during the second scanning movement. This allows the laser scan head to irradiate the second line more accurately relative to the first line to achieve more uniform irradiation of the object.

The laser device is, for example, a cleaning laser device for cleaning the object. The cleaning laser is adapted to remove unwanted particles or coatings from the object. For example, the laser device is adapted to perform a surface treatment of the object, such as laser polishing. For example, the laser device is adapted to perform laser beam processing to create features in the object by removing material from the object. For example, the laser device is configured to emit a pulsed laser beam with an energy between 1-100 mJ and a frequency between 1 kHz - 1 MHz. For example, the laser device should operate like a Class 1 laser, which is below all normal

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BE2023/5055 conditions of use is safe. For example, the laser device comprises a laser source for generating the laser beam. In another example, the laser device is adapted to be coupled to a laser source for generating the laser beam. For example, the laser device includes a coupler for an optical guide, such as an optical fiber or an optical waveguide, to receive the laser beam from the laser source.

The object is any object that can be irradiated with the laser beam. For example, the object is made of metal or ceramic. For example, the object has a surface with corrosion that must be removed by the laser beam. For example, the object is part of a battery. For example, the object has a flat surface to receive the laser beam, and/or a curved surface to receive the laser beam. For example, the surface of the object to be irradiated with the laser has openings, such as through holes or recesses.

The laser scanning head directs the laser beam from the laser source onto the object. For example, the laser scanning head has one or more movable mirrors to receive the laser beam from the laser source and direct the laser beam at the object. For example, the laser scanning head is adapted to move at least one of the movable mirrors to move the laser beam in a scanning motion. For example, the laser scan head has one or more optical components to adjust a property of the laser beam, such as a cross section of the laser beam or a focus point.

The transport unit is intended to move the object and the laser scan head relative to each other. The transport unit is adapted to move the object relative to a stationary laser scan head, to move the laser scan head relative to a stationary object, or to move both the object and the laser scan head. The transport unit includes, for example, a platform system or a transport system for supporting the object. By operating the platform system or the transport system, the object is moved relative to the laser scan head. For example, the transport unit includes a lathe to rotate the object relative to the laser scanning head. For example, the transport unit includes a platform system or a gantry to support the laser scan head. By operating the platform system or the gantry system, the laser scan head is moved relative to the object.

The control unit is configured to control the laser scan head. For example, the control unit is connected to the laser scan head to provide a control signal to the laser scan head. Based on the control signal, the laser scan head moves one or more movable mirrors to focus the laser beam on the object and perform a scanning movement.

The control unit is configured to control the transport unit to move the object and the laser scan head relative to each other in a transport direction. The

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For example, BE2023/5055 control unit is connected to the transport unit to provide a transport control signal to the transport unit. Based on the transport control signal, the transport unit moves the object relative to the laser scan head.

For example, the control unit controls the transport unit to move the object and the laser scan head relative to each other at a constant speed. For example, the transport unit includes a motor adapted to move in response to the transport control signal.

For example, the control unit includes a processor for executing software, and a memory for storing the software. For example, the software includes instructions representing the directions of the first scan direction and the second scan direction. For example, the instructions are the result of off-line calculations where the second scan direction is calculated based on the first scan direction and the vector. The control unit comprises, for example, a Programmable

Logic Controller (PLC) or a Field-Programmable Gate Array (FPGA). The control unit includes, for example, an interface. Through the interface, an operator can communicate with the control unit to operate the laser device. The interface comprises, for example, a touch screen or a keyboard or a communication device. For example, the communication device is adapted for wired communication or for wireless communication, such as

bluetooth. For example, the interface contains a connector for connecting to a data carrier, such as a USB stick, an SD card, a CD-R or a DVD-R. For example, the control unit is implemented as a single unit or multiple units. For example, the part of the control unit configured to control the laser scan head is implemented in a different unit than the part of the control unit configured to control the transport unit.

The controller is configured to control the laser scan head to perform the first scan move and the second scan move as the transport unit moves the object relative to the laser scan head. So when the object is irradiated during the first scan move and the second scan move, the object moves relative to the laser scan head.

During the first scanning movement, the laser scanning head moves the laser beam in the first scanning direction. The laser beams orbit with respect to the laser scan head along the first scanning direction. The first scanning direction extends over at least part of the width of the object. The first scanning direction is in a direction parallel to the width direction, or the first scanning direction is in a direction that has a component in the width direction and a component in the transport direction. During the first scanning movement, the laser beam moves across the entire width of the object, i.e. starting on one side of the object and stopping on the other side of the object, or the

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BE2023/5055 laser beam moves over part of the width of the object. For example, the first line starts at a distance from the nearest edge of the object and/or the first line ends at a distance from the nearest edge of the object. In some applications it is not necessary or desirable to irradiate the entire object, so it is sufficient to move the laser beam over only part of the width of the object.

The second scanning direction extends over at least part of the width of the object opposite to the first scanning direction. For example, the first scanning direction is from left to right across the width of the object. Then the second scanning direction is from right to left across the width of the object. The second scanning direction is in a direction parallel to the width direction, or the second scanning direction is in a direction having a component in the width direction and a component in the transport direction. During the second scan move, the laser beam moves across the entire width of the object, i.e. starting on one side of the object and stopping on the other side of the object, or the laser beam moves part of the width of the object. Preferably, the laser beams move equally in the direction of the width of the object during the first scanning movement and the second scanning movement.

During the first scanning movement, the laser beam moves along the first scanning direction and irradiates the first line on the object. The length of the first line is determined by the distance the laser beam travels during the first scanning pass. The width of the first line is determined by a width of the laser beam, for example the diameter of the laser beam. The width of the laser beam is perpendicular to the first scanning direction. The first and second line are called lines because the length of such a line is typically a few mm's or more, while the width of the line is typically about 50-200 µm. So the lengths of the first line and the second are significantly greater than their widths. During the first scanning movement, the laser beam forms an irradiated area on the object along the first line.

The irradiated area is formed, for example, by several laser pulses. For example, the laser pulses are next to each other without overlapping or overlapping. The degree of overlap is, for example, 5% or 10% or 20% of the diameter of the laser beam. For example, the degree of overlap differs along the first line. The first line is a straight line or a curved line.

During the second scanning movement, the laser beam moves along the second scanning direction and irradiates the second line on the object. The length of the second line is determined by the distance the laser beam travels during the first scan. For example, the second line has the same length as the first line. The width of the second line is determined by the width of the laser beam, for example the diameter of the laser beam. The width of the laser beam is perpendicular to the second scanning direction. During the second scanning pass, the laser beam forms an irradiated area on the object along the second line.

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BE2023/5055

The irradiated area is formed, for example, by several laser pulses. For example, the laser pulses are next to each other without overlapping or overlapping. The degree of overlap is, for example, 5% or 10% or 20% of the diameter of the laser beam. For example, the degree of overlap differs along the second line. The second line is a straight line or a curved line. For example, the second line has the same shape as the first line. For example, the laser scan head irradiates the second line to partially overlap the first line. The degree of overlap is, for example, 5% or 10% or 20% of the diameter of the laser beam.

The controller is configured to control the second scan direction based on the first scan direction and a vector in the transport direction.

In a first example, the first scanning direction is perpendicular to the transport direction.

The first line starts at a first starting point and ends at a first ending point. Because the first scanning direction is perpendicular to the transport direction, the first line is applied to the object at an angle to the transport direction, with the first start point being the leading end and the first end point being the trailing end of the first line. The second scan move starts irradiating the second line near the first end point and stops irradiating the second line near the first start point. To arrange the second line parallel to the first line, the second scanning direction is determined by the first scanning direction and a vector in the transport direction. The vector in the direction of transport must be large enough to account for the skew angle of the first line and the transport speed.

In a second example, the first line is perpendicular to the direction of transport. Because the object moves in the transport direction during the first scan move, the first scan direction has a vector in the transport direction. The first line starts at the first starting point and ends at the first ending point. The second scan move starts irradiating the second line near the first end point and stops irradiating the second line near the first start point. To arrange the second line parallel to the first line, the second scan direction is determined by the first scan direction and the vector in the transport direction.

Because the second scan direction is partially opposite to the first scan direction, the vector at least partially compensates for the vector that was included in the first scan direction. In addition, the vector includes the transport speed.

In a third example, the second scanning direction is perpendicular to the transport direction.

To irradiate the first line and the second line parallel to each other, the first scanning direction would have a large component in the transport direction. Thus, when the controller controls the second scan direction based on the first scan direction and the vector, the vector takes into account the large component in the transport direction of the first scan direction.

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BE2023/5055

In one embodiment, the controller is configured to control the laser scan head to apply the first line and the second line parallel to each other on the object.

When creating a first line and a second line in a zigzag pattern with a known laser device, the laser beam would end at a distance from where the laser beam started. The distance is in the transport direction. The transport speed of the known laser device is limited to ensure that the distance is sufficiently small for good irradiation. According to the invention, the laser beam moves back and forth over the object with the first scanning movement and the second scanning movement. By arranging the first line and the second line parallel to each other, the laser beam ends at a distance from where the laser beam started with the first scanning movement, which is only half compared to that of the known laser device. The transport speed and the scanning speed of the laser beam are the same for both situations. The embodiment hereby enables a higher transport speed while still achieving good irradiation of the object. For example, the transport speed is increased by a factor of two.

In one embodiment, the controller is configured to control the laser scan head to juxtapose the first line and the second line.

According to this embodiment, the first line and the second line are applied next to each other on the object. For example, the first line and the second line are arranged next to each other without overlapping or overlapping each other. The degree of overlap is, for example, 5% or 10% or 20% of the diameter of the laser beam. By applying the first line and the second line next to each other on the object, an improved irradiation of the object is achieved.

In one embodiment, the vector in the transport direction is based on a scanning speed of the second scanning movement. The scan speed is a speed at which the laser scan head moves the laser beam along the second scanning direction to irradiate the second line.

According to this embodiment, the vector depends on the scanning speed. If the scanning speed is fast, the second scanning movement will be performed in a short amount of time. In this short amount of time, there is only a slight movement of the object relative to the laser scanning head. As a result, the vector in the transport direction is small. In case the scanning speed is low, the second scanning move is performed in a large amount of time. In this large amount of time, there is a large movement of the object relative to the laser scanning head. As a result, the vector in the transport direction is large. By taking into account the scanning speed of the second scanning movement, the control unit can determine the second scanning direction more accurately. For example, the scan speed of the second scan move is equal to the scan speed of the first

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BE2023/5055 scan movement. In another example, the scan speed of the second scan move differs from the scan speed of the first scan move.

In one embodiment, the control unit is configured to control the transport unit to move the object and the laser scan head relative to each other in the transport direction at a transport speed. The vector in the transport direction is based on the transport speed.

The transport speed determines how much the object moves relative to the laser scan head per unit time. At a low transport speed, the second scan direction is less affected by the vector in the transport direction. If the transport speed is high, the second scan direction is more affected by the vector in the transport direction. For example, the vector in the transport direction is based on the transport speed and the scan speed, for example a ratio between the transport speed and the scan speed.

In one embodiment, the controller is configured to control the second scan direction based on an inverse of the first scan direction.

According to this embodiment, the controller bases the second scan direction on an inverse of the first scan direction. The first scanning direction extends over part of the width of the object. By basing the second scan direction on the inverse of the first scan direction, the second scan direction extends at least part of the width opposite to the first scan direction. The controller bases the second scan direction on the inverse of the first scan direction and the vector in the transport direction to account for the movement of the object relative to the laser scan head.

IN one embodiment, the laser scan head includes at least one mirror and at least one galvo scanner motor. The at least one mirror is arranged to reflect the laser beam to the object. The at least one galvo scanner motor is configured to rotate the at least one mirror. The controller is configured to control the at least one galvo scanner motor to control the first scan move and the second scan move.

According to this embodiment, the laser scanning head has one or more mirrors. A galvo scanner motor is provided for each of the mirrors to rotate the mirrors. By rotating the mirrors, the mirrors reflect the laser beam to move according to the first scanning movement and the second scanning movement. For example, the galvo scanner engine has two mirrors, each with a galvo scanner engine. Each galvo scanner motor is arranged to rotate one of the mirrors. The two mirrors are arranged to reflect the laser beam and move the laser beam over a two-dimensional surface over the object. For example, the control unit is configured to control the motors of the galvo scanner to rotate the two mirrors.

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In one embodiment, the laser scan head is configured to start the first scan move at a first start point on the first line, to stop the first scan move at a first end point on the first line, to start the second scan move at a second start point on the second line, and to stop the second scan move at a second endpoint on the second line. The laser scan head is configured to apply the first end point and the second start point to the object at a distance from each other. The distance is in a direction perpendicular to the first line. The distance is equal to or less than a diameter of the laser beam.

According to this embodiment, the laser beam moves along the object from the first start point to the first end point during the first scanning movement. During the second scan move, the laser beam moves past the object from the second start point to the second end point. When the laser beam is at the second end point, the laser beam is at the distance from the first starting point. Because this distance is less than a diameter of the laser beam, there is no or only an acceptably small area between the first line and the second line that is not irradiated by the laser beam. As a result, the object is better irradiated by the laser beam. In case the distance is equal to the diameter of the laser beam, the irradiated areas of the first line and the second line adjoin each other without overlap. If the distance is smaller than the diameter of the laser beam, the irradiated areas of the first line and the second line partly overlap. In case the laser beam has a circular cross-section, the diameter is the diameter of the circular cross-section. In case the cross-section has the shape of a polygon, the diameter corresponds to the largest diagonal of the cross-section shape. In case the first line is curved, the distance is in a direction perpendicular to a tangent of the first line at the first end point.

In one embodiment, the distance is less than 80% of the diameter of the laser beam.

According to this embodiment, the irradiation of the object is improved by choosing a distance of less than 80% of the diameter of the laser beam. By choosing this distance, there is sufficient overlap between the irradiated area of the first line and the irradiated area of the second line to ensure good irradiation of the object.

In one example, the laser beam has a circular cross-section and is a pulsed laser beam. By choosing the distance less than 80% of the diameter of the laser beam, between pulses there will be no or very little area on the object that is not sufficiently irradiated by the laser beam.

In one embodiment, the laser scan head is configured to apply the laser beam at a first laser start position to irradiate the first start point, apply the laser beam at a first laser end position to irradiate the first end point,

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BE2023/5055 apply the laser beam in a second laser start position to irradiate the second start point, apply the laser beam in a second laser end position to irradiate the second end point. The first laser start position, the first laser end position, the second laser start position, and the second laser end position are relative to the laser scan head.

The laser beam in the second laser start position is arranged opposite to the direction of transport relative to the laser beam in the first end position.

According to this embodiment, the laser beam moves relative to the laser scan head from the first laser start position to the first laser end position during the first scanning movement. During the second scanning movement, the laser beam moves relative to the laser scanning head from the second laser start position to the second laser end position. The laser scan head starts the second scan move at the second laser start position relative to the first laser end position upstream in the transport direction. In this way, the laser scan head can make the first laser start position, the first laser end position, the second laser start position and the second laser end position closer to each other, which simplifies the mechanical design of the laser scan head. For example, the laser beam is interrupted between the first laser end position and the second laser start position.

In one embodiment, the second laser start position is equal to the first laser end position.

According to this embodiment, the laser scanning head ends the first line with the laser beam at the first laser end position, and starts the second line with the laser beam at the same laser position. The laser scan head waits with the laser beam in the first laser end position until the object has moved sufficiently in the transport direction before starting with the second line. This helps to simplify the control of the laser beam. In an example, the laser scan head returns the laser beam to the first laser start position after irradiating a certain number of lines, for example 10 lines or 50 lines or more than 100 lines.

In one embodiment, the laser beam in the second laser end position is arranged in the direction of transport relative to the laser beam in the first laser start position.

According to this embodiment, the laser beam moves relative to the laser scan head from the second laser start position to the second laser end position during the second scanning movement. In order to take into account the vector in the transport direction, the second laser end position is arranged in the transport direction with respect to the laser beam in the first laser start position.

In one embodiment, the laser scan head is configured to perform the first scanning pass to irradiate a third line on the object. The laser scan head is configured to start the third scan move at a third start point on the third line, stop the third scan move at a third end point on the third line, aim the laser beam at the first laser start position on the third start point, and aim the laser beam Unpleasant

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BE2023/5055 the first laser end position to irradiate the third end point. The first line and the third line are on opposite sides of the second line.

According to this embodiment, the laser scanning head can irradiate the third line in a similar manner to the first line. In this way, the laser scanning head can repeat the irradiation of lines to irradiate a desired surface of the object.

In one embodiment, the laser scan head is configured to irradiate the first line. The first line is perpendicular to the direction of transport.

According to this embodiment, the first line is at an angle of 90 degrees to the direction of transport. Irradiating the first line perpendicular to the direction of transport is especially advantageous if the first line has a relatively long length, for instance more than 30 mm or more than 40 mm or more than 100 mm. By applying the first line perpendicular to the direction of transport, the first line is as short as possible while still extending as much as possible over the width of the object. Since the length of the first line is relatively long, the laser scanning head can obtain a high scanning speed and/or a large average scanning speed.

The inertia of moving parts, such as rotating mirrors, in the laser scan head does not substantially affect the average scan speed. In this way, the laser scan head can achieve a maximum scanning speed, for example. The maximum scan speed is the maximum scan speed for which the laser scan head is designed.

In one embodiment, the laser scan head is configured to irradiate the first line. The first line has an oblique angle to the direction of transport.

According to this embodiment, the first line is at an angle other than 90 degrees to the direction of transport. The angle is between 0-90 degrees. Irradiating the first line at an angle to the direction of transport is particularly advantageous if the width of the object to be irradiated has a relatively short length, for example less than 50 mm or more less than 40 mm or less than 30 mm. By applying the first line at an angle to the direction of transport, the first line can be made longer while extending across the width of the object.

By making the first line longer in this way, the laser scan head can achieve a higher scan speed and/or a higher average scan speed. The inertia of moving parts, such as rotating mirrors, in the laser scan head does not substantially affect the average scan speed. In this way, the laser scan head can achieve a maximum scanning speed, for example. The maximum scan speed is the maximum scan speed for which the laser scan head is designed. By comparison, if the first line were as short as its width, the slowness of the moving parts would limit the average scanning speed. For example, the laser scan head could not reach the maximum scanning speed.

It should be noted that the scan length required to obtain the maximum scan speed, the amount of inertia of the moving parts and the maximum speed

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BE2023/5055 depend on the design of the laser scan head. If a particular laser scan head cannot reach its maximum scan speed, or only achieves maximum scan speed for a small portion of the scan movement while irradiating a line perpendicular to the direction of transport, the scan speed can be increased by applying the line at the skew angle. Due to the increased scanning speed, the amount of irradiated area per unit of time increases.

In one embodiment, the first line extends over a scan width of the object. The scanning width is perpendicular to the transport direction. The laser scan head is configured to have a first average scan speed for a scan motion over a length of the scan width. The laser scan head is configured to have a second average scan speed for the first scan pass. The second average scan speed is higher than the first average scan speed.

According to this embodiment, the laser scanning head has a certain average scanning speed when irradiating a line with the length of the scanning width. The scan width is the width of the surface of the object to be irradiated. Because the scan width is too short, the laser scan head would not reach maximum average scan speed when performing a scan move over the length of the scan width. Due to the skew angle, the first line is longer than the scan width. The increased length allows the laser scan head to achieve a higher average scan speed, for example the maximum average scan speed, when irradiating the first line.

In one embodiment, the laser device comprises a further laser scan head for directing a further laser beam at the object. The further laser scanning head and the laser scanning head are arranged relative to each other along the direction perpendicular to the conveying direction. The controller is configured to control the further laser scan head to perform a further first scan move of the further laser beam and a further second scan move of the further laser beam. The control unit is configured to control the transport unit to move the object and the further laser scanning head relative to each other in the transport direction during the further first scanning movement and during the further second scanning movement. The further laser scan head is configured to perform the further first scan move by moving the further laser beam along a further first scan direction to irradiate a further first line on the object. The further laser scanning head is configured to perform the further second scan move by moving the further laser beam along a further second scanning direction to irradiate a further second line on the object. The further first scanning direction extends over at least part of the width of the object. The width is in a direction perpendicular to the direction of transport. The further second scanning direction extends over at least part of the width of the object opposite to the

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BE2023/5055 further first scanning direction. The controller is configured to control the further second scan direction based on the further first scan direction and a further vector in the transport direction.

According to this embodiment, another laser scanning head is arranged next to the laser scanning head in the direction of the width of the object. For example, the laser scan head and the further laser scan head are aligned in the direction of the width, or are arranged at an offset. The laser scan head and the further laser scan head are arranged side by side in such a way that part of the object is irradiated via the laser scan head and another part of the object via the further laser scan head. For example, the laser scanning head irradiates a left side of the object, while the further laser scanning head irradiates a right side of the object. For example, there is a small portion of the object that is irradiated by both laser scan heads, for example along a centerline of the object. Irradiating the small area through both laser scan heads ensures that this area is properly irradiated.

The further laser scan head irradiates different lines than the laser scan head. The further laser scanning head performs a scanning movement similar to the laser scanning head. However, the directions and/or speeds of the further first scanning movement and the further second scanning movement are, for example, different from the first scanning movement and the second scanning movement, respectively. The further laser scan directs the laser beam for the further scanning movement along the further second scanning direction. The control unit controls the further second scanning direction on the basis of the further first scanning direction and the further vector in the transport direction. The further vector is the same as the vector in the transport direction, or is different from the vector in the transport direction. By controlling on the basis of the further vector in the transport direction, the further second scanning direction is not parallel to the further first scanning direction. In this way, the further second scanning direction takes into account the movement of the further laser scanning head relative to the object during the further second scanning movement. As a result, the further laser scan head can irradiate the further second line more accurately with respect to the first line in order to obtain a more uniform irradiation of the object.

By arranging the two laser scan heads next to each other, more area can be irradiated per unit time compared to providing a single laser scan head with twice the amount of laser power. For example, using the two laser scan heads with a laser power of 100 W each results in significantly more irradiated area per unit time compared to using a single laser scan head with a laser power of 200 W. High power laser sources with a high pulse frequency are readily available. However, laser scan heads can't scan fast enough to distribute all that power over an object in a short time. By using

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BE2023/5055 using two laser scan heads, each laser scan head only needs to scan part of the width, for example only half the width. In this way, the two laser scan heads can distribute double the amount of laser power in the same time, increasing the amount of irradiated area per unit time.

In one embodiment, the laser scan head and the further laser scan head are arranged to apply the first line and the further first line next to each other on the object, and to apply the second line and the further second line next to each other on the object.

According to this embodiment, the first line and the further first line are adjacent to each other, and the second line and the further second line are adjacent to each other. Because the lines are adjacent to each other, a continuously irradiated surface is created by the two laser scan heads.

In this way, a wide surface of the object can be efficiently irradiated. The lines are adjacent without overlapping or overlapping each other. For example, the overlap is 5% or 10% or 20% of the diameter of the laser beam.

In one embodiment, the laser device is a laser cleaning device.

According to this embodiment, the laser device is adapted to remove contamination from the object.

In one embodiment, a laser scanning head is provided for use in the laser device according to any of the above embodiments.

In an Embodiment, a controller is provided for use in the laser device according to any of the above embodiments.

In a second aspect of the invention, a method is provided for irradiating an object with a laser beam. The method includes the steps of: aiming the laser beam with a laser scanning head at the object, performing a first scanning movement with the laser scanning head by moving the laser beam along a first scanning direction to irradiate a first line on the object, while the object and the laser scanning head are moved relative to each other in the transport direction, performing a second scanning movement with the laser scanning head by moving the laser beam along a second scanning direction to irradiate a second line on the object, while moving the object and the laser scanning head in the transport direction toward are moved relative to each other. The first scanning direction extends over at least part of a width of the object. The width is in a direction perpendicular to the direction of transport. The second scanning direction extends over at least part of the width of the object opposite to the first scanning direction. The method includes the step of controlling the second scan direction based on the first scan direction and a vector in the transport direction.

In one embodiment, the method comprises the step of applying the first line and the second line to the object parallel to each other.

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In one embodiment, the method comprises the step of applying the first line and the second line next to each other on the object.

In one embodiment, the method includes the step of moving the laser beam along the second scan direction to irradiate the second line at a scan rate. The step of controlling the second scanning direction based on the vector in the transport direction includes controlling the second scanning direction based on the scanning speed.

In one embodiment, the method comprises the step of moving the object and the laser scan head relative to each other in the transport direction at a transport speed. The step of controlling the second scanning direction based on the vector in the transport direction includes controlling the second scanning direction based on the transport speed.

In one embodiment, the method includes the step of controlling the second scan direction based on the first scan direction comprising controlling the second scan direction based on an inverse of the first scan direction.

In one embodiment, the method comprises the steps of: starting the first scan move at a first start point on the first line, stopping the first scan move at a first end point on the first line, starting the second scan move at a second start point on the second line, stopping the second scanning motion at a second end point on the second line, applying the first end point and the second start point to the object at a distance from each other. The distance is in a direction perpendicular to the first line. The distance is equal to or less than a diameter of the laser beam.

In one embodiment, the method comprises the steps of: applying the laser beam in a first laser start position to irradiate the first start point, applying the laser beam in a first laser end position to irradiate the first end point, applying the laser beam in a second laser start position to irradiate the second start point, applying the laser beam in a second laser end position to irradiate the second end point, applying the laser beam in the second laser start position opposite to the transport direction of the laser beam in the first laser end position. The first laser start position, the first laser end position, the second laser start position, and the second laser end position are relative to the laser scan head.

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In an embodiment, the method comprising the step of performing the first scanning movement comprises irradiating the first line, the first line making an oblique angle with the direction of transport.

In one embodiment, the method comprises the steps of: providing a further laser scan head to direct a further laser beam onto the object, performing the method according to any of claims 24-30 with the further laser scan head to direct a further first line and a irradiating the second first line, applying the further first line adjacent to the first line, applying the further second line adjacent to the second line.

In a third aspect of the invention, a computer program is provided with instructions which, when executed by a control unit of a laser device, the laser device comprising a laser scan head for directing a laser beam at an object, and a transport unit for transferring the object and the laser scan head to relative to each other causes the control unit to perform the method according to one of the above embodiments.

The invention will be explained in more detail below with reference to the figures, which show exemplary embodiments of the invention in a non-limiting manner.

The figures show in:

fig. 1: a first embodiment of a laser device according to the invention.

Figs. 2A-2B: irradiating the first line according to the first embodiment.

Figs. 3A-3B: irradiating the second line according to the first embodiment.

fig. 4: The first and second scanning directions according to the first embodiment.

fig. 5: The first and second scanning direction according to a second embodiment of the invention.

fig. 6: the amount of irradiated surface per unit time according to the invention.

fig. 7: a third embodiment of a laser device according to the invention.

fig. 8: a fourth embodiment of the invention.

fig. 9: a method according to an embodiment of the invention.

To clarify the invention, a Cartesian coordinate system has been included in the figures.

fig. 1 shows a first embodiment of a laser device 100 according to the invention. The laser device 100 is for irradiating an object 101 with a laser beam 102. The laser device 100 is, for example, a laser cleaning device. The laser scanning head 103 is to direct the laser beam 102 towards the object 101. The transport unit 104 is around

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BE2023/5055 to move object 101 and the laser scan head 103 relative to each other. The controller 105 is configured to control the laser scan head 103 to perform a first scanning movement of the laser beam 102 and a second scanning movement of the laser beam 102 . The control unit 105 is configured to control the transport unit 104 to move the object 101 and the laser scan head 103 relative to each other in a transport direction 113 during the first scanning movement and during the second scanning movement. The transport direction 113 is indicated by the arrow and is directed in the x direction.

The laser scan head 103 is configured to perform the first scan move by moving the laser beam 102 along a first scan direction 111 to irradiate a first line 121 on the object 101 . The laser scan head 103 is configured to perform the second scan move by moving the laser beam along a second scan direction 112 to irradiate a second line 122 on the object 101 . The first scanning direction 111 extends over at least part of a width of the object 101.

The width is in a direction perpendicular to the transport direction 113, i.e. in the y-direction. The second scanning direction 112 extends over at least part of the width of the object 101 opposite to the first scanning direction 111. As shown in FIG. 1, the first scan direction 111 is mostly in the positive y direction, while the second scan direction 112 is mostly in the negative y direction.

The controller 105 is configured to control the laser scan head 103 to apply the first line 121 and the second line 122 on the object 101 parallel to each other.

The first line 121 is perpendicular to the transport direction 113. The lines in Figs. 1 are shown separated from each other to clearly show the individual lines. In practice, the lines are adjacent and may partially overlap to form a continuously irradiated surface on the object 101.

The laser scan head 103 includes at least one mirror and at least one galvo scanner motor. The at least one mirror is arranged to reflect the laser beam 102 to the object 101 . The at least one galvo scanner motor is configured to rotate the at least one mirror. The controller 105 is configured to control the at least one galvo scanner motor to control the first scan move and the second scan move. For example, the laser scan head 103 has two mirrors and two galvo scanner motors, one for each mirror. The two mirrors are rotatable by the two galvo scanner motors to move the laser beam 102 over the object 101 in a two-dimensional plane.

Figs. 2A and 2B show the irradiation of the first line 121 according to the first embodiment. The laser scan head 103 starts the first scan move by irradiating the first starting point 221 on the first line 121, as shown in Figure 2A. While the object

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BE2023/5055 101 moves in the transport direction 113, the laser beam 102 moves along the first scanning direction 111. The laser beam 102 is a pulsed laser beam that provides laser pulses 200 to the object 101 at a certain frequency as it moves along the first scanning direction. The laser pulses 200 are indicated by the circles. Note that there is some overlap between the laser pulses 200. As the object 101 moves in the direction of transport 113, the laser beam 102 moves to the right of the figure.

In the situation of Fig. 2B, the laser scan head 103 has completed its first scanning movement and has just irradiated the first end point 222 of the first line 121 . The result of the first scanning movement is that the first line 121 is irradiated with the laser pulses 200 as indicated by the solid lines. The laser pulses 200 indicated by the dotted lines indicate how the first line 121 was irradiated in the time before the situation in figure 2B.

The first line 121 has moved in the transport direction 113 by a distance 202. The distance 202 corresponds to a diameter of the cross-section of the laser beam 102.

Figs. 3A and 3B show the irradiation of the second line 122 according to the first embodiment. The laser scan head 103 starts the second scan move by irradiating the second starting point 321 on the second line 122, as shown in Figure 3A. The laser scan head 103 is configured to position the first end point 222 and the second start point 321 on the object 101 at a distance 202 from each other. The distance 202 is in a direction perpendicular to the first line 121. The distance 202 is equal to the diameter of the laser beam 102. Optionally, the distance 202 is smaller than the diameter of the laser beam 102. Optionally, the distance 202 has a component perpendicular to the transport direction 113.

As the object 101 moves in the transport direction 113, the laser beam 102 moves along the second scanning direction 112. The laser beam 102 applies laser pulses 200 to the object 101 at a certain frequency as it moves along the second scanning direction 112 .

As the object 101 moves in the transport direction 113, the laser beam 102 moves to the left of the figure.

In the situation of Fig. 3B, the laser scan head 103 has completed the second scan pass and has just irradiated the second end point 322 of the second line 122 . The result of the second scan move is that the second line 122 is irradiated with the laser pulses as indicated by the solid lines. The laser pulses 200 indicated by the dotted lines indicate how the second line 122 was irradiated in the time before the situation in Figure 3B.

The controller 105 is configured to control the laser scan head 103 to juxtapose the first line 121 and the second line 122.

The laser scan head 103 is configured to perform the first scanning pass to irradiate a third line 321 on the object 101 . The third line 321 is located at the location

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BE2023/5055 indicated by the dotted line. From the point of view of the laser scan head 103, the third line 321 is located where the second line 122 was in the situation of Figure 3A. The laser scan head 103 is configured to start the third scan move at a third start point 331 on the third line 321, and to stop the third scan move at a third end point 332 on the third line 321. The first line 121 and the third line 321 are located located on opposite sides of the second line 122.

fig. 4 shows the first scanning direction 111 and second scanning direction 112 according to the first embodiment. The first scanning direction 111 is directed from the bottom left to the top right in the figure. The first scanning direction 111 extends in the transport direction 113 and in the width direction. The first scanning direction 111 has a transport direction component 113 and a width direction component. The angle of the first scanning direction 111 is set in relation to the transport speed and the scanning speed to irradiate the first line 121 perpendicular to the transport direction 113.

When the first scan is completed, the laser beam 102 is aimed at the right side of the figure. During the second scan move, the laser beam 102 moves from the right side of the figure to the left side.

The controller 105 is configured to control the second scan direction 112 based on the first scan direction 111 and a vector 402 in the transport direction 113. The vector 402 is shown in FIG. 4. The controller 105 is configured to control the second scan direction 112 based on an inverse 400 of the first scan direction 111. However, if the laser beam 102 moved in the direction of the inverse 400, the second line 122 would be at a large angle relative to the first line 121. The large angle would be caused by the movement of the object 101 in the transport direction 113, and caused by the component of the inverse 400 in the direction opposite the transport direction 113. Therefore, the control unit 105 takes the vector 402 in the transport direction 113.

The vector 402 in the transport direction 113 is based on a scan speed of the second scan move. The scan speed is a speed at which the laser scan head 103 moves the laser beam 102 along the second scan direction 112 to irradiate the second line 122 . The control unit 105 is configured to control the transport unit 104 to move the object 101 and the laser scanning heads 103 relative to each other in the transport direction 113 at a transport speed. The vector 402 in the transport direction 113 is based on the transport speed. Optionally, the vector 402 is based on only one of the scan rate and the transport rate. For example, the second scan direction is a sum of the vector 402 of the inverse 400 and the vector 402 in the transport direction 113. Considering the vector 402 in the transport direction 113, the second scan direction is

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BE2023/5055 112 directed from the bottom right in the figure to the top left. Due to the second scanning direction 112, the second line 122 is arranged parallel to the first line 121.

The laser scan head 103 is configured to apply the laser beam 102 to a first laser start position 411 to irradiate the first start point 221, to apply the laser beam 102 to a first laser end position 412 to irradiate the first end point 222, to irradiate the laser beam 102 in arranging a second laser start position 421 to irradiate the second starting point 321, and arranging the laser beam 102 at a second laser end position 422 to irradiate the second end point 322 . The first laser start position 411, the first laser end position 412, the second laser start position 421 and the second laser end position 422 are relative to the laser scan head 103. The laser beam 102 in the second laser start position 421 is arranged opposite the transport direction 113 with respect to the laser beam 102 in the first laser end position 412.

The laser scanning head 103 directs the laser beam 102 to the first laser start position 411 to irradiate the third start point 331 . The laser scan head 103 directs the laser beam 102 to the first laser end position 412 to irradiate the third end point 332 .

fig. 5 shows the first scanning direction 111 and the second scanning direction 112 according to a second Embodiment of the invention. For example, the second embodiment has the same elements as the first embodiment, except for the following. For example, the second embodiment includes the laser device 100 of the first embodiment, or at least part of the laser device 100 of the first embodiment.

The laser scan head 103 is configured to irradiate the first line 121, with the first line 121 having an oblique angle 50 DEG with respect to the direction of travel 113. The first line 121 extends along a scan width 502 of the object 101. The scan width 502 is perpendicular to the transport direction 113. The scan width 502 is the width of the surface of the object 101 to be irradiated by the laser beam 102.

The laser scan head 103 is configured to have a first average scan speed for a scan move along a length of the scan width 502. The laser scan head 103 is configured to have a second average scan speed for the first scan move. The second average scan speed is higher than the first average scan speed. As is clear from FIG. 5, by arranging the first line 121 at the slant angle 500, the length of the first line 121 is substantially longer than the scanning width 502. As a result, the laser scanning head 103 can achieve a higher average scanning speed when irradiating the first line 121 Similarly, the average scan speed of the second scan pass is higher.

Note that the first scan direction 111 and the second scan direction 112 of the second embodiment are similar to the first scan direction 111 and the second scan direction 112 of the first Embodiment, except that they are rotated about the oblique angle 500 of the

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BE2023/5055 first line 121 available. The skew angle 500 can be selected between 0 and 90 degrees to obtain a desired length of the first line 121 where the average scan rate is high or maximum.

fig. 6 shows an example of the amount of irradiated area per unit time according to the invention. The x-axis indicates the scan width 502 in mm. The y-axis shows the amount of irradiated surface per unit time in m2/hour.

Line 601 indicates the output of irradiating a zigzag pattern using a known laser device 100. Because of the zigzag pattern, the transport speed must be low to ensure that the zigzag lines are sufficiently adjacent. Furthermore, for a small scan width 502 of less than 40 mm, the transport speed is further reduced because the laser scan head 103 cannot move the laser beam 102 back and forth fast enough across the width of the object 101. The inertia of the moving parts of the laser scan head 103 prevent the laser beam 102 from moving back and forth faster.

Line 602 indicates the output of the first embodiment of the invention. Because the first embodiment has the controller 105 configured to control the second scan direction 112 based on the first scan direction 111 and the vector 402, good irradiation of the object 101 is obtained at a much higher transport speed, about twice as fast as with the zigzag pattern. As shown, the output is limited for scan width 502 of less than 40 mm because the laser scan head 103 cannot move the laser beam 102 faster along the first scan move and the second scan move due to the inertia of the moving parts of the laser scan head 103. At a scan width 502 of 40 mm and larger, the laser scan head 103 can achieve a maximum average scanning speed.

Line 603 indicates the output of the second embodiment of the invention.

Because of the slant angle 500 of the first line 121, a first line 121 of 40 mm or more can be scanned by the laser scan head 103 for a scan width 502 of less than 40 mm. In this way, the laser scanning head 103 is able to achieve the maximum average scanning speed independent of the scanning width 502. As a result, the second Embodiment has a high output independent of the scanning width 502.

fig. 7 shows a third embodiment of a laser device 100 according to the invention. For example, the third embodiment has the same elements as the first embodiment and/or as the second embodiment, except for the following.

The laser device 100 comprises a further laser scanning head 703 for directing a further laser beam 702 onto the object 101. The further laser scanning head 703 and the laser scanning head 103 are arranged relative to each other along the direction perpendicular to the transport direction 113. The further laser scanning head 703 and the laser scanning head 103 are arranged side by side in the y direction.

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The control unit 105 is configured to control the further laser scan head 703 to perform a further first scan move of the further laser beam 702 and a further second scan move of the further laser beam 702. The control unit 105 is configured to control the transport unit 104 to move the object 101 and the further laser scanning head 703 relative to each other in the transport direction 113 during the further first scanning movement and during the further second scanning movement. The further laser scan head 703 is configured to perform the further first scan move by moving the further laser beam 702 along a further first scan direction 711 to irradiate a further first line 721 on the object 101 .

The further laser scan head 703 is configured to perform the further second scan move by moving the further laser beam 702 along a further second scanning direction 712 to irradiate a further second line 822 on the object 101 . The further first scanning direction 711 extends over at least part of the width of the object 101.

The width is in a direction perpendicular to the transport direction 113. The further second scanning direction 712 extends over at least part of the width of the object 101 opposite to the further first scanning direction 711. The control unit 105 is configured to define the further second scanning direction 712 on the basis of the further first scan direction 711 and a further vector in the transport direction 113.

For example, the further vector is determined in the same way as the vector 402 as explained in the first embodiment and shown in Figure 4.

The laser scanning head 103 and the further laser scanning head 703 are arranged to irradiate the first line 121 and the further first line 721 adjacent to each other on the object 101, and to irradiate the second line 122 and the further second line 822 adjacent to each other on the object 101 to irradiate. The second further line 822 is shown in FIG. 8. As shown in FIG. 7, the first line 121 and the further first line 721 together form a single continuous line.

Similarly, the second line 122 and the further second line 822 together form a single continuous line.

fig. 8 shows a fourth embodiment of the invention. The fourth embodiment is a combination of the second embodiment and the third embodiment. The control unit 105 is configured to apply the first line 121 and the second line 122 at the oblique angle 50 DEG, and to mount the further first line 721 and the further second line 822 at a further oblique angle 80 DEG with respect to the conveying direction 113. to bring. The further first scanning movement and the further second scanning movement are mirror-symmetrical in the transport direction 113 with respect to the first scanning movement and the second scanning movement. As a result, the irradiated pattern formed by the first line 121, the second line 122, the further first line 721 and the further second line 822 is a V-shaped pattern. The lines may partially overlap in the tip of the V-shaped

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BE2023/5055 pattern on the centerline of the object 101 to ensure that the surface is well irradiated near the tip of the V-shaped pattern.

The laser scan head 103 irradiates the left half 801 of the object 101. The further laser scan head 703 irradiates the right half 802 of the object 101.

fig. 9 shows a method according to an embodiment of the invention. The method is to irradiate the object 101 with the laser beam 102. The method includes the step 900 of directing the laser beam 102 with a laser scan head 103 onto the object 101. The method includes the step 901 of performing the first scanning move with the laser scanning head 103 by moving the laser beam 102 along the first scanning direction 111 to irradiate the first line 121 on the object 101, while moving the object 101 and the laser scanning head 103 relative to each other in the conveying direction 113. The method includes the step 902 of performing the second scanning move with the laser scanning head 103 by moving the laser beam 102 along the second scanning direction 112 to irradiate a second line 122 on the object 101 while moving the object 101 and the laser scanning head 103 relative to each other in the transport direction 113. The first scanning direction 111 extends over at least part of the width of the object 101.

The width is in a direction perpendicular to the transport direction 113. The second scanning direction 112 extends over at least part of the width of the object 101 opposite to the first scanning direction 111. The method includes the step 903 of controlling the second scan direction 112 based on the first scan direction 111 and the vector 402 in the transport direction 113.

This document describes detailed embodiments of the invention. However, it is to be understood that the embodiments described are exemplary only and the invention may be implemented in other forms.

Claims (32)

2023/5055 25 BE2023/5055 CONCLUSIONS A laser device (100) for irradiating an object (101) with a laser beam (102), comprising: a laser scanning head (103) for directing the laser beam (102) onto the object (101); a transport unit (104) for moving the object (101) and the laser scanning head (103) relative to each other; a controller (105) configured to control the laser scanning head (103) to perform a first scanning movement of the laser beam (102) and a second scanning movement of the laser beam (102); wherein the control unit (105) is configured to control the transport unit (104) to move the object (101) and the laser scan head (103) relative to each other in a transport direction (113) during the first scanning movement and during the second scanning movement; wherein the laser scanning head (103) is configured to perform a first scanning movement by moving the laser beam (102) along a first scanning direction (111) to irradiate a first line (121) on the object (101), wherein the laser scanning head ( 103) is configured to perform second scanning motion by moving the laser beam (102) along a second scanning direction (112) to irradiate a second line (122) on the object (101), with the first scanning direction (111) extending over at least part of a width of the object (101), the width being perpendicular to the transport direction (113), the second scanning direction (112) extending over at least part of the width of the object (101) opposite to the first scan direction (111), the controller (105) being configured to control the second scan direction (112) based on the first scan direction (111) and a vector (402) in the transport direction (113). The laser device (100) of claim 1, wherein the controller (105) is configured to control the laser scan head (103) to make the first line (121) and the second line (122) on the object (101) parallel to each other. places. The laser device (100) of claim 2, wherein the controller (105) is configured to control the laser scan head (103) to juxtapose the first line (121) and the second line (122). 2023/5055 26 BE2023/5055 A laser device (100) according to any one of the preceding claims, wherein the vector (402) in the transport direction (113) is based on a scanning speed of the second scanning movement; wherein the scan speed is a speed at which the laser scan head (103) moves the laser beam (102) along the second scanning direction (112) to irradiate the second line (122). A laser device (100) according to any one of the preceding claims, wherein the control unit (105) is configured to control the transport unit (104) to move the object (101) and the laser scanning head (103) relative to each other in the transport direction (113). ) to move at a transport speed, where the vector (402) in the transport direction (113) is based on the transport speed. The laser device (100) of claim 4 or 5, wherein the controller (105) is configured to control the second scan direction (112) based on an inverse (400) of the first scan direction (111). The laser device (100) of any preceding claim, wherein the laser scan head (103) comprises at least one mirror and at least one galvo scanner motor; the at least one mirror being positioned to reflect the laser beam (102) toward the object (101), the at least one galvo scanner motor being configured to rotate the at least one mirror; wherein the controller (105) is configured to drive the at least one galvo... scanner motor to control the first scan move and the second scan move. A laser device (100) according to any one of the preceding claims, wherein the laser scan head (103) is configured to start the first scan move at a first start point (221) on the first line (121), to stop the first scan move at a first end point (222) on the first line (121), to start the second scan move at a second start point (321) on the second line (122), to stop the second scan move at a second end point (322) on the second line (122), 2023/5055 27 BE2023/5055 where the laser scan head (103) is configured to position the first end point (222) and the second start point (321) on the object (101) at a distance (202) from each other, where the distance ( 202) is perpendicular to the first line (121), the distance (202) being equal to or less than a diameter of the laser beam (102). The laser device (100) of claim 8, wherein the distance (202) is less than 80% of the diameter of the laser beam (102). The laser device (100) of claim 8 or 9, wherein the laser scan head (103) is configured to: position the laser beam (102) at a first laser start position (411) to irradiate the first start point (221); position the laser beam (102) at a first laser end position (412) to irradiate the first end point (222); position the laser beam (102) at a second laser start position (421) to irradiate the second start point (321); position the laser beam (102) at a second laser end position (422) to irradiate the second end point (322); wherein the first laser start position (411), the first laser end position (412), the second laser start position (421), and the second laser end position (422) are relative to the laser scanning head (103); wherein the laser beam (102) in the second laser start position (421) is placed opposite to the transport direction (113) with respect to the laser beam (102) in the first laser end position (412). The laser device (100) of claim 9, wherein the second laser start position (421) is the same as the first laser end position (412). A laser device (100) according to claim 9 or 10, wherein the laser beam (102) is positioned in the second laser end position (422) in the transport direction (113) relative to the laser beam (102) in the first laser start position (411). The laser device (100) of claim 12, wherein the laser scanning head (103) is configured to perform the first scanning motion to irradiate a third line (321) on the object (101); wherein the laser scan head (103) is configured to: 2023/5055 28 BE2023/5055 start the third scan move at a third start point (331) on the third line (321), stop the third scan move at a third end point (332) on the third line (321), the laser beam ( 102) to the first laser start position (411) to irradiate the third start point (331); directing the laser beam (102) to the first laser end position (412) to irradiate the third end point (332); wherein the first line (121) and the third line (321) are on opposite sides of the second line (122). A laser device (100) according to any one of the preceding claims, wherein the laser scan head (103) is configured to irradiate the first line (121), the first line (121) being perpendicular to the transport direction (113). The laser device (100) of any one of claims 1 to 13, wherein the laser scan head (103) is configured to irradiate the first line (121), the first line (121) having an oblique angle (500) relative to the transport direction (113). The laser device (100) of claim 15, wherein the first line (121) extends over a scanning width (502) of the object (101), the scanning width (502) being perpendicular to the transport direction (113), the laser scanning head (103) is configured to have a first average scan speed for a scan move over a length of the scan width (502), the laser scan head (103) being configured to have a second average scan speed for the first scan move, the second average scan speed higher than the first average scan rate. A laser device (100) according to any one of the preceding claims, comprising a further laser scan head (703) for directing a further laser beam (702) onto the object (101), the further laser scan head (703) and the laser scan head (103 ) are arranged relative to each other along the direction perpendicular to the transport direction (113), the controller (105) being configured to control the further laser scanning head (703) to perform a further first scanning movement of the further laser beam (702) and a further perform second scanning movement of the further laser beam (702), 2023/5055 29 BE2023/5055 wherein the control unit (105) is configured to control the transport unit (104) to move the object (101) and the further laser scanning head (703) relative to each other in the transport direction (113) during the further first scanning movement and during the further second scanning movement; with the further laser scan head (703) configured, perform the further first scan move by moving the further laser beam (702) along a further first scan direction (711) to irradiate a further first line (721) on the object (101) wherein the further laser scan head (703) is configured to perform the further second scan move by moving the further laser beam (702) along a further second scanning direction (712) to create a further second line (822) on the object (101). irradiating, wherein the further first scanning direction (711) extends over at least part of the width of the object (101), wherein the further second scanning direction (712) extends over at least part of the width of the object (101 ) opposite to the further first scan direction (711), the controller (105) being configured to control the further second scan direction (712) based on the further first scan direction (711) and a further vector in the transport direction (113). The laser device (100) of claim 17, wherein the laser scan head (103) and the further laser scan head (703) are arranged to position the first line (121) and the further first line (721) side by side on the object (101) , and to place the second line (122) and the further second line (822) side by side on the object (101). A laser device (100) according to any one of the preceding claims, wherein the laser device (100) is a laser cleaning device. A laser scanning head (103) for use in the laser device (100) according to any one of claims 1 to 19. A control unit (105) for use in the laser device (100) according to any one of claims 1 to 19. 22. A method of irradiating an object (101) with a laser beam (102), the method comprising the steps of: directing the laser beam (102) with a laser scanning head (103) at the object (101), performing a first scanning movement with the laser scanning head (103) by moving the laser beam (102) along a first scanning direction (111) to irradiate a first line (121) on the object (101), while the object (101) and the laser scanning head (103) are moved relative to each other in a transport direction (113); performing a second scan move with the laser scan head (103) by moving the laser beam (102) along a second scanning direction (112) to irradiate a second line (122) on the object (101) while the object (101) and the laser scanning heads (103) are moved relative to each other in the transport direction (113), the first scanning direction (111) extending over at least part of a width of the object (101), the width perpendicular to the transport direction ( 113), wherein the second scan direction (112) extends across at least a portion of the width of the object (101) opposite to the first scan direction (111), the method comprising the step of controlling the second scan direction ( 112) based on the first scanning direction (111) and a vector (402) in the transport direction (113). The method of claim 22, including the step of aligning the first line (121) and the second line (122) on the object (101) parallel to each other. The method of claim 23, including the step of juxtaposing the first line (121) and the second line (122) on the object (101). The method of any one of claims 22 to 24, including the step of moving the laser beam (102) along the second scanning direction (112) to irradiate the second line (122) at a scanning speed; wherein the step of controlling the second scanning direction (112) based on the vector (402) in the transport direction (113) comprises controlling the second scanning direction (112) based on the scanning speed. The method of claim 25, comprising the step of moving the object (101) and the laser scanning head (103) relative to each other in the transport direction (113) at a transport speed; wherein the step of controlling the second scan direction (112) based on the vector (402) in the transport direction (113) comprises controlling the second scan direction (112) based on the transport speed. 2023/5055 31 BE2023/5055 The method of any one of claims 22 to 26, wherein the step of controlling the second scanning direction (112) based on the first scanning direction (111) comprises controlling the second scanning direction (112) based on a inverse (400) of the first scanning direction (111). The method of any one of claims 22 to 27, comprising the steps of: starting the first scan move at a first start point (221) on the first line (121), stopping the first scan move at a first end point (222) on the first line (121), start the second scan move at a second start point (321) on the second line (122), stop the second scan move at a second end point (322) on the second line (122), positioning the first end point (222) and the second start point (321) on the object (101) at a distance (202) from each other, the distance (202) being perpendicular to the first line (121), wherein the distance (202) is equal to or less than a diameter of the laser beam (102). The method of any one of claims 22 to 28, comprising the steps of: placing the laser beam (102) at a first laser start position (411) to irradiate the first starting point (221), placing the laser beam (102) at a first laser end position (412) to irradiate the first end point (222); placing the laser beam (102) at a second laser start position (421) to irradiate the second start point (321); placing the laser beam (102) at a second laser end position (422) to irradiate the second end point (322); placing the laser beam (102) in the second laser start position (421) opposite to the transport direction (113) of the laser beam (102) in the first laser end position (412): wherein the first laser start position (411), the first laser end position (412) , the second laser start position (421) and the second laser end position (422) are relative to the laser scan head (103). 2023/5055 32 BE2023/5055 The method of any one of claims 22 to 29, wherein the step of performing the first scanning pass comprises irradiating the first line (121), the first line (121) having an oblique angle (500) relative to relative to the transport direction (113). A method according to any one of claims 22 to 30, comprising the steps of: providing a further laser scan head (703) for directing a further laser beam (702) onto the object (101), performing the method according to any one of claims 22 to 30 with the further laser scanning head (703) to irradiate a further first line (721) and a second first line (121), arranging the further first line (721) next to the first line (121), arranging the further second line (822) next to the second line (122). 32. Computer program containing instructions which, when executed by a control unit (105) of a laser device (100), the laser device (100) comprising a laser scanning head (103) for directing a laser beam (102) at an object (101 ), and a transport unit (104) for moving the object (101) and the laser scan head (103) relative to each other, causing the control unit (105) to perform the method according to any one of claims 22 to 31.