DE102011003073A1 - Glazing arrangement with safety function, safety system for a glazing arrangement and method for detecting a mechanical or thermal stress of a planar glazing element - Google Patents

Abstract

A glazing arrangement 10 with a safety function comprises a flat glazing element 20 and an optical waveguide structure 30 with an optical filter element 32, the optical waveguide structure 30 being mechanically arranged on the glazing element 20 in order to change an optical property of the optical waveguide structure when the flat glazing element 20 is subjected to mechanical or thermal stress 30 effect.

Description

The present invention relates to a glazing assembly with safety function, to a security system for a glazing assembly and to a method for detecting a mechanical or thermal stress of a planar glazing member. In particular, the present invention relates to a concept for monitoring a planar glazing element, for. As a glass or a laminated glass to capture a mechanical or thermal stress by an external action on the sheet-like glazing element early or timely. As a result, an attempted manipulation of the planar glazing element, for example during a break-in attempt, can be detected almost in real time and a corresponding alarm can be triggered at an early stage. Similarly, the inventive concept can be used on flat glazing elements that are exposed in their use strong mechanical and / or thermal loads, such. As on windscreens in an aircraft cockpit, in trains or other vehicles to early detect too high mechanical or thermal loads on the glazing elements and to avoid mechanical failure due to a sudden, unforeseen breakage of the planar glazing element.

In many fields so-called safety glass is used to either glaze, z. As bulletproof glass or laminated safety glass to provide as much as possible burglar-resistant effect or unauthorized physical access to areas that are secured by safety glass, z. As expenses of jewelers, showcases, etc., as safe as possible to prevent. In addition, so-called passive glass breakage detectors are used for the respective glazing elements, which are arranged on the glazing to be monitored, and detect a broken glass or a physical destruction of the glazing element. In this context, different DIN standards refer to so-called resistance classes ( DIN V ENV 1627 ), which take into account, for example, resistance times, ie the time that a product can withstand burglary, the types of perpetrators and the modus operandi. Furthermore, there are test standards ( DIN EN 356 ) for antiperspirant glazings, ie to what extent the glazings are burglary-resistant, puncture-resistant or attack-inhibiting.

Furthermore, safety glass is also used in areas such. As windscreens in aircraft cockpits, high-speed trains or other vehicles that are exposed to very strong thermal and mechanical stresses in particular.

A disadvantage of the methods known hitherto in the prior art is that, for example, a break-in attempt is detected only when mechanical damage or destruction of the monitored glazing element occurs. If, for example, in a break-in attempt, the safety glass is changed in stability until the safety glass finally melts, a possible burglar can reach the valuables issued behind the safety glazing relatively quickly, without issuing an alarm from a passive glass breakage detector becomes. Furthermore, so far had to be used to identify a heat source in the security area consuming thermal imaging cameras, a timely heat information should be obtained. In order to obtain the most comprehensive detection of burglary, different monitoring concepts therefore had to be combined according to the prior art in order to detect both mechanical and thermal effects on safety glazings. This leads to their realization to a high cost and thus also high costs.

Based on this prior art, the object of the present invention is to provide a concept for a glazing arrangement with a safety function, by means of which a detection of acting on a planar glazing element mechanical and / or thermal stress or load detected early and possibly in real time can be.

This object is achieved by a glazing arrangement with safety function according to claim 1, by a safety glazing system according to claim 9, by a method for detecting a mechanical or thermal stress of a planar glazing element according to claim 15 and by a computer program according to claim 18.

The core idea of the present invention is to provide an optical waveguide structure with an optical filter element, such. As a fiber Bragg grating or Bragg filter, mechanically to be arranged on the planar glazing element, that at a mechanical or thermal stress of the glazing element, an optical property of the optical waveguide structure and in particular of the optical filter element is changed. A mechanical connection between a glazing element and an optical waveguide structure can be designed, for example, in a positive, non-positive or cohesive manner. Thus, in particular, according to the invention, use is made of the fact that in the case of an optical waveguide structure arranged Bragg filter due to mechanical or thermal stress of the planar glazing element to a strain influence and / or a change in refractive index of the material of the Bragg filter comes, so that the center frequency of the Bragg filter as a variable optical property of the optical waveguide structure according to changes mechanical or thermal action. Such a change in the center frequency of the Bragg filter is now relatively easily detectable with coupled to the optical waveguide structure optical detection elements, wherein the size of the change in the center frequency .DELTA.λ / λ _0, the degree of mechanical and / or thermal stress of the planar glazing element can be assigned. According to the invention can thus by evaluating the optical property of the Bragg filter in the optical waveguide structure directly on a manipulation, for. B. closed by a burglar, the flat glazing element. Furthermore, to increase the detection security "normal" thermal or mechanical effects, such. B. temperature changes due to solar radiation, are taken into account on the planar glazing element in the evaluation of the optical property of the optical waveguide structure.

Thus, according to the invention, an optical waveguide structure with an optical filter element or a plurality of optical filter elements, which are formed, for example, as Bragg filters, can be mechanically attached to a planar glazing element to be monitored. When using a plurality of Bragg filters, for example, these can have different filter center frequencies or filter center wavelengths in order to further obtain a spatial resolution of the mechanical or thermal stresses acting on the planar glazing element to be monitored, as will be explained in detail below.

The optical waveguide structure with the optical filter element or the optical filter elements can now, for example, on a multilayer, planar glazing element, for. B. a laminated glass arrangement are arranged, wherein the optical waveguide structure in a glass capillary, a milled groove or subsequently mounted on the safety glass in capillaries and is at least partially positively, positively and / or materially connected to the monitored, planar glazing element.

With regard to the mechanical connection of the glazing element to the optical waveguide structure, it should be pointed out that the optical waveguide structure either mechanically or in the same manner during the production of the glazing element in or on the same. H. can be arranged in a positive, force and / or material fit, or can also be subsequently arranged on the glazing element in subsequently mounted recesses or recesses (eg capillary or groove). If, for example, the optical waveguide structure with the optical filter elements is already integrated in the material of the glazing element during the production of the glazing element or fixed within one of several layers of a laminated glass arrangement, for example using a transparent adhesive, the optical waveguide structure can readily form, force and / or materially bond be arranged on the glazing element, so that a mechanical stress or strain (eg elongation) of the glass material is transmitted directly to the optical waveguide structure and the optical filter elements located therein. Likewise, thermal stress on the glazing element, i. H. a temperature increase, transmitted directly to the optical waveguide structure and the optical filter elements located therein.

In a subsequent arrangement of the optical waveguide structure on the glazing element, it must now be distinguished whether the optical waveguide structure can be inserted into an outwardly accessible recess (eg a milled groove) and connected substantially completely with an adhesive to the glazing element, or if Fiber optic structure when inserted into a designated glass capillary in the glazing element substantially only at the end points (ie at the entry and exit point of the optical waveguide structure on the glazing element) can be mechanically connected to the same. In the second case, a mechanical stress, z. As in the form of an elongation of the glazing element, as a relatively uniform elongation of the optical waveguide structure between the two fixed end points. Thus, in comparison with a complete mechanical connection of the optical waveguide structure with the glazing element, the detection of an elongation of the optical waveguide structure and thus of the glazing element continues to be possible, but without an exact spatial allocation of the location of the acting mechanical stress.

In contrast to mechanical stress, in the case of a selective connection of the optical waveguide structure to the glazing element, a spatial allocation of the location of the acting thermal stress is nevertheless possible with thermal treatment of the glazing element, since only corresponding sections of the optical waveguide structure and thus just heat certain Bragg filter elements and change their optical filter property.

By monitoring the optical property of the formed as a Bragg filter optical filter elements can now externally supplied heat or high pressure, as may be the case, for example, a burglary attempt on the resulting mechanical strain (or compression) of the monitored, planar glazing element and so that the mechanically connected optical waveguide structure can be detected very quickly and almost in real time and an electronic alarm triggered to indicate the manipulation of the to be monitored, planar glazing element. In addition, the optical waveguide structure arranged on the planar glazing element to be monitored can be used simultaneously with the optically series-connected Bragg filters as a rupture sensor, since only signals from those filter elements (having a sufficient amplitude) that are reflected in the optical waveguide structure are reflected back Positions (in Lichteinkoppelrichtung) are located in front of the break, while reflection signals from one or more Bragg filters fail behind the break.

The procedure according to the invention for implementing the glazing arrangement with a safety function can now be used extremely advantageously for monitoring a planar glazing element, since the optical waveguide structure with the optical filter elements designed as Bragg filters can be used to feed an optical signal into the optical waveguide structure, and by the evaluation of The optical filter elements reflected or transmitted optical signal can be determined directly and almost in real time information about a mechanical and / or thermal stress of the monitored, planar glazing element.

Thus, according to the invention, compared with the other methods known in the prior art with only one sensor arrangement, it is possible to detect both a heat action and an elongation or breakage (or kink) of the planar glazing element to be monitored, whereby the respective state of the component to be monitored, planar information glazing element descriptive information in the form of a change in the optical property of the optical waveguide structure directly and almost in real time are readable. The glazing assembly according to the invention with security function is thus used everywhere where valuables, goods or other items to be secured against unauthorized access or access, z. As in jewelers, banks, department stores, etc. In addition, mechanical stresses in heavily used discs, such. B. of windscreens in aircraft cockpits, trains or other vehicles, are detected in good time.

Preferred embodiments of the present invention will be explained below with reference to the accompanying drawings. Show it:

1a -B are schematic representations in a plan view and a sectional view of a safety glazing assembly according to the invention according to an embodiment of the present invention;

2a C shows a basic illustration of an optical waveguide structure with an optical filter element for the safety-type glazing arrangement according to the invention, according to an embodiment of the present invention;

3 a schematic diagram of a glazing assembly with security function according to another embodiment of the present invention;

4 a schematic diagram of a security system for a glazing assembly according to another embodiment of the present invention; and

5 a schematic flow diagram of a method according to another embodiment of the present invention.

Before the present invention is explained in more detail below with reference to the drawings, it is pointed out that identical, functionally identical or equivalent elements in the different figures are provided with the same reference numerals, so that the description of the elements shown in the different embodiments with the same reference numerals interchangeable with each other or can be applied to each other.

The following will now be based on 1a -B the basic structure and the basic operation of a glazing assembly according to the invention 10 with safety function according to a first embodiment of the present invention with reference to the in 2a C illustrated basic configuration of an optical waveguide structure 30 with an optical filter element 32 described by way of example.

As in 1a is shown, the glazing assembly 10 a flat glazing element 20 on. The planar glazing element can, for example, be a single-layer or multi-layered one transparent material, eg. As glass, plastic or a composite material, have. For example, the flat glazing element 20 for a safety glazing as a laminated glass a combination of glass and transparent plastic films have. On the flat glazing element 20 is now an optical waveguide structure 30 with an optical filter element, e.g. B. in the form of a fiber Bragg grating or an optical Bragg filter arranged. The optical waveguide structure 30 thus has an optical waveguide section 34 and the optical filter element 32 on. Furthermore, the optical waveguide structure 30 a Einkoppeleingang 36 for coupling an optical signal S ₁ into the optical waveguide structure 30 on. Furthermore, the optical waveguide structure 30 also after the optical filter element 32 optionally a further optical waveguide section 34 on, wherein the further optical waveguide section 34 for example, to a Auskoppelausgang 38 on any side surface, z. B. an opposite side surface of the flat glazing element 20 for decoupling one through the optical filter element 32 passing optical signal S _Tr is performed.

Like now in 1a -B is the optical waveguide structure 30 within the material of the planar glazing element 20 arranged. As in 1b shown, the flat glazing element 20 For example, as a laminated glass a plurality of individual layers 20-1 , ..., 20-5 ( 20-n ) wherein the optical waveguide structure 30 for example, in a small capillary or a milled groove in the second glazing layer 20-2 (behind the first disc 20-1 ) of the planar glazing element 20 is arranged.

This in 1a -B illustrated arrangement of the optical waveguide structure 30 on the flat glazing element 20 but is to be regarded as exemplary only. So can the optical waveguide structure 30 generally in a recess or recess 40 within the material of the planar glazing element 20 or on a surface of the planar glazing element 20 be introduced. Of course, in the manufacture of the flat glazing element 20 corresponding recesses or recesses on or in the glazing element 20 be provided in advance for insertion or insertion of the optical waveguide structure. The optical waveguide structure 30 can now, for example, by means of a transparent adhesive material or other fastening material in the recess provided 40 be attached.

Furthermore, it is also possible, the optical waveguide structure 30 still later on a glazing element 20 to arrange. In a subsequent installation in a z. B. subsequently provided recess or recess 40 (or depression) on the glazing element 20 can the optical waveguide structure 30 for example by means of a foil (not shown in FIG 1a B) fixed on the surface of the planar glazing element 20 at least in the area of the recesses 40 for the optical waveguide structure 30 on the surface of the planar glazing element 20 is glued.

Regarding a local resolution of a mechanical stress of the glazing element 20 It should be noted that this mechanical stress when using a plurality of Bragg filter elements 32 only on the areas of the glazing element 20 can be detected spatially resolved, in which a fixed or non-positive mechanical connection of the optical waveguide structure 30 with the optical filter elements 32 is present on the glazing element. In this regard, the detailed remarks in 4 which are applicable to all embodiments of the present invention.

In connection with in 1a -B illustrated optical waveguide structure 30 It should be noted that these are merely an optical filter element to simplify the description 32 having. In the following description, it will become clear that a plurality of optical filter elements in the optical waveguide structure 30 can be arranged, wherein the optical waveguide structure 30 also along substantially arbitrarily shaped, z. B. meander-shaped, recesses 40 in the planar glazing element 20 can be arranged. Furthermore, further optical waveguide structures (not shown in FIG 1a B) with respective coupling inputs and optional coupling inputs in the planar glazing element 20 be arranged separately from each other.

The optical waveguide structure (s) 30 each having a plurality of optical filter elements 32 can now so on the flat glazing element 20 be arranged, for example, a distributed in a grid arrangement of sensor elements (in the form of the optical filter elements 32 ) distributed over the base of the flat glazing element 20 to obtain. In such an arrangement of the optical waveguide structure 30 on the flat glazing element 20 will be detailed in the following by means of 3 received.

It should also be noted that the rectangular and straight shape of the surface of the planar glazing element 20 , as shown in the figures, is to be regarded as exemplary only. The concept of the invention is in particular also arbitrarily shaped and also curved surfaces of a flat glazing element 20 applicable.

As in 1b now shown, the optical waveguide structure 30 with the optical filter element 32 For example, a diameter "a" of 80-200 .mu.m, so that, for example, in the flat glazing element 20 provided recess 40 Dimensions with a width "b" and a height "c" of, for example, 200-650 microns may have to the optical waveguide structure 30 take. In a possible gap between the optical waveguide structure 30 and the side walls of the recess 40 For example, a transparent adhesive or other transparent bonding material (not shown in U.S. Pat 1a B) be provided for filling any cavities, for maintaining the mechanical stability and for fixing to the glass (adhesion), as far as the adhesive can be introduced into the recesses.

The optical waveguide structure 30 with the optical filter element 32 is now so on the flat glazing element 20 arranged that any mechanical and / or thermal stresses on the flat glazing element 20 act as directly as possible on the optical waveguide structure 30 with the optical filter element 32 be transferred or at least passed on to a certain extent. That is, the optical waveguide structure 30 is so mechanically on the flat glazing element 20 arranged that a mechanical or thermal stress, ie the action of an elevated temperature or an external mechanical force on the planar glazing element 20 , a change in the optical property of the optical waveguide structure 30 and in particular the optical filter element 32 the optical waveguide structure 30 causes. For this it is necessary that the optical waveguide structure 30 sufficiently thermally and / or mechanically with the planar glazing element 20 is coupled to a sufficient heat and / or power transmission from the sheet-like glazing element 20 on the optical waveguide structure 30 to ensure. By mechanical forces are meant, for example, tensile, compressive, impact, shock or bending loads. To a thermal coupling of the optical waveguide structure 30 with the flat glazing element 20 to provide, it is only to be noted that the flat glazing element 20 and the optical waveguide structure 30 are arranged sufficiently close to each other or in (thermal) contact with each other. To further mechanical loads of the planar glazing element 20 to a sufficient degree to the optical waveguide structure 30 to transmit or forward, a corresponding mechanical connection, for. B. a force, positive and / or cohesive connection, the optical waveguide structure 30 with the optical filter element 32 on the flat glazing element 20 be provided.

In the following, reference will now be made, in particular 2a C, how the relationship between a mechanical and / or thermal stress of the planar glazing element 20 and a change of an optical property of the optical waveguide structure 30 and in particular the optical filter element 32 the optical waveguide structure 30 , which is present for example in the form of a Bragg filter is obtained.

As in 2a C is the optical filter element 32 For example, formed as a fiber Bragg grating or optical Bragg filter. The Bragg filter 32 is one in the glass fiber core of the optical waveguide structure 30 inscribed optical interference filter. Wavelength of the in the optical waveguide structure 30 coupled optical signal S ₁ (with the power distribution P ₁ ), which are within the filter bandwidth around the center bandwidth λ _{B of} the Bragg filter are (at least largely) reflected back and give the reflected signal S _R1 with the power distribution P _R1 .

The optical waveguide structure 30 in the form of a single-mode glass fiber thus has a highly transparent glass fiber core 30-1 with refractive index n ₂ , that with a glass material 30-2 lower refractive index n _{1 is} sheathed. The optical waveguide thus consists of a core 30-1 with the refractive index n ₂ , a cladding (cladding) 30-2 with the refractive index n ₁ and, for example, a protective coating (coating / buffer) 30-3 with a refractive index n ₀ . The light-guiding core 30-1 serves for guiding and transmitting the optical signal S ₁ . The coat 30-2 has a lower optical refractive index than the core 30-1 , ie n ₁ <n ₂ . The coat 30-2 thereby causes a total reflection at the boundary layer to the core 30-1 and thus guiding the radiation (ie the optical signal) in the core 30-1 of the optical fiber 30 , The optical filter element 32 along the core 30-1 the optical waveguide structure 34 is in the fiber core 30-1 arranged in the form of a periodic modulation of the refractive index, with high (n ₃ ) and low refractive index ranges (n ₂ ) representing the light in the fiber core 30-1 reflect back to a certain wavelength λ _B , and thus have the function of a band-stop filter, with n ₃ >> n ₂ . The center wavelength λ _{B of} the filter bandwidth is given by the Bragg condition λ _B = 2neff · Λ. (1)

Where _{neff is} the effective refractive index of the fiber core 30-1 the optical waveguide structure 30 and Λ the grating period. The spectral width of the band (blocking band) depends on the length of the fiber Bragg grating 32 and the strength of the refractive index change between the adjacent refractive index regions.

2 B now shows by way of example the reflection behavior of the optical waveguide structure 30 with the Bragg filter 32 , The spectrum of the input power P _{I of} the optical input signal S ₁ over the wavelength λ. The Bragg filter 32 acts as a bandpass filter, so that a portion of the injected spectrum is reflected back as a reflected portion P _R1 , ie the Bragg filter 32 acts as a band-stop filter the center wavelength λ _B. In addition, in 2 B exemplified the transmission spectrum of the transmitted or continuous power P _{Tr, wherein} the proportion around the center frequency λ _B through the Bragg filter 32 was removed from the transmission spectrum.

Regarding the in 2 B shown power spectra is noted that they are to be regarded as exemplary only. In particular, it should be noted that the band-stop filter functionality realized by a Bragg filter allows very narrow blocking or reflection ranges around the center wavelength λ ₃ , while in 2 B this blocking area is shown relatively wide for the sake of simplicity of illustration.

As apparent from the above equation (1), the center wavelength λ _{B of} the Bragg filter depends 32 each of the effective refractive index and the grating period Λ of the formed as a fiber Bragg grating optical filter element 32 from. In this context, it is now pointed out that the grating period Λ by an applied mechanical load, ie a strain or compression due to a tensile, compressive, impact, shock or bending load changes. So if the optical waveguide structure 30 with the optical filter element 32 mechanically with the flat glazing element 20 is coupled, so that strain or compression deformation due to mechanical or thermal stresses of the planar glazing element 20 also on the Bragg filter 32 the optical waveguide structure 30 at least partially transmitted, the grating period Λ of the Bragg filter changes 32 and thus also the center wavelength λ _{B of} the Bragg filter 32 , In addition, the refractive indices n ₂ , n ₃ in the fiber core 30-1 Also dependent on temperature, so that in addition the center wavelength λ _{B changes} according to the thermal load on the flat glazing element 20 and thus also on the optical filter element 32 the optical waveguide structure 30 acts.

It follows that the wavelength change Δλ _{B has} a dependence on the acting mechanical and thermal load: Δλ _B = f (F; T) (2)

As a result, the invention achieves that a mechanical or thermal stress of the flat filter element 20 For example, in a burglary attempt or heavy use during use z. As a windshield of a vehicle, a change in the optical property of the optical waveguide structure 30 and in particular the optical Bragg filter integrated therein 32 is caused.

2c shows by way of example resulting power spectra of an optical waveguide structure 30 comprising two optical filter elements (not shown in FIG 1a or 2a ) having. In this case, the two Bragg filters are each designed so that they have different center wavelengths λ _B1 , λ _B2 , so that, knowing the position of the first and second optical filter element with a change in the center wavelength λ _B1 , λ _{B2 in} addition to the size of the mechanical or thermal stress can also be closed to a position at which the mechanical or thermal stress of the planar glazing element 20 he follows. Since Bragg filters can now be formed as extremely narrow bandstop filters with a fixed center wavelength λ _Bn , a larger number of Bragg filters can also be formed 32-n in the optical waveguide structure 30 be realized so that spatially resolved monitoring of the planar glazing element 20 with regard to mechanical and / or thermal external stresses can be realized.

However, all implementations have the same basic principle as that, due to the change in the center wavelength Δλ _{Bn of} the Bragg filter, the magnitude of the externally applied mechanical or thermal stress can be assigned, so that when a limit value is exceeded at least one of the optical filter elements 32 a critical (anomalous) condition, e.g. B. a burglary attempt on the flat glazing element 20 can be determined. In addition, simultaneously with the in a flat glazing element 20 integrated optical waveguide structure 30 be detected when a breakage of the glazing element 20 and thus the break or kink of the optical waveguide structure 30 occurs because then of an optical filter element 32 that in the optical waveguide structure 30 is arranged in Lichteinkoppelrichtung after the fracture, no or a greatly reduced reflection signal returns and thus safe to mechanical damage in the form of a fracture of the glazing element 20 can be closed.

3 shows a possible embodiment of the invention glazing assembly 10 , In the flat glazing element 20 is an optical waveguide structure 30 with a plurality of optical filter elements 32-n arranged. The optical waveguide structure 30 is now trained again to be at a Einkoppelanschluss 36 the optical signal S ₁ in the optical waveguide structure 30 couple, wherein, for example, on the first Bragg filter element 32-1 a first portion of the optical signal at the first center wavelength λ _B1 as the first reflection signal S _R1 , at the second Bragg filter 32-2 at a second center wavelength λ _B2, a second reflection signal S _R2 , etc., up to the last Bragg filter element 32-n at a center wavelength λBn, the reflection signal S _Rn to the coupling terminal 36 is reflected back. Furthermore, it is also possible to use an optionally provided decoupling connection 38 the transmission spectrum P _Tr in the form of crossing signal S _Tr changes with respect to one or more of center wavelengths of one or more of the Bragg filter 32 to investigate.

As in 3 is the optical waveguide structure 30 with the optical filter elements 32-n meandering on the flat glazing element 20 and, for example, within a specially provided recess (not shown in FIG 3 ) mechanically, z. B. positive, non-positive or cohesive, on the flat glazing element 20 attached. Thus, arranged as sensor elements Bragg filter 32-n distributed in a grid on the flat glazing element 20 arranged. The distances A, B or C between adjacent Bragg filters 32-n be chosen so that, depending on the thermal conductivity or the thermal conductivity of the planar glazing element 20 ie the individual Bragg filters 32-n surrounding material, with a punctual heating of the disc to z. B. 500 ° C (or more) at the nearest Bragg filter within a period of z. B. ≤ 5 seconds a clearly above the normal temperature fluctuations detected temperature increase, z. B. greater than 10 ° C, is caused. Its center wavelength would typically increase by at least about 100 pm.

For example, the optical waveguide structure 30 with the optical filter elements 32-n so on the flat glazing element 20 be arranged such that per unit area (eg 0.01-1.0 m ² ) at least one Bragg filter 32 is arranged to safely detect a thermal or mechanical stress via a change in the optical properties of the optical waveguide structure (s).

As in 3 are the plurality of optical filter elements 32-n along an optical waveguide structure 30 arranged. According to the invention it is equally possible, even several optical waveguide structures 30-1 , ..., 30-n each with one or more optical filter elements, for. B. in the form of a Bragg filter, in the planar glazing element 20 to provide a plurality of optically separate sensor circuits on the planar glazing element 20 to install. This can be done with a very large glazing element 20 be beneficial.

In the 3 illustrated optical waveguide structure 30 can on the flat glazing element 20 also within a depression or recess in the planar glazing element 20 For example, by means of a compound-producing adhesive (not shown in FIG 3 ) mechanically so on the flat glazing element 20 be arranged to provide sufficient mechanical and thermal coupling between the glazing element 20 and the optical waveguide structure 30 as already stated by 1a -B has been explained, with the comments made there as well in the 3 shown arrangement is applicable.

In the 3 illustrated glazing arrangement 10 with safety function is now on the one hand suitable for mechanical deformation due to a thermal or mechanical action on the flat glazing element 20 capture. In addition, with the in 3a also shown a rupture of the planar glazing element 20 and thus due to a corresponding break or bend also the optical waveguide structure 30 be recorded. In 3 is an example of a break point 60 within or on the planar glazing element 20 shown. That at the connection 36 received reflected signal S _Rn now contains no or greatly reduced reflection signals of in 3 illustrated Bragg filter 32-9 . 32-10 ... 32-n in the light coupling device after the breaking point 60 are arranged. This can be a mechanical breaking of the glazing element 20 and thus breaking or buckling of the optical waveguide structure 30 detected and a position between the two Bragg filter elements 32-8 and 32-9 be assigned. Thus, with the reflection signal S _R also depends on the respective spacing of the Bragg filter elements 32-n a local resolution of a thermal or mechanical stress of the planar glazing element 20 via a change in individual center wavelengths λ _Bn , or a localization of a fraction of the planar glazing element, possible by detecting a failure of the reflection signals or a sharp decrease (> 50%) of the amplitude of the reflection signal S _{Rn of} the Bragg filter elements after a break.

Regarding a local resolution or spatial assignment of a mechanical Stress of the glazing element 20 It is pointed out that this mechanical stress can be detected in a spatially resolved manner only with the use of a plurality of Bragg filter elements only at the regions of the glazing element where there is a fixed mechanical connection of the optical waveguide structure 30 with the optical filter elements 32 is present on the glazing element.

For example, is the optical waveguide structure 30 over the entire length mechanically with the glazing element 20 connected over the entire length of the optical waveguide structure 30 , are arranged on the Bragg filter elements, a local resolution of one on the glazing element 20 acting mechanical stress. The local resolution corresponds to the spacing of the filter elements. But now, for example, the optical waveguide structure 30 subsequently in one of the glazing element 20 provided capillary 40 introduced, it is often only possible at the respective end pieces of the optical waveguide structure 30 coming from the glazing element 20 protrude, a mechanical fixation between the optical waveguide structure 30 and the glazing element 20 make. At a mechanical stress of the glazing element 20 is then only one over the entire in the glazing element 20 arranged optical waveguide structure 30 relatively uniformly induced strain detectable, so that it is only recognized that somewhere along this capillary (and not in adjacent) a mechanical stress was carried out.

With regard to the above discussion of possible alternatives for a mechanical arrangement of the optical waveguide structure 30 on the glazing element 20 It should become clear that with only a certain area-wise fixed mechanical connection of the optical waveguide structure 30 on the glazing element 20 within the fixed mechanical connection areas directly a mechanical stress on the glazing element also on the optical waveguide structure 30 is transferred to a possible intermediate area without such a fixed mechanical connection, a mechanical stress of the glazing element 20 is transmitted as a relatively uniform strain between the mechanical connection points, a precise spatial resolution is therefore not possible.

In this context, it should be noted that a local resolution at a thermal stress of the glazing element 20 i. W. regardless of the mechanical connection between the optical waveguide structure 30 and the glazing element 20 is, as long as a sufficiently good thermal coupling of the optical waveguide structure 30 with the glazing element 20 over the entire length of the optical waveguide structure 30 is present, which is already given by resting.

The following will now be based on 4 an embodiment of a security system 70 for glazing example described.

As in 4 shown, instructs the security system 70 For example, a glazing arrangement 10 on, as based on the previous one 1a -b, 2a -C and 3 have been described and can be used in the embodiment shown below.

As in 4 further illustrated is at the docking port 36 a signal input device 80 for coupling an optical signal S ₁ into the optical waveguide structure 30 intended. Furthermore, a signal detection device 82 for detecting an optical signal (ie the reflection signal S _R and / or optionally the transmission signal S _Tr ) of the optical waveguide structure 30 and for outputting an electrical detection signal S _e based on the detected optical signal S _R and S _Tr , respectively. The signal input device 80 is thus formed as an optical transmitter, while the signal detection device 82 is designed as an optical receiver. The signal detection device 82 is designed such that, for example, that at the coupling connection 36 provided reflection signal S _R and optionally that on the optional Ankoppelanschluss 38 provided optional transmission signal S _T or the respective power spectrum can capture. In the signal detection device, the detected optical signals are converted, for example, into electrical signals S _e for further processing and / or evaluation by a processing device 90 transformed. The processing device 90 is provided on the one hand, for example, the signal input device 80 to drive the coupling of the optical signal S ₁ and further to that of the signal detection means 82 provided detection signal S _e based on the reflection signal S _R or the transmission signal S _Tr evaluate. In this case, the processing device 90 in particular designed to change the property of the optical waveguide structure 30 at a mechanical or thermal stress of the glazing element 20 to investigate. The processing device and optionally also the signal input and signal detection device 80 . 82 can be adjacent to the glazing assembly 10 or via an optical fiber connection (not shown in FIG 4 ) away from the glazing assembly 10 be arranged, for example, no unauthorized access and no manipulation attempt, eg. B. in a burglary, on the security system 70 to enable.

As already mentioned above, the processing device 90 based on that of the respective Bragg filters 32-n reflected signal S _R or on the transmission signal S _Tr a mechanical or thermal stress of the planar glazing element 20 and thus the mechanically coupled optical waveguide structure 30 with the Bragg filter element 32 or the plurality of Bragg filter elements 32-n determine. Thus, the processing device 90 a change in the center wavelength λ _{Bn of} at least one of the Bragg filter elements 32-n and detect when it exceeds a comparison value for a wavelength change, a corresponding display signal or alarm signal S _OUT at an output terminal 92 output.

Furthermore, the processing device 90 at the output terminal 92 a corresponding alarm output signal S _OUT output when in the reflection signal S _{R is} not the reflection spectra of all Bragg filter elements 32-n are included, as this is due to a fracture of the planar glazing element 20 and thus a break or kink of the optical waveguide structure 30 points.

The processing device 90 is configured to compare the detection signal S _e or a signal derived therefrom with a comparison value to determine whether the detection signal is within or outside a desired range, and to exceed the limit value for a mechanical or thermal stress of the planar glazing element 20 to point.

The comparison value may be determined, for example, based on an average or a plurality of preceding measurement values of the detection signal or signals derived therefrom. It can thus be achieved that, for example, a relatively slow thermal temperature change on the planar glazing element, as occurs, for example, due to solar radiation, does not lead to the triggering of an alarm, while, for example, a heat effect of high power, as is caused, for example, by a gas burner of a burglar, extremely fast or immediately leads to an alarm signal. Today's gas burners have a heat radiation of more than 1900 ° C and a power of over 50 kW.

In addition to a relative comparison value, which is readjusted based on an average value or a quantity derived therefrom of a plurality of preceding measured values of the detection signal, a second fixed comparison value can be provided, beyond which an alarm is triggered in any case, since this is in any case attributable to an high thermal or mechanical stress of the planar glazing element 20 indicates, even if it has risen only slowly.

As described above, the detection signal or the signal derived therefrom is based on a center frequency of the respective Bragg filter or a level of the detected signal. The processing device 90 is thus designed to detect the spectral distribution of the signal components in the reflection signal S _R and also the respective level and to investigate a change in the respective signal components attributable to a mechanical or thermal stress.

At the in 4 illustrated security system 70 for a glazing are the signal input device 80 , the signal detection device 82 and the processing device 90 represented in the schematic diagram as separate elements or components, these elements or components but also to a single assembly 100 can be summarized.

The assembly 100 is also referred to as an optical sensor interrogator or fiber Bragg grating optical interrogator. In addition, it should be noted that available fiber bragg grating interrogators can, for example, monitor up to 100 Bragg filter elements in series, so that with a single interrogator, relatively high spatial resolution can be achieved by monitoring a large number of Bragg filter elements in the array optical waveguide structure 30 can be achieved. Furthermore, the number of measuring points can be determined by the use of an optical switch (not shown in FIG 4 ).

In principle, extremely small strains or compressions can be detected by a Bragg grating, as they are already caused by slight contact with the disk or, in the case of larger disks, by the wind pressure. Furthermore, comparable shifts in the center wavelength of a Bragg grating but also caused by temperature fluctuations by a few ° C. The safety system according to the invention 70 can now be adapted to, depending on the specific application, eg. For example, depending on the pane construction, set from which wavelength shift an alarm is triggered. A distinction between punctual thermal and mechanical loads, for example, possible in that when bending a disc several adjacent Bragg grating respond simultaneously, while the heat propagation is relatively slow, so that adjacent Bragg grating only at a distance of a few seconds to minutes respond, depending after distance and disc structure.

Moreover, it is pointed out that, for example, in the case of a laminated glass arrangement for the glazing element within the composite arrangement, a heat-conducting film, ie a film with an elevated heat-conducting property relative to the surrounding glass material, can be used in order to minimize the thermal stress acting on a punctual, thermal heat source quickly distributed over the glazing element to near sufficient heating in near real time of the glass material in the vicinity of a Bragg filter element in the optical waveguide structure 30 to detect directly (within a few seconds) a heat effect indicative of tampering.

The following will now be based on 5 an embodiment of a basic method 100 for detecting a mechanical or thermal stress of a planar glazing element, wherein an optical waveguide structure with an optical filter element is arranged on the planar glazing element. In the process 100 is first at a first step 102 an optical signal coupled into the optical waveguide structure. Further, an optical signal, for. In the form of a reflection signal or a transmission signal, the optical waveguide structure is detected and converted into an electrical detection signal based on the detected optical signal of the optical waveguide structure (step 104 ). This electrical detection signal or a signal derived therefrom is now evaluated (step 106 ) to detect a change in optical property of the optical waveguide structure due to mechanical or thermal stress of the planar glazing element.

As an optional step 108 For example, the electrical detection signal or the signal derived therefrom may be compared with a comparison value to determine whether the detection signal is outside a desired range, this indicating an exceeding of a limit value for a mechanical or thermal stress on the planar glazing element. In this case, the comparison value can be predefined or can be determined as a relative comparison value based on a statistical processing of a plurality of preceding measurement values of the electrical detection signal.

Aspects of the inventive concept for a glazing arrangement with a safety function or a security system for a glazing arrangement will be summarized below.

In a burglary attempt, for example, the safety glass of a jeweler's display or other display protecting disc by means of a gas burner under heat or heat to be changed in stability so as to melt the safety glass at least partially so that access to the behind the safety glass lying to be protected area for an unauthorized person (eg a burglar) is made possible. A burglar has thus relatively quickly access to the issued behind the safety glass valuables, as previous fracture sensors or vibration sensors often do not respond to the use of a gas burner and thus no alarm is triggered. For this reason, in order to identify a heat source in the security area, complex thermal imaging cameras had to be used in order to obtain timely information.

The concept according to the invention consists in providing a glazing arrangement (safety glass) with a reliably functioning safety function by providing an optical waveguide structure on the planar glazing element with one or more optical filter elements, such as e.g. B. one or more Bragg filters, is provided, wherein the optical waveguide structure within a recess or depression in a multi-layered safety glass, z. B. in a capillary or a milled groove, or subsequently applied to the safety glass in capillaries. Since the center wavelength λ _{B of} a Bragg filter depends both on a mechanical elongation and on a heat effect, mechanical or thermal stresses of the planar glazing element caused by third parties can now be very rapidly due to a transfer of the applied mechanical or thermal stress to the optical filter element or almost in real time, for. B. within a few seconds, as an attempted manipulation, such. B. a burglary detected on the flat glazing element and an electronic alarm are triggered to disturb the unauthorized person or to alert a security service or the police.

In addition, a plurality of Bragg filters within the optical waveguide structure, each having a different center wavelength λ _B , are optically connected in series, so that the optical waveguide structure can also be used simultaneously as a rupture sensor. This is possible according to the invention, since in the direction of the coupled-in signal after the respective breakage of the planar glazing element and thus of the optical waveguide structure no signals reflected by the following Bragg filters return to the detection device. Thus, depending on the selected local distribution of the Bragg filter also a (at least rough) localization of Breakage take place on the flat glazing element.

A typical optical waveguide structure with an optical filter element embodied as a Bragg filter has a diameter of 80-200 μm, for example, so that it can be attached to the flat glazing element, for example, in small capillaries or milled grooves with a diameter of 200-650 μm. Typical distances of adjacent rows of optical waveguides or of neighboring optical filter elements can be, for example, in the range of 10-100 or 10-40 cm. If, for example, the planar glazing element has a laminated glass, the optical waveguide structure can be located in a capillary behind the first pane (with respect to the outside of the planar glazing element). As already mentioned above, it is possible to connect a plurality of Bragg filters in succession in order to ensure a better resolution of a breakage point or also of a location of the action of a mechanical or thermal stress on the planar glazing element. In this case, the required maximum distance to the arrangement of the optical filter elements of the optical waveguide structure can be determined individually by the respective planar glazing element, i. H. whose thermal conductivity or thermal conductivity, are made dependent and adapted.

The inventive concept for a glazing arrangement with a safety function can also be subsequently integrated into an existing safety glass, wherein the light waveguide structure (s) is subsequently individually incorporated into the corresponding recesses or recesses (eg capillary or groove) by means of a foil Safety glass to be selected distance to the flat glazing element to be glued. As already stated above, precise values for the exact positioning of the optical waveguide structure with the optical filter elements can be based on the thermal conductivity or the thermal conductivity of the respective safety glass or laminated glass.

By means of trained as a break, strain and heat sensor optical waveguide structure can be very effective (relatively) large amounts of heat mm, z. B. a gas burner, very fast and almost in real time detect. Today's gas burners have a heat radiation of more than 1900 ° Celsius and a power of over 50 kW. In addition to the amount of heat supplied and the resulting change in the respective center wavelengths λ _{B of} the Bragg filter concerned can be simultaneously mechanical effects z. B. in the form of an elongation or fracture in parallel. Incorrect measurements or disturbances of the measurements, such as those caused by solar radiation, can be excluded, for example, by evaluating individual optical filter elements as reference filters or adjacent Bragg filters in order to prevent any incorrect assessment of a measurement result. Thus, for example, a comparison value with which the respective measured value of the reflective optical signal or a variable derived therefrom is compared can be provided with a correction factor which is determined, for example, on an average value or a quantity derived therefrom of a plurality of preceding measured values of the detection signal. Accordingly, the comparison value can also be determined based on or from an average value of all detected reflection components in the reflection signal.

The glazing assembly according to the invention with security function is not only applicable to the prevention or detection of burglaries, but also to security-related applications in which planar glazing elements z. B. are exposed to strong thermal or mechanical loads and also any increased mechanical or thermal load conditions to be determined as quickly as possible or almost in real time. Thus, for example, the glazing arrangement according to the invention with safety function on the windshield of a train cockpit or other vehicle or rail vehicle used and monitored according to the procedure of the invention. In this context, it should be noted that an optical waveguide structure with an optical filter element, which is designed as a break, strain or thermal sensor, is substantially insensitive to electrical or electromagnetic interference signals and thus extremely reliable and insensitive to interference can perform the respective monitoring function.

The inventive glazing arrangement with safety function thus enables the optical waveguide structure designed as strain, fracture and thermal sensor to directly supply the required information with regard to the mechanical or thermal stress of the planar glazing element to be monitored, and thus no different sensor types for detecting heat, strain and fracture needed. In this context, it should be noted that so far for the identification of a heat source in the security area i. A. elaborate thermal imaging cameras were used, a timely information should be obtained.

The concept according to the invention for a safety glass can thus be used everywhere where valuables or other goods are in front of you unauthorized access or access should be secured, such. As banks, jewelers, department stores, etc. In addition to this burglary prevention or safety aspect, the inventive concept can be used equally on flat glazing elements that are relatively strong mechanical or thermal stresses exposed to use, to excessive mechanical or thermal stress of the respective planar glazing element as early as possible or almost in real time to capture.

Although some aspects have been described in the context of a device, it will be understood that these aspects also constitute a description of the corresponding method, so that a block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding block or detail or feature of a corresponding device. Some or all of the method steps may be performed by a hardware device (or using a hardware device). Device), such as a microprocessor, a programmable computer or an electronic circuit. In some embodiments, some or more of the most important method steps may be performed by such an apparatus (sensor interrogator).

Depending on particular implementation requirements, embodiments of the invention may be implemented in hardware or in software. The implementation may be performed using a digital storage medium, such as a floppy disk, a DVD, a Blu-ray Disc, a CD, a ROM, a PROM, an EPROM, an EEPROM or FLASH memory, a hard disk, or other magnetic disk or optical memory are stored on the electronically readable control signals that can cooperate with a programmable computer system or cooperate such that the respective method is performed. Therefore, the digital storage medium can be computer readable. Thus, some embodiments according to the invention include a data carrier having electronically readable control signals capable of interacting with a programmable computer system such that one of the methods described herein is performed.

In general, embodiments of the present invention may be implemented as a computer program product having a program code, wherein the program code is operable to perform one of the methods when the computer program product runs on a computer. The program code can also be stored, for example, on a machine-readable carrier. Other embodiments include the computer program for performing any of the methods described herein, wherein the computer program is stored on a machine-readable medium.

In other words, an embodiment of the method according to the invention is thus a computer program which has a program code for performing one of the methods described herein when the computer program runs on a computer.

A further embodiment of the inventive method is thus a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program is recorded for carrying out one of the methods described herein.

Another embodiment includes a processing device, such as a computer or a programmable logic device, that is configured or adapted to perform one of the methods described herein.

Another embodiment includes a computer on which the computer program is installed to perform one of the methods described herein.

In some embodiments, a programmable logic device (eg, a field programmable gate array, an FPGA) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. In general, in some embodiments, the methods are performed by any hardware device. This may be a universal hardware such as a computer processor (CPU) or hardware specific to the process, such as an ASIC.

The embodiments described above are merely illustrative of the principles of the present invention. It will be understood that modifications and variations of the arrangements and details described herein will be apparent to others of ordinary skill in the art. Therefore, it is intended that the invention be limited only by the scope of the appended claims, rather than by the specific details of the claims be presented with reference to the description and explanation of the embodiments herein.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• DIN V ENV 1627 [0002]
• DIN EN 356 [0002]

Claims (18)

Glazing arrangement ( 10 ) with safety function, having the following features: a flat glazing element ( 20 ); and an optical waveguide structure ( 30 ) with an optical filter element ( 32 ); wherein the optical waveguide structure ( 30 ) mechanically on the glazing element ( 20 ) is arranged in order for a mechanical or thermal stress of the planar glazing element ( 20 ) a change of an optical property of the optical waveguide structure ( 30 ) to effect. Glazing arrangement according to claim 1, wherein the optical filter element ( 32 ) comprises a Bragg filter or a plurality of Bragg filters. Glazing arrangement according to claim 1 or 2, wherein the optical waveguide structure ( 30 ) a plurality of serially arranged, spaced apart optical filter elements ( 32 ) in the form of Bragg filters, the Bragg filters each having a different filter center wavelength. Glazing arrangement according to claim 3, wherein the optical waveguide structure ( 30 ) is arranged so that the Bragg filters ( 32 ) in a distributed arrangement or in a grid on the planar glazing element ( 20 ) are arranged. Glazing arrangement according to one of the preceding claims, wherein the optical waveguide structure with positive, cohesive or material fit with the planar glazing element ( 20 ) connected is. Glazing arrangement according to one of the preceding claims, wherein the change in the optical property of the optical waveguide structure based on a force and / or temperature-dependent material strain or on a temperature-dependent refractive index change of the material of the formed as a Bragg filter optical filter element. Glazing arrangement according to one of the preceding claims, further comprising: a further optical waveguide structure ( 30 ' ) with at least one further optical filter element ( 32 ' ) in the form of a Bragg filter. Glazing arrangement according to claim 7, wherein the further optical waveguide structure ( 30 ' ) a plurality of serially arranged, spaced apart optical, further filter elements ( 32 ' ) in the form of Bragg filters, the Bragg filters each having a different filter center wavelength. Security system ( 70 ) for glazing, comprising: a glazing assembly ( 10 ) with safety function according to one of claims 1 to 8; a signal input device ( 80 ) for coupling an optical signal (S ₁ ) into the optical waveguide structure ( 30 ); a signal detection device ( 82 ) for detecting an optical signal (S _R , S _Tr ) of the optical waveguide structure ( 30 ) and outputting an electrical detection signal (S _e ) based on the detected optical signal (S _R , S _Tr ); and a processing device ( 90 ) for driving the signal input device ( 80 ) and for evaluating the signal acquisition device ( 82 ) provided detection signal, wherein the processing device ( 90 ) is adapted to a change of the optical property of the optical waveguide structure ( 30 . 32 ) due to a mechanical or thermal stress of the planar glazing element ( 20 ) to investigate. Security system according to claim 9, wherein the processing device ( 90 ) is configured to compare the detection signal (S _e ) or a signal derived therefrom with a comparison value, in order to determine whether the detection signal (S _e ) is within or outside a desired range, wherein an exit of the desired range is exceeded Limit value for mechanical or thermal loading of the planar glazing element ( 10 ). A security system according to any one of claims 8 to 10, wherein the comparison value is based on an average or derived magnitude of a plurality of previous measurements of the detection signal of a Bragg filter or a plurality of Bragg filters. A security system according to any one of claims 8 to 11, wherein the detection signal (S _e ) or the signal derived therefrom is based on a center wavelength (λ _B ) of the respective Bragg filter or on a power level of the detected signal. Security system according to one of claims 8 to 12, wherein the processing device ( 90 ) is adapted to output a warning or alarm signal (S _out ), if exceeding a limit value for a mechanical or thermal load of the planar glazing element ( 20 ) occurs. Safety system according to one of claims 8 to 13, wherein the optical waveguide structure ( 30 ) a plurality of filter elements ( 32 ) in the form of Bragg filters each having a different filter center wavelength (λ _B ). Method for detecting a mechanical or thermal stress of a planar glazing element ( 20 ), wherein on the planar glazing element ( 20 ) an optical waveguide structure ( 30 ) with an optical filter element ( 32 ) is mechanically arranged, with the following steps: coupling in ( 102 ) of an optical signal in the optical waveguide structure; To capture ( 104 ) an optical signal of the optical waveguide structure and generating an electrical detection signal based on the detected optical signal of the optical waveguide structure; Evaluate ( 106 ) of the electrical detection signal or a signal derived therefrom to detect a change in the optical property of the optical waveguide structure due to mechanical or thermal stress of the planar glazing element. The method of claim 15, further comprising the step of: comparing ( 108 ) of the electrical detection signal or the signal derived therefrom with a comparison value to determine whether the detection signal is outside a desired range, indicating an exceeding of a limit value for mechanical or thermal loading of the planar glazing element. The method of claim 16, wherein the comparison value is fixed or is determined based on a statistical processing of a plurality of previous measurements of the electrical detection signal of one or a plurality of Bragg filters. Computer program with a program code for carrying out the method according to one of claims 15 to 17, when the program runs on a computer or a microprocessor.

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