EP3427847A1

EP3427847A1 - Sorting station for mail items and method for sorting mail items

Info

Publication number: EP3427847A1
Application number: EP17181179.7A
Authority: EP
Inventors: Marc Sorgeloos; Kevin Paindeville; Hans Heggemans
Original assignee: Bpost NV
Current assignee: Bpost NV
Priority date: 2017-07-13
Filing date: 2017-07-13
Publication date: 2019-01-16

Abstract

The present invention relates to a sorting station and sorting system for mail items utilizing a capacitive sensor for detection of the sorted mail items, and a use thereof. Also provided herein is a method for the sorting of mail items based on the capacitive detection of the placement or removal of a mail item, particularly using the sorting station and sorting system of the present invention.

Description

FIELD OF THE INVENTION

The present invention relates to a sorting station and sorting system for mail items and the use thereof. The present invention also relates to a method for sorting mail items.

BACKGROUND OF THE INVENTION

The sorting of mail items is usually performed overnight in preparation for daytime distribution by a postal delivery service, such as a mailman. Examples of mail items include postal letters, envelopes, plastic wrapped magazines, and the like. Advantageously, the mail items are sorted in a way that allows a continuous distribution along a pre-planned route. This way the delivery service can perform its delivery task in a timely and resource efficient manner.
The majority of mail sorting is performed automatically using mechanical sorting systems employing, for instance conveyor belts, gripper mechanisms, and the like, their operation being based on the automated detection of the mail item's parameter and designation address. However, many mail items cannot be sorted via the automated mechanical sorting systems. This is due to a number of reasons, including illegible handwriting, wrong letter formatting, damaged packaging, reflective covers, and so on. As a result, these incompatible mail items require a manual sorting to properly sort and organize them for delivery, and/or to merge them with the (previously) mechanically sorted mail items.
The manual sorting of mail items is a process, prone to (human) errors, resulting in a mail item being incorrectly sorted and misplaced. Each misplaced mail item decreases the efficiency and timeliness of the mail delivery. For instance, the misplaced item, sorted and designated to an incorrect delivery route, cannot be delivered to the correct address and the mail item needs to be returned to the sorting station, or the delivery service has delivered the mail item to the wrong address and may have to return to the missed delivery address. Since delivery services handles thousands or millions of mail items daily, the combined cost of time and resources lost for correcting the misplacement of wrongly sorted mail items quickly adds up.
While some measures can be taken to reduce the chance of a (human) sorting error occurring, such sorting errors cannot be prevented completely.
For instance, performing continuous check-ups on the manually sorted items may prevent the incorrect sorting, but is counterproductive to both the proficiency desired by and the resources available to a mail delivery company. In addition, human errors may also occur when unloading sorted mail items from a pre-sorted stack. For example, the items can be transferred into the delivery bags in the wrong order, or can be accidentally mixed up with other sorted items.
In addition, at present, delivery deadlines increasingly become shorter and stricter, resulting in a considerable time pressure to perform the actual sorting and delivery of mail items. This further increases the risk of incorrect sorting a mail item, despite any measures to prevent the sorting errors.
Thus, although there are several methods known to minimize or compensate for these types of sorting error, these measures are often quite costly, still prone to errors, approximate, slow, and/or valid for only a small sub-group of the incompatible mail items. Hence, it is an aim of the invention to overcome the problems of the art. In particular, there is a need for improved systems, devices and/or methods that can handle repeatedly sorting a high volume of mail items, particularly mail items which cannot be sorted automatically, without the aforementioned drawbacks.

SUMMARY OF THE INVENTION

A first aspect of the present application provides a sorting station for mail items comprising:

a plurality of detection units, each detection unit comprising,
- o a compartment defining a volume configured for holding a mail item;
- o at least one capacitive sensor integrated into a wall of the compartment and configured for capacitively sensing the placement or removal of a mail item placed in the compartment; and
- o at least one identification means configured for designating or labelling the detection unit or compartment;
a control unit connected to the plurality of detection units and configured for registering the placement or removal of a mail item in or from a compartment of the detection unit by the capacitive sensor; and
a housing (190) adapted for supporting the plurality of detection units (100).

In particular embodiments, the capacitive sensor comprises two or more capacitive sensor plates, wherein each capacitive sensor plate is integrated into opposite and/or adjacent sidewalls of the corresponding compartment and arranged to avoid a parallel and/or lateral overlap of the capacitive detection area.
In particular embodiments, the capacitive sensor integrated in the sidewall has a layer stack setup.
In particular embodiments, at least one of the detection units comprises (a) a vertical compartment configured for holding a mail item aligned in a vertical direction, or (b) a horizontal compartment configured for holding a mail item aligned in a horizontal direction.
In particular embodiments, the identification means of a detection unit comprises an optical source, preferably a LED, and wherein the control unit is configured for managing and controlling the optical source.
Another aspect of the present application provides a sorting system, comprising

at least one sorting station, preferably at least two sorting stations according to the present application; any of claims 1 to 5; and
a central control unit, configured for providing instructions to an operator, preferably via a display unit, and/or to the at least one sorting station, preferably to the at least two sorting stations. In particular embodiments, the central control unit is situated on a sorting station.

Another aspect of the present application provides a method for sorting mail items, particularly using a sorting station according to the present application, comprising the steps of:

(a) providing a mail item;
(b) designating a detection unit of a sorting station according to the present application to receive the mail item, thus obtaining a designated detection unit;
(c) placing the mail item in a detection unit, preferably manually;
(d) capacitively sensing the placement of the mail item in a detection unit;
(e) verifying that the mail item was placed in the detection unit designated in step (b) and registering an error if the mail item was not placed in the detection unit designated in step (b);

In particular embodiments, step (b) of the method comprises the steps of:

(b1) designating a detection unit to receive the mail item; and
(b2) displaying or presenting instructions to the operator of the sorting station which detection unit is designated.

Preferably, the method further comprises the step of (b3) activating one or more identification means, said identification means being an optical source, for identifying the detection unit designated in step (b).
Preferably, the method further comprises the step of activating one or more identification means, said identification means being an optical source for informing the operator in case an error is registered in step (e). This may include activating the optical source being the identification means of the detection unit erroneously containing the mail item and/or activating the optical source of the detection unit designated in step (b).
In particular embodiments, the method further comprises activating the identification means of a plurality of detection units, adjacent to or in the vicinity of the designated detection unit of step (b), said identification means being an optical source, and said identification means of said plurality of detection units being activated in an optically distinguishable manner, such as a different colour or blinking frequency.
In particular embodiments, step (a) of the method comprises the steps of (a1) providing a mail item; and (a2) identifying the mail item with a mail identification input unit.
In particular embodiments, the method further comprises (f) repeating the steps (a) to (e) for at least one different mail item and (g) removing the sorted mail items from the sorting station, preferably manually.
In particular embodiments, the present application provides a method for merging a first group of sorted mail items and a second group of sorted mail items, particularly using a sorting station according to the present application, comprising the steps of:

(a) sorting mail items via a method according to the present application, thus obtaining a first group of sorted mail items;
(b) providing a second group of sorted mail items, preferably sorted by automated mechanical means;
(c) merging a mail item of the first group of sorted mail items with the second group of sorted mail items;

(c1) selecting or designating a sorted mail item from the first group of sorted mail items;
(c2) designating a detection unit that holds the selected sorted mail item of step (c1);
(c3) removing the selected sorted mail item from the designated detection unit of step (c2), preferably manually;
(c4) capacitively sensing the removal of the sorted mail item from the designated detection unit of step (c2);
(c5) verifying that the selected sorted mail item was removed from the designated detection unit of step (c2) and registering an error if the selected mail item was not removed from the designated detection unit of step (c2);
(c6) merging the removed selected sorted mail item with the second group of sorted mail items.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description of the figures of specific embodiments of the invention is merely exemplary in nature and is not intended to limit the present teachings, their application or uses.

FIGURE 1A-1D show a schematic representation of an exemplary embodiment of a detection unit of the present application, wherein particularly the different components of the capacitive sensor (sensing plate, ground and shield/guard) are located in a single layer or plane and integrated in a sidewall of the detection unit. Figure 1A is a schematic representation of a plurality of detection units according to an exemplary embodiment of the invention. Figures 1B and 1C represent a side view of a first and a second sensor setup, wherein the first and second sensor setup is located or integrated in a first and second sidewall, respectively, of a detection unit. Figure 1D is schematic representation depicting a top view of a plurality of detection units according to an exemplary embodiment of the invention and also illustrates the different capacitive sensing channels of an arrangement of a plurality of detection units.
FIGURE 2A-2D show a schematic representation of an exemplary embodiment of a detection unit of the present application wherein particularly the different components of the capacitive sensor (sensing plate, ground, guard/shield) are stacked in multiple layers and integrated in a sidewall of the detection unit. Figure 2A represents a side view of an exemplary sensor setup, implemented in a PCB and located/integrated in a sidewall of a detection unit. Figure 2B is a schematic representation depicting a top view of an arrangement of a plurality of detection units according to an exemplary embodiment of the invention. Side walls 2A correspond to the sensor setup presented in Figure 2A. The markings "Grd" and "Gnd" indicate "guard" and "ground", respectively. 2C marks a cross section of a side wall, further expanded in Figure 2C. Figure 2B also illustrates the capacitive sensing channels of an arrangement of a plurality of detection units. Figure 2C schematically represents the stacked layer setup of an embodiment of the capacitive sensor. Figure 2D schematically represents different (conducting) layers of the stacked layer of Figure 2C.
FIGURE 3A is a schematic illustration of a sorting system comprising several sorting stations according to an exemplary embodiment of the invention. The sorting station only shows a plurality of slots wherein the sidewalls of the different detection units can be mounted - the (sidewalls of the) vertical compartments are not shown. FIGURE 3B is a schematic illustration of a detail of a sorting station according to an exemplary embodiment of the invention. The sorting station only shows a plurality of slots wherein the sidewalls of the different detection units can be mounted - the (sidewalls of the) vertical compartments are not shown.

DETAILED DESCRIPTION OF THE INVENTION

Before the present is described, it is to be understood that this invention is not limited to the particular devices, systems, methods, or combinations described, since such devices, systems, methods, or combinations may, of course, vary. It is also to be understood that the terminology used herein is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.
As used herein, the singular forms "a", "an", and "the" include both singular and plural referents unless the context clearly dictates otherwise.
The terms "comprising", "comprises" and "comprised of' as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. It will be appreciated that the terms "comprising", "comprises" and "comprised of" as used herein comprise the terms "consisting of", "consists" and "consists of".
The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within the respective ranges, as well as the recited endpoints.
Whereas the terms "one or more" or "at least one", such as one or more or at least one member(s) of a group of members, is clear per se, by means of further exemplification, the term encompasses inter alia a reference to any one of said members, or to any two or more of said members, such as, e.g., any ≥3, ≥4, ≥5, ≥6 or ≥7 etc. of said members, and up to all said members.
All references cited in the present specification are hereby incorporated by reference in their entirety. In particular, the teachings of all references herein specifically referred to are incorporated by reference.
Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.
In the following passages, different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.
In the present description of the invention, reference is made to the accompanying drawings and figures that form a part hereof, and in which are shown by way of illustration only of specific embodiments in which the invention may be practiced. Parenthesized and/or emboldened reference numerals affixed to respective elements merely exemplify the elements by way of example, with which it is not intended to limit the respective elements. It is to be understood that other embodiments may be utilised and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
The present invention generally provides a sorting station comprising multiple compartments for sorting mail items, with the sorting station, in particular each compartment thereof, configured for the capacitive detection of mail items placed in a compartment, as well as a system for sorting mail items comprising at least one or at least two of such sorting stations. The invention also provides a method for sorting mail items, preferably using said sorting station and/or system, comprising the capacitive detection of mail items during sorting, particularly the manual sorting, of said mail items. The primary advantage of the present invention is a significantly reduced occurrence of sorting errors compared to the unaided manual sorting of mail items, particularly as the capacitive detection allows to provide feedback to the person doing the sorting by presenting him with information indicating the correct or incorrect placement of a mail item in a compartment detected by the sorting system/station of the present application. In addition, if a sorting error occurs with the sorting method or station/system of the present invention, the invention also provides a faster, more accurate and reliable error correction. Indeed, despite the small difference in dielectric constant values between air and a mail item, in particular a mail item made from paper, the present inventors have developed an effective method and device to detect mail items during sorting via capacitive detection. The inventors have surprisingly found that the capacitive detection of mail items results in a quick, accurate, sensitive and cost effective detection, resulting in a correct and efficient sorting of the mail items. Additionally, the invention enables a more efficient work flow, thereby achieving a faster sorting speed. Advantageously, the invention is user friendly, particularly for inexperienced operators of the sorting station, due to the possibility of the sorting system/station of the present application indicating in which compartment of the sorting station a mail item needs to be placed and the possibility of verifying the correct sorting, as further detailed below. Furthermore, particular embodiments of the present invention provide a better integration with automated mechanical sorting systems, in particular the merging of the mail sorted via the method and/or station/system of the present invention and the automated mechanically sorted mail items.
An aspect of the invention provides a sorting station for sorting mail items comprising (A) a plurality of detection units, configured for the capacitive detection of a mail item, each detection unit comprising, (Ai) a compartment defining a volume for holding of a mail item; (Aii) at least one capacitive sensor, particularly integrated into one or more walls of the compartment and configured for capacitively sensing the presence or placement of a mail item placed in said compartment, particularly in the holding volume defined by the compartment; and (Aiii) at least one identification means configured for designating or labelling the detection unit or compartment; (B) a control unit connected to the plurality of detection units and configured for registering, managing and/or manipulating a signal provided by the capacitive sensors, such as registering, managing and/or manipulating a change in the capacitance within a detection unit detected by the capacitive sensor, or registering, managing and/or manipulating the presence or placement of a mail item detected by a detection unit when placed in a compartment; and (C) a housing adapted for supporting the plurality of detection units and/or the control unit. In preferred embodiments each detection unit or compartment is configured to minimize interference between the capacitive sensor of said detection unit and the capacitive sensor of a neighbouring, different detection unit/compartment and/or to minimize interference between the capacitive sensor of said detection unit and outside influences, including but not limited to other components of the sorting system of the present invention.
In particularly preferred embodiments, the sorting station for mail items of the present invention comprises: (A) a plurality of detection units, each detection unit comprising (i) a compartment defining a volume for holding a mail item, (ii) at least one capacitive sensor integrated into a wall of the compartment and configured for the capacitive sensing of the placement or removal of a mail item within the holding volume of the compartment, and (iii) at least one identification means configured for designating or labelling the detection unit or compartment; (B) one or more conversion units connected to the plurality of detection units and configured for converting the capacitive signal from each detection unit into a readable, preferably digital, output signal; (C) a control unit connected to the one or more conversion units and configured for registering and/or managing the placement of a mail item in a compartment; and (D) a housing adapted for supporting the plurality of detection units.
The different elements of a sorting station according to the present invention are discussed below.
Advantageously, the sorting station of the present invention is independent of the mail item to be sorted and of the operator performing the (manual) sorting. In principle, any mail item may be sorted by the sorting station of the present invention. In particular, the sorting station is preferably intended for sorting mail items of small or large formats, such as mail items having a length of 140 millimeters (mm) to 360 mm, a height of 90 mm to 230 mm, and a thickness of 0.15 mm to 32 mm. A typical weight of a mail item as envisaged herein is in the range of 2 grams (g) to 2 kilograms (kg). A mail item may have a paper envelope, or may have a wrapper made of plastic or metallic materials, or may occur as a banded bundle. A mail item as envisaged herein may also include small parcels having very heterogeneous dimensions, weights, and packaging with values that can lie outside the range indicated above. For example, it is possible to have small parcels that are 100 mm in thickness and/or 2 kg in weight.
During the sorting process, the mail items as envisaged herein are put or held in a compartment of the sorting station. Each compartment has a volume defined by the boundaries or walls of its enclosure. Since the compartment typically comprises additional features, such as in particular embodiments a capacitive sensor integrated into one or more walls of the compartment, the inner volume effectively available for holding a mail item may be reduced. The volume available for holding a mail item is referred to as the "holding volume" of a compartment. Advantageously, the compartment is adapted for fully holding a mail item, as this may promote the detection of the mail item by the capacitive detector. In an embodiment, the compartment dimensions thus allow for a mail item to be completely surrounded by the boundaries or walls of the compartment. However, in other embodiments, at least a part of the mail item exceeds one or more dimensions of the walls of the compartment or protrudes from the compartment. In general, the present invention allows for the placement or holding of only a single mail item per compartment. However a compartment may also be adapted to allow placement of at least two, for example three, mail items. It is an advantage of the present invention that the capacitive sensor allows distinguishing the placement or presence of a mail item in a compartment when it already contains at least one different mail item.
A compartment as envisaged herein may be a vertical compartment, wherein the height exceeds the width of the compartment (when viewed from the front) and configured for holding a mail item aligned in a vertical direction, or a horizontal compartment, wherein the width exceeds the height of the compartment (when viewed from the front) and configured for holding a mail item aligned in a horizontal direction. Accordingly, in some embodiments the sorting station comprises a plurality of vertical compartments. In some embodiments, the sorting station comprises a plurality of horizontal compartments. In some preferred embodiments, the sorting station comprises a plurality of vertical compartments and a plurality of horizontal compartments. In some embodiments, the vertical compartments have different dimensions and a different holding volume compared to the horizontal compartments. For instance, in Figures 3A and 3B a sorting station with an exemplary arrangement of vertical (indicated by the slots wherein the vertical side walls can be mounted) and horizontal compartments is shown.
In some preferred embodiments, each vertical compartment comprises a height of at least 150 mm to at most 250 mm, preferably 170 to 230 mm, more preferably 190 to 220 mm; most preferably 205 to 215 mm; a width of at least 10 mm to at most 25 mm, preferably 13 to 22 mm, more preferably 15 to 21 mm; most preferably 18 to 20 mm; and a depth of at least 250 mm to at most 450 mm, preferably 300 to 400 mm, more preferably 340 to 370 mm; most preferably 350 to 360 mm. These listed dimensions of vertical compartments are particularly well suited for holding and detection of small to medium-sized mail items, such as letters, magazines, and the like.
In some preferred embodiments, each horizontal compartment comprises a height of at least 20 mm to at most 100 mm, preferably 40 to 80 mm, more preferably 50 to 70 mm; most preferably 55 to 65 mm; a width of at least 200 mm to at most 300 mm, preferably 200 to 280 mm, more preferably 240 to 260 mm; most preferably 245 to 255 mm; and a depth of at least 250 mm to at most 450 mm, preferably 300 to 400 mm, more preferably 340 to 370 mm; most preferably 350 to 360 mm. The listed dimensions of horizontal compartments are particularly well suited for holding and detection of large sized mail items, such as boxes, parcels, and the like.
In some preferred embodiments the sorting station has at least 1 to at most 100 vertical compartments; preferably 10 to 90; more preferably 25 to 75, most preferably 50 to 70, for example 60 compartments. In some preferred embodiments the sorting station has at least 1 to at most 50 horizontal compartments; preferably 2 to 30; more preferably 5 to 15; most preferably 6 to 10, for example 8 compartments. In some more preferred embodiments, the sorting station comprises both vertical and horizontal compartments, i.e. has at least 1 to at most 100 vertical compartments and at least 1 to at most 50 horizontal compartments; preferably 10 to 90 vertical and 2 to 30 horizontal compartments; more preferably 25 to 75 vertical and 5 to 15 horizontal compartments; most preferably 50 to 70 vertical and 6 to 10 horizontal compartments. The listed amounts represent an optimal number of compartments to improve the sorting speed and mail item capacity without making the sorting station too cumbersome or extensive for handling. Furthermore, the arrangement of vertical to horizontal compartments allows a high level of stability.
In the context of the present invention, during the sorting process, a mail item is, preferably manually, placed in and subsequently, preferably manually, removed from a compartment. Accordingly, (manual) accessibility to each compartment must be ensured by providing a suitable opening in each compartment. An example of such an opening may be a slit in the front of the compartment, or may be an, at least partial removal of the front and/or sidewall of said compartment. In preferred embodiments the compartment is an open vertical compartment comprising an L-shaped sidewall, wherein the L-shape is adapted to the size of the mail item, so that both small and large mail items can be detected. In addition, an L-shaped sidewall facilitates repeated placement and removal of a mail item, thus improving the sorting speed.
The present invention is based on the capacitive sensing or detection of a mail item placed in the compartment of a detection unit. In general, a capacitive sensor can sense the presence of any item or material which has a dielectric constant value different from air, and provides a corresponding signal. The main advantages that capacitive sensing has over other detection approaches are that it can sense different kinds of materials (e.g. paper, plastic, metal, etc.), it is a contactless and wear-free detection technique, and it has the ability to sense up to a relatively large distance for small sensor sizes. In addition, a capacitive sensor is able to distinguish between the placement of one versus multiple items in the compartment. This is in contrast to optical (laser) detection means which cannot distinguish between one or more items disrupting the light beam. Additionally, the capacitive sensor requires less maintenance (e.g. cleaning), again in contrast to optical (laser) detection means wherein the presence of particles (e.g. dirt or dust) may hinder the sensing functionality.
The capacitive sensor as used in the present invention is a device with dimensions suitable for integration, i.e. the mountable or non-mountable integration, into a compartment of a detection unit, in particular into one or more walls of the detection unit (or a compartment thereof). In preferred embodiments, the capacitive sensor may be implemented on a printed circuit board (PCB) which in its turn may form a sidewall of a detection unit according to the present invention. The capacitive sensor is configured for a repeatable detection of a mail item: the capacitive sensor senses the change of capacitance in the holding volume of a compartment upon placement of a mail item in a compartment as well as upon removal of said mail item from said compartment. The capacitive sensor in a detection unit according to the present invention thus detects both the placement and the removal of a mail item in or from a compartment.
In preferred embodiments the capacitive sensor comprises a capacitive sensor plate, also referred to as "sensor plate". A typical sensor plate comprises a broad and preferably flat surface which allows for capacitively detecting objects placed between said sensor plate surface and a corresponding ground (plate). The sensor plate and ground plate may comprise a conductive material, such as copper. Generally speaking, the narrower the gap between the sensor plate and the ground the more accurate the capacitive detection can be performed. A sensor plate has the additional advantage that it allows for an easier integration into a sidewall of a compartment, without loss of sensitivity. The ground plate can similarly be integrated into the opposite sidewall of the compartment focusing the capacitive detection area to the inner boundaries of said compartment. In such embodiment, the capacitive detection area is thus limited to the holding volume of said compartment. Advantageously, a sensor plate is low cost, and requires a low operating power, for example, a single electrode capacitive sensor plate. The skilled person understands that the shape of a capacitive sensor plate may depend on the geometry and dimension of the corresponding compartment, or a sidewall thereof.
In preferred embodiments the capacitive sensor also comprises an active shield or guard (coupling) configured for mitigating interference or parasitic capacitances seen along the sensor signal path. The active shielding means thus minimizes noise pickup by the sensor plate due to environmental changes (e.g. mechanical movement, temperature shifts, and humidity changes). In some applications, the parasitic capacitance of the sensor connections can be larger than the capacitance of the sensor, in which case the shielding is necessary. Advantageously, the active shield also helps to focus the sensing area in a specific direction (target). This allows easier calibration of the capacitive sensor. In particular embodiments, the active shield may be a guard plane, comprising a conductive material, such as copper, separating a capacitive sensor from a nearby ground plate of an adjacent compartment. The active shield may also be in the form of a conductive (copper) strip at the edge of a compartment side wall. Preferably, all active shield components are integrated into a compartment sidewall. In some embodiments, the compartment is adapted to function as an active shield though careful choice of materials and design.
In preferred embodiments, the capacitive sensor comprises two or more capacitive sensor plates; each capacitive sensor plate integrated into opposite and/or adjacent sidewalls of the corresponding compartment, for instance implemented in PCBs forming the sidewalls, and arranged so to avoid a parallel and/or lateral overlap of the capacitive detection area. The opposite sidewalls may be the left and right sidewalls or the top and bottom sidewalls; the adjacent sidewalls may be the left and bottom sidewalls, and so on. Integration into opposite sidewalls is, however, more preferred as it helps focus the capacitive detection area. Employing two or more capacitive sensor plates enables the use of multiple, preferably separate, detection channels, thereby generally improving the sensing sensitivity of the detection unit. The more sensor plates are used, the more the detection sensitivity can be improved. However, this simultaneously increases the manufacturing costs of the sorting station. In preferred embodiments, the number of capacitive sensor plates per compartment/detection unit is two or four, allowing for a highly sensitive detection of mail items while still maintaining a reasonable manufacturing price.
In preferred embodiments, the capacitive sensor is implemented on a printed circuit board (PCB), which preferably is used/usable as a sidewall of a detection unit, particularly a vertical detection unit. The sensor plate, guard or shield and ground elements are made up of a conducting material, preferably copper. The PCB typically comprises a protective layer, or a so-called solder mask to protect the sensor elements against oxidation and other environmental influences. Different arrangements of the elements making up the capacitive sensor are possible. For instance, Figure 1B and 1C represents a sensor arrangement suitable for integration into opposite sidewalls, wherein the sensor plate, guard and ground are located in the same plane. Alternatively, Figure 2 represents a stacked layer sensor arrangement on a PCB, suitable as a side wall of a detection unit, wherein the capacitive plate, the guard and ground are located in separate layers. The inventors surprisingly found that a capacitive sensor with a stacked layer arrangement, such as implemented in a PCB, is a surprisingly effective and sensitive sensor with a good signal-to-noise ratio, resulting in an easily measurable/detectable signal change upon placement or removal of a mail item in the detection unit.
In the present invention, the capacitive sensor is preferably integrated into at least one wall of a compartment, preferably a wall adjacent to the frontal opening, such as the left, right, bottom and/or top wall. Preferably, the capacitive sensor is non-dismountably integrated into the wall. By having a non-dismountable integration, such as is the case when the capacitive sensor is implemented in a PCB, the respective parts are intended to stay affixed or connected: the integration is intended to be permanent.
Preferably, if the compartment is a vertical compartment, the capacitive sensor is integrated into the vertical (left and/or) right sidewalls, as this provides the optimal sensitivity for held mail items. A full integration has the additional advantage that the sensor covers the complete holding volume, since it is not limited to the volume occupied by an external measurement device, such as an optical device. In some embodiments the capacitive sensor (plate), such as as implemented in a PCB, may form the sidewall of a vertical compartment. However, to minimise wear of the sensor (plate) a protective layer covering the sensor (plate) surface is advisable. This also facilitates cleaning of the sensor (plate) in case of residue deposits (e.g. glue, stickers) from a held mail item.
In particular embodiments, the capacitive sensor comprises a conversion unit or converter configured to convert the capacitance signal into a readable output signal, allowing further registration, manipulation and/or managing of the signal by a control unit. Preferably, a conversion unit is connected to the plurality of detection units, particularly to the capacitive sensor of each detection unit, via different channels, and configured for converting the capacitive signal from each detection unit, received via a corresponding channel, into a readable output signal. In case more than one conversion unit is present, they may each be connected to a subset of the plurality of detection units, particularly to the capacitive sensor of each detection unit. The output signal may be selected based on the readout method, for instance to voltage or current. A standardized capacitive sensor interface allows for easier and faster read output. Preferably, the output signal is a digital signal to allow easier connection through a digital interface to a control unit (e.g. computer). This is particularly beneficial when connecting multiple capacitive sensor plates and/or multiple sensing channels. The conversion unit may be located distant to the capacitive sensor, but to reduce the effects of parasitic capacitance the conversion unit is preferably located in close proximity to the capacitive sensor. Preferably, the converter is a capacitance-to-digital converter (CDC) chip. The CDC chip provides a flexible solution for interfacing multiple capacitive sensors.
Alternatively, the one or more conversion units may also be comprised in the control unit, the conversion unit thus being connected to the capacitive sensor.
The AD7147 controller from Analog Devices is particular suitable for the purposes of the present invention. This chip is advantageous because it is designed for single electrode capacitance sensors (grounded sensors). It comprises an active shield output to minimize noise pickup in the sensor. It comprises multiple (e.g. 13) programmable sensing (input) channels, for sensing changes in the capacitance of multiple external sensors and uses this information to register a sensor activation. The AD7147 chip is relatively inexpensive and easily configured.
The capacitive mail item detection is preferably threshold based, registering a placement or removal whenever a predefined capacity (voltage) threshold is exceeded. The capacitive sensor may also register the placement or removal of a mail item when there is a change in the signal compared to a baseline signal (e.g. the signal corresponding to an empty compartment, or, particularly the case of the removal of a mail item, the signal corresponding to a compartment holding a mail item. However, there exist many measurement configurations as known by those skilled in the art and the invention is by no means limited to a specific measurement configuration. For example, the measurement accuracy may be improved by making use of algorithms that adapt the threshold value and/or provide a noise reduction by taking into account a derivative (1^st order, 2^nd order, etc.) or an integral (1^st order, 2^nd order, etc.) of the measurement output. The capacitive detection may be time-based, such as a repeated sensing at specific time intervals, or it may be incidence-based, reactivating whenever a sensing parameter is altered, or it may also be configured according to other sensing methods known in the art. The area wherein capacitive detection may occur is referred to as the "capacitive sensing area", and its dimensions (e.g. distance and width) are dependent on the material and operating parameters of the sensor.
When the placement or removal of a mail item is detected by a detection unit, it will be registered by a control unit. Preferably, the control unit is a computer or a computing device which comprises a computer program or computer program product configured to interpret the information received from the detection units. An example of a computing device is a microcontroller. The control unit may comprise additional computer programs or computer program products for operational purposes, including but not limited to computer program products for testing, calibration and debugging of the sorting station, or an alert program that alerts the operator if a detection unit is unresponsive. Advantageously, the control unit allows logging of the sorting station's operations which allows an easy check-up of a placement of a specific mail item.
The connection between the control unit and each of the detection units may be any type of connection which can transfer signals correlated to the detection of a mail item. The signals may be any type such as electrical, optical or electromagnetic (e.g. radio signals). The control unit will manage the identification of the detection units and the registration of the capacitive sensor activation. Preferably a single cable is used. Advantageously, the connection cable also provides the detection units with power for operation. Alternatively, electrical cables may be passed between the control unit and the detection units through the housing, for instance via a pair of mutually aligned slots in the coupling surfaces of the respective detection units. It may further comprise one or more electrical contacts for the passage of signals and/or electrical power.
In some preferred embodiments, a sorting station comprises multiple sub-control units, each connected to at least one detection unit; preferably connected to a set of detection units, for example at least four, or at least six, eight, ten or twelve detection units. Separation of control units allows for more accurate data management, in addition to reduced noise generation. It is also generally less expensive and more straightforward to manufacture. The sub-control units may be further connected to a main control unit that handles all data forwarded from the sub-control units.
In the present invention, the detection unit typically comprises an identification means configured for designating or labelling the compartments. Said identification means is generally a distinctive and unique code attributed to a detection unit. This may be a number, a character or a combination thereof. Preferably, the identification means is displayed on or adjacent to each letter detection unit, for example, it may be a label or a tag affixed to the frontal opening. During the sorting process, as further detailed below, when the operator receives an instruction for placement of a mail item in a certain compartment (detection unit), he can find the designated compartment (detection unit) via the identification means. In some embodiments, each detection unit may be attributed multiple identification means, for instance, an extensive serial number which is used internally by the control unit and a simple location number which is shown to the operator.
In some preferred embodiments, the identification means may comprise an optical source, whereby the control unit is configured for managing the optical source. The optical source as identification means may replace or be in addition to the other identification means described herein. The optical source may include any light source of any color. Preferably, the optical source is a LED, most preferably a multicolor LED. The use of an optical source as an (or one of the) identification means allows for an exceptionally efficient sorting process and error reduction during a sorting process according to the present invention. During sorting, when the operator looks for the designated detection unit, as further detailed below, the control unit will activate the corresponding optical source, thus alerting the operator to the correct compartment and allowing the operator to place the provided mail item in the detection unit designated by the activated optical source. Additionally, the control unit can also activate the optical source of one or more detection units adjacent to or in the vicinity of the designated detection unit in an optically distinguishable manner. Examples of optically distinguishable manners are e.g. activating different colors, when multicolor is available, in particular a first colour for the designated detection unit (e.g. green) and a second, different colour for one or more detection units adjacent to the designated detection unit or for all the other detection units (e.g. yellow); or alternatively, if only a single color is available, enabling blinking at different blinking frequencies, such as a constant light for the designated detection unit and fast blinking lights for adjacent detection units; and so on.
The housing of the sorting station of the present invention typically comprises a rigid chassis in which the different components are mounted. The housing supports the plurality of detection units, and, optionally, also the control unit if said control unit is located within the housing. The housing may also comprise additional protective features, such as shock absorbers. The housing may be made at least partially from any suitable material, having the requisite strength to support the detection units and preferably also being light weight. A suitable material is for instance aluminium.
In some embodiments the housing may be an external housing or chassis, in which case the detection units are mounted in relation to the external housing. Preferably, the housing and the detection units, in particular the compartment walls of the detection units, have a repeatable dismountable connection; i.e. the respective parts are intended for repeatable mutual dismounting and remounting that allows interchangeability: the connection is not intended to be permanent. For instance, the housing may comprise a plurality of gaps or slots, which are configured to engage with rims, lips or protrusions situated on the outside of a compartment or a compartment wall. A dismountable connection allows for easy and fast replacement of a component (compartment, compartment wall) in case of a defective capacitive sensor. Alternatively, the compartments may also have a repeatable dismountable connection with the housing, allowing for a fast modular replacement when a possible failure is detected. The use of modular detection units allows for a quality control and maintenance of the sorting station simultaneous to its use.
In some other embodiments the housing is rigidly attached to the detection units, in which case the detection units may form a structured part of the housing. Preferably, the housing and the detection units have a non-dismountable connection, i.e. the respective parts are intended to stay permanently affixed. The reduction in dismountable connections reduces mechanical instability and long term wear, for instance during movement of the sorting station, and also reduces the requirement for electrical connectors that increase the complexity and weight of the sorting station system in addition to increasing the potential for electronic noise and interference. It is also generally less expensive and more straightforward to manufacture.
The skilled person would appreciate the construction of the sorting station, and in particular that of the housing, has a rectangular form. Although other forms are also compatible with the purposes of the invention, a rectangular form allows an easy placement of mail items and location of the designated detection units without the need to perform unnecessary actions.
Preferably, the sorting station may further comprise a mobile power supply, such as a battery pack. Preferably, a rechargeable mobile power supply is used. Since the capacitive sensors are adjusted for high sensitivity due to the low weight and thickness of certain mail items and the small differences in dielectric constant between the air and the mail items, using a power cable increases the risk of creating interference with the detection units, or with the cables transferring the detection signals to the control unit. Moreover, a mobile power supply also provides a degree of freedom for transporting the sorting station if necessary.
The sorting station may further comprise a transport means to allow handling and transporting of the sorting station. Preferably, the transport means are rigidly affixed to the housing. Examples of transport means are wheels such as trolley wheels, or rails, or tracks, and so on. The transport means may also be a motorised support.
The sorting station may further comprise a wireless networking device configured for wirelessly connecting to a different sorting station, to a central control unit or control station of a sorting system and/or to a database or central server, as discussed in more detail below.
A further aspect of the invention provides a sorting system comprising at least one, preferably at least two sorting stations according to the present invention and a central control unit, with the latter configured for providing and/or presenting instructions to the operator and/or to the one, two or more sorting stations.
The central control unit, also referred to as "central unit" is generally configured for providing an instruction to the operator, in particular to instruct the operator to place a provided mail item in a specific compartment or detection unit of a sorting station and for detecting (sorting) errors made by the operator, for instance by verifying whether the instruction was performed correctly and the mail item was placed in the correct compartment or detection unit. Accordingly, the sorting system further comprises means of presenting instructions to an operator.
The instructions may be provided through a display unit, which is comprised in or is in connection with the central control unit and which is configured for visually displaying an instruction to the operator. This may be a screen or monitor of any type such as CRT, LCD, LED, etc. For example, an operator may receive an instruction to place a provided mail item in a designated detection unit that is additionally or alternatively identified via the corresponding identification means of the designated detection unit. Additionally or alternatively, the sorting system and/or the central unit may comprise an acoustic unit suitable for delivering an audio instruction, such as a (loud)speaker or headphone of any type.
In a most general embodiment, the central control unit is a computer or a computing device which comprises a computer program or computer program product configured to perform at least the following features: (1) establishing a connection with the at least one, two or more sorting stations; (2) determining sorting parameters (e.g. detection unit designation, mail item ordering) based on information with regards to a mail item's parameters (e.g. address, dimensions), particularly wherein such information is received via a suitable input means or mail identification input means, as further detailed below, wherein the sorting action involves designating a detection unit to receive and hold said mail item based on the sorting parameters; (3) providing instructions to the operator, preferably via a display unit, to perform the sorting action; (4) interpreting data received from a sorting station, in particular data with regards to the capacitive detection of a mail item in a detection unit. The combination of the listed features allows the central control unit to effectively function as both a steering device for the mail sorting and as a device for the verification of the correct implementation of the sorting action (i.e. an error checking and correcting device). Similarly to the control units of the sorting stations, the central unit may also comprise additional computer programs or computer program products for operational purposes (e.g. testing, calibration, logging, debugging).
The error checking and correction functionality of the sorting station or sorting system of the present invention can be accomplished in different ways. In a most general embodiment the central unit compares the data received from a sorting station, in particular from the control unit of a sorting station according to the present invention with the sorting instructions previously provided to the operator. Specifically, the central unit will compare the signal of the detection unit that actually received the mail item from the operator with the signal of the detection unit which the central unit has designated to receive the mail item. If the signals received by the central unit do not match, such as they originate from two different detection units, a (human) sorting error will be registered by the central unit. This error can then be reported and presented to the operator, preferably also via the display unit. Advantageously, instructions to resolve the error may subsequently also be provided. Additionally or alternatively, the central unit may use other systems or methods suitable for indicating and/or correcting the sorting error. In preferred embodiments, wherein a sorting station comprises optical sources such as LEDs as an identification means for the detection units, upon registry of an error, an optical source may highlight the compartment (detection unit) that received a misplaced mail item, and, additionally may show the correct detection unit or compartment. The highlighting may include different colorings, blinking frequencies, and the like; for example, the optical source of the compartment erroneously containing a mail item may turn red upon detection of an error, thereby immediately informing the operator and allowing for a fast error correction. Additionally, in case the central unit comprises an acoustic unit, a sound signal may be emitted for an even faster error correction.
Preferably, the central control unit is a component of the sorting system as envisaged herein, independent of the sorting station(s). In some embodiments, the central control unit is a portable computing device, such as a laptop or notebook. In some preferred embodiments the central control unit is a tablet or tablet-like device (e.g. phablet). By keeping the central unit separate from the at least one or two sorting stations, a level of mobility is introduced that may be useful when the operator has to switch between sorting systems. Additionally, it allows for easier maintenance in case of a central unit failure. The central unit may further comprise a wireless networking device configured for wirelessly connecting to a sorting station, a database or central server.
In some embodiments, one of the at least one or two sorting stations comprises the central control unit. The central control unit may be rigidly attached to the sorting station, or comprised within the housing of the central unit. Preferably, the central control unit is slotted into a slot provided in the sorting station, either dismountably or non-dismountably. The central control unit may also be affixed to a structure allowing adjustment of position, such as a support arm or track. Alternatively, the central control unit is comprised in an additional structure with a separate housing, referred to herein as the 'control station'. A control station may be advantageous when the central unit needs to be connected to secondary devices, such as a mail identification unit described below. Preferably, the display unit can also be placed in the control station or in a more centralized location, for instance between the at least two sorting stations, thereby allowing the operator to read the instructions faster. In addition, the control station may comprise all the secondary features present in a sorting station; such as a wireless networking device, a transport means, a mobile power supply, and so on.
In preferred embodiments, the central control unit may further comprise or may be in connection with a means to receive input from the operator, such as a keyboard or touchscreen. Such input means may be used to (manually) adapt the sorting parameters. This can be useful for providing the central control unit with a mail item's delivery parameters (e.g. recipient's name, address) in case of illegible handwriting, wrong letter formatting, and the like. Also, a mail item's dimensional parameters (e.g. size, weight) can be entered this way.
In preferred embodiments, the sorting system may also be configured to connect with a database or a central server. The database or central server may be part of an external platform. The database or central server may be configured to send and receive data from sorting stations and/or systems, and subsequently record said data for administrative purposes; for example to track the location of a mail item. The database or central server may contain at least partial data with regard to a mail item's parameters. This way, the identification and sorting of multiple mail items can be performed even faster and less error-prone. Additionally, it allows for a part of the sorting to be performed beforehand, thereby allowing for a more efficient resource management. Advantageously, when a database error is discovered by an operator, it can be resolved directly from the sorting system and transmitted to the database without the need for redundant actions, such as moving a database or central server access point. The database or central server may also serve as a communication means between different sorting systems and/or methods, for example when manual merging of a mail item with automatically presorted mail items is required.
In preferred embodiments, the sorting system of the present invention comprises a mail identification input unit for identification of a mail item, which is in connection with the central control unit. Indeed, in some embodiments, it is advantageous to use the sorting system for sorting of a mail item for which the mail item's parameters can be automatically obtained, preferably computer aided. For instance, mail items which due to size or content cannot be mechanically sorted may still have readable delivery parameters. Alternatively, the mail items to be manually sorted as envisaged herein may be labelled with a scannable barcode. By having the operator identify a provided mail item's delivery parameters with a mail identification input unit, an increase in sorting speed is achieved, in addition to a reduction of input errors (e.g. typos).
In some embodiments, the mail identification input unit may be configured for a single identification method, for example by only scanning a delivery parameter through barcodes, or be configured for multiple identification methods, for example by scanning barcodes and handwriting. Additionally or alternatively, the identification unit may also identify a mail item's dimensional parameters by determining the size (by scanning) or the weight (by weighing) of the mail item, which would allow an even faster sorting.
The mail identification input unit may be a separate structure, or may be comprised within the sorting system, the central unit or the control station. Preferably, the identification unit is comprised within or on top of a control station. In preferred embodiments, the mail identification input unit comprises a scanner and/or a camera, as known to the skilled person. The scanner and/or camera source may also be external and fixed in relation to the central unit, for example standing on top of the central unit. Typically, a scanner and/or camera includes an optical unit (e.g. optical scanner, laser scanner) or an imaging sensor (e.g. CMOS, CCD). The scanner and/or camera may comprise a lens system for focusing light from the object. A light source such as a laser may be included in the scanner or may be separate. The laser may project a single stripe, multiple stripes that may or may not cross, or form a geometric pattern. The mail identification input unit may also comprise a detector configured for detection a mail item, such as a light or touch sensor. Advantageously, the detector may be configured to automatically activate the mail identification input unit when a mail item is provided by an operator.
The identification of mail items with a scanning unit is known in the art. For instance, for the sorting of mail items according to delivery destination, optical character recognition (OCR) is often used. Typically, first, the position of the name and address of a destination are specified from a scan or an image of the destination field of a postal item. Next, the OCR software identifies the character strings of the name and address. Then, the OCR software performs processing that extracts a sorting code from the character strings in order to sort to each delivery region by referring to a table that associates address character strings and sort codes. Next, the OCR software transmits the processed information to the sorting system that can designate the detection unit to receive the identified mail item. Additionally or alternatively, other mail detection identifying methods are also suitable for the purposes of the invention.
A further aspect of the invention provides a method for sorting mail items via a capacitive based detection of a mail item, preferably in a sorting station according to the present invention, wherein said method comprises the steps of:

(a) providing a mail item;
(b) designating a detection unit (or compartment thereof) to receive the mail item;
(c) placing the mail item in a detection unit (or compartment thereof), preferably manually, thus obtaining a sorted mail item;
(d) capacitively sensing (or detecting) the placement of the mail item in a detection unit;
(e) verifying that the sorted mail item was placed in the detection unit designated in step (b) and registering an error if the sorted mail item was not placed in the designated detection unit (also referred to as an incorrectly sorted mail item), e.g. in a different detection unit than the detection unit designated in step (b);

The method for sorting mail items of the present invention, also referred to as the "sorting method" is generic and independent of the mail item to be sorted. The sorting method as described herein is particularly advantageous for avoiding and, if necessary, correcting (sorting) errors, made by an operator performing a manual sorting, or for avoiding and, if necessary correcting incorrectly sorted mail items, particularly by verifying whether the placement of a mail item in a detection unit was performed correctly. As such, the sorting speed and accuracy is increased through a reduction of the time necessary to perform a correct sorting of mail items. Preferably, the sorting method of the present invention is performed with a sorting system according to the present invention. Because the sorting system may comprise more than one sorting station, for example two, three or four sorting stations, it is to be understood that the sorting method can (in step (b)) designate detection units across different sorting stations.
In some preferred embodiments, step d (capacitively sensing the placement of the mail item in a detection unit, or sensing the change in capacitance in a detection unit upon placement of a mail item in said detection unit) further comprises converting the capacitive signal into a digital signal. Alternatively the conversion may be performed to other readable output signals.
In some embodiments, step (a) of the present method comprises the steps of (a1) providing a mail item; and (a2) identifying the mail item with a mail identification input unit as described herein. As discussed previously, the automatic identification of a mail item provides several advantages, including a reduced error occurrence, improved work-flow and better compatibility with other sorting methods, including automated mechanical sorting (by coordination via a database or central server).
In some embodiments, the present method further comprises displaying instructions or information to the operator, such as on a display unit, such as in step (b) and/or step (e). In particular embodiments, for step (b), the method includes the steps of (b1) designating a detection unit to receive the mail item, for instance based on information received from a central server or database, or from the central control unit; and (b2) displaying or presenting instructions to the operator of the sorting station/system which detection unit is designated. These instructions may be presented to the operator via different means and the invention is by no means limited to a specific display or presentation method of such instructions. Suitable means to present the instructions include but are not limited to displaying on a display unit the identification means of the in b1 designated detection unit or displaying a scheme of the sorting station highlighting the designated detection unit, and so on. In some preferred embodiments of the present method, step (b2) may comprise activating the optical light source of the designated detection unit and, optionally, activating optical sources of the non-designated detection units, such as one or more detection units adjacent to or in the vicinity of the first detection unit in an optically distinguishable manner, such as by using a different colour or blinking. Advantageously, the activation of an optical source allows an operator to easily find the designated detection unit without being overly reliant on the display or the provided instructions.
Similar considerations as discussed for step (b) above regarding the display of instructions or information to the operator are valid for step (e) as well. Accordingly, in particular embodiments, for step (e), the method includes the steps of (e1) verifying that the mail item was placed in the detection unit designated in step (b) and registering an error if the mail item was placed in a detection unit other than the detection unit and (e2) presenting information on the correct or incorrect placement of the mail item, in particular displaying or presenting to the operator of the sorting station/system an error message. In preferred embodiments step (e) may further comprise the step of (e3) if an error is registered in step (e1), displaying or presenting instructions to the operator of the sorting station/system for resolving the error. Such instructions for resolving the error may include the reiteration of the previous instruction for placement (as in step (b2)), or identifying the detection unit that erroneously holds the mail item together with instructions to transfer said mail item to the (correct) first designated detection unit. The sorting method thus provides a faster, more accurate and reliable error correction. Additionally or alternatively, in some embodiments wherein the detection unit comprises an optical source identification means, upon registry of an error, the optical source of the designated detection unit and/or of the (different) detection unit that erroneously received the mail item, can be activated to allow for a faster error correction. In case when two (or more) optical sources activate simultaneously, it is advantageous that the different optical sources are optically distinguishable, for example by emitting a different colour or blinking frequency.
In some embodiments, the present sorting method is adapted for removing one or more sorted mail items from the sorting station, preferably manually, such as in a process of merging the (manually) sorted mail items according to the sorting method of the present invention with other mail items, such as the automatically mechanically sorted mail items. In particular, the present invention further provides a method for removing a sorted mail item from a sorting station or system of the present invention, comprising the steps of:

(a) selecting or designating a sorted mail item;
(b) designating a detection unit that holds the selected sorted mail item;
(c) removing the selected sorted item from the designated detection unit, preferably manually;
(d) capacitively sensing (or detecting) the removal of the sorted mail item from a detection unit, or stated differently, sensing or detecting the change in capacitance in a detection unit upon removal of a sorted mail item;
(e) verifying that the selected sorted mail item was removed from the designated detection unit and registering an error if the selected mail item was not removed from the designated detection unit, e.g. was removed from a different detection unit other than the detection unit designated in step (b);

The preferred embodiments and advantages of the process steps of the sorting method according to the present invention relating to the placement of a mail item in a detection unit are also valid for the process steps of the method for removing or emptying the sorting station, also referred to as the "removing method". Preferably, the removing method is performed on a sorting station and/or system on which previously the sorting method was performed.
In preferred embodiments, the removing method further comprises the step of merging the removed sorted mail item with other sorted mail items, particularly mechanically sorted mail items. Indeed, following sorting, the mail items sorted via different sorting means (manual or mechanical) requires merging in order for an efficient distribution by the mail delivery person.
Thus, in preferred embodiments, the present invention further provides a method for merging different groups of sorted mail items, preferably using the sorting station/system according to the present invention, said method comprising the steps of

(i) sorting mail items to obtain a first group of sorting mail items, via a sorting method of the present invention as described herein;
(ii) providing a second group of sorted mail items; and
(iii) merging the first group of sorted mail items with the second group of sorted mail items, comprising removing a sorted mail item from the first group of sorted mail items and merging with the second group of sorted mail items.

It is understood that the second group of sorted mail items may be sorted by the sorting method of the present invention, or may be sorted via a different sorting method/means. Preferably, said second group of sorting mail items comprises mechanically sorted mail items.
In preferred embodiments, the present invention thus provides a method for merging a first and second group of sorted mail items using the sorting station or system of the present invention, comprising the steps of:

(a) providing a mail item;
(b) designating a detection unit to receive the mail item;
(c) placing the mail item in the designated detection unit, preferably manually, thus obtaining a sorted mail item;
(d) capacitively sensing (or detecting) the placement of the mail item in a detection unit;
(e) verifying that the mail item was placed in the detection unit designated in step (b) and registering an error if the mail item was not placed in the designated detection unit;
(f) repeating steps (a) to (e) for one or more different mail items, thus obtaining a first group of sorted mail items;
(g) providing a second group of sorted mail items;
(h) selecting a sorted mail item from the first group of sorted mail items;
(i) designating a detection unit that holds the selected sorted mail item;
(j) removing the selected sorted mail item from the designated detection unit, preferably manually;
(k) capacitively sensing or detecting the removal of the sorted mail item from the designated detection unit;
(l) verifying that the selected sorted mail item was removed from the designated detection unit and registering an error if the selected sorted mail item was not removed from the designated detection unit;
(m) merging the removed sorted mail item with the second group of sorted mail items. This way, the first and second group of sorted mail items are combined and, advantageously, are fully sorted and ready for delivery.

It is understood that said method for merging a first and second group of sorted mail items combines different embodiments of the sorting mail method of the present invention (i.e. corresponding to steps (a) to (f) of said method for merging a first and second group of sorted mail items, with different embodiments of the removing method of the present invention (i.e. corresponding to steps (h) to (m) of said method for merging a first and second group of sorted mail items). Accordingly, the preferred embodiments and advantages of the sorting method according to the present invention and the removing method as described above are also valid for said method for merging a first and second group of sorted mail items.
A further aspect of the invention provides a sorting station, wherein the station is configured for performing a method according to at least one of the embodiments of the present invention. A further aspect of the invention provides a sorting system, wherein the system is configured for performing a method according to at least one of the embodiments of the present invention.
Another further aspect of the invention provides a computer program or computer program product having instructions which when executed by a computing device or computing device product cause the computing device or computing device product to perform a method according to at least one of the embodiments of the present invention.
A further aspect of the invention relates to the use of a sorting station or sorting system according to an embodiment of the present invention. Preferably, the sorting station or sorting system is used for sorting mail items, as described herein, and/or for removing the sorted mail items, as described herein, and/or for merging the sorted mail items with a second group of sorted mail items.

EXEMPLARY EMBODIMENTS

To better illustrate the properties, advantages and features of the present invention some preferred embodiments are further discussed herein with reference to the enclosed Figures. Accordingly, the present invention discloses many embodiments and adjustments as appreciated by those skilled in the art and the scope of the present invention is by no means limited to one of the illustrative embodiments presented below.

Example 1. Detection unit (100) wherein the capacitive sensor components are located in a single layer.

Figure 1 presents different views of a detection unit (or a plurality of detection units) illustrating a particular capacitive sensor lay-out or setup, i.e. wherein the different components of the capacitive sensor are located in a single plane or layer. Figure 1A depicts an opened illustration of a plurality of detection units (100), particularly vertical detection units (115) as viewed from the front. Figure 1B and 1C show a side view of an opened detection unit (100), illustrating a possible arrangement of the sensor components in a sidewall (105) of a vertical detection unit (115). Figure 1D shows a schematic top view of a plurality of detection units (100).
Each detection unit (100) comprises multiple sidewalls (105) defining a compartment (110) for holding a mail item. In the present example, the sidewalls (105) are L-shaped, but the geometry of the walls is not limited thereto. The distance between each sidewall (105) of a detection unit (100) determines the lateral dimension of a compartment (110). The capacitive sensor (130) is integrated into the sidewall (105) of the compartments (110) and comprises two capacitive sensors plates (135) and two ground plates (136) (Figure 1B and 1C). In addition, each sidewall (105) comprises a suitable shielding or guarding means or element (120) to mitigate potential interference or parasitic capacitances. Figure 1B and 1C show the sensor lay-out of adjacent sidewalls, wherein the capacitive sensor plate (135) of the first sidewall (105) is opposite of a ground plate (136) of a second, adjacent sidewall (105), and vice versa, thus defining a sensing area. This is also depicted in Figure 1A and Figure 1D. Indeed, Figure 1D presents a schematic representation of an arrangement of a plurality of detection units (100) as viewed from the top. The capacitive detection area is represented by the arrows running from every capacitive sensors plate (135) towards the corresponding ground plate (136). This arrangement allows focusing of the capacitive detection area to the inner boundaries of the corresponding compartment (110): the capacitive detection area is thus limited to the holding volume of said compartment (110).
Because the sidewalls between the adjacent compartments are shared, each sidewall thus comprises four capacitive sensors plates (135) and four ground plates (136) (Figure 1D). This setup allows an optimal capacitive sensing of mail items, irrespective of the dimensions of the mail item.
Each detection unit comprises an identification means (140) allowing to distinguish the different detection units (or compartments thereof) during the sorting process. In the present example, the identification mean is a LED, which can be activated to designate a particular compartment/detection unit. Every capacitive sensor plate (135) is connected to a conversion unit (150) configured to convert the capacitance signal into a digital signal. In this exemplary embodiment the conversion unit (150) is an AD7147 CDC chip, which comprises multiple input channels for receiving a signal from multiple sensor plates (135), designated by channel 0 (CH0) to channel 12 (CH12) in Figure 1D). The conversion unit (150) is subsequently connected to a control unit (250) configured for registering the placement of a mail item in the detection unit (100) and further managing of the sorting process. By grouping the capacitive detection data from the four capacitive sensors plates (135) comprised within a single detection unit (100) the control unit can more accurately register the detection of a mail item by a detection unit (100).

Example 2. Detection unit (100) wherein the capacitive sensor has a layer stack layout.

Figure 2 presents different views of a detection unit (or a plurality of detection units) illustrating a particular capacitive sensor lay-out or setup, i.e. wherein the different components of the capacitive sensor are present in different layers or planes of a layer stack setup. Figure 2A shows a side view of an opened detection unit (100), showing how the capacitive sensor (130) is integrated in a sidewall (105). Figure 2B shows a schematic top view of a plurality of detection units (100), wherein the sidewalls (105) separating each compartment have a layer stack setup, as further illustrated in Figure 2C. Different layers of the layer stack are shown in Figure 2D.
As in Example 1, each detection unit (100) comprises multiple sidewalls (105) defining a compartment (110) for holding a mail item. In the present example, the sidewalls (105) are L-shaped, but the geometry of the walls is not limited thereto. The distance between each sidewall (105) of a detection unit (100) determines the lateral dimension of a compartment (110). The capacitive sensor (130) is integrated into the sidewall (105) of the compartments (110). The capacitive sensor (130) has a stacked layer set-up, as shown in Figure 2C, and is integrated in a PCB, which forms the sidewall (105). The ground, shield and sensor plate are made from copper or another suitable conductive material (Figure 2C). The capacitive sensors plate (135), on the outer conductor layer (OC and OC') and adjacent ground plates (136), situated on the inner conductor layer B and B', are separated by a guard plane (120), on the inner conductor layer A and A', that acts as an active shield to mitigate potential interference or parasitic capacitances. The PCB is protected by a suitable protective layer, to protect the sensor during use. Because the sidewalls between the adjacent compartments are shared, each sidewall is constructed symmetrically around a core layer (Figure 2C). The geometry and placement of the different sensor elements within a sidewall are shown in Figure 2D. This stacked layer setup is surprisingly sensitive and effective in sensing a change in capacitance in the compartment.
Figure 2B also presents a circuit diagram illustrating the capacitive sensing channels of an arrangement of a plurality of detection units (100). Similarly, the capacitive detection area is represented by little arrows running from every capacitive sensor between the sidewalls (105). In this exemplary embodiment each sidewall comprises two capacitive sensing channels, one for each side. Each sidewall also comprises two guards forming an active shield (coupling) connected to the ground. Furthermore, to convert the capacitance signal into a digital signal each capacitive sensing channel is connected to a conversion unit; in this exemplary embodiment the conversion unit (150) is an AD7147 CDC chip which comprises multiple input channels for receiving a signal from multiple capacitive sensors, designated by channel 0 (CH0) to channel 12 (CH12). The conversion unit (150) is subsequently connected to a control unit (250) (not shown in Figure 2B) configured for registering the placement of a mail item in the detection unit (100).

Example 3: Sorting station 200) and sorting system (400)

In Figure 3A a schematic illustration of a sorting system (400) is presented, comprising two sorting stations (200) and a central control station or unit (300). The central control station or unit comprises a display unit (310), but alternatively or additionally, the display unit may be located on a sorting station. The sorting stations in Figure 3A and 3B comprise both vertical (115) and horizontal (116) detection units. In Figures 3A and 3B, only a plurality of slots in the housing (190) are shown, wherein the sidewalls of the different detection units can be mounted - the (sidewalls of the) vertical compartments itself are not depicted in Figures 3A and 3B. The sorting system further comprises a scanning means as a mail identification input unit (350), which may be via a wireless or via a fixed connection connected to the central control unit (300).
Figure 3B presents a sorting station (200), carrying a display unit (310), such as a tablet. The tablet is dismountably slotted into a support arm that allows adjustment of the display unit's position relative to the sorting station (200). The sorting station (200) comprises several horizontal compartments (116) and several vertical compartments (115 - as above, only the slots for inserting the vertical sidewalls for forming the vertical compartments are shown). In this exemplary embodiment each horizontal compartment comprises a height of 60 mm, a width of 250 mm and a depth of 355 mm; and each vertical compartment comprises a height of 210 mm, a width of 19 mm and a depth of 355 mm. The sorting station may further comprise a control unit (250) or computer for registering and managing the capacitive detection based sorting process. Additionally or alternatively, this function may be performed by the tablet of the display unit (310): the display unit (310) may thus comprise the control unit (250) of the plurality of detection units of the sorting station or the central control unit (300) of the sorting system.

Claims

A sorting station (200) for mail items comprising:
• a plurality of detection units (100), each detection unit (100) comprising,
o a compartment (110) defining a volume configured for holding a mail item;

o at least one capacitive sensor (130) integrated into a wall (105) of the compartment (110) and configured for capacitively sensing the placement or removal of a mail item placed in the compartment (110); and

oat least one identification means (140) configured for designating or labelling the detection unit (100) or compartment (110);

• a control unit (250) connected to the plurality of detection units (110) and configured for registering the placement or removal of a mail item in or from a compartment (110) of the detection unit (100) by the capacitive sensor (130); and

• a housing (190) adapted for supporting the plurality of detection units (100).
The sorting station (200) according to claim 1, wherein the capacitive sensor (130) comprises two or more capacitive sensor plates (135), each capacitive sensor plate (135) integrated into opposite and/or adjacent sidewalls of the corresponding compartment (110) and arranged to avoid a parallel and/or lateral overlap of the capacitive detection area.
The sorting station (200) according to claim 1, wherein the capacitive sensor (130) integrated in the sidewall (105) has a layer stack setup.
The sorting station (200) according to any of claims 1 to 3, wherein at least one of the detection units (100) comprises
(a) a vertical compartment (115) configured for holding a mail item aligned in a vertical direction, or

(b) a horizontal compartment (116) configured for holding a mail item aligned in a horizontal direction.
The sorting station (200) according to any of claim 1 to 4, wherein the identification means (140) comprises an optical source, preferably a LED, and wherein the control unit (250) is configured for managing and controlling the optical source.
A sorting system (400), comprising
• at least one sorting station (200), preferably at least two sorting stations according to any of claims 1 to 5; and

• a central control unit (300), configured for providing instructions to an operator, preferably via a display unit (310), and/or to the at least one sorting station (200), preferably to the at least two sorting stations (200).
The sorting system (400) according to claim 6, wherein a sorting station (200) comprises the central control unit (300).
The sorting system (400) according to any of claims 6 or 7, wherein the sorting system further comprises a mail identification input unit (350) for identification of a mail item, wherein said mail identification input unit is connected to the central control unit (300) and wherein, preferably, said mail identification input unit comprises a scanner and/or a camera,
A method for sorting mail items in a sorting station (200) according to any of claims 1 to 5, comprising the steps of:
(f) providing a mail item;

(g) designating a detection unit (100) to receive the mail item;

(h) placing the mail item in a detection unit (100), preferably manually;

(i) capacitively sensing the placement of the mail item in a detection unit (100);

(j) verifying that the mail item was placed in the detection unit (100) designated in step (b) and registering an error if the mail item was not placed in the detection unit designated in step (b);
The method according to claim 9, wherein step (b) of the method comprises the steps of:
(b1) designating a detection unit (100) to receive the mail item; and

(b2) displaying or presenting instructions to the operator of the sorting station (200) which detection unit (100) is designated.
The method according to any of claims 9 or 10, wherein the method further comprises activating one or more identification means (140), said identification means being an optical source, for identifying the detection unit (100) designated in step (b) and/or, for informing the operator in case an error is registered in step (e).
The method according to claim 11, wherein the method further comprises activating the identification means (140) of a plurality of detection units (100), adjacent to or in the vicinity of the detection unit (100) designated in step (b), said identification means being an optical source, and said identification means of said plurality of detection units (100) being activated in an optically distinguishable manner, such as a different colour or blinking frequency.
The method according to any of claims 9 to 12, wherein step (a) of the method comprises the steps of (a1) providing a mail item; and (a2) identifying the mail item with a mail identification input unit (350).
The method according to any of claims 9 to 13, wherein the method further comprises (f) repeating the steps (a) to (e) for at least one different mail item and (g) removing the sorted mail items from the sorting station (200), preferably manually.
A method for merging a first group of sorted mail items and a second group of sorted mail items using a sorting station (200) according to claims 1 to 5 comprising the steps of:
(a) sorting mail items via a method according to any of claims 9 to 13, thus obtaining a first group of sorted mail items;

(b) providing a second group of sorted mail items, preferably sorted by automated mechanical means;

(c) merging a mail item of the first group of sorted mail items with the second group of sorted mail items;
wherein step (c) comprises the steps of:
(c1) selecting or designating a sorted mail item from the first group of sorted mail items;

(c2) designating a detection unit (100) that holds the selected sorted mail item of step (c1);

(c3) removing the selected sorted mail item from the designated detection unit (100) of step (c2), preferably manually;

(c4) capacitively sensing the removal of the sorted mail item from the designated detection unit of step (c2);

(c5) verifying that the selected sorted mail item was removed from the designated detection unit (100) of step (c2) and registering an error if the selected mail item was not removed from the designated detection unit (100) of step (c2);

(c6) merging the removed selected sorted mail item with the second group of sorted mail items.