MIRRORS

TECHNICAL FIELD

The invention relates to an object sorting device comprising a control unit and a transport unit comprising an inlet for receiving the objects, an outlet for the objects from the transport unit after sorting and a transport substrate for transporting the objects at specific positions after the inlet and before the outlet, the object sorting device comprising an illumination unit configured to illuminate the objects and a sensor unit configured to receive light from the objects after illumination. The invention further relates to an illumination unit and a method for an object sorting device.

BACKGROUND ART

Object sorting devices are well-known in the art with the aim to sort out e.g. grains with different properties and/or quality. It is known for long to use a light source in the form of laser or light emitting diodes that switches on and off to illuminate a specific grain to be analyzed. Both laser and light emitting diodes are emitting light with a specific narrow range of wavelengths. A single broad-spectrum light source, i.e. an incandescent lamp, cannot be switched on and off at the required frequency. Hence, one problem with using today’s light sources is a limitation to certain wavelengths.

Hence, there is a need for an improved object sorting device.

SUMMARY OF INVENTION

The object of the present invention is to remedy the problems known in the prior art by using a light source that allows for a broader wavelength spectrum.

For the sole reason of more easily explaining the invention, reference is made to an orthogonal system having a longitudinal extension, a width extension and a height extension. For rotating items, reference is made to cylindrical coordinates having a longitudinal extension and a radial extension being perpendicular to the longitudinal direction.

The invention relates to an illumination unit and an object sorting device using such an illumination unit. The object sorting device comprises a control unit and a transport unit comprising an inlet for receiving the objects and a transport substrate for transporting the objects at specific positions after the inlet. The object sorting device comprises the illumination unit configured to illuminate the objects and a sensor unit configured to receive light from the objects after illumination. The illumination unit comprises a light source and a mirror array comprising a multitude of pivotable mirrors configured by way of pivotal movement to intermittently guide light from the light source to predetermined specific positions dependent on synchronization signals from the control unit. The sensor unit is configured to identify one or more properties of the objects in the predetermined specific positions and configured to feed information on properties to the control unit.

One advantage here is that the pivotable mirrors allows for intermittently illuminating one or more specific objects at chosen specific positions at high frequency. The pivotable mirrors are mechanical devices where the mirrors advantageously are positioned on a substrate that can control the movement of the mirrors between at least two positions. The movement of the mirrors between the two positions is very quick and allows for a rapid intermittent illumination and at the same time saving the light source from having to be turned on and off. The movement of the micromirrors allows for intermittent illumination of the objects during a time interval as short as in the range of microseconds which allows for the use of a broad- spectrum illumination unit, for example an incandescent lamp or the like, to be used in larger scale.

According to one example, the object sorting device comprises an outlet from the transport unit after sorting, wherein the transport substrate is positioned between the inlet and the outlet. Here, inlet refers to a position where the objects enter the sorting device and outlet refers to where the objects leave the sorting device.

One advantage here is that the outlet can be used to convey and/or direct the objects to different collection units dependent on the different properties of the objects.

According to one example, the object sorting device comprises an ejector unit, wherein the control unit is configured to control the ejector unit to expel objects in the predetermined specific positions with different properties to different positions. According to one example, the ejector unit is arranged in connection to the outlet, wherein the control unit is configured to control the ejector unit to expel objects in the predetermined specific positions with different properties to different positions in the outlet.

One advantage here is that the ejector unit can direct objects of same quality to the same position in the outlet and thereby contribute to sorting the objects and/or direct the objects to the different collection units dependent on the different properties of the objects. The collection units can be any suitable arrangements configured to receive the objects, e.g. vessels and/or further conveyer devices and/or a packaging machine and/or a further sorting device sorting the objects further.

The mirrors are micromirror devices, each configured to be pivoted between an active position and an inactive position dependent on a control signal from the control unit, wherein the active position relates to illuminating the predetermined specific positions during a predetermined time period. Here, it should be noted that one or more mirrors can be used to illuminate the same object. The micromirror devices are advantageously arranged in a substrate being a semiconductor substrate where each mirror can be moved electrostatically between the active and inactive position. The semiconductor substrate is directly or indirectly connected to the control unit and moves the mirrors dependent on control signals from the control unit. The micromirrors are advantageously arranged such that the active and inactive positions are digital positions in the sense that the micromirrors switches between only these two positions. Each mirror is arranged at a first angle in the active position and a different and second angle in the inactive position. The first and second angles depend on a chosen illumination angle from the illumination unit.

According to one example, the transport substrate is configured with through openings and/or a transparent or at least translucent material through which the light can pass in order to hit the object and to be further guided towards the sensor unit. The illumination unit can be positioned on either side of the transport substrate and the sensor unit on the other side. The through openings are configured with a form that allows passage of light but the object fixing device in conjunction with the through opening are configured such that the object cannot slip through the through opening. Each through opening may for example be elongated wider than the object such that light hits and passes the object, but narrow enough to hinder the object from slipping through the through opening. It should be noted that the transport substrate may comprise a multitude of object fixing devices allowing a multitude of objects to be secured in place at the same time. The object fixing device secures each object in a specific position. The object fixing device could comprise a sensor, not shown, that observes movements of the objects and calculates speed and position in time for the control unit to use calculating the synchronization signal. As an alternative, the object fixing device can be a unit, e.g. part of the control unit or connected to the control unit, that uses information on position of object fixing devices and movement of the transport substrate for the control unit to use calculating the synchronization signal. Here, the control unit is advantageously connected to the transport substrate for detecting and/or controlling movement of the transport substrate. According to one example, the illumination unit comprises light guides between the mirrors and the objects, wherein one or more predetermined mirrors are configured to guide light to predetermined light guides configured to convey light from the light source to the objects. Also here, one or more predetermined mirrors can be used to illuminate one or more of the light guides. Advantageously, the mirror array comprises a multitude of mirrors that can illuminate several different objects at the same time via multitude of light guides. The light guides are advantageously in the form of light guiding fibers that can be configured in a straight line or in a curved manner or a combination. Hence, one light guide may comprise at least one straight portion and at least one curved portion. It is also possible to arrange the fibers such that at least one is straight and one curved. One advantage of using light guides is that the light source can be positioned at a considerable distance from and/or at an angle to the objects removing risk of stray light. The light guides furthermore have the advantage of precisely illuminating the predetermined objects. The light guides have the further advantage of providing design solutions giving more or less light intensity dependent on number of fibers that illuminates an object. One light guide provides a predetermined light intensity, but adding several light guides adds further light intensity to the object. Another possibility is to design the diameter of the light guide dependent on desired light intensity, i.e. a larger diameter gives more light intensity than a smaller diameter. For example, sorting malting barley (grains) demands more light intensity than sorting durum wheat when applying the invention to near infrared transmittance (NIT) sorting. The invention thus provides the possibility of designing the illumination unit with more light guides when sorting durum wheat compared to sorting malting barley (grains), with a given diameter of the light guides. However, since the diameter of the light guides provide for different amount of light intensity, then the number of light guides can be reduced if the diameter is increased. Hence, a number of light guides can be divided into differently sized bundles illuminating an object dependent on the nature of the object and/or the diameter of the light guide can be designed accordingly. The light guide also allows for a more airtight arrangement that prevents soiling of the illumination unit due to e.g. dust.

According to one example, one or more predetermined mirrors are configured to guide light to one predetermined light guide configured to convey light from the light source to the one object or wherein one or more predetermined mirrors are configured to guide light to at least two predetermined light guides configured to convey light from the light source to one object. According to one example there is one light guide connected to a specific mirror, but as an alternative there are at least two light guides connected to a specific mirror. Here, “connected to” means that the light guides are positioned in the vicinity of the mirrors.

According to one example, the illumination unit comprises at least one lens focusing light from the one or more predetermined mirrors to a predetermined light guide or light guides. Here, the lens is positioned between one or more mirrors and one or more fibers. This has the advantage of focusing the light from the mirror to the one or more fibers. When using a multitude of mirrors the lens focuses the light from the different mirrors to a correct focal point for illuminating the fiber or fibers used for illuminating the predetermined object.

According to one example, the illumination unit comprises at least one additional lens focusing light from the light source to the one or more predetermined mirrors. Here, the lens is positioned between light source and the one or more mirrors. This has the advantage of focusing the light from the light source to the one or more mirrors. When using a multitude of mirrors the lens focuses the light from the light source to a correct focal point for illuminating the one or more mirrors.

According to one example, the mirrors are configured with a flat surface or a curved surface. The lens is accordingly shaped dependent on the configuration of the mirrors. The lens is further shaped dependent on, inter alia, light source, distance to the light source, distance to the light guide or guides and number of light guides

According to one example, the transport substrate is a rotating drum comprising object fixing devices configured to hold the objects in the specific positions. The rotating drum has an extension in a longitudinal direction and is delimited in a radial direction by an envelope surface. The rotating drum uses the centripetal force from the rotation of the drum to keep the objects in place on an inner surface of the envelope surface. The object fixing devices is advantageously indentations in the inner surface of the envelope surface. The indentations may be in the form of indentations of a smooth inner surface or indentations in elevations extending in a direction from the inner surface towards the rotational center of the rotating drum. However, the object fixing devices may be any suitable fixing means that can hold the objects in place during rotation. The rotating drum is configured with through openings in the envelope surface through which the light can pass in order to hit the object and to be further guided towards the sensor unit. The through openings may be void of material or may comprise a transparent or at least translucent material. The illumination unit can be positioned within the drum and the sensor unit outside the drum, or vice versa. The through opening is configured with a form that allows passage of light but the object fixing device in conjunction with the through opening are configured such that the object cannot slip through the through opening. The through opening may for example be elongated wider than the object such that light hits and passes the object, but narrow enough to hinder the object from slipping through the through opening. It should be noted that the rotating drum may comprise a multitude of object fixing devices allowing a multitude of objects to be secured in place at the same time. According to the above, the number of fibers, lenses and sensors correspond to the number of bottom surfaces and through openings illuminated. The object fixing device secures each object in a specific position. The object fixing device could comprise a sensor that observes movements of the objects and calculates speed and position in time for the control unit to use calculating the synchronization signal. As an alternative, the object fixing device can be a unit, e.g. part of the control unit or connected to the control unit, that uses information on position of object fixing devices and rotational speed for the control unit to use calculating the synchronization signal. Here, the control unit is connected to the rotating drum for detecting and/or controlling to rotational speed of the rotating drum.

According to one example, the transport substrate is a guide plate for conveying the objects along the guide plate, wherein the specific positions are determined in time with relation to speed of the objects along the guide plate. The guide plate has a longitudinal direction and a width direction comprising a bottom surface extending in the longitudinal direction and the width direction and side walls extending in the longitudinal direction and a height direction. The side walls delimiting the bottom surface in the width direction. The guide plate advantageously has a declining extension from the inlet to the outlet, such that the objects can slide and/ or roll down the guide plate between the side walls with the aid of gravity. According to one example, the guide plate is configured with through openings in the bottom surface through which the light can pass in order to hit the object and to be further guided towards the sensor. The illumination unit can be positioned on either side of the guide plate with respect to the bottom surface, and the sensor unit is positioned on the opposite side of the bottom surface. As an alternative, the illumination unit can be positioned on either one side of the guide plate with respect to the bottom surface, and the sensor unit is positioned on the same side using reflected light from the object. Each through opening is configured with a form that allows passage of light but the object fixing device in conjunction with the through opening are configured such that the object cannot slip through the through opening. The through opening may for example be elongated wider than the object such that light hits and passes the object, but narrow enough to hinder the object from slipping through the through opening. As an alternative to using through openings, the bottom surface can be made from a transparent or at least a translucent material through which the light can pass in order to illuminate the object. It should be noted that the guiding plate may comprise a multitude of bottom surfaces and walls allowing a multitude of objects to pass at the same time. According to the above, the number of fibers, lenses and sensors correspond to the number of bottom surfaces and through openings illuminated. Here, it should be noted that an object fixing device could be a sensor that observes movements of the objects and calculates speed and position in time for the control unit to use calculating the synchronization signal. As an alternative, the object fixing device can be a unit, e.g. part of the control unit or connected to the control unit, that uses information on degree of declination, i.e. angle towards gravity, and initial speed and position in time for the control unit to use calculating the synchronization signal. The sorting device can as an alternative be configured such that at least one object with a specific property is allowed to pass the ejectors and simply fall to a collector due to gravity after the transport guiding plate.

According to one example, the ejector unit comprises an air pushing unit controlled by the control unit and configured to exert a predetermined air flux on the objects in the predetermined specific positions dependent on identified properties. Here, the ejector unit can be configured to exert different air flux dependent on identified properties. The ejector unit is also timed with the speed of the object in order to give the object a trajectory dependent on identified property. One object may be given a less air flux than another resulting in different trajectories and the possibility to collect objects with same properties in a chosen position corresponding to the trajectory. For the rotating drum, the ejector unit gives a less air flux for a trajectory closer to the inner surface of the rotating drum than a more intense air flux. For the guiding plate, the ejector unit gives a less air flux for a trajectory closer to the guiding plate than a more intense air flux. It should be noted that for the drum, the ejector unit operates in a direction towards the center of rotation and for the guiding plate at least at an angle to a gravity normal.

According to one example, the ejector unit comprises several air pushing units at different positions along the transport substrate being controlled by the control unit and configured to exert a predetermined air flux on the objects in the predetermined specific positions at a position along the transport substrate dependent on identified properties. The different ejectors positioned along the travelling path of the object give different trajectories merely by its different positions. Hence, the ejectors may operate with a similar air flux or with a difference in air flux.

With reference to the above example, the transport substrate comprises at least one through opening per ejector unit positioned in connection to each ejector unit such that the ejector unit can push out the object via e.g. air flux from one side of the transport substrate and through the through opening forcing the object into the trajectory previously described. As an alternative, one or more ejector units are configured after the transport substrate and configured to push the object out of its path after having left the transport substrate into a trajectory as previously described. Here, the direction of the trajectory is a design choice, for example in a trajectory starting at least partly against the gravity, or in a trajectory starting at least partly with the gravity.

The ejector unit is connected to any suitable source of compressed air and the ejector unit may comprise valves opening and closing in a predetermined manner in order to give a predetermined air pulse for the object to be expelled. The ejector unit may comprise one or more air conduits between the source of compressed air and the ejector unit and/or air conduits leading to one or more through openings.

The objects are advantageously cereals such as barley, wheat, durum wheat or oats and the properties can be color and/or shape and/or density and/or protein content and/or starch content and/or fungus disease and/or chosen kind of infection and/or any other suitable characteristics. The objects are however not limited to cereals, but may be a pill, plastics parts, beads, beans or any other suitable object that could be sorted dependent on chosen properties.

The sensor may be any suitable sensor dependent on sought after properties, for example a spectrometer with inGaAs-detector and/or Si-detector or any other sensor arrangement and/or an optical filter arrangement, band pass filter, prism or the like. A multi-channel spectrometer is especially advantageous in connection to the illumination unit.

The light guides can be any suitable light guide, for example optical fiber, rods of glass or acrylic glass, or a combination of different types of light guides.

It should be noted that all units being controlled by the control unit is connected to the control unit via any suitable connecting means, for example electrically or via light guides. All units controlled by the control unit comprises suitable devices for executing a task decided and controlled by the control unit. For example, the illumination unit may comprise switches for turning the light on or off and suitable means for adjusting light intensity and luminous flux.

The invention also refers to a method for an object sorting device according to any one of the above examples, wherein the method comprises the steps:

-transporting an object on a transport substrate,

-identifying a specific position of the object on the transport substrate,

- intermittently illuminating an object by use of an illumination unit comprising a light source and a mirror array comprising a multitude of pivotable mirrors, the step of illuminating comprising the step of controlling the mirrors to pivot to an active position when illuminating the object and to an inactive position when not.

According to one example, the step of illuminating comprises the step of constant illumination during the intermit illumination.

According to one example, the step of illuminating comprises the step of collecting light from one or more mirror via a lens before guiding the light via a light guide to the object.

-receiving light from the object to a sensor unit,

-a control unit receiving information from the sensor unit identifying property of the object,

According to one example, the method comprises the step that the control unit is controlling an ejector unit to expel the object from the transport substrate dependent on identified property.

The steps are repeated during a continuous sorting process and the step of intermittent illumination depends on the speed of the object on the transport substrate. The faster the object travels, the shorter the time frame for illumination. The light intensity and/or luminous flux further depends on the speed of the object and thus the time frame for illumination. The shorter the time frame, the more intensity and/or luminous flux is needed.

For all examples above, the light source is advantageously a constantly illuminating light source and the intermittent illumination is made solely by use of the mirrors. The advantage here is that any suitable light source can be chosen giving the possibility to choose wavelength spectrum. The lamp can, for example, be a fluorescent lamp, a xenon lamp or an incandescent lamp, but is not limited to the examples-Furthermore, the illumination unit advantageously comprises a reflector focusing the light from the light source towards the mirrors, either directly or via the additional lens. It should be noted that the additional lens could be used in any one of the examples above and/or that the reflector could be used in any one of the examples above.

BRIEF DESCRIPTION OF DRAWINGS

The invention will below be explained in more detail in connection to a number of drawings, wherein:

Fig. 1 schematically shows an example of an object sorting device;

Fig. 2 schematically shows a mirror array according to one example;

Fig. 3 schematically shows an example of an object sorting device;

Fig. 4 schematically shows an example of an object sorting device;

Fig. 5 schematically shows an example of an object sorting device;

Fig. 6 schematically shows an example of an object sorting device;

Fig. 7 schematically shows an example of an object sorting device comprising a rotating drum;

Fig. 8 schematically shows an example of an object sorting device comprising a rotating drum;

Fig. 9 schematically shows an example of an object sorting device comprising a rotating drum;

Fig. 10 schematically shows an example of an object sorting device comprising a rotating drum;

Fig. 11 schematically shows an example of an object sorting device comprising a guide plate;

Fig. 12 schematically shows an example of an object sorting device comprising a guide plate, and wherein;

Fig. 13 schematically shows a flow chart of a method according to the invention with the steps marked and referred to as boxes with reference to figure 13. DETAILED DESCRIPTION

The invention will below be explained in connection to a number of schematic drawings representing a number of example embodiments. In the drawings, same objects have the same reference numbers in all drawings.

Figure 1 schematically shows an object sorting device 1 comprising a control unit 2 and a transport unit 3 comprising an inlet 4 for receiving the objects, an outlet 6 for expelling the objects 5 from the transport unit 3 after sorting and a transport substrate 7 for transporting the objects 5 at specific positions 7a after the inlet 4 and before the outlet 6. The object sorting device 1 comprises an illumination unit 8 configured to illuminate the objects 5 and a sensor unit 9 configured to receive light from the objects 5 after illumination. The illumination unit 8 comprising a light source 10 and a mirror array 11 comprising a multitude of pivotable mirrors 12 configured by way of pivotal movement to intermittently guide light from the light source 10 to predetermined specific positions 7a dependent on synchronization signals from the control unit 2. The sensor unit 9 is configured to identify one or more properties of the objects 5 in the predetermined specific positions 7a and configured to feed information on properties to the control unit 2. The sorting device comprises an ejector unit 13 in connection to the outlet 6. The control unit 2 is configured to control the ejector unit 13 to expel objects 5 in the predetermined specific positions 7a with different properties to different positions in the outlet 6.

The transport substrate 7 is configured with through openings 26 through which the light can pass in order to hit the object 5 and to be further guided towards the sensor unit 9. The illumination unit 8 can be positioned on either side of the transport substrate and the sensor unit 9 on the other side. The through openings 26 are configured with a form that allows passage of light but the object fixing device 19 in conjunction with the through opening 26 are configured such that the object 5 cannot slip through the through opening 26. The through opening 26 may for example be elongated wider than the object 5 such that light hits and passes the object 5, but narrow enough to hinder the object 5 from slipping through the through opening 26. It should be noted that the transport substrate 7 may comprise a multitude of object fixing devices 19 allowing a multitude of objects 5 to be secured in place at the same time. The object fixing device 19 secures each object 5 in a specific position. The object fixing device 19 could comprise a sensor, not shown, that observes movements of the objects and calculates speed and position in time for the control unit to use calculating the synchronization signal. As an alternative, the object fixing device can be a unit, e.g. part of the control unit or connected to the control unit, that uses information on position of object fixing devices and movement of the transport substrate 7 for the control unit to use calculating the synchronization signal. Here, the control unit is connected to the transport substrate 7 for detecting and/or controlling movement of the transport substrate 7.

Figure 2 schematically shows a mirror array 11 according to one example, wherein the mirrors 12 are micromirror devices, each configured to be pivoted between an active position 14 and an inactive position 15 dependent on a control signal from the control unit 2, wherein the active position 14 relates to illuminating the predetermined specific positions 7a during a predetermined time period. In figure 2, the active positions 14 are shown as squares with white color and the inactive positions are shown with grey color. The number of mirrors are dependent on e.g. what type of transport substrate 7 used and what type of light guide arrangement used and what type of mirror arrangement used, but is not limited to the numbers shown in figure 2. The number of mirrors can be less than in figure 2, but may also be many thousands. The mirror arrangement can also be arranged as sections of mirrors 12 arranged next to each other with one light source 10 connected to each section of mirrors 12. The illumination unit 8 may be arranged such that one light source illuminates a sub-section of mirrors 12 or all mirrors 12 in the mirror arrangement 11, wherein the angle of the mirrors control illumination of the object. The mirror array in figure 2 is represented in figures 1 and 3-11 with one or more devices 11, 12 and can be seen as either one or more mirrors 12 in the array being active 14 or inactive 15, or as one or more arrays 11 comprising one or more mirrors 12 in the array being active 14 or inactive 15. The mirrors 12 can be arranged in the mirror array 11 in any suitable shape, e.g. a rectangular pattern as in figure 2 and/or quadratic pattern and/or a zig-zag pattern and/or a honeycomb pattern or a combination of patterns. The mirrors 12 can be configured in any suitable form, for example rectangular as in figure 2 and/or quadratic and/or elliptic and/or round and/or triangular and/or any suitable polygon shape and/or a combination of forms.

Figure 3 schematically shows an example of an object sorting device similar to figure 1. In figure 3 the illumination unit 8 comprises light guides 16 between the mirrors and the objects 5, wherein one or more predetermined mirrors are configured to guide light to one predetermined light guide 16 configured to convey light from the light source 10 to one object 5. As an alternative, one or more predetermined mirrors are configured to guide light to at least two predetermined light guides 16 configured to convey light from the light source 10 to one object.

According to one example, one light guide 16 is connected to a specific mirror 12. According to another example, there are at least two light guides 16 connected to a specific mirror 12.

In figures 3-11 the illumination unit 8 comprises at least one lens 17 focusing light from the one or more predetermined mirrors 12 to a predetermined light guide 16 or light guides 16. The lens can be connected to one mirror 12 as in figures 3-5 and 7-12, but can also be connected to a number of mirrors as shown in figure 6.

Figures 4 and 5 schematically show examples of an object sorting device according to figures 1-3, but in figures 4 and 5 at least one mirror 12 is shown in an inactive position 15. Figure 5 schematically shows that the active mirror 14 is arranged in combination with a lens 17, one or more light guides 16 and one or more additional light guides 30. Figure 5 schematically shows that the inactive mirror 15 is arranged to directly illuminate the object 5 when active, i.e. there is no lighting guide 16 connected to the inactive mirror 15 nor is there an additional lighting guide 30 configured in alignment with the inactive mirror 15. Figure 5 thus schematically shows that different types of illumination arrangement can be used for the sorting device 1. In figures 4-6, the additional lighting guides 30 are positioned on an opposite side of the object 5 with reference to the lighting guides 16. The additional lighting guides 30 are configured to collect and direct the light from the object 5 to the sensor unit 9.

Figures 7-10 schematically show examples of an object sorting device comprising a rotating drum 18. Here, the transport substrate 7 is a rotating drum 18 comprising object fixing devices 19 configured to hold the objects 5 in the specific positions 7a. In figures 7-10 the control unit 2 is not shown, but the examples shown in figures 7-10 comprises a control unit according to what is shown in figures 1 and 3-6 and 10. The control unit is connected to the illumination unit 8, mirror array 12, the sensor unit 9, the ejector unit 13 and to the transport substrate 7 at least when the transport substrate is in the form of a rotating drum 18 or any other moving transport substrate 7.

The rotating drum 18 has an extension in a longitudinal direction X and is delimited in a radial direction R by an envelope surface 22. The rotating drum 18 uses the centripetal force from the rotation of the drum 18 to keep the objects in place on an inner surface 23 of the envelope surface 22. The object fixing devices 19 are advantageously indentations 24 in the inner surface 23 of the envelope surface 22. The indentations 24 may be in the form of indentations of a smooth inner surface or indentations in elevations 25 extending in a direction from the inner surface 23 towards the rotational center of the rotating drum 18. However, the object fixing devices 19 may be any suitable fixing means that can hold the objects in place during rotation. The rotating drum 18 is configured with through openings 26 in the envelope surface 22 through which the light can pass in order to hit the object 5 and to be further guided towards the sensor unit 9. The illumination unit 8 can be positioned within the drum 18 and the sensor unit 9 outside the drum 18, or vice versa. The through openings 26 are configured with a form that allows passage of light but the object fixing device 19 in conjunction with the through opening 26 are configured such that the object 5 cannot slip through the through opening 26. The through opening 26 may for example be elongated wider than the object 5 such that light hits and passes the object 5, but narrow enough to hinder the object 5 from slipping through the through opening 26. It should be noted that the rotating drum may comprise a multitude of object fixing devices 19 allowing a multitude of objects to be secured in place at the same time. According to the above, the number of fibers, lenses and sensors correspond to the number of bottom surfaces and through openings illuminated. The object fixing device 19 secures each object 5 in a specific position. The object fixing device 19 could comprise a sensor, not shown, that observes movements of the objects and calculates speed and position in time for the control unit to use calculating the synchronization signal.

As an alternative, the object fixing device can be a unit, e.g. part of the control unit or connected to the control unit, that uses information on position of object fixing devices and rotational speed for the control unit to use calculating the synchronization signal. Here, the control unit is connected to the rotating drum for detecting and/or controlling to rotational speed of the rotating drum 18.

Figure 11 schematically shows an example of an object sorting device 1 comprising a guide plate 20. Here, the transport substrate 7 is a guide plate 20 for conveying the objects 5 along the guide plate 20, wherein the specific positions 7a are determined in time with relation to speed of the objects 5 along the guide plate 20. The guide plate 20 has a longitudinal direction X and a width direction Y comprising a bottom surface 27 extending in the longitudinal direction X and the width direction Y and side walls 28 extending in the longitudinal direction X and a height direction Z. The side walls 28 delimiting the bottom surface 27 in the width direction Y. The guide plate 20 advantageously has a declining extension from the inlet 4 to the outlet 6, such that the objects 5 can slide and/or roll down the guide plate 20 between the side walls 28 with the aid of gravity. The guide plate 20 is configured with through openings 26 in the bottom surface 27 and/or the side walls 28 through which the light can pass in order to hit the object 5 and to be further guided towards the sensor 9. The illumination unit 8 can be positioned on either side of the guide plate 20 with respect to the bottom surface and/or the side walls, and the sensor unit 9 is positioned on the opposite side of the bottom surface 27 and/or the side walls. Each through opening 26 is configured with a form that allows passage of light but the object fixing device in conjunction with the through opening are configured such that the object cannot slip through the through opening. The through opening may for example be elongated wider than the object such that light hits and passes the object, but narrow enough to hinder the object from slipping through the through opening. It should be noted that the guiding plate may comprise a multitude of bottom surfaces and walls allowing a multitude of objects to pass at the same time. According to the above, the number of fibers, lenses and sensors correspond to the number of bottom surfaces and through openings illuminated. Here, it should be noted that an object fixing device could be a sensor that observes movements of the objects and calculates speed and position in time for the control unit to use calculating the synchronization signal. As an alternative, the object fixing device can be a unit, e.g. part of the control unit or connected to the control unit, that uses information on degree of declination, i.e. angle towards gravity, and initial speed and position in time for the control unit to use calculating the synchronization signal.

Figure 12 schematically shows an example of an object sorting device 1 comprising a guide plate 20 similar to figure 11. In figure 12 there are no through openings 26 as in figure 11 and the illumination unit 8 is positioned such that it illuminates the object 5 from an underside of the bottom surface 27, i.e. through the bottom surface 27. Here, underside refers to a side of the bottom surface 27 opposite to a surface on which the object rolls and/or slides. Figure 12 shows an alternative to using through openings, where the bottom surface is made from a transparent material or at least a translucent material through which the light can pass in order to illuminate the object. However, also here the illumination unit 8 can be positioned on either side of the guide plate 20 with respect to the bottom surface, and the sensor unit can be positioned on the opposite side or positioned on the same side using reflected light from the object.

Figure 12 further shows an additional lens 31 positioned between the light source 10 and the mirror array 11 for focusing light from the light source to one or more specific mirrors 12. Figure 12 also shows that the illumination unit comprises a reflector 32 focusing the light from the light source towards the mirrors, either directly such as in figure 11 or via the additional lens 31 in figure 12. It should be noted that the additional lens 31 in figure 12 could be used in any one of the examples shown in figures 1-11 and/or that the reflector could be used in any one of the examples in figures 1-11. As example of this, the additional lens 31 and the reflector 32 have been shown in figures 7 and 8.

In figures 1-12, the ejector unit 13 comprises an air pushing unit 13 controlled by the control unit 2 and configured to exert a predetermined air flux on the objects 5 in the predetermined specific positions 7a dependent on identified properties.

Figures 11 and 12 further show the possibility to allow one object 5 to pass the ejector unit or ejector units 13 and drop out of the transport substrate 7 under the effect of gravity. It should be noted, not shown, that an ejector unit 13 can be positioned after the transport substrate 11 and configured to push the object 5 after having left the transport substrate 11 in a suitable direction and corresponding trajectory. Figures 11 and 12 show that the sorting device 1 comprises two collectors 21 in the outlet 6, but the outlet may comprise one collector 21 arranged to collect the objects 5 in different positions or any suitable number of collectors 21 suitable to sort the objects 5.

Figures 9 and 10 show that the objects sorting device comprises one ejector unit 13 configured to exert different air flux to the object 5 dependent on identified property. The different air flux forces the object into different trajectories, shown with dotted lines, in order for the objects 5 to land at different positions in a collector 21 arrange in connection to the outlet 6.

Figures 7, 8, 11 and 12 show that the ejector unit 13 comprises several air pushing units 13 at different positions along the transport substrate 7 being controlled by the control unit 2 and configured to exert a predetermined air flux on the objects 5 in the predetermined specific positions 7a at positions along the transport substrate 7 dependent on identified properties.

The air flux from the ejector units 13 at different positions forces objects in different positions into different trajectories, shown with dotted lines, in order for the objects 5 to land at different positions in a collector 21 arrange in connection to the outlet 6.

With reference to figures 1-12, the transport substrate 7 comprises at least one through opening 29 per ejector unit 13 positioned in connection to each ejector unit 13 such that the ejector unit 13 can push out the object 5 via e.g. air flux from one side of the transport substrate 7 and through the through opening 29 forcing the object 5 into the trajectory previously described. The mirrors 12 are configured with a flat surface or a curved surface.

According to one example, the object sorting device 1 comprises additional light guides 30 positioned between the object 5 and the sensor 9 for receiving light from having hit the object 5 from the illumination unit 8.

Figure 13 schematically shows a flow chart of a method according to the invention with the steps marked and referred to as boxes with reference to figure 13.

The invention also refers to a method for an object sorting device according to any one of the examples in figures 1-11, wherein the method comprises the steps:

Box 101

-transporting an object 5 on a transport substrate 7,

Box 102

-identifying a specific position of the object 5 on the transport substrate 5,

Box 103

- intermittently illuminating an object 5 by use of an illumination unit 8 comprising a light source 10 and a mirror array 11 comprising a multitude of pivotable mirrors 12, the step of illuminating comprising the step of controlling the mirrors 12 to pivot to an active position when illuminating the object 5 and to an inactive position when not,

According to one example, the step of illuminating comprises the step of constant illumination during the intermit illumination.

According to one example, the step of illuminating comprises the step of collecting light from one or more mirrors (12) via a lens before guiding the light via a light guide (16) to the object.

Box 104

-receiving light from the object 5 to a sensor unit 9,

Box 105

-a control unit (2) receiving information from the sensor unit (9) identifying property of the object (9),

According to one example, the method further comprises the step in Box 106 -the control unit (2) controlling an ejector unit (13) to expel the object (5) from the transport substrate (7) dependent on identified property.

The steps are repeated during a continuous sorting process and the step of intermittent illumination in Box 103 depends on the speed of the object on the transport substrate. The faster the object travels, the shorter the time frame for illumination. The light intensity and/or luminous flux further depends on the speed of the object and thus the time frame for illumination. The shorter the time frame, the more intensity and/or luminous flux is needed.

For all examples above, the light source is advantageously a constantly illuminating light source. The advantage here is that any suitable light source can be chosen giving the possibility to choose wavelength spectrum. The lamp can, for example, be a fluorescent lamp, a xenon lamp or an incandescent lamp, but is not limited to the examples.