Ballistic protection panel

Abstract

The invention relates to a ballistic protective plate (10) with a protective layer (14) made of structural ceramic, wherein a transparent glaze (16, 18) is applied to and bonded with the structural ceramic on a first side (15) of the structural ceramic and / or on a second side (17) of the structural ceramic facing away from the first side (15), wherein the transparent glaze (16, 18) covers at least the majority of the respective side (15, 17) of the structural ceramic, wherein the transparent glaze (16, 18) has side edges (20, 22) which are exposed at least partially in such a way that light striking one of the side edges (20) can pass through the transparent glaze (16, 18) along a direction of radiation (S) and exit the transparent glaze (16, 18) at an opposite side edge (22).A testing device (100), a test device (80) and a method for crack testing of a ballistic protective plate (10) are specified.

Description

[0001] The invention relates to a ballistic protective plate with a protective layer made at least of structural ceramic. The invention further relates to a testing device for crack testing of a ballistic protective plate. In addition, the invention relates to a set comprising such a ballistic protective plate and such a testing device, as well as a method for crack testing of a ballistic protective plate.

[0002] Ballistic protective plates are known from the prior art, for example as vehicle protection for official or military vehicles or as body protection for police or military units, e.g. on protective vests ("bulletproof vests"). Such protective plates, if intact, are capable of stopping projectiles up to a certain caliber or at least slowing them down to such an extent that a person protected by the protective plate(s) who is shot at has a significantly higher chance of survival than without the protective plate(s).

[0003] For a ballistic plate to provide its protective function, it must be intact and undamaged. Even minor damage, such as cracks, can significantly impair its protective effect. However, the user has no way of knowing whether the plate they are using is functioning correctly. Verifying the plate's proper function at the deployment site is usually very difficult, especially since the impact of previous uses, transport, and storage on the plate's protective effectiveness is unclear.

[0004] Several methods are generally available for functionally testing a protective plate. One option would be X-ray testing. However, this method is both time-consuming and expensive, and is usually not feasible at the deployment site. A (destructive) test by firing, with a probability assessment of the protective plate's effectiveness, is also conceivable. This might be feasible at the deployment site, but it only provides a statistical indication and does not allow for a concrete statement about the protective effect of a (non-tested) protective plate. Furthermore, this method consumes protective plates for testing purposes, which are destroyed during the test and therefore no longer usable.

[0005] Other methods for testing a protective plate include RFID, piezoelectric transducer, resistance measurement, automated image analysis, acoustics, or thermal imaging. These methods are comparatively complex from a technical standpoint and are both costly and time-consuming.

[0006] US patent 2012 / 0222543 A1 discloses an armor system with cube-shaped modules for military vehicles. The modules have opaque outer surfaces made of protective material, with transparent armor plates arranged side by side inside. The module features a self-diagnostic damage detection system consisting of lights and photoreceptors arranged along the edges of the plates. If one of the armor plates is damaged, the light from the lights is reflected, thus reducing the light transmission to the photoreceptors. This allows for continuous monitoring of the armor's condition without having to open the module or remove it from the vehicle. However, such a module has a complex structure and is quite heavy.

[0007] The invention is based on the objective of determining, using structurally simple and cost-effective means, whether a ballistic protective plate with a protective layer of structural ceramic is free of defects. It is desirable to be able to determine, simply and cost-effectively, preferably also at the point of use, whether a crack is present in the structural ceramic of the ballistic protective plate that impairs its protective effect (crack testing).

[0008] The invention solves this problem with a ballistic protective plate having the features of claim 1.

[0009] The ballistic protective plate has a (ballistic) protective layer made of at least a structural ceramic (structural ceramic layer). A transparent glaze is applied to the structural ceramic on one side (e.g., the top) and / or on a second side (e.g., the underside) facing away from the first side, and is bonded to the structural ceramic. The transparent glaze covers at least the majority of the respective side of the structural ceramic (the covered first side or second side) (i.e., more than 50% of the surface area of ​​the first side or second side).

[0010] The ballistic protective plate has a light coupling device and a light coupling device, which are optically coupled to the transparent glaze in such a way that light coupled into the transparent glaze at the light coupling device can pass through the transparent glaze and strike the light coupling device.

[0011] In this way, a simple crack test can be performed. The applied transparent glaze provides the basis for examining the condition of the structural ceramic using light. Transparent glaze has the advantage of being translucent. Light can enter the glaze at one point (light coupling device) and exit at another (light coupling device). The refractive index of the transparent glaze is not uniformly homogeneous, as it crystallizes in an amorphous structure. Because the transparent glaze is firmly bonded to the structural ceramic, any damage to the structural ceramic, such as cracking, will also result in crack structures. This can lead to a different refractive index in the area of ​​the crack structures (damaged area) compared to undamaged transparent glaze (principle of dispersion of incident light).When light passing through the transparent glaze encounters cracks, it alters the characteristics of the light reaching the light coupling device, for example, by changing the refractive index (compared to undamaged transparent glaze) and / or the light intensity (altered light properties). One or more of these altered light properties (intensity, wavelength, spectrum, etc.) can be detected using appropriate measuring devices.

[0012] The ballistic protection plate is designed and intended for personal or vehicle protection. In particular, the ballistic protection plate can be designed as a (portable) insert plate for protective clothing such as a ballistic vest.

[0013] The transparent glaze covers the first side or the second side of the structural ceramic to at least 50-100%, preferably to at least 70-100%, more preferably to at least 80-100%, and in particular completely.

[0014] As explained above, light can be coupled into, or enter, the transparent glaze at the light coupling device. At the light extraction device, light can exit the transparent glaze, or in other words, pass from the transparent glaze into the light extraction device. The transparent glaze can have multiple edges, and the light coupling device and / or the light extraction device can each be optically coupled to one of these edges. Optionally, the light coupling device and / or the light extraction device can each be attached to and / or fixed to the respective edge.

[0015] As already indicated, the structural ceramic has a top surface (threat side or "strike face") and a bottom surface facing away from it (protective side or shielding side). The top and bottom surfaces can be connected by a cladding surface, which can be formed from several sides. The structural ceramic can have a substantially cuboid shape or a convex shape (flat or curved shielding plate). In the case of a convex shape, the top surface can have a (preferably convex) convex shape and the bottom surface a (preferably concave) convex shape. The structural ceramic can have a thickness of at least 3 mm and preferably 3–15 mm, more preferably 6–12 mm (distance or mean distance between top and bottom surfaces).In this context, structural ceramics are understood to be ceramics that are able to withstand mechanical loads (tensile and compressive stresses, bending moments, etc.) (sometimes also referred to as industrial or engineering ceramics).

[0016] The construction of ceramics with a transparent glaze is already widespread in silicate ceramics, so the manufacturing technology is well-established. The materials exhibit similar property profiles and undergo a sintering process (or sinter firing) and a glaze firing during production. Glaze layers can generally be applied in thicknesses ranging from a few micrometers to several millimeters.

[0017] The first and / or second side, to which a transparent glaze is applied, can each be designed as the surface with the largest area of ​​the structural ceramic (the body side of the structural ceramic with the largest area). For example, aluminum oxide (Al₂O₃), silicon carbide (SiC), or boron carbide (B₄C) can be used as the ceramic material in the structural ceramic. Infiltrated materials can also be used, in particular silicon-infiltrated silicon carbide, silicon-infiltrated boron carbide, or a silicon-infiltrated mixture of silicon carbide and boron carbide.

[0018] As already indicated, the transparent glaze can have several edges connecting a base surface (facing the structural ceramic) and a top surface (facing away from the structural ceramic) of the transparent glaze. The edges of the transparent glaze can be oriented in the same direction as the surfaces of the structural ceramic. The transparent glaze can have a substantially cuboid or convex shape (corresponding to the structural ceramic it supports). The transparent glaze can have a thickness of 0.005 mm to 2 mm, preferably 0.1 mm to 1 mm (distance or average distance between the base and top surfaces of the transparent glaze).

[0019] If a transparent glaze is applied to only one side of the textured ceramic, this results in a comparatively simple structure with a small number of components. If a transparent glaze is applied to both sides of the textured ceramic, defects such as cracks can also be detected that only border one of the two transparent glazes and do not extend across the entire thickness (distance between the first and second sides of the textured ceramic).

[0020] Advantageously, the light coupling device and / or the light coupling device can each have a mechanical interface. This facilitates coupling of a light source for emitting light (e.g., at a first side edge) or a photoreceptor for receiving light (e.g., at the same or an opposite side edge). The mechanical interface can be designed to prevent the ingress of light from the outside (external light) or the escape of light to the outside (unintentionally escaped light), for example, by a sleeve enclosing the light coupling device and / or the light coupling device. A protective cap, preferably capped securely and / or reversibly openable and closeable, can be provided on the light coupling device and / or the light coupling device to protect against environmental influences. The mechanical interface can, for example, be...It may be designed as a connector (socket or plug) that facilitates coupling of the light source or the photoreceptor. The light source and the photoreceptor can each be designed to complement the mechanical interface, e.g., as a connector counterpart (plug or socket). Optionally, the light source and the photoreceptor can be arranged together in a single connector counterpart (plug or socket).

[0021] Advantageously, the light coupling device and / or the light output device can each include an optical element, in particular a lens. This allows light incident on the light coupling device, e.g., from a light source, and light exiting the light output device, e.g., for a photoreceptor, to be influenced accordingly, for example, by focusing or diffusion. For its protection, the optical element can be arranged within the mechanical interface or, in other words, surrounded by it. This is advantageous if the light source is not permanently connected to the light coupling device and / or the photoreceptor is not permanently connected to the light output device (e.g., in the case of external arrangement of the light source and photoreceptor).

[0022] In a preferred embodiment, the light coupling device can include a light source, in particular an LED. Light beams can be selectively introduced into the transparent glaze by means of the light source. An LED as a light source has low energy consumption, thus facilitating mobile use (power supply via batteries or rechargeable batteries). This allows testing to be carried out with low energy consumption and is safe for the operator. Alternatively or additionally, the light coupling device can include a light receptor, in particular a photodiode. This allows the light intensity of the light incident on the light coupling device to be determined. Photodiodes are capable of converting detected light into voltage or current. A photodiode configured to receive information transmitted via light can also be used in this case.

[0023] The light source and / or the photoreceptor can optionally be permanently connected to the light coupling device or the light coupling device. This facilitates a design of the ballistic protective plate in which the light source and the photoreceptor are permanently attached to or integrated into the protective plate. In this case, a connecting cable can be routed from the protective plate to enable power supply and / or transmission of measurement signals.

[0024] Alternatively, the light source and / or the photoreceptor can be reversibly and detachably connected to the light coupling device or the light coupling device. Besides simplifying the design, this contributes to a lower weight of the protective plate. In this configuration, the light source and the photoreceptor would only be connected to the light coupling device or the light coupling device for testing purposes. Thus, only the light coupling device and the light coupling device, specifically those with their mechanical interfaces and / or optical elements, would remain permanently attached to the protective plate.

[0025] In a preferred embodiment, the light source and / or the photoreceptor can be coupled to or connected to an electrical or electronic test device. The test device is configured, in particular, to determine one or more light properties (e.g., intensity, wavelength, spectrum, etc.) of the light incident on the photoreceptor when the light source is activated. This allows the determination of whether one or more cracks are present in the transparent glaze and thus also in the structural ceramic, which could lead to degradation or loss of the protective effect. The test device can be designed as an external unit relative to the protective plate, which can be reversibly coupled to the light source and the photoreceptor. This contributes to a compact design and low weight of the protective plate, since the test device is only coupled to the light source and the photoreceptor for testing purposes.Alternatively, the test setup can be permanently attached to the protective plate and coupled to the light source and the photoreceptor. This simplifies handling and enables particularly fast testing, as the test setup does not need to be carried separately and connected to the light source and photoreceptor for testing purposes. The protective plate incorporates the test setup, which, depending on its design, can form either a functional unit (test setup designed as an external unit in relation to the protective plate) or a physical unit (test setup connected to the protective plate).

[0026] Specifically, the test setup can be configured to determine whether, with the light source activated, one or more light properties (intensity, wavelength, spectrum, etc.) of the light incident on the photoreceptor exceed or fall below a threshold value, in particular a threshold value of a light property, e.g., a light intensity threshold. The test setup can further be configured to output a first signal when the threshold is exceeded (protective plate or structural ceramic good, e.g., green signal), and a second signal when the threshold is not met (protective plate or structural ceramic not good, e.g., red signal). The test setup can include an electrical or electronic output device for outputting the first and second signals as electrical or electronic signals.The test setup may alternatively or additionally include an optical output device for signal output, wherein the output device may comprise one or more LEDs (e.g., a red LED for outputting the red signal and a green LED for outputting the green signal) and / or a display. Furthermore, the test setup may include an electrical connection device, e.g., a connector, for connecting the light source and the photoreceptor.

[0027] In a preferred embodiment, a reflective layer can be applied to the transparent glaze on both the side facing away from and / or the side facing the structural ceramic. This contributes to higher measurement accuracy, as the light emitted by the light source is captured by the photoreceptor to the greatest extent possible (light loss at the base layer and / or the top layer of the transparent glaze is largely avoided). To allow light to be coupled in and / or out at the side edges of the transparent glaze, the side edges at the light coupling device and the light coupling device should not be covered by a reflective layer. The reflective layer can be designed as a film, as a (preferably opaque) cladding glass, or as a combination of film and cladding glass.Specifically, the reflective layer can be formed as an adhered or laminated film, or applied to the transparent glaze by spraying, screen printing, or vapor deposition.

[0028] Advantageously, a splinter protection layer can be applied to the transparent glaze on the side facing away from the structural ceramic (the top side, or threat side). This splinter protection layer can capture splinters deflected forward (towards the threat side) by the structural ceramic, thus limiting their further spread. If a reflective film is provided on this side of the transparent glaze, it can be positioned between the transparent glaze and the splinter protection layer.

[0029] It is advantageous to apply a reinforcing layer ("backing") to the transparent glaze on the side facing away from the structural ceramic (the underside or protective side). This allows splinters that break off from the structural ceramic (towards the back, i.e., towards the protective side) or penetrate it to be caught. The reinforcing layer consists of a material with a comparatively high tensile strength. In particular, the reinforcing layer can be made of (consolidated) fiber-reinforced composites, e.g., aramid and / or polyethylene. If a reflective film is provided on this side of the transparent glaze, it can be positioned between the transparent glaze and the reinforcing layer.

[0030] In a preferred embodiment, the structural ceramic and the at least one transparent glaze, preferably also the splinter protection layer and / or the reinforcing layer, can be encased by a cover layer. This protects the components of the protective plate from environmental influences. The cover layer preferably surrounds the encased components on all sides. The cover layer can be made of different materials. The cover layer forms an encasement of the components. Only the light coupling device and the light output device, or a connecting cable attached thereto, may protrude from the cover layer or, in other words, be routed through a corresponding opening in the cover layer.

[0031] Advantageously, a calibration channel can be provided that optically couples the light coupling device and the light output device directly to each other, particularly bypassing the transparent glaze. This allows light properties to be determined with higher accuracy, since calibration can be performed prior to a measurement or between several measurements (determining the light properties incident on the light output device while bypassing the transparent glaze). For this purpose, the calibration channel establishes an optical coupling between the light source and the photoreceptor, in particular by means of a line of sight (in a gas such as air) or by means of an optical fiber.

[0032] In other words, a fixed connection can exist between the light coupling device and the light coupling device, for example, in the form of an optical fiber. The connection, e.g., a plug, can then be designed so that a second channel in the plug compares the transmission parameter via the optical fiber with the transmission parameter in the transparent glaze and thus measures a relative value, or a drop in performance. This would have the advantage of detecting incorrect or poor connections, because then both channels would be equally poor, which is unlikely, and fluctuating input and output powers would be compensated for. In principle, this can be used for self-calibration during ongoing measurement.

[0033] Specifically, the light injection device and the light extraction device can each be attached and / or fixed to a side edge of the transparent glaze. This allows light injection and light extraction to occur at a defined point.

[0034] Advantageously, the light coupling device can be attached to a first side edge of the transparent glaze, and the light coupling device can be attached to a second side edge of the transparent glaze, particularly to a side edge opposite the first. This allows light to pass through the transparent glaze along a beam path or direction S from the first side edge to the second (possibly opposite) side edge. Thus, the light largely or even completely passes through the transparent glaze, allowing any damage, such as one or more cracks, to be detected.

[0035] Optionally, a further light coupling device can be attached to a third side edge, and a further light extraction device to a fourth side edge, particularly one opposite the third side edge. This allows for multi-directional testing of the transparent glaze or provides a redundant testing option. The additional light coupling device can be constructed analogously to the (first) light coupling device. The additional light extraction device can also be constructed analogously to the (first) light extraction device.

[0036] In an alternative design, the light coupling device and the light extraction device can both be arranged on the same side edge of the transparent glaze. This simplifies the design of the protective plate, as the light coupling device and the light extraction device, as well as any interfaces or connecting lines, can be located on the same side edge of the transparent glaze. This means that connecting lines only need to be routed from one side edge, or the interfaces only need to be accessible from one side edge of the transparent glaze. This contributes to a simplified design of an enveloping protective layer, such as a top layer of the protective plate. The light coupling device and the light extraction device can share a common mechanical interface and a common optical element (instead of separate mechanical interfaces and optical elements).

[0037] Advantageously, a light return channel can be provided, configured to return light coupled in by the light coupling device, which has passed through the transparent glaze, from the second side edge to the side edge where the light coupling device and the light extraction device are located (e.g., the first side edge). This facilitates the design of the protective plate due to the arrangement of the light coupling device and the light extraction device on the same side edge of the transparent glaze (connections or accessibility are only required on one side edge). The light return channel is light-guiding (an additional light-guiding channel). The light return channel establishes an optical coupling between the second (opposite) side edge and the light extraction device (first side edge).

[0038] In one possible embodiment, the light return channel can be arranged outside the transparent glaze (external light return channel, e.g., as an external light guide). Alternatively, the light return channel can be arranged inside the transparent glaze, with a mirror or reflective element positioned at the second side edge, so that the light (coupled at the light coupling device and reaching the second side edge) is returned within the transparent glaze to the first side edge (light coupling device).

[0039] In an advantageous embodiment, the light coupling device and the light coupling device can be combined into a single unit for transmitting and receiving a pulsed light signal. This contributes to a more compact design and may reduce the number of connections required on the protective plate. The unit can be a transceiver that is set up and / or configured (as a "light coupling device") to transmit and receive a pulsed light signal. The transceiver can be located on the first side edge. On the second side edge, a reflective element can be arranged on or in the transparent glaze, or a reflective treatment can be formed on the transparent glaze (mirror, reflective film, mirrored coating, or total internal reflection).

[0040] One function can be such that the pulsed light signal is emitted by the unit (transceiver) at the first edge, enters the transparent glaze, and passes through the glaze towards the second edge (outbound path). At the second edge, the light or pulsed light signal is reflected (by means of a reflective element or a reflective treatment), so that the reflected light or light signal passes through the transparent glaze from the second edge towards the first edge (return path). The light or pulsed light signal is then detected by the unit (transceiver) at the first edge. The unit (transceiver) that combines the light coupling device and the light coupling device can be arranged in an electrical or electronic connector.

[0041] In other words, the input light power can be pulsed. Step-shaped signals can be generated using fast LEDs (light source). If the opposite side (second edge) is reflected as described, a transceiver diode (as in full-duplex measurement) can be used in the same measuring device (unit), requiring only one connection. If the LED and / or the transceiver diode are fast enough, the reflected step can be measured, and from this, the distance of the crack from the coupling side (first edge) can potentially be determined. By varying the color temperature (i.e., the frequency), the type of crack can also be deduced (via propagation time and polarization).

[0042] The aforementioned problem is also solved by a test device with the features of the subordinate claim.

[0043] The test device is designed and / or intended for crack testing of a ballistic protective plate. The ballistic protective plate comprises, in particular, a (ballistic) protective layer made of structural ceramic, and a transparent glaze applied to a first side of the structural ceramic and / or to a second side of the structural ceramic, each with at least partially exposed side edges. The ballistic protective plate (to be tested) may, in particular, have one or more of the aspects described above.

[0044] The test device includes: an electrical energy source, an electrical connection device for connecting a light source and a photoreceptor, an evaluation device powered by the energy source and electrically and / or electronically coupled to the connection device for determining one or more light properties detected by the photoreceptor (intensity, wavelength, spectrum, etc.).

[0045] This simply constructed testing device allows for crack testing of a ballistic protective plate, even shortly before deployment at or near the deployment site. This enables a quick and easy verification of the ballistic protective plate's integrity and its ability to protect personnel and / or equipment.

[0046] If the evaluation unit detects that one or more of the light properties detected by the connected photoreceptor, e.g., light intensity, falls below a threshold value, it can be assumed that the structural ceramic has damage such as cracks. Conversely, if the evaluation unit detects that one or more of the light properties detected by the connected photoreceptor, e.g., light intensity, exceeds a threshold value, it can be assumed that the structural ceramic is intact.

[0047] The connection device is designed in such a way that it can be electrically coupled to a connecting cable of the light coupling device (light source) and the light coupling device (light receptor).

[0048] The evaluation unit is configured to determine whether, with an active light source (electrically connected to the connection device), one of the light properties, e.g., the intensity, of the light incident on the photoreceptor (electrically connected to the connection device) exceeds or falls below a threshold value, in particular a light intensity threshold. The evaluation unit can then output a signal accordingly.

[0049] As already mentioned, a light source and a photoreceptor can be provided, each electrically connected to the connection device via a connecting cable. This allows for easy connection and disconnection of the light source and / or photoreceptor to the connection device. The connecting cable can be electrically coupled to the light source and photoreceptor at one end and have an electrical connector at the other end that can be connected to the connection device (complementary configuration). The light source and photoreceptor are each configured such that they can be coupled to the transparent glaze at the light coupling device and the light coupling device, for example, at their mechanical interface.

[0050] In a preferred embodiment, an additional light source and photoreceptor can be provided, which are also connected to the connection device via the connecting cable. This allows the structural ceramic to be tested in two different directions or provides a redundant testing option. This way, crack structures can be detected even if they extend along the (first) beam direction (connecting line between the first light source and the first photoreceptor). The connection device and / or the evaluation device are configured such that the first light source and photoreceptor, as well as the additional light source and photoreceptor, are activated sequentially (illumination and measurement of the light intensity occur one after the other in the different orientations).

[0051] Advantageously, an output device interacting with the evaluation unit can be provided, configured such that an optical and / or acoustic signal is output (at least when) the light source is active and one of the light properties (intensity, wavelength, spectrum, etc.) of the light incident on the photoreceptor falls below a threshold value, in particular a light intensity threshold. This allows an operator to be informed that the tested protective plate has damage, such as a crack. The output device can be electrically and / or electronically connected to the evaluation unit, for example, to one or more outputs of the evaluation unit.

[0052] The output device for optical signal output can suitably include a display, an indicator, and / or at least one or more LEDs (e.g., as a red-green indicator). This allows appropriate visual feedback on the test result (protective plate intact or not intact) to be provided to the operator.

[0053] Alternatively or additionally, the output device for acoustic signal output can include a loudspeaker. This allows for acoustic output. Acoustic signal output alone can be advantageous when generating a visual signal is to be avoided (e.g., darkness near an enemy) or when such a signal is not reliably visible (difficult optical conditions such as dust or fog). A combined visual and acoustic signal output is beneficial for increasing the operator's perception of a signal.

[0054] In a preferred embodiment, a wireless or wired interface (data interface) coupled to the evaluation unit can be provided for transmitting signals from the evaluation unit. This allows determined values ​​or measurement results to be transmitted to an external receiver, in particular a control center.

[0055] The test device may have a housing in which components of the test device are enclosed, in particular the energy source, the evaluation unit, the connection unit and / or the output unit.

[0056] In principle, it is conceivable that the test setup described above in connection with the ballistic protection plate and the test device described here represent alternatives to each other and can therefore be used interchangeably (either the test setup or the test device). However, complementary use is also conceivable. For example, the test setup could be used as a mobile rapid test shortly before deployment, and the test device for more comprehensive testing, e.g., after returning from a mission. The light coupling device and the light coupling device can be configured for connecting, and in particular for simultaneous connection to, the test setup and the test device.

[0057] The testing device is particularly suitable for carrying out the crack testing procedure for a ballistic protective plate, which is described below.

[0058] The measures explained above and / or discussed below can be used to further develop the test device.

[0059] The aforementioned task is also solved by a set comprising a ballistic protective plate with one or more of the aspects described above and a test device with one or more of the aspects described above.

[0060] Regarding the advantages achievable in this way, reference is made to the relevant explanations concerning the ballistic protective plate and the test device. The measures described above and / or discussed below can serve to further develop the test device.

[0061] The aforementioned problem is also solved by a method for crack testing of a ballistic protective plate, in particular a test to determine whether a crack is present in the structural ceramic of the ballistic protective plate. The ballistic protective plate has, in particular, a (ballistic) protective layer made of structural ceramic, a transparent glaze applied to a first side of the structural ceramic and / or to a second side of the structural ceramic, each with at least partially exposed side edges. The ballistic protective plate (to be tested) may, in particular, have one or more of the aspects described above.

[0062] The process includes the following steps: Illuminating a side edge of the transparent glaze so that light striking this side edge can pass through the transparent glaze and exit at the same or an opposite side edge, detecting the light exiting at the same or opposite side edge, and determining whether one or more light properties of the exiting light, e.g., the light intensity, falls below or exceeds a threshold value (e.g., light intensity threshold).

[0063] If it is determined that, for example, the light intensity of the emitted light falls below a threshold value, it can be assumed that the structural ceramic has damage such as cracks. Conversely, if it is determined that, for example, the light intensity of the emitted light exceeds a threshold value, it can be assumed that the structural ceramic is intact, as explained above.

[0064] The threshold(s) mentioned here or above may be known, determined empirically or individually, or determined "live" through calibration (e.g., using the calibration channel described above).

[0065] When light enters an undamaged layer of the transparent glaze, most of it will exit the glaze at the opposite edge or strike the photoreceptor (with known, possibly only moderately altered, light properties). In contrast, if the glaze is cracked, the light will undergo refraction and / or reflection, so that some of the light will be reflected back towards the first edge (the light source), resulting in a greater change in its light properties. Therefore, a photoreceptor, especially a photodiode, will experience a lower current flow and receive less data from the radiation when the glaze is damaged compared to an intact glaze.

[0066] Advantageously, the procedure may optionally include the following additional steps: Illuminating a third, at least partially exposed, side edge of the transparent glaze, so that light striking the third side edge can pass through the transparent glaze and exit the transparent glaze at the third side edge or at a fourth side edge opposite the third side edge (at least partially exposed), detecting the light exiting at the third side edge or the light exiting at the fourth side edge, and determining whether one or more light properties of the exiting light, e.g., the light intensity, fall below or exceed a threshold value.

[0067] This contributes to a higher reliability in detecting damage such as cracks, as damage to the structural ceramic can be detected even if the crack extends along the (first) direction of the light beam. The first and third edges of the transparent glaze are preferably illuminated sequentially, so that the light emitted by the respective light sources does not interfere with each other (and, for example, an intact structural ceramic is not erroneously assumed due to "excessively high" detected light intensities).

[0068] In a preferred embodiment, a signal is emitted at least when one of the light properties of the emitted light, e.g., light intensity, falls below a threshold value. This allows an operator to recognize that the ballistic protective plate or its structural ceramic is damaged.

[0069] Specifically, a first signal can be output if, for example, the light intensity (one of the properties of light) of the emitted light exceeds a threshold (ballistic shield good; e.g., green signal output), and / or a second signal can be output if, for example, the light intensity of the emitted light falls below a threshold (ballistic shield not good; e.g., red signal output). Both the first and second signals can be output as visual signals, e.g., as color-coded signals, particularly as red / green signals as indicated. Alternatively or additionally, outputting the first and second signals as acoustic signals is conceivable. Outputting the first and second signals as electrical or electronic signals is also possible.

[0070] Advantageously, the signal, in particular the first signal and / or the second signal, can be transmitted wirelessly or via a wired connection to an external receiver, especially a control center. This allows an external receiver to be informed about the status of one or more ballistic plates or protective clothing equipped with these plates.

[0071] The method for crack testing of a ballistic protective plate can be carried out in particular with a test device that has one or more of the aspects described above.

[0072] The invention is explained in more detail below with reference to the figures, where identical or functionally equivalent elements are provided with identical reference numerals, possibly only once. The figures show, schematically, Fig. 1 shows an embodiment of a ballistic protective plate in a sectional view; Fig. 2 shows an embodiment of a testing device for crack testing of a ballistic protective plate in a front view; Fig. 3 shows the structural ceramic of the protective plate made of Figure 1 in an enlarged partial view with structural ceramic in intact condition; Fig. 3b the structural ceramic of the protective plate made of Figure 1 in an enlarged partial view with structural ceramic in a non-intact state; Fig. 4 a possible design of the ballistic protective plate made of Figure 1 with integrated light source and integrated photoreceptor; Fig. 5 shows a possible design of the ballistic protective plate made of Figure 1 with integrated test device; Fig. 6a a possible design of the ballistic protective plate made of Figure 1, in which the light coupling device and the light coupling device are arranged on the same side of the protective plate; Fig. 6b the ballistic protective plate made of Figure 6a in an enlarged partial view; and Fig. 7 a possible design of the ballistic protective plate made of Figure 1 , in which the light coupling device and the light coupling device are combined into a single unit for transmitting and receiving a pulsed light signal.

[0073] Figure 1 Figure 1 shows a schematic sectional view of a ballistic protective plate, which is designated overall by the reference numeral 10.

[0074] The ballistic protection plate 10 in this example is designed and / or intended as a protective ballistic insert plate for protective clothing such as a ballistic vest. The protection plate 10 has a first side or threat side 11 ("strike face") and a second side or protection side 12 facing away from the threat. Therefore, the protection plate 10 must be inserted into a pocket of protective clothing in a specific orientation (this is usually determined by the shape of the protection plate).

[0075] The protective plate 10 has a (ballistic) protective layer 14, which consists at least of structural ceramic. For the sake of clarity, the ballistic protective layer 14 and the protective plate 10 are shown with an overall essentially cuboid shape. In reality, however, they can have a convex shape, as explained above (e.g., convex towards the threat side 11 and concave towards the protection side 12).

[0076] In this example, a transparent glaze 16, 18 is applied to the first side 15 of the textured ceramic (top side) and to a second side 17 of the textured ceramic (bottom side), specifically fired onto the ceramic and bonded to it. In this example, the transparent glazes 16, 18 completely cover their respective sides 15, 17 of the textured ceramic. The thickness of the transparent glazes 16, 18 is shown for illustrative purposes only. In reality, they may be significantly thinner (possibly only a few µm thick).

[0077] The transparent glaze 16, 18 each has side edges 20, 22, which are exposed at least partially such that light striking one of the side edges 20 can pass through the transparent glaze 16, 18 along a direction of radiation S in the example and exit at another side edge 22. In principle, the side edges 20, 22 can be oriented differently relative to each other, as described above. In the present example, side edge 20 and side edge 22 are opposite each other.

[0078] A light coupling device 24 is attached to one side edge 20 of the transparent glaze 16, 18. A light extraction device 26 is attached to the opposite side edge 22 of the transparent glaze 16, 18. In this example, the light coupling device 24 and the light extraction device 26 are positioned opposite each other along the beam direction S. The light coupling device 24 and the light extraction device 26 are optically coupled to the transparent glaze 16, 18 such that light coupled into the transparent glaze 16, 18 at the light coupling device 24 can pass through the transparent glaze 16, 18 and strike the light extraction device 26.

[0079] In the example, the light coupling device 24 and the light coupling device 26 each have a mechanical interface 27 and an optical element 28 (see figure). Fig.3aThe mechanical interface 27 can be designed as a connector (element of a plug connection). The optical element 28 can be designed as a lens.

[0080] The light coupling device 24 comprises a light source 30, in particular an LED. The light coupling device 26 comprises a light receptor 32, in particular a photodiode. The light source 30 and the light receptor 32 are electrically connected by a connecting cable 34, which has an electrical connector 36, e.g. a plug, at the end facing away from the light source 30 and the light receptor 32.

[0081] In this example, the light source 30 and the photoreceptor 32 are each reversibly and detachably connected to the light coupling device 24 and the light coupling device 26, respectively. The light source 30 and the photoreceptor 32 can be connected to one of the light coupling devices 24 and one of the light coupling devices 26 for testing the protective plate 10 and then removed again. Only the light coupling devices 24 and the light coupling devices 26 remain permanently attached to the protective plate 10.

[0082] In the example, a reflective layer 38, 40 is applied to the transparent glaze 16, 18 on the side facing away from the structural ceramic and on the side facing the structural ceramic (cf. Figure 3aThe reflective layer 38, 40 can be designed as an adhered film. By means of the reflective layers 38, 40, unwanted light emission laterally to the beam direction S (light loss at a base layer and a top layer of the transparent glaze 16, 18) can be prevented, which improves the measurement accuracy, as explained above.

[0083] On the side exposed to the threat 11, a splinter protection layer 42 is applied to the transparent glaze 16 on the side facing away from the structural ceramic 14. If a reflective film 38 is provided, it is arranged between the transparent glaze 16 and the splinter protection layer 42.

[0084] On the protective side 12, a reinforcing layer 44 is applied to the transparent glaze 18 on the side facing away from the structural ceramic 14 (cf. Fig.1 ). If a reflective film is provided there (not shown), it is positioned between the transparent glaze 18 and the reinforcing layer 44.

[0085] The structural ceramic 14, the transparent glazes 16, 18, including any reflective layers 38, 40, the splinter protection layer 42, and the reinforcing layer 44 are encased by a cover layer 46. In this example, the cover layer 46 surrounds the encased components on all sides. Only the light coupling devices 24 and the light extraction devices 26 protrude from the cover layer 46 and are each guided through a corresponding opening 48, 49 in the cover layer 46.

[0086] As explained above, the light source 30 and the photoreceptor 32 can be connected to a test device 80. The test device 80 is configured to determine one or more light properties, e.g., the intensity, of the light incident on the photoreceptor 32 when the light source 30 is activated. In this example, the test device 80 is designed as an external unit relative to the protective plate 10. The test device 80 can comprise a housing 82, a connection device 84 for the light source 30 and the photoreceptor 32, e.g., a socket connectable to the connector 36, an evaluation element 86, a power source 88, and two LEDs 90, 92.

[0087] The connection device 84, the power source 88, and the LEDs 90 and 92 are electrically and / or electronically coupled to the evaluation element 86 (e.g., a microprocessor with memory). The test device 80 can then output a first signal (protective plate 10 or structural ceramic 14 good, e.g., a green signal via LED 90) when one or more light properties, e.g., the intensity of the light incident on the photoreceptor 32, exceed a threshold value. It can then output a second signal (protective plate 10 or structural ceramic 14 not good, e.g., a red signal via LED 92) when the threshold value is undershot. The test device 80 can be used to perform a rapid test, e.g., immediately before the use of protective clothing equipped with the protective plate 10 or several such protective plates 10.

[0088] Figure 2Figure 100 shows a test device 100 for crack testing of a ballistic protective plate 10 in a front view. The protective plate 10 (to be tested) is preferably designed as described above.

[0089] The test device 100 has a housing 102 in which the components of the test device 100 are arranged or enclosed.

[0090] The test device 100 has an electrical energy source 104, through which the components of the test device 100 can be supplied with electrical energy. The energy source 104 can be an electrochemical energy storage device (battery or accumulator), a mains connection, or a combination thereof.

[0091] The test device 100 further comprises an electrical connection device 108 for connecting a light source 30 and a photoreceptor 32 of the protective plate 10. The connection device 108 is designed in this case as a connector socket with which the connector 36 can be electrically coupled.

[0092] The test device 10 also includes an evaluation unit 110, powered by the energy source 104 and electrically and / or electronically coupled to the connection device 108, for determining light properties detected by the photoreceptor 32 (connected to the connection device 108), e.g., the light intensity. The evaluation unit 110 is configured to determine whether (with the light source 30 activated) one or more light properties, e.g., the intensity, of the light incident on the photoreceptor 32 exceeds or falls below a threshold value (light intensity threshold). A signal can be output accordingly. The evaluation unit 110 can include a computing unit, e.g., a microcontroller with memory, as explained above.

[0093] As already explained, a light source 30 and a photoreceptor 32 are provided, each electrically connected to a connecting cable 34 for connection to the connection device 108. The connecting cable 34 is electrically coupled at one end to the light source 30 and the photoreceptor 32 and has an electrical connector 36 at the other end, which can be connected to the connection device 108.

[0094] Optionally, an additional light source and a further photoreceptor can be provided, which are also connected to the connection cable 34 for connection to the connection device 108 (not shown). This allows the structural ceramic to be tested in two different directions (first beam direction and second beam direction). This makes it possible to detect crack structures even if they are oriented parallel to one of the beam directions, as explained above. Alternatively, redundant testing is possible.

[0095] In this example, the test device 100 further comprises an output device 112 that interacts with the evaluation device 110. The output device 112 is configured to output an optical and / or acoustic signal when the light source 30 is active and one or more light properties, e.g., the intensity, of the light incident on the photoreceptor 32 falls below a threshold value. The output device 112 is electrically and / or electronically connected to the evaluation device 110, specifically to one or more outputs of the evaluation device 110.

[0096] In the example for optical signal output, output device 112 has a display 114 and two LEDs 115 and 116. The display can show numerical and / or textual information, such as a light intensity value detected at the connection device 108 (e.g., in candela, lumens, or lux). LED 115 can output a first signal (LED 115 lights up) if, for example, the intensity of the light incident on the photoreceptor 32 exceeds a threshold (light intensity threshold) (protective plate 10 good, e.g., green signal). LED 116 can output a second signal (LED 116 lights up) if, for example, the intensity of the light incident on the photoreceptor 32 falls below a threshold (light intensity threshold) (protective plate 10 bad, e.g., red signal). Optionally, the output device 112 can have a loudspeaker for acoustic signal output.

[0097] In this example, the test device 100 also has a wireless interface 118 coupled to the evaluation unit 110 for transmitting signals (wireless connection 140) to an external receiver 150, e.g., a control center, which also has a wireless interface 152. The test device 100 can alternatively or additionally have a wired interface for transmitting signals (not shown).

[0098] The set 200 mentioned above comprises a ballistic protective plate 10 with one or more of the described aspects and a test device 100 with one or more of the described aspects.

[0099] The procedure for crack testing of a ballistic protective plate 10, which can be carried out with the test device 100 or the test equipment 80, proceeds as follows.

[0100] First, the ballistic protective plate 10 and the test device 100 are connected by connecting the connector 36 to the connection device 108, thereby electrically connecting the light source 30 and the photoreceptor 32 to the connection device 108.

[0101] If the test device 80 is used instead of the test device 100, the ballistic protective plate 10 and the test device 80 are connected by connecting the connector 36 to the connection device 84, thereby electrically connecting the light source 30 and the photoreceptor 32 to the connection device 84.

[0102] If not already done, the light source 30 is coupled to the light coupling device 24 and the light receptor 32 is coupled to the light coupling device 26.

[0103] One side edge 20 of the transparent glaze 16 is then illuminated, so that light incident on this side edge 20 passes through the transparent glaze 16 along the direction of the beam S and, in this example, exits the transparent glaze 16 at an opposite side edge 22. The side edge 20 can be illuminated by the light source 30.

[0104] The light exiting at the opposite side edge 22 in this example is then detected. This can be done using the photoreceptor 32.

[0105] The system then determines whether the light emerging from the side edge 22 exceeds or falls below a threshold value of one or more light properties, e.g., a luminous intensity threshold. This can be done using the evaluation unit 110 of the test device 100 or using the evaluation unit 86 of the test device 80.

[0106] Figure 3ashows the protective layer 14 or structural ceramic of the protective plate 10 made of Figure 1 (Enlarged partial view) with applied transparent glaze 16, the structural ceramic being in an intact state. At the light coupling device 24 by means of the coupled light source 30 (for clarity, shown here and in Figure 3b Light coupled at the side edge 20 (shown in the uncoupled state) can pass unhindered through the transparent glaze 16 along the beam direction S and exit the transparent glaze 16 at the opposite side edge 22. The light output device 26 is connected to the coupled light receptor 32 (shown here and in the figure for clarity). Figure 3b The light intensity (shown in the uncoupled state) is comparatively high (as an example of one of the properties of light), since a large proportion of the light emitted by the light source 30 hits the photoreceptor 32.

[0107] Figure 3b Figure 1 shows the protective layer 14 or structural ceramic of the protective plate 10 (enlarged partial view) with applied transparent glaze 16, the structural ceramic being in a non-intact state, as a crack 50 extends through it. The crack 50 extends through both the structural ceramic 14 and the transparent glaze 16.

[0108] Light coupled to the light coupling device 24 at the side edge 20 by means of the light source 30 can initially pass unimpeded through the transparent glaze 16 along the beam direction S and then encounters the crack 50. At the crack 50, the light undergoes refraction and / or reflection, so that part of the light is scattered and / or reflected back towards the light source 30. The light property detected at the light coupling device 26 by means of the photoreceptor 32, e.g., the light intensity, is therefore lower than in undamaged structural ceramic (e.g., detection of lower voltage or lower current at the photoreceptor 32).

[0109] Optionally, a further (third) side edge of the transparent glaze can be illuminated and the emerging light captured at a further opposite side edge (fourth side edge), as explained above (not shown).

[0110] As already indicated, a signal can be output at least when, for example, the light intensity of the light exiting at the (opposite) side edge 22 falls below a threshold value (light intensity threshold). This can be done via the output device 112 of the test device or by one of the LEDs 90, 92 of the test unit 80.

[0111] Specifically, a first signal can be output when the light intensity (as an example of a light property) of the light exiting at side edge 22 exceeds a threshold value. This can be done via the LED 115 of the test device 100 or the LED 90 of the test setup 80, which will illuminate accordingly (protective plate 10 good, e.g., green signal). A second signal can be output when the light intensity (as an example of a light property) of the light exiting at side edge 22 falls below a threshold value. This can be done via the LED 116 of the test device 100 or the LED 92 of the test setup 80, which will illuminate accordingly (protective plate 10 not good, e.g., red signal). Alternatively or additionally, the first and second signals can each be output as an acoustic signal, e.g., via a loudspeaker installed in the test setup 80 or the test device 100 (not shown).Output of the first signal and the second signal as an electrical or electronic signal is also conceivable.

[0112] Optionally, the first signal and / or the second signal can be transmitted to an external receiver 150, in particular to a control center. This can be done via the wireless interface 118 of the test device 100, which is coupled to the evaluation unit 110, whereby the receiver 150 can receive the signals via a wireless interface 152 (as explained above, wired signal transmission is also conceivable).

[0113] Figure 4 shows one possible design of the protective plate 10, which largely corresponds to that associated with the Figure 1 , 3a and 3b The protective plate 10 described corresponds to this, so to avoid repetition, reference is first made to the explanations given there.

[0114] In contrast, in this case the light coupling device 24 and the light coupling device 26, as well as the light source 30 and the photoreceptor 32, are enclosed by the cover layer 46, so that only the connecting lines 34 protrude from the cover layer 46 and are guided through a corresponding opening 48, 49 in the cover layer 46. The light source 30 and the photoreceptor 32 are preferably permanently connected to the light coupling device 24 and the light coupling device 26, respectively.

[0115] Although in Figure 4For the sake of clarity, only the light source 30 and the light receptor 32 are shown, which are connected to the light coupling device 24 and the light coupling device 26 of the transparent glaze 16. If two transparent glazes 16, 18 are provided on the present protective plate 10, a light source 30 and a light receptor 32 can also be provided, which are connected to the light coupling device 24 and the light coupling device 26 of the transparent glaze 18 and are also connected to the connecting line 34.

[0116] Figure 5 shows one possible design of the protective plate 10, which largely corresponds to that associated with the Figure 1 , 3a and 3b The protective plate 10 described corresponds to this, so to avoid repetition, reference is first made to the explanations given there.

[0117] In contrast, in this case not only the light coupling device 24, the light coupling device 26, the light source 30 and the photoreceptor 32 are enclosed by the cover layer 46, but at least the majority of the test device 80 is also enclosed. In this example, only the LEDs 90, 92 of the test device 80 protrude from the cover layer 46.

[0118] If, as shown here, two transparent glazes 16, 18 are present on the protective plate 10, the light source 30 and the photoreceptor 32 are connected to the light coupling device 24 and the light coupling device 26 of both transparent glazes 16, 18. In this configuration, the photoreceptor 32 can be electrically or electronically connected to the test device 80 via the connecting line 34.

[0119] In one possible embodiment, the connecting cable 34 can have a light guide 37. The light guide 37 can form a calibration channel Sc, which optically couples the light coupling device 24 and the light coupling device 26 directly to each other, bypassing the transparent glaze 16, 18, as described above. This enables (self-)calibration and increases the measurement accuracy.

[0120] The Figures 6a and 6b show one possible design of the protective plate 10, which largely corresponds to the one associated with the Figure 1 , 3a and 3b The protective plate 10 described corresponds to this, so to avoid repetition, reference is first made to the explanations given there.

[0121] In contrast, in the present protective plate 10, the light coupling device 24 and the light coupling device 26 are arranged on the same side of the protective plate 10, in this example on the first side edge 20 of the transparent glaze 16. In this example, the light coupling device 24 and the light coupling device 26 share a mechanical interface 27 and an optical element 28 (so to speak, "only one common connection").

[0122] In this example, the light source 30 and the photoreceptor 32 are arranged together in a connector counterpart 39 (complementary to the mechanical interface 27), here designed as a plug by way of example. A light feedback channel is provided in this example, which is configured to receive light coupled in by the light coupling device 24 (see Figure in...). Fig. 6b), which has passed through the transparent glaze 16, from the second side edge 22 to the first side edge 20 (cf. light Sr in Fig.6b ), on which the light coupling device 24 and the light coupling device 26 are arranged.

[0123] In this example, the light return channel is arranged within the transparent glaze 16, with a mirror or reflector element 41 positioned at the second side edge 22. Light (ray path S) is generated by the light source 30 and coupled into the transparent glaze 16 at the first side edge 20. The light (cf. St in Fig. 6b ) reaches the second side edge 22, where it is reflected by means of a mirror element or reflection element 41. This allows the light to return from the second side edge 22 to the first side edge 20 within the transparent glaze 16 (cf. Sr in Fig. 6b ).

[0124] The example also includes a calibration channel Sc (see below). Fig. 6b), which optically couples the light coupling device 24 and the light coupling device 26 directly to each other, bypassing the transparent glaze 16. The calibration channel Sc, as well as the light source 30 and the photoreceptor 32, can be arranged in the connector counterpart 39. Calibration is possible via the calibration channel Sc, thus increasing the measurement accuracy.

[0125] As an alternative to a light return channel integrated in the transparent glaze 16, a light guiding channel arranged outside the transparent glaze 16 can be provided, e.g. in the form of an external light guide 37 (see Figure 37). Fig.6a ). In contrast to the design according to Figure 6b would a return of the light (cf. Sr in Figure 6b ) outside the transparent glaze 16 in the light guide 37.

[0126] Figure 7 shows one possible design of the protective plate 10, which largely corresponds to that associated with the Figure 1 , 3a and 3b The protective plate 10 described corresponds to this, so to avoid repetition, reference is first made to the explanations given there.

[0127] In contrast, in the present protective plate 10, the light coupling device 24 and the light coupling device 26 are combined into a single unit 43 for transmitting and receiving a pulsed light signal (transceiver). The unit 43 is arranged in a connector counterpart 39 (complementary to the mechanical interface 27), shown here as a plug. For clarity, the plug is shown disconnected from the mechanical interface 27.

[0128] Unit 43 is arranged on the first side edge 20. A mirror element or reflector element 41 is arranged on the second side edge 22. An example signal waveform of a pulsed light signal is illustrated in diagram 45.

[0129] The pulsed light signal is emitted by unit 43 at the first side edge 20 and enters the transparent glaze 16. The pulsed light signal passes through the transparent glaze 16 in the direction of the second side edge 22 (see St in Figure 7 At the second side edge 22, the pulsed light signal is reflected by means of a mirror element or reflector element 41. The reflected light signal passes through the transparent glaze 16 from the second side edge 22 towards the first side edge 20 (cf. Sr in Figure 7 ). The pulsed light signal is then detected at the first side edge 20 by unit 43 and can be evaluated accordingly.

Claims

1. Ballistic protective plate (10), with a protective layer (14) made of structural ceramic, characterized by the fact that A transparent glaze (16, 18) is applied to and bonded with the structural ceramic on a first side (15) and / or on a second side (17) of the structural ceramic facing away from the first side (15), wherein the transparent glaze (16, 18) covers at least the majority of the respective side (15, 17) of the structural ceramic, wherein a light coupling device (24) and a light coupling device (26) are provided, which are each optically coupled to the transparent glaze (16, 18) in such a way that light coupled into the transparent glaze (16, 18) at the light coupling device (24) can pass through the transparent glaze (16, 18) and strike the light coupling device (26).

2. Ballistic protective plate (10) according to claim 1, characterized by the fact thatthe light coupling device (24) and / or the light coupling device (26) each have a mechanical interface (27) and / or an optical element (28), in particular a lens, and / or the light coupling device (24) has a light source (30), in particular an LED, and / or the light coupling device (26) has a light receptor (32), in particular a photodiode.

3. Ballistic protective plate (10) according to claim 2, characterized by the fact that the light source (30) and / or the photoreceptor (32) can be coupled or are coupled to an electrical or electronic test device (80), wherein the test device (80) is configured to determine one or more light properties of the light incident on the photoreceptor (32) when the light source (30) is activated.

4. Ballistic protective plate (10) according to one of the preceding claims, characterized by the fact thatA reflective layer (38, 40) is applied to the transparent glaze (16, 18) on the side facing away from the structural ceramic and / or on the side facing the structural ceramic.

5. Ballistic protective plate (10) according to one of the preceding claims, characterized by the fact that on the first side a splinter protection layer (42) is applied to the transparent glaze (16, 18) on the side facing away from the structural ceramic and / or that on the second side a reinforcing layer (44) is applied to the transparent glaze (16, 18) on the side facing away from the structural ceramic, in particular made of fiber composite materials.

6. Ballistic protective plate (10) according to one of the preceding claims, characterized by the fact that the structural ceramic and the at least one transparent glaze (16, 18), preferably also the splinter protection layer (42) and / or the reinforcement layer (44), are enclosed by a cover layer (46).

7. Ballistic protective plate (10) according to claim 1 and 6, characterized by the fact that the light coupling device (24) and the light coupling device (26) or a connecting line (34) connected to the light coupling device (24) and the light coupling device (26) protrudes from the cover layer (46).

8. Ballistic protective plate (10) according to one of the preceding claims, characterized by the fact that a calibration channel (Sc) is provided which optically couples the light coupling device (24) and the light coupling device (26) directly to each other, in particular bypassing the transparent glaze (16, 18) and / or that the light coupling device (24) and the light coupling device (26) are each attached to a side edge (20, 22) of the transparent glaze (16, 18).

9. Ballistic protective plate (10) according to claim 8, characterized by the fact thatthe light coupling device (24) is attached to a first side edge (20) of the transparent glaze (16, 18) and the light coupling device (26) is attached to a second side edge (22) of the transparent glaze (16, 18), in particular to a side edge (22) opposite the first side edge (20).

10. Ballistic protective plate (10) according to claim 8, characterized by , that the light coupling device (24) and the light coupling device (26) are both arranged on the same side edge (20, 22) of the transparent glaze (16, 18).

11. Ballistic protective plate (10) according to claim 9 or 10, characterized by the fact thata light return channel is provided which is designed to return light coupled by the light coupling device (24), which has passed through the transparent glaze (16, 18), from the second side edge (22) to the side edge (20) on which the light coupling device (24) and the light coupling device (26) are arranged and / or that the light coupling device (24) and the light coupling device (26) are combined into a unit (43) for emitting and receiving a pulsed light signal.

12. Testing device (100) for crack testing of a ballistic protective plate (10) with a protective layer (14) made of structural ceramic, a transparent glaze (16, 18) applied to a first side (15) of the structural ceramic (14) and / or to a second side (17) of the structural ceramic with at least partially exposed side edges (20, 22), in particular a ballistic protective plate (10) according to one of claims 1 to 11, the testing device comprising: - an electrical energy source (104), - an electrical connection device (108) for connecting a light source (30) and a photoreceptor (32), - an evaluation device (110) powered by the energy source (104) and electrically and / or electronically coupled to the connection device (108) for determining one or more light properties detected by the photoreceptor (32).

13. Test device (100) according to claim 12, characterized by the fact thata light source (30) and a photoreceptor (32) are provided, which are electrically connected to a connecting cable (34) for connection to the connection device (108) and / or that a further light source and a further photoreceptor are provided, which are connected to the connecting cable (34) for connection to the connection device (108).

14. Test device (100) according to one of claims 12 to 13, characterized by the fact that an output device (112) is provided which interacts with the evaluation device (110) and is configured to output an optical and / or acoustic signal when the light source (30) is active and one of the light properties of the light incident on the photoreceptor (32) falls below or exceeds a threshold value.

15. Test device (100) according to one of claims 12 to 14, characterized by the fact thatthe output device (112) for optical signal output has a display (114), a display or at least an LED (115, 116) and / or the output device (112) for acoustic signal output has a loudspeaker and / or a wireless or wired interface (118) coupled to the evaluation device (110) is provided for transmitting signals from the evaluation device (110).

16. Set (200) comprising a ballistic protective plate (10) according to any one of claims 1 to 11 and a test device (100) according to any one of claims 12 to 15.

17. Method for crack testing of a ballistic protective plate (10) with a protective layer (14) made of structural ceramic, a transparent glaze (16, 18) applied to a first side (15) of the structural ceramic and / or to a second side (17) of the structural ceramic with at least partially exposed side edges (20, 22), in particular a ballistic protective plate (10) according to any one of claims 1 to 11, the method comprising the following steps: - illuminating a side edge (20) of the transparent glaze (16, 18) so that light incident on this side edge (20) can pass through the transparent glaze (16, 18) and exit the transparent glaze (16, 18) at the same side edge (20) or at an opposite side edge (22), - detecting the light exiting at the same side edge (20) or at the opposite side edge (22), and - determining,whether one or more light properties of the emitted light fall below or exceed a threshold value.

18. Method according to claim 17, characterized by The steps are: - Illuminating a third, at least partially exposed, side edge of the transparent glaze (16, 18) so that light incident on this side edge can pass through the transparent glaze (16, 18) and exit the transparent glaze at the third side edge or at a fourth side edge opposite the third side edge (also at least partially exposed), - Detecting the light exiting at the third side edge or at the fourth side edge, and - Determining whether one or more light properties of the exiting light fall below or exceed a threshold value.

19. Method according to claim 17 or 18, characterized by the fact thatat least when a signal is output if one of the light properties of the emitted light falls below or exceeds a threshold value and / or the signal is transmitted to an external receiver (150).

Images