Display device

Abstract

The invention relates to a display device (200, 300, 400, 600) comprising: at least one optical display (202, 302, 402, 602) with a display illumination (206, 306, 606) controllable by a display control (212, 612) with a control signal and a transparent protective screen (208, 308, 408, 608), a light sensor arrangement (238, 638) with at least one light sensor (226, 326, 626, 666) arranged on a narrow side (214, 216, 314, 316, 340, 342, 614, 616) of the transparent protective screen (208, 308, 408, 608), wherein the at least one light sensor (226, 326, 626, 666) is configured to detect the light intensity emanating from the narrow side (214, 216, 314, 316, 340, 342, 614, 616) and caused mainly by the display illumination (206, 306, 606), and an analysis module (236, 636), configured at least to detect damage to the transparent protective screen (208, 308, 408, 608),based on the detected light intensity and the control signal applied to the display illumination (206, 306, 606) during light intensity detection.

Description

[0001] The invention relates to a display device comprising at least one optical display with a display illumination controllable by a display controller with a control signal and a transparent protective screen. Furthermore, the invention relates to a method and a ticket vending machine.

[0002] Ticket vending machines, such as those used for train tickets, but also other applications, include optical displays. An optical display can be specifically designed to dynamically display different or variable data. For example, an optical display can be a touchscreen. A touchscreen is specifically designed to display changing data and detect user input.

[0003] An optical display is characterized in particular by a controllable display illumination. The display illumination, especially in the form of backlighting, particularly supports the display of the data content.

[0004] Display devices with an optical indicator or screen are frequently found in public areas (e.g., on streets, in train stations, in parking garages, etc.). A fundamental problem with current technology is that such display devices are repeatedly subjected to vandalism. It frequently happens that the optical display of a display device is damaged, for example, by a user exerting force (e.g., a blow) on the front of the display.

[0005] It is known in the prior art to protect an optical display by placing a transparent protective pane (e.g., a glass pane) in front of it. If the optical display, including the transparent protective pane, is struck, only the transparent protective pane (also called a sacrificial pane), which forms the front of the optical display, is damaged. While this generally prevents damage to the electronic components and / or similar parts of the optical display, a damaged protective pane at least impairs the display of the data content. In particular, the data content displayed by the damaged optical display may be unreadable or only partially recognizable to a user.With a touchscreen, the situation can be further complicated by the fact that user input may be impossible or only partially possible, meaning, for example, that purchasing and / or paying for tickets at a ticket machine is no longer possible. This leads to lost revenue and user dissatisfaction.

[0006] Therefore, there is a fundamental need in the prior art to detect a damaged transparent protective lens of an optical display device in a timely manner in order to repair it, in particular to replace it with an undamaged transparent protective lens. The prior art provides for this purpose in the following: Figure 1 The display device 100 shown with a sensor arrangement 198 is known, which is implemented by way of example in a ticket machine 120.

[0007] The display device 100 comprises an optical display 102 with a display layer assembly 104, a display illumination 106 in the form of a backlight, and a transparent protective screen 108 arranged over the front side 110 of the display layer assembly 104. At least the display illumination 106 can be controlled by a control signal via a display controller 112. Additionally, the display layer assembly 104 can be controlled by the display controller 112 with a display control signal.

[0008] Furthermore, the display device 100 comprises a sensor arrangement 198 according to the prior art. The sensor arrangement 198 is configured to detect damage to the transparent protective screen 108. The sensor arrangement 198 comprises a sensor light source 196, a sensor light receiver 194, and an evaluation module 192 connected to the sensor light receiver 194. In the prior art, the sensor light source 196 is located along the entire length of a first narrow side 114 of the transparent protective screen 108, and the sensor light receiver 194 is located along the entire length of a second narrow side 116 of the transparent protective screen 108. The second narrow side 116 is the narrow side 116 opposite the first narrow side 114.

[0009] As indicated by arrows 118, light is coupled into the first narrow side 114 of the transparent protective disc 108 by the sensor light source 196. The light 118 transmitted through the transparent protective disc 108 is received by the sensor light receiver 194 on the opposite narrow side and evaluated by the evaluation module 192. The evaluation module 192 is configured to evaluate the transmittance, or the light intensity "transmitted" through the transparent protective disc 108. If one or more cracks occur in the transparent protective disc 108, for example, due to an impact on the transparent protective disc, the transmitted light intensity decreases. A damaged transparent protective disc 108 can be detected by the evaluation module 192.

[0010] However, the state-of-the-art sensor arrangement has several disadvantages. It involves a complex setup with a sensor light source and an opposing sensor light receiver. Furthermore, the sensor light source and receiver must be positioned to monitor the entire transparent protective screen. As previously described, this typically requires the sensor light source to be positioned along the entire length of one narrow side. The same applies to the sensor light receiver. Additionally, the sensor light source requires electrical energy, thus increasing the overall energy consumption of the display device.

[0011] Finally, it was determined that the prior art sensor arrangement cannot reliably detect all types of damage. In particular, the front surface of the transparent protective screen 108 is frequently covered with paint, stickers, and / or the like. Such types of damage are not reliably detected by the prior art sensor arrangement because the light continues to be transmitted unchanged from the sensor light source to the sensor light receiver.

[0012] The invention is therefore based on the objective of creating a way to at least reduce the disadvantages of the prior art in a display device with an optical display, and in particular to detect different types of damage with improved reliability and reduced effort.

[0013] The problem is solved according to a first aspect of the invention by a display device according to claim 1. The display device comprises at least one optical display with a display illumination controllable by a display controller with a control signal and with a transparent protective screen. The display device comprises a light sensor arrangement with at least one light sensor arranged on a narrow side of the transparent protective screen. The at least one light sensor is configured to detect the light intensity emanating from the narrow side and caused essentially by the display illumination. The display device comprises an analysis module. The analysis module is configured at least to detect damage to the transparent protective screen, based on the detected light intensity and the control signal that is applied to the display illumination during the detection of the light intensity.

[0014] In contrast to the prior art, the invention provides a display device with a sensor arrangement that uses the (already) existing display illumination as a sensor light source. This reduces the disadvantages of the prior art and, in particular, enables the detection of different types of damage with improved reliability and reduced effort. The invention demonstrates that when the transparent protective screen is damaged, the light coupled in by the display illumination is reflected in such a way that it can be detected at one of the narrow edges. Specifically, it has been found that the reflection behavior changes when the transparent protective screen is damaged.In particular, the reflection behavior changes not only when a crack (or multiple cracks) is caused by an impact, but also when the front surface of the transparent protective visor is coated with paint, stickers, and / or the like. By taking the control signal into account, the analysis module can determine the altered reflection behavior in the transparent protective visor and, in particular, detect any damage that has occurred (immediately and with minimal effort).

[0015] According to the invention, a display device is provided. The display device can be a standalone device or integrated into another device, for example, a ticket machine or the like. In particular, the display device is designed for use in a public space.

[0016] The display device comprises an optical display. The optical display may, in particular, comprise a display layer arrangement, a display illumination, preferably a display control, and a (replaceable) transparent protective screen. The display illumination may be a backlight and / or a light-emitting layer of the optical display.

[0017] Depending on the type of optical display, the optional display layer arrangement can have one or more layers in a known manner (e.g., a translucent layer or various electrodes, color filters, liquid crystal layer, polarizers, etc.).

[0018] The transparent protective disc (also referred to as a protective plate) forms, in particular, the outer front panel of the optical display, followed by the display layer assembly. Preferably, the transparent protective disc (also referred to as a sacrificial disc) is designed to protect the display layer assembly from damage. The transparent protective disc is, in particular, designed to be replaceable. Preferably, the transparent protective disc can be made of glass or a transparent plastic. In this context, "optically transparent" means, in particular, that the majority of visible electromagnetic radiation is transmitted through such a protective disc. An optically transparent protective disc is understood to be, in particular, a disc or plate with a light transmittance of at least greater than 70%, preferably greater than 75%, and particularly preferably greater than 80%.

[0019] The display layer arrangement is followed in particular by the display illumination, for example in the form of a backlight. A light-emitting layer can also be integrated into a display layer arrangement. The display illumination is configured to illuminate the display layer arrangement and / or the transparent protective screen (in a known manner) in order to display the data content of the optical display, based on a control signal from the display controller. In particular, the display illumination can be controlled by the control signal from the display controller (for example, a microprocessor) (in a known manner). According to one embodiment of the display device according to the invention, the display layer arrangement can be controlled by the display controller with a display control signal (in a known manner). In variants of the invention, this can be omitted, for example, if no variable data content is displayed.

[0020] In particular, it has been found that the light coupled into the transparent protective screen depends on the control signal applied to the display backlight. In other words, the light coupled, for example, first into the display layer assembly and then into the transparent protective screen is controlled by the display controller via the control signal.

[0021] The display illumination is specifically designed to couple light into the transparent protective screen in a direction substantially orthogonal to the base or back (or front) of the transparent protective screen. In particular, the light is coupled (only) into the back of the transparent screen (and not via any narrow side).

[0022] For example, the optical display can be an LCD (liquid-crystal display), in particular a touch display. An LCD can (in a known manner) comprise a backlight and a display layer arrangement. The optical display can also be an OLED (organic light-emitting diode) display or a micro LED (light-emitting diode) display. An OLED display can (in a known manner) comprise a display layer arrangement with a light-emitting layer. A micro LED display can (in a known manner) comprise a display layer arrangement with a light-emitting layer (containing microLEDs).

[0023] According to the invention, the sensor arrangement comprises at least one light sensor. The at least one light sensor is configured to detect light, in particular the light intensity or level (or amplitude) of the light. In particular, the at least one light sensor can be a CCD (charge-coupled device) sensor, a photodiode, a phototransistor, and / or the like. Preferably, the at least one light sensor can be a linear light sensor.

[0024] In particular, the at least one light sensor generates an (electrical) light intensity signal, the amplitude of which depends in particular on the light intensity detected by the light sensor. In particular, the amplitude can depend essentially proportionally on the light intensity detected by the light sensor.

[0025] It is understood that in variants of the invention, the display device, in particular the analysis module, may have at least one filter to filter out, in particular, interfering components (e.g., noise) from the light intensity signal provided by the light sensor. For example, at least one low-pass filter may be provided.

[0026] The transparent protective disc or plate can comprise a front (also referred to as the front surface) and a back (also referred to as the rear surface) opposite the outer front. For example, the transparent protective disc can have a thickness between 0.1 cm and 2 cm. The front and back surfaces form the base. In particular, the front and back surfaces are identical, i.e., they have the same outline and area. At least one narrow side can be arranged between the front and back surfaces. In a preferred embodiment, the base surface can be rectangular. In this case, the transparent protective disc can have four narrow sides. For example, a circular base surface can have one circumferential narrow side, and a triangular base surface can have three narrow sides.

[0027] The at least one light sensor is located on at least one narrow side (and therefore not on the front or back) of the transparent protective screen. Specifically, each light sensor in the sensor arrangement is located on a narrow side. In other words, a light sensor cannot be located on either the front or back.

[0028] According to the invention, the at least one light sensor detects the light intensity emitted at the (corresponding narrow side of the transparent protective screen). The light intensity detectable at the narrow side is essentially caused by the display illumination. "Essentially caused by the display illumination" in this context means, in particular, that in practice it is almost unavoidable that ambient light also contributes, to a small extent (e.g., 0 to 5%), to the light intensity detectable at the narrow side by a light sensor. However, the display device itself does not, in particular, have any other light source that could be the cause of the detectable light intensity.

[0029] Furthermore, the display device includes an analysis module, for example, formed by hardware and / or software. The analysis module is specifically configured to evaluate the detected light intensity and the control signal. In particular, the at least one light sensor can be configured to (continuously measure and continuously provide) the light intensity signal generated by the light sensor, depending on the light intensity detected by that light sensor.

[0030] Furthermore, the display control can be configured at least to (continuously) provide the control signal that controls the display backlight. Preferably, the evaluation module can perform a time-synchronized evaluation of the at least one light intensity signal and the control signal.

[0031] In particular, it has been recognized that damage to the transparent protective screen cannot be reliably detected solely based on the measured light intensity, since the detectable light intensity always depends on the light coupled into the transparent protective screen. According to the invention, by configuring the analysis module specifically to evaluate the light intensity detected by the at least one light sensor and the control signal, and especially to evaluate the at least one light intensity signal and the control signal in a time-synchronized manner, any damage to the transparent protective screen can be detected (almost immediately). This is particularly possible even with damage in the form of stickers and / or paint, which only result in a slight change in reflection behavior.

[0032] According to a preferred embodiment of the display device according to the invention, the light sensor arrangement can exclusively comprise or use the display illumination as the light sensor source. In other words, the light sensor arrangement need not have a separate light sensor source (as in the prior art). In particular, no light sensor source is arranged on a narrow side of the transparent protective screen. Preferably, the light sensor arrangement uses exclusively the display illumination as the light sensor source. The assembly effort and the energy consumption of the display device according to the invention can be reduced.

[0033] According to a further embodiment of the display device according to the invention, the control signal can be a pulse width modulation signal (PWM signal). In particular, at least the brightness or light intensity with which the optical display is operated can be controlled by means of a PWM signal.

[0034] According to a further preferred embodiment of the display device according to the invention, the analysis module can be configured to detect damage to the transparent protective screen by detecting a minimum change in the detected light intensity (in particular, the detected amplitude of the at least one provided light intensity signal) while a control signal (or an unchanged amplitude of the control signal) is simultaneously present. In particular, the temporal profile of the provided light intensity signal can be evaluated together with the temporal profile of the control signal.If a change in the detected light intensity is greater than the (predefinable) minimum change (for example, a predefined amplitude change), especially without a change in the control signal—that is, without a change in the light intensity coupled into the transparent protective screen by the display illumination—damage to the transparent protective screen can be detected. In particular, a damaged protective screen is detected with increased reliability.

[0035] According to a further embodiment of the display device according to the invention, the analysis module can be configured to determine, in particular as a minimum change, a dynamic minimum change (for example, an amplitude change) based on the control signal applied to the display illumination during the detection of the light intensity. The analysis module can be configured to detect damage to the transparent protective screen based on the dynamic minimum change and the detected light intensity (or the maximum amplitude of the light intensity signal). In particular, it has been recognized that the required minimum change can depend on the applied control signal. By taking the control signal into account, the detection of damage to the transparent protective screen can be further improved.

[0036] According to a preferred embodiment of the display device according to the invention, the analysis module can be configured to determine a (level or amplitude) difference between a maximum or maximum amplitude of the control signal and a maximum or maximum amplitude of the detected light intensity or the provided light intensity signal. The analysis module can be configured to determine the degree of damage to the detected damage of the transparent protective screen based on this determined difference. For example, two or more different degrees of damage (e.g., slight, moderate, severe, or partially damaged, completely damaged, etc.) can be predefined.Depending on the specific difference, especially the magnitude of the specific difference, the corresponding degree of damage can be determined (for example, using an assignment table in which (dynamically determined) height ranges are each assigned to a degree of damage).

[0037] Preferably, the analysis module can be configured to determine a (level or amplitude) difference between the (dynamically determined) minimum change and the maximum of the detected light intensity (or light intensity signal). Depending on the detected degree of damage, it is particularly possible to assess whether immediate repair (i.e., in particular, replacement of the damaged protective lens) should be carried out or whether it can be postponed, as a significant degree of functionality is still present. Especially when dealing with a large number of damage reports, each containing at least the degree of damage, the available repair resources can be used efficiently.

[0038] According to a further embodiment of the display device according to the invention, the light sensor arrangement can comprise at least two light sensors. The at least two light sensors can be spaced apart from each other (for example, between 0.5 cm and 30 cm). Preferably, the two light sensors can be arranged on two different narrow sides of the transparent protective screen. By providing at least two spaced-apart light sensors, the detection sensitivity of the sensor arrangement can be improved. Preferably, a first light sensor can be arranged on a first narrow side and a second light sensor on another narrow side opposite the first narrow side. Even minor damage can be detected.

[0039] According to a further preferred embodiment of the display device according to the invention, the transparent protective screen can have a substantially rectangular base shape or surface, as already described in detail. At least one light sensor can be arranged on at least three of the four narrow sides of the transparent protective screen, preferably on all four narrow sides. By arranging at least one light sensor on each narrow side of the transparent protective screen, the detection sensitivity can be further improved. In particular, one or more light sensors can be arranged on each narrow side of the transparent protective screen, since, as described, in contrast to the prior art, a light sensor source on one narrow side can be dispensed with.

[0040] According to a particularly preferred embodiment of the display device according to the invention, the at least two light sensors can each be configured to provide a respective light intensity signal, as already described in detail. The analysis module can be configured to determine a principal damage position based at least on the respective light intensity of the two light intensity signals (and in particular the respective sensor position). In other words, at least two of the light sensors of the sensor arrangement, preferably all light sensors of the sensor arrangement, can be used to determine a principal damage position.

[0041] As previously described, preferably three or more light sensors can be provided, distributed along the narrow side(s). In particular, at least one light sensor can be provided on each narrow side.

[0042] The evaluation module can know the respective positions of the individual light sensors in the sensor array. In particular, a light intensity signal provided or received by the evaluation module can be assigned to a specific light sensor (or its position) by the analysis module.

[0043] At least two of the received light intensity signals can be evaluated by the analysis module. In particular, the respective light intensity signals provided by the two or more light sensors can be evaluated by the evaluation module, preferably comparing their respective (level or amplitude) maxima. It has been found, in particular, that the light sensor exhibiting the light intensity signal with the highest amplitude is the light sensor located closest to the main damage location, while the light sensor exhibiting the light intensity signal with the lowest amplitude is the light sensor located furthest from the main damage location.Preferably, a triangulation technique or the like can be applied by the evaluation module, based on the respective maxima of the provided light intensity signals, to determine the main damage location. In particular, with at least four, preferably more, light sensors distributed along the narrow sides, the main damage location can be reliably determined by appropriately evaluating the provided light intensity signals. Specifically, the analysis module can be configured to determine the respective distance of each light sensor to the main damage location, based on the respective position of each light sensor and the respective maximum amplitude of the respective light intensity signal.

[0044] In this context, a primary damage location or primary damage location refers specifically to the area of ​​the transparent protective screen that is substantially damaged, for example, exhibiting cracks and / or a tear, or bearing a sticker or paint. A primary damage location can be specified, for instance, in the form of coordinates from a predefined coordinate system applied to the transparent protective screen. As will be described later, a primary damage location can also be defined or determined, for example, by specifying the grid sub-areas that exhibit damage.

[0045] According to a further preferred embodiment of the display device according to the invention, the display device can include the display control unit, as already described. The display control unit can be configured to change the data content displayed by the optical display by controlling the display illumination and / or the display layer arrangement, based on the specified primary damage position (and, in particular, the additionally specified degree of damage). In particular, the analysis module of the display control unit can provide a specific primary damage position and, in particular, a specific degree of damage. Changing the data content displayed by the optical display can be achieved by controlling the display with a modified control signal and / or a modified display control signal.

[0046] For example, changing the data content displayed by the optical display via the display control can include shrinking the window in which all the data content is displayed, particularly depending on the main damage location (and possibly a predefined minimum window size). Furthermore, the reduced window can be displayed in an (undamaged or minimally damaged) area of ​​the optical display, depending on the main damage location. In other words, the reduced window can be displayed in an area of ​​the optical display that has no or only minor damage.

[0047] Alternatively or additionally, the data content can comprise multiple (separate) data elements. Each data element can be assigned a display priority. For example, a data element that should always be displayed (such as important information for a user, a user-operated keypad, a data element essential to the function of the display device or the device in which the display device is implemented, etc.) can be assigned a high, particularly the highest, priority, while a data element that does not always need to be displayed (such as an advertisement, an area without a user-operated keypad, a data element inessential to the function of the display device or the device in which the display device is implemented, etc.) can be assigned a low, particularly the lowest, priority.

[0048] Changing the data content displayed by the optical display via the display control can involve showing data elements in the (undamaged or minimally damaged) area of ​​the optical display that exhibits no or only minor damage, depending on the assigned priority. Initially, only the one or more data elements with the highest priority in the minimally damaged area of ​​the optical display are shown. If another sub-area is available in the minimally damaged area of ​​the optical display, the one or more additional data elements with the second-highest priority can be shown (and so on). Data elements that can no longer be displayed in the minimally damaged area of ​​the optical display (due to space limitations and especially priority) can be omitted entirely or displayed in the main damaged area.

[0049] In particular, controlling the display lighting with a modified control signal and / or display control signal includes controlling it in such a way that at least one user-operated control panel of a touch display is shown outside the main damage position.

[0050] Even with a damaged transparent protective screen, continued operation of the display device and / or the device in which the display device is implemented can be ensured to the best possible extent, particularly until the display device is repaired. Then the optical display can be controlled again in such a way that the original data content is (completely) displayed across the entire display area of ​​the optical display.

[0051] According to a further preferred embodiment of the display device according to the invention, the display device can include the display control, as already described. The display control can be configured to control the display illumination with a predefined test control signal (as a control signal for the display illumination) for a predefined test duration.

[0052] The analysis module can be configured to detect damage to the transparent protective screen, based on the light intensity recorded during the test and the test control signal. In particular, it has been found that the detection sensitivity can be further improved by using a special test control signal that couples in light with a predefined brightness and / or intensity, which is particularly well-suited for detecting damage to a transparent protective screen. For example, the test control signal can be configured to couple in light with maximum brightness and / or intensity.

[0053] According to a further embodiment of the display device according to the invention, the predefined test control signal can be based on a predefined time-dependent test sequence pattern, with which, in particular, the entire screen area of ​​the optical display is controlled, preferably in a grid pattern. Specifically, a grid (for example, with rectangles or similar grid sub-areas) can be superimposed over the entire screen area of ​​the optical display. Each of these grid sub-areas can then be controlled, for example, sequentially, in particular with a predefined light intensity and / or brightness and / or color (while the other grid sub-areas remain unilluminated). With such a test scenario, the entire screen area of ​​the optical display can be scanned for damage to the transparent protective screen.In particular, for each grid sub-area, a previously described evaluation of at least one light intensity signal, and especially of a plurality of light intensity signals, can be performed. For example, the respective maximum amplitudes of the respective light intensity signals for all grid sub-areas can be compared again. For example, it can be determined in which grid sub-area the at least one amplitude of the plurality of light intensity signals of all grid sub-areas is highest. These grid sub-areas can, in particular, be determined as the main damage location area. In particular, the main damage location area can be determined in an even more reliable manner.

[0054] Controlling the display backlight with a predefined test control signal can preferably include displaying a predefined time-dependent test pattern via the optical display for a predefined test duration, as described above. Additionally, control with a predefined test display control signal is possible.

[0055] The test sequence pattern or test control signal can be stored in a data memory of the display device. The display control can be configured to execute the test procedure at predefined times (e.g., regularly when no user action is detected (e.g., for a predefined period of time), and / or similar).

[0056] For example, the test control signal can be a DC voltage signal and / or be configured to display different (predefined) colors.

[0057] According to a further embodiment of the display device according to the invention, a reflective layer can be arranged on at least part of the narrow side areas of the transparent protective screen (where, in particular, no light sensor is arranged). Light can be reflected by the reflective layer on the narrow sides where no light sensor is arranged and, in particular, then detected by the at least one light sensor. The measurement sensitivity can be further improved. Even minor damage to the transparent protective screen can be detected.

[0058] According to a further embodiment of the display device according to the invention, the display device can include a mounting frame. The mounting frame is specifically designed for (mechanically) holding the transparent protective screen. For example, the transparent protective screen can be inserted (precisely) into the mounting frame. The mounting frame can include fastening means for attaching the mounting frame to a housing (or the like) of the display device and / or the device in which the display device is implemented.

[0059] The mounting frame preferably includes at least one light sensor. In particular, the light sensor can be integrated into the mounting frame such that, when the transparent protective cover is installed (i.e., when it is properly inserted in the mounting frame), the light sensor is positioned on a narrow edge of the transparent protective cover (especially such that light emanating from the narrow edge is detected by the light sensor). For example, the light sensor can make direct contact with the narrow edge when the cover is installed. The mounting frame can include electrical contact means for a communication link with the analysis module. A damaged transparent protective cover can be easily replaced. Furthermore, the at least one light sensor can be reused with each new transparent protective cover. The transparent protective cover itself does not need to be equipped with a light sensor.

[0060] Furthermore, the reflective layer can preferably be attached to the mounting frame in such a way that a reflective layer is present on at least part of the narrow side areas (where, in particular, no light sensor is located) of the transparent protective cover. A damaged transparent protective cover can be easily replaced. Moreover, the at least one reflective layer can be reused with each new transparent protective cover. The transparent protective cover itself does not need to be provided with a reflective layer. A reflective layer further improves the detection sensitivity.

[0061] According to a further embodiment of the display device according to the invention, the at least one light sensor can be (completely) surrounded by the narrow side of the transparent protective screen and an opaque encapsulation. The encapsulation can, in particular, be formed by the (previously described) mounting frame. By providing an encapsulation, it can be ensured that ambient light has only a minimal impact (e.g., 0 to 1%) on the detectable light intensity at the narrow side by the at least one light sensor. The reliability in detecting damage can be further improved.

[0062] According to a further embodiment of the display device according to the invention, the display device can comprise at least one communication module. The communication module can be configured to send a damage message (via a (wireless and / or wired) communication network to a central unit) upon detection of damage to the transparent protective screen. In particular, the damage message can be generated and sent immediately upon detection of damage to the transparent protective screen. The damage message can contain an identifier of the display device and / or the device in which the display device is implemented, and / or a position indicator of the display device and / or the device in which the display device is implemented. The location can be determined from the identifier, for example, by means of a location database.Furthermore, the damage report can preferably include at least the degree of damage. Based on a damage report, the central office can arrange for the repair of the damaged transparent protective screen, in particular by replacing the damaged transparent protective screen.

[0063] Another aspect of the invention is a method for detecting damage to an optical display of a display device, in particular a previously described display device (according to claim 1). The method comprises: Detect, by means of at least one light sensor arranged on a narrow side of a transparent protective screen of the optical display, an emitted light intensity, which is substantially caused by the display illumination, and detect, by means of an analysis module (of the display device), damage to the transparent protective screen, based on the detected light intensity and a (provided) control signal that is applied to a display illumination of the optical display during the detection of the light intensity.

[0064] In particular, the method may include receiving the control signal, which is present at a display illumination of the optical display during the detection of the light intensity, from the display control.

[0065] Preferably, upon detection of damage to the transparent protective screen, a communication module of the display device can be used to send a damage message, as previously described.

[0066] A further aspect of the invention is a ticket vending machine. The ticket vending machine comprises at least one ticket processing module. The ticket vending machine comprises at least one display device as previously described (according to claim 1). The at least one ticket processing module can be a ticket generation module, a ticket settlement module, a ticket issuance module, a ticket validation module, and / or the like.

[0067] In further variants of the invention, the display device can be implemented in or form other devices, such as information displays and / or the like.

[0068] A previously described module (e.g., analysis module), device, or apparatus can comprise at least some hardware elements (e.g., processor, memory, etc.) and / or at least some software elements (e.g., executable code). It should be noted that terms such as "first," "second," "further," etc., do not indicate a sequence but serve primarily to distinguish between two elements (e.g., light sensor, etc.).

[0069] The features of the display devices, the ticket machines, and the methods are freely combinable. In particular, features of the description and / or the dependent claims, even by completely or partially circumventing features of the independent claims, can be independently inventive, either on their own or freely combined.

[0070] There are now numerous possibilities for designing and further developing the display devices, ticket vending machines, and method according to the invention. Reference is made, on the one hand, to the claims subordinate to the independent claims, and on the other hand, to the description of exemplary embodiments in conjunction with the drawing. The drawing shows: Fig. 1 a schematic view of a ticket vending machine with a display device according to the prior art, Fig. 2 a schematic view of an embodiment of a display device according to the present invention, Fig. 3a a schematic top view of a further embodiment of a display device according to the present invention, Fig. 3b a schematic sectional view of the display device according to Figure 3aFig. 4a a schematic top view of a further embodiment of a display device according to the present invention in a damage-free state, Fig. 4b a schematic top view of the display device according to Figure 4a in a damaged state, Fig. 4c shows a further schematic top view of the display device according to Figure 4a in a damaged state, Fig. 4 shows a further schematic top view of the display device. Figure 4ain a damaged state with a grid, Fig. 5 a diagram of an embodiment of a method according to the invention, Fig. 6 a schematic view of an embodiment of a ticket vending machine according to the invention with an embodiment of a display device according to the present invention, Fig. 7a exemplary signal waveforms of an intensity signal and a control signal in a damage-free state of the display device according to the present invention, Fig. 7b exemplary signal waveforms of an intensity signal and a control signal in a damaged state of the display device according to the present invention, and Fig. 7c further exemplary signal waveforms of an intensity signal and a control signal in a damaged state of the display device according to the present invention.

[0071] In the following, similar reference symbols are used for similar elements.

[0072] The Figure 2 Figure 1 shows a schematic view of an embodiment of a display device 200 according to the present invention. The display device 200 can be a stand-alone device or integrated into another device (not shown), for example, a ticket machine. In particular, the display device 200 is designed for use in a public space.

[0073] The display device 200 comprises at least one optical display 202. The optical display 202 comprises at least one display illumination 206 and at least one transparent protective screen 208. Preferably, the optical display 202 comprises at least one display controller 212, for example formed by a microprocessor and / or the like. The transparent protective screen 208 can be made of glass and / or a plastic material.

[0074] The transparent protective screen 208 is in particular formed in a plate-like shape with a front side 228, a back side 230 and at least one narrow side 214, 216. The front side 228 is in particular directed outwards (in the direction of a user not shown). The back side 230 faces the display illumination 206.

[0075] The display backlight 206 can be controlled, in particular, by means of the display controller 212. The display controller 212 is at least configured to control the display backlight 206 with a control signal.

[0076] Furthermore, a light sensor arrangement 238 of the display device 200 comprises at least one light sensor 226 arranged on a narrow side 216 of the transparent protective screen 208. The light sensor 226 is, for example, a CCD sensor, a photodiode, or the like. The at least one light sensor 226 is configured to detect the light intensity emanating from the narrow side 216 and caused essentially by the display illumination 206.

[0077] Again Figure 2 Furthermore, it can be seen that the display illumination 206 is specifically designed to couple light 218 into the transparent protective screen 208 in a substantially orthogonal direction to the base surface or rear side 230 (or front side 228) of the transparent protective screen 208 (indicated by the right angles between an arrow representing the light and the rear side 230).

[0078] The light sensor arrangement 238 includes, in particular, only the display illumination 206 as a light sensor source (and thus no separate light source).

[0079] In particular, the invention exploits the fact that the reflection behavior changes when the transparent protective disc 208 is damaged. For example, in the Figure 2Damage 234 is represented as a crack. Damage 234 causes the light 218 striking this damage to be partially deflected (scattered) and partially reflected (see arrow 232). As can be seen, this reflected light 232 emerges, for example, at the narrow side 216 and can be detected by the light sensor 226. Without such damage, only a low light intensity can be detected at the narrow side due to the described orthogonal coupling of the light with respect to the base or back side 230 (or front side 228) of the transparent protective disc 208.

[0080] In particular, the light sensor 226 can provide the analysis module 236 with the detected light intensity in the form of an (electrical) light intensity signal. Furthermore, the display controller 212 can provide the control signal to the analysis module 236.

[0081] The analysis module 236 is configured at least to detect damage 234 to the transparent protective screen 208, based on the detected light intensity (in particular the amplitude profile of the (electrical) light intensity signal) and the control signal (in particular the amplitude profile of the (electrical) control signal) that is applied to the display illumination 206 during the detection of the light intensity.

[0082] This detection process includes, in particular, a (synchronized) evaluation of a light intensity signal from the light sensor 226 and the control signal. Specifically, the amplitude of the light intensity signal and the amplitude of the control signal can be evaluated by the analysis module 236 to detect damage 234. Preferably, the analysis module 236 can be configured to detect damage to the transparent protective screen 208 by detecting a minimum change in the detected light intensity (detected amplitude), especially when the control signal remains unchanged. For example, the analysis module 236 can be configured to determine, as a minimum change, a dynamic minimum change based on the control signal applied to the display illumination 206 during the detection of the light intensity.The analysis module 236 can be configured to detect damage to the transparent protective screen based on the minimum dynamic change and the detected light intensity.

[0083] The optical display 202 can be, for example, an LCD screen, an OLED screen, or a Micro LED screen.

[0084] The Figures 3a and 3b Figure 1 shows a top view and a sectional view of a further embodiment of a display device 300 according to the present invention. To avoid repetition, only the differences from the embodiment according to Figure 2 are essentially described below. Figure 2 explained and otherwise, for example, referred to the explanations regarding Figure 2 Reference was made to this. Furthermore, details such as the display controls and the analysis module have been omitted here solely for the sake of clarity.

[0085] The display device 300 comprises an optical display 302. In the present embodiment, the optical display 302 comprises a transparent protective screen 308, a display layer arrangement 304 (with one or more layers, as described), a display illumination 306 and a (not shown) display control.

[0086] The illustrated transparent protective screen 308 comprises a front side 328 and a back side 330, as well as four narrow sides 314, 316, 340, 342. In particular, the transparent protective screen 308 has a rectangular base shape. The base shape of the display layer arrangement 304 and the shape of the display illumination 306 can correspond to the base shape of the transparent protective screen 308.

[0087] Preferably, at least one light sensor 326 (for clarity only a single light sensor 326 is shown) can be included on at least two narrow sides 314, 316, 340, 342, preferably on at least three narrow sides 314, 316, 340, 342.

[0088] The display device 300 comprises, in particular, a mounting frame 344. Specifically, at least the transparent protective lens 308 can be inserted (precisely fitting) and, in particular, interchangeably into the mounting frame 344. The mounting frame 344 can have (not shown) fastening means for interchangeably attaching the mounting frame 344, for example, to a housing of a device in which the display device 300 is installed. The other elements of the optical display 302 can be installed in the housing of the device.

[0089] As can be seen, the at least one light sensor 326 can be arranged, and in particular mounted, in the mounting frame 344. A (wired) connection to the analysis module can be established via electrical contact means (not shown), which may be integrated into the mounting frame, when the mounting frame 344 is installed. The at least one light sensor 326 is arranged in the mounting frame 344 such that, when the transparent protective screen 308 is in place, the light sensor 326 makes direct contact with a narrow side 314, 316, 340, 342.

[0090] Optionally, a reflective layer 346 can be arranged on at least a portion of the narrow side areas (where, in particular, no light sensor 326 is arranged) of the transparent protective screen 308. Light can be reflected by the reflective layer 346 on the narrow sides 314, 316, 340, 342, or their portions where no light sensor 326 is arranged, and in particular then be detected by the at least one light sensor 326. The reflective layer 346 can be attached to the mounting frame 344 such that a reflective layer 346 is arranged on at least that portion of the narrow side areas (where, in particular, no light sensor 326 is arranged) of the transparent protective screen 308.

[0091] In particular, the mounting frame 344 can be made of an opaque material. This allows the mounting frame 344 to be used as an encapsulation for the at least one light sensor 326. Preferably, the at least one light sensor 326 can be surrounded by the narrow side 314, 316, 340, 342 of the transparent protective screen 308 and an opaque encapsulation (in this case formed by the mounting frame 344).

[0092] The Figures 4a, 4b and 4c The figures show various top views of a further embodiment of a display device 400 according to the present invention. To avoid repetition, only the differences to the embodiments according to are essentially described below. Figure 2 and Figures 3a, 3b explained and otherwise, for example, referred to the explanations regarding Figure 2 and / or the Figures 3a, 3bReference was made. Furthermore, details such as the display control, display lighting, and analysis module have been omitted here solely for the sake of clarity.

[0093] In particular, the display device 400 is used in the Figure 4a shown with a transparent protective disc 408 in an undamaged condition, while the Figure 4b and 4c The display device 400 shows a transparent protective screen 408 in a damaged condition.

[0094] Again Figure 4a As can be seen, the optical display 402 shows data content 450 with three exemplary data elements 452, 454, 456. It is understood that in variants of the invention, data content with more or fewer data elements may be provided. In particular, the data content or the data elements may be variable, for example, depending on user input.

[0095] In its undamaged state, the data elements 452, 454, and 456 are distributed across the entire screen surface 458. A data element 452, 454, or 456 can be information (e.g., fare information, journey information, information about function, fault information, parking fare information, advertising, etc.) and / or a function field (e.g., on a touch display) with which a user can, for example, select or choose a data element, i.e., make a user input (in a generally known manner).

[0096] In the Figure 4b and 4c Damage has occurred to the transparent protective screen 408, for example, due to an impact on the transparent protective screen 408. For example, the impact may have led to cracks, as shown in the Figure 4b and 4c as indicated.

[0097] Preferably, the analysis module can be configured to determine a main damage position 460 or a main damage area of ​​the damage, based at least on the respective light intensity of two or more light intensity signals from two or more light sensors (not shown) distributed along the narrow sides. In particular, by evaluating the respective maximum amplitudes of the two or more light intensity signals and the respective known light sensor positions, it can be determined in which area of ​​the screen surface 458 or the front side of the transparent protective screen 408 the damage is located at least predominantly or substantially, i.e., the main damage position 460. In other words, the analysis module can be configured to determine the substantially undamaged area 462 of the screen surface 458 or the front side of the transparent protective screen 408, as already described.

[0098] In preferred embodiments of the invention, the display control can be configured to control the display illumination with a predefined test control signal in order to determine the main damage position 460 and / or the damage-free area 462 of the screen surface 458 with particular precision. The test control signal can be based on a predefined time-dependent test sequence pattern, with which, in particular, the entire screen area of ​​the optical display can be controlled, preferably in a grid pattern. In particular, a grid 464 with predefined grid sub-areas 461, 463 (for example, in the form of rectangles, especially squares) can be superimposed over the entire screen surface 458 of the optical display 402, as shown in Figure 4dThis is shown schematically. Each of these grid sub-areas 461, 463 can then be controlled, for example sequentially (indicated by the arrows), particularly with a predefined light intensity and / or brightness and / or color. For example, each grid sub-area 461, 463 can be illuminated individually in succession, while all other grid sub-areas 461, 463 remain unilluminated during this control period. In this example, only grid sub-area 463 is illuminated, while all other grid sub-areas 461 remain unilluminated. It is understood that any control sequence is possible.

[0099] In particular, for each grid sub-area, a previously described evaluation of the majority of light intensity signals can be performed. For example, the respective maximum amplitudes of the respective light intensity signals for all grid sub-areas can be compared again. For example, it can be determined in which grid sub-areas 461, 463 the at least one amplitude of the multitude of light intensity signals of all grid sub-areas 461, 463 is high, in particular exceeding a predefined minimum change. This at least one grid sub-area 461, 463 can in particular be determined as the main damage location or main damage location area.

[0100] The display control can preferably be configured to change the data content 450 displayed by the optical display 402 by controlling the display illumination and / or the display layer arrangement, based on the specified main damage position 460 (and in particular the additionally specified degree of damage) or the specified damage-free area 462. In particular, the analysis module of the display control can provide a specific main damage position 460 and, in particular, the specified degree of damage (or the specified damage-free area 462). Changing the data content 450 displayed by the optical display 402 can be effected by the display control using a modified control signal and / or a modified display control signal.

[0101] For example, as in Figure 4bAs shown, changing the data content 450 displayed by the optical display 402 by means of the display control includes shrinking the window 465 in which the entire data content 450 is displayed (especially compared with Fig. 4a ), depending on the specific main damage position 460 (and in particular the additionally specified degree of damage) or the specific damage-free area 462 (and possibly a predefined minimum window size). Furthermore, the reduced window 465 can be positioned or displayed in the damage-free area 462, i.e., an area 462 that has no or only minor damage.

[0102] Alternatively or additionally, as in Figure 4cAs shown, it is intended that the data content 450 can comprise a plurality of data elements 452, 454, 456. Each data element 452, 454, 456 can be assigned a display priority. For example, a data element (e.g., 452) that should always be displayed (e.g., important information for a user, a user-operable keypad, a data element essential to the function of the display device 400 or the device in which the display device 400 is implemented, etc.) can be assigned a high, in particular the highest, priority, while a data element (e.g., 456) that does not always need to be displayed (e.g., an advertisement, an area without a user-operable keypad, a data element inessential to the function of the display device 400 or the device in which the display device is implemented, etc.) can be assigned a low, in particular the lowest, priority.

[0103] Changing the data content 450 displayed by the optical display 402 via the display control can involve displaying data elements 452 and 454 in the low-damage or damage-free area 462 of the optical display 402, which exhibits no or only minor damage, depending on the respective priority assigned to the data elements 452, 454, and 456. Initially, only the at least one data element 452 with the highest priority is displayed in the low-damage area 462 of the optical display 402. If further sub-areas are available in the low-damage area 462 of the optical display 402, the at least one further data element 454 with the second-highest priority can be displayed (and so on).Data elements 456 that are no longer displayed in the damage-free area 462 of the optical display 402 (due to space constraints and especially due to priority) can be omitted entirely or displayed in the damage area of ​​the main damage position 460.

[0104] The Figure 5 Figure 1 shows a diagram of an embodiment of a method according to the present invention. The method serves to detect damage to an optical display of a display device, for example a display device according to the following: Figure 2 , 3a , 3b , 4a , 4b , 4c and / or 4d.

[0105] In step 501, a (continuous) detection of an emanating light intensity, caused essentially by the display illumination, is carried out by at least one light sensor arranged on a narrow side of a transparent protective screen of the optical display, as already described.

[0106] In a parallel step 503, the control signal can be provided, which is present at a display illumination of the optical display during the detection of the light intensity, as already described.

[0107] In step 505, a detection of damage to the transparent protective screen is carried out by an analysis module, based on the detected light intensity and the control signal, as already described.

[0108] Optionally, in step 507, a degree of damage to the detected damage to the transparent protective screen and / or a main damage location can be determined, as already described.

[0109] Optionally, in step 509, the data content displayed by the optical display can be changed by controlling the display backlight and / or the display layer arrangement, based at least on the determined main damage position, as already described.

[0110] Preferably, upon detection of damage to the transparent protective screen in step 511, a communication module can be used to send a damage message as previously described.

[0111] The Figure 6Figure 1 shows a schematic view of an embodiment of a ticket vending machine 620 according to the present invention, together with a further embodiment of a display device 600 according to the present invention. To avoid repetition, only the differences from the previous embodiments are explained below, and otherwise reference is made to the descriptions, for example, of the Figures 2 to 5 referred.

[0112] The ticket machine 620, for example for parking tickets or travel tickets, includes, in addition to at least one display device 600, one or more ticket processing modules 668, such as a ticket generation module, a ticket settlement module, a ticket issuance module, a ticket validation module and / or the like.

[0113] The optical display 602 (e.g., an LCD screen) of the display device 600 comprises a display illumination 606 in the form of a backlight, a display layer arrangement 604, a transparent protective screen 608, and a display controller 612. The display controller 612 is specifically configured to control the display illumination 606 with a control signal and to control the display layer arrangement 604 with a display control signal.

[0114] The optical display 602 can be a touch display, so that interaction between a user and the ticket machine 620, in particular the at least one ticket processing module 668, is possible, for example to purchase and / or pay for a ticket.

[0115] Furthermore, the display device 600 comprises a sensor arrangement 638 with at least two light sensors 626, 666. The display device 600 also includes an analysis module 636 and, in particular, a communication module 670. The communication module 670 is configured, in particular, to send a damage notification upon detection of damage to the transparent protective screen 608, especially via a communication network (not shown) to a central unit (not shown). The central unit (e.g., a cloud, one or more servers, etc.) can be configured to initiate a repair of a damaged protective screen 608, in particular a replacement of this protective screen 608.

[0116] The Figure 7aFigure 1 shows exemplary signal waveforms of an intensity signal 770 from a light sensor of a display device according to the present invention and a control signal 772 (in particular a PWM signal) of the display device in an undamaged state of the transparent protective screen. As can be deduced from the maximum amplitude of the (light) intensity signal 770, the light sensor detects only a low light intensity. Together with the control signal 772, the analysis module can, in particular, determine that the transparent protective screen is undamaged.

[0117] The Figure 7bFigure 1 shows exemplary signal waveforms of an intensity signal 770 of a first light sensor of a display device according to the present invention and a control signal 772 (in particular a PWM signal) of the display device in a damaged state of the transparent protective screen. As can be deduced from the maximum amplitude of the (light) intensity signal 770, the light sensor detects a high light intensity (in particular due to the described changed reflection behavior of the transparent protective screen as a result of the damage). Together with the control signal 772, which is unchanged, especially compared to the Figure 7a The analysis module can specifically determine that the transparent protective screen is damaged. In other words, damage can be detected.

[0118] The Figure 7cFigure 1 shows exemplary signal waveforms of an intensity signal 770 from a second light sensor of a display device according to the present invention and a control signal 772 (in particular a PWM signal) of the display device in a damaged state of the transparent protective screen. As can be deduced from the maximum amplitude of the (light) intensity signal 770, the light sensor detects a high light intensity (in particular due to the described changed reflection behavior of the transparent protective screen as a result of the damage). Together with the control signal 772, which is unchanged, especially compared to the Figure 7a The analysis module can specifically determine that the transparent protective screen is damaged. In other words, damage can be detected.

[0119] The difference between the Figure 7b and 7cThe most important point is that the maximum amplitude of the intensity signal is 770 in the Figure 7c is less than the maximum amplitude of the intensity signal 770 in the Figure 7b The analysis module can determine, in particular, that the distance between the first light sensor of the display device and the main damage location is less than the distance between the second light sensor of the display device and the main damage location. Since the respective sensor positions of the first and second light sensors on the transparent protective screen are known to the analysis module, it can determine the main damage location from the different maximum amplitudes of the intensity signals, as already described.

[0120] In summary, it has been established that a pane of glass or similar material is largely transparent to visible light. Only a small portion of the light incident perpendicular to the plane of the pane is reflected towards the edge due to scattering within the pane.

[0121] This transmissive property of a glass pane changes when it is damaged, such as when it breaks. At the fracture edges within the glass pane, more light is coupled out towards the edge or narrow side due to reflection and additional scattering within the plane of the pane. This change in luminous flux can be detected at the edge or narrow side of the glass pane using at least one optical sensor, such as a photodiode or phototransistor, and / or similar device.

[0122] The display's own backlighting, e.g., LED backlighting, is used as the light source. The evaluation electronics, in the form of the analysis module, can be synchronized with the control of the display backlighting to be less sensitive to interference from ambient light by differentially measuring the light intensity signals. Reference symbol list:

[0123] 100 Display device 102 Display 104 Display layer arrangement 106 Display illumination 108 Protective screen 110 Front 112 Display control 114 Narrow side 116 Narrow side 118 Light 120 Ticket machine 192 Evaluation module 194 Sensor light receiver 196 Sensor light source 198 Sensor arrangement 200 Display device 202 Display 206 Display illumination 208 Protective screen 212 Display control 214 Narrow side 216 Narrow side 218 Light 226 Light sensor 228 Front 230 Back 232 Light 234 Damage 236 Analysis module 238 Light sensor arrangement 300 Display device 302 Display 304 Display layer arrangement 306 Display illumination 308 Protective screen 314 Narrow side 316 Narrow side 326 Light sensor 328 Front 330 Back 340 Narrow side 342 Narrow side 344 Mounting frame 346 Reflective layer 400 Display device 402 Display 408 Protective screen 450 Data content 452 Data element 454 Data element 456 Data element 458 Screen surface 460 Main damage position 461 Grid subarea 462 Damage-free area 463 Grid subarea464 Grid 465 Window 501 Step 503 Step 505 Step 507 Step 509 Step 511 Step 600 Display Device 602 Display 604 Display Layer Arrangement 606 Display Illumination 612 Display Control 620 Ticket Machine 626 Light Sensor 636 Analysis Module 638 Sensor Arrangement 666 Light Sensor 668 Ticket Processing Module 670 Communication Module 770 Intensity Signal 772 Control Signal

Claims

1. Display device (200, 300, 400, 600), comprising: - at least one optical display (202, 302, 402, 602) with a display illumination (206, 306, 606) controllable by a display control (212, 612) with a control signal and a transparent protective screen (208, 308, 408, 608), - a light sensor arrangement (238, 638) with at least one light sensor (226, 326, 626, 666) arranged on a narrow side (214, 216, 314, 316, 340, 342, 614, 616) of the transparent protective screen (208, 308, 408, 608), - wherein the at least one light sensor (226, 326, 626, 666) is configured to detect the light intensity emanating from the narrow side (214, 216, 314, 316, 340, 342, 614, 616) and caused essentially by the display illumination (206, 306, 606), and - an analysis module (236, 636), configured at least to detect damage to the transparent protective screen (208, 308, 408, 608), based on the detected light intensity and the control signal,that is present at the display illumination (206, 306, 606) during the measurement of the light intensity.

2. Display device (200, 300, 400, 600) according to claim 1, characterized by the fact that - the light sensor arrangement (238, 638) as light sensor source includes only the display illumination (206, 306, 606).

3. Display device (200, 300, 400, 600) according to one of the preceding claims, characterized by the fact that - the analysis module (236, 636) is set up to detect damage to the transparent protective screen (208, 308, 408, 608) by detecting a minimum change in the detected light intensity with an unchanged control signal.

4. Display device (200, 300, 400, 600) according to claim 3, characterized by the fact that- the analysis module (236, 636) is configured to determine, as a minimum change, a dynamic minimum change based on the control signal applied to the display illumination (206, 306, 606) during the detection of the light intensity, and - the analysis module (236, 636) is configured to detect damage to the transparent protective screen (208, 308, 408, 608) based on the dynamic minimum change and the detected light intensity.

5. Display device (200, 300, 400, 600) according to one of the preceding claims, characterized by the fact that - the analysis module (236, 636) is set up to determine a difference between a maximum of the control signal and a maximum of the detected light intensity, and - the analysis module (236, 636) is set up to determine a degree of damage of the detected damage to the transparent protective disc (208, 308, 408, 608), based on the determined difference.

6. Display device (200, 300, 400, 600) according to one of the preceding claims, characterized by the fact that - the light sensor arrangement (238, 638) comprises at least two light sensors (226, 326, 626, 666), - wherein the at least two light sensors (226, 326, 626, 666) are spaced apart from each other, preferably on two different narrow sides (214, 216, 314, 316, 340, 342, 614, 616) of the transparent protective screen (208, 308, 408, 608).

7. Display device (200, 300, 400, 600) according to one of the preceding claims, characterized by the fact that- the transparent protective screen (208, 308, 408, 608) has a substantially rectangular basic shape, - wherein at least one light sensor (226, 326, 626, 666) is arranged on at least three of the four narrow sides (214, 216, 314, 316, 340, 342, 614, 616) of the transparent protective screen (208, 308, 408, 608), preferably on all four narrow sides (214, 216, 314, 316, 340, 342, 614, 616) of the transparent protective screen (208, 308, 408, 608).

8. Display device (200, 300, 400, 600) according to claim 6 or 7, characterized by the fact that - the at least two light sensors (226, 326, 626, 666) are each configured to provide a respective light intensity signal, and - the analysis module (236, 636) is configured to determine a main damage position, based at least on the respective light intensity of the two light intensity signals.

9. Display device (200, 300, 400, 600) according to claim 8, characterized by the fact that- the display device (200, 300, 400, 600) includes the display control (212, 612), and - the display control (212, 612) is configured to change the data content displayed by the optical display by controlling the display illumination (206, 306, 606) and / or a display layer arrangement, based on the determined principal damage position.

10. Display device (200, 300, 400, 600) according to one of the preceding claims, characterized by the fact that - the display device (200, 300, 400, 600) includes the display control (212, 612), and - the display control (212, 612) is configured to control the display illumination (206, 306, 606) with a predefined test control signal during a predefined test duration, - wherein the analysis module (236, 636) is configured at least to detect damage to the transparent protective screen (208, 308, 408, 608) based on the light intensity detected during the test duration and the test control signal.

11. Display device (200, 300, 400, 600) according to one of the preceding claims, characterized by the fact that - at least on part of the narrow side areas of the transparent protective disc (208, 308, 408, 608) a reflective layer (346) is arranged.

12. Display device (200, 300, 400, 600) according to claim 12, characterized by the fact that - the display device (200, 300, 400, 600) comprises a retaining frame (344) designed to hold the transparent protective screen (208, 308, 408, 608), - wherein the reflective layer (346) is attached to the retaining frame (344) such that a reflective layer (346) is arranged at least on the part of the narrow side areas of the transparent protective screen (208, 308, 408, 608).

13. Display device (200, 300, 400, 600) according to one of the preceding claims, characterized by the fact that- which is surrounded by at least one light sensor (226, 326, 626, 666) from the narrow side (214, 216, 314, 316, 340, 342, 614, 616) of the transparent protective disc (208, 308, 408, 608) and an opaque encapsulation.

14. Method for detecting damage to an optical display (202, 302, 402, 602) of a display device (200, 300, 400, 600), in particular a display device (200, 300, 400, 600) according to one of the preceding claims, comprising: - detecting, by means of at least one light sensor (226, 326, 626, 666) arranged on a narrow side of a transparent protective screen (208, 308, 408, 608) of the optical display (202, 302, 402, 602), an emitted light intensity caused essentially by the display illumination (206, 306, 606), and - detecting, by means of an analysis module (236, 636), damage to the transparent protective screen (208, 308, 408, 608), based on the detected light intensity and a control signal that is applied to a display illumination (206, 306, 606) of the optical display (202, 302, 402, 602) during the detection of the light intensity.

15. Ticket vending machine (620), comprising: - at least one ticket processing module (668), and - at least one display device (200, 300, 400, 600) according to any one of the preceding claims 1 to 13.

Images