Protective device for high-energy radiation generated by a radiation source

Abstract

A protective device for high-energy radiation (X) generated by a radiation source, comprising at least one active sensor layer (2.2) pointing in the direction of the incident radiation, which active sensor layer generates a signal upon impact of high-energy radiation, which signal switches off the radiation source when a limit value is exceeded or undershot, wherein a controllable protective layer (2.4) is arranged above the active sensor layer (2.2), the radiation absorption, deflection or reflection behavior of which is adjustable, wherein the active sensor layer generates a signal upon penetration of high-energy radiation, which increases the radiation absorption, deflection or reflection behavior of the controllable protective layer and limits the radiation flux to the underlying active sensor layer.

Description

[0001] The invention relates to a protective device for high-energy radiation generated by a radiation source, in particular laser radiation, and to the use of such an arrangement for the controllable active protection of an object, a person, animals or plants from such radiation.

[0002] Increasingly high-energy radiation sources, especially lasers, are being used for technical and medical procedures. Modern lasers, for example, can easily cut and penetrate stone, concrete, masonry, or even steel. Such high-energy lasers are typically operated in an enclosure that protects the surrounding area from escaping laser light. However, it is often necessary to adapt the operating conditions of lasers to specific processes. This requires technical personnel to perform adjustments and settings, or other maintenance work, on the laser within this enclosure. Appropriate laser safety devices such as laser safety curtains or laser protective clothing are used for this purpose.

[0003] Protective devices for high-energy radiation are well known and widely used. For example, passive protective devices, such as lead aprons, are used primarily to protect against X-rays. In addition, a variety of radiation protection devices, such as radiation shields or clothing, are known. For example, laser safety goggles are commercially available, which absorb or reflect a laser beam and thereby protect the human eye.

[0004] Typical laser protection devices usually have a passive protective layer that reflects incoming laser light or attenuates the transmitted light by absorbing the radiation energy. Such passive laser protection materials include, for example, ceramic materials, which are destroyed or ablated upon impact by laser light. However, the intensity of the radiation can also increase to such an extent that the passive laser protection is destroyed or cannot withstand the radiation for a sufficient length of time. The beam then penetrates the protective material, creating holes without the working personnel being immediately aware of this.

[0005] Attempts have therefore already been made to place an active layer after this passive layer. This active layer triggers a signal when a beam passes through the passive layer and hits the active layer, shutting down the laser. If this happens, the laser protection device is usually irreversibly damaged and cannot be easily repaired. To protect this active layer, another passive protective layer is usually placed on top.

[0006] Active laser protection is not yet widely used. Currently, it is not possible to adjust the trigger threshold for the detection or stop signal. However, the active layer is often destroyed when a signal is triggered. Selective adjustment of passive protection before active protection is not yet possible and is unknown.

[0007] A typical laser safety device with a safety shutdown is described, for example, in DE 10 2006 053 579 A1. A sensor is arranged behind a passive laser safety barrier. This sensor is connected to the laser via a threshold switch and shuts off the laser when a received detector signal exceeds or falls below a threshold. Another example of a laser safety barrier is known from DE 199 40 476 A1.

[0008] DE 10 2012 106 278 A1 discloses a laser protection device that also has a sensor layer arrangement. The sensor layer arrangement has a predetermined electrical characteristic and is designed such that the electrical characteristic changes upon energy input due to impingement of laser radiation. Such a laser protection device is also arranged behind a passive protective wall, which absorbs or reflects incoming laser radiation. Only when this wall is penetrated by the laser light does light strike the sensor arrangement, which leads to the deactivation of a laser.

[0009] Such active protective layers contain sensors, which are usually made of wires that melt when laser light hits them, interrupting a current flow and turning off the laser. However, this irreversibly destroys the active layer and renders the protective device unusable.

[0010] EP 1 998 194 discloses an optical protection filter which, in a preferred embodiment, comprises one or more controllable and self-darkening optical filter layers to influence or vary the visible light transmission. Various controllable layers and modulators, as well as electrochromic materials, are also mentioned.

[0011] The invention therefore aims to provide an active laser protection device in which the required protection level can be adapted to the respective operating conditions. This makes it possible, for example, to prevent the active layer from being irreversibly destroyed when the laser light penetrates the passive protective layer during maintenance, repair, or adjustment work.

[0012] The invention therefore also aims to maintain the lifetime of the active layer as long as possible.

[0013] This object is now achieved according to the invention by the features of claim 1.

[0014] Accordingly, it is proposed to arrange a further protective layer over the active protective layer or sensor layer, the absorption and / or reflection behavior of which can be selectively or individually adjusted and which protects the underlying active sensor layer. A variety of materials are suitable for this purpose, such as photochromic, electrochromic, thermochromic and / or thermotropic substances or so-called "smart" glass, i.e. glasses whose light transmittance can be changed by applying electrical voltage, light irradiation or heating. Switchable mirrors, polymer disperse liquid crystal layers (PDLC) and so-called suspended particle devices (SPD) are also suitable. Rare earth-doped CaF2 or quartz glass, as well as the reversible or irreversible laser-induced formation of absorption centers using conventional materials, are also suitable.

[0015] According to the invention, the active protective layer (sensor layer) registers penetrating laser light and generates a signal that is used to control the selectively adjustable or controllable protective layer, thus increasing the absorption or reflection of the incident radiation. This prevents premature triggering of an alarm and greatly attenuates the radiation energy striking the active sensor layer, thus preventing its destruction. Since such layers made of the aforementioned materials react quite quickly, the invention makes it possible to protect the active sensor layer from rapid destruction.

[0016] In principle, it is also possible to preset the adjustable protective layer. In a particularly preferred embodiment, the absorption or reflection of the adjustable protective layer is preset so that weak penetrations through the outer passive layer do not immediately lead to the destruction of the active sensor layer.

[0017] Since radiation penetration can also damage the active sensor layer, e.g., a photodiode or solar cell, it has proven useful to detect the generated thermal radiation using an IR detector, e.g., at 50-150°C. Such a detector can be positioned upstream or downstream of the adjustable protective layer or the sensor layer, depending on the radiation direction.

[0018] Furthermore, it has often proven useful to add an additional layer for passive, or even active, heat conduction. This makes it possible to further protect the active sensor layer, as well as objects and people behind the entire radiation protection arrangement.

[0019] Typically, a passive protective layer is arranged beneath the active sensor layer, which provides additional protection in the event of radiation penetrating the active sensor layer.

[0020] In addition, it has proven useful to apply another passive protective layer, usually with a lower protection class than the bottom layer, in front of the adjustable protective layer, in the direction of any laser light that might penetrate. Only when light passes through the first passive laser protection layer onto the underlying active sensor layer is a signal (voltage, current, or light) generated.

[0021] The protective device according to the invention can be designed as a wall, a curtain, or even as clothing. It is preferably designed as a flexible sheet.

[0022] In a preferred embodiment, the invention also relates to the use of the device for protecting sensitive objects, humans, animals and / or plants from high-energy radiation.

[0023] The invention will be explained in more detail below using an example. Fig. 1 shows a structure of a protective device according to the prior art. Fig. 2 shows a typical structure of a protective arrangement according to the invention.

[0024] The state of the art according to Fig. 1, an active protective layer 1.2 is arranged on the passive protective layer 1.1. Upon impact with high-energy radiation X, the active protective layer sends a signal via signal path 1.5 (usually an electrically conductive connection) to a control unit 1.6, which then deactivates the high-energy radiation X or its source. The active sensor layer 1.2 is then covered again by a passive protective layer 1.3 to prevent false alarms or premature destruction of the active sensor layer 1.2.

[0025] In the embodiment according to the invention Fig. 2 is like Fig. 1 an active layer 2.2 is arranged above the passive layer 2.1, over this active layer 2.2 the new controllable protective layer 2.4 according to the invention is then arranged, which as in Fig.1 is protected by an additional outer passive protective layer 2.3. High-energy radiation X now penetrates the outer passive protective layer 2.3 and the adjustable protective layer 2.4, striking the active layer 2.2, which transmits a signal via signal path 2.5 to the control unit 2.6. The control unit 2.6 then quickly increases the absorption or reflection of the adjustable protective layer via line 2.7, thus reducing the damage to the passive protective layer 2.1.

[0026] In principle, the device according to the invention also makes it possible to preset the absorption or reflection of the adjustable protective layer 2.4 via line 2.7 in order to prevent premature triggering of an alarm.

[0027] This adjustable protective layer 2.4, as well as the other layers, can be configured independently of one another, either as a single layer or as multiple layers. In the example, the active protective layer is, for example, a flexible solar cell or a photodiode. In principle, it is also possible to use the fusible wires described so far for this purpose. The adjustable protective layer according to the invention is then arranged over this active layer, which regulates the light incidence on the underlying active sensor layer.

[0028] In one embodiment of the invention, this is advantageously a photochromic protective layer which darkens by applying an electrical voltage, ie increases the absorption of light passing through.

[0029] In a further practical embodiment, a further passive protective layer, usually with a lower protection class than the bottom layer, is arranged in front of the photochromic protective layer in the direction of any laser light that might penetrate. If light now passes through the first passive laser protection layer onto the underlying active sensor layer, this generates a signal (voltage, current or light). If the measurement signal exceeds a previously adjustable threshold, an alarm is triggered and / or the radiation source is switched off. At the same time, the generated signal can also be used to increase the absorption, deflection and / or reflection of the adjustable protective layer or adjustable protective layer system above it and to limit the radiation flux on the underlying active sensor layer. Furthermore, by applying a voltage to the photochromic layer, the light flux can be preset or adjusted for adjustment and maintenance work.be limited.

Claims

[1] A protective device for high-energy radiation (X) generated by a radiation source, comprising at least one active sensor layer (2.2) pointing in the direction of the incident radiation, which active sensor layer generates a signal upon impact of high-energy radiation which switches off the radiation source when a limit value is exceeded or undershot, wherein a controllable protective layer (2.4) is arranged above the active sensor layer (2.2), the radiation absorption, deflection or reflection behavior of which is adjustable, wherein the active sensor layer generates a signal upon penetration of high-energy radiation which increases the radiation absorption, deflection or reflection behavior of the controllable protective layer and limits the radiation flux to the active sensor layer below. [2] Protective device according to claim 1, characterized by that the high-energy radiation is laser radiation. [3] Protective device according to claim 1 or 2, characterized by that a passive layer (2.1) is arranged under the active sensor layer (2.2). [4] Protective device according to one of the preceding claims, characterized by that a further passive protective layer (2.3) is arranged above and / or below the adjustable protective layer (2.4), which protects the underlying layers. [5] Protective device according to one of the preceding claims, characterized by that the active sensor layer (2.2) is a photovoltaic unit, a gas cell, a photodiode, a fuse wire and / or an IR detector. [6] Protective device according to one of the preceding claims, characterized by that the controllable protective layer (2.4) is an electrochromic, thermochromic, photochromic, a PDLC or SPD layer or a switchable mirror. [7] Protective device according to one of the preceding claims, characterized bythat the switchable mirror contains a metal hybrid. [8] Protective device according to one of the preceding claims, characterized by that the arrangement has at least one layer for passive heat dissipation. [9] Protective device according to one of the preceding claims, characterized by that the arrangement has at least one layer containing fibers which deflect and / or scatter incident light. [10] Use of a protective device according to one of the preceding claims for protecting sensitive objects, people, animals and / or plants.

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