EP3935248B1 - Access control system with a sliding door and visualisation of status information - Google Patents

Description

The invention described here relates to an access control system with a building sliding door and a method for operating the access control system.

Access control systems can be designed in a variety of ways to grant or deny people access to a restricted area. The design can, for example, relate to the way in which people (users) have to identify themselves as being authorized to access, e.g. with a key, a magnetic, chip or RFID card or a mobile electronic device (e.g. mobile phone). WO 2010/112586 A1 describes an access control system in which an authorized user is shown an access code on a display on a mobile phone. If the user holds the mobile phone up to a camera so that it can capture the displayed access code, the access control system grants the user access if the access code is valid.

The design of an access control system can also affect the way in which people are granted or denied access, for example through doors, locks or barriers. For example, it is known that an electronic lock is installed on a door, where an access code must be entered so that the door can be unlocked and opened. In addition to this unlocking function on a door, it is known to monitor the passage through the door. WO 2018/069341 A1 describes, for example, a device that uses sensors to monitor whether and which users are moving through a door. To monitor users using infrared image recording and infrared pulse lighting, the device has a stereometric user recognition device consisting of a radiation source and an image recording device, which is fixed stationary near a wall or door frame. The user recognition device determines the geometric dimensions of a user (person, car) in order to determine how far the door should be opened for the user to pass through. This is intended to increase the comfort and safety of the passing user, for example, a walking or driving person should feel safe when passing through the door. US 2011/227746 A1 also discloses an example of a system for controlling access to a building.

The systems mentioned relate to different access control requirements and the corresponding designs of the access control systems. In addition to these known requirements, there are further requirements, for example the system should be user-friendly without compromising on security requirements. There is therefore a need for a technology for an access control system that meets these requirements, whereby this technology takes into account in particular the aspect of user-friendliness when accessing the restricted access zone.

The invention relates to a system for controlling access to a restricted access zone in a building. The system has a sliding door system and a control device for the sliding door system. The sliding door system has a door frame and a sliding door that can be moved in the door frame between a closed position and an open position by a drive device. The door frame has a passage area and a wall shell area that at least partially accommodates the sliding door in the open position. A control device is arranged on the sliding door and is communicatively connected to the drive device. The control device is designed to control a movement of the sliding door between the closed position and an open position. A light projection device is arranged in an interior of the sliding door and is communicatively connected to the control device. The light projection device is designed to project status information specified by the control device for a user who requests access to the restricted access zone as a visible light projection onto a projection surface.

The invention also relates to a method for operating a system for controlling access to a restricted access zone in a building. The system comprises a sliding door system and a control device for the sliding door system. According to the method, a light projection device is controlled by the control device. The light projection device is arranged in an interior of a sliding door of the sliding door system and is connected to the The light projection device is communicatively connected to the control device. The light projection device is controlled by the control device in order to project status information specified by the control device for a user requesting access as a visible light projection onto a projection surface.

The technology described here creates an access control system that displays status information visible to a user on the sliding door. The status information is projected onto a projection surface by the light projection device. This allows the type and content of the display to be flexibly adapted to a current status or situation. The status information can indicate the status of the system, e.g. the sliding door is locked or unlocked. The status information can also indicate information about the situation or circumstances in the restricted access zone, e.g. that access is not possible or undesirable, that smoking and/or making phone calls are prohibited or that a doctor is in the room for a visit. The user is thus provided with up-to-date and comprehensive information.

According to the invention, the sliding door has an inner door leaf facing the access-restricted zone and an outer door leaf facing away from the access-restricted zone. The interior extends between the inner door leaf and the outer door leaf. The outer door leaf has an operating compartment that extends into the interior and into which the light projection device radiates the light projection. Since the operating compartment extends inwards, it does not protrude from the plane of the outer door leaf and thus does not interfere when moving into the wall shell area.

In one embodiment, the projection surface is arranged in the control compartment and extends between the inner door leaf and the outer door leaf, so that the projected status information is visible to the user requesting access. One advantage of projecting onto the projection surface in the control compartment is that the light projection is less exposed to potentially disruptive ambient light and is therefore more visible.

Alternatively or additionally, the light projection device can be arranged in one embodiment such that the status information is projected onto a floor area in front of the sliding door. This results in a larger projection surface. Regardless of where the status information is projected, one or more colors or lighting effects can be selected, for example to draw the user's attention to the status information. The expert recognizes that the projected status information can be supplemented by a voice message if required.

In one embodiment, the light projection device is designed to project an input field onto the projection surface. In this embodiment, the light projection device is designed similarly to a virtual keyboard projected by laser light. An evaluation program detects coordinates of the finger movements and assigns them to corresponding keys and/or symbols.

In another embodiment, a detection device can be present which is arranged on the sliding door and is communicatively connected to the control device. The detection device detects a manual interruption of the projected status information. This makes it possible to recognize a conscious action by the user which the user must perform in one embodiment in order to express his actual intention to gain access. This makes it possible to ensure that the sliding door only opens when there is an intention to gain access.

According to one embodiment, the detection device comprises a light barrier. In this embodiment, fingers or a hand can interrupt the light path between a light source and a light receiver, for example when the user follows a request (e.g. projected text "Please touch").

In addition to detecting the actual intention to access, the system, according to one embodiment, enables a check to be made as to whether the user is authorized to access. For this purpose, the system is provided with at least one detection device that is arranged on the sliding door system or in its vicinity and is communicatively connected to the control device. If the user is authorized to access, the control device causes the sliding door to move.

In one embodiment, the detection device comprises a Camera device that carries out a facial recognition process. There is an opening in the outer door leaf, behind which a camera of the camera device is arranged in the interior of the sliding door. The opening has a small diameter of a few millimeters and is therefore barely noticeable. As an alternative to facial recognition or in addition, the recognition device according to one embodiment comprises a radio device that records and checks proof of authorization presented by the user. Neither the facial recognition-based check nor the radio-based check require the user to touch the sliding door.

These options for checking access authorization allow access control to be individually adapted to the conditions in the building. In the case of radio-based checking, several alternatives are also possible, for example Bluetooth technology or RFID technology can be used. For increased security requirements, for example, both facial recognition and the checking of proof of authorization can be provided.

In one embodiment, the detection device is designed to generate a status signal when the user requests access. The status signal is thus generated as soon as a user is present. In one embodiment, the status signal can be used, if necessary, to activate the light projection device by the control device, e.g. from a standby mode to an active operating mode. If no user is present, the light projection device can be switched off or in standby mode, e.g. to minimize energy consumption.

Another advantage of the technology described here is that its use is not limited to a specific type of sliding door system. In one embodiment, the sliding door can comprise an actuator that is designed to position the door leaves in the closed position of the sliding door in a first position with a first leaf spacing and in the open position of the sliding door in a second position with a second leaf spacing. The first leaf spacing is greater than the second leaf spacing.

Fig. 1

eine schematische Darstellung einer beispielhaften Situation in einem Gebäude mit einem Zugangskontrollsystem gemäss einem Ausführungsbeispiel;

Fig. 2A

eine schematische Darstellung eines beispielhaften Schiebetürsystems mit einer geschlossenen Schiebetür;

Fig. 2B

eine schematische Darstellung des Schiebetürsystems aus Fig. 2A, wobei die Schiebetür in einer Zwischenposition ist;

Fig. 2C

eine schematische Darstellung des Schiebetürsystems aus Fig. 2A, wobei die Schiebetür in einer offenen Position ist;

Fig. 3

eine schematische Darstellung eines Ausführungsbeispiels einer Lichtprojektionseinrichtung einer Schiebetür, die im in Fig. 1 gezeigten Ausführungsbeispiel eines Zugangskontrollsystems verwendet wird;

Fig. 4

schematische Darstellungen von beispielhaften Piktogrammen, die von der in Fig. 3 gezeigten Lichtprojektionseinrichtung erzeugt werden können;

Fig. 5

eine schematische Darstellung eines Ausführungsbeispiels einer Aktivierungseinrichtung einer Schiebetür, die im in Fig. 1 gezeigten Ausführungsbeispiel eines Zugangskontrollsystems verwendet wird;

Fig. 6

eine schematische Darstellung eines Ausführungsbeispiels einer Steuereinrichtung für das in Fig. 1 gezeigte Zugangskontrollsystem; und

Fig. 7

ein Ablaufdiagram eines Ausführungsbeispiels eines Verfahrens zum Betreiben eines Zugangskontrollsystems.

Below are various Embodiments of the invention are explained in more detail in conjunction with the figures. In the figures, the same elements have the same reference numerals. They show:

Fig.1

a schematic representation of an exemplary situation in a building with an access control system according to an embodiment;

Fig. 2A

a schematic representation of an exemplary sliding door system with a closed sliding door;

Fig. 2B

a schematic representation of the sliding door system Fig. 2A , the sliding door being in an intermediate position;

Fig. 2C

a schematic representation of the sliding door system Fig. 2A , with the sliding door in an open position;

Fig.3

a schematic representation of an embodiment of a light projection device of a sliding door, which in Fig.1 shown embodiment of an access control system;

Fig.4

schematic representations of exemplary pictograms used by the Fig. 3 shown light projection device;

Fig.5

a schematic representation of an embodiment of an activation device of a sliding door, which in Fig.1 shown embodiment of an access control system;

Fig.6

a schematic representation of an embodiment of a control device for the Fig.1 access control system shown; and

Fig.7

a flow chart of an embodiment of a method for operating an access control system.

Fig.1 is a schematic representation of an exemplary situation in a building with an access control system 1 comprising a sliding door system 5 and a control device 8 (DC) controlling the sliding door system 5. The sliding door system 5 is inserted into a building wall and represents a physical barrier between a public zone 21 and an access-restricted zone 22. With reference to the Fig.1 In the xyz coordinate system shown, the building wall extends in a plane that is spanned by the x and z axes. The access-restricted zone 22 can be, for example, an apartment, a business premises or another room in a building. The sliding door system 5 can be integrated into an interior building wall (for internal access control, e.g. access to an apartment) or into a The sliding door system 5 may be inserted into the building's exterior wall (for controlling access to the building). As explained in more detail elsewhere in this description, the sliding door system 5 opens a sliding door 4 for an authorized user 20, while it remains closed for a non-authorized user 20. The term "building" in this description includes, for example, residential and/or commercial buildings, hospitals, sports arenas, airports and ships.

In the Fig.1 In the situation shown, embodiments of the technology described here can be used in an advantageous manner to operate the access control system 1 with the highest possible degree of security, whereby the user 20 can still be granted comfortable access to the restricted access zone 22. In addition, the technology described here allows the user 20 to display flexible and up-to-date visible status information. The status information can provide information on the situation or conditions in the restricted access zone 22, e.g. that access is not possible or undesirable. The status information is projected onto a projection surface 27, 27a by a light projection device 13. The light projection device 13 is arranged on the sliding door 4 and moves with it when the sliding door 4 is moved.

This in Fig.1 The sliding door system 5 shown comprises a door frame 2 (also referred to as a door casing) and the sliding door 4. The door frame 2 has a passage area 24 and a wall shell area 18 which is designed to at least partially accommodate the sliding door 4. The wall shell area 18 has a structure which forms a cavity which is dimensioned to accommodate the sliding door 4. The passage area 24 is the area in the building wall in which a passage along the y-axis from one zone (21, 22) to the other zone (21, 22) is possible; it exists between a vertical frame part 2a (door post) and the opposite wall shell area 18. Depending on the design, the wall shell area 18 is accommodated in a cavity in the building wall or the wall shell area 18 can be regarded as part of the building wall, possibly after cladding.

The sliding door 4 is in the door frame 2 between a Fig. 2A shown closed position and one in Fig. 2C shown open position. Related to the in Fig.1 The xyz coordinate system shown is used to move the Sliding door 4 along the x-axis. In the Fig. 2C In the open position shown, the sliding door 4 is located in one embodiment essentially within the wall shell area 18. Between these maximum positions, the sliding door 4 can have a Fig. 1 and Fig. 2B shown intermediate position, in which the sliding door 4 (and correspondingly the passage area 24) is more or less wide open, ie a front side 30 of the sliding door 4 has a variable distance from the frame part 2a. In Fig. 2B This variable distance is shown as opening width W.

The sliding door 4 has two essentially parallel door leaves 26, each on an inner side and an outer side of the sliding door 4. The inner side of the sliding door 4 faces the restricted access zone 22, and the outer side of the sliding door 4 faces the public zone 21. Accordingly, the door leaf 26 on the inside is referred to as the inner door leaf 26 and that on the outside as the outer door leaf 26. The door leaves 26 are spaced apart from one another (in the y-direction) so that there is an interior space between the door leaves 26 in which system components and, if required, insulation material for sound and fire protection can be arranged. The door leaves 26 are connected to one another in the area of the front side 30, as for example in Fig. 2A Each of the door leaves 26 extends substantially parallel to the xz plane.

In addition to the aforementioned control device 8 and activation device 19, Fig.1 a recognition device 14, an interface device 7, a sensor device 10, a camera device 3 for facial recognition, a light projection device 13, a detection device 17 and a drive device 6 (M), which in one embodiment are components of the sliding door system 5. In the following, embodiments are described with reference to the Fig.1 shown access control system 1 and its system components. The person skilled in the art will recognize that one or more of these system components may be optional; ie, depending on the requirements in the building, for example, the light projection device 23 and/or the activation device 19 may be omitted. Instead, alternative devices may be used, e.g. optoelectronic displays, electromechanical displays, door handles or door key systems. For example, in one embodiment, an activation device 19 may be present, but no light projection device 23. If in this embodiment a display of If information is required, a display can be provided for this purpose. The expert will recognize that this applies analogously to other system components.

In one embodiment, the sliding door system 5 is connected to a building management system 12 (BM); in Fig.1 In the embodiment shown, this connection is made by means of a communications network 28 to which the building management system 12 and the interface device 7 are coupled. The person skilled in the art will recognize that the building management system 12 can be outsourced in whole or in part to an IT infrastructure for so-called cloud computing (also colloquially referred to as "cloud"). This includes, for example, the storage of data in a remote data center, but also the execution of programs that are not installed locally but remotely. Depending on the design, a certain functionality can be made available, for example, in the control device 8 or via the "cloud". For this purpose, for example, a software application or program parts thereof can be executed in the "cloud". The control device 8 then accesses this infrastructure via the interface device 7 as required in order to execute the software application.

The communication network 28 can comprise an electronic bus system in one embodiment. In one embodiment, the electrical connection of the sliding door system 5, including its supply with electrical energy, is made via the interface device 7. The person skilled in the art will recognize that several sliding door systems 5 can be present in the building and that each of these sliding door systems 5 is coupled to the communication network 28 in order to communicate with the building management system 12, for example in connection with determining and checking access authorizations if these are carried out centrally by the building management system 12.

The control device 8 is connected to the sensor device 10 by an electrical connection 32. The control device 8 is also connected to the drive device 6 and the interface device 7 by means of an electrical connection 34. The electrical connections 32, 34 are designed for signal and/or energy transmission; for this purpose, they can each comprise individual electrical lines or an electrical bus system.

The control device 8 is also connected to the camera device 3 and the recognition device 14. With the help of the camera device 3 and/or the recognition device 14, it can be determined in one embodiment whether the user 20 is authorized to gain access to the restricted access zone 22. If the determination shows that the user 20 is authorized to gain access, the control device 8 causes the sliding door 4 to open. The expert recognizes that, depending on the requirements in the building, both or only one of the aforementioned devices (camera device 3, recognition device 14) can be present in the access control system 1.

The camera device 3 comprises a camera, e.g. a digital camera, a storage device and an image processing module. The image processing module is configured to carry out a computer-aided method for image processing. Image processing methods are known, for example from US8,494,231 B2 A basic description of image processing for the purpose of facial recognition is described in the publication "Facial Recognition" by the German Federal Office for Information Security (available under the topic of biometrics at the Internet address www.bsi.bund.de). This publication distinguishes between the three main work steps "Create template", "Create reference data set" and "Compare facial images". In order to keep the comparison of two facial images as simple and quick as possible, the features of a face are determined and saved in the form of a feature data set known as a "template". Once the face has been found and normalized in a user's image, other features in addition to the eyes, nose and mouth/chin area are searched for, measured and related to each other. These extracted features are coded, compressed and saved as a feature data set (template). In order to determine the similarity of the templates of two facial images, they are combined using a mathematical algorithm. This results in a degree of similarity of the templates. If the result is within certain tolerance limits, the two templates, and thus the facial images on which they are based, are classified as identical.

Various situations can arise at the sliding door system 5; the user 20 may want to enter the restricted access zone 22 or leave it. In an example situation, the user 20 is in the public zone 21 and approaches the sliding door 4 to enter the access-restricted zone 22. In one embodiment, the approach activates the camera device 3, which then determines a facial template from an image of the user 20 and compares it with stored templates of users with access authorization. The person skilled in the art will recognize that the image can be displayed on a display device (e.g. video monitor), for example in connection with a (video) door intercom system, in the access-restricted zone 22. Depending on the design, the image can also be stored.

The person skilled in the art will recognize that the camera device 3 can also be designed to capture other biometric features (e.g. iris/retina pattern, fingerprint pattern).

The recognition device 14 is designed to record an authorization proof from the user 20, on the basis of which the access control system 1 can determine the access authorization of the user 20. The authorization proof can, for example, be in the form of a physical key, a manually entered password (e.g. a PIN code), a biometric feature (e.g. fingerprint, iris pattern, speech/voice characteristics) or an access code recorded by a magnetic, chip or RFID card or an electronic device (NFC, Bluetooth or mobile phone based). The user 20 presents the authorization proof if he wishes to access the restricted access zone 22.

Depending on the forms that the proof of authorization can take, the proof of authorization can be presented in different ways, for example by a conscious manual action (e.g. entering a PIN code or holding up an RFID card) or by approaching the door in order to get within radio range of the recognition device 14 (e.g. to establish a Bluetooth connection). The recognition device 14 can be arranged on the sliding door 4, on the door frame 2 or in its surroundings; for example, it can be arranged in the interior of the sliding door 4 so that it can record the proof of authorization when the user 20 is in the public zone 21.

The recognition device 14 is designed according to the authorization proof provided in the access control system 1. This means that the recognition device 14 has, for example, a door cylinder, a recording device for a biometric feature, a recording device for an optical code, a reader for a magnetic stripe card or a chip card, a keyboard or a touch-sensitive screen for manually entering a password, a transmitting and receiving device for radio signals. The person skilled in the art will recognize that in one embodiment the sliding door system 5 can have more than one recognition device 14, each for a different type of authorization proof, or that one recognition device 14 is designed for several types of authorization proof.

The person skilled in the art will also recognize that a detection device 14 arranged on the sliding door 4 is designed or arranged in such a way that the sliding door 4 can be moved into the wall shell area 18. The detection device 14 can be arranged in the interior of the sliding door 4 for this purpose; it can also be arranged in the area of the front side 30 if this area does not extend into the wall shell area 18 in the open position.

In Fig.1 In the embodiment shown, the recognition device 14 detects an authorization certificate that a radio device 37 carried by the user 20 transmits as a radio signal. The radio signal can be transmitted according to a known standard for radio communication (e.g. RFID, WLAN/WiFi, NFC, Bluetooth). Accordingly, the recognition device 14 is designed to receive such a radio signal; in Fig.1 A transmitting/receiving device 16 and an antenna connected to it are shown for this purpose. The expert will recognize that when using radio signals, the door leaves 26 are permeable to them.

The transmitting/receiving device 16, alone or in conjunction with the control device 8, determines the authorization proof from the received radio signal, which is then used to determine the access authorization. If the authorization proof is valid, the user 20 can be granted access. If the authorization proof is not valid, access is denied and the sliding door 4 is closed.

Depending on whether the user 20 is authorized to access the system or not, this can be communicated to the user 20 by means of corresponding status information 23 in one embodiment. In one embodiment, the status information is communicated by the light projection device 13, which projects the status information 23 onto a projection surface. As in Fig.1 and Fig.3 As indicated, the projection surface can be provided on the sliding door 4; alternatively or additionally, the projection surface can be a floor surface (in the public zone 21) in front of the sliding door 4. As in Fig.4 As indicated, the status information 23 can be represented by one or more pictograms 23a, for example by a closed or opened padlock. Further details on the light projection device 13 are provided in connection with Fig. 3 and Fig. 4 disclosed.

In one embodiment, the sliding door 4 does not open immediately after the user 20 is recognized as having access authorization by means of the camera device 3 and/or the recognition device 14. Depending on the building situation, it may not be desirable, for example, for the sliding door 4 to open if the user 20 is recognized as having access authorization but does not currently wish to gain access but is merely walking past the sliding door 4. Such a situation may arise, for example, in a building corridor with a number of adjacent rooms (e.g. offices, hospital rooms); the user 20 (e.g. supervisor, doctor) may in principle be authorized to access all rooms, but at a certain point in time the user 20 may actually only wish to have access to one of these rooms.

The detection device 17 serves to recognize such an intention; in one embodiment, the intention can be expressed by the user 20 having to perform a conscious action, for example, having to move very close to the sliding door 4 or having to stretch out a hand. As in Fig.1 As indicated, the detection device 17 in one embodiment comprises an optical detection device that detects the conscious action. The detection device 17 detects, for example, that the user 20 is extending his hand. In one embodiment, the detection device 17 comprises a light barrier that is designed such that the hand interrupts a light path between a light source and a light receiver. Further details according to a Embodiment of the detection device 17 are in connection with Fig.3 disclosed.

The person skilled in the art will recognize that, as an alternative to a light barrier, the detection device 17 can have a sensor based on a different principle, for example a laser scanner, a camera, a radar sensor, a capacitive sensor, a time-of-flight sensor or the like.

Fig.3 shows a schematic representation of an embodiment of the light projection device 13, which in Fig.1 shown embodiment of the access control system 1. A part of the sliding door 4 is shown in cross section (yz plane), showing the outer door leaf 26 (left) and the inner door leaf 26 (right) and the interior space in between. The location of the user 20 is indicated by an eye, with the user 20 looking at an operating compartment 25 which is provided on the outer door leaf 26. In the shown embodiment, the operating compartment 25 is formed by a cutout in the outer door leaf 26 and extends into the interior of the sliding door 4. In the operating compartment 25 there is a projection surface 27 which is arranged obliquely in the vertical direction, for example it extends obliquely upwards from the perspective of the user 20.

As in Fig.3 As indicated, the light projection device 13 is arranged in the interior above the projection surface 27. From there, the status information 23 is projected onto the projection surface 27 and is visible to the user 20. An example light path is indicated by a downward arrow and a horizontal arrow pointing outwards. In Fig.3 It is also indicated that the status information 23 can be projected onto the floor (in the public zone 21) in front of the sliding door 4. In one embodiment, the light projection device 13 comprises a laser scanner which projects the status information 23 onto the projection surface 27 using laser radiation. Such laser scanners are commercially available, e.g. a micro scanner from Bosch Sensortec GmbH, Germany.

In one embodiment, the light projection device 13 is designed to project an input field onto the projection surface 27, 27a. The input field can comprise, for example, a keyboard and/or symbols on which the user 20 can, for example, a PIN code or a symbol (e.g. a key symbol for unlocking or locking) can be entered or selected. In this embodiment, the light projection device 13 is designed similarly to a known device which allows, for example, a computer keyboard or a piano keyboard to be projected onto a surface. In such a device, a laser projects the keyboard and a camera detects the finger movements. An evaluation program detects coordinates of the finger movements and assigns them to corresponding keys and/or symbols. A device for optically entering commands is, for example, in EP 0 554492 A1 disclosed.

A light projection device 13 designed in this way allows the action of the user 20 to be determined based on the "touched" field (key or symbol). A separate detection device 17 may not be required. Accordingly, a field can also be "touched" if the input field is projected onto the floor in front of the sliding door 4; the "touching" can be done with a foot, for example.

As mentioned above, the status information 23 can be represented by pictograms 23a, symbols and/or text. Fig.4 shows exemplary pictograms 23a; from left to right, these indicate that the sliding door 4 is locked, that the sliding door 4 is unlocked, that certain actions are undesirable or prohibited (e.g. smoking or making phone calls) and that access is not permitted. In one embodiment, a pictogram 23a or symbol can be supplemented by text; the text can be an instruction, for example (e.g. "Please touch", "Please wait", "No access", "Do not disturb" or similar). The name of the user 20 can also be displayed as text, for example. In addition to a pictogram 23a, in one embodiment, an audible signal and/or a voice message corresponding to the pictogram 23a can be triggered.

The size of the cutout or the operating compartment 25 is selected such that the status information 23 can be displayed in a sufficient size to be recognized by the user 20 when he is in front of the sliding door 4. In one embodiment, the size of the cutout is also selected such that the user 20 can hold a hand or one or more fingers in if he wants access.

Depending on the area of application, the control compartment 25 can be designed to be vandal-proof. If the control compartment 25 is designed in the same way as the rest of the door leaf 26, e.g. in the same color and/or color pattern, the control compartment 25 blends in visually with the door leaf 26; particularly when the light projection device 23 is switched off, the control compartment 25 is therefore inconspicuous and unobtrusive and therefore of no interest to vandals. The control compartment 25 can be embedded in the material of the door leaf 26 (in one piece). An opening in the direction of the light projection device 23 can be closed with bulletproof glass in order to protect the light projection device 23 from damage. The control compartment 25 can also be easily cleaned, particularly when it is in a one-piece design.

In one embodiment, the control compartment 25 may be protected by a cover or closure mechanism. The cover or closure mechanism may, for example, comprise an actuator and a flap or cover; for example, the flap or cover closes the control compartment 25 and thereby prevents a hand or an object from being inserted into the control compartment 25. The actuator may unlock and/or open the flap or cover as needed to allow the control compartment 25 to be used.

The detection device 17 is in Fig.3 also shown. In the embodiment shown, the detection device 17 is arranged such that the fingers of the user 20 held in interrupt the light path of the light barrier. In one embodiment, the light barrier is arranged on vertical side parts inside the operating compartment 25; in this case, the light path of the light barrier extends from the perspective of the user 20 between a vertical left side part and a vertical right side part. The person skilled in the art will recognize that the light barrier can consist of more than one light source/light receiver pair. The person skilled in the art will also recognize that in one embodiment, the detection device 17 can comprise a non-optical detection device (e.g. a proximity sensor).

Fig.5 shows a schematic representation of an embodiment of the activation device 19, which is connected directly to the control device 8. The activation device 19 comprises a proximity sensor 54, 56 and a processing device 58 connected thereto, which is communicatively connected to the control device 8 is connected. The proximity sensor 54, 56 comprises a (first) conductive field plate 54 and an evaluation device 56 (ΔE) which is connected to the processing device 58. The conductive field plate 54 is, in one embodiment, a copper plate which is arranged in the interior on the inner door leaf 26. In this embodiment of the activation device 19, the field plate 54 and the evaluation device 56 form a capacitive sensor, the field plate 54 representing an electrode of an open capacitor. An electric field emanates from the electrode. If a material (the user 20) with a dielectric constant greater than air penetrates the electric field, the capacitance of the field changes as a function of the penetration depth, depending on the dielectric constant of this material. The evaluation device 56 measures this change in capacitance, and a resulting detection signal DS is evaluated in the subsequent signal processing by the processing device 58.

The signal processing compares, for example, the resulting detection signal DS with a specified reference signal. The reference signal is used to determine the penetration depth (i.e., the proximity of the user 20) at which the sliding door 4 is to be opened. In one embodiment, the resulting detection signal DS has a value that is higher the closer the user 20 or a body part (e.g., hand) is to the sliding door 4. If the value of the detection signal DS exceeds a value specified by the reference signal, i.e., the user 20 is "close," the processing device 58 generates the activation signal AS. The control device 8 then causes the sliding door 4 to move.

The person skilled in the art will recognize that a (second) conductive field plate 60 can be arranged as in Fig.5 shown. In conjunction with the evaluation device 56, the field plate 60 forms a (second) proximity sensor in an analogous manner, which is also a capacitive sensor. In one embodiment, the conductive field plate 60 is also a copper plate, which is arranged in the interior on the inner door leaf 26. The evaluation device 56 can, for example, have a signal input (port) for each field plate 54, 60 in order to determine the capacitance changes that can be measured with it. Depending on the design, the evaluation device 56 can have one or two (or more) separate signal outputs for the detection signal(s) DS. The processing device 58 is designed to process at least one of the detection signals DS.

This results in different applications: The field plates 54, 60 of these capacitive sensors can be arranged at different heights on an inner side of the inner door leaf 26. A lower field plate 54, 60 can, for example, be provided to detect the approach of a pet (cat, dog) so that the sliding door 4 is opened for the pet, whereby the opening width can be fixed for the pet. The person skilled in the art recognizes that in one embodiment the pet can also be equipped with an RFID transponder. In order to open the sliding door 4, for example, the identifier of the RFID transponder must be recognized and the pet must be close to the lower field plate 54, 60.

The capacitive sensors formed by the field plates 54, 60 arranged in this way can be activated for use individually, i.e. one of the capacitive sensors can be used or both. For example, if the user 20 does not have a pet but has a small child, only the upper capacitive sensor can be activated for safety reasons. Activation can be achieved, for example, by only connecting the upper field plate 54, 60 to the evaluation device 56. Alternatively, the lower field plate 54, 60 can also be connected to the evaluation device 56, but the evaluation device 56 is designed (programmed) not to process the associated detection signal DS. In one embodiment, the evaluation device 56 can be programmed such that the detection signal DS associated with the lower field plate 54, 60 is only processed during a certain period of time, e.g. during a period of time during which the pet is allowed to leave the apartment.

In another application, the field plates 54, 60 of these capacitive sensors can be arranged essentially horizontally next to one another at a fixed distance on the inside of the inner door leaf 26. By means of the capacitive sensors formed by the field plates 54, 60 arranged in this way, the processing device 58 can, for example, detect a direction of movement of the user 20 or a body part (e.g. hand). For this purpose, the processing device 58 determines, for example, a temporal sequence of generated detection signals DS. If the movement occurs, for example, from left to right, first the electric field of the field plate 54, 60 arranged on the left changes and then the electric field of the field plate 54, 60 arranged on the right. The temporal sequence results from these field changes. the detection signals DS. A hand movement from left to right can, for example, cause the sliding door 4 to open.

In a further embodiment, several field plates can be arranged, for example, in a pattern of rows and columns, similar to a matrix, for example in the form of a 2 x 2, 3 x 3 or 3 x 4 matrix. The person skilled in the art will recognize that other arrangements are also possible. Each of these field plates generates a detection signal DS when the hand is in its vicinity. By evaluating the temporal sequence of the detection signals DS, a gesture can be recognized.

In the following, further functionalities of the access control system 1 are described as examples. Fig.1 The sensor device 10 shown is arranged in an area of the front side 30 of the sliding door 4, for example in an area of an upper (corner) edge of the sliding door 4. From this raised area, the sensor device 10 has an optimized detection field 11 in the direction of the passage area 24 and the floor. An exemplary detection field 11 is shown in Fig.1 (vertical) and in Fig. 2B (horizontal). The person skilled in the art will recognize that the horizontal detection field 11 is Fig. 2B shown form may differ, for example may be narrower. In addition, the sensor device 10 is better protected against dirt and damage (e.g. due to vandalism) in this (upper) area.

According to one embodiment of the invention, the sensor device 10 is used to detect a gesture that the user 20 performs when he wants to change the opening width W. A change may be desired because the user 20 requires a larger opening width, for example if he is carrying one or more larger objects (e.g. package, suitcase) or if he is temporarily using an aid for mobility (e.g. wheelchair). The technology described here offers the user 20 the possibility of changing the opening width if necessary, in particular of increasing it. In another embodiment of the technology, the opening width is selected and stored such that the sliding door 4 initially only opens a crack. The crack is so narrow that the user 20 cannot pass through. The opening width (crack width) can also be selected such that the user 20, who is located at the sliding door 4, is in the detection field 11 of the Sensor device 10 is located and the sensor device 10 can detect a gesture of the user 20. If the user 20 then carries out a specified gesture, the sliding door 4 opens according to a specified opening width and the user 20 can pass.

The gesture may, for example, comprise a movement of the body and/or a body part, for example a movement of the head, an arm, a hand, a leg or a foot. The movement may be directed, e.g. left, right, up, down, or it may comprise combinations thereof. The person skilled in the art will recognize that another type of gesture may also be defined, e.g. one or more signs (e.g. hand and/or finger signs) or a sequence of such signs. The gesture may be defined individually for the user 20 or for a group of users (e.g. family members or employees of a company).

In one embodiment, the sliding door system 5 can be designed to move the sliding door 4 piece by piece, for example depending on certain gestures. A movement in the direction of the wall shell area 18 opens the sliding door 4 a little. A movement in the direction of the door post 2a closes it a little again. In addition, a quickly executed movement can cause the sliding door 4 to open or close completely.

Using the sensor device 10, a (vertical) height of the user 20 can also be determined in one embodiment. In the present description, the term "height" is used for the extension of the user 20 in the direction of the z-axis, although the size of people is usually specified. The height of the user 20 indicates a distance between the floor and a topmost point or area of the user 20. At the time of determination (measurement time), the user 20 is on the floor essentially in the passage area 24. The sensor device 10 has a fixed and known distance from the floor (floor distance). In this situation, according to one embodiment, a user distance between the sensor device 10 and the user 20 is determined. The height H of the user 20 results from a difference between the floor distance and the user distance.

In one embodiment, the sensor device 10 comprises at least one 3D camera. Those skilled in the art will recognize that the sensor device 10 can have more than one 3D camera and/or at least one additional sensor based on a different measuring principle. A camera based on the principle of time of flight (TOF sensor) measurement can be used as a 3D camera. The 3D camera comprises a light-emitting diode or laser diode device that emits light in the infrared range, for example, with the light being emitted in short pulses (e.g. several tens of nanoseconds long). The 3D camera also comprises a sensor group made up of a number of light-sensitive elements. The sensor group is connected to a processing chip (e.g. a CMOS sensor chip) that determines the time of flight of the emitted light. The processing chip simultaneously measures the distance to a number of target points in space in a few milliseconds. The 3D camera can also be based on a measuring principle in which the travel time of emitted light is recorded via the phase of the light. The phase position when sending the light and when receiving it is compared and the elapsed time or the distance to the reflecting user is determined from this. For this purpose, a modulated light signal is preferably emitted instead of short light pulses.

Further details on measurement principles are given in the following publications: " Fast Range Imaging by CMOS Sensor Array Through Multiple Double Short Time Integration (MDSI)", P. Mengel et al., Siemens AG, Corporate Technology Department, Munich, Germany and, and " A CMOS Photosensor Array for 3D Imaging Using Pulsed Laser", R. Jeremias et al., 2001 IEEE International Solid-State Circuits Conference, page 252 The use of a 3D camera to recognize gestures is Dissertation by Martin Haker, "Gesture-Based Interaction with Time-of-Flight Cameras", University of Lübeck, 2010 , known.

The components mentioned (in particular control device 8, light projection device 13, camera device 3, detection device 17, activation device 19, recognition device 14, sensor device 10, interface device 7, drive device 6) are, if present in an embodiment, arranged on the sliding door 4 and move with the sliding door 4. These components can be arranged on the sliding door 4, in particular in its interior, flexibly and as required; the camera of the Camera device 3 is to be arranged, for example, in such a way that it can record an image of the user 20, in particular of his face, through an opening in the outer door leaf 26. The opening has a diameter of a few millimeters, for example 3-5 mm. The same applies to the light projection device 13, the detection device 17 and the activation device 19, or to their components; they are to be arranged in a user-friendly manner, for example at a height that allows perception and/or operation.

In one embodiment, the control device 8 is arranged in an area between the door leaves 26, for example in the area of a rear side 31 of the sliding door 4 opposite the front side 30. In one embodiment, the rear side 31 of the sliding door 4 is not visible from the outside because the sliding door 4 can be wider than the passage area 24 and the rear side 31 therefore remains in the wall shell area 18 even when the sliding door 4 is in the closed position. The drive device 6 and the interface device 7 can also be arranged in this area. The electrical connections 32, 34 are accordingly arranged between the door leaves 26 and are not visible from the outside. However, the embodiments of the invention described here are not limited to this exemplary arrangement of the components.

Fig.6 shows a schematic representation of an embodiment of the control device 8 for the Fig.1 shown access control system 1. The control device 8 has an interface device 44 (I/O) which is electrically connected to a processor 40 (µP) and has several connections 43, 46, 48, 50, 52, 53, 55 for input and output signals. The connection 46 is connected to the drive device 6, the connection 48 to the sensor device 10, the connection 50 to the detection device 14 and the connection 52 via the interface device 7 to the building management system 12. In addition, the connection 43 is connected to the activation device 19, the connection 53 to the detection device 17 and the connection 55 to the light projection device 13.

The control device 8 also comprises a memory device 36 which is electrically connected to the processor 40. In the embodiment shown, the memory device 36 has a memory area 38 for a database (DB) and a Storage area 42 for one or more computer programs (SW) for operating the sliding door system 5. Depending on the configuration of the access control system 1, the operation of the sliding door system 5 includes one or more of the functionalities mentioned, for example opening the sliding door 4 as a function of the recognized user 20, displaying the status information 23, detecting a gesture (from outside or from inside) and the direction of movement (from inside). Depending on the design, the operation can also include determining a height H of the user 20. The computer program can be executed by the processor 40.

The database stores a data record for the user 20 who is authorized to access the restricted access zone 22. The stored data record is also referred to below as the user profile. The user profile includes user-specific data, e.g. name, information on proof of authorization (key number, PIN code, access code, including biometric data) and any time restrictions on access (e.g. access from Monday to Friday, from 7:00 a.m. to 8:00 p.m.). If several users 20 are authorized to access the restricted access zone 22, the database stores a user profile for each user 20. As an alternative to creating a user profile in the database of the storage device 36, the user profile can be created in a database of the building management system 12, whereby the access control system 1 can access this database via the communications network 28.

According to the embodiment described here, each user profile also specifies the maximum width W (see Fig. 2B ) the sliding door 4 is to be opened. It is also specified which gesture or gestures the user 20 can use to influence the operation of the sliding door 4. In one embodiment, the height H of the user 20 is also specified. The height H of the user 20 can be a maximum height or a height range, because the height can vary depending on the type of shoes and headgear for the user 20. In one embodiment, the length (in the y direction) of each user 20 can also be specified. The height H and the length (if present) are plausibility parameters for access control, as explained elsewhere in this description.

With the understanding of the principal system components described above and their functionalities, is described below in connection with Fig.7 a description of an exemplary method for operating the access control system 1 based on the Fig.1 shown situation. The system 1 is designed according to one embodiment such that the light projection device 13 has a standby mode and an operating mode. The person skilled in the art will recognize that in another embodiment no standby mode can be provided. The description of the method is made with reference to the user 20, who moves from the public zone 21 towards the sliding door 4 in order to enter the restricted access zone 22. The system 1 shown in Fig.4 The method shown begins in a step S1 and ends in a step S4. The person skilled in the art will recognize that the division into these steps is exemplary and that one or more of these steps can be divided into one or more sub-steps or that several of the steps can be combined into one step.

In a step S2, the light projection device 13 is activated by the control device 8. The activation switches the light projection device 13 from standby mode to operating mode. The activation takes place when the user 20 is detected approaching the sliding door 4, for example when the user 20 requests access to the restricted access zone 22 on the sliding door system 5. As explained above, the light projection device 13 is arranged in the interior of the sliding door 4 and is communicatively connected to the control device 8.

The person skilled in the art will recognize that the approach of the user 20 can be detected, for example, by means of a sensor that detects, for example, movement, noise or presence. The person skilled in the art is aware of suitable sensors for this purpose (e.g. infrared sensors, ultrasonic sensors, acoustic sensors, optical sensors and cameras). The approach or presence of the user 20 can also be detected by means of the above-mentioned camera 3 and/or detection device 14. Alternatively or additionally, the operating state can also be controlled as a function of time (time of day). If no standby mode is provided in the system 1, ie the light projection device 13 is constantly activated, step S2 can be omitted.

In a step S3, the light projection device 13 is controlled by the control device 8 in order to provide status information 23 specified by the control device 8 for the to project the status information 23 of the user 20 requesting access as a visible light projection onto a projection surface 27, 27a. The type of status information 23 and the projection surface 27, 27a can be designed according to one of the above-mentioned alternatives.

As explained above, the status information 23 can include a pictogram 23a and a text, e.g. the request to touch the pictogram 23a. If the user 20 with access authorization follows the request, the sliding door 4 is opened. The sliding door 4 can be opened according to a specified opening width W and/or depending on the recognition of one or more specified gestures. The user 20 can then pass through the passage area 24.

In one embodiment, the control device 8 controls the drive unit 6 in order to move the sliding door 4 back into the closed position after the user 20 has passed through. In one embodiment, the door closes after a specified period of time has elapsed after the sliding door 4 has reached the open position. It is assumed that the user 20 has passed through the passage area 24 during the specified period of time. In another embodiment, the door closes immediately after the user 20 has passed through the passage area 24. The passing through can be detected, for example, by means of the sensor device 10.

The person skilled in the art will recognize that the sliding door 4 can be opened according to a specified opening width W. The opening according to the specified opening width W can take place both when leaving the restricted access zone 22 and when entering the restricted access zone 22. The following explanations therefore relate to leaving and entering the restricted access zone 22.

The choice of the opening width W can be based on various motivations. According to one motivation, the opening width W is selected and stored in such a way that the user 20 can pass through the sliding door 4 or the passage area 24 comfortably and without feeling restricted or cramped. According to another motivation, the user 20's desire for increased safety determines the choice of the opening width W. The opening width W is therefore selected in such a way that the sliding door 4 initially only opens a crack, which is too narrow for the user 20.

Controlled by the processor device 40 and taking into account the opening width W stored in the user profile, the drive device moves the sliding door 4 until the width W is reached. This moves the sliding door 4 from the essentially closed position to a more or less open position. In the process, a part of the sliding door 4 slides into the wall shell area 18 of the door frame 2, as for example in Fig. 2B shown.

As stated above, a gesture of the user 20, who is located at the sliding door 4 in the detection field 11 of the sensor device 10, is recognized by means of the sensor device 10. The recognition of the gesture takes place according to a method that is described, for example, in the above-mentioned dissertation by Martin Haker.

As a function of the recognized gesture, the drive unit 6 can be controlled in deviation from the stored opening width W. In one embodiment, this means that the sliding door 4 is opened further than the opening width W appropriate for most everyday situations, so that the user 20 can also pass with larger objects (e.g. packages, suitcases) or a wheelchair.

In another embodiment, this means that the sliding door 4 is only opened wide enough for the user 20 to pass when the correct gesture has been recognized. If the gesture is not recognized as valid for the user 20, possibly even after repeated several times, the sliding door 4 is moved back to the closed position in one embodiment. In such a case, for example, a reset procedure can be initiated in which the user 20 must identify himself via another communication medium, for example to define a new gesture or to initiate remote opening. In addition, an alarm signal can be generated which is transmitted to a person responsible for the restricted access zone 22 (tenant, owner, building manager, etc.), for example as a text message via email or SMS.

An alarm signal can be generated by the control device 8 even if the the height H of the user 20 located in the passage area 24 determined by the sensor device 10 deviates from the height H or height range stored for this user 20 by a specified degree. The degree of deviation can be set in such a way that it expresses that the determined height H does not match the user 20 at all (is plausible). If an expected height H (based on the user profile) deviates significantly from the currently determined height, it can be concluded, for example, that it is not the user 20 to whom the authorization credential is assigned. It could be the case, for example, that an unauthorized person is in possession of the authorization credential (e.g. mobile phone, RFID tag) and is trying to gain access instead of the user 20.

A set of rules can be defined in the access control system 1 that specifies whether and which action should be initiated after an alarm signal. These actions can be situation-specific, i.e. it depends on the time (day or night) and the day (working day or weekend, holiday period) at which the alarm signal is generated. Examples of actions can be: an acoustic and/or visual alarm (siren, warning light), automatic notification of security personnel (police or private security service) and automatic notification of the person responsible for the access-restricted zone 22 (tenant, owner, building manager, etc.). The expert recognizes that these actions can also be combined.

In one embodiment, the control device 8 can be designed with an additional functionality that determines the length of time the user 20 spends in the passage area 24 and compares it with a specified length of time. This functionality is similar to a functionality for a security or elevator door, according to which a signal tone sounds if the door is kept open or blocked for too long. The specified length of time can also be stored in the data record of the user 20. If the specified length of time is exceeded, the alarm signal can also be generated in this case. This functionality can be used, for example, to reduce the risk of an unauthorized person attempting to block the open sliding door 4 or tamper with the sensor device 10.

In a further embodiment, the control device 8 can be provided with a further functionality. This functionality determines a length of the user 20 (in the y-direction) in the passage area 24 and compares this with a specified stored user length range. The sensor device 10, for example designed as a 3D camera with a TOF sensor, has the Fig. 1 and Fig. 2B shown detection field 11. In conjunction with the control device 8, the length of the user 20 can be determined. For example, a contour of the user 20 can be recognized from an image recording and his length can be determined from this. The specified user length range can also be stored in the data record of the user 20. If the specified user length range is exceeded, the alarm signal can also be generated in this case.

Referring again to the Fig. 2A-2C shown positions of the sliding door 4, a description of an embodiment of the sliding door system 5 follows below. Fig. 2A-2C each show a schematic representation of a top view of the sliding door system 5. In each of these top views, the components included in the sliding door 4, namely the sensor device 10 (S), the control device 8 (DC) and the drive device 6 (M), are shown; other components, such as the interface device 7 and its connection to the building management system 12, are not shown for reasons of illustration. The components, in particular the drive device 6 and the control device 8, are arranged inside the sliding door 4, in particular between the door leaves 26. The wall shell area 18 with the structure for receiving the sliding door 4 in the open position is shown in Fig. 2A-2C also shown.

The sensor device 10 is arranged on the front side 30. The arrangement is selected so that the electromagnetic radiation (light or radio waves) can spread unhindered in the direction of the passage area 24 during operation. The sensor device 10 can be arranged, for example, in the area of an upper guide rail or inserted into a recess on the front side 30 and protected from damage and dirt by a radiation-permeable cover. The electrical connection 32 ( Fig.1 ) between the sensor device 10 and the control device 8 and the electrical connection 34 ( Fig.1 ) run inside the sliding door 4, for example between the door leaves 26.

The illustrated embodiment of the sliding door 4 is based on a principle similar to that of EP2876241A1 known principle. It describes a sliding door system in which two opposing door surfaces are coupled to an actuator that moves the door surfaces towards or away from each other. In relation to the sliding door system 5 according to the embodiment described here, this means that the two door leaves 26 have a leaf distance d1 in the closed position of the sliding door 4. During the opening of the sliding door 4, the two door leaves 26 are moved by an actuator 9 ( Fig. 2A - 2C ) are moved towards each other to such an extent that they have a leaf distance d2 which is dimensioned such that the sliding door 4 in its fully or partially open position ( Fig. 2B and Fig. 2C ) has such a small thickness that it fits into the receiving structure of the wall shell area 18. The leaf distance d1 is greater than the leaf distance d2. When the sliding door 4 is pushed out of the wall shell area 18, the two door leaves 26 are moved away from each other (spread apart) so that the sliding door 4 in the closed state ( Fig. 2A ) has a defined thickness. The thickness is defined such that the outer sides of the two door leaves 26 in the closed position are essentially flush with the outer sides of the wall shell area 18 or its cladding. This results in an essentially smooth finish on both sides of the wall in the door area.

In one embodiment, the sliding door system 5 has a guide device on a door cross member, which supports the sliding door 4 and guides it on its path between the closed position and the open position. The sliding door 4 has a complementary device on its upper edge. The guide device and the complementary device work together when the drive device 6 causes the sliding door 4 to move and acts on the complementary device; they can, for example, form a system with a telescopic extension. The drive device 6 can, for example, comprise a motorized or pneumatic sliding drive that acts on the telescopic extension.

In one embodiment, the two door leaves 26 are moved towards or away from each other by the actuator 9. The actuator 9 can comprise a spreading device that is activated mechanically, electrically or electromechanically. The spreading device is designed to move the door leaves 26 towards each other when the sliding door 4 is to be opened and to move them away from each other when the sliding door 4 to be closed. The person skilled in the art will recognize that other spreading devices can be provided instead, for example pressure-operated cylinders.

Claims (14)

1. A system (1) for controlling an access to a restricted access zone (22) in a building, comprising,

   a sliding door system (5) which comprises a door frame (2) and a sliding door (4) which can be displaced in the door frame (2) between a closed position and an open position by means of a drive unit (6), wherein the door frame (2) has a passage region (24) and a wall shell region (18) which at least partially accommodates the sliding door (4) in the open position;

   a controller (8) which is arranged on the sliding door (4) and is communicatively connected to the drive unit (6), wherein the controller (8) is designed to move the sliding door (4) between the closed position and an open position; and

   a light projection device (13) which is arranged in an interior space of the sliding door (4) and is communicatively connected to the control device (8), wherein the light projection device (13) is designed to project status information (23) predetermined by the control device (8) onto a projection surface (27, 27a) as a visible light projection for a user (20) who requests access to the restricted access zone (22),

   wherein the sliding door (4) has an inner door leaf (26) facing the restricted access zone (22) and an outer door leaf (26) facing away from the restricted access zone (22), between which the interior space extends, wherein the outer door leaf (26) has an operating compartment (25) extending into the interior space, wherein the light projection device (13) is designed to radiate the light projection into the operating compartment (25).
2. The system (1) according to claim 1, wherein the projection surface (27) is arranged in the operating compartment (25) and extends between the inner door leaf (26) and the outer door leaf (26), so that the projected status information is visible to the user (20) requesting access.
3. The system (1) according to claim 1 or 2, wherein the light projection device (13) is arranged to project the status information onto the projection surface (27) arranged in the operating compartment (25) and/or a floor area (27a) in front of the sliding door (4).
4. The system (1) according to any of the preceding claims, comprising a detection device (17) arranged on the sliding door (4) and communicatively connected to the control device (8), wherein the detection device (17) is configured to detect a manual interruption of the projected status information (23).
5. The system (1) according to claim 4, wherein the detection device (17) comprises a light barrier.
6. The system (1) according to any of the preceding claims, comprising a detection device (3, 14) which is arranged on the sliding door system (5) or in its environment and is communicatively connected to the control device (8), wherein the detection device (3, 14) is designed to check an access authorization of the user (20) requesting access.
7. The system (1) according to claim 6, wherein the detection device (3) comprises a camera device (3), wherein the detection device (3) is configured to perform a method for face recognition.
8. The system (1) according to claim 6 or 7, wherein the detection device (14) comprises a radio device (16), wherein the detection device (14) is designed to detect and check a credential presented by the user (20), wherein the control device (8) is designed to cause the sliding door (4) to move in accordance with a stored opening width (W) if the credential is valid for the user (20).
9. The system (1) according to claim 7 or 8, in which the detection device (3, 14) is designed to generate a status signal when the user (20) requests access, and in which the control device (8) is designed to activate the light projection device (13) when the status signal is present.
10. The system (1) according to any of the preceding claims, wherein the sliding door (4) comprises an actuator (9) which is designed to position two mutually spaced, substantially parallel door leaves (26) of the sliding door (4) in a first position with a first leaf spacing (d1) when the sliding door (4) is in the closed position and in a second position with a second leaf spacing (d2) when the sliding door (4) is in the open position, wherein the first leaf spacing (d1) is greater than the second leaf spacing (d2).
11. A method of operating a system (1) for controlling access to a restricted access zone (22) in a building according to any of claims 1 to 10, wherein the system (1) comprises a sliding door system (5) and a control device (8) for the sliding door system (5), the method comprising:
    actuating a light projection device (13) by the control device (8), wherein the light projection device (13) is arranged in an interior space of a sliding door (4) of the sliding door system (5) and is communicatively connected to the control device (8), wherein the light projection device (13) is controlled by the control device (8) in order to project status information (23) predetermined by the control device (8) for a user (20) requesting access as a visible light projection onto a projection surface (27, 27a).
12. The method according to claim 11, wherein the status information (23) is projected by the light projection device (13) onto a projection surface (27) in an operating compartment (25) of the sliding door (4) and/or a floor area (27a) in front of the sliding door (4).
13. The method according to claim 11 or 12, comprising detecting a manual interruption of the projected status information (23).
14. The method according to any of claims 11 to 13, comprising detecting the user (20) by a detection device (3, 14) which is arranged on the sliding door system (5) or in the environment thereof and is communicatively connected to the control device (8), wherein the light projection device (13) is activated upon detection of the user (20).

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